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Many lives and facilities were lost by fire. Especially, there are many damages to elderly, toddlers and babies. In Japan, number of deaths over 65 years old reached to 53% in 2004. Number of over 81 years olds went to 20%. It takes for the elderly person more time to sense fire and also to evacuate to safe places. Although it is important to prevent the fire, it also needs to inform the fire breaking as early as possible. Human sense decreases with age and it is difficult to perceive the fire at an early stage. It is desired to develop a higher sensitive element for fire and its system which can detect fire at an early stage. In this experiment, tin oxide gas sensors were adopted to detect a smoldering fire at the early stage. Most common case of fire is the smoldering fire. The reliability of the sensor is higher and it is adopted in a gas alarm detector. The sensor can also detect slight amount of odor molecule. In our previous experiment, it became obvious that it was better to install the sensor to the ceiling to detect odor components generating from smoldering fire. Therefore, five sensors were installed in the ceiling away from each other and the method to detect the fire was examined. As a result, a characteristic was newly derived by adding the sensor outputs for one minute. The sensor output was input every 0.1s. The characteristic is called as the integrated characteristic. After that, the differential characteristic was derived using the integrated characteristic. The fire was determined using the differential characteristics. The materials causing a smoldering fire were woodchip, wallpaper and carpet as subjects. The system could detect the fire in several minutes for whole materials. The sensor is effective to detect the smoldering fire at an early stage. It is necessary to detect a cigarette smoke to distinguish as non fire. In this study, the discrimination was also examined using a quadratic function (ax2+b). The coefficients a and b were effective to identify smoldering fire and cigarette smoke. Principal component analysis for the arrival speed S which meant a kind of odor-speed was also useful to distinguish fire from non fire.

A taste sensor is composed of several kinds of lipid/polymer membranes as transducers which convert taste information to electric signal. Thus, the role of membranes is very important to detect various taste components. In this paper, we developed novel membranes which specifically respond to quinine that is typical bitter substances. These membranes were composed of hydrophobic ionic liquid such as N, N, N-trimethyl-N-propylammonium bis(trifluoromethansulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butylpyridinium hexafluorophosphate, a plasticizer, 2-nitrophenyl octyl ether and a polymer, polyvinyl chloride. In addition to quinine, they also showed response to both several kinds of alkaloids such as caffeine and strychnine, and non-alkaloid such as phenylthiocarbamide. The order of these responses was equal to that of the tongue glossopharyngeal nerve of flog. Furthermore, there were the other alkaloids which response to these membranes. Especially in these alkaloids, they showed high response to denatonium benzoate and berberin chloride which have a strong bitter taste.

In this study, we report the sensitive detection of aromatic nitro compounds using a surface plasmon resonance (SPR) immunosensor based on the indirect competitive method. The vapors from the substances were sampled with a preconcentrator developed here. The solutions of the sampled vapors were measured using SPR immunosensor. Three kinds of explosives such as 2,4-dinitrobenzene, 2,4-dinitrotoluene, and 2,4,6-trinitrotoluene were detected at 1 ppb. Sampling time at 1 l/min was 3 min. Total detection time was brought down to 5 min, which is relatively short for second scanning in landmine detection. Efforts are being made to integrate the SPR immunosensor and preconcentrator for rapid sensitive detection of nitro aromatic compounds under simulated field conditions.

A taste sensor with global selectivity is composed of several kinds of lipid/polymer membranes for transforming information of taste substances into electric signal. The sensor output shows different patterns for chemical substances which have different taste qualities such as saltiness and sourness. Taste interactions such as suppression effect, which occurs between bitterness and sweetness, can be detected and quantified using the taste sensor. The taste and also smell of foodstuffs such as beer, coffee, mineral water, soup and milk can be discussed quantitatively. The taste sensor provides the objective scale for the human sensory expression. Multi-modal communication becomes possible using a taste/smell recognition microchip, which produces virtual taste. We are now standing at the beginning of a new age of communication using digitized taste.

A multichannel taste sensor using lipid/polymer membranes has higher sensitivities to electrolytes such as sour and salty substances than nonelectrolytes such as sweet substances. The purpose of this study is to improve sensitivity to sweet taste substances. The response to sweetness is assumed to have a mechanism different from electrolytic taste substances due to its nonelectrolyte. We could make large improvement of the response to sweetness by mixing positively and negatively charged lipid/polymer membranes and utilizing their hydrophobic property.

This paper describes an application of taste sensor for detection of a trace amount of organic substances. This sensor consists of multichannel sensors with lipid membranes which are modeled on living organisms. One of characteristics of this sensor is a global selectivity. We discovered that organic substances have large influences on the adsorption of a plus charged lipid (additive in a solution) to a lipid membrane made by minus charged lipid. Using this method, some of organic substances, such as oil, Trichioroethylene and Di-2-ethylhexylphthalate, could be detected about 100ppb within five minutes. In conclusion, the taste sensor has a possibility for real-time monitoring of water quality using this new methods.

It has been noticed recently that there is a possibility of elution of chemical substances from packages of foods. The chemicals act as harmful substances such as environmental hormones for biological bodies at very low concentration. It is therefore necessary to develop a sensing device, which can detect such substances easily and quickly. The purpose of the present study is high sensitive measurement of environmental hormones using electrode polarity controlling method. The responding ability of the polarity-controlled sensor covers various chemicals from electrolytes to nonelectrolytes and from hydrophilic to hydrophobic substances. As a result, we could sensitively detect bisphenol-A at about 50ppb and dibutyl phthalate at about 3ppb, and the sensor could distinguish such chemicals from ordinary taste substances.

Taste can be measured using a taste sensor, which shows different electrical potential patterns for each food. The sensor has eight kinds of lipid membranes. The present study is concerned with the long-term measurements of milk and sensory analysis of milk. Each membrane was preserved in standard milk, and the tastes of five kinds of commercial milk were measured using the sensor preserved for a period of one month to six months in the same manner. It was found that calibrated data was comparable with data obtained other days, and that the membranes were used reliably fbr six months. On the other hand, richness of sensory test showed a high correlation with the ratio of milk fat using chemical analysis, as seen from the correlation coefficient 0.829. It was also found that there is significant difference among the four samples by performing a Kramer test (α

Amino acids with different functional group show different taste such as bitterness, sweetness and umami. Some of them elicit complicated mixed taste; e. g., L-methionine tastes bitter and sweet simultaneously. A multichannel taste sensor using lipid membranes was applied to amino acids. It was shown that bitter amino acids such as L-tryptophan have response electric patterns similar to a typical bitter substance, quinine, that belongs to alkaloids. The response pattern for L-methionine was found to be similar to that for a mixed solution composed of a sweet amino acid (L-alanine) and bitter amino acid (L-tryptophan). These results agreed quantitatively with human sensory evaluations.

The present study investigates adsorption of taste substances to lipid membranes for the multichannel taste sensor. To clarify the mechanism of adsorption of taste substances to a lipid membrane, we measured adsorption quantities of taste substances, such as amino acids and quinine-HCl, with fluorometry, and the surface of the lipid membrane was analyzed with ESCA (Electron spectroscopy for chemical analysis). Furthermore, we measured potential responses of a lipid membrane and pH of monosodium glutamate and lipid solutions. The results showed that amino acids adsorb to the lipid membrane, but no specific adsorption site exists on the membrane. The adsorption occurred by weak interaction between a phosphoric acid group of lipid molecules and an amino group of amino acids. Quinine-HCl adsorbed to membrane with strong electrostatic coupling and weak hydrophobic effects to lipid molecules in the membrane.

This paper describes an application of taste sensor for detection of cyanide. The taste sensor consists of multichannel sensors with lipid membranes which are modeled on living organisms. One of characteristics of this sensor is a global selectivity. In this study, we have developed a new effective method which is able to control the charge of membranes for high sensitivity and selectivity of lipid membrane sensors. Using this method, sensors for free cyanide and complex cyanide were developed. We could detect total cyanide under the guideline limit. It was possible to detect free cyanide below the concentration 0.5ppm in river water. Measurement time is within five minutes. In conclusion, the taste sensor has a very powerful performance and advantage for real time monitoring of water quality.

A multichannel taste sensor can respond to many kinds of chemical substances simultaneously with high sensitivity. It has a possibility to measure various substances that remain in used food packages. The purpose of the present research is to detect chemical substances which were dissolved to aqueous solution from three materials such as raw materials of PET bottles (poly (ethyleneterephthalate)), used PET bottles and recycled egg packages. We found that there is no metalic ions in these samples and hydrophobic substances were dissolved from used PET bottles and recycled egg packages. Additionally, we used near-infrared spectroscopy to analyze the substances; however, no significant spectrum was not found. This result implies that the multichannel taste sensor can be used to evaluate the quality of recycled food packages.

We have developed a multichannel taste sensor with lipid membranes which can detect and quantify the basic taste substances in aqueous solution. The aim of the present study is to increase selectivity to adsorptive taste substances (bitter, umami and astringent taste substances) for quantification of taste by improving measuring methods. High selectivity to adsorptive taste substances is obtained by CPA measurement algorithm (CPA: Change of membrane Potential caused by Adsorption). High repeatability is also obtained by developing a cleaning technique of taste sensor.

Response mechanism of a membrane made of trioctylmethylammonium chloride (TOMA) to ethanol was studied. The response of the TOMA membrane to ethanol increased linearly with increasing ethanol concentration (0-20%) at constant KCl concentration. The slope of response to ethanol was-1.73 (mV/ethanol%) using the multiple regression analysis (0-20% ethanol, 1-100 mMKCI). The value of this slope calculated using the transfer activity coefficient of chloride ion from water to ethanol showed a good agreement with the experimental value. On the other hand, the results obtained in AgCl and anion exchange membrane disagreed with the theoretical values.

Impedance changes in phospholipid LB (Langmuir-Blodgett) and protein-mixed phospholipid LB films by several taste substances were measured. The resistance of the phospholipid LB film increased by bitter and sweet substances, whereas the resistance decreased for salty, sour and umami substances. For sweetness the larger change was observed in the protein-mixed phospholipid LB film, and hence discrimination between sweetness and bitterness was possible.

Detection of some toxic substances in water is a time consuming process because large number of substances need to be analyzed. When some toxic substances in the drains flow into the river, they cause environmental destruction. Accurate detection of substances which have serious effects on living organism is required as well as short measurement time. Although a sensing system employing living fish is devised, there are some problems in reliability, maintenance and evaluation because they are living thing. It is possible to measure the influence of pollutant for living organism directly by a sensor which is similar to biological systems. So we investigate a method of detection of toxic substances by multichannel lipid membrane sensors which are modeled on living organism.SA401 has multichannel sensor with lipid membranes which are modeled on living organism. It is able to detect some toxic substances in the water. For the reason, this system has been applied to measure water quality, such as, mineral water, tap water, contaminated river water and factory drains. We have found this method is effective and many pollutants (e. g. CN-, Fe3+, Cu2+, etc.), in factory drains, have been measured in a few minutes, the detection limits are lower than regulations of drain. It is possible to detect cyanide of factory drains selectively in short time by applying lipid membrane sensor. In conclusion, it is an effective mean to use multichannel lipid membrane sensors for observation of water quality especially for factory drains.

Interactions between a lipid-protein membrane and taste substances were investigated using SPR (surface plasmon resonance). The used membrane was the LB (Langmuir-Blodgett) multi-layered film composed of DHP (dihexadecyl phosphate) and the sugar-binding protein ConA. The LB membrane including ConA showed larger responses to almost all the taste substances, such as quinine, caffeine, sucrose and NaCl than the LB membrane without ConA. Suggestion was also made on the interactions of astringent and pungent substances with the charged lipid LB membrane.

Taste can be quantified using a multichannel taste sensor with lipid/polymer membranes. Its sensitivity and stability are superior to those of humans. A present study is concerned with the first step of miniaturization and integration of the taste sensor with lipid/polymer membranes using FET. As a result, it was found that gate-source voltage of the taste sensing FET showed the same behaviours as the conventional taste sensor utilizing the membrane-potential change due to five kinds of taste substances. Discrimination of foodstuffs was very easy. A thin lipid membrane formed using LB technique was also tried. These results will open doors to fabrication of a miniaturized, integrated taste sensing system.

The taste of beer was measured using a taste sensing system with eight kinds of lipid membrane. The output from the sensor has high discriminating power and high correlation with taste substances in beer and sensory test by human. The estimation of the concentration of taste substances by multiple regression analysis was fairly well. The taste sensor also well estimated the result of sensory test of many keywords concerning beer taste.

We have developed a multichannel taste sensor with artifical lipid membranes and have applied it to quantification of taste of green tea. We used multiple regression analysis and found high correlations of outputs of the taste sensor with the results of sensory test (taste, flavor and color) and chemical analyses (amino acids and tannin that are main taste substances in green tea). It is concluded that the taste sensor has a potential for quantification of taste of green tea. The taste sensor responds not only to amino acids and tannin, but also to many other taste substances, and hence it contains much more taste information than conventional chemical analyses.