210 research outputs found
Correction: Thermoresponsive polysarcosine-based nanoparticles
Correction for ‘Thermoresponsive polysarcosine-based nanoparticles’ by Huayang Yu et al., J. Mater. Chem. B, 2019, 7, 4217–4223
Closed-loop separation control over a sharp edge ramp using Genetic Programming
We experimentally perform open and closed-loop control of a separating
turbulent boundary layer downstream from a sharp edge ramp. The turbulent
boundary layer just above the separation point has a Reynolds number
based on momentum thickness. The goal of the
control is to mitigate separation and early re-attachment. The forcing employs
a spanwise array of active vortex generators. The flow state is monitored with
skin-friction sensors downstream of the actuators. The feedback control law is
obtained using model-free genetic programming control (GPC) (Gautier et al.
2015). The resulting flow is assessed using the momentum coefficient, pressure
distribution and skin friction over the ramp and stereo PIV. The PIV yields
vector field statistics, e.g. shear layer growth, the backflow area and vortex
region. GPC is benchmarked against the best periodic forcing. While open-loop
control achieves separation reduction by locking-on the shedding mode, GPC
gives rise to similar benefits by accelerating the shear layer growth.
Moreover, GPC uses less actuation energy.Comment: 24 pages, 24 figures, submitted to Experiments in Fluid
How do hospitals respond to feedback about blood transfusion practice? A multiple case study investigation
National clinical audits play key roles in improving care and driving system-wide change. However, effects of audit and feedback depend upon both reach (e.g. relevant staff receiving the feedback) and response (e.g. staff regulating their behaviour accordingly). This study aimed to investigate which hospital staff initially receive feedback and formulate a response, how feedback is disseminated within hospitals, and how responses are enacted (including barriers and enablers to enactment). Using a multiple case study approach, we purposively sampled four UK hospitals for variation in infrastructure and resources. We conducted semi-structured interviews with staff from transfusion-related roles and observed Hospital Transfusion Committee meetings. Interviews and analysis were based on the Theoretical Domains Framework of behaviour change. We coded interview transcripts into theoretical domains, then inductively identified themes within each domain to identify barriers and enablers. We also analysed data to identify which staff currently receive feedback and how dissemination is managed within the hospital. Members of the hospital's transfusion team initially received feedback in all cases, and were primarily responsible for disseminating and responding, facilitated through the Hospital Transfusion Committee. At each hospital, key individuals involved in prescribing transfusions reported never having received feedback from a national audit. Whether audits were discussed and actions explicitly agreed in Committee meetings varied between hospitals. Key enablers of action across all cases included clear lines of responsibility and strategies to remind staff about recommendations. Barriers included difficulties disseminating to relevant staff and needing to amend feedback to make it appropriate for local use. Appropriate responses by hospital staff to feedback about blood transfusion practice depend upon supportive infrastructures and role clarity. Hospitals could benefit from support to disseminate feedback systematically, particularly to frontline staff involved in the behaviours being audited, and practical tools to support strategic decision-making (e.g. action-planning around local response to feedback)
Combined aerobic and resistance exercise training decreases peripheral but not central artery wall thickness in subjects with type 2 diabetes
Objective
Little is known about the impact of exercise training on conduit artery wall thickness in type 2 diabetes. We examined the local and systemic impact of exercise training on superficial femoral (SFA), brachial (BA), and carotid artery (CA) wall thickness in type 2 diabetes patients and controls.
Methods
Twenty patients with type 2 diabetes and 10 age- and sex-matched controls performed an 8-week training study involving lower limb-based combined aerobic and resistance exercise training. We examined the SFA to study the local effect of exercise, and also the systemic impact of lower limb-based exercise training on peripheral (i.e. BA) and central (i.e. CA) arteries. Wall thickness (WT), diameter and wall:lumen(W:L)-ratios were examined using automated edge detection of ultrasound images.
Results
Exercise training did not alter SFA or CA diameter in type 2 diabetes or controls (all P > 0.05). BA diameter was increased after training in type 2 diabetes, but not in controls. Exercise training decreased WT and W:L ratio in the SFA and BA, but not in CA in type 2 diabetes. Training did not alter WT or W:L ratio in controls (P > 0.05).
