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Effect of wood sawdust-derived biochar as a substrate component on leachate water quality
2025 - LIMA, DANIELE de A.V.; STELLATO, THAMIRIS B.; ULRICH, JOAO C.; SILVA, DANILO L.C. e; REZENDE, FABIANA A. de; FUNGARO, DENISE A.
This study investigated the effect of biochar addition (14% w/w) on the concentration of nutrient ions present in the leachate from a commercial green roof substrate after contact with rainwater. Biochar sample was produced from wood sawdust at 450 ˚C via slow pyrolysis. The sawdust biochar was characterized by physico-chemical and hydraluic prosperties and techniques including X-ray fluorescence, Fourier transform infrared spectroscopy, X-ray diffraction, Raman and differential thermal analysis. The physical and chemical properties of green roof substrate were also determined. The biochar effectively reduced the total amount of nitrate, sulfate, and phosphate in the leachates relative to the substrate alone but did not show a significant effect on ammonium leaching. The results indicated that wood sawdust-biochar has appropriate characteristics to be applied as a component of substrates, as it has a porous structure and adsorption capacity, as well as adequate physical-hydric properties. In addition, the management of biochar obtained from agricultural waste can contribute to the achievement of the Sustainable Development Goals when used in sustainable alternatives such as green roofing.
Ciências nucleares e sociedade
2025 - LEVY, DENISE; VILLAVICENCIO, ANNA L.
A tecnologia nuclear é uma temática controversa para grande parte da sociedade. A percepção pública sobre o risco da radiação ionizante é impactada pela falta de informação correta e desconhecimento sobre danos a longo prazo à saúde humana e ao meio ambiente. A disseminação da informação científica de qualidade é crucial para o desenvolvimento nacional, sobretudo às novas gerações, futuros tomadores de decisão em nossa sociedade. O presente artigo discute a experiência dos autores no desenvolvimento de habilidades-chave necessárias para uma eficaz comunicação das ciências nucleares para professores do Ensino Básico, multiplicadores do conhecimento e formadores de opinião. O estudo envolveu pesquisas de aceitação pública e ações de comunicação, incluindo a realização de eventos e a produção de materiais paradidáticos. O ano de 2017 apontou possibilidades transformadoras, com políticas públicas, que favoreceram a popularização da ciência, e mudanças curriculares, possibilitando a inserção de temas transversais de forma interdisciplinar. Nesse contexto, o artigo discute a divulgação científica, para além da transmissão de dados e fatos, como um processo complexo e cuidadoso que exige um conjunto especializado de habilidades que vão além da expertise científica. Os autores apresentam os conjuntos de ações iniciadas em 2017 e seus desdobramentos, que exigiram o desenvolvimento de soluções educacionais em quantidade e qualidade, em conformidade com uma sociedade de constantes atualizações tecnológicas e rápidas mudanças.
Development of web software for determining element concentrations based on the k0 standardization method of neutron activation analysis
2025 - KAISER, THIAGO J.S.; DIAS, MAURO da S.; SEMMLER, RENATO
This work presents the development and validation of the K0- WEB software, dedicated to the determination of elemental concentrations based on the k₀-standardization method of Neutron Activation Analysis (NAA). This method, recognized for its high accuracy, enables multielement analyses of samples without the need for standards, relying on the precise characterization of facilities and the use of nuclear parameters such as k0- factors, Q₀, and decay constants. The system stands out for its innovative web-based architecture and the automation of nuclear data import, providing originality and operational autonomy. The software integrates essential corrections—such as cascade summing, geometry factor, and allows step-by-step monitoring of calculations, interactive visualization, and report generation. The validation of K0-WEB was carried out by comparing its results with those of the K0-IPEN program, previously submitted to an international intercomparison exercise of the International Atomic Energy Agency (IAEA), ensuring the reliability of the new system. The experimental part employed standardized data from IAEA-TECDOC-2026. Concentration, efficiency, and thermal and epithermal flux parameter calculations were performed according to methodologies established in the literature, with emphasis on the bare triple monitor method and the cadmium ratio method. Additionally, an uncertainty analysis based on error propagation and covariance matrix was applied. The results demonstrated the validation of K0-WEB, and it can be concluded that K0-WEB represents an innovative, accurate, and efficient solution for application in NAA laboratories.
