INSTITUTO DE PESQUISAS ENERGÉTICAS E NUCLEARES
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Navegação Periódicos - Artigos por Agências de fomento "Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)"

Navegação Periódicos - Artigos por Agências de fomento "Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)"

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  • IPEN-DOC 28812

    MOREIRA, GREGORI de A. ; OLIVEIRA, AMAURI P. de; CODATO, GEORGIA; SANCHEZ, MACIEL P.; TITO, JANET V.; SILVA, LEONARDO A.H. e; SILVEIRA, LUCAS C. da; SILVA, JONATAN J. da ; LOPES, FABIO J. da S. ; LANDULFO, EDUARDO . Assessing spatial variation of PBL height and aerosol layer aloft in São Paulo Megacity using simultaneously two lidar during winter 2019. Atmosphere, v. 13, n. 4, p. 1-16, 2022. DOI: 10.3390/atmos13040611

    Abstract: This work presents the use of two elastic lidar systems to assess the horizontal variation of the PBL height (PBLH) and aerosol layer aloft in the São Paulo Megacity. These two lidars performed simultaneous measurements 10.7 km apart in a highly urbanized and relatively flat area of São Paulo for two winter months of 2019. The results showed that the PBLH differences display diurnal variation that depends on the PBL during daytime growth phases. Cloud and sea breeze effects control most of PBLH variation. In the absence of cloud and sea breeze, the maximum difference (~300 m) occurs in the rapid development stage and is due to topographic effects. When the PBL approaches its maximum daily value, it tends to level off with respect to the topography. In addition, it was presented a method that combines elastic lidar (to detect an aerosol layer) and satellite data (to classify such a layer from Aerosol Optical Depth (AOD) and Aerosol Index (AI) information) for the detection of biomass burning events. This methodology demonstrated that the variations caused by Biomass Burning in AOD and AI enable both the detection of aerosol plumes originating from biomass burning and the identification of their origin.

    Palavras-Chave: boundary layers; earth atmosphere; biomass; burns; urban areas; optical radar

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  • IPEN-DOC 28871

    CASTRO, PEDRO A.A. de ; DIAS, DERLY A. ; DEL-VALLE, MATHEUS ; VELOSO, MARCELO N. ; SOMESSARI, ELIZABETH S.R. ; ZEZELL, DENISE M. . Assessment of bone dose response using ATR-FTIR spectroscopy: a potential method for biodosimetry. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, v. 273, p. 1-7, 2022. DOI: 10.1016/j.saa.2022.120900

    Abstract: The health care application of ionizing radiation has expanded worldwide during the last several decades. While the health impacts of ionizing radiation improved patient care, inaccurate handling of radiation technology is more prone to potential health risks. Therefore, the present study characterizes the bone dose response using bovine femurs from a slaughterhouse. The gamma irradiation was designed into low-doses (0.002, 0.004 and 0.007 kGy) and high-doses (1, 10, 15, 25, 35, 50 and 60 kGy), all samples received independent doses. The combination of FTIR spectroscopy and PLS-DA allows the detection of differences in the control group and the ionizing dose, as well as distinguishing between high and low radiation doses. In this way, our findings contribute to future studies of the dose response to track ionizing radiation effects on biological systems.

    Palavras-Chave: ionizing radiations; radiation doses; dosimetry; skeleton; biological dosemeters; fourier transformation; infrared radiation

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  • IPEN-DOC 29087

    GRANDIZOLI, D.R.P.; RENZO, A.L.M.; SAKAE, L.O.; LOPES, R.M.; ZEZELL, D.M. ; ARANHA, A.C.C.; SCARAMUCCI, T.. Assessment of the ability of desensitizing and conventional mouth rinses to promote dentin tubule occlusion. Operative Dentistry, v. 47, n. 5, p. 549-561, 2022. DOI: 10.2341/21-043-L

    Abstract: This study aimed to evaluate the effect of desensitizing and conventional mouth rinses on dentin tubule occlusion. Dentin hypersensitivity was simulated by EDTA application for five minutes. The specimens were randomly allocated into the following groups: desensitizing mouth rinses (Colgate Sensitive, Elmex Sensitive Professional, Listerine Advanced Defense Sensitive, Sensodyne Cool Mint); conventional mouth rinses (Colgate Plax, Elmex Caries Protection, Listerine Anticaries, Sensodyne Pronamel); a negative control (C−: distilled water); and Clinpro XT Varnish was the positive control (C+). Subsequently, the specimens were submitted to an erosive or abrasive challenge (performed separately) and to an erosive/abrasive cycling for five days (n=10 for each challenge). After treatment, challenges, and cycling, the specimens were analyzed in an environmental scanning electron microscope to verify the number of open dentin tubules (ODTs), counted by using Image J software (National Institutes of Health, Bethesda, MD, USA). Data were analyzed by the Kruskal-Wallis, Friedman and Dunn tests, with Bonferroni correction (α=0.05). Groups did not differ at baseline (p>0.05). At the post-treatment, erosion and abrasion stages, C+ was the only group that showed a reduction in ODTs compared to C−(p<0.05). In the other groups, numbers did not differ significantly from C− (p>0.05). After cycling, none of the groups exhibited significant reduction in ODTs other than C− (p>0.05); however, C+, Listerine Anticaries, and Colgate Plax had a lower number of ODTs than Listerine Sensitive and Sensodyne Pronamel. No mouth rinse was able to promote significant occlusion of the dentin tubules after treatment and the challenges. C+ was the only product that effectively promoted tubular occlusion, but this effect did not withstand several erosive and abrasive challenges.

    Palavras-Chave: oral cavity; dentistry; dentin; tubules; sensitivity

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  • IPEN-DOC 28066

    DIAS-MORAES, MARCIA C. ; CASTRO, PEDRO A.A. ; PEREIRA, DAISA L. ; ANA, PATRICIA A.; FREITAS, ANDERSON Z. ; ZEZELL, DENISE M. . Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy. PLoS One, v. 16, n. 7, p. 1-14, 2021. DOI: 10.1371/journal.pone.0254217

    Abstract: Objective This in vitro study characterized and monitored, by Optical Coherence Tomography (OCT) and Fourier Transformed Infrared Spectroscopy (FTIR), the effects of the association of acidulated phosphate fluoride gel (APF-gel) and Nd:YAG (neodymiun:yttrium-aluminum-garnet) laser, as sequencial treatments, in the prevention of incipient enamel caries lesions. Methods 120 human enamel samples were randomized into 3 groups (n = 40): APF-gel (1.23% F-, 4 min.); Laser+APF (Nd:YAG laser irradiation—0.6W, 84.9J/cm2, 10Hz, followed by APF-gel); and APF+Laser (APF-gel followed by laser irradiation). The samples were subjected to a 15-day pH-cycling, evaluated by OCT (quantification of optical attenuation coefficient–OAC) and FTIR (analysis of carbonate and phosphate content) before treatments, after treatments, and on the 5th, 10th and 15th days of pH-cycling. The statistical analysis was performed (α = 5%). Results The Optical Attenuation Coefficient (OAC) assessed by OCT increases with the progression of demineralization, and the Laser+APF presented the highest values of OAC in 10th and 15th days of pH-cycling. Nd:YAG decreased the carbonate content after treatment regardless of the application order of the APF-gel, while APF-gel did not interfere in the composition of enamel. The carbonate content was also changed in the first 5 days of the pH-cycling in all groups. Conclusion Nd:YAG laser irradiation before or after the application of APF-gel did not influence the appearance of incipient caries lesions, showing no synergistic effect. Regardless of the application order of the APF-gel, laser irradiation reduces the carbonate content of the enamel, which also changes during the demineralization process. However, irradiation before the application of APF-gel increased the speed of progression of the lesions, which positively impacts public health as it can prevent caries disease, even in high risk individuals. OCT and FTIR are suitable for assessing this effect.

    Palavras-Chave: neodymium lasers; dentistry; enamels; laser radiation; fluorides

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  • IPEN-DOC 27792

    MAXIMIANO, VINICIUS; MACHADO, ALANA C.; LOPES, RAQUEL M.; RABELO, FERNANDA E.M.; GAROFALO, STEPHANIE A.; ZEZELL, DENISE M. ; ARANHA, ANA C.C.; SCARAMUCCI, TAIS. Association of Nd:YAG laser and calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion. Journal of Applied Oral Science, v. 29, p. 1-11, 2021. DOI: 10.1590/1678-7757-2020-0736

    Abstract: Objective: To evaluate the efficacy of Nd:YAG laser associated with calcium-phosphate desensitizing pastes on dentin permeability and tubule occlusion after erosive/abrasive challenges. Methodology: Dentin specimens were exposed to 17% ethylene diamine tetra-acetic acid (EDTA) solution for 5 min and randomly allocated into five groups: G1, control (no treatment); G2, Nd:YAG laser (1 W, 10 Hz, 100 mJ, 85 J/cm2); G3, Laser + TeethmateTM Desensitizer; G4, Laser + Desensibilize Nano P; and G5, Laser+Nupro®. Specimens underwent a 5-day erosion-abrasion cycling. Hydraulic conductance was measured post-EDTA, post-treatment, and post-cycling. Post-treatment and post-cycling permeability (%Lp) was calculated based on post-EDTA measurements, considered 100%. Open dentin tubules (ODT) were calculated at the abovementioned experimental moments using scanning electron microscopy and ImageJ software (n=10). Data were analyzed using two-way repeated measures ANOVA and Tukey’s test (α=0.05). Results: G1 presented the highest %Lp post-treatment of all groups (p<0.05), without significantly differences among them. At post-cycling, %Lp significantly decreased in G1, showed no significant differences from post-treatment in G3 and G4, and increased in G2 and G5, without significant differences from G1 (p>0.05). We found no significant differences in ODT among groups (p>0.05) post-EDTA. At post-treatment, treated groups did not differ from each other, but presented lower ODT than G1 (p<0.001). As for post-cycling, we verified no differences among groups (p>0.05), although ODT was significantly lower for all groups when compared to post-EDTA values (p<0.001). Conclusion: All treatments effectively reduced dentin permeability and promoted tubule occlusion after application. Combining Nd:YAG laser with calcium-phosphate pastes did not improve the laser effect. After erosive-abrasive challenges, treatments presented no differences when compared to the control.

