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Evaluation of the Uncertainty in the Measurement of Nanoparticle Size and Concentration by Single Particle Inductively Coupled Plasma Mass Spectrometry Technique
2025 - GERALDES, ADRIANA N.; HORTELLANI, MARCOS A.; ROSTELATO, MARIA E.C.M.; SARKIS, JORGE E.S.
Single-particle inductively coupled plasma-mass spectrometry (sp-ICP-MS) is a powerful technique that enables the simultaneous measurement of nanoparticle size and the quantification of metal-containing nanoparticles at real concentrations. These measurements are critical for understanding the potential uses of nanoparticles in various fields. However, sp-ICP-MS is not yet considered a mature methodology. Standardization is necessary, particularly in assessing the reliability of size distribution measurements. This study aims to standardize sp-ICP-MS by assessing the reliability of size distribution measurements for polyvinylpyrrolidone-coated silver nanoparticles and quantifying the input quantities contributing to uncertainties. The uncertainties in calibration, repeatability, and trueness were evaluated based on the thresholds defined by International Organization for Standardization (ISO) standards. Calibration uncertainty was found to be 8.1%, while repeatability was 0.04%, both within the stipulated range of less than 10%. The expanded uncertainty was calculated to be 17%, with a 95% coverage probability for the reference material. Limits of detection (LOD) and quantification (LOQ) for dissolved concentration, particles per mL, and size were determined to be 0.37 μg L–1, 97.5 particles mL–1, and 24.6 nm, respectively. These results demonstrate that the reliability and repeatability of sp-ICP-MS meet ISO-defined thresholds, suggesting that with further standardization, sp-ICP-MS could become a reliable methodology for nanoparticle analysis.
Hydrophilic interaction chromatography coupled to high resolution mass spectrometry (HILIC-LC-HRMS)
2025 - VALLA, MONICA V.; LEBRUN, IVO; PUDENZI, MARCOS A.; OLIVEIRA, LAUDICEIA A.; ALMEIDA, HELOISA F.; SANTOS, NATHALIA G.; RODRIGUES, MARIANA S.; SPENCER, PATRICK J.; ROCHA, MARISA M.; PIMENTA, DANIEL C.; COELHO, GUILHERME R.
Although proteins in snake venoms have been extensively studied and characterized, low-mass molecules remain relatively unexplored, mainly due to their low abundance, secondary role in envenomation, and some analytical technique limitations. However, these small molecules can provide new important data related to venom toxins’ molecular structure, functions, and evolutionary relationships. This research aimed to characterize molecules below 10 kDa in the venoms of snakes from the Viperidae families (Bothrops, Agkistrodon, and Bitis) and compare two chromatographic approaches: reverse-phase chromatography (RP), a classic technique, and hydrophilic interaction liquid chromatography (HILIC), an alternative technique, both coupled with high-resolution mass spectrometry (HRMS). The results showed that the separation of the HILIC column provided a more efficient evenly distributed ion profile than RP, contributing to a 25.6% increase in the sequences identified. Homologous sequences for Bradykinin-potentiating peptides (BPPs) and fragments of major venom proteins, possibly cryptids, were found. In addition, BPP 13a, peptides rich in histidine and glycine (pHpG), and spacer sequences were identified in all snakes analyzed, especially with HILIC separation, suggesting that these sequences may be conserved within Viperidae. These findings indicate that the use of the HILIC column, compared to RP, is a promising approach for characterizing peptides in snake venom obtained by the ultrafiltration process. It contributes to the study of these still poorly understood molecules and is also a good option for studying other complex protein/peptide mixtures.
Balancing flexibility and strength of hydroxypropylated starch/cellulose nanofibrils biocomposites
2025 - DA COSTA, FERNANDA A.T.; LOPES, HENRIQUE S.M.; ALVES, LUCAS R.; KOMATSU, DANIEL; MENEZES, APARECIDO J. de; PARRA, DUCLERC F.
