Abstract: Owing to the localized plasmon resonance of an ensemble of interacting plasmonic nanoparticles (NPs), there has been a tremendous drive to conceptualize complex optical nanocircuits with versatile functionalities. In comparison to modern research, there is still not a sufficient level of sophistication to treat the nanostructures as lumped circuits that can be adjusted into complex systems on the basis of a metatronic touchstone. Here, we present the design, assembly, and characterization of single relatively complex photonic nanocircuits by accurately positioning several metallic and dielectric nanoparticles acting as modular lumped elements. In this research, Au NPs along with silica NPs were used to compare the proficiency and precision of our lumped circuit model analytically. On increasing the size of an individual Au NP, the spectral peak resonance not only modifies but also causes more scattering efficiency which increases the fringe capacitance linearly and decreases the nanoinductance of lumped circuit element. The NPs-based assembly induced the required spectral resonance ascribed by simple circuit methods and are depicted to be actively reconfigurable by tuning the direction or polarization of input signals. Our work demonstrates a vital step toward developing the modern modular designing tools of complex electronic circuits into nanophotonic-related applications.

Palavras-Chave: plasmons; nanomaterials; elements; nanoparticles; electronic circuits

FAROOQ, SAJID; SHAFIQUE, SHAREEN; AHSAN, ZISHAN; CARDOZO, OLAVO; WALI, FAIZ. Tailoring the scattering response of optical nanocircuits using modular assembly. Nanomaterials, v. 12, n. 17, p. 1-12, 2022. DOI: 10.3390/nano12172962. Disponível em: http://repositorio.ipen.br/handle/123456789/33452. Acesso em: $DATA.

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Abstract: Background: Native-like secondary structures and biological activity have been described for proteins in inclusion bodies (IBs). Tertiary structure analysis, however, is hampered due to the necessity of mild solubilization conditions. Denaturing reagents used for IBs solubilization generally lead to the loss of these structures and to consequent reaggregation due to intermolecular interactions among exposed hydrophobic domains after removal of the solubilization reagent. The use of mild, non-denaturing solubilization processes that maintain existing structures could allow tertiary structure analysis and increase the efficiency of refolding. Results: In this study we use a variety of biophysical methods to analyze protein structure in human growth hormone IBs (hGH-IBs). hGH-IBs present native-like secondary and tertiary structures, as shown by far and near-UV CD analysis. hGH-IBs present similar λmax intrinsic Trp fluorescence to the native protein (334 nm), indicative of a native-like tertiary structure. Similar fluorescence behavior was also obtained for hGH solubilized from IBs and native hGH at pH 10.0 and 2.5 kbar and after decompression. hGH-IBs expressed in E. coli were extracted to high yield and purity (95%) and solubilized using non-denaturing conditions [2.4 kbar, 0.25 M arginine (pH 10), 10 mM DTT]. After decompression, the protein was incubated at pH 7.4 in the presence of the glutathione-oxidized glutathione (GSH-GSSG) pair which led to intramolecular disulfide bond formation and refolded hGH (81% yield). Conclusions: We have shown that hGH-IBs present native-like secondary and tertiary structures and that non-denaturing methods that aim to preserve them can lead to high yields of refolded protein. It is likely that the refolding process described can be extended to different proteins and may be particularly useful to reduce the pH required for alkaline solubilization.

Palavras-Chave: proteins; hormones; pressure dependence; ph value

CHURA-CHAMBI, ROSA M.; FARAH, CHUCK S.; MORGANTI, LIGIA. Human growth hormone inclusion bodies present native‑like secondary and tertiary structures which can be preserved by mild solubilization for refolding. Microbial Cell Factories, v. 21, n. 1, p. 1-10, 2022. DOI: 10.1186/s12934-022-01887-1. Disponível em: http://repositorio.ipen.br/handle/123456789/33450. Acesso em: $DATA.

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Abstract: We report a new experimental setup enabling local electrochemical impedance spectroscopy (LEIS) measurements over a wide frequency range, including the low frequency domain. First, an improved signal treatment was performed using a potential shifter to minimize the DC component of the measured potential, allowing for the local AC potential to be probed using an ideal electrochemical system. Then, a unique, three-electrode LEIS probe was implemented to study the influence of radial and lateral contributions on the LEIS response. The radial LEIS response is highest when the LEIS probe is positioned in the middle of the gold electrode substrate, whereas the lateral LEIS response is similar in both measured regions. Both experimental modifications were implemented to study the LEIS response over a corroding aluminum substrate, for which reliable results are obtained in the low frequencies. These tools could be used in future LEIS studies in other fields that require time-sensitive measurements.

Palavras-Chave: measuring methods; scanning electron microscopy; impedance; electrochemistry

GOMES, MAURILIO P.; GATEMAN, SAMANTHA M.; COSTA, ISOLDA; GHARBI, OUMAIMA; NGO, KIEU; ROSSI, JESUALDO L.; TURMINE, MIREILLE; VIVIER, VINCENT. Improved experimental setup to reach a broad frequency domain in local electrochemical impedance spectroscopy measurements. Measurement, v. 200, p. 1-10, 2022. DOI: 10.1016/j.measurement.2022.111504. Disponível em: http://repositorio.ipen.br/handle/123456789/33448. Acesso em: $DATA.

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Abstract: The aim of this work was to investigate the effect of galvanic coupling between stainless steel AISI 316 L abutment type Morse taper and implant made of ASTM F1108–14 Ti-6Al-4V alloy. The assembly of the two alloys was carried out using mechanical imbrication by means of successive strikes at 0.05 J force onto the abutment inserted in the implant along the centerline. Corrosion attack at the interface of the alloys was evaluated according to the number of strikes used for joining the parts. Corrosion resistance was evaluated for the samples by open circuit potential measurements as function of time and scanning vibrating electrode technique (SVET) and scanning ion selective electrode technique (SIET) in phosphate buffer solution with pH adjusted to 3.0, and into which hydrogen peroxide was added to simulate tissue inflammatory conditions. Samples were evaluated at the cross and longitudinal sections. Results indicated that the number of strikes used in assembling affected corrosion susceptibility. The lowest amount of corrosion products was associated to the highest number of strikes used. The corrosion resistance was related to the characteristics of the crevice between the implant and the abutment.

Palavras-Chave: dentistry; implants; titanium alloys; stainless steel-316l; morse potential; corrosion

BERBEL, LARISSA O.; VIVEIROS, BARBARA V.G. de; MICELLI, ANA L.P.; NIGRO, FREDERICO; ROSSI, JESUALDO L.; COSTA, ISOLDA. Corrosion mechanism of Ti-6Al-4V morse taper dental implants connected to 316 L stainless steel prosthetic abutment. Materials Today Communications, v. 33, p. 1-13, 2022. DOI: 10.1016/j.mtcomm.2022.104583. Disponível em: http://repositorio.ipen.br/handle/123456789/33446. Acesso em: $DATA.

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Abstract: Ti-34Nb-6Sn alloy were prepare by powder metallurgy milled in two different times (40 and 60 min) using Ti and Nb hydrides with or without Mg, as spacer then sintered at 700ºC and 800ºC. Characterizations were made by scanning electron microscope (SEM), X-ray diffractometer (XRD) and by Archimedes. Microhardness was measured by Vickers microhardness. Mesenchymal stem cells derived from equine bone marrow (BMMSCs) were used to evaluate the sample cytotoxicity. Hydration and dehydration process was confirmed, also the formation of brittle particles during the milling. Materials were structured under α and β phase, and the samples that received Mg as a spacer had slightly lower β phase content compared to samples without Mg, suggesting difficult α→β transformation due to the presence of barriers formed by pores. Mg provided greater porosity, and prepared milled in a shorter time promoted an increase in the macropores. Microhardness was similar to that of commercial materials (i.e., CP-Ti and also to other alloys with similar nominal composition. Cells treated with conditioned medium with the samples showed viability comparable to the control group, and after 48 h of culture on the samples, there was significant growth and more circular morphology, when adhered on materials that received Mg.

Palavras-Chave: biological materials; compatibility; magnesium alloys; microhardness; milling; niobium alloys; physical properties; powder metallurgy; tin alloys; titanium alloys; toxicity; x-ray diffraction

ROSSI, MARIANA C.; STIEVANI, FERNANDA de C.; PFEIFER, JOAO P.H.; MARTINEZ, LUIS G.; BORRAS, VICENTE A.; SAEKI, MARGARIDA J.; ALVES, ANA L.G. Evaluation of the physical and biological properties of Ti-34Nb-6Sn/Mg alloy obtained by powder metallurgy for use as biomaterial. Materials Research, v. 25, p. 1-15, 2022. DOI: 10.1590/1980-5373-MR-2021-0233. Disponível em: http://repositorio.ipen.br/handle/123456789/33444. Acesso em: $DATA.

