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PloS One 2024Although sloped surfaces are common in daily living, most studies of body balance are carried out on flat surfaces, and few data are available for sloping angles below...
INTRODUCTION
Although sloped surfaces are common in daily living, most studies of body balance are carried out on flat surfaces, and few data are available for sloping angles below 14°.
OBJECTIVES
The purpose of this study was to explore the effect of forward and backward sloping surfaces at 7° and 15° on postural equilibrium and the activity of flexor/extensor ankle muscles.
METHODS
Fifteen healthy subjects (8 males and 7 females) (27.67 ± 3.9 years) underwent a posturographic examination associated with a surface electromyogram (EMG) of tibialis anterior (TA), soleus (Sol) and gastrocnemius medialis (GasM) under five conditions of support inclination: 0° (H0), backward inclination at 7° and 15° (DF7 and DF15), forward inclination at 7° and 15° (PF7 and PF15).
RESULTS
Results showed that the center of pressure (CP) was shifted according to the surface slope, with a forward move in PF7 (p <0.001) and PF15 (p <0.001) and a backward move in DF7 (p <0.01) and in DF15 (p <0.001). The mean displacement of the CP along the anterior-posterior axis (Xm) was increased in DF15 (p <0.01) relative to the H0 condition but reduced in PF7 (p <0.01). The normalized EMG revealed higher values when the muscles were in a shortened position (PF7 for Sol, p <0.05; PF15 for GasM, p <0.01; DF15 for TA, p<0.01) and lower values of GasM and Sol when lengthened (DF15, p <0.05).
CONCLUSION
Our findings indicate that standing on a backward sloped surface impairs body balance, while low-angle forward sloped surfaces might improve postural stability. Muscular activity variations of the ankle flexors/extensors, which are stretched or shortened, also seem to be related to the length-tension relationship of skeletal muscles.
Topics: Humans; Male; Female; Adult; Muscle, Skeletal; Postural Balance; Electromyography; Ankle; Young Adult; Ankle Joint
PubMed: 38935639
DOI: 10.1371/journal.pone.0305840 -
Sensors (Basel, Switzerland) Jun 2024The remote monitoring of vital signs via wearable devices holds significant potential for alleviating the strain on hospital resources and elder-care facilities. Among...
The remote monitoring of vital signs via wearable devices holds significant potential for alleviating the strain on hospital resources and elder-care facilities. Among the various techniques available, photoplethysmography stands out as particularly promising for assessing vital signs such as heart rate, respiratory rate, oxygen saturation, and blood pressure. Despite the efficacy of this method, many commercially available wearables, bearing Conformité Européenne marks and the approval of the Food and Drug Administration, are often integrated within proprietary, closed data ecosystems and are very expensive. In an effort to democratize access to affordable wearable devices, our research endeavored to develop an open-source photoplethysmographic sensor utilizing off-the-shelf hardware and open-source software components. The primary aim of this investigation was to ascertain whether the combination of off-the-shelf hardware components and open-source software yielded vital-sign measurements (specifically heart rate and respiratory rate) comparable to those obtained from more expensive, commercially endorsed medical devices. Conducted as a prospective, single-center study, the research involved the assessment of fifteen participants for three minutes in four distinct positions, supine, seated, standing, and walking in place. The sensor consisted of four PulseSensors measuring photoplethysmographic signals with green light in reflection mode. Subsequent signal processing utilized various open-source Python packages. The heart rate assessment involved the comparison of three distinct methodologies, while the respiratory rate analysis entailed the evaluation of fifteen different algorithmic combinations. For one-minute average heart rates' determination, the Neurokit process pipeline achieved the best results in a seated position with a Spearman's coefficient of 0.9 and a mean difference of 0.59 BPM. For the respiratory rate, the combined utilization of Neurokit and Charlton algorithms yielded the most favorable outcomes with a Spearman's coefficient of 0.82 and a mean difference of 1.90 BrPM. This research found that off-the-shelf components are able to produce comparable results for heart and respiratory rates to those of commercial and approved medical wearables.
Topics: Humans; Photoplethysmography; Respiratory Rate; Heart Rate; Software; Male; Signal Processing, Computer-Assisted; Female; Wearable Electronic Devices; Monitoring, Physiologic; Adult; Prospective Studies; Algorithms
PubMed: 38931550
DOI: 10.3390/s24123766 -
International Journal of Environmental... May 2024Children functioning at Gross Motor Function Classification System (GMFCS) levels IV-V cannot maintain an aligned standing position or take steps without support....
