Load frequency control (LFC) of modern power systems tends to employ open communication networks to transmit measurement/control signals. Under a limited network bandwidth, the continuous and ...high-sampling-rate signal transmission will be prone to degradation of the LFC performance through network congestion. This brief proposes a decentralized control performance standards (CPSs)-oriented event-triggered (ET) LFC scheme for power systems under constrained communication bandwidth. The proposed scheme comprises the ET LFC scheme and the CPSs-oriented regulation scheme. In the CPSs-oriented regulation scheme, regulation rules are designed to adjust the threshold parameter of the ET LFC scheme based on the North American Electrical Reliability Council (NERC)'s CPS1 and CPS2. The rules generate a larger threshold parameter to lower the triggering frequency in order to reduce unnecessary transmission of measurement/control signals, while ensuring the frequency and tie-lie power of the power systems to meet the required CPS1 and CPS2 instead of the asymptotic stability requirement in the existing research. The reduced transmission of these signals lessens the communication burden. In addition, the decentralized control strategy is used to solve the problems of poor large scalability and computational dimension caused by the centralized control strategy. The effectiveness of the proposed scheme is evaluated on an IEEE 39-bus test system with renewable energy sources.
Load frequency control (LFC) of modern power systems tends to employ open communication networks to transmit measurement/control signals, which makes the LFC scheme more vulnerable to random time ...delays and time-delay attacks (TDAs). In this article, a resilient and active time-delay-compensation-based LFC scheme is proposed to compensate the random time delays and TDAs. At first, a state observer is employed to estimate the state of the LFC system. Then, a networked predictive control method is used to predict the control signals of the system in future moments. Next, an evaluation and compensation scheme for random time delays and TDAs is constructed in the actuator side of the LFC scheme based on the updating period of the actuator and the timestamp technique. Due to the stochastic characteristics of the random time delays or TDAs, the stability condition of the proposed scheme is developed with the aid of the mean-square stability theory. Moreover, a dual-loop open communication is employed in the proposed scheme to improve the reliability and resilience. At last, simulation and experiment tests are undertaken to demonstrate the effectiveness of the proposed scheme.
Pancreatic cancer (PC) represents a relatively rare but severe malignancy worldwide. Accumulated studies have emphasized the potential of long noncoding RNA (lncRNA) as therapeutic strategies for ...several human cancers. Thus, we aimed to investigate whether a novel non-coding RNA regulatory circuitry involved in PC. Aberrantly expressed lncRNAs and mRNAs were screened out of microarray database. Following the determination of RNA expression, PANC-1 and BxPC-3 PC cells were adopted, after which the expression of miR-330-5p, PAX8 and LINC00958 were subsequently altered. RNA crosstalk was validated by dual-luciferase reporter gene assay. In order to detect whether LINC00958 could act as ceRNA to competitively sponge miR-330-5p and regulate PAX8, subcellular location of LINC00958 and interaction between LINC00958 and miR-330-5p were measured by FISH and RNA pull down respectively. The epithelial mesenchymal transition (EMT) process, cell invasion, and tumor growth were determined in vitro and in vivo. LINC00958 and PAX8 were up-regulated, while miR-330-5p was down-regulated during PC. LINC00958 mainly expressed in the cytoplasm and LINC00958 competitively sponged miR-330-5p. Upregulated miR-330-5p or downregulated PAX8 inhibited the EMT process as well as the invasion and metastasis ability of the PC cells. Moreover, the results indicated that miR-330-5p negatively targeted PAX8, and LINC00958 ultimately showcasing its ability to bind to miR-330-5p through its interaction with AGO2. Therefore, silencing of LINC00958 may bind to miR-330-5p to inhibit PAX8 in a competitive fashion, thereby preventing the progression of PC.
•This study explores the effects of LINC00958 on PC via the miR-330-5p/PAX8 axis.•LINC00958 and PAX8 are highly expressed, yet miR-330-5p down-regulated in PC cells.•PAX8 is a target gene of miR-330-5p.•LINC00958 promotes PAX8 by binding with miR-330-5p in PC.•Down-regulated LINC00958 inhibits EMT, invasion, and metastasis of PC cells.
