109 research outputs found
Changes in infant segment inertias during the first three months of independent walking
BACKGROUND: During infancy, rapid changes in physical growth affect the size and shape of the body segments. To understand the effects of growth on movement, it is first necessary to quantify rates of development during the acquisition of important motor milestones. The goal of this longitudinal study was to quantify the physical growth of infant body segments during the initial stages of independent walking. METHODS: Ten infants (N = 10) aged between 28 and 55 weeks at the beginning of the study were tested biweekly (every two weeks) for three months. A 13-segment mathematical model of the human body was used to estimate the inertial parameters of the infant body segments at each session. An analysis of variance was used to test for significant differences in segment masses between biweekly measures. Polynomial contrasts were used to test for linear trends in the growth data. RESULTS: Significant differences between biweekly measures of segment mass were found only for the head/neck (F(5,45) = 3.42, p < 0.05), upper trunk (F(5,45) = 4.04, p < 0.01), and lower trunk (F(5,45) = 3.49, p < 0.01). The lower trunk demonstrated a linear increase in mass (F(1,9) = 4.56, p < 0.05). However, the upper trunk demonstrated a quadratic trend in growth (F(1,9) = 9.13, p < 0.01), while the head/neck segment showed a cubic trend in growth (F(1,9) = 3.80, p < 0.05). Significant differences in axial segment masses were also found between subjects (F(9,45) = 5.92, p < 0.001). CONCLUSION: Given that postural control proceeds in a cephalocaudal manner, the lower trunk segment would be brought under control last, in terms of the axial segments. Increases in the mass of this segment could constrain the system, thereby acting as a control parameter for the onset and development of motor patterns
Identifying Planetary Biosignature Impostors: Spectral Features of CO and O4 Resulting from Abiotic O2/O3 Production
O2 and O3 have been long considered the most robust individual biosignature
gases in a planetary atmosphere, yet multiple mechanisms that may produce them
in the absence of life have been described. However, these abiotic planetary
mechanisms modify the environment in potentially identifiable ways. Here we
briefly discuss two of the most detectable spectral discriminants for abiotic
O2/O3: CO and O4. We produce the first explicit self-consistent simulations of
these spectral discriminants as they may be seen by JWST. If JWST-NIRISS and/or
NIRSpec observe CO (2.35, 4.6 um) in conjunction with CO2 (1.6, 2.0, 4.3 um) in
the transmission spectrum of a terrestrial planet it could indicate robust CO2
photolysis and suggest that a future detection of O2 or O3 might not be
biogenic. Strong O4 bands seen in transmission at 1.06 and 1.27 um could be
diagnostic of a post-runaway O2-dominated atmosphere from massive H-escape. We
find that for these false positive scenarios, CO at 2.35 um, CO2 at 2.0 and 4.3
um, and O4 at 1.27 um are all stronger features in transmission than O2/O3 and
could be detected with SNRs 3 for an Earth-size planet orbiting a
nearby M dwarf star with as few as 10 transits, assuming photon-limited noise.
O4 bands could also be sought in UV/VIS/NIR reflected light (at 0.345, 0.36,
0.38, 0.445, 0.475, 0.53, 0.57, 0.63, 1.06, and 1.27 um) by a next generation
direct-imaging telescope such as LUVOIR/HDST or HabEx and would indicate an
oxygen atmosphere too massive to be biologically produced.Comment: 7 pages, 4 figures, accepted to the Astrophysical Journal Letter
Functional electrical stimulation cycling exercise after spinal cord injury: a systematic review of health and fitness-related outcomes.
