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In this paper, results of the study on heavy metals solubility behavior of Ni-Cd filter cakes in Iranian Zinc Mine Development Company (IZMDC) plants are investigated. The effects of pH, temperature, liquid/solid ratio and contact time on the release of heavy metals (Zn, Cd, Ni and Pb) into water media was examined. Also, “Extraction procedure tests” approved by EPA were applied to the residues. Moreover, statistical data analysis was performed and the most important parameters for dissolution of Zn, Cd, Ni and Pb were found to be the pH and L/S.. The concentration of Cd and Pb in the extracts obtained from filter cakes by applying EPA extraction procedures at pH 5 are over 1.0 and 5.0 mg/L, which are toxicity limits, respectively. The concentrations of other metals in the solution are above the limits given by various quality standards for surface water.

 

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Cotton (Gossypium hirsutum L. cv. Varamin ) an important industrial crop of Iran, is grown in 300,000 ha, with an average seed -cotton yield of 1750 Kg.ha-1. The main obstacle in the way of increasing average cotton yield is imbalanced fertilizer use. Along with urea and triple super phosphate, cotton growers also need K, Mg, Zn, Fe, Mn, Cu, and B, so these elements’ critical levels should be determined in cotton fields. Field experiments were conducted in 12 different fields in 1997 to determine critical levels of Fe, Zn, and B in soil, and to study the effects of these micronutrients on the yield and quality of cotton in Varamin region. The experiment design was a randomized complete block one (RCB) with four treatments and three replications. Treatments were; NPK, NPK+Fe, NPK+Zn, and NPK+B. Iron was applied as FeEDDHA (20 kg.ha-1), Zn as zinc sulfate (40 Kg.ha-1), and B as boric acid (20 Kg. ha-1) prior to planting. Average seed cotton yield, lint yield, seed index, and boll weight increased significantly by adding Fe, Zn, and B. In a cotton field with higher soil B concentrations, cotton yield decreased with B fertilizer. Critical levels of Fe, Zn, and B were determined based on Cate-Nelson graphical and analysis of variance methods. In graphical method critical levels of Fe, Zn, and B were 4.8, 1.1, and 1.0 mg.Kg-1 soil, respectively, while on the basis of analysis of variance method, these levels were 5.5, 1.1, and 1.3 mg.kg-1 soil, respectively. In one field, boll shedding decreased by Zn and Fe treatments but was not affected by B addition. Iron to Zn ratio in cotton leaves increased at Fe treatment and decreased in Zn treatments. Boron treatment increased B content of leaves. Furthermore, zinc sulfate decreased B toxicity in the cotton leaves. In short, applying micronutrients increased quality and yield of cotton in Varamin region.

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Research subject:
Zinc is one of the most dangerous organic components in industrial wastewaters, which pollutes the environment as a result of human activities and various industrial operations. In the present study, the adsorbent prepared from Gracilaria Corticata algae was used for the first time to recover and remove heavy metal zinc and equilibrium study of the process were done.
Research approach:
In the current work, the effect of important parameters such as initial pH of solution, adsorbent dosage and contact time were investigated on the adsorption efficiency of the process. Additionally, Langmuir and Freundlich two-parameter adsorption isotherm models were used to model the equilibrium of zinc adsorption.
Main results:
The results showed that according to the calculated correlation coefficient, Freundlich isotherm was better than the Langmuir in fitting the experimental data. The highest point-to-point correlation coefficient for adsorbent percentage was achieved at 3 g/ml adsorbent dosage with contact time of min 360 and pH=7 and the lowest one was at 4 g/ml adsorbent dose with contact time of min PH=360 and 7. However, the highest adsorption rate was observed for the adsorbent dosage of 4 g/ml with contact time of 420 min at pH=9 and the lowest adsorption percentage was achieved at the adsorbent dosage of 2 g/ml with contact time of 300 min and pH=5. The maximum and minimum adsorption percentages were 76.88 mg/g and 49.25 mg/g, respectively

