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Tsuyoshi Sekizuka, Kentaro Itokawa, Rina Tanaka, Masanori Hashino, Koji Yatsu, Makoto Kuroda Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, 162-8640, JapanCorrespondence: Makoto Kuroda, Pathogen Genomics Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjyuku, Tokyo, 162-8640, Japan, Tel +81-3-5285-1111, Fax +81-3-5285-1166, Email makokuro@niid.go.jpPurpose: Urban wastewater treatment plant (WWTP) effluents, even with proper treatment, may cause antimicrobial resistance (AMR) burden, with a high frequency of acquired antimicrobial resistance genes (ARGs). The dissemination of ARGs into the environment increases the risk of infectious diseases; however, there is little direct evidence regarding their epidemiological effects. This study aimed to assess effluents from urban WWTPs around the Tama River and Tokyo Bay using metagenomic analysis of (AMR) genes (ARGs) and heavy-metal resistance genes.Methods: Metagenomic DNA-seq analysis of water samples and resistome analysis were performed.Results: The most prevalent ARG was the sulfonamide resistance gene, sul1, followed by the quaternary ammonium compound resistance gene, qacE, suggesting that basic gene sets (sul1 and ∆qacE) in the class 1 integrons are the predominant ARGs. The aminoglycoside resistance genes, aadA and aph, and macrolide resistance genes, msr(E) and mph(E), were the predominant ARGs against each antimicrobial. blaOXA and blaGES were frequently detected, whereas the blaCTX-M cluster was faintly detected. Non-metric multidimensional scaling plot analysis and canonical correspondence analysis results suggested that marked differences in ARGs could be involved in the seasonal differences; qnrS2, aac(6’)-Ib, and mef(C) increased markedly in summer, whereas msr(E) was more frequently detected in winter. Heavy-metal (Hg and Cu) resistance genes (HMRGs) were significantly detected in effluents from all WWTPs.Conclusion: We characterized a baseline level of the environmental ARG/HMRG profile in the overall community, suggesting that environmental AMR surveillance, particularly in urban WWTPs, is a valuable first step in monitoring the AMR dissemination of bacteria from predominantly healthy individuals carrying notable ARG/Bs.Keywords: urban sewage, effluent, metagenomics, Enterobacteriaceae, ESBL, carbapenemase, heavy-metal resistance

A theoretical model of the x-ray responses of silicon surface-barrier (SSB) detectors was developed under a configuration of a widely used detector structure for plasma x-ray diagnostics. The model consisted of a signal contribution from thermally diffusing charge created in the field-free substrate region within a diffusion length from the depletion layer. This was accompanied signal contributions coming from charge created in the depletion layer. The model was found to predict a large signal contribution from the charge-diffusion effect on the SSB responses to high-energy x-rays.

Presents a study which proposed an analytical method based on a theoretical model for the x-ray energy responses of silicon surface-barrier detectors (SSB). Description of the model used in the study; Formulas and calculated results supporting SSB calibration data; Discussion of results.

A new theory on x-ray response is developed for settling the confusion on plasma x-ray analysis using silicon surface-barrier (SSB) detectors. In earlier studies, the influence of the thermal-diffusion charge on the x-ray energy response of SSB detectors was ignored. The SSB response is therefore analyzed using the thickness of the depletion layer.

Aims: The aim of this study was to investigate the association between normal tension glaucoma and the candidate disease locus glaucoma 1, open angle, B (GLC1B) on chromosome 2. There are many reports describing the results of association or linkage studies for primary open angle glaucoma (POAG), with GLC1B as one of the loci associated with normal or moderately elevated intraocular pressure. However, there are few reports about the association of genes or defined genomic regions with normal tension glaucoma, which is the leading type of glaucoma in Japan. The GLC1B locus is hypothesized to be a causative region for normal tension glaucoma. Methods: Genomic DNA was extracted from whole blood of normal tension glaucoma (n = 143) and healthy controls (n = 103) of Japanese origin. Results: Fifteen microsatellite markers within and/or near to the GLC1 B locus were genotyped, and their association with normal tension glaucoma was analysed. Two markers D2S2264 and D2S176 had significant positive associations. Conclusion: The D2S176 marker had the strongest significant association and it is located 24 kb from the nearest gene NCK2, which now becomes an important new candidate gene for future studies of its association with normal tension glaucoma. [ABSTRACT FROM AUTHOR]

