Based on set theory, a phylogenic tree of materials is obtained by arranging physical attributes of present organisms, such as 'homeostatic', in the order of the evolution that preceded life. The tree indicates that thirty attributes should have been acquired by a material system in advance to 'physical border' representing a cell membrane, and also that two different series of attributes, which start at 'homeostatic' and 'singular distribution, ' merge at 'physical border.' These results suggest that cell membrane had been generated by highly complex mechanisms consisting of, at least, the stabilization in a set of molecules and the repulsion between the sets. The tree also suggests the candidates of reactions for the creation of 'physical border.' Computer simulation shows that physical borders are created in the candidate system. This method is applicable to the origins of other important attributes of life.

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A multichannel taste sensor is composed of several kinds of lipid/polymer membranes for transforming information of substances producing taste into electric signals, which are input to a computer. The sensor output shows different patterns for chemical substances which have different taste qualities such as saltiness, sourness and bitterness, while it shows similar patterns for chemical substances with similar tastes. The sensor responds to the taste itself, as can be understood from the fact that taste interactions such as the suppression effect, which appears between sweet and bitter substances, can be reproduced well. The suppression of the bitterness of quinine and a drug substance by sucrose can be quantified. Amino acids can be classified into several groups according to their own tastes based on sensor outputs. The taste of foodstuffs such as beer and mineral water can be discussed quantitatively using the taste sensor, which provides the objective scale for the human sensory expression. The taste sensor will open doors to a new era of membrane, food and environmental sciences.

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Cultured neural network is a useful tool for the understanding of fundamental functions and structure of nervous system. In this biological neural network, nerve cells mutually communicate by electrical or chemical interactions, and exhibit collective dynamics of activities such as synchronous bursting or calcium wave propagation. Photostimulation by using caged-glutamate were performed to elucidate the mechanism of Ca wave propagations through the measurement of the speed of Ca wave, rising time of Ca increase, and range of propagation, etc. To analyze the activity and dynamical connectivity of the cultured network, we quantified spontaneous collective dynamics of the network by lowering magnesium concentration in extracellular solution. From the visualization of network structure, cell type discrimination by MAP2 monochronal antibody, and measurement of dynamical activity by [Ca²⁺] sensitive dye, we quantitatively elucidated that collectivity of the network activities were increased due to the development of long-range interaction between neurons.

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In the present study, pervaporation of MeOH/MTBE was studied by using blended membranes from agarose and various hydrophilic polymers. Polyoxyethylene/agarose blended membranes selectively transported MeOH from MeOH/MTBE mixtures. Permselectivity toward MeOH reached 9×10⁵. The addition of polyoxyethylene to agarose membrane led to the increase in flux compared with agarose membrane. The blended membranes from polyoxyethylene and agarose can be used as one of promising membranes for the separation of MeOH from MTBE production.

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