This paper examines the long-standing problem of linear quadratic regulation and stabilization for Itô stochastic systems with input delay. This problem remains a primary challenge because the ...separation principle does not hold for Itô stochastic systems. This paper presents a complete solution to the problem: 1) The (sufficient and necessary) solvability condition of the optimal control and the analytical controller are given based on the modified Riccati differential equation defined herein. 2) The sufficient and necessary stabilization condition in mean square sense is explored. We show that the Itô stochastic system with input delay is stabilized if and only if the modified algebraic Riccati equation developed in this paper has a unique positive-definite solution. The essential obstacle encountered in this paper concerns a Delayed Forward-Backward Stochastic Differential Equation (D-FBSDE), which is mathematical challenging.
This paper is concerned with the long-standing problems of linear quadratic regulation (LQR) control and stabilization for a class of discrete-time stochastic systems involving multiplicative noises ...and input delay. These fundamental problems have attracted resurgent interests due to development of networked control systems. An explicit analytical expression is given for the optimal LQR controller. More specifically, the optimal LQR controller is shown to be a linear function of the conditional expectation of the state, with the feedback gain based on a Riccati-ZXL difference equation. It is also shown that the system is stabilizable in the mean-square sense if and only if an algebraic Riccati-ZXL equation has a particular solution. These results are based on a new technical tool, which establishes a non-homogeneous relationship between the state and the costate of this class of systems, and the introduction of a new Lyapunov function for the finite-horizon optimal control design.
•Ag3PO4/WO3 were fabricated using a facile deposition-precipitation method.•The direction of charge transport between WO3 and Ag3PO4 is confirmed.•The enhanced photocatalytic activity of Ag3PO4/WO3 ...is due to the Z-scheme current.
The debated photocatalytic mechanism in the photocatalyst composite Ag3PO4/WO3 is explored by analyzing the electron flow direction between Ag3PO4 and WO3. Cubic phase WO3 nanosheets with a thickness of 10–20 nm are prepared using the sintering method at 200 °C and decorated by cubic Ag3PO4 particles using a practical deposition-precipitation method. Pure WO3 shows a strong adsorption activity for rhodamine B (RhB) and methylene blue (MB), but no adsorption activity for methyl orange (MO) and it shows no photocatalytic activity on these three dye molecules. Pure Ag3PO4 has no adsorption activity on RhB but shows a strong photocatalytic activity on RhB under visible light irradiation. As-prepared AW-x composites with different weight ratios show no adsorption activity but a high photocatalytic activity. However, after heat-treatment at 200 °C for 24 h, the composite catalysts show both a strong adsorption and photocatalytic activities on RhB. The results provide an indirect evidence that the electron flow direction is from WO3 to Ag3PO4, which thus supports the Z-scheme photocatalytic mechanism.
Metal-Organic Frameworks (MOFs) have attracted increasing attention in the field of energy storage owing to their high porosity, high specific surface area, high charge storage. However, the poor ...conductivity in most MOFs largely hinders their electrical properties. In this work, we developed an effective strategy to grow the conductive polyaniline (PANI) inside the pores of MIL-101 (labeled as PANI/MIL-101) to form a fixed interpenetrating network structure. The electron-rich imine group in PANI is chelated with the coordinatively unsaturated metal sites (CUS) in MIL-101 to form a relatively strong bonded complex and through other synergistic effects to enhance the conductivity and electrochemical properties. The resultant PANI/MIL-101 exhibited a superior high capacitance of 1197 F g−1 (i.e., 957.6C g−1) at 1 A g−1 in constant current charge and discharge test. The assembled flexible solid-state supercapacitor showed a favorable specific capacitance, power density and good cycling stability (a 81% capacitance retention rate over 10,000 cycles). It also demonstrates a good flexibility, as evidenced by a small capacitance loss of 10% after being subject to 1000 bending cycles at 180°. The PANI/MIL-101 nanocomposite showed great potential in energy storage device.
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•Polyaniline/MIL-101 composites have a fixed interpenetrating network structure.•The synergies between PANI and MIL-101 improve the electrochemical performance.•PANI/MIL-101 electrode can reach a specific capacitance of 1197 F g-1 at 1 A g−1.•The as-synthesized material shows high performance of flexible supercapacitor.
Human mesenchymal stem cell (hMSC) differentiation into osteoblasts has important clinical significance in treating bone injury, and the stiffness of the extracellular matrix (ECM) has been shown to ...be an important regulatory factor for hMSC differentiation. The aim of this study was to further delineate how matrix stiffness affects intracellular signaling through integrin α5/β1, FAK, and Wnt signaling, subsequently regulating the osteogenic phenotype of hMSCs.
hMSCs were cultured on tunable polyacrylamide hydrogels coated with fibronectin with stiffness corresponding to a Young's modulus of 13-16 kPa and 62-68 kPa. After hMSCs were cultured on gels for 1 week, gene expression of alpha-1 type I collagen, BGLAP, and RUNX2 were evaluated by real-time PCR. After hMSCs were cultured on gels for 24 h, signaling molecules relating to integrin α5 (FAK, ERK, p-ERK, Akt, p-Akt, GSK-3β, p-GSK-3β, and β-catenin) were evaluated by western blot analysis.
Osteogenic differentiation was increased on 62-68 kPa ECM, as evidenced by alpha-1 type I collagen, BGLAP, and RUNX2 gene expression, calcium deposition, and ALP staining. In the process of differentiation, gene and protein expression of integrin α5/β1 increased, together with protein expression of the downstream signaling molecules FAK, p-ERK, p-Akt, GSK-3β, p-GSK-3β, and β-catenin, indicating that these molecules can affect the osteogenic differentiation of hMSCs. An antibody blocking integrin α5 suppressed the stiffness-induced expression of all osteoblast markers examined. In particular, alpha-1 type I collagen, RUNX2, and BGLAP were significantly downregulated, indicating that integrin α5 regulates hMSC osteogenic differentiation. Downstream expression of FAK, ERK, p-ERK, and β-catenin protein was unchanged, whereas Akt, p-Akt, GSK-3β, and p-GSK-3β were upregulated. Moreover, expression of Akt and p-Akt was upregulated with anti-integrin α5 antibody, but no difference was observed for FAK, ERK, and p-ERK between the with or without anti-integrin α5 antibody groups. At the same time, expression of GSK-3β and p-GSK-3β was upregulated and β-catenin levels showed no difference between the groups with or without anti-integrin α5 antibody. Since Akt, p-Akt, GSK-3β, and p-GSK-3β displayed the same changes between the groups with or without anti-integrin α5 antibody, we then detected the links among them. Expression of p-Akt and p-GSK-3β was reduced effectively in the presence of the Akt inhibitor Triciribine. However, Akt, GSK-3β, and β-catenin were unchanged. These results suggested that expression of p-GSK-3β was regulated by p-Akt on 62-68 kPa ECM.
Taken together, our results provide evidence that matrix stiffness (62-68 kPa) affects the osteogenic outcome of hMSCs through mechanotransduction events that are mediated by integrin α5.
In this paper, we are concerned with the consensus of multi-agent systems with input delay. Among all standard static protocols that achieve the consensus for the multi-agent system under no input ...delay, we aim to find the maximum input delay such that the system remains consensusable under the same protocols. In the case of continuous-time systems, in view of the continuity of stability with respect to the time delay, the maximum delay margin for consensusability is given for scalar systems and vector systems with a single unstable open-loop pole. For scalar discrete-time systems, we show that the maximum delay margin for consensusability is strictly greater than zero if and only if the open-loop pole of the system is located in a specified interval.
With the development of nanotechnology, significant progress has been made in the design, and manufacture of nanoparticles (NPs) for use in clinical treatments. Recent increases in our understanding ...of the central role of macrophages in the context of inflammation and cancer have reinvigorated interest in macrophages as drug targets. Macrophages play an integral role in maintaining the steady state of the immune system and are involved in cancer and inflammation processes. Thus, NPs tailored to accurately target macrophages have the potential to transform disease treatment. Herein, we first present a brief background information of NPs as drug carriers, including but not limited to the types of nanomaterials, their biological properties and their advantages in clinical application. Then, macrophage effector mechanisms and recent NPs-based strategies aimed at targeting macrophages by eliminating or re-educating macrophages in inflammation and cancer are summarized. Additionally, the development of nanocarriers targeting macrophages for disease diagnosis is also discussed. Finally, the significance of macrophage-targeting nanomedicine is highlighted, with the goal of facilitating future clinical translation.
Finding reliable markers for predicting the efficacy of immunotherapy is urgently needed. We sought to investigate the association between serum microRNAs (miRNAs) and checkpoint inhibitor response ...in non-small cell lung cancer (NSCLC). Discovery assay with sera miRNA profiling was performed, demonstrating 27 sera miRNAs (relative fold >2, p < .05), 22 higher expressed and 5 lower expressed miRNAs, were differentially expressed in 19 responders compared to those in 27 non-responders. Further validation validated miR-93, −138-5p, −200, −27a, −424, −34a, −28, −106b, −193a-3p, and -181a were significantly higher expressed (p < .01) in an independent cohort of 17 responders vs. 17 non-responders. Longitudinally, responders had increased sera expression levels of miR-93, −138-5p, −200, −27a, −424, −34a, −28, −106b, −193a-3p, and -181a from pre-treatment to post-treatment (p < .01). More importantly, statistically significant improvement in PFS of patients was associated with the 10-high expressed miRNA pattern (median PFS of 6.25 versus 3.21 months, p < .001; hazard ratio, HR, 0.45; 95% CI, 0.25–0.76). Further OS improvement was also significantly associated with the 10-high expressed miRNA pattern in responders versus non-responders (median OS of 7.65 versus 3.2 months, p < .001, HR, 0.39; 95% CI, 0.15–0.68). In conclusion, these results demonstrated that alterations in circulating miRNAs are associated with the response and outcome in NSCLC patients treated with anti-PD1 drugs.
•22 higher expressed and 5 lower expressed miRNAs in 19 responders compared to those in 27 non-responders.•miR-93, −138-5p, −200, −27a, −424, −34a, −28, −106b, −193a-3p, and -181a were significantly higher expressed in responders vs. 17 non-responders.•Significant improvement in PFS of patients was associated with the 10-high expressed miRNA pattern.•OS improvement was also significantly in responders versus non-responders.
This technical note revisits the open-loop Stackelberg strategy for a two-player game. By introducing a new costate, which captures the future information of the control input, we present a necessary ...and sufficient condition for the existence and uniqueness of the two-player game. The optimal strategy is designed in terms of three decoupled and symmetric Riccati equations which improves the existing results greatly on computation.
This paper is concerned with both difference and differential leader-follower games with time delay. The problem remains challenging although the leader-follower game for delay-free system has been ...well studied in the past decades. The main obstacle encountered is the noncausality of strategy design caused by the delay. The key technique developed to overcome the difficulty is the introduction of the new co-states which capture the future information of the control and the new state which contains the past effects. The novel contributions of this paper are as follows. First, the sufficient and necessary solvability condition is given to ensure the existence of a unique open-loop Stackelberg strategy for the difference game. Second, the open-loop strategy is explicitly obtained in terms of decoupled and symmetric Riccati equations. Last but not least, a unique strategy for continuous time systems is also given by applying the techniques developed in this paper.
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