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901.
Mahabub A. Bhuiyan Zakhar R. Kudrynskyi Debarati Mazumder Jake D. G. Greener Oleg Makarovsky Christopher J. Mellor Evgeny E. Vdovin Benjamin A. Piot Inna I. Lobanova Zakhar D. Kovalyuk Marina Nazarova Artem Mishchenko Kostya S. Novoselov Yang Cao Laurence Eaves Go Yusa Amalia Patan 《Advanced functional materials》2019,29(3)
The transfer of electronic charge across the interface of two van der Waals crystals can underpin the operation of a new class of functional devices. Among van der Waals semiconductors, an exciting and rapidly growing development involves the “post‐transition” metal chalcogenide InSe. Here, field effect phototransistors are reported where single layer graphene is capped with n‐type InSe. These device structures combine the photosensitivity of InSe with the unique electrical properties of graphene. It is shown that the light‐induced transfer of charge between InSe and graphene offers an effective method to increase or decrease the carrier density in graphene, causing a change in its resistance that is gate‐controllable and only weakly dependent on temperature. The charge transfer at the InSe/graphene interface is probed by Hall effect and photoconductivity measurmentes and it is demonstrated that light can induce a sign reversal of the quantum Hall voltage and photovoltaic effects in the graphene layer. These findings demonstrate the potential of light‐induced charge transfer in gate‐tunable InSe/graphene phototransistors for optoelectronics and quantum metrology. 相似文献
902.
Jasper J. Michels Suzanne H.P.M. de Winter Laurence H.G. Symonds 《Organic Electronics》2009,10(8):1495-1504
We demonstrate that artificial neural network modeling is a viable tool to predict the processing dependence of gravure printed light-emitting polymer layers for flexible OLED lighting applications. The (local) thickness of gravure printed light-emitting polymer (LEP) layers was analyzed using microdensitometry, after which the data was used to train a multi-layer neural network using error back propagation. Cell engraving depth, printing speed, and polymer concentration were used as input parameters of the neural network. Mean printed layer thickness, relative RMS roughness and feature anisotropy were defined as output parameters. The inhomogeneity of the gravure printed LEP layers was defined by two parameters, being the normalized standard deviation from the mean layer thickness, as well as the anisotropy or ‘directionality’ of the roughness features. Despite the limited number of input parameters, a fair prediction accuracy was obtained once new input data was fed into the trained network. The prediction error for the three output parameters was of the order: anisotropy > roughness > mean layer thickness. Calculating the magnitude of the output parameters as a function of the total space determined by the input parameters can be used as a way to find optimal printing conditions. These ‘landscape’ plots also reveal qualitative information on the rheological behavior of the inks during the printing process. 相似文献
903.
A Fluorinated Bola‐Amphiphilic Dendrimer for On‐Demand Delivery of siRNA,via Specific Response to Reactive Oxygen Species 下载免费PDF全文
Yang Wang Chao Chen Aura Tintaru Yu Cao Juan Liu Fabio Ziarelli Jingjie Tang Hongbo Guo Roseline Rosas Suzanne Giorgio Laurence Charles Palma Rocchi Ling Peng 《Advanced functional materials》2016,26(47):8594-8603
Functional materials capable of responding to stimuli intrinsic to diseases are extremely important for specific drug delivery at the disease site. However, developing on‐demand stimulus‐responsive vectors for targeted delivery is highly challenging. Here, a stimulus‐responsive fluorinated bola‐amphiphilic dendrimer is reported for on‐demand delivery of small interfering RNA (siRNA) in response to the characteristic high level of reactive oxygen species (ROS) in cancer cells. This dendrimer bears a ROS‐sensitive thioacetal in the hydrophobic core and positively charged poly(amidoamine) dendrons at the terminals, capable of interacting and compacting the negatively charged siRNA into nanoparticles to protect the siRNA and promote cellular uptake. The ROS‐sensitive feature of this dendrimer boosts specific and efficient disassembly of the siRNA/vector complexes in ROS‐rich cancer cells for effective siRNA delivery and gene silencing. Moreover, the fluorine tags in the vector enable 19F‐NMR analysis of the ROS‐responsive delivery process. In addition, this ingenious and distinct bola‐amphiphilic dendrimer is also able to combine the advantageous delivery features of both lipid and dendrimer vectors. Therefore, it represents an innovative on‐demand stimulus‐responsive delivery platform. 相似文献
904.
Andrea Weiss Laurence Williams J. MacGregor Smith 《Journal of Mathematical Modelling and Algorithms》2012,11(4):361-386
Evacuation networks from buildings represent a complex architectural and engineering phenomenon. The problem is fundamentally a transient stochastic process embedded on a three-dimensional graph network topology. Not only is the analysis of the problem challenging, but synthesizing the way occupants should exit the facility is also problematic. This paper addresses the two key concerns in the evacuation problem: performance analysis and their optimization. Two facilities on the University of Massachusetts campus provide the backdrop and case studies for this paper. Extensive computational results support the theoretical decomposition approach to the problems. 相似文献
905.
