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Biomedical subjects

M S Markov

Publications and source records attributed to M S Markov.

5 recordsLinked to original sources
PubMed1993

Real-time algorithm for retinal tracking.

Conventional retinal laser photocoagulation is presently performed by an ophthalmologist manually aiming a low-power laser beam at a desired site and firing a high-power laser for a preselected interval of time. To automate this process a retinal tracker must acquire a target, track small saccades, and identify loss of track during a large saccade. The authors successfully implemented a real-time algorithm that used a simple computer, video digitizing card, low light video camera, and fundus camera to perform rudimentary tracking on a photograph of a retina undergoing smooth circular motion. The algorithm tracked speeds up to 5 Hz, or 27 degrees/s, which equated to the retina moving in a 525 microns diameter circle.

Algorithms↗
PubMedDate not supplied

Biophysical estimation of the environmental importance of electromagnetic fields.

The rapid development of science and technology exposes living organisms to a wide range of electromagnetic fields. Some life-style and occupational conditions are associated with a level of electromagnetic fields higher than average. A series of epidemiological studies has raised concern about possible cancer risk of electromagnetic fields generated by power lines and electrical appliances. In contrast, hundreds of thousands of patients world-wide have been cured by use of electromagnetic fields. Biological effects of low-level electromagnetic radiation have become the focus of a number of studies. However, there are not enough basic scientific data related to mechanisms of action of electromagnetic fields. This paper proposes a biophysical approach to the estimation of the environmental importance of electromagnetic fields. The methods of collecting data, dosimetry, possible mechanisms of action and open problems are discussed in this review.

Electric Power Supplies↗
PubMedDate not supplied

Bioeffects of weak electromagnetic fields.

Time varying magnetic fields are most often employed for therapeutic purposes and are present in environmental sources. In order for an electromagnetic field bioeffect to be possible, the signal parameters should not only satisfy the dielectric properties of the target, but also induce sufficient voltage to be detectable above thermal noise. The problem of the sensitivity of living cells and tissues is discussed in relation to signal/noise ratio at the target site. Some biophysical models for interactions of weak electromagnetic fields with biological systems are summarized. Cell studies and therapeutic application of electric and magnetic fields indicate that weak electromagnetic fields can have a profound effect on a large variety of biological systems.

Animals↗
PubMedDate not supplied

Use of lectins as indicators for magnetic field action on erythrocyte membranes.

The effects of magnetic fields on biological membranes in general and on the red blood cell membrane in particular have been studied intensively in the last two decades. A variety of methods for evaluation of magnetic field action on the structure and function of biological membranes has been used. It has been suggested /1/ that the cell membrane can be considered as one of the primary targets affected by magnetic field exposure.

Electric Impedance↗