The idea of molecular automaton is generalized to the eukaryote cells and the model of the digital genetic system is hybridized with that of the biochemical continuous system. The continuous system under the control of the automaton may correspond to the kinematic machine of von Neumann's theory. This idea is applied to the kinetics of the regulatory metabolites during the cell cycle, G₁, S, G₂ and M, and the automaton model having various time delays, instead of the hybridized continuous system, is considered. The mechanism of mitosis, for example, may be due to such a kinematic machine. Such a model may be useful in considering the mechanism of cancerization, anti-body formation and so on.
In this review physical interpretation of the genetic information is given, which should be related with the entropy of activation of the rate process of mRNA formation or of protein synthesis. There is a large bottleneck corresponding to the small probability of the arrangement of monomers of a given base sequence and the bottleneck is enlarged by the base interaction. This idea is confirmed by the statistical thermodynamical theory of rate processes. Any physical or chemical action affecting the bottleneck may be called “information” and the flux of the rate process, the corresponding “response”.

View full abstract

In general, feature extraction in the image processing requires formidable computations. A feature extraction method which incorporates local data operation and relatively simple algorithm has been developed. This method, named Geometric Factor Method, utilizes the geometry computation theory in Perceptrons. The images in the mesh space are analyzed and feature values in them are extracted according to patterns of squares, that is, the geometric factors as defined here. Feature values of randomly generated circles, triangles and rectangles are extracted and evaluated in a simulation based on the method. Also, the method is tested on classification of human white cells for medical image processing application.

View full abstract

A mathematical model of cones, horizontal cells, and bipolar cells on light and dark adaptation was proposed. From this model, both transient and steady state responses of these cells to prolonged illumination could be obtained. In the case of bipolar cells, spatial responses to a spot or a ring could be obtained. Simulated results coincided with recent physiological studies in that the dynamic ranges in the responses of these cells could be shifted to higher intensities by increasing background illumination and that bipolar and horizontal cells responded over narrower ranges of intensities than cones. Weber's law held for cells of this model when the intensity of background illumination was strong enough. At the low level of background illumination the model of bipolar cell lost the surround input of its receptive field and at high level it became center-surround type. The physiological meanings of the assumptions proposed in this model are discussed.

View full abstract

The importance of parallel pathways of the systemic circulation in the control of overall cardiovascular system was studied with an analytical model based on our recent experimental studies of isolated perfused organs.
The major units considered are : large arteries, large veins, and the peripheral circulation. The last is subdivided into three parallel functional units : 1) nutritional bed, 2) shunt pathway and 3) storage area. By addition of simplified linear descriptions for the heart and the pulmonary circulation, an algebraic equation relating cardiac output to systemic circulatory parameters was derived. which provided a convenient means of studying effects of parameter changes.
This equation made it clear that the cardiac output is mainly limited by the systemic circulatory parameters at normal conditions. It also predicted that constriction of arterioles of a peripheral vascular unit would either enhance or diminish the cardiac output depending on the relationship of resistances and compliances of the parallel pathways. The characteristics of the parallel pathways were also noted in the simulated transient response of the systemic blood volume to the step change of venous pressure at right heart bypass experiment.
It was concluded that systemic mechanics appeared to influence cardiac output by redistribution of blood volume rather than redistribution of blood flow.

View full abstract

It has been known that muscular activity is associated with a tremor in the 8-12 Hz band. In the previous paper the author proposed the lumped parameter model of the stretch reflex arc. In consequence of the good agreement of the simulation results with the experimental results, the hypothesis that this tremor is largely due to the oscillation in the stretch reflex arc was proposed. Recent study by S. Mori with respect to the discharge patterns of soleus motor units and associated changes in force exerted by foot has demonstrated the following facts. In the initial stage with sporadic presence of the oscillations of force, motor units exhibited stationary and asynchronous discharges. With the continuous presence of the oscillations, the discharges of motor units became synchronized with the firing rate of about 10 spikes/sec. And in the transitional stage, spike dropouts from an otherwise regular spike train were observed. In this paper the model of the stretch reflex arc consisting of many NMUs is proposed. One NMU consists of an α motoneuron, a motor unit and a muscle spindle. These NMUs interact each other through GIa afferent signals. Ac.cording to the simulation results, when interaction of the NMUs caused by afferent signals is small, motor units exhibited stationary and asynchronous discharges. As the interaction becomes larger, the discharges of motor units are synchronized. In accordance with the experimental results, the spike dropouts are observed in the transitional stage.

View full abstract