Mechanism Of Inhibition Research Articles

The fine structural changes of phenolic hydroxyl groups of cinnamic acid and its derivatives affects their inhibition mechanism and interaction with α-glucosidase

Cinnamic acid (CCA), p-coumaric acid (PCA), and caffeic acid (CA) are natural phenolic compounds and extensively utilized in the food industry. PCA and CA are both derivatives of CCA and share comparable molecular structures. In this study, the inhibitory mechanisms of CCA, PCA, and CA on α-glucosidase was investigated by employing inhibition kinetics and molecular docking analyses. Our results revealed that CCA (IC50 = 6.12 ± 0.056 mM) and CA (IC50 = 2.02 ± 0.083 mM) exhibited mixed-type inhibition, while PCA (IC50 = 3.82 ± 0.095 mM) exhibited non-competitive inhibition. The intermolecular energy values of CCA, PCA, and CA with α-glucosidase were determined to be −7.11, −7.94, and −8.14 kcal/mol, respectively, indicating their binding to α-glucosidase via hydrophobic interactions and hydrogen bonding, among which CA has the greatest binding ability. Fluorescence quenching results and circular dichroism (CD) spectra further confirmed the higher affinity of CA to α-glucosidase than that of CCA and PCA. These outcomes shed light on the importance of molecular structure differences in α-glucosidase inhibition and highlight the potential scope for developing low-glycemic-index functional foods.

New insights into the reduction of protein degradation in freshwater fish by proanthocyanidins: Inhibition mechanism and the conformational changes of endogenous cathepsin B

New insights into the reduction of protein degradation in freshwater fish by proanthocyanidins: Inhibition mechanism and the conformational changes of endogenous cathepsin B

Computational Insights Into the Mechanism of EGCG's Binding and Inhibition of the TDP-43 Aggregation.

Misfolding and aggregation of TAR DNA-binding protein, TDP-43, is linked to devastating proteinopathies such as ALS. Therefore, targeting TDP-43's aggregation is significant for therapeutics. Recently, green tea polyphenol, EGCG, was observed to promote non-toxic TDP-43 oligomer formation disallowing TDP-43 aggregation. Here, we investigated if the anti-aggregation effect of EGCG is mediated via EGCG's binding to TDP-43. In silico molecular docking and molecular dynamics (MD) simulation suggest a strong binding of EGCG with TDP-43's aggregation-prone C-terminal domain (CTD). Three replicas, each having 800 ns MD simulation of the EGCG-TDP-43-CTD complex, yielded a high negative binding free energy (ΔG) inferring a stable complex formation. Simulation snapshots show that EGCG forms close and long-lasting contacts with TDP-43's Phe-313 and Ala-341 residues, which were previously identified for monomer recruitment in CTD's aggregation. Notably, stable physical interactions between TDP-43 and EGCG were also detected invitro using TTC staining and isothermal titration calorimetry which revealed a high-affinity binding site of EGCG on TDP-43 (Kd, 7.8 μM; ΔG, -6.9 kcal/mol). Additionally, TDP-43 co-incubated with EGCG was non-cytotoxic when added to HEK293 cells. In summary, EGCG's binding to TDP-43 and blocking of residues important for aggregation can be a possible mechanism of its anti-aggregation effects on TDP-43.

Study on cooling efficiency and mechanism of lithium-ion battery thermal runaway inhibition by additives enhanced water mist based on boiling heat transfer theory

In recent years, fire and explosion accidents caused by thermal runaway (TR) of lithium-ion batteries (LIB) have occurred frequently, which has become one of the main obstacles restricting its development. Therefore, it is urgent to develop fire extinguishing agents with high cooling efficiency to inhibit the growth of TR. The water mist is an effective choice, but it shows poor performance with the rise in cell temperature under TR. In this study, two additives, KCl and the nonionic fluorocarbon surfactant FC-4430, were added to the water mist to improve the cooling efficiency. In addition, the inhibition effect exerted by the modified water mist during the whole process of lithium-ion battery TR was experimentally investigated. Furthermore, the influence of water mist with additives on the Leidenfrost effect in the high temperature range was deduced, and the reinforcement cooling mechanism was analyzed by heat transfer theory. The results show that KCl and FC-4430 can increase the initial cooling rate in the high temperature range by 48.6%–120%. The reinforcement mechanism is attributed to changing the medium's physical parameters with additives. On the one hand, the Leidenfrost point of the droplets on the cell surface is increased, which in turn extends the temperature range of the nucleate boiling stage, and on the other hand, the heat flux density and heat transfer of the water mist in the film boiling state are increased.

