Does the score on the mrc strength scale reflect instrumented measures of maximal torque and muscle activity in post‐stroke survivors?

It remains unknown whether variation of scores on the Medical Research Council (MRC) scale for muscle strength is associated with operator‐independent techniques: dynamometry and surface electromyography (sEMG). This study aimed to evaluate whether the scores of the MRC strength scale are associated with instrumented measures of torque and muscle activity in post-stroke survivors with severe hemiparesis both before and after an intervention. Patients affected by a first ischemic or hemorrhagic stroke within 6 months before enrollment and with complete paresis were included in the study. The pre‐ and post‐treatment assessments included the MRC strength scale, sEMG, and dynamometry assessment of the triceps brachii (TB) and biceps brachii (BB) as measures of maximal elbow extension and flexion torque, respectively. Proprioceptive‐based training was used as a treatment model, which consisted of multidirectional exercises with verbal feedback. Each treatment session lasted 1 h/day, 5 days a week for a total 15 sessions. Nineteen individuals with stroke participated in the study. A significant correlation between outcome measures for the BB (MRC and sEMG p = 0.0177, ϱ = 0.601; MRC and torque p = 0.0001, ϱ = 0.867) and TB (MRC and sEMG p = 0.0026, ϱ = 0.717; MRC and torque p = 0.0001, ϱ = 0.873) were observed post intervention. Regression models revealed a relationship between the MRC score and sEMG and torque measures for both the TB and BB. The results confirmed that variation on the MRC strength scale is associated with variation in sEMG and torque measures, especially post intervention. The regression model showed a causal relationship between MRC scale scores, sEMG, and torque assessments

Permeability and conductivity of platelet-reinforced membranes and composites

We present large scale simulations of the diffusion constant $D$ of a random composite consisting of aligned platelets with aspect ratio $a/b>>1$ in a matrix (with diffusion constant $D_0$) and find that $D/D_0 = 1/(1+ c_1 x + c_2 x^2)$, where $x= a v_f/b$ and $v_f$ is the platelet volume fraction. We demonstrate that for large aspect ratio platelets the pair term ($x^2$) dominates suggesting large property enhancements for these materials. However a small amount of face-to-face ordering of the platelets markedly degrades the efficiency of platelet reinforcement.Comment: RevTeX, 5 pages, 4 figures, submitted to PR

Comparative study of the effect of long-term ageing on the behaviour of bitumen and mastics with mineral fillers

This paper is based on a part of the research project carried out at the request of the German Research Foundation (DFG), under research project No. WE 1642/1-2 and LE 3649/1-2 (FOR2089).This study aims to evaluate the effect of mineral fillers on bitumen ageing. Two different bitumens and four mastics were investigated in the unaged and long-term aged states, based on different properties (consistency, rheology, fatigue resistance and ductility). Mastics stiffened less due to ageing treatment than bitumens, especially with granite filler. However, the results of the performance tests were not definitive regarding the effect of the filler. Aged bitumen showed greater fatigue resistance and higher specific energy of ductile fracture than unaged bitumen, whereas the mastics showed minor variations in the specific energy of ductile fracture with ageing treatment, which is indicative of less ageing, but the fatigue resistance decreased significantly in mastics with one of the bitumens.authorsversionpublishe

Experience in the application of IEC/TR 61000-3-6 to harmonic allocation in transmission systems

Technical report IEC/TR 61000-3-6 is widely used as a guide to harmonic management in HV and MV networks, assisting in coordination of harmonic levels between utility and customer. In 2001, Australia and New Zealand adopted the harmonic standard AS/NZS 61000.3.6, which closely follows the above IEC technical report. As a result, transmission utilities and connected loads are required by government regulations to abide by the harmonic allocations set by the standard. The technical report contains some useful general principles which can be applied to the harmonic management of power systems. However, unexpected difficulties can be found when attempts are made to apply them to large power systems. The formal procedure recommended by the standard for calculation of harmonic emission levels limits the voltage at the point of connection. There can be situations where the highest harmonic voltages are remote from the PCC. This can be accounted for by taking into account interactions between each injecting load and all other busbars in one single step. This leads to the development of a harmonic allocation constant , which will apply to the entire transmission network, as a measure of the ability of the network to absorb harmonics without violating a set planning limit. At present, the allocation procedure given in the standard implies consideration of only a single network operation scenario. However, substantial variations have been identified in the harmonic behaviour of transmission networks, including harmonic absorption capacity, with changes in generator commitment and switching configuration. The proposed approach accounts for variations by taking data from multiple network scenarios. For the specification of an easily-measurable harmonic current emission level - rather than a harmonic voltage level - for a particular customer, the network harmonic impedance is necessary. This quantity can vary substantially at the one busbar in a transmission network. The application of a standardised hth harmonic impedance is proposed which is based on the fundamental frequency fault level at the PCC. IEC/TR 61000-3-6 gives no guidance as to methods of treating harmonic resonances in transmission systems. Resonances will occur in any transmission system with sufficient line lengths, and will impose substantial constraints on harmonic allocation if computer calculations are accepted without modification. It is unclear if these resonances are of practical importance, and it is proposed that resonance amplifications be limited to allow useful allocations until their importance has been established by field results

Bostonia: 1998-1999, no. 1, 3-4

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Development and validation of two clinical prediction models to inform clinical decision-making for lumbar spinal fusion surgery for degenerative disorders and rehabilitation following surgery: protocol for a prospective observational study

INTRODUCTION: Potential predictors of poor outcome will be measured at baseline: (1) preoperatively to develop a clinical prediction model to predict which patients are likely to have favourable outcome following lumbar spinal fusion surgery (LSFS) and (2) postoperatively to predict which patients are likely to have favourable long-term outcomes (to inform rehabilitation). METHODS AND ANALYSIS: Prospective observational study with a defined episode inception of the point of surgery. Electronic data will be collected through the British Spine Registry and will include patient-reported outcome measures (eg, Fear-Avoidance Beliefs Questionnaire) and data items (eg, smoking status). Consecutive patients (≥18 years) undergoing LSFS for back and/or leg pain of degenerative cause will be recruited. EXCLUSION CRITERIA: LSFS for spinal fracture, inflammatory disease, malignancy, infection, deformity and revision surgery. 1000 participants will be recruited (n=600 prediction model development, n=400 internal validation derived model; planning 10 events per candidate prognostic factor). The outcome being predicted is an individual's absolute risk of poor outcome (disability and pain) at 6 weeks (objective 1) and 12 months postsurgery (objective 2). Disability and pain will be measured using the Oswestry Disability Index (ODI), and severity of pain in the previous week with a Numerical Rating Scale (NRS 0-10), respectively. Good outcome is defined as a change of 1.7 on the NRS for pain, and a change of 14.3 on the ODI. Both linear and logistic (to dichotomise outcome into low and high risk) multivariable regression models will be fitted and mean differences or ORs for each candidate predictive factor reported. Internal validation of the derived model will use a further set of British Spine Registry data. External validation will be geographical using two spinal registries in The Netherlands and Switzerland. ETHICS AND DISSEMINATION: Ethical approval (University of Birmingham ERN_17-0446A). Dissemination through peer-reviewed journals and conferences

Measures of central sensitization and their measurement properties in musculoskeletal trauma: A systematic review

