780 research outputs found

    チテキカンキョウニオケルインタラクションシエンノタメノジッセカイコンテキストニンシキオヨビオウヨウ

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    We have observed Fe14+ (3s^2 ^1S_0 - 3s3p ^1P_1) and Fe15+ (3s ^2S1/2 - 3p ^2P_[3/2]) emissions from a LHD plasma with a space-resolved extreme-ultraviolet spectrometer. The observed intensity distributions against the viewing chord for the respective emissions are reconstructed to the emission flux distributions in the plasma against the normalized radius of the poloidal cross section with a maximum entropy method. Both of the emissions localize in the periphery region, and the Fe^[14+] emission is located outer side than that of Fe15+. We calculate the charge state distribution of Fe ions against the normalized radius assuming the ionization equilibrium at the electron temperature and density, which are measured by a Thomson scattering method. The calculated result is consistent with the experimental one

    Comparative Study of the Differences in Radiologic Results for Percutaneous Endoscopic Lumbar Foraminotomy and Microscopic or Micro-endoscopic Lumbar Foraminotomy

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    Objective Lumbar foraminal stenosis is a common pathology that causes back pain and radiculopathy. Percutaneous endoscopic lumbar foraminotomy (PELF) is a minimally invasive surgical procedure reported to be effective in the treatment of foraminal stenosis; however, no studies have been conducted that compare the on radiographic results of PELF and conventional techniques for the treatment of foraminal stenosis, such as microscopic foraminotomy and micro-endoscopic foraminotomy. This study aimed to report postoperative changes in the lumbar foraminal parameters on computed tomography (CT) after PELF and to compare the radiological efficacy of the PELF technique with that of the conventional techniques. Methods Radiographic evaluation of the neuroforamen was based on CT scans taken preoperatively and 3 months postoperatively in the PELF and conventional groups. The Japanese Orthopaedic Association (JOA) score for back pain, visual analog scale (VAS), and JOA back pain evaluation questionnaire (JOABPEQ) were evaluated preoperatively and at 3 months postoperatively in the PELF group. Results The PELF and conventional groups comprised 21 and 17 patients, respectively. In the PELF group, the JOA score, VAS of back pain, and JOABPEQ of low back pain showed significant improvement. There were significant increases in the foraminal area, superior foraminal width (SFW), and middle foraminal width (MFW). Additional radiological evaluation for patients who underwent microscopic or micro-endoscopic lumbar foraminotomy was almost equivalent. Conclusion Percutaneous endoscopic lumbar foraminotomy is a minimally invasive technique that is as effective as conventional techniques for the treatment of foraminal stenosis

    Space-resolved visible spectroscopy for two-dimensional measurement of hydrogen and impurity emission spectra and of plasma flow in the edge stochastic layer of LHD

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    A space-resolved visible spectrometer system has been developed for two-dimensional (2D) distribution measurements of hydrogen and impurity emission spectra and of plasma flow in the edge stochastic layer of Large Helical Device (LHD). Astigmatism of the spectrometer has been suppressed by introducing additional toroidal and spherical mirrors. A good focal image at the exit slit is realized in a wide wavelength range (75 nm) as well as in a wide slit height direction (26 mm) with a 300 grooves/mm grating. The capability of the spectrometer optical system for the 2D measurement and further possible improvements are discussed in detail. An optical fiber array of 130 channels with a lens unit is used to spatially resolve the edge plasma into different magnetic field structure components: divertor strike points, divertor legs, X-point of the legs, the stochastic layer, and the last closed flux surface. With a 300 grooves/mm grating, the 2D distributions of several hydrogen and impurity line emissions are simultaneously obtained with absolute intensities. A clear correlation is obtained between the magnetic field structure and the emission intensity. With a 2400 grooves/mm grating with a good spectral resolution (0.03 nm/pixel), the 2D distributions of impurity flow velocity are obtained from the Doppler shift measurement. The wavelength position is accurately calibrated by investigating the wavelength dispersion as well as by correcting a mechanical error of the optical setting in the spectrometer. The uncertainty in the velocity is reduced to less than 10% of a typical impurity velocity ∼104 m/s. A temporal change in the flow directions is observed at different spatial locations in divertor detachment plasma

    Self-evolving photonic crystals for ultrafast photonics

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    高速自己変化可能なフォトニック結晶による高ピーク出力・短パルス光の発生 --超スマート社会を支える高精度光センシングやレーザー微細加工応用に向けて--. 京都大学プレスリリース. 2023-01-27.Ultrafast dynamics in nanophotonic materials is attracting increasing attention from the perspective of exploring new physics in fundamental science and expanding functionalities in various photonic devices. In general, such dynamics is induced by external stimuli such as optical pumping or voltage application, which becomes more difficult as the optical power to be controlled becomes larger owing to the increase in the energy required for the external control. Here, we demonstrate a concept of the self-evolving photonic crystal, where the spatial profile of the photonic band is dynamically changed through carrier-photon interactions only by injecting continuous uniform current. Based on this concept, we experimentally demonstrate short-pulse generation with a high peak power of 80 W and a pulse width of <30 ps in a 1-mm-diameter GaAs-based photonic crystal. Our findings on self-evolving carrier-photon dynamics will greatly expand the potential of nanophotonic materials and will open up various scientific and industrial applications

    Comprehensive Analysis of Risk Factors for Periodontitis Focusing on the Saliva Microbiome and Polymorphism

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    Few studies have exhaustively assessed relationships among polymorphisms, the microbiome, and periodontitis. The objective of the present study was to assess associations simultaneously among polymorphisms, the microbiome, and periodontitis. We used propensity score matching with a 1:1 ratio to select subjects, and then 22 individuals (mean age +/- standard deviation, 60.7 +/- 9.9 years) were analyzed. After saliva collection, V3-4 regions of the 16S rRNA gene were sequenced to investigate microbiome composition, alpha diversity (Shannon index, Simpson index, Chao1, and abundance-based coverage estimator) and beta diversity using principal coordinate analysis (PCoA) based on weighted and unweighted UniFrac distances. A total of 51 single-nucleotide polymorphisms (SNPs) related to periodontitis were identified. The frequencies of SNPs were collected from Genome-Wide Association Study data. The PCoA of unweighted UniFrac distance showed a significant difference between periodontitis and control groups (p 0.05). Two families (Lactobacillaceae and Desulfobulbaceae) and one species (Porphyromonas gingivalis) were observed only in the periodontitis group. No SNPs showed significant expression. These results suggest that periodontitis was related to the presence of P. gingivalis and the families Lactobacillaceae and Desulfobulbaceae but not SNPs
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