Evaluation of the commercial AD fosfomycin test for susceptibility testing of multidrug-resistant Enterobacterales and Pseudomonas aeruginosa

ObjectivesTo compare fosfomycin susceptibility testing with the commercial agar dilution (AD) test, AD Fosfomycin (Liofilchem, Roseto degli Abruzzi, Italy) and the reference AD method, using a collection of multidrug-resistant (MDR) Enterobacterales and Pseudomonas aeruginosa clinical isolates.MethodsThe collection included 119 carbapenemase-producing Enterobacterales, 53 Enterobacterales producing acquired AmpC-type and/or extended-spectrum β-lactamases and 38 carbapenemase-producing P. aeruginosa, including representatives of different high-risk clones. AD Fosfomycin and AD reference method (ISO 20776-1:2019) were performed starting from the same microbial suspension. Results were interpreted according to EUCAST clinical breakpoints (10.0). Essential agreement (EA), category agreement (CA) and error rates were calculated as described by the International Organization for Standardization.ResultsOf 172 Enterobacterales, 143 (83.1%, including 92.9% (52 of 56) of the NDM-producers and 84.2% (48 of 57) of the KPC-producers) were susceptible to fosfomycin using reference AD. A CA of 91.9% (158 of 172; 95% CI 87.1%–95.3%) and an EA of 92.5% (136 of 147; 95% CI 87.4%–96.0%), respectively, were calculated for the commercial AD Fosfomycin test, with 9.8% (14 of 143) of major errors and no very major errors (0 of 29). Overall, 86.8% (33 of 38) of P. aeruginosa showed a fosfomycin MIC ≤128 mg/L using reference AD. An EA of 84.8% (95% CI 66.3%–92.0%) was calculated for the commercial AD Fosfomycin test, with a CA of 100% (95% CI 93.6%–100%) when considering a tentative breakpoint at 128 mg/L.ConclusionsAD Fosfomycin showed an overall good concordance compared with reference AD.     

髋关节假体体外磨损试验的应用及研究进展

体外磨损试验(ISO 14242)基于良好的实验室控制条件和操作规范模拟人体行走步态的关节承受载荷和运动角度范围,广泛用于比较髋关节假体不同材料、假体设计的耐磨损性能。本文基于体外磨损试验和临床磨损评价的研究文献,介绍体外磨损标准试验方法及其在髋关节设计开发中的应用,探讨体外磨损标准方法的局限、研究进展以及未来发展方向。     

股骨头坏死动物模型评价方法的优缺点及展望

背景:股骨头坏死发病机制仍需要进一步研究,因此需要建立一个能够高度模拟人类股骨头坏死的动物模型,而如何正确评价股骨头坏死动物模型,是建立股骨头坏死动物模型的前提条件。目的:归纳总结近几年国内外对股骨头坏死动物模型的评价方法,综述各评价方法的优缺点,并探索新的评价方法,为动物模型的建立提供参考。方法:以“股骨头坏死,动物模型,评价方法”为检索词检索CNKI中国知网、万方、维普数据库,以“osteonecrosis of femoral head,femoral head necrosis,animal model,evaluation methods”为检索词检索PubMed、Web of Science及Medline数据库,检索2010年1月至2020年9月发表关于股骨头坏死动物模型评价方法的文献。结果与结论:①根据纳入标准通过阅读文献进行初步筛选,共获得51篇文章进行综述,其中中文文献33篇,英文文献18篇;②近年来,随着影像技术的发展和新技术的引入,股骨头坏死动物模型评估方法的选择增多,而选择合理的评价方式能减少建立动物模型过程中的工作量,并为后续研究提供参考,因此需要继续完善和改进。     

Association between ankle angle at initial contact and biomechanical ACL injury risk factors in male during self-selected single-leg landing

