Navegação por ano de publicação "2023"

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  • IPEN-DOC 29718

    FAROOQ, SAJID ; VITAL, CAIO V.P.; TIKHONOWSKI, GLEB; POPOV, ANTON A.; KLIMENTOV, SERGEY M.; MALAGON, LUIS A.G.; ARAUJO, RENATO E. de; KABASHIN, ANDREI V.; RATIVA, DIEGO. Thermo-optical performance of bare laser-synthesized TiN nanofluids for direct absorption solar collector applications. Solar Energy Materials and Solar Cells, v. 252, p. 1-10, 2023. DOI: 10.1016/j.solmat.2023.112203

    Abstract: Titanium nitride (TiN) nanoparticles (NPs) look very promising for solar energy harvesting owing to a strong plasmonic absorption with the maximum in the near-infrared range. However, the synthesis of TiN nanofluids is very challenging as one has to combine the plasmonic feature and long-term colloidal stability to withstand harsh conditions of direct absorption solar collectors (DASC). Here, we explore solutions of bare (ligand free) TiN NPs synthesized by pulsed laser ablation in acetone as the nanofluid. We show that such NPs are low size-dispersed (mean size 25 nm) and exhibit a broad absorption peak around 700 nm, while their negative charge ensures a prolonged electrostatic stabilization of solutions. Solar weighted absorption coefficient of such TiN nanofluids reaches 95.7% at very low volume fractions (1.0 × 10−5), while nanofluid temperature can be increased up to 29 °C under 1.25-sun illumination. Our data evidence that the thermal efficiency of a DASC using TiN nanofluid is 80% higher compared to Au-based counterparts. The recorded high photothermal efficiency and excellent colloidal stability of TiN nanofluids promises a major advancement of DASC technology, while laser-ablative synthesis can offer easy scalability and relative cost-efficiency required for the implementation of systems for solar energy harvesting.

    Palavras-Chave: nanofluids; titanium nitrides; plasmons; solar energy; lasers; ablation

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  • IPEN-DOC 29878

    SILVA, RICARDO M. e; SOUZA, FERNANDA de L.; DIAS, EDUARDO; SILVA, GELSON T. dos S.T. da; DURAN, FLORYMAR E.; REGO, ARJUN; HIGGINS, DREW; RIBEIRO, CAUE. The role of TiO2:SnO2 heterojunction for partial oxidation of methane by photoelectrocatalytic process at room temperature. Journal of Alloys and Compounds, v. 968, p. 1-7, 2023. DOI: 10.1016/j.jallcom.2023.172090

    Abstract: Partial Oxidation of Methane into hydrocarbons using photoelectrochemical routes is attractive from a sustainability point of view owing to the possibility of using renewable energy (i.e., solar illumination) to activate this stable molecule. However, the process demands the development of novel catalysts that can promote methane activation and oxidation in a controlled manner to increase energy conversion efficiency. Herein, we demonstrated that semiconductor heterostructures improved charge separation compared to the individual materials alone. A more effortless transfer between bands favors the separation of the electron-hole (e− /h+) pairs generated by the photoelectrocatalytic system and prevents them from recombining. This process produces reactive oxygens, essential to driving methane oxidation conversion of the C–H bond cleavage. TiO2:SnO2 semiconductor heterojunction catalysts in film shape were investigated for methane oxidation via a photoelectrocatalytic process. The methane oxidation reactions were carried out in an inflow and sealed electrochemical system for 1 h. Liquid-state nuclear magnetic resonance revealed methanol and acetic acid as the main liquid products, where the TiO2:SnO2 heterojunction exhibited better performance with values of 30 and 8 µmol. cm− 2 .h− 1 , respectively. Compared to their materials alone, the superior performance of the TiO2:SnO2 heterojunction is attributed to the formation of heterostructure type II that enables a more effortless transfer between bands, facilitating the separation of the generated e− /h+ pairs under UV-Vis irradiation. The outcomes achieved here will motivate further studies for developing semiconductor heterojunction structure catalysts in photoelectrocatalysis to partially oxidize methane into valuable chemicals.

