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81.
Mizuno K Somiya H Kubo T Matsukawa M Otani T Tsujimoto T 《The Journal of the Acoustical Society of America》2010,128(5):3181-3189
The influence of cancellous bone microstructure on the ultrasonic wave propagation of fast and slow waves was experimentally investigated. Four spherical cancellous bone specimens extracted from two bovine femora were prepared for the estimation of acoustical and structural anisotropies of cancellous bone. In vitro measurements were performed using a PVDF transducer (excited by a single sinusoidal wave at 1 MHz) by rotating the spherical specimens. In addition, the mean intercept length (MIL) and bone volume fraction (BV/TV) were estimated by X-ray micro-computed tomography. Separation of the fast and slow waves was clearly observed in two specimens. The fast wave speed was strongly dependent on the wave propagation direction, with the maximum speed along the main trabecular direction. The fast wave speed increased with the MIL. The slow wave speed, however, was almost constant. The fast wave speeds were statistically higher, and their amplitudes were statistically lower in the case of wave separation than in that of wave overlap. 相似文献
82.
Takatoki Yamamoto Mami Hino Rei Kakuhata Takahiko Nojima Yasuo Shinohara Yoshinobu Baba Teruo Fujii 《Analytical sciences》2008,24(2):243-246
A living cell has numerous proteins, only a few thousand of which have been identified to date. Cell-free protein synthesis is a useful and promising technique to discover and produce various proteins that might be beneficial for biotechnological, pharmaceutical, and medical applications. For this study, we evaluated the performance and the general applicability of our previously developed microreactor array chip to cell-free protein synthesis by comparisons with a commercially available system. The microreactor array chip comprises a temperature control chip made of glass and a disposable reaction chamber chip made of polydimethylsiloxane (PDMS). For evaluation of the microreactor array chip, rat adipose-type fatty acid binding protein, glyceraldehyde-3-phosphate dehydrogenase, cyclophilin, and firefly luciferase were synthesized from their respective DNA templates using a cell-free extract prepared from Escherichia coli. All these proteins were synthesized in the microreactor array chip, and their respective amounts and yields were investigated quantitatively. 相似文献
83.
The chemotypes found in various plant species are the good subjects for the studies to understand the regulatory mechanism in secondary metabolism. The biochemistry and molecular biology of flavonoid biosynthesis was studied using chemotypes of Perilla frutescens var. crispa differing anthocyanin accumulation. The expression of the most of structural genes for anthocyanin biosynthesis was coordinately regulated in chemotype-specific manner and by light. However, the genes for shared enzymes between anthocyanin and flavone pathway were expressed both chemotypes. Biochemical characteristics of enzymes involved in anthocyanin biosynthesis were investigated in this plant. Furthermore, the candidates of regulatory factors, members of MYB-bHLH-WD complex, of anthocyanin production were characterized in this plant. 相似文献
84.
Sato T Hoshino H Yoshida S Nakajima M Hoshino T 《Journal of the American Chemical Society》2011,133(44):17540-17543
This study demonstrates that a tetraprenyl-β-curcumene cyclase, which was originally identified as a sesquarterpene cyclase that converts a head-to-tail type of monocycle to a pentacycle, also cyclizes a tail-to-tail type of linear squalene into a bicyclic triterpenol, 8α-hydroxypolypoda-13,17,21-triene. The 8α-hydroxypolypoda-13,17,21-triene was found to be a natural triterpene from B. megaterium. It was also demonstrated that cyclizations of both tetraprenyl-β-curcumene and squalene occurred with a purified B. megaterium TC homologue in the same reaction mixture. These results suggest that the tetraprenyl-β-curcumene cyclase is bifunctional, cyclizing both tetraprenyl-β-curcumene and squalene in vivo. This is the first report describing a bifunctional terpene cyclase, which biosynthesizes two classes of cyclic terpenes with different numbers of carbons as natural products in the organism. 相似文献
85.
Hatem Oueslati Salah Ben Mabrouk Abdelkader Mami 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(2):130-145
The work presented in this article focuses on the analysis and modelling of heat and mass transfers in the tunnel dryer during the drying of agricultural products. The main objective of this work is to establish a global modelling of the studied system based on the bond graph methodology. The pseudo-bond graph methodology was used in modelling the system. Such methodology was very suitable for this thermal process since it allows good management of the nonlinearity present in the system.The thermal performance of the proposed dryer is analysed by solving the various energy balance equations. An application of drying tomatoes was achieved and a fair agreement was observed between predicted and experimental results. 相似文献
86.