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Abstract: The most used production route of Mo-99 is through the fission of U-235 in irradiation targets that are irradiated in research reactors. The annular target is a promisor design since it can incorporate high U-235 quantities, thus increasing the production yield of Mo-99. This target type uses a foil of uranium metal enveloped by a thin nickel foil that acts as a diffusion barrier. The process of uranium enveloping with nickel foil is today done manually. This operation risks the nickel foil breaking up during target assembling. In the present work, we studied the nickel electrodeposition over uranium metal foil surfaces to replace nickel foils. A pre-forming procedure of the uranium metal foil by calendering was developed to facilitate the assembling operation. The electrodeposition was done over the uranium foil pre-conformed in a tubular shape. An automated apparatus for electrodeposition of nickel in uranium tubular-shaped foil was developed. The results showed that the high nickel adherence to uranium metal depends on the proper activation of the uranium surface. Among the activation processes studied, the mechanical activation showed good adhesion of the nickel layer, with a loss of only 0.16% of uranium mass. Homogeneous and regular 12 μm thickness electrodeposited layers over the uranium metal were obtained. This work showed that the process could be used in continuous production technology, such as the production of irradiation targets.

Palavras-Chave: electrodeposition; molybdenum 99; nickel; uranium; foils; targets

IANELLI, RICARDO F.; SALIBA-SILVA, ADONIS M.; TAKARA, ERIKI M.; GARCIA NETO, JOSE; SOUZA, JOSE A.B.; CARVALHO, ELITA F.U. de; DURAZZO, MICHELANGELO. Nickel electrodeposition in LEU metal foil annular targets to produce Mo-99. Materials Chemistry and Physics, v. 290, p. 1-12, 2022. DOI: 10.1016/j.matchemphys.2022.126620. Disponível em: http://repositorio.ipen.br/handle/123456789/33442. Acesso em: $DATA.

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Abstract: Trindade is a remote island far from 1170 km of the Brazilian coast in the Atlantic Ocean, between South America and South Africa. The island has great biodiversity and scientific studies on the fauna and flora of Trindade are still scarce. Accordingly, since crustacean species of the island are also little known, this research features an unprecedented data set, which provides information on the level of potential toxic elements in two crab species: the Grapsus grapsus (herbivore) and the endemic species Gecarcinus lagostoma (omnivorous) which is in threatened status. Although Trindade has experienced contamination from human activities, mainly plastic debris, the element levels found in the samples suggest that there are no relevant inorganic sources into the island. Since minor and trace elements accumulated by marine invertebrates does not present a pattern behavior, our results can support other studies focused on the impact of global warming to the marine ecosystem.

Palavras-Chave: crabs; toxicity; toxic materials; seafood; elements; trace amounts

THEOPHILO, CAROLINA Y.S.; RIBEIRO, ANDREZA P.; TREVIZANI, TAILISI H.; MAJER, ALESSANDRA P.; MONTONE, ROSALINDA C.; RAKAUSKAS, FELIPE; ARRUDA, CLAUDIA S.C. de; MOREIRA, EDSON G.; FIGUEIRA, RUBENS C.L. Assessment of crabs from Trindade, a Brazilian remote island: support to marine studies. Marine Pollution Bulletin, v. 182, p. 1-8, 2022. DOI: 10.1016/j.marpolbul.2022.113922. Disponível em: http://repositorio.ipen.br/handle/123456789/33440. Acesso em: $DATA.

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Abstract: To evaluate the effect of fatigue and aging on the crystalline content and reliability of a zirconia-toughened-alumina (ZTA) composite compared to its individual counterpart materials (3Y-TZP and Al2O3). Thirty-six disc-shaped specimens per group were obtained to comply with ISO 6872:2015. Crystalline content, microstructure and reliability of experimental groups were evaluated in four stages: 1) immediate; 2) aged; 3) fatigued; 4) aged + fatigue. Aging was performed in autoclave and Step-Stress-Accelerated-Life-Testing (SSALT) was performed using three stress profiles. Weibull statistics were used to determine Weibull parameters and life-expectancy. A significant increase in monoclinic phase in 3Y-TZP was observed after aging (19.31%), fatigue (17.88%) and aging + fatigue (55.81%), while ZTA evidenced minimal variation among all conditions (<5.69%). 3Y-TZP presented higher reliability than ZTA at 300 and 500 MPa, and ZTA outperformed Al2O3 at the same stress missions. None of the ceramics yielded acceptable reliability at 800 MPa. A higher characteristic strength was observed for 3Y-TZP, followed by ZTA and Al2O3. While after aging ZTA and Al2O3 remained stable, 3Y-TZP exhibited a significant increase in the characteristic stress. Aging did not affect the reliability of ZTA and Al2O3. 3Y-TZP demonstrated an increase in monoclinic content and characteristic strength after aging.

Palavras-Chave: microstructure; aging; reliability; zirconium; aluminates; fatigue; fatigue

BENALCAZAR JALKH, ERNESTO B.; BERGAMO, EDMARA T.P.; CAMPOS, TIAGO M.B.; ARAUJO-JUNIOR, EVERARDO N.S. de; LOPES, ADOLFO C.O.; TEBCHERANI, SERGIO M.; YAMAGUCHI, SATOSHI; GENOVA, LUIS A.; GIERTHMUEHLEN, PETRA C.; WITEK, LUKASZ; COELHO, PAULO G.; BONFANTE, ESTEVAM A. Stability of fatigued and aged ZTA compared to 3Y-TZP and Al2O3 ceramic systems. Journal of the Mechanical Behavior of Biomedical Materials, v. 135, p. 1-9, 2022. DOI: 10.1016/j.jmbbm.2022.105451. Disponível em: http://repositorio.ipen.br/handle/123456789/33438. Acesso em: $DATA.

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Abstract: Statement of problem. Whether a computer-aided design and computer-aided manufacture (CAD-CAM) fabricated high-translucency lithium disilicate veneer on a lithium disilicate substructure would increase the strength of the restoration compared with a traditional feldspathic porcelain veneer is unclear. Purpose. The purpose of this in vitro study was to evaluate the effect of different lithium disilicate veneer application methods on a lithium disilicate substructure on their biaxial flexural stress (BFS). Material and methods. Lithium disilicate disks were fabricated so that when combined with the veneering disks, they had a dimension of 12×1.2 mm. Experimental groups were as follows (n=15): resin-bonded lithium disilicate veneer, lithium disilicate veneer adhesively cemented to lithium disilicate; sintered lithium disilicate veneer, lithium disilicate veneer sintered to lithium disilicate; sintered feldspathic veneer, feldspathic porcelain applied to lithium disilicate; and monolithic lithium disilicate, the control group. Weibull distribution survival analysis was used to compare the differences in the resistance to fracture after fatigue. The total number of cycles was analyzed by using 1-way ANOVA (α=.05). A finite element analysis (FEA) was also performed. The maximum principal stress (MPS) was used as the failure criterion. Results. The sintered feldspathic veneer group had significantly lower fatigue resistance than sintered lithium disilicate veneer or resin-bonded lithium disilicate veneer (P<.05). The resin-bonded lithium disilicate veneer group showed significantly more fractured fragments than the other groups. No statistical difference was observed in the number of cycles. The lithium disilicate veneered groups presented similar resistance to fatigue as the monolithic specimens of the same overall dimensions. Higher peaks of MPS were observed for groups monolithic lithium disilicate, sintered lithium disilicate veneer, and sintered feldspathic veneer than for resin-bonded lithium disilicate veneer. Conclusions. Veneering a lithium disilicate substructure with a lithium disilicate veneer, bonded or sintered, increased resistance to fatigue compared with a feldspathic porcelain veneer. The lithium disilicate veneer groups had similar fatigue resistance to that of the monolithic group.

Palavras-Chave: lithium; dentistry; ceramics; porcelain; computer graphics; lithium silicates

MAY, JAREN T.; ARATA, ANELYSE; COOK, NORMAN B.; DIEFENDERFER, KIM E.; LIMA, NELSON B.; BORGES, ALEXANDRE L.S.; FEITOSA, SABRINA. Stepwise stress testing of different CAD-CAM lithium disilicate veneer application methods applied to lithium disilicate substructures. Journal of Prosthetic Dentistry, v. 128, n. 4, p. 794-802, 2022. DOI: 10.1016/j.prosdent.2020.05.033. Disponível em: http://repositorio.ipen.br/handle/123456789/33436. Acesso em: $DATA.

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Abstract: Neutrons can be detected indirectly through a nuclear reaction where the products are ionizing radiation. Due to the shortage of 3He, several studies are searching for alternatives, where the Gas Electron Multiplier (GEM) detector using a layer of 10B as a neutron converter is a very promising option. The GEM detectors are a type of Micro-Pattern Gaseous Detectors (MPGD), widely used in particle tracking systems, as the Time Projection Chamber of the ALICE experiment in the LHC-CERN, and proposed for many other applications, including neutron detection. A common strategy to simulate this kind of detector is based on two frameworks: Geant4 and Garfield++. Given the high ionizing power of these nuclear reaction products, a full simulation is very time consuming then a fast simulator was developed using a parameterization strategy based on these two frameworks that allowed to generate enough data to study an optimized version of this detector. In this proceeding, it is shown the optimization that improves the position resolution by changing the gas mixture and/or its pressure.