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  • IPEN-DOC 29893

    CARBONE, D.; AGODI, C.; BELLONE, J.I.; BURRELLO, S.; CALABRESE, S.; CAPPUZZELLO, F.; CAVALLARO, M.; COLONNA, M.; DE GREGORIO, G.; FERREIRA, J.L.; GARGANO, A.; LENSKE, H.; SGOUROS, O.; SPATAFORA, A.; ACOSTA, L.; AMADOR-VALENZUELA, P.; BRISCHETTO, G.A.; CALVO, D.; CAPIROSSI, V.; CHÀVEZ LOMELÌ, E.R.; CIRALDO, I.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; GUAZZELLI, M.A.; HACISALIHOGLU, A.; IAZZI, F.; LAY, J.A.; LINARES, R.; LUBIAN, J.; MEDINA, N.H.; MORALLES, M. ; OLIVEIRA, J.R.B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RUSSO, G.; SOLAKCI, S.O.; SOUKERAS, V.; SOULIOTIS, G.; TORRESI, D.; TUDISCO, S.; YILDIRIM, A.; ZAGATTO, V.A.B.. The NUMEN project: probing nuclear response to weak interaction by nuclear reactions. Journal of Physics: Conference Series, v. 2586, p. 1-4, 2023. DOI: 10.1088/1742-6596/2586/1/012133

    Abstract: Different reactions channels induced by the 18O + 40Ca collisions at 275 MeV incident energy are simultaneously measured and analysed consistently within the same reaction and structure frameworks within the NUMEN project. The project aims to provide data-driven information for the determination of the nuclear matrix elements involved in the neutrinoless double beta decay. In particular, the elastic and inelastic scattering, one- and two-proton transfer, one-neutron transfer, and single charge exchange reactions are explored. The full quantum-mechanical calculations, performed by including microscopic nuclear structure inputs, describe well all the experimental data, giving support to a multi-channel strategy for the analysis of heavy-ion induced direct reactions.

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  • IPEN-DOC 30160

    SILVA, BARBARA P.G. ; OTUBO, LARISSA . The influence of PVP molecular weight in the synthesis of silver nanowires using a salt-assisted polyol method. In: BRAZIL MRS MEETING, 21st, October 1-5, 2023, Maceió, AL. Abstract... São Carlos, SP: Aptor Software, 2023. p. 877-877.

    Abstract: In the last decades, the demand for new materials to be used in electronic devices has increased. Among the materials that can be used in transparent conductive films (TCFs), are the silver nanowires (AgNWs). This class of material, when supported in glass or PET, e.g., has good conductivity, thermal and mechanical properties and also high transparency. In this work, the AgNWs were synthesized using the polyol method assisted by a salt and the influence of molecular weight of the capping agent polyvinylpyrrolidone (PVP) in the morphology and structure of Ag crystals was investigated. Different molecular weight of PVP (40 K, 120 K, 360 K and 1300 K MW) was used in the synthesis. The surface morphology of the products was observed by scanning electron microscopy and atomic force microscopy. The phase composition and structure were analyzed by X-ray diffraction (XRD) and the XRD patterns diffraction peaks correspond with the face-centered-cubic (fcc) crystalline phase of silver. Transmission electron microscopy was used to analyze the crystal structure, and UV-visible spectroscopy was used to follow the formation of Ag structures. The results indicate that PVP and its chain length have an important role in the formation of silver nanocrystals due to the adsorption and steric effects [1] and as high is the molecular weight of PVP, longer and thinner are the AgNWs as observed by other authors [2]. Different morphologies were obtained when changing the size of PVP chain. For smaller MW of PVP, particles and short wires were formed. Increasing the MW, nanorods and pyramidal particles were formed, and finally, forming nanowires when using the highest MW PVP of the experiments.Improving the aspect ratio of silver nanowires is important to construct TCFs, since the conductivity and transparency properties are improved when they are thinner and longer.

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  • IPEN-DOC 29886

    PAOLINI, TIAGO B.; ASSUNCAO, ISRAEL P.; COSTA, ISRAEL F.; BLOIS, LUCCA; FELINTO, MARIA C.F.C ; MOURA JUNIOR, RONALDO T.; TEOTONIO, ERCULES E.S.; MALTA, OSCAR L.; CARNEIRO NETO, ALBANO N.; BRITO, HERMI F.. The influence of imidazolium counterions on the luminescence properties of Cnmim[Eu(tta)4] tetrakis complexes in solid-state and ionic liquid solutions. Journal of Luminescence, v. 263, p. 1-11, 2023. DOI: 10.1016/j.jlumin.2023.120158

    Abstract: A series of lanthanide tetrakis complexes Cnmim[Ln(tta)4] where Ln3+: Eu3+ and Gd3+, Cnmim: imidazoliumbased counterions (n from 3 to 8) and tta: thenoyltrifluoroacetonate were synthesized by a one-pot method. The Cnmim[Ln(tta)4] complexes are thermostable up to 210 ◦C and present an isomorphic-like character for the complexes with n = 5, 6, and 7. The phosphorescence spectral profile of the Cnmim[Gd(tta)4] complexes showed intense emission broadbands, in which the barycenters are slightly shifted to energies from the 18,950 to 18,450 cm− 1 range. The Cnmim[Eu(tta)4] complexes in solutions of the corresponding [Cnmim]Br ionic liquids show similar emission spectral profiles as their corresponding in the solid state, indicating that the coordination polyhedron does not undergo a significant variation when the chemical environment is changed. Relatively high values of the intensity parameter Ω2 in both media are presented. The Ω4 values of the complexes in solutions of ionic liquids are also similar, reinforcing that there are small changes in the polyhedral coordination from the solid state to the ionic liquid solution. The series presents high intrinsic emission quantum efficiencies, 90% ≥ QEu Eu ≥ 53%. In addition, theoretical calculations on the intramolecular energy transfer (IET) reveal the participation of the 7 F0→5 D1 and 7 F1→5 G2 transitions for the IET via S1 while the IET via T1 state is dominated by the 7 F0→5 D1 and 7 F1→5 D0 transitions. Therefore, due to their high luminescent features, these Eu3+ tetrakis complexes are potential candidates to be applied as optical markers in the solid-state or even in ionic liquid solutions.

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  • IPEN-DOC 29636

    SABINO, CAETANO P.; RIBEIRO, MARTHA S. ; WAINWRIGHT, MARK; ANJOS, CAROLINA dos; SELLERA, FABIO P.; DROPA, MILENA; NUNES, NATHALIA B.; BRANCINI, GUILHERME T.P.; BRAGA, GILBERTO U.L.; ARANA-CHAVEZ, VICTOR E.; FREITAS, RAUL O.; LINCOPAN, NILTON; BAPTISTA, MAURICIO S.. The biochemical mechanisms of antimicrobial photodynamic therapy. Photochemistry and Photobiology, v. 99, n. 2, p. 742-750, 2023. DOI: 10.1111/php.13685

    Abstract: The unbridled dissemination of multidrug-resistant pathogens is a major threat to global health and urgently demands novel therapeutic alternatives. Antimicrobial photodynamic therapy (aPDT) has been developed as a promising approach to treat localized infections regardless of drug resistance profile or taxonomy. Even though this technique has been known for more than a century, discussions and speculations regarding the biochemical mechanisms of microbial inactivation have never reached a consensus on what is the primary cause of cell death. Since photochemically generated oxidants promote ubiquitous reactions with various biomolecules, researchers simply assumed that all cellular structures are equally damaged. In this study, biochemical, molecular, biological and advanced microscopy techniques were employed to investigate whether protein, membrane or DNA damage correlates better with dose-dependent microbial inactivation kinetics. We showed that although mild membrane permeabilization and late DNA damage occur, no correlation with inactivation kinetics was found. On the other hand, protein degradation was analyzed by three different methods and showed a dose-dependent trend that matches microbial inactivation kinetics. Our results provide a deeper mechanistic understanding of aPDT that can guide the scientific community toward the development of optimized photosensitizing drugs and also rationally propose synergistic combinations with antimicrobial chemotherapy.

    Palavras-Chave: antimicrobial agents; photodynamic therapy; biochemical reaction kinetics; microbial drug resistance

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  • IPEN-DOC 29809

    BLAAUW, MENNO; D'AGOSTINO, GIANCARLO; DI LUZIO, MARCO; DUNG, HO MANH; JACIMOVIC, RADOJKO; DIAS, MAURO da S. ; SEMMLER, RENATO ; VAN SLUIJS, ROBBERT; BARRADAS, NUNO P.. The 2021 IAEA software intercomparison for k0‑INAA. Journal of Radioanalytical and Nuclear Chemistry, v. 332, n. 8, p. 3387-3400, 2023. DOI: 10.1007/s10967-022-08626-1

