Judul: Potensi Tepung Umbi Dioskorea (Dioscorea alata) untuk Mencegah Aterosklerosis pada Kelinci Percobaan
Abstrak: Recently, cardiovascular disease is one of the main causes of adult mortality in the world including in Indonesia. One of major risk factors of cardiovascular disease is hyperlipidemia. Prolonged hyperlipidemia accompanied by LDL oxidation is the first step of the development of atherosclerosis. Selection of food consumed is one way to reduce the risk of the development of atherosclerosis. Dioscorea alata (DA) tuber has potency to reduce the risk of atherosclerosis because it contains several functional compounds; anthocyanins, dietary fiber, and diosgenin. This contents lower the risk by antioxidation, antihyperlipidemia, and antiaggregation mechanisms. The objective of this research was to study the effect of administration of DA flour to inhibit atherosclerosis in laboratory rabbits. There were five specific objectives of the research ; (1) to determine the citric acid concentration and the duration of steam blanching which produce DA flour with the higest bioactive compounds, (2) to determine antioxidation and anti platelet aggregation effects of DA flour by in vitro test, (3) to examine the effects of DA flour administration on the activity of antioxidant enzymes in serum and kidney by in vivo test, 4) to examine the effect of DA flour administration on blood lipid profiles of the rabbits; and (5) to analyze the development of atherosclerosis plaques in aorta, and examine the morphologic change in rabbits kidney tissues. The results showed that 1% citric acid soaking and 10 minutes blanching produced DA flour with the highest anthocyanins and polyphenolic retention as high as 44.51% or 104.36 mg/100 g flour and 62.58% or 198.52 mg equivalent gallic acid/100 g flour, respectively. The flour had antioxidant capacity equal to 1300 mg trolox/100 g. Five or ten minutes steam blanching could reduce the activity of polyphenol oxidase enzyme, therefore retarded the oxidation process that degraded polyphenolic compound. These treatments were applied to produce DA flour which later formulated into rabbits ration. DA water extracts and flours were co-administrated with high cholesterol ration to 30 male New Zealand White rabbits for 60 days with the following ration groups; 1) basal ration as negative control (K0); 2) basal ration with 0.5% cholesterol as positive control (K1); 3) basal ration with 0.5% cholesterol and 1.8 g/100 g of freeze dried DA extract (KE1); 4) basal ration with 0.5% cholesterol and 3.6 g/100 g of freeze dried DA extract (KE2); 5) 15% DA flour in basal ration with 0.5% cholesterol (KT1); and 6) 30% DA flour in basal ration with 0.5% cholesterol (KT2). Experiment on antioxidatif stress effect of DA flour in rabbits showed that the level of SOD serum in rabbit co-administrated with DA flour to high cholesterol ration was significantly higher compared to those fed with cholesterol ration. 30% DA flour substitution into the ration, significantly maintained the level of SOD serum equal to that of administrated with basal ration. The other stress oxidative parameters; malondialdehyde (MDA) and glutathione peroxidase (GSHPx) activities showed no differences between treatments. The administration of high cholesterol ration increased total cholesterol 16 fold as compared to those administrated with basal ration, and increased cholesterol LDL, and triacylglycerol level significantly. Co-administration
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Judul: IPB (Bogor Agricultural University)
Abstrak: Hypercholesterolemia and LDL oxidation are the major factors of atherosclerosis. The ethanol extract of the ginger (EEG) and Zn each posses effect reduce cholesterol and antioxidant. These research combined EEG and Zn as antihypercholesterolemia and antioxidant to prevent atheroma in New Zealand white fed rabbits atherogenic diet and hypercholesterolemia rabbits. Twenty eight male rabbits were divided into seven groups. For 6 weeks, group 1 was fed with a normal diet and group 3 was fed with an atherogenic diet. Beside the atherogenic diet, group 2,4,5,6, and 7 were also treated by supplementary treatment. Second phase research, 24 male hypercholesterolemia rabbits were divided into 6 groups. For 6 weeks, group 1 was fed with a normal diet. Fed rabbits atherogenic diet group 2,4,5,6, and 7 and hypercholesterolemia rabbits group 2,3,4,5, and 6 were treated by supplementary treatment, which are Zn 6.67 mg/kg, EEG 200 mg/kg, combination EEG 50 mg/kg and Zn 6.67 mg/kg, combination EEG 100 mg/kg and Zn 6.67 mg/kg, and atorvastatin (positive control) 1.9 mg/kb BW per day. Combination EEG 50 mg/kg and Zn 6.67 mg/kg and combination EEG 100 mg/kg and Zn 6.67 mg/kg treatment impeded the increase of total cholesterol, LDL, and prevent atheroma equal to the positive control. Based on the ability to restrain the increase of MDA (lipid peroxidation) in fed rabbits atherogenic diet the treatment with combination EEG 50 mg/kg and Zn 6.67 mg/kg resulted higher than positive control or the other treatment. Based on reduced plaque atheroma in hypercholesterolemia rabbits, combination EEG 50 mg/kg and Zn 6.67 mg/ kg treatment also the best result. These researches concluded that combination EEG 50 mg/kg and Zn 6.67 mg/kg BW per day treatment exhibited the highest atheroma prevention effect in fed rabbits atherogenic diet or hypercholesterolemia rabbits as compared to the positive control or the other treatments.
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Judul: Estimating Parameter and the Convergence of Parameter Estimator of Poisson Hidden Markov Model
Abstrak: Model hidden Markov terdiri dari sepasang proses stokastik yaitu proses observasi dan proses yang memengaruhi observasi. Proses stokastik yang memengaruhi observasi ini diasumsikan membentuk rantai Markov dan tidak diamati. Model Poisson hidden Markov (MPHM) adalah salah satu model hidden Markov diskret dan proses observasinya jika diketahui proses yang memengaruhinya diasumsikan menyebar Poisson., A hidden Markov model (HMM) consists of a pair of stochastic processes, that is the observation process and process that affected observation. The stochastic process which causes this observation is assumed to form a Markov chain and is not observed. Poisson hidden Markov models (PHMM) is one of the discrete HMM and the observation process given the cause is assumed having a Poisson distribution.
Keyword: Poisson hidden Markov model, Forward-Backward algorithm, Expectation Maximization algorithm