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  • IPEN-DOC 28760

    FREITAS, G.R. ; SOUZA, CARLA D. de . Information management methodology in the control of radiation exposure in computed tomography exams. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... 2021.

    Abstract: In many Brazilian hospitals, computed tomography (CT) is the imaging equipment with greater ionization capability. Systems for monitoring and managing information are not mandatory and the high monetary value for the 'software' acquisition and training results in the non-investigation of the radiation dose received by the patient. Thus, there is a greater likelihood of unnecessary exposures increasing the probability of damage from exposure to ionizing radiation. These can occur because of exams performed out of protocol, poorly referred, repetition in short intervals of time, and operational failures due to malpractice and lack of training of the professionals involved. International organizations such as Image Gently and Latin Safe promote awareness campaigns every year to reduce and control the exposure dose of patients, with monitoring being a pillar for prevention and reducing patient exposure. The present work developed a low-cost methodology, using free tools for storing and evaluating the DICOM-Structured Report (DICOM-SR) and interpreting these data, which can become an economically viable resource for all diagnostic imaging services of the free Brazilian Unified Health System (SUS). A total of 13,734 exams from 9,911 patients were analyzed from September 2019 to August 2021, divided into groups according to their age group. The program was used specially to optimize the head CT protocol. After the first year of training results showed a radiation dose reduction of 11.7%. The new system provides free and simple monitoring of the number of CT scans and the dose received in comparison with the protocols, which, in turn, will result in clinical recommendations for improving procedures and training.

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  • IPEN-DOC 28753

    SCALISE, LEVY ; BURIMOVA, ANASTASIA ; PEREIRA, LUCIANO F. ; FERREIRA, WANDERSON ; SALES, TATIANE ; GONÇALVES, VITOR ; CABRERA-PASCA, GABRIEL; SAXENA, RAJENDRA N. ; CARBONARI, ARTUR W. . DFT-based Calculations of the Magnetic Hyperfine Interactions at Cd Sites in RECd Compounds with the FP-LAPW ELK Code. In: ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS, 65th, November 2-6, 2020, Online. Abstract... 2020.

    Abstract: In this work we tested the methodology to map magnetic hyperfine interactions in strongly correlated materials using a free open-source all-electron FP-LAPW code ELK. The RECd (RE = Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) series was chosen as a laboratory system, since an almost complete set of experimental data on the hyperfine parameters at Cd sites in these compounds was acquired previously with an extremely sensitive TDPAC technique [1]. Moreover, these TDPAC results were complemented with WIEN2k DFT calculations that allow a qualitative comparison of the two codes. The ELK calculations were performed with PBE96 GGA-type exchange-correlation functional, the cases of scalar relativistic approximation and fully relativistic relaxation of the states were treated separately. A dense k-mesh and adequate R(MT)K(max) were chosen in both cases to comply with the sensitivity of magnetic hyperfine parameters. We emphasize that the exploited version of ELK accounted for the contact field only. Yet, as it is the only contribution expected for Cd site in RECd, the values of B(hf), albeit generally overestimated, have shown reasonable agreement with the experiment (Fig. 1). Spin-orbit coupling taken into account led to a decrease in deviation from experimental data. An addition of the Hubbard-like term was essential to reach a tolerable result for CeCd. This behavior may be associated with a weaker localization of the 4f electron of Ce. Concerning the potential sources of discrepancy between our ELK results and those previously obtained with WIEN2k, (i) a different way of accounting for relativistic corrections, (ii) the use of GGA (our ELK study) versus LDA (previous WIEN2k study) and other details are discussed.

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  • IPEN-DOC 28752

    MATOS, IZABELA T. ; SALES, TATIANE S. ; CABRERA-PASCA, GABRIEL; BURIMOVA, ANASTASIA ; SAXENA, RAJENDRA N. ; PEREIRA, LUCIANO F. ; OTUBO, LARISSA ; CARBONARI, ARTUR W. . Synthesis and characterization of Fe3O4-HfO2 nanoparticles by magnetization and hyperfine interactions measurements. In: ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS, 65th, November 2-6, 2020, Online. Abstract... 2020.

    Abstract: Nanoparticles (NPs) that combine biocompatibility and enhanced physical characteristics for biomedical applications are currently an area of intense scientific research. Hafnium oxide NPs is an innovative approach in the anticancer treatment by radiotherapy due to their low toxicity and enhancement of local dose in the tumor reducing the total radiation dose for the patient [1]. The combination of this amazing property with the excellent magnetic hyperthermia performance of Fe3O4 NPs can produce a promising nanomaterial for cancer therapy. In the present work, we have synthesized NPs samples of Fe3O4 doped with 10%Hf and HfO2 doped with 10% Fe by chemical procedures. The samples had their morphological, structural, and magnetic properties characterized by some results being displayed in Fig. 1. The crystal structure of the samples was characterized by X-ray Diffraction (XRD), whose results present a single phase. Transmission Electron Microscopy (TEM) images show spherical and hexagonal NPs with an average size of 12 nm as displayed in Fig. 2. The magnetic property was investigated by magnetization measurement. The results from the temperature dependence of ZFC-FC magnetization show a large peak in the ZFC curve corresponding to a broad distribution of blocking temperatures as shown in Fig. 1(b). Fortunately, when irradiated with neutrons in a research reactor, the nuclear reaction 180Hf(n,γ)181Hf yields the probe nucleus 181Hf(181Ta) used by the perturbed angular correlations (PAC) technique to measure hyperfine interactions. Both samples show electric quadrupole interaction characteristics of the HfO2 phase indicating that the Fe replaces Hf in HfO2 NPs, but rather than substituting Fe, Hf form HfO2 NPs diluted in Fe3O4 NPs. Moreover, a pure time-dependent magnetic dipole interaction below 300 K was observed for Fe3O4 NPs mixed with 10% of HfO2.

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  • IPEN-DOC 28751

    RODRIGUES, PRISCILA S. ; MATOS, IZABELA T. ; SALES, TATIANE S. ; BURIMOVA, ANASTASIA ; CABRERA-PASCA, GABRIEL; PEREIRA, LUCIANO F. ; SAXENA, RAJENDRA N. ; OTUBO, LARISSA ; CARBONARI, ARTUR W. . Annealing effect on the structural and local magnetic properties of nickel ferrite nanoparticles studied by hyperfine interaction measurements. In: ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS, 65th, November 2-6, 2020, Online. Abstract... 2020.

    Abstract: Nickel ferrite in the form of nanoparticles is a technologically important material that can be applied for the production of biosensors, catalysts, drug delivery, and magnetic resonance contrast agents. In this work NiFe O samples comprising spherical nanoparticles of ~6 nm in diameter have been synthesized via a thermal decomposition route. The quality control of the samples was carried out with conventional techniques including X-ray diffraction and transmission electron microscopy. Post-synthesis XRD pattern revealed textured spinel NiFe O . Local magnetic properties were examined with Time Differential Perturbed Angular Correlation (TDPAC) spectroscopy within the 12 - 773K temperature range with In( Cd) probe introduced into the samples at synthesis. Quasi-static magnetic properties were observed (including above room temperature), as expected due to the small time window of TDPAC. The TDPAC results shown in Fig. 1 were analyzed using a model with combined electric quadrupole and magnetic dipole interactions. An expressive dynamic interaction was observed upon heating after synthesis. A theoretical model based on the Brillouin function for different ionic moments was applied to study the evolution of the hyperfine magnetic field with temperature (see Fig. 1-2) and allowed to attribute the magnetic interaction to the probe location at Fe3+ site. Site occupancy and the interplay between magnetic and structural properties are discussed with respect to application perspectives.

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  • IPEN-DOC 28750

    CABRERA-PASCA, G.A.; MAGNO, J.F.; FERREIRA, W.L. ; CAMPOS, A.C. ; BOSCH-SANTOS, B.; SALES, T.S.N. ; PEREIRA, L.F.D. ; BURIMOVA, A. ; SAXENA, R.N. ; FREITAS, R.S.; CARBONARI, A.W. . Local inspection of magnetic properties in GdMnIn by measuring hyperfine interactions. In: ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS, 65th, November 2-6, 2020, Online. Abstract... 2020.

    Abstract: GdMn2 is a member of a series of Laves phase containing a rare-earth element and a magnetic 3dtransition metal with very peculiar magnetic properties[1]. Doping with a non-magnetic element such as indium affects these properties[2,3]. GdMnIn is reported to crystalize in the hexagonal MgNi2-type structure presenting a spin-glass behavior with no magnetic order attributed to the triangular spin frustration of magnetic ions[3]. The observed absence of long-range interactions by magnetization measurements along with the almost impossible measurements with neutron diffraction due to the presence of Gd with very high neutron absorption cross section makes the investigation of local exchange interactions in this compound very difficult. In the present work, measurements of hyperfine interactions at In sites using 111In(111Cd) probe nuclei were carried out by perturbed angular correlations (PAC) technique to investigate the local magnetic exchange in GdMnIn compound. Results displayed in Fig. 1 for the behavior of the major component (Vzz) of the electric field gradient (efg) tensor and the distribution of electric quadrupole frequency () show a strong instability of the electronic environment of In sites when temperature decreases indicating a Mn-In disorder. The weak magnetic hyperfine field at In sites also shown in Fig.1 with an anomalous temperature dependence below around 140 K along with the increase in the angle between Bhf and Vzz directions suggest a weak long-range exchange interaction.

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  • IPEN-DOC 23980

    TOMACHUK, C.R. ; ELSNER, C.I.; DI SARLI, A.R.; CULCASI, J.D.; COSTA, I. . Trivalent chromium conversion layer: a way of enhancing the electrogalvanized steel corrosion protection. In: ANNUAL MEETING OF THE INTERNATIONAL SOCIETY OF ELECTROCHEMISTRY, 61st, September 26 - October 1, 2010, Nice, France. Abstract... 2010.

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  • IPEN-DOC 23962

    QUEIROZ, F.M. ; ELSNER, C.I.; DI SARLI, A.R.; TOMACHUK, C.R. ; COSTA, I. . Effect of Cr III passivation on the corrosion resistance of coated electrogalvanized steel. In: INTERNATIONAL SYMPOSIUM ON PASSIVITY OF METALS AND SEMICONDUCTORS, 10th, 10-14 April, 2011, Florianopolis, SC. Abstract... 2011.

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  • IPEN-DOC 22847

    MARTINS, EMERSON A. ; MELO, HERCILIO G. de; COSTA, ISOLDA . Using EIS to assess the protection afforded by phosphate layers to PM produced Nd-Fe-B Magnets. In: ECS MEETING, 216th, October 4-9, 2009, Vienna, Austria. Abstract... 2009.

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  • IPEN-DOC 22806

    NETO, MOISES A.M.; DEUS, ENEIO P. de; COSTA, I. ; CORREA, O.V. ; SOBRAL, ANA V.C.. Influência da corrosão no aço inoxidável duplex em solução de cloreto concentrado. In: CONGRESSO BRASILEIRO DE P&D EM PETRÓLEO E GÁS, 1., 25-28 de novembro, 2001, Natal, RN. Resumo... 2001. p. 263.

    Palavras-Chave: stainless steels; corrosion resistance; chlorides; mechanical properties; metallography

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  • IPEN-DOC 22473

    COSTA, ISOLDA ; MARTINS, EMERSON A. ; MELO, HERCILIO G. de. Corrosion resistance of sintered Nd-Fe-B magnets corrosion and surface treatments for corrosion protection. In: ECS MEETING, 216th, October 4-9, 2009, Vienna, Austria. Abstract... 2009.

    Palavras-Chave: sintering; neodymium; iron; boron; phosphates; surface treatments; corrosion resistance

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  • IPEN-DOC 22472

    FONTES, T.F. ; TERADA, M.; PADILHA, A.F.; MAGNABOSCO, R.; COSTA, I. . Sensibility of mechanical and electrochemical tests in detecting alpha prime phase in duplex stainless steels aged at 475 ºC. In: INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS, 11th, September 20-25, 2009, Rio de Janeiro, RJ. Abstract... 2009.

    Abstract: Alpha prime formation leads to material embrittlement and decreases corrosion and mechanical resistance. In the present study, some tests as microhardness, impact test, electrochemical impedance spectroscopy and cyclic polarization were performed with the duplex stainless steel (DSS) UR 52N+aged at 475 ºC from 0.5 h to 1,032 h in order to evaluate the sensibility of these tests in detecting alpha prime presence. After 0.5 h of aging at 475 ºC it was observed that impact test indirectly revealed the presence of this deleterious phase in the DSS studied, and this test was the most sensible for detecting alpha prime among the other ones used.

    Palavras-Chave: stainless steels; corrosion resistance; microhardness; mechanical properties

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  • IPEN-DOC 22471

    MARQUES, R.A. ; TERADA, M.; SALIBA-SILVA, A.M. ; PADILHA, A.F.; COSTA, I. . The comparison of the corrosion resistance of advanced ferritic stainless steels by Mott-Schottky approach. In: INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS, 11th, September 20-25, 2009, Rio de Janeiro, RJ. Abstract... 2009.

    Abstract: Ferromagnetic stainless steels (SS) have been investigated as potential candidates for dental prosthesis applications in replacement of magnetic attachments made of noble and expensive alloys. In order to be used as biomaterials, their corrosion resistance has to be appropriate. The corrosion resistance of passive materials is related to the characteristics of the passive film formed and this property might be investigated by Mott-Schottky procedure. The capacitance of passive films formed during 2 days of immersion in a Phosphate Buffered Solution (PBS), at room temperature on PM2000, DIN 1.4575 and 17-4 PH ferritic stainless steels (SS) was studied by Mott-Schottky approach. A commercial alloy was also analyzed for comparison reasons. The results showed that films on tested materials behave as both, n-type and p-type semiconductors and the PM2000 presented the highest corrosion resistance among all materials studied.

    Palavras-Chave: ferritic steels; biological materials; stainless steels; teeth; prostheses; corrosion resistance; impedance

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  • IPEN-DOC 28653

    GARCIA, VANESSA S.G. ; TALLARICO, LENITA de F.; ROSA, JORGE M. ; NAKANO, ELIANA; BORRELY, SUELI I. . Avaliação ecotoxicológica de efluente têxtil submetido a radiação ionizante. In: ENCONTRO BRASILEIRO DE MALACOLOGIA, 27.; SIMPÓSIO LATINO AMERICANO DE JOVENS TAXONOMISTAS, 5., 4-8 de outubro, 2021, Online. Resumo... Rio de Janeiro, RJ: Sociedade Brasileira de Malacologia - SBMa, 2021. p. 162-162.

    Abstract: O setor têxtil demanda elevada quantidade de água para o processo de beneficiamento das fibras, e adicionalmente gera um grande volume de efluente colorido e com diversos contaminantes. Estes são responsáveis por uma parcela importante na degradação dos corpos hídricos em diversas regiões do mundo, causando efeitos adversos aos ecossistemas. Devido a elevada carga tóxica, composição e coloração, geralmente esses efluentes necessitam de tratamentos complementares para melhorar a degradação. Desta forma, tem-se buscado tecnologias mais eficientes para a oxidação destes contaminantes, com ênfase para os processos oxidativos avançados, como a irradiação por feixe de elétrons. O processo com radiação ionizante promove a radiólise da água com formação de radicais hidroxila ou produtos moleculares que atuam na degradação dos compostos orgânicos. O presente estudo dedicou-se a análise da toxicidade aguda de um efluente têxtil (contendo corante reativo Red 239) em dois níveis tróficos do ambiente aquático, o microcrustáceo Daphnia similis e o caramujo Biomphalaria glabrata. A exposição para D. similis foi de 48 horas e o efeito observado foi a imobilidade dos organismos expostos, já para B. glabrata a exposição foi de 24h e observada a letalidade. Os resultados de toxicidade foram expressos pela CE(L)50 (Concentração efetiva/letal mediana). A radiação ionizante por feixe de elétrons foi proposta como tecnologia para tratamento do efluente visando a redução da toxicidade, sendo avaliadas as doses de 2,5 kGy e 5 kGy. As amostras foram irradiadas em Acelerador de Elétrons (Dynamitron®), com energia fixada em 1,4 MeV. A eficiência da irradiação quanto à redução de toxicidade foi obtida a partir dos valores de CE(L)50, transformados para unidade de toxicidade (UT= 100/CE(L)50). Com relação ao efeito agudo para os organismos avaliados, pode-se observar que o efluente bruto foi mais tóxico para o microcrustáceo, com CE50= 9,61% enquanto para B. glabrata foi obtido o valor de CL50=25,09%. As amostras irradiadas, os valores em relação a redução da toxicidade foram melhores se comparados ao efluente bruto: D. similis, CE50%= 12,62 (2,5 kGy); 17,24 (5 kGy), B. glabrata, CL50= 63% (2,5 kGy) e 70,71% (5 kGy). A partir da dose de 2,5 kGy já foi possível observar eficiência em relação a redução da toxicidade para ambos os organismos. Com 5 kGy, a eficiência em relação a redução de efeitos agudos foi superior a 64% em B. glabrata e superior a 44% para D. similis. Os resultados aqui obtidos confirmam que efluentes industriais, como os do setor têxtil, são críticos do ponto de vista de contaminação ambiental, destacando, assim, a necessidade de melhor gerenciamento, tratamento e descarte adequados destes efluentes. Com a tecnologia por feixe de elétrons, foram obtidos dados promissores em termos de tratamento com diminuição significativa da toxicidade.

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  • IPEN-DOC 28652

    GARCIA, VANESSA S.G. ; TOMINAGA, FLAVIO K. ; BOIANI, NATHALIA F. ; SILVA, THALITA T. ; ROSA, JORGE M. ; BORRELY, SUELI I. . Avaliação da toxicidade de surfactantes não iônico e aniônico submetidos a tratamento por feixe de elétrons. In: CONGRESSO BRASILEIRO DE ECOTOXICOLOGIA, 16., 16-19 de agosto, 2021, Online. Resumo expandido... 2021.

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  • IPEN-DOC 20150

    QUEIROZ, F.M. ; SERE, P.R.; ELSNER, C.I.; DI SARLI, A.R.; TOMACHUK, C.R.; COSTA, I. . Study of the corrosion behavior of electrogalvanised steel/Cr(III) and Zr conversion layer/paint system by electrochemical and visual methods. In: EUROPEAN CORROSION CONGRESS, September 8-12, 2014, Pisa, Italy. Abstract... 2014.

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  • IPEN-DOC 17283

    BARDI, MARCELO A.G. ; MUNHOZ, MARA de M.L. ; MACHADO, LUCI D.B. . Effect of transition metal salts on color, gloss and hardness of EB-cured pigmented coatings for polymeric substrates. In: INTERNATIONAL CONFERENCE ON DEVELOPMENTS AND APPLICATIONS OF NUCLEAR TECHNOLOGIES, September 11-14, 2011, Krakow, Poland. Abstract... 2011. p. 63-63.

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  • IPEN-DOC 15721

    MARTINS, J.F.T. ; COSTA, F.E. ; SANTOS, R.A. ; MESQUITA, C.H. ; HAMADA, M.M. . A comparative study on the performance of radiation detectors from the HgI2 crystals grown by different techniques. In: INTERNATIONAL CONFERENCE ON DEVELOPMENTS AND APPLICATIONS OF NUCLEAR TECHNOLOGIES, September 11-14, 2011, Krakow, Poland. Abstract... 2011. p. 192-192.

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  • IPEN-DOC 15453

    CALVO, WILSON A.P. ; MESQUITA, CARLOS H. de ; SPRENGER, FRANCISCO E. ; COSTA, FABIO E. da ; SALVADOR, PABLO A.V. ; CARVALHO, DIEGO V. de S. ; HAMADA, MARGARIDA M. . Development of the mechanical system on a third-generation industrial computed tomography scanner in Brazil. In: INTERNATIONAL CONFERENCE ON DEVELOPMENTS AND APPLICATIONS OF NUCLEAR TECHNOLOGIES, September 11-14, 2011, Krakow, Poland. Abstract... 2011. p. 133-133.

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  • IPEN-DOC 15342

    SOMESSARI, SAMIR L. ; FEHER, ANSELMO ; SPRENGER, FRANCISCO E ; ROSTELATO, MARIA E.C.M. ; MOURA, JOAO A.; COSTA, OSVALDO L. ; CALVO, WILSON A.P. . Automation system for quality control in manufacture of iodine-125 sealed sources used in brachytherapy. In: INTERNATIONAL CONFERENCE ON DEVELOPMENTS AND APPLICATIONS OF NUCLEAR TECHNOLOGIES, September 11-14, 2011, Krakow, Poland. Abstract... 2011. p. 122-122.

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  • IPEN-DOC 15341

    MESQUITA, CARLOS H. de ; VASQUEZ, PABLO A.S ; PEREIRA, JOAO C.S. de M. ; MARTINS, JOAO F.T. ; CALVO, WILSON A.P. ; HAMADA, MARGARIDA M. . Development of a gamma ray computed tomography technique for random packed columns analysis. In: REUNIAO DE TRABALHO SOBRE FISICA NUCLEAR NO BRASIL, 31., 8-12 de setembro, 2008, Marisias, SP. 2008.

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  • IPEN-DOC 28643

    GONCALVES, J.A.C. ; SOMESSARI, E.S.R. ; NAPOLITANO, C.M. ; SOMESSARI, S.L. ; BUENO, C.C. . Transit dose measurements using alanine and diode-based dosimeters. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... 2021.

