Histopathological effects of copper oxide nanoparticles on the gill and intestine of common carp (Cyprinus carpio) in the presence of titanium dioxide nanoparticles

In current research, the combined effects of copper oxide nanoparticles (CuO NPs) and titanium dioxide nanoparticles (TiO₂ NPs) on the histopathological anomalies of gill and intestine tissues in common carp (Cyprinus carpio) were studied. Common carp were exposed to TiO₂ NPs (10.0?mg L^?1), CuO NPs (2.5 and 5.0?mg L^?1), and mixture of TiO₂ NPs (10.0?mg L^?1)?+?CuO NPs (2.5 and 5.0 mg?L^?1) for two periods of exposure (10 and 20 days) and recovery (30 and 40 days). The most common histopathological anomalies in the gill of common carp such as hyperplasia, oedema, curvature, fusion, aneurism, and necrosis were observed. The synergistic effect of co-existing TiO₂ NPs and CuO NPs reduced the length of secondary lamella and increased the diameters of the gill filaments and secondary lamellae. Moreover, the presence of TiO₂ NPs increased the CuO NPs effects on the histopathological anomalies of intestine tissue and the synergistic effect of TiO₂ NPs and CuO mixture leads to an increase in the severity of histopathological lesions such as degeneration, swelling of goblet cells, and necrosis - erosion in the intestine tissue. In conclusion, the presence of TiO₂ NPs increased the toxicity of CuO NPs.     

Radiation heat transfer in transient dust cloud flame propagation

This study investigates the impact of radiation heat transfer and heat conduction on dust cloud combustion. Radiation plays a very important role in the stability of dust cloud flame, and increasing the amount of radiation drastically raises the possibility of instability and explosion in a dust cloud mixture. Flame speed, which is a function of mixture characteristics, can exhibit a fluctuating behavior. By using the discrete heat source method, it would be possible to study the transient propagation of dust flames. Thus, the propagation speed of flame can be obtained, and as time goes by, the transient speed of dust flame will reach its steady state value. By considering the radiation effect, better agreement is observed between the obtained results and experimental data.     

Sample Preparation Followed by High Performance Liquid Chromatographic (HPLC) Analysis for Monitoring Muconic Acid as a Biomarker of Occupational Exposure to Benzene

Factors affecting solid phase extraction (SPE) of trans,trans-muconic acid (ttMA), as a benzene biomarker, including sample pH, sample concentration, sample volume, sample flow rate, washing solvent, elution solvent, and type of sorbent were evaluated. Extracted samples were determined by HPLC-UV(highperformance liquid chromatography-ultraviolet). The analytical column was C18, UV wave length was 259 nm, and the mobile phase was H2O/methanol/acetic acid run at flow rate of 1 ml/min. A strong anion exchange silica cartridge was found successful in simplifying SPE. There was a significant difference between recoveries of ttMA when different factors were used (p < .001). An optimum recovery was obtained when sample pH was adjusted at 7. There was no significant difference when different sample concentrations were used (p > .05). The optimized method was then validated with 3 different pools of samples showing good reproducibility over 6 consecutive days and 6 within-day experiments.     

Exploration and development of Iran's oilfields through buyback

The use of buyback for the development of oil and gas fields is an established mechanism in Iran. Current legislation authorizes the National Iranian Oil Company (NIOC) to use buyback for both exploration and development. The buyback scheme can be defined as a risk service contract, under which the contractor is paid back by being allocated a portion of oil/gas produced as a result of providing services. Buyback is based upon a defined scope of work, a capital cost ceiling, a fixed remuneration fee and a defined cost recovery period. When buyback is used for both exploration and development, the specifications of the field to be developed are unknown at the time of contracting and therefore agreement on the scope of work, duration of development operations, ceiling for capital costs, fixed remuneration fee, and duration of cost recovery need to be deferred to the time when a commercial field is discovered. This article first outlines the introduction of buyback for development of Iran's oil and gas fields. It then examines the main features of the mechanism. Third, the use of buyback for both exploration and development is explored and related challenges discussed. Finally, the article reviews the new buyback model proposed by NIOC to address these challenges.     