Children functioning at Gross Motor Function Classification System (GMFCS) levels IV-V cannot maintain an aligned standing position or take steps without support. Upright positioning and mobility devices have psycho-social significance for these children and their families, enhancing use of vision, communication, functioning and emotional well-being. Standers and supported stepping devices facilitate opportunities for biomechanical loading, potentially helping to build and maintain muscle and bone integrity, and they promote physical development. However, families are often required to choose between these two devices for their young child. This study aims to synthesize evidence for use and benefits of both supported standing and stepping devices through the lens of two contemporary theoretical frameworks to support clinical reasoning and implementation. The F-words for childhood development (functioning, family, fitness, fun, friends, future) and the interdependence-Human Activity Assistive Technology (iHAAT) models were combined to illustrate the complex interactions between the child, family, caregivers, peers and contextual factors when implementing standing and stepping devices with children at GMFCS levels IV and V. Supported standing and stepping devices provide complementary benefits, and both may be necessary starting at 9-15 months. We propose they both be included ON-Time, along with other age-appropriate positioning and mobility devices, to promote more equitable developmental opportunities for children with non-ambulant cerebral palsy.
Topics: Child; Child, Preschool; Humans; Cerebral Palsy; Self-Help Devices; Standing Position
PubMed: 38928915
DOI: 10.3390/ijerph21060669 -
Entropy (Basel, Switzerland) Jun 2024Self-organized criticality is a universal theory for dynamical systems that has recently been applied to the cardiovascular system. Precise methodological approaches are...
Self-organized criticality is a universal theory for dynamical systems that has recently been applied to the cardiovascular system. Precise methodological approaches are essential for understanding the dynamics of cardiovascular self-organized criticality. This study examines how the duration and quality of data recording affect the analysis of cardiovascular self-organized criticality, with a focus on the beat-by-beat heart rate variability time series obtained from seven healthy subjects in a standing position. Drawing a Zipf diagram, we evaluated the distribution of cardiovascular events of bradycardia and tachycardia. We identified tipping points for the distribution of both bradycardia and tachycardia events. By varying the recording durations (1, 2, 5, 10, 20, 30, and 40 min) and sampling frequencies (500, 250, and 100 Hz), we investigated their influence on the observed distributions. While shorter recordings can effectively capture cardiovascular events, they may underestimate the variables describing their distribution. Additionally, the tipping point of the Zipf distribution differs between bradycardia and tachycardia events. Comparisons of the distribution of bradycardia and tachycardia events should be conducted using long data recordings. Utilizing devices with lower sampling frequencies may compromise data fidelity. These insights contribute to refining experimental protocols and advancing our understanding of the complex dynamics underlying cardiovascular regulation.
PubMed: 38920505
DOI: 10.3390/e26060496 -
Frontiers in Nutrition 2024Assessment of fat mass has historically employed various methods like Dual-energy X-ray Absorptiometry (DXA), and bioelectrical impedance (BIA), and anthropometry with...
INTRODUCTION
Assessment of fat mass has historically employed various methods like Dual-energy X-ray Absorptiometry (DXA), and bioelectrical impedance (BIA), and anthropometry with its set of formulas. However, doubts persist regarding their validity and interchangeability to evaluate fat mass. This research aimed to determine the validity of anthropometry, and BIA in estimating fat mass Vs DXA, considering the influence of sex and hydration status.
METHODS
A descriptive, cross-sectional study included 265 young adults (161 males and 104 females), assessed through DXA, BIA in a standing position, and anthropometry. A fat mass estimation formula with DXA, a fat mass estimation formula with BIA and 10 fat mass estimation formulas with anthropometry were calculated.
RESULTS
Significant differences were found across DXA, BIA and anthropometry in both kilograms and percentages for the overall sample (<0.001), and when the covariable sex was included (p<0.001), with no significant effect of hydration status (=0.332-0.527). Bonferroni-adjusted analyses revealed significant differences from DXA with anthropometry and BIA in most cases for the overall sample (<0.001), as well as when stratified by sex (<0.001-0.016). Lin's coefficient indicated poor agreement between most of the formulas and methods both in percentage and kilograms of fat mass (CCC=0.135-0.892). In the Bland-Altman analysis, using the DXA fat mass values as a reference, lack of agreement was found in the general sample (<0.001-0.007), except for Carter's formula in kilograms (=0.136) and percentage (=0.929) and Forsyth for percentage (=0.365). When separating the sample by sex, lack of agreement was found in males for all methods when compared with both percentage and kilograms calculated by DXA (<0.001). In the female sample, all methods and formulas showed lack of agreement (<0.001-0.020), except for Evans's in percentage (=0.058).
