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121.
Emilio Calvo Esther Gutiérrez Juan Carlos Santos 《International Journal of Game Theory》2000,29(2):177-188
We consider multichoice NTU games, i.e., cooperative NTU games in which players can participate in the game with several
levels of activity. For these games, we define and characterize axiomatically the multichoice consistent value, which is a generalization of the consistent NTU value for NTU games and of the multichoice value for multichoice TU games.
Moreover, we show that this value coincides with the consistent NTU value of a replicated NTU game and we provide a probabilistic
interpretation.
Received: May 1998/Final version: January 2000 相似文献
122.
Sheryl M. Blair Esther C. Kempen Jennifer S. Brodbelt 《Journal of the American Society for Mass Spectrometry》1998,9(10):1049-1059
The quantifiable relationship between the equilibrium solution composition and electrospray (ESI) mass spectral peak intensities of simple host-guest complexes was investigated. Specifically, host-guest complexes of simple crown ethers or glymes with alkali metals and ammonium ions were studied. Comparisons were made between the theoretical concentrations of host-guest complexes derived in solution from known stability constants and the peak intensities for the complexes observed by ESI mass spectrometry (ESI-MS). Two types of complexation experiments were undertaken. First, complexation of a single guest ion, such as an alkali metal, and two crown ethers was studied to evaluate the determination of binding selectivities. Second, complexation of two different guest ions by a single polyether host was also examined. In general, solvation was found to play an integral part in the ability to quantify binding selectivities by ESI-MS. The more similar the solvation energies of the two complexes in the mixture, the more quantifiable their binding selectivities by ESI-MS. In some cases, excellent correlation was obtained between the theoretically predicted selectivity ratios and the ESI mass spectral ratios, in particular when the ESI ratios were adjusted based on evaluation of ESI response factors for the various host-guest complexes. 相似文献
123.
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125.
Seth A. Miller Esther Kim David H. Gray Douglas L. Gin 《Angewandte Chemie (International ed. in English)》1999,38(20):3021-3026
Organic, nanoporous heterogeneous catalysts based on a carboxylate-containing, amphiphilic mesogen catalyze the Knoevenagel condensation (see schematic representation). These networks maintain their order in solution and can be recycled. Enhanced basicity, excellent site accessibility, and substrate size exclusion are features of these nanostructured systems. 相似文献
126.
Songlan Sun Gaia De Angelis Dr. Stefania Bertella Marie J. Jones Dr. Graham R. Dick Prof. Esther Amstad Prof. Jeremy S. Luterbacher 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(5):e202312823
Concerns over the sustainability and end-of-life properties of fossil-derived surfactants have driven interest in bio-based alternatives. Lignocellulosic biomass with its polar functional groups is an obvious feedstock for surfactant production but its use is limited by process complexity and low yield. Here, we present a simple two-step approach to prepare bio-based amphiphiles directly from hemicellulose and lignin at high yields (29 % w/w based on the total raw biomass and >80 % w/w of these two fractions). Acetal functionalization of xylan and lignin with fatty aldehydes during fractionation introduced hydrophobic segments and subsequent defunctionalization by hydrogenolysis of the xylose derivatives or acidic hydrolysis of the lignin derivatives produced amphiphiles. The resulting biodegradable xylose acetals and/or ethers, and lignin-based amphiphilic polymers both largely retained their original natural structures, but exhibited competitive or superior surface activity in water/oil systems compared to common bio-based surfactants. 相似文献
127.
Tim-Oliver Knedel Dr. Esther Ricklefs Carsten Schlüsener Prof. Dr. Vlada B. Urlacher Prof. Dr. Christoph Janiak 《ChemistryOpen》2019,8(11):1337-1344
CgL1 laccase from Corynebacterium glutamicum was encapsulated into the metal-organic framework (MOF) ZIF-8 which was synthesized in a rapid enzyme friendly aqueous synthesis, the fastest in situ encapsulation of laccases reported to date. The obtained enzyme/MOF, i. e. laccase@ZIF-8 composite showed enhanced thermal (up to 70 °C) and chemical (N,N-dimethylformamide) stability, resulting in a stable heterogenous catalyst, suitable for high temperature reactions in organic solvents. Furthermore, the defined structure of ZIF-8 produced a size selective substrate specificity, so that substrates larger than the pore size were not accepted. Thereby, 2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) was used to verify that the enzyme is immobilized inside the MOF versus the outside surface. The enzyme@MOF composite was analyzed by atomic absorption spectroscopy (ASS) to precisely determine the enzyme loading to 2.1 wt%. 相似文献
128.
Copper chloride-catalyzed S-arylation of arenethiols is effected with activated aryl chlorides in neat water by using ethylenediamine as the pair ligand/base. This convenient, environmentally more friendly procedure for the coupling of aryl chlorides allows the arylation between sterically demanding coupling partners. 相似文献
129.
Esther Vizcaino Lourdes ArellanoPilar Fernandez Joan O. Grimalt 《Journal of chromatography. A》2009,1216(25):5045-5051
A sensitive and selective method for the determination of the whole congener distribution of polybromodiphenyl ethers in environmental and biological samples in one single instrumental run is described. The method is based on gas chromatography coupled to low-resolution mass spectrometry in negative ion chemical ionization mode. It allows determination of these compounds at concentration levels lower than 10−14 g. A programmed temperature vaporization injector has been used to ensure maximum compound transfer to the chromatographic column while maintaining low thermal degradation levels of the more brominated congeners. Selectivity was increased by modification of the MS source parameters for optimization of the abundance of the high mass fragment ions. Under optimized condition, good repeatability (1.7–9.1%) and reproducibility (4.1–20%), and low detection limits, ranging between 1.5 and 15 pg ml−1, were obtained. These features afforded reliable quantification of these compounds in snow and human samples at the concentrations in which these compounds are found. 相似文献
130.
Cristina Camarero Inés González-Temprano Asier Gómez-SanJuan Sonia Arrasate Esther Lete Nuria Sotomayor 《Tetrahedron》2009,65(29-30):5787-5798
Conjugate addition reactions of various types of nucleophiles to the γ-lactam unit of dihydroindolizinone systems have been studied. The addition of cuprates, amines or stabilized carbanions requires the activation of the unsaturated bicyclic lactam with a EWG at C-2, while sulfur-stabilized carbanions are reactive enough to add to the unsubstituted lactam. The stereochemical outcome of the conjugate addition reaction depends on the nature of the substituent at the angular position, and the incoming nucleophile. Thus 1,10b-cis or 1,10b-trans diastereomers could be obtained selectively with dr>95:5. The tandem conjugate addition–alkylation also takes place in good yields. These reactions have been applied to the synthesis of enantiopure tetrahydropyrrolo[2,1-a]isoquinolines. 相似文献