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The main aim of this study was to describe the adsorption behaviours of acetaminophen (APAP) onto colloid and solid particle in sediment in terms of their impact on the factors of the processes (e.g., contact time, temperature, kinetic, thermodynamic characteristics) that were analyzed systematically. Sediment was collected from a typical tributary in the mid-Weihe River and a separation device was employed to separate sediment into colloid and solid particle. Results show that the adsorption of APAP onto colloid and solid particle reached equilibrium after about 12 hours and 48 hours, respectively. The adsorption capacity of APAP onto colloid was at least 28-fold larger than that onto solid particle with an initial APAP concentration of 10.0 mg·L⁻¹ at 25ºC. The Langmuir isotherm model was more suitable for describing the adsorption behaviours of APAP onto both colloid and solid particle in sediment. The adsorption processes were feasible, spontaneous, entropyincreasing, and endothermic in nature, the adsorption capacity increased with increasing temperature. The mechanisms controlling APAP adsorption onto colloid and solid particle were mainly physisorption, but physisorption less on APAP adsorption onto colloid. The obtained results provide a theoretical basis for the effective prevention of APAP pollution to the groundwater system in the Weihe River basin.
Apple scar skin viroid (ASSVd) is a serious pathogen of apple fruits that results in severe loss in apple production. Up to nowadays, many ASSVd management options are applied to resist the disease, but the diserable resulits are not achieved. Therefore, this study was conducted in 2010–2012 at experimental field of Penglai City, Shandong Province, China (E 120°57’22’’, N 370°38’33’’) to investigate whether arbuscular mycorrhizal (AM) Glomus versiforme protects Red Fuji apple trees (Malus × domestica Borkh) against apple scar skin viroid. Red Fuji apple trees were inoculated with Glomus versiforme and then potential protection mechanism was explored and compared to noninoculated plants. The results showed that inoculation with Glomus versiforme significantly increased root length colonization rate and clearly decreased the percentage of disease severity of apple scar skin disease. Compared to non-inoculated plants, Glomus versiforme obviously enhanced total nitrogen and phosphorus concentrations in leaves. Root colonization by Glomus versiforme induced an increase in defense-related enzyme activities in fruits, such as the enhanced activities of catalase, ascorbate peroxidase, chitinase and glucanase. Significant differences in acid content of fruit and fruit yield were observed as apple roots were colonized by Glomus versiforme. It is therefore concluded that Glomus versiforme can be regarded as a biocontrol agent to protect apple trees against the infection with ASSVd.
To reveal the impact of vertical non-uniform distribution of soil moisture on nitrous oxide (N2O) emissions, incubated experiments were conducted from April to August 2013 on silty clay and sandy loam with four watering regimes [surface watering (SW) and subsurface watering application to levels 12, 15, and 18 cm below soil surface (SUW12, SUW15, SUW18)]. Short-term pulse emissions of N2O from both soils during the drying process were observed. The soil water-filled pore space (WFPS) at 0-12 cm depths for peak N2O fluxes in SW and SUW soils fell within 34-66%, 22-72%, 25-35%, and 19-39% for silty clay and sandy loam, respectively. Our results also suggest that the N2O fluxes from soil of sily clay with higher N content are much higher than that from sandy loam, and N2O were more easily influenced by soil moisture in SW soils than in SUW soils. However, more research is needed to identify an ideal soil-wetting pattern and the way to realize the ideal soil-wetting pattern, especially on soil with plant growth and fertilization.
