Judul: Perbandingan Daya Hambat Ekstrak Siwak (Salvadora persica) Dan Larutan Kumur Komersil Terhadap Pertumbuhan Bakteri Mulut
Abstrak: The research aimed to find out antibiotic properties of siwak extraction solution and compared it to commercial mouthwash solution. The siwak extraction solution showed poor inhibition activity to isolated mouth bacteria than BET and TC mouthwash solution, respectively. The TC mouthwash solution showed more effective to inhibited the bacteria than BET mouthwash solution and siwak extraction solution.
Keyword: 

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.
Keyword: 

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
Keyword: