Página 1 dos resultados de 19577 itens digitais encontrados em 0.005 segundos

Decyl acetate synthesis by enzyme catalysis in sc-CO2

Rebocho, Sílvia F.; Ribeiro, Adriano S.; Ferreira, Olga; Oliveira, Manuela V.; Vidinha, Pedro; Barreiros, Susana; Macedo, Eugénia A.; Loureiro, José M.
Fonte: CHEMPOR Publicador: CHEMPOR
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
350.2733%
The synthesis of decyl acetate, from the transesterification of vinyl acetate with decanol, was studied in a high-pressure experimental set-up, equipped with a variable volume batch reactor, operating isothermally at 35 ºC and 100 bar, using CO2 in supercritical conditions as solvent, and Candida antarctica lipase B (CALB), immobilized on the macroporous resin Lewatit B (Novozym 435®), as catalyst. The enzymatic content was determined for each particle size of the catalyst. It was shown that the smallest particles have a larger specific amount of enzyme, and the results indicate that the enzyme is located in an external shell of the particle, following an “egg-shell” model type, with a thickness of ca. 60 μm (assuming a homogeneous distribution), independent of the particle size. Both external and internal mass transfer resistances were evaluated. External resistances were easily eliminated by stirring and internal diffusional limitations can be considered as negligible. The effect of the feed concentration of substrates on the initial reaction rate was also studied. It was observed that, above a certain concentration of decanol in excess relatively to vinyl acetate, the reaction is inhibited by the alcohol. On the contrary...

Enantioselective HPLC-UV method for determination of eslicarbazepine acetate (BIA 2-093) and its metabolites in human plasma

Alves, Gilberto; Figueiredo, Isabel; Castel-Branco, Margarida; Loureiro, Ana; Fortuna, Ana; Falcão, Amílcar; Caramona, Margarida
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
350.2733%
Eslicarbazepine acetate (BIA 2-093) is a novel central nervous system drug undergoing clinical phase III trials for epilepsy and phase II trials for bipolar disorder. A simple and reliable chiral reversed-phase HPLC-UV method was developed and validated for the simultaneous determination of eslicarbazepine acetate, oxcarbazepine, S-licarbazepine and R-licarbazepine in human plasma. The analytes and internal standard were extracted from plasma by a solid-phase extraction using Waters Oasis® HLB cartridges. Chromatographic separation was achieved by isocratic elution with water–methanol (88:12, v/v), at a flow rate of 0.7 mL/min, on a LichroCART 250-4 ChiraDex (β-cyclodextrin, 5 μm) column at 30°C. All compounds were detected at 225 nm. Calibration curves were linear over the range 0.4–8 μg/mL for eslicarbazepine acetate and oxcarbazepine, and 0.4 – 80 μg/ mL for each licarbazepine enantiomer. The overall intra- and interday precision and accuracy did not exceed 15%. Mean relative recoveries varied from 94.00 to 102.23% and the limit of quantification of the assay was 0.4 μg/mL for all compounds. This method seems to be a useful tool for clinical research and therapeutic drug monitoring of eslicarbazepine acetate and its metabolites S-licarbazepine...

Transport of solutes through calix[4]pyrrole-containing cellulose acetate films

Valente, A. J. M.; Jiménez, A.; Simões, A. C.; Burrows, H. D.; Polishchuk, A. Ya.; Lobo, V. M. M.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
350.2733%
Films of cellulose acetate containing different concentrations of meso-octamethyl-porphyrinogen (calix[4]pyrrole) were prepared and characterized using UV-vis and FTIR spectroscopy, DSC and SEM. Incorporation of calix[4]pyrrole into cellulose acetate leads to a decrease in the degree of hydrophilicity of the polymeric matrix. However, a slight increase in the percentage of water uptake of the polymer is found with an increase of the initial amount of calix[4]pyrrole in the composite composition. This effect can be related to the plasticizing effect that the calix[4]pyrrole provokes in the cellulose acetate. A comparative study of transport parameters of oxygen and some non-associated electrolytes (sodium, copper(II) and nickel chlorides) was carried out. The diffusion coefficients of molecular oxygen through cellulose acetate films decrease with an increase of the concentration of calix[4]pyrrole in the composite films. The transport (diffusion and permeation) of the above mentioned electrolytes through a set of composite films shows a decrease of permeability and diffusion coefficients with an increase of calix[4]pyrrole concentration. Such behaviour is typical of systems where interactions between the polymer and diffusing species occur. However...