This study investigates the thermal-mechanical properties of hydroxypropylated starch (HPS) as a plasticizer for conventional thermoplastic starch (TPS) films, reinforced with cellulose nanofibrils (CNF). A previous study showed that hydroxypropylation of starch led to in-situ poly(propylene oxide) (PPO) formation, inducing gelatinization and yielding TPS with significant plasticizing effect. To address this, blending native cassava starch with HPS and incorporating CNF, as well as hydroxypropylated CNF (mCNF), was explored as a sustainable reinforcement strategy. Films were prepared by casting, and their properties were evaluated using tensile strength tests, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). Results indicate that the incorporation of unmodified CNF significantly increased the tensile strength of HPS/TPS films, demonstrating its effective reinforcing capability. Conversely, adding mCNF led to a reduction in tensile strength, suggesting that the chemical modification of CNF may hinder its reinforcing efficiency due to altered interactions with the starch matrix. FTIR confirmed molecular interactions, while DSC and TG provided insights into thermal transitions and stability. This research emphasizes the potential of combining HPS, native starch, and CNF to create sustainable, high-performance starch-based biocomposites with reduced synthetic plasticizer content, offering a promising approach for diverse applications.
Enhancing jawless VMAT plan quality for hypofractionated left breast cancer with the avoidance structure tool
2025 - CASTELO, J.H.M.; MENEZES, D.C.T.; MENEZES, D.C.T.; ROSA, L.A.R. da; BONIFACIO, D.A.B.
Introduction: The Avoidance Structure (AvS) tool shields a structure by maintaining the multileaf collimator leaves over the structure's projection in the beam's eye view. In this work, we tested the dosimetric impact of using part of the outlines of the heart and lungs as avoidance structure when creating knowledge-based left breast volumetric modulated arc therapy treatment plans. Methods: Dose-volume histogram estimates were calculated using a RapidPlan model for 30 patients who received whole breast radiation therapy in five fractions. Then, two sets of plans were generated for a Halcyon v2 linear accelerator by alternating the use of the AvS tool. Dose metrics for both procedures were compared. Results: Coverage on the target volume remained similar regardless of the use of AvS. The mean absorbed dose received by the heart, as well as the relative volumes receiving 1.5, 3.5 and 7.8 Gy, decreased with effect sizes (ESZ) 0.98, 1.43, and 0.63 respectively. Homolateral lung volumes receiving 1.5 and 3.5 Gy were also lowered using AvS. However, the dose received by 0.03 cc of the contralateral breast increased with an ESZ of 0.52. Conclusions: Except for the contralateral breast, the AvS tool improved DVH metrics for organs at risk without compromising target coverage or worsening hotspots.
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.
Influence of LiF on the Sintering of Si3N4 Ceramics Containing SiO2–CaO–Al2O3
2025 - CORREA, W.T.; SILVA, R.O.; FERREIRA, T.S.; CARVALHO, F.M.S.; GUEDES-SILVA, C.C.
This study investigates the influence of LiF on the sintering behavior of Si3N4 ceramics with SiO2–CaO–Al2O3 at the eutectic composition. Compositions containing 90 wt.% Si3N4 were sintered at 1650–1815 °C for 1 hour. The ceramics were characterized in terms of density, microstructure, and hardness. At 1650 °C, the β/(α+β)-Si3N4 ratio rose from 28.4 % (0 wt.% LiF) to 63.7% (2 wt.% LiF), exceeded 98 % at 1700 °C, and reached 100 % at ≥ 1770 °C. In LiF-free samples, higher sintering temperatures resulted in a higher relative density (95.6 ± 0.4%) and hardness (12.99 ± 0.42 GPa). LiF improved densification and hardness at low content and sintering temperature, yielding 89.4 ± 0.3 % relative density and 9.71± 0.42 GPa hardness (1 wt.% LiF) compared to 84.1 ± 0.5 % and 6.78 ± 0.29 GPa (0 wt.% LiF), both at 1650 °C. At higher temperatures, LiF decreased both properties, likely due to its tendency to evaporate.
Insights and simulation of metascintillator-based brain PET systems to enhance ToF capability
2024 - BONIFACIO, D.A.B.; LATELLA, R.; MURATA, H.M.; BENLLOCH, J.M.; GONZALEZ, A.J.; LECOQ, P.; KONSTANTINOU, G.
