The gas-liquid two-phase swirl flow can increase the gas-liquid two-phase contact area and enhance the heat and mass transfer efficiency between gas and liquid.The swirl flow has important practical application value ...The gas-liquid two-phase swirl flow can increase the gas-liquid two-phase contact area and enhance the heat and mass transfer efficiency between gas and liquid.The swirl flow has important practical application value for promoting gas hydrate formation and ensuring the flow safe of natural gas hydrate slurry.The experimental section was made of plexiglass pipe and the experimental medium was air and water.The flow pattern of the gas-liquid two-phase swirl flow in the horizontal pipe was divided,according to a high-definition camera and the overall characteristics of the gas-liquid interface.The flow pattern map of the gas-liquid two-phase swirl flow in a horizontal pipe was studied.The influence of the flow velocity and vane parameters on pressure drop was investigated.Two types of gas-liquid two-phase swirl flow pressure drop models was established.The homogeneous-phase and split-phase pressure drop models have good prediction on swirl bubble flow,swirl dispersed flow,swirl annular flow and swirl stratified flow,and the predictive error band is not more than 20%.展开更多
Backgroud Numerous studies have confirmed the effectiveness of slowing the progression of atherosclerosis by blood pressure （Bp） control in patients with hypertension and several studies also showed the efficacy of ...Backgroud Numerous studies have confirmed the effectiveness of slowing the progression of atherosclerosis by blood pressure （Bp） control in patients with hypertension and several studies also showed the efficacy of intensive glycemic control in decreasing progression of carotid intima-media thickness （CIMT） in patients with type 1 and type 2 diabetes. However, few studies have compared the relative importance of glycemic w＇. Bp control in patients with diabetes and hypertension. We aimed to investigate the association between Bp and glycemic control and subclinical carotid atherosclerosis in older patients with hypertension and type 2 diabetes. Methods In a cross-sectional study, B-mode high-resolution ultrasonography of the carotid artery was performed in 670 subjects （508 males and 162 females） aged 60 years or over who had self-reported hypertension and diabetes but no history of coronary heart disease or stroke. Subjects were categorized by their systolic blood pressure： tight control, 〈 130 mmHg; usual control, 130-139 mmHg; or uncontrolled, 〉 140 mmHg, and by their hemoglobin Alc （HbAlc） level： tight control, 〈 6.5%; usual control, 6.5%-7.5%; or uncontrolled, 〉 7.5%, respectively. Results The mean CIMT was 8.20 ±0.11 mm, and carotid plaque was found in 52.5% （352/670） subjects. Overall, 62.1% of the subjects had subclinical carotid atherosclerosis, defined as having either carotid plaque or elevated CIMT （≥ 1.1 ram）. The mean CIMT was significantly different between Bp control categories （7.60 ± 0.09 mm, 7.90 ±0.08 mm, and 8.60 ± 0.12 mm, respectively, P = 0.03） but not between glycemic control categories （8.20± 0.10 mm, 8.1 ±0.08 mm, and 8.40 ± 0.14 ram, respectively, P = 0.13） using ANCOVA analysis. Multivariable logistic regression adjusting for potential confounding factors showed that usual or uncontrolled Bp control were associated with having carotid plaque （OR = 1.08 and OR=1.42, respectively）, or elevated CIMT [Odd ratio （OR） = 1.17, 95% confidence interval （CI） 1.04-2.24, and OR = 1.54, 95% CI 1.36-2.96, respectively compared to tight Bp control; but did not show glycemic control as independent predictor of either having carotid plaque or elevated CIMT. Conclusions In older patients with hypertension and diabetes, blood pressure control, but not glycemic control is associated with subclinical carotid atherosclerosis.展开更多
AIM:To study the blood-brain barrier integrity,brain edema, animal behavior and ammonia plasma levels in prehepatic portal hypertensive rats with and without acute liver intoxication. METHODS:Adults male Wistar rats w...AIM:To study the blood-brain barrier integrity,brain edema, animal behavior and ammonia plasma levels in prehepatic portal hypertensive rats with and without acute liver intoxication. METHODS:Adults male Wistar rats were divided into four groups.Group Ⅰ:sham operation;Ⅱ:Prehepatic portal hypertension,produced by partial portal vein ligation;Ⅲ: Acetaminophen intoxication and Ⅳ:Prehepatic portal hypertension plus acetaminophen.Acetaminophen was administered to produce acute hepatic injury.Portal pressure,liver serum enzymes and ammonia plasma levels were determined.Brain cortex water content was registered and trypan blue was utilized to study blood brain barrier integrity.Reflexes and behavioral tests were recorded. RESULTS:Portal hypertension was significantly elevated in groups Ⅱ and Ⅳ.Uver enzymes and ammonia plasma levels were increased in groups Ⅱ,Ⅲ and Ⅳ.Prehepatic portal hypertension (group Ⅱ),acetaminophen intoxication (group Ⅲ) and both (group Ⅳ) had changes in the blood brain-barrier integrity (trypan blue) and hyperammonemia.Cortical edema was present in rats with acute hepatic injury in groups Ⅲ and Ⅳ.Behavioral test (rota rod) was altered in group Ⅳ. CONCLUSION:These results suggest the possibility of another pathway for cortical edema production because blood brain barrier was altered (vasogenic) and hyperammonemia was registered (oltotoxic).Group Ⅳ,with behavioral altered test,can be considered as a model for study at an early stage of portal-systemic encephalopathy.展开更多
To the Editor I read the article of Zhang, et al. with great interest. They investigated the association of homocysteine with arterial stiffness in Chinese community-based elderly persons. The carotid-femoral pulse wa...To the Editor I read the article of Zhang, et al. with great interest. They investigated the association of homocysteine with arterial stiffness in Chinese community-based elderly persons. The carotid-femoral pulse wave velocity （PWV） was significantly higher in the high homocyteine group than in the normal one, however, there was no differences in carotid-radial PWV between the high homocyteine group and the normal one. Homocysteine levels were strongly associated with the carotidfemoral PWV even after adjustment for classical risk factors of cardiovascular disease. I congratulate the authors for this important study. However, I want to make minor criticism for this study from the methodological aspect.展开更多
基金Project(51574045)supported by the National Nature Science Foundation of China
文摘The gas-liquid two-phase swirl flow can increase the gas-liquid two-phase contact area and enhance the heat and mass transfer efficiency between gas and liquid.The swirl flow has important practical application value for promoting gas hydrate formation and ensuring the flow safe of natural gas hydrate slurry.The experimental section was made of plexiglass pipe and the experimental medium was air and water.The flow pattern of the gas-liquid two-phase swirl flow in the horizontal pipe was divided,according to a high-definition camera and the overall characteristics of the gas-liquid interface.The flow pattern map of the gas-liquid two-phase swirl flow in a horizontal pipe was studied.The influence of the flow velocity and vane parameters on pressure drop was investigated.Two types of gas-liquid two-phase swirl flow pressure drop models was established.The homogeneous-phase and split-phase pressure drop models have good prediction on swirl bubble flow,swirl dispersed flow,swirl annular flow and swirl stratified flow,and the predictive error band is not more than 20%.
基金Acknowledgment This research was supported in part by the National Natural Science Foundation of China （81072355）, Beijing Medical Scientific Development Foundation （2007-2039）, Ministry of Science and Technology of China （2009BAI 86B01）.
