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  • 1
    Electronic Resource
    Electronic Resource
    Determination of Panthenol, Cholecalciferol and Tocopherol in Cosmetic Products by Gas Chromatography-Mass Spectrometry in SIM Mode (1999)
    Dordrecht, The Netherlands : Blackwell Science Ltd
    International journal of cosmetic science 21 (1999), S. 0 
    Details
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A novel simple method to detect vitamins in cosmetic products by gas chromatography-mass spectrometry (GC-MS) has been developed. Three vitamins (panthenol, cholecalciferol and tocopherol) were used for this study. Vitamins were prepared by dissolving in tetrahydrofuran (ThF), and silylated with bis-trimethylsilyltri-fluoroacetamide- trichloromethylsilane (BSTFA). Silylated vitamins were separated on a fused-silica capillary column coated with DB-5. The identification of each vitamin was accomplished by retention time and mass spectrum library search with a computer, and the quantitation was made in the selected-ion monitoring (SIM) mode of GC-MS. SIM mode had given sensitivity to determine 50 pg of panthenol, 285 pg of cholecalciferol and 130 pg of tocopherol. Linearity was maintained over the range 0.005–0.20% for each vitamin. Each cosmetic product (i.e. hair tonic and lotion) was found to contain amounts of the vitamins. This method was sensitive and gave 77.5–99.9% recovery of each vitamin from these cosmetic products. From these results, we concluded that silylation with BSTFA followed by GC-MS analysis allows the simple, convenient and exact determination of panthenol, cholecalciferol and tocopherol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1467-2494.1999.181685.x
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  • 2
    Electronic Resource
    Electronic Resource
    Electroluminescence at Si band gap energy based on metal–oxide–silicon structures (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 8793-8795 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Room-temperature electroluminescence corresponding to Si band gap energy from metal–oxide–semiconductor structures on both p-type and n-type Si is observed. With very thin oxide grown by rapid thermal oxidation, the metal–oxide–semiconductor structures behave like light emitting diodes. Luminescence is observed under forward bias even with a current density as low as 0.67 A/cm2. The physical reason for the electroluminescence is discussed and attributed to the localized wave function that leads to the spread of momentum. As a result, the spread momentum causes the electron–hole radiative recombination to occur relatively easily. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373612
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal characteristics of matrix-addressed liquid-crystal display (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 1055-1062 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermal characteristics of matrix-addressed smectic liquid-crystal cells are studied using the temperature dependence of the resistance of the heater and detector lines and compared to analytic solutions. The cell behavior is most strongly affected by the thermal properties of the substrate near the liquid crystal if the heater is at that interface. Cell features further away from the heater have a smaller influence. The cell power efficiency improves if the thermal flow through the substrate is reduced relative to the liquid crystal. The cell addressing speed can be increased if the substrate has two layers composed of a thin insulator on a conducting layer. Increasing the insulator thickness improves efficiency but reduces speed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.334547
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  • 4
    Electronic Resource
    Electronic Resource
    Solid phase regrowth of low temperature Be-implanted GaAs (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 57 (1985), S. 1022-1028 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Infrared reflection and transmission measurements were used to study the thermally induced regrowth of (100) oriented, Be-implanted GaAs samples. The samples used in this study were implanted at low temperature (−100 °C) with 250-keV Be ions to a fluence of 6×1015 cm−2. The samples were postannealed at temperatures ranging from 100 to 550 °C. Isochronal and isothermal annealing at a series of temperatures between 180 and 240 °C were performed. Infrared reflection spectra were analyzed by using a three or four layer dielectric model. Analysis of the annealing data suggests that an amorphous layer first anneals to a second metastable amorphous state and then becomes a damaged crystalline layer after annealing at 220 °C for 12 h. The observed regrowth is not by a simple epitaxial process. After annealing at 400 °C for 1 h, the damage in the layer is reduced sufficiently for the refractive index to recover almost to the preimplantation value. On annealing at 450 °C free carriers are observed. From the measured average regrowth rate for the amorphous layer at various anneal temperature, an effective activation energy is estimated to be about 1.45 eV. This compares with activation energies of 2.3 eV for Si and 2.0 eV for Ge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.334542
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  • 5
    Electronic Resource
    Electronic Resource
    Correlation between Si–H/D bond desorption and injected electron energy in metal–oxide–silicon tunneling diodes (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 637-639 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Metal–oxide–silicon tunneling diodes with SiO2/Si interface passivated by hydrogen or deuterium are stressed under various constant current conditions. When the energy of injected electrons exceeds a threshold value (∼3 eV), both hydrogen and deuterium passivated devices reveal similar soft breakdown behaviors. On the contrary, when the injected electrons with low energy (〈3 eV) at high current density stress, a giant isotope effect is observed in the deuterated devices due to the resonance between the Si–D bond bending mode and the transverse optical phonon of bulk silicon. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1343477
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  • 6
