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URI Permanente para esta coleçãohttps://repositorio.ipen.br/handle/123456789/50015

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Sedimentation and growth of volcanic aerosols within the Hunga plume
2025 - SOUZA, GIOVANNI; VERNIER, JEAN PAUL; QUINTÃO, DEMILSON; BIAZON, BRUNO; LOPES, FABIO; RICARDO, JHONATHA; PANDIT, AMIT K.; CHANDRA, RUBEL das; LIU, HONGYU; KNEPP, TRAVIS N. N.; VERNIER, HAZEL; LANDULFO, EDUARDO
The Hunga eruption was an unprecedented event which influenced stratospheric aerosols. This study analyzes the unique dynamics of aerosol plumes using balloon measurements from the Brazil Volcano campaign in Bauru (22.36° S, 49.03 °W) and the Stratospheric Aerosol and Gas Experiment III/ISS along with theoretical calculations. They revealed consistent trends in particle sedimentation and spreading. Temporal analysis showed that smaller particles (<225 nm) experienced slower sedimentation rates, with a larger influence by the Brewer-Dobson circulation. Larger particles (>400 nm) exhibited faster sedimentation, descending approximately 3 km by the end of 2022. The descent of the plume into the Upper Troposphere and Lower Stratosphere (UTLS) by February-March 2023 is accompanied by an increase of effective radius from 400 nm to 450 nm due to hygroscopic growth from moist convection. These unique observations suggest that Hunga could have impacted cirrus cloud formation by re-entering the UTLS.
Recognizing microplastic deposits on sandy beaches by altimetric positioning, Μ-Raman spectroscopy, and multivariate statistical models
2024 - FERREIRA, ANDERSON S.; WETTER, NIKLAUS U.; RIBEIRO, MARIA C. H.; ESTEVES, LUCIANA S.; DIAS, ANTÓNIO G.; GROHMANN, CARLOS H.; KUZNETSOVA, MARIA; OLIVEIRA, REGINA C. de; FREITAS, ANDERSON Z. de; SIEGLE, EDUARDO
This study examines microplastic (MP) pollution along São Paulo State's coast, southeastern Brazil, using geodetic surveys, beach morphometric analyses, sediment collection, µ-RAMAN spectrometry, and multivariate statistical models. The coastline was divided into six compartments (C1 to C6) for sampling. Higher MP concentrations were found in C3 and C2, influenced by industrial and port activities. MP types, including pellets, fragments, and fibers, showed distinct distribution patterns based on their sources and properties. Fragments and foams were most common, constituting 42% and 35% of the 1,026 MPs found. Statistical tests linked MP types to beach morphometric characteristics, with higher elevations correlating with higher MP concentrations, especially pellets and foams. Beaches with intermediate profiles and those facing south accumulated more MPs. The study highlights the complexity of MP dynamics in coastal environments and the need for developing specific monitoring and environmental remediation strategies, supporting Sustainable Development Goal 14 (Life Below Water).
Development of a fast simulator for GEM-based neutron detectors
2022 - SANTOS, RENAN F. dos; MUNHOZ, MARCELO G.; MORALLES, MAURICIO; SERRA FILHO, LUCAS de A.; BREGANT, MARCO; SOUZA, FERNANDO A. de
Gas Electron Multiplier (GEM)-based detectors using a layer of 10B as a neutron converter is becoming popular for thermal neutron detection. A common strategy to simulate this kind of detector is based on two frameworks: Geant4 and Garfield++. The first one provides the simulation of the nuclear interaction between neutrons and the 10B layer, while the second allows the simulation of the interaction of the reaction products with the detector gas leading to the ionization and excitation of the gas molecules. Given the high ionizing power of these nuclear reaction products, a full simulation is very time consuming and must be optimized to become viable. In this work, we present a strategy to develop a fast simulator based on these two frameworks that will allow us to generate enough data for a proper evaluation of the expected performance and optimization of this kind of detector. We will show the first results obtained with this tool concentrating on its validation and performance.
Increase in the platinum group elements content in road dust from São Paulo city, Brazil, due to exhaust emissions from vehicle catalytic converter, over a 10-year period
2023 - HORTELLANI, MARCOS; SARKIS, JORGE J.E.S.