    Palavras-Chave: dentistry; neodymium lasers; calcium phosphates; sensitivity analysis; permeability

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  • IPEN-DOC 27171

    FONTES, E.H. ; NANDENHA, J. ; SOUZA, R.F.B. de ; ANTONIO, F.C.T.; HOMEM-DE-MELLO, P.; NETO, A.O. . Au core stabilizes CO adsorption onto Pd leading to CO2 production. Materials Today Advances, v. 6, p. 1-9, 2020. DOI: 10.1016/j.mtadv.2020.100070

    Abstract: Au core and Pd shell supported on carbon structure Au@Pd/C can cleave the CeC bond of ethanol molecules leading to the production of a relatively high amount of CO2 when compared with Pd/C electrocatalyst as the attenuated total reflectance - Fourier transform infrared (ATR-FTIR) experiment shows. Density functional theory (DFT) calculations showed that this could be explained by the oxidation of CO species adsorbed into Pd sites that has a modified electronic structure compared with Pd/C. In terms of DFT analysis, the highest thermodynamical stability of CO in Pd shell with Au core atoms, when compared with Pd/C is because of the increase of virtual orbital states near Fermi level that can be occupied by valence electrons of CO molecule. The d-band center shift is experimentally verified using the valence band X-ray photoelectron spectroscopy and theoretically predicted by the Generalized Koopmans’ Theorem. Besides that, Au@Pd/C electrocatalyst has a better electrochemical activity when compared with Pd/C.

    Palavras-Chave: ethanol; oxidation; calculation methods; density; nanoparticles; adsorption; carbon dioxide; density functional method

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  • IPEN-DOC 23195

    SANTOS, W.S. ; NEVES, L.P.; PERINI, A.P.; BELINATO, W.; MAIA, A.F.; CALDAS, L.V.E. . Avaliação das exposições dos envolvidos em procedimentos intervencionistas usando método Monte Carlo. Brazilian Journal of Radiation Sciences, v. 5, n. 1, p. 01-06, 2017.

    Abstract: Neste estudo apresenta-se um modelo computacional de exposição de um paciente, médico cardiologista e de uma enfermeira em um cenário típico de procedimentos intervencionistas cardíacos. Neste caso, foi calculado um conjunto de coeficientes de conversão (CC) para dose efetiva (E) em termos do produto kerma-área (PKA) para os indivíduos envolvidos, utilizando sete espectros energéticos diferentes e oito projeções de feixe. Também foi calculado o CC para dose de entrada na pele (DEP) do paciente normalizado pelo PKA. Todos os indivíduos foram representados por simuladores antropomórficos computacionais incorporados em um código de transporte de radiação baseado em simulação de Monte Carlo.

    Palavras-Chave: air; conversion; dosimetry; kerma; monte carlo method; occupational exposure; patients; phantoms; radiation doses; radiation protection; radiology; radiological personnel

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  • IPEN-DOC 20387

    QUEIROZ, FERNANDA M. ; ELSNER, CECILIA I.; TOMACHUK, CELIA R. ; DI SARLI, ALEJANDRO R.; COSTA, ISOLDA . Avaliação do sistema Zn-Cr III-revestimento orgânico por espectroscopia de impedância eletroquímica / Evaluation of Zn-Cr III-organic coating by electrochemical impedance spectroscopy. Tecnologia em Metalurgia, Materiais e Mineração, v. 10, n. 1, p. 8-15, 2013. DOI: 10.4322/tmm.2013.002

    Abstract: O controle da corrosão de aço eletrogalvanizado empregando soluções à base de sais de Cr VI é amplamente conhecido e estudado. No entanto, pesquisadores vêm buscando alternativas para substituir estes sais já que diretrizes ambientais e industriais exigem que sejam banidos. Os revestimentos de conversão à base de Cr III têm mostrado um desempenho compatível aos baseados em Cr VI. Neste trabalho são utilizadas medidas de espectroscopia de impedância eletroquímica (EIE) em NaCl 0,05 mol/L e em Na2SO4 0,1 mol/L, durante o tempo de imersão, para avaliar a resistência à corrosão de aço eletrogalvanizado revestido com tratamento à base de Cr III e pintado com três diferentes revestimentos orgânicos. Os revestimentos orgânicos sãocaracterizados por sua adesão. Os resultados mostram um comportamento semelhante para os três revestimentos e, apesar de uma segunda constante de tempo ter sido observada nos ajustes de EIE, os valores de R2 indicam uma baixa velocidade de corrosão. O sistema Zn – Cr III – revestimento orgânico é compatível ao sistema Zn – Cr VI – revestimento orgânico, para o período de imersão considerado.

