A new technique for amplification of photothermal beam deflection angle was developed. This technique, based on a very simple operation principle, uses a cylindrical reflection mirror for a new deflection amplifier. This paper presents experimental data and the results of theoretical analysis. Mirage signal amplification of more than 35 times was achieved. Additionally, mirage signals obtained with this new deflection-angle amplifier did not significantly decrease even in the high modulation frequency range.

Abstract:A new technique has been developed for amplification of the photothermal beam deflection angle for mirage detection. This technique, based on a very simple operating principle, uses a cylindrical reflection mirror. The use of a new amplifier provided a signal-to-noise ratio approximately 10 times that obtained without the amplifier for equipment of the same size. By using the new amplifier, a mirage signal was obtained when a transistor array processed on a silicon wafer was measured.

We earlier showed that intestinal STC-1 cells can respond to five basic taste stimuli. Here, we investigated which receptors or channels are involved in the sensing of umami in STC-1 cells. T1R family and metabotropic glutamate receptors were not involved. In contrast, we found that N-Methyl-D-aspartate (NMDA) receptors are expressed in STC-1 cells by RT-PCR analysis. Using a calcium-imaging technique, we also observed that a specific agonist NMDA induces the increase in the intracellular Ca concentration in STC-1 cells. We also found that pretreatment with NMDA enhances sweet-induced response in STC-1 cells, suggesting important roles of L-Glu-signaling in the chemosensory system of the gastrointestinal tracts.