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This paper investigates the problem of sliding mode control (SMC) design under the finite-state Markov digital block-fading channels. Before transmitting through the independent digital channels, the output measurements are first quantized through logarithmic quantizers. Then, p independent finite-state hidden Markov models are introduced to model the time-varying effects subject to error-free packet arrival rates. A new one-to-one mapping rule is proposed for reformulating p Markov chains into a new Markov chain. By means of the information from the mode detectors, we construct the detected mode-dependent state observer and the corresponding sliding mode controller. Both the exponential mean-square stability of the closed-loop system and the reachability of the specified sliding surface are analyzed through the fading mode-dependent Lyapunov function method. Furthermore, by adopting the binary genetic algorithm (GA), an optimizing quasi-sliding mode is further achieved. Finally, an illustrative example is provided to verify the effectiveness of the proposed method.

Metabolic stability of proteins plays a vital role in various dedicated cellular processes. Traditional methods of measuring the metabolic stability are time-consuming and expensive. Therefore, we developed a more efficient computational approach to understand the protein dynamic action mechanisms in biological process networks. In this study, we collected 341 short-lived proteins and 824 non-short-lived proteins from U2OS; 342 short-lived proteins and 821 non-short-lived proteins from HEK293T; 424 short-lived proteins and 1153 non-short-lived proteins from HCT116; and 384 short-lived proteins and 992 non-short-lived proteins from RPE1. The proteins were encoded by GO and KEGG enrichment scores based on the genes and their neighbors in STRING, resulting in 20,681 GO term features and 297 KEGG pathway features. We also incorporated the protein interaction information from STRING into the features and obtained 19,247 node features. Boruta and mRMR methods were used for feature filtering, and IFS method was used to obtain the best feature subsets and create the models with the highest performance. The present study identified 42 features that did not appear in previous studies and classified them into eight groups according to their functional annotation. By reviewing the literature, we found that the following three functional groups were critical in determining the stability of proteins: synaptic transmission, post-translational modifications, and cell fate determination. These findings may serve as a valuable reference for developing drugs that target protein stability.

The objective of this study was to synthesize and characterize cystamine dihydrochloride (CYS) crosslinked carboxymethyl cellulose/quaternized chitosan (CMC/HACC) composite hydrogel film. Firstly, the glycidyl-based quaternary ammonium chitosan derivative (HACC) was synthesized using nucleophilic substitution reaction. Then HACC was analyzed by FTIR, 1HNMR spectra and the composite films at different blending ratio of CMC and HACC were studied by rheology measurement, mechanical and swelling tests. When the composite films were prepared under optimized conditions (CMC: HACC = 7:1), they showed excellent mechanical properties (with improved 93.3% tensile strength and 2.3% elongation at break) and swellability (equilibrium swelling ratio increased 270%) compared to pure CMC film. 5-Fluorouracil (5-FU) was used as drug model which has broad-spectrum anticancer properties. The 5-FU/CMC/HACC composite films showed redox and pH responsive of drug release properties along with well biocompatibility. The in vitro cytotoxicity and cell apoptosis studies showed the drug loaded composite films with obvious toxicity against HepG2 cells especially in the presence of GSH. In addition, CMC/HACC composite films showed good antibacterial against S. aureus and E. coli, while pure CMC film had no antimicrobial activities. It can be concluded that CMC/HACC composite films can be potentially used as targeted drug delivery system.

In this work, we investigate the finite-time boundedness (FTB) problem for a class of continuous-time uncertain systems via sliding mode control (SMC) method. A dynamic event-triggered scheme is introduced to determine whether the measurement output will be transmitted. And then, a state observer is designed by means of the transmitted output information, based on which a sliding surface in the estimation space is construct. It is shown that the corresponding SMC law can drive the system trajectories onto the specified sliding surface in a finite (possibly short) time. Meanwhile, a partitioning strategy is introduced to analyze the FTB over both reaching phase and the sliding motion, respectively. Finally, a numerical simulation is given.