Lighter particles streaming, dust charge fluctuation, and collisional effects on the dust-modes, viz., the dust-lower-hybrid (DLH) and dust-acoustic (DA) waves, have been examined analytically using fluid model. In the absence of dust charge fluctuation and collisional effects, two-stream instability of these modes occurs when the ion streaming velocity exceeds the parallel phase velocity of the respective mode. Moreover, if either ion or electron streaming velocity exceeds the wave parallel phase velocity, then the collisions of ions or electrons with neutral gas atoms/molecules give destabilizing effect on the dust-modes provided the dust charge fluctuation is negligible. Dust charge fluctuation gives the damping of either of these modes. It is found that charge fluctuation and collisional effects on the DA-mode are greater than those of the DLH-mode. Hence, the DLH-mode is more stable compared to the DA-mode. [ABSTRACT FROM AUTHOR]

In this paper we show the self-consistent evolution of an isolated density perturbation in models of tokamak scrape-off layer turbulence. Our purpose is to explain the possible mechanisms responsible for radial propagation of density perturbations observed in the scrape-off layer. Results of both two-dimensional numerical simulations and one-dimensional quasilinear modeling of the propagative events are presented, and shown to be consistent with many experimental observations. The role of sheath dissipation for front propagation and turbulent mixing is also addressed. [ABSTRACT FROM AUTHOR]

Under the international fusion cooperating research, ³He neutron detectors in the GAMMA 10 tandem mirror are calibrated by the use of a [sup 252]Cf spontaneous fission neutron source (8.96 × 10[sup 4]n/s). The calibration experiments are carried out with a "rail system" placed along the magnetic axis of the GAMMA 10 central-cell region, where hot ions in the plasma experiments with the bulk temperatures of ∼10 keV are produced. As compared to a previous neutron monitoring system with a BF[sub 3] detector in GAMMA 10, the present ³He systems are designed with about two orders-of-magnitude higher neutron-counting efficiency for analyzing a neutron emissivity from the plasmas in a single plasma discharge alone. Two ³He systems are installed near the middle and the end of the central cell so as to identify the central-cell hot-ion axial profile. The filling pressure of ³He, the effective length, and the diameter of the detector are designed as 5 bar, 300 mm, and 50 mm, respectively. The detector output spectra are carefully analyzed by the use of a preamplifier, a shaping amplifier, as well as a multichannel analyzer for each ³He detector. In the present article, the neutron-counting data from the two ³He detectors due to the on-axis [sup 252]Cf scan are interpreted in terms of the d[sup -2] intensity dependence (d being the distance between the detector and the neutron source) as well as the effects of the central-cell magnetic coils and the other machine structural components. [ABSTRACT FROM AUTHOR]

Temporal evolution of radial profiles of end-loss-ion currents, ion temperatures, and ion-confining potentials φ[sub c] is investigated in the GAMMA 10 tandem mirror by the use of our newly designed electrostatic ion-energy-spectrometer arrays. In tandem-mirror experiments, plasma-confining potentials produced by electron-cyclotron heatings (ECH's) play one of the most critical roles in the improvement of simple-mirror plasma confinement. For the observations of these confining potentials, the development of ion-diagnostics equipment providing clear energy spectra without disturbances from ECH produced energetic electrons is of essential importance, since conventional multigrided Faraday cup signals are seriously influenced by such incident electrons. Each spectrometer unit in our developed array has a specific structure with obliquely placed multiple grids with respect to the direction of the ambient lines of magnetic force for plasma confinement. The relation between the spatial profiles of end-loss-ion fluxes I[sub ELA] and those of φ[sub c] is investigated by the use of these newly designed ion-energy-spectrometer arrays installed in both end regions of GAMMA 10. The first remarkable finding of axisymmetric profiles of φ[sub c] having a good correlation with axisymmetric plugging distributions in I[sub ELA] along with the central-cell density n[sub c] increase is made; while, the contrary result without n[sub c] increase even during a plugging period is found with asymmetric profiles of φ[sub c] with asymmetric plugging profiles in I[sub ELA]. In the article, detailed data comparison between the two is reported by the use of each single-plasma discharge with the developed ion-spectrometer arrays. [ABSTRACT FROM AUTHOR]

