INSTITUTO DE PESQUISAS ENERGÉTICAS E NUCLEARES
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Navegação Periódicos - Artigos por Agências de fomento "Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)"

Navegação Periódicos - Artigos por Agências de fomento "Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)"

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  • IPEN-DOC 25090

    FALCAO, R.B. ; DAMMANN, EDGAR D.C.C. ; ROCHA, C.J. ; DURAZZO, M. ; ICHIKAWA, R.U. ; MARTINEZ, L.G. ; BOTTA, W.J.; LEAL NETO, R.M. . An alternative route to produce easily activated nanocrystalline TiFe powder. International Journal of Hydrogen Energy, v. 43, n. 33, p. 16107-16116, 2018. DOI: 10.1016/j.ijhydene.2018.07.027

    Abstract: In this paper, an alternative process route to produce active nanocrystalline TiFe compound was investigated. First, TiH2 and Fe powders were dry co-milled in a planetary ball mill for 5e40 h. TiH2 was selected as precursor powder, instead of Ti powder, due its fragility, which has proved to be beneficial to decrease powders adherence on milling tools. In terms of loose powder mass, milling yields ranged from 90 to 95 wt.%. Next, milled powders were post-heated at 873 K under dynamic high-vacuum for TiFe synthesis reaction. First hydrogen absorption was verified in situ during the cooling process of samples (until the room temperature), being the amount of hydrogen absorbed and desorbed by this samples measured by automated Sievert's apparatus, under constant hydrogen flow rate of 9 cm3. min-1 (dynamic measurements). Besides to allowing the first absorption in situ, the investigated process route also allowed the production of the non-stoichiometric TiFe compound (rich in Ti) in samples milled for shorter times (5 and 10 h), both characteristics associated with maintaining the mechanical compound activity. Each sample absorbed hydrogen at 2 MPa during the cooling process, requiring no additional thermal activation cycles, since the samples milled for shorter times (mainly for 10 h) could absorb hydrogen for the first time more easily. However, the samples milled for longer times (25 and 40 h) shown better results in terms of reversible and storage capacities (0.73 and 0.94 wt.%, respectively).

    Palavras-Chave: nanostructures; powders; titanium hydrides; iron compounds; hydrides; milling; hydrogen storage

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  • IPEN-DOC 26862

    GARCIA, PAULO R.A.F.; PRYMAK, OLEG; GRASMIK, VIKTORIA; PAPPERT, KEVIN; WLYSSES, WAGNER; OTUBO, LARISSA ; EPPLE, MATTHIAS; OLIVEIRA, CRISTIANO L.P.. An in situ SAXS investigation of the formation of silver nanoparticles and bimetallic silver–gold nanoparticles in controlled wet-chemical reduction synthesis. Nanoscale Advances, v. 2, n. 1, p. 225-238, 2020. DOI: 10.1039/c9na00569b

    Abstract: We present a study on the formation of silver (Ag) and bimetallic silver–gold (AgAu) nanoparticlesmonitored by in situ SAXS as well as by ex situ TEM, XRD and UV-vis analysis in a flow reactor at controlled reaction temperature. The formation mechanism of the nanoparticles is derived from the structural parameters obtained from the experimental data. The evolution of the average particle size of pure and alloyed nanoparticles shows that the particle growth occurs initially by a coalescence mechanism. The later growth of pure silver nanoparticles is well described by Ostwald ripening and for the alloyed nanoparticles by a process with a significantly slower growth rate. Additionally, the SAXS data of pure silver nanoparticles revealed two major populations of nanoparticles, the first one with a continuous crystal growth to a saturation plateau, and the second one probably with a continuous emergence of small new crystals. The particle sizes obtained by SAXS agree well with the results from transmission electron microscopy and X-ray diffraction. The present study demonstrates the capability of an in situ investigation of synthesis processes using a laboratory based SAXS instrument. Online monitoring of the synthesis permitted a detailed investigation of the structural evolution of the system.

    Palavras-Chave: nanoparticles; small angle scattering; x-ray diffraction; silver; bimetals; gold; monte carlo method; nanostructures; alloys

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  • IPEN-DOC 25206

    FREITAS, LUCAS F. de ; VARCA, GUSTAVO H.C. ; BATISTA, JORGE G. dos S. ; LUGAO, ADEMAR B. . An overview of the synthesis of gold nanoparticles using radiation technologies. Nanomaterials, v. 8, n. 11, 2018. DOI: 10.3390/nano8110939

    Abstract: At a nano-level, optical properties of gold are unique and gave birth to an emerging platform of nanogold-based systems for diverse applications, because gold nanoparticle properties are tunable as a function of size and shape. Within the available techniques for the synthesis of gold nanoparticles, the radiolytic synthesis allows proper control of the nucleation process without the need for reducing agents, in a single step, combined or not with simultaneous sterilization. This review details and summarizes the use of radiation technologies for the synthesis and preparation of gold nanoparticles concerning fundamental aspects, mechanism, current pathways for synthesis and radiation sources, as well as briefly outlines final applications and some toxicity aspects related to nanogold-based systems.

