4,967 research outputs found
Predictions for the fracture toughness of cancellous bone of fracture neck of femur patients
Current protocol in determining if a patient is osteoporotic and their fracture risk is based on dual energy X-ray absorptiometry (DXA). DXA gives an indication of their bone mineral density (BMD) which is the product of both the porosity and density of the mineralized bone tissue; this is usually taken at the hip. The DXA results are assessed using the fracture risk assessment tool as recommended by the World Health Organization. While this provides valuable data on a personâs fracture risk advancements in medical imagining technology enables development of more robust and accurate risk assessment tools. In order to develop such tools in vitro analysis of bone is required to assess the morphological properties of bone osteoporotic bone tissue and how these pertain to the fracture toughness (Kcmax) of the tissue.Support was provided by the EPSRC (EP/K020196: Point-ofCare High Accuracy Fracture Risk Prediction), the UK Department of Transport under the BOSCOS (Bone Scanning for Occupant Safety) project, and approved by Gloucester and Cheltenham NHS Trust hospitals under ethical consent (BOSCOS â Mr. Curwen CI REC ref 01/179G)
Proton - Lambda correlations in Au-Au Collisions at GeV from the STAR experiment
The space-time evolution of the source of particles formed in the collision
of nuclei can be studied through particle correlations. The STAR experiment is
dedicated to study ultra-relativistic heavy ions collisions and allows to
measure non-identical strange particle correlations. The source size can be
extracted by studying , ,
and correlation functions. Strong interaction potential has
been studied for these systems using an analytical model. Final State
Interaction (FSI) parameters have been determined and has shown a significant
annihilation process present in and systems
not present in and .Comment: contribution to the 20th Winter Workshop on Nuclear Dynamic
Incident-energy and system-size dependence of directed flow
We present STAR's measurements of directed flow for charged hadrons in Au+Au
and Cu+Cu collisions at GeV and 62.4 GeV, as a
function of pseudorapidity, transverse momentum and centrality. We find that
directed flow depends on the incident energy, but not on the system size. We
extend the validity of limiting fragmentation hypothesis to different collision
systems.Comment: Quark Matter 2006 proceedings, 4 pages, 4 figures, submitted to J.
Phys.
Fracture toughness of the cancellous bone of FNF femoral heads in relation to its microarchitecture
This study considers the relationship between microarchitecture and mechanical properties for cancellous bone specimens collected from a cohort of patients who had suffered fractured necks of femur. OP
is an acute skeletal condition with huge socioeconomic impact [1] and it is associated with changes in both bone quantity and quality [2], which affect greatly the strength and toughness of the tissue [3].Support was provided by the EPSRC (EP/K020196: Point-ofCare High Accuracy Fracture Risk Prediction), the UK Department of Transport under the BOSCOS (Bone Scanning for Occupant Safety) project, and approved by Gloucester and Cheltenham NHS Trust hospitals under ethical consent (BOSCOS â Mr. Curwen CI REC ref 01/179G)
Holocene record of Tuggerah Lake estuary development on the Australian east coast: sedimentary responses to sea-level fluctuations and climate variability
We investigated the Holocene palaeo-environmental record of the Tuggerah Lake barrier estuary on the south-east coast of Australia to determine the influence of local, regional and global environmental changes on estuary development. Using multi-proxy approaches, we identified significant down-core variation in sediment cores relating to sea-level rise and regional climate change. Following erosion of the antecedent land surface during the post-glacial marine transgression, sediment began to accumulate at the more seaward location at ~8500. years before present, some 1500. years prior to barrier emplacement and ~4000. years earlier than at the landward site. The delay in sediment accumulation at the landward site was a consequence of exposure to wave action prior to barrier emplacement, and due to high river flows of the mid-Holocene post-barrier emplacement. As a consequence of the mid-Holocene reduction in river flows, coupled with a moderate decline in sea-level, the lake experienced major changes in conditions at ~4000. years before present. The entrance channel connecting the lake with the ocean became periodically constricted, producing cyclic alternation between intervals of fluvial- and marine-dominated conditions. Overall, this study provides a detailed, multi-proxy investigation of the physical evolution of Tuggerah Lake with causative environmental processes that have influenced development of the estuary
Recommended from our members
The Barbados Insulin Matters (BIM) study: Barriers to insulin therapy among a population-based sample of people with type 2 diabetes in the Caribbean island of Barbados.
