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61.
Néstor M. Carballeira David Sanabria Norma L. Ayala Clarisa Cruz 《Tetrahedron letters》2004,45(19):3761-3763
A stereoselective synthesis for the (5Z,9Z)-14-methyl-5,9-pentadecadienoic acid and the monounsaturated analog (Z)-14-methyl-9-pentadecenoic acid was accomplished in six to seven steps where double alkyne coupling was the key step. This synthesis will facilitate the study of the topoisomerase I inhibitory profile of this important class of fatty acids. 相似文献
62.
Ricardo J. C. Lima Jose M. Sasaki Alejandro P. Ayala Paulo T. C. Freire Josue Mendes‐Filho Francisco E. A. Melo Javier Ellena Sauli Santos Jr 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(7):i67-i70
The preparation and structures of caesium lithium sulfate, Cs1.15Li2.85(SO4)2, and caesium lithium rubidium sulfate, Cs0.90Li2.88Rb0.22(SO4)2, are described and discussed in the context of simple and double sulfate polymorphism. The latter structure is related to the former through the substitution of Rb for Cs. In both crystals, the sulfate ions occupy two non‐equivalent sites, but the ions are disordered in Cs1.15Li2.85(SO4)2. 相似文献
63.
O. E. Ayala D. Lardizábal A. Reyes M. I. Rosales J. A. Matutes A. González Arias 《Journal of Thermal Analysis and Calorimetry》2000,59(3):943-949
Expressions for calculating the cation vacancy contents of MnZn ferrites from thermogravimetric curves are presented together
with some experimental data. In a single-phase MnZn ferrite synthesized by conventional ceramic procedures, the O2 evolution accompanying ferrite formation follows the formal equation.
Mn2+
σα Znσβ Fe3+
2σ(1–γ) [V ]σ/4(1–2γ) O4 =σ'/σ Mn2+
σ(α–2ϕ) Znσβ Fe2+
2σθ Mn3+
2σϕ Fe3+
2σ(1–γ–θ) [V ]σ/4(1–2γ–3ϕ) O4 +σ'φ/2O2 (g)
where α and β denote the MnO and ZnO mole fractions in the primary mixture γ=α+β, θ and ϕ depend on the quantities of Fe2+ and Mn3+ formed, respectively, φ=θ–ϕ and σ'/σ is a function of the former parameters. Even though the relative amounts of Fe2+ /Fe3+ and Mn2+ /Mn3+ remain uncertain, the vacancy content [V ] of the ferrite can be determined because it depends on φ alone, which is related to the change in mass of the sample as
the synthesis takes place through the equation
φ=(1.5–γ) μβ /μO2 (1–m
f /m
i )
Here, m
i and m
f are the masses of the sample before and after O2 evolution, μB is the formula mass of the ferrite and μO2 is the O2 molar mass. Practically vacancy-free single-phase MnZn ferrite samples were obtained by sintering in air at 1250°C and cooling
in pure N2 .
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
64.
This paper is an elementary introduction to the theory of moduli spaces of curves and maps. As an application to enumerative geometry, we show how to count the number of bitangent lines to a projective plane curve of degree d by doing intersection theory on moduli spaces. 相似文献
65.
Ayala Mashiah-Yaakovi 《International Journal of Game Theory》2009,38(2):169-181
Stopping games (without simultaneous stopping) are sequential games in which at every stage one of the players is chosen,
who decides whether to continue the interaction or stop it, whereby a terminal payoff vector is obtained. Periodic stopping
games are stopping games in which both of the processes that define it, the payoff process as well as the process by which
players are chosen, are periodic and do not depend on the past choices. We prove that every periodic stopping game without
simultaneous stopping, has either periodic subgame
perfect ϵ-equilibrium or a subgame perfect 0-equilibrium in pure strategies.
This work is part of the master thesis of the author done under the supervision of Prof. Eilon Solan. I am thankful to Prof.
Solan for his inspiring guidance. I also thank two anonymous referees of the International Journal of Game Theory for their
comments. 相似文献
66.
R. Ayala M. Cá rdenas F. F. Lasheras A. Quintero 《Proceedings of the American Mathematical Society》2005,133(5):1527-1535
A finitely presented group is said to be properly -realizable if there exists a compact -polyhedron with and whose universal cover has the proper homotopy type of a (p.l.) -manifold with boundary. In this paper we show that, after taking wedge with a -sphere, this property does not depend on the choice of the compact -polyhedron with . We also show that (i) all -ended and -ended groups are properly -realizable, and (ii) the class of properly -realizable groups is closed under amalgamated free products (HNN-extensions) over a finite cyclic group (as a step towards proving that -ended groups are properly -realizable, assuming -ended groups are).
67.
Alcalde E Ayala C Dinarès I Mesquida N Sánchez-Ferrando F 《The Journal of organic chemistry》2001,66(7):2281-2290
A convergent "5 + 1" and "5 + 3" synthetic strategy allowed the synthesis of the first examples of bis-betaines 2 and 3, a prototype of phanes that incorporate heterocyclic betaines. The structure of the quadrupolar macrocyclic systems 2 and 3 together with the dicationic [1(6)]- and [1(8)] meta-heterophane precursors 5*2X and 6*2X were examined by spectroscopy using 1H and 13C NMR techniques together with 1H-DNMR studies and electrospray ionization mass spectrometry. 相似文献
68.
69.
70.
Palmero EI Kalakun L Schüler-Faccini L Giugliani R Regla Vargas F Rocha JC Ashton-Prolla P 《Community genetics》2007,10(2):110-119
In Brazil, genetic counseling is usually available in university-affiliated medical genetics services located in tertiary centers that provide cancer diagnosis and treatment. The present study aims to describe the structure and characteristics of three cancer genetic services in Brazilian public health care hospitals and discuss alternatives for the identification and prevention of hereditary cancer syndromes in developing countries. The three services presented here are similar in their structure, routine procedures for cancer risk estimation and criteria for the indication of genetic testing. They all demand that genetic counseling be an essential part of the cancer risk evaluation process, before and after cancer predisposition testing. However, when high-risk patients are identified, all services describe difficulties in the access and continuity of genetic and medical services to the patient and his/her at-risk relatives. The services differ in the type of population served, reflecting distinct referral guidelines. This study emphasizes the importance of the creation of new cancer genetic services in other Brazilian regions and the necessity for establishing a collaborative network to facilitate the diagnosis and research of cancer genetic syndromes. 相似文献