The impact of carbon emission and other pollution generated by the construction industry on the natural environment and ecosystems is immeasurable.Wood,as a renewable building material with excellent performance,is a ...The impact of carbon emission and other pollution generated by the construction industry on the natural environment and ecosystems is immeasurable.Wood,as a renewable building material with excellent performance,is a practical solution for future low-carbon buildings.Current screwed wood connections have good ductility,but the initial stiffness is relatively low.In this paper,composite wood connections with screw and adhesive were proposed and investigated.Static loading tests were conducted to screwed connections and composite connection specimens.The failure modes of different connection types,as well as the effects of adhesive type and adhesive connection area on the joint bearing capacity are discussed.The results show that the yield load and ultimate load of the composite joint made with the existing adhesive increased by up to 169%and 222%,respectively,compared with the screw connection.At the same time,the influence of curing time and bonding should also be taken into consideration.This study provides a foundation for wood joint design and promotes the sustainable development of the building industry.展开更多
Objective： To explore the advantages and indications of the paraspinal approach by anatomical study and clinical application.Methods： The anatomical data and clinical practice of 27 cases were analyzed to explore th...Objective： To explore the advantages and indications of the paraspinal approach by anatomical study and clinical application.Methods： The anatomical data and clinical practice of 27 cases were analyzed to explore the accurate approach between the paraspinal muscles and the structure of ambient tissues, as well as the results of clinical application of paraspinal approach. The operation time, blood loss, incision length, radiographic result （Cobb angle, height of anterior edge of the vertebrae） were compared with those in 24cases treated by traditional approach.Results： Complete exposure of the facets could be easily performed by identifying natural cleavage plane between the multifidus and Iongissimus muscles. The natural muscular cleavage was （1.47±0.23） cm lateral to the midline for females, and （1.64±0.35） cm for males at T12 level. The distance was （3.3±0.6） cm lateral to the midline for females,and （3.7±1.0） cm for males at L4 level. In paraspinal approach group, the operation time was （76.2±15.7） min, blood loss was （91.6±16.9） ml and incision length was （7.6±0.8） cm. In traditional approach group, the operation time was （121.4±19.6） min, blood loss was （218.7±32.3 ） ml and incision length was （17.4±2.1） cm. To compare paraspinal approach with traditional approach, the operation time, blood loss and incision length had statistical difference （P〈0.05） and the radiographic result （Cobb angle, height of anterior edge of the vertebrae） had no statistical difference （P〉0.05）.Conclusions： When the paraspinal approach is performed through natural cleavage plane between the multifidus and longissimus muscles, there are no wide muscular disinsertions, leaving the supraspinous and interspinous ligaments intact. The distance of natural cleavage to the midline is different at T12 and L4 planes. By this approach,the facet joints can be explored easily and completely, and a clear surgical field will be available for the placement of pedicle screws. As a minimally invasive approach, it can be widely used in thoracolumbar spine surgery.展开更多
基金the National Natural Science Foundation of China(Grant No.52208270)for supporting this research.
文摘The impact of carbon emission and other pollution generated by the construction industry on the natural environment and ecosystems is immeasurable.Wood,as a renewable building material with excellent performance,is a practical solution for future low-carbon buildings.Current screwed wood connections have good ductility,but the initial stiffness is relatively low.In this paper,composite wood connections with screw and adhesive were proposed and investigated.Static loading tests were conducted to screwed connections and composite connection specimens.The failure modes of different connection types,as well as the effects of adhesive type and adhesive connection area on the joint bearing capacity are discussed.The results show that the yield load and ultimate load of the composite joint made with the existing adhesive increased by up to 169%and 222%,respectively,compared with the screw connection.At the same time,the influence of curing time and bonding should also be taken into consideration.This study provides a foundation for wood joint design and promotes the sustainable development of the building industry.
基金This study was supported by National Natural Science Foundation of China （No.30772209）.
文摘Objective： To explore the advantages and indications of the paraspinal approach by anatomical study and clinical application.Methods： The anatomical data and clinical practice of 27 cases were analyzed to explore the accurate approach between the paraspinal muscles and the structure of ambient tissues, as well as the results of clinical application of paraspinal approach. The operation time, blood loss, incision length, radiographic result （Cobb angle, height of anterior edge of the vertebrae） were compared with those in 24cases treated by traditional approach.Results： Complete exposure of the facets could be easily performed by identifying natural cleavage plane between the multifidus and Iongissimus muscles. The natural muscular cleavage was （1.47±0.23） cm lateral to the midline for females, and （1.64±0.35） cm for males at T12 level. The distance was （3.3±0.6） cm lateral to the midline for females,and （3.7±1.0） cm for males at L4 level. In paraspinal approach group, the operation time was （76.2±15.7） min, blood loss was （91.6±16.9） ml and incision length was （7.6±0.8） cm. In traditional approach group, the operation time was （121.4±19.6） min, blood loss was （218.7±32.3 ） ml and incision length was （17.4±2.1） cm. To compare paraspinal approach with traditional approach, the operation time, blood loss and incision length had statistical difference （P〈0.05） and the radiographic result （Cobb angle, height of anterior edge of the vertebrae） had no statistical difference （P〉0.05）.Conclusions： When the paraspinal approach is performed through natural cleavage plane between the multifidus and longissimus muscles, there are no wide muscular disinsertions, leaving the supraspinous and interspinous ligaments intact. The distance of natural cleavage to the midline is different at T12 and L4 planes. By this approach,the facet joints can be explored easily and completely, and a clear surgical field will be available for the placement of pedicle screws. As a minimally invasive approach, it can be widely used in thoracolumbar spine surgery.
