High Inhibitory Concentration Research Articles

Biofilm Formation and Plasmid-Mediated Quinolone Resistance Genes at Varying Quinolone Inhibitory Concentrations in Quinolone-Resistant Bacteria Superinfecting COVID-19 Inpatients.

The likelihood of antimicrobial failure in COVID-19 patients with bacterial superinfection arises from both phenotypic (biofilms) and genotypic mechanisms. This cross-sectional study aimed to determine the inhibitory concentrations of quinolones-nalidixic acid, norfloxacin, ciprofloxacin, ofloxacin, and levofloxacin-in biofilm formers (minimum biofilm inhibitory concentration [MBIC]) and nonformers (minimum inhibitory concentration [MIC]) and correlate inhibitory concentrations with plasmid-mediated quinolone resistance (PMQR) genes in quinolone-resistant bacteria isolated from COVID-19 inpatients. Quinolone-resistant bacteria (n = 193), verified through disc diffusion, were tested for quinolone inhibitory concentrations using broth microdilution and biofilm formation using microtiter plate methods. The polymerase chain reaction was used to detect PMQR genes. Study variables were analyzed using SPSS v.17.0, with a significance level set at P <0.05. MIC-to-MBIC median fold increases for ciprofloxacin, ofloxacin, and levofloxacin were 128 (2-8,192), 64 (4-1,024), and 32 (4-512) in gram-positive cocci (GPC, n = 43), respectively, whereas they were 32 (4-8,192), 32 (4-2,048), and 16 (2-1,024) in fermentative gram-negative bacilli (F-GNB, n = 126) and 16 (4-4,096), 64 (2-64), and 16 (8-512) in nonfermentative gram-negative bacilli (NF-GNB, n = 24). In biofilm-forming F-GNB and NF-GNB, qnrB (10/32 versus 3/10), aac(6')-Ib-cr (10/32 versus 4/10), and qnrS (9/32 versus 0/10) genes were detected. A 32-fold median increase in the MIC-to-MBIC of ciprofloxacin was significantly (P <0.05) associated with qnrA in F-GNB and qnrS in NF-GNB. Biofilms formed by F-GNB and NF-GNB were significantly associated with the aac(6')-Ib-cr and qnrS genes, respectively. Nearly one-third of the superinfecting bacteria in COVID-19 patients formed biofilms and had at least one PMQR gene, thus increasing the need for quinolones at higher inhibitory concentrations.

Exploring the Effectiveness of 3-Chloro-4-morpholin-4-yl-1,2,5-thiadiazole as a Eco-Friendly Corrosion Inhibitor for Mild Steel in HCl Solution: Experimental and DFT Analysis

Corrosion is a significant issue in many industries, particularly where metals are exposed to harsh chemical environments. This study investigates the efficacy of 3-Chloro-4-morpholin-4-yl-1,2,5-thiadiazole (CMTD) as a corrosion inhibitor for mild steel in 1 M HCl solution across a temperature range of 303–333 K. Using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization techniques, the inhibition efficiency of CMTD was evaluated at different concentrations and temperatures. The results show that CMTD achieves a maximum inhibition efficiency of 96.8% at a highest inhibitor concentration, even at elevated temperatures. The adsorption of CMTD on the mild steel surface follows the Langmuir adsorption isotherm, with a calculated free energy of adsorption (ΔGads) of -39.5 kJ/mol, confirming a spontaneous chemisorption process. Quantum chemical Density Functional Theory (DFT) studies further elucidated the relationship between CMTD's molecular structure and its inhibition efficiency. Key parameters, including the energy gap (Egap = 3.551 eV), highest occupied molecular orbital (EHOMO = -6.317 eV), and lowest unoccupied molecular orbital (ELUMO = -2.766eV), were calculated to understand CMTD's reactivity. Additionally, global reactivity descriptors such as chemical hardness (η), electronegativity (χ), and the electron fraction transferred (ΔN) from CMTD to the iron surface were analyzed. These findings suggest that CMTD is highly effective in preventing corrosion and can be applied in industries where mild steel is exposed to acidic environments, such as in petrochemical and industrial cleaning processes.

Exploring Antimicrobial Potency, ADMET, and Optimal Drug Target of a Non-ribosomal Peptide Sevadicin from Bacillus pumilus, through In Vitro Assay and Molecular Dynamics Simulation.

The current study was designed to explore the biosynthetic potential of sevadicin in Bacillus pumilus species and its interaction with bacterial drug target molecules. The non-ribosomal peptide (NRP) cluster in B. pumilus SF-4 was preliminarily confirmed using PCR-based screening, and the bioactivity of strain SF-4 culture extract was assessed against a set of human pathogenic strains. The susceptibility assay showed that strain SF-4 extract had higher inhibitory concentrations (312-375µg/mL) than ciprofloxacin. Genome mining of B. pumilus strains (n = 22) using AntiSMASH and BAGEL identified sevadicin coding biosynthetic gene cluster only in strain SF-4, constitutes of two core biosynthetic genes, three additional biosynthetic genes, two transport-related genes, and one regulatory gene. The molecular docking of sevadicin with various putative bacterial drug targets such as dihydropteroate, muramyl ligase E, topoisomerase, penicillin-binding protein, and in vitro safety analyses were conducted with detailed ADMET screening. The results showed that sevadicin makes hydrophobic interaction with MurE (PDB ID: 1E8C and 4C13) via hydrogen bonding, suggesting bacterial growth inhibition by disrupting the cell wall synthesis pathway and exhibiting a secure biosafety profile. The stability and compactness of sevadicin/MurE complexes were assessed via molecular dynamic simulation using RMSD, RMSF, and Rg. The simulation results revealed the binding stability of sevadicin/MurE complexes and indicated that the complexes can't be easily deformed. In conclusion, the current study explored the biosynthesis of sevadicin in B. pumilus for the first time and found that sevadicin inhibits bacterial growth by inhibiting cell wall synthesis via targeting the MurE enzyme and exhibits no toxicity.

Rhodesain inhibitors on the edge of reversibility-irreversibility

A comparative study of Michael acceptor and keto-Michael acceptor inhibitors of the cysteine protease rhodesain has been performed. Five new inhibitors have been prepared bearing the peptide structure of the known cysteine protease inhibitor K11777 and differing on the warhead. For the preparation of the Michael acceptor warhead, a Horner-Wadsworth-Emmons reaction was used. In the synthetic routes of the keto-Michael acceptor warheads, keto-enoate and keto-vinyl sulfone, a metathesis reaction and a radical sulfonylation were the key steps, respectively. Interestingly, keto-Michael acceptors inhibited rhodesain through a dual mode of action, showing reversibility at low inhibitor concentrations and irreversibility at high inhibitor concentrations.

Adaptive evolution of Paecilomyces variotii enhanced the biodetoxification of high-titer inhibitors in pretreated lignocellulosic feedstock

High inhibitor concentrations in lignocellulose feedstock negatively affect the degradation rate of biodetoxification strains. This study designed two adaptive laboratory evolutions in solid substrate and liquid medium to boost the biodetoxification capacity of P. variotii to high titers of lignocellulose-derived inhibitors, resulting in two evolved strains AC70 and ZW70. The results showed that the evolutionary adaptation in liquid medium could better boost the acetic acid assimilation compared to that on solid substrate. Transcriptional analysis revealed that the evolved strains exhibited a significant upregulation of adh, acs, ach1, and ackA directly related to the initial steps of acetate and furan aldehydes metabolisms. ZW70 strain can effectively remove the high concentration inhibitors cocktail from the hydrolysates derived from pretreated wheat straw and furfural residues. The biodetoxified hydrolysates by ZW70 were successfully used for cellulose chiral L-lactic acid production with the titers of ∼110 g/L, which were over 20 % higher than that detoxified by parental strain.

Enhancing detoxification of inhibitors in lignocellulosic pretreatment wastewater by bacterial Action: A pathway to improved biomass utilization

The process of preprocessing techniques such as acid and alkali pretreatment in lignocellulosic industry generates substantial solid residues and lignocellulosic pretreatment wastewater (LPW) containing glucose, xylose and toxic byproducts. In this study, furfural and vanillin were selected as model toxic byproducts. Kurthia huakuii as potential strain could tolerate to high concentrations of inhibitors. The results indicated that vanillin exhibited a higher inhibitory effect on K. huakuii (3.95 % inhibition rate at 1 g/L than furfural (0.45 %). However, 0.5 g/L vanillin promoted the bacterial growth (−2.35 % inhibition rate). Interestingly, the combination of furfural and vanillin exhibited antagonistic effects on bacterial growth (Q<0.85). Furfural and vanillin could be bio-transformed into less toxic molecules (furfuryl alcohol, furoic acid, vanillyl alcohol, and vanillic acid) by K. huakuii, and inhibitor degradation rate could be promoted by expression of antioxidant enzymes. This study provides important insights into how bacteria detoxify inhibitors in LPW, potentially enhancing resource utilization.

