82 resultados para cis-trans transitions
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Objective To describe the trans-cultural adaptation of the evaluation instrument entitled Atenció Sanitària de Les Demències: la visió de L' Atenció Primarià from Catalan into versions in Portuguese for doctors and nurses. This study evaluates the knowledge and perspectives of these professionals in their treatment of patients diagnosed with dementia in cases of primary care. Method The adaptation followed internationally accepted rules, which include the following steps: translation, synthesis, back-translation, revision by a committee of specialists, and a test run with 35 practicing doctors and 35 practicing nurses in Brazil's Family Health Strategy (Estratégia Saúde da Família, or ESF in Portuguese). Results The translation, synthesis, and back-translation steps were performed satisfactorily; only small adjustments were required. The committee of specialists verified the face validity in the version translated into Portuguese, and all of the items that received an agreement score lower than 80% during the initial evaluation were revised. In the test run, the difficulties presented by the health care professionals did not reach 15% of the sample, and therefore, no changes were made. Conclusion The Portuguese translation of the instrument can be considered semantically, idiomatically, culturally, and conceptually equivalent to the original Catalan version and is, therefore, appropriate for use in Brazil.
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O objetivo deste trabalho foi avaliar o efeito da aplicação de elicitores abióticos na biossíntese de resveratrol e na indução de resistência à podridão póscolheita de maçãs 'Gala' e 'Fuji'. Foram realizados os tratamentos: radiação ultravioleta, fosfito e acibenzolar-Smetil - aplicados antes do armazenamento - e ozônio - aplicado intermitente durante o armazenamento. As condições de armazenamento foram: 'Gala', 1,5 kPa de O2 e 2,5 kPa de CO2, a 0,5±0,1ºC, por oito meses, e 'Fuji', 1,0 kPa de O2 e <0,5 kPa de CO2, a 0,5±0,1ºC, por sete meses. O delineamento experimental foi inteiramente ao acaso, com oito repetições de 25 frutos. Na casca dos frutos, determinou-se: trans-resveratrol, polifenóis totais, antocianinas totais e diâmetro de lesão, após inoculação de Penicillium sp. no ferimento. Analisou-se na polpa: firmeza de polpa, acidez titulável, sólidos solúveis totais, açúcares redutores e nãoredutores. Os elicitores não alteram a concentração de polifenóis totais e antocianinas, com exceção do acibenzolar-Smetil que reduz o conteúdo de antocianinas na maçã 'Gala'. Os elicitores induzem, na 'Fuji', mas não na maçã 'Gala', a síntese de trans-resveratrol na seqüência: acibenzolar-Smetil> fosfito> irradiação UV-C> ozônio. Na maçã 'Gala', o fosfito reduz a ocorrência de podridão, porém, em ambas as cultivares, não há correlação entre síntese de trans-resveratrol e controle de podridão.
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O objetivo foi avaliar, por HPLC, a composição qualitativa e quantitativa de carotenoides em maracujás do cerrado. Frutos procedentes de acessos nativos de quatro espécies (Passiflora cincinnata, P. nitida, P. setacea e P. edulis) foram analisados, utilizando, como referência, o maracujá-amarelo comercial (P. edulis). As polpas de maracujá apresentaram neoxantina, violaxantina, cis-violaxantina, anteraxantina, luteína, zeaxantina, β-criptoxantina, poli-cis-caroteno, prolicopeno, cis-ζ-caroteno, trans-ζ-caroteno, trans-β-caroteno, 13-cis-β-caroteno e fitoflueno. Em geral, os teores de carotenoides entre as espécies e entre os acessos da mesma espécie foram significativamente diferentes. A espécie P. edulis apresentou o maior número de carotenoides, com diferença entre os acessos. Em um acesso de P. edulis comercial, foi encontrado o trans-β-caroteno como o carotenoide principal (7,8±0,8 µg g-1) e no outro o trans-ζ-caroteno (11,4±0,4 µg g-1). Dois acessos de P. edulis nativos do Cerrado apresentaram cis-ζ-caroteno como carotenoide majoritário (6,28±0,15 µg g-1 e 12,1±0,7 µg g-1, casca amarela e roxa, respectivamente). O perfil de carotenoides em frutos de espécies de maracujá apresentou diversidade de composição, com potencial de uso para melhoramento genético para agregar maior valor ao produto e estimular o seu consumo.
