Results 1 - 10 of 7168
Results 1 - 10 of 7168. Search took: 0.029 seconds
|Sort by: date | relevance|
[en] Conditions in the malonic ester synthesis for various α-(11C-methyl)-carboxylic acids including 11CH3CH2CO2H were studied especially in view of rapidity and ease. The labelling provided to usually proceed fairly rapidly in a good yield. Also, 11CH3CH2CO2H was synthesized as an example of preparing (β-11C-ethyl)-ketones from β-diketones or acylacetic esters and 11CH3I. Some of the products are effectively used, together with corresponding 14C compounds, in metabolic studies by double tracer method. (author). 3 refs.; 1 fig.; 1 tab
[en] [1',3',4'-3H3]4-(5',6',7',8'-Tetrahydro-5',5',8',8'-tetramet hyl-2'-anthra-cenyl)benzoic acid (specific activity 64 Ci/mmole) was synthesized by bromination of ethyl 4-(5',6',7',8'-tetrahydro-5',5',8',8'-tetramethyl-2'-anthracenyl)benzoate, followed by reductive debromination by tritium gas in the presence of 10% palladium on carbon and hydrolysis. 1H and 3H NMR spectroscopy was used to establish tritium at 1',3',4'-tetrahydroanthracenyl ring positions. (Author)
[en] The X-ray structure of the tetragonal form of apo acyl-CoA-binding protein (ACBP) from the Harderian gland of the South American armadillo Chaetophractus villosus has been solved. The X-ray structure of the tetragonal form of apo acyl-CoA-binding protein (ACBP) from the Harderian gland of the South American armadillo Chaetophractus villosus has been solved. ACBP is a carrier for activated long-chain fatty acids and has been associated with many aspects of lipid metabolism. Its secondary structure is highly similar to that of the corresponding form of bovine ACBP and exhibits the unique flattened α-helical bundle (up–down–down–up) motif reported for animal, yeast and insect ACBPs. Conformational differences are located in loops and turns, although these structural differences do not suffice to account for features that could be related to the unusual biochemistry and lipid metabolism of the Harderian gland
[en] The objective of the current study was to assess the influence of a modified crushing process and kneading operation on the quality parameters, volatile compounds, and the fatty acid and sterol profiles of virgin olive oil from the Edremit yaglik variety. In the study, olive oil samples were produced in two different processes. The first one was produced without malaxation and the second one was produced with the malaxing process. During crushing, the effect of different temperatures was tested. The results demonstrate that different crushing temperatures generally did not affect the amount of free fatty acids, or peroxide value. Total phenol contents were positively affected by the additional malaxation process. Fatty acids and sterol composition were not significantly altered at different crushing temperatures or during the subsequent malaxation application. PCA enabled a clear classification of the oils obtained from different processing techniques.
[es]El objetivo del presente estudio fue evaluar la influencia de un proceso de molturación modificado y de la etapa de batido sobre los parámetros de calidad, los componentes volátiles, los ácidos grasos y el perfil de esteroles de aceites de oliva virgen de la variedad Edremit yaglik. En este estudio, las muestras de aceite de oliva se obtuvieron mediante dos procesos diferentes con y sin malaxación. Durante la trituración, se probó el efecto de diferentes temperaturas. Los resultados demostraron que las diferentes temperaturas de trituración, en general, no mostraron tener efecto sobre la cantidad de ácidos grasos libres o el índice de peróxido. El contenido total de fenoles se vio afectado positivamente por el empleo de malaxación. La composición de ácidos grasos y de esteroles no se vieron afectados significativamente por el aumento de la temperatura en la trituración ni durante el proceso de malaxación. PCA permitió una clasificación clara de los aceites obtenidos mediante las diferentes técnicas de procesamiento.
