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Summary Four immunological assays (RIA, ELISA, EMIT, FPIA) for digoxin were characterized with respect to reproducibility, detection limit, selectivity, and accuracy, followed by the comparison with HPLC. Afterwards the serum samples of nearly 60 patients were analyzed by these five methods.It could be shown, that the reproducibility at 2 g/l was fairly good for all methods. Reliable analysis in the lower concentration range (< 1 g/l) was difficult with two assays, because of insufficient detection limits. There was a marked cross-reactivity to other digitalis glycosides. Moreover, correlation between the immunological methods and in comparison to the HPLC-method was low.
Bestimmung von Digoxin in HumanserumVergleich einiger immunologischer Assays mit einer vorgeschlagenen HPLC-Referenzmethode相似文献
23.
Hellmut Haberland Bernd von Issendorff Ji Yufeng Thomas Kolar Gregor Thanner 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,26(1):8-12
The change of the cohesive energy and the optical absorption spectra of small singly sized Hg clusters is discussed. The cohesive energy allows one to determine the different regimes of chemical bonding. The optical spectra show an abrupt transition to a collective, plasmon-like absorption as a function of increasing cluster size. The position of the one plasmon peak is: 1) independent of the charge state, 2) nearly independent of cluster size, and 3) agrees with that of the classical Mie plasmon calculated from the experimental dielectric constants. The width of the plasmon peaks is discussed. A strong influence of electronic correlations on the cluster size dependence of the oscillator strength is observed. 相似文献
24.
Hellmut Hoffmann Heinz Förster Grikor Tor-Poghossian 《Monatshefte für Chemie / Chemical Monthly》1969,100(1):311-315
Zusammenfassung N-Fluorsulfonylisocyanat bildet mit Triphenylphosphin, Phosphorigsäuretrisdimethylamid und Phosphorigsäuretriäthylester 11-Addukte unterschiedlicher Stabilität. Die Bildung von N-Fluorsulfonylcarbodiimiden aus N-Fluorsulfonylisocyanat und dem Phospholenoxid 7 gelingt nicht, da die Reaktion auf der Stufe des N-Fluorsulfonylphospholenimins stehenbleibt.
Reaction of N-fluorosulfonyl isocyanate with phosphorus compounds
11-adducts of different stability are the products of the interaction of N-fluorosulfonylisocyanate with triphenylphosphine, phosphorous acid tris(dimethylamide), and triethyl phosphite. No N-fluorosulfonylcarbodiimides are formed from N-fluorosulfonylisocyanate and phospholene oxide (7), since the reaction does not proceed beyond the intermediate N-fluorosulfonylphospholene imine.相似文献
25.
Hellmut Keiter 《Zeitschrift für Physik B Condensed Matter》1976,23(1):37-44
The system of six coupled, nonlinear, singular integral equations, devised by Suhl to treat the problem of a spin 1/2 magnetic impurity in a finite magnetic field is shown to be reducible to a single integral equation. Analytic properties and symmetries of the system are discussed, which may serve as a guideline for numerical studies of the final integral equation. The first few steps of an iteration in terms of the magnetic field strength are carried out analytically.On leave from the Institut für Theoretische Physik der Universität Köln. 相似文献
26.
Silvia H. Santagneli Matthias T. Rinke Younes Messaddeq Hellmut Eckert 《Journal of Non》2011,357(10):2126-2131
Glasses were prepared in the pseudo-binary system (1 − x)AgPO3-xWO3 (0≤ × ≤ 0.6 mol%). The structural evolution of the vitreous network was studied as a function of composition by thermal analysis, Fourier Transform Infrared spectroscopy (FTIR), Raman scattering, high resolution 31P solid state NMR and XANES at the W-L1 absorption edge. For compositions with x ranging from 0 to 0.5 a pronounced increase in the glass transition temperature is observed, suggesting a significant increase in the glass network connectivity. At the same time Raman spectra indicate that tungsten atoms are linked to non-bridging oxygen atoms (W-O- or W=O bonded species) whereas the 31P MAS-NMR spectra indicate the successive formation of new P-O-W linkages. The formation of some anionic tungsten sites (if these are revealed by the presence of W-O terminal bonds) implies an increase in the average degree of polymerization of the phosphate network, which is consistent with the compositional evolution of the 31P MAS-NMR spectra at low x values. For higher x-values, the Raman spectra indicate the presence of W-O-W linkages. W-L1 XANES data indicate that at least 90% of tungsten atoms are octahedrally coordinated. 相似文献
27.
Brinkmann C Faske S Vogel M Nilges T Heuer A Eckert H 《Physical chemistry chemical physics : PCCP》2006,8(3):369-378
The relation between structure and ion dynamics in the three polymorphs of Ag(5)Te(2)Cl has been investigated using (109)Ag, (125)Te, and (35)Cl NMR spectroscopies. Specifically, the influence of the structural phase transitions observed near 240 K (P2(1)/c<-->P2(1)/n) and near 332 K (P2(1)/n<-->I4/mcm) upon silver ion mobilities has been studied by temperature dependent (109)Ag NMR lineshapes and spin-lattice relaxation times. While the superionic high temperature phase alpha-Ag(5)Te(2)Cl is characterized by a molten cationic sublattice, fast ion dynamics in the medium-temperature phase beta-Ag(5)Te(2)Cl occurs in spatially restricted regions comprising all the crystallographically distinct silver sites. Temperature dependent magic-angle-spinning linewidths yield an activation energy of 0.38 eV, consistent with 0.44 eV measured from dc electric conductivities. For the low-temperature gamma-modification, results of two- and three-time (109)Ag correlation spectroscopies provide a detailed insight into the nature of the silver ionic hopping motion. Temperature dependent jump rates measured by two-time correlation functions yield an activation energy E(a)= 0.48 eV. (109)Ag NMR three-time correlation functions indicate that the non-exponential relaxation behavior of the silver ions can be attributed to a broad distribution of jump rates rather than correlated forward-backward jumps. Nevertheless, all the silver ions are mobile down to temperatures of about 185 K. 相似文献
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29.
Xiaoming Jie Constantin G. Daniliuc Robert Knitsch Michael Ryan Hansen Hellmut Eckert Sebastian Ehlert Stefan Grimme Gerald Kehr Gerhard Erker 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(3):892-896
A new six‐membered cyclic frustrated phosphane/borane Lewis pair was liberated from its HB(C6F5)2 adduct by treatment with vinylcyclohexane. The system is an active frustrated Lewis pair that undergoes cycloaddition reactions with suitable π reagents and it splits dihydrogen. At room temperature in solution the new compound is a monomer, however, in the crystal and in solution at low temperature it aggregates to a thermodynamically favoured supramolecular macrocyclic cyclooctamer. 相似文献
30.
Jennifer Malberg Michael Bodensteiner Daniel Paul Thomas Wiegand Hellmut Eckert Robert Wolf 《Angewandte Chemie (International ed. in English)》2014,53(10):2771-2775
Molecular squares are among the most common supramolecular architectures, but phospha‐organometallic complexes have not been used as building blocks for this type of structure. Herein we describe the formation of the molecular square [Au{Co(P2C2tBu2)2}]4 ( 1 ) by the self‐assembly of anionic 1,3‐diphosphacyclobutadiene cobalt complexes and gold(I) cations. The X‐ray crystallographic determination of the molecular structure of 1 is complemented by solid‐state 31P and 13C NMR investigations. High‐level DFT calculations confirm the assignment of the 31P and 13C NMR resonances. 相似文献