The enthalpy changes for phosphorylating and nonphosphorylating mitochondrial oxidation of succinate by ferricyanide were studied by heatburst microcalorimetry. The enthalpy change observed with a nonphosphorylating system involving sonically disrupted mitochondria agreed with the calculated enthalpy change. The enthalpy changes for phosphorylating and uncoupled systems involving intact mitocho...

This study demonstrates that the modelling approach for the kinetic phenomenon of glass transition is effective to examine the relaxation. In the enthalpy relaxation of poly(cyanobiphenyl-yloxy) alkyl acrylate, the decrease in enthalpy was measured as a function of ageing time and ageing temperature. Obtained data was analysed at first with the activation energy spectrum (AES) model, and next, ...

Differential scanning calorimetry and Fourier-transform infrared spectroscopy have been used to characterize the thermal stability of bacteriorhodopsin (BR) cleaved within different loops connecting the helical rods. The results are compared to those of the native protein. We show that the denaturation temperature and enthalpy of BR cleaved at peptide bond 71-72 or 155-156 are lower than those ...

The time and temperature dependencies of the line area (M0) and position (M1) of band III at approximately 760 nm have been measured with Fourier-transform infrared spectroscopy in deoxymyoglobin (Mb) and continuously photolyzed carbon monoxide myoglobin (MbCO). Below 200 K, the area of band III in the photoproduct Mb* increases with time even on time scales of hours. This behavior indicates ch...

The solid state reactions and structural evolution in nanocrystalline FePt powders during mechanical ball milling at 77 K and subsequent annealing have been investigated. Above 310 °C the formation of L10 FePt is observed. As the milling time increases, the enthalpy evolved during the transformations is reduced, whereas the corresponding activation energy increases. For accelerating the orderin...

MgH(2) nanoparticles with a size of <3 nm were formed by direct hydrogenation of Bu(2)Mg inside the pores of a carbon scaffold. The activation energy for the dehydrogenation was lowered by 52 kJ mol(-1) compared to the bulk material, and a significantly reduced reaction enthalpy of 63.8 ± 0.5 kJ mol(-1) and entropy (117.2 ± 0.8 J mol(-1)) was found for the nanoconfined system.

The internal friction of high-purity NiAl single crystals was investigated utilizing a low-frequency subresonance torsion a p m . Above lOOOK the damping increases strongly up to Q-' =0.3 at 1400K. The activation enthalpy of this viscoelastic relaxation depends on the composition and shows the highest value (2.8eV) for stoichiometric NiAl. The results are discussed in terms of diffusionantrolle...

A combined kinetic and computational study on our tryptophan-based bifunctional thiourea catalyzed asymmetric Mannich reactions reveals an apparent negative activation enthalpy. The formation of the pre-transition state complex has been unambiguously confirmed and these observations provide an experimental support for the formation of multiple hydrogen bonding network between the substrates and...

BACKGROUND Heat stress evaluation and timely notification, especially using meteorological data is an important issue attracted attention in recent years. Therefore, this study aimed at answering the following research questions: 1) can enthalpy as a common environmental parameter reported by meteorological agencies be applied accurately for evaluation of thermal condition of outdoor settings, ...