Preparation of zwitterionic polymer and its application for dual-functional inhibition in deepwater drilling

During deep-water drilling operations, due to the conditions with low temperature and high pressure in the wellbore, methane hydrate can be easily formed in the presence of methane and plug the wellbore. In addition, the deep-water sediments are dominated by clay-silty with weak cementation, so well instability may be occurred due to clay hydration. In order to inhibit hydrate formation and clay hydration in deepwater drilling, a zwitterionic polymer AADV was synthesized through quaternary copolymerization of AM/AMPS/DMDAAV/VAC. The hydrate inhibition performance of AADV was evaluated in a high-pressure reactor chamber, and the results showed that AADV can delay the hydrate formation time from 330 min in pure water to 2204 min, indicating an excellent inhibition effect of hydrate formation. Meanwhile, 1 % AADV can significantly reduce the linear swelling rate of the calcium-based bentonite to 3.69 % for 10 h and increase the rolling recovery rate to 94.7 %, suggesting an excellent inhibition effect on clay hydration. The mechanism of dual-functional inhibition of AADV was further analyzed. The zwitterionic group in AADV and the hydrophilic amide group can strongly adsorb the water molecules through a strong hydration effect and the hydrogen bonding effect, respectively, which contributes to destroy the water molecules cage structure, and thus to suppress the hydrate formation. Besides, AADV can effectively obstruct mass transfer of methane molecules by increasing the viscosity of the aqueous phase and absorbing on the hydrate surface, leading to hydrate formation inhibition. For the inhibition of clay hydration, the SEM and XRD results proved that AADC inhibits the clay hydration through the film-forming effect. In addition, the contact angle of Na-Bent/AADC composite reached to 55.68° when the polymer concentration increased to 2 %, suggesting that the hydrophobicity of Na-Bent surface can be enhanced after AADC treatment. AADV can wrap around clay particles and form hydrophobic film through adsorption and intercalation, preventing the intrusion of external fluids and inhibiting clay hydration.

How does the integration of amino acids enhance the bonding ability of triazine-based inhibitors with iron surfaces: Insights from SCC-DFTB, COSMO-RS and molecular dynamics simulations

Theoretical investigations into the adsorption of molecules on metal surfaces play a pivotal role in the development of more efficient corrosion inhibitors. This study offers a novel approach by combining Density Functional Tight Binding (DFTB), Molecular Dynamics (MD) simulations, and conductor-like screening model for realistic solvation (COSMO-RS) calculations to comprehensively assess the interaction and diffusion properties of glycine (Gly), 2,2′-azanediyldiacetic acid (IDA), and 5-aminopentanoic acid (5-APA) with two 1,3,5-triazine (Tris) derivatives (Tris-Gly and Tris-IDA) for corrosion protection of carbon steel in acidic medium. The solvation properties of these molecules were evaluated alongside their interaction strength with the Fe(1 1 0) surface, considering both neutral and protonated forms. DFTB simulations revealed a clear trend in interaction energies, following the order: Tris-IDA > Tris-Gly > 5-APA > IDA > Gly. It ranges from −1.191 eV to −1.853 eV, with the highest stability observed for protonated Tris-IDA (−1.853 eV), while neutral Glycine exhibits the lowest interaction energy (−1.263 eV). While these theoretical results diverged slightly from experimental observations, with Tris-Gly outperforming Tris-IDA, this discrepancy was attributed to steric effects and solvent interactions. The DFTB results also indicated strong covalent interactions, particularly involving acetic groups, between the inhibitors’ orbitals and the iron’s 3d orbitals. MD simulations further demonstrated the impact of protonation on inhibitor mobility, with reduced diffusion coefficients due to enhanced electrostatic interactions and hydrogen bonding. COSMO-RS solvation analysis confirmed the strong hydrogen bonding capabilities of these molecules with water. Overall, this study elucidates the mechanisms of corrosion inhibition by integrating multiple simulation techniques, providing key molecular insights that can guide the design of more effective corrosion inhibitors. The findings emphasize the significance of electronic interactions and molecular structure in enhancing inhibitor performance, making this a valuable contribution to corrosion science.