Transfer learning (TL) is a machine learning (ML) method in which knowledge is transferred from the existing models of related problems to the model for solving the problem at hand. Relational TL enables the ML models to transfer the relationship networks from one domain to another. However, it has two critical issues. One is determining the proper way of extracting and expressing relationships among data features in the source domain such that the relationships can be transferred to the target domain. The other is how to do the transfer procedure. Knowledge graphs (KGs) are knowledge bases that use data and logic to graph-structured information; they are helpful tools for dealing with the first issue. The proposed relational feature transfer learning algorithm (RF-TL) embodies an extended structural equation modelling (SEM) as a method for constructing KGs. Additionally, in fields such as medicine, economics, and law related to people’s lives and property safety and security, the knowledge of domain experts is a gold standard. This paper introduces the causal analysis and counterfactual inference in the TL domain that directs the transfer procedure. Different from traditional feature-based TL algorithms like transfer component analysis (TCA) and CORelation Alignment (CORAL), RF-TL not only considers relations between feature items but also utilizes causality knowledge, enabling it to perform well in practical cases. The algorithm was tested on two different healthcare-related datasets — sleep apnea questionnaire study data and COVID-19 case data on ICU admission — and compared its performance with TCA and CORAL. The experimental results show that RF-TL can generate better transferred models that give more accurate predictions with fewer input features.

Excess cholesterol deposition in lysosomes may result in lysosomal stress and dysfunction. Here, we focus on the role of lysosome membrane protein 2 (LIMP2) in relieving the lysosomal stress caused by excess cholesterol and the mechanism that regulate its expression.Cholesterol enrichment in lamprey liver tissue was evaluated by RNA transcriptome data analysis, RT-qPCR, HE, and Oil Red O staining. Gene markers of autophagy and cholesterol synthesis were determined by western blot or RT-qPCR. Lysosomal morphology and pH value was measured by confocal observation or flow cytometry. Dual-Luciferase reporter assay was performed to test the expression regulation relationship.We report that lamprey limp2 (L-limp2) is evolutionarily highly conserved with human LIMP2 (H-LIMP2). The biological function of L-limp2, consistent with H-LIMP2, includes maintaining lysosomal morphology, modulating autophagy, and aiding cholesterol efflux from lysosomes. Furthermore, we find that both L-limp2 and H-limp2 can restore cholesterol-induced elevation of lysosomal pH and impaired autophagic flux. We demonstrate that lamprey transcription factor binding to IGHM enhancer 3 (L-TFE3) can bind with coordinated lysosomal expression and regulation (CLEAR) elements on the L-limp2 promoter and regulate its expression. Moreover, this regulatory relationship is also available in humans. Taken together, the present study demonstrates that the evolutionarily conserved TFE3-LIMP2 axis may have a protective role against the impaired lysosomal function caused by excess cholesterol.The protective effect of TFE3-LIMP2 axis against cholesterol-triggered lysosomal stress may provide a new target for the treatment of diseases caused by excessive cholesterol accumulation in lysosomes.

Heparan sulfate (HS) and heparin, representative members of the glycosaminoglycans, possess distinct biological functions in terms of their specific interactions with hundreds of binding proteins. However, the structural properties of HS and heparin are complex due to their variable repeating motifs, different chain lengths and sulfation patterns. A concise chemoenzymatic approach has been developed to obtain well-defined low molecular weight (LMW) HS analogues. Pasteurella multocida heparosan synthase-2 (PmHS2) was utilized to fabricate the HS backbones with controllable chain lengths ranging from 14mer to 26mer. Moreover, regioselective and overall sulfation were conducted by chemical approach. The persulfated HS analogues exhibited more potent beta-site amyloid precursor protein (APP)-cleaving enzyme-1 (BACE-1) inhibitory activity than heparin and enoxaparin, and enhanced BACE-1 inhibitions were also found with the increasing molecular size of the HS analogues. This approach supplies the promising LMW HS analogues for the potential development of novel anti-Alzheimer's drugs.

