Adaptive fault-tolerant attitude tracking control for hypersonic vehicle with unknown inertial matrix and states constraints

This paper proposes an adaptive fault-tolerant control (FTC) method for hypersonic vehicle (HSV) with unexpected centroid shift, actuator fault, time-varying full state constraints, and input saturation. The occurrence of unexpected centroid shift has three main effects on the HSV system, which are system uncertainties, eccentric moments, and variation of input matrix. In order to ensure the time-varying state constraints, a novel attitude state constraint control strategy, to keep the safe flight of HSV, is technically proposed by a time-varying state constraint function (TVSCF). A unified controller is designed to handle the time-varying state constraints according to the proposed TVSCF. Then, the constrained HSV system can be transformed into a novel free-constrained system based on the TVSCF. For the variation of system input matrix, input saturation and actuator fault, a special Nussbaum-type function is designed to compensate for those time-varying nonlinear terms. Additionally, the auxiliary systems is designed to compensate the constraint of system control inputs. Then, it is proved that the proposed control scheme can guarantee the boundedness of all closed-loop signals based on the Lyapunov stability theory. At last, the simulation results are provided to demonstrate the effectiveness of the proposed fault-tolerant control scheme.</p

Distributed secure surrounding control for multiple USVs against deception attacks: a Stackelberg game approach with reinforcement learning

This article investigates the Stackelberg game-based distributed secure surrounding control (SSC) problem for multiple unmanned surface vehicles (USVs) with unknown dynamics under deception attacks (DAs). The proposed scheme is rooted in the Stackelberg game with reinforcement learning (RL), in which the attacker and controller respectively play the roles of the follower and leader, making sequential decisions of the DA and the SSC. Specifically, a distributed target estimator is established to access the target position. By utilizing this estimated position to formulate an intermediate control law, the target surrounding scenario is effectively transformed into the Stackelberg game-solving problem. The RL approach with a neural networks-based actor-critic learning structure is deployed to directly derive the distributed optimal SSC and DA policies from the Bellman error, whilst learning the unknown dynamics of USVs. Moreover, a value function decomposition technique is applied optimally for using the designed control parameters, thereby accelerating the acquisition of optimal policies. A rigorous theoretical analysis is employed to ensure the closed-loop stability of multiple USVs. Simulations are provided to validate the effectiveness of the proposed distributed SSC scheme for multiple USVs

Application of CRISPR-Cas9 gene editing technology in basic research, diagnosis and treatment of colon cancer

Colon cancer is the fourth leading cause of cancer death worldwide, and its progression is accompanied by a complex array of genetic variations. CRISPR/Cas9 can identify new drug-resistant or sensitive mutations in colon cancer, and can use gene editing technology to develop new therapeutic targets and provide personalized treatments, thereby significantly improving the treatment of colon cancer patients. CRISPR/Cas9 systems are driving advances in biotechnology. RNA-directed Cas enzymes have accelerated the pace of basic research and led to clinical breakthroughs. This article reviews the rapid development of CRISPR/Cas in colon cancer, from gene editing to transcription regulation, gene knockout, genome-wide CRISPR tools, therapeutic targets, stem cell genomics, immunotherapy, metabolism-related genes and inflammatory bowel disease. In addition, the limitations and future development of CRISPR/Cas9 in colon cancer studies are reviewed. In conclusion, this article reviews the application of CRISPR-Cas9 gene editing technology in basic research, diagnosis and treatment of colon cancer

Sexual Knowledge, attitudes and behaviors among unmarried migrant female workers in China: a comparative analysis

<p>Abstract</p> <p>Background</p> <p>In recent years, many studies have focused on adolescent's sex-related issues in China. However, there have been few studies of unmarried migrant females' sexual knowledge, attitudes and behaviors, which is important for sexual health education and promotion.</p> <p>Methods</p> <p>A sample of 5156 unmarried migrant female workers was selected from three manufacturing factories, two located in Shenzhen and one in Guangzhou, China. Demographic data, sexual knowledge, attitudes and behaviors were assessed by self-administered questionnaires. Multivariate logistic regression analysis was conducted to examine the factors associated with premarital sexual intercourse.</p> <p>Results</p> <p>The average age of the unmarried female workers included in the sample was 20.2 years, and majority of them showed a low level of sex-related knowledge. Females from the west of China demonstrated a significant lower level of sex-related knowledge than those from the eastern or central provinces (<it>p </it>< 0.05). Approximately 13% of participants held a favorable attitude towards premarital sexual intercourse, and youths from the east/central were more likely to have favorable attitudes compared with those from the west (<it>p </it>< 0.05). About 17.0% of the unmarried female workers reported having engaged in premarital sexual intercourse, and females from the east/central were more likely to have experienced premarital sexual intercourse than those from the west (<it>p </it>< 0.05). Multivariate analysis revealed that age, education, current residential type, dating, sexual knowledge, attitudes, and pattern of communication were significantly associated with premarital sexual intercourse.</p> <p>Conclusion</p> <p>The unmarried migrant female workers lack sexual knowledge and a substantial proportion of them are engaged in premarital sexual behaviors. Interventions aimed at improving their sexual knowledge and related skills are needed.</p

Adaptive Fault-Tolerant Control of Hypersonic Vehicles with Unknown Model Inertia Matrix and System Induced by Centroid Shift

In this paper, the fault-tolerant control problem of hypersonic vehicle (HSV) in the presence of unexpected centroid migration, actuator failure and external interference is studied in depth. First, the proposed dynamics for HSV with the aforementioned unexpected factors are modeled to demonstrate the peculiar nature of the subject under study. The adverse effects of accidental centroid migration are mainly reflected in the following aspects: (1) the change of inertia matrix of the system, (2) the uncertainty of the system and (3) the eccentric moment, which are coupled and unknown. Subsequently, to account for the effect of unexpected centroid shifts, a sliding-mode observer and an adaptive estimator are designed to obtain unknowns useful for subsequent FTC controller designs. Later, we derived an innovative adaptive FTC scheme by employing the observer in conjunction with a specific adaptive controller consisting of a sixth-order dynamic compensator, which can guarantee the achievement of the control objective without resorting to the exact knowledge of the inertial matrix. Moreover, the analysis of boundedness with respect to the entire signal in this closed system is performed by means of the Lyapunov stability theory. Ultimately, simulation results show that the proposed FTC strategy is efficient and powerful

ZG16 promotes T-cell mediated immunity through direct binding to PD-L1 in colon cancer

Abstract Immunotherapy using programmed cell death 1 (PD1) inhibitors has shown great efficacy in colorectal cancer patients harboring mismatch-repair-deficient (dMMR) and microsatellite instability-high (MSI-H) alterations. We previously showed a negative correlation of zymogen granule protein 16 (ZG16) with programmed death-ligand 1 (PD-L1) expression in patients with colorectal cancer. However, how ZG16 regulates PD-L1 expression is unclear. In this study, we showed that ZG16 can directly bind to glycosylated PD-L1 through its lectin domain, leading to PD-L1 degradation. Mutations on the lectin domain of ZG16 largely inhibit the interaction between ZG16 and PD-L1. Importantly, ZG16 overexpression suppressed tumor growth in two syngeneic mouse models through blockage of PD-L1 expression in cancer cells meanwhile suppression of PD1 expression in T cells. We also showed that ZG16 could improve the effect of chemotherapy and may be delivered as a protein to serve as an immune checkpoint inhibitor to promote T-cell mediated immunity

The efficacy and safety of entecavir in patients with chronic hepatitis B- associated liver failure: a meta-analysis

Background. The effectiveness of nucleoside analogue (NA) treatment in patients with chronic hepatitis B (CHB) -associated liver failure is still controversial. Severe lactic acidosis has been reported during entecavir (ETV) treatment in patients with impaired liver function.Aim. To investigate the rescuing efficacy and safety of ETV in patients with CHB-associated liver failure.Material and methods. A literature search was carried out to collect articles dated up to December, 2013 on ETV therapy for patients with CHB-associated liver failure. Risk ratio (RR) and mean difference (MD) were used to measure the effects. Survival rate was used as the primary efficacy measure. The safety of ETV was assessed.Results. Six randomized controlled trials were selected. The overall analysis revealed ETV significantly improved survival at 4 weeks (RR = 1.35; 95% CI [1.16, 1.57]; p < 0.0001), 8 weeks (RR = 1.33; 95% CI [1.07, 1.64]; p = 0.009), 12 weeks (RR = 1.68; 95% CI [1.24, 2.28]; p = 0.0008). Pooled data also showed beneficial effects of antiviral therapy compared with control for HBV DNA negative change (RR = 5.35; 95% CI [2.06, 13.88]; p = 0.0006), TBIL and PTA improvement (TBIL: MD = −69.36; 95% CI [−134.37, −4.36]; p = 0.04. PTA: MD = 16.26; 95% CI [8.59, 23.94]; p < 0.0001). No adverse effect was identified in the examined studies.Conclusion. Our results showed that antiviral therapy with ETV improved the short-term survival of patients with CHB-associated liver failure. In addition, ETV was well tolerated during the treatment period. Further studies are still needed to strengthen these results

MBAB-YOLO: A Modified Lightweight Architecture for Real-Time Small Target Detection

Current target detection methods have achieved high accuracy for detecting large and medium-sized targets. However, due to factors such as the small number of pixels and features available for targets in images, the detection performance for small targets is generally unsatisfactory. In addition, the real-time performance of target detection is also critical. In conclusion, a modified lightweight architecture for real-time small target detection, i.e., MBAB-YOLO, is proposed based on You Only Look Once (YOLO) model by combining channel-wise attention block, space-attention block and multi-branch-ConvNet (Convolutional Neural network) structure. Specifically, our method is more suitable for the rich scale information of small targets through proposed adaptive multi-receptive-field focusing, and then combines proposed blended attention block (BAB) to re-calibrate small target information to make it more prominent and improve the discriminability of small target features. Finally, extensive experiments have been conducted on the open source data set for the proposed real-time small target detection method, i.e., MBAB-YOLO. The results of ablation experiment and contrast experiment show that our method has excellent performance, not only with high detection accuracy, but also with fast detection speed. Compared with the various benchmark methods, it achieves a good trade-off between the two aspects mentioned above. In addition, this paper gives a comprehensive and detailed review of the current work about small target detection from different several perspectives, which can be used as a reference for future researchers