1,567 research outputs found

    Risk of septic knee following retrograde intramedullary nailing of open and closed femur fractures

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    <p>Abstract</p> <p>Background</p> <p>One potential complication of retrograde femoral nailing in the treatment of femur fractures is the risk of septic knee. This risk theoretically increases in open fractures as a contaminated fracture site has the potential to seed the instrumentation being passed in and out of the sterile intraarticular starting point. There are few studies examining this potential complication in a relatively commonly practiced technique.</p> <p>Methods</p> <p>All patients who received a retrograde femoral nail for femur fracture between September 1996 and November 2006 at a Level 1 trauma center were retrospectively reviewed. This yielded 143 closed fractures, 38 open fractures and 4 closed fractures with an ipsilateral traumatic knee arthrotomy. Patient follow-up records were reviewed for documentation of septic knee via operative notes, wound culture or knee aspirate data, or the administration of antibiotics for suspected septic knee.</p> <p>Results</p> <p>No evidence of septic knee was found in the 185 fractures examined in the dataset. Utilizing the Wilson confidence interval, the rate of septic knee based on our population was no greater than 2%, with that of the open fracture group alone being 9%.</p> <p>Conclusions</p> <p>Based on these results and review of the literature, the risk of septic knee in retrograde femoral nailing of both open and closed femoral shaft fractures appears low but potentially not insignificant.</p> <p>Funding</p> <p>There was no outside source of funding from either industry or other organization for this study.</p

    Orthogonality Catastrophe in Parametric Random Matrices

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    We study the orthogonality catastrophe due to a parametric change of the single-particle (mean field) Hamiltonian of an ergodic system. The Hamiltonian is modeled by a suitable random matrix ensemble. We show that the overlap between the original and the parametrically modified many-body ground states, SS, taken as Slater determinants, decreases like nkx2n^{-k x^2}, where nn is the number of electrons in the systems, kk is a numerical constant of the order of one, and xx is the deformation measured in units of the typical distance between anticrossings. We show that the statistical fluctuations of SS are largely due to properties of the levels near the Fermi energy.Comment: 12 pages, 8 figure

    Theoretical Studies of Spectroscopy and Dynamics of Hydrated Electrons.

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    Semileptonic B decays into excited charmed mesons from QCD sum rules

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    Exclusive semileptonic BB decays into excited charmed mesons are studied with QCD sum rules in the leading order of heavy quark effective theory. Two universal Isgur-Wise functions \tau and \zeta for semileptonic B decays into four lowest lying excited DD mesons (D1D_1, D2D_2^*, D0D'_0, and D1D'_1) are determined. The decay rates and branching ratios for these processes are calculated.Comment: RevTeX, 17 pages including 2 figure

    Three-dimensional quantization of the electromagnetic field in dispersive and absorbing inhomogeneous dielectrics

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    A quantization scheme for the phenomenological Maxwell theory of the full electromagnetic field in an inhomogeneous three-dimensional, dispersive and absorbing dielectric medium is developed. The classical Maxwell equations with spatially varying and Kramers-Kronig consistent permittivity are regarded as operator-valued field equations, introducing additional current- and charge-density operator fields in order to take into account the noise associated with the dissipation in the medium. It is shown that the equal-time commutation relations between the fundamental electromagnetic fields E^\hat E and B^\hat B and the potentials A^\hat A and ϕ^\hat \phi in the Coulomb gauge can be expressed in terms of the Green tensor of the classical problem. From the Green tensors for bulk material and an inhomogeneous medium consisting of two bulk dielectrics with a common planar interface it is explicitly proven that the well-known equal-time commutation relations of QED are preserved

    Investigating associations between the built environment and physical activity among older people in 20 UK towns.

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    BACKGROUND: Policy initiatives such as WHO Age Friendly Cities recognise the importance of the urban environment for improving health of older people, who have both low physical activity (PA) levels and greater dependence on local neighbourhoods. Previous research in this age group is limited and rarely uses objective measures of either PA or the environment. METHODS: We investigated the association between objectively measured PA (Actigraph GT3x accelerometers) and multiple dimensions of the built environment, using a cross-sectional multilevel linear regression analysis. Exposures were captured by a novel foot-based audit tool that recorded fine-detail neighbourhood features relevant to PA in older adults, and routine data. RESULTS: 795 men and 638 women aged 69-92 years from two national cohorts, covering 20 British towns, were included in the analysis. Median time in moderate to vigorous PA (MVPA) was 27.9 (lower quartile: 13.8, upper quartile: 50.4) minutes per day. There was little evidence of associations between any of the physical environmental domains (eg, road and path quality defined by latent class analysis; number of bus stops; area aesthetics; density of shops and services; amount of green space) and MVPA. However, analysis of area-level income deprivation suggests that the social environment may be associated with PA in this age group. CONCLUSIONS: Although small effect sizes cannot be discounted, this study suggests that older individuals are less affected by their local physical environment and more by social environmental factors, reflecting both the functional heterogeneity of this age group and the varying nature of their activity spaces

