987 resultados para 100-625B
Resumo:
One of the desired properties for any new biomaterial composition is its long-term stability in a suitable animal model and such property cannot be appropriately assessed by performing short-term implantation studies. While hydroxyapatite (HA) or bioglass coated metallic biomaterials are being investigated for in vivo biocompatibility properties, such study is not extensively being pursued for bulk glass ceramics. In view of their inherent brittle nature, the implant stability as well as impact of long-term release of metallic ions on bone regeneration have been a major concern. In this perspective, the present article reports the results of the in vivo implantation experiments carried out using 100% strontium (Sr)-substituted glass ceramics with the nominal composition of 4.5 SiO2-3Al(2)O(3)-1.5P(2)O(5)-3SrO-2SrF(2) for 26 weeks in cylindrical bone defects in rabbit model. The combination of histological and micro-computed tomography analysis provided a qualitative and quantitative understanding of the bone regeneration around the glass ceramic implants in comparison to the highly bioactive HA bioglass implants (control). The sequential polychrome labeling of bone during in vivo osseointegration using three fluorochromes followed by fluorescence microscopy observation confirmed homogeneous bone formation around the test implants. The results of the present study unequivocally confirm the long-term implant stability as well as osteoconductive property of 100% Sr-substituted glass ceramics, which is comparable to that of a known bioactive implant, that is, HA-based bioglass. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1168-1179, 2015.
Resumo:
Gas discharge plasmas used for thinfilm deposition by plasma-enhanced chemical vapor deposition (PECVD) must be devoid of contaminants, like dust or active species which disturb the intended chemical reaction. In atmospheric pressure plasma systems employing an inert gas, the main source of such contamination is the residual air inside the system. To enable the construction of an atmospheric pressure plasma (APP) system with minimal contamination, we have carried out fluid dynamic simulation of the APP chamber into which an inert gas is injected at different mass flow rates. On the basis of the simulation results, we have designed and built a simple, scaled APP system, which is capable of holding a 100 mm substrate wafer, so that the presence of air (contamination) in the APP chamber is minimized with as low a flow rate of argon as possible. This is examined systematically by examining optical emission from the plasma as a function of inert gas flow rate. It is found that optical emission from the plasma shows the presence of atmospheric air, if the inlet argon flow rate is lowered below 300 sccm. That there is minimal contamination of the APP reactor built here, was verified by conducting an atmospheric pressure PECVD process under acetylene flow, combined with argon flow at 100 sccm and 500 sccm. The deposition of a polymer coating is confirmed by infrared spectroscopy. X-ray photoelectron spectroscopy shows that the polymer coating contains only 5% of oxygen, which is comparable to the oxygen content in polymer deposits obtained in low-pressure PECVD systems. (C) 2015 AIP Publishing LLC.
Resumo:
The growth of highly lattice-mismatched InAs0.3Sb0.7 films on (100) GaAs Substrates by magnetron Sputtering has been investigated and even epitaxial lnAs(0.3)Sb(0.7) films have been successfully obtained. A strong effect of the growth conditions on the film structure was observed, revealing that there was a growth mechanism transition from three-dimensional nucleation growth to epitaxial layer-by-layer growth mode when increasing the substrate temperature. A qualitative explanation for that transition was proposed and the critical conditions for the epitaxial layer-by-layer growth mode were also discussed.
Resumo:
Resumen: El artículo traza un recorrido histórico a través de las cifras de la economía argentina, para mostrar los excesos de la política nacional durante lo s últimos ochenta años. La primera parte refleja la política proteccionista de las primeras décadas del siglo veinte. Luego, el autor expone los motivos que llevaron a la desmonetización de la economía, así como también al desarrollo del Estado empresario. Más adelante, el artículo presenta las distintas medidas adoptadas por el Estado, que condujeron a la pérdida de institucionalidad en nuestro país. Finalmente, el autor presenta diez agujeros negros de la economía argentina los cuales, en su opinión, frenaron el progreso de la nación, y propone analizar la historia desde esta perspectiva para evitar incurrir en los errores del pasado.
