scholarly journals Experimental and theoretical studies on thymine photodimerization mediated by oxidatively generated DNA lesions and epigenetic intermediates

2020 ◽  
Vol 22 (44) ◽  
pp. 25661-25668
Author(s):  
Mauricio Lineros-Rosa ◽  
Antonio Francés-Monerris ◽  
Antonio Monari ◽  
Miguel Angel Miranda ◽  
Virginie Lhiaubet-Vallet
Keyword(s):  
Dna Lesions ◽  
Theoretical Studies ◽  
Computational Studies ◽  
Thymine Dimers ◽  
Different Types ◽  
Experimental And Theoretical Studies

Combined spectroscopic and computational studies reveal that, in spite of their structural similarities, 5-formyluracil and 5-formylcytosine photosensitize cyclobutane thymine dimers through two different types of mechanisms.

scholarly journals The inside view of an oscillating pipe

2016 ◽  
Vol 808 ◽  
pp. 1-4
Author(s):  
Yahya Modarres-Sadeghi
Keyword(s):  
Nonlinear Dynamics ◽  
Model Problem ◽  
Theoretical Studies ◽  
Pipe Conveying Fluid ◽  
Fluid Structure Interactions ◽  
Routes To Chaos ◽  
Different Types ◽  
Inside View ◽  
Experimental And Theoretical Studies ◽  
Conveying Fluid

A pipe conveying fluid is a model problem in fluid–structure interactions and nonlinear dynamics. Several experimental and theoretical studies exist on this problem and very rich nonlinear dynamics have been observed including super- and subcritical instabilities as well as various routes to chaos. Despite all the existing studies, we had not yet seen the fluid inside an oscillating pipe as the pipe undergoes different types of flow-induced instabilities. But the wait is over.

METHODS OF MODELING AND CALCULATION OF REINFORCED CONCRETE STRUCTURES OF OPERATED GTS, REINFORCED WITH PRESTRESSED BASALT COMPOSITE REINFORCEMENT

2021 ◽  
pp. 59-67
Author(s):  
E. N. BELLENDIR ◽  
◽  
O. D. RUBIN ◽  
S. E. LISICHKIN ◽  
I. V. BAKLYKOV
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Hydraulic Structures ◽  
Reinforced Concrete Structures ◽  
Theoretical Studies ◽  
Computational Studies ◽  
Ansys Software ◽  
Nite Element ◽  
Experimental And Theoretical Studies ◽  
Composite Reinforcement

The development of a methodology for numerical modeling and calculation of reinforced concrete structures of operated hydraulic structures, reinforced with prestressed basalt composite reinforcement, including on the basis of experimental research data carried out in the branch of JSC“Institute Hydroproject”-“NIIES” is presented. Computational studies were carried out on the basis of spatial fi nite element models in the framework of the ANSYS software package. Developing the models, the results of experimental and theoretical studies of hydrotechnical reinforced concrete structures were used in which prestressed basalt composite reinforcement is placed both in the tensioned and compressed zones of the structures.

scholarly journals Teaching an old carbocation new tricks: Intermolecular C–H insertion reactions of vinyl cations

Science ◽  
2018 ◽  
Vol 361 (6400) ◽  
pp. 381-387 ◽  
Author(s):  
Stasik Popov ◽  
Brian Shao ◽  
Alex L. Bagdasarian ◽  
Tyler R. Benton ◽  
Luyi Zou ◽  
...  
Keyword(s):  
Theoretical Studies ◽  
Computational Studies ◽  
Mechanistic Studies ◽  
Insertion Reactions ◽  
Bond Forming ◽  
The Past ◽  
Carbon Carbon Bond ◽  
Transition Structures ◽  
The Subject ◽  
Experimental And Theoretical Studies

Vinyl carbocations have been the subject of extensive experimental and theoretical studies over the past five decades. Despite this long history in chemistry, the utility of vinyl cations in chemical synthesis has been limited, with most reactivity studies focusing on solvolysis reactions or intramolecular processes. Here we report synthetic and mechanistic studies of vinyl cations generated through silylium–weakly coordinating anion catalysis. We find that these reactive intermediates undergo mild intermolecular carbon-carbon bond–forming reactions, including carbon-hydrogen (C–H) insertion into unactivated sp3 C–H bonds and reductive Friedel-Crafts reactions with arenes. Moreover, we conducted computational studies of these alkane C–H functionalization reactions and discovered that they proceed through nonclassical, ambimodal transition structures. This reaction manifold provides a framework for the catalytic functionalization of hydrocarbons using simple ketone derivatives.

scholarly journals Synthesis of 3-alkoxypropan-1,2-diols from glycidol: experimental and theoretical studies for the optimization of the synthesis of glycerol derived solvents

2017 ◽  
Vol 19 (17) ◽  
pp. 4176-4185 ◽  
Author(s):  
A. Leal-Duaso ◽  
M. Caballero ◽  
A. Urriolabeitia ◽  
J. A. Mayoral ◽  
J. I. García ◽  
...  
Keyword(s):  
Green Synthesis ◽  
Theoretical Studies ◽  
Computational Studies ◽  
Experimental And Theoretical Studies

Optimized green synthesis of glyceryl monoethers from alcohols and glycidol through experimental and computational studies.

scholarly journals STUDY OF THE PASTE-LIKE PROPELLANT COMBUSTION AT VARIOUS LOADING SCHEMES

2020 ◽  
pp. 89-101
Author(s):  
Viktor V. BURKIN ◽  
◽  
Aleksey S. D’YACHKOVSKIY ◽  
Aleksandr N. ISHCHENKO ◽  
Vladimir Z. KASIMOV ◽  
...  
Keyword(s):  
Maximum Pressure ◽  
Theoretical Studies ◽  
Powder Charge ◽  
Propellant Combustion ◽  
Dispersion Law ◽  
Different Types ◽  
Propellant Charge ◽  
The Mathematical Model ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

The experimental and theoretical studies of the paste-like propellant combustion in a model ballistic installation are implemented. The research is carried out using three masses of projectile assemblies and three types of the propellant charge. The paper presents two versions of the law of dispersion for paste-like propellants which allow accounting for the pressure on the front and acceleration of the projectile assembly with a traveling charge. The coefficients in the laws of dispersion are obtained. Using the mathematical model presented in this work, the gas-dynamic pictures of the shots when the propellants are applied as traveling charges are obtained for each dispersion law. Based on the results, a detailed study of the processes occurring with the traveling charge consisting of a model paste-like propellant is implemented for various shot arrangements. The discrepancy between theoretical results and the results obtained in the set of experiments is no more than 2% for the maximum pressure and no more than 1% for the muzzle velocity. The dispersion law accounting for the projectile assembly acceleration and traveling charge makes it possible to describe accurately the processes in the space behind the projectile for projectile assemblies of various masses and different types of granulated powder charge in terms of the model ballistic installation in the considered pressure range.

The Stabilizing Effect of Pre-Equilibria: A Trifluoromethyl Complex as CF2 Reservoir in Catalytic Olefin Difluorocarbenation

2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  
Keyword(s):  
High Selectivity ◽  
Side Reactions ◽  
Theoretical Studies ◽  
Attractive Feature ◽  
Catalyst Recovery ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Experimental And Theoretical Studies

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.

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