6,481 research outputs found

    Equine digital tendons show breed‐specific differences in their mechanical properties that may relate to athletic ability and predisposition to injury

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    Background Throughout the ages, human subjects have selected horse breeds for their locomotor capacities. Concurrently, tissue properties may have diversified because of specific requirements of different disciplines. Objectives The aim of this study was to compare the biomechanical properties of tendons with different functions between equine breeds traditionally selected for racing or sport. Study design This study used ex vivo tendons and compared the mechanical properties of the common digital extensor tendon (CDET) and superficial digital flexor tendon (SDFT) between racehorses (Thoroughbred [TB]) and sports horses (Friesian Horse [FH], Warmblood [WB]). Methods The SDFT and CDET of FH (n = 12), WBs (n = 12) and TBs (n = 8) aged 3-12 years were harvested. The cross sectional area (cm(2)), maximal load (N), ultimate strain (%), ultimate stress (MPa) and elastic modulus (MPa) were determined and tested for significant differences between the breeds (P<0.05). Results The SDFT from WB horses had a significantly lower elastic modulus than TB horses and failed at a higher strain and load than both FHs and TBs. The mechanical properties of the CDET did not differ between breeds. In agreement with previous studies, the CDET failed at a higher stress and had a higher elastic modulus than the SDFT and, for the WB group of horses only, failed at a significantly lower strain. Interestingly, the mode of failure differed between breeds, particularly with respect to the FHs. Main limitations The exercise history of horses used in this study was unknown and the age-range was relatively large; both these factors may have influenced the absolute properties reported in this study. Conclusions This study shows for the first time that mechanical properties of the SDFT differ between breeds. These properties are likely to be related to selection for high-speed vs. an extravagant elastic gait and may be an important indicator of performance ability. The is available in Spanish - see Supporting Informatio

    SDO/HMI survey of emerging active regions for helioseismology

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    Observations from the Solar Dynamics Observatory (SDO) have the potential for allowing the helioseismic study of the formation of hundreds of active regions, which would enable us to perform statistical analyses. Our goal is to collate a uniform data set of emerging active regions observed by the SDO/HMI instrument suitable for helioseismic analysis up to seven days before emergence. We restricted the sample to active regions that were visible in the continuum and emerged into quiet Sun largely avoiding pre-existing magnetic regions. As a reference data set we paired a control region (CR), with the same latitude and distance from central meridian, with each emerging active region (EAR). We call this data set, which is currently comprised of 105 emerging active regions observed between May 2010 and November 2012, the SDO Helioseismic Emerging Active Region (SDO/HEAR) survey. To demonstrate the utility of a data set of a large number of emerging active regions, we measure the relative east-west velocity of the leading and trailing polarities from the line-of-sight magnetogram maps during the first day after emergence. The latitudinally averaged line-of-sight magnetic field of all the EARs shows that, on average, the leading (trailing) polarity moves in a prograde (retrograde) direction with a speed of 121 +/- 22 m/s (-70 +/- 13 m/s) relative to the Carrington rotation rate in the first day. However, relative to the differential rotation of the surface plasma, the east-west velocity is symmetric, with a mean of 95 +/- 13 m/s. The SDO/HEAR data set will not only be useful for helioseismic studies, but will also be useful to study other features such as the surface magnetic field evolution of a large sample of EARs.Comment: Accepted by Astronomy and Astrophysics, 11 figures, one longtable; update corrects units in Figure

    Moderators of the association between regular smoking exposure and motivation and attempts to quit: a repeat cross‐sectional study

