Distribution and localization of galectin purified from Rana catesbeiana oocytes

Galectins are a family of lectins that recognize beta-D-galactosides independently of calcium ions, and are widely distributed in animals. To characterize a galectin previously purified from oocytes of Rana catesbeiana (American bullfrog), we studied its distribution and localization in several tissues from this frog. Hemagglutination assay and western blotting showed that this lectin is present in many tissues including the liver, skin, kidney, skeletal muscle, and sciatic nerve, but is particularly concentrated in the ovary. Light microscopic immunohistochemistry showed that this lectin is localized in such places as cell-cell junctions, basement membranes, extracellular matrix, or secretory substances in several organs, indicating that this galectin is mainly distributed extracellularly. However, in the ovary, light microscopy showed that this lectin is present in or associated with the yolk platelet. Electron microscopy further revealed that it is localized in the periphery of the yolk platelet (the yolk plasm), but not in the cortical granule. These results indicate that Rana oocytes contain abundant galectin in their yolk platelets in contrast to Xenopus laevis oocytes, which have been found not to contain galectins but other classes of lectins in their yolk platelets and cortical granules.     

Development of Mo(Si,Al)<Subscript>2</Subscript>-base oxidation-resistant coating on Nb-base structural materials

Mo(Si,Al)₂-base oxidation-resistant coatings for Nb-base structural materials have been studied. The coating is composed of a Mo(Si,Al)₂-base Al reservoir and Al₂O₃ interlayer to suppress interface reactions between the Al reservoir and the substrate. To develop a suitable Al-reservoir material, some Mo(Si_0.6,Al_0.4)₂-HfB₂ composites were prepared. Their oxidation resistance and coefficients of thermal expansion were investigated, in addition to their chemical reactivity with the Nb substrate at high temperatures. As a result, Mo(Si_0.6,Al_0.4)₂-20 vol pct HfB₂ was selected as one of the satisfactory Al reservoirs. The introduction of a stable Al₂O₃ interlayer was attempted using a novel powder metallurgical process to overlay the Nb substrates with the Al reservoir, where the Nb substrates were subjected to a slight surface oxidation prior to the coating process. The Nb specimens, which are thoroughly coated with the Al reservoir and Al₂O₃ interlayer, can be successfully fabricated by this method. The coated Nb specimens are not damaged at all after prolonged exposure in flowing Ar-20 pct O₂ at 1673 K for 120 hours. Furthermore, the Al₂O₃ interlayer is very effective and no reactions occur at the interface. Thus, this Mo(Si,Al)₂-base oxidation-resistant coating is applicable to Nb. The utility of the coating system is also confirmed for a Nb_SS/Nb₅Si₃ composite. This article is based on a presentation made in the symposium entitled “Beyond Nickel-Base Superalloys,” which took place March 14–18, 2004, at the TMS Spring meeting in Charlotte, NC, under the auspices of the SMD-Corrosion and Environmental Effects Committee, the SMD-High Temperature Alloys Committee, the SMD-Mechanical Behavior of Materials Committee, and the SMD-Refractory Metals Committee.     

Effects of boron doping in low- and high-surface-area carbon powders

Two distinctive carbon materials (Saran char and SP-1 graphite) were doped with B at different loading to clarify the intrinsic effect of substitutional B on carbon reactivity. The carbon precursors would be affected in different style by substitutional B due to different important properties (crystallinity and surface area). The B retentivity depended on the nature of B dopant and carbon substrate; a less ordered carbon has higher B loading than its counterpart. Graphitization was enhanced by substitutional B, as expected. Furthermore, the B incorporation was still beneficial for SP-1 although it already had high crystallinity. An interesting behavior was noticed; the increase in L_a was greater than L_c. The intrinsic effect of substitutional B in carbon oxidation was proved to be a catalytic one. Unlike highly ordered SP-1 graphite, Saran char showed both a catalytic effect at low B loading and low conversion, and an inhibiting effect at high B loading and high conversion. The inductive effect was proposed to explain this catalytic effect on different crystallite size. Different sizes of carbon clusters were calculated by Gaussian 98W; the extent of the effect of substitutional B did get smaller to the carbon in bigger size of carbon cluster.     

