Judul: Potensi Kulit Buah Langsat (Lansium domesticum) sebagai Antibakteri
Abstrak: The fruit peels of langsat (Lansium domesticum) have antibacterial activities. However, the active compounds responsible for the activities have not been studied. Therefore, this research was aimed to determine the metabolite compounds with antibacterial activity in the fruit peel of langsat. Some samples was macerated using ethanol 70% and further fractionated using column chromatography with gradient elution from non-polar to polar solvent. Antibacterial activity was tested to Staphylococcus aureus using dilution method. Antibacterial test results showed that the most active extracts was ethanol 70% extract with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 1.00 mg/mL. Fractionation using hexane:ethyl acetate gave 12 fractions and 9 fractions for ethyl acetate:methanol. The most active fraction was F29 with MIC and MBC of 0.5 mg/mL and 2.00 mg/mL, respectively. Based on identification using Fourier transform infrared spectrophotometers, the predicted active compound was flavonoids.
Keyword: fruit peels langsat, fraction, flavonoid, antibacterial

Judul: Pengaruh Fraksionasi pada Aktivitas Antioksidan Ekstrak Kulit Buah Langsat (Lansium domesticum)
Abstrak: Langsat (Lansium domesticum) fruit’s peel has been reported to have antioxidant activity but the active compound has yet to be verified. The study objectives were to evaluate antioxidant activities from the crude extract of langsat fruit’s peel and its fractions. The crude extract was obtained through maceration method in 70% ethanol and ethyl acetate. The antioxidant activity was tested by 2,2-diphenyl-1-picrilhydrazil method. The extract with the best activity was further fractionated with the best eluent obtained. The best antioxidant activity was showed by crude 70% ethanol extract with 50% inhibition concentration (IC50) value of 372.90 ppm. The phytochemical compounds in the extract were tannins, flavonoids, alkaloids, and saponins. The fractionation was done by using column chromatography via step gradient elution with at combination of n-hexana and ethyl acetate with increasing polarity giving. 12 fractions which were further tested for their antioxidant activities. However, all fractions did not have antioxidant activities as the inhibition percentage were below 50%.
Keyword: Lansium domesticum, phytochemicals, fractionation, antioxidant

Judul: Analisis Struktur Atas Gedung Diploma IPB terhadap Beban Gempa Berdasarkan SNI 03-1726-2002 dan SNI 03-1726-2012
Abstrak: Gedung Diploma IPB masih menggunakan SNI 03-1726-2002 dalam perencanaan strukturnya. SNI tersebut kemudian diubah seiring dengan keluarnya peraturan baru yang termuat dalam SNI 03-1726-2012. Tujuan dari penelitian ini adalah mengetahui ketahanan struktur atas gedung Diploma IPB terhadap beban gempa ditinjau berdasarkan waktu getar alami dan partisipasi massa, mengetahui besarnya gaya geser dasar seismik, dan membandingkan besarnya simpangan berdasarkan kedua SNI. Partisipasi massa arah X yang dihasilkan yaitu sebesar 0.9417 pada modal ke 9 dan 0.9006 pada modal ke 12 pada arah Y. Kedua nilai tersebut telah memenuhi kedua standar SNI. Waktu getar alami telah memenuhi standar SNI 2002, namun belum memenuhi standar SNI 2012. Gaya geser dasar dinamik yang dihasilkan berdasarkan SNI 2012 sebesar 1599.6606 kN akibat gempa arah X dan 1223.5794 kN akibat gempa arah Y, sedangkan berdasarkan SNI 2002 untuk arah X sebesar 1544.5109 kN dan untuk arah Y sebesar 1544.8304 kN. Simpangan antar lantai telah memenuhi persyaratan kedua standar SNI. Struktur Gedung Diploma IPB telah memiliki kekakuan yang cukup dan terhitung boros, sehingga seharusnya dapat direncanakan dengan lebih hemat biaya.
Keyword: beban gempa, gaya geser dasar, simpangan, struktur atas