Palavras-Chave: computer codes; computerized simulation; electron multiplier detectors; gases; he-3 counters; neutron detectors; nuclear reactions; radiation detectors; reactors; thermal neutrons

FELIX DOS SANTOS, R.; MUNHOZ, M.G.; MORALLES, M. Performance and optimization of a GEM-based neutron detector using a parameterized fast simulator. Journal of Physics: Conference Series, v. 2340, p. 1-6, 2022. DOI: 10.1088/1742-6596/2340/1/012048. Disponível em: http://repositorio.ipen.br/handle/123456789/33434. Acesso em: $DATA.

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Abstract: Melanoma is a highly aggressive skin cancer that requires new approaches for its management. Low-level laser therapy, currently named photobiomodulation therapy (PBM), has been used to improve different conditions but its effects and safe use on melanoma remain unexplored. Herein, we investigated the PBM impact on melanoma cells differing by pigmentation using near-infrared (NIR) and red lasers in vitro. In vivo, we evaluated the effects of the red laser on melanoma-bearing mice. Amelanotic (SK-MEL-37) and melanotic (B16F10) cells were exposed in vitro to a NIR (780 nm, 40 mW) or a red laser (660 nm, 40 mW) in 3 different light doses: 30, 90, and 150 J/cm2 and responses were assessed regarding mitochondrial activity, invasiveness, migration, and VEGF production. In vivo, melanoma-bearing mice received the red laser delivering 150 J/cm2 directly to the tumor on 3 consecutive days. Mice were monitored for 15 days regarding tumor progression and mouse survival. We noticed that amelanotic cells were unresponsive to NIR light. In contrast, NIR irradiation at 30 J/cm2 promoted an increase in the invasiveness of pigmented cells, even though all light doses have inhibited cell migration. Regarding the red laser on pigmented cells, the highest light dose (150 J/cm2) decreased the VEGF production and migration. In vivo, melanoma-bearing mice treated with red laser showed smaller tumor volume and longer survival than controls. We conclude that PBM appears to be safe for amelanotic non-pigmented melanoma but triggers different responses in melanotic pigmented cells depending on light parameters. Additionally, a high dose of red laser impairs the invasive behavior of melanoma cells, probably due to the decrease in VEGF synthesis, which may have contributed to tumor arrest and increased mouse survival. These findings suggest that red laser therapy could be a new ally in the supportive care of melanoma patients.

Palavras-Chave: neoplasms; melanomas; skin diseases; laser radiation; therapy; clinical trials

CONTATORI, CAROLINA G. de S.; SILVA, CAMILA R.; PEREIRA, SAULO de T.; RODRIGUES, MARIA F.S.D.; LUNA, ARTHUR C. de L.; MARQUES, MARCIA M.; RIBEIRO, MARTHA S. Responses of melanoma cells to photobiomodulation depend on cell pigmentation and light parameters. Journal of Photochemistry and Photobiology B: Biology, v. 235, p. 1-11, 2022. DOI: 10.1016/j.jphotobiol.2022.112567. Disponível em: http://repositorio.ipen.br/handle/123456789/33432. Acesso em: $DATA.

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Abstract: This study presents a systematic analysis of the influence of irradiation conditions (absorbed dose, temperature, and atmosphere) on the physicochemical properties of radiation-induced grafted anion-exchange membranes (AEMs) based on low-density polyethylene (LDPE). Detailed characterization of the polymeric electrolytes shows striking effects of the irradiation conditions on the AEM properties. The LDPE films are irradiated both at room temperature (RT) and low temperature (LT, ∼ −10 °C). At each temperature, samples are irradiated in air as well as nitrogen. By lowering the sample temperature from RT to LT during irradiation in air it is possible to obtain a threefold increase in the degree of grafting (DoG). The higher DoG reflects in the OH− conductivity (σ) of the AEM irradiated at LT, which exhibits σ (T = 80 °C) = 215 mS cm−1, while the sample prepared at RT and air has σ (T = 80 °C) = 127 mS cm−1. Such high conductivity of the LT irradiated LDPE-AEM results in high-performance anion-exchange membrane fuel cell (AEMFC) with enhanced stability, as inferred from the time dependence of σ (T = 60 °C) measurements. The experimental results evidence that the control of both the irradiation temperature and the atmosphere diminishes the degradation effects caused by the radiation. Therefore, the present study advances the understanding of the role played by the irradiation process on the final properties of radiation-induced grafted LDPE-based AEMs and offers new possibilities to guide future developments for anion-exchange membranes.

Palavras-Chave: polyethylenes; density; anions; ion exchange; membranes; fuel cells

BARBOSA, ANDREY S.; BIANCOLLI, ANA L.G.; LANFREDI, ALEXANDRE J.C.; RODRIGUES JUNIOR, ORLANDO; FONSECA, FABIO C.; SANTIAGO, ELISABETE I. Enhancing the durability and performance of radiation-induced grafted low-density polyethylene-based anion-exchange membranes by controlling irradiation conditions. Journal of Membrane Science, v. 659, p. 1-12, 2022. DOI: 10.1016/j.memsci.2022.120804. Disponível em: http://repositorio.ipen.br/handle/123456789/33430. Acesso em: $DATA.

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Abstract: Hydrogels for wound dressings are usually developed for contact surfaces where mechanical properties are conveniently required. In this sense nanocomposite hydrogels based on PVAl (poly(vinyl alcohol) and PVP (poly(N-2-vinil-pirrolidone)) containing 0.5-1.5 wt% of the synthetic laponite RD clay were prepared by a gamma radiation process and compared with similar membranes composed separately of PVP or PVAl. This study aimed to evaluate the effect of clay on the properties and the differences of the polymer blend instead of a unique polymer. The morphology of the hydrogels was evaluated by spectrometric techniques using XRD (X-ray diffraction), SEM (scanning electron microscopy), swelling assay, and FTIR (infrared spectroscopy). The swelling kinetics at 22 °C and the mechanical properties by a tensile test comprised the structural properties that were assessed. The results showed PVA/PVP network depends directly on the clay concentration in the nanocomposite hydrogels. The blend PVP/PVAl proved to have potentially efficient mechanical properties for drug delivery in the treatment of wounds.

Palavras-Chave: drug delivery; clays; hydrogels; nanocomposites

OLIVEIRA, MARIA J.A.; SANTOS, VINICIUS J.; FREITAS, LUCAS F. de; LUGAO, ADEMAR B.; PARRA, DUCLERC F. Poly(vinyl alcohol) (PVAl) and poly(N-2-vinyl-pyrrolidone) hydrogels nanostructured by laponite clay for drug delivery. Journal of Materials Science and Engineering B, v. 12, n. 7-9, p. 97-107, 2022. DOI: 10.17265/2161-6221/2022.7-9.003. Disponível em: http://repositorio.ipen.br/handle/123456789/33428. Acesso em: $DATA.

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Abstract: The Helium-3 shortage and the growing interest in neutron science constitute a driving factor in developing new neutron detection technologies. In this work, we report the development of a double-GEM detector prototype that uses a 10B4C layer as a neutron converter material. GEANT4 simulations were performed predicting an efficiency of (3.14 ± 0.10)%, agreeing within 2.7σ with the experimental and analytic detection efficiencies obtained by the detector when tested in a 41.8 meV thermal neutron beam. The detector is position sensitive, equipped with a 256+256 strip readout connected to resistive chains, and achieves a spatial resolution better than 3 mm. The gain stability over time was also measured with a fluctuation of about 0.2% h-1 of the signal amplitude. A simple data acquisition with only 5 electronic channels is sufficient to operate this detector.

Palavras-Chave: neutron detectors; fast neutrons; gas track detectors; thermal neutrons

SERRA FILHO, L.A.; FELIX DOS SANTOS, R.; SOUZA, G.G.A. de; PAULINO, M.M.M.; SOUZA, F.A.; MORALLES, M.; LUZ, H.N. da; BREGANT, M.; MUNHOZ, M.G.; LAI, C.-C.; HOGLUND, C.; SVENSSON, P.-O.; ROBINSON, L.; HALL-WILTON, R. Double-GEM based thermal neutron detector prototype. Journal of Instrumentation, v. 17, n. 9, p. 1-15, 2022. DOI: 10.1088/1748-0221/17/09/P09018. Disponível em: http://repositorio.ipen.br/handle/123456789/33426. Acesso em: $DATA.

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Abstract: The challenges for developing new pharmaceutical formulations based on natural and synthetic polymers has led to innovation into the design of systems responsive environmental stimuli such as temperature. However, the presence of hydrophilic or hydrophobic molecules, charged groups, or metallic elements can affect their structural behavior and their biopharmaceutical performance This work aims to study and characterize the morphology and structure of polymeric formulations based on Poloxamer (PL) 407 (15 % and 30 % m/v) and its binary with PL 338 (15 % PL 407 + 15 % PL 338) and hyaluronic acid (0.5 % m/v), as drug delivery systems of local anesthetic bupivacaine (0.5 % m/v) and ropivacaine (0.5 % m/v) hydrochloride. For this, it was performed SANS analysis for determination of supramolecular organization and lattice parameters; calorimetry was done to characterize their thermodynamic parameters; rheological analysis flow curve, consistency and adhesion calculation, Maxwell model study. Also, it was performed drug release profiles and calculation of diffusion coefficients. It was identified lamellar structures in PL 407 15 % formulations, and coexistence of cubic and hexagonal phases in PL 407 30 % and binary formulations, however hyaluronic acid, bupivacaine or ropivacaine seem do not affect the type of supramolecular structure. In addition, these additives can modulate viscosity among poloxamers chains, increasing micelle-micelle interactions as it happens in presence of bupivacaine. On the other hand, addition of hyaluronic acid can promote increased structural stabilization by hydrophilic interactions between hyaluronic and micellar corona. It reflects the ability how to control the drug release, as in case of binary system that retained bupivacaine for longer time than other systems, as well it happens when hyaluronic acid is added in PL 407 15 % and PL 407 30 %.

Palavras-Chave: copolymers; hydrogels; drug delivery

SEPULVEDA, ANDERSON F.; KUMPGDEE-VOLLRATH, MONT; FRANCO, MARGARETH K.K.D.; YOKAICHIYA, FABIANO; ARAUJO, DANIELE R. de. Supramolecular structure organization and rheological properties modulate the performance of hyaluronic acid-loaded thermosensitive hydrogels as drug-delivery systems. Journal of Colloid and Interface Science, v. 630, n. Part B, p. 328-340, 2023. DOI: 10.1016/j.jcis.2022.10.064. Disponível em: http://repositorio.ipen.br/handle/123456789/33424. Acesso em: $DATA.

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Abstract: This study presents the deduction of time domain mathematical equations to simulate the curve of the charging process of a symmetrical electrochemical supercapacitor with activated carbon electrodes fed by a source of constant electric potential in time ε and the curve of the discharge process through two fixed resistors. The first resistor RCo is a control that aims to prevent sudden variations in the intensity of the electric current i1(t) present at the terminals of the electrochemical supercapacitor at the beginning of the charging process. The second resistor is the internal resistance RA of the ammeter used in the calculation of the intensity of the electric current i1(t) over time in the charging and discharging processes. The mathematical equations generated were based on a 2R(C + kUC(t)) electrical circuit model and allowed to simulate the effects of the potential-dependent capacitance (kUC(t)) on the charge and discharge curves and hence on the calculated values of the fixed capacitance C, the equivalent series resistance (ESR), the equivalent parallel resistance (EPR) and the electrical potential dependent capacitance index k.

Palavras-Chave: capacitors; electronic circuits; mathematical solutions; equations; simulation; electric potential; capacitance

FERNANDEZ, ANTONIO P.R.; PERIGO, ELIO A.; FARIA JUNIOR, RUBENS N. de. Modeling and simulations in symmetrical supercapacitors using time domain mathematical expressions. Journal of Applied Mathematics and Physics, v. 10, n. 10, p. 3083-3100, 2022. DOI: 10.4236/jamp.2022.1010206. Disponível em: http://repositorio.ipen.br/handle/123456789/33422. Acesso em: $DATA.

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Abstract: New materials are being studied and widely applied in the health area, highlighting biocompatible polymers as the most versatile. Among these polymers, we developed the methodology for the manufacture of Thermoplastic Polyurethane films for application as Biomaterials. The proposed sterilization by ionizing radiation requires the study and characterization of the material to evaluate possible losses or modifications, due to the influence that the radiation can cause in the polymer chains, losing the characteristics for the purpose used. Therefore, the present work evaluates, through chemical and physical-chemical characterization, the possible extension of the changes caused by the radiation in the polyurethane film. The material is produced in an environment with controlled temperature and humidity and subjected to increasing doses of gamma (15, 25 and 50 kGy), ethylene oxide and plasma as comparative techniques. The techniques DSC (Differential Scanning Calorimetry), TGA (Thermogravimetry), FTIR-ATR (Fourier Transform Infrared Spectrometry), SEM (Scanning electron microscopy) and OCT (Optical coherence tomography), have proved that the material, after applied the sterilization techniques, maintains its physical-chemical characteristics and does not suffer any modifications after the treatment.

Palavras-Chave: polyurethanes; thermoplastics; polymers; surgical materials; prostheses

MASSEI, MARIANA G.R.; MATOS, JIVALDO R.; MACHADO, LUCI D.B.; MALUF, MIGUEL A.; MATHOR, MONICA B. Study of the interaction of ionizing radiation in polyrethane polymer films as biomaterial. International Journal of Advances in Medical Biotechnology, v. 4, n. 2, p. 46-53, 2021. DOI: 10.52466/ijamb.v4i1.97. Disponível em: http://repositorio.ipen.br/handle/123456789/33420. Acesso em: $DATA.

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Abstract: Bladder cancer (BC) is the tenth most common type of cancer worldwide, affecting up to four times more men than women. Depending on the stage of the tumor, different therapy protocols are applied. Non-muscle-invasive cancer englobes around 70% of the cases and is usually treated using the transurethral resection of bladder tumor (TURBIT) followed by the instillation of chemotherapy or immunotherapy. However, due to bladder anatomy and physiology, current intravesical therapies present limitations concerning permeation and time of residence. Furthermore, they require several frequent catheter insertions with a reduced interval between doses, which is highly demotivating for the patient. This scenario has encouraged several pieces of research focusing on the development of drug delivery systems (DDS) to improve drug time residence, permeation capacity, and target release. In this review, the current situation of BC is described concerning the disease and available treatments, followed by a report on the main DDS developed in the past few years, focusing on those based on mucoadhesive polymers as a strategy. A brief review of methods to evaluate mucoadhesion properties is also presented; lastly, different polymers suitable for this application are discussed.

Palavras-Chave: adhesion; drug delivery; bladder; neoplasms; hydrogels; polymers; therapy

LIMA, CAROLINE S.A. de; VARCA, JUSTINE P.R.O.; ALVES, VICTORIA M.; NOGUEIRA, KAMILA M.; CRUZ, CASSIA P.C.; RIAL-HERMIDA, M. ISABEL; KADLUBOWSKI, SLAWOMIR S.; VARCA, GUSTAVO H.C.; LUGAO, ADEMAR B. Mucoadhesive polymers and their applications in drug delivery systems for the treatment of bladder cancer. Gels, v. 8, n. 9, p. 1-25, 2022. DOI: 10.3390/gels8090587. Disponível em: http://repositorio.ipen.br/handle/123456789/33418. Acesso em: $DATA.

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Abstract: Regulation of inflammation is a critical process for maintaining physiological homeostasis. The λ-carrageenan (λ-CGN) is a mucopolysaccharide extracted from the cell wall of red algae (Chondrus crispus) capable of inducing acute intestinal inflammation, which is translated into the production of acute phase reactants secreted into the blood circulation. However, the associated mechanisms in vertebrates are not well understood. Here, we investigated the crucial factors behind the inflammatory milieu of λ-CGN-mediated inflammation administered at 0, 1.75, and 3.5% (v/w) by i.p. injection into the peritoneal cavity of adult zebrafish (ZF) (Danio rerio). We found that polymorphonuclear leukocytes (neutrophils) and lymphocytes infiltrating the ZF peritoneal cavity had short-term persistence. Nevertheless, they generate a strong pattern of inflammation that affects systemically and is enough to produce edema in the cavity. Consistent with these findings, cell infiltration, which causes notable tissue changes, resulted in the overexpression of several acute inflammatory markers at the protein level. Using reversed-phase high-performance liquid chromatography followed by a hybrid linear ion-trap mass spectrometry shotgun proteomic approach, we identified 2938 plasma proteins among the animals injected with PBS and 3.5% λ-CGN. First, the bioinformatic analysis revealed the composition of the plasma proteome. Interestingly, 72 commonly expressed proteins were recorded among the treated and control groups, but, surprisingly, 2830 novel proteins were differentially expressed exclusively in the λ-CGN-induced group. Furthermore, from the commonly expressed proteins, compared to the control group 62 proteins got a significant (p < 0.05) upregulation in the λ-CGN-treated group, while the remaining ten proteins were downregulated. Next, we obtained the major protein-protein interaction networks between hub protein clusters in the blood plasma of the λ-CGN induced group. Moreover, to understand the molecular underpinnings of these effects based on the unveiled protein sets, we performed a bioinformatic structural similarity analysis and generated overlapping 3D reconstructions between ZF and humans during acute inflammation. Biological pathway analysis pointed to the activation and abundance of diverse classical immune and acute phase reactants, several catalytic enzymes, and varied proteins supporting the immune response. Together, this information can be used for testing and finding novel pharmacological targets to treat human intestinal inflammatory diseases.

