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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 1714-1719 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A beam chopping system for a cyclotron is in operation at the JAERI cyclotron facility. A combination of a pulse voltage chopper in the injection line and a sinusoidal voltage chopper after the exit of the cyclotron is adopted to produce beam pulses spaced at 1 μs–1 ms intervals from natural cyclotron beams. The chopping system was designed according to a simple formulation of the chopping process in which the multiturn extraction was taken into account. Performance of the chopping system was experimentally proved to satisfy requirements of the design. In actual operation to produce beam pulses at long intervals, however, the number of the multiturn extraction is usually larger than the assumed value in the design because of a large phase acceptance of the cyclotron. Careful tuning of the acceleration phase width or the base magnetic field of the cyclotron is necessary to reduce it. It is essential to strictly define the acceleration phase of injected beams in the central region of the cyclotron to improve this situation. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 3881-3883 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The first subband energy at the valence band of self-assembled silicon quantum dots grown by low-pressure chemical vapor deposition on ultrathin SiO2/Si substrates has been measured as an energy shift at the top of the valence band density of states by using high-resolution x-ray photoelectron spectroscopy. The systematic shift of the valence band maximum towards higher binding energy with decreasing the dot size is shown to be consistent with theoretical prediction. The charging effects of the silicon dots and the SiO2 layer by photoelectron emission during the measurements have been taken into account in determining the valence-band-edge energy. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Chemical shifts of Si–Hx (x=1,2) species on Si surfaces obtained by ex situ chemical treatment have been evaluated by high-resolution x-ray photoelectron spectroscopy at a take-off angle of 5°. Optimizing the water rinse and sample loading conditions enables identification of the Si–Hx components of the Si 2p core-level spectra, whose intensities display strong dependence on crystallographic orientation and surface treatment. NH4F-treated Si(111) exhibits almost exclusive monohydride termination which induces a chemical shift of 250 meV relative to the bulk component. On the other hand, 4.5% HF-treated Si(111) and 1% HF-treated Si(100) surfaces show increased dihydride termination with an associated shift of 480 meV. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 2291-2293 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Nanometer-scale Si quantum dots have been spontaneously fabricated on SiO2 by controlling the early stages of low-pressure chemical vapor deposition from pure silane. The tunneling current through Au/1 nm-SiO2/a single Si quantum dot/1 nm-SiO2/n+-Si(100) double-barrier structures has exhibited the clear current bump or negative conductance at 300 K with a peak current to valley ratio as high as 10. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 23 (1999), S. 364-373 
    ISSN: 1476-5535
    Keywords: Keywords: Sphingomonas paucimobilis; lignin degradation; β-aryl ether cleavage; biphenyl degradation; O-demethylation; protocatechuate 4,5-cleavage pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sphingomonas paucimobilis SYK-6 is able to grow on a wide variety of dimeric lignin compounds. These compounds are degraded via vanillate and syringate by a unique enzymatic system, composed of etherases, O demethylases, ring cleavage oxygenases and side chain cleaving enzymes. These unique and specific lignin modification enzymes are thought to be powerful tools for utilization of the most abundant aromatic biomass, lignin. Here, we focus on the genes and enzymes involved in β-aryl ether cleavage and biphenyl degradation. Two unique etherases are involved in the reductive cleavage of β-aryl ether. These two etherases have amino acid sequence similarity with the glutathione S-transferases, and use glutathione as a hydrogen donor. It was found that 5,5′-dehydrodivanillate, which is a typical lignin-related biphenyl structure, was transformed into 5-carboxyvanillate by the reaction sequence of O-demethylation, meta-ring cleavage, and hydrolysis, and the genes involved in the latter two reactions have been characterized. Vanillate and syringate are the most common intermediate