Onion Peel Extract/Copper Oxide Nanoparticles as Corrosion Inhibitors for Carbon Steel in Hydrochloric Acid: Extraction, Characterization, Electrochemical Study, and Theoretical Explorations

The effectiveness of onion peel extract (OPE) as a corrosion inhibitor for carbon steel in a 1 M hydrochloric acid solution was investigated using weight loss (WL) techniques, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and surface morphological examination. Additionally, this process was characterized by Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and transmission electron microscopy (TEM). According to weight loss measurements, the protective efficiency of OPE increases with rising OPE concentration and decreases with increasing temperature of the corrosive solution. Polarization curves indicate that OPE acts as a mixed-type inhibitor in hydrochloric acid. The adsorption mechanism, supported by EIS results, shows that charge-transfer resistance increases and double-layer capacitance decreases with higher inhibitor concentration. The adherence of OPE to carbon steel follows the Langmuir isotherm, indicating a physical adsorption process, and the spontaneous adsorption of the inhibitor molecules is evidenced by the negative values of Gibb’s free energy of adsorption. The synergistic effect of copper oxide nanoparticles (CuO–NPs) in combination with OPE on the corrosion inhibition of carbon steel was also evaluated. The results demonstrated that the inhibition efficiency of OPE is enhanced in the presence of CuO–NPs due to synergistic interactions between OPE extract molecules and CuO–NPs. The electron-donating capacity of the chemical components in OPE was confirmed through theoretical studies employing quantum chemistry methods.

Evaluation of Corrosion Inhibition of Low-Carbon Steel Using Chamomile Plant Extract

The investigation focused on elucidating the corrosion inhibition mechanism of chamomile extract, serving as an environmentally sustainable inhibitor, across various concentrations (0.2, 0.4, 0.6, 0.8, 1.0 w/v %) applied to carbon steel immersed in a 0.6 M NaCl variations in temperature affect the solution. (303, 313, 323, 333 K). The analytical approach involved Assessment of weight reduction metrics complemented by sophisticated techniques, Scanning Electron Microscopy (SEM), Gas Chromatography-Mass Spectrometry (GC-MS), and Energy Dispersive X-ray Spectroscopy (EDS) were used to analyze the carbon steel surface with and without the extract. The principal aim was to conduct a detailed examination of the development of a layer of adsorption layer. The obtained results consistently validated a positive correlation between inhibition efficiency and extract concentration. SEM imaging visually substantiated a more extensive protective film at higher inhibitor concentrations, and EDS analysis corroborated these findings by detailing the elemental composition of the adsorbed layer. The observed reduction in inhibition efficiency with elevated temperatures suggests a thermodynamic effect, where increased temperatures diminish the adsorption of the inhibitor onto the metal surface. This comprehensive investigation establishes the potential of chamomile extract as an eco-friendly inhibitor for effectively mitigating corrosion on carbon steel in corrosive environments. The pinnacle of inhibition efficiency, reaching 96.55%, was achieved at the concentration of the inhibitor.

Towards the Targeted Protein Degradation of PRMT1.

Targeting the protein arginine methyltransferase 1 (PRMT1) has emerged as a promising therapeutic strategy in cancer treatment. The phase 1 clinical trial for GSK3368715, the first PRMT1 inhibitor to enter the clinic, was terminated early due to a lack of clinical efficacy, extensive treatment-emergent effects, and dose-limiting toxicities. The incidence of the latter two events may be associated with inhibition-driven pharmacology as a high and sustained concentration of inhibitor is required for therapeutic effect. The degradation of PRMT1 using a proteolysis targeting chimera (PROTAC) may be superior to inhibition as proceeds via event-driven pharmacology where a PROTAC acts catalytically at a low dose. PROTACs containing the same pharmacophore as GSK3368715, combined with a motif that recruits the VHL or CRBN E3-ligase, were synthesised. Suitable cell permeability and target engagement were shown for selected candidates by the detection of downstream effects of PRMT1 inhibition and by a NanoBRET assay for E3-ligase binding, however the candidates did not induce PRMT1 degradation. This paper is the first reported investigation of PRMT1 for targeted protein degradation and provides hypotheses and insights to assist the design of PROTACs for PRMT1 and other novel target proteins.

