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151.
The construction of a new type of enzyme electrode for the potentiometric determination of glucose is reported. The electrode response is based on the enzymecatalyzed reactions: The highly selective iodide sensor monitors the local decrease in the iodide activity at the electrode surface. The properties of the above reactions were examined kinetically, with flow-stream techniques and potentiometric detection. The glucose electrode constructed and the use of flow-stream experiments with two iodide sensors provided accurate and convenient glucose determinations in the absence of some oxidizing and reducing agents. 相似文献
152.
153.
H. De Kerret E. Nagy R.S. Orr M. Regler W. Schmidt-Parzefall K. Winter A. Brandt H. Dibon G. Flügge F. Niebergall P.E. Schumacher K.R. Schubert J.J. Aubert C. Broll G. Coignet J. Favier L. Massonnet M. Vivargent G. Neuhofer 《Physics letters. [Part B]》1977,69(3):372-376
We report on a study of the charge-exchange reaction pp → nΔ++(1232) at the CERN intersecting storage rings (ISR) in the energy range √s = 23 to 53 GeV. From our analysis of the energy dependence of the total cross-section, of the differential cross-section dσ/dt and of the decay angular distributions we find evidence that pion exchange is dominant up to √s = 23 GeV and that (?+A2) exchange dominates the reaction for √s ? 30 GeV, as described by simple Regge-pole models. 相似文献
154.
Both lines of the Mössbauer quadrupole doublet of FECO3 reveal the same temperature dependence, thus their narrowing with increasing temperature cannot be explained by magnetic relaxation. The width of the σ line is markedly increased by oxidation even at about 570 K. To explain the anomalous temperature dependence of the linewidth a possible model, based on random transitions between two or more states of the iron nucleus surrounding producing different EFG, is proposed. 相似文献
155.
Summary The geodesic graph of Riemannian spaces all geodesics of which are orbits of 1-parameter isometry groups was constructed by
J. Szenthe in 1976 and it became a basic tool for studying such spaces, called g.o.\ spaces. This infinitesimal structure
corresponds to the reductive complement <InlineEquation ID=IE"1"><EquationSource Format="TEX"><![CDATA[<InlineEquation ID=IE"2"><EquationSource
Format="TEX"><![CDATA[$]]></EquationSource></InlineEquation>]]></EquationSource></InlineEquation>\mathfrak m$ in the case
of naturally reductive spaces. The systematic study of Riemannian g.o. spaces was started by O. Kowalski and L.~Vanhecke in
1991, when they introduced the most important definitions, classified the low-dimensional examples and described the basic
constructions of this theory. The aim of this paper is to investigate a connection theoretical analogue of the concept of
the geodesic graph. 相似文献
156.
Symmetry breaking solutions of several model theories are investigated with the result that constant gauge transformations of the fields describing zero mass Goldstone particles are responsible for the formal possibility of the spontaneous symmetry breaking.
相似文献157.
I. Zay A. Vértes G. Takácsi Nagy M. Suba K. Burger 《Journal of Radioanalytical and Nuclear Chemistry》1985,88(2):343-350
Iron injections containing high spin iron(III) complexes may undergo a reductive decomposition during preparation or storage. This process was investigated by the Mössbauer spectroscopy of ice samples prepared by quick-freezing of the injection. The comparison of three model compounds and the correlation between the osmotic pressure of the solutions and their iron(II) concentration formed in the decomposition process and determined by Mössbauer measurements revealed the reason and mechanism of the decomposition. 相似文献
158.
D. L. Nagy R. Doerfler B. Molnár G. Ritter J. Waigel N. Zeman 《Hyperfine Interactions》1983,16(1-4):1051-1055
The Fe3+ fraction after the EC of57Co is usually evaluated supposing that ferric ions contribute a quadrupole doublet to Mössbauer emission spectra. It is shown that a not sufficiently fast relaxation of the electron spins may falsify the evaluated intensity even by a factor 2. Additional information can be gained from measurements performed in a large velocity span at low temperatures in high magnetic fields. 相似文献
159.
Varga L Nagy T Dorman G Kalman F Urge L Darvas F 《Journal of combinatorial chemistry》2006,8(3):338-343
We present here the discovery of a novel, versatile, multicomponent reaction leading to various 4-[4-(pyridinium-1-yl)-2,5-dioxo-2,5-dihydro-1H-pyrrol-3-yl]-2H-pyrazol-3-olate inner salts. The structure of the unusual zwitterionic inner salts was elucidated, and the scope of the novel reaction was investigated. After rapid optimization, the reaction was adapted to parallel synthesis, and an 800-membered compound library was produced. 相似文献
160.
A practical, efficient and scalable formal total synthesis of (rac)- and (S)-camptothecin is described, which proceeds via the known DE ring building blocks 19 and (S)-19, respectively. The racemic synthesis starts from diethyl oxalate and uses straightforward carbonyl chemistry in order to generate the pyridone ring system. 19 was formed in 8.4% overall yield over 9 linear steps avoiding any chromatographic purification. The asymmetric version of this approach encompassed a diastereoselective Grignard addition to the enantiomerically pure alpha-ketoester 30 in order to generate the (S)-configured quaternary stereocenter. The auxiliary could be recycled in high yield and was successfully reused multiple times. The final steps paralleled the racemic approach. (S)-19 was thus prepared in 9.4% overall yield (er = 95 : 5) over 10 steps. 相似文献