990 resultados para Insertion de liens C-H


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BACKGROUND: Apolipoprotein (apo)B is the structural apoprotein of intestinally- and liver- derived lipoproteins and plays an important role in the transport of triacylglycerol (TAG) and cholesterol. Previous studies have examined the association between the APOB insertion/deletion (ins/del) polymorphism (rs17240441) and postprandial lipaemia in response to a single meal; however the findings have been inconsistent with studies often underpowered to detect genotype-lipaemia associations, focused mainly on men, or with limited postprandial characterisation of participants. In the present study, using a novel sequential test meal protocol which more closely mimics habitual eating patterns, we investigated the impact of APOB ins/del polymorphism on postprandial TAG, non-esterified fatty acids, glucose and insulin levels in healthy adults. FINDINGS: Healthy participants (n = 147) consumed a standard test breakfast (0 min; 49 g fat) and lunch (330 min; 29 g fat), with blood samples collected before (fasting) and on 11 subsequent occasions until 480 min after the test breakfast. The ins/ins homozygotes had higher fasting total cholesterol, LDL-cholesterol, TAG, insulin and HOMA-IR and lower HDL-cholesterol than del/del homozygotes (P < 0.017). A higher area under the time response curve (AUC) was evident for the postprandial TAG (P < 0.001) and insulin (P = 0.032) responses in the ins/ins homozygotes relative to the del/del homozygotes, where the genotype explained 35% and 7% of the variation in the TAG and insulin AUCs, respectively. CONCLUSIONS: In summary, our findings indicate that the APOB ins/del polymorphism is likely to be an important genetic determinant of the large inter-individual variability in the postprandial TAG and insulin responses to dietary fat intake.

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Layer-by-layer (LbL) films from K(2)Nb(6)O(17)(2-) and polyallylamine (PAH) and dip-coating films of H(2)K(2)Nb(6)O(17) were prepared on a fluorine-doped tin-oxide (FTO)-coated glass. The atomic force microscopy (AFM) images were carried out for morphological characterization of both materials. The real surface area and the roughness factor were determined on the basis of pseudocapacitive processes involved in the electroreduction/electrooxidation of gold layers deposited on these films. Next, lithium ion insertion into these materials was examined by means of electrochemical and spectroelectrochemical measurements. More specifically, cyclic voltammetry and current pulses under visible light beams were used to investigate mass transport and chromogenic properties. The lithium ion diffusion coefficient (D(Li)) within the LbL matrix is significantly higher than that within the dip-coating film, ensuring high storage capacity of lithium ions in the self-assembled electrode. Contrary to the LbL film, the potentiodynamic profile of absorbance change (Delta A) as a function of time is not similar to that obtained in the case of current density for the dip-coating film. Aiming at analyzing the rate of the coloration front associated with lithium ion diffusion, a spectroelectrochemical method based on the galvanostatic intermittent titration technique (GITT) was employed so as to determine the ""optical"" diffusion coefficient (D(op)). In the dip-coating film, the method employed here revealed that the lithium ion rate is higher in diffusion pathways formed from K(2)Nb(6)O(17)(2-) sites that contribute more significantly to Delta A. Meanwhile, the presence of PAH contributed to the increased ionic mobility in diffusion pathways in the LbL film, with low contribution to the electrochromic efficiency. These results aided a better understanding of the potentiodynamic profile of the temporal change of absorbance and current density during the insertion/deinsertion of lithium ions into the electrochromic materials.

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Pinacolyltellurium(IV) dihalides, (t-BuCOCH2)2TeX2 (X ) Br (1b), I (1c)) and Ar(t-BuCOCH2)TeCl2 (Ar == 1-C10H7 (Np) (2a), 2,4,6-Me3C6H2 (Mes) (3a)), are readily prepared at room temperature by the oxidative insertion of elemental tellurium into the Csp3-Br or -I bond of the α-halopinacolone and by the reaction of ArTeCl3 with the pinacolone t-BuCOCH3. The bromides Np(t-BuCOCH2)TeBr2 (2b) and Mes(t-BuCOCH2)TeBr2 (3b) can be prepared by the addition of bromine to the telluride Ar(t-BuCOCH2)-Te or of α-bromopinacolone to ArTeBr. Variable-temperature 1H and 13C NMR of the separate signals for the o-Me groups in 3a,b indicate a very high barrier to rotation about the Te-C(aryl) bond. Crystal diffraction data for 1c, 2a-c, and 3b show that intramolecular 1,4-Te …O(C) secondary bonding interactions (SBIs) are retained even in the presence of bulky aryl groups and intermolecular Te …X SBIs are subject to electronic population and steric congestion around the Te(IV) center in the solid state.

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Bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC6H4COCH2)2TeBr2, (y=H (1a), Me (1b), MeO (1c)) can be prepared
either by direct insertion of elemental Te across CRf-Br bonds (where CRf refers to α-carbon of a functionalized organic moiety) or by the oxidative addition of bromine to (p-YC6H4COCH2)2Te (y = H (2a), Me (2b), MeO (2c)). Bis(p-substituted benzoylmethyl)tellurium dichlorides, (p-YC6H4COCH2)2TeCh (y = H (3a), Me (3b), MeO (3c)), are prepared by the reaction of the bis(p-substituted benzoylmethyl)tellurides 2a--c with S02Cl2, whereas the corresponding diiodides (p-YC6H4COCH2)2Teh (y = H
(4a), Me (4b), MeO (4c)) can be obtained by the metathetical reaction of la--c with KI, or alternatively, by the oxidative addition of
iodine to 2a--c. The reaction of 2a--c with allyl bromide affords the diorganotellurium dibrornides la--c, rather than the expected
triorganotelluronium bromides. Compounds 1-4 were characterized by elemental analyses, IR spectroscopy, 1H, l3C and 125Te
NMR spectroscopy (solution and solid-state) and in case of Ie also by X-ray crystallography. (p-MeOC6H4COCH2)2TeBr2 (1c) provides, a rare example, among organotellurium compounds, of a supramolecular architecture, where C-H-O hydrogen bonds appear to be the non-covalent intermolecular associative force that dominates the crystal packing.

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Bacterial genomes reflect their adaptation strategies through nucleotide usage trends found in their chromosome composition. Bacteria, unlike eukaryotes contain a wide range of genomic G + C. This wide variability may be viewed as a response to environmental adaptation. Two overarching trends are observed across bacterial genomes, the first, correlates genomic G + C to environmental niches and lifestyle, while the other utilizees intra-genomic G + C incongruence to delineate horizontally transferred material. In this review, we focus on the influence of several properties including biochemical, genetic flows, selection biases, and the biochemical-energetic properties shaping genome composition. Outcomes indicate a trend toward high G + C and larger genomes in free-living organisms, as a result of more complex and varied environments (higher chance for horizontal gene transfer). Conversely, nutrient limiting and nutrient poor environments dictate smaller genomes of low GC in attempts to conserve replication expense. Varied processes including translesion repair mechanisms, phage insertion and cytosine degradation has been shown to introduce higher AT in genomic sequences. We conclude the review with an analysis of current bioinformatics tools seeking to elicit compositional variances and highlight the practical implications when using such techniques.

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When the small-pore zeolite natrolite is compressed at ca. 1.5 GPa and heated to ca. 110 &deg;C in the presence of CO2, the unit cell volume of natrolite expands by 6.8% and ca. 12 wt % of CO2 is contained in the expanded elliptical channels. This CO2 insertion into natrolite is found to be reversible upon pressure release.

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This paper presents a wide band RF MEMS capacitive switch. The LC resonant frequency is reduced from mm wave to X band frequencies at down-state by using a meander type membrane, with the frequency band is being increased by adding two short high impedance lines at both ends of coplanar waveguide (CPW). Moreover, this acts as T-match circuit in up-state position and improves the matching. Simulation results demonstrate that the capacitance ratio reduces from 50 to 21.4, S21 and S11 are less than −10dB for the entire frequency band at down-state and up-state. Also, a comprehensive and complete electric model of the switch is proposed and simulation results agree well with the characteristics of the physical structure of the MEMS switch. Vpull-in and Vpull-out of this switch are 8.1V and 0.3V, respectively.

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A presente pesquisa possui um enfoque no processo de internacionalização das empresas brasileiras, um fenômeno que vem ocorrendo de forma lenta e gradual ao longo dos últimos 25 anos, com grande ênfase nos anos 1990, quando o Brasil abriu sua economia ao capital externo, proporcionando maiores investimentos em novos produtos, novas tecnologias, e a adoção por parte das nossas organizações de novas formas e práticas de gestão empresarial, as quais já faziam parte há um bom tempo das organizações multinacionais pelo mundo afora, que sempre utilizaram essas melhores formas de gestão empresarial em seu estado da arte. Este atraso do Brasil em relação ao mundo desenvolvido, em que o País se fechou como uma verdadeira "ostra", refletiu-se em prejuízos imensuráveis ao desenvolvimento social, político e econômico, resultando em atrasos tecnológicos e educacionais e na consequente falta de pessoal qualificado em face de um mundo globalizado, no qual se mostram imprescindíveis as inovações tecnológicas e a capacitação humana. Nesse contexto, o processo de internacionalização de empresas, especificamente o segmento do cooperativismo de agronegócio no estado do Paraná, ganha um impulso significativo, quando as cooperativas, a partir da década de 1980, buscam sua inserção internacional no mundo globalizado através de um aumento gradativo em suas exportações, inicialmente somente com produtos in natura e, posteriormente, com a introdução de novas tecnologias, equipamentos, pesquisas, modernas formas de gestão e educação continuada de pessoal, possibilitando às cooperativas, e de forma geral ao setor cooperativista paranaense, um grande salto financeiro e um aumento expressivo na composição do PIB do Paraná, representando nos dias atuais aproximadamente 40% do total das exportações do estado. Dessa forma, este trabalho procura contribuir com a academia e com as organizações cooperativistas do estado do Paraná no sentido de buscar as razões para esse importante e irreversível processo de internacionalização, que trouxe, e ainda traz, vantagens financeiras, tecnológicas e dinamismo à economia local com os seus diversos atores, e que transforma essas organizações paranaenses e brasileiras em grandes players globais nos negócios internacionais.

