Background Atherosclerotic plaques indicate the occurrence of ischemia events and it is a difficult task for clinical physicians. Grape seed proanthocyanidin extract （GSPE） has been reported to exert an antiatheroge...Background Atherosclerotic plaques indicate the occurrence of ischemia events and it is a difficult task for clinical physicians. Grape seed proanthocyanidin extract （GSPE） has been reported to exert an antiatherogenic effect by inducing regression of atherosclerotic plaques in animal experimental studies. In this study, the antiatherogenic effect of GSPE has been investigated in clinical use. Methods Consecu- tive 287 patients diagnosed with asymptomatic carotid plaques or abnormal plaque free carotid intima-media thickness （CIMT） were ran- domly assigned to the GSPE group （n = 146） or control group （n = 141）. The patients in the GSPE group received GSPE 200 mg per day orally, while patients in the control group were only enrolled in a lifestyle intervention program. Carotid ultrasound examination was per- formed at baseline and 6, 12, 24 months during follow-up. Mean maximum CIMT （MMCIMT）, plaque score, echogenicity of plaques and ischemic vascular events were recorded. Results As anticipated, after treatment, GSPE resulted in significant reduction in MMCIMT pro- gression （4.2% decrease after six months, 4.9% decrease after 12 months and 5.8% decrease after 24 months） and plaque score （10.9% de- crease after six months, 24.1% decrease after 12 months and 33.1% decrease after 24 months） for the primary outcome, while MMCIMT and plaque score were stable and even increased with the time going on in control group. The number of plaques and unstable plaques also de- creased after treatment of GSPE. Furthermore, the carotid plaque can disappear after treatment with GSPE. The incidence rate for transitory ischemic attack （TIA）, arterial revascularization procedure, and hospital readmission for unstable angina in GSPE group were statistically significant lower （P = 0.02, 0.08, 0.002, respectively） compared with the control group. Conclusions GSPE inhibited the progression of MMCIMT and reduced carotid plaque size in GSPE treated patients, and with extended treatment, the superior efficacy on MMCIMT and carotid plaque occurred. Furthermore, the GSPE group showed lower rates of clinical vascular events.展开更多
To design a more effective blade pitch adjustment mechanism,research was done on changes to the hydrodynamic characteristics of VVPs(Variable Vector Propeller) caused by different rules for changing pitch angle. A mat...To design a more effective blade pitch adjustment mechanism,research was done on changes to the hydrodynamic characteristics of VVPs(Variable Vector Propeller) caused by different rules for changing pitch angle. A mathematical method for predicting the hydrodynamic characteristics of a VVP under unsteady conditions is presented based on the panel method. Mathematical models for evaluation based on potential flow theory and the Green theorem are also presented. The hydrodynamic characteristics are numerically predicted. To avoid gaps between panels,hyperboloidal quadrilateral panels were used. The pressure Kutta condition on the trailing edge of the VVP blade was satisfied by the Newton-Raphson iterative procedure. The influence coefficients of the panels were calculated by Morino's analytical formulations to improve numerical calculation speed,and the method developed by Yanagizawa was used to eliminate the point singularity on derivation calculus while determining the velocities on propeller surfaces. The calculation results show that it's best for the hydrodynamic characteristics of the VVP that pitch angle changes follow the sine rule.展开更多
The speed of a ship sailing in waves always slows down due to the decrease in efficiency of the propeller. So it is necessary and essential to analyze the unsteady hydrodynamic performance of propeller in waves. This ...The speed of a ship sailing in waves always slows down due to the decrease in efficiency of the propeller. So it is necessary and essential to analyze the unsteady hydrodynamic performance of propeller in waves. This paper is based on the numerical simulation and experimental research of hydrodynamics performance when the propeller is under wave conditions. Open-water propeller performance in calm water is calculated by commercial codes and the results are compared to experimental values to evaluate the accuracy of the numerical simulation method. The first-order Volume of Fluid(VOF) wave method in STAR CCM+ is utilized to simulate the three-dimensional numerical wave. According to the above prerequisite, the numerical calculation of hydrodynamic performance of the propeller under wave conditions is conducted, and the results reveal that both thrust and torque of the propeller under wave conditions reveal intense unsteady behavior. With the periodic variation of waves, ventilation, and even an effluent phenomenon appears on the propeller. Calculation results indicate, when ventilation or effluent appears, the numerical calculation model can capture the dynamic characteristics of the propeller accurately, thus providing a significant theory foundation forfurther studying the hydrodynamic performance of a propeller in waves.展开更多