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The series of compounds cis-[Fe(CO)4(HgX)2], X=Cl,Br,I shows an octahedral geometry around the iron atom with the two HgX groups cis to each other. In this paper the assignment for the carbonyl stretching modes and the calculation of their force constants were performed on the basis of the Cotton-Krainhanzel model. Taking into account all the data from the IR, 199Hg NMR and UV-vis spectra it is possible to verify the influence of X on the electronic densities at the metallic centers.
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Chalcone (1) and its fluorinated derivatives 2-4, as well as their cyclic analogues 5-10, were synthesized through an aldol condensation reaction between the corresponding ketone and aldehyde. These compounds were characterized by IR, EIMS and ¹H and 13C NMR spectral data. Modern NMR techniques allowed us to conclude that the compounds obtained show E configuration. These techniques were also employed to investigate the equilibrium involving the s-cis and s-trans conformations of 1-4, with this equilibrium being dependent on the fluorine substitution on both aromatic rings, A or B. IR studies indicated that the yield of the s-cis conformation in the fluorinated derivatives is 57.4±1.4; 88.1±0.4 and 66.4±0.7%, for 2, 3 and 4, respectively, based on previous ¹H NMR calculations for chalcone. Theoretical calculations, using the MMX method, were employed to justify the variation of chemical shifts for the fluorinated derivatives and cyclic analogues. These chemical shifts are consequence of the anisotropic effect showed by the carbonyl group on these compounds.
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In this article we review some of the basic aspects of rare earth spectroscopy applied to vitreous materials. The characteristics of the intra-atomic free ion and ligand field interactions, as well as the formalisms of the forced electric dipole and dynamic coupling mechanisms of 4f-4f intensities, are outlined. The contribution of the later mechanism to the 4f-4f intensities is critically discussed, a point that has been commonly overlooked in the literature of rare earth doped glasses. The observed correlation between the empirical intensity parameter W2 and the covalence of the ion first coordination shell is discussed accordingly to the theoretical predictions.
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Despite of being used as thermodynamic criterion to rank alkene stability in a number of undergraduate textbooks, the heat of hydrogenation does not describe adequately the relative stability of disubstituted alkenes. In this work, both the heat of formation and the heat of combustion were used as thermodynamic criteria to rank correctly the stability of alkenes according to the degree of alkyl substitution and also in the disubstituted series (geminal > trans > cis). An operational model based on molecular orbital and valence bond representations of hyperconjugation is proposed to show how this effect can explain the order of stability of this class of compounds.
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Nowadays the catalyst systems based on neodymium are the ones most used in the high cis polybutadiene production. These systems contain a neodymium compound (catalyst), an alkylaluminium compound (cocatalyst) and a halogen compound (halogenating agent). The microstructure, molecular weight characteristics and the reaction activity are influenced by the nature and concentration of catalyst system components. Those characteristics are also affected by the polymerization conditions. This paper presents a brief review on 1,4-cis-butadiene polymerization on neodymium catalysts.
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A matrix solid phase dispersion and gas chromatography-mass selective detection method for the simultaneous determination of monocrotophos, methyl parathion, cypermethrin and deltamethrin in okra is described. Analyses of 2 g of fortified okra (0.05-0.75 mg kg-1) showed an average recovery of 96.2% (71.4-128.4%) and average relative standard deviation of 11.7% (1.4-37.1%). The cypermethrin recovery at the lower level was above 130%. The limit of detection ranged from 0.02 to 0.15 mg kg-1. The procedure was applied to the okra samples and has found 0.56 mg kg-1 of cypermethrin-cis, 0.75 mg kg-1 of cypermethrin-trans and 2.71 mg kg-1 of deltamethrin.