A novel mutant allele of Schizosaccharomyces pombe rad26 defective in monitoring S-phase progression to prevent premature mitosis

A semipermissive growth condition was defined for a Schizosaccharomyces pombe strain carrying a thermosensitive allele of DNA polymerase delta (pol delta ts03). Under this condition, DNA polymerase delta is semidisabled and causes a delay in S-phase progression. Using a genetic strategy, we have isolated a panel of mutants that enter premature mitosis when DNA replication is incomplete but which are not defective for arrest in G2/M following DNA damage. We characterized the aya14 mutant, which enters premature mitosis when S phase is arrested by genetic or chemical means. However, this mutant is sensitive to neither UV nor gamma irradiation. Two genomic clones, rad26+ and cds1+, were found to suppress the hydroxyurea sensitivity of the aya14 mutant. Genetic analysis indicates that aya14 is a novel allele of the cell cycle checkpoint gene rad26+, which we have named rad26.a14. cds1+ is a suppressor which suppresses the S-phase feedback control defect of rad26.a14 when S phase is inhibited by either hydroxyurea or cdc22, but it does not suppress the defect when S phase is arrested by a mutant DNA polymerase. Analyses of rad26.a14 in a variety of cdc mutant backgrounds indicate that strains containing rad26.a14 bypass S-phase arrest but not G1 or late S/G2 arrest. A model of how Rad26 monitors S-phase progression to maintain the dependency of cell cycle events and coordinates with other rad/hus checkpoint gene products in responding to radiation damage is proposed.     

Heterogeneous Multi-Core Architecture That Enables 54x AAC-LC Stereo Encoding

This paper describes a heterogeneous multi-core processor (HMCP) architecture that integrates general-purpose processors (CPUs) and accelerators (ACCs) to achieve exceptional performance as well as low-power consumption for the SoCs of embedded systems. The memory architectures of CPUs and ACCs were unified to improve programming and compiling efficiency. Advanced audio codec-low complexity (AAC-LC) stereo audio encoding was parallelized on a heterogeneous multi-core having homogeneous processor cores and dynamically reconfigurable processor (DRP) ACC cores in a preliminary evaluation of the HMCP architecture. The performance evaluation revealed that 54times AAC encoding was achieved on the chip with two CPUs at 600 MHz and two DRPs at 300 MHz, which achieved encoding of an entire CD within 1- 2 min.     

Reactive carbon black having isocyanate or acyl azide group

Summary Introduction of isocyanate (NCO) group onto carbon black surface was achieved by the treatment of carbon black with toluene-2,4-diisocyanate. In addition, carbon black having acyl azide (CON₃) group, a precursor of NCO group, was prepared by the reaction of COCl or COOCOOC₂H₅ group on carbon black with NaN₃. The CON₃ group on carbon black was relatively stable at below 20°C but readily decomposed to NCO group by heating (Curtius rearrangement). By the reation of NCO group on carbon black with hydroxyl group of polymers, such as polypropylene glycol, polyethylene glycol, and polyvinyl alcohol, these polymers were found to be grafted onto carbon black.     

Characterization of electrode/electrolyte interface for lithium batteries using in situ synchrotron X-ray reflectometry—A new experimental technique for LiCoO2 model electrode

A new experimental technique was developed for detecting structure changes at electrode/electrolyte interface of lithium cell using X-ray reflectometry and two-dimensional model electrodes with a restricted lattice-plane. The electrodes were constructed with an epitaxial film of LiCoO₂ synthesized by pulsed laser deposition method. The orientation of the epitaxial film depends on the substrate plane; the 2D layer of LiCoO₂ is parallel to the SrTiO₃ (1 1 1) substrate (_(0 0 3)LiCoO₂//_(1 1 1)SrTiO₃)$({(003)}_{\text{LiCo}{\text{O}}_2}//{(111)}_{\text{SrTi}{\text{O}}_3})$, while the 2D layer is perpendicular to the SrTiO₃ (1 1 0) substrate (_(1 1 0)LiCoO₂//_(1 1 0)SrTiO₃)$({(110)}_{\text{LiCo}{\text{O}}_2}//{(110)}_{\text{SrTi}{\text{O}}_3})$. The anisotropic properties were confirmed by electrochemical measurements. Ex situ X-ray reflectivity measurements indicated that the impurity layer existed on the as-grown LiCoO₂ was dissolved and a new SEI layer with lower density was formed after soaking into the electrolyte. In situ X-ray reflectivity measurements indicated that the surface roughness of the intercalation (1 1 0) plane increased with applying voltages, while no significant changes in surface morphology were observed for the intercalation non-active (0 0 3) plane during the pristine stage of the charge–discharge process.     

Assimilative and co-metabolic degradation of chloral hydrate by bacteria and their bioremediation potential

Although the bacterial degradation of chloral hydrate (CH) has been recognized for several decades, its degradation pathway by assimilation has not been demonstrated. In this paper, we report the isolation of the LF54 bacterial strain, which utilizes CH as its sole carbon and energy source. LF54 converted CH into trichloroethanol (TCAol), which was dehalogenated to dichloroethanol (DCAol), and CO(2) was detected as the end product. Another strain that we isolated, RS20, co-metabolized CH into TCAol. Our 16S rRNA gene sequencing and taxonomic analyses revealed that the LF54 and RS20 strains belong to the Pseudomonas and Arthrobacter genera, respectively. When the two strains were inoculated into soil microcosms, both degraded 0.3mM CH to undetectable levels (<0.01mM) within 5days. These results suggest that LF54 and RS20 could be used in the bioremediation of CH-contaminated environments.