Adsorbed molecules are involved in many reactions on solid surface that are of great technological importance. As such, there has been tremendous effort worldwide to learn how to predict reaction rates and equilibrium constants for reactions involving adsorbed molecules. Theoretical calculation of both the rate and equilibrium constants for such reactions requires knowing the entropy and enthal...

Curiously, H2 desorption from Si~100!-231 follows approximately first-order kinetics rather than the expected second-order kinetics, arousing interest about the mechanism involved in the desorption process. We investigate the energetics and rate constants of three proposed mechanisms for H2 desorption from Si~100!231, namely, the prepairing mechanism, the isomerization mechanism, and the isolat...

Depending on the nucleotide sequence, the temperature, and other conditions, RNA hairpin-folding kinetics can be very complex. The complexity with a wide range of cooperative and noncooperative kinetic behaviors arises from the interplay between the formation of the loops, the disruption of the misfolded states, and the formation of the rate-limiting base stacks. With a rate constant model and ...

The standard mathematical model for stepwise "slow-binding" enzyme inhibition (E+Iright harpoon over left harpoonEIright harpoon over left harpoonEI( *)) assumes that the initial enzyme-inhibitor complex EI is always at equilibrium with the free component species E and I. This assumption implies that the dissociation rate constant (EI-->E+I) is infinitely higher than the isomerization rate cons...

Short liquid crystalline polymers in a nematic environment are very unlikely to cyclise. Hairpins, abrupt chain folds, favour cyclisation. As a result the cyclisation rate constant exhibits a maximum as a function of chain length. The maximum corresponds to a new object, a "ringlet". The rate constant also depends exponentially on temperature. This suggests excimer fluorescence as a probe of co...

Soil spiked with diesel oil was mixed with biowaste (vegetable, fruit and garden waste) at a 1:10 ratio (fresh weight) and composted in a monitored composting bin system for 12 weeks. Pure biowaste was composted in parallel. In order to discern the temperature effect from the additional biowaste effect on diesel degradation, one recipient with contaminated soil was hold at room temperature, whi...

The kinetics of thermal denaturation of a biliprotein, C-phycocyanin (C-PC) isolated from Spirulina platensis were studied at different pH values, ranging from 4.0 to 8.0. The denaturation of C-PC follows the first order kinetics and rate constant at pH 5.0 and temperature 55 degrees C is found to be 4.37 x 10(-5) s(-1), which increases to 5.46 x 10(-1) s(-1) at pH 7.0. The denaturation rate is...

Evolution of the kinetic potential of enzyme reactions is discussed. Quantitative assessment of the evolution of enzyme action has usually focused on optimization of the parametric ratio kcat./Km, which is the apparent second-order rate constant for the reaction of free substrate with free enzyme to give product. We propose that the general form kcat.[E]T/Km (where [E]T is total enzyme concentr...

Single-molecule force-clamp spectroscopy has become a powerful tool for studying protein folding/unfolding, bond rupture, and enzymatic reactions. Different methods have been developed to analyze force-clamp spectroscopy data on polyproteins to obtain kinetic parameters characterizing the mechanical unfolding of proteins, which are often modeled as a two-state process (a Poisson process). Howev...