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71.
Izabela Pospieszna‐Markiewicz Micha Kozowski Wanda Radecka‐Paryzek Maciej Kubicki 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):o559-o561
In the title potential O,N,N′,O′‐tetradentate Schiff base ligand {systematic name: 2,2′‐[pentane‐1,5‐diylbis(nitrilomethylidyne)]diphenol}, C19H22N2O2, the mutual orientation of the three planar fragments determines the conformation of the molecule. The dihedral angles between the planes of the two salicylidene groups and the plane of the central extended pentane chain are 78.4 (2) and 62.0 (3)°, and the angle between the terminal ring planes is 55.4 (1)°. Strong intramolecular O—H...N hydrogen bonds close almost‐planar six‐membered rings, and the O—H bonds are elongated as a result of hydrogen‐bond formation. 相似文献
72.
R.S. Markiewicz Susmita Basak A. Bansil 《Journal of Electron Spectroscopy and Related Phenomena》2010,181(1):23-27
We demonstrate that many features ascribed to strong correlation effects in various spectroscopies of the cuprates are captured by a calculation of the self-energy incorporating effects of spin and charge fluctuations. The self-energy is calculated over the full doping range from half-filling to the overdoped system. In the normal state, the spectral function reveals four subbands: two widely split incoherent bands representing the remnant of the two Hubbard bands, and two additional coherent, spin- and charge-dressed in-gap bands split by a spin-density wave, which collapses in the overdoped regime. The resulting coherent subbands closely resemble our earlier mean-field results. Here we present an overview of the combined results of our mean-field calculations and the newer extensions into the intermediate coupling regime. 相似文献
73.
Nicolas Leconte Bertrand Langrand Eric Markiewicz 《Journal of Computational and Applied Mathematics》2008
The paper deals with the modelling of riveted assemblies for full-scale complete aircraft crashworthiness. Many comparisons between experiments and FE computations of bird impacts onto aluminium riveted panels have shown that macroscopic plastic strains were not sufficiently developed (and localised) in the riveted shell FE in the impact area. Consequently, FE models never succeed in initialising and propagating the rupture in the sheet metal plates and along rivet rows as shown by experiments, without calibrating the input data (especially the damage and failure properties of the riveted shell FE). To model the assembly correctly, it appears necessary to investigate on FE techniques such as Hybrid-Trefftz finite element method (H-T FEM). Indeed, perforated FE plates developed for elastic problems, based on a Hybrid-Trefftz formulation, have been found in the open literature. Our purpose is to find a way to extend this formulation so that the super-element can be used for crashworthiness. To reach this aim, the main features of an elastic Hybrid-Trefftz plate are presented and are then followed by a discussion on the possible extensions. Finally, the interpolation functions of the element are evaluated numerically. 相似文献
74.
The growth of the science and technology of plastics leads to the development of new materials with more desirable properties. Such kinds of materials include polyurethanes with isocyanurate structural units combining the properties of great strength and high temperature stability. Most of them are produced as rigid foams designed as insulation materials for industrial applications. However, great progress has been made with the introduction of isocyanurate rings in the non‐cellular areas, especially in elastomers. The aim of this work is to present an overview of the major developments on the field of poly(urethane‐isocyanurate) elastomers. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
75.
R.L. Aurbach L. Eaves R.S. Markiewicz P.L. Richards 《Solid State Communications》1976,19(11):1023-1025
The far-infrared attenuation spectrum due to a large electron-hole drop in inhomogeneously stressed Ge has been measured and compared to the attenuation by small drops in unstressed Ge. The spectrum is analyzed using the full Mie theory for the absorption due to a large sphere; the experimental results are interpreted as bulk plasma absorption in a drop with pair density considerably lowered by the strain. 相似文献
76.
Natalia Kleczewska Pawel J. Sikorski Zofia Warminska Lukasz Markiewicz Renata Kasprzyk Natalia Baran Karina Kwapiszewska Aneta Karpinska Jaroslaw Michalski Robert Holyst Joanna Kowalska Jacek Jemielity 《Chemical science》2021,12(30):10242
Targeting cap-dependent translation initiation is one of the experimental approaches that could lead to the development of novel anti-cancer therapies. Synthetic dinucleoside 5′,5′-triphosphates cap analogs are potent antagonists of eukaryotic translation initiation factor 4E (eIF4E) in vitro and could counteract elevated levels of eIF4E in cancer cells; however, transformation of these compounds into therapeutic agents remains challenging – they do not easily penetrate into cells and are susceptible to enzymatic cleavage. Here, we tested the potential of several small molecule ligands – folic acid, biotin, glucose, and cholesterol – to deliver both hydrolyzable and cleavage-resistant cap analogs into cells. A broad structure–activity relationship (SAR) study using model fluorescent probes and cap–ligand conjugates showed that cholesterol greatly facilitates uptake of cap analogs without disturbing the interactions with eIF4E. The most potent cholesterol conjugate identified showed apoptosis-mediated cytotoxicity towards cancer cells.Ligand assisted cellular delivery of negatively charged dinucleotides, which are potential antagonists of the protooncogenic protein eIF4E. 相似文献
77.
Uszczyńska B Ratajczak T Frydrych E Maciejewski H Figlerowicz M Markiewicz WT Chmielewski MK 《Lab on a chip》2012,12(6):1151-1156
The copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction was applied as the novel method of DNA immobilization on a modified solid support. The CuAAC click reaction enables the covalent binding of DNA modified with pentynyl groups at its 5'-end to azide-loaded slides. Click microarrays were produced using this approach and successfully employed in biological/model experiments. 相似文献
78.
Roksana Słowik 《Linear and Multilinear Algebra》2013,61(5):667-677
We study the real elements in triangular matrix groups. We describe some classes of elements that are real in T n (K) – the groups of upper triangular matrices over a commutative field K. From the obtained results there follow some applications for finding real elements in general linear groups – GL n (K). 相似文献
79.
It has previously been shown that, in an electron-hole drop (EHD) produced in 〈11〉 -stressed Ge, a large population of electrons can be maintained in the strain-split-off (α3) electron valleys. The density and binding energy of these EHD are calculated on the assumption that the drops contain a single phase with a fixed ratio of α3 to α1 electrons. This ratio can be varied experimentally, and the observed densities as a function of α3 electron fraction are in good agreement with theory. 相似文献
80.
This paper develops the concept of a contour of complete nonuniqueness and shows its application to the optimal design (optimal layout) of simple trusses transmitting a concentrated force to a presscribed, arbitrary foundation contour. As an example, a symmetric two-bar truss with compressed bars is considered, and the constraints refer to various kinds of elastic instability of the system.Grant No. 05-12-10.2 of the Polish Academy of Sciences is gratefully acknowledged. 相似文献