    Palavras-Chave: electrochemical coating; impedance; spectroscopy; chromium compounds; steels; organic compounds; coatings

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  • IPEN-DOC 23196

    SANTOS, S.C. ; RODRIGUES JUNIOR, O. ; CAMPOS, L.L. . Bio-prototyping of europium-yttria based rods for radiation dosimetry. Materials Chemistry and Physics, v. 199, p. 557-566, 2017. DOI: 10.1016/j.matchemphys.2017.07.063

    Abstract: The application of solid state dosimeters in radiation protection has grown significantly as consequence of advances in the development of dosimetric materials using rare earths. The conception of new dosimetric materials concerns synthesis methods, which control the evolution of material structure, including further processing steps as, shaping, drying, and sintering. The present study reports a full bio-prototyping approach to produce europium doped yttria rods with potential application in radiation dosimetry. Ceramic particles synthesized by hydrothermal route were characterized by Photon Correlation Spectroscopy (PCS), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The effect of europium on promoting electronic defects in yttria host was evaluated by Electron Paramagnetic Resonance (EPR). Low pressure hydrothermal synthesis led to formation of rounded particles with mean diameter of 410 nm. Aqueous suspensions with 20 vol% of particles prepared at pH 10, and 0.2 wt% binder exhibited apparent viscosity of 213 mPa s, being suitable for bio-prototyping of rods. Sintering of shaped samples at 1600 degrees C for 4 h provided formation of dense ceramic rods. Europium-yttria rods containing 5 at.% Eu exhibited the most intense EPR response.

    Palavras-Chave: biotechnology; europium; rare earths; dosimetry; yttrium; ceramics; processing

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  • IPEN-DOC 28321

    BORGES, ROGER; KAI, KAREN C.; LIMA, CASSIO A. ; ZEZELL, DENISE M. ; ARAUJO, DANIELE R. de; MARCHI, JULIANA. Bioactive glass/poloxamer 407 hydrogel composite as a drug delivery system: The interplay between glass dissolution and drug release kinetics. Colloids and Surfaces B: Biointerfaces, v. 206, p. 1-11, 2021. DOI: 10.1016/j.colsurfb.2021.111934

    Abstract: Since patients suffer pain in the post-surgery of bone repair interventions, bioactive glass/hydrogel drug delivery systems containing local anesthetics, such as ropivacaine, could improve patient life quality by combining bone regeneration with anesthetics. However, poloxamer-based hydrogel properties are sensitive to ions, temperature, and water contents and could be structurally influenced by the ionic dissolution products from bioactive glasses of different compositions. Therefore, this study evaluated the interplay between bioactive glass dissolution kinetics and poloxamer 407 properties, establishing a correlation between changes in the hydrogel and drug release kinetics. Three glass compositions were produced, yielding Ca-rich, Na-rich, and an intermediate glass composition. The influence of Ca/Na ratios on the glass structure and dissolution was investigated. Further, the glasses and ropivacaine were incorporated in the poloxamer hydrogel, and the self-assembly ability of poloxamer, the degradation rate, and the drug release kinetics of the composites were evaluated. The results suggested that glass connectivity affected the early-stage of glass dissolution, while sodium mobility influenced the long-term. The dissolution products from the glasses interact with the supramolecular structure of the poloxamer, causing structural changes responsible for hydrogel degradation. Consequently, by changing the Ca/Na ratio in the glasses, it is possible to modulate glass dissolution that, in turn, influences the ropivacaine release. Thus, we propose that the Ca/Na ratio in quaternary bioactive glasses can be used to modulate drug-delivery properties from systems based on bioactive glasses and poloxamer 407.

    Palavras-Chave: drugs; delivery; hydrogels; bone tissues; kinetics; anesthetics

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  • IPEN-DOC 25112

    MARIANO, DOUGLAS O.C.; MESSIAS, MARCELA Di G. ; PREZOTTO-NETO, JOSE P. ; SPENCER, PATRICK J. ; PIMENTA, DANIEL C.. Biochemical analyses of proteins from duttaphrynus melanostictus (Bufo melanostictus) skin secretion: soluble protein retrieval from a viscous matrix by ion-exchange batch sample preparation. Protein Journal, v. 37, n. 4, p. 380-389, 2018. DOI: 10.1007/s10930-018-9780-z

    Abstract: A crucial step in scientific analysis can be sample preparation, and its importance increases in the same rate as the sensitivity of the following employed/desired analytical technique does. The need to analyze complex, viscous matrices is not new, and diverse approaches have been employed, with different success rates depending on the intended molecules. Solid-phase extraction, for example, has been successfully used in sample preparation for organic molecules and peptides. However, due to the usual methodological conditions, biologically active proteins are not successfully retrieved by this technique, resulting in a low rate of protein identification reported for the viscous amphibian skin secretion. Here we describe an ion-exchange batch processing sample preparation technique that allows viscous or adhesive materials (as some amphibian skin secretions) to be further processed by classical liquid chromatography approaches. According to our protocol, samples were allowed to equilibrate with a specific resin that was washed with appropriated buffers in order to yield the soluble protein fraction. In order to show the efficiency of our methodology, we have compared our results to classically prepared skin secretion, i.e., by means of filtration and centrifugation. After batch sample preparation, we were able to obtain reproductive resolved protein chromatographic profiles, as revealed by SDS-PAGE, and retrieve some biological activities, namely, hydrolases belonging to serine peptidase family. Not only that, but also the unbound fraction was rich in low molecular mass molecules, such as alkaloids and steroids, making this sample preparation technique also suitable for the enrichment of such molecules.

    Palavras-Chave: chromatography; ion exchange chromatography; animal tissues; secretion; skin; sample preparation; viscosity; amphibians; hydrolases

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  • IPEN-DOC 27156

    AZEVEDO, LUCIANA C. de ; ROVANI, SUZIMARA ; SANTOS, JONNATAN J.; DIAS, DJALMA B. ; NASCIMENTO, SANDI S.; OLIVEIRA, FABIO F.; SILVA, LEONARDO G.A. ; FUNGARO, DENISE A. . Biodegradable films derived from corn and potato starch and study of the effect of silicate extracted from sugarcane waste ash. ACS Applied Polymer Materials, v. 2, n. 6, p. 2160-2169, 2020. DOI: 10.1021/acsapm.0c00124

    Abstract: The growing concern with the amount of plastic materials found in the oceans makes it necessary to develop biodegradable materials that have low toxicity to marine animals and humans, but at the same time are resistant to the actions of microorganisms such as fungi or bacteria. On the other hand, agricultural waste rich in inorganic materials (such as silica) is often discarded, while it could be reused as a source of raw material. Considering these points, sodium silicate solution extracted from sugarcane waste ash was utilized to prepare biodegradable bioplastics based on corn starch and potato starch. The starch-based bioplastics were produced by casting and characterized by several physical-chemical techniques evaluating tensile strength, elongation at break, color analyses, transparency, opacity, moisture, and biodegradation assay. Bioplastics prepared with corn starch presented better physical, mechanical, and thermal properties and optical quality than bioplastics based on potato starch. The samples called CS3 and PS3, with 5.0% glycerol, were the most resistant to tensile strengths of 0.73 and 0.36 MPa, respectively. On the other hand, the highest elongation at break values were found for the samples with 7.5% glycerol (CS9, 52.90% and PS9, 49.33%). Corn starch-based bioplastics were more thermally resistant (CS3, 152.86 °C and CS9, 135.20 °C) when compared to potato starch-based bioplastics (PS3, 140.39 °C and PS9, 127.57 °C). In general, the addition of sodium silicate solution improved the mechanical and thermal properties of both types of bioplastics. The potato starch-based bioplastics were biodegraded in 5 days, while those made from corn starch took almost 40 days. The inclusion of sodium silicate inhibited fungal growth for both corn starch and potato starch bioplastics. The results suggest that sodium silicate solution obtained from renewable sources can be incorporated into starch-based bioplastics for production of biodegradable packaging with antifungal activity.

    Palavras-Chave: biodegradation; agriculture; sugar cane; agricultural wastes; bagasse; chemical composition; ashes; maize; potatoes; starch; plastics; sustainability; sodium silicates; environment; polymers

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  • IPEN-DOC 29640

    SILVA, DANIEL J. da; DURAN, ADRIANA; CABRAL, ALINE D.; FONSECA, FERNANDO L.A.; WANG, SHU H.; PARRA, DUCLERC F. ; BUENO, RODRIGO F.; PEREYRA, INES; ROSA, DERVAL S.. Bioinspired antimicrobial PLA with nanocones on the surface for rapid deactivation of Omicron SARS-CoV‑2. ACS Biomaterials Science and Engineering, v. 9, n. 4, p. 1891-1899, 2023. DOI: 10.1021/acsbiomaterials.2c01529

    Abstract: Bioinspired bactericidal surfaces are artificial surfaces that mimic the nanotopography of insect wings and are capable of inhibiting microbial growth by a physicomechanical mechanism. The scientific community has considered them an alternative method to design polymers with surfaces that inhibit bacterial biofilm formation, suitable for self-disinfectant medical devices. In this contribution, poly(lactic acid) (PLA) with nanocone patterns was successfully produced by a novel two-step procedure involving copper plasma deposition followed by argon plasma etching. According to reverse transcription-quantitative polymerase chain reaction tests, the bioinspired PLA nanostructures display antiviral performance to inactivate infectious Omicron severe acute respiratory syndrome coronavirus 2 particles, reducing the amount of the viral genome to less than 4% in just 15 min due to a possible combined effect of mechanical and oxidative stress. The bioinspired antiviral PLA can be suitable for designing personal protection equipment to prevent the transmission of contagious viral diseases, such as Coronavirus Disease 2019.