AIM: The purpose of this study was to document in people with type 2 diabetes (T2DM) in Barbados, attitudes and beliefs that may result in psychological insulin resistance. METHODS: A representative, population-based, sample of 175 eligible people with T2DM 25 years of age and over was surveyed by telephone. The 20-item insulin treatment appraisal scale (ITAS) was administered (score range 20 to 100 for positive to negative perceptions). RESULTS: 117 people participated (67% response rate, 32% male, mean age 66 years, 90% Black, 22% on insulin). Of non-responders, 52 were not contactable and 6 were difficult to communicate with. Negative perceptions about insulin use included - meant a worsening of diabetes (68%), would worry family (63%), feared self-injection (58%), meant a failure in self-management (57%), injections were painful (54%), would be seen as being sicker (46%), increased hypoglycaemia risk (38%), required effort (34%), causes weight gain (27%), causes a deterioration in health (14%), and would have to give up enjoyable activities (10%). Positive perceptions were - helps good glycaemic control (78%), would prevent complications (61%) and improves health (58%). Mean total ITAS score (61.6, SD = 7.7) was lower for those on insulin compared to those not on insulin (53.7 vs. 63.8, p < 0.0001). Sex, age and diabetes diagnosis duration were not significant predictors of ITAS score. CONCLUSIONS: Multiple factors related to patient beliefs and attitudes need to be considered and addressed when initiating insulin in order to minimise psychological insulin resistance and delay. Patients using insulin had less negative perceptions than those not on insulin
Do ENSO and coastal development enhance coastal burial of terrestrial carbon?
Carbon cycling on the east coast of Australia has the potential to be strongly affected by El Niño-Southern Oscillation (ENSO) intensification and coastal development (industrialization and urbanization). We performed paleoreconstructions of estuarine sediments from a seagrass-dominated estuary on the east coast of Australia (Tuggerah Lake, New South Wales) to test the hypothesis that millennial-scale ENSO intensification and European settlement in Australia have increased the transfer of organic carbon from land into coastal waters. Our data show that carbon accumulation rates within coastal sediments increased significantly during periods of maximum millennial-scale ENSO intensity ("super-ENSO") and coastal development. We suggest that ENSO and coastal development destabilize and liberate terrestrial soil carbon, which, during rainfall events (e.g., La Niña), washes into estuaries and becomes trapped and buried by coastal vegetation (seagrass in this case). Indeed, periods of high carbon burial were generally characterized as having rapid sedimentation rates, higher content of fine-grained sediments, and increased content of wood and charcoal fragments. These results, though preliminary, suggest that coastal development and ENSO intensificationboth of which are predicted to increase over the coming centurycan enhance capture and burial of terrestrial carbon by coastal ecosystems. These findings have important relevance for current efforts to build an understanding of terrestrial- marine carbon connectivity into global carbon budgets
Renormalization-Scale-Invariant PQCD Predictions for R_e+e- and the Bjorken Sum Rule at Next-to-Leading Order
We discuss application of the physical QCD effective charge ,
defined via the heavy-quark potential, in perturbative calculations at
next-to-leading order. When coupled with the Brodsky-Lepage-Mackenzie
prescription for fixing the renormalization scales, the resulting series are
automatically and naturally scale and scheme independent, and represent
unambiguous predictions of perturbative QCD. We consider in detail such
commensurate scale relations for the annihilation ratio
and the Bjorken sum rule. In both cases the improved predictions are in
excellent agreement with experiment.Comment: 13 Latex pages with 5 figures; to be published in Physical Review
Modelling of Brain Deformation After Decompressive Craniectomy.
Hyperelastic finite element models, with either an idealized cylindrical geometry or with realistic craniectomy geometries, were used to explore clinical issues relating to decompressive craniectomy. The potential damage in the brain tissue was estimated by calculating the volume of material exceeding a critical shear strain. Results from the idealized model showed how the potentially damaged volume of brain tissue increased with an increasing volume of brain tissue herniating from the skull cavity and with a reduction in craniectomy area. For a given herniated volume, there was a critical craniectomy diameter where the volume exceeding a critical shear strain fell to zero. The effects of details at the craniectomy edge, specifically a fillet radius and a chamfer on the bone margin, were found to be relatively slight, assuming that the dura is retained to provide effective protection. The location in the brain associated with volume expansion and details of the material modeling were found to have a relatively modest effect on the predicted damage volume. The volume of highly sheared material in the realistic models of the craniectomy varied roughly in line with differences in the craniectomy area.TLF acknowledges funding from the Engineering and Physical Sciences Research Council (EPSRC). BW is supported by the Studienstiftung des deutschen Volkes, the Max Weber-Programm and the Stiftung Maximilianeum. AGK is supported by a Royal College of Surgeons of England Research Fellowship (funded by the Freemasons and the Rosetrees Trust), a National Institute of Health Research (NIHR) Academic Clinical Fellowship and a Raymond and Beverly Sackler Studentship. PJH is supported by a NIHR Research Professorship and the NIHR Cambridge Biomedical Research Centre.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s10439-016-1666-
- âŠ