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1.
The use of novel water-in-oil microemulsions in microemulsion electrokinetic chromatography 总被引:3,自引:0,他引:3
We describe the novel use of water-in-oil (W/O) microemulsions to achieve unique separations in microemulsion electrokinetic chromatography (MEEKC). The choice and concentration of the buffer type, surfactant and co-surfactant were all examined and optimized. Separations of a range of neutral and acidic analytes was shown to be markedly different to that obtained by (oil-in-water) O/W MEEKC. Neutral solutes are separated by virtue of their solubility (log P) values in O/W MEEKC with the more water-insoluble solutes migrating last. This separation process does not occur in W/O, as neutral solutes are not separated in order of log P. 相似文献
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Ridley CP Bergquist PR Harper MK Faulkner DJ Hooper JN Haygood MG 《Chemistry & biology》2005,12(3):397-406
Four species of marine sponges (Phylum Porifera, Order Dictyoceratida), which contain the filamentous cyanobacterial symbiont Oscillatoria spongeliae, were collected from four locations in Palau. The halogenated natural products associated with the symbiont were characterized from each sample, revealing that each species contained either chlorinated peptides, brominated diphenyl ethers, or no halogenated compounds. Analysis of the host sponges and the symbionts indicated that each species of sponge contained a distinct strain of morphologically similar cyanobacteria. Although cospeciation may be present in this group, we have identified that at least one host switching event has occurred in this symbiosis. Only the strain of O. spongeliae in the sponge containing the chlorinated compounds possessed genes involved in the biosynthesis of chlorinated leucine precursors, indicating that the chemical variation observed in these animals has a genetic foundation. 相似文献
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D. O. Krivenkov D. A. Artemenkov V. Bradnova S. Vokál P. I. Zarubin I. G. Zarubina N. V. Kondratieva A. I. Malakhov A. A. Moiseenko G. I. Orlova N. G. Peresadko N. G. Polukhina P. A. Rukoyatkin V. V. Rusakova V. R. Sarkisyan R. Stanoeva M. Haiduc S. P. Kharlamov 《Physics of Atomic Nuclei》2010,73(12):2103-2109
Results on the coherent dissociation of relativistic 9C nuclei in a nuclear track emulsion are described. These results include the charge topology and kinematical features of final states. Events of 9C → 33He coherent dissociation are identified. 相似文献
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A. I. Klimov K. N. Kozlov E. A. Meleshko I. E. Ostashev V. A. Grigoriev V. A. Kaplin V. A. Loginov N. V. Kondratieva V. A. Veselovsky 《Physics of Atomic Nuclei》2009,72(2):286-292
The design and special features of the main units of high-speed electronics for the trigger subsystem of the T0 detector of the ALICE experiment are considered. Its characteristic time resolution is 50 ps. The dead time does not exceed 25 ns. 相似文献
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Öznur Yaşar Danny Dyer David A. Pike Margo Kondratieva 《Discrete Applied Mathematics》2009,157(8):1913-1923
In traditional edge searching one tries to clean all of the edges in a graph employing the least number of searchers. It is assumed that each edge of the graph initially has a weight equal to one. In this paper we modify the problem and introduce the Weighted Edge Searching Problem by considering graphs with arbitrary positive integer weights assigned to its edges. We give bounds on the weighted search number in terms of related graph parameters including pathwidth. We characterize the graphs for which two searchers are sufficient to clear all edges. We show that for every weighted graph the minimum number of searchers needed for a not-necessarily-monotonic weighted edge search strategy is enough for a monotonic weighted edge search strategy, where each edge is cleaned only once. This result proves the NP-completeness of the problem. 相似文献
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Oleg Golubitsky Marina Kondratieva Alexey Ovchinnikov Agnes Szanto 《Journal of Algebra》2009,322(11):3852
We give the first known bound for orders of differentiations in differential Nullstellensatz for both partial and ordinary algebraic differential equations. This problem was previously addressed in [A. Seidenberg, An elimination theory for differential algebra, Univ. of California Publ. in Math. III (2) (1956) 31–66] but no complete solution was given. Our result is a complement to the corresponding result in algebraic geometry, which gives a bound on degrees of polynomial coefficients in effective Nullstellensatz [G. Hermann, Die Frage der endlich vielen Schritte in der Theorie der Polynomideale, Math. Ann. 95 (1) (1926) 736–788; E.W. Mayr, A.W. Meyer, The complexity of the word problems for commutative semigroups and polynomial ideals, Adv. Math. 46 (3) (1982) 305–329; W.D. Brownawell, Bounds for the degrees in the Nullstellensatz, Ann. of Math. 126 (3) (1987) 577–591; J. Kollár, Sharp effective Nullstellensatz, J. Amer. Math. Soc. 1 (4) (1988) 963–975; L. Caniglia, A. Galligo, J. Heintz, Some new effectivity bounds in computational geometry, in: Applied Algebra, Algebraic Algorithms and Error-Correcting Codes, Rome, 1988, in: Lecture Notes in Comput. Sci., vol. 357, Springer, Berlin, 1989, pp. 131–151; N. Fitchas, A. Galligo, Nullstellensatz effectif et conjecture de Serre (théorème de Quillen–Suslin) pour le calcul formel, Math. Nachr. 149 (1990) 231–253; T. Krick, L.M. Pardo, M. Sombra, Sharp estimates for the arithmetic Nullstellensatz, Duke Math. J. 109 (3) (2001) 521–598; Z. Jelonek, On the effective Nullstellensatz, Invent. Math. 162 (1) (2005) 1–17; T. Dubé, A combinatorial proof of the effective Nullstellensatz, J. Symbolic Comput. 15 (3) (1993) 277–296].This paper is dedicated to the memory of Eugeny Pankratiev, who was the advisor of the first three authors at Moscow State University. 相似文献
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O. D. Golubitsky M. V. Kondratieva A. I. Ovchinnikov 《Journal of Mathematical Sciences》2009,163(5):515-522
The Ritt problem asks if there is an algorithm that decides whether one prime differential ideal is contained in another one
if both are given by their characteristic sets. We give several equivalent formulations of this problem. In particular, we
show that it is equivalent to testing whether a differential polynomial is a zero divisor modulo a radical differential ideal.
The technique used in the proof of this equivalence yields algorithms for computing a canonical decomposition of a radical
differential ideal into prime components and a canonical generating set of a radical differential ideal. Both proposed representations
of a radical differential ideal are independent of the given set of generators and can be made independent of the ranking. 相似文献