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21.
Marat Gafurov Vasyl Denysenkov Mark J. Prandolini Thomas F. Prisner 《Applied magnetic resonance》2012,43(1-2):119-128
The temperature dependence of the water-proton dynamic nuclear polarization (DNP) enhancement from Fremy’s salt nitroxide radicals was measured in a magnetic field of 9.2?T (corresponding to 260?GHz microwave (MW) and 392?MHz NMR frequencies) in the temperature range of 15–65?°C. The temperature could be determined directly from the proton NMR line shift of the sample. Very high DNP enhancements of ?38 (signal integral) or ?81 (peak intensity) could be achieved with a high-power gyrotron MW source. The experimental findings are compared with classical Overhauser theory for liquids, which is based on the translational and rotational motion of the molecules and with molecular dynamics calculations of the coupling factor. 相似文献
22.
Pivovarenko VG Zamotaiev OM Shvadchak VV Postupalenko VY Klymchenko AS Mély Y 《The journal of physical chemistry. A》2012,116(12):3103-3109
By using four labels of the 3-hydroxyflavone family displaying selective sensitivity to hydrogen bond (HB) donors and poor response to other polar molecules, we developed an approach for measuring local water concentration [H(2)O](L) (or partial volume of water: W(A) = [H(2)O](L)/55.6) in the label surrounding both in solvent mixtures and in biomolecules by the intensity ratio of two emissive forms of the label, N*/T*. Using a series of binary water/solvent mixtures with limited preferential solvation effects, a linear dependence of log(N*/T*) on the local concentration of HB donor was obtained and then used as a calibration curve for estimating the W(A) values in the surroundings of the probes conjugated to biomolecules. By this approach, we estimated the hydration of the labels in different peptides and their complexes with DNAs. We found that W(A) values for the label at the peptide N-terminus are lower (0.63-0.91) than for free labels and depend strongly on the nature of the N-terminal amino acid. When complexed with different DNAs, the estimated hydration of the labels conjugated to the labeled peptides was much lower (W(A) = 0-0.47) and depended on the DNA nature and linker-label structure. Thus, the elaborated method allows a site-specific evaluation of hydration at the surface of a biomolecule through the determination of the partial volume of water. We believe the developed procedure can be successfully applied for monitoring hydration at the surface of any biomolecule or nanostructure. 相似文献
23.
The indides Eu2Pd2In and Eu2Pt2In were synthesized from the elements in sealed tantalum tubes in an induction furnace. The samples were characterized by powder X‐ray diffraction. The structures were refined on the basis of single‐crystal X‐ray diffractometer data: HT‐Pr2Co2Al type, C2/c, a = 1035.7(2), b = 592.9(1), c = 823.6(2) pm, β = 104.26(1) °, wR2 = 0.026, 1075 F2 values, 25 variables for Eu2Pd2In and a = 1017.2(2), b = 588.7(1), c = 826.5(1) pm, β = 103.76(1) °, wR2 = 0.062, 706 F2 values, 25 variables for Eu2Pt2In. The indium atoms have four platinum (palladium) neighbors in strongly distorted tetrahedral coordination at Pt–In and Pd–In distances ranging from 273 to 275 pm. These InPd4/2 and InPt4/2 units are condensed via common edges to infinite InPd2 and InPt2 chains, which are surrounded by the europium atoms. The chains form the motif of hexagonal rod packing. 相似文献
24.
Vasyl I. Zaremba Ihor R. Muts Yaroslav M. Kalychak Rolf-Dieter Hoffmann Rainer Pttgen 《Journal of solid state chemistry》2001,160(2):415
The title compound was synthesized by reacting the elements in an arc-melting apparatus under purified argon and subsequent annealing at 870 K. Ca3Ni8In4 was investigated using X-ray diffraction on both powders and single crystals: P63mc, a=898.9(1) pm, c=752.2(2) pm, wR2=0.0591, 327 F2 values, and 35 parameters. This structure is an ordered, noncentrosymmetric variant of the BaLi4 type. The nickel and indium atoms build a complex three-dimensional [Ni8In4] polyanion in which the calcium atoms fill distorted hexagonal channels. To a first approximation the formula may be written as (3 Ca2+)6+ [Ni8In4]6−. Within the polyanion the Ni1, Ni3, and Ni4 atoms form one-dimensional cluster units which extend in the c direction while the Ni2 atoms have only indium neighbors in a distorted tetrahedral coordination. The Ni–Ni distances in the cluster range from 241 to 266 pm. The cluster units are surrounded and interconnected by indium atoms. The group– subgroup relation from centrosymmetric BaLi4 to noncentrosymmetric Ca3Ni8In4 is presented. Chemical bonding in Ca3Ni8In4 and the structural relation with Lu3Co7.77Sn4, Ca3Au6.61Ga4.39, and Co2Al5 is briefly discussed. 相似文献
25.
Dr. Liliyana Zaayter Dr. Mattia Mori Tanveer Ahmad Dr. Waseem Ashraf Dr. Christian Boudier Dr. Vasyl Kilin Dr. Krishna Gavvala Dr. Ludovic Richert Dr. Sylvia Eiler Dr. Marc Ruff Dr. Maurizio Botta Dr. Christian Bronner Dr. Marc Mousli Prof. Yves Mély 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(58):13363-13375
During DNA replication, ubiquitin-like, containing PHD and RING fingers domains 1 (UHRF1) plays key roles in the inheritance of methylation patterns to daughter strands by recognizing through its SET and RING-associated domain (SRA) the methylated CpGs and recruiting DNA methyltransferase 1 (DNMT1). Herein, our goal is to identify UHRF1 inhibitors targeting the 5′-methylcytosine (5mC) binding pocket of the SRA domain to prevent the recognition and flipping of 5mC and determine the molecular and cellular consequences of this inhibition. For this, we used a multidisciplinary strategy combining virtual screening and molecular modeling with biophysical assays in solution and cells. We identified an anthraquinone compound able to bind to the 5mC binding pocket and inhibit the base-flipping process in the low micromolar range. We also showed in cells that this hit impaired the UHRF1/DNMT1 interaction and decreased the overall methylation of DNA, highlighting the critical role of base flipping for DNMT1 recruitment and providing the first proof of concept of the druggability of the 5mC binding pocket. The selected anthraquinone appears thus as a key tool to investigate the role of UHRF1 in the inheritance of methylation patterns, as well as a starting point for hit-to-lead optimizations. 相似文献
26.
The work deals with the problem of determination of automobile petrol of various octane numbers and petroleum contamination of some objects on the basis of analysis of photoluminescence spectra of automobile petrol samples. For this purpose steady state luminescence properties of samples of automobile petrol of different types being in sale were measured. Samples of automobile petrol diluted in hexane were prepared and their luminescence spectra were measured at room and liquid nitrogen temperatures of samples. We constructed concentration dependences of luminescence intensity of both wide band luminescence of liquid solutions obtained at room temperature and peak intensities of luminescence lines of quasi linear spectra of solutions frozen at 77 K. Possibility to use luminescence method for analysis of petrol pollutions on some objects is illustrated by results of investigation of pine-wood pieces contaminated by automobile petrol. 相似文献
27.
28.
Dmytro Kharchenko Vasyl Kharchenko Iryna Lysenko 《Central European Journal of Physics》2011,9(3):698-709
We apply the phase field crystal method for nonequilibrium patterning to stochastic systems with an external source in which
transient dynamics is essential. Considering a prototype model for a one-component periodic system subjected to external influence
kind of irradiation we study properties of pattern selection processes and external noise induced pattern-forming transitions.
These processes are examined by means of the structure function dynamics analysis. Nonequilibrium pattern-forming transitions
are analyzed numerically. 相似文献
29.
New methods for the synthesis of complexes of molybdenyl with hydrophobic alkyl-substituted hydroxamic acids have been developed. A number of novel coordination compounds of the general formula MoO2L2 (where HL is decano-, N-methyl-decano-, N-methyl-hexano-, N-methyl-1-adamantano- and N-tert-butyl-hexanohydroxamic acids) have been synthesized. All compounds obtained have been characterized by IR, 1H NMR spectroscopy and X-ray crystallography. The effect of the electron donating and steric properties of ligand substituents on the structure of complexes is discussed. 相似文献
30.