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    AIMS: To estimate the associations between regular exposure to smoking by other people and motivation and attempts to quit among current smokers. To examine whether socio-demographic and other factors moderate these associations. DESIGN: A repeat nationally representative cross-sectional survey. Data were collected monthly between November 2014 and February 2019. SETTING: England. PARTICIPANTS: Current smokers aged ≥ 16 years from the Smoking Toolkit Study (N=15,136). MEASUREMENTS: Participants were asked whether other people regularly smoke in their presence, how motivated they were to quit, and whether they had made a quit attempt in the past year. Moderators assessed were occupation-based social grade, housing tenure, urges to smoke, high-risk alcohol consumption, and disability. Adjusted analyses included moderators, socio-demographic (age/sex/ethnicity/sexual orientation/marital status/children in household) and seasonal (quarter/year) confounders. FINDINGS: Current smokers who were regularly exposed to other people smoking in their presence were less likely to be highly motivated to quit (odds ratio = 0.88 [95%CI 0.80-0.97]), but were no less likely to have made a quit attempt in the past year (OR 1.04 [0.97-1.13], Bayes Factor (BF) = 0.05). The inverse relationship between regular smoking exposure and motivation to quit was moderated by urges to smoke, such that exposure was only associated with a reduction in motivation among those without strong urges to smoke (OR 0.83 [0.75-0.93] versus OR 1.04 [0.86-1.26]; p = .048). None of the other factors significantly moderated the association with motivation to quit, and none moderated the relationship between regular smoking exposure and quit attempts. All non-significant interactions, except social grade (BF = 1.44) with quit attempts, had Bayes Factors that supported the hypothesis of no moderation (BF range: 0.12-0.21). CONCLUSIONS: Among current smokers in England, regular exposure to other smokers appears to be associated with lower motivation to quit in people without strong urges to smoke, yet there appears to be no association with quit attempts in the previous year. Social grade, housing tenure, high-risk alcohol consumption and disability do not moderate these associations

    Cutting down, quitting and motivation to stop smoking by self-reported COVID-19 status: Representative cross-sectional surveys in England.

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    To examine the association of self-reported COVID-19 disease status with cutting down, past-month and past-year quit attempts and motivation to stop smoking. Repeat cross-sectional survey, representative of the adult population in England. Past-year smokers, n = 3338 (aged ≥ 18 years) responding between May 2020 and April 2021. Outcomes were (i) currently cutting down, (ii) having made a quit attempt in the past month, (iii) having made a quit attempt in the past year and (iv) motivation to stop smoking. The explanatory variable was self-reported COVID-19 disease status (belief in never versus ever had COVID-19). Covariates included age, sex, occupational grade, region, children in the household, alcohol use and survey month. Of past-year smokers, 720 (21.6%) reported past-COVID-19 infection and 48 (1.4%) reported current COVID-19 infection. In adjusted analyses, rates of currently cutting down [adjusted odds ratio (aOR) = 1.12, 95% confidence interval (CI) = 0.93-1.34], past-year quit attempts (aOR = 0.99, 95% CI = 0.82-1.19) and motivation to stop smoking (aOR = 1.04, 95% CI = 0.89-1.23) were comparable in those who did and did not report ever having had COVID-19. People who reported ever having had COVID-19 had 39% higher odds than those without of attempting to quit in the past month, but the confidence interval contained the possibility of no difference (aOR = 1.39, 95% CI = 0.94-2.06) and for some the quit attempt may have occurred before they had COVID-19. During the first year of the COVID-19 pandemic in England, rates of reducing smoking and attempting to quit in the past year were similar in smokers who did or did not self-report ever having had COVID-19. There was also little difference in motivation to stop smoking between groups. However, causal interpretation is limited by the study design, and there is potential misclassification of the temporal sequence of infection and changes to smoking behaviour. [Abstract copyright: © 2022 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

    Trends in use of e-cigarette device types and heated tobacco products from 2016 to 2020 in England

