排序方式: 共有14条查询结果,搜索用时 15 毫秒
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G. Heidecke G. Stork J. G. Schindler M. v. Gülich W. Schmid H. Maier H. -O. Lindt und D. Sailer 《Fresenius' Journal of Analytical Chemistry》1980,301(5):406-409
Zusammenfassung Für die Na+-, K+- und Ca2+ -Bestimmung mit ionenselektiven Diskelektroden im medizinischen Bereich empfiehlt sich die Zweipunkteichung. Die mit diesem Verfahren erzielbare Reproduzierbarkeit wird theoretisch aufgrund des Ablesefehlers am Meßinstrument berechnet und mit experimentellen Werten verglichen. Die theoretisch berechneten und experimentellen Standardabweichungen liegen für 1-wertige Ionen bei 0,3 % und für 2-wertige bei 0,6 %. Die Genauigkeit wird nicht durch die Elektroden, sondern die gegenwärtig verfügbaren Meßgeräte begrenzt.
On the reproducibility of Na+-, K+- and Ca2+-selective disc electrodes as dependent on the indicating error of the potential measuring device
Summary In clinical analysis it is recommendable to use a two-point calibration for the determination of Na+, K+ and Ca2+ ions by ion-selective disc electrodes. The accuracy, which can be obtained by this calibration method, is treated theoretically, and the results are compared with experimental data. Theoretical and experimental standard deviations are in very good agreement, with 0.3 % for Na+ and K+ and 0.6 % for Ca2+. The precision is limited by the measuring instrument and not by the disc electrodes.
Wir danken dem Fonds der Chemischen Industrie, dem Bundesministerium für Forschung und Technologie der Bundesrepublik Deutschland und der Dr. E. Fresenius KG, Bad Homburg v.d.H., für die Unterstützung der Arbeiten. 相似文献
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Dendrimer chemistry is an attractive concept for mimicry of the highly branched character of the bioactive carbohydrates found as part of a cell's sugar coat, called the glycocalyx. Glycodendrimers have thus been used to study biological processes occurring on cell surfaces, such as bacterial adhesion. This paper details a new approach in glycodendrimer synthesis, in which a 3,6-diallylated carbohydrate is utilised as core molecule, hydroboration-oxidation is the activating step, and glycosylation with branched and unbranched sugar trichloroacetimidates is used for dendritic growth. To obtain pure dendritic pseudo-tri- and -heptasaccharides in good yields, radical addition of mercaptoethanol to peripheral double bonds was also evaluated with great success. A collection of six new hyperbranched glycodendrons was tested for their potential as inhibitors of type 1 fimbriae-mediated bacterial adhesion in an ELISA and the results were interpreted with regard to sugar valency and spacer characteristics. 相似文献
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G. Heidecke J. Kropf G. Stork und J. G. Schindler 《Fresenius' Journal of Analytical Chemistry》1980,303(5):364-370
Zusammenfassung Bei Diskelektroden bzw. Coated-Wire-Elektroden mit Pt als Festkontakt lÄ\t sich das innere Referenzsystem als Gaselektrode beschreiben. Das ursprünglich im Me\betrieb vorliegende Pt/O2-System kann durch SÄttigen der Me\lösung mit H2 in eine Pt/H2-Halbzelle umgewandelt werden. Theoretische AnsÄtze für die Gasdiffusion durch die Polymerelektrodenmembran werden miteinander verglichen. Die gemessenen Potentialeinstellkurven dienen zur Berechnung von Diffusionskoeffizienten für O2 und H2. Eine exakte Beschreibung der experimentellen Befunde sollte das Auftreten von Mischpotentialen berücksichtigen.
Contribution to the function of the internal metallic lead in ion-selective disk electrodes. II
Summary The internal reference system of disk electrodes or coated-wire electrodes with direct contact of Pt wire to the ion-selective membrane can be described as a gaseous electrode. Under normal conditions there exists a Pt/O2-system, which can be transferred into a stable Pt/H2-system by saturating the solution with hydrogen. Several calculations of the diffusion of gas through the PVC-membrane are compared in order to get coefficients of diffusion for oxygen and hydrogen in ion-selective membranes. The results show that mixed potentials have to be taken into consideration.
Wir danken dem Fonds der Chemischen Industrie für die Unterstützung der Arbeiten. 相似文献
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Rising TW Heidecke CD Moir JW Ling Z Fairbanks AJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(21):6444-6464
A complete series of oxazoline di-, tri-, tetra-, and hexasaccharides, corresponding to the core sections of N-linked glycoprotein high mannose glycans, together with the corresponding oligosaccharides containing a central glucose unit, were synthesised and tested as glycosyl donors for glycosylation of a GlcNAcAsn glycosyl amino acid catalysed by the endohexosaminidases M (Endo M), A (Endo A) and H (Endo H). Whilst Endo H did not catalyse any glycosylation reactions, both Endo M and Endo A efficiently catalysed glycosylations that were not limited to donors containing the Manbeta(1-->4)GlcNAc linkage. Precise structure activity relationships and time course studies have revealed fine-tuning of the efficiency of the synthetic processes which correlated both with the enzyme used and the precise oxazoline structure. Efficient irreversible glycosylation was achievable with both Endo M and Endo A, further demonstrating the use of structurally modified oxazoline donors as transition state mimics in order to promote enzyme-catalysed synthesis, whilst precluding product hydrolysis; enzymes in these cases display "glycoligase" activity. 相似文献
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A structural failure problem was solved using an integrated and iterative program of testing and analysis. The steps taken in solving the problem were: analytical calculations; operational testing; qualifications of analytical results; problem identification; design of corrective action; and confirmatory testing. 相似文献
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We have performed extensive small-angle neutron scattering (SANS) diffraction studies of the vortex lattice in single crystal
YNi2B2C for B‖c. High-resolution SANS, combined with a field-oscillation vortex lattice preparation technique, allows us to separate Bragg
scattered intensities from two orthogonal domains and accurately determine the unit cell angle, β. The data suggest that upon increasing field there is a finite transition width where both low- and high-field distorted
hexagonal vortex lattice phases, mutually rotated by 45°, coexist. The smooth variation of diffracted intensity from each
phase through the transition corresponds to a redistribution of populations between the two types of domains. 相似文献
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