Rekha P. Kulkarni Laurence Grammont 《Numerical Functional Analysis & Optimization》2013,34(11-12):1339-1359
In [14], a new method based on projections onto a space of piecewise polynomials of degree ≤r ? 1 has been shown to give a convergence of order 4r for second-kind integral equations. The size of the system of equations that must be solved, in implementing this method, remains the same as for the Galerkin/collocation method. In this article the solution obtained by the proposed method is shown to have an asymptotic series expansion which remains valid in the discrete version. The Richardson extrapolation can then be used to further improve the order of convergence to 4r + 2. 相似文献
906.
Malaud E Piquer D Merle D Molina L Guerrier L Boschetti E Saussine M Marty-Ané C Albat B Fareh J 《Electrophoresis》2012,33(3):470-482
Atherosclerosis is one of the most important causes of cardiovascular and cerebrovascular events. Although phenotypic differentiation between stable and unstable plaques is currently possible, proteomic analysis of the atherosclerotic plaque could offer a global view of the atherosclerosis pathology. With the objective to highlight the detection of low-abundance proteins, we reduced the dynamic range of proteins by combinatorial peptide ligand library treatment of human carotid artery atherosclerotic plaques. After enrichment step, abundance of major proteins was decreased, revealing different protein profiles as assessed by both SDS-polyacrylamide gel electrophoresis and two-dimensional electrophoresis comparative analyses. Identification of proteins that were contained in a spot allowed finding large differences between noncomplicated and complicated plaques from carotid atherosclerotic lesions. Novel low-abundance proteins were detected correlating very well with biological alterations related to atherosclerosis (heat shock protein 27 (HSP27) isoforms, aldehyde dehydrogenase, moesin, Protein kinase C delta-binding protein, and inter-α trypsin inhibitor family heavy chain-related protein (ITIH4)). At the same time, the differential expression of known proteins of interest such as hemoglobin β-chain and heat shock protein 27 between noncomplicated and hemorrhagic complicated plaques was maintained after enrichment step. The detection of different isoforms of a low-abundance protein such as heat shock protein 27 species was actually improved after enrichment of tissue protein extracts. All of these findings clearly support further investigations in view to confirm the role of these proteins as possible biomarkers. 相似文献
907.
Felippe LG Batista JM Baldoqui DC Nascimento IR Kato MJ He Y Nafie LA Furlan M 《Organic & biomolecular chemistry》2012,10(21):4208-4214
The absolute configuration and solution-state conformers of three peperomin-type secolignans isolated from Peperomia blanda (Piperaceae) are unambiguously determined by using vibrational circular dichroism (VCD) spectroscopy associated with density functional theory (DFT) calculations. Advantages of VCD over the electronic form of CD for the analysis of diastereomers are also discussed. This work extends our growing knowledge about secondary metabolites within the Piperaceae family species while providing a definitive and straightforward method to assess the absolute stereochemistry of secolignans. 相似文献
908.
Kurouski D Dukor RK Lu X Nafie LA Lednev IK 《Chemical communications (Cambridge, England)》2012,48(23):2837-2839
Amyloid fibrils are associated with many neurodegenerative diseases and are considered to be the energetically most favorable form of proteins. Here we report that a small pH change initiates spontaneous transformation of insulin fibrils from one polymorph to another. As a result, fibril supramolecular chirality overturns both accompanying morphological and structural changes. 相似文献
909.
Evans HL Slade RL Carroll L Smith G Nguyen QD Iddon L Kamaly N Stöckmann H Leeper FJ Aboagye EO Spivey AC 《Chemical communications (Cambridge, England)》2012,48(7):991-993
The copper-free click (CFC) reaction has been evaluated for its potential application to in vivo pre-targeting for PET imaging. A promising biodistribution profile is demonstrated when employing [(18)F]2-fluoroethylazide ([(18)F]1) and optimisation of the CFC reaction with a series of cyclooctynes shows that reactions proceed efficiently with tantalizing opportunities for application-specific tuning. 相似文献
910.
The dynamics of A + B → C reaction fronts is studied under modulated gravitational acceleration by means of a combination of parabolic flight experiments and numerical simulations. During modulated gravity the front position undergoes periodic modulation with an accelerated front propagation under hyper-gravity together with a slowing down under low gravity. The underlying reason for this is an amplification and a decay, respectively, of the buoyancy-driven double vortex associated with the front propagation under standard gravitational acceleration, as explained by reaction-diffusion-convection simulations of convection around an A + B → C front. Deeper insights into the correlation between grey-value changes in the experimental shadowgraph images and characteristic changes in the concentration profiles are obtained by a numerical simulation of the imaging process. 相似文献