    Abstract: In order to establish the variation between results in mass fractions due to software implementation, as measured by the k0-method for INAA, the IAEA has organized a software intercomparison. A complete set of test spectra and associated information was assembled. Efficiency curves, neutron spectrum parameters, correction factors and mass fractions were calculated with the participating programs (k0-IPEN, k0-INRIM, k0-DALAT, k0-IAEA and KayWin) using identical peak areas. In this paper, we report on the observed discrepancies, causes, remedies and future software developments. The test data, as well as intermediate results and observed mass fractions of the certified reference material BCR-320R “channel sediment” are available through the IAEA on request. The variations in concentrations attributed to differences between the programs were initially found to be 5.6 and 7.9%, for certified and uncertified concentrations, respectively. After the certified concentrations had been made available to the participants and they had been allowed to improve their programs, the variations found were 2.7 and 3.4%, respectively. The main identified remaining causes of variation are differences in the procedures used for detector efficiency characterisation and neutron spectrum parameter determination.

    Palavras-Chave: ge semiconductor detectors; interlaboratory comparisons; neutron activation analysis; neutron flux; triga type reactors

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  • IPEN-DOC 29849

    AYLLON, R.M. ; FURLAN, M.R.; EL HAJJ, T.M.; SILVA, P.S.C. . Th-232 radiological aspects of carbonate niobium mining waste use as agricultural amendment. Brazilian Journal of Radiation Sciences, v. 11, n. 1A, p. 1-21, 2023. DOI: 10.15392/2319-0612.2023.2223

    Abstract: The use of mining residues in agriculture may be possible, as long as there be previous studies in different areas, one of them being the analysis of the involved radionuclides behavior. This study determined the concentrations of 232Th activity in soil, soil treated with lime, soil with carbonate residue from niobium mining, soil with the mixture of lime and carbonate, in two moments. The transfer factor of 232Th from the soil to the plant was analyzed, in this case, lettuce (n=20), in the different types of treatment and in two moments. The addition of carbonate to the soils did not significantly alter the levels of radioactivity for 232Th radionuclide in lettuce. The effective dose resulting from the lettuce ingestion varied from 0.09 to 0.3 µSv y-1.

    Palavras-Chave: agriculture; carbonates; mining; neutron activation analysis; niobium; radiation protection; soils; tailings; thorium 232

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  • IPEN-DOC 29942

    MANHANI, KELLY C.; LACERDA, JOAO P.A. de; NAKANO, VIVIANE E.; CRUZ, LUCAS M.S.; COSTA, ALAN R.; BUSTILLOS, JOSE O.W.V. . Técnicas analíticas para o controle de resíduos de agrotóxicos em alimentos cítricos / Analytical techniques for pesticide residues control in citrus foodstuffs. Revista IPT, v. 8, n. 23, p. 61-82, 2023.

    Abstract: O Brasil é o maior produtor mundial de laranja, responsável pela exportação de três quartos de suco de laranja consumidos no mundo. Devido a posição de destaque na cadeia agroindustrial, a segurança alimentar é item fundamental para garantir a sustentabilidade produtiva, qualidade e competitividade de mercado. Dado a sua importância, com o objetivo de avaliar a qualidade dos citros, neste trabalho foram estudados três métodos de extração: “QuEChERS ORIGINAL”, “QuEChERS Acetato MODIFICADO” e extração Líquido-Líquido, com a utilização dos equipamentos GC/ECD e GC/MS para quantificação e confirmação dos analitos. O método QuEChERS está revolucionando o preparo de amostras de matrizes complexas, e neste estudo, foram avaliados a mudança de pH na extração bem como a proporção de amostra e adição de diferentes sais e adsorventes na etapa de limpeza da amostra (Clean Up) para a eficiência da extração dos ingredientes ativos. Parâmetros de qualidade analítica como seletividade/efeito matriz, linearidade, limite de detecção e quantificação foram estabelecidos para cinco agrotóxicos: Trifluralina, Clorotalonil, Clorpirifós, Dicofol e Azoxistrobina. Foram analisadas um total de 26 amostras de laranja Pêra e suco de laranja, coletadas em feiras livres, supermercados, sítios com produção local e restaurantes da cidade de São Paulo, dentre as quais, três amostras de suco analisadas durante o desenvolvimento apresentaram indícios do agrotóxico Dicofol, proibido pela legislação brasileira.

