Judul: Ekstraksi dan isolasi zat aktif dari mikroalga Scenedesmus acuminatus dan pengaruhnya terhadap pertumbuhan bakteri dan khamir
Abstrak: Mikroalga sebagai salah satu komoditi perikanan memiliki potensi yang besar untuk dimanfaatkan. Bebera- pa mikroalga telah diketahui dapat menghasilkan berbagai bahan bioaktif. Sebagai sumber bahan kimia mikroalga dapat mengha- silkan produk seperti gliserol, beta karotin, vitamin dan bahan-bahan bioaktif. Bahan bioaktif yang telah diketahui dapat dihasilkan dari mikroalga yaitu: anti oksidan, algicides, toksin, bahan obat-obatan dan zat pengatur pertumbuhan. Zat pengatur pertumbuhan merupa- kan zat aktif yang menarik perhatian para peneliti karena aktifitasnya yang bersifat memacu pertumbuhan. Mikroalga mengandung vitamin-vitamin yang terbagi menjadi dua kelompok yaitu kelompok vitamin yang terda- pat dalam sel (vitamin content) dan kelompok vitamin yang diekskresikan oleh sel mikroalga ke dalam media pertumbuhannya (excreted vitamin). Vitamin termasuk dalam kelompok faktor pertumbuhan yang dapat berpengaruh terhadap pertumbuhan mikroorganisme. Tujuan penelitian ini adalah untuk mengekstraksi zat aktif dari mikroalga Scenedesmus acuminatus dan mempelajari pengaruhnya ...
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Judul: Pemisahan Ekstrak lntraseluler dari Mikroalga  Nitzschia closterium dan Penentuan Konsentrasi Hambatan Minimumnya Terhadap Mikroba Patogen
Abstrak: Mikroalga merupakan salah satu biota perairan yang belum banyak dimanfaatkan secara optimal. Di Indonesia, pemanfaatan biota ini hanya terbatas sebagai pakan alami. Selain sebagai pakan, mikroalga merupakan salah satu sumber bahan aktif dan bahan kimia yang sangat potensial. Sejumlah peneliti menyatakan pendapatnya secara pasti bahwa beberapa spesies mikroalga menghasilkan metabolit intraseluler dan ekstraseluler yang dapat menghambat pertumbuhan organisme lain. Selain vitamin, asam amino, karbohidrat dan nutrien lainnya, mikroalga juga mengandung komponen aktif biologi yang didalamnya juga termasuk antibiotik, algasidal, racun, komponen aktif farmasi (antitumor, antikanker) dan komponen pemacu pertumbuhan.
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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