Formation, possible roles

Raines EW, Ross R. Biology of atherosclerotic plaque formation possible role of growth factors in lesion development and the potential impact of soy. J. Nutr. 125, 624S-630S, 1995. 

StiU another possible role of supersaturation is that it affects the solution stmcture and causes the formation of clusters of solute molecules. These clusters may participate in nucleation, although the mechanism by which this would occur is not clear. Evidence of the existence of cluster formation in supersaturated solutions has been presented for citric acid (21) while others have examined the phenomenon in greater detail (22,23). 

Oxidant Formation. The role of HO. in controlling the time-scale and severity of tropospheric oxidant pollution may be seen from the parameterization of O Brien and co-workers (75,76). The simplest possible mechanism for oxidant (Le. ozone, PAN, H2O2, etc.) formation consists simply of the reaction of an individual NNlHCj with HO. to convert the NMHCj to a generic product(s) PRODj, followed by removal of the product by HO. (PROD photolysis may be important, but is ignored here)... 

While the fluid mosaic model of membrane stmcture has stood up well to detailed scrutiny, additional features of membrane structure and function are constantly emerging. Two structures of particular current interest, located in surface membranes, are tipid rafts and caveolae. The former are dynamic areas of the exo-plasmic leaflet of the lipid bilayer enriched in cholesterol and sphingolipids they are involved in signal transduction and possibly other processes. Caveolae may derive from lipid rafts. Many if not all of them contain the protein caveolin-1, which may be involved in their formation from rafts. Caveolae are observable by electron microscopy as flask-shaped indentations of the cell membrane. Proteins detected in caveolae include various components of the signal-transduction system (eg, the insutin receptor and some G proteins), the folate receptor, and endothetial nitric oxide synthase (eNOS). Caveolae and lipid rafts are active areas of research, and ideas concerning them and their possible roles in various diseases are rapidly evolving. 

Sinaceur, J., Ribiere, C., Sabourault, D. and Nordmann, R. (1985). Superoxide formation in liver mitochondria during ethanol intoxication possible role in alcohol toxicity. In Free Radicals in Liver Injury (eds. G. Poli, K.H. Cheeseman, M.U. Dianzani and T.F. Slater) pp. 175-177. IRL Press, Oxford. 

A wider problem exists with the possible role of liquid medications in dental caries formation [63], The extent of acid production in the oral cavity is closely related to caries formation. In a study of liquid medication, investigators have observed that medications with sucrose concentrations higher than 15% were able to significantly lower pH there was an inverse relation between sucrose content and a decrease in oral cavity pH [64], In a comparison of sorbitol and sucrose-sweetened liquid iron preparations, only sucrose-containing products produced a significant decrease in oral cavity pH [65],... 

Two possible roles for the metal ion in a template reaction have been delineated (Thompson Busch, 1964). First, the metal ion may sequester the cyclic product from an equilibrium mixture such as, for example, between products and reactants. In this manner the formation of the macrocycle is promoted as its metal complex. The metal ion is thus instrumental in shifting the position of an equilibrium - such a process has been termed a thermodynamic template effect. Secondly, the metal ion may direct the steric course of a condensation such that formation of the required cyclic product is facilitated. This process has been called the kinetic template effect. 

Polymerisation of HCN species is also possible once the initial monomers have been formed by the reactions with nitrogen HCN polymers have been postulated in many places in the solar system, from the clouds of Jupiter and Saturn to the dark colour of the surface of comet Halley, not to mention its possible role in the formation of the prebiotic molecule adenine. Photolysis of HCN produces CN and then the formation of nitrile polymers ... 

At present, numerous free radical studies related to many pathologies have been carried out. The amount of these studies is really enormous and many of them are too far from the scope of this book. The main topics of this chapter will be confined to the mechanism of free radical formation and oxidative processes under pathophysiological conditions. We will consider the possible role of free radicals in cardiovascular disorders, cancer, anemias, inflammation, diabetes mellitus, rheumatoid arthritis, and some other diseases. Furthermore, the possibilities of antioxidant and chelating therapies will be discussed. 

Ji,Y., Akerboom,T.P.M., Sies, H., Microsomal formation of S-nitrosoglutathione from organic nitrites possible role of membrane-bound glutathione transferase. Biochem. J. 313 (1996), p. 377-380... 

These results therefore indicate that a significant portion (ca. two-thirds) of the C02 formed during the positive-going sweep arises from electrooxidation of benzaldehyde (or possibly other interfacial species) rather than from adsorbed CO. In addition, the SFAIR spectra indicate that the formation of C02 commences only upon CO electrooxidation, and essentially no C02 from a source other than previously adsorbed CO appears until the CO coverage becomes very small (6 < 0.1). Although these results do not rule out the possible role of adsorbed CO as an intermediate in the electrooxidation of solution benzaldehyde to C02, they suggest that the majority of the adsorbate acts as a poison for this process, removal of which is required for initiation of the electrocatalytic pathway. 

The formation of both isomeric chlorides 147 and 148 and the corresponding methoxy adducts 149 and 150 in methanol is at variance with the behavior observed in AcOH/ LiC104, where only the acetoxy species 140 is formed. This has been interpreted by taking into account the possible role of a specifically solvated carbenium ion pair, such as 145, prior to the formation of a free carbenium ion of type 144. 

Ahokas, J.T., Pelkonen, 0. and K rki, N.T. The possible role of trout liver aryl hydrocarbon hydroxylase in activating aromatic polycyclic carcinogens. In Jollow, D.J. Kocsis, J.J., Snyder, R. and Vainio, H. (Eds.) Biological Reactive Intermediates. Formation, Toxicity, and inactivation (1977) Plenum Press, New York, pp 162-166. 

Y. Ji, T. P. M. Akerboom, H. Sies, Microsomal Formation of S-Ni IrosogIulathione from Organic Nitrites Possible Role of Membrane-Bound Glutathione Transferase , Biochem. J. 1996, 373,377-380. 

The question we address now is that of the possible role of single electron transfer in substitution reactions that, unlike SrnI reactions, are not catalysed by electron injection. The problem is twofold. One side of it consists in answering the questions do bond breaking and bond formation belong to two different and successive processes, i.e. (135) followedhy (136), or, more... 

The observed ambient organic aerosol formation rates are also consistent with those estimated by extrapolation of smog-chamber kinetic data. Other heavy unsaturates, such as styrene and indene, are present in the atmosphere and may contribute, in part, to the formation of benzoic acid and homophthalic acid, respectively. Diesel exhaust and industrial emission are possible sources of such heavy unsaturates. Diolefins of C6+ are not present in gasolines and exhaust gases and have not been found in the atmosphere, and their possible role as precursors of the Cs-7 difiinctional acidic compounds is seriously challenged. Lower diolefins are emitted in automobile exhaust. Examination of vapor-pressure data indicates that the bulk of their expected photooxidation products remains in the gas phase, including most of the less volatile C3-4 dicarboxylic acids. 

Without ion-radical initiation, the yield of the resulted product reaches 50% for 24 h. Practically the same yield can be achieved for the same time in the presence of tris(4-bromophenyl)ammoniumyl hexachloroantimonate and for only 6 h on sonication (Nebois et al. 1996). Sonication accelerates the rate-determining formation of the diene cation-radical. Of course, hydroxynaphthoquinone is strong enough as an electron-acceptor with respect to 2-butenal Af,Af-dimethylhydrazone. Therefore, the question remains whether sonication is more or less the general method for the initiation of ion-radical cycloaddition. A possible role of sonication in optimization of ion-radical reactions was considered in Section 5.2.5. 

Bujdak, J., Slosiarikova, H., Texler, N., Schwendinger, M., and Rode, B. M. (1994). On the possible role of montmorillonites in prebiotic peptide formation. Monats. Chem., 125, 1033-9. 

Because of its inhibition of the formation of Man-P-Dol and GlcNAc-PP-Dol, diumycin may be useful in attempts to discover possible roles of Glc-P-Dol in D-glucan formation, because it would block concomitant formation of D-mannan and glycosylation of proteins. 

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