Conversion of solid waste from electricity cogeneration into slow-release fertilizer
2025 - IZIDORO, JULIANA; MONTEIRO, LUCILENA R.; STELLATO, THAMIRIS B.; COTRIM, MARYCEL E.B.; FUNGARO, DENISE
Sugarcane bagasse from the sugar and ethanol industry is generated in large quantities in Brazil and is typically burned in plant boilers to produce electricity in the so-called cogeneration process. After combustion, the remaining solid waste, known as sugarcane bagasse ash (SCA), does not have many applications and is usually discarded around the industries. SCA can be converted into zeolites, which can be applied as support for the slow-release fertilizers, treatment of industrial effluents, carbon sequestration and capture, among others. Therefore, the present study aimed to obtain high-purity type A zeolite from SCA with NH4+ incorporated into its structure and evaluate its application in agriculture. An SCA sample generated in a power cogeneration plant located in São Paulo, Brazil, was used to synthesize zeolite type A (ZASC), which was characterized in terms of chemical composition (XRF), mineralogical composition (XRD), and morphology (SEM). Ammonium ion was incorporated into ZASC by ion exchange. The presence of NH4+ in the zeolite structure was confirmed by using the Fourier Transform Infrared Spectroscopy (FTIR) technique. The NH4+ modified zeolite was labelled as ‘ZASCN1’. The amount of NH4+ released from ammonium-modified zeolite (ZASCN1) over time was evaluated through contact with water and saline solution in a static system and the concentration was measured by ion chromatography. Results showed that ZASCN1 can release a greater amount of nutrients in saline solutions when compared to water. In addition, both curves showed that the release of NH4+ occurred slowly and steadily for more than 1 month. Therefore, it can be concluded that the sugarcane industry has many possibilities for research, as well as the development and generation of products with market competitiveness, as the slow-release fertilizers, following the principles of the circular economy.
Assessment of potentially toxic elements in sediment cores from reservoirs in the Upper Tiete River Basin, Brazil
2025 - GONCALVES, P.N.; DAMATTO, S.R.; SOUZA, J.M.; LEONARDO, L.
This study evaluated concentrations of potentially toxic elements (PTEs)—As, Sb, Co, Cr, Zn, U, and Th—in sediment cores from the Jundiai and Taiaçupeba reservoirs in the Upper Tiete Water Basin, Sao Paulo, Brazil. These reservoirs are vital for supplying water to the São Paulo metropolitan area but face risks from agricultural and industrial activities. The research aimed to determine whether PTE enrichment in sediments is due to natural or anthropogenic factors, assess the influence of sediment geochemistry and grain size, and evaluate risks to public health and biota. Granulometric analysis and enrichment factors were used to interpret the results, with As, Cr, and Zn compared to sediment quality guidelines. Significant Zn contamination was found in the Taiaçupeba reservoir, exceeding the Probable Effects Level (PEL), suggesting mining-related contamination. This highlights the need for further research on Zn’s spatial distribution, ecological risks, and bioavailability in the Taiaçupeba reservoir. Conversely, Sb, Co, Cr, U, and Th were linked to natural processes. Arsenic showed a local geologic anomaly in both reservoirs. This research emphasizes the importance of geochemistry as a critical tool for interpreting PTEs in trace element environmental monitoring. Geochemical parameters, including Hf, Ta, Sc, and K, and rare earth elements, were essential for understanding sedimentary dynamics and anthropogenic impacts. This approach enhances the effectiveness of PTE impact assessments and can be applied to other dam reservoirs worldwide.
Demonstration of a governamental initiative through the installation of photovoltaic modules in social projects
2025 - FRANCO, RENNAN de A.; CONTI, THADEU das N.
In 2022, solar energy generation through photovoltaic modules saw a remarkable 26% increase, reaching nearly 1300 TWh, solidifying its status as the renewable energy source with the highest annual growth rate. This trend has sparked substantial investments from major European powers, the United States, and China (International Energy Agency - IEA 2022). This article aims to assess the feasibility of the Brazilian government implementing photovoltaic modules in low-income and peripheral households to align with global trends and mitigate energy costs during dry periods. Data from photovoltaic energy companies in Brazil and abroad were compiled for analysis, considering various module types and efficiencies. The study, conducted using Python for data interpretation through tables and graphs, concluded that solar irradiation is uniformly distributed across the country, making the project viable nationwide. Calculations showed profitability for a single household, with an estimated implementation cost of R$21,000.00, achievable after 24 years, yielding an approximate profit of R$5,640.00 over the module's 30-year lifespan. This underscores the viability of a profitable government initiative aligned with UN Sustainable Development Goal 7, reducing CO2 emissions from thermal power plants and cutting electrical energy costs.
