A conveyor belt driven by wound rotor motors produces dynamic tension, velocity and accelerationduring starting. The terrible situation (such as resonance) in dynamic analysis and design is that system naturalfrequenc...A conveyor belt driven by wound rotor motors produces dynamic tension, velocity and accelerationduring starting. The terrible situation (such as resonance) in dynamic analysis and design is that system naturalfrequencies are equal to those for switching off electric resistances. This paper analyzes and determines systemnatural frequencies based on a modeling method of receptances with the analysis of sub-systems model and of theprinciple of their addition and conveyor loop closure. It also puts forward to calculate the time interval for switching off electric resistances. The starting of one conveyor is simulated by lumped-mass-spring-model software tofurther illustrate the influence of time interval for switching off electric resistances on conveyor dynamic behavior. Two methods are also compared. The receptance model is proved to be an excellent alternative.展开更多
Background Pulmonary veins （PV） and the atria undergo electrical and structural remodeling in atrial fibrillation （AF）. This study aimed to determine PV and left atrial （LA） reverse remodeling after catheter abl...Background Pulmonary veins （PV） and the atria undergo electrical and structural remodeling in atrial fibrillation （AF）. This study aimed to determine PV and left atrial （LA） reverse remodeling after catheter ablation for AF assessed by chest computed tomography （CT）. Methods PV electrophysiologic studies and catheter ablation were performed in 63 patients （68% male; mean ± SD age： 56 ± 10 years） with symptomatic AF （49% paroxysmal, 51% persistent）. Chest CT was performed before and 3 months after catheter ablation. Results At baseline, patients with persistent AF had a greater LA volume （91 ±29 cm3 vs. 66 ± 27 cm3; P = 0.003） and mean PV ostial area （241 ＋ 43 mm2 vs. 212 ± 47 mm2; P = 0.03） than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients （76%） were AF free on or off antiarrhythmic drugs. There was a significant reduction in LA volume （77 ±31 cm3 to 70 ± 28 cm3; P 〈 0.001） and mean PV ostial area （224 ± 48 mm2 to 182 ± 43 mm2; P 〈 0.001）. Patients with persistent AF had more reduction in LA volume （11.8 ± 12.8 cm3 vs. 4.0 ± 11.2 cm3; P = 0.04） and PV ostial area （62 mm2 vs. 34 mm2; P = 0.04） than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume （r = 0.38, P = 0.03）. Conclusions Catheter ablation of AF improves structural remodeling ofPV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.展开更多
Arthropod community structure and diversity were investigated in transgenic insect-resistant hybrid poplar 741 field trial plots, which had five isogenic clones with two genes （Bt. toxin [Cry IAc] and arrowhead prote...Arthropod community structure and diversity were investigated in transgenic insect-resistant hybrid poplar 741 field trial plots, which had five isogenic clones with two genes （Bt. toxin [Cry IAc] and arrowhead proteinase inhibitor [API]） in comparison to control plots. Transgenic poplar clones were investigated according to their insect resistance （high and medium resistant clones）, being systematically probed into varying levels with feeding tests before. Investigations were carded out during three years （2002, 2003 and 2005）. The results indicated that among the basal species, transgenic plants in general had lower amounts of phytophagous insects, and an increased quantity of neutral arthropods such as saprophytic and strolling species. Among the top and intermediate species in transgenic variants, the quantity of predatory natural enemies was increased, while the amount of parasitoid ones was slightly reduced. The arthropod community characteristic indices were analyzed from different aspects in the three variants. It was discovered that, not only the characteristic indices of the whole arthropod community, but also the characteristic indices of the sub-communities （such as natural enemy, pest and neutral arthropods） and the functional groups categorized by their feeding patterns, showed a higher diversity and evenness and a lower dominancy concentration indices in the high-resistant and medium-resistant plots compared with the control. Transgenic poplar 741 showed improved ecological effects both in partial and total aspects. It could be concluded that composition and structure of the arthropod community in plots with transgenic insect-resistant poplar were turned to be more reasonable and itsdiversity and stability was enhanced.展开更多