Platinum Group Elements (PGEs) are widely used as catalysts in vehicle emission reduction, and road dust is a primary receptor for PGE releases. However, the determination of PGEs in these samples by ICP-MS is affected by matrix interferences, and measurement and sampling uncertainties are often overlooked. This study presents the first PGEs measurements in road dust samples from São Paulo city avenues, including matrix separation and estimation of measurement uncertainty includes analytical and sampling uncertainties. Measurement uncertainties for PGEs ranged from 12.3% to 19.5%, and analytical uncertainty ranged from 2.25% to 5.64%. PGEs concentrations: Pt (2.6 - 227 ng g-1), Pd (16.3 - 1875 ng g-1), Rh (2.02 - 257 ng g-1). Three methodologies were applied to evaluate the PGEs and other metals contamination in 54 road dust samples (< 100 µm fraction) collected in 2008, 2016 and 2018 at 18 sites with high (17 sites) and low (1 site) volumes of traffic. Metal pollution index (MPI), enrichment factor (EF) and statistical analyses. These evaluations suggested that PGEs and Mo contamination were originated from automobile exhaust emissions. Cu and Zn contamination seemed to have been caused by tires and brakes vehicular sources (non-exhaust emissions), but Ni and Pb contamination seemed from non-vehicular sources. Only rare earth elements are mostly associated with crustal source. The changes in PGE ratios stemmed from decreased Pt and increased Pd concentrations. A considerable portion of these metals in road dust is bioaccessible and poses health risks to the population near high-traffic density avenues, through ingestion, dermal contact, and inhalation pathways.
Effect of nutritional stress and serum starvation on the optical absorbance of normal and malignant epithelial cell lines
2024 - NOBILE, JULIANA S.; HEGUEDUSCH, DANIELE; CARVALHO, GIOVANNA L.; SILVA, DANIELA; CECATTO, REBECA B.; LABAT, RODRIGO; NUNES, FABIO D.; RODRIGUES, MARIA F. S. D.
Photobiomodulation has the potential to modulate cellular responses in various pathological conditions by affecting different signaling pathways. This study aimed to investigate the optical absorbance spectra of normal, dysplastic, and malignant epithelial cell lines under normal and nutritional stress conditions. HaCAT (keratinocyte), DOK (oral dysplastic), and oral squamous cell carcinoma (OSCC) cell lines (CA1, Luc4, SCC9) were evaluated regarding their optical absorbance after culture with 0-10% fetal bovine serum. Absorbance measurements indicated that HaCAT under serum starvation exhibited higher absorbance at blue (430nm) and near-infrared (906nm) wavelengths. DOK showed absorption at 440 nm and 945 nm. OSCC cells showed absorption peaks at blue (400-428nm) and near-infrared. These findings highlight the importance of tailoring PBM parameters to individual needs to achieve optimal absorption and effectiveness. Moreover, the higher absorption peaks in the blue region support further studies to elucidate the potential use of blue light in oral dysplastic lesions and OSCC.
Development of hydrophobic graphenoid layer on portland cement for non-thermal plasma method
2024 - SOUZA, RODRIGO F. B. de; PEREIRA FILHO, NIVALDO G.; FERREIRA, JOÃO C.; ANDRADE, DELVONEI A. de; SOARES, EDSON P.; OLIVEIRA NETO, ALMIR
This study focuses on the development of hydrophobic layer on Portland cement using graphenoid materials to enhance impermeability and hydrophobicity. X-ray diffraction analysis revealed that characteristic peaks associated with concrete remained intact, indicating the presence of phases such as ettringite, calcium hydroxide, calcite, and more. Remarkably, the application of graphenoid material produced by non-thermal plasma resulted in the formation of carbonaceous structures with minimal impact on the overall cement structure. Raman spectroscopy provided detailed insights into the composition, highlighting the presence of specific and indicating boundary defects. Moreover, contact angle measurements confirmed a substantial increase in hydrophobicity for the graphene-coated cement, with an average angle of 117° +/- 4.72° demonstrated graphenoid material layers deposited over structural defects, effectively waterproofing and enhancing local hydrophobicity.
