Angle Control of a Pneumatically Driven Musculoskeletal Model Based on Coordination of Agonist-Antagonist Muscle

In recent years, researchers have been actively pursuing research into developing robots that can be useful in many fields of industry (e.g., service, medical, and aging care). Such robots must be safe and flexible so that they can coexist with people. Pneumatic actuators are useful for achieving this goal because they are lightweight units with natural compliance. Our research focuses on joint angle control for a pneumatically driven musculoskeletal model. In such a model, we use a one-degree-of-freedom joint model and a five-fingered robot hand as test beds. These models are driven by low pressure-driven pneumatic actuators, and mimic the mechanism of the human hand and musculoskeletal structure, which has an antagonistic muscle pair for each joint. We demonstrated a biologically inspired control method using the parameters antagonistic muscle ratio and antagonistic muscle activity. The concept of the method is based on coordination of an antagonistic muscle pair using these parameters. We have investigated the validity of the proposed method both theoretically and experimentally, developed a feedback control system, and conducted joint angle control by implementing the test beds.ArticleJournal of Mechanics Engineering and Automation. 2(12):709-719 (2012)journal articl

Robot-assisted endoscopic surgery experience

In Japan,１２ new operative robot-assisted endoscopic surgery methods were officially approved by the ２０１８ revision of the medical payment system, and robot-assisted endoscopic surgery is using in each field. We have used the pneumatically driven endoscope manipulator robot（EMAROⓇ）in three video-assisted thoracoscopic surgery（VATS）lobectomy cases : right upper lobe lung cancer in a ５３-year-old male, right lower lobe lung cancer in a ７０-year-old male, and right lower lobe lung cancer in an ８１-year-old female. The average operative time was ２０９ min. The average bleeding volume was ４６．７ml. The grades ware nearly equal to those obtained in a standard VATS lobectomy. The head sensor that monitors the movement of the operator is connected to the endoscope holder. The operator can thus move the endoscope smoothly from the operator’s point of view, and endoscope-user skill is not needed. A VATS lobectomy can be performed by only two operators （no scope user is needed）, and this is a major advantage of the new manipulator robot. We expect to see further advances in the use of robot assistance in surgeries

Effects of verapamil and lidocaine on two components of the re-entry circuit of verapamil-sensitive idiopathic left ventricular tachycardia

AbstractOBJECTIVESWe characterized pharmacologically the slow conduction zone of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) with regard to the late diastolic potential (LDP).BACKGROUNDWe showed that the slow conduction zone of ILVT could be divided into two components by LDP; that is, the distal component with a tachycardia-dependent conduction delay property and the proximal one without it.METHODSElectrophysiologic studies were performed in eight consecutive patients. The LDP was recorded during left ventricular (LV) mapping during ILVT. Entrainment was performed from the right ventricular outflow tract while recording LDP. The effects of lidocaine (1 mg/kg body weight) and verapamil (0.5 or 1.0 mg) were examined during entrainment.RESULTSThe LDPs preceding the Purkinje potential (PP) were serially recorded from the upper third to the middle of the LV septum along the narrow longitudinal line. The ventricular tachycardia (VT) cycle length increased after lidocaine (p < 0.05), and further after verapamil (p < 0.05). The increments in the VT cycle length after administration of the drugs strongly correlated with those in LDP-PP (r > 0.9 for both drugs). The interval from the ventricular potential to LDP was unchanged after administration of the drugs. In one patient, verapamil terminated VT by local conduction block between LDP and PP. The LDP-PP measured during entrainment increased after lidocaine, and further after verapamil, whereas the interval from the stimulus to LDP remained unchanged.CONCLUSIONSThe component distal to LDP is mainly calcium channel-dependent and partly depressed sodium channel-dependent. The proximal component is considered to be sodium channel-dependent (normal)

Comprehensive Investigations of Multiple Factors That Are Related to Refractory Outcome in Urosepsis Patients

Background: Urosepsis is an acute life-threating disease, and some cases show refractory outcome to therapy. In an aging society of developed countries, characteristics of urosepsis are becoming complicated. We performed a comprehensive investigation regarding the clinical and social aspects that are related to refractory outcomes in urosepsis patients. Methods: The patient cohort consisted of 66 patients with urosepsis. Multiple factors from clinical and social aspects were reviewed retrospectively. Two categories of refractory outcomes were defined. One was afebrile resistance (AR); fever continued more than 7 days from the initiation of therapy. Another was discharge resistance (DR); hospitalization continued for more than 30 days. Logistic regression analyses were performed to identify significant factors that are related to the AR or DR. Results: Univariate analysis demonstrated that high score of Eastern Cooperative Oncology Group Performance Status (ECOG PS) (? 2) and Age-adjusted Charlson comorbidity index (CCI) (? 4), high serum C-reactive protein (CRP) level (? 14.9 mg/dL), and low serum albumin level (? 2.26 g/dL) were significantly related to AR. Univariate analysis results also revealed that high score of ECOG PS (? 2), high serum creatinine level (? 1.54 mg/dL) and vasopressor administration were significantly related to DR. Multivariate analyses demonstrated that low serum albumin level (? 2.26g/dL) was the only significant factor that was related to AR. In contrast, high score of ECOG PS (? 2) and high serum creatinine level (? 1.54 mg/dL) were significant factors that were related to DR. Conclusion: It is suggested that evaluating serum albumin levels is essential for the therapeutic first step because hypoalbuminemia was the significant factor that was related to obstruction to antipyresis. It is also suggested that the deterioration of patients’ activities of daily living and renal dysfunction might be the refractory factors for discharge from the hospital, which was the ultimate therapeutic goal

超高速鉄道トンネルの微気圧波の評価およびその低減対策の提案

学位の種別: 論文博士審査委員会委員 : （主査）東京大学教授 石原 孟, 東京大学教授 前川 宏一, 東京大学准教授 長山 智則, 成蹊大学教授 小川 隆申, 横浜国立大学上級特別教授 藤野 陽三University of Tokyo(東京大学