Cl-Doped ZnO nanoparticles with enhanced photocatalytic activity via selective surface lixiviation
2025 - FORTES, GUSTAVO M.; SILVA, ANDRE L. da; RAMOS, BRUNO; BETTINI, JEFFERSON; FONSECA, FABIO C.; GONCALVES, RENATO V.; RODRIGUES JUNIOR, ORLANDO; GOUVEA, DOUGLAS
Selective surface lixiviation is commonly employed to quantify dopants segregated on the surface of nano oxides. In this study, we utilize this method as a strategy to enhance the photocatalytic activity of Cl-doped ZnO. Diffuse reflectance spectroscopy revealed that the dopant was not dissolved in a solid solution, and surface defects were confirmed through color measurements using the CIE Lab* system and electron paramagnetic resonance (EPR). X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) confirmed the presence of ZnCl2 on the surface of doped ZnO samples. STEM EDS elemental mapping revealed an ∼6 nm-thick Cl-enriched surface layer at the edge of the ZnO nanoparticle. The selective lixiviation method effectively removed the Cl dopant from the surface of ZnO nanoparticles, as demonstrated by FTIR-DRIFT, while preserving the additive in the grain boundaries (GBs). This process mitigated chloride poisoning during photocatalysis by removing soluble Cl and enhancing electrical conductivity through GB segregation. These synergistic effects contributed to the improved photodegradation of the model contaminant acetaminophen, positioning lixiviated Cl-doped ZnO nanoparticles as highly effective for the target application of acetaminophen degradation.
Dysregulated autoantibodies targeting AGTR1 are associated with the accumulation of COVID-19 symptoms
2025 - FONSECA, DENNYSON L. M.; JAPEL, MAJ; GYAMFI, MICHAEL A.; FILGUEIRAS, IGOR S.; BAIOCHI, GABRIELA C.; OSTRINSKI, YURI; HALPERT, GILAD; LAVI, YAEL B.; VOJDANI, ELROY; SOUSA, THAYNA S.; USUDA, JULIA N.; SILVA, JUAN C.S. e; FREIRE, PAULA P.; NOBILE, ADRIEL L.; ADRI, ANNY S.; BARCELOS, PEDRO M.; CORREA, YOHAN L.G.; VALE, FERNANDO Y.N. do; LOPES, LETICIA O.; SCHMIDT, SOLVEIG L.; WANG, XIAOQING; VAHLDIECK, CARL; FELS, BENEDIKT; SCHIMKE, LENA F.; MIRANDA, GUSTAVO C.; HIRATA, MARIO H.; AKHAN, TAJ A.; YU, YEN-REI A.; DALMOLIN, RODRIGO J.S.; AMITAL, HOWARD; VOJDANI, ARISTO; DIAS, HAROLDO D.; NAKAYA, HELDER; OCHS, HANS D.; SILVERBERG, JONATHAN I.; ZIMMERMAN, JASON; ZYSKIND, ISRAEL; ROSENBERG, AVI Z.; FORSTER, KAI S.; HEIDECKE, HARALD; CATAR, RUSAN; MOLL, GUIDO; HACKEL, ALEXANDER; VIHROG, KRISTINA K.; SHOENFELD, YEHUDA; RIEMEKASTEN, GABRIELA; AKBARZADEH, REZA; MARQUES, ALEXANDRE H.C.; MARQUES, OTAVIO C.