In this study, historical surface solar radiation (1850–2005) and future photovoltaic power output (2006–2100) are analyzed to investigate the spatial distribution and long-term variation in global solar energy based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) models and the Global Energy Balance Archive (GEBA) database. The results show that global mean surface solar radiation significantly decreased by 0.014 W m−2 year−1 in 1850–2005. According to the Model for Interdisciplinary Research on Climate (MIROC5), surface solar radiation significantly decreased by 3.42 W m−2 year−1 in 1951–1992 and increased by 4.75 W m−2 year−1 in 1993–2005. Global dimming and brightening were observed before and after the 1990s, respectively. The transition of surface solar radiation from dimming to brightening in Europe and the southeastern United States was detected in the 1980s. Stations in Northeast China, Japan, Southeast Africa, the Middle East, and the west coast of India all showed renewed decreasing trends after the 1990s. The direct and indirect effects of anthropogenic aerosols and cloudiness in different periods and regions were the main causes of the changes. To better understand the utilization of global solar energy, global potential photovoltaic power outputs were estimated in future scenarios with an empirical model. Significant increases in potential photovoltaic power are expected in East Asia, Europe, Central Africa and Central America in 2006–2100. The largest increase is expected in central China, where increases are occurring at 3 kWh m−2 year−1. Significantly decreasing potential photovoltaic power is observed in North Africa, the Middle East, Central Asia and Australia. The greatest decrease is observed in the Tibetan Plateau area (approximately −3.0 kWh m−2 year−1 in 2006–2100). With respect to the global distribution of potential photovoltaic power output, large quantities of photovoltaic power are distributed in the northern and southern parts of Africa, the Middle East, the Tibetan Plateau area, the west coasts of North and South America and most of Australia. The yearly mean sum photovoltaic power in these regions is larger than 2000 kW h m−2. Due to the long-term decreasing photovoltaic power (0.67 kWh m−2 year−1) expected worldwide in 2006–2100, effective and rational utilization of solar energy is of great importance.

Photocatalytic technology has been widely adopted to address the issue of air pollution. The separation of photogenerated carriers and the activation of reactants on catalyst surface are the main factors that affect the photocatalytic efficiency. Here, the phosphate/potassium (PO4/K) co-functionalized carbon nitride (labeled as PO4-CN-K) was synthesized via a one-step in situ co-pyrolysis of thiourea and potassium phosphate. The unique electronic structure of PO4-CN-K could significantly improve the performance of photocatalytic NO purification. The enhanced activity of PO4-CN-K can be attributed to the promoted activation capacity for O2, NO and H2O on the catalyst surface, the decreased of carriers recombination, benefiting from the co-functionalization of phosphate groups on the surface of CN and the construction of K channels between CN layers. The photocatalytic NO conversion pathway is disclosed through time-dependent in situ FT-IR, indicating that PO4-CN-K can efficiently convert NO molecules into harmless nitrate via the NO→NO+→nitrate/nitrite routes. The research provides a novel strategy to impel the development of photocatalytic technology for efficient air purification.

Bi metal deposited hexagonal BiPO4 with the exposure of {102} facet (Bi-HBPO-102) and Bi metal deposited monoclinic BiPO4 with the exposure of {120} facet (Bi-MBPO-120) were prepared by chemical deposition method and solvothermal approach, respectively. The as-prepared catalysts presented more efficient photocatalytic activity of NOx removal than pure BiPO4 (2.0% for BiPO4, 51.4% for Bi-HBPO-102 and 36.2% for Bi-MBPO-120) under visible light irradiation, which can be attributed to the synergistic effects endowed by the phosphate defect, the surface plasmon resonance (SPR) effect of Bi metal and the facet effect. The existence of phosphate defect was confirmed by the XPS and solid state EPR technique. The DFT calculation revealed the position of phosphate and the phosphate defect induced the formation of an intermediate level within the forbidden band to allow efficient charge transfer from valence band to conduction band. Moreover, the Bi metal would act as the electron contributor and electron conductor which facilitated the charge carriers separation. Therefore, a new charge transfer pathway can be certified on account of the fact that the covalent loop was evidently generated both at the interface and along with the path of [Bi2O2]2+ → Bi metal → PO43− on the Bi@BiPO4. More importantly, the Bi-HBPO-102 with exposure of {102} facet exhibited higher photocatalytic activity than the Bi-MBPO-120 with exposed {120} facet. The {102} facet with the stronger distorted PO4 tetrahedron and the lower potential energy barrier (-17.5eV) contributed to the contacted interface with the more efficient charge transfer, which promoted the generation of active radicals on {102} facet. Additionally, for Bi-HBPO-102, the reaction intermediate NO+ can be observed with in situ DRIFTS, which facilitated the activation of NO via the formation of NO+ to promote the oxidation of NO into final products. Herein, a new strategy for tailoring the charge transfer pathway was developed to enhance the photocatalytic performance and a new photocatalytic reaction mechanism for photocatalytic NOx removal was proposed. This work could provide new insights into the modification of photocatalysts and mechanistic understanding of the gas-phase photocatalytic reaction mechanism.

