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- ItemSomente MetadadadosBiocompatible silver nanoparticles prepared with amino acids and a green method(Springer Wien, 2017) de Matos, Ricardo Almeida [UNIFESP]; Courrol, Lilia Coronato [UNIFESP]The synthesis of nanoparticles is usually carried out by chemical reduction, which is effective but uses many toxic substances, making the process potentially harmful to the environment. Hence, as part of the search for environmentally friendly or green synthetic methods, this study aimed to produce silver nanoparticles (AgNPs) using only AgNO3, Milli-Q water, white light from a xenon lamp (Xe) and amino acids. Nanoparticles were synthetized using 21 amino acids, and the shapes and sizes of the resultant nanoparticles were evaluated. The products were characterized by UV-Vis, zeta potential measurements and transmission electron microscopy. The synthesis of silver nanoparticles with tryptophan and tyrosine, methionine, cystine and histidine was possible through photoreduction method. Spherical nanoparticles were produced, with sizes ranging from 15 to 30 nm. Tryptophan does not require illumination nor heating, and the solution color changes immediately after the mixing of reagents if sodium hydroxide is added to the solution (pH = 10). The Xe illumination acts as sodium hydroxide in the nanoparticles synthesis, releases H+ and allows the reduction of silver ions (Ag+) in metallic silver (Ag-0).
- ItemSomente MetadadadosEfeitos da corticosterona sobre o comportamento de ratos no modelo da transição claro/escuro e sobre a imunorreatividade à proteína Delta-FOSB em áreas encefálicas, relacionadas à modulação do estresse e da ansiedade(Universidade Federal de São Paulo (UNIFESP), 2017-05-11) Hirata, Rafael Yutaka Scalize [UNIFESP]; Viana, Milena de Barros [UNIFESP]; http://lattes.cnpq.br/3053794724319601; Universidade Federal de São Paulo (UNIFESP)The concept of stress is based on the observation that different types of environmental changes (external or internal) can threaten the homeostasis / allostasis of the organism, leading to a set of bodily changes that characterize the "general adaptation syndrome". In this sense, the term stress can be used both to identify events or circumstances that are perceived as aversive (stressors) and to describe a state induced by stressors (stress reaction). The goal of the latter is to maintain homeostasis / alostase, which includes a series of physiological responses such as endocrine and cardiovascular activation, which in themselves do not produce pathological changes. However, when aversive stimulation occurs for a prolonged period or exceeds the body's ability to maintain homeostasis / alostase, stress can lead to pathological sequelae. The objective of the present study was to investigate the effects of chronic corticosterone glucocorticoid treatment (CORT) on behavior (anxiety and locomotion) and neuronal activation pattern in areas related to stress modulation. Male Wistar rats(8 weeks) were submitted to CORT treatment (21 days, 200 mg slow release pellets) and were then tested in the light / dark transition model and open field. After the tests, the animals were euthanized and their brains processed for deltaFosB-ir analysis. The results obtained in the present study showed that the chronic treatment with CORT decreased the number of rearings in the open field model without altering the number of crossings or the anxiety measurements performed in the light/dark transition model. The data from the immunohistochemical analysis showed that different brain structures related to the modulation of the stress and motor behavior were activated by the chronic treatment with CORT: The cingulate cortex; The dorsolateral and ventrolateral septum; The central, medial, basolateral, basomedial and lateral amygdala; The paraventricular, dorsomedial and ventromedial hypothalamus; The dorsomedial, dorsolateral, lateral and ventrolateral periaquedutal gray matter; And the dorsal, lateral and ventral wings of the dorsal nucleus of the raphe and the median nucleus of the raphe. These results contribute to a better understanding of the effects of chronic treatment with CORT.
- ItemAcesso aberto (Open Access)Fatores modificáveis da degeneração macular relacionada à idade(Conselho Brasileiro de Oftalmologia, 2009-06-01) Torres, Rogil José De Almeida [UNIFESP]; Maia, Maurício [UNIFESP]; Muccioli, Cristina [UNIFESP]; Winter, Guilherme; Souza, Greyce Kelly De; Pasqualotto, Luca Rodrigo; Luchini, Andréa; Précoma, Dalton Bertolim; Hospital Angelina Caron; Universidade Federal de São Paulo (UNIFESP); Hospital de Olhos Oeste Paulista Serviço de Cirurgia Vitreorretiniana; Pontifícia Universidade Católica do Paraná; PUCPR; Centro Oftalmológico de Curitiba; PUCPR Departamento de CardiologiaThe authors present the main modifiable risk factors that may trigger and/or worsen age-related macular degeneration. Mechanisms of action related to these factors as well as preventive measures and intervention effectiveness are discussed.