Background and Objective: Chronic pain following musculoskeletal trauma is common, which may partially be attributed to the early presence of central sensitization (CS). Multiple measures are suggested to assess clinical features of CS, yet no systematic review has evaluated the measurement properties of these measures in a musculoskeletal trauma population. Databases and Data Treatment: This systematic review, which followed a published and PROSPERO registered protocol (CRD42018091531), aimed to establish the scope of CS measures used within a musculoskeletal trauma population and evaluate their measurement properties. Searches were conducted in two stages by two independent reviewers. The Consensus-based Standards for the selection of Health Measurement Instruments (COSMIN) checklist was used to evaluate risk of bias and overall quality was assessed using the modified Grading of Recommendations Assessment, Development and Evaluation. Results: From 86 studies, 30 different CS outcome measures were identified. Nine studies evaluated measurement properties of nine outcome measures; eight evaluated reliability and one evaluated construct validity. Measures included seven quantitative sensory testing methods (pressure, cold and electrical pain thresholds; warm, cold and vibration detection thresholds; vibration perception thresholds), pain drawings and a pinwheel. Risk of bias was assessed as doubtful/inadequate for all but one study, overall quality of evidence was low/very low for all measures. Reliability of measures ranged from poor to excellent. Conclusions: Many measures are used to evaluate CS but with limited established measurement properties in musculoskeletal trauma. High quality research to establish measurement properties of CS outcome measures is required

How does Low Back Pain Influence Muscle Activity during a Cyclical Dynamic Lifting Task?

Title How does LBP Influence Muscle Activity during a Cyclical Dynamic Lifting Task? Authors Andy Sanderson, Corrado Cescon, Nicola R. Heneghan, Alison Rushton, Marco Barbero, Pauline Kuithan, Deborah Falla Purpose Chronic non-specific low back pain (cLBP) is a leading cause of disability, limiting activity in 540 million people globally. High-density electromyography (HDEMG) has been used to investigate changes in back muscle activity in people with cLBP. Previous studies have utilised static or mono-planar tasks or focussed on small areas of the erector spinae (ES). This study uses innovative HDEMG and kinematic analysis to investigate the effect of cLBP on muscle activity and movement during a multi-planar lifting task. Methods Sixteen people with cLBP (8 male, age: 26.9±10.8 years) and sixteen age and gender-matched controls (7 male, age: 31.7±14.0 years) completed the study. HDEMG signals from the ES were detected with four 64-channel semi-disposable 13x5 electrode grids (2 grids bilaterally) covering the lumbar and thoraco-lumbar ES. Kinematic surface markers were placed over the back, enabling 3D motion capture. HDEMG and kinematic data were recorded continuously during a dynamic task involving the cyclical lifting of a 5kg box between 6 shelves for 10 cycles (~7 minutes). The shelves were arranged around the participant, at knee and sternal height, with one pair of shelves anterior and two pairs lateral. To the beat of a metronome, the participant moved the box between shelves, returning to a central shelf each time (10 movements). HDEMG amplitude data were normalised to the first cycle for each movement to a shelf, and factorial ANOVA’s used to compare subsequent cycles to the first. Results Kinematic analysis revealed no significant differences between groups in the movement pattern used to complete the lifting task (P>0.05 for all relevant outcomes). Despite similar movements, significant differences in muscle activity, were seen between groups. The cLBP group showed systematically higher amplitude, indicating higher levels of muscle activity, in 6/10 shelf movements (P0.05). Conclusion As the data were normalised and amplitude is a measure of muscle activity, these results indicate that for a majority of movements, the activity in the ES for the LBP group did not show as great a reduction over the task as that of the control group. These data therefore support an altered motor control strategy in participants with cLBP. While no differences were found in the movement strategy, likely due to the standardisation of the task, cLBP participants showed lower reductions in activity, indicating that already fatigued or dysfunctional muscles remained in use throughout the task

Ecological conflicts and valuation - mangroves vs. shrimp in the late 1990s

Shrimps are produced in two different ways. They are fished in the sea (sometimes at the cost of turtle destruction) or they are "farmed" in ponds in coastal areas. Such aquaculture is increasing around the world as shrimps become a valuable item of world trade. Mangrove forests are sacrificed for commercial shrimp farming. This paper considers the conflict between mangrove conservation and shrimp exports in different countries.Who has title to the mangroves, who wins and who loses in this tragedy of enclosures? Which languages of valuation are used by different actors in order to compare the increase in shrimp exports and the losses in livelihoods and in environmental services? The economic valuation of damages is only one of the possible languages of valuation which are relevant in practice. Who has the power to impose a particular language of valuation