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121.
Environmental Science and Pollution Research - In recent years, the occurrence of floods is one of the most important challenges facing in Hamadan city. In the absence/inefficiency of urban...  相似文献   
122.
Environmental Science and Pollution Research - The purpose of this study is to evaluate the capability of Secale montanum trusted for phytoremediation of contaminated soils with lead (Pb) and...  相似文献   
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A new series of 3-phenoxyazetidin-2-ones (β-lactams) were designed and synthesized for the evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. In this study, the effects of a synthetic of β-lactam-structured COX-2 inhibitor with 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one on cell viability of cancerous lymphoblast isolated from patients diagnosed with acute lymphocytic leukemia (ALL) and normal lymphocytes collected from healthy donors were investigated. The viability % of cancer lymphoblast and normal lymphocyte treated 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one were tested with MTT assay. Apoptosis and necrosis were measured by double stains of annexin V and propidium iodide, and caspase-3 as a final mediator in apoptotic death measured by colorimetric assay. Mitochondria were isolated from both cancerous lymphoblast and normal lymphocytes to measure parameters of mitochondrial damage such as reactive oxygen species (ROS) formation, mitochondrial membrane potential decrease, swelling, and cytochrome c release following the administration of azithidine-2-one derivative, 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one. Our results showed that 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one inhibited proliferation of cancerous lymphoblast in a concentration-dependent manner by inducing apoptosis but not in normal lymphocytes. Treatment with azithidine-2-one derivative produced a rapid loss of mitochondrial transmembrane potential, stimulation of release of ROS and mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 processing. Data suggest that 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one-induced ROS production led to mitochondria-mediated death signaling that resulted in apoptosis in cancerous lymphoblast cells. The induction of apoptosis by azithidine-2-one compounds, such as 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one, may provide a mechanism for its cancer chemopreventive action in acute lymphocytic leukemia cells.  相似文献   
126.
A novel hydrometallurgical process was proposed for selective recovery of Cu, Ag, Au and Pd from waste printed circuit boards (PCBs). More than 99% of copper content was dissolved by using two consecutive sulfuric acid leaching steps in the presence of H2O2 as oxidizing agents. The solid residue of 2nd leaching step was treated by acidic thiourea in the presence of ferric iron as oxidizing agent and 85.76% Au and 71.36% Ag dissolution was achieved. The precipitation of Au and Ag from acidic thiourea leachate was investigated by using different amounts of sodium borohydride (SBH) as a reducing agent. The leaching of Pd and remained gold from the solid reside of 3rd leaching step was performed in NaClO-HCl-H2O2 leaching system and the effect of different parameters was investigated. The leaching of Pd and specially Au increased by increasing the NaClO concentration up to 10 V% and any further increasing the NaClO concentration has a negligible effect. The leaching of Pd and Au increased by increasing the HCl concentration from 2.5 to 5 M. The leaching of Pd and Au were endothermic and raising the temperature had a positive effect on leaching efficiency. The kinetics of Pd leaching was quite fast and after 30 min complete leaching of Pd was achieved, while the leaching of Au need a longer contact time. The best conditions for leaching of Pd and Au in NaClO-HCl-H2O2 leaching system were determined to be 5 M HCl, 1 V% H2O2, 10 V% NaClO at 336 K for 3 h with a solid/liquid ratio of 1/10. 100% of Pd and Au of what was in the chloride leachate were precipitated by using 2 g/L SBH. Finally, a process flow sheet for the recovery of Cu, Ag, Au and Pd from PCB was proposed.  相似文献   
127.