BackgroundIncreasing the ankle plantar-flexion angle at initial contact (IC) during landing reduces the impact features associated with landing, such as the vertical ground reaction force and loading rate, potentially affecting the risk of anterior cruciate ligament (ACL) injury. However, the relationships between the ankle plantar-flexion angle at IC and the previously identified biomechanical factors related to noncontact ACL injury have not been studied.Research questionThus, the purpose of this study was to determine whether significant relationships exist between the ankle plantar-flexion angle at IC and the biomechanical factors related to noncontact ACL injury.MethodsThe peak anterior tibial shear force, peak external knee valgus moment, peak knee valgus angle, and combined peak external knee valgus plus tibial internal rotation moments were measured in 26 individuals while performing self-selected, single-leg landing. Pearson correlation analyses were performed to assess the relationships between the ankle plantar-flexion angle at IC and the biomechanical factors mentioned above.ResultsThe greater ankle plantar-flexion angle at IC was related to smaller the peak knee valgus moment (r = −0.5, p = 0.009) and the combined peak knee valgus plus internal rotation moments (r = −0.58, p = 0.001).SignificanceThese results suggest that large ankle plantar-flexion angle at IC might be associated with lesser loading of the knee frontal plane and altering the self-selective ankle angle may result in biomechanical changes associated with ACL injury risk.     

人基质金属蛋白酶抑制剂Ⅰ原核核表达系统的构建及单克隆抗体的制备

目的 制备针对人基质金属蛋白酶抑制剂Ⅰ (TIMP-Ⅰ)融合蛋白的单克隆抗体.方法 用逆转录聚合酶链反应法从纤维化的肝组织中扩增TIMP-Ⅰ编码序列,产物克隆入pQE31载体,转化大肠埃希菌BL21,诱导表达后通过6×His标签进行纯化,用纯化后的蛋白免疫BALB/c小鼠,采用常规的细胞融合技术制备单克隆抗体,并进行鉴定.结果 成功构建了TIMP-Ⅰ原核表达体系,并获得了重组蛋白.筛选出4株能稳定分泌抗TIMP-Ⅰ的单克隆抗体杂交瘤细胞株,免疫球蛋白类型有3株为IgGl类.Western Blot印迹显示这些单抗能特异结合TIMP-1蛋白.结论 成功构建了人基质金属蛋白酶抑制剂Ⅰ原核表达体系,并获得了单克隆抗体.     

上下文效应对大学生面孔吸引力的影响

目的 研究上下文效应在大学生面孔吸引力的影响.方法 采用实验法对随机选取的唐山市3所高校的160名大学生单独进行实验处理,让被试对其所在组的照片上人物的面孔吸引力作出5维度等级评价,并用统计学方法对数据进行统计分析.结果 大学生实验组与对照组对一般吸引力的异性面孔照片评价存在显著性差异(x2=51.30,P＜0.01).不同性别的大学生在相貌评价过程中的影响存在显著差异(x2=11.06,P＜0.05).结论 大学生在评价面孔吸引力的过程中会受到上下文效应的影响.男性大学生在评价面孔吸引力的过程中比女性大学生更容易受到上下文效应的影响.     

基于单水平集函数的细胞分割算法

目的：由于细胞图像十分复杂,传统的基于像素或者边界的图像分割方法难以精确的实现细胞分割。因此,需要设计一种可以实现细胞图像精确分割的方法。方法：结合大津分割算法和主动轮廓模型的优点,设计出一种基于单水平集函数的细胞分割算法,首先对细胞图像大津分割,其结果作为水平集函数的初始值,然后使用迭代法对水平集函数演化。采用MATLAB对显微镜下获取的细胞图像进行试验,将本文改进后的算法与常规的算法进行了对比。结果：与传统的水平集分割算法相比,本文方法对细胞图像分割结果更加准确,迭代次数减少一半左右,因此分割时间也减少了一半左右。结论：结合细胞图像的结构特点,利用大津分割结果作为主动轮廓模型的初始值,可有效解决主动轮廓模型因为初始值设置不当导致的分割缺陷问题,水平集函数能够跟踪拓扑结构变化,具有计算精度高、算法稳定、优化边界清晰光滑等优点,在本文中得到了充分的应用。因此本文所提出的算法能够高效地实现细胞图像的分割。     

Influence of Cavity Designs on Fracture Behavior of a Mandibular First Premolar with a Severely Curved h-shaped Canal

