89 results on '"CDTN/CNEN"'
Search Results
2. Metastable phases determination of U-2.5Zr-7.5Nb and U-3.0Zr-9.0Nb alloys by Rietveld method
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Ferraz, W. [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, CNEN, Av. Presidente Antonio Carlos 6.627, 31270-901 - Belo Horizonte, MG (Brazil)]
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- 2012
3. Use of solvent extraction technique in Brazilian uranium mills - an overview
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Morais, Carlos [Centro de Desenvolvimento da Tecnologia Nuclear CDTN/CNEN, Rua Mario Werneck, s/n, Campus da UFMG, Pampulha, 30123-970, Belo Horizonte, MG (Brazil)]
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- 2008
4. Modifying internal organization and surface morphology of siRNA lipoplexes by sodium alginate addition for efficient siRNA delivery
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Céline Hoffmann, Valérie Trichet, Waldemar A. A. Macedo, Armando da Silva Cunha, Angelo Malachias de Souza, Ismael González, Luis A. Córdova, Gracielle Ferreira Andrade, Stéphanie Finet, Danielle Campiol Arruda, Virginie Escriou, Pascal Bigey, Universidade Federal de Minas Gerais [Belo Horizonte] (UFMG), Unité de Technologies Chimiques et Biologiques pour la Santé (UTCBS - UM 4 (UMR 8258 / U1022)), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidad de Chile, Physiopathologie de la résorption osseuse et thérapie des tumeurs osseuses primitives, Université de Nantes (UN)-IFR26-Institut National de la Santé et de la Recherche Médicale (INSERM), Equipe Labellisée LIGUE 2012 [Nantes], Centro de Desenvolvimento da Tecnologia NuclearCDTN/CNEN, CDTN/CNEN, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Universidade Federal de Minas Gerais (UFMG), Universidade Federal de Minas Gerais, Department of Oral and Maxillofacial Surgery [Santiago, Chile], Universidad de Chile = University of Chile [Santiago] (UCHILE)-San Borja Arriarán University Hospital - Faculty of Dentistry [Santiago, Chile], Sarcomes osseux et remodelage des tissus calcifiés - INSERM U1238 (Phy-Os), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Bretagne Loire (UBL)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Nantes Université - UFR de Médecine et des Techniques Médicales (Nantes Univ - UFR MEDECINE), Nantes Université - pôle Santé, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Santé, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Universidad de Chile = University of Chile [Santiago] (UCHILE), and ESCRIOU, Virginie
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[CHIM.POLY] Chemical Sciences/Polymers ,Small interfering RNA ,[SDV.BIO]Life Sciences [q-bio]/Biotechnology ,Morphology (linguistics) ,Alginates ,Static Electricity ,cationic lipid ,Nanoparticle ,02 engineering and technology ,delivery system ,010402 general chemistry ,01 natural sciences ,Cell Line ,Biomaterials ,RNA interference ,Colloid and Surface Chemistry ,Cations ,Animals ,structure ,Particle Size ,RNA, Small Interfering ,Sodium alginate ,Chemistry ,nanoparticle ,Gene Transfer Techniques ,anionic polymer ,[SDV.SP]Life Sciences [q-bio]/Pharmaceutical sciences ,021001 nanoscience & nanotechnology ,Lipids ,[SDV.BIO] Life Sciences [q-bio]/Biotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,[SDV.SP] Life Sciences [q-bio]/Pharmaceutical sciences ,Mice, Inbred C57BL ,[CHIM.POLY]Chemical Sciences/Polymers ,Liposomes ,Biophysics ,Female ,Cytokine secretion ,0210 nano-technology ,Internal organization ,Intracellular - Abstract
International audience; Vectorized small interfering RNAs (siRNAs) are widely used to induce specific mRNA degradation in the intracellular compartment of eukaryotic cells. Recently, we developed efficient cationic lipid-based siRNA vectors (siRNA lipoplexes or siLex) containing sodium alginate (Nalg-siLex) with superior efficiency and stability properties than siLex. In this study, we assessed the physicochemical and some biological properties of Nalg-siLex compared to siLex. While no significant differences in size, ζ potential and siRNA compaction were detected, the addition of sodium alginate modified the particle morphology, producing smoother and heterogeneous particles characterized by transmission electron microscopy. We also noted that Nalg-siLex have surface differences observed by X-ray photoelectron spectroscopy. These differences could arise from an internal reorganization of components induced by the addition of sodium alginate, that is indicated by Small-Angle X-ray Scattering results. Moreover, Nalg-siLex did not trigger significant hepatotoxicity nor inflammatory cytokine secretion compared to siLex. Taken together these results suggest that sodium alginate played a key role by structuring and reinforcing siRNA lipoplexes, leading to more stable and efficient delivery vector.
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- 2019
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5. The effect of different annealing temperatures on tin and cadmium telluride phases obtained by a modified chemical route
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Ardisson, José [Centro de Desenvolvimento da Tecnologia Nuclear, CDTN/CNEN, Belo Horizonte, Minas Gerais (Brazil)]
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- 2012
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6. Steady-state grain growth in UO{sub 2}
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Lameiras, F [CDTN/CNEN, Belo Horizonte (Brazil)]
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- 1998
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7. Observation of magnons in Mn 2 Au films by inelastic Brillouin and Raman light scattering
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L. E. Fernandez-Outon, D. Givord, Sergio M. Rezende, V. M. T. S. Barthem, D. S. Maior, W. A. A. Macedo, Joaquim Mendes, M. Arana, A. Azevedo, F. Estrada, Universidade Federal de Pernambuco [Recife] (UFPE), Universidade Federal do Rio de Janeiro (UFRJ), Universidade Federal de Vicosa (UFV), Centro de Desenvolvimento da Tecnologia NuclearCDTN/CNEN, CDTN/CNEN, Micro et NanoMagnétisme (MNM ), Institut Néel (NEEL), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
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Materials science ,Physics and Astronomy (miscellaneous) ,Spintronics ,Condensed matter physics ,Magnon ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Light scattering ,Brillouin zone ,Condensed Matter::Materials Science ,symbols.namesake ,Magnetic anisotropy ,[PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other] ,0103 physical sciences ,symbols ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Anisotropy ,Raman spectroscopy ,Néel temperature ,ComputingMilieux_MISCELLANEOUS - Abstract
The intermetallic antiferromagnetic compound Mn2Au has been attracting considerable interest for antiferromagnetic spintronics due to its high Neel temperature and strong spin–orbit coupling. We report on the experimental investigation of the zero-wave number magnon frequencies in Mn2Au films using Brillouin and Raman inelastic light scattering techniques. The derived effective anisotropy field values are in close agreement with theoretical calculations. With the values of the anisotropy and exchange fields, the full magnon dispersion curves in Mn2Au were calculated. Due to the weak in-plane anisotropy, the k ∼ 0 frequency of the lower magnon branch, 121 GHz, is among the lowest for 3D antiferromagnets, suggesting that Mn2Au is a good candidate for realizing the generation of spin currents by antiferromagnetic resonance driven spin-pumping, as proposed theoretically.
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- 2017
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8. Significant Dzyaloshinskii-Moriya interaction at graphene-ferromagnet interfaces due to the Rashba effect
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Hongxin Yang, Gong Chen, Alexandre A. C. Cotta, Alpha T. N’Diaye, Sergey A. Nikolaev, Edmar A. Soares, Waldemar A. A. Macedo, Kai Liu, Andreas K. Schmid, Albert Fert, Mairbek Chshiev, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Ningbo Institute of Technology (NIT), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), University of California [Davis] (UC Davis), University of California, Centro de Desenvolvimento da Tecnologia NuclearCDTN/CNEN, CDTN/CNEN, Departamento de Fisica, Universidade Federal de Minas Gerais, ANR-14-CE26-0012,ULTRASKY,Skyrmions dans les couches magnétiques ultraminces en vue d'une spintronique basse consommation(2014), ANR-13-BS10-0005,SOspin,Courants de spin et couple de transfert de spin produits par des effets spin-orbites(2013), European Project: 696656,H2020,H2020-Adhoc-2014-20,GrapheneCore1(2016), THALES [France]-Centre National de la Recherche Scientifique (CNRS), University of California (UC), and Universidade Federal de Minas Gerais [Belo Horizonte] (UFMG)
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Materials science ,FOS: Physical sciences ,02 engineering and technology ,01 natural sciences ,law.invention ,law ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,General Materials Science ,010306 general physics ,Spin-½ ,Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics ,Spintronics ,Condensed matter physics ,Graphene ,Mechanical Engineering ,Skyrmion ,Materials Science (cond-mat.mtrl-sci) ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Coupling (physics) ,Ferromagnetism ,Mechanics of Materials ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology ,Chirality (chemistry) ,Rashba effect - Abstract
The possibility of utilizing the rich spin-dependent properties of graphene has attracted great attention in pursuit of spintronics advances. The promise of high-speed and low-energy consumption devices motivates a search for layered structures that stabilize chiral spin textures such as topologically protected skyrmions. Here we demonstrate that chiral spin textures are induced at graphene/ferromagnetic metal interfaces. This is unexpected because graphene is a weak spin-orbit coupling material and is generally not expected to induce sufficient Dzyaloshinskii-Moriya interaction to affect magnetic chirality. We demonstrate that graphene induces a new type of Dzyaloshinskii-Moriya interaction due to a Rashba effect. First-principles calculations and experiments using spin-polarized electron microscopy show that this graphene-induced Dzyaloshinskii-Moriya interaction can have similar magnitude as at interfaces with heavy metals. This work paves a new path towards two-dimensional material based spin orbitronics., Comment: 21 pages, 4 figures
- Published
- 2016
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9. Radiochemical methodologies applied to determination of zirconium isotopes in low-level waste samples from nuclear power plants
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Frédérique Bessueille-Barbier, Thiago César de Oliveira, Geraldo F. Kastner, Arno Heeren de Oliveira, Roberto Pellacani Guedes Monteiro, Departamento de Engenharia Nuclear UFMG/DEN, Universidade Federal de Minas Gerais [Belo Horizonte] (UFMG), Centro de Desenvolvimento da Tecnologia NuclearCDTN/CNEN, CDTN/CNEN, Plasma spectroscopies, hyphenated methods & speciation, Institut des Sciences Analytiques (ISA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Health, Toxicology and Mutagenesis ,Analytical chemistry ,010402 general chemistry ,010403 inorganic & nuclear chemistry ,7. Clean energy ,01 natural sciences ,12. Responsible consumption ,Analytical Chemistry ,[CHIM.ANAL]Chemical Sciences/Analytical chemistry ,Radiology, Nuclear Medicine and imaging ,Inductively coupled plasma mass spectrometry ,Spectroscopy ,Detection limit ,Chemistry ,business.industry ,Low-level waste ,Liquid scintillation counting ,Radiochemistry ,Public Health, Environmental and Occupational Health ,Radioactive waste ,Nuclear power ,Pollution ,0104 chemical sciences ,Nuclear Energy and Engineering ,Isotopes of zirconium ,business ,ZirconiumSelective separation methodLSCICP-MS ,Waste disposal - Abstract
International audience; The 93Zr determination in low-level radioactive wastes generated at nuclear power plants is an important issue for waste disposal purpose. This paper describes an analytical methodology developed for 93Zr determination based on selective separation using extractive resins associated with inductively coupled plasma mass spectrometry (ICP-MS) and liquid scintillation counting (LSC) measurements. The 93Zr results obtained for waste samples were in a good agreement for both techniques and the detection limits of 0.045 μg L−1 and 0.05 Bq L−1 were obtained for ICP-MS and LSC techniques respectively.