    Palavras-Chave: radiation doses; accuracy; alanines; dosemeters

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  • IPEN-DOC 28642

    SANTOS, S.C. ; RODRIGUES JUNIOR, O. ; CAMPOS, L.L. . Synthesis of thulium-yttria nanoparticles with EPR response. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... 2021.

    Abstract: Introduction: High dose dosimetry demands a continuous effort towards the development of new materials with the aim to guarantee assurance of activities in which ionizing radiation is used. The present work reports a hydrothermal synthesis based on a relative low temperature and pressure to form thulium-yttria nanoparticles with electron paramagnetic resonance response. Material and method: Thulium-yttria nanoparticles (Tm:Y2O3) prepared with 0.1at.%Tm (atomic percentage, at.%) were synthesized by an eco-friendly hydrothermal process as reported in previous study[1]. The nanoparticles were characterized by Photon Correlation Spectroscopy (PCS), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Electron Paramagnetic Resonance (EPR). Results: According to results, the hydrothermal method provided thulium-yttria nanoparticles with cubic C-type structure, mean particle size (d50) less than 90nm (Fig.1), and EPR response. The EPR spectra of powders exhibited two resonance peaks p1 and p2 recorded at 350 and 160mT, respectively (Fig.2). Conclusions: The enhancement of the EPR response of yttria by the use of thulium as a dopant provide meaningful parameters to advance in the formation of new rare earth based materials for radiation dosimetry.

    Palavras-Chave: hydrothermal synthesis; temperature range 0065-0273 k; pressure dependence; thulium; yttrium; nanoparticles

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  • IPEN-DOC 28641

    ALMEIDA, S.B. ; CUNHA, A.P.V.; SAMPAIO, C.C.; MENEGUSSI, G.; CAMPOS, L.L. . Small fields dosimetry employing thermoluminescent dosimeters in the clinical aplication of photon beams. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... 2021.

    Abstract: Introduction: In radiotherapy, the new techniques have some difficulties such as: beam dosimetry, geo- metric characterization and the use of small radiation fields(1). In some cases, the fields sizes are reduced due to the very small lesions, the simulations of the treat- ment in the planning have a very important role, there- fore, they must be provided with data referring to these small fields. Dosimetry becomes quite complex, as the precision becomes quite contestable, especially when small fields are being used in low density regions(2). Due to the absence of lateral electronic balance, de- termining the dose in the target volume in small field cases is quite difficult. Another problem for this type of dosimetry is the sharp dose gradient at the edges of the field. However, this fact requires that the choice of the radiation detector must be of a relevant size in the dosimetry of small fields, taking into account some parameters such as: high spatial resolution, density equivalent to water, linearity, reproducibility, regard- less of energy and rate of dose(3). Material and method: For this analysis LiF:Mg;Ti (3,15 mm in diameter, 0,9 mm in thickness) and μLiF:Mg;Ti (1 mm x 1 mm) dosimeters produced by Harshaw were used. The irradiation system was the Varian Clinac 6 EX with photon energies of 6MV, with the collimator Multi-leaf Brainlab M3 belonging to the Hospital das Clínicas de São Paulo - HC. In addition, for measurements solid water plates (SW) of 30x30x1cm³ dimension were used. The studied field sizes were 9,8x9,8cm2, 5x5cm2, 4x4cm2, 3x3cm2, 2x2cm2, 1x1cm2 and 05x05 cm2. . Results: The dosimeters were selected with TL sensitivity between ±3%. The TL response presented non-significant variation. The dose response curves to photon beams of 6MV presented a linear behavior in the dose range studied (2Gy to 10Gy). Results obtained in simulated irradiations demonstrated the viability of using μLiF:Mg;Ti as dosimeter to dose evaluation of small photon fields with relatively low uncertainties for this type of application. Table 1 presents the result of TL response of the dosimeters for the studied fields. Conclusions: The dosimetry of small fields is very complex and difficult due to the dimensions of the fields, however the LiF:Mg;Ti and μLiF dosimeters demonstrated an excellent viability for this type of application due to their dimensions being minimal and showing uncertainties below 3%.

    Palavras-Chave: radiotherapy; dosimetry; thermoluminescent dosemeters; radiation doses; photon beams

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  • IPEN-DOC 28640

    OLIVEIRA, L.N. ; NASCIMENTO, E.O.; ANTONIO, P.L. ; CALDAS, L.V.E. . Plastic bottle caps as radiation detectors for high gamma radiation doses. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... 2021.

    Abstract: Introduction: Plastic detectors represent an important role in radiation dosimetry [1]. They have been used in a variety of applications, such as portal monitors, and for solar, cosmic, UV, thermal and gamma radiations. Dosimetric evaluation is indicated for material characterization seeking to identify possible applications; proper preprocessing techniques are critical features of this process. This work aimed to determine the linearity response of plastic samples exposed to gamma radiation, using the Fourier Transform Infrared (FTIR) measurements technique. Material and method: Plastic bottle caps were used as sample detectors. They were composed of a hollow cylindrical shape with a 14 mm radius, 0.05 mm thickness, 28 mm height and 3.1 g mass, and they were made of polyethylene (F217). These samples were irradiated in triplicates, with absorbed doses of 0.01 kGy, 0.05 kGy, 0.10 kGy, 0.25 kGy, 0.50 kGy, 1.0 kGy, 5.0 kGy and 10.0 kGy using a 60Co Gamma Cell-220 system (dose rate of 1.089 kGy/h at the Radiation Technology Center of IPEN). Afterwards, each sample absorbance spectrum was acquired on a Fourier Transform Infrared (FTIR) Spectrometer (Frontier/Perkin Elmer) from 400 cm-1 to 4000 cm-1, with 1 cm-1 spectral resolution. The preprocessing was performed in the raw data composed by the broadband source interferogram with a +/- 0.04 cm-1 (2σ) precision for each absorbed dose profile. Subsequently, applying the Fast Fourier Transform (FFT), FTIR was generated. Then, the derivates in the frequency (wavenumber) space were calculated seeking to assess high-order effects. The complex FFT coefficients were explicitly obtained for peak regions, which provided localized information regarding the spectrum approximate shape from the FTIR evaluations to obtain linearity estimatives. The resulting FTIR spectra for each peak was to numerical differentiation at the 1st, 2nd and 3 rd orders (D1, D2 and D3, respectively). The derivates obtained were useful in achieving the spectra shapes and the linearity of response. Results: Figure 1 presents the results after the application of the PCR method: Predicted absorbed dose versus absorbed dose, for: I, II and III regions (from spectrum). The results of the PCR method are the maximum values for linearity, 1.000 for all regions. This result demonstrates that the PCR method is more robust than the linear method, and the preprocessing via PCA provides the information pertinent to the evaluated plastic detector. Conclusion: The results on linearity of response show that plastic bottle caps represent potential radiation detectors for high gamma radiation doses.

    Palavras-Chave: plastics; radiation doses; fourier transformation; gamma radiation

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  • IPEN-DOC 28639

    CARIBE, P.R.R.V.; BONIFACIO, D.A.B. ; CORDEIRO, L.P.; SILVA, A.M.M. da. Influence of BPL-based reconstruction algorithm on image quality for quantitative 90Y-PET imaging. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... 2021.

    Abstract: Introduction: PET/CT technology and image reconstruction algorithms are constantly being improved. This leads to changes in the resulting images which need to be tested and clinically validated. This study evaluated the performance and clinical use of the Bayesian Penalized-Likelihood (BPL) reconstruction algorithm on the state-of-the-art SiPM-based PET/CT for quantitative 90Y-PET imaging. Method: An image quality (IQ) phantom with an 8:1 hot sphere-to-background ratio was scanned on a GE Discovery MI 3-rings PET/CT system during a single bed scan. 90Y acquisition time was 14h and 20 min (representative for clinical count statistics) for an activity concentration of 218 kBq/ml. Reconstructions were performed using: 3-iterations OSEM algorithm with 16 subsets and Gaussian post-filter FWHM ranging from 4.5 to 10 mm; BPL-based algorithm employing a block sequential regularized expectation maximization (BSREM) with Beta parameter varying from 300 to 3000. Time-of-flight and point-spread function modellings were included in all reconstructions. Contrast recovery (CR), background noise levels (coefficient of variation, COV), contrast-to-noise ratio (CNR) and metabolic tumour volume (MTV) were compared to investigate whether the BSREM reconstruction algorithm leads to an improvement in clinical image quality using 90Y. Results: The results for CR versus background COV of the IQ phantom are shown in Fig. 1. All plots show a similar trend: CRs values were as expected with higher CRs for lower β and post-filter FWHM values. The Contrast- to-noise ratio was significantly better in BSREM reconstructions when compared with OSEM in phantom studies. In terms of CR mapping, a BSREM β of 1000 corresponded to 5-6 mm post-filter for TOF-OSEM. Regarding noise characteristics of the 14h data, BSREM outperformed TOF-OSEM reconstructions in terms of noise levels with a 2-3 times lower background COV and improved SUVmean and MATV values for all spheres sizes. Lowering the counts for 20 min data, BSREM noise reduction can be controlled by increasing the β- parameter, but caution should be taken to avoid losing CR information. An optimal range of 1500-3000 β values, can provide a compromise between noise and CR at clinical count statistics. Conclusions: Based on a quantitative phantom study, the BPL-based reconstruction algorithm improves image quality and allows better noise characteristics for 90Y acquisitions when compared to OSEM reconstructions. BSREM reconstructions substantially improved contrast-to-noise ratio and MATVvalues for longer 90Y measurements with better count statistics. For clinically relevant count statistics, BSREM with β values lower than 500 had a limited impact on noise levels of 90Y-PET. The potential improvements of BPL applied to dosimetry calculations are currently being investigated to determine if BSREM can be used to avoids accuracy degradation in the absorbed dose distribution aiming at patient comfort.

    Palavras-Chave: images; positron computed tomography; yttrium 90; algorithms

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  • IPEN-DOC 28638

    CAMARGO, F. ; PASCOALINO, K. ; GONCALVES, J.A.C. ; BUENO, C.C. . Evaluation of a diffused oxygenated float zone (DOFZ) diode response as a high-dose dosimeter. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... 2021.

    Palavras-Chave: dosemeters; radiation doses; radiation effects; decay

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  • IPEN-DOC 28637

    OLIVEIRA, L.N. ; NASCIMENTO, E.O.; ANTONIO, P.L. ; CALDAS, L.V.E. . Ethylene-vinyl acetate detector exposed to gamma radiation and evaluated via principal component regression. In: LATIN-AMERICAN CONGRESS ON SOLID STATE DOSIMETRY AND RADIATION MEASUREMENTS, 1st, September 13-17, 2021, Online. Resumo expandido... 2021.

    Abstract: Introduction: Applications of ethylene-vinyl acetate (EVA) have been reported in radiation physics research, such as in electron beam irradiations, UV measurements and microwave irradiations. Gamma radiation is well known and presents several applications for radiation dosimetry [1]. The evaluation of EVA and other dosimeters can be undertaken by the Fourier Transform Infrared (FTIR) spectrophotometry technique. The goal of this work was to investigate the effect of gamma radiation in green, white and black EVA dosimeter samples for their sensitivity and linearity response, using the PCR method, and evaluated with the FTIR spectrophotometry technique. Material and method: The EVA samples had dimensions of 0.5 x 0.5 x 0.1 cm3, in colors green, white and black. These samples were irradiated in triplicates, with absorbed doses of 0.01 kGy, 0.05 kGy, 0.10 kGy, 0.25 kGy, 0.50 kGy, 1.0 kGy, 5.0 kGy and 10.0 kGy using a 60Co Gamma Cell-220 system (dose rate of 1.089 kGy/h of the Radiation Technology Center of IPEN); afterwards, the absorbance spectrum of each sample was acquired on a Fourier Transform Infrared (FTIR) spectrometer (Frontier/Perkin Elmer) from 400 cm-1 to 4000 cm-1, with 1 cm-1 spectral resolution. The linearity of response was evaluated using the Pearson correlation coefficient (R2). The sensitivity was set as the linear coefficient from a simple linear regression that was fitted using the Ordinary Least Squares Method between the absorbed doses and absorbance values for each wavenumber in the spectra for all colors of EVA samples. The PCR method combines all spectra from absorbance measurements into a single matrix, called here as Xnm, where n is the absorbed doses that varied discreetly from n = 1 up to 8, matching the absorbed doses of 0.01 kGy, 0.05 kGy, 0.10 kGy, 0.25 kGy, 0.50 kGy, 1.0 kGy, 5.0 kGy and 10.0 kGy, m is the spectral resolution index, from m = 1 up to 3600, equivalent to the range from 400 cm-1 to 4000 cm-1. Results: Predicted absorbed dose versus absorbed dose data are shown in Figure 1, for the PCR method, for EVA samples of all colors. The R2 obtained was 1.000 for the PCR method. It can be inferred that these methods are a good alternative, in the applications that require assessing linearity response in dosimetry, since the measurements from each kind of sample may be transformed in linear results. Consequently, these methods can be associated with other characteristics from radiation dosimetry as: reproducibility, fading, spatial resolution and others. Conclusion: EVA samples can be considered as a promising material for measurements of high doses of gamma radiation.

    Palavras-Chave: vinyl acetate; ethylene; polymerase chain reaction; electron beams

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  • IPEN-DOC 28636

    TRICARICO, JULIANA M. ; SOUZA, CARLA D. de . Avaliação em pacientes da radioterapia oncológica em contato direto e não direto com intervenções durante o curso do tratamento: cartilha educativa para pacientes e profissionais da saúde na área de radioterapia com foco em garantir a completude do tratamento. In: WORKSHOP DO MESTRADO PROFISSIONAL EM TECNOLOGIA DAS RADIAÇÕES EM CIÊNCIAS DA SAÚDE, 3., 8 de dezembro, 2021, São Paulo, SP. Resumo... 2021.

    Abstract: Ao decorrer do tratamento de radioterapia oncológica os pacientes sofrem não somente com as dores físicas mas também com o estigma social que é causado por pressão psicológica de estar acometido com uma doença em que a sociedade chama de “incurável‟. Os profissionais da saúde tem um papel fundamental nesse momento no sentido de ouvir e respeitar as necessidades dos pacientes. O detrimento do estado emocional do paciente pode levar a perda de sessões, atrasos e consequentemente prejudicar o resultado final. Este trabalho tem como objetivo a educação de pacientes e profissionais da saúde, com o objetivo de aumentar a completude dos tratamentos radioterápicos. Isso será atingido por meio de 2 cartilhas contendo informalções que sejam claras e bem discutidas. Informações levadas corretamente através cartilhas e métodos educacionais voltados para a assistencia no campo do paciente oncológico e o seu vinculo de ligação com os profissionais de saúde, não somente educa, mas também gera sensação de segurança e qualidade que contribuem para a completude do tratamento. Embora a maioria das organizações institucionais sejam burocraticas e nem sempre preparam seus profissionais para a capacitação de educação continuada por meio de assitencia com foco na humanização e cuidado centrado no setor da radioterapia, é grande importancia que esse cenario seja olhado atraves de uma nova perspectiva, atraves de mais atenção e capacitação das equipes multi-disciplinares atraves de novas formalizações de planos institucionais que busquem visar e proporcionar para seus pacientes não somente um tratamento, mas também uma contribuição ainda mais valiosa, educando também seus pacientes, para que saibam a finalidade do tratamento, seus beneficios, como lidar com o enfrentaneto da doença e contar com uma rede de apoio disposta a ouvi-los através de cuidado e atenção. As cartilhas serão disponibilizadas gratuitamente em site próprio. Os temas utilizados são: Para Profissionais da Saúde - como o profissional em radioterapia devem se portar dentro setor; de que forma os profissionais em radioterapia devem abordar e auxiliar os pacientes; qual a rotina básica de tratamento no setor de radioterapia; como o profissional da radioterapia devem lidar com uma rotina agitada dentro do setor; quais ajudas os profissionais podem ter dentro ou fora de suas instituições em casos de exaustão; Para o paciente - O que é a radiação; o que radiação faz; o que é a radioterapia; qual a rotina da radioterapia para os pacientes; o que os pacientes podem esperar desse tratamento; quais ajudas os pacientes podem ter além do tratamento.

    Palavras-Chave: neoplasms; radiotherapy; human factors; personnel; health services; therapy

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  • IPEN-DOC 28635

    MARTINS, TAINA M.T.M. ; SOUZA, CARLA D. de. Perfil epidemiológico de caso de câncer de próstata em centro de referência no estado do Ceará entre o período de 2014 a 2019. In: WORKSHOP DO MESTRADO PROFISSIONAL EM TECNOLOGIA DAS RADIAÇÕES EM CIÊNCIAS DA SAÚDE, 3., 8 de dezembro, 2021, São Paulo, SP. Resumo... 2021.

    Abstract: No Brasil, o câncer de próstata é o segundo tipo de câncer mais comum entre os homens. Estima-se que no ano de 2020 ocorreram 65.840 novos casos da doença. Durante a campanha do Novembro Azul, o Ministério da Saúde e o Instituto Nacional do Câncer (INCA) desempenham um papel de suma importância para quebrar preconceitos e paradigmas entre os homens, fazendo com que haja uma busca por informações sobre prevenção e tratamento da doença. Este trabalho tem como objetivo fazer uma análise do perfil epidemiológico para câncer de próstata entre o período de 2014 a 2019, utilizando dados do Centro Regional Integrado de Oncologia – CRIO, localizado no Estado do Ceará. Para isso, foi feito uma revisão dos prontuários dos pacientes. Correlações foram criadas a partir do perfil clinico, social, regional e econômico; tipos e justificativas dos tratamentos indicados; fatores de risco associados ao câncer; e correlacionar a incidência com a região do acometido. Foi usado software Jamovi para fazer a análise de correlação de Spearman e Qui-quadrado. A idade média dos pacientes encontrada na amostra desta pesquisa foi de 71,3 anos de idade, a mínima foi de 44 anos e a máxima 96 anos. A análise da escolaridade revelou que 21,5 % dos pacientes são analfabetos e outros 63,5 % possuem apenas o ensino fundamental. A Grande Fortaleza é a região que detém o maior número de pacientes, 52,5 % e o estadiamento que acomete a maioria dos pacientes é o estágio IIB, seguido do III e IV. As principais modalidades de tratamento inicial foram a radioterapia externa, quimioterapia e hormonioterapia.

    Palavras-Chave: neoplasms; prostate; epidemiology; human populations; statistical data; patients

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  • IPEN-DOC 28634

    FREITAS, G.R. ; SOUZA, C.D. de . Metodologia de gestão da informação no controle de exposição em exames de tomografia computadorizada. In: WORKSHOP DO MESTRADO PROFISSIONAL EM TECNOLOGIA DAS RADIAÇÕES EM CIÊNCIAS DA SAÚDE, 3., 8 de dezembro, 2021, São Paulo, SP. Resumo... 2021.

    Abstract: Muitos hospitais brasileiros, a tomografia computadorizada (TC) é o equipamento utilizado para diagnóstico por imagem com maior poder de ionização. Sistemas para monitoramento e gerenciamento de informações não são obrigatórios e o alto valor monetário para aquisição de ‘softwares’ e treinamento faz com que a dose recebida pelo paciente não seja investigada na maioria das vezes. Com isso, existe uma maior probabilidade de exposições desnecessárias ou até proporcionar danos decorrente de exposições a radiação ionizante (STRAUSS et al., 2019). Esses danos podem ocorrer por causa de exames realizados fora de protocolo, mal indicados, repetição em intervalos curtos de tempo e falhas operacionais em decorrência imperícia, falta de atualização e treinamento dos profissionais envolvidos. Organizações internacionais como Image Gently e Latin Safe, promovem todo ano campanhas de conscientização para redução e controle da dose de exposição de pacientes submetidos a exames de diagnóstico por imagem que utilizam radiação ionizante, sendo o controle e/ou monitoramento um dos pilares para prevenção e redução da exposição de pacientes a radiação ionizante para fins médicos. O presente trabalho desenvolveu uma metodologia de baixo custo, utilizando ferramentas gratuitas para armazenamento e avaliação dos DICOM-Structured Report (DICOM-SR) e interpretação desses dados, podendo se tornar um recurso economicamente viável para todos os serviços de diagnóstico por imagem do Sistema Único de Saúde (SUS). Foram analisados 13734 exames de 9911 pacientes no período de setembro de 2019 a agosto de 2021, divididos em grupos de acordo com sua faixa etária. O programa foi utilizado especialmente para otimização do protocolo de TC de Crânio, o que proporcionou uma redução de 11,7% no primeiro ano de treinamento. O novo sistema proporciona gratuitamente e de maneira simples o monitoramento da quantidade de tomografias e da dose recebida em comparação com os protocolos que, por sua vez, resultarão em recomendações clínicas de melhora de procedimentos e treinamentos.

    Palavras-Chave: computerized tomography; knowledge management; dosimetry; dose limits

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  • IPEN-DOC 28628

    FREIRE, RENAN P. ; SILVA, FELIPE D. ; VITALE, PHELIPE; TODESCHINI, IRIS; MENEZES, FILIPE ; OLIVEIRA, JOAO E. de ; OLIVEIRA, MONA das N.; SOARES, CARLOS R.J. . SARS-CoV-2 Spike (S) glycoprotein expression, purification and characterization in suspension human embryonic kidney cells 293. In: PROTEIN EXPRESSION IN ANIMAL CELLS CONFERENCE, 15th, September 13-16, 2021, Online. Abstract... 2021.

