Concentrations Of Ethylenediaminetetraacetic Acid Research Articles

Solar Photocatalytic Removal of Selenite, Selenate, and Selenocyanate Species

Selenium release into aqueous environment because of increased anthropogenic activities and its adverse effects onto human and animal health have initiated stringent selenium drinking water and wastewater discharge regulations. Though typically selenite (SeO32−) and selenate (SeO42−) account for most selenium species in selenium contaminated water bodies however selenocyanate (SeCN−) is another dominant selenium form in specific industrial effluents including those from petroleum refineries, mining, and power plants using fossil fuels. The present study investigated the potential of solar photocatalytic degradation (SPCD) process employing titanium dioxide (TiO2) as photocatalyst and ethylenediaminetetraacetic acid (EDTA) as a hole scavenging agent, for the removal of selenite, selenate, and selenocyanate species from aqueous phase. The experimental results indicated pH 4 to be the optimum for highest selenium removal. Furthermore, solar energized photocatalytic removal of selenite, selenate, and selenocyanate increased with an increase in both initial selenium and initial EDTA concentrations. Though selenite and selenate can be reduced directly to elemental selenium, selenocyanate is removed via a two steps process, i.e., SeCN‐complex destruction followed by stepwise oxidation to selenite/selenate and then reduction to elemental selenium. Furthermore modeling results for selenocyanate removal using the response surface methodology and Box‐Behnken design method are also presented. In general, solar photocatalysis is a promising technology that can successfully remove the aforementioned selenium species from aqueous phase with a careful adjustment of process variables.

Growth and characterization of EDTA assisted CBD-CdS

Chemical bath deposition of CdS (CBD-CdS) thin films with the assistance of a cationic surfactant, ethylenediamine tetraacetic acid (EDTA), is reported in this work. Also the EDTA treated CdS thin films are compared with that of conventional CBD-CdS. Fabricated thin, compact, uniform and adherent EDTA-treated CdS films show enhanced effective surface area and roughness compared to conventional CBD-CdS. The grazing incidence x-ray diffraction analysis shows all the fabricated CdS films are hexagonally crystallized. EDTA-treated CdS films show excellent photo activity compared to conventional CBD-CdS. The flat band potential (Vfb) value was found to be tunable with EDTA concentration.

Electrochemical Oxidation of EDTA in Nuclear Wastewater Using Platinum Supported on Activated Carbon Fibers.

A novel Pt/ACF (Pt supported on activated carbon fibers) electrode was successfully prepared with impregnation and electrodeposition method. Characterization of the electrodes indicated that the Pt/ACF electrode had a larger effective area and more active sites. Electrochemical degradation of ethylenediaminetetra-acetic acid (EDTA) in aqueous solution with Pt/ACF electrodes was investigated. The results showed that the 3% Pt/ACF electrode had a better effect on EDTA removal. The operational parameters influencing the electrochemical degradation of EDTA with 3% Pt/ACF electrode were optimized and the optimal removal of EDTA and chemical oxygen demand (COD) were 94% and 60% after 100 min on condition of the electrolyte concentration, initial concentration of EDTA, current density and initial value of pH were 0.1 mol/L, 300 mg/L, 40 mA/cm2 and 5.0, respectively. The degradation intermediates of EDTA in electrochemical oxidation with 3% Pt/ACF electrode were identified by gas chromatography-mass spectrum (GC-MS).

Facile synthesis of biphasic calcium phosphate microspheres with engineered surface topography for controlled delivery of drugs and proteins

Biphasic calcium phosphate (BCP) microspheres are of great interest due to their high stability and osteoinductive properties at specific compositions. However, the need for optimal performance at a unique composition limits their flexibility for tuning drug release by modulation of bulk properties and presents the question of engineering surface topography as an alternative. It is necessary to have a facile method to control surface topography at a defined bulk composition. Here, we have produced BCP microspheres with different surface topographies that have the capability to be used as tunable drug release systems. We synthesized calcium deficient hydroxyapatite (CDHA) microparticles by precipitating calcium and phosphate ions onto ethylenediaminetetraacetic acid (EDTA) templates. The morphology and surface topography of CDHA microparticles were controlled using process parameters, which governed nucleation and growth. These parameters included template concentration, heat rate, and stirring speed. Under low heat rate and static conditions, we could obtain spherical microparticles with long and short nanosheets on their surfaces at low and high EDTA concentrations, respectively. These nanostructured microspheres were subsequently crystallized by thermal treatment to produce EDTA-free BCP microspheres with intact morphology. These biocompatible BCP microspheres were highly effective in loading and prolonged release of both small molecule [dexamethasone (Dex)] and protein [bovine serum albumin (BSA)] models. This strategy has enabled us to control the surface topography of BCP microspheres at defined compositions and holds tremendous promise for drug delivery and tissue engineering applications.

Reclamation of EDTA by sodium tetraethylenepentamine-multi dithiocarbamate after soil washing process with EDTA

Ethylenediaminetetraaceticacid (EDTA) has been proven to be an efficient soil washing liquid to remove metal contaminants from soils. However, EDTA may cause secondary pollution due to its low biodegradability if it is not recycled or destroyed in the washing process. Thus, it is necessary to recycle and recover EDTA for sustainable use. In this paper, the extracting performance of fresh EDTA was firstly studied as a function of EDTA concentration, liquid/sediment (L/S) ratio and pH of the solution, and also extraction time. Then sodium tetraethylenepentamine-multi dithiocarbamate (TEPA-DTC), a heavy metals capturing agent, was synthesized on the base of the research of LIU-Lihua. Compared with Na2S and DDTC, TEPA-DTC shows strong chelating capacity, because it has functional groups of dithiocarbamate that could strongly chelate heavy metals and capture metal ions from Me-EDTA to form precipitates, allowing us to reclaim the EDTA during the process of soil washing. Three divalent heavy metals were investigated (Pb, Cd, and Cu). These three metals could almost precipitate completely with TEPA-DTC under the dosage of 300 mg/l, and EDTA was regenerated. The recovered EDTA was used again in three cycles of soil washing, and the amount of heavy metals extracted just slightly decreased each cycle.

EDTA chelating agent/seawater solution as enhanced oil recovery fluid for sandstone reservoirs

Experimental investigations and field applications showed noticeable increase in the oil recovery when low salinity water flooding is used. The mechanisms leading to the increase in oil recovery by low salinity water injection are debatable. Furthermore, low salinity water injection requires relatively huge amount of fresh water to dilute seawater which is not available in many areas around the world especially in the Arabian Gulf region. Using low salinity water as an enhanced oil recovery fluid is a costly process because it requires a lot of fresh water to dilute the seawater.In this paper we introduced EDTA (Ethylene Diamine Tetra Aceticacid)/seawater system for enhanced oil recovery in sandstone reservoirs. This fluid can be used in the secondary or tertiary flooding modes. EDTA/seawater enhanced oil recovery fluid utilizes high pH chelating agents at low concentrations prepared in seawater. Coreflooding experiments were performed using Berea sandstone cores at 100°C to investigate the effectiveness of EDTA/seawater EOR fluid system. In addition, Zeta potential measurements were performed for the EDTA/seawater and crushed Berea sandstone cores to examine the effect of EDTA/seawater on the rock surface charge. Also the effects of the chelating agent on the surface and interfacial tension (IFT) and oil recovery were evaluated. The effect of iron content on the sandstone rock charge was investigated using high iron content sandstone (Scioto sandstone). The effects of EDTA concentration and pH on oil recovery were also investigated. Also the effects of EDTA salt and chelating agent type on the oil recovery were investigated.The results of the coreflooding experiments showed that the EDTA/seawater fluid system was able to recover additional oil recovery up to 30% from the initial oil in place after seawater flooding when injected in the tertiary mode. The results of zeta potential revealed more negative values for the EDTA/seawater system more than the seawater and low salinity water, confirming that the rock wettability was altered towards a more water-wet condition due to the high negativity of the rock surface. The EDTA/seawater yielded low interfacial tension values with the crude oil used in the flooding experiments. Inductively coupled plasma (ICP) analysis for the coreflooding effluent samples showed increase in various cations concentration. The increase in cations concentrations confirmed the rock dissolution during the flooding process. EDTA chelating agent eliminated the iron effect on the surface charge in high iron content Scioto sandstone. Coreflooding experiments showed that EDTA should be used at concentrations higher than 5wt% to yield high oil recovery. Also EDTA should be used at pH higher than 12 to obtain high oil recovery. Sodium salt EDTA performed better than the ammonium salt EDTA in the oil recovery experiments. EDTA chelating agent was better than the HEDTA chelating agent in terms of oil recovery.Based on the experimental results, the possible recovery mechanisms when using EDTA/seawater system at pH 12.2 could be: IFT reduction, rock dissolution, and wettability alteration.