    Palavras-Chave: coronaviruses; topography; surfaces; copper; lactic acid; polymers; antimicrobial agents

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  • IPEN-DOC 23165

    FEITOSA, SABRINA A.; LIMA, NELSON B. ; YOSHITO, WALTER K. ; CAMPOS, FERNANDA; BOTTINO, MARCO A.; VALANDRO, LUIZ F.; BOTTINO, MARCO C.. Bonding strategies to full-contour zirconia: Zirconia pretreatment with piranha solution, glaze and airborne-particle abrasion. International Journal of Adhesion and Adhesives, v. 77, p. 151-156, 2017. DOI: 10.1016/j.ijadhadh.2017.05.007

    Abstract: This study aimed to evaluate the effect of various zirconia surface pretreatments on the adhesion between full contour 3Y-TZP zirconia and glaze, and the shear bond strength (SBS) between glazed/3Y-TZP and resin cement. Specimens were allocated into groups: GL-glaze; AL+GL-sandblasting with Al2O3+GL; CJ+GL-tribochemical silica coating (Cojet (R)/CJ) + GL; PS+GL-piranha solution+GL; and CJ. Adhesion between 3Y-TZP and GL was evaluated using the scratch test. Surface topography and glaze thickness were evaluated by using a scanning electron microscope (SEM). For SBS, glazed/3Y-TZP surface was etched with hydrofluoric acid and a silane was applied. For CJ only the silane was applied. Samples were tested after 24 h (24 h wet) or after 15,000 thermal cycles and 90 days storage (thermocycled). After SBS, the type of failure was classified as: adhesive, mixed or cohesive. The data were analyzed using two-way ANOVA and Tukey's test. SEM analysis after scratch test revealed circular cracks in the GL group and conformal cracks in the others groups. SEM micrographs suggested that zirconia specimens submitted to airborne-particle abrasion presents rougher and porous surface when compared to surfaces treated with GL and PS. The glaze layer was approximately 1.86 mu m thick in all groups. After 24 h, SBS test showed highest values for AL + GL and CJ + GL and were significantly higher when compared to the GL group. Differences were not significant between PS + GL and the other groups. After aging (thermo-cycling + storage), groups GL and CJ presented no statistically significant difference compared to 24 h and aged AL+GL, CJ+GL and PS + GL groups. The predominant type of failure was mixed. 3Y-TZP surface treatment with glaze application could be considered as an alternative treatment, since it yielded a similar resin bond strength without the need for airborne-particle abrasion.

    Palavras-Chave: zirconium; ceramics; glazes; etching; aqueous solutions; sulfuric acid; hydrogen peroxide; oxidizers; shear; testing; surface treatments

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  • IPEN-DOC 27384

    COUTO, VERONICA M.; OLIVEIRA-NASCIMENTO, LAURA de; CABEÇA, LUIZ F.; GERALDES, DANILO C.; COSTA, JULIANA S.R.; RISKE, KARIN A.; FRANZ-MONTAN, MICHELLE; YOKAYCHIYA, FABIANO ; FRANCO, MARGARETH K.K.D. ; PAULA, ENEIDA de. Capsaicin-cyclodextrin complex enhances mepivacaine targeting and improves local anesthesia in inflamed tissues. International Journal of Molecular Sciences, v. 21, n. 16, p. 1-18, 2020. DOI: 10.3390/ijms21165741

    Abstract: Acidic environments, such as in inflamed tissues, favor the charged form of local anesthetics (LA). Hence, these drugs show less cell permeation and diminished potency. Since the analgesic capsaicin (CAP) triggers opening of the TRPV1 receptor pore, its combination with LAs could result in better uptake and improved anesthesia. We tested the above hypothesis and report here for the first time the analgesia effect of a two-drug combination (LA and CAP) on an inflamed tissue. First, CAP solubility increased up to 20 times with hydroxypropyl-beta-cyclodextrin (HP-β-CD), as shown by the phase solubility study. The resulting complex (HP-β-CD-CAP) showed 1:1 stoichiometry and high association constant, according to phase-solubility diagrams and isothermal titration calorimetry data. The inclusion complex formation was also confirmed and characterized by differential scanning calorimetry (DSC), X-ray diffraction, and 1H-NMR. The freeze-dried complex showed physicochemical stability for at least 12 months. To test in vivo performance, we used a pain model based on mouse paw edema. Results showed that 2% mepivacaine injection failed to anesthetize mice inflamed paw, but its combination with complexed CAP resulted in pain control up to 45 min. These promising results encourages deeper research of CAP as an adjuvant for anesthesia in inflamed tissues and cyclodextrin as a solubilizing agent for targeting molecules in drug delivery.