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  • IPEN-DOC 29887

    SANTOS, BIANCA P.S. ; BARBOSA, ANDREY S. ; KODAMA, YASKO ; THIAGO, QUEIROZ B. de; SANTIAGO, ELISABETE I. . Tailoring highly stable anion exchange membranes with graft molecular structure ordering using reversible addition-fragmentation chain transfer polymerization for alkaline fuel cells. Journal of Membrane Science, v. 687, p. 1-12, 2023. DOI: 10.1016/j.memsci.2023.122071

    Abstract: The radiation-induced grafting is used to prepare a variety of anion-exchange membranes (AEM) based on poly (ethylene-co-tetrafluoroethylene) (ETFE) utilizing a reversible addition-fragmentation chain transfer (RAFT) agent. The copolymerization process is controlled by the RAFT agent, resulting in AEMs with a restricted molecular weight dispersion. As a result, RAFT-AEMs exhibit decreased water uptake and reduced swelling. A significant improvement in thermal and mechanical characteristics is evidenced, while the conductivity remains practically unaltered. Anion-exchange membrane fuel cell (AEMFC) tests revealed that conventional RIG-AEMs and RAFT-AEMs with low RAFT content (5 wt%) have comparable beginning-of-life performances (~0.95 W cm− 2 ). However, for higher RAFT contents, the performance trends to decrease indicating an imbalance in water management. Furthermore, short-term stability tests suggest that RAFT-AEMs are able to operate highly stable, with a conductivity rate loss of 0.05% h− 1 , which represents an improvement of 160% in comparison to conventional RIG-AEM. AFM analysis demonstrated that structural ordering molecular and morphology tailor the fundamental properties of ETFE-based AEMs, combining enhanced performance and stability for alkaline fuel cell applications.

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  • IPEN-DOC 30166

    BUGARIN, ALINE de F.S. ; VIVEIROS, BARBARA V.G. de ; TERADA, MAYSA; GUILHERME, LUIS H.; NEVES, MAURICIO D.M. das ; COSTA, ISOLDA . Syringe cell method to study the corrosion resistance of the UNS S32101 lean duplex stainless steel welded by the gas tungsten arc welding double fusion (GTAW-DF). In: BRAZIL MRS MEETING, 21st, October 1-5, 2023, Maceió, AL. Abstract... São Carlos, SP: Aptor Software, 2023. p. 1178-1178.

    Abstract: This work aims to investigate the corrosion performance of the UNS S32101 lean duplex stainless steel (LDSS) welded by the gas tungsten arc welding double fusion (GTAW-DF). In the study, six welded samples were manufactured with different welding parameters. A Syringe cell was used to characterize the electrochemical behavior of the different welded zones by potentiodynamic polarization tests in NaCl 3,5 % (w.t.) and in a solution of citric acid with addiction of NaCl to simulate the food industry. The results showed that the welding parameters tested significantly affected the corrosion resistance of the LDSS UNS S32101. Besides, a correlation was stablished between microstructure and electrochemical behavior of fusion line (FL), heat affected zone (HAZ) and fusion zone (FZ).

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  • IPEN-DOC 30145

    ROSERO, WILMMER A.A. ; BARBEZAN, ANGELICA B. ; ROSTELATO, MARIA E.C.M. ; SOUZA, CARLA D. de ; NOGUEIRA, BEATRIZ R. ; ZEITUNI, CARLOS A. . Synthesis, activation and application testing of gold nanoparticles for nanobrachytherapy. In: INTERNATIONAL SYMPOSIUM ON TRENDS IN RADIOPHARMACEUTICALS, April 17-21, 2023, Vienna, Austria. Abstract... Vienna, Austria: International Atomic Energy Agency - IAEA, 2023. p. 24-24.

