Judul: Pemetaan Perubahan Garis Pantai di Pesisir Manggar, Belitung Timur dengan Menggunakan Citra Sentinel-2A
Abstrak: Wilayah pesisir merupakan wilayah yang paling rentan terhadap perubahan karena masih dipengaruhi interaksi dari daratan dan lautan yang bergerak secara terus-menerus, seperti aktivitas arus dan gelombang yang dibangkitkan oleh angin, serta pasang surut. Perubahan garis pantai dianalisis menggunakan teknologi pengindraan jauh yang memiliki kemampuan khusus untuk menangani daya yang bereferensi keruangan (spasial) dalam waktu yang singkat terkait fenomena yang ada dimuka bumi. Penelitian ini bertujuan memetakan dan mengetahui laju perubahan garis pantai yang disebabkan oleh proses abrasi dan akresi di pesisir Kecamatan Manggar, Kabupaten Belitung Timur, Bangka Belitung, dengan menggunakan citra Sentinel-2A pada tahun 2015 – 2023. Metode Digital Shoreline Analysis System (DSAS) digunakan untuk menghitung jarak dan laju perubahan garis pantai secara statistik maupun geospasial, melalui Net Shoreline Movement (NSM) dan End Point Rate (EPR). Lokasi penelitian terbagi menjadi 11 sub-zona, yang mencakup 4 pantai di Belitung Timur. Abrasi tertinggi terjadi di Desa Lalang (sub-zona D2) dengan jarak kemunduran garis pantai sejauh 65,38 m dan laju kemundurannya 8,78 meter/tahun. Akresi tertinggi terjadi di Desa Baru (sub-zona B2) dengan jarak kemajuan garis pantai sejauh 56,68 m dan laju kemajuannya 7,61 meter/tahun. Kondisi abrasi dan akresi pesisir Manggar dipengaruhi oleh faktor darat dan laut, seperti sedimentasi muara sungai, topologi pantai yang berpasir dan landai, serta kondisi geografi Belitung Timur yang termasuk perairan terbuka., Coastal areas are extremely vulnerable to change due to the continuous interaction between land and ocean, including current and wave activity generated by wind and tides. Remote sensing technology is a powerful tool used to analyze shoreline changes, capable of quickly handling spatially-referenced data related to phenomena on Earth. This study confidently maps and determines the shoreline change rate caused by abrasion and accretion processes on the coast of Manggar Subdistrict, East Belitung Regency Bangka Belitung, using Sentinel-2A images from 2015 to 2023. The Digital Shoreline Analysis System (DSAS) method was applied with statistical and geospatial calculations using Net Shoreline Movement (NSM) and End Point Rate (EPR) to accurately calculate the distance and rate of shoreline change. The research site was divided into 11 sub-zones, covering 4 beaches in East Belitung. Lalang Village (D2) experienced the highest abrasion, with a shoreline retreat distance of 65.38 meters and a retreat rate of 8.78 meters/year. On the other hand, Baru Village (B2) saw the highest accretion, with a shoreline advance distance of 56.68 meters and an advance rate of 7.61 meters/year. Both land and sea factors influence Manggar coast abrasion and accretion. These factors comprise the sedimentation of river estuaries, sandy and sloping coastal topology, and the geography of East Belitung, which includes open waters.
Keyword: abrasion, accretion, DSAS, East Belitung

Judul: Detection of Shoreline Changes in Manggar District, East Belitung Using Landsat Imagery
Abstrak: Perairan pantai Kecamatan Manggar, Belitung Timur merupakan perairan terbuka sehingga parameter oseanografi seperti arus dan gelombang berpengaruh langsung terhadap perubahan garis pantai. Pantai Manggar terdiri dari pantai berpasir dan berbatu dengan kemiringan yang landai. Beberapa lokasi di Pantai Manggar rentan terhadap abrasi dan akresi. Deteksi garis pantai menggunakan Citra Landsat dilakukan untuk mengetahui perubahan garis pantai yang terjadi dari tahun 1991 – 2021. Metode Digital Shoreline Analysis System (DSAS) digunakan untuk menghitung statistik laju perubahan garis pantai. Metode yang digunakan adalah Net Shoreline Movement (NSM) dan End Point Rate (EPR). Kecepatan angin tertinggi terjadi pada musim timur yang mencapai 5.61 m/s dan terendah pada musim peralihan I yang hanya mencapai 0.59 m/s. Arus dengan kecepatan tertinggi adalah 0.88 m/s pada musim barat, terendah terjadi pada musim peralihan I sebesar 0.03 m/s. Kondisi gelombang pada musim timur merupakan yang paling tinggi mencapai 0.75 meter di sekitar area kajian dan terendah pada musim peralihan I dengan tinggi 0.21 meter. Pasang surut di Kecamatan Manggar bertipe diurnal dan memiliki nilai Mean Sea Level (MSL) 1.25 meter. Jarak abrasi terjauh terdapat di Pantai Mudong, Desa Padang yang mencapai 127.8 meter dalam 30 tahun. Akresi paling besar terjadi di Pantai Serdang, Desa Kurnia Jaya pada wilayah yang berdekatan dengan bagian hilir sungai, penambahan garis pantai mencapai 128.4 meter., The coastal waters of Manggar District, East Belitung are open waters so that oceanographic parameters such as currents and waves have a direct effect on changes in the coastline. Manggar Beach consists of sandy and rocky beaches with a gentle slope. Some locations in Manggar Beach are prone to abrasion and accretion. Coastline detection using Landsat Imagery was carried out to determine coastline changes that occurred from 1991 – 2021. The shoreline changes were calculated using the Digital Shoreline Analysis System (DSAS) with the Net Shoreline Movement (NSM) and End Point Rate (EPR) methods. The highest wind speed occurred in the east monsoon which reached 5.61 m/s and the lowest in the first transitional season which only reached 0.59 m/s. The current with the highest speed was 0.88 m/s in the west monsoon, the lowest occurred in the first transitional season of 0.03 m/s. Wave conditions in the east monsoon were the highest reached 0.75 meters around the study area and the lowest in the first transitional season with a height of 0.21 meters. The tides in Manggar Subdistrict were of diurnal type and Mean Sea Level (MSL) value of 1.25 meters. The farthest abrasion distance was found in Mudong Beach, Padang Village which reached 127.8 meters in 30 years. The greatest accretion occurred at Serdang Beach, Kurnia Jaya Village in the area adjacent to the downstream of the river, the addition of coastline reaches 128.4 meters.
Keyword: Accretion, Abrasion, DSAS, Landsat

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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