Pump Probe Technique
Mostrando 13-20 de 20 artigos, teses e dissertações.
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13. Mechanism of the initial charge separation in bacterial photosynthetic reaction centers.
The initial electron transfer in reaction centers from Rhodobacter sphaeroides R26 was studied by a subpicosecond transient pump-probe technique. The measured kinetics at various wavelengths were analyzed and compared with several mechanisms for electron transfer. An unambiguous determination of the initial electron transfer mechanism in reaction centers can
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14. Membrane transport mechanisms probed by capacitance measurements with megahertz voltage clamp.
We have used capacitance measurements with a 1-microsecond voltage clamp technique to probe electrogenic ion-transporter interactions in giant excised membrane patches. The hydrophobic ion dipicrylamine was used to test model predictions for a simple charge-moving reaction. The voltage and frequency dependencies of the apparent dipicrylamine-induced capacita
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15. Ultrafast detection and control of molecular dynamics
Many elementary chemical and physical processes such as the breaking of a chemical bond or the vibrational motion of atoms within a molecule take place on a femtosecond (fs = 10−15 s) or picosecond (ps = 10−12 s) time scale. It is now possible to monitor these events as a function of time with temporal resolution well below 100 fs. This capability i
The National Academy of Sciences.
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16. Fluid transport across retinal pigment epithelium is inhibited by cyclic AMP.
Fluid transport across the retinal pigment epithelium (bullfrog) has been measured. These experiments were carried out by using a capacitance probe technique and a water-impermeable chamber that allowed the measurements to be made with an accuracy of 0.5-1.0 nl/min. With identical Ringer's solution on both sides of the epithelium, and in the absence of a hyd
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17. Resonance Raman studies of bathorhodopsin: Evidence for a protonated Schiff base linkage
A dual beam pump/probe technique has been used with a 585-nm probe wavelength to obtain maximal resonance enhancement of the Raman lines of bathorhodopsin in a photostationary steady-state mixture at -160°C. These studies show that bathorhodopsin has a protonated Schiff base vibration at 1657 cm-1 which shifts upon deuteration to 1625 cm-1. Within our exper
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18. Effects of Growth Irradiance and Nitrogen Limitation on Photosynthetic Energy Conversion in Photosystem II 1
Photosynthetic energy conversion was investigated in five species of marine unicellular algae, (Dunaliella tertiolecta, Thalassiosira pseudonana, T. weisflogii, Skeletorema costatum, Isochrysis galbana) representing three phylogenetic classes, which were grown under steady state conditions with either light or inorganic nitrogen as a limiting factor. Using a
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19. Comparative studies on the electrical properties of the H+ translocating ATPase and pyrophosphatase of the vacuolar-lysosomal compartment.
The electrical properties of the vacuolar-lysosomal H+ pumps were studied by direct measurement of the pump currents using the whole-cell configuration of the patch-clamp technique. Both pumps, the proton-translocating ATPase and pyrophosphatase, when activated by MgATP or inorganic Mg pyrophosphate (MgPP(i)), transport protons into the vacuole and polarize
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20. Picosecond kinetics of fluorescence and absorbance changes in photosystem II particles excited at low photon density
Oxygen-evolving photosystem II particles (from Synechococcus) with about 80 chlorophyll molecules per primary electron donor (P680) were used for a correlated study of picosecond kinetics of fluorescence and absorbance changes, detected by the single-photon-timing technique and by a pump-probe apparatus, respectively. Chlorophyll fluorescence decays were bie