    Palavras-Chave: gold; nanoparticles; gamma radiation; electron beams; x-ray sources; radiolysis; nanotechnology; medicine; diagnostic uses; ionizing radiations

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  • IPEN-DOC 29845

    GASPARIAN, P.B.R. ; MALTHEZ, A.L.M.C.; MARIANO, L.; CAMPOS, L.L. ; POLITANO, R. . An overview study on the TL and OSL dosimetry patent processes over time. Brazilian Journal of Radiation Sciences, v. 11, n. 1, p. 1-15, 2023. DOI: 10.15392/2319-0612.2023.2107

    Abstract: Since its discovery, ionizing radiation has been used in many different applications. Materials and methods have been developed to measure and quantify radiation doses. Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) are two techniques used for radiation dosimetry. Both TL and OSL are primarily applied in several areas, such as dating of ancient materials, equipment quality control and individual monitoring. One of the parameters to measure the knowledge and development of a technology is the number of patents related to the field. In this work, we established a methodology for patent search on the World Intellectual Property Organization (WIPO) database aiming to review the development of TL and OSL dosimetry over time. We concluded that along with the OSL technique development, the TL technique should continue to be explored in radiation dosimetry.

    Palavras-Chave: dosimetry; patents; thermoluminescence; property management; photoluminescence

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  • IPEN-DOC 27582

    LIMA, CAROLINE S.A. de ; BALOGH, TATIANA S. ; VARCA, JUSTINE P.R.O. ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. ; CAMACHO-CRUZ, LUIS A.; BUCIO, EMILIO; KADLUBOWSKI, SLAWOMIR S.. An updated review of macro, micro, and nanostructured hydrogels for biomedical and pharmaceutical applications. Pharmaceutics, v. 12, n. 10, p. 1-28, 2020. DOI: 10.3390/pharmaceutics12100970

    Abstract: Hydrogels are materials with wide applications in several fields, including the biomedical and pharmaceutical industries. Their properties such as the capacity of absorbing great amounts of aqueous solutions without losing shape and mechanical properties, as well as loading drugs of different nature, including hydrophobic ones and biomolecules, give an idea of their versatility and promising demand. As they have been explored in a great number of studies for years, many routes of synthesis have been developed, especially for chemical/permanent hydrogels. In the same way, stimuli-responsive hydrogels, also known as intelligent materials, have been explored too, enhancing the regulation of properties such as targeting and drug release. By controlling the particle size, hydrogel on the micro- and nanoscale have been studied likewise and have increased, even more, the possibilities for applications of the so-called XXI century materials. In this paper, we aimed to produce an overview of the recent studies concerning methods of synthesis, biomedical, and pharmaceutical applications of macro-, micro, and nanogels.

    Palavras-Chave: hydrogels; drugs; synthesis; cross-linking; skin; animal tissues; gamma radiation

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  • IPEN-DOC 29130

    SILVA, C.A.J. ; BRAGUIN, L.N.M. ; ROSSI, J.L. ; SCAPIN, M.A. ; COSTA, I. ; SAIKI, M. . Analyses of magnesium-based alloys by nuclear techniques. Brazilian Journal of Radiation Sciences, v. 10, n. 3B, p. 1-12, 2022. DOI: 10.15392/2319-0612.2022.1969

    Abstract: Magnesium-based alloys have been proposed for use in temporary biomaterials in the applications that request their biocompatibility and degradability. Analyses of these alloys are of great interest to verify if their element composition is within the product specification and also to evaluate the impurities that may cause toxic effects to the human health or influence in their corrosion processes. In this study, nuclear techniques of neutron activation analysis (NAA) and wavelength dispersive X ray fluorescence spectrometry (WD XRFS) were applied in the analyses of two magnesium-based alloys: commercially pure magnesium (CP-Mg) and AZ31 alloy. The NAA procedure consisted of irradiation aliquots of sample and synthetic element standards followed by measurements using a HGe detector and the WD XFRS was carried out using the Model RIX 3000 X-ray spectrometer. In the CP-Mg sample several element impurities were quantified. In the AZ31 alloy, the alloying element mass fractions were within the product specification and the impurities of As, La, Na and Sb were also quantified. Nickel and sulfur were quantified only by WD XFRS. The Horwitz method was a good parameter to evaluate the repeatability of the results in Al, Mg, Mn and Zn determinations. In conclusion, the results indicated the viability of using NAA and WD XFRS in the analyses of magnesium-based materials mainly due its multielement determinations, precision of the results, quantification of elements in a wide range of mass fractions and the lack of need for sample dissolution.

