Judul: Sonication Time Effect and Coating Against Particle Size and Magnetization Saturation of Nanoparticle Magnetite  Fe3o4
Abstrak: Magnetit adalah mineral ferrimagnetik yang pada umumnya dapat disintesis menggunakan metode kopresipitasi. Kegunaannya dalam dunia medis dan industri menjadikan magnetit sebagai pusat perhatian para peneliti. Oleh karena itu penting adanya informasi mengenai metode paling efektif dalam memperoleh magnetit dengan karakteristik tersendiri. Pada penelitian ini dilakukan penelaahan terhadap 26 sumber pustaka. Berdasarkan data analisis XRD yang telah dikumpulkan, magnetit hasil ultrasonikasi cenderung memiliki ukuran lebih kecil daripada yang disintesis tanpa ultrasonikasi. Ukuran terkecil partikel dibatasi oleh kemampuan material tersebut dalam memerangkap gelombang ultasonik sebelum pecah menjadi lebih kecil. Selain itu penambahan konsentrasi coating terbukti dapat memperkecil ukuran partikel, hal ini disebabkan penambahan coating menjadikan material yang disintesis menjadi lebih stabil sehingga pengaruh ultrasonikasi dapat berlangsung lebih efektif. Namun di sisi lain, penambahan coating justru mengurangi nilai saturasi magnetisasi., Magnetite is a ferrimagnetic mineral that can generally be synthesized using the coprecipitation method. Its medical and industrial uses have made magnetite the center of attention of researchers. Therefore it is important to have information about the most effective method of obtaining magnetite with its characteristics. In this study, 26 literature sources were reviewed. Based on the XRD analysis data that has been collected, the ultrasonicated magnetite tends to be smaller in size than those synthesized without ultrasonication. The smallest particle size is limited by the ability of the material to trap ultrasonic waves before breaking into smaller ones. Besides, the addition of coating concentration is proven to reduce the particle size, this is due to the addition of a coating to make the material being synthesized more stable so that the effect of ultrasonication can take place more effectively. But on the other hand, the addition of coating reduces the magnetization saturation value.
Keyword: Kopresipitasi, Magneti, Nanopartikel, Ultrasonikasi

Judul: Konsentrasi Sukrosa dalam Sintesis Nanomagnetit Fe3O4 dan Pendispersiannya dalam Larutan Polivinil Pirolidon
Abstrak: Nanomagnetit merupakan salah satu nanopartikel yang memiliki peluang aplikasi sangat luas. Penelitian ini bertujuan menentukan pengaruh kadar sukrosa terhadap ukuran nanomagnetit serta menguji stabilitas nanomagnetit dengan tambahan polivinil pirolidon (PVP). Nanomagnetit disintesis menggunakan metode hidrotermal pada suhu 200 ºC selama 12 jam. Berdasarkan hasil spektrum ultraviolet-sinar tampak, panjang gelombang maksimum larutan hasil sintesis adalah 273 nm (NM-1), 272.5 nm (NM-2), dan 273 nm (NM-3). Analisis difraksi sinar X menunjukkan fase kristalit yang terbentuk adalah magnetit dengan derajat kristalinitas 58.59% (NM-1), 24.44% (NM-2), dan 23.81% (NM-3). Spektrum inframerah dan spektrum energi dispersi menunjukkan terdapat produk reaksi sukrosa yang melapisi permukaan magnetit. Distribusi ukuran nanomagnetit 18.17-68.06 nm. Magnetit hasil sintesis berukuran nanometer dengan morfologi bulat tidak beraturan dan beraglomerasi. Semakin tinggi konsentrasi sukrosa yang digunakan, ukuran partikel semakin kecil, tetapi derajat kristalinitas semakin menurun. Nanomagnetit cenderung lebih stabil ketika didispersikan dalam polivinil pirolidon.
Keyword: asam glukonat, dispersi, nanomagnetit, PVP, sukrosa

Judul: Lejeuneaceae Subfamily Ptychanthoideae (Hepaticae) in  West Java
Abstrak: Subfamily Ptychanthoideae of the family Lejeuneaceae (Hepaticae) in West Java is still poorly known. Publications on this subfamily are out of dated and written in the 19th or early of 20th century. The last taxonomic treatment of Ptychanthoideae of West Java was in 1933, many species names have changed since then. Studies on Ptychanthoideae of West Java are urgently needed. Studies on the Ptychanthoideae were based on the specimens collected from West Java. A total number of 361 of specimens deposited in the Herbarium Bogoriense (BO), Herbarium Biotrop (BIOT), Gottingen Herbarium (GOET) and Bangi Herbarium (UKMB) were examined, those are old and several recent specimens collected in West Java. Recent collections were made from Telaga Warna, Ciater, Gunung Halimun Salak National Park, Cibodas Botanical Garden, Bodogol Education Center and Conservation (Gunung Gede Pangrango National Park), University of Indonesia Campus Depok, including several collections from Banten Province. Twenty four species of Lejeuneaceae subfamily Ptychanthoideae are known from West Java, belonging to 8 genera namely Acrolejeunea (Spruce) Schiffn. (2 species), Archilejeunea (Spruce) Schiffn. (1 species), Lopholejeunea (Spruce) Schiffn. (10 species), Mastigolejeunea (Spruce) Schiffn. (3 species), Ptychanthus Nees (1 species), Schiffneriolejeunea Verd. (1 species), Spruceanthus Verd. (2 species) and Thysananthus Lindenb. (4 species). Two new records of Ptychanthoideae: Mastigolejeunea indica Steph. and Thysananthus minor Verdoorn are reported for Java. A determination key to the species is presented including their descriptions and illustrations.
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