Modeling individualized coefficient alpha to measure quality of test score data

Individualized coefficient alpha is defined. It is item and subject specific and is used to measure the quality of test score data with heterogenicity among the subjects and items. A regression model is developed based on 3 sets of generalized estimating equations. The first set of generalized estimating equation models the expectation of the responses, the second set models the response's variance, and the third set is proposed to estimate the individualized coefficient alpha, defined and used to measure individualized internal consistency of the responses. We also use different techniques to extend our method to handle missing data. Asymptotic property of the estimators is discussed, based on which inference on the coefficient alpha is derived. Performance of our method is evaluated through simulation study and real data analysis. The real data application is from a health literacy study in Hunan province of China.     

何首乌致肝损伤大鼠的动态血清代谢组学研究

该文采用液相色谱-质谱方法测定服用何首乌大鼠的血清代谢指纹谱,同时利用多元统计分析方法比较代谢谱差异并筛查显著相关的生物标志物,考察其动态变化趋势。探讨何首乌致大鼠肝脏损伤的代谢组学动态变化,寻找其显著相关的生物标志物,并考察标志物的动态变化趋势,以期为何首乌致肝损伤的内在机制与临床早期诊断提供依据。结果显示给药后不同时间点大鼠的血清代谢轮廓存在一定的差异,经比较分析,共筛选得到6个潜在生物标志物:oleamide,lyso PC(16∶0),leukotriene A4,trans-tetra-dec-2-enoic acid,dihydrocortisol和7a-hydroxydehydroepiandrosterone,这些标志物在何首乌致肝损伤动态过程中呈现一定的变化趋势。所筛选到的生物标志物在给药1周后含量即出现明显变化,相比于ALT,AST来说更加敏感。一定程度上可揭示出何首乌造成肝损伤的动态机制以及肝脏自我修复表现,对于监测服用何首乌患者肝功能、早期发现何首乌肝损伤具有潜在的应用价值和意义。     

Relationship between functional disc position and mandibular displacement in adolescent females: posteroanterior cephalograms and magnetic resonance imaging retrospective study

The purpose of this study was to investigate the relationship between the disc positions of temporomandibular joints (TMJ), the vertical and lateral mandibular displacement (VMD and LMD, respectively) and age in female adolescents with signs and symptoms of the temporomandibular disorders (TMD). The VMD and LMD were assessed, using posteroanterior (PA) cephalograms. The disc positions were assessed by magnetic resonance imaging (MRI) and categorized as follows: normal disc position, functional disc displacement and functional disc dislocation. Excluding patients with osteoarthritis, the total number of subjects was 54 female adolescents who were grouped into three: the bilateral normal disc position group, the unilateral or bilateral functional disc displacement group, and the unilateral or bilateral functional disc dislocation group. We compared the extent of VMD and LMD between the three groups, and investigated their correlation with age. Results indicate that functional disc displacement and dislocation are related to mandibular displacement, and VMD did not correlate with age but LMD did correlate with age. This study suggests that the onset of disc displacement is related to the mandibular displacement and disturbs normal growth of the mandible three-dimensionally.     

24例髁突骨折经下颌后进路行坚强内固定的疗效观察

目的:介绍发生于髁突颈和髁颈以下髁突骨折用小型钛板经下颌后进路行解剖复位、坚强内固定术的方法和经验。方法:发生于髁突颈和髁颈以下骨折24例30侧,经下颌后进路以小型钛板行坚强内固定术。术后3～6个月后复查并评价疗效,复查内容包括:张口度、张口型、咬合关系、X线表现、面神经损伤情况。结果:张口度较术前明显增大,张口型偏移明显改善,错牙合3例,面神经下颌缘支损伤2例。X线检查:髁突骨折复位良好,髁突无移位。结论:下颌后进路是一种治疗髁突颈和髁颈以下骨折的有效方法。     

颧上颌复合体骨折的诊断与治疗

颧上颌复合体是面部最突出的部位之一,由于其解剖部位的特殊性,颧上颌复合体骨折在面中部骨折中占有相当大的比例。骨折后不仅引起局部凹陷畸形,甚至导致开口受限、复视等功能障碍。作者结合文献复习和临床经验,对颧上颌复合体骨折的原因、临床表现、治疗方法、手术入路和术后并发症等进行了讨论。认为眉侧切口联合口内切口入路,可以避免冠状切口的种种弊端。此法可在直视下开放复位,较好地暴露颧骨、上颌骨连接处及眶下区骨折,切断颧骨咬肌附丽,松解颧骨骨折块,再进行内固定,效果良好。手术后瘢痕小,面神经功能无损伤,外形及功能恢复良好,值得推广。     