    Abstract: For more than 50 years, the Energy and Nuclear Research Institute IPEN, has been offering solutions to Brazil through nuclear technology. Thus, one of the main areas where IPEN has contributed assertively is medicine. Reaching the level of 32 radiopharmaceuticals and radioactive sources intended both for therapy and for the diagnosis of several pathologies, including cancer, which are obtained with the help of the two nuclear reactors and two cyclotrons present in the institution. The Institute has a team for the development, production and distribution of radioactive sources for brachytherapy, such as 192 Ir wires and 125 I seeds. Brachytherapy is a cancer treatment technique where the radioactive source is placed close to or in contact with the lesion. The great advantage of the technique is to save healthy tissues. Currently, we are working on obtaining nanometric materials that can be applied in the emerging nano brachytherapy, because of its properties and characteristics at the nanometric level, gold has been the subject of studies and tests. Elemental Au gold can be activated 198 Au inside a nuclear reactor, and has β- decay and a half-life of 2.7 days, which makes it ideal for short-term irradiations. In addition, gold in the form of nanoparticles has a completely different chemistry, with gold nanoparticles (AuNPs) being easily functionalized by a large part of molecular and polymeric binders, which may present favorable characteristics for the studies, and together with AuNPs they are able to work synergistically to achieve greater efficiencies. Currently, AuNPs have been successfully functionalized with gum arabic (GA), a coating widely used in the cosmetic and food industry, which is low cost and along with nanoparticles has shown biocompatibility with different cell groups and has been shown to be very stable over time. The project includes studies regarding the synthesis of nanoparticles, coating, cytotoxicity of AuNPs in vitro "cold" (non-radioactive) and the development of activation protocols in the nuclear reactor. In the next phase, after activation, in the reactor, "hot" tests will be performed in vitro and in vivo.

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  • IPEN-DOC 29614

    MELO, A.D.; SILVA, J.P. da; NOBRE, F.X.; COSTA, S.; SALES JUNIOR, J.C.C.; ANGLADA-RIVERA, J.; GUERRERO, F.; PAULA, M.M. da S.; SOUZA, R.F.B. de ; PENA-GARCIA R.; AGUILERA, L.; LEYET, Y.. Synthesis microwave-assisted: fast method to obtain lithium-doped sodium titanate. Journal of Materials Science: Materials in Electronics, v. 34, n. 6, p. 1-10, 2023. DOI: 10.1007/s10854-023-09948-w

    Abstract: In this work, the variation in the structural and electrical properties of lithium-doped sodium titanate, obtained from an ultrafast (15 min) microwave-assisted synthesis has been reported. X-ray diffraction and Rietveld analysis have been done to identify the present phases, their composition, and lattice parameters. Na2Ti3O7 was identified as the major phase, while Na2Ti6O13 was obtained as a secondary phase in all samples. The phase composition usually varies depending on the content of the doping element. In the sample with 0.5% lithium ions, an additional phase corresponding to NaLiTi3O7 appeared. The microstructure of the ceramic samples showed an increase in the grains size and the appearance of small particles on the surface of the grains. This effect becomes more evident for the samples with 0.5% Li. Finally, the electrical properties of the ceramic samples studied were favored with an increase in doping and σdc values of 1.94 × 10− 5 S cm− 1, 2.51 × 10− 5 S cm− 1, and 4.00 × 10− 5 S cm− 1 were determined for Na2 − xLixTi3O7 with x = 0.0%, 0.1%, 0.5% of Li+.

    Palavras-Chave: sodium compounds; titanates; microwave radiation; lithium; doped materials

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  • IPEN-DOC 29602

    LOPES, ISABELA S.; CASSAS, FERNANDO; VEIGA, THIAGO A.M.; SILVA, FLAVIA R. de O. ; COURROL, LILIA C.. Synthesis and characterization of Eugenia uniflora L. silver nanoparticles and L-cysteine sensor application. Chemistry and Biodiversity, v. 20, n. 1, p. 1-12, 2023. DOI: 10.1002/cbdv.202200787

    Abstract: L-Cysteine (Cys) is a non-essential sulfur-containing amino acid, crucial for protein synthesis, detoxification, and several metabolic functions. Cys is widely used in the agricultural, food, cosmetic, and pharmaceutical industries. So, a suitable sensitive and selective sensing approach is of great interest, and a low-cost sensor would be necessary. This article presents silver nanoparticles (EuAgNPs) synthesized by a green synthesis method using Eugenia uniflora L. extracts and photoreduction. The nanoparticles were characterized by UV/VIS, transmission electron microscopy, high-performance liquid chromatography (HPLC), FTIR, and Zeta potential. With the addition of Cys in the EuAgNPs solution, the terminal thiol part of L-cysteine binds on the surface of nanoparticles through Ag−S bond. The EuAgNPs and CysAgNPs coexist until flavonoids bound the amino group of Cys, enhancing the red color of solutions. The EuAgNPs provided selectivity to detect Cys among other amino acids, and its detection limit was found to be 3.8 nM. The sensor has the advantages of low-cost synthesis, fast response, high selectivity, and sensitivity.

