A combination of digital design and three-dimensional printing to assist treatment of thoracolumbar compression fractures using percutaneous kyphoplasty

Objective:To evaluate the clinical efficacy of the preoperative digital design combined with three-dimensional(3D) printing models to assist percutaneous kyphop...     

Early Age Shrinkage and Mechanical Effect of Ultra-High-Performance Concrete Composite Deck: A Case Study with In Situ Test and Numerical Simulation

For the Honghe Bridge project located in Yunnan Province, Southwest China, a steel/ultrahigh-performance concrete (UHPC) composite deck is used in the suspension bridge with a 700 m main span, and the steel stud connectors are used in the 50 mm–thick UHPC layer. To investigate the shrinkage behavior of UHPC and the relevant influence, the in situ time-dependent strain is measured continuously, and within the 20-day curing time, the material behavior is summarized based on test results. This paper proposes a prediction model for UHPC shrinkage which is refined from the widely used B3 model for normal concrete material, and the parameter values are modified and optimized by experimental comparison. Combining the numerical model and the finite element analysis model of the composite deck, the detailed mechanical state in structural parts is studied. For the practical construction, the simulation results indicate that the small thickness of UHPC above the stud and weak bond strength can influence the eventual structural performance greatly. In the discussion of stress distribution at different locations of the deck, the potential crack on the edge and the corner of the UHPC–steel interface and the mechanical damage on the stud connector around are also indicated.     

Study on Hot Deformation Behavior of an Antibacterial 50Cr15MoVCu Tool Steel

Hot deformation behaviors of an antibacterial 50Cr15MoVCu tool steel were studied. The flow stress curves presented three typical characteristics: (i) a single peak dynamic recrystallization curve, (ii) a monotone incremental work-hardening curve, and (iii) the equilibrium dynamic recovery curve. The flow stress increased with the increase of the deformation rate at each deformation temperature and decreased with the increase of the deformation temperature at the same deformation rate. The thermal activation energy and material constants were Q of 461.6574 kJ/mol, A of 3.42 × 10¹⁷, and α of 0.00681 MPa⁻¹, respectively. The high temperature constitutive equation was: Z=ε˙expQ/RT=3.42×1017sinh0.0068×σ5.6807. Based on the processing maps and microstructure evolution, the best hot working process was a deformation temperature of 1050 °C and deformation rate of 0.001 s⁻¹.     

A Numerical Measurement Method for Dynamic Granular Materials Based on Computer Vision

Granular materials are widespread in nature and human production, and their macro-mechanical behavior is significantly affected by granule movement. The development of computer vision has brought some new ideas for measuring the numerical information (including the amount of translation, the rotation angle, velocity, acceleration, etc.) of dynamic granular materials. In this paper, we propose a numerical measurement method for dynamic granular materials based on computer vision. Firstly, an improved video instance segmentation (VIS) network is introduced to perform end-to-end multi-task learning, and its temporal feature fusion module and tracking head with long-sequence external memory can improve the problems of poor video data quality and high similarity in appearance of granular materials, respectively. Secondly, the numerical information can be extracted through a series of post-processing steps. Finally, the effectiveness of the measurement method is verified by comparing the numerical measurement results with the real values. The experimental results indicate that our improved VIS obtains an average precision (AP) of 76.6, the relative errors and standard deviations are maintained at a low level, and this method can effectively be used to measure the numerical information of dynamic granular materials. This study provides an intelligent proposal for the task of measuring numerical information of dynamic granular materials, which is of great significance for studying the spatial distribution, motion mode and macro-mechanical behavior of granular materials.     

Risk factors of young males with physically demanding occupations having accumulated damage of anterior cruciate ligament

ObjectiveTo present the clinical characteristics of accumulated anterior cruciate ligament (ACL) damage among young male patients undergoing routine exercise, and to evaluate the related risk factors.MethodsA retrospective study involving ACL‐accumulated damage from June 2015 to December 2019 was conducted. Baseline characteristics, such as age, body mass index (BMI), training parameters, and clinical signs, were recorded. The results of the radiologic examinations and related standardized tests were obtained to evaluate the research outcomes. These results were compared using Student''s t‐test or Chi‐square test, and the impact of risk factors on the patient''s injury were analyzed.ResultsA total of 86 men with accumulated ACL damage were included in this study. Exercise pain (86 [100%]), synovitis (80 [93.0%]), and intra‐articular effusion (79 [91.9%]) were the most common clinical symptoms. Loosening of ligaments, decreased tension, mild hyperplasia, and intercondylar fossa effusion were observed using radiography, magnetic resonance imaging, and arthroscopy. Age, BMI, training intensity, length of training, and knee hyperextension were identified as risk factors for accumulated ACL damage.ConclusionThis study suggests that accumulated ACL damage has differentiated clinical symptoms, imaging features, and risk factors compared to common ACL injuries.     

