Visual evoked potentials relating to imagery: Words for concrete objects versus absolute concepts

Summary We recorded visual evoked potentials (VEPs) elicited with high or low imaginable Chinese characters (HIC or LIC), representing concrete objects or absolute concepts, respectively. A closed circle (CC) acts as control stimulus. These were displayed (at 1.6° visual angle) for 35 ms on a TV monitor. Twenty-one channel VEPs (band-pas filter: 0.05–60 Hz), using balanced non-cephalic electrodes, were recorded from –100 to 924 ms for 11 right-handed male volunteers. The VEPs were analyzed by multivariate analysis of variance (MANOVA) and comparison of topographies at four remarkable peaks (P110, N160, P230 and N320). MANOVA showed significant differences (p< 0.001) for both conditions of channel and stimuli (HIC, LIC or CC). P100 for the CC-VEPs, N160 for the HIC-and LIC-VEPs, P230 for the CC-VEPs, and N320 for the HIC-VEPs were remarkable in the posterior scalp regions. Topographies at P100 and N160 showed no difference between the HIC-and LIC-stimuli. However, those at N320 showed difference between the HIC-and LIC-stimuli over the occipital and posterior temporal areas. Those results suggest that the responses at P100 and N160 might segregate Chinese characters from non Chinese characters. N320 suggested certain processes in imagery on recognizing Chinese characters over the occipital and posterior temporal areas.We are grateful to Dr. Yoshiji Kojima of Hamamatsu University for helpful comments.     

Folding and ligand recognition of the TPP riboswitch aptamer at single-molecule resolution

Thiamine pyrophosphate (TPP)-sensitive mRNA domains are the most prevalent riboswitches known. Despite intensive investigation, the complex ligand recognition and concomitant folding processes in the TPP riboswitch that culminate in the regulation of gene expression remain elusive. Here, we used single-molecule fluorescence resonance energy transfer imaging to probe the folding landscape of the TPP aptamer domain in the absence and presence of magnesium and TPP. To do so, distinct labeling patterns were used to sense the dynamics of the switch helix (P1) and the two sensor arms (P2/P3 and P4/P5) of the aptamer domain. The latter structural elements make interdomain tertiary contacts (L5/P3) that span a region immediately adjacent to the ligand-binding site. In each instance, conformational dynamics of the TPP riboswitch were influenced by ligand binding. The P1 switch helix, formed by the 5′ and 3′ ends of the aptamer domain, adopts a predominantly folded structure in the presence of Mg²⁺ alone. However, even at saturating concentrations of Mg²⁺ and TPP, the P1 helix, as well as distal regions surrounding the TPP-binding site, exhibit an unexpected degree of residual dynamics and disperse kinetic behaviors. Such plasticity results in a persistent exchange of the P3/P5 forearms between open and closed configurations that is likely to facilitate entry and exit of the TPP ligand. Correspondingly, we posit that such features of the TPP aptamer domain contribute directly to the mechanism of riboswitch-mediated translational regulation.     

What makes a structural intervention? Reducing vulnerability to HIV in community settings,with particular reference to sex work

Abstract

Increasing emphasis is being placed on the need for ‘structural interventions’ (SIs) in HIV prevention internationally. There is great variation in how the concept of SI is defined and operationalised, however, and this has potentially problematic implications for their likely success. In this paper, we clarify and elucidate what constitutes a SI with particular reference to the structured distribution of power and to the role of communities. We summarise the background to the growing emphasis being placed on the concept of SIs in HIV prevention policy, and present ethnographic case-study material from a sex worker's HIV project in Kolkata, India, to illustrate the nature of HIV vulnerability and its implications for the design and targeting of successful SIs. The paper draws attention to the dual importance of (1) attending to local complexities in the micro and macro-level structures that produce vulnerability; and (2) clarifying the meaning and role of communities within SIs.     

Periprosthetic fracture of the proximal tibia after lateral unicompartmental knee arthroplasty

We report a case of periprosthetic fracture of the proximal tibia after lateral unicompartmental knee arthroplasty following a trivial fall. At the time of surgery, the components were found to be loose; and there was a large uncontained tibial defect with bone loss and communition at the fracture site. The patient was treated by revision total knee arthroplasty and proximal structural tibial allograft, with a satisfactory result at 5-year follow up. Our case illustrates that a bone-conserving unicompartmental knee arthroplasty, if complicated by a periprosthetic fracture, can also present with a difficult surgical problem. Attention to preoperative planning and to availability of structural allograft for such difficult cases is recommended.     

