991 resultados para III V material
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Inscripción en la parte inf.: " 84"
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Trägerband: Inc. qu. 1200 ; Vorbesitzer: Karmeliterkloster Frankfurt am Main
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Trägerband: 'Aus: Crescentius. Louvain 1474'
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Trägerband: Inc. qu. 1272; Vorbesitzer: Dominikanerkloster Frankfurt am Main
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A Jacobsen-type catalyst was anchored onto an amine functionalised hexagonal mesoporous silica (HMS) through the diimine bridge fragment of the complex. The new heterogeneous catalyst, as well as the precedent materials, were characterised by elemental analyses, FTIR-DRIFT, UV-vis, porosimetry and XPS which showed that the complex was successfully anchored. This material was active in the epoxidation of styrene and α-methylstyrene in dichloromethane at 0°C using, respectively, m-CPBA/NMO and NaOCl. With the former substrate no asymmetric induction was found in the epoxide, whereas with the latter substrate higher %ee was found than in homogeneous phase. Using the latter experimental conditions, catalyst reuse led to no significant loss of catalytic activity and enantioselectivity. © 2005 Elsevier B.V. All rights reserved.
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Trägerband: Inc. oct. 473; 'Homil. cath. 686a'; Vorbesitzer: Dominikanerkloster Frankfurt am Main
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En el 2003, cuando se conformó el equipo de investigación que ahora constituye la línea de Teoría de Derecho del Grupo de Investigaciones Jurídicas de la Universidad de Medellín, se planteó como una necesidad la socialización de los resultados de investigación que fuesen obtenidos, por medio de eventos internacionales organizados por línea. Fue así como en ese año se propuso la primera versión de un seminario internacional e investigativo, cuyo eje central fueron los principios generales del derecho. El objetivo de dicho evento fue el darle al estudiante y el egresado de Derecho, los elementos básicos para una visión global y una mejor comprensión de los principios generales de Derecho, piedra angular en la formación jurídica, Así, el 24 de octubre se realizó la primera versión de este nuevo evento, contando con la participación de destacados profesores nacionales e internacionales. Esta obra reúne las ponencias de este evento, las cuales se constituyen en material valioso para los lectores interesados por el tema.
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Although various abutment connections and materials have recently been introduced, insufficient data exist regarding the effect of stress distribution on their mechanical performance. The purpose of this study was to investigate the effect of different abutment materials and platform connections on stress distribution in single anterior implant-supported restorations with the finite element method. Nine experimental groups were modeled from the combination of 3 platform connections (external hexagon, internal hexagon, and Morse tapered) and 3 abutment materials (titanium, zirconia, and hybrid) as follows: external hexagon-titanium, external hexagon-zirconia, external hexagon-hybrid, internal hexagon-titanium, internal hexagon-zirconia, internal hexagon-hybrid, Morse tapered-titanium, Morse tapered-zirconia, and Morse tapered-hybrid. Finite element models consisted of a 4×13-mm implant, anatomic abutment, and lithium disilicate central incisor crown cemented over the abutment. The 49 N occlusal loading was applied in 6 steps to simulate the incisal guidance. Equivalent von Mises stress (σvM) was used for both the qualitative and quantitative evaluation of the implant and abutment in all the groups and the maximum (σmax) and minimum (σmin) principal stresses for the numerical comparison of the zirconia parts. The highest abutment σvM occurred in the Morse-tapered groups and the lowest in the external hexagon-hybrid, internal hexagon-titanium, and internal hexagon-hybrid groups. The σmax and σmin values were lower in the hybrid groups than in the zirconia groups. The stress distribution concentrated in the abutment-implant interface in all the groups, regardless of the platform connection or abutment material. The platform connection influenced the stress on abutments more than the abutment material. The stress values for implants were similar among different platform connections, but greater stress concentrations were observed in internal connections.