    Electronic Resource
    Electronic Resource
    Carrier lifetime measurement on electroluminescent metal–oxide–silicon tunneling diodes (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 2264-2266 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temporal response of the electroluminescence at the Si band gap energy from a metal–oxide–silicon (MOS) tunneling diode is used to characterize the minority carrier lifetime near the Si/SiO2 interface. The temporal responses reveal that the Shockley–Read–Hall (SRH) recombination lifetimes are 18 and 25.8 μs for the rising and falling edges, respectively, and that the ratio for SRH, radiative, and Auger recombinations is 1:0.196:0.096 at injection current density of 39 A/cm2. The investigation shows that the electroluminescence of the MOS tunneling diode can be significantly increased by reducing the number of the nonradiative recombination centers. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1405429
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  • 7
    Electronic Resource
    Electronic Resource
    Enhanced reliability of electroluminescence from metal–oxide–silicon tunneling diodes by deuterium incorporation (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 1397-1399 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The reliability of electroluminescence from metal–oxide–silicon (MOS) tunneling diodes was improved by the incorporation of deuterium. The deuterium was incorporated by the deuterium prebake and the postoxide deuterium annealing. At constant current stress of 100 mA, a deuterium-treated n-channel MOS tunneling light-emitting diode shows that the integrated light emission intensity increases slightly about 6% after 10 000 s operation, while the hydrogen-treated device shows a 30% decrease of the integrated light emission intensity. The hydrogen release by the electrons tunneling from the gate electrode to Si and the formation of interface defects are responsible for the degradation of light output in the hydrogen-treated samples. An annealing model is also given to explain the slight increase of light output in the deuterium-treated samples. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1353817
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  • 8
    Electronic Resource
    Electronic Resource
    Temperature dependence of the electron–hole-plasma electroluminescence from metal–oxide–silicon tunneling diodes (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 1111-1113 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature performance of metal–oxide–silicon tunneling light-emitting diodes was studied. An electron–hole-plasma model can be used to fit all the emission spectra from room temperature to 98 K. At constant voltage bias in the accumulation region, the normalized integral emission intensity slightly increases at low temperature with activation energy as low as 12 meV. From room temperature down to 98 K, the extracted band gaps are ∼80 meV lower than the value of Varshni equation, and the linewidth drops from 65 to 30 meV. The transverse optical and longitudinal optical phonons are involved in the light-emission process due to the reduction of extracted band gaps and the resemblance between electroluminescence and photoluminescence spectra at similar temperature. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1289491
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  • 9
    Electronic Resource
    Electronic Resource
    Room-temperature electroluminescence from electron-hole plasmas in the metal–oxide–silicon tunneling diodes (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 1516-1518 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An electron-hole plasma recombination model is used to fit the room-temperature electroluminescence from metal–oxide–silicon tunneling diodes. The relatively narrow line shape in the emission spectra can be understood by the quasi-Fermi level positions of electrons and holes, which both lie in the band gap. This model also gives a narrower band gap than that of bulk silicon. The surface band bending in the Si/oxide interface is responsible for this energy gap reduction. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126081
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  • 10
    Electronic Resource
    Electronic Resource
    Conditional loss of TGF-β signalling leads to increased susceptibility to gastrointestinal carcinogenesis in mice (2002)
    Oxford UK : Blackwell Science Ltd.
    Alimentary pharmacology & therapeutics 16 (2002), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Downregulation of TGF-β receptors is implicated in colon cancer development. Inactivation of either of the two transmembrane serine/threonine kinases, TGF-β1 types I/II receptors, is now implicated in carcinogenesis, especially gastrointestinal carcinogenesis.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:We generated transgenic mice, called pS2–dnRII or ITF–dnRII, of which the dominant negative mutant of the TGF-β type II receptor was expressed under the control of tissue-specific promoters, the pS2 promoter for stomach and ITF for intestine. They were either infected with H.pylori (ATCC 43504 strain, CagA+ and VacA+) or administered with azoxymethane to determine the significance of loss of TGF-β signalling in gastrointestinal carcinogenesis.〈section xml:id="abs1-3"〉〈title type="main"〉Results:Gastric adenocarcinoma developed in pS2–dnRII mice, whereas only chronic active gastritis was noted in wild-type littermates after 36 weeks of H.pylori infection. Mice lacking in TGF-β signalling specifically in the stomach showed a significantly higher proliferation cell nuclear antigen-labelling index when infected with H.pylori than wild-type littermates (P 〈 0.01). Development of colonic aberrant crypt foci was provoked in mice by intraperitoneal injections of azoxymethane, and ITF–dnRII mice showed significantly higher incidences of ACF and colon cancers than wild-type littermates.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:Maintaining normal TGF-β signalling in the gastrointestinal tract seems to be important either for preventing abnormal mucosal proliferation, or for suppressing or retarding carcinogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.16.s2.3.x
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