COVID-19 has spread to all countries around the world after it was first discovered in Wuhan of China at the end of 2019. It is caused by a novel coronavirus called SARS-CoV-2 with much semblance to SARS-CoV including the sequence homology and disease symptoms. It is reported to be more infectious than SARS-CoV due to higher binding affinities between its spike protein and the ACE2 receptor on cell surface. Despite this, its case fatality rate is much lower compared with that of SARS-CoV although it varies in different countries. However, the case fatality rate increases steadily with age and it is reported to be the highest in aged COVID-19 male patients in almost all countries. Consistent with these, females have higher antiviral immune responses. Males and females are different in inflammatory response and aberrantly hyperactive cytokines are the main lethal causes of COVID-19. Interestingly, the gene encoding the ACE2 receptor protein and some genes encoding the immune regulatory proteins such as TLR7 are located on X chromosome which is subject to X chromosome inactivation and sex hormone regulation. These may account for some sex-dependent immune responses and lethality observed in COVID-19 patients. In general, children are less likely to be infected with SARS-CoV-2 and only less than 1% of pediatric COVID-19 patients may die of COVID-19. However, the most severe pediatric cases become multisystem inflammatory syndrome that is similar to Kawasiki disease with features of viral infection. Since most infected kids were boys in China, there may be sex-dependent immune response in pediatric COVID-19 cases as well.

Background: The COVID-19 epidemic is a current major public health emergency. However, little is known about the psychological impact on adolescents during this pandemic. We aimed to assess the prevalence and influencing factors of depression, anxiety and posttraumatic growth (PTG) among adolescents in a large sample study. Methods: The cross-sectional study collected demographic data and mental health measurements from 175,416 adolescents covered all provinces and autonomous regions in mainland of China from February 23-29, 2020. The status of depression, anxiety and PTG were assessed by patient health questionnaire 9-item, generalized anxiety disorder questionnaire 7-item and post-traumatic growth inventory. Findings: The prevalence of depression, anxiety and PTG in adolescents was 35·9%, 28·0% and 45·6%, respectively. The prevalence of depression and anxiety in slight or severe epidemic areas were similar. Regression analysis showed that female and older age were associated with higher levels of depression, anxiety and lower levels of PTG. Having symptoms related to COVID-19, excessive attention to epidemic information, living in urban or severe epidemic areas and conflicting with parents during home quarantine were risk factors of depression, anxiety and PTG. The frequently communication with peers, exercise and receiving public welfare psychological assistance were protective factors. Poor family economic situation was significantly risk factor of depression and PTG. Interpretation: Our findings suggested that positive and negative psychological reactions coexist on adolescents in the face of pandemic. The factors associated with psychological problems and PTG which provided strategic guidance for maintaining adolescent’s mental health in China as well as worldwide during any public pandemics such as COVID-19. Funding Statement: This research was supported by the National Natural Science Foundation of China (81773536) to Prof. Yanjie Yang. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The present study was approved by the Ethics Committee of Harbin Medical University (HMUIRB20200002). Each participant provided online informed consent to participate in the study.

