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methods to monitor in MM patients in any stages. Differential scanning calorimetry (DSC) is unsurpassed for understanding the stability of biological systems. DSC directly measures the stability and unfolding of a protein, lipid, or nucleic acid

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Journal of Thermal Analysis and Calorimetry
Authors: Jiawu Gao, Lin Li, Yanping Deng, Zongming Gao, Changhua Xu, and Mingxi Zhang

Abstract  

A new method for determining the degree of conversion of gelation (αgel) and gel time (t gel) at gel point using a single technology, DSC, is discussed in this work. Four kinds of thermoset resins are evaluated. It is found that the mutation points of reduced reaction rate (V r) vs. reaction conversion (α) curves, corresponding with the changes of reaction mechanism, represents the gelation of the reaction. The α at the mutation point is defined as αgel. From isothermal DSC curves, the point at αgel is defined ast gel. Traditional techniques (ASTM D3532 and DSC method) are also used to determine αgel andt gel in order to demonstrate this new method. We have found that the results obtained from this new method are very consistent with the results obtained from traditional methods.

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A bioluminescent derivative of Bacillus subtilis containing a plasmid encoding a luxAB fusion under control of a vegetative promoter and gives bioluminescence upon addition of an exogenous long-chain aldehyde has been used as test organism. Its spore populations have been produced and their heat- and radiation survival curves established. Heat-sensitization effect of pre-irradiation of spores was proven not only by colony counting but also with differential scanning calorimetry. Under a linearly programmed temperature increase, the heat destruction of spores surviving 2.5 kGy gamma irradiation resulted in at a few centigrade lower temperature than that of untreated spores. Heat denaturation endotherms in the DSC-thermogram of irradiated spores were shifted to lower temperatures as well. Comparative turbidimetric, luminometric and phase-contrast microscopic studies of untreated, heat-treated and irradiated spore populations showed that the kinetics of germination and the light emission during germination of radiation-inactivated spores were the same as those of untreated spores, revealing that the pre-formed luciferase enzyme packaged into the spores during sporulation remained intact after an irradiation dose causing 90% decrease in number of colony forming spores. Therefore, in contrast to heat-treated spores, the initial bioluminescence reading upon germination of irradiated spores does not reflect the viable count of their population.

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Journal of Thermal Analysis and Calorimetry
Authors: Mariam Khvedelidze, Tamaz Mdzinarashvili, Tamar Partskhaladze, Noha Nafee, Ulrich Schaefer, Claus-Michael Lehr, and Marc Schneider

Abstract  

The calorimetric investigation of non-coated and chitosan-coated PLGA nanoparticles (NP) shows that at initial temperatures of heating particle swelling takes place what results in an internal architectural change at lower than physiological temperature. It has shown that the temperature of NP tightness perturbing depends on solvent polarity: as more polar is the solvent more stable are particles. The break of existing bonds in NP shell is accompanied with heat absorption peak which undergoes significant changes depending on heating rate. In the wide pH 2–8 interval in transition temperature no changes occurred. The obtained results show that such NP could be used in acidic area for drug transfer, which gives possibility to take medicine orally. It was shown that DNA attaches only to chitosan-coated NP. The optimal ratio for DNA loading onto the NP was found to be 7:1 (WNP/WDNA).

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the glass/crystal transformation in a binary Se 90 In 10 glass using differential scanning calorimetry (DSC) technique. Theoretical basis DSC technique is widely used for study of the kinetics of glass

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. Differential scanning calorimetry (DSC) is one of the well established techniques in detection of incompatibility in drug/excipient [ 1 – 5 ]. DSC has now become first choice in pharmaceutical industry for compatibility study. Isothermal stability study (ISS

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calorimetry (DSC) data is analyzed with the help of the isoconversional methods of Kissinger–Akahira–Sunose (KAS) and Friedman. These isoconversional methods are extensively used for analysing non-isothermal decomposition, crystallization and degradation

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Journal of Thermal Analysis and Calorimetry
Authors: Jorge López-Beceiro, José Pascual-Cosp, Ramón Artiaga, Javier Tarrío-Saavedra, and Salvador Naya

the decomposition processes are still not clear. In this study, a synthetic hydrated potassium aluminum sulfate is investigated by simultaneous TG-differential scanning calorimetry (DSC), attached to a Fourier transform infrared (FTIR) spectrometer

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Introduction Differential scanning calorimetry (DSC) is sensitive to the heat changes associated with thermally driven phase transitions and is thus particularly suited to physical form characterisation of pharmaceuticals

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