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81.
Peter Fechner Oliver Bleher Melanie Ewald Kathrin Freudenberger Dominik Furin Urs Hilbig Felix Kolarov Katrin Krieg Lothar Leidner Goran Markovic Günther Proll Florian Pröll Sabrina Rau Johannes Riedt Barbara Schwarz Patricia Weber Julia Widmaier 《Analytical and bioanalytical chemistry》2014,406(17):4033-4051
This review is focused on methods for detecting small molecules and, in particular, the characterisation of their interaction with natural proteins (e.g. receptors, ion channels). Because there are intrinsic advantages to using label-free methods over labelled methods (e.g. fluorescence, radioactivity), this review only covers label-free techniques. We briefly discuss available techniques and their advantages and disadvantages, especially as related to investigating the interaction between small molecules and proteins. The reviewed techniques include well-known and widely used standard analytical methods (e.g. HPLC-MS, NMR, calorimetry, and X-ray diffraction), newer and more specialised analytical methods (e.g. biosensors), biological systems (e.g. cell lines and animal models), and in-silico approaches. 相似文献
82.
Sandra Grebenteuch Clemens Kanzler Stefan Klaußnitzer Lothar W. Kroh Sascha Rohn 《Molecules (Basel, Switzerland)》2021,26(4)
Lipid oxidation and the resulting volatile organic compounds are the main reasons for a loss of food quality. In addition to typical compounds, such as alkanes, aldehydes and alcohols, methyl ketones like heptan-2-one, are repeatedly described as aroma-active substances in various foods. However, it is not yet clear from which precursors methyl ketones are formed and what influence amino compounds have on the formation mechanism. In this study, the formation of methyl ketones in selected food-relevant fats and oils, as well as in model systems with linoleic acid or pure secondary degradation products (alka-2,4-dienals, alken-2-als, hexanal, and 2-butyloct-2-enal), has been investigated. Elevated temperatures were chosen for simulating processing conditions such as baking, frying, or deep-frying. Up to seven methyl ketones in milk fat, vegetable oils, and selected model systems have been determined using static headspace gas chromatography-mass spectrometry (GC-MS). This study showed that methyl ketones are tertiary lipid oxidation products, as they are derived from secondary degradation products such as deca-2,4-dienal and oct-2-enal. The study further showed that the position of the double bond in the precursor compound determines the chain length of the methyl ketone and that amino compounds promote the formation of methyl ketones to a different degree. These compounds influence the profile of the products formed. As food naturally contains lipids as well as amino compounds, the proposed pathways are relevant for the formation of aroma-active methyl ketones in food. 相似文献
83.
Topin V Delenne JY Radjai F Brendel L Mabille F 《The European physical journal. E, Soft matter》2007,23(4):413-429
Cemented granular materials (CGMs) consist of densely packed solid particles and a pore-filling solid matrix sticking to the
particles. We use a sub-particle lattice discretization method to investigate the particle-scale origins of strength and failure
properties of CGMs. We show that jamming of the particles leads to highly inhomogeneous stress fields. The stress probability
density functions are increasingly wider for a decreasing matrix volume fraction, the stresses being more and more concentrated
in the interparticle contact zones with an exponential distribution as in cohesionless granular media. Under uniaxial loading,
pronounced asymmetry can occur between tension and compression both in strength and in the initial stiffness as a result of
the presence of bare contacts (with no matrix interposed) between the particles. Damage growth is analyzed by considering
the evolution of stiffness degradation and the number of broken bonds in the particle phase. A brutal degradation appears
in tension as a consequence of brittle fracture in contrast to the more progressive nature of damage growth in compression.
We also carry out a detailed parametric study in order to assess the combined influence of the matrix volume fraction and
particle-matrix adherence. Three regimes of crack propagation can be distinguished corresponding to no particle damage, particle
abrasion and particle fragmentation, respectively. We find that particle damage scales well with the relative toughness of
the particle-matrix interface with respect to the particle toughness. This relative toughness is a function of both matrix
volume fraction and particle-matrix adherence and it appears therefore to be the unique control parameter governing transition
from soft to hard behavior. 相似文献
84.
Simon Muench René Burges Alexandra Lex-Balducci Johannes C. Brendel Michael Jäger Christian Friebe Andreas Wild Ulrich S. Schubert 《Journal of polymer science. Part A, Polymer chemistry》2021,59(6):494-501
Despite intensive scientific efforts on the development of organic batteries, their full potential is still not being realized. The individual components, such as electrode materials and electrolytes, are in most cases developed independently and are not adjusted to each other. In this context, we report on the performance optimization of a full-organic solid-state battery system by the mutual adaptation of the electrode materials and an ionic liquid (IL)-based gel polymer electrolyte (GPE). The formulation of the latter was designed for a one-step manufacturing approach and can be applied directly to the electrode surface, where it is UV-cured to yield the GPE without further post-treatment steps. Herein, a special focus was placed on the applicability in industrial processes. A first significant capacity increase was achieved by the incorporation of the IL into the electrode composite. Furthermore, the GPE composition was adapted applying acrylate- and methacrylate-based monomers and combinations thereof with the premise of a fast curing step. Furthermore, the amount of IL was varied, and all combinations were evaluated for their final performance in cells. The latter variation revealed that a high ionic conductivity is not the only determining factor for a good cell performance. Next to a sufficient conductivity, the interaction between electrode and electrolyte plays a key role for the cell performance as it enhances the accessibility of the counter ions to the redox-active sites. 相似文献
85.
Matthias Brendel Carolin Braun Dr. Frank Rominger Prof. Dr. Peter Hofmann 《Angewandte Chemie (International ed. in English)》2014,53(33):8741-8745
For a long time d10‐ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ‐donating ligands leading to electron‐rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis‐NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5‐cyclooctadiene)nickel(0) and ‐platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal‐planar bis‐NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C? C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond‐activation chemistry and catalysis. 相似文献
86.
87.
A capillary zone electrophoretic method with UV-scanning detection for the separation and identification of both free ligands and metal species is presented. The electrophoretic behavior of naturally occurring binding partners such as organic acids and amino acids was studied and compared with their metal-complexes. Copper(II) complexes of citrate and amino acids showed decreased electrophoretic mobilities and altered UV spectra. The optimized method was validated on ultrafiltered cow's milk and human milk samples. In cow's milk six low molecular weight substances, including citrate, orotate, and hippurate, could be separated. Metal supplementation with Cu(II), Ni(II), or Zn(II) decreased not only the citrate peak but also the orotate signal and in the case of copper(II) supplementation a new signal for the copper(II)-citrate complex appeared. In human milk samples various amino acids such as glutamate, phenylalanine, tyrosine, and tryptophan could be identified besides citrate. The electrophoretic mobilites and peak areas of the amino acids were also influenced by the metal supplementation. 相似文献
88.
89.
In the search for organic ferromagnets polymers with a conjugated backbone and pendant persistent radicals are one route of interest. The synthesis of poly[4-(4-ethynylphenyl)-2′,4′,6′-trinitro-2,6-diphenyldiphenylamine] (p-3) and poly[4-(3-ethynylphenyl)-2′,4′,6′-trinitro-2,6-diphenyldiphenylamine] (m-3) as precursors of polyradicals are described. A dinuclear rhodium cyclooctadiene chloride complex as polymerization catalyst was used to yield polymers with molecular weights (gel-permeation chromatography) of 100 000 for m-3 and 210 000 for p-3 . 相似文献
90.