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  • 2005-2009
  • 2000-2004  (112)
  • 1925-1929
  • 2000  (112)
  • 1
    Electronic Resource
    Electronic Resource
    Plasma diagnostics and low-temperature deposition of microcrystalline silicon films in ultrahigh-frequency silane plasma (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 576-581 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Microcrystalline silicon thin films were formed on quartz substrates by ultrahigh-frequency (UHF) plasma enhanced chemical vapor deposition from a mixture of silane (SiH4) and hydrogen (H2) gases at low substrate temperatures (Ts). The UHF plasma was excited at a frequency of 500 MHz. The deposition rate and the crystallinity of the films were investigated as a function of H2 dilution, total pressure, mixture ratio of SiH4 to H2 and Ts. A crystalline fraction of 63% with a high deposition rate of 7.7 Å/s was obtained even at a Ts of 100 °C. At a temperature of 300 °C, a crystalline fraction of approximately 86% was achieved at a deposition rate of 1.4 Å/s. Diagnostics of the UHF plasma have been carried out using a Langmuir probe, ultraviolet absorption spectroscopy, and optical emission spectroscopy. Good crystallinity was explained by the balance of the sheath voltage and atomic hydrogen densities in the UHF plasma. Namely, the UHF plasma source achieving a high density plasma with a low electron temperature enabled us to reduce the ion bombardment energy incident on the substrates while maintaining a high density of hydrogen atoms, and which improved the crystallinity at low Ts. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373698
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  • 2
    Electronic Resource
    Electronic Resource
    Analysis of electric field distribution in GaAs metal–semiconductor field effect transistor with a field-modulating plate (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 3483-3487 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electric field distribution in the channel of a field effect transistor (FET) with a field-modulating plate (FP) has been theoretically investigated using a two-dimensional ensemble Monte Carlo simulation. This analysis revealed that the introduction of FP is effective in canceling the influence of surface traps under forward bias conditions and in reducing the electric field intensity at the drain side of the gate edge under pinch-off bias conditions. This study also found that a partial overlap of the high-field region under the gate and that at the FP electrode is important for reducing the electric field intensity. The optimized metal–semiconductor FET with FP (FPFET) (LGF∼0.2 μm) exhibited a much lower peak electric field intensity than a conventional metal–semiconductor FET. Based on these numerically calculated results, we have proposed a design procedure to optimize the power FPFET structure with extremely high breakdown voltages while maintaining reasonable gain performance. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372370
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  • 3
    Electronic Resource
    Electronic Resource
    Measurement and control of absolute nitrogen atom density in an electron-beam-excited plasma using vacuum ultraviolet absorption spectroscopy (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1756-1759 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The absolute nitrogen (N) atom density in an electron-beam-excited plasma (EBEP) operating at an ultralow pressure has been investigated by vacuum ultraviolet absorption spectroscopy, employing a microdischarge hollow-cathode lamp. The measured N atom density was estimated to be around 6×1011 cm−3, and the dissociation fraction was 4.9% at a N2 pressure of 0.05 Pa, an electron-beam current of 10 A, and an electron-beam acceleration voltage of 120 V. The EBEP potentially enables us to control the electron density and electron energy independently with the electron-beam current and electron-beam acceleration voltages, respectively. It was found that N atom densities increased with increasing electron-beam current and electron acceleration voltage under low-pressure conditions. The EBEP shows great promise as a N atom source operating at an ultralow pressure. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1305559
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  • 4
    Electronic Resource
    Electronic Resource
    Kinetics and role of C, O, and OH in low-pressure nanocrystalline diamond growth (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 4572-4579 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A simple low-pressure condition at 80 mTorr has been employed to study the kinetics and role of C, O, and OH in diamond growth by using inductively coupled CO/CH4/H2 and O2/CH4/H2 plasmas. Vacuum ultraviolet absorption spectroscopy (VUVAS) and actinometric optical emission spectroscopy (OES) were used to examine the densities of ground-state C atoms and emissive species such as OH, C2, and O, respectively. Diamond films consisting of nanocrystallites with sizes as small as 20 nm were obtained on positively biased Si substrates only when CH4 was fed. Both diamond and nondiamond growth were enhanced with increasing CO for a fixed CH4 concentration of 5%, while diamond growth was suppressed with increasing O2. Comprehensive discussion along with the VUVAS and OES results suggested that the C atoms resulting mainly from CO by electron impact dissociation had a close relation with the formation of C2 or still larger species as the precursors to nondiamond phase, while the OH radicals resulting predominantly by loss reactions of the byproduct O atoms with H2 and CH4 were highly responsible for the enhanced diamond growth. A large amount of O atoms from O2 was shown to affect the initial nucleation stage seriously. The results support the growth chemistry of diamond from H-hybridized carbon radicals fragmented from CH4 rather than from H-stripped carbon radicals. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373104