For the purpose of end-loss-ion energy analyses in open-field plasmas, a newly developed electrostatic ion-energy spectrometer is proposed on the basis of a "self-collection" principle for secondary-electron emission from a metal collector. The ion-energy spectrometer is designed with multiple grids for analyzing incident ion energies, and a set of parallelly placed metal plates with respect to lines of ambient magnetic forces in an open-ended device. One of the most important characteristic properties of this spectrometer is the use of our proposed principle of a "self-collection" mechanism due to E×B drifts for secondary electrons emitted from the grounded metal-plate collector by the use of no further additional magnetic systems except the ambient open-ended fields B. The proof-of-principle and characterization experiments are carried out by the use of a test-ion-beam line along with an additional use of a Helmholtz coil system for the formation of open magnetic fields similar to those in the GAMMA 10 end region. The applications of the developed ion-energy spectrometer for end-loss-ion diagnostics in the GAMMA 10 plasma experiments are demonstrated under the conditions with simultaneous incidence of energetic electrons produced by electron-cyclotron heatings for end-loss-plugging potential formation, since these electrons have contributed to disturb these ion signals from conventional end-loss-ion detectors. [ABSTRACT FROM AUTHOR]

Results of H[sub α] measurement in the GAMMA 10 tandem mirror are described, with a particular focus on the behavior of neutrals in the anchor minimum-B region. Recently a set of H[sub α] line-emission detector arrays was designed and installed in the anchor-cell, where the shape of the magnetic flux tube becomes flat and the cross section of plasma is elongated elliptically. The detector consists of H[sub α] interference filter, optical fiber, and photomultiplier with magnetic shield, and is absolutely calibrated by using a standard lamp. In standard ion-cyclotron-range-of-frequency heated, hot-ion-mode plasmas, detailed measurements of H[sub α] line-emission form the central-cell to the anchor-cell were carried out, and the dependence of the H[sub α] intensity on the quantity of gas puffing was investigated. The characteristic behavior of neutrals in the nonaxisymmetric anchor-cell is also discussed, based on the result of neutral transport simulation. [ABSTRACT FROM AUTHOR]

A method is proposed for obtaining radial profiles of both plasma ion (T[sub i]) and electron temperatures (T[sub e]) simultaneously using a semiconductor detector. This method for semiconductor T[sub i] diagnostics is proposed on the basis of an alternative "positive" use of a semiconductor "dead layer" as an energy-analysis filter. Filtering dependence of charge-exchange (cx) neutral particles from plasmas on the thickness on the order of a nanometer-thick SiO[sub 2] layer is used for analyzing T[sub i] in the range from hundreds to thousands of electron volts. Even under the circumstances of simultaneous incidence of such particles and x rays along the same lines of sight of a semiconductor detector array, it is found that the different dependence on their penetration lengths and deposition depths in semiconductor materials makes it possible to distinguish cx neutral particles for T[sub i] diagnostics from x rays for T[sub e] diagnostics. Experimental verification of this concept of the simultaneous T[sub i] and T[sub e] diagnostics is carried out in the GAMMA 10 tandem mirror by the use of a matrix-type semiconductor detector. The detector is characterized in terms of compact formation of six rows with different thicknesses of thin dead layers (SiO[sub 2]) on its surface. Each row has seven channels (columns) for measuring radiation profiles in the radial direction of plasmas so as to make tomographic reconstructions for attaining the actual emissivity profiles in the plasmas. These various SiO[sub 2] layers are proposed to be applied as "unbreakable ultrathin radiation-absorption filters" having various thicknesses to distinguish x rays from neutral particles simultaneously. [ABSTRACT FROM AUTHOR]

A gold film detector was developed in order to measure the plasma density profile by use of the gold neutral beam probe. The detector is a kind of neutral beam detector composed of a rectangular entrance collimator, two sets of grid plates, a gold thin film, a quartz backing, and a microcarbon coated copper plate. The secondary electrons emitted from the gold film were utilized for the neutral beam detection. The yield curves of the secondary electrons were measured as a function of the incident angle and electron energy in both cases of the gold neutral probing beam and ultraviolet ray injection. Time evolution of the plasma line density was measured by adjusting the incident angle and adding a beam chopping method. The result was in good agreement with the line density measured by a microwave interferometer. It was found that this film detector was quite useful in the viewpoint of simultaneous measurements of the electrostatic potential and plasma density profiles. [ABSTRACT FROM AUTHOR]

