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Biomedical subjects

M V Frolov

Publications and source records attributed to M V Frolov.

At least 37 records · Page 2Linked to original sources
PubMed1994

Cluster of cytochrome P450 genes on the X chromosome of Drosophila melanogaster.

A new cytochrome P450 gene was found within the wap1-prune genetic region of the Drosophila melanogaster X chromosome. It encodes a putative cytochrome P450 of subfamily 4D and has been designated CYP4D2. CYP4D2 has a complex exon-intron structure. Both the heme-binding motif and a region diagnostic for family 4 are not interrupted by introns. CYP4D2 lies 20 kb proximal to the previously described CYP4D1 gene (Gandhi et al., 1992). In addition to CYP4D1 and CYP4D2, two other DNA fragments homologous to P450 genes are detected within the wap1-prune region.

Amino Acid Sequence↗
PubMed1993

[Region of the prune locus in Drosophila melanogaster is transcriptionally saturated].

Using Northern analysis three transcription areas are detected in the gene prune region from which three different mRNAs 1.8, 1.75 and 1.0 kb in length transcribe. Corresponded cDNAs are cloned. Only 1.8 kb mRNA is shown to be changed in size and quantity in the case of the pn1 and pn3 mutations. This mRNA seems to be a gene prune transcript. From the analysis of the portion of cDNA c1.1 nucleotide sequence corresponded 1.75 kb mRNA follows that its putative amino acid product contains a heme-binding site which is characterized for P450 cytochrome superfamily. On the basis of presented results and published data by Teng et al [1] it may be concluded that at least five different mRNAs transcribe in the gene prune region in area spanning about 10 kb.

Amino Acid Sequence↗
PubMed1993

[Transcription of the prune gene during a position effect of the mosaic type in Drosophila melanogaster].

Analysis of transcription of the gene prune being undergone position effect variegation in the inversion In(1LR)pn2a is presented. Using Northern hydridization with following densitometric analysis of blots it was shown that the quantity of the prune mRNA is decreased 1.8 +/- 0.4 times in comparison with normal. Transcripts differing from wild type sizes are not detected. On the basis of the results obtained of inactivation propagation in the case of the position effect.

Animals↗
PubMed1991

The development of pursuit tracking skills.

This article examines the development of the visual-motor skill of pursuit tracking. Parameters studied include tracking error and emotional tension, as manifested in heart rate and strength of grip exerted on the control handle used in the task. A specially developed device converted grip strength into an electrical signal suitable for analysis. Grip strength proved to be a more sensitive indicator of development and level of skill than traditionally used parameters of tracking error stabilization and minimization of emotional-autonomic shifts. Computation of the ratio of grip strength to tracking error makes it possible to estimate the "physiological cost" and, thus, reliability of operator performance. The device for registering grip strength is incorporated into the control system and may be used in systems providing continuous diagnostic information without interfering with operator performance.

Aerospace Medicine↗
PubMed1987

Slow oscillations of psychophysiological parameters in human operators during monotony.

Objective estimation of the human operator's functional state is an urgent problem in applied psychophysiology. It helps to forecast the reliability and efficiency of the operator's activity. Slow (minute) changes in the functional state of 22 subjects were recorded and analysed in experiments simulating the long-term operator's activity. Spatial synchronization of the electroencephalogram (EEG) and the heart-rate (HR) served as parameters. It was shown that the time of detection and identification of visual signals (geometrical figures) amid visual "noise" in a long-term observation naturally depends on the changes in a subject's state. These changes were estimated by slow (2-3 min) components of the changes in spatial synchronization of EEG and HR throughout 3 h of the experiment. These objective parameters of the human operator's state may be used to predict efficiency. The connection between minute oscillations of electrophysiological parameters and time of reaction is absent during the first 30 min of the experiment, then appears and increases throughout further stages, becoming clearly marked in its second half.

Boredom↗
PubMed1985

Blink reflex as a parameter of human operator's functional state.

Eyelid movements (EM)--blinking frequency and duration of closed eyes--may serve as a parameter of fatigue in humans performing as operators. Twenty subjects were told to locate and follow visual signals appearing on a screen at the frequency of 4-5 X h-1 and moving in a background of bright noises. EM was recorded in infra-red rays with tiny sensors attached to glasses' rim. EEG and ECG were recorded simultaneously. It was found that a change in EM is a sensitive parameter of fatigue and better corresponds to decreased quality of performance (time of locating signal and error in following), than changes in R-R interval. In the second experimental series, symptoms of fatigue discovered by EM were accompanied by sound signals, which improved operator's performance by 15-20%. Recording of EM may be used to monitor operator's state in humans and to forecast reliability of performance.

Achievement↗
PubMed1980

Psychophysiological monitoring of operator's emotional stress in aviation and astronautics.

The level of emotional stress depending on the power of motivation and the estimation by the subject of the probability (possibility) of goal achievement, largely influences the operator's skill performance (that of a pilot, controller, astronaut). A decrease in the emotional tonus leads to drowsiness, lack of vigilance, missing of significant signals, and to slower reactions. The extremely high stress level disorganizes the activity, complicates it with a trend toward untimely acts and reactions to the insignificant signals (false alarms). The best methods to monitor the degree of the operator's emotional state during his skill performance are the integral estimation of the changes in heart-rate and T-peak amplitude, as well as the analysis of spectral and intonational characteristics of the human voice during radio conversation. These methods were tested on paratroopers, pilots in civil aviation, and airport controllers.

