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991.
For a set system M=(Mv)v∈V indexed by the elements of a finite set V, the intersection betweenness B(M) induced by M consists of all triples (u,v,w)∈V3 with Mu∩Mw⊆Mv. Similarly, the strict intersection betweenness Bs(M) induced by M consists of all triples (u,v,w)∈B(M) such that u, v, and w are pairwise distinct. The notion of a strict intersection betweenness was introduced by Burigana [L. Burigana, Tree representations of betweenness relations defined by intersection and inclusion, Math. Soc. Sci. 185 (2009) 5-36]. We provide axiomatic characterizations of intersection betweennesses and strict intersection betweennesses. Our results yield a simple and efficient algorithm that constructs a representing set system for a given (strict) intersection betweenness. We study graphs whose strict shortest path betweenness is a strict intersection betweenness. Finally, we explain how the algorithmic problem related to Burigana’s notion of a partial tree representation can be solved efficiently using well-known algorithms. 相似文献
992.
993.
J.L. Capelo R.J. Carreira L. Fernandes C. Lodeiro H.M. Santos J. Simal-Gandara 《Talanta》2010,80(4):1476-1078
Nowadays isotopic 18O-labeling of peptides has recalled the attention of researchers due to its simplicity of application and high versatility for proteomics studies. Protein quantification, differential peptide mass mapping, studies regarding proteins overexpressed or underexpressed, or the searching of biomarkers can be accomplished by using 18O-labeling. In this critical review we comment on the different ways in which 18O-labeling can be done, highlighting the key parameters of the different sample treatments to obtain a reliable and reproducible labeling. In addition we describe and compare the latest improvement in terms of sample treatment that allows to reduce the handling and to increase the throughput for this sample treatment. Finally, we hypothesize on the future trends of these methods under the light of the new technological advances to speed protein cleavage. 相似文献
994.
Manuel A.V. Ribeiro da Silva Ana I.M.C. Lobo Ferreira Fabrice M. Maciel 《The Journal of chemical thermodynamics》2010,42(2):220-224
The present work is part of a research program on the energetics of the linear 4-n-alkoxybenzoic acids, aiming the study of the enthalpic effect of the introduction of an alkoxy chain in the position 4- of the benzoic acid ring. In this work, we present the results of the thermochemical research on 4-n-alkoxybenzoic acids with the alkoxy chain length n = 2, 4, and 8.The standard () molar enthalpy of formation of crystalline 4-ethoxybenzoic acid, 4-butoxybenzoic acid, and 4-(octyloxy)benzoic acid was measured, at T = 298.15 K, by static-bomb calorimetry. These values, combined with the values of standard molar enthalpies of sublimation, were used to derive the standard molar enthalpies of formation in the gaseous phase.
4-Alkoxybenzoic acid | |||
---|---|---|---|
4-Ethoxybenzoic acid | 4362.7 ± 1.3 | 605.5 ± 1.8 | 482.2 ± 2.0 |
4-Butoxybenzoic acid | 5677.3 ± 2.0 | 647.1 ± 2.5 | 518.1 ± 2.6 |
4-(Octyloxy)benzoic acid | 8269.0 ± 3.3 | 767.9 ± 3.9 | 604.9 ± 4.1 |