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121.
122.
Daniela Nedeltcheva Vanya Kurteva Ivanka Topalova 《Rapid communications in mass spectrometry : RCM》2010,24(6):714-720
The tautomeric constants of a series of azo dyes were estimated in the gas phase by using electron ionization mass spectrometry. It was shown that the relative amount of the keto tautomer increases from 4‐phenylazo‐1‐phenol to 4‐phenylazo‐anthracen‐1‐ol, thus confirming the quantum‐chemical predictions. The existence of the enol tautomer of 4‐phenylazo‐anthracen‐1‐ol is shown for the first time by mass spectrometry in the gas phase. This finding is supported by flash photolysis measurements in solution. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
123.
Gehanne S Cecconi D Carboni L Righetti PG Domenici E Hamdan M 《Rapid communications in mass spectrometry : RCM》2002,16(17):1692-1698
We describe a simple approach for the relative quantification of individual proteins within a mixture. The method is based on the differential labelling of the mixtures by use of a commercially available acrylamide and deuterium-labelled [2,3,3'-d(3)]-acrylamide to alkylate proteins prior to two-dimensional (2-D) gel electrophoresis. The tryptic digests of the separated proteins were subjected to reflector matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis and the relative peak heights of cysteine-containing peptides were used to quantify their precursor proteins. This approach was tested for the relative quantification of proteins within an artificial mixture of standard proteins and for proteins observed in a 2-D map of rat serum. A good correlation was found between the measured ratios derived from MALDI-TOF data and those theoretically calculated prior to 2-D analysis via known mixing ratios of the two alkylating reagents. The described procedure has proved to be effective for comparative measurements of protein abundances within the investigated mixtures. 相似文献
124.
The direct formation of alpha-methylene-beta-amino acid derivatives is achieved using the aza version of the Baylis-Hillman protocol. The products are readily formed in a three-component one-pot reaction between arylaldehydes, sulfonamides, and alpha,beta-unsaturated carbonyl compounds. The reaction is efficiently catalyzed by titanium isopropoxide and 2-hydroxyquinuclidine in the presence of molecular sieves. The protocol allows for structural variation of the substrates, tolerating electron-poor and electron-rich arylaldehydes and various Michael acceptors. 相似文献
125.
126.
Carolina Muscoli Daniela Salvemini Donatella Paolino Michelangelo Iannone Ernesto Palma Antonio Cufari Domenicantonio Rotiroti Federico Carlo Perno Stefano Aquaro Vincenzo Mollace 《BMC neuroscience》2002,3(1):13-8
Background
Oxidative stress has shown to contribute in the mechanisms underlying apoptotic cell death occuring in AIDS-dementia complex. Here we investigated the role of peroxynitrite in apoptosis occurring in astroglial cells incubated with supernatants of HIV-infected human primary macrophages (M/M). 相似文献127.
Monge ME Bulone D Giacomazza D Negri M Bernik DL 《Combinatorial chemistry & high throughput screening》2004,7(4):337-344
Multicomponent essential oils Tagetes Minuta and Poleo as well as pure limonene were encapsulated in Tween doped-high methoxylated pectin gels. Optical microscopy reveals that the obtained gels containing limonene consisted in a highly heterogeneous oil-in-water emulsion stabilised by the gelled medium. The influence of limonene encapsulation in pectin gelation kinetics and the gel structural properties were followed by dynamic rheological measurements. An electronic nose device developed in our laboratory was used to follow the flavour release of the three systems in order to discriminate the samples according to the main components released to the headspace. PCA and Neural Network Analysis allowed us to discriminate Tagetes Minuta from Poleo due to the difference in their limonene content. It is remarkable that the fingerprints of encapsulated complex mixtures differ from those obtained for the non-encapsulated oils, showing a preferential release of some components. In the case of limonene, the effect of the encapsulated concentration on the detected odour was also studied. 相似文献
128.
In this paper, we prove higher integrability results for the gradient of the solutions of some elliptic equations with degenerate
coercivity whose prototype is
where for example, a(x,u)=(1+|u|)−θ with θ ∈ (0,1). We study the same problem for minima of functionals closely related to the previous equation. 相似文献
129.
130.
F. Bonechi R. Giachetti E. Sorace M. Tarlini 《Journal of Mathematical Sciences》2001,104(3):1105-1110
We apply the techniques of induced representations to study the one-dimensional quantum Galilei group. We prove the existence of a quasi-invariant measure on the homogeneous space and of the corresponding square integrable functions. First, the unitary property of the induced representations is studied in the physically meaningful case of a real quantum parameter where the involution is nonstandard. The behavior in the complex case, where (* S)2=id, is similar to the classical one. Bibliography: 5 titles. 相似文献