Navegação Periódicos - Artigos por ano de publicação "2023"

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  • IPEN-DOC 29723

    SOBOTYK, CAROLINE; BALDISSERA, FERNANDA G.; RODRIGUES JUNIOR, LUIZ C.; ROMAO, PEDRO R.T.; OLIVEIRA, JULIANA S. de; DORNELLES, GUILHERME L.; ANDRADE, CINTHIA M. de; MACIEL, ROBERTO M.; DANESI, CRISTIANE C.; FERREIRA, RAFAEL V. de P. ; BELLINI, MARIA H. ; BOTTON, SONIA de A.; VOGEL, FERNANDA S.F.; SANGIONI, LUIS A.. Zinc and manganese imbalances in BALB/c mice experimentally infected with Leishmania (Leishmania) amazonensis. Acta Parasitologica, v. 68, n. 2, p. 447-452, 2023. DOI: 10.1007/s11686-023-00666-1

    Abstract: Abstract Purpose The clinical progression of Leishmania (Leishmania) amazonensis infection depends on multiple factors, including immunological status of the host and their genotypic interaction. Several immunological processes depend directly on minerals for an efcient performance. Therefore, this study used an experimental model to investigate the alterations of trace metals in L. amazonensis infection associate with clinical outcome, parasite load, and histopathological lesions, and the efect of CD4+T cells depletion on these parameters. Methods A total of 28 BALB/c mice were divided into 4 groups: 1—non-infected; 2—treated with anti-CD4 antibody; 3— infected with L. amazonensis; and 4—treated with anti-CD4 antibody and infected with L. amazonensis. After 24 weeks postinfection, levels of calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), Cu, and Zn were determined by inductively coupled plasma optical emission spectroscopy using tissue samples of the spleen, liver, and kidneys. Additionally, parasite burdens were determined in the infected footpad (inoculation site) and samples of inguinal lymph node, spleen, liver, and kidneys were submitted to histopathological analysis. Results Despite no signifcant diference was observed between groups 3 and 4, L. amazonensis-infected mice had a signifcant reduction of Zn (65.68–68.32%) and Mn (65.98 to 82.17%) levels. Presence of L. amazonensis amastigotes was also detected in the inguinal lymph node, spleen, and liver samples in all infected animals. Conclusion The results showed that signifcant alterations in micro-elements levels occur in BALB/c mice experimentally infected with L. amazonensis and may increase the susceptibility of individuals to the infection.

    Palavras-Chave: protozoa; skin diseases; elements; trace amounts

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  • IPEN-DOC 29722

    SCAPIN, M.A. ; TESSARI-ZAMPIERIA, M.C. ; GUILHENA, S.N. ; COTRIM, M.E.B. . X-ray fluorescence spectrometry: an alternative technique for analysis of waste. Brazilian Journal of Radiation Sciences, v. 11, n. 1A, 2023. DOI: 10.15392/2319-0612.2023.2144

    Abstract: This study aims to develop reliable analytical methodology that is, cost-effective, and requires minimal sample quantity to quantify uranium content in nuclear waste and others. The Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) technique was used, and a rigorous comparison was made between the fundamental parameters (FP) method and the empirical (EMP) method. Statistical evaluation of results demonstrated that the FP method showed a satisfactory level of confidence for precision and limit of quantification.

    Palavras-Chave: uranium; x-ray spectroscopy; fluorescence spectroscopy; radioactive wastes; waste management

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  • IPEN-DOC 29107

    CALEGARI, RUBENS P.; SILVA, ERIC A. da ; SILVA, ANA P.M. da; GOMES, MARCELO P.; MOTA, LAYNA A.; ARTHUR, VALTER; BAPTISTA, ANTONIO S.. Wort disinfection treatment with electron beam for bioethanol production. Scientia Agricola, v. 80, p. 1-11, 2023. DOI: 10.1590/1678-992X-2021-0260

