To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial co...To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints.展开更多
Objective To introduce a novel Cobb protractor and assess its reliability and rapidity for measuring Cobb angle in scoliosis patients. Methods The novel Cobb protractor had two endplate markers. A measurement was perf...Objective To introduce a novel Cobb protractor and assess its reliability and rapidity for measuring Cobb angle in scoliosis patients. Methods The novel Cobb protractor had two endplate markers. A measurement was performed just to align the two markers to each endplate of the curve. The Cobb angle on the posteroanterior radiographs of 24 patients clinically diagnosed with adolescent idiopathic scoliosis was measured by three orthopedic surgeons with both standard Cobb method and the new technique, and the time of measurement was recorded. Intraclass correlation coefficients(ICCs) were calculated to assess the reliability of the new method. Results The time for a measurement with the new tool was approximately 10 seconds less than the time that used to finish a measurement with the standard method(P<0.05). The overall mean Cobb angle for the major curve of the 24 patients was 47.8°. The mean overall intraobserver and interobserver ICC was 0.971 and 0.971 for the Cobb method group, while the overall intraobserver ICC and the interobserver was 0.985 and 0.979 for the new tool group. Conclusions The novel Cobb protractor could perform quick measurement and measure almost all forms of radiographs. The Cobb protractor might be an ideal instrument to measure the Cobb angle.展开更多
Objective： To identify radiographic predictors of residual low back pain （LBP） after laminectomy for lumbar canal stenosis Methods： （LCS） Clinical results and radiographic findings in 69 patients who underwent ...Objective： To identify radiographic predictors of residual low back pain （LBP） after laminectomy for lumbar canal stenosis Methods： （LCS） Clinical results and radiographic findings in 69 patients who underwent single level laminectomy for LCS were retrospectively reviewed. Patients who had an improvement in LBP scores evaluated by Japanese Orthopaedic Association （JOA） scoring system during the fol- low-up periods were classified as the recovery group, and others were classified as the non-recovery group. Patients＇ clinical data and radiographic parameters like lordosis angle, range of motion and intervertebral rotational angle were analyzed using binary logistic regression analysis to detect factors significantly related with the occurrence of residual LBP. Results： The average preoperative JOA score of 14.8± 5.05 improved to 21.59±5.51 at the final follow-up. Binary logistic regression analysis revealed that significant predictors of residual LBP were preoperative lumbar lordosis angle and range of motion. Conclusions： Our results suggest that patients with flat back and limited lumbar mobility before surgery tend to have poor results in terms of LBP. Therefore, these sagittal radiographic parameters should be taken into account when choosing laminectomy as the surgical option for LCS.展开更多
Solvothermal reaction of Zn（NO3）2, 4-（1H-pyrazol-4-yl）pyridine （Hpypz） and 1,3,5-benzenetricarboxylic acid （H3btc） in N,N-dimethylacetamide （DMA） produced a new porous coordination polymer [Zns（pypz）4（btc...Solvothermal reaction of Zn（NO3）2, 4-（1H-pyrazol-4-yl）pyridine （Hpypz） and 1,3,5-benzenetricarboxylic acid （H3btc） in N,N-dimethylacetamide （DMA） produced a new porous coordination polymer [Zns（pypz）4（btc）2] （1）. Single-crystal X-ray diffraction study of 1 showed that deprotonated pypz^- ligands served as 1,2,4-triazolate-like ligands, linking Zn（II） ^＋ ions to form porous two-dimensional （2-D） sql-a layers {Zn（pypz）} , which were further connected by eight-legged pillars {Zn2（btc）4（H2O）2}8- based on the typical paddlewheel dinuclear Zn2（RCOO）4（H20）2 cluster to form a novel type of non-interpenetrated pillared-layer framework with 3-D intersecting pore system and large pore volume. Gas sorption measurements revealed that 1 possesses large BET surface area of 2061 m^2g^-1 and very high methane total uptake of 245 cm^3（STP） cm^-3 at 298 K and 65 bar.展开更多
基金Supported by National Natural Science Foundation of China (No. 50878141)Hebei Natural Science Foundation,China (No. E2011202013)High School of Hebei Science and Technology Research Youth Foundation,China(No. Q2012083)
文摘To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints.
文摘Objective To introduce a novel Cobb protractor and assess its reliability and rapidity for measuring Cobb angle in scoliosis patients. Methods The novel Cobb protractor had two endplate markers. A measurement was performed just to align the two markers to each endplate of the curve. The Cobb angle on the posteroanterior radiographs of 24 patients clinically diagnosed with adolescent idiopathic scoliosis was measured by three orthopedic surgeons with both standard Cobb method and the new technique, and the time of measurement was recorded. Intraclass correlation coefficients(ICCs) were calculated to assess the reliability of the new method. Results The time for a measurement with the new tool was approximately 10 seconds less than the time that used to finish a measurement with the standard method(P<0.05). The overall mean Cobb angle for the major curve of the 24 patients was 47.8°. The mean overall intraobserver and interobserver ICC was 0.971 and 0.971 for the Cobb method group, while the overall intraobserver ICC and the interobserver was 0.985 and 0.979 for the new tool group. Conclusions The novel Cobb protractor could perform quick measurement and measure almost all forms of radiographs. The Cobb protractor might be an ideal instrument to measure the Cobb angle.
文摘Objective： To identify radiographic predictors of residual low back pain （LBP） after laminectomy for lumbar canal stenosis Methods： （LCS） Clinical results and radiographic findings in 69 patients who underwent single level laminectomy for LCS were retrospectively reviewed. Patients who had an improvement in LBP scores evaluated by Japanese Orthopaedic Association （JOA） scoring system during the fol- low-up periods were classified as the recovery group, and others were classified as the non-recovery group. Patients＇ clinical data and radiographic parameters like lordosis angle, range of motion and intervertebral rotational angle were analyzed using binary logistic regression analysis to detect factors significantly related with the occurrence of residual LBP. Results： The average preoperative JOA score of 14.8± 5.05 improved to 21.59±5.51 at the final follow-up. Binary logistic regression analysis revealed that significant predictors of residual LBP were preoperative lumbar lordosis angle and range of motion. Conclusions： Our results suggest that patients with flat back and limited lumbar mobility before surgery tend to have poor results in terms of LBP. Therefore, these sagittal radiographic parameters should be taken into account when choosing laminectomy as the surgical option for LCS.
基金supported by the National Basic Research Program of China (2014CB845602)the National Natural Science Foundation of China (21225105, 21473260)the Natural Science Foundation of Guangdong (S2012030006240)
文摘Solvothermal reaction of Zn（NO3）2, 4-（1H-pyrazol-4-yl）pyridine （Hpypz） and 1,3,5-benzenetricarboxylic acid （H3btc） in N,N-dimethylacetamide （DMA） produced a new porous coordination polymer [Zns（pypz）4（btc）2] （1）. Single-crystal X-ray diffraction study of 1 showed that deprotonated pypz^- ligands served as 1,2,4-triazolate-like ligands, linking Zn（II） ^＋ ions to form porous two-dimensional （2-D） sql-a layers {Zn（pypz）} , which were further connected by eight-legged pillars {Zn2（btc）4（H2O）2}8- based on the typical paddlewheel dinuclear Zn2（RCOO）4（H20）2 cluster to form a novel type of non-interpenetrated pillared-layer framework with 3-D intersecting pore system and large pore volume. Gas sorption measurements revealed that 1 possesses large BET surface area of 2061 m^2g^-1 and very high methane total uptake of 245 cm^3（STP） cm^-3 at 298 K and 65 bar.
