共查询到20条相似文献,搜索用时 9 毫秒
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Murugesan Velayutham Martin Poncelet Timothy D. Eubank Benoit Driesschaert Valery V. Khramtsov 《Molecules (Basel, Switzerland)》2021,26(9)
Alterations in viscosity of biological fluids and tissues play an important role in health and diseases. It has been demonstrated that the electron paramagnetic resonance (EPR) spectrum of a 13C-labeled trityl spin probe (13C-dFT) is highly sensitive to the local viscosity of its microenvironment. In the present study, we demonstrate that X-band (9.5 GHz) EPR viscometry using 13C-dFT provides a simple tool to accurately measure the microviscosity of human blood in microliter volumes obtained from healthy volunteers. An application of low-field L-band (1.2 GHz) EPR with a penetration depth of 1–2 cm allowed for microviscosity measurements using 13C-dFT in the living tissues from isolated organs and in vivo in anesthetized mice. In summary, this study demonstrates that EPR viscometry using a 13C-dFT probe can be used to noninvasively and rapidly measure the microviscosity of blood and interstitial fluids in living tissues and potentially to evaluate this biophysical marker of microenvironment under various physiological and pathological conditions in preclinical and clinical settings. 相似文献
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Jens Pettelkau Christian H. Ihling Petra Frohberg Lars van Werven Olaf Jahn Andrea Sinz 《Journal of the American Society for Mass Spectrometry》2014,25(9):1628-1641
We describe the use of the 13C-labeled artificial amino acid p-benzoyl-L-phenylalanine (Bpa) to improve the reliability of cross-linked product identification. Our strategy is exemplified for two protein–peptide complexes. These studies indicate that in many cases the identification of a cross-link without additional stable isotope labeling would result in an ambiguous assignment of cross-linked products. The use of a 13C-labeled photoreactive amino acid is considered to be preferred over the use of deuterated cross-linkers as retention time shifts in reversed phase chromatography can be ruled out. The observation of characteristic fragment ions additionally increases the reliability of cross-linked product assignment. Bpa possesses a broad reactivity towards different amino acids and the derived distance information allows mapping of spatially close amino acids and thus provides more solid structural information of proteins and protein complexes compared to the longer deuterated amine-reactive cross-linkers, which are commonly used for protein 3D-structure analysis and protein–protein interaction studies. Figure
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Kilian Muñiz Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(50):9412-9423
Recent years have seen the rapid development of a new field of palladium catalysis in organic synthesis. This chemistry takes place outside the usually encountered Pd0/PdII cycles. It is characterized by the presence of strong oxidants, which prevent further palladium(II)‐promoted reactions at a given point of the catalytic cycle by selective metal oxidation. The resulting higher‐oxidation‐state palladium complexes have been used to develop a series of new synthetic transformations that cannnot be realized within conventional palladium catalysis. This type of catalysis by palladium in a higher oxidation state is of significant synthetic potential. 相似文献
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Dr. Eric D. Slack Dr. Raina Seupel Prof. Dr. Donald H. Aue Prof. Dr. Gerhard Bringmann Prof. Dr. Bruce H. Lipshutz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14237-14245
A stereoselective total synthesis of O,N-dimethylhamatine, an analogue of an axially chiral naphthylisoquinoline natural biaryl product from tropical Ancistrocladus lianas, is reported. The route features a late-stage atropo-diastereoselective biaryl bond formation. Generation of this especially challenging, sterically hindered tetra-ortho-substituted array was achieved by using Nolan's (IPr*NHC)PdCinCl pre-catalyst under mild Negishi coupling conditions. Discussion is offered regarding the selectivity obtained experimentally and predicted from DFT calculations on the key biaryl coupling step that leads to the desired M-diastereomer. 相似文献
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Dr. Qing‐Yuan Yang Prof. Dr. Jean‐Marie Lehn 《Angewandte Chemie (International ed. in English)》2014,53(18):4572-4577
White‐light‐emitting materials and devices have attracted enormous interest because of their great potential for various lighting applications. We herein describe the light‐emitting properties of a series of new difunctional organic molecules of remarkably simple structure consisting of two terminal 4‐pyridone push–pull subunits separated by a polymethylene chain. They were found to emit almost “pure” white light as a single organic compound in the solid state, as well as when incorporated in a polymer film. To the best of our knowledge, they are the simplest white‐light‐emitting organic molecules reported to date. 相似文献
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Yonglei Que Hao Shao Haibing He Shuanhu Gao 《Angewandte Chemie (International ed. in English)》2020,59(19):7444-7449
The asymmetric total synthesis of farnesin, a rearranged ent‐kaurenoid, was achieved through a convergent approach involving photo‐Nazarov and intramolecular aldol cyclizations to build the syn‐syn‐syn hydrofluorenol ABC ring system and bicyclo[3.2.1]octane CD ring system in the first application of a UV‐light‐induced excited‐state Nazarov cyclization of a non‐aromatic dicyclic divinyl ketone in a total synthesis. Unlike the conventional acid‐promoted ground‐state Nazarov reaction, the excited‐state Nazarov reaction enables stereospecific formation of the highly strained syn‐syn‐syn‐fused hydrofluorenone scaffold through a disrotatory cyclization. 相似文献
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A novel energetic microporous metal‐organic coordination polymer {[Ni(tnbpdc)(bpy)(H2O)2] · 1.5(DMF)}n ( 1 ) (tnbpdc = 2, 2′,6, 6′‐tetranitro‐4, 4′‐biphenyl dicarboxylate, bpy = 4, 4′‐bipyridine) was prepared solvothermally and characterized by elemental, IR spectroscopic, and single‐crystal X‐ray diffraction analyses. The X‐ray crystal structure of 1 revealed a rectangular‐shaped grid constructed with tnbpdc linkers and bpy linkers, with the free tunnel size estimated as 11 × 15 Å2. The thermal stability of the compound was evaluated by differential scanning calorimetry and thermogravimetric analysis. Such complexes may find application as novel heat‐resistant energetic materials. 相似文献