The effect of temperature (0-22 degrees C) on the kinetics of Na channel conductance was determined in voltage-clamped rabbit and frog skeletal muscle fibers using the triple-Vaseline-gap technique. The Hodgkin-Huxley model was used to extract kinetic parameters; the time course of the conductance change during step depolarization followed m3h kinetics. Arrhenius plots of activation time consta...

Careful analysis of the Arrhenius plot of the Na+,Mg2+-ATPase (ATP pyrophosphohydrolase, EC 3.6.1.8) activity in Acholeplasma laidlawii B membranes of varying fatty acid composition has been combined with differential thermal analysis of the membrane lipid phase transitions to evaluate the effects of membrane lipid properties on the enzyme activity. Our results indicate that the enzyme is activ...

The present study is concerned with the kinetics and thermodynamic study of urease extracted from soybeans. The effect of pH, temperature, concentration of substrate and incubation time on the urease activity was examined. Maximum urease activity (86.79 ± 2.43 U/g) was obtained at 30 o C and pH 8.0 after 60 sec of incubation. Kinetics constants i.e. Km and Vmax were estimated by using Lineweave...

Triphenyl tetrazolium chloride (TTC) reduction by cucumber (Cucumis sativus L. cv Poinsett 76 and cv Ashley) leaf discs was used as a viability assay to examine the effect of temperature pretreatment on the tissue response to acute hyperthermia. Semi-logarithmic plots of TTC reduction as a function of incubation time at different temperatures from 40 to 60[deg]C resembled the heat survival curv...

It is becoming common practice to partition glass-forming liquids into two classes based on the dependence of the shear viscosity η on temperature T. In an Arrhenius plot, ln η vs 1/T, a strong liquid shows linear behavior whereas a fragile liquid exhibits an upward curvature [super-Arrhenius (SA) behavior], a situation customarily described by using the Vogel-Fulcher-Tammann law. Here we analy...

A model example for size effects on the dynamic susceptibility behavior is provided by the chain compound [{Dy(hfac)(3)NitPhIm(2)}Dy(hfac)(3)] (NitPhIm = 2-[4-(1-imidazole)phenyl]nitronyl nitroxide radical). The Arrhenius plot reveals two relaxation regimes attributed to SMM (Delta = 17.1 K and tau(0) = 17.5 x 10(-6) s) and SCM (Delta = 82.7 K and tau(0) = 8.8 x 10(-8) s) behaviors. The ferroma...

The effect of the growth temperature on the formation of uniform self-assembled Ge dots on Si ~001! substrates was studied. The ratio of pyramid dots to dome dots varies with the growth temperature from 500 to 700 °C. Temperature of 600 °C was optimum to form uniform self-assembled Ge dots, and is attributed to the enhanced diffusion kinetics. Highly uniform Ge dots with height deviation of 63%...

Experiments are described in which we used a mass spectrometer to monitor O(2) uptake of enclosed soil samples as a function of temperature. We found that an Arrhenius plot of the rate of O(2) uptake showed pronounced local maxima attributable to biological activity, whereas similar plots of rates obtained with abiotic soils yielded straight lines. This procedure thus provides a basis for disti...

In this paper we have investigated the temperature dependence of the charging effects in Metal-Insulator-Metal structures, aiming to obtain a better insight on the charging mechanism of RF-MEMS switch insulating layer. The accumulated charge kinetics have been monitored through the transient response of the depolarization current. The transient response is shown to follow rather a stretched exp...

The intramolecular (13)C kinetic isotope effects for the ring-opening of cyclopropylcarbinyl radical were determined over a broad temperature range. The observed isotope effects are unprecedentedly large, ranging from 1.062 at 80 degrees C to 1.163 at -100 degrees C. Semiclassical calculations employing canonical variational transition-state theory drastically underpredict the observed isotope ...