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991.
Takahiro Harada Akihiro Isomura Kenichi Yoshikawa 《Physica D: Nonlinear Phenomena》2008,237(21):2787-2796
The evolution of the spatial arrangement of cells in a primary culture of cardiac tissue derived from newborn rats was studied experimentally over an extended period. It was found that cells attract each other spontaneously to form a clustered structure over the timescale of several days. These clusters exhibit spontaneous rhythmic contraction and have been confirmed to consist of cardiac muscle cells. The addition of a contraction inhibitor (2,3-butanedione-2-monoxime) to the culture medium resulted in the inhibition of both the spontaneous contractions exhibited by the cells as well as the formation of clusters. Furthermore, the formation of clusters is suppressed when high concentrations of collagen are used for coating the substratum to which the cells adhere. From these experimental observations, it was deduced that the cells are mechanically stressed by the tension associated with repeated contractions and that this results in the cells becoming compact and attracting each other, finally resulting in the formation of clusters. This process can be interpreted as modulation of a cellular network by the activity associated with contraction, which could be employed to control cellular networks by modifying the dynamics associated with the contractions in cardiac tissue culture. 相似文献
992.
Jan Burke Kenichi Hibino Ryohei Hanayama Bozenko F. Oreb 《Optics and Lasers in Engineering》2007,45(2):326
Wavelength-shifting interferometry can distinguish in frequency space interference signals from different surfaces, and therefore allows the measurement of optical thickness variation between several quasi-parallel surfaces of a composite transparent object. Frequency analysis of the signal spectrum with a tunable phase-shifting formula can then detect the phase of the individual signals. We have devised a tunable phase-shifting method which uses a freely adjustable number of intensity samples and can be adapted to any frequency spectrum. To extract the signal reliably, two properties of the phase-shifting method are particularly important: it should suppress cross-talk from unwanted frequencies, and it should allow for some variation in the signal frequency. We show that a carefully designed sampling function envelope will combine these benefits, and demonstrate the technique in measurements of three different composite objects each consisting of three reflecting surfaces. The importance of phase-shift linearisation is discussed, and methods for selecting optimal set-up parameters are given. 相似文献
993.
Kenichi Takita Hideaki Nakane Goro Masuya 《Proceedings of the Combustion Institute》2007,31(2):2513-2520
Ignition tests by double plasma jet (PJ) torches in a supersonic flow were conducted. Two PJ torches with different feedstocks were arranged in a straight line in the direction of flow. The Mach number of the airflow was 2.3, and the total temperature and total pressure of the main flow were those of room conditions. A C2H4 fuel perpendicularly injected with its sonic speed into the main flow was tested. A combination of O2–O2 feedstocks for the two torches was more effective than other combinations such as H2/N2–O2. Moreover, the effectiveness of the double PJs was found to be almost the same as that of a single PJ. These results indicate that combustion reactions of the main fuel injected upstream of the PJ were mostly completed in the vicinity of the upstream PJ. The upstream PJ was considered to be dominant for ignition and the combustion process, indicating that the influence of the downstream PJ was small. On the other hand, the advantage of the double PJs over the single PJ in reducing damage to the torch nozzle was confirmed. 相似文献
994.
Ogata A. Yamanouchi K. Mizuno K. Kushiyama S. Yamamoto T. 《Plasma Chemistry and Plasma Processing》1999,19(3):383-394
The combination of plasma discharge and adsorption was examined for oxidation of dilute benzene in air in a plasma reactor packed with a mixture of BaTiO
3
pellets and porous Al
2
O
3
pellets (i.e., an alumina hybrid reactor). The oxidative decomposition of benzene was enhanced by the benzene concentrating on the Al
2
O
3
pellets. Furthermore, there was a higher selectivity to CO
2
in the products from the hybrid than from a plasma reactor packed with BaTiO
3
pellets alone. The presence of the Al
2
O
3
pellets suppressed the formation of N
2
O. 相似文献
995.
996.
Crystal structures of solid solutions of BiMn1−xScxO3 with x=0.05, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.7 were studied with synchrotron X-ray powder diffraction. The strong Jahn-Teller distortion, observed in BiMnO3 at 300 K and associated with orbital order, disappeared already in BiMn0.95Sc0.05O3. The orbital-ordered phase did not appear in BiMn0.95Sc0.05O3 down to 90 K. Almost the same octahedral distortions were observed in BiMn1−xScxO3 with 0.05?x?0.7 at room temperature and in BiMnO3 at 550 K above the orbital ordering temperature TOO=473 K. These results allowed us to conclude that the remaining octahedral distortions observed in BiMnO3 above TOO are the structural feature originated from the highly distorted monoclinic structure. 相似文献
997.
