Aggregation causes

Photochemistry can be used to demonstrate solvent effects in supercritical fluids. The analysis revealed trimodal fluorescence lifetime distributions near the critical temperature, which can be explained by the presence of solvent-solute and solute-solute clustering. This local aggregation causes an increase in nonradiative relaxations and, therefore, a decrease in the observed fluorescence lifetimes. Concentration and density gradients are responsible for these three unique lifetimes (trimodal) in the supercritical fluid, as contrasted with the single lifetime observed in a typical organic solvent. The... 

While the properties of the cementitious binder are known to be important, it is also recognized that certain aggregates cause further problems especially in the presence of salts and deicing agents. The decrease in durability has been attributed to both physical mechanisms (10) and chemical processes (11). 

PAR-1, results in the formation of platelet aggregation causing thrombotic disorders such as myocardial infarction, stroke, angina, and atherosclerosis. Benzimidazolone peptidomimetic derivatives effective as thrombin receptor antagonists have been prepared to address this disorder. 

These results led to the conclusion that denaturation and/or insolubilization of actomyosin and myosin during frozen storage is a result of aggregation caused by the progressive increase in intermolecular crosslinkages due to formation of hydrogen bonds, ionic bonds, hydrophobic bonds and disulfide bonds. 

Denaturation and aggregation caused by heat treatment will be discussed for two completely different protein systems namely a soy and a whey protein system. Although the two protein systems are different in character they both have the ability to form a gel after heat treatment. 

Hemoglobin dramatically demonstrates how sensitive the function of a biomolecule is to its structure. In certain people, in the synthesis of the proteins needed for hemoglobin, an improper amino acid is inserted into the protein in two places. This may not seem very serious, since there are several hundred amino acids present. However, because the incorrectly inserted amino acid has a nonpolar substituent instead of the polar one found on the proper amino acid, the hemoglobin drastically changes its shape. The red blood cells are then sickle-shaped rather than disk-shaped, as shown in Fig. 20.37. The misshapen cells can aggregate, causing clogging of tiny capillaries. This condition, known as sickle cell anemia, is the subject of intense research. 

As mentioned previously, the interactions of the chromophores with extended tt-system in densely packed solids like LBK films significantly influence the optical properties. In particular the aggregation causes a significant peak shift, the direction and extent of which depends on the number of aggregated chromophores and their distance from each other in the ag egate. Furthermore, a particular influence on the extent and direction of the peak shift is found for the orientation of the chromophores to each other i.e., the angle of inclination 6 as defined in Figure 6.6. This phenomenon can be described by Me Rae and Kasha s molecular exciton model or the more elaborated extended dipole model by Kuhn et... 

Figure 4. The particle flux spectrum. The vertical axis shows the rate of export of nitrogen by particles in the different sections the other axes are as in Figure 3. The formation of high concentrations of aggregates causes the major loss to be in the midrange particles.

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