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- 2014
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10. Solutions of Negatively Charged Graphene Sheets and Ribbons
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Maoshuai He, Clascídia A. Furtado, Alain Pénicaud, Hassan Saadaoui, Carlos Drummond, Olivier Roubeau, Cristina Vallés, Marc Monthioux, Luca Ortolani, Centre de recherches Paul Pascal (CRPP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), Desenvolvimento da Tecnologia Nuclear, Istituto per la Microelettronica e i Microsistemi [Bologna] (IMM), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Nanotubes, Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Consiglio Nazionale delle Ricerche (CNR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
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Ribbons ,Graphene sheets ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Catalysis ,law.invention ,Graphite intercalation compound ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,law ,Wafer ,Composite material ,Graphene oxide paper ,Chemistry ,Graphene ,General Chemistry ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Interferometry ,Sarfus ,Mica ,0210 nano-technology ,Graphene nanoribbons - Abstract
International audience; Negatively charged graphene layers from a graphite intercalation compound spontaneously dissolve in N-methylpyrrolidone, without the need for any sonication, yielding stable, air-sensitive, solutions of laterally extended atom-thick graphene sheets and ribbons with dimensions over tens of micrometers. These can be deposited on a variety of substrates. Height measurements showing single-atom thickness were performed by STM, AFM, multiple beam interferometry, and optical imaging on Sarfus wafers, demonstrating deposits of graphene flakes and ribbons. AFM height measurements on mica give the actual height of graphene (ca. 0.4 nm).
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- 2008
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11. Measurement of iron self-diffusion in hematite single crystal by SIMS and comparison of cation self-diffusion in corundum-structure oxides
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SABIONI, Antonio.C.S, Huntz, Anne-Marie, DANIEL, A.M.J.M., MACEDO, W.A.A., 35400-000 MG, Universidade Federal de Ouro Preto (UFOP), Essonne 91, Université Paris-Sud - Paris 11 (UP11), 35400-000 Ouro-Preto, 30161-970, and CDTN/CNEN
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Physical Sciences - Abstract
International audience; Iron bulk self-diffusion coefficients were measured in Fe2O3 single crystals using an original methodology based on the utilization of 57Fe stable isotope as iron tracer, and depth profiling by secondary ion mass spectrometry (SIMS). The iron self-diffusion coefficients were measured along and perpendicular to c-axis direction, between 900 and 1100o C, in oxygen atmosphere. Along c-axis they can be described by D//c (cm2/s)= 5.2x106 exp [-510 (kJ/mol)/RT], and are close to reliable data available in the literature, obtained by means of radioactive techniques. Perpendicular to c-axis, Dπc (cm2/s)= 83 exp [-430 (kJ/mol)/RT], and the coefficients are smaller than coefficients along c-axis. The results are compared with previously obtained results of cation bulk self-diffusion in Cr2O3 and in Al2O3 single crystals.
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- 2005
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12. ESTUDO DA PREPARAÇÃO E DA MORFOLOGIA DE SUPERFÍCIE DE ALUMINA NANOPOROSA AUTO-ORGANIZADA
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Maximiliano Delany Martins, Elisa Marchezini Rodrigues, Ronald Arreguy Silva, Fapemig, and CDTN/CNEN
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Anodização de Alumínio ,Materials science ,Pore diameter ,Hexagonal crystal system ,Nanoporous ,Materiais ,Nanotecnologia ,Alumina nanoporosa. Anodização. Alumínio. Nanotecnologia ,Nanotechnology ,Metallic aluminum ,Aluminum oxide ,Nuclear chemistry - Abstract
A alumina nanoporosa é um material que apresenta nanocanais auto-ordenados espontaneamente em formato hexagonal. Produzida a partir da anodização do alumínio metálico, vem sendo usada como molde para produção de materiais em escala nanométrica. Este trabalho teve como objetivo o estudo da preparação e a caracterização morfológica da alumina nanoporosa auto-organizada. A alumina nanoporosa foi preparada seguindo-se a metodologia proposta por Masuda e Fukuda (1995), um método de dois passos de anodização que consiste em anodizar a amostra de alumínio, remover a camada de óxido de alumínio (alumina) formada e, em seguida, repetir o processo de anodização, sob as mesmas condições da primeira. Este procedimento resulta em alumina com poros de dimensão na faixa de dezenas de nanômetros, com estreita distribuição de tamanhos e com alto grau de ordenação.AbstractNanoporous alumina is a typical material that exhibits self-ordered nanochannels spontaneously organized in hexagonal shape. Produced by anodizing of metallic aluminum, it has been used as a template for production of materials at the nanoscale. This work aimed to study the preparation of nanoporous alumina by anodic anodizing of metallic aluminum substrates. The nanoporous alumina was prepared following the methodology proposed by Masuda and Fukuda (1995), a two-step method consisting of anodizing the aluminum sample in the potentiostatic mode, removing the layer of aluminum oxide (alumina) formed and then repeat the anodization process under the same conditions as the first anodization. This method produces nanoporous alumina with narrow pore diameter distribution and well-ordered structure.
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- 2013
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13. Structural, vibrational, and luminescent properties of pure and Ce-doped magnesium lithium aluminoborate glass.
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Santos AWS, Silveira IS, Meira-Belo LC, Novais ALF, and Souza DN
- Abstract
The objective of this work was to study the properties of new vitreous samples of pure BAlMgLi and Ce-doped BAlMgLi produced by the melt-quenching method. The structural and vibrational characteristics of the samples were analyzed using x-ray diffraction (XRD), vibrational Raman spectroscopy, and vibrational Fourier transform infrared spectroscopy (FTIR). Optically stimulated luminescence (OSL) and thermoluminescence (TL) techniques were also used to identify whether the samples showed a response to ionizing radiation. XRD analyses confirmed the predominance of the amorphous phase of the samples. The Raman spectra revealed that the atomic bonds present in the material matrix are of the pyroborate and metaborate type, enabling stretching vibrations in isolated BO
4 and/or Al-O or Al-O-B units. The band at approximately 810 cm-1 is characteristic of the formation of the boroxol ring, indicating that the presence of other elements in the matrix does not affect its glassy characteristics. The FTIR analyses reinforce the results found by Raman spectroscopy, because bands characteristic of low hygroscopic glasses were observed, due to the conversion of BO3 units into BO4 in triborate, tetraborate, and pentaborate groups. This conversion is due to dopant entrainment, which contributes to the high optical transparency of the samples. Their OSL and TL signals were reproducible with intensities dependent on the dopant concentration and radiation dose, with the most intense emissions resulting from 0.5% Ce concentrations., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Divanizia do Nascimento Souza reports equipment, drugs, or supplies was provided by Federal University of Sergipe. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
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14. Nanoformulated CHO-rPb27 vaccine enhances immunity and controls infection, mitigating lung inflammation and dysfunction during experimental Paracoccidioidomycosis in mice.
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Morais EA, Martins EMDN, Oliveira JAC, Melo EM, Mattos MS, Kraemer LR, Gomes DA, de Goes AM, and Russo RC
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- Animals, Mice, Antigens, Fungal immunology, Pneumonia prevention & control, Pneumonia drug therapy, Pneumonia immunology, Fungal Proteins immunology, Fungal Proteins pharmacology, Disease Models, Animal, Cricetulus, Nanoparticles chemistry, Mice, Inbred BALB C, Lung microbiology, Lung pathology, Lung immunology, Lung drug effects, Paracoccidioidomycosis immunology, Paracoccidioidomycosis prevention & control, Fungal Vaccines immunology, Paracoccidioides immunology
- Abstract
Paracoccidioidomycosis (PCM) is a systemic mycosis caused by the dimorphic fungus within the genus Paracoccidioides, particularly Paracoccidioides brasiliensis. The traditional approach to treating this pulmonary infection involves prolonged therapy periods, ranging from weeks to years, often resulting in a notable frequency of disease relapse. Nanotechnology has emerged as a promising avenue for developing novel antifungal therapies and effective vaccines. This is attributed to its capability to facilitate targeted drug and antigen delivery, thereby mitigating toxicity and treatment expenses. This study investigates the synergistic properties of the CHO-rPb27 vaccine nanoformulation against experimental PCM. The therapeutic efficacy of CHO-rPb27 treatment is juxtaposed with the prophylactic protocol. Our findings demonstrate that both protocols effectively control P. brasiliensis pulmonary infection by eliciting a robust cellular and humoral immune response. This response attenuates chronic tissue damage and mitigates pulmonary mechanical dysfunction in mice., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)
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- 2024
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15. Comparison of the dosimetry of scandium-43 and scandium-44 patient organ doses in relation to commonly used gallium-68 for imaging neuroendocrine tumours.
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Gomes CV, Mendes BM, Paixão L, Gnesin S, Müller C, van der Meulen NP, Strobel K, Fonseca TCF, and Lima TVM
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Background: Several research groups have explored the potential of scandium radionuclides for theragnostic applications due to their longer half-lives and equal or similar coordination chemistry between their diagnostic and therapeutic counterparts, as well as lutetium-177 and terbium-161, respectively. Unlike the gallium-68/lutetium-177 pair, which may show different in-vivo uptake patterns, the use of scandium radioisotopes promises consistent behaviour between diagnostic and therapeutic radiopeptides. An advantage of scandium's longer half-life over gallium-68 is the ability to study radiopeptide uptake over extended periods and its suitability for centralized production and distribution. However, concerns arise from scandium-44's decay characteristics and scandium-43's high production costs. This study aimed to evaluate the dosimetric implications of using scandium radioisotopes with somatostatin analogues against gallium-68 for PET imaging of neuroendocrine tumours., Methods: Absorbed dose per injected activity (AD/IA) from the generated time-integrated activity curve (TIAC) were estimated using the radiopeptides [
43/44/44m Sc]Sc- and [68 Ga]Ga-DOTATATE. The kidneys, liver, spleen, and red bone marrow (RBM) were selected for dose estimation studies. The EGSnrc and MCNP6.1 Monte Carlo (MC) codes were used with female (AF) and male (AM) ICRP phantoms. The results were compared to Olinda/EXM software, and the effective dose concentrations assessed, varying composition between the scandium radioisotopes., Results: Our findings showed good agreement between the MC codes, with - 3 ± 8% mean difference. Kidneys, liver, and spleen showed differences between the MC codes (min and max) in a range of - 4% to 8%. This was observed for both phantoms for all radiopeptides used in the study. Compared to Olinda/EXM the largest observed difference was for the RBM, of 21% for the AF and 16% for the AM for scandium- and gallium-based radiopeptides. Despite the differences, our findings showed a higher absorbed dose on [43/44 Sc]Sc-DOTATATE compared to its68 Ga-based counterpart., Conclusion: This study found that [43/44 Sc]Sc-DOTATATE delivers a higher absorbed dose to organs at risk compared to [68 Ga]Ga-DOTATATE, assuming equal distribution. This is due to the longer half-life of scandium radioisotopes compared to gallium-68. However, calculated doses are within acceptable ranges, making scandium radioisotopes a feasible replacement for gallium-68 in PET imaging, potentially offering enhanced diagnostic potential with later timepoint imaging., (© 2024. The Author(s).)- Published
- 2024
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16. Use of tritium in characterizing the leachate migration from a landfill - Central de tratamento de resíduos sólidos (CTRS) BR040 (Belo Horizonte, Minas Gerais, Brazil).
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Oliveira RC, Filho CAC, Moreira RM, and Knupp EN
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- Tritium analysis, Brazil, Waste Disposal Facilities, Water, Environmental Monitoring methods, Water Pollutants, Chemical analysis, Refuse Disposal, Radiation Monitoring, Groundwater
- Abstract
Landfills often become a source of environmental impact due to the percolation of the leachate (liquid resulting from the decomposition of buried waste), which can eventually disperse and contaminate the soil and water bodies. This study aimed to evaluate quantitatively and spatially the leachate plume from the former Belo Horizonte landfill in the Coqueiros and Taiobas watersheds by using tritium (
3 H) concentration in nineteen (19) sampling points: 14 groundwater, 4 surface water and 1 leachate. Among the methodologies applied to determine the3 H content in the leachate, pre-filtration proved to be the most effective due to the ease treating of the sample, as well as the identical results obtained compared to the traditional method. The3 H contents resulted in concentrations up to thirty times higher in the leachate (=96,19 to 111,87 TU) and ten times in groundwater (PM23/3 = 45,06 TU), compared to the calculated threshold (TS) of rainfall tritium (TS_3 Hrain = 3,41 TU). Temporal series results indicate no trend and no influence of seasonality regarding the entry of pluvial tritium, leachate liquid level and wells water level. The3 H contour maps shows a transport of the mixture (water and leachate) towards the Coqueiros stream, with a higher concentration of leachate in wells closer to the landfill slope (PM13, PM14, PM15, and PM23) and in the southwest margin of the Coqueiros stream (PM17). In the furthest portion of the landfill,3 H levels are higher than the base threshold only at the deepest level of PM20 (=3,90 TU), possibly due to factors such as: i) denser character of the leachate compared to groundwater; ii) greater influence of recharge for regions further away from the landfill slope; and iii) the presence of the rock about 50 m from the surface. Based on the hydrogeological conceptual model, the transport of the leachate water mixture in the groundwater water compartment of the Coqueiros watershed basin seems to follow a piston or dispersion flow, with a small Peclet number (Pd = 0,05, as an example), as indicated by the high correlation coefficient values (R2 ≈ 0,85 to 0,99) from graphic interpolation. The mixture of water and leachate results in a transient time (tt ) ≈ 30 years and linear velocity (Vl ) ≈ 3-14 m/year in the interpolated sections. These indicate a coherent correlation with the mean hydraulic conductivity (K ≈ 29,34 m/year), as they result in effective porosity values between (Ne) ≈ 0.16 to 0.36, which corresponds to Ne range for unconsolidated sediments, similar to the wells lithotype profiles. Time series evaluation combined with lumped parameter approach suggest to be an interesting way to better understanding the HCM, and, therefore, to determine hydrodynamic parameters using tritium as a tracer., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2024
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17. Calcium ferrites for phosphate adsorption and recovery from wastewater.
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Araújo MHP, Ardisson JD, Krohling AC, Lago RM, Guimarães Júnior W, and Tristão JC
- Abstract
In this study, calcium ferrites with different Ca : Fe atomic ratios (1 : 1, 1 : 2, 1 : 3 and 2 : 1) were prepared from Ca and Fe nitrates treated at 300, 700 and 900 °C and evaluated for phosphate adsorption and recovery from wastewater. TG, XRD, Mössbauer spectroscopy, SEM, VSM magnetic measurements, and BET analyses showed the formation of two different calcium ferrite phases, i.e. , CaFe
2 O4 and Ca2 Fe2 O5 at 700 and 900 °C. The adsorption results indicated that the formation of calcium ferrite structure is critical for phosphate adsorption/recovery. Evaluation of the pH, initial phosphate concentration, contact time, coexisting ions and desorption conditions showed remarkable adsorption capacities of 62-75 mg g-1 for CaFe1:2-700 and 28-43 mg g-1 for CaFe1:2-900. The phosphate adsorption on the Ca ferrite surfaces is so strong that the recovery/desorption showed limited efficiencies, e.g. , 15-39%., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2024
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18. Heating Capacity and Biocompatibility of Hybrid Nanoparticles for Magnetic Hyperthermia Treatment.
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Gomes AA, Valverde TM, Machado VO, do Nascimento da Silva E, Fagundes DA, Oliveira FP, Freitas ETF, Ardisson JD, Ferreira JMDF, Oliveira JAC, Gomes ER, Rodrigues CF, Goes AM, Domingues RZ, and Andrade ÂL
- Subjects
- Humans, Hyperthermia, Electricity, Heating, Hyperthermia, Induced
- Abstract
Cancer is one of the deadliest diseases worldwide and has been responsible for millions of deaths. However, developing a satisfactory smart multifunctional material combining different strategies to kill cancer cells poses a challenge. This work aims at filling this gap by developing a composite material for cancer treatment through hyperthermia and drug release. With this purpose, magnetic nanoparticles were coated with a polymer matrix consisting of poly (L-co-D,L lactic acid-co-trimethylene carbonate) and a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer. High-resolution transmission electron microscopy and selected area electron diffraction confirmed magnetite to be the only iron oxide in the sample. Cytotoxicity and heat release assays on the hybrid nanoparticles were performed here for the first time. The heat induction results indicate that these new magnetic hybrid nanoparticles are capable of increasing the temperature by more than 5 °C, the minimal temperature rise required for being effectively used in hyperthermia treatments. The biocompatibility assays conducted under different concentrations, in the presence and in the absence of an external alternating current magnetic field, did not reveal any cytotoxicity. Therefore, the overall results indicate that the investigated hybrid nanoparticles have a great potential to be used as carrier systems for cancer treatment by hyperthermia.
- Published
- 2023
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19. Evaluation of amino acid profile by targeted metabolomics in the eukaryotic model under exposure of benzo[a]pyrene as the exclusive stressor.
- Author
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Batista JM, Neves MJ, Menezes HC, and Cardeal ZL
- Subjects
- Humans, Eukaryota, Benzo(a)pyrene toxicity, Gas Chromatography-Mass Spectrometry, Metabolomics, Glutamic Acid, Amines, Amino Acids, Nanotubes, Carbon
- Abstract
Amino acids (AAs) are a class of important metabolites in metabolomics methodology that investigates metabolite changes in a cell, tissue, or organism for early diagnosis of diseases. Benzo[a]pyrene (BaP) is considered a priority contaminant by different environmental control agencies because it is a proven carcinogenic compound for humans. Therefore, it is important to evaluate the BaP interference in the metabolism of amino acids. In this work, a new amino acid extraction procedure (derivatized with propyl chloroformate/propanol) using functionalized magnetic carbon nanotubes was developed and optimized. A hybrid nanotube was used followed by desorption without heating, and excellent extraction of analytes was obtained. After exposure of Saccharomyces cerevisiae, the BaP concentration of 25.0 μmol L
-1 caused changes in cell viability, indicating metabolic changes. A fast and efficient GC/MS method using a Phenomenex ZB-AAA column was optimized, enabling the determination of 16 AAs in yeasts exposed or not to BaP. A comparison of AA concentrations obtained in the two experimental groups showed that glycine (Gly), serine (Ser), phenylalanine (Phe), proline (Pro), asparagine (Asn), aspartic acid (Asp), glutamic acid (Glu), tyrosine (Tyr), and leucine (Leu) statistically differentiated, after subsequent application of ANOVA with Bonferroni post-hoc test, with a confidence level of 95%. This amino acid pathway analysis confirmed previous studies that revealed the potential of these AAs as toxicity biomarker candidates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)- Published
- 2023
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20. Results and analysis of an intercomparisons study for individual monitoring services of Latin American and Caribbean regions.
