Electrocortical dynamics differentiate athletes exhibiting low- and high- ACL injury risk biomechanics

Anterior cruciate ligament (ACL) injuries are physically and emotionally debilitating for athletes,while motor and biomechanical deficits that contribute to ACL injury have been identified, limited knowledge about the relationship between the central nervous system (CNS) and biomechanical patterns of motion has impeded approaches to optimize ACL injury risk reduction strategies. In the current study it was hypothesized that high-risk athletes would exhibit altered temporal dynamics in their resting state electrocortical activity when compared to low-risk athletes. Thirty-eight female athletes performed a drop vertical jump (DVJ) to assess their biomechanical risk factors related to an ACL injury. The athletes' electrocortical activity was also recorded during resting state in the same visit as the DVJ assessment. Athletes were divided into low- and high-risk groups based on their performance of the DVJ. Recurrence quantification analysis was used to quantify the temporal dynamics of two frequency bands previously shown to relate to sensorimotor and attentional control. Results revealed that high-risk participants showed more deterministic electrocortical behavior than the low-risk group in the frontal theta and central/parietal alpha-2 frequency bands. The more deterministic resting state electrocortical dynamics for the high-risk group may reflect maladaptive neural behavior—excessively stable deterministic patterning that makes transitioning among functional task-specific networks more difficult—related to attentional control and sensorimotor processing neural regions.     

Patterns of peer tutoring in nursing

Peer tutoring in higher education is an effective strategy for promoting academic gains. Within nursing, peer tutoring has been used in the clinical setting, but little information is available regarding its use across the nursing curriculum. A peer tutoring program was created at a regional Appalachian university to meet the needs of students with poor academic backgrounds and multiple risk factors for failure. As the program naturally evolved, students moved beyond the time-honored one-on-one model. Many tutoring patterns developed including dyad, small group, large group, skill based, assignment based, and question based. Qualitative evaluation data from the program revealed that each pattern required different tutor skills, involved varied tutor-tutoree relationships, focused on different outcomes, and had certain advantages and disadvantages. All tutoring patterns contributed to improved academic skills and performance.     

髋关节置换术后人工假体周围早期骨量变化的连续观察

目的:连续观察髋关节置换术后人工假体周围早期骨量变化,为假体技术完善和骨量丢失的药物预防提供依据。方法:选择2004-01/2006-01在商丘市第一人民医院骨科住院进行人工髋关节置换术患者55例,均在术后1周、3、6和12个月时用双能X线骨密度仪进行人工假体周围骨量测定(髋臼假体区,采用Wilkinson4区法,即R1、R2、R3、R4区;股骨柄假体区,采用Gruen方法分7个测量兴趣区,即ROI①、②、③、④、⑤、⑥和⑦区),上述采集数据与同一患者未置换部位比较。结果:55例患者均进入结果分析。①髋臼区骨密度:髋臼区术侧与健侧术后1周检查时各扫描区域骨密度检测值分布接近(P均>0.05),但在术后3、6和12个月检查中,术侧R1、R2和R3区骨密度全部测试结果均明显低于健侧同部位检测值(P均<0.05～0.01),两侧间R4区骨密度测试结果无明显区别(P>0.05)。②股骨区骨密度:术后1周时术侧各扫描区域骨密度检测值与健侧分布接近(P均>0.05),在术后3、6和12个月检查中,术侧ROI①、②、③、⑥和⑦区骨密度全部测试结果均明显低于健侧同部位检测值(P均<0.05～0.01),两侧间ROI④和⑤区骨密度大部分测试结果无明显区别(P均>0.05)。结论:髋关节置换术患者人工假体周围早期骨量丢失以R1、R2、R3区和ROI①、②、③、⑥、⑦区较为明显,并多发生术后3～12个月。     

心理理论中的规则理论

目的:心理理论现有的规则理论是"认知复杂及控制理论"与"关系复杂理论",通过对这两个理论的比较、分析,意图对个体心理理论能力发展做深入探讨。资料来源:应用计算机检索Elsevier数据库和CNKI数据库1996/2005相关文章,检索词为"theroy of mind,rule,cognitivecomplexity,relational complexity,心理理论,规则"。资料选择:选择阐述"认知复杂及控制理论"与"关系复杂理论"的文章,排除重复文章。资料提炼:共检索到47篇关于心理理论的规则理论方面的文献,纳入33篇。资料综合:认知复杂及控制理论将执行上的失败归因于缺少对规则的反思,而不是归因于缺少对规则的意识;关系复杂理论通过概念组块和分段法降低加工负荷,它对变量进行压缩处理。关系复杂理论中的概念组块和认知复杂及控制理论中的反思来自于不同的方向,概念组块可以认为是来自通过组块对工作记忆负担的减轻,进而对复杂性程度的降低;而反思是个体本身对规则的再认识,这一过程又受到诸多因素的影响才能从多个简单规则整合成一个规则。关系复杂理论和认知复杂及控制理论都能够对心理理论任务进行解释,而真正非实验条件下的心理理论任务就需要更多的考量因素。结论:当面对多样性和层次性的心理理论任务时,这两个理论所作出的自上而下的"反思"与自下而上的"组块"有必要整合起来,形成解决任务的整合规则。     

利用激光扫描与CAD-CAM技术进行面部三维重建

目的:为临床医学个体化三维建模需要,提出用激光扫描仪与计算机辅助设计与制造技术反求面部表面轮廓的方法。方法:采用激光扫描系统对人体面部石膏模型进行扫描,通过获得的点云文件建立面部三维模型,将三维模型同原始点云数据进行偏差分析。结果:对由不同数量曲面片重建的模型与原始点云进行比较分析,精度可达0.01～0.20mm,最大误差主要集中在面部曲率较大处,结果满足整形设计的临床需求。结论:利用激光扫描与CAD/CAM技术进行面部三维模型重建,可以满足整形设计的临床需求。     

