Primary Regulator Research Articles

Acute elevated dietary fat alone is not sufficient to decrease AgRP projections in the paraventricular nucleus of the hypothalamus in mice

Within the brain, the connections between neurons are constantly changing in response to environmental stimuli. A prime environmental regulator of neuronal activity is diet, and previous work has highlighted changes in hypothalamic connections in response to diets high in dietary fat and elevated sucrose. We sought to determine if the change in hypothalamic neuronal connections was driven primarily by an elevation in dietary fat alone. Analysis was performed in both male and female animals. We measured Agouti-related peptide (AgRP) neuropeptide and Synaptophysin markers in the paraventricular nucleus of the hypothalamus (PVH) in response to an acute 48 h high fat diet challenge. Using two image analysis methods described in previous studies, an effect of a high fat diet on AgRP neuronal projections in the PVH of male or female mice was not identified. These results suggest that it may not be dietary fat alone that is responsible for the previously published alterations in hypothalamic connections. Future work should focus on deciphering the role of individual macronutrients on neuroanatomical and functional changes.

GSM1 Requires Hap4 for Expression and Plays a Role in Gluconeogenesis and Utilization of Nonfermentable Carbon Sources.

Multiple transcription factors in the budding yeast Saccharomyces cerevisiae are required for the switch from fermentative growth to respiratory growth. The Hap2/3/4/5 complex is a transcriptional activator that binds to CCAAT sequence elements in the promoters of many genes involved in the tricarboxylic acid cycle and oxidative phosphorylation and activates gene expression. Adr1 and Cat8 are required to activate the expression of genes involved in the glyoxylate cycle, gluconeogenesis, and utilization of nonfermentable carbon sources. Here, we characterize the regulation and function of the zinc cluster transcription factor Gsm1 using Western blotting and lacZ reporter-gene analysis. GSM1 is subject to glucose repression, and it requires a CCAAT sequence element for Hap2/3/4/5-dependent expression under glucose-derepression conditions. Genome-wide CHIP analyses revealed many potential targets. We analyzed 29 of them and found that FBP1, LPX1, PCK1, SFC1, and YAT1 require both Gsm1 and Hap4 for optimal expression. FBP1, PCK1, SFC1, and YAT1 play important roles in gluconeogenesis and utilization of two-carbon compounds, and they are known to be regulated by Cat8. GSM1 overexpression in cat8Δ mutant cells increases the expression of these target genes and suppresses growth defects in cat8Δ mutants on lactate medium. We propose that Gsm1 and Cat8 have shared functions in gluconeogenesis and utilization of nonfermentable carbon sources and that Cat8 is the primary regulator.

Partitioning denitrification pathways in N2O emissions from re-flooded dry paddy soils

In flooded paddy fields, peak greenhouse gas nitrous oxide (N2O) emission after rewetting the dry soils is widely recognised. However, the relative contribution of biotic and abiotic factors to this emission remains uncertain. In this study, we used the isotope technique (δ18O and δ15NSP) and molecular-based microbial analysis in an anoxic incubation experiment to evaluate the contributions of bacterial, fungal, and chemical denitrification to N2O emissions. We collected eight representative paddy soils across southern China for an incubation experiment. Results show that during the 10-day incubation period, the net N2O emissions were mainly produced by fungal denitrification, which accounted for 58–77% in six of the eight investigated flooded paddy soils. In contrast, bacterial denitrification contributed 6–15% of the net N2O emissions. Moreover, around 11–35% of the total N2O emissions were derived from chemical denitrification in all soil types. Variation partitioning analysis (VPA) and principal component analysis (PCA) demonstrated that initial soil organic carbon (OC) concentrations were the primary regulator of N2O source patterns. Soils with relatively lower OC concentration (7–15 mg g−1) tend to be dominated by fungal denitrification, which accounted for the net N2O production at the end of the incubation period. Overall, these findings highlight the dominance of the fungal denitrification pathway for N2O production in flooded paddy soils, which predominates in soils with relatively lower OC content. This suggests that fungal contribution should be considered when optimizing agricultural management system timing to control N2O emissions in flooded paddy soil ecosystems, and for the relevant establishment of predictive numerical models in the future.

