Neutral and Negatively Charged Phosphate Modifications Altering Thermal Stability, Kinetics of Formation and Monovalent Ion Dependence of DNA G‐Quadruplexes

In this paper, magnesium oxychloride cement with stoichiometry 3Mg(OH)2∙MgCl2∙8H2O (MOC 3-1-8) was prepared and characterized. The phase composition and kinetics of formation were studied by X-ray diffraction (XRD) and Rietveld analysis of obtained diffractograms. The chemical composition was analyzed using X-ray fluorescence (XRF) and energy dispersive spectroscopy (EDS). Furthermore, scanning electron microscopy (SEM) was used to study morphology, and Fourier Transform Infrared (FT-IR) spectroscopy was also used for the analysis of the prepared sample. In addition, thermal stability was tested using simultaneous thermal analysis (STA) combined with mass spectroscopy (MS). The obtained data gave evidence of the fast formation of MOC 3-1-8, which started to precipitate rapidly. As the length of the time of ripening increased, the amount of MgO decreased, while the amount of MOC 3-1-8 increased. The fast formation of the MOC 3-1-8 phase at an ambient temperature is important for its application in the production of low-energy construction materials, which corresponds with the challenges of a sustainable building industry.

Download Full-text

Chemical Reactions between Thiocarbamylsulfenamides and Benzothiazylsulfenamides Leading to Cure Synergism

Rubber Chemistry and Technology ◽

10.5254/1.3535164 ◽

1977 ◽

Vol 50 (4) ◽

pp. 671-677 ◽

Cited By ~ 8

Author(s):

J. F. Krymowski ◽

R. D. Taylor

Keyword(s):

Thermal Stability ◽

Chemical Reactions ◽

Ionic Species ◽

High Thermal Stability ◽

High Cure ◽

Kinetics Of Formation ◽

Kinetics Of ◽

Thermal Stability Of

Abstract A combination of N-oxydiethylenethiocarbamyl-N′-oxydiethylenesulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, and sulfur was found to be synergistic in acceleration of vulcanization. The combination reacts at 142°C to form a number of new covalent compounds, most of which eventually decompose to ionic species. The types of compounds produced and the kinetics of formation of these intermediate compounds explain the good scorch delay, high cure efficiency, and high thermal stability of the vulcanizates when combinations of these two sulfenamides are used as vulcanization accelerators.

Download Full-text

Hydrogen Sorption Properties, Thermal Stability and Kinetics of Hydrogen Desorption From the Hydride Phase of The MgH2 of a Mechanical Alloys of Magnesium with Ti, Ni and Y

Фізика і хімія твердого тіла ◽

10.15330/pcss.21.1.167-175 ◽

2020 ◽

Vol 21 (1) ◽

pp. 167-175

Author(s):

O. G. Ershova ◽

V. D. Dobrovolsky ◽

Yu. M. Solonin

Keyword(s):

Thermal Stability ◽

Thermodynamic Stability ◽

Hydrogen Desorption ◽

Sorption Properties ◽

Hydrogen Sorption ◽

Hydride Phase ◽

Phase Content ◽

Stability Kinetics ◽

Kinetics Of

The mechanical alloys-composite MАs (Mg +10 % wt.Ti + 5 % wt.Y and Mg +10 % wt.Ni + 5 % wt.Y) were synthesized. The phase content, microstructure, the thermal stability, kinetics of hydrogen desorption from the MgH2 hydride phase of the obtained MAs were studiedby using XRD, SEM, TDS methods. It has been established that the addition of Ti + Y and Ni + Y to magnesium leads to significant improvement in the kinetics of hydrogen desorption from the MgH2 hydride phase, which is evidenced by a significant reduction (in 6 and 15 times)in the time of release of all hydrogen from MA1 and MA2, respectively. Due to, Ti, Ni,Y alloying, the decrease in the thermodynamic stability of MgH2 is not found.

