Hepatoprotektivno djelovanje ekstrakta biljke Calotropis gigantea na oštećenje jetre štakora tetraklormetanom

Ethanolic extract (50 %) of stems of Calotropis gigantea R. Br. (Asclepiadaceae) at doses of 250 and 500 mg kg1 were studied for hepatoprotective activity in male Wistar rats with liver damage induced using carbon tetrachloride, 2 mL kg-1 twice a week. The protective effect of C. gigantea extract was compared with the standard drug silymarin. Various biochemical parameters such as aspartate amino transferase (AST), alanine amino transferase (ALT), glutathione (GSH), lipid peroxide (LPO), superoxidedismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were evaluated. The results revealed that the C. gigantea extract significantly decreased AST, ALT (p < 0.001) and lipid peroxide (p < 0.01) levels. The antioxidant parameters GSH, GPx, SOD and catalase levels were increased considerably compared to the levels in groups treated with carbon tetrachloride onlyEtanolni ekstrakt (50 %) stabljika biljke Calotropis gigantea R. Br. (Asclepiadaceae) u dozi 250 i 500 mg kg1 testiran je na hepatoprotektivno djelovanje oštećenje jetre mužjaka Wistar štakora inducirano tetraklormetanom, 2 mL kg1 dva puta tjedno. Zaštitni učinak ekstrakta biljke C. gigantea uspoređivan je sa standarnim lijekom silimarinom. Evaluirani su različiti biokemijski parametri kao što su aspartat amino transferaza (AST), alanin amino transferaza (ALT), glutation (GSH), lipidni peroksidi (LPO), superoksiddismutaza (SOD), glutation peroksidaze (GPx) i katalaza (CAT). Rezultati ukazuju da ekstrakt biljke C. gigantea značajno smanjuje koncentracije AST, ALT (p < 0.001) i lipidnih peroksida (p < 0.01). Koncentracije antioksidativnih parametara GSH, GPx, SOD i katalaze bile su značajno povišene u usporedbi sa skupinom tretiranom samo tetraklormetanom

Popularity-aware content caching for distributed wireless helper nodes

Content caching enables end users to obtain contents in a short time. To further reduce the time to access a mobile wireless network, we consider a device-to-device communication scenario where contents are distributed and users may obtain contents directly from neighbors instead of accessing the base station. For maximizing the cache hit rate per unit of bandwidth consumed, we derive a theoretical model based on the probability distribution of content popularity. To make the problem tractable, we propose a popularity-aware content caching mechanism using the modified weighted Zipf distribution. Through our simulation with a real YouTube trace, the proposed algorithm is compared with the existing well-known least-recently-used algorithm in terms of the achieved hit rate, caching time, cache eviction rate, and consumed bandwidth. The results show that our approach is able to achieve near-optimal performances and at the same time approximate the optimal cache time a cached content resides at the device