Judul: Evaluasi Keberadaan dan Posisi Gugus Prenil pada Aktivitas Antioksidan Kuersetin di Cincin A Berdasarkan Teori Fungsional Rapatan B3LYP.
Abstrak: Kuersetin merupakan anggota flavonoid golongan flavonol yang memiliki beberapa aktivitas hayati, salah satunya ialah aktivitas antioksidan. Pada penelitian ini, aktivitas antioksidan kuersetin dan kuersetin berprenil di posisi 6 dan posisi 8 diperkirakan menggunakan 3 parameter, yaitu energi pemutusan ikatan (EPI), potensial ionisasi (PI), dan selisih energi orbital molekul (Egap) pada tingkat B3LYP/6-31G(d). Mekanisme antioksidan yang dikaji adalah pemutusan ikatan antara atom hidrogen dan oksigen pada gugus fenolik baik secara homolitik maupun heterolitik, sehingga perhitungan EPI dan PI memenuhi asumsi tersebut. Secara keseluruhan, keberadaan gugus prenil di posisi 8 pada kuersetin meningkatkan aktivitas antioksidan dengan menurunnya nilai EPI, nilai PI, dan nilai Egap terhadap kuersetin..
Keyword: antioksidan, Egap, EPI, kuersetin, PI, prenil

Judul: In silico Study: The Study Between The Relationship of Prenyl and Antioxidant Activity on Some Flavonoids
Abstrak: Flavon dan flavonol merupakan contoh senyawa anggota flavonoid yang memiliki beberapa aktivitas biologis, salah satunya aktivitas antioksidan. Pada penelitian ini, perhitungan energi pemutusan ikatan (BDE) dilakukan terhadap 4 contoh golongan senyawa dari masing-masing golongan flavon dan flavonol terprenilasi. Mekanisme antioksidan yang dikaji adalah pemutusan ikatan antar atom oksigen dan hidrogen pada gugus fenolik, baik secara langsung maupun tidak langsung, sehingga perhitungan BDE dan potensial ionisasi (PI) memenuhi asumsi tersebut. Secara keseluruhan, gugus yang menjadi penyebab meningkatnya nilai BDE secara signifikan adalah cincin piran-7OH dengan tambahan prenil. Sementara, keberadaan cincin piran-5OH disertai prenil tambahan pada posisi 8 merupakan penyebab meningkatnya nilai PI secara tajam. Dari 176 contoh senyawa yang telah dihitung, krisin merupakan golongan senyawa yang pada umumnya mengalami peningkatan aktivitas antioksidan setelah terprenilasi (ΔBDE = -1,708 - -27,728 kcal/mol). Penurunan aktivitas antioksidan paling banyak terjadi pada golongan senyawa kuersetin dan kaemferol terprenilasi. Dari hasil penelitian ini, dapat disimpulkan bahwa penambahan gugus prenil secara umum menurunkan aktivitas antioksidan flavon dan flavonol.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, antioxidant, BDE value, prenyl, radical position, Flacon, Nilai BDE, Posisi radikal

Judul: Biology and ecology of the buffalo fly, haematobia exigua de meijere (diptera:muscidae)
Abstrak: The life history of the buffalo fly was observed at room temperature of 27°-29.5°C and at a relative humidity of 48-68 percent. The eggs hatched after 17-22 hours, with an average of 18 hours. First instar larvae measured 1.25 + 0.16 mm long and 0.27 + 0.037 mm wide. reach the second larval stage. It took 6-12 hours to the second instar larvae measured 2.676 +0.187 mm long and 0.353 +0.028 mm wide. The second instar took about 12-24 hours to reach the third larval stage. The third instar measured 6.833 + 0.189 mm long and 0.919 + 0.051 mm wide. It took about 2-3 days for the third instar to become pupae. Duration of the pupal stage was about 5-7 days before the adults emerged. Under laboratory condition, the buffalo fly completed its life cycle in 9.5 to 10.5 days, whereas under field condition it took 9-14 days with an average of 10.5 days. The growth ratio which was based on the measurements of the cephalo-pharyngeal skeleton of each instar was 1.797. The preoviposition period was 8-12 days and mating usually occurred on the 6th or 7th day. The longevity of the male was 29 days, whereas it was 32 days in the female. The range of egg production under laboratory condition was between 20-139 per female fly. The belly and hind legs of the carabao were the most preferred habitat either during cloudy and cool dry or shiny and warm day. When the weather was clear and the carabao was in the shade, the flies tended to be more distributed particularly on the shoulder, dewlap, back and horns. The carabaos had relatively fewer Musca sp. and Stomoxys calcitrans than cattle; never the less carabaos had a higher infestation of buffalo fly than cattle. Oviposition occured either during the day or night but the buffalo flies were more active during the night than in the day time. The effect of various lengths of exposure time of manure in relation to the oviposition was profound. observed, the maximum number of the buffalo flies was occurred when the dung was exposed for 30 minutes. With increasing time of exposure the number and variety of insects also increase. It was evident that Sepsidae and psychodidae were the most dominant insects emerging from the dung. The number of buffalo flies also increased with increasing
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