    Abstract: SARS-CoV-2 is a zoonotic virus RNA positive, which became responsible to be the largest sanitary crisis faced by humanity: Coronavirus disease 2019 (COVID-19). Some symptoms include major sneeze conditions, who could evolve to severe acute respiratory syndrome, and in some cases, to death. Techniques for accurate detection of this virus are essential to promote an accurate diagnosis of infected patients. SARS-CoV-2 has several targets with clinical interest; although, the focuses is on Spike (S), a homotrimer glycoprotein, that interacts with angiotensin converting enzyme receptor (ACE2), developing the infection in host cells. Thus, we recognize that the demand for the glycoprotein S is necessary, requiring large amounts with high purity level. The current work has the main objective the transient expression of SARS-CoV-2 S protein into suspension human embryonic kidney cells 293 (HEK293), purification and characterization, to use it as a template for discovering new molecular markers. SARSCoV- 2 S modified protein cDNA was inserted into pαH plasmid, amplified, and purified. For transient recombinant protein expression, 7.5 x 107 HEK293 cells (Expi293FTM cells) was seeded in 27 mL Expi293™ culture Medium. The transfection was carried out with a cationic lipid ExpiFectamine™ and 30 μg of plasmid, mixed with 3 mL Opti-Mem® culture medium. Cell culture was maintained for seven days in 125 mL vent cap Erlenmeyer, 32 ºC, 8% CO2, under 125 rpm orbital shaker rotation. 10 mL aliquots were collected on four- and seven-day post transfection, stored at -80 ºC. Physical-chemical and biological characterizations were determined by SDS-PAGE, ELISA, and Western Blotting. Purification from 40 mL of conditioned medium was carried out in two steps: Strep-Tag affinity column, followed by a size exclusion Superose® 6 (10/300), 5.0 mg of oligomeric recombinant protein with 95% purity was obtained. We believe that this process can be easily adapted to different volumes, being very useful for obtaining, in a short time, enough pure and immunological active SARS-CoV-2 S for further studies and applications, such as, cryogenic electron microscopy, mass spectroscopy, N-glycan structures, antibody production and immunologic assays development.

    Palavras-Chave: coronaviruses; glycoproteins; kidneys; embryonic cells; diagnostic techniques

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  • IPEN-DOC 28598

    LIMA, MAYELLE M.P. ; NASCIMENTO, PAMELA F. do ; NASCIMENTO, ANA C.G. ; VIEIRA, DANIEL P. . A simple and quick method to generate in vitro tridimensional tumor bodies from a human breast adenocarcinoma (MCF7) using magnetic aggregation technique. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 382-382.

    Abstract: Tumor physiology studies have to rely on efficient and representative models, as animal-based or in vitro tridimensional cell constructs. The work used magnetite (Fe3O4) nanoparticles produced by electron-beam induced chemical reduction to give cells the ability to form aggregates when submitted to a magnetic field, and thus to produce micro tumors in vitro. The work aimed to produce human breast adenocarcinoma mini tumors (BAMT's) in vitro. Paramagnetic iron oxide nanoparticles (PION’s) were synthesized through electron-beam induced Fe3+ reduction and subsequent coprecipitation. Due to its poly-L-lysine coating, PION’s were adsorbed on cell membranes of MCF7 (human breast adenocarcinoma). Cells were seeded in 24-well cell culture plates pre-treated overnight with Pluronic® F-127 to prevent cell adhesion and kept in culture conditions under magnetic fields for at least 6 days. BAMT's were differentially stained with Hoescht 33342 and ethidium bromide and imaged by wide-field fluorescence microscopy. BAMT's appeared as integer and well-defined cellular aggregates, with sparse dead cells stained by ethidium bromide. These structures can be further used for in vitro tumor studies, as BAMT’s are supposed to be more reliable models than monolayer cultures. Treatment of wells with poloxamer caused a mild to moderated cell-repellent effect, similar to those found in commercially available products, only by a fraction of the cost. The experiments succesfully produced mini tumors prone to be used in in vitro studies.

    Palavras-Chave: carcinomas; mammary glands; nanoparticles; iron oxides

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  • IPEN-DOC 28597

    NASCIMENTO, ANA C.G. ; GALISTEO JUNIOR, ANDRES J.; SILVA, GIOVANA D. da ; ROCHA, LEONARDO W.P. de S. ; VIEIRA, DANIEL P. . Effective methodology for maintaining Toxoplasma gondii in vitro using paramagnetic iron nanoparticles to support three-dimensional cell culture. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 377-377.

    Abstract: Toxoplasma gondii is a protozoan parasite that infects approximately one billion people worldwide. Upon infection, the host may die due to latent infection or presence with chronic cysts in brain, retina or muscle tissue. Humans can become infected consuming water or foods contaminated with oocysts or eating undercooked meat. Its virulent form is difficult to replicate in vitro, requiring additional steps using experimental animals. The use of nanotechnology can contribute to this in vitro production, through the three-dimensional cultivation of mouse fibroblast cells (NIH/3T3 ATCC® CRL-1658™) and nanoparticles synthesized with radiation. The objective of this work was to demonstrate the three-dimensional culture of fibroblast cells aggregated to nanoparticles for inoculation the T. gondii. This methodology was created to facilitate parasite management and replication. For the production of nanoparticles, the work used concentrations of iron sulfate II heptahydrate (Fe2SO4.7H2O, CAS 7782-63-0) and glycine (NH2CH2COOH, CAS 56-40-6) diluted in ultrapure water free of O2 at pH 12. This solution was irradiated by electron beam of the IPEN / CNEN-SP Radiation Technology Center in doses of at least 15 and at most 30kGy. Paramagnetic iron oxide nanoparticles (PION’s) were then adsorbed on cell membranes, and cells were kept together by a magnetic field. Structured spheroids (4 day of culture) were infected with 106 parasites (RH strain) and the infection was evaluated by transmission electron microscopy. Tachyzoites were found inside 3T3 cells, assuring that the spheroid can be a suitable culture substrate to T. gondii in vitro propagation. A three-dimensional methodology for in vitro cultivation of the parasite is perhaps the key for applications in the study of toxoplasmosis, as it has a fast, cheap, efficient production (yield and reduction of contamination).

    Palavras-Chave: protozoa; nanoparticles; fibroblasts; cell proliferation; in vitro

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  • IPEN-DOC 28596

    SEPULVEDA, ANDERSON F.; FRANCO, MARGARETH ; YOKAICHIYA, FABIANO; ARAUJO, DANIELE de. POLYana: a new software for rheological study of polymeric colloidal materials. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 374-374.

    Abstract: POLYAna is a new executable software developed by SISLIBIO group for rheological analysis of hydrogel and organogel systems and other colloidal materials (nanoparticles and micelles). The software development aims to facilitate the analysis of rheology data associated to both temperature- and frequency-dependent analysis, viscosity and curve flow profiles. The software development aims to facilitate the analysis of rheology data associated to both temperature- and frequency-dependent analysis, viscosity and curve flow profiles. From raw data, several models are applied like power-law model for frequency response and curve flow, Boltzmann law to calculate gelation temperature and viscosity response under temperature, Maxwell model to study interchain relationships in addition to other models such as Bingham model, Cross model, and Herschel-Bulkley are also available. POLYana outputs calculates rheological parameters like consistency, adhesion, hysteresis, flow index, G’/G’’ ratio. To validate results obtained from POLYana, same data were analyzed by applying other programs and same mathematical models. In this sense, rheological analysis of Poloxamer 407 in water solution (15 %) were performed: from temperature-dependent G’ and G’’ analysis were obtained gelation temperature of 45.46 ± 0.02 °C, η_0 = 0.08 ± 0.03 mPa*s, η_max = (32.44 ± 0.17) mPa*s and dη/dT = (1.27 ± 0.02) mPa*s/°C by fitting Boltzmann law (R2 = 0.998), which are similar to results obtained by others softwares and found in literature. From temperature-dependent G’ and G’’ analysis, it gets adhesion value of (1647.15 ± 18.01) mPa*sn calculated from power-law model (R2 = 0.869), also similar to PRISM results. Also, other Poloxamer concentrations and hydrogels types have been evaluated, showing close numbers to that previously reported. In order to stablish structural relationships, one of POLYana tools is also to analyze small-angle neutron scattering (SANS) and develop Monte Carlo simulation for SANS and rheological analysis, simultaneously.

    Palavras-Chave: programming; data analysis; rheology; micellar systems; colloids

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  • IPEN-DOC 28595

    SILVA, CAMILA R. ; PINTO, MAYARA S. ; RIBEIRO, MARTHA S. . Photodynamic therapy associated with ionizing radiation in the treatment of triple-negative breast cancer cells. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 258-258.

    Abstract: Breast cancer is the most common cancer for women worldwide. According to the World Health Organization, it is considered the 5 th leading cause of death from cancer. Triple-negative breast cancer (TNBC) is a subtype of this disease that represents around 20% of all invasive breast cancer, whose main characteristics are resistance to conventional treatments, such as exposure to ionizing radiation (IR). On the order hand, the photodynamic therapy (PDT) using porphyrins and their derivatives has been described in the literature as a potential therapy against cancer. Thus, our goal in this work was to associate PDT and IR in the treatment of TNBC. MDA-MB-231 cells at a concentration of 2x104 cells were submitted to PDT using TMPyP porphyrin (30 μM) and a red light (660 ±11 nm) with fluences of the 23 and 57.5 J/cm 2 (57.3 mW/cm 2). Immediately post-PDT, cells were divided into groups: non-treated (control), only IR and PDT associated with IR (PDT57+IR and PDT23+IR) and then, exposed to IR with a dose of 2.5 Gy. Past 24-h of the PDT-session, the cell viability, clonogenicity and total glutathione were verified. Cells exposed to IR not presented statistically significance difference compared to the control group. However, treated groups showed around 38% lower cell viability in relation to the control and IR groups. For the clonogenic assay a reduction of the approximately 65% was observed between IR and treated groups. Regarding to the total glutathione, all groups showed an increase when compared to control group. Nonetheless, no were identified differences between IR and treated groups. Taken together, our results indicate that PDT associate with IR may be an ally in TNBC treatment.

    Palavras-Chave: neoplasms; mammary glands; therapy; radiotherapy; combined therapy

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  • IPEN-DOC 28594

    PINTO, MAYARA S. ; SILVA, CAMILA R. ; SALVEGO, CAMILA de A. ; RIBEIRO, MARTHA S. . Red LED irradiation impacts the cytotoxic response of murine breast cancer cells to ionizing radiation. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 256-256.

    Abstract: Breast cancer is a disease of worldwide importance since it is considered the 5th leading cause of cancer deaths. Triple-negative breast cancer (TNBC) is a molecular subtype that presents resistance to conventional radiotherapy, demanding high doses of ionizing radiation (IR) for a prolonged period of treatment. On the other hand, low-level light irradiation (LLLI) has been studied to sensitize cells before IR exposure. However, the literature is poor regarding the association of both techniques in TNBC cells. Thus, we aimed to assess the effect of LLLI before IR exposure on two TNBC cell lineages. MDA-MB-231 (human TNBC) and 4T1 (murine TNBC) were cultivated, seeded at a density of 2.5 x 105 cells/cm², and maintained in an incubator (37ºC, 5% of CO2) overnight. LLLI was performed with a red LED (λ= 660 ± 11 nm, 38.2 mW/cm²) delivering energies of 1.2 J and 6.0 J. One-h after LLLI, the cells were submitted to both 2.5 and 5.0 Gy doses from a 60CO source. After 24-h, mitochondrial activity (MA) was quantified by MTT assay with n= 9/group. Our data showed that 4T1 cells exposed to LLLI at 1.2 J exhibited higher MA than cells exposed to IR2.5. In contrast, cells exposed to 6 J of LLLI showed lower MA than IR5. Concerning MDA-MB231 cells, no statistically significant differences were noticed among groups regardless of IR and LLLI doses. These findings indicate that LLLI before IR could sensitize only murine breast cancer. Besides, an appropriate combination of IR and LLLI doses seems to play a role to kill TNBC cells.

    Palavras-Chave: radiotherapy; radiobiology; photochemistry; toxicity

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  • IPEN-DOC 28593

    SOUZA, MARESSA D.F. de ; ITRI, ROSANGELA; RIBEIRO, MARTHA S. . Reconstitution of Leishmania plasma membrane to understand the photodynamic effect. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 255-255.

    Abstract: Leishmaniasis is an important neglected disease. Photodynamic therapy (PDT) has been used to fight cutaneous leishmaniasis showing good results. However, PDT mechanisms in Leishmania parasites are not yet completely clarified. In this work, our objective was to develop a protocol to produce giant plasma membrane vesicles (GPMVs) from Leishmania amazonensis promastigotes to understand the mechanisms of action of methylene blue (MB)- mediated PDT on the cell membrane of parasites. For membrane extraction, several techniques were tested. The osmotic shock was the technique that presented the best yield and effectiveness. Phosphate and protein measurements were performed to confirm membrane extraction. For the growth of GPMVs, the best technique was electroforming using different frequencies and voltages in 4 cycles. Reconstituted GPMVs were observed by phasecontrast light microscopy. Subsequently, PDT was applied to GPMVs dispersed in an aqueous solution containing 50 μM MB and we verified the changes in permeability before and after exposure to light. The same process was applied to giant unilamellar vesicles (GUVs) with lipid compositions similar to the parasite membrane. The electroforming technique with the protocol developed in this work made it possible to obtain GPMVs from a promastigote membrane isolate of L. amazonensis. The membrane isolation technique was effective to extract the parasite's membrane while preserving lipids and proteins. In GUVs we observe an increase in the area during PDT in different compositions and loss of contrast. The GPMVs showed a loss of contrast as well as the GUVs but did not show an increase in area. This factor could be explained by the high degree of complexity of the membrane, which contains membrane proteins in addition to containing lipids.

    Palavras-Chave: therapy; photodynamic therapy; protozoa; parasitic diseases; cell membranes

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  • IPEN-DOC 28592

    SOUZA, TIAGO H. dos S.; ANDRADE, CAMILA; CABRAL, FERNANDA ; SARMENTO-NETO, JOSE; REBOUCAS, JULIO; SANTOS, BEATE; RIBEIRO, MARTHA ; FIGUEIREDO, REGINA; FONTES, ADRIANA. Effects of photodynamic inactivation mediated by Zn(II) porphyrin on promastigote and amastigote forms of Leishmania amazonensis. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 250-250.

    Abstract: Photodynamic inactivation (PDI) has been attracting attention as an innovative technology to treat topical diseases, such as cutaneous leishmaniasis (CL) and infections caused by multidrug-resistant microorganisms. Zn(II) mesotetrakis( N-n-hexylpyridinium-2-yl)porphyrin (ZnTnHex-2-PyP4+) is a lipophilic water-soluble Zn(II) porphyrin with improved photophysical properties, high chemical stability, and cationic/amphiphilic character that can enhance its interaction with cells. Thus, this study aimed to investigate the PDI effects mediated by ZnTnHex-2-PyP4+ on Leishmania amazonensis. Confocal fluorescence microscopy was explored to study the interaction of ZnTnHex-2- PyP4+ with promastigotes. The PDI action was analyzed by cell membrane integrity, mitochondrial membrane potential (ΔΨm), and cell morphology. Promastigotes were incubated with ZnTnHex-2-PyP4+ for 5 min at 0.62 and 1.25 μM and irradiated by a LED (410 nm) for 1 or 3 min (2.3 and 3.4 J/cm2, respectively). PDI on amastigotes and the cytotoxicity on macrophages were also analyzed (3.4 J/cm2). Fluorescence microscopy revealed that parasites efficiently uptake ZnTnHex-2-PyP4+ and displayed a punctate labeling pattern along with the cytoplasm. An intense ΔΨm depolarization was also observed, which in association with microscopy results, suggests that ZnTnHex-2- PyP4+ may accumulate in the mitochondrion, or other well-defined structures close to it. Moreover, ZnTnHex-2-PyP4+ at concentration as low as 0.62 μM led to the immediate inactivation of >95% of promastigotes, regardless of the light dose used. Loss of the fusiform shape and plasma membrane wrinkling were also observed. After a single treatment session in amastigotes, PDI led to a reduction of 70% in the infection index. No considerable toxicity was observed on mammalian cells. Thus, PDI of Leishmania parasites showed in vitro efficiency at a submicromolar concentration of ZnTnHex-2-PyP4+, with short pre-incubation and irradiation times. The results encourage further studies in CL pre-clinical assays and PDI of other microorganisms.

    Palavras-Chave: inactivation; skin diseases; porphyrins; mitochondria; cell membranes

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  • IPEN-DOC 28591

    CONTATORI, CAROLINA G. de S. ; PINTO, MAYARA S. ; RIBEIRO, MARTHA S. . Melanoma cell migration in response to red and near-infrared low-level light. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 249-249.

    Abstract: Cell migration plays an important role in tissue formation and cancer progression. In vitro scratch assay has been used for many years to study cell migration to mimic the migration of in vivo cells, and, thus, to evaluate cancer growth. Low-level red and near-infrared light (LLL) can increase normal cell migration. However, the impact of LLL on tumor cells remains unclear. In this work, we aimed to evaluate the effects of a single LLL dose on melanoma cell migration. B16F10 (murine melanoma) cells were cultivated in RPMI medium with 10% of fetal bovine serum until they reached 80% confluency. The cell line was seeded in a 6-well plate at a density of 2x10 5 cells/well in triplicate at two different moments. A wound scratch was performed to disrupt the confluent cell monolayer with a 10 μL pipette tip. Immediately after the injury, the cells were submitted to the LLL at two distinct wavelengths (660 and 780 nm) provided by a LED and a laser, respectively, delivering 3 different energies (1.3, 3.6, and 6 J) at an irradiance of 4.2 mW/cm2. The control group was not irradiated. Cells were photographed immediately and at 3, 12, 24, and 36 h after the scratch. The wound closure was measured using ImageJ software. To evaluate the overall migration, we calculated the areas under the curve for each group. Cells exposed to the red laser at 6 J migrated slower than control. In contrast, LLL at 780 nm promoted faster cell migration when irradiated with 3.6 J. These results suggest that low-level LEDs at 660 nm could prevent melanoma progression in higher energies. However, 780 nm should be avoided at middle energies.

    Palavras-Chave: melanomas; modulation; infrared radiation; light sources; cell proliferation; migration; in vitro

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  • IPEN-DOC 28590

    MITSUTAKE, HERY; SOUZA, ALESSANDRO D. de; YOKAICHIYA, FABIANO; FRANCO, MARGARETH K.K.D. ; CLEMENS, DANIEL; KENT, BEN; BREITKREITZ, MARCIA C.; RIBEIRO, LIGIA N. de M.; PAULA, ENEIDA de; BORDALLO, HELOISA N.. Evaluation of structural changes of benzocaine-loaded, optimized nanostructured lipid carriers using SANS and Raman imaging approaches. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 183-183.

    Abstract: Local anesthetics are substances that reversibly block the nerve-impulse conduction, alleviating pain without loss of consciousness. Benzocaine, a poorly soluble local anesthetic, is an ester of para-aminobenzoic acid. Several strategies of formulations can be used to improve bioavailability and decrease adverse effects of benzocaine. In this study nanostructured lipid carriers (NLC) were employed. These lipid-based drug delivery carriers have a lipid core composed of a blend of solid and liquid lipids, and a shelf of non-ionic surfactant. The main aim of this work was to optimize benzocaine-loaded NLC and to investigate structural changes in these nanoparticles, under different temperatures. The ratio of excipients (cetyl palmitate, Capmul® PG-8 NF and Pluronic®F68) and benzocaine in the NLC was optimized using a 2 3 factorial design with respect to the following parameters: particle size, polydispersity index (PDI) and zeta potentials. The interactions between the factors were found relevant to determine particle size and PDI. Using desirability function, the best formulation conditions were found. Structural changes in optimized NLC were observed with Small-Angle Neutron Scattering (SANS) and Raman imaging, in samples at 27, 37 and 40º C. SANS pointed the formation of lamellar structures inside the NLC, which interlamellar distances increase at higher temperature. Raman imaging showed that the incorporation of P68 and benzocaine in-between the lipids increased at higher temperatures, explaining the changes in Q values (SANS). This work shows how different scattering techniques can provide complementary information and be used together to characterize and understand the physical, chemical, and structural changes on the organization of pharmaceutical carriers in drug delivery system.

    Palavras-Chave: drugs; pharmacology; anesthetics; drug delivery; design; raman spectra

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  • IPEN-DOC 28589

    SANTOS, CAROLINA M. dos ; SAMPAIO, SUELEN de B.; SANTANA, FAGNER ; LEITE, RODRIGO C. ; PRATA, BEATRIZ A. ; AFFONSO, REGINA . A new approach for purification of the catalytic site of the Angiotensin Conversion Enzyme, N domain, mediated by the ELP-Inten system. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 143-143.