Coronavirus disease 2019 (COVID-19) presents a wide spectrum of symptoms, the causes of which remain poorly understood. This study explored the associations between autoantibodies (AABs), particularly those targeting G protein-coupled receptors (GPCRs) and renin‒angiotensin system (RAS) molecules, and the clinical manifestations of COVID-19. Using a cross-sectional analysis of 244 individuals, we applied multivariate analysis of variance, principal component analysis, and multinomial regression to examine the relationships between AAB levels and key symptoms. Significant correlations were identified between specific AABs and symptoms such as fever, muscle aches, anosmia, and dysgeusia. Notably, anti-AGTR1 antibodies, which contribute to endothelial glycocalyx (eGC) degradation, a process reversed by losartan, have emerged as strong predictors of core symptoms. AAB levels increased with symptom accumulation, peaking in patients exhibiting all four key symptoms. These findings highlight the role of AABs, particularly anti-AGTR1 antibodies, in determining symptom severity and suggest their involvement in the pathophysiology of COVID-19, including vascular complications.
Benefits of incorporating Dy–Cu alloy via the grain boundary diffusion process in recycled magnets
2025 - DIAS, M.B.S.; SHIMIZU, G.Y.S.; AZEVEDO, L.L.; RODRIGUES JUNIOR, D.L.; MACEDO, W.C.; ANTUNES, L.F.; LOPES, L.U.; WENDHAUSEN, P.A.P.; FARIA, R.N.; SANTOS, C.A.L.; PASTRIAN, F.A.C; LANDGRAF, F.J.G.
Nd-Fe-B magnets are a critical material for the green energy transition. However, price volatility makes the supply chain fragile, which makes the recycling process an alternative to reduce dependence on raw materials. Unfortunately, the recycling process introduces oxygen into the magnet, getting worse magnetic properties. Thus, this article studies the effects of the grain boundary diffusion (GBD) process with Dy–Cu slurry on the magnetic and corrosion properties of recycled magnets. As expected, the recycling process reduced the coercivity from 1350 kA/m to 850 kA/m and also decreased the coercivity thermal stability (β) from −0,530 %/°C to of −0.590 %/°C. The introduction of oxygen reduces the amount of the Nd-rich phase, preventing the formation of a grain boundary phase. However, since Nd oxides are more electrochemically stable than the Nd-rich phase, an improvement in corrosion resistance occurred. Regarding the GBD performed at 900 °C increases the coercivity to 1290 kA/m and achieves higher thermal stability (β = −0.54 %/°C) compared to recycled magnets. During GBD, a Dy-rich shell composed of (Dy + Nd + Pr)2Fe14B was formed around the Φ phase grains. Since Dy locally increases the magnetic anisotropy on the surface of the Φ phase grains, a higher magnetic field is required to nucleate an opposite magnetic domain. Moreover, the recycled magnet treated with GBD at 900 °C exhibits higher corrosion resistance than End-of-Life magnets. In summary, the GBD could be an alternative to partially recover the coercivity of recycled magnets, resulting in a magnet with higher corrosion resistance than End-of-Life magnets.
Dental adhesive protection against development of noncarious cervical lesions
2025 - DENUCCI, G.C.; LIMA, L.C.; EKERT, G.J.; SILVA, F.; SCARAMUCCI, T.; SOCHACKI, S.; HARA, A.T.
OBJECTIVE: This study aimed to verify whether dental adhesives prevent noncarious cervical lesion (NCCL) development in an in vitro simulation model based on abrasive/erosive challenges. METHODS AND MATERIALS: Extracted human premolars were randomly assigned to one of three treatments (n=16): 1. reference adhesive (Clearfil SE, Kuraray Co., Ltd., Chiyoda City, Tokyo, Japan); 2. experimental adhesive (10 wt% [percentage by weight] beta-tricalcium phosphate nanoparticles); 3. negative control (no treatment). After treatment, specimens were submitted to 11 episodes of 18 hours of acid exposure (1% citric acid solution-0.052 molar (M), pH ~2.5) interspersed by toothbrushing abrasion. Three-dimensional images of teeth were captured at baseline and after 5000, 10,000, 15,000, 35,000, and 55,000 toothbrushing strokes using an intraoral scanner. Tooth wear (mm3) was calculated after each toothbrushing period by scan superimposition. Lesion angle was measured, and shape classified. Data were analyzed using analysis of variance (ANOVA) and Fisher Protected Least Significant Difference (PLSD) tests (α=0.05). RESULTS: Tooth wear increased with toothbrushing strokes overall (p<0.001) and within each treatment (p<0.05) except between 10,000 and 15,000 strokes (p=0.24). Reference had less tooth wear than control overall (mean difference [95% CI]: 0.68 [0.20,1.15], p=0.008) and for all toothbrushing periods (p<0.05) except at 55,000 strokes (0.54 [-0.38,1.46], p=0.25). Reference had less tooth wear than experimental overall (0.54 [0.01,1.07], p=0.046) and for 35,000 strokes (0.80 [0.13,1.46], p=0.019). Experimental had less tooth wear than negative control at 5000 and 10,000 strokes (p<0.05). Treatments had no effect on lesion angle (p=0.52). At 55,000 strokes, reference had more flat-shaped lesions than experimental (p<0.001) and negative control (p<0.001), but experimental and negative control were not different from each other (p=1.00) having more striated lesions. CONCLUSION: Adhesives showed some degree of protection against NCCL development at early stages; however, reference had longer-lasting protection than experimental.
