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91.
Orsolya Csernák ágnes Buvári-barcza János Samu Lajos Barcza 《Journal of inclusion phenomena and macrocyclic chemistry》2005,51(1):59-63
A relatively high and unexpected increase of inclusion complex stabilities could be detected in some half dissociated dicarboxylic acids (HA− ions) with intramolecular H-bonding. The intermolecular hydrogen bonds between the protruding functional groups of the guest and the hydroxy groups of the host are known to enhance the stability of the cyclodextrin (CD) inclusion complexes. The enhanced inclusion of HA− species is promoted, not by the intermolecular but by the intramolecular H-bond indirectly, resulting in a compact shape of the guest with more favourable space filling. 相似文献
92.
Lajos Fodor János Szabó Erzsébet Szúcs Gábor Bernáth Pál Sohár József Tamás 《Tetrahedron》1984,40(20):4089-4095
6,7-Dialkoxy-2-aryl-41-1,3-benzothiazines (1a?) react with chloroacetyl chlorlde to give condensed β-lactam derivatives (2a?). Basic treatment of 2a? in methanol led to the corresponding 1,4-banzothiazepine derivativee (3a?) ring expansion. The structures of the products were determined by IR, NMR and MS studies 相似文献
93.
N9- and N7-substituted (guaninyl)acetic esters were studied by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in order to determine their ratio in alkylation reactions. The loss of ammonia is significantly different for the N9- and N7-alkylated guanine regioisomer pairs. More importantly, the abundance of the [MH-17]+ ion is in linear correlation with the N9-isomer content. Therefore, the ratio of regioisomers can be determined in a mixture containing these compounds. 相似文献
94.
Lajos Papp 《Mikrochimica acta》1978,69(3-4):375-381
Zusammenfassung Für die spektrographische und spektrometrische Bestimmung nicht leitender Stoffe wurde ein Elektrodensystem mit Kunststoffbindung entwickelt. In einem Konzentrationsbereich von 0,01–1,0% ließ sich damit der relative Fehler von 4–15% auf 0,5–4,0% herabsetzen. Die Selbstabsorption wird in erheblichem Ausmaß zurückgedrängt; demzufolge werden die Eichkurven in einem größeren Konzentrationsbereich linear.
A method of emission spectrum analysis for determining the trace element content in small amounts of powder and solutions
Summary An electrode system with plastic binding was developed for spectrographic and spectrometric determination of non-conducting substances. In a concentration range of 0.01–1.0%, the relative error of 4–15% could thereby be reduced to 0.5–4.0%. The autoabsorption is suppressed to an appreciable extent; in consequence, the calibration curves become linear in a larger concentration range.相似文献
95.
Marjaneh Jafari Fesharaki Gholam Reza Nabiyouni Júlia Dégi Lajos Pogány ádám Révész Imre Bakonyi László Péter 《Journal of Solid State Electrochemistry》2012,16(2):715-722
Codeposition of Ru and Co was studied at room temperature and at 50 °C with various Ru3+ and Co2+ concentrations in the electrolyte. The codeposition of Co and Ru proved to be anomalous since no pure Ru could be obtained
in the presence of Co2+ in the electrolyte, but a significant Co incorporation into the deposit was detected at potentials where the deposition of
pure Co was not possible. The composition of the deposits varied monotonously with the change of the concentration ratio of
Co2+ and Ru3+. The deposition of Ru was much hindered, and the current efficiency was a few percent only when the molar fraction of Co
in the deposit was low. Continuous deposits could be obtained only when the molar fraction of Co in the deposit was at least
40 at.%. The deposit morphology was related to the molar fraction of Co in the deposit. The X-ray diffractograms are in conformity
with a hexagonal close-packed alloy and indicate the formation of nanocrystalline deposits. Two-pulse plating did not lead
to a multilayer but to a Co-rich alloy. Magnetoresistance of the samples decreased with increasing Ru content. 相似文献
96.
The ring transformations of dichloro-β-lactam-fused 2-aryl-1,3-benzothiazines with sodium methoxide were investigated. With 2 equiv of base, the dichloro-β-lactam derivatives underwent rearrangement and dihydro-1,4-benzothiazepines, 3,4-substituted isoquinolines and substituted thiazole disulfides were isolated. A possible reaction mechanism is proposed for the simultaneous formation of the novel products. The formation of isoquinoline and thiazole derivatives can be explained by sulfur extrusion and addition sequences. 相似文献
97.
Our aim is to investigate spaces with σ-discrete and meager dense sets, as well as selective versions of these properties. We construct numerous examples to point out the differences between these classes while answering questions of Tkachuk [22], Hutchison [13] and the authors of [7]. 相似文献
98.
Eszter Hazai Istvan Hazai Laszlo Demko Sandor Kovacs David Malik Peter Akli Peter Hari Julianna Szeman Eva Fenyvesi Edina Benes Lajos Szente Zsolt Bikadi 《Journal of computer-aided molecular design》2010,24(8):713-717
Cyclodextrins are cyclic oligosaccharides that are able to form water-soluble inclusion complexes with small molecules. Because of their complexing ability, they are widely applied in food, pharmaceutical and chemical industries. In this paper we describe the development of a free web-service, Cyclodextrin KnowledgeBase: (http://www.cyclodextrin.net). The database contains four modules: the Publication, Interaction, Chirality and Analysis Modules. In the Publication Module, almost 50,000 publication details are collected that can be retrieved by text search. In the Interaction and Chirality Modules relevant literature data on cyclodextrin complexation and chiral recognition are collected that can be retrieved by both text and structural searches. Moreover, in the Analysis Module, the geometries of small molecule-cyclodextrin complexes can be predicted using molecular docking tools in order to explore the structures and interaction energies of the inclusion complexes. Complex geometry prediction is made possible by the built-in database of 95 cyclodextrin derivatives, where the 3D structures as well as the partial charges are calculated and stored for further utilization. The use of the database is demonstrated by several examples. 相似文献
99.
JPC – Journal of Planar Chromatography – Modern TLC - Thin-layer chromatography with microbiological detection (direct bioautography) of amphotericin B. has never been reported. The... 相似文献
100.
Recent finiteness results concerning the lengths of arithmetic progressions in linear combinations of elements from finitely
generated multiplicative groups have found applications to a variety of problems in number theory. In the present paper, we
significantly refine the existing arguments and give an explicit upper bound on the length of such progressions. 相似文献