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971.
Owing to the increasing number of erythropoietin biosimilars being approved, the comparison of different erythropoietin preparations
in the pharmaceutical area is gaining in importance. Erythropoietin has a distinct natural heterogeneity arising from its
glycosylation, which shows strong composition variations. This heterogeneity increases the complexity of the analysis of erythropoietin
considerably, but may also be used to distinguish different preparations. Here, a method is presented for the differentiation
of various erythropoietin preparations by capillary electrophoresis–mass spectrometry and the subsequent application of multivariate
statistics. Relative peak areas of selected intact erythropoietin isoforms were used as variables in principal component analysis
and hierarchical agglomerative clustering. Both of these strategies were suited for the clear differentiation of all erythropoietin
preparations, including marketed products and preproduction preparations, which differ in the manufacturer, the production
cell line, and the batch number. By this means, even closely related preparations were distinguished on the basis of the combined
information on the antennarity, the sialoform, and the acetylation of the observed isoforms. 相似文献
972.
J Li M Hermann G Frenking C Jones 《Angewandte Chemie (International ed. in English)》2012,51(34):8611-8614
Taking the fizz out: A digermyne compound with a Ge?Ge single bond has been shown to quantitatively reduce CO(2) to CO at temperatures as low as -40?°C. The mechanism of this unprecedented reaction has been probed by spectroscopic and computational techniques and involves a metastable intermediate (see picture; Ar*=C(6) H(2) {C(H)Ph(2) }(2) Me-2,6,4). 相似文献
973.
J Streuff M Feurer P Bichovski G Frey U Gellrich 《Angewandte Chemie (International ed. in English)》2012,51(34):8661-8664
Reduction, please! The title reaction affords α-hydroxyketones, a common structural motif in biologically active natural products, in good yields and high enantioselectivities at room temperature. The commercially available ansa-titanocene 1 was found to be an efficient catalyst for this process, which presumably proceeds by addition of a ketyl radical to a nitrile. 相似文献
974.
975.
976.
977.
978.
Tew MW Nachtegaal M Janousch M Huthwelker T van Bokhoven JA 《Physical chemistry chemical physics : PCCP》2012,14(16):5761-5768
The catalytically active phase of silica-supported palladium catalysts in the selective and non-selective hydrogenation of 1-pentyne was determined using in situ X-ray absorption spectroscopy at the Pd K and L(3) edges. Upon exposure to alkyne, a palladium carbide-like phase rapidly forms, which prevents hydrogen to diffuse into the bulk of the nano-sized particles. Both selective and non-selective hydrogenation occur over carbided particles. The palladium carbide-like phase is stable under reaction conditions and only partially decomposes under high hydrogen partial pressure. Non-selective hydrogenation to pentane is not indicative of hydride formation. The palladium carbide phase was detected in the EXAFS analysis and the K edge XANES showed representative features. 相似文献
979.
980.
M Albrecht Y Shang K Hasui V Gossen G Raabe K Tahara Y Tobe 《Dalton transactions (Cambridge, England : 2003)》2012,41(31):9316-9322
Triangular triscatechol ligands are prepared in facile reaction sequences. The catechol units are either bound to the triangular backbone through their 3- or 4-position. With titanium(IV) ions, the ligands form metallosupramolecular M(4)L(4) tetrahedra which are characterized by ESI MS and proton NMR. Quantum-chemical calculations reveal that connectivity at the catechol in the 3-position results in highly condensed structures while attachment in the 4-position affords container molecules providing huge internal cavities. 相似文献