Judul: Soil Strength over Various Land Use and Slopes (Case Study: PT. Perkebunan Buah Subang)
Abstrak: Areal perbukitan dan pegunungan berpotensi mengalami longsor karena cenderung memiliki lereng yang curam. Terjadinya longsor erat kaitannya dengan kekuatan tanah. Kekuatan tanah merupakan parameter yang menggambarkan kemampuan tanah menahan tekanan tanpa mengalami kegagalan. Penelitian yang bertujuan untuk mengidentifikasi kekuatan tanah pada lahan terbuka, kebun bambu, dan hutan dengan kemiringan lereng berbeda, serta mengetahui hubungannya dengan sifat-sifat fisik dan kandungan bahan organik tanah, dan mengetahui pengaruh kehadiran perakaran tanaman terhadap kekuatan tanah telah dilakukan di daerah PT. Perkebunan Buah Subang. Penelitian dilakukan pada lahan terbuka, kebun bambu, dan hutan dengan kemiringan lereng 15-30% dan 30-45%. Parameter kekuatan tanah yang diukur di lapang adalah ketahanan penetrasi dan kekuatan geser tanah. Sifat-sifat fisik dan kandungan bahan organik yang mempengaruhi kekuatan tanah dianalisis di laboratorium. Kekuatan tanah berbeda-beda pada berbagai penggunaan lahan dan kemiringan lereng. Lokasi kebun bambu kemiringan lereng 15-30% dan 30-45% menunjukkan nilai kekuatan geser yang lebih tinggi dibandingkan lokasi lainnya. Kekuatan geser tanah pada lokasi kebun bambu lebih tinggi karena sistem perakarannya serabut yang terjalin satu sama lain dalam mengikat matrik tanah sehingga tanah menjadi lebih kuat dalam menahan keruntuhan. Ketahanan penetrasi dipengaruhi oleh kandungan bahan organik, jumlah diameter agregat paling besar (≥ 2 mm), bobot isi tanah, dan porositas total tanah. Semakin tinggi persentase diameter agregat berukuran ≥ 2 mm, kandungan bahan organik, dan porositas total, serta semakin rendah bobot isi tanah akan menyebabkan ketahanan penetrasi semakin rendah. Kekuatan geser dan ketahanan penetrasi tanah pada lokasi dengan penggunaan lahan kebun bambu, baik pada kemiringan lereng 15-30% maupun pada kemiringan lereng 30-45% menunjukkan adanya trend penurunan nilai pada jarak yang semakin menjauhi tanaman bambu. Kata kunci: jarak, kekuatan geser, ketahanan penetrasi, perakaran, sifat fisik., Hilly and mountainous areas have the potential to experience landslides because they tend to have steep slopes. The occurrence of landslides is closely related to soil strength. Soil strength is a parameter that describes the ability of the soil to withstand pressure without experiencing failure. A research aims at identifying soil strength in open land, bamboo gardens, and forests with different slopes, as well as to determine their relationship to soil physical properties and soil organic matter content, and knowing the effect of plant roots on soil strength was carried out in the area of PT. Perkebunan Buah Subang. The research was conducted on open land, bamboo gardens, and forests with slopes of 15-30% and 30-45%. Soil strength parameters measured in the field are penetration resistance and soil shear strength. Soil physical properties and organic matter content that affect soil strength are analyzed in the laboratory. Soil strength varies with different land uses and slopes. The location of the bamboo garden with a slope of 15-30% and a slope of 30-45% shows a higher shear strength value than other locations. The shear strength of the soil at the bamboo garden location is higher because the root system has fibers that intertwine with each other to bind the soil matrix so that the soil becomes stronger to resist collapse. Soil penetration resistance is influenced by soil organic matter content, the largest amount of soil aggregate diameter (≥ 2 mm), bulk
Keyword: Distance, soil shear strength, soil penetration resistance, roots, soil physical properties

Judul: Soil Strength in Three Different Slope of PT.  Perkebunan Buah Subang Bare Land
Abstrak: Kekuatan geser tanah ditentukan untuk mengukur kemampuan tanah menahan tegangan geser tanpa terjadi keruntuhan. Pengetahuan mengenai kekuatan geser tanah penting dipahami guna menyelesaikan persoalan praktis perihal potensi terjadinya pergerakan tanah akibat berbagai aktivitas pertanian. Penelitian ini bertujuan mengidentifikasi sifat fisik tanah yang berkaitan dengan nilai kekuatan tanah pada tiga kelas kemiringan lereng lahan terbuka. Pelaksanaan penelitian dilakukan pada tiga kelas lereng (15-30%, 30-45%, dan 45-65%) lahan terbuka pada kedalaman 0-20cm dan 20-40cm. Hasil penelitian menunjukkan kekuatan geser tanah dan ketahanan penetrasi pada kedalaman 0-20cm lebih rendah dibandingkan kedalaman 20-40cm di tiga kelas lereng lahan terbuka. Nilai rata-rata kekuatan geser tanah pada kedalaman 20-40 cm semakin meningkat seiring bertambahnya kemiringan lereng, sementara ketahanan penetrasi tidak mempunyai pola yang tetap. Nilai Kekuatan tanah meningkat seiring dengan semakin tinggi kandungan klei dan rendahnya bahan organik, Soil shear strength is the resistance of soil grains against pressure or pull. The knowledge about soil shear strength is important to solve practical problems regarding the potential of soil movement due to various agricultural activities. A research aims to identify the physical properties of soil related to the value of soil strength at three slope classes of bare land was conducted at PT. Perkebunan Buah Subang, Subang Regency, West Java. The research was carried out on three slope classes (15-30%, 30-45%, and 45-65%) of bare land at a depth of 0-20cm and 20- 40cm. The results showed that the soil shear strength and penetration resistance at a depth of 0-20cm are lower than those at a depth of 20-40cm in the three classes of bare land slopes. The average value of soil shear strength at a depth of 20-40cm increases as the slope increases. Meanwhile, the average penetration resistance showed no regular pattern. The value of soil strength increases as the higher the content of klei is, and the lower the organic matters content are.
Keyword: Organic matters, penetration resistance,, shear strength, soil movement

Judul: Pemurnian dan karakterisasi protein inhibitor RNA helikase virus hepatitis C
Abstrak: Hepatitis C virus (HCV) infection is the second most common chronic viral infection in the world with global prevalence. This infection is contribution to chronic hepatitis and liver cirrhosis, often leading to hepatocellular carcinoma. There is no effective drug and vaccine available against HCV. The current standard treatment, a combination of pegylated interferon-α with ribavirin, is limited by its suboptimal response rate in a significant patient population, side effects, and affordability. Therefore, development of effective drug is needed. One approach to find out the candidate of antiviral drug is to discover the inhibitor of enzyme that essential for virus replication, such as RNA helicase. Streptomyces chartreusis 5-095 produce the inhibitor of HCV RNA helicase. The aim of this study was to purify the protein inhibitor which has inhibition activity against ATPase activity of RNA helicase HCV from S. chartreusis 5-095. The supernatant of culture S. chartreusis 5-095 exhibited high inhibiton activity against ATPase activity of RNA helicase HCV (approximately 72%) at 10 days of incubation. The extracellular protein inhibitor was partially purified by procedures of precipitation with ammonium sulfate to 65% saturation and gel filtration (Sephadex G50) using methanol water solution (4:6) as an eluen. The purity of protein inhibitor was monitored by SDS PAGE. The protein inhibitor showed a relative molecular mass were estimated to be 14 kDa and increased the purity 23,08 fold than those of the crude protein. The specific activity and IC50 after purification were 13,1338 U/mg and 0,0767 mg/mL, respectively. The activity of purified protein inhibitor showed its stability over pH range from 5-8 and optimum at pH 7,4. The inhibition activity showed its stability up to 70% at temperature 100 oC. The purified protein inhibitor relatively stable its activity at storage in the range of -20 oC to room temperature for 35 days.
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