metabolites in lignin catabolism. These compounds are initially O-demethylated and the resulting diol compounds, protocatechuate (PCA) and 3-O-methylgallate, respectively, are subjected to ring cleavage catalyzed by PCA 4,5-dioxygenase. The ring cleavage products generated are further degraded through the PCA 4,5-cleavage pathway. We have isolated and characterized genes for enzymes involved in this pathway. Disruption of a gene for 2-pyrone-4,6-dicarboxylate hydrolase (ligI) in this pathway suggested that an alternative route for 3-O-methylgallate degradation, in which ligI is not involved, would play a role in syringate catabolism. In this article, we describe the genetic and biochemical features of the S. paucimobilis SYK-6 genes involved in degradation of lignin-related compounds. A possible application of the SYK-6 lignin degradation system to produce a valuable chemical material is also described.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-069X
    Keywords: Key words Lysyl oxidase ; Gene expression ; Wound healing ; Type III collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lysyl oxidase (LOX) initiates the crosslinking of the lysine-derived aldehyde and plays an essential role in maturation of collagen, for example in wound healing. Although the activity of this enzyme has been examined in various disorders, and a further intriguing aspect of the relationship between LOX and tumorigenesis has recently emerged, its gene expression pattern in tissues is still unknown. We examined LOX gene expression during wound healing in rat skin. In addition, type III collagen gene expression was studied to determine the formation of fibrils. The LOX mRNA level reached a peak by day 3 after injury, which was earlier than that of type III collagen, and continued at a high level until day 22. The type III collagen mRNA level began to rise from day 3 and had increased intensely by day 22. In situ hybridization revealed grains corresponding to LOX mRNA in the fibroblasts of the granulomatous tissue. These results suggest that LOX is produced before collagen synthesis in preparation for crosslinking in the early phase of wound healing.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0428
    Keywords: NSY mouse ; non-insulin-dependent diabetes mellitus ; animal model ; insulin secretion ; isolated islets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The NSY (Nagoya-Shibata-Yasuda) mouse was established as an inbred strain of mouse with spontaneous development of diabetes mellitus, by selective breeding for glucose intolerance from outbred Jcl∶ICR mice. NSY mice spontaneously develop diabetes mellitus in an age-dependent manner. The cumulative incidence of diabetes is 98% in males and 31% in females at 48 weeks of age. Neither severe obesity nor extreme hyperinsulinaemia is observed at any age in these mice. Glucose-stimulated insulin secretion was markedly impaired in NSY mice after 24 weeks of age. In contrast, fasting plasma insulin level was higher in male NSY mice than that in male C3H/He mice (545±73 vs 350±40 pmol/l, p〈0.05, at 36 weeks of age). Pancreatic insulin content was higher in male NSY mice than that in male C3H/He mice (76±8 vs 52±5 ng/mg wet weight, p〈0.05, at 36 weeks of age). Morphologically, no abnormal findings, such as hypertrophy or inflammatory changes in the pancreatic islets, were observed in NSY mice at any age. These data suggest that functional changes of insulin secretion in response to glucose from pancreatic beta cells may contribute to the development of non-insulin-dependent diabetes mellitus (NIDDM) in the NSY mouse. Although insulin sensitivity was not measured, fasting hyperinsulinaemia in NSY mice suggests that insulin resistance may also contribute to the pathogenesis of NIDDM. Since these findings are similar to the pathophysiologic features of human NIDDM patients, the NSY mouse is considered to be useful for investigating the pathogenesis and genetic predisposition to NIDDM.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0428