Team players in the pathogenesis of metabolic dysfunctions-associated steatotic liver disease: The basis of development of pharmacotherapy.

Nutrient metabolism is regulated by several factors. Social determinants of health with or without genetics are the primary regulator of metabolism, and an unhealthy lifestyle affects all modulators and mediators, leading to the adaptation and finally to the exhaustion of cellular functions. Hepatic steatosis is defined by presence of fat in more than 5% of hepatocytes. In hepatocytes, fat is stored as triglycerides in lipid droplet. Hepatic steatosis results from a combination of multiple intracellular processes. In a healthy individual nutrient metabolism is regulated at several steps. It ranges from the selection of nutrients in a grocery store to the last step of consumption of ATP as an energy or as a building block of a cell as structural component. Several hormones, peptides, and genes have been described that participate in nutrient metabolism. Several enzymes participate in each nutrient metabolism as described above from ingestion to generation of ATP. As of now several publications have revealed very intricate regulation of nutrient metabolism, where most of the regulatory factors are tied to each other bidirectionally, making it difficult to comprehend chronological sequence of events. Insulin hormone is the primary regulator of all nutrients' metabolism both in prandial and fasting states. Insulin exerts its effects directly and indirectly on enzymes involved in the three main cellular function processes; metabolic, inflammation and repair, and cell growth and regeneration. Final regulators that control the enzymatic functions through stimulation or suppression of a cell are nuclear receptors in especially farnesoid X receptor and peroxisome proliferator-activated receptor/RXR ligands, adiponectin, leptin, and adiponutrin. Insulin hormone has direct effect on these final modulators. Whereas blood glucose level, serum lipids, incretin hormones, bile acids in conjunction with microbiota are intermediary modulators which are controlled by lifestyle. The purpose of this review is to overview the key players in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) that help us understand the disease natural course, risk stratification, role of lifestyle and pharmacotherapy in each individual patient with MASLD to achieve personalized care and target the practice of precision medicine. PubMed and Google Scholar databases were used to identify publication related to metabolism of carbohydrate and fat in states of health and disease states; MASLD, cardiovascular disease and cancer. More than 1000 publications including original research and review papers were reviewed.

Evaluation and Improvement of the Flexibility of Biomass Blended Burning Units in a Virtual Power Plant

Aiming at the problems of small thermal power units and biomass mixed combustion units with small generation loads and insufficient primary frequency modulation capability, which cannot be connected to the virtual power plant, this paper adopts a variety of flexibility retrofit methods for the units and explores the peak load capability of the units. Then, multiple units are coupled, and the unit coupling scheme with better economy and environmental protection is screened using comprehensive evaluation indexes. While evaluating the peaking load space of multiple unit coupling, the units’ primary frequency regulation capability and new energy consumption capability are improved. According to the calculation results, the low-pressure cylinder zero-output retrofit has the largest peaking potential among different technical paths, in which unit #3 has 27.55 MW of peaking space. The compression heat pump decoupling retrofit has the best economy, in which the daily profit of unit #3 increases from 0.93 to 1.02 million CNY with an increase of 0.09 million CNY. After the unit has been retrofitted with steam extraction, the three units can be coupled to meet the national feed-in standards. The multiple unit coupling can accommodate up to 203.44 MW of other energy sources while meeting the standard.

Rapid profiling of transcription factor-cofactor interaction networks reveals principles of epigenetic regulation.

Transcription factor (TF)-cofactor (COF) interactions define dynamic, cell-specific networks that govern gene expression; however, these networks are understudied due to a lack of methods for high-throughput profiling of DNA-bound TF-COF complexes. Here, we describe the Cofactor Recruitment (CoRec) method for rapid profiling of cell-specific TF-COF complexes. We define a lysine acetyltransferase (KAT)-TF network in resting and stimulated T cells. We find promiscuous recruitment of KATs for many TFs and that 35% of KAT-TF interactions are condition specific. KAT-TF interactions identify NF-κBas a primary regulator of acutely induced histone 3 lysine 27 acetylation (H3K27ac). Finally, we find that heterotypic clustering of CBP/P300-recruiting TFs is a strong predictor of total promoter H3K27ac. Our data support clustering of TF sites that broadly recruit KATs as a mechanism for widespread co-occurring histone acetylation marks. CoRec can be readily applied to different cell systems and provides a powerful approach to define TF-COF networks impacting chromatin state and gene regulation.

Acetylation of SAMHD1 at lysine 580 is crucial for blocking HIV-1 infection.

In humans, sterile alpha motif (SAM) domain- and histidine-aspartic acid (HD) domain-containing protein 1 (SAMHD1) is a dNTPase enzyme that prevents HIV-1 infection in non-cycling cells, such as differentiated THP-1 cells and human primary macrophages. Although phosphorylation of threonine 592 (T592) in SAMHD1 is recognized as the primary regulator of the ability to prevent HIV-1 infection, the contributions of SAMHD1 acetylation to this ability remain unknown. Mass spectrometry analysis of SAMHD1 proteins derived from cycling and non-cycling THP-1 cells, primary cycling B cells, and primary macrophages revealed that SAMHD1 is preferentially acetylated at lysine residues 354, 494, and 580 (K354, K494, and K580). In non-cycling cells, SAMHD1 is preferentially acetylated at K580, suggesting that this post-translational modification may contribute to the ability of SAMHD1 to block HIV-1 infection. Consistent with this finding, we found that mutations in K580 disrupted the ability of SAMHD1 to block HIV-1 infection without affecting the ability of SAMHD1 to deplete cellular dNTP levels. Gene editing of SAMHD1 in macrophage-like cells revealed that an intact K580 is required for HIV-1 restriction. This finding suggests that K580 acetylation in SAMHD1 is essential for blocking HIV-1 infection. More importantly, we found that a larger proportion of SAMHD1 featuring K580 acetylation could be detected in human primary macrophages when compared to human primary monocytes. In agreement, we found that SAMHD1 is acetylated during the monocyte-to-macrophage differentiation process. This finding agrees with the idea that the blockade of HIV-1 infection in macrophages requires SAMHD1 acetylation.IMPORTANCEThe natural inhibitor of HIV-1, sterile alpha motif (SAM) domain- and histidine-aspartic acid (HD) domain-containing protein 1 (SAMHD1), plays a pivotal role in preventing HIV-1 infection of macrophages and dendritic cells, which are vital components of the immune system. This study unveils that SAMHD1 undergoes post-translational modifications, specifically acetylation at lysines 354, 494, and 580. Our research underscores the significance of these modifications, demonstrating that acetylation at residue K580 is indispensable for SAMHD1's efficacy in blocking HIV-1 infection. Notably, K580 is found in a critical regulatory domain of SAMHD1, highlighting acetylation as a novel layer of SAMHD1 regulation for HIV-1 restriction in humans. A comprehensive understanding of the regulation mechanisms governing this anti-HIV-1 protein is crucial for leveraging nature's defense mechanisms against HIV-1 and could pave the way for innovative therapeutic strategies.

MDM2 Is Essential to Maintain the Homeostasis of Epithelial Cells by Targeting p53.

