192 research outputs found

    Modeling the effect of packing density on filtration performances in hollow fiber microfiltration module: a spatial study of cake growth

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    This study continues from a previous work on the impact of packing density on the fluid flow distribution in a hollow fiber module [1]. A numerical model was developed to simulate the growth of a particle cake along the surface of a hollow fiber membrane and the subsequent fluid flow during a microfiltration operation. The model accounts for the continuous change in porous domain (cake and porous wall) geometry and permeability as long as filtration occurs. The effect module packing density has upon cake growth is carefully analyzed both for inside/out (I/O) and outside/in (O/I) filtration modes. The results exhibit significant differences in the time variations of cake spatial distribution along the fiber as a function of packing density for both filtration modes. Then a confrontation between forward filtration and backward filtration velocities offers some conclusion on the effect of packing density on the backwash efficiency. This in turn underlines the importance of design parameters in the filtration performance of a hollow fiber module

    A novel high-throughput screen for identifying lipids that stabilise membrane proteins in detergent based solution

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    Membrane proteins have a range of crucial biological functions and are the target of about 60% of all prescribed drugs. For most studies, they need to be extracted out of the lipid-bilayer, e.g. by detergent solubilisation, leading to the loss of native lipids, which may disturb important protein-lipid/bilayer interactions and thus functional and structural integrity. Relipidation of membrane proteins has proven extremely successful for studying challenging targets, but the identification of suitable lipids can be expensive and laborious. Therefore, we developed a screen to aid the high-throughput identification of beneficial lipids. The screen covers a large lipid space and was designed to be suitable for a range of stability assessment methods. Here, we demonstrate its use as a tool for identifying stabilising lipids for three membrane proteins: a bacterial pyrophosphatase (Tm-PPase), a fungal purine transporter (UapA) and a human GPCR (A(2A)R). A(2A)R is stabilised by cholesteryl hemisuccinate, a lipid well known to stabilise GPCRs, validating the approach. Additionally, our screen also identified a range of new lipids which stabilised our test proteins, providing a starting point for further investigation and demonstrating its value as a novel tool for membrane protein research. The pre-dispensed screen will be made commercially available to the scientific community in future and has a number of potential applications in the field.Peer reviewe

    A combined geomorphological and geophysical approach to characterising relict landslide hazard on the Jurassic Escarpments of Great Britain

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    The Jurassic Escarpment in the North York Moors in Northern Britain has a high density of deep-seated relict landslides but their regional hazard is poorly understood due to a lack of detailed case studies. Investigation of a typical relict landslide at Great Fryup Dale suggests that the crop of the Whitby Mudstone Formation is highly susceptible to landslide hazards. The mudstone lithologies along the Escarpment form large multiple rotational failures which break down at an accelerated rate during wetter climates and degrade into extensive frontal mudflows. Geomorphological mapping, high resolution LiDAR imagery, boreholes, and geophysical ERT surveys are deployed in a combined approach to delimit internal architecture of the landslide. Cross-sections developed from these data indicate that the main movement displaced a bedrock volume of c. 1 × 107 m3 with a maximum depth of rupture of c. 50 m. The mode of failure is strongly controlled by lithology, bedding, joint pattern, and rate of lateral unloading. Dating of buried peats using the AMS method suggests that the 10 m thick frontal mudflow complex was last active in the Late Holocene, after c. 2270 ± 30 calendar years BP. Geomorphic mapping and dating work indicates that the landslide is dormant, but slope stability modelling suggests that the slope is less stable than previously assumed; implying that this and other similar landslides in Britain may become more susceptible to reactivation or extension during future wetter climatic phases. This study shows the value of a multi-technique approach for landslide hazard assessment and to enhance national landslide inventories

    How different data sources and definitions of neighbourhood influence the association between food outlet availability and body mass index: a cross-sectional study.

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    Inconsistencies in methodologies continue to inhibit understanding of the impact of the environment on body mass index (BMI). To estimate the effect of these differences, we assessed the impact of using different definitions of neighbourhood and data sets on associations between food outlet availability within the environment and BMI. Previous research has not extended this to show any differences in the strength of associations between food outlet availability and BMI across both different definitions of neighbourhood and data sets. Descriptive statistics showed differences in the number of food outlets, particularly other food retail outlets between different data sets and definitions of neighbourhood. Despite these differences, our key finding was that across both different definitions of neighbourhood and data sets, there was very little difference in size of associations between food outlets and BMI. Researchers should consider and transparently report the impact of methodological choices such as the definition of neighbourhood and acknowledge any differences in associations between the food environment and BMI

    Cost-effectiveness of self-management of blood pressure in hypertensive patients over 70 years with suboptimal control and established cardiovascular disease or additional cardiovascular risk diseases (TASMIN-SR).

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    BACKGROUND: A previous economic analysis of self-management, that is, self-monitoring with self-titration of antihypertensive medication evaluated cost-effectiveness among patients with uncomplicated hypertension. This study considered cost-effectiveness of self-management in those with raised blood pressure plus diabetes, chronic kidney disease and/or previous cardiovascular disease. DESIGN AND METHODS: A Markov model-based economic evaluation was undertaken to estimate the long-term cost-effectiveness of self-management of blood pressure in a cohort of 70-year-old 'high risk' patients, compared with usual care. The model used the results of the TASMIN-SR trial. A cost-utility analysis was undertaken from a UK health and social care perspective, taking into account lifetime costs of treatment, cardiovascular events and quality adjusted life years. A subgroup analysis ran the model separately for men and women. Deterministic sensitivity analyses examined the effect of different time horizons and reduced effectiveness of self-management. RESULTS: Base-case results indicated that self-management was cost-effective compared with usual care, resulting in more quality adjusted life years (0.21) and cost savings (-ÂŁ830) per patient. There was a 99% chance of the intervention being cost-effective at a willingness to pay threshold of ÂŁ20,000 per quality adjusted life year gained. Similar results were found for separate cohorts of men and women. The results were robust to sensitivity analyses, provided that the blood pressure lowering effect of self-management was maintained for more than a year. CONCLUSION: Self-management of blood pressure in high-risk people with poorly controlled hypertension not only reduces blood pressure, compared with usual care, but also represents a cost-effective use of healthcare resources.This paper presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research Programme (Grant Reference Number RP-PG 0606-1153) and by the NIHR National School of Primary Care Research (NSPCR 16). The views expressed in this paper are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Service support costs were administered through the Primary Care Research Network and collaborating Comprehensive Local Research Networks. Prof McManus was supported by NIHR Career Development and Professional Fellowships, Professors Hobbs, Little and Williams are NIHR senior investigators. Professor McManus and Hobbs receive support from the NIHR CLAHRC Oxford. Professor Hobbs also receives support from the NIHR School for Primary Care Research and the NIHR Oxford BRC.This is the final version of the article. It first appeared from SAGE via https://doi.org/10.1177/204748731561878

    The effect of pre-exercise alkalosis on lactate/pH regulation and mitochondrial respiration following sprint-interval exercise in humans

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    Purpose: The purpose of this study was to evaluate the effect of pre-exercise alkalosis, induced via ingestion of sodium bicarbonate, on changes to lactate/pH regulatory proteins and mitochondrial function induced by a sprint-interval exercise session in humans. Methods: On two occasions separated by 1 week, eight active men performed a 3 × 30-s all-out cycling test, interspersed with 20 min of recovery, following either placebo (PLA) or sodium bicarbonate (BIC) ingestion. Results: Blood bicarbonate and pH were elevated at all time points after ingestion in BIC vs PLA (p < 0.05). The protein content of monocarboxylate transporter 1 (MCT1) and basigin (CD147), at 6 h and 24 h post-exercise, and sodium/hydrogen exchanger 1 (NHE1) 24 h post-exercise, were significantly greater in BIC compared to PLA (p < 0.05), whereas monocarboxylate transporter 4 (MCT4), sodium/bicarbonate cotransporter (NBC), and carbonic anhydrase isoform II (CAII) content was unchanged. These increases in protein content in BIC vs. PLA after acute sprint-interval exercise may be associated with altered physiological responses to exercise, such as the higher blood pH and bicarbonate concentration values, and lower exercise-induced oxidative stress observed during recovery (p < 0.05). Additionally, mitochondrial respiration decreased after 24 h of recovery in the BIC condition only, with no changes in oxidative protein content in either condition. Conclusion: These data demonstrate that metabolic alkalosis induces post-exercise increases in several lactate/pH regulatory proteins, and reveal an unexpected role for acidosis in mitigating the loss of mitochondrial respiration caused by exercise in the short term

    Effect of Self-monitoring and Medication Self-titration on Systolic Blood Pressure in Hypertensive Patients at High Risk of Cardiovascular Disease