Examines the influence of the radial electric field on the trajectories of plug potential bounce ion in the tandem mirror. Radial drift of the bounce ion due to a discrepancy between the shapes; Control of the radial potential profile of the core plasma by adjustment of the radially separated endplate potentials; Effectiveness of the flattened radial potential profile in the decrease of the radial shift.

A formation mechanism of the plug potential in a tandem mirror is proposed. The orbits for ions, which are accelerated by the thermal barrier potential, are calculated numerically in a magnetic mirror field. A non-Maxwellian electron distribution function, which leads to a modified Boltzmann law, is assumed in order to determine the electrostatic potential profile. Monte Carlo simulation is carried out for ion dynamics to include the effects of Coulomb collisions and ion radial losses. It is found that the plug potential is formed under the condition that the ions trapped in the thermal barrier region are few. [ABSTRACT FROM AUTHOR]

Vacuum ultraviolet (VUV) and soft X-ray (SX) spectroscopic measurements are important means to diagnose radiation power loss, impurity ion densities and effective charge of confined plasma, Z[sub eff], in magnetically confined plasmas such as fusion plasmas. We have constructed space- and time-resolving flat-field VUV (150-1050 Å) and SX (20-350 Å) spectrographs by using aberration-corrected concave gratings with varied line spacing. Absolute calibration experiments have been conducted at the Photon Factory in the High Energy Accelerator Research Organization. Absolute sensitivities of the VUV and SX spectrographs have been obtained for the two (S and P) polarization geometries. Thus, absolute intensities of emission spectra from impurity ions can be measured together with their radial distributions in plasmas. The total radiation power was determined to be less than 6 kW within ±20% of error in our normal plasma operation. Density profiles of impurity ions were reduced by using absolute emissivities of impurity lines and a collisional-radiative model. Moreover, the value of Z[sub eff] is estimated to be 1.00 in the tandem mirror GAMMA 10 plasma. [ABSTRACT FROM AUTHOR]

Measurement of spectra in the wavelength range from vacuum ultraviolet (VUV) to soft x ray is an important means to diagnose impurity behavior in magnetically confined plasmas used in fusion plasmas. Recently, a space- and time-resolving flat-field grazing-incidence VUV spectrograph was constructed for the simultaneous observation of spatial, temporal, and spectral distributions of plasma radiation in the wavelength range of 150–1050 Å. Absolute calibration experiments were performed at beamline 11C and beamline 12A in the Photon Factory at the High Energy Acceleration Research Organization. The absolute sensitivity of the VUV spectrograph was measured under both P and S polarized light conditions. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The improvement of potential confinement was attained in the GAMMA 10 tandem mirror [Phys. Rev. Lett. 55, 939 (1985); Proceedings of the 13th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Washington, 1990 (Intemational Atomic Energy Agency, Vienna, 1991), Vol. 2, p. 539] by axisymmetrization of heating systems for the plasma production, heating, and potential formation. A significant increase of the density and diamagnetism by the potential confinement was observed. In the previous experiment, it was difficult to increase the central cell density higher than 2.7 × 10[sup 18]m[sup -3] One of the possible mechanisms is the density clamping due to the eigenmode formation ofthe ion-cyclotron-range of frequency (ICRF) waves in the axial direction. With high harmonic ICRF waves (RF3), the experiments to overcome this problem have been performed. In preliminary experiments with RF3 and NBI the maximum density of 4x 10[sup 18]m[sup -3] was attained. [ABSTRACT FROM AUTHOR]

