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排序方式: 共有1445条查询结果,搜索用时 15 毫秒
1.
Dr. Sebastian Lars Müller Xinglong Zhou Dr. Peter Leonard Oxana Korzhenko Dr. Constantin Daniliuc Prof. Dr. Frank Seela 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(12):3077-3090
Silver-mediated α-dC–Ag+–β-dC hybrid base pairs decorated with 5-iodo- or 5-octadiynyl residues are well accommodated in duplex DNA. A strong Tm increase and favorable thermodynamic data for duplex DNA were observed after addition of silver ions. The phenomenon is particularly obvious when both nucleobases of the base pairs are functionalized. Neither the position of the base pair, nor the type of 5-substituent had a negative influence. On the contrary, functionalization of conventional silver-mediated β-dC–Ag+–β-dC homo base pairs showed a negative impact induced by the bulky substituents. To this end, cytosine modified 12-mer oligodeoxynucleotides were prepared by solid-phase synthesis employing new α-anomeric 2′-deoxycytidine phosphoramidites. A multigram scale synthesis was developed for 5-iodo-α-d -2′-deoxycytidine ( 1 ) employing the direct glycosylation of cytosine with Hoffer's α-d -halogenose followed by separation of anomeric DMT nucleosides. Regarding base-pair stability and functionalization silver-mediated α/β-dC hybrid base pairs were found to be superior to β/β-dC homo pairs. According to their extraordinary properties, they might find applications in DNA diagnostics, material science, or nanotechnology. 相似文献
2.
Leonard P. Kinnicutt 《Fresenius' Journal of Analytical Chemistry》1883,22(1):257-258
Ohne Zusammenfassung 相似文献
3.
A. G. Green S. Rideal Leonard P. Kinnicutt und John U. Nef 《Fresenius' Journal of Analytical Chemistry》1886,25(1):222-223
Ohne Zusammenfassung 相似文献
4.
Leonard M Khalilov Ludmila V Parfenova Askhat G Ibragimov Usein M Dzhemilev 《Journal of organometallic chemistry》2004,689(2):444-453
This paper is dedicated to a study of properties of the following novel optically active organoaluminium compounds (OACs): (1S,2S)-l,7,7-trimethyl-2-[(dialkylalumina)oxy]-bicyclo[2.2.1]heptanes and (1S)-N-(dialkylalumina)-6,7-dimethoxy-1-methyl-1,2,3,4- tetrahydroisoquinolines. The synthesis of the chiral OACs was carried out in the reaction of either natural camphor or salsolidine with both AlEt3 and i-Bu2AlH. The main goal of the research was to investigate the stereodifferentiating activity of the chiral OACs in the olefin carbo- and cycloalumination reactions, catalyzed by Cp2ZrCl2. 相似文献
5.
Miklos Ajtai James Aspnes Moni Naor Yuval Rabani Leonard J Schulman Orli Waarts 《Journal of Algorithms in Cognition, Informatics and Logic》1998,29(2):306-357
On-line machine scheduling has been studied extensively, but the fundamental issue of fairness in scheduling is still mostly open. In this paper we explore the issue in settings where there are long-lived processes which should be repeatedly scheduled for various tasks throughout the lifetime of a system. For any such instance we develop a notion ofdesiredload of a process, which is a function of the tasks it participates in. Theunfairnessof a system is the maximum, taken over all processes, of the difference between the desired load and the actual load.An example of such a setting is thecarpool problemsuggested by Fagin and Williams [IBM Journal of Research and Development27(2) (1983), 133–139]. In this problem, a set ofnpeople form a carpool. On each day a subset of the people arrive and one of them is designated as the driver. A scheduling rule is required so that the driver will be determined in a “fair” way.We investigate this problem under various assumptions on the input distribution. We also show that the carpool problems can capture several other problems of fairness in scheduling. 相似文献
6.
Leonard J. Prins 《Tetrahedron letters》2006,47(16):2735-2738
An efficient synthesis of ortho-substituted triphenolamines via reductive amination is reported. This approach allows access to this increasingly important class of ligands in a structurally systematic way using either commercially or easily synthesizable building blocks. 相似文献
7.
A novel two-dimensional coordination polymer containing infinite, coherently pitched single and triple helical motifs is formed by the self-assembly of Cd2+, succinate, water and a bipyridyl ligand. 相似文献
8.
Kaale E Leonard S Van Schepdael A Roets E Hoogmartens J 《Journal of chromatography. A》2000,895(1-2):67-79
A selective, sensitive, and rapid pre-capillary derivatization method for determination of the multicomponent aminoglycoside antibiotic gentamicin is described. The derivatization reagents 1,2-phthalic dicarboxaldehyde and mercaptoacetic acid were used and the thioisoindole derivative was UV detected at 330 nm. A central composite experimental design was performed to optimize selectivity and derivatization conditions. Baseline separation of gentamicin C1, C1a, C2, C2a, C2b, sisomicin and several minor components was achieved with a background electrolyte containing 30 mM sodium tetraborate, 7.5 mM beta-cyclodextrin and 12.5% (v/v) methanol at pH 10. Quantitative analysis was performed and illustrated the potential use of capillary electrophoresis for the identification and quantitation of gentamicin as an alternative to methods prescribed in the United States Pharmacopeia and European Pharmacopoeia. 相似文献
9.
10.
Leonard S Van Schepdael A Iványi T Lázár I Rosier J Vanstockem M Vermeersch H Hoogmartens J 《Electrophoresis》2005,26(3):627-632
A capillary electrophoretic (CE) method was developed for the separation of diastereoisomers of a new human immunodeficiency virus (HIV) protease inhibitor TMC114. In total 16 isomers of this drug have been synthesized (eight pairs of enantiomers). We succeeded in the separation of the eight diastereoisomers, but no enantiomers could be separated. Because of the high similarity and water-insolubility of these isomers, the separation is a real challenge. Different CE modes were tried out: capillary zone electrophoresis (CZE), nonaqueous capillary electrophoresis (NACE), micellar electrokinetic capillary chromatography (MEKC), and microemulsion electrokinetic capillary chromatography (MEEKC). Only MEEKC offered resolution of these compounds. 相似文献