Navegação Periódicos - Artigos por ano de publicação "2019"

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  • IPEN-DOC 25851

    BENEDETTO, RAQUEL ; MASSICANO, ADRIANA V.F.; CRENSHAW, BRYANT K.; OLIVEIRA, RENATO; REIS, RUI M.; ARAUJO, ELAINE B. ; LAPI, SUZANNE E.. Zr-89-DFO-cetuximab as a molecular imaging agent to identify cetuximab resistance in head and neck squamous cell carcinoma. Cancer Biotherapy and Radiopharmaceuticals, v. 34, n. 5, p. 288-296, 2019. DOI: 10.1089/cbr.2018.2616

    Abstract: Background: Despite the improvement in clinical outcomes for head and neck squamous cell carcinoma (HNSCC) as the result of cetuximab, patients may present with or develop resistance that increases tumor recurrence rates and limits clinical efficacy. Therefore, identifying those patients who are or become resistant is essential to tailor the best therapeutic approach. Materials and Methods: Cetuximab was conjugated to p-NCS-Bz-DFO and labeled with 89Zr. The resistance model was developed by treating FaDu cells with cetuximab. Western blotting (WB) and specific binding assays were performed to evaluate epidermal growth factor receptor (EGFR) expression and 89Zr-DFO-cetuximab uptake in FaDu cetuximab-resistant (FCR) and FaDu cetuximab-sensitive (FCS) cells. Positron emission tomography imaging and biodistribution were conducted in NU/NU nude mice implanted with FCR or FCS cells. Results: Cetuximab was successfully radiolabeled with 89Zr (‡95%). Binding assays performed in FCR and FCS cells showed significantly lower 89Zr-DFO-cetuximab uptake in FCR ( p < 0.0001). WB suggests that the resistance mechanism is associated with EGFR downregulation ( p = 0.038). This result is in agreement with the low uptake of 89Zr-DFO-cetuximab in FCR cells. Tumor uptake of 89Zr-DFO-cetuximab in FCR was significantly lower than FCS tumors ( p = 0.0340). Conclusions: In this work, the authors showed that 89Zr-DFO-cetuximab is suitable for identification of EGFR downregulation in vitro and in vivo. This radiopharmaceutical may be useful for monitoring resistance in HNSCC patients during cetuximab therapy.

    Palavras-Chave: zirconium 89; positron computed tomography; carcinomas; radiopharmaceuticals; therapy; chemotherapy; antibodies; reagents

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  • IPEN-DOC 26690

    BRAGA, ELISABETE S.; AZEVEDO, JULIANA S.; KUNIYOSHI, LEONARDO; FAVARO, DEBORAH I.T. . Zn, Co, Cr, As, and genotoxic effects in the ichthyofauna species from polluted and non-polluted/protected estuaries of the São Paulo coast, Brazil. Anais da Academia Brasileira de Ciências, v. 91, n. 4, p. 1-18, 2019. DOI: 10.1590/0001-3765201920190066

    Abstract: The human impact on estuarine regions results in an increasing concentration of trace elements in the environment, exposing aquatic organisms. In this study, Zn, Co, Cr, and As were determined in the muscle tissue of some fish species from Santos-São Vicente (SSV), a recognized polluted region, and in the Cananeia estuary (CAN). Genotoxicity was also determined for the evaluation of the chronic effect on ichthyofauna, to enlarge the bank of environmental data regarding the effects of pollution, and to suggest other fish bioindicator species that may contribute to monitoring programs. The obtained data showed a similar profile of an accumulation of Co and Zn in Micropogonias furnieri and Chaetodipterus faber, where: Santos Bay > CAN > inner area of SSV. A low frequency of micronucleus was observed. However, in general, fish from the inner area of the SSV estuary presented more nuclear abnormalities than fish from Santos Bay and CAN. In the inner area of SSV, Centropomus paralelus and Diapterus rhomneus showed more changes than other fish species. It was possible to consider that the habits of each species, contributed to a different profile of trace element accumulation, followed by the chemical components in the organism offering different vulnerability.