Mental experiences can become long-term memories if the hippocampal activity patterns that encode them are broadcast during network oscillations. The activity of inhibitory neurons is essential for generating these neural oscillations, but molecular control of this process during learning remains unknown. Here we show that hippocampal oscillatory strength positively correlates with excitatory monosynaptic drive onto inhibitory neurons (E→I) in vivo. To establish direct causality between them, we identified γCaMKII as the long-sought mediator of long-term potentiation for E→I synapses (LTPE→I), which enabled the genetic manipulation of experience-dependent E→I synaptic input/plasticity. Deleting γCaMKII in parvalbumin interneurons not only selectively eliminated LTPE→I, but also disrupted experience-driven oscillation strengthening in theta and gamma rhythmicity. Consequently, this manipulation impaired long-term memory, for which the kinase activity of γCaMKII was required. Taken together, our data suggest that E→I synaptic plasticity, exemplified by LTPE→I, plays a gatekeeping role in tuning experience-dependent brain rhythms and mnemonic function.

A novel geothermal power system integrated with a biomass-fired cogeneration plant has been developed, which feeds the obtained geothermal energy into the steam cycle of the biomass plant. Under the cogeneration scenario, the geothermal water provides heat to the supply-water for district heating together with the extraction steam of the turbine, while in the power generation scenario, the geothermal water is employed to warm the feedwater of the biomass plant. Consequently, much extraction steam of the turbine can be saved to produce additional electricity that can be regarded as geothermal energy-based electricity. Based on a 35 MW biomass cogeneration plant, the thermodynamic and economic performance of the proposed system was evaluated, and the effects of the main parameters were investigated as well. The results indicated that the geothermal power generation efficiency can reach 25.47% or 5.62% under the cogeneration mode or power generation mode. In a whole year, 16935.48 MWh electricity can be yielded from geothermal energy with an annual geothermal power generation efficiency of 17.08%. The levelized cost of geothermal energy-based electricity is only 0.0329 $/kWh when adopting the new design. Generally, the novel concept is quite advantageous from both the thermodynamic and economic perspectives.

NH3 can be used as an H2 energy carrier or an alternative carbon-free fuel because of its high volumetric energy density and easy liquefaction, which leads to convenient and economic transportation and storage within the global energy network. However, the combustion of NH3 is associated with some practical challenges, such as weak reactivity and high NOx emission. In this study, Moderate & Intense Low Oxygen Dilution (MILD) combustion of NH3 was conducted experimentally in a novel burner. The heated and diluted air was produced by burning a premixed lean CH4 mixture using a metal fiber burner installed at the bottom of the combustion chamber and NH3 was injected into the furnace by 20 nozzles oppositely installed on the sidewalls of the combustion chamber at 40 mm above its bottom. A total of 20 cases were investigated in the present work, including premixed combustion of CH4 and CH4/NH3, and MILD combustion of NH3, under various conditions. The Chemical reactor network (CRN) in the ANSYS Chemkin 17.0 and the HUST mechanism were used to simulate and analyze the NO formation mechanism under several experimental conditions. The experimental results showed that the NH3 MILD combustion significantly reduces the NOx emissions. The NOx reduction kinetics and the impact of NH3 flow rate and the equivalence ratio on NO emission in NH3 MILD combustion were analyzed in detail.

In addition to generate electricity, proton exchange membrane fuel cells (PEMFCs) also produce a considerable quantity of waste heat, which may affect the cell normal operation if not removed immediately. To remove and harvest the waste heat, a novel combined system that couples an elastocaloric cooler (ECC) to a PEMFC is proposed, where the ECC harnesses the waste heat from the PEMFC for cooling purposes. Including thermodynamic and electrochemical irreversible losses, mathematical expressions for efficiency and power output of the combined system are obtained. The operating current density region of the PEMFC allowing the ECC to work is determined and the optimum operation regions for power output and efficiency of the combined system are specified. Moreover, numerical calculations indicate that the equivalent maximum power density and its corresponding efficiency of the combined system can be, respectively, increased by 163.2 % and 64.2 % in comparison with that of the single PEMFC. Exhaustive parametric studies are further undertaken to reveal how the combined system performance is associated with some key design parameters and operation conditions, such as operating temperature, operating pressure, proton exchange membrane thickness, environment temperature, cross-sectional area ratio, length ratio and thermodynamic losses related parameters. The results may offer some theoretical bases for designing and running such a real combined system and open up a new avenue to harvest waste heat from PEMFCs.