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    This study examined use trends of e-cigarette devices types, heated tobacco products (HTPs) and e-liquid nicotine concentrations in England from 2016 to 2020. Data were from a representative repeat cross-sectional survey of adults aged 16 or older. Bayesian logistic regression was used to estimate proportions and 95% credible intervals (CrIs). Of 75,355 participants, 5.3% (weighted = 5.5%) were currently using e-cigarettes or HTPs, with the majority (98.7%) using e-cigarettes. Among e-cigarette users, 53.7% (CrI 52.0–55.1%) used tank devices, 23.7% (22.4–25.1%) mods, 17.3% (16.1–18.4%) pods, and 5.4% (4.7–6.2%) disposables. Tanks were the most widely used device type throughout 2016–2020. Mods were second until 2020, when pods overtook them. Among all e-cigarette/HTP users, prevalence of HTP use remains rare (3.4% in 2016 versus 4.2% in 2020), whereas JUUL use has risen from 3.4% in 2018 to 11.8% in 2020. Across all years, nicotine concentrations of ≤ 6 mg/ml were most widely (41.0%; 39.4–42.4%) and ≥ 20 mg/ml least widely used (4.1%; 3.4–4.9%). Among e-cigarette/HTP users, ex-smokers were more likely than current smokers to use mod and tank e-cigarettes, but less likely to use pods, disposables, JUUL and HTPs. In conclusion, despite growing popularity of pods and HTPs worldwide, refillable tank e-cigarettes remain the most widely used device type in England

    A first-principles comparison of the electronic properties of MgC_{y}Ni_{3} and ZnC_{y}Ni_{3} alloys

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    First-principles, density-functional-based electronic structure calculations are employed to study the changes in the electronic properties of ZnC_{y}Ni_{3} and MgC_{y}Ni_{3} using the Korringa-Kohn-Rostoker coherent-potential approximation method in the atomic sphere approximation (KKR-ASA CPA). As a function of decreasing C at%, we find a steady decrease in the lattice constant and bulk modulus in either alloys. However, the pressure derivative of the bulk modulus displays an opposite trend. Following the Debye model, which relates the pressure derivative of the bulk modulus with the average phonon frequency of the crystal, it can thus be argued that ZnCNi_{3} and its disordered alloys posses a different phonon spectra in comparison to its MgCNi_{3} counterparts. This is further justified by the marked similarity we find in the electronic structure properties such as the variation in the density of states and the Hopfield parameters calculated for these alloys. The effects on the equation of state parameters and the density of states at the Fermi energy, for partial replacement of Mg by Zn are also discussed.Comment: 19 pages, 15 figure

    Preferential sites for intramolecular glucosepane cross-link formation in type I collagen: A thermodynamic study

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    The extracellular matrix (ECM) undergoes progressive age-related stiffening and loss of proteolytic digestibility due to an increase in concentration of advanced glycation end products (AGEs). The most abundant AGE, glucosepane, accumulates in collagen with concentrations over 100 times greater than all other AGEs. Detrimental collagen stiffening properties are believed to play a significant role in several age-related diseases such as osteoporosis and cardiovascular disease. Currently little is known of the potential location of covalently cross-linked glucosepane formation within collagen molecules; neither are there reports on how the respective cross-link sites affect the physical and biochemical properties of collagen. Using fully atomistic molecular dynamics simulations (MD) we have identified six sites where the formation of a covalent intra-molecular glucosepane cross-link within a single collagen molecule in a fibrillar environment is energetically favourable. Identification of these favourable sites enables us to align collagen cross-linking with experimentally observed changes to the ECM. For example, formation of glucosepane was found to be energetically favourable within close proximity of the Matrix Metalloproteinase-1 (MMP1) binding site, which could potentially disrupt collagen degradation.fals

    Comparing identity, attitudes, and indicators of effectiveness in people who smoke, vape or use heated tobacco products: a cross-sectional study

