Judul: Aktivitas Antibakteri Ekstrak Daun Sengon (Falcataria moluccana (L) Nielsen) terhadap Bakteri Staphylococcus aureus dan Escherichia coli
Abstrak: Disease by infection is most suffered by people and developed from time to time in medicines. The last research showed that Falcataria moluccana leafs had fitochemical compounds and potential as antibactery. The research aimed to study the antibacterial compounds activity of Falcataria moluccana leafs extract at S. aureus and E. coli with gel diffusion (well method). The leafs used in this research were leaf extract from extraction of aquades, ethanol 70%, ethanol 96%, and ethyl acetate. The concentrations were 50, 100, 150, 200, 250, and 300 mg/mL for each solvents. The result showed that aquades extract could not inhibit the growth of bacteria, while ethyl acetate and ethanol extracts showed antibacterial activity. The largest antibacterial activity showed by ethyl acetate extract at concentration 300 mg/mL with inhibiton areas 6.90 and 4.97 mm for S. aureus and E. coli. This values included in medium category. The result of Analysis of Variance with SPSS 16. program for windows showed that variance of solvents and concentration were significantly difference for inhibition areas.
Keyword: Falcataria moluccana (L) Nielsen, S. aureus, E. coli, antibactery

Judul: Kajian Aktivitas Antibakteri Daun Gatel (Laportea decumana (Roxb.) Wedd.) dan Daun Benalu Cengkeh
Abstrak: Many researches showed that several plants have a good antibacterial activity. The leaves of gatel and clove mistletoe are empirically used to cure several diseases. The aims of this research were: (1) to study the potential of antibacterial activity of gatel and clove mistletoe hexane, ethyl acetate and methanol extracts against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa by the well diffusion method; (2) to calculate the minimum inhibitory concentration (MIC) value of the potential extracts; and (3) to study the effect of various pH to antibacterial activity of the extracts. The results showed ethyl acetate and methanol extracts of the studied plants have low antibacterial activity against B. cereus and E. coli. Based on the MIC values, the ethyl acetate extract of gatel leaves showed over 99% percent inhibition against E. coli at a concentration of 3.5%, 4.0%, 4.5% and 5.0%. The same result was obtained by modifying the pH (4, 5 and 6) at the extracts concentration of 5% and 10%. The methanol extract of gatel leaves showed below 60% inhibition of B. cereus at a concentration of extract 4.0%, 4.5%, 5.0%, 5.5% and 6.0%, and more than 90% inhibition at the pH. The ethyl acetate extract of clove mistletoe showed more than 98% inhibition againts E. coli at a concentration of 3.5%, 4.0%, 4.5% and 5.0% and at pH 4, 5 and 6. Percent of inhibition less than 50% occured in the methanol extract of clove mistletoe at 4.0%, 4.5%, 5.0%, 5.5% and 6.0% concentration against B. cereus. For the methanol extract of clove mistletoe, the effect of pH variation (4, 5, 6 and 7) resulted in 92%-97% inhibition. The result may increase the utilization of research plant not only for health purposes but also as a natural food preservative and open new possibilities for the development of natural functional foods.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh.
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. ,,,
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular.