Toward automated analysis of particle holograms

A preliminary study of approaches for extracting and analyzing data from particle holograms is discussed. It concludes that: (1) for thin spherical particles, out-of-focus methods are optimum; (2) for thin nonspherical particles, out-of-focus methods are useful but must be supplemented by in-focus methods; (3) a complex method of projection and back projection can remove out-of-focus data for deep particles

Automatic holographic droplet analysis for liquid fuel sprays

The basic scheme for automated holographic analysis involves an optical system for reconstruction of the three dimensional real image of the droplet field, a spatial scanning system to transport a digitizing X-y image sensor through the real image, and processing algorithms for droplet recognition which establish the droplet sizes and positions. The hardware for system demonstrated includes the expanded and collimated beam from a 5 mW helium-neon laser for hologram reconstruction, an imaging lens for magnification of the real image field, and a video camera and digitizer providing 512-by-512 pixel resolution with 8-bit digitization. A mechanical stage is used to scan the hologram in three dimensional space, maintaining constant image magnification. A test droplet hologram is used for development and testing of the image processing algorithms

Optical implementation of systolic array processing

Algorithms for matrix vector multiplication are implemented using acousto-optic cells for multiplication and input data transfer and using charge coupled devices detector arrays for accumulation and output of the results. No two dimensional matrix mask is required; matrix changes are implemented electronically. A system for multiplying a 50 component nonnegative real vector by a 50 by 50 nonnegative real matrix is described. Modifications for bipolar real and complex valued processing are possible, as are extensions to matrix-matrix multiplication and multiplication of a vector by multiple matrices

STUDIES ON PROTEIN UPTAKE BY ISOLATED TUMOR CELLS : I. Electron Microscopic Evidence of Ferritin Uptake by Ehrlich Ascites Tumor Cells

Ferritin, added to the incubation medium of ascites tumor cells, was used as an electron microscopic marker to study the uptake of large protein molecules by morphologically intact cells. A definite uptake could be detected after 1 hour of incubation in Tyrode bicarbonate solution containing 0.04 to 13.3 mg ferritin/ml. Ferritin was found in a variety of membrane-surrounded structures, suggesting that pinocytesis and related membrane movements are occurring under physiological conditions and can account for the penetration of intact macromolecules into isolated tumor cells. Supplementation of the medium with serum albumin (33 mg/ml) increased the average amount of ferritin per cell and per pinocytotic structure. Ferritin was strongly adsorbed by fragments of lysed cells, which were readily taken up by intact cells. Besides its role as carrier, this debris appeared to stimulate membrane movements. Only rare examples were found to suggest the release of ferritin from the pinocytotic structures into the cytoplasm. Thus, the disintegration of such structures cannot be considered an obvious step towards a rapid metabolic utilization of protein by the cell. Particles of colloidal gold presented to the cell under the same conditions were not taken up to any significant extent, thus providing good evidence for a selective ingestion of particles of comparable sizes

STUDIES ON PROTEIN UPTAKE BY ISOLATED TUMOR CELLS : II. Quantitative Data on the Adsorption and Uptake of I131-Serum Albumin by Ehrlich Ascites Tumor Cells

Surface adsorption is studied in some detail because it is believed to be a major artifact in measurements of protein uptake by mammalian cells. Adsorption increases linearly with the I131-albumin concentration between 0.001 and 300 mg/ml. After short exposure to 300 mg/ml and two cell washings, the adsorption amounts to 38 mg albumin per gm cell proteins. Further washings remove 80 per cent of this value, leaving a small irreversibly bound residue. At equilibrium, adsorbed albumin can be labeled by a simple albumin exchange. This labeling reaches a steady state within seconds and stays at constant level over 30 minutes. Significant increases above this initial level are measured over periods of 2 hours. In our experimental conditions these increases can be considered due to albumin uptake. This uptake rises linearly with the albumin concentration between 0.5 and 50.0 mg/ml, and reaches 0.2 mg/gm cell protein or 4 x 105 molecules per cell. Compared to the incorporation of free amino acids in similar conditions, this value does not appear to contribute significantly to the N-metabolism of the tumor cells. Adsorption was generally greater than uptake. Both processes are linear functions of the same variable over the whole range of concentration tested. It is suggested that albumin is taken up by pinocytosis

A method to construct refracting profiles

We propose an original method for determining suitable refracting profiles between two media to solve two related problems: to produce a given wave front from a single point source after refraction at the refracting profile, and to focus a given wave front in a fixed point. These profiles are obtained as envelopes of specific families of Cartesian ovals. We study the singularities of these profiles and give a method to construct them from the data of the associated caustic.Comment: 12 pages, 5 figure

Photoluminescence dispersion as a probe of structural inhomogeneity in silica

We report time-resolved photoluminescence spectra of point defects in amorphous silicon dioxide (silica), in particular the decay kinetics of the emission signals of extrinsic Oxygen Deficient Centres of the second type from singlet and directly-excited triplet states are measured and used as a probe of structural inhomogeneity. Luminescence activity in sapphire ($\alpha$-Al$_2$O$_3$) is studied as well and used as a model system to compare the optical properties of defects in silica with those of defects embedded in a crystalline matrix. Only for defects in silica, we observe a variation of the decay lifetimes with emission energy and a time dependence of the first moment of the emission bands. These features are analyzed within a theoretical model with explicit hypothesis about the effect introduced by the disorder of vitreous systems. Separate estimations of the homogenous and inhomogeneous contributions to the measured emission linewidth are obtained: it is found that inhomogeneous effects strongly condition both the triplet and singlet luminescence activities of oxygen deficient centres in silica, although the degree of inhomogeneity of the triplet emission turns out to be lower than that of the singlet emission. Inhomogeneous effects appear to be negligible in sapphire