We present an experimental method for in-situ observation of the lattice behavior of a single crystal silicon nanobelt during uniaxial tensile testing.An in-situ silicon nanobelt tensile testing device for transmissio...We present an experimental method for in-situ observation of the lattice behavior of a single crystal silicon nanobelt during uniaxial tensile testing.An in-situ silicon nanobelt tensile testing device for transmission electron microscopy is developed.Atomic behavior and lattice parameters of the nanobelt are studied using selected area electron diffraction.A statistical and least square methods are used for reducing the measurement errors of the lattice parameters.The results suggest that the trends of the lattice parameters during the tensile test are in agreement with the increasing tensile stress in the silicon nanobelt.Furthermore,the local strain calculated from lattice parameters and the average strain of the nanobelt are compared.展开更多
Background Adipose-derived stem cells （ADSCs） are capable of differentiating into cardiomyogenic and endothelial cells in vitro. We tested the hypothesis that transplantation of ADSCs into myocardial scar may regene...Background Adipose-derived stem cells （ADSCs） are capable of differentiating into cardiomyogenic and endothelial cells in vitro. We tested the hypothesis that transplantation of ADSCs into myocardial scar may regenerate infracted myocardium and restore cardiac function. Methods ADSCs were isolated from the fatty tissue of New Zealand white rabbits and cultured in Iscove＇s modified dulbecco＇s medium. Three weeks after ligation of left anterior descending coronary artery of rabbits, either a graft of untreated ADSCs （UASCs, n=14）, 5-azacytidine-pretreated ADSCs （AASCs, n=13）, or phosphate buffer saline （n=13） were injected into the infarct region. Transmural scar size, cardiac function, and immunohistochemistry were performed 5 weeks after cell transplantation. Results ADSCs in culture demonstrated a fibroblast-like appearance and expressed CD29, CD44 and CD105. Five weeks after cell transplantation, transmural scar size in AASC-implanted hearts was smaller than that of the other hearts. Many ADSCs were differentiated into cardiomyocytes. The AASCs in the prescar appeared more myotube-like. AASCs in the middle of the scar and UASCs, in contrast, were poorly differentiated. Some ADSCs were differentiated into endothelial cells and participate in vessel-like structures formation. All the ADSC-implanted hearts had a greater capillary density in the infarct region than did the control hearts. Statistical analyses revealed significant improvement in left ventricular ejection fraction, myocardial performance index, end-diastolic pressure, and peak ＋dP/dt, in two groups of ADSC-implanted hearts relative to the control hearts. AASC-implanted hearts had higher peak -dP/dt values than did control, higher ejection fraction and peak ＋dP/dt values than did UASC-implanted hearts. Conclusions ADSCs transplanted into the myocardial scar tissue formed cardiac islands and vessel-like structures, induced angiogenesis and improved cardiac function. 5-Azacytidine pretreatment before implantation is desirable for augmenting myogenesis. Transplantation of 5-azacytidine-treated ADSCs into the myocardial scar was more efficient than that of untreated ADSCs in preservation of cardiac function.展开更多
Background Edge dissections after coronary stent implantation are associated with increased short-term risk of major adverse cardiovascular events. The incidence and outcome of edge dissections after coronary stent im...Background Edge dissections after coronary stent implantation are associated with increased short-term risk of major adverse cardiovascular events. The incidence and outcome of edge dissections after coronary stent implantation were reportedly different using different imaging techniques. We used optical coherence tomography （OCT） to assess the incidence, morphological findings and related factors of edge dissections after drug-eluting stent （DES） implantation. Methods Totally 42 patients with 43 de novo lesions in 43 native arteries undergoing DES implantation with OCT imaging were enrolled in this study. Results Nine edge dissections were detected in 43 arteries after DES implantation. There were four morphological patterns of stent edge dissections indentified in this study： （1） superficial intimal tears （n=3）, （2） subintimal dissections （n=4）, （3） split of media （n=1）, （4） disruption of the fibrotic cap of plaque （n=1）. Stent edge expansion and stent expansion were both higher in the group with dissections than those in the group without dissections （1.682±0.425 vs. 1.229±0.285, P=0.0290; 1.507±0.445 vs. 1.174±0.265, P=0.0072）. Conclusions The incidence of stent edge dissections detected by OCT was 21%. Stent edge dissection is related with stent edge expansion and stent expansion.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB309501,2012CB933301the Key Project of National Natural Science Foundation of China(NSFC)under Grant Nos 60936001,91123037+1 种基金the Youth Project of National Natural Science Foundation of China(NSFC)under Grant No 81201358the Fund for Creative Research of NSFC under Grant No 61021064.
