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101.
Viktorie Štísová Stephane Goffinont Melanie Spotheim-Maurizot Marie Davídková 《Radiation Physics and Chemistry》2010,79(8):880-889
Signaling by estrogens, risk factors in breast cancer, is mediated through their binding to the estrogen receptor protein (ER), followed by the formation of a complex between ER and a DNA sequence, called estrogen response element (ERE). Anti-estrogens act as competitive inhibitors by blocking the signal transduction. We have studied in vitro the radiosensitivity of the complex between ERα, a subtype of this receptor, and a DNA fragment bearing ERE, as well as the influence of an estrogen (estradiol) or an anti-estrogen (tamoxifen) on this radiosensitivity. We observe that the complex is destabilized upon irradiation with γ rays in aerated aqueous solution. The analysis of the decrease of binding abilities of the two partners shows that destabilization is mainly due to the damage to the protein. The destabilization is reduced when irradiating in presence of tamoxifen and is increased in presence of estradiol. These effects are due to opposite influences of the ligands on the loss of binding ability of ER. The mechanism that can account for our results is: binding of estradiol or tamoxifen induces distinct structural changes of the ER ligand-binding domain that can trigger (by allostery) distinct structural changes of the ER DNA-binding domains and thus, can differently affect ER-ERE interaction. 相似文献
102.
103.
Hoen R Leleu S Botman PN Appelman VA Feringa BL Hiemstra H Minnaard AJ van Maarseveen JH 《Organic & biomolecular chemistry》2006,4(4):613-615
A BICOL derived monodentate phosphoramidite ligand gives ee's up to 89% in the enantioselective Rh-catalysed hydrogenation of N-acyl dehydroalanine using water as the solvent. 相似文献
104.
105.
106.
107.
Bartosz Zarychta Jacek Zaleski Andrzej Sporzyski Marek Dbrowski Janusz Serwatowski 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(5):o344-o345
The molecule of the title compound, C7H7BO3, is planar, and the bond lengths and angles are typical. The formyl group is essentially coplanar with the benzene ring but does not influence significantly the distortion of the ring, although the formyl group does have a strong influence on the crystal packing. The geometry of the boronic acid group is typical. In the crystal structure, the molecules are linked by O—H⋯O hydrogen bonds. 相似文献
108.
Moutard S Djedaïni-Pilard F Meudal S Luijten W Perly B Pilard S 《Rapid communications in mass spectrometry : RCM》2003,17(22):2535-2540
In the continuing challenge to increase the performance of cyclodextrins (CDs) for various applications, new phospholipidyl-cyclodextrin derivatives showing improved self-organization properties in water have been synthesized, as new carriers for drug vectorization, starting from natural beta-cyclodextrin. Due to the important chemical modifications of the original cyclic oligosaccharide molecules, simple nuclear magnetic resonance (NMR) experiments do not easily lead to both an unambiguous assignment of the structures and to a rapid evaluation of the purity of the final products. However, positive and negative ion electrospray ionization (ESI-MS) in combination with accurate mass measurements and tandem mass spectrometry (MS/MS) led to the positive structural identification of the first series of these new amphiphilic compounds. 相似文献
109.
Stephane Jaffard Robert M. Young 《Proceedings of the American Mathematical Society》1998,126(2):553-560
A sequence of vectors in a separable Hilbert space is said to be a Schauder basis for if every element has a unique norm-convergent expansion
If, in addition, there exist positive constants and such that
then we call a Riesz basis. In the first half of this paper, we show that every Schauder basis for can be obtained from an orthonormal basis by means of a (possibly unbounded) one-to-one positive self adjoint operator. In the second half, we use this result to extend and clarify a remarkable theorem due to Duffin and Eachus characterizing the class of Riesz bases in Hilbert space.
110.
V. N. Duginov V. G. Grebinnik R. Horyn B. F. Kirillov J. Klamut I. A. Krivosheev T. N. Mamedov V. G. Olshevsky A. V. Pirogov V. Yu. Pomjakushin A. N. Ponomarev A. J. Zaleski V. A. Zhukov 《Hyperfine Interactions》1994,85(1):311-316
Zero field muon spin rotation and magnetic susceptibility experiments on investigation of magnetic properties of cuprateY
2Cu2O5 have been performed in the temperature range 4.2–30 K. Transverse fieldSR-experiments have been also carried out in order to obtain accurate information about transition temperature and to study the influence of the external magnetic field. Our data show that two magnetic phase transitions occur inY
2Cu2O5 with lowering temperature. Upper Neel temperatureT
N=13 K is consistent with previous experimental data. We obtained the temperature dependence of the local magnetic field on the muonB
(T) in the antiferromagnetic phase.B
(T) reveals a peculiarity (some change of the slope) near the temperatureT
N=7.5 K, which can be interpreted as an additional magnetic phase transition caused by a change in magnetic ordering of the copper subsystem. Applying a small external magnetic field 50 Oe leads to smearing of the peculiarity inB
(T) dependence. 相似文献