329 research outputs found

    Polymorphisms in the circadian expressed genes PER3 and ARNTL2 are associated with diurnal preference and GNβ3 with sleep measures

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    Sleep and circadian rhythms are intrinsically linked, with several sleep traits, including sleep timing and duration, influenced by both sleep homeostasis and the circadian phase. Genetic variation in several circadian genes has been associated with diurnal preference (preference in timing of sleep), although there has been limited research on whether they are associated with other sleep measurements. We investigated whether these genetic variations were associated with diurnal preference (Morningness-Eveningness Questionnaire) and various sleep measures, including: the global Pittsburgh Sleep Quality index score; sleep duration; and sleep latency and sleep quality. We genotyped 10 polymorphisms in genes with circadian expression in participants from the G1219 sample (n = 966), a British longitudinal population sample of young adults. We conducted linear regressions using dominant, additive and recessive models of inheritance to test for associations between these polymorphisms and the sleep measures. We found a significant association between diurnal preference and a polymorphism in period homologue 3 (PER3) (P < 0.005, recessive model) and a novel nominally significant association between diurnal preference and a polymorphism in aryl hydrocarbon receptor nuclear translocator-like 2 (ARNTL2) (P < 0.05, additive model). We found that a polymorphism in guanine nucleotide binding protein beta 3 (GNβ3) was associated significantly with global sleep quality (P < 0.005, recessive model), and that a rare polymorphism in period homologue 2 (PER2) was associated significantly with both sleep duration and quality (P < 0.0005, recessive model). These findings suggest that genes with circadian expression may play a role in regulating both the circadian clock and sleep homeostasis, and highlight the importance of further studies aimed at dissecting the specific roles that circadian genes play in these two interrelated but unique behaviours

    Flow field visualization of entangled polybutadiene solutions under nonlinear viscoelastic flow conditions

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    Using self-designed particle visualization instrumentation, startup shear and step-strain tests were conducted under a series of systematically varied rheological and geometrical conditions, and the velocity profiles in three different well-entangled polybutadiene/oligomer solutions were obtained. For startup shear tests, in the regime of entanglement densities up to 89 and nominal reptation Weissenberg numbers up to 18.6, we generally observe either wall slip and a linear velocity/strain profile or simply the linear profile with no wall slip unless a massive edge fracture or instability has occurred in the sample. Meanwhile, step-strain tests conducted at similar and higher step Weissenberg numbers revealed little particle motion upon cessation. These results lead us to a conclusion that there is no compelling evidence of shear banding or nonquiescent relaxation in the range of entanglement density and Wi investigated; we interpret the results to imply that any observed banding probably correlates with edge effects.National Science Foundation (U.S.) (Grant DMR-0934305

    The validity of US nutritional surveillance: USDA's loss-adjusted food availability data series 1971-2010

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    The purpose of this study was to examine the validity of the 1971-2010 United States Department of Agriculture’s (USDA’s) loss-adjusted food availability (LAFA) per capita caloric consumption estimates. Estimated total daily energy expenditure (TEE) was calculated for nationally representative samples of US adults, 20-74 years, using the Institute of Medicine’s predictive equations with “low-active” (TEE L-ACT) and “sedentary” (TEE SED) physical activity values. TEE estimates were subtracted from LAFA estimates to create disparity values (kcal/d). A validated mathematical model was applied to calculate expected weight change in reference individuals resulting from the disparity. From 1971-2010, the disparity between LAFA and TEE L-ACT varied by 394 kcal/d—(P < 0.001), from −205 kcal/d (95% CI: −214, −196) to +189 kcal/d (95% CI: 168, 209). The disparity between LAFA and TEE SED varied by 412 kcal/d (P < 0.001), from −84 kcal/d (95% CI: −93, −76) to +328 kcal/d (95% CI: 309, 348). Our model suggests that if LAFA estimates were actually consumed, reference individuals would have lost ~1-4 kg/y from 1971-1980 (an accumulated loss of ~12 to ~36 kg), and gained ~3-7 kg/y from 1988-2010 (an accumulated gain of ~42 to ~98 kg). These estimates differed from the actual measured increments of 10 kg and 9 kg in reference men and women, respectively, over the 39-year period. The USDA LAFA data provided inconsistent, divergent estimates of per capita caloric consumption over its 39-year history. The large, variable misestimation suggests that the USDA LAFA per capita caloric intake estimates lack validity and should not be used to inform public policy

    Anesthesiologists' and surgeons' perceptions about routine pre-operative testing in low risk patients: application of the Theoretical Domains Framework to identify factors that influence physicians' decisions to order pre-operative tests

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    Background Routine pre-operative tests for anesthesia management are often ordered by both anesthesiologists and surgeons for healthy patients undergoing low-risk surgery. The Theoretical Domains Framework (TDF) was developed to investigate determinants of behaviour and identify potential behaviour change interventions. In this study, the TDF is used to explore anaesthesiologists’ and surgeons’ perceptions of ordering routine tests for healthy patients undergoing low-risk surgery. Conclusion We identified key factors that anesthesiologists and surgeons believe influence whether they order pre-operative tests routinely for anesthesia management for a healthy adults undergoing low-risk surgery. These beliefs identify potential individual, team, and organisation targets for behaviour change interventions to reduce unnecessary routine test ordering. Methods Sixteen clinicians (eleven anesthesiologists and five surgeons) throughout Ontario were recruited. An interview guide based on the TDF was developed to identify beliefs about preoperative testing practices. Content analysis of physicians’ statements into the relevant theoretical domains was performed. Specific beliefs were identified by grouping similar utterances of the interview participants. Relevant domains were identified by noting the frequencies of the beliefs reported, presence of conflicting beliefs, and perceived influence on the performance of the behaviour under investigation. Results Seven of the twelve domains were identified as likely relevant to changing clinicians’ behaviour about pre-operative test ordering for anesthesia management. Key beliefs were identified within these domains including: conflicting comments about who was responsible for the test-ordering (Social/professional role and identity); inability to cancel tests ordered by fellow physicians (Beliefs about capabilities and social influences); and the problem with tests being completed before the anesthesiologists see the patient (Beliefs about capabilities and Environmental context and resources). Often, tests were ordered by an anesthesiologist based on who may be the attending anesthesiologist on the day of surgery while surgeons ordered tests they thought anesthesiologists may need (Social influences). There were also conflicting comments about the potential consequences associated with reducing testing, from negative (delay or cancel patients’ surgeries), to indifference (little or no change in patient outcomes), to positive (save money, avoid unnecessary investigations) (Beliefs about consequences). Further, while most agreed that they are motivated to reduce ordering unnecessary tests (Motivation and goals), there was still a report of a gap between their motivation and practice (Behavioural regulation)

    The effect of luminal content and rate of occlusion on the interpretation of colonic manometry

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    This is the accepted version of the following article: [Arkwright, J. W., Dickson, A., Maunder, S. A., Blenman, N. G., Lim, J., O’Grady, G., Archer, R., Costa, M., Spencer, N. J., Brookes, S., Pullan, A. and Dinning, P. G. (2013), The effect of luminal content and rate of occlusion on the interpretation of colonic manometry. Neurogastroenterology & Motility, 25: e52–e59.], which has been published in final form at [http://dx.doi.org/10.1111/nmo.12051]. In addition, authors may also transmit, print and share copies with colleagues, provided that there is no systematic distribution of the submitted version, e.g. posting on a listserve, network or automated delivery.Background Manometry is commonly used for diagnosis of esophageal and anorectal motility disorders. In the colon, manometry is a useful tool, but clinical application remains uncertain. This uncertainty is partly based on the belief that manometry cannot reliably detect non-occluding colonic contractions and, therefore, cannot identify reliable markers of dysmotility. This study tests the ability of manometry to record pressure signals in response to non-lumen-occluding changes in diameter, at different rates of wall movement and with content of different viscosities. Methods A numerical model was built to investigate pressure changes caused by localized, non-lumen-occluding reductions in diameter, similar to those caused by contraction of the gut wall. A mechanical model, consisting of a sealed pressure vessel which could produce localized reductions in luminal diameter, was used to validate the model using luminal segments formed from; (i) natural latex; and (ii) sections of rabbit proximal colon. Fluids with viscosities ranging from 1 to 6800 mPa s-1 and luminal contraction rates over the range 5-20 mmHg s-1 were studied. Key Results Manometry recorded non-occluding reductions in diameter, provided that they occurred with sufficiently viscous content. The measured signal was linearly dependent on the rate of reduction in luminal diameter and also increased with increasing viscosity of content (R2 = 0.62 and 0.96 for 880 and 1760 mPa s-1, respectively). Conclusions & Inferences Manometry reliably registers non-occluding contractions in the presence of viscous content, and is therefore a viable tool for measuring colonic motility. Interpretation of colonic manometric data, and definitions based on manometric results, must consider the viscosity of luminal content.Australian National Health & Medical Research Counci

