Ethylenediaminetetraacetic Acid Solution Research Articles

Determination of Aminophosphonate Herbicides in Glutamate Loaded Spice Mix by LC-IDMS and Method Extension to Other Food Matrices

The accumulation of organophosphorus type herbicides has been observed worldwide in the environment (i.e. soil, water), together with their appearance in foods of plant origin. This paper reports a new liquid chromatography–isotope dilution–tandem mass spectrometric method (LC-IDMS) for the analysis of glufosinate (GLUF), glyphosate (GLY) and its main metabolite, aminomethylphosphonic acid (AMPA), in challenging food samples. Sample preparation is based on aqueous extraction with ethylenediaminetetraacetic acid solution, followed by solid-phase extraction (SPE) on mixed-mode cation exchange cartridges to remove matrix constituents before derivatization with 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl). Derivatized samples were cleaned up on hydrophilic modified polymeric SPE cartridge. This two-step SPE supported sample preparation approach, and the LC-IDMS separation carried out in negative ionization mode resulted in fit-for-purpose recovery (81–118%) and precision (4–18%) in the validation of glutamate loaded spice mix, mushroom, maize and cherry samples. Amino acid content influencing FMOC derivatization efficiency was estimated with a HILIC-MS/MS setup. Multiple reaction monitoring (MRM) was assisted with high-resolution (QTOF) accurate mass data on the FMOC-derivatized GLUF, GLY and AMPA standards. The limit of quantification (LOQ) was 0.005 mg/kg for all the three analytes. The method was successfully applied on quality control samples (oat and arugula) with fit-for-purpose accuracy (99–120%) and on other nineteen real samples, where GLY and AMPA were detected in the range between 0.005 and 0.069 mg/kg.

Recycling of zinc and lead from electric arc furnace dust by selective leaching with EDTA

ABSTRACT Electric Arc Furnace Dust (EAFD) is a potential source of contamination, primarily by the non- ferrous metals as it may contain (Zn, Pb). It is known that steel processing companies make efforts to reuse EAFD, however, today, the implementation of the most common hydrometallurgical methods is considered to be harmful and corrosive. In that sense, a more ecological and efficient technique for the management of this industrial waste is proposed here. The technique consists in the use of an organic solution of ethylenediaminetetraacetic acid (EDTA) at moderate conditions (room temperature, 0.5 M maximum concentration and 2 h of operation) for zinc and lead extraction. To leach metals using EDTA at pH 3 and 6 is possible and favourable. The presence of ZnFe2O4 did not allow leaching of the total zinc present in EAFD, while the rapid dissolution of PbO allowed more than 95% lead extraction.

Structural, morphological and optical characterization of chemically deposited Cu2O/PbS thin films

Cu2O/PbS core-shell thin films were synthesized by a chemical bath deposition technique using a reactive mixture containing copper nitrate, lead nitrate, ethylenediaminetetraacetic acid, tetraethyl amine and ammonia solution. Their structural and optical properties are reported in this work. For the elemental composition estimation, Rutherford backscattering spectroscopy (RBS) was performed. From the proton induced scan on the substrate containing the films, all the elements that make up the films were extracted as Cu (34.86%), Pb (1.69%), S (42.31%) and O (65.15%). This is an indication that Cu2O-PbS quaternary thin films were actually deposited on the substrate. The X-ray diffraction analysis showed the formation of multiple peaks indicating that the films possess polycrystalline structure. The scanning electron micrographs of the films depicted particles of different sizes scattered across the film surface. The absorbance, transmittance, absorption coefficient, band gap and extinction coefficient were modified by thermal annealing. Absorbance varies from 1.175 to 1.35 for as-grown, 1.475 to 1.50 for annealed at 150 oC and 1.65 to 2.00 for annealed at 200 oC. The percentage transmittance of 6.75 % was obtained for as-grown sample while those of the annealed samples are 6.0 % and 5.0 % at 150 oC and 200 oC respectively. Maximum absorption coefficient values are 3.48 x 106 m -1 , 3.68 x 106 m -1 and 4.60 x 106 m -1 for As-grown, annealed at 150 oC and 200 oC respectively. The band gap energy value is found to increase from 3.50 eV to 4.00 eV as a result of the increase in annealing temperature from 150 oC – 200 oC. Extinction coefficient values generally varies from 0.75 to 2.70 for as-grown, 0.80 to 2.85 for annealed at 150oC and 0.85 to 3.00 for annealed at 200oC. Based on the wide band gap exhibited by the films, it can be concluded that the films are suitable as window materials in the fabrication of solar cell devices.

