Ethylenediaminetetraacetic Acid Research Articles

Frequency of Nutritional Megaloblastic Anemia among Students in Khartoum, Sudan

Background: Megaloblastic anemia is a generative macrocytic anemia characterized by nuclear dysmaturity and the nucleus immature appearance in comparison to the cytoplasm due to a defect in DNA synthesis anemia is a rare ailment in children that is usually caused by a vitamin deficiency or gastrointestinal disorder Objectives: The main objective of this study was to detect the frequency of nutritional megaloblastic anemia in male elementary-school children by measuring hemoglobin (Hb), red blood cell (RBC) count, hematocrit (HCT), and serum folate levels. Methods: This study examined 300 male primary-school children in Khartoum, Sudan. A 2.5-ml of blood was drawn from each student and placed in an ethylene diamine tetra acetic acid (EDTA) vial to estimate the Hb level, RBC count, and HCT using an automated blood analyzer. Another 2.5 mL of blood were drawn from the same students into a plain container and examined for serum folate. Results: The mean Hb was 12.7 g/dl (two standard deviations), the RBC count was 4.71012 cells/L, and the mean packed cell volume (PCV) was 37.2%, and the mean serum folate was 4.4 ng/L. Conclusion: The blood parameters and serum folate were found to be within normal ranges. According to the findings, the nutritional status of the primary-school students was good, and megaloblastic anemia was not common. This type of research should be done on a frequent basis to assess children's nutritional health.

Clinical characteristics and outcomes of band keratopathy: a 10-year retrospective analysis

Background: Band keratopathy is a chronic, degenerative corneal disease resulting from gradual calcium deposition in the superficial cornea. Herein, we report the spectrum of causes, treatment outcomes, and recurrence rates of band keratopathy at a tertiary referral center throughout one decade. Methods: This retrospective study included patients with clinical diagnoses of band keratopathy who were treated with combined ethylenediaminetetraacetic acid (EDTA) and superficial keratectomy with or without amniotic membrane transplantation (AMT). Patient medical records were reviewed, and detailed demographic and ophthalmological data, such as baseline and last follow-up best-corrected distance visual acuity (BCDVA), ocular or medical comorbidities, type of intervention, postoperative follow-up duration, relevant complications, and recurrence were recorded. Results: A total of 32 eyes of 29 patients with 3 (10.3%) bilateral and 26 (89.7%) unilateral cases of treatment-requiring bank keratopathy were included. The mean (standard deviation [SD]) (range) age was 39.4 (22.4) (2–74) years, and most patients were female. The most common secondary cause was previous vitreoretinal surgery with silicone oil tamponade (15.6%); however, idiopathic cases were the most common (18.8%). Systemic comorbidities were present in 27.6% of patients, consisting of hypertension, diabetes mellitus, epilepsy, coronary artery disease, Behcet’s disease, and juvenile idiopathic arthritis; however, none of the patients had systemic diseases associated with hypercalcemia. Two of the 3 patients with bilateral involvement had chronic uveitis secondary to systemic rheumatological disease. The mean (SD) follow-up duration was 5.6 (4.0) years, and no serious postoperative complications occurred. The mean (SD) baseline and final BCDVA in logarithm of the minimum angle of resolution (logMAR) were 1.98 (1.0) and 1.7 (1.0), respectively (P > 0.05). Combined EDTA chelation and superficial keratectomy with and without AMT were performed in 12.5% and 87.5% of eyes, respectively. Recurrence was observed in 37.5% of eyes within the mean (SD) (range) follow-up of 9.4 (9.1) (1–32) months. Seven of the 12 eyes with recurrence underwent re-EDTA chelation combined with superficial keratectomy and AMT; however, 5 patients managed conservatively. Conclusions: In this study, band keratopathy requiring intervention more commonly affected female individuals and was unilateral. Most cases were idiopathic. Systemic comorbidities were present in approximately one-third of cases. Managing band keratopathy using a combination of EDTA chelation and superficial keratectomy with or without AMT could be a potential treatment modality. Further large-scale studies are required to provide robust conclusions regarding the efficacy and safety of this management approach.

