To the Editor:Acute myocardial infarction(AMI)poses a substantial threat to human health.^([1])At present,AMI is mainly treated by reperfusion,drugs,and surgery,^([2])which only temporarily delay cell death and deteri...To the Editor:Acute myocardial infarction(AMI)poses a substantial threat to human health.^([1])At present,AMI is mainly treated by reperfusion,drugs,and surgery,^([2])which only temporarily delay cell death and deterioration.Sian Harding at el^([3])suggested that myocardial transfer of specific bone marrow cells(BMCs)and progenitor cell populations may enhance recovery of systolic and diastolic function after AMI.Although a few previous meta-analysis studies of BMCs transplantation for AMI have been published,the quality of these studies was varied due to marked heterogeneity^([4,5])or because they focused on a single outcome(e.g.,cardiac function)[5]and very few evaluated the clinical evens.^([6])In addition,the effects of BMCs transplantation over different lengths of follow-up periods were unclear.In an attempt to reach more reliable conclusions,we performed an updated meta-analysis of randomized controlled trials(RCTs)and conducted subgroup analyses according to follow-up periods.展开更多
Dynamic reactive power compensation equipment typically requires a fast response to output the necessary reactive power.The term"dynamic response time of reactive power"is often used but has never been clear...Dynamic reactive power compensation equipment typically requires a fast response to output the necessary reactive power.The term"dynamic response time of reactive power"is often used but has never been clearly defined.This paper summarizes the reactive power calculations under different definitions and algorithms and considers these calculations in terms of signal processing to simulate and analyze the step response.This paper subsequently focuses on the widely used instantaneous reactive power algorithm and finally concludes that the dynamic reactive power response time closely depends on the reactive power calculation method itself.The single-phase instantaneous reactive power algorithm has the fastest response time.The reactive power response time of dynamic reactive devices in power systems is a minimum of a quarter of one cycle time for the well-known and widely used single-phase reactive power algorithms.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.81960614)International scientific and technological cooperation project(No.20YF3WA020).
文摘To the Editor:Acute myocardial infarction(AMI)poses a substantial threat to human health.^([1])At present,AMI is mainly treated by reperfusion,drugs,and surgery,^([2])which only temporarily delay cell death and deterioration.Sian Harding at el^([3])suggested that myocardial transfer of specific bone marrow cells(BMCs)and progenitor cell populations may enhance recovery of systolic and diastolic function after AMI.Although a few previous meta-analysis studies of BMCs transplantation for AMI have been published,the quality of these studies was varied due to marked heterogeneity^([4,5])or because they focused on a single outcome(e.g.,cardiac function)[5]and very few evaluated the clinical evens.^([6])In addition,the effects of BMCs transplantation over different lengths of follow-up periods were unclear.In an attempt to reach more reliable conclusions,we performed an updated meta-analysis of randomized controlled trials(RCTs)and conducted subgroup analyses according to follow-up periods.
文摘Dynamic reactive power compensation equipment typically requires a fast response to output the necessary reactive power.The term"dynamic response time of reactive power"is often used but has never been clearly defined.This paper summarizes the reactive power calculations under different definitions and algorithms and considers these calculations in terms of signal processing to simulate and analyze the step response.This paper subsequently focuses on the widely used instantaneous reactive power algorithm and finally concludes that the dynamic reactive power response time closely depends on the reactive power calculation method itself.The single-phase instantaneous reactive power algorithm has the fastest response time.The reactive power response time of dynamic reactive devices in power systems is a minimum of a quarter of one cycle time for the well-known and widely used single-phase reactive power algorithms.
