Judul: Study of microencapsulated bioinsecticide from Bacillus thuringiensis
Abstrak: Bacillus thuringiensis is one of well known bioinsecticide resources. Bioinsecticide is utilized in organic farming for the replacement of chemical insecticide. Weaknesses of B. thuringiensis toxin are easily disrupted by ultra violet from sunlight and easily washed by rain. The purposes of this research were to produce microencapsulated B. thuringiensis and to produce microencapsulated formula for the protection of toxin active ingredient from the environmental factor. The experimental result showed maltodextrin can be used as an encapsulation material for bioinsecticide using spray drying process. Lactose could not be used as an microencapsulation agent in spray dryin process, especially for areas with high humidity levels due to its low Tg ( Temperature of glass transition) characteristic. Increase ratio in concentration of encapsulation material increased the number of spores contained but gave lower product toxicity. Result showed that 5% maltodextrin concentration produce highest level product of toxicity, but because of poor quality of encapsulation material formed, the product showed high level of degradation after drying process. Rainfall simulation test showed that product encapsulated by maltodextrin gave increase persistence against rain wash on leaf but it could not protect active ingredient deterioration caused by sunlight.
Keyword: 

Judul: Formulasi Produk dan Penurunan Mutu selama Penyimpanan Bioinsektisida Bacillus Thuringiensis subsp. aizawai dari Limbah Industri Tahu
Abstrak: Bioinsecticide can kill insects and disease vector. Bioinsecticide developed from bacteria, virus, mushroom, and protozoa. Bacteria that often used to produce bioinsecticide is “Bacillus thuringiensis”. Bacillus thuringiensis subsp. aizawai (Bta) as one of the Bacillus thuringiensis (Bt) species produces crystal protein called delta endotoxin (δ-endotoxin). As other Bt crystal protein, this crystal is specifically toxic to larvae Lepidoptera and Dipteral ordo. One of advantage bioinsecticide Bta is savety for our environment. Therefore, in this research produce bioinsecticide Bta from waste of industrial tofu as raw material standard. This research was to obtain the best product formulations Bta, reduction quality Bta, and to asses the level of toxicity Bta during storage. Media formulation using tofu waste and tofu waste water, with a ratio of 20: 80 and the starter added 10 (% v /v). In this research, product formulation using lactose as filler. The highest viable spore count (VSC) is the product formulation of freeze lactose (1.45 x 108 spora/mg), whereas the lowest VSC is the product formulation of freeze without lactose (9.25 x 107 spora/mg). After storage one month, the highest VSC is product formulation of freeze lactose was storaged on temperature 5 oC (9 x 106 spora/mg), whereas the lowest VSC is the product formulation of freeze without lactose was storaged on temperature 35 oC (1.5 x 106 spora/mg. The level toxicity (LC50) product formulation of freeze lactose and freeze without lactose are 0.25 mg/l. Value of LC50 from all of the treatment higher than value of LC50 Bactospeine (0.05 mg/l). During storage one month, value of LC50 and potential product bioinsecticide Bta go down continually.
Keyword: 

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. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular