174 research outputs found

    Structure Property Correlation in Ultrafine Grained Copper Processed by Equal Channel Angular Processing

    Get PDF
    Ultra fine grained copper is produced by equal channel angular processing (ECAP) routes.Multiple passing through the ECAP die reveals high grain refinement in first few passes.Transmission electron microscopies in to the samples reveal a grain refinement of 150 μm to 500 nm sized grains after 4 passes. Mechanical properties measuerement shows that the severe plastic deformation has improved the structural strength to 410 MPa. Structure property study confirms the Hall petch strengthening mechanism operational during the deformation process. The effect of initial microstructral inhomogeniety is investigated and it is found to have marginal influence in the grain refinement of the multiple pass ECAP. Process modeling study using finite element models reveal the developed shear strain and stress fields during the deformtion process

    Psychosocial interventions for preventing and treating depression in dialysis patients

    Get PDF
    Background: People with end-stage kidney disease (ESKD) treated with dialysis are frequently affected by major depression. Dialysis patients have prioritised depression as a critically important clinical outcome in nephrology trials. Psychological and social support are potential treatments for depression, although a Cochrane review in 2005 identified zero eligible studies. This is an update of the Cochrane review first published in 2005. Objectives: To assess the effect of using psychosocial interventions versus usual care or a second psychosocial intervention for preventing and treating depression in patients with ESKD treated with dialysis. Search methods: We searched Cochrane Kidney and Transplant's Register of Studies up to 21 June 2019 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. Selection criteria: We included randomised controlled trials (RCTs) and quasi-RCTs of psychosocial interventions for prevention and treatment of depression among adults treated with long-term dialysis. We assessed effects of interventions on changes in mental state (depression, anxiety, cognition), suicide, health-related quality of life (HRQoL), withdrawal from dialysis treatment, withdrawal from intervention, death (any cause), hospitalisation and adverse events. Data collection and analysis: Two authors independently selected studies for inclusion and extracted study data. We applied the Cochrane 'Risk of Bias' tool and used the GRADE process to assess evidence certainty. We estimated treatment effects using random-effects meta-analysis. Results for continuous outcomes were expressed as a mean difference (MD) or as a standardised mean difference (SMD) when investigators used different scales. Dichotomous outcomes were expressed as risk ratios. All estimates were reported together with 95% confidence intervals (CI). Main results: We included 33 studies enrolling 2056 participants. Twenty-six new studies were added to this 2019 update. Seven studies originally excluded from the 2005 review were included as they met the updated review eligibility criteria, which have been expanded to include RCTs in which participants did not meet criteria for depression as an inclusion criterion. Psychosocial interventions included acupressure, cognitive-behavioural therapy, counselling, education, exercise, meditation, motivational interviewing, relaxation techniques, social activity, spiritual practices, support groups, telephone support, visualisation, and voice-recording of a psychological intervention. The duration of study follow-up ranged between three weeks and one year. Studies included between nine and 235 participants. The mean study age ranged between 36.1 and 73.9 years. Random sequence generation and allocation concealment were at low risk of bias in eight and one studies respectively. One study reported low risk methods for blinding of participants and investigators, and outcome assessment was blinded in seven studies. Twelve studies were at low risk of attrition bias, eight studies were at low risk of selective reporting bias, and 21 studies were at low risk of other potential sources of bias. Cognitive behavioural therapy probably improves depressive symptoms measured using the Beck Depression Inventory (4 studies, 230 participants: MD -6.10, 95% CI -8.63 to -3.57), based on moderate certainty evidence. Cognitive behavioural therapy compared to usual care probably improves HRQoL measured either with the Kidney Disease Quality of Life Instrument Short Form or the Quality of Life Scale, with a 0.5 standardised mean difference representing a moderate effect size (4 studies, 230 participants: SMD 0.51, 95% CI 0.19 to 0.83), based on moderate certainty evidence. Cognitive behavioural therapy may reduce major depression symptoms (one study) and anxiety, and increase self-efficacy (one study). Cognitive behavioural therapy studies did not report hospitalisation. We found low-certainty evidence that counselling may slightly reduce depressive symptoms measured with the Beck Depression Inventory (3 studies, 99 participants: MD -3.84, 95% CI -6.14 to -1.53) compared to usual care. Counselling reported no difference in HRQoL (one study). Counselling studies did not measure risk of major depression, suicide, or hospitalisation. Exercise may reduce or prevent major depression (3 studies, 108 participants: RR 0.47, 95% CI 0.27 to 0.81), depression of any severity (3 studies, 108 participants: RR 0.69, 95% CI 0.54 to 0.87) and improve HRQoL measured with Quality of Life Index score (2 studies, 64 participants: MD 3.06, 95% CI 2.29 to 3.83) compared to usual care with low certainty. With moderate certainty, exercise probably improves depression symptoms measured with the Beck Depression Inventory (3 studies, 108 participants: MD -7.61, 95% CI -9.59 to -5.63). Exercise may reduce anxiety (one study). No exercise studies measured suicide risk or withdrawal from dialysis. We found moderate-certainty evidence that relaxation techniques probably reduce depressive symptoms measured with the Beck Depression Inventory (2 studies, 122 participants: MD -5.77, 95% CI -8.76 to -2.78). Relaxation techniques reported no difference in HRQoL (one study). Relaxation studies did not measure risk of major depression or suicide. Spiritual practices have uncertain effects on depressive symptoms measured either with the Beck Depression Inventory or the Brief Symptom Inventory (2 studies, 116 participants: SMD -1.00, 95% CI -3.52 to 1.53; very low certainty evidence). No differences between spiritual practices and usual care were reported on anxiety (one study), and HRQoL (one study). No study of spiritual practices evaluated effects on suicide risk, withdrawal from dialysis or hospitalisation. There were few or no data on acupressure, telephone support, meditation and adverse events related to psychosocial interventions. Authors' conclusions: Cognitive behavioural therapy, exercise or relaxation techniques probably reduce depressive symptoms (moderate-certainty evidence) for adults with ESKD treated with dialysis. Cognitive behavioural therapy probably increases health-related quality of life. Evidence for spiritual practices, acupressure, telephone support, and meditation is of low certainty. Similarly, evidence for effects of psychosocial interventions on suicide risk, major depression, hospitalisation, withdrawal from dialysis, and adverse events is of low or very low certainty

    Endoscopy simulation for pre-clerkship students

    Get PDF
    Implication: Here we report a simulation session carried out with pre-clerkship medical students during their gastroenterology block.  We used endoscopy simulator to cement the clinical and anatomic implications of endoscopy and to build interest in gastroenterology. Students thought the session was helpful for their interest and understanding. Endoscopy simulation provided for pre-clinical students could help to bolster high-level understanding of gastroenterology as well as understanding of clinical and procedural aspects of the specialty

    Stepwise reduction of electron-precise, six-electron, triangular, [Mo<SUB>3</SUB><SUP>IV</SUP>S<SUB>4</SUB>(CN)<SUB>9</SUB>]<SUP>5-</SUP> to electron-rich seven, eight and unstable nine-electron species resulting in core expansion to electron-precise, twelvee-lectron, tetrahedral, [Mo<SUB>4</SUB><SUP>III</SUP>S<SUB>4</SUB>(CN)<SUB>12</SUB>]<SUP>8-</SUP>

    Get PDF
    Facile reduction of the triangular {Mo3IV }6-core containing [Mo3S4 (CN)9]5- derivative is achieved in aqueous medium, containing the KOH-KCN-K2 [Zn(CN)4] ternary system as supporting electrolyte, in a two-step one-electron reduction reaction followed by an irreversible one. The diamagnetic species containing the {Mo3}8 core, obtained by chemical reduction of [Mo3S4(CN)9]5- with zinc in aqueous medium containing KOH-KCN, is oxidized by air in two steps. The partially oxidized species with {Mo3}7 core in the first step exhibits characteristic ESR signals which on further oxidation quantitatively reverts to the original compound with {Mo3}6 core displaying distinctly separate isosbestic points in the stepwise conversion of {Mo3}8 to {Mo3}7 and {Mo3}7 to {Mo3}6 cores. Under drastic reduction conditions with aluminium in 40% aqueous KOH solution the {Mo3}6 core is reduced to unstable trinuclear {Mo3III }9 core which expands to tetrahedral {Mo4III }12-core containing [Mo4S4(CN)12]8- derivative according to electron-precise cluster rule

    Uteroglobin Represses Allergen-induced Inflammatory Response by Blocking PGD2 Receptor–mediated Functions

    Get PDF
    Uteroglobin (UG) is an antiinflammatory protein secreted by the epithelial lining of all organs communicating with the external environment. We reported previously that UG-knockout mice manifest exaggerated inflammatory response to allergen, characterized by increased eotaxin and Th2 cytokine gene expression, and eosinophil infiltration in the lungs. In this study, we uncovered that the airway epithelia of these mice also express high levels of cyclooxygenase (COX)-2, a key enzyme for the production of proinflammatory lipid mediators, and the bronchoalveolar lavage fluid (BALF) contain elevated levels of prostaglandin D2. These effects are abrogated by recombinant UG treatment. Although it has been reported that prostaglandin D2 mediates allergic inflammation via its receptor, DP, neither the molecular mechanism(s) of DP signaling nor the mechanism by which UG suppresses DP-mediated inflammatory response are clearly understood. Here we report that DP signaling is mediated via p38 mitogen–activated protein kinase, p44/42 mitogen–activated protein kinase, and protein kinase C pathways in a cell type–specific manner leading to nuclear factor–κB activation stimulating COX-2 gene expression. Further, we found that recombinant UG blocks DP-mediated nuclear factor–κB activation and suppresses COX-2 gene expression. We propose that UG is an essential component of a novel innate homeostatic mechanism in the mammalian airways to repress allergen-induced inflammatory responses

    Highly tunable magnetic spirals and electric polarization in Gd0.5Dy0.5MnO3

    Get PDF
    Recent progress in the field of multiferroics led to the discovery of many new materials in which ferroelectricity is induced by cycloidal spiral orders. The direction of the electric polarization is typically constrained by spin anisotropies and magnetic field. Here, we report that the mixed rare-earth manganite, Gd0.5Dy0.5MnO3, exhibits a spontaneous electric polarization along a general direction in the crystallographic ac plane, which is suppressed below 10 K but reemerges in an applied magnetic field. Neutron-diffraction measurements show that the polarization direction results from a large tilt of the spiral plane with respect to the crystallographic axes and that the suppression of ferroelectricity is caused by the transformation of a cycloidal spiral into a helical one, a unique property of this rare-earth manganite. The freedom in the orientation of the spiral plane allows for a fine magnetic control of ferroelectricity, i.e., a rotation as well as a strong enhancement of the polarization depending on the magnetic-field direction. We show that this unusual behavior originates from the coupling between the transition-metal and rare-earth magnetic subsystems

    Systematic review of the effectiveness of preventing and treating Staphylococcus aureus carriage in reducing peritoneal catheter-related infections

    Get PDF
    Objectives: To determine the clinical effectiveness and cost-effectiveness of (1) alternative strategies for the prevention of Staphylococcus aureus carriage in patients on peritoneal dialysis (PD) and (2) alternative strategies for the eradication of S. aureus carriage in patients on PD. Data sources: Major electronic databases were searched up to December 2005 (MEDLINE Extra up to 6 January 2006). Review methods: Electronic searches were undertaken to identify published and unpublished reports of randomised controlled trials and systematic reviews evaluating the effectiveness of preventing and treating S. aureus carriage on peritoneal catheterrelated infections. The quality of the included studies was assessed and data synthesised. Where data were not sufficient for formal meta-analysis, a qualitative narrative review looking for consistency between studies was performed. Results: Twenty-two relevant trials were found. These fell into several groups: the first split is between prophylactic trials, aiming to prevent carriage, and trials which aimed to eradicate carriage in those who already had it; the second split is between antiseptics and antibiotics; and the third split is between those that included patients having the catheter inserted before dialysis started and people already on dialysis. Many of the trials were small or short-term. The quality was often not good by today’s standards. The body of evidence suggested a reduction in exit-site infections, but this did not seem to lead to a significant reduction in peritonitis, although to some extent this reflected insufficient power in the studies and a low incidence of peritonitis in them. The costs of interventions to prevent or treat S. aureus carriage are relatively modest. For example, the annual cost of antibiotic treatment of S. aureus carriage per identified carrier of S. aureus was estimated at £179 (£73 screening and £106 cost of antibiotic). However, without better data on the effectiveness of the interventions, it is not clear whether such costs are offset by the cost of treating infections and averting changes from peritoneal dialysis to haemodialysis. Although treatment is not expensive, the lack of convincing evidence of clinical effectiveness made cost-effectiveness analysis unrewarding at present. However, consideration was given to the factors needed in a hypothetical model describing patient pathways from methods to prevent S. aureus carriage, its detection and treatment and the detection and treatment of the consequences of S. aureus (e.g. catheter infections and peritonitis). Had data been available, the model would have compared the costeffectiveness of alternative interventions from the perspective of the UK NHS, but as such it helped identify what future research would be needed to fill the gaps. Conclusions: The importance of peritonitis isnot in doubt. It is the main cause of people having to switch from peritoneal dialysis to haemodialysis, which then leads to reduced quality of life for patients and increased costs to the NHS. Unfortunately, the present evidence base for the prevention of peritonitis is disappointing; it suggests that the interventions reduce exit-site infections, but not peritonitis, although this may be due to trials being in too small numbers for too short periods. Trials are needed with larger numbers of patients for longer durations.No peer reviewPublisher PD