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Khoury H, Menchaca I, Andres P, de Barros V, Silva E, Alonso T, Molina D, Noguera G, Videla R, Rubio J, Bastidas B, Quintero C, Castillo R, Castillo A, Kawas N, Grant C, Garcia AL, Martinez E, Mora J, and Suarez RC
- Subjects
- Humans, Caribbean Region, Latin America, Radiation Dosage, Occupational Exposure analysis, Radiation Monitoring methods, Radiation Protection methods
- Abstract
The aim of this paper is to present the results obtained by the Latin-American and Caribbean personal dosimetry services that participated, with the support of IAEA, in the 2020-Eurados whole-body dosemeter intercomparison for photon radiation. All participant services in this study use thermoluminescent dosimetry (TLD) systems except one that uses optically stimulated luminescence (OSL) dosemeters. Data analysis shows that 93.4% of the results are within the acceptance range, according to International ISO Standard ISO 14146: 2018. The evaluation of the trumpet curves shows that only three laboratories presented a few dosemeters results outside the limits of acceptability. Participation in this Eurados intercomparison exercise gave the Latin American and Caribbean laboratories the opportunity to show compliance with their own quality management system, to compare results with other participants and to develop plans for improving their dosimetry systems. It also gave the assurance that occupational doses are being measured properly and following the international standards in the regions., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2023
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21. Analysis of the relationship between global breast density and maximum points of breast density in a sample of Brazilian women.
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Engler C and Nogueira MS
- Subjects
- Humans, Female, Brazil, Mammography methods, Software, Breast Density, Breast Neoplasms
- Abstract
Maximum points of breast density have been strongly associated with breast cancer masking than global breast density, which is a widely used measure today. The objective of this work was to verify the correlation between two measures of global breast density (VBD
GLOBAL and DABGLOBAL ) and a measure of maximum point breast density (VBDMP ). Mammographic images of 4.020 patients were analyzed using the Volpara software, which calculated or extracted the variables needed for the study from the DICOM header. Two-tailed partial correlation tests were performed between the variable VBDGLOBAL with VBDMP and DABGLOBAL with VBDMP in the following contexts: keeping PA and CBT constant, keeping only CBT constant, and keeping only PA constant. The Pearson test was also used to verify the bivariate correlation between VBDGLOBAL with VBDMP and DABGLOBAL with VBDMP . For the two-tailed partial correlation tests between VBDGLOBAL with VBDMP , keeping the CBT and PA variables constant resulted in r = 0.845 (p < 0.05). When kept constant only the CBT, r = 0.875 (p < 0.05), and keeping only the PA constant r = 0.866 (p < 0.05). Pearson's test showed r = 0.883 (p < 0.05). For the two-tailed partial correlation tests between the DABGLOBAL with VBDMP quantities, the results were r = 0.675 (p < 0.05), r = 0.725 (p < 0.05) and r = 0.701 (p < 0.05) for constant CBT and PA, constant CBT and constant PA, respectively, while the Pearson test resulted in r = 0.738 (p < 0.05). We conclude that a woman who has high global breast density is also highly likely to have maximum points of breast density., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2023
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22. Monte Carlo calculation of whole body counter efficiency factors for different computational phantoms.
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Ferreira CVG, Piedade JS, Prado MRD, Benavente J, Mendes BM, Paixão L, and Fonseca TCF
- Subjects
- Humans, Computer Simulation, Phantoms, Imaging, Monte Carlo Method, Whole-Body Counting methods, Radiometry methods
- Abstract
Individual monitoring can provide an estimate of the radioactivity present in the body of the exposed individuals. Periodic monitoring of occupationally exposed individuals is of great importance in case of accidental incorporation. Computational phantoms and Monte Carlo codes are often used to complement the calibration method of counting systems in internal dosimetry. Here, counting efficiency (CE) factors for a WBC system were calculated using MC simulations. The WBC system with a NaI(Tl) detector and the BOMAB phantom was modeled using three MC codes. After validation, the models were used to obtain CE values for a wide range of energies, and a CE curve was generated for the WBC system. To estimate the effects of anatomical differences on the measurement process, two anthropomorphic voxel phantoms were modeled using the VMC code. For the detector position with the highest CE value, the differences when comparing BOMAB results with the MaMP and Yale results were (-1 ± 6)% and (-1 ± 3)%, respectively. The results confirm that the use of the BOMAB phantom is a good approach for the calibration of the whole-body counter system. Measurements should be made at detector position with the highest CE values, and it is recommended to use the mean Monte Carlo CE values calculated in this work., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The following Brazilian institutions support this research project: Research Support Foundation of the State of Minas Gerais (FAPEMIG), Brazilian Council for Scientific and Technological Development (CNPq) and Coordination for the Capacitation of Graduated Personnel (CAPES). Computing resources were provided by the Laboratório de Ciências Radiológicas — LCR (http://www.lcr.uerj.br/) at Universidade Estadual do Rio de Janeiro., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2023
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23. Cancer risk in healthy patients who underwent chest tomography comparing three different technologies.
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Pedrosa KFS, Engler C, and Nogueira MS
- Subjects
- Male, Humans, Female, Adolescent, Young Adult, Adult, Middle Aged, Aged, Aged, 80 and over, Radiation Dosage, Risk, Software, Breast, Tomography, X-Ray Computed adverse effects, Tomography, X-Ray Computed methods, Neoplasms diagnostic imaging, Neoplasms epidemiology
- Abstract
This research aimed to estimate the risk of cancer associated with patients without previous disease undergoing chest tomography. Siemens CT scanners have 6, 64, and 128 detectors. The Biologic Effects of Ionizing Radiation Reports - BEIR VII methodology was used. The study presented a sample of 64 patients aged between 18 and 80 years, in the city of Belo Horizonte, Minas Gerais - Brazil. The IMPACT CT software and CalDose X CT Online were used to calculate the absorbed and equivalent dose from the Volumetric Computed Tomography Dose Index - CTDIvol (mGy) and Dose Length Product - DLP values provided by the equipment. CT-Expo Software was also used to estimate Specific Dose Estimates (SSDEs) values. The CTDvol results for the MG1, MG,2 and MG3 Diagnostic Centers in mGy were respectively 4.369 ± 1.352, 6.99 4 ± 1.53,3 and 9.984 ± 2.282 and the SSDE values were 3.800, 6.40,0 and 9,.500. The values for the equivalent dose, at the MG2 Diagnostic Center, by IMPACT CT, in (mSv) for the breasts, esophagus, heart, thyroid, lung and thymus were respectively 3.9, 5.7, 4.7, 1.0, 4.8 and 5.7. The CalDose Software, for the same equipment and the same organs, in mSv, estimated the values 7.4, 9.4, 11.1, 5.3, 10.8 and 11.3 for women and 7.1, 9.3, 11.0, 5.3, 10.2 and 10.9 for men. The estimated risk of cancer decreased according to the patient's age, but with a higher incidence for females. The use of each software must be carefully analyzed to avoid undue values due to the particularities of each one. The results also showed that the risk of developing cancer due to radiation decreases with patient age and is higher in females., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2023
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24. Characterization of irradiation channels in the carousel of TRIGA Mark I IPR-R1 research reactor, Brazil, aiming at the application of k 0 -standardization method of neutron activation analysis.
- Author
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Menezes MÂBC, Campolina DAM, and Jaćimović R
- Abstract
New values of neutron fluxes and spectral parameters f and α were determined experimentally in all irradiation devices of the TRIGA Mark I IPR-R1 nuclear research reactor at Nuclear Technology Development Centre (CDTN), Belo Horizonte, Brazil. Sets of monitors Au, Fe, Zn and Zr were irradiated bare and Cd-covered, according to "Cd-ratio for multi-monitor" method. Values were validated by analysing the certified reference material BCR-320R irradiated in chosen channels. The calculations were made based on irradiation channel values and the average values of the Carousel. The results of E
n - score point out that the k0 -method is producing reliable results. From now on, the values of mass fractions in several matrices, the production and studies with radioisotopes will be more accurate and the activities calculated more precisely., (© Akadémiai Kiadó, Budapest, Hungary 2023, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)- Published
- 2023
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25. Liquid phase exfoliation of talc: effect of the medium on flake size and shape.
- Author
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Sousa SM, Morais HLO, Santos JCC, Barboza APM, Neves BRA, Pinto ES, and Prado MC
- Abstract
Industrial applications of nanomaterials require large-scale production methods, such as liquid phase exfoliation (LPE). Regarding this, it is imperative to characterize the obtained materials to tailor parameters such as exfoliation medium, duration, and mechanical energy source to the desired applications. This work presents results of statistical analyses of talc flakes obtained by LPE in four different media. Talc is a phyllosilicate that can be exfoliated into nanoflakes with great mechanical properties. Sodium cholate at two different concentrations (below and at the critical micelar concentration), butanone, and Triton-X100 were employed as exfoliation medium for talc. Using recent published statistical analysis methods based on atomic force microscopy images of thousands of flakes, the shape and size distribution of nanotalc obtained using the four different media are compared. This comparison highlights the strengths and weaknesses of the media tested and hopefully will facilitate the choice of the medium for applications that have specific requirements., (Copyright © 2023, Sousa et al.)
- Published
- 2023
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26. Calculation of absorbed dose in paediatric phantoms using Monte Carlo techniques for 18 F-FDG and 99m Tc-DMSA and the new TIAC.
- Author
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Ferreira CVG, Mendes BM, Paixão L, Lima TVM, Santos-Oliveira R, and Fonseca TCF
- Subjects
- Adult, Infant, Humans, Child, Monte Carlo Method, Phantoms, Imaging, Succimer, Fluorodeoxyglucose F18, Radiopharmaceuticals
- Abstract
The radiopharmaceuticals most commonly used in nuclear medicine are
18 F-FDG and99m Tc-DMSA, both of which are administered to paediatric and adult patients using the same time activity coefficient. However, the IAEA recommends specific paediatric dosimetry. The aim of this work (TW) was to estimate the absorbed dose for18 F-FDG and99m Tc-DMSA using two paediatric voxel phantoms (Baby and Child) by Monte Carlo techniques. Biokinetic data for both radiopharmaceuticals were obtained from ICRP 128. In addition, the new time-integrated activity coefficient (TIAC) values from a recent publication were examined for the following organs: Brain, urinary bladder wall, liver, heart wall, and lung. The absorbed dose per injected activity (AD/IA) and effective dose per injected activity (E/IA) values were calculated for both phantoms and the results were compared with simulated data of paediatric phantoms from ICRP 128, MIRDcalc software and available literature. Regarding AD/IA in organs, differences of up to 61% and 115% were found for the Baby phantom and 120% and 167% for the Child phantom using18 F-FDG and99m Tc-DMSA, respectively. For FDG using the new TIAC, a maximum difference of 244% was observed. For E/IA, the maximum differences were 27% and 31% for the Baby and Child phantoms, respectively, for FDG and DSMA. In this study, new dosimetric data were calculated using Baby and Child phantoms and the newly recommended TIAC., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The following Brazilian institutions support this research project: Research Support Foundation of the State of Minas Gerais (FAPEMIG), Brazilian Council for Scientific and Technological Development (CNPq) and Coordination for the Capacitation of Graduated Personnel (CAPES). Prof. T. Fonseca is grateful for the financial support provided by CNPq (n°450493/2019-9425 and AVG. 450493/2019-9) and FAPEMIG (Project APQ-01388-21 Processo n°2070.01.0005404/2021-81). Computing resources were provided by the Laboratório de Computação Científica/CENAPAD-MG (http://www.lcc.ufmg.br) at Universidade Federal de Minas Gerais., (Copyright © 2022 Elsevier Ltd. All rights reserved.)- Published
- 2023
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27. Proposal of an algorithm to evaluate geometric distortion and artifact spreading in digital breast tomosynthesis.