    Palavras-Chave: magnesium base alloys; biological materials; biodegradation; decomposition; fluorescence spectroscopy; x-ray fluorescence analysis; x radiation; specifications

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  • IPEN-DOC 26403

    OLIVEIRA, ALINE M. de; SOUZA, CRISTINA T.; OLIVEIRA, NARA P.M. de; MELO, ALINE K.S.; LOPES, FABIO J.S. ; LANDULFO, EDUARDO ; ELBERN, HENDRIK; HOELZEMANN, JUDITH J.. Analysis of atmospheric aerosol optical properties in the northeast Brazilian atmosphere with remote sensing data from MODIS and CALIOP/CALIPSO satellites, AERONET photometers and a ground-based Lidar. Atmosphere, v. 10, n. 10, p. 1-22, 2019. DOI: 10.3390/atmos10100594

    Abstract: A 12-year analysis, from 2005 to 2016, of atmospheric aerosol optical properties focusing for the first time on Northeast Brazil (NEB) was performed based on four di erent remote sensing datasets: the Moderate Resolution Imaging Spectroradiometer (MODIS), the Aerosol Robotic Network (AERONET), the Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP) and a ground-based Lidar from Natal. We evaluated and identified distinct aerosol types, considering Aerosol Optical Depth (AOD) and Angström Exponent (AE). All analyses show that over the NEB, a low aerosol scenario prevails, while there are two distinct seasons of more elevated AOD that occur every year, from August to October and January to March. According to MODIS, AOD values ranges from 0.04 to 0.52 over the region with a mean of 0.20 and occasionally isolated outliers of up to 1.21. Aerosol types were identified as sea spray, biomass burning, and dust aerosols mostly transported from tropical Africa. Three case studies on days with elevated AOD were performed. All cases identified the same aerosol types and modeled HYSPLIT backward trajectories confirmed their source-dependent origins. This analysis is motivated by the implementation of an atmospheric chemistry model with an advanced data assimilation system that will use the observational database over NEB with the model to overcome high uncertainties in the model results induced by still unvalidated emission inventories.

    Palavras-Chave: aerosols; aerosol monitoring; optical radar; dusts; datasets; satellites; atmospherics; meteorology; optical properties; brazil; atmospheric circulation

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  • IPEN-DOC 24335

    DURAZZO, MICHELANGELO ; SALIBA-SILVA, ADONIS M. ; GARCIA, RAFAEL H.L. ; CARVALHO, ELITA F.U. de ; RIELLA, HUMBERTO G.. Analysis of slag formation during UF4 magnesiothermic reduction. Nuclear Technology, v. 200, n. 2, p. 170-176, 2017. DOI: 10.1080/00295450.2017.1353870

    Abstract: Metallic uranium is a fundamental raw material for producing nuclear fuel elements for research reactors and irradiation targets for producing 99Mo, as U3Si2, UMo alloy, UAlx, and uranium thin foils. Magnesiothermic reduction of UF4 is a possible route in the nuclear fuel cycle for producing uranium as a metal ingot. The main concern about the reducing scale to produce low-enriched (metallic) uranium (LEU) (around 1 kg) is the relatively low yield compared to calciothermic reduction. Nevertheless, the magnesiothermic reduction has the advantages of having lower cost and being a safer method for dealing with uranium processing. The magnesiothermic process, as a batch, is closed inside a sealed crucible. In the present study, in order to have a qualitative idea of the kinetics during the ignition moment, the slag projected over the lateral inner face of the crucible was used to sketch the general magnesiothermic evolution. The methods used were metallographic observation and X-ray diffraction followed by Rietveld refinement. The results of these analyses led to the conception of a general reaction development during the short time between the ignition of the reducing reaction and final settlement of the products. Relevant information from this study led to the conclusion that uranium is not primarily present in the lateral slag projection over the crucible during the reaction, and the temperature level may reach 1500°C or more, after the ignition.

