502 resultados para Ondas de densidade de carga

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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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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Neste estudo, foram investigadas as densidades de carga adequadas para transporte de matrinxãs juvenis em sistema fechado com sacos plásticos. O transporte de 4h foi feito com peixes (23,5±0,4g; 11,6 (0,08cm) em jejum por 24h, em densidades de 83g L-1 (D1), 125g L-1 (D2), 168g L-1 (D3) e 206g L-1 (D4). Os peixes foram amostrados antes do transporte (AT), logo após o transporte (chegada) (DT) e 24h depois. A qualidade da água foi monitorada antes da captura dos peixes nos tanques de depuração, após o transporte nos sacos plásticos e nos tanques de recuperação. O oxigênio da água diminuiu para valores inferiores a 4mg L-1 em D2, D3 e D4, a temperatura esteve em torno de 32°C, pH 6,5-6,78, a amônia total foi de 1,09-1,7mg L-1, a amônia não-ionizada foi de 3,58-9,33 x 10³mg L-1 e alcalinidade 134-165mg CaCO3 L-1. O cortisol plasmático e a glicose sanguínea aumentaram após o transporte nos peixes em todas as densidades ensaiadas, voltando aos valores controle 24h depois. Os valores de osmolaridade não mudaram logo após o transporte, mas aumentaram 24h depois de modo igual em todas as densidades. O cloreto plasmático diminuiu na chegada, de modo inversamente proporcional à densidade de carga. O hematócrito diminuiu 24h depois da chegada dos peixes, em todas as densidades testadas, mas não houve diferença no número de eritrócitos. Não houve mortalidade até uma semana após o transporte. O matrinxã mostrou ser uma espécie tolerante a altas densidades de carga em embalagens para transporte além de suportar baixos níveis de oxigênio na água.

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Pós-graduação em Biofísica Molecular - IBILCE

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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The pH values near a planar dissociating membrane are studied under a mean field approximation using the Poisson-Boltzmann equation and its linear form. The equations are solved in planar symmetry with the consideration that the charge density on the dissociating membrane surface results from an equilibrium process with the neighboring electrolyte. Results for the membrane dissociation degree are presented as a function of the electrolyte ionic strength and membrane surface charge density. Our calculations indicate that pH values have an appreciable variation within 2 nm from the membrane. It is shown that the dissociation process is enhanced due to the presence of bivalent ions and that pH values acquire better stability than in an electrolyte containing univalent ions.

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Chitosan is a natural biodegradable polymer with great potential for pharmaceutical applications due to its biocompatibility, high charge density , nontoxicity and mucoadhesion. Gel formation can be obtained by the interactions of chitosans with low molecular counterions such as polyphosphates, sulphates and crosslinking with glutaraldehyde. This gelling property of chitosan allows a wide range of applications such as coating of pharmaceuticals and food products, gel entrapment of biochemicals, whole cells, microorganisms and algae. One of its main applications is the synthesis of microspheres for coating of pharmaceuticals , magnetic particles an other substances. In such a way, we can build targeted drug delivery systems. In the present work, we applied the method of spraying and coagulation. The resulting microspheres, then, were characterized by optical microscopy

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The porpoise of this study was to evaluate the effects of extracorporeal shock waves in third metacarpus bone from healthy horses by determination of bone elasticity. It were used 20 Thoroughbred horses, male and female, with two years old, on top of training and selected as the state healthy. At the beginning of the experiment (D0), all animals were submitted for evaluation of bone elasticity held in the third metacarpus bone. The animals were divided into two groups (Control Group - CG and Experimental Group - EG). The application of extracorporeal shock wave therapy (ESWT) was performed on the right forelimb of the animals in the experimental group in the same place evaluated for bone elasticity and was used apparatus for extracorporeal therapy of waves with 0.15 mJ/mm2 energy flux density and 2000 pulses with E6R20 probe, with focus feature of the shock wave of 20 mm. The ESWT were repeated every 21 days, a total of three sessions (D0, D21 and D42). The analysis of bone elasticity determination was realized at D21, D42 and D72. The average of speed ultrasound differed between groups at D21, D42 and D72, and the animals from EG had lower bone mineral density after applications of ESWT. There was also difference in the analysis of bone mass (Z-Score) between the groups at D21 and D42, which animals from EG showed a significant decrease in bone mass. The risk of fracture was higher in animals from experimental group at D21. It was concluded that ESWT is able to promote change in bone mineral density.