    Bringing History into the Study of Routines: Contextualizing Performance

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    The focus on routines as ‘generative systems’ often portrays them as patterns of action relatively divorced from their context. History can help to supply a deeper and richer context, showing how routines are connected to broader structural and cultural factors. But it also shows that routines themselves have a history. This is explored using the illustration of the history of one particular organizational routine, that of the visitation of local organizational units by central church bodies, in three times and places: fifteenth century Italy, eighteenth century England and eighteenth century Scotland. This illustration shows that similar routines can be found but these are given very different inflections by the broader social, cultural and political context. Attention is drawn in particular to the differential involvement of lay actors and the implications for broader impacts. The case is made for analytical narratives of emergence of routines which can reconnect organizational routines both with their own history and with their broader context

    Highly Sensitive and Specific Detection of Rare Variants in Mixed Viral Populations from Massively Parallel Sequence Data

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    Viruses diversify over time within hosts, often undercutting the effectiveness of host defenses and therapeutic interventions. To design successful vaccines and therapeutics, it is critical to better understand viral diversification, including comprehensively characterizing the genetic variants in viral intra-host populations and modeling changes from transmission through the course of infection. Massively parallel sequencing technologies can overcome the cost constraints of older sequencing methods and obtain the high sequence coverage needed to detect rare genetic variants (<1%) within an infected host, and to assay variants without prior knowledge. Critical to interpreting deep sequence data sets is the ability to distinguish biological variants from process errors with high sensitivity and specificity. To address this challenge, we describe V-Phaser, an algorithm able to recognize rare biological variants in mixed populations. V-Phaser uses covariation (i.e. phasing) between observed variants to increase sensitivity and an expectation maximization algorithm that iteratively recalibrates base quality scores to increase specificity. Overall, V-Phaser achieved >97% sensitivity and >97% specificity on control read sets. On data derived from a patient after four years of HIV-1 infection, V-Phaser detected 2,015 variants across the ∼10 kb genome, including 603 rare variants (<1% frequency) detected only using phase information. V-Phaser identified variants at frequencies down to 0.2%, comparable to the detection threshold of allele-specific PCR, a method that requires prior knowledge of the variants. The high sensitivity and specificity of V-Phaser enables identifying and tracking changes in low frequency variants in mixed populations such as RNA viruses

    Factors that predict early treatment failure for patients with locally advanced (T4) breast cancer

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    Locally advanced breast cancer (LABC) is associated with dire prognosis despite progress in multimodal treatments. We evaluated several clinical and pathological features of patients with either noninflammatory (NIBC, cT4a-c) or inflammatory (IBC, cT4d) breast cancer to identify subset groups of patients with high risk of early treatment failure. Clinical and pathological features of 248 patients with LABC, who were treated with multimodality treatments including neoadjuvant chemotherapy followed by radical surgery and radiotherapy were reassessed. Tumour samples obtained at surgery were evaluated using standard immunohistochemical methods. Overall, 141 patients (57%) presented with NIBC (cT4a-c, N0-2, M0) and 107 patients (43%) with IBC (cT4d, N0-2, M0). Median follow-up time was 27.5 months (range: 1.6–87.8). No significant difference in terms of recurrence-free survival (RFS) (P=0.72), disease-free survival (DFS) (P=0.98) and overall survival (OS) (P=0.35) was observed between NIBC and IBC. At the multivariate analysis, patients with ER- and PgR-negative diseases had a significantly worse RFS than patients with ER- and/or PgR-positive diseases (hazard ratio: 2.47, 95% CI: 1.33–4.59 for overall). The worst RFS was observed for the subgroup of patients with endocrine nonresponsive and HER2-negative breast cancer (2-year RFS: 57% in NIBC and 57% in IBC) A high Ki-67 labelling index (>20% of the invasive tumour cells) and the presence of peritumoral vascular invasion (PVI) significantly correlated with poorer RFS in overall (HR 2.69, 95% CI: 1.61–4.50 for Ki-67>20% and HR 2.27, 95% CI: 1.42–3.62 for PVI). Patients with endocrine nonresponsive LABC had the most dire treatment outcome. High degree of Ki-67 staining and presence of PVI were also indicators of higher risk of early relapse. These factors should be considered in therapeutic algorithms for LABC
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