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"Predictions of sensonal changes in N2O emission that occur in natural estuaries are important to anticipate the future implications of global warming....."

"Keragaman dan Komposisi Asam Lemak Bakteri Lipolitik Isolat Asal Tanah dan Sedimen Perairan Wilayah Hutan dan Perkebunan Sawit. Bakteri spesifik dalam hutan dan perkebunan kelapa sawit adalah bakteri lipolitik. Enzim-enzim dari bakteri lipolitik telah diaplikasikan di agro-akuakultur, makanan, deterjen, farmasi, industri susu, dan biodiesel-biokerosin. Penelitian bertujuan memberikan informasi keragaman bakteri lipolitik asal tanah dan sedimen perairan di areal hutan dan perkebunan kelapa sawit, dan komposisi asam lemaknya. Sampel tanah berasal dari tanah lapisan atas hutan dataran rendah dan perkebunan kelapa sawit dan sedimen air tawar di dekat situs tersebut. Hutan tersebut terletak di Taman Nasional Bukit Duabelas dan perkebunan kelapa sawit sekitarnya di Kabupaten Sarolangun, Jambi, Indonesia. Sebanyak 22 isolat terpilih dari tiga puluh dua isolat bakteri lipolitik yang tumbuh pada media selektif lipolitik, terdiri dari 11 isolat dari tanah lapisan atas dan 11 isolat dari sedimen air di hutan dan daerah perkebunan. Isolat-isolat bakteri diidentifikasi berdasarkan analisis gen 16S rRNA. Hasil identifikasi menunjukkan isolat-isolat tersebut terdiri atas lima genera yaitu Burkholderia, Cupriavidus, Serratia, Acinetobacter, dan Kurthia. Pada pohon filogenetik yang dibangun menggunakan metode maximum likelihood isolat-isolat tersebut terdistribusi ke dalam tiga grup, yaitu grup Burkholderia-Cupriavidus, grup Serratia-Acinetobacter, dan grup Kurthia. Hasil analisis kromatografi gas (GC-FID) menunjukkan bahwa enzim lipolitik yang dihasilkan bakteri-bakteri tersebut terdiri atas berbagai asam lemak. Beberapa isolat bakteri menghasilkan asam lemak esensial, seperti asam lemak: linoleat, linolenat, arakidonat, eikosapentanoat (EPA), dan dokosaheksanoat (DHA).

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The specific bacteria in forests and on oil palm plantations are lipolytic bacteria. Their enzymes have been applied in the agro-aquaculture, food, detergent, pharmaceutical, dairy, and biodiesel-biokerosene industries. This study describes the diversity of cultivable lipolytic bacteria from soil and aquatic sediment in a forest and on an oil palm plantation and their fatty acid products. Soil samples used in this research were obtained from topsoil in a lowland forest and on an oil palm plantation and from sediments in fresh water near these sites. The forest is located in Bukit Duabelas National Park, and the oil palm plantation is near the forest in Sarolangun District, Jambi Province, Indonesia. Twenty-two isolates of lypolitic bacteria were selected from 32 isolates grown in lipolytic selective medium. The 22 consisted of 11 isolates from topsoil and 11 from aquatic sediment from the forest and plantation area. These isolates were identified by 16S rRNA-sequence data analysis. Taxonomically, they belonged to five genera: Burkholderia, Cupriavidus, Serratia, Acinetobacter, and Kurthia. The maximum likelihood tree showed that they are phylogenetically distributed in three clusters. They were clustered into three groups: the Burkholderia-Cupriavidus group, the Serratia-Acinetobacter group, and the Kurthia group. Their lipolytic enzymes formed various fatty acids after analysis by gas chromatography-flame ionization detector (GC-FID). Some isolates formed essential fatty acids, such as linoleic, linolenic, arachidonic, eicosapentanoic acid (EPA), and docosahexanoic acid (DHA)."

