The design, fabrication, and characterization of a one-dimensional photonic crystal optical filter that has a relatively narrow, flat-topped passband within a wide stop band and small angular sensitivity is presented. The filter is based on a one-dimensional photonic crystal structure that has multiple defects, facilitating simultaneous minimization of the angular sensitivity and optimization o...

Few experimental and complementary theoretical studies have investigated high-frequency (>20 MHz) nonlinear responses from polymer-shelled ultrasound contrast agents. Three polymer agents with different shell properties were examined for their single-bubble backscatter when excited with a 40 MHz tone burst. Higher-order harmonic responses were observed for the three agents; however, their occur...

Because US plays a key role in the initial evaluation of hepatic hemangiomas, knowledge of the entire spectrum of US appearances of these tumors is important. Most hemangiomas have a distinctive US appearance, and even with those with atypical appearances on conventional gray-scale US, specific diagnoses can be made using pulse-inversion harmonic US with contrast agents. In this essay, we revie...

The purpose of this study was to investigate the effect of color contrast on luminance discrimination. Observers were required to indicate the more intense of two stimuli presented briefly in a surround. In some conditions the two stimuli were the same chromaticity as the surround, while in other conditions the stimuli differed in chromaticity from the surround. The luminance of the fixed test ...

A patch that alternates between two hues such as dark green and light blue looks greenish on a light gray surround and bluish on a dark gray surround ("flicker-augmented contrast"). Thus, when an edge alternates between two hues in the same location, the visual system selects the more salient hue-the one with the higher Michelson contrast. However, the afterimage is the same pink, driven by the...

J. Cataliotti and A. Gilchrist (1995) reported that, consistent with anchoring theory, the lightness of a black step in a reflectance staircase was not altered by moving a white step from a remote to an adjacent location. Recently, E. Economou, S. Zdravkovic, and A. Gilchrist (2007) reported data supporting three additional predictions of the anchoring model (A. Gilchrist et al., 1999): 1) equi...

Large health care systems with varied hospital cultures, environments, and practices are continually challenged to provide safer and higher quality patient care. The authors describe their experience implementing uniform procedures for computed tomographic contrast media administration and the impact that standardization of these practices had on patient safety at a large integrated health care...