Nitric oxide disappearance

If the rate (at a particular instant) at which hydrogen disappears was found to be 0.01 moldm s", what is the simultaneous rate at which (I) nitric oxide disappears, (II) nitrous oxide appears, (III) water appears ... 

Another redox reaction leading to arenediazonium salts was described by Morkov-nik et al. (1988). They showed that the perchlorates of the cation-radicals of 4-A,A-dimethylamino- and 4-morpholinoaniline (2.63) react with gaseous nitric oxide in acetone in a closed vessel. The characteristic red coloration of these cation-radical salts (Michaelis and Granick, 1943) disappears within 20 min., and after addition of ether the diazonium perchlorate is obtained in 84% and 92% yields, respectively. This reaction (Scheme 2-39) is important in the context of the mechanism of diazotization by the classical method (see Sec. 3.1). 

At temperatures near 100° Horiguchi and associates (117) have shown that CO reacts with the superoxide ion on ZnO, but the Or spectrum remained at a fixed level following the addition of a mixture of CO and 02. Hydrogen did not react with 02- at that temperature. Upon addition of nitric oxide at room temperature the Oi signal instantaneously disappeared. 

Lifetime of nitric oxide is an important parameter of its reactivity. Measurement of NO in intact tissue yielded a value in the order of 0.1 s [35] although preliminary estimates gave a much bigger lifetime. It has been accepted that the main reason for the rapid disappearance of NO in tissue is its reaction with dioxygen, which proceeds in aqueous solution with the following overall stoichiometry ... 

However, this reaction is too slow with physiologically relevant NO concentrations, even though its rate in hydrophobic biological membranes can be about 300 times higher [36]. Therefore, it has been proposed [37] that the accelerated disappearance of nitric oxide in tissue is explained by its interaction with superoxide. The extravascular lifetime of nitric oxide is estimated to be in the range from 0.09 to>2s, depending on the dioxygen concentration and distance from the vessel. 

The third chemical equation, involving nitric oxide, represents a termolecular reaction. Therefore, the overall order of the reaction is expected to exceed that of the second-order reaction generally assumed in the pre-mixed gas burning model. The high exothermicity accompanying the reduction of NO to N2 is responsible for the appearance of the luminous flame in the combustion of a double-base propellant, and hence the flame disappears when insufScient heat is produced in this way, i. e., during fizz burning. 

The rate of a reaction is defined as the change in the concentration of a reactant or product with time. For simple reactions occurring with unit stoichiometry, the rate expressed in terms of reactant disappearance is the same as the rate in terms of product formation. For example, for reaction (4), the reaction of ozone with nitric oxide,... 

Measurement of nitric oxide by absorption into hydrophobic tubing. The apparent disappearance of nitric oxide is due to uptake into the hydrophobic tubing and is independent of the oxygen concentration in the solution. Peroxynitrite (ONOO") rapidly destroys nitric oxide as shown by the rapid decrease in the signal. The details of the basic apparatus are shown in Fig. 18. 

Experiments with similarly small values of nitric oxide in the presence of air were performed also by Bufalini and Stephens66 and by Greig and Hall.173 The latter obtained some very important information by monitoring NO disappearance by infrared absorption while also monitoring N02 concentration. They found that although the rate constant obtained by NO disappearance was constant at about 1 x 104... 

Clyne, Thrush, and Wayne107 reexamined the chemiluminescence from the nitric oxide-ozone reaction and found its spectrum to be similar to that of the thermal emission of N02 at 1200°K. They concluded that the spectra represented transitions from similar low-lying vibration levels of the same excited electronic state of NOa to the ground state. By measuring the decay in chemiluminescence down a flow tube, they obtained the value of the rate constant between 216 and 322°K. The partial pressures of ozone and nitric oxide were 5 x 10-3 and 2 x 10 2 torr, respectively, in an argon carrier at a total pressure of 2 torr. In the presence of excess nitric oxide, they assumed the logarithmic disappearance of ozone proportional to [NO], so that... 

Similarly, oceanic nitrite (NO, 1 photolysis by natural light produces detectable concentrations of nitric oxide (NO). This latter forms in tile oceans during daylight and disappears rapidly at sunset when recombination occurs NO --------- NO + O--------- NO.. 

Gonadorelin inhibits nitric oxide-mediated arterial relaxation, which disappears within 3 months after stopping treatment. This effect was abolished with add-back hormone replacement in a prospective, randomized study of 50 women treated for 6 months (6). 

Syncoilin is highly expressed in skeletal and cardiac muscle and is localized to the neuromuscular junction, sarcolemma, and Z-lines. Likewise, desmuslin is expressed in heart and skeletal muscle and localized at Z-lines. It was shown that syncoilin and desmin interact directly, but do not coassemble into filaments in fact, evidence suggests that syncoilin does not participate in filament formation at all. It was proposed that syncoilin helps anchor the desmin IF network at the sarcolemma and the neuromuscular junction (Poon et al, 2002). More recent work has analyzed patients with a desmin-related cardiomyopathy in which patients with desmin accumulation also exhibit an upregulation of syncoilin and accumulation of other elements of the DPC. These defects were correlated with a disappearance of both o-dystrobrevin-l and neuronal nitric oxide... 

The brown ring is due to the formation of the [Fe(NO)]2+. On shaking and warming the mixture the brown colour disappears, nitric oxide is evolved, and a yellow solution of iron(III) ions remains. The test is unreliable in the presence of bromide, iodide, nitrite, chlorate, and chromate (see Section IV.45, reactions 3 and 4). 

The dark colour of the nitric oxide derivative may be utilised in the volumetric estimation of nitric acid, as its appearance depends upon the presence of excess ferrous sulphate in solution. Further addition of nitric acid oxidises this remaining ferrous sulphate and, when oxidation is complete, the colour disappears. The discharge of... 

For years, articles in the medical literature detailed the activities and the functions of EDRF. Even before scientists knew what it was, they recognized the enormous importance of EDRF. Despite the difficulty of isolating and identifying something that appeared and disappeared in a nanosecond, EDRF was discovered to be a gas, nitric oxide (NO). That discovery earned three doctors the Nobel Prize in medicine in 1998. 

A nitrite reductase in H. marismortui[ A5] causes the disappearance of nitrite in the presence of dithionite with either methylviologen or the organism s ferredoxin as the electron mediators. The product of reduction is presumed to be nitric oxide. 

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