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- Author or Editor: N. Stojanović x
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The fatty acid composition and trans fatty acid (TFA) content of Serbian shortenings were determined by capillary gas chromatography-mass spectrometry. The saturated, cis-monounsaturated and polyunsaturated fatty acid contents were within the ranges of 16.0–89.0, 4.9–41.9 and 0.0–23.2% of total fatty acids, respectively. Among the saturated fatty acids, palmitic acid (4.8–48.7%) was dominant and its higher amount indicates that palm oil was the major contributor in the shortening manufacturing. The content of total trans fatty acids ranged from 0.0% to 48.7% of total fatty acids and the mean was 27.4%. Trans 18:1 isomers were the major group of TFA present in analysed samples, representing 94.2% of total trans isomers. The content of all 18:2 trans isomers ranged from 0.0% to 3.6% of total fatty acids. Among thirty-four analysed samples only six contained low level of TFA (0.0–3.1%) while the rest contained very high amounts of TFA (10.2–48.7%) which clearly indicate that partially hydrogenated vegetable oils are still the major raw materials used in the production of shortenings in Serbia.
This study aimed to assess the role of H2S in homocysteine-induced cardiodynamic effects in the isolated rat heart. The hearts were retrogradely perfused according to the Langendorff technique. The maximum and minimum rates of pressure in the left ventricle (dp/dt max, dp/dt min), systolic and diastolic left ventricular pressures (SLVP, DLVP), heart rate (HR), and coronary flow (CF) were measured. A spectrophotometrical method was used to measure the following oxidative stress markers: index of lipid peroxidation (thiobarbituric acid reactive substances, TBARS), nitrite level (NO2 −), superoxide anion radicals (O2 •−), and hydrogen peroxide (H2O2) concentrations. The administration of 10 µmol/l DL-homocysteine (DL-Hcy) alone decreased dp/dt max, SLVP, and CF but did not change any oxidative stress parameters. The administration of 10 µmol/l DL-propargylglycine (DL-PAG) decreased all cardiodynamic parameters and increased the concentration of O2 •−. The co-administration of DL-Hcy and DL-PAG induced a significant decrease in all estimated cardiodynamic parameters and decreased the concentration of NO2 − and O2 •− but increased the levels of TBARS and H2O2. Homocysteine shows a lower pro-oxidative effect in the presence of hydrogen sulfide (H2S), which indicates a potential anti-oxidative capacity of H2S.
Thermal analysis of binary liquid crystalline mixtures
System of bent core and calamitic molecules
Abstract
Two series of binary mixtures composed of bent shaped and rod like molecules are reported. The first star shaped bent core molecules were synthesized and used as a component of binary mixtures. The chiral rod like compounds having commensurable length with the arms of the bent core compounds have been chosen for these mixtures. The resulted compositions show various thermotropic liquid crystalline phases that are characteristic to both types of liquid crystalline materials. In case of mixing the rod like molecules to the bent core compound the B2, B7 and induced B1 phases have been observed. While using the star-shaped bent core and chiral rod like compounds in mixture, the paraelectric smectic A, ferroelectric smectic C* and orthogonal hexatic smectic B phases were preferred. The appearing mesophases were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction methods.
