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排序方式: 共有548条查询结果,搜索用时 31 毫秒
121.
K Sawada K Koizumi T Tarumi H Takano M Ieko M Nishio Y Fukada T Yasukouchi M Yamaguchi T Koike 《Canadian Metallurgical Quarterly》1999,23(1):1-11
Extrapolation of animal data to assess pharmacokinetic parameters in humans is an important tool in drug development. Allometric scaling has many proponents, and many different approaches and techniques have been proposed to optimise the prediction of pharmacokinetic parameters from animals to humans. The allometric approach is based on the power function Y = aWb, where the bodyweight of the species is plotted against the pharmacokinetic parameter of interest on a log-log scale. Clearance, volume of distribution and elimination half-life are the 3 most frequently extrapolated pharmacokinetic parameters. Clearance is not predicted very well (error between predicted and observed clearance > 30%) using the basic allometric equation in most cases. Thus, several other approaches have been proposed. An early approach was the concept of neoteny, where the clearance is predicted on the basis of species bodyweight and maximum life-span potential. A second approach uses a 2-term power equation based on brain and body weight to predict the intrinsic clearance of drugs that are primarily eliminated by phase I oxidative metabolism. Most recently, the use of the product of brain weight and clearance has been proposed. A literature review reveals different degrees of success of improved prediction with the different methods for various drugs. In a comparative study, the determining factor in selecting a method for prediction of clearance was found to be the value of the exponent. Integration of in vitro data into in vivo clearance to improve the predictive performance of clearance has also been suggested. Although there are proponents of using body surface area instead of bodyweight, no advantage has been noted in this approach. It has also been noted that the unbound clearance of a drug cannot be predicted any better than the total body clearance (CL). In general, there is a good correlation between bodyweight and volume of the central compartment (Vc); hence, Vc does not face the same complications as CL. The relationship between elimination half-life (t 1/2 beta) and bodyweight across species results in poor correlation, most probably because of the hybrid nature of this parameter. When a reasonable prediction of CL and Vc is made, t 1/2 beta may be predicted from the equation t 1/2 beta = 0.693 Vc/CL. 相似文献
122.
Yu Mitsui Shoko Seto Mari Nishio Kazuya Minato Kimiharu Ishizawa Shigeru Satoh 《Biomass & bioenergy》2010,34(4):467-473
The present study was conducted to select willow (Salix spp.) clones with a high potential for use as biomass energy crops in the southern region of Tohoku district in Japan. Cuttings of 8 willow clones were planted on an abandoned farmland near Sendai (av. annual temp., 10.9 °C) in March 2006, grown throughout the year and cut back in late December 2006 to resprout from the remaining stools in March 2007. The biomass yield in December 2007, after the first growing season, was highest in Salix pet-susu clone KKD, followed by Salix pseudolinearis clone FXM and Salix sachalinensis clone SEN. The biomass yield on December 2008, after the second growing season, was again highest in clone KKD followed by clone FXM, S. pet-susu clone HB471 and S. sachalinensis clone SEN; the average annual yield of dry mass after the second growing season being 3.09, 2.58, 2.17 and 1.85 kgDM plant?1 for the clones in this order. Plant growth form differed among the clones. Clones FXM and SEN had several shoots of almost uniform base diameter, whereas clones KKD and HB471 showed plagiotropic growth with one thick and several thin shoots. The calorific values of dried stem segments were similar among clones, ranging from 18.7 to 19.1 kJ g?1. The dried stem segments contained 78.9–81.2 wt.% hollocellulose, 27.2–32.3 wt.% lignin and 2.1–4.0 wt.% extractives with ethanol-benzene, depending on clones. Based on these results, we could select four clones (KKD, FXM, HB471 and SEN) suitable for biomass production by SRWC in this area. 相似文献
123.
Abstract Wood flour (WF) was converted not only to thermoplastic material but also to carrier matrix for in-situ synthesis of iron oxide nano-particles by a set of etherification; namely, considerable hydroxypropylation and modest carboxymethylation. A sequence of procedure for the in-situ synthesis of iron oxides includes ferrous ion-absorption of the etherified WF, precipitation of ferrous hydroxide by an alkaline treatment, and oxidation of the ferrous hydroxide. Magnetometry measurements revealed that the magnetic woody composite showed superparamagnetism (SPM) at room temperature. The observation of SPM may be of significance in the perceptibility to an external magnetic stimulus only on demand and without energy loss. 相似文献
124.
Nguyen Thu Ha Keisuke Kaneda Yoshitaka Naitoh Lina Fukuhara Kenichiro Kosugi Seiichi Kawahara 《应用聚合物科学杂志》2015,132(34)
Preparation and graft‐copolymerization of hydrogenated natural rubber are performed in latex stage after removal of proteins from the rubber with urea and surfactant. Hydrogenation of deproteinized natural rubber (DPNR) latex is carried out with palladium catalyst under hydrogen atmosphere. The hydrogenated DPNR (HDPNR) is crosslinked with a peroxide followed by graft‐copolymerization of styrene (Sty) and acrylonitrile (AN) in latex stage in order to prepare a graft‐copolymer of crosslinked HDPNR with poly(Sty‐co‐AN) (HDPNR‐graft‐PSAN). Characterization of the products is performed by nuclear magnetic resonance spectroscopy. The conversion of hydrogenation is investigated with respect to the catalyst feed, acidity (pH), and dry rubber content. In the resulting HDPNR‐graft‐PSAN, mole fraction of AN and Sty is 1.4 and 5.8 mol %, respectively. The graft‐copolymer is used to improve properties of PSAN as an impact modifier. The Charpy impact strength of crosslinked HDPNR‐graft‐PSAN/PSAN is about eight times as high as that of PSAN. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42435. 相似文献
125.
