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To investigate whether dantrolene (DAN), cardiac ryanodine receptor (RyR2) stabilizer, improves impaired diastolic function in an early pressure-overloaded hypertrophied heart, pressure-overload hypertrophy was induced by transverse aortic constriction (TAC) in mice. Wild-type (WT) mice were divided into four groups: sham-operated mice (Sham), sham-operated mice treated with DAN (DAN+Sham), TAC mice (TAC), and TAC mice treated with DAN (DAN+TAC). The mice were then followed up for 2 weeks. Left ventricular (LV) hypertrophy was induced in TAC, but not DAN+TAC mice, 2 weeks after TAC. There were no differences in LV fractional shortening among the four groups. Catheter tip micromanometer showed that the time constant of LV pressure decay, an index of diastolic function, was significantly prolonged in TAC but not in DAN+TAC mice. Diastolic function was significantly impaired in TAC, but not in DAN+TAC mice as determined by cell shortening and Ca^{2+} transients. An increase in diastolic Ca^{2+} leakage and a decrease in calmodulin (CaM) binding affinity to RyR2 were observed in TAC mice, while diastolic Ca^{2+} leakage improved in DAN+TAC mice. Thus, DAN prevented the progression of hypertrophy and improved the impairment of LV relaxation by inhibiting diastolic Ca^{2+} leakage through RyR2 and the dissociation of CaM from RyR2.

One way of ensuring operator's safety during human-robot collaboration is through Speed and Separation Monitoring (SSM), as defined in ISO standard ISO/TS 15066. In general, it is impossible to avoid all human-robot collisions: consider for instance the case when the robot does not move at all, a human operator can still collide with it by hitting it of her own voluntary motion. In the SSM framework, it is possible however to minimize harm by requiring this: \emph{if} a collision ever occurs, then the robot must be in a \emph{stationary state} (all links have zero velocity) at the time instant of the collision. In this paper, we propose a time-optimal control policy based on Time-Optimal Path Parameterization (TOPP) to guarantee such a behavior. Specifically, we show that: for any robot motion that is strictly faster than the motion recommended by our policy, there exists a human motion that results in a collision with the robot in a non-stationary state. Correlatively, we show, in simulation, that our policy is strictly less conservative than state-of-the-art safe robot control methods. Additionally, we propose a parallelization method to reduce the computation time of our pre-computation phase (down to 0.5 sec, practically), which enables the whole pipeline (including the pre-computation) to be executed at runtime, nearly in real-time. Finally, we demonstrate the application of our method in a scenario: time-optimal, safe control of a 6-dof industrial robot., Comment: 8 pages, submitted to IROS 2023

In order to safely and efficiently collaborate with humans, industrial robots need the ability to alter their motions quickly to react to sudden changes in the environment, such as an obstacle appearing across a planned trajectory. In Realtime Motion Planning, obstacles are detected in real time through a vision system, and new trajectories are planned with respect to the current positions of the obstacles, and immediately executed on the robot. Existing realtime motion planners, however, lack the smoothing post-processing step -- which are crucial in sampling-based motion planning -- resulting in the planned trajectories being jerky, and therefore inefficient and less human-friendly. Here we propose a Realtime Trajectory Smoother based on the shortcutting technique to address this issue. Leveraging fast clearance inference by a novel neural network, the proposed method is able to consistently smooth the trajectories of a 6-DOF industrial robot arm within 200 ms on a commercial GPU. We integrate the proposed smoother into a full Vision--Motion Planning--Execution loop and demonstrate a realtime, smooth, performance of an industrial robot subject to dynamic obstacles., Accepted to ICRA2022

The Nakayama Shell Midden site dates from the Final Jomon to the Middle Yayoi period, and is located in the vicinity of Hiroshima City, Hiroshima prefecture. Artifacts excavated from this site are known as “Nakayama-style pottery”, and are representative of this time period. Here, we report on the Nakayama I type pottery of the first half of the Early Yayoi period, and present a plan for subdividing it into classes. This classification scheme makes it possible to understand the nature of the transition from the Nakayama B type pottery of the Final Jomon, to the Nakayama II type pottery of the latter half of the Early Yayoi period, suggesting a temporal and successive continuity.

いわゆる「鉄芯」入り青銅剣（バイメタル青銅剣）とされてきた広島大学考古学研究室所蔵資料についての再調査を行う。バイメタル青銅剣は、紀元前800～1200ごろ年にカスピ海南部の山岳地帯において出現する金属器で、鉄利用の初期の様相を明らかにするうえで重要である。西アジア北部地域における鉄製利器の祖型として、鉄製棒状部品を内蔵する青銅剣（「鉄芯」入り青銅剣）の存在が指摘され、編年・機能研究が行われてきた。しかし、当該資料はおそらく現代において改変された青銅柄鉄剣であったことが判明した。他機関所蔵品の知見も加味すると、研究対象の多くに同様の可能性があり、「鉄芯入り」青銅剣を前提に導かれたこれまでの知見や議論は根本的な見直しを迫られることになる。紀元前2000年紀の終わりにカスピ海周辺に出現する「鉄芯入り」青銅剣が実は青銅柄鉄剣であったわけであり、それ以前に鉄製利器の導入期といった、より原初的な初期鉄器の実態がある可能性が高くなる。今回の再調査はそうした研究の脆弱性を露呈し、西アジアにおける初期鉄器時代の議論を転換する結果となった。

We present an approach for deposition of highly conductive nominally undoped ZnO films that are suitable for the n-type window of low band gap solar cells. We demonstrate that low-voltage radio frequency (RF) biasing of growing ZnO films during their deposition by non-reactive sputtering makes them as conductive as when doped by aluminium (ρ≤1·10−3Ω cm). The films prepared with additional RF biasing possess lower free-carrier concentration and higher free-carrier mobility than Al-doped ZnO (AZO) films of the same resistivity, which results in a substantially higher transparency in the near infrared region (NIR). Furthermore, these films exhibit good ambient stability and lower high-temperature stability than the AZO films of the same thickness. We also present the characteristics of Cu(InGa)Se2, CuInSe2 and Cu2ZnSnSe4-based solar cells prepared with the transparent window bilayer formed of the isolating and conductive ZnO films and compare them to their counterparts with a standard ZnO/AZO bilayer. We show that the solar cells with nominally undoped ZnO as their transparent conductive oxide layer exhibit an improved quantum efficiency for λ > 900 nm, which leads to a higher short circuit current density JSC. This aspect is specifically beneficial in preparation of the Cu2ZnSnSe4 solar cells with band gap down to 0.85 eV; our champion device reached a JSC of nearly 39 mAcm−2, an open circuit voltage of 378 mV, and a power conversion efficiency of 8.4 %.

その他のタイトル:広島大学大学院文学研究科 帝釈峡遺跡群発掘調査室年報ⅩⅩⅧ