Magnetic Solid-Phase Extraction Based on Modified Iron Oxide Nanoparticles for the Preconcentration of Ultra-Trace Amounts of Copper Ions in the Environmental and Plant Samples and its Determination Using FAAS

In the present work, magnetic iron oxide nanoparticles (MIONPs) coated with sodium dodecyl sulfate (SDS) and modified with 1-(2-pyridylazo)-2-naphthol (PAN) as a new nanoparticle were prepared and used as an adsorbent for the extraction and preconcentration of copper ions. After adsorption, copper ions were desorbed with nitric acid (HNO₃), followed by determination with flame atomic absorption spectrometry (FAAS). The extraction conditions0. were investigated systematically. The linear range 3.0–500.0 ng mL^?1 and the detection limit of 0.6 ng mL^?1 were obtained. The relative standard deviation (RSD) of the method for seven replicate determinations of 0.1 µg mL^?1 of Cu(II) was 2.2%. The method was applied for the determination of Cu(II) in different water samples with good trueness. The accuracy was also evaluated through analyses of a certified reference material (CRM TMDW-500).     

Graphite Furnace Atomic Absorption Spectrometry After Dispersive Liquid–Liquid Microextraction for the Determination of Selenium in the Anodic Slime

In the present study, a method based on dispersive liquid–liquid microextraction (DLLME) followed by graphite furnace atomic absorption spectrometry (GFAAS) determination was proposed for the determination of selenium by using ammonium pyrrolidine dithiocarbamate (APDC) as the chelating reagent. The main factors influencing the DLLME were investigated systematically. Under the optimal conditions, the limit of detection for Se(IV) was 0.02 ng mL^?1. The relative standard deviation was 4.1% (C_Se(IV) = 0.2 ng mL^?1, n = 8) with an enhancement factor of 135.8-fold from only 5 mL of the water sample. The proposed method was successfully applied to the determination of Se(IV) in anodic slime and electrolyte samples. In order to validate the proposed method, a Certified Reference Material (trace elements in water, 1643e, NIST) was analyzed, and the determined value obtained was in good agreement with the certified value.     

Estimation of a basal area growth model for individual trees in uneven-aged Caspian mixed species forests

The aim of this study was to estimate a basal area growth model for individual trees in uneven-aged Caspian forests. A survey was conducted in order to find a natural forest without any harvesting activities, a so called ‘untouched forest’ and an area was selected from the Iranian Caspian forest. Three sample plots in the same aspect and of the same forest type were selected. In each plot, total tree height, diameter at breast height, distance of neighbor trees and azimuth were measured. Thirty trees were selected and drilled with increment borer to determine the increment model. Regression analysis was used to estimate the growth model. Results show that, for individual trees, there is a significant nonlinear relationship between the annual basal area increment, as the dependent variable, and the basal area. The results also show that the basal area of competing trees has a positive influence on growth. That the increment is higher with more competing neighboring trees is possibly because plots with higher volume per hectare and more competition, most likely also have higher site index or better soil or better site productivity than the plot with lower volume per hectare.     

Exogenous Spermidine Affected Leaf Characteristics and Growth of Common Bean Under Water Deficit Conditions

In order to investigate the effects of exogenous spermidine on water limitation-induced damage on common bean (Phaseolus vulgaris L.) genotypes, a field experiment was conducted over two growth seasons. The experiment was arranged as a split-split plot design and three replications. Treatments were three water stress levels (non-stress, moderate and severe stress), three bean genotypes (Akhtar, Pak and COS12) and two spermidine levels (control and foliar application). The results showed that water stress reduced markedly leaf relative water content, SPAD values, specific leaf area, leaf area index, plant height, relative growth rate, shoot dry weight and grain yield; however, increased leaf density, leaf relative electrolyte leakage, stomatal density, leaf angle and leaf temperature of bean genotypes. Spermidine application increased relative water content, SPAD values, leaf area, leaf area index, shoot dry weight and grain yield. Overall, exogenous spermidine usage as a free radical scavenger counteracted deleterious water deficit effects.     

Preparation of Modified Magnetic Cobalt Nanoparticles as a New Magnetic Sorbent for the Preconcentration and Determination of Trace Amounts of Lead Ions in Environmental Water and Soil (Air-Dust) Samples

In this study, cobalt magnetic nanoparticles (MNPs) were synthesized and then modified by sodium dodecyl sulfate (SDS) and 2-(5-bromo-2-pyridylazo)-5-diethyl aminophenol ligand (5-Br-PADAP), through a chemical precipitation method. Characterization of the prepared MNP adsorbents was performed by Fourier transform infrared and transmission electron microscopy. Cobalt nanoparticles (NPs) surface modified with SDS and 5-Br-PADAP was evaluated as a nanoparticulate solid-phase extraction (SPE) absorbent for lead ions Pb(II) from water and standard samples, prior to its flame atomic absorption spectrometry determination. Effects of pH, amount of sorbent, desorption solvent, adsorption time, desorption time, and interfering ion concentration on extraction efficiency were investigated. Under optimal conditions, the calibration curve was linear in the range of 1.0–500 ng mL^?1of Pb(II) with R² = 0.998. Detection limit was 1.6 ng mL^?1 in the original solution (3S_b/m), and the relative standard deviation for replicate determination of 0.5 μg mL^?1 Pb(II) was ±2.7%.     

