排序方式: 共有98条查询结果,搜索用时 15 毫秒
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Jakob Wudarczyk Dr. George Papamokos Vasilis Margaritis Dr. Dieter Schollmeyer Dr. Felix Hinkel Prof. Dr. Martin Baumgarten Prof. Dr. George Floudas Prof. Dr. Klaus Müllen 《Angewandte Chemie (International ed. in English)》2016,55(9):3220-3223
Hexasubstituted benzenes have been synthesized with the highest known dipole moments, as determined by dielectric spectroscopy and DFT methods. Based on the preparation of 4,5‐diamino‐3,6‐dibromophthalonitrile, combined with a novel method to synthesize dihydrobenzimidazoles, these benzene derivatives have dipole moments in excess of 10 debye. Such dipole moments are desirable in ferroelectrics, nonlinear optics, and in organic photovoltaics. Structure determination was achieved through single‐crystal X‐ray crystallography, and the optical properties were determined by UV/Vis absorption and fluorescence spectroscopy. 相似文献
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Optical tomography of turbid media has so far been limited by systems that require fixed geometries or measurements employing fibers. We present a system that records noncontact optical measurements from diffuse media of arbitrary shapes and retrieves the three-dimensional surface information of the diffuse medium. We further present a novel method of combining this composite data set and obtain accurate fluorescence reconstructions. This approach offers significant experimental simplicity and yields high-information-content datasets. The performance of this novel tomographic approach is demonstrated with experimental reconstructions of phantoms. 相似文献
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Would near-infrared fluorescence signals propagate through large human organs for clinical studies? 总被引:5,自引:0,他引:5
We predict the capacity of near-infrared fluorescent signals to propagate through human tissue for non-invasive medical imaging. This analysis employs experimental measurements of a biologically relevant local fluorochrome embedded in tissuelike media and predicts the equivalent photon counts expected from breast, lung, brain, and muscle as a function of diameter by use of an analytical solution of the diffusion equation that can take into account large arbitrary geometries. The findings address feasibility issues for clinical studies and are relevant to recent development of near-infrared fluorescent probes and molecular beacons for in vivo applications. 相似文献
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Electrodes based on oxidized polypyrrole films have potentiometric selectivity toward anions. When the films are overoxidized, however, electron-rich groups are introduced on to the polymer chains, reversing the selectivity of the electrodes from anionic to cationic. In this study, electrochemically overoxidized polypyrrole film electrodes were prepared, and the conditions for film formation that lead to near-Nernstian potentiometric response were investigated. It was found that the doping ion, overoxidation solution, and pH affect the response of these electrodes. Redox interference is significantly lower for the overoxidized polypyrrole films than for polypyrrole electrodes. 相似文献
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Vasilis?Dimitriou Evaggelos?Kaselouris Yannis?Orphanos Makis?Bakarezos Nikolaos?Vainos Ioannis?K.?Nikolos Michael?Tatarakis Nektarios?A.?PapadogiannisEmail author 《Applied Physics A: Materials Science & Processing》2015,121(2):739-748
This article presents experimental results supported by advanced three-dimensional modeling for the dynamics emerging from the interaction of nanosecond laser pulses with thin metal films on dielectric substrates, especially at the melting and ablation regimes. Matter dynamics, such as the generation and propagation of surface acoustic waves and permanent deformations, are imaged with the use of a very high spatial and temporal resolution interferometric method accompanied by white-light interferometry. A three-dimensional finite element model is developed aiming to fully describe the spatiotemporal dynamics and predict with high accuracy the thermo-mechanical phenomena around melting and ablation regimes where phase changes take place. The ability of very high spatial and temporal resolution, the whole-field three-dimensional imaging as well as the simultaneous study of the laser pulse–thin film interaction regimes, makes this study valuable for applications where detailed knowledge of the thermo-mechanical behavior of matter under pulsed laser excitation is critical. 相似文献
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Dr. Vasilis Tseliou Don Schilder Dr. Marcelo F. Masman Dr. Tanja Knaus Prof. Dr. Francesco G. Mutti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(10):3315-3325
The l -lysine-ϵ-dehydrogenase (LysEDH) from Geobacillus stearothermophilus naturally catalyzes the oxidative deamination of the ϵ-amino group of l -lysine. We previously engineered this enzyme to create amine dehydrogenase (AmDH) variants that possess a new hydrophobic cavity in their active site such that aromatic ketones can bind and be converted into α-chiral amines with excellent enantioselectivity. We also recently observed that LysEDH was capable of reducing aromatic aldehydes into primary alcohols. Herein, we harnessed the promiscuous alcohol dehydrogenase (ADH) activity of LysEDH to create new variants that exhibited enhanced catalytic activity for the reduction of substituted benzaldehydes and arylaliphatic aldehydes to primary alcohols. Notably, these novel engineered dehydrogenases also catalyzed the reductive amination of a variety of aldehydes and ketones with excellent enantioselectivity, thus exhibiting a dual AmDH/ADH activity. We envisioned that the catalytic bi-functionality of these enzymes could be applied for the direct conversion of alcohols into amines. As a proof-of-principle, we performed an unprecedented one-pot “hydrogen-borrowing” cascade to convert benzyl alcohol to benzylamine using a single enzyme. Conducting the same biocatalytic cascade in the presence of cofactor recycling enzymes (i.e., NADH-oxidase and formate dehydrogenase) increased the reaction yields. In summary, this work provides the first examples of enzymes showing “alcohol aminase” activity. 相似文献
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N Lozano WT Al-Jamal A Taruttis N Beziere NC Burton J Van den Bossche M Mazza E Herzog V Ntziachristos K Kostarelos 《Journal of the American Chemical Society》2012,134(32):13256-13258
The design of liposome-nanoparticle hybrids offers a rich toolbox for the fabrication of multifunctional modalities. A self-assembled liposome-gold nanorod hybrid vesicular system that consists of lipid-bilayer-associated gold nanorods designed to allow deep tissue detection, therapy, and monitoring in living animals using multispectral optoacoustic tomography has been fabricated and characterized in vitro and in vivo. 相似文献
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