No change in the optical density at 260 mpi was observed when solutions of calf thymus DNA (pH 4.8—9.9) containing 1 % formaldehyde, were exposed to up to 9,000 atm for 60 min at 30°C. This shows that DNA is quite stable at high pressure. Heat denaturation of DNA (71.5-77.5°C) is retarded by compression. This retarda-tion increases with pressures of up to 4,000 atm and then levels off. From kinetic results on heat denaturation, the values of 4S * are 33 to 39 e.u. and those of AV* are 11 to 14 ml/mole. These results are compared with those for proteins, reported in the previous publications, and the differences between them are discussed. Denaturation of proteins at high pressure has been investigated (1,2). Most proteins are denatured in the region of 3,000 to 10,000 atm. Lower pressures (up to 3,000 atm) do not cause denaturation but retard heat denatura-tion of the proteins. Studies on the pressure sensitivity on DNA have been reported recently by Heden and co-workers (3), and Weida and Gill (4). The former found from measurement of transformation after releasing the pressure, that exposure of DNA from B. subtilis to a pressure of 10,000 atm did not cause denatura-tion and that a pressure of 2,700 atm retarded heat denaturation. Weida and Gill also found that pressure retarded heat denaturation of calf thymus DNA from direct measurement of optical rotation under pressures of up to about 1,400 atm. In the study of Heden and co-workers, however, it was impossible to check whether DNA was denatured by pres-sure if the denaturation was reversed com-pletely on releasing the pressure. In the present report, formaldehyde was added to aqueous solutions of calf thymus DNA to prevent the reformation of hydrogen bonds between bases after releasing the pres-sure (5). Moreover, the effect of pressure in retarding heat denaturation was studied kinetically to acquire further information on the mechanism of this reaction. EXPERIMENTAL Materials-Ca\i thymus DNA (Lot 15 B-1790) was obtained from Sigma Chemical Co. Ltd. Its £(p) at 260m ^ was 8,560 at pH 7.8 (0.015 M sodium citrate and 0. 15 M NaCl) and

Copyright © 2014 Yoshiaki Taniguchi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We propose a method for tracking multiple

Pedestrian counting with grid-based binary sensors based on Monte Carlo method Shuto Fujii1*, Yoshiaki Taniguchi2, Go Hasegawa3 and Morito Matsuoka3 In this paper, we propose a method for estimating the number of pedestrians walking in opposite directions, as in cases of a shopping street or a

is possible (Taniguchi et al., 2005). However, this invasive procedure can only be performed under general anesthe-sia. Therefore, the development of a noninvasive method is desirable. There are reports evaluating action potentials of the cauda equ-ina and spinal cord from outside of the body (Cracco, 1973

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A traveling wave-based self-organizing communication mechanism for WSNs

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We have proposed a self-organizing communication mechanism for wireless sensor networks where a large number of sensor nodes are deployed. In this paper, we briefly introduce and overview our communication mechanism. In our mechanism, to accomplish application-oriented periodic communication without any centralized controls, we adopt traveling wave phenomena of a pulse-coupled oscillator model by regarding sensor nodes as oscillators and emission of radio signals as firing. Simulation results show that our mechanism delivers sensor information to a designated node in a more energy-efficient manner than other method, although it takes time to generate a traveling wave. In addition, we show implementation of our mechanism using MOTE MICAz and its practicality. 1