    Palavras-Chave: fissionable materials; fuel cycle; fuel cycle centers; magnesium; reduction; nuclear fuels; nuclear materials management; management; uranium; metallography; x-ray diffraction

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  • IPEN-DOC 24711

    BATISTA, RAFAEL M. ; MUCCILLO, E.N.S. . Analysis of the sintering process in gadolinia-doped ceria by thermodilatometry and correlation with microstructure evolution. Journal of Thermal Analysis and Calorimetry, v. 132, n. 2, p. 851-857, 2018. DOI: 10.1007/s10973-018-6969-5

    Abstract: The non-isothermal sintering process of cerium dioxide containing gadolinium sesquioxide powders within a wide range of specific surface area was investigated by dilatometry. Linear shrinkage data of powder compacts were recorded under several constant rates of heating. Dilatometry data were analyzed by two methodologies enabling to preview the relative density for any temperature/time profile, and determination of the apparent activation energy for sintering. Correlation of dilatometry results with microstructure evolution was also carried out. Remarkable differences in sintering powders with different specific surface areas were found. The apparent activation energy for sintering increases with decreasing specific surface area and, in most cases, it does not change significantly in the approximately 70-85% range of relative density.

    Palavras-Chave: microstructure; gadolinium oxides; cerium oxides; activation energy; simulation; heat rate; dilatometry; specific surface area; doped materials; sintering

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  • IPEN-DOC 26404

    MOREIRA, GREGORI de A. ; LOPES, FABIO J. da S. ; GUERRERO-RASCADO, JUAN L.; SILVA, JONATAN J. da ; GOMES, ANTONIO A. ; LANDULFO, EDUARDO ; ALADOS-ARBOLEDAS, LUCAS. Analyzing the atmospheric boundary layer using high-order moments obtained from multiwavelength lidar data: impact of wavelength choice. Atmospheric Measurement Techniques, v. 12, n. 8, p. 4261-4276, 2019. DOI: 10.5194/amt-12-4261-2019

    Abstract: The lowest region of the troposphere is a turbulent layer known as the atmospheric boundary layer (ABL) and characterized by high daily variability due to the influence of surface forcings. This is the reason why detecting systems with high spatial and temporal resolution, such as lidar, have been widely applied for researching this region. In this paper, we present a comparative analysis on the use of lidar-backscattered signals at three wavelengths (355, 532 and 1064 nm) to study the ABL by investigating the highorder moments, which give us information about the ABL height (derived by the variance method), aerosol layer movement (skewness) and mixing conditions (kurtosis) at several heights. Previous studies have shown that the 1064 nm wavelength, due to the predominance of particle signature in the total backscattered atmospheric signal and practically null presence of molecular signal (which can represent noise in high-order moments), provides an appropriate description of the turbulence field, and thus in this study it was considered a reference. We analyze two case studies that show us that the backscattered signal at 355 nm, even after applying some corrections, has a limited applicability for turbulence studies using the proposed methodology due to the strong contribution of the molecular signature to the total backscatter signal. This increases the noise associated with the high-order profiles and, consequently, generates misinformation. On the other hand, the information on the turbulence field derived from the backscattered signal at 532 nm is similar to that obtained at 1064 nm due to the appropriate attenuation of the noise, generated by molecular component of backscattered signal by the application of the corrections proposed.

    Palavras-Chave: troposphere; optical radar; boundary layers; atmospheres; aerosols; turbulence; air quality; monitoring

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  • IPEN-DOC 29836

    MOREIRA, GREGORI de A. ; CACHEFFO, ALEXANDRE ; ANDRADE, IZABEL da S. ; LOPES, FABIO JULIANO da S. ; GOMES, ANTONIO A. ; LANDULFO, EDUARDO . Analyzing the influence of vehicular traffic on the concentration of pollutants in the city of São Paulo: an approach based on pandemic SARS-CoV-2 data and deep learning. Atmosphere, v. 14, n. 10, p. 1-16, 2023. DOI: 10.3390/atmos14101578