    Abstract: Microbial contamination of the wort during the fermentation process causes significant losses in ethanol production worldwide and creates a dependence of the industry on chemicals and antibiotics to control contamination. Therefore, this study used electron beam (e-beam) to disinfect wort from sugarcane (Saccharum officinarum L.) molasses and investigate the bioethanol fermentation. Four treatments (T0 – T3) were carried out using ionizing doses of radiation through the electron accelerator: 0 (control), 10, 20, and 40 kGy. Total mesophiles, total bacteria, sucrose, glucose, fructose, phenolics, flavonoids, hydroxymethylfurfural (5-HMF), and Furfural were measured. An alcoholic fermentation assay was performed after the irradiation process. The irradiated treatments showed no inversion of sugars and formation of the inhibitory by-products flavonoids, furfural and 5-HMF, except for the phenolic compounds. The lower dose tested (10 kGy) reduced more than 99.9 % of the total mesophiles and more than 99.99 % of the total bacteria in the substrate. In the fermentation, the irradiated worts presented similar (p > 0.05) yields (92, 93, and 94 %) and ethanol productivity levels (0.89, 0.88, and 0.87 g L–1 h–1, for T1, T2, and T3 respectively). However, all treatments presented higher yields and productivity (p < 0.05) when compared to the control (88 % and 0.85 g L–1 h–1), highlighting the possible use of e-beam in wort fermentation at a lower dose (10 kGy). This allows reduction in losses caused by microbial contamination, besides increasing fermentation yield and productivity with lower energy consumption.

    Palavras-Chave: microorganisms; decomposition; fermentation; alcohols; biofuels; electrons; accelerators

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  • IPEN-DOC 29883

    DEL MASTRO, NELIDA L. ; GERVASONI, JUANA L.. Women in the nuclear field driving Latin American integration. Journal of Engineering Research, v. 3, n. 35, p. 1-10, 2023. DOI: 10.22533/at.ed.3173352319107

    Abstract: Nuclear energy is used to generate electrical energy, produce radioisotopes, desalinate seawater and produce hydrogen. Nuclear and isotopic techniques contribute to the preservation of water and soil resources and to control pests, ensure food safety and greater food security, as well as improving livestock production and health. The organization of women in the nuclear field (Women in nuclear-WiN) has as one of its functions to make the public aware of the benefits that the application of nuclear energy can bring in all possible applications. This action will help to overcome restrictions from that part of the public that is reticent about using this technology and contribute to Latin American integration. Also, data crossings of the number of related publications are presented, which help to objectively analyze the trend of this integration

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  • IPEN-DOC 29721

    VIVEIROS, BARBARA V.G. de ; SILVA, REJANE MARIA P. da ; DONATUS, UYIME ; COSTA, ISOLDA . Welding and galvanic coupling effects on the electrochemical activity of dissimilar AA2050 and AA7050 aluminum alloys welded by Friction Stir Welding (FSW). Electrochimica Acta, v. 449, p. 1-15, 2023. DOI: 10.1016/j.electacta.2023.142196

    Abstract: In this work, the effects of friction stir welding (FSW) on the microstructure and electrochemical activities of dissimilar AA2050 and AA7050 aluminum alloys have been investigated. Local electrochemical tests supported by surface analytical characterization were used to study the local electrochemical activities developed along the weld zones of the dissimilar alloys. The investigation was carried out on the cross-section of the welded Al alloys. The results showed that the friction stir welding (FSW) of the dissimilar alloys affected the microstructure and the electrochemical behavior of the different regions (HAZ, TMAZ, SZ) formed by the welding process. Scanning vibrating electrode technique (SVET) and micropotentiometry by using an ion-selective microelectrode showed that TMAZ was the zone with the highest electrochemical activity. This zone corresponded to the transition region between the two welded alloys. The high electrochemical activity observed in this region was associated with the effect of welding on the microstructure and, also, with the galvanic coupling between the two alloys, where the alloy AA7050 acted as an anode and the AA2050 as a cathode. Preferential corrosion attack on the AA7050 alloy was also evident.

    Palavras-Chave: aluminium alloys; friction; welding; coupling; electrochemical corrosion; potentiometry

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  • IPEN-DOC 29902

    MEDINA, MIDILANE S. ; CARVALHO, SABRINA G.M. ; TABUTI, FRANCISCO N. ; MUCCILLO, ELIANA N.S. ; FONSECA, FABIO C. ; MUCCILLO, REGINALDO . W-doped Lanthanum Molybdenum Oxide/Lithium-Sodium-Potassium Carbonate Composite Membranes for Carbon Dioxide Permeation. Materials, v. 16, n. 14, p. 1-14, 2023. DOI: 10.3390/ma16145128

