Non-functional variants of yeast mitochondrial ATP synthase subunit 8 that assemble into the complex

Myocardial and pulmonary beta-adrenoceptors can be imaged with 2-(S)-(-)-(9H-carbazol-4-yl-oxy)-3-[1-(fluoromethyl)ethyl]amino-2- propanol (S-1'-[18F]fluorocarazolol, I). Quantification of unmodified fluorocarazolol in plasma is necessary for analysis of PET images in terms of receptor densities. We have determined I and its radioactive metabolites in rat, sheep and human plasma, using (1) solid-phase extraction (C18) followed by reversed-phase HPLC and (2) direct injection of untreated plasma samples on an internal-surface reversed-phase (ISRP) column. The two methods were in good agreement. Unmodified I decreased from over 99% initially to less than 5%, 5-10% and 20% at 60 min post-injection in rats, sheep and human volunteers, respectively. Protein binding in sheep and human plasma was determined by ultrafiltration. The fraction of total plasma radioactivity bound to protein and the fraction representing unmodified radioligand were linearly correlated, suggesting that fluorocarazolol was more than 70% protein-bound, whereas its metabolites showed negligible protein binding. Direct injection of plasma on an ISRP column seems a convenient method for quantification of lipophilic radioligands such as fluorocarazolol.     

Refinements in validity generalization methods: Implications for the situational specificity hypothesis.

Using a large database, this study examined 3 refinements of validity generalization procedures: (1) a more accurate procedure for correcting the residual standard deviation (SD) for range restriction to estimate SDp, (2) use of r? instead of study-observed rs in the formula for sampling error variance, and (3) removal of non-Pearson rs. The 1st procedure does not affect the amount of variance accounted for by artifacts. The addition of the 2nd and 3rd procedures increased the mean percentage of validity variance accounted for by artifacts from 70 to 82%, a 17% increase. The cumulative addition of all 3 procedures decreased the mean SDp estimate from .150 to .106, a 29% decrease. Six additional variance-producing artifacts were identified that could not be corrected for. In light of these it was concluded that the obtained estimates of mean SDp and mean validity variance accounted for were consistent with the hypothesis that the true mean SDp value is close to zero. These findings provide further evidence against the situational specificity hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fluctuations of Turbulent Bed Shear Stress

With the assumption that the bed shear stress fluctuates in a lognormal fashion, the probability density function (PDF) of the standardized bed shear stress is derived as a function of the relative shear stress intensity. The PDF is more skewed with larger relative intensities, but approaches a Gaussian function when the relative intensity is small. The computed PDF agrees well with the reported experimental data for flows over a smooth boundary. The higher-order moments of the bed shear stress, skewness, and kurtosis, are shown analytically to be also dependent on the relative intensity. The theoretical dependencies are then compared to a number of measurements available in the literature. The Reynolds number effect on the relative intensity is also discussed.     

Mechanisms in damping of mechanical vibration by piezoelectric ceramic-polymer composite materials

The piezoelectric ceramic (piezoceramic) component of a polymer-piezoelectric ceramic composite converts mechanical energy into electrical energy and this electrical energy is dissipated as heat in a load resistance, R _x, simulated by a shunted resistance, but provided in practice by a conductive polymer composite matrix. The composite therefore dissipates the input mechanical energy via the damping mechanism provided by piezoelectric ceramic-conductive matrix material, as well as the conventional viscoelastic damping provided by the polymer. Mathematical models have been developed to characterize the damping behaviour of the composites, and the maximum damping ratio of composites can be as high as 23%. A two degrees-of-freedom (2DOF) experimental setup was developed to test the validity of the models. The experimental results are in good agreement with the theoretical predictions.     

Dissolution Behavior of Griseofulvin Solid Dispersions Using Polyethylene Glycol, Talc, and Their Combination as Dispersion Carriers

Griseofulvin solid dispersions were prepared using polyethylene glycol 6000 (PEG), talc, and their combination as carriers by the solvent method. The dissolution of griseofulvin from these dispersions was studied. It was found that in these carriers the drug dissolution rate was a function of drug loading. The dissolution rate from dispersions prepared using PEG was similar to that from PEG/talc dispersions, especially at a low percentage of drug loading. Dispersions of PEG and PEG/talc provided dissolution rates faster than those from dispersions of talc. The incorporation of talc in PEG yielded dispersions with properties of less tackiness and ease for handling. Dissolution kinetics, based on the Hixson-Crowell equation, was used to determine the characteristics of griseofulvin particles in dispersions. Linear relationships were obtained for PEG and PEG/talc dispersions that indicated the presence of a uniformly sized monoparticulate system, whereas deviation from linearity was observed for talc dispersions. This appeared to be a multiparticulate system in which particles were present as free form and adsorbed form on the surface of talc.     

Identification and characterization of the murine homologue of CD22, a B lymphocyte-restricted adhesion molecule

The human B lymphocyte-specific Ag, CD22, is a cell adhesion molecule expressed on the surface during a narrow window of B cell development, coincident with surface IgD. A ligand for CD22 has recently been identified on human T cells as the low molecular mass isoform of the leukocyte common Ag, CD45RO. CD22 has been reported to function in the regulation of both T and B cell activation in vitro. In this study, we report the isolation and expression of a molecular cDNA clone encoding the murine homologue of CD22, mCD22. Within their predicted protein sequences, murine and human sequences overall have 62% identity, which includes 18 of 20 extracellular cysteines and six of six cytoplasmic tyrosines. BHK cells transfected with mCD22 cDNA specifically adhere to resting and activated T lymphocytes and in addition bound activated, but not resting, B cells. Five Th clones were analyzed for their ability to adhere to mCD22; two Th0 clones and one Th1 clone bound CD22+ BHK transfectants, but not all T cell clones bound CD22+ cells: another Th1 clone and a Th2 clone did not. mCD22+ BHK transfectants were also specifically bound by the B cell-specific mAb, NIM-R6, demonstrating that this mAb is specific for murine CD22. Human cell lines expressing the counter-receptors for human CD22 were also examined for adhesion to the murine CD22 homologue; the epitope responsible for B cell adhesion to CD22 is conserved, whereas the T cell epitope binding to CD22 is not. The cDNA and mAb to murine CD22 will be useful for defining the in vivo function of CD22.     

Measurements of turbulent mass transport of a circular wall jet

The results of a laboratory investigation on the turbulence characteristics of a circular three-dimensional turbulent wall jet are presented. Measurements were taken up to 50 nozzle diameters using combined particle image velocimetry and planar laser induced fluorescence. The results showed that the induced turbulence was still evolving in the present range and had not achieved similarity. While the turbulent intensity for both velocity and concentration increased downstream, the turbulent mass transport showed a decline over distance for both the streamwise and spanwise directions, implying weakening dispersion from the jet core.