    Abstract: This study employs surface and remote sensing data jointly with deep learning techniques to examine the influence of vehicular traffic in the seasonal patterns of CO, NO2 , PM2.5, and PM10 concentrations in the São Paulo municipality, as the period of physical distancing (March 2020 to December 2021), due to SARS-CoV-2 pandemic and the resumption of activities, made it possible to observe significant variations in the flow of vehicles in the city of São Paulo. Firstly, an analysis of the planetary boundary layer height and ventilation coefficient was performed to identify the seasons’ patterns of pollution dispersion. Then, the variations (from 2018 to 2021) of the seasonal average values of air temperature, relative humidity, precipitation, and thermal inversion occurrence/position were compared to identify possible variations in the patterns of such variables that would justify (or deny) the occurrence of more favorable conditions for pollutants dispersion. However, no significant variations were found. Finally, the seasonal average concentrations of the previously mentioned pollutants were compared from 2018 to 2021, and the daily concentrations observed during the pandemic period were compared with a model based on an artificial neural network. Regarding the concentration of pollutants, the primarily sourced from vehicular traffic (CO and NO2 ) exhibited substantial variations, demonstrating an inverse relationship with the rate of social distancing. In addition, the measured concentrations deviated from the predictive model during periods of significant social isolation. Conversely, pollutants that were not primarily linked to vehicular sources (PM2.5 and PM10) exhibited minimal variation from 2018 to 2021; thus, their measured concentration remained consistent with the prediction model.

    Palavras-Chave: urban areas; air pollution; air quality; machine learning; vehicles; coronaviruses

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  • IPEN-DOC 24325

    DOMIENIKAN, C. ; BOSCH-SANTOS, B. ; CABRERA-PASCA, G.A.; SAXENA, R.N. ; CARBONARI, A.W. . Anomalous behavior of the magnetic hyperfine field at 140Ce impurities at La sites in LaMnSi2. AIP Advances, v. 8, n. 5, p. 055702-1 - 055702-6, 2018. DOI: 10.1063/1.5006897

    Abstract: Magnetic hyperfine field has been measured in the orthorhombic intermetallic compound LaMnSi2 with perturbed angular correlation (PAC) spectroscopy using radioactive 140La(140Ce) nuclear probes. Magnetization measurements were also carried out in this compound with MPSM-SQUID magnetometer. Samples of LaMnSi2 compound were prepared by arc melting the component metals with high purity under argon atmosphere followed by annealing at 1000°C for 60 h under helium atmosphere and quenching in water. X-ray analysis confirmed the samples to be in a single phase with correct crystal structure expected for LaMnSi2 compound. The radioactive 140La (T1/2 = 40 h) nuclei were produced by direct irradiation of the sample with neutrons in the IEA-R1 nuclear research reactor at IPEN with a flux of ∼ 1013 n cm−2s−1 for about 3 - 4 min. The PAC measurements were carried out with a six BaF2 detector spectrometer at several temperatures between 10 K and 400 K. Temperature dependence of the hyperfine field, Bhf was found to be anomalous. A modified two-state model explained this anomalous behavior where the effective magnetic hyperfine field at 140Ce is believed to have two contributions, one from the unstable localized spins at Ce impurities and another from the magnetic Mn atoms of the host. The competition of these two contributions explains the anomalous behavior observed for the temperature dependence of the magnetic hyperfine field at 140Ce. The ferromagnetic transition temperature (TC) of LaMnSi2 was determined to be 400(1) K confirming the magnetic measurements.

    Palavras-Chave: cerium 140; impurities; iear-1 reactor; magnetic fields; hyperfine structure; crystal field; intermetallic compounds

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  • IPEN-DOC 29885

    CASAGRANDE, FERNANDA; FINOTTI, ELISANGELA; SOUZA, RONALD B. de; MOURA, REGIANE; LEONARDO, NOELI F.. Antarctic sea ice concentration in the Brazilian Earth System Model Simulations. Journal of Geoscience and Environment Protection, v. 11, n. 9, p. 1-19, 2023. DOI: 10.4236/gep.2023.119001

    Abstract: Sea ice is an important and complex component of the Earth’s system, acting as both an indicator and an amplifier of climate change. Here, we investigated the ability of the Brazilian Earth System Model (BESM-OA2.5) and four state-of-the-art climate models participating in the fifth phase of the Coupled Model Intercomparison Project, Version 5 (CMIP5) to represent the Antarctic Sea Ice Concentration (SIC) seasonal cycle. We validated the sea ice model’s performance using satellite data from 1980 to 2005 and calculated the skill and RMSE of each model. BESM-OA2.5 results for melt-freeze transitions in the Southern Ocean are consistent with CMIP5 models and satellite data. In February, when the sea ice reaches its annual minimum, the BESM-OA2.5 has the best fit among the models. However, in September, when the Antarctic sea ice reaches its annual maximum, the SIC simulated by BESM-OA2.5 indicated the largest area covered by ice compared to satellite, particularly on the Polar Front. Similar results were found in the CMIP5 models evaluated here. We suggest that the large bias simulated in the Polar Front is related to the inability of the sea ice model to represent the complex ocean- atmosphere-sea ice interactions. The subject is considered a hot topic in climate change studies and lacks conclusive answers.