    Abstract: Single-phase tungsten-doped lanthanum molybdenum oxide (La2MoWO9) ceramic powders were synthesized using the complex polymerization technique. Porous ceramic pellets were obtained by thermally removing graphite, which served as a pore former. The porous pellets were then impregnated with molten eutectic lithium-sodium-potassium carbonates. The energy dispersive X-ray analysis and scanning electron microscopy (FEG-SEM) images of the external and fracture surfaces of the La2MoWO9-(Li,Na,K)2CO3 composite dual-phase membrane revealed the percolation of the carbonate mixture through the pores. Electrochemical impedance spectroscopy measurements conducted at temperatures below and above the melting point of the eutectic carbonate composition demonstrated the contributions of oxygen and carbonate ions to the ionic conductivity of the dual membrane. The electrical conductivity of the carbonate ions within the membrane was continuously monitored for over 1300 h with negligible degradation, implying that the membrane could be used for long-term monitoring of CO2 without aging effects. A comparison of FEG-SEM images taken before and after this endurance test suggested minimal fouling, indicating that the membrane could potentially replace similar zirconia- and ceria-based composite membranes.

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  • IPEN-DOC 29616

    KIM, BIANCA S.M.; AMORIM, EDUARDO P. ; SILVA, PAULO S.C. ; FIGUEIRA, RUBENS, C.L.; BRAGA, ELISABETE S.; FAVARO, DEBORAH I.T. . Vintage analysis on superficial sediments to predict future trends in metal contamination of Santos and São Vicente Estuarine System. Journal of Trace Elements and Minerals, v. 3, p. 1-8, 2023. DOI: 10.1016/j.jtemin.2023.100049

    Abstract: Due to its economic, social, and environmental importance, Santos and São Vicente Estuarine System is largely studied for almost two decades. Although many studies have been conducted, none of them tried to relate past activities to actual ones. This study provides an evaluation of the contamination on vintage superficial sediment samples investigating sediment contamination patterns over the years to help to understand future trends in metal contamination in this area. Thus, this study aims to assess levels of trace elements and rare earth elements (REEs) on samples collected in two seasonal periods of 2005 and 2006 (summer and winter). In each campaign, 16 surface samples were collected onboard R/V Veliger II, and trace elements and REEs were analyzed by neutron activation analysis. Results of metals presented similar levels over the years and it was not related to the port's activities since the levels did now increase following the total movement of containers. In addition, the enrichment of light REEs could indicate anthropogenic activities from steel plants, phosphate fertilizers, and the phosphogypsum piles. The system undergoes through many human pressures and constant monitoring over time it is important to avoid overloading the resilience capacity of the estuarine system because the expansion of port, industry, and urbanization is inevitable. From the results obtained, it was possible to conclude that SSVES undergoes more likely anthropogenic pressures from industrial activities and domestic effluents rather than port activity.

    Palavras-Chave: economic analysis; estuaries; water pollution; sediments; trace amounts; elements

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  • IPEN-DOC 29615

    RIBEIRO, I.L.F.; CARVALHO, G.L.; DIB, L.F.G.; BARBOSA, E.A.; WETTER, N.U. . Vibration amplitude mapping by stroboscopic structured light projection. Optics Communications, v. 531, p. 1-9, 2023. DOI: 10.1016/j.optcom.2022.129219

    Abstract: In this work a method to evaluate the distribution of vibration amplitudes of objects was demonstrated, combining for the first time oblique structured light projection, stroboscopic illumination and fringe evaluation. The light pattern was formed by straight and parallel fringes produced by a slightly misaligned Twyman–Green interferometer illuminated by a 40-mW, 650-nm diode laser. Stroboscopic illumination was achieved by driving the laser with a PWM signal with the same frequency than that of the vibrating object. By evaluating the fringes with phase stepping and phase unwrapping procedures, the amplitude mapping of a formica bar and circular rubber membranes was performed. By averaging the fringe position over the light pulse duration a correction ratio between the actual phase and the measured phase was obtained as a function of the pulse duty cycle, and the dependence of the fringe visibility on the duty cycle was studied. The experiments showed that relatively large amplitudes in a range from tens of millimeters up to few millimeters can be measured.

    Palavras-Chave: optical equipment; evaluation; vibrational states; mechanical vibrations

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  • IPEN-DOC 29631

    ANTUNES, PAULA C.G. ; SIQUEIRA, PAULO de T.D. ; SHORTO, JULIAN M.B. ; YORIYAZ, HELIO . A versatile physical phantom design and construction for I-125 dose measurements and dose-to-medium determination. Brachytherapy, v. 22, n. 1, p. 80-92, 2023. DOI: 10.1016/j.brachy.2022.10.005

    Abstract: PURPOSE: In this paper we present a phantom designed to provide conditions to generate set of “true” independent reference data as requested by TG-186, and mitigating the scarcity of experimental studies on brachytherapy validation. It was used to perform accurate experimental measurements of dose of 125I brachytherapy seeds using LiF dosimeters, with the objective of experimentally validating Monte Carlo (MC) calculations with model-based dose calculation algorithm (MBDCA). In addition, this work intends to evaluate a methodology to convert the experimental values from LiF into dose in the medium. METHODS AND MATERIALS: The proposed PMMA physical phantom features cavities to insert a LiF dosimeter and a 125I seed, adjusted in different configurations with variable thickness. Monte Carlo calculations performed with MCNP6.2 code were used to score the absorbed dose in the LiF and the dose conversion parameters. A sensitivity analysis was done to verify the source of possible uncertainties and quantify their impact on the results. RESULTS: The proposed phantom and experimental procedure developed in this work provided precise dose data within 5.68% uncertainty (k = 1). The achieved precision made it possible to convert the LiF responses into absorbed dose to medium and to validate the dose conversion factor methodology. CONCLUSIONS: The proposed phantom is simple both in design and as in its composition, thus achieving the demanded precision in dose evaluations due to its easy reproducibility of experimental setup. The results derived from the phantom measurements support the dose conversion methodology. The phantom and the experimental procedure developed here can be applied for other materials and radiation sources.

    Palavras-Chave: biological models; phantoms; brachytherapy; iodine 125; seeds; lithium fluorides; monte carlo method

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  • IPEN-DOC 29943

    SOUZA, CATARINA da S. ; ZAMBONI, CIBELE B. ; MOURA, LARISSA A.S. ; METAIRON, SABRINA; SILVA, DALTON G.N. da . Uso de mini-espectrômetro de fluorescência de raios X como alternativa para a prática clínica de dialisados / Use of X-ray fluorescence mini-spectrometer as an alternative for clinical practice of dialysates. Revista Remecs, v. 8, n. 14, p. 52-60, 2023. DOI: 10.24281/rremecs2023.8.14.52-60

    Abstract: Neste estudo, o uso de equipamento compacto e portátil, baseado na tecnologia de Fluorescência de Raios X, foi empregado para execução de análises bioquímicas (dosagens de íons) em microamostras de fluidos corpóreos depositadas em papel. Foi realizada a análise simultânea de íons de relevância clínica e nutricional (Ca, Cl, Fe, K, P e S), em sangue total de pacientes com insuficiência renal crônica (IRC) submetidos a tratamento dialítico. Durante a investigação as concentrações obtidas em sangue total levaram a resultados que corroboram com o quadro clínico obtido pelas análises convencionais. Com os dados do presente foi possível elaborar uma discussão sobre a viabilidade de uso deste equipamento para a realização desses exames bioquímicos em Unidades Básicas de Saúde Fluviais (UBSF), gerando melhorias na qualidade de vida de populações ribeirinhas, bem como no âmbito econômico em função de sua aplicabilidade com menor custo. Descritores: Íons, Sangue, Análise Clínica.

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  • IPEN-DOC 29789

    BATISTA, JOAO V.B.; TROMBINI, HENRIQUE; OTSUKA, ANDRE; SILVEIRA, IURY S. ; CALDAS, LINDA V.E. ; SOUZA, ANTONIO O. de; SOUZA, ADELMO S.; SANTOS, JORGE L.O.; COELHO, VINICIUS; LIMA, HEVESON. Unlocking the effect of Li and Ce ions on the thermoluminescence and optically stimulated luminescence signals of the MgB4O7 compound. Dalton Transactions, v. 52, n. 19, p. 6407–6419, 2023. DOI: 10.1039/d3dt00485f