    Palavras-Chave: anesthesia; inflammation; anesthetics; dextrin; scanning electron microscopy; differential thermal analysis; calorimetry

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  • IPEN-DOC 27367

    LITVAC, D. ; CALDAS, L.V.E. . Caracterização dosimétrica do LiF-NRPB para calibração de aplicadores clínicos de betaterapia. Brazilian Journal of Radiation Sciences, v. 8, n. 1, p. 1-15, 2020. DOI: 10.15392/bjrs.v8i1A.1087

    Abstract: A National Radiological Protection Board era uma instituição que trabalhava com radioproteção pessoal e utilizava materiais dosimétricos de LiF. Um destes materiais, empregado antigamente na rotina de trabalho da instituição, consiste de uma placa de liga de alumínio, onde dois discos de politetrafluoroetileno carregados com fluoreto de lítio são retidos por anéis de alumínio. São oficializados, no Sistema Único de Saúde, procedimentos radioterápicos em betaterapia dérmica, betaterapia oftalmológica e betaterapia para profilaxia de pterígio. Na norma NN 3.01, “Diretrizes Básicas de Proteção Radiológica”, exige-se a calibração regular destes aplicadores. O objetivo deste trabalho foi caracterizar dosimetricamente as amostras de LiF-NRPB, verificar se são adequadas para utilização em um sistema para calibrações de aplicadores clínicos de betaterapia e identificar se há a possibilidade de novas aplicações dosimétricas.

    Palavras-Chave: angular correlation; beta particles; calibration; dose rates; dose-response relationships; dosimetry; lithium fluorides; microwave ovens; strontium 90; thermoluminescence; yttrium 90

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  • IPEN-DOC 29869

    PAGLIUSO, DEBORA; PEREIRA, JOAO P. de J.; ULRICH, JOAO C. ; COTRIM, MARYCEL E.B. ; BUCKERIDGE, MARCOS S.; GRANDIS, ADRIANA. Carbon allocation of Spirodela polyrhiza under boron toxicity. Frontiers in Plant Science, v. 14, p. 1-11, 2023. DOI: 10.3389/fpls.2023.1208888

    Abstract: Pectic polysaccharides containing apiose, xylose, and uronic acids are excellent candidates for boron fixation. Duckweeds are the fastest-growing angiosperms that can absorb diverse metals and contaminants from water and have high pectin content in their cell walls. Therefore, these plants can be considered excellent boron (B) accumulators. This work aimed to investigate the relationship between B assimilation capacity with apiose content in the cell wall of Spirodela polyrhiza subjected to different boric acid concentrations. Plants were grown for 7 and 10 days in ½ Schenck-Hildebrandt media supplemented with 0 to 56 mg B.L-1, the non-structural and structural carbohydrates, and related genes were evaluated. The results showed that B altered the morphology and carbohydrate composition of this species during plant development. The optimum B concentration (1.8 mg B.L-1) led to the highest relative growth and biomass accumulation, reduced starch, and high pectin and apiose contents, together with increased expression of UDP-apiose/UDP-xylose synthase (AXS) and 1,4-α-galacturonosyltransferase (GAUT). The toxic state (28 and 56 mg B.L-1) increased the hexose contents in the cell wall with a concomitant reduction of pectins, apiose, and growth. The pectin content of S. polyrhiza was strongly associated with its growth capacity and regulation of B content within the cells, which have AXS as an important regulator. These findings suggest that duckweeds are suitable for B remediation, and their biomass can be used for bioenergy production.

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  • IPEN-DOC 26864

    PARDO DIAZ, C.A.; SHIMOKAWA, C.A.K.; SAMPAIO, C.S.; FREITAS, A.Z. ; TURBINO, M.L.. Characterization and comparative analysis of voids in class II composite resin restorations by optical coherence tomography. Operative Dentistry, v. 45, n. 1, p. 71-79, 2020. DOI: 10.2341/18-290-L

