Compensation Capacity Research Articles

A multifunctional inverter power quality coordinated optimization strategy based on comprehensive evaluation

The large-scale integration of renewable energy sources and power electronic devices has led to increasingly dispersed and networked characteristics of power quality disturbances in distribution systems. Traditional control devices, limited by their fixed-point control, no longer meet the development needs of modern distribution systems. Considering the distribution and structural characteristics of the current new-type sources and loads, a multifunctional inverter power quality coordinated control strategy based on comprehensive evaluation is proposed. This strategy aims to achieve power quality coordinated control by utilizing optimal compensation capacity while the grid-connected inverter provides active power output. Firstly, the traditional ipiq power quality detection method is analyzed and improved to enable detection of harmonics, reactive power, and three-phase imbalance currents in single-phase systems or three-phase four-wire systems. Secondly, in the power quality assessment, a balanced algorithm is employed to obtain the comprehensive evaluation index of power quality, thereby improving the deficiencies of single-weight evaluation. Next, to ensure the grid-connected inverter achieves optimal power quality coordinated control with minimal compensation capacity, an optimization compensation function is established between compensation capacity and comprehensive power quality index. This function is optimized using non-dominated sorting genetic algorithm to enhance equipment utilization and system economy. Finally, the feasibility and effectiveness of the proposed method are validated through simulations, demonstrating the achievement of optimal capacity configuration for power quality coordinated control while ensuring active power output by the grid-connected inverter.

Konsep Dasar dan Ruang Lingkup Manajemen Pendidik Dan Tenaga Kependidikan

The aim of this research is to integrate Islamic management principles in the management of educators and education personnel in order to improve the quality and effectiveness of education. This research uses the library research method to explore and analyze literature from various written sources such as books, journals, articles, dissertations and official documents regarding the management of educators and education personnel, with the aim of understanding existing theories and identifying gaps in the literature. Data was collected through literature searches in academic databases, selection of credible sources, organizing data based on themes, and analysis by reducing, presenting, and synthesizing information to draw conclusions that can improve the quality and effectiveness of educational management. The result of this work is that educators, including teachers, lecturers and counselors, have an important role in the educational process with the main task of teaching, educating and guiding students, while educational staff such as tutors and instructors support the implementation of education through technical tasks. The management of educators and education personnel is based on Islamic teachings which emphasize skill, discipline and good implementation of tasks, as well as the principle of order to achieve organizational goals. The aim of this management is to ensure that the institution has a quality workforce, an effective work system and a harmonious work climate through recruitment, fair compensation and employee capacity development. Management covers critical aspects such as curriculum, personnel, classes, student affairs, and finance, with duties and functions that emphasize professionalism to improve the quality of education. Even though it is formally recognized, Islamic educational institutions in Indonesia still face quality challenges due to limited facilities and the government's unpreparedness.

Study on fast transient overvoltage characteristics of substation under UHV disconnector operation

Abstract Due to the short duration of fast transient overvoltage in the substation, the suppression effect under the control strategy of traditional optimization equipment and switches is not good. Therefore, the characteristics of fast transient overvoltage in substation under the operation of a UHV disconnector are proposed. The fast transient condition of the substation is analyzed, the corresponding simulation method is set, and it is simulated. The elimination operation is carried out by using the reverse sequence backtracking formula, and the relevant parameters of the fast transient condition simulation of the substation are obtained. The inductance of the substation is calculated in the fast transient process, the potential in the equivalent circuit is obtained by using the capacitance and inductance, and the reactive power compensation capacity on the electromagnetic transient model of the fast transient process is comprehensively considered, so as to calculate the rapid transient overvoltage of the substation and realize the research on overvoltage characteristics. The method in this paper can ensure the rapid transient overvoltage level decline, successfully realize the automatic voltage regulation, effectively maintain the stability of voltage, and effectively restrain overvoltage to keep it within an acceptable range.

Longitudinal Assessment of Outcome Measures of Diaphragm Motor Unit Connectivity As Biomarkers of Phrenic Motor Unit Degeneration and Compensation

Phrenic motor neurons (MNs) form the final link from the central nervous system (CNS) to the diaphragm muscle. Ventilatory function is modulated by the CNS via groups of muscle fibers each controlled by a single MN (motor units). Processes such as injury, aging, and neurodegeneration can result in losses of MNs, and their motor unit (MU) counterparts, but MNs and MUs have some capacity for compensation through mechanisms such as axonal sprouting and collateral sprouting to regain connectivity with denervated muscle. Motor unit number (motor unit number estimation, MUNE), MU size (single motor unit potential amplitude, SMUP), and summated muscle excitation (compound muscle action potential amplitude, CMAP) have been used clinically and preclinically for decades to track MU connectivity but efforts have largely focused on limb muscles. We aimed to apply these measures to a model of phrenic MN degeneration (intrapleural injection of cholera toxin B fragment conjugated to saporin, CTB-SAP).We hypothesized that CTB-SAP-induced phrenic motor neuron death would result in loss of diaphragm MU number and compensatory increases in MU size. Under isoflurane anesthesia, rats were bilaterally, intrapleurally injected with CTB-SAP (25 μg) to target phrenic MNs and extra CTB (25 μg) to label surviving phrenic MNs, and control rats received unconjugated CTB (25 μg) and SAP (25 μg). Diaphragm CMAP, SMUP, and MUNE were acquired bilaterally and averaged at baseline/pre-injection (n=14), as well as 7 (n=14), 14 (n=14), 21 (n=6), and 28 (n=14) days post-injection. No baseline differences between groups were found. MUNE showed a significant change for time (p<0.05), treatment (p<0.001), and interaction time x treatment (p<0.01) with ~40% reduction of MUNE in CTB-SAP rats. Average SMUP of CTB-SAP rats demonstrated a significant change with time (p<0.05) and treatment (p<0.01), but no significant interaction with ~50-60% increase in SMUP amplitude. CMAP showed no significant change. Our results show a significant ~40% loss of MUs in CTB-SAP rats, similar to previous studies on morphological MN counts. In parallel with MU loss, MUs enlarged (increased SMUP), consistent with compensatory increases of MU size likely through MU collateral sprouting. In conclusion, our findings suggest that the use of diaphragm MU electrophysiological measures can provide insights into the onset and progression of CTB-SAP-induced pathology concerning the loss of phrenic MU integrity. Hence, these biomarkers can be used to investigate mechanisms of phrenic motor neuron degeneration and compensation, and to expedite the translation of experimental findings to clinical testing. Supported by a Spinal Cord Injury and Disease Research grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Comparing Integrative Respiratory and Renal Acid-Base Acclimatization in Lowlanders and Tibetan Highlanders During Incremental Ascent to 4,300m

During sustained exposure to high altitude, integrated respiratory and renal acclimatization protects blood oxygenation and acid-base homeostasis, respectively. A sustained and augmented hypoxic ventilatory response (HVR) protects blood oxygenation with ascent (i.e., ventilatory acclimatization). However, the HVR elicits hypocapnia and respiratory alkalosis. A subsequent renally-mediated compensatory metabolic acidosis partially returns pH back to baseline values, with a high degree of variability, and capacity for full compensation limited to approximately 4000-4500m. In convenience samples of fully-acclimatized participants, indigenous highlanders of Tibetan ancestry (TH; i.e., Sherpa) have been reported to have (a) similar ventilatory acclimatization but, (b) improved renal compensation than lowlanders (LL) at 4300m. However, little work has been performed on the differences in renal acclimatization between LL and TH during acclimatization with incremental ascent to high altitude over a similar ascent profile. We assessed renal acclimatization between acclimatizing LL and TH, and hypothesized that (a) TH would have similar ventilatory acclimatization to LL but (b) larger magnitude renal compensation than LL during incremental ascent from 1400m to 4300m. Age- and sex-matched groups of 15 unacclimatized LL (8F) and 14 unacclimatized TH of confirmed Tibetan ancestry (7F) were recruited at 1400m. Utilizing an average of two finger capillary blood draw samples and a blood gas analyzer, we compared renally-mediated acid-base acclimatization (PCO2, [HCO3−], pH) in both groups before (1400m) and following day 8-9 of incremental ascent to 4300m. We found that following ascent, LL had significantly lower PCO2 (p<0.0001) and [HCO3-] (p<0.0001), and higher pH (P=0.0037), suggesting respiratory alkalosis and only partial renal compensation. However, TH had significantly lower PCO2 (p<0.0001) and [HCO3−] (p<0.0001), but unchanged pH (P=0.1), suggesting full renal compensation. At 4300m, TH had significantly lower PCO2 (P=0.01), [HCO3−] (p<0.0001) and pH (P=0.005) than LL. These data suggest that TH have larger magnitude and more rapid time-course ventilatory and renal mechanisms compared to LL, resulting in fully-compensated pH in TH during incremental ascent to high altitude, despite a larger hypocapnic stimulus. To our knowledge, this is the first study to demonstrate these integrated respiratory-renal responses between acclimatizing LL and TH. MRU, NSERC, NSF. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Harmonic Distortion Study of a Photovoltaic Generator in a Microgrid under Disturbances

