Acidic Ones Research Articles

Boosting alkaline hydrogen evolution via in-plane heterostructure construction with Ultra-Exposed heterointerfaces

Enhancing the catalytic efficiency of molybdenum disulfide (MoS2) towards the hydrogen evolution reaction (HER) is valuable for water electrolysis technology. This study fabricated a novel Co2P@1T-MoS2 “in-plane” heterostructure as a catalyst for alkaline HER. In this heterostructure, the Co2P nanoclusters are dispersed within the 1 T-MoS2 nanosheet. Remarkably, the coexistence of Co2P and 1 T-MoS2 phases within the same plane maximizes the exposure of interfacial active sites. The interfacial interaction between Co2P and 1 T-MoS2 facilitates water dissociation and hydrogen adsorption. This results in outstanding catalytic activity with a small overpotential of 37 mV at a current density of 10 mA cm−2 in 1.0 M KOH. Intriguingly, the Co2P@1T-MoS2 heterostructure exhibits higher activity in alkaline electrolytes compared to acidic ones. The difference in active sites for hydrogen adsorption (Co versus S) in distinct electrolytes is believed to be the underlying reason for this “abnormality”.

In Ukrainian

The paper discusses the results of saponite research from the Tashkiv deposit of Ukraine. X-ray structural analysis proved the necessity of preliminary cleaning of saponites from mineral impurities. The study of the morphology, nanoprofile and topography of the surface of saponite by the methods of SEM-microscopy and Atomic Force Microscopy revealed that the mineral is represented by aggregates of nano- and microparticles of a pyramidal shape. Its characteristic feature is the heterogeneity of isomorphic substitutions of ions in the tetrahedral and octahedral sheets of the structural elementary package. According to X-ray fluorescence analysis, saponite contains a significant amount of Fe3+, which isomorphically replaces magnesium Mg2+ and, accordingly, is located mastly in the octahedral sheet of the structural package with a charge from +0.37 to +0.35. The number and mechanism of isomorphic substitutions determine the presence of a total negative charge of the crystal lattice (from –0.38 to –0.3), the value of which ensures intensive interaction with water molecules of the interpacket space with the formation of surface OH groups. Accordingly, both acidic and alkaline Lewis and Brønsted centers are present on the surface with a predominance of acidic ones, so the acidity function is 5.82, and the point of zero proton charge is pH = 5.5. During dispersion in water, a part of the alkaline centers of the side surface are transformed into Brønsted acid centers as a result of their protonation, which causes an increase in the pH of the dispersion medium to pH = 8–8.6. Accordingly, the isoionic state is reached at pH = 7.5. The difference in pH values characterizing the isoionic state of the surface and the point of zero net proton charge (PZNPC) indicates the presence of weak acid-alkaline centers on the surface. The study of the adsorption of acid-alkaline dyes showed the adsorption of alkaline (pK = 1¸3) and acid (pK = 7¸14) dyes on saponites. The latter is significantly reduced due to the preliminary hydration of the solid surface - mainly the lateral edges of the particles. Acidic dyes are not adsorbed from a dispersion medium with pH < 5.5 (PZNPC), and basic dyes are adsorbed at pH > 5,5( PZNPC).

Euglena gracilis Protein: Effects of Different Acidic and Alkaline Environments on Structural Characteristics and Functional Properties.

Due to the growing demand for human-edible protein sources, microalgae are recognized as an economically viable alternative source of proteins. The investigation into the structural characteristics and functional properties of microalgin is highly significant for its potential application in the food industry as an alternative source of protein. In this research, we extracted protein from Euglena gracilis by using alkaline extraction and acid precipitation and investigated its structural characteristics and functional properties in different acidic and alkaline environments. The molecular weight distribution of Euglena gracilis protein (EGP), as revealed by the size exclusion chromatography results, ranges from 152 to 5.7 kDa. EGP was found to be rich in hydrophobic amino acids and essential amino acids. Fourier infrared analysis revealed that EGP exhibited higher α-helix structure content and lower β-sheet structure content in alkaline environments compared with acidic ones. EGP exhibited higher foaming properties, emulsifying activity index, solubility, free sulfhydryl, and total sulfhydryl in pH environments far from its isoelectric point, and lower fluorescence intensity (2325 A.U.), lower surface hydrophobicity, larger average particle size (25.13 µm), higher emulsifying stability index, and water-holding capacity in pH environments near its isoelectric point. In addition, X-ray diffraction (XRD) patterns indicated that different acidic and alkaline environments lead to reductions in the crystal size and crystallinity of EGP. EGP exhibited high denaturation temperature (Td; 99.32 °C) and high enthalpy (ΔH; 146.33 J/g) at pH 11.0, as shown by the differential scanning calorimetry (DSC) results. The findings from our studies on EGP in different acidic and alkaline environments provide a data basis for its potential commercial utilization as a food ingredient in products such as emulsions, gels, and foams.

Preparation of Activated Biocarbons from Cones and their Potential Application for Adsorption of Antibiotics (Tetracycline).

