Hydration Mechanism
Mostrando 13-24 de 58 artigos, teses e dissertações.
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13. Time-dependent behavior of sulphatic rocks of the anhydrite and gypsum / Comportamento dependente do tempo de rochas sulfáticas de anidrita e gipso
The purpose of this thesis is to contribute for the knowledge of time-dependent behavior of sulfatic rocks of anhydrite and gypsum. Emphasis is given to provide straightforward arguments about physical mechanisms responsible for creep observed in some underground excavations in those rocks in Europe. Explanation for this phenomena is not clear yet and studie
Publicado em: 2005
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14. THE INFLUENCE OF GLOMERULAR FILTRATION RATE, SOLUTE EXCRETION AND HYDRATION ON THE CONCENTRATING MECHANISM OF THE EXPERIMENTALLY DISEASED KIDNEY IN THE DOG *
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15. Carbon Dioxide Hydration Activity of Carbonic Anhydrase: Kinetics of Alkylated Anhydrases B and C from Humans*
A stop-flow kinetic study was performed on the carbon dioxide hydration activity of the human carbonic anhydrase B isoenzyme carboxymethylated at its histidine200, and of the human C isoenzyme carboxyketoethylated at its histidine63. The Michaelis-Menten parameters determined between pH 5.6 and 8.7 showed striking differences between the native and the alkyl
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16. The Hydration of Sodium Ions Crossing the Nerve Membrane
The sodium channel of the excitability mechanism in nerve membranes is about as permeable to hydroxylamine and hydrazine cations as it is to sodium ions. It is impermeable to methylamine cations. This selectivity is explained by supposing that an oxygen group in the channel must receive a hydrogen bond from the permeating cation at the same time as the catio
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17. Dielectric and conductivity studies of the hydration mechanisms in plant seeds.
The hydration mechanism of various plant seeds has been investigated by a) sorption-desorption isotherms, b) ac-dielectric spectroscopy in the 10 Hz to 1 GHz frequency range and the -80 to + 40 degrees C temperature range, and c) thermally stimulated depolarization current techniques in the -170 to + 23 degrees C temperature range. Seeds of different chemica
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18. Binding of a possible transition state analogue to the active site of carboxypeptidase A.
The mode of binding of the competitive inhibitor 2-benzyl-3-formylpropanoic acid to the active site of carboxypeptidase A has been studied by x-ray diffraction methods to a resolution of 1.7 A. The actual species bound to the enzyme was determined to be the gem-diol resulting from covalent hydration at the aldehyde carbonyl. Details relating to the process o
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19. Relaxation Study of Complex Formation between Monovalent Cations and Cyclic Polyethers
Equilibrium quotients for the 1:1 complexes of dibenzo-30-crown-10 with Na+, K+, Rb+, Cs+, NH4+, and T1+ in methanol solution have been determined spectrophotometrically. The observed selectivity pattern is discussed in terms of the hydration energy of the cations and the cation-ligand binding energy. The rate of complex formation is diffusion-controlled. Re
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20. Two-dimensional protonic percolation on lightly hydrated purple membrane
The capacitance and dielectric loss factor were measured for a sample of purple membrane of Halobacterium halobium as a function of hydration level (0.017 to >0.2 g of water/g of membrane) and frequency (10 kHz to 10 MHz). The capacitance and the derived conductivity show explosive growth above a threshold hydration level, hc ≈ 0.0456. The conductivity sho
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21. Stereospecific Enzymes in the Degradation of Aromatic Compounds by Pseudomonas putida
Two reactions in the catabolism of catechol by meta-fission, namely, hydration of 2-oxopent-4-enoate (vinylpyruvate) and aldol fission of the product, are catalyzed by stereospecific enzymes. The absolute configuration of this hydration product was shown to be l(S)-4-hydroxy-2-oxopentanoate. Vinylpyruvate hydratase, purified almost to homogeneity, had a mole
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22. Erythrocyte-neutrophil interactions: formation of leukotriene B4 by transcellular biosynthesis.
Studies on the mechanism of leukotriene B4 biosynthesis in suspensions composed of neutrophils plus erythrocytes indicate that human erythrocytes convert neutrophil-derived leukotriene A4 into leukotriene B4. Leukotriene B4 formation by neutrophils in the presence of erythrocytes exceeded that from corresponding suspensions of neutrophils alone. The increase
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23. Tamoxifen blocks chloride channels. A possible mechanism for cataract formation.
Tamoxifen is an antiestrogen frequently used in the treatment of breast cancer and is currently being assessed as a prophylactic for those at high risk of developing tumors. We have found that tamoxifen and its derivatives are high-affinity blockers of specific chloride channels. This blockade appears to be independent of the interaction of tamoxifen with th
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24. Regulation of trehalose metabolism by Streptomyces griseus spores.
Spores of Streptomyces griseus contain trehalose and trehalase, but trehalose is not readily hydrolyzed until spore germination is initiated. Trehalase in crude extracts of spores, germinated spores, and mycelia of S. griseus had a pH optimum of approximately 6.2, had a Km value for trehalose of approximately 11 mM, and was most active in buffers having ioni