RESUMEN
Hyperlipidemia is a condition of high lipid levels in the plasma and often linked with the deposition of lipid droplets in the aorta which initiate the progression of atherosclerosis. Atherosclerosis is a common cardiovascular disorder initiated by the formation of foams cells in the vascular wall which leads to turbulent blood flow, injury to the endothelial layer and subsequent vascular thrombosis. Since the early 1980’s, Golden-Syrian hamsters have been widely used as an animal model in the research of hyperlipidemia and atherosclerosis. The use of hamsters in the hyperlipidemic and atherosclerotic model is due to their lipoprotein profile that is closer to human setting, sensitive to high-fat high-cholesterol (HFHC) diet and a suitable rodent model. Atherosclerosis can be induced in hamsters through dietary challenge with HFHC diet. Over the decades, coconut oil (CNO) was commonly used as the source of fat in the diet design of high saturated fatty acids (SFA) composition. In this review, we summarized published literature with designs involving CNO plus cholesterol-induced hyperlipidemia, atherosclerosis or both. The factors that may influence the ability of CNO and cholesterol combination to induce hyperlipidemia such as the period of dietary intervention, hamster strains and the dietary amount were evaluated and summarized.
RESUMEN
This research was aimed to investigate the capability of a combined system of activated sludge and microfiltration processes with backflushing technique to reduce organic carbon and nitrogen compounds in hazardous landfill leachates. The experiments included acclimation, batch and continuous processes. The continuous process was conducted with a 24 hour HRT (Hydraulic Retention Time), and the SRT (Solid Retention Time) ranged from 16 to 36 days. The aeration basin volume was 5 L and the membrane filter used was a hollow fiber module made from polypropylene with pore size of 0.2 microm. The batch process (without membrane separation) achieved its steady state condition over a period of 33 days. The removal of COD, BOD5 and ammonia-N were 52.5%, 94.3% and 75.5%, respectively. The kinetic parameters obtained are as followed: the maximum specific growth rate constant (microm): 0.96/day and the saturation substrate constant (Ks): 16,445.32 mg/L. The high value of Ks indicated that the leachate was not easily biodegraded. The continuous process revealed that the system with SRT of 32 days was more stable than that of 16 and 24 days. The reduction of COD, BOD5 and ammonia-N were 31.3%; 66% and 98%, respectively. The stable flux was achieved around 5 L/m2 x hour.