RESUMO
A universal, torque-mixing method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by magnetic induction, the transverse component of a precessing dipole moment can be measured in sensitive broadband spectroscopy, here using a resonant mechanical torque sensor. Unlike induction, the torque amplitude allows equilibrium magnetic properties to be monitored simultaneously with the spin dynamics. Comprehensive electron spin resonance spectra of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature reveal assisted switching between magnetization states and mode-dependent spin resonance interactions with nanoscale surface imperfections. The rich detail allows analysis of even complex three-dimensional spin textures. The flexibility of microelectromechanical and optomechanical devices combined with broad generality and capabilities of torque-mixing magnetic resonance spectroscopy offers great opportunities for development of integrated devices.
RESUMO
Management and prognosis of acute coronary syndromes may be influenced by the availability of catheterization facilities at admitting hospitals. Treatment effects of tirofiban were examined in a Canadian cohort of 834 patients enrolled in the Canadian Platelet Receptor Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms (PRISM-PLUS) trial according to admission into hospitals without (n = 322) or with catheterization facilities (n = 512). Hospital transfers for cardiac catheterization were facilitated using preexisting networks accelerated for the purposes of the protocol. In hospitals without facilities, the relative risks for occurrence of death, infarction, or refractory ischemia among patients receiving tirofiban plus heparin compared with heparin alone were 0.52 at 7 days (p = 0.02), 0.59 at 30 days (p = 0.03), and 0.70 at 180 days (p = 0.09); and for death or infarction, 0.32 (p = 0.02), 0.46 (p = 0.04,) and 0.51 (p = 0.03), respectively. Benefit was seen regardless of transfer status, with no statistically significant interaction between treatment, hospital type, and catheterization for any end point at any time point. The incidence of Thrombolysis In Infarction defined major bleeding with respect to therapy was not significantly different between hospital types. Thus, upstream treatment with tirofiban plus heparin confers clinical benefits in unstable angina and/or non-ST-segment elevation infarction patients regardless of whether initial presentation is to a hospital without catheterization facilities or to a hospital with such facilities.