IntroductionThis study aimed to investigate the fracture behavior of a mandibular first premolar with a severely curved h-shaped canal using the extended finite element method.MethodsFollowing the micro–computed tomographic data, models of the intact tooth, the conservative endodontic cavity (CEC), the modified conservative endodontic cavity (MCEC), and the traditional endodontic cavity (TEC) were created. All models were subjected with a total load of 600 N perpendicularly to the contact areas. The distributions of maximum principal stress were recorded. The evolution of cracks in the enamel and dentin was simulated with the extended finite element method.ResultsThe intact tooth showed the highest crack initiation load and the smallest stress concentration area. The CEC and MCEC showed higher crack initiation loads and smaller stress concentration areas compared with the TEC. On the occlusal surface, tensile stress was centralized around the distal fossa and the distal margins of cavities. In the root, the stress was concentrated at the mesiolingual side for all models and at the internal surface on the bifurcation section for the CEC. Cracks originated at buccal side of the distal fossa and microcracks were formed confined to the enamel, and then cracks occurred in the dentin below the bone level.ConclusionsFor the mandibular first premolar with a severely curved h-shaped canal, the MCEC preserved the fracture resistance equally as well as the CEC and reduced the stress concentration on the bifurcation section. The fracture initiated in the enamel, forming microcracks on the buccal side of the distal fossa and then occurred as an irreparable fracture in the dentin.     

比较两种方法在新生儿苯丙酮尿症筛查中的应用

目的比较串联质谱（tandemmassspectrometry,TMS）技术与茚三酮荧光法在苯丙酮尿症（phenylketonuria,PKU）筛查中的准确性。方法采用茚三酮荧光法对166247例PKU标本进行初筛,初查阳性标本均采用茚三酮荧光法和串联质谱技术复查,复查阳性者召回采血后统一再用上述两种方法进行检测,通过卡方检验统计比较两种方法的复查阳性率,探讨这两种方法在苯丙酮尿症筛查中的应用。根据血中Phe浓度进行鉴别诊断。结果（1）166247例新生儿初查阳性1152例,初查阳性率为6．93‰;（2）茚三酮荧光法和TMs技术的复查阳性率分别为14．58％、3．91％,两种方法比较具有统计学意义（P〈0．05）;（3）复查阳性者召回采血后统一再用上述两种方法进行检测,均确诊HPA3例,发病率为1：55415,其中经典型PKU2例,高苯丙氨酸血症1例。结论TMS技术能更快速、更准确地监测血苯丙氨酸水平,更适合用于PKU筛查,可有效地开展筛查的阳性召回工作及缓解家庭的精神压力。     

聚醚醚酮/羟基磷灰石/碳纤维复合材料的生物力学分析

目的利用有限元分析法比较聚醚醚酮/羟基磷灰石/碳纤维复合材料（75PEEK/10HA/15CF）与钛合金的生物力学。方法建立C4～C6有限元模型,于C5～C6间植入75PEEK/10HA/15CF或钛合金人工椎间盘和椎间融合器,计算在前屈、后伸、侧弯和旋转时临近椎体、椎间盘的wonMises应力变化和C5～C6节段的活动度及植入物上的应力分布。结果在正常情况下,钛合金人工椎间盘置换模型在前屈时C5椎体、C4~5椎间盘平均won Mises应力改变率分别为75PEEK/10HA/15CF人工椎间盘模型的1.50倍和1.67倍;在侧弯时C6椎体的平均won Mises应力改变率为75PEEK/10HA/15CF人工椎间盘置换模型的1.33倍。融合器模型,在前屈时C5椎体、C4~5椎间盘应力改变率前者为后者的1.48倍和1.87倍;在侧弯时C6椎体应力改变率,前者为后者的1.67倍。钛合金植入物的最大应力为75PEEK/10HA/15CF的4.5倍,并出现应力集中。结论与钛合金相比,75PEEK/10HA/15CF能更好地将负荷传递,增加融合率,能有效地减少临近椎体的应力,减少植入物沉降的发生。