By monitoring the time evolution of the optical absorption spectrum corresponding to dy- namic information of aspect ratio （AR） and volume, we succeeded in following the growth kinetics of gold nanorods. The results...By monitoring the time evolution of the optical absorption spectrum corresponding to dy- namic information of aspect ratio （AR） and volume, we succeeded in following the growth kinetics of gold nanorods. The results indicate that the rods growth consists of two stages： seeds develop into rods with a fast AR increase and the rods grow big with constant AR. Here, a charge transfer model, involving positive charge transfer from Au（I） to seed and neu- tralization by electron from ascorbic acid, has been introduced to explain the autoeatalysis mechanism of rod growth. The good agreement between the numerical simulation based on this moldel and experimental results supports the proposed mechanism.展开更多
OBJECTIVE:To evaluate the protection of Danshen{Radix Salviae Miltiorrhizae)(SM) injection in myocardial infarction(Ml) induced renal damage.METHODS:Forty male C57 mice were divided into control group,Ml group and SM ...OBJECTIVE:To evaluate the protection of Danshen{Radix Salviae Miltiorrhizae)(SM) injection in myocardial infarction(Ml) induced renal damage.METHODS:Forty male C57 mice were divided into control group,Ml group and SM group.In Ml group,the left coronary artery was occluded for 8weeks;the same procedure was used for the SM group,with the additional step of SM(0.2 mL) administered intraperitoneally for 56 days.Before surgery and 8 weeks later,transthoracic echocardiography was performed and urine protein and albumin was measured.At the end of the time,all mice were killed and kidneys removed for reactive oxygen species(ROS) and fibrosis analysis,plasma was collected for blood urea nitrogen and serum creatinine determination.RESULTS:Ml slightly decreased renal function and increased production of ROS,accompanied with renal fibrosis.Administration of SM reduced production of ROS and increased renal function,it also reduced renal fibrosis.CONCLUSION:Ml plays a causal role in renal injury and SM exerts renal-protective effects,probably by its antioxidant activities.展开更多
文摘A conveyor belt driven by wound rotor motors produces dynamic tension, velocity and accelerationduring starting. The terrible situation (such as resonance) in dynamic analysis and design is that system naturalfrequencies are equal to those for switching off electric resistances. This paper analyzes and determines systemnatural frequencies based on a modeling method of receptances with the analysis of sub-systems model and of theprinciple of their addition and conveyor loop closure. It also puts forward to calculate the time interval for switching off electric resistances. The starting of one conveyor is simulated by lumped-mass-spring-model software tofurther illustrate the influence of time interval for switching off electric resistances on conveyor dynamic behavior. Two methods are also compared. The receptance model is proved to be an excellent alternative.
文摘Background Pulmonary veins （PV） and the atria undergo electrical and structural remodeling in atrial fibrillation （AF）. This study aimed to determine PV and left atrial （LA） reverse remodeling after catheter ablation for AF assessed by chest computed tomography （CT）. Methods PV electrophysiologic studies and catheter ablation were performed in 63 patients （68% male; mean ± SD age： 56 ± 10 years） with symptomatic AF （49% paroxysmal, 51% persistent）. Chest CT was performed before and 3 months after catheter ablation. Results At baseline, patients with persistent AF had a greater LA volume （91 ±29 cm3 vs. 66 ± 27 cm3; P = 0.003） and mean PV ostial area （241 ＋ 43 mm2 vs. 212 ± 47 mm2; P = 0.03） than patients with paroxysmal AF. There was no significant correlation between the effective refractory period and the area of the left superior PV ostium. At 3 months of follow-up after ablation, 48 patients （76%） were AF free on or off antiarrhythmic drugs. There was a significant reduction in LA volume （77 ±31 cm3 to 70 ± 28 cm3; P 〈 0.001） and mean PV ostial area （224 ± 48 mm2 to 182 ± 43 mm2; P 〈 0.001）. Patients with persistent AF had more reduction in LA volume （11.8 ± 12.8 cm3 vs. 4.0 ± 11.2 cm3; P = 0.04） and PV ostial area （62 mm2 vs. 34 mm2; P = 0.04） than those who have paroxysmal AF. The reduction of the averaged PV ostial area was significantly correlated with the reduction of LA volume （r = 0.38, P = 0.03）. Conclusions Catheter ablation of AF improves structural remodeling ofPV ostia and left atrium. This finding is more apparent in patients with persistent AF treated by catheter ablation.
