We show that the complex link of a large class of space germs (X,x0) is characterized by its “simplicity”, among the Milnor fibres of functions with isolated singularity on X. This amounts to the minimality of the Milnor number, whenever this number is defined. Such a phenomenon has been first pointed out in case (X,x0) is an isolated hypersurface singularity, by Teissier (Cycles évanescents, sections planes et conditions de Whitney, in: Singularités à Cargèse 1972, Asterisque, Nos. 7 et 8, Soc. Math. France, Paris, 1973, pp. 285-362). 相似文献
The current work presents an objective overview of the impact of one important heterocyclic structure, the pyrazole ring, in the development of anti-proliferative drugs. A set of 1551 pyrazole derivatives were extracted from the National Cancer Institute (NCI) database, together with their growth inhibition effects (GI%) on the NCI’s panel of 60 cancer cell lines. The structures of these derivatives were analyzed based on the compounds’ averages of GI% values across NCI-60 cell lines and the averages of the values for the outlier cells. The distribution and the architecture of the Bemis–Murcko skeletons were analyzed, highlighting the impact of certain scaffold structures on the anti-proliferative effect’s potency and selectivity. The drug-likeness, chemical reactivity and promiscuity risks of the compounds were predicted using AMDETlab. The pyrazole ring proved to be a versatile scaffold for the design of anticancer drugs if properly substituted and if connected with other cyclic structures. The 1,3-diphenyl-pyrazole emerged as a useful scaffold for potent and targeted anticancer candidates. 相似文献
A high-precision exact-matching quadruple isotope dilution method (ID4MS) was employed for the quantitation of nitrate in an air-dried spinach powder Certified Reference Material (CRM). The analyte was extracted in hot water following addition of 15NO\({}_{3}^{-}\) internal standard. The blend was then treated with sulfamic acid to remove nitrite and with triethyloxonium tetrafluoroborate to promote aqueous conversion of nitrate into volatile EtONO2. The derivative was analyzed by headspace GC–MS with 3-min elution time. The method performance was validated with a series of tests which demonstrated adequate selectivity and ruggedness. This method supported the development of novel SPIN-1 CRM giving a modest contribution to its uncertainty (uchar = 0.85%). With respect to previous attempts, the SPIN-1 was proven stable, homogeneous (uhom = 0.44%), and suitable for spinach monitoring under EU regulations. On dried basis, the nitrate content of SPIN-1 was found to be 22.53 ± 0.43 mg/g (Uc = 1.9%, k = 2). The material was also used in an inter-laboratory study where four laboratories employed a total of ten measurement methods.
Trioxane was copolymerized with small amounts of dioxolane in benzene in the presence of a boron trifluoride:a crylonitrile complex as initiator. The kinetics of reactions was expressed in terms of topoenergetic principles. The copolymerizations had no induction periods and the maximum reaction rate was found proportional to the square of both the initiator and monomers concentrations. A zwitterionic mechanism is suggested for initiation. The activation energy for the system with 5% dioxolane was determined as 18.3 kcal/mol. The melting behavior of the copolymers is briefly discussed as a function of the dioxolane initial content, and is indicative of the amorphous-crystalline coupling phenomenon. The copolymers with ~ 5% dioxolane are thermostable in air up to 250%deg; and are recommended for practical purposes. 相似文献
This article describes a new efficient synthesis of drim-7,9(11)-diene and its hydroxylated derivates from drim-8-en-7-one. Reduction of this ketone with NaBO4 in the presence of CeCl3 · 7H2O afforded regio- and stereoselectively drim-8-en-7β-ol in a high yield. Its dehydration with H2SO4 under mild conditions led to drim-7,9(11)-diene. Noncatalytic oxidation of drim-7,9(11)-diene with OsO4 and the catalytic oxidation with the pair OsO4–NMO gave, in a high yield, depending on conditions, driman-7β,8β,9α,11-tetraol or its mixture with drim-7-en-9α,11-diol and drim-9(11)-en-7α,8α-diol. Under optimal conditions the total yield of these diols reached 89%. The separate, noncatalytic oxidation of drim-7-en-9α,11-diol and of drim-9(11)-en-7α,8α-diol with OsO4 afforded driman-7α,8α,9α,11-tetraol. 相似文献