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Результаты 3911-3920 из 4,924
Fine particulate matter alters the microecology of the murine respiratory tract
2019
Yang, Biao | Zhang, Yu | Li, Bingyu | Zou, Yang | Xiao, Chunling
Fine particulate matter is a global challenge to human health. We investigated the effects and potential mechanisms of fine particulate matter on respiratory tract microecology in a lung injury mouse model. BALB/c mice were randomized into exposed and control groups. We found that the levels of soluble tumor necrosis factor receptor I was increased following the PM2.5 exposure. 16S rRNA sequencing of respiratory tract lavage fluid confirmed that the composition of the respiratory tract microecology was altered by the exposure. Lactobacillus was the most abundant of bacterial species present. Collectively, these results establish a link between exposure to fine particulate matter and alterations to the respiratory tract microecology. Elucidation of the underlying mechanisms may lead to treatment strategies in lung injury.
Показать больше [+] Меньше [-]A mini review of bisphenol A (BPA) effects on cancer-related cellular signaling pathways
2019
Nomiri, Samira | Hoshyar, Reyhane | Ambrosino, Concetta | Tyler, Charles R. | Mansouri, Borhan
Bisphenol A (BPA) is a plasticizer used widely in many industrial products and is now well established as an endocrine-disrupting chemical (EDC). BPA readily leaches out from these products into the environment and into foodstuffs (from packaging materials) and human exposure can be considerable. Many studies have shown that BPA exposure is associated with a range of chronic human health conditions, including diabetes, cardiovascular disorders, polycystic ovarian disease, hepatotoxicity, and various types of cancer. BPA exerts its effects through deregulating cell signaling pathways associated with cell growth, proliferation, migration, invasion, and apoptosis. Previous studies on the molecular mechanisms of BPA have illustrated a variety of pathways impaired at very low exposure concentrations and that stimulate cellular responses relating to tumorigenesis both in cancer onset and progression. In this mini review, the recent advancements made through in vitro analyses are reported on for the effect of BPA on various cellular signaling pathways focusing on the signaling pathways that play a major role in carcinogenesis.
Показать больше [+] Меньше [-]Endocrine disrupting pesticides in soil and their health risk through ingestion of vegetables grown in Pakistan
2019
Ali, Neelum | K̲h̲ān, Sardār | Khan, Muhammad Amjad | Waqas, Muhammad | Yao, Huaiying
A comprehensive study was conducted to appraise the concentrations of 30 endocrine disrupting pesticides (EDPs) in soil and vegetable samples collected from Khyber Pakhtunkhwa, Pakistan. The sum of 30 EDPs (Σ₃₀EDPs) ranged from 192 to 2148 μg kg⁻¹ in the collected soils. The selected EDP concentrations exceeded their respective limits in most of the tested soils and showed great variation from site to site. Similarly, high variations in Σ₃₀EDP concentrations were also observed in vegetables with the highest mean concentration in lettuce (28.9 μg kg⁻¹), followed by radish (26.6 μg kg⁻¹), spinach (25.7 μg kg⁻¹), onion (16.2 μg kg⁻¹), turnip (15.6 μg kg⁻¹), and garlic (14.7 μg kg⁻¹). However, EDP levels in all studied vegetables were within FAO/WHO limits. The mean bioconcentration factor values were observed < 1 for all the studied vegetables. The health risk assessment revealed that the incremental lifetime cancer risk (ILCR) of Σ₃₀EDPs associated with vegetable ingestion was below the acceptable risk level (1 × 10⁻⁶), showing no cancer risk to local inhabitants. However, exposure to endocrine disruptor and probable carcinogen heptachlor epoxide poses a potential non-cancer risk (hazard quotient (HQ > 1)) to children through vegetable consumption. The presence of banned EDPs in soils and vegetables of the study area indicates the stability of these legacy chemicals in the environment from over usage in the past or illegal current application for agricultural purposes. Graphical abstract
Показать больше [+] Меньше [-]Differences of methods to quantify construction and demolition waste for less-developed but fast-growing countries: China as a case study
2019
Zhang, Ning | Zheng, Lina | Duan, Huabo | Yin, Fengfu | Li, Jiabin | Niu, Yongning
As China and other developing countries continue to urbanize over the next decades, construction and demolition waste (CDW) management has been becoming a significant challenge for urban sustainability in terms of the environment, economy, and safety. However, accurate estimations or statistics of CDW generation are absent from the official national report in spite of their importance to devise sensible interventions to tackle CDW-related problems. This paper examines and compares the applications of three prevailing methods for estimating CDW, including the weight-per-construction-area method (WAM), buildings’ life span-based method, and weight-per-capita method. Specifically, China has been chosen as the case study. This study implies that the weight-per-construction-area method is more appropriate because of the data availability and accuracy at a city or national level. The results of WAM indicate that a total of 4.1 billion metric tons (Bt) of CDW were generated in China in 2016, mainly from demolition waste (85%). Taking the changes of buildings’ life span into account, a projection analysis reveals that the cumulative CDW generation will be 50 Bt between 2017 and 2040 in China (equal to approximately 38 years cumulative generation of global municipal solid waste). Overall, the findings provide some methodological options for scholars, practitioners, and decision-makers to more accurately estimate the amount of the CDW and to develop a more environmentally sound management strategy.
Показать больше [+] Меньше [-]Comparison of biochar- and activated carbon-supported zerovalent iron for the removal of Se(IV) and Se(VI): influence of pH, ionic strength, and natural organic matter
2019
Tan, Guangcai | Mao, Yi | Wang, Hongyuan | Junaid, Muhammad | Xu, Nan
Biochar (BC) and activated carbon (AC) were both produced from corn straw. Biochar-supported zerovalent iron (BC-ZVI) and activated carbon-supported zerovalent iron (AC-ZVI) were synthesized and applied for Se(IV)/Se(VI) removal. The sorption capacity of BC-ZVI for Se(IV) and Se(VI) was reported at 62.52 and 35.39 mg g⁻¹, higher than that of AC-ZVI (56.02 and 33.24 mg g⁻¹), respectively, due to its higher iron content and more positive charges. The spectroscopic analyses showed that Se(IV)/Se(VI) were reduced to Se(0)/Se(-II) of less toxicity and solubility. The effects of various factors such as pH, ionic strength, co-existing cations and anions, and natural organic matter (NOM) were also investigated. Ionic strength showed no significant effect on Se(IV)/Se(VI) removal, but pH was critical. The presence of NO₃⁻ and SO₄²⁻ did not cause obvious inhibition to the removal, while PO₄³⁻ inhibited the sorption capacity of BC-ZVI and AC-ZVI for Se(IV)/Se(VI) significantly. Common cations (K⁺, Ca²⁺, and Mg²⁺) were found to slightly enhance the removal, while NOM significantly decreased the sorption capacity of BC-ZVI and AC-ZVI for Se(IV)/Se(VI). Besides, NOM showed stronger inhibition effect on AC-ZVI than that on BC-ZVI. These results indicated that BC-ZVI, compared with AC-ZVI, could be a promising sorbent to remove Se(IV)/Se(VI) due to its low cost and high efficiency.
Показать больше [+] Меньше [-]Effective cleanup of oil contamination on bio-inspired superhydrophobic surface
2019
Zhou, Qin | Wang, Leyang | Xu, Qi | Zhao, Yuan
The oil-water separation is a popular issue and the removal of oil from bulk water is also meaningful especially in oil spill incident, which not only wastes valuable energy resources but also threatens the ecological system and human health. Superhydrophobic and superoleophilic materials are very promising for the efficient oil removal from bulk water. Reported herein was a novel and easily operated superhydrophobic surface dip coating from a paint-like suspension containing two different sizes TiO₂ and perfluorooctyltriethoxysilane. Aluminum foil substrate, which is flexile and cost-efficient, was bonded with commercial water-proof double-sided adhesive tape (DSAT) to fix the paint to improve the mechanical strength. The coated aluminum foil exhibited rapid sorption/desorption rate (267 L/h m²), high oil sorption capacity (21 g/g), and excellent recyclability (≫ 15 recycling times). After 15 recycling times of sorption/desorption, the coated surface morphology still remained hierarchical micro- and nanostructures and the water contact angle still reached ~ 150°, indicating its superhydrophobic property. Meanwhile, the cost of oil removal of the coated material can match that of the commercial sorbent. We anticipate that the coated superhydrophobic aluminum foil will show outstanding performances on oil absorption and have good applications on a large scale.
Показать больше [+] Меньше [-]Review on the determination and distribution patterns of a widespread contaminant artificial sweetener in the environment
2019
Luo, Jingyang | Wu, Lijuan | Zhang, Qin | Wu, Yang | Fang, Fang | Feng, Qian | Li, Chao | Xue, Zhaoxia | Cao, Jiashun
The accurate determination of widespread artificial sweeteners (ASs) and the information of their distributions in environments are of significance to investigate the environmental behaviors. This paper firstly reviews the typical analytic methodologies for ASs and the main influencing factors during the analytic processes. Solid-phase extraction (SPE) with LC-ESI-MS is currently the leading-edge method. However, the efficiency and accuracy for ASs analysis in environmental samples are also dependent on the SPE cartridges, buffers and pH, matrix effects, and sample stability. A basic procedure for ASs determination in different environmental samples is proposed. The current occurrences of ASs in environments are then evaluated. The ASs, especially the acesulfame and sucralose, are widely detected in various environmental medium. The concentrations of investigated ASs are generally in the order of wastewater treatment plants (WWTPs) influent > WWTPs effluent > surface water > groundwater > drinking water; and atmosphere > soil. The ASs levels in the environment exhibit significant differences among different regions. Further analysis indicates that the phenomenon is highly correlated with the consumption patterns and the removal efficiency of WWTPs in a specific country.
Показать больше [+] Меньше [-]Response of secondary metabolites to Cu in the Cu-hyperaccumulator lichen Stereocaulon japonicum
2019
Nakajima, Hiromitsu | Fujimoto, Naoki | Yamamoto, Yoshikazu | Amemiya, Takashi | Itoh, Kiminori
Lichen secondary metabolites are known to be associated with heavy metal uptake and tolerance in lichens. Understanding the relationship between their secondary metabolites and heavy metals in them is important for clarifying the mechanisms of their heavy metal accumulation and tolerance. To determine the relationships between the concentrations of secondary metabolites and Cu in the Cu-hyperaccumulator lichen Stereocaulon japonicum and to clarify its response to Cu, we collected Cu-contaminated and uncontaminated samples of the lichen and determined relative concentrations of secondary metabolites and concentrations of Cu, K, glucose, and sugar alcohols in them. We found significant negative correlations between the relative concentrations of secondary metabolites—atranorin and stictic acid—and the concentration of Cu. These negative correlations can be interpreted in one of two ways: (a) S. japonicum itself reduced the relative concentrations of secondary metabolites in response to the increase of Cu concentration or (b) its carbon and energy metabolism was damaged by Cu stress, resulting in the reduction of the relative concentrations of secondary metabolites. The analysis of K, glucose, and sugar alcohols showed no effect of Cu on these concentrations, which means that the carbon and energy metabolism was not damaged by Cu stress. Therefore, the negative correlations can be interpreted that S. japonicum itself reduced the relative concentrations of secondary metabolites with the increase of Cu concentration. These findings provide a deeper understanding of the response of secondary metabolites to Cu in the lichen.
Показать больше [+] Меньше [-]Magnetic characteristics of Juniperus formosana needles along an urban street in Lanzhou, Northwest China: the variation of different season and orientation
2019
Chen, Hong | Wang, Bo | Xia, Dun-sheng | Fan, Yi-jiao | Liu, Hui | Tang, Zhi-rong | Ma, Shan
The magnetic properties of particulate matter (PM) deposited on the needles of Juniperus formosana along an urban street in Lanzhou city were measured to evaluate the variations of PM concentration in different seasons by varying distance from the road. The magnetism of PM deposited in this context was significantly higher in winter than in summer, which may reflect changes of atmospheric particle concentrations. Needle samples which were collected from the road-facing side exhibiting significantly stronger magnetism compared with those which were collected from the opposite side of the road, indicating the distance from pollution source to the needles as a factor controls the amount of PM. The results of this study show that the needles of Juniperus formosana are effective traps for PM and can therefore be used to monitor pollution fluxes in different seasons in an important urban context in NW China.
Показать больше [+] Меньше [-]High rice husk ash doses applied to the soil can lead to phosphorus water contamination
2019
da Silva Teixeira, Juliana Brito | Islabão, Glaucia Oliveira | Vahl, Ledemar Carlos | Guidotti, Rosane | Kath, Aline Hernandez | de Sousa Oliveira, Rogerio
The goal of this work was to evaluate the rice husk ash (RHA) effect on soil phosphorus (P) adsorption and to analyze the probable consequences of these in the parameters that affect P availability to the plants and the risk of soil P loss by superficial run-off. For this, a factorial experiment was conducted in laboratory with samples of two soils (factor A: Hapludult and Hapludox) that were submitted to five doses of RHA (factor B: 0; 25; 50; 75 and 100 g RHA kg⁻¹ of soil). The experimental units were plastic pots with 200 g of air-dry fine earth from horizon A of each soil. The experimental design was completely random with three replications. After 30 days of soils incubation where moisture was maintained in field capacity, the phosphorus adsorption isotherms were made in subsamples of each experimental unit. The RHA decreases sharply the phosphorus adsorption power but decreases very little the maximum soil phosphate adsorption. The RHA increases the soluble silicium and phosphorus contents, but these are not responsible for the decrease in phosphorus adsorption later applied in the soil. The major cause of the negative effect of RHA in the soil phosphate adsorption is the increase in soil pH. As a consequence of these effects, the RHA decreases the buffering ability and increases the phosphorus effective diffusion coefficient in the soil. Moreover, as a consequence of the adsorption power decrease, the RHA increases the risk of environmental contamination by phosphorus by superficial runoff, especially in soils with originally low phosphorus adsorption ability.
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