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141.
Ana Torvisco Anna Y. O’Brien Karin Ruhlandt-Senge 《Coordination chemistry reviews》2011,255(11-12):1268-1292
This article provides a concise summary of alkaline earth metal nitrogen chemistry. This important area of s-block metal chemistry is shedding important light on the recent development of alkaline earth metal chemistry, as the preparation of the target compounds utilizes a large variety of synthetic methodology. Further, the compounds have been utilized in a range of applications, including polymerization initiation, catalysis, as solid-state precursors, and even high energy materials. 相似文献
142.
Nagy K Redeuil K Williamson G Rezzi S Dionisi F Longet K Destaillats F Renouf M 《Journal of chromatography. A》2011,1218(3):491-497
There is a substantial amount of published literature on the bioavailability of various coffee components including the most abundant metabolites, caffeic and ferulic acids. Surprisingly, to date, the appearance of dimethoxycinnamic acid derivatives in humans has not been reported despite the fact that methylated form of catechol-type polyphenols could help maintain, modify or even improve their biological activities. This study reports an LC-MS method for the detection of dimethoxycinnamic acid in human plasma after treatment with an esterase. Liquid chromatography, including the combination of methanol and acetonitrile as organic eluent, was optimized to resolve all interferences and enable reliable detection and identification of 3,4-dimethoxycinnamic and 3,4-dimethoxy-dihydrocinnamic acids. In addition to the good mass accuracy achieved (better than 5 ppm), tandem mass spectrometric and co-chromatography experiments further confirmed the identity of the compounds. The optimized method was applied to analyze samples obtained immediately, 1 and 10 h after coffee ingestion. The results show that in particular 3,4-dimethoxycinnamic acid appears in high abundance (~380 nM at 60 min) in plasma upon coffee intake, indicating that it is important to consider these derivatives in future bioavailability and bioefficacy studies. 相似文献
143.
An effective medium theory is employed to derive a simple qualitative model of a pattern forming chemical reaction in a microemulsion. This spatially heterogeneous system is composed of water nanodroplets randomly distributed in oil. While some steps of the reaction are performed only inside the droplets, the transport through the extended medium occurs by diffusion of intermediate chemical reactants as well as by collisions of the droplets. We start to model the system with heterogeneous reaction-diffusion equations and then derive an equivalent effective spatially homogeneous reaction-diffusion model by using earlier results on homogenization in heterogeneous reaction-diffusion systems [S.Alonso, M.Ba?r, and R.Kapral, J. Chem. Phys. 134, 214102 (2009)]. We study the linear stability of the spatially homogeneous state in the resulting effective model and obtain a phase diagram of pattern formation, that is qualitatively similar to earlier experimental results for the Belousov-Zhabotinsky reaction in an aerosol OT (AOT)-water-in-oil microemulsion [V.K.Vanag and I.R.Epstein, Phys. Rev. Lett. 87, 228301 (2001)]. Moreover, we reproduce many patterns that have been observed in experiments with the Belousov-Zhabotinsky reaction in an AOT oil-in-water microemulsion by direct numerical simulations. 相似文献
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146.
Janiak J Piculell L Olofsson G Schillén K 《Physical chemistry chemical physics : PCCP》2011,13(8):3126-3138
The aim of this work was to study intermolecular interactions in systems containing charged polyion (polyacrylate, PA(-)), charged surfactant (C(16)TA(+)) and nonionic surfactant (C(12)E(5) or C(12)E(8)). To achieve this we have created four different phase diagrams using two different so-called complex salts, C(16)TAPA(25) and C(16)TAPA(6000), both consisting of positively charged surfactant (C(16)TA(+)) with polyacrylate (PA(-)) as counterions (no simple salt). The difference between the salts is the length of the polyion (25 or 6000 monomers). Both are insoluble in water. The results revealed that decreasing polyion length and increasing the PEO chain length of the nonionic surfactant were important factors for increasing the solubility of the complex salt. We also found that the curvature effects are quite small at low water content when gradually exchanging C(12)E(8) for either one of the complex salts while there is a gradual change in curvature for the systems containing C(12)E(5). Another interesting observation was the possibility for relatively large amounts of complex salt to be incorporated into a V(1) (Ia3d, bicontinuous) phase in the C(12)E(8)-containing systems. This gives rise to several questions regarding arrangements and dynamics of the polyion in this phase. In the dilute regime several different liquid crystalline phases can coexist with a dilute liquid phase containing the nonionic surfactant. 相似文献
147.
Mathias Hopfinger Karin Lux Felix Schubert Andreas Kornath 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(12):m400-m402
The title salt, (C2H8NO3S)[SbF6], which contains the protonated form of taurine (2‐aminoethanesulfonic acid), was synthesized in anhydrous hydrofluoric acid and recrystallized as colourless block‐shaped crystals from liquid SO2. In the solid state, a three‐dimensional network is observed. This is formed by intra‐ and intermolecular N—H...O, N—H...F and O—H...F hydrogen bonds. 相似文献
148.
The hydraulic and mass transfer characteristic of a novel grid-structured plastic packing is presented. The geometry of this
structured packings differ substantially from conventional corrugated structured packings resulting in an open structure which
enables a free exchange of vapour and liquid also in horizontal direction. The hydraulic performance has been measured by
air–water experiments in a 440 mm diameter column, the mass transfer characteristic has been determined with the absorption
system ammonia–air–water. Is is shown that the grid-structured plastic packing is highly efficient, particularly in terms
of the hydraulic capacity compared with random plastic packings. Beside this, the main advantage of the packing is the easy
handling and installation as well as the low investment costs compared to the well-known conventional corrugated structured
packings. 相似文献
149.
Karin Cvetko-Vah 《Algebra Universalis》2011,66(1-2):99-113
Skew lattices are a non-commutative generalization of lattices. In the past 20?years, several varieties of skew lattices have been introduced. In the present paper we study the variety of strongly symmetric skew lattices. 相似文献
150.
G. E. Milkereit S. S. H. Gerber Karin Jankowski A. Terjung R. R. Schmidt V. Vill 《Journal of Thermal Analysis and Calorimetry》2005,82(2):471-475
Summary A set of Y-shaped and Siamese-twin shaped carbohydrate based glycolipids was investigated using polarising microscopy. The
structure was changed from the normal type (1 head, two chains) to complex inverted structures (2 heads outside 1 to 3 chains
in the middle part). The carbohydrate headgroup was changed from mono- to disaccharide; also the alkyl chain length was varied
systematically. The compounds displayed different thermotropic mesophases (Smectic A phases, columnar phases and cubic phases)
depending on the type of carbohydrate headgroup and the alkyl chain length. 相似文献