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121.
Muriel De Bock Marie-Alice Meuwis Tran Quang Minh Jean-Paul Chapelle Michel Malaise Marianne Fillet 《Talanta》2010,82(1):245-594
In most diseases, the clinical need for serum/plasma markers has never been so crucial, not only for diagnosis, but also for the selection of the most efficient therapies, as well as exclusion of ineffective or toxic treatment. Due to the high sample complexity, prefractionation is essential for exploring the deep proteome and finding specific markers.In this study, three different sample preparation methods (i.e., highly abundant protein precipitation, restricted access materials (RAM) combined with IMAC chromatography and peptide ligand affinity beads) were investigated in order to select the best fractionation step for further differential proteomic experiments focusing on the LMW proteome (MW inferior to 40,000 Da). Indeed, the aim was not to cover the entire plasma/serum proteome, but to enrich potentially interesting tissue leakage proteins. These three methods were evaluated on their reproducibility, on the SELDI-TOF-MS peptide/protein peaks generated after fractionation and on the information supplied.The studied methods appeared to give complementary information and presented good reproducibility (below 20%). Peptide ligand affinity beads were found to provide efficient depletion of HMW proteins and peak enrichment in protein/peptide profiles. 相似文献
122.
Tianfang Wang T. T. Nha Tran Denis Scanlon Hayley J. Andreazza Andrew D. Abell John H. Bowie 《Rapid communications in mass spectrometry : RCM》2011,25(18):2649-2656
It has been shown previously that [M–H]– anions of small peptides containing two phosphate residues undergo cyclisation of the phosphate groups, following collision‐induced dissociation (CID), to form a characteristic singly charged anion A (H3P2O7–, m/z 177). In the present study it is shown that the precursor anions derived from the diphosphopeptides of caerin 1.1 [GLLSVLGSVAKHVLPHVVPVIAEHL(NH2)] and frenatin 3 [GLMSVLGHAVGNVLGGLFKPKS(OH)] also form the characteristic product anion A (m/z 177). Both of the precursor peptides show random structures in water, but partial helices in membrane‐mimicking solvents [e.g. in d3‐trifluoroethanol/water (1:1)]. In both cases the diphosphopeptide precursor anions must have flexible conformations in order to allow approach of the phosphate groups with consequent formation of A: for example, the two pSer groups of 4,22‐diphosphofrenatin 3 are seventeen residues apart. Finally, CID tandem mass spectrometric (MS/MS) data from the [M–H]– anion of the model triphosphoSer‐containing peptide GpSGLGpSGLGpSGL(OH) show the presence of both product anions A (m/z 177) and D (m/z 257, H4P3O10–). Ab initio calculations at the HF/6‐31+G(d)//AM1 level of theory suggest that cyclisation of the three phosphate groups occurs by a stepwise cascade mechanism in an energetically favourable reaction (ΔG = ?245 kJ mol–1) with a maximum barrier of +123 kJ mol–1. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
123.
124.
Phat L. Tran Jessica R. Gamboa David J. You Jeong-Yeol Yoon 《Analytical and bioanalytical chemistry》2010,398(2):759-768
An alternative approach for fabricating a protein array at nanoscale is suggested with a capability of characterization and/or
localization of multiple components on a nanoarray. Fluorescent micro- and nanobeads each conjugated with different antibodies
are assembled by size-dependent self-assembly (SDSA) onto nanometer wells that were created on a polymethyl methacrylate (PMMA)
substrate by electron beam lithography (EBL). Antibody-conjugated beads of different diameters are added serially and electrostatically
attached to corresponding wells through electrostatic attraction between the charged beads (confirmed by zeta potential analysis)
and exposed p-doped silicon substrate underneath the PMMA layer. This SDSA method is enhanced by vibrated-wire-guide manipulation
of droplets on the PMMA surface containing nanometer wells. Saturation rates of antibody-conjugated beads to the nanometer
patterns are up to 97% under one component and 58–70% under two components nanoarrays. High-density arrays (up to 40,000 wells)
could be fabricated, which can also be multi-component. Target detection utilizes fluorescence resonance energy transfer (FRET)
from fluorescent beads to fluorescent-tagged secondary antibodies to Octamer-4 (Oct4), which eliminates the need for multiple
steps of rinsing. The 100 nm green beads are covalently conjugated with anti-Oct4 to capture Oct4 peptides (39 kDa); where
the secondary anti-Oct4 and F(ab)2 fragment of anti-gIgG tagged with phycoerythrin are then added to function as an indicator of Oct4 detection. FRET signals
are detected through confocal microscopes, and further confirmed by Fluorolog3 spectrofluorometer. The success rates of detecting
Oct4 are 32% and 14% of the beads in right place under one and two component nanoarrays, respectively. Ratiometric FRET is
used to quantify the amount of Oct4 peptides per each bead, which is estimated about 2 molecules per bead. 相似文献
125.
126.
We give a new proof of the structure theorem for PSH—algebras, and of a formula for primitives 相似文献
127.
A numerical method is presented for form-finding of cable-strut structures. The topology and the types of members are the only information that is required in this form-finding process. Dummy members are used to transform the cable-strut structure with supports into self-stressed system without supports. The requirement on rank deficiencies of the force density and equilibrium matrices for the purpose of obtaining a non-degenerate d-dimensional self-stressed structure has been explicitly discussed. The spectral decomposition of the force density matrix and the singular value decomposition of the equilibrium matrix are performed iteratively to find the feasible sets of nodal coordinates and force densities which satisfy the minimum required rank deficiencies of the force density and equilibrium matrices, respectively. Based on numerical examples it is found that the proposed method is very efficient, robust and versatile in searching self-equilibrium configurations of cable-strut structures. 相似文献
128.
129.
Nguyen To Nhu Jose M. R. Sanjurjo Tran Van An 《Proceedings of the American Mathematical Society》1997,125(10):3089-3098
In this second part of our paper, we apply the result of Part 1 to show that the compact convex set with no extreme points, constructed by Roberts (1977), is an AR.
130.
Tran Dan Thu 《Journal of Combinatorial Theory, Series A》2007,114(8):1504-1514
The powerful AZ identity is a sharpening of the famous LYM-inequality. More generally, Ahlswede and Zhang discovered a generalization in which the Bollobás inequality for two set families can be lifted to an identity.In this paper, we show another generalization of the AZ identity. The new identity implies an identity which characterizes the deficiency of the Bollobás inequality for an intersecting Sperner family. We also give some consequences relating to Helly families and LYM-style inequalities. 相似文献