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41.
Al-Eideh Basel M.; Al-Refai Ahmad S. A.; Sbeiti Wafaa M. 《IMA Journal of Management Mathematics》2004,15(1):39-51
The Maximum Likelihood estimator is used within a lognormaldiffusion process and closed form analytical solutions are obtained.The monthly CPI forecasts are estimated for the period between1970 and 2002. The quarterly estimates of inflation rates areobtained from monthly forecasts rather than from quarterly data.This has significantly improved the estimates of inflation rates.The model also produced a superior fit as compared to randomwalk and GARCH(p,q)-M models. The adopted approach is foundto be simple, economical and generally suitable for modellingstochastic processes that reflect aggregation over time stemmingfrom many factors, and in which the transition path betweenconsecutive states is relatively smooth. 相似文献
42.
New antineoplastic series of substituted benzothiazolo-β-aminobisphosphonic acids have been developed on the basis of the prospecting potency of the benzothiazole motifs and the aminomethylenebisphosphonate moiety as well as on the prediction of the biological activity utilizing computer program PASS, version 2014-1. Target compounds were obtained in excellent yields (70–90%) via Phospha–Michael-type addition reaction of tetraethyl methylene-1,1-bisphosphonate reagent to a group of Schiff bases incorporating benzothiazole moiety. The reactions proceeded under microwave irradiation, utilizing the advantages of the environment, friendly protocol such as high efficiency, short reaction time, and excellent yields. In consistency with the prospected results, the new NBP acids revealed positive properties against human breast and colon tumor cell lines. Remarkable potency for six lead compounds (out of 12) was observed against breast (MCF7, MDAMB/435, MDAMB/231/ATCC, HS-578T with GI50: 2.05–6.47 μM) and colon (COLO-205, HCT-116, HCC-2998, and SW-620 with GI50: 3.03–7.92 μM) carcinoma cell lines when compared with the positive control Adriamycin (breast, GI50: 3.27–6.64 μM; colon, GI50: 4.09–8.75 μM). Notably, there is a consistency between the prediction and the determined biological results. 相似文献
43.
Wafaa Abdou Yehia Elkhoshnieh Neven Ganoub 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1885-1888
A number of [2,1- b ] fused phosphono substituted-thioxopyranes, -oxadiazines, and -thiazines were obtained from the reactions of the corresponding f -carbonyl methylenes and f -carbonylmonohydrazones with phosphenato-substituted 1,3dithietane 1 . 相似文献
44.
Wafaa M. Abdou M. Refat Mahran Mahmoud M. Sidky Heinrich Wamhoff 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):199-203
Abstract UV-irradiation (δ > 313nm) of O,O-diethyl-O-(4-methyl-2-oxo-2H-1-benzopyran-7-yl)-phosphoro-thioate (Potasan®) la in chloroform and/or methanol with and without singlet oxygen results in the formation of the 2-oxo-2H-1-benzopyran-phosphate 2 the 3,3′-bipotasan dehydrodimer 3, and 7-ethoxy-4-methyl-2-oxo-2H-1-benzopyran 4: the mechanisms of formation, especially for 4 are discussed. 相似文献
45.
Lam T. Bui Jing Liu Axel Bender Michael Barlow Slawomir Wesolkowski Hussein A. Abbass 《Memetic Computing》2011,3(4):271-285
A novel direction-based multi-objective evolutionary algorithm (DMEA) is proposed, in which a population evolves over time along some directions of improvement. We distinguish two types of direction: (1) the convergence direction between a non-dominated solution (stored in an archive) and a dominated solution from the current population; and, (2) the spread direction between two non-dominated solutions in the archive. At each generation, these directions are used to perturb the current parental population from which offspring are produced. The combined population of offspring and archived solutions forms the basis for the creation of both the next-generation archive and parental pools. The rule governing the formation of the next-generation parental pool is as follows: the first half is populated by non-dominated solutions whose spread is aided by a niching criterion applied in the decision space. The second half is filled with both non-dominated and dominated solutions from the sorted remainder of the combined population. The selection of non-dominated solutions for the next-generation archive is also assisted by a mechanism, in which neighborhoods of rays in objective space serve as niches. These rays originate from the current estimate of the Pareto optimal front??s (POF??s) ideal point and emit randomly into the hyperquadrant that contains the current POF estimate. Experiments on two well-known benchmark sets, namely ZDT and DTLZ have been carried out to investigate the performance and the behavior of the DMEA. We validated its performance by comparing it with four well-known existing algorithms. With respect to convergence and spread performance, DMEA turns out to be very competitive. 相似文献
46.
