CROSS RECURRENCE QUANTIFICATION ANALYSIS OF INTER-LEG RELATIONS ACROSS THE GAIT TRANSITION

The aim of this study was to quantify characteristics of the deterministic properties of inter-leg movements over the gait transition. The purpose was to further understanding of the nonlinear characteristics of the gait of a healthy individual. A participant locomoted on a treadmill as the speed steadily increased from 0 to 18 km/h over a 120 s period. Position of the approximate center of rotation of the bilateral toe, ankle, knee and hip, were collected (CODAmotion; 100 Hz). The mathematical addition of the four markers representing the “free leg” in the direction of travel (x direction) provided the variables “left leg” and “right leg”. Each leg was embedded with a dimension of 3 and time lag of 18 points to create the Taken’s vector. Cross Recurrent Quantification Analysis (RQA) was then performed. Two distinct phases in the combined dynamics of the leg-leg system were observed, with lower determinism in the walking phase compared to running, separated by a clear, sharp transition. Results indicate that determinism in the cross dynamics of the two legs seems to play a role similar to an order parameter for the walk-run phase transition. This work increases our understanding of the nonlinear dynamics characteristics of the gait transition

Let us do better: learning lessons for recovery of healthcare professionals during and after COVID-19

The COVID-19 pandemic emphasises the need to rethink and restructure the culture of healthcare organisations if we are to ensure the long-term well-being and mental health of healthcare provider organisations and their staff. In this paper, we recognise the high levels of stress and distress among staff of healthcare services before the COVID-19 pandemic began. We identify lessons for care of healthcare staff and illustrate the paths by which support mobilises and later deteriorates. Although this paper focuses on NHS staff in the UK, we contend that similar effects are likely in most healthcare systems

INFLUENCE OF CALCULATION PARAMETERS ON NONLINEAR DYNAMICS MEASURES

Nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent biomechanics studies. The aim of this study is to identify the range of time delay and embedding dimension values estimated for gait data, and how sensitive Lyapunov exponent and correlation dimension are to the range of these values. A participant walked at 3 km/h and ran at 9 km/h on a treadmill for 2 minutes. Lyaponuv exponent and correlation dimension were calculated based on a combination of the optimal and mean average time delay (TD) and embedding dimension (ED) for both angle and marker data. In the majority of literature, only one ED and TD is considered for LyE estimation, based on an average across data or values suggested in previous papers. However, the results of our study show that every angle or position, has an optimum ED and TD, and the use of these values affects the nonlinear dynamics values in non-trivial ways

Lifetime mental disorders and suicidal behaviour in South Africa

Background: There is relatively little data on the relationship between lifetime mental disorders and suicidal behaviour in low and middle income countries. This study examines the relationship between lifetime mental disorders, and subsequent suicide ideation, plans, and suicide attempts in South Africa. Method: A national survey of 4185 South African adults was conducted using the World Health Organization Composite International Diagnostic Interview (CIDI) to generate psychiatric diagnoses and suicidal behaviour. Bivariate, multivariate and discrete-time survival analyses were employed to investigate the associations between mental disorders and subsequent suicide ideation, plans, and attempts. Results: Sixty-one percent of people who seriously considered killing themselves at some point in their lifetime reported having a prior DSM-IV disorder. Mental disorders predict the onset of suicidal ideation, but have weaker effects in predicting suicide plans or attempts. After controlling for comorbid mental disorders, PTSD was the strongest predictor of suicidal ideation and attempts. There is a relationship between number of mental disorders and suicidal behaviour, with comorbidity having significantly sub-additive effects. Conclusion: Consistent with data from the developed world, mental disorders are strong predictors of suicidal behaviour, and these associations are more often explained by the prediction of ideation, rather than the prediction of attempts amongst ideators. This suggests some universality of the relevant mechanisms underlying the genesis of suicidal thoughts, and the progression to suicide attempts.Key Words: Suicide; Survey; South Africa; Mental Disorders

The use of conservation biomass feedstocks as potential bioenergy resources in the United Kingdom

A number of countries have introduced energy policies to reduce the emission of carbon dioxide which, in the case of bio-heat, has resulted in increased use of small wood burning stoves and boilers, particularly in Europe. There are issues surrounding the supply of sustainable wood feedstock, prompting a desire to utilise local biomass resources. This includes biomass generated through the management of natural woodlands in nature reserves and conservation areas. These management practices can also extend to other areas, such as raised bog wildernesses and estuary Reed beds. We term the biomass from this resource as conservation biomass. This study is concerned with the viability of this resource as a fuel within the United Kingdom, and combustion tests were carried out using a small domestic stove. It was concluded that there is as much as 500 kt y−1 that could be used in this way

Effectiveness of moving on: an Australian designed generic self-management program for people with a chronic illness