Aerospace Medicine↗
PubMed1978

Psychophysiological forecasting of efficiency.

The method of mathematical forecasting of the changes in efficiency throughout an increase in emotional stress is suggested on the basis of experimental data from experiments in which paratroopers discerned visual patterns. The comparison of human errors with the experimental results obtained in animals permitted formulation of several suppositions on the role of different cerebral structures in the genesis of emotional stress and the mechanisms of its effect on perceptive activity.

Aviation↗
PubMed1977

Analysis of the human voice as a method of controlling emotional state: achievements and goals.

Background factors and those of formant structure, spectral and spectro-temporal characteristics of rapid and slow speech components, temporal peculiarities, and intensity of speech turned out to be informative indices of the human emotional state. Application of mathematical methods, in particular methods of recognition theory, to these factors helped to assess the degree and the psychological sign of emotion, to diagnose the status of attention and fatigue, and to differentiate emotional and physical stress. The paper outlines the results obtained in model experiments on cosmonaut A. Leonov at different flight stages, including EVA, on Voskhod-2.

Emotions↗
PubMed1977

Effect of emotional stress on recognition of visual patterns.

The object of the study was to observe the changes in efficiency of perceptive activity of man (recognition of visual patterns against a background of noises) throughout an increase in emotional stress caused by a forthcoming parachuete jump. A moderate degree of emotional stress can improve performance efficiency and decrease the number of the subject's errors. Later an impairment of differentation of similar signals was seen and an increase in the number of "false alarm" errors along with a decrease in the number of omissions to reactions signals. The neurophysiological basis of such changes in perceptive activity consists in a transition from conditional behaviour to reaction through mechanisms of Ukhtomsky's dominant focus.

Aerospace Medicine↗
PubMed1975

Characteristics of the electrocardio-gram under physical and emotional stress in man.

The changes in the length of interval R-R and in heart rate are widely used for estimation of man's physical state. How-ever, this ECG index has several drawbacks including a relatively low sensitivity and non-specificity, unindirection of changes under different states: attention and fatigue, physical and emotional stress, etc. Moreover, one and the same factor, e.g. emotional stress, can lead both to a decrease and an increase in the heart rate. Hence, it is necessary to find other more adquate ECG parameters, which would enhance the reliability and accuracy of assessment of man's state. The analysis of data found in literature and the results of our preliminary experiments have shown that the amplitude of the t-peak and duration of the R-T interval of ECG can be used as such parameters.

Adaptation, Physiological↗
PubMed1975

Use of the invariant method of speech analysis to discern the emotional state of announcers.

An improved method of discerning emotional colouring of speech on the frequency of main tone and average number of intersections at zero level within the range of first formant frequencies is described. Vowels from words pronounced by announcers in different emotional states served as material for experiments. The method elaborated in the experiments with actors and drama school undergraduates was then tested in natural conditions on amateur parachute jumpers.

Emotions↗
PubMedDate not supplied

Problems of the analysis of altered states of consciousness.

It is assumed on the basis of data that have been obtained that altered states of consciousness (ASC) arise during the performance of operator activity under conditions of monotony, when modulating influences in the minute range of fluctuations are experienced in the process. This modulation promotes the attenuation or intensification of the degree of ASC; this is reflected in corresponding shifts in attention and in the quality of operator actions relating to recognition of visual images. These results point to the important role of the modulating system of the brain, and of its infraslow wave manifestations in the activity of consciousness whose content is determined by informational processes.

Adult↗
PubMedDate not supplied

Recognition of visual images in a rich sensory environment: musical accompaniment.

Human recognition of visual images in the form of Arabic numerals affected by "noise" showed a reduction in the time needed for recognition and an increase in the probability of making a correct identification in a rich sensory environment (use of classical or rock music). There was no direct relationship between the volume of the music and its positive effect on the recognition of visual images. The greatest changes in the recognition time and quality of correct recognition occurred at specific volume levels for both classical and rock music, and there were individual differences. The efficiency of image recognition decreased when the same musical fragments were used again with the same volume. The data are interpreted as a manifestation of the dominant.

Cognition↗
PubMedDate not supplied

Informational need of emotional stress.

According to the informational theory of emotions, emotions in humans depend on the power of some need (motivation) and the estimation by the subject of the probability (possibility) of the need satisfaction (the goal achievement). Low probability of need satisfaction leads to negative emotions, actively minimized by the subject. Increased probability of satisfaction, as compared to earlier forecast, generates positive emotions, which the subject tries to maximize, i.e. to enhance, to prolong, to repeat. The informational theory of emotions encompasses their reflective function, the laws of their appearance, the regulatory significance of emotions, and their role in organization of behavior. The level of emotional stress influences the operator's performance. A decrease in the emotional tonus leads to drowsiness, lack of vigilance, missing of significant signals and to slower reactions. An extremely high stress level disorganizes the activity, complicates it with a trend toward incorrect actions and reactions to insignificant signals (false alarms). The neurophysiological mechanisms of the influence of emotions on perceptual activity and operator performance as well as the significance of individuality are discussed.

Aerospace Medicine↗