    Abstract: Angiotensin-converting enzyme I, ACE, is a key part of the renin-angiotensin system whose main function is to regulate blood pressure and balance of salts in the body. ACE1 has two isoforms, somatic, sACE, and testicular, tACE. sACE possesses two domains, N- C-, with catalytic sites which exhibit 60% sequence identity. These domains differ in terms of chloride-ion activation profiles, rates of peptide hydrolysis and sensitivities to various inhibitors. N-domain has specific action in the hydrolyze of Alzheimer’s diseases beta amyloid bodies and angiotensin 1-7, which active the MAS receptor and triggering anti-thrombotic and anti-inflammatory actions. The objective this work was to obtain catalytic site Ala361 to Gli468 of the N-domain region, csACEN, isolation without chromatographic and denaturant chemical process. For that, a new methodology was used in the expression of the csACEN peptide, in which the peptide was linked to the elastin-like polypeptide, ELP, and Intein, and expressed at 37C. The characterization of catalytic site was made by SDS-PAGE and dot blotting. The culture temperature at 37C significantly increased the expression of the ELP/Intein/csACEN fusion protein. This culture was lysed at a low temperature allowing the fusion protein to become soluble. The precipitation of ELP at high concentrations of ammonium sulfate were obtained in 0.57 M and 0.8 M. Intein autocleavage occurs at acidic pH and it is important to pay attention to: pI 6.65 for csACEN and pI 6.87 for ELPcsACEN, which are very low. The best autocleavage efficiency was with MES and TriHCl buffers, pH 6.3 and 6.8, respectively, in which pure csACEn peptide was obtained. The strategy used to obtain the Ala361 to Gli468 catalytic site in soluble and pure form was obtained with success and the protocol for obtaining similar peptides was established.

    Palavras-Chave: angiotensin; enzymes; inflammation; thrombosis; temperature dependence

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  • IPEN-DOC 28588

    TREMARIN, BEATRIZ; YOKAICHIYA, FABIANO; KELLERMANN, GUINTHER; FRANCO, MARGARETH K.K.D. ; STORSBERG, JOACHIM. Improvement of the methodological strategies to product functionalizes antibodies using Small Angle Neutron Scattering (SANS). In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 138-138.

    Abstract: Antibodies are used by jawed vertebrates for defense against invading pathogens. Usage of those versatile tools in a plethora of settings in clinics and biomedical sciences hinges on functionalization strategies that retain native antibody reactivity. To this date, antibody functionalization is performed by trial and error. We aim to reduce costs by providing general principles to allow the full spectrum of antibody functionalization by correlating functionalized antibody reactivity to cognate antigen by small angle neutron scattering, SANS, measurements and mathematical modeling of antibody and antibody-antigen super-complexes, obtained by titration experiments. For this research we have used for as antibody pure goat anti rabbit immunoglobulin, and for the antigen, pure Horseradish Peroxidase Preliminary results show that the systems (antibody and antibody-antigen complexes) do not change in the range of a temperature related to storage temperature (25º C), body temperature (37º C) and 40º C. These results will give us the pair distribution function of these systems and the results will be viewed in light of published precedence to highlight areas where future effort is needed to refine such versatile tools and improve their production. However, between the antibody and the complexes structure, different conformations were observed. The antibody has a globular structure with a radius of gyration around 33 Å, and the complexes display an elongated cylindrical shape with radius of gyration around 63 Å. This study shows how the scattering techniques (SANS) can provide useful information about the conformation of the antibody and antibody-antigen formation and help to shed light in the understanding the physical, chemical, and structural changes on the organization of these important antibody functionalization for the immunological system.

    Palavras-Chave: neutrons; small angle scattering; antigen-antibody reactions; biophysics

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  • IPEN-DOC 28587

    ZEZELL, DENISE M. . Radiation Technology in Health Sciences at IPEN: a multidisciplinary and interdisciplinary Professional Master Degree. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 105-105.

    Abstract: The Professional Master Program in Radiation Technology in Health Sciences (MP-TRCS) of the Nuclear and Energy Research Institute- IPEN/CNEN is a new program, started in August 2019. It is the only graduation program in the country to offer two nuclear reactors for educational purposes, for the development of dissertations, in addition to providing radiopharmaceuticals production in a nuclear reactor, in linear accelerator for radioisotope production, as well light and lasers applications. In addition to the infrastructure, the program has multidisciplinary training advisors working in an interdisciplinary manner who use their vast experience in radiation applied to medicine to guide students in a productive manner with a high degree of excellence. The MP-TRCS aims to fulfil a growing demand at IPEN/CNEN from professionals working in hospitals and clinics, using ionizing and non-ionizing radiation. These students need a more dynamic course directed to the practical professional activities. We have students from the most diverse areas, such as medical doctors, biomedical doctors working in clinical analyses, radiotherapy physicists, physiotherapists, dentists specializing in imaging diagnosis and laser, among others, participating in the front line, who use radiation or assess its impact on their day-to-day routine. The first students have already begin to present their dissertation. The employability has increased among students enrolled in the program. These professionals bring their experience to the program, which together with IPEN's academic structure and advisors, result in skilled students who are finding numerous career opportunities in the job market.

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  • IPEN-DOC 28586

    VIEIRA, DANIEL P. . Three-dimensional cellular culture system for testing of biological effects of radiations in tumoral and non-tumoral models. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 89-89.

    Abstract: In vitro cell cultures are a well-known controlled test system used to analyze tumor physiologic responses upon negative stimuli. Updated techniques, us-ing three-dimensional organization of cells in cultures, are being increasingly used to this purpose. Research organizations and industry are striving to pro-duce in vitro tumor surrogates that could be better test systems to antitumor agents as new compounds or to study radiation effects on cancers. The presentation will show some techniques currently used to build and maintain these specific cell cultures, and how experiments are evolving towards the production of tumoroids, or tumoral organoids, which will include various cell types and additive manufacturing.

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  • IPEN-DOC 28585

    DEL MASTRO, NELIDA L. ; GERVASONI, J.L.. Women in the nuclear field promoting Latin American integration. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 84-84.

    Abstract: Nuclear energy is used for the generation of electricity, but also for the production of radioisotopes, desalination of sea water and also for the production of hydrogen. Activities in the nuclear field are in the area of science, technology and innovation that has long belonged to an essentially male domain, in which the contributions of women were neglected or underestimated. The central idea for the creation of Women in Nuclear, WiN Global, was to support and encourage women working in nuclear science and technology and encourage the promotion of understanding and knowledge of the benefits of the peaceful use of nuclear energy by the public. WiN Global currently has predominantly female members coming from 129 different countries, belonging to chapters or individually. Today, WiN Global is integrated by 53 WiN Global chapters. Forty-nine countries have their own chapters and there are also regional and international ones. The history of Latin American integration started during the political independence movement of the countries of the New Continent. Since then, up and downs were overcome in order to keep a regional ambiance of good relationship. In the present study, a new form of integration is presented by the efforts of the women working in the nuclear ambit. This important movement involves Latin American WiN chapters (such as WiN Argentina, WiN Brazil, WiN ARCAL) promoting activities for the integration of our region. In order to quantify, to some extent, the participation of Latin American women, this paper presents a survey crossing data of the number of related publications to help to address an objective analysis of the trend of this integration.

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  • IPEN-DOC 28584

    VALLE, MATHEUS del ; SANTOS, MOISES O. dos . Breast tissue diagnosis using artificial intelligence applied to FTIR spectroscopy images. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 42-42.

    Abstract: The estimative of new breast cancer cases was of 2.1 million of new breast cancer cases in 2018, hence being the most incident type of cancer in women. The improvement of its diagnosis has been the aim of many researchers, including vibrational spectroscopy teams. With the advancement of the artificial intelligence, a field of computer science to enhance intelligence into computer systems, specially of the deep learning, big data acquired from spectroscopy image has entered a new era. Therefore, the proposal of this work was to diagnose breast tissue samples as malignant (cancer) or benign (adenosis) using deep learning techniques. Micro-FTIR spectroscopy images were acquired from BR804b human breast tissue microarray (Biomax, USA), resulting in more than 100 thousand spectra for each group. A k-means approach was established to separate spectra into three clusters: tissue, paraffin and slide. A preprocessing step was applied by the following pipeline: outlier removal; biofingerprint truncation; Savitzky–Golay filter to smooth and to obtain the second derivative; extended multiplicative signal correction to correct spectra and remove the paraffin contribution. The deep learning algorithm was built using two-layers of one-dimensional convolutional neural network (CNN) connected to a two-layers (100 and 50 neurons) feedforward network (FFN). Both networks used dropout layers of 50% and rectified linear unit activations. CNN kernel size was set to 5. The output neuron used a sigmoid activation. Adam optimizer was applied to train the networks, using a binary cross-entropy loss to improve the weights. A 4-fold cross-validation of 20 epochs and batch size of 250 was performed. The networks exhibited an accuracy of (97.8 ± 0.4)% during the training stage, and (96.9 ± 0.8)% during the testing stage, demonstrating a generalized classification. Accuracies of almost 100% indicates this approach as a potential technique for the breast diagnosis.

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  • IPEN-DOC 28583

    YOSHIMURA, TANIA M. ; SAUTER, ISMAEL P. ; RIBEIRO, MARTHA S. . Low power light triggers opposite effects on stem cells: influence of the wavelength and culture conditions. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 41-41.

    Abstract: Photobiomodulation (PBM) has been gaining importance in a wide range of medical fields in the past few years, particularly in stem cell-based regenerative medicine. Improving in vitro cell proliferation, differentiation and viability are ways where PBM could play a pivotal role optimizing biotechnological and bioengineering applications. Here we investigated whether different wavelengths (blue, green and red) would promote distinct outcomes in human adipose-derived stem cells (hADSCs) cultured in regular and supplemented media for tenocyte differentiation. MATERIALS AND METHODS. Freshly isolated hADSCs were cultured in a specific stem cell medium (MSCGM, Lonza), DMEM or a tenogenic medium (TEN-M: DMEM supplemented with growth factors and ascorbic acid). Cells were irradiated every 48 h (23.28 mW/cm 2, 17 min 10 s delivering 24 J/cm 2 per session) using a LED irradiator (LEDbox, BioLambda). MTT and crystal violet assays were used to evaluate cell metabolic activity and proliferation. Red wavelength (660 nm) significantly increased metabolic activity after five irradiations, but only for cells cultured in TEN-M. Oppositely, blue (450 nm) and green (520 nm) light decreased both cell proliferation and metabolic rate, with more pronounced effects for blue light in TEN-M. Considering these findings, we examined whether irradiating only the media would generate toxic compounds that could impair cell viability. We therefore assessed reactive oxygen species (ROS) production by p-nitrosodimethylaniline/ histidine assay while irradiating the three different media under the same conditions as mentioned above. Immediately after blue and green light exposure, an increment in ROS production was observed for DMEM and TEN-M, that continuously increased until reaching between 4.5 and 7.1 μM one-hour after irradiation – with higher values for TEN-M exposed to blue light. Since no significant ROS formation was observed following red light exposure, we concluded that medium composition was responsible for the different effects on metabolic activity and proliferation observed after irradiation with different wavelengths.

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  • IPEN-DOC 28582

    RIBEIRO, MARTHA S. . Light-based non-thermal therapy: from basis to clinical applications. In: CONGRESS OF THE INTERNATIONAL UNION FOR PURE APPLIED BIOPHYSICS, 20th; ANNUAL MEETING OF THE BRAZILIAN SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGY, 50th; CONGRESS OF BRAZILIAN BIOPHYSICS SOCIETY, 45th; BRAZILIAN SOCIETY ON NUCLEAR BIOSCIENCES CONGRESS, 13th, October 4-8, 2021, São Paulo, SP. Abstract... São Paulo, SP: Sociedade Brasileira de Bioquímica e Biologia Molecular (SBBq), 2021. p. 39-39.

    Abstract: Light-based non-thermal therapies are evolving as promising non-invasive and cost-effective medical technologies. These therapeutic platforms mainly encompass photobiomodulation (PBM) and photodynamic therapy (PDT), which use visible or near infrared (NIR) light to induce biological responses without any significant heating effects. For PBM, it is most commonly used red or NIR light to optimize light penetration into biological tissues. The photon absorption by natural chromophores at these spectral regions cause photophysical and photochemical reactions inside cells that trigger several biological effects such as to accelerate wound healing, reduce inflammation and relief pain, depending on light parameters and target tissue. On the other hand, PDT makes use of photoactivated drugs, also called as photosensitizers, which absorb light to induce chemical reactions that kill microbial or cancer cells by oxidative stress. Our group have been investigating the mechanisms and several applications of PBM and antimicrobial PDT (APDT) for almost 20 years. In this lecture I will share our experience in the area to discuss how PBM and APDT could be used to revolutionize health care in the photonics era. An integrated perspective from the basic mechanisms, preclinical and clinical trials for both therapies will be presented, including PBM on cancer management and APDT against drug-resistant pathogens. The lecture will also highlight future perspectives.

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  • IPEN-DOC 28578

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de . Some facts about nuclear forces and evidence of their range being longer than people believe. In: INTERNATIONAL CONFERENCE ON CONDENSED MATTER NUCLEAR SCIENCE, 23rd, June 9-11, 2021, Online. Abstract... 2021.

    Abstract: Nuclear forces are believed to have ranges around 2 fermi and beyond that range, only electrostatic force is relevant. Before trying to make theories about the phenomena of nuclear reactions observed in solids, it is important to revise critically the existing experimental literature and nuclear theory to check if current models are coherent and if they could explain the observed phenomena. The first step is to check the current nuclear models, the second is to analyse the neutron cross-section data, the third is to discuss coherence between empirical data and models, the fourth is to identify the order of magnitude of nuclear forces range, the fifth is to revise the full height of Coulomb barrier. It was found one isotope (Gadolinium-157) that can attract a thermal neutron at least at 2781 fermi and repulses neutrons at 179 Fermi. It was also found that the plane projection of volumes where neutrons are directly captured is distinct of the projection of the volume where neutrons are scattered for most isotopes. But Kryptonium, Ruthenium, Xenonium, Iridium, and Mercury elements seem having their scattering volumes covered by the absorption volumes, or not having a scattering volume at all. Ca-44, Ca-48, Ni-64, Se-74, Te-123, Dy-162, Hf-177 and W-186 isotopes seem having a partial screening of their scattering volume by the absorption volume. Resonance capture volumes seem to be independent of direct capture volumes and have interface with scattering volume. Three facts suggest absorption volumes are consequence of nucleons arrangement, assuming an FCC nucleus model. The first is that a single additional neutron may change the order of magnitude of absorption radius (like He-3 to He-4). Second, excited states also change absorption cross-sections, like Na-23 whose first excited state increases absorption cross-section and Cl-37 whose first excited state decreases absorption cross-section. Third, neutron capture resonance depends on existence of an excited state of the compound nucleus (target nucleus plus the neutron) with energy larger than this neutron binding energy. In other words, to have a resonance, the target nucleus needs to have two places available for a neutron, and the energetic distance between them needs to be larger than a minimum (the very neutron binding energy). Compared to Coulomb forces, the nuclear forces attracting neutrons are weak, about 6 orders of magnitude smaller than electrostatic repulsion at mean thermal neutron capture radius.

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  • IPEN-DOC 28577

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de . A survey on the evolution of yearly works on Pd-D, Ti-D and Ni-H systems within cold fusion field. In: INTERNATIONAL CONFERENCE ON CONDENSED MATTER NUCLEAR SCIENCE, 23rd, June 9-11, 2021, Online. Abstract... 2021.

    Abstract: More than 30 years have been passed since Stanley and Pons press conference announcing the discovery of “Cold Fusion”. This work aims at presenting a general view of the evolution of experimental works in the various sub-fields, like Pd-D, Ti-D, Ni-H systems. For each subfield, this work presents the yearly number of successful and unsuccessful works published in conferences or journals. For Pd-D systems, since 1989, the number of positive results (finding some nuclear reactions) is superior to negative results but there is a trend of reduction of yearly works. Ti-D systems follow the same tendency. Ni-H systems, on the other hand, present a rising tendency besides having a higher ratio of successful/unsuccessful experiments. Perhaps the smaller cost of materials and easier replication is being decisive for new research groups starting in the field, besides enterprises starting advertisement of products based on the Ni-H system.

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  • IPEN-DOC 28576

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de . A hypothesis of kinetics and dynamic control of nuclear reactions in solids. In: INTERNATIONAL CONFERENCE ON CONDENSED MATTER NUCLEAR SCIENCE, 23rd, June 9-11, 2021, Online. Abstract... 2021.

    Abstract: Several authors suggested that background noise could influence nuclear reactions in solids, resulting in neutrons or excess heat. Literature shows that repeatability is improving, but the control over the intensity remains out of reach. This work aims at identifying possible causes for intensity variations and proposing solutions to improve controllability. The first step is to search in literature the characteristics of nuclear reactions in solids: input, output, controlling factors and enabling means. The second step is, from solid experimental facts, draw solid conclusions. The third step is developing some assumptions about the phenomenon. For each controlling factor, verify the feasibility of implementation in a heat exchanger with high surface over volume ratio. Finally, present some alternatives of architectures to improve reactions intensity control. A solid conclusion is hot spots come from aneutronic nuclear chain reactions, meaning each energetic charged particle causes the appearance of more than one new charged particle (effective multiplication factor keff>1). Another conclusion is background neutron radiation starts chain reactions and it causes excess heat intensity variations. An assumption is a local keff>1 causes micro explosions terminating the localized reactions because heat propagates faster than the particle population, resulting in low average keff. Therefore, nanoparticles or working temperatures near melting point reduce local keff allowing slow enhancement of particle population up to a level proportional to the background neutrons. A suggestion is to shield the reactors using moderators with neutron absorbers to avoid undesirable power excursions and add a voltage-controlled neutron source to control the excess heat because of the penetrating nature of neutron radiation. Magnetic or electric fields could also help the enhancement of excess heat.

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  • IPEN-DOC 28568

    GERAMI, ADELEH M.; SCHELL, JULIANA; CARBONARI, ARTUR ; COSTA, MESSIAS S.; COSTA, CLEIDILANE; VIEJO, CARLOS D.G.; LORENZ, KATHARINA; PIRES, JULIO; MONTEIRO, JOAO; JOHNSTON, KARL; CORREIA, JOAO M.. Density functional theory study of Cd impurities in molybdenum trioxide. In: ISOLDE WORKSHOP AND USERS MEETING, December 14-16, 2021, Online. Abstract... 2021. p. 27-28.

    Abstract: Transition metal oxides semiconductors (TMOs) are known for their special optical and electrical properties with wide-ranging applications, including gas sensing, storage devices such as Li-ion batteries, solar cells, and catalysts[1,2]. Among different types of TMOs, there is a class of materials that are distinguished by their unique layered structure and multiple oxidation states, such as MoO3, WO3, and V2O5. The molybdenum trioxide (MoO3) is known for its photo-, thermo- and electrochromism, high catalytic activity[3]. The MoO3 has found in different structural phases including the orthorhombic phase, α-MoO3; monoclinic phase, β-MoO3; metastable phase at high-pressure conditions, β′-MoO3; and hexagonal phase, h-MoO3[4]. Among them, the α-MoO3 is the most stable crystal phase and it has a layered structure consisting of van der Waals bonded sheets of distorted edge-sharing Mo−O6 octahedra in which Mo atoms are bounded by three distinct types of oxygen atoms[5]. In this research, the structural properties and hyperfine parameters of 111mCd(111Cd) impurities in α-MoO3 are investigated by first-principle calculations in the framework of density functional theory (DFT). The Perdew–Burke–Ernzerh of generalized gradient approximation (GGA-PBE), and GGA-PBE plus Hubbard-U corrections for onsite Coulomb interactions are used in the DFT calculations. In the calculations performed, the effect of van der Waals forces between layers is employed using the DFT-D3 method[6]. To interpret the experimental results, different configurations around the Cd atom including the different types of oxygen vacancies are simulated. The comparison of experimental data with calculated hyperfine parameters indicates that the Cd atom is predominantly located in the interstitial lattice site of MoO3, and also the oxygen vacancy is most likely to form on the 2-fold coordinated (O2) atoms. The results of this work demonstrate the benefit of first-principle calculations for solving the outstanding questions arising from the experiment.

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  • IPEN-DOC 28567

    BURIMOVA, ANASTASIA ; LEITE NETO, OSMAR F. ; BOSCH-SANTOS, BRIANNA ; CORREA, EDUARDO L. ; PEREIRA, LUCIANO F.D. ; SALES, TATIANE S.N. ; RIBEIRO JUNIOR, IBERE S. ; COSTA, MESSIAS S.; COSTA, CLEIDILANE; DANG, THANH T.; ZYABKIN, DMITRY; VAN STIPHOUT, KOEN K.F.; GERAMI, ADELEH M.; CORREIA, JOAO M.; SCHELL, JULIANA; CARBONARI, ARTUR W. . Cd impurities in Vanadium oxides: a hyperfine interaction investigation using 111mCd nuclei. In: ISOLDE WORKSHOP AND USERS MEETING, December 14-16, 2021, Online. Abstract... 2021. p. 15-16.

    Abstract: The number of metastable phases, the capriciousness at changing external conditions, and lack of accurate description of local behavior already resulted in severe misinterpretation of experimental outcomes for vanadium oxides[1–3]. The scope of already implemented and potential applications of vanadium oxides is, indeed, impressive, particularly as a battery cathode for energy storage[ 4]. Doping is widely exploited as a means of application-oriented tuning of the material properties. The properties of each particular phase may be tuned by doping to satisfy specific requirements and/or improve the functional performance. In the work here reported, electric quadrupole interaction on 111mCd nuclei implanted in vanadium pentaoxide doped with different concentrations of Cd were measured with time-differential perturbed angular correlations (TDPAC). Pure V2O5 as well as doped with 1%, 5%, and 10% of Cd were measured at different temperatures. To correlate the results with the possible formation of different phases and compounds, samples of VO2, CdV2O6, and Cd2V2O7 were also measured. The intention is to provide a comprehensive description, at an atomic level, of the doping effects on the local crystal structure and the electronic structure around the impurity and the consequences on the properties of the host oxides. Preliminary results show that the probability of formation of cadmium vanadates is low but the temperature and atmosphere of measurements have an important effect on the local scale.

