New Approach to Observer-Based Finite-Time H∞ Control of Discrete-Time One-Sided Lipschitz Systems with Uncertainties

This paper investigates the finite-time H∞ control problem for a class of nonlinear discrete-time one-sided Lipschitz systems with uncertainties. Using the one-sided Lipschitz and quadratically inner-bounded conditions, the authors derive less conservative criterion for the controller design and observer design. A new criterion is proposed to ensure the closedloop system is finite-time bounded (FTB). The sufficient conditions are established to ensure the closed-loop system is H∞ finite-time bounded (H∞ FTB) in terms of matrix inequalities. The controller gains and observer gains are given. A numerical example is provided to demonstrate the effectiveness of the proposed results

Perceiving the World: Question-guided Reinforcement Learning for Text-based Games

Text-based games provide an interactive way to study natural language processing. While deep reinforcement learning has shown effectiveness in developing the game playing agent, the low sample efficiency and the large action space remain to be the two major challenges that hinder the DRL from being applied in the real world. In this paper, we address the challenges by introducing world-perceiving modules, which automatically decompose tasks and prune actions by answering questions about the environment. We then propose a two-phase training framework to decouple language learning from reinforcement learning, which further improves the sample efficiency. The experimental results show that the proposed method significantly improves the performance and sample efficiency. Besides, it shows robustness against compound error and limited pre-training data.Comment: ACL2022, fix some typo

Id2 promotes the invasive growth of MCF-7 and SKOV-3 cells by a novel mechanism independent of dimerization to basic helix-loop-helix factors

<p>Abstract</p> <p>Background</p> <p>Inhibitor of differentiation 2 (<it>Id2</it>) is a critical factor for cell proliferation and differentiation in normal vertebrate development. Most of the biological function of Id2 has been ascribed to its helix-loop-helix motif. Overexpression of Id2 is frequently observed in various human tumors, but its role for invasion potential in tumor cells is dispute. We aimed to reveal the role of Id2 in invasion potential in poorly invasive and estrogen receptor α (ERα)-positive MCF-7 and SKOV-3 cancer cells.</p> <p>Methods</p> <p>MCF-7 and SKOV-3 cells were stably transfected with the wild-type, degradation-resistant full-length or helix-loop-helix (HLH)-deleted Id2, respectively. Protein levels of Id2 and its mutants and E-cadherin were determined by western blot analysis and mRNA levels of Id2 and its mutants were determined by RT-PCR. The effects of Id2 and its mutants on cell proliferation were determined by [³H]-thymidine incorporation assay and the 3- [4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) dye method. The <it>in vitro </it>invasion potential of cells was evaluated by Transwell assay. Cell motility was assessed by scratch wound assay. The promoter activity of <it>E-cadherin </it>was determined by cotransfection and luciferase assays.</p> <p>Results</p> <p>Ectopic transfection of the wild-type Id2 markedly increased the protein and mRNA expression of <it>Id2 </it>in MCF-7 and SKOV-3 cells; the protein level but not mRNA level was further increased by transfection with the degradation-resistant Id2 form. The ectopic expression of Id2 or its mutants did not alter proliferation of either MCF-7 or SKOV-3 cells. Transfection of the wild-type Id2 significantly induced the invasion potential and migratory capacity of cells, which was further augmented by transfection with the degradation-resistant full-length or HLH-deleted Id2. E-cadherin protein expression and transactivation of the proximal E-cadherin promoter were markedly suppressed by the degradation-resistant full-length or HLH-deleted Id2 but not wild-type Id2. Ectopic expression of E-cadherin in MCF-7 and SKOV-3 cells only partially blunted the invasion potential induced by the degradation-resistant HLH-deleted Id2.</p> <p>Conclusion</p> <p>Overexpression of Id2 in ERα-positive epithelial tumor cells indeed increases the cells' invasive potential through a novel mechanism independent of dimerization to basic helix-loop-helix factors. E-cadherin contributes only in part to Id2-induced cell invasion when Id2 is accumulated to a higher level in some specific cell types.</p

GRD: A Generative Approach for Interpretable Reward Redistribution in Reinforcement Learning

A major challenge in reinforcement learning is to determine which state-action pairs are responsible for future rewards that are delayed. Return Decomposition offers a solution by redistributing rewards from observed sequences while preserving policy invariance. While the majority of current approaches construct the reward redistribution in an uninterpretable manner, we propose to explicitly model the contributions of state and action from a causal perspective, resulting in an interpretable return decomposition. In this paper, we start by studying the role of causal generative models in return decomposition by characterizing the generation of Markovian rewards and trajectory-wise long-term return and further propose a framework, called Generative Return Decomposition (GRD), for policy optimization in delayed reward scenarios. Specifically, GRD first identifies the unobservable Markovian rewards and causal relations in the generative process. Then, GRD makes use of the identified causal generative model to form a compact representation to train policy over the most favorable subspace of the state space of the agent. Theoretically, we show that the unobservable Markovian reward function is identifiable, as well as the underlying causal structure and causal models. Experimental results show that our method outperforms state-of-the-art methods and the provided visualization further demonstrates the interpretability of our method

