COMPLEX COMPOUNDS BASED ON PINOSTROBIN OXIME

The article studied the structural features of solid dispersions of pinostrobin oxime with arabinogalactan, disodium salt of glycyrrhizic acid, polyvinylpyrrolidone and basic magnesium carbonate obtained by mechanochemical treatment. The obtained complexes of pinostrobin oxime with arabinogalactan, disodium salt of glycyrrhizic acid, polyvinylpyrrolidone, and basic magnesium carbonate have increased water solubility in comparison with the initial pinostrobin oxime. The thermal effects of pinostrobin oxime and its complex compounds have been studied by differential scanning calorimetry. At the same time, on the DSC-curve, the melting peak of solid dispersions of pinostrobin oxime with disodium salt of glycyrrhizated acid and pinostrobin oxime with arabinogalactan is not displayed, which is associated with the intermolecular interaction of the components of the complex, where the molecule of pinostrobin oxime forms a bond with a complexformation agent during mechanochemical treatment. The complex of pinostrobin oxime with magnesium carbonate is not formed, as evidenced by the thermal curve, where the melting of the sample begins at 182 °C, and complete destruction occurs at a temperature of 782 °C, which is similar to the melting peak of the initial pinostrobin oxime. The results of studying intermolecular bonds in complexes of pinostrobin oxime by the method of NMR-relaxation indicate that the times of spin-lattice and spin-spin relaxation are very sensitive to intermolecular interaction and to the diffusion mobility of molecules.

Insight into the Role of a Isophthalic Dihydrazide Derivative Containing Piperonylic Acid in Poly(L-lactide) Nucleation: Thermal Performances and Mechanical Properties

This work was aimed at synthesizing the N, N -isophthalic bis(piperonylic acid) dihydrazide (PAID) to be as a new crystallization accelerator for poly(L-lactide) (PLLA), and a detailed investigations of the non-isothermal crystallization, melting behavior, thermal decomposition behavior and mechanical properties of PLLA nucleated by PAID were performed applying differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and electronic tensile tester. The melt-crystallization proved that the PAID could act as a heterogeneous nucleating agent to significantly promote the crystallization in cooling, even the crystallization was still able to be accelerated upon the fast cooling at 50 oC/min. The final melt temperature was another crucial factor for PLLA�s melt crystallization, and when the final melt temperature was 170 oC, the onset crystallization temperature and melt-crystallization enthalpy was almost up to 150 oC and 56.8 J/g upon cooling of 1 oC/min, respectively. Furthermore, the chemical nucleation was proposed to be the nucleation mechanism of PAID for PLLA via the preliminary theoretical calculation. For the cold-crystallization, the addition of PAID exhibited an inhibition for the crystallization of PLLA, but the total crystallization process depended on the heating rate and PAID concentration. The single melting peak after cooling of 1 oC/min indicated that the crystallization had been thoroughly completed in cooling. Additionally, the single melting peak with different locations after full crystallization resulted from the different crystallization temperatures. A comparison in the onset decomposition temperature implied that the presence of PAID only slightly decreased the thermal stability of PLLA. The mechanical testing showed that, in contrast with the elongation at break, the existence of PAID enhanced the tensile strength of PLLA.

Differential scanning calorimetry of cocoa butter and chocolate glaze

Nowadays there is a wide market for cocoa butter equivalents, substitutes and improvers for the confectionery and dairy industries. An urgent task is the development of operational instrumental methods for cocoa butter and its substitutes quality control. Thermophysical parameters are among the most important characteristics of the fat phase for the food technology. Differential scanning calorimetry (DSC) is becoming one of the most promising methods for analytical control of fat and oil products. Thermophysical data (temperatures of the maximums of endothermic peaks and their areas) for cocoa butter and chocolate glaze typical samples applied at dairy processing enterprises of the Central black soil region for the production of chocolate glazed curd bars were obtained in the work performed with its help. DSC data were compared with chromatographic data on triglyceride composition of the fat phase of cocoa butter, cocoa butter equivalents, lauric and non-lauric substitutes, and POP and SOS cocoa butter improvers. It was shown that the DSC method can control the quality of cocoa butter and chocolate glaze, identify chocolate products of different origin and triglyceride composition. Melting thermograms obtained by DSC are highly sensitive to the fat phase triglyceride composition. DSC allows reliable identification of samples of cocoa butter and glaze by melting curves in the temperature range from -100 to +50 ° C. It was found that the main melting peak of cocoa butter and its substitutes, due to the presence of a certain set of triglycerides, is observed in the temperature range from -5 to +30 °C. When examining glazes, the melting peak changes: it bifurcates, expands or narrows. Additional application of computer separation of the unseparated peaks superposition on the DSC melting curves increases the information content of the method and improves the reliability of the fat phase identification. The DSC method is characterized by sample preparation simplicity, has good reproducibility and other metrological characteristics and can be an independent method for fat and oil products identifying and quality control..

Skin Pigmentation Differences between Mongolian, Korean, and Uzbekistan Ancient Human DNA Samples

Background. This study reports the use of real-time PCR to identify the SNP rs1545397 in the intron region on the OCA2 gene from ancient and degraded DNA isolated from ancient human bones from Mongolia, Korea, and Uzbekistan. This SNP is a marker for skin pigmentation. LightCycler-based probes (HybProbes) were designed. A LightCycler (version 2.0) system was used for the real-time PCR. Results. The results of the real-time PCRs of three different genotypes of SNP rs1545397 were compared with those of the direct sequencing. Melting curve analysis was used for genotype determination. Three genotypes were distinguished: the homozygous T (T/T) SNP type formed a distinct melting peak at 53.3±0.14°C, the homozygous A (A/A) SNP type formed a distinct melting peak at 57.8±0.12°C, and the heterozygous A/T SNP type formed two distinct melting peaks at 53.3±0.17°C and 57.8±0.15°C. Mongolian aDNA samples tested in this study carried all three types of the SNP (A/T, A/A, and T/T) with no distinctly predominant type observed. In contrast, Korean aDNA samples carried the Asian genotype (T/T), while the Uzbekistan aDNA samples carried the European genotype (A/A) more often than the Asian genotype (T/T). Conclusions. Human Mongolian aDNA samples had A/T, A/A, and T/T SNP rs1545397 with no distinct predominant genotype. When combined with the archeological and aDNA studies of other coupling morphologies with aDNA, our results infer that Mongolia’s prehistoric population had considerable heterogeneity of skin color and morphological traits and that in the Neolithic period, a Eurasian or mixed population inhabited the western part of Mongolia.

Stereocomplex formation in injection-molded poly(L-lactic acid)/poly(D-lactic acid) blends

Poly(L-lactic acid)/poly(D-lactic acid) (PLLA/PDLA) blends were prepared by hand mixing, followed by injection molding at 210°C to produce tensile specimens. Thermal properties, crystalline structure, and mechanical properties were measured by differential scanning calorimetry (DSC), thermogravimetric analysis, wide-angle X-ray diffraction (XRD), and tensile testing. From the DSC tests of blends ranging from 10% to 30% PDLA in PLLA, the PDLA melting peak was absent and was replaced by a stereocomplex melting peak at 210°C, which was ~50°C higher than that for neat PLLA or PDLA. The reverse blending of PLLA into PDLA showed a similar behavior. Surprisingly, three melting peaks (for PLLA, PDLA, and the complex crystal) appeared in the 1:1 PLLA:PDLA pellet blends. However, the PLLA and PDLA powders (ground to less than 200 μm) and hand mixed, prior to injection molding, showed only small amounts of homocrystals and much higher fractions of stereocomplex crystals (18–44%). Compared to the hand mixed un-ground pellets, molded specimens from the PLLA and PDLA powders also exhibited higher tensile strengths (33–48 MPa) and moduli (1100–1250 MPa). Moreover, the stereocomplex formation was found to enhance the thermal stability compared with those of the pure PLLA and PDLA.