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排序方式: 共有253条查询结果,搜索用时 15 毫秒
41.
This paper reports a new patterning method, which utilizes NaOH to facilitate the irreversible binding between the PDMS stamp and substrates and subsequent cohesive mechanical failure to transfer the PDMS patterns. Our method shows high substrate tolerance and can be used to "print" various PDMS geometries on a wide range of surfaces, including Si100, glass, gold, polymers, and patterned SU8 photoresist. Using this technique, we are able to locally change the wettability of substrate surfaces by printing well-defined PDMS architectures on the patterned SU8 photoresist. It is possible to generate differential wetting and dewetting properties in microchannels and in the PDMS printed area, respectively. 相似文献
42.
Microcantilever bending can be reversibly driven by conformational changes of phosphate containing polyelectrolyte brushes when exposed to different pH or salt solutions. The deflection of the cantilevers allows a detailed analysis of the properties of polymer brushes, while these systems are also a first step toward polymer-based nanoactuators. 相似文献
43.
Zhou F Zheng Z Yu B Liu W Huck WT 《Journal of the American Chemical Society》2006,128(50):16253-16258
This article describes a general synthetic route to laterally distinctive multicomponent polymer brushes on gold. The procedure involves repeated surface patterning using microcontact printing (muCP) of initiator-terminated thiols without backfilling with inert thiols and surface-initiated atomic transfer radical polymerization steps. In between brush growth, the remaining initiator moieties are deactivated to avoid reinitiation on existing brushes. Optical and fluorescence microscopy, atomic force microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy have been used to characterize every step of this procedure. We found that brushes can be grown from initiator-modified surfaces that contain bare gold areas and that these areas remain available for further patterning using muCP. To demonstrate the flexibility of this approach, surfaces containing four different polymer brushes in patterns ranging from 2 x 4 microm lines to 20 x 20 microm squares were fabricated. The range of chemical functionalities incorporated includes cationic and anionic polyelectrolytes, as well as thermally responsive polymers. 相似文献
44.
Daniel J. Williams Daniel Gulla Kimberly A. Arrowood Lindsey M. Bloodworth Angela L. Carmack Taylor J. Evers Mark S. Wilson Javier J. Concepcion Carol A. S. Brevett Benjamin E. Huck Donald VanDerveer 《Journal of chemical crystallography》2009,39(8):581-584
Abstract A new compound, [Cd(mipit)4][PF6]2 has been synthesized and characterized via standard solid and solution state methods including single crystal X-ray crystallography
(mipit = 1-methyl-3-(2-propyl)-2(3H)-imidazolethione). The title compound crystallizes in tetragonal space group I4
1
/a with a = 12.478(2) ?, b = 12.478(2) ?, c = 28.806(6) ?, and Z = 4. The complex is a high melting, colorless solid that has a distorted tetrahedral CdS4 coordination geometry. Thermogravimetric analysis results for the title compound as well as for another potential CdS synthon
and two potential CdSe synthons are reported.
Graphical Abstract The synthesis and characterization of the title compound, a new ionic homoleptic cadmium complex, tetrakis[1-methyl-3-(2-propyl)-2(3H)-imidazolethione]cadmium(II)
hexafluorophosphate is reported. The results of a single crystal X-ray diffraction analysis reveal a distorted tetrahedral
CdS4 coordination sphere about the cadmium.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
45.
Theberge AB Mayot E El Harrak A Kleinschmidt F Huck WT Griffiths AD 《Lab on a chip》2012,12(7):1320-1326
This paper presents a droplet-based microfluidic platform for miniaturized combinatorial synthesis. As a proof of concept, a library of small molecules for early stage drug screening was produced. We present an efficient strategy for producing a 7 × 3 library of potential thrombin inhibitors that can be utilized for other combinatorial synthesis applications. Picolitre droplets containing the first type of reagent (reagents A(1), A(2), …, A(m)) were formed individually in identical microfluidic chips and then stored off chip with the aid of stabilizing surfactants. These droplets were then mixed to form a library of droplets containing reagents A(1-m), each individually compartmentalized, which was reinjected into a second microfluidic chip and combinatorially fused with picolitre droplets containing the second reagent (reagents B(1), B(2), …, B(n)) that were formed on chip. The concept was demonstrated with a three-component Ugi-type reaction involving an amine (reagents A(1-3)), an aldehyde (reagents B(1-7)), and an isocyanide (held constant), to synthesize a library of small molecules with potential thrombin inhibitory activity. Our technique produced 10(6) droplets of each reaction at a rate of 2.3 kHz. Each droplet had a reaction volume of 3.1 pL, at least six orders of magnitude lower than conventional techniques. The droplets can then be divided into aliquots for different downstream screening applications. In addition to medicinal chemistry applications, this combinatorial droplet-based approach holds great potential for other applications that involve sampling large areas of chemical parameter space with minimal reagent consumption; such an approach could be beneficial when optimizing reaction conditions or performing combinatorial reactions aimed at producing novel materials. 相似文献
46.