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Le thème de cette dissertation est l Histoire de l éducation de la femme. Une analyse des pratiques culturelles de la professeur Anayde da Costa Beiriz (1905-1930), dans le contexte paraibanais du début du XXe siècle, est proposée. Le référentiel théoricométhodologique de l Histoire Culturelle est utilisé, pour aller contre l histoire passée sous silence dans le canon traditionnel. Basée sur le concept de représentation (Chartier, 1990), rompant avec les anciennes idées de sens intrinsèque, absolu, unique, liée aux pratiques complexes, multiples et différenciées, qui construisent le monde comme représentation. Basée aussi sur le concept de configuration (Elias, 1980), en comprenant que apparemment individu et société sont deux objets qui existent indépendamment, mais en vérité, se rapportent à deux niveaux inséparables du monde social, sont unis par des liens d interdépendance. Un dialogue est recherché entre le passé et le présent et les différentes dimensions: historique, sociale, politique et culturelle vécues par la professeur Anayde Beiriz. Pour obtenir des informations sur ses pratiques culturelles, une recherche des marques de cette histoire dans de multiples sources est effectuée: dans la bibliographie disponible parmi les domaines de la littérature, de l histoire, dês sciences sociales et de l éducation; dans des archives de l Institut Historique et Géographique de la Paraiba et de Natal; dans les Bibliothèques de l Université Fédérale de la Paraiba et du Rio Grande do Norte et chez des bouquinistes. L inventaire comprend: des périodiques, la législation en vigueur, des écrits de contemporains, dês témoignages oraux de parents, des lettres et des photos. On comprend de cette façon, que l idée d éplucher au travers de cette étude, des aspects qui n ont pas encore été vus et rappelés, peut non seulement répondre à nos doutes, mais, peut à partir de la réflexion qui se fait, se traduire par une nouvelle compréhension de cette histoire. En conclusion, des significations multiples sont contenues dans le processus d insertion de la femme dans l éducation à partir des Écoles Normales, qui englobent les relations de genre, l histoire du pouvoir, de la morale, de surpassement, des luttes et insatisfactions. On perçoit l héritage de résistances et de conquêtes. Cela a été sous l inspiration des airs de la modernité avec la Belle Époque, en répercutant dans le monde et aussi dans la Parahyba du Nord, que s est concrétisée la formation sociale de la professeur Anayde Beiriz et des femmes de son temps. L analyse de l écriture de soi confirme le discours normatif du contrôle moral social, le joug et les préjugés soufferts par Anayde Beiriz et l éducation différencié de genre qui ont déterminé ses habitudes et coutumes. C est-àdire, pour la femme, la permanence dans l espace privé, la retenue, l anoblissement des tâches ménagères et de la maternité comme sa plus haute aspiration, le support moral de la famille, la préservation de la tradition et la perpétuation des règles religieuses

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Purpose: This study evaluated the influence of distal extension removable partial denture associated with implant in cases of different bone level of abutment tooth, using 2D finite element analysis.Materials and Methods: Eight hemiarch models were simulated: model A-presenting tooth 33 and distal extension removable partial denture replacing others teeth, using distal rest connection and no bone lost; model B-similar to model A but presenting distal guide plate connection; model C-similar to model A but presenting osseointegrated implant with ERA retention system associated under prosthetic base; model D-similar to model B but presenting osseointegrated implant as described in model C; models E, F, G, and H were similar to models A, B, C, and D but presenting reduced periodontal support around tooth 33. Using ANSYS 9.0 software, the models were loaded vertically with 50 N on each cusp tip. For results, von Mises Stress Maps were plotted.Results: Maximum stress value was encountered in model G (201.023 MPa). Stress distribution was concentrated on implant and retention system. The implant/removable partial denture association decreases stress levels on alveolar mucosa for all models.Conclusions: Use of implant and ERA system decreased stress concentrations on supporting structures in all models. Use of distal guide plate decreased stress levels on abutment tooth and cortical and trabecular bone. Tooth apex of models with reduced periodontal support presented increased stress when using distal rest. (Implant Dent 2011;20:192-201)

