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  • 2000-2004  (9)
  • 1980-1984
  • 2000  (9)
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 4553-4557 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Theoretical analysis and numerical modeling indicate that, under high fields, the director of a thin region of liquid crystal close to the wall of a twisted nematic cell returns to the "easy" axis on the interface. Polarization conversion reflectivity signals are recorded for half-leaky guided modes from a twisted nematic cell subject to high ac fields. By fitting model theory to reflectivities recorded for a particular region of incidence angles, the director twist at the cell walls is deduced. In the high-field limit, this then gives the original director alignment axis, the easy axis, at the wall of a twisted nematic cell. © 2000 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 88 (2000), S. 6515-6518 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Mg acceptors of GaN films are activated as p-type GaN with rapid thermal annealing (RTA) and furnace treatments. The GaN:Mg films are activated successfully by using the RTA system below 1000 °C for 1 min. After the RTA treatment, we observed a sharper linewidth and stronger emission intensities from donor to acceptor peaks in the photoluminescence spectra. By comparing the electrical properties of GaN:Mg films at optimum conditions made with RTA (800 °C) and furnace (700 °C) treatments, we find similar activated hole concentration and a higher hole mobility for GaN:Mg films with RTA treatment at 800 °C. A higher bulk resistivity caused by increasing nitrogen vacancies is found at higher temperature and longer time RTA treatments. Faster treatment times and lower temperatures for the GaN:Mg films were achieved with the RTA activation process. © 2000 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 77 (2000), S. 3161-3163 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: 20 mm long ropes consisting of soundly aligned single-walled carbon nanotube (SWNT) ropes, synthesized by the catalytic decomposition of hydrocarbons, were employed for direct tensile strength measurements. The average tensile strength of SWNT rope composites is as high as 3.6±0.4 GPa, similar to that of carbon fibers. The tensile strength of SWNT bundles was extrapolated from the strength of the composites to be 2.3±0.2 to 14.2±1.4 GPa after simply taking into account the volume fraction of SWNT bundles in the minicomposite, and the tensile strength of single SWNTs was estimated to be as high as 22.2±2.2 GPa. The excellent mechanical properties of SWNTs will make them an ideal reinforcement agent for high performance composite materials. © 2000 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 76 (2000), S. 1878-1880 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this letter, we investigate a metalization process for reducing the contact resistance on undoped GaN layers. The Si metal source was diffused successfully into the GaN films by using SiOx/Si/GaN/Al2O3 structures. By using a high-temperature annealing process, we diffused and activated the Si atoms into the GaN film. This caused a heavy doped n-type GaN layer to be formed near the GaN surface. Under high temperatures, such as a diffusion process at 1000 °C, the as-deposited Ni/Al/Ti contact had good ohmic properties and a low specific contact resistivity (ρc) of 1.6×10−3 Ω cm2. Rapid thermal annealing the contact at 800 °C for 30 s caused the ρc to decrease rapidly to 5.6×10−7 Ω cm2. The Ni/Al/Ti contact characteristics on the GaN films diffused at various temperatures are also discussed. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 12 (2000), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have previously demonstrated that hippocampal integrin-associated protein (IAP) gene expression is associated with memory formation in a one-way inhibitory avoidance learning in rats. In the present study, we further investigated the role and mechanism of IAP involved in memory consolidation in rats. Because of the minute amount of IAP present in the brain, we have adopted the quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. Our results revealed that hippocampal IAP mRNA expression is approximately fourfold higher in rats showing good memory retention (GM, retention score of 600 s) at 3 h, but not at other time points, after training when compared with the poor memory rats (retention score 〈 80 s). On the other hand, integrin αv mRNA level was markedly increased (∼ twofold), while integrin β3 mRNA level was decreased (∼ 50%) at 1 h post-training. Further, separate sets of RT-PCR analysis revealed that IAP5 and IAP6 mRNA expressions, but not that of IAP7, were markedly increased in GM rats 3 h post-training. Moreover, regional distribution studies revealed that different isoforms of the IAP gene are similarly distributed in different brain areas, while IAP7 has been the predominant form present in astrocyte cells. These results together suggest that IAP mRNA expression is indeed induced upon training, rather than that the GM rats have constitutively higher levels of IAP. The unparallel change of IAP and integrin mRNA expressions as far as time-course is concerned suggests that they are possibly involved in different forms and stages of memory processing. Further, IAP5 and IAP6 are more closely associated with memory consolidation, while IAP7 may constitute the major isotype for signal transduction in astrocyte cells.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Social psychiatry and psychiatric epidemiology 35 (2000), S. 463-470 