Background: This paper presents the evaluation of “Moving On”, a generic self-management program for people with a chronic illness developed by Arthritis NSW. The program aims to help participants identify their need for behavior change and acquire the knowledge and skills to implement changes that promote their health and quality of life. Method: A prospective pragmatic randomised controlled trial involving two group programs in community settings: the intervention program (Moving On) and a control program (light physical activity). Participants were recruited by primary health care providers across the north-west region of metropolitan Sydney, Australia between June 2009 and October 2010. Patient outcomes were self-reported via pre- and post-program surveys completed at the time of enrolment and sixteen weeks after program commencement. Primary outcomes were change in self-efficacy (Self-efficacy for Managing Chronic Disease 6-Item Scale), self-management knowledge and behaviour and perceived health status (Self-Rated Health Scale and the Health Distress Scale). Results: A total of 388 patient referrals were received, of whom 250 (64.4%) enrolled in the study. Three patients withdrew prior to allocation. 25 block randomisations were performed by a statistician external to the research team: 123 patients were allocated to the intervention program and 124 were allocated to the control program. 97 (78.9%) of the intervention participants commenced their program. The overall attrition rate of 40.5% included withdrawals from the study and both programs. 24.4% of participants withdrew from the intervention program but not the study and 22.6% withdrew from the control program but not the study. A total of 62 patients completed the intervention program and follow-up evaluation survey and 77 patients completed the control program and follow- up evaluation survey. At 16 weeks follow-up there was no significant difference between intervention and control groups in self-efficacy; however, there was an increase in self-efficacy from baseline to follow-up for the intervention participants (t=−1.948, p=0.028). There were no significant differences in self-rated health or health distress scores between groups at follow-up, with both groups reporting a significant decrease in health distress scores. There was no significant difference between or within groups in self-management knowledge and stage of change of behaviours at follow-up. Intervention group attenders had significantly higher physical activity (t=−4.053, p=0.000) and nutrition scores (t=2.315, p= 0.01) at follow-up; however, these did not remain significant after adjustment for covariates. At follow-up, significantly more participants in the control group (20.8%) indicated that they did not have a self-management plan compared to those in the intervention group (8.8%) (X2=4.671, p=0.031). There were no significant changes in other self-management knowledge areas and behaviours after adjusting for covariates at follow-up. Conclusions: The study produced mixed findings. Differences between groups as allocated were diluted by the high proportion of patients not completing the program. Further monitoring and evaluation are needed of the impact and cost effectiveness of the program. Trial registration: Australian New Zealand Clinical Trials Registry: ACTRN1260900029821

MicroRNA regulation of the paired-box transcription factor Pax3 confers robustness to developmental timing of myogenesis

Commitment of progenitors in the dermomyotome to myoblast fate is the first step in establishing the body musculature. Pax3 is a crucial transcription factor, important for skeletal muscle development and expressed in myogenic progenitors in the dermomyotome of developing somites and in migratory muscle progenitors that populate the limb buds. Down-regulation of Pax3 is essential to ignite the myogenic program, including up-regulation of myogenic regulators, Myf-5 and MyoD. MicroRNAs (miRNAs) confer robustness to developmental timing by posttranscriptional repression of genetic programs that are related to previous developmental stages or to alternative cell fates. Here we demonstrate that the muscle-specific miRNAs miR-1 and miR-206 directly target Pax3. Antagomir-mediated inhibition of miR-1/miR-206 led to delayed myogenic differentiation in developing somites, as shown by transient loss of myogenin expression. This correlated with increased Pax3 and was phenocopied using Pax3-specific target protectors. Loss of myogenin after antagomir injection was rescued by Pax3 knockdown using a splice morpholino, suggesting that miR-1/miR-206 control somite myogenesis primarily through interactions with Pax3. Our studies reveal an important role for miR-1/miR-206 in providing precision to the timing of somite myogenesis. We propose that posttranscriptional control of Pax3 downstream of miR-1/miR-206 is required to stabilize myoblast commitment and subsequent differentiation. Given that mutually exclusive expression of miRNAs and their targets is a prevailing theme in development, our findings suggest that miRNA may provide a general mechanism for the unequivocal commitment underlying stem cell differentiation

Efficient Mixing at low Reynolds numbers using polymer additives

Mixing in fluids is a rapidly developing field of fluid mechanics \cite{Sreen,Shr,War}, being an important industrial and environmental problem. The mixing of liquids at low Reynolds numbers is usually quite weak in simple flows, and it requires special devices to be efficient. Recently, the problem of mixing was solved analytically for a simple case of random flow, known as the Batchelor regime \cite{Bat,Kraich,Fal,Sig,Fouxon}. Here we demonstrate experimentally that very viscous liquids at low Reynolds number, $Re$. Here we show that very viscous liquids containing a small amount of high molecular weight polymers can be mixed quite efficiently at very low Reynolds numbers, for a simple flow in a curved channel. A polymer concentration of only 0.001% suffices. The presence of the polymers leads to an elastic instability \cite{LMS} and to irregular flow \cite{Ours}, with velocity spectra corresponding to the Batchelor regime \cite{Bat,Kraich,Fal,Sig,Fouxon}. Our detailed observations of the mixing in this regime enable us to confirm sevearl important theoretical predictions: the probability distributions of the concentration exhibit exponential tails \cite{Fal,Fouxon}, moments of the distribution decay exponentially along the flow \cite{Fouxon}, and the spatial correlation function of concentration decays logarithmically.Comment: 11 pages, 5 figure

Biopolymer-Based Nanohydroxyapatite Composites for the Removal of Fluoride, Lead, Cadmium, and Arsenic from Water

In this study, hydroxyapatite (HAP) nanocomposites were prepared with chitosan (HAP-CTS), carboxymethyl cellulose (HAP-CMC), alginate (HAP-ALG), and gelatin (HAP-GEL) using a simple wet chemical in situ precipitation method. The synthesized materials were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, and thermogravimetric analysis. This revealed the successful synthesis of composites with varied morphologies. The adsorption abilities of the materials toward Pb(II), Cd(II), F–, and As(V) were explored, and HAP-CTS was found to have versatile adsorption properties for all of the ions, across a wide range of concentrations and pH values, and in the presence of common ions found in groundwater. Additionally, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy confirmed the affinity of HAP-CTS toward multi-ion mixture containing all four ions. HAP-CTS was hence engineered into a more user-friendly form, which can be used to form filters through its combination with cotton and granular activated carbon. A gravity filtration study indicates that the powder form of HAP-CTS is the best sorbent, with the highest breakthrough capacity of 3000, 3000, 2600, and 2000 mL/g for Pb(II), Cd(II), As(V), and F–, respectively. Hence, we propose that HAP-CTS could be a versatile sorbent material for use in water purification