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91.
We applied the scaffold-free culture method to chondrocytes and attempted to reconstitute articular cartilage grafts. Primary rat costal chondrocytes were immobilized into hollow fibers by centrifugation at a density of 3 x 10(8) cells/cm(3) to induce the formation of cylindrical-shaped multicellular aggregates (organoids) and cultured for one month. The organoids were evaluated by histological and gene expression analyses. Chondrocytes formed cylindrical organoids in hollow fibers (HFs). Histochemical analysis revealed the accumulation of a cartilage extracellular matrix (collagen and proteoglycan) around cells in the lumen of HFs with culture time, forming a low-cellular-density tissue similar to native cartilage by day 28. Furthermore, in contrast to that in traditional monolayer culture, the organoid maintained the gene expression of the cartilage extracellular matrix (type II collagen, aggrecan) for one month of culture. In conclusion, our organoid formation method was effective in producing a cartilage-like tissue. This result suggests that the technique may be applicable to the development of an articular cartilage graft. 相似文献
92.
Yoshihisa Kosugi Masato Goto Zhenhong Tan Asaya Fujita Takashi Saito Takashi Kamiyama Wei-Tin Chen Yu-Chun Chuang Hwo-Shuenn Sheu Daisuke Kan Yuichi Shimakawa 《Advanced functional materials》2021,31(25):2009476
Materials which show novel thermal properties can be used to make highly efficient and environmentally friendly energy systems for thermal energy storage and refrigeration through caloric effects. An A-site-ordered quadruple perovskite-structure oxide, NdCu3Fe4O12, is found to release significant latent heat, 25.5 kJ kg−1 (157 J cc−1), at the intersite-charge-transfer transition temperature near room temperature. The transition is first-order and accompanied by an unusual magnetic ordering and a large negative-thermal-expansion-like volume change, and thus, it causes a large entropy change (84.2 J K−1 kg−1). The observed entropy change is comparable to the largest changes reported in inorganic solid materials, and more importantly, it is utilized through a colossal barocaloric effect. The adiabatic temperature change by applying 5.1 kbar pressure is estimated to reach 13.7 K, which means efficient refrigeration can be realized through this effect. 相似文献
93.
Hiroki Tanji Ryo Tanaka Takahiro Murakami Yoshihisa Ishida 《Signal, Image and Video Processing》2016,10(6):1105-1112
In this paper, we propose a nonparametric Bayesian model combined with the Indian buffet process (IBP) for a finite impulse response (FIR) system. We develop an FIR system identification method that can simultaneously estimate the number of FIR taps and coefficients. In the proposed model, each FIR tap consists of a coefficient and a gain, and the gain is a binary value. An infinite-dimensional binary vector is composed of binary values, and we assume that this binary vector is generated by the IBP. To identify the FIR system, we specify the likelihood function and prior distributions of the parameters and derive their posterior distributions. We can simultaneously estimate the number of FIR taps and coefficients by sampling from posterior distributions using the Gibbs sampler. Our simulations demonstrate that although the number of FIR taps is unknown, the identification performance of the proposed method in a high signal-to-noise ratio environment is similar to or better than that of the conventional least square solution. 相似文献
94.
Fujisaki S Fujisaki Y Ishiwara H 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(12):2592-2594
Characteristics of metal-ferroelectrics-metal (MFM) capacitors and meta -ferroelectrics-insulator-semiconductor (MFIS) diodes with poly(vinylidene fluoridetrifluoroethylene) [P(VDF-TrFE)] copolymer films thinner than 100 nm were investigated. The films were prepared by spin cast process and were annealed at 140 degrees C in air for crystallization. The ferroelectric properties are equivalent to those of oxide ferroelectrics, even under low voltage or high frequency operation. 相似文献
95.
Sugihara T Tsuji Y Sakai K 《Journal of the Optical Society of America. A, Optics, image science, and vision》2007,24(1):18-24
A recent physiological finding of neural coding for border ownership (BO) that defines the direction of a figure with respect to the border has provided a possible basis for figure-ground segregation. To explore the underlying neural mechanisms of BO, we investigated stimulus configurations that activate BO circuitry through psychophysical investigation of the BO-dependent tilt aftereffect (BO-TAE). Specifically, we examined robustness of the border ownership signal by determining whether the BO-TAE is observed when gestalt factors are broken. The results showed significant BO-TAEs even when a global shape was not explicitly given due to the ambiguity of the contour, suggesting a contour-independent mechanism for BO coding. 相似文献
96.