    Palavras-Chave: trees; cysteine; amino acids; silver; nanoparticles; photochemistry; reduction

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  • IPEN-DOC 29717

    CECCHI, CLAUDIA R. ; ALSING, SIDSEL; JESUS, GUSTAVO P.P. ; ZACARIAS, ENIO A. ; KJAER, LISBETH; CLEMENT, MICHELLE S.; KUMAGAI-BRAESCH, MAKIKO; CORYDON, THOMAS J.; BARTOLINI, PAOLO ; PERONI, CIBELE N. ; AAGAARD, LARS. Sustained secretion of human growth hormone from TheraCyte devices encapsulated with PiggyBac-engineered retinal pigment epithelium cells. Tissue and Cell, v. 82, p. 1-13, 2023. DOI: 10.1016/j.tice.2023.102095

    Abstract: Growth hormone (GH) deficiency is characterized by impaired growth and development, and is currently treated by repeated administration of recombinant human GH (hGH). Encapsulated cell therapy (ECT) may offer a less demanding treatment-strategy for long-term production and release of GH into circulation. We used PiggyBac-based (PB) transposon delivery for engineering retinal pigment epithelial cells (ARPE-19), and tested a series of viral and non-viral promoters as well as codon-optimization to enhance transgene expression. Engineered cells were loaded into TheraCyte macrocapsules and secretion was followed in vitro and in vivo. The cytomegalovirus (CMV) promoter supports strong and persistent transgene expression, and we achieved clonal cell lines secreting over 6 µg hGH/106 cells/day. Codon-optimization of the hGH gene did not improve secretion. ARPE-19 cells endured encapsulation in TheraCyte devices, and resulted in steady hormone release for at least 60 days in vitro. A short-term pilot experiment in immunodeficient SCID mice demonstrated low systemic levels of hGH from a single 40 µL capsule implanted subcutaneously. No significant increase in weight increase or systemic hGH was detected after 23 days in the GH-deficient lit/SCID mouse model using 4.5 µL capsules loaded with the highest secreting clone of ARPE-19 cells. Our results demonstrate that PB-mediated engineering of ARPE-19 is an efficient way to generate hormone secreting cell lines compatible with macroencapsulation, and our CMV-driven expression cassette allows for identification of clones with high level and long-term secretory activity without addition of insulator elements. Our results pave the way for further in vivo studies of encapsulated cell therapy.

    Palavras-Chave: hormones; sth; epithelium; pigments; therapy

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  • IPEN-DOC 29938

    FERREIRA, MAURICIO L.; DALMAS, FABRICIO B.; SANTANNA, MARYLY; RODRIGUES, ELAINE A. ; SODRE, MARCELO G.. Sustainable development in São Paulo's Green Belt Biosphere Reserve: between the void of municipal environmental policies and the ecosystem management of the territory / Desenvolvimento sustentável na Reserva da Biosfera do Cinturão Verde de São Paulo: entre o vazio das políticas ambientais municipais e a gestão ecossistêmica do território. Revista de Gestao Ambiental e Sustentabilidade, v. 12, n. 1, p. 1-37, 2023. DOI: 10.5585/2023.22940

    Abstract: Introduction: The Green Belt Biosphere Reserve, with 2.33 million hectares and its internal urban area with 220 thousand hectares, is configured as a water security territory and expresses a direct relationship between urban development and areas that ensure well-being and ecosystem services for 12% of Brazil's population. With seventy-eight municipalities that fully or partially integrate the GBBR, the socioeconomic differences and the different contexts of urbanization and governance reflect on territorial management at the local level and impact the environmental and regional sustainable development agendas. Objective: Based on a survey of environmental policies and correlations between economic and socio-environmental indicators on a municipal scale for the entire study area, this article assesses the level of development of the main environmental public policies and identifies the relationship between these policies and socio-environmental indicators. Originality: Although the Green Belt Biosphere Reserve is an area recognized by the United Nations (UN), the management of its territory depends on municipal actions that comprise it. Little attention has been paid to environmental management, especially in terms of public environmental policies and a broad and ongoing understanding of the conservation of this area. Results: The analysis shows that the different municipalities in the GBBR have different levels of implementation regarding Environmental Agenda. When considering the Municipal Plans for Urban Afforestation, Adaptation to Climate Change, Atlantic Forest and Solid Waste, only Guarujá, Mogi das Cruzes, Santos and São Paulo have these four policies in preparation or completed, while for 33.3% (n=25) of the municipalities, none of these agendas was developed, and a positive correlation was identified between the HDI and the largest number of implemented policies. Contribution: Large and medium-sized cities in the state of Sao Paulo, Brazil, present studies addressing ecological patterns and processes, however, they do not address specific questions on the environmental sector itself, which this paper aimed at providing. Conclusion: As the Green Belt accounts for 72% of the volume of drinking water in all of São Paulo, the disparities between the municipal indicators analyzed reinforce the need to adopt the GBBR as a platform for adequate governance to integrate policies at different scales for sustainable regional development. Systemic efforts are needed, especially at the municipal scale, in order to carry out adequate environmental management of the GBBR territory.