"Proses hilirisasi bahan tambang menghasilkan emisi gas rumah kaca yang signifikan dan memberikan pengaruh besar pada pemanasan global. Proses produksi feronikel, misalnya, menghasilkan 45 kg CO2 untuk setiap 1 kg konten nikelnya. Amonia (NH3) telah muncul sebagai energi terbarukan yang dapat digunakan sebagai pengangkut dan pemasok hidrogen melalui penguraiannya menjadi hidrogen dan nitrogen. Keunggulan ini menjadikan amonia cocok sebagai bahan untuk memproduksi nikel yang ramah lingkungan karena dapat menggantikan bahan pereduksi berbasis fosil. Namun, studi tentang rute pirometalurgi untuk ekstraksi nikel laterit dengan NH3 sebagai reduktor masih sangat terbatas sehingga topik ini masih kurang dipahami. Penelitian ini bertujuan untuk mengeksplorasi proses reduksi nikel laterit menggunakan amonia sebagai reduktor serta menganalisis bagaimana variasi suhu memengaruhi struktur mikro dan fasa produk. Bijih nikel jenis laterit pada penelitian ini diperoleh dari daerah tambang di Indonesia. Penelitian mempertimbangkan variasi suhu antara 800-1300°C dengan variasi waktu tahan 30 menit dan 60 menit. Simulasi termodinamika menggunakan perangkat lunak HSC Chemistry 9.1.5® memprediksi bahwa reduksi bijih nikel laterit dengan amonia terjadi dalam dua tahap utama: dehidroksilasi dan reduksi. Secara termodinamika, pembentukan logam Fe dan Ni diprediksi terjadi pada suhu 900°C, namun secara eksperimental logam Fe dan Ni baru terbentuk pada suhu 1000°C. Hasil eksperimen menunjukkan bahwa suhu optimal adalah 1150°C, menghasilkan fasa Fe dan feronikel yang tinggi dengan derajat metalisasi optimal sebesar 94,78% sebagaimana dibuktikan melalui analisis XRD. Pengaruh waktu tahan memberikan peningkatan signifikan terhadap recovery Fe-Ni hingga 14,4% pada suhu 1100°C. Namun, pada suhu 1200°C, peningkatan rasio amonia tidak memberikan efek signifikan (hanya 2%) karena logam telah terperangkap dalam fasa slag yang stabil pada suhu tinggi. Analisis SEM menunjukkan kemampuan reduksi unik dari amonia yang tampak pada perubahan morfologi progresif dalam struktur mikro menghasilkan struktur porous dan tidak teratur disebabkan reduksi selektif oleh gas H2 hasil dekomposisi dari amonia.

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The downstream mining process generates significant greenhouse gas emissions and has a major influence on global warming. The ferronickel production process, for example, generates 45 kg of CO2 for every 1 kg of nickel content. Ammonia (NH3) has emerged as a renewable energy that can be used as a hydrogen transporter and supplier through its decomposition into hydrogen and nitrogen. These advantages make ammonia suitable as a material for producing environmentally friendly nickel because it can replace fossil-based reducing agents. However, studies on pyrometallurgical routes for laterite nickel extraction with NH3 as a reductant are still very limited so this topic is still poorly understood. This study aims to explore the reduction process of nickel laterite using ammonia as a reductant and analyze how temperature variation affects the microstructure and phase of the product. The laterite nickel ores in this study were obtained from mining areas in Indonesia. The study considers temperature variations between 800-1300°C with 30-minute and 60-minute holding times.  Thermodynamic simulations using HSC Chemistry 9.1.5® software predict that the reduction of lateritic nickel ore with ammonia occurs in two main stages: dehydroxylation and reduction. Thermodynamically, the formation of Fe and Ni metals is predicted to occur at 900°C, but experimentally Fe and Ni metals are only formed at 1000°C. The experimental results show that the optimum temperature is 1150°C, resulting in high Fe and ferronickel phases with an optimum degree of metallization of 94.78% as evidenced by XRD analysis. The effect of holding time provides a significant increase in Fe-Ni recovery up to 14.4% at 1100°C. However, at 1200°C, increasing the ammonia ratio did not have a significant effect (only 2%) because the metal had been trapped in the slag phase which is stable at high temperatures. SEM analysis shows the unique reducing ability of ammonia which is evident in the progressive morphological changes in the microstructure resulting in porous and irregular structures due to selective reduction by H2 gas from the decomposition of ammonia. "

