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1.
Scand J Med Sci Sports ; 34(5): e14636, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38671551

RESUMO

Hypertension is a leading risk factor for cardiovascular disease and is modulated by genetic variants. This study aimed to assess the effect of obesity genetic liability and physical activity on hypertension among European and African ancestry individuals within the UK Biobank (UKB). Participants were 230 115 individuals of European ancestry and 3239 individuals of African ancestry from UKB. Genetic liability for obesity were estimated using previously published data including genetic variants and effect sizes for body mass index (BMI), waist-hip ratio (WHR) and waist circumference (WC) using Plink software. The outcome was defined as stage 2 hypertension (systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥90 mmHg, or the use of anti-hypertensive medications). The association between obesity genetic liability and the outcome was assessed across categories of self-reported physical activity using logistic regression. Among European ancestry participants, there was up to a 1.2 greater odds of hypertension in individuals with high genetic liability and low physical activity compared to individuals with low genetic liability and high physical activity (p < 0.001). In individuals engaging in low levels of physical activity compared with moderate/high physical activity, the effect of BMI genetic liability on hypertension was greater (p interaction = 0.04). There was no evidence of an association between obesity genetic liability and hypertension in individuals of African ancestry in the whole sample or within separate physical activity groups (p > 0.05). This study suggests that higher physical activity levels are associated with lower odds of stage 2 hypertension among European ancestry individuals who carry high genetic liability for obesity. This cannot be inferred for individuals of African ancestry, possibly due to the low African ancestry sample size within the UKB.


Assuntos
Adiposidade , População Negra , Exercício Físico , Hipertensão , Obesidade , População Branca , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adiposidade/genética , População Negra/genética , Pressão Sanguínea/genética , Índice de Massa Corporal , Predisposição Genética para Doença , Hipertensão/genética , Obesidade/genética , Fatores de Risco , Reino Unido , Circunferência da Cintura , Relação Cintura-Quadril , População Branca/genética , África/etnologia , Europa (Continente)/etnologia
2.
Eur J Appl Physiol ; 124(4): 1163-1174, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37950762

RESUMO

PURPOSE: This study examined the acute effects of interrupting sitting with light-intensity walking on postprandial cardiometabolic risk markers in South Asian adults. METHODS: South Asians with overweight/obesity (n = 19; body mass index [BMI] > 23 kg·m-2) and normal-weight (n = 8; BMI 18.0-22.9 kg·m-2) aged 48.8 ± 5.6 years completed two, 5-h conditions: (1) prolonged sitting (SIT), and (2) interrupted sitting with 5-min bouts of light-intensity walking every 30-min (INT-SIT). Blood samples and resting expired air samples were collected throughout each condition. Statistical analyses were completed using linear mixed models. RESULTS: In participants with overweight/obesity, postprandial glucose, triglycerides (TAG) and metabolic load index (MLI) over time were lower, whereas resting substrate utilisation and resting energy expenditure (REE) were higher, in INT-SIT than SIT (all p ≤ 0.05). Compared with SIT (0.18 [95% CI 0.13, 0.22] kcal.min-1), INT-SIT (0.23 [95% CI 0.18, 0.27] kcal.min-1) increased postprandial REE iAUC in participants with overweight/obesity (p = 0.04, d = 0.51). Postprandial TAG concentrations over time were lower in INT-SIT versus SIT (p = 0.01, d = 30) in normal-weight participants, with no differences in any other outcomes for this sample group. CONCLUSION: These findings suggest that interrupting sitting with 5-min bouts of light walking every 30-min acutely attenuates cardiometabolic risk markers among South Asians living with overweight/obesity, whereas limited effects may be seen in individuals with normal-weight.


Assuntos
Doenças Cardiovasculares , Sobrepeso , Adulto , Humanos , Glicemia/metabolismo , Insulina , Estudos Cross-Over , Obesidade/metabolismo , Caminhada , Período Pós-Prandial
3.
Br J Sports Med ; 58(2): 73-80, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-37945324

RESUMO

OBJECTIVES: This study aimed to (1) develop a new measure of adherence to exercise for musculoskeletal (MSK) pain (Adherence To Exercise for Musculoskeletal Pain Tool: ATEMPT) based on previously conceptualised domains of exercise adherence, (2) report the content and structural validity, internal consistency, test-retest reliability, and measurement error for the ATEMPT outcome measure in patients managed with exercise for MSK pain. METHODS: ATEMPT was created using statements describing adherence generated by patients, physiotherapists and researchers, with content validity established. Baseline and retest questionnaires were distributed to patients recommended exercise for MSK pain in 11 National Health Service physiotherapy clinics. Items demonstrating low response variation were removed and the following measurement properties assessed: structural validity, internal consistency, test-retest reliability and measurement error. RESULTS: Baseline and retest data were collected from 382 and 112 patients with MSK pain, respectively. Confirmatory factor analysis established that a single factor solution was the best fit according to Bayesian Information Criterion. The 6-item version of the measure (scored 6-30) demonstrated optimal internal consistency (Cronbach's Alpha 0.86, 95% CI 0.83 to 0.88) with acceptable levels of test-retest reliability (intraclass correlation coefficient 0.84, 95% CI 0.78 to 0.88) and measurement error (smallest detectable change 3.77, 95% CI 3.27 to 4.42) (SE of measurement 2.67, 95% CI 2.31 to 3.16). CONCLUSION: The 6-item ATEMPT was developed from the six domains of exercise adherence. It has adequate content and structural validity, internal consistency, test-retest reliability and measurement error in patients with MSK pain, but should undergo additional testing to establish the construct validity and responsiveness.


Assuntos
Dor Musculoesquelética , Humanos , Reprodutibilidade dos Testes , Teorema de Bayes , Medicina Estatal , Psicometria , Inquéritos e Questionários
4.
Appetite ; 182: 106445, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36592798

RESUMO

The aim of this study was to determine the appetite-related responses to breaking up prolonged sitting with physical activity bouts differing in frequency and duration among adult females. Fourteen sedentary females aged 34 ± 13 years with a body mass index of 27.1 ± 6.3 kg/m2 (mean ± SD) took part in a randomised crossover trial with three, 7.5 h conditions: (1) uninterrupted sitting (SIT), (2) sitting with short frequent 2-min moderate-intensity walking breaks every 30 min (SHORT-BREAKS), and (3) sitting with longer duration, less frequent 10-min moderate-intensity walking breaks every 170-180 min (LONG-BREAKS). The intensity and total duration of physical activity was matched between the SHORT-BREAKS and LONG-BREAKS conditions. Linear mixed models were used to compare the outcomes between conditions with significance being accepted as p ≤ 0.05. There were no significant between-condition differences in hunger, satisfaction, prospective food consumption or overall appetite area under the curve (AUC) (all p ≥ 0.801). Absolute ad libitum energy intake and relative energy intake (REI) did not differ significantly between conditions (all p ≥ 0.420). Acylated ghrelin and total peptide YY incremental and total AUC did not differ significantly between conditions (all p ≥ 0.388). Yet, there was a medium effect size for the higher acylated ghrelin incremental AUC in SHORT-BREAKS versus SIT (d = 0.61); the reverse was seen for total AUC, which was lower in SHORT-BREAKS versus SIT (d = 0.69). These findings suggest that breaking up sitting does not lead to compensatory changes in appetite, appetite hormones or energy intake regardless of physical activity bout duration and frequency among adult females.


Assuntos
Apetite , Ingestão de Energia , Exercício Físico , Adulto , Feminino , Humanos , Estudos Cross-Over , Grelina , Caminhada/fisiologia , Adulto Jovem , Pessoa de Meia-Idade , Postura Sentada , Comportamento Sedentário
5.
J Synchrotron Radiat ; 29(Pt 1): 89-102, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34985426

