Judul: Degradasi Poliblend Kopolimer Poli(Asam Laktat-co-Asam Glikolat) dan Poli(å-kaprolakton) secara In Vitro
Abstrak: Polimer telah banyak diaplikasikan dalam kehidupan manusia, salah satunya adalah untuk penyalut obat. Polimer sintetik seperti poli(asamlaktat) (PLA), poli(asamglikolat) (PGA), poli(å-kaprolakton) (PCL), poli(asam laktat-co-asam glikolat) (PLGA) merupakan jenis-jenis poliester yang banyak digunakan untuk penyalut obat. Para peneliti telah banyak yang melakukan penelitian tentang degradasi PLA, PGA, PCL, dan PLGA, tetapi belum ada yang melakukan penelitian tentang degradasi poliblend polimer ini, salah satunya adalah poliblend PLGA dan PCL. Poliblend dibuat empat komposisi, yaitu PLGA (90:10):PCL 3:1, PLGA(75:25):PCL 3:1, PLGA (90:10):PCL 5:1, dan PLGA (75:25):PCL 5:1. Degradasi dilakukan selama delapan minggu dengan menggunakan bufer fosfat pH 7.4 dan suhu inkubasi 37°C. Degradasi polimer diamati dengan adanya perubahan massa, viskositas intrinsik, dan bentuk permukaannya. Hasil penelitian menunjukkan bahwa komposisi PLGA (75:25):PCL 5:1 merupakan komposisi yang paling cepat terdegradasi dibandingkan dengan komposisi lainnya. Ini terlihat dari perubahan massa hingga 89.06% dan viskositas intrinsik hingga 20.13%.
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Judul: Degradasi in vitro mikrosfer polipaduan poli(asam laktat) dan poli (kaprolakton)
Abstrak: Poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) are examples of polymer that can be used as a matrix in drug delivery system because of its degradability property. Drug encapsulation system could be achieved by microspheres formation with emulsion method. The aim of this research was to examine in vitro degradation of microspheres obtained from PLA-PCL polyblend at pH 7.4. Several stages in the study consisted of PLA synthesis, mixing of PLA-PCL in polyblend, microspheres formation, shape and texture observation, and in vitro degradation test. Synthesis PLA produced a polymer with molecular weight 6064 g/mol. Microspheres were formed by emulsification with polyvinylalcohol (PVA) 1.5% (v/v) as an emulsifier. Physical texture of the microspheres was observed with stereomicroscope and scanning electron microscope (SEM). Degradation was analyzed weekly by measuring its molecular weight and viscosity using a digital viscometer, while its weight loss was measured using an analytical balance. The results showed that the composition of PLA microspheres: PCL (9:1) had degradation time faster than the others and it also affected morphological structure, viscosity, and weight of microsphere during degradation analysis. The higher the PLA composition the lower the viscosity value, therefore, the lower the molecular weight of microspheres. During degradation time, viscosity value and weight loss percentage decreased gradually. Kinetics of microsphere weight loss followed between zero and first order kinetic model.
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Judul: Populasi dan Habitat Kakatua-Kecil Jambul-Kuning di Bentang Alam Mbeliling Bagian Barat, Kabupaten Manggarai Barat, Nusa Tenggara Timur
Abstrak: Cacatua sulphurea parvula or yellow-crested cockatoo were spread distributed at Sunda Kecil Archipelago, Nusa Tenggara, except at Sumba Island. This species amount in the nature is very small, caused by the illegal hunting and trading. The purpose of this research is to get the information about population and habitat of the cockatoo in Flores, especially at the western part of Mbeliling Landscape. Cocatoo census was conducted by look-down method at vantage points when cockatoo flew passed by. Habitat analysis was carried out with vegetation analysis. The census showed that there were two groups of cockatoo, consisted of 69 cockatoos in Tao hill and 15 cockatoos in Nggoer River. Flight pattern of each group ranged 0-100 meters above the sea level and crossed mangrove forest, savanna, monsoon forest and cultivation plant vegetation. The vegetation analysis resulted Ceiba petandra or silk-cotton tree as the tree that most used by cockatoo and had the highest TIV (Tree Importance Value), 47,48%. Cockatoo’s foods which observed were crown flower (Calotropis gigantea), and Moringa olifera. The population of Cockatoo which observed at western part of Mbeliling Landscape was estimated came from Rinca Island, Komodo National Park. It can be concluded that the location might be only used by rhe cockatoo came from Rinca Island as their daily exploration area for foraging.
Keyword: habitat., ecology, population, Flores, Cacatua sulphurea parvula