The integration of Time-of-Flight (ToF) information into Positron Emission Tomography (PET) image reconstruction enhances both signal-to-noise ratio and the localization of annihilation events. A critical component contributing to the accuracy of ToF-PET is the scintillator. To overcome the time resolution limitations in conventional scintillators, the metascintillator approach has been proposed. The metascintillator is an engineered composition of small units that combines and optimizes various features within a single scintillator heterostructure. In this work, metascintillator-based brain PET systems were simulated using the GATE toolkit and compared with designs based on bulk LYSO or BGO. Sensitivity, noise equivalent count rate (NECR) and scatter fraction were evaluated following NEMA guidelines. To match the peak sensitivity of a system utilizing a 15 mm bulk BGO, the metascintillator-based scanners using BGO/BaF2, BGO/EJ232, LYSO/BaF2 and LYSO/EJ232 must possess thicknesses of 23.2 mm, 22.5 mm, 29.7 mm and 31.1 mm, respectively. With ToF gain, the scanner utilizing a 25 mm thick LYSO-EJ232 metascintillator exhibited the most promising NECR curve, peaking at 1180 cps at 1600 MBq. This work takes a significant step towards harnessing the information gain facilitated by the integration of metascintillator-based detectors in PET imaging.
High red luminescence intensity under sunlight exposure of a PMMA polymer doped with a tetrakis Eu3+ b-diketonate complex containing a benzimidazolium counterion
2025 - ASSUNÇAO, ISRAEL P.; COSTA, ISRAEL F.; BLOIS, LUCCA; FELINTO, MARIA C.F.C.; DEFLON, VICTOR M.; ANDO, ROMULO A.; MALTA, OSCAR L.; BRITO, HERMI F.
New tetrakis Eu3+ and Gd3+ b-diketonate complexes containing benzimidazolium (Bzim) as the counterion were synthesized by the one-pot method. The Bzim[Eu(tta)4]$H2O complex was further incorporated into a poly(methyl methacrylate) matrix (PMMA) at 1, 5, and 10% (w/w), which revealed highly desirable photonic features. The Eu3+ and Gd3+ complexes were characterized by elemental and thermal analyses, in addition to ESI-MS spectrometry, FTIR, and Raman spectroscopy. Single-crystal X-ray diffraction studies of the tetrakis Bzim[Eu(tta)4]$EtOH complex revealed that the Bzim+ counteraction and EtOH molecules exhibited several intermolecular interactions with very short hydrogen bond distances between two [Eu(tta)4]− anion units. The PMMA:(1%) Bzim[Eu(tta)4]-doped material was thermally stable up to 120 °C, which was close to the values found for the Eu3+-complex. Regarding the photoluminescence properties, either the Bzim[Eu(tta)4]$H2O or the doped films showed intense emission arising from the metal ion over a wide range of excitation wavelengths comprising UVA, UVB, and UVC regions. In addition, when the polymer films were exposed to sunlight radiation in an open external environment, the materials revealed a high Eu3+-centered red emission arising from the 5D0 / 7FJ transition. The Bzim[Eu(tta)4]$H2O and Bzim[Eu(tta)4]$EtOH complexes showed high absolute quantum yields (QL Eu) of 56% and 70%, respectively, whereas the doped polymer films displayed only ∼38%. All materials exhibited a highly red monochromatic emission characteristic. We believe that such luminescent systems could be promising photonic materials with a wide excitation range, including UVA, UVB, UVC, and sunlight, acting as efficient light-converting molecular devices (LCMDs).
Luminescence in Ln3+ dipivaloylmethanate complexes
2025 - ARRUDA, JOALDO G.; SILVA, IRAN F.; FAUSTINO, WAGNER M.; COSTA, ISRAEL F.; BRITO, HERMI F.; CARNEIRO NETO, ALBANO N.; NATHER, CHRISTIAN; TERRASCHKE, HUAYNA; FELINTO, MARIA C.F.C.; DEFLON, VICTOR M.; TEOTONIO, ERCULES E.S.
