Judul: Kemampuan Antioksidan Asal Tanaman Obat dalam Modulasi Apoptosis Sel Khamir (Saccharomyces cerevisiae)
Abstrak: Penyakit kardiovaskular merupakan penyebab utama kematian terutama di negara-negara Barat. Penyakit ini salah satunya disebabkan oleh adanya radikal bebas. Molekul radikal bebas dan senyawa turunannya antara lain reactive oxygen species (ROS) dapat menyerang sel sehingga menimbulkan berbagai kerusakan pada sistem sel yang disebut apoptosis. ROS dapat menyebabkan terjadinya oksidasi LDL dan bisa memicu apoptosis Antioksidan dapat menetralkan radikal bebas. Antioksidan bersifat sebagai modulator apoptosis yang dapat mengikat ion logam yang terlibat dalam pembentukan ROS. Antioksidan akan melindungi LDL dan dapat mengurangi dampak klinik terjadinya penyakit vaskular dan pembentukan plak aterosklerosis. Berbagai tanaman telah sering digunakan secara tradisional oleh masyarakat untuk mengobati penyakit kardiovaskular. Pada penelitian ini digunakan ekstrak daun dari beberapa tanaman yang digunakan dalam pengobatan kardiovaskular dan berpotensi sebagai antioksidan. Tanaman tersebut adalah salam (Eugenia polyantha Wight), jati belanda (Guazuma ulmifolia Lamk.) dan jambu biji (Psidium guajava). Pengaruh ekstrak senyawa bahan alam yang memiliki kemampuan modulasi apoptosis ditentukan dalam sistem nonmamalia mengunakan sel ragi (Saccharomyces cerevisiae) karena adanya kesamaan fenomena apoptosis antara sel ragi dan sel mamalia. Penelitian ini bertujuan untuk menentukan pengaruh potensi antioksidasi dari ekstrak daun salam (Eugenia polyantha Wight), daun jati belanda (Guazuma ulmifolia Lamk.) dan daun jambu biji (Psidium guajava) terhadap kemampuan dalam memodulasi apoptosis pada sel khamir (Saccharomyces cerevisiae). Hasil penelitian ini diharapkan dapat memberikan informasi ilmiah mengenai khasiat antioksidasi ekstrak daun salam (Eugenia polyantha Wight), daun jati belanda (Guazuma ulmifolia Lamk.) dan daun jambu biji (Psidium guajava) dalam mencegah penyakit kardiovaskular.
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Judul: Kemampuan Ekstrak Dedaunan Berpotensi Antioksidan Untuk Memodulasi Apoptosis Pada Sel Khamir.
Abstrak: One of the causes of cardiovascular disease is atherosclerosis. Some of medicinal herbs extracts which are reported to have anti atherosclerotic property are Guava leaves extract, Jati Belanda leaves extract, and Salam leaves extract. Apoptosis occures in atherosclerosis lesions intima. So this research is to determine that the capability of some herbal extracts to modulate apoptosis in yeast cells. For that purpose, yeast cells are used as model, as they will become small colonies (petite colonies) when apoptosis is induced. Yeast cells were incubated into 50 ppm, 100 ppm, 200 ppm, 1000 ppm, and 2000 ppm of each extracts, previously had been enriched in sterile YEPD and Petite Broth. On day 3 and 4, yeast cells were spread into YEPD and Petite media, and then petite frequency was counted directly from the plate. Promising extract for apoptosis stimulation on yeast cells is the 100 ppm Salam leaves extracts has petite frequency of 97.90%, whereas the 1000 ppm and 2000 ppm petite frequency are respectively 94.45% and 91.99%. No petite colony was formed on other extracts. Guava leaves extracts at 100 ppm inhibits apoptosis on yeast cells.
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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