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Fractionation and chemical structure of dissolved organic matter in the rhizosphere associated with cadmium accumulation in tobacco lines (Nicotiana tabacum L.) Full text
2020
Zhao, Ming | Li, Tingxuan | Yu, Haiying | Zhang, Xizhou | Zheng, Zicheng | Wang, Yongdong | Liu, Tao | Gupta, Dharmendra K. | Huang, Huagang
Reducing cadmium (Cd) accumulation in flue-cured tobacco is the main degree to reduce the harm of Cd to human health. In this study, a rhizobag experiment was conducted to investigate the characteristics of dissolved organic matter (DOM) in the rhizosphere of a low-Cd-accumulating tobacco line (RG11) and its role in the processes of Cd accumulation by plants. Cd concentrations in the roots and leaves of RG11 were 24.09–25.30 and 31.08–34.41% lower, respectively, than those of Yuyan5 under Cd stress. Cd exposure promoted DOM accumulation in the rhizosphere soils of the two tobacco lines. DOM concentrations in the rhizosphere soils of RG11 were 8.29–14.31% lower than those of Yuyan5 under Cd stress. RG11 presented less hydrophilic acid and hydrophilic base fractions, along with more hydrophobic acid and hydrophobic base fractions of DOM in the rhizosphere than those of Yuyan5 under Cd exposure. Fourier transform infrared spectroscopy results showed that RG11 exhibited less O–H, C–H, C=C, COO–, and C–O functional groups in rhizosphere DOM than those of Yuyan5 under Cd stress. Thus, the DOM in the rhizosphere of RG11 showed lower ability to solubilize Cd in soils, resulting in less Cd uptake by roots. This could be considered to be one of the important mechanisms of low Cd accumulation in leaves of RG11.
Show more [+] Less [-]Long-term cadmium exposure affects cell adhesion and expression of cadherin in the male genital organ of Pardosa pseudoannulata (Bösenberg & Strand, 1906) Full text
2020
Lv, Bo | Wang, Juan | Peng, Yuande | Wang, Zhi | Song, Qisheng
Pardosa pseudoannulata (Araneae: Lycosidae), as an important predator of crop pests, has served as a strong driver for ecological regulation of pests. Cadmium (Cd) is a toxic heavy metal widely distributed in the soil in China, which not only seriously pollutes the ecological environment, but also poses a great threat to the survival of organisms. Palpal bulbs are the genital organs of male spiders, playing an important role in reproductive physiology. However, the effects of long-term Cd stress on the genital organ of the primary pest predator were poorly understood. Therefore, we investigated the Cd effect on the male palpal organ of P. pseudoannulata at morphological and gene expression levels. The results showed that no obvious difference in the morphology between the Cd-treated and control groups was observed, but cell adhesion was affected at molecular level. Transcriptome sequencing analysis revealed that under long-term Cd stress, the biological processes including cell-cell adhesion via plasma-membrane adhesion molecules, cell-cell adhesion, and homophilic cell adhesion via plasma membrane adhesion molecules were the top three differentially expressed terms (p-adj < 0.001), and 51 unigenes were annotated into cadherin-related proteins, such as protocadherin, cadherin-87A, and cadherin-96Ca, among which, 18 unigenes were significantly upregulated under the Cd stress. Our outcomes indicate that the differentially expressed genes involved in cell adhesion may explain the negative effects of Cd stress on the spider genital organ, and the comprehensive transcriptome dataset will also provide a profound molecular information of the genital organ of P. pseudoannulata.
Show more [+] Less [-]Modeling the nexus between pollutant emission, energy consumption, foreign direct investment, and economic growth: new insights from China Full text
2020
Udemba, Edmund Ntom | Magazzino, Cosimo | Bekun, Festus Victor
Most nations are predominately preoccupied with the need to increase economic growth amidst pressure for increased energy consumption. However, higher energy consumption from fossil fuel has its environmental implication(s) especially in a high industrial economy like China. In this context, the current study explores the interaction between pollutant emission, foreign direct investment, energy consumption, tourism arrival, and economic growth for quarterly frequency data from 1995Q1 to 2016Q4 for econometrics analysis. Pesaran’s autoregressive distributed lag–bound test traces long-run relationship between all outlined variables over the investigated period. Empirical results show positive relationship between pollutant emissions with all other variables with the exception of economic growth. This further exposes the environmental degradation in China with the curtailing strength from the GDP. The Granger causality analysis detects that CO₂ emissions and energy consumption show a two-way causality observed. Also, one-way causality existing between growth and foreign direct investment is seen running to pollutant emission. Furthermore, one-way causality is observed among foreign direct investment, energy consumption, pollutant emission, and tourism arrivals with economic growth, and this established their impact on the economic growth which will be a guide to the policy implication on how to ameliorate environmental degradation from the effect of consumption of fossil energy sources and foreign direct investment–induced pollutant emission.
