Experimental and theoretical study on diethyl-(Z)-2-(5,7-diphenyl-1,3,4-oxadiazepin-2-yl)-2-butenedioate using different levels of computational methods

2015 ◽  
Vol 140 ◽  
pp. 585-599 ◽  
Author(s):  
Z. Asadi ◽  
M.B. Asnaashariisfahani ◽  
E. Vessally ◽  
M.D. Esrafili
Keyword(s):  
Computational Methods ◽  
Theoretical Study ◽  
Different Levels

scholarly journals An experimental and theoretical study of the coordination and donor properties of tris-2-pyridyl-phosphine ligands

2020 ◽  
Vol 49 (16) ◽  
pp. 5312-5322 ◽  
Author(s):  
Schirin Hanf ◽  
Annie L. Colebatch ◽  
Philipp Stehr ◽  
Raúl García-Rodríguez ◽  
Evamarie Hey-Hawkins ◽  
...  
Keyword(s):  
Computational Methods ◽  
Theoretical Study ◽  
Phosphine Ligands

The donor properties of a range of multidentate 2-pyridyl-phosphines were evaluated using different experimental and computational methods.

RELATIONSHIPS BETWEEN DIFFERENT-ORDER POLARIZABILITIES AND GROUND STATE DIPOLE MOMENT

2013 ◽  
Vol 12 (01) ◽  
pp. 1250099 ◽  
Author(s):  
K. HATUA ◽  
PRASANTA K. NANDI
Keyword(s):  
Dipole Moment ◽  
Ground State ◽  
Rational Design ◽  
Theoretical Study ◽  
Basis Sets ◽  
Ground State Dipole Moment ◽  
Donor Acceptor ◽  
Equilibrium Structures ◽  
Different Order ◽  
Different Levels

A number of charge transferring molecules with varying electron donor, acceptor and π-conjugative paths have been considered for the theoretical study of their NLO properties in terms of the linear polarizability and the ground state dipole moment. The equilibrium structures are calculated at the HF, MP2 and B3LYP levels, respectively. The longitudinal components of NLO coefficients are calculated by using HF, MP2, B3LYP, BHHLYP, CAM-B3LYP, and wB97XD methods for 6-31+G(p,d) and 6-311++G(p,d) basis sets. The hyperpolarizabilities obtained at different levels of calculation showed a fairly consistent trend. The relationships between hyperpolarizabilities, polarizability and ground state dipole moment have been proposed by considering only the two-level term in the standard sum-over-state (SOS) expressions and the generalized Thomas–Kuhn (TK) sum rule. The ab initio calculated first- and second-hyperpolarizabilities fairly correlate with the reduced 2-level contributions relating to the linear polarizability and ground state dipole moment. For a given length of conjugation the stronger enhancement of cubic polarizability arises from the increase of quadratic polarizability for comparable values of linear polarizability and dipole moment. The idea developed in the present work can be used to make a rational design of potential NLO-phores.

scholarly journals On the role of aromatic-sugar interactions in the molecular recognition of carbohydrates: A 3D view by using NMR

2008 ◽  
Vol 80 (8) ◽  
pp. 1827-1835 ◽  
Author(s):  
M. Dolores Díaz ◽  
María del Carmen Fernández-Alonso ◽  
Gabriel Cuevas ◽  
F. Javier Cañada ◽  
Jesús Jiménez-Barbero
Keyword(s):  
Molecular Recognition ◽  
Computational Methods ◽  
Theoretical Approach ◽  
Different Levels

This revision describes an up-to-date review of our efforts to investigate the interaction of carbohydrates with aromatic moieties at different levels of complexity. Protein-sugar interactions have been studied using NMR experiments on a variety of hevein/chitooligosaccharide systems. In addition, NMR and computational methods have also been used to evaluate the interaction of simple aromatic entities with simple monosaccharides. In between, the stacking features of aromatic-containing glycomolecules have also been described by using an analogous experimental-theoretical approach.

Effect of groundwater on the displacements of axially loaded pile in clayey soil

2021 ◽  
Author(s):  
Tawfek Sheer Ali ◽  
Nassr Salman ◽  
Mohammed K. Fakhraldin
Keyword(s):  
Theoretical Study ◽  
Clayey Soil ◽  
Ground Surface ◽  
Horizontal Displacement ◽  
Soil Mass ◽  
Concrete Piles ◽  
Finite Element Package ◽  
Different Levels ◽  
Plaxis 3D ◽  
Horizontal Displacements

Abstract The displacement of a loaded pile could be vertical (axial) or horizontal (lateral); these displacements are sensitive to groundwater presence within the soil mass. This paper presents a theoretical study to investigate vertical and horizontal displacement of piles embedded in a clayey soil for different levels of groundwater under the ground surface. The study was performed using the commercial finite element package PLAXIS-3D. Three diameters of the concrete piles were considered: 0.5, 0.75 and 1 m, and were subjected to 1,000 kN axial load. The effect of 0, 5, 10, 15 and 20 m groundwater along the 20 m pile in length from the ground surface on the vertical and horizontal displacements was investigated. The results indicated that the vertical and horizontal displacements increase when the ground water level increases towards the base of pile. Also, there is a significant increase in the horizontal displacement up to 15 m of groundwater level from ground surface and decreased at levels from 15 to 20 m.

A Detailed Theoretical Study of the Thermal Conductivity of Bi2(Te0.85Se0.15)3 Single Crystals

2012 ◽  
Vol 1404 ◽  
Author(s):  
Ö. Ceyda Yelgel ◽  
Gyaneshwar P. Srivastava
Keyword(s):  
Thermal Conductivity ◽  
Single Crystals ◽  
Theoretical Investigation ◽  
Theoretical Study ◽  
Single Mode ◽  
Debye Model ◽  
Electron Hole ◽  
Electron Hole Pair ◽  
N Doping ◽  
Different Levels

ABSTRACTWe present a theoretical investigation of the thermal conductivity for n-type doped Bi2(Te0.85Se0.15)3 single crystals by using the Debye model within the single-mode relaxationtime approximation. A detailed account of alloy, electron-phonon, phonon-phonon and electron-hole pair (bipolar) interactions are included. Different levels (0.1 and 0.05 wt.%) of n-doping from CuBr and SbI3 dopants were considered. The calculated conductivity, by combining lattice (κ ph) and electronic bipolar (κ bp) contributions, successfully explains the experimental results obtained by Hyun et al. [J. Mat. Sci. 33 5595 (1998)]. The κ ph contribution was calculated using Srivastava’s scheme and the κ bp contribution was obtained by employing Price’s theory.

scholarly journals Móviles y pantallas en edades tempranas: convivencia digital, derechos de la infancia y responsabilidad adulta

2021 ◽  
pp. 1
Author(s):  
Mari Carmen Caldeiro Pedreira ◽  
Ana Castro Zubizarreta ◽  
Tereza Havránková
Keyword(s):  
Mobile Devices ◽  
Theoretical Study ◽  
Social Criticism ◽  
Digital Age ◽  
Children's Rights ◽  
The Other ◽  
Early Age ◽  
The Media ◽  
Different Levels ◽  
Screen Use

In the hypermedia society the indiscriminate use of multiple screens is observed from an increasingly early age. For this reason, digital coexistence, respect for children’s rights, and a sense of responsibility from the media and from families who educate children are required. This study reviews the literature in this field and identifies two approaches to the use of mobile devices in childhood. One approach highlights the uses of such devices as well as the opportunities they provide for children’s education and personal enrichment, whereas the other highlights their abu- sive uses and the problems caused by using them. This theoretical study reviews and reflects on the ideas of numerous authors who – in this digital age when society in general and children in parti- cular are using technology – are committed to empowering children to become critical receptors. Bearing in mind that childhood and the media cohabit the same space and that different children are engaged in different levels of media activity, we propose a range of levels that are based on activity, creation and social criticism. This proposal is achievable if we take into account education in, with and for the media. The CRC also recommends that families and schools should encourage suitable media and screen use by children.

scholarly journals Applications of analysis of dynamic adaptations in parameter trajectories

2013 ◽  
Vol 3 (2) ◽  
pp. 20120084 ◽  
Author(s):  
Natal A. W. van Riel ◽  
Christian A. Tiemann ◽  
Joep Vanlier ◽  
Peter A. J. Hilbers
Keyword(s):  
Theoretical Study ◽  
Computational Modelling ◽  
Lipoprotein Metabolism ◽  
Molecular Data ◽  
Model Parameters ◽  
Cover Time ◽  
Preclinical Research ◽  
Dynamic Changes ◽  
Metabolic Adaptations ◽  
Different Levels

Metabolic profiling in combination with pathway-based analyses and computational modelling are becoming increasingly important in clinical and preclinical research. Modelling multi-factorial, progressive diseases requires the integration of molecular data at the metabolome, proteome and transcriptome levels. Also the dynamic interaction of organs and tissues needs to be considered. The processes involved cover time scales that are several orders of magnitude different. We report applications of a computational approach to bridge the scales and different levels of biological detail. Analysis of dynamic adaptations in parameter trajectories (ADAPTs) aims to investigate phenotype transitions during disease development and after a therapeutic intervention. ADAPT is based on a time-dependent evolution of model parameters to describe the dynamics of metabolic adaptations. The progression of metabolic adaptations is predicted by identifying necessary dynamic changes in the model parameters to describe the transition between experimental data obtained during different stages. To get a better understanding of the concept, the ADAPT approach is illustrated in a theoretical study. Its application in research on progressive changes in lipoprotein metabolism is also discussed.

scholarly journals Vaccine-induced pathogen strain replacement: what are the mechanisms?

2007 ◽  
Vol 5 (18) ◽  
pp. 3-13 ◽  
Author(s):  
Maia Martcheva ◽  
Benjamin M Bolker ◽  
Robert D Holt
Keyword(s):  
Life History Traits ◽  
Theoretical Study ◽  
Current Model ◽  
Population Level ◽  
Differential Effectiveness ◽  
Review Reports ◽  
Pathogen Populations ◽  
Vaccination Campaigns ◽  
Different Levels ◽  
Pathogen Strains

Host immune systems impose natural selection on pathogen populations, which respond by evolving different antigenic signatures. Like many evolutionary processes, pathogen evolution reflects an interaction between different levels of selection; pathogens can win in between-strain competition by taking over individual hosts (within-host level) or by infecting more hosts (population level). Vaccination, which intensifies and modifies selection by protecting hosts against one or more pathogen strains, can drive the emergence of new dominant pathogen strains—a phenomenon called vaccine-induced pathogen strain replacement . Here, we review reports of increased incidence of subdominant variants after vaccination campaigns and extend the current model for pathogen strain replacement, which assumes that pathogen strain replacement occurs only through the differential effectiveness of vaccines against different pathogen strains. Based on a recent theoretical study, we suggest a broader range of possible mechanisms, some of which allow pathogen strain replacement even when vaccines are perfect —that is, they protect all vaccinated individuals completely against all pathogen strains. We draw an analogy with ecological and evolutionary explanations for competitive dominance and coexistence that allow for tradeoffs between different competitive and life-history traits.

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