Conclusion
Lower limb-dominant exercise training causes remodelling of peripheral arteries, supplying active and inactive vascular beds, but not central arteries in type 2 diabetes
Oral dosing of rodents using a palatable tablet
Rationale: Delivering orally bioavailable drugs to rodents is an important component to investigating that route of administration in novel treatments for humans. However, the traditional method of oral gavage requires training, is stressful, and can induce oesophageal damage in rodents. Objectives: To demonstrate a novel administrative technique – palatable gelatine tablets – as a stress-free route of oral delivery. Methods: 24 male Lister hooded rats were sacrificed for brain tissue analysis at varying time-points after jelly administration of 30 mg/kg of the wake-promoting drug modafinil. A second group of 22 female rats were tested on locomotor activity after 30 mg/kg modafinil, or after vehicle jellies, with the locomotor data compared to the brain tissue concentrations at the corresponding times. Results: Modafinil was present in the brain tissue at all time-points, reducing in concentration over time. The pattern of brain tissue modafinil concentration is comparable to previously reported results following oral gavage. Modafinil-treated rats were more active than control rats, with greater activity during the later time-periods – similar to that previously reported following intraperitoneal injection of 40 mg/kg modafinil. Conclusions: Palatable jelly tablets are an effective route of administration of thermally-stable orally-bioavailable compounds, eliminating the stress/discomfort and health risk of oral gavage and presenting as an alternative to previously reported palatable routes of administration where high protein and fat levels may adversely affect appetite for food reward, and uptake rate in the gastrointestinal tract.Publisher PDFPeer reviewe
Recent patterns in chronic disease mortality in remote living Indigenous Australians
Background: Despite the well-recognised Indigenous-non-Indigenous health disparity, some reports suggest improvements in Indigenous mortality. Our aim was to quantify Indigenous mortality in Outer Regional (OR), Remote (R), and Very Remote (VR) areas in New South Wales, Queensland, South Australia, Western Australia, and the Northern Territory and changes in mortality from 1998 to 2005
Profiles of responses of immunological factors to different subtypes of Kawasaki disease
Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile
Unconsolidated pyroclastic flow deposits of the
1993 eruption of Lascar Volcano, Chile, have, with time,
become increasingly dissected by a network of deeply
penetrating fractures. The fracture network comprises
orthogonal sets of decimeter-wide linear voids that form a
pseudo-polygonal grid visible on the deposit surface. In this
work, we combine shallow surface geophysical imaging
tools with remote sensing observations and direct field
measurements of the deposit to investigate these fractures
and their underlying causal mechanisms. Based on ground
penetrating radar images, the fractures are observed to have
propagated to depths of up to 10 m. In addition, orbiting radar interferometry shows that deposit subsidence of up to
1 cm/year occurred between 1993 and 1996 with continued
subsidence occurring at a slower rate thereafter. In situ
measurements show that 1 m below the surface, the 1993
deposits remain 5°C to 15°C hotter, 18 years after
emplacement, than adjacent deposits. Based on the observed
subsidence as well as estimated cooling rates, the fractures are
inferred to be the combined result of deaeration, thermal
contraction, and sedimentary compaction in the months to
years following deposition. Significant environmental factors,
including regional earthquakes in 1995 and 2007, accelerated
settling at punctuated moments in time. The spatially variable
fracture pattern relates to surface slope and lithofacies
variations as well as substrate lithology. Similar fractures
have been reported in other ignimbrites but are generally
exposed only in cross section and are often attributed to
formation by external forces. Here we suggest that such
interpretations should be invoked with caution, and deformation
including post-emplacement subsidence and fracturing of
loosely packed ash-rich deposits in the months to years postemplacement
is a process inherent in the settling of pyroclastic
material
Impact of surface adhesion and sample heterogeneity on the multiscale mechanical characterisation of soft biomaterials
Funding from the Engineering and Physical Sciences Research Council (EP/L505602/1) is gratefully acknowledged
Metabolic assessment of a novel chronic myelogenous leukemic cell line and an imatinib resistant subline by 1H NMR spectroscopy
The goal of this study was to examine metabolic differences between a novel chronic myelogenous leukemic (CML) cell line, MyL, and a sub-clone, MyL-R, which displays enhanced resistance to the targeted Bcr-Abl tyrosine kinase inhibitor imatinib. 1H nuclear magnetic resonance (NMR) spectroscopy was carried out on cell extracts and conditioned media from each cell type. Both principal component analysis (PCA) and specific metabolite identification and quantification were used to examine metabolic differences between the cell types. MyL cells showed enhanced glucose removal from the media compared to MyL-R cells with significant differences in production rates of the glycolytic end-products, lactate and alanine. Interestingly, the total intracellular creatine pool (creatine + phosphocreatine) was significantly elevated in MyL-R compared to MyL cells. We further demonstrated that the MyL-R cells converted the creatine to phosphocreatine using non-invasive monitoring of perfused alginate-encapsulated MyL-R and MyL cells by in vivo 31P NMR spectroscopy and subsequent HPLC analysis of extracts. Our data demonstrated a clear difference in the metabolite profiles of drug-resistant and sensitive cells, with the biggest difference being an elevation of creatine metabolites in the imatinib-resistant MyL-R cells
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