Contributions of mechanical loading and hormonal changes to eccentric hypertrophy during volume overload: a Bayesian analysis using logic-based network models.

Primary mitral regurgitation (MR) is a pathology that alters mechanical loading on the left ventricle, triggers an array of compensatory neurohormonal responses, and induces a distinctive ventricular remodeling response known as eccentric hypertrophy. Drug therapies may alleviate symptoms, but only mitral valve repair or replacement can provide significant recovery of cardiac function and dimensions. Questions remain about the optimal timing of surgery, with 20% of patients developing systolic dysfunction post-operatively despite being treated according to the current guidelines.

A medium composition containing normal resting glucose that supports differentiation of primary human airway cells.

Primary cells isolated from the human respiratory tract are the state-of-the-art for in vitro airway epithelial cell research. Airway cell isolates require media that support expansion of cells in a basal state to maintain the capacity for differentiation as well as proper cellular function. By contrast, airway cell differentiation at an air-liquid interface (ALI) requires a distinct medium formulation that typically contains high levels of glucose.

Ellipse fitting for interferometry. Part 2: experimental realization.

Extracting phase and amplitude information from the quadrature signals of an optical interferometer is an essential first step in any measurement. Where these signals are displayed as a Lissajous figure, the primary limitation to accuracy is determined by the goodness-of-fit to the ellipse, which is especially problematic for ellipses with high ellipticity. In a companion paper by Collett and Tee [J.

White-light ellipsometer with geometric phase shifter.

We describe a simple spectroscopic ellipsometer that uses a geometric phase shifter and a white-light source to generate a small number of phase-stepped intensities I(λ), which are recorded by a spectrometer. The ellipsometric angles ψ and Δ are easily calculated from these intensities at each wavelength simultaneously. We show that errors in Δ due to the nonideal behavior of the achromatic quarter-wave plate in the phase shifter can be made small by suitably adjusting the azimuth of the linearly polarized light incident on the sample.

Spectroscopic ellipsometer based on direct measurement of polarization ellipticity.

A polarizer-sample-Wollaston prism analyzer ellipsometer is described in which the ellipsometric angles ψ and Δ are determined by direct measurement of the elliptically polarized light reflected from the sample. With the Wollaston prism initially set to transmit p- and s-polarized light, the azimuthal angle P of the polarizer is adjusted until the two beams have equal intensity. This condition yields ψ=±P and ensures that the reflected elliptically polarized light has an azimuthal angle of ±45° and maximum ellipticity.

Spectroscopic null ellipsometer using a variable retarder.

We describe a polarizer-compensator-sample-analyzer (PCSA) null ellipsometer in which a variable retarder is used as the compensator and either the polarizer or the analyzer is held at a fixed azimuthal angle. Ellipsometric angles ψ and Δ are determined directly from the azimuth of the rotating component and the compensator delay, respectively. A Soleil-Babinet compensator with quartz plates is used as the variable delay element and the delay at any wavelength is calculated from the independently measured delay at 632.

Variable angle of incidence spectroscopic autocollimating ellipsometer.

We present a spectroscopic, autocollimating ellipsometer capable of operating at arbitrary angles of incidence. Linearly polarized light incident on a sample is circularly polarized on reflection, ensuring that the retroreflected beam is orthogonal to the input polarization state. In order to achieve this at arbitrary angles of incidence, a Soleil-Babinet compensator (SBC) is introduced with its fast axis fixed horizontally.

Automatic null ellipsometry with an interferometer.

A new approach to automatic null ellipsometry is described in which the analyzer of a traditional polarizer compensator sample analyzer (PCSA) null ellipsometer is replaced with a heterodyne Michelson interferometer. One arm of this interferometer is modified such that it produces a fixed, linearly polarized reference beam, irrespective of the input polarization state. This beam is recombined interferometrically with the measurement beam and spatially separated into its p and s polarizations.

Interferometric ellipsometer.

We describe an interferometric ellipsometer that, in contrast to previous designs, requires a single reflection from a sample surface so that tanpsi and Delta are measured directly. A reference beam is created in one arm of a modified Mach-Zehnder interferometer such that the p and s polarizations have a common phase and fixed relative amplitude, irrespective of the sample. This beam is combined interferometrically with the measurement beam.

Ellipsometry with polarisation-entangled photons.

Polarisation-entangled photon pairs from a two crystal, type-I spontaneous parametric down conversion source are used to make accurate measurements of the ellipsometric angles of a silicon dioxide film on silicon and of internal and external reflection from BK7 glass. Since our source produces an entangled state with some mixture, a novel technique based on quantum tomography was developed to estimate the components of the density matrix for the state before and after reflection from the samples. The ellipsometric angles are readily calculated from these components and experimental measurements made on the samples were found to be in good agreement with their expected values.

Interferometric ellipsometer with wavelength-modulated laser diode source.

An interferometric ellipsometer, with no moving parts and an inexpensive laser diode source, is demonstrated. Temporal fringes are produced by a small modulation of the laser diode bias current and unbalanced arms in the interferometer. Fringe analysis algorithms are developed, and accurate measurements of the optical properties of a number of samples are made.