Yasushi Morihara Shin‐Ichi Ogata Masanobu Kamitakahara Chikara Ohtsuki Masao Tanihara 《Journal of polymer science. Part A, Polymer chemistry》2005,43(23):6048-6056
A triple‐helix‐forming collagen model peptide, (prolyl‐trans‐4‐hydroxyprolyl‐glycyl)10 [(Pro‐Hyp‐Gly)10], and a thermosensitive elastin‐derived pentapeptide, valyl‐prolyl‐glycyl‐valyl‐glycyl (Val‐Pro‐Gly‐Val‐Gly), were copolymerized in various mole ratios using 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide hydrochloride and 1‐hydroxybenzotriazole in dimethyl sulfoxide at 20 °C. All of the obtained polypeptides have molecular weight higher than 103 and contain a triple‐helical structure, and showed an inverse phase transition from transparent solution to turbid suspension in response to a rise in temperature. The lower critical solution temperature of the polypeptide solution decreased upon increasing the content of Val‐Pro‐Gly‐Val‐Gly. Furthermore, polypeptides containing 82–86 mol % of Val‐Pro‐Gly‐Val‐Gly in composition showed reversible gel formation, suggesting that (Pro‐Hyp‐Gly)10 acts as a hydrated unit and Val‐Pro‐Gly‐Val‐Gly acts as a thermosensitive crosslinking point. These biodegradable thermosensitive polypeptides may be useful for biomedical applications, including, as a scaffold for tissue regeneration. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6048–6056, 2005 相似文献
998.
T. Nakamura Atsushi Ogata Takahiro Hoshi Retsu Oiwa 《Fresenius' Journal of Analytical Chemistry》1998,362(3):254-257
In quantitative XPS, the preparation of reference samples is difficult or impossible, and the correction factor method has
been employed. Therefore, a convenient and practical procedure to get correction factors to estimate atomic ratios is proposed,
in which it is assumed that the XPS intensity distribution corresponds to the distribution of the photoionization cross section.
This procedure can be applied to some instruments and various samples without the previous collection, preparation of reference
sample groups, and determination of sensitivity factors for each element.
Received: 8 October 1997 / Revised: 23 February 1998 / Accepted: 28 February 1998 相似文献
999.
Junya Takahashi Osamu Fujita Kenichi Ito 《Proceedings of the Combustion Institute》2005,30(2):2311-2317
The objective of this work was to investigate the effect of external radiation angle on radiative ignition of solid materials. A laser ignition experiment was performed in microgravity to investigate events occurring in the ignition process in a quiescent atmosphere. Filter paper was used as the test material, and it was heated by infrared radiation (CO2 laser 10.6 μm) or near-infrared radiation (diode laser, 800.1 nm). The ignition time was determined for various irradiation angles, and the gas phase density change before ignition was observed by a Mach–Zehnder interferometer for each test condition. The results showed that the ignition by CO2 laser occurred on the laser beam line depending on the irradiation angle, while diode laser caused a similar ignition position independent of the irradiation angle. The period from gasification to ignition with CO2 laser was almost the same for different irradiation angles, while it varied with the irradiation angle for diode laser, and the ignition time was much shorter than that with diode laser. According to these results, it is considered that solid ignition with inclined external radiation is characterized based on (1) solid surface heating and (2) gas phase heating, and the second factor, gas phase heating, causes the different dependence of solid ignition on irradiation angle with different radiation wavelengths. 相似文献
1000.
Kohei Sanui Naoya Ogata Kazuyuki Kamitani Masayoshi Watanabe 《Journal of polymer science. Part A, Polymer chemistry》1993,31(3):597-602
Direct polycondensation of 3-substituted-4-hydroxybenzoic acid was carried out in solutions of styrene-butadiene block copolymers (SBS) at room temperature in the presence of triphenylphosphine and hexachloroethane as an initiator for the direct polycondensation of these monomers. Solution casting after the direct polycondensation provided opaque films in which the aromatic polyester was finely dispersed within the matrix of SBS. Mechanical properties of these films were examined by tensile tests. A great improvement of tensile strength was achieved by the incorporation of phenyl substituent in the resulting polyester. In-situ direct polycondensation leads to the formation of new composites of rigid polymers and flexible polymers. © 1993 John Wiley & Sons, Inc. 相似文献