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Aplicabilidade de sílica mesoporosa ordenada como adjuvante imunológico; Applicability of ordered mesoporous silica as immunologic adjuvant

Mariano Neto, Francisco
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/09/2008 PT
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49.52056%
Este trabalho consistiu numa avaliação, sob um ponto de vista físico, da aplicabilidade da sílica mesoporosa ordenada tipo SBA-15 como adjuvante imunológico. Inicialmente foi estudado o método de preparação e reprodutibilidade das propriedades do material, condição necessária para a síntese de grandes quantidades (N 100g). Mostrou-se que a calcinação em vácuo, comparada com o processo em N2 e ar, resulta em material com estrutura mesoporosa mais bem ordenada. Para aplicações biológicas foi analisado o potencial de encapsulação de antígerios no material, através de estudos de incorporação de Albumina Bovina (BSA) e vacina contra Hepatite A. Foi observada uma incorporação bem-sucedida de BSA na sílica, com essa proteína alojando-se dentro da estrutura de poros. Resultado semelhante foi observado para a vacina contra hepatite A. O processo mais eficiente de incorporação foi determinado para uma mistura em repouso e seca através de evaporação. A aplicabilidade da sílica como adjuvante para uso animal foi avaliada através de análises, pelo método PIXE, da acumulação do material no organismo de camundongos. A sílica foi administrada a camundongos Swiss por via oral e intra-muscular, e o teor de silício em diferentes órgáos foi comparado aos teores em um grupo controle. Foi detectada a presença de sílica em determinados órgãos dos camundongos...

Síntese e análise da sílica mesoporosa SBA-15 para incorporação de moléculas; Synthesis and analysis of mesoporous silica SBA-15 for incorporation of molecules

Garcia, Paulo Ricardo de Abreu Furtado
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/03/2015 PT
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29.043394%
Neste trabalho estudou-se a encapsulação de proteínas com diferentes pesos moleculares na sílica mesoporosa ordenada SBA-15 para avaliar sua aplicação como adjuvante imunológico. Para tanto, as proteínas IgG (150 kDa) e BSA (66,5 kDa) foram incorporadas à sílica mesoporosa com poros expandidos. Primeiramente estudou-se a dilatação dos poros utilizando-se um agente dilatador de estrutura no processo de síntese, através da preparação de amostras com diferentes quantidades de triisopropilbenzeno (TIPB). Resultados de isoterma de adsorção de nitrogênio (NAI) e espalhamento de raios X a baixo ângulo (SAXS) revelaram um aumento no diâmetro médio de poros da ordem de 23% e uma rede de poros mais desordenada. Para se ter uma estimativa das dimensões das proteínas, medidas de SAXS foram feitas e indicaram que ambas têm dimensões que permitiriam sua incorporação nos poros da SBA-15. As amostras com poros dilatados foram então utilizadas para a incorporação das proteínas IgG e BSA em solução tampão fosfato salina (PBS). Os resultados indicaram o preenchimento dos microporos pela solução de PBS com valor superior a 95%. Quanto ao preenchimento de mesoporos, observou-se maior variação no volume de poros e área superficial...

A COMBINED MULTI-ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH-WEST IBERIA: SYNCHROTRON m-XRF, EXTERNAL-PIXE/PIGE AND BSEM–EDS

Carneiro, André; Schiavon, N; Candeias, A; Ferreira, T; Calligaro, T; Lopes, C; Mirão, J
Fonte: Archaeometry Publicador: Archaeometry
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
28.033105%
An integrated, multi-analytical approach combining the high sensitivity of SR-mXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples (first to fourth centuries AD) from an important, but scarcely investigated, Roman region of south-west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a produc- tion technique common to Roman glasses throughout the Empire—that is, a silica-soda-lime low-Mg, low-K composition, with glass additives as colouring and/or decolouring agents (Fe, Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti-rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic-type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K-rich soils derived from the alteration of 2:1 clays in K-bearing rock sequences.

A COMBINED MULTI-ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH-WEST IBERIA: SYNCHROTRON micro-XRF, EXTERNAL-PIXE/PIGE AND BSEM–EDS

SCHIAVON, N.; CANDEIAS, A.; FERREIRA, T.; LOPES, M. DA CONCEIÇAO; CARNEIRO, A.; CALLIGARO, T.; MIRAO, J.
Fonte: wiley Publicador: wiley
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
38.328494%
An integrated, multi-analytical approach combining the high sensitivity of SR-mXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples(first to fourth centuries AD) from an important, but scarcely investigated, Roman region of south-west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a production technique common to Roman glasses throughout the Empire—that is, a silica-soda-lime low-Mg, low-K composition, with glass additives as colouring and/or decolouring agents (Fe,Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti-rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic-type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K-rich soils derived from the alteration of 2:1 clays in K-bearing rock sequences.