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  • IPEN-DOC 29112

    SILVA, WILMAR D. da; ANDRADE, SONIA A. de; MEGALE, ANGELA A.A.; SOUZA, DANIEL A. de; SANTANNA, OSVALDO A.; MAGNOLI, FABIO C.; GUIDOLIN, FELIPE R.; GODOI, KEMILY S.; SALADINI, LUCAS Y.; SPENCER, PATRICK J. ; PORTARO, FERNANDA C.V.. Antibodies as snakebite antivenoms: past and future. Toxins, v. 14, n. 9, p. 1-13, 2022. DOI: 10.3390/toxins14090606

    Abstract: Snakebite envenomation is considered a neglected tropical disease, affecting tens of thousands of people each year. The recommended treatment is the use of antivenom, which is composed of immunoglobulins or immunoglobulin fragments obtained from the plasma of animals hyperimmunized with one (monospecific) or several (polyspecific) venoms. In this review, the efforts made in the improvement of the already available antivenoms and the development of new antivenoms, focusing on snakes of medical importance from sub-Saharan Africa and Latin America, are described. Some antivenoms currently used are composed of whole IgGs, whereas others use F(ab’)2 fragments. The classic methods of attaining snake antivenoms are presented, in addition to new strategies to improve their effectiveness. Punctual changes in immunization protocols, in addition to the use of cross-reactivity between venoms from different snakes for the manufacture of more potent and widely used antivenoms, are presented. It is known that venoms are a complex mixture of components; however, advances in the field of antivenoms have shown that there are key toxins that, if effectively blocked, are capable of reversing the condition of in vivo envenomation. These studies provide an opportunity for the use of monoclonal antibodies in the development of new-generation antivenoms. Thus, monoclonal antibodies and their fragments are described as a possible alternative for the production of antivenoms, regardless of the venom. This review also highlights the challenges associated with their development.

    Palavras-Chave: antibodies; toxins; venoms; snakes; disease; immunoglobulins

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  • IPEN-DOC 27584

    ANJOS, CAROLINA dos; SELLERA, FABIO P.; RIBEIRO, MARTHA S. ; BAPTISTA, MAURICIO S.; POGLIANI, FABIO C.; LINCOPAN, NILTON; SABINO, CAETANO P.. Antimicrobial blue light and photodynamic therapy inhibit clinically relevant β-lactamases with extended-spectrum (ESBL) and carbapenemase activity. Photodiagnosis and Photodynamic Therapy, v. 32, p. 1-4, 2020. DOI: 10.1016/j.pdpdt.2020.102086

    Abstract: Introduction. The production of β-lactamases by Gram-negative bacteria is among the most important factors of resistance to antibiotics, which has contributed to therapeutic failures that currently threaten human and veterinary medicine worldwide. Antimicrobial photodynamic therapy and antimicrobial blue light have a broad-spectrum antibacterial activity against multidrug-resistant and hypervirulent pathogens. Objective. To investigate the ability of antimicrobial blue light to inhibit the hydrolytic activity of clinically relevant β-lactamase enzymes (i.e., KPC, IMP, OXA, CTX-M, and SHV), with further comparison of the inhibitory effects of antimicrobial blue light with methylene blue-mediated antimicrobial photodynamic therapy. Methods. Blue LED light (λ = 410 ± 10 nm) alone or red LED light (λ = 660 ± 10 nm) in combination with methylene blue were used to inactivate, in vitro, suspensions of Klebsiella pneumoniae strains producing clinically important β-lactamase enzymes assigned to the A, B and D Ambler molecular classes. Furthermore, β-lactamase activity inhibition mediated by antimicrobial blue light and methylene blue-mediated antimicrobial photodynamic therapy was measured by using the chromogenic β-lactam substrate nitrocefin. Results. β-lactamase activities were effectively inactivated by both visible light-based approaches. In this regard, antimicrobial blue light and methylene blue-antimicrobial photodynamic therapy led to a significant reduction in the hydrolysis of nitrocefin (81–98 %). Conclusion. Sublethal doses of antimicrobial blue light and methylene blue-mediated antimicrobial photodynamic therapy are equally effective to inhibit clinically significant β-lactamases, including extended-spectrum β-lactamases and carbapenemases.