Three novel lanthanide dipivaloylmethanate (dpm) complexes of general formula [Ln(dpm)(NO3)2(tchpo)2], where Ln: Eu3+, Gd3+ and Tb3+, and tchpo: tricyclohexylphosphine oxide neutral ligand have been prepared and characterized by elemental analyses, absorption infrared spectroscopy, thermalgravimetric analyses, diffuse reflectance, and luminescence spectroscopies. Furthermore, the [Tb(dpm)(NO3)2(tchpo)2] complex was structurally characterized by the single crystal X-ray diffraction analysis. This complex exhibited high luminescence intensity in the green region. On the other hand, the analogous Eu3+-complex exhibited very low luminescence intensity due to an efficient luminescent quenching process via ligand-to-metal charge transfer (LMCT) state. Theoretical studies employing Time-Dependent Density Functional Theory (TD-DFT) calculations along with results obtained from the JOYSpectra platform, support this experimental result. Remarkably, despite the high values of non-radiative intramolecular energy transfer from excited ligand states (S1 and T1) to the excited levels of the Ln3+ ions, in the [Eu(dpm)(NO3)2(tchpo)2], the highest S1-LMCT rate (W = 1.2 × 1010 s􀀀 1) emphasizes that the primary luminescence quenching pathway is via depopulation of excited ligand states. Interestingly, the nitrogen atoms from nitrate ions play an essential role in the lanthanide chemical environment, which has been suggested by the analyses of the ligand field parameters charge factors (g) and effective polarizabilities (αʹ) values.
Corrosão localizada do alumínio em meios aerados e em meios com baixo teor oxigênio
2025 - ARAUJO, JOAO V. de S.; GABBARDO, ALINE D.; FERNANDES, STELA M.; COSTA ISOLDA
In this study, the influence of deaeration on the electrochemical behavior of aluminum was studied by polarization techniques. The advantages of deaeration for the evaluation of localized corrosion on aluminum are discussed. The influence of the corrosive environment with low oxygen contents on the electrochemical response of aluminum was evaluated by anodic and cathodic potentiodynamic polarization curves. The polarization tests were carried out in chloride solutions followed by optical and scanning electron microscopy characterization. It was observed that deaeration of the solution significantly influences the electrochemical behavior of aluminum, as predicted by corrosion kinetics theories. For the cathodic curves, a decrease in the limiting current density for the oxygen reduction reaction (ORR) was observed for low oxygen solutions, while the “apparent” initiation of the hydrogen evolution reaction (HER) was shifted to higher potentials. In the anodic curves, a common passive behavior was not observed in aerated conditions, however, at the corrosion potential, localized pitting was observed indicating that the material was already above the breakdown potential (Ebr). In the low oxygen content solution, however, a passive region with a breakdown potential, was observed on the anodic curves.
Experimental Validation of the LabSOCS Detector Efficiency Simulation
2024 - ZAHN, G.S.; GENEZINI, F.A.
The precise knowledge of the detection efficiency for gamma ray spectrometers is often of paramount importance, and its experimental determination can be both timeconsuming and challenging, especially for complex geometries and/or extensive sources. A common solution for that is the use of Monte Carlo simulations, and some companies have developed commercial solutions. In the present work, the accuracy of the efficiency values determined by Mirion Industries’ LabSOCS detection efficiency simulator was assessed by determining the activities of point sources measured under five distinct geometries, and comparing the results to the certified activity values. The results show that, while the software delivers reasonably reliable results, it tends to overestimate the efficiency, and special care may have to be taken with the precision of the geometrical measurements.
Ions and Metals in Polystyrene Samples by X-Ray Fluorescence Technique
2025 - ZANIN, T.; ZAMBONI, C.B.; CARDOZO, B.B.I.; SA FELIZARDO, J.F.; ANJOS, R.M. dos
Plastics are one of the most common and persistent pollutants in ocean waters and beaches worldwide, causing harmful effects on marine biota. The composition of these plastics mainly includes polyethylene (PE) and polystyrene (PS). The marine environment is impacted in various ways and, in extreme cases, diseases can emerge among seafood-consuming inhabitants due to contaminants (such as the toxic additives) in the plastic composition. Specifically, the objective of the present investigation is to analyze ions and metals in PE and PS samples exposed in the Jurujuba region (Baía de Guanabara, Rio de Janeiro, Brazil) for different periods using the Energy Dispersive XRay Fluorescence (EDXRF) analytical technique. This analysis will help identify toxic metals present in these polymer compositions as well as metals adsorbed on the plastic surface, contributing to defining measures to address this issue. Samples (in triplicate) were divided into three groups: I) Standard: sample available commercially; II) Control: sample exposed only to ultra-pure water, in the dark with a controlled temperature of 25 degrees Celsius; III) Exposed samples in Jurujuba (Baía de Guanabara). This study is part of a larger research project “Strengthening capacities in Marine and Coastal Environments using nuclear and isotopic techniques” (IAEA/ARCAL: RLA7025). These results emphases the toxicity of marine pollution and show that PE and PS polymers can act as carriers of pollutants between ecosystems.
