A cell-based high-throughput assay system reveals modulation of oxidative and nonoxidative glucose metabolism due to commonly used organic solvents.

A 96-well format screening system was generated to quantify changes in nonoxidative glucose metabolism and oxidative pyruvate metabolism. D-Glucose uptake from the supernatant media was quantified by the glucose oxidase method, and L-lactate production of cells was quantified by the lactate dehydrogenase method applied on supernatant media. Mitochondrial membrane potential was quantified using tetramethylrhodamine methyl ester (TMRM) fluorescence, and reactive oxygen species (ROS) formation was determined by quantification of dihydrodichlorofluorescein fluorescence. Adenosine triphosphate (ATP) content of myocytes was determined using the luciferin reaction, and cellular respiration was quantified using commercially available, precoated microtiter plates. These six assays were used to determine the putative influence of organic solvents, namely dimethyl sulfoxide (DMSO), ethanol, methanol, and N-methylpyrrolidone (NMP) at concentrations of 0.01, 0.1, 1.0, and 5.0% (vol/vol), respectively, on glucose and pyruvate metabolism after 4 and 24 hours. In summary, all solvents induced significant changes in regard to one or several of the parameters evaluated, affecting cellular glucose uptake, glycolysis, mitochondrial metabolism, or oxidative phosphorylation. Accordingly, this comprehensive HTS evaluation should enable researchers to choose specific organic solvents on a rational basis to avoid nonspecific effects in cultured cells and tissue culture based experimental setups.

Single-shot compressive spectral imaging with a dual-disperser architecture.

This paper describes a single-shot spectral imaging approach based on the concept of compressive sensing. The primary features of the system design are two dispersive elements, arranged in opposition and surrounding a binary-valued aperture code. In contrast to thin-film approaches to spectral filtering, this structure results in easily-controllable, spatially-varying, spectral filter functions with narrow features. Measurement of the input scene through these filters is equivalent to projective measurement in the spectral domain, and hence can be treated with the compressive sensing frameworks recently developed by a number of groups. We present a reconstruction framework and demonstrate its application to experimental data.

Measurement and data-processing approach for estimating the spatial statistics of turbulence-induced index of refraction fluctuations in the upper atmosphere.

We present a method of data reduction and analysis that has been developed for a novel experiment to measure the spatial statistics of atmospheric turbulence in the tropopause. We took measurements of temperature at 15 points on a hexagonal grid for altitudes from 12,000 to 18,000 m while suspended from a balloon performing a controlled descent. From the temperature data we estimate the index of refraction and study the spatial statistics of the turbulence-induced index of refraction fluctuations. We present and evaluate the performance of a processing approach to estimate the parameters of isotropic models for the spatial power spectrum of the turbulence. In addition to examining the parameters of the von Kármán spectrum, we have allowed the so-called power law to be a parameter in the estimation algorithm. A maximum-likelihood-based approach is used to estimate the turbulence parameters from the measurements. Simulation results presented here show that, in the presence of the anticipated levels of measurement noise, this approach allows turbulence parameters to be estimated with good accuracy, with the exception of the inner scale.

Joint processing of hartmann sensor and conventional image measurements to estimate large aberrations: theory and experimental results.

We report experimental results for what we believe to be a new technique for estimating aberrations that extends the strength of an aberration that may be sensed with Hartmann sensor technology by means of an algorithm that processes both a Hartmann sensor image and a conventional image formed with the same aberration. We find that the theory and the experiment match well within the experimental error and that strong defocus aberrations can be accurately sensed with this technique.

Algorithm to increase the largest aberration that can be reconstructed from Hartmann sensor measurements.

Conventional Hartmann sensor processing relies on locating the centroid of the image that is formed behind each element of a lenslet array. These centroid locations are used for computing the local gradient of the incident aberration, from which the phase of the incident wave front is calculated. The largest aberration that can reliably be sensed in a conventional Hartmann sensor must have a local gradient small enough that the spot formed by each lenslet is confined to the area behind the lenslet: If the local gradient is larger, spots form under nearby lenslets, causing a form of cross talk between the wave-front sensor channels. We describe a wave-front reconstruction algorithm that processes the whole image measured by a Hartmann sensor and a conventional image that is formed by use of the incident aberration. We show that this algorithm can accurately estimate aberrations for cases in which the aberration is strong enough to cause many of the images formed by individual lenslets to fall outside the local region of the Hartmann sensor detector plane defined by the edges of a lenslet.

Combined serum amylase and lipase determinations for diagnosis of suspected acute pancreatitis.

Serum amylase and lipase measurements are often used to diagnose acute pancreatitis. This study addresses the question of whether it is advantageous to order serum amylase and lipase tests simultaneously. We evaluated performance of the two tests separately and in combination through a retrospective study of patients for whom both amylase and lipase determinations were ordered. Initial analysis of test performance was conducted with a uniformly applied criterion based on determination of optimal sensitivity-specificity pairs. Individual tests and combinations of tests, including the "AND" and "OR" rules and discriminant functions, were examined. Only the discriminant approach demonstrated better performance than the lipase test alone. This finding was subsequently confirmed by logistic regression analysis. We conclude that ordering both tests simultaneously can be advantageous in diagnosing acute pancreatitis when a bivariate approach is used; however, this must be weighed against the difficulties associated with clinical implementation of such approaches.

Hubble Space Telescope characterized by using phase-retrieval algorithms.

We describe several results characterizing the Hubble Space Telescope from measured point spread functions by using phase-retrieval algorithms. The Cramer-Rao lower bounds show that point spread functions taken well out of focus result in smaller errors when aberrations are estimated and that, for those images, photon noise is not a limiting factor. Reconstruction experiments with both simulated and real data show that the calculation of wave-front propagation by the retrieval algorithms must be performed with a multiple-plane propagation rather than a simple fast Fourier transform to ensure the high accuracy required. Pupil reconstruction was performed and indicates a misalignment of the optical axis of a camera relay telescope relative to the main telescope. After we accounted for measured spherical aberration in the relay telescope, our estimate of the conic constant of the primary mirror of the HST was - 1.0144.

Three-dimensional, fine-resolution imaging using laser frequency diversity.

Experimental results obtained using a fine-resolution, three-dimensional imaging method are presented. The method consists of flood illuminating an extended object with a laser beam and recording the scattered light as the laser frequency is varied. An image is recovered by three-dimensional Fourier transformation of the recorded data. For the results presented here, a tunable dye-laser source is used, and the obtained range resolution is 287 microm.