[en] The composition and distribution of fatty acids in triacylglycerol (TAG) molecules are commonly considered as factors that determine the physical properties of a given oil or fat. The distribution of any fatty acid in fats and oils can be described through the α coefficient of asymmetry, which can be calculated from the TAG composition and fatty acid composition of the Sn-2 position of the TAGs determined through lipase hydrolysis. High-oleic high-stearic oils and fats are considered stable and healthy, and they are good substitutes for hydrogenated vegetable oils and palm fractions in many food products, such as spreads and confectionery. Here, different high-oleic high-stearic acid oils were formulated which contained different distributions of saturated fatty acids in their TAGs, while maintaining a similar fatty acid composition. The aim of this work was to discuss the possibility of using the α coefficient to predict the physical properties of fats in function of their chemical composition and their melting and crystallization behavior as examined by differential scanning calorimetry.
[en] When mice were injected with 30 μmol of unlabeled succinate simultaneously with [2-3H] malate, [3-3H] β-OH-butyrate or [2-3H] acetate, a significant decrease in the incorporation into liver fatty acids was found only in animals injected with [2-3H] malate. After the mice were injected with [2-3H] malate and the liver di- or tri-carboxylic acids were isolated, the radioactivity was recovered principally in the lactic acid. When unlabeled succinate was added to the injection of [3H] malate, the percentage of radioactivity recovered decreased in the malate and increased in the lactate. The tritium of [2-3H] malate is more slowly incorporated into fatty acids than was that of [2,3-3H] succinate. The results, show that β-OH-butyrate is not a good source of hydrogen for fatty acid synthesis and that the most plausible explanation of the excellent incorporation of the hydrogen of succinate into fatty acids would be its passage from the mitochondria to the cytoplasm in the form of malate
[en] The trivalent cerium forms with tetraethylenepentaamine-heptaacetic acid (TPHA) a complex [CeIII]/[TPHA]=1/2, its stability constant, pK', at pH5 is equal to 14.14. The complex [CeIII]/[TPHA]=1/2 is found to be unstable, the instability increased as a function of pH and time and increased with the excess of [TPHA]. [TPHA] was found to reduce simultaneously tetravalent cerium. The solubilisation of cerium hydroxides by [TPHA] as a function of pH, concentration of [TPHA] and contact time between the hydroxides and the chelating agent is investigated
[fr]Le cerium trivalent forme un complexe [CeIII]/[TPHA]=1/2 de constante de stabilite a pH5, pK'=14,14; ce complexe presente une instabilite qui croit avec le pH et le temps, et decroit avec la concentration du chelatant. Le cerium tetravalent en presence de TPHA, est reduit instantanement a la valence III. Les differents parametres: pH, concentration du chelatant et temps, qui limitent la solubilisation de l'hydroxyde du cerium ont ete etudies
[en] The seeds of Butea parviflora were investigated for oil extraction and the oil was studied for complete physico-chemical properties. The fatty acid profile of the seed oil showed oleic acid (18:1) at 27.5%, linoleic acid (18:2) at 26.4%, palmitic acid (16:0) at 16.1% and behenic acid (22:0) at 14.1% as the major fatty acids. The physico-chemical characteristics of the seed oil were studied for parameters such as free fatty acids (0.71%), iodine value (76.2 g/100g), peroxide value (5.95 ppm), saponification value (177.32 mg KOH/g), unsaponifiable matter (0.82%), phosphorous content (197 ppm), triglyceride analysis, tocols, specific gravity and refractive index following standard procedures.
[es]Se ha estudiado la extracción de aceite de semillas de Butea parviflora así como las características físico-químicas completas del aceite. El perfil de ácidos grasos está compuesto de un 27,5% de ácido oleico (18:1), 26,4% de ácido linoleico (18:2), 16,1% de ácido palmítico (16:0) y 14.1% de behénico (22:0) como principales ácidos grasos. Se han estudiado las características físico-químicas del aceite de las semilla tales como los ácidos grasos libres (0,71%), índice de yodo (76,2 g/100 g), índice de peróxido (5,95 ppm), índice de saponificación (177,32 mg KOH/g), materia insaponificable (0,82%), contenido en fósforo (197 ppm), análisis de triglicéridos, gravedad específica e índice de refracción, siguiendo los protocolos recogidos en procedimientos estandarizados.