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131.
Yu. N. Khanin E. E. Vdovin A. Mishchenko J. S. Tu A. Kozikov R. V. Gorbachev K. S. Novoselov 《JETP Letters》2016,103(5):334-340
The spectral and total electron densities of states in two-dimensional FeAs clusters, which simulate iron-based superconductors, have been calculated using the generalized quantum Monte Carlo algorithm within the full two-orbital model. Spectra have been reconstructed by solving the integral equation relating the Matsubara Green’s function and spectral density by the method combining the gradient descent and Monte Carlo algorithms. The calculations have been performed for clusters with dimensions up to 10 × 10 FeAs cells. The profiles of the Fermi surface for the entire Brillouin zone have been presented in the quasiparticle approximation. Data for the total density of states near the Fermi level have been obtained. The effect of the interaction parameter, size of the cluster, and temperature on the spectrum of excitations has been studied. 相似文献
132.
Universal classes of Abelian groups are classified in terms of sets of finitely generated groups closed with respect to the discrimination operator. The notions of a principal universal class and a canonical group for such a class are introduced. For any universal class K, the class Kec of existentially closed groups generated by the universal theory of K is described. It is proved that Kec is axiomatizable and, therefore, the universal theory of K has a model companion. 相似文献
133.
S. P. Mishchenko 《Moscow University Mathematics Bulletin》2016,71(3):115-118
The existence of an almost nilpotent variety of linear algebras with noninteger exponent is proved. Examples of almost nilpotent varieties with integer exponents were only known so far. 相似文献
134.
Sokolov MN Gushchin AL Kovalenko KA Peresypkina EV Virovets AV Sanchiz J Fedin VP 《Inorganic chemistry》2007,46(6):2115-2123
The reaction of aqueous [W3S7(C2O4)3](2-) with Ln(3+) and Th(4+) in a 1:1 molar ratio leads to oxalate-bridged heteropolynuclear molecular complexes and coordination polymers. La(3+) and Ce(3+) give a layered structure with big (about 1.8 nm) honeycomb pores which are filled with water molecules and lanthanide ions, in {[Ln(H2O)6]3[W3S7(C2O4)3]4}Br x xH2O (Ia and Ib). The smaller Pr(3+), Nd(3+), Sm(3+), Eu(3+), and Gd(3+) ions give discrete nanomolecules [(W3S7(C2O4)3Ln(H2O)5)2(mu-C2O4)] (with a separation of about 3.2 nm between the most distant parts of the molecule), which are further united into zigzag chains by specific S2...Br- contacts to achieve the overall stoichiometry K[(W3S7(C2O4)3Ln(H2O)5)2(mu-C2O4)]Br.xH2O (IIa-IId). Th(4+) gives K2[(W3S7(C2O4)3)4Th2(OH)2(H2O)10] x 14.33H2O (III) with a nanosized discrete anion (with a separation of about 2.7 nm between the most distant parts of the molecule), in which two thorium atoms are bound via two hydroxide groups into the Th2(OH)2(6+) unit, and each Th is further coordinated by five water molecules and two monodentate [W3S7(C2O4)](2-) cluster ligands. All compounds were characterized by X-ray structure analysis and IR spectroscopy. Magnetic susceptibility measurements in the temperature range of 2-300 K show weak antiferromagnetic interactions between two lanthanides atoms for compounds IIa, IIb, and IId. The thermal decomposition of Ia, Ib, and IIb was studied by thermogravimetry. 相似文献
135.
Sokolov MN Gushchin AL Abramov PA Virovets AV Peresypkina EV Fedin VP 《Inorganic chemistry》2007,46(11):4677-4682
New ternary and quaternary molybdenum cluster chalcohalides were obtained by high-temperature reactions between Mo, chalcogens, and halogens in evacuated ampules. The crystal structures of [Mo3Se7(TeBr3)Br2]2[Te2Br10] (1), [Mo3Se7(TeI3)I2]I (2), and [Mo3Te7(TeI3)3]2(I)(TeI3) (3) were determined by single-crystal X-ray diffraction. The structures of 1 and 2 consist of positively charged zigzag chains infinity1 [Mo3Se7(TeX3)X4/2] (X=Br, I), with Te2Br102- and I-, respectively, as counterions. The TeI3- and TeBr3- ions function as bidentate ligands in 1 and 2. In 3, TeI3- is not coordinated to the metal but acts as a counterion to the [Mo3Te7(TeI3)3]+ cluster cation. 相似文献
136.
Evdokimov NM Kireev AS Yakovenko AA Antipin MY Magedov IV Kornienko A 《The Journal of organic chemistry》2007,72(9):3443-3453
Heterocyclic privileged medicinal scaffolds involving pyridine, 1,4-dihydropyridine, chromeno[2,3-b]pyridine, and dihydro-1,4-dithiepine frameworks are prepared via a single-step multicomponent reaction of structurally diverse aldehydes with various thiols and malononitrile. Mechanistic studies of the synthetic pathway leading to pyridines reveal that 1,4-dihydropyridines undergo oxidation by the intermediate Knoevenagel adducts rather than by air oxygen. The use of o,o'-disubstituted aromatic aldehydes leads to the corresponding 1,4-dihydropyridines, whereas salicylic aldehydes result in chromeno[2,3-b]pyridines. Reactions of ethanedithiol as a thiol component produce dimeric pyridines with sterically unencumbered aldehydes, while o,o'-disubstituted aromatic aldehydes give dihydro-1,4-dithiepines. Thus, depending on the aldehyde and thiol types, diverse libraries of medicinally relevant compounds can be prepared by a simple one-step process involving no chromatography. 相似文献
137.
We use a Flory-Huggins type approach and the random phase approximation (RPA) to describe a microphase separation in the mixture of ionic and nonionic liquids. The mixture is modeled as a "three-component" system including anions, cations, and neutral molecules. Each ion is considered to consist of a charged group surrounded by a neutral "bulky" shell. The shells of the anion and cation are assumed to have different affinities to the neutral molecules. We show that, if the difference of the Flory-Huggins parameters describing affinities of the anions and cations to the neutral molecules is higher than a certain value, the microphase separation can occur. The physical reason for the separation is a delicate balance between the short-range segregating interactions and the long-range Coulomb interactions. 相似文献
138.
Stela Georgieva Artem Bezfamilnyi Anton Georgiev Marian Varbanov 《Molecules (Basel, Switzerland)》2021,26(19)
Herein, the spectral and electrochemical characterizations of three different substituted N-phthalimide azo-azomethine (NAA) dyes (L) containing an o-hydroxy group and their NAA-M(II) chelates [M(II): Cu, Ni, Co, Pb] were reported by using UV–Vis and fluorescence spectroscopy and potentiometric and voltamperometric techniques. The pK value of the dyes as well as the stoichiometry and stability of the NAA-metal chelates were studied, and the stoichiometry was found to be mostly 1:2 (ML2) with high complex stability constant values. The sensor activity of N-phthalimide azo-azomethine derivatives toward pH and metal ions has been also investigated and tested for indicator application in acid–base analysis and detection of Cu(II) ions in real samples of surface river water using voltamperometric detection. The results showed that one of the ligands possesses the highest electrochemical response upon binding to copper ions and could be successfully used in the analysis of copper in water at a concentration range of the analyte from 3.7 × 10−7 to 5.0 × 10−6 mol L−1, with analytical characteristics of the method being Sr = 1.5%, LOD = 3.58 µg L−1 and LOQ =11.9 µg L−1 相似文献
139.
It is shown that if X is an n – dimensional subspace of Lp, 0 < p < 1, then there exists a subspace Y of 𝓁Np such that d(X, Y) ≤ 1 + ε and N ≤ C(ε, p)n(log n)3. 相似文献
140.
Francesco Gentile Michael Fernandez Fuqiang Ban Anh-Tien Ton Hazem Mslati Carl F. Perez Eric Leblanc Jean Charle Yaacoub James Gleave Abraham Stern Bill Wong Franois Jean Natalie Strynadka Artem Cherkasov 《Chemical science》2021,12(48):15960
Recent explosive growth of ‘make-on-demand’ chemical libraries brought unprecedented opportunities but also significant challenges to the field of computer-aided drug discovery. To address this expansion of the accessible chemical universe, molecular docking needs to accurately rank billions of chemical structures, calling for the development of automated hit-selecting protocols to minimize human intervention and error. Herein, we report the development of an artificial intelligence-driven virtual screening pipeline that utilizes Deep Docking with Autodock GPU, Glide SP, FRED, ICM and QuickVina2 programs to screen 40 billion molecules against SARS-CoV-2 main protease (Mpro). This campaign returned a significant number of experimentally confirmed inhibitors of Mpro enzyme, and also enabled to benchmark the performance of twenty-eight hit-selecting strategies of various degrees of stringency and automation. These findings provide new starting scaffolds for hit-to-lead optimization campaigns against Mpro and encourage the development of fully automated end-to-end drug discovery protocols integrating machine learning and human expertise.Deep learning-accelerated docking coupled with computational hit selection strategies enable the identification of inhibitors for the SARS-CoV-2 main protease from a chemical library of 40 billion small molecules. 相似文献