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151.
J. Chamón P. C. Gutierrez J. Barrio A. Climent-Font M. Arroyo 《Applied Physics A: Materials Science & Processing》2010,99(2):377-381
A set of fragments of metallic artefacts from the medieval period excavated from Ciudad Real in Spain has been studied. The
objects are gilded copper buckles with a champlevé enamelling decoration. The composition of predominantly blue-coloured enamels has been analysed using three non-destructive
techniques, SEM-EDAX (scanning electron microscopy coupled with energy-dispersive X-ray analysis), X-ray fluorescence (XRF)
and PIXE (particle-induced X-ray emission). Analyses show that Co is responsible for the blue colour. The results of the two
techniques are compared, as well as the main components which constitute the enamel. Analyses suggest that Cu is responsible
for red colour. 相似文献
152.
153.
We developed a constituent quark-diquark model for the nucleon and its resonances using a harmonic oscillator potential for
the interaction. The effects due to relativistic kinetic energy correction are studied. Finally, charge form factor of the
model is calculated and compared with experimental data.
相似文献
154.
155.
Soares CR Camargo IM Morganti L Gimbo E Ezequiel de Oliveira J Legoux R Ferrara P Bartolini P 《Journal of chromatography. A》2002,955(2):229-236
Reversed-phase high-performance liquid chromatography methodology for the determination of human prolactin (hPRL) in bacterial periplasmic space or in purified preparations has been developed. The technique, based on the high hydrophobicity of the hPRL molecule, allows its separation from the bulk of bacterial proteins. The precision for periplasmic shock fluid analysis was characterized by relative standard variations of 3-7% for intra-day and of 3-25% for inter-day determinations. Accuracy, evaluated by recovery tests, was of the order of 90%, a calibration curve being constructed with the use of a lyophilized osmotic shock fluid extract, which provided a stable, readily prepared internal reference. Sensitivity was of the order of 0.5 microg of hPRL. The methodology developed also provided a tool for comparing the hydrophobicity of glycosylated and non-glycosylated prolactin molecules obtained from several different species and of different preparations of native or biosynthetic human prolactin. 相似文献
156.
Xu X MacLean EJ Teat SJ Nieuwenhuyzen M Chambers M James SL 《Chemical communications (Cambridge, England)》2002,(1):78-79
Addition of anionic benzylsulfate dendrons to dynamic mixtures of Ag+ and triphosphine ligands results in the assembly of loosely-bonded cage-core dendrimers. 相似文献
157.
158.
159.
Viornery L Saliba C Daskiewicz JB Bayet C Comte G Fenet B Gutierrez G Barron D 《Chemical & pharmaceutical bulletin》2000,48(11):1768-1770
Phytochemical investigation of the leaves of Umbilicus pendulinus afforded in addition to 2-O-caffeoyl malate, isoquercitrin and Z-venusol, the new isomer E-venusol. Special NMR experiments were carried out to elucidate the configuration of the two latter compounds. 相似文献
160.
Background: The translation or stability of the mRNAs from ferritin, m-aconitase, erythroid aminoevulinate synthase and the transferrin receptor is controlled by the binding of two iron regulatory proteins to a family of hairpin-forming RNA sequences called iron-responsive elements (IREs). The determination of higher-solution nuclear magnetic resonance (NMR) structures of IRE variants suggests an unusual hexaloop structure, leading to an intra-loop G-C base pair and a highly exposed loop guanine, and a special internal loop/bulge in the ferritin IRE involving a shift in base pairing not predicted with standard algorithms.Results: Cleavage of synthetic 55- and 30-mer RNA oligonucleotides corresponding to the ferritin IRE with complexes based on oxoruthenium(IV) shows enhanced reactivity at a hexaloop guanine and at a guanine adjacent to the internal loop/bulge with strong protection at a guanine in the internal loop/bulge. These results are consistent with the recent NMR structures. The synthetic 55-mer RNA binds the iron-regulatory protein from rabbit reticulocyte lysates. The DNA analogs of the 55- and 30-mers do not show the same reactivity pattern.Conclusions: The chemical reactivity of the guanines in the ferritin IRE towards oxoruthenium(IV) supports the published NMR structures and the known oxidation chemistry of the metal complexes, The results constitute progress towards developing stand-alone chemical nucleases that reveal significant structural properties and provide results that can ultimately be used to constrain molecular modeling. 相似文献