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The aim of the study was to evaluate the oral environment and the taste function of Japanese HIV-infected patients treated with antiretroviral therapy. Their median age of 73 patients taking anti-HIV drugs was 46 years. The median period of taking anti-HIV drugs was 30 months. The oral condition was evaluated by measurement of oral moisture, amount of saliva secretion, the number of oral bacteria, presence of oral candida, a taste test, and the number of missing teeth. The levels of oral moisture and secreted saliva were significantly lower in the HIV-infected group than in the healthy volunteer (control) group. The HIV-infected group showed a more robust decrease in taste sensation than the control group. The number of missing teeth was significantly higher in the HIV-infected group than in the control group. Furthermore, all of the evaluated oral conditions were worse in the HIV-infected patients whose CD4+ T lymphocyte counts were less than 500/mm3 than in the control group. It became clear that the patients taking anti-HIV drugs, especially the CD4+ count < 500/mm3 group, had a deteriorated oral environment and dysgeusia, suggesting that the management of oral hygiene is necessary to maintain oral health, which leads to systemic health. [ABSTRACT FROM AUTHOR]

In dynamic nuclear polarization (DNP) experiments applied to organic solids for creating nonequilibrium, high 1H spin polarization, an efficient buildup of 1H polarization is attained by partially deuterating the material of interest with an appropriate 1H concentration. In such a dilute 1H spin system, it is shown that the 1H spin diffusion rate and thereby the buildup efficiency of 1H polarization can further be enhanced by continually applying radiofrequency irradiation for deuterium decoupling during the DNP process. As experimentally confirmed in this work, the electron spin polarization of the photoexcited triplet state is mainly transferred only to those 1H spins, which are in the vicinity of the electron spins, and 1H spin diffusion transports the localized 1H polarization over the whole sample volume. The 1H spin diffusion coefficients are estimated from DNP repetition interval dependence of the initial buildup rate of 1H polarization, and the result indicates that the spin diffusion coefficient is enhanced by a factor of 2 compared to that without 2H decoupling. [ABSTRACT FROM AUTHOR]

The application of ion scattering spectroscopy (ISS) to the in situ measurement of the surface potential developed on an insulator surface under positive ion irradiation was investigated. The ISS spectra measured for a MgO film of 600 nm thickness on a Si substrate by the irradiation of 950 eV He+ ions revealed that the surface is positively charged by approximately 180 V. For accurate measurement of the surface potential, a correction to take into account the angular deflection of primary ions induced by the high surface potential is required. The dependence of the surface potential on the sample temperature revealed that no charging is induced above 700 °C, indicating that accumulated charges can be removed by heating to 700 °C. From the measurement of the ion-induced secondary electron yield using a collector electrode located in front of the sample surface, the surface potential and ion-induced secondary electron yield were found to be strongly affected by the experimental setup. Secondary electrons produced by the impact of slow positive secondary ions, the maximum energy of which corresponds to the surface potential, play an important role when the bias voltage applied to the collector electrode is positively high for the present experimental setup. The surface potential developed on the surface of MgO films of 600 and 200 nm thickness was measured in situ, revealing that the amount of accumulated charges and the time required to attain the steady state of charging are slightly dependent on the beam current of primary ions and strongly dependent on the thickness of the MgO film. The present results confirmed that the application of ISS has high potential for investigating charging phenomena and the secondary electron emission from insulator surfaces under positive ion irradiation. [ABSTRACT FROM AUTHOR]

ZnS and ZnMgS layers have been grown onto GaP substrates by molecular beam epitaxy (MBE). The key parameters of the growth are a high substrate temperature and a high sulfur (S) beam pressure. The S beam pressure was typically 1×10[sup -2] Pa, which was more than one order of magnitude larger than in conventional MBE of ZnS. Using the high S beam pressure, large ZnS growth rate of 0.3–1.0 μm/h could be obtained even at 490 °C. The growth rate was limited by the Zn supply. Optimization of the S beam pressure reduces the full width at half maximum (FWHM) of the (400) double-crystal x-ray rocking curve (DCXRC). For a 2.1-μm-thick ZnS layer the width can be reduced to 400 arcsec. The low temperature photoluminescence (PL) spectra show sharp excitonic emissions including the free exciton emission. ZnMgS layers were grown onto ZnS buffer layers. The ZnMgS layers as well show good crystal and optical qualities. The FWHM of DCXRC of the 1.5-μm-thick Zn[sub 0.83]Mg[sub 0.17]S layer is 650 arcsec, which is comparable to the FWHM of a ZnS layer of similar thickness. The low temperature PL of the ZnMgS layer is dominated by a strong excitonic emission. The band gap of Zn[sub 1-x]Mg[sub x]S is estimated from reflection spectra. For x=0.20, the band gap is 3.974 eV. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the electrical and optical properties of the phosphorous- and boron-doped hydrogenated amorphous silicon (a-Si:H) films deposited by microwave electron-cyclotron-resonance (ECR) plasma discharge. Schematic configuration of the microwave ECR plasma discharge system; Deposition conditions; Measurement of the conductivities of both the doped a-Si:H films.

Presents information on a study which investigated defect states in zinc (Zn) selenium (Se) single crystals induced by ⊃60Co ϒray irradiation with deep-level transient spectroscopy and optical deep-level transient spectroscopy. Changes in junction characteristics; Discussion on the deep levels in Zn-annealed ZnSe; Irradiation effects on electron traps; Irradiation effects on hole traps.

Abstract This case report describes a follow up investigation of a patient with impaired word discrimination due to mitochondrial encephalopathy with lactic acidosis and stroke-like syndrome (MELAS) using pro ton [...]