Time-Optimal Path Tracking with ISO Safety Guarantees

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 202

Real-time Batched Distance Computation for Time-Optimal Safe Path Tracking

In human-robot collaboration, there has been a trade-off relationship between the speed of collaborative robots and the safety of human workers. In our previous paper, we introduced a time-optimal path tracking algorithm designed to maximize speed while ensuring safety for human workers. This algorithm runs in real-time and provides the safe and fastest control input for every cycle with respect to ISO standards. However, true optimality has not been achieved due to inaccurate distance computation resulting from conservative model simplification. To attain true optimality, we require a method that can compute distances 1. at many robot configurations to examine along a trajectory 2. in real-time for online robot control 3. as precisely as possible for optimal control. In this paper, we propose a batched, fast and precise distance checking method based on precomputed link-local SDFs. Our method can check distances for 500 waypoints along a trajectory within less than 1 millisecond using a GPU at runtime, making it suited for time-critical robotic control. Additionally, a neural approximation has been proposed to accelerate preprocessing by a factor of 2. Finally, we experimentally demonstrate that our method can navigate a 6-DoF robot earlier than a geometric-primitives-based distance checker in a dynamic and collaborative environment

The relation between visceral adipose tissue accumulation and biochemical tests in university students.

We evaluated the visceral adipose tissue accumulation in university students in Okayama prefecture, Japan. Fifty-eight Japanese university students (10 men and 48 women, age 18.4 +/- 0.6 years)were enrolled in this study. Fat distribution was evaluated by visceral fat (V) and subcutaneous fat (S) areas measured with computed tomography (CT) scanning at umbilical levels. Anthropometric parameters,i.e., height, weight, waist circumference, hip circumference, and body fat percentage; blood examination; and blood pressure (BP) were also measured. In 58 subjects, the V area was 23.4 +/- 21.0 cm(2) and the S area was 122.5 +/- 57.9 cm(2). V areas were significantly correlated with hepatic enzymes, uric acid, triglyceride, and BP in men, while they were weakly correlated with hepatic enzymes, triglyceride, and high density lipoprotein (HDL) cholesterol in women. Correlation coefficients between V areas and clinical parameters were comparatively higher than those between other body composition parameters,i.e., S areas, weight, body mass index (BMI), body fat percentage, and clinical parameters. The present study suggests that visceral adipose tissue accumulation is important for hepatic enzymes, uric acid, triglyceride, and BP in university students.</p

Retrograde axonal transport of Poliovirus and EV71 in motor neurons

Poliovirus (PV) can spread through neural pathway to the central nervous system and replicates in motor neurons, which leads to poliomyelitis. Enterovirus 71 (EV71), which is closely related to PV, is one of the causative agents of hand-foot-and-mouth disease and can cause severe neurological diseases similar to poliomyelitis. Since PV is similar to EV71 in its motor neurotoxicity, we tried to understand if the results obtained with PV are of general applicability to EV71 and other viruses with similar characteristics. Using microfluidic devices, we demonstrated that both PV capsid and the PV genome undergo axonal retrograde transport with human PV receptor (hPVR), and the transported virus replicated in the soma of hPVR-expressing motor neurons. Similar to PV in hPVR-transgenic (Tg) mice, neural pathway ensuring spreading of EV71 has been shown in adult human scavenger receptor class B, member 2 (hSCARB2)-Tg mice. We have validated this finding in microfluidic devices by showing that EV71 is retrogradely transported together with hSCARB2 to the cell body where it replicates in an hSCARB2-dependent manner

The metastasis suppressor KISS1 lacks antimetastatic activity in the C8161.9 xenograft model of melanoma.