Carbon dioxide sequestration in deep saline aquifers is a means of reducing anthropogenic atmospheric emissions of CO2. Among various mechanisms, CO2 can be trapped in saline aquifers by dissolution in the formation water. Vaporization of water occurs along with the dissolution of CO2. Vaporization can cause salt precipitation, which reduces porosity and impairs permeability of the reservoir in the vicinity of the wellbore, and can lead to reduction in injectivity. The amount of salt precipitation and the region in which it occurs may be important in CO2 storage operations if salt precipitation significantly reduces injectivity. Here we develop an analytical model, as a simple and efficient tool to predict the amount of salt precipitation over time and space. This model is particularly useful at high injection velocities, when viscous forces dominate.First, we develop a model which treats the vaporization of water and dissolution of CO2 in radial geometry. Next, the model is used to predict salt precipitation. The combined model is then extended to evaluate the effect of salt precipitation on permeability in terms of a time-dependent skin factor. Finally, the analytical model is corroborated by application to a specific problem with an available numerical solution, where a close agreement between the solutions is observed. We use the results to examine the effect of assumptions and approximations made in the development of the analytical solution. For cases studied, salt saturation was a few percent. The loss in injectivity depends on the degree of reduction of formation permeability with increased salt saturation. For permeability-reduction models considered in this work, the loss in injectivity was not severe. However, one limitation of the model is that it neglects capillary and gravity forces, and these forces might increase salt precipitation at the bottom of formation particularly when injection rate is low.  相似文献   
128.
Prediction of the amount of hospital waste production will be helpful in the storage, transportation and disposal of hospital waste management. Based on this fact, two predictor models including artificial neural networks (ANNs) and multiple linear regression (MLR) were applied to predict the rate of medical waste generation totally and in different types of sharp, infectious and general. In this study, a 5-fold cross-validation procedure on a database containing total of 50 hospitals of Fars province (Iran) were used to verify the performance of the models. Three performance measures including MAR, RMSE and R2 were used to evaluate performance of models. The MLR as a conventional model obtained poor prediction performance measure values. However, MLR distinguished hospital capacity and bed occupancy as more significant parameters. On the other hand, ANNs as a more powerful model, which has not been introduced in predicting rate of medical waste generation, showed high performance measure values, especially 0.99 value of R2 confirming the good fit of the data. Such satisfactory results could be attributed to the non-linear nature of ANNs in problem solving which provides the opportunity for relating independent variables to dependent ones non-linearly. In conclusion, the obtained results showed that our ANN-based model approach is very promising and may play a useful role in developing a better cost-effective strategy for waste management in future.  相似文献   
129.
The levels of mercury in tissues of Penaeus merguiensis from Musa estuary, northwest of the Persian Gulf, were investigated. This study assessed the relationship between mercury levels in hepatopancrea, gill, and muscle with sex, size, and season. The order of mercury concentrations in tissues of the shrimp P. merguiensis was as follows: hepatopancreas > gill > muscle. There was a positive correlation between mercury concentrations in shrimp species with sex and size of its food items. We expected to see higher mercury levels in tissues of female species because they are larger and can eat larger food items. Also, there was a positive correlation between mercury concentrations in shrimp species with its food source. Therefore, female species feed more on shrimp and plant and are contaminated with high levels of mercury. There was significant difference (p?<?0.05) in mercury levels between different seasons; higher mercury levels were found in July (summer season).  相似文献   
130.
Because of over-exploitation of sturgeon for caviar production, they have been listed worldwide in annex II of the Convention on International Trade in Endangered Species regulations; so caviar production using aquaculture is increasingly seen as a feasible way to reduce overfishing. The accumulation of the nonessential metals As, Ba, Cd, Hg, Pb, and Sn was determined in the caviar of farmed and wild Beluga sturgeon (Huso huso). The levels of As in both and Cd in wild samples were less than 0.01 mg kg?1 wet weight, and the comparison for all of the metals studied did not show large fluctuations in metal concentrations between farmed and wild caviar samples. The average for each toxic metal was below the permissible limits proposed by the UK’s Ministry of Agriculture, Fisheries and Foods (2000). The maximum allowable daily consumption rate of caviar was calculated; however, the health risks from caviar consumption are uncertain because the amount of caviar consumed by heavy users is not known.  相似文献   
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