Oxygen isotope exchange in nanosized powders of the Al2O3 oxide

Oxygen isotope exchange (OIE) between nanosized powders of the aluminum oxide Al₂O₃ and oxygen-containing gases ¹⁸O₂ and C¹⁸O₂ has been studied in a temperature range of 100?C500°C. The concentration of the oxygen isotope ¹⁸O in the powders was determined by nuclear microanalysis technique (NRA). It has been shown that for this oxide the OIE exhibits a significant size effect. It has been established that the OIE of the Al₂O₃ nanopowder is characterized by a specific time dependence of the concentration of the ¹⁸O isotope at the surface of grains and by a low level of the content of ¹⁸O in the oxide. A linear dependence of the concentration of ¹⁸O in the nanopowders on the specific surface of the nanoparticles has been revealed. The experimental data are discussed in terms of several models of the process of isotope exchange.     

Effect of medicamentous cholesterol control on resources utilization in public health--significance of the Scandinavian Simvastatin Survival Study (4-S Study) for cost control in Swiss health management conditions

Upward spiralling health care expenditures have triggered the need to assess the cost-effectiveness of medical interventions. Specifically, interventions in primary and secondary prevention represent an important field of research. A resource utilization analysis was performed on the basis of the recently published Scandinavian Simvastatin Survival Study. It could be shown that treatment with simvastatin compared to placebo leads to a reduction in patient costs of CHF 8.4 million. This represents a reduction of CHF 3770.- per patient. The effective daily treatment costs can thus be calculated at CHF 1.11, which is equivalent to 36% of the actual acquisition cost per day. These results support the notion that secondary coronary prevention is not only justified from a clinical but also from an economic point of view.     

Self-regulation and school performance: is there optimal level of action-control?

Research on the self-regulatory implications of psychological control suggests that overestimations of one's capabilities may be associated with enhanced performance. We examined this hypothesis in a two-year (three-occasion) longitudinal study of 381 German school children (8-11 years of age). Controlling for gender, grade in school, prior academic achievement, and level of intelligence, we used path analysis to examine the longitudinal relations between overestimations of one's personal agency and subsequent school performance. We expected overestimations of one's agency to facilitate subsequent school performance. Furthermore, we expected that this relationship would be strongest for those with moderate overestimations of their agency. Supporting our first hypothesis, overestimations of one's capabilities were consistently associated with improvements in subsequent school performance. However, our second hypothesis was not supported. The results suggest that overestimating personal agency is one possible mechanism through which one maintains and improves performance.     

The anti-arrhythmic effect of the electrophoresis of a natural shirsal preparation in the 2nd-stage rehabilitation of myocardial infarct patients

Experimental and clinical trials of antiarrhythmic effect of shirsal (natural salt of lake Shira mineral water) have shown that rehabilitation complex including shirsal electrophoresis is beneficial for MI patients with arrhythmia. Shirsal electrophoresis extends indications for sanatorium treatment of MI patients with stable angina of effort (functional class III-IV), grade I-IV arrhythmia, chronic circulatory insufficiency.     

High-resolution imaging at the cellular and subcellular levels in flattened whole mounts of early zebrafish embryos

We describe a rapid and sensitive method for high-resolution imaging at the cellular and subcellular levels in the whole-mount zebrafish embryo. The procedure involves fixing and staining the embryo, followed by deyolking and flattening it under a cover slip, to produce a planar mount that is 20 to 100 microns thick. Such a flattened whole mount allows imaging with a spatial resolution of approximately 500 nm in the x-y plane and does not require the use of embedding, sectioning, confocal microscopy, or computational deblurring procedures. We can resolve all individual nuclei and chromosome sets in the embryo, up to the late gastrula stage (10,000 cell stage). In addition, older embryos (through the segmentation stage) can also be examined, with the preservation of significant morphological detail. Because of its ability to resolve subcellular detail, the flattened whole-mount method can provide significant biological information beyond what can be obtained from conventional (three-dimensional) whole mounts. We have used the flattened whole-mount method to study subcellular events related to progression through the cell cycle or to apoptosis, in cells of the early zebrafish embryo. A specific DNA-binding dye (Hoechst 33258) or an antibody against a chromosomal protein (histone H1) was used to stain the nuclei of individual cells in the embryo. This allowed us to determine the spatial positions of all the individual cells, and also their stages in the cell cycle. A terminal transferase (TUNEL) assay was used to detect apoptotic cells. This combination of specific stains allowed us to study the behaviors of groups of cells in situ, within the developing zebrafish embryo.     

What is the evidence that osteoarthritis is genetically determined?

Although for many years it was speculated that osteoarthritis was genetically determined, little data were available to support this contention. A major problem with early work was a lack of consistency in the definition of osteoarthritis. Based on a radiographical definition of osteoarthritis, which is currently the optimal method for epidemiological and genetic studies, data from a recent twin study have provided an estimate of the hereditable component of osteoarthritis to be in the order of 50 to 65%. In addition, sophisticated molecular biology techniques are being increasingly used to explore potential genetic abnormalities in cartilage and matrix components in osteoarthritis. These exciting new data are examined as we address the role of genetic factors in osteoarthritis.     

Substrate selectivity and biochemical properties of 4-hydroxy-2-keto-pentanoic acid aldolase from Escherichia coli

4-Hydroxy-2-keto-pentanoic acid aldolase from Escherichia coli was identified as a class I aldolase. The enzyme was found to be highly selective for the acetaldehyde acceptor but would accept alpha-ketobutyric acid or phenylpyruvic acid in place of the pyruvic acid carbonyl donor.