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[en] Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants. Exposure to PAHs is associated with several adverse health outcomes. However, no previous study has examined the relationship between PAH exposure and functional dependence in an elderly population. Our aim was to examine whether PAH exposure was associated with functional dependence including total disability, activities of daily living (ADL), instrumental activities of daily living (IADL), leisure and social activities (LSA), lower extremity mobility (LEM), and general physical activities (GPA) in an elderly population. A total of 5816 elderly adults from the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2006 were examined. PAH exposure was measured by urinary biomarkers. Functional dependence was assessed by 19 structured questions. The association between PAH exposures with functional dependence was performed by using a multivariable linear regression model. After adjusting for pertinent variables, positive associations were observed between the total number of disabilities and 2-naphthalene and 1-pyrene quartiles (all Ptrend < 0.05). There was a dose-dependent relationship between 1-pyrene quartiles and all functional dependence domains, and the higher quartile of 1-pyrene was more closely associated with functional impairment (all Ptrend < 0.05). PAH exposure is associated with functional dependence in American elderly adults. Future research is needed to bring to light the pathophysiological underlying mechanisms related to these findings.
[en] Polycyclic aromatic hydrocarbons (PAHs) are a type of ubiquitous pollutant with the potential ability to cause endocrine disruption that would have an adverse health impact on the general population. To assess the maternal exposure to PAHs in neonates and evaluate the possible impact of PAHs on reproductive hormone levels, the concentration of PAHs and reproductive hormone levels in the umbilical cord serum of 98 mother-infant pairs in the Shengsi Islands were investigated. The median concentration of total PAHs was determined to be 164 (Inter-Quartile Range, IQR 93.6–267) ng g−1 lipid, and 68% of the PAHs were lower-molecule congeners. The highest level was found for pyrene (PYR) and naphthalene (NAP), which contributed 54.6% of all the PAHs present in the samples. The exposure to PAHs negatively affected estradiol (E2) and Anti-Mullerian hormones (AMH) and positively affected FSH in the umbilical cord serum. The result expanded the database of the human burden of PAHs and suggested that PAHs can act as a type of Endocrine-Disrupting Chemical (EDC). These results may help to understand the complex pathways involved in disorders of human reproductive health associated with prenatal exposure to PAHs. - Highlights: • The concentration of PAHs and reproductive hormones in cord serum were evaluated. • Low-molecular-weight types constitute 68% of total PAHs body burden in cord serum. • Correlations between reproductive hormone levels and PAHs levels were studied. • Environmental exposure to PAHs affected E2 and AMH negatively and FSH positively. • Database of body burden of PAHs expanded, implied that the PAHs act as a EDCs. - In cord serum, low-molecular-weight types constitute 68% of total PAHs body burden and PAHs affected reproductive hormone both positively and negatively.
[en] The occurrence and spatial distribution of polychlorinated naphthalenes (PCNs) were investigated in sediments, upland and paddy soils from the Liaohe River Basin. Concentrations of ΣPCNs were in the range of 0.33–12.49 ng g"−"1 dry weight (dw) in sediments and 0.61–6.60 ng g"−"1 dw in soils, respectively. Tri-CNs and tetra-CNs were the dominating homologues. An increasing trend of PCNs contamination was found in sediments with the rivers flowing through industrial areas and cities. Soils collected near cities exhibited higher abundance of PCNs than that of rural areas. The distribution of PCNs was related to the local industrial activities, rather than total organic carbon. Positive matrix factorization (PMF) was used for the source apportionment of PCNs in sediments and paddy soils. The result of PMF indicated that PCNs in sediments and paddy soils were mainly from the industrial processes, with additional contributions from the historical use of Halowax 1014 and atmospheric deposition. - Highlights: • Occurrence and distribution of PCNs were investigated in sediments and soils. • Tri-CNs and tetra-CNs were the dominating homologues. • Positive matrix factorization was used for the source apportionment of PCNs. • PCNs were mainly from the industrial processes. • Halowax 1014 and atmospheric deposition also contributed to PCNs pollution. - PCNs were less than 13.0 ng g"−"1 dw in sediments and soils from the Liaohe River Basin with the industrial processes as the major source.
[en] A new method based on passive samplers has been developed to assess the diffusive flux of fluorene, fluoranthene and pyrene in the sediment bed and across the sediment-water interface. The dissolved compound concentration gradient in the sediment in the vertical direction was measured at the outlet of a storm water pond by using polyethylene strips as passive samplers. Simultaneously, the dissipation of a set of tracer compounds preloaded in the passive samplers was measured to estimate the effective diffusion coefficients of the pollutants in the sediment. Both measurements were used to evaluate the diffusive flux of the compounds according to Fick's first law. The diffusive fluxes of the 3 studied compounds have been estimated with a centimetre-scale resolution in the upper 44 cm of the sediment. According to the higher compound diffusion coefficient and the steeper concentration gradient in the surficial sediment layer, the results show that the net flux of compounds near the sediment interface (1 cm depth) is on average 500 times higher than in the deep sediment, with average fluxes at 1 cm depth on the order of 5, 0.1 and 0.1 ng/m2/y for fluorene, fluoranthene and pyrene, respectively. - Highlights: • Pore water concentration gradients of a set of PAHs were measured by passive samplers. • The diffusivities of PAHs in the sediment were measured using tracer compounds. • The investigated PAHs were fluorene, fluoranthene and pyrene. • The selected tracer compounds were 2H-labelled versions of the same PAHs. • The diffusive fluxes in the sediment and near the interface were calculated.
[en] Two synthetic routes to 2,8-diaminoindeno-[1,2-b]fluorene are described. Device of the tetramethylation of terephthalate using Grignard reagent and the subsequent ring closure reaction of tertiary alcohol catalyzed by acid overcame the problems of harsh reaction conditions and low yields encountered in the previous synthesis. In particular, the second modified procedure is highly convergent-only five straightforward steps from commercially available. Conjugated aromatic compounds are potential candidates as organic semiconductors for use in thin-film transistors (TFTs) and light-emitting diodes (LEDs), among which the fluorene-based compounds have received most attention owing to their good availability and processability. Therefore, the synthesis of indenofluorene derivatives draws significant interest for their proper supply in both designing a new derivative and manufacturing
[en] The seismicity in the Pyrenees is continuous and well surveyed since more than 20 years. We use the catalogue of seismicity between 1997 and 2013 to explore the spatial variations of the b-value, which corresponds to the slope of the frequency-magnitude distribution of the earthquakes. Especially, variations of the b-value characterise the state of stress of the crust, possibly highlighting a deficit of large earthquake occurrence. We estimate the differential crustal stress from the b-value using a relationship published by Scholz (Geophys Res Lett 42:1399–1402, 2015). We also estimate the stress drop variations by determining a power law which links the magnitude to the seismic source radius in the Pyrenees. We focus on the depth variations and we analyse vertical profiles of b-value, differential stress and stress drop, first in the whole Pyrenean belt, then in 10 subregions. The b-values are generally smaller than 1, except in the uppermost 3–5 km where the obtained high values could be linked to the presence of fluids. Downward, the b-values decrease slowly or remain constant until a depth of increase, which could correspond to the brittle-ductile limit of the crust. We propose that this depth and the regional and vertical variations of the b-values are related to the regional tectonic context and possibly to the density heterogeneities. We also suggest that stress drop and differential stress are linearly correlated and that the stress drop is at least 1.8‰ of the differential stress.
[en] Highlights: • The transition between a fused-ring structure toward its single-ring counterpart is studied. • The change occurs at certain structure instead of a gradual transition. • The fused counterparts can be treated as a modification in the aromatic path of a single ring aromatic motif. • Useful approach to evaluate the formation of defects or larger-rings in graphene motifs. The fused-to-single-ring transition is studied through a 10πe series given the series from naphthalene to annulene. Our results suggest that change occurs at certain structure instead of a gradual transition. In the transition point, given by bicyclo[7.1.0]decapentaene, similar magnetic behavior in comparison to the single ring counterpart is found. The systems can be considered to behave as a whole single aromatic structure where the fused counterparts can be treated as a modification in the aromatic path of a single ring aromatic motif, which can viewed as a useful approach to evaluate the formation of defects or larger-rings in graphene motifs.
[en] 3D printing technique based on additive manufacturing can facilitate to manufacture plastic scintillators in innovatively fast time (10 minutes to 4 hours). For a practical use in radiation detection systems, 3D printed plastic scintillator has been studied to improve scintillation light output. In the previous study, it was confirmed that the amounts of 1-methyl-naphthlane in the composition of plastic scintillator improves light output of the scintillator. The measured data were compared to that of BC408 commercial plastic scintillator (Saint-Gobain Crystal). Light output and transmission of the 3D printed plastic scintillators with the different amounts of 1-methyl-naphthalene were measured and analyzed. The measured light output and transmission was improved with the amounts of 1-methyl-naphthalene, but the saturation of light output began above 1-methyl-naphthalene 60%. Given the above fact, it is expected that the additional effect factors on light output other than transmission should be considered such as the number of benzene rings in the composition of the scintillator and oxygen quenching effect.
[en] The scintillation of a material corresponds to the process of light emission after its excitation. In the context of dosimetry, ionizing radiation can excite the material and measure the luminous intensity resulting from correlation with a dose absorbed by the material. In this work, we produced a scintillation solution, using a solution of dichloromethane with anthracene as organic scintillator material, it has blue light emission after an excitation. To quantify the intensity of light as a function of the absorbed dose, use a digital camera (Nikon D90). The objective of this study was to evaluate the percentage depth dose for different kilovoltage beams. All the curves presented their maximum at 0.099 cm depth and the curves achieved for higher energies presented a high penetration power, indicating the potential of this technique for measurements of dose distributions in two dimensions. (author)