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The suspension of rats by the tail model is used to investigate the behavior of bone in animals unable to move around. Bone is an adaptative tissue that develops in structure and function, among other factors, in response to mechanical forces applied to it and metabolic demands that it will suffer. The absence of mechanical forces and deformation of bone that occurs causes a decrease in calcium deposition in the absence of stimuli on osteoblasts and osteocytes, favoring the action of osteoclasts, making bones weak and brittle. Therefore, the mechanical action is necessary to stimulate local bone response and thus provide growth and remodeling. The aim of this study was to evaluable by radiographic densitometry, the tail suspension for 15 and 36 days alter the bone mineral density of cervical vertebrae (C3), thoracic (T6) and lumbar (L1 and L3) of Wistar rats. Thirty Rattus norvegicus albinus, adult, male, Wistar strain, average body mass ± 350g, were divided into 3 groups: control (n = 10) - not suspended; S15 (n = 10) - suspended for 15 days and S36 (n = 10) - suspended for 36 days. For densitometric analysis vertebrae were radiographed, scanned, digitized and analyzed by the computer program ImageJ®. There was a statistically significant increase in bone mineral density in group S15, probably by the restlessness of the animals to the suspension, with a decrease in group S36, and this hypothetically is linked to the accommodation of the rats, concluding that the tail suspension altered bone mineral density in first time with a decrease over time.

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

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No-till has been used in many different regions of Brazil. However, depending on the location and intensity of machinery traffic, this has caused the problem of soil compaction and many producers are scarification the land as a solution to break through the layer that is restricting plant growth. The objective of this study was to evaluate the influence of scarification (0.30 m) in the physical properties of a dystrophic Alfisol comparing the results with a non-scarified contiguous area; both were previously conducted using no-till. The density and pressure of pre-consolidation were sampled in two areas of non-tillage, one with chiseling (PDCE) and one without (PDSE) by using the UMAS -Mobile Soil Sampling Unit built by NEMPA – Agroforestry Machinery and Tire Testing Center/FCA / UNESP, Botucatu ,SP. The UMAS is equipped with GPS which allows the samples to be georeferenced. The samples were evaluated in the laboratory through the collection of standardized rings. Sampling was performed at a dimension of 15 x 50 m, with 160 rings being collected. The samples containing rings which were used in determining the density and also for testing the consolidometer, were collected from the layers of 0 to 0.10 m, 0.10 to 0.20 m, 0.20 to 0.30 0.30 to I 0.40 m. For the odometer test the undisturbed sample rings were used in obtaining the load bearing capacity of the soil. The soil management adopted provided a decrease in soil density using no-tillage with scarification depths from 0.0 to 0.10 0.10 to 0.20 m while the other depths did not show any decrease. The pre-consolidation pressure in combination with soil aggregate resistance identified that the management process PDCE within all layers was subjected to water content reliability regarding a greater load bearing capacity of the soil. For the PDSE that only was possible in the 0 to 0.10 m, showing greater consolidation of this layer.

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Há evidências de que o ultrassom (US) de baixa intensidade pode acelerar a regeneração óssea. Este trabalho objetivou verificar a ação do US no defeito ósseo, criado experimentalmente em tíbias de ratos sob ausência de carga. Vinte Rattus novergicus albinus, Wistar adultos, divididos em: G1 (n=10), grupo experimental de 15 dias sem suspensão, e G2 (n=10), grupo experimental de 15 dias suspenso pela cauda, foram submetidos à osteotomia em ambas as tíbias e à aplicação do US, frequência de 1,5 MHz, ciclo de trabalho 1:4, 30 mW/cm², nas tíbias direitas por 12 sessões de 20 minutos. Após o sacrifício, as tíbias foram submetidas à análise da Densidade Mineral Óssea (DMO). Os resultados demonstraram DMO de 0,139±0,018 g/cm² para tíbia tratada; 0,131±0,009 g/cm² para tíbia controle no G1; e no G2 registrou-se 0,120±0,009 g/cm² para tíbia tratada e 0,106±0,017 g/cm² para tíbia controle. Houve diferença significante entre os grupos nos quais o G2 apresentou menor DMO, o que demonstra que a suspensão prejudica a manutenção das propriedades ósseas, e entre as tíbias tratadas e controles do G2, demonstrando que o US acelerou o processo de reparo, concluindo que a impossibilidade do estímulo mecânico causada pela não deambulação em um processo de reparo ósseo pode ser minimizada pela ação do US. No G1, a aplicação do US não teve influência significante no aumento da DMO, talvez pelo fato dos animais já terem estímulo mecânico suficiente à formação óssea.