Safety of short-term dual antiplatelet therapy after drug-eluting stents:An updated meta-analysis with direct and adjusted indirect comparison of randomized control trials

Background: Duration of dual antiplatelet therapy (DAPT) following drug-eluting stents (DES) remains controversial and is a topic of ongoing research. Methods: Direct and adjusted indirect comparisons of all the recent randomized control trials (RCTs) were performed to evaluate the safety of short-term versus long-term DAPT following DES. Results: 8 RCTs were identified and 7 (16,318 subjects) were included. 4 groups of 3 vs 12 months, 6 vs 12 months, 6 vs 24 months and 12 vs 24 months of DAPT were used for direct comparison. There was no significant difference in stent thrombosis, myocardial infarction (MI), stroke and revascularization, cardiovascular and all-cause mortality between the different durations in all 4 groups. Pooling trials of 3–6 months of DAPT against 12 months, we found a significant reduction in the risk of total bleeding (RR 0.61, 95% CI 0.43–0.87). Adjusted indirect comparison between 3 vs 6 months, 3 vs 24 months and 6 vs 24 month duration of DAPT showed no significant differences in risk of death or MI, or revascularization between 3 or 6 months and 24 months. However, 24 months of DAPT was associated with significantly more bleeding than 3 or 6 months. Conclusions: 3 to 6 months of DAPT following second generation DES and above is safe with no increased risk of thrombotic complications and mortality, and lower bleeding risk. However a tailored approach may be more appropriate for high-risk patients. Keywords: Percutaneous coronary intervention; Drug-eluting stent; Acute coronary syndrome; Dual antiplatelet treatment; Duration of therap

First-Order Vortex Lattice Melting and Magnetization of YBa2_2Cu3_3O$_{7-\delta}

We present the first non-mean-field calculation of the magnetization $M(T)$ of YBa$_2$Cu$_3$O$_{7-\delta}$ both above and below the flux-lattice melting temperature $T_m(H)$. The results are in good agreement with experiment as a function of transverse applied field $H$. The effects of fluctuations in both order parameter $\psi({\bf r})$ and magnetic induction $B$ are included in the Ginzburg-Landau free energy functional: $\psi({\bf r})$ fluctuates within the lowest Landau level in each layer, while $B$ fluctuates uniformly according to the appropriate Boltzmann factor. The second derivative $(\partial^2 M/\partial T^2)_H$ is predicted to be negative throughout the vortex liquid state and positive in the solid state. The discontinuities in entropy and magnetization at melting are calculated to be $\sim 0.034\, k_B$ per flux line per layer and $\sim 0.0014$~emu~cm$^{-3}$ at a field of 50 kOe.Comment: 11 pages, 4 PostScript figures in one uuencoded fil

Spatial Distribution of Competing Ions around DNA in Solution

The competition of monovalent and divalent cations for proximity to negatively charged DNA is of biological importance and can provide strong constraints for theoretical treatments of polyelectrolytes. Resonant x-ray scattering experiments have allowed us to monitor the number and distribution of each cation in a mixed ion cloud around DNA. These measurements provide experimental evidence to support a general theoretical prediction: the normalized distribution of each ion around polyelectrolytes remains constant when ions are mixed at different ratios. In addition, the amplitudes of the scattering signals throughout the competition provide a measurement of the surface concentration parameter that predicts the competition behavior of these cations. The data suggest that ion size needs to be taken into account in applying Poisson-Boltzmann treatments to polyelectrolytes such as DNA

First order phase transition of the vortex lattice in twinned YBa2Cu3O7 single crystals in tilted magnetic fields

We present an exhaustive analysis of transport measurements performed in twinned YBa2Cu3O7 single crystals which stablishes that the vortex solid-liquid transition is first order when the magnetic field H is applied at an angle theta away from the direction of the twin planes. We show that the resistive transitions are hysteretic and the V-I curves are non-linear, displaying a characteristic s-shape at the melting line Hm(T), which scales as epsilon(theta)Hm(T,theta). These features are gradually lost when the critical point H*(theta) is approached. Above H*(theta) the V-I characteristics show a linear response in the experimentally accessible V-I window, and the transition becomes reversible. Finally we show that the first order phase transition takes place between a highly correlated vortex liquid in the field direction and a solid state of unknown symmetry. As a consequence, the available data support the scenario for a vortex-line melting rather than a vortex sublimation as recently suggested [T.Sasagawa et al. PRL 80, 4297 (1998)].Comment: 10 pages, 8 figures, submitted to PR