Development and performance of a low-cost, solid-state, thermal neutron sensor with a 10B converter
2025 - COSTA, P.; WEAVER, J.L.; RAELE, M.P.; PRITCHARD, K.; LEAO, J.B.; DOMIENIKAN, C.; MALISZEWSKYJ, N.C.; SILVA, F.S. da; PEREIRA, W.W.; GENEZINI, F.A.
This study demonstrates the construction and operation of a portable, solid-state thermal neutron sensor that utilizes a photodiode coated with a thin layer of boron-10 (10B). The boron layer was created using pulsed laser deposition and analyzed with neutron depth profiling (NDP) and scanning electron microscopy (SEM). The sensor's response to both thermal and cold neutrons was evaluated under varying neutron fluence rates. Additionally, the impact of the angles between the neutron beam and the sensor surface was examined. SEM results showed a porous 10B film structure, while NDP indicated a nearly uniform distribution of the isotope throughout the film. The electronic signal generated by the sensor exhibited a linear response to neutron fluence rates. However, the measured intrinsic efficiencies were lower than those of commercially available gas-phase detectors, with thermal neutrons yielding an efficiency of (1.17 ± 0.01) % and cold neutrons at (1.78 ± 0.01) %. Potential design upgrades that could increase the sensor's efficiency in the future are also discussed.
Advancements in radiation-induced grafted anion-exchange membranes
2025 - BARBOSA, ANDREY S.; BIANCOLLI, ANA L. G.; SANTOS, BIANCA P.S.; BONVENT, JEAN-JACQUES; HERMIDA-MERINO, DANIEL; SANTIAGO, ELISABETE I.
Manufacturing anion-exchange membranes (AEMs) with high durability is a current challenge for low-temperature alkaline fuel cells. In this work, a series of AEMs based on high-density polyethylene (HDPE) is synthetized by radiation-induced grafting (RIG) method considering various pre-irradiation conditions, such as temperature and atmosphere. The AEMs are extensively characterized, including assessments of the degree of grafting (DoG), ion-exchange capacity (IEC), water absorption properties, and hydroxide conductivity. Additionally, their molecular structure and thermal and mechanical properties are evaluated. Techniques, such as atomic force microscopy (AFM) and synchrotron small angle x-ray scattering (SAXS), are employed for analysis of AEMs morphology. Finally, the AEMs are applied in an H2-O2 anion-exchange membrane fuel cell (AEMFC) and subjected to a short-term stability test. Among the tested AEMs, the one pre-irradiated at low temperature (−10 °C) and air atmosphere exhibits excellent AEMFC performance of 2.1 W cm−2. This sample possesses high OH− conductivity of 208 mS cm−1 at 80 °C, and the stability test shows a conductivity loss of −0.06 % h−1 during 100 h under reduced relative humidity (80 %). Applying an accurate protocol for controlling pre-irradiation parameters can effectively reduce the irradiation degradation effects.
Comparison of constituent intermetallic particles in different aluminium alloys
2025 - ARAUJO, JOAO V. de S.; COSTA, ISOLDA; ZHOU, XIAORONG
This study quantitatively evaluates the variation in the distribution, density, size, and chemical composition of constituent intermetallic particles (IMPs) in different commercial high strength aluminium alloys, including Al-Cu-Mg (AA2024-T3), Al-Cu-Li (AA2198-T8/T851), and Al-Mg-Zn (AA7475-T761) alloys. It is observed that the AA2024-T3 alloy is characterized by three primary types of IMPs (Al-Cu-Mg, Al-Cu-Fe-Mn, and Al-Cu-Fe-Mn-Si) and the highest particle population density. In contrast, the Al-Cu-Li alloys contain a single type of IMP (Al-Cu-Fe), while the AA7475-T761 alloy exhibits the lowest population density of IMPs that are distinguished by varying copper contents.
