Electric Driving
Mostrando 13-21 de 21 artigos, teses e dissertações.
-
13. A computer program allows the separation of a wide range of chromosome sizes by pulsed field gel electrophoresis.
The introduction of Pulsed Field Gel Electrophoresis techniques, which allow the separation of DNA molecules of molecular weights as high as chromosomes of lower eukaryotes, has given a powerful tool to geneticists. The resolution expected from these techniques is dependent on numerous parameters, among them pulse time and field strength. A given set of thes
-
14. Dielectric spectroscopy as a sensor of membrane headgroup mobility and hydration.
Dielectric spectroscopy is based on the response of the permanent dipoles to a driving electric field. The phospholipid membrane systems of dimyristoylphosphatidylcholine and dioleoylphosphatidylcholine can be prepared as samples of multilamellar liposomes with a well known amount of interlamellar water. For optimal resolution in dielectric spectroscopy one
-
15. A simple light-driven transmembrane proton pump.
Light-induced lipophilic porphyrin/aqueous acceptor charge separation across a single lipid-water interface can pump protons across the lipid bilayer when the hydrophobic weak acids, carbonylcyanide m-chlorophenylhydrazone and its p-trifluoromethoxyphenyl analogue, are present. These compounds act as proton carriers across lipid bilayers. In their symmetric
-
16. Multiple Paths for Nonphysiological Transport of K+ in Escherichia coli
Mutants of Escherichia coli lacking all of the known saturable K+ transport systems, “triple mutants,” require elevated K+ concentrations for growth. K+ transport activity in such mutants, called TrkF activity, has low substrate specificity and a low rate that increases with increasing external pH. Attempts to isolate mutants requiring even higher concen
American Society for Microbiology.
-
17. A quantitative assessment of models for voltage-dependent gating of ion channels
Voltage-gated ion channels open and close, or “gate,” in response to changes in membrane potential. The electric field across the membrane–protein complex exerts forces on charged residues driving the channel into different functional conformations as the membrane potential changes. To act with the greatest sensitivity, charged residues must be positio
National Academy of Sciences.
-
18. Dynamics of the B–A transition of DNA double helices
Although the transition from the B-DNA double helix to the A-form is essential for biological function, as shown by the existence of the A-form in many protein–DNA complexes, the dynamics of this transition has not been resolved yet. According to molecular dynamics simulations the transition is expected in the time range of a few nanoseconds. The B–A tra
Oxford University Press.
-
19. INTRACORPOREAL HEAT DISSIPATION FROM A RADIOISOTOPE-POWERED ARTIFICIAL HEART
The feasibility of radioisotope-fueled circulatory support systems depends on the ability of the body to dissipate the reject heat from the power source driving the blood pump as well as to tolerate chronic intracorporeal radiation. Our studies have focused on the use of the circulating blood as a heat sink. Initial in vivo heat transfer studies utilized str
-
20. Retinal has a highly dipolar vertically excited singlet state: implications for vision.
We have measured the effect of an intense electric field on the absorption spectrum of solutions of all-trans retinal, its unprotonated Schiff base with n-butylamine, and the Cl- salt of this protonated Schiff base. The field-induced change in extinction coefficient as a function of wavelength was analyzed to determine the ground-state dipole moment (mug), t
-
21. Dielectric spectroscopy of single human erythrocytes at physiological ionic strength: dispersion of the cytoplasm.
Usually dielectrophoretic and electrorotation measurements are carried out at low ionic strength to reduce electrolysis and heat production. Such problems are minimized in microelectrode chambers. In a planar ultramicroelectrode chamber fabricated by semiconductor technology, we were able to measure the dielectric properties of human red blood cells in the f