Palavras-Chave: glycoproteins; immunity; fishes; proteins

CHARLIE-SILVA, IVES; FEITOSA, NATALIA M.; PONTES, LETICIA G.; FERNANDES, BIANCA H.; NOBREGA, RAFAEL H.; GOMES, JULIANA M.M.; PRATA, MARIANA N.L.; FERRARIS, FAUSTO K.; MELO, DANIELA C.; CONDE, GABRIEL; RODRIGUES, LETICIA F.; ARACATI, MAYUMI F.; CORREA-JUNIOR, JOSE D.; MANRIQUE, WILSON G.; SUPERIO, JOSHUA; GARCEZ, AGUINALDO S.; CONCEICAO, KATIA; YOSHIMURA, TANIA M.; NUNEZ, SILVIA C.; ETO, SILAS F.; FERNANDES, DAYANNE C.; FREITAS, ANDERSON Z.; RIBEIRO, MARTHA S.; NEDOLUZHKO, ARTEM; LOPES-FERREIRA, MONICA; BORRA, RICARDO C.; BARCELLOS, LEONARDO J.G.; PEREZ, ANDREA C.; MALAFAIA, GUILHEME; CUNHA, THIAGO M.; BELO, MARCO A.A.; GALINDO-VILLEGAS, JORGE. Plasma proteome responses in zebrafish following λ-carrageenan-Induced inflammation are mediated by PMN leukocytes and correlate highly with their human counterparts. Frontiers in Immunology, v. 13, p. 1-21, 2022. DOI: 10.3389/fimmu.2022.1019201. Disponível em: http://repositorio.ipen.br/handle/123456789/33416. Acesso em: $DATA.

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Abstract: Biosorption has been examined for the treatment of aqueous solutions containing uranium, a radiotoxic pollutant. Nevertheless, the evaluation of the role of process variables by experimental design on the use of hydroxyapatite and bone meal as biosorbents for uranium has not yet been previously addressed. In this study, the effects of adsorbent dosage (M), initial uranium concentrations ([U]0), and solution pH were investigated, using a two-level factorial design and response surface analysis. The experiments were performed in batch, with [U]0 of 100 and 500 mg L−1, pH 3 and 5, and adsorbent/uranium solution ratios of 5 and 15 g L−1. Contact time was fixed at 24 h. Removal rates were higher than 88%, with a maximum of 99% in optimized conditions. [U]0 and M were found to be the most influential variables in U removal in terms of adsorption capacity (q). The experiments revealed that bone meal holds higher adsorption capacity (49.87 mg g−1) and achieved the highest uranium removal (~ 100%) when compared to hydroxyapatite (q = 49.20 mg g−1, removal = 98.5%). The highest value of q for both biomaterials was obtained for [U]0 = 500 mg L−1, pH 3, and M = 5 g L−1. Concerning the removal percentage, bone meal achieved the best performance for [U]0 = 500 mg L−1, pH 3, and M = 15 g L−1. Further experiments were made with real radioactive waste, resulting in a high uranium adsorption capacity for both materials, with 22.11 mg g−1 for hydroxyapatite and 22.08 mg g−1 for bone meal, achieving uranium removal efficiencies higher than 99%.

Palavras-Chave: adsorption; radioisotopes; radioactive wastes; surface; skeleton

WATANABE, TAMIRES; GUILHEN, SABINE N.; MARUMO, JULIO T.; SOUZA, RODRIGO P. de; ARAUJO, LEANDRO G. de. Uranium biosorption by hydroxyapatite and bone meal: evaluation of process variables through experimental design. Environmental Science and Pollution Research, v. 29, n. 53, p. 79816-79829, 2022. DOI: 10.1007/s11356-021-17551-x. Disponível em: http://repositorio.ipen.br/handle/123456789/33414. Acesso em: $DATA.

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Abstract: The development of heterogeneous electrochemical activity in the welded zones of aluminum alloy 2098-T351 by friction stir welding (FSW) associated with the formation of a near-surface deformed layer (NSDL) upon exposure to an aqueous chloride-containing solution was characterized using scanning electrochemical microscopy (SECM) in potentiometric operation. A solid-contact Mg2+ ion-selective microelectrode allowed in situ monitoring of the corrosion reactions sites for magnesium dissolution from different zones of the FSW weld upon exposure to a chloride-containing aqueous environment. In this way, localized corrosion reactions developing in the galvanically coupled joint/heat affected zones (WJ/HAZ) of the weld were detected and imaged with spatial resolution. The most active domains for local Mg2+ concentrations were associated with the HAZ of the retreating side (RS), and these corresponded to Mg oxidation from the Mg-enriched oxide bands in NSDL.

Palavras-Chave: aluminium alloys; friction welding; layers; magnesium ions; electrodes

SILVA, REJANE M.P. da; IZQUIERDO, JAVIER; MILAGRE, MARIANA X.; ARAUJO, JOAO V. de S.; ANTUNES, RENATO A.; SOUTO, RICARDO M.; COSTA, ISOLDA. Electrochemical characterization of alloy segregation in the near-surface deformed layer of welded zones of an Al-Cu-Li alloy using scanning electrochemical microscopy. Electrochimica Acta, v. 427, p. 1-7, 2022. DOI: 10.1016/j.electacta.2022.140873. Disponível em: http://repositorio.ipen.br/handle/123456789/33412. Acesso em: $DATA.

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Abstract: Background: 2-[18F]Fluoroethyltosylate ([18F]FEtOTs) is a well-known 18F-fluoroalkylating agent widely used to synthesize radiotracers for positron emission tomography. The widespread use of [18F]FEtOTs is due in part to its low volatility when compared to other halide and sulfonate building blocks. In this work, the radioactive volatile side-products formed during the synthesis of [18F]FEtOTs were identified and characterized for the first time, and an optimization of the reaction conditions to minimize their formation was proposed. Results: In order to characterize the volatiles produced during [18F]FEtOTs synthesis, the reaction mixtures of both cold FEtOTs and [18F]FEtOTs were co-injected onto the HPLC system. The radioactive peaks corresponding to the volatile compounds were collected, analyzed through headspace gas chromatography mass spectrometry sampler (HS-GC–MS) and identified as vinyl fluoride ([19F]VF) and 2-fluoroethanol ([19F]FEOH). By using a rotatable central composite design with a two-level full factorial core of two factors (22), it was determined that temperature and time are independent variables which affect the generation of [18F]VF and [18F]FEOH during the radiosynthesis of [18F]FEtOTs. In addition, in order to reduce the formation of the volatiles ([18F]VF and [18F]FEOH) and increase the yield of [18F]FEtOTs, it was demonstrated that the molar ratio of base to precursor must also be considered. Conclusion: [18F]VF and [18F]FEOH are volatile side-products formed during the radiosynthesis of [18F]FEtOTs, whose yields depend on the reaction time, temperature, and the molar ratio of base to precursor. Therefore, special care should be taken during the radiosynthesis and subsequent reactions using [18F]FEOTs in order to avoid environmental contamination and to improve the yield of the desired products.

Palavras-Chave: fluorides; fluorine 18; gases; radioactive materials; radiation protection; positron computed tomography

PIJEIRA, MARTHA S.O.; SANTOS, SOFIA N. dos; ARAUJO, YASNIEL B.; LAPOLLI, ANDRE L.; WANDERMUREN, MARCIO N.; RIERA, ZALUA R.; CARVALHO, IVONE; ELSINGA, PHILIP H.; BERNARDES, EMERSON S. A closer look at the synthesis of 2‑[18F] fluoroethyl tosylate to minimize the formation of volatile side‑products. EJNMMI Radiopharmacy and Chemistry, v. 7, n. 1, p. 1-15, 2022. DOI: 10.1186/s41181-022-00179-8. Disponível em: http://repositorio.ipen.br/handle/123456789/33410. Acesso em: $DATA.

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Abstract: Low-level jets are a recurrent feature of our study area in Ipero municipality of southeastern Brazil. They grow very near the surface as shown by this case study. These two aspects increase the needs for a realistic modeling of the low-level jet to simulate the atmospheric dispersion of industrial emissions. In this concern, we applied a recently proposed technique to estimate the turbulence kinetic energy dissipation rate of a low-level jet case with Doppler lidar data. This low-level jet remained for its entire lifetime (around 12 h) within a shallow layer (under 300 m); beyond this, we did not notice a remarkable directional shear as in other studies. Even for a shallow layer as for this study case, we observed strong spatiotemporal variability of the turbulence kinetic energy dissipation rate. We also detected a channel connecting the layers above and below the low-level jet that may be an exchange channel of their properties.

Palavras-Chave: optical radar; turbulence; transverse energy; atmospheric circulation; boundary layers; jets

BEU, CASSIA M.L.; LANDULFO, EDUARDO. Turbulence kinetic energy dissipation rate estimate for a low-level jet with Doppler lidar data: a case study. Earth Interactions, v. 26, n. 1, p. 112-121, 2022. DOI: 10.1175/EI-D-20-0027.1. Disponível em: http://repositorio.ipen.br/handle/123456789/33406. Acesso em: $DATA.

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Abstract: This study investigates the electrochemical impedance diagrams obtained for a Mg electrode in a sodium sulphate solution at different pHs. A comprehensive model, independent of the pH range, with the presence of two adsorbed intermediates accounting for the anodic dissolution and the cathodic reaction was proposed to explain the singular behaviour of Mg at low pH values. It was also shown that, in acidic media, the contribution of the double layer as well as the cathodic partial reaction must be considered, whereas at higher pH values the oxide/hydroxide layer plays a significant role and slows down the magnesium corrosion rate.

Palavras-Chave: magnesium; impedance; corrosion; adsorbents

BENBOUZID, ABDELMOHEIMAN Z.; GOMES, MAURILIO P.; COSTA, ISOLDA; GHARBI, OUMAIMA; PEBERE, NADINE; ROSSI, JESUALDO L.; TRAN, MAI T.T.; TRIBOLLET, BERNARD; TURMINE, MIREILLE; VIVIER, VINCENT. A new look on the corrosion mechanism of magnesium: an EIS investigation at different pH. Corrosion Science, v. 205, p. 1-12, 2022. DOI: 10.1016/j.corsci.2022.110463. Disponível em: http://repositorio.ipen.br/handle/123456789/33402. Acesso em: $DATA.

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Abstract: Pelletization of zeolitic materials is required to facilitate their practical industrial and commercial applications. Zeolite-NaA was synthesized from fly ash by the fusion method and shaped into spherical granules. Bentonite, kaolinite, and a combination of bentonite with kaolinite were tested as binders with different contents from 5 to 10 wt%. The pellet formation was optimized. The physicochemical properties of binders, zeolite powder, and zeolite granular were characterized by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption/desorption isotherm, and scanning electron microscopy (SEM) among other techniques. Deformation and breakage behavior of spherical granulates by compression was also studied. The best performance was obtained by the pellet with 10% bentonite with satisfactory mechanical strength and water resistance. The XRD and SEM results revealed NaA zeolite granular with a typical cubic shape and high crystallinity formed on the surface of bentonite. This result presents a potential use of the coal fly ash to obtain pelletized NaA zeolite following the principles of circular economy and the sustainable development goals (SDGs), particularly SDG 12.

Palavras-Chave: ashes; bentonite; binders; coal; fourier transformation; infrared spectra; kaolinite; pelletizing; thermal gravimetric analysis; zeolites

BERTOLINI, T.C.R.; FUNGARO, D.A.; MAHMOUD, A.E.D. The influence of separately and combined bentonite and kaolinite as binders for pelletization of NaA zeolite from coal fly ash. Cerâmica, v. 68, n. 387, p. 375-384, 2022. DOI: 10.1590/0366-69132022683873322. Disponível em: http://repositorio.ipen.br/handle/123456789/33396. Acesso em: $DATA.

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Abstract: Dosimetric evaluation is indicated for material characterization seeking to identify possible applications; still, proper preprocessing techniques are critical features of this process. This work aimed to determine the linearity response of plastic samples irradiated with gamma rays using the Fourier Transform Infrared (FTIR) measurements. The plastic samples were analyzed using Derivatives and Principal Component Analysis (PCA) methods. They applied linear and Principal Component Regression (PCR) methods to obtain linearity. The methods obtained good results for linearity and also showed the evolution of each technique. In conclusion, the results indicate that the applied methods can be useful in radiation physics and for plastic samples as interesting potential radiation detectors.

Palavras-Chave: absorbed radiation doses; cobalt 60; dosemeters; dosimetry; fourier transformation; gamma radiation; polyethylene terephthalate; principal component analysis; radiation detectors

OLIVEIRA, L.N.; NASCIMENTO, E.O.; ANTONIO, P.L.; CALDAS, L.V.E. Plastic bottle caps as radiation detectors for high gamma radiation doses. Brazilian Journal of Radiation Sciences, v. 10, n. 2A, p. 1-18, 2022. DOI: 10.15392/bjrs.v10i2A.1761. Disponível em: http://repositorio.ipen.br/handle/123456789/33384. Acesso em: $DATA.

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Abstract: Ethylene-vinyl acetate (EVA) is the flexible plastic material commonly used in industries. The EVA samples, in green, white and black colors were irradiated with absorbed doses of 0.01 kGy up to 10.0 kGy using a 60Co Gamma Cell-220 system, and the Fourier Transform Infrared (FTIR) spectrophotometry technique was used for evaluating the samples. This work aimed to investigate EVA samples in measurements with gamma radiation, analyzing the linearity through the Principal Component Regression (PCR) method and its sensitivity. For sensitivity and linearity, the green samples showed the best results, followed by white and black EVA samples. The PCR method inflated gradually the number of principal components, then reducing the residuals between the measured and calculated values, consequently obtaining maximum linearity of 1.000 for all of the EVA samples. In conclusion, the FTIR was adequate for the acquisition of absorbance spectra; the linearity via PCR and sensitivity showed good results indicating that the EVA detectors can be useful in radiation measurements.

Palavras-Chave: absorbed radiation doses; cobalt 60; dosemeters; dosimetry; ethylene; fourier transformation; regression analysis; sensitivity; vinyl acetate

OLIVEIRA, L.N.; NASCIMENTO, E.O.; ANTONIO, P.L.; CALDAS, L.V.E. Ethylene-vinyl acetate detector exposed to gamma radiation and evaluated via principal component regression. Brazilian Journal of Radiation Sciences, v. 10, n. 2A, p. 1-17, 2022. DOI: 10.15392/bjrs.v10i2A.1760. Disponível em: http://repositorio.ipen.br/handle/123456789/33382. Acesso em: $DATA.

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Abstract: The gas Centrifuge is a very hard equipment to model, because it involves a gas dynamic with many complications, such as hypersonic waves and rarefied regions combined with continuous flow areas. Therefore, data analysis regressions remain currently a very important technique to understand and describe the problem in a practical way. This paper intends to apply and compare several regression techniques using machine learning, to obtain a hydraulic and a separative power model of gas centrifuge used in enrichment plants. For this purpose, a set of normalized data composed of 134 experimental lines was used, observing the variables of interest, the separation power (dU), and the waste pressure (Pw), through the following explanatory variables: feed flow (F), cut (q), and product pressure (Pp). The comparisons were presented between the results obtained for the models generated by the following: algorithms, multivariate regression, multivariate adaptive regression splines – MARS, bootstrap aggregating multivariate adaptive regression splines – Bagging MARS, artificial neural network – ANN, extreme gradient boosting – XGBoost, support vector regression– Poly SVR, radial basis Function support vector regression – RBF SVR, K-nearest neighbors – KNN and Stacked Ensemble. That way, to avoid overfitting and provide insights about generalization of the models in unseen data, during the training phase, the k-fold cross validation approach was used. Subsequently, the residuals were analyzed, and the models were compared by the following metrics: Root mean square error – RMSE; Mean squared error – MSE; Mean absolute error – MAE; and Coefficient of determination – R2.

Palavras-Chave: isotope separation; gas centrifuges; machine learning; multivariate analysis; neural networks; algorithms; automation

ANDRADE, DELVONEI A. de; MESQUITA, ROBERTO N. de; NASCIMENTO, NATAN P. A comparative study on machine learning regression algorithms aplied to modeling gas centrifuge. Brazilian Journal of Development, v. 8, n. 7, p. 52669-52681, 2022. DOI: 10.34117/bjdv8n7-265. Disponível em: http://repositorio.ipen.br/handle/123456789/33380. Acesso em: $DATA.

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Abstract: Super-magnets, materials whose strong magnetic activity is an attractive differential for the hightech industry, may have their magnetic performance affected by small variations in their chemical composition. For example, the neodymium and praseodymium content can change the physicochemical properties of the permanent magnets. Aiming at a strict chemical quality control, this work developed an analytical method to quantify the major elements in the materials involved in the production process of didymium (the mixture of neodymium and praseodymium) super-magnets. The simultaneous determination of Nd (401.225 nm), Pr (414.311 nm), Fe (259.837 nm) and B (249.678 nm) in three different sample types (didymium oxide, metallic didymium and (Nd,Pr)-Fe-B alloy) was performed by sample dissolution in acidic media, followed by instrumental measurements using an Inductively Coupled Plasma Optical Emission Spectrometer. Linear calibration curves were obtained with high coefficient of determination (0.9983 ≤ R2 ≤ 0.9999) and with appropriate limits for determining these elements at the percentage level, reaching detection limits less than 0.07 cg g-1. The precision of the method was improved by weighing of the solutions during all the dilution steps and was evaluated by the coefficient of variation associated to instrumental precision (0.3 – 0.7%), method intermediate precision (1.9 – 3.1%) and also by the typical mass fraction provided as uncertainty (0.04 – 0.20 cg g-1), reaching the pressing need to distinguish the content of the rare earth elements in less than 1 cg g-1. The accuracy of the method was assessed by spiked and recovery test (96-104% for spikes equal to or greater than 0.50 cg g-1) and also by the use of different analytical methods, involving the participation of other laboratories, obtaining an acceptable degree of agreement (85 – 107%).