Arranjo institucional histórico
2025 - ALMEIDA, MADISON C. de; ANDRADE, DELVONEI A. de
O cenário de Defesa sempre propiciou modelos de cooperação internacional, em que práticas políticodiplomáticas associam-se a demandas tecnológicas variadas. O programa FX-2, de aquisição de aeronave de caça para a Força Aérea Brasileira (FAB), originou estudos e a conclusão pelo Gripen NG sueco. Nesse esteio, o trabalho apresentado prospecta o modelo associativo Brasil-Suécia, na ótica dos componentes sociais, políticos, econômicos, principalmente. A introdução ao artigo revela o propósito, enquanto que a seguir é feita breve contextualização, seguida de referenciais teóricos utilizados. A metodologia explicita o cunho descritivo e bibliográfico da produção, culminando com os achados e sua discussão. Nesse diapasão, verifica-se os contextos sociais, culturais, políticos e econômicos da sociedade sueca, em uma revisão histórica, promovendo o entendimento bilateral e a continuidade desde, no escopo da cooperação em aeronáutica. Finalmente, segue-se uma conclusão ao artigo.
Antibacterial resin composites with sustained chlorhexidine release
2025 - GONCALVES, FLAVIA; SILVA, LARISSA S.T.; ROSCHEL, JULIA N.; SOUZA, GRECA de; CAMPOS, LUIZA de P. M.; VARCA, GUSTAVO H.; PARRA, DUCLERC; PEREZ, MIRKO A.; GORDILHO, ANTONIO C.; BRANDT, WILLIAM C.; BOARO, LETICIA
Background: The addition of chlorhexidine in dental restorative materials is a promising strategy to reduce the recurrence of tooth decay lesions. However, the main challenge is to develop materials with antimicrobial activity in the long term. Objective: This study analyses the effect of filler type and concentration of resin composites supplemented with chlorhexidine loaded in carrier montmorillonite particles (MMT/CHX) regarding their chemical, physical, and short- and long-term antimicrobial proprieties. Materials: Experimental composites were synthesized with 0, 30, or 60% filler in two ratios, 70/30 and 80/20, of barium glass/colloidal silica, respectively, and 5 wt% MMT/CHX. Conversion was measured using near Fourier-transform infrared spectrometry. Sorption and solubility were determined by specimen weight before and after drying and immersing in water. Flexural strength (FS) and elastic modulus (E) were determined by three bending tests using a universal test machine. Chlorhexidine release was monitored for 50 days. Streptococcus mutans UA159 was used in all microbiological assays. Inhibition halo assay was performed for 12 months and, also, biofilm growth for the specimens and colony-forming unit (CFU). Remineralization assay was used on restored teeth using measurements of microhardness Knoop and CFUs. Results: Conversion, sorption, and solubility were not affected by filler type and concentration. FS and E increase with the filler concentration, independent from filler type. Chlorhexidine was significantly released for 15 days for all experimental materials, and the increase in filler concentration decreased its release. Halo inhibition was observed for a longer time (12 months) in materials with 60 wt% filler at 70/30 proportion. Also, 60 wt% filler materials, independent from the filler ratio, reduced the CFU in relation to the control group from 8 to 12 months. In the remineralization assay, besides the absence of differences in hardness among the groups, after biofilm growth, the CFU was also significantly lower in materials with 60 wt% filler. Conclusions: Materials with 60% filler, preferentially with 70% barium glass and 30% silica, and 5% MMT/CHX particles demonstrated long-term antimicrobial activity, reaching 12 months of effectiveness. Also, this formulation was associated with higher mechanical properties and similar conversion, sorption, and solubility compared to the other materials.