- Author
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Cesário GJ, Paixão L, Santos R, Chevalier M, Attie MR, Nogueira MS, and Souza DN
- Subjects
- Algorithms, Aluminum, Humans, Mammography methods, Artifacts, Polymethyl Methacrylate
- Abstract
Background: According to the European Reference Organization for Quality Assurance Breast Screening and European Diagnostic Services, the spatial accuracy of reconstructed images and reconstruction artifacts must be evaluated in digital breast tomosynthesis (DBT) quality control procedures., Purpose: To propose a computational algorithm to evaluate the geometric distortion and artifact spreading (GDAS) in DBT images., Material and Methods: The proposed algorithm analyzed tomosynthesis images of a phantom that contains aluminum spheres (1 mm in diameter) arranged in a rectangular matrix spaced 5 cm apart that was inserted in 5-mm-thick polymethylmethacrylate (PMMA)., Results: The obtained results were compared with the values provided by the algorithm developed by the National Coordinating Center for the Physics of Mammography (NCCPM). In the comparison, the results depended on the dimensions of the region of interest (ROI). This dependence proves the benefit of the proposed algorithm because it allows the user to select the ROI., Conclusion: The computational algorithm proved to be useful for the evaluation of GDAS in DBT images, in the same way as the reference algorithm (NCCPM), as well as allowing the selection of the ROI dimensions that best suit the spreading of the artifact in the analyzed images.
- Published
- 2022
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28. Mapping of Brain Activity in the Analgesia Induced by Ph α 1 β and Morphine.
- Author
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Diniz DM, Malamut C, Araújo MR, Ferreira AV, Silva JF, Cordeiro MDN, Borges MH, Romano Silva MA, Gomez MV, and Castro Junior CJ
- Abstract
Preclinical evidence suggests the potential of Ph α 1 β , a toxin obtained from the venom of spider Phoneutria nigriventer , as a new analgesic drug. Molecular brain imaging techniques have afforded exciting opportunities to examine brain processes in clinical pain conditions. This paper aims to study the brain regions involved in the analgesic effects of Ph α 1 β compared with Morphine, in a model of acute pain induced by formalin in Sprague Dawley rats. We used
18 F-fluorodeoxyglucose as a metabolic radiotracer to perform brain imaging of rats pretreated with Ph α 1 β or Morphine in a model of acute inflammatory pain caused by intraplantar injection of formalin. The rats' hind paw's formalin stimulation resulted in a brain metabolic increase at the bilateral motor cortex, visual cortex, somatosensory cortex, thalamus, and cingulate cortex.In rats treated with Ph α 1 β , selective inhibition of unilateral motor cortex and cingulate cortex was observed. Morphine treatment leads to small and selective inhibition at the bilateral amygdala striatum and accumbens. Our results indicate that the analgesic effect of Ph α 1 β and Morphine possesses a differential profile of central processing in the pain state., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer (RMF) declared a shared affiliation, with one of the authors (MARS) to the handling editor at the time of the review., (Copyright © 2022 Diniz, Malamut, Araújo, Ferreira, Silva, Cordeiro, Borges, Romano Silva, Gomez and Castro Junior.)- Published
- 2022
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29. Radiolytic synthesis and characterization of selenium nanoparticles: comparative biosafety evaluation with selenite and ionizing radiation.
- Author
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Pereira AG, Gerolis LGL, Gonçalves LS, Moreira LMC, Gastelois PL, and Neves MJ
- Subjects
- Cell Survival drug effects, Metal Nanoparticles chemistry, Oxidative Stress, Saccharomyces cerevisiae drug effects, Saccharomyces cerevisiae metabolism, Sodium Selenite, Sulfhydryl Compounds, Containment of Biohazards, Nanoparticles chemistry, Radiation, Ionizing, Selenious Acid chemistry, Selenium chemistry
- Abstract
The goal of this work is use a green chemistry route to synthesize selenium nanoparticles (SeNPs) that do not trigger oxidative stress, typical of metallic, oxide metallic and carbonaceous nanostructures, and supply the same beneficial effects as selenium nanostructures. SeNPs were synthesized using a radiolytic method involving irradiating a solution containing sodium selenite (Se
4+ ) as the precursor in 1% Yeast extract, 2% Peptone, 2% Glucose (YPG) liquid medium with gamma-rays (60 Cobalt). The method did not employ any hazardous reducing agents. Saccharomyces cerevisiae cells were incubated with 1 mM SeNPs for 24 h and/or then challenged with 400 Gy of ionizing radiation were assessed for viability and biomarkers of oxidative stress: lipid peroxidation, protein carbonylation, free radical generation, and total sulfhydryl content. Spherical SeNPs with variable diameters (from 100 to 200 nm) were formed after reactions of sodium selenite with hydrated electrons (eaq - ) and hydrogen radicals (H·). Subsequent structural characterizations indicated an amorphous structure composed of elemental selenium (Se0 ). Compared to 1 mM selenite, SeNPs were considered safe and less toxic to Saccharomyces cerevisiae cells as did not elicit significant modifications in cell viability or oxidative stress parameters except for increased protein carbonylation. Furthermore, SeNPs treatment afforded some protection against ionizing radiation exposure. SeNPs produced using green chemistry attenuated the reactive oxygen species generation after in vitro ionizing radiation exposure opens up tremendous possibilities for radiosensitizer development., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)- Published
- 2022
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30. Quantification of soil erosion using 7 Be in a steep watershed used for natural grazing in Brazil.
- Author
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Esquivel AD, Moreira RM, Monteiro RPG, Rochido Dos Santos AA, Valladares DL, and Juri Ayub J
- Subjects
- Brazil, Rain, Soil chemistry, Beryllium analysis, Radioisotopes analysis, Soil Erosion
- Abstract
Cosmogenic
7 Be was used to evaluate soil loss in a mountainous micro-watershed near Belo Horizonte, Southwest Brazil. Two nearby sites were selected, a reference site in a flat area and an eroded site in a hill slope. At the reference site, soil samples were collected monthly throughout the year in order to evaluate seasonal variations of7 Be inventory in soil and its relation with the precipitation regime. Additionally, rainwater was collected and the expected7 Be soil content was predicted. At the reference site, the7 Be inventory shows seasonal variations, in accordance with the rainy season, and its distribution in the soil profile shows an exponential decrease in depth ( h0 = 6.9 ± 0.6 kg m-2 ; r2 = 0.97). At the eroded site, two soil sampling campaigns were performed in order to measure soil erosion in the watershed. The estimated net erosion was 42.2 ± 3.7 t ha-1 , indicating the loss of upper 5mm of soil per year. This corresponds to soil losses in the area in the range from moderate to severe erosion.- Published
- 2021
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31. Human Stem Cell-Derived Retinal Pigment Epithelial Cells as a Model for Drug Screening and Pre-Clinical Assays Compared to ARPE-19 Cell Line.
- Author
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Oliveira CR, Paiva MRB, Ribeiro MCS, Andrade GF, Carvalho JL, Gomes DA, Nehemy M, Fialho SL, Silva-Cunha A, and Góes AM
- Abstract
Background and Objectives: Eye diseases have a high socioeconomic impact on society and may be one of the fields in which most stem cell-related scientific accomplishments have been achieved recently. In this context, human Pluripotent Stem Cell (hPSC) technology arises as an important tool to produce and study human Embryonic Stem cell derived-Retinal Pigmented Epithelial Cells (hES-RPE) for several applications, such as cell therapy, disease modeling, and drug screening. The use of this technology in pre-clinical phases attends to the overall population desire for animal-free product development. Here, we aimed to compare hES-RPE cells with ARPE-19, one of the most commonly used retinal pigmented epithelial immortalized cell lines., Methods and Results: Functional, cellular and molecular data obtained suggest that hES-RPE cells more closely resembles native RPEs compared to ARPE-19. Furthermore, hES-RPE revealed an interesting robustness when cultured on human Bruch's membrane explants and after exposure to Cyclosporine (CSA), Sirolimus (SRL), Tacrolimus (TAC), Leflunomide (LEF) and Teriflunomide (TER). On these conditions, hES-RPE cells were able to survive at higher drug concentrations, while ARPE-19 cell line was more susceptible to cell death., Conclusions: Therefore, hES-RPEs seem to have the ability to incur a broader range of RPE functions than ARPE-19 and should be more thoroughly explored for drug screening.
- Published
- 2021
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32. Monte Carlo assessment of low energy electron range in liquid water and dosimetry effects.
- Author
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Seniwal B, Mendes BM, Malano F, Pérez P, Valente M, and Fonseca TCF
- Subjects
- Computer Simulation, Radiometry, Relative Biological Effectiveness, Electrons, Monte Carlo Method, Water
- Abstract
The effects of low energy electrons in biological tissues have proved to lead to severe damages at the cellular and sub-cellular level. It is due to an increase in the relative biological effectiveness (RBE) of these electrons with a decrease in their penetration range. That is, lower the range higher will be its RBE.Therefore, accurate determination of low energy electron range becomes a key issue for radiation dosimetry. This work reports on in-water electron tracks evaluated at low kinetic energy (1-50 keV) using isotropic mono-energetic point source approach suitably implemented by different general-purpose Monte Carlo codes. For this aim, simulations were performed using PENELOPE, EGSnrc, MCNP6, FLUKA and Geant4-DNA Monte Carlo codes to obtain the particle range, R,R
90 ,R50 . Finally, evaluation of dose point kernel (DPK), as used for internal dosimetry, was carried out as an application example. Scaled dose point kernels (sDPK) were estimated for a range of mono-energetic low energy electron sources. The non-negligible differences among the calculated sDPK using different codes were obtained for energy electrons up to 5 keV. It was also observed that differences of in-water range for low-energy electrons, due to the different general-purpose Monte Carlo codes, affected the DPKs used for dosimetry by convolution approach. Finally, the 3D dosimetry was found to be almost not affected at macroscopic clinical scale, whereas non-negligible differences appeared at the microscopic level. Hence, a thorough validation of the used sDPKs have to be performed before they could be used in applications to derive any conclusions., (Copyright © 2020 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)- Published
- 2020
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33. Metabolomic studies of amino acid analysis in Saccharomyces cells exposed to selenium and gamma irradiation.