MDM2 is known as the primary negative regulator of p53, and MDM2 promotes lung cancer fibrosis and lung injury through p53-dependent and p53-independent pathways. However, the mechanism by which MDM2 influences the pathogenesis of asthma is unknown. In this study, we investigated the function of MDM2 in lung epithelial cells in type 2 lung inflammation. We used type II alveolar epithelial cell-specific heterozygous knockout of Mdm2 mice to validate its function. Then papain-induced asthma model was established, and changes in inflammation were observed by measuring immunohistochemistry and flow cytometry analysis. In this study, we knockdown the mouse Mdm2 gene in type 2 alveolar epithelial cells. We demonstrated that heterozygous Mdm2 gene-deleted mice were highly susceptible to protease allergen papain-induced pulmonary inflammation characterized by increased ILC2 numbers, IL-5 and IL-13 cytokine levels, and lung pathology. A mechanistic study showed that following the decreased expression of Mdm2 in lung epithelial cells and A549 cell line, p53 was overactivated, and the expression of its downstream genes p21, Puma, and Noxa was elevated, which resulted in apoptosis. After Mdm2 knockdown, the mRNA expression of inflammation-related gene IL-25, HMGB1, and TNF-α were increased, which further amplified the downstream ILC2 response and lung inflammation. These results indicate that Mdm2 maintains the homeostasis of lung epithelial cells by targeting P53 and regulates the function of lung epithelial cells under type 2 lung inflammation.

Dry season assessment of carbon storage and emission from upland and riparian soils in the Ganga River basin

Soil organic carbon (C) and nitrogen (N) are profoundly affected by changes in land use and land cover (LULC), especially by farming in riparian zones. The five LULC classes were selected in contiguous order, i.e., undisturbed forest (CALref), conventional agriculture lands (CAL), reservoir riparian zones (RSRZ), river riparian zones (RRZ), and undisturbed riparian zones (RZref) in the Ganga River basin to study the C storage and emission trends at a landscape scale. The riparian soils showed higher moisture, temperature, and bulk density than the upland soils, strongly determining the spatial variations in the CO2 equivalent (CO2e), C:N ratio, and CO2 efflux. Riparian CO2e was more bulk density-dependent, while upland CO2e showed greater dependence on TOC. The C:N ratio showed a higher mean value in the reference soils (CALref and RZref) than in the other soils (P < 0.05). The total nitrogen (TN), total protein (TP), and NH4-N (ammonium‑nitrogen) showed the following trend: RSRZ > CAL > RRZ > RZref > CALref. The stepwise multiple regression models illustrated that soil moisture was the primary regulator of the C:N ratio and CO2 efflux in the upland soils while the temperature in the riparian soils. These intrinsic soil variables resulted in 1.15 to 2.26 times higher CO2 efflux from the cultivated soils (CAL, RSRZ, and RRZ) than from the reference soils. Hence, the present study revealed how agricultural practices tangibly increase the riparian system's carbon footprint while offering unsustainable livelihood options to farmers.

Response Characteristics and Community Assembly Mechanisms of nirS-Type Denitrifiers in the Alpine Wetland under Simulated Precipitation Conditions.

The nitrogen cycling process in alpine wetlands is profoundly affected by precipitation changes, yet the dynamic response mechanism of denitrifiers to long-term precipitation shifts in the alpine wetland of the Qinghai-Tibet Plateau remains enigmatic. Utilizing high-throughput sequencing analysis of nirS-type functional genes, this study delved into the dynamic response mechanism of nirS-type denitrifiers to precipitation changes in the alpine wetland of Qinghai Lake. The findings revealed that nirS-type denitrifiers in the alpine wetland of Qinghai Lake were primarily Proteobacteria, and Alpha diversity exhibited a negative correlation with the precipitation gradient, with deterministic processes predominating in the community assembly of denitrifying microbes. A 50% increase in rainfall shifted the community assembly process of denitrifiers from deterministic to stochastic. Dominant microflora at the genus level responded significantly to precipitation changes, with aerobic bacteria comprising the majority of differentially abundant taxa (55.56%). As precipitation increased, the complexity of the microbial interaction network decreased, and a 25% reduction in precipitation notably elevated the relative abundance of three key functional groups: chemoheterotrophic, aerobic chemoheterotrophic, and nitrogen fixation. Precipitation notably emerged as the primary regulator of nirS-type denitrifiers in the alpine wetland of Qinghai Lake, accounting for 51% of the variation in community composition. In summary, this study offers a fresh perspective for investigating the ecological processes of nitrogen cycling in alpine ecosystems by examining the diversity and community composition of nirS-type denitrifiers in response to precipitation changes.

