Growth, mortality and recruitment of commercially important fishes and penaeid shrimps in Indonesian waters

Population dynamics, Stock assessment, Commercial species, Shrimp fisheries, Arafura Sea, Indonesia, Penaeus merguiensis

Easy Handling Preparation of Cubic Sulfur in Aqueous Extract of Sapindus rarak rinds

The aqueous extract of Sapindus rarak (S. rarak) was produced by heating its rinds in demineralized water at 80 °C. The main experiment was conducted at room temperature by mixing a solution of sodium thiosulfate with the extract obtained previously. After adding dilute hydrochloric acid (10%), fine granules gradually formed in the solution and precipitated when the reaction was stopped and allowed to stand for 24 h. The analysis results showed the consistency of the X-ray diffraction (XRD) peak of the obtained material with sulfur standards. When looked at the surface using scanning electron microscopy (SEM), sulfur was found to be cube-shaped. The formation of cuboidal elemental sulfur possibly occurs due to the covering of thiosulfate ions and elemental sulfur during and after the reaction. Organic compounds were found covering sulfur through elemental and functional group analyses using energy-dispersive X-ray (EDX) and Fourier-transform infrared (FTIR) spectroscopy, respectivel

Aktivitas Antibakteri Secara In-Vitro Ekstrak Metanol Excoecaria cochinchinensis Lour dan Kombinasinya dengan Obat Komersial

The purpose of this study was to look into the antibacterial activity of methanolic extract of Excoecaria cochinchinensis as well as the effect of its combination with antibiotics on the growth of Klebsiella pneumoniae, Enterobacter aerogenes, and Staphylococcus epidermidis. The antibacterial activity test was carried out using the well diffusion method, and the combined effect of the extract and antibiotics was observed using the paper strip diffusion method. At various concentrations (25, 50, 75, 100, 150, 200, and 250 mg/mL), the extract significantly inhibited the growth of K. pneumoniae, E. aerogenes, and S. epidermidis. The inhibitory zone's diameter increased proportionally with the extract concentration. The growth of K. pneumoniae and S. epidermidis was then classified as extremely sensitive (+++) to the addition of the extract at 200 and 250 mg/mL concentrations, meanwhile, E. aerogenes’s with 250 mg/mL of the extract. Secondary metabolites such as oleanolic acid, arjunolic acid, scopoletin, kaempferol, quercetin, diterpenoid compounds, tannins, and other phenolics have been reported from E. cochinchinensis leaves and are thought to be responsible for its antimicrobial activity. The effect of the extract’s combination with antibiotics was insignificant compared to their individual activity, thereby classifying them as indifferent.Tujuan dari penelitian ini adalah untuk menyelidiki aktivitas antibakteri dari ekstrak metanol Excoecaria cochinchinensis serta pengaruh kombinasinya dengan antibiotik terhadap pertumbuhan Klebsiella pneumoniae, Enterobacter aerogenes, dan Staphylococcus epidermidis. Uji aktivitas antibakteri dilakukan dengan metode difusi sumuran, dan efek gabungan dari ekstrak dan antibiotik diamati dengan menggunakan metode difusi kertas. Pada berbagai konsentrasi (25, 50, 75, 100, 150, 200, dan 250 mg/mL), ekstrak secara signifikan menghambat pertumbuhan K. pneumoniae, E. aerogenes, dan S. epidermidis. Selain itu, peningkatan diameter zona hambat berbanding lurus dengan peningkatan konsentrasi ekstrak. Pertumbuhan K. pneumoniae dan S. epidermidis kemudian diklasifikasikan sebagai sangat sangat sensitif (+++) terhadap penambahan ekstrak pada konsentrasi 200 dan 250 mg/mL. Sementara itu, pertumbuhan E. aerogenes diklasifikasikan sebagai sangat sangat sensitif (+++) ketika diberikan 250 mg/mL ekstrak. Metabolit sekunder seperti asam oleanolik, asam arjunolik, skopoletin, kaempferol, kuersetin, senyawa diterpenoid, tanin, dan fenolat lainnya telah dilaporkan dari daun E. cochinchinensis dan diduga bertanggung jawab atas aktivitas antimikrobanya. Efek kombinasi ekstrak dengan antibiotik tidak terjadi peningkatan signifikan jika dibandingkan dengan aktivitas secara tunggal, sehingga diklasifikasikan sebagai efek indifferent

