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Results for “Analog-Digital Conversion”

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At least 271 records · Page 15Linked to original sources
PubMed1990

In vitro pharmacologic separation of corneal endothelial migration and spreading responses.

Repair of corneal endothelial wounds involves two forms of cell translocation: (1) "migration," in which individual cells at the wound edge break contacts with neighboring cells and move as individuals into the wound defect, and (2) "spreading," in which cells within the confluent monolayer adjacent to the wound move as a group into the wound area. The authors combined morphometric analysis of Giemsa-stained cultures, phase-contrast video microscopy, and Rh-phalloidin staining of actin filaments to study the effects of epidermal growth factor (EGF) and indomethacin on the migratory and spreading responses to wounding using an in vitro wound-closure model which mimics the amitotic state and general behavior of human corneal endothelium. They found that EGF stimulated the migration of individual cells from the wound edge, induced cellular elongation, and promoted a diffuse distribution of actin filaments. Indomethacin promoted spreading of the confluent monolayer into the wound defect, induced enlargement and flattening of cells, and promoted the formation of long, thick actin stress fibers. These results provide evidence that the migration and spreading responses of corneal endothelial cells to wounding can be pharmacologically separated. The findings suggest that migration of individual cells during wound repair may result from an endogenous form of EGF-like stimulation and that the elongated shape associated with this form of translocation results, at least in part, from an EGF-like alteration in actin-filament organization. Spreading of the confluent monolayer to cover the wound defect may result from a decrease in cyclic adenosine monophosphate induced by a transient reduction in prostaglandin E2 synthesis. This form of translocation may result, in part, from enlargement and flattening of corneal endothelial cells secondary to an enhancement of actin stress-fiber formation.

Actins↗
PubMed1978

Computerization of three-channel thrombelastograph.

A small-size and low-cost microcomputer using an Intel 8080 micro-processer is employed to provide real-time data collection and reduction of a three-channel electronic-readout thrombelastograph (TEG). Computed values of significant clotting parameters are obtained instantly allowing for rapid analysis and monitoring of many patients. Computer hardware was designed to optimize signal sampling rates, processing time and storage.

Analog-Digital Conversion↗
PubMed1977

[Automatic analysis of gastrographies by means of optical digital equipment (author's transl)].

The present paper is concerned with problems of automatic analysis of radiograms, specially cinegastrographies. This study is connected with the utilisation of an interactive system including optical digitizer with its units of control and visualization. This system can explore the radiologic film in its current size of 30 X 40 cm. The particular interest of this application is extracting several parameters characterizing the size and the shape of the stomach. A middle axis can be extracted by computing, from this one a spatio-temporal diagram can be obtained. From this methodology of representation, several states of gastric motility could be characterized.

Analog-Digital Conversion↗
PubMedDate not supplied

[Simulator of cardiac activity signals].

Imitators of physiological signals are in need for production of electronic medical equipment and modeling the biological systems. The known imitators are rather intricate and incapable to control the output signal within a wide range. The imitator now offered allows to reproduce any signal that reflects the activity of a cardiovascular system under normal and pathologic conditions.

Analog-Digital Conversion↗
PubMedDate not supplied

[The role of digital storage in radiological studies based on fluoroscopic technics].

In recording radiological images obtained by fluoroscopic techniques on permanent support, digital storage, when compared with other methods, shows several interesting features, especially in order to reduce the X-ray dose and to allow for using economical hard copies. In the paper a system is described, for which it is possible to predict competitive cost in the near future; such system is based on a 512 X 512 X 6 bits digital memory, continuosly refreshed and on a software package oriented to handle radiological images. Examples of images referring to typical body segments (stomach, skull, chest) are reported.

Analog-Digital Conversion↗
PubMedDate not supplied

A comparison of gel-to-gel and skin measurements of electrode impedance.

Utilizing an automated test system, measurements of the 10-Hz impedance were made with electrode pairs joined gel-to-gel and electrode quartets on the skin of the backs of human volunteers. Two skin preparation procedures were examined. As a minimum skin preparation, the electrodes were applied to clean, dry skin from which body hair had been shaved if necessary. As a maximal preparation, the electrodes were applied after mild abrasion of the skin with fine emery cloth. Although the impedances measured for electrodes applied to mildly abraded skin correlated well with measurements made with electrodes of the same brand joined gel-to-gel, virtually no correlation was found if the electrodes were affixed to clean, dry skin.

Adult↗
PubMedDate not supplied

Automated measurement and frequency analysis of the pneumocardiogram.

The flow pneumocardiogram (PnCG), ie, measurement of cardiogenic gas movement in and out of the lung during apnea, was transduced by an in-line, high-gain pneumotachograph. A portion of the differentiated PnCG, the dPn/dt IJ wave, has been shown previously to correlate closely with left ventricular function. A simple analog device was designed and tested to measure the dPn/dt IJ amplitude on a practical beat-to-beat basis. Frequency-power spectral analysis showed the PnCG to be a low frequency phenomenon with the systolic component in the 9-to-10-Hz range. Appropriate band-pass filtering of the PnCG and its applicability as an intraoperative monitoring device are presented.

Analog-Digital Conversion↗