Molecular docking of sterol derivatives in Tagetes erecta Linn. as an antiatherosclerotic agents through activation of PPARγ and LXRα receptors

Atherosclerosis is a condition characterized by inflammation in the arteries, which is linked with the accumulation of lipids and alterations in metabolism. Considering that atherosclerosis is the main factor causing death in the world, it is necessary to carry out immediate prevention and treatment to reduce the risk of developing clinical severity. The creation of foam cells, which originate from macrophages, is considered a key element in cardiovascular ailments, particularly in the advancement of atherosclerosis. Two types of the nuclear receptors known as Peroxisome proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα), which serve as a primary regulator of cholesterol, intracellular lipid homeostasis and they are instrumental in the process of reverse cholesterol transport (RCT). Activation of these receptors could potentially decrease foam cell formation, consequently lowering the risk of atherogenesis and reducing cardiovascular disease risk. This research aims to determine sterol derivative compounds in Tagetes erecta Linn. which have the best interaction and potential as anti-atherosclerosis through peroxisome proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) activation. The analysis of this study is using docking molecular analysis. The parameters observed in this study were docking score, visualization results, absorption, distribution, metabolism, excretion profile, and toxicity value. The molecular docking outcomes indicate that β-sitosterol and 7β-hydroxysitosterol possess the most favorable binding energy values. They exhibit a positive pharmacokinetic profile, with the exception of gastrointestinal absorption and respiratory toxicity.

Gut Microbiota Defines Functional Direction of Colonic Regulatory T Cells with Unique TCR Repertoires.

Intestinal microbiota and selected strains of commensal bacteria influence regulatory T (Treg) cell functionality in the colon. Nevertheless, whether and how microbiota changes the transcriptome profile and TCR specificities of colonic Tregs remain to be precisely defined. In this study, we have employed single-cell RNA sequencing and comparatively analyzed colonic Tregs from specific pathogen-free and germ-free (GF) mice. We found that microbiota shifts the activation trajectory of colonic Tregs toward a distinct phenotypic subset enriched in specific pathogen-free but not in GF mice. Moreover, microbiota induced the expansion of specific Treg clonotypes with shared transcriptional specificities. The microbiota-induced subset of colonic Tregs, identified as PD-1- CXCR3+ Tregs, displayed enhanced suppressive capabilities compared with colonic Tregs derived from GF mice, enhanced production of IL-10, and were the primary regulators of enteric inflammation in dextran sodium sulfate-induced colitis. These findings identify a hitherto unknown gut microbiota and immune cell interaction module that could contribute to the development of a therapeutic modality for intestinal inflammatory diseases.

Exploring the Utility of Long Non-Coding RNAs for Assessing the Health Consequences of Vaping.

Electronic cigarette (e-cig) use, otherwise known as "vaping", is widespread among adolescent never-smokers and adult smokers seeking a less-harmful alternative to combustible tobacco products. To date, however, the long-term health consequences of vaping are largely unknown. Many toxicants and carcinogens present in e-cig vapor and tobacco smoke exert their biological effects through epigenetic changes that can cause dysregulation of disease-related genes. Long non-coding RNAs (lncRNAs) have emerged as prime regulators of gene expression in health and disease states. A large body of research has shown that lncRNAs regulate genes involved in the pathogenesis of smoking-associated diseases; however, the utility of lncRNAs for assessing the disease-causing potential of vaping remains to be fully determined. A limited but growing number of studies has shown that lncRNAs mediate dysregulation of disease-related genes in cells and tissues of vapers as well as cells treated in vitro with e-cig aerosol extract. This review article provides an overview of the evolution of e-cig technology, trends in use, and controversies on the safety, efficacy, and health risks or potential benefits of vaping relative to smoking. While highlighting the importance of lncRNAs in cell biology and disease, it summarizes the current and ongoing research on the modulatory effects of lncRNAs on gene regulation and disease pathogenesis in e-cig users and in vitro experimental settings. The gaps in knowledge are identified, priorities for future research are highlighted, and the importance of empirical data for tobacco products regulation and public health is underscored.

