1,024 research outputs found

    Field-induced water electrolysis switches an oxide semiconductor from an insulator to a metal

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    Here we demonstrate that water-infiltrated nanoporous glass electrically switches an oxide semiconductor from an insulator to metal. We fabricated the field effect transistor structure on an oxide semiconductor, SrTiO3, using 100%-water-infiltrated nanoporous glass - amorphous 12CaO*7Al2O3 - as the gate insulator. For positive gate voltage, electron accumulation, water electrolysis and electrochemical reduction occur successively on the SrTiO3 surface at room temperature, leading to the formation of a thin (~3 nm) metal layer with an extremely high electron concentration of 10^15-10^16 cm^-2, which exhibits exotic thermoelectric behaviour.Comment: 21 pages, 12 figure

    Development of Resistive Electrode Gas Electron Multiplier (RE-GEM)

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    We successfully produced Resistive-Electrode Gas Electron Multiplier (RE-GEM) which has resistive electrodes instead of the metal ones which are employed for the standard GEM foils. RE-GEM has a resistive electrode of 25 micron-thick and an insulator layer of 100 micron-thick. The hole structure of RE-GEM is a single conical with the wider and narrower hole diameters of 80 micron and 60 micron, respectively. A hole pitch of RE-GEM is 140 micron. We obtained the maximum gain of about 600 and the typical energy resolution of about 20% (FWHM) at an applied voltage between the resistive electrodes of 620 V, using a collimated 8 keV X-rays from a generator in a gas mixture of 70% Ar and 30% CO2 by volume at the atmospheric pressure. We measured the effective gain as a function of the electric field of the drift region and obtained the maximum gain at an drift field of 0.5 kV/cm

    On the Two q-Analogue Logarithmic Functions

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    There is a simple, multi-sheet Riemann surface associated with e_q(z)'s inverse function ln_q(w) for 0< q < 1. A principal sheet for ln_q(w) can be defined. However, the topology of the Riemann surface for ln_q(w) changes each time "q" increases above the collision point of a pair of the turning points of e_q(x). There is also a power series representation for ln_q(1+w). An infinite-product representation for e_q(z) is used to obtain the ordinary natural logarithm ln{e_q(z)} and the values of sum rules for the zeros "z_i" of e_q(z). For |z|<|z_1|, e_q(z)=exp{b(z)} where b(z) is a simple, explicit power series in terms of values of these sum rules. The values of the sum rules for the q-trigonometric functions, sin_q(z) and cos_q(z), are q-deformations of the usual Bernoulli numbers.Comment: This is the final version to appear in J.Phys.A: Math. & General. Some explict formulas added, and to update the reference

    On the Origin of Broad Fe K alpha and Hi H alpha Lines in AGN

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    We examine the properties of the Fe emission lines that arise near 6.4 keV in the ASCA spectra of AGN. Our emphasis is on the Seyfert 1 galaxies where broad and apparently complex Fe K alpha emission is observed. We consider various origins for the line but focus on the pros and cons for line emitting accretion disk models. We develop a simple model of an illuminated disk capable of producing both X-ray and optical lines from a disk. The model is able to reproduce the observed Fe K alpha FWHM ratio as well as the radii of maximum emissivity implied by the profile redshifts. The overall profile shapes however do not fit well the predictions of our disk illumination model nor do we derive always consistent disk inclinations for the two lines. We conclude that the evidence for and against an accretion disk origin for the Fe K alpha emission is equal at best. The bulk of the data requires a very disparate set of line fits which shed little light on a coherent physical model. We briefly consider alternatives to disk emission models and show that a simple bicone model can reproduce the FE line profiles equally well.Comment: 29 pages, 6 tables, 6 figures. Submitted for publication in the Astrophysical Journal part

    A 3 dimensional diagnostic diagram for Seyfert 2s: probing X-ray absorption and Compton thickness

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    We present and discuss a "3-dimensional" diagnostic diagram for Seyfert2 galaxies obtained by means of X-ray and [OIII] data on a large sample of objects (reported in the Appendix). The diagram shows the Kalpha iron line equivalent width as a function of both the column density derived from the photoelectric cutoff and the 2-10 keV flux normalized to the [OIII] optical line flux (the latter corrected for extinction and assumed to be a true indicator of the source intrinsic luminosity). We find that the hard X-ray properties of type 2 objects depend on a single parameter, the absorbing column density along the line of sight,in accordance with the unified model. The diagram can be used to identify Compton thick sources and to isolate and study peculiar objects. From this analysis we have obtained a column density distribution of Seyfert 2 galaxies which is thought to be a good approximation of the real distribution. A large population of heavily absorbed objects is discovered, including many Compton thick candidates. Our results indicate that the mean Log Nh/cm^(-2)in type 2 Seyferts is 23.5 and that as much as 23-30% of sources have Nh > 10^24 cm^(-2).Comment: 33 pages, 3 figures, to be published in ApJ Sup

    Clinical and Genetic Characteristics of 18 Patients from 13 Japanese Families with CRX-associated retinal disorder: Identification of Genotype-phenotype Association

