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11.
The recent development of new generation Low-Pressure Reverse Osmosis (LPRO) or nanofiltration membranes have received attraction for application in the field of wastewater and water treatment through an increasingly stringent regulation for drinking purpose and water reclamation. In this research, the application on treatment of anionic pollutants (NO3 -, NO2 -, Cl-, SO4 2- &; H2PO4 -) was done under very much lower pressure range of operation (0.49 to less than 0.1 MPa) than any other previous research has done. Moreover, the extended Nernst-Planck equation was used for analysis of the experimental data by considering effective charge density of the membranes.  相似文献   
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ABSTRACT: Evapotranspiration (ET) from oasis and Gobi surfaces in the Heihe River region of China was estimated by Kotoda (1986) and Advection-Aridity (Brutsaert and Stricker, 1979) models. The ET estimates were compared with eddy-correlation ET estimates. The ET estimated by both models are in good agreement with ET obtained by means of eddy-correlation method for the oasis surface while underestimating ET as compared to the eddy-correlation method. For the Gobi surface, the models yielded obviously overestimates of evapotranspiration. In order to estimate evapotranspiration from arid surfaces, the Kotoda model was modified by introducing the surface moisture availability parameter a from Barton (1979). The modified Kotoda model yielded ET estimates that were very close to that from the eddy-correlation method for the Gobi surface. The modified Kotoda model was used to estimate evapotranspiration from the Heihe River watershed, an area with complicated topography and land use, and the results compared with those from a water balance method. A sensitivity analysis of the modified model was performed. The results show that the modified Kotoda model can reflect the relationship between the actual evapotranspiration and the main controlling factors on it for both wet and arid surfaces reasonably. From this study, it can be concluded that the modified Kotoda model is applicable fro the estimation of regional evapotranspiration from areas with complicated topography and land use.  相似文献   
14.
The efficiencies of neutral salts, strong acids, and chelates were tested for extracting cadmium (Cd) from three paddy soils. The higher the selectivity of the cations of the added neutral salts toward soil adsorption sites, the lower the pH in the extracts and the more soil Cd could be extracted. In addition, soil carbon and nitrogen contents and mineral composition were closely associated with the amount of Cd extracted. Calcium chloride and iron(III) chloride were selected as wash chemicals to restore Cd-contaminated paddy soils in situ. Washing with calcium chloride led to the formation of Cd chloride complexes, enhancing Cd extraction from the soils. The washing also substantially decreased soil levels of exchangeable and acid-soluble Cd, which are the major forms of bioavailable Cd for rice (Oryza sativa L.). The optimum conditions for in situ soil washing were also determined for calcium chloride.  相似文献   
15.
The synthesis of recycled plastics from recovered monomeric materials obtained from the depolymerization reaction of fiber-reinforced plastics (FRP) was examined. The depolymerization reaction of FRP in the presence of N,N-dimethylaminopyridine (DMAP) smoothly yielded the corresponding monomers, which mainly consisted of dimethyl phthalates. The polymerization reaction with this monomer failed to form the corresponding unsaturated polyesters due to contamination by N-methyl-4-pyridone, a decomposition product of DMAP. An efficient purification of the recovered monomer was achieved by washing with water, and the purified monomer successfully yielded the corresponding polymers. A hardness test revealed that the polymers were as hard as the polyester made from virgin materials. The present modification provides a practical method for the preparation of recycled plastics from depolymerized plastics.  相似文献   
16.
The Tsurumi, a class-one Japanese river, has a significant metal loading originating from urban environment. Water and sediment samples were collected from 20 sites in winter and summer, 2009 and were analyzed to determine and compare the extent of different trace element enrichment. A widely used five-step sequential extraction procedure was also employed for the fractionation of the trace elements. Concentrations of zinc, copper, lead, chromium, and cadmium were three to four times higher than that of reference values and downstream sediments are much more polluted than the upstream sites. Geochemical partitioning results suggest that the potential trace metal mobility in aquatic environment was in the order of: cadmium > zinc > lead > copper > cobalt > chromium > molybdenum > nickel. About 80.2% zinc, 77.9% molybdenum, 75.3% cobalt, 63.7% lead, 60.9% copper, 55.1% chromium, and 39.8% nickel in the sediment were contributed anthropogenically. According to intensity of pollution, Tsurumi river sediments are moderately to heavily contaminated by zinc, lead, and cobalt. Enrichment factor values demonstrated that zinc, lead, and molybdenum have minor enrichment in both the season. The pollution load index (PLI) has been used to access the pollution load of different sampling sites. The area load index and average PLI values of the river were 7.77 and 4.93 in winter and 7.72 and 4.89 in summer, respectively. If the magnitude of pollution with trace metal in the river system increases continuously, it may have a severe impact on the river’s aquatic ecology.  相似文献   
17.