    Abstract: Magnesium tetraborate (MgB4O7) is an example of a material that has attracted the attention of researchers in the field of ionising radiation dosimetry. Several challenges are present in order to achieve considerable advances in luminescence dosimetry. The incorporation of efficient dopants in the host matrix has been an experimentally useful but limited strategy. The lack of specific information about the introduced defects as well as their connection with the trapping and recombination processes associated with light emission may be quoted as challenging examples. Here, we demonstrate the influence of lithium incorporation on Optically Stimulated Luminescence (OSL)/Thermoluminescence (TL) signal modification/suppression of MgB4O7 by combining experimental and computational procedures. Li substitution into the Mg site leads to a signal suppression due to the probable quenching of the Fs and Fs + centres in MgO and the formation of O’’i , drastically reducing the possibility of MgO anti-Schottky defect formation in MgB4O7. When using Li-co-doped MgB4O7:Ce3+, the Li ions act as a charge balancer, facilitating the entry of Ce ions into the interstitial pores and making possible a positive synergistic effect on the luminescence and dosimetric properties. These findings provide new insights into designing more efficient dosimeters by tuning dopants.

    Palavras-Chave: lithium; cerium; magnesium; luminescence; thermoluminescent dosemeters

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  • IPEN-DOC 29720

    NAVILLE, WILLIAM ; MAGNABOSCO, RODRIGO; COSTA, ISOLDA . Uniaxial plastic strain effect on the corrosion-fatigue resistance of ISO 5832-1 stainless steel biomaterial. International Journal of Fatigue, v. 173, p. 1-10, 2023. DOI: 10.1016/j.ijfatigue.2023.107701

    Abstract: Orthopaedic implants are used for fracture stabilization or orthopaedic reconstruction. During implantation and even in the implant accommodation process, there may be plastic strain and induction of residual stresses. This information creates a test procedure involving pre-strain, pre-conditioning in the corrosive environment and corrosion-fatigue tests. Two solutions were used, PBS (phosphate-buffered saline, neutral pH, recommended for corrosion evaluation tests) and SHA (saline solution with hydrogen peroxide and albumin pH 3.0). The results showed that, differently from PBS, SHA promoted localized corrosion, reducing fatigue resistance in all tested conditions. In addition, plastic pre-strain influenced the failure process.

    Palavras-Chave: corrosion fatigue; albumins; stainless steels; hydrogen peroxide; environmental effects

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  • IPEN-DOC 30036

    MUNOZ, PATRICIO; ILAVSKY, JAN; NEWVILLE, MATTHEW; WETTER, NIKLAUS U. ; LOURENÇO, RAFAEL A.; ANDRADE, MARCELO B. de; MARTINS, TEREZA S.; DIPOLD, JESSICA ; FREITAS, ANDERSON Z. ; SILVA, LUIS C.C. da; OLIVEIRA, CRISTIANO L.P.. (U)SAXS characterization of porous microstructure of chert: insights into organic matter preservation. Journal of Applied Crystallography, v. 56, Part: 6, p. 1692-1706, 2023. DOI: 10.1107/S1600576723008889

    Abstract: This study characterizes the microstructure and mineralogy of 132 (ODP sample), 1000 and 1880 million-year-old chert samples. By using ultra-smallangle X-ray scattering (USAXS), wide-angle X-ray scattering and other techniques, the preservation of organic matter (OM) in these samples is studied. The scarce microstructural data reported on chert contrast with many studies addressing porosity evolution in other sedimentary rocks. The aim of this work is to solve the distribution of OM and silica in chert by characterizing samples before and after combustion to pinpoint the OM distribution inside the porous silica matrix. The samples are predominantly composed of alpha quartz and show increasing crystallite sizes up to 33 5 nm (1 standard deviation or SD). In older samples, low water abundances (0.03%) suggest progressive dehydration. (U)SAXS data reveal a porous matrix that evolves over geological time, including, from younger to older samples, (1) a decreasing pore volume down to 1%, (2) greater pore sizes hosting OM, (3) decreasing specific surface area values from younger (9.3 0.1 m2 g 1 ) to older samples (0.63 0.07 m2 g 1 , 1 SD) and (4) a lower background intensity correlated to decreasing hydrogen abundances. The pore-volume distributions (PVDs) show that pores ranging from 4 to 100 nm accumulate the greater volume fraction of OM. Raman data show aromatic organic clusters up to 20 nm in older samples. Raman and PVD data suggest that OM is located mostly in mesopores. Observed structural changes, silica–OM interactions and the hydrophobicity of the OM could explain the OM preservation in chert.