"Saliva and Streptococcus mutans play role in biofilm formation. Saliva and S.mutans virulence are different between subjects with and without caries. Objective: The aim of this study was to evaluate the effects of autolog saliva on biofilm formation of S. mutans isolated from caries and caries-free subjects. Materials and Methods: Saliva and plaque samples are obtained from caries and caries-free subjects. Plaque samples were cultured on TYS20B for 3 days. Selected colonies were picked and cultured on TSB for 3 days. After colony counting, biofilm assay was conducted and inoculated for one day. The biofilm was tested using crystal violet binding assay and quantified by measuring the optical density at 655 nm wavelength. Result: The optical density of S. muttans biofilm isolated from subjects with caries were different from taste with no caries. Biofilm formation of S. muttans isolated from caries and caries-free subjects with and without the presence of autolog saliva were different. Conclusion: Autolog saliva influences S. mutans biofilm formation and there is a tendency that is higher than those from subjects with no caries. "

"Growth and yield of plants are increased when plants are provided with mixtures of nitrate and ammonium compared with either form alone. Therefore, the objective of this experiment was determine the optimum of nitrate and ammonium ratio caused an increased in growth and yield of green pak choy (Brassica chinensis L.) The experiment was designed in Randomized Completely Design with five treatments of nitrate ammonium ratios and arranged in four replication. The treatments of nitrate ammonium ratio were : 100/0; 75/25; 50/50; 25/75 and 0/100. The results showed that nitrogen fertilizer applied in mixture nitrate and ammonium gave different effects in leaf nitrate reductase activity, leaf nitrogen content, growth and yield of green pak choy. There was significant correlation between the leaf nitrate reductase activity and leaf nitrogen content. There was also significant correlation between the leaf nitrate reductase activity with growth and yield of green pak choy. Nitrate ammonium ratio at 75/25 and 50/50 have better affect on the leaf nitrate reductase activity, leaf nitrogen content, growth and yield of green pak choy"

"Zinc oxide (ZnO) nanorods have been considered as a potential semiconductor oxide material for the application of dye-sensitized solar cells (DSSC). Various experiments have been conducted to improve its nanostructural characteristics and functional properties in order to make it well suited for enhancing DSSC’ performance. Inspired by such studies, the ZnO nanorods array was grown on indium tin oxide (InSn2O3, ITO) substrate in the present work. For this purpose, a seed solution was prepared at low temperature (0oC) using zinc nitrate tetrahydrate and hexamethylenetetramine. The ZnO seed layers were deposited onto ITO glass using a spin-coating technique and further annealed at two different temperatures, 200 and 400 oC. The seeding was also varied between one, three and five layers, prior to the growing process using the chemical bath deposition method (CBD). The results showed that the annealing temperatures significantly influenced the ZnO nanorods’ growth. The optimal condition was achieved by using three seed layers annealed at 200oC, providing an average diameter of 157.58 nm, the biggest crystallite size (up to 59.63 nm), and a band-gap energy (Eg) of 3.27 eV. Based on the obtained properties, the growth of ZnO nanorods on ITO substrate in this work has the potential to be used for the application of dye-sensitized solar cells."

"Human dental pulp of exfoliated deciduous teeth contains the population of cells that exhibited mesenchymal stem cell (MSC) characters. Though, a cell amplification process is indeed required to secure and adequate cell number for such a potential employment. Several publications suggested the alteration of MSCs upon in vitro culture, for example, the decrease in proliferation and the loss of stem cell characters. Here, we investigated an influence of basic fibroblast growth factor (bFGF) on stem cells isolated from human exfoliated deciduous teeth (SHEDs) with respect to cell proliferation, colony forming unit efficiency and stem cell marker expression in both short- and long-term cultures. For short-term bFGF treatment, SHEDs were treated with bFGF for 48h. While, in long-term bFGF supplementation, SHEDs were maintained in culture and continuous passage upon confluence in medium supplemented witg bFGF. Cells at passage (P) 5 and 10 were employed for characterization. Our result showed that short-term bFGF treatment enhanced OCT4, REX1, and NANOG mRNA expression as well as colony forming unit ability. The FGFR inhibitor pretreatment was able to attenuate the influence of bFGF on pluripotent stem cell marker expression, confirming bFGF function. In addition, cells cultured in high passage number had decreased in cell proliferation, colony forming unit capacity, and pluripotent stem cell marker mRNA expression. However, bFGF supplementation in culture medium enhanced both pluripotent stem cell marker expression and colony forming unit capacity in later passage, though the effect was not robust. Together, these results indicate that high passage number may attenuate pluripotent properties of SHEDs and bFGF supplementation could be the beneficial approach to maintain SHEDs' stemness properties. "