Download Full-text

Stabilization of lead lithium iron tungstate with adding barium titanate

Journal of Materials Research ◽

10.1557/jmr.1997.0004 ◽

1997 ◽

Vol 12 (1) ◽

pp. 13-16

Author(s):

Chung-Hsin Lu ◽

Buh-Kuan Fang

Keyword(s):

Thermal Stability ◽

Barium Titanate ◽

Dielectric Permittivity ◽

Perovskite Phase ◽

Dielectric Constants ◽

Kinetics Of Formation ◽

Kinetics Of ◽

Complete Formation ◽

Thermal Stability Of ◽

Formation Phase

The kinetics of formation, phase stabilities, and dielectric constants of Pb(Li1/4Fe1/4W1/2)O3 and BaTiO3-added Pb(Li1/4Fe1/4W1/2)O3 have been compared. The addition of 2 mol% BaTiO3 in Pb(Li1/4Fe1/4W1/2)O3 was confirmed to promote the complete formation of the perovskite phase at 700 °C. Also, the thermal stability of the perovskite phase was significantly enhanced, which resulted in an increase of the dielectric permittivity.

Download Full-text

The Schiff bases of pyridoxal-5-phosphate and hydrazides of certain pyrazoles: Stability, kinetics of formation, and synthesis

Russian Journal of General Chemistry ◽

10.1134/s1070363217060093 ◽

2017 ◽

Vol 87 (6) ◽

pp. 1161-1166 ◽

Cited By ~ 2

Author(s):

G. A. Gamov ◽

V. V. Aleksandriiskii ◽

M. N. Zavalishin ◽

A. Yu. Khokhlova ◽

V. A. Sharnin

Keyword(s):

Schiff Bases ◽

Kinetics Of Formation ◽

Stability Kinetics ◽

Kinetics Of

Download Full-text

Kinetics of formation and thermal stability of Mg2(OH)3Cl·4H2O

10.1063/1.5132728 ◽

2019 ◽

Cited By ~ 2

Author(s):

Michal Lojka ◽

Adéla Jiříčková ◽

Anna-Marie Lauermannová ◽

Milena Pavlíková ◽

Zbyšek Pavlík ◽

...

Keyword(s):

Thermal Stability ◽

Kinetics Of Formation ◽

Kinetics Of ◽

Thermal Stability Of

Download Full-text

Thermal Stability Kinetics and Shelf Life Estimation of the Redox-Active Therapeutic and Mimic of Superoxide Dismutase Enzyme, Mn(III) meso-Tetrakis(N-ethylpyridinium-2-yl)porphyrin Chloride (MnTE-2-PyPCl5, BMX-010)

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/7003861 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Clarissa G. C. Maia ◽

Bárbara C. R. de Araujo ◽

Maria B. de Freitas-Marques ◽

Israel F. da Costa ◽

Maria Irene Yoshida ◽

...

Keyword(s):

Neural Network ◽

Thermal Stability ◽

Artificial Neural Network ◽

Superoxide Dismutase ◽

Solid State ◽

Shelf Life ◽

Expiration Date ◽

Redox Active ◽

Stability Kinetics ◽

Kinetics Of

Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride (MnTE-2-PyPCl5, BMX-010, and AEOL10113) is among the most studied superoxide dismutase (SOD) mimics and redox-active therapeutics, being currently tested as a drug candidate in a phase II clinical trial on atopic dermatitis and itch. The thermal stability of active pharmaceutical ingredients (API) is useful for estimating the expiration date and shelf life of pharmaceutical products under various storage and handling conditions. The thermal decomposition and kinetic parameters of MnTE-2-PyPCl5 were determined by thermogravimetry (TG) under nonisothermal and isothermal conditions. The first thermal degradation pathway affecting Mn-porphyrin structural integrity and, thus, activity and bioavailability was associated with loss of ethyl chloride via N-dealkylation reaction. The thermal stability kinetics of the N-dealkylation process leading to MnTE-2-PyPCl5 decomposition was investigated by using isoconversional models and artificial neural network. The new multilayer perceptron (MLP) artificial neural network approach allowed the simultaneous study of ten solid-state kinetic models and showed that MnTE-2-PyPCl5 degradation is better explained by a combination of various mechanisms, with major contributions from the contraction models R1 and R2. The calculated activation energy values from isothermal and nonisothermal data were about 90 kJ mol–1 on average and agreed with one another. According to the R1 modelling of the isothermal decomposition data, the estimated shelf life value for 10% decomposition ( t 90 % ) of MnTE-2-PyPCl5 at 25°C was approximately 17 years, which is consistent with the high solid-state stability of the compound. These results represent the first study on the solid-state decomposition kinetics of Mn(III) 2-N-alkylpyridylporphyrins, contributing to the development of this class of redox-active therapeutics and SOD mimics and providing supporting data to protocols on purification, handling, storage, formulation, expiration date, and general use of these compounds.

Download Full-text