A pH-Responsive Liquid Crystal Hydrogel Actuator with Calcium-Induced Reprogrammable Shape Fixing

Soft polymer actuators have myriad applications and have therefore gained considerable attention in recent years. However, it remains challenging to prepare soft actuators with predefined shapes. Here, a bilayer polymer actuator with a (re)programmable shape is prepared from a microporous anisotropic polypropylene scaffold and a thin, pH-responsive liquid crystalline network (LCN) layer. The hydrogen bonds between dimerized benzoic acid derivatives in the LCN can be disrupted by an alkaline treatment, resulting in a pH-responsive LCN hydrogel layer. The pH-responsive actuation is governed by both the anisotropic mechanical properties of the scaffold and the cross-link density of the LCN hydrogel. Ca2+ ions can be used to chemically cross-link the actuator resulting in an initial programmed shape. The shape fixing can be reversed by removing the Ca2+ ions with an ethylenediaminetetraacetic acid (EDTA) solution. The shape fixing can be performed locally, resulting in pH-responsive actuators with three-dimensional initial configurations of choice.

Human Treated Dentin Matrix Hydrogel as a Drug Delivery Scaffold for Regenerative Endodontics.

The objective of the current study was to develop a human treated dentin matrix (hTDM) hydrogel for use as a scaffold to allow the controlled release of an antimicrobial agent for regenerative endodontics. Human extracted teeth were treated via chemical demineralization using ethylene diamine tetra-acetic acid solution to produce hTDM powder. Fourier transform infrared spectroscopy (FTIR) was conducted to determine the functional groups of hTDM, scanning electron microscopy (SEM) was used to define the morphology/particle size of hTDM, and energy dispersive X-ray analysis was performed to identify the superficial apatite groups. Prepared hTDM powder was added to the amoxicillin-clavulanate mixture with a mass ratio of 1:1. Then, the combination was dripped into a 5% (w/v) calcium chloride solution. Antibiotic release profiles were evaluated for 14 days via high performance liquid chromatography (HPLC). Hydrogel degradation properties were studied for 14 days using 10 mL of phosphate buffered saline (PBS). Encapsulation efficiency was determined by HPLC, while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of amoxicillin-clavulanate were determined against Enterococcus faecalis (E. faecalis). The antibacterial activity of amoxicillin-clavulanate against E. faecalis was investigated for 14 days via agar diffusion test. Statistical analysis was performed with the Shapiro-Wilk test (P=0.05). hTDM showed statistically a significant difference for percentage weight change (P=0.1). The encapsulation efficiencies for hTDM hydrogel with antibiotic and hydrogel with antibiotic was 96.08%±0.02 and 94.62%±0.11, respectively. MIC and MBC values of amoxicillin-clavulanate against E. faecalis were 2.4 µg/mL and 9.6 µg/mL, respectively. The antibacterial activity of antibiotic loaded hTDM hydrogels was significantly greater than loaded hydrogels alone by 31% after 4 days and 100% at 14 days, respectively (P≤0.001). This in vitro study showed antibiotic-loaded injectable hTDM hydrogel could be an alternative system to transfer antibiotic-based intracanal medicaments for use in regenerative endodontics.

Comparative evaluation of decalcifying agents for dissolution of pulp stones: An in vitro study.

