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: Aktivitas Antibakteri dan Sediaan Masker Peel Off Berbahan Spirulina platensis terhadap Bakteri Propionibacterium acne.
Abstrak: Spirulina platensis merupakan mikroalga kelompok cyanobacteria yang mengandung senyawa aktif dan berpotensi sebagai antibakteri. Tujuan penelitian ini yaitu menentukan aktivitas antibakteri terhadap P. acne dari ekstrak S. platensis kultur dan komersial, serta sediaan masker peel off yang mengandung ekstrak dan biomasa S. platensis. Tahapan penelitian meliputi kultivasi, pemanenan S. platensis, ekstraksi senyawa aktif, dan aplikasi S. platensis sebagai sediaan masker peel off berbahan polivinil alkohol, hydroxy propyl methyl cellulose, metil paraben, gliserin serta analisis aktivitas antibakteri. Kultivasi S. platensis menggunakan media organik. Biomasa S. platensis diekstraksi menggunakan etanol PA 96%, selanjutnya dianalisis fitokimia. Analisis aktivitas antibakteri dilakukan dengan ekstrak S. platensis dan sediaan masker peel off. Aktivitas antibakteri ekstrak S. platensis hasil kultur dengan konsentrasi 2 mg/mL, 4 mg/mL dan 8 mg/mL berturut-turut yakni 4.63±0.35 mm, 8.81±0.08 mm, 9.56±0.26 mm, sedangkan aktivitas antibakteri dalam sediaan masker peel off terhadap bakteri P. acne yakni 10±0.35 mm.
Keyword: antibakteri, organik, Propionibacterium acne, Spirulina platensis

Judul: Real Option Valuation Using Binomial Decision Trees.
Abstrak: A firm that decides to invest has a choice to invest in real assets. A method which is usually used in valuation of the project is discounted cash flow (DCF) method. But, this method can’t be used in projects that account for value of managerial flexibility, such as decision to suspend operations temporarily. Therefore, this kind of project needs to be assessed using real option. Real option valuation can be done in some ways, including the use of path-dependent simulation, as well as closed-form models like Black-Scholes model, partial differential equation, and binomial or multinomial approaches. In this paper, real option valuation using binomial decisions id discussed. Determination of the project value can be done in three steps. First, calculate the expected present value of the project. Next, calculate volatility of the project using Monte Carlo simulation. Last, construct a binomial tree to model the dynamics of the project value using the parameters of the stochastic process, and then add some decision nodes to model the project’s real options.
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