1 Introduction Ischemic heart disease is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spec- trum of ischemic heart disease expands from asymptomatic atherosclerosis of corona...1 Introduction Ischemic heart disease is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spec- trum of ischemic heart disease expands from asymptomatic atherosclerosis of coronary arteries to acute coronary syn- dromes （ACS） including unstable angina, acute myocardial infarction （non-ST elevation myocardial infarction and ST elevation myocardial infarction）. Stable ischemic heart dis- ease （SIHD） refers to patients with known or suspected SIHD who have no recent or acute changes in their symp- tomatic status, suggesting no active thrombotic process is underway.展开更多
In order to explain the mechanism for gas outburst, the process of evolving fractures in coal seams is described using system dynamics with variable boundaries. We discuss the failure modes of coal containing gas and ...In order to explain the mechanism for gas outburst, the process of evolving fractures in coal seams is described using system dynamics with variable boundaries. We discuss the failure modes of coal containing gas and then established the flow rules after failure. The condition under which states of deformation convert is presented and the manner in which these convert is proposed. In the end, the process of gas outbursts is explained in detail. It shows that a gas outburst is a process in which the boundaries of coal seams are variable because of coal failure. If the fractures are not connected or even closed owing to coal/rock stress, fractured zones will retain a certain level of carrying capacity because of the self-sealing gas pressure. When the accumulation of gas energy reaches its limit, coal seams will become unstable and gas outbursts take place.展开更多
Acute coronary syndrome （ACS） refers to a spectrum of clinical presentations ranging from unstable angina to non-ST-segment elevation myocardial infarction （NSTEMI） to ST-segment elevation myocardial infarction （...Acute coronary syndrome （ACS） refers to a spectrum of clinical presentations ranging from unstable angina to non-ST-segment elevation myocardial infarction （NSTEMI） to ST-segment elevation myocardial infarction （STEMI）. Aortic dissection, intramural hematoma and penetrating atherosclerotic ulcer （PAU） are three major acute aortic syndromes （AAS）.展开更多
文摘Background Atherosclerotic plaques indicate the occurrence of ischemia events and it is a difficult task for clinical physicians. Grape seed proanthocyanidin extract （GSPE） has been reported to exert an antiatherogenic effect by inducing regression of atherosclerotic plaques in animal experimental studies. In this study, the antiatherogenic effect of GSPE has been investigated in clinical use. Methods Consecu- tive 287 patients diagnosed with asymptomatic carotid plaques or abnormal plaque free carotid intima-media thickness （CIMT） were ran- domly assigned to the GSPE group （n = 146） or control group （n = 141）. The patients in the GSPE group received GSPE 200 mg per day orally, while patients in the control group were only enrolled in a lifestyle intervention program. Carotid ultrasound examination was per- formed at baseline and 6, 12, 24 months during follow-up. Mean maximum CIMT （MMCIMT）, plaque score, echogenicity of plaques and ischemic vascular events were recorded. Results As anticipated, after treatment, GSPE resulted in significant reduction in MMCIMT pro- gression （4.2% decrease after six months, 4.9% decrease after 12 months and 5.8% decrease after 24 months） and plaque score （10.9% de- crease after six months, 24.1% decrease after 12 months and 33.1% decrease after 24 months） for the primary outcome, while MMCIMT and plaque score were stable and even increased with the time going on in control group. The number of plaques and unstable plaques also de- creased after treatment of GSPE. Furthermore, the carotid plaque can disappear after treatment with GSPE. The incidence rate for transitory ischemic attack （TIA）, arterial revascularization procedure, and hospital readmission for unstable angina in GSPE group were statistically significant lower （P = 0.02, 0.08, 0.002, respectively） compared with the control group. Conclusions GSPE inhibited the progression of MMCIMT and reduced carotid plaque size in GSPE treated patients, and with extended treatment, the superior efficacy on MMCIMT and carotid plaque occurred. Furthermore, the GSPE group showed lower rates of clinical vascular events.