Protective effects of quercetin against sodium fluoride-induced oxidative stress in rat erythrocytes

Protective effects of quercetin against oxidative stress induced by sodium fluoride intoxication in rat erythrocytes were evaluated. Rats were divided into five groups consisting of 10 in each for this experiment. The animals of group I received water and standard diet to serve as control group, the animals of groups II and III were treated with quercetin (10 and 20?mg?kg^?1 body weight), administrated intraperitoneally for 7 days followed by sodium fluoride (600?ppm) in drinking water for the next 7 days. The animals of group IV were treated with vitamin C (10?mg?kg^?1) intraperitoneally for 7 days followed by sodium fluoride treatment for next 7 days serving as positive control group. The animals of group V were treated only with sodium fluoride (600?ppm) for the same time and were used as control group. Blood sample were collected via retro-orbital puncture. The antioxidant enzymes, superoxide dismutase, and catalase, as well as the levels of reduced glutathione and lipid peroxidation end products were measured in erythrocytes. There was a significant increase in lipid peroxidation along with a decrease in superoxide dismutase activity in the erythrocytes of sodium fluoride-treated animals. Quercetin treatment prior to fluoride administration normalized the levels of all parameters measured in the rat erythrocytes.     

Bioremediation of toxic metals mercury and cesium using three types of biosorbent: bacterial exopolymer,gall nut,and oak fruit particles

Cesium and mercury are two mono-valent elements which can be found in toxic industrial, medical, and nuclear wastes. Their presence in the environment has deleterious effects on the ecosystem, living organisms including humans. Due to the chemical nature of these metals, bioremediation by conventional methods is more difficult to achieve compared to other metals. In this study, we used three biosorbents (oak powder, gall nut, and bacterial exopolymer) for the bioremediation of Hg and Cs. Bio-polymer was produced in the GMS mineral broth. Synthetic wastes of Hg(NO₃)₂ and isotope Cs-133 as the single-metal solutions were used. The biorefining process was carried out in glass columns, made of Pyrex, with dimensions 20?×?7/2?cm² with a V-shaped bottom. The samples were analyzed using atomic absorption. The experimental results showed that eliminated metal percent by oak powder, gall nut, and bacterial exopolymer were, respectively, of 94.8%, 96%, and 13.8% for Hg and 7.8%, 4.4%, and 69.4% for Cs. The tests revealed that Ca⁺⁺, when used as flocculant, played a key role in both biosorption and bio-precipitation rates. Consequently, it was concluded that the investigated biosorbents could be use as an integrated biosorption system for the refinement of mixed wastes.     

An improved optimization model for predicting Pb recovery efficiency from residual of liberator cells: a hybrid of support vector regression and modified tunicate swarm algorithm

Journal of Material Cycles and Waste Management - In this study, a hybrid of support vector regression and a modified tunicate swarm algorithm (SVR-MTSA) strategy is developed to optimize the...     

Tailoring a non-path-dependent model for environmental risk management and polycentric urban land-use planning

This study attempts to develop a non-path-dependent model for environmental risk management and polycentric urban land-use planning in Gorgan Township area, Iran. Applying three suitability layers of environmental risk (soil erosion, flood risk, fire risk, and land susceptibility), urbanization potential, and integrated surface (environmental risk plus urbanization potential layers), a non-path-dependent Cellular Automata-Markov Chain (CA-MC) model was configured to execute three scenarios of polycentric urban growth allocation. Specifically, the modeling approach improved the traditional functionality of the CA-MC model from a prediction algorithm into an innovative land allocation tool. Besides, due to its flexibility, the non-path-dependent model was able to explicitly include different characteristics of the landscape structure ranging from physical land attributes to landscape functions and processes (natural hazards). Accordingly, three polycentric urban growth allocation efforts were undertaken and compared in terms of connectivity and compactness of the resultant patterns and consumption of other land resources. Based on results, the polycentric allocation procedure based on integrated suitability layer produced a more manageable pattern of urban landscape, while the growth option based on environmental risk layer was more successful for protecting farmlands against excessive urbanization. This study suggests that polycentric urban land-use planning under the strategy of rural land development programs is an available option for designing an urban landscape with lower exposure to natural hazards and more economic benefits to rural residents. Finally, the non-path-dependent modeling is a recommended approach, when highly flexible and interactive decision-support systems as well as trend-breaking scenarios are desired.     

Trophic transfer of CuO nanoparticles from brine shrimp (Artemia salina) nauplii to convict cichlid (Amatitlania nigrofasciata) larvae: uptake,accumulation and elimination

Environmental Science and Pollution Research - We investigated the trophic transfer potential of CuO-NPs from Artemia salina to Amatitlania nigrofasciata. The Cu uptake was investigated by exposure...