Edge effect on unidirectional composite observed during acoustic emission monitoring of damage

Since submitting this letter, Dr Daniel Valentin has died following a serious illness. The sad loss of this leading young researcher is very much regretted. His memory will live on through his many distinctive contributions to the literature.     

A protein kinase is located in the micellar fraction of fresh pasteurized skimmed farm milk

Recombinant protein kinase CK2 from the yeast Schizosaccharomyces pombe is able to phosphorylate casein in skimmed pasteurized milk. We could incorporate up to 540 pmol of phosphate into 50 microg milk proteins, i.e., 0.26 P/mol caseins. To better understand the action of protein kinase CK2 on milk proteins, we have compared the action of rspCK2alpha on milk, and on different casein micellar subfractions isolated from milk by ultracentrifugation. In contrast to the situation observed with phosphocaseinate, alpha(s) casein was the best substrate for rspCK2alpha, whether milk or micellar fractions were used as substrates. We have characterized the protein content of different micellar fractions obtained by ultracentrifugation of cow milk using capillary zone electrophoresis. We confirm that the kappa casein content of micelles largely decreases when their size increases. In contrast, the alpha(s) casein content slightly increased with micelles size and beta casein content remained constant. All of the micellar fractions were substrates for rspCK2alpha, but a significant amount of intrinsic protein kinase activity was also found. The intrinsic protein kinase used added ATP as phosphate donor, and was only slightly sensitive to high heparin concentration. It could phosphorylate micellar casein in milk ultrafiltrate, in the absence of addition of any metallic cofactor. Its activity was only slightly affected by the addition of either MgCl2 or MnCl2. CaCl2 activated the enzyme significantly. The intrinsic kinase lost its activity with time, and could incorporate from 9 to 26% of the total phosphate incorporated in the presence of rspCK2a. Alpha(s) casein was the best substrate of the intrinsic kinase, followed by beta casein. In the presence of CaCl2, the intrinsic kinase was found to incorporate up to 470 pmol of phosphate into 50 microg of milk proteins.     

A framework for assessing the impact of ionising radiation on non-human species. ICRP Publication 91

In its 1990 Recommendations, the ICRP indicated that it believed that the standards of environmental control needed to protect man to the degree currently thought desirable would ensure that other species are not put at risk. The ICRP considers that its system of radiological protection has provided a fairly good indirect protection of the human habitat. However, no internationally agreed criteria or policies explicitly address protection of the environment from ionising radiation, and it is difficult to determine or demonstrate whether or not the environment is adequately protected from potential impacts of radiation under different circumstances. The present report suggests a framework, based on scientific and ethical-philosophical principles, by which a policy for the protection of non-human species could be achieved. The primary purpose of developing such a framework is to fill a conceptual gap in radiological protection; it does not reflect any particular concern over environmental radiation hazards. The proposed framework is designed to harmonise with the ICRP's approach to the protection of human beings, but does not intend to set regulatory standards. Instead, the proposed framework is intended to be a practical tool to provide high-level advice and guidance for regulators and operators. An agreed set of quantities and units, a set of reference dose models, reference dose-per-unit-intake (or unit exposure), and reference fauna and flora are required to serve as a basis for the more fundamental understanding and interpretation of the relationships between exposure and dose and between dose and certain categories of effect, for a few, clearly defined types of animals and plants. As a first step, a small set of reference fauna and flora with supporting databases will be developed by the ICRP. Others can then develop more area- and situation-specific approaches to assess and manage risks to non-human species.     

Development of alternative fuel assembly for WWER-1000 reactor

An alternative design of fuel assembly has been developed for the WWER-1000 reactor with the aim of assuring a geometrical stability of the core during operation. The fuel assembly provides enhanced safety and substantial improvement in the WWER-1000 fuel cycle economics.     

Characterization of an exocellular protein phosphatase with dual substrate specificity from the yeast Yarrowia lipolytica

In previous work, the major endocellular protein phosphatase activity has been identified in the secretory yeast Yarrowia lipolytica as a PP2A. The aim of the present work was to seek the presence of one protein phosphatase excreted in the exocellular medium and to study its activity during yeast growth in media supplemented or not supplemented with inorganic phosphate. Protein phosphatase was purified and activity was assayed by following the dephosphorylation of three substrates, [32P]casein, phosphotyrosine and a synthetic tyrosine-phosphorylated peptide. Phosphatase activity recovered in the medium after 25 h culture was greatly enhanced by Pi-deficiency. After several purification steps, the enzyme preparation presents an apparent electrophoretic homogeneity on SDS-PAGE with associated phosphoseryl/threonyl and phosphotyrosyl activities. The kinetic properties exclude contamination by a copurified protein and it is concluded that the two activities are carried by the same single proteic species. It was characterized by gel filtration as a 33 kDa protein with one single subunit demonstrated by SDS-PAGE. An absolute requirement for reducing-agents is observed suggesting that the enzyme contains at least one essential reactive cysteinyl residue. Optimum pH value is 6.1, apparent K(m) for phosphotyrosine was calculated to be 760 microM and Hill coefficient 3.2 indicating a rather high cooperativity. These results showed that the involvement of alkaline and/or acid phosphatase was unlikely. In conclusion, a protein phosphatase distinct from endocellular PP2A is secreted by Yarrowia lipolytica and characterized as a phosphotyrosine protein phosphatase with associated phosphoseryl/threonyl activity.     

Intersymbol interference due to linear and nonlinear distortion

The paper provides a recursion model for the calculation of the probability density function (pdf) of intersymbol interference (ISI) which is caused by the combined effect of linear channel dispersion and of nonlinear distortion. The nonlinearity introduces statistical interdependencies between the interfering symbols and these dependencies are implicitly taken into account in a trellis-structured recursion rule. The results were verified by time consuming Monte Carlo simulation and show, e.g., that the nonlinear characteristic of a high power amplifier (HPA) reduces in some cases the error probability caused by the linear dispersion. Surprisingly, the ISI due to the nonlinear amplifier is increased in the case of offset modulation     

High-temperature chemical heat pump based on reversible catalytic reactions of cyclohexane-dehydrogenation/benzene-hydrogenation: Comparison of the potentialities of different flow diagrams

The authors compare various flow diagrams for high temperature chemical heat pumps (HTCHP) based on the reversible cyclohexane-dehydrogenation/benzene-hydrogenation reactions. A new technological flow diagram for HTCHP is suggested. The peculiarity of this diagram is a multipurpose use of hydrogen-permeable membranes. A comparative thermodynamic analysis of the flow diagrams under consideration is undertaken in order to examine the influence of various factors on the heat efficiency and coefficient of performance of the heat pump. It is shown that the use of the hydrogen-permeable membranes in principle allows one to improve the performance of the HTCHPs and to extend the field of their application in comparison with the HTCHPs based on the flow diagrams suggested earlier.