文摘To design a more effective blade pitch adjustment mechanism,research was done on changes to the hydrodynamic characteristics of VVPs(Variable Vector Propeller) caused by different rules for changing pitch angle. A mathematical method for predicting the hydrodynamic characteristics of a VVP under unsteady conditions is presented based on the panel method. Mathematical models for evaluation based on potential flow theory and the Green theorem are also presented. The hydrodynamic characteristics are numerically predicted. To avoid gaps between panels,hyperboloidal quadrilateral panels were used. The pressure Kutta condition on the trailing edge of the VVP blade was satisfied by the Newton-Raphson iterative procedure. The influence coefficients of the panels were calculated by Morino's analytical formulations to improve numerical calculation speed,and the method developed by Yanagizawa was used to eliminate the point singularity on derivation calculus while determining the velocities on propeller surfaces. The calculation results show that it's best for the hydrodynamic characteristics of the VVP that pitch angle changes follow the sine rule.
基金Supported by the National Natural Science Foundation of China （51379043, 41176074, 51209048, 51409063）, High Tech Ship Research Project of Ministry of Industry and Technology （G014613002）, and the Support Plan for Youth Backbone Teachers of Harbin Engineering University （HEUCFQ 1408）
文摘The speed of a ship sailing in waves always slows down due to the decrease in efficiency of the propeller. So it is necessary and essential to analyze the unsteady hydrodynamic performance of propeller in waves. This paper is based on the numerical simulation and experimental research of hydrodynamics performance when the propeller is under wave conditions. Open-water propeller performance in calm water is calculated by commercial codes and the results are compared to experimental values to evaluate the accuracy of the numerical simulation method. The first-order Volume of Fluid(VOF) wave method in STAR CCM+ is utilized to simulate the three-dimensional numerical wave. According to the above prerequisite, the numerical calculation of hydrodynamic performance of the propeller under wave conditions is conducted, and the results reveal that both thrust and torque of the propeller under wave conditions reveal intense unsteady behavior. With the periodic variation of waves, ventilation, and even an effluent phenomenon appears on the propeller. Calculation results indicate, when ventilation or effluent appears, the numerical calculation model can capture the dynamic characteristics of the propeller accurately, thus providing a significant theory foundation forfurther studying the hydrodynamic performance of a propeller in waves.
文摘1 Introduction Ischemic heart disease is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spec- trum of ischemic heart disease expands from asymptomatic atherosclerosis of coronary arteries to acute coronary syn- dromes （ACS） including unstable angina, acute myocardial infarction （non-ST elevation myocardial infarction and ST elevation myocardial infarction）. Stable ischemic heart dis- ease （SIHD） refers to patients with known or suspected SIHD who have no recent or acute changes in their symp- tomatic status, suggesting no active thrombotic process is underway.
基金financial support from the National Basic Research Program of China (No.2005CB221500)the National Natural Science Foundation of China (Nos.50534049,50674087 and 50974107)the Natural Science Foundation of Jiangsu Province (No.BK2007029)
文摘In order to explain the mechanism for gas outburst, the process of evolving fractures in coal seams is described using system dynamics with variable boundaries. We discuss the failure modes of coal containing gas and then established the flow rules after failure. The condition under which states of deformation convert is presented and the manner in which these convert is proposed. In the end, the process of gas outbursts is explained in detail. It shows that a gas outburst is a process in which the boundaries of coal seams are variable because of coal failure. If the fractures are not connected or even closed owing to coal/rock stress, fractured zones will retain a certain level of carrying capacity because of the self-sealing gas pressure. When the accumulation of gas energy reaches its limit, coal seams will become unstable and gas outbursts take place.
文摘Acute coronary syndrome （ACS） refers to a spectrum of clinical presentations ranging from unstable angina to non-ST-segment elevation myocardial infarction （NSTEMI） to ST-segment elevation myocardial infarction （STEMI）. Aortic dissection, intramural hematoma and penetrating atherosclerotic ulcer （PAU） are three major acute aortic syndromes （AAS）.
