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991.
The attachment of immortalized hypothalamic murine neurons onto the surface of an acoustic wave device yields both positive series resonant frequency (f(s)) and motional resistance (R(m)) shifts as opposed to commonly reported negative f(s) and positive R(m) shifts observed for other cell types. These unique shifts have been confirmed by a variety of experiments in order to verify the source and the validity of the signals. These studies involved monitoring responses to solution flow, the absence of serum proteins, the effect of reducing specific cell -surface interactions and the disruption of the neuronal cytoskeleton components. For the adhesion and deposition of neurons, f(s) and R(m) shifts are positively correlated to the amount of adhered neurons on the sensor surface, whereas non-adhered neurons do not produce any significant change in the monitored parameters. In the absence of serum proteins, initial cell adhesion is followed by subsequent cell death and removal from the sensor surface. The presence of the peptide, GRGDS is observed to significantly reduce cell-surface specific interactions compared to the control of SDGRG and this produces f(s) and R(m) responses that are opposite in direction to that observable for cell adhesion. Cytoskeletal studies, using the drugs nocodazole (10 μM), colchicine (1 μM), cytochalasin B (10 μM) and cytochalasin D (2 μM) all elicit neuronal responses that are validated by phalloidin actin-filament staining. These results indicate that the responses are associated with a wide range of cellular changes that can be monitored and studied using the acoustic wave method in real time, under optimal physiological conditions. 相似文献
992.
Alkylidene malonates undergo efficient conjugate allylation upon treatment with allylstannanes or allylsilanes under the action of ytterbium catalysis. 相似文献
993.
ZHAO JianWen QIAN Jun SHEN YongQiang WANG XiaoHua SHI AiHua & LEE ChunWei College of Chemistry Chemical Engineering Jishou University Jishou China Printable Electronics Research Centre Suzhou Institute of Nanotech Nano-bionics Chinese Academy of Sciences Suzhou China Key Laboratory of Photochemical Conversion Optoelectronic Materials TIPC Beijing China School of Materials Science Engineering Nanyang Technological University Si... 《中国科学B辑(英文版)》2011,(9)
Here we report a simple and scalable method to fabricate high performance thin-film field-effect transistors(FETs) with high yield based on chemically functionalized single-walled carbon nanotubes(SWNTs) by organic radical initiators.The UV-Vis-NIR spectra,Raman spectra and electrical characterization demonstrated that metallic species in CoMoCat 65 and HiPco SWNTs could be effectively eliminated after reaction with some organic radical initiators.The effects of the substrate properties on the electrical pr... 相似文献
994.
Effects of pressure, temperature, and pH on the sonochemical destruction of 1,1,1-trichloroethane in dilute aqueous solution 总被引:2,自引:0,他引:2
There is an increasing interest in the application of high intensity ultrasound as an advanced oxidation technique. In this study, 1,1,1-trichloroethane (TCA) is the compound being subjected to ultrasonic irradiation. The study focuses on the effects of pressure (0.103-0.241 MPa), temperature (6-19.4 degrees C) and pH (3.96-12.5). Optimum conditions of treatment are discerned from the results of the experiments based on a center composite design. The results show that about 98% of TCA can be removed in 1 h of treatment (starting concentrations average 80 mg/l). Also, experiments indicate that the initial concentration does not affect destruction rate in this system. Optimum conditions as indicated by statistical analysis are at T = 14.2 degrees C, P = 0.212 MPa and pH = 10.9. This study also presents a method to normalize rate constants for changes in the power-to-volume ratio. 相似文献
995.
A copper(II)-catalyzed oxidative cyclization of enamides to oxazoles via vinylic C-H bond functionalization at room temperature is described. Various 2,5-disubstituted oxazoles bearing aryl, vinyl, alkyl, and heteroaryl substituents could be synthesized in moderate to high yields. This reaction protocol is complementary to our previously reported iodine-mediated cyclization of enamides to afford 2,4,5-trisubstituted oxazoles. 相似文献
996.
