Ethylenediaminetetraacetic Acid Research Articles

The phytosiderophore analogue proline-2′-deoxymugineic acid is more efficient than conventional chelators for improving iron nutrition in maize

ABSTRACT Iron (Fe) is an essential nutrient but has poor bioavailability because of its low solubility under conditions of high pH, such as calcareous soils. Previously, we synthesized an analogue of the natural Fe(III) chelator 2′-deoxymugineic acid secreted by graminaceous plants for efficient Fe uptake, designated as proline-2′-deoxymugineic acid (PDMA). Soil application of Fe(III)-PDMA ameliorated symptoms of Fe deficiency in rice. In the present study, we explored the potential of PDMA as Fe nutrition supplement in maize, a major graminaceous crop, and rice for comparison. In calcareous soil pots, Fe deficiency chlorosis of maize was efficiently recovered by a single application of Fe(III)-PDMA. In contrast, maize plants treated with conventional Fe(III)-chelator complexes, such as Fe(III)-ethylenediaminetetraacetic acid (EDTA) or Fe(III)-N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid monohydrochloride (HBED), showed little or no recovery. Similarly, rice Fe chlorosis in calcareous soil pots was efficiently recovered by a single application of Fe(III)-PDMA, but not by other conventional Fe(III)-chelator complexes. Application of Fe(III)-PDMA was also effective in ameliorating Fe deficiency chlorosis in hydroponically grown maize seedlings; other Fe(III)-chelator complexes showed minimal or no efficacy. Addition of low concentrations of metal-free PDMA recovered Fe chlorosis of maize or rice in the presence of Fe(III)-EDTA, suggesting possible ligand exchange from EDTA to PDMA for subsequent Fe(III)-PDMA uptake by ZmYS1 and OsYSL15 transporters. Similar effects were observed with Fe(III)-HBED, which has a higher stability constant, but to a lesser extent than Fe(III)-EDTA, suggesting that ligand exchange from HBED to PDMA might be less prone to occur than for chelators with moderate stability constants, such as EDTA. Ferric-chelate reductase assays of maize roots showed substantial reduction of Fe(III)-PDMA, but this reduction activity was not increased under Fe-deficient condition. These results suggested that PDMA is an efficient reagent for improvement of Fe nutrition in graminaceous crops, including maize, because of suitability of Fe(III)-PDMA as a substrate for chelation-based Fe uptake systems.

Enhanced Removal of Cd(II) Ions from Aqueous Media via Adsorption on Facilely Synthesized Copper Ferrite Nanoparticles

In this study, magnetic copper ferrite (CuFe2O4) nanoparticles were synthesized via the Pechini sol-gel method and evaluated for the removal of Cd(II) ions from aqueous solutions. PF600 and PF800 refer to the samples that were synthesized at 600 °C and 800 °C, respectively. Comprehensive characterization using FTIR, XRD, FE-SEM, HR-TEM, and EDX confirmed the successful formation of CuFe2O4 spinel structures, with crystallite sizes of 22.64 nm (PF600) and 30.13 nm (PF800). FE-SEM analysis revealed particle diameters of 154.98 nm (PF600) and 230.05 nm (PF800), exhibiting spherical and irregular shapes. HR-TEM analysis further confirmed the presence of aggregated nanoparticles with average diameters of 52.26 nm (PF600) and 98.32 nm (PF800). The PF600 and PF800 nanoparticles exhibited exceptional adsorption capacities of 377.36 mg/g and 322.58 mg/g, respectively, significantly outperforming many materials reported in the literature. Adsorption followed the Langmuir isotherm model and pseudo-second-order kinetics, indicating monolayer adsorption and strong physisorption. The process was spontaneous, exothermic, and predominantly physical. Reusability tests demonstrated high adsorption efficiency across multiple cycles when desorbed with a 0.5 M ethylenediaminetetraacetic acid (EDTA) solution, emphasizing the practical applicability of these nanoparticles. The inherent magnetic properties of CuFe2O4 facilitated easy separation from the aqueous medium using a magnet, enabling efficient and cost-effective recovery of the adsorbent. These findings highlight the potential of CuFe2O4 nanoparticles, particularly PF600, for the effective and sustainable removal of Cd(II) ions from water.

Modification of carbapenemase inhibition test and comparison of its performance with NG-Test CARBA 5 for detection of carbapenemase-producing enterobacterales.