Autohydrolysis of sugarcane bagasse with water reuse: Impacts on residues’ composition and enzymatic hydrolysis

This work presents a new sequential approach to the sugarcane bagasse autohydrolysis process in a way that the liquor from the previous reaction was reused in the next one, and the makeup water for the next batch was used to wash the solid fraction before being added to the liquor in the next batch. This approach was suggested first as a way of reducing the water usage in the process, and second as a way of concentrating the liquor in any interesting component, working with the possibility of losing efficiency towards the glucose production through a cellulose loss to the liquor or enzymatic efficiency loss from a higher inhibitor concentration. Two sets of five sequential batches were performed: one washing the solids with the makeup water prior to the enzymatic step (Set 2), and the other one without the washing step (Set 1), looking forward to the effects of the water reuse over the glucose production and the liquor composition. Autohydrolysis pretreatment removed most of the hemicellulose (∼94 %), with liquor recycling improving its removal until the third batch and stabilizing after that. Although the washing step showed little impact on the composition of the solids, it was determinant to the success of the enzymatic hydrolysis, since it was possible to maintain the cellulose to glucose yield around 53% throughout the batches. There was a 64 % reduction in the water used in the sequential reactions without interfering in the glucose production, which indicates that the proposed strategy could be successfully used to reduce costs and environmental impacts associated with the pretreatment of lignocellulosic biomass.

Assessment of Common Factors Associated with Droplet Digital PCR (ddPCR) Quantification of Paratrichodorus allius in Soil.

This research investigated the factors associated with the quantitative detection of Paratrichodorus allius in soil using droplet digital PCR (ddPCR). Small-sized nematodes exhibited significantly lower DNA quantities compared to their medium and large counterparts. Soil pre-treatments (room temperature drying and 37 °C oven-drying) demonstrated no substantial impact on ddPCR detection, and soil storage (0-3 months at 4 °C) exhibited negligible alterations in DNA quantities. A commercial DNA purification kit improved the resulting quality of ddPCR, albeit at the cost of a notable reduction in DNA quantity. Upon assessing the impact of inhibitors from soil extracts, a higher inhibitor concentration (5%) influenced ddPCR amplification efficiency. Incorporating bovine serum albumin (BSA) (0.2 μg/μL or 0.4 μg/μL) into the ddPCR setup mitigated the issue. In brief, while ddPCR exhibits minimal sensitivity to soil pre-treatments and storage, higher concentrations of PCR inhibitors and the DNA purification process can influence the results. Despite ddPCR's capability to detect nematodes of all sizes, quantification may not precisely reflect soil population. Incorporating BSA into the ddPCR setup enhances both detection and quantification capacities. This study represents the first comprehensive investigation of its kind for plant-parasitic nematodes, providing crucial insights for application of ddPCR in nematode diagnosis directly from the soil DNA.

Studying the Effectiveness of an Expired Betamethasone Drug in Sulfuric Acid Solutions to Examine the Corrosive Behavior of Copper Using Weight Loss and Experimental Design

Utilizing expired pharmaceuticals as corrosion inhibitors for copper in acidic environments offers compelling advantages, including cost-effectiveness, reduced toxicity compared to traditional inhibitors, and contribution to pharmaceutical waste reduction through recycling. This study investigates the corrosion inhibition of copper in a sulfuric acid solution using varying concentrations of Expired Betamethasone Drug, employing weight loss and Experimental Design methods. The influence of temperature on copper's corrosion behavior is examined within the range of 293–333 K. Results show that inhibition efficiency increases with higher inhibitor concentrations but decreases with rising temperature. Thermodynamic analyses elucidate adsorption and activation processes, revealing that the adsorption of Expired Betamethasone Drug on copper surfaces is characterized as endothermic and spontaneous, aligning well with the Langmuir and Frumkin adsorption isotherms. The activation and free energies of inhibition reactions support a mechanism of physical adsorption. To establish the relationship between factors and responses, we employ response surface methodology (RSM) with regression statistical analysis and probabilistic assessment. Statistical analysis demonstrates highly significant quadratic models for inhibition efficiencies (IE) with a coefficient of multiple regressions (R²) of 0.999. Further model validation confirms a strong fit (adjusted R² = 0.997), with experimental observations closely matching predictions and a highly significant model (Q² = 0.989). The findings reveal that this expired drug exhibits substantial inhibitory power, exceeding 96%, in both experimental and predictive calculations.

