993 resultados para Leitores - Reação critica
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The NbCl5 being a strong electrophile, is a potential candidate to act as a Lewis acid, and therefore it mediates various organic reactions. For this reason, it has received continuous attention by Brazilian researchers, especially in recent decades, since Brazil holds the largest reserves of niobium, besides being the largest producer of this element. The Michael addition reaction is one of the most widely used for forming carbon-carbon bonds and takes place by the addition of nucleophiles to activated olefins. Although this type of reaction is usually catalyzed by base, there are reports in the literature on the use of various Lewis acids in this type of reaction. The synthesis of enamines based acetilenodicarboxilates and amines, aromatic or alkyl, by Michael addition reaction is quite interesting, since these are valuable synthetic intermediates for the synthesis of heterocyclic and they are used in multicomponent reactions. The derivatives of anilino-fumarate also have a great potential for medical application. In this study we investigated the use of niobium pentachloride as Lewis acid to catalyze the Michael additions between the derivatives of aniline and acetilenodicarboxilates the synthesis of enamines
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Pós-graduação em Educação Escolar - FCLAR
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Pós-graduação em Química - IQ
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Proteção de Plantas) - FCA
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Letras - IBILCE
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Pós-graduação em Letras - FCLAS
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Benzodiazepines are one of the most frequently prescribed drugs due to their anxiolytic properties. The aim of this study was to evaluate the effects of diazepam on lipopolysaccharide-induced peritoneal acute inflammatory responses. Swiss mice were treated with diazepam in a single dose of 1 or 10 mg/kg- subcutaneously 1 h before an intraperitoneal injection of lipopolysaccharide or sterile saline solution. The mice were killed 16 h after and the cells were washed from the peritoneal cavity to determine the total number of cells and the mononuclear and polimorfonuclear subpopulations, as well as the TNF-alpha activity and percentage of spread macrophages. Our results showed that the diazepam treatment (1 and 10 mg/kg) induced a significant reduction in the LPS-induced macrophage stimulation and TNF-α activity. Diazepam (10 mg/kg) also reduced the inflammatory cellular migration when compared to the control. It can be concluded that the diazepam treatment in a single dose is able to influence the inflammatory cellular influx, macrophage stimulation and TNF-α activity in the acute inflammatory response in mice, having possible implications on the anti-infectious response efficiency.
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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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The present study evaluated the use of PCR for Histophilus somni detection in bovine semen. Semen samples were experimentally infected with H. somni at dilutions ranging from 107 to 101 bacteria/mL and subjected to DNA extraction by the phenol/chloroform method, followed by PCR amplification. The amplification products were analyzed by electrophoresis in 8% acrylamide gel. The oligonucleotide primers used yielded an amplification fragment of 400 base pairs from the bacterial DNA. Positive amplification was obtained even for the 101 bacteria/mL dilution. PCR proved to be an efficient method for the detection of H. somni. The results obtained in this study have brought relevant information for the diagnosis of H. somni, justifying the need for the diagnosis of this bacterium in bulls, especially in semen samples that should be free of contamination. The PCR method has shown to be a useful tool for the quality control of semen produced in artificial insemination centers.
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Indirect composite resin systems have been routinely recommended for making restorations in distressed patients. The purpose of this study was to evaluate histologically in rats the effect of chronic stress on the reaction of subcutaneous connective tissue after implant of Artglass™. For this purpose, 60 rats were divided into four groups (GI (control), GII (stressed), GIII (Artglass™) and GIV (Artglass™. / stressed) received dorsal subcutaneous implants of polyethylene tubes containing saline solution (GI and GII) or Artglass™ (GIII and GIV). In groups of four animals were sacrificed at 7,14 and 28 days postoperatively. The results allowed to observe more intense inflammatory reaction and tissue organization later in the animals subjected to stress.
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Physiological functions undergo a gradual retardation that begins around 25-30 years and extends to the death. Moreover, this change affects most severely the activities more complex and more intricate responses to tensions or stress. The purpose of this study was to evaluate histologically in aged rats the effect of chronic stress on the reaction of subcutaneous connective tissue. The purpose of this study was to evaluate histologically in aged rats the effect of chronic stress on the reaction of subcutaneous connective tissue. For this purpose, 60 rats were divided into four groups (GI (control), GII (stressed), GIII (elderly) and GIV (aged / stressed) received dorsal subcutaneous implants of polyethylene tubes containing saline solution. In groups of four animals were sacrificed at 7,14 and 28 days postoperatively. The results allowed to observe more intense inflammatory reaction and tissue organization later in the aged animals subjected to stress.
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Introdução: o objetivo do estudo foi avaliar a resposta do tecido subcutâneo de ratos a implantes de tubos de polietileno com cimento Portland modificado (CPM) (EGEO S.R.L., Buenos Aires, Argentina) comparado com o MTA Angelus® (Angelus, Londrina/PR). Métodos: esses materiais foram colocados em tubos de polietileno e implantados no tecido conjuntivo dorsal de ratos Wistar por 7, 15, 30, 60 e 90 dias. Os espécimes foram preparados e corados com hematoxilina e eosina ou Von Kossa, ou não corados por luz polarizada. Foram realizadas avaliações quantitativas e qualitativas das reações. Resultados: ambos os materiais causaram reações moderadas em 7 dias, decaindo com o tempo. O MTA Angelus causou reações leves em 15 dias, decaindo com o tempo. A resposta foi similar ao controle em 30, 60 e 90 dias com CPM e MTA Angelus. Foram observadas mineralização e granulações birrefringentes à luz polarizada em ambos os materiais. Conclusões: foi possível concluir que o CPM e o MTA Angelus foram biocompatíveis em modelo de rato e estimularam a mineralização.