Combined LRRK2 mutation, aging and chronic low dose oral rotenone as a model of Parkinson’s disease

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Comparison of Temperate and Topical Saltwater Species' acute sensitivities distributions to chemicals: implication for deriving safe extrapolation factor

Poster presentation: P-61Human ImpactsDue to a lack of saltwater toxicity data in tropical regions, toxicity data generated from temperate or cold water species endemic to North America and Europe are often adopted to derive water quality guidelines (WQG) for protecting tropical marine ecosystems. Given the differences in species composition and environmental attributes between tropical and temperate saltwater ecosystems, there are conceivable uncertainties in such ‘temperate-to-tropic’ extrapolations. This ...postprin

Social Media and Depressive Symptoms in Childhood and Adolescence: A Systematic Review

Concerns are increasingly raised in academic and lay literature about the impact of the internet on young people’s well-being. This systematic review examined empirical research on the relationship between social media use and depressive symptoms in the child and adolescent population. A systematic search of Medline, PsycInfo and Embase databases yielded eleven eligible studies. Relevant results were extracted from each study, with a total sample of 12,646. Analysis revealed a small but statistically significant correlation between social media use and depressive symptoms in young people. However, studies varied widely in methods, sample size and results, making the clinical significance of these findings nuanced. Over half of the studies were cross-sectional, while those of longitudinal design were of limited duration. This review justifies further investigation of this phenomenon, with a need for consensus on variables and measurement

Metal nitrido and imido photo-oxidants. Photophysics and photochemistry of nitrido and imido complexes of osmium(VI) and X-ray crystal structure of [Ph4As]2[OsVI(CN)5N]

Nitrido- and imido-osmium(VI) complexes with cyanides as ligands have been synthesised and found to display intense photoluminescence in fluid solutions at room temperature; the X-ray structure of [Ph4As]2[Os VI(CN)5N] has been determined with a measured Os≡N distance of 1.647(7) Å.link_to_subscribed_fulltex

Application of solid phase microextraction in the determination of paralytic shellfish poisoning toxins

A SPME-HPLC-post-column fluorescent derivatization method for the direct determination of saxitoxin (STX), the most potent paralytic shellfish poisoning (PSP) toxin, in water has been developed. Commercially available SPME devices with 50 μm Carbowax templated resin (CW/TPR) coating was found to be able to pre-concentrate STX from aqueous media. A special pre-conditioning treatment of soaking the SPME coating in 0.1 M NaOH solution significantly improved the extraction efficiency. The optimal pH for the SPME process is 8.1 and the equilibration time is 40 min. The partition coefficient, K, of the distribution of STX between the SPME coating and the aqueous media was measured to be 2.99 ± 0.04 × 103. Extracted toxin on the SPME stationary phase was difficult to be desorbed by the HPLC mobile phase under dynamic desorption mode. A static ion-pairing desorption technique using a desorption solvent mixture of 20 mM sodium 1-heptanesulfonate in 30% aqueous acetonitrile acidified with 50 mM sulfuric acid was developed to overcome this problem. The method detection limit and repeatability achieved by this SPME-HPLC method were 0.11 ng ml-1 and 3.7%, respectively, with a sample volume of just 5 ml of water. This analytical method is adequate for the monitoring of the PSP toxin in fresh/drinking waters. However, serious interference was observed when this technique was applied to saline water samples. This is probably due to competition of sodium ions with the cationic STX for absorption into the SPME stationary phase. © The Royal Society of Chemistry 2005.link_to_subscribed_fulltex

Acute and chronic toxicities of Irgarol alone and in combination with copper to the marine copepod Tigriopus japonicus