Spectroscopic and Electrochemical Studies of Interaction of Cu(II) Ion with Different Aliphatic and Aromatic Amine Based Ligands in Aqueous Solutions

The composition and stability constant of the complexes of copper(II) with the ligands 2,2 –bipyridine, 1,10-phenanthroline, saccharin, and ethylenediamine tetraacetic acid (EDTA),were determined, as well as the effect of temperature on the thermodynamic parameters were studied. The metal-to-ligand ratio in the EDTA complex is found 1:1 and in the rest of the cases, the ratio is 1:2. The redox behavior of the Cu (II) / Cu (0) system in the Cu-ligand complex has been studied in KCl solution as a supporting electrolyte. The redox process of the Cu (II) / Cu (0) system in the Cu-sac complex is almost similar to that of the Cu (II) solution in the absence of any ligand. In other cases, the redox process is a single-step 2-electron transfer process. The electron transfer process in all the cases is diffusion-controlled. The values of peak current ratio and peak potential separation are the evidence that the redox processes are quasi-reversible. Dhaka Univ. J. Sci. 72(2): 61-67, 2024 (July)

Effect of continuous vs sequential chelation on the mechanical properties of root dentin: An ex vivo study

ObjectivesTo evaluate the mechanical properties of root canal dentin treated with sodium hypochlorite (NaOCl) in combination with hydroxyethylidene diphosphonic acid (HEDP) or ethylenediaminetetraacetic acid (EDTA). MethodsFor testing fracture resistance, 45 single-rooted teeth were instrumented and irrigated with NaOCl/HEDP, NaOCl/EDTA, or distilled water. Fifteen untreated teeth served as control. After obturation, specimens from the experimental groups were thermocycled, dynamically-loaded, and then statically-loaded in a universal testing machine until failure. For flexural strength analysis, 15 teeth were instrumented and irrigated with NaOCl/HEDP or NaOCl/EDTA. Root segments were sectioned into dentin bars and tested for flexural strength using a universal testing machine. For microhardness evaluation, 20 teeth were instrumented and irrigated with NaOCl/HEDP or NaOCl/EDTA. Dentin disks from the coronal-third of each root segment were prepared, one before and one after irrigation, for microhardness testing with a Knoop hardness tester. ResultsThe highest fracture resistance was recorded in the untreated group, and the lowest in the EDTA group. Although the HEDP group had higher fracture resistance than the EDTA group, the distilled water group demonstrated even greater fracture resistance than the HEDP group. Specimens treated with HEDP had significantly higher flexural strength and microhardness values when compared with those treated with EDTA. ConclusionThe fracture resistance, flexural strength, and microhardness of root canal dentin were higher when root canals were irrigated with NaOCl/HEDP, when compared with NaOCl/EDTA. Clinical significanceIrrigating root canals with NaOCl combined with HEDP significantly improves the mechanical integrity of root canal dentin compared to the use of NaOCl with EDTA.

A fluorescent probe derived from phenanthridine for selective detection of Bi3+ ion and its real-time application

To detect Bi3+ ion, a new phenanthridine-based sensing probe 5-(4-(benzyloxy)phenyl)-7,8,13,14-tetrahydrodibenzo [a,i]phenanthridine(BBA) was synthesized and characterized using mass spectral and NMR spectral analysis. Even in the presence of other cations, the probe BBA showed notable color changes through the fluorescence turn-on process when exposed to Bi3+ ions. It was found that the Limit of Detection of Bi3+ was 200 pM, and the reaction time was as low as 10 s. Additionally, it was found that adding ethylenediaminetetraacetic acid (EDTA) to BBA + Bi3+ made BBA, a reversible sensor. Test strips and real water sample experiments demonstrated the potential of the probe BBA for sensing Bi3+ in the environment. The sensing mechanism of BBA was investigated using Gaussian 16 software by performing Density Functional Theory (DFT) calculation. DFT calculations provided a theoretical validation of the experimental results. The practical application of BBA as a Bi3+ sensor has been expanded to include quantitative analysis of bismuth ions in tablets containing Bi3+.

