130 resultados para initial chamber
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The effects of different feeding schemes on pacu Piaractus mesopotamicus early development were evaluated with respect to growth, survival, muscle development, and differential gene expression of MyoD and myogenin. The pacu larvae (4 days post hatch-dph, 0.77 mg wet weight) were given six feeding treatments intentionally designed to cause variations in the larvae growth rate: (A) only artemia nauplii; (CD) only a commercial diet; (ED) only a semi-purified experimental diet; (ACD) and (AED) two treatments that involved weaning; and (S) starvation. Early weaning from artemia nauplii to the formulated diets (ACD and AED) affected growth and survival of the pacu larvae compared with the exclusive use of artemia (A). Starvation (S) and the commercial diet (CD) caused total mortality in pacu larvae at 18 dph. The experimental diet (ED) assured low fish survival and growth. The skeletal muscle morphology was not affected by the delay in somatic growth from early weaning onto the formulated diets. Three distinct muscle compartments were observed throughout the larval development in treatments A, ACD and AED: superficial, deep and intermediate, accompanied by muscle thickening. Severe undernourishment caused drastic differences in growth and in the morphology of the muscle fibers. Pacu larvae fed only formulated diets (CD and ED) showed muscle characteristics similar to the larvae in starvation (S) during the first 15 dph. At 27 and 35 dph, a slight increase in epaxial muscle mass was noted in larvae fed only the experimental diet (ED). At 35 dph, we observed a high frequency of fibers >= 40 mu m in the larvae that were weaned onto the formulated diets (ACD and AED), indicative of hypertrophy. In contrast, the larvae fed only artemia nauplii (A) displayed a larger number of fibers with diameters <= 20 mu m, which is indicative of hyperplasia. The expression of the MyoD and myogenin genes in pacu larvae at 35 dph was not affected by initial feeding (p>0.05). In conclusion, the formulated diets used impaired pacu larvae growth and survival; therefore, they were inadequate for pacu, at least at the times they were introduced. Artemia nauplii were the most adequate food source during first feeding of the pacu, and they produced bigger fish upon completion of the experiment. Moreover, the contribution of hyperplasia to the skeletal muscle growth appeared higher in fast- than in slow-growing pacu larvae. (C) 2011 Elsevier By. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The anatomy and ultrastructure of root nodules of Anadenanthera peregrina var. falcata (Leguminosae-Mimosoideae) were analysed, as was plant growth. To ensure that nodules developed, seedlings were inoculated with a mixture of six strains of rhizobia. Nodules were produced that differed in appearance-and probably also effectiveness-but their structure was similar and they showed characteristics typical of indeterminate nodules, such as persistent meristematic tissue and a gradient of cells at different stages of development. Many starch grains were present in inner cortex cells and interstitial cells of infected tissue. Infected cells were densely packed with bacteroids, which contained many poly-beta-hydroxybutyrate granules. The high incidence of these granules, together with high levels of starch accumulation in interstitial cells, suggested low N-2-fixation efficiency of the rhizobia isolates used for inoculation. In the symbiosomes of early-senescent infected cells, reticulum-like structures, small vesicles and a fibrillar material were observed; these may be related to bacteroid degradation. In the cytoplasm of late-senescent infected cells, many vesicles and membrane-like structures were observed, probably associated with membrane degradation of bacteroids and peribacteroids. The total biomass of plants inoculated with rhizobia was low and their xylopodia and shoots had low levels of N compared with non-inoculated plants fertilized with ammonium nitrate. However, inoculated plants did not show N-deficiency symptoms and grew better than non-inoculated plants without N fertilization. These growth results, together with ultrastructural observations of nodules, suggest that nitrogen fixation of rhizobia isolates associated with Anadenanthera peregrina var. falcata roots is poor. (C) 2002 Annals of Botany Company.
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Convulxin, an alphabeta C-type lectin, is a potent platelet activator isolated from the venom of the South American rattlesnake Crotalus durissus terrificus. It is a 26.5 kDa alphabeta heterodimer consisting of two homologous disulfide-linked chains. The crystals belong to space group I4, with unit-cell parameters a = b = 131.61, c = 121.85 Angstrom, and diffraction data were collected to 2.7 Angstrom. The structure was solved by molecular replacement and the asymmetric unit contains two alphabeta heterodimers, each of which forms a disulfide-linked cyclic alpha(4)beta(4) tetramer in the unit cell. These alpha(4)beta(4) tetramers are stacked to form a large solvent channel.