Uncertain transmission delays, sampling periods, parameters uncertainties regarding the power system, load fluctuations, and the intermittent generation of renewable energy sources (RESs) will ...significantly influence a power system's frequency. This article designs a robust delay-dependent PI-based load frequency control (LFC) scheme for a power system based on sampled-data control. First, a sampled-data-based delay-dependent LFC model of power system is constructed. Then, by applying the Lyapunov theory, and the linear matrix inequality technique, a novel stability criterion is developed for the LFC of the power system by considering the sampling period, and transmission delay of the communication network, which ensures that the proposed scheme operates in large sampling periods, and under transmission delays. Next, an exponential decay rate (EDR) is introduced to guide the design of a robust PI-based LFC scheme. The LFC scheme with robustness is designed by setting a small EDR. The values of EDR are adjusted by the given robust performance evaluation conditions of parameter uncertainties, and <inline-formula><tex-math notation="LaTeX">H_\infty</tex-math></inline-formula> performance. Finally, case studies are carried out based on a one-area power system, and a three-area power system with RESs. Simulation results show that the proposed LFC scheme performs strong robustness against parameter uncertainties regarding the power system, and communication network, load fluctuations, and the intermittent generation of RESs.
Simultaneous implementation of photodetector and neuromorphic vision sensor (NVS) on a single device faces a great challenge, due to the inherent speed discrepancy in their photoresponse ...characteristics. In this work, a trench‐bridged GaN/Ga2O3/GaN back‐to‐back double heterojunction array device is fabricated to enable the advanced functionalities of both devices on a single device. Interestingly, the device shows fast photoresponse and persistent photoconductivity behavior at low and high voltages, respectively, through the modulation of oxygen vacancy ionization and de‐ionization processes in Ga2O3. Consequently, the role of the optoelectronic device can be altered between the photodetector and NVS by simply adjusting the magnitude of bias voltage. As a photodetector, the device is able to realize fast optical imaging and optical communication functions. On the other hand, the device exhibits outstanding image sensing, image memory, and neuromorphic visual pre‐processing as an NVS. The utilization of NVS for image pre‐processing leads to a noticeable enhancement in both recognition accuracy and efficiency. The results presented in this work not only offer a new avenue to obtain complex functionality on a single optoelectronic device but also provide opportunities to implement advanced robotic vision systems and neuromorphic computing.
Trench‐bridged GaN/Ga2O3/GaN device is fabricated. According to the manipulation of the ionization and de‐ionization processe of oxygen vacancies within the Ga2O3, the device shows fast photoresponse at low voltages and persistent photoconductivity behavior at high voltages. Accordingly, various functions of the photodetector and neuromorphic vision sensor are achieved by one device and switched via bias voltage regulation.
Geothermal environments, such as hot springs and hydrothermal vents, are hotspots for carbon cycling and contain many poorly described microbial taxa. Here, we reconstructed 15 archaeal ...metagenome-assembled genomes (MAGs) from terrestrial hot spring sediments in China and deep-sea hydrothermal vent sediments in Guaymas Basin, Gulf of California. Phylogenetic analyses of these MAGs indicate that they form a distinct group within the TACK superphylum, and thus we propose their classification as a new phylum, 'Brockarchaeota', named after Thomas Brock for his seminal research in hot springs. Based on the MAG sequence information, we infer that some Brockarchaeota are uniquely capable of mediating non-methanogenic anaerobic methylotrophy, via the tetrahydrofolate methyl branch of the Wood-Ljungdahl pathway and reductive glycine pathway. The hydrothermal vent genotypes appear to be obligate fermenters of plant-derived polysaccharides that rely mostly on substrate-level phosphorylation, as they seem to lack most respiratory complexes. In contrast, hot spring lineages have alternate pathways to increase their ATP yield, including anaerobic methylotrophy of methanol and trimethylamine, and potentially use geothermally derived mercury, arsenic, or hydrogen. Their broad distribution and their apparent anaerobic metabolic versatility indicate that Brockarchaeota may occupy previously overlooked roles in anaerobic carbon cycling.