Clinical study of the internal gaps of zirconia and metal frameworks for fixed partial dentures

The aim of this clinical study was to compare the internal gaps between abutment teeth and posterior fixed partial dentures (FPDs) fabricated utilizing milled zirconia and cast gold-alloy frameworks. As part of an ongoing randomized controlled clinical trial, 32 three-unit FPDs (16 zirconia and 16 metal-ceramic) in 25 patients were randomly selected for adaptation measurements. During the bisque-stage ceramic try-in, an A-silicone impression material was placed between the abutment teeth and the framework. The internal gap, corresponding to the thickness of the replica, was measured under magnification at the following locations: cervical, axial, and occlusal (cusp-tips and central). The internal gaps of FPDs with zirconia frameworks were significantly larger in cervical, axial, and centro-occlusal regions (cervical: 189.6 ± 71.8  μ m vs. 118.6 ± 31.5  μ m; axial: 140.5 ± 38.3  μ m vs. 95.7 ± 18.1  μ m; and centro-occlusal: 192.0 ± 66.5  μ m vs. 153.1 ± 69.8  μ m). The cervical gaps next to the pontics were significantly larger compared with those of the outer walls in both types of FPDs (zirconia: mean difference 67.7 ± 114.7  μ m; metal-ceramic: mean difference 30.0 ± 71.2  μ m). Posterior three-unit FPDs incorporating milled zirconia frameworks exhibited larger internal gaps than those constructed using conventional metal-ceramic techniques.     

Prognosis of permanent teeth with internal resorption: a clinical review

Abstract This study was performed in order to report the clinical features of internal resorption cases and evaluate their prognosis after endodontic treatment. Twenty-seven patients with 28 teeth with internal resorption were referred to our clinic and 20 teeth were treated endodontically. Sixteen teeth had non-perforating internal resorption and were treated by conventional root canal therapy. The remaining 4 teeth had perforating internal resorption and were initially treated by remineralization therapy with calcium hydroxide. The teeth treated by conventional root canal therapy showed clinical and radiographic evidence of healing. However, the remineralization therapy was successful in only one case. The three failed cases were subsequently treated by endodontic surgery. The surgical therapy was unsuccessful in one case due to extensive loss of marginal alveolar bone and increased tooth mobility.     

钛板坚强内固定治疗下颌骨骨折136例报告

目的：总结钛板坚强内固定术治疗下颌骨骨折的临床疗效。方法：收集1998～2004年136例下颌骨骨折病例，行钛板坚强内固定术治疗，分别在手术后1个月、3个月、6个月复查，拍摄X线片，观察骨折线对位愈合情况、咬合关系及开口度等功能恢复情况。结果：136例中134例一期愈合，2例延期愈合。X线片示骨折线对位良好，咬合关系及开口度均恢复良好。结论：钛板坚强内固定术治疗下颌骨骨折效果好，方法可靠，操作简单。     

冠状切口在颧骨复合体骨折中的应用

目的探讨颧骨复合体骨折复位和固定术中应用冠状切口入路的手术适应证、手术方法及减少并发症的措施。方法84例颧骨复合体骨折的患者应用单纯冠状切口为36.9%、冠状切口 下睑缘切口为32.1%、冠状切口 下睑缘切口 前庭沟切口为16.7%和冠状切口 前庭沟切口为14.3%。术中患者均使用微型钛板或小型钛板坚强内固定。对于眶底骨折出现眼球内陷的患者以羟基磷灰石人工骨进行眶底重建。结果84例患者均未发生手术后切口感染,术后随访3个月到2年,无面神经永久性损伤,术后所有咬合关系紊乱的患者均达到功能性咬合。通过训练后张口度得到满意恢复。8例患者术后患侧颧弓处仍稍显膨隆。术后眼球内陷只有1例仍大于3mm,其余均恢复满意。结论颧骨复合体骨折使用头皮冠状切口时,熟练掌握颞部的解剖层次是至关重要的,仔细保护神经及血管结构可减少手术并发症。     

不同形状小型钛板在髁突骨折固定中的效果评价

目的评估3种不同形状小型钛板固定髁状突颈骨折的临床效果。方法回顾分析采用1块小型钛板治疗22例29侧髁状突颈骨折患者,其中用I形钛板固定10侧,L形钛板固定8侧,X形钛板固定11侧。结果在应用I板或L形板固定的病例中,2侧出现螺钉松动,5侧出现骨折段移位。而在应用X形板固定的病例中,未出现螺钉松动和骨折段的移位。结论应用1块X形钛板行髁状突颈骨折内固定,不仅具有双板的固定效果,而且有创伤相对较小,手术时间相对减少,节省费用等优点。