ENERGETICS OF LOWER EXTREMITY MOVEMENTS PREDICTED USING AN EMG-DRIVEN MUSCLE MODEL

An EMG-driven muscle model is described and applied to the analysis of a loaded squat movement, vertical jumping performance, and walking, jogging and running gait. The main findings are: (i) for the up phase of the loaded squat the monoarticular hip and knee extensors account for approximately 80% of the work done by the muscle tendon complexes; (ii) differences in movement amplitude of the whole body centre of gravity between the countermovement jump and the squat jump may be explained by differences in muscle-tendon dynamics; and (iii) the amount of mechanical energy transferred between joints via biarticular muscles during the support phase of gait increases as a function of gait speed

Triceps Surae Short Latency Stretch Reflexes Contribute to Ankle Stiffness Regulation during Human Running

During human running, short latency stretch reflexes (SLRs) are elicited in the triceps surae muscles, but the function of these responses is still a matter of controversy. As the SLR is primarily mediated by Ia afferent nerve fibres, various methods have been used to examine SLR function by selectively blocking the Ia pathway in seated, standing and walking paradigms, but stretch reflex function has not been examined in detail during running. The purpose of this study was to examine triceps surae SLR function at different running speeds using Achilles tendon vibration to modify SLR size. Ten healthy participants ran on an instrumented treadmill at speeds between 7 and 15 km/h under 2 Achilles tendon vibration conditions: no vibration and 90 Hz vibration. Surface EMG from the triceps surae and tibialis anterior muscles, and 3D lower limb kinematics and ground reaction forces were simultaneously collected. In response to vibration, the SLR was depressed in the triceps surae muscles at all speeds. This coincided with short-lasting yielding at the ankle joint at speeds between 7 and 12 km/h, suggesting that the SLR contributes to muscle stiffness regulation by minimising ankle yielding during the early contact phase of running. Furthermore, at the fastest speed of 15 km/h, the SLR was still depressed by vibration in all muscles but yielding was no longer evident. This finding suggests that the SLR has greater functional importance at slow to intermediate running speeds than at faster speeds

The effectiveness and cost-effectiveness of mindfulness-based cognitive therapy compared with maintenance antidepressant treatment in the prevention of depressive relapse/recurrence: results of a randomised controlled trial (the PREVENT study)

Background: Individuals with a history of recurrent depression have a high risk of repeated depressive relapse/recurrence. Maintenance antidepressant medication (m-ADM) for at least 2 years is the current recommended treatment, but many individuals are interested in alternatives to m-ADM. Mindfulness-based cognitive therapy (MBCT) has been shown to reduce the risk of relapse/recurrence compared with usual care but has not yet been compared with m-ADM in a definitive trial. Objectives: To establish whether MBCT with support to taper and/or discontinue antidepressant medication (MBCT-TS) is superior to and more cost-effective than an approach of m-ADM in a primary care setting for patients with a history of recurrent depression followed up over a 2-year period in terms of preventing depressive relapse/recurrence. Secondary aims examined MBCT’s acceptability and mechanism of action. Design: Single-blind, parallel, individual randomised controlled trial. Setting: UK general practices. Participants: Adult patients with a diagnosis of recurrent depression and who were taking m-ADM. Interventions: Participants were randomised to MBCT-TS or m-ADM with stratification by centre and symptomatic status. Outcome data were collected blind to treatment allocation and the primary analysis was based on the principle of intention to treat. Process studies using quantitative and qualitative methods examined MBCT’s acceptability and mechanism of action. Main outcomes measures: The primary outcome measure was time to relapse/recurrence of depression. At each follow-up the following secondary outcomes were recorded: number of depression-free days, residual depressive symptoms, quality of life, health-related quality of life and psychiatric and medical comorbidities. Results: In total, 212 patients were randomised to MBCT-TS and 212 to m-ADM. The primary analysis did not find any evidence that MBCT-TS was superior to m-ADM in terms of the primary outcome of time to depressive relapse/recurrence over 24 months [hazard ratio (HR) 0.89, 95% confidence interval (CI) 0.67 to 1.18] or for any of the secondary outcomes. Cost-effectiveness analysis did not support the hypothesis that MBCT-TS is more cost-effective than m-ADM in terms of either relapse/recurrence or quality-adjusted life-years. In planned subgroup analyses, a significant interaction was found between treatment group and reported childhood abuse (HR 1.89, 95% CI 1.06 to 3.38), with delayed time to relapse/recurrence for MBCT-TS participants with a more abusive childhood compared with those with a less abusive history. Although changes in mindfulness were specific to MBCT (and not m-ADM), they did not predict outcome in terms of relapse/recurrence at 24 months. In terms of acceptability, the qualitative analyses suggest that many people have views about (dis)/continuing their ADM, which can serve as a facilitator or a barrier to taking part in a trial that requires either continuation for 2 years or discontinuation. Conclusions: There is no support for the hypothesis that MBCT-TS is superior to m-ADM in preventing depressive relapse/recurrence among individuals at risk for depressive relapse/recurrence. Both treatments appear to confer protection against relapse/recurrence. There is an indication that MBCT may be most indicated for individuals at greatest risk of relapse/recurrence. It is important to characterise those most at risk and carefully establish if and why MBCT may be most indicated for this group

