The design of unit cell metamaterial can tailor the permittivity and permeability. The negative refractive index was achieved while the negative real part of permittivity and negative real part of permeability simultaneously or εrμi+εiμr<0 conditions were satisfied, where εr,εi,μrandμiare real part of permittivity, imaginary part of permittivity, real part of permeability, and imaginary part of permeability, respectively. Currently, the metamaterial based on paper is a fascinating issue. Additional, paper is used as dielectric due to its eco‐friendly spacer. The unit cell design is the critical rule for achieving high figure of merit (FoM) of negative refractive index. This work aims to design the high FoM cylinder‐shaped negative refractive index metamaterial based on paper as the dielectric material. The cylinder‐shaped structure was simulated by CST microwave studio. The electromagnetic properties of the cylinder‐shaped structure were estimated from the scattering parameter (S‐parameter) result. The cylinder‐shaped structure yields high FoM of negative refractive index performance. The negative refractive index was generated at 3.4–3.91 GHz. The above condition or negative real permittivity and negative real permeability simultaneously were satisfied at 3.4–3.91 GHz. The high FoM was achieved at 3.5–3.91 GHz.
The tofu industry in Indonesia is growing rapidly along with the consumption needs. This amount affects the production of the tofu wastewater that will be discharged into the environment. The waste contains high levels of BOD, COD, and high protein organic substances. The discharged of the tofu wastewater without going through a good process of separation and treatment caused odor and pollution in the water and the soil environment. This study aims to examine the amount of production, a chemical characteristic, and bacterial potential (the genus of Pseudomonas and Aeromonas, proteolytic bacterial isolates, and potential phosphate solvent bacteria) which can be used as a reference for bioconversion of higher tofu wastewater. The method used in this study was water sampling, chemical characteristic testing (BOD, COD, total protein, and pH), the bacterial isolation of Pseudomonas and Aeromonas using GSP media, isolation of proteolytic bacteria using nutrient agar + Skim milk media and testing the solubilizing phosphate ability in pikovskaya media. The results showed the production of the tofu liquid waste reached 4000 liters/day with BOD, COD, total protein and pH content is 3210 mg/ L, 7102 mg/L, 20.74% and 5, respectively. The amount of indigenous bacteria in wastewater from Pseudomonas were 72 x 102 cfu/ml), Aeromonas were 18 x 102 cfu/ml), and total proteolytic bacteria were 23.7 x 105 cfu/ml). Proteolytic bacteria obtained in this research were 28 isolates with diverse proteolytic abilities. In addition, 17 of the 28 proteolytic bacteria isolates have the ability to soluble phosphate on pikovskaya medium. These results show that the production of the tofu liquid waste is quite high. Therefore, the chemical character and the presence of bacteria in it have the potential to be developed and can be used as a reference for bioconversion of waste before being discharged into the environment.Keywords: Aeromonas, proteolytic bacteria, tofu wastewater, phosphate solubilizing bacteria, Pseudomonas ABSTRAKIndustri tahu di Indonesia berkembang sangat pesat seiring dengan kebutuhan konsumsi masyarakat Indonesia. Jumlah ini berpengaruh terhadap produksi limbah cair tahu yang akan dibuang ke lingkungan. Limbah tersebut memiliki kandungan BOD, COD dan bahan organik berupa protein yang cukup tinggi. Limbah cair tahu jika dibuang lingkungan tanpa melalui proses pemisahan dan perlakuan yang baik dapat menimbulkan bau dan pencemaran di lingkungan air dan tanah. Penelitian ini bertujuan untuk mengkaji jumlah produksi, karakteristik kimia dan potensi biologi (bakteri genus Pseudomonas dan Aeromonas, isolat bakteri proteolitik dan bakteri pelarut fosfat potensial) yang nantinya dapat digunakan sebagai acuan biokonversi limbah cair tahu yang semakin tinggi. Metode yang digunakan pada penelitian ini adalah pengambilan sampel, pengujian karakteristik kimia (BOD, COD, total protein dan pH), isolasi bakteri genus Pseudomonas dan Aeromonas pada media GSP, isolasi bakteri proteolitik di media Nutrien agar + Skim milk dan pengujian kemampuan melarutkan fosfat pada media pikovskaya. Hasil menunjukkan bahwa limbah cair yang diproduksi setiap harinya mencapai 4000 liter/hari dengan kandungan BOD, COD, total protein dan pH berturut-turut sebesar 3210 mg/L, 7102 mg/L, 20.74 % dan 5. Jumlah bakteri indigeous dalam limbah cair tahu dari genus Pseudomonas adalah 72 x 102 cfu/ml, genus Aeromonas adalah 18 x 102 cfu/ml dan total bakteri proteolitik adalah 23.7 x 105 cfu/ml. Bakteri proteolitik yang diperoleh berjumlah 28 isolat dengan kemampuan proteolitik yang cukup beragam. Selain itu, 17 dari 28 isolat bakteri proteolitik tersebut memiliki kemampuan melarutkan fosfat pada media pikovskaya. Hasil ini menunjukkan bahwa produksi limbah cair tahu yang cukup tinggi, karakteristik kimia serta keberadaan bakteri didalamnya memiliki potensi untuk dikembangkan dan dapat dijadikan sebagai acuan untuk biokonversi limbah sebelum dibuang ke lingkungan.Kata kunci: Aeromonas, bakteri proteolitik, limbah cair tahu, bakteri pelarut fosfat, Pseudomonas
The house fly (Musca domestica) is a vector of disease-causing bacteria because of its habit of perching and feeding on various substrates of pathogenic bacteria. His role as a disease carrier contradicts the hadith narrated by Bukhari, which is "If a fly falls into your vessel, drown it and then remove it because one of its wings carries disease and the other is the cure". This hadith indicates the presence of antimicrobial compounds produced from the body of flies. Various research reports show that the truth of this hadith is that there are antimicrobial-producing bacterial symbionts on the wings of flies (left and right) that can kill pathogenic bacteria on one of the wings or both. Antimicrobial compounds are also produced naturally in the digestive tract of flies from the larval stage to adulthood as a response to the body's defense against the presence of pathogenic bacteria in their bodies. The antimicrobial compounds are lysozyme, defensin, cecropin, diptericin, and several antimicrobial peptide compounds. This compound can also be removed mechanically through pressure (the process of immersing the fly's body in water). This shows that the process of drowning aims to extract or release antimicrobial compounds from the digestive tract of flies to neutralize pathogenic bacteria that have mixed in the liquid in specific containers. This review aims to examine various reports related to antimicrobial substances produced in flies and their evidence in this hadith.Abstrak: Lalat rumah (Musca domestica) merupakan vektor pembawa bakteri penyebab penyakit karena kebiasaan hinggap dan makan pada berbagai substrat bakteri patogen. Perannya sebagai pembawa penyakit memiliki kontradiksi dengan hadist yang diriwayatkan oleh Bukhari yaitu “Jika seekor lalat jatuh ke bejana kamu, tenggelamkanlah kemudian singkirkan, karena salah satu sayapnya membawa penyakit dan sayap lainnya adalah obatnya”. Hadist ini mengindikasikan adanya senyawa antimikroba yang dihasilkan dari tubuh lalat. Berbagai laporan penelitian menunjukkan bahwa kebenaran hadist ini yaitu pada sayap lalat (kiri dan kanan) terdapat bakteri simbion penghasil antimikrob yang mampu membunuh bakteri patogen pada salah satu sayap atau keduanya. Senyawa antimikrob juga dihasilkan secara alami dalam pencernaan lalat sejak tahap larva hingga dewasa sebagai respon pertahanan tubuh terhadap keberadaan bakteri patogen ditubuhnya. Senyawa antimikrob tersebut berupa lisozim, defensin, cecrofin, diptericin dan beberapa senyawa peptida antimikrob. Senyawa ini juga dapat dikeluarkan secara mekanik melalui tekanan (proses penenggelaman tubuh lalat dalam air). Hal ini menunjukkan bahwa proses penenggelaman lalat kedalam air bertujuan untuk mengekstrak atau mengeluarkan senyawa antimikrob dari pencernaan lalat untuk menetralisir bakteri patogen yang telah bercampur dalam cairan di wadah tertentu. Review ini bertujuan untuk mengkaji berbagai laporan terkait senyawa antimikrob yang dihasilkan pada tubuh lalat dan pembuktiannya pada hadist tersebut.