Adequately and accurately identifying carbapenemase-producing Enterobacterales (CPE) is vital for selecting appropriate antimicrobial therapy and implementing effective infection control measures. This study aims to optimize the phenotypic detection method of carbapenemase for routine diagnostics in clinical microbiology laboratories. Carbapenemase genes in 2665 non-duplicate carbapenem-resistant Enterobacterales (CRE) clinical strains collected from various regions of China were confirmed through whole-genome sequencing (WGS). The carbapenemase inhibition test (CIT) was conducted and interpreted using different methods and breakpoints, then compared with the NG-Test CARBA 5 for carbapenemase detection. The diagnostic performance of the CIT method was optimal when the carbapenemase types were determined by comparing the inhibition zone diameters of the imipenem disc with 3-aminophenylboronic acid (APB) plus ethylenediaminetetraacetic acid (EDTA) to those of the imipenem disc with either APB or EDTA alone, with a breakpoint of 4mm. The overall sensitivities of the current CIT, the modified CIT and NG-Test CARBA 5 were 91.4%, 94.9% and 99.9%, respectively. For detecting isolates co-producing Klebsiella pneumoniae carbapenemase (KPC) and metallo-β-lactamases (MBLs), the modified CIT method had higher sensitivity than the current method (70.0%vs. 53.3%), though this difference was not statistically significant (p=0.063). The NG-Test CARBA 5 showed excellent performance for multi-carbapenemases diagnosis, with sensitivity and specificity of 97.1% and 100%, respectively. Optimizing and standardizing the CIT method for clinical use is necessary. It has certain advantages in diagnosing multi-carbapenemase and rare carbapenemase production. However, for identifying common carbapenemase types, the NG-Test CARBA 5 demonstrated superior performance.

Lewis-base ligand-reshaped interfacial hydrogen-bond network boosts CO2 electrolysis.

Both the catalyst and electrolyte strongly impact the performance of CO2 electrolysis. Despite substantial progress in catalysts, it remains highly challenging to tailor electrolyte compositions and understand their functions at the catalyst interface. Here, we report that the ethylenediaminetetraacetic acid (EDTA) and its analogs, featuring strong Lewis acid-base interaction with metal cations, are selected as electrolyte additives to reshape the catalyst-electrolyte interface for promoting CO2 electrolysis. Mechanistic studies reveal that EDTA molecules are dynamically assembled toward interface regions in response to bias potential due to strong Lewis acid-base interaction of EDTA4--K+. As a result, the original hydrogen-bond network among interfacial H2O is disrupted, and a hydrogen-bond gap layer at the electrified interface is established. The EDTA-reshaped K+ solvation structure promotes the protonation of *CO2 to *COOH and suppressing *H2O dissociation to *H, thereby boosting the co-electrolysis of CO2 and H2O toward carbon-based products. In particular, when 5mM of EDTA is added into the electrolytes, the Faradaic efficiency of CO on the commercial Ag nanoparticle catalyst is increased from 57.0% to 90.0% at an industry-relevant current density of 500mA cm-2. More importantly, the Lewis-base ligand-reshaped interface allows a range of catalysts (Ag, Zn, Pd, Bi, Sn, and Cu) to deliver substantially increased selectivity of carbon-based products in both H-type and flow-type electrolysis cells.

Pre-Sealing of Endodontic Access Cavities for the Preservation of Anterior Teeth Fracture Resistance.

Sodium hypochlorite solution (NaOCl) is an effective canal irrigant but interferes with the mechanical features of dentin and the bonding capability of adhesives when restoring endodontically treated teeth. This study evaluated whether access cavity resin sealing before using canal irrigant would augment the resistance of endodontically treated anterior teeth against fracture. Sixty maxillary incisors underwent endodontic treatment in five groups (n = 12). Irrigation with 5.25% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA) was performed in all groups except for Group 5. After root canal obturation, in Group 1, the access cavity was kept unrestored. In Group 2, immediate restoration after obturation was achieved. For Group 3, delayed restoration after 1 week was provided. In Group 4 (pre-sealed), before canal irrigation, the dentin surface of access cavities was sealed using self-adhesive composite resin (Vertise Flow) and then restored after obturation. In Group 5, which was saline irrigated, immediate restoration was performed. After storage and thermal cycling for 5000 cycles at 5°C-55°C with a dwell time of 15 s and a transfer time of 5 s, teeth were statically loaded by a universal testing machine until a fracture occurred. Data were collected as the fracture resistance (FR) and analyzed using the one-way analysis of variance and Tukey's tests. FR significantly differed between all groups (p < 0.001). The lowest FR was recorded in the unrestored group (284 ± 86 N), which was not statistically different from the immediately restored group (p = 0.065). The pre-sealed group exhibited the highest FR value (810 ± 127 N, p ≤ 0.02 vs. other groups). The FR of the saline-irrigated and delayed restored groups was almost similar (p = 0.13). NaOCl/EDTA irrigation resulted in an adverse effect on FR. Delayed restoration could reduce this adverse effect. Access cavity pre-sealing with flowable composites led to a higher FR than conventional methods and may be considered an effective step during treatment procedures.

Development and validation of stability indicating HPLC-DAD assay of adapalene, methylparaben and propylparaben in a cosmeceutical gel matrix with blueness, greenness and whiteness assessment via relative ranking: An ab initio-sub finem juxtaposed non-traditional approaches

Adapalene (ADA) is primarily used as a cosmeceutical gel in the treatment of mild-moderate acne and is also used off-label to treat keratosis pilaris as well as other skin conditions. A stability-indicating fit-for-purpose (FFP) method has been developed for co-determination of ADA, methylparaben (MPN), and propylparaben (PPN) combined in a cosmeceutical gel dosage form. This method was based on a reversed-phase RP-HPLC separation of the cited analytes. It avoided the use of tetrahydrofuran (THF), which is commonly used by both compendial and published procedures for determination of ADA, thus improving method blueness (applicability), greenness and whiteness. The method development and validation followed non-traditional eco-friendly approaches including chemical simulations and empirical modelling. The HPLC separation was performed on an RP Zorbax Eclipse XDB-C8 analytical column [150 × 4.6 mm, 5 µm (80 Å)] with gradient elution system of HPLC grade acetonitrile and 50 mM aqueous sodium dihydrogen phosphate buffer containing 5 mM ethylenediaminetetraacetic acid (EDTA) adjusted to pH 8.0 as the mobile phase at a flow rate of 2.5 mL min−1 and column oven was set at 25 °C. EDTA played an important role for reproducibility of retention time of the three analytes especially for ADA. It controlled control deprotonation of the three acidic analytes under study and hence reproduce their ionization, hydrophobicity, and hence retention time. Quantitation was achieved with the photodiode array detection (DAD) at wavelengths of 258 nm for both MPN and PPN and 312 nm for ADA. Target Measurement Uncertainty (TMU) for the three analytes was determined via two approaches; misclassification rates approach employing 100,000 Monte Carlo simulations (MCS) and in-specification probability (ISP) to ascertain fitness-for-purpose of the proposed method. Microsoft Excel workbooks were developed for both TMU calculation approaches in addition to calculation of procedure capability index (Ppk) and sigma level for each analyte and attached in the Supplementary material. Moreover, linearity of the method underwent additional assessment using the previously mentioned TMU and procedure capability determination techniques. The robustness of the method was checked using Plackett-Burman experimental design (PBD) as an empirical modelling technique which was examined thoroughly to detect some interactions. The calibration graphs for each drug were rectilinear in the range of 0.34–7.08, 0.38–7.00 and 0.08–1.75 µg mL−1 for ADA, MPN, and PPN, respectively. The stress testing revealed photostability of the three components and variable degrees of degradation in the other conditions. The proposed HPLC-DAD method was successfully validated and applied for the determination of the investigated analytes in a gel matrix. In addition, method blueness and greenness were comparatively evaluated via very recent approaches of Blue Applicability Grade Index (BAGI), Green Solvents Selection Tool (GSST), Spider Diagram for Assessment of the Green Analytical Index (SDAGI), Analytical Method Greenness Score (AMGS), Carbon Footprint (CF), Modified Complementary Green Analytical Procedure Index (ComplexMoGAPI), and Analytical GREEnness Metric Approach (AGREE). Furthermore, the method whiteness was assessed via Red Green Blue Twelve (RGB 12) model following a relative ranking approach.

Ion chromatography-pulsed amperometry method for determination of trace hydrogen sulfide in air

Hydrogen sulfide (H2S) is a pervasive gaseous pollutant that emits the characteristic odor of rotten gas, even at low concentrations. It is generated during various industrial processes, including petroleum and natural gas refining, mining operations, wastewater treatment activities, and refuse disposal practices. According to statistics from the World Health Organization (WHO), over 70 occupations are exposed to H2S, rendering it a key monitoring factor in occupational disease detection. Although H2S has legitimate uses in the chemical, medical, and other fields, prolonged exposure to this gas can cause severe damage to the respiratory and central nervous systems, as well as other organs in the human body. Moreover, the substantial release of H2S into the environment can lead to significant pollution. This noxious substance has the potential to impair soil, water, and air quality, while disrupting the equilibrium of the surrounding ecosystems. Therefore, sulfide has become one of the most commonly measured substances for environmental monitoring worldwide. Achieving the stable enrichment and accurate detection of low-level H2S is of great significance. Common methods for detecting this gas include spectrophotometry, chemical analysis, gas chromatography, rapid field detection, and ion chromatography. Although these methods provide relatively reliable results, they suffer from limitations such as high detection cost, low recovery, lack of environmental friendliness, and imprecise quantification of low-concentration H2S. Furthermore, the sampling processes involved in these methods are complex and require specialized equipment and electrical devices. Additionally, approximately 20% of the sulfides in a sample are lost after 2 h in a conventional alkaline sodium hydroxide solution, causing difficulties in preservation and detection. In this study, an accurate, efficient, and cost-saving method based on ion chromatography-pulse amperometry was developed for H2S determination. A conventional IonPac AS7 (250 mm×4 mm) anion-exchange column was employed, and a new eluent based on sodium hydroxide and sodium oxalate was used to replace the original sodium hydroxide-sodium acetate eluent. The main factors influencing the separation and detection performance of the proposed method, including the pulse amperage detection potential parameters and integration time, as well as the type and content of additives in the stabilizing solution, were optimized. The results showed that the proposed method had a good linear relationship between 10 and 3000 μg/L, with correlation coefficients (r2) of up to 0.999. The limits of detection (S/N=3) and quantification (S/N=10) were 1.53 and 5.10 μg/L, respectively. The relative standard deviations (RSDs) of the peak area and retention time of sulfides were less than 0.2% (n=6). The new method exhibited excellent stability, with up to 90% reduction in reagent costs. Compared with conventional ion chromatography-pulse amperometry, this method is more suitable for detecting low concentrations of sulfides in actual samples. Sulfides in a 250 mmol/L sodium hydroxide-0.8% (mass fraction) ethylenediaminetetraacetic acid disodium salt solution were effectively maintained for over 10 h. The new stabilizer significantly improved the reliability of both large-scale and long-term detection. The recovery of the proposed method was investigated by combining the system with a badge-type passive sampler. This sampling method requires no power devices; it is inexpensive, simple to operate, and can realize long-term sampling without the need for skilled personnel. Moreover, it can overcome the influence of short-term changes in pollutant concentration. The sampling results have high reference value for large-scale intervention-less pollutant monitoring in ultraclean rooms, museum counters, and other places. The results demonstrated that the recovery of the proposed method was greater than 95% for the blank sample and 80% for the sample plus standard solution. Finally, the newly established method was applied to determine H2S levels in air samples collected via passive sampling at school garbage stations. The measured results did not exceed the national limit.

Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is acellularreceptor for delta inulin adjuvant.

Delta inulin, or Advax, is a polysaccharide vaccine adjuvant that significantly enhances vaccine-mediated immune responses against multiple pathogens and was recently licensed for use in the coronavirus disease 2019 (COVID-19) vaccine SpikoGen. Although Advax has proven effective as an immune adjuvant, its specific binding targets have not been characterized. In this report, we identify a cellular receptor for Advax recognition. In vitro uptake of Advax particles by macrophage cell lines was substantially greater than that of latex beads of comparable size, suggesting an active uptake mechanism by phagocytic cells. Using a lectin array, Advax particles were recognized by lectins specific for various carbohydrate structures including mannosyl, N-acetylgalactosamine and galactose moieties. Expression in nonphagocytic cells of dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), a C-type lectin receptor, resulted in enhanced uptake of fluorescent Advax particles compared with mock-transfected cells. Advax uptake was reduced with the addition of ethylenediaminetetraacetic acid and mannan to cells, which are known inhibitors of DC-SIGN function. Finally, a specific blockade of DC-SIGN using a neutralizing antibody abrogated Advax uptake in DC-SIGN-expressing cells. Together, these results identify DC-SIGN as a putative receptor for Advax. Given the known immunomodulatory role of DC-SIGN, the findings described here have implications for the use of Advax adjuvants in humans and inform future mechanistic studies.

N-Formylation of Carbon Dioxide and Amines with EDTA as a Recyclable Catalyst under Ambient Conditions

The reduction of CO2 is an important method to produce chemicals such as methanol, formic acid, formaldehyde, etc. In general, the reduction of CO2 is carried out at high temperatures and pressures with precious metals as catalysts, which is not favorable for industrial procedures. Thus, it will be very useful if researchers can find cost-effective catalysts for industrial application in CO2 reduction. In this work, commercially available ethylenediaminetetraacetic acid (EDTA) was tested as a cheap, non-toxic, and recyclable catalyst to initiate the N-carbonylation reaction of CO2 with amines. After screening various reaction parameters, including temperature, pressure, time, solvent, and reducing agent, the optimal reaction conditions were obtained: 80 °C, 2 MPa, 6 h, 50 mmol% catalyst dosage, 1 mL DMSO, and 1:1 molar ratio of amine to reducing agent. Notably, further studies confirmed that EDTA could also be effective for N-formylation even under ambient conditions (0.1 MPa and room temperature). The suitability of the catalyst for 26 kinds of substrates (including aliphatic amines, aromatic amines, and alicyclic amines) and its reusability were also investigated, with satisfactory results. Scale-up research has been performed effectively with a high conversion of amine (83%) to obtain the mono-formylated product selectively. Finally, the mechanism of the reaction between amine and CO2 has been proposed via control experiments and compared with results in the literature.

Serial Nitrogen-Doped Metal/Carbon Composites Derived from Organic Salts for Superior Electromagnetic Wave Absorption and Supercapacitor Electrode.

The present study provides a facile one-pot pyrolysis strategy to prepare serial nitrogen-doped (N-doped) metal/carbon composites derived from six types of metal ethylenediaminetetraacetic acid (EDTA-M, M = Co, Cu, Mn, Fe, Mg, and Ca). N-doped Co/C composite integrated carbonaceous with magnetic components to attain dielectric-magnetic double loss mechanisms. The minimum reflection loss and effective absorption bandwidth reached -57.6 dB at 1.75 mm and 4.64 GHz at 1.52 mm, respectively. The electromagnetic simulation further confirms that the dissipation ability increases with the improvement of carbonization temperature. Results show that altering the metal species of precursors can significantly improve the electrochemical performance of the composites using the identical strategy. N-doped Cu/C composite performed a maximum specific capacitance of 2383.3 F g-1 at 0.5 A g-1 -1, and maintained 86.3% cycling stability at 20 A g-1 after 5000 cycles. The energy density of a symmetrical two-electrode configuration achieved 350.13 Wh kg-1 at a power density of 4000.04 W kg-1. Density functional theory calculations indicate that nitrogen dopants cause faster ion transport and stronger adsorption capacity. Moreover, the bifunctionality of other composites types are also systematically characterized.

Simultaneous quantification of baloxavir marboxil and its active metabolite in human plasma using UHPLC-MS/MS: Application to a human pharmacokinetic study with different anticoagulants

Baloxavir marboxil (BXM) is a cap-dependent nucleic acid endonuclease inhibitor, which exerts its antiviral effects after being metabolized to its active form baloxavir acid (BXA). Ethylenediamine tetra-acetic acid (EDTA) and heparin are the two most used anticoagulants in clinical blood sample collection to estimate drug levels in plasma. However, compared to heparin plasma, there is a lack of clinical pharmacokinetic data of BXA using EDTA anticoagulant tubes for blood collection. In the present study, an efficient, rapid, and sensitive ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous quantification of BXM and its active metabolite BXA in human plasma with its isotopic baloxavir-d5 (BXA-d5) as internal standard (IS). Plasma samples (50 μL) were undergone using acetonitrile containing 0.1 % formic acid a precipitant. Chromatographic separation was achieved by a Waters XBridge®C8 (2.1 mm × 50 mm, 2.5 µm) column. The gradient mobile phase was 0.1 % formic acid in water (A, pH 2.8) and 0.1 % formic acid in acetonitrile (B) and delivered at a flow rate of 0.6 mL/min for 4.5 min. BXM and BXA were monitored using a positive electrospray triple quadrupole mass spectrometer (TRIPLE QUAD™ 6500+) via multiple reaction monitoring mode. The mass-to-charge ratios (m/z) were 572.2→247.0, 484.2→247.0 and 489.2→252.0 for BXM, BXA, and BXA-d5 (IS). Calibration curves exhibited excellent linearity in the range of 0.1–10 ng/mL for BXM (r2 > 0.996), and 0.3–300 ng/mL for BXA (r2 > 0.998). Within-run and between-run precisions in coefficients of variations were less than 11.62 % for BXM and less than 7.47 % for BXA, and accuracies in relative error were determined to be within −7.78 % to 5.70 % for BXM and −6.67 % to 8.56 % for BXA. Extraction recovery efficiency was 92.76 % for BXM, 95.32 % for BXA, and 99.26 % for BXA-d5, respectively. The matrix effect of BXM and BXA was in line with the requirements, where the relative deviation of the accuracy was less than 6.67 % and the precision was less than 6.69 %. The validated efficient and simple UHPLC-MS/MS method was successfully used in the pharmacokinetic study of BXM and BXA in healthy human volunteers with K2EDTA and heparin tubes for blood collection. EDTA might compete with BXA for chelating metal ions and thereby decrease the plasma ratio in whole blood, leading to approximately 50 % lower measurement of pharmacokinetic parameters as compared with those obtained from heparin plasma anticoagulant tubes.

A ratiometric, turn-on fluorosensor for specific detection of Zn2+ ions

A potentially active fluorescent chemosensor (E)-2-(((2-(1H-benzo[d]imidazol-2-yl)phenyl)imino)methyl)-5-(diethylamino)phenol (BMDP) is developed by the condensation of 2-(2-aminophenyl)-1H-benzimidazole and 4-(diethylamino)salicylaldehyde. It shows an exceptional ratiometric fluorescence behavior when exposed to Zn2+ ions and the photoluminescence color is changed from blue to cyan under the exposure of a 365 nm UV light which is also strongly evident from the color chromaticity diagram. The exceptional ratiometric fluorescence behavior in the presence of Zn2+ ions is found to be due to the chelation-enhanced fluorescence (CHEF). The 1:1 stoichiometry of BMDP and Zn2+ ions in Zn2+ ions chelated BMDP complex is confirmed through Job’s plot analysis. Remarkably, Cd2+ does not interfere with the selective ratiometric fluorescence behavior induced by Zn2+ ions. The lowest detection limit and quantification limit are estimated to be 28 nM and 92 nM respectively. The cyan fluorescence of the Zn2+ ions chelated BMDP complex is interestingly reversed to the original BMDP in the presence of ethylenediamine tetraacetic acid (EDTA). At the molecular level, this can be thought of as a complimentary “INHIBIT” logic gate. Furthermore, it is possible to utilize the probe for on-site identification in test strips with improved Zn2+ ions selectivity. We have also used a smartphone-based method to demonstrate the usefulness of BMDP for the immediate quantification and detection of Zn2+ ions. In light of this, probe BMDP is a trustworthy fluorescence probe for on-site monitoring that can accurately identify Zn2+ ions even when some other metals and anions compete.

Staged Regenerative-Phenotype Modification Therapy for Multiple RT3 Gingival Recessions in Periodontally Compromised Anterior Mandibular Teeth: A Case Report.

We report the successful treatment of multiple recession type (RT) 3 gingival recessions in periodontally compromised mandibular anterior teeth with limited keratinized tissue. A 35-yearold man with stage III, grade C periodontitis underwent a two-stage intervention. Initially, a modification of the connective tissue graft (m-CTG) wall technique was used as part of phenotype modification therapy. The CTG acted as a protective 'wall,' securing space for periodontal regeneration, enhancing root coverage, soft tissue thickness, and keratinized mucosal width. Recombinant human fibroblast growth factor-2 and carbonate apatite promoted periodontal regeneration. This procedure successfully facilitated periodontal regeneration, resulting in the transition from RT3 to RT2 gingival recession and adequate keratinized mucosal width. Eighteen months later, the second surgery used a tunneled coronally advanced flap (TCAF) for root coverage. TCAF involved combining a coronally advanced flap and tunnel technique by elevating the trapezoidal surgical papilla and using a de-epithelialized CTG inserted beneath the tunneled flap. Root conditioning with ethylenediaminetetraacetic acid and enamel matrix derivative gel application were performed. Consequently, mean CAL gain was 5.3 mm, mean root coverage was 4.5 mm in height, and the gingival phenotype improved at the treated sites by the 12-month follow-up. This staged approach addresses the challenges of treating RT3 gingival recession with promising outcomes.

Endodontic irrigants from a comprehensive perspective.

This review article explores the fundamental principles of modern endodontics with a focus on root canal cleaning and shaping. It reviews commonly used endodontic irrigant, namely sodium hypochlorite (NaOCl), herbal extracts, chlorhexidine (CHX), and chelating agents, highlighting their properties, applications, and potential drawbacks. NaOCl, a key antimicrobial agent, demonstrates effectiveness against various microorganisms but poses challenges such as high cytotoxicity. Herbal extracts, gaining recognition in endodontics, present an alternative with potential advantages in preserving dentin integrity. CHX, known for its broad-spectrum antimicrobial activity, is discussed in both liquid and gel formulations, emphasizing its role in reducing smear layer formation and preserving hybrid layer durability. Chelating agents, specifically ethylenediaminetetraacetic acid and citric acid, play a vital role in removing the smear layer, enhancing dentin permeability, and facilitating the penetration of antimicrobial agents. The review article underscores the importance of careful application and consideration of each irrigant's properties to ensure safe and effective endodontic procedures. It serves as a valuable guide for clinicians in selecting appropriate irrigants based on specific treatment requirements.

