Multiple Environment Integral Reinforcement Learning-Based Fault-Tolerant Control for Affine Nonlinear Systems.

This paper studies the fault-tolerant control (FTC) problem for unknown affine nonlinear systems with actuators faults. The considered types of faults are stuck (lock-in-place), loss-in-effectiveness (LIE), and bias, under which a part of the actuators is disabled. The objective is to find the remaining (not fully LIE) actuators, and manipulate them to obtain the best achievable performance in real time. First, considering that the best achievable performance is determined by the remaining actuators, a set of basic policies is predesigned with multiple levels of performances for different groups of activated actuators. Second, an identifier is designed based on history data to find the remaining actuators and, thus, the suitable predesigned basic policy. Third, to further accommodate the partial LIEs and biases, a compensator works together with the selected basic policy, to build the predesigned performance. In addressing the FTC problem, several techniques are developed: adjustable mechanisms are novelly integrated to deal with the state-dependent nonlinearities in neural network (NN) approximation, disturbances, and mismatch errors; history data are newly applied to estimate the faulty parameters; and a compensator is specially designed to deal with LIEs and biases in different input channels. Also in theory, the convergences of algorithms and the stability of closed-loop systems are proved, by formally giving the invariant sets of the initial state and the NN weights. Unlike the existing FTC methods dealing with LIE and bias based on model information to optimize the tracking error, this result can handle stuck faults without knowing system dynamics and satisfy different levels of performances described by Hamilton-Jacobi-Bellman equations. Finally, a simulation example of quadrotor unmanned aerial vehicle is given to verify the effectiveness of the proposed FTC scheme.

Cooperative Fault Diagnosis for Uncertain Nonlinear Multiagent Systems Based on Adaptive Distributed Fuzzy Estimators.

This paper presents a cooperative fault diagnosis scheme for a class of uncertain nonlinear multiagent systems component and sensor faults in individual agents. Since the faulty system affects the healthy systems through interconnections, for each agent an estimator is designed to collect neighboring output estimations errors to consider its faulty effects on others, when computing its estimations for local state and faulty parameters. A new structure of distributed estimators is proposed by filtering regressor signals and sharing them among agents. Then, the sharings of signals are planned by properly constructing auxiliary graphs for undirected and directed networks. Two conditions are given to preselect estimators parameters for the convergences of the estimation errors. Unlike the existing results dealing with one common parameter with full state measurement and only for undirected graphs, this paper presents an output measurement-based approach for multiple parameters in undirected/directed networks. It shows that for the faults not providing persistent excitation in a signal agent, it is possible to estimate the faults exactly if the they excite all agents persistently. A simulation example of a group of single-link flexible-joint robots is given to verify the effectiveness of the proposed method.

Clinicopathological characteristics of angiofibroma of soft tissue: report of three cases.

Angiofibroma of soft tissue (AFST) is a recently-reported, rare, fibrovascular soft tissue neoplasm that commonly develops in the lower extremities of middle-aged women. Here, we report three cases located in the right temporal lobe of a woman, the left popliteal fossa of a female, and the right lower limb of a male patient, respectively, the former of which is first reported in the light of a literature review owing to its anatomical location. Histological and immunohistochemical features were consistent with the diagnosis of AFST. The two female patients have been individually followed up for 20 and 16 months after surgical resection without any local recurrences or any metastases. Meanwhile, we reviewed the clinicopathological characteristics of 81 AFST to further characterize this tumor. In addition, AFST is a benign tumor that should be considered in the differential diagnosis of a solitary fibrous tumor, a low-grade fibromyxoid sarcoma, and low-grade myxofibrosarcoma, to avoid being misdiagnosed as malignant.

Association between sociodemographic, psychosocial, lifestyle factors, and self-reported health among migrant laborers in China.

BACKGROUND: There were 245 million migrants in China in 2013, the majority of whom migrated from rural to urban areas. Thus, the purpose of this study was to investigate the association between sociodemographic, psychosocial, and lifestyle factors, and self-reported health (SRH) in Chinese migrant laborers. METHODS: This study was conducted based on data from the China Labor-force Dynamics Survey 2012. SRH was measured in a single item, although there were other risk factors from three different groups: sociodemographic, psychosocial, and lifestyle factors. The associations between these risk factors and SRH were tested using multilevel logistic regression analyses including interaction tests. RESULTS: All three groups of factors were explored simultaneously. These factors included age, working hours, marital status, illness, and hospitalization, which were associated with poor SRH, as well as earnings, number of friends, relations with neighbors, trust level, education, and alcohol consumption, which were associated with good SRH. However, there was minimal association found between the two factors of medical insurance and nationality, and SRH. CONCLUSION: Our investigation indicated that there are many factors associated with SRH. In particular, this study undertook a comprehensive investigation of the associations between sociodemographic, psychosocial, lifestyle factors, and SRH in China, the results of which could better inform medical researchers and governments from a Chinese perspective.