文摘Arthropod community structure and diversity were investigated in transgenic insect-resistant hybrid poplar 741 field trial plots, which had five isogenic clones with two genes （Bt. toxin [Cry IAc] and arrowhead proteinase inhibitor [API]） in comparison to control plots. Transgenic poplar clones were investigated according to their insect resistance （high and medium resistant clones）, being systematically probed into varying levels with feeding tests before. Investigations were carded out during three years （2002, 2003 and 2005）. The results indicated that among the basal species, transgenic plants in general had lower amounts of phytophagous insects, and an increased quantity of neutral arthropods such as saprophytic and strolling species. Among the top and intermediate species in transgenic variants, the quantity of predatory natural enemies was increased, while the amount of parasitoid ones was slightly reduced. The arthropod community characteristic indices were analyzed from different aspects in the three variants. It was discovered that, not only the characteristic indices of the whole arthropod community, but also the characteristic indices of the sub-communities （such as natural enemy, pest and neutral arthropods） and the functional groups categorized by their feeding patterns, showed a higher diversity and evenness and a lower dominancy concentration indices in the high-resistant and medium-resistant plots compared with the control. Transgenic poplar 741 showed improved ecological effects both in partial and total aspects. It could be concluded that composition and structure of the arthropod community in plots with transgenic insect-resistant poplar were turned to be more reasonable and itsdiversity and stability was enhanced.
文摘By monitoring the time evolution of the optical absorption spectrum corresponding to dy- namic information of aspect ratio （AR） and volume, we succeeded in following the growth kinetics of gold nanorods. The results indicate that the rods growth consists of two stages： seeds develop into rods with a fast AR increase and the rods grow big with constant AR. Here, a charge transfer model, involving positive charge transfer from Au（I） to seed and neu- tralization by electron from ascorbic acid, has been introduced to explain the autoeatalysis mechanism of rod growth. The good agreement between the numerical simulation based on this moldel and experimental results supports the proposed mechanism.
基金the Grants from the National Natural Science Foundation of China(Effects of Membrane-type Matrix Metalloproteinase 1 on Vascular Endothelial Cell Proliferation and Differentiation,No.81100109)
文摘OBJECTIVE:To evaluate the protection of Danshen{Radix Salviae Miltiorrhizae)(SM) injection in myocardial infarction(Ml) induced renal damage.METHODS:Forty male C57 mice were divided into control group,Ml group and SM group.In Ml group,the left coronary artery was occluded for 8weeks;the same procedure was used for the SM group,with the additional step of SM(0.2 mL) administered intraperitoneally for 56 days.Before surgery and 8 weeks later,transthoracic echocardiography was performed and urine protein and albumin was measured.At the end of the time,all mice were killed and kidneys removed for reactive oxygen species(ROS) and fibrosis analysis,plasma was collected for blood urea nitrogen and serum creatinine determination.RESULTS:Ml slightly decreased renal function and increased production of ROS,accompanied with renal fibrosis.Administration of SM reduced production of ROS and increased renal function,it also reduced renal fibrosis.CONCLUSION:Ml plays a causal role in renal injury and SM exerts renal-protective effects,probably by its antioxidant activities.