The objective of this study was to use the established xenograft model of human melanoma (C8161.9) to test a pharmacological approach to the effect of the metastasis suppressor KISS1. A KISS1 analog was used to inhibit the metastatic development of C8161.9 cells in nude mice. Further experiments were performed to test the validity of the C8161.9 model and test the connection between KISS1 expression and loss of metastatic potential. New clones of C8161.9 cells were obtained, with or without KISS1 expression, and were tested for metastasis formation. The absence of benefit in survival with the KISS1 analog compared with PBS prompted us to revisit the C8161.9 model. We found that the cells expressing KISS1, used in the previous study and obtained by transfection and single-cell cloning, were defective for both formation of orthotopic tumors and metastases. In mixing experiments, these cells could not suppress orthotopic tumor growth of KISS1-negative C8161.9 cells, suggesting that the suppression of metastasis by C8161.9-KISS1 cells may be intrinsic to the selected clone rather than related to KISS1 expression. Isolation of clones from parental C8161.9 cells in soft agar yielded cell populations that phenotypically and genotypically mimicked the KISS1-positive clone. In addition, new clones expressing KISS1 did not show any decrease in metastatic growth. These data demonstrate the heterogeneity of cell types in the C8161.9 cell line and the high risk of artifact linked to single-cell selection. A different xenograft model will be necessary to evaluate the use of KISS1 analogs as antimetastatic therapy

A METHOD FOR ESTIMATING ELBOW VARUS TORQUE USING ONLY A BASEBALL WITH AN EMBEDDED SENSOR

Currently, to measure the elbow varus torque during baseball pitching, it is necessary to attach markers and sensors to the body. The purpose of this study is to develop the method for estimating elbow varus torque by only a baseball with an embedded sensor, and examine the accuracy. Eight baseball pitchers threw a four-seam fastball with maximum effort. The varus torque was estimated using one-link-segment model by an accelerometer and gyro sensor placed in the baseball. The Intraclass Correlation Coefficients between the maximum values of the varus torque calculated by the proposed method and the values calculated by the motion capture system was high (ICC(3,1) = 0.73).This result indicates that proof of concept by one-link model is success and warrants future research to potentially develop a system with greater accuracy

Analysis of Immunity against Measles, Mumps, Rubella, and Varicella Zoster in Adult Recipients of Allogeneic Hematopoietic Stem Cell Transplantation: A Single-Center Experience

Vaccine-preventable disease (VPD) infections are more severe in immunocompromised hosts. Vaccination against measles, mumps, rubella, and varicella zoster (VZV) (MMRV) is therefore recommended for hematopoietic stem cell transplantation (HCT) recipients. However, studies on adult HCT recipients with VPD infections are limited. At our institution, we have systematically conducted serological MMRV tests as a part of check-up examinations during long-term follow-up (LTFU) after HCT since 2015. This retrospective study aimed to evaluate changes in the serostatus between before and 2 years after allogeneic HCT. Among 161 patients, the pre-transplant seropositivity was 82.7% for measles, 86.8% for mumps, 84.2% for rubella, and 94.3% for VZV. Among 56 patients who underwent LTFU including serological MMRV tests at 2 years after HCT, the percentages maintaining seroprotective antibody levels for measles, mumps, rubella and VZV were 71.5% (40/56), 51.8% (29/56), 48.2% (27/56), and 60.7% (34/56), respectively. Vaccination was recommended for 22 patients, and 12 were vaccinated. Among the 12 vaccinated patients, rates of seroconversion were examined in 2-6 patients for each of the four viruses. They were 100% (3/3) for measles, 33.3% (1/3) for mumps, 50% (3/6) for rubella, and 0% (0/2) for VZV. Further studies are warranted to clarify the effect of vaccination in adult HCT recipients

The Level and Stability of Residual Catalase in Cultured Acatalasemic Skin Fibroblasts

In an attempt to determine the level and heat stability of residual catalase in somatic cells of acatalasemic Japanese, skin fibroblasts from an acatalasemic subject were cultured, and the catalase activity of the cultured fibroblasts was compared with that of cultured normal fibroblasts. Catalase activity was determined using an oxygen electrode. The residual catalase activity in cultured acatalasemic fibroblasts was 10% of the normal. The heat stability at 55 degrees C of residual catalase in the acatalasemic fibroblasts was similar to that of normal fibroblasts

広島大学考古学研究室所蔵の西アジア青銅柄鉄剣をめぐって

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

Examples of Artifacts from the Nakayama Shell Midden: Nakayama I type Rice Kettle Ceramics <Research and Studies at the Department of Archaeology: New Research Material>

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