The first results of simultaneous observations of temporally and spatially resolved electron temperatures (T[sub e]) in both circularly shaped central-cell and elliptically shaped anchor regions are reported in the GAMMA 10 tandem mirror. A data set is provided using a novel matrix-type x-ray semiconductor detector. The detector has seven “matrix columns” for the measurement of plasma x-ray profiles along with six “matrix rows” for simultaneous analyses of six different x-ray-energy ranges by the fabrication of six different thicknesses of SiO[sub 2] semiconductor surface layers from 1 to 495 nm as ultrathin and unbreakable “x-ray absorption filters.” Such a matrix idea enables us to analyze x-ray tomography data in the T[sub e] region down to a few tens of eV. Simultaneous application of the x-ray detectors in the central-cell and the anchor region gives information on not only detailed electron behavior in each region but also the mutually communicating relation between the two regions: The role of the anchor-region plasmas in magnetohydrodynamic plasma stabilization in the central-cell plasmas is confirmed by the data from these detailed simultaneous electron observations. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A probe wave system was constructed for studying the excitation of the Alfve´n ion cyclotron (AIC) modes in the anchor cell of the GAMMA 10 tandem mirror. In the central cell, the AIC modes are spontaneously excited as axial eigenmodes due to the strong temperature anisotropy. In the anchor cell, the AIC modes were not observed though the anisotropy is the same as in the central cell. The axial profiles of the magnetic field strength and plasma parameters in the anchor cell are different from those in the central cell. Eigenmodes are excited externally in the AIC frequency range by injecting probe waves. This suggests the AIC modes are unstable in the anchor cell and grow to the detectable level when boundary conditions are realized. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

In the GAMMA10 tandem mirror, a strong ion cyclotron range of frequency heating is performed. As a result of the heating, the Alfve´n ion cyclotron (AIC) modes are spontaneously excited due to the strong temperature anisotropy. The AIC modes in the GAMMA10 are excited as the axial eigenmodes and detected at the whole of the device. In the recent experiments, the clear standing wave structure is observed with the magnetic probe measurements. Characteristics of the AIC modes and the measurement of the axial profile are presented. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Newly designed spectrometer arrays for ion-energy-spectrum observations are proposed and constructed in both end regions of the GAMMA 10 tandem mirror so as to obtain two dimensionally resolved radial profiles of end-loss-ion fluxes I[sub ELA], ion temperatures, and ion-confining potentials &fgr;[sub c] by the use of a single plasma discharge alone. Each spectrometer unit in the array has a specific structure with obliquely placed multiple grids with respect to the direction of the ambient plasma-confining magnetic fields. This structure is proposed to obtain precise ion-energy spectra without the disturbance of simultaneously incident energetic electrons into the array, since widely distributed “multigridded Faraday cup” signals have significant electron disturbances on ion spectra even if over a few tens of kV are applied to the electron-repeller grid. In tandem-mirror experiments, plasma-confining potentials produced by electron cyclotron heatings play one of the most critical roles in the improvement of simple-mirror confinement. Thus, diagnostics of these confining potentials using clear ion spectra are of essential importance. From these motivations, the spatial distribution details and relations of &fgr;[sub c] and I[sub ELA] are investigated by the use of the novel ion spectrometers. Axisymmetric profiles of &fgr;[sub c] are found to have a good correlation with axisymmetric plugging distributions in I[sub ELA]. These are consistently interpreted in terms of the Pastukhov theory of the relation of &fgr;[sub c] with I[sub ELA]. Information on such specific spectrometer arrays would contribute to researchers in a wide variety of plasma devices, who employ analyzers for flux, temperature, and potential diagnostics under energetic plasma circumstances. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

For the purpose of investigating fusion-produced neutron effects on semiconductor x-ray detectors, detection characteristics of x-ray tomography detectors used before and after deuterium–tritium (DT) and/or DD fusion-plasma experiments in the Joint European Torus (JET) tokamak are studied using synchrotron radiation from a 2.5 GeV positron storage ring at the Photon Factory. Degradations in the responses after neutron exposure into the detectors are found to have functional dependence on x-ray energy. Changes in the depletion thicknesses of the detectors are investigated by means of impedance analyses. The Fusion Neutronics Source (FNS) facility of the Japan Atomic Energy Research Institute is also employed for well calibrated DT fusion-produced neutron irradiation onto these semiconductor x-ray detectors. Recovery of the response degradation is found due to a method for supplying the operational bias to the degraded detector. Our theory is applied to interpret these detector characteristics under the irradiation of DT fusion-produced neutrons in the JET tokamak and the FNS facility. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]