2,147 research outputs found

    Non-fragile control for nonlinear networked control systems with long time-delay

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    AbstractThis paper considers the non-fragile control problem for uncertain nonlinear networked control systems (NCSs) with long time-delay and controller gain perturbations. Firstly, the NCS model with random long time-delay is transformed into a discrete-time system model with uncertain parameters. Then, the Lyapunov stability theory and the linear matrix inequality (LMI) approach are applied to design a non-fragile controller, which results in the closed-loop system being asymptotically stable and the system’s cost function value being less than a determinate upper bound. At the same time, the existence condition and the design approach of a non-fragile controller are presented. Finally, simulation examples are employed to verify the validity of the proposed control algorithm

    Optimal Disturbances Rejection Control for Autonomous Underwater Vehicles in Shallow Water Environment

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    To deal with the disturbances of wave and current in the heading control of Autonomous Underwater Vehicles (AUVs), an optimal disturbances rejection control (ODRC) approach for AUVs in shallow water environment is designed to realize this application. Based on the quadratic optimal control theory, the AUVs heading control problem can be expressed as a coupled two-point boundary value (TPBV) problem. Using a recently developed successive approximation approach, the coupled TPBV problem is transformed into solving a decoupled linear state equation sequence and a linear adjoint equation sequence. By iteratively solving the two equation sequences, the approximate ODRC law is obtained. A Luenberger observer is constructed to estimate wave disturbances. Simulation is provided to demonstrate the effectiveness of the presented approach

    NK Cell-Based Immunotherapy for Hematological Malignancies

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    Natural killer (NK) lymphocytes are an integral component of the innate immune system and represent important effector cells in cancer immunotherapy, particularly in the control of hematological malignancies. Refined knowledge of NK cellular and molecular biology has fueled the interest in NK cell-based antitumor therapies, and recent efforts have been made to exploit the high potential of these cells in clinical practice. Infusion of high numbers of mature NK cells through the novel graft manipulation based on the selective depletion of T cells and CD19+ B cells has resulted into an improved outcome in children with acute leukemia given human leucocyte antigen (HLA)-haploidentical hematopoietic transplantation. Likewise, adoptive transfer of purified third-party NK cells showed promising results in patients with myeloid malignancies. Strategies based on the use of cytokines or monoclonal antibodies able to induce and optimize NK cell activation, persistence, and expansion also represent a novel field of investigation with remarkable perspectives of favorably impacting on outcome of patients with hematological neoplasia. In addition, preliminary results suggest that engineering of mature NK cells through chimeric antigen receptor (CAR) constructs deserve further investigation, with the goal of obtaining an "off-the-shelf" NK cell bank that may serve many different recipients for granting an efficient antileukemia activity

    Discrete approximate optimal vibration control for nonlinear vehicle active suspension

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    This paper presents the approximate optimal vibration control methodology for discrete nonlinear vehicle active suspension subject to persistent road disturbances. Based on a dynamic model of nonlinear vehicle active suspension and a linear exogenous system model of the persistent road disturbances, a nonlinear two-point boundary value (TPBV) problem is introduced. By introducing a sensitive parameter, the original TPBV problem is reformed as a series of TPBV problems without nonlinear items. A discrete approximate optimal vibration controller (DAOVC) can be obtained by solving a Riccati equation, Stein equation, and nonlinear compensation item, respectively. An iteration algorithm is designed to realize the computational realizability of DAOVC based on the control performance. It is demonstrated that the control performance of ride comfort, road holding ability, and suspension deflection under the DAOVC are much smaller than the ones under the classical feedforward and feedback optimal vibration controller (FFOVC) and open-loop vehicle suspension system

    Effect of polysaccharide from the root of Bupleurum Chinese DC and Bupleurum scorzonerifolium Willd on hydrogen peroxide-induced myocardial apoptosis

