Rate constants for the etching of gallium arsenide by molecular iodine

1992 ◽  
Vol 10 (2) ◽  
pp. 668 ◽  
Author(s):  
Kin-Chung Wong
Keyword(s):  
Gallium Arsenide ◽  
Rate Constants ◽  
Molecular Iodine

Photolyse de l'iodure de vinyle pur et en solution dans le tétrachlorure de carbone. II. Rendements quantiques

1967 ◽  
Vol 45 (12) ◽  
pp. 1361-1367 ◽  
Author(s):  
Pierre C. Roberge ◽  
Jan A. Herman
Keyword(s):  
Rate Constants ◽  
Molecular Iodine ◽  
Reaction Scheme ◽  
Quantum Yields ◽  
Controlled Processes ◽  
Diffusion Controlled ◽  
Vinyl Radicals ◽  
Vinyl Iodide

The quantum yields of acetylene and molecular iodine from the photolysis of pure vinyl iodide are 0.22 and 0.07 respectively. The disproportionation/recombination ratio for vinyl radicals with iodine atoms in diffusion-controlled processes is 0.34, as established from the quantum yields. A reaction scheme is proposed and several ratios of rate constants are calculated.

Aqueous-gas phase partitioning and hydrolysis of organic iodides

2003 ◽  
Vol 81 (3) ◽  
pp. 230-243 ◽  
Author(s):  
G A Glowa ◽  
J C Wren
Keyword(s):  
Rate Constants ◽  
Partition Coefficients ◽  
Nuclear Reactor ◽  
Molecular Iodine ◽  
Molecular Structures ◽  
Hydrolysis Rate ◽  
Reactor Accident ◽  
Phase Partitioning ◽  
Temperature Dependences ◽  
Hydrolysis Of

The volatility and decomposition of organic iodides in a reactor containment building are important parameters to consider when assessing the potential consequences of a nuclear reactor accident. However, there are few experimental data available for the volatilities (often reported as partition coefficients) or few rate constants regarding the decomposition (via hydrolysis) of organic iodides. The partition coefficients and hydrolysis rate constants of eight organic iodides, having a range of molecular structures, have been measured in the current studies. This data, and data accumulated in the literature, have been reviewed and discussed to provide guidelines for appropriate organization of organic iodides for the purpose of modelling iodine behaviour under postulated nuclear reactor accident conditions. After assessment of the partition coefficients and their temperature dependences of many classes of organic compounds, it was found that organic iodides could be divided into two categories based upon their volatility relative to molecular iodine. Similarly, hydrolysis rates and their temperature dependences are assigned to the two categories of organic iodides.Key words: organic iodide, hydrolysis, partition coefficient, iodine behaviour model, nuclear reactor safety.

Inhibition in Purified Systems and in Human Plasma of Chimaeric Plasminogen Activators Consisting of the NH2-Terminal Region of Tissue-Type Plasminogen Activator and the COOH-Terminal Region of UrokinaseType Plasminogen Activator

1988 ◽  
Vol 60 (02) ◽  
pp. 247-250 ◽  
Author(s):  
H R Lijnen ◽  
L Nelles ◽  
B Van Hoef ◽  
F De Cock ◽  
D Collen
Keyword(s):  
Plasminogen Activator ◽  
Rate Constants ◽  
Plasminogen Activators ◽  
Second Order ◽  
Tissue Type ◽  
Single Chain ◽  
Chain Molecules ◽  
Order Rate ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator

SummaryRecombinant chimaeric molecules between tissue-type plasminogen activator (t-PA) and single chain urokinase-type plasminogen activator (scu-PA) or two chain urokinase-type plasminogen activator (tcu-PA) have intact enzymatic properties of scu-PA or tcu-PA towards natural and synthetic substrates (Nelles et al., J Biol Chem 1987; 262: 10855-10862). In the present study, we have compared the reactivity with inhibitors of both the single chain and two chain variants of recombinant u-PA and two recombinant chimaeric molecules between t-PA and scu-PA (t-PA/u-PA-s: amino acids 1-263 of t-PA and 144-411 of u-PA; t-PA/u-PA-e: amino acids 1-274 of t-PA and 138-411 of u-PA). Incubation with human plasma in the absence of a fibrin clot for 3 h at 37° C at equipotent concentrations (50% clot lysis in 2 h), resulted in significant fibrinogen breakdown (to about 40% of the normal value) for all two chain molecules, but not for their single chain counterparts. Preincubation of the plasminogen activators with plasma for 3 h at 37° C, resulted in complete inhibition of the fibrinolytic potency of the two chain molecules but did not alter the potency of the single chain molecules. Inhibition of the two chain molecules occurred with a t½ of approximately 45 min. The two chain variants were inhibited by the synthetic urokinase inhibitor Glu-Gly-Arg-CH2CCl with apparent second-order rate constants of 8,000-10,000 M−1s−1, by purified α2-antiplasmin with second-order rate constants of about 300 M−1s−1, and by plasminogen activator inhibitor-1 (PAI-1) with second-order rate constants of approximately 2 × 107 M−1s−1.It is concluded that the reactivity of single chain and two chain forms of t-PA/u-PA chimaers with inhibitors is very similar to that of the single and two chain forms of intact u-PA.

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