Phosphorus (P) is a nutrient that is needed by plants. The availability of this element is greatly influenced by soil pH. As for ultisol soils classified as acid soils, most of the P in the soil is not available and is bound to Fe and Al. Pseudomonas, a phosphate solubilizing bacteria are soil microbes that can improve the availability of P in acid soils. This study aims to obtain Pseudomonas indigenous, a phosphate solubilizing bacteria from the acid soil formerly used by rubber plantations in the Institut Teknologi Sumatera. The study was conducted from April to June 2018 which included soil chemical analysis, isolation of the genus Pseudomonads on specific media, testing of phosphate solubility on solid Pikovskaya medium and simple pathogenicity test on potato tubers. The results showed that the sample soil was acidic with a pH of 4.09 with a P-availability of 0.78 ppm. From the soil samples, four potential isolates were obtained from the genus Pseudomonas, namely GSP 01, GSP 13, GSP 15 and GSP 06, with phosphate solubility indexes of 0.885, 0.639, 0.619 and 0.568, respectively. Isolates have the best phosphate solubilizing index on days 4 through 7. The four potential isolates are not pathogenic, so they can be used as isolates to improve the availability of soil nutrients, especially phosphorus needed by plants.Keywords: acid soil, phosphate solubilizing bacteria, phosphate availability, PseudomonasABSTRAKFosfor (P) merupakan unsur hara yang sangat dibutuhkan oleh tanaman. Ketersediaan unsur ini sangat dipengaruhi oleh pH tanah. Pada jenis tanah ultisol yang digolongkan sebagai tanah masam, sebagian besar dari P di tanah dalam bentuk yang tidak tersedia untuk diserap oleh tanaman dan berikatan dengan Fe dan Al. Pseudomonas pelarut fosfat merupakan mikroba tanah yang dapat memperbaiki ketersediaan P pada tanah masam. Penelitian ini bertujuan untuk mendapatkan Pseudomonas pelarut fosfat indigenous dari tanah masam bekas lahan perkebunan karet di kawasan Institut Teknologi Sumatera. Penelitian dilaksanakan pada bulan April sampai Juni 2018 yang meliputi analisis kimia tanah, isolasi bakteri genus Pseudomonads pada medium spesifik, uji kemampuan pelarutan fosfat pada medium Pikovskaya padat serta uji patogenitas sederhana pada umbi kentang. Hasil penelitian menunjukkan bahwa tanah sampel bersifat masam dengan pH 4,09 dengan P tersedia sebesar 0,78 ppm. Dari sampel tanah diperoleh empat isolat potensial yang diperoleh merupakan genus Pseudomonas yaitu GSP 01, GSP 13, GSP 15 dan GSP 06, dengan indeks pelarutan fosfat berturut-turut sebesar 0,885, 0,639, 0,619 dan 0,568. Isolat memiliki indeks pelarutan fosfat terbaik pada hari ke-4 hingga hari ke-7. Keempat isolat potensial tidak bersifat patogen sehingga mampu dijadikan sebagai isolat yang dapat digunakan untuk memperbaiki ketersediaan unsur hara tanah terutama fosfor yang dibutuhkan oleh tanaman.Kata kunci: bakteri pelarut fosfat, fosfat tersedia, Pseudomonas, tanah masam
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