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  • IPEN-DOC 28565

    LINS, C. ; MOREIRA, E.G. ; SOUSA, E.P.. Ecotoxicological quality of Caraguatatuba Bay sediment, São Paulo, Brazil. In: SOCIETY OF ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY (SETAC) LATIN AMERICA BIENNIAL MEETING, 14th, September 26-29, 2021, Online. Abstract... Pensacola, FL, USA: Society of Environmental Toxicology and Chemistry (SETAC), 2021. p. 54-54.

    Abstract: Caraguatatuba Bay (-23.66363, -45.43035), at the northern seashore of São Paulo State, Brazil, is exposed to significant sources of marine pollution: domestic effluents and spills of oil and its derivatives. This is due to its proximity to the São Sebastião Channel, where the submarine emissary outfall takes place and where the largest oil transport terminal in Brazil is located. Due to their hydrodynamic characteristics, pollutants tend to deposit in the sediment, impacting the organisms associated with it. These organisms are of great ecological importance, linked to the basis of the food chain and many species are of nutritional and commercial interest. The region remains an important stronghold of artisanal fishermen and mollusk pickers, which raises concerns about the consumption of these organisms by the local population and tourists. The aim of this study was to evaluate the quality of the bay sediment by means of ecotoxicological tests on sediments collected at six points distributed in the bay, in the 2018 winter and in the 2019 summer. Total sediment acute toxicity tests were performed using the amphipod Leptocheirus plumulosus. Samples that presented different results compared to the control sample were only observed in the winter campaign, in three points: Indaiá and Centro Beaches, according to Dunnett's test (p ≤ 0.05) and Indaiá, Centro and Camaroeiro Beaches, according to the t-test (p ≤ 0.05). Sediment samples of these beaches showed adverse effect to the organisms of the assay, being considered toxic. Sediment samples from Porto Novo, Flexeiras and Palmeiras Beaches in winter and all points in the summer campaign did not cause adverse effects to the organisms and were not considered toxic. The three points which samples were considered toxic are on the beaches located from the center to the northern end of the bay where an inlet is formed. The distribution of points with toxicity follows the pattern of particle deposition and approaches the results of sanitary quality of the region according to CETESB, the São Paulo State Environmental Protection Agency.

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  • IPEN-DOC 28564

    TOMINAGA, F. ; LEO, P.; BORRELY, S.I. . Toxicity assessment of acetylsalicylic acid using Saccharomyces cerevisiae. In: SOCIETY OF ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY (SETAC) LATIN AMERICA BIENNIAL MEETING, 14th, September 26-29, 2021, Online. Abstract... Pensacola, FL, USA: Society of Environmental Toxicology and Chemistry (SETAC), 2021. p. 50-50.

    Abstract: Urban and industrial growth has triggered the release of toxic compounds into the environment, causing negative impacts on the population and ecosystems. Among the pollutants, pharmaceuticals have drawn attention due to potential of impacting the environment at ecological relevant concentrations. Aspirin is widely used in human medicine as an analgesic, antipyretic and in actively preventing platelet aggregation, and it is frequently detected in influent samples at relatively high concentrations. The yeast Saccharomyces cerevisiae consists in simple eukaryotic model, widely used for toxicity assessment. The current study aims to evaluate the toxicity of the anti-inflammatory acetylsalicylic acid (aspirin) using viability and conductometric assays. The viability assays were based on the evaluation of the number of viable cells present in a cell suspension after 1 hour exposure, while the conductometric tests were done by monitoring of changes in the specific conductivity of suspensions of S. cerevisiae due to inhibition of fermentation in toxic conditions after 30 minutes of exposure. The viability tests showed no reduction of viability at the evaluated concentrations (up to 100 mg L-1). The conductometric assays demonstrated low sensibility of the yeast to aspirin with EC5030min of 815 mg L-1. The results also indicated that there was no increase in the sensitivity of conductometric assays even at 6 hours of exposure. Furthermore, the acute toxicity data was compared with data obtained from in silico toxicity models (ECOSAR). Toxicity data collated from the software from different trophic levels showed EC5096h, LC5048h and LC96h of 867, 1774 and 777 mg L-1 for green algae, daphnid and fish, respectively, indicating low toxicity of aspirin.

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  • IPEN-DOC 28563

    FERREIRA, LUCAS A. dos S. ; MUCCILLO, ELIANA N. dos S. . Electrical conductivity and grain growth of 12Ce-TZP. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 45-45.

    Abstract: Ceramic materials based on tetragonal zirconia polycrystals (TZP) with yttrium or cerium oxide have been thoroughly studied for a number of technological applications, due to their outstanding thermomechanical properties. In this work, tetragonal zirconia polycrystals containing 12 mol% cerium oxide (12Ce-TZP) were prepared by solid-state reaction using different sintering methods, to evaluate the influence of the final microstructure on the electrical conductivity. High purity zirconium oxide and cerium oxide starting chemicals were weighted in the stoichiometric proportion and ball-milled for 6 h for homogenization. Cylindrical specimens were prepared by pressing followed by sintering. Sintering experiments were carried out by the conventional and the two-stage methods. The mean grain size of specimens sintered by the conventional method achieved approximately 2.4 mm after sintering at 1450 ºC/5 h, whereas those sintered by the two-stage method exhibit less than 1.5 mm even after 10 h at 1350 ºC, in the second stage of sintering. The electrical conductivity determined by impedance spectroscopy shows the usual Arrhenius behavior for both the bulk (or intragrain) and grain boundary (intergrain) conductivities, with activation energies of ~0.97 (bulk) and 1.25 eV (grain boundary). The grain conductivity of specimens sintered by different methods does not depend on the grain size. In contrast, the grain boundary conductivity is higher for specimens sintered by the two-stage method, possibly due to dissolution of minor impurities located at grain boundaries into the bulk, during the long holding times of the two-stage method.

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  • IPEN-DOC 28562

    SILVA, JOSE T. da ; SOUZA, CARLA D. de ; NOGUEIRA, BEATRIZ R. ; ANGELOCCI, LUCAS V. ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Homogeneity evaluation of phosphorus-32 epoxy plaques to be used in the treatment of spinal and intracranial cancer by brachytherapy. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 919-919.

    Abstract: In Brachytherapy, radioactive source is positioned close to the tumor. The most important advantage is that the target region receives most of the dose, protecting the healthy tissues adjacent to the tumor region. In order to use these sources, a high dosimetric uniformity must be achieved, so a homogeneous dose delivery can be delivered to the target. In the present work, the consistency of the epoxy resin plate was evaluated using a methodology developed in the laboratory for the production of radiotherapy sources at IPEN / CNEN - SP. Several tests were carried out to determine the best mold for the source manufacture. It was concluded that polytetrafluoroethylene (PTFE), which is commercially known as teflon, obtained the best result, due to the ease unmold of the source after the resin curing process. The epoxy plaques were produced with resin 2220 and catalyst 3154 (Avipol), at a 2:1 mass ratio. To simulate the radioactive material, hydrochloric acid (HCl) equivalent to 5% of the total mass (resin + catalyst) is added. The epoxy resin cured for 24 h at room temperature. The thickness of the plaques was measured reaching an average value of 0.300 mm ± 0.070. The measurements were made with a micrometer, measuring 10 points of each plaque. The measures of width and length were not performed, as these parameters do not influence the uniformity of the dose. In order for the distribution of phosphorus-32 activity to be stipulated, a Monte Carlo Simulation using the MCNP code was performed. The maximum dose variation along the plaque, considering a totally uniform thickness of 0.300 mm, resulted in <0.5% up to 0.5 cm before the edge. The result of the simulation shows that with a uniformly thick plaque, the dose distribution trend is homogeneous. Based on the results, the epoxy polymer plaques are shown to be viable for use in brachytherapy, and the next step of the work will be the tests with radioactive material.

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  • IPEN-DOC 28561

    TRINDADE, FABIANE J.; DAMASCENO, SERGIO; OTUBO, LARISSA ; SCHMAL, MARTIN; FLORIO, DANIEL Z. de; FONSECA, FABIO C. ; FERLAUTO, ANDRE S.. Lanthanum doped ceria shaped nanostructures for oxidative coupling of methane. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 308-308.

    Abstract: The abundance of natural gas due to the advancements in exploration and extraction technologies has increased the interest in the direct conversion of methane to C2 molecules via oxidative coupling of methane (OCM) reactions [1]. The design of catalysts by tailoring shape and oxygen vacancies has a significant impact on their performance [2]. Within this context, in this work, the fine-tuning of structural defects of ceria rod-like and cube-like shaped nanoparticles were performed via La3+ doping (LaxCe1-xO2-x/2) in molar ratios of x=5-90 mol %. The morphology control was achieved by varying the hydrothermal synthesis temperature from 110 °C to 180 °C. The characterization of LaxCe1-xO2-1/2 catalysts was performed by SEM, HRTEM, XRD, and Raman spectroscopy. The catalytic performance of the new nanomaterials for the OCM reaction was studied at 750 °C with an in-line gas chromatograph. In the LaxCe1-xO2-x/2 nanorods, the fluorite crystalline structure is essentially maintained even for x = 0.6. The Raman spectra analysis indicates that the addition of La3+ leads and increases the formation of different amounts of extrinsic and intrinsic oxygen vacancies. In addition, the catalytic tests for OCM reaction show that the LaxCe1- xO2-1/2 (x=50%) nanorods catalyst have 25% of CH4 conversion and 48% of selectivity for C2 products. The concentration of reactive oxygen species in the LaxCe1-xO2-1/2 (x=50%) nanorods was crucial to improving the conversion rates and selectivity.

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  • IPEN-DOC 28560

    CARVALHO, SABRINA G. de M. ; MUCCILLO, ELIANA N. dos S. ; MUCCILLO, REGINALDO . Ionic conductivity of electric field-assisted sintered gadolinia-doped ceria/alkali salts membranes. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 299-299.

    Abstract: Ceramic-carbonate dual-phase membranes were prepared according to the usual procedure: by vacuum impregnation of molten sodium-lithium carbonates (NLC) into sintered porous ceria-20 mol% gadolinia (20GDC) solid electrolyte cylindrical pellets; and also by flash sintering samples with 75 wt.% (CeO2: 20 mol% Gd2O3) and 25 wt.% NLC. Sintering was accomplished by applying 200 V cm-1 to the membrane positioned in a sample holder of a dilatometer for monitoring thickness shrinkage, limiting the electrical current to 1 A. Electrochemical impedance spectroscopy measurements were performed in the 5 Hz-13 MHz frequency range from 300ºC to 600ºC in composite ceramic membranes, covering the solid-to-molten NLC temperature range. Analysis of the impedance diagrams allowed for the evaluation of the oxide ion and carbon dioxide ion conductivities. The Arrhenius plots showed the transition from oxide ion conduction (due to the solid electrolyte) to carbonate ion conduction (due to the molten NLC). The ionic conductivity values of membranes flash sintered at 420ºC in 2 min were higher than those of conventionally sintered membranes and similar to reported values of membranes sintered at 690ºC for 2 h.

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  • IPEN-DOC 28559

    DIAZ, JULIO C.C.A. ; MUCCILLO, REGINALDO . Impedance spectroscopy analysis of flash sintered zirconia: 8 mol% yttria solid electrolytes with alkali halide addition. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 298-298.

    Abstract: Electrical properties of porous ZrO2:8 mol% Y2O3 ceramics with LiF sintering aid were studied. The specimens were sintered by transient liquid phase formation under the application at 650ºC of 200 V cm-1 AC electric field for various current density, current elapsed time, and lithium fluoride content. Low electric current densities coupled with long application times produced homogeneous specimens. Variations in the electric current density and current elapsed time allowed to obtain sample densification in the 60%-75% range. Impedance spectroscopy measurements were carried out to estimate the relative pore content, evaluating the product of the blocking factor αR (=Rg/(Rg +Rgb), R, g and gb stand for resistance, grain and grain boundary, respectively) to the frequency factor αf (= fgb/fg, f is the characteristic frequency), which is proportional to the blocker volume, i.e., the porosity. A direct correspondence between αR•αf and the apparent porosity, obtained after determining the apparent density by the Archimedes method, was observed.

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  • IPEN-DOC 28558

    PELOSI, ANDRE G.; SANTOS, SABRINA N.C. dos; DIPOLD, JESSICA ; ANDRADE, MARCELO B. de; HERNANDES, ANTONIO C.; ALMEIDA, JULIANA M.P. de; MENDONCA, CLEBER R.. Investigation of the influence of transition metal ions in niobium-borotellurite glasses through vibrational and nonlinear optical spectroscopy. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 176-176.

    Abstract: Tellurite glasses are know as good candidates to photonic devices’ production because they exhibit third-order nonlinear optical susceptibilities larger than conventional silicate and borate glasses. In addition, for glass materials such nonlinearity can be increased by adding transition or heavy metal ions. In this direction, this work analyzed the influence of Ta5+ and Zr2+ on the physical, structures, and nonlinear optical properties of niobium-borotellurite (TBN) glasses. The samples were synthesized by the melt-quench technique using a melting temperature of around 1000 ºC. DSC measurements were performed to obtain the glass transition temperature. The densities were determined by the Archimedes method. To analyze the local structure of the samples FTIR and Raman spectroscopies were used . The spectrum of nonlinear refractive index (n2) for the TBN glass doped with Ta5+ and Zr2+ ions was measured using the tunable femtosecond Z-scan technique [1]. Such results were compared with the BGO model, which involves empirical relations between the linear and nonlinear refractive index. The addition of metal transition ions did not lead to meaningful changes in the glass transition temperatures (Tg). The formation of non-bridging oxygen and BO3 units was observed from the structural analysis. The n2 value determined indicates that the nonlinear optical responses are associated with the glass matrix. The structural changes caused by the addition of Ta5+ and Zr2+ demonstrated a decrease followed by an increase in the value of the molar electronic polarization of the samples, respectively.

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  • IPEN-DOC 28557

    DENALDI, RAFAEL L. ; MUCCILLO, REGINALDO . High temperature percolation of carbonate ions through porous alumina and zirconia-magnesia impregnated with alkali carbonates. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 305-305.

    Abstract: Na2CO3-K2CO3 (56-44 wt.%) eutectic composition was vacuum-impregnated into porous Al2O3 (alumina) and to ZrO2: 3 wt.% MgO (magnesium-partially stabilized zirconia, Mg-PSZ) at the molten eutectic temperature. Porosity was achieved in the two compounds by addition and thermal removal of the eutectic composition before impregnation. The parallel surfaces of disk-shaped impregnated compositions were observed in a scanning electron microscope. The CO3 2- carbonate ion conductivity of the two composite ceramics was measured by electrochemical impedance spectroscopy in the 5 Hz-13 MHz frequency range from 470ºC to 780ºC. The permeation of the carbonate ions via eutectic composition through the ceramic membranes was ascertained by the threshold temperatures of the onset of the carbonate ion percolation: 660ºC and 720ºC for alumina and Mg-PSZ, respectively.

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  • IPEN-DOC 28556

    SOUZA, JULIANA P. de; SERNA, JILDER D.P.; MORAES, LETICIA P.R. de ; SILVA, JULIO C.M.; ALVES, ODIVALDO C.. Structural and magnetic properties of CeO2 nanomaterials as a function of different morphologies: nanocube, nanowire and nanobelt. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 128-128.

    Abstract: The nanomaterials of cerium oxide can be applied in catalysts, fuel cells and spintronics [1]. Additionally, in its crystalline structure, small defects named oxygen gaps appear, caused by its high potential pattern of reduction from Ce IV to Ce III or that it becomes an oxidizing agent and the conferring agent. In this work we investigated the magnetic properties of three ceria morphologies on a nanometric scale: nanocubes, nanowires and nanobelt that were synthesized using the hydrothermal method. As samples prepared from studies by using X-ray diffraction (XRD), transmission electron microscopy (TEM), magnetometry (VSM) and paramagnetic resonance (EPR). XRD measurements show characteristic peaks of ceria fluorite face-centered cubic structure. Measurements of magnetization in function of the field applied at room temperature showing the ferromagnetic character with different values of the coercive field and saturation magnetization, we observe an increase in the coercive field and saturation magnetization in ceria nanocubes that can be explained by an increase in the density of vacancy [2]. The zero field cooled (ZFC) and field cooled (FC) magnetization curves measured on low magnetic fields show a soft maximum around 60 K attributed to oxygen at the sample surface. Applying to the Curie-Weiss equation indicates the presence of antiferromagnetic interactions mainly in nanobelt and nanocubes morphologies. The EPR spectra at room temperature show two paramagnetic symmetry, with axial symmetry with g1 = 1.97 and g2 = 1.94 associated with Ce 3+ and another isotropic around g = 2.03 due to vacancies of isolated oxygen for all samples. The ferromagnetic arrangement characterized by the presence of broad signals at about 3500 G is also observed in nanobelt morphologies.

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  • IPEN-DOC 28555

    ALVES, ANDRESSA A.; QUEIROZ, ÁLVARO A.A. de ; QUEIROZ, ALFREDO A.A.E. de. Fabrication of hyperbranched polyglycerols microcapsules from microfluidics guided by artificial neural networks. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 854-854.

    Abstract: In recent years, the microfluidic approach has received a lot of attention from the scientific community due to the simple and efficient synthesis of highly monodisperse microcapsules used in a variety of applications in biotechnology and medicine such as, for example, materials synthesis, drug encapsulation, among others [1,2]. Thus, in this work, hyperbranched polyglycerol microcapsules (HPGM) were developed using microfluidic technology. Artificial neural network (ANN) feed-forward using multilayer perceptron architecture was trained and applied to model and predict the microfluidic process. The HPGM produced were characterized by scanning electron microscope (SEM), attenuated total reflection-Fourier transform infrared (ATR-FTIR) and thermogravimetric analysis (TGA). The fabricated HPGM showed spherical size and monomodal distribution with an average diameter of 29 μm. The developed ANN proved to be efficient predictor, showing well agreement with the experimental data (R2=0.9983). Based on these results in this research, it was found that the microfluidic device for producing HPGM was successfully developed since it was possible to synthesize microcapsules with targeted properties, monodispersed with high stability and low porosity. In this way, microfluidic technology guided by ANN can be used to synthesize HPGM for biotechnology processes.

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  • IPEN-DOC 28554

    PORFÍRIO, TATIANE C. ; MUCCILLO, ELIANA N. dos S. ; MUCCILLO, REGINALDO . Electric field-assisted synthesis/sintering cerium oxide: 5 wt.% gadolinium oxide. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 321-321.

    Abstract: Gadolinium oxide ceramic powders were mixed to cerium oxide ceramic powders, pressed to pellets, and sintered either at 1450ºC for 4 h or applying 200 V cm-1 electric field at 800ºC, 900ºC and 1000ºC. The structural phases and the microstructure of the sintered pellets were analyzed by X-ray diffraction and scanning electron microscopy, respectively. The formation of substitutional solid solution was followed by monitoring the increase of the electrical conductivity by impedance spectroscopy measurements and the X-ray diffraction patterns. The main results show that Joule heating due to the flow through the pellets of the electric current, which was produced by the application of the electric field, allows for promoting partial solid solution as well as partial sintering the ceria-gadolinia pellets. Moreover, grain growth that occurred in the high temperature sintered pellets was inhibited in the electric field-assisted synthesized/sintered pellets, being an alternative technique for producing cerium oxide-gadolinium oxide solid solutions.

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  • IPEN-DOC 28553

    LANDGRAF, FERNANDO J.G.; MORAIS, WILLY A. de; GUZMAN, JHOAN; MARTORANO, MARCELO; NOBRE, RAFAEL de M.; NEVES, MAURICIO M. das . Effects of laser power and speed on keyhole formation during additive manufacturing by laser-powder bed fusion. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 656-656.

    Abstract: Unique microstructures are generated by the laser powder bed fusion (L-PBF) process of additive manufacturing. The moving molten metal pool created by the laser beam leaves a metallographic evidence, here called melt pool profile. The melt pool profile is easily identified in many alloys owing to the severe segregation at the beginning of the epitaxial cellular solidification, on the border of the remelted zone. The resulting microstructure is associated with the laser scanning strategy used in building the piece. Twenty-four different conditions of laser beam speed and power were adopted for a bed of plasma atomized powder of a Nb-48% Ti alloy. Width and depth of the melt pool profiles in the top layer of all samples were analyzed by optical microscopy. For lower energy densities and faster laser scanning speeds, the shape of the melt pool profile is nearly parabolic. When the speed decreases, within a certain limit dependent on the laser power, the shape changes to a characteristic keyhole-type profile, with a larger depth to width ratio. The keyhole profile is due to the presence of a wide, shallow parabolic pool and a narrow and deep pool formed by a transient evaporation cavity. The experimental results are compared to the available literature.

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  • IPEN-DOC 28552

    FRANCISCO, LEONARDO H.C. ; MOREIRA, RENAN P. ; SALVADOR, FRANCINE F. da S. ; MOTTA, MARCIO P.; FELINTO, MARIA C.F. da C. ; BRITO, HERMI F.. Near-infrared emitting Cr(3+)-doped mixed oxide luminescent materials for optical imaging. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 194-194.