脑源性神经营养因子基因修饰的人脐血干细胞移植对损伤脊髓组织的保护

目的:观察损伤脊髓组织经脑源性神经营养因子基因修饰的人脐血干细胞移植后,细胞内环境的改善及下肢运动功能、电生理指标的变化。方法:实验于2005-10/2006-09在广东医学院实验动物中心完成。①选取清洁级SD大鼠96只,随机数字表法分为4组:基因修饰细胞移植组、单纯细胞移植组、损伤对照组、正常对照组,24只/组。新鲜脐带血来源于广东医学院妇产科健康产妇,产妇及其家属均知情同意。脑源性神经营养因子的DNA由解放军第二军医大学提供。②基因修饰细胞移植组、单纯细胞移植组、损伤对照组大鼠制备脊髓半横断损伤模型,无菌条件下显露T7～9棘突及椎板,暴露T8平面脊髓,用弯刀将左侧半脊髓横向切断,再用负压吸引器吸除脊髓组织,形成一个2mm×2mm×2mm的间隙。③采集人脐血单个核细胞,以1×109L-1密度接种于含10mLDMEM/F12的培养皿中,同时以终浓度5μmol/L的Brdu标记,置于含体积分数为0.05的CO2细胞培养箱中,48h后磷酸盐缓冲液反复离心洗涤,制备密度为6×109L-1的人脐血干细胞悬液,进行脑源性神经营养因子DNA质粒的提取、鉴定、纯化,转染。④将转染的人脐血干细胞悬液重悬为2.5×1010L-1,取3μL浸透在与宿主脊髓损伤间隙大小一致的明胶海棉上,并将其植入基因修饰细胞移植组大鼠脊髓损伤处,确认植入后缝合硬脊膜、肌层及皮肤。单纯细胞移植组单纯植入含2.5×1010L-1高纯化的人脐血干细胞3μL的明胶海绵。损伤对照组仅植入明胶海绵。⑤移植术后24h,每组取8只大鼠进行脊髓水肿程度及离子含量检测。移植术后6,12周,每组各取8只大鼠以爬坡试验检测其下肢运动功能情况,并采用颅刺激法检查运动诱发电位。结果:各组24只SD大鼠均进入结果分析。①脊髓水肿程度及离子含量:脊髓损伤后组织水肿及Na 、Ca2 含量升高,K 、Mg2 含量降低,经脑源性神经营养因子基因修饰的人脐血干细胞脊髓内移植后可显著改善上述指标。与损伤对照组比较,基因修饰细胞移植组脊髓含水量及Na 、Ca2 含量显著降低(t=1.77～1.79,P均<0.05),K 、Mg2 含量升高(t=2.05～2.41,P均<0.05)。②下肢运动功能评估:移植术后6周,除正常对照组外各组大鼠左下肢均瘫痪,爬坡试验为0级。移植术后12周,基因修饰细胞移植组大鼠肌力恢复至Ⅱ级,单纯细胞移植组恢复至Ⅰ级。损伤对照组0级。③电生理检查:移植术后6周,基因修饰细胞移植组记录到运动诱发电位,而单纯细胞移植组、损伤对照组未记录到。术后12周,基因修饰细胞移植组、单纯细胞移植组大鼠均记录到运动诱发电位,但与基因修饰细胞移植组比较,单纯细胞移植组运动诱发电位潜伏期延长,波幅降低;损伤对照组仍未记录到运动诱发电位。结论:脑源性神经营养因子基因修饰的人脐血干细胞脊髓内移植对脊髓损伤起保护作用,其机制可能与减少神经细胞离子失衡、改善细胞内环境有关。     

Evaluation of the Interferon‐γ Assay on Blood Collected at Exsanguination of Cattle Under Field Conditions for Surveillance of Bovine Tuberculosis

Development of point of concentration (POC) surveillance strategies for bovine tuberculosis (bTB) would facilitate global efforts to eradicate bTB. The interferon‐gamma (IFNγ) assay can detect IFNγ responses to Mycobacterium bovis in blood collected at commencement of exsanguination (COE) of experimentally challenged cattle but has not been evaluated under field conditions. The current study was aimed at determining (i) whether blood collected at COE of cattle at slaughter, under field conditions, is practical to obtain and useful for identifying cattle as IFNγ positive for bTB, (ii) whether the results of the IFNγ assay obtained at COE reliably compare with results obtained from live animals in the field, and (iii) whether the identified animal(s) originated from bTB‐infected or bTB‐exposed herds. Cattle from three risk groups were used: the highest risk group consisted of 49 cattle from 3 bTB‐infected herds; the medium risk group consisted of 24 cattle from a potentially exposed herd; and the lowest risk group consisted of 60 cattle from herds with no known history of bTB exposure. The IFNγ assay was performed on blood collected both before stunning and at COE of cattle at slaughter. An enhanced slaughter inspection for gross lesions consistent with bTB was performed on all cattle. In addition, lymph nodes were cultured for M. bovis for cattle that tested positive for bTB via the IFNγ assay and for most cattle that tested negative for bTB. Cattle, both with and without lesions consistent with bTB, were identified as positive for bTB by the IFNγ assay using blood collected at COE, but none of the positive cattle originated from the lowest risk group. The current study demonstrates that blood collected at COE of cattle is both a practical and moderately reliable sample for accessing bTB infection using the IFNγ assay.