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Purpose: To quantify the amount of peroxide penetration from the pulp chamber to the external surface of teeth during the walking bleaching technique. Methods: Seventy-two bovine lateral incisors were randomly divided over five experimental groups and one control (n = 12 per group): (1) 35% hydrogen peroxide (HP); (2) 35% carbamide peroxide (CP); (3) sodium perborate (SP); (4) (HP+SP); (5) (CP+SP) and (6) Control (CG), deionized water. All groups were treated according to the walking bleach technique. After 7 days at 37 degrees C in an acetate buffer solution, 100 mu l violet leukocrystal coloring and 50 mu l peroxidase was added, producing a blue stain that could be measured in a spectrophotometer and then converted into peroxide mu g/ml. Results: G5 exhibited the greatest penetration, while G2 and G3 produced the lowest values. All bleaching agents penetrated from the pulp chamber to the external root surface. There was a direct correlation between the presence of oxidative agents and penetration potential. Sodium perborate in distilled water was less oxidative and appeared to be the least aggressive bleaching agent. (Am J Dent 2010;23:171-174).
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Statement of the Problem: The effectiveness of low-intensity red laser for activating a bleaching gel and its effect in pulp temperature was not investigated in dental literature. Purpose: The objective of this study was to assess the effectiveness of low-intensity red laser for activating a bleaching gel, as well as its effect in temperature of the bleaching gel and the dental pulp. Materials and Methods: Forty extracted bovine teeth were immersed in a solution of coffee 14 days for darkening. The initial colors were recorded by spectrophotometric analysis. The specimens were randomly distributed into two groups (N = 20): the control, which did not receive light and the experimental group that received light from an appliance fitted with three red light-emitting laser diodes (? = 660 nm). A green-colored, 35% H2O2based bleaching gel was applied for 30 minutes, and changed three times. After bleaching, the colors were again measured to obtain the L*a*b* values. Color variation was calculated (?E) and the data submitted to the non-paired t-test (5%). To assess temperature, 10 human incisors were prepared, in which one thermocouple was placed on the bleaching gel applied on the surface of the teeth and another inside the pulp chamber. Results: There was a significant difference between the groups (p = 0.016), and the experimental group presented a significantly higher mean variation (7.21 +/- 2.76) in comparison with the control group (5.37 +/- 1.76). There was an increase in pulp temperature, but it was not sufficient to cause damage to the pulp. Conclusion: Bleaching gel activation with low-intensity red laser was capable of increasing the effectiveness of bleaching treatment and did not increase pulp temperature to levels deleterious to the pulp. CLINICAL SIGNIFICANCE The application of a low-intensity red laser was effective for activating a bleaching gel with green dye, without any deleterious increases in pulpal temperature. (J Esthet Restor Dent 24:126134, 2012)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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OBJETIVO: a ancoragem óssea é fundamental para o sucesso do tratamento de algumas más oclusões, pois permite a aplicação de forças contínuas, diminui o tempo de tratamento e independe da colaboração do paciente. MÉTODOS: o propósito desse trabalho foi comparar, por meio de modelos dentários, a perda de ancoragem após a retração inicial de caninos superiores entre dois grupos. O grupo A utilizou o mini-implante enquanto o grupo B utilizou o Botão de Nance. Para todos os pacientes foram realizados dois modelos (M1 e M2). Os primeiros modelos foram realizados ao início (M1), e os outros ao final da retração inicial de canino (M2). RESULTADOS: todas as medidas foram tabuladas e submetidas à análise estatística. Para verificar o erro sistemático intraexaminador foi utilizado o teste t pareado. Na determinação do erro casual utilizou-se o cálculo de erro proposto por Dahlberg. Para comparação entre as fases Início e Após, foi utilizado o teste t pareado. Para a comparação entre os grupos de mini-implante e Botão de Nance, foi utilizado o teste t de Student para medidas independentes. em todos os testes foi adotado nível de significância de 5% (p<0,05). CONCLUSÃO: ao se medir e comparar em modelos dentários a perda de ancoragem dos molares após a retração inicial de canino utilizando-se dois sistemas de ancoragem distintos (Mini-implante e Botão de Nance), pôde-se observar a inexistência de diferença estatisticamente significativa entre os dois grupos.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A new class of accelerating, exact, explicit and simple solutions of relativistic hydrodynamics is presented. Since these new solutions yield a finite rapidity distribution, they lead to an advanced estimate of the initial energy density and life-time of high energy heavy ion collisions. Accelerating solutions are also given for spherical expansions in arbitrary number of spatial dimensions.