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K U Ingold - One of the best experts on this subject based on the ideXlab platform.
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laser flash photolysis studies on the first superoxide thermal source first direct measurements of the rates of solvent assisted 1 2 hydrogen atom shifts and a proposed new mechanism for this unusual rearrangement1
Journal of the American Chemical Society, 2000Co-Authors: Klara G Konya, Thomas Paul, Shuqiong Lin, And Janusz Lusztyk, K U IngoldAbstract:The thermal decomposition of bis(4-carboxybenzyl)hyponitrite (SOTS-1) in Aerated Water under physiological conditions has previously been shown to give the superoxide radical anion in a yield of 40 mol % (Ingold, K. U.; et al. J. Am. Chem. Soc. 1997, 119, 12364). The absolute kinetics of the elementary reactions involved in the cascade of events leading from the first-formed Water-soluble benzyloxyl radical to superoxide have been determined by laser flash photolysis. On the basis of these kinetics it is concluded that SOTS-1 will be suitable for studies of superoxide-induced oxidative stress in most biological systems. A Water-assisted 1,2-H shift converting benzyloxyl into the benzyl ketyl radical is an important step in the above reaction cascade. The kinetics of the 1,2-H shift assisted by H2O, D2O, and a number of nucleophilic alcohols have been measured for the first time. These data have led to a proposed new mechanism involving the initial formation of a ketyl radical anion and an oxonium cation w...
H Sabik - One of the best experts on this subject based on the ideXlab platform.
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evidence of coprostanol estrogenicity to the freshWater mussel elliptio complanata
Environmental Pollution, 2001Co-Authors: F Gagne, C Blaise, B Lachance, G I Sunahara, H SabikAbstract:Coprostanol (5β(H)-cholestan-3βol) is a reduced metabolite of cholesterol produced by micro-organisms found in the intestinal tract of mammals. This substance abounds in urban effluents and is accumulated by organisms living in the vicinity of municipal effluent outfalls. In an earlier study, freshWater mussels exposed to contaminated river Water for 62 days accumulated large quantities of coprostanol (Cop) in their soft tissues (16 μg/g dry wt.). Moreover, these mussels were found to have elevated levels of vitellin in their hemolymphs, suggesting estrogenic effects. Although municipal wasteWaters are known to contain other estrogenic compounds capable of inducing Vn synthesis in mussels, the estrogenic potential of coprostanol was singled out for examination. To this end, mussels were first injected with concentrations of coprostanol via the abductor muscle route, and allowed to stand in Aerated Water for 72 h at 15°C. The levels of Vn in mussel hemolymph were assayed using the organic alkali-labile phosphate method. A competitive estradiol-binding assay was then devised to measure the ability of coprostanol to compete in the binding of fluorescein-labeled estradiol-albumin to cytosolic proteins. Coprostanol partially reversed the binding of labeled estradiol-albumin to cytosolic proteins with an EC50 of 1 mM. In addition, injections of coprostanol and estradiol-17β led to increased levels of vitellins in the hemolymph of treated mussels. Moreover, incubation of cop in gonad homogenate extracts in the presence of NADPH led to the formation of two compounds, as determined by high-performance thin-layer chromatography. One of these compounds appears to be the C17 oxidation product of coprostanol, whose polarity is similar to that of estradiol. The results present evidence that coprostanol is estrogenic to freshWater mussels.
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evidence of coprostanol estrogenicity to the freshWater mussel elliptio complanata
Environmental Pollution, 2001Co-Authors: F Gagne, C Blaise, B Lachance, G I Sunahara, H SabikAbstract:Coprostanol (5 beta (H)-cholestan-3 beta ol) is a reduced metabolite of cholesterol produced by micro-organisms found in the intestinal tract of mammals. This substance abounds in urban effluents and is accumulated by organisms living in the vicinity of municipal effluent outfalls. In an earlier study, freshWater mussels exposed to contaminated river Water for 62 days accumulated large quantities of coprostanol (Cop) in their soft tissues (16 micrograms/g dry wt.). Moreover, these mussels were found to have elevated levels of vitellin in their hemolymphs, suggesting estrogenic effects. Although municipal wasteWaters are known to contain other estrogenic compounds capable of inducing Vn synthesis in mussels, the estrogenic potential of coprostanol was singled out for examination. To this end, mussels were first injected with concentrations of coprostanol via the abductor muscle route, and allowed to stand in Aerated Water for 72 h at 15 degrees C. The levels of Vn in mussel hemolymph were assayed using the organic alkali-labile phosphate method. A competitive estradiol-binding assay was then devised to measure the ability of coprostanol to compete in the binding of fluorescein-labeled estradiol-albumin to cytosolic proteins. Coprostanol partially reversed the binding of labeled estradiol-albumin to cytosolic proteins with an EC50 of 1 mM. In addition, injections of coprostanol and estradiol-17 beta led to increased levels of vitellins in the hemolymph of treated mussels. Moreover, incubation of cop in gonad homogenate extracts in the presence of NADPH led to the formation of two compounds, as determined by high-performance thin-layer chromatography. One of these compounds appears to be the C17 oxidation product of coprostanol, whose polarity is similar to that of estradiol. The results present evidence that coprostanol is estrogenic to freshWater mussels.