    Ways of Relating: Hospitality and the acknowledgement of otherness

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    This paper considers the relevance of the work of Emmanuel Levinas and Jacques Derrida to geography’s engagements with both mainstream moral philosophy and poststructuralist theory. This relevance lies in the way in which their work unsettles the ascription of normative value to relations of proximity and distance. Distance is usually understood to be a medium of moral harm or indifference. In contrast, Levinas presents distance as the very condition of responsibility. Grasping the significance of this argument requires an appreciation of the temporality of responsibility and responsiveness that both Levinas and Derrida emphasise. They present an alternative way of understanding the relationality of subjectivity and social processes. Through a schematic exposition of key themes in Levinas’ work, prevalent understandings of the spatiality of relations are shown to harbour their own forms of indifference and moral harm. The full effect of Levinas’ reconsideration of the value of relations between proximity and distance is bought out in Derrida’s recent writings on hospitality. For both thinkers, there is no natural geographical scene for the cultivation of responsibility. Rather, their shared focus upon temporality emphasizes the degree to which responsibility is motivated in response to the activities of others. The implication of this argument is that critical analysis should be reoriented towards practices that shape individual and collective dispositions to acknowledge the claims of others

    γ-Aminobutyric Acid (GABA) Is an Autocrine Excitatory Transmitter in Human Pancreatic β-Cells

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    OBJECTIVE: Paracrine signaling via gamma-aminobutyric acid (GABA) and GABA(A) receptors (GABA(A)Rs) has been documented in rodent islets. Here we have studied the importance of GABAergic signaling in human pancreatic islets. RESEARCH DESIGN AND METHODS: Expression of GABA(A)Rs in islet cells was investigated by quantitative PCR, immunohistochemistry, and patch-clamp experiments. Hormone release was measured from intact islets. GABA release was monitored by whole-cell patch-clamp measurements after adenoviral expression of alpha(1)beta(1) GABA(A)R subunits. The subcellular localization of GABA was explored by electron microscopy. The effects of GABA on electrical activity were determined by perforated patch whole-cell recordings. RESULTS: PCR analysis detected relatively high levels of the mRNAs encoding GABA(A)R alpha(2), beta(3,) gamma(2), and pi subunits in human islets. Patch-clamp experiments revealed expression of GABA(A)R Cl(-) channels in 52% of beta-cells (current density 9 pA/pF), 91% of delta-cells (current density 148 pA/pF), and 6% of alpha-cells (current density 2 pA/pF). Expression of GABA(A)R subunits in islet cells was confirmed by immunohistochemistry. beta-Cells secreted GABA both by glucose-dependent exocytosis of insulin-containing granules and by a glucose-independent mechanism. The GABA(A)R antagonist SR95531 inhibited insulin secretion elicited by 6 mmol/l glucose. Application of GABA depolarized beta-cells and stimulated action potential firing in beta-cells exposed to glucose. CONCLUSIONS: Signaling via GABA and GABA(A)R constitutes an autocrine positive feedback loop in human beta-cells. The presence of GABA(A)R in non-beta-cells suggests that GABA may also be involved in the regulation of somatostatin and glucagon secretion

    The Radioecology Exchange

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    The Radioecology Exchange (www.radioecology-exchange.org) was created in 2011 under the EU FP7 STAR (STrategy for Allied Radioecology, www.star-radioecology.org) Network of Excellence; (2011-2015). This project aims to integrate radioecological research efforts of European organisations into a sustainable network. In 2013, the EU FP7 COMET (COordination and iMplementation of a pan-European instrumenT for radioecology (2013- 2017); www.comet-radioecology.org) project commenced; COMET will build upon the work initiated under STAR. The Radioecology Exchange has therefore become the web resource for activities from both projects which will ultimately be maintained by the European Radioecology Alliance (ALLIANCE; www.er-alliance.org). The Radioecology Exchange is intended to become a ‘gateway’ for information related to European (and wider) radioecological research
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