Non-invasive visualisation and identification of fluorescent Leishmania tarentolae in infected sand flies

Background: The leishmaniases are neglected diseases that affect some of the most vulnerable populations in the tropical and sub-tropical world. The parasites are transmitted by sand flies and novel strategies to control this neglected vector-borne disease are needed. Blocking transmission by targeting the parasite inside the phlebotomine vector offers potential in this regard. Some experimental approaches can be best performed by longitudinal study of parasites within flies, for which non-destructive methods to identify infected flies and to follow parasite population changes are required. Methods:Lutzomyia longipalpis were reared under standard insectary conditions at the Wellcome Centre for Molecular Parasitology. Flies were artificially infected with L. tarentolae expressing green fluorescent protein (GFP. Parasite counts were carried out 5 days post-infection and the percentage of infected flies and survival of infected females was established up to days 5 post-infection. Whole living females were visualised using an epifluorescence inverted microscope to detect the presence parasites inferred by a localised green fluorescent region in the upper thorax. Confirmation of infection was performed by localised-fluorescence of dissected flies and estimates of the parasite population. Results:Leishmania tarentolae was successfully transfected and expressed GFP in vitro. L. tarentolae-GFP Infected flies showed similar parasite populations when compared to non-transfected parasites ( L. tarentolae-WT). Survival of non-infected females was higher than L. tarentolae-infected groups, (Log-rank (Mantel-Cox) test, p<0.05). L. tarentolae-GFP infected females displayed an intense localised fluorescence in the thorax while other specimens from the same infected group did not. Localised fluorescent flies were dissected and showed higher parasite populations compared to those that did not demonstrate high concentrations in this region (t-test, p<0.005). Conclusion: These results demonstrate the feasibility of establishing a safe non-human infectious fluorescent Leishmania-sand fly infection model by allowing non-destructive imaging to signal the establishment of Leishmania infections in living sand flies

The validity, responsiveness, and score interpretation of the PROMISnq Physical Function – Multiple Sclerosis 15a short form in multiple sclerosis

© 2022 Published by Elsevier B.V.Background A valid, sensitive patient-reported outcome (PRO) measure of physical function (PF) for people with multiple sclerosis (MS) would have substantial value in routine care and clinical research. We now describe development of the PROMISnq Short Form v2.0 PF – Multiple Sclerosis 15a [PROMISnq PF(MS)15a] for assessing PF in relapsing and progressive MS. Also, the validity, reliability, and responsiveness of the PROMISnq PF(MS)15a is evaluated, minimal important difference (MID) thresholds for score change estimated and a score interpretation guide developed. Methods A mixed-methods sequential design was employed. Relevant PF concepts were elicited through semi-structured interviews with people with relapsing MS, and then mapped to the PROMIS PF item bank. Measurement experts integrated results from interviews with people with MS and input from a panel of neurologists to generate a draft short form. Relevance and comprehensiveness of the draft short form were assessed in cognitive debriefing interviews with people with relapsing or progressive MS. Subsequently, item reduction and evaluation of psychometric properties were performed in two observational studies: a cross-sectional study in the US (n = 296), and a 96-week longitudinal study in the UK MS Register cohort (n = 558). The main outcomes and measures are estimates of: known-groups validity, convergent validity, reliability, responsiveness; MID for worsening. Results Factor analyses supported the unidimensionality of the newly derived 15-item short form. Cronbach's alpha (≥ 0.97) and intraclass correlation coefficient (≥ 0.97) of test-retest scores (5–27 days) indicated strong reliability. Convergent validity was demonstrated by moderate-to-strong correlations with scores on related PRO measures. Scores discriminated among patient groups classified by levels of physical health and other criteria. Score changes of 2.3–2.7 points are proposed as MID criteria for minimal worsening in PF. Conclusion PROMISnq PF(MS)15a demonstrated reliability, validity and sensitivity to change. Input from patients and clinicians ensured the content is comprehensive and relevant for people with MS.Peer reviewe

