In this paper,areas and main factors of wind erosion in black earth region of Northeast China were systematically analyzed,as well as the development trend of wind erosion in black earth region of Northeast China.In a...In this paper,areas and main factors of wind erosion in black earth region of Northeast China were systematically analyzed,as well as the development trend of wind erosion in black earth region of Northeast China.In addition,development trend of wind erosion in black earth region of Northeast China was analyzed from the aspects of the geographic position,climatic change law in recent 40 years and effects of northeast sand land desertification on wind erosion in black earth region,which had provided references for the research and prevention of wind erosion in soil of black earth region of Northeast China.展开更多
With in vitro spin labeling electron spin resonance (ESR) spectroscopy, we have studied the effects of Bu Yang Huan Wu (BYHW) decoction and its effective constituents such as astragaloside IV ferulic acid, chua...With in vitro spin labeling electron spin resonance (ESR) spectroscopy, we have studied the effects of Bu Yang Huan Wu (BYHW) decoction and its effective constituents such as astragaloside IV ferulic acid, chuanxiongzine, rutin, chlorogenic acid, 9,10 dimethoxy pterocarpane 7 O β D glucoside, calycosin, formononetin, calycosin 7 O glucoside, paeoniflorin, paeonal and quercein on the cell membrane fluidity of a rat brain which was modeled after the dual cervical arteries were intercepted and released for realizing an ischemia reperfusion injury which was selected as a brain stroke model. Our results indicated that the cell membrane fluidity in the model group decreased approximately 8% compared with the control group, and after brain cells were incubatied with species, the membrane fluidity could be recovered closely to the control level depending on the BYHW decoction and its different constituents. As the membrane fluidity is a very sensitive biological index which reflectsd the cell status, our method will be useful to study the molecular mechanism of tradition Chinese medicine (TCM) and its combination recipe.展开更多
AIM: To investigate the population-based prevalence of fatty liver disease (FLD) and its risk factors in Guangdong Province,China. METHODS: A cross-sectional survey with multiple-stage stratified cluster and random sa...AIM: To investigate the population-based prevalence of fatty liver disease (FLD) and its risk factors in Guangdong Province,China. METHODS: A cross-sectional survey with multiple-stage stratified cluster and random sampling of inhabitants over 7-year-old was performed in 6 urban and rural areas of Guangdong Province,China. Questionnaires,designed by co-working of epidemiologists and hepatologists,included demographic characteristics,current medication use,medical history and health-relevant behaviors,i.e. alcohol consumption,smoking habits,dietary habits and physical activities. Anthropometric measurements,biochemical tests and abdominal ultrasonography were carried out. RESULTS: Among the 3543 subjects,609 (17.2%) were diagnosed having FLD (18.0% males,16.7% females,P > 0.05). Among them,the prevalence of confirmed alcoholic liver disease (ALD),suspected ALD and nonalcoholic fatty liver disease (NAFLD) were 0.4%,1.8%,and 15.0%,respectively. The prevalence rate (23.0%) was significantly higher in urban areas than (12.9%) in rural areas. After adjustment for age,gender and residency,the standardized prevalence of FLD in adults was 14.5%. Among them,confirmed ALD,suspected ALD and NAFLD were 0.5%,2.3%,and 11.7%,respectively,in adults and 1.3% (all NAFLD) in children at the age of 7-18 years. The overall prevalence of FLD increased with age in both genders to the peak of 27.4% in the group of subjects at the age of 60-70 years. The prevalence rate was significantly higher in men than in women under the age of 50 years (22.4% vs 7.1%,P < 0.001). However,the opposite phenomenon was found over the age of 50 years (20.6% vs 27.6%,P < 0.05). Multivariate and logistic regression analysis indicated that male gender,urban residency,low education,high blood pressure,body mass index,waist circumference,waist to hip ratio,serum triglyceride and glucose levels were the risk factors for FLD. CONCLUSION: FLD,especially NAFLD,is prevalent in South China. There are many risk factors for FLD.展开更多
Objective To investigate the prevalence of peripheral arterial disease (PAD) in China type 2 diabetic patients and to demonstrate the relationships between putative risk factors and PAD. Methods In total 1 397 type 2 ...Objective To investigate the prevalence of peripheral arterial disease (PAD) in China type 2 diabetic patients and to demonstrate the relationships between putative risk factors and PAD. Methods In total 1 397 type 2 diabetic patients aged 50 years and older were enrolled and determined ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) in 15 Class III Grade A hospitals in 7 major cities of China. Results Mean patient age was 63.7±8.2 years and mean duration of diabetes mellitus was 9.39±7.4 years. Two hundreds and seventy-two (19.47%) patients were diagnosed as PAD by ABI <0.9, 122 (18.37%) in male and 150 (20.46%) in female. PAD patients had a significantly longer duration of diabetes mellitus, higher hemoglobin Alc, and a significantly lower mean body mass index than non-PAD ones. Aging, smoking, and systolic blood pressure were found to be positively related with the prevalence of PAD. In terms of lipid profiles, no variable was found to relate with PAD. Notably, baPWV showed as the same significant guiding index for PAD, almost matched with ABI. Conclusions PAD is a common complication in China type 2 diabetic patients. Therefore, PAD screening and treatment should be emphasized for diabetic patients with high risk factors.展开更多
