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排序方式: 共有740条查询结果,搜索用时 156 毫秒
21.
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
22.
Andr Delavault Katarina Ochs Olga Gorte Christoph Syldatk Erwann Durand Katrin Ochsenreither 《Molecules (Basel, Switzerland)》2021,26(2)
Glycolipids are non-ionic surfactants occurring in numerous products of daily life. Due to their surface-activity, emulsifying properties, and foaming abilities, they can be applied in food, cosmetics, and pharmaceuticals. Enzymatic synthesis of glycolipids based on carbohydrates and free fatty acids or esters is often catalyzed using certain acyltransferases in reaction media of low water activity, e.g., organic solvents or notably Deep Eutectic Systems (DESs). Existing reports describing integrated processes for glycolipid production from renewables use many reaction steps, therefore this study aims at simplifying the procedure. By using microwave dielectric heating, DESs preparation was first accelerated considerably. A comparative study revealed a preparation time on average 16-fold faster than the conventional heating method in an incubator. Furthermore, lipids from robust oleaginous yeast biomass were successfully extracted up to 70% without using the pre-treatment method for cell disruption, limiting logically the energy input necessary for such process. Acidified DESs consisting of either xylitol or sorbitol and choline chloride mediated the one-pot process, allowing subsequent conversion of the lipids into mono-acylated palmitate, oleate, linoleate, and stearate sugar alcohol esters. Thus, we show strong evidence that addition of immobilized Candida antarctica Lipase B (Novozym 435®), in acidified DES mixture, enables a simplified and fast glycolipid synthesis using directly oleaginous yeast biomass. 相似文献
23.
24.
Reactions in Nitroimidazole Triggered by Low‐Energy (0–2 eV) Electrons: Methylation at N1‐H Completely Blocks Reactivity 下载免费PDF全文
Katrin Tanzer Dr. Linda Feketeová Benjamin Puschnigg Prof. Dr. Paul Scheier Prof. Dr. Eugen Illenberger Prof. Dr. Stephan Denifl 《Angewandte Chemie (International ed. in English)》2014,53(45):12240-12243
Low‐energy electrons (LEEs) at energies of less than 2 eV effectively decompose 4‐nitroimidazole (4NI) by dissociative electron attachment (DEA). The reactions include simple bond cleavages but also complex reactions involving multiple bond cleavages and formation of new molecules. Both simple and complex reactions are associated with pronounced sharp features in the anionic yields, which are interpreted as vibrational Feshbach resonances acting as effective doorways for DEA. The remarkably rich chemistry of 4NI is completely blocked in 1‐methyl‐4‐nitroimidazole (Me4NI), that is, upon methylation of 4NI at the N1 site. These remarkable results have also implications for the development of nitroimidazole based radiosensitizers in tumor radiation therapy. 相似文献
25.
At temperatures above the brittle-to-ductile transition (490 °C) in Te-doped GaAs three types of predominant defect configurations have been observed after uniaxial compression along a [001] direction: (i) twins and stacking faults (500 … 520 °C), (ii) slip zones of dislocations (≈ 550 °C) and (iii) dislocation cells (580 … 590 °C). In Part I quantitative details of the appearance of twins and stacking faults are given. Most frequently found were 30° partials in twins and stacking faults. 相似文献
26.
At temperatures above the brittle-to-ductile transition (490 °C) in Te-doped GaAs three types of predominant defect configurations have been observed after uniaxial compression along a [001] direction: (i) twins and stacking faults (500 … 520 °C), (ii) slip zones of dislocations (≈550 °C) and (iii) dislocation cells (580 … 590 °C). In Part II quantitative details of the appearance of slip and cell formation are given. Leading segments of gliding half loops are mainly of 60° type. Cell walls were formed by multiple slip of perfect dislocations. 相似文献
27.
Steffen Fischer Katrin Thümmler Katy Pfeiffer Tim Liebert Thomas Heinze 《Cellulose (London, England)》2002,9(3-4):293-300
Molten inorganic salt hydrates are highly efficient solvents forcellulose. The carboxymethylation of the polymer dissolved in this new group ofcellulose solvents was investigated. The homogeneous carboxymethylation ofcellulose in molten LiClO43H2O using sodiummonochloroacetate in the presence of NaOH is possible. The formation of CMC wasconfirmed by FT- Raman spectroscopy. Structure analysis by means of HPLC afterchain degradation showed the formation of CMC with a DS of 2 after a shortreaction time of 4 h. The derivatives exhibit a statisticaldistribution of substituents along the polymer chain if prepared in moltenLiClO43H2O as solvent. A substituent distributioninthe order C-6 > C-2 C-3 for anhydroglucose units (AGU) was concludedfrom 1H-NMR measurements. The synthesis of CMC in the swellingmediumLiClxH2O (2 x 5) yields polymers with astatistical distribution of functional groups along the chain. The watercontentof the salt melts has a dramatic influence on the DSCMC. 相似文献
28.
Synthesis and Isolation of the Titanium–Scandium Endohedral Fullerenes—Sc2TiC@Ih‐C80, Sc2TiC@D5h‐C80 and Sc2TiC2@Ih‐C80: Metal Size Tuning of the TiIV/TiIII Redox Potentials 下载免费PDF全文
Katrin Junghans Dr. Kamran B. Ghiassi Nataliya A. Samoylova Qingming Deng Marco Rosenkranz Prof. Marilyn M. Olmstead Prof. Alan L. Balch Dr. Alexey A. Popov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13098-13107
The formation of endohedral metallofullerenes (EMFs) in an electric arc is reported for the mixed‐metal Sc–Ti system utilizing methane as a reactive gas. Comparison of these results with those from the Sc/CH4 and Ti/CH4 systems as well as syntheses without methane revealed a strong mutual influence of all key components on the product distribution. Whereas a methane atmosphere alone suppresses the formation of empty cage fullerenes, the Ti/CH4 system forms mainly empty cage fullerenes. In contrast, the main fullerene products in the Sc/CH4 system are Sc4C2@C80 (the most abundant EMF from this synthesis), Sc3C2@C80, isomers of Sc2C2@C82, and the family Sc2C2 n (2 n=74, 76, 82, 86, 90, etc.), as well as Sc3CH@C80. The Sc–Ti/CH4 system produces the mixed‐metal Sc2TiC@C2 n (2 n=68, 78, 80) and Sc2TiC2@C2 n (2 n=80) clusterfullerene families. The molecular structures of the new, transition‐metal‐containing endohedral fullerenes, Sc2TiC@Ih‐C80, Sc2TiC@D5h‐C80, and Sc2TiC2@Ih‐C80, were characterized by NMR spectroscopy. The structure of Sc2TiC@Ih‐C80 was also determined by single‐crystal X‐ray diffraction, which demonstrated the presence of a short Ti=C double bond. Both Sc2TiC‐ and Sc2TiC2‐containing clusterfullerenes have Ti‐localized LUMOs. Encapsulation of the redox‐active Ti ion inside the fullerene cage enables analysis of the cluster–cage strain in the endohedral fullerenes through electrochemical measurements. 相似文献
29.
Zoltán M. Balogh Katrin Fässler Ioannis D. Platis 《Journal d'Analyse Mathématique》2011,113(1):265-291
We develop a method using the modulus of curve families to study minimisation problems for the mean distortion functional
in the class of finite distortion homeomorphisms. We apply our method to prove extremality of the spiral-stretch mappings
defined on annuli in the complex plane. This generalises results of Gutlyanskiĭ and Martio [12] and Strebel [23]. 相似文献
30.