Isolation and Characterization of Enterobacter sp Capable towards Tolerating Degradation Products and Fermenting Pentoses

&lt;p&gt;The depletion of fossil fuel resources, in addition to the growing demand for energy, has prompted the development of renewable energies, including bioethanol from lignocellulosic biomass. The acid pretreatment of hemicellulose releases inhibiting compounds in addition to xylose. With the possibility of exploitation of lignocellulose as a fermentation substrate, we isolated an &lt;em&gt;Enterobacter &lt;/em&gt;characterized by its ability to ferment xylose and tolerate high concentrations of inhibitors. The selection was performed in media containing different carbon and energy sources; glucose, cellobiose, CMC, furfural and 5-HMF. Characterization strategies of the selected strain such as, xylose concentration (from 25 g liter-1 to 100 g liter-1), furfural (0 mM to 25 mM), cell immobilization, were used to quantify the maximum yield of ethanol produced. The results obtained show that our strain can ferment up to 100 g liter-1 of xylose in the presence of 20 mM furfural at 37°C to produce ethanol with a maximum yield of 2.22 g liter- 1 for 24 h under 160 rpm magnetic stirring. The results obtained in this study suggest that the isolated &lt;em&gt;Enterobacter &lt;/em&gt;sp. is a promising strain for the bioconversion of lignocellulosic biomass pretreatment hydrolysate into bioethanol.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Anticorrosion studies of 5-acetyl-4-(3-methoxyphenyl)-6-methyl-1-phenyl-3,4-dihydropyrimidin-2(1H)-one: approach from experimental, DFT studies, and MD simulation

Abstract The effectiveness of 5-acetyl-4-(3-methoxyphenyl)-6-methyl-1-phenyl-3,4-dihydropyrimidin-2(1H)-one as a corrosion inhibitor for mild steel in acidic conditions was investigated herein through the experimental and theoretical approach. Experimental results demonstrated that this compound acts as a reliable corrosion inhibitor (η %) for mild steel in acidic environments, with its inhibition efficiency increasing as the inhibitor concentration rises. Adsorption behavior on the mild steel surface followed Langmuir and Temkin adsorption isotherms. Electrochemical polarization tests indicated that the compound exhibited a mixed corrosion type, and impedance spectroscopy revealed an increase in charge transfer resistance with higher inhibitor concentrations. Examination of the mild steel surface using SEM and Atomic Force Microscopy (AFM) confirmed the formation of a protective film. Wettability characteristics were assessed using the contact angle method. Frontier molecular orbital analysis revealed the HOMO and LUMO values for both the neutral and protonated forms of the compound. At 289 °C, the interaction energy for adsorption was found to be approximately −146.3006 kJ/mol for the neutral system and −135.8122 kJ/mol for the protonated system, while at 318 °C, the corresponding values were −140.6106 kJ/mol and −147.6022 kJ/mol. These findings collectively suggest the potential industrial utility of the investigated inhibitor as an effective corrosion inhibitor.

Abstract A037: Mechanisms of resistance to BAY 2927088, the first reversible inhibitor targeting EGFR exon 20 insertion mutations in non-small cell lung cancer