This paper describes research on the harmonic-distortion capacity of a single-stage photovoltaic (PV) 3.68 kWp generator in a microgrid configuration. An overview of various harmonic compensator methods used in PV generators is presented to evaluate their advantages and disadvantages. Proportional-resonant (PR) structures with harmonic compensators (HCs) are designed, modeled, and validated through real-time tests. The modeling of harmonic compensation structures for a photovoltaic inverter using MATLAB/SIMULINK R2022a is explained in detail. The harmonic compensation capacity of a PV generator inverter is studied under voltage harmonics, grid frequency variation, and voltage unbalance. The contributions of this work are, firstly a bibliographic analysis of various strategies currently used for harmonic compensation in grid-connected inverters and secondly, a detailed explanation of the modeling of harmonic compensation structures using MATLAB/SIMULINK. Finally, a demonstration of the improvement in energy quality that results from using harmonic compensation techniques in photovoltaic generators in microgrid configurations affected by grid disturbances is performed. The obtained results show that harmonic compensation strategies based on resonant filters are a good alternative for the reduction of harmonic voltage distortion in the presence of grid disturbances such as frequency variation and voltage unbalance.

Multivariate mapping of low-resilient neurocognitive systems within and around low-grade gliomas.

Accumulating evidence suggests that the brain exhibits a remarkable capacity for functional compensation in response to neurological damage, a resilience potential that is deeply rooted in the malleable features of its underlying anatomofunctional architecture. This propensity is particularly exemplified by diffuse low-grade glioma, a subtype of primary brain tumour. However, functional plasticity is not boundless, and surgical resections directed at structures with limited neuroplasticity can lead to incapacitating impairments. Yet, maximizing diffuse low-grade glioma resections offers substantial oncological benefits, especially when the resection extends beyond the tumour margins (i.e. supra-tumour or supratotal resection). In this context, the primary objective of this study was to identify which cerebral structures were associated with less favourable cognitive outcomes after surgery, while accounting for intra-tumour and supra-tumour features of the surgical resections. To achieve this objective, we leveraged a unique cohort of 400 patients with diffuse low-grade glioma who underwent surgery with awake cognitive mapping. Patients benefitted from a neuropsychological assessment consisting of 18 subtests administered before and 3 months after surgery. We analysed changes in performance and applied topography-focused and disconnection-focused multivariate lesion-symptom mapping using support vector regressions, in an attempt to capture resected cortico-subcortical structures less amenable to full cognitive compensation. The observed changes in performance were of a limited magnitude, suggesting an overall recovery (13 of 18 tasks recovered fully despite a mean resection extent of 92.4%). Nevertheless, lesion-symptom mapping analyses revealed that a lack of recovery in picture naming was linked to damage in the left inferior temporal gyrus and inferior longitudinal fasciculus. Likewise, for semantic fluency abilities, an association was established with damage to the left precuneus/posterior cingulate. For phonological fluency abilities, the left dorsomedial frontal cortex and the frontal aslant tract were implicated. Moreover, difficulties in spatial exploration were associated with injury to the right dorsomedial prefrontal cortex and its underlying connectivity. An exploratory analysis suggested that supra-tumour resections were associated with a less pronounced recovery following specific resection patterns, such as supra-tumour resections of the left uncinate fasciculus (picture naming), the left corticostriatal tract and the anterior corpus callosum (phonological fluency), the hippocampus and parahippocampus (episodic memory) and the right frontal-mesial areas (visuospatial exploration). Collectively, these patterns of results shed new light on both low-resilient neural systems and the prediction of cognitive recovery following glioma surgery. Furthermore, they indicate that supra-tumour resections were only occasionally less well tolerated from a cognitive viewpoint. In doing so, they have deep implications for surgical planning and rehabilitation strategies.

Legal Study of Alternative Models of Land Procurement for Public Interest Development Viewed from Human Rights Perspective

Purpose: This research addresses a prominent land-related challenge, specifically focusing on the issue of remedies during the land procurement process, which constitutes 7.65% of the overall concerns. Among the identified remedies (seven in total) applicable to land procurement for public interest development, a significant majority (87.5%) involves parties denying payment. This observation points to a noteworthy aspect: the government's neglect of human rights considerations within the land procurement process. Methods: The study uses normative juridical and empirical methods, employing prescriptive analysis to understand the legal aspects of depositing compensation for public land acquisition. It utilizes legislative analysis, case studies, and interviews to qualitatively analyze data, aiming for comprehensive insights. Results and Conclusion: The study advocates for a land procurement approach rooted in human rights principles. Such an approach encompasses the entire process, from initial planning to development, emphasizing the importance of respecting honor, dignity, and the fulfillment of rights to restore the lives of landowners. Alternative models are proposed, encouraging active involvement of relevant parties in the planning phase to comprehensively identify problems and collaboratively design future-focused solutions. Parties entitled to compensation are afforded the opportunity to contribute to determining the fair value of the land. In cases where mutual agreement cannot be reached, scheduled meetings provide a platform for entitled parties to present their grievances and obtain remedies essential for their sustenance. These remedies may include financial support for a specified duration. Consequently, parties entitled to compensation play a pivotal role in permitting the government to initiate development for the greater public interest, ensuring the fulfillment of their rights and well-being. This alternative model strives to establish a more equitable and participatory framework for land procurement, prioritizing and safeguarding the rights of all involved parties throughout the entire process. Research implications: This research has several important implications for study and practical implementation in the field of land procurement. These implications include the need for legal reforms, a human rights-based approach, stakeholder participation, alternative compensation models, capacity building, comparative studies, and monitoring and evaluation. By considering these implications, policymakers and practitioners can work towards more equitable, sustainable land acquisition practices that respect the rights of all parties involved. Originality/value: The originality and value of this research lie in its contribution to the understanding of land procurement processes and their implications for human rights and equitable development. The study offers fresh insights by identifying and analyzing the challenges and remedies encountered during land acquisition for public interest projects. The proposed alternative models and recommendations provide practical approaches to address these challenges, with a focus on stakeholder participation, fair compensation, and the integration of human rights principles. The research adds value to the existing literature by emphasizing the importance of considering human rights in land procurement and suggesting ways to improve the fairness and inclusivity of these processes. It serves as a basis for future studies and policy reforms aimed at promoting more just and sustainable land acquisition practices.

Suitability of capacitor allocation methods in different kinds of distribution networks

In the context of power systems with “a high percentage of renewable energy” and “a high percentage of power electronic equipment”, reactive power capacitors are demanded to support the voltage and keep the economic operation of the distribution network. Reasonable configuration of reactive power compensation including capacitor location and compensation capacity can keep the system voltage at a reasonable level, improve the system voltage stability, and reduce the network loss. In this paper, a reactive power optimization model based on three capacitor allocation methods, namely the reactive power sensitivity method, the active power loss method, and the voltage stability method, was established. Considering the stability and economy of distribution network operation, the suitability of the different methods in different kinds of distribution networks was evaluated in terms of the indicators of minimizing the network loss, minimizing the voltage offset, and minimizing the system operation cost. The simulation results show that the active power loss method is the most suitable for reducing voltage fluctuations and network losses.

Collaborative Control of Reactive Power and Voltage in a Coupled System Considering the Available Reactive Power Margin

This article proposes a hierarchical collaborative reactive power and voltage control method aimed at meeting the internal voltage requirements of a coupled system composed of centralized new energy stations such as wind and solar power and traditional thermal power units, with particular attention paid to the reactive power regulation ability of power units in new energy stations. This method is implemented in two layers: At the transmission layer, the overall reactive power compensation capacity of thermal power units and stations on the transmission lines within the system is determined according to the engineering requirements of different node voltages in the coupled system, the regulation voltages of the high-voltage grid-connected points and the point of common coupling (PCC) of the stations are found, and the actual regulation voltages of the PCCs of the stations are given as commands. At the station layer, based on determining reactive power distribution between power units and continuous reactive power compensation devices within each station, voltage optimization is carried out using the voltage command issued by the transmission layer as a reference. At the same time, consistency coordination between the transmission layer and the station layer is achieved based on the Analytical Target Cascading (ATC) method at different layers. Finally, simulation analysis was conducted on a regional coupled system in Dalian. The results showed that the method proposed in this paper can effectively control the voltage safety requirements of each region and PCC in the coupled system and, to some extent, improve the economic efficiency of system operation.

Grid‐side flexibility assessment based on security distance of dispatchable region for AC/DC hybrid system using approximate second‐order cone relaxation

AbstractThe rapid growth of offshore wind power has resulted in a mismatch between generation and demand because of its variability. To quantify the maximum wind power penetration of the transmission network, the dispatchable region is defined as the largest region in the uncertainty space. The security distance is defined as the minimum distance from the operating point to the boundaries of the dispatchable region. System operators can use security distance as a metric to assess the flexibility of the power system. This paper proposes a method to construct the dispatchable region for the AC/DC hybrid system with VSC‐HVDC by outer convex relaxation firstly. The second‐order cone relaxation is employed to reformulate non‐convex and non‐linear power flow equations. Next, a polyhedral approximation is adopted to obtain the convex hull of the dispatchable region. Subsequently, an efficient algorithm known as adaptive constraint generation (Ad‐CG) is introduced to calculate the boundaries of the dispatchable region. Furthermore, solving the Chebyshev centre problem determines the minimal security distance. The modified IEEE 5‐bus and 39‐bus system is used for validating effectiveness of the proposed method and evaluating the impact of the converter reactive power compensation capacity and generation dispatch on the dispatchable region.

Analytical method of determining conditions for full compensation of reactive power in the power supply system

Goal. The purpose of the article is the development of an analytical method for determining the conditions for achieving full compensation in the generalized power supply system based on the use of substitute circuits, which are obtained using equivalent transformations of the topology of the original circuit. Methodology. The article proposes a methodology for replacing series reactive power compensation in high-voltage paths of the power supply system with parallel reactive power compensation in a low-voltage load node. Results. An algorithm for successive transformations of the power supply circuit has been developed, which makes it possible to estimate the values of the capacitances of compensating capacitors, at which full compensation of reactive power in the system is achieved. Originality. The proposed analytical method for calculating the parameters of the compensation unit makes it possible to dispense with complex optimization computer methods and makes it possible to estimate the compensation capacities that fall on the share of the load and the network. Practical value. The proposed technique allows, using a simple algorithm, to determine with high accuracy the necessary parameters of the compensating device, which provide the optimal mode in the power supply system. The proposed algorithm can easily be implemented in a microcontroller system for automatic control of the modes of the power supply system.

Coordinated control strategy of reactive power compensation based on a flexible distribution network transformer

In order to solve the problem of the power quality caused by distributed power access to the distribution network, this paper proposes a coordinated control strategy of reactive power compensation based on a flexible distribution transformer. First, the working principle of the flexible distribution transformer is analyzed, and the mathematical model of energy acquisition and the regulation converter of the flexible distribution transformer are studied as well. The device-level control strategies of energy acquisition and regulation converters are proposed, respectively. Then, in order to maintain the stability of the bus voltage and quickly respond to the reactive power changes of the system, a coordinated control strategy for the reactive power compensation of flexible distribution transformers is proposed. The priority herein is to maximize the reactive power compensation capacity of the energy harvesting converter. When the energy harvesting converter reaches the compensation upper limit, the control converter is used for reactive power compensation to further suppress the grid voltage fluctuation. Finally, it is verified through simulations that the flexible distribution transformer can realize the reactive power compensation of the distribution network and effectively improve the power quality of the distribution network.

Stabilization control of rotary inverted pendulum using a novel EKF-based fuzzy adaptive sliding-mode controller: design and experimental validation

This article methodically develops an improved self-regulating fuzzy-adaptive Sliding Mode Controller (SMC) that strengthens the disturbance compensation capacity of the nonlinear rotary pendulum systems while effectively attenuating the chattering content and curbing the control energy consumption. The article contributes to augmenting the SMC with online adaptation tools to achieve the said objectives. It employs the conventional Gao’s power-rate reaching law as the baseline. The scaling gain and the power rate of the said reaching law are adaptively modulated via a pre-calibrated two-input state-error-driven fuzzy nonlinear function. Additionally, the sign function in the law is also replaced with an odd-symmetric nonlinear fuzzy function to address the hard limits imposed by the former. Finally, the membership functions of the fuzzy function are self-regulated using the Extended-Kalman-Filter to improve the compensator’s adaptability in handling the system’s rapidly changing control requirements under exogenous disturbances. The aforementioned propositions are verified by performing customized and reliable hardware-in-loop experiments on the Quanser single-link rotary pendulum platform. As compared to baseline SMC law, the proposed control procedure contributes a ∼45.2%, ∼48.5%, and ∼34.8% reduction in position-regulation errors, control energy consumption, and peak overshoots, respectively. The experimental assessment validates the proposed control system’s enhanced robustness and chattering-suppression capability.

