Interpretasi Lingkungan Pengendapan Formasi Talang Akar Berdasarkan Data Cutting dan Wireline Log pada Lapangan X Cekungan Sumatera Selatan

A sedimentary environment is a part of earth\u27s surface which is physically, chemically and biologically distinct from adjacent terrains (Selley, 1988). The study of the depositional environment is one goal of many studiesconducted for academic purpose and economically purpose in oil and gas exploration. The study of the depositionalenvironment requires a fairly comprehensive analysis as to sequencestratigraphy facies analysis to obtain detailedinterpretations or conclusions. The purpose of this study is to analyze cutting and wireline logs to determinelithology, facies and sedimentation history of theTalang Akar formation field X in South Sumatra basin. The method used to analyze the formation of depositional environment of Talang Akar field X in SouthSumatra basin is the cutting description in order to know the composition of the constituent formations. While theanalysis conducted is cutting analysis to get lithofacies interpretation, second is well log analysis method to getsubsurface data such as physical rock properties then electrofacies analysis based on gamma ray log pattern andthird is stratigraphy sequence analysis method so sea level changed can be known. Stratigraphy sequenceinterpretation did base on facies and gamma ray log pattern changed. Pratama-1 well lithology consists of shale, siltstone, very fine sandstone until medium sandstone andlimestones. While the well lithology Pratama-2 is composed of shale, very fine until medium sandstone and siltstone.Facies found in wells Pratama-1 consists of distributary channel fill, prodelta, distal bar, distributary mouth bar,and marsh. Facies in wells Pratama-2 is a mud flat and mixed flat. In Pratama-1 wells are 2 sets sequence that bounded by 2 sequence boundary, with a stratigraphic unit LST, TST and HST with progradation andretrogradation stacking patterns. While the Pratama-2 wells contained one stratigraphic unit sequence that is onlyTST in progradation and agradation stacking patterns. Based on this analysis the Talang Akar formation field X inSouth Sumatra basin has a transitional depositional environment

TiO₂ Nanoparticle Exposure and Illumination during Zebrafish Development: Mortality at Parts per Billion Concentrations

Photoactivation of titanium dioxide nanoparticles (TiO₂NPs) can produce reactive oxygen species (ROS). Over time, this has the potential to produce cumulative cellular damage. To test this, we exposed zebrafish (<i>Danio rerio</i>) to two commercial TiO₂NP preparations at concentrations ranging from 0.01 to 10 000 ng/mL over a 23 day period spanning embryogenesis, larval development, and juvenile metamorphosis. Fish were illuminated with a lamp that mimics solar irradiation. TiO₂NP exposure produced significant mortality at 1 ng/mL. Toxicity included stunted growth, delayed metamorphosis, malformations, organ pathology, and DNA damage. TiO₂NPs were found in the gills and gut and elsewhere. The two preparations differed in nominal particle diameter (12.1 ± 3.7 and 23.3 ± 9.8 nm) but produced aggregates in the 1 μm range. Both were taken up in a dose-dependent manner. Illuminated particles produced a time- and dose-dependent increase in 8-hydroxy-2′-deoxyguanosine DNA adducts consistent with cumulative ROS damage. Zebrafish take up TiO₂NPs from the aqueous environment even at low ng/mL concentrations, and these particles when illuminated in the violet-near UV range produce cumulative toxicity