Background Accurate knowledge of the spinal structural functions is critical to understand the biomechanical factors that affect spinal pathology. Many studies have investigated the human vertebral motion both in vitr...Background Accurate knowledge of the spinal structural functions is critical to understand the biomechanical factors that affect spinal pathology. Many studies have investigated the human vertebral motion both in vitro and in vivo. However, determination of in vivo motion of the vertebrae under physiologic loading conditions remains a challenge in biomedical engineering because of the limitations of current technology and the complicated anatomy of the spine. Methods For in vitro validation, a human lumbar specimen was imbedded with steel beads and moved to a known distance by an universal testing machine （UTM）.展开更多
目的探讨不同术式治疗颈椎后纵韧带骨化症(ossification of posterior longitudinal ligament,OPLL)的疗效和MRI T2脊髓高信号(increased signal intensity,ISI)对预后的影响。方法分析132例因OPLL行手术治疗的病例,其中前路手术46例,...目的探讨不同术式治疗颈椎后纵韧带骨化症(ossification of posterior longitudinal ligament,OPLL)的疗效和MRI T2脊髓高信号(increased signal intensity,ISI)对预后的影响。方法分析132例因OPLL行手术治疗的病例,其中前路手术46例,后路手术59例,前后路联合手术27例。统计手术前后JOA评分及术后改善率,分析不同术式的疗效及MRI T2脊髓高信号对预后的影响。结果三组病例JOA评分均较术前明显提高,差异有统计学意义;前路组改善率为(74.95±9.83)%,后路组改善率为(69.90±9.56)%,前后路联合组改善率为(76.61±10.19)%,前路组和前后路联合组的改善率均优于后路组,差异有统计学意义;术前有ISI组改善率为(67.04±7.91)%,无ISI组改善率为(77.88±9.11)%,差异有统计学意义。结论a)三种术式均可获得较好的疗效,但前路手术和前后路联合手术的改善率优于后路手术;b)术前无MRI T2脊髓高信号者的预后相对较好。展开更多
Human motion induced vibration has very low frequency,ranging from 2 Hz to 5 Hz.Traditional vibration isolators are not effective in low-frequency regions due to the trade-off between the low natural frequency and the...Human motion induced vibration has very low frequency,ranging from 2 Hz to 5 Hz.Traditional vibration isolators are not effective in low-frequency regions due to the trade-off between the low natural frequency and the high load capacity.In this paper,inspired by the human spine,we propose a novel bionic human spine inspired quasi-zero stiffness(QZS)vibration isolator which consists of a cascaded multi-stage negative stiffness structure.The force and stiffness characteristics are investigated first,the dynamic model is established by Newton’s second law,and the isolation performance is analyzed by the harmonic balance method(HBM).Numerical results show that the bionic isolator can obtain better low-frequency isolation performance by increasing the number of negative structure stages,and reducing the damping values and external force values can obtain better low-frequency isolation performance.In comparison with the linear structure and existing traditional QZS isolator,the bionic spine isolator has better vibration isolation performance in low-frequency regions.It paves the way for the design of bionic ultra-low-frequency isolators and shows potential in many engineering applications.展开更多
目的:探讨简易"针内针"水平法行蛛网膜下腔阻滞(腰麻)的可行性与效果。方法:择期行下肢及会阴手术患者40例,随机分为腰硬联合穿刺组(对照组)和9号皮针导引针内针腰麻穿刺组(观察组),各20例。2组均在L3与L4间隙行蛛网膜下腔穿...目的:探讨简易"针内针"水平法行蛛网膜下腔阻滞(腰麻)的可行性与效果。方法:择期行下肢及会阴手术患者40例,随机分为腰硬联合穿刺组(对照组)和9号皮针导引针内针腰麻穿刺组(观察组),各20例。2组均在L3与L4间隙行蛛网膜下腔穿刺,成功后注入0.75%布比卡因2 m L。对照组用16号硬膜外针先行硬膜外穿刺,后用5号腰硬联合针行蛛网膜下腔穿刺;观察组用9号皮针引导,直接用5号腰硬联合针行蛛网膜下腔穿刺。所有引导针的针尖斜面均与脊柱轴线平行,观察2组腰麻穿刺成功率、黄韧带和硬脊膜突破感知率、神经阻滞效果及术后头痛、腰痛、穿刺点痛发生情况。结果:观察组穿刺时间与对照组的差异无统计学意义(P>0.05);2组细腰针突破硬脊膜时均有确切的纸质破裂感或阻力落空感差异无统计学意义(P>0.05);2组穿刺成功率均为95%;2组感觉阻滞平面、感觉阻滞起效时间和运动神经阻滞起效时间差异均无统计学意义(P>0.05)。术后随访:2组皆无体位性头痛发生,但观察组术后第5天和第7天穿刺点痛和腰痛发生率均低于对照组(P<0.01)。结论:9号皮针引导"针内针"水平法腰穿可以确切感知突破硬脊膜,脑脊液流出通畅,腰麻麻醉效果确切,术后穿刺点疼痛及腰痛发生率低。展开更多
The aim of this paper is to develop computational models for the ultimate compressive strength analysis of stiffened plate panels with nonuniform thickness.Modeling welding-induced initial deformations and residual st...The aim of this paper is to develop computational models for the ultimate compressive strength analysis of stiffened plate panels with nonuniform thickness.Modeling welding-induced initial deformations and residual stresses was presented with the measured data.Three methods,i.e.,ANSYS finite element method,ALPS/SPINE incremental Galerkin method,and ALPS/ULSAP analytical method,were employed together with existing test database obtained from a full-scale collapse testing of steel-stiffened plate structures.Sensitivity study was conducted with varying the difference in plate thickness to define a representative(equivalent)thickness for plate panels with nonuniform thickness.Guidelines are provided for structural modeling to compute the ultimate compressive strength of plate panels with variable thickness.展开更多
文摘Background Accurate knowledge of the spinal structural functions is critical to understand the biomechanical factors that affect spinal pathology. Many studies have investigated the human vertebral motion both in vitro and in vivo. However, determination of in vivo motion of the vertebrae under physiologic loading conditions remains a challenge in biomedical engineering because of the limitations of current technology and the complicated anatomy of the spine. Methods For in vitro validation, a human lumbar specimen was imbedded with steel beads and moved to a known distance by an universal testing machine （UTM）.