The impact of sintering and Mg doping on the ionic conductivity of Sm2Zr2O7 pyrochlores
2025 - BLASCO-ZARZOZO, SILVIA; SANTOS-VEIGA, EMERSON L. dos; CHUNG, U-CHAN; FOURCADE, SEBASTIEN; ELISSALDE, CATHERINE; MAUVY, FABRICE; CORDONCILLO, ELOISA; BELTRAN-MIR, HECTOR
Pyrochlore structures based on Sm2Zr2-xMgxO7-x (x = 0, 0.1, 0.15 and 0.2) were synthesized by hydrothermal method at 180 °C and the resulting powders fired at 1200 °C for 2h. Two sintering methods were employed: Conventional Sintering (CS) with uniaxial pressing and Spark Plasma Sintering (SPS), both at 1350 °C. Resulting pellets had relative densities of ∼70 % (CS) and ∼97 % (SPS), with nano-size grains. Electrochemical Impedance Spectroscopy (EIS) was performed under various atmospheres to assess the impact of sintering on electrical properties. All samples exhibit ionic conductivity, with Mg-doped compositions showing the highest conductivity whatever the sintering process used. SPS samples showed higher conductivity than those sintered by CS, with the x = 0.10 composition (SMZ01) exhibiting the highest conductivity. The overall conductivity was unaffected by atmosphere (air, N2 and H2–N2), indicating good stability and resistance to reduction/oxidation. Notably, SMZ01 sintered by SPS exhibits total conductivity comparable to Yttria-Stabilized Zirconia (YSZ), a standard electrolyte in oxide-ion conducting applications. These Mg-doped ceramics, especially when processed by SPS, offer excellent relative density and conductivity, making them promising candidates for use in Solid Oxide Fuel Cells (SOFCs), Solid Oxide Electrolysis Cells (SOECs), gas sensors, and other clean energy technologies requiring thermal and physical stability.
Deep learning-based segmentation of Jaszczak ACR phantom images for optimized Radium-223 dosimetry
2025 - GRIEBLER, CRISTIAN F.; CORDEIRO, LEANDERSON P.; LIMA, LUIS F.; BOLZAN, VAGNER; DUTRA, VITOR; SA, LIDIA V. de; BONIFACIO, DANIEL A.B.
Precise and personalized absorbed dose estimation in radionuclide therapy is crucial for optimizing treatment efficiency while minimizing harm to healthy tissues. Radium-223 dichloride (Ra-223), an alpha emitter used in treating metastatic castration-resistant prostate cancer, has shown positive results in extending patient survival. However, the current practice of uniform Ra-223 activity administration based solely on patient weight can lead to suboptimal treatment outcomes. Treatment efficacy evaluation involves quantifying activity and absorbed dose through image quality analysis, revealing potential areas for optimization. This work introduces an innovative approach that integrates a deep learning-based model for automated segmentation of the Jaszczak ACR phantom—a tool for image quality analysis in nuclear medicine—with Monte Carlo simulation for dosimetry. The model exhibits efficient segmentation, surpassing 83.7 % in class-wise Dice coefficients, offering a timeefficient alternative to manual segmentation. The study highlights the superior performance of the 89 keV energy window in image quality parameters, emphasizing its role in lesion detection. Additionally, it addresses challenges in achieving accurate quantitative outcomes in nuclear medicine applications, particularly in Ra-223 therapy. These insights contribute to refining dosimetry protocols for Ra-223, enhancing the precision of quantitative outcomes in nuclear medicine. The practical implications extend to improving daily routines for clinical professionals in nuclear medicine applications, showcasing the potential of advanced imaging techniques and computational tools in optimizing Ra-223 therapy.
Biomass-derived porous crystalline calcium-silicates synthesized from chicken eggshell waste using organic amine templates
2025 - GUARNIERI, GUILHERME de P.; SANTISTEBAN, OSCAR A.N.; CANCELLA, ERICK P.; AZEVEDO, EDUARDO R. de; COSENTINO, IVANA C.; MERCURI, LUCILDES P.; SANTORO, MARCELO L.; GODOY, MOACIR F. de; NERY, JOSE G.
