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941.
Fabiane Carvalho Ballotin Mayra Nascimento Sara Silveira Vieira Alexandre Carvalho Bertoli Ottávio Carmignano Ana Paula de Carvalho Teixeira Rochel Montero Lago 《矿物冶金与材料学报》2020,27(1):46-54
In this work, different magnesium silicate mineral samples based on antigorite, lizardite, chrysotile (which have the same general formula Mg3Si2O5(OH)4), and talc (Mg3Si4O10(OH)2) were reacted with KOH to prepare catalysts for biodiesel production. Simple impregnation with 20wt% K and treatment at 700–900°C led to a solid-state reaction to mainly form the K2MgSiO4 phase in all samples. These results indicate that the K ion can diffuse into the different Mg silicate structures and textures, likely through intercalation in the interlayer space of the different mineral samples followed by dehydroxylation and K2MgSiO4 formation. All the materials showed catalytic activity for the transesterification of soybean oil (1:6 of oil : methanol molar ratio, 5wt% of catalyst, 60°C). However, the best results were obtained for the antigorite and chrysotile precursors, which are discussed in terms of mineral structure and the more efficient formation of the active phase K2MgSiO4. 相似文献
942.
Summary In rat intestine, the glutathione level was increased, glutathione peroxidase activity decreased and glutathione-S-transferase unchanged by vitamin A deficiency. 相似文献
943.
In rat intestine, the glutathione level was increased, glutathione peroxidase activity decreased and glutathione-S-transferase unchanged by vitamin A deficiency. 相似文献
944.
Cloning of a gene that is rearranged in patients with choroideraemia 总被引:18,自引:0,他引:18
Choroideraemia (tapetochoroidal dystrophy, TCD), a common form of X-linked blindness, is characterized by progressive dystrophy of the choroid, retinal pigment epithelium and retina. Previous studies have assigned the TCD gene to a small segment of the Xq21 band. By making use of reverse genetics strategies we have isolated eight overlapping complementary DNA clones from the same chromosomal region. The corresponding gene is expressed in retina, choroid and retinal pigment epithelium. The cDNAs encompass an open reading frame of 948 base pairs that is structurally altered in eight TCD patients with deletions, and in a female patient with a balanced translocation involving Xq21. These findings provide strong evidence that we have cloned the gene underlying choroideraemia. Elucidation of its function should provide new insights into the molecular mechanisms responsible for this disorder and other hereditary retinopathies. 相似文献
945.
C-banding and mithramycin staining were used to characterize the karyotypes of 10 specimens of the African reed frog Hyperolius viridiflavus ommatostictus from Tanzania. The diploid chromosome number is 2n = 24. Although no heteromorphic sex chromosomes were present in the mitotic karyotypes, in many diakineses of male meiosis one or two bivalents exhibited an end-to-end arrangement. In the laboratory 7 out of 24 females changed sex spontaneously. This indicates that an XY/XX system of sex determination operates in H. viridiflavus ommatostictus. 相似文献
946.
947.
Zusammenfassung Häftlinge verschiedener Herkunft und Lebensweise, unter gleichen Umständen längere Zeit im Gefängnis, wurden in zwei Gruppen geteilt: 36 Männer mit Serumcholesterolwerten niedriger als 200 mg%, und 101 Männer mit Werten von 200 mg% und mehr. Die Daten von Alter, Länge, Gewicht, Armumfang, Subkutanfett, Brustumfang, EKG, Qualität und Quantität der Ernährung und Energieverbrauch bewiesen, dass Männer mit niedrigen Cholesterolwerten signifikant aktiver, weniger fett und jünger waren als Männer mit höheren Cholesterolwerten. 相似文献
948.
The neurohypophysial hormone vasopressin exerts antidiuretic, vasopressor and behavioural effects (for example, facilitation of memory processes). Vasopressin may alter animal behaviour via direct effect on brain processes. Recently, however, it has been suggested that vasopressin acts mainly at peripheral receptor systems and influences behavioural mechanisms by altering visceral afferent signals. We now present data showing that (1) central administration of [Arg8]vasopressin (AVP) and more potently [pGlu, Cyt]AVP(4-8), the desglycinamide derivative of a peptide generated from AVP by brain synaptic membranes, produce the behavioural effect (promotion of passive avoidance behaviour) without the pressor effect; (2) central administration of a vasopressor antagonist blocks the behavioural but not the pressor effect of systemically administered AVP; and (3) [pGlu, Cyt]AVP(4-8) induces the behavioural effect in the absence of the pressor effect. The results indicate that AVP and related peptides affect passive avoidance behaviour by a direct central action and that the structural requirement for activation of central vasopressin receptors differs from that of the peripheral cardiovascular receptors, although both can be blocked by the same vasopressor antagonist. 相似文献
949.
L. Bernardi G. Bosisio F. Chillemi G. de Caro R. de Castiglione V. Erspamer A. Glaesser O. Goffredo 《Cellular and molecular life sciences : CMLS》1965,21(12):695-697
Riassunto Vengono descritte le proprietà di una serie di peptidi sintetici affini per struttura ed attività all'eledoisina
Part IV, for part III see3. 相似文献
Part IV, for part III see3. 相似文献
950.