Authors:G. Rezaei Behbehani, A. A. Saboury, A. Taherkhani, L. Barzegar, and A. Mollaagazade
Rezaei Behbehani , G , Divsalar , A , Saboury , AA , Faridbod , F , Ganjali , MR . A high performance method for thermodynamicstudy on the binding of human serum albumin with erbium chloride . J Therm Anal Calorim . 2009 ; 96 : 663 – 668
Authors:D. Živković, I. Katayama, A. Kostov, and Ž. Živković
The results of comparative thermodynamic study of GaSb-Sn system are presented in this paper. Calorimetric measurements according
to Oelsen's method and EMF measurements with zirconia as solid electrolyte were used for experimental investigation, while
Chou's general solution model, Toop, Kohler and Muggianu methods were used for predicting thermodynamic characteristics in
this system. Also, phase diagram of this quasibinary system, determined by DTA and optical microscopy, is presented.
Non-isothermal dehydration of copper chloride dihydrate and nickel chloride hexahydrate were studied by using TG, DTG, DTA
and DSC measurements. The copper chloride salt loses its two water molecules in one step while nickel chloride salt dehydrates
in three consecutive steps. The first two steps involve the loss of 4 water molecules in two overlapped steps while the third
step involves the dehydration of the dihydrate salt to give the anhydrous NiCl2.
Activation energies (ΔE) and the frequency factor (A) were calculated from DTG and DTA results. We have also calculated the different thermodynamic parameters, e.g. enthalpy
change (ΔH), heat capacity (Cp) and the entropy change (ΔS) from DSC measurements for both reactants.
The isothermal rehydration of the completely dehydrated salts was studied in air and under saturated vapour pressure of water.
Anhydrous nickel chloride was found to rehydrate in three consecutive steps while the copper salt rehydrated in one step.
A thermodynamic study of the influence of the thermal treatments (annealing), below the glass transition temperature, on the
thermal behavior and enthalpy of maltitol glass was carried out by differential scanning calorimetry (DSC). An enthalpic effect
(exothermal) produced by the isothermal treatment of the quenched glass was found and measured.
The origin of the thermal effect was assigned to a physicochemical transformation of molecular associations in the solid (glass).
To achieve a correct description of the thermodynamic functions of glasses, another parameter, in addition to T and P, is introduced, namely the degree of advance of the above mentioned transformation.
A thermodynamic study on the interaction of bovine carbonic anhydrase II (CAII) with nickel ions was performed by using isothermal
titration calorimetry (ITC) at 27 °C in Tris buffer solution at pH = 7.5. The enthalpies of Ni2+ + CAII interaction are reported and analysed in terms of the new solvation theory. It was indicated that there are three
identical and non-cooperative sites for Ni2+. The binding of a nickle ion is exothermic with dissociation equilibrium constants of 81.306 and 99.126 μM at 27°C and 37°C,
respectively. The binding of nickel ions can cause some changes in the stability of the enzyme at low and high Ni2+ concentrations.
The urobilinogenic chlorophyll catabolites are secondary metabolites formed by the biodegradation of chlorophylls. The thermodynamic study of the urobilinogenic chlorophyll catabolites from autumnal leaves extract of Parrotia persica and Hamamelis virginiana was done using reversed-phase liquid chromatography on the C4 and C8 analytical columns with acidified water-methanol mobile phase in combination with ultraviolet detection and electrospray ionization mass spectrometry. The presence of the urobilinogenic chlorophyll catabolites was detected by their characteristic ultraviolet absorption and their molecular mass. The retention behaviors of the two urobilinogenic chlorophyll catabolite isomers over a temperature range of 278–318 K were investigated. The retention time data permitted the construction of the van't Hoff plots. The stationary phase composition influences the thermodynamics of the retention of the urobilinogenic chlorophyll catabolites. The study presented can find the application in the separation of the urobilinogenic chlorophyll catabolites in autumnal leaves extracts.
Authors:M. E. Kassem, A. M. El-Khatib, E. A. Ammar, and M. M. Denton
Thermodynamic studies of (LixK1−x)2SO4, LKS, mixed crystals have been made in the concentration range (x=0.1, 0.2, ...,x=0.5). The thermal behaviour has been investigated by differential thermal analysis, DTA, and differential scanning calorimeter, DSC, in the vicinity of high temperature phases. Also, the effect of the thermal neutron irradiations on the thermal properties of mixed crystals was studied. The results showed a change in the transition temperatureTc, as well as the value of specific heatCp at transition temperature, due to the change of stoichiometric ratio and radiation doses. The change of enthalpy and entropy of mixed crystals have been estimated numerically.