662 research outputs found

    Microscopic model of diffusion limited aggregation and electrodeposition in the presence of levelling molecules

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    A microscopic model of the effect of unbinding in diffusion limited aggregation based on a cellular automata approach is presented. The geometry resembles electrochemical deposition - ``ions'' diffuse at random from the top of a container until encountering a cluster in contact with the bottom, to which they stick. The model exhibits dendritic (fractal) growth in the diffusion limited case. The addition of a field eliminates the fractal nature but the density remains low. The addition of molecules which unbind atoms from the aggregate transforms the deposit to a 100% dense one (in 3D). The molecules are remarkably adept at avoiding being trapped. This mimics the effect of so-called ``leveller'' molecules which are used in electrochemical deposition

    Pulse-lavage brushing followed by hydrogen peroxide-gauze packing for bone-bed preparation in cemented total hip arthroplasty : a bovine model

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    To compare the effectiveness of pulse-lavage brushing followed by hydrogen peroxide-gauze packing with either technique alone or normal-saline irrigation in bone-bed preparation for cemented total hip arthroplasty. 44 fresh-frozen ox femoral canals were prepared for cemented total hip arthroplasty using 4 techniques: normal-saline irrigation, pulse-lavage brushing, hydrogen peroxide-soaked gauze packing, and a combination of the latter 2 techniques. The maximum tensile pull-out force required to separate the prosthesis from the femoral canal was measured as an indicator of the strength of the cement-bone interface. The mean pull-out force to separate the prosthesis from the femoral canal was significantly higher in specimens prepared with pulse-lavage brushing followed by hydrogen peroxide-soaked gauze packing or pulse-lavage brushing alone than those prepared with normal-saline irrigation or hydrogen peroxide-soaked gauze packing alone 300(p&lt;0.001). Pulse-lavage brushing is more effective at cleansing the femoral canal and increasing mechanical strength at the cement-bone interface than preparation with normal-saline irrigation or hydrogen peroxide-soaked gauze packing.<br /

    Nuts \u27n\u27 guts: transport of food allergens across the intestinal epithelium

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    The increase in the incidence of food allergy is a growing problem for the western world. This review will focus on the findings from several macromolecular epithelial transport experiments and drug permeability studies to provide a recent comprehension of food allergen intestinal epithelial cell transport and the allergen-epithelial relationship. Specifically, this review will aim to answer whether allergens can permeate the intestinal barrier directly via intestinal epithelial cells, and whether this mode of transport affects downstream immune reactions. By improving our understanding of the interactions which take place during exposure of food allergens with the intestinal epithelium, we can begin to understand whether the epithelial barrier plays a major role in the allergic sensitization process rather than simply restricting the entry of allergens to the underlying lamina propria

    Novel biomarkers in critical care: utility or futility?

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    One of the holy grails of modern medicine, across a range of clinical sub-specialties, is establishing highly sensitive and specific biomarkers for various diseases. Significant success has been achieved in some of these clinical areas, most notably identifying high-sensitivity C-reactive peptide, troponin I/T and brain natriuretic peptide as significant prognosticators for both the acute outcome and the development of cardiovascular pathology. However, it is highly debatable whether this translates to complex, multi-system pathophysiological insults. Is critical care immune from the application of these novel biomarkers, given the numerous confounding factors interfering with their interpretation

    THE ART ATHLETE: A SPORTS BIOMECHANICS PERSPECTIVE

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    Overuse injuries are as much a problem for ‘art athletes’ (dancers and musicians and performing artists generally) as they are for those we more commonly term ‘athletes’. Lower back injuries in male ballet dancers are certainly commonplace. 3D motion analysis in combination with 3D Static Strength Predicting analysis showed that compressive forces at L5/S1 were above the National Institute of Occupational Safety and Health ‘Back Compression Design Limit’ (~ 4,500N) and shear forces were high (~ 530 N) for male dancers performing two commonly used classical lifts. A research design for the use of an opto-reflective motion analysis (Vicon) to investigate shoulder joint loading in cellists and violinists will also be presented

    Effect of Cluster Formation on Isospin Asymmetry in the Liquid-Gas Phase Transition Region

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    Nuclear matter within the liquid-gas phase transition region is investigated in a mean-field two-component Fermi-gas model. Following largely analytic considerations, it is shown that: (1) Due to density dependence of asymmetry energy, some of the neutron excess from the high-density phase could be expelled into the low-density region. (2) Formation of clusters in the gas phase tends to counteract this trend, making the gas phase more liquid-like and reducing the asymmetry in the gas phase. Flow of asymmetry between the spectator and midrapidity region in reactions is discussed and a possible inversion of the flow direction is indicated.Comment: 9 pages,3 figures, RevTe

    G94-1210 Borers of Shade Trees and Ornamental Plants

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    This publication describes the important shade tree and ornamental borers in Nebraska and discusses their management. Nearly all shade trees are subject to borer attack. If damage is severe, young trees are likely to decline or die

    G94-1210 Borers of Shade Trees and Ornamental Plants

    Get PDF
    This publication describes the important shade tree and ornamental borers in Nebraska and discusses their management. Nearly all shade trees are subject to borer attack. If damage is severe, young trees are likely to decline or die
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