RESUMEN
Z-scan is a well-established technique used to measure the nonlinear refractive index and absorption coefficient of thin and transparent materials. The method requires the displacement of the sample along the focus of a laser beam. Therefore, the Z-scan is not suitable for experiments where the sample cannot be axially translated. Here, we explore a deformable mirror to create controllable defocus aberrations, translating the focus of the beam through the sample, alternatively to the sample displacement. The technique is based on time behavior analysis of the light beam transmitted by the nonlinear sample, at different defocus configurations. The method is validated by measuring reference samples (CS2 and SiO2) and comparing them with the conventional Z-scan technique.
RESUMEN
OBJECTIVES: To determine levels of vascular cellular adhesion molecule (VCAM)-1 and endothelin (ET)-1 in patients with stroke. DESIGN AND METHODS: Thirty-four patients were prospectively studied. Plasma levels of VCAM-1 and ET-1 were measured by ELISA within 72 h of the event, at 7 and 90 days. RESULTS: Levels of VCAM-1 increased overtime, whereas ET-1 values were initially and persistently elevated. CONCLUSIONS: Increased circulating levels of VCAM-1 and ET-1 are present during stroke.