scholarly journals Thermal behavior and thermodynamic parameters of some complexes of biologically active nucleic acid constituents

2021 ◽  
Vol 12 (2) ◽  
pp. 078-108
Author(s):  
M. S. Masoud ◽  
M. Sh. Ramadan ◽  
A. M. Sweyllam ◽  
A. M. Ramadan ◽  
M. H. Al-Saify
Keyword(s):  
Differential Scanning Calorimetry ◽  
Nucleic Acid ◽  
Thermogravimetric Analysis ◽  
Thermal Behavior ◽  
Thermodynamic Parameters ◽  
Biologically Active ◽  
Molecular Configuration ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Mechanism Of Decomposition

The thermal behavior of some complexes derived from biologically nucleic acid constituents has been studied applying differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Thermodynamic parameters, decompositions and thermal stabilities are calculated and explained. All the complexes gave exothermic peaks with -ve signs for change of entropy values, ΔS which indicate that the activated transition states are more ordered, i.e. in a less random molecular configuration than the reacting complexes. TGA gives the mechanism of decomposition.

scholarly journals Solvate Formation of Bis(demethoxy)curcumin: Screening and Characterization

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 407 ◽  
Author(s):  
Lina Yuan ◽  
Heike Lorenz
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Mass Loss ◽  
Storage Conditions ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
X Ray ◽  
Ambient Storage

Solvate formation of bis(demethoxy)curcumin (BDMC) was screened. Six solvates were obtained out of the nineteen solvents investigated. In the present work, three solvates, i.e., BDMC-tetrahydrofuran (THF), BDMC-1,4-dioxane (DIO) and BDMC-dimethyl sulfoxide (DMSO), were thoroughly studied. Their desolvation processes were characterized by temperature-resolved powder X-ray diffraction (TR-PXRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and hot-stage microscopy (HSM). TR-PXRD shows that all the solvates desolvate as the mother BDMC form and no new polymorph could be obtained. The stoichiometric ratio of solvates was calculated via the mass loss of solvents determined by TGA. The thermal stabilities of the solvates were obtained from DSC data and followed the order: BDMC-DMSO > -THF > -DIO. Moreover, stability performances at ambient storage conditions recorded by PXRD show that BDMC-DMSO was stable over three months.

scholarly journals Análisis térmico de mieles de Trigona (Tetragonisca) angustula de Norte de Santander, Colombia

Respuestas ◽  
2015 ◽  
Vol 20 (2) ◽  
pp. 135 ◽  
Author(s):  
Yaneth Cardona-Rodríguez ◽  
Diana Alexandra Torres-Sánchez ◽  
Wolfgang Hoffmann
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Thermal Behavior ◽  
Traditional Medicine ◽  
Stingless Bees ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Tetragonisca Angustula ◽  
Microbiological Properties

ResumenAntecedentes: Las mieles de abejas sin aguijón se utilizan principalmente con fines terapéuticos y medicinales; sin embargo, los estudios relacionados con estas mieles, son escasos y están enfocados en la determinación de algunas de sus características fisicoquímicas y microbianas. Objetivo: En este trabajo, se estudió el comportamiento térmico de mieles de Trigona (Tetragonisca) angustula, provenientes de tres lugares de Norte de Santander (Durania, Granja experimental Villa Marina y Los Patios), mediante calorimetría diferencial de barrido (DSC). Métodos: Se determinó el comportamiento térmico de las muestras de miel (~10 mg), utilizando un equipo SDT-Q600 de TA Instruments, que realiza simultáneamente Análisis Termogravimétrico y Calorimetría Diferencial de Barrido (TGA/DSC). Resultados: Se encontró que las muestras presentan 4 transiciones térmicas, independientemente del sitio de muestreo. Adicionalmente, se encontraron diferencias estadísticamente significativas en las entalpías de dichas transiciones. Conclusión: Las mieles producidas por la especie T. angustula presentan un comportamiento térmico característico, que permite diferenciarlas según su procedencia geográfica.Abstract Background: Honey of stingless bees is used in traditional medicine; nevertheless, studies related to these honeys are scarce and are focused in physicochemical and microbiological properties. Objective: We studied thermal behavior of honeys produced by Trigona (Tetragonisca) angustula, collected from three different places (Durania, Villa Marina and Los Patios), using Differential Scanning Calorimetry (DSC). Methods: We determined thermal behavior of honey samples (~10 mg), using a SDT-Q600, TA Instruments, simultaneous differential scanning calorimetry/thermogravimetric analysis (DSC/TGA). Results: T. angustula honeys exhibited four thermal transitions regardless sampling place. In addition, we found significant differences in the enthalpies of these transitions. Conclusion: Honey produced by T. angustula exhibited a characteristic thermal behavior, that will allow differentiate its geographical origin.Palabras Clave: Análisis térmico, Calorimetría Diferencial de Barrido (DSC), Miel, Trigona (Tetragonisca) angustula.

Thermal Stability of N-Heterocycle-Stabilized Iodanes – A Systematic Investigation

2019 ◽  
Author(s):  
Andreas Boelke ◽  
Yulia A. Vlasenko ◽  
Mekhman S. Yusubov ◽  
Boris Nachtsheim ◽  
Pavel Postnikov
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Systematic Investigation ◽  
Scanning Calorimetry ◽  
Thermal Stability Of

<p>The thermal stability of pseudocyclic and cyclic <i>N</i>-heterocycle-stabilized (hydroxy)aryl- and mesityl(aryl)-l<sup>3</sup>-iodanes (NHIs) through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is investigated. NHIs bearing <i>N</i>-heterocycles with a high N/C-ratio such as triazoles show among the lowest descomposition temperatures and the highest decomposition energies. A comparison of NHIs with known (pseudo)cyclic benziodoxolones is made and we further correlated their thermal stability with reactivity in a model oxygenation. </p>

scholarly journals Calorimetric techniques applied to the thermodynamic study of interactions between proteins and polysaccharides

2016 ◽  
Vol 46 (8) ◽  
pp. 1491-1497
Author(s):  
Monique Barreto Santos ◽  
Bernardo de Sá Costa ◽  
Edwin Elard Garcia Rojas
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermodynamic Parameters ◽  
Isothermal Titration Calorimetry ◽  
Thermal Energy ◽  
Titration Calorimetry ◽  
Biological Macromolecules ◽  
Valuable Insight ◽  
Scanning Calorimetry ◽  
Temperature Scanning ◽  
Insight Into

ABSTRACT: The interactions between biological macromolecules have been important for biotechnology, but further understanding is needed to maximize the utility of these interactions. Calorimetric techniques provide information regarding these interactions through the thermal energy that is produced or consumed during interactions. Notable techniques include differential scanning calorimetry, which generates a thermodynamic profile from temperature scanning, and isothermal titration calorimetry that provide the thermodynamic parameters directly related to the interaction. This review described how calorimetric techniques can be used to study interactions between proteins and polysaccharides, and provided valuable insight into the thermodynamics of their interaction.

scholarly journals Conversion of palm oil to new sulfur-based polymer by inverse vulcanization

2021 ◽  
Vol 287 ◽  
pp. 02014
Author(s):  
Amin Abbasi ◽  
Mohamed Mahmoud Nasef ◽  
Wan Zaireen Nisa Yahya ◽  
Muhammad Moniruzzaman
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Thermogravimetric Analysis ◽  
Palm Oil ◽  
Elemental Sulfur ◽  
Molten State ◽  
Scanning Calorimetry ◽  
Environmental Friendly ◽  
Sulfur Containing

The conversion of palm oil into a sulfur-based polymer by copolymerization with sulfur powder at its molten state is herein reported. The obtained sulfur-containing polymer was characterized using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to demonstrate the successful conversion. The disappearance of the peaks related to vinylic groups of oil together with the appearance of a peak representing C-H rocking vibrations in the vicinity of C-S bonds confirmed the copolymerization of sulfur with oil. TGA revealed that the polymers have thermal stability up to 230°C under nitrogen and the polymers leave 10% sulfur-rich ash. DSC proved that a small amount of elemental sulfur remained unreacted in the polymer, which showed amorphous and heavily crosslinked structure resembling thermosets. These copolymers are an environmental-friendly polymeric material promoting the utilization of the abundant sulfur while also adding value to palm oil.