    Keywords: Key words NSY mouse ; non-insulin-dependent diabetes mellitus ; animal model ; insulin secretion ; isolated islets.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The NSY (Nagoya-Shibata-Yasuda) mouse was established as an inbred strain of mouse with spontaneous development of diabetes mellitus, by selective breeding for glucose intolerance from outbred Jcl:ICR mice. NSY mice spontaneously develop diabetes mellitus in an age-dependent manner. The cumulative incidence of diabetes is 98 % in males and 31 % in females at 48 weeks of age. Neither severe obesity nor extreme hyperinsulinaemia is observed at any age in these mice. Glucose-stimulated insulin secretion was markedly impaired in NSY mice after 24 weeks of age. In contrast, fasting plasma insulin level was higher in male NSY mice than that in male C3H/He mice (545 ± 73 vs 350 ± 40 pmol/l, p 〈 0.05, at 36 weeks of age). Pancreatic insulin content was higher in male NSY mice than that in male C3H/He mice (76 ± 8 vs 52 ± 5 ng/mg wet weight, p 〈 0.05, at 36 weeks of age). Morphologically, no abnormal findings, such as hypertrophy or inflammatory changes in the pancreatic islets, were observed in NSY mice at any age. These data suggest that functional changes of insulin secretion in response to glucose from pancreatic beta cells may contribute to the development of non-insulin-dependent diabetes mellitus (NIDDM) in the NSY mouse. Although insulin sensitivity was not measured, fasting hyperinsulinaemia in NSY mice suggests that insulin resistance may also contribute to the pathogenesis of NIDDM. Since these findings are similar to the pathophysiologic features of human NIDDM patients, the NSY mouse is considered to be useful for investigating the pathogenesis and genetic predisposition to NIDDM. [Diabetologia (1995) 38: 503–508]
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0428
    Keywords: Β3-adrenergic-receptor gene ; susceptibility ; missense mutation ; non-insulin-dependent diabetes mellitus ; insulin resistance syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A possible pathogenic mutation in the Β3-adrenergic-receptor gene (Trp64Arg) has been reported to be associated with an earlier age of onset of non-insulin-dependent diabetes mellitus (NIDDM) and clinical features of the insulin resistance syndrome in Pima Indian, Finnish and French subjects. Since marked heterogeneity has been reported in the association of mutations of candidate genes with NIDDM between Japanese and other ethnic groups, we investigated the association of Trp64Arg with NIDDM in Japanese subjects. The allele frequency of the mutation (Arg) was slightly, but not significantly, higher in NIDDM than in control subjects (70 out of 342 alleles [20.5%] vs 40 out of 248 [16.1%], respectively, p〉0.2). When our data were combined with those of Pima Indian and Finnish subjects, however, the Arg/Arg genotype was significantly associated with NIDDM as compared with the other two genotypes (p〈0.005, relative risk [RR] 2.13, 95% confidence interval [CI] 1.28–3.55). The Arg allele was also associated with NIDDM (p〈0.05, RR 1.27, 95% CI 1.06–1.52). Japanese subjects homozygous for the mutation had a significantly higher body mass index (mean ± SD∶25.5±3.9 kg/ m2) than heterozygotes (22.6±4.1, p〈0.05) and normal homozygotes (22.8±3.8, p〈0.05). NIDDM patients homozygous for the mutation tended to have an earlier age of onset of NIDDM than those with other genotypes. These data suggest that the Trp64Arg mutation not only contributes to weight gain and age-at-onset of NIDDM but is also associated with susceptibility to NIDDM.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0428
    Keywords: Glucagon receptor gene ; susceptibility ; missense mutation ; non-insulin-dependent diabetes mellitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A possible pathogenic mutation in the glucagon receptor gene causing a Gly to Ser change at codon 40 (Gly40Ser) was reported to be associated and linked with non-insulin-dependent diabetes mellitus (NIDDM), in France and Sardinia, Since the frequency of the mutation (Gly40Ser), about 5% in the French population of familial NIDDM and 8% in randomly chosen diabetic patients in Sardinia, was much higher than that of any of the previously reported mutations in candidate genes, it is important to clarify whether the contribution of this mutation to NIDDM is universal. In this study, we investigated the association of this mutation with diabetes mellitus in a large number of Japanese diabetic patients (383 NIDDM and 53 insulin-dependent diabetic patients) by polymerase chain reaction-restriction fragment length polymorphism analysis. None of the Japanese diabetic patients showed Gly40Ser mutation and the association of this mutation with NIDDM was significantly different (p〈4·10−5 vs French, p〈3·10−6 vs Sardinian by Fisher's exact test). The results not only indicate that the mutation plays little, if any, role in susceptibility to diabetes in Japan, but also indicate the genetic heterogeneity in NIDDM and further emphasize the importance of studies on genetic susceptibility to NIDDM and other complex traits in different ethnic groups.
    Type of Medium: Electronic Resource
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