Kleeberg C Crawford AG Batsanov AS Hodgkinson P Apperley DC Cheung MS Lin Z Marder TB 《The Journal of organic chemistry》2012,77(1):785-789
The Lewis base adduct of B(2)pin(2) and the NHC (1,3-bis(cyclohexyl)imidazol-2-ylidene), which was proposed to act as a source of nucleophilic boryl groups in the β-borylation of α,β-unsaturated ketones, has been isolated, and its solid state structure and solution behavior was studied. In solution, the binding is weak, and NMR spectroscopy reveals a rapid exchange of the NHC between the two boron centers. DFT calculations reveal that the exchange involves dissociation and reassociation of NHC rather than an intramolecular process. 相似文献
997.
The family of block spaces with variable exponents is introduced. We obtain some fundamental properties of the family of block spaces with variable exponents. They are Banach lattices and they are generalizations of the Lebesgue spaces with variable exponents. Moreover, the block space with variable exponents is a pre-dual of the corresponding Morrey space with variable exponents. The main result of this paper is on the boundedness of the Hardy-Littlewood maximal operator on the block space with variable exponents. We find that the Hardy-Littlewood maximal operator is bounded on the block space with variable exponents whenever the Hardy-Littlewood maximal operator is bounded on the corresponding Lebesgue space with variable exponents. 相似文献
998.
TIMO A LÄHDE EVGENY EPELBAUM HERMANN KREBS DEAN LEE ULF-G MEISSNER GAUTAM RUPAK 《Pramana》2014,83(5):651-659
We review the calculation of the Hoyle state of 12C in nuclear lattice effective field theory (NLEFT) and its anthropic implications in the nucleosynthesis of 12C and 16O in red giant stars. We also analyse the extension of NLEFT to the regime of medium-mass nuclei, with emphasis on the determination of the ground-state energies of the α nuclei 16O, 20Ne, 24Mg, and 28Si by Euclidean time projection. Finally, we discuss recent NLEFT results for the spectrum, electromagnetic properties, and α-cluster structure of 16O. 相似文献
999.
Most of the theoretical studies of the growth of cells/dendrites in the literature are based on the assumption that it is a steady-state phenomenon. The analysis of cells/dendritic structures in the unsteady-state regime is very important, since it encompasses the majority of industrial solidification processes. The aim of the present investigation was to validate the predictions furnished by the cellular and primary dendritic growth models in the literature for unsteady-state conditions against a large spectrum of experimental data, which includes those for a variety of Al alloys (Al–Cu, Al–Si, Al–Fe, Al–Bi, Al–Ni, Al–Sn) and low thermal diffusivity alloys, such as Sn–Pb and Pb–Sb. The predictions furnished by the Hunt–Lu model do not match the cellular experimental scatter for any examined alloy system. However, this model matches well with the primary dendritic growth of Al alloys, with the exception of Al–Sn alloys, for which the Hunt–Thomas approach has to be applied. The primary dendritic predictions of Bouchard–Kirkaldy's model, performed with the originally suggested a 1 calibration factors are, in most cases, located above the experimental points. Experimental growth laws relating cellular and dendritic spacings with the tip growth rate and the cooling rate, respectively, are established. 相似文献
1000.
I-Tsan Liu Min-Hsiung Hon Chi-Yun Kuan Lay-Gaik Teoh 《Applied Physics A: Materials Science & Processing》2013,111(4):1181-1186
Silver/ceria (Ag/CeO2) nanocomposites were prepared from Ce(NO3)3?6H2O, AgNO3, and NH4OH with different molar ratios through a hydrothermal process, and then were completed by carrying out the precursors calcining at 750 °C for 2 h under air atmosphere. Below 1 % of Ag concentration in Ag/CeO2 nanocomposites, the Ag crystalline structure does not appear. XRD and TEM results show evidence of two different effects (the agglomeration and the barrier effects) governing the process of crystal growth. HR-TEM image and EDX elemental analysis of the Ag/CeO2 nanocomposite confirmed that isolated Ag nanocrystals are dispersed in the CeO2 matrix. The red shifts are attributed to the quantum confinement effect and the valence change of the Ce+ ions. Ag nanoparticles can help to improve the absorption of visible light, enhancing the absorption intensity of Ag/CeO2 nanocomposite. These results are of great significance for the control of microstructure, crystallinity, and applications for the development of nanocomposite materials. 相似文献