Effect of ingestion of thermally oxidized sunflower oil on the fatty acid composition and antioxidant enzymes of rat liver and brain in development

BACKGROUND

The current study was undertaken to assess the effects of oxidized sunflower oil ingestion (obtained by heating at 98 degrees C with air insufflation during 48 h and incorporated at 5% in a fat-free diet) on liver and brain fatty acid composition, and some serum parameters and protective enzymes against peroxidation (glutathione peroxidase, glutathione reductase, catalase and glucose-6-phosphate dehydrogenase).

RESULTS

The main results show that the oxidized oil contains 262 mmol/kg of hydroperoxides, 5.7% of the esters are oxidized and 50.4% are polymerized. In the liver, we noticed that oxidized oil exercises a toxic effect as confirmed by the increase in the thiobarbituric acid reactive substance (TBARS) concentration. In the same way, we noticed that vitamin E exercises a favorable effect in the preservation against free radicals and lipid peroxidation; however, it cannot ensure this protection alone. In the liver, only glutathione peroxidase and glutathione reductase activities were positively correlated with the TBARS concentration. In the treated groups, we also noted changes in the fatty acid profiles of liver and brain homogenates, essentially by the appearance of trans fatty acid (18:1 trans) and an increase in arachidonic acid content.

Investigation of Er3+-Doped BaF2 Single Crystals for Infrared Emission and Photovoltaic Efficiency Enhancement

Er3+-doped BaF2 single crystals were investigated with two primary aims: first, to probe the infrared emissions from the 4I11/2 level (around 1.0 μm) under 1500-nm excitation and, second, to use the crystal to enhance the efficiency of silicon-based solar cells through upconversion mechanism. Upon excitation at 1500 nm, the upconversion emission spectrum of the Er3+-doped BaF2 single crystals, recorded in the range of 480-1080 nm, exhibited two well-structured visible bands at 538 and 650 nm, along with a strong near infrared emission at 971 nm. This strong 971-nm emission has an emission cross-section of approximately 0.23 × 10-20 cm2. As with any phenomenon inherent to energy transfer by upconversion, the 4I11/2 fluorescence decay exhibits a rise time followed by a long decay of approximately 15 ms and a positive optical gain from the low values of the population inversion coefficient, which could potentially give rise to laser emission from this level. When we place our crystal on a photovoltaic device illuminated by 1500-nm wavelength radiation, we record a photocurrent of 300 μA at an illumination power of 85 mW. This indicates that the Er3+-doped BaF2 crystal is highly suitable for significantly enhancing the efficiency of silicon-based solar cells.