Evaluation of low-kV energy X-ray radiation effect on breast cancer cells incubated with gold nanoparticles capped with aminolevulinic acid, methyl aminolevulinate, and gamma-aminobutyric acid
2023 - LOPES, ISABELA S.; SANTOS, NOEMY R.; SILVA, GIOVANA D. da; VIEIRA, DANIEL P.; COURROL, LILIA C.
Gold nanoparticles (AuNPs) have unique properties, including size-dependent optical and electronic characteristics, biocompatibility, and ease of functionalization, making them attractive for various diagnostic and therapeutic applications. The goal of this work was to verify the potential application of gold nanoparticles capped with aminolevulinic acid (ALA), methyl aminolevulinate (MALA), and gamma-aminobutyric acid (GABA) in low-energy X-ray diagnostics and therapy of breast cancer. ALA and MALA induce the accumulation of protoporphyrin IX (PpIX) in cancer cells. PpIX, in turn, can be excited by Cherenkov radiation, producing reactive oxygen species after energy or electron transfer from the triplet excited state of PpIX to molecular oxygen, which induces cell death by apoptosis or necrosis. The results indicated that ALA and MALA nanoparticles promoted reduced cell viability by approximately 20% with X-ray irradiation at an energy level of 35 kV for 5 minutes. Breast cancer cells possess GABA receptors, allowing for targeted effects by GABANPs, which can enhance contrast and improve diagnostic potential. GABAAuNPs also demonstrated decreased cell viability in ~10% following X-ray irradiation, making them a promising material for both breast cancer diagnosis and treatment.
A new 124Xe irradiation system for 123I production
2023 - COSTA, OSVALDO L. da; BARCELLOS, HENRIQUE; MATSUDA, HYLTON; SUMIYA, LUIZ C. do A.; JUNQUEIRA, FERNANDO de C.; MATSUDA, MARGARETH M. N.; LAPOLLI, ANDRÉ L.
Since 2001, the Nuclear and Energy Research Institute IPEN-CNEN has produced iodine123, weekly, using a manual irradiation system, fully developed in IPEN. Ultrapure 123I has been produced and distributed to hospitals and clinics, where several diagnostic imaging procedures are done for thyroid, brain and cardiovascular functions. Due to the short half-life and emission of low-energy photons, this radioisotope becomes suitable for diagnosis in children. In the present work, will be presented all the technical and constructive aspects of a new fully automated irradiation system, dedicated to 123I routine production, employing enriched xenon-124 gas as the target material. This new system consists of a target, a water and a helium cooling system, a cryogenic system, an electric power system, and a control and process monitoring unit, composed of a supervisory software, connected to a programmable logic controller via personal computer. In this new concept, there is no need for human interference during radioisotope production, reducing the possibility of eventual failures or incidents involving radioactive material. In this way, with this new system, a specific yield, of 2.70 mCi/µAh per irradiation was achieved, in validation essays of the system and, after three years of routine production of iodine-123, the system showed reliability and resilience.
Blue nests: the use of plastics in the nests of the crested oropendola (Psarocolius decumanus) on the Brazilian Amazon coast
2024 - LOPES, ADRIELLE C.; KUZNETSOVA, MARIA; FERREIRA, ANDERSON S.; WETTER, NIKLAUS U.; GIARRIZZO, TOMMASO; MARTINELLI FILHO, JOSÉ E.
Birds have been impacted by plastic pollution via entanglement, accidental ingestion, and exposure to chemical contaminants. However, plastics were also observed as a nesting material for several species. For the first time, we describe the occurrence and composition of plastics in the nests of the crested oropendola (Psarocolius decumanus) in three sites on the Amazon coast. Plastics were present in 67% of abandoned, fallen nests. At the mangrove site, all nests contained plastics, while at the grassy clearing and the fishermen's village, plastics were present at 35.3 and 90% of the nests, respectively. Blue fibers and ropes were the main plastics observed, probably derived from discarded fishing gear. Of 79 analyzed fibers, 97.5% were composed of Polyethylene, and 83.5% contained Cobalt Phthalocyanine as an additive. Our results showed a widespread use of plastics by P. decumanus, which may increase the exposure of juveniles to potential contaminants.
Citizen science data on urban forageable plants
2024 - SOARES, FILIPI M.; PIRES, LUÍS F.; GARCIA, MARIA C.; CORADIN, LIDIO; GHILARDI-LOPES, NATALIA P.; SILVA, RUBENS R.; CARVALHO, ALINE M. de; GAVAI, ANAND; BOUZEMBRAK, YAMINE; MACULAN, BENILDES C.M. dos S.; KOFFLER, SHEINA; MONTEDO, UIARA B.; DRUCKER, DEBORA P.; SANTIAGO, RAQUEL; CARVALHO, MARIA C.P. de; LIMA, ANA C. da S.; GABRIEL, HILLARY D.E.; FRANÇA, STEPHANIE G.M. de; ALMEIDA, KAROLINE R. de; SANTOS, BÁRBARA J. dos; SARAIVA, ANTONIO M.
This paper presents two key data sets derived from the Pomar Urbano project. The first data set is a comprehensive catalog of edible fruit-bearing plant species, native or introduced in Brazil. The second data set, sourced from the iNaturalist platform, tracks the distribution and monitoring of these plants within urban landscapes across Brazil. The study encompasses data from all 27 Brazilian state capitals, focusing on the ten cities that contributed the most observations as of August 2023. The research emphasizes the significance of citizen science in urban biodiversity monitoring and its potential to contribute to various fields, including food and nutrition, creative industry, study of plant phenology, and machine learning applications. We expect the data sets to serve as a resource for further studies in urban foraging, food security, cultural ecosystem services, and environmental sustainability.
Validation of chromatographic analytical methods, TLC and HPLC, to determine the radiochemical purity on the radiopharmaceutical [177Lu]-PSMA I&T
2024 - SANTOS, JOEL M.; BALIEIRO, LUIZA M.; SANTOS, RODRIGO S.; MATSUDA, MARGARETH M.N.; ARAUJO, ELAINE B.
The Energy and Nuclear Research Institute (IPEN) is studying the production of the radiopharmaceutical [177Lu]-PSMA I&T, in accordance with the good manufacturing practices recommended by ANVISA, to be used in the therapy of prostate cancer. This work aims to validate chromatographic methods, TLC and HPLC, to determine the radiochemical purity of the product. The entire validation process of this work was based on ANVISA's RDC 166, 2017 and the Guide 10, version 1, 2017, guided the statistical treatments adopted. The selectivity study found that the presence of impurities or excess excipients did not interfere with product quantification. The proposed methods were linear with linear correlation coefficients (r) above 0.99. The precision and repeatability presented relative standard deviation values lower than specified (RSD < 5 %). The small controlled variations in the method suggested for the robustness test also did not affect the radiochemical purity of the product. In view of the results and in accordance with the criteria established by the National Health Surveillance Agency (ANVISA), the two chromatographic methods were validated in accordance with RDC 166, 2017, proving to be selective, precise, linear and robust. The validation of TLC and HPLC methods enables their application in the batch release routine of the new radiopharmaceutical at Radiopharmacy Center of IPEN
Distribution and characteristics of microplastic deposits on sandy beaches
2024 - FERREIRA, ANDERSON S.; WETTER, NIKLAUS U.; RIBEIRO, MARIA C.H.; ESTEVES, LUCIANA S.; DIAS, ANTONIO G.; GROHMANN, CARLOS H.; KUZNETSOVA, MARIA; OLIVEIRA, REGINA C.; SIEGLE, EDUARDO
This study conducts a comprehensive investigation of microplastic (MP) pollution along the São Paulo State coastline (Brazil). The primary sources of MPs are identified as inadequate plastic waste management and containment system failures in port and industrial areas. These pollutants not only compromise the natural beauty of the beaches but also negatively impact marine life by altering the physical and chemical characteristics of the beaches and impacting dependent ecosystems. The research utilized a five-step methodology comprising a geodetic survey, analysis of beach morphometric parameters, collection of beach sediments, µ-RAMAN spectrometry for polymer identification, and the application of multivariate statistical models. For MP sample collection, the coastline was divided into six segments (C1 to C6). The results indicated higher MP concentrations in C3 and C2, suggesting the influence of industrial and port activities. Various MP types, such as pellets, fragments, and fibers, exhibited distinct distribution patterns, likely due to their different sources, intrinsic properties like shape and density, and emission and deposition processes. The analysis for the entire São Paulo coast revealed that beaches with characteristics (intermediate profile and facing the southern quadrant) tend to accumulate more MPs. The predominance of polymers such as polyethylene and polypropylene reflect the influence of industrial products on marine pollution. This study highlights the complexity of MP dynamics in the coastal environment and underscores the importance of considering the physical characteristics of the beaches, the diversity of MP types, and local human activities. Identifying areas more prone to the accumulation of this emerging pollutant is critical for developing targeted environmental monitoring and remediation strategies, which align with the peculiarities of each coastal region and contribute to the Sustainable Development Goals related to ocean health (SDG – 14).
Nuclear Medicine in Brazilian Health System
2023 - POZZO, LORENA; OLIVEIRA, MERCIA L.; MENEZES, MARIO O.; TOSCAS, FOTINI S.
Nuclear Medicine is crucial for the care of patients with diseases, especially oncological and cardiovascular ones. However, access to it is unequal due to the lack of equipment and producing and supplying units of inputs. Current legislation does not adequately address these aspects, and the dominance of foreign capital is a concern, as it can lead to the scrapping of the current system. National production of radiopharmaceuticals has suffered numerous setbacks, such as budget cuts, indiscriminate market opening, and delays in completing the Brazilian Multipurpose Reactor project. Public data from 2015 to 2021 were analyzed to evaluate access to Nuclear Medicine by the Brazilian Unified Health System (SUS), including the number of facilities, procedures, tariffs, and trade balance. Although Brazil has many Nuclear Medicine facilities, its geographic distribution is extremely uneven. Factors such as equipment acquisition and maintenance costs and lack of qualified personnel are real obstacles to the expansion of Nuclear Medicine in Brazil. The country is financially dependent on foreign capital for this area, which limits its expansion according to SUS guidelines. Social and economic policies are necessary to minimize SUS technological vulnerabilities, promote system sustainability, and ensure universal and equitable access to specialized healthcare services.
Using Brazilian health surveys 2013 and 2019 for a nationwide diabetes risk assessment
2023 - SILVA, MARCELO M. da; MENEZES, MARIO O. de
Brazil had, in 2021, almost 15.7 million people with diabetes (type 1 and 2). In this work, using the Pesquisa Nacional de Saúde (PNS) 2013 and 2019, the diabetes risk for the entire population covered by those surveys, with 18 years and older, was assessed applying the American Diabetes Association Risk Test. Only one question from that test, regarding relatives with diabetes, could not be answered from the PNS questionnaires. After applying the test to both PNS 2013 and 2019, 15.9% and 19.0% of the population with 18+ years was found to be at risk of developing diabetes, representing about 23 and 28 million people, respectively. Those with 65+ years were found to be more at risk, increasing from 42.3% in 2013 to 46.0% in 2019. A good result came from those with BMI > 30, whose percentage at risk dropped from 47.9% in 2013 to 42.5% in 2019. Brazilian states with the biggest risk increase were Tocantins, Mato Grosso do Sul, Piauí and Bahia, all with more than 4pp, while ten states had increases bigger than 3pp. The results obtained in this work corroborate recent findings in diabetes prevalence studies and also reinforce the great importance of such nationwide health survey, as it represent an invaluable resource to public health policies.
Experimental design of size variation in albumin nanoparticles synthesized by electron beam
2023 - FERREIRA, ARYEL H.; LIMA, CAROLINE S.A.; CRUZ, CASSIA P. da; FREITAS, LUCAS F.; FURLAN, GUSTAVO N.; LIMA, ROBSON C. de; SARRIES, GABRIEL A.; LUGAO, ADEMAR B.
Protein-based nanoparticles are of great interest for theragnostic applications such as cancer treatment and nuclear medicine. Beyond that, plasma proteins are particularly attractive as they can circumvent the rapid clearance of synthetic particles. Human serum albumin (HSA) is already used for diagnosis purposes, such as lymphoscintigraphy and sentinel lymph node detection, and in cancer treatment to deliver therapeutic agents in which the nanoparticulated form is employed. Among the techniques adopted for protein nanoparticle synthesis, ionizing radiation can provide good size control and preserve protein three-dimensional structure. Depending on the reaction precursor, pH, protein concentration, presence of stabilizer, and irradiation dose, it is possible to tailor nanoparticles size and shape. Therefore, this work aimed to find a correlation between albumin nanoparticle size and reaction parameters such as protein concentrations, buffer solution, and e-beam irradiation dose. Different syntheses were performed with varying BSA concentrations, two different buffers, and dose radiation. The nanoparticles were then evaluated by Dynamic Light Scattering, and the data regarding sizes were statistically analyzed by SAS studio, SAS JMP, and WEKA software to obtain any correlation among the synthesis variables. It was mainly possible to observe that smaller protein concentrations always lead to smaller particles and that using Tris-HCl buffer as media provided a more proportional growth of particles according to concentration and dose irradiation increases. Thus, these observations indicate that Tris buffer was more appropriate for BSA nanoparticle synthesis as the increase of albumin concentration and radiation dose led to more homogeneous size control.
Radiation effects on eu-complex-doped pmma and nanosilver compounds after exposure to Irradiation
2025 - PARRA, DUCLERC F.; LIMA, VINICIUS; ZAHARESCU, TRAIAN; LUGAO, ADEMAR B.
The evaluation of the stability of PMMA/europium (III) complexes with various ligands: 3-thenoyltrifluoroacetonate (TTA), triphenyl phosphine oxide (TTPO) and water assisted by - irradiation is the goal of this study. The nonisothermal chemiluminescence (CL) measurements reveal the dependence of this stability on the filler concentration. The values of onset oxidation temperature (OOT) obtained from CL spectra are the basic characterization criteria, which are correlated with the sample composition, the irradiation dose and the environment containing the radiolysis fragments. The systems investigated were the luminescent systems PMMA:Ag:Eu(tta)3 and PMMA:Ag:Eu(tta)3(tppo)2 obtained from the PMMA doped with europium (III) complexes. The inclusion of silver nanoparticles into the molecular structures of complexes diminishes the rate of oxidation through the mechanism of RO. scavenging by action of the nanosilver. The Europium ion emitter, surrounded by the ligand had Eu(III) luminescence enhancement, rationalized by the local field enhancement produced by the surface plasmons in silver NPs. The results indicate that these materials have optical marker properties for integrating special devices subjected to high energy transfers.
Methane to methanol conversion using PEM fuel cell and PdAu/ATO nanomaterials
2023 - MAIA, VITORIA A.; NANDENHA, JULIO; GOLÇALVES, MARLON H.; SOUZA, RODRIGO F.B. de; OLIVEIRA NETO, ALMIR
This study investigates the use of Au-doped Pd anodic electrocatalysts on ATO support for the conversion of methane to methanol. The study involves cyclic voltammetry, in-situ Raman spectra, polarization curves, and FTIR analysis to determine the optimal composition of gold and palladium for enhancing the conversion process. The results demonstrate the potential for utilizing methane as a feedstock for producing sustainable energy sources. Pd75Au25/ATO electrode exhibited the highest OCP value, and Pd50Au50/ATO had the highest methanol production value at a potential of 0.05 V. Therefore, it can be concluded that an optimal composition of gold and palladium exists to enhance the conversion of methane to methanol. The findings contribute to the development of efficient and sustainable energy sources, highlighting the importance of exploring alternative ways to produce methanol.
Physical chemical, immunological and biological characterization of arapaima 2 gigas follicle-stimulating hormone (ag-FSH) synthesized in HEK293 cells
2024 - LIMA, ELIANA R.; SEVILHANO, THAIS; CARAMORI, THAIS; OLIVEIRA, JOAO E.; SUZUKI, MIRIAM F.; TORATI, LUCAS S.; BARTOLINI, PAOLO; PERONI, CIBELE N.
