Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force Is helpful for experiment...Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force Is helpful for experimental work. The aim of this study was to numerically investigate the stress distribution of the cell wall, cell turgor, and deformation of plant cells in response to applied poking force. Furthermore, the locations damaged during poking were analyzed. The model simulates cell poking, with the cell treated as a spherical, homogeneous, isotropic elastic membrane, filled with incompressible, highly viscous liquid. Equilibrium equations for the contact region and the non-contact regions were determined by using membrane theory. The boundary conditions and continuity conditions for the solution of the problem were found. The forcedeformation curve, turgor pressure and tension of the cell wall under cell poking conditions were obtained. The tension of the cell wall circumference was larger than that of the meridian. In general, maximal stress occurred at the equator around. When cell deformation increased to a certain level, the tension at the poker tip exceeded that of the equator. Breakage of the cell wall may start from the equator or the poker tip, depending on the deformation. A nonlinear model is suitable for estimating turgor, stress, and stiffness, and numerical simulation is a powerful method for determining plant cell mechanical properties.展开更多
Purpose： To compare the efficacy of percutaneous poking reduction and fixation with open reduction and fixation in the treatment of displaced calcaneal fractures. Methods： Reports of studies using case-controlled tr...Purpose： To compare the efficacy of percutaneous poking reduction and fixation with open reduction and fixation in the treatment of displaced calcaneal fractures. Methods： Reports of studies using case-controlled trials （CCT） to compare the percutaneous poking reduction and fixation with the open reduction and fixation in the management of calcaneal fractures were retrieved from the Cochrane Library, PubMed Database, CNKI, Chinese Biomedical Database, Wanfang Data （fromJanuary of 2005 to August of 2015）. Methodological quality of the trials was critically assessed, and relevant data were extracted. Statistical software Revman 5.0 was used for data-analysis. Results： Fifteen articles were included in the meta-analysis. Comparison of the efficacy of percutaneous poking reduction and fixation with open reduction and fixation in the treatment of calcaneal fractures revealed statistical significance in the incidence of complications after operation [RR -- 0.32, 95,~ Cl （0.20, 0.5）, p 〈 0.05]. However, there were neither statistical significance in the degrees of recovery for calcaneal Bohler angle [WMD = -1.65, 95% CI （ 3.43, 0.14）, p 〉 0.05] and calcaneal Gissane angle [WMD - -3.21, 95%, Cl （-6.75, 0.33）, p 〉 0.05], nor statistical significance in the rate of good foot function after operation [RR = 0.95, 95Z Cl （0.90, 1.00）, p 〉 0.05]. Conclusion： For the treatment of calcaneal fractures, percutaneous poking reduction and fixation is superior to open reduction and fixation in terms of the incidence of postoperative complications. But both techniques can obtain satisfactory clinical function.展开更多
基金Supported by the National Natural Science Foundation of China(10472132)
文摘Cell poking is an experimental technique that is widely used to study the mechanical properties of plant cells. A full understanding of the mechanical responses of plant cells to poking force Is helpful for experimental work. The aim of this study was to numerically investigate the stress distribution of the cell wall, cell turgor, and deformation of plant cells in response to applied poking force. Furthermore, the locations damaged during poking were analyzed. The model simulates cell poking, with the cell treated as a spherical, homogeneous, isotropic elastic membrane, filled with incompressible, highly viscous liquid. Equilibrium equations for the contact region and the non-contact regions were determined by using membrane theory. The boundary conditions and continuity conditions for the solution of the problem were found. The forcedeformation curve, turgor pressure and tension of the cell wall under cell poking conditions were obtained. The tension of the cell wall circumference was larger than that of the meridian. In general, maximal stress occurred at the equator around. When cell deformation increased to a certain level, the tension at the poker tip exceeded that of the equator. Breakage of the cell wall may start from the equator or the poker tip, depending on the deformation. A nonlinear model is suitable for estimating turgor, stress, and stiffness, and numerical simulation is a powerful method for determining plant cell mechanical properties.
基金This study was funded by the National Natural Science Foundation of China （No. 81572098）.
文摘Purpose： To compare the efficacy of percutaneous poking reduction and fixation with open reduction and fixation in the treatment of displaced calcaneal fractures. Methods： Reports of studies using case-controlled trials （CCT） to compare the percutaneous poking reduction and fixation with the open reduction and fixation in the management of calcaneal fractures were retrieved from the Cochrane Library, PubMed Database, CNKI, Chinese Biomedical Database, Wanfang Data （fromJanuary of 2005 to August of 2015）. Methodological quality of the trials was critically assessed, and relevant data were extracted. Statistical software Revman 5.0 was used for data-analysis. Results： Fifteen articles were included in the meta-analysis. Comparison of the efficacy of percutaneous poking reduction and fixation with open reduction and fixation in the treatment of calcaneal fractures revealed statistical significance in the incidence of complications after operation [RR -- 0.32, 95,~ Cl （0.20, 0.5）, p 〈 0.05]. However, there were neither statistical significance in the degrees of recovery for calcaneal Bohler angle [WMD = -1.65, 95% CI （ 3.43, 0.14）, p 〉 0.05] and calcaneal Gissane angle [WMD - -3.21, 95%, Cl （-6.75, 0.33）, p 〉 0.05], nor statistical significance in the rate of good foot function after operation [RR = 0.95, 95Z Cl （0.90, 1.00）, p 〉 0.05]. Conclusion： For the treatment of calcaneal fractures, percutaneous poking reduction and fixation is superior to open reduction and fixation in terms of the incidence of postoperative complications. But both techniques can obtain satisfactory clinical function.
