Judul: Identifikasi faktor-faktor yang mempengaruhi status anemia pada ibu hamil menggunakan metode CHAID dan RANDOM FOREST
Abstrak: Anemia pada ibu hamil merupakan salah satu masalah yang dihadapi oleh masyarakat. Tingginya angka anemia ibu hamil sejalan dengan kurangnya kesadaran terhadap pentingnya mengkonsumsi makanan yang bergizi terutama zat besi pada ibu hamil. Hal yang dapat dilakukan untuk menanggulangi masalah anemia pada ibu hamil adalah dengan mengklasifikasikan faktor-faktor yang berhubungan dengan status anemia pada ibu hamil. Metode CHAID (Chisquare Automatic Interaction Detection) merupakan salah satu metode yang membahas masalah klasifikasi yang diterapkan pada data yang bertipe kategorik untuk peubah responnya. Metode CHAID diterapkan pada delapan (8) peubah penjelas yang digunakan pada penelitian ini dengan pengulangan sebanyak tiga kali sehingga diperoleh perbedaan hasil pohon klasifikasinya. Perbedaan hasil klasifikasi dengan metode CHAID mengakibatkan ketidakstabilan peubah pencirinya, oleh karena itu dilanjutkan dengan metode random forest untuk melihat peubah penciri yang stabil. Metode random forest menghasilkan tiga peubah penjelas yang stabil secara berurutan adalah lingkar lengan atas (lila), frekuensi pemeriksaan kehamilan (anc), dan umur klinis ibu hamil. Peubah penciri hasil random forest diterapkan pada metode CHAID untuk melihat klasifikasinya. Metode CHAID dengan kriteria random forest menghasilkan kriteria ibu hamil yang cenderung anemia ketika ukuran lingkar lengan atas (lila) kurang dari 23.5 cm dan pemeriksaan kehamilan kurang atau sama dengan empat kali, sedangkan kriteria tidak anemia ketika ukuran lingkar lengan atas (lila) lebih besar atau sama dengan 23.5 cm dan melakukan pemeriksaan kehamilan (anc) lebih dari satu kali.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, Anemia, Maternal, CHAID, RANDOM FOREST

Judul: Identifikasi Faktor-Faktor yang Mempengaruhi Status Anemia pada Ibu Hamil Menggunakan Metode CHAID dan Random Forest
Abstrak: Maternal anemia is one of problem in society. The high rates of maternal anemia in line with lack of awareness to iron consumption. The solution for this problem is classifiying the factors associated with maternal anemia status. CHAID method (Chisquare Automatic Interaction Detection) is one of classification method which type categorical response variable. In this study, CHAID method applied to eight explanatory variable with repetition three times so that the resulting classification tree is different. Differences in classification result with the CHAID method lead to instability identifier variable therefore proceed with the random forest method to see identifier variable that stable. Random forest produced three explanatory variables sequentially stable are upper arm circumference (lila), frequency of prenatal care (anc), and maternal age clinical. Identifier variable be produced random forest method applied to the CHAID method to see its classification. CHAID method with random forest criteria produce that maternal anemia criteria if maternal upper arm circumference (lila) less than 23.5 cm and frequency of prenatal care (anc) less than four times, where as maternal normal if maternal upper arm circumference (lila) more than 23.5 cm and frequency of prenatal care (anc) more than one.
Keyword: anemia, maternal, CHAID, random forest

Judul: Extracellular Expression of thermostable Geobacillus stearothermophilus T1.2RQ Lipase for Biodiesel Production
Abstrak: The extracellular expression of enzymes in an excellent secretion host such as Bacillus subtilis is a useful strategy for making enzymes of industrial significance more affordable by lowering the cost of its downstream processing. Lipases are a category of hydrolases that catalyze the hydrolysis of triglycerides to glycerol and free fatty acids. Also, lipases catalyze the hydrolysis and transesterification of other esters as well as the synthesis of esters. They can perform very specific biotransformation reactions and are widely used in food, organic synthesis, detergents, cosmetic, and pharmaceutical industries. Geobacillus stearothermophilus T1.2RQ lipase is an industrially-desired thermostable lipolytic enzyme with an excellent hydrolytic and transesterification activity. This study aimed to express T1.2RQ lipase, in B. subtilis WB800 and ensure its secretion into the extracellular medium. Three signal peptides (AmyQ, Epr, LipA) and two promoters (Pgrac01 and Pgrac100) were used in the secretory-expression of T1.2RQ lipase, based on five constructed expression vectors constructed by restriction cloning and PCR mutagenesis. Sangers sequencing was used to verify constructs to ensure they are in the correct reading frame. Recombinants vectors, pHT43 (plasmid control), pHT43-T1.2RQ, pHT43- T1.2RQ_AmyQ, pHT43-T1.2RQ_Epr, and pHT43-T1.2RQ_LipA, were transformed by electroporation into Bacillus subtilis WB800. The electroporation was successful with the optimum condition of 2500V, 200 ohms, 25µF, and 5milliseconds. Recombinant B. subtilis pHT43 (negative control) and pHT43-T1.2RQlip + signal peptides were streaked on the lipidic agar, LA+TBN. All four recombinants, including the negative control (B. subtilis WB800-pHT43), produced clear zones on the TBN agar plate after overnight incubation (fig 2), indicating the presence of a lipolytic enzyme in all of the recombinant B. subtilis cells. pHT43-T1.2RQlip + signal peptides (AmyQ, Epr, and LipA) have clear zones with significantly higher diameters than B. subtilis WB800-pHT43 (negative control). This phenomenon suggests that the recombinant thermostable lipase T1.2RQ introduced into these cells was successfully expressed, thereby increasing the lipolytic capability of its host cells T1.2RQ lipase was expressed in 50ml terrific broth medium (TB) and the expression induced with 1mM IPTG. Lipase activity assay using p-nitrophenyl esters showed that all three signal peptides directed the secretion of T1.2RQ lipase into the extracellular medium. Signal peptide, LipA, resulted in the highest extracellular activity of 5.6 U/mL, which corresponds to a 6-fold increase over the parent B. subtilis WB800 strain. Meanwhile, signal peptides, AmyQ and Epr produced 4.2 U/mL and 3.4 U/mL activity respectively. SDS-Zymogram analysis confirmed that T1.2RQ lipase was correctly processed and secreted in its original size of 44 kDa. An attempt to further increase lipase expression level by promoter optimization showed that, contrary to expectation, promoter Pgrac100 exhibited similar expression levels as the original Pgrac01. Nevertheless, the demonstration of the successful secretion of T1.2RQ lipase in this work confirms the latter as a promising approach for the industrial production of the enzyme
Keyword: Bacillus subtilis, Expression, Extracellular, Heterologous, Lipase, Thermostable