Crystallization and gelation of poly(vinylidene fluoride) in organic solvents

Poly(vinylidene fluoride) (PVdF) converts easily to thermally reversible gel at room temperature in aliphatic ketones or cyclic ketones such as 3-pentanone, 3-hexanone, cyclohexanone, and -butyrolactone, etc. Gelation of PVdF in these ketones took place through crystallization of polymers from solution. The crystallization process was investigated in detail by Fourier transform infrared (FTIR) measurements. The FTIR spectra were recorded continuously at room temperature until the solution converted to gel. It was suggested from spectral data that polymer chains packed together (i.e., crystallization took place) into the TTTGTTTG¯ conformation in the case of PVdF/γ-butyrolactone solution, followed immediately by gelation. On the other hand, crystallization occurred into the TGTG¯ conformation in the case of other ketones and gelation immediately took place. Melting temperatures of PVdF gels thus prepared from these solvents were measured. showed a solvent dependence. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:1517–1524, 1997     

-linked oligosaccharide in MSP-1 and its implication for scallop calcification

We speculated the structure of the N-linked oligosaccharides enzymatically released from the organic matrix (OM) component in the foliated layer of Patinopecten yessoensis. The 80 kDa component of the soluble OM was detected by lectin blotting and was identified as MSP-1 using liquid chromatography/mass spectrometry (LC/MS/MS). LC/MS/MS analysis of the N-glycan liberated from MSP-1 detected a hybrid-type N-glycan, which contained sulfite and sialic acid at its terminus based on the characteristic Y ions. The data strongly imply that MSP-1, a sulfated OM glycoprotein, participates in molluscan biomineralization by creating a favorable environment for calcium ion uptake through sulfite acid and sialic acid. Further analyses of oligosaccharides linked to the OM components in wide variety of species and shell microstructures may definitely contribute in elucidation of molluscan biomineralization at the molecular level.     

Exosome Degeneration in Mesenchymal Stem Cells Derived from Patients with Type 1 Diabetes Mellitus

Type 1 diabetes mellitus is characterized by the destruction of pancreatic β-cells and requires the regeneration of these destroyed pancreatic β-cells for radical treatment. The degeneration of organelles in stem cells compromises stem cell quality; however, organelles in the mesenchymal stem cells of patients with type 1 diabetes mellitus have not been characterized previously. In this study, we use transmission electron microscopy to evaluate the degeneration of organelles in adipose-derived stem cells of patients with type 1 diabetes mellitus (T1DM ADSCs). Compared to adipose-derived stem cells from healthy humans, T1DM ADSCs degenerate differently, characterized by prominent enlarged spherical vesicles. The exosomes of T1DM ADSCs are found to be enlarged, reduced in number, and increased in the percentage of those positive for tetraspanin CD9. The findings of this study provide insight into the characteristics of stem cells in patients with type 1 diabetes mellitus.     

Fabrication of uniform ZrC coating layer for the coated fuel particle of the very high temperature reactor

Fuel for the very high temperature reactor is required to be used under severer irradiation conditions and higher operational reactor temperatures than those of present high temperature gas cooled reactors. Japan Atomic Energy Agency has developed zirconium carbide (ZrC)-coated fuel particles previously in laboratory scale which are expected to maintain their integrity at higher temperatures and burnup conditions than conventional silicon carbide-coated fuel particles. As one of the important R&D items, ZrC coating process development has been started in the year 2004 to determine the coating conditions to fabricate uniform structure of ZrC layers by using a new large-scale coater up to 0.2 kg batch. It was thought that excess carbon formed in the ZrC layer under the oscillation of coating temperature would cause non-uniformity of the ZrC layer. Finally, uniform ZrC coating layer has been fabricated successfully by adjusting the time constant of the coater and keeping the coating temperature at around 1400 °C.     

Social behavior and off-target verbosity in elderly people.