EKSTRAK BUNGA TAPAK KUDA (Ipomoea pescaprae L. Sweet) SEBAGAI MEDIUM SINTESIS NANOPARTIKEL EMAS

Pada penelitian ini, nanopartikel emas disiapkan melalui pendekatan green synthesis menggunakan ekstrak air bunga tapak kuda (Ipomoea pescaprae L. Sweet). Nanopartikel emas yang dihasilkan dianalisis menggunakan spektrofotometer UV-Vis, Mikroskop Leica, Particle Size Analyzer (PSA), Spektrofotometer Fourier Transform Infra-Red (FTIR) dan X-ray Difractometer (XRD). Hasil pengukuran  PSA menunjukkan ukuran partikel terbaik, diperoleh dengan menggunakan perbandingan volume 1 mL  larutan HAuCl4 dengan 9 mL ekstrak yang menghasilkan partikel dengan ukuran rata-rata 16,3 nm. Hasil penampakan dengan mikroskop cahaya, memperlihatkan partikel berbentuk bulat. Pergeseran bilangan gelombang pada spektrum infra-merah menunjukkan adanya interaksi antara metabolit sekunder dari ekstrak dengan material emas. Analisis XRD menunjukkan bahwa nanopartikel emas telah dapat dihasilkan dari kondisi reaksi ini

Fabrication of Silver-Silica Composite using the Carbo-thermal Degradation of Oil Palm Leaves for the Reduction of p-nitrophenol

Oil palm leaves are natural sources of bio-silica. In situ carbothermal degradation was conducted at 600°C using silver nitrate as a metallic silver (Ag) precursor and oil palm leaves as a silica (SiO2) source. X-ray diffraction of the solid product (Ag@OPLA600) revealed the presence of Ag and SiO2 from the oil palm leaves. Fourier transform infrared spectroscopy showed an absorbance consistent with the presence of SiO2. Scanning electron microscopy revealed a solid surface with cavities. Ag@OPLA600 was used as a heterogeneous mediator to reduce p-nitrophenol to p-aminophenol within 15 minutes. This work provides a new approach for the utilization of sustainable natural resources as a metal Ag supporting material to produce a mediator for the conversion of p-nitrophenol to p-aminophenol in a simple manner

Seismic damage estimation of in-plane regular steel/concrete composite moment resisting frames

© 2016 Elsevier Ltd. Simple empirical expressions to estimate maximum seismic damage on the basis of four well known damage indices for planar regular steel/concrete composite moment resisting frames having steel I beams and concrete filled steel tube (CFT) columns are presented. These expressions are based on the results of an extensive parametric study concerning the inelastic response of a large number of frames to a large number of ordinary far-field type ground motions. Thousands of nonlinear dynamic analyses are performed by scaling the seismic records to different intensities in order to drive the structures to different levels of inelastic deformation. The statistical analysis of the created response databank indicates that the number of stories, beam strength ratio, material strength and ground motion characteristics strongly influence structural damage. Nonlinear regression analysis is employed in order to derive simple formulae, which reflect the influence of the aforementioned parameters and offer a direct estimation of the damage indices used in this study. More specifically, given the characteristics of the structure and the ground motion, one can calculate the maximum damage observed in column bases and beams. Finally, three examples serve to illustrate the use of the proposed expressions and demonstrate their accuracy and efficiency

Aquatic ecosystems in Byers Peninsula, Livingston Island. An Antarctic Noah’s Ark in a changing world

第6回極域科学シンポジウム[OB] 極域生物圏11月17日（火）　統計数理研究所 セミナー室1（D305