    Abstract: The rapid growth of optical imaging in the latest years proposes novel alternatives to well-established imaging techniques, in a way that current research interest within this field is now focused on the design of efficient photonic materials and optical sensors[1-2]. In this scenario, this work presents the development of Cr3+-doped Zn/Mg/Sn mixed oxides prepared via solid-state and microwave synthesis, exhibiting interesting spectroscopic properties in the red to near-infrared (NIR) range. Prepared compounds were analyzed by PXRD, where the obtained diffraction profiles followed mainly the overlapping Mg2SnO4 and Zn2SnO4 patterns, and crystallite size was estimated to be about 70 nm. SEM/EDS analysis revealed micrometer-sized particles up to 20 μm, but much smaller particles and homogeneous Cr3+ distribution were also observed. Moreover, Synchrotron radiation measurements obtained at the Brazilian Synchrotron Light Laboratory, on the TGM beamline via Vacuum UV Spectroscopy within the 4.5–7.5 eV energy range revealed distinct emission profiles with increasing Zn concentration, affecting the contribution of deep-red and NIR vibronic sidebands at 700 and 720 nm, respectively. Still, maximum absorption energies (about 6.6 eV) remained constant for all the analyzed compounds, whereas the broad-band NIR emission of Cr3+ ion centered around 770 nm assigned to the [4T2(t2e)→4A2] transition is predominant. Persistent luminescence decay curves under near-band gap excitation were also probed. Thus, in this work, we demonstrated an effective way to assemble NIR emitting luminescent materials with potential applications in optical imaging and photonics, where similar and expensive Cr3+-doped gallates are already widely explored.

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  • IPEN-DOC 18922

    GOTTARDI, MARIELLA da S. ; KAWAMOTO, DIONE; ZAMATARO, CLAUDIA B. ; ANA, PATRICIA A. da ; MAYER, MARCIA P.A.; ZEZELL, DENISE M. . In vivo study of diode laser 940 nm operating in high intensity mode in the periimplantitis disease. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 62-62.

    Abstract: The evolution of periimplantitis has been associated with several risk factors. The standard treatment consists on subgingival scaling and blasting with sodium bicarbonate. This 6 months longitudinal clinical study evaluated and compared two treatment methods: conventional as described and complemented by irradiation with high intensity diode laser (940 nm, Biolase) aiming to establish a more efficient periimplantitis management. After approval by the Human Research Ethics Committee, 20 patients of both sexes, with implants in function for at least 12 months and with diagnosis of periimplantitis were selected and randomly distributed in two experimental groups. Ten of them were conventionally treated as control group, and the remaining ten were in the laser treated group (1W, 4.24kJ/ cm2 energy density, pulsed mode, 30s, twice). There were six sites for treatment standardization: vestibular region (mesial, central and distal thirds) and buccal region (mesial, central and distal thirds). Results has shown that overall clinical evaluation has no significant difference between groups control and treatment. less bleeding and suppuration, as shallower periodontal pocket indicated a decreasing tendency on laser treated group. Quantitation of total bacteria and Porphyromona gingivalis by real-time PCR shown that laser synergy is a complementary therapy that could act as an additional option to the conventional treatment in difficult response cases.

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  • IPEN-DOC 18813

    MORAES, MARCIA C.D. ; PEREIRA, DAISA L. ; ZAMATARO, CLAUDIA B. ; ZEZELL, DENISE M. ; FREITAS, ANDERSON Z. . Effect of Nd:YAG laser on caries prevention of dental enamel by optical attenuation coefficient with optical coherence tomography (OCT). In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 48-48.

    Abstract: Caries is a multifactorial disease, caused by the continuing loss of hydroxyapatite crystals. The association of topical acidulated phosphate fluoride application (APF) and high intensity lasers has the potencial to increase the resistance to demineralization of dental tissues. The Nd:YAG laser, specially associated to a photoabsorber over the dental surface, may induce thermal changes in order to increase the resistance to demineralization. Optical Coherence Tomography (OCT) is a non-ionizing radiation imaging technique that can be performed in real time in vivo and can detect early changes in the optical properties of t issues. This study aimed to characterize the effectiveness of the association of Nd:YAG la ser and APF gel in the prevention of caries lesions in human dental enamel in vitro, due to structural changes in function of the pH cycling, the treatments performed as well as to evaluate the potential of OCT to diagnose early demineralization. 160 human enamel samples were divided in four groups and submitted to pH cycling during 20 days, after the following treatments: G1- untreated; G2- treated with APF gel (1.23% F-, 4min); G3- irradiated with Nd:YAG (1064nm, 84.9J/ cm2, 10Hz) followed by APF application and G4- APF application before Nd:YAG laser irradiation (same conditions of G3). OCT (930 nm) analysis were performed before and after the treatments, 5th, 10th, 15th and 20th day of pH cycling. The optical attenuation coefficient decreased significantly (p<0.05) as demineralization increased over time and better results were achieved in group G4. OCT technique can diagnose early demineralization in enamel.

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  • IPEN-DOC 18688

    PEREIRA, DAISA L. ; MORAES, MARCIA C.D. ; ZAMATARO, CLAUDIA B. ; ZEZELL, DENISE M. . Longevity of diode laser irradiation in dentine: an in vitro study. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 47-47.

    Abstract: The efficacy of pulsed infrared lasers on clinical dentin wear sensitivity is well stablished in the Literature. This work aims to evaluate the effect of diode laser combined with fluoride products regarding the longevity of the sensibility treatment under the effect of the domestic use products. After Ethics Committee approval, 75 slabs of bovine root dentin measuring 8 mm2, were randomized into 5 groups (n=1 5): G1- untreated; G2- treated with acidulated phosphate fluoride (APF-gel, [F-J=1.23 %, pH=3.3 to 3.9); G3- irradiated with diode laser (980 nm, 2.5W, 5ms, 25Hz) using a cool paste as photoabsorber; G4- irradiated with diode laser (same conditions of G3) using a coal paste as photoabsorber + application of APF-gel and G5- application of APF-gel+ diode laser irradiation (same conditions of G3). All samples were submitted to an erosive and abrasive demineralization (Sprite Zero, pH=2.8, 90s, 4x/day), and remineralization (artificial saliva, pH=7.4) cycling for 10 days. Twice a day, slabs were brushed for 15s using a whitening dentifrice (Sensodyne True White, GSK, EUA). Slabs were evaluated by Optical Coherence Tomography (OCT) at the initial and 7th day of cycling. OCT measurements found a significant increase on dentin wear depth and area of lesions with the increase of cycling days. G1 and G2 hod significant higher mineral loss compared to the other groups. G3, G4 and GS showed no significant differences between them. Results suggested that the sensibility of the treatment with the diode laser has longevity despite the high abrasivity of dentifrice used in maintenance.

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  • IPEN-DOC 18613

    ZAMATARO, CLAUDIA B. ; PEREIRA, DAISA de L. ; LIMA, CASSIO A. ; SCAPIN, MARCOS A. ; ZEZELL, DENISE M. . Gamma sterilized human dental enamel submitted to Er,Cr: YSGG laser irradiation associated to fluoride for in situ model. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 89-89.

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  • IPEN-DOC 18533

    BEZERRA, SAVIO J.C.; TREVISAN, LETICIA R.; VIANA, ITALLO E.L.; LOPES, RAQUEL M.; PEREIRA, DAISA de L. ; SAKAE, LETICIA O.; ARANHA, ANA C.C.; SCARAMUCCI, TAIS. Er,Cr:YSGG laser associated to fluoride on the control of dentin erosion progression. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 88-88.

    Abstract: 1) Introduction: The combination between high power lasers and fluoride may potentially control the progression of dentin erosion. Therefore, the aim of this study was to evaluate the effect of Er,CrYSGG laser, associated to fluoride application, in the control of dentin erosion. 2) Materials and Methods: Dentin slabs were embedded into acrylic resin, flattened and polished. The specimens (n=10) were previously eroded (10min immersion in 1% citric acid solution) and randomly allocated into the experimental groups, according to the following treatments: control (no treatment); acidulated phosphate fluoride (APF) gel (1.23% F, 1min); Er,Cr:YSGG laser irradiation (parameter 1: 0.25W, 20Hz, 2.8J/cm2); Er,Cr:YSGG loser irradiation (parameter 2: 0.50W, 20Hz, 5.7J/cm2); APF gel+Er,Cr:YSGG laser parameter 1 and; APF gel+Er,Cr:YSGG laser parameter 2. After, they underwent on erosion-remineralization cycling, consisting of a 5min immersion into 0.3% citric acid, followed by 60min exposure to artificial saliva. This procedure was repeated 4x/day, for 5 days. Surface loss (SL, in μm) was determined with optical profilometry. The specimens were analyzed by environmental scanning electron microscopy (n=3). Data were statistically analyzed (α=0.05). 3) Results: None of the groups significantly differed from the control group, except for the APF group. APF gel presented the lowest SL, not differing from Er,Cr.YSGG laser (parameter 1) and APF gel+Er,Cr:YSGG laser (parameter 1). Selective structure removal was observed for the laser-treated groups. 4) Conclusions: None of the Er,Cr:YSGG laser parameters were effective in the control of dentin erosion. The laser was also not able to enhance the protection of fluoride against dental erosion.

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  • IPEN-DOC 18453

    YOSHIKAWA, HELENICE Y.; DAGUANO, JULIANA K.M.B.; PEREIRA, DAISA L. ; ZEZELL, DENISE M. ; ANA, PATRICIA A. . Effects of Er,Cr:YSGG laser and a bioactive glass on root caries remineralization. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 87-88.

    Abstract: Considering the aging of the population, the greater exposure of the root surfaces and the higher caries risk in these surfaces, the development of strategies that efficiently remineralize root caries lesions in a long-lasting way is strictly necessary. This in vitro blind randomized study evaluated the potential of remineralization of root caries lesions promoted by Er,Cr:YSGG laser irradiation (2.78 μm) associated with a bioactive glass (Biosilicate ®). 60 bovine root dentin slabs with incipient caries lesions were distributed in 6 experimental groups {n:::15l, in order to be treated with laser irradiation (0.25W, 12.5 mJ/pulse, 2.8 J/cm2, 20 Hz, without refrigeration), application of Biosilicate® or association of both. After the treatments, the samples were subjected to an 8-day pH-cycling regimen, and further evaluated by Fourier transformed infrared spectroscopy {FTIR), optical coherence tomography (OCT) and scanning electron microscopy. The data were statistically analyzed at a 5% significance level. The Biosiljcate ® promoted the formation of carbonated hydroxyapatite even before loser irradiation, which was better retained after demineralization in loser irradiated group. The Biosilicote® and the la ser irradiation alone provided the remineralization of the root dentin in a similar way to that promoted by the topical application of acidulated phosphate fluoride, since all groups had comparable optical attenuation coefficients. The association of the Biosilicate® with the loser irradiation showed higher optical attenuation coefficient than the other experimental groups. It was concluded that the association of Biosilicote® with laser irradiation promoted a synergistic effect, augmenting the remineralization of root dentin and preventing the progression of caries.

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  • IPEN-DOC 18341

    PEREIRA, DAISA L. ; GOMES, GABRIELA V. ; SUGAHARA, VANESSA M.L.; SCAPIN, MARCOS A. ; ANA, PATRICIA A. ; ARANHA, ANA C.C.; ZAMATARO, CLAUDIA B. ; ZEZELL, DENISE M. . Nd:YAG laser irradiation of darkened dental enamel by means of dentrifice use. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser in Dentistry, 2018. p. 87-87.

    Abstract: As the world population is growing older, dental erosion became a real concern on dentistry. Optical Coherence Tomography and X-Ray fluorescence were used to analyze enamel samples covered by black dentifrice as photoabsorber irradiated with NdYAG laser, then submitted to an erosive cycling. Heat injury risk in deeper tissue decreases because of the dentifrice dark pigment, when the most of photons are absorbed in the surface. Sixty Bmm2 blocks of bovine enamel, were randomized into 4 groups: G1- untreated; G2- treated with acidulated phosphate fluoride (APF, [FJ::1.23%, pH::3.3 to 3.9); G3- irradiated with Nd:YAG laser (1064nm, 0.6W, 10Hz- Lares Research®) using a coal paste as photoabsorber; G4- irradiated with Nd:YAG laser (1064nm, 0.6W, 10Hz), using a black dentifrice (Black is White, Curaprox®). All samples were submitted to a 3-day erosive demineralization (Citric acid 1%, pH::3.6, 5min, 2x/day) under agitation, and remineralization cycling (artificial saliva, pH::7, 120minJ. After treatments and pH cycling, the [Ca]/[P] ratio decreased in the laser irradiated groups. The samples were evaluated by OCT before and after treatment and after erosive cycling. OCT measurements found smaller lesion depths in laser irradiated groups than in the other groups and there were statistically significant differences between G3 and G4 groups (p<0.05). Heating promoted by Nd:YAG laser irradiation changed the morphological and crystallographic enamel surface properties and has shown to be a promissory alternative to prevent erosion.

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  • IPEN-DOC 17850

    LOPES, MONICA S.; PEREIRA, DAISA L. ; MOTA, CLAUDIA C.B.O.; ANA, PATRICIA A. ; ZEZELL, DENISE M. ; GOMES, ANDERSON S.L.. Shear bond strength of lingual brackets on enamel surface submitted to acid-etching or Nd:YAG laser irradiation. In: LASER DENTISTRY WORLD CONGRESS, 16th; DGL ANNUAL MEETING, 27th; INTERNATIONAL WALED CONGRESS, 6th, October 1-3, 2018, Aachen, Germany. Abstract... Aachen, Germany: International Society for Laser Dentistry, 2018. p. 82-82.

    Abstract: The patient demand for aesthetic orthodontic solutions is driving for use of lingual brackets and laser irradiation can prevent dental caries in this region. This in vitro study is the first one in literature that aimed to quantify the shear bond strength (SBS) on direct lingual b rackets bonding after different enamel surface pre-treatments. 75 bovine incisor teeth were randomized in 5 groups (n=15): G1- untreated; G2- treated with acidulated phosphate fluoride gel (APF-gel, [F-] =1.23%, pH=3.3 to 3.9); G3- conditioned with 37% phosphoric acid (Condoc 37%, FGM, Brazil) and treated with APF-gel; G4- irradiated with Nd:YAG loser (1064nm, 0.6W, 10Hz- Laser Research) and treated APF-gel; GS- irradiated with Nd:YAG laser + conditioned with 37% phosphoric acid + treated with APF-gel. The positioning of the brackets was standardized during the bonding procedure using a positioner and Transbond XT adhesive (3M Unitek, USA) was used. After bonding, all samples were thermocycled (500 cycles between SoC and 55°C) and submitted to a 48h cariogenic challenge. After cycling, the samples were tested for shear bond strength (SBS) in a universal testing machine (0.5mm/min). SBS test values were statistically higher (p<0.05) in the G3 and G5 groups when compared to the other groups. This study showed that the Nd:YAG loser irradiation improved dental adhesion and increased the mechanical resistance of the enamel because the heating promoted by Nd:YAG laser irradiation changed the morphological and crystallographic properties of enamel; in this way, this treatment also offers the advantage to prevent caries around brackets.

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  • IPEN-DOC 14839

    HARAGUCHI, MARCIO I.; KIM, HAE Y.; SPRENGER, FRANCISCO E. ; CALVO, WILSON A. P. . Imaging technique for troubleshooting of industrial equipment by gamma-ray absorption scans. In: DUDALA, JOANNA (Ed.); STEGOWSKI, ZDZISLAW (Ed.) INTERNATIONACONFERENCE ON DEVELOPMENT AND APPLICATIONS OF NUCLEAR TECHNOLOGIES, September 11-14, 2011, Krakow, Poland. 2011. p. 135.

    Abstract: Gamma scanning is one of the most common nuclear techniques on troubleshooting industrial equipments like distillation columns and reactors. With a very simple concept, the technique is easy to implement. Searching for a competitive edge the industry has been long developing solutions to achieve better results. On the last decades, significant development has been done with the advent of new equipments, electronics, portable computers and software, to the point that nowadays the field work and reporting can be done in a question of hours. Continuous scanning and wireless detection systems are examples of successful field solutions, while new software aid on reporting and data presentation. However the type and quality of the results itself has not dramatically changed since its beginning. A scan profile is simple to understand, although the process to build it can be very complex as it requires a specific blend of knowledge and abilities. Process Engineering, Chemical Engineering, Internal Hydraulic Project, Nuclear Engineering and field abilities are pre requisites for of any scan specialist rookie. Correct data gathering, interpretation and reporting are abilities often difficult to match or requires a long time of training. Probably there are no more than a handful of scan specialists on the world. The industry faces a similar difficult on the customer side, as it is always necessary to train end users to understand a report and how to use its best. This paper describes our effort on developing a new approach on the gamma scan test using image reconstruction techniques that would result on a graphic image rather than a XY plot. Direct and easier to understand, a report with graphic images would be also accessible to a wider audience, not limited to the customers experienced with gamma scan interpretation.

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  • IPEN-DOC 17421

    FEIST, I.; ANDRADE, A.K.P.; DE MICHELI, G.; CAI, S.; PANUTTI, C.; ZEZELL, D. ; EDUARDO, C.P.. Bacterial reduction in class II furcation after root debridment with or without Nd:YAG laser irradiation. In: LASER CONGRESS; CONGRESS OF THE EUROPEAN SOCIETY FOR ORAL LASER APPLICATIONS, 3rd; CONGRESO DE LA SOCIEDAD ESPANOLA DE LASER ODONTOESTOMATOLOGICO, 6th; CONGRESSO DELLA SOCIETA ITALIANA DI LASER IN ODONTOIATRIA, 4th, May 19-21, 2005, Barcelona, Spain. Abstract... Vienna, Austria / Barcelona, Spain: European Society for Oral Laser Applications - ESOLA / Sociedad Española de Láser Odontoestomatológico - SELO, 2005. p. 14-15.

    Abstract: The use of Nd:YAG laser for bacterial reduction as an adjuvant to non-surgical periodontal treatment has been approached in several studies. Furcation complex anatomy is responsible for comprised treatment results in this areas due to the lack of proper access for instrumentation showing the persistence of a pathogenic microbial flora. The purpose of this clinical trial, randomized, double-blinded was to evaluated the bacterial reduction achieved with the Nd:YAG laser associated to conventional treatment on furcation sites of 17 patients with chronic periodontitis. They received previous full mouth periodontal treatment except for the experimental sites. In a split mouth design study, 34 class 11 furcations were selected and divided in two groups. The 17 furcations of the control group underwent twice manual and ultrasonic root debridment in weekly intervals. The test group received the same treatment as the control group followed by the Nd:YAG laser application (100 mJ/pulse, 1.5 W, 15 Hz, 60 see.). The microbiological parameters - total number of anaerobic Colony Forming Units (CFU), Black pigmented CFU and the level of A. actinomycetemcomitans, P. gingivalis and P. intermedia - were determined at baseline. immediately and one month after the treatment. The results showed a significant reduction of total CFU for both groups immediately after treatment, but it was better for the test group. After one month the total CFU average increased but was still below pretreatment levels for both groups. The Black pigmented CFU and the level of A. actinomycetemcomitans. P. gingivalis and P. intermedia decreased significantly after the treatment but 30 days after. there was an increase almost equal to baseline levels for both groups. The Nd:YAG laser associated with conventional treatment promoted bacterial reduction on class II furcation immediately after its application.

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  • IPEN-DOC 14692

    MARQUES, M.M.; HAYPEK, P.; EDUARDO, F.P.; MIGLIORATI, C.A.; ZEZELL, D.M. ; EDUARDO, C.P.. Effect of high intensity diode laser irradiation on growth of human gingival fibroblasts. In: LASER CONGRESS; CONGRESS OF THE EUROPEAN SOCIETY FOR ORAL LASER APPLICATIONS, 2nd; CONGRESSO DELLA SOCIETA ITALIANA DI LASER IN ODONTOIATRIA, 2nd, May 15-18, 2003, Florence, Italy. Abstract... Vienna, Austria / Roma, Italy: European Society for Oral Laser Applications - ESOLA / Società Italiana di Laser in Odontoiatria - SILO, 2003. p. 38-38.

    Abstract: Purpose: Diode lasers present some advantages over the other surgical lasers. The equipments are more compact and can also be used in low intensity laser therapy. The aim of this study is to analyze a possible biostimulatory effect of the diode laser on human cultured gingival fibroblasts. Material and Methods: The celll ine FMM1 was grown in Dulbecco' modified Eagle medium. Laser irradiation was carried out with a GaAIAs diode laser (wavelength: 808 nm, power output: 3.5 W, Zap Lasers, CA, USA). The irradiation was done in a defocused and continuous wave mode using a fiber of 400 micrometers. The experiments were done in triplicate (Group 1: non-irradiated cells; Group 2: cells irradiated with 3 J/cm2; and Group 3: cells irradiated with 4 J/cm2). The data of the growth curves were analyzed by statistical means. Results and Conclusion: The defocused diode laser irradiation used as low intensity laser therapy presents biostimulatory effect on growth of human gingival fibroblasts.

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  • IPEN-DOC 28460

    BACHMANN, LUCIANO; PEREIRA, THIAGO M.; ZEZELL, DENISE M. ; FELIPE, JOAQUIM C.. Vibrational spectroscopy of biological tissues. In: ENCONTRO DE OUTONO DA SOCIEDADE BRASILEIRA DE FÍSICA, 44., 21-25 de junho, 2021, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2021.