RESUMO

Portland cement based grouts used for radioactive waste immobilization contain high replacement levels of supplementary cementitious materials, including blast-furnace slag and fly ash. The minerals formed upon hydration of these cements may have capacity for binding actinide elements present in radioactive waste. In this work, the minerals ettringite (Ca6Al2(SO4)3(OH)12·26H2O) and hydrotalcite (Mg6Al2(OH)16CO3·4H2O) were selected to investigate the importance of minor cement hydrate phases in sequestering and immobilizing UVI from radioactive waste streams. U LIII-edge X-ray absorption spectroscopy (XAS) was used to probe the UVI coordination environment in contact with these minerals. For the first time, solid-state 27Al magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy was applied to probe the Al coordination environment in these UVI-contacted minerals and make inferences on the UVI coordination, in conjunction with the X-ray spectroscopy analyses. The U LIII-edge XAS analysis of the UVI-contacted ettringite phases found them to be similar (>∼70%) to the uranyl oxyhydroxides present in a mixed becquerelite/metaschoepite mineral. Fitting of the EXAFS region, in combination with 27Al NMR analysis, indicated that a disordered Ca- or Al-bearing UVI secondary phase also formed. For the UVI-contacted hydrotalcite phases, the XAS and 27Al NMR data were interpreted as being similar to uranyl carbonate, that was likely Mg-containing.

6.
J Transl Med ; 20(1): 370, 2022 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-35974414

RESUMO

BACKGROUND: The IO Score is a 27-gene immuno-oncology (IO) classifier that has previously predicted benefit to immune checkpoint inhibitor (ICI) therapy in triple negative breast cancer (TNBC) and non-small cell lung cancer (NSCLC). It generates both a continuous score and a binary result using a defined threshold that is conserved between breast and lung. Herein, we aimed to evaluate the IO Score's binary threshold in ICI-naïve TCGA bladder cancer patients (TCGA-BLCA) and assess its clinical utility in metastatic urothelial cancer (mUC) using the IMvigor210 clinical trial treated with the ICI, atezolizumab. METHODS: We identified a list of tumor immune microenvironment (TIME) related genes expressed across the TCGA breast, lung squamous and lung adenocarcinoma cohorts (TCGA-BRCA, TCGA-LUSQ, and TCGA-LUAD, 939 genes total) and then examined the expression of these 939 genes in TCGA-BLCA, to identify patients as having high inflammatory gene expression. Using this as a test of classification, we assessed the previously established threshold of IO Score. We then evaluated the IO Score with this threshold in the IMvigor210 cohort for its association with overall survival (OS). RESULTS: In TCGA-BLCA, IO Score positive patients had a strong concordance with high inflammatory gene expression (p < 0.0001). Given this concordance, we applied the IO Score to the ICI treated IMvigor210 patients. IO Score positive patients (40%) had a significant Cox proportional hazard ratio (HR) of 0.59 (95% CI 0.45-0.78 p < 0.001) for OS and improved median OS (15.6 versus 7.5 months) compared to IO Score negative patients. The IO Score remained significant in bivariate models combined with all other clinical factors and biomarkers, including PD-L1 protein expression and tumor mutational burden. CONCLUSION: The IMvigor210 results demonstrate the potential for the IO Score as a clinically useful biomarker in mUC. As this is the third tumor type assessed using the same algorithm and threshold, the IO Score may be a promising candidate as a tissue agnostic marker of ICI clinical benefit. The concordance between IO Score and inflammatory gene expression suggests that the classifier is capturing common features of the TIME across cancer types.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Antígeno B7-H1/genética , Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Ensaios Clínicos como Assunto , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias Pulmonares/patologia , Microambiente Tumoral
7.
Age Ageing ; 51(11)2022 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-36436008

RESUMO

Acrodermatitis enteropathica (AE) is a rare disorder which can be congenital or acquired. The main features are peri-orificial dermatitis, gastrointestinal symptom in the form of diarrhoea, acral dermatitis and alopecia, among others. This report aims to highlight that AE is an important differential diagnosis to consider, when managing older patients with mucosal infections or ulcerations. Here, we present the case of a 68-year-old female with end-stage liver disease who presented with a right inter-trochanteric femoral fracture following a fall and was noted, on admission, to have non-healing mucosal ulcers.


Assuntos
Acrodermatite , Úlcera , Feminino , Humanos , Idoso , Úlcera/diagnóstico , Úlcera/etiologia , Acrodermatite/diagnóstico , Acrodermatite/etiologia , Zinco , Vulva
8.
BMC Public Health ; 22(1): 458, 2022 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-35255850

RESUMO

OBJECTIVE: Sedentary workplace interventions have had success in reducing excessive sitting time in office workers, but barriers to implementation and uptake remain. This study formally assessed a theory-derived, sit-stand desk intervention using the APEASE (Acceptability, Practicability, Effectiveness, Affordability, Side-effects, Equity) criteria. METHODS: Thirteen adults (eight female, mean age 38 ± 10 years) from the treatment arm of a sedentary behaviour intervention participated in semi-structured interviews. Thematic codes were inductively assigned to data items followed by deductive charting using the APEASE criteria. RESULTS: The intervention was highly acceptable, practicable, safe to deploy, and helped workers reduce workplace sitting time, though individual preferences and workload mediated engagement. Affordability of sit-stand desks and Equity of access were potential barriers to uptake. CONCLUSIONS: Through the lens of the APEASE criteria, this theory-derived, multi-component sit-stand desk intervention showed acceptability, practicability and effectiveness in reducing and breaking up sedentary time at work with minimal side effects. Using this approach with further tailoring and personalisation may help workers achieve greater reductions in workplace sitting, though affordability and equity should be considered further.


Assuntos
Saúde Ocupacional , Local de Trabalho , Adulto , Custos e Análise de Custo , Feminino , Humanos , Pessoa de Meia-Idade , Comportamento Sedentário , Carga de Trabalho
9.
Educ Inf Technol (Dordr) ; 27(8): 10497-10516, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35464111

RESUMO

Second language (L2) writing strategies are essential for successful learning outcomes in courses with a substantial writing component and this is especially true during emergency remote teaching (ERT) when online writing tasks help compensate for the missing offline communication. Online writing tasks are multimodal and interactive, and widely delivered through assignment modules, discussion forums, social media, and other online channels, yet little is known pertaining to L2 writing strategies and online writing beliefs. The current study investigates the types of L2 writing strategies students employed during ERT in the midst of Covid-19 and then used structural modeling to understand how strategies relate to online writing task perceptions, L2 writing anxiety, and L2 writing proficiency. The four L2 writing strategy categories are related to planning, monitoring, reviewing, and translating. Following a cross-sectional survey design, a total of 256 South Korean EFL students completed the study's questionnaire administered during their second semester of ERT. Overall, students reported using planning and monitoring strategies the most while using moderate levels of translation and review strategies. Translation strategies produced a significant positive relationship with L2 writing anxiety, indicating effort-avoidance behavior among apprehensive writers. Contrarily, planning and review strategies were positively associated with increased levels of perceived benefits with online writing tasks. When added to the model, the statistically significant correlations among monitoring category and outcome variables vanished, indicating a mediation effect. Along with addressing future directions in L2 writing strategy research in the post-Covid era, some pedagogical implications for the evolving application of translation strategies are discussed.

10.
Educ Inf Technol (Dordr) ; 27(6): 7679-7698, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35221771

RESUMO

This study uses the technology acceptance model (TAM) to help explain how the use of technology influences learning outcomes emanating from engagement with the Zoom video conference platform. To this end, structural equation modeling was used to analyze the relationships among the TAM variables in reference to Zoom taught during the Covid-19 pandemic. Following a cross-sectional research design, data were collected using Davis's TAM (1989) scales including perceived ease of use (PEoU), perceived usefulness (PU), behavioral intentions, and attitude from 321 South Korean university students attending their 10th week of English as a foreign language (EFL) conversational English classes. Results revealed that seven of the ten proposed hypotheses were confirmed, with path coefficients having small to large effect sizes. Most notably, PEoU with Zoom strongly affected PU and actual use. In addition, PU with Zoom predicted intentions to use Zoom in the future; however, it failed to influence perceived learning outcomes. While PU predicted future use, it did not influence actual use regarding how well students reported their current performance in their video conference course. PEoU with video conference tools was an influential antecedent to usefulness, attitude, and perceived learning outcome. Lastly, two notable instances of mediation through PU occurred. In consideration of findings, students and instructors should be well trained on the use and functionality of video conference software before its implementation in video conference classrooms.

