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81.
Glòria Sanclimens Laia CrespoMiquel Pons Ernest Giralt Fernando Albericio Miriam Royo 《Tetrahedron letters》2003,44(9):1751-1754
Although the solid-phase mode is an excellent strategy for the preparation of both biomolecules and small molecules, the synthesis of polyproline-based dendrimers has provided evidence that the capacity of the bead is limited. This phenomenon, which can be interpreted as saturation or stress of the resin, can lead to a complete breakdown of the bead structure. 相似文献
82.
Eric RaponiJean-Marc Pons 《Tetrahedron letters》2003,44(51):9193-9196
Silylketenes react under Kulinkovich conditions through two competitive pathways: alkene/ketene exchange versus nucleophilic addition. In both cases, the organotitanium intermediate reacts with an aldehyde to yield an adduct which can undergo an elimination to yield a vinylcyclopropanol or an α,β-unsaturated carbonyl compound. 相似文献
83.
Sp. Pantelakis An. Kyrsanidi E. El-Magd J. Dünnwald Y. Barbaux G. Pons 《Theoretical and Applied Fracture Mechanics》1999,31(1):1513
Characterization of the creep resistance of 30 newly developed aluminium alloys is made for structural applications of the next generation Supersonic Civil Transport Aircafts (SCT). These materials refer to the 2xxx, 6xxx and 8xxx aluminium alloy series. Creep behaviour is ranked to the usability and applicability of the alloys according to performance. A procedure is developed for validating the criteria of extrapolating creep data. 相似文献
84.
85.
DNA analysis using variable temperature technologies such as melting curve analysis, high temperature mutant discrimination or immobilised PCR relies upon the use of immobilised probes that need to be stable over a wide temperature range. In this work a comparison of the thermal stability of gold surfaces modified with alkanethiol and diazonium salt derived layers is presented. Electrochemical impedance spectroscopy and cyclic voltammetry were used to characterize the electrode arrays. The applicability of the surfaces for DNA sensing was demonstrated following the thermal treatment, with the diazonium-modified surface being markedly more stable. 相似文献
86.
Denney MC Pons V Hebden TJ Heinekey DM Goldberg KI 《Journal of the American Chemical Society》2006,128(37):12048-12049
In the presence of an iridium pincer complex, dehydrogenation of ammonia borane (H3NBH3) occurs rapidly at room temperature in tetrahydrofuran to generate 1.0 equivalent of H2 and [NH2BH2]5. A metal borohydride complex has been isolated as a dormant form of the catalyst which can be reactivated by reaction with H2. 相似文献
87.
Fraley AW Pons B Dalkara D Nullans G Behr JP Zuber G 《Journal of the American Chemical Society》2006,128(33):10763-10771
Oligonucleotide delivery is a crucial issue for therapeutical purposes and is often addressed by conjugation to short cationic peptides although with controversial results. To further examine this mechanism, a 15-mer anionic oligonucleotide was conjugated to a cationic peptide in order to obtain a diblock compound with an overall positive charge with aggregation properties. These microaggregates were efficiently internalized in cells via the expeditious pathway used by commercial gene delivery systems. Moreover, stability of the duplex formed with the complementary sequence increased without inhibiting oligonucleotide enzyme recognition as shown by the properties of the conjugate to prime chain elongation by Taq DNA polymerase in a linear amplification/sequencing process. 相似文献
88.
Pons T Medintz IL Wang X English DS Mattoussi H 《Journal of the American Chemical Society》2006,128(47):15324-15331
We present a single particle fluorescence resonance energy transfer (spFRET) study of freely diffusing self-assembled quantum dot (QD) bioconjugate sensors, composed of CdSe-ZnS core-shell QD donors surrounded by dye-labeled protein acceptors. We first show that there is direct correlation between single particle and ensemble FRET measurements in terms of derived FRET efficiencies and donor-acceptor separation distances. We also find that, in addition to increased sensitivity, spFRET provides information about FRET efficiency distributions which can be used to resolve distinct sensor subpopulations. We use this capacity to gain information about the distribution in the valence of self-assembled QD-protein conjugates and show that this distribution follows Poisson statistics. We then apply spFRET to characterize heterogeneity in single sensor interactions with the substrate/target and show that such heterogeneity varies with the target concentration. The binding constant derived from spFRET is consistent with ensemble measurements. 相似文献
89.
Pedro A. Valiente Alejandro Gil L. Paulo R. Batista Ernesto R. Caffarena Tirso Pons Pedro G Pascutti 《Journal of computational chemistry》2010,31(15):2723-2734
The standard parameterization of the Linear Interaction Energy (LIE) method has been applied with quite good results to reproduce the experimental absolute binding free energies for several protein–ligand systems. However, we found that this parameterization failed to reproduce the experimental binding free energy of Plasmepsin II (PlmII) in complexes with inhibitors belonging to four dissimilar scaffolds. To overcome this fact, we developed three approaches of LIE, which combine systematic approaches to predict the inhibitor‐specific values of α, β, and γ parameters, to gauge their ability to calculate the absolute binding free energies for these PlmII‐Inhibitor complexes. Specifically: (i) we modified the linear relationship between the weighted nonpolar desolvation ratio (WNDR) and the α parameter, by introducing two models of the β parameter determined by the free energy perturbation (FEP) method in the absence of the constant term γ, and (ii) we developed a new parameterization model to investigate the linear correlation between WNDR and the correction term γ. Using these parameterizations, we were able to reproduce the experimental binding free energy from these systems with mean absolute errors lower than 1.5 kcal/mol. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010 相似文献
90.
Fernanda M. Ribeiro Laia Ana Matos Beja Teresa M.V.D. Pinho e Melo 《Tetrahedron》2010,66(46):8815-8822
The reactivity of buta-2,3-dienoates towards aziridines is reported. Typically, allenoates react as the 2π-component in the [3+2] cycloaddition with azomethine ylides generated from aziridines, affording 4-methylenepyrrolidines in a site-, regio- and stereoselective fashion. However, N-cyclohexyl- or N-tert-butyl-2-benzoyl-3-phenylaziridines showed a different reactivity in the reaction with buta-2,3-dienoates. Pyrrole derivatives were obtained as single or major products resulting from a formal [3+2] cycloaddition via C-N bond cleavage of the three-membered ring heterocycle leading to functionalized pyrroles. From the reaction with allenoates bearing bulkier C-4 substituents 4-methylenepyrrolidines were also formed as minor products. 相似文献