Using daily NCEP/NCAR reanalysis dataset and observation rainfall data in China for the 1971-2000 period, a subtropical summer monsoon index has been defined by meridional moisture transport of the total atmosphere co...Using daily NCEP/NCAR reanalysis dataset and observation rainfall data in China for the 1971-2000 period, a subtropical summer monsoon index has been defined by meridional moisture transport of the total atmosphere column. Results show that the subtropical summer monsoon index defined by the difference of meridional moisture transport between South China and North China can be used to describe the intensity of the subtropical summer monsoon. High (low) index is corresponding to strong (weak) subtropical summer monsoon. And the new index is well related to the summer rainfall over the middle and lower reaches of Yangtze River. In addition, the convergence of moisture transport from the west Pacific via the South China Sea and that from the North China may be responsible for the anomalously excessive summer rainfall over the middle and lower reaches of Yangtze River.展开更多
AIM: To determine the prevalence and symptoms of gastroesophageal reflux disease (GERD) in a healthy general population in relation to demographic,lifestyle and health-seeking behaviors in Shiraz,southern Iran. METHOD...AIM: To determine the prevalence and symptoms of gastroesophageal reflux disease (GERD) in a healthy general population in relation to demographic,lifestyle and health-seeking behaviors in Shiraz,southern Iran. METHODS: A total of 1978 subjects aged > 35 years who referred to Gastroenterohepatology Research Center and who completed a questionnaire consisting of 27 questions for GERD in relation to demographic,lifestyle and health-seeking behaviors were included in this study for a period of five months. The validity and reliability of the questionnaire were determined. RESULTS: The prevalence of GERD was 15.4%,which was higher in females (17.3%),in rural areas (19.8%),and in illiterate subjects (21.5%) and those with a mean age of 50.25 years. The prevalence was significantly lower in subjects having fried food (14.8%),and fruit and vegetables (14.6%). More symptoms were noticed in subjects consuming pickles (22.1%),taking aspirin (21%) and in subjects with psychological distresses (27.2%) and headaches (22%). The correlation was statistically significant between GERD and halitosis (18.3%),dyspepsia (30.6%),anxiety (19.5%),nightmares (23.9%) and restlessness (18.5%). Their health seeking behavior showed that there was a significant restriction of diet (20%),consumption of herbal medicine (19%),using over-the-counter drugs (29.9%) and consulting with physicians (24.8%). Presence of GERD symptoms was also significantly related to a previous family history of the disease (22.3%).CONCLUSION: GERD is more common in females,rural and illiterate subjects and correlated with consumption of pickles,occurrence of headache,psychological distress,dyspepsia,halitosis,anxiety,nightmare and restlessness,and a family history of GERD and aspirin intake,but the correlation was negative with consumption of fat and fiber intake.展开更多
This paper proposes an analysis and a direct power control (DPC) design of a wind turbine driven doubly-fed induction generator (DFIG) under unbalanced network voltage conditions. A DFIG model described in the positiv...This paper proposes an analysis and a direct power control (DPC) design of a wind turbine driven doubly-fed induction generator (DFIG) under unbalanced network voltage conditions. A DFIG model described in the positive and negative synchronous reference frames is presented. Variations of the stator output active and reactive powers are fully deduced in the presence of negative sequence supply voltage and rotor flux. An enhanced DPC scheme is proposed to eliminate stator active power oscillation during network unbalance. The proposed control scheme removes rotor current regulators and the decomposition processing of positive and negative sequence rotor currents. Simulation results using PSCAD/EMTDC are presented on a 2-MW DFIG wind power generation system to validate the feasibility of the proposed control scheme under balanced and unbalanced network conditions.展开更多
基金Supported by National Natural Science Foundation of China(40901136)~~
文摘In this paper,areas and main factors of wind erosion in black earth region of Northeast China were systematically analyzed,as well as the development trend of wind erosion in black earth region of Northeast China.In addition,development trend of wind erosion in black earth region of Northeast China was analyzed from the aspects of the geographic position,climatic change law in recent 40 years and effects of northeast sand land desertification on wind erosion in black earth region,which had provided references for the research and prevention of wind erosion in soil of black earth region of Northeast China.
文摘With in vitro spin labeling electron spin resonance (ESR) spectroscopy, we have studied the effects of Bu Yang Huan Wu (BYHW) decoction and its effective constituents such as astragaloside IV ferulic acid, chuanxiongzine, rutin, chlorogenic acid, 9,10 dimethoxy pterocarpane 7 O β D glucoside, calycosin, formononetin, calycosin 7 O glucoside, paeoniflorin, paeonal and quercein on the cell membrane fluidity of a rat brain which was modeled after the dual cervical arteries were intercepted and released for realizing an ischemia reperfusion injury which was selected as a brain stroke model. Our results indicated that the cell membrane fluidity in the model group decreased approximately 8% compared with the control group, and after brain cells were incubatied with species, the membrane fluidity could be recovered closely to the control level depending on the BYHW decoction and its different constituents. As the membrane fluidity is a very sensitive biological index which reflectsd the cell status, our method will be useful to study the molecular mechanism of tradition Chinese medicine (TCM) and its combination recipe.
基金Supported by a Grant from Guangzhou Health Bureau Project, No. 2004-Z001
文摘AIM: To investigate the population-based prevalence of fatty liver disease (FLD) and its risk factors in Guangdong Province,China. METHODS: A cross-sectional survey with multiple-stage stratified cluster and random sampling of inhabitants over 7-year-old was performed in 6 urban and rural areas of Guangdong Province,China. Questionnaires,designed by co-working of epidemiologists and hepatologists,included demographic characteristics,current medication use,medical history and health-relevant behaviors,i.e. alcohol consumption,smoking habits,dietary habits and physical activities. Anthropometric measurements,biochemical tests and abdominal ultrasonography were carried out. RESULTS: Among the 3543 subjects,609 (17.2%) were diagnosed having FLD (18.0% males,16.7% females,P > 0.05). Among them,the prevalence of confirmed alcoholic liver disease (ALD),suspected ALD and nonalcoholic fatty liver disease (NAFLD) were 0.4%,1.8%,and 15.0%,respectively. The prevalence rate (23.0%) was significantly higher in urban areas than (12.9%) in rural areas. After adjustment for age,gender and residency,the standardized prevalence of FLD in adults was 14.5%. Among them,confirmed ALD,suspected ALD and NAFLD were 0.5%,2.3%,and 11.7%,respectively,in adults and 1.3% (all NAFLD) in children at the age of 7-18 years. The overall prevalence of FLD increased with age in both genders to the peak of 27.4% in the group of subjects at the age of 60-70 years. The prevalence rate was significantly higher in men than in women under the age of 50 years (22.4% vs 7.1%,P < 0.001). However,the opposite phenomenon was found over the age of 50 years (20.6% vs 27.6%,P < 0.05). Multivariate and logistic regression analysis indicated that male gender,urban residency,low education,high blood pressure,body mass index,waist circumference,waist to hip ratio,serum triglyceride and glucose levels were the risk factors for FLD. CONCLUSION: FLD,especially NAFLD,is prevalent in South China. There are many risk factors for FLD.