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Research subject: In recent years, researchers have proposed various methods for gas separation because of rising greenhouse gases in the atmosphere and causing enormous environmental problems. One of the newest and emerging methods is membrane gas separation. In the last decade, mixed matrix membranes (MMMs) have received much attention due to their ability to successful separation of polar gases from mixtures.
Research approach: In this study, a novel two-component mixed matrix membrane was prepared by incorporating the nickel zinc iron oxide nanoparticles into the Pebox polymer matrix. This is owing to combination the unique features of Pebax copolymer such as high mechanical strength and gas permeability, with nanoparticle properties as considerable permeability and selectivity, and appropriate mechanical and thermal stability. The gas permeability test was performed for pristine membrane and MMMs at 35 °C and pressure range from 2 to 10 bar. Fabricated membranes were also evaluated by FESEM, FTIR-ATR, DSC and XRD tests
Main results: Results demonstrated that in the case of the optimum membrane with 1 wt.% of filler loading and at 10 bar, the CO₂ permeability was increased about 128% and reached to 278 Barrer, compared to pristine membrane. However, the CO₂/CH₄ and CO₂/N₂ selectivities were improved by 175 and 183 percent, respectively. This superior results was due to the presence of iron, nickel, and zinc atoms in the filler structure, which resulted in a better interaction with CO₂. On the other hand, the presence of CO₂-friendly segments in the Pebax structure caused much higher CO₂ permeability in comparison with other light gases.

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Research subject: In this research we studied the anti-corrosion properties of epoxy coating containing anti-corrosion pigment zinc phosphate with hydrophobic nano silica with different percentage also for determine the optimal conditions for preparation of nanocomposite Taguchi experimental design method was used.
 
Research approach: Anti-corrosion properties of epoxy coating under the influence of very important factors such as the percentage of nano silica, anticorrosive pigment and pigment to resin ratio according to model L9 taguchi method was studied and analyzed. Anti-corrosion properties of epoxy coatings were studied by electrochemical impedance spectroscopy test (EIS) in 3/5% NaCl aqueous solution and salt fog test (salt spray). To investigate the distribution of nano silica particles in epoxy resin were analyzed by transmion electron microscope (TEM) and scanning electron microscope (SEM). The results show that using from zinc phosphate and nano-silica was able to improve the corrosion resistances.
 
Main results:Results shows that addition of zinc phosphate and nano silica to epoxy resin caused a decrease in number of blisters and corrosion products after exposure to corrosion test based on the results in Nyquist and Bode plots, also the similarity in results was observed for the epoxy coating loaded according to the optimum conditions with 8% zinc phosphate, 3% nano silica and pigment to resin ratio of one according to salt spary. The significance levels of the experimental parameters, which indicate how the factors affect the compressive addition of zinc phosphate and nano silica to epoxy resin, were determined by using variance (Anova) method.

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Metformin enhances insulin's effect and increases cells’ sensitivity to insulin. In this paper, nanocomposite was designed and used in the metformin release system, which was able to release the required drug in a controlled manner. In this research, nanoparticles of zinc oxide (ZnO) were prepared via the sol-gel method. The experimental design central composite response surface method was applied for the optimization of the nanoparticles based on varied variables such as the weight of zinc acetate (gr) (X ₁) and the volume of triethanolamine (ml) (X₂). The particle size of the optimized nanoparticle was reported to be 28 ± 21.27 nm; zeta potential and PdI were 25.54 ± 1.64 mV, 0.168 ± 0.05 respectively. The chitosan polymer was used to improve environmental compatibility and increase drug release control; finally, metformin was loaded on the optimized nanocomposite. Structural properties were analyzed using scanning electron microscopy (SEM) X-Ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and Dynamic Light Scattering (DLS). The SEM images showed that the average nanocomposite size was 40 nm. The results of XRD patterns and SEM images were also consistent with each other and the average particle size was the same. Infrared spectrophotometry showed the presence of chitosan used to coat nanoparticles on their surfaces and confirmed the loading of metformin. An in-vitro metformin release from the nanocomposite was conducted in PBS (pH=7.4) and analyzed by a spectrophotometer at 233 nm. Metformin has a high solubility in water, and since it is difficult to prepare a slow release form of high-solubility drugs, the aim of this study was to design a slow-release formulation of metformin with a suitable profile that could control release without explosive release for up to 120 hours.

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Effects of fortification Setareh flour with iron, folic acid, zinc and calcium on chemical properties (dry gluten, wet gluten, gluten index, protein and zeleny value), rheologocal properties (water absorption, dough strength, dough extensibility, dough loses after 10 and 20 minutes, resistance to extensibility, extensibility index, maximum height of curve and energy), was considered in Barbary breads and compared with control treatment. In this study we have 4 treatments as follows: 1- Setareh pure flour without any fortificant/ as control. 2- Flour which fortified with low dosage of fortificants : (ferrous sulfate 20, folic acid 1.5, zinc oxide 20 and calcium carbonate 900 p.p.m). 3- Flour which fortified with middle dosage of fortificants : (ferrous sulfate 30, folic acid 2, zinc oxide 30 and calcium carbonate 1200 p.p.m). 4- Flour which fortified with high dosage of fortificants : (ferrous sulfate 40, folic acid 2.5, zinc oxide 40 and calcium carbonate 1500 p.p.m). Statistical data have shown that, in all mentioned properties flour treatments fortified with minimum and middle amounts of fortificants had better results than the flour which fortified with maximum amounts of fortificants. Minimum and middle treatments didn’t have any significant differences, so with due attention to international organizations (WHO, FAO) and provide vital micronutrients for body, we propose middle treatment.

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Gas sensitive metal oxide layers used in fabrication of resistive gas sensors are prepared by different deposition techniques. The technical data reported on some basic and practically important specifications of these devices, although fabricated based on the same gas sensitive oxide, are anomalously different. The influence of the fabrication technique used for the deposition of the gas sensitive layer on determination of the significant specifications of the transient response of a resistive gas sensor is experimentally investigated for the first time. ZnO and SnO2 layers were prepared by LPCVD, PVD, EPD and powder pressing techniques. Prototype gas sensors based on these layers were fabricated. The transient responses of these devices to a step change in the composition of the surrounding atmosphere were recorded and compared. It was shown that the thickness, porosity and pore micro-structure of the gas sensitive layer are the most effective parameters in determination of the transient response. The relationship between these parameters and the temporal variation of the electrical conductivity of the gas sensitive layer was qualitatively analyzed. Oxide layers of higher porosity resulted in gas sensors of faster response, but response time increased with the thickness of these gas sensitive layers. The sensors produced by EPD technique demonstrated the fastest responses while those produced by CVD were the slowest among the samples investigated.

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The rise of bacterial infections has become a serious problem in human societies. As a result, the development of nanocomposite materials based on biocompatible and non-hazardous materials, besides having antimicrobial and biocompatibility or non-cytotoxicity, associated with unique structural properties, possesses a great importance. Research approach: In this study, bacterial cellulose (BC)/polypyrrole (PPy) and zinc nanoparticles (ZnO), which simultaneously have antimicrobial properties and cell proliferation, were introduced as a new generation of nanocomposite scaffolds produced by freeze-drying. To begin with, ZnO with different weight percentages of 1%, 3% and 5% was added to BC and then PPy in the amount of 2 mmol was embedded in the structure by in situ polymerization. FESEM images proved that the nanofibrous and porous structure of BC was also preserved in the presence of PPy and ZnO. However, after adding PPy and ZnO, they formed a dense structure and microstructure of grape clusters. By adding 2 mmol PPy into BC and upon in situ synthesizing, the tensile strength and Young modulus of BC were significantly reduced to 71 MPa and 2.5 GPa, respectively. On the other hand, with the addition of ZnO nanoparticles, the mechanical properties significantly increased (both of Young modulus and tensile strength compared to BC/PPy samples) due to the compaction of the nanocomposite aerogel’s structure and the formation of the interface of ZnO nanoparticles with both polymers of BC and PPy. The observation of the inhibition zone in the culture medium containing two gram-positive and negative bacteria, well proved the antibacterial ability of ternary nanocomposite scaffolds. The results of MT9 related to L929 on aerogels showed that by adding 3% of ZnO nanoparticles, adhesion and cell proliferation increased significantly during different days of 1 day, 5 days and 7 days of culture.

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Abstract: Toxic metal pollution is effluents from hospitals and factories. Remove them from the environment is important. Iranian Research Organization for Science and Technology of yeast Saccharomyces carlsbergensis PTCC 5051, and received as a lyophilized culture YEDPA environment and then the proliferation of malt extract broth is used. In this study, the effects of parameters such as pH, temperature, kinetics and adsorption isotherm nickel and zinc were determined by Saccharomyces. Maximum amount of nickel and zinc uptake in the pH range 5/5, and 6 was respectively. Kinetic studies showed that the biological uptake of nickel by biomass on Saccharomyces was quickly removed and most of the first test was done in less than 30 minutes. Adsorption of nickel and zinc were determined by Saccharomyces active and in active. Uptake by yeast is more active. Nickel and zinc uptake by Saccharomyces inactivated by autoclaving or sodium azide and di-nitro phenol has been investigated. Maximum amount of nickel and zinc absorption were 0.65 and 0.47 mmol g. Remove toxic heavy metals from wastewater by the yeast Saccharomyces hospitals is high performance.

