Development of an optimal laser for chirp cooling of positronium based on chirped pulse-train generator

We report the development and characterization of a pulsed 243 nm laser that is optimal for the cooling of positronium (Ps). The laser, which is based on the recent chirped pulse-train generator (CPTG) demonstrated by K. Yamada et al. (Phys. Rev. Appl. 16, 014009 (2021)), was designed to output a train of pulses with linewidths of 10 GHz, and with the center frequency of each pulse shifting upward (up-chirped) in time by $4.9\times10^2\,\mathrm{GHz\,\mu s^{-1}}$. These parameters were determined by the mechanism of chirp cooling, which is the best scheme for cooling many Ps atoms to the recoil temperature of laser cooling. To achieve the designed performance, we drove an optical phase modulator in the CPTG with a deep modulation depth based on the operating principle of the cooling laser. Time-resolved spectroscopic measurements confirmed that the developed laser satisfied the chirp rate and linewidth requirements for efficient chirp cooling. Combined with pulse energy of hundreds of microjoules, we believe that the experimental demonstration of Ps laser cooling has become possible using realistic methods for the generation and velocity measurement of Ps.Comment: 11 pages, 11 figure

The OVAL experiment: A new experiment to measure vacuum magnetic birefringence using high repetition pulsed magnets

A new experiment to measure vacuum magnetic birefringence (VMB), the OVAL experiment, is reported. We developed an original pulsed magnet that has a high repetition rate and applies the strongest magnetic field among VMB experiments. The vibration isolation design and feedback system enable the direct combination of the magnet with a Fabry-P\'erot cavity. To ensure the searching potential, a calibration measurement with dilute nitrogen gas and a prototype search for vacuum magnetic birefringence are performed. Based on the results, a strategy to observe vacuum magnetic birefringence is reported.Comment: 9 pages, 11 figure

超低左心機能合併患者の肩腱板断裂手術に対し全身麻酔で管理した1症例

京都府立医科大学附属北部医療センター　麻酔科Department of Anesthesiology,　North Medical center,　Kyoto Prefectural University of Medicine患者は62歳、男性。右肩腱板断裂に対して腱板縫合術が行われた。心筋梗塞の既往があり、術前の経胸壁心臓超音波検査で左室駆出率は18％まで低下していた。麻酔法は腕神経叢ブロック併用の全身麻酔とした。周術期には大量のノルアドレナリンの持続投与を要したが、循環器系合併症は無く順調に退院することができた。Ohmの法則に則った適切な臓器灌流の維持に血管収縮薬による体血管抵抗の増加が有用であったと考える

Solar System Exploration Sciences by EQUULEUS on SLS EM-1 and Science Instruments Development Status

EQUULEUS is a spacecraft to explore the cislunar region including the Earth-Moon Lagrange point L2 (EML2) and will be launched by NASA’s SLS EM-1 rocket. Although the size of EQUULEUS is only 6U, the spacecraft carries three different science instruments. By using these instruments, the spacecraft will demonstrate three missions for solar system exploration science during and after the flight to EML2; imaging of the plasmasphere around the earth, observation of space dust flux in the cislunar region, and observation of lunar impact flashes at the far side of the moon. The developments and verifications of the flight models of these science instruments were completed by the end of 2018, and we started flight model integration and testing. This paper introduces the details of the scientific objectives, design results and development statuses of the instruments. In addition, results of the integration and pre-flight tests are also described

SARS-CoV-2 disrupts respiratory vascular barriers by suppressing Claudin-5 expression

臓器チップ技術を用いて新型コロナウイルスが血管へ侵入するメカニズムを解明 --Claudin-5発現抑制による呼吸器の血管内皮バリア破壊--. 京都大学プレスリリース. 2022-09-22.A study using an organ-on-a-chip reveals a mechanism of SARS-CoV-2 invasion into blood vessels --Disruption of vascular endothelial barrier in respiratory organs by decreasing Claudin-5 expression--. 京都大学プレスリリース. 2022-09-27.In the initial process of coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects respiratory epithelial cells and then transfers to other organs the blood vessels. It is believed that SARS-CoV-2 can pass the vascular wall by altering the endothelial barrier using an unknown mechanism. In this study, we investigated the effect of SARS-CoV-2 on the endothelial barrier using an airway-on-a-chip that mimics respiratory organs and found that SARS-CoV-2 produced from infected epithelial cells disrupts the barrier by decreasing Claudin-5 (CLDN5), a tight junction protein, and disrupting vascular endothelial cadherin–mediated adherens junctions. Consistently, the gene and protein expression levels of CLDN5 in the lungs of a patient with COVID-19 were decreased. CLDN5 overexpression or Fluvastatin treatment rescued the SARS-CoV-2–induced respiratory endothelial barrier disruption. We concluded that the down-regulation of CLDN5 expression is a pivotal mechanism for SARS-CoV-2–induced endothelial barrier disruption in respiratory organs and that inducing CLDN5 expression is a therapeutic strategy against COVID-19

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