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The present paper describes the synthesis of molecularly imprinted polymer - poly(methacrylic acid)/silica and reports its performance feasibility with desired adsorption capacity and selectivity for cholesterol extraction. Two imprinted hybrid materials were synthesized at different methacrylic acid (MAA)/tetraethoxysilane (TEOS) molar ratios (6:1 and 1:5) and characterized by FT-IR, TGA, SEM and textural data. Cholesterol adsorption on hybrid materials took place preferably in apolar solvent medium, especially in chloroform. From the kinetic data, the equilibrium time was reached quickly, being 12 and 20 min for the polymers synthesized at MAA/TEOS molar ratio of 6:1 and 1:5, respectively. The pseudo-second-order model provided the best fit for cholesterol adsorption on polymers, confirming the chemical nature of the adsorption process, while the dual-site Langmuir-Freundlich equation presented the best fit to the experimental data, suggesting the existence of two kinds of adsorption sites on both polymers. The maximum adsorption capacities obtained for the polymers synthesized at MAA/TEOS molar ratios of 6:1 and 1:5 were found to be 214.8 and 166.4 mg g(-1), respectively. The results from isotherm data also indicated higher adsorption capacity for both imprinted polymers regarding to corresponding non-imprinted polymers. Nevertheless, taking into account the retention parameters and selectivity of cholesterol in the presence of structurally analogue compounds (5-α-cholestane and 7-dehydrocholesterol), it was observed that the polymer synthesized at the MAA/TEOS molar ratio of 6:1 was much more selective for cholesterol than the one prepared at the ratio of 1:5, thus suggesting that selective binding sites ascribed to the carboxyl group from MAA play a central role in the imprinting effect created on MIP.
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Surgical treatment for enterocutaneous fistulas (EF) frequently fails. Cell therapy may represent a new approach to treatment. Mesenchymal stromal cells (MSCs) have high proliferative and differentiation capacity. This study aimed to investigate whether MSCs could adhere to suture filament (SF), promoting better EF healing. MSCs, 1 × 10(6), from adipose tissue (ATMSCs) were adhered to a Polyvicryl SF by adding a specific fibrin glue formulation. Adhesion was confirmed by confocal and scanning electron microscopy (SEM). A cecal fistula was created in 22 Wistar rats by incising the cecum and suturing the opening to the surgical wound subcutaneously with four separate stitches. The animals were randomly allocated to three groups: control (CG)-five animals, EF performed; injection (IG)-eight animals 1 × 10(6) ATMSCs injected around EF borders; and suture filament (SG): nine animals, sutured with 1 × 10(6) ATMSCs attached to the filaments with fibrin glue. Fistulas were photographed on the operation day and every 3 days until the 21st day and analyzed by two observers using ImageJ Software. Confocal and SEM results demonstrated ATMSCs adhered to SF (ATMSCs-SF). The average reduction size of the fistula area at 21st day was greater for the SG group (90.34%, P < 0.05) than the IG (71.80%) and CG (46.54%) groups. ATMSCs adhered to SF maintain viability and proliferative capacity. EF submitted to ATMSCs-SF procedure showed greater recovery and healing. This approach might be a new and effective tool for EF treatment.
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Jute fiber is the second most common natural cellulose fiber worldwide, especially in recent years, due to its excellent physical, chemical and structural properties. The objective of this paper was to investigate: the thermal degradation of in natura jute fiber, and the production and characterization of the generated activated carbon. The production consisted of carbonization of the jute fiber and activation with steam. During the activation step the amorphous carbon produced in the initial carbonization step reacted with oxidizing gas, forming new pores and opening closed pores, which enhanced the adsorptive capacity of the activated carbon. N2 gas adsorption at 77K was used in order to evaluate the effect of the carbonization and activation steps. The results of the adsorption indicate the possibility of producing a porous material with a combination of microporous and mesoporous structure, depending on the parameters used in the processes, with resulting specific surface area around 470 m2.g-1. The thermal analysis indicates that above 600°C there is no significant mass loss.