CONCLUSION
The formulas for fat mass assessment with anthropometry and BIA may not be valid with respect to the values reported with DXA, with the exception of Carter's anthropometry formula for general sample and Evans's anthropometry formula for female sample. BIA could also be an alternative if what is needed is to assess fat mass in women as a group.
PubMed: 38919386
DOI: 10.3389/fnut.2024.1421950 -
Severe complex neglected infantile Blount disease acute correction by Ilizarov frame: A case report.International Journal of Surgery Case... Jun 2024Blount disease is a disorder causing three proportions of deformity, including varus deformity, procurvatum deformity, and internal tibial rotational deformity. The...
INTRODUCTION
Blount disease is a disorder causing three proportions of deformity, including varus deformity, procurvatum deformity, and internal tibial rotational deformity. The standardized treatment remains controversial despite extensive reviews. The application of Ilizarov external fixators for circumspect corrections is established. The SCARE 2023 criteria have been followed in reporting the case report.
CASE PRESENTATION
We present the case of a nine-year-old girl who's complaining about bowing on both of her knees. From the examination, we found that the metaphyseodiaphyseal angle of both knees was 50 degrees. On the right knee, there is 125 degrees of procurvatum deformity and 115 degrees of deformity on the left knee. After performing deformity correction with the Ilizarov application, there's clinical improvement in the patient.
CLINICAL DISCUSSION
Some experts advise using physeal distraction to manage the deformity in order to achieve correction. The limited popularity of physeal distraction technique may be attributed to the risks of premature closure of the growth plate that we manage to avoid. The Ilizarov frame provides maximum adjustability for aligning all planes, making it suitable for treating severe deformities. Secure fixation, improved patient mobility, being able to assess patient alignment in a functional standing position, and precision.
CONCLUSION
Acute correction and fixation using circular frames as a treatment option for Blount disease show positive outcomes without any significant complications.
PubMed: 38917699
DOI: 10.1016/j.ijscr.2024.109909 -
Philosophical Transactions. Series A,... Jul 2024Elucidating the role of strange baryons (hyperons) in neutron stars requires detailed knowledge of hyperon-nucleon interactions in the light (u,d,s) quark sector. The...
Elucidating the role of strange baryons (hyperons) in neutron stars requires detailed knowledge of hyperon-nucleon interactions in the light (u,d,s) quark sector. The structure of the hyperons and their excitation spectra also directly impact, and are an input to, models of big-bang nucleosynthesis. The upcoming K-long Facility will provide a much-needed intense and clean neutral strange meson beam, from which hyperons can be produced at rates where hyperon structure, hyperon-nucleon interactions and higher-order interactions can be studied with a new level of accuracy and for hitherto unreachable measurements. The new facility has the potential to address long-standing questions surrounding the strange sector of the strong force and its relevance to the structure of atomic nuclei, neutron stars and the cosmos at large. This article is part of the theme issue 'The liminal position of Nuclear Physics: from hadrons to neutron stars'.
PubMed: 38910456
DOI: 10.1098/rsta.2023.0124 -
Journal of Orthopaedic Surgery (Hong... 2024To observe the activation strategies of the ankle muscles using surface electromyography (sEMG) during single-leg standing (SLS) and both-leg standing (BLS) on flat...
To observe the activation strategies of the ankle muscles using surface electromyography (sEMG) during single-leg standing (SLS) and both-leg standing (BLS) on flat ground (FG), soft mat (SM), and BOSU ball (BB) surfaces. Thirty healthy young adults participated in the study. The muscle activities of the tibialis anterior (TA) and gastrocnemius medial (GM) were measured on the three surfaces during SLS and BLS. Electromyographic evaluations of the TA and GM were recorded during maximum voluntary isometric contractions (MVIC). Muscle activation was evaluated using MVIC%, and muscle co-contraction was evaluated using the co-contraction index (CI). A statistically significant increase was observed in the MVIC% of the TA, GM, and CI on the three surfaces during SLS compared to BLS, except for the comparison of CI on BB between SLS and BLS (t = -1.35, = 0.19). The MVIC% of the TA and GM during SLS and BLS on BB was significantly increased in comparison with FG and SM. The CI during BLS on BB increased compared to FG (t = 3.19, < 0.01) and SM (t = 4.64, < 0.01). The CI during BLS on SM (t = -1.46, = 0.15) decreased when compared to FG but without statistical significance. SLS and unstable surfaces can induce greater muscle activation, and SLS can have a greater influence on ankle muscles.