An artificial intelligence handheld sensor for direct reading of nickel ion and ethylenediaminetetraacetic acid in food samples using ratiometric fluorescence cellulose paper microfluidic chip

User-friendly in-field sensing protocol is crucial for the effective tracing of intended analytes under less-developed countries or resources-limited environments. Nevertheless, existing sensing strategies require professional technicians and expensive laboratory-based instrumentations, which are not capable for point-of-care on-site analyses. To address this issue, artificial intelligence handheld sensor has been designed for direct reading of Ni2+ and EDTA in food samples. The sensing platform incorporates smartphone with machine learning-driven application, 3D-printed handheld device, and cellulose paper microfluidic chip stained with ratiometric red-green-emission carbon dots (CDs). Intriguingly, Ni2+ introduction makes green fluorescent (FL) of CDs glow but red FL fade because of the coordination of Ni2+ with CDs verified by density functional theory (DFT), concurrently manifesting continuous FL colour transition from red to green. Subsequent addition of EDTA renders FL of CDs-Ni2+ recover owing to the capture of Ni2+ from CDs by EDTA based on strong chelation effect of EDTA on Ni2+ confirmed via DFT, accompanying with a noticeable colour returning from green to red. Inspired by above FL phenomena, CDs-based cellulose paper microfluidic chips are first fabricated to facilitate point-of-care testing of Ni2+ and EDTA. Designed fully-automatic handheld sensor is utilized to directly output Ni2+ and EDTA concentration in water, milk, spinach, bread, and shampoo based on wide linear ranges of 0–48 μM and 0–96 μM, and low limits of detection of 0.274 μM and 0.624 μM, respectively. The proposed protocol allows for speedy straightforward on-site determination of target analytes, which will trigger the development of automated and intelligent sensors in near future.

Innovative iron‑manganese modified microalgae biochar for efficient phosphate iron removal from water: Preparation and adsorption mechanisms

This study developed a novel FeMn composite biochar (FMBC) with the pyrolysis raw resource of Chlorella, applying for phosphates removal from the aqueous. Under optimal conditions, the FMBC prepared from microalgae achieved a phosphate removal rate of approximately 91.6 % (adsorption capacity: 23.23 mg/g) within 120 min, demonstrating superior adsorption performance compared to the pristine biochar. Response Surface Methodology (RSM) was applied for FMBC preparation optimization. To improve the metal loading capacity of biochar, Ethylene Diamine Tetraacetic Acid (EDTA) was used as a chelating agent during the preparation process. The optimum preparation conditions for FMBC were Fe/biomass(w/w) ratio of 1.25, Mn/biomass(w/w) ratio of 1.10, pyrolysis time of 120 min, and pyrolysis temperature of 650 °C, which presented a large specific surface area (14.681 m2/g), pore volume (0.036 cm3/g) with the rich oxygen-containing functional groups. Phosphorus removal kinetic and isotherm process were better described by pseudo-second-order model and the Dubinin-Radushkevinch (D-R) isotherm. In addition, the optimal adsorption conditions for FMBC were as follows: biochar dosage of 0.1 g, initial pH of 7.0, adsorption temperature of 25 °C, and initial phosphate concentration of 50 mg/L. Physical adsorption, surface complexation, precipitation, electrostatic attractions, and ion exchange were responsible for phosphate adsorption process by FMBC. The main innovation of this study is the use of explosive growth algae to prepare metal-modified biochar for phosphorus removal from water bodies, to realize the goals of resource utilization of waste biomass and eutrophication control in water, which are significant for sustainable development.

