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111.
Tautness and Lie sphere geometry 总被引:1,自引:0,他引:1
112.
Mana-Hox, an analog of beta-carbolines with anticancer activity, induces aberrant mitosis and delays mitotic exit. However, the cellular target is not known. In this study, we visualized the intracellular localization of Mana-Hox. Mana-Hox rapidly penetrated into cells (within 1 min) and concentrated on disorganized metaphase chromosomes after 13 hr of exposure. We demonstrated that Mana-Hox is a noncovalent DNA binder that can interact with DNA through intercalation and/or through minor groove binding. Furthermore, Mana-Hox also inhibits topoisomerase II relaxation activity in vitro, suggesting that Mana-Hox could perturb mitotic chromosome decatenation. Overall, Mana-Hox binding to DNA plays a critical role in the induction of aberrant mitosis and contributes to its anticancer activity. 相似文献
113.
A reaction of 2-aminobenzenesulfonamide ( 1 ) with 2-chloroethyl or 3-chloropropyl isothiocyanate in isopropanol afforded 2-(2′-chloroethylthioureido)- and 2-(3′-chloropropylthioureido)benzenesulfonamides ( 2a,b ) in 67% and 55% yield respectively. Treatment of 2a,b with triethylamine in methanol at room temperature furnished 3-(2′-aminoethylthio)- and 3-(3′-aminopropylthio)-2H-1,2,4-benzothiadiazine 1,1-dioxides ( 9a,b ) in quantitative yield. Heating 2b to reflux in methanol under neutral conditions gave 9b but in the form of the hydrochloride 8b which could be converted into the free base 9b by treating with ammonia water. When compounds 2a,b were treated with triethylamine in methanol at elevated temperature, 3-(2′-mercaptoethylamino)- and 3-(3′-mercaptopropylamino)-2H-1,2,4-benzothiadiazine 1,1-dioxides ( 10a,b ) were obtained in good yield. Alternatively, 10a,b could also be prepared from 9a,b in 95% and 77% yield respectively. 相似文献
114.
The diffusion constant determining the rate of the variation in the stoichiometric composition of CdTe for a change in cadmium pressure is measured for indium doped crystals. The results for doped as well as undoped crystals are expressed in terms of previously determined equiconcentration tracer diffusion constants using a detailed point defect model. Factors responsible for asymmetrical behavior are discussed. 相似文献
115.
Maw-Cherng Suen Shih-Fu Chiang Jhy-Der Chen Shuenn-Shing Chern Chwan-Deng Hsiao 《中国化学会会志》1998,45(2):263-268
The quadruply bonded complexes containing bridging acetate and polydentate phosphine ligands of the type Mo2(O2CCR3)XJ(η3-etp) (R = H, X = Br, 1; R = F, X = CI, 2; R = F, X = Br, 3; etp = Ph2PCH2CH2P(Ph)CH2CH2PPh2) were prepared by reactions of Mo2(O2CCR3)X2(PPh3)2 with etp in CH2X2. Their UV-vis and 31P{1H}-NMR spectra have been recorded, and the structure of 1 has been determined by X-ray crystallography. Crystal data for 1·2CH2Br2: space group P21/c, a = 13.924(7) Å, b = 21.157(4) Å, c = 14.427(5) Å, β = 101.82(3)°, V = 4159(2) Å3, Z = 4, with final residuals R = 0.0797 and Rw = 0.0793. The absorption wavelengths of the δ → δ* transitions and the chemical shifts and the coupling constants of the 31P{1H}-NMR spectra of these complexes are dependent on the natures of the halogen atoms and the acetate ligands. 相似文献
116.
Chorng‐Shyan Chern Cheng Lee 《Journal of polymer science. Part A, Polymer chemistry》2002,40(10):1608-1624
Amphiphilic graft copolymers consisting of monomeric units of poly(ethylene glycol) monomethyl ether acrylate, lauryl or stearyl methacrylate, and 2‐hydroxyethyl methacrylate were synthesized and characterized. The effectiveness of these poly(ethylene glycol)‐containing graft copolymers in stabilizing styrene emulsion polymerization was evaluated. The polymerization rate (Rp) increases with increasing graft copolymer concentration, initiator concentration, or temperature. At a constant graft copolymer concentration, Rp increases, and the amount of coagulum decreases with the increasing hydrophilicity of graft copolymers. The polymerization system does not follow Smith–Ewart case II kinetics. The desorption of free radicals out of latex particles plays an important role in the polymerization kinetics. The overall activation energy and the activation energy for the radical desorption process are 85.4 and 34.3 kJ/mol, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1608–1624, 2002 相似文献
117.
Isoguanosine ( 3 ) underwent a coupling reaction with diaryl disulfides in the presence of tri‐n‐butylphosphine when its 6‐amino group was protected by N,N‐dimethylaminomethylidene. The synthesis of 5′‐deoxy‐N3,5′‐cycloisoguanosine ( 6 ) and its 2′,3′‐O‐isopropylidene derivative ( 11 ) were accomplished in excellent yields from isoguanosines ( 3 & 10 ) in the presence of triphenylphospine and carbon tetrachloride in pyridine. Chlorination at the 5′‐position of isoguanosine ( 3 ) with thionyl chloride followed by the aqueous base‐promoted cyclization afforded the same product 6 . The structures were elucidated by spectroscopic analysis including IR, UV, 1‐D and 2‐D NMR. 相似文献
118.
We study the large-time behavior of solutions of viscous conservation laws. It is shown that solutions tend to diffusion waves, which are constructed based on the heat equation and Burgers equation. The convergence is in theL
p
, 1p sense and is obtained as a consequence of theL
2 decay of the difference between the solution and its asymptotic state of diffusion waves.Supported by the National Sciences Council of the Republic of China under the contract NSC-76-0208-M-001-09Supported by NSF under Grant No. DMS-84-01355 相似文献
119.
Bud-Gen Chen Chia Han Lin Chinpiao Chen Boris Hambsch Chi-Liang Chern 《Chromatographia》2013,76(9-10):571-576
Methylglyoxal (MG) is present in the human system. In the cell, MG is degraded by glyoxalase 1 (Glo 1), an enzyme differentially expressed in several mouse models of anxiety-related behavior. It has also been associated with the formation of advanced glycation and lipoxidation end products, contributing to diabetes-related complications. Approaches developed for accurate quantitation of MG in this study include the synthesis of a deuterated MG analog to serve as an internal standard; skillful application of the standard addition protocol (with “reiteration”) to quantitate MG in “blank” samples, allowing the preparation of calibration standards using the same test specimen matrix system; and various pretreatment methods, including extraction and derivatization, to prepare complex brain tissue specimens for gas chromatography–mass spectrometry analysis. Using our method, brain MG levels in high- and low-anxiety-related behavior (HAB and LAB) mice were determined as 5.11 ± 0.89 and 13.05 ± 0.89 μg g?1, respectively. These data supported the conclusion that MG level in brain is negatively correlated with anxiety in mouse models of anxiety-related studies, contributing to better understanding of the molecular mechanisms underlying reported observations. 相似文献
120.
Czechoslovak Mathematical Journal - In 1998, Michael Hirschhorn discovered the 5-dissection formulas of the Rogers-Ramanujan continued fraction R(q) and its reciprocal. We obtain the 5-dissections... 相似文献