Innovative approaches for managing patients with chronic vestibular disorders: follow-up indicators and predictive markers for studying the vestibular error signal.

Despite significant advancements in understanding the biochemical, anatomical, and functional impacts of vestibular lesions, developing standardized and effective rehabilitation strategies for patients unresponsive to conventional therapies remains a challenge. Chronic vestibular disorders, characterized by permanent or recurrent imbalances and blurred vision or oscillopsia, present significant complexity in non-pharmacological management. The complex interaction between peripheral vestibular damage and its impact on the central nervous system (CNS) raises questions about neuroplasticity and vestibular compensation capacity. Although fundamental research has examined the consequences of lesions on the vestibular system, the effect of a chronic peripheral vestibular error signal (VES) on the CNS remains underexplored. The VES refers to the discrepancy between sensory expectations and perceptions of the vestibular system has been clarified through recent engineering studies. This deeper understanding of VES is crucial not only for vestibular physiology and pathology but also for designing effective measures and methods of vestibular rehabilitation, shedding light on the importance of compensation mechanisms and sensory integration. This retrospective study, targeting patients with chronic unilateral peripheral vestibulopathy unresponsive to standard treatments, sought to exclude any interference from pre-existing conditions. Participants were evaluated before and after a integrative vestibular exploratory and rehabilitation program through questionnaires, posturographic tests, and videonystagmography. The results indicate significant improvements in postural stability and quality of life, demonstrating positive modulation of the CNS and an improvement of vestibular compensation. Successful vestibular rehabilitation likely requires a multifaceted approach that incorporates the latest insights into neuroplasticity and sensory integration, tailored to the specific needs and clinical progression of each patient. Focusing on compensating for the VES and enhancing sensory-perceptual-motor integration, this approach aims not just to tailor interventions but also to reinforce coherence among the vestibular, visual, and neurological systems, thereby improving the quality of life for individuals with chronic vestibular disorders.

Lattice Engineering on Li2CO3-Based Sacrificial Cathode Prelithiation Agent for Improving the Energy Density of Li-Ion Battery Full-Cell.

Developing sacrificial cathode prelithiation technology to compensate for active lithium loss is vital for improving the energy density of lithium-ion battery full-cells. Li2CO3 owns high theoretical specific capacity, superior air stability, but poor conductivity as an insulator, acting as a promising but challenging prelithiation agent candidate. Herein, extracting a trace amount of Co from LiCoO2 (LCO), a lattice engineering is developed through substituting Li sites with Co and inducing Li defects to obtain a composite structure consisting of (Li0.906Co0.043▫0.051)2CO2.934 and ball milled LiCoO2 (Co-Li2CO3@LCO). Notably,both the bandgap and Li─O bond strength have essentially declined in this structure. Benefiting from the synergistic effect of Li defects and bulk phase catalytic regulation of Co, the potential of Li2CO3 deep decomposition significantly decreases from typical >4.7 to ≈4.25V versus Li/Li+, presenting >600 mAh g-1 compensation capacity. Impressively, coupling 5 wt% Co-Li2CO3@LCO within NCM-811 cathode, 235Wh kg-1 pouch-type full-cell is achieved, performing 88% capacity retention after 1000 cycles.

Effect of collateral circulation in patients with multiple craniocervical artery stenoses.