Mechanisms of Adaptation from a Multiple to a Single Step Recovery Strategy following Repeated Exposure to Forward Loss of Balance in Older Adults

When released from an initial, static, forward lean angle and instructed to recover with a single step, some older adults are able to meet the task requirements, whereas others either stumble or fall. The purpose of the present study was to use the concept of margin of stability (MoS) to investigate balance recovery responses in the anterior-posterior direction exhibited by older single steppers, multiple steppers and those that are able to adapt from multiple to single steps following exposure to repeated forward loss of balance. One hundred and fifty-one healthy, community dwelling, older adults, aged 65–80 years, participated in the study. Participants performed four trials of the balance recovery task from each of three initial lean angles. Balance recovery responses in the anterior-posterior direction were quantified at three events; cable release (CR), toe-off (TO) and foot contact (FC), for trials performed at the intermediate lean angle. MoS was computed as the anterior-posterior distance between the forward boundary of the Base of Support (BoS) and the vertical projection of the velocity adjusted centre of mass position (XCoM). Approximately one-third of participants adapted from a multiple to a single step recovery strategy following repeated exposure to the task. MoS at FC for the single and multiple step trials in the adaptation group were intermediate between the exclusively single step group and the exclusively multiple step group, with the single step trials having a significant, 3.7 times higher MoS at FC than the multiple step trials. Consistent with differences between single and multiple steppers, adaptation from multiple to single steps was attributed to an increased BoS at FC, a reduced XCoM at FC and an increased rate of BoS displacement from TO to FC. Adaptations occurred within a single test session and suggest older adults that are close to the threshold of successful recovery can rapidly improve dynamic stability following repeated exposure to a forward loss of balance

Third order dielectric susceptibility in a model quantum paraelectric

In the context of perovskite quantum paraelectrics, we study the effects of a quadrupolar interaction $J_q$, in addition to the standard dipolar one $J_d$. We concentrate here on the nonlinear dielectric response $\chi_{P}^{(3)}$, as the main response function sensitive to quadrupolar (in our case antiquadrupolar) interactions. We employ a 3D quantum four-state lattice model and mean-field theory. The results show that inclusion of quadrupolar coupling of moderate strength ($J_q \sim {{1}\over{4}} J_d$) is clearly accompanied by a double change of sign of $\chi_{P}^{(3)}$ from negative to positive, near the quantum temperature $T_Q$ where the quantum paraelectric behaviour sets in. We fit our $\chi_{P}^{(3)}$ to recent experimental data for SrTiO$_3$, where the sign change is identified close to $T_Q \sim 37 K$.Comment: 22 page

Glastir Monitoring & Evaluation Programme. First year annual report

The Welsh Government has commissioned a comprehensive new ecosystem monitoring and evaluation programme to monitor the effects of Glastir, its new land management scheme, and to monitor progress towards a range of international biodiversity and environmental targets. A random sample of 1 km squares stratified by landcover types will be used both to monitor change at a national level in the wider countryside and to provide a backdrop against which intervention measures are assessed using a second sample of 1 km squares located in areas eligible for enhanced payments for advanced interventions. Modelling in the first year has forecast change based on current understanding, whilst a rolling national monitoring programme based on an ecosystem approach will provide an evidence-base for on-going, adaptive development of the scheme by Welsh Government. To our knowledge, this will constitute the largest and most in-depth ecosystem monitoring and evaluation programme of any member state of the European Union

A written self-help intervention for depressed adults comparing behavioural activation combined with physical activity promotion with a self-help intervention based upon behavioural activation alone: study protocol for a parallel group pilot randomised controlled trial (BAcPAc)

notes: PMCID: PMC4061537types: Journal Article© 2014 Farrand et al.; licensee BioMed Central Ltd.Challenges remain to find ways to support patients with depression who have low levels of physical activity (PA) to overcome perceived barriers and enhance the perceived value of PA for preventing future relapse. There is an evidence-base for behavioural activation (BA) for depression, which focuses on supporting patients to restore activities that have been avoided, but practitioners have no specific training in promoting PA. We aimed to design and evaluate an integrated BA and PA (BAcPAc) practitioner-led, written, self-help intervention to enhance both physical and mental health.NPRI-