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The objective of the study was to illustrate the applicability and significance of the novel Lewis urothelial cancer model compared to the classic Fisher 344. Fischer 344 and Lewis females rats, 7 weeks old, were intravesical instilled N-methyl-N-nitrosourea 1.5 mg/kg every other week for a total of four doses. After 15 weeks, animals were sacrificed and bladders analyzed: histopathology (tumor grade and stage), immunohistochemistry (apoptotic and proliferative indices) and blotting (Toll-like receptor 2-TLR2, Uroplakin III-UP III and C-Myc). Control groups received placebo. There were macroscopic neoplastic lesions in 20 % of Lewis strain and 70 % of Fischer 344 strain. Lewis showed hyperplasia in 50 % of animals, normal bladders in 50 %. All Fischer 344 had lesions, 20 % papillary hyperplasia, 30 % dysplasia, 40 % neoplasia and 10 % squamous metaplasia. Proliferative and apoptotic indices were significantly lower in the Lewis strain (p < 0.01). The TLR2 and UP III protein levels were significantly higher in Lewis compared to Fischer 344 strain (70.8 and 46.5 % vs. 49.5 and 16.9 %, respectively). In contrast, C-Myc protein levels were significantly higher in Fischer 344 (22.5 %) compared to Lewis strain (13.7 %). The innovative Lewis carcinogen resistance urothelial model represents a new strategy for translational research. Preservation of TLR2 and UP III defense mechanisms might drive diverse urothelial phenotypes during carcinogenesis in differently susceptible individuals.
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We estimate litter production and leaf decomposition rate in a cerradão area, physiognomy little studied and very threatened in São Paulo State. During the period of study, litter production was 5646.9 kg.ha-1.year-1, which the 'leaf' fraction corresponded to 4081.2 kg.ha¹.year¹; the 'branch' fraction, to 1066.1 kg.ha-1.year-1; the 'reproductive structures' fraction, to 434.1 kg.ha-1.year-1; and the 'miscellaneous' fraction to 65.5 kg.ha-1.year-1. Litter production was highly seasonal and negatively correlated with relative humidity and air temperature. Leaf production was negatively correlated with relative humidity, rainfall, and air temperature. There was no significant difference between litter production found in this study and those in two other sites with cerradão and semideciduous forest, but these physiognomies differed significantly from the cerrado sensu stricto. Leaf decomposition rate (K) was 0.56. Half-life of the decomposing material was 1.8 years and turnover time was 2.3 years.
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A case of neuronal ceroid-lipofuscinosis (NCL) is reported in a 11-year-old girl, whose main symptoms were progressive dementia since the age of 4 years and choreic movements since age 10. Seizures, myoclonus and visual deterioration were absent and optic fundi were normal. A cerebral biopsy disclosed two basic types of stored substance in the cytoplasm of neurons: a) severely balloned nerve cells in cortical layers HI and V contained a non-autofluorescent material, which stained with PAS and Sudan Black B in frozen, but not in paraffin sections; ultrastructurally, these neurons showed abundant corpuscles similar to the membranous cytoplasmic bodies of Tay-Sachs disease and, in smaller amounts, also zebra bodies; b) slightly distended or non-distended neurons in all layers contained lipopigment granules, which were autofluorescent, PAS-positive and sudanophil in both frozen and paraffin sections; their ultrastructure was closely comparable to that of lipofuscin. Similar bodies were found in the swollen segments of axons and in a few astrocytes and endothelial cells. The histochemical and ultrastructural demonstration of large amounts of lipopigments allows a presumptive classification of the case as NCL. However, the presence of involuntary movements, the absence of visual disturbances and the unusual ultrastructural features place the patient into a small heterogeneous group within the NCL. A better classification of such unique instances of the disease must await elucidation of the basic enzymatic defects.