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71.
72.
In a confined two dimensional system of non-interacting electrons in a normal constant magnetic field, the current is calculated along the sample as a response to an electric field in the same direction which is switched on and then off. The resulting stationary current is shown to be a step-like function of the electron density. 相似文献
73.
Kamphuis MM Johnston AP Such GK Dam HH Evans RA Scott AM Nice EC Heath JK Caruso F 《Journal of the American Chemical Society》2010,132(45):15881-15883
Targeted delivery of drugs to specific cells allows a high therapeutic dose to be delivered to the target site with minimal harmful side effects. Combining targeting molecules with nanoengineered drug carriers, such as polymer capsules, micelles and polymersomes, has significant potential to improve the therapeutic delivery and index of a range of drugs. We present a general approach for functionalization of low-fouling, nanoengineered polymer capsules with antibodies using click chemistry. We demonstrate that antibody (Ab)-functionalized capsules specifically bind to colorectal cancer cells even when the target cells constitute less than 0.1% of the total cell population. This precise targeting offers promise for drug delivery applications. 相似文献
74.
75.
Dung T. Tran Ian P. Jones Jon A. Preece Roy L. Johnston Coenraad R. van den Brom 《Journal of nanoparticle research》2011,13(9):4229-4237
Dodecanethiol-capped Cu–Au nanoparticles, synthesized via a successive two-phase (water/toluene) and galvanic-exchange procedure,
were characterized using transmission electron microscopy (TEM). The size range of the particles is around 1–7 nm. Electron-induced
morphological evolution was observed under high resolution (HR) TEM. Cuboctahedral morphology was found to be thermodynamically
stable. Electron-induced aggregation of two particles was also observed. Chemical ordering of cuboctahedral particles was
studied by atomic-resolution high angle annular dark field (HAADF) imaging in scanning TEM (STEM) mode and energy dispersive
X-ray (EDX) element mapping using a silicon drift detector (SDD). The particles were found to be Cu–Au mixed, and to be stable
in air. Surface plasmon resonance (SPR), which is dependent on local structure and morphology, was investigated by electron
energy loss spectroscopy (EELS). 相似文献
76.
77.
F R Johnston J E Boyland M Meadows E Shale 《The Journal of the Operational Research Society》1999,50(12):1267-1271
Simple (equally weighted) moving averages are frequently used to estimate the current level of a time series, with this value being projected as a forecast for future observations. A key measure of the effectiveness of the method is the sampling error of the estimator, which this paper defines in terms of characteristics of the data. This enables the optimal length of the average for any steady state model to be established and the lead time forecast error derived. A comparison of the performance of a simple moving average (SMA) with an exponentially weighted moving average (EWMA) is made. It is shown that, for a steady state model, the variance of the forecast error is typically less than 3% higher than the appropriate EWMA. This relatively small difference may explain the inconclusive results from the empirical studies about the relative predictive performance of the two methods. 相似文献
78.
79.
Wilmin P. Bartolini Catherine M. Bentzley Murray V. Johnston Barbara S. Larsen 《Journal of the American Society for Mass Spectrometry》1999,10(6):521-528
Elucidating structure function relationships of DNA in cellular processes requires fast, reliable methods that can be applied to picomole amounts of sample. Higher order structure can be inferred by distinguishing paired and unpaired regions. It is shown here that enzymatic digestion coupled with product analysis by matrix-assisted laser desorption ionization (MALDI) is able to identify unpaired bases within structured DNA regions. The method is demonstrated with DNA duplexes having a five nucleotide mismatch as a 5' overhang, a 3' overhang, and an internal loop. Exo- and endonuclease digestions are performed under solution conditions (temperature, annealing, and enzyme buffers) which promote base pairing and specific enzyme activity. For each type of mismatch, the length and sequence of the single stranded region can be inferred from MALDI spectra taken as a function of digestion time. 相似文献
80.
Ghizzo A. Bertrand P. Begue M.L. Johnston T.W. Shoucri M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(2):370-378
High-frequency beatwave simulations relevant to the University of California at Los Angeles (UCLA) experiment with relativistic eulerian hybrid Vlasov code are presented. These Hilbert-Masov simulations revealed a rich variety of phenomena associated with the fast particle dynamics induced by beatwave experiment for a high ratio of driver frequency to plasma frequency ωpump/ωplasma ≈33. The present model allows us to extend detailed modeling to frequency ratios greater than the current practical maximum of 10 or so, for Vlasov or particle-in-cell (PIC) codes, by replacing the Maxwell equations by mode equations for the electromagnetic Vlasov code. Numerical results, including beat frequency chirping (i.e., pump frequency linearly decreasing with time), show that the amplitude limit due to relativistic detuning can be enhanced with accelerated particles up to the ultrarelativistic energies with a high-acceleration gradient of more than 25 GeV/m 相似文献