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The thermal decomposition reaction of trans-3,6-dimethyl-3,6-diphenyl-1,2,4,5-tetraoxacyclohexane (acetophenone cyclic diperoxide, DPAF), in different solvents (methanol, 1,4-dioxane, acetonitrile and 2-propanol/benzene mixtures) in the initial concentration and temperature ranges of (4.2-10.5) x 10-3 M and 140.0 to 185.0 ºC, respectively, follows a pseudo first order kinetic law up to at least 70% DPAF conversion. An important solvent effect on the rate constant values, activation parameters (DH# and DS#) and reaction products obtained in different solvents is detected, showing that the reaction is accelerated in alcohols.
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The trans-dichlorobis(ethylenediamine)cobalt(III) chloride was synthesized in an undergraduate laboratory and its aquation reaction was carried out at different temperatures. This reaction follows pseudo-first-order kinetics and the rate constants, determined at 25, 35, 45, 55 and 70 º C, are 1.44 x 10-3; 5.14 x 10-3; 1.48 x 10-2; 4.21 x 10-2 and 2.21 x 10-1 s-1, respectively. The activation energy is 93.99 ± 2.88 kJ mol-1.
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Rate constants for the quenching of 1,3-indandione (1) triplet by olefins and by hydrogen and electron donors were obtained employing the laser flash photolysis technique in benzene solution. These rate constants ranged from 2.5x10(5) Lmol-1s-1 (for 2-propanol) to 5.9x10(9) Lmol-1s-1 (for DABCO). From the quenching rate constants by 1,3-cyclohexadiene, trans- and cis-stilbene a value between 49.3 and 52.4 kcal/mol was estimated for the energy of the triplet state of 1,3-indandione. The npi* character of this triplet state was evidenced by the quenching rate constants obtained when typical hydrogen donors were employed as quenchers. For 2-phenyl-1,3-indandione (2, R=phenyl) a fast Norrish type I reaction is operating which prevents the determination of kinetic and spectroscopic data of its triplet state.
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The function of lipids in human nutrition has been intensively debated in the last decade.This context reinforces the concern about controlling the trans fat ingestion, due to its negative implications on health. Interesterification provides an important alternative to modify the consistency of oils and fats without causing formation of trans isomers. This article reports research done towards production of zero trans fats by chemical interesterification, for different industrial purposes. Aspects related to the effect of trans fats on diet, their impact on health and modifications in Brazilian legislation are also covered.
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The chloroform extract of aerial parts of Ipomoea subincana was submitted to different chromatographic procedures which afforded methyl caffeate, ethyl caffeate, methyl 3,4-dimethoxycinnamate, lupeol, alpha-amyrin, beta-amyrin, 3-beta-O-beta-D-glycopiranosyl-sitosterol, beta-sitosterol, stigmasterol, scopoletin, aromadendrane-4beta,10alpha-diol, n-docosyl-cis-p-coumarate and n-icosyl-trans-p-coumarate, vanilin, cinamic acid and vanillic acid. However, from the ethyl acetate extract besides quercetin and 3-O-beta-D-glycopiranosyl-quercetin were isolated methyl 4-O-E-feruloyl-5-O-E-caffeoyl-quinate, methyl 3,5-di-O-E-caffeoyl-quinate and methyl 4-O-E-caffeoyl-quinate. The structures of the compounds were established on the basis of spectral data.
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The reaction of ten cis-octalins and cis-octalones with thallium trinitrate (TTN) leads to different products, depending mainly on the substitution pattern of the substrate. Functionalized cis-hydrindanes were obtained from the reaction of 1,2,3,4,4a,5,8,8a-octahydro-4a-methylnaphthalene and of 1,2,3,4,4a,5,8,8a-octahydro-4a,7-dimethylnaphthalene with TTN in acetonitrile, whereas a cyclic ether was formed treating 1,2,3,4,4a,5,8,8a-octahydro-6,8a-dimethylnaphthalen-1-ol with TTN in trimethylorthoformate (TMOF).