Abstract Molecular therapies targeting EGFR-mutant non-small cell lung cancer (NSCLC) have dramatically improved prognosis for patients with the classical activating mutations, L858R and exon 19 deletion. However, tumors harboring EGFR exon 20 insertions have been historically more difficult to target. Agents such as amivantamab and mobocertinib have recently been granted accelerated approval for treatment of lung cancer patients with exon 20 insertions, but agents with an improved selectivity profile versus wild-type EGFR are still needed. BAY 2927088, currently in phase I clinical trials, is a novel reversible inhibitor that targets EGFR exon 20 insertion mutations with decreased activity towards wild-type EGFR. Although most patients with advanced EGFR-mutant NSCLC eventually progress due to acquired resistance to EGFR inhibitors, the mechanisms of resistance to BAY 2927088 are currently unknown. Using two different methods of in vitro resistance generation by inhibitor treatment of sensitive cell lines, we identified mechanisms of intrinsic and acquired resistance to BAY 2927088 and other EGFR inhibitors. Incubation with a high concentration of inhibitor selected for drug-tolerant persister cells that underwent a transcriptional state transition resembling EMT (epithelial-mesenchymal transition). Conversely, gradual escalation of inhibitor concentrations resulted in acquisition of oncogenic NRAS mutations. In a parallel approach, we performed a deep mutational scanning assay of the EGFR D770_N771insSVD kinase domain, replacing each amino acid with every other possible amino acid, identifying both known and novel mutations that cause resistance to BAY 2927088 and other EGFR inhibitors. As expected, the C797S mutation was enriched as a mechanism of acquired resistance only to irreversible EGFR exon 20 insertion inhibitors. Surprisingly, the T790M gatekeeper mutation was found to cause resistance to all EGFR exon 20 insertion inhibitors tested, including irreversible inhibitors. Several novel resistance mutations clustering predominantly in exons 20 and 21 were also identified. Citation Format: Gizem Karsli Uzunbas, Quinn McVeigh, Akansha Gupta, Stephanie Hoyt, Kristen Doucette, Hasmik Keshishian, Steven Carr, Xiaoping Yang, David Root, Andrew D Cherniack, Franziska Siegel, Stephan Siegel, Matthew Meyerson, Heidi Greulich. Mechanisms of resistance to BAY 2927088, the first reversible inhibitor targeting EGFR exon 20 insertion mutations in non-small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A037.

Detection of the effect of silver nanoparticles prepared by using extract leaves Prosperis juliflora on pathogenic fungus Trichophyton tonsurans isolated from human scalp

The silver nanoparticles were prepared using Prosopis juliflora leaf extract and extracted from trees in Kirkuk city and showed that the silver nitrate solution in 1 mm turned its color brown which will be preliminary evidence of the formation of nanoparticles. The UV and visible absorption spectrum of a solution of silver nanoparticles was tested as a second step in confirming the formation of the particles, and it was found that they were present at the wavelength (440) nm, where it turned out that the peaks of X-ray diffraction were at (111), (220), (311) at angles (31.77, 48.11, 54.21) respectively. Trichophyton tonsurans were isolated from the scalp of a person with ringworm from Kirkuk General Hospital. The fungus was diagnosed on the basis of the phenotypic and microscopic characteristics and hair penetration. it was found that the solution of silver nanoparticle had a clear inhibitory effect on the fungus Trichophyton tonsurans. The highest and lowest inhibitor concentration reached 90% and the highest inhibitor concentration was 100 % Also, the ratios of the silver nanoparticles effects on the growth and production of fungi spores were determined.

Mild steel corrosion inhibition comparison between indole-5-carboxylic acid and benzofuran-5-carboxylic acid: An integrated experimental and theoretical study

Corrosion inhibition capabilities of Indole-5-carboxylic acid (IC) and Benzofuran-5-carboxylic acid (BC) on mild steel have been comprehensively investigated using various techniques, including Potentiodynamic Polarization Measurement (PPM), electrochemical impedance spectroscopy (EIS), and scanning electrochemical microscopy (SEM). The results from polarization tests demonstrated that both IC and BC effectively reduced the corrosion current densities of both cathodic and anodic reactions occurring on the metal surface. Through EIS analysis, it was observed that the inhibitory efficacy of IC and BC increased with higher inhibitor concentrations. At a temperature of 30°C, the solution containing 10−2M IC and 10−2M BC exhibited the maximum inhibitory efficiency, with IC achieving 92.19% and BC achieving 75.00%. The adsorption behavior of the inhibitors was found to follow the Langmuir isotherm, suggesting a monolayer adsorption process. Additionally, quantum chemical calculations were carried out to assess the molecular parameters of the inhibitors thoroughly. These calculations consistently indicated that IC exhibited superior inhibitory properties compared to BC. Furthermore, molecular dynamics simulations were employed to gain insights into the optimal adsorption configuration of the inhibitors on the Fe(110) surface. The results revealed that IC possessed a higher binding energy with the Fe(110) surface, confirming its superior ability to inhibit steel corrosion compared to BC.