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    Background: There is limited long-term and independent research on heated tobacco products (HTPs). We compared people who used HTPs with those who used nicotine vaping products (NVP) or cigarettes on smoker identity, indicators of effectiveness and, among NVP/HTP users, perceptions of these products. Methods: Adults exclusive cigarette smokers (N=45) and ex-smokers with medium/long-term (>3months) NVP (N=46) or HTP use (N=45) were recruited in London, UK. Participants completed a questionnaire assessing socio-demographics, smoking characteristics, smoker identity, dependence, intention to stop and attitudes towards HTP/NVP. Results: In adjusted analysis, people who used cigarettes (Mean Difference (MD)=1.4, 95%Confidence Intervals (CI) 0.7,2.0) and HTPs (MD=0.8, 95%CI 0.1,1.5) reported stronger smoker identities than those who used NVPs. Compared with smokers, HTP/NVP users had lower cravings for cigarettes (MD=3.0, 95%CI 1.6,4.3; MD=3.1, 95%CI 1.9,4.3, respectively), and higher intention to stop product use (MD=-0.8, 95%CI -1.7,-0.01; MD=-1.2, 95%CI -2.0,-0.3, respectively). People using HTPs or NVPs reported similar perceived product satisfaction (HTP:M=3.4, 95%CI 2.8,3.9; NVP:M=3.0, 95%CI 2.5,3.5), efficacy for smoking cessation (HTP:M=4.5, 95%CI 4.2,4.9; NVP:M=4.6, 95%CI 4.3,4.9) and safety (HTP:M=2.1, 95%CI 2.0,2.2; NVP:M=2.0, 95%CI 1.8,2.1). HTP users reported greater perceived addictiveness than NVPs (MD=0.3, 95%CI 0.2,0.6). Conclusions: HTP and NVP users perceived products to be similarly acceptable and effective suggesting that HTPs, like NVPs, may support smoking cessation. However, since HTP use appears to maintain a stronger smoker identity and perceived addiction, this may suggest a more limited role of HTP for a permanent transition away from cigarettes

    Differences between ethnic groups in self-reported use of e-cigarettes and nicotine replacement therapy for cutting down and temporary abstinence: A cross-sectional population-level survey in England

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    Background and aims: The National Institute for Health and Care Excellence (NICE) has called for research into tobacco harm reduction across ethnicities, genders and socio-economic status. Although there is increasing research focused on the latter two, relatively few studies have considered ethnic variations. Therefore this study aimed to assess (i) the association between ethnicity and use of e-cigarettes and nicotine replacement therapy (NRT) for temporary abstinence and cutting down, and (ii) trends in prevalence of these over time. Design: Repeated cross-sectional household survey. Setting: England. Participants: Between April 2013 and September 2019, data were collected on 24 114 smokers, 16+ of age, taking part in the Smoking Toolkit Study (STS). Measurements: Ethnicity coding included: White, mixed/multiple ethnic group, Asian, Black and Arab/other ethnic group. Smokers reported whether they were currently using e-cigarettes and/or NRT for cutting down or during periods of temporary abstinence. Findings: Odds of e-cigarette use for cutting down and temporary abstinence were significantly lower among those of Asian ethnicity (OR = 0.79, 95% CI = 0.66–0.93) and Arab/other ethnicity (OR = 0.58, 95% CI = 0.40–0.83) compared with White ethnicity. Those of mixed/multiple ethnicity had higher odds for NRT us (OR = 1.42, 95% CI = 1.04–1.94) compared with those of White ethnicity. Trend analysis indicated that for White ethnicity, e-cigarette use by smokers for cutting down and temporary abstinence followed an ‘inverse S’ shaped cubic curve indicating an overall rise, whereas NRT use followed an ‘S’ shaped cubic curve, indicating an overall decline. For mixed/multiple ethnicity a similar trend was found for NRT use only, with other ethnicities showing no statistically significant trends (suggesting relative stability over time). Conclusions: In England, e-cigarette use by smokers for cutting down and temporary abstinence is less common among Asian and Arab/other ethnicity smokers compared with White smokers. Smokers of mixed/multiple ethnicity are the most likely to be using NRT compared with other ethnic groups for cutting down and temporary abstinence. E-cigarette use by smokers for cutting down and temporary abstinence has increased over time among White smokers, whereas prevalence in other ethnic groups has remained stable
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