239 research outputs found
Opioid prescribing for acute postoperative pain : an overview of systematic reviews related to two consensus statements relevant at patient, prescriber, system and public health levels
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TRAIL part 2: a comprehensive assessment of ice particle fall speed parametrisations
Results are presented from a comprehensive experimental campaign studying the aerodynamics of 3D-printed analogues of ice particles. Measurements of the drag coefficient of the analogues were acquired by using a novel experimental approach to digitally reconstruct the analogues’ trajectory and orientation as they fall through a quiescent viscous liquid, using images acquired by a series of digital cameras. The data are used to evaluate commonly used parametrisations of ice particle fall speeds. We find that the accuracy of each of the parametrisations reduces at Reynolds numbers greater than approximately 100, as a result of effects associated with the onset of unsteady oscillating, fluttering or tumbling motions as the analogues fall. We propose a new fall-speed parametrisation that predicts the measured drag coefficients at high Reynolds number with an accuracy consistent with that of the leading parametrisation at low Reynolds number
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TRAIL: a novel approach for studying the aerodynamics of ice particles
A novel experimental approach for studying the aerodynamics of ice particles is presented. The Trajectory Reconstruction Algo- rithm implemented through Image anaLysis (TRAIL) produces digital reconstructions of the trajectory and orientation of 3D-printed analogues of ice particles that fall through a quiescent viscous liquid. Data extracted from this analysis can be used to test fall-speed parametrisations and investigate the preferred orientation of analogues with complex irregular geometries. Experiments using thin circular discs are used to validate this approach. Measurements from a case study in which an analogue of an aggregate ice particle is used are also reported. Data extracted from the analysis clearly demonstrate important, but poorly under- stood, aspects of the aerodynamics of atmospheric ice particles. For example, the orientation that the analogue adopts in free- fall is shown to depend not only on the geometric shape of the particle, but also on the Reynolds number at which it falls. In addition, measurements of the drag coefficient indicate that the accuracy of fall-speed parametrisations reduces at high Reynolds number due to the onset of unsteady motions
Serum 25-hydroxy vitamin D: a predictor of macrovascular and microvascular complications in patients with type 2 diabetes
Objective People with diabetes frequently develop vascular disease. We investigated the relationship between blood 25-hydroxy vitamin D (25OH-D) concentration and vascular disease risk in type 2 diabetes. Research design and methods The relationships between blood 25OH-D concentration at baseline and the incidence of macrovascular (including myocardial infarction, stroke) and microvascular (retinopathy, nephropathy, neuropathy, and amputation) disease were analysed with Cox proportional-hazards models and logistic regression in an observational study of patients in the 5-year Fenofibrate Intervention and Event Lowering in Diabetes trial. Results 50% of the patients had low vitamin D concentrations, as indicated by median blood 25OH-D concentration of 49nmol/L. These patients with a blood 25OH-D concentration < 50nmol/L had a higher cumulative incidence of macrovascular and microvascular events than those with levels ≥ 50nmol/L. Multivariate analysis, stratified by treatment and adjusted for relevant confounders, identified blood 25OH-D concentration as an independent predictor of macrovascular events. A 50nmol/L difference in blood 25OH-D concentration was associated with a 23% (P=0.007) change in risk of macrovascular complications during the study and further adjustments for seasonality, hs-CRP and physical activity level had little impact. The unadjusted risk of microvascular complications was 18% (P=0.006) higher during the study, though the excess risk declined to 11-14% and lost significance with adjustment for HbA1C, seasonality or physical activity. Conclusions Low blood 25OH-D concentrations are associated with an increased risk of macrovascular and microvascular disease events in type 2 diabetes. However, a causal link remains to be demonstrated
A generative approach for image-based modeling of tumor growth