Palavras-Chave: emission spectroscopy; metals; alloys; magnetic properties; neodymium

PAPAI, RODRIGO; FONSECA, KARINA T. da; ALMEIDA, GILMAR A. de; SILVA, ANDRE L.N. da; NAGASIMA, THIAGO P.; JABES, EDUARDO G.; SANTOS, CELIA A.L. dos; LANDGRAF, FERNANDO J.G.; LUZ, MACIEL S. Chemical characterization in the production chain of permanent magnets by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES): precise quantification of Nd, Pr, Fe and B in super-magnets samples. Brazilian Journal of Analytical Chemistry, v. 9, n. 36, p. 124-145, 2022. DOI: 10.30744/brjac.2179-3425.TN-108-2021. Disponível em: http://repositorio.ipen.br/handle/123456789/33378. Acesso em: $DATA.

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Abstract: Objectives The study investigated the long-term functional status of hospitalised COVID-19 survivors to explore and document their functional situation. Design This prospective observational study assessed 801 COVID-19 survivors at 3–11 months after hospital discharge. It analyses participants' sociodemographic background, COVID-19 clinical manifestations, and clinical and functional evaluations. Setting Tertiary-level university hospital in São Paulo, Brazil. Participants Study participants are COVID-19 survivors admitted to hospital care for at least 24 hours to treat acute SARS-CoV-2 infection. Outcome measures Epworth Sleepiness Scale, EuroQoL-5 Dimensions-5 Levels, Functional Assessment of Chronic Illness Therapy–Fatigue, Functional Independence Measure, Functional Oral Intake Scale, Handgrip Strength, Insomnia Severity Index, Medical Research Council (MRC) Dyspnea Scale, MRC sum score, Modified Borg Dyspnea Scale, pain Visual Analogue Scale, Post-COVID-19 Functional Status, Timed Up and Go, WHO Disability Assessment Schedule 2.0, 1-Minute Sit to Stand Test. Results Many participants required invasive mechanical ventilation (41.57%, 333 of 801). Mean age was 55.35±14.58 years. With a mean of 6.56 (SD: 1.58; 95% CI: 6.45 to 6.67) months after hospital discharge, 70.86% (567 of 800) reported limited daily activities, which were severe in 5.62% (45 of 800). They also reported pain and discomfort (64.50%, 516 of 800), breathlessness (64.66%, 514 of 795), and anxiety and depression (57.27%, 457 of 798). Daytime sleepiness and insomnia evaluations showed subthreshold results. Most (92.85%, 727 of 783) participants reported unrestricted oral intake. Data indicated no generalised fatigue (mean score: 39.18, SD: 9.77; 95% CI: 38.50 to 39.86). Assessments showed poor handgrip strength (52.20%, 379 of 726) and abnormal Timed Up and Go results (mean 13.07 s, SD: 6.49). The invasive mechanical ventilation group seemed to have a better handgrip strength however. We found no clear trends of change in their functional status during months passed since hospital discharge. Conclusions Muscle weakness, pain, anxiety, depression, breathlessness, reduced mobility, insomnia and daytime sleepiness were the most prevalent long-term conditions identified among previously hospitalised COVID-19 survivors.

Palavras-Chave: coronaviruses; patients; health services; hospitals; human populations; disease incidence; oxygen

BATTISTELLA, LINAMARA R.; IMAMURA, MARTA; DE PRETTO, LUCAS R.; VAN CAUWENBERGH, SIMON K.H.A.A.; RAMOS, VINICIUS D.; UCHIYAMA, SABRINA S.T.; MATHEUS, DENISE; KUHN, FLAVIA; OLIVEIRA, ANA A.A. de; NAVES, GABRIELLA S.; MIRISOLA, ALINE R.; RIBEIRO, FERNANDO de Q.; SUGAWARA, ANDRE T.; CANTARINO, MAURICIO; CAVALCA, RAFAEL A.S.A.; PAGANO, VANESSA; MARQUES, MELINA V.; SILVA, ELIZABETH M. da; GOMES, ALESSANDRA P.; FREGNI, FELIPE. Long-term functioning status of COVID-19 survivors: a prospective observational evaluation of a cohort of patients surviving hospitalisation. BMJ Open, v. 12, n. 7, p. 1-11, 2022. DOI: 10.1136/bmjopen-2021-057246. Disponível em: http://repositorio.ipen.br/handle/123456789/33376. Acesso em: $DATA.

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Abstract: This paper described an impedimetric immunosensor for detecting Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Antibodies from egg yolk (Ab-PfHRP2, IgY type) were linked covalently to the screen-printed gold electrodes (SPGE) surface modified with a thin film of Poly-pyrrole-pyrrole 3 carboxylic acid (P(Py-Py3COOH) to develop the sensing platform. The fabrication steps were followed by microscopic (scanning electron microscopy), spectroscopic (RAMAN spectroscopy and Energy-dispersive X-ray spectroscopy), and electrochemical (electrochemical impedance spectroscopy (EIS) and cyclic voltammetry) techniques. The determination of Ag-PfHRP2 was performed by EIS, and the BSA(bovine serum albumin)/Ab-PfHRP2(IgY)/P(Py-Py3COOH)/SPGE immunosensor recorded a linear response at 100–1000 ng mL−1 concentration range, with a limit of detection (LOD) of 27.47 ng mL−1. Its performance was confirmed by Enzyme-Linked Immuno-Sorbent Assay. The fabricated device uses a simple strategy of IgY immobilization, showing high sensitivity and good selectivity, and can be considered an alternative for carrying out malaria tests.

Palavras-Chave: malaria; antibodies; immunoglobulins; plasmodium; immunoassay; detection; electrodes

GANDARILLA, ARIAMNA M.D.; GLORIA, JULIANE C.; BARCELAY, YONNY R.; SOUZA, RODRIGO F.B. de; MARIUBA, LUIS A.M.; BRITO, WALTER R. Application of egg yolk IgY on carboxylated polypyrrole films for impedimetric detection of PfHRP2 antigen. Bioelectrochemistry, v. 148, p. 1-8, 2022. DOI: 10.1016/j.bioelechem.2022.108273. Disponível em: http://repositorio.ipen.br/handle/123456789/33374. Acesso em: $DATA.

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Abstract: Identifying the origin of NOx emissions, their transformation into nitrate (NO3−) and its atmospheric deposition is important to better understand the impacts of air pollution on the environment and human health, on a local and regional scale. We measured nitrate isotopes (δ15N, δ18O of NO3−) in precipitation samples in a tropical station in Brazil in 2019–2020 and combined them with chemical, geospatial and meteorological data to trace NOx sources towards their wet deposition as NO3−. A total wet N deposition of ∼12 kg N/ha.year showed significant N air pollution, out of which the relative contribution of NO3−-N was ∼37% (4.6 kg NO3−-N/ha.year). The δ15N–NO3- values in precipitation ranged from −8.5 to +4.1‰, with a volume-weighted mean (VWM) value of −3.0 ± 2.7‰, whereas the δ18O–NO3- values ranged from +25.9 to +63.5‰ with a VWM value of +53.3 ± 7.3‰. The δ15N–NO3- results combined with air mass backward trajectory analysis and geospatial mapping revealed that the NOx emissions in Belo Horizonte originated from: vehicles and industries from the urban and industrialized areas, biomass burning related to wildfires, and ship emissions from the coastal areas. The temporal variation of δ15N, δ18O of NO3− values was attributed to NOx source variability and transformation processes. The use of integrated methods to evaluate the imprints of anthropogenic air pollution sources in Brazil will contribute to inform NOx source management strategies and improve air and water quality.

Palavras-Chave: stable isotopes; washout; nitrogen oxides; geographic information systems; air pollution; pollution sources

PASSOS, RICARDO G.; MATIATOS, IOANNIS; MONTEIRO, LUCILENA R.; ALMEIDA, RAFAEL S.S.P.; LOPES, NILVA P.; CARVALHO FILHO, CARLOS A.; COTA, STELA D.S. Imprints of anthropogenic air pollution sources on nitrate isotopes in precipitation in a tropical metropolitan area. Atmospheric Environment, v. 288, p. 1-14, 2022. DOI: 10.1016/j.atmosenv.2022.119300. Disponível em: http://repositorio.ipen.br/handle/123456789/33372. Acesso em: $DATA.