Yoichi Ishiwata Eiko Takahashi Kenta Akashi Masaki Imamura Junpei Azuma Kazutoshi Takahashi Masao Kamada Hirofumi Ishii Yen‐Fa Liao Yasuhisa Tezuka Yuji Inagaki Tatsuya Kawae Daisuke Nishio‐Hamane Masashi Nantoh Koji Ishibashi Tetsuya Kida 《Advanced Materials Interfaces》2015,2(12)
A first‐order phase transition in a bulk material is generally considered to arise at extended defects such as grain boundaries or dislocations, where the energetic barrier between the two phases is reduced. Downsizing a crystal to the nanoscale can exclude the number of defects, leading to enhanced kinetic stabilization of the metastable phase. Here, the disappearance of the first‐order metal–insulator transition in defect‐free V2O3 nanocrystals and the revival of the transition by introducing a certain Cr or Ti impurity content are investigated. The hysteresis width of the transition corresponding to the barrier height decreases with the impurity content. It is proposed that homogeneous impurity doping is a universal method that can control the occurrence of a first‐order phase transition in nanoscale materials. 相似文献
126.
Integration of free-space-wave add-drop multiplexers that consist of focusing grating couplers (FGCs) and distributed Bragg reflectors (DBRs) in thin-film waveguides have been investigated for construction of an intraboard wavelength-division-multiplexing optical interconnection. Compact optics of a Lloyd mirror configuration and a contact-type mask aligner were combined as an interference exposure system for fabrication of DBRs of 300 microm coupling length. DBRs were integrated with FGCs on a thin-film waveguide on a glass substrate for two-channel wavelength-drop demultiplexing from guided waves to free-space waves. Measured outcoupled wavelengths of two free-space waves from two pairs of a FGC and a DBR agreed with the design values of 845 and 849 nm. 相似文献
127.
Observation of sea-ice thickness in the sea of Okhotsk by using dual-frequency and fully polarimetric airborne SAR (pi-SAR) data 总被引:1,自引:0,他引:1
Nakamura K. Wakabayashi H. Naoki K. Nishio F. Moriyama T. Uratsuka S. 《Geoscience and Remote Sensing, IEEE Transactions on》2005,43(11):2460-2469
To investigate the possibilities of using dual-frequency, multipolarization synthetic aperture radar (SAR) data to monitor sea ice, we derived the relationship between various polarization characteristics and the physical parameters of sea ice. We discuss the frequency and polarization characteristics of the backscattering coefficients of sea ice and then characterize its thickness by comparing the corresponding backscattering coefficient for each polarization with the physical parameters of the ice. We first propose a methodology for classifying sea-ice types by using a polarimetric decomposition technique, before comparing an estimation of the sea-ice thickness with the corresponding dual-frequency, multipolarization SAR data. We utilized the backscattering ratio to estimate the thickness of the sea ice. This ratio canceled the effect of roughness on the backscattering. The method was validated using Pi-SAR (polarimetric and interferometric airborne SAR) observation data obtained at ground-truth sites. 相似文献
128.
Tatsuo Nishizawa Kenji Himeno Kenichiro Nomura Kitaro Uchida 《Canadian Metallurgical Quarterly》2001,1(3):351-369
A new structural model for pavements on steel bridge decks (SLPE) is developed. In this model, a prism element and a strip element represent the pavement and steel bridge deck, respectively. A newly developed link element models the insulation layer that bonds the pavement to the steel deck plate. The SLPE model is verified by calculations that simulate a simply supported square plate and an actual pavement on a bridge deck. Furthermore, the model is expanded to deal with dynamic problems that consider the viscosity of asphalt materials. 相似文献
129.
H. Hayashida F. Ishibashi H. Takahata T. Nishio Y. Gotoh Y. Sato 《Polymer Engineering and Science》1998,38(10):1633-1639
A new process, the Non Anchor Coating Extrusion Laminating Process for producing an extrusion laminated film without any chemical primer, was investigated. Good adhesive properties were obtained by combining an ozone treatment of a molten polyethylene (LDPE) web and an activation treatment of the polyamide (ONy) substrate film. The adhesion mechanism induced by the new process was studied by FT-IR, ESCA and extraction of unreacted polyamide from the laminated samples. The peel strength between the ONy and LDPE laminated films produced with this process was greater than that for laminated film made with a conventional lamination process using anchor coating agents. A model of the adhesive mechanism is proposed. Hydrogen and covalent bonds through oxygenated functional groups are responsible for the enhanced adhesion. 相似文献
130.