[The functional mechanism of CIK cells on ovarian carcinoma cell lines SKOV3/CDDP].

AIM: To investigate the functional mechanism of CIK cells or ovarian carcinoma cell lines SKOV3/CDDP. METHODS: The changes of ultramicrostructure, cell cycle, apoptosis, expression of multidrug resistance-associated protein (MDR1, Topo-IIbeta) and other molecules (hB7-1, hB7-2, MHCIb, HLA-DR) of SKOV3/CDDP cells treated with or without CIK cells were detected by electron microscope, MTT and FCM. The changes of cytokine (IL-2, TNF-alpha, IFN-gamma, GM-CSF) in sera of SCID mice bearing SKOV3/CDDP cells were detected by radioimmunit and ELISA. RESULTS: CIK cells could induce apoptosis of the SKOV3/CDDP cells by electronmicroscopic observations. The apoptosis rate in CIK group was 9.07%, and its cell cycle was arrested at S and G2/M phase (P<0.05). Compared with NS Group, the co-expression of MDR-1 and Topo-IIbeta were decreased significantly in the CIK treated group(P<0.05), and the expression of MHCIb, HLA-DR, hB7-1 and hB7-2 antigen were increased significantly (P<0.01). Compared with NS Group, the contents of IL-2, TNF-alpha, INF-gamma, GM-CSF were increased significantly (P<0.01) in SCID mice of CIK group. CONCLUSION: CIK cells have several important biological effects on the ovarian carcinoma cell line SKOV3/CDDP, which may lay the foundation for further research on anti-tumor therapy.

Strong cellular and humoral immune responses induced by transcutaneous immunization with HBsAg DNA-cationic deformable liposome complex.

Transcutaneous immunization presents a major challenge on account of poor permeability of antigens through the skin barrier. To overcome this limitation, the deformable liposome could be a better method for transcutaneous delivery of these antigens. In this study, hepatitis B surface antigen (HBsAg) plasmid DNA-cationic complex deformable liposome was utilized as a mode for enhanced immunity against the antigen. Deformable liposome was prepared by conventional rotary evaporation method and characterized for various parameters such as vesicles shape and surface morphology, size and size distribution, entrapment efficiency, elasticity and stability. The immune stimulating activity was studied by measuring serum anti-HBsAg titre and cytokines level (interleukin-4 and interferon-gamma) following topical application of liposome in BALB/c mice and results were compared with deformable liposome encapsulated DNA applied topically as well as naked DNA and pure recombinant HBsAg, administered intramuscularly. It was observed that deformable liposome elicited a comparable serum antibody titre and endogenous cytokines levels compared to other vaccinations. The study signifies the potential of deformable liposome as DNA vaccine carriers for effective transcutaneous immunization.

Expression of vascular endothelial growth factor-C and the relationship between lymphangiogenesis and lymphatic metastasis in colorectal cancer.

AIM: To investigate the expression of vascular endothelial growth factor-C (VEGF-C) and the relationship between VEGF-C and lymphangiogenesis, lymph node metastasis in colorectal cancer. METHODS: Fifty six cases of colorectal cancer were selected randomly. Expression of VEGF-C was detected by immunohistochemistry, and lymphatic vessels were stained by enzyme histochemical method. RESULTS: VEGF-C expression was found in 66.7% (37/56) patients. In VEGF-C positive and negative patients, the lymphatic vessel density was 25.16+/-7.52 and 17.14+/-7.22, respectively (P<0.05). The rate of lymph node metastasis in VEGF-C positive patients (81.1%) was significantly higher than that in the negative group (42.1%). CONCLUSION: VEGF-C expression may induce lymphangiogenesis in colorectal cancer, as a result, tumor cells can entry the lymphatic vessels easily. VEGF-C may serve as a useful prognotic factor in colorectal carcinoma.