Mining activities exert a far-reaching impact on the quality of groundwater, and health problems caused by heavy metal pollution have attracted global attention. In this study, inductively coupled ...plasma-mass spectrometry (ICP-MS) was employed to determine the contents of 8 heavy metals (Cd, Cr, As, Fe, Mn, Cu, Zn, and Pb) in shallow groundwater samples retrieved from a mining area in northern Anhui. Multivariate statistical methods were adopted to analyze the distribution and source of pollution and to evaluate 5% and 95% health risks based on Monte Carlo simulation. Fe, As and Cr significantly exceeded the safe drinking water standards of the World Health Organization (WHO). The average concentrations of As and Cr were as high as 46.45 μg/L and 133.96 μg/L, respectively. The correlation analysis and principal component analysis (PCA) results revealed that heavy metals are affected by complex factors, the main factor being human activities. The total carcinogenic health risks of Cr and As in adults were 2.49 × 10−3 and 3.43 × 10−4, respectively, which exceeded the maximum acceptable risk value (1 ×10−4) recommended by the United States Environmental Protection Agency (USEPA), affecting human health. According to the USEPA classification of hazardous ingestion (HI), at HI < 1, the impact of non-carcinogenic heavy metals on human health is negligible. These results indicate that local residents should strengthen the monitoring of Cr and As pollution in shallow groundwater.
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•Cluster mining activities have led to an increase in the content of heavy metals in shallow groundwater.•Compound mining activities produce multiple pollution.•Monte Carlo simulation can analyze the uncertainty of the health risk value.•The greater the Monte Carlo output value, the greater the impact on the risk value.
lCUMS could induce depression-like behaviors in rats.lmiRNA sequencing analysis showed 57 differential expressed miRNAs in CUMS rats.lThese miRNAs have potential links with MAPK, Wnt, and mTOR ...pathway.
Increasing evidence has shown the important role of exosomes in the maintenance of brain function and pathogenesis of brain disease, but little is known about their association with depression. The aim of this project was to explore the miRNA profile of exosomes in the serum of rats with depression induced by chronic unpredictable mild stress (CUMS).
A rat model of depression was replicated via CUMS. Behavioral performance was observed, and serum exosomes were isolated and identified. The protein expression levels of brain-derived neurotrophic factor (BDNF), TrkB, and synaptotagmin 1 in the hippocampus, prefrontal cortex (PFC), and serum exosomes were measured. GO and KEGG enrichment analysis of differential genes was carried out using the R package clusterProfiler.
The CUMS rats showed depression-like behaviors, together with decreased expression levels of BDNF, TrkB, and synaptotagmin 1 in the hippocampus, PFC, and serum exosomes. GO and KEGG enrichment analysis indicated that the differential expression of miRNAs might play an important role in the pathogenesis of stress-induced depression through the MAPK pathway, Wnt pathway, and mTOR pathway.
The protein expression levels of BDNF, TrkB, and synaptotagmin 1 were measured only in the hippocampus and PFC. The function of the differentially expressed miRNAs was not verified in the animal model, which should be investigated in detail in future studies.
The miRNA profile was altered in rats with stress-induced depression, which might be considered a potential biomarker for the early diagnosis of depression.
The separation of micro and nanoscale colloids is a necessary step in most biological microassay techniques, and is a common practice in microchemical processing. Chemical waves are frequently ...encountered in biochemical systems driven far from equilibrium. Here, we put forward a strategy for separating small suspending colloids by means of their surfing on substrate chemical wavefronts. The colloids with catalytic activities sensitive to the substrates are activated to show self-propulsion and consequently exhibit a chemotactic response to the traveling wavefronts, which results in their spontaneous separation from the multicomponent complex mixture via self-diffusiophoresis. The dynamics of the process is analyzed through a particle-based simulation. In addition, it is found that separation can be carried out according to particle size. The mechanisms underpinning the chemical and physical separation processes are discussed, and the dependencies on the reaction rate constant and particle size are presented. The results may prove relevant for further experimental and theoretical studies of separation in complex active environments.
The dynamics of chemically powered sphere dimers at the micro- and nano-scales confined in a quasi-two-dimensional geometry are investigated. The dimer consists of a Janus particle and a ...non-catalytic sphere. A chemical reaction taking place on the catalytic surface of the Janus particle creates asymmetric concentration gradients that give rise to the self-propulsion of both rotation and translation of the dimer. Due to the chemical interactions, ensembles of dimers spontaneously form anti-parallel aligned doublets that exhibit the same rotation direction and lose translational motion. The chirality of the dimer plays an important role in the process of doublet formation. The study displays new collective dynamics and structures when both translational and rotational self-propulsion occur.
The dynamics of chemically powered sphere dimers at the micro- and nano-scales confined in a quasi-two-dimensional geometry are investigated.
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