Engineering topics
Karp, S.
Publications and source records attributed to Karp, S..
Altering the cellular mechanical force balance results in integrated changes in cell, cytoskeletal and nuclear shape
Studies were carried out with capillary endothelial cells cultured on fibronectin (FN)-coated dishes in order to analyze the mechanism of cell and nuclear shape control by extracellular matrix (ECM). To examine the role of the cytoskeleton in shape determination independent of changes in transmembrane osmotic pressure, membranes of adherent cells were permeabilized with saponin (25 micrograms/ml) using a buffer that maintains the functional integrity of contractile microfilaments. Real-time videomicroscopic studies revealed that addition of 250 microM ATP resulted in time-dependent retraction and rounding of permeabilized cells and nuclei in a manner similar to that observed in intact living cells following detachment using trypsin-EDTA. Computerized image analysis confirmed that permeabilized cells remained essentially rigid in the absence of ATP and that retraction was stimulated in a dose-dependent manner as the concentration of ATP was raised from 10 to 250 microM. Maximal rounding occurred by 30 min with projected cell and nuclear areas being reduced by 69 and 41%, respectively. ATP-induced rounding was also accompanied by a redistribution of microfilaments resulting in formation of a dense net of F-actin surrounding retracted nuclei. Importantly, ATP-stimulated changes in cell, cytoskeletal, and nuclear form were prevented in permeabilized cells using a synthetic myosin peptide (IRICRKG) that has been previously shown to inhibit actomyosin filament sliding in muscle. In contrast, both the rate and extent of cell and nuclear rounding were increased in permeabilized cells exposed to ATP when the soluble FN peptide, GRGDSP, was used to dislodge immobilized FN from cell surface integrin receptors.(ABSTRACT TRUNCATED AT 250 WORDS).
Approximations for lognormally fading optical signals
Photoelectron count of lognormally fading optical signal, discussing noncentral chi square random variable approximation
Photon counting - A problem in classical noise theory
Quantum detector with impinging EM field, discussing photoelectron counting distribution and signal with white noise
Communication theory for the free space optical channel Interim technical report
Quantum detectors, noise mechanisms, and application to optical communication theory
Photon counting - A problem in classical noise theory
Photoelectron distribution in electromagnetic field impinging on quantum detector
On the representation of a continuous stochastic intensity by Poisson shot noise
Poisson shot noise process relationship with continuous stochastic intensity as sample function
The design of a pulse-position modulated optical communication system
Narrow width pulse-position modulated optical communication system design, determining performance in terms of error probability and information rates
Comments on optical heterodyne detection
Optical heterodyne quantum detector response, calculating signal to noise ratios
Communication efficiencey of quantum systems
Quantum communication systems performance evaluated by communication efficiency parameter
M-ary Poisson detection and optical communications.
M-ary detection for optical communication investigated for maximum likelihood detection of one of M Poisson processes in background noise
Optical space communication
Results of workshop on optical communication systems for space applications
The design of a Pulse Position Modulated /PPM/ optical communication system
Design of pulse position modulation optical communication system
Error probabilities for maximum likelihood detection of M-ary Poisson processes in Poisson noise
Error probabilities for maximum signal detection in presence of Poisson noise
Radiation models using discrete radiator ensembles.
Radiation models using discrete radiator ensembles having applications to analysis of forward and backscatter from rough surfaces, clutter and chaff models, etc
M-ary Poisson Detection and Optical Communications
Optical communications - maximum likelihood detection of M-ary Poisson processes in background of additive Poisson noise
Observations of CO sub 2 laser radiation with an infrared image converter.
Carbon dioxide laser radiation characteristics by visual observation using closed circuit TV system with IR image converter