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Abstract: The aerosol radiative effect is an important source of uncertainty in estimating the anthropogenic impact of global climate change. One of the main open questions is the role of radiation absorption by aerosols and its relation to land use worldwide, particularly in the Amazon Rainforest. Using AERONET (Aerosol Robotic Network) long-term measurements of aerosol optical depth (AOD) at a wavelength of 500 nm and absorption AOD (AAOD) at wavelengths of 440, 675, and 870 nm, we estimated the fraction and seasonality of the black carbon (BC) and brown carbon (BrC) contributions to absorption at 440 nm. This was conducted at six Amazonian sites, from central Amazon (Manaus and the Amazon Tall Tower Observatory—ATTO) to the deforestation arc (Rio Branco, Cuiabá, Ji-Paraná, and Alta Floresta). In addition, land use and cover data from the MapBiomas collection 6.0 was used to access the land transformation from forest to agricultural areas on each site. The results showed, for the first time, important geographical and seasonal variability in the aerosol optical properties, particularly the BC and BrC contributions. We observed a clear separation between dry and wet seasons, with BrC consistently accounting for an average of approximately 12% of the aerosol AAOD at 440 nm in the deforestation arc. In central Amazon, the contribution of BrC was approximately 25%. A direct relationship between the reduction in forests and the increase in the area dedicated to agriculture was detected. Moreover, places with lower fractions of forest had a smaller fraction of BrC, and regions with higher fractions of agricultural areas presented higher fractions of BC. Therefore, significant changes in AOD and AAOD are likely related to land-use transformations and biomass burning emissions, mainly during the dry season. The effects of land use change could introduce differences in the radiative balance in the different Amazonian regions. The analyses presented in this study allow a better understanding of the role of aerosol emissions from the Amazon Rainforest that could have global impacts.

Palavras-Chave: aerosol monitoring; remote sensing; carbon; land use; amazon river

MORAIS, FERNANDO G.; FRANCO, MARCO A.; PALACIOS, RAFAEL; MACHADO, LUIZ A.T.; RIZZO, LUCIANA V.; BARBOSA, HENRIQUE M.J.; JORGE, FABIO; SCHAFER, JOEL S.; HOLBEN, BRENT N.; LANDULFO, EDUARDO; ARTAXO, PAULO. Relationship between land use and spatial variability of atmospheric brown carbon and black carbon aerosols in Amazonia. Atmosphere, v. 13, n. 8, p. 1-17, 2022. DOI: 10.3390/atmos13081328. Disponível em: http://repositorio.ipen.br/handle/123456789/33368. Acesso em: $DATA.

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Abstract: Colloids composed of metallic nanoparticles are promising working fluids for solar radiation harvesting using Direct Absorption Solar Collectors (DASC), due to a high thermal conductivity characteristic and a broad optical absorption that can be tuned to match the solar spectrum. Recently, different studies report gold nanorod (Au-NR) chains for biosensing and photothermal applications, which have broadband and high absorption cross-section and potential possibilities to orientate the nanoparticle using electromagnetic fields. Moreover, colloids with nanoparticles blended configuration show an efficient solar radiation absorption characteristics. Here, working fluids for DASC based on gold nanorod chains in an unblended and blended configuration are evaluated using numerical simulations. The results indicate that the solar absorption increases proportional to the size of the Au-NR assembly, and the best configuration is obtained for a tetramer structure. By using different blended arrangements such as single Au monomers, dimers, trimmers, and tetramers nanorods, it is possible to obtain solar weighted absorption coefficients close to an ideal solar thermal collector, even obtained at low volume fraction (1×10(−5)). Moreover, the results show an enhancement of the temperature of 58.45 °C for tetramer compared with a monomer structure, both under one sun excitation. Therefore, the Au-NR assembly shows a high potentiality to be explored as a high-performance working fluid for solar thermal collectors.

Palavras-Chave: colloids; plasmons; nanoparticles; solar collectors; thermal conductivity; gold

FAROOQ, SAJID; RATIVA, DIEGO; SAID, ZAFAR; ARAUJO, RENATO E. de. High performance blended nanofluid based on gold nanorods chain for harvesting solar radiation. Applied Thermal Engineering, v. 218, p. 1-7, 2023. DOI: 10.1016/j.applthermaleng.2022.119212. Disponível em: http://repositorio.ipen.br/handle/123456789/33366. Acesso em: $DATA.

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Abstract: Since the ideal cascade theory, several mathematical models have been developed to improve the understanding of isotopic separation cascades. Despite numerous advances in modeling multicomponent and transient cascades, there has not yet been a model that takes into account the individual centrifuges' operating conditions and separative power. This study analyses how the number of centrifuges in a stage relates to the pressure drop in the pipes, which in turn affects the centrifuges’ separative power. It estimates the local operating conditions, checks them against the mass balances in the pipes and, then, calculates the separative performance of the centrifuges. Results were presented for a stage with 40 generic centrifuges. There was a sharp pressure drop in the extremities of the stage that caused roughly 15% and 30% pressure loss in the feed and product pipes, respectively, which caused the last centrifuge to yield a separative power 14% lower than the first one.

Palavras-Chave: cascade theory; isotope separation; uranium; gas centrifuges; mathematical models

PAULA, RENATA R.R. de; MIGLIAVACCA, SYLVANA C.P.; GUARDANI, ROBERTO. Study on the operating conditions of centrifuges and their individual separative power in a stage of an isotope separation cascade. Annals of Nuclear Energy, v. 177, p. 1-7, 2022. DOI: 10.1016/j.anucene.2022.109305. Disponível em: http://repositorio.ipen.br/handle/123456789/33364. Acesso em: $DATA.

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Abstract: Lycopene is a hydrocarbon-carotenoid commonly found in red fruits intake with major function correlated to antioxidative capacity in several pathological conditions, including cancer and cardiovascular diseases. Recently, lycopene has been associated with hematopoiesis, although the effects on B lymphocyte differentiation and antibody production are poorly understood. In this work, the principal aim was to investigate whether lycopene affects B lymphopoiesis and terminal differentiation into plasma cells. Distinct in vivo and in vitro strategies based on lycopene supplementation were used direct in Balb/c mice or in culture systems with cells derived of these mice. In the bone marrow, lycopene expanded B220+IgM- progenitor B cells and B220+IgM+ immature B lymphocytes. In the spleen, lycopene induced terminal CD138+ plasma cell generation. In the blood, we found prominent IgA and low IgM levels after lycopene administration. Interestingly, the pattern of peritoneal IgM+ and IgA+ B cells indicated a significant IgM-to-IgA class switching after lycopene injection. These data indicated that lycopene induces B cell differentiation into IgA-producing plasma cells. Thus, a new cellular function has been attributed to lycopene for B lymphocyte biology and possibly associated with humoral responses and mucosal immunity.

Palavras-Chave: hydrocarbons; carotenoids; immunology; lymphocytes; cell differentiation

ELIAS, MONIQUE B.; TEODORO, ANDERSON J.; LEMOS, FELIPE S.; BERNARDES, EMERSON S.; SANTOS, SOFIA N.; PACHECO, SIDNEY; OLIVEIRA, FELIPE L. de. Lycopene induces bone marrow lymphopoiesis and differentiation of peritoneal IgA-producing cells. Anais da Academia Brasileira de Ciências, v. 94, p. 1-13, 2022. Suppl. 3, DOI: 10.1590/0001-3765202220210002. Disponível em: http://repositorio.ipen.br/handle/123456789/33362. Acesso em: $DATA.

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Abstract: The design of nanomaterials by tailoring the size, shape, and surface chemistry has a significant impact on their properties. The fine-tuning of structural defects of ceria rod-like and cube-like-shaped nanoparticles was performed via La3+ doping in molar ratios of 0–70 mol %. Morphology control was achieved by varying the hydrothermal synthesis temperature. For LaxCe1–xO2–x/2 samples prepared at 110 °C, nanorod-like structures are obtained for x < 0.30 and a random morphology of interconnecting polyhedra is achieved for a larger x. The ceria fluorite crystalline structure is maintained at an x of up to 0.60, and both Raman and X-ray diffraction results indicate a high level of defects and disorder in the crystalline structure. For LaxCe1–xO2–x/2 samples prepared at 180 °C, cube-shaped particles are predominant for an x of up to 0.10; however, for x> 0.20, two fluorite phases with different lattice parameters are associated with two distinct shapes, cubes and rods The La concentration in nanocubes is limited to x = 0.10 even for samples prepared with higher nominal La concentrations, whereas the nanorods contain larger La concentrations. The demonstrated morphology and defect control on La-doped ceria nanoparticles are critical for applications such as high-temperature oxide catalysts.

Palavras-Chave: enzymes; angiotensin; catalysts; polypeptides; temperature dependence

TRINDADE, FABIANE J.; DAMASCENO, SERGIO; OTUBO, LARISSA; FELEZ, MARISSOL R.; FLORIO, DANIEL Z. de; FONSECA, FABIO C.; FERLAUTO, ANDRE S. Tuning of shape, defects, and disorder in lanthanum-doped ceria nanoparticles: implications for high-temperature catalysis. ACS Applied Nano Materials, v. 5, n. 7, p. 8859-8867, 2022. DOI: 10.1021/acsanm.2c00942. Disponível em: http://repositorio.ipen.br/handle/123456789/33360. Acesso em: $DATA.

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