For an underactuated spacecraft using only one thruster, the attitude controllability with respect to the or- bit frame is studied in the presence of periodical oscillation disturbance, which provides a preconditional...For an underactuated spacecraft using only one thruster, the attitude controllability with respect to the or- bit frame is studied in the presence of periodical oscillation disturbance, which provides a preconditional guide on de- signing control law for underactuated attitude control sys- tem. Firstly, attitude dynamic model was established for an underactuated spacecraft, and attitude motion was described using the special orthogonal group （SO （3））. Secondly, Liou- ville theorem was used to confirm that the flow generated by the drift vector of the underactuated attitude control system is volume-preserving. Furthermore, according to Poincar6＇s re- currence theorem, we draw conclusions that this drift field is weakly positively poisson stable （WPPS）. Thirdly, the suffi- cient and necessary condition of controllability was obtained on the basis of lie algebra rank condition （LARC）. Finally, the controllable conditions were analyzed and simulated in different cases of inertia matrix with the installed position of thruster.展开更多
Background： It is currently believed that triple oral antithrombotic therapy in patients with atrial fibrillation （AF） after percutaneous coronary intervention （PCI） should be recommended if there are no contrain...Background： It is currently believed that triple oral antithrombotic therapy in patients with atrial fibrillation （AF） after percutaneous coronary intervention （PCI） should be recommended if there are no contraindications. However, selecting triple therapy for AF patients undergoing PCI is still challenging when bleeding risk is considered. This study aimed to investigate the current use of oral anticoagulants （Vitamin K antagonists [VKA]） and perform prognostic analysis in real-world patients with AF undergoing coronary stenting. Methods： A total of 276 consecutive coronary artery disease （CAD） patients with or without AF undergoing coronary stenting were retrospectively evaluated and analyzed. The univariate and multivariate analyses were conducted to explore the current use of VKA and prognosis of patients with AF undergoing coronary stenting. The primary end-point was composite of all-cause death, nonfatal recurrent myocardial infarction, stroke, serious bleeding events, unplanned repeat revascularization, and worsening heart failure at 12-month follow-up after coronary stenting. Results： AF patients undergoing coronary stenting have more clinical concomitant diseases. Only 9.0% AF patients after coronary stenting received triple antithrombotic therapy （VKA, aspirin, and clopidogrel） at discharge. AF was independently associated with increased risk of the 12-month composite end-points （relative risk = 5.732, 95% confidence interval 1.786-18.396, P = 0.003）. Conclusions： In real-life AF patients undergoing coronary stenting, guideline-recommended VKA was less used. AF patients had adjusted worse prognosis during 12-month follow-up after discharge. It is of utmost importance to improve the current status of oral anticoagulants use.展开更多
基金supported by National Natural Science Foundation of China (10902003)
文摘For an underactuated spacecraft using only one thruster, the attitude controllability with respect to the or- bit frame is studied in the presence of periodical oscillation disturbance, which provides a preconditional guide on de- signing control law for underactuated attitude control sys- tem. Firstly, attitude dynamic model was established for an underactuated spacecraft, and attitude motion was described using the special orthogonal group （SO （3））. Secondly, Liou- ville theorem was used to confirm that the flow generated by the drift vector of the underactuated attitude control system is volume-preserving. Furthermore, according to Poincar6＇s re- currence theorem, we draw conclusions that this drift field is weakly positively poisson stable （WPPS）. Thirdly, the suffi- cient and necessary condition of controllability was obtained on the basis of lie algebra rank condition （LARC）. Finally, the controllable conditions were analyzed and simulated in different cases of inertia matrix with the installed position of thruster.
文摘Background： It is currently believed that triple oral antithrombotic therapy in patients with atrial fibrillation （AF） after percutaneous coronary intervention （PCI） should be recommended if there are no contraindications. However, selecting triple therapy for AF patients undergoing PCI is still challenging when bleeding risk is considered. This study aimed to investigate the current use of oral anticoagulants （Vitamin K antagonists [VKA]） and perform prognostic analysis in real-world patients with AF undergoing coronary stenting. Methods： A total of 276 consecutive coronary artery disease （CAD） patients with or without AF undergoing coronary stenting were retrospectively evaluated and analyzed. The univariate and multivariate analyses were conducted to explore the current use of VKA and prognosis of patients with AF undergoing coronary stenting. The primary end-point was composite of all-cause death, nonfatal recurrent myocardial infarction, stroke, serious bleeding events, unplanned repeat revascularization, and worsening heart failure at 12-month follow-up after coronary stenting. Results： AF patients undergoing coronary stenting have more clinical concomitant diseases. Only 9.0% AF patients after coronary stenting received triple antithrombotic therapy （VKA, aspirin, and clopidogrel） at discharge. AF was independently associated with increased risk of the 12-month composite end-points （relative risk = 5.732, 95% confidence interval 1.786-18.396, P = 0.003）. Conclusions： In real-life AF patients undergoing coronary stenting, guideline-recommended VKA was less used. AF patients had adjusted worse prognosis during 12-month follow-up after discharge. It is of utmost importance to improve the current status of oral anticoagulants use.
