Oxygen receptor

Both these reactions take place at temperatures between 800 and 900 C. The iron oxide acts as a solid state oxygen source for the oxidation of the combustible part of the producer gas (reaction 1) and as an oxygen receptor in the subsequent water splitting reaction. It is of central importance that the bulk of the oxide material can be cycled between the two oxidation states without breaking apart. The close relationship between the crystallographic structure of Fej04 and FeO is an inqjortant prerequisite to fulfil this requirement. In this context it is important to keep the reaction conditions such that reduction to metallic iron does not occur. 

Burn injvuy —> inhalation of smoke and ashes alveoli blockage carbon monoxide inhalation -4 carboxyhemoglobin formation (carbon monoxide binding to oxygen receptors) heat damage to bronchioles and alveoli -> damage and collapse of alveoli hypoxia and hypercarbia (elevated carbon dioxide) with related imbalances... 

Trinder, P. (1969). Determination of glucose in blood using glucose oxidase with an alternative oxygen receptor. Ann. Clin. Biochem. 6 24. 

Respiration, or biological oxidation, is the use of oxygen as an electron receptor in the cataboHc degradation of an organic and can occur either aerobically or anaerobically. Aerobic respiration uses free oxygen as an electron receptor whereas anaerobic respiration uses inorganic oxygen. In both cases, however, water and carbon dioxide are the principal end products. 

Thermodynamically it would be expected that a ligand may not have identical affinity for both receptor conformations. This was an assumption in early formulations of conformational selection. For example, differential affinity for protein conformations was proposed for oxygen binding to hemoglobin [17] and for choline derivatives and nicotinic receptors [18]. Furthermore, assume that these conformations exist in an equilibrium defined by an allosteric constant L (defined as [Ra]/[R-i]) and that a ligand [A] has affinity for both conformations defined by equilibrium association constants Ka and aKa, respectively, for the inactive and active states ... 

In the interstitium, angiotensin II induces proliferation of mesangial cells and fibroblasts and the synthesis of collagen and other matrix molecules by these cells via the ATI receptor. Moreover, by the concomitant stimulation of chemoattractant cytokines, inflammation is induced. These processes are mediated by endothelin, transforming growth factor(3, and reactive oxygen species, and finally lead to interstitial fibrosis and glomerulosclerosis observed in hypertension and diabetes. 

Aizenman E, Hartnett KA, Reynolds IJ Oxygen free radicals regulate NMDA receptor function via a redox modulatory site. Neuron 5 841—846, 1990... 

The process of activation of neutrophils is essentially similar. They are activated, via specific receptors, by interaction with bacteria, binding of chemotactic factors, or antibody-antigen complexes. The resultant rise in intracellular Ca affects many processes in neutrophils, such as assembly of micrombules and the actin-myosin system. These processes are respectively involved in secretion of contents of granules and in motility, which enables neutrophils to seek out the invaders. The activated neutrophils are now ready to destroy the invaders by mechanisms that include production of active derivatives of oxygen. 

AH,B units at opposite ends of the molecule, just as in the case of l,3-dihydroxy-2-propanone (see Section II,3,a,ii), so that the molecule cannot align itself correctly on the receptor surface.Odorant molecules have been observed to behave similarly. The poor polarization of the taste receptor is enhanced by the combined effect of (a) the absence of a ring-oxygen atom, and hence a polar center, and (b) the presence of hydrophobic, methylene groups. 

Fig. 31.— The Two Possible Conformations of Aspartame (18) Interacting with the Receptor Site." [Key O, carbon G, oxygen , nitrogen and o, hydrogen.]...

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