    Abstract: The vibrational modes of molecules in biological tissues can be assessed by either Raman spectroscopy, through inelastic scattering, or infrared spectroscopy, through direct measurement of transmittance or reflectance. When combined with mathematical methods, vibrational spectroscopic techniques have shown promising results for evaluation of biochemical changes in biological samples, and such combination can be used to develop new tools for medical diagnosis. Here, we provide an overview of the infrared spectral imaging techniques we use to characterize biological tissues and describe how we employ these techniques to diagnose cancer and to evaluate inflammatory processes. In the last decade, we have studied thyroid and colon cancer tissues as well as inflammatory processes attributed to an early stage of cancer. All the samples were obtained from human biopsy embedded in paraffin and cut according to the usual procedures in pathology. The sample slides were deposited over a Calcium Fluoride window that is transparent in the infrared spectral region. An FTIR spectrometer with 4-cm-1 resolution coupled to a microscope with 6x6 microns of effective pixel size was employed. Pre-processing algorithms were necessary to remove unwanted absorption bands such as water vapor, carbon dioxide, and paraffin absorption bands. After that, the data of hyperspectral images were processed to classify and to predict tissue regions by using machine learning techniques. More recently deep learning algorithms have been employed to pre-diagnose colon and thyroid cancer. Aiming to identify tissue changes, deep neural networks can be trained under a supervised process by using the spectral values in different frequencies. The proposed study can be extended to other tissues and applied to a wide range of samples. A good dataset of samples to train the algorithms is key to achieving higher accuracy.

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  • IPEN-DOC 28459

    CASTRO, PEDRO A.A. ; PEREIRA, DAISA L. ; ZEZELL, DENISE M. ; RIBEIRO, HENRIQUE B.; MATOS, CHRISTIANO J.S.; ANA, PATRICIA A.. Confocal Raman spectroscopy characterization of Nd:YAG laser irradiation on dental enamel for erosion prevention. In: ENCONTRO DE OUTONO DA SOCIEDADE BRASILEIRA DE FÍSICA, 44., 21-25 de junho, 2021, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2021.

    Abstract: Confocal Raman spectroscopy is a non-destructive and non-invasive method used to obtain spectral features of biological structure and depth images without coming into contact with the sample. Biochemical content obtained by Raman microscopy is related to the characteristics of the tissues, allowing experimental use without any side effects to the sample. Complex biomolecular features can be resolved through confocal Raman imaging analysis with subcellular spatial resolution by using a single excitation wavelength laser to identify a large range of biomolecules. This work aims to characterize dental enamel irradiated by Nd:YAG laser and correlate the modified tissue in depth due to the heat propagation caused by laser absorption. For this, 30 blocks of bovine enamel were randomized into 3 groups: G1- enamel untreated; G2- enamel irradiated with Nd:YAG laser (1064 nm; 120s pulsewidth, 10Hz; 84,9 mJ/cm2; Lares Research) using a squid Ink as photoabsorber; G3- enamel irradiated with Nd:YAG laser (1064 nm; 5 ns; 20 Hz; 1,05 J/cm2 Brilliant, Quantel Laser) using a coal paste as photoabsorber. The phosphate intensity band was used as a spectral indicator of the groups characteristics. The Raman spectra of the Nd:YAG irradiated samples detected a phosphate intensity reduction in the G3 group after laser irradiation. There were distinct differences in the chemical activity after the laser irradiation and these findings, associated with the previous studies of our group, were related to the stability of the apatite, accompanied with the increased susceptibility to demineralization. The carbonate free apatite has been characterized as less likely to be affected by acid challenge. Based on our initial results, the thickness of the treated area is a critical variable in determining the resistance of erosion, especially for the type of photoabsorber associated with Nd:YAG. Our findings demonstrate the coal paste as a more resistant material to enamel erosion prevention. Therefore, fiber-optic confocal Raman imaging have shown potential to be an established spectroscopic choice for carie real-time monitoring.

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  • IPEN-DOC 28458

    DEL-VALLE, MATHEUS ; SANTOS, MOISES O. dos ; SANTOS, SOFIA N. dos ; BERNARDES, EMERSON S. ; ZEZELL, DENISE M. . A deep learning approach for breast tissue malignancy diagnosis using micro-FTIR hyperspectral imaging. In: ENCONTRO DE OUTONO DA SOCIEDADE BRASILEIRA DE FÍSICA, 44., 21-25 de junho, 2021, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2021.

    Abstract: The breast cancer is the most incident cancer in women with an estimative of 2.1 million new cases in 2018. With the grown of deep learning techniques, several approaches in vibrational spectroscopy have been studied. In this way, this work aimed to classify breast samples as breast cancer or adenosis using a deep learning model. It was used the human breast cancer microarray BR804b (Biomax, Inc., USA), where one core of each group, cancer and adenosis, was imaged by a Cary Series 600 micro-FTIR imaging system (Agilent Technologies, USA). The system has a spatial resolution of 5.5 μm and about 100 thousand spectra were acquired for each group. The regions of interest were selected by two k-means clustering using amide I/II (1700 to 1500 cm-1) and highest paraffin intensity (1480 to 1450 cm-1) bands. Spectra were preprocessed by five steps: outlier removal using Hotelling’s T2 versus Q residuals; biofingerprint truncation; Savitzky–Golay filtering for smoothing and second derivative; Extended multiplicative signal correction (EMSC) with digital de-waxing; another outlier removal. The deep learning model was a convolutional neural network (CNN) fused with a fully connected neural network (FCNN). The CNN was built with 2 Conv1D-ReLU-MaxPooling1D-Dropout layers. The kernel size was set to 5 and dropout of 0.5. Dense layers were built by two layers of neurons-BatchNorm-ReLU-Dropout, with 100 and 50 neurons, dropout of 0.2. The output was a single neuron with sigmoid activation. Binary cross-entropy loss function was adopted with Adam optimizer. Accuracy metric was calculated during the training, where a threshold of 0.5 was applied on the output predictions. Model was trained by a 4-fold cross-validation by 20 epochs and using a batch size of 250. The train accuracy was 0.978/0.004 (mean/std), while the testing accuracy was 0.969/0.008, demonstrating a generalized model without overfitting. Accuracies near one indicate the proposed model as a potential technique for the breast cancer vs adenosis classification, where hyperparameters and the architecture should be optimized along higher sample number acquisition.

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  • IPEN-DOC 28457

    BRANCO, ISABELA S.L. ; BURIN, ANA L. ; YORIYAZ, HELIO . Métodos para criação de Spread-Out Bragg Peaks em protonterapia. In: CONGRESSO BRASILEIRO DE FÍSICA MÉDICA, 25., 19-23 de abril, 2021, Online. Resumo... 2021.

    Observação: Vídeo de apresentação: https://youtu.be/Gx8gj17Ayh4

    Abstract: Em tratamentos com feixes de prótons, as distribuições de dose longitudinais caracterizam-se pela presença do pico de Bragg (Bragg Peak - BP). A sobreposição de vários picos com diferentes energias e a ponderação de cada um fazem-se necessárias para irradiar homogeneamente um grande volume tumoral, criando um Spread-Out Bragg Peak (SOBP). O objetivo deste trabalho consiste em analisar três diferentes métodos para criação dos SOBPs – método de Bortfeld, método da função inversa e método das matrizes. Simulações de Monte Carlo foram realizadas com o software TOPAS, nelas, feixes monoenergéticos de prótons incidiram em um objeto simulador retangular de água para que distribuições de dose fossem contabilizadas em profundidade. O método das matrizes conseguiu ajustar o peso de cada curva de forma a produzir SOBPs com melhor homogeneidade, ao mesmo tempo que, os dois outros métodos foram mais custosos computacionalmente.

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  • IPEN-DOC 28456

    BURIN, ANA L. ; BRANCO, ISABELA S.L. ; YORIYAZ, HELIO . Estudo dos parâmetros WER e WET em protonterapia com simulações de Monte Carlo. In: CONGRESSO BRASILEIRO DE FÍSICA MÉDICA, 25., 19-23 de abril, 2021, Online. Resumo... 2021.

    Observação: Vídeo de apresentação: https://youtu.be/3cvapMx0WJ0

    Abstract: O presente trabalho apresenta um estudo comparativo dos valores da razão equivalente de água (WER – Water Equivalent Ratio), e da espessura equivalente de água (WET – Water Equivalent Thickness) para várias energias obtidos com os códigos de Monte Carlo (MCNP6 e TOPAS) em protonterapia. Para utilizar plenamente as vantagens dosimétricas que a terapia de prótons proporciona, o conhecimento exato do alcance do feixe (range) é essencial. Os parâmetros WER e WET são utilizados para relacionar o range em água com outros materiais e tecidos do corpo humano. Nesse contexto, o principal objetivo deste trabalho é contribuir com o aprimoramento do cálculo de dose em protonterapia, mais especificamente no cálculo de WER e WET em meios tecidos equivalentes. O estudo demonstrou que os valores de WER e WET são constantes com a energia, sendo que, as diferenças relativas encontradas foram inferiores a 1% para ambos os parâmetros, o que simplificará os cálculos de dose futuros.

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  • IPEN-DOC 28455

    ROMBALDI, PAULO V.L. ; MAZER, AMANDA C. ; SHORTO, JULIAN M.B. ; RIBEIRO, VICTOR A.B. ; YORIYAZ, HELIO . Comparação da distribuição de dose experimental e calculada por Monte Carlo de uma unidade de raios-X XVI da Elekta ®. In: CONGRESSO BRASILEIRO DE FÍSICA MÉDICA, 25., 19-23 de abril, 2021, Online. Resumo... 2021.

    Observação: Vídeo de apresentação: https://www.youtube.com/watch?v=MrvAydGtQjA

    Abstract: Com o aumento do uso das tecnologias de IGRT na prática clínica, há uma preocupação com uma possível adição significativa de dose de radiação aos tecidos sadios do paciente, aumentando o risco de induzir cânceres secundários por exposições concomitantes. O propósito deste estudo consiste em quantificar a dose concomitante recebida por pacientes em tratamento com Radioterapia Guiada por Imagem (IGRT) exclusivamente devido aos raios-X produzidos pela unidade XVI, unidade de tomografia computadorizada de feixe cônico (CBCT) acoplado ao acelerador linear da Elekta, localizado no ICESP (Instituto do Câncer do Estado de São Paulo). Também foram realizadas comparações de dados obtidos a partir de medidas experimentais e simulações com o código de Monte Carlo MCNP6.

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  • IPEN-DOC 28454

    HERBST, LUCAS S.; RODRIGUES, LETICIA L.C. . Análise Qualitativa de medida de distribuição de dose em Braquiterapia com Dosímetro Fricke Gel utilizando imagem em Ressonância Magnética. In: CONGRESSO BRASILEIRO DE FÍSICA MÉDICA, 25., 19-23 de abril, 2021, Online. Resumo... 2021.

    Observação: Vídeo de apresentação: https://youtu.be/S3pY74iRk6Y

    Abstract: Com a popularização de imagens tridimensionais, técnicas como IMRT e VMAT são constantemente estudadas e estão sob forte escrutínio científico. Geralmente a braquiterapia fica sob um holofote menos intenso, e acaba ficando em segundo plano nos serviços. O Brasil utiliza a técnica principalmente em tratamentos ginecológicos, embora tratamentos pélvicos masculinos estejam cada vez mais comuns. Com a migração dos serviços de uma técnica baseada em prescrições de dose em pontos, para um cálculo tridimensional cada vez mais o interesse por uma avaliação da distribuição de dose aumenta. Esse trabalho busca avaliar o uso de um dosímetro verdadeiramente tridimensional para medir essas distribuições de dose. Primeiramente foi realizada a calibração do dosímetro com imagens de ressonância magnética. Posteriormente uma irradiação utilizando uma sonda de titânio com uma única parada foi avaliada qualitativamente. O planejamento foi feito utilizando o algoritmo Acuros BV, um dos mais novos disponíveis no mercado, e em boa correlação com cálculos com Monte Carlo. Cada ponto foi calculado como a média com os pontos vizinhos, para diminuir ruídos da imagem, tornando-a mais suave. Visualmente existe uma boa correlação entre as medições e o planejamento, em uma continuação do trabalho, uma análise quantitativa utilizando avaliação gama será realizada.

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  • IPEN-DOC 28453

    MAZER, AMANDA C. ; YORIYAZ, HELIO . Algoritmo para avaliação de registro de imagem baseado na técnica SIFT (Scale Invariant Feature Transform). In: CONGRESSO BRASILEIRO DE FÍSICA MÉDICA, 25., 19-23 de abril, 2021, Online. Resumo... 2021.

    Observação: Vídeo de apresentação: https://youtu.be/k1405XduFEo

    Abstract: A avaliação de um registro de imagem deve ser feita a partir de um grande número de pontos distribuídos pelas imagens utilizadas no processo. Neste trabalho, a técnica SIFT, que permite extrair automaticamente pontos estáveis de uma imagem, foi utilizada para desenvolver um algoritmo na linguagem Python para ser aplicado para avaliação de registro de imagens médicas 3D. Imagem de TC (tomografia computadorizada) foi usada para realizar testes de redundância envolvendo diferentes transformações, a fim de obter pontos correspondentes entre a imagem original e a imagem sintética transformada. Para todos os testes, o algoritmo foi capaz de identificar pontos estáveis, em que a maioria era verdadeiramente correspondente, de acordo com diferentes margens de erro. Entretanto, o algoritmo ainda se encontra em fase de validação.

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  • IPEN-DOC 28452

    FERREIRA, MARIA C. de M.S.C.; CASTRO, PEDRO A.A. de ; PERALTA, FELIPE da S.; KITAKAWA, DARCIO; ZEZELL, DENISE M. ; CARVALHO, LUIS F. das C. e S. de. Optical biopsy and artificial intelligence as a diagnostic tool of smokers: a pilot study. In: FÓRUM ON-LINE DE TECNOLOGIAS DA LUZ NA SAÚDE, 2nd, May 20-22, 2021, Online. Abstract... Campinas, SP: Faculdade São Leopoldo Mandic, 2021.

    Abstract: Background: FT-IR spectroscopy can investigate and detect tissue changes at biochemical levels, the result is obtained quickly, it needs a small sample amount, which can be biofluids. Objective: Compare saliva between smoking and non-smoking patients by FT-IR spectroscopy, as an optical biopsy technique and associate with data processing methods based on artificial intelligence. It will be possible to investigate biochemical changes at the molecular level, and in the future use it as an early diagnosis of oral cancer. Methodology: This study was approved by the Research Ethics Committee, and was conducted using a FT-IR spectroscopy coupled with and attenuated total reflection accessory. Volunteers were divided into three groups, however just 10 patients were analyzed as pilot study. In control group were collected saliva of volunteers who had never tried tobacco (15 spectra from 5 samples). In smoking group patients over 40 years old who smoke more than one pack of cigarettes a day (3 spectra from 1 sample); In sporadic smoking group, patients who smoke sporadically and/or socially (12 spectra from 4 samples). Results: In all groups, the structural components were DNA, RNA, lipids, proteins and Amide. The spectra showed different intensities in the respective structural components mentioned above, so that subtle differences could prove that the saliva of smoking patients has differences with normal patients. Conclusion: Optical biopsy and artificial intelligence could be used in the medical field, it is a safe and label technique, more patients should be analyzed for solid results.

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  • IPEN-DOC 28451

    OLIVEIRA, ANDRESSA B.; FAGUNDES, JESSYCA L.A.; VEADO, HENRIQUE C.; FORTES, BEATRIZ N.A.; BITTENCOURT, ALEXANDRA A.; ADORNO, JOSE; CASTRO, MARCIO B.; VASQUEZ, PABLO A.S. ; SANTOS, PAULO S. ; DALLAGO, BRUNO S.L.; CAMPEBELL, RITA C.. Uso de pele de rã na cicatrização de feridas em equinos / Use of frog skin in wound healing in horses. In: SIMPOSIO INTERNACIONAL DO CAVALO ATLETA, 5., April 26-30, 2021, Online. Abstract... Belo Horizonte, MG: EV-UFMG, 2021.

    Abstract: A pele de rã (Rana catesbeiana) possui peptídeos com ação antimicrobiana, resistência mínima a perda de água e otimiza o processo cicatricial de feridas. Objetivou-se avaliar a cicatrização de feridas experimentais tratadas com pele de rã (GPR), desidratada e esterilizada com raios gama, comparando os achados clínicos e histopatológicos com feridas tratadas com ringer com lactato (GC). Utilizando-se cinco equinos saudáveis, foram realizadas feridas (3 x 3 cm), duas de cada lado da região lombar, distantes 7 cm, incluindo pele e subcutâneo, sendo que um lado foi realizado avaliação clínica e outro histopatológica, aleatoriamente. Durante o período experimental, realizaram-se avaliações e coletas para exame histopatológico nos dias 0, 3, 7, 14 e 21, e curativos diários no GC e troca de pele, a cada 3 dias no GPR. Observou-se o preenchimento total do leito da ferida por tecido de granulação no 14º dia, nos dois grupos e epitelização evidente em ambos grupos no 21º dia. As menores médias das áreas das feridas e as maiores taxas de contração foram observadas no GPR até o 7º dia. No entanto, nas aferições seguintes, o GC apresentou menores médias de área e maiores taxas de contração. Na avaliação histopatológica o GPR apresentou maior fibroplasia e neovascularização precoce até o 7º dia, mas posteriormente, notou-se essas características mais acentuadas no GC. Não foram observadas diferenças estatísticas entre os grupos estudados. De acordo com os resultados obtidos, a pele de rã possui precoce neovascularização e fibroplasia, podendo ser um potencial curativo biológico temporário em equinos.

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  • IPEN-DOC 28450

    GOMES, ALISSANDRA de M. ; JESUS, GUSTAVO P.P. de ; ZACARIAS, ENIO A. ; YOSIDAKI, VANESSA L. ; LIMA, DARLE B. de ; COSTA, RAFAEL S. ; RANGEL, ERIKA B.; SOUSA, POLIANA E.S.; SILVA, CHRISTIAN S.; BARTOLINI, PAOLO ; PERONI, CIBELE N. . A comparison between two populations of mesenchymal stem cells that can improve the osteogenesis imperfecta mouse phenotype. In: CONGRESS OF THE BRAZILIAN SOCIETY FOR CELL BIOLOGY, 20th, January 27-29, 2021, Online. Abstract... São Paulo, SP: Sociedade Brasileira de Biologia Celular, 2021. p. 249-250.

    Abstract: Osteogenesis imperfecta (OI) is an inherited disease characterized by fragility, deformity and low bone density, besides other clinical manifestations. Type-I OI is the mildest and most common form of the disease, caused by a mutation in the COL1A1 gene and resulting in half normal-collagen production. Our purpose was to compare mesenchymal stem cells from bone marrow (BM-MSCs) with those from adipose tissue (AD-MSCs), both used for improving heterozygous oim mice phenotype, similar to human type-I OI. Mice were irradiated and cells injected into femoral condyles, bone mineral density (BMD) and femoral length were measured by X-ray, at the beginning and end of the assay. Femurs and quadriceps allowed bone fragility evaluation by biomechanical test and collagen Col1a1 and Col1a2 quantification via ELISA. BMD showed no significant difference between the groups, while femur length variation was higher in the BM-MSCs group, compared with the control (P=0.0301). Fragility was improved with AD-MSCs when flexion extension to fracture (P=0.0028) and time to fracture (P=0.0032) were evaluated. There was no significant difference in the maximum load supported by femurs until fracture. An increase in Col1a1 concentration with BM-MSCs in comparison with AD-MSCs (P=0.0281) was obtained. Although no significant difference in Col1a2 concentration was observed between the groups, a higher expression level was obtained with AD-MSCs. We can thus conclude that AD-MSCs were more efficient than BM-MSCs for improving bone quality in type-I OI.

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  • IPEN-DOC 28449

    IZQUIERDO, J.; SILVA, R.M.P. da ; MILAGRE, M.X. ; COSTA, I. ; BETANCOR-ABREU, A.M.; SOUTO, R.M.. Microelectrochemical evaluation of severe localized corrosion sites developing on third-generation aluminium alloys. In: CURRENT TRENDS IN ELECTROCHEMISTRY; MEETING OF THE ELECTROCHEMISTY GROUP OF THE SPANISH ROYAL SOCIETY OF CHEMISTRY, 41st; FRENCH‐SPANISH ATELIER/WORKSHOP ON ELECTROCHEMISTRY, 1st, July 6-9, 2021, Paris, France. Abstract... 2021. p. 89-89.