The effect of balance and gait training on specific balance abilities of survivors with stroke: a systematic review and network meta-analysis

BackgroundStroke, which is a common clinical cerebrovascular disease, causes approximately 83% of survivors to suffer from balance impairments. Balance and gait training (BGT) is widely used to restore balance in patients with stroke. However, its wide variety presents clinicians with a dilemma when selecting interventions. This study aimed to compare and rank BGT interventions by quantifying information based on randomized controlled trials (RCTs).MethodsWe conducted a network meta-analysis (NMA) of non-gait-trained controls and head-to-head RCTs and compared the effects of 12 BGT interventions. A total of nine literature databases, including Medline, Embase, Cochrane Library, Web of Science, Scopus, SPORTDiscus, ClinicalTrials.gov, CNKI, and Chinese biomedical literature databases, were searched from their database inception to August 2023. Two authors independently selected studies and extracted data. The difference in outcomes, which were expressed as standardized mean differences and confidence intervals (CIs) of 95%, were explored in this meta-analysis.ResultsA total of 66 studies with 1,933 participants were included. Effect size estimates showed that not all BGT interventions were more effective than controls, with treadmill training as the least effective for balance test batteries (SMD = −0.41, 95% CI [−1.09, 0.27]) and proactive balance (SMD = −0.50, 95% CI [−1.14, 0.14]). Body-weight-supported treadmill training with external stimulation was most effective for proactive balance and dynamic steady-state balance (SMD = 1.57, 95% CI [−0.03, 3.16]); SMD = 1.18, 95% CI [0.67, 1.68]. Virtual reality gait training (SMD = 1.37, 95% CI [0.62, 2.11]) had the best effect on improving balance test batteries, while dual-task BGT (SMD = 1.64, 95% CI [0.50, 2.78]) had the best effect on static steady-state balance. After analyses for possible impact covariates, the findings through the outcomes did not change substantially. Confidence in the evidence was generally low or very low.ConclusionThis NMA suggested that virtual reality gait training was the most effective BGT modality for improving balance test batteries. Body-weight support treadmill training with external stimulation was the most effective for improving active and dynamic balance. In addition, dual-task BGT was the best choice for improving static balance. However, balance is a multidimensional concept, and patients’ different needs should be considered when selecting BGT.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022316057, ID: CRD42022316057

Far-field transient absorption nanoscopy with sub-50 nm optical super-resolution

Nanoscopic imaging or characterizing is the mainstay of the development of advanced materials. Despite great progress in electronic and atomic force microscopies, label-free and far-field characterization of materials with deep sub- wavelength spatial resolution has long been highly desired. Herein, we demonstrate far-field super-resolution transient absorption (TA) imaging of two-dimensional material with a spatial resolution of sub-50 nm. By introducing a donut- shaped blue saturation laser, we effectively suppress the TA transition driven by near-infrared (NIR) pump–probe photons, and push the NIR-TA microscopy to sub-diffraction-limited resolution. Specifically, we demonstrate that our method can image the individual nano-grains in graphene with lateral resolution down to 36 nm. Further, we perform super-resolution TA imaging of nano-wrinkles in monolayer graphene, and the measured results are very consistent with the characterization by an atomic force microscope. This direct far-field optical nanoscopy holds great promise to achieve sub-20 nm spatial resolution and a few tens of femtoseconds temporal resolution upon further improvement and represents a paradigm shift in a broad range of hard and soft nanomaterial characterization

Toxoplasma gondii cathepsin proteases are undeveloped prominent vaccine antigens against toxoplasmosis

BACKGROUND: Toxoplasma gondii, an obligate intracellular apicomplexan parasite, infects a wide range of warm-blooded animals including humans. T. gondii expresses five members of the C1 family of cysteine proteases, including cathepsin B-like (TgCPB) and cathepsin L-like (TgCPL) proteins. TgCPB is involved in ROP protein maturation and parasite invasion, whereas TgCPL contributes to proteolytic maturation of proTgM2AP and proTgMIC3. TgCPL is also associated with the residual body in the parasitophorous vacuole after cell division has occurred. Both of these proteases are potential therapeutic targets in T. gondii. The aim of this study was to investigate TgCPB and TgCPL for their potential as DNA vaccines against T. gondii. METHODS: Using bioinformatics approaches, we analyzed TgCPB and TgCPL proteins and identified several linear-B cell epitopes and potential Th-cell epitopes in them. Based on these results, we assembled two single-gene constructs (TgCPB and TgCPL) and a multi-gene construct (pTgCPB/TgCPL) with which to immunize BALB/c mice and test their effectiveness as DNA vaccines. RESULTS: TgCPB and TgCPL vaccines elicited strong humoral and cellular immune responses in mice, both of which were Th-1 cell mediated. In addition, all of the vaccines protected the mice against infection with virulent T. gondii RH tachyzoites, with the multi-gene vaccine (pTgCPB/TgCPL) providing the highest level of protection. CONCLUSIONS: T. gondii CPB and CPL proteases are strong candidates for development as novel DNA vaccines