The cDNA sequences of the common gonadotrophic hormone α‐subunit (ag‐GTHα) and of the specific follicle‐stimulating hormone β‐subunit (ag‐FSHβ) of the giant Amazonian fish Arapaima gigas, have been previously isolated by our research group. A synthesis of ag‐FSH in HEK293 cells and its purification and preliminary characterization were also carried out. In the present work, ag‐FSH was obtained and purified from the same host cells and an extensive physical chemical characterization was performed via RP‐HPLC, HPSEC and MALDI‐TOF‐MS. Ag‐FSH, when compared to human FSH (hFSH), showed a higher hydrophobicity by RP‐HPLC and a higher molecular mass (MM) via HPSEC. The same higher MM was also confirmed via MALDI‐TOF‐MS: 35,353 Da for ag‐FSH against 31,969 Da for hFSH. Its immunological activity was also confirmed via an hFSH ELISA, in comparison with the highly purified pituitary preparation of hFSH‐AFP7298A, from the National Hormone and Pituitary Program (NHPP‐USA). Finally, an in‐vitro bioassay, based on the stimulated release of 11‐ketotestosterone (11‐KT) from immature A. gigas testis, quantified its biological activity in comparison with human chorionic gonadotropin (hCG) and with the WHO International Standard of recombinant hFSH (NIBSC‐08/282) This suggests that injections of ag‐FSH in A. gigas and ag‐FSH cDNA Gene Therapy applications should improve the reproductive functions of this threatened species.
Enhanced carbon monoxide tolerance of platinum nanoparticles synthesized through the flash joule heating method
2023 - SOUZA, RODRIGO F.B.; NANDENHA, JULIO; OTUBO, LARISSA; ANTOLINI, ERMETE; OLIVEIRA NETO, ALMIR
Carbon supported Pt nanoparticles were synthesized by the Flash Joule Heating Method (FJHM). An aqueous solution of Pt precursor H2PtCl6·6H2O was added to Vulcan XC 72 carbon into a reactor, and then this mixture was submitted to 50 cycles of discharges at 100 coulombs per discharge. Compared to a commercial Pt/C the X-ray Diffraction (XRD) analysis revealed an increase in the interplanar spacing of the platinum crystal lattice in the Pt/C catalyst prepared by FJHM, suggesting the emergence of structural defects. Transmission electronic microscopy (TEM) images showed distinct step-like features on the surface of FJHM-Pt/C, which may be indicative of structural defects, confirming X-ray Diffraction results. The cyclic voltammogram of the FJHM-Pt/C exhibited a significant increase in the oxidation pre-peak at 0.5 V compared to Pt/C BASF. Using pure H2 as the fuel, the single proton exchange membrane fuel cell with the commercial Pt/C as the anode catalyst showed a higher maximum power density (MPD) than FJHM-Pt/C. In the presence of CO with H2 the FJHM-Pt/C catalyst delivered a higher MPD compared to the cell with the commercial Pt/C. These results indicate an enhanced CO tolerance, underscoring the potential advantages of the FJHM preparation method.
Influence of reinforcing efficiency of clay on the mechanical properties of poly(butylene terephthalate) nanocomposite
2022 - COLOMBO, MARIA A.S.; DIAZ, FRANCISCO R.V.; KODALI, DEEPA; RANGARI, VIJAYA; GUVEN, OLGUN; MOURA, ESPERIDIANA A.B.
In contrast to the traditional fillers, clay, in particular, natural smectite clay represents an environmentally significant alternative to improve the properties of polymers. Compared to con-ventional nanofillers, smectite clay can effectively enhance the physical and mechanical properties of polymer nanocomposites with a relatively small amount of addition (< 5 wt%). The present study focuses on investigating the reinforcing efficiency of different amounts (up to 5 wt%) of a natural Brazilian smectite clay on the mechanical and thermal properties of poly(butylene terephthalate) (PBT) nanocomposites. Natural Brazilian clay modified by addition of quaternary salt and sodium carbonate (MBClay) was infused into the PBT polymer by melt extrusion, using a twin-screw extruder. It was found that the best properties for PBT were obtained at 3.7 wt% of modified BClay. Tensile strength at break exhibited an increase of about 60 %, flexural strength increased by 24 % and flexural modulus increased by 17 %. In addition, an increase in the crystallinity percentage of PBT/BClay nanocomposite was confirmed by DSC and XRD analysis, and a gain of about 45 % in HDT was successfully achieved due to incorporation of 3.7 wt% of MBClay.

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