- ItemAcesso aberto (Open Access)Frentes de ondas (wavefronts) e limites da visão humana Parte 1: fundamentos(Conselho Brasileiro de Oftalmologia, 2002-12-01) Jankov, Mirko [UNIFESP]; Mrochen, Michael; Schor, Paulo [UNIFESP]; Chamon, Wallace [UNIFESP]; Seiler, Theo; UniversitätsSpital Zürich; Universidade Federal de São Paulo (UNIFESP); Instituto de Física AplicadaLight spreads out uniformly at the same speed in all directions. Its position at any given moment is a sphere that connects all the corresponding phase points, having the source at its center. Such imaginary spherical surfaces are called light fronts or wavefronts. There are three principal factors that limit the finest details an eye can see: optical (due to scattering, diffraction, chromatic and monochromatic aberration), retinal and neural factors (limiting visual acuity to an approximate maximum of 20/10 or 2.0). A mathematical system, the Zernike polynomials, can define geometrical surfaces in order to describe the monochromatic aberrations, both for the lower order aberrations ('prism', 'sphere' and 'astigmatism') and the higher order ones ('coma', 'spherical aberration' and others). The wavefront measures the performance of the whole optical system of the eye. Both systems described herein, the aberrometer based on the Tscherning principle and the one originated from the Hartmann-Shack sensor, start from the same logic: to compare the actual position of the wavefronts with the ideal one, calculate mathematically the geometrical surface that describes that discrepancy and represent it in the terms of the Zernike polynomials. Corneal topography measurement, with adequate software, can also express the wavefront, caused by the corneal irregularities, with the Zernike polynomials, but it still represents the anterior corneal surface only. Wavefront technology offers a new way to quantify and classify optical imaging errors of the human eye. The next article will deal with the peculiarities of the wavefront analysis, as well as with some of the clinical and surgical applications to the day-to-day ophthalmic practice.
- ItemAcesso aberto (Open Access)Frentes de ondas (wavefronts) e limites da visão humana Parte 2: aplicações(Conselho Brasileiro de Oftalmologia, 2002-12-01) Jankov, Mirko [UNIFESP]; Mrochen, Michael; Schor, Paulo [UNIFESP]; Chamon, Wallace [UNIFESP]; Seiler, Theo; UniversitätsSpital Zürich; Universidade Federal de São Paulo (UNIFESP); Instituto de Física AplicadaThe mean values for all the Zernike coefficients are approximately zero, while the individual variability is very high, what means that humans as a species in general have a very good optical system, though individually imperfect. Some temporal instability of higher-order aberrations, whose largest source is accommodation has been described. There arises a new question: will the correction of all the aberrations for the non-accommodated state of the eye be as beneficial for the near sight also? It is possible to modify and decrease the optical aberrations by a process of photo-ablation carried out by a scanning spot LASER with the wavefront data serving as a basis for the customized ablation profile. Perfect alignment of the LASER beam on the eye by means of high frequency eye trackers is fundamental. The theoretical visual benefit by correcting the higher order aberrations is up to 12 times. The main goal of the wavefront-guided treatments is not to allow the decrease in visual acuity after refractive surgical treatments, as may occur nowadays with the traditional LASER treatments; the next step would be treatments aiming at the improvement of visual acuity, as well as the treatments of highly irregular corneas (primary irregular, small or decentered ablations, central islands or irregularities after corneal transplantation). Understanding the new terminology and the bases of the new technological evolution, together with the continuous and critical follow-up of the new results in the literature, is the key of success of the modern approach to the problems related to refraction and refractive surgery.
- ItemSomente MetadadadosSaliva and light as templates for the green synthesis of silver nanoparticles(Elsevier B.V., 2014-01-20) Matos, Ricardo Almeida de [UNIFESP]; Courrol, Lilia Coronato [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)We report a method for the synthesis of silver nanoparticles using an aqueous saliva solution and irradiation with light from a mercury metal halide lamp. Bi-deionized water was used as the solvent, and surfactants or reducing agents were substituted by saliva and light in the procedure, characterizing the process as a green synthesis. the light was used to reduce silver ions (Ag+) to metallic silver (Ag-0). the average size, size distribution, and morphology of the nanoparticles were determined by transmission electron microscopy (TEM), UV/visible absorption spectrophotometry and Fourier transform infrared spectroscopy (FTIR). Spherical nanoparticles of similar to 20 nm in size were present after the lamp illumination. This methodology represents a non-invasive approach for disease detection and possesses a good potential for diagnostics applications. (C) 2013 Elsevier B.V. All rights reserved.