Co-localization of iron binding on silica with p62/sequestosome1 (SQSTM1) in lung granulomas of mice with acute silicosis

Shimizu, Yasuo; Dobashi, Kunio; Nagase, Hiroyuki; Ohta, Ken; Sano, Takaaki; Matsuzaki, Shinichi; Ishii, Yoshiki; Satoh, Takahiro; Koka, Masashi; Yokoyama, Akihito; Ohkubo, Takeru; Ishii, Yasuyuki; Kamiya, Tomihiro
Fonte: the Society for Free Radical Research Japan Publicador: the Society for Free Radical Research Japan
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
28.350623%
The cellular mechanisms involved in the development of silicosis have not been fully elucidated. This study aimed to examine influence of silica-induced lung injury on autophagy. Suspensions of crystalline silica particles were administered transnasally to C57BL/6j mice. Immunohistochemical examination for Fas and p62 protein expression was performed using lung tissue specimens. Two-dimensional and quantitative analysis of silica deposits in the lungs were performed in situ using lung tissue sections by an in-air microparticle induced X-ray emission (in-air micro-PIXE) analysis system, which was based on irrradiation of specimens with a proton ion microbeam. Quantitative analysis showed a significant increase of iron levels on silica particles (assessed as the ratio of Fe relative to Si) on day 56 compared with day 7 (p<0.05). Fas and p62 were expressed by histiocytes in granulomas on day 7, and the expressions persisted for day 56. Fas- and p62-expressing histiocytes were co-localized in granulomas with silica particles that showed an increase of iron levels on silica particles in mouse lungs. Iron complexed with silica induces apoptosis, and may lead to dysregulations of autophagy in histiocytes of granulomas, and these mechanisms may contribute to granuloma development and progression in silicosis.

On the influence of silica type on the structural integrity of dense La9.33Si2Ge4O26 electrolytes for SOFCs

Alves, Cátia; Marcelo, Teresa; Oliveira, F. A. Costa; Alves, L. C.; Mascarenhas, João; Trindade, B.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
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28.020833%
Apatite-type rare earth based oxides, such as R-doped lanthanum oxides of general formula La9.33(RO4)6O2 with R = Ge, Si, exhibit high ionic conductivity and low activation energy at moderate temperatures, when compared to the yttria-stabilized zirconia electrolyte making them potential materials to be used in the range 500–700 °C, for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this study, dense oxyapatite-based La9.33Si2Ge4O26 electrolytes have been successfully prepared either by electrical sintering at 1400 °C or microwave hybrid sintering at 1350 °C for 1 h from La2O3, SiO2 and GeO2 powders dry milled at 350 rpm for 15 h in a planetary ball mill. The densification behaviour of the apatite-type phase synthesized by mechanical alloying was found to be dependent on the grade of SiO2 used: either pre-milled quartz powder or amorphous nanosized fumed silica. The influence of the silica type on the La9.33Si2Ge4O26 integrity was assessed by dynamic Young's modulus, microhardness and indentation fracture toughness measurements. A good correlation between the degree of densification (as observed by SEM/EDS) and the resulting mechanical properties could be established. Pre-milling of quartz powder has favoured higher densification rates to be attained suggesting that both Fe content...

Thorium in high-titania slag

Nell,J.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
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18.350623%
Radioactive elements associated with heavy mineral deposits may be removed from the ilmenite concentrate before smelting or, alternatively, from the high-titanium slag after smelting. Either way, the radioactivity removal process will involve leaching and/or flux-roasting. However, the volume of slag is approximately 50 per cent less than the volume of ilmenite concentrate and it may therefore be more efficient to remove radioactive elements from the slag. Several slags with different compositions (in terms of iron to titanium ratio, silica content and radio activity) were studied. All the slags contain iron-titanium oxide phases with M3O5 (M = Fe2+, Ti3+, Ti4+, Mg2+, Al2+, Cr3+) stoichiometry, silicate phases and a small amount of entrained metal droplets. The silicate phases have variable compositions; in all the samples it was found that droplets of a silica-rich phase (containing about 60% SiO2) unmixes from a low-silica phase (containing about 40% SiO2). Both the highand low-silica phases are considered to be glass, representing quenched, immiscible silicate melt phases. The silicate and oxide phases were analysed by electron microprobe to determine the distribution of thorium in the slag (the concentrations of the radioactive daughter products of the thorium decay series are too low to be detected with the microbeam analytical facilities that were available during the investigation). The results are unequivocal: the concentration of thorium in M3O5 oxide phases is below the detection limit of the technique (500 ppm) while the concentration in the silicate phases is at the one per cent level. Furthermore...