955 resultados para hydroxyl terminated polybutadiene


Relevância:

10.00% 10.00%

Publicador:

Resumo:

trans,trans-2,4-Decadienal (DDE) is an important breakdown product of lipid peroxidation. This aldehyde is cytotoxic to mammalian cells and is known to be implicated in DNA damage. Therefore, attempts were made in this work to assess the reactivity of DDE with 2'-deoxyadenosine (dAdo). It was shown that DDE is able to bind to 2'-deoxyadenosine, yielding highly fluorescent products. Besides 1,N-6-etheno-2'-deoxyadenosine (epsilon dAdo), two other related adducts, 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)3H-imidazo[2,1-i]purin-7-yl]-1,2,3-octanetriol and 1-[3-(2-deoxy-beta-D-erythro-pentofuranosyl)-3H-imidazo[2,1-i]purin-7-yl]-1,2-heptanediol, were isolated by reverse phase high-performance liquid chromatography and characterized on the basis of their UV, fluorescence, nuclear magnetic resonance, and mass spectrometry features. The reaction mechanism for the formation of the DDE-2'-deoxyadenosine adducts involves 2,4-decadienal epoxidation and subsequent addition to the N-2 amino group of 2'-deoxyadenosine, followed by cyclization at the N-1 site. Adducts differ by the length of carbon side chain and the number of hydroxyl groups. The present data indicate that DDE can be epoxidized by peroxides, and the resulting products are able to form several adducts with 2'-deoxyadenosine and/or DNA. Endogenous DNA adduct formation can contribute to the already reported high cytotoxicity of DDE to mammalian cells.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The potential of clear Ga2S3-GeS2-CsCl based sulfide glasses transparent up to 11.5 μm to be used as new optical material for multispectral applications has been investigated. The addition of large amount of chlorine ions – above 40 mol.% of CsCl – into the chalcogenide vitreous network in order to produce colorless glasses results in a drastic increase of their water contamination. We report for the first time, to the best of our knowledge, the purification of cesium chloride CsCl by dynamic distillations under vacuum in order to reduce water and hydroxyl group contamination before complete melting of the glass. Besides, sulfur purification by dynamic and static distillations was also performed in the implemented method. The obtained glasses were then characterized by UV-visible and infrared (FTIR) spectroscopies, by electron probe microanalysis (EPMA), thermal analysis (DSC), and their refractive indices in the visible and near infrared ranges were also measured. A large improvement of the glass transmission spectrum has been achieved with an estimated reduction of about 45 times of the OH and H2O content and 60 times of the SH content. The glass thermal molding ability and chemical durability with and without protective coating have been tested to probe their potential for fabrication of complex optics.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Comunicação - FAAC

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Química - IQ

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Química - IQ

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Educação - IBRC

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Water disinfection usually requires expensive chemicals or equipment. Chlorination is a common disinfection method, although it is not able to inactivate all pathogens. High concentrations of residual chlorine also cause an unpleasant taste and smell in drinking water. As an alternative, photocatalysis and photoelectrochemical treatment has a high disinfection potential in drinking water by using solid catalysts, such as titanium dioxide. Highly reactive hydroxyl radical generated during the process serves as the main oxidant, capable of inactivating a wide range of microorganisms. In this study, we proposed a novel comparison between Gram-positive and gram-negative microorganisms. An immobilized TiO2 film promoted higher efficiency in water disinfection processes. The treatment effectively inactivated Escherichia coli and Staphylococcus aureus bacterial microorganisms in a shorter period than other alternative methods.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

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

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Acute fatty liver of pregnancy is a rare disease that affects women in the third trimester of pregnancy. Although infrequent, the disease can cause maternal mortality. The diagnosis is not always clear until the pregnancy is terminated, and significant complications, such as acute pancreatitis, can occur. Pancreatic involvement typically only occurs in severe cases after the development of hepatic and renal impairment. To date, little knowledge is available regarding how the disease causes pancreatitis. Treatment involves supportive measures and pregnancy interruption. In this report, we describe a case of a previously healthy 26-year-old woman at a gestational age of 27 wk and 6 d who was admitted with severe abdominal pain and vomiting. This case illustrates the clinical and laboratory overlap between acute fatty liver of pregnancy and pancreatitis, highlighting the difficulties in differentiating each disease. Furthermore, the hypothesis for this overlapping is presented, and the therapeutic options are discussed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In the early vertebrate embryo, cardiac progenitor/precursor cells (CPs) give rise to cardiac structures. Better understanding their biological character is critical to understand the heart development and to apply CPs for the clinical arena. However, our knowledge remains incomplete. With the use of single-cell expression profiling, we have now revealed rapid and dynamic changes in gene expression profiles of the embryonic CPs during the early phase after their segregation from the cardiac mesoderm. Progressively, the nascent mesodermal gene Mesp1 terminated, and Nkx2-5+/Tbx5+ population rapidly replaced the Tbx5low+ population as the expression of the cardiac genes Tbx5 and Nkx2-5 increased. At the Early Headfold stage, Tbx5-expressing CPs gradually showed a unique molecular signature with signs of cardiomyocyte differentiation. Lineage-tracing revealed a developmentally distinct characteristic of this population. They underwent progressive differentiation only towards the cardiomyocyte lineage corresponding to the first heart field rather than being maintained as a progenitor pool. More importantly, Tbx5 likely plays an important role in a transcriptional network to regulate the distinct character of the FHF via a positive feedback loop to activate the robust expression of Tbx5 in CPs. These data expands our knowledge on the behavior of CPs during the early phase of cardiac development, subsequently providing a platform for further study.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Química - IQ