Trabecular Bone Score and Hip Structural Analysis in Patients With Atypical Femur Fractures

Bisphosphonate use has declined dramatically in recent years, partly because of fear of rare side effects like atypical femur fractures (AFFs). It is therefore desirable to have a diagnostic method to identify those at risk of AFF to prevent this serious complication. We compared trabecular microarchitecture and hip geometry between 30 patients with AFF and 141 controls of similar age and sex, using bisphosphonates. Trabecular bone score (TBS) and hip structural analysis (HSA) were used to assess trabecular microarchitecture and macroscopic hip geometry from dual-energy X-ray absorptiometry images of the lumbar spine and hip, respectively. General characteristics, TBS, and HSA were compared between patients with AFF and controls using Student's t tests and chi-square statistics. Associations between AFF and TBS and femur geometric characteristics by HSA were adjusted for sex, age, height, weight, ethnicity, duration of bisphosphonate use, and glucocorticoid use. Additionally, the analysis of TBS was adjusted for lumbar spine bone mineral density and the time difference between dual-energy X-ray absorptiometry scanning and the diagnosis of AFF. Patients with AFF had significantly higher body mass index than controls, had used bisphosphonates longer, and glucocorticoids and proton pump inhibitors more frequently. Sex-specific T-score was significantly higher in patients with AFF at the lumbar spine (p?=?0.004), but not at the femoral neck (p?=?0.190) after adjustment for age, height, and weight. TBS did not differ significantly between patients with AFF and controls. Neither neck shaft angle nor any geometric variables at the femoral shaft measured by HSA differed between patients with AFF and controls. At the narrow neck, patients with AFF had lower buckling ratio and higher centroid position, consistent with a lower risk of classical fragility hip fractures. The findings at narrow neck and higher bone mineral density might be explained by the fact that the majority of patients with AFF used bisphosphonates to prevent glucocorticoid-induced osteoporosis. Based on our results, TBS and HSA do not appear to have value in detecting patients at risk of AFF.     

Social support and individual styles of coping in the Japanese workplace: an occupational stress model by structural equation analysis

The aim of the present study was to ascertain the role of social support and individual styles of coping on employee well‐being. The subjects were intermediate managers working for a zipper and sash manufacturing company in Japan. Measurements were made of the following: depression using the Self‐rating Depression Scale (SDS), job demand, job control, social support using Karasek's Job Content Questionnaire, and of three coping styles: emotion‐oriented coping, task‐oriented coping and avoidance‐oriented coping using the Coping Inventory for Stressful Situations (CISS). Data was analysed by structural equation modeling. Each coping style had a direct effect on depression. Emotion‐oriented coping had a negative effect. On the other hand, task‐oriented coping and avoidance‐oriented coping had a positive effect. Moreover, there was an indirect effect that coping styles precede and determine the perception of social support as well as job demand and control. Social support showed a direct positive effect on depression. However, the overall impact on employee well‐being was greater for individual coping styles as compared to social support from either supervisors or co‐workers. The present study showed the effectiveness of coping strategies in the workplace. Copyright © 2003 John Wiley & Sons, Ltd.     

生育保险病种费用影响因素结构方程模型分析

目的:研究生育保险病种费用影响因素,为生育保险按病种付费提供依据.方法:抽取南京市4家医院2002/2004生育保险参保人员病历首页以及财务结算帐单1525份,用结构方程模型(SEM)方法分析.结果:临床特征、医护质量和社会经济特征三个隐变量对住院费用的影响系数分别为0.9334,0.3194,0.2230,病种临床特征对住院费用影响最大.结论:结构方程模型分析生育保险病种住院费用影响因素收到很好的效果.     

客观结构化考试在学生中医临床能力考核中的应用

目的对客观结构化临床考试在中医药高等专科学校各专业临床诊疗能力考核中应用的可行性进行探讨。方法设立以标准病人、模拟病人、模拟工具及电脑模拟等多种形式的系列考站,对在校中医临床、针灸推拿等专业临床各科课程结束的技能考核和实习前技能总考核采用客观结构化考试方法,初步观察并分析考核结果的信度与效度。结果客观结构化临床考试结果具有较高的信度和效度。结论中医客观结构化临床考试在评价学生中医诊疗临床能力方面具有标准化、客观化和结构化3大基本特点。