    Palavras-Chave: trace amounts; elements; erythrocytes; environmental impacts; resource conservation; environmental protection; aquatic ecosystems; estuaries; animal tissues; fishes; zinc; carbon monoxide; chromium; arsenic; brazil

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  • IPEN-DOC 25850

    FRIMAIO, AUDREW ; NASCIMENTO, BRUNA C.; BARRIO, RAMON M.M.; CAMPOS, LETICIA L. ; COSTA, PAULO R.. X-ray spectrometry applied for determination of linear attenuation coefficient of tissue-equivalent materials. Radiation Physics and Chemistry, v. 160, p. 89-95, 2019. DOI: 10.1016/j.radphyschem.2019.03.021

    Observação: Reprint anexado. Radiation Physics and Chemistry, v. 167, 2020. DOI: 10.1016/j.radphyschem.2019.108553

    Abstract: Resin-based materials equivalent to water were developed and four different samples were obtained. The linear attenuation coefficients of all samples was evaluated using X-ray spectrometry with primary and transmitted beams using voltages at the ranging from 60 to 120 kV. The experimental measured values were compared with theoretical reference values to water and with that obtained using the Least Square Method algorithm methodology (method applied to diagnostic radiology and radiotherapy). Our results show that differences between the measured values and the target μ(E) was lower than 7% ± 0.3 in the energy range from 20 to 80 keV. These results enable to consider that the material developed and produced is a good option to be used as a waterequivalent material and the experimental method adequate to its quantitative evaluation.

    Palavras-Chave: phantoms; x-ray tubes; tissue-equivalent materials; attenuation; spectroscopy; samplers; resins

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  • IPEN-DOC 25849

    BARROSO, A.G. ; GARCIA, R.H.L. ; DEL MASTRO, N.L. . X-ray diffraction pattern and relative crystallinity of irradiated arrowroot starch. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-7, 2019. DOI: 10.15392/bjrs.v7i2A.645

    Abstract: After cereals, tubers and roots are the major source of starch for food and industrial uses. Arrowroot refers to any plant of the genus Marantha, but the term is most commonly used to describe the easily digested starch ob-tained from the rhizomes of Marantha arundinacae. The rhizomes of this herbaceous plant contain about 20% of starch. As few studies exist on arrowroot starch, the objective of this preliminary work was to study the X-ray diffraction (XRD) patterns of arrowroot starch when treated by γ-radiation with doses up to 15 kGy in a 60Co source. The XRD patterns of the arrowroot starch exhibited A-type crystalline arrangements with strong peaks at approximately 15º, 17º, 18º and 23º (2θ). A slight increase of diffractogram peaks intensity was noticed after the irradiation process. The cristallinity index was calculated using Bruker DIFFRAC.EVA version 4.2 software. Relative crystallinity seems to increase with irradiation at low doses that could be attributed to different radia-tion sensitivity among the amorphous and crystalline regions of the arrowroot starch molecule. Present results will contribute to elucidate the behavior under radiation treatment of this starchy component increasingly em-ployed by the food industry.

    Palavras-Chave: x-ray diffraction; gamma radiation; starch; radiation effects; radiation doses; cobalt 60; crystal structure; irradiation

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  • IPEN-DOC 26529

    CARDOSO, QUEZIA de A. ; CASINI, JULIO C.S.; BARBOSA, LUZINETE P. ; SERNA, MARILENE M. ; GALEGO, EGUIBERTO ; SOBRINHO, LUIZA F. ; SAKATA, SOLANGE K. ; FARIA JUNIOR, RUBENS N. de . X-ray diffraction evaluation of the average number of layers in thermal reduced graphene powder for supercapacitor nanomaterial. Materials Science Forum, v. 958, p. 117-122, 2019. DOI: 10.4028/www.scientific.net/MSF.958.117

    Abstract: Graphene oxide (GO) can be partially reduced to graphene-like sheets by removing the oxygen-containing groups and recovering the conjugated structure. In this work, the thermal reduction of GO powder has been carried out using back pumping vacuum pressures and investigated employing X-ray diffraction analysis. The experimental results of estimating the number of graphene layers on the reduced powder at various temperatures (200 – 1000 °C) have been reported. Electrical changes have been produced in a graphene oxide with the vacuum reduction process. This study has shown that the ideal processing temperature for reducing graphene oxide nanomaterial was about 400 oC. It has also been shown that at 600 oC the number of layers in the reduced nanomaterial increased. The internal series equivalent resistance (ESR) has been improved substantially with the vacuum thermal treatment even at temperatures above 400 oC. ESR was reduced from 95.0 to about 13.8 Ω cm2 with this processing. These results showed that the process can be applied to the reduction of graphene oxide to produce supercapacitor nanomaterials. The advantage of employing this method is that the processing is a straightforward and low cost thermal treatment that might be used for large amount of nanocomposite material.