Permeation of water as a tool for characterizing the effect of solvent, film thickness and water solubility in cellulose acetate membranes

Valente, Artur J. M.; Polishchuk, Alexandre Ya.; Burrows, Hugh D.; Lobo, Victor M. M.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
351.4995%
Cellulose acetate membranes have been used in many applications; of particular interest are reverse osmosis systems, and as a neutral matrix for incorporation of different polymers (e.g., conducting polymers), inorganic ions (e.g., lanthanides) and organic (e.g., pharmaceutical) compounds. The properties of the new polymers derived from cellulose acetate or blends depend on those of cellulose acetate. This work presents an attempt to find links between thermodynamic and kinetic properties of cellulose acetate membranes in equilibrium with water. Water diffusion coefficients in cellulose acetate membranes are reported, measured with a simple water permeation technique. The comparison of these values with the percentage of water uptake and polymer thickness leads to interesting conclusions related with different polymer properties.; http://www.sciencedirect.com/science/article/B6TWW-4DVBFCN-7/1/63e48f8aac1513c35feeaa6c746621e1

Solution behavior and surface properties of carboxymethylcellulose acetate butyrate

AMIM JR., Jorge; PETRI, Denise F. S.; MAIA, Francisco C. B.; MIRANDA, Paulo Barbeitas
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
350.2733%
Solution behavior of carboxymethylcellulose acetate butyrate (CMCAB) in acetone and ethyl acetate has been investigated by small-angle X-ray scattering (SAXS) and capillary viscometry and correlated with the characteristics of CMCAB films. Viscosity and SAXS measurements showed that ethyl acetate is a better solvent than acetone for CMCAB. Thin films of CMCAB were deposited onto silicon wafers (Si/SiO(2)) by spin coating. AFM images revealed that CMCAB spin coated films from solutions prepared in ethyl acetate were homogeneous and flat. However, films obtained from solutions in acetone were very rough. Contact angle measurements with polar and apolar test liquids characterized CMCAB surfaces as hydrophobic and allowed estimating the surface energy of CMCAB. Sum frequency generation vibrational spectroscopy was used to understand the role played by solvents and to gain insight about molecular orientation at Si/SiO(2)/CMCAB interface.; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CNPq; FAPESP; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characteristics of thin cellulose ester films spin-coated from acetone and ethyl acetate solutions

AMIM JR., J.; KOSAKA, P. M.; PETRI, D. F. S.
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
351.4995%
Spin-coated films of cellulose acetate (CA), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB) and carboxymethylcellulose acetate butyrate (CMCAB) have been characterized by ellipsometry, atomic force microscopy (AFM) and contact angle measurements. The films were spin-coated onto silicon wafers, a polar surface. Mean thickness values were determined by means of ellipsometry and AFM as a function of polymer concentration in solutions prepared either in acetone or in ethyl acetate (EA), both are good solvents for the cellulose esters. The results were discussed in the light of solvent evaporation rate and interaction energy between substrate and solvent. The effects of annealing and type of cellulose ester on film thickness, film morphology, surface roughness and surface wettability were also investigated.

Biocompósitos a partir de celulose de linter: filmes de acetatos de celulose/celulose e quitosana/celulose; Biocomposites from linters cellulose: cellulose acetate/cellulose and chitosan/cellulose films

Morgado, Daniella Lury
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/12/2009 PT
Relevância na Pesquisa
352.4591%
O presente trabalho visou o estudo da modificação química da celulose de linter (obtida de fonte de rápido crescimento e considerada a celulose de maior pureza isolada de fontes vegetais) através da sua derivatização em meio homogêneo, buscando-se a obtenção de materiais com características bem definidas e via um método que apresente boa reprodutibilidade. Dentre os derivados de celulose, os acetatos têm importância industrial significativa. No presente trabalho, acetatos de celulose obtidos no sistema de solvente cloreto de lítio/dimetilacetamida (LiCl/DMAc), com diferentes graus de substituição (GS) foram caracterizados através de 1H NMR, espectroscopia na região do infravermelho, viscosimetria e análises térmicas (DSC e TG). Através de métodos quantitativos aplicados às curvas termogravimétricas pode-se obter parâmetros cinéticos relacionados à decomposição térmica como a energia de ativação (Ea). Os resultados para os acetatos mostraram que conforme o GS aumenta, aumenta o grau de substituição de C2 e C3, e observa-se também aumenta Ea. Acetatos de celulose com diferentes GS foram utilizados para a obtenção de filmes a partir do mesmo sistema de solvente. Visando à obtenção de biocompósitos...