Folate-Functionalized Chitosan-PLGA Nanoparticles: A Novel approach for targeted osthole delivery in pancreatic cancer

Efficient drug delivery systems targeting cancer cells are crucial for enhancing cancer therapy. In this study, we developed PLGA nanoparticles coated with folate-conjugated chitosan (osthole-PLGA-NPs/CS-FA) to deliver osthole to cancer cells and investigated its inhibitory and molecular signaling mechanisms in the PANC-1 pancreatic cancer cell line. Field emission scanning electron microscopy (FESEM) revealed that osthole-PLGA-NPs/CS-FA had a spherical structure with a uniform size distribution. Dynamic light scattering (DLS) analysis showed an average size of 171.76 nm, a dispersion index 0.26, and a surface charge of + 33.08 mV, indicating stability and uniform dispersion. Fourier-transform infrared (FTIR) spectrum analysis confirmed the successful incorporation of osthole into the PLGA nanoparticles, with an encapsulation efficiency of 93.12 %. These physicochemical properties suggest efficient cellular uptake and targeted delivery. The antioxidant potential of osthole-PLGA-NPs/CS-FA was evaluated using the ABTS assay, showing concentration-dependent inhibition of free radicals with an IC50 value of 172.95 μg/mL. The anticancer properties were assessed using the MTT assay, demonstrating a significant and concentration-dependent cytotoxic effect on PANC-1 cells (IC50 = 31.2 μg/mL) with minimal impact on normal human foreskin fibroblast (HFF) cells. DAPI staining and flow cytometry analyses confirmed a concentration-dependent increase in apoptosis in PANC-1 cells. The nanoparticles induced upregulation of Bax and downregulation of Bcl2, indicating activation of the intrinsic mitochondrial apoptotic pathway. The anti-angiogenic activity of osthole-PLGA-NPs/CS-FA was evaluated using the chick chorioallantoic membrane (CAM) assay. The results showed significant inhibition of angiogenesis in a concentration-dependent manner, starting at 40 μg/mL and increasing up to 120 μg/mL. In conclusion, osthole-PLGA-NPs/CS-FA nanoparticles exhibit promising potential for targeted pancreatic cancer therapy by enhancing cellular uptake, inducing apoptosis, and inhibiting angiogenesis.

Hydrolytic polymaleic acid: An environmentally friendly inhibitor for the flotation separation of parisite from calcite and fluorite

Hydrolytic polymaleic acid (HPMA) was used as a highly selective depressant instead of water glass to achieve the flotation separation of parisite from calcite and fluorite. The inhibitory effect and mechanism of HPMA on fluorite and calcite was investigated using micro-flotation, zeta potential, contact angle measurements, adsorption measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and quantum chemical calculations. The results from single and artificially mixed minerals showed that parisite could be successfully separated from calcite and fluorite by using HPMA as a depressant. Further analysis revealed that HPMA chemically adsorbed onto the Ca2+ active sites of calcite and fluorite, forming a hydrophilic compound, Ca(COOR), which prevented the octyl hydroxamic acid (OHA) collector adsorbing on their surfaces. In contrast, HPMA only weakly physically adsorbed onto the surface of parisite, allowing it to maintain good floatability after conditioning with HPMA. Therefore, HPMA has a potential as an inhibitor for effectively separating parisite from fluorite and calcite in rare earth ore flotation process.

Investigation on the inhibition effect and mechanism of hydrogen explosion by 2-bromo-3,3,3-trifluoropropene

This study investigated the effect of 2-bromo-3,3,3-trifluoropropene (2-BTP, C3H2BrF3) on hydrogen explosion behavior through a combination of experiments and simulations. The maximum explosion pressure (pmax), maximum pressure rise rate ((dp/dt)max), and critical inhibition concentration (CIC), across different equivalence ratios (Φ) and inhibitor concentrations (V), were obtained via experiments. The changes in adiabatic flame temperature, mole fraction of active radicals and sensitivity coefficient throughout the reaction were analyzed using CHEMKIN. The fuel-like properties of 2-BTP and the carbon monoxide (CO) produced by decomposition led to a promoting effect on the lean hydrogen explosion, primarily due to the elementary reactions R31, R806 and R882. When Φ≥1.0, the capture of active radicals via elementary reactions such as R908, R1507, and R88 was enhanced, resulting in the dominance of inhibition and a corresponding inhibitory effect. Notably, 2-BTP exhibited an inhibitory effect for (dp/dt)max at any equivalence ratio. The CIC decreased from 10% to 4% when increasing equivalence ratios from 0.6 to 2.0. This work provides crucial data and a theoretical foundation for the prevention and control of hydrogen explosions.

