3,353 research outputs found

    Multiplicative random walk Metropolis-Hastings on the real line

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    In this article we propose multiplication based random walk Metropolis Hastings (MH) algorithm on the real line. We call it the random dive MH (RDMH) algorithm. This algorithm, even if simple to apply, was not studied earlier in Markov chain Monte Carlo literature. The associated kernel is shown to have standard properties like irreducibility, aperiodicity and Harris recurrence under some mild assumptions. These ensure basic convergence (ergodicity) of the kernel. Further the kernel is shown to be geometric ergodic for a large class of target densities on R\mathbb{R}. This class even contains realistic target densities for which random walk or Langevin MH are not geometrically ergodic. Three simulation studies are given to demonstrate the mixing property and superiority of RDMH to standard MH algorithms on real line. A share-price return data is also analyzed and the results are compared with those available in the literature

    Droplet-based electro-coalescence for probing threshold disjoining pressure

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    In this work, we investigate the coalescence of emulsion droplets in a controlled electric field. Two contacting droplets stabilized by surfactants can be forced to coalesce into a combined one when the applied voltage is above a critical value. The critical voltages change with the types, concentrations of surfactants and temperature. By exploring the drainage of a thin oil film trapped between emulsions, we interpret that the coalescence occurs as the electric compression overcomes the disjoining pressure barrier and squeezes the film to a critical thickness. Based on this, we have devised an approach to probe the threshold disjoining pressure which can help predict the emulsion stability and surfactant efficacy quantitatively. We have confirmed the validity of our approach for measuring the threshold disjoining pressure by comparing the result with other proven tests that involve centrifugation and thermal heating. Our approach is simple, reliable and robust in predicting emulsion stability and will facilitate the design of emulsion-based formulations by accelerating the testing of emulsion stability.postprin

    A machine learning‑based image segmentation method to quantify in vitro osteoclast culture endpoints

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    Quantification of in vitro osteoclast cultures (e.g. cell number) often relies on manual counting methods. These approaches are labour intensive, time consuming and result in substantial inter- and intra-user variability. This study aimed to develop and validate an automated workflow to robustly quantify in vitro osteoclast cultures. Using ilastik, a machine learning-based image analysis software, images of tartrate resistant acid phosphatase-stained mouse osteoclasts cultured on dentine discs were used to train the ilastik-based algorithm. Assessment of algorithm training showed that osteoclast numbers strongly correlated between manual- and automatically quantified values (r = 0.87). Osteoclasts were consistently faithfully segmented by the model when visually compared to the original reflective light images. The ability of this method to detect changes in osteoclast number in response to different treatments was validated using zoledronate, ticagrelor, and co-culture with MCF7 breast cancer cells. Manual and automated counting methods detected a 70% reduction (p < 0.05) in osteoclast number, when cultured with 10 nM zoledronate and a dose-dependent decrease with 1-10 μM ticagrelor (p < 0.05). Co-culture with MCF7 cells increased osteoclast number by ≥ 50% irrespective of quantification method. Overall, an automated image segmentation and analysis workflow, which consistently and sensitively identified in vitro osteoclasts, was developed. Advantages of this workflow are (1) significantly reduction in user variability of endpoint measurements (93%) and analysis time (80%); (2) detection of osteoclasts cultured on different substrates from different species; and (3) easy to use and freely available to use along with tutorial resources

    Analysis of a Clostridium difficile PCR ribotype 078 100 kilobase island reveals the presence of a novel transposon, Tn6164.

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    Clostridium difficile is the main cause of antibiotic associated diarrhea. In the past decade, the number of C. difficile patients has increased dramatically, coinciding with the emergence of two PCR ribotypes 027 and 078. PCR ribotype 078 is also frequently found during C. difficile outbreaks in pigfarms. Previously, the genome of the PCR ribotype 078 strain M120, a human isolate, was described to contain a unique insert of 100 kilobases

    The 14q32 maternally imprinted locus is a major source of longitudinally stable circulating microRNAs as measured by small RNA sequencing

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    Understanding the normal temporal variation of serum molecules is a critical factor for identifying useful candidate biomarkers for the diagnosis and prognosis of chronic disease. Using small RNA sequencing in a longitudinal study of 66 women with no history of cancer, we determined the distribution and dynamics (via intraclass correlation coefficients, ICCs) of the miRNA profile over 3 time points sampled across 2–5 years in the course of the screening trial, UKCTOCS. We were able to define a subset of longitudinally stable miRNAs (ICC >0.75) that were individually discriminating of women who had no cancer over the study period. These miRNAs were dominated by those originating from the C14MC cluster that is subject to maternal imprinting. This assessment was not significantly affected by common confounders such as age, BMI or time to centrifugation nor alternative methods to data normalisation. Our analysis provides important benchmark data supporting the development of miRNA biomarkers for the impact of life-course exposure as well as diagnosis and prognostication of chronic disease

    ARTISTIC: A randomised trial of human papillomavirus (HPV) testing in primary cervical screening