重庆地区梅毒螺旋体基因分型及其临床相关性研究

目的：调查重庆地区梅毒螺旋体基因亚型的分布,初步探讨基因亚型与临床相关性。方法：收集2010年6月至2013年10月重庆地区421例梅毒标本,用巢式PCR检测梅毒螺旋体DNA多聚酶I基因（DNA polymerase I gene,polA）,然后扩增阳性标本酸性重复蛋白基因（acid repeat protein,arp）和苍白密螺旋体重复家族基因（treponema pallidum repeat,tpr）及TP0548基因,分别根据Pillay标准基因分型和三基因分型法进行分型,利用双侧Fisher’s exact test进行数据统计分析,初步探讨不同基因亚型与血清固定、梅毒复发和吉海反应的相关性。结果：163例标本polA PCR检测阳性,arp、tpr基因和TP0548基因亚型分别以14型、d型和f型为主。正规驱梅治疗12月后,32例患者血清固定,其中tpr基因d型（1１例）、a和b型（各2例）和f型（1例）;3例患者梅毒复发,其中TP0548基因c型（2例）和f型（1例）;8例发生吉海反应,其中14f/f（4例）,14d/f（3例）和未分型（1例）。结论：重庆地区梅毒螺旋体以14、d和f型为优势型。梅毒血清固定可能与tpr基因b型相关,14f/f基因型的二期梅毒患者易发生苄星青霉素治疗后的吉海反应。     

迷走神经刺激结合电针对条件线索诱导觅药行为的干预作用及其分子生物学机制

目的:观察迷走神经刺激(vagus nerve stimulation,VNS)结合电针疗法对条件性线索诱导的大鼠海洛因觅药行为的影响,揭示其作用的分子生物学机制,为临床抗复吸提供实验依据.方法:应用固定比率程序(fixed ratio,FR)1建立大鼠海洛因自身给药模型,随机分为3组:电针(electroacqupuncture)组、VNS组及VNS结合电针组,每组6只.处理30 min,每天1次,连续10 d.用条件性线索诱导海洛因觅药行为,观察上述方法对条件性线索诱导的觅药行为的影响.用Western blotting方法检测各组伏隔核(NAc)、前额皮层(PFC)等相关脑区△FosB蛋白表达.结果:迷走神经弱刺激结合电针处理后使条件线索诱导的有效鼻触数比电针组及VNS组显著减少(P＝0.019,P＝0.006).迷走神经激结合电针处理后大鼠自由活动度较VNS组显著增多(P＝0.032).迷走神经刺激结合低频弱电针组大鼠NAc中△fosB表达较电针组和VNS组均显著减少(P＝0.000,P＝0.001).该组CPU中△fosB的表达较电针组显著减少(P＝0.001).该组NTS中的表达较与电针组和VNS组均显著增加(P＝0.000,0.000).结合组的PFC、BST中△fosB表达较电针组显著增多(P＝0.000,0.016).结论:电针结合迷走神经刺激可减少大鼠的觅药行为,增加其活动度.作用的机制部分可能是通过调节一些脑区△FosB蛋白表达以激活上行通路强化前额皮层功能,从而削弱VTA-NAc奖赏通路的长时程适应.     

针刺治疗2型糖尿病100例疗效观察

目的　观察针刺治疗糖尿病的疗效。方法　对 10 0例患者在适当饮食控制的基础上 ,电针脾俞、肾俞、肺俞、胃脘下俞、足三里、内关、三阴交、合谷、血海 ,并辨证加减。结果　治疗后患者空腹血糖值下降 ,与治疗前比 ,P<0 .0 5 ,有显著差异 ;症状明显者由治疗前的 85 %下降到治疗后的 4 %。结论　针刺能降低糖尿病患者空腹血糖 ,在改善临床症状方面亦有明显效果。     

中西医结合高等本科教育的思考

中西医结合高等本科教育自1991年广州中医药大学在七年制中医学专业中开设中西医结合临床医学方向起步,至今已有15年的历程.在这个发展历程中,中西医结合高等本科教育取得了有目共睹的成就.但是目前中西医结合本科教育的发展还远远滞后于社会需要,为此,我们必须认清现状,把握机遇,勇于挑战,促进中西医结合教育事业及整个中西医结合事业长足发展.