Layer formation and relaminarisation in plane Couette flow with spanwise stratification

Recent research has shed light on the role of coherent structures in forming layers when stably stratified turbulence is forced with horizontal shear (Lucas, Caulfield & Kerswell, J. Fluid Mech., vol. 832, 2017, pp. 409-437). Here we extend our previous work to investigate the effect of rigid boundaries on the dynamics by studying stably-stratified plane Couette flow with gravity oriented in the spanwise direction. We observe near-wall layering and associated new mean flows in the form of large scale spanwise-flattened streamwise rolls. The layers exhibit the expected buoyancy scaling $l_z\sim U/N$ where $U$ is a typical horizontal velocity scale and $N$ the buoyancy frequency. We associate the new coherent structures with a stratified modification of the well-known large scale secondary flow in plane Couette and find that the possibility of the transition to sustained turbulence is controlled by the relative size of this buoyancy scale to the spanwise spacing of the streaks. We also investigate the influence on the transition to turbulence of the newly discovered linear instability in this system (Facchini et. al. 2018 arXiv:1711.11312).EPSR

Momentum relaxation from the fluid/gravity correspondence

We provide a hydrodynamical description of a holographic theory with broken translation invariance. We use the fluid/gravity correspondence to systematically obtain both the constitutive relations for the currents and the Ward identity for momentum relaxation in a derivative expansion. Beyond leading order in the strength of momentum relaxation, our results differ from a model previously proposed by Hartnoll et al. As an application of these techniques we consider charge and heat transport in the boundary theory. We derive the low frequency thermoelectric transport coefficients of the holographic theory from the linearised hydrodynamics.Comment: 19 pages + appendix, v2: references added, typos corrected, v3: version published in JHE

Attachment styles and personal growth following romantic breakups: The mediating roles of distress, rumination, and tendency to rebound

© 2013 Marshall et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.The purpose of this research was to examine the associations of attachment anxiety and avoidance with personal growth following relationship dissolution, and to test breakup distress, rumination, and tendency to rebound with new partners as mediators of these associations. Study 1 (N = 411) and Study 2 (N = 465) measured attachment style, breakup distress, and personal growth; Study 2 additionally measured ruminative reflection, brooding, and proclivity to rebound with new partners. Structural equation modelling revealed in both studies that anxiety was indirectly associated with greater personal growth through heightened breakup distress, whereas avoidance was indirectly associated with lower personal growth through inhibited breakup distress. Study 2 further showed that the positive association of breakup distress with personal growth was accounted for by enhanced reflection and brooding, and that anxious individuals’ greater personal growth was also explained by their proclivity to rebound. These findings suggest that anxious individuals’ hyperactivated breakup distress may act as a catalyst for personal growth by promoting the cognitive processing of breakup-related thoughts and emotions, whereas avoidant individuals’ deactivated distress may inhibit personal growth by suppressing this cognitive work

Anti-Allergic Cromones Inhibit Histamine and Eicosanoid Release from Activated Human and Murine Mast Cells by Releasing Annexin A1

PMCID: PMC3601088This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Derivation and External Validation of a Prediction Rule for Five-Year Mortality in Patients With Early Diffuse Cutaneous Systemic Sclerosis

OBJECTIVE: Although diffuse cutaneous systemic sclerosis (dcSSc) is associated with a reduction in life expectancy, there are no validated prognostic models for determining 5-year mortality in patients with dcSSc. The objective of this study was to derive and validate a rule for predicting 5-year mortality in patients with early dcSSc. METHODS: We studied an inception cohort of 388 US Caucasian patients with early dcSSc (<2 years from the appearance of the first symptom). Predefined baseline variables were analyzed in a stepwise logistic regression model in order to identify factors independently associated with 5-year all-cause mortality. We rounded the beta weights to the nearest integer and summed the points assigned to each variable in order to stratify patients into low-risk (<0 points), moderate-risk (1-2 points), and high-risk (≥3 points) groups. We then applied this rule to an external validation cohort of 144 Caucasian patients with early dcSSc from the Royal Free Hospital cohort and compared stratum-specific 5-year mortality. RESULTS: Six independent predictors (rounded beta weight) comprised the model: age at first visit (points allotted: -1, 0, or 1), male sex (points allotted: 0 or 1), tendon friction rubs (points allotted: 0 or 1), gastrointestinal involvement (points allotted: 0 or 1), RNA polymerase III antibodies (points allotted: 0 or 1), and anemia (points allotted: 0 or 1). The 3-level risk stratification model performed well, with no significant differences between the US derivation cohort and the UK validation cohort. CONCLUSION: We derived and externally validated, in US and UK cohorts, an easy-to-use 6-variable prediction rule that assigns low-risk, moderate-risk, and high-risk categories for 5-year mortality in patients with early dcSSc. Only history, physical examination, and basic laboratory assessments are required

