100 research outputs found
Patterns and predictors of statin prescription in patients with type 2 diabetes
<p>Abstract</p> <p>Background</p> <p>The benefit of statins for prevention of cardiovascular events in type 2 diabetes is established, but a gap exists between guideline recommendations and clinical practice. The aim of the study was to identify patient-related factors predicting statin prescription.</p> <p>Methods</p> <p>We assessed the quality of care in 51,640 patients with type 2 diabetes in a German diabetes registry. Patients were stratified according to primary and secondary prevention. Five-year risk for cardiovascular events was calculated in primary prevention patients. A multivariate adjusted logistic regression model was constructed to determine which parameters influenced statin prescription.</p> <p>Results</p> <p>34% had established atherosclerotic disease and 25.5% received a statin. Prescription was significantly higher in the secondary compared to the primary prevention group (38.1% [95% CI 37.4–38.9%] vs. 18.5% [95% CI 18.0–19.0%], respectively). In primary prevention the odds for statin prescription increased with estimated cardiovascular risk (OR 1.17 per 5% increase in 5-year risk, 95% CI 1.11–1.22). Positive predictors for statin prescription were secondary prevention, hypertension, former smoking, baseline LDL-cholesterol, and microalbuminuria. The odds of receiving a statin had an inverted U-shaped relation with age (nadir, 66 years), age at first diagnosis of diabetes (nadir, 56 years), and body mass index (nadir, 32 kg/m<sup>2</sup>). The model predicted prescription in 70% of the patients correctly.</p> <p>Conclusion</p> <p>The majority of patients with type 2 diabetes are not receiving statins. The predominant factors determining statin prescription are the patient's prevention status and, in primary prevention, estimated cardiovascular risk. The results suggest that although physicians are aware of the general concept of cardiovascular risk, they fail to consistently implement guidelines.</p
Dewetting of thin films on heterogeneous substrates: Pinning vs. coarsening
We study a model for a thin liquid film dewetting from a periodic
heterogeneous substrate (template). The amplitude and periodicity of a striped
template heterogeneity necessary to obtain a stable periodic stripe pattern,
i.e. pinning, are computed. This requires a stabilization of the longitudinal
and transversal modes driving the typical coarsening dynamics during dewetting
of a thin film on a homogeneous substrate. If the heterogeneity has a larger
spatial period than the critical dewetting mode, weak heterogeneities are
sufficient for pinning. A large region of coexistence between coarsening
dynamics and pinning is found.Comment: 4 pages, 4 figure
Emergence of Order in Textured Patterns
A characterization of textured patterns, referred to as the disorder function
\bar\delta(\beta), is used to study properties of patterns generated in the
Swift-Hohenberg equation (SHE). It is shown to be an intensive,
configuration-independent measure. The evolution of random initial states under
the SHE exhibits two stages of relaxation. The initial phase, where local
striped domains emerge from a noisy background, is quantified by a power law
decay \bar\delta(\beta) \sim t^{-{1/2} \beta}. Beyond a sharp transition a
slower power law decay of \bar\delta(\beta), which corresponds to the
coarsening of striped domains, is observed. The transition between the phases
advances as the system is driven further from the onset of patterns, and
suitable scaling of time and \bar\delta(\beta) leads to the collapse of
distinct curves. The decay of during the initial phase
remains unchanged when nonvariational terms are added to the underlying
equations, suggesting the possibility of observing it in experimental systems.
In contrast, the rate of relaxation during domain coarsening increases with the
coefficient of the nonvariational term.Comment: 9 Pages, 8 Postscript Figures, 3 gif Figure
Low-Prandtl-number B\'enard-Marangoni convection in a vertical magnetic field
The effect of a homogeneous magnetic field on surface-tension-driven
B\'{e}nard convection is studied by means of direct numerical simulations. The
flow is computed in a rectangular domain with periodic horizontal boundary
conditions and the free-slip condition on the bottom wall using a
pseudospectral Fourier-Chebyshev discretization. Deformations of the free
surface are neglected. Two- and three-dimensional flows are computed for either
vanishing or small Prandtl number, which are typical of liquid metals. The main
focus of the paper is on a qualitative comparison of the flow states with the
non-magnetic case, and on the effects associated with the possible
near-cancellation of the nonlinear and pressure terms in the momentum equations
for two-dimensional rolls. In the three-dimensional case, the transition from a
stationary hexagonal pattern at the onset of convection to three-dimensional
time-dependent convection is explored by a series of simulations at zero
Prandtl number.Comment: 26 pages, 9 figure
Influence of through-flow on linear pattern formation properties in binary mixture convection
We investigate how a horizontal plane Poiseuille shear flow changes linear
convection properties in binary fluid layers heated from below. The full linear
field equations are solved with a shooting method for realistic top and bottom
boundary conditions. Through-flow induced changes of the bifurcation thresholds
(stability boundaries) for different types of convective solutions are deter-
mined in the control parameter space spanned by Rayleigh number, Soret coupling
(positive as well as negative), and through-flow Reynolds number. We elucidate
the through-flow induced lifting of the Hopf symmetry degeneracy of left and
right traveling waves in mixtures with negative Soret coupling. Finally we
determine with a saddle point analysis of the complex dispersion relation of
the field equations over the complex wave number plane the borders between
absolute and convective instabilities for different types of perturbations in
comparison with the appropriate Ginzburg-Landau amplitude equation
approximation. PACS:47.20.-k,47.20.Bp, 47.15.-x,47.54.+rComment: 19 pages, 15 Postscript figure
Convection in Binary Fluid Mixtures. II. Localized Traveling Waves. (Physical Review E, in press)
Nonlinear, spatially localized structures of traveling convection rolls are
investigated in quantitative detail as a function of Rayleigh number for two
different Soret coupling strengths (separation ratios) with Lewis and Prandtl
numbers characterizing ethanol-water mixtures. A finite-difference method was
used to solve the full hydrodynamic field equations numerically. Structure and
dynamics of these localized traveling waves (LTW) are dominated by the
concentration field. Like in the spatially extended convective states ( cf.
accompanying paper), the Soret-induced concentration variations strongly
influence, via density changes, the buoyancy forces that drive convection. The
spatio-temporal properties of this feed-back mechanism, involving boundary
layers and concentration plumes, show that LTW's are strongly nonlinear states.
Light intensity distributions are determined that can be observed in side-view
shadowgraphs. Detailed analyses of all fields are made using colour-coded
isoplots, among others. In the frame comoving with their drift velocity, LTW's
display a nontrivial spatio-temporal symmetry consisting of time-translation by
half an oscillation period combined with vertical reflection through the
horizontal midplane of the layer. A time-averaged concentration current is
driven by a phase difference between the waves of concentration and vertical
velocity in the bulk of the LTW state. The associated large-scale concentration
redistribution stabilizes the LTW and controls its drift velocity into the
quiescent fluid by generating a buoyancy-reducing concentration "barrier" ahead
of the leading LTW front. The selection of the width of the LTW's is
investigated and comparisons with experiments are presented.Comment: 18 pages and 6 figures as uuencoded Postscript file (using uufiles) 1
color figure as uuencoded Postscript file, a high resolution version of the
color figure (about 10MB) can be requested from [email protected] or
[email protected].: (Barten)present address: PSI, CH-5232 Villigen
PSI, Switzerlan
Planform selection in two-layer Benard-Marangoni convection
Benard-Marangoni convection in a system of two superimposed liquids is
investigated theoretically. Extending previous studies the complete
hydrodynamics of both layers is treated and buoyancy is consistently taken into
account. The planform selection problem between rolls, squares and hexagons is
investigated by explicitly calculating the coefficients of an appropriate
amplitude equation from the parameters of the fluids. The results are compared
with recent experiments on two-layer systems in which squares at onset have
been reported.Comment: 17 pages, 7 figures, oscillatory instability included, typos
corrected, references adde
Variation in the human soluble epoxide hydrolase gene and risk of restenosis after percutaneous coronary intervention
<p>Abstract</p> <p>Background</p> <p>Restenosis represents the major limiting factor for the long-term efficacy of percutaneous coronary intervention (PCI). Several genetic factors involved in the regulation of the vascular system have been described to play a role in the pathogenesis of restenosis. We investigated whether the <it>EPHX2 K55R </it>polymorphism, previously linked to significantly higher risk for coronary heart disease (CHD), was associated with the occurrence of restenosis after PCI. The association with incident CHD should have been confirmed and a potential correlation of the <it>EPHX2 K55R </it>variant to an increased risk of hypertension was analysed.</p> <p>Methods</p> <p>An overall cohort of 706 patients was studied: This cohort comprised of 435 CHD patients who had undergone successful PCI. Follow-up coronary angiography in all patients was performed 6 months after intervention. Another 271 patients in whom CHD had been excluded by coronary angiography served as controls. From each patient EDTA-blood was drawn at the baseline ward round. Genomic DNA was extracted from these samples and genotyping was performed by real-time PCR and subsequent melting curve analysis.</p> <p>Results</p> <p>In CHD patients 6 month follow-up coronary angiography revealed a restenosis rate of 29.4%, classified as late lumen loss as well as lumen re-narrowing ≥ 50%.</p> <p>Statistical analysis showed an equal genotype distribution in restenosis patients and non-restenosis patients (A/A 82.0% and A/G + G/G 18.0% versus A/A 82.1% and A/G + G/G 17.9%). Moreover, neither a significant difference in the genotype distribution of CHD patients and controls nor an association with increased risk of hypertension was found.</p> <p>Conclusion</p> <p>The results of the present study indicate that the <it>EPHX2 K55R </it>polymorphism is not associated with restenosis after PCI, with incidence of CHD, or with an increased risk of hypertension and therefore, can not serve as a predictor for risk of CHD or restenosis after PCI.</p
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