    Palavras-Chave: graphene; oxides; x-ray diffraction; vacuum systems; capacitors; capacitive energy storage equipment; nanomaterials; electrical properties

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  • IPEN-DOC 25848

    ICHIKAWA, R.U. ; LINHARES, H.M.S.M.D.; SILVA, A.S.B. da ; TEIXEIRA, M.I. ; RANIERI, I.M. ; TURRILLAS, X.; MARTINEZ, L.G. . X-ray diffraction analysis of KY3F10 nanoparticles doped with Nd and preliminary studies for its use in high-dose radiation dosimetry. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-13, 2019. DOI: 10.15392/bjrs.v7i2A.586

    Abstract: In this work, the structure and microstructure of Nd:KY3F10 nanoparticles was probed using X-ray synchrotron diffraction analysis. Rietveld refinement was applied to obtain cell parameters, atomic positions and atomic dis-placement factors to be compared with the ones found in literature. X-ray line profile methods were applied to determine mean crystallite size and crystallite size distribution. Thermoluminescent (TL) emission curves were measured for different radiation doses, from 0.10 kGy up to 10.0 kGy. Dose-response curves were obtained by area integration beneath the peaks from TL. The reproducibility of the results in this work has shown that this material can be considered a good dosimetric material.

    Palavras-Chave: nanoparticles; x-ray diffraction; radiation doses; doped materials; thermoluminescence; neodymium; yttrium fluorides; critical size; dose-response relationships; dosimetry

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  • IPEN-DOC 26451

    MACHADO, JOÃO P.S.L.; JELINEK, ANDREA R.; BICCA, MARCOS M.; STEPHENSON, RANDELL; GENEZINI, FREDERICO A. . West Gondwana orogenies and Pangaea break-up: thermotectonic effects on the southernmost Mantiqueira Province, Brazil. Journal of the Geological Society, v. 176, n. 6, p. 1056-1075, 2019. DOI: 10.1144/jgs2019-018

    Abstract: Through the joint use of apatite fission tracks (AFT) and (U–Th)/He analysis in apatite (AHe) and zircon (ZHe), we evaluate the thermotectonic evolution of the Sul-Rio-Grandense Shield (SRGS), southernmost Mantiqueira Province, Brazil. Formed during the assembly of West Gondwana (Neoproterozoic), the shield comprises four tectonostratigraphic terranes separated by regional faults and shear zones. The central and eastern terranes present Mesozoic AFT ages, whereas the western terrane ages are mostly late Paleozoic. AHe ages show considerable dispersion, although most are Mesozoic. ZHe ages from the east are early Permian, whereas the west presents Devonian ages. Inverse thermal modelling indicates a Devonian to Carboniferous cooling phase in the west, time correlated with orogenies occurring at the SW margin of Gondwana, which affected the regional geodynamics and are possibly linked to limited uplift of the shield. From the Permian to Jurassic a major cooling phase took place in the SRGS, probably related to lithosphere thinning and uplift preceding the South Atlantic rifting. Samples closer to the Atlantic coast suggest a subtle reheating after this event, provisionally linked to a geothermal disturbance related to ocean opening and associated magmatism. A final post-Paleocene cooling phase towards surface conditions affected the entire SRGS.

    Palavras-Chave: geologic history; tectonics; age estimation; earth crust; fission tracks; sedimentary basins; apatites; zircon; temperature dependence; brazil; thermal analysis

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  • IPEN-DOC 25847

    ANDRADE, ADRIANO B.; BISPO, GIORDANO F. da C.; MACEDO, ZELIA S.; BALDOCHI, SONIA L. ; YUKIHARA, EDUARDO G.; VALERIO, MARIO E.G.. VUV excited luminescence and thermoluminescence investigation on Er3+- or Pr3+-doped BaY2F8 single crystals. Optical Materials, v. 90, p. 238-243, 2019. DOI: 10.1016/j.optmat.2019.02.044

    Abstract: Photoluminescence (PL), thermoluminescence (TL) emission spectra and TL glow curves of barium yttrium fluoride (BaY2F8 – BaYF), undoped and doped with erbium (Er3+) or praseodymium (Pr3+) were measured to investigate the fundamental absorption (band gap – Eg), the nature of the trapping centers, as well as the electronic transitions of Ln3+ in BaYF host. The band gap energy Eg of BaY2F8 was determined by vacuum ultraviolet (VUV) excitation measurements to be around 11.2 eV. Additionally, the electronic transition from excited states of Ln3+ ions and the exciton state were also identified. TL emission spectra showed that the TL emission of doped samples is related to the Ln3+ ion, indicating that the related host trapping centers are not affected by the new trapping centers originated due the dopant ions. Trap depths were calculated by fitting the glow curves using a first order kinetics model. Host-related trapping centers were attributed to intrinsic defects such as Vk and F centers and the new TL peaks observed for Ere and Pr-doped samples was associated to the electrons trapping centers. These results lead us to propose a simple model to explain the origin of the TL emission in BaYF.