A hybrid design that combines waste gasification and coal-fired power generation has been proposed for improving the waste-to-energy process. In the integrated scheme, municipal solid waste is fed into the plasma gasifier and converted into syngas, which is precooled by the feedwater of the coal power plant and then conveyed directly into the coal-fired boiler for combustion. Consequently, the syngas energy is exploited for electricity production through the steam cycle of the coal power plant. The benefits of this concept were examined based on a 4.0 kg/s (waste feed rate) plasma gasifier and a 660 MW coal power plant in the thermodynamic and economic aspects. Once the net power generated from coal remains constant, 16.12 MW net power can be produced from waste with a net waste-to-electricity efficiency of 35.16% in the hybrid design. Only 4.58 years is required to recover the initial investment of the proposed waste-to-energy system, and a net present value of 40,341.00 k$ can be achieved in its 25-year lifetime. Besides, the effects of the waste moisture content, equivalence ratio, and gasification temperature on the performance of the hybrid system were discussed.

The availability of freshwater has been and remains a crucial concern in westerlies-dominated arid Central Asia. Understanding precipitation changes in this area and the underlying mechanisms, therefore, is of great importance. This study explores precipitation changes in Central Asia (35°–50° N and 50°–70° E) since the Last Glacial Maximum (LGM) and their control factors using results from the “Simulation of Transient Climate Evolution over the last 21,000 years”. Transient simulations reveal that a wet climate occurred during the LGM, the Bolling-Allerod warm period, and the middle Holocene, and a dry climate occurred during Heinrich event 1, the Younger Dryas, and the early Holocene in this area. Model results are in good agreement with proxy records since the last deglaciation. These changes were mainly controlled by Earth's orbital parameters, meltwater discharges into the oceans and continental ice sheets. The contribution of GHG concentrations to precipitation changes was minor. External forcing factors influenced the precipitation mainly through affecting the water vapor input from the North Atlantic and Mediterranean Sea, and vertical motions of the atmosphere over Central Asia. The North Atlantic Oscillation was an important atmospheric bridge connecting the external forcings to precipitation changes in Central Asia. There were complex relationships between precipitation changes in Central Asia and East Asia since the LGM due to the differences of the dominating factors.

Both MnOx and g-C3N4 have been proved to be active in the catalytic oxidation of NO, and their individual mechanisms for catalytic NO conversion have also been investigated. However, the mechanism of photo-thermal catalysis of the MnOx/g-C3N4 composite remains unresolved. In this paper, MnOx/g-C3N4 catalysts with different molar ratios were synthesized by the precipitation approach at room temperature. The as-prepared catalysts exhibit excellent synergistic photo-thermal catalytic performance towards the purification of NO in air. The MnOx/g-C3N4 catalysts contain MnOx with different valence states on the surface of g-C3N4. The thermal catalytic reaction for NO oxidation on MnOx and the photo-thermal catalytic reaction on 1:5 MnOx/g-C3N4 were investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results show that light exerted a weak effect on NO oxidation over MnOx, and it exerted a positive synergistic effect on NO conversion over 1:5 MnOx/g-C3N4. A synergistic photo-thermal catalytic cycle of NO oxidation on MnOx/g-C3N4 is proposed. Specifically, photo-generated electrons (e−) are transferred to MnOx and participate in the synergistic photo-thermal reduction cycle (Mn4+→Mn3+→Mn2+). The reverse cycle (Mn2+→Mn3+→Mn4+) can regenerate the active oxygen vacancy sites and inject electrons into the g-C3N4 hole (h+). The active oxygen (O−) was generated in the redox cycles among manganese species (Mn4+/Mn3+/Mn2+) and could oxidize the intermediates (NOH and N2O2−) to final products (NO2− and NO3−). This paper can provide insightful guidance for the development of better catalysts for NOx purification.