Uncontrollable hemorrhage is a major cause of mortality in accidents, trauma, and medical procedures, highlighting the need for effective hemostatic agents. Zeolites and similar materials are promising due to their adsorption properties and ability to concentrate coagulation factors. This study reports the synthesis of calcium- silicates from chicken eggshell waste using TEA.OH, TPA.OH, and TBA.OH as templates. TPA.OH and TBA.OH direct the formation of rhodesite, a fibrous calcium-silicate, while TEA.OH results in quartz. Materials synthesized with TPA.OH and TBA.OH have surface areas of 53.3–100.3m2 g 1 and mesopores ranging from 5.7 to 27.7 nm with pore volumes of 0.018–0.11 cm3 g 1. In vitro coagulation assays (PT, aPTT) revealed that CaZ-3 and CaZ-4 activate factors within the contact system. The recalcification assay shows a significant reduction in clotting time, indicating action via the intrinsic pathway. Thromboelastographic analysis confirms high hemostatic performance: the material prepared with TBA.OH shows a shorter clot formation time (R=1.8 0.5min) and higher maximumclot strength (MA=52.1 1.3mm) than QuikClot, demonstrating its potential as an effective, waste-derived hemostatic agent.
Analysis of the proteome and biochemistry of venom from Tityus Confluens, a scorpion that can be involved in severe envenomation cases in Brazil
2025 - LIMA, LAIS C.; COVALI-PONTES, HENRIQUE R.; LEITE OHANNA G.S.; PERDOMO, RENATA T.; MORAES, LUIZ F.R.N. de; MIGLIOLO, LUDOVICO; MOYSES, MAURICIO N.; SANTOS, NATALIA G.P. dos; PIMENTA, DANIEL C.; RODRIGUES, MARIANA S.; MORAIS-ZANI, KAREN; COELHO, GUILHERME R.; LUCENA, MALSON N.
In Brazil, the annual scorpion sting cases surpass those of other neglected tropical diseases, highlighting a significant public health issue. The severity of scorpion envenomation relates to the venom’s rapid action, complex composition, species identification challenges, and limited antivenom availability. This work aimed to characterize the venom of Tityus confluens through proteomic, enzymatic, and biological analyses while also assessing its reactivity to anti-scorpion antivenom. The electrophoretic analysis revealed seven protein bands, with the most prominent bands at 30, 15, and 10 kDa. The C18-RP-HPLC analysis isolated sixteen primary fractions. The proteomic analysis identified various toxins, including potassium channel toxins, sodium channel toxins, and antimicrobial peptides, as well as other proteins such as hypotensin and metalloproteinases. Antigenic components were identified in the T. confluens venom, which displayed dose-dependent but time-independent amylolytic activity. The ATPase activity significantly increased with 1–10 μg of venom. No cytotoxic effects were observed on carcinoma or non-tumoral cell lines. The T. confluens venom features a complex protein composition rich in toxins that target ion channels and enzymes. It exhibits active enzymatic and antigenic properties, and displays low cytotoxicity. This is the first proteomic research on the composition of T. confluens venom and may provide valuable insights into understanding the clinical manifestations of scorpion stings.
Calibration of 90Sr + 90Y planar sources using thermoluminescent dosimeters, radiochromic film, a PMMA phantom and Monte Carlo simulation
2025 - LITVAC, DANIEL; CALDAS, LINDA V.E.
In some parts of Brazil, 90Sr + 90Y clinical applicators are still in use for dermatological and ophthalmic treatments, even with new technologies worldwide, because they are of lower cost and easier use. Calibration and periodic recalibration of these applicators to verify the absorbed dose rate is essential to ensure accuracy in clinical treatments. This work focused on an alternative calibration method for 90Sr + 90Y sources, utilizing thermoluminescent dosimeters, radiochromic films, and Monte Carlo simulation, following international recommendations. Regarding radiation doses, the thermoluminescent response of μLiF pellets and the response of radiochromic films were evaluated to determine reproducibility, linearity of response, and their dose-response curves. Additionally, radiochromic films were used to determine the dose rate distribution across the areas of the clinical applicators, and the μLiF dosimeters were used as a comparative measure in determining the axial central dose rate of clinical applicators. A PMMA phantom was developed and utilized to perform the calibrations. Monte Carlo simulation was essential for replicating the radioactive properties and correction factors for radiation and deposited doses in two media and at different distances from these sources. This work presents a practical and cost-effective method for calibrating planar 90Sr + 90Y radioactive sources; it was developed to serve locations that lack state-of-the-art technological resources, and was validated for effectiveness and broad applicability. The developed technique allows for long-distance calibration using dosimetric materials, provided they are properly handled and shielded.

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