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Aims: Essential oils are a complex of volatile compounds obtained from different parts of plants. Cinnamon (Cinnamomum zeylanicum) essential oil (EO) is known as a suitable source of antibacterial compounds. The aim of present study was to investigate the antibacterial activity of cinnamon EO and ZnO nanoparticles (NPs) against 2 strains of Listeria monocytogenes.
Materials & Methods: In this experimental study, 2 strains of L. monocytogenes (a standard strain and a fish isolated strain) were used. The antibacterial activity of cinnamon EO and ZnO NPs was assessed by well diffusion test. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of cinnamon EO and ZnO NPs were also determined using broth macrodilution method.  Moreover, the antibacterial properties of cinnamon EO and ZnO NPs were investigated in a liquid medium. The data were analyzed by SPSS 19 software, using one-way ANOVA and Tukey's post hoc tests.
Findings: The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of cinnamon EO were 16µl/ml and 64µl/ml, respectively. Furthermore, the MIC and MBC of ZnO NPs were 12.5mg/ml and 25mg/ml, respectively. The bacterial population significantly decreased with increasing the ZnO NPs and the cinnamon EO concentrations (p<0.05) and during cold storage, there were significant differences between the 2 strains.
Conclusion: Cinnamon essential oil and ZnO nanoparticles have strong antimicrobial effects against L. monocytogenes, so that the cinnamon essential oil shows bacteriostatic effects on Listeria, but ZnO nanoparticles show bactericidal effect.

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Backgrounds: Uropathogenic Escherichia coli is one of the most important etiological agents of UTI. The aim of this study was to investigate the antibacterial effects of zinc oxide nanoparticles (ZnONPs) on aminoglycoside-resistant E. coli isolates from patients with UTI.
Materials & Methods: After identifying E. coli strains in 100 out of 250 urine samples, antibiotic susceptibility was evaluated against six antibiotic classes (with emphasis on aminoglycosides) by disk diffusion method according to CLSI-2020 guidelines. The presence of aac (6')-Ie-aph (2'') gene in isolates was investigated by PCR. Antibacterial properties and minimum inhibitory concentration (MIC) of zinc oxide nanoparticles were evaluated by agar well diffusion and broth microdilution assays, respectively.
Findings: Among 100 E. coli isolates, the highest and lowest antibiotic resistance rates were observed against tetracycline (70%) and ofloxacin (10%), respectively. Of 30 gentamicin-resistant E. coli isolates, 17 (56.5%) isolates harbored the aac (6')-Ie-aph (2'') gene. In agar well diffusion assay, 22 (74%) gentamicin-resistant isolates were eliminated by zinc oxide nanoparticles at a concentration of 150 mg/L, while ZnONPs at 300 mg/L could eliminate all gentamicin-resistant isolates. Furthermore, ZnONPs could inhibit all bacteria at a concentration of 200 μg/mL (MIC₉₀ ≥ 100).
Conclusion: Spread of the aac(6')-Ie-aph(2'') gene could increase gentamicin resistance among E. coli strains causing UTI. Given the favorable antibacterial effects of zinc oxide nanoparticles in vitro, the clinical application of these nanoparticles in the treatment of UTIs caused by multidrug-resistant E. coli could be investigated in future studies.
 

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Aims: The present study intends to assess the toxicity of CuO and ZnO nanoparticles (NPs) at laboratory conditions on some pathogenic bacteria for the reared fish, as well as, a bioassay on rainbow trout.
Material & Methods: For this purpose, the sensitivity of them to the mentioned NPs with a reference antibiotic (florfenicol) was assayed through the well diffusion method, as well as, minimum inhibitory concentration (MIC) and minimum bacteriocidal concentration (MBC) were determined by microdilution technique. On the other hand, the lethal toxicity test has been accomplished to the calculation of median lethal concentration (LC50) on some rainbow trout (55.3±7.6 g) in static condition for the 96 consecutive hours. We use one-way ANOVA and Probit regression in order to data analysis.
Findings: Results show that NPs of copper oxide and zinc oxide could significantly inhibit the growth of Streptococcus iniae or kill it at 0.18 and 0.24 µg/ml and more, respectively. The comparison between LC50-96h quantities of CuO NP (107.4 µg/l) and ZnO NP (102.3 µg/l) indicated that the CuO NP has more toxic potential.
Conclusion: According to the laboratory findings, the susceptibility of S. iniae and L. garvieae to ZnO NP were close to florfenicol. The mortality in the fish species due to lethal toxicity would occur if the effective concentration of NPs on the bacterial pathogenic agents being used directly.

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Double layer ZnO/SnO2 thin film resistive gas sensors were fabricated by successive PVD of those oxides onto porcelain substrates. The metallic contacts were provided by electron beam evaporation of platinum onto substrates prior to deposition of the gas sensitive layers. Deposits were thermally annealed at different temperatures. It was shown that the activation energy of electrical conduction in the double layer depends on the annealing temperature. Higher annealing temperatures result in larger activation energies. The sensitivity of the double layer devices to ethanol vapor was measured and compared to that of single layer SnO2 sensors fabricated at similar conditions. It was shown for the first time that the gas sensitivity of ZnO/SnO2 thin film gas sensors can be adjusted by controlling parameters of the thermal annealing process.

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The effects of sodium chloride and Zn rates and sources on the growth and chemical composition of lowland rice (Oryza sativa L.) were studied using calcareous soil in a greenhouse experiment. The treatments comprised 5 levels of NaCl (0, 12.5, 25, 37.5 and 50 mmol kg-1 soil), three Zn rates (0, 5 and 10 mg kg-1 soil) and two Zn sources (ZnSO4, 2H2O and ZnEDTA). Applied salinity decreased shoot dry weight, leaf area and chloro-phyll concentration, whereas Zn supply significantly increased these growth parameters. However, the enhancing effect of soil Zn fertilization was more pronounced at lower NaCl levels than under higher salt stress, irrespective of Zn sources. Concentrations of Zn, P and K were significantly decreased and those of Na and Cl increased in NaCl-treated plants. Zn application markedly increased Zn concentration and decreased Na and Cl and P accumulation in shoots. Moreover, there was a significant difference between the two Zn sources to affect rice growth. Free proline increased but reducing sugars de-creased with an increase in the levels of substrate NaCl. However, Zn-untreated rice con-tained higher proline and reducing sugars than Zn-treated plants. Furthermore, an in-crease in proline was greater in the presence than in the absence of Zn and with ZnSO4 than with ZnEDTA. It is concluded that a decrease in soil osmotic potential, nutrient im-balance and excessive plant accumulation of Na and Cl in NaCl-treated plants caused growth suppression, whilst Zn supply decreased the suppressing effects of excess salt on rice growth. Therefore, it is recommended that for growing rice in saline soils that are low in available Zn, Zn should be supplied in a adequate quantities.

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Nitrogen use efficiency (NUE) is usually lower in paddy rice (Oryza sativa L.) than in upland crops. For this reason, any attempt to improve NUE through the use of different nitrogen (N) carriers, different rice cultivars, properly timed N application, the use of ni-trification and urease inhibitorsis of prime interest. Moreover, zinc (Zn) next to N seems to be the most important soil factor affecting rice growth. Although the response of rice N and Zn fertilization has been reported elsewhere, the authors are not aware of any such information for the calcareous paddy rice soils of Iran. Therefore, the present experiment was conducted to study the effects of varying sources and levels of N and Zn rate on the growth and N and Zn concentrations and uptake by rice. Treatments consisted of five N levels (0, 50, 100, 200, and 400 mg N kg-1soil), four N sources [urea (U), sulfur–coated urea (SCU), ammonium sulfate (AS), and ammonium chloride (AC)] and three Zn rates (0, 5, and 10 mg Zn kg-1 soil as zinc sulfate). The experiment was factorially arranged in a com-pletely randomized design with three replicates. The results showed that the highest top dry weight was obtained with SCU, and followed by AS, AC and U. Application of N up to 200 mg kg-1 as U, AS, and AC increased rice growth significantly. However, there was a consistent significant increase in shoot growth with the addition of SCU. In the present study, Zn fertilization had no significant effect on rice growth. The uptake and concentra-tion of N and Zn were increased by application of N and Zn. However, the highest Zn concentration and uptake were obtained with AC and SCU, respectively. Nitrogen and Zn addition generally increased leaf area and the maximum leaf area was obtained with SCU. Nitrogen yield efficiency (NYE) was reduced with increasing N rates (as U, AS, and AC) and increased up to 200 mg N kg-1 as SCU. Apparent N recovery (ANR) increased with increasing N up to 200 mg kg-1 as U, AS, and AC and declined thereafter. However, there was an increase in ANR with an increasing N level as SCU. On the other hand, N physiological efficiency (NPE) decreased with increasing N rates regardless of N sources. From the results reported here, it appears that 200 mg N kg-1 is the most appropriate N level and SCU appears to be the most efficient N source for lowland rice.