Gamma Radiation for Preservation
2024 - NAGAI, M.L.E.; DIAS, D.B.; VASQUEZ, P.
Preserving historical artifacts, such as VHS tapes, in archival collections presents significant challenges, particularly in environments conducive to mold contamination. Inadequate control of temperature and relative humidity can promote mold growth, endangering the structural and informational integrity of these cultural assets. This study explores the application of gamma radiation treatment for the disinfection of mold-contaminated VHS tapes stored in historical archives. Utilizing the Multipurpose Gamma Irradiation Facility at the Institute of Energy and Nuclear Research (IPEN) in São Paulo, Brazil, we investigated the efficacy of gamma radiation in eradicating mold while preserving the tapes' mechanical properties and visual appearance. Despite the long-standing use of gamma ionization for decontamination since the 1960s, this research is novel in its focus on VHS tape preservation. Tensile tests and visual inspections were conducted on control, biodeteriorated, and gamma-irradiated samples. Results showed that gamma irradiation significantly improved tensile strength and strain in mold-contaminated tapes, with no observable changes in their visual appearance. This study contributes to the development of innovative preservation techniques, addressing the unique challenges posed by environmental factors in the storage of historical materials and underscoring the potential of gamma radiation as a dual-function method for disinfection and mechanical reinforcement.
Novel applications of radiation technology on the production of biodegradable packaging for the food industry
2024 - DEL MASTRO, NELIDA L.
The environmental damage human activities are cause is our most present concern. Plastics mainly petroleum-based packaging materials are widely employed in the manufacture of food packaging because of their performance and facility of production. That is leading to serious ecological problems for the environment as synthetic plastics are resistant to biodegradation. Biopolymers can be seeing as a solution to the problems posed by plastics as they easily degrade in the environment. Naturally occurring polymers produced by living organisms show no adverse effects on the environment or human being. For biodegradable food packaging it is required to employ biopolymers with good film formation capability and to employ a proper film formation method. In the present article, the employment of radiation technology in the production of films or coating for food packaging is presented as a novel application.
Study of Organizational Management through Implicit and Explicit Association Measures in Public and Private Management
2025 - MARTINS, M.P.S.; SABUNDJIAN, G.
This study aims to identify the main characteristics of organizations regarding employees' perceptions, paradigms and prejudices regarding organizational management. Although the Institute of Energy and Nuclear Research (IPEN-SP) and the University of Rio Verde (UniRV - GO) were chosen to conduct this research, this study will present the results of the application of a questionnaire (explicit test) only to a group of IPEN employees. The topics addressed in this research were: bureaucracy, organizational participation, and innovation, among others. Due to the cultural diversity in Brazil and consequently in companies, there are several models of organizational management. However, for the scope of this study, two models are considered: participatory management, focused on innovation, and autocratic management, in which the manager makes decisions unilaterally, without the participation or consultation of employees. These two management models were chosen to stimulate the behavioral profile of employees, that is, it is a way of understanding and identifying the employee's reaction or positioning in a specific situation. The methodology used as a data collection instrument involves the Implicit Association Test (IAT) (unconscious) and explicit (conscious) which is done through a questionnaire. This paper will only present the explicit association test (questionnaire) that was applied to IPEN employees. To apply the implicit association tests, the FreeIAT software will be used, although its application will be done in the next phase of this work as described in this article. The first results of the explicit association test (questionnaire) demonstrate, through the calculation of Cronbach's alpha, its high consistency and reliability.