    Palavras-Chave: ultraviolet spectra; spectroscopy; barium fluorides; yttrium fluorides; thermoluminescence; photoluminescence; emission spectra; monocrystals

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  • IPEN-DOC 26689

    SAMPAIO, CAMILA S.; ARIAS, JESSICA F.; ATRIA, PABLO J.; CACERES, EDUARDO; DIAZ, CAROLINA P.; FREITAS, ANDERSON Z. ; HIRATA, RONALDO. Volumetric polymerization shrinkage and its comparison to internal adaptation in bulk fill and conventional composites: A μCT and OCT in vitroanalysis. Dental Materials, v. 35, n. 11, p. 1568-1575, 2019. DOI: 10.1016/j.dental.2019.07.025

    Abstract: Objective. To quantify the volumetric polymerization shrinkage (VPS) of different conventional and bulk fill resin composites, through micro-computed tomography (μCT), and qualitative comparison of gap formation through optical coherence tomography (OCT). Methods. Box-shaped class I cavities were prepared in 30 third-molars and divided into 5 groups (n = 6): G1- Filtek Z100 (Z100); G2- Tetric Evoceram Bulk Fill (TEC); G3- Tetric EvoFlow Bulk fill (TEF); G4- Filtek Bulk fill (FBU); and G5- Filtek Bulk fill Flowable (FBF). All groups were treated with Adper Single Bond Plus adhesive and light cured (Bluephase 20i). Each tooth was scanned three times using a μCT apparatus: after cavity preparation (empty scan); after cavity filling (uncured scan) and after light curing of the restorations (cured scan). The μCT images were imported into a three-dimensional rendering software, and volumetric polymerization shrinkage percentage was calculated (%) for each sample. In the same images, interfacial gaps in the pulpal floor were qualitatively evaluated. After μCT evaluation, the pulpal floor from each tooth was polished until a thin tooth structure was obtained and OCT images were obtained by scanning the pulpal portion. Gap formation was observed and qualitatively compared to the μCT images.

    Palavras-Chave: polymerization; shrinkage; volumetric analysis; computerized tomography; optical systems; optical modes; coherence length; resins; composite materials; biological recovery

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  • IPEN-DOC 26688

    BARCESSAT, ANA R. ; GURGEL-JUAREZ, NALIA C.; WETTER, NIKLAUS U. . Vital tooth bleaching using different techniques: a clinical evaluation. Future Dental Journal, v. xxx, n. xxx, p. xxx-xxx, 2019. DOI: 10.1016/j.fdj.2018.11.003

    Abstract: Objectives: This clinical trial aimed to evaluate dental color stabilization after different bleaching techniques. Methods: Four dental bleaching techniques were tested in 60 healthy volunteers aged from 25 to 35 years randomly assigned to four groups. Group 1 (G1): conventional in-office bleaching using 35% hydrogen peroxide. Group 2 (G2): in-office application of 3% hydrogen peroxide followed by in-office bleaching using 35% hydrogen peroxide. Group 3 (G3): in-office application of 3% hydrogen peroxide and activation with a light emitting diode (LED) lamp. Group 4 (G4): at-home bleaching using 10% carbamide peroxide. The color of canines and incisors was scored using a digital spectrophotometer to analyze lightness, chroma and hue. Results: All groups resulted in shade change. Lightness increased in all groups with no statistical difference among groups 60 days after finishing the treatment regardless of the technique used (p > 0.05). Differences were found in a short-term evaluation between some groups (p < 0.05). Chroma showed no statistical differences for central incisors after bleaching (p > 0.05). Analyzing canines, G4 showed higher chroma compared to G1 (p < 0.05) and G2 (p < 0.05). For hue, only G2 behaved differently for canines and incisors (p < 0.05). In other groups, hue scores decreased after bleaching. Conclusions: All techniques improved lightness. The addition of 3% hydrogen peroxide to conventional in-office whitening only increased appointment time, but no further benefits were noticed. Clinical relevance: This study is important to help clinicians deciding which is the most suitable dental bleaching for each patient in the current high aesthetic demanding world.

