56,051 research outputs found
Angioedema due to acquired C1-esterase inhibitor deficiency in a patient with heliobacter pylori infection - Comment
No full textAngioedema due to acquired C1-esterase inhibitor deficiency in a patient with heliobacter pylori infection - Comment
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Plasminogen activities and concentrations in patients with sporadic Creutzfeldt-Jakob disease
No full textHuman plasminogen has been shown to interact with the abnormal disease-specific prion protein. Till now, no data are available for patients with Creutzfeldt-Jakob disease (CJD). Therefore, we compared plasminogen concentrations and plasminogen activities in patients with sporadic CJD and controls with other dementia, which were collected in the framework of the German CJD Surveillance study. Patients with CJD had significantly higher plasminogen concentrations than patients with other forms of dementia and plasminogen specific activities were lower in CJD patients. The reasons for these abnormalities are Dot clear at the moment. The results may reflect a disease-specific prion protein and plasminogen interaction in patients with CJD. Other possible explanations are plasminogen polymorphisms and genotypes with distinct plasminogen activity levels in CJD than in controls, which should be a subject for further studies. (C) 2004 Elsevier Ireland Ltd. All rights reserved
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
Large-eddy simulation of a separated flow with a sub-filter scale model based on the integral length-scale
No full textA new sub-filter scale model for large-eddy simulations, which uses a length-scale proportional to the integral scale of the turbulence instead of the grid resolution to parametrize the modelled stresses, will be assessed in the prediction of the flow of a boundary-layer over a rough surface, which includes separation and reattachment
Near Wall PIV-Measurements on the Windward Slope of a Hill
No full textThe turbulent flow over periodic hills was measured near to the wall, using planar Particle-Image-Velocimetry (PIV) at high spatial resolution. Our focus is on the near wall turbulence structure on the windward slope of the hill. For large-eddy simulation (LES) we suspect that, if this was not predicted accurately, it affects the prediction of the velocity profiles over the hill crest which in turn will affect the recirculation length downstream of the hill. Regarding the time averaged velocities, we were able to resolve the linear viscous region of the boundary layer. The velocity distribution and also the Reynolds stress does not comply with the law of the wall as it is valid for a turbulent boundary layer at equilibrium
Polyneuropathy as a sole syndrome in mialignant thymoma
No full textUp to 40% of patients with malignant thymoma suffer from paraneoplastic symptoms (90% myasthenia, 10% other symptoms). A 55-year-old patient developed ascending symmetrical, sensorimotor tetraparesis. A malignant thymoma without metastases was diagnosed 6 months, later. Despite thymectomy followed by radiation and high-dose corticosteroid therapy, the, polyneuropathy progressed. Six months after onset, the patient was bound to a wheelchair. Immunosuppressive therapy with cyclophosphamide was initiated, leading to marked remission. After ten cycles, the patient was able to walk independently with walking aids. After the sixth and tenth cycle, respectively, attempts to discontinue immunosuppression led to relapse. In several diagnostic workups, however, there was no tumour relapse. After 13 cycles, cyclophosphamide was replaced by immunoglobulins (0.4 g/kg per day i.v. for 5 days/month) due to progressive renal failure. The patient died just before the secondcourse of this treatment. In conclusion, in the differential diagnosis of rapidly progressive polyneuropathy a malignant thymoma should be considered, even in the absence of myasthenia. Immunosuppression with cyclophosphamide resulted in amelioration of symptoms in this patient
Energy dissipation and flux laws for unsteady turbulence
No full textDirect Numerical Simulations of spatially periodic unsteady turbulence show that the high Reynolds number scalings of the instantaneous energy dissipation rate and interscale energy flux at intermediate wavenumbers are qualitatively different from the well-known cornerstone scalings of equilibrium turbulence where and are time-dependent rms velocity and integral length-scales. Instead, they both scale as where and are length and velocity scales characterizing initial/overall unsteady turbulence conditions
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
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