There is a strong need for the development of relatively rapid and low-cost bioassays for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in environmental and food samples. In this study, we applied a reporter gene assay using DR-EcoScreen cells (DR-cell assay), which is highly sensitive to dioxins, to the determination of PCDD/Fs and dl-PCBs in fish and seafood samples. The PCDD/Fs and dl-PCBs were extracted from homogenated samples (10 g) of 30 fish and shellfish, purified by clean-up procedure using a multilayered silica gel column and an alumina column, and applied to DR-cell assay. Interestingly, the bioanalytical equivalent (BEQ) values obtained from the DR-cell assay [<0.1 ∼ 5.4 pg BEQ g−1 wet weight (ww)] were closely correlated with the toxicity equivalent (TEQ) values from conventional high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) analysis (r2 = 0.912), and the slope of regression line was 0.913. Therefore, we multiplied the BEQ values from the DR-cell assay by a conversion coefficient (1.095, the reciprocal of 0.913) to approximate the TEQ values from the HRGC-HRMS analysis. Furthermore, we used this DR-cell assay to perform a prescreening test of PCDD/Fs and dl-PCBs in 16 fish and seafood samples purchased from a supermarket, revealing that a sample from the fatty flesh of a bluefin tuna exceeded 8 pg TEQ g−1 ww (the European Union-tolerance limit). Taken together, these results suggest that the DR-cell assay might be applicable as a rapid and low-cost prescreening method to determine dioxin levels in fish and seafood samples.  相似文献   
18.
Several recent hypotheses on the adaptive significance of autumn leaf colours have focused on specialist aphids. However, these hypotheses have overlooked several factors: the preferential investment by healthy vigorous trees in growth rather than defence against herbivores, variation among aphid species in their responses to bright autumn leaves and plant defences and the occurrence of tritrophic interactions in tree crowns. I incorporate these factors into a hypothesis that autumn leaf colours signal tree quality to myrmecophilous specialist aphids, with the aphids, in turn, attracting aphid-tending ants during the following spring, and the ants defending the trees from other aphids and herbivores. Therefore, bright autumn leaves may have adaptive significance, attracting myrmecophilous specialist aphids and their attending ants and, thus, reducing herbivory and competition among aphids.  相似文献   
19.
The evergreen oak Quercus gilva Blume sheds leaves containing mines of the leaf miner Stigmella sp. (Lepidoptera: Nepticulidae) earlier than leaves with no mines in early spring in Nara, central Japan. The eclosion rates of the leaf miner in abscised and retained leaves were compared in the laboratory to clarify the effects of leaf abscission on leaf miner survival in the absence of deer. The leaf miner eclosed successfully from both fallen leaves and leaves retained on trees. However, sika deer (Cervus nippon centralis Kishida) feed on the fallen mined leaves. Field observations showed that deer consume many fallen leaves under Q. gilva trees, suggesting considerable mortality of leaf miners due to deer predation via leaf abscission. This is a previously unreported relationship between a leaf miner and a mammalian herbivore via leaf abscission.  相似文献   
20.
Fatty acid synthase (FAS) had been found overexpress and hyperactive in most cancers. Pharmacological inhibitors of FAS activity preferentially repress cancer cell proliferation and induce cancer cell apoptosis without affecting nonmalignant fibroblasts. These made FAS an excellent drug target for cancer therapy. The activity of FAS in 11 different kinds of cancer cells, including esophageal carcinoma (EC109, EC8712, H5E973), gastric carcinoma (N87, BGC823), lung carcinoma (A549, 95-D), hepatoma (HepG2), uterine cervix cancer (HeLa) and leukaemia (K562, U937) were compared using spectrophotometric method. We selected the cell line with the highest FAS activity as cell model to study the inhibitory effect of the flavonoids extracts on FAS. Four plants including Canavium album Raeuseh leaves, Bombax ceiba Linn, Brassica albograbra Bailey, and Citrus reticulata Blanco were selected for extracting flavonoids. The results showed significantly different FAS activity among different cancer cells. The FAS activity is the lowest in gastric cancer cell N87 (15.91 ± 3.61 U/mg protein) and the highest in lung cancer cell A549 (127.36 ± 10.14 U/mg protein). The cancer cell A549 was used as cell model to test the inhibitory effort of flavonoids extracts on FAS. Results showed that the flavonoids extracts of Citrus reticulata Blanco and Canavium album Raeuseh leaves have higher inhibitory effect on FAS activity compared with the universally used FAS inhibitor C75 and both extracts inhibit cancer cell proliferation when added to cultured cancer cells. These studies provided a good cell model for testing the inhibitory effect on FAS activity and suggested that Citrus reticulata Blanco rind and Canavium album Raeuseh leaves are good biomaterials for separating and purifying natural flavonoids FAS inhibitors and exploring their inhibitory mechanisms.  相似文献   
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