Risks of using EDTA as an agent for trace metals dosing in anaerobic digestion of olive mill solid waste

ABSTRACTLow concentrations of trace elements in many organic wastes recommend their supplementation in order to avoid potential limitations. Different chelating agents have been used to ensure an adequate trace metal pool in the soluble fraction, by forming dissolved complexes. Ethylenediaminetetraacetic acid (EDTA) is probably the most common, although several negative effects could be associated with its usage. Biomethane potential tests were performed using Olive Mill Solid Waste as the substrate, supplementing different combinations of Fe, Co, Ni, Ba, always under the presence of EDTA. Results show that Ni and Co slightly recovered biodegradability. However, Ba supplementation resulted in worsening the methane yield coefficient in all cases. High concentration of EDTA led to decrease in the activity of anaerobic digestion. High availability of EDTA induces the capture of trace metals like Co or Ni, key trace metals for anaerobic biomass activity. While supplementing trace metals, the addition of Ba and/or EDTA must be carefully considered.

Environmentally relevant concentrations of aminopolycarboxylate chelating agents mobilize Cd from humic acid

Although Cd is a pollutant of public health relevance, many dietary sources from which it can be absorbed into human tissues remain unknown. While it is well established that the biogeochemical cycle of Cd involves its complexation with environment-derived ligands (e.g., humic acids, HAs) and anthropogenic ones (e.g., chelating agents, CAs), the interaction of Cd with both of these ligands is less well understood. To gain insight, a HA–Cd complex was injected on a size-exclusion chromatography (SEC) column coupled on-line with a flame atomic absorption spectrometer (FAAS) using 10mmol/L Tris buffer (pH8.0) as the mobile phase. This approach allowed us to observe the intact HA–Cd complex and the retention behavior of Cd as a function of 2–20μmol/L concentrations of ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) or methylglycinediacetic acid (MGDA) that were added to the mobile phase. An increase of the retention time of Cd was indicative of a partial or complete abstraction of Cd from HA. Our results revealed that all CAs abstracted Cd from the HA–Cd complex at concentrations of 5μmol/L, while MGDA and DTPA were effective at 2μmol/L. The bioavailability of some of the on-column formed CA–Cd complexes explains the previously reported increased accumulation of Cd in periphyton in the ecosystem downstream of wastewater treatment plants. In addition, our results imply that the use of effluents which contain CAs and Cd for the irrigation of food crops can introduce Cd into the food supply and compromise food safety.

Microwave-assisted synthesis of NaYF4:Yb3+/Tm3+ upconversion particles with tailored morphology and phase for the design of UV/NIR-active NaYF4:Yb3+/Tm3+@TiO2 core@shell photocatalysts

Coupling of TiO2 with rare earth (RE) metal-based upconversion particles (UCPs) is a promising strategy to develop near-infrared (NIR)-driven TiO2-based photocatalysts. This, however, requires the controlled synthesis of bright NIR-to-UV UCPs with tailored morphology, size and crystalline phase. Herein, we report a rapid, efficient and reproducible co-precipitation/microwave (MW)-assisted hydrothermal method for the preparation of NaYF4:Yb3+/Tm3+ UCPs which allows tailoring the morphology (spherical nanoparticles, microrods) and crystalline phase (cubic, hexagonal) and hence the optical response of the resulting UCPs by simply varying the MW treatment time or ethylenediaminetetraacetic acid (EDTA) concentration. The EDTA concentration strongly affects the size of the primary UCPs during the co-precipitation step which plays a decisive role in dictating the final particle morphology in the subsequent MW-assisted hydrothermal step. Based on microscopic and XRD analyses, a model for the growth of UCPs with different morphologies has been proposed. Pure hexagonal microrods with strong upconversion (UC) photoluminescence (PL) in the UV (345 nm, 361 nm) and visible (450 nm, 475 nm) regions are obtained using MW treatment times of 30–60 min and EDTA/RE3+ molar ratios above 1.5. The UCPs@TiO2 core@shell composite photocatalysts prepared by coating anatase TiO2 on the surface of UCPs using a sol–gel method showed good photocatalytic activity under both ultraviolet (UV) and NIR light. This efficient and reproducible co-precipitation/MW-assisted approach may be considered as a step forward towards the efficient harvesting of sunlight for photochemical and photoelectrical applications based on TiO2.

A comparative evaluation of the effect of 8% and 17% ethylenediaminetetraacetic acid exposure for 1 min and 10 min on the fracture resistance of endodontically treated roots: An in vitro study.

Objective:The objective of this study was to evaluate the effect of 8% and 17% ethylenediaminetetraacetic acid (EDTA) exposure for 1 min and 10 min on the fracture resistance of endodontically treated roots.Methodology:Sixty human single-rooted teeth were decoronated and divided into six groups (n = 10). Canal preparation was carried out except in negative control group, using the ProTaper rotary file system. Final irrigation was performed using distilled water, 17% EDTA for 1 min and 10 min, 8% EDTA for 1 min and 10 min. Thereafter, roots were obturated with ProTaper F3 Gutta-percha points and AH Plus sealer using a single-cone technique. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with one-way analysis of variance and post hoc Tukey test.Results:Analysis of results showed that the unprepared roots showed the highest fracture resistance and roots irrigated with 17% EDTA for 10 min showed the lowest fracture resistance. The mean fracture resistance of unprepared roots, roots irrigated with 8% EDTA for 10 min and 17% EDTA for 1 min was significantly higher than roots irrigated with 8% EDTA for 1 min, 17% EDTA for 10 min and distilled water.Conclusion:From a clinical viewpoint, if EDTA has to be used, it is safer to use higher concentration for a shorter application time or a low concentration with a longer application time. Prolonged use of high concentrations of EDTA might increase the risk of root fracture.

Effect of final irrigation procedures on fracture resistance of root filled teeth: an exvivo study.

To evaluate the effect of chlorhexidine (CHX) on fracture resistance of roots treated with different concentrations of ethylenediaminetetraacetic acid (EDTA). One hundred and twenty intact single-rooted premolar teeth were sectioned below the cementum-enamel junction to standardize the length of the teeth to 12mm. The canals of one hundred specimens were instrumented with ProTaper Universal rotary instruments up to size F4 and were randomly divided into five groups (n=20) according to the final irrigating solutions: Group 1: distilled water (DW); Group 2: 5% EDTA and 2.5% NaOCl; Group 3: 17% EDTA and 2.5% NaOCl; Group 4: 5% EDTA, 2.5% NaOCl, DW and 2% CHX; Group 5: 17% EDTA and 2.5% NaOCl, DW and 2% CHX. Root canals were filled with gutta-percha and epoxy resin-based root canal sealer using a single-cone technique. Twenty teeth served as negative controls and were not instrumented nor root filled (Group 6). All specimens were embedded in self-curing acrylic resin and loaded vertically at 0.5mmmin-1 until fracture occurred. The data were evaluated statistically using one-way anova test followed by Holm-Sidak's multiple comparison test (P<0.05). Group 1 (only DW) had the lowest vertical fracture strength, followed by Group 3 (17% EDTA and 2.5% NaOCl; P<0.05). Group 6 (negative control group) had the highest fracture resistance. Final irrigation with CHX following irrigation with 17% EDTA or 5% EDTA and 2.5% NaOCl (groups 4 and 5) significantly increased the fracture resistance of roots (P<0.05). However, the difference between Group 4 and Group 5 was not significant (P>0.05). Intracanal CHX rinse of EDTA/NaOCl-treated root dentine enhanced the fracture resistance of roots filled with AH Plus.

Growth and properties of cubic SnS films prepared by chemical bath deposition using EDTA as the complexing agent

Recently, thin films of cubic SnS emerges as a promising solar cell absorber layer owing to its suitable optical and electrical properties. In this paper, we report the growth of cubic SnS thin films by a chemical bath deposition technique using ethylene diamine tetra-acetic acid (EDTA) as the complexing agent. Optimization of EDTA concentration has been carried out to increase the film thickness and to obtain compact and uniform cubic SnS films with good grain size. SnS films with a thickness in the range 500− 620 nm could be obtained with increasing the EDTA concentration in the solution for a deposition time of 6 h. The X-ray diffraction analysis of these films revealed the presence of cubic SnS with (222) and (400) as the preferred orientations. The lattice parameter of these films is found to be a = 1.158 nm and their crystallite size increases from 46 nm to 60 nm with increase in the EDTA concentration from 0.075 M to 0.125 M. Raman spectroscopy analysis revealed the presence of a minor SnS2 secondary phase in these films. X-ray photoelectron spectroscopy analysis revealed that Sn and S exhibit oxidation states of +2 and −2, respectively in these films. Scanning electron microscopic studies showed that the grain size first increased with increasing EDTA concentration from 0.075 M to 0.10 M and then decreased when the EDTA concentration is further increased to 0.125 M in the solution. The films deposited with an EDTA concentration of 0.10 M are compact and uniform with an average grain size of ∼1 μm. The direct optical band gap of these films, estimated from their spectral transmittance (Tλ) and reflectance (Rλ) data, is found to increase from 1.67 eV to 1.73 eV with increase in the EDTA concentration from 0.075 M to 0.125 M in the solution. Hall Effect measurements showed that the films are p-type in nature. The films deposited with 0.10 M EDTA concentration exhibited higher hole mobility of 28.6 cm2 V−1 s1, resistivity of 1.53 × 105 Ω cm and carrier concentration of 2.86 × 1012 cm−3. The above properties suggest that the films deposited from solution with 0.10 M EDTA concentration could be useful as solar cell absorber layer to obtain reasonable device efficiency.

Aseptic hydroponics to assess rhamnolipid-Cd and rhamnolipid-Zn bioavailability for sunflower (Helianthus annuus): a phytoextraction mechanism study.

The availability of cadmium (Cd) and zinc (Zn) to sunflower (Helianthus annuus) was investigated in rhamnolipid- and ethylenediaminetetraacetic acid (EDTA)-buffered solutions in order to evaluate the influence of aqueous speciation of the metals on their uptake by the plant, in relation to predictions of uptake by the free ion activity model (FIAM). Free metal ion activity was estimated using the chemical equilibrium program MINTEQ or measured by Donnan dialysis. The uptake of Cd followed the FIAM for the EDTA-buffered solution at EDTA concentrations below 0.4μM; for the rhamnolipid-buffered solution, the uptake of both metals in roots was not markedly affected by increasing rhamnolipid concentrations in solution. This suggests rhamnolipid enhanced metal accumulation in plant roots (per unit free metal in solution) possibly through formation and uptake of lipophilic complexes. The addition of normal Ca concentrations (low millimetre range) to the rhamnolipid uptake solutions reduced Cd accumulation in shoots by inhibiting Cd translocation, whereas it significantly increased Zn accumulation in shoots. This study confirms that although rhamnolipid could enhance accumulation of Cd in plants roots at low Ca supply, it is not suitable for Cd phytoextraction in contaminated soil environments where Ca concentrations in soil solution are orders of magnitude greater than those of Cd.

Development of a Spectrophotometric Biphasic Assay for the Estimation of mPEG-maleimide in Thiol PEGylation Reaction Mixtures

Methoxy(polyethylene glycol)-maleimide (mPEG-mal) is a PEG derivative used for thiol PEGylation of protein molecules and finds application in drug delivery studies. The maleimide group undergoes degradation in aqueous media, resulting in the difficult quantitative analysis of mPEG-mal. Routinely employed methods for separation and estimation of mPEG-mal include tedious chromatographic methods like ion exchange, high-performance liquid chromatography with refractive index detector and techniques like mass spectrometry and proton nuclear magnetic resonance. We present a direct and reproducible spectrophotometric method to quantify free and protein bound mPEG-mal in thiol PEGylation reaction mixtures. This method is based on the partitioning of a PEG bound chromophore between an aqueous ammonium isoferrothiocyanate phase to a chloroform phase in the presence of mPEG-mal. Several important parameters influencing the partitioning and stability of the chromophore, volume ratios of liquid phases, ethylenediaminetetraacetic acid concentration in the reaction mixture, mixing time, and chlorinated solvents used for partitioning have been studied.

Assessing bioavailability levels of metals in effluent-affected rivers: effect of Fe(III) and chelating agents on the distribution of metal speciation.

To assess the effects of Fe(III) and anthropogenic ligands on the bioavailability of Ni, Cu, Zn, and Pb, concentrations of bioavailable metals were measured by the DGT (diffusive gradients in thin films) method in some urban rivers, and were compared with concentrations calculated by a chemical equilibrium model (WHAM 7.0). Assuming that dissolved Fe(III) (<0.45 μm membrane filtered) was in equilibrium with colloidal iron oxide, the WHAM 7.0 model estimated that bioavailable concentrations of Ni, Cu, and Zn were slightly higher than the corresponding values estimated assuming that dissolved Fe(III) was absent. In contrast, lower levels of free Pb were predicted by the WHAM 7.0 model when dissolved Fe(III) was included. Estimates showed that most of the dissolved Pb was present as colloidal iron-Pb complex. Ethylene-diamine-tetra-acetic acid (EDTA) concentrations at sampling sites were predicted from the relationship between EDTA and the calculated bioavailable concentration of Zn. When both colloidal iron and predicted EDTA concentrations were included in the WHAM 7.0 calculations, dissolved metals showed a strong tendency to form EDTA complexes, in the order Ni > Cu > Zn > Pb. With the inclusion of EDTA, bioavailable concentrations of Ni, Cu, and Zn predicted by WHAM 7.0 were different from those predicted considering only humic substances and colloidal iron.

English

The effects of ethylenediaminetetra-acetic acid (EDTA) on germination, length of stem, area of leaf, fresh weight, level of lipid per oxidation, alkaline phosphatase, acid phosphatase, super oxide dismutase (SOD) and catalase in the roots of cadmium (Cd) treated maize (Zea mays L) and cowpea (Vigna unguiculata L) seedlings after 7 and 21 days of germination were determined in this study. The results obtained, indicate that at the end of 7 and 21 days of exposure to Cd, percentage germination of the seeds were not significantly different in both control and test soil (p&gt;0.05). Morphological parameters (area of leaf, length of stem and fresh weight) were significantly reduced by Cd after 7 and 21 days. The supplementation of the soil sample with EDTA (0.5 mM or 1.0 mM) reversed the effect of Cd on these parameters as it significantly increased length of stems, area of leaf and plant fresh weight. There was a significant decrease in root acid phosphatase, root alkaline phosphatase, super-oxide dismutase (SOD) and catalase activity in both plant species. Both used doses of EDTA to ameliorate the above biochemical parameters. Increased level of root lipid peroxidation in Cd treated maize and cowpea seedlings was observed after 7 and 21 days of germination. Albeit, the level of lipid peroxidation in the root of Cd treated maize was significantly higher than that of cowpea, an indication that cowpea may be more tolerant than maize to Cd toxicity. The treatment of plant with, concentrations of EDTA (0.5 and 1.0 mM) failed to decrease the Cd induced, but increased the level of root lipid peroxidation. These results indicate that EDTA (0.5 mM and 1.0 mM) could be used for the treatment of Cd toxicity in plants; although, EDTA did not totally protect cowpea seedling from oxidative stress. Key words: Heavy metal, phytoremediation.

Preparation and characterization of MgS thin films using spray pyrolysis technique

MgS thin films have been successfully prepared using low cost spray pyrolysis technique. Magnesium sulphate (MgSO4·7H2O) was the source of Mg2+ while sodium thiosulphate served as the source of S2−. Ethylene diamine tetra acetic acid (EDTA) was used to slow down the reaction rate. The aim of this study is to establish the optimized experimental conditions needed to grown MgS thin films. X ray diffraction and atomic force microscopy (AFM) techniques are used to examine the effect of the concentration of the agent complexant EDTA used to grow MgS thin films. The structural analysis shows the formation of MgS thin film with preferential orientation (200) for sprayed solution containing EDTA. It is revealed also the diffraction peaks belonging to the MgSO4 thin films crystallizing in orthorhombic structure. All samples were well adhered to the substrate as revealed from AFM images. The optical properties of MgS thin films were investigated using spectrophotometric measurements in the wavelength range 250–2500 nm. These films, because of their low reflectance and high transmittance in the infrared regions, are suitable for coatings on different types of solar collectors.

In Vitro Mean Red Blood Cell Volume Change Induced by Diode Pump Solid State Low-Level Laser of 405 nm.

Objective: This study was conducted to investigate the effects of low-level laser (LLL) doses on human red blood cell volume. The effects of exposure to a diode pump solid state (DPSS) (λ = 405 nm) laser were observed. Background data: The response of human blood to LLL irradiation gives important information about the mechanism of interaction of laser light with living organisms. Materials and methods Blood samples were collected into ethylenediaminetetraacetic acid (EDTA)-containing tubes, and each sample was divided into two equal aliquots, one to serve as control and the other for irradiation. The aliquot was subjected to laser irradiation for 20, 30, 40, or 50 min at a fixed power density of 0.03 W/cm2. Mean cell volume (MCV) and red blood cell (RBC) counts were measured immediately after irradiation using a computerized hemtoanalyzer. Results: Significant decrease in RBC volume (p < 0.05, p < 0.0001, p < 0.0001, and p < 0.05, respectively) was induced with variation in laser doses.The highest response was observed with an exposure time of 40 min. This result was reproduced in RBCs suspended in a buffered NaCl solution. In contrast to this finding, laser-induced RBC volume change was completely abolished by suspending RBCs in a solution containing a higher concentration of EDTA. Conclusions: It was suggested that LLL can reduce RBC volume possibly because of the increased free intracellular Ca+2 concentrations, which activate Ca+2-dependent K+ channels with consequent K+ ion efflux and cell shrinkage.

Studies on fecundity and some physiological features for the ovaries of Nile Tilapia, Oreochromis niloticus treated with different concentrations of Ethylenediaminetetraacetic Acid (EDTA).

Studies on fecundity and some physiological features for the ovaries of Nile Tilapia, Oreochromis niloticus treated with different concentrations of Ethylenediaminetetraacetic Acid (EDTA).

Effect of ethylene diamine tetra acetic acid chelator in the presence of chromium on growth and some physiological characteristics of sunflower.

Chromium is a heavy metal toxic for plants that due extensive industrial applications over the last decade, has become a serious environmental pollution. On the other hand, chelator dissolution and absorption of metal by the plant increase and their use in phytoremediation is important. The aim of this study was to evaluate the effect of different concentrations of chromium and ethylene diamine tetra acetic acid (EDTA) chelator on sunflower (Heliantus annuus L.) through the study of growth parameters, chlorophyll, and soluble sugar amounts and Cr accumulation in plants under hydroponic culture. In order to plant sunflower were treated with different concentrations of Cr (1, 2, 4 and 6 ppm) and EDTA (0, 1 and 3 mg/L) in the medium Hoagland. The results showed that the use of chromium reduced the length of shoots and roots, and chlorophyll, while it increased soluble sugars. Addition of EDTA to the metal increased the shoot and root length and chlorophyll content while it reduced soluble sugars. According to the results, the use of chromium heavy metal in medium increased the amount of it in shoot and root. EDTA application, particularly with higher levels of chromium led to its accumulation in shoot and root. This research suggested positive role of application of EDTA in the presence of chromium heavy metal in increasing the power of phytoremediation of sunflower.