Industrial diversity and metropolitan unemployment rate

The main goal of our study is to evaluate whether or not industrial diversity helps reduce the frictional unemployment rate of a metropolitan area. We used a data set from Japan’s 118 metropolitan areas. Our analysis shows that although industrial diversity might reduce the frictional unemployment rate of a metropolitan area, its effect is not statistically significant in our model. Second, the location quotient for industries, considered to be related to types of unemployment other than frictional, has a stronger impact on unemployment rate than industrial diversity does. In particular, it was found that the location quotients for both the manufacturing and the construction industry have a negative relationship with the unemployment rate of a metropolitan area. We also discovered that the higher the percentage of graduates of post-secondary institutions there are in a metropolitan area, the lower its unemployment rate will be.

Dosimetric properties of UV irradiated calcium co-doped borate glass-ceramic

The thermoluminescence (TL) response of Dy and Li doped 20CaB₄O₇-80CaB₂O₄ (wt%) glass-ceramic irradiated with ultraviolet (UV) radiation was studied. In order to act as TL activator ions, the Dy and Li ions were included in the matrix during the melting process to increase its TL efficiency. A single crystalline CaB₂O₄ phase was present in the glass-ceramic as determined by X-ray diffraction (XRD). The glass-ceramic 20CaB₄O₇-80CaB₂O₄:Dy,Li wt% (named 20CBO7:Dy,Li) is a newly prepared TL material. Its thermoluminescent dosimetric characteristics have shown a linear response under UV radiation exposure and a good TL signal reproducibility, thus proving to be a promising material for using as an ultraviolet radiation dosimeter.     

Poly-γ-glutamate-based Materials for Multiple Infection Prophylaxis Possessing Versatile Coating Performance

Poly-γ-glutamate (PGA) possesses a nylon-like backbone and polyacrylate-like carboxyl groups, and shows an extraordinary solubility in water. In this study, the effective synthesis and structural analysis of some water-insoluble PGA ion-complexes (PGAICs) using cationic surfactants, hexadecylpyridinium (HDP), dodecylpyridinium, benzalkonium and benzetonium, were examined. We demonstrated their spontaneous coating performance to the surfaces of different materials (i.e., plastics, metals, and ceramics) as potent anti-staphylococcal and anti-Candida agents. The tests against Staphylococcus aureus revealed that, regardless of a variety of materials, PGAICs maintained surface antimicrobial activity, even after the water-soaking treatment, whereas those against Candida albicans indicated that, among PGAICs, PGA/HDP complex is most useful as an anti-fungal agent because of its coating stability. Moreover, the log reduction values against Influenza A and B viruses of PGA/HDP-coated surfaces were estimated to be 5.4 and 3.2, respectively, suggesting that it can be dramatically suppressed the infection of influenza. This is to our knowledge the first observation of PGA-based antiviral coatings.     

Construction of an autonomously replicating plasmid in n-alkane-assimilating yeast, Candida tropicalis

A transformation system using the autonomously replicating plasmid in the n-alkane-assimilating and asporogenic diploid yeast, Candida tropicalis, was developed. For the cloning of a DNA fragment containing a potential autonomously replicating sequence (ARS) from the genomic DNA of C. tropicalis, the ura3 mutant obtained using ethylmethane sulfonate as the host and the URA3 gene amplified by PCR using the C. tropicalis genomic DNA as a selectable marker were prepared. Comparison of ARSs among yeasts revealed that the consensus sequence found in S. cerevisiae was also present in C. tropicalis. The autonomously replicating plasmid containing the putative ARS as the shuttle vector, capable of replicating in both E. coli and C. tropicalis, was first constructed. The transformation system using this plasmid, in addition to the integrative transformation system, will be applicable to genetic studies of C. tropicalis.     

Radiation vulcanization of natural rubber latex with polyfunctional monomers

Natural rubber latex was irradiated with γ-rays from Co-60 in the presence of polyfunctional monomers to accelerate crosslinking of rubber molecules. Hydrophobic monomers were more effective in accelerating the vulcanization than were hydrophilic monomers. This was ascribed to high solubility of hydrophobic monomers in rubber particles. Among the hydrophobic monomers, neopentylglycol dimethacrylate (NPG) exhibited the highest efficiency in accelerating the vulcanization. Advantages of using NPG are (1) high colloidal stability of the irradiated latex and (2) high thermal stability of dried rubber film.     