文摘目的探讨不同术式治疗颈椎后纵韧带骨化症(ossification of posterior longitudinal ligament,OPLL)的疗效和MRI T2脊髓高信号(increased signal intensity,ISI)对预后的影响。方法分析132例因OPLL行手术治疗的病例,其中前路手术46例,后路手术59例,前后路联合手术27例。统计手术前后JOA评分及术后改善率,分析不同术式的疗效及MRI T2脊髓高信号对预后的影响。结果三组病例JOA评分均较术前明显提高,差异有统计学意义;前路组改善率为(74.95±9.83)%,后路组改善率为(69.90±9.56)%,前后路联合组改善率为(76.61±10.19)%,前路组和前后路联合组的改善率均优于后路组,差异有统计学意义;术前有ISI组改善率为(67.04±7.91)%,无ISI组改善率为(77.88±9.11)%,差异有统计学意义。结论a)三种术式均可获得较好的疗效,但前路手术和前后路联合手术的改善率优于后路手术;b)术前无MRI T2脊髓高信号者的预后相对较好。
基金supported by the National Natural Science Foundation of China(No.12072221)the Natural Science Foundation of Liaoning Province of China(No.2019-KF-01-09)。
文摘Human motion induced vibration has very low frequency,ranging from 2 Hz to 5 Hz.Traditional vibration isolators are not effective in low-frequency regions due to the trade-off between the low natural frequency and the high load capacity.In this paper,inspired by the human spine,we propose a novel bionic human spine inspired quasi-zero stiffness(QZS)vibration isolator which consists of a cascaded multi-stage negative stiffness structure.The force and stiffness characteristics are investigated first,the dynamic model is established by Newton’s second law,and the isolation performance is analyzed by the harmonic balance method(HBM).Numerical results show that the bionic isolator can obtain better low-frequency isolation performance by increasing the number of negative structure stages,and reducing the damping values and external force values can obtain better low-frequency isolation performance.In comparison with the linear structure and existing traditional QZS isolator,the bionic spine isolator has better vibration isolation performance in low-frequency regions.It paves the way for the design of bionic ultra-low-frequency isolators and shows potential in many engineering applications.
文摘目的:探讨简易"针内针"水平法行蛛网膜下腔阻滞(腰麻)的可行性与效果。方法:择期行下肢及会阴手术患者40例,随机分为腰硬联合穿刺组(对照组)和9号皮针导引针内针腰麻穿刺组(观察组),各20例。2组均在L3与L4间隙行蛛网膜下腔穿刺,成功后注入0.75%布比卡因2 m L。对照组用16号硬膜外针先行硬膜外穿刺,后用5号腰硬联合针行蛛网膜下腔穿刺;观察组用9号皮针引导,直接用5号腰硬联合针行蛛网膜下腔穿刺。所有引导针的针尖斜面均与脊柱轴线平行,观察2组腰麻穿刺成功率、黄韧带和硬脊膜突破感知率、神经阻滞效果及术后头痛、腰痛、穿刺点痛发生情况。结果:观察组穿刺时间与对照组的差异无统计学意义(P>0.05);2组细腰针突破硬脊膜时均有确切的纸质破裂感或阻力落空感差异无统计学意义(P>0.05);2组穿刺成功率均为95%;2组感觉阻滞平面、感觉阻滞起效时间和运动神经阻滞起效时间差异均无统计学意义(P>0.05)。术后随访:2组皆无体位性头痛发生,但观察组术后第5天和第7天穿刺点痛和腰痛发生率均低于对照组(P<0.01)。结论:9号皮针引导"针内针"水平法腰穿可以确切感知突破硬脊膜,脑脊液流出通畅,腰麻麻醉效果确切,术后穿刺点疼痛及腰痛发生率低。
文摘The aim of this paper is to develop computational models for the ultimate compressive strength analysis of stiffened plate panels with nonuniform thickness.Modeling welding-induced initial deformations and residual stresses was presented with the measured data.Three methods,i.e.,ANSYS finite element method,ALPS/SPINE incremental Galerkin method,and ALPS/ULSAP analytical method,were employed together with existing test database obtained from a full-scale collapse testing of steel-stiffened plate structures.Sensitivity study was conducted with varying the difference in plate thickness to define a representative(equivalent)thickness for plate panels with nonuniform thickness.Guidelines are provided for structural modeling to compute the ultimate compressive strength of plate panels with variable thickness.