Consumer Theory-Based Primary Frequency Regulation in Multi-Microgrid Systems within a P2P Energy Management Framework

This paper presents a novel primary frequency regulation strategy for multi-microgrid (MMG) systems, utilizing consumer theory within a peer-to-peer (P2P) energy management framework. By coordinating photovoltaic (PV) systems and energy storage systems (ESS), the proposed method ensures a rapid and effective response to frequency deviations. Unlike conventional approaches, this strategy minimizes the curtailment of renewable energy sources by prioritizing the use of ESS, allowing excess energy to charge the ESS for later use during under-frequency events. This not only enhances energy efficiency but also maximizes renewable energy utilization. Simulations demonstrate that the proposed scheme achieves lower frequency deviations and faster stabilization compared to traditional droop and virtual inertia methods. These results highlight the potential benefits of integrating consumer theory-based models into primary frequency regulation, significantly enhancing system stability and efficiency in power systems with high levels of renewable energy penetration.

Exploring SALL4 as a significant prognostic marker in breast cancer and its association with progression pathways involved in cancer genesis

Breast carcinoma is the leading factor in women's cancer-related fatalities. Due to its numerous inherent molecular subtypes, breast cancer is an extremely diverse illness. The human epidermal growth factor receptor 2 (HER2) positive subtypes stands out among these subtypes as being especially prone to cancer development and illness recurrence. The regulation of embryonic stem cells' pluripotency and self-renewal is carried out by the SALL4 (Spalt-like transcription factor 4) family member. Numerous molecular pathways operating at the transcriptional, post-transcriptional, and epigenomic levels regulate the expression of SALL4. Many transcription factors control the expression of SALL4, with STAT3 being the primary regulator in hepatocellular carcinoma (HCC) and breast carcinoma. Moreover, this oncogene has been connected to a number of cellular functions, including invasion, apoptosis, proliferation, and resistance to therapy. Reduced patient survival rates and a worse prognosis have been linked to higher levels of SALL4. In order to target the undruggable SALL4 that is overexpressed in breast carcinoma, we investigated the prognostic levels of SALL4 in breast carcinoma and its interaction with various related proteins. Using TIMER 2.0 analysis, the expression pattern of SALL4 was investigated across all TCGA datasets. The research revealed that SALL4 expression was elevated in various cancers. The UALCAN findings demonstrated that SALL4 was overexpressed in all tumor samples including breast cancer especially TNBC (Triple negative breast cancer). The web-based ENRICHR program was used for gene ontology analysis that revealed SALL4 was actively involved in the development of the nervous system, positive regulation of stem cell proliferation, regulation of stem cell proliferation, regulation of the activin receptor signaling pathway, regulation of transcription using DNA templates, miRNA metabolic processes, and regulation of transcription by RNA Polymerase I. Using the STRING database, we analyzed the interaction and involvement of SALL4 with other abruptly activated proteins and used Cytoscape 3.8.0 for visualization. Additionally, using bc-GenExMiner, we studied the impact of SALL4 on pathways abruptly activated in different breast cancer subtypes that revealed SALL4 was highly correlated with WNT2B, NOTCH4, AKT3, and PIK3CA. Furthermore, to target SALL4, we evaluated and analyzed the impact of CLP and its analogues, revealing promising outcomes.

The invertase gene PWIN1 confers chilling tolerance of rice at the booting stage via mediating pollen development.