ObjectivesThe objective of this review was to summarize and appraise evidence on functional electrical stimulation (FES) cycling exercise after spinal cord injury (SCI), in order to inform the development of evidence-based clinical practice guidelines.MethodsPubMed, the Cochrane Central Register of Controlled Trials, EMBASE, SPORTDiscus, and CINAHL were searched up to April 2021 to identify FES cycling exercise intervention studies including adults with SCI. In order to capture the widest array of evidence available, any outcome measure employed in such studies was considered eligible. Two independent reviewers conducted study eligibility screening, data extraction, and quality appraisal using Cochranes' Risk of Bias or Downs and Black tools. Each study was designated as a Level 1, 2, 3 or 4 study, dependent on study design and quality appraisal scores. The certainty of the evidence for each outcome was assessed using GRADE ratings ('High', 'Moderate', 'Low', or 'Very low').ResultsNinety-two studies met the eligibility criteria, comprising 999 adults with SCI representing all age, sex, time since injury, lesion level and lesion completeness strata. For muscle health (e.g., muscle mass, fiber type composition), significant improvements were found in 3 out of 4 Level 1-2 studies, and 27 out of 32 Level 3-4 studies (GRADE rating: 'High'). Although lacking Level 1-2 studies, significant improvements were also found in nearly all of 35 Level 3-4 studies on power output and aerobic fitness (e.g., peak power and oxygen uptake during an FES cycling test) (GRADE ratings: 'Low').ConclusionCurrent evidence indicates that FES cycling exercise improves lower-body muscle health of adults with SCI, and may increase power output and aerobic fitness. The evidence summarized and appraised in this review can inform the development of the first international, evidence-based clinical practice guidelines for the use of FES cycling exercise in clinical and community settings of adults with SCI. Registration review protocol: CRD42018108940 (PROSPERO)
Correlação entre lipidose hepática, variação da condição corporal e analitos hepáticos em bovinos leiteiros
Liver lipidosis is a metabolic disorder mostly observed in high yielding dairy cattle, especially during the transition period. The aim of this study was to determine the correlation between hepatic lipid infiltration, biochemical indicators of liver function, and body condition score (BCS) variation in dairy cows. Fifty-one multiparous Holstein cows raised in a confined system were evaluated. Liver biopsies and blood samples were collected, and BCS was measured on days 3 and 28 postpartum. Lipid infiltration was determined by histologic examination. The plasma activity of aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyl transferase and concentration of beta-hydroxybutyrate, non-esterified fatty acids, albumin, total bilirubin, and cholesterol were determined. BCS was measured using objective (camera) and subjective (visual) methods. Mild lipid infiltration was found in 3.92% of cows sampled on day 3 and 5.88% on day 28. Bilirubin was significantly higher on day 3 than on day 28 postpartum, and cholesterol was significantly higher on day 28 than on day 3 in all cows. There was no difference in biochemical analytes between cows with and without lipidosis. On day 3, mean subjective BCS was 3.10 and objective BCS was 3.16, while on day 28, these scores were 2.91 and 2.99, respectively. The calculated liver function index (LFI) was found to be a more sensitive indicator of liver function than the hepatic analytes evaluated. No correlation between BCS variation and lipid infiltration was found. Cholesterol and bilirubin levels showed the most remarkable changes during the early postpartum period. LFI is a potential indicator of postpartum liver function.A lipidose hepática é um distúrbio metabólico principalmente observado nos bovinos de leite de alto rendimento, especialmente no período de transição. O objetivo deste estudo foi determinar a correlação entre infiltração lipídica hepática, indicadores bioquímicos de função hepática e variação da condição corporal em bovinos leiteiros. Foram avaliadas cinquenta e um vacas multíparas de raça Holandesa em confinamento. Coletaram-se biopsias de fígado e amostras de sangue, e a condição corporal (BCS) aferiu-se nos dias 3 e 28 pós-parto. A infiltração lipídica determinou-se mediante avaliação histológica. Mensuraram-se a atividade da aspartato aminotransferase, fosfatase alcalina e da gama-glutamil transferase, concentração de beta-hidroxibutirato, ácidos graxos não esterificados, albumina, bilirrubina total e colesterol. A BCS mediu-se utilizando método objetivo (câmera) e subjetivo (visualmente). Observou-se discreta infiltração lipídica em 3,92% dos bovinos amostrados no dia 3 e 5,88% no dia 28. Em todos os bovinos a bilirrubina foi significativamente mais alta no dia 3 do que no dia 28 e o colesterol foi superior no dia 28 do que no dia 3. Não houve diferença nos analitos bioquímicos dos bovinos com e sem lipidose. No dia 3, a média subjetiva da BCS foi 3,10 e a objetiva 3,16, enquanto no dia 28, obtiveram-se valores de 2,91, e 2,99 respectivamente. O índice calculado de função hepática mostrou ser um indicador mais sensível da função hepática do que os analitos avaliados individualmente. Não houve correlação entre a variação do BCS e infiltração lipídica