    Palavras-Chave: bleaching; dentistry; teeth; spectrophotometry; peroxides; aesthetics; color; hydrogen peroxide

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  • IPEN-DOC 25846

    SOUZA, C.H. ; SHORTO, J.M.B. ; SIQUEIRA, P.T.D. ; NUNES, M.G. ; SILVA JUNIOR, I.A. ; YORIYAZ, H. . Verification of angular dependence in MOSFET detector. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-11, 2019. DOI: 10.15392/bjrs.v7i2A.734

    Abstract: In vivo dosimetry is an essential tool for quality assurance programs, being a procedure commonly performed with thermoluminescent dosimeters (TLDs) or diodes. However, a type of dosimeter that has increasing popularity in recent years is the metal-oxide-semiconductor field effect transistor (MOSFET) detector. MOSFET dosimeters fulfill all the necessary characteristics to realize in vivo dosimetry since it has a small size, good precision and feasibility of meas-urement, as well as easy handling. Nevertheless, its true differential is to allow reading of dose in real time, enabling immediate intervention in the correction of physical parameters deviations and anticipation of small anatomical changes in the patient during treatment. In order for MOSFET dosimeter to be better accepted in clinical routine, information reporting performance should be available frequently. For this reason, this work proposes to verify reproducibility and angular dependence of a standard sensitivity MOSFET dosimeter (TN-502RD-H) for Cs-137 and Co-60 sources. Exper-imental data were satisfactory and MOSFET dosimeter presented a reproducibility of 3.3% and 2.7% (±1 SD) for Cs-137 and Co-60 sources, respectively. In addition, an angular dependence of up to 6.1% and 16.3% for both radioactive sources, respectively. It is conclusive that MOSFET dosimeter TN-502RD-H has satisfactory reproducibility and a considerable angular dependence, mainly for the Co-60 source. This means that although precise measurements, special attention must be taken for applications in certain anatomical regions in a patient.

    Palavras-Chave: mosfet; experimental data; dosemeters; dosimetry; in vivo; performance; cesium 137; cobalt 60; irradiation; neoplasms

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  • IPEN-DOC 25845

    CARVALHO, P.R. ; MUNITA, C.S. ; LAPOLLI, A.L. . Validity studies among hierarchical methods of cluster analysis using cophenetic correlation coefficient. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-14, 2019. DOI: 10.15392/bjrs.v7i2A.668

    Abstract: The literature presents many methods to produce data set clusters and the better method choice becomes hardest because the various combinations between them based on different dissimilarity measures can lead to different cluster patterns and false interpretations. Nevertheless, little effort has been expended in evaluating these methods empirically using an archeological data set. In this way, this work has the objective to develop a comparative study of the cluster analysis methods and to identify what is the most appropriate for an archeological data set. For this, 45 ceramic fragments samples data set was analyzed by instrumental neutron activation analysis (INAA). And, five hierarchical methods of cluster were used to this data set: Single linkage, Complete linkage, Average linkage, Centroid and Ward. The validation was done calculating cophenetic correlation coefficient values by a statistical program R and the comparison between them showed the average linkage method was more accurate for the 45 ceramic fragments samples data set. With this, the statistical program R showed be an tool option for other scientists to calculate their cophenetic correlation coefficient and to identify the more accurate methods for their archeological data set.

    Palavras-Chave: validation; neutron activation analysis; archaeology; quality control; comparative evaluations; ceramics; multivariate analysis; cluster analysis; elements

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  • IPEN-DOC 25844

    DEL NERO, R.A. ; NAKANDAKARI, M.V.N.; YORIYAZ, H. . Validating a virtual source model based in Monte Carlo method for profiles and percent depth doses calculation. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-8, 2019. DOI: 10.15392/bjrs.v7i2A.689

    Abstract: The Monte Carlo method for radiation transport has been adapted for medical physics application. More specifically, it has received more attention in clinical treatment planning with the development of more efficient computer simulation techniques. In linear accelerator modeling by the Monte Carlo method, the phase space data file (phsp) is an alternative representation for radiation source. However, to create a phase space file and obtain good precision in the results, it is necessary detailed information about the accelerator's head and commonly the supplier does not provide all the necessary data. An alternative to the phsp is the Virtual Source Model (VSM). This alternative approach presents many advantages for the clinical Monte Carlo application. This is the most efficient method for particle generation and can provide an accuracy similar when the phsp is used. This research propose a VSM simulation with the use of a Virtual Flattening Filter (VFF) for profiles and percent depth doses calculation. Two different sizes of open fields (40 x 40 cm² and 40 x 40 cm² rotated 45°) were used and two different source to surface distance (SSD) were applied: the standard 100 cm and custom SSD of 370 cm, which is applied in radiotherapy treatments of total body irradiation. The data generated by the simulation was analyzed and compared with experimental data to validate the VSM. This current model is easy to build and test.