Show more [+] Less [-]Concentration of trace metals in winter wheat and spring barley as a result of digestate, cattle slurry, and mineral fertilizer application Full text
2020
Barłóg, Przemysław | Hlisnikovský, Lukáš | Kunzová, Eva
Concentration of trace metals (TMs) is one of the most crucial factors determining the quality of cereal grains. The aim of this study was to evaluate the effect of digestate, manure, and NPK fertilization on TM concentration in grains and straw of two cereal crops—winter wheat (WW) and spring barley (SB)—and TM transfer from soil to plants. The experiment was carried out between 2012 and 2016. Every year, the same treatment was used on each plot: control (without fertilization), digestate, digestate + straw, cattle slurry, and mineral NPK fertilization. In general, fertilization increased the concentration of TMs that belong to the micronutrient group (Zn, Cu, Fe), particularly after application of digestate and cattle slurry. At the same time, fertilization, regardless of the fertilizer type, led to an increase in Cd concentration in the grain of WW in comparison with the control. Despite the increase in Cd and micronutrient content as a result of fertilization, the concentration of elements remained below the applicable standards. Among TMs, only Pb content exceeded the European Union limits. The increased concentration of Pb was, however, an effect of other factors, rather than fertilization. The results clearly indicated that the biogas digestate from anaerobic codigestion of cattle slurry and agricultural residue could be utilized as fertilizer in agricultural applications without a risk of contaminating the food chain with TMs.
Show more [+] Less [-]West Africa’s CO2 emissions: investigating the economic indicators, forecasting, and proposing pathways to reduce carbon emission levels Full text
2020
Ameyaw, Bismark | Li, Yao | Annan, Augustine | Agyeman, Joy Korang
This paper investigates the nexus between carbon emissions (CO₂) and economic growth in West Africa based on the Environment Kuznets Curve (EKC) hypothesis by utilizing spatial panel data technique to check the possible effect of spatial dependence among countries in West Africa. Our empirical findings suggest the presence of spatial dependence of carbon emissions distribution in West Africa. By examining the existence of EKC embedded within the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) approach, we conclude an inverse N-trajectory of the relationship between carbon emissions and economic growth. Furthermore, to mitigate global carbon emissions, we utilize a recurrent neural network (RNN) bidirectional long short-term memory (BiLSTM) algorithm devoid of exogenous variables and assumptions to forecast carbon emissions from the year 2015 to the year 2030 based on the predictive accuracy of our formulated algorithm. Due to the upward trends in future emission levels, we propose emissions mitigation pathways for countries in West Africa to still hold carbon emissions-related global warming well below 1.5 and 2 °C. Such mitigation pathways proposed could help implement strategic policies to minimize carbon emissions to a considerable level. As a policy implication, drafting strict environmental regulations and utilizing renewable energy technologies will help mitigate carbon emissions for all West African countries.
Show more [+] Less [-]Highly effective adsorption removal of perfluorooctanoic acid (PFOA) from aqueous solution using calcined layer-like Mg-Al hydrotalcites nanosheets Full text
2020
Yang, Yiqiong | Yang, Minhui | Zheng, Zenghui | Zhang, Xiaodong
To study the influence factors of calcined layer-like Mg-Al hydrotalcites nanosheets adsorbing perfluorooctanoic acid (PFOA) in aqueous solution, Mg-Al hydrotalcite (HMA) nanosheets were prepared by one-step hydrothermal synthesis. The effect of calcination temperature on adsorption properties and structure of HMA (CHMA-x, x means different calcination temperature) was investigated. The prepared samples were systematically characterized by the Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and nitrogen adsorption-desorption isotherms. The adsorption isotherms and kinetics showed the adsorption equilibrium reached within 2 h, and the factors, such as adsorption dosage, pH, and cycles were investigated. It was found that CHMA with 600 °C displayed a uniformly morphology, higher surface area about 106.3 m²/g, and excellent adsorption properties (1969 mg/g). The equilibrium adsorption data perfectly fitted to the pseudo-second-order kinetic model (R² = 0.999) and the Freundlich model (R² = 0.994). The main mechanism of CHMA adsorbing PFOA might be the “memory effect.” This study provided a new insight to prepare highly effective adsorbents in water treatment.
Show more [+] Less [-]Assessment of seasonal and spatial variations of biochemical markers in Corydalus sp. (Megaloptera: Corydalidae), a non-conventional biomonitor, in a mountain cloud forest in Mexico Full text
2020
Rico-Sánchez, Axel Eduardo | Rodríguez-Romero, Alexis Joseph | Sedeño Díaz, Jacinto Elías | López López, Eugenia
Rivers are critical ecosystems for protecting and harboring high biodiversity. Tropical rivers particularly are unique for facing extreme climatic events under the current accelerated disruption from human activities. The Bobos-Nautla river basin is exposed to climatic events and disturbances from anthropogenic impacts that stress aquatic organisms. We assessed the health condition of this river system using a non-conventional biomonitor, Corydalus sp., with a set of early-warning biomarkers including lipid peroxidation levels (LPO) and antioxidant activity, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and the neurotransmitter acetylcholinesterase (AChE) considering their spatial and temporal variations. Biomarkers and water quality parameters were analyzed, and the integrated biomarker response (IBR) was assessed as a stress index. Biomarkers showed no significant spatial differences; however, a high-stress period during the rainy season was detected, evidenced by the highest LPO levels; this period is related to the leaching of allochthonous materials from agricultural and urban zones. The peak IBR value during the rainy season confirmed the seasonality of biomarkers. A slight increase in IBR was recorded in lowlands, seemingly associated with agricultural land and human settlements. A principal component analysis showed nutrient enrichment during the rainy season and depletion during the cold-dry season, together with a peak activity of antioxidant enzymes. These results highlight the importance of climatic events such as the rainy season on the health condition of Corydalus sp., which is highly sensitive to the complex mixtures of pollutants that enter the waterbody during extreme climatic events, promoting oxidative stress. Our results also showed the ability of Corydalus sp. to recover and return to a basal level.
