scholarly journals Microscale Mechanical‐Chemical Modeling of Granular Salt: Insights for Creep

Author(s):  
Mengsu Hu ◽  
Carl I. Steefel ◽  
Jonny Rutqvist
Keyword(s):  
2021 ◽  
Vol 172 ◽  
pp. 145-157
Author(s):  
Haoran Xu ◽  
Jingru Cheng ◽  
Zhihong Zhao ◽  
Tianyi Lin ◽  
Guihong Liu ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2248
Author(s):  
Lukáš Petera ◽  
Klaudia Mrazikova ◽  
Lukas Nejdl ◽  
Kristyna Zemankova ◽  
Marketa Vaculovicova ◽  
...  

Synthesis of RNA nucleobases from formamide is one of the recurring topics of prebiotic chemistry research. Earlier reports suggest that thymine, the substitute for uracil in DNA, may also be synthesized from formamide in the presence of catalysts enabling conversion of formamide to formaldehyde. In the current paper, we show that to a lesser extent conversion of uracil to thymine may occur even in the absence of catalysts. This is enabled by the presence of formic acid in the reaction mixture that forms as the hydrolysis product of formamide. Under the reaction conditions of our study, the disproportionation of formic acid may produce formaldehyde that hydroxymethylates uracil in the first step of the conversion process. The experiments are supplemented by quantum chemical modeling of the reaction pathway, supporting the plausibility of the mechanism suggested by Saladino and coworkers.


Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 135
Author(s):  
Pattan-Siddappa Ganesh ◽  
Sang-Youn Kim ◽  
Savas Kaya ◽  
Rajae Salim ◽  
Ganesh Shimoga ◽  
...  

To develop an electrochemical sensor for electroactive molecules, the choice and prediction of redox reactive sites of the modifier play a critical role in establishing the sensing mediating mechanism. Therefore, to understand the mediating mechanism of the modifier, we used advanced density functional theory (DFT)-based quantum chemical modeling. A carbon paste electrode (CPE) was modified with electropolymerization of brilliant blue, later employed for the detection of paracetamol (PA) and folic acid (FA). PA is an analgesic, anti-inflammatory and antipyretic prescription commonly used in medical fields, and overdose or prolonged use may harm the liver and kidney. The deficiency of FA associated with neural tube defects (NTDs) and therefore the quantification of FA are very essential to prevent the problems associated with congenital deformities of the spinal column, skull and brain of the fetus in pregnant women. Hence, an electrochemical sensor based on a polymerized brilliant blue-modified carbon paste working electrode (BRB/CPE) was fabricated for the quantification of PA and FA in physiological pH. The real analytical applicability of the proposed sensor was judged by employing it in analysis of a pharmaceutical sample, and good recovery results were obtained. The potential excipients do not have a significant contribution to the electro-oxidation of PA at BRB/CPE, which makes it a promising electrochemical sensing platform. The real analytical applicability of the proposed method is valid for pharmaceutical analysis in the presence of possible excipients. The prediction of redox reactive sites of the modifier by advanced quantum chemical modeling-based DFT may lay a new foundation for researchers to establish the modifier–analyte interaction mechanisms.


MRS Bulletin ◽  
1997 ◽  
Vol 22 (6) ◽  
pp. 46-51 ◽  
Author(s):  
W.R. Salaneck ◽  
J.L. Brédas

Since the discovery of high electrical conductivity in doped polyacetylene in 1977, π-conjugated polymers have emerged as viable semiconducting electronic materials for numerous applications. In the context of polymer electronic devices, one must understand the nature of the polymer surface's electronic structure and the interface with metals. For conjugated polymers, photoelectron spectroscopy—especially in connection with quantum-chemical modeling—provides a maximum amount of both chemical and electronic structural information in one (type of) measurement. Some details of the early stages of interface formation with metals on the surfaces of conjugated polymers and model molecular solids in connection with polymer-based light-emitting devices (LEDs) are outlined. Then a chosen set of issues is summarized in a band structure diagram for a polymer LED, based upon a “clean calcium electrode” on the clean surface of a thin film of poly(p-phenylene vinylene) (PPV). This diagram helps to point out the complexity of the systems involved in polymer LEDs. No such thing as “an ideal metal-on-polymer contact” exists. There is always some chemistry occurring at the interface.


2017 ◽  
Vol 66 (12) ◽  
pp. 2227-2233 ◽  
Author(s):  
V. B. Kobychev ◽  
V. B. Orel ◽  
D. V. Zankov ◽  
N. M. Vitkovskaya ◽  
B. A. Trofimov

2007 ◽  
Vol 119 (3) ◽  
pp. 418-424 ◽  
Author(s):  
Flavio Lumento ◽  
Vinicio Zanirato ◽  
Stefania Fusi ◽  
Elena Busi ◽  
Loredana Latterini ◽  
...  

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