Temperature dependence changes in the physical and chemical properties of ZnO detected by powder diffractometry

Reversible changes in temperature dependence of electric conductivity of hydrogenated amorphous silicon caused by proton irradiation

The scattering of non-equilibrium phonons in Al 2O 3 nanoceramics

Inherited erythromelalgia (IEM), caused by mutations in Nav1.7 channel is characterized by episodic neuropathic pain triggered especially by warm temperature. However, the mechanism underlying the temperature–dependent episodic attacks of IEM remains elusive. We investigated the electrophysiological effect of temperature changes on Nav1.7 channels with three different mutations, p.I136V, p. I848T, and p.V1316A, both in vitro and in vivo. In vitro biophysical studies of the mutant channels show consistent temperature-dependent enhancement of the relative resurgent currents if normalized to the transient currents, as well as temperature-dependent changes in the time to peak and the kinetics of decay of the resurgent currents, but no congruent temperature–dependent changes in steady–state parameters such as shift of activation/inactivation curves and changes of the absolute size of the window or resurgent currents. In vivo nerve excitability tests (NET) in IEM patients reveal the essentially normal indices of NET at a single stimulus. However, there are evident abnormalities if assessed with preconditioning pulses, such as the decrease of threshold elevation in hyperpolarizing threshold electrotonus (50–100 ms), the increase of inward rectification in current–voltage curve, and the increase of refractoriness at the interpulse interval of 2–6 ms in recovery cycle, probably also implicating derangements in temperature dependence of inactivation and of recovery from inactivation in the mutant channels. The pathogenesis of heat–enhanced pain in IEM could be attributed to deranged temperature dependence of Nav1.7 channels responsible for the genesis of resurgent currents.

Temperature Dependence and Thermodynamics of Klenow Polymerase Binding to Primed-Template DNA

Measurements of sharp diffraction peaks as a function of temperature are routinely used to obtain precise linear expansion coefficients of crystalline solids. In this case, the relation between temperature dependent changes in peak position in momentum transfer (q1) and volume expansion is straightforward (Ehrenfest's relation: q1 = K(2π/d), where K is a constant and d is the interatomic spacing) and the data obtained are usually in close agreement with more direct measurements. With high intensity synchrotron x-ray and spallation neutron sources, it is also possible to accurately measure the positions of the much broader peaks for liquids and glasses. This has led to a debate on whether linear expansion coefficients derived from these data are an accurate representation of the volume expansion coefficients. We present here volume thermal expansion and x-ray diffraction data for a large number of glass-forming alloy liquids acquired in a containerless environment using the beamline electrostatic levitation technique. The data show a large difference in the values obtained from the two different techniques. Moreover, the position of the first peak (q1) in the scattered intensity in the structure factor (S(q)) and the atomic volume v for all liquids follow a simple relationship, v∝(q1)−ε. The exponent, ε = 2.28 (±0.11), is much different from the expected value of 3 from Ehrenfest's relation and shows no temperature dependence over the temperature range of the data collected.

On the basis of data obtained by the incomplete fusion reactions 7Li(43A MeV)+232Th and 14N(34A MeV)+197Au, the energy dependence of the variance (σ M 2 ) of the fragment mass in fission of highly heated nuclei has been investigated for total excitation energies E tot * ranging from 50 up to 350 MeV. The dependence σ M 2 E tot * shows some unexpected features when E tot * exceeds a value of about 70 MeV. After this value, the steady increase of σ M 2 expected from its temperature dependence changes to some kind of plateau between 100 and 200 MeV. Further on, at E tot * in excess of about 250 MeV, the variance is found to increase again sharply. In order to analyze this behavior quantitatively, a dynamical stochastic model has been developed. The model employs the one-body dissipation mechanism and describes the decay of highly excited and rotating nuclei by fission and light-particle evaporation. It satisfactorily explains the measured prior-to-scission neutron multiplicities and the experimental mass variances up to E tot * ≅250 MeV, but the stochastic treatment does not reveal any increase in σ M 2 at higher excitation energies in contradiction with the data.