Show more [+] Less [-]The relation of structure and metal-support interaction with three-way catalytic performance of Rh/(Ce,Zr,La)O2 catalysts Full text
2020
Wang, Ting | Li, Yan | Zhou, Ren-xian
(Ce,Zr,La)O₂ (CZL) mixed oxide-supported rhodium (Rh) catalysts were prepared by in situ synthesis method. Characterizations were adopted to investigate the relation of structure and metal-support interaction with catalytic behavior of catalysts. The results demonstrate that appropriate Ce/Zr ratio (2/1~1/4) could help to form more homogenous CZL ternary solid solution and promote the formation of more oxygen vacancies and defects (the lattice defects resulting from lattice distortion) in CZL supports, and thereby enhance oxygen storage/release performance. Meanwhile, it strongly affects the interaction between RhOₓ and CZL supports, which promotes the formation of more active Rh species (Rh⁰ + Rh³⁺) and the reduction of the oxygen species in Rh–Ce interface, leading to the enhancement of catalytic performance for HC, CO, and NOₓ eliminations. Rh/CZL-12 shows the best catalytic activity for HC and NOₓ eliminations. It could be attributed to the enhanced activation and oxygen mobility of lattice oxygen, which is verified by the results of DOSC measurement.
Show more [+] Less [-]Cross-Strait climate change and agricultural product loss Full text
2020
Lin, Hsing-Chun | Chou, Li-Chen | Zhang, Wan-Hao
The structure of agricultural industries at Cross-Strait differs as climate change is considered. In fact, its influence on their agriculture and other industries vary when the impact produced by natural disasters due to climate change are faced. To estimate direct and indirect losses caused by natural disasters, this study applies Inter-Country Input-Output (ICIO) analysis developed by Miller and Blair (2009) to discuss the development among Cross-Strait industries as they face disaster losses. The data sources used in this article are from Lin (2013), Cross-Strait ICIO table, and the statistics of agriculture in the periods 2005–2017 for Taiwan and Mainland China. The main results from our ICIO analysis are as follows: the value-added losses caused by natural disasters mainly involve agriculture, forestry, fishery, wholesale and retail trade, animal feed, and chemical fertilizer industries. These sectors account for 87.4% in Mainland China and 94.6% in Taiwan of total separately.
Show more [+] Less [-]Interactions between dietary habits and home environmental exposures on respiratory symptoms in Romanian school children: an analysis of data from the SINPHONIE project Full text
2020
Lawrence, Wayne R. | Lin, Shao | Lin, Ziqiang | Gurram, Namratha | Neamtiu, Iulia A. | Csobod, Eva | Gurzau, Eugen
In this study, we investigated the interactions between household pollutants and dietary habits on children’s respiratory health. Our cross-sectional study collected self-reported information including health symptoms (allergy-like, asthma-like, and flu-like symptoms), home characteristics, dietary habits, and demographic information from questionnaires administered to parents of 280 school children in Romania. Unconditional logistic regression and stratified analyses were used to assess the interactions between dietary factors and environmental exposures on health symptoms among children, controlling for sociodemographic characteristics and co-exposures. We found that frequency of fruit consumption had significant interaction with residing near heavy traffic on allergy-like symptoms among children (p = 0.036). However, no association was observed by frequency of fruit consumption. Although no significant interaction was observed, we found that students with infrequent fruit consumption and residing near heavy traffic roads had elevated odds of asthma-like (POR 6.37; 95% CI 1.22, 33.29) and flu-like symptoms (POR 3.75; 95% CI 1.12, 11.86) than those who frequently consumed fruits. Likewise, low vegetable consumption was associated with increased asthma-like symptoms (POR 2.93; 95% CI 1.04, 8.24). Increased odds of asthma-like symptoms were observed among school children that resided near heavy traffic roads and frequently consumed milk (POR 2.80; 95% CI 1.24, 6.31) and yoghurt (POR 2.86; 95% CI 1.05, 7.75) compared to those that infrequently consumed dairy. Our findings suggest that frequent fruit and vegetable consumption may mitigate the negative effects of exposure to heavy traffic near dwelling on respiratory symptoms in Romanian children.
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