Seiichi Suzuki

This article has no abstract.

In this study, a high separation ratio micro-fluidic cell sorting by dielectrophoretic (DEP) force is presented. Resent development of iPS cell technology has promoted the possibility of regenerative therapy. In technologies of genetic cell processing requires purification of specific target cells by cell sorter. Most prevailing system for cell separation is the flow cytometry (FCM), which has been developed for research purpose. In spite of the high performance in separation ratio, it takes rather high cost in one operation. For clinical use, a device contacting biological specimen must be disposable to prevent cross infection. A low cost micro-fluidic cell sorter, using DEP force, can be fabricated by photolithography technique. However, sorting rate of existing DEP cell sorter is far lower than that of FCM because of the limitation of applicable voltage in aqueous fluid. To circumvent the problem and raise the DEP force, implementation of field gradient dependence was investigated. The design of flow channel was deiced to make high gradient at the separation point, and enhance the DEP force. Distribution of the electric field was proved to have a peak intensity at the entrance of separation channel by numerical calculated of Finite Element Method. DEP separation of 2μm diameter latex beads at the rate of 3.0mm/sec, 6 times large than that of our previous system, was demonstrated. © 2012 The Institute of Electrical Engineers of Japan.

We've developed a system for presenting 3D information by stereo-sounds synthesized from stereo CCD image. The synthesized sound must be compatible with the sound from real environment to avoid confusion. However it's difficult to synthesize sounds carrying really recognizable 3D information for headphone, because the acoustic impedance of the head and head motion must be considered. In this work, real time sound synthesis system was developed to investigate the effects of real time tracking of the head motion. The results showed that the head motion tracking largely improves the directional localization resolution.

We developed, tested and evaluated a new device for skin thermal resistance measurement (TR), employing zero heat flow technique. This device enables almost non-invasive measurement and acquisition of intact skin TR. The relationship between human arousal level and skin TR was examined by simultaneous measurement of EEG and TR. The correlation coefficient of human arousal level and skin TR transition measured 0.6-0.7. The response time for TR measurement is as slow as few minutes but fast enough for detection of the arousal level change. This device is expected as a method for long term monitoring of human physiological state.

A novel method of immnobilization of antibody molecule on porous structure, for the development of fluorescence anistropy immunosensor, was proposed. In this study composition of silica hydrogel-forming mixture was investigated , in concern with the porosity and diffusion of large biological molecule. Gel forming condition was optimized and gel sheet 0.3mm in thickness was defined on quartz substrate by microfabication technique. Fab' of IgG was covalently immobilized on the gel sheet to acquire larger fluorescence signal. The antibody fragment maintained it' s intact binding activity and showed higher anisotropy change on binding of specific antigen

Immunoassay is a useful method for the detection of biological material and is expected for the application on proteome screening. Inspite of their exelent characteristics, small sample amount, high speed and integration of multiple sensing points, some kinds of immunosensor are not free from nonspecific adsorption of contamination. On the contrary, Fluorescence anisotorpy measurement of fluorescent labeled antibody enables immunoassay free from nonspecific background eventhough smaller S/N ratio is attained compared with vulk measurement. In this study, we examined evanescent light exitation to attain higher S/N ratio.

Auditory stimulus is an important source of information about surrounding objects. The Sonic-glass is one of the most excellent device that enhances the sound localization ability. However, such a passive methods inevitably provide limited sort of information, and some kind of information, velocity of the objects or concave for instance, are difficult to recognize with sound. Addition of visual information on the natural sound, by the computer synthesized sound, will overcome his difficulty. In this method, however, the compatibility of the synthesized sound with the natural stimulus is critical for inconsistent artificial stimulus may be annoying and, in worst case, even disturb the ordinary localization. In this context, localizable sound was synthesized on a PC and it's compatibility with natural sound was examined.

Auditory stimulus is an important source of information about surrounding objects. The Sonic-glass is one of the most excellent device that enhances the sound localization ability. However, such a passive methods inevitably provide limited sort of information, and some kind of information, velocity of the objects or concave for instance, are difficult to recognize with sound. Addition of visual information on the natural sound, by the computer synthesized sound, will overcome his difficulty. In this method, however, the compatibility of the synthesized sound with the natural stimulus is critical for inconsistent artificial stimulus may be annoying and, in worst case, even disturb the ordinary localization. In this context, localizable sound was synthesized on a PC and it's compatibility with natural sound was examined.