血流限制训练的生理机制与应用进展

血流限制训练作为一种安全有效的全新康复手段,可有效提高训练者的身体机能。相较于单纯抗阻训练,血流限制训练具有强度小、效果好和依从性高等优点,适合多数人群使用。血流限制训练的生理机制尚未完全阐明,目前存在四种主流假说,各有特点。本研究对血流限制训练的作用机制与应用进展进行综述,为其推广提供理论和实践依据。

新型化合物N-甲基-N-异丙基硫代辛酰胺从盐酸介质中选择性萃取分离钯

为实现从废汽车尾气净化催化剂的浸出液中高效分离钯,合成一种新化合物N-甲基-N-异丙基硫代辛酰胺(TA-813)。通过FT-IR、1H NMR、ESI-MS和元素分析进行表征,研究TA-813对钯的萃取和反萃行为。通过萃取−反萃循环试验评估TA-813的循环使用性能,并用TA-813从废汽车尾气净化催化剂的模拟浸出液中选择性萃取分离钯。结果表明:TA-813对钯萃取速度快、效率高、选择性好;2个TA-813分子萃取1个Pd;有机相中负载的钯可被中性和酸性硫脲高效反萃;TA-813循环使用性能好,经过8次萃取−反萃循环,钯的萃取率没有降低。在废汽车尾气净化催化剂的模拟浸出液中,Pd的浓度远低于杂质离子La、Ce、Mg和Al等,即便如此,TA-813仍能实现钯的选择性高效分离。

HCV NS5A and NS5B Enhance Expression of Human Ceramide Glucosyltransferase Gene

Host genes involved in lipid metabolism are differentially affected during the early stages of hepatitis C virus （HCV） infection. Here we demonstrate that artificial up-regulation of fatty acid biosynthesis has a positive effect on the replication of the HCV full-length replicon when cells were treated with nystatin. Conversely, the HCV RNA replication was decreased when fatty acid biosynthesis was inhibited with 25-hydroxycholesterol and PDMP（D-threo-l-phenyl-2-decanoylamino-3- morpholino-l-propanol）. In agreement with these results, the expression level of GlcT-l（ceramide glucosyltransferase）, a host glucosyltransferase in the first step of GSL （glycosphingolipid） biosynthesis, was found to be closely associated with the expression and replication of HCV RNA. On the other hand, the viral RNA can also activate GlcT-1 in the early stage of viral RNA transfection in vitro. To identify viral factors that are responsible for GlcT-1 activation, we constructed ten stable Vero cell lines that express individual HCV proteins. Based on the analyses of these cell lines and transient transfection assay of the GlcT-1 promoter regions, we conclude that HCV proteins, especially NS5A and NS5B, have positive effects on the expression of GlcT-1. It is possible that NS5A and NS5B stimulate transcription factor（s） to activate the expression of GlcT-1 by increasing its transcription level

Down-regulation of eIF5A-2 prevents epithelial-mesenchymal transition in non-small-cell lung cancer cells

Background:Epithelial-mesenchymal transition(EMT) is believed to be the critical process in malignant tumor invasion and metastases,and has a great influence on improving the survival rate in non-small-cell lung cancer(NSCLC) patients.Recent studies suggested that eukaryotic initiation factor 5A-2(eIF5A-2) might serve as an adverse prognostic marker of survival.We detected eIF5A-2 in NSCLC A549 cells,and found that the invasive capability correlates with the eIF5A-2 expression.Methods:Transforming growth factor(TGF)-β1 was used to induce EMT in A549 cells.Western blotting,immunofluorescence,wound healing assay,and transwell-matrigel invasion chambers were used to identify phenotype changes.Western blotting was also used to observe changes of the expression of eIF5A-2.We down-regulated the eIF5A-2 expression using an eIF5A-2 siRNA and identified the phenotype changes by western blotting and immunofluorescence.We tested the change of migration and invasion capabilities of A549 cells by the wound healing assay and transwell-matrigel invasion chambers.Results:After stimulating with TGF-β1,almost all A549 cells changed to the mesenchymal phenotype and acquired more migration and invasion capabilities.These cells also had higher eIF5A-2 protein expression.Down-regulation of eIF5A-2 expression with eIF5A-2 siRNA transfection could change the cells from mesenchymal to epithelial phenotype and decrease tumor cell migration and invasive capabilities significantly.Conclusions:The expression of eIF5A-2 was up-regulated following EMT phenotype changes in A549 cells,which correlated with enhanced tumor invasion and metastatic capabilities.Furthermore,in the A549 cell line,the process of EMT phenotype change could be reversed by eIF5A-2 siRNA,with a consequent weakening of both invasive and metastatic capabilities.

Effects of pulse magneto-oscillation on GCr15 bearing steel continuous casting billet

Pulse magneto-oscillation(PMO)added during solidification could affect the solidification structure and macrosegregation.A modified thermal simulation equipment was applied to prepare GCr15 bearing steel continuous casting billets with different PMO peak currents.Then,metallographic analysis,component analysis and numerical simulation were adopted to study the influence of PMO peak current and its mechanism.The sample with 150 K_(I)A PMO peak current treatment has little difference with the samples without PMO treatment on solidification structure and macrosegregation.As the peak currents are 250 and 350 K_(I)A,the columnar zone increases and macrosegregation aggravated.When 450 K_(I)A peak current is selected,the equiaxed grain ratio is enlarged,and the dendritic grains are refined,and the macrosegregation of C,Cr,Si and Mn is decreased significantly.By analyzing,different convections induced by PMO with various peak currents are the key factor to change the solidification structure and macrosegregation.