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  • IPEN-DOC 29879

    MORAES, LETICIA P.R. ; MACHADO, MARINA. ; RODRIGUES, LAYS N. ; SUN, ZIQI; MARANI, DEBORA; FONSECA, FABIO C. . Two-dimensional gadolinium-doped ceria nanosheets for low temperature sintering of solid oxide fuel cells barrier layer. Journal of Alloys and Compounds, v. 967, p. 1-9, 2023. DOI: 0.1016/j.jallcom.2023.171766

    Abstract: A novel method for bottom-up synthesis of two-dimensional (2D) gadolinium-doped cerium oxide (CGO) nanosheets is developed and demonstrated as an efficient precursor for interdiffusion barrier layer deposition in solid oxide fuel cells. The CGO is the standard material used as an interlayer in intermediate-temperature solid oxide fuel cells to avoid undesirable reactions between lanthanum strontium cobalt ferrite (LSCF) cathode and yttria-stabilized zirconia (YSZ) electrolyte materials. Herein, the shape-control of the 2D CGO by a low-cost wetchemical method allowing for the fabrication of fully dense barrier layer of CGO is reported. The high surface coverage promoted by the 2D CGO nanosheets resulted in a thin (~ 1 µm) and dense interdiffusion barrier layer sintered at 1150 ◦C preventing the undesirable reaction between oxide ion conducting phases occurring at higher temperatures. The electrochemical properties of solid oxide fuel cells confirmed the CGO nanosheet as an efficient layer for preventing the formation of resistive phases at the electrolyte/cathode interface.

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  • IPEN-DOC 29950

    PIERETTI, EURICO F. ; CORREA, OLANDIR V. ; NEVES, MAURICIO D.M. das ; ANTUNES, RENATO A.; PILLIS, MARINA F. . Tribology analysis on anodized aluminum surfaces for biomedical purposes. Brazilian Journal of Motor Behavior, v. 17, n. 2, p. 196-197, 2023.

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  • IPEN-DOC 29874

    ALBANIT, LETICIA F.; BEVERARI, ISABELLA; CESAR-RIBEIRO, CAIO; GIMILIANI, GIOVANA T. ; ABESSA, DENIS M. de S.. Toxicity of glitter to marine organisms: a baseline study with embryos of the sand-dollar Mellita quinquiesperforata. International Aquatic Research, v. 15, n. 2, p. 181-189, 2023. DOI: 10.22034/IAR.2023.1973104.1359

    Abstract: This study aimed to determine the toxicity of glitter particles of two colors (green and white) on the embryos of the sand dollar Mellita quinquiesperforata. Toxicity tests were performed using both green- and white-glitter particles. Adult sand dollar individuals were collected and gametes were obtained by osmotic induction. Each glitter was tested in five test solutions: 0.01, 0.1, 1, 10 and 100% (= mg L-1). The results were analyzed by the Wilcoxon–Mann–Whitney test, allowing the determination of the lowest observed effect concentration (LOEC) and the no observed effect concentration (NOEC). The LOECs calculated for the green glitter dispersions were 0.01 % (P < 0.05) in the first two tests, and 100% in the third test. The LOECs for the white-glitter dispersions ranged from 0.01 % to 0.1 %. Our results demonstrate that glitters of both colors are capable of affecting the embryonic development of M. quinquiesperforata.

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  • IPEN-DOC 29719

    DIMMER, JESICA A.; CABRAL, FERNANDA V.; MONTOYA, SUSANA C.N.; RIBEIRO, MARTHA S. . Towards effective natural anthraquinones to mediate antimicrobial photodynamic therapy of cutaneous leishmaniasis. Photodiagnosis and Photodynamic Therapy, v. 42, p. 1-6, 2023. DOI: 10.1016/j.pdpdt.2023.103525