Radiation influence on antioxidant capacity, bioactive compounds and extractability of coffee processing residues
2025 - BARROS, J.P.A.A.; RONDAN-FLORES, L.M.; NEGRAO, B.G.; SALIBA, A.S.M.C.; ALENCAR, S.M.; VIEIRA, D.P.; VILLAVICENCIO, A.L.C.H.
During the agro-industrial process, the complete reuse of waste is an important part of the process's sustainability. However, in most cases, these materials are inadequately discarded, bringing environmental, economic, and social implications. In this context, residue reuse represents an opportunity to develop by-products, in addition to adding value to the raw material. However, conventional treatment processes end up negatively altering the quantity and expressiveness of compounds and nutrients present in this residue. Therefore, ionizing radiation has stood out as a promising technique among the current resources available for residue reuse and microbial load reduction. Thus, the objective of this work is to apply ionizing radiation to coffee processing residues, such as husk and straw, with the aim of preserving and improving the compounds and antioxidant activity. For this purpose, doses of 5 kGy were used on husk and straw residue. The samples were subjected to extraction through physical and chemical processes to obtain an extract from the residue. The extracts were analyzed to identify total phenolic content (TPC), antioxidant activity (ABTS, FRAP, and ORAC), extraction efficiency (EE), and cytotoxicity assays. An improvement in TPC of 26.0% for husk and 19.5% for straw was observed. For antioxidant capacity, an improvement of 14.1%, 16.1%, and 33.3% for husk was observed in ABTS, FRAP, and ORAC analyses, respectively. The 5 kGy dose provided an increase in compound extractability of 26.7% (straw) and 191.9% (husk). In cytotoxicity tests, no significant differences were observed between the irradiated residue and the control. However, an effect related to extract concentration was observed. The irradiation process proved to be a promising technique for agro-industrial residue management. This technique, in addition to promoting already known microbiological benefits, also improved the quantity of compounds, antioxidant activity, and compound extractability. Thus, the present proposal highlights the application of nuclear energy as a viable solution and technological innovation for the reuse of agro-industrial residue.
Electron beam application to fluoxetine and surfactant mixture degradation, with persulfate, and toxicity approach
2026 - TOMINAGA, FLAVIO K.; NUNES, ROBERTA F.; GARCIA, VANESSA S.G.; TEIXEIRA, ANTONIO C.S.C.; BORRELY, SUELI I.
Electron beam irradiation (EBI) is an essential tool for removing organic pollutants from water and wastewater. Depending on the type of effluent being treated, this process can be combined with persulfate to enhance removal efficiency. The simultaneous effects of persulfate (PS) initial concentration and absorbed dose on the degradation of the antidepressant fluoxetine were investigated: a binary mixture (fluoxetine and surfactant sodium dodecyl benzene sulfonate) was treated, following a Doehlert experimental design. Toxicity tests were also conducted using Daphnia similis . Additionally, the surfactant aqueous solution was treated by an electron beam accelerator. The results showed that 90.1 ± 1.1 % of fluoxetine in the mixture was removed at a dose of 5.0 kGy. The combination of irradiation with persulfate (PS) significantly improved fluoxetine removal compared to EBI, consistently achieving over 90 % removal. However, higher concentrations of persulfate (2.5 mmol L−1) did not increase fluoxetine removal. Toxicity tests were performed on samples treated under the optimized conditions ([PS]0 = 1.1 mmol L−1; absorbed dose - 4.5 kGy) and revealed an increase in Daphnia similis toxicity, suggesting the formation of toxic byproducts. Concerning the data obtained for the aqueous solution of irradiated surfactant, more than 90 % degradation was achieved in the evaluated doses (2.5 and 5.0 kGy), resulting in a 70 % reduction in toxicity at 5.0 kGy.
