267 resultados para Polarization microscopy
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This study aimed to evaluate and correlate intraocular pressure (IOP), endothelial cell density (CD), and hexagonality (HEX), and the aqueous humor prostaglandin E-2 (PGE(2)) concentration in dogs with mature (MG, n = 8) and hypermature (HG, n = 8) cataracts. Eight laboratory beagles with no ocular abnormalities were included as a control group (CG). The IOP was measured using a digital applanation tonometer. Noncontact specular microscopy was used to evaluate CD and HEX. Samples of aqueous humor were used to determine prostaglandin E-2 concentration using enzyme-linked immunoassay. Data were compared by ANOVA and Bonferroni's multiple comparison test, and possible correlations among the PGE(2) aqueous concentration and corneal endothelium cell parameters were assessed by Person's test (P < 0.05). Average values of IOP (P = 0.45) and CD (P = 0.39) were not significantly different between MG, HM, and CG. Average values of HEX were lower, and PGE(2) concentration was increased in the MG and HG in comparison with CG (P < 0.05); however, such parameters did not change significantly between MG and HG (P > 0.05). PGE(2) values did not correlate with IOP, CD, and HEX in any group (P > 0.05). Although there were a small number of dogs studied, our results demonstrated that cataract progression from mature to hypermature did not have a significant change in PGE(2) aqueous concentration, IOP, corneal endothelial cell count, or morphology. In addition, PGE(2) concentration was not correlated with parameters of the corneal endothelium or IOP in dogs with mature or hypermature cataracts.
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Monitoring non-ionizing radiant energy is increasingly demanded for many applications such as automobile, biomedical and security system. Thermal type infrared (IR) sensors can operate at room temperature and pyroelectric materials have high sensitivity and accuracy for that application. Working as thermal transducer pyroelectric sensor converts the non-quantified thermal flux into the output measurable quantity of electrical charge, voltage or current. In the present study the composite made of poly(vinylidene fluoride) -PVDF and lead zirconate titanate (PZT) partially recovered with polyaniline (PAni) conductor polymer has been used as sensor element. The pyroelectric coefficient p(T) was obtained by measuring the pyroelectric reversible current, i.e., measuring the thermally stimulated depolarization current (TSDC) after removing all irreversible contribution to the current such as injected charge during polarization of the sample. To analyze the sensing property of the pyroelectric material, the sensor is irradiated by a high power light source (halogen lamp of 250 W) that is chopped providing a modulated radiation. A device assembled in the laboratory is used to change the light intensity sensor, an aluminum strip having openings with diameters ranging from 1 to 10 mm incremented by one millimeter. The sensor element is assembled between two electrodes while its frontal surface is painted black ink to maximize the light absorption. The signal from the sensor is measured by a Lock-In amplifier model SR530 -Stanford Research Systems. The behavior of the output voltage for an input power at several frequencies for PZT-PAni/PVDF (30/ 70 vol%) composite follows the inverse power law (1/ f) and the linearity can be observed in the frequency range used.
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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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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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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Química - IQ
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)