Wafaa S. Hamama Mona E. Ibrahim Hadeer A. Raoof Hanafi H. Zoorob 《Research on Chemical Intermediates》2017,43(11):6259-6291
This review provides a survey of the advances in the methods of formation and chemical reactivity of bicyclic [1,3,4]thiadiazole 5-5 systems containing ring-junction nitrogen over the period from 1989 to the beginning of 2017. 相似文献
47.
Fawzy WM 《The Journal of chemical physics》2006,124(16):164303
In this paper, we present the first correlated ab initio investigations on the ground electronic state of the O(2)-HF complex. Calculations were performed using the CCSD(T) method with the aug-cc-pVDZ and aug-cc-pVTZ basis sets. The results show that there are two equivalent minimum energy hydrogen-bonded structures of planar bent geometry, where the minima correspond to exchange of the oxygen atoms. For each minimum the length of the O-H hydrogen bond is 2.16 A. The best calculated value of D(e) of the equivalent minima is 271 cm(-1). The T-shaped geometry of the complex, with oxygen perpendicular to the axis connecting the center of masses of O(2) and the HF molecule, represents a barrier to tunneling between the equivalent minima. The best estimated value of that barrier height is 217 cm(-1). The linear O-O-HF geometry of the complex represents a saddle point. The calculated geometrical parameters of the minimum energy structure of the complex are in reasonable agreement with the previously reported spectroscopic results. However, results of the current calculations suggest that a full understanding of the fine structures of the observed infrared spectrum of the complex requires the development of an effective Hamiltonian that takes the effects of tunneling into account. 相似文献
48.
49.
Wafaa M. Abdou Mounir A. I. Salem Ashraf A. Sediek 《Monatshefte für Chemie / Chemical Monthly》2003,11(4):1373-1385
Triketoindan-2-oxime reacted readily with ethoxycarbonylmethylene triphenylphosphorane to give mainly the corresponding spiro-pyrrole (38%) along with the fused 1-hydroxydihydropyrrole (14%), whereas the spiro-dimer (29%) was obtained from the reaction of the oxime with methoxycarbonylmethylenetriphenyl phosphorane in addition to the corresponding 1-hydroxydihydropyrrole (31%). Conversely, Wittig products, mono-olefin (52%) and diolefin (<7%) along with the reduced substrate (10%), were observed when the oxime was treated with a cyano ylide. The reactions of the oxime with allyl- and vinyl phosphonium salts proceeded under phase-transfer catalysis to afford fused oxazole (46%) and spiro[2]oxazole (17%), while with the latter the fused 1-hydroxypyrrole (55%) was produced. 相似文献
50.
Wafaa M. Abdou Ashraf A. Sediek Maha D. Khidre 《Monatshefte für Chemie / Chemical Monthly》2008,139(6):617-623
Treatment of triketoindan-2-oxime with α-phosphonyl carbanions in sodium ethanolate solution at reflux temperature led to
a number of the corresponding substituted spiroisooxazole-, fused 1,3-oxazole, and 1,4-oxazine phosphor esters in moderate
to high yields. Mechanisms for the formation of five- and six-membered rings are provided. A comparison of Wittig-Horner and Wittig reagent counterparts in reactions with the oxime is discussed. The various biological properties of selected examples of
the synthesized products were studied.
Correspondence: Wafaa M. Abdou, Chemical Industries Division, National Research Center, Elbohouth St., D-12622 Dokki, Cairo,
Egypt. 相似文献