Rapid microwave fabrication of highly luminescent nitrogen and phosphorous co-doped carbon quantum dots for the determination of glutathione in pharmaceutical supplements

A facile and sensitive nano-probe for spectrofluorometric glutathione (GSH) determination has been developed based on dual-doped nitrogen and phosphorus carbon quantum dots (NP@CQDs). The NP@CQDs were prepared, through a rapid, one-step microwave heating method in only 180 s with a high quantum yield (0.63) using ethylenediaminetetraacetic acid as carbon and nitrogen precursor and diammonium hydrogen phosphate as nitrogen and phosphorus dopant. The synthesised NP@CQDs had a maximum bluish fluorescence emission at 420 nm, after excitation at 360 nm. The luminescence of the prepared NP@CQDs was quenched via a static quenching mechanism by ferrous ions, while ferric ions did not affect the emission of NP@CQDs. GSH was mixed with ferric ions before adding NP@CQDs to exploit this observation. The attenuation in emission observed after adding NP@CQDs to GSH/ferric ions was directly related to the GSH concentration, as GSH worked to reduce the ferric ions present and produce ferrous ions. The proposed fluorometric method was validated in compliance with the International Council on Harmonization (ICH) guidelines. The proposed fluorescent nano-probe showed good linearity for GSH determination over a range of 0.5–10 µg/mL with % recoveries ranging between 99.50 and 101.86 %, and RSD less than 2 %. NP@CQDs were implemented for GSH determination in pharmaceutical supplementary capsules with respectable accuracy and precision. This approach is simple, reliable, accurate, specific, and it also does not require expensive chemicals or sophisticated equipment. This work opens up other uses of NP@CQDs in pharmaceutical and environmental analysis.

Inhalable drug-loaded silk fibroin carriers for pulmonary drug delivery.

The design and development of engineered micro and nano-carriers offering superior therapeutic performance compared to traditional delivery forms, are crucial in pharmaceutical research. Aerosolization and inhalation of carriers with improved solubility/stability of insoluble drugs, has huge potential for targeted drug delivery (DD) in various pulmonary diseases. Indeed, dedicated carriers must meet specific dimensional rules for proper lung delivery. Particles between 2-10 μm in size are normally deposited in the tracheobronchial region, while particles of 0.5-2 μm may be properly deposited in the alveoli. In this work, we report the development of inhalable nanostructured carries made of a 'green' bio-inspired polymer from aqueous solutions, i.e. silk fibroin (SF), efficiently loaded with a hydrophobic drug, i.e. the thyroid hormone levothyroxine (L-T4), a drug for the treatment of idiopathic pulmonary fibrosis. The aim is to optimize a standard method for the synthesis of SF-based nanocarriers with controlled size and shape, where a fine control of their geometrical properties is aimed at efficiently controlling the pulmonary DD. L-T4 loaded SF particles were synthesized through a one-pot co-precipitation method. Optimized systems were determined by varying the chemo-physical parameters during the synthesis. Ethylenediaminetetraacetic acid (EDTA) was used to remove CaCO3 cores. The proposed synthesis routes have led to two SF structures, whose structural heterogeneity and nanostructured morphology have been demonstrated using fluorescence microscopy, DLS, SEM and EDX. Two systems with varying shape and size have been obtained: (i) a flat disk-like SF structure with an irregular surface and an in-plane length of about 1-2 μm; (ii) solid SF nanospheres, obtained using ethylene glycol as additive, showing two size populations (main diameters of 0.5 μm and 1.7 μm). Solid nanospherical systems, in particular, show a tendency to arrange into agglomerates that, when loosely bound into smaller particles, can facilitate the delivery at the alveoli. Both formulations exhibited similar drug loading efficiencies, evaluated by HPLC analysis. However, SF nanospheres showed greater in vitro drug release after 24 hours. The demonstrated control over the characteristics imparted to the proposed DD systems may be critical to select the most suitable size/shape to achieve high rates of delivery to the appropriate lung compartment.