文摘Objective To investigate the prevalence of peripheral arterial disease (PAD) in China type 2 diabetic patients and to demonstrate the relationships between putative risk factors and PAD. Methods In total 1 397 type 2 diabetic patients aged 50 years and older were enrolled and determined ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) in 15 Class III Grade A hospitals in 7 major cities of China. Results Mean patient age was 63.7±8.2 years and mean duration of diabetes mellitus was 9.39±7.4 years. Two hundreds and seventy-two (19.47%) patients were diagnosed as PAD by ABI <0.9, 122 (18.37%) in male and 150 (20.46%) in female. PAD patients had a significantly longer duration of diabetes mellitus, higher hemoglobin Alc, and a significantly lower mean body mass index than non-PAD ones. Aging, smoking, and systolic blood pressure were found to be positively related with the prevalence of PAD. In terms of lipid profiles, no variable was found to relate with PAD. Notably, baPWV showed as the same significant guiding index for PAD, almost matched with ABI. Conclusions PAD is a common complication in China type 2 diabetic patients. Therefore, PAD screening and treatment should be emphasized for diabetic patients with high risk factors.
基金Research on Interdecadal Variation of the Progression of Subtropical Summer Monsoon inEast Asia, a specialized project of China Meteorological AdministrationResearch on Subtropical Monsoon, aspecialized project of Shanghai Meteorological Bureau
文摘Using daily NCEP/NCAR reanalysis dataset and observation rainfall data in China for the 1971-2000 period, a subtropical summer monsoon index has been defined by meridional moisture transport of the total atmosphere column. Results show that the subtropical summer monsoon index defined by the difference of meridional moisture transport between South China and North China can be used to describe the intensity of the subtropical summer monsoon. High (low) index is corresponding to strong (weak) subtropical summer monsoon. And the new index is well related to the summer rainfall over the middle and lower reaches of Yangtze River. In addition, the convergence of moisture transport from the west Pacific via the South China Sea and that from the North China may be responsible for the anomalously excessive summer rainfall over the middle and lower reaches of Yangtze River.
文摘AIM: To determine the prevalence and symptoms of gastroesophageal reflux disease (GERD) in a healthy general population in relation to demographic,lifestyle and health-seeking behaviors in Shiraz,southern Iran. METHODS: A total of 1978 subjects aged > 35 years who referred to Gastroenterohepatology Research Center and who completed a questionnaire consisting of 27 questions for GERD in relation to demographic,lifestyle and health-seeking behaviors were included in this study for a period of five months. The validity and reliability of the questionnaire were determined. RESULTS: The prevalence of GERD was 15.4%,which was higher in females (17.3%),in rural areas (19.8%),and in illiterate subjects (21.5%) and those with a mean age of 50.25 years. The prevalence was significantly lower in subjects having fried food (14.8%),and fruit and vegetables (14.6%). More symptoms were noticed in subjects consuming pickles (22.1%),taking aspirin (21%) and in subjects with psychological distresses (27.2%) and headaches (22%). The correlation was statistically significant between GERD and halitosis (18.3%),dyspepsia (30.6%),anxiety (19.5%),nightmares (23.9%) and restlessness (18.5%). Their health seeking behavior showed that there was a significant restriction of diet (20%),consumption of herbal medicine (19%),using over-the-counter drugs (29.9%) and consulting with physicians (24.8%). Presence of GERD symptoms was also significantly related to a previous family history of the disease (22.3%).CONCLUSION: GERD is more common in females,rural and illiterate subjects and correlated with consumption of pickles,occurrence of headache,psychological distress,dyspepsia,halitosis,anxiety,nightmare and restlessness,and a family history of GERD and aspirin intake,but the correlation was negative with consumption of fat and fiber intake.
基金Project (No. 50577056) supported by the National Natural Science Foundation of China
文摘This paper proposes an analysis and a direct power control (DPC) design of a wind turbine driven doubly-fed induction generator (DFIG) under unbalanced network voltage conditions. A DFIG model described in the positive and negative synchronous reference frames is presented. Variations of the stator output active and reactive powers are fully deduced in the presence of negative sequence supply voltage and rotor flux. An enhanced DPC scheme is proposed to eliminate stator active power oscillation during network unbalance. The proposed control scheme removes rotor current regulators and the decomposition processing of positive and negative sequence rotor currents. Simulation results using PSCAD/EMTDC are presented on a 2-MW DFIG wind power generation system to validate the feasibility of the proposed control scheme under balanced and unbalanced network conditions.