Beta-lactam antibiotics under light
2026 - SALANI, RENATA; DEANA, ALESSANDRO M.; NUNEZ, SILVIA C.; FROCHOT, CELINE; SILVA, DANIELA de F.T.; PAVANI, CHRISTIANE
Antibiotics (ATBs) remain a cornerstone in the treatment of bacterial infections, yet clinical practice increasingly incorporates photonic therapies such as photobiomodulation (PBM) and photodynamic therapy (PDT). These modalities, widely used in infectious and inflammatory conditions, are frequently administered concomitantly with ATBs. However, the potential photochemical interactions between β-lactam ATBs and light-based therapies remain poorly understood, raising questions about efficacy and safety in combined treatment settings. In this study, we characterized the optical and photochemical properties of representative β-lactam ATBs, including penicillins (amoxicillin, oxacillin), cephalosporins (cephalothin, cefazolin, ceftazidime, ceftriaxone, cefuroxime), and a carbapenem (meropenem). Using diffuse transmittance and reflectance spectroscopy, we calculated absorption and scattering coefficients via the Kubelka–Munk function. Reactive oxygen species (ROS) generation was assessed under direct blue light (460 nm) illumination and red light exposure in the presence of methylene blue (MB), a clinically employed photosensitizer. Cephalosporins demonstrated significant ROS generation under blue light, whereas penicillins and meropenem did not. In PDT-like conditions, meropenem enhanced MB-mediated ROS production and promoted MB photobleaching, suggesting potentiation of PDT effects. In contrast, penicillins suppressed MB-driven ROS generation, potentially limiting PDT efficacy. Cephalosporins showed heterogeneous effects, either enhancing, reducing, or leaving MB-induced ROS unchanged. These findings indicate that β-lactam ATBs exert distinct photobiological behaviors with potential clinical consequences. Cephalosporins may act as intrinsic photosensitizers, meropenem may potentiate PDT, and penicillins may attenuate phototherapy efficacy. Recognizing such interactions is critical to optimizing combined ATB–phototherapy regimens and avoiding unintended antagonism or toxicity in clinical practice.
Optimizing scaffold properties for nerve regeneration
2026 - LOURENÇO, LARISSA R.; BORGES, ROGER; MATHOR, MONICA B.; ALBERTO-SILVA, CARLOS; MARCHI, JULIANA
Peripheral nerve injuries remain a challenge for regenerative medicine and, when not properly healed, yield significant consequences for the patient, such as functional loss and neuropathic pain. Despite the intrinsic repair capacity of these structures, the process is limited to mild injuries and may not result in functional recovery. The gold standard in this field is the use of autologous grafts; however, this method has several disadvantages, including donor tissue morbidity and a low functional recovery rate. In this study, we developed 3D printed chitosan scaffolds with varying bioactive glass concentrations for application in peripheral nerve regeneration. Adding bioactive glass allowed better control over liquid absorption and degradation time. Moreover, lower concentrations of the ceramic particles improved maximum elongation and showed suitable mechanical properties for nerve repair. Bioactive glass addition significantly improved scaffold-cell interactions, increasing adhesion and proliferation of nerve-like cells, properties that can enhance the regenerative process. Thus, chitosan scaffolds with bioactive glass show promise for the proposed application, with a notable concentration of 1 %, which exhibited suitable physical and chemical characteristics for nerve repair, as well as improvements in biological properties.
Processing, microstructural, and mechanical characterization of extruded 6013 aluminum alloy
2025 - TORRES, RENATA Q.; ALMEIDA, GISELE F.C.; HATTORI, CAROLINA S.; SILVA FILHO, LUIZ C. da
The 6013-aluminum alloy is used in automotive applications due to its higher levels of mechanical strength. This work aimed to characterize the microstructural and mechanical properties of this alloy obtained in various stages of industrial processing. The alloy was subjected to homogenization, extrusion and solubilization, tempering, and artificial aging processes. The microstructure was characterized by optical (OM), scanning electron (SEM), transmission electron microscopy (TEM), and X-ray diffraction technique (XRD). In the as-cast condition, the present phases in the 6013-alloy were almost completely precipitated at the α phase grain boundaries. Homogenization and solubilization during the extrusion process strongly reduced the amount of these precipitates. The α-phase morphology showed a heterogeneous distribution along the thickness of the extruded profile, with recrystallized grains close to the surface and many work-hardened grains inside. The aging heat treatment significantly increased the extruded profile mechanical strength. In the analysis of the present phases, it was possible to identify, in addition to the α-Al phase, the compounds precipitated in greater quantity, such as Mg2 Si, β-AlFeSi, and α-AlFeSi.

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