    Abstract: Purpose: This study aimed to characterize and analyze the number of voids and the percentage of void volume within and between the layers of class II composite restorations made using the bulk fill technique or the incremental technique by optical coherence tomography (OCT). Methods and Materials: Class II cavities (43432 mm) were prepared in 48 human third molars (n=24 restorations per group, two class II cavities per tooth). Teeth were divided into four groups and restored as follows: group 1 (FOB), bulk filled in a single increment using Filtek One Bulk Fill (3M Oral Care); group 2 (FXT), incrementally filled using four oblique layers of Filtek Z350 XT (3M Oral Care); group 3 (FBF+FXT), bulk filled in a single increment using Filtek Bulk Fill Flowable Restorative (3M Oral Care) covered with two oblique layers of Filtek Z350 XT (3M Oral Care), and group 4 (FF+FXT), incrementally filled using Filtek Z350 XT Flow (3M Oral Care) covered with two oblique layers of Filtek Z350 XT (3M Oral Care). After the restorative procedure, specimens were immersed into distilled water and stored in a hot-air oven at 378C. Forty-eight hours later, thermal cycling was conducted (5000 cycles, 58C to 558C). Afterward, OCT was used to detect the existence of voids and to calculate the number of voids and percentage of voids volume within each restoration. Data were submitted to chi-square and Kruskal- Wallis tests (a=0.05). Comparisons were made using the Dunn method. Results: Voids were detected in all groups, ranging from 0.000002 (FBF+FXT and FF+FXT) to 0.32 mm3 (FBF+FXT). FF + FXT presented voids in all of the restorations and had a significantly higher number of voids per restoration when compared to the other groups (p,0.05), but restorations with the presence of voids were significantly higher only when compared to FXT (p,0.05). FBF + FXT presented a significantly higher percentage of voids volume than that of FXT (p,0.05). When comparing restorations made using high-viscosity resin-based composites (FOB and FXT), no significant differences regarding number of voids or percentage of voids volume were detected (p 0.05). Conclusions: The use of flowable resin-based composites can result in an increased number of voids and percentage of voids volume in restorations, and this appears to be more related to voids present inside the syringe of the material than to the use of incremental or bulk fill restorative techniques.

    Palavras-Chave: dentistry; resins; biological recovery; tomography; optical equipment; images; composite materials; voids; layers

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  • IPEN-DOC 27802

    VILLANI, D. ; SAVI, M. ; ANDRADE, M.A.B.; CAMPOS, L.L. ; POTIENS, M.P.A. . Characterization of ABS + W and ABS + Bi 3D printing filaments attenuation for different photon beams. Journal of Physics: Conference Series, v. 1826, p. 1-8, 2021. DOI: 10.1088/1742-6596/1826/1/012037

    Abstract: 3D printing techniques and materials have become widely available in the last couple of decades and remains a hot topic of study as new materials can lead to new applications. This study aims to evaluate the attenuation behaviour of GMASS over photon beams ranging from 29.7 up to 661.7keV, comparing with pure ABS and using theoretical data of pure lead as reference. It was used the transmission method to obtain experimental attenuation coefficients to all materials and theoretical data. HVL and TVL calculations were also performed. Results show that ABS+W has higher attenuation than ABS+Bi and pure ABS. Using the lead theoretical reference data it can be concluded that although ABS+Bi and ABS+W attenuates less than pure lead, the 3D printing filaments can be used to create shielding tolls depending on radiation energy and application.

    Palavras-Chave: attenuation; cesium 137; dosimetry; energy dependence; filaments; photon beams; polymers; radiations; shielding

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  • IPEN-DOC 27197

    POLO, IVON O. ; SANTOS, WILLIAM S. ; CALDAS, LINDA V.E. . Characterization of an extrapolation chamber in beta radiation beams and Monte Carlo modelling. Radiation Physics and Chemistry, v. 171, p. 1-9, 2020. DOI: 10.1016/j.radphyschem.2020.108746

    Abstract: At the Calibration Laboratory (LCI) of the IPEN/CNEN, studies are in development on the establishment of a standard composed by the beta radiation sources for the dosimetry and calibration for personal monitoring in Brazil. For this purpose is used the Böhm extrapolation chamber (PTW model 23392). This chamber was already characterized at LCI in 90Sr/90Y beams using two different entrance windows: one of aluminized Mylar and another of PET (polyethylene terephthalate) known as Hostaphan. In this work, this extrapolation chamber was characterized in 85Kr and 147Pm beams. All tests were carried out with the reference 90Sr /90Y source, for comparison purposes. The Monte Carlo code MCNP5 code was used to obtain an extrapolation chamber and the BSS2 system sources computational model, based on the determination of the absorbed dose rate. Saturation curves, ion collection efficiency, ion recombination, polarity effect, stability of response, null depth, linearity of response, variation of response as a function of source-detector distance, extrapolation curves, correction factors and absorbed dose rates were obtained. The difference between the experimental absorbed dose rates and those obtained using the Monte Carlo model, compared to those from the calibration certificates, was less than 1.9% for the 108 histories for each BSS2 system source. All results of the performed tests are within the limits of the international recommendations. The results for the 90Sr/90Y source were in good agreement with previous works performed at LCI. These results are suitable for the establishment of a standard instrument for the dosimetry and calibration of beta radiation sources and detectors in the LCI/IPEN. This standard will allow the calibration of detectors in beta radiation beams in dosimetry services in Brazil.

    Palavras-Chave: extrapolation chambers; radiation doses; beta sources; monte carlo method; calibration; calibration standards; laboratories

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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.

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.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

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.