Calcium (Ca2+) plays a central role in the contraction of the heart. It is the bi-directional link between electrical excitation of the heart and contraction. Electrical excitation initiates Ca2+influx across the sarcolemma and T-tubular membrane that triggered calcium release from the sarcoplasmic reticulum. Ca2+sparks are the elementary events of calcium release from the sarcoplasmic reticulu...

D. S. Lake, A. Manduca, Y. Mariappan, R. L. Ehman Mayo Clinic College of Medicine, Rochester, MN, United States Introduction Magnetic resonance elastography (MRE) is a phase contrast based MRI imaging technique that can directly visualize and quantitatively measure propagating acoustic strain waves in tissue-like materials subjected to harmonic mechanical excitation [1]. The data acquired allow...

We present measurements of iso-frequency dispersion surfaces of light scattered from metallic micro-gratings with different periods. The dispersion surfaces, obtained using an infinity-corrected microscope objective, exhibit maxima attributed to diffracted orders as they become evanescent and pronounced minima due to the resonant excitation of surface plasmon polaritons (SPPs). We have also mea...

Motion vision provides essential cues for navigation and course control as well as for mate, prey, or predator detection. Consequently, neurons responding to visual motion in a direction-selective way are found in almost all species that see. However, directional information is not explicitly encoded at the level of a single photoreceptor. Rather, it has to be computed from the spatio-temporal ...

The smallness of natural molecules and atoms with respect to the wavelength of light imposes severe limits on the nature of their optical response. For example, the well-known argument of Landau and Lifshitz and its recent extensions that include chiral molecules show that the electric dipole response dominates over the magneto-electric (bianisotropic) and an even smaller magnetic dipole optica...

We analyze a single photon source consisting of an InAs quantum dot coupled to a directional-emission photonic crystal (PC) cavity implemented in GaAs. On resonance, the dot's lifetime is reduced by more than 10 times, to 45 ps. Compared to the standard three-hole defect cavity, the perturbed PC cavity design improves the collection efficiency into an objective lens (NA = 0.75) by factor 4.5, a...

Multidirectional selective plane illumination microscopy (mSPIM) reduces absorption and scattering artifacts and provides an evenly illuminated focal plane. mSPIM solves two common problems in light-sheet-based imaging techniques: The shadowing in the excitation path due to absorption in the specimen is eliminated by pivoting the light sheet; the spread of the light sheet by scattering in the s...

Microstreaming generated from oscillating microbubbles has great potential in microfluidic applications for localized flow control. In this study, we explore the use of teardrop-shaped cavities for trapping microbubbles. Upon acoustic actuation, these microbubbles confined in teardrop cavities can be utilized to generate a directional microstreaming flow. We further show that by altering the ac...

MXenes are two-dimensional materials with a rich set of chemical and electromagnetic properties, the latter including saturable absorption intense surface plasmon resonances. To fully harness functionality for applications in optics, electronics, sensing, it is important to understand interaction light on atomic femtosecond dimensions. Here, we use ultrafast electron diffraction high-resolution...

We report here a general theory describing photoelectron transportation dynamics in GaAs semiconductor photocathodes. Gradient doping is incorporated the model through inclusion of directional carrier drift. The time-evolution electron concentration active layer upon injection an excitation pulse solved both numerically and analytically. predictions are compared with experiments via carrier-ind...