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Contenido: Sapientia, Veinticinco años después / Octavio N. Derisi – Tomás de Aquino, peregrino de Dios / Adolfo Muñoz Alonso – Qu’est-ce que la philosophie? / A. Dondeyne – La subordinación de la lógica a la ciencia / A. Furlán – Volición y voluntad en Aristóteles / B. Raffo Magnasco – Entendement et imagination selon Aristote / A. Guy – Le problème de l’existence de Dieu dans le Commentaire de Saint Thomas sur la Physique d’Aristote / F. Van Steenberghen – Individuación, analogía y participación en el plano físico / J. E. Bolzán – La “Summa Physicorum” y la filosofía natural de Grosseteste / C. Lértora Mendoza – El infinito actual en Santo Tomás / O. Argerami – Tomás de Aquino en la Universidad de París / G. E. Ponferrada – Dante y la filosofía / G. Terán – El ámbito del objeto de la fenomenología en E. Husserl / O. N. Derisi – Orígenes doctrinales de la Tercera Escolástica en la filosofía argentina del siglo XIX / A. Caturelli – Hegel e Cristo / C. Fabro – Sapientia reconsidered / A. G. M. Van Melsen – El punto de partida de la metafísica : ¿abstracción o intuición? / J. R. Sanabria – La catégorie hégélienne de contradiction / R. Verneaux – La ontología modificada / C. A. Iturralde Colombres – L’acte moral et le sujet / J. de Finance – La crítica de Monseñor Derisi a la ciencia política empírica / A. E. Sampay – Notas y comentarios -- Bibliografía
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El ensayo se estableció en las áreas de la Universidad Nacional Agraria, ubicada en Managua km 12 ½ carretera norte, en los meses comprendido de febrero-mayo del año dos mil doce, para evaluar efecto de diferentes láminas de riego y momentos de aplicación de 100 kg. ha-1 de nitrógeno, sobre el crecimiento del maíz (Zea mays L.) variedad NB-S y rendimiento del chilote, a una densidad de 62,500 Plantas.ha-1. Se utilizó un diseño de bloques completos al azar (BCA) con cuatro repeticiones y los factores en estudio fueron los siguientes: Factor A (Laminas de riego por goteo) con 3 niveles: a1 (4.5Litros de agua/metro lineal.día), a2 (3.6 Litros de agua/metro lineal día) y a3 (2.5Litros de agua/metro lineal día). Factor B: Fraccionamiento de la dosis de nitrógeno de 100 kg. ha-1, con 3 niveles: b1 (100 % de la dosis aplicada a los 21 ddg); b2 dosis fraccionada (50 % de la dosis aplicada a los 21 ddg y 50 % de la dosis aplicada a los 42 ddg) y b3 dosis completa (100 % de la dosis aplicada a los 42ddg). Las variables de crecimiento evaluadas fueron: altura de planta (cm), diámetro del tallo (cm) y numero de hojas por planta; para las varia bles del rendimiento del chilote y sus principales componentes fueron: altura de la primera y segunda inserción del chilote (cm), diámetro del chilote con y sin bráctea (cm), longitud del chilote con y sin bráctea (cm), peso de 12 chilotes con y sin bráctea (kg), y rendimiento de chilote con bráctea (kg.ha-1). El análisis de varianza (ANDEVA) realizado a las mediciones de crecimiento dio significativo para los niveles del Factor A, Factor B y la interacción A x B a los 35 y 48 días después de la germinación. El ANDEVA realizado a las variables del rendimiento y sus principales componentes dio significativas para los niveles del Factor A, Factor B y la interacción A x B a los 60 días después de la germinación. De los nueve tratamientos evaluados, el tratamiento a1 b2 indujo al mayor rendimiento dechilote con una producción de 1,925.52 kg de chilote. ha-1, con un total de costos variables de 4,458.00C$. ha-1, un beneficio neto de 11,716.37 C$.ha-1 y una tasa de retorno marginal del 1,102.53 por ciento.
