Judul: Coffee Grounds Composite as an Environmentally Friendly Heat-Resistant Material
Abstrak: Poli asam laktat (Polylactic Acid/PLA) merupakan polimer ramah lingkungan, namun penggunaan PLA sebagai material tahan panas masih kurang diminati karena lebih mahal dibandingkan polyolefin. Pencampuran PLA dengan Thermoplastic Starch (TPS) mampu mengurangi harga PLA namun sifat fisis, mekanis dan thermal komposit menurun. Pencampuran dengan sukrosa dan ampas kopi bertujuan untuk memperbaiki karakteristik dari komposit PLA-TPS (PT). Penelitian ini bertujuan untuk mengembangkan dan mengevaluasi sukrosa dan ampas kopi sebagai material komposit tahan panas yang dicampurkan dengan PLA dan TPS. Komposit dibuat dengan berbagai variasi kadar penambahan sukrosa (1,2,3 % b⁄b) dan ampas kopi (5,10,15 % b⁄b). Hasil penelitian menemukan bahwa karakteristik terbaik dihasilkan oleh ampas kopi pada kadar 5% dengan hasil: Water Vapor Transmission Rate (1276 g/m2.d), Water Vapor Permeable (1.86256×10-7 g/m.s Pa), modulus young (420 MPa), elongasi (2.59%) dan kuat tarik (5 MPa). Penambahan sukrosa dapat meningkatkan sifat fisis, mekanis dan thermal komposit PT sedangkan penambahan kopi dapat meningkatkan sifat thermal dan kristalinitas dari PT.
Keyword: Composite, Environmentally Friendly Composite, Polylactic Acid, Spent Coffee Ground, Thermoplastic Starch

Judul: Penguatan Sifat Mekanis Komposit Poliasam Laktat dan Selulosa Mikrofibril Terasetilasi-Terlaktilasi
Abstrak: The composites based on polylactic acid (PLA) reinforced with 10% modified microfibrillated cellulose (MFC) has been succesfully prepared. Modification of MFC was needed to increase its compatibility with PLA in the composite formation. In this experiment, MFC was modified with partial acetylation (degree of substitution: 1) and further grafted with lactide monomers through ring-opening polymerization. The result of acetylation and grafting were verified by infrared spectra. Thermal characterization carried out using differential scanning calorimetry measurements showed that the presence of modified MFC increased the temperature of glass transition and accelerated the crystallization of PLA. In addition, mechanical properties measurements showed that the modified MFC formed percolation network and acted as a fillers within the PLA matrix. It was showed by enhancement in elongation at break (1.1% to 1.8%), tensile strength (14.9 MPa to 25.7 MPa), and modulus of elasticity (1.7 GPa to 2.1 GPa).
Keyword: polylactic acid., partial acetylation, microfibrillated cellulose, lactide grafting

Judul: Mitochondrial DNA Gene Organization and Phylogenetic Relationship of Naja siamensis
Abstrak: Naja siamensis is one of Asiatic cobra in the Family of Elapidae, known as a cryptic snake. It has many morphological variations that lead to misidentification. Misidentification can cause the wrong concept in developing antivenom types due to high snakebite cases occur in Thailand. Thus, an accurate species identification using a molecular approach is crucially required. Mitochondrial DNA has been used widely in snake molecular studies. These studies were aimed to determine the arrangement of the N. siamensis partial mitochondrial genes using reptile-oriented primers and to reveal the phylogenetic relationship among other species of Asian cobra. DNA extraction was carried out based on the standard DNA salting-out protocol and was conducted by bioinformatics analysis using BLASTn and MEGA 6 software. Gene annotation was performed against N. kaouthia complete genome. A total of 3121 bp of N. siamensis mtDNA genes were sequenced consisting of partial of six regions: 16S rRNA, ND1, tRNA-Ile, CRII region, tRNA-Leu, tRNA-Gln, and COI genes. The mtDNA gene organization of N. siamensis was predicted to has a similar pattern with the common Elapidae mtDNA gene organization. This study showed that there is a monophyletic form in Naja genus and N. kaouthia is the closest species with N. siamensis based on partial 16S rRNA and ND1 gene.
Keyword: 16S rRNA, Elapidae, ND1, phylogenetic relationship