Dispersion of fillers and the electrical conductivity of polymer blends filled with carbon black

Dispersion state of carbon black(CB) was studied in polymer blends which are incompatible with each other. It was found that CB distributes unevenly in each component of the polymer blend. There are two types of distribution. (1) One is almost predominantly distributed in one phase of the blend matrix, and in this phase fillers are relatively homogeneously distributed in the same manner as a single polymer composite. (2) In the second, the filler distribution concentrates at interface of two polymers. As long as the viscosities of two polymers are comparable, interfacial energy is the main factor determining uneven distribution of fillers in polymer blend matrices. This heterogeneous dispersion of conductive fillers has much effect on the electrical conductivity of CB filled polymer blends. The electrical conductivity of CB filled polymer blends is determined by two factors. One is concentration of CB in the filler rich phase and the other is phase continuity of this phase. These double percolations affect conductivity of conductive particle filled polymer blends.     

Radiation grafting of hydrophilic monomers onto poly(4-methylpentene-1), II. Grafting of long chain monomers and physical properties of the grafted films

Radiation grafting of 2-hydroxyethyl methacrylate (HEMA) and methoxytetraethyleneglycol methacrylate (M4G) on low crystallinity poly(4-methylpentene-1) (TPX) has been investigated. Grafting yield increased with increasing pre-irradiation dose, grafting temperature, and monomer concentration. Grafting rate depends on length of molecular chain in the monomers and decreases with increasing chain length. The grafting yields of electron beam irradiated samples were higher than those of γ-irradiated ones because of higher radical concentration. Tensile strength of the grafted film in the dried state increased and the elongation at break decreased with increasing degree of grafting. On the other hand, in the wet state, the tensile strength and elongation at break decreased with increasing the degree of grafting due to the lack of hydrogen bonds between the grafted chains caused by increased water absorption.     

Effect of Organic Binder Segregation on Sintered Strength of Dry-Pressed Alumina

The influence of binder systems on the structure and properties of alumina ceramics was examined. Two types of binders were used to prepare alumina granules by spray drying: poly-acrylic acid (PAA) and poly-vinyl alcohol (PVA). PVA segregated to the surface and subsurface of the granules, whereas PAA was homogeneously distributed. Compaction tests on a single granule showed that the PAA binder provides lower yield stress of granules than PVA. In the die compaction process, the relative density of the compact body started to increase at a lower pressure, and a more homogeneous internal structure was observed in the green compact prepared with the PAA binder than PVA. The homogeneous structure resulted in a sintered body with a strength of 580 vs 485 MPa when PVA was used.     

Molecular Species of Phospholipids with Very Long Chain Fatty Acids in Skin Fibroblasts of Zellweger Syndrome

The ratio of C_26:0/C_22:0 fatty acids in patient lipids is widely accepted as a critical clinical criterion of peroxisomal diseases, such as Zellweger syndrome and X-linked adrenoleukodystrophy (X-ALD). However, phospholipid molecular species with very long chain fatty acids (VLCFA) have not been precisely characterized. In the present study, the structures of such molecules in fibroblasts of Zellweger syndrome and X-ALD were examined using LC–ESI–MS/MS analysis. In fibroblasts from Zellweger patients, a large number of VLCFA-containing molecular species were detected in several phospholipid classes as well as neutral lipids, including triacylglycerol and cholesteryl esters. Among these lipids, phosphatidylcholine showed the most diversity in the structures of VLCFA-containing molecular species. Some VLCFA possessed longer carbon chains and/or larger number of double bonds than C_26:0-fatty acid (FA). Similar VLCFA were also found in other phospholipid classes, such as phosphatidylethanolamine and phosphatidylserine. In addition, VLCFA-containing phospholipid species showed some differences among fibroblasts from Zellweger patients. It appears that phospholipids with VLCFA, with or without double bonds, as well as C_26:0-FA might affect cellular functions, thus leading to the pathogenesis of peroxisomal diseases, such as Zellweger syndrome and X-ALD.