Removal of Metal from Carboxypeptidase A Proceeds via a Split Pathway: Implications for the General Mechanisms of Metalloenzyme Inactivation by Chelating Agents.

The chelation of protein-bound metal ions is typically thought to follow either a dissociative (D) or an associative (A) path. While the former mechanism involves the spontaneous dissociation of the metal from the protein prior to chelation, the latter route is characterized by the formation of an intermediate protein-metal-chelator ternary complex. Using the prototypical zinc protease carboxypeptidase A (CPA) and a variety of charged and neutral chelating agents, we demonstrate that inactivation of the enzyme (and likely other metalloproteins) proceeds through a split pathway with contributions from both D- and A-type mechanisms. In the case of charged chelators such as ethylenediaminetetraacetic acid (EDTA), the proportions of both paths could be tuned over a wide range through variation of the chelator concentration and the ionic strength, I (from ∼95% A type at low I values to ∼5% at high I values). By measuring the EDTA concentration and time dependence of CPA inactivation and fitting the obtained kinetic data to a modified time-dependent inhibition model, we obtained the rate constants for the A and D paths (kinact and koff, respectively) and the inhibition constant (KI) for the formation of the CPA-Zn2+-EDTA ternary complex, indicating that the decreased contribution of the A-type mechanism at high ionic strengths originates from a large (40-fold; at I = 0.5 M) increase in KI. This observation might be related to a triarginine motif in CPA that electrostatically steers negatively charged substrates into the active site and may therefore also guide carboxylate-bearing chelators toward the Zn2+ ion.

Assessing Micronutrients in Soil with a New Chemical Extractant Using Isotopic Dilution Techniques: Linkages to Labile Fractions in Soil

ABSTRACT With the purpose of economizing the routine soil testing for micronutrients and avoiding the use of multiple soil extraction procedures, a laboratory investigation was attempted to evaluate a new chemical extractant for assessing the availability of common micronutrients (Fe, Cu, Mn, Zn, Mo, and B) in soils of widely varying properties (n = 32). The new extractant designated as OM-MES-VERA# contained 0.01 M oxalic acid, 0.02 M maleic acid, 0.02 M 2-(N-Morpholino) ethane sulfonic acid (MES), 0.0025 M ethylene diamine tetraacetic acid di-sodium salt, 0.02 M acetic acid, and 0.1% polyacrylamide (final pH adjusted to 6.0). OM-MES-VERA extracted significantly higher amounts of micronutrient cations and B from soils compared to the conventional diethylene triamine pentaacetic acid (DTPA, pH 7.3) extractable micronutrient cations and hot water soluble B, respectively, but lesser amount of Mo compared to Mehlich-3 universal extractant. Soil test values by both OM-MES-VERA- and conventional extractants were correlated with soil properties. The labile (E and L) values of micronutrient cations and Mo estimated by isotopic dilution method, ammonium bicarbonate-DTPA, pH 7.6 extractable soil B (as an estimate of E for B) and B concentration in maize (as an estimate of L for B) were successfully regressed on soil test values of micronutrients by OM-MES-VERA and conventional soil extractants except in the case of DTPA (pH 7.3) for E-value of Fe and L-value of Mn. The OM-MES-VERA extractant can be considered to assess the availability of common micronutrients in soils of diverse soil properties.

Electroless Copper Plating on a Cotton Surface: Effect of Metal Ion Ligand Stability Constant on Reduction Deposition.

Electroless plating facilitates the metallization of nonconductive substrate surfaces, and of note, the precise control of the bath stability constant influences the deposition process of metal particles. In this paper, trisodium citrate, potassium sodium tartrate, nitrogen triacetic acid, thiourea, and ethylenediamine tetraacetic acid disodium were selected as coordination agents, and the effect of the metal ion ligand stability constant on the reduction deposition was studied. Coordination bonds can be established between the Cu2+ and O/N/S particles in the ligand because paired electrons in O/N/S hybrid orbitals tend to occupy empty Cu2+ hybrid orbitals and establish coordination bonds. More importantly, the copper-potassium sodium tartrate ligand exhibits the lowest stability constant and lowest reduction barrier. As an exception, a consecutive Cu-plated coating with an excellent crystallinity property was deposited on the cotton surface when potassium sodium tartrate was used as the coordination agent in the plating solution. The deposition amounts are 55.2% and 74.1% after 1 and 4 h of electroless copper plating, respectively. The surface resistivity of Cu-plated cotton is 0.38 Ω/cm2, and additionally, the surface resistivity ratio before and after 1000 cycles fluctuated between 0.9 and 1.1, indicating that the Cu-plated cotton exhibits outstanding flexibility. In this paper, the deposition rate can be optimized by adjusting the copper particle ligand stability constant in the plating solution, aiming to achieve optimal results.

