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81.
Jan Andres Tom Fürst Karel Pastor 《Journal of Mathematical Analysis and Applications》2008,340(2):1132-1144
A full analogy of the celebrated Sharkovsky cycle coexistence theorem is established for lower semicontinuous (multivalued) maps on metrizable linear continua. This result is further extended to triangular maps. 相似文献
82.
Karel indel JiÍ Holubek Emil Svtek Olue Matouov Jiina Metyov Miroslav Protiva 《Journal of heterocyclic chemistry》1989,26(5):1325-1330
Reactions of dibenzo[b,e]thiepin-11(6H)-one (4) with 2-, 3- and 4-(dimethylaminomethyl)phenylmagnesium bromide afforded the tertiary alcohols 5a,b,c. The aldehydes 7 and 8 gave similarly the secondary alcohols 9a,b,c and 10c . Numerous attempts to prepare the corresponding ketones, especially by oxidation of 9a,b,c and 10c were unsuccessful. Only the oxidation of 9c with tetrabutylammonium chromate in chloroform afforded the desired ketone 16 . Its formation was accompanied by an important side reaction consisting in a cleavage of the “retro-ene-reaction” type leading to compound 11 and the aldehyde 13c which reacted with the chloroform present to give the alcohol 17 . Compounds 5a,b,c, 9a,b,c and 16 were tested as potential antidepressants but with the exception of some effects in the test of potentiation of yohimbine toxicity in mice, they proved inactive in this line. 相似文献
83.
A hyperbolic problem with volume constraint is investigated by means of a minimizing method called the discrete Morse flow. A weak solution is introduced in a constructive way and results of numerical computations are shown. 相似文献
84.
Emiliano Fernández Daniel López Carmen Mijangos Miroslava Duskova‐Smrckova Michal Ilavsky Karel Dusek 《Journal of Polymer Science.Polymer Physics》2008,46(3):322-328
In this article, we report on the rheological properties of agarose aqueous solutions and gels. Viscosity curves were determined for homogeneous agarose aqueous solutions at different temperatures (from 68 to 38 °C) to study the viscosity behavior as the systems undergo gelation. The gelation phenomenon of agarose solutions was also investigated by shear oscillation experiments and differential scanning calorimetry. The gelation and melting temperature as a function of agarose concentration were determined together with the gelation and melting enthalpies. The results obtained were interpreted using the two‐step model describing the gelation of agarose in water. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 322–328, 2008 相似文献
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-5-Aryl-1-[2-(phosphonomethoxy)ethyl]uracils were prepared via Pd-catalyzed Suzuki-Miyaura coupling reaction of the appropriate 5-bromouracil derivative with a series of arylboronic acids followed by deprotection. These compounds were designed as potential multisubstrate inhibitors of thymidine phosphorylase based on an assumption that the potential hydrophobic effect of the aryl groups might modify the inhibitory effect towards this enzyme and they may also demonstrate cytostatic activity. 相似文献
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