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    Inherited retinal disorder (IRD) is a leading cause of blindness, and CRX is one of a number of genes reported to harbour autosomal dominant (AD) and recessive (AR) causative variants. Eighteen patients from 13 families with CRX-associated retinal disorder (CRX-RD) were identified from 730 Japanese families with IRD. Ophthalmological examinations and phenotype subgroup classification were performed. The median age of onset/latest examination was 45.0/62.5 years (range, 15–77/25–94). The median visual acuity in the right/left eye was 0.52/0.40 (range, −0.08–2.00/−0.18–1.70) logarithm of the minimum angle of resolution (LogMAR) units. There was one family with macular dystrophy, nine with cone-rod dystrophy (CORD), and three with retinitis pigmentosa. In silico analysis of CRX variants was conducted for genotype subgroup classification based on inheritance and the presence of truncating variants. Eight pathogenic CRX variants were identified, including three novel heterozygous variants (p.R43H, p.P145Lfs*42, and p.P197Afs*22). A trend of a genotype-phenotype association was revealed between the phenotype and genotype subgroups. A considerably high proportion of CRX-RD in ADCORD was determined in the Japanese cohort (39.1%), often showing the mild phenotype (CORD) with late-onset disease (sixth decade). Frequently found heterozygous missense variants located within the homeodomain underlie this mild phenotype. This large cohort study delineates the disease spectrum of CRX-RD in the Japanese population

    The Cherenkov Correlated Timing Detector: Beam Test Results from Quartz and Acrylic Bars

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    Several prototypes of a Cherenkov Correlated Timing (CCT) Detector have been tested at the KEK-PS test beam line. We describe the results for Cherenkov light yields and timing characteristics from quartz and acrylic bar prototypes. A Cherenkov angle resolution is found to be 15 mrad at a propagation distance of 100 cm with a 2 cm thick quartz bar prototype.Comment: Presented at the RICH95 workshop, Uppsala, Sweden, June/95. H. Kichimi corresponding author. 5 pages with 9 figures. LaTex source files and postscript figures compressed and uuencoded belo

    Genetic Spectrum of EYS-associated Retinal Disease in a Large Japanese Cohort: Identification of Disease-associated Variants with Relatively High Allele Frequency

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    Biallelic variants in the EYS gene are a major cause of autosomal recessive inherited retinal disease (IRD), with a high prevalence in the Asian population. The purpose of this study was to identify pathogenic EYS variants, to determine the clinical/genetic spectrum of EYS-associated retinal disease (EYS-RD), and to discover disease-associated variants with relatively high allele frequency (1%-10%) in a nationwide Japanese cohort. Sixty-six affected subjects from 61 families with biallelic or multiple pathogenic/disease-associated EYS variants were ascertained by whole-exome sequencing. Three phenotype groups were identified in EYS-RD: retinitis pigmentosa (RP; 85.94%), cone-rod dystrophy (CORD; 10.94%), and Leber congenital amaurosis (LCA; 3.12%). Twenty-six pathogenic/disease-associated EYS variants were identified, including seven novel variants. The two most prevalent variants, p.(Gly843Glu) and p.(Thr2465Ser) were found in 26 and twelve families (42.6%, 19.7%), respectively, for which the allele frequency (AF) in the Japanese population was 2.2% and 3.0%, respectively. These results expand the phenotypic and genotypic spectrum of EYS-RD, accounting for a high proportion of EYS-RD both in autosomal recessive RP (23.4%) and autosomal recessive CORD (9.9%) in the Japanese population. The presence of EYS variants with relatively high AF highlights the importance of considering the pathogenicity of non-rare variants in relatively prevalent Mendelian disorders

    Clinicopathological characteristics of patients with amyotrophic lateral sclerosis resulting in a totally locked-in state (communication Stage V)

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    In the present study, we performed a comprehensive analysis to clarify the clinicopathological characteristics of patients with amyotrophic lateral sclerosis (ALS) that had progressed to result in a totally locked-in state (communication Stage V), in which all voluntary movements are lost and communication is impossible. In 11 patients, six had phosphorylated TAR DNA-binding protein 43 (pTDP-43)-immunoreactive (ir) neuronal cytoplasmic inclusions (NCI), two had fused in sarcoma (FUS)-ir NCI, and three had copper/zinc superoxide dismutase (SOD1)-ir NCI. The time from ALS onset to the need for tracheostomy invasive ventilation was less than 24 months in ten patients. Regardless of accumulated protein, all the patients showed common lesions in the pallido–nigro–luysian system, brainstem reticular formation, and cerebellar efferent system, in addition to motor neurons. In patients with pTDP-43-ir NCI, patients with NCI in the hippocampal dentate granule neurons (DG) showed a neuronal loss in the cerebral cortex, and patients without NCI in DG showed a preserved cerebral cortex. By contrast, in patients with FUS-ir NCI, patients with NCI in DG showed a preserved cerebral cortex and patients without NCI in DG showed marked cerebral degeneration. The cerebral cortex of patients with SOD1-ir NCI was preserved. Together, these findings suggest that lesions of the cerebrum are probably not necessary for progression to Stage V. In conclusion, patients with ALS that had progressed to result in communication Stage V showed rapidly-progressed symptoms, and their common lesions could cause the manifestations of communication Stage V

    Measurement of Inclusive Production of Neutral Pions from Upsilon(4S) Decays

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    Using the Belle detector operating at the KEKB e+e- storage ring, we have measured the mean multiplicity and the momentum spectrum of neutral pions from the decays of the Upsilon(4S) resonance. We measure a mean of 4.70 +/- 0.04 +/- 0.22 neutral pions per Upsilon(4S) decay.Comment: 15 pages, 4 figs. Submitted to Phys.Rev.
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