The Role of Nucleobase Carboradical and Carbanion on DNA Lesions:  A Theoretical Study

2006 ◽  
Vol 110 (46) ◽  
pp. 23583-23589 ◽  
Author(s):  
Ru bo Zhang ◽  
Leif A. Eriksson
Keyword(s):  
Theoretical Study ◽  
Dna Lesions

Role of Man in Production and Social Systems Based on Digital Technologies

2020 ◽  
pp. 6-13
Author(s):  
V. K. Potemkin
Keyword(s):  
Theoretical Study ◽  
Social Systems ◽  
Digital Technologies ◽  
Changing Role ◽  
Consistent Approach ◽  
Social Improvement

The article presents the results of a theoretical study of the influence processes of the developed digital technologies and the activities of enterprises and organizations on the changing role of man in labor and their social improvement. The necessity of a balanced and consistent approach to create conditions for the use of digital technologies in practical activities and determining the con- sequences not only in enterprises and organizations, but also in the conscious behavior and social realities of all workers, without exception, is substantiated. The main directions of the development of digital technologies are determined, involving the wide participation of workers in their use in enterprises and organizations.

scholarly journals The Role of La2O3 in Enhancement the Radiation Shielding Efficiency of the Tellurite Glasses: Monte-Carlo Simulation and Theoretical Study

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3913
Author(s):  
Aljawhara H. Almuqrin ◽  
Mohamed Hanfi ◽  
K. G. Mahmoud ◽  
M. I. Sayyed ◽  
Hanan Al-Ghamdi ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Theoretical Study ◽  
Radiation Shielding ◽  
Photon Flux ◽  
Transmission Factor ◽  
Tellurite Glasses ◽  
Attenuation Coefficients ◽  
Binary Glass ◽  
Buildup Factors

The radiation shielding competence was examined for a binary glass system xLa2O3 + (1 − x) TeO2 where x = 5, 7, 10, 15, and 20 mol% using MCNP-5 code. The linear attenuation coefficients (LACs) of the glasses were evaluated, and it was found that LT20 glass has the greatest LAC, while LT5 had the least LAC. The transmission factor (TF) of the glasses was evaluated against thicknesses at various selected energies and was observed to greatly decrease with increasing thickness; for example, at 1.332 MeV, the TF of the LT5 glass decreased from 0.76 to 0.25 as the thickness increased from 1 to 5 cm. The equivalent atomic number (Zeq) of the glasses gradually increased with increasing photon energy above 0.1 MeV, with the maximum values observed at around 1 MeV. The buildup factors were determined to evaluate the accumulation of photon flux, and it was found that the maximum values for both can be seen at around 0.8 MeV. This research concluded that LT20 has the greatest potential in radiation shielding applications out of the investigated glasses due to the glass having the most desirable parameters.

scholarly journals Theoretical Study on the Photo-Oxidation and Photoreduction of an Azetidine Derivative as a Model of DNA Repair

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2911
Author(s):  
Miriam Navarrete-Miguel ◽  
Antonio Francés-Monerris ◽  
Miguel A. Miranda ◽  
Virginie Lhiaubet-Vallet ◽  
Daniel Roca-Sanjuán
Keyword(s):  
Electron Transfer ◽  
Energy Barrier ◽  
Ring Opening ◽  
Dna Lesions ◽  
Barrier Heights ◽  
Dna Lesion ◽  
Electron Reduction ◽  
The Stability ◽  
Electron Transfer Processes

Photocycloreversion plays a central role in the study of the repair of DNA lesions, reverting them into the original pyrimidine nucleobases. Particularly, among the proposed mechanisms for the repair of DNA (6-4) photoproducts by photolyases, it has been suggested that it takes place through an intermediate characterized by a four-membered heterocyclic oxetane or azetidine ring, whose opening requires the reduction of the fused nucleobases. The specific role of this electron transfer step and its impact on the ring opening energetics remain to be understood. These processes are studied herein by means of quantum-chemical calculations on the two azetidine stereoisomers obtained from photocycloaddition between 6-azauracil and cyclohexene. First, we analyze the efficiency of the electron-transfer processes by computing the redox properties of the azetidine isomers as well as those of a series of aromatic photosensitizers acting as photoreductants and photo-oxidants. We find certain stereodifferentiation favoring oxidation of the cis-isomer, in agreement with previous experimental data. Second, we determine the reaction profiles of the ring-opening mechanism of the cationic, neutral, and anionic systems and assess their feasibility based on their energy barrier heights and the stability of the reactants and products. Results show that oxidation largely decreases the ring-opening energy barrier for both stereoisomers, even though the process is forecast as too slow to be competitive. Conversely, one-electron reduction dramatically facilitates the ring opening of the azetidine heterocycle. Considering the overall quantum-chemistry findings, N,N-dimethylaniline is proposed as an efficient photosensitizer to trigger the photoinduced cycloreversion of the DNA lesion model.

scholarly journals The Equally Important Role of Adenine Derivatives to That of Pyrimidine Derivatives in Near-0 eV Electron-Induced DNA Lesions

ChemPhysChem ◽  
2016 ◽  
Vol 17 (11) ◽  
pp. 1669-1677 ◽  
Author(s):  
Shoushan Wang ◽  
Peiwen Zhao ◽  
Changzhe Zhang ◽  
Yuxiang Bu
Keyword(s):  
Dna Lesions ◽  
Pyrimidine Derivatives ◽  
Adenine Derivatives

Role of (H2O)n (n = 2–3) Clusters on the HO2 + O3 Reaction: A Theoretical Study

2015 ◽  
Vol 120 (8) ◽  
pp. 1560-1568 ◽  
Author(s):  
Luís P. Viegas ◽  
António J. C. Varandas
Keyword(s):  
Theoretical Study

Theoretical study on the role of cooperative solvent molecules in the neutral hydrolysis of ketene

2010 ◽  
Vol 127 (5-6) ◽  
pp. 493-506 ◽  
Author(s):  
Xiao-Peng Wu ◽  
Xi-Guang Wei ◽  
Xiao-Ming Sun ◽  
Yi Ren ◽  
Ning-Bew Wong ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Solvent Molecules ◽  
Hydrolysis Of

The Role of Platinum-DNA Lesions in the Inhibition of DNA Replication

1991 ◽  
pp. 181-193
Author(s):  
N. P. Johnson ◽  
J. L. Butour ◽  
C. Cayrol ◽  
S. Cros ◽  
M. Defais ◽  
...  
Keyword(s):  
Dna Replication ◽  
Dna Lesions

General promoting effect of polydopamine on supported noble metal catalysts

2017 ◽  
Vol 5 (39) ◽  
pp. 20789-20796 ◽  
Author(s):  
Mingwei Zhang ◽  
Guozhu Li ◽  
Xiaoqing Sun ◽  
Yujiao Jiang ◽  
Xiangwen Zhang
Keyword(s):  
Noble Metal ◽  
Theoretical Study ◽  
Metal Catalysts ◽  
Promoting Effect ◽  
Noble Metal Catalysts

A joint experimental–theoretical study has been conducted to investigate the role of polydopamine as an interface facilitator for supported noble metal catalysts.

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