    ISSN: 1433-9285
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract   Background: This study set out to determine to what extent recalled parental rearing styles (authoritarian, authoritativeness, permissiveness), personality (extraversion, neuroticism, psychoticism, lie), and self-esteem predicted self-rated happiness in a normal, non-clinical, population of young people in their late teens and early 20s. Methods: Each participant completed a few questionnaires: the Eysenck Personality Questionnaire (revised), the Rosenberg Self-Esteem Scale, the Parental Authority Questionnaire and the Oxford Happiness Inventory. It was predicted that sex, extraversion, neuroticism, self-esteem and both maternal and paternal authoritativeness would be significant predictors of happiness. Results: Regressional and path analysis showed self-esteem to be the most dominant and powerful predictor of happiness. The effect of sex on happiness was moderated by neuroticism, which related to self-esteem, which directly influenced happiness. Stability, extraversion and maternal authoritativeness were significant predictors of self-esteem accounting for one-third of the variance. Conclusion: The results are considered in terms of the distinct literature on the relation between personality and happiness and on the relation between parental styles and self-esteem. Self-esteem was both a direct and a moderator variable for young people's self-reported happiness. Extraversion had both direct and indirect predictive power of happiness, whereas neuroticism predicted happiness mediating through self-esteem. Maternal authoritativeness was the only direct predictor of happiness when paternal and maternal rearing styles were examined together, suggesting that a reasonable discipline exercised by mothers towards their children was particularly beneficial in enhancing the off-springs' self-esteem.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0878
    Keywords: Raft cultures Keratinocytes Gap junctions Transcription Papillomavirus Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A decrease in gap junction-mediated cell-to-cell communication has previously been observed in monolayer cultures of human keratinocytes (HaCaT cells) expressing the human papillomavirus type 16 E5 (HPV16 E5) gene and attributed to the reduced phosphorylation of connexin 43, the most abundant connexin in HaCaT cells. In line with this observation, we have now analyzed the effect of HPV16 E5 on connexin 43 expression in raft cultures produced by transfected HaCaT cells. These keratinocytes transcribe HPV16 E5 under the control of a dexamethasone-inducible promoter. Our results show that treatment with dexamethasone leads to an almost complete disappearance of connexin 43 in rafts expressing the E5 gene but not in control rafts. In our study we discuss the possible effects of this downregulation on cell-cell communication and cellular malignant transformation.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Aquaculture international 7 (2000), S. 393-397 
    ISSN: 1573-143X
    Keywords: gene mapping ; PRINS ; Rice field eel Monopterus albus ; Sox
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The mammalian Y-linked sex determining gene, SRY (Sex determining region Y), encodes a protein with a DNA-binding domain, HMG box. In a wide variety of animal species, a large family of genes containing this highly homologous HMG box, which has been named Sox (SRY-related HMG box), have been identified. Several Sox genes have already been shown to be transcription factors involved in development. In the present study, using primed in situ labelling (PRINS), we report the chromosome mapping of two Sox genes in rice field eel Monopterus albus. The Sox9 gene was mapped to chromosome 6 at a position of 52.03% of the distance from the centromere, while the Sox17 gene was assigned to chromosome 5 on the region of 20.17% from centromere.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 35 (2000), S. 4477-4484 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The process and wear behavior of monolithic SiC and 10 vol. % short carbon fiber-SiC matrix (C-SiC) composite have been studied. The results indicate that, among ethyl alcohol, acetone, n-hexane and n-octyl alcohol, n-octyl alcohol was the most effective dispersing agent in dispersing both SiC powder and short carbon fiber. Among AlN, Al2O3, B4C, graphite, AlN/B4C, AlN/graphite, B4C/graphite and Al2O3/B4C, the most effective sintering aid for the fabrication of SiC and C-SiC composite was a mixture of 2 wt% AlN and 0.5 wt% graphite. The monolithic SiC hot-pressed at 2100°C exhibited higher density but lower flexural strength than those hot-pressed at 2000°C due to a grain growth effect. For the C-SiC composite, both density and strength of the composite hot-pressed at 2100°C were generally higher than those hot-pressed at 2000°C. The density and strength of C-SiC composite were lower than those of monolithic SiC under the same hot pressing conditions due to a higher porosity level in the composite. When monolithic SiC slid against C-SiC composite, the weight losses of SiC and the composite were each less than that of self-mated SiC or self-mated C-SiC. In the self-mated SiC tribosystem, a mechanically stable film could not be established, resulting in an essentially constant wear rate. When sliding against C-SiC, a thin, smooth and adherent debris film was quickly formed on the SiC surface, resulting in a lower wear.
    Type of Medium: Electronic Resource
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