The dredger fill of Shanghai Hengsha Island Dongtan is solidified by curing agents with different fly ash content, and the shear strength index of solidified dredger fill is measured by the direct shear test. The microscopic images of solidified dredger fill are obtained by using SEM. The microscopic images are processed and analyzed by using IPP, and the fractal dimension including particle size fractal dimension Dps, aperture fractal dimension Dbs and particle surface fractal dimension Dpr is calculated by fractal theory. The quantitative analysis of the relationship between shear strength index and fractal dimension of solidified dredger fill is done. The research results show that the internal friction angle and the cohesion are closely related to the fly ash content λ and the curing period T, and the addition of fly ash can improve the effect of curing agent; There is no obvious linear relationship between the internal friction angle and the three fractal dimensions; The smaller particle surface fractal dimension Dpr and particle size fractal dimension Dps, the larger aperture fractal dimension Dbs, the greater the cohesion, and the cohesion has a good linear relationship with three fractal dimensions, and the correlation coefficient R2 is above 0.91
To reveal the impact of irrigation management on the release and leaching of soil metals (Cu, Zn, Pb, Cr, and Cd), deep percolation rate and metals contents in soil solutions were observed in rice fields with nonflooding controlled irrigation (NFI) and flooding irrigation (FI) treatments. The contents of Cu and Cr in the deep solutions were safe according to the environmental quality standard for groundwater, but contents of other metals might lead to groundwater contamination, especially for Cd. The release of metals in surface soil was increased for NFI because the wetting-drying cycles in NFI fields resulted in less reluctant and high decomposition and mineralization of soil organic matter in surface soil, and consequently enhanced the release of soil metals into solutions. Seasonal metals leaching losses in NFI fields were 44.9-53.8% lower than in FI, due to the large reduction in both deep seepage rates and metals concentrations in deep soil solutions. Higher release of metals in NFI surface soils might lead to higher bioavailability of micronutrients (Cu and Zn) to crops, but higher risks in toxic metals (Pb, Cr, and Cd) uptakes.
Pollution and control on highway surface runoff have become a serious problem in highway environmental protection. Constructing a highway in a water conservation district could bring benefi ts as well as a variety of environmental pollution and potential damage. Based on water conservation district sensitivity and highway runoff characteristics, the current paper analyzes the impact of highway runoff on water quality in the water source protection area. It hasn’t yet had a good and mature process with respect to the drainage of the drinking water source reserves of domestic highways. It was designed as a concentrated drainage treatment system to process the drainage of sensitive sections as outlined in this paper. Highway surface runoff characteristics were studied by monitoring, investigating, sampling, and analyzing the Renhuai-to- Chishui highway (RCH), and then the concentrated drainage treatment system was designed, and the water is collected piecewise along the route. The processing system can not only effectively deal with road surface runoff of the water source protection area, but also to cope with risk. Combined with the actual situation of water source conservation areas around RCH, we have carried out a detailed demonstration of the drainage system in order to mollify the contradiction between the water resource protection area and development of traffi c in the water reserves. The results showed that the processing rates – as high as 83.17-93.77% – and the concentrated drainage treatment system could guarantee effl uents meeting discharge standards. This study demonstrates the effectiveness of the concentrated drainage treatment system in RCH and establishes an advanced technology for highway surface runoff control.
To exam ine the residues and distributions of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane (DDT), and other organochlorine pesticides (OCPs ) in the Weihe River basin of northwest China, a gas chromatography-mass spectrometer (GC-MS) was employed to analyze the samples collected from surface water, suspended solids, and sediments. Results showed that total concentrations of HCHs, DDT, and othe r OCPs in surface water were in the range of 2.41-178.18, 0.94-116.83, and 3.64-37.17 ng/L, respectiv ely; in suspended solids they were 5 1.76-241.23, 2.82-12.23, and 11.35-37.67 ng/L, respectively; and in sediments they were 74.13-517.49, 1.20-370.98, and 7.94-110.13 ng/g dry weight, respectively. The α-HCH/γ-HCH ratio indicated that historical usage of technical mixtures of HCHs was the main source of HCHs. The DDT ratio indicated that DDT at most sites came from older uses of technical DDT. Compared with some guideline values of OCPs in surface water, the concentrations of HCHs and DDT were at safe levels. Meanwhile, the Weihe Riv er sediments have high ecological risk pesticides.
Older apple trees often demonstrate physiologically unreasonable shoot distribution due to root system aging, which results in lower fruit yield and poor fruit quality. Therefore this study was conducted to test whether root pruning combined with arbuscular mycorrhizal fungi could restore growth potential of fortyyear-old Red Fuji apple trees (Malus × domestica Borkh.) in a commercial orchard in 2013, by root pruning along both sides of rows, 80 cm from the trunk, to a depth of 30 cm and application of 100 ml arbuscular mycorrhizal inoculum per plant. Results showed that the percentage of root colonized by mycorrhizal fungi increased as root pruning was combined with arbuscular mycorrhizal fungi, however mycorrhizal colonization was not seen in the control roots and roots only by root pruning. For control tree total number of shoots decreased by 28.22% in 2015 than in 2013 and shoots mainly distributed in the outer canopy accounting for 58.10% of the total, which caused the lower light intensity inside the canopy, followed by lower fruit yield and poor fruit quality. Compared to control plant, shoot reduced by 33.96 and 38.51% in the outer canopy but increased by 97.99 and 123.69% in the inner canopy in 2015, as well as 390.20 and 478.43% in the vertical height of 1.5 to 2.5 m canopy, respectively treated by root pruning alone and combined with arbuscular mycorrhizal fungi. Root pruning alone and combined with arbuscular mycorrhizal fungi also raised the relative light intensity by 38.71 and 60.26% in the inner canopy in 2015, subsequent fruit yield by 315.79 and 373.68% respectively, in comparison to control plant. Shoot re-distribution improved fruit quality such as increase in firmness and soluble solid. Data indicated that the effect of root pruning combined with arbuscular mycorrhizal fungi on the rejuvenation of older apple trees was stronger than root pruning alone. It is therefore concluded that root pruning combined with arbuscular mycorrhizal fungi can think of as a measure to renew the older apple trees.