文摘Backgroud Numerous studies have confirmed the effectiveness of slowing the progression of atherosclerosis by blood pressure （Bp） control in patients with hypertension and several studies also showed the efficacy of intensive glycemic control in decreasing progression of carotid intima-media thickness （CIMT） in patients with type 1 and type 2 diabetes. However, few studies have compared the relative importance of glycemic w＇. Bp control in patients with diabetes and hypertension. We aimed to investigate the association between Bp and glycemic control and subclinical carotid atherosclerosis in older patients with hypertension and type 2 diabetes. Methods In a cross-sectional study, B-mode high-resolution ultrasonography of the carotid artery was performed in 670 subjects （508 males and 162 females） aged 60 years or over who had self-reported hypertension and diabetes but no history of coronary heart disease or stroke. Subjects were categorized by their systolic blood pressure： tight control, 〈 130 mmHg; usual control, 130-139 mmHg; or uncontrolled, 〉 140 mmHg, and by their hemoglobin Alc （HbAlc） level： tight control, 〈 6.5%; usual control, 6.5%-7.5%; or uncontrolled, 〉 7.5%, respectively. Results The mean CIMT was 8.20 ±0.11 mm, and carotid plaque was found in 52.5% （352/670） subjects. Overall, 62.1% of the subjects had subclinical carotid atherosclerosis, defined as having either carotid plaque or elevated CIMT （≥ 1.1 ram）. The mean CIMT was significantly different between Bp control categories （7.60 ± 0.09 mm, 7.90 ±0.08 mm, and 8.60 ± 0.12 mm, respectively, P = 0.03） but not between glycemic control categories （8.20± 0.10 mm, 8.1 ±0.08 mm, and 8.40 ± 0.14 ram, respectively, P = 0.13） using ANCOVA analysis. Multivariable logistic regression adjusting for potential confounding factors showed that usual or uncontrolled Bp control were associated with having carotid plaque （OR = 1.08 and OR=1.42, respectively）, or elevated CIMT [Odd ratio （OR） = 1.17, 95% confidence interval （CI） 1.04-2.24, and OR = 1.54, 95% CI 1.36-2.96, respectively compared to tight Bp control; but did not show glycemic control as independent predictor of either having carotid plaque or elevated CIMT. Conclusions In older patients with hypertension and diabetes, blood pressure control, but not glycemic control is associated with subclinical carotid atherosclerosis.
基金Supported by Grant #TB 56 from the University of Buenos Aires,Argentina
文摘AIM:To study the blood-brain barrier integrity,brain edema, animal behavior and ammonia plasma levels in prehepatic portal hypertensive rats with and without acute liver intoxication. METHODS:Adults male Wistar rats were divided into four groups.Group Ⅰ:sham operation;Ⅱ:Prehepatic portal hypertension,produced by partial portal vein ligation;Ⅲ: Acetaminophen intoxication and Ⅳ:Prehepatic portal hypertension plus acetaminophen.Acetaminophen was administered to produce acute hepatic injury.Portal pressure,liver serum enzymes and ammonia plasma levels were determined.Brain cortex water content was registered and trypan blue was utilized to study blood brain barrier integrity.Reflexes and behavioral tests were recorded. RESULTS:Portal hypertension was significantly elevated in groups Ⅱ and Ⅳ.Uver enzymes and ammonia plasma levels were increased in groups Ⅱ,Ⅲ and Ⅳ.Prehepatic portal hypertension (group Ⅱ),acetaminophen intoxication (group Ⅲ) and both (group Ⅳ) had changes in the blood brain-barrier integrity (trypan blue) and hyperammonemia.Cortical edema was present in rats with acute hepatic injury in groups Ⅲ and Ⅳ.Behavioral test (rota rod) was altered in group Ⅳ. CONCLUSION:These results suggest the possibility of another pathway for cortical edema production because blood brain barrier was altered (vasogenic) and hyperammonemia was registered (oltotoxic).Group Ⅳ,with behavioral altered test,can be considered as a model for study at an early stage of portal-systemic encephalopathy.
文摘To the Editor I read the article of Zhang, et al. with great interest. They investigated the association of homocysteine with arterial stiffness in Chinese community-based elderly persons. The carotid-femoral pulse wave velocity （PWV） was significantly higher in the high homocyteine group than in the normal one, however, there was no differences in carotid-radial PWV between the high homocyteine group and the normal one. Homocysteine levels were strongly associated with the carotidfemoral PWV even after adjustment for classical risk factors of cardiovascular disease. I congratulate the authors for this important study. However, I want to make minor criticism for this study from the methodological aspect.
