Judul: Khasiat Antihiperurisemia Ekstrak Kulit Batang Mahoni (Swietenia macrophylla King) pada Tikus Putih Galur Sprague Dawley
Abstrak: Mahogany bark is wood industrial waste, contains flavonoid compound supposedly as antihyperurisemic agent. However, study concerning antihyperuricemic potential of mahogany bark has not been done until now. The aim of this study was to investigate the potent of mahogany bark (Swietenia macrophylla King ) extracts on serum uric acid levels in hyperuricemic rats. Thirty-three rats were divided into 5 groups of: normal, hiperurisemia (HU), allopurinol (HU I), aqueous extract (HU II), and methanol extracts (HU III). Hyperuricemic condition was induced by oral administration of 25 g/KgBW chicken liver juice with sodium carboxyl methylcellulose 0.5% mixture in rats every day for 4 weeks. This was followed by oral administration of both aqueous extract and methanol extract at 500 mg/KgBW day for 7 days. Serum uric acid levels was determined by dichlorohydroxybenzene sulfonic acid (DHBS) method on 514 nm. The induction of hyperuricemia was able to increase the serum uric acid levels 36.83%. Aqueous extract and methanol extract reduced uric acid concentration 24.22% and 21.02%, respectively. Therefore, both of the extracts have a similar antihyperuricemic effect
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Judul: Penghambatan Peroksidasi Lipid oleh Ekstrak Kulit Batang Mahoni (Swietenia macrophylla King) pada Tikus Hiperurisemia
Abstrak: Increased blood uric acid (hyperuricemia) has been reported in the increased of lipid peroxidation. To overcome lipid peroxide formed, natural antioxidant compounds could be used, one of them is mahony bark extract. The purposes of this research are to analyze lipid peroxidation level and to determine the effect of mahony bark extract on blood lipid peroxide concentration in hyperuricemic rats. A total of 33 rats divided into 5 groups consist of normal control, hyperuricemic control (HU I), allopurinol (HU II, 3.3 mg/Kg BB), HU and water extract (HU III, 500 mg/Kg BB), and HU and methanol extract (HU IV, 500 mg/Kg BB). Hyperuricemia was induced by chicken liver juice fed in 28 days, thus, extract were given everyday in 7 days after, furthermore experiment was done in 35 days. Serum lipid peroxide concentration was analyzed in day-0, 14, 21, 28, and 35 using spectrophotometry method at 532 nm. The result of this research showed that average lipid peroxide concentration of all rats before experiment is 0.586±0.177 nmol/mL. Hyperuricemic induction had increased lipid peroxide concentration up to 11.23%. There was an increased of 11.41% after supplementation of allopurinol, on the contrary water extract could decrease blood lipid peroxide concentration over 26.86% (p= 0.006).
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Judul: Gelombang soliter internal pada lapisan atmosfir yang memiliki perubahan kecepatan angin yang cepat
Abstrak: Gelombang internal adalah suatu gelombang yang terjadi di dalam suatu fluida. Gelombang ini muncul karena adanya perubahan rapat massa di setiap lapisan di dalam fluida. Salah satu gelombang internal yang ditemui di lapisan atmosfir adalah gelombang soliter internal, seperti yang terjadi pada fenomena "Morning glory" di Australia. Pada fenomena "Morning glory" terjadi penurunan tekanan hingga beberapa millibar. Tulisan ini membahas perambatan gelombang soliter internal pada lapisan atmosfir. Lapisan atmosfir yang ditinjau memiliki suatu lapisan dimana kecepatan angin dan rapat massanya berubah secara cepat, sedangkan lapisan lainnya relatif konstan. Persamaan gerak gelombang diturunkan berdasarkan persamaan kekontinuan dan persamaan momentum. Sedangkan metode yang digunakan adalah metode asimtotik. Solusi persamaan gerak dimisalkan dalam bentuk gelombang berjalan, dan bentuknya berupa fungsi rasional. Sebagai contoh, diberikan suatu studi kasus dimana pada suatu lapisan kecepatan angin dan rapat massanya berupa fungsi linear, sedangkan lapisan lainnya konstan.
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