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81.
In this study, we developed a novel microwave-assisted protein preparation and digestion method for matrix-assisted laser
desorption/ionization (MALDI) time-of-flight mass spectrometry analysis and identification of proteins that involves using
conductive carbon tape as a sample platform for sample preparation (reduction and alkylation) and digestion under microwave
heating and as a plate for MALDI analysis. This method allows for the enzymatic digestion products of proteins to be directly
analyzed by MALDI mass spectrometry and results in a marked reduction in sample loss. Our protocol requires only a small volume
(1 μL) of reaction solvent, which increases the frequency of enzyme-to-protein contact, thereby resulting in more efficient
digestion of sample than conventional in-solution digestion methods. To test this protocol, we used magnetic iron (II, III)
oxide nanoparticles as concentrating probes to enrich phosphopeptides from a mixture of peptides in enzymatically digested
protein samples. We found that the one-pot on-tape-based protein preparation and digestion under microwave heating combined
with the on-tape-based enrichment method not only dramatically reduced the time required for phosphopeptides analysis but
also allowed for the simultaneous identification of phosphoproteins. The advantages of our protocol include ease of use, high
digestion efficiency, high specificity, and rapid (15 min) identification of proteins and enrichment of phosphopeptides in
a mixture of enzymatically digested protein samples. 相似文献
82.
The amounts of Cu(II), Zn(II), and phosphate sorbed from single- and binary-sorbate systems on goethite (alpha-FeOOH) were measured. Experiments were carried out as a function of equilibrium pH (2-7), sorbate concentration (0.21-1.57 mM), and temperature (15-35 degrees C). The aqueous phase contained 0.1 M NaNO3 to maintain ionic strength constant. A convenient method was used to obtain sorption isotherms of single Cu(II), Zn(II), and phosphate at a fixed equilibrium pH, which could be well described by the Langmuir equation. Thermodynamic parameters for the sorption of single Cu(II) and phosphate including the free energies, isosteric enthalpies, and entropies were determined. In contrast to the single-sorbate systems, the sorption of metals was inhibited in the binary Cu(II)-Zn(II) system, whereas the sorption of both sorbates was enhanced in the binary Cu(II)-phosphate system under the conditions studied. The validity of the Langmuir competitive model for the prediction of the sorption isotherms in a binary Cu(II)-Zn(II) system was also discussed. 相似文献
83.
Jer-Nan Juang 《Nonlinear dynamics》2005,39(1-2):79-94
The objective of this paper is to describe a new method for identification of a continuous-time multi-input and multi-output bilinear system. The approach is to make judicious use of the linear-model properties of the bilinear system when subjected to a constant input. Two steps are required in the identification process. The first step is to use a set of pulse responses resulting from a constant input of one sample period to identify the state matrix, the output matrix, and the direct transmission matrix. The second step is to use another set of pulse responses with the same constant input over multiple sample periods to identify the input matrix and the coefficient matrices associated with the coupling terms between the state and the inputs. Numerical examples are given to illustrate the concept and the computational algorithm for the identification method. 相似文献
84.
K. Bajema R. Merlin F.-Y. Juang S.-C. Hong J. Singh P.K. Bhattacharya 《Superlattices and Microstructures》1987,3(6)
We report on a Raman scattering study of the electric-field dependence of c0 → c1 intersubband transitions of
electrons in a 264 Å GaAs- Al0.3Ga0.7As quantum-well structure. The measured Stark shifts are in very good agreement with theoretical predictions. The intensity of the intersubband peak increases rapidly with applied field due to parity-mixing. In contrast to the enhanced broadening shown by excitation resonances, the width of c0 → c1 is nearly independent of the field. This feature is attributed to effects of structural disorder. 相似文献
85.
Shang-Hui Yang Jian-Shian Lin Fuh-Shyang Juang Ding-Chin Chou Ming-Hua Chung Chen-Ming Chen Lung-Chang Liu 《Current Applied Physics》2013,13(5):931-934
In this paper, white light emitting diodes (LEDs) with good color rendering indices (CRI) and high luminous efficiencies have been fabricated by the encapsulation of mixed and double-deck phosphors. Experimental results revealed that white LEDs with the encapsulation of double-deck phosphors exhibited better CRI and higher luminous efficiencies than those with the encapsulation of mixed phosphors because no secondary excitation took place. The hue, CRI, and luminous efficiencies of white LEDs with double-deck phosphors under 200 mA were CIEx,y = (0.357, 0.348), 90, and 62.3 lm/W, respectively while the hue, CRI, and luminous efficiencies of white LEDs with mixed phosphors under 200 mA were CIEx,y = (0.366, 0.354), 89, and 56.5 lm/W, respectively. 相似文献
86.
S.-A. Ku C.-W. Luo H.-L. Lio K.-H. Wu J.-Y. Juang A. I. Potekaev O. P. Tolbanov S. Yu. Sarkisov Yu. М. Andreev G. V. Lanskii 《Russian Physics Journal》2008,51(10):1083-1089
Transmission spectra and phase matching conditions for second harmonic generation in GaSe1–x
S
x
(0 < x ≤ 0.4) solid solution crystals are experimentally investigated. An algorithm is suggested and dispersion equations are derived
that allow the phase matching angles describing best the available experimental data to be estimated as a function of the
mixing ratio x.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 80–85, October, 2008. 相似文献
87.
88.
Five series of asymmetric diphenyldiacetylenes containing a single fluorine, two fluorines or a trifluoromethyl group at one end and an alkyl, alkyloxy or alkenyloxy group on the other end, were prepared and characterized. Most of the 4-alkylphenyl-4'-fluorophenyldiacetylenes, 4-alkyloxyphenyl-4'-fluorophenyldiacetylenes and 4-alkenyloxyphenyl-4'-fluorophenyldiacetylenes obtained exhibit an enantiotropic nematic phase and no smectic phase. However, most of the 4-alkyl-3', 4'-difluorodiphenyldiacetylenes, 4-alkenyloxy-3',4'-difluorodiphenyldiacetylenes and 4-alkyl-4'-trifluoromethyldiphenyldiacetylenes show no mesomorphic behaviour. The effects of alkyl, alkyloxy, alkenyloxy, fluoro, 3,4-difluoro and trifluoromethyl end groups on the mesomorphic behaviour of the diphenyldiacetylenes prepared are discussed. 相似文献
89.
Several methods can be used to improve the enrichment of phosphorylated proteins. In this paper, phosphopeptides were enriched using magnetic iron(II,III) oxide (magnetite, Fe(3)O(4)) nanoparticles (NPs) on a radiate microstructure silicon chip and then analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) without further purification processes. We have developed a radiate microstructure chip on which samples can be concentrated for analysis by MALDI-TOFMS. The phosphoprotein digests and magnetic iron oxide NPs aqueous solution were deposited onto the central zone of the radiate microstructure silicon chip and enabled the on-chip enrichment of phosphopeptides. Microscopic analysis confirmed that the applied samples were confined to the central zone. Sample spots focused on the chip were much smaller than those on an unmodified plate with the same total volume. Different additives were used and optimized processes were performed to minimize non-phosphopeptides interference. These data collectively demonstrate that our on-chip phosphopeptide enrichment protocol is a rapid and easy-to-use method for phosphoproteome analysis. 相似文献
90.