RESUMO
BACKGROUND: Understanding of students' musculoskeletal health under home-schooling during the COVID-19 pandemic is limited. OBJECTIVES: (1) To investigate the prevalence and severity of musculoskeletal symptoms in home-schooled adolescents during the COVID-19 pandemic. (2) To evaluate the effect of an online exercise + ergonomics advice protocol on symptoms, compared with ergonomics advice alone. DESIGN: Cross-sectional symptom survey identifying eligible participants, followed by a pragmatic randomized controlled trial. SETTING: Online classes. PARTICIPANTS: Survey: 354 students (mean 16.6 years). TRIAL: 188 students with upper body musculoskeletal symptoms. INTERVENTIONS: Randomization to three groups (physical therapy exercises + ergonomics postural advice, ergonomics postural advice alone, nonintervention control) stratified by the site of symptoms (neck, shoulder, upper back). Interventions were orally delivered online (via WhatsApp) supplemented with written/illustrative material. Follow-up occurred at 8 weeks. OUTCOME MEASURES: Survey: prevalence of symptoms (Nordic Questionnaire). TRIAL: primary outcome = change in intensity of upper body symptoms (visual analogue scale); secondary outcome = number of participants reporting improvement in upper body symptoms. RESULTS: The 12-month prevalence of musculoskeletal disorders in the survey was 38% neck, 28% shoulder, and 35% upper back, with mean pain intensity of 3.6, 3.9, and 3.8, respectively, on 0-10 visual analogue scale: Two-thirds reported symptoms in multiple anatomical regions. In the trial, there was no statistically significant difference between the exercise + ergonomics group and ergonomics alone group on the primary outcome, yet both groups showed reduced symptom intensity compared with control (p < .001). More participants in the exercise + ergonomics group reported improvement than in the ergonomics advice alone group (p < .02). CONCLUSIONS: The prevalence of musculoskeletal symptoms was relatively high in home-schooled adolescents. Symptoms can be reduced by ergonomics advice with or without exercises, but the effect is enhanced by the addition of physical therapy exercises. The latter approach may be considered for improving schoolchildren's musculoskeletal health in the usual classroom setting.
RESUMO
The atomic force microscope (AFM), operating in contact mode, has been employed in buffer solution to study two proteins; (i) green fluorescent protein (GFP), from the hydromedusan jellyfish Aequorea victoria; and (ii) human oncostatin M (OSM), in the presence of size-selected gold nanoclusters pinned on to a highly oriented pyrolytic graphite substrate. The AFM images have revealed immobilization of single molecules of OSM, which are strongly bound to the gold nanoclusters. Conversely, no strong immobilization has been observed for the GFP, as these molecules were easily displaced by the scanning tip. The contrasting behaviour of the two proteins can be explained by the exposed molecular surface area of their cysteine residues as modelled on the basis of their respective X-ray crystallographic data structures. GFP contains two cysteine residues, but neither is readily available to chemisorb on the gold clusters, because the cysteines are largely inaccessible from the surface of the protein. In contrast, OSM has a total of five cysteine residues, with different degrees of accessibility, which make the protein amenable to anchoring on the nanoclusters. Statistical analysis of the height of the OSM molecules bound to the nanoclusters is in accordance with crystallographic data, and suggests various configurations of the proteins on the clusters, associated with the presence of different cysteine anchoring sites. These results suggest that the three-dimensional conformation of protein molecules is preserved when they are chemisorbed to size-selected gold clusters, thus opening a new route towards oriented immobilization of individual protein molecules.
