A novel mouse model of calcific aortic valve stenosis

Background:Calcific aortic valve stenosis(CAVS)is one of the most challenging heart diseases in clinical with rapidly increasing prevalence.However,study of the mecha-nism and treatment of CAVS is hampered by the lack of suitable,robust and efficient models that develop hemodynamically significant stenosis and typical calcium deposi-tion.Here,we aim to establish a mouse model to mimic the development and features of CAVS.Methods:The model was established via aortic valve wire injury(AVWI)combined with vitamin D subcutaneous injected in wild type C57/BL6 mice.Serial transthoracic echocardiography was applied to evaluate aortic jet peak velocity and mean gradi-ent.Histopathological specimens were collected and examined in respect of valve thickening,calcium deposition,collagen accumulation,osteogenic differentiation and inflammation.Results:Serial transthoracic echocardiography revealed that aortic jet peak velocity and mean gradient increased from 7 days post model establishment in a time depend-ent manner and tended to be stable at 28 days.Compared with the sham group,sim-ple AVWI or the vitamin D group,the hybrid model group showed typical pathological features of CAVS,including hemodynamic alterations,increased aortic valve thicken-ing,calcium deposition,collagen accumulation at 28 days.In addition,osteogenic dif-ferentiation,fibrosis and inflammation,which play critical roles in the development of CAVS,were observed in the hybrid model.Conclusions:We established a novel mouse model of CAVS that could be induced efficiently,robustly and economically,and without genetic intervention.It provides a fast track to explore the underlying mechanisms of CAVS and to identify more effec-tive pharmacological targets.

Stable partial nitritation of mature landfill leachate in a continuous flow bioreactor:Long-term performance,microbial community evolution,and mechanisms

A continuous flow bioreactor was operated for 300 days to investigate partial nitritation(PN)of mature landfill leachate,establishing the long-term performance of the system in terms of the microbial community composition,evolution,and interactions.The stable operation phase(31-300 d)began after a 30 days of start-up period,reaching an average nitrite accumulation ratio(NAR)of 94.43%and a ratio of nitrite nitrogen to ammonia nitrogen(NO_(2)^(−)-N/NH_(4)^(+)-N)of 1.16.Some fulvic-like and humic-like compounds and proteins were effectively degraded in anaerobic and anoxic tanks,which was consistent with the corresponding abundance of methanogens and syntrophic bacteria in the anaerobic tank,and organic matter degrading bacteria in the anoxic tank.The ammonia-oxidizing bacteria(AOB)Nitrosomonas was found to be the key functional bacteria,exhibiting an increase in abundance from 0.27%to 6.38%,due to its collaborative interactions with organic matter degrading bacteria.In-situ inhibition of nitrite-oxidizing bacteria(NOB)was achieved using a combination of free ammonia(FA)and free nitrous acid(FNA),low dissolved oxygen(DO)with fewer bioavailable organics conditions were employed to maintain stable PN and a specific ratio of NO_(2)^(−)-N/NH_(4)^(+)-N,without an adverse impact on AOB.The synergistic relationships between AOB and both denitrifying bacteria and organic matter degrading bacteria,were found to contribute to the enhanced PN performance and microbial community structure stability.These findings provide a theoretical guidance for the effective application of PN-Anammox for mature landfill leachate treatment.

Cerebral ischemic injury after transcatheter aortic valve replacement in patients with pure aortic regurgitation

Considering the surgical risk stratification for patients with severe calcific aortic stenosis(AS),transcatheter aortic valve replacement(TAVR)is a reliable alternative to surgical aortic valve replacement(SAVR)(Fan et al.,2020,2021;Lee et al.,2021).Despite the favorable clinical benefits of TAVR,stroke remains a dreaded perioperative complication(Auffret et al.,2016;Kapadia et al.,2016;Kleiman et al.,2016;Huded et al.,2019).Ischemic overt stroke,identified in 1.4%to 4.3%of patients in TAVR clinical practice,has been associated with prolonged disability and increased mortality(Auffret et al.,2016;Kapadia et al.,2016;Levi et al.,2022).The prevalence of hyperintensity cerebral ischemic lesions detected by diffusion-weighted magnetic resonance imaging(DW-MRI)was reported to be about 80%,which is associated with impaired neurocognitive function and vascular dementia(Vermeer et al.,2003;Barber et al.,2008;Kahlert et al.,2010).

Data quality issues for synchrophasor applications PartⅠ:a review

Synchrophasor systems, providing low-latency,high-precision, and time-synchronized measurements to enhance power grid performances, are deployed globally.However, the synchrophasor system as a physical network,involves communication constraints and data quality issues, which will impact or even disable certain synchrophasor applications. This work investigates the data quality issue for synchrophasor applications. In Part I, the standards of synchrophasor systems and the classifications and data quality requirements of synchrophasor applications are reviewed. Also, the actual events of synchronization signal accuracy, synchrophasor data loss, and latency are counted and analyzed. The review and statistics are expected to provide an overall picture of data accuracy,loss, and latency issues for synchrophasor applications.

Data quality issues for synchrophasor applications Part Ⅱ:problem formulation and potential solutions

This work investigates the data quality issue for synchrophasor applications, and pays particular attention to synchronization signal loss and synchrophasor data loss events. First, the historical synchronization signal loss events are analyzed and the potential reasons and solutions are discussed. Then, the scenario of a small amount of synchrophasor data loss is studied and a Lagrange interpolating polynomial method is used to adaptively estimate the incomplete and missing data. The performance of proposed method is demonstrated with simulation results.Specifically, the proposed method considers the trade-off between the estimation accuracy and the hardware cost,and could be efficiently employed in reality.

Modelling, Implementation, and Assessment of Virtual Synchronous Generator in Power Systems

As more and more power electronic based generation units are integrated into power systems, the stable operation of power systems has been challenged due to the lack of system inertia. In order to solve this issue, the virtual synchronous generator(VSG), in which the power electronic inverter is controlled to mimic the characteristics of traditional synchronous generators, is a promising strategy. In this paper, the representation of the synchronous generator in power systems is firstly presented as the basis for the VSG. Then the modelling methods of VSG are comprehensively reviewed and compared.Applications of the VSG in power systems are summarized as well. Finally, the challenges and future trends of the VSG implementation are discussed.

Recent Developments of FNET/GridEye—A Situational Awareness Tool for Smart Grid

Wide-area monitoring systems(WAMS)are becoming increasingly vital for enhancing power grid operators’situational awareness capabilities.As a pilot WAMS that was initially deployed in 2003,the frequency monitoring network FNET/GridEye uses GPS-time-synchronized monitors called frequency disturbance recorders(FDRs)to capture dynamic grid behaviors.Over the past ten years,a large number of publications related to FNET/GridEye have been reported.In this paper,the most recent developments of FNET/GridEye sensors,data centers,and data analytics applications are reviewed.These works demonstrate that FNET/GridEye will become a costeffective situational awareness tool for the future smart grid.

Response of aerobic sludge to AHL-mediated QS:Granulation,simultaneous nitrogen and phosphorus removal performance

The effects of different species and concentrations’signal molecules on aerobic activated sludge system were investigated through batch experiments.Results showed that the fastest NH^(+)_(4)-N oxidization rate and the most extracellular polymeric substances(EPS)secretion were obtained by adding 5 nmol/L N-hexanoyl-l-homoserine lactone(C_(6)-HSL)into the aerobic activated sludge.Further study investigated the correlation among N-acyl-homoserine lactones-mediated quorum sensing(AHLs-mediated QS),nutrient removal performances and microbial communities with the long-term addition of 5 nmol/L C_(6)-HSL.It was found that C_(6)-HSL-manipulation could enhance the stability and optimize the decontamination performance of aerobic granular sludge(AGS)system.Microbial compositions considerably shifted with long-term C_(6)-HSL-manipulation.Exogenous C_(6)-HSL-manipulation inhibited quorum quenching-related(QQ-related)activities and enhanced QS-related activities during the stable period.The proposed C_(6)-HSL-manipulation might be a potential technology to inhibit the growth of harmful bacteria in AGS,which could provide a theoretical foundation for the realization of more stable biological wastewater treatments.

Reliability Analysis of Grid-Interfaced Filter Capacitors

Growing with the increased adoption of renewable energy for the power generation,the reliable and cost-effective operation of grid-connected inverters is of more and more importance.A filter is interfaced between an inverter and the utility grid to reduce the switching harmonics.According to the modulation scheme and the LCL filter impedance,the electrical stresses of the filter capacitor can be thoroughly investigated.With the help of the electro-thermal model,its long-term thermal stress can be obtained based on the mission profile like wind speed,ambient temperature.The reliability of the filter capacitor bank is obtained based on its individual capacitor reliability curves and reliability block diagram method.A case study on a 2MW wind turbine system demonstrates the relationship between the lifetime of the capacitor bank and the single capacitor.Moreover,the severe voltage and current stresses of the filter capacitors are analyzed during abnormal operations(e.g.,fault ride-through)with asymmetrical parasitic parameters.

Modern Control Strategies of Doubly-Fed Induction Generator Based Wind Turbine System

A doubly-fed induction generator(DFIG)based configuration is still preferred by wind turbine manufacturers due to the cost-effective power converter and independent control of the active power and reactive power.To cope with stricter grid codes(e.g.reactive power compensation,low voltage ride-through operation,as well as steady and safe operation during long-term distorted grid),control strategies are continuously evolving.This paper starts with a control strategy using the combined reactive power compensation from both the back-to-back power converters for their optimized lifetime distribution under normal grid conditions.Afterwards,an advanced demagnetizing control is proposed to keep the minimum thermal stress of the rotor-side converter in the case of the short-term grid fault.A modularized control strategy of the DFIG system under unbalanced and distorted grid voltage is discussed,with the control targets of the smooth active and reactive power or the balanced and sinusoidal current of the rotor-side converter and the grid-side converte。Finally,a bandwidth based repetitive controller is evaluated to improve the DFIG system's robustness against grid frequency deviation.