Judul: Sintesis dan Karakterisasi Nanopartikel ZnO dengan Variasi Suhu Kalsinasi dan Penambahan Surfaktan menggunakan Metode Kopresipitasi Kimia
Abstrak: ZnO merupakan oksida logam yang memiliki karakteristik yang menarik dengan energi celah pita yang lebar. Penelitian ini bertujuan menyintesis ZnO dengan metode kopresipitasi dan mengkarakterisasi menggunakan berbagai instrumentasi. Perlakuan variasi suhu kalsinasi dilakukan agar dihasilkan partikel dengan ukuran dan tingkat kristalinitas yang baik. Penambahan surfaktan polivinil pirolidon (PVP) pada saat sintesis ZnO bertujuan mencegah terjadinya aglomerasi. Karakterisasi ZnO menggunakan spektroskopi ultraviolet-tampak (UV-Vis), difraksi sinar-X (XRD), spektroskopi inframerah transformasi fourier (FTIR), dan mikroskop elektron pemayaran (SEM). Hasil penelitian menunjukkan bahwa nilai celah pita ZnO meningkat seiring dengan kenaikan suhu. ZnO yang disintesis pada suhu kalsinasi 800 °C memiliki struktur wurtzit heksagonal. Ukuran kristal ZnO adalah 45,64 nm, sedangkan ZnO-PVP sebesar 40,37 nm. Tingkat kristalinitas ZnO terbaik adalah 61,34%. Spektrum FTIR menunjukkan serapan ZnO pada daerah sidik jari. Mikrograf SEM memperlihatkan bahwa ZnO tanpa penambahan PVP mengalami aglomerasi. ZnO hasil sintesis menunjukkan aktivitas antibakteri dengan terbentuknya zona hambat., ZnO is a metal oxide that has special characteristics with a wide band gap energy. This study aims to synthesize ZnO by coprecipitation method and to characterize it using various instrumentation techniques. The calcination temperature variation treatment was carried out in order to produce particles with good size and crystallinity level. The addition of polyvinyl pyrrolidone (PVP) surfactant during the synthesis of ZnO aims to prevent agglomeration. ZnO characterization used visible- ultraviolet spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform spectroscopy (FTIR), and scanning electron microscopy (SEM). The result showed that the value of the ZnO band gap increased with increasing temperature. ZnO synthesized at a calcination temperature of 800 °C has a hexagonal wurtzite structure. The crystal size of ZnO is 45,64 nm, while that of ZnO-PVP is 40,37 nm. The best ZnO crystallinity level is 61,34%. The FTIR spectrum shows ZnO absorption in the fingerprint region. SEM micrographs showed that ZnO without the addition of PVP agglomerated. The synthesized ZnO has antibacterial activity which is indicated by the formation of an inhibition zone.
Keyword: antibacterial, coprecipitation, polyvinyl pyrrolidone, temperature, ZnO

Judul: Synthesis and Characterization of ZnO Nanoparticle and Its Encapsulation
Abstrak: Metode hidrotermal umum digunakan untuk menyintesis nanopartikel ZnO karena dapat menghasilkan produk dengan kristalinitas dan kemurnian yang tinggi. Namun, metode tersebut relatif membutuhkan waktu yang lama. Penelitian ini menggabungkan metode hidrotermal dan presipitasi untuk menghasilkan ZnO dalam waktu yang lebih singkat. ZnO juga disintesis menggunakan capping agent untuk mengontrol ukuran partikelnya lebih kecil yang terbukti dengan lamanya pengendapan partikel tersebut. Nanopartikel ZnO yang dihasilkan dapat diaplikasikan pada produk makanan dan minuman karena dapat memenuhi kebutuhan tubuh akan Zn dan berperan sebagai antibakteri yang bermanfaat untuk tubuh. Namun, ZnO masih memiliki bioavailibilitas dan kelarutan dalam air yang rendah serta sensitif terhadap degradasi kimia. Masalah-masalah tersebut dapat diatasi dengan mengenkapsulasi ZnO dalam material yang edibel seperti pektin dan yogurt. Kedua material tersebut berinteraksi secara elektrostatik membentuk kompleks penyalut untuk mengenkapsulasi ZnO. Partikel ZnO dapat dienkapsulasi dengan perlakuan pemanasan pada proses enkapsulasi yang dibuktikan dengan tidak munculnya puncak Zn-O pada spektrum FTIR., The hydrothermal method is commonly used to synthesize ZnO nanoparticles because it produces products with high crystallinity and purity. However, this method is relatively time-consuming. This research combines hydrothermal and precipitation methods to produce ZnO in a shorter time. ZnO was also synthesized using a capping agent to control the smaller particle size as confirmed by the aging time needed to precipitate the particles. The synthesized ZnO nanoparticles can be added to food and beverage products as zinc additives and antibacterial agents which are beneficial to the body. However, ZnO still has low bioavailability and water solubility and is sensitive to chemical degradation. These problems can be solved by encapsulating ZnO in edible materials such as pectin and yogurt. The two materials interact electrostatically to form a coating complex to encapsulate ZnO. ZnO particles can be encapsulated through heating treatment in the encapsulation process as confirmed by the absence of Zn-O peaks on the FTIR spectrum.
Keyword: encapsulation, nanoparticle, pectin, yogurt, ZnO

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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