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This study aims to compare effects of sources levels of zinc on growth and carcass quality, some haematological and serological indices of juvenile beluga sturgeon, Huso huso (Linnaeus, 1758). A number of 315 juvenile beluga sturgeon (8.4±0.29) were fed in 21 500 lit fiberglass tanks (15 fish per tank) under 7 experimental diets including 1 control diet plus 6 diets containing zinc (mg per kg of diet) in two forms of mineral (zinc sulfate) (ZnSul₁₅, ZnSul_30, and ZnSul₆₀ treatments) and organic (chelated with methionine) (ZnMet_15, ZnMet₃₀, and ZnMet₆₀ treatments) with three replications per treatment for 12 weeks. The best values of final weight and feed conversion ratio were observed in the ZnMet₁₅ and ZnMet₆₀ treatments_. Red blood cells, hemoglobin, and hematocrit showed an incremental trend influenced by increased zinc supplement. Increased carcass protein in the ZnMet₃₀ treatment was significant compared to the control, ZnSul₁₅, and, ZnSul₃₀ treatments (P≤0.05). Reduced carcass lipid in the ZnSul₃₀ and ZnSul₆₀ treatments was significant compared to the other treatments (P≤0.05). Serum triglyceride and cholesterol decreased in the ZnMet treatments compared to the control treatment. Reduced serum glucose in the ZnMet₁₅ and ZnMet₆₀ treatments and also increased serum lysozyme in the ZnMet₃₀ and ZnMet₆₀ treatments were significant compared to the control treatment (P≤0.05). Results demonstrated that most of the indices had better performance in the ZnMet treatments comparted to the other treatments and are proposed as an optimal diet for juvenile beluga sturgeon.
 

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An experiment was conducted to evaluate the effectiveness of chemical and non-chemical molting methods as compared to conventional feed removal methods with respect to the physiological response and postmolt performance in Hy-line W36 laying hens. One hundred and eight 78-week-old hens were distributed among 27 groups of four birds and placed in cages so that the mean body weight of each cage was very similar. Three adjacent cages were considered as a replicate and 3 such replicates were assigned to each treatment. There were three treatments (molting procedures). Treatment 1 was continuous feed removal (CFR) and considered as the control. Hens on treatment 2 (T2) were fed finely ground delinted whole cottonseed as the sole feed ingredient and dietary vitamin and macro and microelement levels were maintained according to Hy-line W36 guideline specifications. Birds on treatment 3 (T3) received a layer diet containing 5,000 ppm Zn and fed at the rate of 50 g b-1 d-1. The results indicated that hens subjected to CFR, whole cotton seed and zinc supplemented diet went out of production on Day 6, Day 7 and Day 14, respectively. Continuous fasting and feeding whole cottonseed as molting programs resulted in significantly (P< 0.05) lower body weight and serum T3 concentrations but higher heterophil to lymphocyte (H:L) ratio and hematocrit, compared to the zinc method when measured on Day 7. Birds that received molt diet supplemented with zinc produced heavier eggs postmolt (P< 0.05) in comparison to other treatments but the egg production, egg mass and egg quality criteria were not different among the treatments.

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This study was carried out to obtain quantitative relationships between Zn in equilibrium solution and that retained by 20 calcareous soils. Soils were brought into equilibrium with varying solution concentrations of Zn, and the amounts removed from solution were used to check the fit to six adsorption isotherms, namely, Freundlich, Langmuir, Temkin, Gunary, two surface Langmuir and Adjusted Freundlich. Zinc sorption and desorption data showed hysteresis which indicates adsorption and desorption mechanisms not being the same. Fits of adsorption equations showed that Freundlich equation did not describe Zn sorption in most of the soils at low equilibrium concentrations, but after removal of the three first concentration points this equation showed a best fit to the data. The single surface Langmuir equation did not describe Zn sorption data, but a two surface Langmuir equation showed statistically significant fits to the data for some of the selected soils. Temkin equation described data only at low equilibrium concentrations.