David Z Zhu - One of the best experts on this subject based on the ideXlab platform.
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far field properties of Aerated Water jets in air
International Journal of Multiphase Flow, 2015Co-Authors: Wenming Zhang, David Z ZhuAbstract:Abstract This paper presents an experimental investigation on Aerated Water jets at a 45° angle into air. Different amount of air was injected into the Water jets upstream of a circular nozzle. The focus was on the bulk trajectories of the Aerated jets, as well as the intensity, size and velocity of the Water drops in the far-field. It was found that, the injection of air into Water jets will significantly accelerate Water jet breakup in air, causing the Water jet to spread much wider and more uniform. Meanwhile, Water drop size became substantially smaller, but drop velocity only became slightly smaller. On the horizontal plane at the same elevation of the nozzle, intensity of falling Water drops was noticed to have a Gaussian distribution in the transverse direction, while a left-skewed Gaussian distribution in the longitudinal direction. At the location of maximum intensity, drop size and velocity distributions also approximated Gaussian distributions, while the size distribution could be more complex in a pure Water jet. Terminal Water drop velocity was correlated with drop diameter, and its value was 20% smaller in an Aerated jet than in a pure Water jet for the drops with diameters of 2–10 mm. The energy dissipation of these jets was significant as these jets broke down to drops with relatively small terminal velocities.
Klara G Konya - One of the best experts on this subject based on the ideXlab platform.
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laser flash photolysis studies on the first superoxide thermal source first direct measurements of the rates of solvent assisted 1 2 hydrogen atom shifts and a proposed new mechanism for this unusual rearrangement1
Journal of the American Chemical Society, 2000Co-Authors: Klara G Konya, Thomas Paul, Shuqiong Lin, And Janusz Lusztyk, K U IngoldAbstract:The thermal decomposition of bis(4-carboxybenzyl)hyponitrite (SOTS-1) in Aerated Water under physiological conditions has previously been shown to give the superoxide radical anion in a yield of 40 mol % (Ingold, K. U.; et al. J. Am. Chem. Soc. 1997, 119, 12364). The absolute kinetics of the elementary reactions involved in the cascade of events leading from the first-formed Water-soluble benzyloxyl radical to superoxide have been determined by laser flash photolysis. On the basis of these kinetics it is concluded that SOTS-1 will be suitable for studies of superoxide-induced oxidative stress in most biological systems. A Water-assisted 1,2-H shift converting benzyloxyl into the benzyl ketyl radical is an important step in the above reaction cascade. The kinetics of the 1,2-H shift assisted by H2O, D2O, and a number of nucleophilic alcohols have been measured for the first time. These data have led to a proposed new mechanism involving the initial formation of a ketyl radical anion and an oxonium cation w...
Hideki Takiguchi - One of the best experts on this subject based on the ideXlab platform.
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hydrazine and hydrogen co injection to mitigate stress corrosion cracking of structural materials in boiling Water reactors iv reaction mechanism and plant feasibility analysis
Journal of Nuclear Science and Technology, 2007Co-Authors: Yoichi Wada, Masahiko Tachibana, Kazushige Ishida, Motohiro Aizawa, Motomasa Fuse, Eiichi Kadoi, Hideki TakiguchiAbstract:A calculation model has been developed in order to evaluate effectiveness of hydrazine and hydrogen co-injection (HHC) into reactor Water for mitigation of intergranular stress corrosion cracking of structural materials used in boiling Water reactors (BWRs). The HHC uses the strong reducing power of hydrazine radical, which is produced in the downcomer region under irradiation by γ-rays and neutrons. Some reactions and their reaction rate constants were determined based on experiments which were carried out in Aerated Water, hydrogenated Water, and deAerated Water. The calculated results were in good agreement with experimental data by a factor of two. The model was applied to a BWR and it was found that the HHC cut oxygen and hydrogen peroxide amounts dissolved in reactor Water more effectively than hydrogen Water chemistry alone. Thus, the required amount of hydrogen for hydrazine injection was much lower than that for hydrogen Water chemistry. Consequently, electrochemical corrosion potential of struct...