Based on previous findings, collateral circulation in the brain is vital in mitigating cerebral ischemia's effects and influencing stroke risk. This retrospective study examined collateral circulation, admission ischemic stroke status, and long-term recurrence in patients with multiple craniocervical artery stenoses. Consecutive symptomatic internal carotid artery (ICA) stenosis patients from the First Affiliated Hospital of Soochow University were recruited. Baseline data including medical histories and neurological function at admission were collected. Imaging techniques assessed collateral compensative capacity. Multivariate logistic regression analysis was used to investigate the association between collateral circulation and case status. A total of 559 patients with symptomatic ICA stenosis were included, among whom 153 (27.4%) had concurrent moderate to severe vertebro-basilar artery (VBA) stenosis. Dizziness, weakness/numbness, and slurring of speech were the primary symptoms in all patients. Over 36 months, 71 (12.7%) patients experienced a recurrence of acute ischemic stroke (AIS). In multivariate analysis, collateral circulation was found to be negatively associated with AIS (regional leptomeningeal collateral [rLMC] scores: OR: 0.798, 95% CI: 0.743-0.857, p < 0.001; Tan scores: OR: 0.478, 95% CI: 0.336-0.679, p < 0.001). Meanwhile, the collateral circulation scores were significantly associated with the recurrence of AIS within 3 years (rLMC scores: OR: 0.926, 95% CI: 0.860-0.997, p = 0.042; Tan scores: OR: 0.467, 95% CI: 0.306-0.712, p < 0.001). Most associations remained significant in the subgroup of patients with VBA stenosis. Favorable collateral circulation in multiple craniocervical artery stenosis patients reduced long-term ischemic event recurrence. Stratifying treatment risks is essential for optimizing outcomes.

Unveiling the impact of DNA methylation machinery: Dnmt1 and Dnmt3a in orchestrating oocyte development and cellular homeostasis.

DNA methylation can be considered the most prominent in controlling the gene expression responsible for the balance between cell proliferation and cell death. In this study, we aimed to analyze the distinct contributions of Dnmt1 and Dnmt3a enzymes in oocyte maturation, survival, autophagy, reactive oxygen species (ROS) production, and compensation capacity of Dnmt3b and Dnmt3l enzymes in mouse oocytes. Following confirming the suppression of Dnmt1or Dnmt3a through siRNA application, the assessment involved immunofluorescence staining for Dnmts, 5mC, p62, and ROS levels. Cell death rates showed a noticeable increase while oocyte maturation rates exhibited significant reduction. Global DNA methylation showed a decline, concomitant with elevated p62 and ROS levels upon Dnmt1 or Dnmt3a knockdown. Remarkably, silencing of Dnmt1 led to an upsurge in Dnmt3a expression, whereas Dnmt3a knockdown triggered an increase in Dnmt1 levels. Furthermore, Dnmt3l expression exhibited a notable decrease after silencing of either Dnmt1 or Dnmt3a, while Dnmt3b levels remained comparable between control and siRNA-treated groups. Collectively, this study underscores the pivotal roles of Dnmt1 and Dnmt3a in orchestrating various facets of oocyte development, encompassing maturation, survival, autophagy, and ROS production. These findings offer valuable insights into the intricate regulatory network governed by DNA methylation machinery within the context of oocyte physiology.

Solar-pumped dual-rod Ce:Nd:YAG laser with 58W continuous-wave output power and 5.1° tracking error compensation width.

The pursuit of high-power solar laser systems with high efficiency and capacity for large tracking error compensation is determinant for the applicability of this renewable technology. A side-pumped dual-rod Ce:Nd:YAG solar laser was developed and tested at the focus of a 2 m diameter parabolic concentrator. Maximum continuous-wave total solar laser power of 58 W was measured. To the best of our knowledge, this is the highest laser power from a Ce:NdYAG solar laser. Moreover, wide tracking error compensation width of 5.1° in the azimuthal direction was reached, being 4.25 times higher than the previous measurement without solar tracking assistance.

Stable Emissions from a Four-Rod Nd:YAG Solar Laser with ±0.5° Tracking Error Compensation Capacity

Conventional solar-pumped lasers rely on expensive and highly accurate solar tracking systems, which present a significant economic barrier to both solar laser research and practical applications. To address this challenge, an end-side-pumped four-rod solar laser head was designed and built for testing at PROMES-CNRS. Solar radiation was collected and concentrated using a heliostat–parabolic mirror system. A fused silica aspheric lens further concentrated the solar rays into a flux homogenizer within which four Nd:YAG rods were symmetrically positioned around a reflective cone and cooled by water. Four partially reflective mirrors were precisely aligned to extract continuous-wave 1064 nm solar laser power from each laser rod. The prototype demonstrated stable multibeam solar laser operation with the solar tracking system turned on. Even when the tracking system was turned off, the total output power extracted from the solar-pumped laser remained stable for 1 min, representing, to the best of our knowledge, the first successful demonstration of a stable multibeam solar laser operation without solar tracking. For typical solar tracking errors up to ±0.5°, the loss in the total solar laser power produced was only about 1%, representing an 8.0-fold improvement over the previous solar laser experiments under tracking error conditions.