    Palavras-Chave: calculation methods; monte carlo method; validation; radiation dose distributions; radiation transport; computerized simulation; v codes; whole-body irradiation; phase space

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  • IPEN-DOC 24743

    KIDO, HUELITON W.; GABBAI-ARMELIN, PAULO R.; AVANZI, INGRID R.; SILVA, ANTONIO C. da ; FERNANDES, KELLY R.; FORTULAN, CARLOS A.; RENNO, ANA C.M.. Vacuumed collagen-impregnated bioglass scaffolds: characterization and influence on proliferation and differentiation of bone marrow stromal cells. Journal of Biomedical Materials Research Part B: applied biomaterials, v. 107, n. 2, p. 211-222, 2019. DOI: 10.1002/jbm.b.34112

    Abstract: This study evaluated physical–chemical characteristics of a vacuumed collagen-impregnated bioglass (BG) scaffolds and bone marrow stromal cells (BMSCs) behavior on those composites. scanning electron microscope and energy dispersive xray spectroscope demonstrated collagen (Col) was successfully introduced into BG. Vacuum impregnation system has showed efficiency for Col impregnation in BG scaffolds (approximately 20 wt %). Furthermore, mass weight decreasing and more stabilized pH were observed over time for BG/Col upon incubation in phosphate buffered saline compared to plain BG under same conditions. Calcium evaluation (Ca assay) demonstrated higher calcium uptake for BG/Col samples compared to BG. In addition, BG samples presented hydroxyapatite crystals formation on its surface after 14 days in simulated body fluid solution, and signs of initial degradation were observed for BG and BG/Col after 21 days. Fourier transform infrared spectroscopy spectra for both groups indicated peaks for hydroxyapatite formation. Finally, a significant increase of BMSCs viability for both composites was observed compared to control group, but no increase of osteogenic differentiation-related gene expressions were found. In summary, BG/Col scaffolds have improved degradation, pH equilibrium and Ca mineralization over time, accompanied by hydroxyapatite formation. Moreover, both BG and BG/Col scaffolds were biocompatible and noncytotoxic, promoting a higher cell viability compared to control. Future investigations should focus on additional molecular and in vivo studies in order to evaluate biomaterial performance for bone tissue engineering applications.

    Palavras-Chave: vacuum systems; medium vacuum; impregnation; collagen; bone marrow cells; glass

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  • IPEN-DOC 25652

    DIAS-MORAES, MARCIA C. de ; LIMA, CASSIO A. ; FREITAS, ANDERSON Z. ; ARANHA, ANA C.C.; ZEZELL, DENISE M. . Using optical attenuation coefficient to monitor the efficacy of fluoride and Nd:YAG laser to control dentine erosion. Applied Sciences, v. 9, n. 7, 2019. DOI: 10.3390/app9071485

    Abstract: The present study evaluated the protective effects that are induced by fluoride and Nd:YAG laser irradiation to control dentine erosion. One hundred and twenty bovine dentine slabs were eroded with citric acid twice a day for a total period of 15 days. At day 10, the samples were randomly assigned into eight groups: C (Control); F (Fluoride); L1 (Nd:YAG laser, 1 W, 100 mJ, 79.5 J cm􀀀2); L2 (Nd:YAG laser, 0.7 W, 70 mJ, 55.7 J cm􀀀2); L3 (Nd:YAG laser, 0.5 W, 50 mJ, 39.7 J cm􀀀2); F + L1; F + L2; and, F + L3. Optical Coherence Tomography images were collected from the surface of the samples in order to monitor the alterations that were induced by erosion and the effectiveness of each treatment using the Optical Attenuation Coefficient (OAC). OAC values that were calculated for samples from groups C, F, L1, L3, FL1, and FL3 indicated no protective effects against the progression of erosive lesions. Samples from L2 and FL2 groups presented OAC values, indicating that laser irradiation under this condition did not induce the formation of craters on dentine tissue and promoted sufficient chemical and morphological changes to avoid the progression of dentine erosion.