    Abstract: Third-generation aluminium-copper-lithium alloys exhibit attractive mechanical properties, in particular light-weight and significant strength. However, the developed microstructure often results in severe localized corrosion (SLC) sites with fast in-depth pit propagation accompanied by H2 evolution.1 Such phenomena stem from a strong galvanic coupling, mainly established between Fe- and Cu-rich particles and the surrounding matrix. As a result, strong concentration and pH gradients develop throughout the aluminium surface, determining the local breakdown of the passive regime eventually provided by aluminium oxides and corrosion products. Understanding the development of such distributions is key to outline appropriate strategies for the prevention of fast degradation and materials failure. Scanning Electrochemical Microscopy (SECM) and Scanning Vibrating Electrode Technique (SVET) are capable of providing local information on the distribution of active sites and the presence of reactive chemical species. SVET has previously demonstrated the formation of gas bubbles ascribed to hydrogen evolution (i.e., electro-reduction process) at the anodically-activated sites,2,3; whereas local hydrogen production, oxygen consumption and pH changes are readily accessible using SECM, although with some limitations with regards to the detection of evolving gas.4 The present contribution reports recent advances in the investigation of local degradation phenomena occurring at the surface of Al-Cu-Li alloy AA-2098, as bare material and after friction stir welding. Oxygen consumption over nobler particles acting as cathodic sites, and SLC accompanied with strong acidification and H2 production at the local anodes were observed. The determined pH and concentration gradients allow to progress in the knowledge of the mechanistic aspects involved in the degradation processes on these materials.

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  • IPEN-DOC 28448

    JACOVONE, RAYNARA M.S. ; JESUS, JULIANA M.S. de; SAKATA, SOLANGE K. ; RICARDO, ELIO C.. Uso do Kahoot! como ferramenta avaliativa em um ambiente interdisciplinar e remoto: primeiras impressões. In: CARMO, CAROLINA (Ed.); RANGEL, FERNANDA (Ed.); RIBEIRO, RAPHAEL de A. (Ed.); QUARTO, LUCAS C. (Ed.); SOUZA, THAIS C. de (Ed.) CONGRESSO NACIONAL DE ENSINO CIENTIFICO, 2., 15-18 de julho, 2021, Online. Resumo... Macaé, RJ: Congresse.Me, 2021.

    Abstract: O presente estudo visa apresentar as primeiras impressões observadas após o uso da plataforma on-line Kahoot! como ferramenta avaliativa do processo de aprendizagem ativa da disciplina IPN 0034 – Fundamentos dos Nanomateriais, integrante do conjunto de disciplinas optativas da graduação disponibilizadas no Instituto de Pesquisas Energéticas e Nucleares (IPEN). O curso baseia-se na fundamentação de conceitos aplicados ao estudo de nanomateriais, tais como síntese, caracterização e aplicação dessa tecnologia no âmbito científico e industrial. No ano atual, a disciplina, que ainda está em curso, é ministrada por quatro professores e quatro monitores do Programa de Aperfeiçoamento de Ensino (PAE), com 48 alunos dos seguintes cursos: Bacharelado em Biotecnologia (19%), Engenharia Química (19%), Química (17%), bacharelado em Física Médica (4%), além de alunos de outras Engenharias, Odontologia e Ciências Contábeis. Neste contexto, foram previamente selecionadas, dentro do plano da disciplina, a inserção de ferramentas e estratégias educacionais que buscam promover um aprendizado ativo. A heterogeneidade do público-alvo atribui ao curso um caráter multidisciplinar, além de motivar a atual necessidade de aprimorar a interação professor-aluno em um ambiente remoto. A título de exemplo, a disciplina em estudo propõem o uso de ferramentas como Kahoot! Mentimeter , uso de mapas conceituais e apresentações de posters na plataforma on-line Wonder . Entre as vantagens da plataforma Kahoot!, destaca-se a obtenção do desempenho imediato dos alunos. O questionário foi desenvolvido com questões de múltipla escolha, sendo apenas uma das alternativas correta, sendo aplicado ao término de cada aula, pelos monitores da disciplina. A hipótese que está sendo avaliada, após a execução de cinco aulas, refere-se à observação de que, ao disponibilizar material para consulta/estudo, antes da aula, os alunos tiveram um maior/melhor desempenho no Kahoot! As evidências obtidas até o momento indicam que em aulas que foram apresentadas questões referentes ao conteúdo pré-aula, cerca de 74% a 96% das questões foram respondidas corretamente. Porém, nas aulas sem material prévio, o máximo de acertos foi de 48%. Esses dados consideram a participação de 48 a 44 alunos, sem considerar o tempo para resposta das questões, mas apenas o que foi pontuado como certo e errado. Essa distinção de desempenho aponta para a importância do aluno estudar ou ter um contato prévio com o conteúdo que será dado em sala. Destaca-se que a investigação da efetividade de uma ferramenta no decorrer do curso permite ao professor aprimorar ou, até mesmo, rever suas escolhas didáticas propostas no plano de aula, o qual não deve ser engessado, mas sim dinâmico, em resposta ao grupo de alunos e suas particularidades. Portanto, é possível identificar que a aplicação de material pré-sala e o uso do Kahoot! está permitindo avaliar de forma efetiva o desempenho dos alunos, oferecendo indicadores para avaliar também as práticas do professor na disciplina em questão.

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  • IPEN-DOC 28447

    JACOVONE, RAYNARA M.S. ; JESUS, JULIANA M.S. de; TEIXEIRA, ANTONIO C.S.C.; SAKATA, SOLANGE K. . Screen printed electrode modified with reduced graphene oxide obtained by ɤ radiation for levonorgestrel detection. In: FRONTEIRAS EM ELETROQUÍMICA E ELETROANALÍTICA, 2.: AVANÇOS REALIZADOS POR JOVENS MULHERES CIENTISTAS, 11-12 de fevereiro, 2021, Online. Resumo... Rio de Janeiro, RJ: Universidade Federal do Rio de Janeiro, 2021. p. 131-132.

    Abstract: INTRODUCTION Screen printed electrodes (SPE) have attracted attention due to their fast and accurate response, high sensibility, specificity, and portable platforms. To increase their electrical carrier mobility and sensibility, the working electrode surface has been modified using reduced graphene oxide (rGO) [1]. In the present work, gamma radiation reduced Graphene Oxide (GO) to produce rGO in a sustainable method that avoids toxic reagents and the production of hazardous chemical residues [2]. Levonorgestrel (LNG) is a synthetic contraceptive hormone of worldwide concern, being harmful to aquatic organisms, even at low concentrations, e.g., 0.024 nmmol L-1 [3]. METHODOLOGY Reduced graphene oxide was obtained using GO (10 mg mL-1) dispersed in a water/isopropanol. The sample was irradiated in the Multipurpose Gamma Irradiation Facility at CETER/IPEN/CNEN-SP, at a dose rate of 10 kGy h-1 and 80.0 kGy in inert conditions. The SPE was modified by drop casting 10 μL of the rGO solution and dried at room temperature. The rGO-SPE was characterized by Raman spectroscopy and the electrochemical behavior of LNG was investigated using cyclic voltammetry (CV) in phosphate buffered saline (PBS) medium (pH 7.0) within the oxidation window 0.0-1.0 V and 25 mV s-1 (Fig. 1). RESULTS The Raman spectrum showed D (1.347 cm-1) e G (1.594 cm-1) bands for both rGO-SPE and SPE. The ID/IG ratio was 0.85 and 1.40 for SPE and rGO-SPE, respectively. For rGO-SPE, cyclic voltammograms showed a reversible behavior in K4Fe(CN)6 [2 mmol L-1] and in the presence of LNG [6410-9 mol L-1], anode inflection was observed at 0.6 V, associated with the non-reversible oxidation reaction of LNG. CONCLUSIONS The surface of the rGO-SPE was uniform, being the ID/IG ratio for the covered electrode higher than that exhibited by the uncovered one. This electrode presented electrochemical response to LNG, even at low concentrations, thus proving its application as an electrochemical sensor for the LNG hormone.

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  • IPEN-DOC 28446

    TAVARES, P.V.S. ; RODRIGUES JUNIOR, O. ; CAMPOS, L.L. . Application of CT optical system for dose evaluation of Fricke gel solution. In: ENCONTRO DE FÍSICA DO NORTE E NORDESTE, 35., 18-20 de outubro, 2021, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2021.

    Abstract: Objective: This work aims to evaluate the Fricke gel solution as a method for three-dimensional dosimetry using an equipment of optical computed tomography VISTA 16. Purpose: The technique of optical computed tomography has similarities with X ray CT, the difference is that optical CT utilizes visible light as the photon source. Both optical and X ray CT works with attenuation data acquired at various views through the object to be imaged. Optical computed tomography was developed as an alternative method for evaluating gel solutions for three-dimensional dosimetry [1]. The evaluation by optical computed tomography is performed by measuring the solution before and after irradiation. The application of mathematical algorithm of inverse problems is used for images reconstruction. The reconstructed images are used to evaluate the attenuation variation between before and after irradiation [2]. There is a correlation between attenuation variation and the dose deposited in material. The Fricke gel solution has been changed to become a radiochromic solution, i.e., have the property of undergoing changes in optical density as a function of the deposited dose. The xylenol orange added to the Fricke gel solution becomes a ferric ions (Fe3+) indicator, resulting from the oxidation of ferrous ions (Fe2+) radiation induced [3]. Materials and Methods: For this work it was proposed a solution Fricke gel modified with reduce in xylenol orange concentration for specified use in optical CT. The Fricke gel solution samples were irradiated with 60Co gamma radiation in a Gammacell equipment with isotropic irradiation capacity. Results: The evaluation in optical CT equipment VISTA 16 results images with alteration in pixel values that correspond to attenuation variation. In images it was possible verify the dose distribution uniformly that corresponds to the isotropic irradiation method. Conclusions: The Fricke gel solution evaluated in optical CT shows a uniformity of the dose that was applied in the solution, being feasible to be studied for irradiation in radiotherapy equipment looking for its use in treatment planning.

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  • IPEN-DOC 28445

    ASSUNCAO, ISRAEL; NETO, ALBANO; MOURA JUNIOR, RENALDO; PEDROSO, CASSIO; SILVA, IVAN; FELINTO, MARIA C. ; TEOTONIO, ERCULES; MALTA, OSCAR; BRITO, HERMI. The influence of the odd-even effect of aliphatic dicarboxylate ligands on the photoluminescent properties of europium complexes. In: PREQUEL SYMPOSIUM ON ADVANCED TECHNOLOGIES AND MATERIALS, October 13-15, 2020, Online. Abstract... 2020.

    Abstract: Eleven [Eu2(L)3(H2O)x]·y(H2O) complexes with aliphatic dicarboxylate ligands (L: OXA, MAL, SUC, GLU, ADP, PIM, SUB, AZL, SEB, UND, and DOD, where x=2–6 and y=0–4) were synthesized and characterized by elemental and thermal analysis, FTIR spectroscopy and powder X-ray diffraction. The obtained data confirms the ligand to metal ratio, the hydration degree, the coordination mode and that the complexes are crystalline. The oddeven effect was observed for the final dehydration temperature of the Eu3+ complexes (Fig. 1). Moreover, the effect was also observed in the experimental and theoretical photoluminescent properties such as the intensity parameters, Ω2 and Ω4 (Fig. 2) and the emission intrinsic quantum yield, QLnLn (Fig. 3) of the Eu3+ complexes. The odd-even effect on the Ω2 and Ω4 values could be explained by using an extension of the dynamic coupling mechanism, herein named the ghost-atom (GA) model, in which the long-range polarizabilities (α*) were determined by simulating the presence of a ghost atom in the middle of each ligand carbon chain and the localized molecular orbital approach. The GA approach is an extension of the Bond Overlap Model (BOM) [1].

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  • IPEN-DOC 28444

    FRANCISCO, LEONARDO ; FELINTO, MARIA ; BRITO, HERMI. Development of rare-earth-doped hybrid materials towards luminescence enhancement. In: PREQUEL SYMPOSIUM ON ADVANCED TECHNOLOGIES AND MATERIALS, October 13-15, 2020, Online. Abstract... 2020.

    Abstract: The rapid growth on the development of rare-earth-doped luminescent materials has been drawing attention due to complex energy converting systems that can be structurally engineered to tune absorption and emission wavelengths, outlining new materials and applications for photonics. [1, 2] In this scenario, this work presents the development of rare-earth-doped strontium aluminate phosphors prepared by the Pechini method and modified with 3-aminopropyltrimethoxysilane via microwaveassisted synthesis, integrating a silica network with rare-earth β-diketonate complexes in order to enhance the absorption section and promote energy-transfer processes within the system. The prepared materials were analyzed by X-ray powder diffraction, where a characteristic monoclinic SrAl2O4: Eu2+, Dy3+ phase with crystallite size around 30 nm was observed. Several structural changes attributed to surface modification were also noted. Scanning Electron Microscopy images and Energy- Dispersive X-ray Spectroscopy results revealed the expected surface alteration effects, as well as the element mapping throughout the samples. Standard UV-Vis and Vacuum-UV Luminescence Spectroscopies were also performed. The optical behavior of the synthesized materials was characterized by green Eu2+ emission assigned to the 4f65d1→4f7(8S7/2) interconfigurational transition under near-ultraviolet excitation alongside narrow 4f-4f transitions of non-reduced Eu3+. Furthermore, in functionalized samples, S0→Sn transitions attributed to β-diketonate ligands were also observed, unveiling an increasing absorption section under ultraviolet light. Finally, it was noted a significant increase in the persistence decay time under near Band-Gap excitation in modified materials, suggesting interactions between the inorganic host-matrix, the silica network, and the β-diketonate complexes.

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  • IPEN-DOC 28443

    FELINTO, M.C.F.C. ; ALI, B. ; FRANCISCO, L.H.C. ; BLOIS, L.; BRITO, H.F.; MALTA, O.L.; TEOTONIO, E.E.S.. Synthesis and luminescent properties of three new and bright Eu - tta compounds modified on α-carbon for use as biological markers. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 19th, July 26-30, 2021, Changchun, China. Abstract... 2021.

    Abstract: Three smarts luminescent Eu3+ complexes (Eu1 = Eu(tta-ester)3phen 1, Eu2 = Eu(tta- NH2)3phen 2, Eu3 = Eu(tta-COOH)3phen, were synthesized by using phenanthroline as the neutral ligand and Cα modified 2-thenoyltrifluoroacetonate and as the anionic ligand. All the Eu(III) complexes were structurally characterized by spectroscopic methods. Photoluminescence (PL) emission spectra of Eu complexes showed red color emission in the solid state. These materials were analyzed by X-ray diffraction, scanning electron microscopy and by energy dispersive, ultraviolet–visible spectroscopy, luminescence and vacuum ultraviolet–ultraviolet spectroscopies.The spectra show several sharp emission bands ranging from 450 to 750 nm due to the 4f– 4f transition from the excited state 5D0 to the low-lying multiple level 7FJ (J = 0, 1, 2, 3 and 4) of the Eu3+ ion. The five main sharp emission peaks were observed at wavelengths of c.a. 579, 591, 613, 653 and 702 nm, which are attributed to the f–f electronic transitions of the Eu(III) ion (5D0 → 7F0, 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4, respectively). These complexes were evaluated also in terms of high energy.VUV-UV emission spectra present the 5D0→7F2 the transition dominating the spectrum under excitation at higher energies (Fig.1).

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  • IPEN-DOC 28442

    FRANCISCO, L.H.C. ; MOREIRA, R.P. ; BRITO, H.F.; TEOTONIO, E.E.S.; MALTA, O.L.; FELINTO, M.C.F.C. . Luminescence of Eu(tta)3(N-picNO)2 (N=2, 3 and 4) doped PMMA films under Synchrotron radiation. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 19th, July 26-30, 2021, Changchun, China. Abstract... 2021.

    Abstract: Since their discovery, trivalent lanthanide β-diketonate complexes often stand out among luminescent coordination compounds [1]. Thus, the incorporation of such complexes into polymeric materials proposes increased photostability, optical quality, and processing conditions [2]. In this work, we prepared and doped the luminescent Eu(tta)3(N-picNO)2 (N=2, 3 and 4) complexes into Poly(methyl methacrylate) (PMMA) films via the solvent casting method, yielding transparent materials under visible light. These amorphous materials (XRD) presented considerable thermal stability up to 300°C (TGA), and their spectroscopic properties with ancillary ligand exchange were investigated by luminescence spectroscopy in the UV-Vis and Vacuum-UV energy range by synchrotron radiation. Mainly, Eu3+ transitions (5D0→7F0-4) were observed in the emission spectra for all compounds, with intense monochromatic-like red (614 nm) emission (Fig. 1), indicating efficient intramolecular energy transfer. Experimental intensity parameters and quantum yields were also determined, where it is seen the influence on the positioning of the methyl group in the luminescence efficiency.

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  • IPEN-DOC 28441

    MOREIRA, R.P. ; FRANCISCO, L.H.C. ; BRITO, H.F.; MALTA, O.L.; TEOTONIO, E.E.S.; FELINTO, MARIA C.F.C. . Eu3+-doped BaMO4 (M: W or Mo) luminescent materials for lighting applications prepared by coprecipitation method. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 19th, July 26-30, 2021, Changchun, China. Abstract... 2021.

    Abstract: This work presents the development and investigation of the structural, spectroscopic, and electronic properties of Eu3+-doped BaMO4 (M: W or Mo) compounds obtained by the coprecipitation method, at room temperature, targeting applications in phosphor-converted Light-Emitting Diode (pc-LEDs) lighting devices [1,2]. A systematic study was performed to determine optimal doping concentrations in order to obtain high-intensity monochromatic-like luminescence with efficient lanthanide quantum yield for red light emission. Structural analysis by X-Ray Powder Diffraction showed a stable characteristic scheelite-type structure for all of the studied compounds, with no phase segregation, as confirmed by Rietveld Refinement, whereas average crystallite size was estimated to be about 30 nm. Morphology and elemental distribution were probed by Scanning Electron Microscopy coupled with Energy dispersive X-ray spectroscopy, where homogeneous europium distribution was identified even at high doping concentrations (up to 10% molar). The optical behavior of the prepared materials was studied by Diffuse Reflectance Spectroscopy and Luminescence Spectroscopy in the UV-Vis range, displaying characteristic red emission, together with the nephelauxetic effect associated with spectral red-shifts attributed to structural distortions around the Eu3+ ion and significant (LMCT) contribution. The intensity parameters Ω2,4 and lanthanide quantum yield QLn Ln of all Eu-doped materials were also determined. Furthermore, the CIE color diagram was investigated, showing the rate of greenish-blue host matrix contribution ([WO4]2- or [MoO4]2-) and Eu3+ luminescence in different compounds.

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  • IPEN-DOC 28440

    PARRA, DUCLERC F. ; MARCHINI, LEONARDO G. ; FELINTO, MARIA C. ; BRITO, HERMI F.. Photoluminescent properties of the polyamide /Eu3+ β-diketonate complex for optical application. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 19th, July 26-30, 2021, Changchun, China. Abstract... 2021.

    Abstract: The Eu3+ complex precursor, the polymeric (PA) optical marker and the plastic luminescent films obtained were characterized by infrared spectroscopy (FTIR), X-Ray diffractometry (DRX), emission spectroscopy, and thermogravimetry (TGA). The emission spectra of the Eu3+–tta complex doped in the PA exhibited the characteristic bands arising from the 5D0 → 7FJ transitions (J = 0-4). High values of the Ω2 intensity parameter were obtained, indicating the hypersensitive character of the 5D0 → 7F2 transitions and the Eu3+ ions are in a polarizable chemical environment. The high values of the Ω4 parameter confirm the basicity of the oxygen donor from the polymer. Lifetime measurement suggests that doped Eu3+ ion has higher luminescence efficiency in the film than hydrated complex. The emission quantum efficiencies (η) and the highest value are observed in the system PA:[Eu(tta)3(H2O)2] 5%. The PA-optical marker resulted a luminescent plastic film, with high stability when processing.

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  • IPEN-DOC 28439

    ASSUNCAO, I.P.; BRITO, H.F.; FELINTO, M.C.F.C. ; TEOTONIO, E.E.S.; MALTA, O.L.. A new series of luminescent tetrakis Ln3+-complexes with α-substituted β-diketonate ligands and Na+ as countercation. In: INTERNATIONAL CONFERENCE ON LUMINESCENCE, 19th, July 26-30, 2021, Changchun, China. Abstract... 2021.

    Abstract: The Ln3+ β-diketonate coordination compounds have received growing attention in the past few years, mainly due to their inherent huge variety of applications. The tris and tetrakis species have also been widely used as an emitting layer in organic light-emitting diodes (OLEDs) due to their high intensity and monochromatic emission. The tetrakis complexes usually present improved properties such as thermal and chemical stabilities, besides higher luminescence lifetimes than its correspondent tris complexes. Moreover, the commonly hydrated tris Ln3+-complexes show a luminescence quenching due to vibronic coupling between H2O molecules and the Ln3+ principal emitting levels (e.g., 4G5/2, 5D0, 5D4, 4F9/2 and 1G4 of the Sm3+, Eu3+, Tb3+, Dy3+ and Tm3+ ions, respectively) [1]. The acetylacetone (2,4-pentanedione) ligand, Hacac, is one of the most extensively used and studied β-diketonate ligands, especially for the Tb3+ ion. Nevertheless, the α-substituted Ln3+ β-diketonate complexes are relatively scarce in the literature [2]. Hence, this work reports the synthesis, characterization, and photoluminescent study of a new series of tetrakis coordination compounds containing the α-substituted β-diketonates 3-chloro acetylacetone (Cl-acac), presenting the general formula Na[Ln(Cl-acac)4], where Ln: Sm3+, Eu3+, Tb3+, Dy3+, and Tm3+. All complexes were characterized by elemental analysis, complexometric titration, thermal analysis, infrared absorption spectroscopy (FTIR), and X-ray powder diffraction (XPD). The Ln3+ complex photoluminescent properties (Figure 1) as well as the experimental intensity parameters (Ω2,4) of the Eu3+ were determined.

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