吸烟与非吸烟肺癌患者中P53基因突变的检测

P53基因定位于人类第17号染色体的短臂,野生型P53基因是肿瘤抑制基因。这一基因正成为研究人类肿瘤DNA的主要目标。作者运用聚合酶链反应－单链构象多态性技术（PCR－SSCP）,研究了45例石蜡包埋的肺癌组织标本中肿瘤抑制基因P53基因突变,结果发现在P53基因的第5～8外显子中共检测到19例P53基因突变的样本,检出率为42.2％,并且发现吸烟的肺癌患者中P53基因突变的检出频率明显高于非吸烟的肺癌患者。     

Biotransformation of 17α-methyltestosterone in sediment under different electron acceptor conditions

17α-Methyltestosterone (MT), an anabolic androgenic steroid, is used widely in inducing an all male population in aquaculture farming of fish, such as Nile tilapia (Oreochromis niloticus). Current understanding of the occurrence and fate of MT in the sediments and the surrounding areas of the aquaculture ponds are very limited. Bioassay tests showed that MT was biotransformed under aerobic and sulfate-reducing conditions with a half-life of 3.8 d and 5.3 d, respectively, with complete disappearance of androgenic activity. However, under methanogenic condition, MT was found to biotransform but the androgenic activity continued to persist even after 45 d of incubation. In contrast, MT was found to transform slowly under iron(III)-reducing condition and was hardly transformed under nitrate-reducing condition. A possible reason for the lack of transformation of MT under nitrate-reducing condition is the presence of the methyl group at the C-17 position. The results of this study suggest that MT and its degradation products with androgenic activity may potentially accumulate in the sediments of fish farming ponds under iron(III)-reducing, nitrate-reducing and methanogenic conditions.     

Mineralization of PAHs in coal-tar impacted aquifer sediments and associated microbial community structure investigated with FISH

The microbial community structure and mineralization of polycyclic aromatic hydrocarbons (PAHs) in a coal-tar contaminated aquifer were investigated spatially using fluorescence in situ hybridization (FISH) and in laboratory-scale incubations of the aquifer sediments. DAPI-detected microbial populations in the contaminated sediments were three orders of magnitude greater than nearby uncontaminated sediments, suggesting growth on coal-tar constituents in situ. Actinobacteria, beta- and gamma-Proteobacteria, and Flavobacteria dominated the in situ aerobic (>1 mg l(-1) dissolved oxygen) microbial community, whereas sulfate-reducing bacteria comprised 37% of the microbial community in the sulfidogenic region of the aquifer. Rapid mineralization of naphthalene and phenanthrene were observed in aerobic laboratory microcosms and resulted in significant enrichment of beta- and gamma-Proteobacteria potentially explaining their elevated presence in situ. Firmicutes, Flavobacteria, alpha-Proteobacteria, and Actinobacteria were also enriched in the mineralization assays, but to a lesser degree. Nitrate- and sulfate-limited mineralization of naphthalene in laboratory microcosms occurred to a small degree in aquifer sediments from locations where groundwater chemistry indicated nitrate- and sulfate-reduction, respectively. Some iron-limited mineralization of naphthalene and phenanthrene was also observed in sediments originating near groundwater measurements of elevated ferrous iron. The results of this study suggest that FISH may be a useful tool for providing a much needed link between laboratory microcosms and groundwater measurements made in situ necessary to better demonstrate the potential for natural attenuation at complex PAH contaminated sites.     

Modification of a full-scale sequencing batch reactor operational mode for biological nutrient removal.

Two biological nutrient removal modes, consisting of anaerobic, anoxic, and oxic sequences, were tested in a full-scale sequencing batch reactor. The modes, identified as BNR-S1 and BNR-S2, had average total nitrogen removals of 84 and 89%, respectively, for the months of August to October. Over the same period, total phosphorus removals for BNR-S1 and BNR-S2 were 88 and 87%, respectively. In contrast, total nitrogen and total phosphorus removals for the regular aerobic mode were 54.7 and 44.7%, respectively. When the wastewater temperature changed from approximately 20 to 15 degrees C in the winter months, total nitrogen and total phosphorus removals for BNR-S2 were reduced to 81 and 70%, respectively. Total nitrogen effluent concentrations were between 2.5 and 4 mg-N/L (at approximately 20 degrees C), while the effluent total phosphorus concentrations were between 1 and 2 mg/L. The BNR-S2 mode was found to require less energy per kilogram of soluble chemical oxygen demand removed than the regular and BNR-S1 modes.     

Application of magnetoelastic sensors for quantifying sediment deposition rates and sizes

This paper describes the application of magnetoelastic sensors for quantifying the size and deposition rate of sediment samples in costal areas, lakes, and rivers. The magnetoelastic sensor, which is made of inexpensive amorphous ferromagnetic alloy, measures parameters of interest by tracking the changes in its resonant frequency and/or amplitude. Since an increase in mass loading on the sensor surface changes its resonant frequency and amplitude, the deposition rate of sediment particles can be determined in real time by tracking these two quantities. Based on a theoretical model, the size distribution of the sediment particles was also estimated from the deposition rate.     

Biosorption study of potential fungi for copper remediation from Peninsular Malaysia

The ability to grow in heavy metal contaminated areas and absorb heavy metals from the environment make fungi a potentially viable biological‐based technology for remediating hazardous heavy metals in soil. In this study, 10 fungi from a copper (Cu)‐polluted area in Malaysia were isolated, with the four highest growth fungi identified as Simplicillium subtropicum, Fusarium solani, Aspergillus tamari, and Aspergillus niger. Results from toxicity and biosorption testing showed that A. niger and F. solani grew the fastest in the presence of Cu, but exhibited lower Cu uptake per unit of biomoass. In contrast, A. tamarii and S. subtropicum had lower growth rates, but showed better uptake of Cu per unit of biomass. S. subtropicum was identified as the best species for bioremediation because it had the highest Cu uptake and positive growth measured in the presence of Cu at concentrations below 100 mg/L. A niger proved to be most suitable for bioremediation if the concentration of Cu exceeds 100 mg/L.     

Advanced Aerogels from Wool Waste Fibers for Oil Spill Cleaning Applications

Journal of Polymers and the Environment - Oil spills causes severe degradation to marine ecosystems and poses long term health effects on many animals on the food chain, including humans. A...     

UVA-irradiated dual photoanodes and dual cathodes photocatalytic fuel cell: mechanisms and Reactive Red 120 degradation pathways

Environmental Science and Pollution Research - To enhance dye removal and energy recovery efficiencies in single-pair electrode photocatalytic fuel cell (PFC-AC), dual cathodes PFC (PFC-ACC) and...     

Degradation and metabolite production of tylosin in anaerobic and aerobic swine-manure lagoons.

Watershed contamination from antibiotics is becoming a critical issue because of increased numbers of confined animal-feeding operations and the use of antibiotics in animal production. To understand the fate of tylosin in manure before it is land-applied, degradation in manure lagoon slurries at 22 degrees C was studied. Tylosin disappearance followed a biphasic pattern, where rapid initial loss was followed by a slow removal phase. The 90% disappearance times for tylosin, relomycin (tylosin D), and desmycosin (tylosin B) in anaerobically incubated slurries were 30 to 130 hours. Aerating the slurries reduced the 90% disappearance times to between 12 and 26 hours. Biodegradation and abiotic degradation occur, but strong sorption to slurry solids was probably the primary mechanism of tylosin disappearance. Dihydrodesmycosin and an unknown degradate with molecular mass of m/z 934.5 were detected. Residual tylosin remained in slurry after eight months of incubation, indicating that degradation in lagoons is incomplete and that residues will enter agricultural fields.