文摘We present an experimental method for in-situ observation of the lattice behavior of a single crystal silicon nanobelt during uniaxial tensile testing.An in-situ silicon nanobelt tensile testing device for transmission electron microscopy is developed.Atomic behavior and lattice parameters of the nanobelt are studied using selected area electron diffraction.A statistical and least square methods are used for reducing the measurement errors of the lattice parameters.The results suggest that the trends of the lattice parameters during the tensile test are in agreement with the increasing tensile stress in the silicon nanobelt.Furthermore,the local strain calculated from lattice parameters and the average strain of the nanobelt are compared.
文摘Background Adipose-derived stem cells （ADSCs） are capable of differentiating into cardiomyogenic and endothelial cells in vitro. We tested the hypothesis that transplantation of ADSCs into myocardial scar may regenerate infracted myocardium and restore cardiac function. Methods ADSCs were isolated from the fatty tissue of New Zealand white rabbits and cultured in Iscove＇s modified dulbecco＇s medium. Three weeks after ligation of left anterior descending coronary artery of rabbits, either a graft of untreated ADSCs （UASCs, n=14）, 5-azacytidine-pretreated ADSCs （AASCs, n=13）, or phosphate buffer saline （n=13） were injected into the infarct region. Transmural scar size, cardiac function, and immunohistochemistry were performed 5 weeks after cell transplantation. Results ADSCs in culture demonstrated a fibroblast-like appearance and expressed CD29, CD44 and CD105. Five weeks after cell transplantation, transmural scar size in AASC-implanted hearts was smaller than that of the other hearts. Many ADSCs were differentiated into cardiomyocytes. The AASCs in the prescar appeared more myotube-like. AASCs in the middle of the scar and UASCs, in contrast, were poorly differentiated. Some ADSCs were differentiated into endothelial cells and participate in vessel-like structures formation. All the ADSC-implanted hearts had a greater capillary density in the infarct region than did the control hearts. Statistical analyses revealed significant improvement in left ventricular ejection fraction, myocardial performance index, end-diastolic pressure, and peak ＋dP/dt, in two groups of ADSC-implanted hearts relative to the control hearts. AASC-implanted hearts had higher peak -dP/dt values than did control, higher ejection fraction and peak ＋dP/dt values than did UASC-implanted hearts. Conclusions ADSCs transplanted into the myocardial scar tissue formed cardiac islands and vessel-like structures, induced angiogenesis and improved cardiac function. 5-Azacytidine pretreatment before implantation is desirable for augmenting myogenesis. Transplantation of 5-azacytidine-treated ADSCs into the myocardial scar was more efficient than that of untreated ADSCs in preservation of cardiac function.
文摘Background Edge dissections after coronary stent implantation are associated with increased short-term risk of major adverse cardiovascular events. The incidence and outcome of edge dissections after coronary stent implantation were reportedly different using different imaging techniques. We used optical coherence tomography （OCT） to assess the incidence, morphological findings and related factors of edge dissections after drug-eluting stent （DES） implantation. Methods Totally 42 patients with 43 de novo lesions in 43 native arteries undergoing DES implantation with OCT imaging were enrolled in this study. Results Nine edge dissections were detected in 43 arteries after DES implantation. There were four morphological patterns of stent edge dissections indentified in this study： （1） superficial intimal tears （n=3）, （2） subintimal dissections （n=4）, （3） split of media （n=1）, （4） disruption of the fibrotic cap of plaque （n=1）. Stent edge expansion and stent expansion were both higher in the group with dissections than those in the group without dissections （1.682±0.425 vs. 1.229±0.285, P=0.0290; 1.507±0.445 vs. 1.174±0.265, P=0.0072）. Conclusions The incidence of stent edge dissections detected by OCT was 21%. Stent edge dissection is related with stent edge expansion and stent expansion.
