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51.
Hernández-Hernández O Montañés F Clemente A Moreno FJ Sanz ML 《Journal of chromatography. A》2011,1218(42):7691-7696
Galactooligosaccharides are non-digestible carbohydrates with potential ability to modulate selectively the intestinal microbiota. In this work, a detailed characterization of oligosaccharides obtained by transgalactosylation reactions of the prebiotic lactulose, by using β-galactosidases of different fungal origin (Aspergillus oryzae, Aspergillus aculeatus and Kluveromyces lactis), is reported. Oligosaccharides of degree of polymerization (DP) up to 6 were detected and quantified by HPLC-ESI MS from a complex mixture produced by transgalactosylation reaction with A. oryzae (GOSLuAo), whereas only carbohydrates up to DP4 and DP5 were found for those obtained from the reaction with β-galactosidases from K. lactis (GOSLuKl) and A. aculeatus (GOSLuAa), respectively. Disaccharides (galactosyl-galactoses and galactosyl-fructoses) and trisaccharides were characterised in the three mixtures by GC-MS as their trimethylsilyl oximes. Galactosyl- and digalactosyl-glycerols were produced during the transgalactosylation reaction of lactulose with β-galactosidases from A. aculeatus and K. lactis, due to the presence of glycerol as enzyme stabiliser. 相似文献
52.
Luis Alberto Rodríguez‐Picn Anna Patricia Rodríguez‐Picn Alejandro Alvarado‐Iniesta 《商业与工业应用随机模型》2019,35(3):504-521
Most modern products that are highly reliable are complex in their inner and outer structures. This situation indicates quality characterization by the interaction of multiple performance characteristics, which motivates the utilization of robust reliability models to obtain robust estimates. It is paramount to obtaining substantial information about a product's life cycle; therefore, when multiple performance characteristics are dependent, it is important to find models that address the joint distribution of performance degradation of such. In this paper, a reliability model for products with 2 fatigue‐crack growth characteristics related to 2 degradation processes is developed. The proposed model considers the dependence among degradation processes by using copula functions considering the marginal degradation processes as inverse Gaussian processes. The statistical inference is performed by using a Bayesian approach to estimate the parameters of the joint bivariate model. A time‐scale transformation is considered to assure monotone paths of the degradation trajectories. The comparison results of the reliability analysis, under both dependent and independent assumptions, are reported with the implementation of the proposed modeling in a case study, which consists of the crack propagation data of 2 terminals of an electronic device. 相似文献
53.
F. Soldevila E. Irles V. Durán P. Clemente Mercedes Fernández-Alonso Enrique Tajahuerce Jesús Lancis 《Applied physics. B, Lasers and optics》2013,113(4):551-558
We present an optical system that performs polarimetric spectral imaging with a detector with no spatial resolution. This fact is possible by applying the theory of compressive sampling to the data acquired by a sensor composed of an analyzer followed by a commercial fiber spectrometer. The key element in the measurement process is a digital micromirror device, which sequentially generates a set of intensity light patterns to sample the object image. For different configurations of the analyzer, we obtain polarimetric images that provide information about the spatial distribution of light polarization at several spectral channels. Experimental results for colorful objects are presented in a spectral range that covers the visible spectrum and a part of the NIR range. The performance of the proposed technique is discussed in detail, and further improvements are suggested. 相似文献
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55.
D. A. Clemente G. Bandoli F. Benetollo A. Marzotto 《Journal of chemical crystallography》1974,4(1):1-14
The crystal and molecular structure of bis(protonated thiamine) tetrachlorodioxouranium(VI), [C12H18ClN4OS]2 UO2Cl4, has been determined from three-dimensional X-ray diffractometer data. The crystals are monoclinic:P21/n,a = 11.199,b = 6.968,c = 23.675 Å, = 97.50°,Z = 2.The structure was determined by Fourier methods and refined by least squares toR = 0.062, using 1675 observed reflections.The structure contains octahedral [UO2 Cl4]2–ions with average U-Cl and U-O distances of 2.67(1) and 1.78(1) Å, respectively.The organic portion of the molecule resembles that of previously reported thiamine structures. The failure to find the hydrogen atoms no doubt prevented our determining either which nitrogen atom is protonated or, with certainty, the hydrogen-bonding distribution. 相似文献
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59.
S.F. Alvarado M. Campagna W. Gudat 《Journal of Electron Spectroscopy and Related Phenomena》1980,18(1):43-49
UHV photoemission studies of Yb metal are reported using synchrotron radiation in the photon energy range 25 < hv < 180 eV, whereby maximum surface sensitivity can be reached. The 4f photoemission spectrum shows a quadruplet structure owing to a superposition of two 4f spin—orbit doublets. One doublet has a very asymmetric lineshape and an extremely narrow lifetime linewidth 2γ? 0.013 eV; this is attributed to bulk emission. The other doublet exhibits almost symmetric lines with a much larger linewidth (0.43 eV FWHM); it has also a larger binding energy by 0.6 ± 0.03 eV. This is attributed as being due to chemically bound Yb atoms located at the surface. The implications of these findings on recent high-resolution photoemission studies of rare earth (RE) metals and their analysis are considered. 相似文献
60.
Tong ML Monfort M Juan JM Chen XM Bu XH Ohba M Kitagawa S 《Chemical communications (Cambridge, England)》2005,(2):233-235
Reaction of di-2-pyridyl ketone (dpk) with nickel acetate and azide in the presence of potassium tert-butylate as a catalytic base generates the title compound, which contains the largest [Ni(mu(1,1)-N3)]6 circles in the discrete ferromagnetically-coupled M(II)-azide cluster family, and shows an unprecedented in situ cyanomethylation of ketone. 相似文献