Efeito do acetato de chumbo associado ou não ao sulfato ferroso em cérebro de ratos: análise das enzimas antioxidantes; Effect of lead acetate with or without iron sulfate in brain of rats: Analysis of antioxidant enzymes

Ferreira, Maria Cecilia de Freitas
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/09/2012 PT
Relevância na Pesquisa
351.4995%
O chumbo (Pb) é um metal pesado, tóxico e está presente em diversos sistemas biológicos. Quando absorvido pelo organismo na forma iônica (Pb2+) atua em vários órgãos e sistemas, podendo ocasionar alterações graves no sistema nervoso central. Em adição, tem sido relatado que o íon ferroso (Fe2+) pode apresentar, entre outros, um efeito protetor na neurotoxicidade causada pelo Pb2+. Portanto, o objetivo deste estudo foi avaliar os marcadores de estresse oxidativo no cérebro de ratos expostos com acetato de chumbo (Pb(C2H3O2)2) associado ou não ao sulfato ferroso (FeSO4). Assim, 36 ratos machos (Rattus norvergicus) recém desmamados, divididos em 6 grupos (G), de 6 animais cada, foram expostos durante 6 semanas. No grupo controle (G1) os animais ingeriram água deionizada; G2 e G3 receberam 0,26 mM e G4 e G5 1,05 mM de acetato de chumbo, somado a isso G3 e G5 foram suplementados com 20 mg de sulfato ferroso/Kg peso corporal a cada 2 dias; e para G6 utilizou-se água deionizada e sulfato ferroso. O cérebro dos animais foi coletado para a análise da atividade enzimática de catalase (CAT), superóxido dismutase (SOD), glutationa peroxidase (GPx), a concentração de glutationa reduzida (GSH)...

Effect of cyproterone acetate on alpha1-adrenoceptor subtypes in rat vas deferens

Campos, M.; Morais, P.L.; Pupo, A.S.
Fonte: Associação Brasileira de Divulgação Científica (ABRADIC) Publicador: Associação Brasileira de Divulgação Científica (ABRADIC)
Tipo: Artigo de Revista Científica Formato: 1571-1581
ENG
Relevância na Pesquisa
352.4591%
Gonadal hormones regulate the expression of alpha1-adrenoceptor subtypes in several tissues. The present study was carried out to determine whether or not cyproterone acetate, an anti-androgenic agent, regulates the alpha1-adrenoceptor subtypes that mediate contractions of the rat vas deferens in response to noradrenaline. The actions of subtype selective alpha1-antagonists were investigated in vas deferens from control and cyproterone acetate-treated rats (10 mg/day, sc, for 7 days). Prazosin (pA2 ~9.5), phentolamine (pA2 ~8.3) and yohimbine (pA2 ~6.7) presented competitive antagonism consistent with activation of alpha1-adrenoceptors in vas deferens from both control and treated rats. The pA2 values estimated for WB 4101 (~9.5), benoxathian (~9.7), 5-methylurapidil (~8.5), indoramin (~8.7) and BMY 7378 (~6.8) indicate that alpha1A-adrenoceptors are involved in the contractions of the vas deferens from control and cyproterone acetate-treated rats. Treatment of the vas deferens from control rats with the alpha1B/alpha1D-adrenoceptor alkylating agent chloroethylclonidine had no effect on noradrenaline contractions, supporting the involvement of the alpha1A-subtype. However, this agent partially inhibited the contractions of vas deferens from cyproterone acetate-treated rats...

