62 research outputs found
Two Degree of Freedom Adaptive Control for Hysteresis Compensation of Pneumatic Continuum Bending Actuator
Soft robotics, with their inherent flexibility and infinite degrees of
freedom (DoF), offer promising advancements in human-machine interfaces.
Particularly, pneumatic artificial muscles (PAMs) and pneumatic bending
actuators have been fundamental in driving this evolution, capitalizing on
their mimetic nature to natural muscle movements. However, with the versatility
of these actuators comes the intricate challenge of hysteresis - a nonlinear
phenomenon that hampers precise positioning, especially pronounced in pneumatic
actuators due to gas compressibility. In this study, we introduce a novel 2-DoF
adaptive control for precise bending tracking using a pneumatic continuum
actuator. Notably, our control method integrates adaptability into both the
feedback and the feedforward element, enhancing trajectory tracking in the
presence of profound nonlinear effects. Comparative analysis with existing
approaches underscores the superior tracking accuracy of our proposed strategy.
This work discusses a new way of simple yet effective control designs for soft
actuators with hysteresis properties.Comment: Submitted to IEEE Conference on Robotics and Automation (ICRA 2024),
Under Revie
Trajectory Tracking Control of Dual-PAM Soft Actuator with Hysteresis Compensator
Soft robotics is a swiftly evolving field. Pneumatic actuators are suitable
for driving soft robots because of their superior performance. However, their
control is challenging due to the hysteresis characteristics. In response to
this challenge, we propose an adaptive control method to compensate for the
hysteresis of soft actuators. Employing a novel dual pneumatic artificial
muscle (PAM) bending actuator, the innovative control approach abates
hysteresis effects by dynamically modulating gains within a traditional PID
controller corresponding to the predicted variation of the reference
trajectory. Through experimental evaluation, we found that the proposed control
method outperforms its conventional counterparts regarding tracking accuracy
and response speed. Our work reveals a new direction for advancing model-free
control in soft actuators.Comment: This paper has been published in the IEEE Robotics and Automation
Letters ,DOI 10.1109/LRA.2023.3334098, copyright has been transfferd to the
IEEE. Final version is available at IEEE Xplor
Expressions of brain-derived neurotrophic factor(BDNF) in cerebrospinal fluid and plasma of children with meningitis and encephalopathy
Alteration of FHR pattern and cerebral metabolic rate of glucose of the fetus measured by positron emission tomography during progress of acidemia. The significance of overshoot acceleration in FHR
Peer Reviewe
Optimization of prediction methods for risk assessment of pathogenic germline variants in the Japanese population
Predicting pathogenic germline variants (PGVs) in breast cancer patients is important for selecting optimal therapeutics and implementing risk reduction strategies. However, PGV risk factors and the performance of prediction methods in the Japanese population remain unclear. We investigated clinicopathological risk factors using the Tyrer-Cuzick (TC) breast cancer risk evaluation tool to predict BRCA PGVs in unselected Japanese breast cancer patients (n = 1, 995). Eleven breast cancer susceptibility genes were analyzed using target-capture sequencing in a previous study; the PGV prevalence in BRCA1, BRCA2, and PALB2 was 0.75%, 3.1%, and 0.45%, respectively. Significant associations were found between the presence of BRCA PGVs and early disease onset, number of familial cancer cases (up to third-degree relatives), triple-negative breast cancer patients under the age of 60, and ovarian cancer history (all P < .0001). In total, 816 patients (40.9%) satisfied the National Comprehensive Cancer Network (NCCN) guidelines for recommending multigene testing. The sensitivity and specificity of the NCCN criteria for discriminating PGV carriers from noncarriers were 71.3% and 60.7%, respectively. The TC model showed good discrimination for predicting BRCA PGVs (area under the curve, 0.75; 95% confidence interval, 0.69-0.81). Furthermore, use of the TC model with an optimized cutoff of TC score ≥0.16% in addition to the NCCN guidelines improved the predictive efficiency for high-risk groups (sensitivity, 77.2%; specificity, 54.8%; about 11 genes). Given the influence of ethnic differences on prediction, we consider that further studies are warranted to elucidate the role of environmental and genetic factors for realizing precise prediction
A case of acute encephalopathy with biphasic seizures and late reduced diffusion on respiratory syncytial virus infection
JASMINE: Near-infrared astrometry and time-series photometry science
The Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science goals. One is Galactic archaeology with a Galactic Center survey, which aims to reveal the Milky Way’s central core structure and formation history from Gaia-level (∼25 as) astrometry in the near-infrared (NIR) Hw band (1.0–1.6 m). The other is an exoplanet survey, which aims to discover transiting Earth-like exoplanets in the habitable zone from NIR time-series photometry of M dwarfs when the Galactic Center is not accessible. We introduce the mission, review many science objectives, and present the instrument concept. JASMINE will be the first dedicated NIR astrometry space mission and provide precise astrometric information on the stars in the Galactic Center, taking advantage of the significantly lower extinction in the NIR. The precise astrometry is obtained by taking many short-exposure images. Hence, the JASMINE Galactic Center survey data will be valuable for studies of exoplanet transits, asteroseismology, variable stars, and microlensing studies, including discovery of (intermediate-mass) black holes. We highlight a swath of such potential science, and also describe synergies with other missions
Ghrelin and gastric acid secretion
Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-induced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion
Thromboelastography with platelet mapping to guide anesthetic management of emergency cesarean delivery in a patient with thrombasthenia: a case report
Abstract Background Perinatal management of congenital platelet dysfunction represents a challenge. One of the major concerns is whether neuraxial anesthesia can be applicable for cesarean delivery. We present a patient with thrombasthenia who underwent emergency cesarean delivery. Case presentation A 34-year-old primipara was diagnosed with autosomal dominant thrombasthenia, which was not classified as any known type. A thorough examination revealed that adenosine diphosphate aggregation and collagen aggregation were suppressed. Platelet mapping of viscoelastic testing was used to observe the trajectory of platelet function during pregnancy, which was found to be normal to hypercoagulable until 38 weeks of gestation. On the basis of the results of testing and physiological status, we commenced spinal anesthesia and avoided prophylactic platelet transfusion. Conclusion The platelet mapping of viscoelastic testing was rapid and simple, allowing repeated examinations. We could choose the appropriate anesthesia method and determine the necessity of blood transfusion for a pregnant patient with thrombasthenia
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