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  • 1
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 2049-2051 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: 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.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 1714-1719 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: 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.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 3881-3883 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: 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.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 2291-2293 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: 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.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1432-5233
    Schlagwort(e): Key words Non-insulin-dependent diabetes mellitus ; MODY ; Hepatocyte nuclear factor-1α ; Genetics ; Microsatellite polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Recently, hepatocyte nuclear factor-1α (HNF-1α, which is encoded by the TCF1 gene) mutations were reported in a subset of patients with maturity onset diabetes of the young (MODY3). We studied the contribution of TCF1 to genetic susceptibility to common non-insulin-dependent diabetes mellitus (type 2) in Japanese subjects by investigating allelic association with type 2 diabetes use of three markers. We also studied the frequency of the G191D mutation, the only mutation of TCF1 reported so far in late-onset type 2 diabetes. A total of 356 subjects were studied. There were no significant differences in allele frequency of the three markers between patients with type 2 diabetes and control subjects. A G191D mutation was not found in the subjects studied, giving a frequency of less than 0.4% in common type 2 diabetes. The lack of association of type 2 diabetes with three markers in and near TCF1 suggests that mutations in TCF1 derived from a limited number of founders are not a major cause of common type 2 diabetes even in the genetically homogeneous Japanese population. The data also indicate that the G191D mutation in TCF1 plays little, if any, role in susceptibility to common type 2 diabetes in the Japanese.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-069X
    Schlagwort(e): Key words Lysyl oxidase ; Gene expression ; Wound healing ; Type III collagen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0428
    Schlagwort(e): Β3-adrenergic-receptor gene ; susceptibility ; missense mutation ; non-insulin-dependent diabetes mellitus ; insulin resistance syndrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-0428
    Schlagwort(e): Key words Glucagon receptor gene ; susceptibility ; missense mutation ; non-insulin-dependent diabetes mellitus.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: 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. [Diabetologia (1995) 38: 983–985]
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-0428
    Schlagwort(e): Keywords Angiotensin I-converting enzyme gene ; I/D polymorphism ; meta-analysis ; diabetic nephropathy ; diabetic retinopathy ; genetic susceptibility.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene has repeatedly been shown to be associated with ischaemic heart disease, but the association of this genetic marker with diabetic microangiopathy is controversial. To assess the association of the genotypes with the development of diabetic nephropathy or retinopathy, we performed a meta-analysis of data from the literature, using Mantel-Haenszel method followed by the Breslow-Day test for assessing homogeneity among data. In a total of 4773 diabetic patients from 18 studies with (n = 2495) and without (n = 2278) renal complications, the D allele was significantly associated with diabetic nephropathy (p 〈 0.0001) in a dominant model (summary odds ratio 1.32, 95 % confidence interval: 1.15 to 1.51). There was no significant evidence against homogeneity of the odds ratios (χ 2 = 18.9, 20 df; p = 0.53). The association was significant both in non-insulin-dependent (p 〈 0.005) and in insulin-dependent diabetes mellitus (p 〈 0.05). Likewise, in a total of 2010 diabetic patients with (n = 1008) and without (n = 1002) retinopathy, there was no association of the I/D polymorphism with diabetic retinopathy. These data suggest that the ACE I/D polymorphism affects the risk for diabetic nephropathy, but not for diabetic retinopathy. [Diabetologia (1998) 41: 47–53]
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Acta neurochirurgica 138 (1996), S. 695-699 
    ISSN: 0942-0940
    Schlagwort(e): Acoustic neurinoma ; computerized tomography ; cystic tumour ; magnetic resonance imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cystic acoustic neurinomas (ANs) are less frequent and are different from solid ANs in clinical and radiological features. We had 14 cystic ANs (13.5% of 104 cases) in the last 17 years. Computerized tomographic or magnetic resonance images allowed for the classification of these cystic ANs into three types: Type A being large single cysts with a thin tumourous wall (7 cases); type B single cysts with a thick tumourous wall (3 cases); type C multicystic (4 cases). Half of the cystic ANs were not accompanied by enlargement of the internal auditory canal, despite the largeness of the cysts. The mean size of the tumours was 29 mm in diameter. Type A cysts had a shorter clinical history than types B and C. One patient had intact hearing. In five cases, an atypical initial symptom such as facial pain, dysgeusia, facial palsy, unsteadiness or vertigo presented. The trigeminal nerve was involved in 12 cases, the facial nerve in nine. The characteristic features of cystic ANs are largeness of the tumour, a short clinical history, an atypical initial symptom, facial nerve involvement, and/or no enlargement of the internal auditory canal. In addition, the histological features are a lobular growth pattern, high nuclear atypia, and numerous macro phages.
    Materialart: Digitale Medien
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