Judul: Antioxidant Activities of Some Medicine Plant Use Natural Zeolite as Supporting Material
Abstrak: Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research. In this report, five plants were selected and collected from Bogor areas. The dried plants were separated into leaves: kedawung (Parkia roxburghii G. Don), salam (Syzygium polyanthum Wight), sirih merah (Piper crocatum Ruiz & Pav), jambu biji (Psidium guajava), and rhizome: bangle (Zingiber cassumunar, syn. Z. purpureum Roxb.). Each plant was extracted with ethanol 30% and 96%. The extracts were tested for their antioxidant activity using a DPPH free radical assay. Identification of crude extract of the compound used phytochemical test and thin layer chromatography tehnique. The results of the best antioxidant activity formula showed by the formulation of kedawung and guava. Formula with ratio of 4:1 selected formula was mixed with supporting material, which were natural zeolit from Bayah and Cikalong. The antioxidant activity of composite extract formulation with zeolite were optimum at 0.1 mg/mL extract formulation, 100 mg Bayah zeolite and 500 mg Cikalong zeolite. Zeolite as supporting material also showed lower antioxidant activity tan extract formulation.
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Judul: Formulasi Ekstrak Kulit Buah Delima dan Daun Dewandaru sebagai Sediaan Antibakteri dan Penggunaan Zeolit untuk menjaga Stabilitas Formula
Abstrak: The aim of this research is to perform a medicinal plant extracts formulation of antibacterial compounds and to recognize the potential of natural zeolite in combination with the antibacterial compounds. The formulation begins with a single extract activity assay followed by combining a single extracts in various comparisons. Results extract formula combined with zeolite and then tested to heat at a temperature of 38oC for 24 hours. The results showed that the highest activity was shown by the ethanol extract of pomegranate peel against bacteria Bacillus cereus and Staphylococcus aureus. Formula extracts obtained from two medicinal plant extracts as antibacterial compounds were able to inhibit the growth of Staphylococcus aureus. Natural zeolites are combined with extract formula able to maintain the antibacterial activity of the extract formula heat effect on the temperature of 38oC for 24 hours.
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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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