- Author
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Batista JM, Neves MJ, Pereira AG, Gonçalves LS, Menezes HC, and Cardeal ZL
- Subjects
- Amino Acids analysis, Saccharomyces cerevisiae cytology, Selenium metabolism, Amino Acids metabolism, Gamma Rays, Metabolomics, Saccharomyces cerevisiae metabolism, Selenium chemistry
- Abstract
Metabolomic studies are essential to identify and quantify key metabolites in biological systems. Analysis of amino acids (AA) is very important in target metabolomics studies. Chromatographic methods are used to support metabolite determinations. Therefore, this work presents analysis of 17 AA in Saccharomyces cerevisiae cells (a useful model in the study of cancer metabolism) exposed to sodium selenite and gamma radiation. An improved GC/MS method using propyl chloroformate/propanol as derivatizing reagent was applied to AA determinations. The method exhibited good linearity in the range of 0.08-600.00 mg L
-1 ; limits of determination from 0.04 to 1.60 mg L-1 ; limits of quantification from 0.08 to 2.76 mg L-1 ; repeatability ranging from 1.9 to 11.4 %; and precision ranging from 2.8 to 13.8 %. The correlations between selenite/gamma radiation with AA profile was investigated to establish candidates for cancer biomarkers. The analyses of yeast cultures found high concentrations of amino acids, such as Alanine, Serine, Glutamate, and Lysine, which might be associated with the development of metabolic adaptations of cancer based on its high demand for biomass and energy, found both in this model and neoplastic cells., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Inc. All rights reserved.)- Published
- 2020
- Full Text
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34. Origin of spring waters employing a multiparametric approach with special focus on stable isotopes 2 H and 18 O in the Lagoa Santa Karst region, Southern Brazil.
- Author
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Ribeiro C, Velásquez L, and Fleming P
- Subjects
- Brazil, Hydrology, Tritium analysis, Water Resources, Deuterium analysis, Environmental Monitoring methods, Groundwater chemistry, Natural Springs chemistry, Oxygen Isotopes analysis
- Abstract
Karst environments have an inherent complexity that interferes with their hydrogeology comprehension. Hence, isotope hydrology can be a valuable tool to assess trajectory of subsurface flows in an unexplored setting. The study area is located in the Lagoa Santa Karst, an environmental protection area of great economic, cultural and ecological importance, where Neoproterozoic metalimestones accommodate karst-fractured aquifers, characterized by complex water dynamics, essential vulnerability and high productivity. The purpose of this study was to investigate groundwater flow origins of springs using principally environmental stable isotopes
2 H and18 O. Rainwater and spring water were sampled and analysed. The LMWL presents angular and linear coefficients strongly similar to those of the GMWL. Spring isotopic signatures, which represent the base flow and present wide-ranging of2 H and18 O, were separated into two groups. The first group can be associated with recent rainwater major contributions, while the second group shows significant evaporated water contributions, largely represented by resurgences. Tritium concentration and physico-chemical parameter data supported this interpretation, pointing that waters of the second group remained more time on the surface and subsurface. Therefore, using isotope tracers to evaluate upper groundwater zone in this tropical karst system is a powerful instrument for water resources management.- Published
- 2020
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- View/download PDF
35. ESTIMATION OF THE ANISOTROPY EMISSION OF LPN/CIEMAT NEUTRON SOURCES: EFFECT OF HEAVY CAPSULE HOLDERS.
- Author
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Villafañe RM, de Sousa Lacerda MA, Blanco XC, Sánchez FG, and Vega-Carrillo HR
- Subjects
- Anisotropy, Equipment Design, Humans, Radiation Dosage, Scattering, Radiation, Americium analysis, Californium analysis, Neutrons, Particle Accelerators instrumentation, Particle Accelerators standards, Radiation Protection standards
- Abstract
In order to estimate the anisotropy emission of 241Am-Be and 252Cf neutron sources from the Spanish Neutron Standards Laboratory (LPN/CIEMAT) detailed models of sources capsules and capsule holders were designed with the MCNPX code. Simulations of the sources inside the capsules without the capsule holders were done to validate the MC model by comparison with experimental results provided by other authors. After that, the capsule holders were incorporated to the simulation. In general, a good agreement has been found between measurements and our calculations. Results show the additional encapsulations have significant influence on anisotropy factors, energy spectra and dose rates., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2019
- Full Text
- View/download PDF
36. Boron nitride nanotube@NiFe 2 O 4 : a highly efficient system for magnetohyperthermia therapy.
- Author
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Cabral TC, Ardisson JD, de Miranda MC, Gomes DA, Fernandez-Outon LE, Sousa EM, and Ferreira TH
- Subjects
- Ferric Compounds chemistry, HeLa Cells, Humans, Nickel chemistry, Boron Compounds chemistry, Nanoparticles chemistry, Nanotechnology methods, Nanotubes chemistry
- Abstract
Aim: The field of nanotechnology promotes the development of innovative and more effective cancer therapies. This work is aimed to develop a hybrid system that combines the capacity of boron nitride nanotubes (BNNTs) to be internalized by tumor cells and the ability of nickel ferrite nanoparticles to efficiently release heat by induced AC magnetic heating. Materials & methods: The systems studied were characterized by using x-ray diffractometry, transmission electron microscopy, vibrating sample magnetometry and Mössbauer spectroscopy. Results: The ferrite nanoparticles attached to BNNT were able to achieve the required temperatures for magnetohyperthermia therapies. After cellular internalization, AC induced magnetic heating of BNNT@NiFe
2 O4 can kill almost 80% of Hela cells lineage in a single cycle. Conclusion: This system can be a highly efficient magnetohyperthermia agent in cancer therapy.- Published
- 2019
- Full Text
- View/download PDF
37. Microstructural Characterization of Porous Clay-Based Ceramic Composites.
- Author
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Freitas Dutra L, Freitas ME, Grillet AC, Mendes N, and Woloszyn M
- Abstract
Clay-based materials are the most traditional components of buildings. To improve their performance in a sustainable way, agents can be mixed to fired clay acting as a pore-forming factor. However, firing temperatures highly influence their microstructure which is closely linked to a material's final performance as a ceramic block. To highlight the influence of the firing temperature on microstructure, and more specifically on the pore size distribution of clay-based materials, three innovative porous materials were manufactured. These materials were produced by mixing clay and pore-forming agents. They were characterized by optical and scanning electronic microscopy, x-ray diffraction, mercury intrusion and nitrogen adsorption. These techniques allow the phase identification of materials, show sample microstructure and quantify the pore size distribution at different scales. Furthermore, geometric parameters of sample microstructure such as grain diameter and roundness are estimated by using computer software. To conclude, results provide an enlightenment about the influence of material microstructure on the pore size distribution at two firing temperatures. These results can be useful to allow the tune of porous characteristics and, therefore, contribute to the production of more sustainable construction materials.
- Published
- 2019
- Full Text
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38. Nanocrystalline Transition-Metal Gallium Oxide Spinels from Acetylacetonate Precursors via Solvothermal Synthesis.
- Author
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Cook DS, Kashtiban RJ, Krambrock K, de Lima GM, Stumpf HO, Lara LRS, Ardisson JD, and Walton RI
- Abstract
The synthesis of mixed-metal spinels based on substituted γ-Ga₂O₃ is reported using metal acetylacetonate precursors in solvothermal reactions with alcohols as solvents at 240 °C. New oxides of Cr, Mn and Fe have been produced, all of which are formed as nanocrystalline powders, as seen by high-resolution transmission electron microscopy (HR-TEM). The first chromium-gallium mixed oxide is thus formed, with composition
0.33 Ga1.87 Cr0.8 O₄ ( = vacant site). X-ray absorption near-edge spectroscopy (XANES) at the chromium K-edge shows the presence of solely octahedral Cr3+ , which in turn implies a mixture of tetrahedral and octahedral Ga3+ , and the material is stable on annealing to at least 850 °C. An analogous manganese material with average chemical composition close to MnGa₂O₄ is shown to contain octahedral Mn2+ , along with some Mn3+ , but a different inversion factor to materials reported by conventional solid-state synthesis in the literature, which are known to have a significant proportion of tetrahedral Mn2+ . In the case of iron, higher amounts of the transition metal can be included to give an Fe:Ga ratio of 1:1. Elemental mapping using energy dispersive X-ray spectroscopy on the TEM, however, reveals inhomogeneity in the distribution of the two metals. This is consistent with variable temperature57 Fe Mössbauer spectroscopy that shows the presence of Fe2+ and Fe3+ in more than one phase in the sample. Variable temperature magnetisation and electron paramagnetic resonance (EPR) indicate the presence of superparamagnetism at room temperature in the iron-gallium oxides.- Published
- 2019
- Full Text
- View/download PDF
39. Assessment of the effects of graphene exposure in Danio rerio: A molecular, biochemical and histological approach to investigating mechanisms of toxicity.
- Author
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Fernandes AL, Nascimento JP, Santos AP, Furtado CA, Romano LA, Eduardo da Rosa C, Monserrat JM, and Ventura-Lima J
- Subjects
- Animals, Brain metabolism, Gills metabolism, Glutathione metabolism, Glutathione Transferase metabolism, Graphite pharmacokinetics, Oxidative Stress drug effects, Tissue Distribution, Zebrafish metabolism, Glutamate-Cysteine Ligase metabolism, Graphite toxicity
- Abstract
Graphene has been shown to induce toxicity in mammals and marine crustaceans; however, information regarding oxidative stress in fish is scarce. The aim of this study was to evaluate the mechanism of graphene toxicity in different tissues of Danio rerio, considering different parameters of stress. Animals were injected intraperitoneally (i.p.) with 10 μL of suspensions containing different graphene concentrations (5 and 50 mg/L); the gills, intestine, muscle and brain were analysed 48 h later. There was no significant difference in the expression of the gclc (glutamate cysteine ligase catalytic subunit) and nrf2 (nuclear factor (erythroid-derived 2)-like 2) genes after exposure. In contrast, glutamate cysteine ligase (GCL) and glutathione-S-transferase (GST) activities were modulated and the glutathione (GSH) concentration was reduced in different tissues and at different concentrations. Lipid damage was observed in the gills. Histological analyses were performed to observe if the exposure could induce pathological damage in these tissues. The results showed pathological effects in all tissues, excluding the intestine, after exposure to both concentrations. Overall, these results indicate that graphene induces different grades of toxicological effects that are dependent on the analysed organ, with distinct pathological effects on some and oxidative effects on others. However, the brain and gills seem to be the primary target organs for graphene toxicity., (Copyright © 2018. Published by Elsevier Ltd.)
- Published
- 2018
- Full Text
- View/download PDF
40. Very sensitive α-Al 2 O 3 :C polycrystals for thermoluminescent dosimetry.
- Author
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Fontainha CCP, Alves N, Ferraz WB, and de Faria LO
- Abstract
New materials have been widely investigated for ionizing radiation dosimetry for medical procedures. Carbon-doped alumina (α-Al
2 O3 :C) have been reported to be excellent thermoluminescent (TL) and optically stimulated luminescence (OSL) radiation dosimeters. In the present study, we have synthetized nano and micro-sized α-Al2 O3 :C polycrystals, doped with different percentages of carbon atoms aiming to compare their efficiency as TL dosimeters. The dosimetric characteristics for X ray and gamma fields were investigated. Samples doped with different amounts of carbon atoms were sintered under different atmosphere conditions, at temperatures ranging from 1300 °C to 1750 °C. Among the investigated samples, the micro-sized alumina doped with 0.01% of carbon and sintered at 1700 °C under reducing atmosphere, has presented a very high TL output. The main TL peak is centered at 250 °C and has a linear behavior with photon dose in the dose range of 0.02-to-5000 mGy, with correlation coefficient very close to one (0.99991). Samples produced by using nanosized alumina have shown much lower TL output when compared to the samples with microsized alumina. The micro-sized alumina obtained by the methodology used in this work is a suitable candidate to be explored for application in X and Gamma radiation dosimetry., (Copyright © 2018 Elsevier Ltd. All rights reserved.)- Published
- 2018
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- View/download PDF
41. Cardiac risk and MCNP/SISCODES doses in RT of the left internal mammary chain with photon and electron portals.
- Author
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Campos TPR, Mendes BM, Trindade B, and Araujo WL
- Abstract
Aim: The present study evaluated the increment of cardiac risk (CR) and absorbed dose in radiotherapy of the internal mammary chain (IMC), in particular with photon portals of 4 6 MV, and cobalt therapy (Co60); and, electron portals of 8, 12 and 16 MeV applied in the left breast, considering the adoption of a combined photon (16 Gy) and electron (30 Gy) protocols., Materials and Methods: The modified ICRP-reference female model of 60 kg, 163 cm and 43 years of age, coil RCP-AF, was modelled. The MCNP6/SICODES codes were employed, where the spatial dose distributions and dose-volume histograms were generated. Toxicity limits and a CR model were considered., Results: CR associated with the 6 MV, 4 MV and Co60 portals increased 41.1; 40.6 and 34.5%, respectively; while, in 8, 12 and 16 MeV portals, they were 5.0, 32.5 and 49.2%, respectively. High anomalous scatter radiation from electron portals was found in the left lung providing an average dose of 3.3-5.0 Gy., Conclusions: To RCP-AF, the Co60 portal for IMC-RT presented more attractive dose distribution, whose 16 Gy for photon-component produced less CR increase, 5% lower than the other photon portals. Considering electron portals, the smallest CR increase was produced by 8 MeV portal while 12-16 MeV made the risk higher. There is a call for a less hardened energetic spectrum in order to reduce CR; however, holding suitable IMC penetration. A combined Co60/8-12 MeV may bring benefits, reducing CR. The lowest risk was found to 46 Gy electron portals exclusively.
- Published
- 2018
- Full Text
- View/download PDF
42. New Radiation Dosimetry Estimates for [ 18 F]FLT based on Voxelized Phantoms.
- Author
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Mendes BM, Ferreira AV, Nascimento LTC, Ferreira SMZMD, Silveira MB, and Silva JB
- Subjects
- Animals, Female, Humans, Male, Mice, Phantoms, Imaging, Tissue Distribution, Dideoxynucleosides pharmacokinetics, Radiometry instrumentation
- Abstract
3'-Deoxy-3-[
18 F]fluorothymidine, or [18 F]FLT, is a positron emission tomography (PET) tracer used in clinical studies for noninvasive assessment of proliferation activity in several types of cancer. Although the use of this PET tracer is expanding, to date, few studies concerning its dosimetry have been published. In this work, new [18 F]FLT dosimetry estimates are determined for human and mice using Monte Carlo simulations. Modern voxelized male and female phantoms and [18 F]FLT biokinetic data, both published by the ICRP, were used for simulations of human cases. For most human organs/tissues the absorbed doses were higher than those reported in ICRP Publication 128. An effective dose of 1.70E-02 mSv/MBq to the whole body was determined, which is 13.5% higher than the ICRP reference value. These new human dosimetry estimates obtained using more realistic human phantoms represent an advance in the knowledge of [18 F]FLT dosimetry. In addition, mice biokinetic data were obtained experimentally. These data and a previously developed voxelized mouse phantom were used for simulations of animal cases. Concerning animal dosimetry, absorbed doses for organs/tissues ranged from 4.47 ± 0.75 to 155.74 ± 59.36 mGy/MBq. The obtained set of organ/tissue radiation doses for healthy Swiss mice is a useful tool for application in animal experiment design.- Published
- 2018
- Full Text
- View/download PDF
43. Replacement of soybean oil by fish oil increases cytosolic lipases activities in liver and adipose tissue from rats fed a high-carbohydrate diets.
- Author
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Rodrigues AH, Moreira CCL, Neves MJ, Botion LM, and Chaves VE
- Subjects
- Adipocytes enzymology, Animal Feed, Animals, Cytosol enzymology, Disease Models, Animal, Epididymis metabolism, Fructose adverse effects, Glucose Tolerance Test, Hydrolysis, Insulin chemistry, Lipid Metabolism, Lipogenesis, Lipoprotein Lipase metabolism, Lipoproteins, VLDL metabolism, Male, Non-alcoholic Fatty Liver Disease metabolism, Phosphorylation, Rats, Rats, Wistar, Triglycerides chemistry, Triglycerides metabolism, Adipose Tissue enzymology, Dietary Carbohydrates administration & dosage, Fish Oils administration & dosage, Lipase metabolism, Liver enzymology, Soybean Oil administration & dosage
- Abstract
Several studies have demonstrated that fish oil consumption improves metabolic syndrome and comorbidities, as insulin resistance, nonalcoholic fatty liver disease, dyslipidaemia and hypertension induced by high-fat diet ingestion. Previously, we demonstrated that administration of a fructose-rich diet to rats induces liver lipid accumulation, accompanied by a decrease in liver cytosolic lipases activities. In this study, the effect of replacement of soybean oil by fish oil in a high-fructose diet (FRUC, 60% fructose) for 8 weeks on lipid metabolism in liver and epididymal adipose tissue from rats was investigated. The interaction between fish oil and FRUC diet increased glucose tolerance and decreased serum levels of triacylglycerol (TAG), VLDL-TAG secretion and lipid droplet volume of hepatocytes. In addition, the fish oil supplementation increased the liver cytosolic lipases activities, independently of the type of carbohydrate ingested. Our results firmly establish the physiological regulation of liver cytosolic lipases to maintain lipid homeostasis in hepatocytes. In epididymal adipose tissue, the replacement of soybean oil by fish oil in FRUC diet did not change the tissue weight and lipoprotein lipase activity; however, there was increased basal and insulin-stimulated de novo lipogenesis and glucose uptake. Increased cytosolic lipases activities were observed, despite the decreased basal and isoproterenol-stimulated glycerol release to the incubation medium. These findings suggest that fish oil increases the glycerokinase activity and glycerol phosphorylation from endogenous TAG hydrolysis. Our findings are the first to show that the fish oil ingestion increases cytosolic lipases activities in liver and adipose tissue from rats treated with high-carbohydrate diets., (Copyright © 2018. Published by Elsevier Inc.)
- Published
- 2018
- Full Text
- View/download PDF
44. Theoretical and Experimental Studies of the Controlled Release of Tetracycline Incorporated into Bioactive Glasses.
- Author
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Andrade ÂL, Militani IA, de Almeida KJ, Belchior JC, Dos Reis SC, Costa E Silva RMF, and Domingues RZ
- Subjects
- Anti-Bacterial Agents administration & dosage, Anti-Bacterial Agents chemical synthesis, Anti-Bacterial Agents pharmacokinetics, Delayed-Action Preparations administration & dosage, Delayed-Action Preparations chemical synthesis, Delayed-Action Preparations pharmacokinetics, Diffusion, Drug Compounding methods, Freeze Drying methods, Spectroscopy, Fourier Transform Infrared methods, Tetracyclines administration & dosage, Tetracyclines pharmacokinetics, Drug Delivery Systems methods, Drug Liberation, Tetracyclines chemical synthesis
- Abstract
Several authors have studied the release profile of drugs incorporated in different devices. However, to the best of our knowledge, although many studies have been done on the release of tetracycline, in these release devices, no study has investigated if the released compound is actually the tetracycline, or, instead, a degraded product. This approach is exploited here. In this work, we analyse the influence of two drying methods on the tetracycline delivery behaviour of synthesised glasses using the sol-gel process. We compare the drying methods results using both theoretical models and practical essays, and analyse the chemical characteristic of the released product in order to verify if it remains tetracycline. Samples were freeze-dried or dried in an oven at 37°C and characterised by several methods such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TG), differential thermogravimetric analysis (DTG), differential thermal analyses (DTA) and gas adsorption analysis (BET). The released concentration of tetracycline hydrochloride was studied as a function of time, and it was measured by ultraviolet spectrophotometry in the tetracycline wavelength. The drug delivery profiles were reasonably consistent with a diffusion model analysis. In addition, we observed higher release rates for the freeze-dried compared to those dried in an oven at 37°C. This higher release can be attributed to larger pore size for the freeze-dried sample systems with tetracycline, which promoted more water penetration, improving the drug diffusion. The analysis of the solution obtained in the release tests using high-performance liquid chromatography- mass spectrometry (HPLC-MS) confirmed that tetracycline was being released.
