370 research outputs found

    The Effects of Malonic Acid Derivatives and Acetic Acid Derivatives as Coadsorbents on the Photovoltaic Performance of Dye-Sensitized Solar Cells

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    The effects of malonic acid derivatives and acetic acid derivatives as coadsorbents on the photovoltaic performance of D908 dye-sensitized nanocrystalline TiO 2 solar cells were investigated. Each of phenylmalonic acid (PMA) and cyclopentylacetic acid (CPEAA) coadsorptions was revealed to improve both the photocurrent and the photovoltage of the solar cells. The improved photocurrent was probably due to the suppression of self-quenching of the excited electrons in the dyes by coadsorption of PMA or CPEAA on the TiO 2 that increased in the electron-injection yields from the dye to the TiO 2 . The improved photovoltage was probably due to suppression of recombination between the injected electrons and I 3 − ions on the TiO 2 surface. ATR-FTIR spectroscopy indicated that PMA or CPEAA coadsorption increased the content of bound dye on the TiO 2 surface. This result suggests that PMA or CPEAA coadsorption improved the photocurrent of the solar cells. Electrochemical impedance spectroscopy indicated that PMA or CPEAA coadsorption on the TiO 2 surface increased the charge recombination resistance (R2) and decreased the diffusion resistance in the electrolyte (R3). These results suggest that the coadsorption of PMA or CPEAA on the TiO 2 may improve its photovoltage and photocurrent

    Changes in dopamine D2 and GluR-1 glutamate receptor mRNAs in the rat brain after treatment with phencyclidine.

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    In situ hybridization of slide-mounted brain sections from rats subjected to acute and chronic phencyclidine treatment was carried out using synthetic oligonucleotides complementary to dopamine D2-receptor and non-N-methyl-D-aspartate (NMDA) glutamate-receptor-subunit (GluR-1) mRNAs. There was no significant difference in either the D2-receptor or the GluR-1 mRNA levels in any brain region of the acute phencyclidine (10 mg/kg)-treated and control groups. However, chronic administration of phencyclidine (10 mg/kg/day, 14 days) significantly decreased the dopamine D2-receptor mRNA level in the caudate-putamen (by 27%, P &#60; 0.01) and significantly increased the GluR-1 mRNA level in the prefrontal cortex (by 29%, P &#60; 0.001). These results suggest that the chronic pharmaco-behavioral effects of phencyclidine may involve expression of both dopamine- and non-NMDA glutamate-receptor mRNAs.</p

    A 1.5-Mb PAC/BAC Contig Spanning the Prader-Willi Syndrome Critical Region (PWCR)

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    Prader-Willi syndrome (PWS) is a multiple anomalies/mental retardation syndrome. The putative PWS gene(s) remains unknown, and its occurrence is based on genomic imprinting at chromosome 15q11-q13. We have constructed a 1.5- Mb, fine, physical map of PWS critical region (PWCR) between two markers, D15S9 and D15S174 at 15q11-q13. The map is composed of 32 PAC and 3 BAC clones without any gaps. By the PAC/BAC-end sequencing procedure, a total of 26 sequence tag site (STS) markers were newly generated, and 5 expressed sequence tags (ESTs) were mapped in the region. The contig map was verified by both STS and fluorescence in situ hybridization analyses. Our map has higher resolution, compared with a previous YAC-based map of PWCR. It is useful for further genome analysis, especially on genomic imprinting of this region

    Ultraviolet Continuum Color Variability of Luminous Sloan Digital Sky Survey QSOs

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    We examine whether the spectral energy distribution of UV continuum emission of active galactic nuclei changes during flux variation. We used multi-epoch photometric data of QSOs in the Stripe 82 observed by the SDSS Legacy Survey and selected 10 bright QSOs observed with high photometric accuracies, in the redshift range of z = 1.0-2.4 where strong broad emission lines such as Ly\alpha and CIV do not contaminate SDSS filters, to examine spectral variation of the UV continuum emission with broadband photometries. All target QSOs showed clear flux variations during the monitoring period 1998-2007, and the multi-epoch flux data in two different bands obtained on the same night showed a linear flux-to-flux relationship for all target QSOs. Assigning the flux in the longer wavelength to the x-axis in the flux-to-flux diagram, the x-intercept of the best-fit linear regression line was positive for most targets, which means that their colors in the observing bands become bluer as they become brighter. Then, the host-galaxy flux was estimated on the basis of the correlation between the stellar mass of the bulge of the host galaxy and the central black hole mass. We found that the longer-wavelength flux of the host galaxy was systematically smaller than that of the fainter extension of the best-fit regression line at the same shorter-wavelength flux for most targets. This result strongly indicates that the spectral shape of the continuum emission of QSOs in the UV region usually becomes bluer as it becomes brighter. We found that the multi-epoch flux-to-flux plots could be fitted well with the standard accretion disk model changing the mass accretion rate with a constant black hole mass for most targets. This finding strongly supports the standard accretion disk model for UV continuum emission of QSOs.Comment: 43 pages, 31 figures, accepted for publication in Ap
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