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  • IPEN-DOC 29897

    STIPP, WAGNER ; MORAIS, NATHANAEL W.S. ; MARTINS, JOSÉ V.; MATOS, PRISCILA ; ROSSI, JESUALDO L. ; ROSSI, WAGNER de ; RAELLE, MARCUS P. . Surface contaminants’ incorporation after nanosecond laser ablation. Journal of Radioanalytical and Nuclear Chemistry, v. 332, n. 11, p. 4535-4540, 2023. DOI: 10.1007/s10967-023-09153-3

    Abstract: Decontamination and cleaning of surface-contaminated radioactive waste using laser ablation is a promising new technique being researched. One advantage is the potential to recycle waste and reduce the demand for repository storage. However, prior studies have shown that residual radioactivity can persist after laser decontamination indicating the incorporation of contaminants beneath the surface of metal samples. In this study, a q-switched laser was used to measure the depth of the recast zone at various fluences and simulate a decontamination process using a gold-coated sample. The results showed that surface material was found in the recast zone for fluences ranging from 1 to 10 J/cm2. This suggests that incorporation of surface contaminants after laser ablation is an important issue that must be considered before using this technique for radioactive waste treatment.

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  • IPEN-DOC 29058

    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

    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

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  • IPEN-DOC 29621

    PRADO, FELIPE M. ; FRANCO, TOMAS J. ; WETTER, NIKLAUS U. . Sub-nanosecond, 41 mJ pulse energy, passively Q-switched Nd:YLF laser. Optics and Laser Technology, v. 162, p. 1-6, 2023. DOI: 10.1016/j.optlastec.2023.109257

    Abstract: A sub-nanosecond, diode-stack side-pumped, passively Q-switched Nd3+:YLF4/Cr4+:YAG Laser is reported in a compact cavity design, generating one pulse of 41 mJ with a pulse width of 894 ps, achieving a peak output power of 46 MW and beam quality M2 of 5.4 × 5.9 (HxV). The number of pulses in the pulse train could be adjusted from one pulse to ten pulses of 111 mJ total output energy and 23.7 % optical efficiency by adjusting the focus distance while maintaining sub-nanosecond pulse duration. This resonator can also be used for high-power simultaneous Q-switched laser emission at 1047 nm and 1053 nm.

    Palavras-Chave: q-switching; high energy physics; crystals; pumping

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  • IPEN-DOC 30184

    CATARINA, MARCUS V. ; BERECZKI, ALLAN ; WETTER, NIKLAUS U. . Sub-nanosecond microchip oscillator for a MOPA system tailored for tattoo removal. In: INTERNATIONAL CONFERENCE ON OPTICAL MEMS AND NANOPHOTONICS; SBFOTON INTERNATIONAL OPTICS AND PHOTONICS CONFERENCE, July 31 - August 3, 2023, Campinas, SP. Proceedings... Piscataway, NJ, USA: IEEE, 2023. DOI: 10.1109/OMN/SBFOTONIOPC58971.2023.10230921

    Abstract: In this work we study a microchip laser designed to function as an oscillator in a Master-Oscillator Power-Amplifier (MOPA) system targeted for laser tattoo removal. Different configurations of the Nd: YAG resonator were used by changing the output coupler mirror reflectivities and the initial transmission of the Q-switch. The quasi-CW resonator provided 55.4 W of output with 51.31% and 78.2% optical and slope efficiencies, respectively. For Q-switched operation, the best configuration resulted in a peak output power of 3.6 MW with 588 ps pulse width.

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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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O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

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.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.