Topics: Humans; Electromyography; Male; Muscle, Skeletal; Young Adult; Female; Standing Position; Adult; Ankle Joint; Isometric Contraction; Ankle; Postural Balance
PubMed: 38910029
DOI: 10.1177/10225536241258336 -
BMJ Open Jun 2024The primary aim of this study was to investigate the feasibility and acceptability of general practitioners (GPs) using sit-stand desks to facilitate standing during...
OBJECTIVES
The primary aim of this study was to investigate the feasibility and acceptability of general practitioners (GPs) using sit-stand desks to facilitate standing during consultations. A further aim was to examine the views of patients about GPs standing for their consultations.
DESIGN
A pre-post single-group experimental trial design.
SETTING
General practices in England, UK.
PARTICIPANTS
42 GPs (working a minimum of five clinical sessions per week) and 301 patients (aged ≥18 years).
INTERVENTIONS
The intervention consisted of each GP having a sit-stand desk (Opløft Sit-Stand Platform) installed in their consultation room for 4 working weeks. Sit-stand desks allow users to switch, in a few seconds, between a sitting and standing position and vice versa, by adjusting the height of the desk.
MAIN OUTCOME MEASURES
To test feasibility and acceptability, GPs reported their views about using sit-stand desks at work at baseline and follow-up. Sitting time and physical activity were also measured via accelerometer at baseline and follow-up. Patients who attended a consultation where their GP was standing were asked to complete an exit questionnaire about the perceived impact on the consultation.
RESULTS
Most GPs reported using their sit-stand desk daily (n=28, 75.7%). 16 GPs (44.4%) used their sit-stand desk during face-to-face consultations every day. Most GPs and patients did not view that GPs standing during face-to-face consultations impacted the doctor-patient relationship (GPs; 73.5%, patients; 83.7%). GPs' sitting time during work was 121 min per day lower (95% CI: -165 to -77.58) at follow-up compared with baseline.
CONCLUSIONS
Use of sit-stand desks is acceptable within general practice and may reduce sitting time in GPs. This may benefit GPs and help reduce sitting time in patients.
TRIAL REGISTRATION NUMBER
ISRCTN76982860.
Topics: Humans; Feasibility Studies; Male; Female; Middle Aged; Adult; General Practitioners; Standing Position; Sitting Position; Attitude of Health Personnel; England; Surveys and Questionnaires; Exercise; General Practice; Aged; Interior Design and Furnishings
PubMed: 38910005
DOI: 10.1136/bmjopen-2024-084085 -
The Journal of Biological Chemistry Jun 2024Nonribosomal peptide synthetases (NRPSs) are responsible for the production of important biologically active peptides. The large, multidomain NRPSs operate through an...
Nonribosomal peptide synthetases (NRPSs) are responsible for the production of important biologically active peptides. The large, multidomain NRPSs operate through an assembly line strategy in which the growing peptide is tethered to carrier domains that deliver the intermediates to neighboring catalytic domains. While most NRPS domains catalyze standard chemistry of amino acid activation, peptide bond formation and product release, some canonical NRPS catalytic domains promote unexpected chemistry. The paradigm monobactam antibiotic sulfazecin is produced through the activity of a terminal thioesterase domain of SulM, which catalyzes an unusual β-lactam forming reaction in which the nitrogen of the C-terminal N-sulfo-2,3-diaminopropionate residue attacks its thioester tether to release the monobactam product. We have determined the structure of the thioesterase domain as both a free-standing domain and a didomain complex with the upstream holo peptidyl-carrier domain. The position of variant lid helices results in an active site pocket that is quite constrained, a feature that is likely necessary to orient the substrate properly for β-lactam formation. Modeling of a sulfazecin tripeptide into the active site identifies a plausible binding mode identifying potential interactions for the sulfamate and the peptide backbone with Arg2849 and Asn2819, respectively. The overall structure is similar to the β-lactone forming thioesterase domain that is responsible for similar ring closure in the production of obafluorin. We further use these insights to enable bioinformatic analysis to identify additional, uncharacterized β-lactam-forming biosynthetic gene clusters by genome mining.
PubMed: 38908753
DOI: 10.1016/j.jbc.2024.107489