516 research outputs found

    Sliding mode control with disturbance estimation for underwater robot.

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    This paper proposes a sliding mode control with a disturbance estimation for an underwater robot. The mobility performance of an underwater robot is influenced by modeling error, observation noise, and several disturbances such as ocean current and tidal current. Therefore, a robust control system is needed for precise motion control of an underwater robot. This paper uses a sliding mode control, which is one of the robust control methods. In a sliding mode control, chattering tends to occur, if the switching gain is set to a high value. On the other hand, it is desirable to set the switching gain high from the viewpoint of robustness. Therefore, there is a trade-off between the switching gain and robustness. In the proposed method, the disturbance is estimated in real-time, and this estimated value is added to the control input. Most of the disturbances are compensated by this estimated value, and the sliding mode control is used for the rest of the disturbances. As a result, the robust control system is achieved by using the proposed method, even if the switching gain is set to a low value. The validity of the proposed method was confirmed from the simulation and experimental results

    BALB/c-Fcgr2b−/−Pdcd1−/− mouse expressing anti-urothelial antibody is a novel model of autoimmune cystitis

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    We report the impact of anti-urothelial autoantibody (AUAb) on urinary bladder phenotype in BALB/c mice deficient of the FcγRIIb and PD-1. AUAb was present in serum samples from approximately half of the double-knockout (DKO) mice, as detected by immunofluorescence and immunoblots for urothelial proteins including uroplakin IIIa. The AUAb-positive DKO mice showed degeneration of urothelial plaque and umbrella cells, along with infiltration of inflammatory cells in the suburothelial layer. TNFα and IL-1β were upregulated in the bladder and the urine of AUAb-positive DKO mice. Voiding behavior of mice was analyzed by the Voided Stain on Paper method. 10-week-old and older AUAb-positive DKO mice voided significantly less urine per void than did wild type (WT) mice. Furthermore, administration of the AUAb-containing serum to WT mice significantly reduced their urine volume per void. In summary, this report presents a novel comprehensive mouse model of autoimmune cystitis

    Closure of multiple ventricular septal defects by the felt sandwich technique: Further analysis of 36 patients

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    ObjectivesWe previously described a novel technique for closure of trabecular ventricular septal defects by sandwiching the septum with 2 polyester felt patches without requiring left ventriculotomy. We describe the midterm results of this technique and the postoperative cardiac function.MethodsThis is a retrospective study of 36 consecutive patients. The median age and body weight at the time of repair was 15 months (range: 2-115 months) and 7.8 kg (range: 3.9-51.9 kg), respectively.ResultsSixty-three trabecular ventricular septal defects in 36 patients were closed with the felt sandwich technique. In the early postoperative period, 1 patient died of pulmonary hypertensive crisis. There were 2 late deaths. One patient died of pneumonia 6 months after surgery, and another died suddenly of ventricular arrhythmias 2 years after surgery. Three patients required reoperation (closure of major residual ventricular septal defect, cardiac transplantation for dilated cardiomyopathy, and pacemaker implantation for complete atrioventricular block). Postoperative left ventricular fractional shortening in the group with a body surface area less than 0.4 m2 was significantly lower than that in the group with a body surface area of 0.4 m2 or greater (0.22 ± 0.09 vs 0.31 ± 0.06, P = .0027). Moreover, there was a strong correlation between postoperative left ventricular ejection fraction and total patch area/body surface area ratio (R = −0.74, P = .0004).ConclusionMultiple trabecular ventricular septal defects can be closed with the felt sandwich technique easily and safely. Although this technique can be used in small infants, the use of numerous felt patches disturbs the movement of ventricular septum, which may cause postoperative cardiac dysfunction
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