11.
Br Med Bull ; 137(1): 42-50, 2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33710270

RESUMO

INTRODUCTION: This paper reviews the prevalence and health risks of excess sedentary behaviour in office workers, and the effectiveness of sedentary workplace interventions in a manner accessible to practitioners. SOURCES OF DATA: A narrative review of empirical studies obtained from PubMed and Web of Science. AREAS OF AGREEMENT: Office workers are highly sedentary, increasing their risk of health problems. Interventions using individual, organisational and environmental level strategies can be effective for reducing workplace sitting. AREAS OF CONTROVERSY: The effects of sedentary workplace interventions on health are inconsistent. This may be due to a lack of randomized controlled trials powered to detect changes in health outcomes. GROWING POINTS: Multicomponent interventions that use a combination of the strategies above may be the most effective for reducing sitting. AREAS TIMELY FOR DEVELOPING RESEARCH: Determining the long-term health and cost-effectiveness of sedentary workplace interventions is a priority to encourage employer buy-in for their implementation.


Assuntos
Comportamento Sedentário , Local de Trabalho , Análise Custo-Benefício , Humanos , Prevalência , Fatores de Tempo
12.
Transfus Med ; 31(3): 167-175, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33333627

RESUMO

INTRODUCTION: The lack of approved specific therapeutic agents to treat coronavirus disease (COVID-19) associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has led to the rapid implementation of convalescent plasma therapy (CPT) trials in many countries, including the United Kingdom. Effective CPT is likely to require high titres of neutralising antibody (nAb) in convalescent donations. Understanding the relationship between functional neutralising antibodies and antibody levels to specific SARS-CoV-2 proteins in scalable assays will be crucial for the success of a large-scale collection. We assessed whether neutralising antibody titres correlated with reactivity in a range of enzyme-linked immunosorbent assays (ELISA) targeting the spike (S) protein, the main target for human immune response. METHODS: Blood samples were collected from 52 individuals with a previous laboratory-confirmed SARS-CoV-2 infection. These were assayed for SARS-CoV-2 nAbs by microneutralisation and pseudo-type assays and for antibodies by four different ELISAs. Receiver operating characteristic (ROC) analysis was used to further identify sensitivity and specificity of selected assays to identify samples containing high nAb levels. RESULTS: All samples contained SARS-CoV-2 antibodies, whereas neutralising antibody titres of greater than 1:20 were detected in 43 samples (83% of those tested) and >1:100 in 22 samples (42%). The best correlations were observed with EUROimmun immunoglobulin G (IgG) reactivity (Spearman Rho correlation coefficient 0.88; p < 0.001). Based on ROC analysis, EUROimmun would detect 60% of samples with titres of >1:100 with 100% specificity using a reactivity index of 9.1 (13/22). DISCUSSION: Robust associations between nAb titres and reactivity in several ELISA-based antibody tests demonstrate their possible utility for scaled-up production of convalescent plasma containing potentially therapeutic levels of anti-SARS-CoV-2 nAbs.


Assuntos
Anticorpos Neutralizantes/sangue , COVID-19/terapia , SARS-CoV-2/imunologia , Anticorpos Antivirais/sangue , Doadores de Sangue , COVID-19/diagnóstico , Teste para COVID-19 , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Imunização Passiva/métodos , Masculino , Curva ROC , Sensibilidade e Especificidade , Soroterapia para COVID-19
13.
BMC Public Health ; 21(1): 2126, 2021 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-34798842

RESUMO

BACKGROUND: Workplace interventions have shown promise for reducing sitting in office workers. Police office staff remain an understudied population group that work within a disciplined organisation with distinctive work tasks around public safety, potentially affecting their capability, opportunity, and motivation to change sitting behaviour. This study aimed to assess the perceived influences on reducing workplace sitting in non-operational, desk-based police staff in order to derive theoretical determinants for behaviour change. METHODS: Ten police staff from a single police force in Bedfordshire, England [eight female; 39.5 ± 11.5 years] took part in face-to-face semi-structured interviews lasting 46 ± 11 min on average. Thematic analysis identified key themes which were then mapped onto the Theoretical Domains Framework (TDF) and linked to the Capability, Opportunity, Motivation-Behaviour (COM-B) model. RESULTS: Seven themes were identified: 'Work tasks are seated', 'Social norm is to sit', 'Belief in ability to regulate behaviour', 'Knowledge of health risks', 'Organisational support', 'Impact on productivity', and 'Perceived autonomy for sitting reduction'. CONCLUSIONS: Awareness of behaviour and health impacts (Capability), social and physical support to sit less (Opportunity), and habit formation techniques (Motivation) are recommended considerations in sitting reduction workplace interventions for police staff.


Assuntos
Polícia , Postura Sentada , Eficiência , Feminino , Humanos , Motivação , Local de Trabalho
14.
J Sports Sci ; 39(7): 792-800, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33213284

RESUMO

The effects of breaking up sitting with resistance exercise on cardiometabolic health and cognitive function in young healthy adults are unknown. This study evaluated the acute effects of breaking up sitting with bodyweight resistance exercise on postprandial glucose, lipids, blood pressure and cognitive function. A randomised crossover design was used. Twelve normal-weight participants aged 25 ± 6 years took part in two, 5 h conditions: (1) uninterrupted sitting (SIT), and (2) sitting with 3 min of bodyweight resistance exercise breaks every 30 min (REX). Dietary intake was standardised across conditions. Linear mixed models were used to compare outcomes between conditions. Postprandial glucose was significantly higher in the REX condition than in SIT (incremental area under the curve 346.3 [95% confidence interval: 233.9, 458.7] and 256.9 [144.4, 369.3] mmol/L∙5 h, respectively, p = 0.045). Blood pressure, lipids and cognitive function outcomes were not different between conditions (p ≥ 0.05). This study suggests that breaking up sitting with bodyweight resistance exercise does not benefit cardiometabolic health or cognitive function acutely in young healthy adults. The longer-term effects of breaking up sitting with resistance exercise warrants investigation to appropriately inform public health guidelines.


Assuntos
Glicemia/metabolismo , Cognição/fisiologia , Período Pós-Prandial , Treinamento Resistido/métodos , Comportamento Sedentário , Postura Sentada , Adulto , Área Sob a Curva , Pressão Sanguínea , Circulação Cerebrovascular/fisiologia , Estudos Cross-Over , Dieta , Feminino , Humanos , Lipídeos/sangue , Masculino , Memória/fisiologia , Pessoa de Meia-Idade , Tempo de Reação/fisiologia , Fatores de Tempo , Triglicerídeos/sangue , Adulto Jovem
15.
Educ Inf Technol (Dordr) ; 26(3): 2563-2583, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33169066

RESUMO

Intrinsic value is related to intrinsic motivation and influences learners' decisions to begin, continue, and return to learning tasks. In the context of a fully online foreign language English course, we used structural equation modeling to explore the motivation for asynchronous collaborative writing practice, motivation for video-synchronous speaking practice, course satisfaction, and the mediating effect course satisfaction has on behavioral intentions to use language learning technology. Cross-sectional survey results (n = 186) revealed that students who were motivated by asynchronous online collaborative writing were more likely to enjoy online learning in general when compared to students who reported motivation for video-synchronous online speaking practice. Moreover, the relationship between motivation for collaborative writing and behavioral intentions to use language learning technology was mediated by course satisfaction. A follow-up open-ended survey (n = 65) revealed that students held positive views for online second language writing and speaking practice overall but for distinctly different reasons. The findings are discussed in terms of their theoretical implications for modeling e-learning approaches with significance for promoting instructional training effectiveness and transformative learning.

16.
Biochemistry ; 59(23): 2143-2153, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32432457

RESUMO

Biosynthesis of the hydroxamate siderophore aerobactin requires the activity of four proteins encoded within the iuc operon. Recently, we biochemically reconstituted the biosynthetic pathway and structurally characterized IucA and IucC, two enzymes that sequentially couple N6-acetyl-N6-hydroxylysine to the primary carboxylates of citrate. IucA and IucC are members of a family of non-ribosomal peptide synthetase-independent siderophore (NIS) synthetases that are involved in the production of other siderophores, including desferrioxamine, achromobactin, and petrobactin. While structures of several members of this family were solved previously, there is limited mechanistic insight into the reaction catalyzed by NIS synthetases. Therefore, we performed a terreactant steady-state kinetic analysis and herein provide evidence for an ordered mechanism in which the chemistry is preceded by the formation of the quaternary complex. We further probed two regions of the active site with site-directed mutagenesis and identified several residues, including a conserved motif that is present on a dynamic loop, that are important for substrate binding and catalysis.