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The aim of this study was to evaluate the presence of porosities inside the glass ionomer cement (GIC) after different techniques of material insertion. MATERIAL and METHOD: Specimens were prepared with high-viscosity GIC Ketac Molar Easymix and divided into three groups according to the insertion method: spatula (PI), Centrix injector (CI), and low-cost syringe (LCS). The specimens were fractured and observed with scanning electronic microscopy to quantitatively evaluate porosity inside the material using Image J Software. RESULTS: Statistical analysis, ANOVA application, and Tukey test to significance level of 5%, revealed that there was no statistical difference between the groups. CONCLUSION: Although the use of LCS has not decreased the porosity of the material, this insertion method is easy, accessible, and low cost, which makes it a viable alternative of use in the ART technique and in others bucal health programs. Microsc. Res. Tech., 2012. (c) 2012 Wiley Periodicals, Inc.

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Objectives: To evaluate the effect of insertion torque on micromotion to a lateral force in three different implant designs. Material and methods: Thirty-six implants with identical thread design, but different cutting groove design were divided in three groups: (1) non-fluted (no cutting groove, solid screw-form); (2) fluted (901 cut at the apex, tap design); and (3) Blossomt (Patent pending) (non-fluted with engineered trimmed thread design). The implants were screwed into polyurethane foam blocks and the insertion torque was recorded after each turn of 901 by a digital torque gauge. Controlled lateral loads of 10N followed by increments of 5 up to 100N were sequentially applied by a digital force gauge on a titanium abutment. Statistical comparison was performed with two-way mixed model ANOVA that evaluated implant design group, linear effects of turns and displacement loads, and their interaction. Results: While insertion torque increased as a function of number of turns for each design, the slope and final values increased (Po0.001) progressively from the Blossomt to the fluted to the non-fluted design (M +/- standard deviation [SD] = 64.1 +/- 26.8, 139.4 +/- 17.2, and 205.23 +/- 24.3 Ncm, respectively). While a linear relationship between horizontal displacement and lateral force was observed for each design, the slope and maximal displacement increased (Po0.001) progressively from the Blossomt to the fluted to the non-fluted design (M +/- SD 530 +/- 57.7, 585.9 +/- 82.4, and 782.33 +/- 269.4 mm, respectively). There was negligible to moderate levels of association between insertion torque and lateral displacement in the Blossomt, fluted and non-fluted design groups, respectively. Conclusion: Insertion torque was reduced in implant macrodesigns that incorporated cutting edges, and lesser insertion torque was generally associated with decreased micromovement. However, insertion torque and micromotion were unrelated within implant designs, particularly for those designs showing the least insertion torque.

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This in vitro study evaluated the marginal gap at the composite tooth/resin interface in class V cavities under the influence of two insertion techniques and a curing system by means of atomic force microscopy (AFM). Forty enamel and dentin cavities were prepared on the buccal surface in bovine teeth with quadratic forms measuring 2 mm X 2 mm and depth of 1.5 mm. The teeth were then divided into four groups: group A, 10 cavities were restored in one increment, light cured by halogen light; group B, 10 cavities filled with bulk filling, light cured by the light emitting diodes (LED); group C, 10 cavities were restored by the incremental technique, light cured by halogen light; group D, 10 cavities were restored by the incremental technique, light cured by the LED. The teeth underwent the polishing procedure and were analyzed by AFM for tooth/restoration interface evaluation. The data were compared between groups using the nonparametric Kruskall-Wallis and Mann-Whitney tests (p < 0.05). The results showed a statistically significant difference between groups A and B and groups A and C. It was concluded that no insertion and polymerization technique was able to completely seal the cavity.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The dynamics of the restricted three-body Earth-Moon-particle problem predicts the existence of direct periodic orbits around the Lagrangian equilibrium point L1. From these orbits, we derive a set of trajectories that form links between the Earth and the Moon and are capable of performing transfers between terrestrial and lunar orbits, in addition to defining an escape route from the Earth-Moon system. When we consider a more complex and realistic dynamical system - the four-body Sun-Earth-Moon-particle (probe) problem - the trajectories have an expressive gain of inclination when they penetrate in the lunar influence sphere, thus allowing the insertion of probes into low-altitude lunar orbits with high inclinations, including polar orbits. In this study, we present these links and investigate some possibilities for performing an Earth-Moon transfer based on these trajectories. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.