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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
    Layer-resolved spin polarization in Sb overlayers on NiMnSb (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 7275-7277 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The magnetism of antimony overlayers on a ferromagnetic substrate is investigated by spin-polarized inverse photoemission and explained in terms of a spin-dependent envelope-function approximation (SDEFA). The atomic structure of the films, which were deposited by sputtering Sb onto a NiMnSb(001) substrate, is characterized by a unique combination of three features: (i) NiMnSb is a highly spin-polarized semi-Heusler alloy predicted to be halfmetallic, (ii) antimony is a semimetal, exhibiting a band structure reminiscent of indirect-gap semiconductors, and (iii) the small lattice mismatch ensures a well-controlled interface. Combined x-ray absorption spectroscopy and spin-polarized inverse photoemission yield a layer-resolved spin polarization decaying on a length scale of the order of 1 nm. The unusual range of the spin polarization in the paramagnetic overlayer is explained by considering the alloy–antimony interface as a spin-dependent perturbation potential and taking into account the low effective masses of the Sb conduction electrons (only about 0.1 for both electrons and holes). © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1357849
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  • 3
    Electronic Resource
    Electronic Resource
    Failure of exchange-biased low resistance magnetic tunneling junctions upon thermal treatment (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 217-220 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Transmission electron microscopy (TEM) and Rutherford backscattering spectroscopy (RBS) were used to characterize low resistance (100–1000 Ω μm2) tunneling junctions consisting of Ta/NiFe/Cu/NiFe/IrMn/CoFe/Al (6.6 and 7.7 Å)–oxide/CoFe/NiFe/Ta multilayers after annealing at temperatures ranging from 250 to 500 °C. The Al (7.7 Å) junction showed continual improvement in the magnetoresistance (MR) ratio when annealed up to 300 °C while the MR ratio of the Al (6.6 Å) junction dropped sharply above 250 °C in spite of the only 1 Å difference in the deposited thickness of aluminum metal prior to plasma oxidation. TEM measurement provided evidence that the annealing process improves, in general, structural uniformity in the insulation layer, but thermal treatment can also degrade junction performance at a relatively low temperature due to current leakage through the electrodes. Current leakage can be problematic for a junction whose insulation barrier may be too thin (less than ∼10 Å). Both RBS and TEM analyses indicated that the maximum annealing temperature of exchange biased junctions lies between 400 and 500 °C above which the multilayer structure in the pinned electrode is destroyed by interdiffusion. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1420770
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  • 4
    Electronic Resource
    Electronic Resource
    Interdiffusion in antiferromagnetic/ferromagnetic exchange coupled NiFe/IrMn/CoFe multilayer (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 1431-1435 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Auger electron spectroscopy (AES) and Rutherford backscattering spectroscopy (RBS) analysis were carried out in order to study the extent of interdiffusion during thermal treatment of the pinned electrode (Ta/NiFe/Cu/NiFe/IrMn/CoFe) of the magnetic tunneling junction. From the concentration profile results from RBS and AES, a significant amount of Mn–CoFe interdiffusion was observed when the sample was annealed at 200 °C–400 °C under vacuum. The multilayer was completely intermixed at 400 °C, losing the exchange bias interaction between the IrMn and CoFe layers. It was demonstrated that the migration of Mn was enhanced by the preferential oxidation of Mn on the surface. In fact, when a thin layer of Ta for oxidation protection was deposited on top of the electrode, the Mn diffusion was minimal up to 300 °C. Our experiment suggests that in actual magnetic tunneling junctions, the Mn diffusion to the insulation layer could be enhanced by the presence of the free oxygen radicals in the insulation layer produced during the plasma oxidation of the Al layer. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1427400
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  • 5
    Electronic Resource
    Electronic Resource
    The niobium doping effects on resistance degradation of strontium titanate thin film capacitors (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 1455-1457 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The rate of resistance degradation of thin (〈450 Å) niobium-doped strontium titanate polycrystalline films with platinum top electrodes and iridium bottom electrodes was investigated as a function of direct current (dc) voltages, temperature, Nb atomic fractions [Sr(Ti1−xNbx)O3+y, x=0, 0.001, 0.01, and 0.05, respectively], and capacitor areas (from 2.50×10−5 to 2.91×10−3 cm2). It was found that by increasing the amount of niobium, the resistance degradation rates were greatly reduced, but the leakage currents increased. Also, the degradation rates seemed fairly independent of the areas of the devices. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124723
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  • 6
    Electronic Resource
    Electronic Resource
    Fabrication of 0.1 μm gate aperture Mo-tip field-emitter arrays using interferometric lithography (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 3050-3052 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A fabrication process has been developed which enables us to make matrix-addressable Mo-tip field-emitter arrays (FEAs) with 0.1 μm gate aperture and 0.2 μm tip-to-tip distance. An interferometric lithography combined with a trilevel resist process which uses an imaging resist layer, a silicon oxide interlayer, and antireflective coating has been implemented to fabricate the periodic structure of the gated FEAs in an addressable matrix. The matrix-addressable FEAs have shown a turn-on voltage as low as 13 V and an emission current density of 17 mA/cm2 at a gate voltage of 30 V. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124061
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of niobium doping on the microstructure and electrical properties of strontium titanate thin films for semiconductor memory application (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 2123-2125 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Niobium doped strontium titanate [Sr(Ti1−xNbx)O3] thin films (≅40 nm) were deposited on Ir substrates using rf magnetron sputtering. The effect of Nb content (x=0, 0.001, 0.01, and 0.05) on the microstructure, dielectric constant, dielectric dispersion, and leakage current was studied. It was found that with increasing Nb content the dielectric constant decreased, probably owing to an observed decrease in grain size. The dielectric dispersion of all the Nb-doped ST films was lower than that of undoped ST film deposited at the same temperature and pressure. For the case of x=0.01, dispersion as low as 0.425% per decade was observed. The leakage current was found to increase slightly for x=0.001 and x=0.01, and drastically for the x=0.05 case. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124937
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  • 8
    Electronic Resource
    Electronic Resource
    Bias-assisted photoelectrochemical oxidation of n-GaN in H2O (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 81 (2002), S. 1029-1031 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Growth of gallium oxide on n-GaN was realized in H2O by bias-assisted photoelectrochemical (PEC) oxidation using Al as a counterelectrode instead of a Pt commonly used in the PEC process. Although the growth of the oxide was not observed at below 2 V, the initial oxide growth rate of 8.7 nm/min was shown at a bias of 15 V and ultraviolet light intensity of 300 mW/cm2. However, the growth rate lowered and oxide thickness was saturated to 340 nm. The saturated oxide thickness and initial growth rate were increased with the applied bias. The homogeneous oxide growth and near stoichiometric composition of Ga2O3 were observed in Auger electron spectroscopy analysis results. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1498863
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and structure determination of the adducts of the potent carcinogen 7,12-dimethylbenz[a]anthracene and deoxyribonucleosides formed by electrochemical oxidation: models for metabolic activation by one-electron oxidation (1992)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 114 (1992), S. 1863-1874 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00031a047
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  • 10
    Electronic Resource
    Electronic Resource
    IgE-mediated occupational asthma induced by herbal medicine, Banha (Pinellia ternata) (2001)
    Oxford, UK : Blackwell Science, Ltd
    Clinical & experimental allergy 31 (2001), S. 0 
    Details
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: There have been few reported cases of occupational asthma induced by Pinellia ternata (Banha), and the mechanism responsible for this type of asthma is still undetermined. We report a case of Banha-induced occupational asthma with IgE-mediated mechanism. The patient had positive skin responses to Banha extract and Banha-specific bronchial challenge elicited an early asthmatic response. The serum-specific IgE binding to Banha extract was detectable and completely inhibited with the additions of 0.1 µg/mL of Banha extract on ELISA inhibition. Seven IgE binding components to Banha extract (6.5, 22, 24, 32, 34, and 48 kDa) were detected using SDS–PAGE and immunoblot analysis. In conclusion, the results of this study suggest that P. ternata (Banha)-derived allergens are able to cause IgE-mediated bronchoconstriction in exposed workers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2222.2001.01067.x
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