Getting Recovery Right After Neck Dissection (GRRAND-F): mixed-methods feasibility study to design a pragmatic randomised controlled trial
Introduction We will evaluate the feasibility of a randomised controlled trial to estimate the effectiveness and cost-effectiveness of a rehabilitation intervention on pain, function and health-related quality of life following neck dissection (ND) after head and neck cancer (HNC). Methods and analysis This is a pragmatic, multicentred, feasibility study. Participants are randomised to usual care (control) or usual care plus an individualised, rehabilitation programme (Getting Recovery Right After Neck Dissection, GRRAND intervention). Adults aged over 18 with HNC for whom ND is part of their care will be recruited from specialist clinics. Participants are randomised in 1:1 ratio using a web-based service. The target sample size is 60 participants. Usual care will be received by all participants during their postoperative inpatient stay consisting standard National Health Service care supplemented with a booklet advising on postoperative self-management strategies. The GRRAND intervention programme consists of usual care plus up to six individual physiotherapy sessions including neck and shoulder range of motion (ROM) and progressive resistance exercises, advice and education. Between sessions participants will be advised to complete a home exercise programme. The primary outcome is to determine recruitment and retention rates from study participants across sites. Outcomes will be measured at 6 and 12 months. Participants and physiotherapists will be invited to an optional qualitative interview at the completion of their involvement in the study. The target qualitative sample size is 15 participants and 12 physiotherapists. Interviews aim to further investigate the feasibility and acceptability of the intervention and to determine wider experiences of the study design and intervention from patient and physiotherapist perspectives. Ethics and dissemination Ethical approval was given on 29 October 2019 (National Research Ethics Committee Number: 19/SC/0457). Results will be reported at conferences and in peer-reviewed publications. Trial registration number ISRCTN11979997. Status Trial recruitment is ongoing and is expected to be completed by 30 August 2021
Using Three-Dimensional Gait Data for Foot/Ankle Orthopaedic Surgery
We present the case of a forty year old male who sustained a torn carotid during strenuous physical activity. This was followed by a right hemispheric stroke due to a clot associated with the carotid. Upon recovery, the patient’s gait was characterized as hemiparetic with a stiff-knee pattern, a fixed flexion deformity of the toe flexors, and a hindfoot varus. Based on clinical exams and radiographs, the surgical treatment plan was established and consisted of correction of the forefoot deformities, possible hamstrings lengthening, and tendon transfer of the posterior tibial tendon to the dorsolateral foot. To aid in surgical planning, a three-dimensional gait analysis was conducted using a state-of-the-art motion capture system. Data from this analysis provided insight into the pathomechanics of the patient’s gait pattern. A forefoot driven hindfoot varus was evident from the presurgical data and the tendon transfer procedure was deemed unnecessary. A computer was used in the OR to provide surgeons with animations of the patient’s gait and graphical results as needed. A second gait analysis was conducted 6 weeks post surgery, shortly after cast removal. Post-surgical gait data showed improved foot segment orientation and position. Motion capture data provides clinicians with detailed information on the multisegment kinematics of foot motion during gait, before and during surgery. Further, treatment effectiveness can be evaluated by repeating gait analyses after recovery
Comparison of two normative paediatric gait databases
The availability of age-matched normative data is an essential component of clinical gait analyses. Comparison of normative gait databases is difficult due to the high-dimensionality and temporal nature of the various gait waveforms. The purpose of this study was to provide a method of comparing the sagittal joint angle data between two normative databases. We compared a modern gait database to the historical San Diego database using statistical classifiers developed by Tingley et al. (2002). Gait data were recorded from 60 children aged 1–13 years. A six-camera Vicon 512 motion analysis system and two force plates were utilized to obtain temporal-spatial, kinematic, and kinetic parameters during walking. Differences between the two normative data sets were explored using the classifier index scores, and the mean and covariance structure of the joint angle data from each lab. Significant differences in sagittal angle data between the two databases were identified and attributed to technological advances and data processing techniques (data smoothing, sampling, and joint angle approximations). This work provides a simple method of database comparison using trainable statistical classifiers
Androgen receptor signaling regulates follicular growth and steroidogenesis in interaction with gonadotropins in the ovary during mini-puberty in mice
In females, androgens contribute to ovarian diseases such as polycystic ovarian syndrome (PCOS), but their action is also crucial for ovarian physiology, i.e., follicular growth and estradiol (E2) synthesis during reproductive life, in interaction with the gonadotropins LH and FSH. However, it is unclear whether androgens already play a role in the ovary at mini-puberty, a phase of postnatal development with active follicular growth and high E2 levels. Therefore, we analyzed the potential actions of androgens on the ovary and their possible interaction with gonadotropins during this period in mice. We used molecular-based studies and pharmacological approaches in vivo and on cultured ovaries. We found that mini-pubertal ovaries produce significant amounts of testosterone and display androgen receptor (AR) expression in growing follicles, both under the control of LH. By blocking AR signaling either in vivo or in ovarian cultures, we found that this pathway may participate in the regulation of prepubertal E2 synthesis and follicular growth, possibly by regulating the expression of a number of key intra-ovarian regulators, including FSH receptor (Fshr), the aromatase enzyme converting androgens into estrogens (Cyp19a1) and the cell cycle inhibitor p27KIP1 (Cdkn1b). We further showed that AR may stimulate FSH-mediated regulation of Cyp19a1 through its action on Fshr mRNA abundance. Overall, this work supports the idea that AR signaling is already activated in mini-pubertal ovaries to regulate E2 synthesis and follicular growth, at the interplay with LH and FSH signaling. Its early action may, thus, contribute to the implementation of early ovarian function with possible impacts on reproductive function
Getting Recovery Right After Neck Dissection (GRRAND-F): mixed-methods feasibility study to design a pragmatic randomised controlled trial
Objective: To determine the feasibility of a randomised controlled trial to estimate the effectiveness and cost-effectiveness of a rehabilitation intervention following neck dissection (ND) after head and neck cancer (HNC). Design: Two-arm, open, pragmatic, parallel, multicentre, randomised controlled feasibility trial. Setting: Two UK NHS hospitals. Participants: People who had HNC in whom a ND was part of their care. We excluded those with a life expectancy of six months or less, pre-existing, long-term neurological disease affecting the shoulder and cognitive impairment. Intervention: Usual care (standard care supplemented with a booklet on postoperative self-management) was received by all participants. The GRRAND intervention programme consisted of usual care plus up to six individual physiotherapy sessions including neck and shoulder range of motion and progressive resistance exercises, advice and education. Between sessions, participants were advised to complete a home exercise programme. Randomisation: 1:1 randomisation. Allocation was based on minimisation, stratified by hospital site and spinal accessory nerve sacrifice. It was not possible to mask treatment received. Main outcome measures: Primary: Participant recruitment, retention and fidelity to the study protocol and interventions from study participants and staff at six months post-randomisation (and 12 months for those reaching that time-point). Secondary: clinical measures of pain, function, physical performance, health-related quality of life, health utilisation and adverse events. Results: 36 participants were recruited and enrolled. The study achieved five of its six feasibility targets. These included consent - 70% of eligible participants were consented; intervention fidelity - 78% participants discharged completed the intervention sessions; contamination - none - no participants in the control arm received the GRRAND-F intervention and retention - 8% of participants were lost to follow-up. The only feasibility target that was not achieved was the recruitment target where only 36 of the planned 50 participants were recruited over 18 months. This was principally due to the COVID-19 pandemic which caused all research activity to be paused or reduced, with a subsequent reduction in. Conclusions: Based on the findings a full-trial can now be designed to better understand whether this proposed intervention is effective
- …