H-transfer was studied in the complex kinetic cascade of dihydrofolate reductase. Intrinsic kinetic isotope effects, their temperature dependence, and other temperature-dependent parameters indicated H-tunneling, but no 1 degrees to 2 degrees coupled motion. The data also suggested environmentally coupled tunneling and commitment to catalysis on pre-steady-state isotope effects.

Kinetic resolution of 2-arylindolines (2,3-dihydroindoles) was achieved by treatment their N-tert-butoxycarbonyl (Boc) derivatives with n-butyllithium and sparteine in toluene at −78 °C followed electrophilic quench. The unreacted starting materials together the 2,2-disubstituted products could be isolated high enantiomer ratios. Variable temperature NMR spectroscopy showed that rate Boc rotati...

A new seawater Boussinesq system is introduced, and it is shown that this approximation to the equations of motion of a compressible binary solution has an energy conservation law that is a consistent approximation to the Bernoulli equation of the full system. The seawater Boussinesq approximation simplifies the mass conservation equation to $ u 5 0, employs the nonlinear equation of state of s...

We study the asymptotic behavior of kinetic free-transport equation enclosed in a regular domain, on which no symmetry assumption is made, with Cercignani–Lampis boundary condition. give first proof existence steady state case where temperature at wall varies, and derive optimal rate convergence toward it, L1 norm. The strategy an application deterministic version Harris’ subgeometric theorem, ...

objective(s): the quantitative calculation of release data is more facil when mathematics come to help. mathematically modeling could aid optimizing and amending the delivery systems design. aim of this study is to find out the isoniazid release kinetic. methods: in this work degradable temperature sensitive dextran-hydroxy ethyl methacrylate- poly-n-isopropyl acryl amide (dex-hema-pnipaam) nan...

Results of electro-thermo-elastic analysis of a functionally graded thick-walled spherical shell made of temperature dependent materials are presented in this article. All material properties are assumed temperature-dependent and also are graded along the thickness direction based on power function. Temperature dependency is accounted for all material properties including, thermal, mechanical a...

We present a critical view of the analysis of experimental island densities acquired as a function of temperature in terms of barriers and prefactors for tracer diffusion at surfaces. We investigate the achievable precision for methods ranging from simple application of scaling laws, via integration of mean-field rate equations within various approximations for the capture rates, to kinetic Mon...

Reaction furnace is the most important part of the Claus sulfur recovery unit and its performance has a significant impact on the process efficiency. Too many reactions happen in the furnace and their kinetics and mechanisms are not completely understood; therefore, modeling reaction furnace is difficult and several works have been carried out on in this regard so far. Equilibrium models are co...

Until now, all methods for temperature sensing in capillary electrophoresis (CE) relied on molecular probes with temperature-dependent spectral/optical properties. Here we introduce a nonspectroscopic approach to determining temperature in CE. It is based on measuring a temperature-dependent rate constant of complex dissociation by means of a kinetic CE method known as nonequilibrium capillary ...

The kinetic of Fischer-Tropsch synthesis over a co-precipitated Fe-Ce catalyst was investigated in a fixed bed micro reactor. Experimental conditions were varied as follow: reaction pressure 1-15bar, H¬¬¬2/CO feed ratio of 1-3 and space velocity of 3600-5400 h-1 at the temperature range of 270-310°C. 4 models according to the Langmuir-Hinshelwood-Hougen-Watson (LHHW) type rate equation were der...