Judul: Inhibisi fraksi aktif daun dandang gendis (Clinacanthus nutans) pada pertumbuhan Saccharomyces cerevisiae sebagai uji potensi antikanker
Abstrak: Isolasi senyawa bioaktif yang dilakukan dalam penelitian ini diawali dengan pengeringan dam dandang gendis (Clinachantus nutans), kemudian dibuat menjadi serbuk. Serbuk ini diekstraksi dengan pelarut etanol 96% dengan cara maserasi, lalu ekstrak kasar diuji fitokimia dan uji toksisitas BSLT (brine shrimp lethality test) kemudian difraksinasi dengan kromatograli cepat dengan fase dim silika G-60 dan fase gerak etil asetat:heksana 8:2. Fraksi teraktif diperoleh dari hasil uji BSLT kemudian diuji kemampuan inhibisinya terhadap pertumbuhan Saccharomyces cerevisiae dan diidentifikasi menggunakan uji fitokimia.
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Judul: Isolasi Fraksi Aktif Ekstrak Daun Dandang Gendis (Clinacanthus nutans) Berpotensi sebagai Antibakteri
Abstrak: Ethanol extract of dan dang gendis leaves have been known to be toxic toward Artemia salina brine shrimp. This toxicity property was likely due to the existences of some of its secondary metabolites that have antibacterial properties. Hence, this plant could be used as a substitute of the synthetic drugs usage. The purpose of this study was to find the most active fraction of ethanol extracts of dandang gendis leaves as a potential antibacterial and to determine the group of the active compound. The ethanol extract was fractionated using flash chromatography with silica gel as the stationary phase and ethyl acetate: n-hexane (8:2) as the 1110bile phase resulted in total of four fractions (fraction I to 4). Then the capability of those fractions, to inhibit the growth of two types of bacteria, Escherichia coli and Staphylococcus aZlreliS was tested. Fractions I with concentration of 1000 ppm had the largest inhibitory zone with the area of 4.17 and 7 mm in diameter when it was tested on E. coli and S. aureus respectively. The formation of inhibitory zone showed that fraction I of the ethanol extract of danclang gendis to have a weak antibacterial effect toward E. coli and moderate effect (5-10 Illm) on S. aureus. Based on the phytochemical assay, fraction 1 showed positive result on steroid and flavonoid tests
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Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite