骨盆内入路治疗髋臼后柱骨折的研究进展

髋臼后柱的手术入路,一直是创伤骨科研究热点之一。目前常规使用的“后侧入路”和“前后联合入路”,各有优势,又均存在许多不足。随着临床与基础研究的不断深入,越来越多的术者选择骨盆内入路,取得了良好的效果。按照Letournel-Judet分型系统,髋臼骨折分为前柱骨折、后柱骨折、后壁骨折、前壁骨折、横行骨折、前柱加后半横行骨折、横行加后壁骨折、后柱加后壁骨折、T形骨折、双柱骨折。     

Development of local connections in ferret somatosensory cortex

Ferrets have become recognized as a useful and interesting model for study of neocortical development. Because of their immaturity at birth, it is possible to study very early events in the ontogeny of the brain. We used living slices of ferret somatosensory cortex to study the formation and development of intrinsic elements within the neocortex. A small number of fixed, hemisected brains injected with 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) were also used. The slices were obtained from ferret kits aged postnatal day (P)1 to P62 and maintained in a chamber; each slice received injections of fluorescent-labeled dextrans. The injections were made at different ages in several distinct sites, which included the proliferative ventricular zone, the intervening white matter (or intermediate zone), and different sites of developing cortex, including the deeper cortical plate, which incorporated the subplate in young animals, and more superficial cortical sites, depending on the age of the animal. Several animals also received injections into the ventrobasal thalamus. Injections into young animals (P1–7) produced a dominant radial pattern that extended from the ventricular zone into the cortex. Injections into the ventricular zone labeled many cells that appeared morphologically like radial glia as well as presumptive neurons. Although the predominant pattern was radial, injections in the ventricular zone often produced tangentially oriented cells and horizontally arranged fibers at the outer edge of the proliferative zone. These cells and fibers may provide a substrate for tangential dispersion of neurons within the neocortex. More superficial injections within the slice labeled lines of cells that appeared to be stacked upon one another in a radial pile in the cortex; the cortical plate received very few lateral projections. Data obtained from more mature slices indicated that, although the overall pattern of staining remained radial, the precise character of the pattern changed to include more lateral spread into surrounding cortex, which eventually refined and developed into distinct patches by P28, when the overall cortical architecture appeared adult like. The data involving thalamocortical connections were more limited, but they indicated that the thalamus projects precisely to the somatosensory cortex in a point-to-point fashion from the earliest date studied (P0) and that the ventrobasal nucleus terminates upon the somatosensory cortex in a patchy manner during the early postnatal days of development. This study of the development of the somatosensory cortex confirms the ubiquitous nature of column-like connections throughout the neocortex and provides a novel view of the radial nature of early neocortical maturation. © Wiley-Liss, Inc.     

The vertebral column—A phylogenetic failure? A theory explaining the function and vulnerability of the human spine

The increase in degenerative diseases of the vertebral column is often attributed to an inadequate adaptation to the upright posture in the human. On the basis of a precise analysis of the motion segments, an attempt has here been made to demonstrate that the design of the vertebrae in both the larger mammals and in humans has resulted in no qualitative differences between the stresses to which either is subjected. In the course of evolution there has certainly been an obvious conflict in aims between the need for essential stability and the desired or necessary mobility. These mutually self-limiting mechanisms are reflected in the highly specialized architecture of the ligamentous apparatus and vertebral joints. We conclude that the human vertebral column seems to be an optimized compromise of evolution. © 1996 Wiley-Liss, Inc.     

Changes in dynamin and actin mRNA expression in the dorsal column-medial lemniscal system following dorsal column lesion

Transection of the third cervical hindlimb dorsal column nerve fibers in the spinal cord leads to a partial deafferentation atrophy of the neurons of the ascending dorsal column-medial lemniscal neural network (DC-ML) up to the cortex. We now examine the alteration of the steady-state level mRNA coding for the synaptic vesicle protein, dynamin I, and the cytoskeletal protein β-actin as early indicators of direct and trans-synaptic changes in the relay nuclei of the DC-ML. Rats were sacrificed at 6, 24, 72, and 240 hr after C3 hindlimb dorsal column or sham lesion. By 24 hr, there are changes in the steady-state levels of mRNA coding for both dynamin I and β-actin in regions of the brain containing the first (nucleus gracilis of medulla) and third synaptic relays (cortex). β-actin mRNA is increased at both 6 and 24 hr in the nucleus gracilis. The changes in dynamin I mRNA in the nucleus gracilis are early and biphasic, elevated at 6 hr but decreased compared to sham by 24 hr. In both regions, the initial fluctuations of dynamin I and β-actin mRNA levels are transient. By 72 hr, the levels are no different from those of sham-lesioned animals. In the somatomotor cortex, there is an additional increase in β-actin mRNA levels at 240 hr. The increased steady-state levels of dynamin and actin mRNA following a hindlimb dorsal column lesion suggest that increased synaptic vesicle recycling and actin cytoskeleton rearrangement are some of the early responses to deafferentation made by the neurons of the DC-ML synaptic relays. © 1996 Wiley-Liss, Inc.     

海桐花蕾挥发油的GC-MS分析

目的:提取海桐花蕾中的挥发性成分。方法:采用固相微萃取法和水蒸气蒸馏法,并用GC-MS测定其化学成分,分别鉴定了67种和41种成分,并用归一化法测定其相对百分含量。结果:与水蒸气蒸馏法相比,固相微萃取法得到的十一烷、壬烷、α-荜澄茄油烯等的含量增加;同时提取出了水蒸气蒸馏法不能蒸馏出来的一些成分,如:α-胡椒烯、α-金合欢烯、β-月桂烯、马鞭草烯等。结论:采用固相微萃取法和水蒸汽蒸馏法,提取挥发油的时间明显缩短     

Influence of the Shear Cap Size and Stiffness on the Distribution of Shear Forces in Flat Slabs

The scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connections-reinforced concrete structure. The effect of support (shear cap) stiffness on the calculation of the length of the shear control perimeter according to the available methods is presented. Based on the analysis, the authors indicate in what range of support stiffness the corner concentrations become important in the calculation of the punching resistance. For shear caps with high flexibility (α1 ≤ 0.5), the concentration of internal forces in the corners does not occur. The authors compare the numerical results obtained from the calculation methods and indicate the correlations, which can be useful guidance for structural designers. In the case of large shear caps, the simplified MC2010 method gives a significantly lower value of the effective control perimeter length compared to more accurate methods. This paper is intended to provide scientists, civil engineers, and designers with guidelines on which factors influence punching shear load capacity of the slab–column connections with shear caps.     

The Investigation on Mechanical Performances of High-Strength Steel Reinforced Concrete Composite Short Columns under Axial Load

At present, the existing standards (AISC360-16, EN1994-1-1:2004, and JGJ138-2016) lack relevant provisions for steel-reinforced concrete (SRC) composite columns with high-strength steel. To investigate the axial compressive mechanical performance of short high-strength steel-reinforced concrete (HSSRC) columns, the axial load test was conducted on 12 short composite columns with high-strength steel and ordinary steel. The influences of steel strength, steel ratio, and the section form of steel on the failure modes, bearing capacity, and ductility of the specimens were studied. Afterward, the experimental data were compared with the existing calculation results. The results show: compared with the specimens with Q235 steel, the bearing capacity of the specimens with Q460 steel increases by 7.8–15.3%, the bearing capacity of the specimens with Q690 steel increases by 13.2–24.1%, but the ductility coefficient increases by 15.2–202.4%; with the increase of steel ratio, the bearing capacity and ductility of specimens are significantly improved. A change of the steel cross-section could influence the ductility of SRC columns more than their bearing capacity. Moreover, the calculation results show that present standards could not predict the bearing capacity of HSSRC columns. Therefore, a modified method for determining the effective strength of steel equipped in HSSRC columns was proposed. The results of the ABAQUS simulation also showed that the addition of steel fibers could significantly improve the bearing capacity of Q690 HSSRC columns. The research results provide a reference for engineering practices.     

矿化垃圾的重金属淋溶试验研究

通过土柱实验模拟矿化垃圾以及矿化垃圾与污泥混合物在淋溶条件下重金属的淋失情况,并利用污染综合指数法分析矿化垃圾中重金属迁移对地下水的影响.结果表明淋溶的不同阶段对地下水易造成污染的金属元素有所不同,需要分阶段进行监控.淋溶初期需监测[As]、[Cr]、[Co]、[Cu]和[Mn];淋溶中期需监测[Ni]和[Pb];淋溶末期需对[Fe]进行监测.综合污染指数评价表明矿化垃圾以及矿化垃圾与污泥混合土壤的淋溶液对地下水造成潜在污染的最关键因子为Mn,其次是Fe.     

双柱固定原则在骨质疏松性AO 13C型骨折的临床应用和疗效分析

目的 运用双柱固定原则,手术治疗AO 13C型骨质疏松性骨折,评价患者肘关节重建情况及其功能。方法对本院骨科自2008年1月至2017年12月期间治疗的54例AO 13C型骨质疏松性骨折的患者进行回顾性分析,均采用切开复位肱骨远端解剖型LCP双钢板固定治疗。本组患者男21例,女33例;平均年龄(65.4±5.8)岁;根据AO/ASIF分型,13C1型21例,13C2型27例,13C3型6例;受伤至手术时间平均(7.9±1.6)d。用Mayo Clinic肘关节功能评分标准来评估手术疗效。结果 平均随访时间(20.8±2.1)个月。平均手术时间103.5min;平均骨折愈合时间(13.5±1.0)周。术后伸肘平均9.4°±5.6°,屈肘平均108.1°±7.4°,活动范围平均99.2°±10.3°。Mayo Clinic肘关节功能评估平均(84.7±8.1)分;优20例,良29例,中5例,差0例。结论 运用双柱固定原则,使用解剖型LCP治疗AO 13C型骨质疏松性骨折临床效果优良,肘关节功能恢复良好。