目的测量不同骨密度(bone mineral density,BMD)条件下椎体松质骨显微结构参数,并与椎弓根螺钉拔出力作相关性分析,以了解与螺钉稳定性相关的骨显微结构参数,进一步明确螺钉松动的原因。方法采用新鲜尸体脊柱标本,根据BMD检测结果,按临...目的测量不同骨密度(bone mineral density,BMD)条件下椎体松质骨显微结构参数,并与椎弓根螺钉拔出力作相关性分析,以了解与螺钉稳定性相关的骨显微结构参数,进一步明确螺钉松动的原因。方法采用新鲜尸体脊柱标本,根据BMD检测结果,按临床诊断标准分为骨质正常、骨量减少、骨质疏松和重度骨质疏松4个水平。然后植入椎弓根螺钉,进行螺钉轴向拔出实验,测定最大拔出力(maximum pullout strength,MPS)。收集螺钉拔出实验后椎体标本,在椎体中央部钻取松质骨柱状样本,对样本进行显微CT扫描,获取椎体松质骨显微结构参数,并进行各项指标的不同BMD水平间的比较分析,在了解这些指标随骨质疏松程度加重的变化规律的基础上,再对骨显微结构参数与所对应的螺钉MPS开展相关性分析。结果 BMD水平从正常下降到重度疏松程度,MPS随之显著性下降。随BMD水平的依梯次下降,即骨质疏松程度进行性加重,椎体松质骨显微结构参数发生相应明显变化,存在BMD水平间的显著性差异。广泛的相关性存在于BMD、显微CT参数和螺钉MPS指标之间。其中,螺钉MPS与显微CT扫描所得的骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)和小梁间隙(Tb.Sp)呈高度相关性。结论随BMD下降,骨组织会同时发生质的退变;螺钉MPS与部分骨显微结构参数高度相关。展开更多
Electrochemical hydrogenation of anthracene was carr ie d out in a divided three-electrode cell with spumous Pb as cathode, Pt as anode and saturated calomel electrode as reference electrode in CH 3CN-EtOH-H 2O -Bu 4N...Electrochemical hydrogenation of anthracene was carr ie d out in a divided three-electrode cell with spumous Pb as cathode, Pt as anode and saturated calomel electrode as reference electrode in CH 3CN-EtOH-H 2O -Bu 4NBr electrolytic system.The curve of current-potential was determined an d the effects of solvents, water content, supporting electrolyte, anthracene con tent and temperature were investigated.The optimum conditions were found as pote ntial=-1900 mV, [CH 3CN]/[EtOH]=2/1(vol),[H 2O]=5.5 mol·L -1, [Bu 4NBr]=0.50 mol·L -1 and T=35 ℃.The yield of dihydroanthracen e was 91.37% for 6 h electrolysis under these conditions.Based on the result of electrochemical hydrogenation of anthracene,electrochemical hydrogenation of Da qing FCC diesel fuel was studied with spumous Pb as cathode in CH 3CN-EtOH-H 2O-Bu 4NBr system for 5 h electrolysis.Hydrogen content of diesel fuel incre ased by 1.1%,alkenes were saturated and polycyclic aromatics decreased apparent ly.展开更多
文摘Electrochemical hydrogenation of anthracene was carr ie d out in a divided three-electrode cell with spumous Pb as cathode, Pt as anode and saturated calomel electrode as reference electrode in CH 3CN-EtOH-H 2O -Bu 4NBr electrolytic system.The curve of current-potential was determined an d the effects of solvents, water content, supporting electrolyte, anthracene con tent and temperature were investigated.The optimum conditions were found as pote ntial=-1900 mV, [CH 3CN]/[EtOH]=2/1(vol),[H 2O]=5.5 mol·L -1, [Bu 4NBr]=0.50 mol·L -1 and T=35 ℃.The yield of dihydroanthracen e was 91.37% for 6 h electrolysis under these conditions.Based on the result of electrochemical hydrogenation of anthracene,electrochemical hydrogenation of Da qing FCC diesel fuel was studied with spumous Pb as cathode in CH 3CN-EtOH-H 2O-Bu 4NBr system for 5 h electrolysis.Hydrogen content of diesel fuel incre ased by 1.1%,alkenes were saturated and polycyclic aromatics decreased apparent ly.