22nd International Conference, IPMI 2011, Kloster Irsee, Germany, July 3-8, 2011. ProceedingsExtensive imaging is routinely used in brain tumor patients to monitor the state of the disease and to evaluate therapeutic options. A large number of multi-modal and multi-temporal image volumes is acquired in standard clinical cases, requiring new approaches for comprehensive integration of information from different image sources and different time points. In this work we propose a joint generative model of tumor growth and of image observation that naturally handles multi-modal and longitudinal data. We use the model for analyzing imaging data in patients with glioma. The tumor growth model is based on a reaction-diffusion framework. Model personalization relies only on a forward model for the growth process and on image likelihood. We take advantage of an adaptive sparse grid approximation for efficient inference via Markov Chain Monte Carlo sampling. The approach can be used for integrating information from different multi-modal imaging protocols and can easily be adapted to other tumor growth models.German Academy of Sciences Leopoldina (Fellowship Programme LPDS 2009-10)Academy of Finland (133611)National Institutes of Health (U.S.) (NIBIB NAMIC U54-EB005149)National Institutes of Health (U.S.) (NCRR NAC P41- RR13218)National Institutes of Health (U.S.) (NINDS R01-NS051826)National Institutes of Health (U.S.) (NIH R01-NS052585)National Institutes of Health (U.S.) (NIH R01-EB006758)National Institutes of Health (U.S.) (NIH R01-EB009051)National Institutes of Health (U.S.) (NIH P41-RR014075)National Science Foundation (U.S.) (CAREER Award 0642971
The International Law of Secession and the Protection of the Human Rights of Oppressed Sub-State Groups: Yesterday, Today and Tomorrow
This paper focuses on significant patterns/features in the historical development of the international law of secession and its contribution over time (or the lack thereof) to the struggle to afford greater protection to oppressed sub-state groups the world over. It was Crawford Young who once observed that “the state as an analytical quarry is an elusive and complex prey.” With the necessary modifications, this observation applies with almost equal force to the international law of secession. Complexity and confusion loom too large in this area of international law. For example, there is, at best, little clarity in the literature of the discipline of international law and in related fields of study regarding the existence or otherwise of an international legal entitlement to secession in favor of even the most highly oppressed and subjugated sub-state groups
Gene Expression Changes Associated with the Airway Wall Response to Injury
Understanding the way in which the airway heals in response to injury is fundamental to dissecting the mechanisms underlying airway disease pathology. As only limited data is available in relation to the in vivo characterisation of the molecular features of repair in the airway we sought to characterise the dynamic changes in gene expression that are associated with the early response to physical injury in the airway wall.We profiled gene expression changes in the airway wall using a large animal model of physical injury comprising bronchial brush biopsy in anaesthetised sheep. The experimental design featured sequential studies in the same animals over the course of a week and yielded data relating to the response at 6 hours, and 1, 3 and 7 days after injury. Notable features of the transcriptional response included the early and sustained preponderance of down-regulated genes associated with angiogenesis and immune cell activation, selection and differentiation. Later features of the response included the up-regulation of cell cycle genes at d1 and d3, and the latter pronounced up-regulation of extracellular matrix-related genes at d3 and d7.It is possible to follow the airway wall response to physical injury in the same animal over the course of time. Transcriptional changes featured coordinate expression of functionally related genes in a reproducible manner both within and between animals. This characterisation will provide a foundation against which to assess the perturbations that accompany airway disease pathologies of comparative relevance
Transcriptional and Post-Transcriptional Regulation of SPAST, the Gene Most Frequently Mutated in Hereditary Spastic Paraplegia
Hereditary spastic paraplegias (HSPs) comprise a group of neurodegenerative disorders that are characterized by progressive spasticity of the lower extremities, due to axonal degeneration in the corticospinal motor tracts. HSPs are genetically heterogeneous and show autosomal dominant inheritance in ∼70–80% of cases, with additional cases being recessive or X-linked. The most common type of HSP is SPG4 with mutations in the SPAST gene, encoding spastin, which occurs in 40% of dominantly inherited cases and in ∼10% of sporadic cases. Both loss-of-function and dominant-negative mutation mechanisms have been described for SPG4, suggesting that precise or stoichiometric levels of spastin are necessary for biological function. Therefore, we hypothesized that regulatory mechanisms controlling expression of SPAST are important determinants of spastin biology, and if altered, could contribute to the development and progression of the disease. To examine the transcriptional and post-transcriptional regulation of SPAST, we used molecular phylogenetic methods to identify conserved sequences for putative transcription factor binding sites and miRNA targeting motifs in the SPAST promoter and 3′-UTR, respectively. By a variety of molecular methods, we demonstrate that SPAST transcription is positively regulated by NRF1 and SOX11. Furthermore, we show that miR-96 and miR-182 negatively regulate SPAST by effects on mRNA stability and protein level. These transcriptional and miRNA regulatory mechanisms provide new functional targets for mutation screening and therapeutic targeting in HSP
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