Judul: Aktivitas antioksidan dan analisis komposisi senyawa fenolik dari pohon bidara laut (Strychnos ligustrina)
Abstrak: The bidara laut (Strychnos ligustrina) exhibits antioxidant activity. The objective of this study is to determine the highest antioxidant activity, total phenol, and bioactive compound analyzed using gas chromatography-mass spectrometer (GCMS) of the extract of bidara laut tree. Antioxidant activities was determined by radical scavenging assay using 1,1-diphenyl-2-pycryl-hydrazyl radical. The result showed that the highest of antioxidant activities is the wood methanol extract with IC50 value of 148.14 mg L-1. After partition using n-hexane the IC50 value was 103.14 mg L-1 and of butyl hydroxyl toluene which was used as control positive showed IC50 value of 10.86 mg L-1. The total phenol was determined using Folin-Ciocalteau method and resulted 1936.844 mg kg-1 dry sample. The result of compound analysis using GCMS showed that bidara laut contain phenolics with the major content is 1,2,3-benzenetriol, which is 2.66% (RT 10.77).
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Judul: Aktivitas Antimalaria Ekstrak Kayu Bidara Laut (Strychnos ligustrina Blume)
Abstrak: Kayu bidara laut (Strychnos ligustrina Blume) telah lama dimanfaatkan sebagai salah satu obat antiimalaria oleh masyarakat Indonesia. Tujuan dari penelitian ini telah menentukan ekstrak dan aktivitas antimalaria ekstrak kayu bidara laut serta identifikasi terhadap ekstrak teraktif. Ekstrak kayu bidara laut diperoleh menggunakan pelarut n-heksana, etil asetat, dan etanol secara berurutan. Ekstrak kemudian diuji pada parasit Plasmodium falciparum secara in vitro. Komponen kimia dari ekstrak teraktif kemudian dianalisa menggunakan analisis kualitatif fitokimia dan gas kromatografi spektroskopi massa (GCMS). Hasil penelitian menunjukan rendeman n-heksana, etil asetat dan etanol secara berturut 0.62%, 0.66%, dan 4.23%. Ekstrak yang menunjukan aktivitas malaria untuk menghambat pertumbuhan parasit P. falciparum yaitu ekstrak etanol dengan nilai IC50 3.09 ug/mL. Ekstrak etanol terdeteksi terdiri atas golongan alkaloid, flavonoid, fenol hidroquinon dan tanin. Pada ekstrak etanol terdeteksi 28 senyawa dimana salah satunya adalah strychnine yang diketahui memiliki aktivitas antimalaria
Keyword: aktivitas antimalaria, ekstrak kayu, Plasmodium  falciparum, Strychnos ligustrina

Judul: Model Input-output dalam Masalah Network Flow
Abstrak: Production process is a process, which is done by industry, to transform input into output. According to the type of output and its activity, industry can be classified into various sectors, which are connected to each other. Therefore, a model to analyze the connection among sections is needed. The model is known as input-output model (IO model). IO model presents an IO table, which shows informations about the transaction between goods and services in each economic sector. Furthermore, the IO model also shows that the amount of all input is the same as the amount of all output. In this paper, the transaction of each economic sector in IO table is analyzed using network flow theory. The formulated network flow problem implies that each sector represents partly as a producer and also as a consumer. This paper also solves a minimum cost circulation problem.
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