Investigating the impact of active PHBV films on the nutritional quality of minimally processed apples

The aim of the study was to study the effect of an active film, a blend of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with a derivative of ferulic acid known as bis-O-dihydroferuloyl-1,4-butanediol (BDF), on the quality decay kinetic of minimally processed apples. Due to its properties, BDF is a promising candidate to serve both as a non-toxic biobased plasticizer and as an active additive, simplifying formulation of active packaging. Molecular modelling studies were conducted to explore the interaction between polyphenol oxidase (PPO) and BDF molecule, with the aim of understanding the mechanism of inhibition. The apple slices packed in different treatments exhibited an increase in PPO activity; however, the samples packed in active films showed a significantly slower rate of PPO activity (P < 0.05). Almost 50% of the ascorbic acid content degraded in the control samples (4.95–4.97 mg/100 g fruit weight (FW)) at d7 compared with the samples packaged in BDF-releasing films (5.81–6.1 mg/100 g FW) in which the degradation was only 30%. Using molecular modelling, it was observed that BDF (−6.3 kcal/mol) exhibited a stronger interaction with PPO than catechol (−4.5 kcal/mol) in the met and oxy states. BDF-releasing films showed superior preservative potential over the control as BDF competitively inhibits the PPO active site due to π–π stacking between the aromatic cycle of the BDF molecule and the PHE259 and hydrogen bonding with the active site.

Synergistic effect of the combination of phenolic compounds and tobramycin on the inhibition of Pseudomonas aeruginosa biofilm

Bacteria coordinate gene expression in a cell density-dependent manner using a communication process called quorum sensing (QS). The expression of virulence factors, biofilm formation and enzyme production are examples of QS-regulated phenotypes that can interfere with food quality and safety. Due to the importance of these phenotypes, the inhibition of bacterial communication as an anti-virulence strategy is of great interest. This work aimed to evaluate the effect of phenolic compounds on the inhibition of biofilm formation by Pseudomonas aeruginosa PAO1, using concentrations that do not interfere in bacterial growth. The synergistic effect of rosmarinic acid, baicalein, curcumin and resveratrol with tobramycin and between the phenolics themselves was evaluated. The tested combinations proved to be a good strategy for reducing the dose of antibiotics used in treatments and obtaining satisfactory results against P. aeruginosa biofilms. The combination of the four compounds at the highest concentration (500 μM) completely inhibited biofilm formation. The obtained results contribute to understanding the effect of phenolic compounds on QS inhibition, which may help to define the mechanism of inhibition, in addition to expanding the biotechnological potential of these compounds for future applications in the food, pharmaceutical and medical fields.

Inhibitory effects of polyphenols on the Maillard reaction in low lactose milk and the underlying mechanism

In this study, low lactose milk (LLM) was heat-treated under different conditions and stored at 4, 25 and 37°C for 15 d, after which the changes in the Maillard reaction (MR) of LLM were investigated. The contents of α-dicarbonyl compounds and 5-hydroxymethylfurfural(5-HMF) in LLM after the addition of polyphenols were determined via HPLC, and the inhibitory effects of 3 different concentrations of epigallocatechin gallate (EGCG), dihydromyricetin (DMY), and procyanidin (PC) on the MR of LLM were studied. The fluorescence intensity of LLM was measured at 290, 300 and 310 K, the fluorescence quenching types and binding constants of PC on casein were investigated, and thermodynamic analysis was carried out. These results suggest that the optimal heat treatment conditions were 80°C for 15 s and that the optimal storage conditions were 4°C. In the α-dicarbonyl compound capture and 5-HMF inhibition tests, PC had the greatest inhibitory effect at a concentration of 0.2 mg/mL, with an inhibition rate of 48.19%. Therefore, PC is more stable than the other 2 polyphenols. The mechanism of inhibition involves the formation of matrix complexes between PC and casein in LLM, resulting in static quenching of the LLM and thus a reduction of the inhibitory effect. The thermodynamic analysis revealed that the binding of PC to casein was an exothermic reaction, and the combination of the 2 was driven mainly by hydrogen bonding and van der Waals forces. This study lays a theoretical foundation for the development of LLM.

NaCl inhibits Geotrichum citri-aurantii growth by inducing lipid droplets accumulation and enhances the biocontrol efficacy of Kloeckera apiculata 34-9

Decays resulting from infections by Geotrichum citri-aurantii cause a significant reduction in citrus postharvest quality and marketable yield. In the present work, 0.8 mol · L-1 NaCl of Generally Recognized as Safe (GRAS) salts were identified to have complete inhibition activity to G. citri-aurantii in vitro and in vivo. An inhibitory mechanism study showed that 0.1 mol · L-1 NaCl changed the expression of six genes (Gci002087, Gci003354, Gci000013, Gci000394, Gci003505 and Gci004433) in target of rapamycin (TOR) pathway, thus inducing a large number of lipid droplets (LDs) accumulation with TEM observations and staining. In vivo, 0.1 mol · L-1 NaCl could raise up the activities of CAT, PAL, PPO and cellulase which hence to strengthen the ability of resistance tolerance of citrus. In addition, NaCl not only accelerated the growth of the biocontrol yeast Kloeckera apiculata strain 34-9, but also increased the expression level of adhesin-encoding genes and biofilm-formation encoding gene (34-9 - 3691). Finally, the storage experiments in 3 months demonstrated that the combination of NaCl and the yeast 34-9 could keep fresh, reduce decay and prolong its shelf-life, thus implying that the combination of biocontrol strain and GRAS salts has been explored as a promising alternative to synthetic fungicides.

Exploring the anti-diabetic activity of 2,6-diamino-4-chloropyrimidinium-hydrogen oxalate conjugates: Synthesis, crystal structure, quantum computational, drug-likeness, molecular docking and dynamics simulation

Inhibiting carbohydrate-hydrolyzing enzyme has been considered as an effective approach for controlling starch digestion and postprandial blood glucose level. The aim of this study, the salt molecule was prepared to identify potentially effective compound against diabetic activity and discover the inhibitory mechanism of the targeted enzyme, which is determined by In-silico techniques. And also perform the quantum chemical calculation to provide insights about the internal motions of the molecule at the atomic level. The 2,6-diamino-4-chloropyrimidinium-hydrogen oxalate (C4H6ClN4+. C2HO4-) was newly synthesized molecule, which is detailly discussed in this present work. The title compound has been confirmed by single-crystal X-ray diffraction studies, and this structure was refined by the least-square refinement method. The crystal compound exhibited the P-1 space group (centrosymmetric) and the following unit cell parameters: a = 5.5778(6)Å, b = 9.6687(10)Å, c = 9.9144(10)Å, α = 116.342(1) °, β = 92.610(1) °, γ = 106.370(1) °, Z = 2. The molecular structure is stabilized by the networks of N–H···O, O–H···O, C–H···O, and N–H···N hydrogen bond interactions. The Hirshfeld surface (HS) analysis and fingerprint plots revealed strong intermolecular interaction between the molecules. The structural optimization, frontier molecular orbital (FMO), molecular reactivity, molecular electrostatic potential (MEP), and mulliken atomic charges were generated by the density functional theory (DFT) calculated at B3LYP/6-311G++ (d,p) theory level. Drug-likeness and physicochemical properties were predicted. The molecular docking analysis was showed a binding energy of −8.96 kcal/mol within the active site of alpha-amylase, which is responsible for anti-diabetic activity. The protein-ligand complex stability was verified using molecular dynamics studies with 100 ns.

Preparation and characterization of moringin-loaded chitosan-coated liposomes and their antibacterial activity against Staphylococcus aureus

This study aimed to improve the stability of moringin and clarify the inhibitory mechanisms of moringin-loaded chitosan-coated liposomes (MR-CS-LPs) against Staphylococcus aureus. Optimisation of MR-CS-LPs was conducted using the response surface methodology, and extensive characterization was performed. The anti-bacterial activity of MR-CS-LPs was assessed by determining the minimum inhibitory concentration (MIC) and conducting growth curve analyses. The effects of MR-CS-LPs on S. aureus cell wall and membrane integrity were investigated using techniques such as scanning electron microscopy and physical and chemical analyses. Apoptotic effects were evaluated by examining oxidative stress parameters, and the impact on S. aureus biofilm formation was explored. An LC–MS/MS analysis provided insights into the inhibitory mechanism of MR-CS-LPs against S. aureus. The results indicated that MR-CS-LPs achieved an encapsulation rate of 69.02 %. Furthermore, they demonstrated potent anti-bacterial activity against S. aureus, with an MIC of 0.125 mg/mL. MR-CS-LPs disrupted cell wall and membrane integrity, resulting in macromolecule leakage, induced oxidative stress–mediated apoptosis and effectively suppressed biofilm formation, ultimately leading to bacterial death. Metabolomics analysis revealed that MR-CS-LPs inhibit S. aureus by regulating pyruvate pathways. These findings affirm that MR-CS-LPs possess significant anti-microbial properties, underscoring their potential as effective anti-microbial agents against S. aureus.

Data-Independent Acquisition Proteome Technology for Analysis of Antifungal and Anti-aflatoxigenic Properties of Eugenol to Aspergillus flavus.

Several toxicogenic Aspergilli, such as Aspergillus flavus and A. parasiticus, could biosynthesize aflatoxin B1 (AFB1) and other mycotoxins. Chemical fungicides are commonly used to control fungal contamination, but chemical residues may pose significant risks to human health and environmental stability. Consequently, natural antifungal and aflatoxin-inhibiting agents could be sustainable alternatives. Eugenol has been used as an inhibitor of aflatoxins (AFs), which is a common essential oil. Nevertheless, the definite mechanism by which eugenol exerts its inhibitory effect on Aspergillus remains unclear. This research demonstrates that eugenol significantly suppressed fungi growth and AF production as the dose increased (40.9 to 100%). With the proteomics approach, the inhibition pathway of eugenol was investigated. The production of proteins involved in cell wall integrity was notably reduced under eugenol treatment, indicating that eugenol destroys the cell wall integrity of A. flavus. Furthermore, exposure to eugenol downregulated several fungal developmental regulators and subsequently inhibited A. flavus development. Energy metabolism in A. flavus is closely related to its secondary metabolism. Under eugenol treatment, the synthesis of proteins relevant to the pentose phosphate pathway was significantly enhanced, leading to a decrease in the availability of acetyl-CoA, a precursor for AF biosynthesis. Simultaneously, the valine, leucine, and isoleucine biosynthesis pathways were enhanced, further reducing the content of acetyl-CoA. This might be the primary factor in the inhibition of AF biosynthesis by eugenol. Ribosome biogenesis was the most dysregulated pathway based on KEGG data, indicating that eugenol disturbed ribosome biogenesis and affected its normal function in A. flavus. In conclusion, eugenol inhibits the cellular integrity, energy metabolism, and protein synthesis and then suppresses A. flavus development and AF biosynthesis, which provides a clearer grasp of the inhibitory mechanism meaningful for A. flavus and AF contamination control.

The Performance of Amino‐ and Hydroxy‐Substituted Benzothiazoles in Inhibiting the Corrosion of Carbon Steel in HCl and the Molecular‐Level Mechanisms

AbstractIn the pickling process and acidizing program for oil wells, the acidic corrosion of metals is a problem that needs to be addressed. Various acid corrosion inhibitors have been studied and used to mitigate the acidic corrosion of carbon steel. In this paper, the corrosion inhibition of 2‐aminobenzothiazole (2 N‐BT), 2‐amino‐4‐hydroxybenzothiazole (2 N4O‐BT), and 2‐amino‐6‐hydroxybenzothiazole (2 N6O‐BT) on carbon steel in 0.5 mol/L HCl was investigated using electrochemical and quantum chemical methods. All three molecules exhibited corrosion inhibition effects. Compared to 2 N‐BT, 2 N4O‐BT and 2 N6O‐BT showed less sensitivity to the environmental conditions and the surface state of the metal. Among them, 0.0010 mol/L 2 N6O‐BT demonstrated the highest and most persistent corrosion inhibition, exhibiting a mixed inhibition mechanism with cathodic inhibition dominance. The adsorption of 2 N6O‐BT on the carbon steel surface was found to be non‐uniform, preferentially adsorbing at certain active sites on the surface, following Freundlich‐Langmuir thermodynamic characteristics. It showed initial strongly adsorbed points and weakly adsorbed regions. With continued adsorption of 2 N6O‐BT, the differences between strongly adsorbed points and weakly adsorbed regions decreased. The introduction of hydroxyl groups, especially in 2 N6O‐BT, extended the negative potential region and enhanced the coordination activity of the molecule, generating the orbital distribution that was advantageous to flat adsorption and the formation of feedback bonds. This provided a molecular structural basis for the excellent corrosion inhibition properties of 2 N6O‐BT.

