Judul: Pemisahan Sitral dari Minyak Atsiri Serai Dapur (Cymbopogon citratus) sebagai Pelangsing Aromaterapi
Abstrak: One of Indonesian herbs that contain essential oil is lemongrass. Essential oil of lemongrass consist of citral as the main component. This research aim to separate citral from lemongrass oil and to analyze its potency as slimming aromatherapy. Citral was separated from lemongrass oil by precipitating using sodium bisulphite and diluting using NaOH. Citral then was fractionated by preparative thin layer chromatography (PTLC) that resulted F1 (near start point) and F2 (near final point). Essential oil, citral, and F2 from PTLC were analyzed by gas chromatography-mass spectrometry. The potency as slimming aromatherapy was analyzed in vivo on adult male Sprague-Dawley rats. Inhalation result of essential oil, citral, and F2 showed that the average body weight of rats after 5 weeks treatment period was lower than the normal group and the control group which consumed high cholesterol feed. The rats inhalated sitral had the lowest body weight at the end of treatment as a compare rats inhalated essential oil and F2. In conclusion, citral is a compound that is has potency as slimming aromatherapy.
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Judul: Pemisahan eugenol dari minyak atsiri daun cengkih (Syzygium aromaticum) sebagai pelangsing aromaterapi secara in vivo
Abstrak: Clove contains essential oil with eugenol as major component. This study aims to separate eugenol in the essential oil of clove leaves and analyze its potency as slimming aromatherapy by in vivo assay. Eugenol from essential oil of clove leaves was separated by chemical and gave 2 fractions, namely eugenol fraction and nonpolar fraction. Analysis of gas chromatography-mass spectrometry showed that eugenol fraction contain eugenol with the purity of 85%, while the nonpolar fraction containd 35% of β-caryophyllene. In vivo assay showed that the rat group inhalated essential oil of clove leaves had significant difference in average weight as compared with group inhalated eugenol fraction in level of confidence 95%. Inhalation of essential oil of clove leaves also tend to have lower response on the body weight as compared to the negative control group. It showed that inhalation of clove leaves with 1% concentration is potential as slimming aromatherapy by decreasing 13% of rats weight .
Keyword: slimming aromatherapy, eugenol, essential oil of clove leaves

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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