Irgarol 1051 has been widely used as a booster biocide in combination with copper (Cu) in antifouling paints. The combined toxicity of Irgarol with Cu on marine organisms, however, has not been fully investigated. This study investigated the acute and chronic toxicities of binary mixtures of Irgarol and CuSO 4 to the marine copepod Tigriopus japonicus. The acute combined toxicity of Irgarol and Cu was simple additive as revealed by two response surface models and their contours. However, based on chronic full life-cycle tests, when Irgarol was combined with Cu at an environmentally realistic concentration (10 μg L -1), a slightly synergistic effect was observed at a high Irgarol concentration (940 μg L -1), as shown by a significant increase in larval mortality. As Cu contamination is widespread in coastal environments, our results entail the importance of considering the combined toxic effect of the booster biocide and Cu for setting ecologically realistic water quality criteria. © 2012 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex

A whole life cycle assessment on effects of waterborne PBDEs on gene expression profile along the brain-pituitary-gonad axis and in the liver of zebrafish

Polybrominated diphenyl ethers (PBDEs) are now found ubiquitously in the aquatic environment and biota, and there is a growing concern that PBDEs may disrupt endocrine systems, leading to reproductive impairments of aquatic animals. In our study, zebrafish (Danio rerio) were exposed to the 5. ng/L, 1. μg/L and 50. μg/L of DE-71 for the duration of the whole life cycle (120. days, from eggs to adults). The expression of selected genes along the brain-pituitary-gonadal (BPG) axis and liver, and the levels of plasma sex hormones were examined.In male fish, up-regulation of GnRH in brain, FSHβ and LHβ in pituitary, FSH-receptor, LH-receptor, and CYP19a in testis was clearly evident, while down-regulation of CYP11a and 3β-HSD was found in testis. In female fish, a 2.4-fold up-regulation of 3β-HSD was found in ovary upon exposure to 50. μg/L of DE-71. GnRH in brain, FSHβ and LHβ in pituitary were also up-regulated, while ERβ, TH and TPH in brain and GnRH-receptor in pituitary were significantly down-regulated. Hepatic ERα, AR and VTG in males were all down-regulated, while hepatic ERα and AR in female were up-regulated.Serum estradiol (E 2) was reduced in both male and female upon exposure to DE-71, while significant increases in serum testosterone (T) and 11-keto-testosterone (11-KT) were only found in male but not female fish. The ratio of T/E 2 as well as the ratio of 11-KT/E 2 in male fish increased in a dose-dependent manner upon exposure to DE-71. Our overall results showed that whole life exposure of DE-71 altered the expression of regulatory genes and receptors at all three levels of the BPG axis in zebrafish, and the responses are sex dependent. The observed disruption of GnRH and GtHs can be further related to the subsequent disruption in both levels and balance sex steroid hormones. © 2011 Elsevier Ltd.link_to_subscribed_fulltex

Behavior of trace metals in the sediment pore waters of intertidal mudflats of a tropical wetland

Vertical profiles of dissolved Cd, Cr, Cu, Pb, Zn, Fe, and Mn in the sediment pore waters of the intertidal mudflats of the Mai Po and Inner Deep Bay Ramsar Sire of Hong Kong, People's Republic of China, were measured using the polyacrylamide gel diffusive equilibration thin film (DET) technique. The ranges of concentrations of dissolved Cd, Cr, Cu, Pb, Zn, Fe, and Mn in the pore water of the top 0 to 20 cm of sediment were 2.2 to 10.0 nM, 346.0 to 950.0 nM 243.8 to 454.8 nM, 23.2 to 51.2 mM, 39.8 to 249.5 mu M, and 13.4 to 20.7 mu M, respectively. Enrichment of these trace metals was observed in the upper 0- to 7-cm layer. Profiles of conditional distribution coefficient, log(K-D), of the trace metals and results of multiple regression analysis have revealed that reduction of Mn (hydrous) oxides was the major remobilization mechanism for Cd, Cr, Cu, Pb, and Zn in the mudflats. Benthic diffusive fluxes of these trace metals from the mudflats were also estimated on the basis of the concentration gradients of trace metals between surface sediments and the overlying water column. The magnitude of the estimated diffusive fluxes followed the order Zn > Cr > Cu > Pb > Cd