Cluster determination

Hyperfine Coupling Values of the Nitrogen Ligands of Rieske and Rieske-Type Clusters Determined by ENDOR and ESEEM Spectroscopy... 

CBP Cromolyn-binding protein CCK Cholecystokinin CCR Creatinine clearance rate CD Cluster of differentiation (a system of nomenclature for sur ce molecules on cells of the immune system) cluster determinant CDl Cluster of differentiation 1 also known as MHC class I-like surfitce glycoprotein... 

The first study was conducted to determine whether carotenoids and cholesterol share common pathways (transporters) for their intestinal absorption (During et al., 2005). Differentiated Caco-2 cells on membranes were incubated (16 h) with a carotenoid (1 pmol/L) with or without ezetimibe (EZ Zetia, an inhibitor of cholesterol transport), and with or without antibodies against the receptors, cluster determinant 36 (CD36) and scavenger receptor class B, type I (SR-BI). Carotenoid transport in Caco-2 cells (cellular uptake + secretion) was decreased by EZ (lOmg/L) as follows P-C and a-C (50% inhibition) P-cryptoxanthin and LYC (20%) LUT ZEA (1 1) (7%). EZ reduced cholesterol transport by 31%, but not retinol transport. P-Carotene transport was also inhibited by anti-SR-BI, but not by anti-CD36. The inhibitory effects of EZ and anti-SR-BI on P-C transport... 

Model of a supramolecular structure of polymolecular ensembles or clusters, determined by interaction and mutual arrangement of the forming molecules. At this level, the specific mechanisms of supramolecular chemistry, including molecular recognition, self-assembly, etc. [4] can be allocated. In most cases, it is possible to limit this area to objects with the sizes under 1 to 2 nm, since further increase in the sizes admits application of statistical concepts like phase and interphase surface. 

As they differentiate into populations with differing functions, B and T cells acquire molecules on their surfaces that reflect their specializations. It is possible to produce homogenous antibodies of a single specificity, termed monoclonal antibodies, which can recognize such surface markers. When laboratories from all over the world compared the monoclonal antibodies they had raised, it was found that clusters of monoclonal antibodies were recognizing the same molecule on the surface of the lymphocyte. Each surface molecule so defined was referred to as a CD molecule (Table 2), where CD refers to a cluster determinant. 

Figure 5.44 depicts the central section of a possible defect cluster for FeO. (a) Determine the vacancy interstitial ratio for this cluster, (b) Assuming that this section is surrounded by Fe ions and oxide ions in octahedral sites as in the Koch-Cohen cluster, determine the formula of a sample made totally of such clusters, (c) Determine the numbers of Fe and Fe ions in octahedral sites. 

The overall relative orientation of the secondary structures of an enzyme determines its three-dimensional shape, or tertiary structure. Some enzymes require multiple copies of the same enzyme to function. The individual enzymes cluster into groups of two or more (called dimers, trimers, etc.) and are held together by intermolecular forces. The relative positioning of the separate enzymes in the cluster determines the overall structure, or quaternary structure, of the supramolecular complex. While all enzymes have tertiary structure, only clusters of multiple enzyme subunits have quaternary structure. The overall folded conformation of a protein in its active, catalytic form is called the active or native conformation. 

The Kirkwood—Buff theory of solution was used to investigate the formation of clusters in aqueous alcohol solutions. The correlation volume (volume in which the composition differs from the bulk one) was calculated for the systems 1-propanol—water and fert-butyl alcohol—water and compared with the sizes of clusters determined by various physical techniques. The calculations indicated that two types of clusters, alcohol- and water-rich clusters, are present in the solutions. Their sizes, which depend on composition in a similar way, exhibit maxima in the water-rich region. The calculated values are in a satisfactory agreement with experiment. The composition inside the clusters (the local composition) was calculated as a function of the correlation volume for dilute aqueous methanol, ethanol, propanols, and terf-butyl alcohol solutions. The results were compared with the local compositions provided by the Wilson and NRTL equations. 

A satisfactory agreement was found between the sizes of the clusters determined experimentally and calculated. For the... 

Pure solvents Both UV-vis and fluorescent probes, which exhibit solvatochromic shifts, have been used to study clustering. Solvatochromic shifts are caused by the same types of solute-solvent intermolecular forces (i.e. dispersion, induction, and dipole-dipole forces) that influence solubilities, interacting over the same range. Consequently, the values of clustering determined spectroscopically are appreciate for considering the effect of clustering on solubilities. 

Fig. 10.43. LUMOsi ( x ), LUMOq ( A ), HOMOsi ( + ) and HOMOq ( 0 ) ofSi 0, clusters determined based on the calculations...

FIG. 19. Overview of deformations of sodium clusters determined from studies of the optical absorption of the plasmon resonance [155,156]. 

We decompose into its closed, open and quasi-open components. The open and the quasi-open components of Eq. (52) would be used in an appropriate manner to generate a set of sufficiency conditions to define the cluster determining equations. The closed components will be used to define... 

Many main-group atoms have been found to occupy interstitial positions in transition metal carbonyl clusters and there are now examples of H, B, C, N, O, Si, P, S, Ge, As, Sn, and Sb atoms being encapsulated, either fully or partially, within a metal skeleton. In general, the size limitations associated with the internal cavity of the cluster determine the type of atom which can occupy the interstitial site. Although the radius of the cavity is determined primarily by the nuclearity and geometry of the cluster, the size of the metal atoms relative to that of the interstitial atom is a critical factor, and clusters with larger cavities are observed as the ratio of the covalent radius of the main-group atom to that of the transition metal atoms increases. 

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