Reaction pathways and rate constants of gas-phase uranium and uranium oxide ions with O2 and H2O have been investigated using a quadrupole ion trap mass spectrometer (QIT-MS). A new reaction pathway is identified for the reaction between U2+ and H2O, which leads to the formation of UO+ via the intermediate UOH2+. Reaction rate constants are determined for several reactions by measuring the reac...

Reaction mechanisms for the initial stages of naphthalene oxidation at high temperatures (T ≥ 600 K) have been studied theoretically using density functional theory along with various exchange-correlation functionals, as well as the benchmark CBS-QB3 quantum chemical approach. These stages correspond to the removal of hydrogen atoms by hydroxyl radical and the formation thereby of 1- and 2-naph...

Ralstonia eutropha strain E2 (previously Alcaligenes sp.) is a phenol-degrading bacterium expressing phenol-oxygenating activity with a low Ks (the apparent half-saturation constant in Haldane's equation) and an extremely high KSI (the apparent inhibition constant). To identify the molecular basis for these novel cellular kinetic properties, a 9.5 kb DNA fragment that allowed Pseudomonas aerugi...

A kinetic model of the glutamate DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor/channel complex was used to test whether changes in the rate constants describing channel behavior could account for various features of long-term potentiation (LTP). Starting values for the kinetic parameters were set to satisfy experimental data (e.g., affinity, mean open time, mean bu...

An improved kinetic model for the Meinel bands of OH has been constructed from rate constants and Einstein A coefficients derived in recent laboratory experiments. Using a semiempirical parameterization of the state-to-state rate constants for OH(v) quenching by O2, the absolute OH(v) nightglow radiances are modeled to within the accuracies of the atmospheric constituent concentrations and the ...

Many organophosphorus compounds are irreversible inhibitors of acetylcholinesterase. The methods used in the literature to determine the inhibition kinetic constants usually involve either manual determination of the slope at various points along the inhibition progress curve or fitting polynomials to the curve. The present study investigates the use of non-linear-regression analysis to determi...

Thermodynamic studies of equilibrium chemical reactions linked with kinetic procedures are mostly impossible by traditional approaches. In this work, the new concept of generalized kinetic study of thermodynamic parameters is introduced for dynamic data. The examples of equilibria intertwined with kinetic chemical mechanisms include molecular charge transfer complex formation reactions, pH-depe...

A theoretical study of the kinetic and mechanism of intramoleccha cychcation of (1)-undeca-7,8-dien-2-yne was performed using MT methods at B3LYP and B3PW91 levels of theory using 6-311g, 6-311C.6-31 IGs*, 6-31I+G, 6-31 I4-SG and 6-3114H-Gs* basis seo. Equilibrium molecular geometries andharmonic vibrational frequencies of the reaccint, transition state and product wens calculated. Theconsidere...

Kinetic and thermodynamic studies reveal that the property of significantly enhanced catalytic activity with colloidal stability is attributed to an efficacious means of tuning enzyme-substrate association by varying with the rate constants in the presence of functionalized gold nanoparticles.

The kinetics of the transesterification of phosphatidylcholine (PC) with α-linolenic acid ethyl ester (ALAEE) catalyzed by immobilized lipase in hexane was studied. The reaction proceeded via a Ping-Ping Bi-Bi mechanism without inhibition by both the substrates at various concentrations tested. A reaction kinetic model was proposed with the experimental data. The kinetic constants of the model ...