Fabrication development for high-level nuclear waste containers for the tuff repository; Phase 1 final report

This final report completes Phase 1 of an engineering study of potential manufacturing processes for the fabrication of containers for the long-term storage of nuclear waste. An extensive literature and industry review was conducted to identify and characterize various processes. A technical specification was prepared using the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (ASME BPVC) to develop the requirements. A complex weighting and evaluation system was devised as a preliminary method to assess the processes. The system takes into account the likelihood and severity of each possible failure mechanism in service and the effects of various processes on the microstructural features. It is concluded that an integral, seamless lower unit of the container made by back extrusion has potential performance advantages but is also very high in cost. A welded construction offers lower cost and may be adequate for the application. Recommendations are made for the processes to be further evaluated in the next phase when mock-up trials will be conducted to address key concerns with various processes and materials before selecting a primary manufacturing process. 43 refs., 26 figs., 34 tabs

The Development and Subsequent Elimination of Aberrant Peripheral Axon Projections in Semaphorin3A Null Mutant Mice

AbstractSemaphorin3A (previously known as Semaphorin III, Semaphorin D, or collapsin-1) is a member of the semaphorin gene family, many of which have been shown to guide axons during nervous system development. Semaphorin3A has been demonstrated to be a diffusible chemorepulsive molecule for axons of selected neuronal populations in vitro. Analysis of embryogenesis in two independent lines of Semaphorin3A knockout mice support the hypothesis that this molecule is an important guidance signal for neurons of the peripheral nervous system (M. Taniguchi et al., 1997, Neuron 19, 519–530; E. Ulupinar et al., 1999, Mol. Cell. Neurosci. 13, 281–292). Surprisingly, newborn Semaphorin3A null mutant mice exhibit no significant abnormalities (O. Behar et al., 1996, Nature 383, 525–528). In this study we have tested the hypothesis that guidance abnormalities that occurred during early stages of Semaphorin3A null mice development are corrected later in development. We have found that the extensive abnormalities formed during early developmental stages in the peripheral nervous system are largely eliminated by embryonic day 15.5. We demonstrate further that at least in one distinct anatomical location these abnormalities are mainly the result of aberrant projections. In conclusion, these findings suggest the existence of correction mechanisms that eliminate most sensory axon pathfinding errors early in development

Identification and Characterization of a Novel Multipotent Sub-Population of Sca-1+ Cardiac Progenitor Cells for Myocardial Regeneration

The cardiac stem/progenitor cells from adult mice were seeded at low density in serum-free medium. The colonies thus obtained were expanded separately and assessed for expression of stem cell antigen-1 (Sca-1). Two colonies each with high Sca-1 (CSH1; 95.9%; CSH2; 90.6%) and low Sca-1 (CSL1; 37.1%; CSL2; 17.4%) expressing cells were selected for further studies. Sca-1⁺ cells (98.4%) isolated using Magnetic Cell Sorting System (MACS) from the hearts were used as a control. Although the selected populations were similar in surface marker expression (low in c-kit, CD45, CD34, CD31 and high in CD29), these cells exhibited diverse differentiation potential. Unlike CSH1, CSH2 expressed Nanog, TERT, Bcrp1, Nestin, Musashi1 and Isl-1, and also showed differentiation into osteogenic, chondrogenic, smooth muscle, endothelial and cardiac lineages. MACS sorted cells exhibited similar tendency albeit with relatively weaker differentiation potential. Transplantation of CSH2 cells into infarcted heart showed attenuated infarction size, significantly preserved left ventricular function and anterior wall thickness, and increased capillary density. We also observed direct differentiation of transplanted cells into endothelium and cardiomyocytes.The cardiac stem/progenitor cells isolated by a combined clonal selection and surface marker approach possessed multiple stem cell features important for cardiac regeneration

Temporal Controls of the Asymmetric Cell Division Cycle in Caulobacter crescentus

The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA. The regulatory network is cast into a quantitative computational model to investigate in a systematic fashion how these three proteins control the relevant genetic, biochemical and physiological properties of proliferating bacteria. Different controls for both swarmer and stalked cell cycles are represented in the mathematical scheme. The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions. Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella)

Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

The influence of agglomeration in fluidized bed on particles shape of choosen food powders

Celem pracy było zbadanie wpływu aglomeracji nawilżeniowej wieloskładnikowych mieszanin spożywczych na kształt cząstek otrzymywanych aglomeratów. Zakres badań obejmował analizę wpływu metody aglomeracji nawilżeniowej na średnie wartości współczynników związanych z kształtem cząstek: powierzchni projekcyjnej, obwodu projekcji, średnicy projekcyjnej, objętości, współczynnika wydłużenia oraz współczynnika kształtu. Aglomeracja nawilżeniowa wpływa na średnie wielkości badanych współczynników mieszanin proszków spożywczych. Zakres wpływu uzależniony jest od metody aglomeracji oraz składu surowcowego badanych mieszanin. Mechanicznie tworzenie aglomeratów sprzyja powstawaniu większych cząstek o regularnym kształcie.The aim of work was examining the influence of agglomeration of multiple food mixtures on shape of agglometated particles. The range of investigations hugged the analysis of influence of type of mixing during wett agglomeration on average values of coefficients connected with shape of particles: projection surface, projection perimeter, projection dimeter, volume of particles, elongation coefficient and circularity coefficient. The wett agglomeration influences on average volues of investigated coefficients. The range of influence is dependent on method of agglomeration as well as composition of the raw material. Creating agglomerates mechanically favours formation larger particles with more regular shape

Adsorption kinetics of water vapour by agglomerates of selected mixtures of food powders

Badano kinetykę adsorpcji pary wodnej przez mieszaniny proszków spożywczych i ich aglomeraty otrzymane w pneumatycznie generowanym złożu fluidalnym (metoda fluidalna) oraz w mechanicznie generowanym złożu fluidalnym (metoda mechaniczna). Mieszaniny sporządzono z produktów w proszku, takich, jakich jak serwatka, izolat białek serwatkowych, izolat sojowy, glukoza oraz tłuszcz palmowy płynny i sproszkowany. Aglomeracja badanych mieszanin spowodowała obniżenie adsorpcji pary wodnej w porównaniu z mieszaninami nieaglomerowanymi. Aglomeraty otrzymane metodą mechaniczną charakteryzowały się większą zdolnością chłonięcia wody w porównaniu z aglomeratami uzyskanymi metodą fluidalną. Obecność sproszkowanego tłuszczu w aglomeracie otrzymanym metodą mechaniczną spowodowała obniżenie zdolności chłonięcia wody w porównaniu z metodą fluidalną.The research dealt with adsorption kinetics of water vapour by mixtures of food powders and their agglomerates obtained in pneumatically generated fluid bed (fluid method) and in mechanically generated fluid bed (mechanical method). The mixtures were prepared from powdered products such as whey, whey protein isolates, soy isolate, glucose, as well as fluid and powdered palm oil. Agglomeration of the examined mixtures resulted in reduction of water vapour adsorption, compared to non-agglomerated mixtures. The agglomerates obtained by using the mechanical method were characterized by greater capacity for water absorption when compared to the agglomerates obtained by the fluid method. The presence of powdered fat in the agglomerate obtained by using the mechanical method resulted in the decreased capacity for water absorption in comparison to the fluid method