Judul: Antibacterial Activity of Neem (Azadirachta indica) Leaf Extract Using Agar Disc Diffusion Method
Abstrak: Neem (Azadirachta indica) has traditionally been considered one of the most versatile medicinal plants that possesses a wide spectrum of biological properties including anti–inflammatory, anti–arthritic, anti–pyretic, anti–gastric ulcer, antibacterial, antifungal, antiviral, antioxidant, antimalarial, antidiabetic and antitumor activities. In this study, the agar disc diffusion method was used to determine the antibacterial activity of ethanolic neem leaf extract against three Staphylococcus aureus isolates from different sources which are human skin, snake mouth and cow milk, Staphylococcus epidermidis, Micrococcus sp., Bacillus sp., and Serratia sp. Neem leaf extract at concentrations of 40%, 60% and 80% were used with negative controls of water and ethanol as well as a positive control of Penicillin-G antibiotics. Inhibition zones were observed after 24-hour incubation, of the neem leaf extract at all concentrations to all Gram–positive bacteria which are S. aureus, S. epidermidis, Micrococcus sp. and Bacillus sp. Bacillus sp. was shown to have the highest sensitivity to the neem leaf extract. The largest zones of inhibition were observed at the 80% concentration of neem leaf extract in all bacteria excluding Serratia sp. Gram–negative bacteria Serratia sp. was resistant to the antibacterial effects of the neem leaf extract.
Keyword: Agar disc diffusion, antibacterial, Azadirachta indica, Bacillus sp., Micrococcus sp., Neem, Serratia sp., Staphylococcus aureus, Staphylococcus epidermidis

Judul: Antibacterial Activity of Neem (Azadirachta indica) Leaf Extract Using Agar Disc Diffusion Method
Abstrak: SETIYANINGSIH and USAMAH AFIFF Neem (Azadirachta indica) has traditionally been considered one of the most versatile medicinal plants that possesses a wide spectrum of biological properties including anti–inflammatory, anti–arthritic, anti–pyretic, anti–gastric ulcer, antibacterial, antifungal, antiviral, antioxidant, antimalarial, antidiabetic and antitumor activities. In this study, the agar disc diffusion method was used to determine the antibacterial activity of ethanolic neem leaf extract against three Staphylococcus aureus isolates from different sources which are human skin, snake mouth and cow milk, Staphylococcus epidermidis, Micrococcus sp., Bacillus sp., and Serratia sp. Neem leaf extract at concentrations of 40%, 60% and 80% were used with negative controls of water and ethanol as well as a positive control of Penicillin-G antibiotics. Inhibition zones were observed after 24-hour incubation, of the neem leaf extract at all concentrations to all Gram–positive bacteria which are S. aureus, S. epidermidis, Micrococcus sp. and Bacillus sp. Bacillus sp. was shown to have the highest sensitivity to the neem leaf extract. The largest zones of inhibition were observed at the 80% concentration of neem leaf extract in all bacteria excluding Serratia sp. Gram–negative bacteria Serratia sp. was resistant to the antibacterial effects of the neem leaf extract.
Keyword: Agar disc diffusion, antibacterial, Azadirachta indica, Bacillus sp., Micrococcus sp, Neem, Serratia sp., Staphylococcus aureus, Staphylococcus epidermidis

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.