    Palavras-Chave: teeth; demineralization; dentistry; erosion control; cattle; tomography; laser radiation; fluorides

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  • IPEN-DOC 25843

    YAMAGATA, C. ; LEME, D.R. ; CASTANHO, S.R.H.M. . Use of waste water glass as silica supplier in synthesis of pure and Mg-doped lanthanum silicate powders for IT-SOFC application. Journal of the European Ceramic Society, v. 39, n. 12, p. 3416-3420, 2019. DOI: 10.1016/j.jeurceramsoc.2019.03.045

    Abstract: Water glass in alkali solution (Na2SiO3/NaOH) an abundant effluent, generated in the alkaline fusion of zircon sand, represents a potential silica source to be converted in useful silica technological application. Actually, the generation of energy by environmental-friendly method is one of the major challenges for researchers. Solid Oxide Fuel Cells (SOFC) is efficient and environmentally clean technique to energy production, since it converts chemical energy into electrical power, directly. Apatite-type lanthanum silicates are promising materials for application as an electrolyte in intermediate temperature SOFC (IT-SOFC) because of their higher ionic conductivity, in temperatures of range 600–700 °C, than conventional zirconia electrolytes. In this work, pure (La9,56(SiO4)6O2,34) and Mg-doped (La9,8Si5,7Mg0,3O26,4) lanthanum silicate were synthesized, from that rich effluent. Using the sol-gel followed by precipitation method, the single crystalline apatite phase of both silicates was obtained by thermal treatment at 900 °C of their precursors. Sintered ceramic samples reached density of higher than 90%.

    Palavras-Chave: waste water; electrolytes; lanthanum silicates; synthesis; sol-gel process; glass; solid oxide fuel cells; precipitation; apatites; silicates

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  • IPEN-DOC 25842

    CARVALHO, LUMA R. de ; BONFIM, LETICIA ; VIEIRA, DANIEL P. . Use of 2-color flow cytometry to assess radiation-induced genotoxic damage on CHO-KI cells. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-13, 2019. DOI: 10.15392/bjrs.v7i2A.570

    Abstract: The micronucleus assay is an important technique used to evaluate genotoxic damage of chemical or physical agents (as ionizing radiations) on cells, based on quantification of cells bearing micronuclei, which are fragments derived from damage (breakage) of the DNA. Currently, this technique was updated to an automated approach that relies on plasma membrane dissolution to analyze fluorescent dye-labelled nuclei and micronuclei by flow cytometry. Cell suspensions were irradiated in PBS by a 60Co source in doses between 0 and 16 Gy, and incubat-ed by 72h. Cell membranes were lysed in the presence of SYTOX Green and EMA dyes, so EMA-stained nuclei could be discriminated as from dead cells, and nuclei and micronuclei could be quantified. Amounts of micronu-clei (percent of events) in the samples, were found to be proportional to radiation doses, and could be fitted to a linear-quadratic model (R² = 0.993). Only higher doses (8 and 16 Gy) and positive control could induce relevant increases in micronucleus amounts. The incorporation EMA showed an increase in irradiated cells. Mid- to high doses (4, 8 and 16 Gy) induced reduction of cell proliferation. Experiments showed the suitability of the tech-nique to replace traditional microscopy analysis in evaluation of the effects of ionizing radiations on cells, with possibility to use in biological dosimetry.

    Palavras-Chave: cell flow systems; cho cells; cell proliferation; cobalt 60; cell membranes; dosimetry; radiation doses; radiation effects; cell nuclei; gamma radiation

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  • IPEN-DOC 25841

    VIEIRA, LUDMILA C. ; ARAUJO, LEANDRO G. de; FERREIRA, RAFAEL V. de P.; SILVA, EDSON A. da; CANEVESI, RAFAEL L.S.; MARUMO, JULIO T. . Uranium biosorption by Lemna sp. and Pistia stratiotes. Journal of Environmental Radioactivity, v. 203, p. 179-186, 2019. DOI: 10.1016/j.jenvrad.2019.03.019

    Abstract: Biosorption-based technologies have been proposed for the removal of radionuclides from radioactive liquid waste containing organic compounds. Nevertheless, pytoremediation potential of uranium (U) by nonliving aquatic macrophytes Lemna sp. and Pistia stratiotes has not been previously addressed. In this study, uranium biosorption capacity by Pistia stratiotes and Lemna sp. was evaluated by equilibrium and kinetics experiments. The biomasses were added to synthetic and real waste solutions. The assays were tested in polypropylene vials containing 10 mL of uranium nitrate solution and 0.20 g of biomass. Solutions ranging from 0.25 to 84.03 mmol l−1 were employed for the assessment of uranium concentration in each macrophyte. The equilibrium time was 1 h for both macrophytes. Lemna sp. achieved the highest sorption capacity with the use of the synthetic solution, which was 0.68 mmol g−1 for the macrophyte. Since Lemna sp. exhibit a much higher adsorption capacity, only this biomass was exposed to the actual waste solution, being able to adsorb 9.24×10−3 mmol g−1 U (total). The results show that these materials are potentially applicable to the treatment of liquid radioactive waste.

    Palavras-Chave: sorption; uranium; biomass; adsorption; organic compounds; aquatic ecosystems; plants; radioactive wastes

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  • IPEN-DOC 25840

    APPANNABABU, S.; LICHTENTHALER, R.; ALVAREZ, M.A.G.; RODRIGUEZ-GALLARDO, M.; LEPINE-SZILY, A.; PIRES, K.C.C.; SANTOS, O.C.B.; SILVA, U.U.; FARIA, P.N. de; GUIMARÃES, V.; ZEVALLOS, E.O.N.; SCARDUELLI, V.; ASSUNÇÃO, M.; SHORTO, J.M.B. ; BARIONI, A.; ALCANTARA-NUNEZ, J.; MORCELLE, V.. Two-neutron transfer in the He-6 + Sn-120 reaction. Physical Review C, v. 99, n. 1, p. 014601-1 - 014601-7, 2019. DOI: 10.1103/PhysRevC.99.014601

    Abstract: A large yield of α particles produced in the 120Sn(6He, α) reaction was measured at 20.3-, 22.2-, 22.4-, and 24.5-MeV bombarding energies. The α particles are distributed over a broad energy range in the vicinity and below the elastic scattering 6He peak. Energy integrated α-particle cross sections have been obtained at θlab = 36◦, 40◦, and 60◦. The α energy distributions have been analyzed at a fixed laboratory angle (≈60◦) in terms of the reaction Q value, considering the 2n-transfer reaction kinematics 120Sn(6He, α)122Sn. A kinematical analysis of the Q-value distribution shows that the recoil system 120Sn + 2n is formed in highly excited states in the continuum, at increasing excitation energies as the bombarding energy increases. It is shown that by using Brink’s formula, the excitation energy depends on the transferred angular momentum following a linear relation with the square of the angular momentum, indicating that some kind of dinuclear rotating system is formed after the reaction.

    Palavras-Chave: two-nucleon transfer reactions; neutron transfer; alpha particles; helium 6 reactions; tin 120 reactions; nuclear reactions; radioactive ion beams

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  • IPEN-DOC 26111

    UMBELINO, U.; PIRES, K.C.C.; LICHTENTHALER, R.; SCARDUELLI, V.; SCOTTON, G.A.; LEPINE-SZILY, A.; GUIMARÃES, V.; LUBIAN, J.; PAES, B.; FERREIRA, J.L.; ALVAREZ, M.A.G.; SHORTO, J.M.B. ; APPANNABABU, S.; ASSUNÇÃO, M.; CONDORI, R.P.; MORCELLE, V.. Two-neutron transfer in 7Be + 9Be collisions. Physical Review C, v. 99, n. 6, p. 064617-1 - 064617-13, 2019. DOI: 10.1103/PhysRevC.99.064617

    Abstract: Elastic scattering and transfer cross sections for the 7Be + 9Be system have been measured at Elab = 23.1 MeV using the 7Be radioactive secondary beam produced at Radioactive Ion Beams in Brazil facility at the University of São Paulo. The elastic scattering has been measured by detecting the 7Be scattered at forward angles in the laboratory system. The transfer reaction 9Be(7Be, 9Be)7Be was identified by detecting the 9Be scattered at the same laboratory angles. The elastic angular distribution has been analyzed by optical model calculations using a Woods-Saxon form factor whose parameters have been varied to best reproduce the experimental data at forward angles. Coupled reaction channels calculations (CRC) have been performed to describe the transfer, considering the coupling to the transfer channel and including contributions to the ground state and to the first excited state of 7Be(1/2−; 429 keV) in the final state. The spectroscopic amplitudes used in the CRC calculation have been derived from shell-model calculations. Similar CRC calculations were applied to existing 9Be(p, t )7Be data to check the consistency of our results results for the (7Be, 9Be) transfer reaction.

    Palavras-Chave: beryllium 7; beryllium 9; elastic scattering; coupled channel theory; ion beams; neutrons; neutron beams; neutron transfer

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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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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.