Bone formation following implantation of fibrous calcium compounds (β−Ca(PO3)2, CaCO3(aragonite)) into bone marrow

Bone formation around three types of fibrous calcium-containing crystals has been examined histologically using rats. The implanted materials are (i) calcium metaphosphate (–Ca(PO₃)₂) fibers having aspect ratios of 15–80 with 2–20 m in diameter, (ii) –Ca(PO₃)₂) fibers surface-modified using dilute NaOH and (iii) calcium carbonate (CaCO₃; aragonite phase) whiskers having aspect ratios of 15–40 with 0.5–3 m in diameter. –Ca(PO₃)₂ fibers show a mechanically high strength with a low modulus of elasticity, and the surface-modified fibers have a thin layer consisting of a calcium orthophosphate phase. CaCO₃ whiskers were used for comparison reasons. The materials were implanted for 4, 8, and 12 weeks into bone defects created in the bone marrow of rat tibiae. Cancellous bone formation was observed around –Ca(PO₃)₂ fibers, the surface-modified fibers and CaCO₃ whiskers after implantation for 12, 4 and 4 weeks, respectively. CaCO₃ whiskers were scarcely observed after 12 weeks for resorbing. The calcium phosphate fibrous materials show combined advantages of mechanically high strength for toughening a matrix phase and biological activities; thus, these materials may prove to be useful for novel applications in the biomedical field.     

Development of the package-reactor (2) -core characteristics-

A new small reactor concept named the Package-Reactor has been jointly developed by Hitachi, Ltd. and Mitsubishi Heavy Industries, Ltd. The reactor technology was built from that of conventional LWRs. The reactor core consists of 12 cassettes containing fuel rods with a similar design to that of PWR fuel rods. Each cassette has about a 0.4 m outer diameter and they are fixed with about 0.5 m pitch to each other in the atmospheric pressure condition. A tube-type control cluster was developed. It can decrease the rise of reactivity for the one-rod-stuck condition. An advanced cassette design was studied in which the down-comer is placed at the center of the fuel region. This concept, which improves neutron economics and the cold shutdown margin, will increase the marketability of the Package-Reactor. An operation period of more than 8 years can be achieved with UO₂ fuel enrichment of 5.0wt%.     

Apoptosis induction of POS canine osteosarcoma cells by vitamin D and retinoids

Vitamin D3: 1-alpha, 25(OH)2D3 (calcitriol), 22-oxa-1,25(OH)2D3 (OCT), cholecalciferol (vitamin D3), and retinoids: all-trans retinoic acid (ATRA) and 9-cis retinoic acid, induced morphological changes in POS canine osteosarcoma cells into elongated, spindle or fibroblast like-shaped cells, and apoptotic like cell death characterized by cell shrinkage, condensation and margination of the nucleus for all drugs at 10(-6)M-10(-9)M after 72 to 120 hr culture. Apoptosis as shown by DNA laddering was induced at 48 hr by all drugs at 10(-6)M, 10(-7)M at 96 hr, 10(-8)M and 10(-9)M at 120 hr respectively. These vitamins are suggested to adjunct antineoplastic agents in canine osteosarcoma therapy by induction of apoptosis.     

Titanium powder production by TiCl4 gas injection into magnesium through molten salts

A process to produce titanium powder continuously is proposed and its applicability is examined experimentally. The method is based on the chemical reaction in the conventional Kroll reduction process; however, TiCl₄ gas is injected into molten salt on which a molten magnesium layer is floated as the reductant. Bubbles of gaseous TiCl₄ can be reacted at the lower surface of the liquid Mg layer, while TiCl₄ gas reacts on the upper surface in the Kroll process. The fine Ti particles produced in this study were well separated from magnesium and could be recovered from the bottom of the molten salts. The particles were small and fine enough for use in powder metallurgy, while congregated lumps of about 20 μm in size are obtained by the Kroll process. The composition of molten salts and an operation temperature above 1073 K did not affect the morphology of the Ti particles, if suitable material for the reaction vessel was chosen.     

Biodegradable organic acid-crosslinked alkali-treated gelatins with anti-thrombogenic and endothelialization properties

Gelatins were crosslinked with organic acids and treated with alkali to impart to them endothelialization and anti-thrombogenic properties. These matrices were characterized by biochemical and physicochemical techniques. The amounts of residual amino groups in the matrices decreased with increasing crosslinker concentration. The matrices with the highest crosslinking densities showed excellent endothelial cell adhesion and proliferation. In addition, the adhesion of platelets and formation of fibrin networks on the matrices were suppressed with increasing crosslinker concentration. The matrices also exhibited excellent biodegradability, and the degradation rate decreased with increasing crosslinking density. All the organic acid-crosslinked alkali-treated gelatins showed excellent anti-thrombogenic and endothelialization properties, superior to those of glutaraldehyde-crosslinked alkali-treated gelatins.     

Preliminary study on the thorium-loaded accelerator-driven system with 100 MeV protons at the Kyoto University Critical Assembly

At the Kyoto University Critical Assembly (KUCA), spallation neutrons generated by high-energy proton beams are injected into the thorium-loaded systems on March 2010. By combining the Fixed Field Alternating Gradient (FFAG) accelerator with the thorium-loaded system at KUCA, a series of the ADS experiments is carried out under conditions whereby the spallation neutrons are generated at a tungsten target by 100 MeV protons at an intensity of 30 pA. Prompt neutron behavior in the time evolution is observed and thorium fission reactions are attained through the experiments and calculations, respectively. And the effects of neutron leakage and spectrum softening are experimentally observed through the neutron multiplication and reaction rate analyses. From the experimental and numerical analyses, in the future, experimental conditions need to be improved to attain further neutron multiplication using the variation of fuels (thorium, highly-enriched and natural uranium) and moderators (graphite, polyethylene, aluminum and beryllium).     

Molecular composition of the 16S toxin produced by a Clostridium botulinum type D strain, 1873

The 16S toxin was purified from a Clostridium botulinum type D strain 1873 (D-1873). Furthermore, the entire nucleotide sequences of the genes coding for the 16S toxin were determined. It became clear that the purified D-1873 16S toxin consists of neurotoxin, nontoxic nonhemagglutinin (NTNH), and hemagglutinin (HA), and that HA consists of four subcomponents, HA1, HA2, HA3a, and HA3b, the same as type D strain CB16 (D-CB16) 16S toxin. The nucleotide sequences of the nontoxic components of these two strains were also found to be identical except for several bases. However, the culture supernatant and the purified 16S toxin of D-1873 showed little HA activity, unlike D-CB16, though the fractions successively eluted after the D-1873 16S toxin peak from an SP-Toyopearl 650S column showed a low level of HA activity. The main difference between D-1873 and D-CB16 HA molecules was the mobility of the HA1 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Therefore it was presumed that the loss of HA activity of D-1873 16S toxin might be caused by the differences of processing HA after the translation.