- Published
- 2018
- Full Text
- View/download PDF
45. Surface restructuring of red mud to produce FeO x (OH) y sites and mesopores for the efficient complexation/adsorption of β-lactam antibiotics.
- Author
-
Pinto PS, Lanza GD, Souza MN, Ardisson JD, and Lago RM
- Subjects
- Adsorption, Aluminum Oxide, Industrial Waste, Metallurgy, Amoxicillin chemistry, Anti-Bacterial Agents chemistry, Ceftriaxone chemistry, Cephalexin chemistry, Ferrous Compounds chemistry
- Abstract
In this work, iron oxide in the red mud (RM) waste was restructured to produce mesopores with surface [FeO
x (OH)y ] sites for the efficient complexation/adsorption of β-lactam antibiotics. Red mud composed mainly by hematite was restructured by an acid/base process followed by a thermal treatment at 150-450 °C (MRM150, MRM200, MRM300, and MRM450) and fully characterized by Mössbauer, XRD, FTIR, BET, SEM, CHN, and thermogravimetric analyses. The characterization data showed a highly dispersed Fe3+ oxyhydroxy phase, which was thermally dehydrated to a mesoporous α-Fe2 O3 with surface areas in the range of 141-206 m2 g-1 . These materials showed high efficiencies (21-29 mg g-1 ) for the adsorption of β-lactam antibiotics, amoxicillin, cephalexin, and ceftriaxone, and the data was better fitted by the Langmuir model isotherm (R2 = 0.9993) with monolayer adsorption capacity of ca. 39 mg g-1 for amoxicillin. Experiments such as competitive adsorption in the presence of phosphate and H2 O2 decomposition suggested that the β-lactamic antibiotics might be interacting with surface [FeOx (OH)y ] species by a complexation process. Moreover, the OH/Fe ratio, BET surface area and porosity indicated that this complexation is occurring especially on [FeOx (OH)y ]surf sites contained in the mesopore space.- Published
- 2018
- Full Text
- View/download PDF
46. Assessment of radiation-induced secondary cancer risk in the Brazilian population from left-sided breast-3D-CRT using MCNPX.
- Author
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Mendes BM, Trindade BM, Fonseca TCF, and de Campos TPR
- Subjects
- Female, Humans, Phantoms, Imaging, Radiation Dosage, Radiometry, Radiotherapy Dosage, Radiotherapy, Conformal adverse effects, Radiotherapy, Conformal methods, Risk Assessment, Risk Factors, Neoplasms, Radiation-Induced etiology, Neoplasms, Second Primary etiology, Unilateral Breast Neoplasms radiotherapy
- Abstract
Objective: The aim of this work was to simulate a 6MV conventional breast 3D conformational radiation therapy (3D-CRT) with physical wedges (50 Gy/25#) in the left breast, calculate the mean absorbed dose in the body organs using robust models and computational tools and estimate the secondary cancer-incidence risk to the Brazilian population., Methods: The VW female phantom was used in the simulations. Planning target volume (PTV) was defined in the left breast. The 6MV parallel-opposed fields breast-radiotherapy (RT) protocol was simulated with MCNPx code. The absorbed doses were evaluated in all the organs. The secondary cancer-incidence risk induced by radiotherapy was calculated for different age groups according to the BEIR VII methodology., Results: RT quality indexes indicated that the protocol was properly simulated. Significant absorbed dose values in red bone marrow, RBM (0.8 Gy) and stomach (0.6 Gy) were observed. The contralateral breast presented the highest risk of incidence of a secondary cancer followed by leukaemia, lung and stomach. The risk of a secondary cancer-incidence by breast-RT, for the Brazilian population, ranged between 2.2-1.7% and 0.6-0.4%., Conclusion: RBM and stomach, usually not considered as OAR, presented high second cancer incidence risks of 0.5-0.3% and 0.4-0.1%, respectively. This study may be helpful for breast-RT risk/benefit assessment. Advances in knowledge: MCNPX-dosimetry was able to provide the scatter radiation and dose for all body organs in conventional breast-RT. It was found a relevant risk up to 2.2% of induced-cancer from breast-RT, considering the whole thorax organs and Brazilian cancer-incidence.
- Published
- 2017
- Full Text
- View/download PDF
47. New source models to represent the irradiation process in panoramic gamma irradiator.
- Author
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Gual MR, Milian FM, Mesquita AZ, and Pereira C
- Abstract
The use of gamma irradiation technologies generates a number of complex scientific and technical problems; for example, the target is manually loaded onto turntables and is rotated during the entire irradiation process and the MCNPX three-dimensional geometry simulation is kept static. For this, it is necessary to introduce additional approaches. In this paper, two new methodologies are proposed for the simulation of irradiation process in panoramic gamma irradiator. The study was performed at the gamma irradiation facility at the Nuclear Technology Development Center of the National Nuclear Energy Commission, Brazil. The source can be reproduced with a homogenized geometry. Validation of MCNPX calculations of gamma doses were performed by thorough comparison with the experimental measurements. The contribution of this proposed source models has opened new lines of research. The results of this study showed that the proposed source models effectively represent the irradiation process., (Copyright © 2017 Elsevier Ltd. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
48. Wet deposition and soil content of Beryllium - 7 in a micro-watershed of Minas Gerais (Brazil).
- Author
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Esquivel L AD, Moreira RM, Monteiro RPG, Dos Santos AAR, Juri Ayub J, and Valladares DL
- Subjects
- Brazil, Rain, Water Movements, Beryllium analysis, Radiation Monitoring, Radioisotopes analysis, Soil chemistry
- Abstract
Beryllium-7 (
7 Be) is a natural radionuclide of cosmogenic origin, normally used as a tracer for several environmental processes; such as soil redistribution, sediment source discrimination, atmospheric mass transport, and trace metal scavenging from the atmosphere. In this research the content of7 Be in soil, its seasonal variation throughout the year and its relationship with the rainfall regime in the Mato Frio creek micro-watershed was investigated, to assess its potential use in estimating soil erosion. The7 Be content in soil shows a marked variation throughout the year. Minimum7 Be values were observed in the dry season (from April to September) and were between 7 and 14 times higher in the rainy season (from October to March). The seasonal oscillations in7 Be soil content could be explained by the asymmetric rainfall regime. A highly linear relationship between rainfall amount and7 Be deposition was observed in rain water. A good agreement between7 Be soil content and7 Be atmospheric deposition was noticed, mainly in wet months.7 Be penetration in soil reaches a 5 cm depth, this could be explained by the soil type in the region. The soils are Acrisol type, characterized by low pH values and clay illuviation in deeper layers of the soil. In some regions of Brazil special attention should be paid if this radionuclide will be used as soil erosion tracer, taking into account the soil origin and its particular properties., (Copyright © 2017 Elsevier Ltd. All rights reserved.)- Published
- 2017
- Full Text
- View/download PDF
49. Exposure to few-layer graphene through diet induces oxidative stress and histological changes in the marine shrimp Litopenaeus vannamei .
- Author
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Fernandes AL, Josende ME, Nascimento JP, Santos AP, Sahoo SK, da Silva FMR Júnior, Romano LA, Furtado CA, Wasielesky W, Monserrat JM, and Ventura-Lima J
- Abstract
The production and use of graphene-based nanomaterials is rapidly increasing. However, few data are available regarding the toxicity of these nanomaterials in aquatic organisms. In the present study, the toxicity of few-layer graphene (FLG) (obtained by chemical exfoliation) was evaluated in different tissues of the shrimp Litopenaeus vannamei following exposure to FLG through a diet for four weeks. Transmission electron microscopy and dynamic light scattering measurements showed a distribution of lateral sheet sizes between 100 and 2000 nm with the average length and width of 800 and 400 nm, respectively. Oxidative stress parameters were analyzed, indicating that FLG exposure led to an increase in the concentration of reactive oxygen species, modulated the activity of antioxidant enzymes such as glutamate cysteine ligase and glutathione- S -transferase, and reduced glutathione levels and total antioxidant capacity. However, the observed modulations were not sufficient to avoid lipid and DNA damage in both gill and hepatopancreas tissues. Furthermore, graphene exposure resulted in morphological changes in hepatopancreas tissues. These results demonstrate that exposure to FLG through the diet induces alterations in the redox state of cells, leading to a subsequent oxidative stress situation. It is therefore clear that nanomaterials presenting these physico-chemical characteristics may be harmful to aquatic biota.
- Published
- 2016
- Full Text
- View/download PDF
50. Role of [FeOx(OH)y] surface sites on the adsorption of β-lactamic antibiotics on Al2O3 supported Fe oxide.
- Author
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Pinto PS, Medeiros TPV, Ardisson JD, and Lago RM
- Subjects
- Adsorption, Surface Properties, Aluminum Oxide chemistry, Anti-Bacterial Agents analysis, Ferric Compounds chemistry, Wastewater chemistry, Water Purification, beta-Lactams analysis
- Abstract
In this work, [FeOx(OH)y]/Al2O3 composites with different Fe oxyhydroxy contents, i.e. 10, 20 and 50wt% treated at 150, 200, 300 and 450°C were investigated as adsorbents of β-lactamic antibiotics, i.e. cephalexin, ceftriaxone and especially amoxicillin, from aqueous solutions. The obtained results showed that the nature of the surface Fe(3+) species play a fundamental role on the adsorption process. The most efficient adsorption was obtained for the sample 150Fe50A (50% [FeOx(OH)y] supported in Al2O3 treated at 150°C) whereas the thermal treatment at higher temperatures caused a strong decrease on the adsorption capacity. Mössbauer, XRD, FTIR, Raman, TG-MS, SEM, CHN and BET of the composite 150Fe50A suggested an approximate composition of FeO0.65(OH)1.7 whereas at 450°C strong dehydroxylation process takes place to form FeO1.4(OH)0.21. These results combined with competitive adsorption using amoxicillin mixed with phosphate or H2O2 suggest that the antibiotic molecules adsorb by complexation on surface sites likely based on FeOx(OH)y by the replacement of the labile OH ligands., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
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