Temperature dependence of cytochrome c-induced phospholipid oxidation in liposomes

The effect of thermal acclimation on the electrocardiogram of goldfish

Reconstituted whole milk was heated using pilot-scale heating equipment. Kinetic and thermodynamic parameters for the irreversible denaturation of β-lactoglobulins A and B and α-lactalbumin were determined. α-Lactalbumin denaturation was first order, whereas both β-lactoglobulin variants had a reaction order of 1.5. Arrhenius plots for all three proteins showed an abrupt change in temperature dependence. In the low-temperature range, the thermodynamic parameters were ascribed to typical denaturation processes in which the unfolding of the protein tertiary structure is the rate-determining step. At higher temperatures, these parameters were in the range expected for typical condensation reactions, suggesting that aggregation processes may be rate-determining in this temperature range. The rate constants for β-lactoglobulin denaturation were independent of the initial protein concentration at all temperatures. For α-lactalbumin at temperatures below 85 °C the rate constants may have been dependent on the initial α-lactalbumin concentration as higher rate constants were observed with decreasing protein concentrations. Keywords: Whey protein; denaturation; whole milk; reconstituted milk

ABSTRACTThe effects of excitation rate and temperature on the kinetics and steady-state behavior of metastable defect formation in hydrogenated amorphous silicon (a-Si:H) have been studied. The dependences on temperature of the lifetime, τ, and stretching parameter, β, from a stretched exponential description of the kinetics were measured for one sample. We do not see a linear dependence of β on temperature over die entire temperature range studied (270K–370K), and τ increases monotonically with decreasing temperature. Steady-state results show defect density to be dependent on bodi temperature and excitation rate over the ranges measured (from 395K to 470K and from 6 × 1020 to 2 × 1022 s-l cm-3). The gradual change in temperature dependence is explained by a distribution of barrier heights between the ground and metastable states.

We use the dynamical mean field method to study the high-temperature resistivity of electrons strongly coupled to phonons. The results reproduce the qualitative behavior of the temperature and disorder dependence of the resistivity of ``A-15'' materials which is normally described in terms of saturation, but imply that the resistivity does not saturate. Rather, a change in temperature dependence occurs when the scattering becomes strong enough to cause a breakdown of the Migdal approximation.

Temperature dependence of multichannel gain flatness and noise figure (NF) was compared for different pump wavelengths of 1.48 and 0.98 /spl mu/m on silica-based erbium-doped fiber amplifiers (EDFAs) through measurement-based numerical simulation. Owing to its temperature sensitive pump emission cross section, the 1.48-/spl mu/m pumping showed greater temperature sensitivity (maximum 0.75-dB gain flatness distortion with 0.57-dB average gain level shift, 0.3-dB NF variation for 25/spl deg/C change) than the 0.98 /spl mu/m pumping (maximum 0.5-dB gain flatness distortion with 0.015-dB average gain level shift, 0.05-dB NF variation for 25/spl deg/C change). However, it was also found that distortion ripple spectra mainly coming from the changes of signal cross sections and asymmetric gain temperature dependence necessitate compensation techniques in the EDFA link, irrespective of pump wavelength.

Results of electrical conductivity and thermopower measurement on [CH(FeCl4)y]x are presented, where y covers the full doping range. The semiconductor-metal transition is evident and leads to a qualitative change in temperature dependence of the conductivity and thermopower. The analysis of the metallic thermopower data indicates the Kondo-like effect originated from the coupling between the (CH)X chain and the dopant located near the chain. As a consistent interpretation of our data, we propose a mechanism of the semiconductor-metal transition in doped (CH)X; the one dimensional intersoliton electron tunneling model.

Recently the change in temperature dependence of conductivity observed in polymer memory device prepared from polythiophene, has been attributed to a field-induced transition from a charge-injection-limited current to a trap controlled current. Under a high electrical field, the conductivity becomes independent on temperature and depends exponentially on the inverse of the applied field. In this paper we present a theoretical interpretation of this behavior in the framework of hopping mechanism, where the physical feature is the field effect on the tunneling probability.

Magnetic properties of graphene nanostructures functionalized with aromatic radicals were investigated by electron spin resonance (ESR) and superconducting quantum interference device (SQUID) techniques. Three types of functionalized graphene samples were investigated (functionalization was performed by 4-bromoaniline, 4-nitroaniline, or 4-chloroaniline). According to SQUID measurements, in case of functionalization by nitroaniline, sharp change in temperature dependence of magnetic susceptibility was observed near 120 K. Such behavior was explained as antiferromagnetic ordering. The same but more extended effect was observed in ESR measurements below 160 K. In the ESR measurements, only one resonance line with g-factor equal to 2.003 was observed. Based on the temperature dependencies of spin concentration and resonance position and intensity, the effect was explained as antiferromagnetic ordering along the extended defects on the basal planes of the graphene.