Pallua JD Recheis W Pöder R Pfaller K Pezzei C Hahn H Huck-Pezzei V Bittner LK Schaefer G Steiner E Andre G Hutwimmer S Felber S Pallua AK Pallua AF Bonn GK Huck CW 《The Analyst》2012,137(7):1584-1595
In this study the potential of new imaging techniques such as Magnetic Resonance Imaging (MRI), Matrix-Assisted Laser Desorption/Ionization (MALDI) profiling mass spectrometry ("MALDI Profiling") and Fourier Transform Infrared (FTIR) spectroscopic imaging was evaluated to study morphological and molecular patterns of the potential medicinal fungus Hericium coralloides. For interpretation, the MALDI profiling, FTIR imaging and MRI results were correlated with histological information gained from Scanning Electron Microscopy (SEM) and Light Microscopy (LM). Additionally we tested several evaluation processes and optimized the methodology for use of complex FTIR images to monitor molecular patterns. It is demonstrated that the combination of these spectroscopic methods enables to gain a more distinct picture concerning morphology and distribution of active ingredients. We were able to obtain high quality FTIR imaging and MALDI-profiling results and to distinguish different tissue types with their chemical ingredients. Beside this, we have created a 3-D reconstruction of a mature Hericium basidioma, based on the MRI dataset: analyses allowed, for the first time, a realistic approximation of the "evolutionary effectiveness" of this bizarrely formed basidioma type, concerning the investment of sterile tissue and its reproductive output (production of basidiospores). 相似文献
47.
Dr. Oliver R. Maguire Dr. Albert S. Y. Wong Mathieu G. Baltussen Peer van Duppen Aleksandr A. Pogodaev Prof. Dr. Wilhelm T. S. Huck 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(7):1676-1682
Current efforts to design functional molecular systems have overlooked the importance of coupling out-of-equilibrium behaviour with changes in the environment. Here, the authors use an oscillating reaction network and demonstrate that the application of environmental forcing, in the form of periodic changes in temperature and in the inflow of the concentration of one of the network components, removes the dependency of the periodicity of this network on temperature or flow rates and enforces a stable periodicity across a wide range of conditions. Coupling a system to a dynamic environment can thus be used as a simple tool to regulate the output of a network. In addition, the authors show that coupling can also induce an increase in behavioural complexity to include quasi-periodic oscillations. 相似文献
48.
Danny Q. Thach Zachary G. Brill Huck K. Grover Kenneth V. Esguerra Jordan K. Thompson Thomas J. Maimone 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1548-1552
The ophiobolin sesterterpenes are notable plant pathogens which have recently elicited significant chemical and biological attention because of their intriguing carbogenic frameworks, reactive functionalities, and emerging anticancer profiles. Reported herein is a total synthesis of (+)-6-epi-ophiobolin A in 14 steps, a task which addresses construction of the synthetically challenging spirocyclic tetrahydrofuran motif as well as several other key stereochemical problems. This work demonstrates a streamlined synthetic platform to complex ophiobolins leveraging disparate termination modes of a radical polycyclization cascade for divergent elaboration and functionalization. 相似文献
49.
T. Björnstad M.J.G. Borge P. Dessagne R.-D. Von Dincklage G.T. Ewan P.G. Hansen A. Huck B. Jonson G. Klotz A. Knipper P.O. Larsson G. Nyman H.L. Ravn C. Richard-Serre K. Riisager D. Schardt G. Walter 《Nuclear Physics A》1985,443(2):283-301
Delayed proton and gamma emissions following the β-decay of 32Ar have been studied. The half-life of 32Ar is 98 ± 2 ms, and the T = 2 analogue state in 32Cl lies at the excitation energy 5036 ± 12 keV. From the intensity of the feeding to this state the proton intensities can be converted to an absolute scale leading to a total proton branching ratio of (43 ± 3)%. From proton-gamma coincidence measurements it emerges that (1.9 ± 0.2)% of the protons lead to the first-excited state in 31S. A level scheme up to 8.75 MeV excitation in 32Cl has been constructed and the Gamow-Teller strength function has been deduced. The result is a renormalization of the axial-vector strength to (49 ± 5)% of the free-nucleon value. 相似文献
50.
J. P. Dufour S. Beraud-Sudreau R. Del Moral H. Emmermann A. Fleury F. Hubert C. Poinot M. Pravikoff J. Frehaut M. Beau A. Bertin G. Giraudet A. Huck G. Klotz C. Miehe C. Richard-Serre H. Delagrange 《Zeitschrift für Physik A Hadrons and Nuclei》1984,319(2):237-238
The new beta-delayed neutron emitter15B has been observed. The measured half-life is 11 ms ±1 ms and limits have been set on other decay channels: P0n<5%, P2n<1.5%. The beta emitter12Be has been separated, unambiguously identified, and its half-life has been measured to be 24±1 ms. 相似文献