Oxide‐Encapsulated Silver Electrocatalysts for Selective and Stable Syngas Production from Reactive Carbon Capture Solutions

AbstractElectrolysis of bicarbonate‐containing CO2 capture solutions is a promising approach towards achieving low‐cost carbon‐neutral chemicals production. However, the parasitic bicarbonate‐mediated hydrogen evolution reaction (HER) and electrode instability in the presence of trace impurities remain major obstacles to overcome. This work demonstrates that the combined use of titanium dioxide (TiO2) overlayers with the chelating agent ethylene diamine tetra‐acetic acid (EDTA) significantly enhances the selectivity and stability of Ag‐based electrocatalysts for bicarbonate electrolysis. The amorphous TiO2 overlayers suppress the HER by over 50 % at potentials more negative than −0.7 V vs. RHE, increasing the CO faradaic efficiency (FE) by 33 % (relative). In situ surface‐enhanced Raman spectroscopy (SERS) measurements reveal the absence of near‐surface bicarbonate species and an abundance of CO2 reduction intermediates at the Ag|TiO2 buried interface, suggesting that the overlayers suppress HER by blocking bicarbonate ions from reaching the buried active sites. In accelerated degradation tests with 5 ppm of Fe(III) impurity, the addition of EDTA allows stable CO production with &gt;47 % FE, while the electrodes rapidly deactivate in the absence of EDTA. This work highlights the use of TiO2 overlayers for enhancing the CO : H2 ratio while simultaneously protecting electrocatalysts from impurities likely to be present in “open” carbon capture systems.

Evaluation of Physical Properties in Carboxymethyl Chitosan Modified Glass Ionomer Cements and the Effect for Dentin Remineralization: SEM/EDX, Compressive Strength, and Ca/P Ratio.

The aim of this article was to evaluate the effects of modifying glass ionomer cement (GIC) with carboxymethyl chitosan (CMC) on surface morphology and remineralization outcomes by examining dentin morphology and calcium ion composition changes. Thirty holes in a cylindrical acrylic mold were filled with three groups of restorative materials: GIC, GIC modified with CMC (GIC-CMC) 5%, and GIC-CMC10%. The surface morphology of each group's materials was observed using scanning electron microscopy (SEM). The compressive strength measurement was performed using a universal testing machine. The dentin remineralization process was performed by applying GIC, GIC-CMC5%, and GIC-CMC10% materials for 14 days on demineralized dentin cavities treated with 17% ethylenediamine tetraacetic acid (EDTA) for 7 days. A morphological evaluation was conducted using SEM. The calcium ion composition and calcium-to-phosphorous (Ca/P) ratio were examined using an energy-dispersive X-ray (EDX). The Kruskal-Wallis and post-hoc Mann-Whitney U tests were performed to compare all four groups of calcium ions (p < 0.05). The modification of GIC with CMC affected the morphological changes in the materials in the form of reduced porosity and increased fractures. A significant difference was found in compressive strength between the GIC-CMC modification materials of GIC-CMC5% and GIC-CMC10% and the GIC control group. The dentin tubule morphology and surface changes were observed after applying GIC, GIC-CMC5%, and GIC-CMC10% materials for 14 days, as evaluated by SEM. The EDX examination showed an increase in calcium ion content and hydroxyapatite formation (Ca/P ratio) after applying the GIC-CMC10% material. The surface porosity of the GIC modification material with the addition of CMC tended to decrease. However, an increase in cracked surfaces that widened, along with the rise in CMC percentage, was found. This modification also reduced the compressive strength of the materials, with the lowest average yield at 10% CMC addition. Therefore, the modification of GIC with CMC affects changes in morphology, calcium ion composition, and Ca/P ratio in demineralized dentin.

Can ethylene diamine tetra-acetic acid improve calcium fracture when combined with intravascular lithotripsy?

Key points Agents which dissolve hydroxyapatite may synergize with intravascular lithotripsy (IVL) to treat calcium plates more extensively, facilitating greater penetration of drug‐coated balloons delivered agents and maintain gain in lumen area without stenting. Dissolving hydroxyapatite could potentially allow more frequent use of high‐pressure balloons without IVL or atherectomy to fracture calcium plates, offering a lower cost approach. Other mechanisms such as debonding between calcium plate and fibrous tissue junctions may also be enhanced with IVL and calcium‐modifying agents to improve calcified vessel compliance.