Judul: Aplikasi Poli(asam laktat) sebagai Mikrosfer Pengungkung Obat Selekoksib
Abstrak: Mikrosfer polimer biodegradabel, poli(asam laktat) (PLA) berisi selekoksib dibuat dengan metode penguapan pelarut dalam air. Mikrosfer yang dihasilkan dari metode ini homogen dan selekoksib terdistribusi di dalam matriks polimer. Parameter yang diamati adalah ukuran mikrosfer, efisiensi pengungkungan dan lepasan obat selekoksib secara in vitro. Pengamatan morfologi mikrosfer menggunakan scan electron microscope dan kristalinitasnya dengan XRD. Mikrosfer berisi obat diinkubasi dalam bufer fosfat + 2% Tween-80 pH 7.4, diperoleh lepasan awal yang meletus pada dua jam pertama diikuti dengan lepasan yang tetap sampai waktu inkubasi 24 jam. Hasil penelitian ini memperlihatkan ada pengaruh ukuran mikrosfer berisi obat selekoksib pada lepasan awal dari matriks polimer. Obat yang lepas dari mikrosfer dengan kandungan obat yang rendah (1% w/w) dipengaruhi oleh ukuran partikel. Naiknya kandungan obat dalam mkirosfer mulai 1% b/b sampai 5% b/b secara nyata obat lebih cepat lepas dari mikrosfer. Kata kunci: poli(asam laktat), mikrosfer, selekoksib, metode penguapan pelarut.
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Judul: Optimasi pembuatan mikrosfer polipaduan poliasamlaktat dengan polikaprolakton
Abstrak: Mikrosfer dapat digunakan sebagai sistem pembawa obat. Mikrosfer dibuat dari polipaduan antara poli(asam laktat) (PLA) dan polikaprolakton (PCL) dengan nisbah 9:1. Mikrosfer dibuat dengan metode emulsifikasi: PLA dan PCL dilarutkan dalam pelarut atsiri (diklorometana) lalu diemulsikan dan didispersikan ke dalam pelarut lain (air) sehingga terbentuk mikrosfer.Ukuran dan keseragaman mikrosfer dipengaruhi oleh kecepatan putar dan waktu emulsifikasi. Poli(vinil alkohol) (PVA) digunakan sebagai pengemulsi pada pembuatan mikrosfer polipaduan (PLA dengan PCL). Besarnya konsentrasi PVA yang ditambahkan memengaruhi stabilitas emulsi tersebut sehingga memengaruhi keseragaman ukuran mikrosfer yang didapatkan. Penggunaaan waktu emulsi 90 menit dan kecepatan putar 900 rpm meningkatkan keseragaman dan ukuran mikrosfer yang dihasilkan semakin kecil. Mikrosfer yang dihasilkan seluruhnya berukuran kurang dari 50 μm. PVA 2,50% mampu menghasilkan mikrosfer berukuran kurang dari 1 μm dengan persentase terbanyak, yakni sebesar 44,10% dan 55,90% sisanya berukuran 24-39 μm. Hal ini menunjukkan bahwa konsentrasi PVA 2,50% tidak hanya menghasilkan mikrosfer yang berukuran kecil, tetapi juga relatif seragam.
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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