Effects of freeze and cold stress on certain physiological and biochemical traits in sensitive and tolerant barley (Hordeum vulgare) genotypes

An experiment was performed as a split-plot design based on a randomized complete block (RCB) with three replicates. The aim was to explore physiological traits, catalase (CAT) and peroxidase (POD) activity associated with cold and freeze stress in four barley genotypes (two stress-tolerant genotypes and two sensitive genotypes). The genotypes were regarded as sub-plots and five temperature levels (namely 20, 4, 0, ?4, ?8°C) as main plots. The results revealed that the hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) content increased through freeze and cold stress from 20 to 4°C. This increase was more in the sensitive genotypes than in the tolerant ones. Subsequent to the increase in lipid peroxidation, the membrane stability index (MSI) decreased, thereby increasing the electrolyte leakage. The sensitive genotypes demonstrated greater reduction in the studied parameters. Upon the increase in the H₂O₂ content, the antioxidant enzymes CAT and POD also increased in order to collect and prevent H₂O₂ from damaging the cell and the plant. Compared with the sensitive ones, the tolerant genotypes indicated more increase in the enzymes. The H₂O₂ and MDA content decreased from ?4 to ?8°C, which could be due to intracellular freezing in the sensitive genotypes, but due to the detoxifying of the antioxidant enzymes in the tolerant genotypes. Compared with the POD content, the increase in the CAT content through cold stress was more, which could mean that it was possibly CAT which acted as the main inhibitor of H₂O₂ in cold stress in the barley plant.     

Distribution of Cr,Ni and Co in soils and rocks of Neyriz area (Iran): the influence of ophiolitic formations

Neyriz area, on south of Neyriz ophiolite complex, is one of the most important areas in fruit production. However, no study has been yet performed to assess the contamination status of soils in this region. The objective of the present study was to explore soil pollution by Cr, Ni and Co. Three landforms (ophiolite hills, alluvial fan and playa) were selected along a transect. Seven pedons were excavated and soil and rock samples were obtained. The total concentration of Cr, Ni and Co, Enrichment Factor (EF) and Geo-accumulation index (I_geo) were determined. Results showed that soils over ophiolite hills and alluvial fan were extremely polluted by Cr and Ni (I_geo=3–6). The EF Index confirmed that heavy metals originated from ophiolite rocks in the region. Both indices showed a descending trend from ophiolite hills to playa that related to deposit transportation processes during landforms evolution. It was also observed a decreasing vertical trend in metal contents in the soils over alluvial fan which can be attributed to the long-time irrigation and plant uptake as affected by land use. Further investigation is needed to understand the contamination status of ground-water and orchards of the region to achieve sustainable management.     

Effect of date palm (Phoenix dactylifera) seed extract as a dietary supplementation on growth performance immunological haematological biochemical parameters of common carp

This study aimed to assess the effect of date palm (Phoenix dactylifera) seed (DPS) extract at 0.5%, 1%, 2% and 4% as a dietary supplement over 60 days, on the growth and immune‐physiology of common carp (Cyprinus carpio) fingerlings. The weight gain in fish fed with 0.5% DPS was significantly greater than other treatments and fish fed a control diet with no DPS (p < 0.05). With increasing DPS dosage above 0.5%, weight gain and growth rate gradually declined. Feed conversion ratio in fish fed 0.5% DPS was lower than other treatments, but not significantly so, except for the highest DPS concentration (4%). With respect to immunophysiological variables, fish treated with 0.5% DPS leucocyte, neutrophil, lymphocyte and monocyte counts that were generally equivalent to fish on a control diet, but significantly lower than fish treated with greater concentrations of DPS (p < 0.05). Chemilumincene response and lysozyme activity, as well as levels of total protein and albumin, were higher in all treated groups than the control. The highest levels of iron and high density lipoprotein (HDL) were observed in fish fed with 0.5% DPS, while the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), glucose, cholesterol, triglyceride, low density lipoprotein (LDH), thyrotropin, thyroxine and triiodothyronine were lower level in fish fed with 0.5% DPS than in all other treatments. In aquaculture practice, use of 0.5% DPS in commercial carp feed can improve the growth rate and condition of fish.