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41.
N-glycosylation is a common protein modification process, which affects a number of properties of proteins. Little is known about the distribution of N-glycosylation sequons, for example, the distance between glycosylated sites and their position in the protein primary sequence. Using a large set of experimentally confirmed eukaryotic N-glycoproteins we analyzed the relative position and distribution of sequons. N-Glycosylation probability was found to be lower in the termini of protein sequences compared to the mid region. N-glycosylated sequons were found much farther from C terminus compared to the N-terminus of the protein sequence and this effect was more pronounced for NXS sequons. The distribution of sequons, modeled based on balls-in-boxes classical occupancy, showed a near-maximum probability. Considerable proportion of sequons was found within a distance of ten amino acids, indicating that the steric hindrance was not a key factor in protein N-glycosylation. Interestingly, the distribution of all sequons present in N-glycoproteins showed a pattern very similar to that of glycosylated sequons. The results indicate that protein N-glycosylation chiefly follows a random design. 相似文献
42.
43.
Various second-order properties for H2O have been computed using a near Hartree-Fock gaussian wave function and a coupled Hartree-Fock scheme. Satisfactory agreement with experimental data is obtained for vibrational frequencies and for magnetic properties. The calculated electric polarizability only accounts for 64 per cent of the experimental value. 相似文献
44.
45.
Z. V. Popović C. Thomsen M. Cardona R. Liu G. Stanišić W. König 《Zeitschrift für Physik B Condensed Matter》1988,72(1):13-16
We report both Raman and infrared reflectivity spectra of M2Cu2O5 (M=Y, Ho) at room temperature in the spectral range of 30–1000 cm–1.37 (31) ir and 18 (15) Raman active modes of Y2Cu2O5 (Ho2Cu2O5) are observed. A factor group analysis has been performed to identify the symmetries of the observed modes. Comparing the vibrational spectra of these compounds we conclude that the phonons above 300 cm–1 originate from the Cu–O vibrations and those under 300 cm–1 from M–O vibrations.Alexander von Humboldt Foundation fellow 相似文献
46.
H.C. Mastwijk M. van Rijnbach J.W. Thomsen P. van der Straten A. Niehaus 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,4(2):131-137
This paper presents an experimental investigation of cold collisions between metastable helium atoms in an optical trap at
1 mK. Penning (PI) and associative (AI) ionization reactions are distinguished using a mass spectrometer and studied under
influence of near resonant laser light. Dramatic enhancement, by more than a factor 15, of the ion rate is observed when the
laser is tuned close to resonance. Experimental findings are well-described, on an absolute scale, by model predictions.
Received: 9 February 1998 / Revised: 4 May 1998 / Accepted: 14 May 1998 相似文献
47.
The dual-plasma atomic fluorescence/atomic emission spectrometer (ASIA spectrometer) is described and the detection limits for several elements in both the fluorescence and the emission mode are presented and compared directly. The detection limits for the non-refractory elements are, in general, better in fluorescence than emission While for the refractory elements the converse is true, but all are in the ng ml−1 range. Growth curves for a refractory and a non-refractory element are presented and evaluated. 相似文献
48.
Steen Honoré Hansen Per Helboe Mogens Thomsen 《Trends in analytical chemistry : TRAC》1985,4(9):233-237
A new approach to reversed-phase high-performance liquid chromatography has been developed and investigated in some detail. Bare silica is used as the column packing material with an aqueous eluent containing a buffer, an organic solvent as the modifier and a long-chain quaternary ammonium ion. The eluent exhibits a high affinity to the silica surface at pH values above 5, thus, dynamically, forming a nonpolar stationary phase. 相似文献
49.
C. Thomsen P. Wiggers H. Ring-Larsen E. Christiansen J. Dalh j O. Henriksen P. Christoffersen 《Magnetic resonance imaging》1992,10(6):867-879
A total of 4302 healthy blood donors were screened for elevated serum ferritin and transferrin saturation. Fifteen had increased serum ferritin at a follow-up examination. Five relatives of these donors also entered the study. Eleven patients had elevated liver iron concentrations, while five had normal liver iron concentrations. The R2 relaxation rate in the liver was first measured with a conventional multi-spin-echo imaging sequence, and then by a volume-selective spectroscopic multi-spin-echo sequence, in order to achieve a minimum echo time of 4 msec. No correlation was found between the relaxation rate R2 and the liver iron concentration, when R2 was calculated from the imaging data. Multi-exponential transverse relaxation could be resolved when the spectroscopic sequence was used. A strong correlation between the initial slope of the relaxation curve and the liver iron concentration was found (r = 0.90, p < 0.001). Signal intensity ratios between liver and muscle were calculated from the first three echoes in the multi-echo imaging sequence, and from a gradient echo sequence. A strong correlation between the logarithm of the signal intensity ratios and the liver iron concentration was found. Although both spectroscopic T2 relaxation time measurements and signal intensity ratios could be used to quantify liver iron concentration, the gradient echo imaging seemed to be the best choice. Gradient echo imaging could be performed during a single breath hold, so motion artifacts could be avoided. The accuracy of liver iron concentration estimates from signal intensity ratios in the gradient echo images was about 35%. 相似文献
50.
Back Cover: Co‐existence of Two Different α‐Synuclein Oligomers with Different Core Structures Determined by Hydrogen/Deuterium Exchange Mass Spectrometry (Angew. Chem. Int. Ed. 29/2014)
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