"Telah dilakukan penapisan senyawa antimikroba terhadap 22 isolat Actinomycetes hasil isolasi dari sedimen pesisir Pulau Pramuka, Kepulauan Seribu, DKI Jakarta. Penapisan senyawa antimikroba dilakukan menggunakan metode plug dan hasil penapisan dinyatakan dalam indeks aktivitas IA . Hasil penapisan menunjukkan tidak terdapat aktivitas antimikroba terhadap Escherichia coli NBRC 3301. Namun terdapat 13 isolat yang mampu menghambat pertumbuhan Staphylococcus aureus NBRC 100910 IA 0,461-2,338, sebanyak 19 isolat mampu menghambat pertumbuhan Kocuria rhizophila NBRC 12708 IA 0,705-8,200, ada lima isolat dapat menghambat pertumbuhan Candida albicans UICC Y-29 IA 0,357-0,885, dan terdapat empat isolat yang mampu menghambat pertumbuhan Saccharomyces cerevisiae UICC Y-17 IA 0,357-1,348. Berdasarkan data penapisan, isolat SD 17 ditetapkan sebagai isolat terpilih karena mampu menghambat pertumbuhan dari bakteri Gram positif S. aureus dan K. rhizophila, serta yeast S. cerevisiae dan C. albicans yang diujikan. Penentuan waktu fermentasi yang optimal dari isolat SD17 untuk produksi senyawa antimikroba dilakukan dengan medium CSM Cross Streak Media dan PM4 Production Medium 4 pada hari ke-3, 6, 9, dan 12. Hasil uji aktivitas antimikroba dari filtrat medium pertumbuhan menunjukkan produksi senyawa antimikroba dari isolat SD 17 optimal pada hari ke-9 dengan menggunakan medium CSM. Uji aktivitas antimikroba hasil ekstraksi menggunakan pelarut etil asetat, pada konsentrasi 20 mg/mL, menunjukkan terdapat aktivitas antimikroba terhadap S. aureus IA 2,33, K. rhizhophila IA 4,71, S. cerevisiae IA 1,36 dan Candida albicans IA 0,22.

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Twenty two isolates of Actinomycetes have been screened for antimicrobial activity, all isolates were isolated from sediment in coastal Pramuka island, Kepulauan Seribu, Jakarta, Indonesia. Strains were screened for antimicrobial activity using plug method and determined by antimicrobial Activity Index AI. The result showed no inhibition activity was observed in the Escherichia coli NBRC 3301. However, there were 13 isolates inhibited Staphylococcus aureus NBRC 100910 0.461 mdash 2.338, 19 isolates inhibited Kocuria rhizophila NBRC 12708 0.705 mdash 8.200, 5 isolates inhibited Candida albicans 0.885 mdash 0.357, and 4 isolates inhibited Saccharomyces cerivisiae 0.357 mdash 1.348. Based on the results of antimicrobial test, SD17 is the most potential strain since it is able to inhibit all Gram positive and yeast tested. To acquire optimal period for antimicrobial fermentation from isolate SD 17, isolates were screened with two different fermentation medium Cross Streak Media CSM and Production Medium 4 PM4. Medium filtrates were tested at 3,6,9 and 12 days incubation. The result showed the optimal activity was observed at 9 days incubation using CSM. The result of antimicrobial test from medium extract with concentration 20 mg mL showed inhibition zone against S. aureus IA 2,33, K. rhizhophila IA 4,71, S. cerevisiae IA 1,36 and Candida albicans IA 0,22."