Effects of lead sub-lethal concentration on blood iron content of the common carp, Cyprinus carpio

In order to examine the effect of lead on the iron content of blood, sampling of common carp was carried out randomly from a fish culture pond in southeast of Babol by purse seine, in 2008. First of all, the experimental fish were adapted to laboratory conditions for 48 hours. Then, the effect of different concentrations of lead were examined using 3 experimental (A: 4.296 mg/l, B: 7.127 mg/l, C: 8.656 mg/l) and one control groups. There were 12 aquariums, each containing 12 fish. It was tried to apply an equal environmental condition for all of the aquariums during the experiment. Following 24, 48, 72 and 96 hours of exposure, fish were anesthetized and blood samples were taken from caudal vein. The fish average weight and length (total length) were 140.5 g, 21.8 cm, respectively. Concentrations of lead and iron have been determined by ICP-OES after acid digestion of blood samples by Microwave. This study showed that the absorption of lead and its concentration in the blood significantly increased (p<0.05) as the time passed compared to the control group. However, there was no significant trend since the blood acts as a carrier of heavy metals such as lead to the target organs. There was also no significant relationship (p<0.05, n=3) between increasing the amount of absorbed lead and blood iron changes. Therefore, it may be concluded that there is no interaction between blood iron and lead concentration. Increasing trend of blood iron concentration during the experiment was also probably because of some physiological changes resulting from stress in fish

Quantum cascade laser-based sensors for the detection of exhaled carbon monoxide

Contains fulltext : 156873.pdf (publisher's version ) (Open Access

Soil nutrient status, nutrient return and retranslocation in poplar species and clones in northern Iran

In this study several same-aged poplar species and clones were selected including Populus deltoides Marsh. CV. “Lux” (P.d “Lux”), Populus deltoides Marsh. CV. “Harvard” (P.d “Harvard”), Populus x canadensis Moench “Triplo” (P.xc “Triplo”), Populus x canadensis Moench “I-45/51” (P.xc “I-45/51”), planted in poplar research station about 20 years ago in the north of Iran, and Populus caspica Bornm. (P. caspica) as endemic and endangered poplar species. Some quantitative characteristics of the trees and soil samples were taken based on completely randomized block design. Samplings of live and senescent leaves were carried out in two-stages, mid-summer during the peak nutritional activities of trees and mid-autumn for senescent leaves. Soil samples were analyzed to determine organic carbon (OC), total nitrogen (N), available phosphorus (P) and exchangeable potassium (K). OC, total of N, P and K were also determined in live and senescent leaves. The results showed that P.d “Harvard” had the highest total height, DBH and diameter of crown compared to the other species and clones. The amount of OC, N and P in soil and live leaves of P.d “Harvard” clone are more than those of the other species and clones. OC, N, P, and K returned by senescent leaves were higher and lower for P.d “Harvard” and P. caspica respectively. P retranslocation for all of the clones and species was higher compared to N and K. The highest retranslocation percentage was observed in P. caspica (N=18.93, P=39.63, K=24.02) and the lowest (N=12.09, P=32.46, K=21.14) in P.d “Harvard” clone. It could be concluded that poplar species and clones have different nutritional requirements and retranslocation capabilities. It appears that P.d “Harvard” clone showed higher quantitative growth it could be beneficial for maintaining the soil nutrient status for successive plantings

Antibiotic Resistance Index of Heterotrophic and Coliform Bacteria in Water and Sediment of Goharrood River

Introduction Overuse of antibiotics and their entry into the environment is a global concern today. Much of the antibiotics taken by animals and humans are excreted unchanged and found in their feces which enter the environment through livestock waste and municipal wastewater disposal. Uncontrolled release and continuous introduction of antibiotics to the environment induced antibiotic resistance in microorganisms living in other habitats which pose a potential hazard to existing aquatic ecosystems and animals. Rivers act as the main sink for the effluents that distribute antibiotics and antibiotic resistant microorganisms in the environment. This study aimed to investigate the antibiotic resistant index (ARI) in Goharrood River. Seasonal variations and source of contamination, focusing on urban surface wastewater of Rasht, were investigated through sampling of river water and sediment in different points along the river during four seasons of a year.Materials and MethodsThe water and sediment of the river were sampled at three points along the river (focused on river course in Rasht city), in autumn, 2016 and in winter, spring and summer, 2017. The number of antibiotic resistant heterotrophic and coliform bacteria were counted via colony count method in the antibiotic supplemented 100 µg/mL Nutrient Agar and Eosine-Methylene Blue agar media respectively. Cephalexin, gentamicin, doxycycline, ciprofloxacin, and trimethoprim antibiotics were tested in this study. ARI was calculated by dividing number of bacteria colonies (heterotrophic and coliform bacteria) in plates supplemented with antibiotics to the number of colonies in control plate (without antibiotic). Escherichia coli as an indicator coliform bacterium was isolated from water and sediment samples (12 strains; 4 season and 3 sampling points) and their resistant pattern to these antibiotic was also tested by disk diffusion (Kirby-Bauer) method in Mueller-Hinton agar medium. The inhibition zone (ZOI) of E. coli growth was measured and its sensitivity/resistant was assessed based on CLSI standard protocol. The calculated ARI of heterotrophic and coliform bacteria of water and sediment of the River and the determined ZOI of E. coli isolated from water and sediment were analyzed by repeated measures of factorial arrangement in a completely randomized design format by SAS software package. Factors included sampling point at 3 levels (before entering river to the Rasht city; A, in the Rasht city; B, and after river exit from the Rasht city; C), and antibiotics at 5 levels (cephalexin, gentamicin, doxycycline, ciprofloxacin, and trimethoprim) as main plot and sampling time at 4 levels (autumn, winter, spring, and summer) as sub-plot.Results and Discussion The highest ARI value of water heterotrophic bacteria was obtained to cephalexin at the sampling point C. Mean ARI of water heterotrophic bacteria to all antibiotics (regardless of type of antibiotic) at three points of A, B and C was 3.77, 4.54 and 7.53%, respectively. The highest ARI levels of heterotrophic and coliform bacteria in water were obtained in the summer season. In fact, the change of seasons and clearly the summer season controlled the ARI in water bacteria rather than the type of antibiotics. So that in this season 30.78% of water heterotrophic bacteria were resistant to ciprofloxacin antibiotic and about half (50.78) of the river water coliforms were resistant to cephalexin. Although ARI for heterotrophic and coliform bacteria was lower in sediment rather than that in water, the highest ARI levels of heterotrophic and coliform bacteria in sediment were obtained against cephalexin in autumn and winter, respectively. In general, the mean ARI in water and sediment bacteria was as follows: cephalexin > gentamicin > ciprofloxacine > doxycycline > trimethoprim. The lowest ZOI value for E. coli was obtained against cephalexin. Therefore, in all three sampling points, isolated E. coli bacteria from water and sediment were resistant to cephalexin. In the study of the sampling time and sampling point interaction, it was also seen that the lowest ZOI of E. coli was in autumn and at sampling point C. Therefore, it seems that E. coli has become resistant to antibiotics when river crosses the city.Conclusion According to the results of this study, Goharrood river is contaminated with antibiotic-resistant, especially cephalexin resistant bacteria and it may distribute pollution downstream. If the river water is used in aquaculture and irrigation of downstream agriculture fields, the antibiotic resistant bacteria may be spread in the other ecosystems and finally may enter the human food chain

Investigation of the effects of the conversion of forests and rangeland to cropland on fertility and soil functions in mountainous semi-arid landscape

Soil fertility and (micro)biological activities are prominent indicators of soil ecological functions interrelated with nutrient cycles and stocks. The responses of soil functions and belowground biota to degradation of natural ecosystems and land use changes have received little attention, especially in semi-arid ecosystems of mountainous areas that are sensitive and fragile habitats. Soils were sampled from two natural vegetation types: forest (Carpinus orientalis - Zelkova carpinifolia) and rangeland (Berberis integerrima - Crataegus melanocarpa), and two cultivated croplands (under Triticum aestivum), located in a mountainous semi-arid region of northern Iran, that were converted from the forests and rangelands thirty years ago. Soil properties, C and N stocks and fractions, and related microbial activities were analysed in 0–10 and 10–20 cm. C stocks in the upper 10 cm soil were affected by land use, while no differences were found in the lower depth. C stocks in the topsoil reached 49, 37, 33 and 29 Mg ha−1 for forest, rangeland, croplands (converted from forest and converted from rangeland), respectively. Soil N stocks under forest (5.2 Mg ha−1 for top 10 cm and 4.8 Mg ha−1 for 10–20 cm depths) were higher compared to the other land use types. Particulate and dissolved organic matters under croplands were almost half of that under forest and rangeland. High soil respiration, microbial biomass, ammonium and nitrate content, as well as N mineralization in 0–10 cm under forest were 2 times larger than in 10–20 cm. Concluding, conversion of forest and rangeland to croplands (converted from forest &gt; converted from rangeland) has decreased the functions of soil due to removal of tree cover, decreasing litter layer, organic matter input and soil moisture and also increase of soil temperature. Consequently, more care should be taken by preserving natural vegetation in mountainous semi-arid ecosystems, and higher organic inputs are necessary to maintain microbial properties and functions. © 2021 Elsevier B.V

Evidence of Ferromagnetic Behavior of Small Liquid Droplets Produced from Amorphous Alloys by Laser Ablation

Experimental evidence of ferromagnetic behavior of liquid droplets produced by laser ablation from amorphous alloys is presented. Thin films of amorphous magnetic materials were fabricated by laser ablation deposition in the presence and in the absence of a magnetic field. The difference in parameters of deposited films is attributed to ferromagnetic properties of small size liquid droplets