This study investigated social behavior in older adults with varying levels of off-target verbosity (OTV). After screening 455 adults in Phase 1, 198 individuals were selected to participate in both a get-acquainted conversation and an experimental cues situation and to complete social and cognitive measures. Higher OTV participants had lower cognitive inhibitory scores, talked more, were less interested in their partners, and focused more on themselves. Their conversational partners were less satisfied. Age and cognitive functioning were not related to OTV scores or conversational style for low and mid-range participants. Although high-OTV individuals talked less when exposed to social cues signalling boredom, they spoke more relative to other participants. Self-reported social behavior had little relation with OTV and conversational style, but higher OTV individuals were less accurate in judging videotaped social interactions. Gender differences in conversational behavior are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Production of equol from daidzein by gram-positive rod-shaped bacterium isolated from rat intestine

Isoflavones (mainly daidzein and genistin) belong to the flavonoid group of compounds and are classified as phytoestrogens. In the intestine, daidzin is converted to daidzein by beta-glucosidase, and then daidzein is converted to O-desmethylangolensin (O-DMA) or equol via dihydrodaidzein by enzymes of intestinal bacteria. We isolated, for the first time, an anaerobic gram-positive rod-shaped strain capable of producing equol from daidzein. Its 16S rDNA gene sequence (1428 bp) showed 99% similarity with that of the human intestinal bacterium SNU-Julong 732 (AY310748) and 93% similarity with that of Eggerthella lenta ATCC 25559(T) (AF292375). This strain converted daidzein to equol via dihydrodaidzein in an equol-assay medium anaerobically. The addition of butyric acid and arginine increased the conversion ratio of daidzein to equol 4.7- and 4.5-fold, respectively.     

Perforated Hydrogels Consisting of Cholesterol-Bearing Pullulan (CHP) Nanogels: A Newly Designed Scaffold for Bone Regeneration Induced by RANKL-Binding Peptides and BMP-2

The receptor activator of NF-κB ligand (RANKL)-binding peptide, OP3-4, is known to stimulate bone morphogenetic protein (BMP)-2-induced bone formation, but peptides tend to aggregate and lose their bioactivity. Cholesterol-bearing pullulan (CHP) nanogel scaffold has been shown to prevent aggregation of peptides and to allow their sustained release and activity; however, the appropriate design of CHP nanogels to conduct local bone formation needs to be developed. In the present study, we investigated the osteoconductive capacity of a newly synthesized CHP nanogel, CHPA using OP3-4 and BMP-2. We also clarified the difference between perforated and nonperforated CHPA impregnated with the two signaling molecules. Thirty-six, five-week-old male BALB/c mice were used for the calvarial defect model. The mice were euthanized at 6 weeks postoperatively. A higher cortical bone mineral content and bone formation rate were observed in the perforated scaffold in comparison to the nonperforated scaffold, especially in the OP3-4/BMP-2 combination group. The degradation rate of scaffold material in the perforated OP3-4/BMP-2 combination group was lower than that in the nonperforated group. These data suggest that perforated CHPA nanogel could lead to local bone formation induced by OP3-4 and BMP–2 and clarified the appropriate degradation rate for inducing local bone formation when CHPA nanogels are designed to be perforated.     

Influences of the ZrC coating process and heat treatment on ZrC-coated kernels used as fuel in Pu-burner high temperature gas-cooled reactor in Japan

ABSTRACT

The concept of Pu-burner high temperature gas-cooled reactor (HTGR) has been proposed to more safely reduce the amount of recovered Pu. In the Pu-burner HTGR concept, coated fuel particles with ZrC-coated yttria-stabilized zirconia containing PuO₂ (PuO₂-YSZ) kernels are employed for very high burn-up and high nuclear proliferation resistance. The role of ZrC layer is that of oxygen getter. CeO₂-YSZ kernels were fabricated to simulate the PuO₂-YSZ kernel and coated with a ZrC layer. In this study, we clarified that both Ce-rich grains and Zr-rich grains were densely distributed in surface regions of the as-fabricated CeO₂-YSZ kernel. However, we have already clarified that the surface region of the CeO₂-YSZ kernel coated with a ZrC layer was porous and mainly consisted of Zr-rich grains. These experimental results confirmed that Ce-rich grains were selectively corroded during the ZrC coating process. Then, the chemical stability of Zr-rich grains would be higher than that of Pu-rich grains. Thus, it would be more difficult to extract Pu from PuO₂-YSZ kernels (in which almost all grains are Zr-rich) than from PuO₂-YSZ kernels (in which many Pu-rich grains are included). Influences of the sintering of fuel compact on the microstructure of the ZrC-coated CeO₂-YSZ kernel is also reported.