Synthesis, characterization, and structures of zircona- and boracyclosiloxanes with ferrocenyl substituents

2002 ◽  
Vol 80 (11) ◽  
pp. 1469-1480 ◽  
Author(s):  
Karena Thieme ◽  
Sara C Bourke ◽  
Juan Zheng ◽  
Mark J MacLachlan ◽  
Fojan Zamanian ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
The Novel ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Multinuclear Nmr Spectroscopy

The novel zirconatetraferrocenylcyclotrisiloxane Cp2Zr(OSiFc2)2O (6), dizirconatetraferrocenylcyclotetrasiloxane [Cp2Zr(OSiFc2)O]2 (7), boratetraferrocenylcyclotrisiloxane (C6H5)B(OSiFc2)2O (8), and diboratetraferrocenylcyclotetrasiloxane [(C6H5)B(OSiFc2)O]2 (9) with ferrocenyl (Fc = Fe(η-C5H4)(η-C5H5)) substituents at silicon have been prepared from the reactions of Cp2Zr(NMe2)2 and PhBCl2 with diferrocenylsilanediol Fc2Si(OH)2 (3) and tetraferrocenyldisiloxanediol [Fc2SiOH]2O (5). The compounds were characterized by mass spectrometry, elemental analysis, UV–vis, IR, Raman, and multinuclear NMR spectroscopy, as well as single crystal X-ray diffraction. Thermogravimetric analysis and differential scanning calorimetry investigation of 6–9 showed that the cycles decompose before they can undergo any thermal ring-opening polymerization. In addition, no polymerization was detected in the presence of either KOSiMe3 or HOTf. The bulky ferrocenyl substituents on the Si atoms are likely to be at least partially responsible for the inability of these heterocycles to undergo ring-opening polymerization. Key words: heterocyclosiloxanes, ferrocenyl.

Effects of In and Sb addition on the thermal and wetting behavior of Sn-3.5Ag solder

2018 ◽  
Vol 30 (4) ◽  
pp. 233-240 ◽  
Author(s):  
Md Hasnine
Keyword(s):  
Differential Scanning Calorimetry ◽  
Melting Point ◽  
Thermal Behavior ◽  
Surface Finish ◽  
Design Methodology ◽  
Solder Alloys ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Cu Substrate ◽  
Free Solder

Purpose This paper aims to investigate the effect of In and Sb additions on the thermal behavior and wettability of Sn-3.5Ag-xIn-ySb (x = 0, 1.0 and 1.5 Wt.%, y = 0, 1.0, 1.4 and 2.1 Wt.%) solder alloys. Design/methodology/approach The thermal behavior of the Pb-free solder alloys was studied using differential scanning calorimetry. Wetting balance experiments were performed in accordance with the IPC standard, IPC-TM-650 and at a temperature of 260°C. Also, a solder spread test was performed on a Cu surface finish using the JIS-Z-3197 solderability standard. Findings It is shown that among the selected Sn-3.5Ag-xIn-ySb (x = 0, 1.0 and 1.5 Wt.%, y = 0, 1.0, 1.4 and 2.1 Wt.%) alloys, Sn-3.5Ag-1.5In-1Sb showed the lowest melting point and the lowest undercooling temperature. The best wettability was achieved when the In and Sb contents were approximately 1.5 and 1.0 Wt.%, respectively. The effect of the combined addition of In and Sb on solder spreadability on a Cu substrate was also demonstrated. Originality/value It was found that adding approximately 1.5 and 1.0 Wt.% of In and Sb, respectively, in Sn-3.5Ag solder provided the best wetting performance and improved the solder spreadability.

scholarly journals Thermal stability of Sn anode material with non-aqueous electrolytes in sodium-ion batteries

2018 ◽  
Vol 6 (41) ◽  
pp. 20383-20392 ◽  
Author(s):  
Yongho Lee ◽  
Hyojun Lim ◽  
Sang-Ok Kim ◽  
Hyung-Seok Kim ◽  
Ki Jae Kim ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Behavior ◽  
Anode Material ◽  
Sodium Ion ◽  
Aqueous Electrolytes ◽  
Sodium Ion Batteries ◽  
Scanning Calorimetry ◽  
Sn Anode ◽  
Thermal Stability Of

The thermal behavior of fully lithiated and sodiated Sn electrodes cycled in a MePF6 (Me = Li or Na)-based electrolyte was studied using differential scanning calorimetry (DSC).

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