    Palavras-Chave: antimicrobial agents; methylene blue; antibiotics; lactams; inactivation; enzymes

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  • IPEN-DOC 28869

    BOTOSSO, VIVIANE F.; JORGE, SORAIA A.C.; ASTRAY, RENATO M.; GUIMARAES, ANA M. de S.; MATHOR, MONICA B. ; CARNEIRO, PATRICIA dos S. de; DURIGON, EDISON L.; COVAS, DIMAS; OLIVEIRA, DANIELLE B.L. de; OLIVEIRA, RICARDO das N.; MARIA, DURVANEI A.; ETO, SILAS F.; GALLINA, NEUZA M.F.; PIDDE, GISELLE; SQUAIELLA‑BAPTISTAO, CARLA C.; SILVA, DILZA T.; VILLAS‑BOAS, ISADORA M.; FERNANDES, DAYANNE C.; AUADA, ALINE V.V.; BANARI, ALEXANDRE C.; SOUZA FILHO, ANTONIO F. de; BIANCONI, CAMILA; UTESCHER, CARLA L. de A.; OLIVEIRA, DENISE C.A.; MARIANO, DOUGLAS O.C.; BARBOSA, FLAVIA F.; RONDON, GIULIANA; KAPRONEZAI, JOSANA; SILVA, JULIANA G. da; GOLDFEDER, MAURICIO B.; COMONE, PRISCILA; CASTILHO JUNIOR, REGIS E.; PEREIRA, TAIANA T.S.; WEN, FAN H.; TAMBOURGI, DENISE V.; CHUDZINSKI‑TAVASSI, ANA M.. Anti‑SARS‑CoV‑2 equine F (Ab′)2 immunoglobulin as a possible therapy for COVID‑19. Scientific Reports, v. 12, p. 1-17, 2022. DOI: 10.1038/s41598-022-07793-1

    Abstract: The new outbreak of coronavirus disease 2019 (COVID-19) has infected and caused the death of millions of people worldwide. Intensive efforts are underway around the world to establish effective treatments. Immunoglobulin from immunized animals or plasma from convalescent patients might constitute a specific treatment to guarantee the neutralization of the virus in the early stages of infection, especially in patients with risk factors and a high probability of progressing to severe disease. Worldwide, a few clinical trials using anti-SARS-CoV-2 immunoglobulins from horses immunized with the entire spike protein or fragments of it in the treatment of patients with COVID-19 are underway. Here, we describe the development of an anti-SARS-CoV-2 equine F(ab′)2 immunoglobulin using a newly developed SARS-CoV-2 viral antigen that was purified and inactivated by radiation. Cell-based and preclinical assays showed that the F(ab′)2 immunoglobulin successfully neutralizes the virus, is safe in animal models, and reduces the severity of the disease in a hamster model of SARS-CoV-2 infection and disease.

    Palavras-Chave: immunoglobulins; coronaviruses; viral diseases; horses; therapy; plasma; antibody formation

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  • IPEN-DOC 29514

    SILVA FILHO, JORGE C.; SILVA, SUELANNY C. da; VENANCIO, EVERALDO C.; TAKIISHI, HIDETOSHI ; ABE, IGOR Y.; SOARES, EDSON P. ; ANTUNES, RENATO A.; REY, JOSE F.Q.; MARTINEZ, LUIS G. ; ESCOTE, MARCIA T.. Aplicação de derivados de grafeno em baterias e ímãs permanentes / Application of graphene derivatives in batteries and permanent magnets. Revista da ABPN, v. 14, n. 41, p. 124-142, 2022. DOI: 10.31418/2177-2770.2022.v14.n41.p124-142

    Abstract: O presente trabalho aborda o estudo sobre a importância tecnológica dos compostos de grafeno, evidenciando a síntese, a caracterização do óxido de grafeno (GO) e óxido de grafeno reduzido (rGO) e suas aplicações em baterias e imãs permanentes de neodímio-ferro-boro. Os resultados de difração de raios-X mostraram a presença de apenas um pico em aproximadamente 2θ = 11°, o qual corresponde ao conjunto de planos de GO em (002). Os resultados das aplicações são: O eletrodo negativo da Bateria2 com 1% de adição de GO apresentou uma capacidade de descarga de 397,03 mAh/g e maior estabilidade cíclica durante os 30 ciclos. No caso dos imãs, o imã2, com 0,1% em massa de rGO mostrou os maiores valores de Br = 10,42 T, BHmax = 21,19 MGOe, ρ = 7135 kg m-3 e FQ = 0,63.

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  • IPEN-DOC 28849

    GODOI, CAMILA M. ; SANTOS, MONIQUE C.L. ; NUNES, LIVIA C. ; SILVA, ARACELI J. ; RAMOS, ANDREZZA S. ; SOUZA, RODRIGO F.B. de ; NETO, ALMIR O. . Application of binary PdSb/C as an anode in a polymeric electrolyte reactor-fuel cell type for electrosynthesis of methanol from methane. Materials Research, v. 25, p. 1-8, 2022. DOI: 10.1590/1980-5373-MR-2021-0542

    Abstract: PdSb catalyst prepared in different compositions were applied as an anode in a polymeric electrolyte reactor - fuel cell type (PER-FC) to convert methane into oxygenated products and energy in mild conditions. The PER-FC polarization curves for Pd90Sb10/C presented maximum current density about 0.92 mW cm-2 about 15% higher than PdSb materials. However, the material Pd50Sb50/C showed higher reaction rate for methanol generation than the other materials occurring close to the OCV (r ~ 7 mol L-1 h-1). The qualitative analyses of PER-FC effluent by FT-IR identified products as methanol, carbonate and formate ions from the partial oxidation of methane for all materials.

    Palavras-Chave: antimony; catalysts; cogeneration; current density; electrolytic cells; fourier transformation; fuel cells; methane; methanol; oxidation; palladium

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  • IPEN-DOC 25738

    ROVANI, S. ; MEDEIROS, L.F.; LIMA, E.C.; FERNANDES, A.N.. Application of biochar from agro‑industrial waste in solid‑phase extraction for the determination of 17β‑estradiol from aqueous solution. International Journal of Environmental Science and Technology, v. 16, n. 12, p. 7623-7630, 2019. DOI: 10.1007/s13762-019-02295-6

    Observação: Correction anexado. International Journal of Environmental Science and Technology, v. 16, p. 7631, 2019. DOI: 10.1007/s13762-019-02433-0

    Abstract: In this study, the biochar produced from coffee wastes and eucalyptus sawdust was employed as an adsorbent in solid-phase extraction devices for the determination of 17β-estradiol from aqueous solution. Parameters such as adsorbent mass, solvent type, eluent volume, ionic strength, breakthrough volume, and the cartridge reuse were evaluated. The best experimental conditions for solid-phase extraction concerning adsorbent mass, elution solvent, eluent volume, ionic strength, breakthrough volume, and cartridge reuse were established. The most suitable conditions for 1.0-mL cartridge were: mass of 50 mg, elution solvent 5.0 mL of acetonitrile/water 90:10 (v:v), 0.003 mol L−1 NaCl concentration, and 17β-estradiol solution volume 50.0 mL. The solid-phase extraction results showed that, although 17β-estradiol recovery was about 60%, the removal efficiency was 100% and the cartridges of 200 and 500 mg can be reused eight and four times, respectively, without any decrease in adsorption capacity. The results demonstrate the potential use of biochar as new adsorbent in solid-phase extraction devices for the removal of estrogens in aqueous solution.

    Palavras-Chave: charcoal; wood fuels; solid wastes; adsorbents; hormones; estradiol; agriculture; agricultural wastes

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  • IPEN-DOC 23215

    VILLANI, DANIEL; MANCINI, ANSELMO; HADDAD, CECILIA M.K.; CAMPOS, LETICIA L. . Application of optically stimulated luminescence ‘nanoDot’ dosimeters for dose verification of VMAT treatment planning using an anthropomorphic stereotactic end-to-end verification phantom. Radiation Measurements, p. 1-5, 2017. DOI: 10.1016/j.radmeas.2017.03.027

    Abstract: This paper aims to evaluate the performance of the commercial OSL Landauer InLight System to be applied in dosimetric measurements in a Volumetric Modulated Arc (VMAT) brain tumor planning treatment using a Stereotactic End-To-End Verification Phantom Patient (STEEV™ – CIRS), comparing its results with CaSO4:Dy TLD pellets manufactured and marketed by the Laboratory of Dosimetric Materials/IPEN, PTW PinPoint™ ion chamber and Eclipse 10.0 planning system. The results of commercial InLight™ System using the nanoDot dosimeters showed good reproducibility and stability in both laboratory and clinical measurements. The experimental dose values obtained by all dosimetric techniques varied less than ±1.0% from prescribed by Eclipse 10.0. The intrinsic precision and uncertainty of the OSL reading device were found fair enough, providing good experimental results for VMAT dosimetry.

    Palavras-Chave: thermoluminescent dosemeters; photoluminescence; volumetric analysis; radiotherapy; dosimetry

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A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

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