Objective Dexmedetomidine is a highly selective alpha-2 adrenergic receptor agonist with sedative and analgesic properties but without respiratory depression effect and has been widely used in perioperative anesthesia...Objective Dexmedetomidine is a highly selective alpha-2 adrenergic receptor agonist with sedative and analgesic properties but without respiratory depression effect and has been widely used in perioperative anesthesia.Here we performed a systematic review and meta-analysis to evaluate the effect of dexmedetomidine on maintaining perioperative hemodynamic stability in elderly patients.Methods PubMed,Web of Science,the Cochrane Library,China National Knowledge Infrastructure(CNKI),and Wanfang Data were searched for randomized-controlled trials(RCTs)on the application of dexmedetomidine in maintaining perioperative hemodynamic stability in elderly patients from their inception to September,2021.The standardized mean differences(SMD)with 95%confidence interval(CI)were employed to analyze the data.The random-effect model was used for the potential clinical inconsistency.Results A total of 12 RCTs with 833 elderly patients(dexmedetomidine group,546 patients;control group,287 patients)were included.There was no significant increase in perioperative heart rate(HR),mean arterial pressure(MAP),and diastolic blood pressure(DBP)in the dexmedetomidine group before and during the operation.In addition,the variations of hemodynamic indexes including HR,MAP,SBP(systolic blood pressure),and DBP were significantly lower in the dexmedetomidine group compared with the control group(HR:SMD=-0.87,95%CI:-1.13 to-0.62;MAP:SMD=-1.12,95%CI:-1.60 to-0.63;SBP:SMD=-1.27,95%CI:-2.26 to-0.27;DBP:SMD=-0.96,95%CI:-1.33 to-0.59).Subgroup analysis found that with the prolongation of 1.0μg/kg dexmedetomidine infusion,the patient’s heart rate declined in a time-dependent way.Conclusion Dexmedetomidine provides more stable hemodynamics during perioperative period in elderly patients.However,further well-conducted trials are required to assess the effective and safer doses of dexmedetomidine in elderly patients.展开更多
The non-stationary of the motor imagery electroencephalography(MI-EEG)signal is one of the main limitations for the development of motor imagery brain-computer interfaces(MI-BCI).The nonstationary of the MI-EEG signal...The non-stationary of the motor imagery electroencephalography(MI-EEG)signal is one of the main limitations for the development of motor imagery brain-computer interfaces(MI-BCI).The nonstationary of the MI-EEG signal and the changes of the experimental environment make the feature distribution of the testing set and training set deviates,which reduces the classification accuracy of MI-BCI.In this paper,we propose a Kullback–Leibler divergence(KL)-based transfer learning algorithm to solve the problem of feature transfer,the proposed algorithm uses KL to measure the similarity between the training set and the testing set,adds support vector machine(SVM)classification probability to classify and weight the covariance,and discards the poorly performing samples.The results show that the proposed algorithm can significantly improve the classification accuracy of the testing set compared with the traditional algorithms,especially for subjects with medium classification accuracy.Moreover,the algorithm based on transfer learning has the potential to improve the consistency of feature distribution that the traditional algorithms do not have,which is significant for the application of MI-BCI.展开更多
Uniform heating of complex surfaces,especially non-developable surfaces,is a crucial problem that traditional rigid heaters cannot solve.Inspired by flexible electronic devices,a novel design for the stretchable heati...Uniform heating of complex surfaces,especially non-developable surfaces,is a crucial problem that traditional rigid heaters cannot solve.Inspired by flexible electronic devices,a novel design for the stretchable heating film is proposed with the flexible serpentine wire embedded in the soft polymer film,which can be attached to non-developable surfaces conformally.It provides a new way for the stretchable heaters to realize uniform heating of complex surfaces.However,the thermal field of flexible serpentine heaters(FSHs)depends on the configurations of the embedded serpentine heating wire,which requires accurate theoretical prediction of real-time temperature distribution.Therefore,the analytical model for the transient heat conduction in FSHs is solved by the separation of variables method and validated by the finite element analysis(FEA)in this paper.Based on this model,the effects of the geometric parameters,such as the radius and the length of the serpentine heaters,on the thermal uniformity are systematically investigated.This study can help to design and fabricate flexible heaters with uniform heating in the future.展开更多
基金Supported by National High Level Hospital Clinical Research Funding(2022 GSP-QN-16)Yunnan Provincial Cardiovascular Disease Clinical Medical Center Project(FZX2019-06-01).