Vermifiltration for removal of emerging contaminant EDTA (ethylenediaminetetraacetic acid). Kinetics models for adsorption, bio- and vermidegradation

Vermifiltration is a sustainable technology that combines the action of microorganisms and earthworms to remove contaminants in wastewater. In this work, vermifiltration was used to remove the emerging contaminant, EDTA, from simulated greywater. Three types of filters were designed: Azide Filter (AF) to evaluate the adsorption process, Bio filter (BF), to evaluate adsorption plus the action of the microorganisms, and Vermi Filter (VF), to assess the previously described processes and the action of the earthworms. Each filter was filled with gravel, sand and an active layer, and VF was inoculated with 60 Eisenia fetida. The filters were operated on a batch system with recycling. Different regimes were observed: an initial rapid decrease of EDTA concentration by adsorption; a lag phase, which lasted from 7 to 18 days, and a final EDTA decrease due to biological or vermi degradation. A mathematical model was developed performing the EDTA mass balance in the system and considering a first order kinetic rate for EDTA removal. Experimental data was fitted by the model, determining kinetic constants for adsorption or degradation process, kads and kd respectively. The kads values were similar for all filters, whereas VF showed a kd 53 % higher than that of BF and AF. Earthworms survival was 85 % and, although the biomass was significantly reduced (64.8 %), there was cocoons and juveniles. Bioassays with Lactuca sativa showed no phytotoxicity of the treated wastewaters. All the systems were efficient but the VF was faster, supporting that vermifiltration is a suitable technology for treating EDTA greywater.

Comparative study of un-doped CeO2 and metal (Mn, Co, Fe)-doped CeO2 nanostructures for the removal of golden yellow dye from synthetic wastewater

ABSTRACT In this study, the activity of un-doped cerium oxide (CeO2) nanostructure with metal (Mn, Co, Fe)-doped CeO2 nanostructures was compared as effective scaffolds for the elimination of Golden Yellow (GY) Dye. For this purpose, the un-doped and doped-CeO2 nanostructures were prepared through co-precipitation treatment and characterised using the following techniques like FTIR, XRD, UV, PL, SEM and EDX analysis. The synthetic nanostructures were selected for the removal of GY through adsorption and photocatalytic degradation from wastewater. Tauc’s model was employed to determine the optical band gap, and various key parameters (contact duration, pH, nanostructure dosage and GY concentration) were optimised for the adsorption/photocatalytic degradation of GY. The adsorption and degradation processes for these nanostructures were found to be pH-dependent, with an optimum pH value of 4. UV–visible spectroscopy was employed to probe the GY adsorption followed by the GY degradation, revealing a higher removal and degradation efficiency of 39.89% and 58.46% for Mn-CeO2, 34.60% and 47.21% for Co-CeO2 and 31.67% and 39.10% for Fe-CeO2 compared to 14.05% and 30.37% for un-doped CeO2, respectively. In total, 98.35% of GY removal was achieved by Mn-CeO2 compared to 44.42% by un-doped CeO2 within 175 min via adsorption (50 min) followed by degradation (125 min). Additionally, the absorption mechanism underwent analysis, with the kinetic data aligning closely with the pseudo-first-order model. Examination of the adsorption capacity at various equilibrium concentrations of the dye solution revealed the formation of monolayers and chemisorption phenomena. Moreover, the rate constant dropped when scavengers like ethylenediaminetetraacetic acid (EDTA), isopropyl alcohol (IPA), and hydrogen peroxide (H2O2) were added because they capture holes (h+), hydroxyl radicals (·OH), and superoxide radicals (·O2 −) respectively, with EDTA showing more prominent effects.

A novel interferometry-based optical sensor to study the coagulation of human plasma

We propose and demonstrate a Twin-interferometry (TIM) based optical approach for studying and exploring anisotropy and directional dependent coagulation kinetics in human plasma under isothermal condition. Human plasma is obtained by centrifuging blood samples collected in Ethylenediamine tetra acetic acid (EDTA) coated vials at 6000 RPM in a laminar flow unit. 0.5 ml of plasma is collected in an optically flat disposable glass cuvette and subjected to induced coagulation by adding equal amounts of CaCl2 solution as coagulant at seven different concentrations. A Twin-interferometer is designed to record the rate of shift in Michelson’s fringes caused by rate of change of optical path difference of coagulating plasma in two orthogonal directions. A pair of interferograms, referred to as the Twin- interferogram (TIG), are recorded for all plasma samples with different CaCl2 concentration during its coagulation. A new approach for extracting various coagulation parameters from TIG, such as anisotropy, half coagulation time, constants governing the rate and dimensionality of coagulation, and their variation along distinct direction is demonstrated. TIG results are validated using polarizing optical microscopic (POM) and optical extinction techniques.

