目的评估成年患者经外周置入中心静脉导管(peripherally inserted central catheter,PICC)的最佳长度和身高的相关性以及PICC尖端位置异常的发生率。方法回顾性分析2008-2011年200例20岁以上行PICC置管的患者,按照身高分为3组:A组150～1...目的评估成年患者经外周置入中心静脉导管(peripherally inserted central catheter,PICC)的最佳长度和身高的相关性以及PICC尖端位置异常的发生率。方法回顾性分析2008-2011年200例20岁以上行PICC置管的患者,按照身高分为3组:A组150～160cm;B组161～170cm;C组171～180cm。根据后前位X线胸片比较3组患者左右臂PICC导管的插入长度及尖端位置。结果 3组间左、右两侧PICC置管长度差异均有统计学意义(P<0.01),各组内左、右两侧的插入长度差异也有统计学意义(P<0.05)。3组患者导管最佳位置的比例差异无统计学意义(P>0.05),左右臂导管最佳位置及位点异常的比例差异无统计学意义(P>0.05),但右臂导管走行异常的发生率高于左臂(P<0.05)。结论在PICC置管时,应根据患者身高及左右侧选择适宜的置管长度,当选择右臂置管时应注意防止导管走行异位。展开更多
A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dyna...A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dynamic mechanical model for the sarcomere in skeletal muscle. This model has been solved with a numerical algorithm based on experimental chemical transition rates. The influences of ATP concentration and load on probability density, contraction velocity and maximum active force are discussed respectively. It is shown that contraction velocity and maximum isometric active force increase with the increasing ATP concentration and become constant when the ATP concentration reaches equilibrium saturation. Contraction velocity reduces gradually as the load force increases. We also find that active force begins to increase then decrease with the increasing length of sarcomere, and has a maximum value at the optimal length that all myosin motors can attach to actin filament. Our results are in good agreement with the Hill muscle model.展开更多
It has been known for some time that strain injuries occur through the excessive lengthening of a muscle.^(1–3)However,the precise mechanism for strain injury remains elusive and has been the subject of recent debate...It has been known for some time that strain injuries occur through the excessive lengthening of a muscle.^(1–3)However,the precise mechanism for strain injury remains elusive and has been the subject of recent debate in the Journal of Sport and Health Science,^(4–9)but it seems sensible to consider mechanisms at the level of the muscle fiber.It was previously believed that damage was the result of non-uniform stretching of展开更多
文摘目的评估成年患者经外周置入中心静脉导管(peripherally inserted central catheter,PICC)的最佳长度和身高的相关性以及PICC尖端位置异常的发生率。方法回顾性分析2008-2011年200例20岁以上行PICC置管的患者,按照身高分为3组:A组150～160cm;B组161～170cm;C组171～180cm。根据后前位X线胸片比较3组患者左右臂PICC导管的插入长度及尖端位置。结果 3组间左、右两侧PICC置管长度差异均有统计学意义(P<0.01),各组内左、右两侧的插入长度差异也有统计学意义(P<0.05)。3组患者导管最佳位置的比例差异无统计学意义(P>0.05),左右臂导管最佳位置及位点异常的比例差异无统计学意义(P>0.05),但右臂导管走行异常的发生率高于左臂(P<0.05)。结论在PICC置管时,应根据患者身高及左右侧选择适宜的置管长度,当选择右臂置管时应注意防止导管走行异位。
基金supported by the National Natural Science Foundation of China (Grant No. 61075101/60643002)the Research Fund of State Key Laboratory of MSV, China (Grant No. MSV-2010-1)+2 种基金the National High-Tech Research and Development Program of China (Grant No. 2006AA04Z240)the Shanghai Dawn Program (Grant No. 07SG14)the Medical and Technology Intercrossing Research Foundation of Shanghai Jiao Tong University (Grant No. YG2010ZD101)
文摘A non-equilibrium statistical method is used to study the collective characteristics of myosin II motors in a sarcomere during its contraction. By means of Fokker-Planck equation of molecular motors, we present a dynamic mechanical model for the sarcomere in skeletal muscle. This model has been solved with a numerical algorithm based on experimental chemical transition rates. The influences of ATP concentration and load on probability density, contraction velocity and maximum active force are discussed respectively. It is shown that contraction velocity and maximum isometric active force increase with the increasing ATP concentration and become constant when the ATP concentration reaches equilibrium saturation. Contraction velocity reduces gradually as the load force increases. We also find that active force begins to increase then decrease with the increasing length of sarcomere, and has a maximum value at the optimal length that all myosin motors can attach to actin filament. Our results are in good agreement with the Hill muscle model.
文摘It has been known for some time that strain injuries occur through the excessive lengthening of a muscle.^(1–3)However,the precise mechanism for strain injury remains elusive and has been the subject of recent debate in the Journal of Sport and Health Science,^(4–9)but it seems sensible to consider mechanisms at the level of the muscle fiber.It was previously believed that damage was the result of non-uniform stretching of