Pollen fertility is a primary regulator of grain yield and is highly susceptible to cold and other environmental stress. We revealed the roles of rice cell wall invertase gene PWIN1 in pollen development and chilling tolerance. We uncovered its preferential expression in microspores and bicellular pollen and identified its knock-down and knock-out mutants. pwin1 mutants produced a higher proportion of abnormal pollen than wild-type plants. The contents of sucrose, glucose, and fructose were increased, while ATP content and primary metabolism activity were reduced in the mutant pollen. Furthermore, the loss of function of PWIN1 coincided with an increase in SnRK1 activity and a decrease in TOR activity. Under chilling conditions, pwin1 mutants displayed significantly reduced pollen viability and seed-setting rate, while overexpressing PWIN1 notably increased pollen viability and seed-setting rate as compared with the wild-type, indicating that PWIN1 is essential for rice pollen development and grain yield under cold stress. This study provides insights into the molecular mechanisms underlying rice pollen fertility during chilling stress, and a new module to improve chilling tolerance of rice at the booting stage by molecular design.

Application of Grid Forming Control in Energy Storage Systems for Primary Frequency Regulation Case Study: Galapagos Islands

Application of Grid Forming Control in Energy Storage Systems for Primary Frequency Regulation Case Study: Galapagos Islands

An optimizated additional damping control for suppressing ultra‐low frequency oscillation suppression based on SVC

AbstractThe ultra‐low frequency oscillation (ULFO) imposes an emerging stability challenge to the high proportion of hydropower grids. To suppress ULFO without reducing the primary frequency regulation of the hydro governor, a novel idea to exploit the voltage regulation effect of load is implemented. First, the additional damping controller is designed and configured in static var compensator (SVC), and the frequency analysis model considering the configuration of SVC as well as damping controller is established. Based on the model, the specific influence of SVC and controller on ULFO is analysed through eigenvalue calculation. In addition, the influence of various load models and SVC location on the damping level are further studied. Consequently, a parameter optimization design method for SVC additional damping control is proposed, it is modelled as the optimization problem of damping ratio in ULFO mode under multi‐operation conditions, which is solved by a particle swarm optimization algorithm. Finally, the effectiveness of the designed SVC additional damping controller is verified in the improved four‐machine two‐area power system and the actual power grid in China.

Joint Scheduling Method for Pumped Storage Units and Renewable Energy Sources

With the integration of renewable energy sources, how we can improve the stability of the new energy power system has become an urgent issue pursued by scholars. In this paper, a joint scheduling method for pumped storage units (PSUs) and renewable energy sources (RESs) considering frequency deviation and voltage stiffness constraints is proposed. First, the analytical expression of the frequency deviation constraint is derived based on the primary frequency regulation model. Then, the voltage stiffness constraint is constructed to describe the system’s capability of maintaining the voltage magnitude. Finally, to minimize the renewable energy abandonment caused by stability requirements, the joint scheduling model for PSUs and RESs is established. The application of the method ensures that the frequency deviation of the modified IEEE 39 bus system is less than 0.5 Hz, while the voltage stiffness remains above 0.9.

Wireless Power Transfer System with Constant Voltage/Constant Current Output Performance

Aiming at the problem of unstable output voltage and output current caused by load fluctuation, this paper starts from the perspective of system topology and control strategy for analysis. First, the output characteristics of LCL-S (inductor-capacitor-inductor and series), LCL-P (inductor-capacitor-inductor and parallel), LCL-LCL (inductor-capacitor-inductor and inductor-capacitor-inductor), and LCL-LCC (inductor-capacitor-inductor and inductor-capacitor-capacitor) compensation topologies are analyzed. Combining the advantages of LCL-S and LCL-LCL compensation topology output characteristics, an LCL-LCL/S compensation topology is constructed, and its topology is optimized. Then the influence of parasitic resistance on the output characteristics of LCL-LCL/S compensation topology is derived. A control strategy of primary side regulation is proposed to address the issue of unstable output voltage and current caused by parasitic resistance in the system under variable loads. This method can effectively improve the stability of the output voltage and output current of the wireless power transfer system in the LCL-LCL/S compensation topology under load fluctuations. Finally, a set of experimental prototypes is built to verify the correctness of the theoretical analysis.