ERG K+ channels mediate a major component of action potential repolarization in lymphatic muscle

Smooth muscle cells in the walls of collecting lymphatic vessels fire spontaneous action potentials (APs), which conduct rapidly over the muscle layer to initiate contractions that propel lymph. Several ion channels have been implicated in the currents underlying the AP spike and the preceding diastolic depolarization, but the molecular identities of K+ channels involved in AP repolarization are unknown. Based on previous studies of other rhythmically active smooth muscles, we hypothesized that ether-a-go-go related gene (ERG) K+ channels (Kv11) play an important role in repolarization of the AP in lymphatic muscle. Message for one or more ERG channel isoforms was detected by RT-PCR analysis of lymphatic vessels from mice, rats and humans. Membrane potential recordings in smooth muscle cells of rat and human lymphatics revealed that nanomolar concentrations of ERG-1 inhibitors (E-4031 and BeKm-1) prolonged the duration of the AP plateau (normally ~ 1 s in duration) and induced multiple spikes, whereas ERG-1 activators (ICA-105574 and RPR-260243) shortened the plateau and could completely inhibit spontaneous APs. At relatively high inhibitor concentrations, the AP plateau duration lasted as long as 24 s. ERG activators reversed the effects of ERG inhibitors and vice-versa. In pressure myograph studies, ERG channel inhibition prolonged the diastolic repolarization phase of the contraction cycle and reduced the frequency of spontaneous contractions. This is the first evidence for a specific K+ channel contributing to the AP in lymphatic muscle. Our results imply that lymphatic contractile dysfunction may occur in long QT type II patients with mutations that result in ERG channel loss-of-function or impaired trafficking of the channel to the cell membrane.

Investigating the use of Moringa Oleifera leaf extract as an environment-friendly corrosion inhibitor for API 5L X52 steel in 1 M HCl

This work studied the potential of using moringa oleifera leaf extract (MOLE) as an eco-friendly inhibitor for API 5L X52 steel in acidic media at 0.1 g/L–0.5 g/L concentration and 25 °C–60 °C. The study also evaluated the impact of adding potassium iodide (KI) to the corrosion-inhibiting properties of MOLE. Results from electrochemical testing showed that MOLE exhibited a high inhibition efficacy of 99% at 0.5 g/L concentration and 60 °C. The findings indicated that MOLE functions as a mixed-type corrosion inhibitor. Its efficiency increases with higher inhibitor concentrations following a Langmuir adsorption isotherm, and it is physically adsorbed on the steel surface. FT-IR spectra analysis revealed the presence of hydroxyl, carbonyl, saturated, and unsaturated aliphatic functionalities in the MOLE. The decreased absorption intensity in UV–vis spectra after 2 and 4 h of corrosive acid environment exposure indicates that MOLE was well adsorbed onto the metal surface. Hence, adding KI to the MOLE-containing samples enhanced the inhibitor's adsorption. The SEM-EDX observations supported the findings from electrochemical characterization and confirmed MOLE’s high inhibition performance. Hence, this study suggests that MOLE has promising potential as a green corrosion inhibitor for the API 5L X52 steel in acidic media.

Investigation of the corrosion inhibition performance of snail slime on the exposed surface of mild steel in acidic environment

Corrosion of metals is a major issue in various industries and the use of organic materials, especially plant extracts, as alternatives to toxic chemicals in corrosion inhibitors is gaining attention. However, the potential of animal products as corrosion inhibitors has not been fully explored. This study investigates the corrosion inhibiting potential of snail slime (SS) for mild steel in 0.5 M H2SO4 solution using Gravimetric and electrochemical methods, including open circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used for material characterization. The results indicate that snail slime has a high inhibition efficiency of up to 92.75%, with inhibition efficiency decreasing as temperature and immersion time increase but it increased with higher inhibitor concentrations. Adsorption studies showed that snail slime exhibited strong adherence to the Langmuir and Temkin adsorption isotherms, indicating spontaneous adsorption on mild steel. The inhibition mechanism shows typical physical adsorption and follows first-order kinetics. While the EIS analysis indicated a charge transfer-controlled corrosion process with the highest inhibition efficiency of 81.74%, the PDP analysis revealed that snail slime acted as a mixed-type inhibitor with the highest inhibition efficiency of 81.98%. FTIR reveals the functional groups responsible for the inhibition exhibited by snail slime inhibitors, including CH, OH, CO-O, CCl, and NH. SEM shows that the inhibition of corrosion is due to the formation of an insoluble stable protective film on the sample surface by an adsorption process. These findings suggest that snail slime has significant potential as an eco-friendly alternative to synthetic corrosion inhibitors in industrial applications.