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    IMPORTANCE: Self-monitoring of blood pressure with self-titration of antihypertensives (self-management) results in lower blood pressure in patients with hypertension, but there are no data about patients in high-risk groups. OBJECTIVE: To determine the effect of self-monitoring with self-titration of antihypertensive medication compared with usual care on systolic blood pressure among patients with cardiovascular disease, diabetes, or chronic kidney disease. DESIGN, SETTING, AND PATIENTS: A primary care, unblinded, randomized clinical trial involving 552 patients who were aged at least 35 years with a history of stroke, coronary heart disease, diabetes, or chronic kidney disease and with baseline blood pressure of at least 130/80 mm Hg being treated at 59 UK primary care practices was conducted between March 2011 and January 2013. INTERVENTIONS: Self-monitoring of blood pressure combined with an individualized self-titration algorithm. During the study period, the office visit blood pressure measurement target was 130/80 mm Hg and the home measurement target was 120/75 mm Hg. Control patients received usual care consisting of seeing their health care clinician for routine blood pressure measurement and adjustment of medication if necessary. MAIN OUTCOMES AND MEASURES: The primary outcome was the difference in systolic blood pressure between intervention and control groups at the 12-month office visit. RESULTS: Primary outcome data were available from 450 patients (81%). The mean baseline blood pressure was 143.1/80.5 mm Hg in the intervention group and 143.6/79.5 mm Hg in the control group. After 12 months, the mean blood pressure had decreased to 128.2/73.8 mm Hg in the intervention group and to 137.8/76.3 mm Hg in the control group, a difference of 9.2 mm Hg (95% CI, 5.7-12.7) in systolic and 3.4 mm Hg (95% CI, 1.8-5.0) in diastolic blood pressure following correction for baseline blood pressure. Multiple imputation for missing values gave similar results: the mean baseline was 143.5/80.2 mm Hg in the intervention group vs 144.2/79.9 mm Hg in the control group, and at 12 months, the mean was 128.6/73.6 mm Hg in the intervention group vs 138.2/76.4 mm Hg in the control group, with a difference of 8.8 mm Hg (95% CI, 4.9-12.7) for systolic and 3.1 mm Hg (95% CI, 0.7-5.5) for diastolic blood pressure between groups. These results were comparable in all subgroups, without excessive adverse events. CONCLUSIONS AND RELEVANCE: Among patients with hypertension at high risk of cardiovascular disease, self-monitoring with self-titration of antihypertensive medication compared with usual care resulted in lower systolic blood pressure at 12 months

    Development of a pathway to facilitate gastrostomy insertion for patients with MND

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    A pathway has been developed using a multidisciplinary group from within specialist palliative care to ensure a comprehensive approach to the insertion of gastromy tubes for patients with motor neurone disease (MND) with swallowing difficulties. The pathway has ensured that there is a coordinated approach and the professionals involved are clear as to their responsibilities in the discussion and planning of the insertion, ensuring the best support for the patient and family

    Telemonitoring and/or self-monitoring of blood pressure in hypertension (TASMINH4): protocol for a randomised controlled trial.

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    BACKGROUND: Self-monitoring of hypertension is associated with lower systolic blood pressure (SBP). However, evidence for the use of self-monitoring to titrate antihypertensive medication by physicians is equivocal. Furthermore, there is some evidence for the efficacy of telemonitoring in the management of hypertension but it is not clear what this adds over and above self-monitoring. This trial aims to evaluate whether GP led antihypertensive titration using self-monitoring results in lower SBP compared to usual care and whether telemonitoring adds anything to self-monitoring alone. METHODS/DESIGN: This will be a pragmatic primary care based, unblinded, randomised controlled trial of self-monitoring of BP with or without telemonitoring compared to usual care. Eligible patients will have poorly controlled hypertension (>140/90 mmHg) and will be recruited from primary care. Participants will be individually randomised to either usual care, self-monitoring alone, or self-monitoring with telemonitoring. The primary outcome of the trial will be difference in clinic SBP between intervention and control groups at 12 months adjusted for baseline SBP, gender, BP target and practice. At least 1110 patients will be sufficient to detect a difference in SBP between self-monitoring with or without telemonitoring and usual care of 5 mmHg with 90% power with an adjusted alpha of 0.017 (2-sided) to adjust for all three pairwise comparisons. Other outcomes will include adherence of anti-hypertensive medication, lifestyle behaviours, health-related quality of life, and adverse events. An economic analysis will consider both within trial costs and a model extrapolating the results thereafter. A qualitative sub study will gain insights into the views, experiences and decision making processes of patients and health care professionals focusing on the acceptability of self-monitoring and telemonitoring in the routine management of hypertension. DISCUSSION: The results of the trial will be directly applicable to primary care in the UK. If successful, self-monitoring of BP in people with hypertension would be applicable to hundreds of thousands of individuals in the UK. TRIAL REGISTRATION: ISRCTN 83571366 . Registered 17 July 2014.The trial is funded by an NIHR Programme grant, and by an NIHR Professorship awarded to Prof RJ McManus, the Chief Investigator. Omron have provided the blood pressure self-monitoring equipment via an unrestricted grant. Service support costs are administered through the NIHR Clinical Research Network: West Midlands. Professors Hobbs and Professor ï»żFarmer are NIHR Senior Investigators. This article presents independent research commissioned by the National Institute for Health Research (NIHR) under a Programme Grant for Applied Research (RP-PG-1209-10051)
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