Assuntos
Proteínas de Bactérias/metabolismo , Vias Biossintéticas , Ácidos Hidroxâmicos/metabolismo , Oxo-Ácido-Liases/metabolismo , Proteínas de Bactérias/química , Ácidos Hidroxâmicos/química , Klebsiella pneumoniae/enzimologia , Modelos Moleculares , Estrutura Molecular , Oxo-Ácido-Liases/química
17.
Environ Sci Technol ; 54(21): 13610-13618, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-32910645

RESUMO

Technetium-99 immobilization in low-temperature nuclear waste forms often relies on additives that reduce environmentally mobile pertechnetate (TcO4-) to insoluble Tc(IV) species. However, this is a short-lived solution unless reducing conditions are maintained over the hazardous life cycle of radioactive wastes (some ∼10,000 years). Considering recent experimental observations, this work explores how rapid formation of ettringite [Ca6Al2(SO4)3(OH)12·26(H2O)], a common mineral formed in cementitious waste forms, may be used to directly immobilize TcO4-. Results from ab initio molecular dynamics (AIMD) simulations and solid-phase characterization techniques, including synchrotron X-ray absorption, fluorescence, and diffraction methods, support successful incorporation of TcO4- into the ettringite crystal structure via sulfate substitution when synthesized by aqueous precipitation methods. One sulfate and one water are replaced with one TcO4- and one OH- during substitution, where Ca2+-coordinated water near the substitution site is deprotonated to form OH- for charge compensation upon TcO4- substitution. Furthermore, AIMD calculations support favorable TcO4- substitution at the SO42- site in ettringite rather than gypsum (CaSO4·2H2O, formed as a secondary mineral phase) by at least 0.76 eV at 298 K. These results are the first of their kind to suggest that ettringite may contribute to TcO4- immobilization and the overall lifetime performance of cementitious waste forms.


Assuntos
Resíduos Radioativos , Pertecnetato Tc 99m de Sódio , Minerais , Sulfatos
18.
Scand J Med Sci Sports ; 30(8): 1398-1408, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32243644

RESUMO

Elevated levels of cardiovascular disease (CVD) risk markers are highly prevalent in people with a spinal cord injury (SCI). Breaking up prolonged sedentary time with short, regular bouts of physical activity can reduce postprandial glucose and lipid levels in able-bodied individuals. The effects in people with paraplegia are unknown. The study aims were to examine the acute postprandial glucose (primary aim), lipid, blood pressure, and psychological responses (secondary aims) to breaking up prolonged sedentary time in individuals with paraplegia. This was a randomized crossover design trial. Fourteen participants with paraplegia (age 51 ± 9 years, trunk fat mass 44.3 ± 7.7%) took part in the following two, 5.5-hour conditions: (1) uninterrupted sedentary time (SED), and (2) sedentary time interrupted with 2 minutes of moderate-intensity arm crank ergometer physical activity every 20 minutes (SED-ACT). Standardized breakfast and lunch test meals were consumed during each condition. The outcomes were compared between conditions using linear mixed models. Glucose area under the curve (AUC) was significantly lower during the lunch postprandial period in SED-ACT vs SED (incremental AUC 1.9 [95% CI 1.0, 2.7) and 3.0 [2.1, 3.9] mmol/L∙2.5 hour, respectively, P = .015, f = 0.34). There were no differences between conditions for the breakfast or total 5.5 hours postprandial periods (P > .05). Positive affect was higher in SED-ACT than SED (P = .001). Breaking up prolonged sedentary time acutely attenuates lunch postprandial glucose and improves positive affect in people with paraplegia. This may have clinical relevance for reducing CVD risk and improving psychological well-being in this population.