Enhanced oil recovery and mitigating challenges in sandstone oil reservoirs employing EDTA chelating agent/ seawater flooding

While low salinity water (LSW) holds promise for improving oil recovery, its implementation is comparatively costly due to the substantial volumes of fresh water required to dilute seawater (SW). Additionally, concerns arise regarding potential issues related to LSW, including fines migration in sandstone reservoirs and scale formation in carbonate reservoirs. Chelating agents can be introduced into undiluted SW to bind with metal ions, thereby lowering its salinity. This approach mimics the behavior of LSW injection while overcoming associated challenges. This study involves measuring oil/injected solution interfacial tension (IFT), evaluating sandstone surface wettability alteration, along with conducting different sand pack flooding scenarios using Ethylenediaminetetraacetic acid (EDTA) chelating agent. The aim was to comprehend the EDTA oil recovery mechanisms and determine the optimal concentration of EDTA that minimizes chemical consumption while maximizing oil recovery. The findings indicated that incorporating 5 wt% EDTA into SW significantly reduced IFT from 29.52 mN/m to 4.75 mN/m, making the oil nearly miscible in the solution. Moreover, wettability tests confirmed that a minimum EDTA concentration of 5 wt% is required to shift wettability from oil-wet to strongly water-wet conditions. Sand pack flooding experiments, on the other hand, further demonstrated that this optimized fluid system can potentially recover an additional 16.1 % of oil following SW flooding. Finally, inductively coupled plasma (ICP) analysis revealed a notable increase in metal ion concentration during EDTA flooding, indicating enhanced leaching of metals from the sandstone surface and improved wettability characteristics.

The optimizing role of regulators in separation of lead − copper in seawater and analysis of related mechanism

Using seawater for mineral flotation conserves fresh water resources and offers significant environmental and economic benefits. However, the adverse effect of seawater restricts its application in mineral flotation. The regulators can eliminate the adverse effect caused by seawater during flotation separation of lead and copper. In this paper, the flotation separation of galena and chalcopyrite in seawater was tested. Compared with those in deionized water, the lead grade of concentrate in seawater flotation declined from 50.10% to 48.90%. Meanwhile, the recovery of galena declined from 74.33% to 60.58% and the SI value declined from 1.565 to 1.324. With the addition of SHMP (sodium hexametaphosphate), SS (sodium silicate) and EDTA (ethylenediamine tetraacetic acid), the SI value increased from 1.324 to 1.923, 2.002 and 1.939, respectively. Noteworthy, when EDTA was excessive, the grade of Pb was 60.80%, the recovery of galena was 60.86% and the SI value was 2.113. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Atomic force microscopy, Density functional theory calculation and E-DLVO calculation verified the micro-flotation results and revealed the mechanism of action.

