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Ambient carbon monoxide associated with alleviated respiratory inflammation in healthy young adults
2016
Zhao, Zhuohui | Chen, Renjie | Lin, Zhijing | Cai, Jing | Yang, Yingying | Yang, Dandan | Norbäck, Dan | Kan, Haidong
There is increasing controversy on whether acute exposure to ambient carbon monoxide (CO) is hazardous on respiratory health. We therefore performed a longitudinal panel study to evaluate the acute effects of ambient CO on fractional exhaled nitric oxide (FeNO), a well-established biomarker of airway inflammation. We completed 4–6 rounds of health examinations among 75 healthy young adults during April to June in 2013 in Shanghai, China. We applied the linear mixed-effect model to investigate the short-term associations between CO and FeNO. CO exposure during 2–72 h preceding health tests was significantly associated with decreased FeNO levels. For example, an interquartile range increase (0.3 mg/m³) of 2-h CO exposure corresponded to 10.6% decrease in FeNO. This association remained when controlling for the concomitant exposure to co-pollutants. This study provided support that short-term exposure to ambient CO might be related with reduced levels of FeNO, a biomarker of lower airway inflammation.
Show more [+] Less [-]Association of urinary metals levels with type 2 diabetes risk in coke oven workers
2016
Liu, Bing | Feng, Wei | Wang, Jing | Li, Yaru | Han, Xu | Hu, Hua | Kwok, Woon | Zhang, Xiaomin | He, Meian
Studies indicated that occupationally exposed to metals could result in oxidative damage and inflammation and increase cardiovascular diseases risk. However, epidemiological studies about the associations of metals exposure with diabetes risk among coke oven workers were limited.This study aims to investigate the potential associations of 23 metals levels with the risk of diabetes among coke oven workers.The analysis was conducted in a cross-sectional study including 1493 participants. Urinary metals and urinary polycyclic aromatic hydrocarbons (PAHs) metabolites levels were determined by inductively coupled plasma mass spectrometer and gas chromatograph-mass spectrometer respectively. Multivariate logistic regression was used to investigate the associations of urinary metal levels with diabetes risk with adjustment for potential confounding factors including gender, age, BMI, education, smoking, drinking, physical activity, hypertension, hyperlipidemia and urinary PAHs metabolites levels.Compared with the normoglycemia group, the levels of urinary copper, zinc, arsenic, selenium, molybdenum, and cadmium were significantly higher in the diabetes group (all p < 0.05). Participants with the highest tertile of urinary copper and zinc had 2.12 (95%CI: 1.12–4.01) and 5.43 (95%CI: 2.61–11.30) fold risk of diabetes. Similar results were found for hyperglycemia risk. Besides, participants with the highest tertile of manganese, barium, and lead had 1.65(1.22–2.23), 1.60(1.19–2.16) and 1.45(1.05–1.99) fold risk of hyperglycemia when compared with the lowest tertlie.The results indicated that the urinary copper and zinc levels were positively associated with the risk of diabetes and hyperglycemia among coke oven workers. Urinary manganese, barium and lead levels were also associated with increased risk of hyperglycemia independently of other traditional risk factors. These findings need further validation in prospective study with larger sample size.
Show more [+] Less [-]The impact of traffic-flow patterns on air quality in urban street canyons
2016
Thaker, Prashant | Gokhale, Sharad
We investigated the effect of different urban traffic-flow patterns on pollutant dispersion in different winds in a real asymmetric street canyon. Free-flow traffic causes more turbulence in the canyon facilitating more dispersion and a reduction in pedestrian level concentration. The comparison of with and without a vehicle-induced-turbulence revealed that when winds were perpendicular, the free-flow traffic reduced the concentration by 73% on the windward side with a minor increase of 17% on the leeward side, whereas for parallel winds, it reduced the concentration by 51% and 29%. The congested-flow traffic increased the concentrations on the leeward side by 47% when winds were perpendicular posing a higher risk to health, whereas reduced it by 17–42% for parallel winds. The urban air quality and public health can, therefore, be improved by improving the traffic-flow patterns in street canyons as vehicle-induced turbulence has been shown to contribute significantly to dispersion.
Show more [+] Less [-]Spatio-temporal behavior of brightness temperature in Tel-Aviv and its application to air temperature monitoring
2016
Pelta, Ran | Chudnovsky, A Alexandra | Schwartz, Joel
This study applies remote sensing technology to assess and examine the spatial and temporal Brightness Temperature (BT) profile in the city of Tel-Aviv, Israel over the last 30 years using Landsat imagery. The location of warmest and coldest zones are constant over the studied period. Distinct diurnal and temporal BT behavior divide the city into four different segments. As an example of future application, we applied mixed regression models with daily random slopes to correlate Landsat BT data with monitored air temperature (Tair) measurements using 14 images for 1989–2014. Our preliminary results show a good model performance with R² = 0.81. Furthermore, based on the model's results, we analyzed the spatial profile of Tair within the study domain for representative days.
Show more [+] Less [-]Adsorption and desorption of arsenate on sandy sediments from contaminated and uncontaminated saturated zones: Kinetic and equilibrium modeling
2016
Hafeznezami, Saeedreza | Zimmer-Faust, Amity G. | Dunne, Aislinn | Tran, Tiffany | Yang, Chao | Lam, Jacquelyn R. | Reynolds, Matthew D. | Davis, James A. | Jay, Jennifer A.
Application of empirical models to adsorption of contaminants on natural heterogeneous sorbents is often challenging due to the uncertainty associated with fitting experimental data and determining adjustable parameters. Sediment samples from contaminated and uncontaminated portions of a study site in Maine, USA were collected and investigated for adsorption of arsenate [As(V)]. Two kinetic models were used to describe the results of single solute batch adsorption experiments. Piecewise linear regression of data linearized to fit pseudo-first order kinetic model resulted in two distinct rates and a cutoff time point of 14–19 h delineating the biphasic behavior of solute adsorption. During the initial rapid adsorption stage, an average of 60–80% of the total adsorption took place. Pseudo-second order kinetic models provided the best fit to the experimental data (R2 > 0.99) and were capable of describing the adsorption over the entire range of experiments. Both Langmuir and Freundlich isotherms provided reasonable fits to the adsorption data at equilibrium. Langmuir-derived maximum adsorption capacity (St) of the studied sediments ranged between 29 and 97 mg/kg increasing from contaminated to uncontaminated sites. Solid phase As content of the sediments ranged from 3.8 to 10 mg/kg and the As/Fe ratios were highest in the amorphous phase. High-pH desorption experiments resulted in a greater percentage of solid phase As released into solution from experimentally-loaded sediments than from the unaltered samples suggesting that As(V) adsorption takes place on different reversible and irreversible surface sites.
Show more [+] Less [-]Simultaneous removal of acid green 25 and mercury ions from aqueous solutions using glutamine modified chitosan magnetic composite microspheres
2016
Tao, Xue | Li, Kun | Yan, Han | Yang, Hu | Li, Aimin
In this current work, the magnetic composite microsphere containing glutamine modified chitosan and silica coated Fe3O4 nanoparticles (CS-Gln-MCM) has been successfully prepared and extensively characterized, which is a kind of biodegradable materials. CS-Gln-MCM shows enhanced removal efficiency for both acid green 25 (AG25), an amphoteric dye, and mercury ions (Hg²⁺) from water in the respective while measured pH range compared with chitosan magnetic composite microsphere (CS-MCM) without modification. It is due to the fact that the grafted amino acid provides a variety of additional adsorption active sites and diverse adsorption mechanisms are involved. In AG25 and Hg²⁺ aqueous mixture, the modified adsorbents bear preferential adsorption for AG25 over Hg²⁺ in strong acidic solutions ascribed to multiple interactions between AG25 and CS-Gln-MCM, such as hydrogen bonding and electrostatic interactions. While, in weak acidic conditions, an efficient simultaneous removal is observed for different adsorption effects involved in aforementioned two pollutants. Besides, CS-Gln-MCM illuminates not only short equilibrium time for adsorption of each pollutant less than 20.0 min but also rapid magnetic separation from water and efficient regeneration after saturated adsorption. Therefore, CS-Gln-MCM bears great application potentials in water treatment.
Show more [+] Less [-]Nano-TiO2 affects Cu speciation, extracellular enzyme activity, and bacterial communities in sediments
2016
Fan, Wenhong | Liu, Tong | Li, Xiaomin | Peng, Ruishuang | Zhang, Yilin
In aquatic ecosystems, titanium dioxide nanoparticles (nano-TiO2) coexist with heavy metals and influence the existing forms and toxicities of the metal in water. However, limited information is available regarding the ecological risk of this coexistence in sediments. In this study, the effect of nano-TiO2 on Cu speciation in sediments was investigated using sequential extraction. The microcosm approach was also employed to analyze the effects of the coexistence of nano-TiO2 and Cu on extracellular enzyme activity and bacterial communities in sediments. Results showed that nano-TiO2 decreased the organic matter-bound fraction of Cu and increased the corresponding residual fraction Cu. As a result, speciation of exogenous Cu in sediments changed. During the course of the 30-day experiment, the presence of nano-TiO2 did not affect Cu-induced changes in bacterial community structure. However, the coexistence of nano-TiO2 and Cu restrained the activity of bacterial extracellular enzymes, such as alkaline phosphatase and β-glucosidase. The degree of inhibition also varied because of the different properties of extracellular enzymes. This research highlighted the importance of understanding and predicting the effects of the coexistence of nanomaterials and other pollutants in sediments.
Show more [+] Less [-]Delayed effects of chlorpyrifos across metamorphosis on dispersal-related traits in a poleward moving damselfly
2016
Dinh, Khuong Van | Janssens, Lizanne | Therry, Lieven | Bervoets, Lieven | Bonte, Dries | Stoks, Robby
How exposure to contaminants may interfere with the widespread poleward range expansions under global warming is largely unknown. Pesticide exposure may negatively affect traits shaping the speed of range expansion, including traits related to population growth rate and dispersal-related traits. Moreover, rapid evolution of growth rates during poleward range expansions may come at a cost of a reduced investment in detoxification and repair thereby increasing the vulnerability to contaminants at expanding range fronts. We tested effects of a sublethal concentration of the widespread pesticide chlorpyrifos on traits related to range expansion in replicated edge and core populations of the poleward moving damselfly Coenagrion scitulum reared at low and high food levels in a common garden experiment. Food limitation in the larval stage had strong negative effects both in the larval stage and across metamorphosis in the adult stage. Exposure to chlorpyrifos during the larval stage did not affect larval traits but caused delayed effects across metamorphosis by increasing the incidence of wing malformations during metamorphosis and by reducing a key component of the adult immune response. There was some support for an evolutionary trade-off scenario as the faster growing edge larvae suffered a higher mortality during metamorphosis. Instead, there was no clear support for the faster growing edge larvae being more vulnerable to chlorpyrifos. Our data indicate that sublethal delayed effects of pesticide exposure, partly in association with the rapid evolution of faster growth rates, may slow down range expansions.
Show more [+] Less [-]A review of nickel toxicity to marine and estuarine tropical biota with particular reference to the South East Asian and Melanesian region
2016
Gissi, Francesca | Stauber, Jennifer L. | Binet, Monique T. | Golding, Lisa A. | Adams, Merrin S. | Schlekat, Christian E. | Garman, Emily R. | Jolley, Dianne F.
The South East Asian Melanesian (SEAM) region contains the world's largest deposits of nickel lateritic ores. Environmental impacts may occur if mining operations are not adequately managed. Effects data for tropical ecosystems are required to assess risks of contaminant exposure and to derive water quality guidelines (WQG) to manage these risks. Currently, risk assessment tools and WQGs for the tropics are limited due to the sparse research on how contaminants impact tropical biota. As part of a larger project to develop appropriate risk assessment tools to ensure sustainable nickel production in SEAM, nickel effects data were required. The aim of this review was to compile data on the effects of nickel on tropical marine, estuarine, pelagic and benthic species, with a particular focus on SEAM.There were limited high quality chronic nickel toxicity data for tropical marine species, and even fewer for those relevant to SEAM. Of the data available, the most sensitive SEAM species to nickel were a sea urchin, copepod and anemone. There is a significant lack of high quality chronic data for several ecologically important taxonomic groups including cnidarians, molluscs, crustaceans, echinoderms, macroalgae and fish. No high quality chronic nickel toxicity data were available for estuarine waters or marine and estuarine sediments. The very sparse toxicity data for tropical species limits our ability to conduct robust ecological risk assessment and may require additional data generation or read-across from similar species in other databases (e.g. temperate) to fill data gaps. Recommendations on testing priorities to fill these data gaps are presented.
Show more [+] Less [-]Physiological and genotype-specific factors associated with grain quality changes in rice exposed to high ozone
2016
Jing, Liquan | Dombinov, Vitalij | Shen, Shibo | Wu, Yanzhen | Yang, Lianxin | Wang, Yunxia | Frei, Michael
Rising tropospheric ozone concentrations in Asia affect the yield and quality of rice. This study investigated ozone-induced changes in rice grain quality in contrasting rice genotypes, and explored the associated physiological processes during the reproductive growth phase. The ozone sensitive variety Nipponbare and a breeding line (L81) containing two tolerance QTLs in Nipponbare background were exposed to 100 ppb ozone (8 h per day) or control conditions throughout their growth. Ozone affected grain chalkiness and protein concentration and composition. The percentage of chalky grains was significantly increased in Nipponbare but not in L81. Physiological measurements suggested that grain chalkiness was associated with a drop in foliar carbohydrate and nitrogen levels during grain filling, which was less pronounced in the tolerant L81. Grain total protein concentration was significantly increased in the ozone treatment, although the albumin fraction (water soluble protein) decreased. The increase in protein was more pronounced in L81, due to increases in the glutelin fraction in this genotype. Amino acids responded differently to the ozone treatment. Three essential amino acids (leucine, methionine and threonine) showed significant increases, while seven showed significant treatment by genotype interactions, mostly due to more positive responses in L81. The trend of increased grain protein was in contrast to foliar nitrogen levels, which were negatively affected by ozone. A negative correlation between grain protein and foliar nitrogen in ozone stress indicated that higher grain protein cannot be explained by a concentration effect in all tissues due to lower biomass production. Rather, ozone exposure affected the nitrogen distribution, as indicated by altered foliar activity of the enzymes involved in nitrogen metabolism, such as glutamine synthetase and glutamine-2-oxoglutarate aminotransferase. Our results demonstrate differential responses of grain quality to ozone due to the presence of tolerance QTL, and partly explain the underlying physiological processes.
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