Judul: Properties of Antibacterial Miswak Wood Extractives (Salvadora persica Wall.) for Streptococcus sp
Abstrak: Miswak wood (Salvadora persica Wall.) is a wood that has been known since ancient times, especially by the ancient Arabian, which until now still uses it. A comparative study of periodontal treatment is done on miswak users with non miswak users resulting that miswak user groups have lower periodontal treatment than non user groups (Al-Lafi and Ababneh, 1995). In the mouth, there are different kinds of microbes that are normal flora. This is because the oral cavity is the gateway connecting external environment and internal of the body, so that microbes can enter and multiply in our bodies. The caries forming process involves a number of factors that interacts each other that are tooth and saliva (host), microorganisms, substrate and time. The process of dental caries occurrence begins with demineralisation of dental hard tissue that is followed by organic material damage teeth. Demineralisation of dental hard tissue is caused by acid because of carbohydrate fermentation by microorganisms. One of the microorganisms in the oral cavity which is kariogenik bacteria is Streptococcus sp.. The number of Streptococcus sp. contained in the saliva showed that the bacteria are also a lot of in plaque and tooth surface. The aim of this study is to determine the effect of miswak extracts at various levels of concentration against the growth of Streptococcus sp. This research used miswak sawdust obtained from PT. Miswak Utama then extracted with acetone. Acetone extract was then gradually fractionated in different solvent based on solvent polarity level, i.e. nhexane, ether, and ethyl acetate. Concentration of 10 mg / ml, 15 mg / ml, 20 mg / ml, 25 mg / ml, and 30 mg / ml was made for each fraction of extractives and each concentration was tested duplo against Streptococcus sp.. Well-diffused agar method was used to test the anti-bacterial property. Mueller-Hinton Agar medium was inoculated by Streptococcus sp. and spreaded by a hockey stick. Five wells were made in a Petri dish and each different well was applied by the extract with different concentration. After that, the Petri dish was incubated at 37°C for 24 hours. Indicator of the inhibition is formation of inhibitory zone surrounding of the well. Miswak wood (Salvadora persica Wall.) yielded 1.16% of extractive substances. Fractionation of miswak acetone extract contained 0.37% n-hexane fraction, 0.38% ether fraction, 0.07% ethyl acetate fraction, and 0.34% residue. Meanwhile, anti-bacterial properties test showed the residue has inhibitory zone larger and the MIC values lower than the other fractions.
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Judul: Aktivitas Anticendawan Ekstrak Etanol Kayu Siwak (Salvadora persica) Dan  Larutan Kumur Komersial Terhadap Candida Albicans Secara In Vitro
Abstrak: The aim of this study were to investigate the antifungal activity and the effect of siwak ethanol extract in comparison with commercial mouthwash on inhibition of C. albicans growth during in vitro condition. Mouthwash #1 is containing alcohol, Mouthwash #2 is containing fluoride, and Mouthwash #3 is containing povidone iodine. Siwak extracts showed the different results to control significantly, but the effects were not depending on their concentration. The concentration of siwak extract showed no effect on C. albicans growth. The antifungal effect of siwak extract was less than other commercial mouthwash for all extract concentrations.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf