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991.
Linear and semilinear second-order parabolic equations are considered. For these equations, we give a posteriori error estimates in the maximum norm that improve upon recent results in the literature. In particular it is shown that logarithmic dependence on the time step size can be eliminated. Semidiscrete and fully discrete versions of the backward Euler and of the Crank-Nicolson methods are considered. For their full discretizations, we use elliptic reconstructions that are, respectively, piecewise-constant and piecewise-linear in time. Certain bounds for the Green’s function of the parabolic operator are also employed. 相似文献
992.
The crew rostering problem in public bus transit aims at constructing personalized monthly schedules for all drivers. This problem is often formulated as a multi-objective optimization problem, since it considers the interests of both the management of bus companies and the drivers. Therefore, this paper attempts to solve the multi-objective crew rostering problem with the weighted sum of all objectives using ant colony optimization, simulated annealing, and tabu search methods. To the best of our knowledge, this is the first paper that attempts to solve the personalized crew rostering problem in public transit using different metaheuristics, especially the ant colony optimization. The developed algorithms are tested on numerical real-world instances, and the results are compared with ones solved by commercial solvers. 相似文献
993.
Koifman Oskar I. Lebedeva Natalia Sh. Gubarev Yury A. Koifman Mikhail O. 《Chemistry of Heterocyclic Compounds》2021,57(4):423-431
Chemistry of Heterocyclic Compounds - In this work, we analyze the latest data on the molecular docking of a range of SARS-CoV-2 proteins to protoporphyrin IX, verteporfin, and chlorin e6, as well... 相似文献
994.
Natalia Domenikou Ioannis Thanopulos Dionisis Stefanatos Vassilios Yannopapas Emmanuel Paspalakis 《Annalen der Physik》2023,535(2):2200478
A theoretical investigation on the population transfer in a Λ-type quantum system near a spherical gold nanoparticle under application of two stimulated Raman adiabatic passage (STIRAP) shortcuts and efficiency comparison with conventional STIRAP. It combines the density matrix approach for system dynamics, with classical electromagnetic calculations used to obtain the modified electric field amplitudes of the applied pulses and the Purcell factor of the quantum system due to the presence of the nanoparticle. The efficiency of population transfer is investigated by varying the distance between the quantum system and the nanoparticle, the free-space decay rate of quantum states, the mutual polarization, and the Rabi frequencies of each STIRAP shortcut pulses. In all cases, at least one of the applied shortcuts is more efficient than conventional STIRAP, while in most cases both perform better. When the pump and Stokes fields of the shortcuts have radial and tangential polarizations with respect to the nanoparticle surface, respectively, high transfer efficiency is obtained for small distances of the quantum system to the nanoparticle, moderate free space decay rates and large Rabi frequencies of the fields, while when the pulse polarizations are interchanged, the transfer becomes highly efficient only at large distances. 相似文献
995.
Yuri D. Ivanov Kristina A. Malsagova Vladimir P. Popov Igor N. Kupriyanov Tatyana O. Pleshakova Rafael A. Galiullin Vadim S. Ziborov Alexander Yu. Dolgoborodov Oleg F. Petrov Andrey V. Miakonkikh Konstantin V. Rudenko Alexander V. Glukhov Alexander Yu. Smirnov Dmitry Yu. Usachev Olga A. Gadzhieva Boris A. Bashiryan Vadim N. Shimansky Dmitry V. Enikeev Natalia V. Potoldykova Alexander I. Archakov 《Molecules (Basel, Switzerland)》2021,26(12)
The application of micro-Raman spectroscopy was used for characterization of structural features of the high-k stack (h-k) layer of “silicon-on-insulator” (SOI) nanowire (NW) chip (h-k-SOI-NW chip), including Al2O3 and HfO2 in various combinations after heat treatment from 425 to 1000 °C. After that, the NW structures h-k-SOI-NW chip was created using gas plasma etching optical lithography. The stability of the signals from the monocrine phase of HfO2 was shown. Significant differences were found in the elastic stresses of the silicon layers for very thick (>200 nm) Al2O3 layers. In the UV spectra of SOI layers of a silicon substrate with HfO2, shoulders in the Raman spectrum were observed at 480–490 cm−1 of single-phonon scattering. The h-k-SOI-NW chip created in this way has been used for the detection of DNA-oligonucleotide sequences (oDNA), that became a synthetic analog of circular RNA–circ-SHKBP1 associated with the development of glioma at a concentration of 1.1 × 10−16 M. The possibility of using such h-k-SOI NW chips for the detection of circ-SHKBP1 in blood plasma of patients diagnosed with neoplasm of uncertain nature of the brain and central nervous system was shown. 相似文献
996.
Kamil uczykowski Natalia Warmuziska Sylwia Operacz Iga Stryjak Joanna Bogusiewicz Julia Jacyna Renata Wawrzyniak Wiktoria Struck-Lewicka Micha J. Markuszewski Barbara Bojko 《Molecules (Basel, Switzerland)》2021,26(8)
Bladder cancer (BC) is a common malignancy of the urinary system and a leading cause of death worldwide. In this work, untargeted metabolomic profiling of biological fluids is presented as a non-invasive tool for bladder cancer biomarker discovery as a first step towards developing superior methods for detection, treatment, and prevention well as to further our current understanding of this disease. In this study, urine samples from 24 healthy volunteers and 24 BC patients were subjected to metabolomic profiling using high throughput solid-phase microextraction (SPME) in thin-film format and reversed-phase high-performance liquid chromatography coupled with a Q Exactive Focus Orbitrap mass spectrometer. The chemometric analysis enabled the selection of metabolites contributing to the observed separation of BC patients from the control group. Relevant differences were demonstrated for phenylalanine metabolism compounds, i.e., benzoic acid, hippuric acid, and 4-hydroxycinnamic acid. Furthermore, compounds involved in the metabolism of histidine, beta-alanine, and glycerophospholipids were also identified. Thin-film SPME can be efficiently used as an alternative approach to other traditional urine sample preparation methods, demonstrating the SPME technique as a simple and efficient tool for urinary metabolomics research. Moreover, this study’s results may support a better understanding of bladder cancer development and progression mechanisms. 相似文献
997.
998.
Remarkable Structural and Electronic Features of the Complex Formed by Trimeric Copper Pyrazolate with Pentaphosphaferrocene
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Dr. Oleg A. Filippov Aleksei A. Titov Ekaterina A. Guseva Dr. Dmitry A. Loginov Dr. Alexander F. Smol'yakov Dr. Fedor M. Dolgushin Prof. Natalia V. Belkova Prof. Lina M. Epstein Prof. Elena S. Shubina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(38):13176-13180
According to spectroscopic (NMR, IR, UV/Vis) study, the interaction of pentaphosphaferrocene [Cp*Fe(η5‐P5)] with trimeric copper pyrazolate [(Cu{3,5‐(CF3)2Pz})3] yields a new compound that is astonishingly stable in solution. Single‐crystal X‐ray analysis reveals unprecedented structural changes in the interacting molecules and the unique type of coordination [Cp*Fe(μ3‐η5:η2,η2‐P5){Cu(3,5‐(CF3)2Pz)}3]. As a result of the 90° macrocycle folding, the copper atoms are able to behave both as a Lewis acid and as a Lewis base in the interaction with the cyclo‐P5 ligand. 相似文献
999.
David Albesa‐Jov Fernanda Mendoza Ane Rodrigo‐Unzueta Fernando Gomolln‐Bel Javier O. Cifuente Saioa Urresti Natalia Comino Hansel Gmez Javier Romero‐García Jos M. Lluch Enea Sancho‐Vaello Xevi Biarns Antoni Planas Pedro Merino Laura Masgrau Marcelo E. Guerin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(34):10036-10040
Glycosyltransferases (GTs) comprise a prominent family of enzymes that play critical roles in a variety of cellular processes, including cell signaling, cell development, and host–pathogen interactions. Glycosyl transfer can proceed with either inversion or retention of the anomeric configuration with respect to the reaction substrates and products. The elucidation of the catalytic mechanism of retaining GTs remains a major challenge. A native ternary complex of a GT in a productive mode for catalysis is reported, that of the retaining glucosyl‐3‐phosphoglycerate synthase GpgS from M. tuberculosis in the presence of the sugar donor UDP‐Glc, the acceptor substrate phosphoglycerate, and the divalent cation cofactor. Through a combination of structural, chemical, enzymatic, molecular dynamics, and quantum‐mechanics/molecular‐mechanics (QM/MM) calculations, the catalytic mechanism was unraveled, thereby providing a strong experimental support for a front–side substrate‐assisted SNi‐type reaction. 相似文献
1000.
Electroless Deposition of III–V Semiconductor Nanostructures from Ionic Liquids at Room Temperature
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Dr. Abhishek Lahiri Dr. Natalia Borisenko Mark Olschewski René Gustus Janine Zahlbach Prof. Dr. Frank Endres 《Angewandte Chemie (International ed. in English)》2015,54(40):11870-11874
Group III–V semiconductor nanostructures are important materials in optoelectronic devices and are being researched in energy‐related fields. A simple approach for the synthesis of these semiconductors with well‐defined nanostructures is desired. Electroless deposition (galvanic displacement) is a fast and versatile technique for deposition of one material on another and depends on the redox potentials of the two materials. Herein we show that GaSb can be directly synthesized at room temperature by galvanic displacement of SbCl3/ionic liquid on electrodeposited Ga, on Ga nanowires, and also on commercial Ga. In situ AFM revealed the galvanic displacement process of Sb on Ga and showed that the displacement process continues even after the formation of GaSb. The bandgap of the deposited GaSb was 0.9±0.1 eV compared to its usual bandgap of 0.7 eV. By changing the cation in the ionic liquid, the redox process could be varied leading to GaSb with different optical properties. 相似文献