Selecting those to refer for joint replacement: Who will likely benefit and who will not?

Osteoarthritis (OA) is one of the 10 most disabling diseases in developed countries and worldwide estimates are that 10% of men and 18% of women aged over 60 years have symptomatic OA, including moderate and severe forms. Total joint replacement (TJR) is considered the most effective treatment for end-stage OA in those who have exhausted available conservative interventions. The demand for TJR is continually rising due to the ageing population; in the United States, more than 1 million TJRs were performed in 2010 and the number of procedures is projected to exceed 4 million in the US by 2030. It has been estimated that of all hip and knee replacements performed, approximately one quarter of the patients may be considered inappropriate candidates. Predicting who will benefit from TJR and who will not would seem critical in terms of containing the current and projected expenditure as well as improving satisfaction in TJR recipients. Few formal predictive tools are available to aid referring clinicians to determine those likely to be good or poor responders to surgery and current available tools tend to focus on disease severity alone with little consideration of risk factors that may predict a poor outcome or impede an effective response to surgery. This review examines the tools available to assist with assessing appropriateness for TJR; investigates the modifiable risk factors associated with poor outcome; and identifies areas for future research in selecting those appropriate for joint replacement.     

Vigabatrin pediatric dosing information for refractory complex partial seizures: Results from a population dose–response analysis

We predicted vigabatrin dosages for adjunctive therapy for pediatric patients with refractory complex partial seizures (rCPS) that would produce efficacy comparable to that observed for approved adult dosages. A dose–response model related seizure‐count data to vigabatrin dosage to identify dosages for pediatric rCPS patients. Seizure‐count data were obtained from three pediatric and two adult rCPS clinical trials. Dosages were predicted for oral solution and tablet formulations. Predicted oral solution dosages to achieve efficacy comparable to that of a 1 g/day adult dosage were 350 and 450 mg/day for patients with body weight ranges 10–15 and >15–20 kg, respectively. Predicted oral solution dosages for efficacy comparable to a 3 g/day adult dosage were 1,050 and 1,300 mg/day for weight ranges 10–15 and >15–20 kg, respectively. Predicted tablet dosage for efficacy comparable to a 1 g/day adult dosage was 500 mg/day for weight ranges 25–60 kg. Predicted tablet dosage for efficacy comparable to a 3 g/day adult dosage was 2,000 mg for weight ranges 25–60 kg. Vigabatrin dosages were identified for pediatric rCPS patients with body weights ≥10 kg.     

Point process modelling of the Afghan War Diary

Modern conflicts are characterized by an ever increasing use of information and sensing technology, resulting in vast amounts of high resolution data. Modelling and prediction of conflict, however, remain challenging tasks due to the heterogeneous and dynamic nature of the data typically available. Here we propose the use of dynamic spatiotemporal modelling tools for the identification of complex underlying processes in conflict, such as diffusion, relocation, heterogeneous escalation, and volatility. Using ideas from statistics, signal processing, and ecology, we provide a predictive framework able to assimilate data and give confidence estimates on the predictions. We demonstrate our methods on the WikiLeaks Afghan War Diary. Our results show that the approach allows deeper insights into conflict dynamics and allows a strikingly statistically accurate forward prediction of armed opposition group activity in 2010, based solely on data from previous years.     

MRTA对三叉神经痛患者微血管减压术后疗效的预测

目的:评价磁共振体层血管成像(MRTA)对预测三叉神经痛患者微血管减压术(MVD)后疗效的价值.方法:277例行MVD的三叉神经痛患者手术前、后接受MRTA检查,由2名影像医师分别读取术前及术后NVC分级,术后疗效分为优、良和差3组,采用SPSS 13.0软件包中的x2检验确定术前NVC的压迫程度、术后NVC压迫程度和术后NVC的缓解度在3组的分布有无差异.结果:250例(90.2％)病例术后2年疗效为优,18例(6.5％)为良,8例(2.9％)为差,1例(04％)因术后颅内出血死亡.术前不同NVC分级的病例,术后疗效无显著差异(x2=5.542,P=-0.476);术后不同NVC分级(x2=18.693,P＜0.05)和不同NVC缓解度(x2=11.484,P＜0.05)的病例,术后疗效有显著差异.结论:MVD术后行MRTA检查,是预测术后疗效较为有效的方法之一,术后NVC分级越大和NVC缓解度越小的病例,MVD术后疼痛缓解不佳的可能性越高.     

Parasuicide: The value of suicidal intent and various motives as predictors of future suicidal behaviour

Abstract

The main aim of the study was to examine whether various aspects of suicidal intent or various motives for an index parasuicide can predict nonfatal or fatal repetition of suicidal behaviour. 776 parasuicide patients from 5 Nordic regions participating in the WHO/EURO Multicentre Study on Parasuicide were followed for one year. The Suicide Intent Scale (SIS) and the Motives for Parasuicide Questionnaire (MPQ) were used as predictor variables. A low level of suicidal intent predicted nonfatal repetition. The motive “make things easier for someone” differentiated female repeaters From male repeaters. The report of an unclear motive was the only significant predictor of fatal repetition. Suicidal intent and various motives for a parasuicide have some value in predicting repetition of suicidal behaviour. but should, perhaps. in future studies be combined with other variables in order to increase the predictive value.     

Experimental and Analytical Performance Evaluation of Short Circular Hydrodynamic Journal Bearings Used in Rotary Blood Pumps

Rotary blood pumps (RBPs) have demonstrated considerable promise while treating heart failure patients, such that they are being placed at an earlier stage of the disease. These devices may therefore be required to operate for prolonged durations which yields the need for RBPs exhibiting high durability, reliability, and blood compatibility. Noncontacting bearings, utilizing magnetic and/or hydrodynamic suspension techniques, appear to provide a suitable solution to these challenges. Hydrodynamic suspension has the advantage that it does not need feedback control systems. Among various hydrodynamic bearing types, the circular journal bearing has the particular benefit of easy manufacturing. This study presents methods to evaluate the performance of short (length to diameter ratio <1) circular hydrodynamic journal bearings (HJBs) for RBPs. Analytical calculations with specific boundary conditions are presented to predict the rotor's eccentricity under equilibrium states and thus the related performance parameters such as load capacity, power loss, and shear rates. These results and boundary conditions were confirmed experimentally in a specially designed test set‐up. The bearing performance was found to correlate to analytical solutions using the full Sommerfeld boundary condition instead of the half Sommerfeld condition conventionally used for such applications. Geometrical and operational parameter variations showed that HJB designs with a short Sommerfeld Number S_S >0.02 can provide sufficient fluid film thicknesses and low shear rates. The measurements were further used to evaluate the bearings' stability. The estimation of the stability threshold drawn in relation to a modified stability index and the equilibrium eccentricity of the rotor allows the prediction of stability for short circular HJB designs under full Sommerfeld condition.