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    The official published version of the article can be found at the link below.Objectives: Primary cervical screening uses cytology to detect cancer precursor lesions [cervical intraepithelial neoplasia stage 3 or beyond (CIN3+)]. Human papillomavirus (HPV) testing could add sensitivity as an adjunct to cytology or as a first test, reserving cytology for HPV-positive women. This study addresses the questions: Does the combination of cytology and HPV testing achieve a reduction in incident CIN3+?; Is HPV testing cost-effective in primary cervical screening?; Is its use associated with adverse psychosocial or psychosexual effects?; and How would it perform as an initial screening test followed by cytology for HPV positivity? Design: ARTISTIC was a randomised trial of cervical cytology versus cervical cytology plus HPV testing, evaluated over two screening rounds, 3 years apart. Round 1 would detect prevalent disease and round 2 a combination of incident and undetected disease from round 1. Setting: Women undergoing routine cervical screening in the NHS programme in Greater Manchester. Participants: In total 24,510 women aged 20–64 years were enrolled between July 2001 and September 2003. Interventions: HPV testing was performed on the liquid-based cytology (LBC) sample obtained at screening. Women were randomised in a ratio of 3:1 to have the HPV test result revealed and acted upon if persistently positive in cytology-negative cases or concealed. A detailed health economic evaluation and a psychosocial and psychosexual assessment were also performed. Main outcome measures: The primary outcome was CIN3+ in round 2. Secondary outcomes included an economic assessment and psychosocial effects. A large HPV genotyping study was also conducted. Results: In round 1 there were 313 CIN3+ lesions, representing a prevalence in the revealed and concealed arms of 1.27% and 1.31% respectively (p = 0.81). Round 2 (30–48 months) involved 14,230 (58.1%) of the women screened in round 1 and only 31 CIN3+ were detected; the CIN3 rate was not significantly different between the revealed and concealed arms. A less restrictive definition of round 2 (26–54 months) increased CIN3+ to 45 and CIN3+ incidence in the arms was significantly different (p = 0.05). There was no difference in CIN3+ between the arms when rounds 1 and 2 were combined. Prevalence of highrisk HPV types was age-dependent. Overall prevalence of HPV16/18 increased with severity of yskaryosis. Mean costs per woman in round 1 were £72 and £56 for the revealed and concealed arms (p < 0.001); an age-adjustment reduced these mean costs to £65 and £52. Incremental cost-effectiveness ratio for detecting additional CIN3+ by adding HPV testing to LBC screening in round 1 was £38,771. Age-adjusted mean cost for LBC primary screening with HPV triage was £39 compared with £48 for HPV primary screening with LBC triage. HPV testing did not appear to cause significant psychosocial distress. Conclusions: Routine HPV testing did not add significantly to the effectiveness of LBC in this study. No significant adverse psychosocial effects were detected. It would not be cost-effective to screen with cytology and HPV combined but HPV testing, as either triage or initial test triaged by cytology, would be cheaper than cytology without HPV testing. LBC would not benefit from combination with HPV; it is highly effective as primary screening but HPV testing has twin advantages of high negative predictive value and automated platforms enabling high throughput. HPV primary screening would require major contraction and reconfiguration of laboratory services. Follow-up continues in ARTISTIC while maintaining concealment for a further 3-year round of screening, which will help in screening protocol development for the post-vaccination era

    A programme evaluation of \u27First Steps\u27: A peer-conceived, developed and led self-management intervention for people after a Parkinson\u27s diagnosis

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    \ua9 The Author(s) 2023. Objective: A diagnosis of Parkinson\u27s often leads to uncertainty about the future and loss of perceived control. Peer support may offer a means to address these concerns and promote self-management. Design: A programme evaluation of the feasibility and potential effects of ‘First Steps’, utilising a pragmatic step wedge approach. Comparing First Steps (intervention) to (control) conditions. Setting: In the community at four sites in southern England. Participants: Newly diagnosed (≤ 12months) people with Parkinson\u27s. Intervention: First Steps was a 2-day peer-conceived, developed and led intervention to support self-management. Main measures: At 0, 12 and 24 weeks anxiety and depression (Hospital, Anxiety and Depression Scale, HADS), daily functioning (World Health Organisation Disability Assessment Schedule, WHODAS), physical activity, quality of life (EQ5D), carer strain and service utilisation were assessed. Results: Between February 2018 and July 2019, 36 participants were enrolled into intervention and 21 to control conditions, all were included in statistical analysis. Lost to follow up was n = 1 (intervention) and n = 1 adverse event was reported (control, unrelated). Of the 36 allocated to the intervention n = 22 participants completed both days of First Steps during the study period. Completion of outcome measures was &gt;95% at 24 weeks. Small effects favouring the intervention were found for HADS (odds ratio (OR) = 2.06, 95% confidence interval (CI) 0.24:17.84), Carer Strain Index (OR = 2.22, 95% CI 0.5:9.76) and vigorous (d = 0.42, 95% CI −0.12:0.97) and total physical activity (d = 0.41, 95% CI −0.13:0.95). EQ5D, WHOSDAS and service utilisation, was similar between groups. Conclusions: First Steps was feasible and safe and we found potential to benefit physical activity, mental health and carer strain. Further research with longer-term follow up is warranted

    Safety and efficacy of fluticasone propionate in the topical treatment of skin diseases

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    Fluticasone propionate - the first carbothioate corticosteroid - has been classified as a potent anti-inflammatory drug for dermatological use. It is available as 0.05% cream and 0.005% ointment formulations for the acute and maintenance treatment of patients with dermatological disorders such as atopic dermatitis, psoriasis and vitiligo. This glucocorticoid is characterized by high lipophilicity, high glucocorticoid receptor binding and activation, and a rapid metabolic turnover in skin. Although skin blanching following fluticasone propionate exceeds that of corticosteroids of medium strength, several clinical trials demonstrate a low potential for cutaneous and systemic side-effects, even in difficult-to-treat areas like the face, the eyelids and intertriginous areas. Even among paediatric patients with atopic dermatitis, fluticasone propionate proved to be safe and effective. These pharmacological and clinical properties are reflected by the high therapeutic index of this glucocorticoid
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