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1.
Lukáš Krásný Petr Pompach Marcela Strnadová Radovan Hynek Karel Vališ Vladimír Havlíček Petr Novák Michael Volný 《Journal of mass spectrometry : JMS》2015,50(6):802-811
We report an MS‐based workflow for identification of phosphorylated peptides from trypsinized protein mixtures and cell lysates that is suitable for high‐throughput sample analysis. The workflow is based on an in situ enrichment on matrix‐assisted laser desorption/ionization (MALDI) plates that were functionalized by TiO2 using automated ion landing apparatus that can operate unsupervised. The MALDI plate can be functionalized by TiO2 into any array of predefined geometry (here, 96 positions for samples and 24 for mass calibration standards) made compatible with a standard MALDI spotter and coupled with high‐performance liquid chromatography. The in situ MALDI plate enrichment was compared with a standard precolumn‐based separation and achieved comparable or better results than the standard method. The performance of this new workflow was demonstrated on a model mixture of proteins as well as on Jurkat cells lysates. The method showed improved signal‐to‐noise ratio in a single MS spectrum, which resulted in better identification by MS/MS and a subsequent database search. Using the workflow, we also found specific phosphorylations in Jurkat cells that were nonspecifically activated by phorbol 12‐myristate 13‐acetate. These phosphorylations concerned the mitogen‐activated protein kinase/extracellular signal‐regulated kinase signaling pathway and its targets and were in agreement with the current knowledge of this signaling cascade. Control sample of non‐activated cells was devoid of these phosphorylations. Overall, the presented analytical workflow is able to detect dynamic phosphorylation events in minimally processed mammalian cells while using only a short high‐performance liquid chromatography gradient. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Jamal Aalaie Mahmood Hemmati Vali Ahmad Sajjadian 《Journal of Macromolecular Science: Physics》2013,52(12):2473-2482
Sulfonated polyacrylamide (SPAA) solutions were prepared and the effects of pressure, polymer concentration, and water temperature, pH and salinity on their rheological behavior were investigated using a concentric cylinder dynamic rheometer equipped with a high pressure cell. According to the rheological flow curves the shear stress of SPAA solutions increased less than in proportion to their shear rates; that is, a shear thinning effect occurred. For polymer solutions containing 15,000 ppm of SPAA, shear viscosity, and stress were nearly insensitive to pressure. However, the shear viscosity and stress of SPAA solutions were affected by temperature and this effect was more evident at lower pressure. The flow curves indicated the shear viscosity and stress of the samples increased with increasing SPAA concentration and pH of the water, but were decreased with increasing water salinity and temperature. 相似文献
4.
A.R. Bahrampour M. Bathaee S. Tofighi A. Bahrampour F. Farman M. Vali 《Optics & Laser Technology》2012,44(7):2026-2031
In this paper, an optical fiber multi-intruder sensor based on polarization maintaining optical fiber (PMF), without any interferometric fiber loop, is introduced. To map the local coordinates of intruders on the beating spectrum of the output modes, radiation from a ramp frequency modulated laser is injected at the input of PMF optical fiber sensor. It is shown that the local coordinates and some characteristics of intruders can be obtained by the measurement of the frequencies and amplitudes of the output mode beating spectrum. Generally the number of beating frequencies is more than the number of intruders. Among the beating frequencies, a group with maximum signal to noise ratio is chosen. The short Fourier denoising method is employed to increase the sensor resolution. Because the output signal is the superposition of finite numbers of discrete frequencies this method is a powerful tool for denoising even for negative signal to noise ratio. 相似文献
5.
H. Bailliet R. Boucheron J.-P. Dalmont Ph. Herzog S. Moreau J.-C. Valière 《Applied Acoustics》2012,73(3):191-197
An experiment has been set up to study multimodal acoustic propagation inside a cylindrical duct in presence of a turbulent mean flow. This paper describes the preliminary work which has been found necessary for assembling the experiment together with first measurement results. In order to set up this experimental facility, a high level acoustic source was developed to generate higher propagating modes in the presence of mean flow. A microphonic antenna was designed for detecting the propagating modes. LDV measurements were performed and synchronous detection was used to extract both the mean flow and the acoustic components of the particle velocity. Results of aeraulic measurements are presented. Then, results of acoustic velocity measurements are compared to results obtained from the microphonic antenna. 相似文献
6.
R. Vali 《Solid State Communications》2009,149(13-14):519-522
The lattice dynamics of room temperature orthorhombic phase of SrHfO3 has been computed, using density functional perturbation theory. The full set of zone center phonon frequencies and infrared reflectivity spectra were reported, providing benchmark theoretical results for the interpretation of future experimental phonon measurements. It is found that the static dielectric constant is relatively anisotropic. This anisotropy has been discussed in relationship to the oscillator strengths and contributions of the lowest IR active modes. 相似文献
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R. Nageswara Rao R. Mastan Vali Dhananjay D. Shinde 《Biomedical chromatography : BMC》2009,23(11):1145-1150
A highly sensitive and selective on‐line two‐dimensional reversed‐phase liquid chromatography/electrospray ionization–tandem mass spectrometry (2D‐LC‐ESI/MS/MS) method was developed and validated to determine rifaximin in rat serum by direct injection. The 2D‐LC‐ESI/MS/MS system consisted of a restricted access media column for trapping proteins as the first dimension and a Waters C18 column as second dimension using 0.1% aqueous acetic acid:acetonitrile as mobile phase in a gradient elution mode. Rifampacin was used as an internal standard. The linear dynamic range was 0.5–10 ng/mL (r2 > 0.998). Acceptable precision and accuracy were obtained over the calibration range. The assay was successfully used in analysis of rat serum to support pharmacokinetic studies. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Mir Ali Farajzadeh Mortaza Ebrahimi Ali Ranji Elham Feyz Vali Bejani Amir Abbas Matin 《Mikrochimica acta》2006,153(1-2):73-78
High performance liquid chromatography (HPLC) and gas chromatography (GC) are introduced for analysis of polymer lubricants
(stearamide, oleamide and erucamide). In the HPLC method, a reverse phase octadecylsilane (ODS) column along with acetonitrile/methanol
(60:40) as a mobile phase were used. Detection of analytes was performed by a UV detector at 202 nm. The analysis time was
less than 8 min. In the GC method, polar capillary column and flame ionization detector (FID) were used for separations and
detection, respectively. The analysis time by GC was longer than HPLC and was about 30 min. Limits of detection, linear range
and repeatability of both methods are similar, but determination of oleamide in real samples by HPLC method is difficult due
to complexity of the initial part of HPLC chromatogram in polyethylene samples. That problem is not observed in the GC method.
Detection limits in both methods for all analytes are lower than 0.003% which are much lower than the amount of lubricants
in commercial polymers (0.05–0.2%). 相似文献
9.
A Field Monte Carlo Formulation for Calculating the Probability Density Function of a Single Scalar in a Turbulent Flow 总被引:3,自引:0,他引:3
Luis Valiño 《Flow, Turbulence and Combustion》1998,60(2):157-172
The probability density function (PDF) formulation of one scalar field undergoing diffusion, turbulent convection and chemical reaction is restated in terms of stochastic fields. These fields are smooth in space as they have a length scale similar to that of the PDF. Their evolution is described by a set of stochastic partial differential equations, which are solved using a finite volume scheme with a stochastic source term. The application of this methodology to a particular flow is shown first for a linear source term, with exact analytical solution for the mean and standard deviation, and then for a nonlinear reaction. 相似文献
10.
R. Vali 《Solid State Communications》2008,145(9-10):497-501
Ab initio density functional theory has been used to study the electronic band structure, (zone center) vibrational modes, and dielectric properties of the crystalline high- perovskite oxide SrZrO3. The frequencies of the normal modes are computed by the linear response technique and then grouped according to their symmetry. The dielectric intensity of each IR-active mode has been determined. It is found that the calculated orientationally averaged static dielectric constant is in good agreement with experiment. 相似文献