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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 2896-2903 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Amorphous SiNx:H films having nitrogen content x greater than 1.3 were deposited at 300 °C by varying the ammonia-to-monosilane flow-rate ratio RN, using plasma-enhanced chemical- vapor-deposition. The characteristics of defects in the films subjected to UV illumination and anneal treatments were investigated by electron-spin-resonance (ESR) measurements. The paramagnetic Si dangling bonds (DBs) with three N atom neighbors, called the K0 center, were observed for an as-deposited film with RN of 5, and the density was favorably enhanced by exposing the film to UV light or by the UV illumination subsequent to its annealing. The K0 density decreased as the film was annealed at 550 °C after the UV illumination. The mechanisms of creation and disappearance of the K0 centers by the illumination and the annealing, respectively, were interpreted in terms of the potential fluctuation model. The K0 density in as-deposited films decreased with RN, and a new three-line spectrum was observed as RN exceeds 7. Origins of this new spectrum are discussed. The ESR spectra due to N DBs were observed for only the films subjected to the anneal/illumination sequence, and the densities of both N DBs and K0 centers decreased with increasing the annealing time before the illumination. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 4055-4061 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Diamond films were successfully synthesized in both parallel-plate radio frequency (rf: 13.56 MHz) CH4 and CH3OH plasmas with injection of H and OH radicals generated in the remote microwave (2.45 GHz) H2/H2O plasma. Effects of H, OH, and CH3 radicals on the diamond film formation in the rf plasma reactor were investigated by the formation of diamond films employing radical injection technique and the measurement of density in the plasma. Under the condition of diamond film formation, CH3 density was measured by infrared diode laser absorption spectroscopy (IRLAS). The kinetics of CH3 in rf CH4 and CH3OH plasmas with injection of H and OH radicals were evaluated from the results of optical emission spectroscopy and lifetime of CH3 radicals estimated by IRLAS. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 3893-3895 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the gain characteristics of gain-guided quantum well II–VI laser diodes by measuring the amplified spontaneous emission spectra under several pulsed conditions. The temperature rise during one current pulse affects the gain characteristics and the L-I characteristics. The net modal gain at constant peak current increases with the pulse width. The peak gain for long pulses shows a superlinear dependence on injection current. In this case, the L-I curve is very steep above threshold and sometimes shows an internal quantum efficiency of more than unity. This leads to an underestimation of the internal cavity loss giving a value inconsistent with the one obtained from the gain spectra. With short pulse currents (〈200 ns), the peak gain shows a weak sublinear dependence on injection current. The cavity losses obtained from the gain spectra and the L-I characteristics at short pulses are consistent. As a result, we obtain the intrinsic gain characteristics of gain-guided quantum well II–VI laser diodes. © 1996 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 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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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 3483-3485 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence (PL) characteristics of Se-doped Ga0.5In0.5P/(Al0.5Ga0.5)0.5In0.5P double heterostructure (DH) on GaAs substrates were investigated at room temperature. The PL intensity and the decay time both strongly depend on the cladding-layer carrier density. Up to a carrier density of 2.5×1017 cm−3, the PL intensity increases linearly with carrier density, while the decay time is almost constant. For carrier densities larger than 2.5×1017 cm−3, the PL intensity and the decay time decrease linearly and quadratically with carrier density, respectively. We also studied the PL characteristics of Se-doped Ga0.5In0.5P and (Al0.5Ga0.5)0.5In0.5P single layers on GaAs substrates. We found that the carrier density dependence of DH governed by the cladding layer is similar to that of (Al0.5Ga0.5)0.5In0.5P single layers. These results indicate that a nonradiative interfacial recombination process dictates the DH PL characteristics and that the quality of the cladding layer affects the PL radiative efficiency. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental pharmacology and physiology 22 (1995), S. 0 