Microbial challenges and solutions in root canal therapy

Root canal therapy (RCT) faces significant challenges due to microbial invasion and biofilm formation within the root canal system. The intricate anatomy of root canals, including isthmuses, lateral canals, and apical deltas, provides a conducive environment for pathogenic microorganisms, complicating effective disinfection. Key pathogens such as Enterococcus faecalis and Candida albicans are highly resilient, capable of forming biofilms that protect them from antimicrobial agents and host defences. Current antimicrobial strategies in endodontics combine mechanical instrumentation with chemical disinfection. Mechanical debridement, though essential, often falls short of thoroughly cleaning the complex root canal anatomy. Sodium hypochlorite (NaOCl), the gold standard irrigant, exhibits broad-spectrum antimicrobial properties but struggles to penetrate biofilms and dentinal tubules fully. Adjunctive solutions like chlorhexidine (CHX) and ethylenediaminetetraacetic acid (EDTA) enhance the antimicrobial efficacy of NaOCl by providing prolonged action and removing the smear layer, respectively. Intracanal medicaments, such as calcium hydroxide (Ca(OH)2), are utilized to maintain antimicrobial activity between treatment sessions. Despite its high pH and effectiveness against a wide range of bacteria, Ca(OH)2 shows limited efficacy against biofilm-forming bacteria like Enterococcus faecalis. Innovations in irrigation techniques, such as passive ultrasonic irrigation (PUI) and laser-activated irrigation (LAI), have improved the delivery and activation of irrigants, enhancing their ability to disrupt biofilms and penetrate the root canal system. Nanoparticle-based irrigants and medicaments represent a promising advancement in endodontic disinfection. Their small size and large surface area allow for better penetration and interaction with bacterial cells, significantly reducing bacterial load in the root canal system. Combining traditional and advanced antimicrobial strategies is essential for overcoming the limitations of current methods and improving the success rates of endodontic therapy. Understanding the mechanisms of microbial invasion and biofilm formation, along with integrating emerging technologies, can lead to more effective disinfection protocols. This approach aims to enhance treatment outcomes and ultimately ensure the longevity of endodontically treated teeth.

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.

In-situ electrochemical mapping of local activity on Zn and Zn-Al alloy electrodes by scanning electrochemical microscopy

Alternating-current scanning electrochemical microscopy (AC-SECM) is introduced to monitor the local activity of Zn and Zn-10Al alloy electrodes. In-situ AC-SECM maps at potentials near the open circuit potential (OCP) in 2 M NaCl (pH 10) indicate that the surfaces of Zn and Zn-10Al alloy electrodes are covered with the passivation layer. When the electrolyte is exchanged with a 0.1 M ethylenediaminetetraacetic acid (EDTA) containing electrolyte, AC-SECM maps at the potential near the OCP clearly reveal the active Zn and the distinct difference between Al- and Zn-rich phases. Thereby, it is demonstrated that EDTA enhances the electrochemical activities of Zn and Zn-10Al alloy electrodes. With shifting the potential to anodic potential of −1.0 V in 0.1 M EDTA containing electrolyte, the interfacial difference between Al- and Zn-rich phases slowly disappears in AC-SECM maps, confirming that the local activity of the surface observed by AC-SECM is only attributed to the metal-EDTA complex. It is noteworthy that the hindered diffusion at the confined space between the tip and the substrate (∼ 10 µm) certainly influences on the local activities of Zn and Zn-10Al alloy electrodes. Additionally, AFM results indicate that the slightly different interactions of EDTA with Al- and Zn-rich phases cause the roughness contrast.

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.

Supercritical carbon dioxide chelation extraction of heavy metal ions from drilling fluid waste: Experiment and simulation

This study evaluates the application of supercritical carbon dioxide chelation extraction technology for treating heavy metal ions (Zn2+ and Cr3+) in drilling fluid waste. Through a combination of experimental and molecular dynamics simulation methods, the influence of extraction parameters (temperature, pressure, duration, and chelating agents) on the extraction efficiency are investigated. Findings show that increased duration and pressure significantly improve extraction efficiency, while temperature has a complex effect, initially increasing efficiency but plateauing and slightly decreasing at higher temperatures. The optimum extraction condition with pressure of 220 bar, temperature 348.15 K and an extraction duration of 70 min using ethylene diamine tetraacetic acid (EDTA) as the chelating agent has been determined. Importantly, molecular simulation analysis revealed that citric acid outperforms EDTA in terms of Zn2+ and Cr3+ aggregation by forming larger aggregates with greater numbers of molecules while reducing overall aggregate count. Furthermore, optimization of extraction pressure in the EDTA system shows potential benefits. These results suggest that supercritical carbon dioxide chelation extraction technology has strong potential for environmentally friendly and reliable waste management in the drilling industry. This study represents a significant step forward in developing sustainable solutions for heavy metal removal from drilling fluid waste.

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.