Background:Despite constant advances in science, obscurity remains in the efficient removal of pulp stones to aid in successful root canal treatment. In this context, chemical means of dissolving pulp stones were explored.Aim:The aim of this study is to evaluate and to compare the efficacy of decalcifying agents on the dissolution of pulp stones.Materials and Methods:The study was divided into two groups for pulp stone analysis (21 samples) and dentin analysis (54 samples). Twenty-one pulp stones from patients aged 18–70 who underwent root canal treatment were collected and divided into three subgroups (n = 7) randomly. They were subjected to chemical treatment in a labeled glass container with 5 ml of the respective chemical agents, such as 17% ethylenediaminetetraacetic acid solution (positive control), no treatment (negative control), and newly developed Physiological Simulated Decalcifying Agent (PSDA). At the end of the study period (24 h), the samples were removed, rinsed with deionized water, and subjected to physical analysis, scanning electron microscopy (SEM), and Energy –dispersive X-ray spectroscopy (EDS) analysis. Under dentin analysis, 54 maxillary premolars scheduled for orthodontic extraction without caries or extensive restorations were selected, following which 2-mm thick transverse dentinal sections at the cementoenamel junction level were obtained and randomly divided into two groups for SEM (n = 21) and microhardness analysis (n = 33). The samples were subjected to respective chemical treatment groups similar to pulp stones for 24 h and analyzed using SEM, EDS, and microhardness analysis.Results:Postchemical treatment with the newly developed decalcifying solution, the pulp stones showed the absence of nodular crystallites and surface softening under SEM and a decrease in the calcium level under EDS analysis. Concerning the microhardness of dentin, no significant changes could be observed.Conclusion:The newly explored PSDA was found to be efficacious in the decalcification of pulp stones at a clinically relevant time of 24 h, without significantly affecting the structural integrity and the hardness values of dentin.

Preparation of Polymer Microemulsion Flocculant and its Application in Drilling Fluid

Organic macromolecular flocculants have broad application prospects in drilling fluid systems due to their strong adsorption capacity and many other advantages. At present, polyacrylamide polymer is mostly used in drilling fluid, which is difficult to dissolve, time-consuming and laborious. In this regard, this study uses acrylamide and acrylic acid as monomers, mixes acrylic acid with potassium hydroxide, adds disodium ethylenediaminetetraacetic acid solution after adsorption and filtration, and then adds acrylamide to prepare a mixed solution, using H2O2 as the initiator, polymerization reaction in microemulsion to prepare macromolecular microemulsion flocculant. It can be quickly dissolved by adding a small amount of film release agent OP-10 during application. Through the laboratory evaluation experiment of drilling fluid, it has stronger flocculation inhibition effect on the slurry formation and drill cuttings. It has strong ability to contain drill cuttings and anti-drill cuttings pollution. It is easy to absorb water to expand and can be dispersed and collapsed. The drilling roller recovery rate is high. The field application was good when carried out in Shunbei 5-14H.

Separable double-layered microneedle-based transdermal codelivery of DOX and LPS for synergistic immunochemotherapy of a subcutaneous glioma tumor

An efficient and patient-friendly process for administering immunochemotherapy is achieved through microneedle (MN)-mediated drug delivery into the dermal interstitium across the stratum corneum. Herein, we designed an interpenetrating polymer network (IPN) hydrogel to fabricate separable MNs for transdermal codelivery of lipopolysaccharide (LPS) and doxorubicin (DOX) for a synergistic immunochemotherapeutic outcome. The MN arrays were fabricated from IPN hydrogel which was prepared via sequential photoionic crosslinking of sodium alginate and sulfobetaine methacrylate using N, N’-methylenebisacrylamide and Ca2+ ion for chemical and ionic crosslinking, respectively. Tensile and compression tests revealed that the mechanical strength of the IPN hydrogel increased significantly and the MN array enabled skin penetration. The separable backbone of the MNs was prepared using a disulfide-crosslinked IPN hydrogel that was easily removed by disulfide bond cleavage with 1,4-dithiothreitol and ethylenediaminetetraacetic acid solution, whereas the dual drug-loaded MN patch was left in the skin to allow steady drug release. In vitro drug release tests demonstrated that the MN array allowed the timely release of drugs due to the hydrogel's rapid degradation. The IC50 value of DOX@MNs (1.088 µg/ml) against the CT-2A-Luc cell line indicated that the drug loaded onto the MNs was more than sufficient to kill cancer cells. Moreover, in vivo tumor suppression experiment on glioma-bearing C57BL/6 mice confirmed that the dual drug-loaded MNs (LPS/DOX@MNs) led to excellent upregulation of immune response and tumor inhibition, signifying its synergistic immunochemotherapeutic effects. Thus, the concept of MN-mediated combined immunochemotherapy provides localized sustained delivery and is a promising new treatment method for obtaining efficient synergistic therapeutic values.

