Oxide theory

Certain aspects of our results, however, while not invalidating the /7-oxidation theory of the w-fluorocarboxylic acids, do indicate that / -oxidation is not the only factor concerned with the alternation of toxic properties. 

Although our results support the / -oxidation theory, one point must not be overlooked, namely, that fluoroacetic acid is not the actual toxic agent and has to be converted into fluoro-citrate before exerting its activity (see p. 142). It should also be noted that American workers1 showed that both methyl y-fluorobutyrate and methyl -fluorocrotonate,... 

We then sought an independent method of proving the /9-oxidation theory.1 This consisted in synthesizing w-fluoro compounds which contained the skeleton of the toxic members, but which could not undergo /9-oxidation in the body. If these new compounds had been toxic, the /9-oxidation theory would have had to be abandoned. Actually they were non-toxic compared with the parent acid , and so excellent support, of a kind hitherto not considered, was obtained. 

Thomsen, L. L. and Olesen, J. Nitric oxide theory of migraine, Clin. Neurosci. 1998, 5, 28-33. 

One of the first persons to study the oxidation of organic compounds by animal tissues was T. Thunberg, who between 1911 and 1920 discovered about 40 organic compounds that could be oxidized by animal tissues. Salts of succinate, fumarate, malate, and citrate were oxidized the fastest. Well aware of Knoop s (3 oxidation theory, Thunberg proposed a cyclic mechanism for oxidation of acetate. Two molecules of this two-carbon compound were supposed to condense (with reduction) to succinate, which was then oxidized as in the citric acid cycle to oxaloacetate. The latter was decarboxylated to pyruvate, which was oxidatively decarboxylated to acetate to complete the cycle. One of the reactions essential for this cycle could not be verified experimentally. It is left to the reader to recognize which one. 

Considerable controversy exists as to the identity of the active antiknock species when tetraethyllead is used in the fuel. Egerton and coworkers (44-8) concluded that antiknock substance must be oxidized, molecularly dispersed, and capable of existence in several stages of oxidation. Chamberlain, Hoare, and Walsh (21), in a series of detailed and comprehensive studies, concluded that tetraethyllead acts as an inhibitor by virtue of forming lead oxide (PbO). A large amount of additional evidence has been cited supporting the metal oxide theory (57, 79, 99,128,138). 

Assuming known values for the ph qh and R cv> and assuming a known evaporation rate for the oxide, we have a set of N equations for the growth rates dL,/dt of the N layers. This formulation for cation vacancy growth is general from the standpoint that no specific coupled-currents oxidation theory has yet been invoked to evaluate the currents J/cv) through the individual layers. 

The author s position is roughly that implied in Burns remark above. The fuel cell community is young and interdisciplinary. Retired fuel cell technologists are still rarities, so that distillations of long-term extensive experience are hard to come by. Moreover, such experience will not have been against the new background fully developed in this book for the first time. The new fuel cell isothermal oxidation theory is remarked upon in the foreword, and was partly introduced by Barclay... 

Exception to this oxide theory, however, has been taken by Muller and Konigsberger,5 on the ground that the reflecting power of iron, rendered passive anodically when immersed in alkaline solution, remains undimmed, whereas if a layer of oxide were formed an alteration would be expected. But it is not necessary to postulate the formation of a thick layer of oxide. If of merely molecular dimensions, it would still preserve the underlying metal from attack, whilst a thickness comparable with that of the length of a light wave would be necessary to affect the reflecting power.6... 

On the other hand, when highly polished iron rods are immersed in concentrated nitric acid a visible dulling usually ensues.1 This is exactly what might be anticipated m accordance with the oxide theory, inasmuch as such a powerful oxidiser might easily induce the formation of a sufficient thickness of oxide to be visible. 

This, like the oxide theory, has much to recommend it. An explanation is afforded for the superficial nature of passivity, and the theory also offers an explanation for the passivity induced in certain cases where oxygen cannot be the cause. 

Centers re-examined the published information about the performance of antimony trioxide, and rejected both the sacrificial oxidation theory and the oxide interaction concept. He concluded that antimony trioxide and certain other oxides and sulphides improve performance by providing a soft component which enables molybdenum disulphide more readily to acquire the optimal basal plane orientation for low friction and wear. However, he used compacts, and it is difficult to understand how his conclusion could apply to burnished films or well run-in films which already approach perfect crystallite orientation. His rejection of the sacrificial oxidation theory is based on a report by Gardos and McConnell , which does not include all of... 

ADDITION TO CHAPTER XXVIII An oxidation theory of the biogenesis of thebaine was briefly advanced by Robinson in 1948 and reference was made to the formation of bis-nor-laudano sine alkaloids such as oxyacanthine as affording some help in regard to the nuclear oxidations required for the above hypothesis . Robinson added, The formation of such diphenyl ethers is clearly an oxidative process it can of course be imitated in the laboratory in various ways on much simpler substances [5]. This discussion of the problem pre-dates the more elaborate theory outlined by Schop f. 

Lavoisier clarified these facts through the synthesis and the decomposition of mercury oxide. Fie discovered the Law of Conservation of Mass and the Oxidization Theory. With these discoveries, the long era of alchemy and Phlogiston Theory was laid to rest and chemistry came forward as a leading scientific discipline. 

In other experiments of burning processes, one should use good scales. Historically, the scales have played an important role regarding knowledge of the oxidation theory French scientist Lavoisier observed the formation and... 

Other proposed mechanisms for the effects of isoflavones include the prevention of atheroma formation through their antioxidant ability, and recently, the oxidative theory of atherogenesis has provided another avenue of therapy involving antioxidants [129], According to this theory, antioxidants should protect lipoproteins against oxidative modification and reduce the biological consequences. Thus, Tikkanen et al [130] showed that the intake of soy protein containing 60 mg of isoflavones per... 

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