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Gadolinium oxide thin films have been prepared on silicon (100) substrates with a low-energy dual ion-beam epitaxial technique. Substrate temperature was an important factor to affect the crystal structures and textures in an ion energy range of 100-500 eV. The films had a monoclinic Gd2O3 structure with preferred orientation ((4) over bar 02) at low substrate temperatures. When the substrate temperature was increased, the orientation turned to (202), and finally, the cubic structure appeared at the substrate temperature of 700 degreesC, which disagreed with the previous report because of the ion energy. The AES studies found that Gadolinium oxide shared Gd2O3 structures, although there were a lot of oxygen deficiencies in the films, and the XPS results confirmed this. AFM was also used to investigate the surface images of the samples. Finally, the electrical properties were presented. (C) 2004 Elsevier B.V. All rights reserved.
Resumo:
The growth of InAsxSb1-x films on (100) GaSb substrates by liquid-phase epitaxy (LPE) has been investigated and epitaxial InAs0.3Sb0.7 films with InAs0.9Sb0.09 buffer layers have been successfully obtained. The low X-ray rocking curve FHWM values of InAs0.3Sb0.7 layer shows the high quality of crystal-orientation structure. Hall measurements show that the highest electron mobility in the samples obtained is 2.9 x 10(4) cm(2) V-1 s(-1) and the carrier density is 2.78 x 10(16)cm(-3) at room temperature (RT). The In As0.3Sb0.7 films grown on (10 0) GaSb substrates exhibit excellent optical performance with a cut-off wavelength of 12 mu m. (c) 2007 Elsevier B.V. All rights reserved.
Resumo:
Molecular dynamics (MD) simulations are performed to study the interaction of His-tagged peptide with three different metal surfaces in explicit water. The equilibrium properties are analyzed by using pair correlation functions (PCF) to give an insight into the behavior of the peptide adsorption to metal surfaces in water solvent. The intermolecular interactions between peptide residues and the metal surfaces are evaluated. By pulling the peptide away from the peptide in the presence of solvent water, peeling forces are obtained and reveal the binding strength of peptide adsorption on nickel, copper and gold. From the analysis of the dynamics properties of the peptide interaction with the metal surfaces, it is shown that the affinity of peptide to Ni surface is the strongest, while on Cu and An the affinity is a little weaker. In MD simulations including metals, the His-tagged region interacts with the substrate to an extent greater than the other regions. The work presented here reveals various interactions between His-tagged peptide and Ni/Cu/Au surfaces. The interesting affinities and dynamical properties of the peptide are also derived. The results give predictions for the structure of His-tagged peptide adsorbing on three different metal surfaces and show the different affinities between them, which assist the understanding of how peptides behave on metal surfaces and of how designers select amino sequences in molecule devices design. (c) 2007 Elsevier Ltd. All rights reserved.
Resumo:
本文讨论了利用赝势理论,按照Born稳定性判据,计算简单金属理论强度的方法。然后计算了六种简单金属(Li,Na,K,Rb,Cs和Pb)在0K和[100]单轴应力下的理论拉伸与压缩强度。
Resumo:
Constituintes da Comissão da Ordem Social propõem um sistema único de saúde de qualidade a todos os brasileiros. Todos os órgãos de saúde reunidos em um só sistema. Joaquim Lucena (PMDB-MT) esclarece que, com a nova proposta, todos terão direito iguais à saúde . Vicente Lobo (PMDB-RS) afirma que a unificação dos planos de saúde no país garantirá amparo as classes mais necessitadas. Proposta de descentralização do sistema público de saúde dará mais encargos para os estados e municípios. Borges da Silveira (PMDB-PR) relata sobre a descentralização na execução dos serviços de saúde onde cada estado estabelece seu programa de saúde. O Povo Pergunta, novo quadro do programa, permitirá ao cidadão fazer perguntas aos constituintes. Um cidadão pergunta sobre os mecanismos para controlar os gastos públicos. Valter Pereira (PMDB-MG) responde que a Comissão do Sistema Tributário, Orçamento e Finanças aprovou proposta que altera a estrutura, a composição e o funcionamento do Tribunal de Contas da União e dos Estados. Relata ainda que a sociedade estará representada nos tribunais e poderá controlar e fiscalizar os gastos públicos. Afonso Arinos (PFL-RJ), Presidente da Comissão de Sistematização, menciona o grande número de projetos e propostas apresentados. Afirma que os projetos são contraditórios e complexos e precisarão ser depurados pelo Plenário da Assembleia Nacional Constituinte (ANC).