    Abstract: Background: Cutaneous leishmaniasis (CL) is an important tropical neglected disease with broad geographical dispersion. The lack of effective drugs has raised an urgent need to improve CL treatment, and antimicrobial photodynamic therapy (APDT) has been investigated as a new strategy to face it with positive outcomes. Natural compounds have emerged as promising photosensitizers (PSs), but their use in vivo remains unexplored. Purpose: In this work, we investigated the potential of three natural anthraquinones (AQs) on CL induced by Leishmania amazonensis in BALB/c mice. Study Design/Methods: : Animals were infected and randomly divided into four groups: CG (control, non-treated group), G5ClSor-gL (treated with 5-chlorosoranjidiol and green LED, 520±10 nm), GSor-bL and GBisor-bL (treated with soranjidiol and bisoranjidiol, respectively, exposed to violet-blue LED, 410±10 nm). All AQs were assayed at 10 μM and LEDs delivered a radiant exposure of 45 J/cm2 with an irradiance of 50 mW/cm2 . We assessed the parasite burden in real time for three consecutive days. Lesion evolution and pain score were assessed over 3 weeks after a single APDT session. Results: G5ClSor-gL was able to sustain low levels of parasite burden over time. Besides, GSor-bL showed a smaller lesion area than the control group, inhibiting the disease progression. Conclusion: Taken together, our data demonstrate that monoAQs are promising compounds for pursuing the best protocol for treating CL and helping to face this serious health problem. Studies involving host-pathogen interaction as well as monoAQ-mediated PDT immune response are also encouraged.

    Palavras-Chave: skin diseases; parasites; protozoa; light emitting diodes; luminescence; pain

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  • IPEN-DOC 29678

    GROSSI, DANIELLE; LAZAR, DOLORES R.R. ; DEL LAMA, ELIANE A.; USSUI, VALTER . Titania-silica composite with photocatalytic properties and its application on Brazilian granite and sandstone. International Journal of Architectural Heritage, v. 17, n. 5, p. 770-787, 2023. DOI: 10.1080/15583058.2021.1969483

    Abstract: The aim of the study described in this article was to evaluate a product containing titania (titanium dioxide, TiO2) applied on stones — particularly two types used at Brazilian stone-built heritage sites — that have been exposed to weathering and anthropogenic activities. This product was prepared by producing a suspension of TiO2 at two concentrations (1% and 4% w/v) with tetraethyl orthosilicate (TEOS) in the presence of n-octylamine as surfactant. The characteristics of the TiO2 were then observed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface-area measurements, particle-size distribution analysis (CILAS) and X-ray diffraction. After applying the TiO2-TEOS composite, the stones were examined for contact angle, spectrophotometry, sorptivity, thermal shock resistance, and UV-radiation resistance. The product proved ineffective on Itararé sandstone, mainly due to its mineralogical components, as the product does not adhere to quartz. When applied on Itaquera granite, the 1% TiO2 (w/v) concentration proved to be an appropriate treatment, as it demonstrated better thermal shock resistance, photocatalytic activity, porosity maintenance, and global colour when compared to the 4% concentration.

    Palavras-Chave: architecture; cultural resources; photocatalysis; sandstones; composite materials; titanium oxides

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  • IPEN-DOC 30173

    MOYA, MURILO T.M.; ARAUJO, LEANDRO G. de ; LOPES, FERNANDO S.; TEIXEIRA, ANTONIO C.S.C.. TiO2 P25 and Kronos vlp 7000 materials activated by simulated solar light for atrazine degradation. International Journal of Chemical Reactor Engineering, v. 21, n. 10, p. 1211-1223, 2023. DOI: 10.1515/ijcre-2022-0186

    Abstract: Photocatalysis-based technologies have been proposed for the treatment of wastewater containing atrazine (ATZ), a persistent and recalcitrant pollutant. This study aims to evaluate and compare the efficiency of TiO2 P25 and TiO2 modified with carbon (C–TiO2 Kronos vlp 7000) in the photocatalytic degradation of ATZ in aqueous systems. The experiments were performed in a tubular photochemical reactor equipped with a compound parabolic collector (CPC) irradiated by simulated solar light. The materials were characterized by X-ray diffraction, infrared spectroscopy, BET specific surface area, and diffuse reflectance spectroscopy. For TiO2 P25, ATZ removals varied in the range 86–100 % after 120 min of irradiation, although the total organic carbon (TOC) analyses indicated that no significant ATZ mineralization occurred (<20 %). C–TiO2 Kronos vlp 7000, on the other hand, was not able to completely remove ATZ after 120 min of irradiation. In this case, pesticide removals were 37–45 % over 120 min, while C–TiO2 performed better with regard to ATZ mineralization, with 38 % TOC removal. Given the low mineralization of atrazine, the intermediate compounds formed were identified for each photocatalytic material.

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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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