Six novel neomacrophorin and four novel premacrophorin congeners were isolated from the fungus Trichoderma sp. 1212-03. Their planar structures and relative configurations were determined by conventional NMR and mass spectrometry techniques. The electronic circular dichroism (ECD) spectral comparisons with known neomacrophorins were effective for elucidating the structures of congeners carrying 2,3-epoxybenzoquinone (1, 2) and 2,3-epoxybenzosemiquinol substructures (3, 4, 5, 7, 8, and 9). The configuration of the 6-hydroxy-2-cyclohexene-1,4-dione moiety in 5′-deoxyneomacrophorin IV (6) was elucidated by NMR spectral comparison with those of known purpurogemutantidin (16) and mancrophorin F (17). This also resulted in the configurational revision of 16. The relative configuration of the 5,6-epoxy-2-cyclohexen-1,4-diol in premacrophorintriol-II (10) was determined by 13C chemical shift analysis using density functional theory calculations at the ωB97X-D/6-31G* level of theory. Compounds 1 and 6 exhibited potent cytotoxicity against human Caucasian colon adenocarcinoma cell line COLO 201. 相似文献
87.
M. Abbes A. Farhat A. Mami 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2019,25(1):90-114
This research work is focused on the construction of an accurate longwave/shortwave radiation model on a tunnel greenhouse pseudo-bond graph model, widely used in Tunisia. This model includes sun position, useful incoming solar radiation model, sky longwave radiation model, inside longwave and shortwave radiation model. The key idea is to use bond graphs allowing a lumped modelling approach which is suitable for control applications. Furthermore, an evaluation of some longwave radiative model components was made, noting that these components are particularly sensitive regarding to the thermal behaviour of the model.
Experimental tunnel greenhouse data are used as validation elements for the present model with globally good results. A comparative study was also performed between the present model and a previous bond graph model containing a simplistic radiative model. Practical simulation results show a clear improvement compared with the previous model. 相似文献
88.
89.
One-pot reaction of [CpCo(CO)2], elemental sulfur with some heterocycle-substituted alkynes (R-CC-HET) produced [CpCo(dithiolene)] complexes with 2PyOBn (2), with both 2PyOBn and 2-hydroxy-2-propyl groups (C(OH)Me2) (5), both 2Py and C(OH)Me2 (8), both 4Py and C(OH)Me2 (11), and with 4Py substituent (13). A deprotection of benzyl group (Bn) from 2 with trimethylsilyl iodide formed [CpCo(dithiolene)] with 2-pyridonyl substituent (3). Heating reaction of 8 without any base resulted in the C(OH)Me2 group elimination to form the 2-pyridylethylenedithiolate complex (9), but 11 underwent only dehydration at the C(OH)Me2 under heating. While the preparation of 5, the benzyl free complex (6) was obtained as a main product. 6 has a dithiolene-fused tricyclic pyridone skeleton. The structures of 3, 5, 6, 8, and 11 were determined by X-ray diffraction studies. Intramolecular OH?N(2Py) hydrogen bondings are found in 5 and 8, and an intermolecular OH?N(4Py) one is found in 11 at solid state. In the 2-pyridonyl complex 3, intermolecular NH?O and CH(dithiolene)?O hydrogen bondings are observed. 8 showed an intermolecular Cp?Cp face-to-face interaction. The tricyclic complex 6 exhibited lower energy electronic absorption (λmax = 668 nm) compared with the others (λmax = 562-614 nm), due to an extended π-conjugation of aromatic cobaltadithiolene ring. 相似文献
90.
The detailed spatial distributions of longitudinal ultrasonic velocity in cortical bone specimens obtained from three bovine femoral diaphysis were experimentally investigated using a pulse-echo system. The relationship between velocity, density, bone mineral density (BMD) and microstructure was investigated. Velocity was found to vary as a function of the direction of propagation and the location of the measured specimens in the bone diaphysis. A significant correlation was found between density and velocity, and between density and BMD. In some parts with plexiform structure, clear variations in velocity anisotropy were found despite no significant difference in density, BMD and microstructure. 相似文献