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. The present study examined the effect of heparin on nitric oxide (NO) formation and cyclic guanosine 3′, 5′-monophos-phate (cGMP) levels in cultured aortic endothelial cells (EC) from spontaneously hypertensive rats (SHR) and normoten-sive Wistar-Kyoto (WKY) rats.2. Bradykinin (BK), adenosine diphosphate (ADP), Ca2+ ionophore A23187 (Io) and endothelin-3 (ET-3) stimulated the production of NO and cGMP. No significant difference was observed in both NO and cGMP production in EC between WKY and SHR.3. Heparin enhanced BK-, ADP-, Io- and ET-3–stimulated NO and cGMP production. These enhancements by heparin in EC were significantly greater in SHR than in WKY.4. Both NO formation and cGMP production stimulated by the agonists and/or heparin were blocked in the presence of NG-monomethyl-L-arginine (LNMMA, 10-5mol/L).5. Increased sulphur level was observed on heparin-treated SHR EC surface compared with that on control SHR EC or on heparin-treated WKY EC surface.6. These results suggest that heparin promotes agonist-induced NO-cGMP response in cultured EC from SHR.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1440-1681
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: 1. Endothelin (ET) B-type (ETB) receptor-mediated signal transduction was examined after stimulation with ET-3 in cultured aortic endothelial cells (EC) from spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats (8 weeks old).2. The EC from both rat strains expressed only ETB receptor mRNA. The receptor densities and affinities, which were non-selective for ET-1, -2, -3 and Sarafotoxin S6c, and mRNA expression were similar in WKY and SHR.3. The cytosolic Ca2+ level in the absence of extracellular Ca2+, inositol 1,4,5-trisphosphate levels, protein kinase C and phospholipase C activities in response to ET-3 were greater in SHR EC than in WKY EC.4. The 45Ca uptake in response to ET-3, which was blocked by Ni2+, was smaller in SHR EC than in WKY EC.5. The 6-keto-PGF1α production was augmented in SHR, though nitric oxide formation after stimulation with ET-3 was similar.6. These results suggest that ETB receptor-mediated phosphoinositide turnover signalling is augmented in SHR EC through postreceptor mechanism.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2307
    Keywords: Key words Apoptosis ; Gastric carcinoma ; Minute carcinoma ; Progression ; Oncogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We examined the relationship between apoptosis and the progression of human gastric carcinoma. Studies were conducted on a total of 88 surgically removed stomachs, comprising 26 minute (less than 5 mm in diameter), 29 early (limited to the mucosal and submucosal layer) and 33 advanced carcinomas. Apoptotic cells were visualized by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labelling (TUNEL). Serial sections were immunostained for p53 and Ki-67. The mean apoptotic indices (AI: percentage of TUNEL signal positive cells) of minute, early, and advanced carcinomas were 4.1±0.6, 3.8±1.2, and 4.0±1.2 in 46 well differentiated carcinomas, and 2.1±0.5, 2.7±0.9, and 2.2±1.1 in 42 poorly differentiated carcinomas, respectively. Similarly, the mean Ki-67 labelling indices (KI) were 39.2±7.8, 47.2±12.8, 52.6±13.1 in the former, and 35.0±9.3, 36.9±10.3, and 40.0±9.2 in the latter, respectively. Both mean AI and mean KI were significantly higher in well differentiated than in poorly differentiated carcinomas (P〈0.05). However, the value of mean AI did not differ among minute, early, and advanced carcinomas in either histological type, while KI increased gradually with tumour progression. The frequency of nuclear p53 expression did not differ among the three categories, implying that the gene mutation is an early event in gastric carcinogenesis. There was no statistical significance between nuclear p53 expression and mean AI. These results suggest that the progression of gastric cancer is defined by a gradual increase of proliferative activity and constant occurrence of apoptosis and that naturally occurring apoptosis is induced predominantly via a p53-gene-independent pathway.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 30 (1996), S. 121-126 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Venous blood samples, 24-h total food duplicate samples, and rice samples were collected from 52 adult nonsmoking women in the city of Tainan, southern Taiwan, in 1994, and analyzed for cadmium (Cd) and lead (Pb) by wet-digestion followed by graphite furnace atomic absorption spectrophotometry. Daily dietary intake was 10 |gmg for Cd and 22 μg for Pb as geometric means, of which Cd and Pb in rice accounted for 34% and 1.4% of daily Cd and Pb intakes, respectively. The counterpart values for blood were 1.11 ng/ml and 44.5 ng/ml for Cd and Pb, respectively. International comparison with recently published data suggests that the exposure to Cd in Tainan should be among the lowest in the world.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 30 (1996), S. 121-126 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Venous blood samples, 24-h total food duplicate samples, and rice samples were collected from 52 adult nonsmoking women in the city of Tainan, southern Taiwan, in 1994, and analyzed for cadmium (Cd) and lead (Pb) by wetdigestion followed by graphite furnace atomic absorption spectrophotometry. Daily dietary intake was 10 μg for Cd and 22 μg for Pb as geometric means, of which Cd and Pb in rice accounted for 34% and 1.4% of daily Cd and Pb intakes, respectively. The counterpart values for blood were 1.11 ng/ml and 44.5 ng/ml for Cd and Pb, respectively. International comparison with recently published data suggests that the exposure to Cd in Tainan should be among the lowest in the world.
    Type of Medium: Electronic Resource
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