By using the characteristics of a hydrogen-absorbing alloy, the hydrogen produced by catalytic dehydrogenation of saturated
compounds can be absorbed to form metal hydrides, and, vice versa, the resulting metal hydrides are able to hydrogenate efficiently
unsaturated compounds upon dehydriding. Gas-phase reactions between 2-butene and 2-propanol on a hydrogen-absorbing alloy
CaNi5 have been studied in the temperature range of 393–473 K. CaNi5 showed interesting characteristics as an active catalyst for the catalytic transfer hydrogenation of butene from propanol
as a hydrogen donor. 2-propanol was effectively dehydrogenated at 423 K to yield acetone in which the dissociated hydrogen
was completely absorbed by CaNi5 to form the metal hydride. When the alloy was hydrided to some extent, butene was hydrogenated by the absorbed hydrogen in
the metal hydride to produce butane. The overall reaction on CaNi5 was expressed as catalytic transfer hydrogenation of 2-butene from 2-propanol through intermediate formation of metal hydrides,
rather than the direct reaction between butene and propanol on the alloy. Thus, CaNi5 effectively repeated hydriding–dehydriding cycles: hydriding of CaNi5 by 2-propanol dehydrogenation with subsequent dehydriding for the hydrogenation of 2-butene. The use of hydrogen-absorbing
CaNi5 provides a novel reaction system for the catalytic transfer hydrogenation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
97.
Fujino E Fujino T Karita S Kimura T Sakka K Ohmiya K 《Journal of Bioscience and Bioengineering》1999,87(4):535-537
The porphobilinogen deaminase encoded by the Clostridium josui hemC gene was purified from a recombinant Escherichia coli strain and its properties were characterized. The optimal temperature and pH of the purified enzyme were 65 degrees C and 7.0, respectively. This enzyme was quite thermostable: it retained 86% of the original activity after incubation at 70 degrees C for 1 h. The Km and Vmax values of the enzyme were 65 microM and 3.3 micromol/h/mg for porphobilinogen, respectively. 相似文献
98.
Yoshihisa Maeyama Kazunori Kadota Akira Kitayama Yuichi Tozuka Mikio Yoshida Atsuko Shimosaka Yoshiyuki Shirakawa 《International Journal of Hydrogen Energy》2017,42(16):11501-11509
A hybrid simulation was carried out using discrete variational (DV) Xα molecular orbital and molecular dynamics methods to examine the storage of hydrogen in metal nanoparticles. The calculation load was light and therefore could be performed quickly on a generic personal computer. The simulation investigates the electronic states of hydrogen on Pd and Ti nanoparticles. The hydrogen dissociation behavior on the metal surface was reproduced, and the calculated bonding orbitals of Pd and hydrogen are consistent with other reports. The diffusion coefficient of hydrogen inside the metal displays the same temperature dependence as the theoretical results. This simplified calculation, which produces results in agreement with experimental/theoretical values, could lead to improved simulation methods for hydrogen storage materials. 相似文献
99.
Kazuyoshi Torii Kenichi Shoji Hiroshi Kawakami Takao Kumihashi Toshihiko Itoga Natsuki Yokoyama Masahiro Moniwa Tooru Kaga Yoshihisa Fujisaki 《Electrical Engineering in Japan》1997,121(1):43-50
A one-mask-patterned ferroelectric capacitor test structure designed with a 0.5-μm feature size was fabricated. Oxygen plasma treatment after dry etching decreased the leakage current to as low as that of as-deposited film. These one-mask-patterned ferroelectric capacitors, with switching charge almost equal to as-deposited film, were successfully fabricated. Ferroelectric memories as dense as dynamic random access memories will become possible with this technology. However, the leakage current density for micron-sized capacitors is 2 to 10 times that of large capacitors. The leakage current in small capacitors is increased due to perimeter leakage that runs through the damaged region on the capacitor sidewall. © Scripta Technica, Inc. Electr Eng Jpn, 121(1): 43–50, 1997 相似文献
100.
Shigeyuki Nakamura Yoshihisa Mori Ken’ichi Takarabe 《Journal of Electronic Materials》2014,43(6):2174-2178
High-performance Mg2Si thermoelectric devices have been obtained by spark plasma sintering of high-purity, pre-synthesized, all-molten Mg2Si powder. We studied the effects of source powder particle size on thermoelectric performance. To improve the performance, further investigation of the microstructure of the devices is needed. In this work we studied the microstructure of grain boundaries and interfaces between electrodes and Mg2Si sintered bodies to increase understanding of Mg2Si thermoelectric devices. 相似文献