Phase change materials as hydrogen explosion suppressants: An experimental and kinetic investigation

To investigate the potential application of phase change materials as H2 explosion suppressants, in the present work, the inhibition effect of Na2HPO4·12H2O, K2HPO4·3H2O, and Na2CO3·10H2O on H2 explosion were experimentally studied. The corresponding explosion suppression mechanism was calculated by using a comprehensive combustion model. Results showed that the selected phase change materials inhibited the H2 explosion, and Na2CO3·10H2O has the most significant effect for fuel-lean H2-air mixtures when 12 g was added. Of which the maximum explosion pressure (Pmax) and maximum rate of pressure rise (dp/dt)max were reduced by 26.6 % and 28.1 %, and maximum pressure increase time (tb) and peak pressure time(tc) were increased by 112.2 % and 120.3 %. The inhibition mechanism of Na2CO3·10H2O on H2 was revealed by numerical simulation. The adiabatic flame temperature (AFT) and laminar burning velocity (LBV) of H2-air mixture decrease with increasing hydrated salt addition, the free radicals H, O and OH have a decisive influence on the explosion process during which H decreases by 86.4 % at most. The chain initial reaction O + H2 ⇌ H + OH and the sodium-containing primitive reaction NaO + H + M ⇌ NaOH + M have the most significant influence on the combustion processes. The results of present work give a theoretical foundation for application the phase change materials in H2 explosion safety industry.

Optimizing biosurfactant structure: Experimental and theoretical investigation of the influence of hydroxyl groups on sour corrosion mitigation

Oil and natural gas remain crucial for meeting global energy demands, but their extraction and processing face significant challenges due to sour corrosion. This study explores the influence of hydroxyl groups on the performance of biosurfactants, specifically sorbitol oleate (SOCI) and pentaerythritol oleate (POCI), in sour environments. This study reveals that the presence of more hydroxyl groups in inhibitor molecules significantly enhances their effectiveness against sour corrosion. A weight loss study showed that the corrosion rates dropped to 0.033 mm/y for POCI and 0.005 mm/y for SOCI from an initial rate of 0.490 mm/y in the blank solution, indicating the superior inhibition efficiency of SOCI (98.9 %) compared to POCI (93.3 %) at 24 × 10−4 M. Electrochemical measurements corroborated these findings, demonstrating increased corrosion resistance and reduced current densities in the presence of both inhibitors, with SOCI exhibiting better performance. The inhibition mechanism involves a combination of physical and chemical adsorption. Density functional theory calculations indicated the role of hydroxyl groups in enhancing adsorption and corrosion inhibition efficiency, with SOCI exhibiting a smaller energy gap, lower hardness, and higher softness compared to POCI. MD simulations confirmed the stable adsorption of both inhibitors on the Fe (110) surface, with SOCI showing a more favorable orientation and stronger interaction due to its higher number of hydroxyl groups. This facilitates stronger adsorption on the CS surface and the formation of a more robust protective film. The combined experimental and computational findings highlight the importance of molecular structure, film-forming ability, and hydroxyl content for the design and development of next-generation hydroxyl-rich biosurfactants for mitigating sour corrosion in the oil and gas industry.

Exploring the binding mode of phenyl and vinyl boronic acids to human carbonic anhydrases

Boronic acids are an interesting but still poorly studied class of carbonic anhydrase inhibitors. Previous investigations proved that derivatives incorporating aromatic, arylalkyl, and arylalkenyl moieties are low micromolar to millimolar inhibitors for several α- and β-CAs involved in pathologic states.Here we report a high-resolution X-ray study on two classes of boronic acids (phenyl and vinyl) in complex with hCA II. Our results unambiguously clarify the binding mode of these molecules to the human carbonic anhydrase active site, which occurs through their tetrahedral anionic form, regardless of the nature of the organic scaffold. Data here presented contribute to the understanding of the inhibition mechanism of boronic acids that can be fruitfully used for the rational design of novel and effective isozyme-specific carbonic anhydrase inhibitors.