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    Purpose: To investigate the protective effect of polysaccharide (BRP) from the root of Bupleurum Chinese DC. and Bupleurum scorzonerifolium Willd. on cardiomyocyte cells. Methods: Response surface methodology (RSM) based on Box-Behnken Design (BBD) was performed to optimize the extraction conditions for BRP. The effect of BRP on cardiomyocyte cell apoptosis was evaluated in H9c2 cells treated with hydrogen peroxide (H2O2). Cell viability was determined by CCK-8 assay, while oxidative stress levels in H9c2 cells, including lactate dehydrogenase (LDH), superoxide dismutase (SOD), catalase (CAT) and creatine kinase (CK) were determined using commercial kits following the manufacture’s instruction. mRNA expressions (caspase-3, caspase-8, caspase-9 and Fas) were determined by quantitative real time-polymerase chain reaction (RT-qPCR). Results: The obtained optimal extraction conditions for BRP was as follows: extraction time (1.43 h), ratio of water to the raw material (30 mL/g) and extraction times (2 times). BRP (200, 400, 600 and 800 μg/mL) significantly increased the cell viability of H2O2 induced H9c2 cells (p < 0.05, p < 0.01, p < 0.01, p < 0.01, respectively). BRP (200, 400 and 800 μg/mL) significantly decreased LDH and CK levels (p < 0.01, p < 0.01, p < 0.01, respectively). However, BRP increased levels of SOD (200, 400 and 800 μg/mL, p < 0.05) and CAT (400 and 800 μg/mL, p < 0.05) in H9c2 cells. BRP significantly downregulated mRNA expressions of Caspase-3, Caspase-8, Caspase-9 and Fas (200, 400 and 800 μg/mL, p < 0.01) in H9c2 cells induced by H2O2. Conclusion: BRP protects cardiomyocyte against apoptosis via inhibition of oxidative stress and mitochondria-mediated intrinsic apoptosis, and thus, may be potential therapeutic agent for the management of cardiovascular diseases. Keywords: Bupleurum Chinese, Bupleurum scorzonerifolium Willd., Polysaccharide, Cardiomyocyte, Apoptosis, H9c2 cell, Biochemical parameter

    Recurrent acute pancreatitis and massive hemorrhagic ascites secondary to a duodenal duplication in a child: a case report

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    Abstract Introduction Duodenal duplication is a rare congenital malformation and has been reported as a rare cause of recurrent acute pancreatitis. Hemorrhagic ascites has been reported in only one case of duodenal duplication. Case presentation An 11-year-old Chinese girl presented with abdominal pain, hematemesis and dark stools. On admission, an abdominal examination revealed a moderately distended abdomen with diffuse tenderness. Biochemical investigations showed increased serum levels of amylase, lipase, and urine amylase. An abdominal computed tomography scan and magnetic resonance imaging scan revealed an enlarged and heterogeneous pancreas with poorly delineated borders. There was a cystic lesion measuring 25mm × 48mm × 28mm, located between the descending portion of her duodenum and the head of her pancreas. There were massive effusion signals in her abdominal cavity. An exploratory laparotomy was performed. A tubular cyst measuring 32mm × 52mm × 30mm was found in the second part of the duodenum, next to the head of her pancreas. The anterior wall of the duplication cyst was resected and anastomosis of the remaining cyst to the duodenum was performed for drainage. Histopathological examination of the excised cyst wall showed duodenal mucosa, submucosa and muscle coats, indicative of a duodenal duplication. Conclusions It is important to be aware of duodenal duplication when evaluating a patient with recurrent acute pancreatitis accompanied by massive hemorrhagic ascites.Peer Reviewe

    mer-Bis[3,5-difluoro-2-(2-pyrid­yl)phenyl-κ2 C 1,N]{5-(2-pyridyl-κN)-3-[3-(4-vinyl­benz­yloxy)phen­yl]-1,2,4-triazol-1-ido}iridium(III) methanol solvate

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    In the title compound, [Ir(C11H6F2N)2(C22H17N4O)]·CH3OH, the coordination at iridium is essentially octa­hedral, but with distortions associated with the bite angles of the ligands [76.25 (9)–80.71 (12)°] and the differing trans influences of C and N ligands [Ir—N = 2.04 Å (average) trans to N but 2.14 Å trans to C]. All three bidentate ligands have coordinating ring systems that are almost coplanar [inter­planar angles = 1.7 (1)–3.8 (2)°]. The vinyl­benzyl group is disordered over two positions with occupations of 0.653 (4) and 0.347 (4). The methanol solvent mol­ecule is involved in a classical O—H⋯N hydrogen bond to a triazole N atom
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