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71.
Irina Cotiuga Francesco Picchioni Uday S. Agarwal Bastiaan B. P. Staal Jef A. J. M. Vekemans Piet J. Lemstra 《Macromolecular rapid communications》2006,27(4):242-246
Summary: We report the synthesis of well‐defined block copolymers by covalent coupling of hydroxy end‐functionalized polymers. Using the high volatility of the coupling agent phosgene as compared to the solvent, very high conversion (up to 96%) is obtained in a one‐pot reaction with as little as 10−5 moles of each of the reacting polymers, even without prior purification of the as‐received reagents. This has potential as an alternative to the currently practiced method of sequential living polymerization of constituent monomers, with the added advantage of direct knowledge and control over the length distribution of each block.
72.
Age K. Smilde Piet Hein van der Graaf Durk A. Doornbos Ton Steerneman Anita Sleurink 《Analytica chimica acta》1990
When retention measurements are available for a set of solutes on different stationary phases, with varying mobile phase compositions, the resulting data set can be represented by a three-way array. Models that describe the systematic variation in this training set sufficiently, can be used to calibrate a new stationary phase. Two models are tested for this purpose: three-way partial least squares and parallel factor analysis. 相似文献
73.
Synthesis of enantiomeric-pure cyclohexenyl nucleoside building blocks for oligonucleotide synthesis
Lipases were used for the resolution of (±) (4aR, 7R, 8aS)-2-phenyl-4a,7,8,8a-tetrahydro-4H-1,3-benzodioxine. This separation was carried out on preparative scale and used for the synthesis of eight phosphoramidites of cyclohexenyl nucleosides (d- and l-series). 相似文献
74.
Pascal Röthlisberger Fabienne Levi-Acobas Ivo Sarac Rémy Ricoux Jean-Pierre Mahy Piet Herdewijn Philippe Marlière Marcel Hollenstein 《Tetrahedron letters》2018,59(48):4241-4244
Abasic sites are amongst the most frequent DNA lesions and result from spontaneous hydrolysis of the glycosidic bond or from the removal of damaged nucleobases. These depurination events can also occur on free deoxyribonucleoside triphosphates present in cells and lead to the formation of an abasic site triphosphate of which very little is known. Herein, we report the synthesis and biochemical characterization of the minimal triphosphate dФTP. Unexpectedly, dФTP is tolerated by various DNA polymerases and the incorporation efficiency obeys the A-rule. Single incorporation of dФMP units were also observed opposite abasic sites and the addition of prosthetic molecules mimicking base-pairs do not seem to favor the process. 相似文献
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78.
Sander S. van Berkel Jan Willem Terpstra Piet W.N.M. van Leeuwen 《Tetrahedron letters》2004,45(41):7659-7662
The coupling of arylboronic acids with imidazole in the presence of binuclear bis-μ-hydroxy copper(II) complexes is reported. The reactions can be performed in air as well as under nitrogen atmosphere. Reactions are carried out at ambient temperature without the need for base. The presence of water is essential for the reaction to proceed. Ligand effects on the yield and selectivity are reported. 相似文献
79.
Daniel Alpay Piet Bruinsma Aad Dijksma Henk de Snoo 《Integral Equations and Operator Theory》1992,15(3):378-388
By an oversight on the part of the authors this section was not included in the paper previously published in Integral Equations Operator Theory, volume 14/4 (1991), 466–500.
Present address:Department of Mathematics Ben-Gurion University of the Negev Beersheva Israel 相似文献
80.
An assessment of the practical implementation of several spectroscopic analysis methods in the analytical service department of the reserach laboratory of a large electronic industry is provided. The emphasis is on inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The evolution of these methods in the department in recent years and their present position in the light of the analysis requests is introductory discussed. A preview assessment of the methods in terms of their strong and weak points then forms the basis for a subsequent discussion in which representative examples are used to illustrate in detail why in a particular situation a particular method is applied as the preferred one. It is concluded that ICP-AES is the most rugged and flexible, and therefore the most often applied method, while ICP-MS is uniquely suitable for ultra-trace and survey analysis of solutions and LA-ICP-MS is uniquely suitable for direct solids and local analysis. The ultimate conclusion is that neither of the three methods alone can answer all the analytical questions: they supplement and complement each other, and may even require supplementation by classical analytical methods. 相似文献