The current study aimed to synthesize, characterize and determine the antibacterial activity of iron oxide (Fe3O4 NPs) and silver nanoparticles (AgNPs) green-synthesized using Fusarium solani. Fungal mass was applied to produce NPs, followed by analyzing NPs using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Theantimicrobial test was performed by the agar well diffusion method and the microdilution protocol (determining the minimum inhibitory concentration or MIC and the minimum bactericidal concentration or MBC) against Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa and Escherichia coli. The highest optical densities for produced AgNPs and Fe3O4 NPs were detected at 420 and 215 nm, with a spherical shape and size of 27.5-58.3 nm and a cubic-spherical shape and size of 55.3-84.2 nm, respectively. Ag NPs had more antibacterial activity than Fe3O4 NPs, but they were not significantly different in most cases. The most sensitive and resistant bacteria were S. aureus and P. aeruginosa for both NPs, with the MIC of 10 and 40 μg ml-1 as well as the MBC of 20 and 80 μg ml-1 for Ag NPs against S. aureus and P. aeruginosa, respectively. The results were weaker for Fe3O4 NPs than for Ag NPs, with the MIC of 20 μg ml-1 for B. cereus and S. aureus, and 40 μg ml-1 for P. aeruginosa and E. coli, with the MBC of 40 and 80 μg ml-1, respectively. The antibacterial properties of the produced NPs indicated that these antimicrobial agents were highly reactive and prevented the growth of unwanted microorganisms. پرونده مقاله

The estimation of carbon storage and accumulation in forest ecosystems is essential to assess the role of these ecosystems in the global carbon budget. Therefore, we considered the potential and distribution of organic carbon in the natural pure and mixed beech, oak and maple forests of Fandogloo region of Ardabil province in Iran. In each stand, 6-nested plots were used in the square shape. Four profiles were dug in each plot and the soil samples were extracted from the three deep levels. The highest amount of soil organic carbon sequestration was found in the mixed stand of oak-maple (26.35 Mg/ha). The same trend was seen in the amount of total nitrogen (TN) in the soil. The highest amount of carbon sequestration was observed in the forest floor litter in the mixed stand of maple - beech (4.11 Mg/ha). The high amount of carbon sequestration in the mixed stand of oak - maple may be due to the lower amount of clay in the soil of this stand. It is likely that the soil fertility is low in the maple–beech stand so that the activities of microorganisms are less than other stands so that due to no degradation, the accumulation of litter has occurred. Totally, the pure beech stand showed the highest amount of total carbon sequestration in the entire pure stand (61.93 Mg / ha). The high above- and belowground biomass in the beech stand was the effective factor to increase the total carbon sequestration than other stands. پرونده مقاله

A critical aspect of qualitative management of water resources is the optimal waste load allocation in a river system. Zarrineh Rud is one of the crucial, permanent, water-rich rivers in West Azerbaijan province in the northwest of Iran and the Urmia lake basin. In this study, with the aim of quality management of Zarrineh Rud river, QUAL2K computer simulation model was used. The simulation parameters in this study included discharge, DO, BOD, NO3, NH4, PO4, which were collected from 5 sampling stations S1, S2, S3, S4 and S5 in spring and summer. The results showed that the amount of oxygen saturated solution of Zarrineh River varied between 7-8 mg / l, which is higher than the maximum standard value required. The results showed that BOD could increase by 16% in spring and summer, respectively, and should decrease by 70% in summer to meet the required standard. The station S5 at the river downstream with 3.53 mg/L dissolved oxygen deficit was the most critical point for cold-water fish farming, and the 26th kilometer of the river with a dissolved oxygen deficit of 2.05mg/L was the most critical point for maintaining the aquatic life; therefore, some scenario must be developed for waste load reduction at this station. In order to improve the quality of Zarrineh River, construction of a wastewater treatment plant is necessary for Miandoab sugar factory, villages adjacent to the river and also slaughterhouse. پرونده مقاله

Increasing population growth and civilization have caused great impacts on water quality. Among these, changes and excessive exploitation of land use have led to changes in the surface water quality to provide human needs. Therefore, the present study investigated the effects of land use on water quality using a spatial-statistical approach. To this end, the water quality data of 22 water quality-sampling stations were applied in the Qarasu watershed in Ardabil in 2013, Iran. Then, spatial analysis was conducted, including land use classification maps, watershed mapping and overlaying maps using GIS. Finally, correlation and multiple linear regression analysis were used to determine the relationship between water quality and land use variables. Pearson's correlation coefficient showed proper percentages of vegetation cover, agricultural lands, woodlands, residential users, barren land and forest as well as weak pastureland have significant correlation with water quality variables. Multiple linear regression analysis with stepwise approach also indicated that of dependent parameters as water quality variables, the parameters of pH, Cl, Ca, Mg, Na and SAR are associated with land use as independent parameters including irrigated agriculture, first-grade pasture, third-grade pasture, woodlands, moorland, forest and residential users. Furthermore, validation of the model based on two models of the survey of predicted and actual values as well as root-mean-square error (RMSE) demonstrated good accuracy of the resulting model. پرونده مقاله