Study design and participant characteristics of a randomized controlled trial of directly administered antiretroviral therapy in opioid treatment programs

<p>Abstract</p> <p>Background</p> <p>HIV-infected drug users are at higher risk of non-adherence and poor treatment outcomes than HIV-infected non-drug users. Prior work from our group and others suggests that directly administered antiretroviral therapy (DAART) delivered in opioid treatment programs (OTPs) may increase rates of viral suppression.</p> <p>Methods/Design</p> <p>We are conducting a randomized trial comparing DAART to self-administered therapy (SAT) in 5 OTPs in Baltimore, Maryland. Participants and investigators are aware of treatment assignments. The DAART intervention is 12 months. The primary outcome is HIV RNA < 50 copies/mL at 3, 6, and 12 months. To assess persistence of any study arm differences that emerge during the active intervention, we are conducting an 18-month visit (6 months after the intervention concludes). We are collecting electronic adherence data for 2 months in both study arms. Of 457 individuals screened, a total of 107 participants were enrolled, with 56 and 51 randomly assigned to DAART and SAT, respectively. Participants were predominantly African American, approximately half were women, and the median age was 47 years. Active use of cocaine and other drugs was common at baseline. HIV disease stage was advanced in most participants. The median CD4 count at enrollment was 207 cells/mm³, 66 (62%) had a history of an AIDS-defining opportunistic condition, and 21 (20%) were antiretroviral naïve.</p> <p>Conclusions</p> <p>This paper describes the rationale, methods, and baseline characteristics of subjects enrolled in a randomized clinical trial comparing DAART to SAT in opioid treatment programs.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00279110">NCT00279110</a></p

Gene expression profiling of early intervertebral disc degeneration reveals a down-regulation of canonical Wnt signaling and caveolin-1 expression: implications for development of regenerative strategies

INTRODUCTION: Early degeneration of the intervertebral disc (IVD) involves a change in cellular differentiation from notochordal cells (NCs) in the nucleus pulposus (NP) to chondrocyte-like cells (CLCs). The purpose of this study was to investigate the gene expression profiles involved in this process using NP tissue from non-chondrodystrophic and chondrodystrophic dogs, a species with naturally occurring IVD degeneration. METHODS: Dual channel DNA microarrays were used to compare 1) healthy NP tissue containing only NCs (NC-rich), 2) NP tissue with a mixed population of NCs and CLCs (Mixed), and 3) NP tissue containing solely CLCs (CLC-rich) in both non-chondrodystrophic and chondrodystrophic dogs. Based on previous reports and the findings of the microarray analyses, canonical Wnt signaling was further evaluated using qPCR of relevant Wnt target genes. We hypothesized that caveolin-1, a regulator of Wnt signaling that showed significant changes in gene expression in the microarray analyses, played a significant role in early IVD degeneration. Caveolin-1 expression was investigated in IVD tissue sections and in cultured NCs. To investigate the significance of Caveolin-1 in IVD health and degeneration, the NP of 3-month-old Caveolin-1 knock-out mice was histopathologically evaluated and compared with the NP of wild-type mice of the same age. RESULTS: Early IVD degeneration involved significant changes in numerous pathways, including Wnt/β-catenin signaling. With regard to Wnt/β-catenin signaling, axin2 gene expression was significantly higher in chondrodystrophic dogs compared with non-chondrodystrophic dogs. IVD degeneration involved significant down-regulation of axin2 gene expression. IVD degeneration involved significant down-regulation in Caveolin-1 gene and protein expression. NCs showed abundant caveolin-1 expression in vivo and in vitro, whereas CLCs did not. The NP of wild-type mice was rich in viable NCs, whereas the NP of Caveolin-1 knock-out mice contained chondroid-like matrix with mainly apoptotic, small, rounded cells. CONCLUSIONS: Early IVD degeneration involves down-regulation of canonical Wnt signaling and Caveolin-1 expression, which appears to be essential to the physiology and preservation of NCs. Therefore, Caveolin-1 may be regarded an exciting target for developing strategies for IVD regeneration

Integrating transposable elements in the 3D genome

Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome