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51.
Health effects of ambient air pollution were studied in three groups of schoolchildren living in areas (suburban, urban and urban-traffic) with different air pollution levels in Eski?ehir, Turkey. This study involved 1,880 students aged between 9 and 13 years from 16 public primary schools. This two-season study was conducted from January 2008 through March 2009. Symptoms of asthma, rhinitis and eczema were determined by the International Study of Asthma and Allergies in Childhood questionnaire in 2008. Two lung function tests were performed by each child for summer and winter seasons with simultaneous ambient air measurements of ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2) by passive sampling. Effects of air pollution on impaired lung function and symptoms in schoolchildren were estimated by multivariate logistic regression analyses. Girls with impaired lung function (only for the summer season evaluation) were more observed in suburban and urban areas when compared to urban-traffic area ([odds ratio (OR)?=?1.49; 95 % confidence interval (CI) 1.04–2.14] and [OR?=?1.69 (95 % CI 1.06–2.71)] for suburban vs. urban-traffic and urban vs. urban-traffic, respectively). Significant association between ambient ozone concentrations and impaired lung function (for an increase of 10 μg m?3) was found only for girls for the summer season evaluation [OR?=?1.11 (95 % CI 1.03–1.19)]. No association was found for boys and for the winter season evaluation. No association was found between any of the measured air pollutants and symptoms of current wheeze, current rhinoconjunctivitis and current itchy rash. The results of this study showed that increasing ozone concentrations may cause a sub-acute impairment in lung function of school aged children.  相似文献   
52.
The potential utilization of burned wood in the manufacture of medium density fiberboard (MDF) was investigated. For this aim, the MDF panels were made of various mixtures of burned pine wood (Pinus sylvestris L.), unburned beech (Fagus orientalis L.) and oak (Ouercus robur L.) woods under commercial conditions in an MDF company. The mixture ratio of the unburned beech and oak woods to the burned pine wood were 50/50 wt%. The mixing ratios of burned wood chips with unburned wood chips were 0:100, 25:75, 50:50, 75:25 and 100:0, %, respectively. A commercial urea–formaldehyde resin was used as a binder. The physical properties measured in the investigation included density and thickness swelling, while the mechanical properties examined were bending strength, modulus elasticity, internal bond, screw holding ability perpendicular to the plane of panel, and janka hardness perpendicular to the plane of the panel. Surface roughness and color of the panels were also measured. The results indicated that all the panels met the mechanical properties of general-purpose MDF requirements of EN 622-5. The surface roughness of the MDF panels containing burned wood decreased with increasing burned wood content but remained higher than the control panels. The dimensional stability of the MDF panels decreased with the incorporation of burned wood fibers as compared with the control MDF panels.  相似文献   
53.
In this study, different concentrations of transfluthrin and metofluthrin have been assayed for genotoxicity by using the Wing Spot Test on Drosophila melanogaster. Standard cross was used in the experiment. Third-instar larvae that were trans-heterozygous for the two genetic markers mwh and flr3 were treated at different concentrations (0.0103 mg mL−1, 0.103 mg mL−1 for transfluthrin and 6 μg mL−1, 60 μg mL−1 for metofluthrin) of the test compounds. Feeding ended with pupation of the surviving larvae and the genetic changes induced in somatic cells of the wing’s imaginal discs lead to the formation of mutant clones on the wing blade. Results indicated that two experimental concentrations of transfluthrin and 60 μg mL−1 metofluthrin showed mutagenic and recombinogenic effects in both the marker-heterozygous (MH) flies and the balancer-heterozygous (BH) flies.  相似文献   
54.
The accumulations of Al, Cd, Cr, Cu, Fe, Ni, Pb and Zn in the exoskeleton, gills, hepatopancreas and abdominal muscles of crayfish Astacus leptodactylus (Eschscholtz, 1823) were determined. The strongest correlation observed was between Cr and Ni in the gills (r?=?0.904); moderate to strong correlations between Al, Cr, Fe, Ni and Cu were also observed in gill tissue. Disregarding the gills, the strongest correlation was found between Cu and Zn in the hepatopancreas (r?=?0.808); the correlation between these two metals might have been a result of metallothionein activity. The accumulation of Pb was found to correlate with that of Cd in the exoskeleton, Cd and Zn in the gills, Zn and Cu in the hepatopancreas and Cu in the abdominal muscle. None of these correlations were present in lakewater and sediment samples, suggesting that the crayfish metabolism may be responsible for the co-accumulation of metal–metal pairs. As all correlations in non-gill tissues are observed between divalent metals, a shared transporter such as divalent metal transporter 1 might be involved in the accumulation of these metals.  相似文献   
55.
Acoustic Doppler current meters (ADV, ADCP, and ADP) are widely used in water systems to measure flow velocities and velocity profiles. Although these meters are designed for flow velocity measurements, they can also provide information defining the quantity of particulate matter in the water, after appropriate calibration. When an acoustic instrument is calibrated for a water system, no additional sensor is needed to measure suspended sediment concentration (SSC). This provides the simultaneous measurements of velocity and concentration required for most sediment transport studies. The performance of acoustic Doppler current meters for measuring SSC was investigated in different studies where signal-to-noise ratio (SNR) and suspended sediment concentration were related using different formulations. However, these studies were each limited to a single study site where neither the effect of particle size nor the effect of temperature was investigated. In this study, different parameters that affect the performance of an ADV for the prediction of SSC are investigated. In order to investigate the reliability of an ADV for SSC measurements in different environments, flow and SSC measurements were made in different streams located in the Aegean region of Turkey having different soil types. Soil samples were collected from all measuring stations and particle size analysis was conducted by mechanical means. Multivariate analysis was utilized to investigate the effect of soil type and water temperature on the measurements. Statistical analysis indicates that SNR readings ob tained from the ADV are affected by water temperature and particle size distribution of the soil, as expected, and a prediction model is presented relating SNR readings to SSC mea surements where both water temperature and sediment characteristics type are incorporated into the model. The coefficients of the suggested model were obtained using the multivariate anal ysis. Effect of high turbidity conditions on ADV performance was also investigated during and after rain events.  相似文献   
56.
Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation.  相似文献   
57.
58.
Shortage in phosphorus(P) resources and P wastewater pollution is considered as a serious problem worldwide. The application of modified biochar for P recovery from wastewater and reuse of recovered P as agricultural fertilizer is a preferred process. This work aims to develop a calcium and magnesium loaded biochar(Ca–Mg/biochar) application for P recovery from biogas fermentation liquid. The physico-chemical characterization, adsorption efficiency, adsorption selectivity, and postsorption availability of Ca-Mg/biochar were investigated. The synthesized Ca–Mg/biochar was rich in organic functional groups and in Ca O and Mg O nanoparticles. With the increase in synthesis temperature, the yield decreased, C content increased, H content decreased, N content remained the same basically, and BET surface area increased. The P adsorption of Ca–Mg/biochar could be accelerated by nano-Ca O and nano-Mg O particles and reached equilibrium after 360 min.The process was endothermic, spontaneous, and showed an increase in the disorder of the solid–liquid interface. Moreover, it could be fitted by the Freundlich model. The maximum P adsorption amounts were 294.22, 315.33, and 326.63 mg/g. The P adsorption selectivity of Ca–Mg/biochar could not be significantly influenced by the typical p H level of biogas fermentation liquid. The nano-Ca O and nano-Mg O particles of Ca–Mg/biochar could reduce the negative interaction effects of coexisting ions. The P releasing amounts of postsorption Ca–Mg/biochar were in the order of Ca–Mg/B600 Ca–Mg/B450 Ca–Mg/B300. Results revealed that postsorption Ca–Mg/biochar can continually release P and is more suitable for an acid environment.  相似文献   
59.
Iniencephaly is a rare and lethal congenital malformation of the neural tube characterized by occipital bone defect, cervical dysraphism, fixed retroflexion of the fetal head and severe lordosis of the cervicothoracic spine. The etiology is unknown. Prenatally diagnosed cases of iniencephaly are rare because careful and early ultrasonographic evaluation is necessary. We present three cases of iniencephaly prenatally diagnosed by sonography at 20–22 weeks' gestation in which therapeutic abortion was induced. The sonographic findings were compatible with the postmortem findings. The present cases of iniencephaly were found to carry unusual associated malformations such as two lobes in the right lung and chorangiosis of the placenta. Only hypoplastic lungs have been reported by previous authors. We also studied the 677C→T mutation on the methylenetetrahydrofolate reductase gene in the parents in one of the present cases. The mother was found to be heterozygous for the 677CT polymorphism. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
60.
In this study, the composition of vinasse was first analysed. It was found to contain 8.43% dry matter, 3.3% total ash, 4% crude protein and 0.95% total carbohydrates; BOD load was determined as 63 g litre(-1). Subsequently, the effects of vinasse in various concentrations (1, 2.5, 5, 10, 25, 50, 75 and 100%) on the activity of cellulase and pectin methyl esterase and the chlorophyll and protein contents of Pisum sativum and Helianthus annuus were investigated. The activity of these enzymes and the protein and chlorophyll contents in potted plants showed a gradual increase from the control up to 2.5% concentration of vinasse, but decreased at higher concentrations. These different effects of the effluent may be due to the high BOD load and the presence of cell wall cations in it.  相似文献   
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