Atrazine is an herbicide applied to agricultural crops and is indicated to be an endocrine disruptor. Atrazine is frequently found to contaminate potable water supplies above the maximum contaminant level of 3 µg/L as defined by the U. S. Environmental Protection Agency. The developmental origin of adult disease hypothesis suggests that toxicant exposure during development can increase the risk of certain diseases during adulthood. However, the molecular mechanisms underlying disease progression are still unknown. In this study, zebrafish embryos were exposed to 0, 0.3, 3, or 30 µg/L atrazine throughout embryogenesis. Larvae were then allowed to mature under normal laboratory conditions with no further chemical treatment until 7 days post fertilization (dpf) or adulthood and neurotransmitter analysis completed. No significant alterations in neurotransmitter levels was observed at 7 dpf or in adult males, but a significant decrease in 5-Hydroxyindoleacetic acid (5-HIAA) and serotonin turnover was seen in adult female brain tissue. Transcriptomic analysis was completed on adult female brain tissue to identify molecular pathways underlying the observed neurological alterations. Altered expression of 1853, 84, and 419 genes in the females exposed to 0.3, 3, or 30 µg/L atrazine during embryogenesis were identified, respectively. There was a high level of overlap between the biological processes and molecular pathways in which the altered genes were associated. Moreover, a subset of genes was down regulated throughout the serotonergic pathway. These results provide support of the developmental origins of neurological alterations observed in adult female zebrafish exposed to atrazine during embryogenesis.
A novel ordered porous Bi2O3 inverse opal structure (IOS) was prepared using a polystyrene (PS) photonic crystal as the template for the first time. Nitrogen-doped carbon dots (N-CDs) were chosen to sensitize the as-prepared Bi2O3 IOS for improving photoelectrochemical performance and photocatalytic activity. The photocurrent density of the fabricated N-CDs/Bi2O3 IOS with favorable visible light absorption properties can achieve 0.75 mA cm(-2), which significantly enhanced performance two-, seven-, and thirty-fold compared with that of the CDs/Bi2O3 IOS, Bi2O3 IOS, and Bi2O3 nanoparticles (NPs), respectively. The N-CDs/Bi2O3 IOS also has increased photocatalytic activity for the decolorization of Rhodamine B (RhB), 4 times higher than Bi2O3 NPs. The above performance enhancement of N-CDs/Bi2O3 IOS is caused by the synergistic effect of N-CDs sensitization and the highly ordered IOS, which make it a promising material to be used in clean energy, solar cells, potential applications in water purification and so on.
Athabasca asphaltene was ultrasonically processed under a variety of conditions. Five discrete ultrasonic frequencies and four saturating gases were explored. The kinetics of the reduction in the number average molecular weight (NAMW) were determined by vapor pressure osmometry measurements and UV/visible spectrophotometric measurements. The NAMWs decreased significantly after short treatment times (from ∼1200 to ∼470 g/mol in 15 min). The observed reduction in the NAMWs of asphaltene was greatest at 358 kHz. At a frequency of 205 kHz, the observed reduction in NAMW was fastest with a mixture of Ar/H 2 (50%/50% v/v), whereas saturating with hydrogen, air, and oxygen gases exhibited minimal effect on the kinetics. Visible light absorption spectra of asphaltene samples demonstrate that heptane soluble fractions increase by >50% after sonochemical treatment as an upgrading process.
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