Equilibration Time
Mostrando 13-24 de 84 artigos, teses e dissertações.
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13. Determination of aqueous solubility by heating and equilibration: A technical note
A modified shake-flask solubility method, where the equilibration time was shortened through heating, was used to determine the solubility of 48 different drugs and pharmaceutical excipients in pure water at room temperature. The heating process accelerates dissolution of the solid compound and frequently results in supersaturated solution. Seeding with the
Springer-Verlag.
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14. Vibrational equilibration in absorption difference spectra of chlorophyll a.
We describe Franck-Condon simulations of vibrational cooling effects on absorption difference spectra in chlorophyll a (Chl a). The relative contributions of vibrational equilibration in the electronic ground and excited states depend on the pump and probe wavelengths. For Franck-Condon-active vibrational modes exhibiting small Huang-Rhys factors (S < 0.1, c
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15. Electron transfer between hemes in mammalian cytochrome c oxidase
Fast intraprotein electron transfer reactions associated with enzymatic catalysis are often difficult to synchronize and therefore to monitor directly in non-light-driven systems. However, in the mitochondrial respiratory enzyme cytochrome oxidase aa3, the kinetics of the final electron transfer step into the active site can be determined: reverse electron f
National Academy of Sciences.
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16. Water Flow in Beta vulgaris Storage Tissue 1
The relative magnitudes of the hydraulic resistances, water capacities, and water potential equilibration time constants for the single cell, for the apoplast, and for the symplast in higher plant tissue are assessed. Swelling of beetroot (Beta vulgaris, var. `Detroit Red') storage tissue sections in pure water is measured using a displacement transducer. Th
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17. Dilution kinetics of H(2)18O for the measurement of total body water in preterm babies in the first week after birth.
The aim of this study was to determine the kinetics of H(2)18O equilibration and elimination in preterm babies for the estimation of total body water. Thirteen, clinically stable, preterm babies of less than 32 weeks' gestation were studied in the first week after birth. Blood and urine samples were obtained for baseline measurement of 18O:16O ratio and 1 ml
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18. Direct observation of sub-picosecond equilibration of excitation energy in the light-harvesting antenna of Rhodospirillum rubrum.
Excitation energy transfer in the light-harvesting antenna of Rhodospirillum rubrum was studied at room temperature using sub-picosecond transient absorption measurements. Upon excitation of Rs. rubrum membranes with a 200 fs, 600 nm laser flash in the Qx transition of the bacteriochlorophyll-a (BChl-a) absorption, the induced transient absorption changes in
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19. Separation of Treponema pallidum from Tissue Debris Through Continuous-Particle Electrophoresis
Treponema pallidum can only be cultured in living animal tissue, such as rabbit testes. However, the extract of these organisms from the testicular material leaves the T. pallidum contaminated with tissue debris. This paper describes the separation of T. pallidum from the debris by continuous-particle electrophoresis. The importance of equilibration time bef
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20. Induced Changes in Permeability of Plant Cell Membranes to Water
The half-time for THO equilibration was three times longer for a living carrot (Daucus carota L.) cylinder than for a dead one. Furthermore, the energy of activation of THO flux was more than twice as high for the living cylinder. Passage through living membranes thus constitutes a rate-limiting step for THO flux in carrot tissue.
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21. Water-relation Parameters of Individual Mesophyll Cells of the Crassulacean Acid Metabolism Plant Kalanchoë daigremontiana1
Water-relation parameters of leaf mesophyll cells of the CAM plant Kalanchoë daigremontiana have been determined directly in cells of tissue slices using the pressure-probe technique. Turgor pressures measured in cells of the second to fourth layer from the cut surface showed an average of 1.82 ± 0.62 bar (mean ± sd; n = 157 cells). This was lower than ex
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22. Equilibration of the terrestrial water, nitrogen, and carbon cycles
Recent advances in biologically based ecosystem models of the coupled terrestrial, hydrological, carbon, and nutrient cycles have provided new perspectives on the terrestrial biosphere’s behavior globally, over a range of time scales. We used the terrestrial ecosystem model Century to examine relationships between carbon, nitrogen, and water dynamics.
The National Academy of Sciences of the USA.
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23. Yellow Fever Virus. II. Factors Affecting the Plaque Neutralization Test
In studies on the factors and conditions influencing the yellow fever (YF) virus plaque neutralization test, 60 min was found to be the minimal time necessary for equilibration of the virus-antibody complex at 23 and 37 C. Maximal virus titers in the diluent controls and the pre- and postinoculation serum-containing mixtures occurred by the 60-min adsorption
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24. Direct measurement of chlorine penetration into biofilms during disinfection.
Transient chlorine concentration profiles were measured in biofilms during disinfection by use of a microelectrode developed for this investigation. The electrode had a tip diameter of ca. 10 microm and was sensitive to chlorine in the micromolar range. The biofilms contained Pseudomonas aeruginosa and Klebsiella pneumoniae. Chlorine concentrations measured