Optical fiber mercury biosensor based on immobilized urease and bromothymol blue onto the alginate-chitosan membrane in the flow-system

An optical fiber biosensor has been developed for the detection of mercury ion based on inhibition of urease immobilized onto alginate–chitosan membrane, coupled with bromothymol blue (BTB) in the flow system. To get a good performance of the biosensor toward Hg(II) ion detection, the experimental parameters of the biosensor were optimized. Here, the maximum wavelength was detected at 580 nm, with the optimum response at pH of 6. The calibration curve had a dynamic working range at 10 to 500 μg/L of Hg(II) ion with a detection limit of 12.1 μg/L biosensor has been performed by the addition of 1 mM ethylenediaminetetraacetic acid (EDTA) solution, in which five-time cycles have been achieved with the inhibition decrease to 9.94% from the original biosensor response. Applying the biosensor to the real samples showed conformity of results with the reference method, cold vapor atomic absorption spectrometry (CV-AAS). Therefore, this biosensor can be used as a method for routine analysis in the determination of Hg(II) concentration in an aqueous sample.

Effect of aspirin to intentionally induce leaky gut on performance, inflammation, and carcass characteristics of feedlot cattle

The negative impacts of stress on gastrointestinal tract (GIT) barrier function can result in compromised animal growth and health. Aspirin is known to cause mucosal injury leading to increased gut permeability and tight junction damage and can be used as a model to study leaky gut in cattle. The objective of this study was to determine the long-term impact of aspirin-induced chronic leaky gut on cattle growth and carcass attributes. Two treatments were evaluated in two studies: control (no aspirin) or 0.25% of the diet dry matter (DM) aspirin fed daily. Diets consisted of 50% corn, 24% dried distillers grains, 20% corn silage, and 6% supplement on a DM basis. In experiment 1, sixteen Angus × Simmental heifers, allotted by body weight (BW) and breed composition, were fed diets for 154 d. On day 155, heifers were dosed with 1 liter of a 180-mM Cr-ethylenediaminetetraacetic acid solution using an esophageal tube and had urine collected every 1.5 to 3 h for 48 h for analysis of Cr as a measure of gut leakiness. In experiment 2, ninety-six Simmental × Angus steers (355.0 ± 14.8 kg) were allotted by BW and breed composition and fed treatment diets for 159 d. Weight was recorded monthly and serum was collected on day 159 and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6 (IL-6), serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase (AST). Data were analyzed using the MIXED procedure of SAS. Heifers fed 0.25% aspirin in experiment 1 excreted more Cr into urine compared with heifers not fed aspirin (overall treatment effect, P = 0.01). In experiment 2, aspirin tended to increase serum LBP (P = 0.06) but had no effect on concentrations of IL-6, haptoglobin, SAA, or AST (P ≥ 0.25). Aspirin tended to decrease average daily gain (P = 0.10), decreased hot carcass weight and rib-eye area (P ≤ 0.05), and increased fat thickness, marbling score, and yield grade (P ≤ 0.02). Aspirin tended to increase kidney, pelvic, and heart fat percentage (P = 0.10) and had no effect on liver abscesses (P ≥ 0.80). This study indicates that leaky gut induced by long-term administration of aspirin has negative impacts on feedlot performance and carcass composition. The negative impact of aspirin-induced leaky gut on animal performance suggests that chronic leaky gut caused by other factors (subacute acidosis, stress) may be a significant problem for the feedlot industry.

Bone-Adhesive Hydrogels Based on Dual Crosslinked Poly(2-oxazoline)s.

The development of bone glues based on bone-adhesive hydrogels to allow for facile bone fracture fixation remains a major challenge. Herein, dual crosslinked hydrogels that combine tunable stiffness, ductility, and self-healing capacity are successfully synthesized. The resulting double network hydrogel is formed by chemical crosslinking of N-hydroxysuccinimide-functionalized poly(2-oxazoline)s(POx-NHS)"?> with amine-functionalized poly(2-oxazoline)s, and physical crosslinking of alendronate-functionalized poly(2-oxazoline)s (POx-Ale) with calcium ions in solution. The use of an excess of alendronate-functionalized POx-Ale polymers also ensures affinity toward calcium cations in the mineral phase of bone, thereby rendering these hydrogels adhesive to bone. The mechanical and bone-adhesive properties of these novel hydrogels are superior to commercially available fibrin sealants. Moreover, hydrogels retain their bone-adhesive properties under wet conditions. Although the dual crosslinked hydrogels swell considerably, they are stable upon immersion in phosphate-buffered saline (up to 12 d) and even in ethylenediaminetetraacetic acid solution. The enhanced mechanical and bone-adhesive properties of these hydrogels, as well as their in vitro stability, indicate that they have much application potential as bone-adhesive glues.