    The clinical effectiveness and cost-effectiveness of screening for open angle glaucoma : a systematic review and economic evaluation

    Get PDF
    Objectives: To assess whether open angle glaucoma (OAG) screening meets the UK National Screening Committee criteria, to compare screening strategies with case finding, to estimate test parameters, to model estimates of cost and cost-effectiveness, and to identify areas for future research. Data sources: Major electronic databases were searched up to December 2005. Review methods: Screening strategies were developed by wide consultation. Markov submodels were developed to represent screening strategies. Parameter estimates were determined by systematic reviews of epidemiology, economic evaluations of screening, and effectiveness (test accuracy, screening and treatment). Tailored highly sensitive electronic searches were undertaken. Results: Most potential screening tests reviewed had an estimated specificity of 85% or higher. No test was clearly most accurate, with only a few, heterogeneous studies for each test. No randomised controlled trials (RCTs) of screening were identified. Based on two treatment RCTs, early treatment reduces the risk of progression. Extrapolating from this, and assuming accelerated progression with advancing disease severity, without treatment the mean time to blindness in at least one eye was approximately 23 years, compared to 35 years with treatment. Prevalence would have to be about 3–4% in 40 year olds with a screening interval of 10 years to approach costeffectiveness. It is predicted that screening might be cost-effective in a 50-year-old cohort at a prevalence of 4% with a 10-year screening interval. General population screening at any age, thus, appears not to be cost-effective. Selective screening of groups with higher prevalence (family history, black ethnicity) might be worthwhile, although this would only cover 6% of the population. Extension to include other at-risk cohorts (e.g. myopia and diabetes) would include 37% of the general population, but the prevalence is then too low for screening to be considered cost-effective. Screening using a test with initial automated classification followed by assessment by a specialised optometrist, for test positives, was more cost-effective than initial specialised optometric assessment. The cost-effectiveness of the screening programme was highly sensitive to the perspective on costs (NHS or societal). In the base-case model, the NHS costs of visual impairment were estimated as £669. If annual societal costs were £8800, then screening might be considered cost-effective for a 40-year-old cohort with 1% OAG prevalence assuming a willingness to pay of £30,000 per quality-adjusted life-year. Of lesser importance were changes to estimates of attendance for sight tests, incidence of OAG, rate of progression and utility values for each stage of OAG severity. Cost-effectiveness was not particularly sensitive to the accuracy of screening tests within the ranges observed. However, a highly specific test is required to reduce large numbers of false-positive referrals. The findings that population screening is unlikely to be cost-effective are based on an economic model whose parameter estimates have considerable uncertainty. In particular, if rate of progression and/or costs of visual impairment are higher than estimated then screening could be cost-effective. Conclusions: While population screening is not costeffective, the targeted screening of high-risk groups may be. Procedures for identifying those at risk, for quality assuring the programme, as well as adequate service provision for those screened positive would all be needed. Glaucoma detection can be improved by increasing attendance for eye examination, and improving the performance of current testing by either refining practice or adding in a technology-based first assessment, the latter being the more cost-effective option. This has implications for any future organisational changes in community eye-care services. Further research should aim to develop and provide quality data to populate the economic model, by conducting a feasibility study of interventions to improve detection, by obtaining further data on costs of blindness, risk of progression and health outcomes, and by conducting an RCT of interventions to improve the uptake of glaucoma testing.Peer reviewedPublisher PD
    corecore