Judul: Aktivitas antibakteri Spirulina platensis terhadap bakteri penyebab jerawat dan karakteristik masker berbasis Spirulina dan kolagen.
Abstrak: Penelitian ini menggunakan Spirulina yang dikultur dalam media media organik (pupuk Urea, Plant Catalyst dan RI1) dan kolagen dari kulit ikan kakap merah. Tujuan penelitian menentukan karakteristik Spirulina, karakteristik kolagen serta karakteristik fisik, kimiawi dan mikrobiologis sediaan masker. Tahapan penelitian meliputi kultivasi dan pemanenan S. platensis, ekstraksi biomasa menggunakan etanol, ekstraksi kolagen menggunakan pelarut NaOH dan asam asetat serta formulasi masker. Analisis meliputi fitokimia, rendemen, aktivitas antibakteri, analisis sensori, homogenitas, viskositas, daya sebar dan total mikroba. Ekstrak S.platensis mampu menghambat bakteri penyebab jerawat Staphylococcus aureus, Stapylococcus epidermidis serta Propionibacterium acne dengan diameter zona hambat terbesar pada ekstrak 100 μg/sumur. Kolagen ikan kakap berwarna putih, dengan rendemen sebesar 6.4±0.28%, dan pH 6.46±0.15. Sediaan masker yang dihasilkan memiliki nilai sensori berkisar 3.57- 4.23 dalam kategori suka, homogen, daya sebar 6.6±0.28, viskositas 2500±70.71, pH 6.29±0.06, dan total mikroba <1x10 cfu/g. Sediaan masker mampu menghambat bakteri penyebab jerawat S. aureus, S. epidermidis serta P. acne.
Keyword: antibakteri, kolagen, masker, Spirulina platensis

Judul: Characteristics of peel off mask made from Spirulina and collagen during storage in different packages
Abstrak: Masker berbahan Spirulina dan kolagen ikan memiliki aktivitas antibakteri terhadap bakteri penyebab jerawat. Lingkungan dapat memengaruhi karakteristik masker, sehingga diperlukan pengemasan. Tujuan penelitian ini menentukan pengaruh perbedaan kemasan terhadap karakteristik fisik, kimia, dan mikrobiologis masker selama penyimpanan. Masker dalam penelitian ini disimpan dalam kemasan round jar, alumunium foil sachet, dan tube pada suhu ruang selama 28 hari dengan analisis data menggunakan analisis ragam Rancangan Acak Lengkap Faktorial (RALF). Masker dalam ketiga kemasan selama penyimpanan 28 hari memiliki nilai sensori yang tidak mengalami perubahan, yaitu berwarna hijau pekat, tidak berbau, konsistensi kental, dan homogen. Faktor jenis kemasan dan lama penyimpanan berpengaruh nyata (p<0.05) terhadap nilai pH masker, waktu mengering masker, viskositas, kadar air, dan kelembaban kulit, dengan nilai yang masih sesuai dengan persyaratan mutu masker yang baik. Masker dalam kemasan terpilih alumunium foil sachet selama penyimpanan 28 hari memiliki nilai total mikroba yang masih sesuai dengan persyaratan masker yang baik yaitu sebesar <1.0x102 CFU/g., Masks made from Spirulina and fish collagen have antibacterial activity against acne-causing bacteria. The environment can affect the characteristics of masks, therefore the packaging is necessary. The purpose of this research was to determine the effect of different packaging on the physical, chemical, and microbiological characteristics of mask during storage. The masks in this research were stored in round jar, alumunium foil sachet and tube at room temperature for 28 days. A completely randomized factorial design was used in this study. The sensory values of the three masks did not change after 28 days such as in its color, odor, and consistency. The physical characteristics were dark green color, odorless, thick consistency, and homogenous. The type of packaging and storage time had a significant effect (p<0.05) on the pH values of the mask, mask drying time, viscosity, moisture content, and skin moisture, with values that were still in accordance with the requirements for good quality masks. The masks in the selected aluminum foil sachets for 28 days of storage have a total microbial value that is still in accordance with the requirements of a good mask, namely <1.0x102 CFU/g.
Keyword: packaging, collagen, mask, Spirulina

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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