Assuntos
Glicemia/metabolismo , Doenças Cardiovasculares/prevenção & controle , Exercício Físico/fisiologia , Paraplegia , Comportamento Sedentário , Adulto , Pressão Sanguínea/fisiologia , Estudos Cross-Over , Feminino , Fatores de Risco de Doenças Cardíacas , Humanos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial
19.
Br J Sports Med ; 54(6): 326-331, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29875278

RESUMO

OBJECTIVE: To establish the meaning of the term 'adherence' (including conceptual and measurement definitions) in the context of therapeutic exercise (TE) for musculoskeletal (MSK) pain. DESIGN: Systematic review using a search strategy including terms for: adherence, TE and MSK pain. Identified studies were independently screened for inclusion by two researchers. Two independent researchers extracted data on: study type; MSK pain population; type of TE used; definitions, parameters, measurement methods and values of adherence. DATA SOURCES: Seven electronic databases were searched from inception to December 2016. ELIGIBILITY CRITERIA: Any study type featuring TE for adults with MSK pain and containing a definition of adherence, or a description of how adherence was measured. RESULTS: 459 studies were identified and 86 were included in the review. Most were prospective cohort studies and featured back and/or neck pain. Strengthening and stretching were the most common types of TE. A clearly identifiable definition of adherence was provided in 40% of the studies, with 12% using the same definition. Exercise frequency was the most commonly measured parameter of adherence, with self-report logs the most common measurement method. The most common value range used to determine satisfactory adherence was 80%-99% of the recommended exercise dose. CONCLUSION: No single definition of adherence to TE was apparent. We found no definition of adherence that specifically related to TE for MSK pain or described the dimensions of TE that should be measured. We recommend conceptualising adherence to TE for MSK pain from the perspective of all relevant stakeholders.


Assuntos
Terapia por Exercício , Dor Musculoesquelética/terapia , Cooperação do Paciente , Adulto , Dor nas Costas/terapia , Terapia por Exercício/métodos , Humanos , Exercícios de Alongamento Muscular , Cervicalgia/terapia , Treinamento Resistido , Autorrelato
20.
J Biol Chem ; 293(20): 7841-7852, 2018 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-29618511

RESUMO

Aerobactin, a citryl-hydroxamate siderophore, is produced by a number of pathogenic Gram-negative bacteria to aid in iron assimilation. Interest in this well-known siderophore was reignited by recent investigations suggesting that it plays a key role in mediating the enhanced virulence of a hypervirulent pathotype of Klebsiella pneumoniae (hvKP). In contrast to classical opportunistic strains of K. pneumoniae, hvKP causes serious life-threatening infections in previously healthy individuals in the community. Multiple contemporary reports have confirmed fears that the convergence of multidrug-resistant and hvKP pathotypes has led to the evolution of a highly transmissible, drug-resistant, and virulent "super bug." Despite hvKP harboring four distinct siderophore operons, knocking out production of only aerobactin led to a significant attenuation of virulence. Herein, we continue our structural and functional studies on the biosynthesis of this crucial virulence factor. In vivo heterologous production and in vitro reconstitution of aerobactin biosynthesis from hvKP was carried out, demonstrating the specificity, stereoselectivity, and kinetic throughput of the complete pathway. Additionally, we present a steady-state kinetic analysis and the X-ray crystal structure of the second aerobactin synthetase IucC, as well as describe a surface entropy reduction strategy that was employed for structure determination. Finally, we show solution X-ray scattering data that support a unique dimeric quaternary structure for IucC. These new insights into aerobactin assembly will help inform potential antivirulence strategies and advance our understanding of siderophore biosynthesis.


Assuntos
Ácidos Hidroxâmicos/química , Klebsiella pneumoniae/enzimologia , Oxo-Ácido-Liases/química , Sideróforos/química , Fatores de Virulência/química , Domínio Catalítico , Clonagem Molecular , Cristalografia por Raios X , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Ácidos Hidroxâmicos/metabolismo , Cinética , Infecções por Klebsiella/microbiologia , Infecções por Klebsiella/patologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/patogenicidade , Modelos Moleculares , Oxo-Ácido-Liases/genética , Oxo-Ácido-Liases/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Estrutura Quaternária de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sideróforos/biossíntese , Sideróforos/genética , Especificidade por Substrato , Termodinâmica , Fatores de Virulência/biossíntese , Fatores de Virulência/genética
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