A new portable 3-D gyroscope system for the evaluation of upper limb function

This study aims to develop a lightweight, portable and cost effective system for 3D motion analysis of the upper limb which can be readily applied within a clinical environment

Load distribution during sit-stand-sit using an instrumented chair

Paper examining the forces through the body during standing up and sitting down by means of force plates and transducers

Hand movement analysis of the elderly when using a remote control

The aim of the this project is to study the ability of older subjects to perform basic remote control manipulations and also to specify the minimal functional requirements to perform this activity of daily living

Knee kinematics of total knee replacement patients: pre and post operative analysis using computer generated images

This project aims to show a comparison of knee kinematics in pre- and post-operative knee replacement surgery, using computer animation to represent a patient specific model of the knee joint interactions under every day conditions

Protective ankle muscle activation strategies during quick turning movement in humans

Paper examining ankle muscle activation patterns and their role in protecting against sprain during quick turning movements

Optimal or antagonistic? muscle force solutions in the lower limb

Provides evidence of the appropriateness of different muscle force distribution protocols in a musculoskeletal model of the lower limb

A three-dimensional finite element model of maximal grip loading in the human wrist

The aim of this work was to create an anatomically accurate three-dimensional finite element model of the wrist, applying subject-specific loading and quantifying the internal load transfer through the joint during maximal grip. For three subjects, representing the anatomical variation at the wrist, loading on each digit was measured during a maximal grip strength test with simultaneous motion capture. The internal metacarpophalangeal joint load was calculated using a biomechanical model. High-resolution magnetic resonance scans were acquired to quantify bone geometry. Finite element analysis was performed, with ligaments and tendons added, to calculate the internal load distribution. It was found that for the maximal grip the thumb carried the highest load, an average of 72.2 ¡ 20.1 N in the neutral position. Results from the finite element model suggested that the highest regions of stress were located at the radial aspect of the carpus. Most of the load was transmitted through the radius, 87.5 per cent, as opposed to 12.5 per cent through the ulna with the wrist in a neutral position. A fully three-dimensional finite element analysis of the wrist using subject-specific anatomy and loading conditions was performed. The study emphasizes the importance of modelling a large ensemble of subjects in order to capture the spectrum of the load transfer through the wrist due to anatomical variation

Optical properties of the pseudogap state in underdoped cuprates

Recent optical measurements of deeply underdoped cuprates have revealed that a coherent Drude response persists well below the end of the superconducting dome. In addition, no large increase in optical effective mass has been observed, even at dopings as low as 1%. We show that this behavior is consistent with the resonating valence bond spin-liquid model proposed by Yang, Rice, and Zhang. In this model, the overall reduction in optical conductivity in the approach to the Mott insulating state is caused not by an increase in effective mass, but by a Gutzwiller factor, which describes decreased coherence due to correlations, and by a shrinking of the Fermi surface, which decreases the number of available charge carriers. We also show that in this model, the pseudogap does not modify the low-temperature, low-frequency behavior, though the magnitude of the conductivity is greatly reduced by the Gutzwiller factor. Similarly, the profile of the temperature dependence of the microwave conductivity is largely unchanged in shape, but the Gutzwiller factor is essential in understanding the observed difference in magnitude between ortho-I and -II YBa$_2$Cu$_3$O$_y$.Comment: 9 pages, 6 figures, submitted to Eur. Phys. J.

Respiratory muscle function in patients with nemaline myopathy

Publisher Copyright: © 2022 The AuthorsIn this cross-sectional study, we comprehensively assessed respiratory muscle function in various clinical forms of nemaline myopathy (NM) including non-volitional tests for diaphragm function. Forty-two patients with NM were included (10 males (25-74 y/o); 32 females (11-76 y/o)). The NM forms were typical (n=11), mild (n=7), or childhood-onset with slowness of movements (n=24). Forced vital capacity (FVC) and maximal inspiratory pressure were decreased in typical NM in comparison with childhood-onset NM with slowness (32.0 [29.0-58.5] vs 81.0 [75.0-87.0]%, p<0.01, and 35.0 [24.0-55.0] vs 81.0 [65.0-102.5] cmH2O, p<0.01). Eight patients with childhood-onset NM with slowness had respiratory muscle weakness. There was a low correlation between FVC and Motor Function Measure scores (r=0.48, p<0.01). End-inspiratory diaphragm thickness and twitch mouth pressure were decreased in patients requiring home mechanical ventilation compared to non-ventilated patients with normal lung function (1.8 [1.5-2.4] vs 3.1 [2.0-4.6] mm, p=0.049, and -7.9 [-10.9- -4.0] vs -14.9 [-17.3- -12.6], p=0.04). Our results show that respiratory muscle weakness is present in all NM forms, including childhood-onset NM with slowness, and may be present irrespective of the degree of general motor function impairment. These findings highlight the importance for screening of respiratory function in patients with NM to guide respiratory management.Peer reviewe

Diagnosis of community-acquired pneumonia in children : South African Thoracic Society guidelines (part 2)

BACKGROUND. Accurate diagnosis and attribution of the aetiology of pneumonia are important for measuring the burden of disease, implementing appropriate treatment strategies and developing more effective interventions. OBJECTIVES. To produce revised guidelines for the diagnosis of pneumonia in South African (SA) children, encompassing clinical, radiological and aetiological methods. METHODS. An expert group was established to review diagnostic evidence and make recommendations for a revised SA guideline. Published evidence was reviewed and graded using the British Thoracic Society grading system. RESULTS. Diagnosis of pneumonia should be considered in a child with acute cough, fast breathing or difficulty breathing. Revised World Health Organization guidelines classify such children into: (i) severe pneumonia; (ii) pneumonia (tachypoea or lower chest indrawing); or (iii) no pneumonia. Malnourished or immunocompromised children with lower chest indrawing should be managed as cases of severe pneumonia. Pulse oximetry should be done, with hospital referral for oxygen saturation <92%. A chest X-ray is indicated in severe pneumonia or when tuberculosis (TB) is suspected. Microbiological investigations are recommended in hospitalised patients or in outbreak settings. Improved aetiological methods show the importance of co-infections. Blood cultures have a low sensitivity (<5%), for diagnosing bacterial pneumonia. Highly sensitive, multiplex tests on upper respiratory samples or sputum detect multiple potential pathogens in most children. However, even in symptomatic children, it may be impossible to distinguish colonising from causative organisms, unless identification of the organism is strongly associated with attribution to causality, e.g. respiratory syncytial virus, Mycobacterium tuberculosis, Bordetella pertussis, influenza, para-influenza or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Investigations for TB should be considered in children with severe pneumonia who have been hospitalised, in a case of a known TB contact, if the tuberculin skin test is positive, if a child is malnourished or has lost weight, and in children living with HIV. Induced sputum may provide a higher yield than upper respiratory sampling for B. pertussis, M. tuberculosis and Pneumocystis jirovecii. CONCLUSIONS. Advances in clinical, radiological and aetiological methods have improved the diagnosis of childhood pneumonia.HJZ and SAM are supported by the South African Medical Research Council.The South African Medical Research Councilhttp://www.samj.org.zaam2021Paediatrics and Child Healt