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  • 5
    Electronic Resource
    Electronic Resource
    Precursors of fluorocarbon film growth studied by mass spectrometry (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 7185-7190 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The precursor species of fluorocarbon film growth at the reactor wall irradiated by an electron cyclotron resonance C4F8 plasma have been studied by using a quadrupole mass spectrometer. The amount of polymeric neutral species [CmFn (m≥2)] and absolute densities of CFx (x=1–3) radicals in the vicinity of the wall were measured by electron attachment and threshold ionization mass spectrometry, respectively. The trends in the film growth rate as a function of gas residence time, diluted hydrogen concentration, and microwave power were well accounted for by the competition between the incorporation of CFx radicals and positive ions and the removal by F and H atoms. The fluxes of CFx radicals and positive ions incident upon the wall were shown to be comparable with the net condensed carbon flux derived from the growth rate. In contrast, the trends in the amount of polymeric neutrals were not well correlated to the growth rate. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.372967
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  • 6
    Electronic Resource
    Electronic Resource
    Blockade of RAGE–amphoterin signalling suppresses tumour growth and metastases (2000)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 405 (2000), S. 354-360 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The receptor for advanced glycation end products (RAGE), a multi-ligand member of the immunoglobulin superfamily of cell surface molecules, interacts with distinct molecules implicated in homeostasis, development and inflammation, and certain diseases such as diabetes and Alzheimer's ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35012626
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  • 7
    Electronic Resource
    Electronic Resource
    Enhancement in the perfection of orthorhombic lysozyme crystals grown in a high magnetic field (10 T) (2000)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 56 (2000), S. 1079-1083 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Orthorhombic crystals of hen egg-white (HEW) lysozyme were grown in a homogeneous and static magnetic field of 10 T. All crystals grown at 10 T were oriented such that their crystallographic c axes were parallel to the magnetic field direction and showed a narrower average full-width at half-maximum (FWHM) of the rocking curve than those grown at 0 T. Rocking-width measurements were made at the BL-10A station at the Photon Factory, Tsukuba, Japan, using a high-resolution vertical-type four-circle diffractometer. Crystal perfection was evaluated using the FWHM of the rocking curve; the effects of the magnetic field on the quality of the crystals were examined by comparison of the FWHM of seven crystals grown at 10 and 0 T. The FWHMs of the reflections along the a, b and c axes decreased by 23.5, 35.3 and 27.8%, respectively, and those of other general reflections decreased by 17.4–42.2% in the crystals grown at high magnetic field. These results clearly showed that a magnetic field of 10 T improved the crystal perfection of the orthorhombic lysozyme crystals. As a result, the maximum resolution of X-ray diffraction increased from 1.3 Å at 0 T to 1.13 Å at 10 T. The magnetic field also affected the dimensions of the unit cell, increments being 0.2% for the a and c axes and 0.1% for the b axis, respectively. These facts suggest that the application of a high magnetic field during crystallization might result in remarkable enhancements in the diffraction power of protein crystals having magnetic anisotropy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444900008155
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  • 8
    Electronic Resource
    Electronic Resource
    Shoot structure and dynamics of saplings and canopies of three deciduous broad-leaved trees of a coppice forest in central Japan (2000)
    Springer
    Trees 14 (2000), S. 206-214 
    Details
    ISSN: 0931-1890
