As a classical topic,the hydrodynamic forces on a submerged horizontal cylinder undergoing forced oscillation have been widely studied based on potential flow theory.However,the fluid viscosity and the flow rotation m...As a classical topic,the hydrodynamic forces on a submerged horizontal cylinder undergoing forced oscillation have been widely studied based on potential flow theory.However,the fluid viscosity and the flow rotation may play an important role when the oscillation amplitude of the circular cylinder is large,and large discrepancy will occur between the potential flow simulation and the experimental results.This study focuses on the study of hydrodynamic forces on a submerged horizontal circular cylinder undergoing forced oscillation by means of a viscous fluid numerical wave tank(NWT)model.The accuracy of the numerical model is validated against available experimental data.The comparisons between the hydrodynamic forces on the circular cylinder predicted by the viscous fluid model and the potential flow model are conducted to show the viscous effects on the hydrodynamic forces.By the study on the flow fields,the mechanism of the viscous effects is explained by the vortex effect.The basic reason for the difference between the results based on the viscous fluid theory and the potential flow theory is revealed by analyzing the force components.展开更多
To the Editor:Data from the Global Observatory on Donation and Transplantation (GODT) indicate that of the 126,670 solid organs reported to be transplanted in 2015, kidneys made up 66% of these organs.
The signaling pathway for tumor necrosis factor-a （TNF-a） and its receptors is up-regulated during ex- tracorporeal circulation （ECC）, and recruits blood neutrophil into the lung tissue, which results in acute lun...The signaling pathway for tumor necrosis factor-a （TNF-a） and its receptors is up-regulated during ex- tracorporeal circulation （ECC）, and recruits blood neutrophil into the lung tissue, which results in acute lung injury （ALl） In this study, we evaluated the role of tumor necrosis factor receptor I （TNFR1） in ECC-induced ALl by blocking TNF-a binding to TNFR1 with CAY10500. Anesthetized Sprague-Dawley （SD） rats were pretreated intravenously with phos- phate buffered saline （PBS） or vehicle （0.3 ml ethanol IV） or CAY10500, and then underwent ECC for 2 h. The oxy- genation index （OI） and pulmonary inflammation were assessed after ECC. OI was significantly decreased, while TNF-a and neutrophil in bronchoalveolar lavage fluid （BALF） and plasma TNF-a increased after ECC. Pretreatment of CAY10500 decreased plasma TNF-a level, but did not decrease TNF-a levels and neutrophil counts in BALF or improve OI. Lung histopathology showed significant alveolar congestion, infiltration of the leukocytes in the airspace, and increased thickness of the alveolar wall in all ECC-treated groups. CAY10500 pretreatment slightly reduced leukocyte infiltration in lungs, but did not change the wet/dry ratio in the lung tissue. Blocking TNF-a binding to TNFR1 by CAY10500 intravenously slightly mitigates pulmonary inflammation, but cannot improve the pulmonary function, indicating the limited role of TNFR1 pathway in circulating inflammatory cell in ECC-induced ALl.展开更多
基金Project supported by the Natural Science Foundation of China(Grant Nos.51490672,51761135011,51679036 and 51709038).
文摘As a classical topic,the hydrodynamic forces on a submerged horizontal cylinder undergoing forced oscillation have been widely studied based on potential flow theory.However,the fluid viscosity and the flow rotation may play an important role when the oscillation amplitude of the circular cylinder is large,and large discrepancy will occur between the potential flow simulation and the experimental results.This study focuses on the study of hydrodynamic forces on a submerged horizontal circular cylinder undergoing forced oscillation by means of a viscous fluid numerical wave tank(NWT)model.The accuracy of the numerical model is validated against available experimental data.The comparisons between the hydrodynamic forces on the circular cylinder predicted by the viscous fluid model and the potential flow model are conducted to show the viscous effects on the hydrodynamic forces.By the study on the flow fields,the mechanism of the viscous effects is explained by the vortex effect.The basic reason for the difference between the results based on the viscous fluid theory and the potential flow theory is revealed by analyzing the force components.
文摘To the Editor:Data from the Global Observatory on Donation and Transplantation (GODT) indicate that of the 126,670 solid organs reported to be transplanted in 2015, kidneys made up 66% of these organs.
基金Project supported by the National Natural Science Foundation of China （No. 81171651） and the Science and Technology Breakthrough Project of the Science and Technology Department of Sichuan Province （No. 2010FZ0044）, China
文摘The signaling pathway for tumor necrosis factor-a （TNF-a） and its receptors is up-regulated during ex- tracorporeal circulation （ECC）, and recruits blood neutrophil into the lung tissue, which results in acute lung injury （ALl） In this study, we evaluated the role of tumor necrosis factor receptor I （TNFR1） in ECC-induced ALl by blocking TNF-a binding to TNFR1 with CAY10500. Anesthetized Sprague-Dawley （SD） rats were pretreated intravenously with phos- phate buffered saline （PBS） or vehicle （0.3 ml ethanol IV） or CAY10500, and then underwent ECC for 2 h. The oxy- genation index （OI） and pulmonary inflammation were assessed after ECC. OI was significantly decreased, while TNF-a and neutrophil in bronchoalveolar lavage fluid （BALF） and plasma TNF-a increased after ECC. Pretreatment of CAY10500 decreased plasma TNF-a level, but did not decrease TNF-a levels and neutrophil counts in BALF or improve OI. Lung histopathology showed significant alveolar congestion, infiltration of the leukocytes in the airspace, and increased thickness of the alveolar wall in all ECC-treated groups. CAY10500 pretreatment slightly reduced leukocyte infiltration in lungs, but did not change the wet/dry ratio in the lung tissue. Blocking TNF-a binding to TNFR1 by CAY10500 intravenously slightly mitigates pulmonary inflammation, but cannot improve the pulmonary function, indicating the limited role of TNFR1 pathway in circulating inflammatory cell in ECC-induced ALl.