Determination of Folic Acid in Multivitamin Preparations by Reversed Phase HPLC

A great variety of components in multivitamin preparations containing folic acid, and a variety of test methods and conditions of folic acid determination proposed by manufacturers, require alignment of test procedures for products with similar composition.The aim of the study was to compare the results of experimental verification of folic acid determination procedures which use reversed phase high-performance liquid chromatography (RP HPLC) with isocratic elution mode. Materials and methods: The Agilent 1260 Infinity II LC system with a diode array detector (280 nm), isocratic elution mode, C8- and C18-bonded silica gel chromatographic columns, model mixtures containing folic acid, cyanocobalamin, ferrous sulfate, and potassium iodide, were used in the study.Results: The lowest relative standard deviation of the folic acid peak area (RSD=0.09%), and the lowest asymmetry factor (As=1.04) for folic acid were observed for the model mixture “ferrous sulfate+folic acid+cyanocobalamin” and the following test conditions. Column: 250×4.0 mm, silica gel for chromatography, octylsilyl (C8), endcapped; mobile phase: methanol‒phosphate buffer (12:88), pH 6.6; column temperature: 25ºС. The study demonstrated the feasibility of using these conditions for determination of pteroic acid impurity with simultaneous precipitation of interfering ferrous ions, using ethylenediaminetetraacetic acid solution, pH 9.5, as a solvent.Conclusions: RP HPLC can be recommended as an optimal aligned test procedure for determination of folic acid in combination products. It is recommended to use a solution containing folic and pteroic acids for system suitability testing.

Phosphorylated PAMAM dendrimers: an analog of dentin non-collagenous proteins, enhancing the osteo/odontogenic differentiation of dental pulp stem cells.

Polyamidoamine (PAMAM) dendrimers have well-defined structures, with monodispersity and easily modified surface groups, and they have broad applications in biomedicine. In this study, phosphorylated PAMAM (P-PAMAM) dendrimers were synthesized based on the idea of mimicking the phosphorylated proteins of dentin non-collagenous proteins (DNCP). Then, proliferation and osteo/odontogenic differentiation effects of P-PAMAM on dental pulp stem cells (DPSCs) were investigated and were compared with DNCP. P-PAMAM was synthesized via the Mannich-type reaction. DNCP were extracted directly from human dentin with ethylenediaminetetraacetic acid (EDTA) solution. Then, the conditioned medium of P-PAMAM and DNCP were prepared respectively and applied to DPSCs. Proliferation of P-PAMAM was investigated with CCK-8, flow cytometry, and EdU test. Osteo/odontogenic differentiation of P-PAMAM was analyzed using alkaline phosphatase activity and staining, RT-PCR, western blot, alizarin red staining, and immunofluorescence staining. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance revealed that PAMAM were successfully phosphorylated. Western blot verified that the extracted DNCP contained dentin-related proteins DSPP, OPN, and BMP2. In cell proliferation, there was no apparent difference between P-PAMAM, DNCP, and Control groups (P > 0.05). P-PAMAM and DNCP upregulated related genes and proteins expression (DSPP/DSPP, COL-1/COL-1, ALP/ALP, RUNX2/RUNX2, OSX/OSX, OCN/OCN) and matrix mineralization. Still, the potential was lower than that of DNCP (P < 0.05). P-PAMAM dendrimers, as a biomimetic analog of DNCP, promote osteo/odontogenic differentiation of DPSCs without influencing their proliferation at a low concentration. This preliminary study about P-PAMAM dendrimers is expected to provide a more convenient bioactive macromolecular material for the regeneration of the pulp-dentin complex.

Encapsulation of Enzymes in Metal-Phenolic Network Capsules for the Trigger of Intracellular Cascade Reactions.

Nanoengineered capsules encapsulated with functional cargos (e.g., enzymes) are of interest for various applications including catalysis, bioreactions, sensing, and drug delivery. Herein, we report a facile strategy to engineer enzyme-encapsulated metal-phenolic network (MPN) capsules using enzyme-loaded zeolitic imidazolate framework nanoparticles (ZIF-8 NPs) as templates, which can be removed in a mild condition (e.g., ethylenediaminetetraacetic acid (EDTA) solution). The capsule size (from 250 nm to 1 μm) and thickness (from 9.8 to 33.7 nm) are well controlled via varying the template size and coating time, respectively. Importantly, MPN capsules encapsulated with enzymes (i.e., glucose oxidase) can trigger the intracellular cascade reaction via the exhaustion of glucose to produce H2O2 and subsequently generate toxic hydroxyl radicals (•OH) based on the Fenton reaction via the reaction between H2O2 and iron ions in MPN coatings. The intracellular cascade reaction for the generation of •OH is efficient to inhibit cancer cell viability, which is promising for the application in chemodynamic therapy.

The Effect of Photodynamic Therapy on the Smear Layer Removal: a Scanning Electron Microscopic Study.

Statement of the Problem: The efficacy of photodynamic therapy (PDT) in smear layer removal compared to the currently accepted protocol is not well established.Purpose: This study aims to evaluate the effect of PDT on smear layer removal from human root canal compared to combined use of irrigation solutions including sodium hypochlorite (NaOCl) and ethylene diamine tetra acetic acid (EDTA) by scanning electron microscopy (SEM).Materials and Method: In this in vitro study, straight roots from 48 extracted human maxillary incisors and canines were selected and decoronated. Instrumentation was completed with RaCe rotary system and normal saline irrigation between files. Then roots were randomly divided into 3 groups (n=16). Group 1 was the control group to confirm smear layer formation. In the group 2, the canals were irrigated with 2ml of 2.5% NaOCl solution for 10 minutes and 2ml of 17% EDTA solution for 1 minute. In the group 3, PDT with methylene blue and diode laser (625nm, 150mW, for 5minutes) was the final procedure for smear layer removal. All the specimens were sectioned into two halves, gold coated, and analyzed under SEM. The smear layer in the coronal, middle, and apical thirds, were evaluated and scored by two examiners independently. Statistical analysis was done using Chi-square test.Results: It was observed that the NaOCl+EDTA removed the smear layer significantly better than PDT in the coronal and apical thirds (p< 0.05) whereas PDT was unable to remove the smear layer in none of the root areas. At the apical thirds, there was no significant difference between NaOCl+EDTA and PDT (p< 0.05). Both procedures were unable to remove smear layer from radicular dentine of this area.Conclusion: According to the results of this in vitro study, the use of PDT alone is not recommended to remove smear layer. The combined application of NaOCl and EDTA is ineffective in removing smear layer of apical third, despite its efficacy on the coronal and middle regions.

Continuous Injection Isothermal Titration Calorimetry for In Situ Evaluation of Thermodynamic Binding Properties of Ligand-Receptor Binding Models.

We utilize a continuous injection approach (CIA) rather than the traditional incremental injection approach (IIA) to deliver ligand (or receptor) to the calorimeter cell to evaluate thermodynamic binding parameters for three common ligand-receptor binding models-single independent, competitive, and two independent binding sites-using isothermal titration calorimetry (ITC). A general mathematical expression for the binding isotherm for any binding stoichiometry under continuous delivery of ligand (or receptor) resulting in an analytical solution for the thermodynamic binding parameters is presented. The advantages of CIA include reduction in experimental time, estimation of thermodynamic binding parameter values, and automation of the experiment since thermodynamic parameters are estimated in situ. We demonstrate the inherent advantages of CIA over IIA for the three binding models. For the single independent site model, we utilized the binding of Ba2+ ions to ethylenediaminetetraacetic acid (EDTA), while competitive binding was captured by titration of Ca2+ ions into a buffered solution of Ba2+ and EDTA. We experimentally simulated a two independent binding site system by injecting Ca2+ into a solution of EDTA and 1,3-diaminopropane-N,N,N',N'-tetraacetic acid (DPTA). The results demonstrate estimation of thermodynamic parameters with greater confidence and simultaneous reduction in the experimental time of 83% and titrating reagent of 50%, as compared to IIA.

In vitro study on conditioned dental root surfaces: evaluation of wettability, smear layer, and blood clot adhesion.

The aim was to investigate the efficacy of citric acid and ethylenediaminetetraacetic acid (EDTA)-based treatments on smear layer removal and blood clot formation and stabilization. After scaling and root planing, 126 root samples were divided into seven groups treated with: deionized water; saline; citric acid solution; Ultradent Citric Acid gel; EDTA solution; EDTA-based PrefGel; or untreated. Each group was divided into three subgroups: I for the evaluation of smear layer removal and surface wettability, II and III for the evaluation of blood clot formation and stabilization in static or dynamic rinsing conditions. Conditioning agent treatments increased surface wettability with respect to untreated samples (Ultradent: 45 ± 1 degrees, P = 6.2 × 10-3; EDTA: 36 ± 5 degrees, P = 8.9 × 10-7; PrefGel: 47 ± 7 degrees, P = 3.2 × 10-2). Smear layer removal (30% to 60% with respect to untreated samples) was observed for all the conditioning agents. Clot was absent on untreated samples and samples treated with deionized water. Clot quality was significantly higher for samples treated with conditioning agents (P < .05) and similar between group II and III (P > .05). A statistically significant difference (P = .027) was observed for clot coverage of the saline group, comparing static and dynamic rinsing, confirming the positive effect of treatments on clot stabilization. The use of conditioning agents improves smear layer removal and clot formation and stabilization with respect to scaling and root planing procedure only, which is, however, considered an essential procedure to promote wound healing in periodontal surgery.

Evaluation of Restorative Techniques for Vertically Fractured Roots.

The purpose of this study was to examine the effects of combining specific adhesive materials and various surface treatments on bonding durability and microleakage of vertically fractured roots. Adhesive models were prepared using bovine lower incisors. The experiment included the following five groups: SB-G group (control) (10% citric acid with 3% ferric chloride solution (10-3 solution) + an adhesive resin cement (4-META/MMA-TBB; Super-Bond®)), EC group (self-cure bonding agent (UB) + core composite resin (EC)), EC-G group (10-3 solution + UB + EC), EC-P group (40% phosphate solution + UB + EC), and EC-E group (18% ethylenediaminetetraacetic acid (EDTA) solution + UB + EC). After applying a load of 50,000 cycles, microleakage, microtensile bond strength (μTBS), and failure modes were examined. Microleakage of the EC, EC-G, and EC-E groups was significantly lower than that of the EC-P group. The μTBS of the EC-G group was significantly higher than that of the other groups. All EC groups showed that mixed (cohesive and adhesive) and adhesive failures were the most prevalent types of failure modes. The EC-G group showed the highest bonding durability and the lowest microleakage results, which indicates a possible alternative to current adhesive and tooth surface treatments.

Chelation-mediated synthesis of nanoporous gold at near-neutral pH and room temperature by free corrosion dealloying of gold-copper alloy driven by oxygen reduction

Dealloyed nanoporous gold (NP-Au) is commonly created with hazardous chemicals including strong oxidizing acids. This work presents a green alternative to the common methods for making NP-Au. In this work, we create NP-Au by free corrosion dealloying of a Au-Cu parent alloy at room temperature in a near-neutral pH aqueous solution of ethylenediaminetetraacetic acid (EDTA), a non-toxic chelating ligand. The oxygen reduction reaction (ORR), catalyzed by activated carbon cloth (ACC), is employed to drive selective oxidation of Cu into Cu2+ ions, and EDTA is used to sequester the Cu2+ ions, preventing passivating copper oxide (CuOx)-forming reactions. We call this methodology chelation-mediated dealloying. Using small-angle x-ray scattering (SAXS), x-ray diffraction (XRD), and scanning electron microscopy (SEM), we observe that the NP-Au produced under mild conditions is similar to that produced by free corrosion dealloying in nitric acid (HNO3), a highly hazardous and strong oxidizing acid.

Improved non-enzymatic H2O2 sensors using highly electroactive cobalt hexacyanoferrate nanostructures prepared through EDTA chelation route

Over the last decade, there have been increasing reports on novel synthesis approaches for nanostructured hexacyanoferrate materials due to their potential usage in a broad range of electrochemical applications. This study demonstrates a method for synthesis of Cobalt Hexacyanoferrate (CoHCF) nanostructures with controlled size, shape, and structure by nucleation rate control using the Ethylenediaminetetraacetic Acid (EDTA) chelation strategy. The differences in chemical and electronic structures of CoHCF nanostructures achieved through variation of EDTA solution pH were confirmed by characterization. The study demonstrated the role of material synthesis in achieving physical characteristics that led to improved electrochemical activity and charge transfer ability of CoHCF compounds. An increase in electroactive sites and access to those sites because of enhanced specific surface area and pore volume contributed to the superior electrochemical characteristics of the material. Sensors prepared with the synthesized CoHCF nanostructured materials showed much better amperometric sensing ability of H2O2 as compared to previously reported non-enzymatic sensors with similar materials.