    Keywords: Key words  Castanea crenata ; Carpinus laxiflora ; Quercus serrata. ; Shoot phenology ; Shoot elongation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Three deciduous broad-leaved trees, Quercus serrata, Castanea crenata and Carpinus laxiflora, were the main constituents of a coppice forest in central Japan. The shoot elongation and leaf emergence modes of both saplings and the canopy of the three species were investigated. The shoot elongation modes of Q. serrata and C. crenata were the same in saplings and the upper layer of the canopy. The second shoots of these two species were formed after the first shoots were elongated. C. laxiflora was different between saplings and the upper layer of the canopy. In saplings, only the first shoots took a long time to elongate. In the upper canopy layer, higher order shoots were formed in the same way as in the other two species. In the lower layer of the canopy, all three species showed the same shoot elongation mode, in which only the first shoot and its duration of elongation was short. Leaf longevity, individual leaf area, leaf mass per unit leaf area and the stem mass per unit stem length of C. laxiflora were significantly shorter or significantly smaller than those of Q. serrata and C. crenata. The length of the stem per unit leaf area of C. laxiflora was three times that of Q. serrata and five times that of C. crenata. The elongation growth of C. laxiflora was highly efficient as it occurred with a small leaf area. The shoot dynamics and the shoot structure of C. laxiflora are more suitable for elongation growth than in Q. serrata and C. crenata. Furthermore, the shoot structures of the three species were compared and ecological characteristics of the three species are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009764
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  • 9
    Electronic Resource
    Electronic Resource
    Identification of 187 single nucleotide polymorphisms (SNPs) among 41 candidate genes for ischemic heart disease in the Japanese population (2000)
    Springer
    Human genetics 〈Berlin〉 106 (2000), S. 288-292 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. To investigate whether common variants in the human genetic background are associated with pathogenesis of ischemic heart diseases, we systematically surveyed 41 possible candidate genes for single-nucleotide polymorphisms (SNPs) by directly sequencing 96 independent alleles at each locus, derived from 48 unrelated Japanese patients with myocardial infarction, including 25.8 kb 5' flanking regions, 56.8 kb exonic and 35.4 kb intronic sequences, and 1.8 kb 3' flanking regions. In this genomic DNA of nearly 120 kb, we identified 187 SNPs: 55 in 5' flanking regions, seven in 5' untranslated regions (UTRs), 52 in coding elements, 64 in introns, eight in 3' UTRs, and one in a 3' flanking region. Among the 52 coding SNPs, 26 were non-synonymous changes. Allelic frequencies of some of the polymorphisms were significantly different from those reported in European populations. For example, the Q506R substitution in the coagulation factor V gene, the so-called "Leiden mutation", has a reported frequency of 2.3% in Europeans, but we detected the Leiden mutation in none of the Japanese genomes that we investigated. The allelic frequencies of the –33A〉G SNP in the thrombomodulin gene were also very different; this allele occurred at a 12% frequency in the Japanese patients that we examined, although it had been detected in none of 82 Caucasians reported previously. These data support the hypothesis that some SNPs are specific to particular ethnic groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004390000247
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  • 10
    Electronic Resource
    Electronic Resource
    Resident macrophages activated by lipopolysaccharide suppress muscle tension and initiate inflammatory response in the gastrointestinal muscle layer (2000)
    Springer
    Histochemistry and cell biology 113 (2000), S. 73-80 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  A great number of macrophages is found to be evenly distributed in the muscle layer of the gastrointestinal tract. We investigated their effects on smooth muscle contraction and the initiation of immune reactions such as inflammatory responses. Macrophages were demonstrated by the uptake of FITC-dextran and their ultrastructural features were elucidated by electron microscopy. Muscle layers of rats’ ileums were incubated with lipopolysaccharide (LPS) for 4–8 h and the force of smooth muscle contraction was measured. The induction effect of inducible nitric oxide synthase (iNOS) on macrophages was then checked by immunohistochemistry. The expression of major histocompatibility complex (MHC) class II was also examined. Macrophages in the muscle layer were confirmed as resident macrophages and were different from a population of dendritic cells. After incubation with LPS, macrophages began to express iNOS and produced NO, and it reduced smooth muscle contraction. iNOS-immunopositive cells increased in a time-dependent manner. Macrophages also began to express MHC class II. The total number of macrophages did not alter after incubation. Results indicate that resident macrophages in the muscle layer induced iNOS as an inflammatory reaction, affected smooth muscle contraction, and initiated immune response in the smooth muscle layer of the gastrointestinal tract, when activated by LPS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004180050009
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