Effects of mutations in acetate metabolism on high-cell-density growth of Escherichia coli

Contiero, Jonas; Beatty, C.; Kumari, S.; DeSanti, C. L.; Strohl, W. R.; Wolfe, A.
Fonte: Nature America Inc Publicador: Nature America Inc
Tipo: Artigo de Revista Científica Formato: 421-430
ENG
Relevância na Pesquisa
353.86426%
To study the role played by acetate metabolism during high-cell-density growth of Escherichia coli cells, we constructed isogenic null mutants of strain W3100 deficient for several genes involved either in acetate metabolism or the transition to stationary phase. We grew these strains under identical fed-batch conditions to the highest cell densities achievable in 8 h using a predictive-plus-feedback-controlled computer algorithm that maintained glucose at a set-point of 0.5 g/l, as previously described. Wild-type strains, as well as mutants lacking the sigma(s) subunit of RNA polymerase (rpoS), grew reproducibly to high cell densities (44-50 g/l dry cell weights, DCWs). In contrast, a strain lacking acetate kinase (ackA) failed to reach densities greater than 8 g/l. Strains lacking other acetate metabolism genes (pta, acs, poxB, iciR, and fadR) achieved only medium cell densities (15-21 g/l DCWs). Complementation of either the acs or the ackA mutant restored wild-type high-cell-density growth, on a dry weight basis, poxB and fadR strains produced approximately threefold more acetate than did the wild-type strain. In contrast, the pta, acs, or rpoS strains produced significantly less acetate per cell dry weight than did the wild-type strain. Our results show that acetate metabolism plays a critical role during growth of E. coli cultures to high cell densities. They also demonstrate that cells do not require the sigma(s) regulon to grow to high cell densities...

Estudo de bioequivalencia entre duas formulações contendo 2 mg de acetato de ciproterona e 0,035 mg de etinilestradiol em voluntarias sadias atraves de cromatografia liquida acoplada a espectrometria de massas; Bioequivalence study of two formulations with 2 mg of cyproterone acetate and 0,35 mg ethynilestradiol in healthy volunteers by high-performance liquid coupled to mass spectrometry

Ana Cristina Mazuqueli
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/07/2008 PT
Relevância na Pesquisa
352.4591%
O objetivo deste estudo foi avaliar a bioequivalência de duas formulações de acetato de ciproterona e etinilestradiol em drágea vs comprimido (Selene® comprimidos, Laboratório Eurofarma Ltda., formulação Teste e Diane® 35, Schering do Brasil, como Referência) após administração oral em 48 voluntárias adultas sadias. O estudo foi do tipo aberto, randomizado com duas fases, em que as voluntárias receberam uma dose única de acetato de ciproterona 2mg e etinilestradiol 0,035mg . As amostras de plasma foram obtidas em um período total de 240h. As concentrações plasmáticas de acetato de ciproterona e etinilestradiol foram analisadas por um método baseado na cromatografia líquida acoplada ao espectrômetro de massa usando como fonte de ionização photospray ( LC-MS/MS ) utilizando finasterida como padrão interno do acetato de ciproterona e 17-a-etinilestradiol-D4 como padrão interno do etinilestradiol. A concentração plasmática do acetato de ciproterona não teve diferença significante após a administração de ambas as formulações (formulação teste e referência do Diane®35). A média geométrica da razão entre o medicamento teste e referência com 90% IC, foi 90,66% (84,39% - 97,40% ) para Cmax, 96,20% (90...

Desenvolvimento e caracterização de nanofibras de acetato de celulose para liberação controlada de fármacos; Development and characterization of cellulose acetate nanofibers for controlled release of drugs

Silvia Vaz Guerra Nista
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/02/2012 PT
Relevância na Pesquisa
353.23055%
Este projeto foi desenvolvido em duas fases, usando a tecnologia de eletrofiação. A primeira fase foi dedicada a obtenção de membranas eletrofiadas com acetato de celulose, as quais formaram nanofibras que foram carregadas com Sulfato de gentamicina, na segunda fase, para estudos da liberação controlada deste fármaco. Na primeira fase as membranas de nanofibras de Acetato de Celulose, chamadas de nanomembranas, foram produzidas utilizando-se quatro misturas de solventes (Acido Acético/Água (75:25 m/m), Acetona/Água (85:15 m/m), Dimetilacetamida (DMAc)/Acetona (1:2 m/m), Dimetilacetamida/Acetona/Água (32/63/5 m/m)). Usando a ferramenta de planejamento de experimentos (DOE), foram definidos os melhores parâmetros para preparação das membranas nanoestruturadas, em cada sistema de solvente. Três variáveis, sendo a distância entre a agulha e o coletor, a concentração de acetato de celulose na solução e a tensão aplicada, em dois níveis (alto e baixo), foram estudadas em cada sistema. As respostas avaliadas para obtenção da melhor condição, em cada caso, foram o diâmetro médio da fibra obtida e aspecto da membrana formada. Foi realizado também, no sistema de solvente Acido Acético/Água (70:30 m/m), um comparativo entre fiação horizontal...

Biocompósitos de acetato de celulose e fibras curtas de Curauá; Biocomposites of cellulose acetate and short Curauá fibers

Miguel Chávez Gutiérrez
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 18/07/2011 PT
Relevância na Pesquisa
351.4995%
Neste trabalho foram desenvolvidos biocompósitos baseados em acetato de celulose e fibras curtas de Curauá. Os compósitos foram preparados por extrusão em escala laboratorial e piloto, sendo estudada a influência do processamento, teor de fibras, teor e tipo de plastificante e tratamento das fibras, sobre as propriedades mecânicas e térmicas. As fibras foram tratadas com solução alcalina ou submetidas à extração com acetona. O tratamento das fibras com solução alcalina resultou em mudanças na rugosidade e do diâmetro das fibras, além da remoção parcial de hemicelulose e lignina. Já as fibras extraídas com acetona apresentaram principalmente uma diminuição do diâmetro. Biocompósitos reforçados com fibras tratadas apresentaram maior modulo elástico e maior condutividade térmica com relação aos compósitos reforçados com fibras não tratadas, sendo este efeito atribuído a uma melhor adesão interfacial. Dentre os plastificantes utilizados, o ftalato de dioctila (DOP) ou citrato de trietila (TEC), o DOP mostrou-se mais eficiente, causando uma diminuição mais acentuada da temperatura de transição vítrea (Tg) e do módulo elástico, resultando em materiais com maior resistência ao impacto em relação as formulações plastificadas com TEC. Os biocompósitos preparados em escala piloto apresentaram maior ganho do módulo elástico com relação à matriz plastificada e maior resistência ao impacto...

The mechanism of formation of 8,8-dimethyl[4.2.1.0 3,7]nonan-6-yl acetate (fortesyl acetate) during acetolysis of nopyl toluene-psulfonate

Al-Qallaf, Fawzia A. H.; Fortes, A. Gil; Johnstone, Robert A. W.; Thompson, Ian; Whittaker, David
Fonte: Royal Society of Chemistry Publicador: Royal Society of Chemistry
Tipo: Artigo de Revista Científica
Publicado em //1999 ENG
Relevância na Pesquisa
351.4995%
Attempts to prepare 2-(2-hydroxyethyl)-6,6-dimethylbicyclo[3.1.1]hept-2-ene (nopol; 1) labelled with deuterium at C-10 by a process of oxidation of the primary alcohol group of nopol to the aldehyde, followed by H/D exchange and reduction back to alcohol, were unsuccessful because various oxidation procedures, including reaction with N-chlorosuccinimide at 278 8C, gave instead a carboxylic acid having an oxygen at C-3. Nopol, labelled at C-11 with deuterium, was obtained through a Prins reaction of b-pinene with deuteriated paraformaldehyde. This labelled nopol was converted into its toluene-p-sulfonate ester, and was solvolysed in acetic acid containing acetate ion to give 8,8-dimethyltricyclo[4.2.1.03,7]nonan-6-yl acetate, which is an earlier reported novel fused ring system (fortesyl acetate; 2 acetate). The position of the label in the product showed that the mechanism of this deep-seated carbon skeletal rearrangement proceeds through the intermediate formation of a cyclobutane ring, followed by shift of a methylene bridge to expand the original cyclobutane ring and then subsequent expansion of the new cyclobutane ring. Calculations of heats of formation of possible ions involved in these shifts confirm the proposed mechanism as the most likely pathway.; Junta Nacional de Investigação Científica e Tecnológica. Kuwait. Eschenmoser Trust UK.

Ady2p is essential for the acetate permease activity in the yeast Saccharomyces cerevisiae

Paiva, Sandra; Devaux, Frederic; Barbosa, Sónia; Jacq, Claude; Casal, Margarida
Fonte: John Wiley & Sons, Ltd. Publicador: John Wiley & Sons, Ltd.
Tipo: Artigo de Revista Científica
Publicado em /02/2004 ENG
Relevância na Pesquisa
352.4591%
To identify new genes involved in acetate uptake in Saccharomyces cerevisiae, an analysis of the gene expression profiles of cells shifted from glucose to acetic acid was performed. The gene expression reprogramming of yeast adapting to a poor non-fermentable carbon source was observed, including dramatic metabolic changes, global activation of translation machinery, mitochondria biogenesis and the induction of known or putative transporters. Among them, the gene ADY2/YCR010c was identified as a new key element for acetate transport, being homologous to the Yarrowia lipolytica GPR1 gene, which has a role in acetic acid sensitivity. Disruption of ADY2 in S. cerevisiae abolished the active transport of acetate. Microarray analyses of ady2 strains showed that this gene is not a critical regulator of acetate response and that its role is directly connected to acetate transport. Ady2p is predicted to be a membrane protein and is a valuable acetate transporter candidate.

Acetate-induced apoptosis in colorectal carcinoma cells involves lysosomal membrane permeabilization and cathepsin D release

Marques, Carolina; Oliveira, C. Suellen F.; Alves, Sara; Chaves, S. R.; Coutinho, O. P.; Côrte-Real, Manuela; Preto, Ana
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 21/02/2013 ENG
Relevância na Pesquisa
353.23055%
Colorectal carcinoma (CRC) is one of the most common causes of cancer-related mortality. Short-chain fatty acids secreted by dietary propionibacteria from the intestine, such as acetate, induce apoptosis in CRC cells and may therefore be relevant in CRC prevention and therapy. We previously reported that acetic acid-induced apoptosis in Saccharomyces cerevisiae cells involves partial vacuole permeabilization and release of Pep4p, the yeast cathepsin D (CatD), which has a protective role in this process. In cancer cells, lysosomes have emerged as key players in apoptosis through selective lysosomal membrane permeabilization (LMP) and release of cathepsins. However, the role of CatD in CRC survival is controversial and has not been assessed in response to acetate. We aimed to ascertain whether LMP and CatD are involved in acetate-induced apoptosis in CRC cells. We showed that acetate per se inhibits proliferation and induces apoptosis. More importantly, we uncovered that acetate triggers LMP and CatD release to the cytosol. Pepstatin A (a CatD inhibitor) but not E64d (a cathepsin B and L inhibitor) increased acetateinduced apoptosis of CRC cells, suggesting that CatD has a protective role in this process. Our data indicate that acetate induces LMP and subsequent release of CatD in CRC cells undergoing apoptosis...

Effect of cyproterone acetate on alpha1-adrenoceptor subtypes in rat vas deferens

Campos,M.; Morais,P.L.; Pupo,A.S.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2003 EN
Relevância na Pesquisa
352.4591%
Gonadal hormones regulate the expression of alpha1-adrenoceptor subtypes in several tissues. The present study was carried out to determine whether or not cyproterone acetate, an anti-androgenic agent, regulates the alpha1-adrenoceptor subtypes that mediate contractions of the rat vas deferens in response to noradrenaline. The actions of subtype selective alpha1-antagonists were investigated in vas deferens from control and cyproterone acetate-treated rats (10 mg/day, sc, for 7 days). Prazosin (pA2 ~9.5), phentolamine (pA2 ~8.3) and yohimbine (pA2 ~6.7) presented competitive antagonism consistent with activation of alpha1-adrenoceptors in vas deferens from both control and treated rats. The pA2 values estimated for WB 4101 (~9.5), benoxathian (~9.7), 5-methylurapidil (~8.5), indoramin (~8.7) and BMY 7378 (~6.8) indicate that alpha1A-adrenoceptors are involved in the contractions of the vas deferens from control and cyproterone acetate-treated rats. Treatment of the vas deferens from control rats with the alpha1B/alpha1D-adrenoceptor alkylating agent chloroethylclonidine had no effect on noradrenaline contractions, supporting the involvement of the alpha1A-subtype. However, this agent partially inhibited the contractions of vas deferens from cyproterone acetate-treated rats...

SAGA complex components and acetate repression in Aspergillus nidulans

Georgakopoulos, P.; Lockington, R.; Kelly, J.
Fonte: Genetics Society of America Publicador: Genetics Society of America
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
354.39406%
Alongside the well-established carbon catabolite repression by glucose and other sugars, acetate causes repression in Aspergillus nidulans. Mutations in creA, encoding the transcriptional repressor involved in glucose repression, also affect acetate repression, but mutations in creB or creC, encoding components of a deubiquitination system, do not. To understand the effects of acetate, we used a mutational screen that was similar to screens that uncovered mutations in creA, creB, and creC, except that glucose was replaced by acetate to identify mutations that were affected for repression by acetate but not by glucose. We uncovered mutations in acdX, homologous to the yeast SAGA component gene SPT8, which in growth tests showed derepression for acetate repression but not for glucose repression. We also made mutations in sptC, homologous to the yeast SAGA component gene SPT3, which showed a similar phenotype. We found that acetate repression is complex, and analysis of facA mutations (lacking acetyl CoA synthetase) indicates that acetate metabolism is required for repression of some systems (proline metabolism) but not for others (acetamide metabolism). Although plate tests indicated that acdX- and sptC-null mutations led to derepressed alcohol dehydrogenase activity...

Produção e caracterização de fibras eletrofiadas de acetato de celulose com propriedades funcionais obtidas pela incorporação de lignina e óleo essencial de citronela; Production and characterization of cellulose acetate electrospun fibers with functional properties obtained by incorporation of lignin and citronella essential oil

João Vinícios Wirbitzki da Silveira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/11/2014 PT
Relevância na Pesquisa
352.4591%
A técnica de eletrofiação tem sido foco de muitas pesquisas na última década. O uso do acetato de celulose na produção de fibras nas escalas micro e nanométrica provou ser adequado, uma vez que é possível produzir fibras continuamente com diâmetros extremamente pequenos. Neste trabalho, as fibras de acetato de celulose foram produzidas pela técnica de eletrofiação com distribuição de tamanho de diâmetros inferiores a 1 μm. Foram empregados dois diferentes sistemas de solventes baseados em uma mistura de acetona/água e acetona/N,N-dimetil-acetamida. Para criar diferentes funcionalidades para essas fibras, compostos naturais - lignina organosolv (Alcell) e óleo essencial de citronela - foram incorporados ao acetato de celulose. Para a caracterização das soluções foram empregadas medições de viscosidade, condutividade elétrica e tensão superficial. As fibras foram visualizadas com o auxílio das microscopias eletrônicas de varredura (MEV) e de transmissão (MET). Os ensaios físicos e mecânicos avaliados se concentram na medição do ângulo de contato com a água (WCA) e o uso de ensaio de tração mecânica. As análises térmicas dos materiais foram realizadas empregando-se calorimetria diferencial exploratória (DSC) e análise termogravimétrica (TG). As matérias-primas foram analisadas com intuito de justificar os comportamentos observados nas fibras. A estrutura química da lignina foi estudada: distribuição de massa molar...

Calcium acetate versus calcium carbonate in the control of hyperphosphatemia in hemodialysis patients

d'Almeida Filho,Eufrônio José; Cruz,Elisa de Albuquerque Sampaio da; Hoette,Marcos; Ruzany,Frederico; Keen,Luana Neves Lopes; Lugon,Jocemir Ronaldo
Fonte: Associação Paulista de Medicina - APM Publicador: Associação Paulista de Medicina - APM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2000 EN
Relevância na Pesquisa
352.4591%
CONTEXT: Hyperphosphatemia has an important role in the development of bone and mineral abnormalities in end-stage renal disease (ESRD). OBJECTIVE: To compare the phosphorus binding power and the hypercalcemic effect of calcium acetate and calcium carbonate in hemodialysis patients. TYPE OF STUDY: Crossover, randomized, double-blind study. PLACE: A private hospital dialysis center. PARTICIPANTS: Fifty-two patients who were undergoing regular hemodialysis three times a week ([Ca++] dialysate = 3.5 mEq/L). PROCEDURES: Half of the patients were started on 5.6 g/day of calcium acetate and, after a 2 week washout period, received 6.2 g/day of calcium carbonate. The other half followed an inverse protocol. MAIN MEASUREMENTS: Clinical interviews were conducted 3 times a week to monitor for side effects. Determinations of serum urea, calcium, phosphorus, hematocrit, Kt/V and blood gas analysis were obtained before and after each treatment. RESULTS: Twenty-three patients completed the study. A significant increase in calcium plasma levels was only observed after treatment with calcium carbonate [9.34 mg/dl (SD 0.91) vs. 9.91 mg/dl (SD 0.79), P < 0.01]. The drop in phosphorus levels was substantial and significant for both salts [5.64 mg/dl (SD 1.54) vs. 4.60 mg/dl (SD 1.32)...