Hepatic CYP1A levels and EROD activity in English sole: biomonitoring of marine contaminants in Vancouver Harbour

To assess chemical contaminant stress in the marine environment, ethoxyresorufin-O-deethylase (EROD) activity and cytochrome P450 1A (CYP1A) expression were measured in 88 English Sole (Pleuronectes vetulus) collected during May and June 1999 from four sites in Vancouver Harbour and at an expected reference site outside the harbour. Hepatic microsomes were prepared from the fish and analyzed for total CYP content, EROD activity, and CYP1A protein levels. Hepatic EROD activity and CYP1A protein levels were elevated in fish from two sites in the inner harbour. A comparison with sediment chemistry data showed that fish with increased EROD activity and CYP1A levels came from sites containing relatively high levels of polycyclic aromatic hydrocarbons and polychlorinated biphenyls. Unexpectedly high levels of EROD activity and CYP1A protein were also found in fish from a reference site near Gibsons, in Howe Sound. The elevated EROD activity and CYP1A expression in fish from this site cannot be explained by the chemical analysis data collected.     

Interactive effects of UV, benzo[alpha] pyrene, and cadmium on DNA damage and repair in embryos of the grass shrimp Paleomonetes pugio

We examined the link between DNA strand breaks and hatching rates in grass shrimp, (Paleomonetes pugio), embryos exposed to 0.2 microM benzo[alpha] pyrene (BP), 5 microM cadmium (Cd) and 330 kJ/m(2) UV light, either alone or together. After exposure, embryos were transferred to clean seawater with or without 5 microM Cd. Hatching rates and DNA strand breaks (Comet Assay) were determined. DNA lesions caused by exposure to BP, UV light, or BP/cadmium were rapidly repaired and were not associated with any effects on hatching. Exposure to Cd after exposure to BP or UV did not affect embryological development or DNA repair. Exposure to BP/UV resulted in a high level of DNA lesions which were slowly repaired. Exposure to cadmium following BP/UV exposure inhibited hatching and DNA repair. Adducts formed during exposure to BP/UV exposure may be difficult to excise or may saturate the nucleotide excision repair system.     

“多维动态GIS空间数据处理关键技术”通过验收

由国家基础地理信息中心、清华大学和武汉大学合作承担 ,陈军教授主持完成的国家自然科学基金重点项目“多维动态GIS空间数据处理关键技术”研究 ,近日通过国家自然科学基金委员会信息科学部组织的验收。该项目包括多维动态GIS的基本概念 ,时空数据模型与建模方法 ,3D空间数据模型与建模方法 ,动态空间关系生成与操作 ,空间关系的集成化表示与推理 ,球面动态数据建模、生成、索引 ,基于Web的空间数据处理 ,大规模地表模型的实时动态显示 ,三维城市景观可视化技术以及三维数据获取等 ,并在多个方面有创新 ,这一成果为我国构建新一代数字…     

Detection of Extended Thermal Infrared Emission around the Vega-like Source HD 141569

We report the detection of extended IR emission at 10.8 and 18.2 μm around the Vega-like source HD 141569. Mid-IR imaging with OSCIR on Keck II shows emission from dust extending out to 100 AU from the B9.5 Ve star. Our modeling of the dust places an upper limit of approximately 2 μm on the diameter of the mid-IR-emitting particles if they are Mie spheres of astronomical silicates. Comparison of our mid-IR images to the near-IR (1.1 μm) NICMOS images of HD 141569 (Weinberger et al. 1999) shows that the mid-IR emission originates at smaller distances from the star than the scattered near-IR light, as also previously observed for the archetype Vega-like source beta Pictoris.     

潜孔锤钻进岩石的可钻性

岩石可钻性可通过分析它的矿物成分、抗压强度、晶粒尺寸和结构来获得。在不同钻进设备条件下,不同的岩石材料特征有不同的结果。硬岩破碎通常需要大的冲击能量以及扭矩;研磨性岩石导致钻头钢体、接头和活塞套磨耗较大和使用寿命减少。     

Biomarker responses in pelagic and benthic fish over 1 year following the Hebei Spirit oil spill (Taean, Korea)

After the Hebei Spirit oil spill incident (7th December, 2007) in the west coast of Korea, contamination of biliary PAH metabolite and hepatic biomarkers in a pelagic and a benthic fish was monitored for 1 year. Concentrations of 16 PAHs and alkylated PAHs in fish muscle were highest (22.0 ng/g d.w. for 16 PAHs and 284 ng/g d.w. for alkylated PAHs) at 5 days after the spill and then decreased rapidly to background levels at 11 months after the spill. Fish from the oiled site had elevated biliary PAH metabolite concentrations immediately after the spill; these declined steadily in both species, but were still above reference site concentrations 2 months after the spill. Oiled-site fish showed hepatic CYP 1A induction whose trend closely followed those of biliary PAH metabolite concentrations, implying continuous exposure to PAHs. Brain acetylcholinesterase activity was not related to oil exposure.     

Linear Free Energy Relationships for Metal-Ligand Complexation: Bidentate Binding to Negatively-Charged Oxygen Donor Atoms

Stability constants for metal complexation to bidentate ligands containing negatively-charged oxygen donor atoms can be estimated from the following linear free energy relationship (LFER): log K_ML = χ_OO(α_O log K_HL,1 + α_O log K_HL,2) where K_ML is the metal-ligand stability constant for a 1:1 complex, K_HL,1 and K_HL,2 are the proton-ligand stability constants (the ligand pK_a values), and α_O is the Irving-Rossotti slope. The parameter χ_OO is metal specific and has slightly different values for five and six membered chelate rings. LFERs are presented for 21 different metal ions and are accurate to within approximately 0.30 log units in predictions of log K_ML values. Ligands selected for use in LFER development include dicarboxylic acids, carboxyphenols, and ortho-diphenols. For ortho-hydroxybenzaldehydes, α-hydroxycarboxylic acids, and α-ketocarboxylic acids, a modification of the LFER where log K_HL,2 is set equal to zero is required. The chemical interpretation of χ_OO is that it accounts for the extra stability afforded to metal complexes by the chelate effect. Cu-NOM binding constants calculated from the bidentate LFERs are similar in magnitude to those used in WHAM 6. This LFER can be used to make log K_ML predictions for small organic molecules. Since natural organic matter (NOM) contains many of the same functional groups (i.e. carboxylic acids, phenols, alcohols), the LFER log K_ML predictions shed light on the range of appropriate values for use in modeling metal partitioning in natural systems.     

Thermal treatment as a method to control transfers of invasive biofouling species via vessel sea chests

This study examined the efficacy of heated seawater for the treatment and remediation of fouled vessel sea chest habitats. In laboratory trials, three temperature regimes (37.5°C for 60 min, 40°C for 30min and 42.5°C for 20 min) were tested on a range of temperate taxa commonly found in sea chests. Field validation trials further assessed the efficacy of heat treatment within a replica sea chest environment. During laboratory trials, 100% mortality was achieved across all three treatments for the majority of taxa; the exceptions being the barnacle Elminius modestus and the oyster Crassostrea gigas. Temperature tolerance limits observed in the laboratory were successfully replicated under simulated sea chest conditions; however, a failure to achieve even heat distribution was an obstacle to achieving uniform mortality. This study provides guidance on the temperature/exposure parameters required for vessels plying temperate latitudes, and demonstrates that heated seawater has potential for controlling biofouling in vessel sea chests.