Deposition regularity in a rainwater pipeline based on variable transport flux.

Experiments of the deposition of suspended particles in a rainwater pipeline were combined with mathematical model fitting to explore deposition regularity under variable transport flux. The simulation results showed that four primary factors affected deposition regularity in a rainwater pipeline. In particular, the deposition and flushing processes alternately dominated when the flow and initial suspended solids (SS) concentration changed simultaneously. The migration of the easy deposition position (EDP, the position with the largest deposition velocity) displayed an obvious regularity, shifting from front to back along the pipe regularly at increasing flow, and from back to front when flow decreased.

Risk assessment of heavy metals in road and soil dusts within PM2.5, PM10 and PM100 fractions in Dongying city, Shandong Province, China.

15 road and 14 soil dust samples were collected from an oilfield city, Dongying, from 11/2009-4/2010 and analyzed by inductively coupled plasma-mass spectroscopy (ICP-MS) for V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb within PM(2.5), PM(10) and PM(100) fractions synchronously. Metal concentrations, sources and human health risk were studied. Results showed that both soil and road dust exhibited higher values for Mn and Zn and lower values for Co and Cd for the three fractions. Mass concentration ratios of PM(2.5)/PM(10) and PM(10)/PM(100) for metals in road and soil dust indicate that most of the heavy metals tend to concentrate in fine particles. Geoaccumulation index and enrichment factors analysis showed that Cu, Zn and Cd exhibited moderate or heavy contamination and significant enrichment, indicating the influence of anthropogenic sources. Vanadium, Cr, Mn and Co were mostly not enriched and were mainly influenced by crustal sources. For Ni, As and Pb, they ranged from not enriched to moderately enriched and were influenced by both crustal materials and anthropogenic sources. The conclusions were confirmed by multivariate analysis methods. Principle component analysis revealed that the major sources were vehicle emission, industrial activities, coal combustion, agricultural activities and crustal materials. The risk assessment results indicated that metal ingestion appeared to be the main exposure route followed by dermal contact. The most likely cause for cancer and other health risks are both the fine particles of soil and road dusts.

Sequence variations in the mu-opioid receptor gene (OPRM1) associated with human addiction to heroin.

Human mu-opioid receptor (OPRM1) is the major site for the analgesic action of most opioid drugs such as morphine, methadone and heroin. It was previously reported that a single nucleotide polymorphism (SNP) in exon1 (c.118A-->G) of OPRM1 might modestly alter the affinity in beta-endorphin-Mu interaction. Using denaturing high performance liquid chromatography (DHPLC) the complete coding region of the OPRM1 gene was screened for SNPs in Han-Chinese heroin addicts and normal control. Three novel SNPs were detected, one in exon3, one in intron3 and one in the 3' untranslated region. The SNP c.118A-->G reportedly altered the interaction of Mu receptor with opioid had no statistically significant correlation with heroin addition in Han Chinese. However, addicted subjects with the SNP in intron2 (IVS2 +31G-->A) tended to show much higher heroin intake dosages than those without this SNP. We also observed that individuals carrying both SNP c.118A-->G and IVS2 +31G-->A consumed relatively more drugs compared to other addicts. Thus our study further highlights the importance of studing the various regions of the mu opioid receptor gene, coding as well as non-coding, for genetic markers that may be linked to, or directly contribute to opioid drug-seeking behavior.