In our work a two-stage A/O system consisting of two independent A/O subsystems was used to remove high concentrations of COD, nitrogen, and toxic matter from mixed wastewater discharged by a comprehensive chemical group. The mixed liquid return was not adopted, and the sludge return ratio was kept at a high value of 100-200% to maintain high usable activated sludge concentration. Adequate NaHCO₃ was added to keep the influent alkalinity/KN ratio around 7.14 to 1. The system was running stably during the whole experimental period. Subsystem one obtained high COD and organic nitrogen removal capability without being influenced by the increasing COD loading. 87.6% COD was removed and 75.7% org-N was transformed to NH₄⁺-N. Due to the low COD/KN ratio created by subsystem one, the nitrification efficiency of subsystem two reached a high value of 92.1%. Besides, aerobic biological oxidation of oxic tank one showed excellent ability on toxic matter elimination. The acute toxicity of the whole system dropped from 0.165 to 0.042 mg HgCl₂/L. It has been proven by this study that, using the two-stage A/O system with sludge return only to treat COD nitrogen and toxic matters, laden mixed wastewater from comprehensive chemical groups may be feasible.
The system of dynamic leaching was designed for samples of a coal gasification residual from a coalto-methanol plant in northwestern China in order to investigate the leaching behavior of four potentially hazardous elements – Hg, Cr, As, and Pb – in the coal gasification residual and investigate the impacts of the leaching time, size of the samples, and pH of the leaching solution on the leaching behavior of elements. The concentrations of elements in the leachate samples were all determined by inductively coupled plasma-mass atomic spectrometry (ICP-MS). The results showed that the leaching time, size of the samples, and pH of the leaching solution played an important role in affecting the leaching behavior of the selected elements from the coal residual samples. All trends were in decreasing order of significance as the leaching time went on and most leached concentrations reached the maximum at the initial stage of leaching experiments (from hours 0 to 4) accounting for 94.44%. The 80-mesh sample had the different leaching curve from the 10-mesh and 40-mesh samples for the same element because different forms of the heavy metals existed on the different-size samples.
Sucrose non-fermenting1-related protein kinase 2 (SnRK2) plays a key role in abiotic stress signaling in plants. In this study, gene structures, phylogeny, conserved motifs and promoters of NtSnRK2.7 and NtSnRK2.8 in tobacco have been analyzed. Phylogenetic analysis showed that NtSnRK2.7 and NtSnRK2.8 belong to subclass I and subclass III of SnRK2, respectively. They exhibited similar genomic structures, consisting of 9 exons and 8 introns. Subcellular localization showed the presence of NtSnRK2s in the cell membrane, cytoplasm and nucleus. Quantitative real-time PCR was used to analyze the expression patterns of NtSnRK2s in tobacco. NtSnRK2s were constitutively expressed strongly in roots, weakly in stems, and marginally in leaves. Abiotic stress response analyses revealed that NtSnRK2.7 and NtSnRK2.8 were involved in response to various abiotic stresses with different patterns: there was evidence that NtSnRK2.7 participated in abscisic acid-independent signaling pathways, while the transcription of NtSnRK2.8 was induced by abscisic acid treatment; NtSnRK2.7 responded much faster to salt and cold stress. Furthermore, expression of NtSnRK2.8 increased intensely and reached its maximum at 1 h under drought stress indicating that it is sensitive to osmotic stress. Our results suggest that NtSnRK2.7 and NtSnRK2.8 are involved in multiple stress response pathways in distinct ways.
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