文摘Objective Dexmedetomidine is a highly selective alpha-2 adrenergic receptor agonist with sedative and analgesic properties but without respiratory depression effect and has been widely used in perioperative anesthesia.Here we performed a systematic review and meta-analysis to evaluate the effect of dexmedetomidine on maintaining perioperative hemodynamic stability in elderly patients.Methods PubMed,Web of Science,the Cochrane Library,China National Knowledge Infrastructure(CNKI),and Wanfang Data were searched for randomized-controlled trials(RCTs)on the application of dexmedetomidine in maintaining perioperative hemodynamic stability in elderly patients from their inception to September,2021.The standardized mean differences(SMD)with 95%confidence interval(CI)were employed to analyze the data.The random-effect model was used for the potential clinical inconsistency.Results A total of 12 RCTs with 833 elderly patients(dexmedetomidine group,546 patients;control group,287 patients)were included.There was no significant increase in perioperative heart rate(HR),mean arterial pressure(MAP),and diastolic blood pressure(DBP)in the dexmedetomidine group before and during the operation.In addition,the variations of hemodynamic indexes including HR,MAP,SBP(systolic blood pressure),and DBP were significantly lower in the dexmedetomidine group compared with the control group(HR:SMD=-0.87,95%CI:-1.13 to-0.62;MAP:SMD=-1.12,95%CI:-1.60 to-0.63;SBP:SMD=-1.27,95%CI:-2.26 to-0.27;DBP:SMD=-0.96,95%CI:-1.33 to-0.59).Subgroup analysis found that with the prolongation of 1.0μg/kg dexmedetomidine infusion,the patient’s heart rate declined in a time-dependent way.Conclusion Dexmedetomidine provides more stable hemodynamics during perioperative period in elderly patients.However,further well-conducted trials are required to assess the effective and safer doses of dexmedetomidine in elderly patients.
文摘The non-stationary of the motor imagery electroencephalography(MI-EEG)signal is one of the main limitations for the development of motor imagery brain-computer interfaces(MI-BCI).The nonstationary of the MI-EEG signal and the changes of the experimental environment make the feature distribution of the testing set and training set deviates,which reduces the classification accuracy of MI-BCI.In this paper,we propose a Kullback–Leibler divergence(KL)-based transfer learning algorithm to solve the problem of feature transfer,the proposed algorithm uses KL to measure the similarity between the training set and the testing set,adds support vector machine(SVM)classification probability to classify and weight the covariance,and discards the poorly performing samples.The results show that the proposed algorithm can significantly improve the classification accuracy of the testing set compared with the traditional algorithms,especially for subjects with medium classification accuracy.Moreover,the algorithm based on transfer learning has the potential to improve the consistency of feature distribution that the traditional algorithms do not have,which is significant for the application of MI-BCI.
基金the National Natural Science Foundation of China(No.11772030)the Aeronautical Science Foundation of China(No.2018ZC51030)+1 种基金the Natural Science Foundation of Zhejiang Province of China(No.Y21A020002)the Opening Fund of State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology(No.GZ19117)。
文摘Uniform heating of complex surfaces,especially non-developable surfaces,is a crucial problem that traditional rigid heaters cannot solve.Inspired by flexible electronic devices,a novel design for the stretchable heating film is proposed with the flexible serpentine wire embedded in the soft polymer film,which can be attached to non-developable surfaces conformally.It provides a new way for the stretchable heaters to realize uniform heating of complex surfaces.However,the thermal field of flexible serpentine heaters(FSHs)depends on the configurations of the embedded serpentine heating wire,which requires accurate theoretical prediction of real-time temperature distribution.Therefore,the analytical model for the transient heat conduction in FSHs is solved by the separation of variables method and validated by the finite element analysis(FEA)in this paper.Based on this model,the effects of the geometric parameters,such as the radius and the length of the serpentine heaters,on the thermal uniformity are systematically investigated.This study can help to design and fabricate flexible heaters with uniform heating in the future.