The pine cones (PC), spruce cones (SC) and fir cones (FC) were used for biocarbons preparation. Chemical activation with sodium hydroxide was applied to prepare activated biocarbons. All the materials under investigation were characterized by the N2 adsorption, scanning electron microscopy (SEM), elemental analysis (CHNS), infrared spectroscopy (ATR FT-IR), and the Boehm's titration method. Moreover, pHpzc (the point of zero charge) was determined. It was shown that cones are a good, cheap precursor from which biocarbons with a developed porous structure, characterized by good adsorption properties, can be obtained. All the obtained adsorbents are characterized mainly by a microporous structure. Moreover, they contain both acidic and basic surface functional groups (acidic ones prevail over basic ones). The tested activated biocarbons have large specific surface area values ranging from 578 to 1182 m2 g-1. The efficacy of selected materials in the adsorption of an essential contaminant of increasing concern, tetracycline (TC), was investigated. The experimental data were described using the Langmuir and Freundlich adsorption isotherm models. The maximum adsorption capacity of the tested biocarbons ranges from 200 to 392 mg g-1. Thermodynamic studies proved that adsorption is a spontaneous and endothermic process. In summary, economical and environmentally friendly adsorbents were obtained.

Automatic segmentation of lysosomes and analysis of intracellular pH with Radachlorin photosensitizer and FLIM

We report application of the fluorescence lifetime imaging microscopy (FLIM) for analysis of distributions of intracellular acidity using a chlorin-e6 based photosensitizer Radachlorin. An almost two-fold increase of the photosensitizer fluorescence lifetime in alkaline microenvironments as compared to acidic ones allowed for clear distinguishing between acidic and alkaline intracellular structures. Clusterization of a phasor plot calculated from fits of the FLIM raw data by two Gaussian distributions provided accurate automatic segmentation of lysosomes featuring acidic contents. The approach was validated in colocalization experiments with LysoTracker fluorescence in living cells of four established lines. The dependence of photosensitizer fluorescence lifetime on microenvironment acidity allowed for estimation of pH inside the cells, except for the nuclei, where photosensitizer does not penetrate. The developed method is promising for combined application of the photosensitizer for both photodynamic treatment and diagnostics.

Investigation of the Chemiluminescent Reaction of a Fluorinated Analog of Marine Coelenterazine.

Bioluminescence (BL) and chemiluminescence (CL) are remarkable processes in which light is emitted due to (bio)chemical reactions. These reactions have attracted significant attention for various applications, such as biosensing, bioimaging, and biomedicine. Some of the most relevant and well-studied BL/CL systems are that of marine imidazopyrazine-based compounds, among which Coelenterazine is a prime example. Understanding the mechanisms behind efficient chemiexcitation is essential for the optimization and development of practical applications for these systems. Here, the CL of a fluorinated Coelenterazine analog was studied using experimental and theoretical approaches to obtain insight into these processes. Experimental analysis revealed that CL is more efficient under basic conditions than under acidic ones, which could be attributed to the higher relative chemiexcitation efficiency of an anionic dioxetanone intermediate over a corresponding neutral species. However, theoretical calculations indicated that the reactions of both species are similarly associated with both electron and charge transfer processes, which are typically used to explain efficiency chemiexcitation. So, neither process appears to be able to explain the relative chemiexcitation efficiencies observed. In conclusion, this study provides further insight into the mechanisms behind the chemiexcitation of imidazopyrazinone-based systems.

Iodine–β-Cyclodextrin: An Effective Corrosion Inhibitor for Carbon Steel in Sulfuric Acid Solution - Experimental Design and Investigating Thermodynamic Parameters

Widely used across industries, carbon steel is vulnerable to corrosion in aggressive environments, especially acidic ones. Thus, effective methods to mitigate metal corrosion from acids are crucial. Inhibitors are extensively used to prevent corrosion in industries, with the potential for improved protective performance. The design of experiments was employed to determine the optimal conditions for enhancing the inhibitor efficiency of Iodine–β-Cyclodextrin (Iodine/β-CD) in a sulfuric acid solution at temperatures ranging from 20°C to 50°C. The relationship between the factors and responses was established using response surface methodology (RSM), employing regression statistical analysis and probabilistic analysis. A single response was recorded: inhibitor efficiency was determined by measuring weight loss before and after immersion in the inhibitor solution. Thermodynamic parameters were also computed to determine adsorption and activation processes. The statistical analysis revealed that the quadratic models for inhibition efficiencies (IE) were highly significant with a coefficient of multiple regressions R2= 0.997. Further validation of the model indicated a good fit (R2 Adj= 0.994), and the experimentally observed values aligned well with predicted ones, demonstrating a highly significant model with Q2= 0.978. The theoretical efficiency predicted by the RSM model was 88.41%, whereas the efficiency observed during the experimental test procedure with the best-evaluated variables was 82.45%. In conclusion, this paper aims to identify the optimal conditions for employing Iodine–β-Cyclodextrin as a new corrosion inhibitor for carbon steel, utilizing experimental design methods. The results indicate that iodine/β-CD exhibits remarkable corrosion inhibitory properties for carbon steel under specific conditions.

Electroosmosis of viscoelastic fluids in pH-sensitive hydrophobic microchannels: Effect of surface charge-dependent slip length

We analytically investigated the electroosmotic flow characteristics of complex viscoelastic liquids within a charged hydrophobic microchannel, considering the pH and salt concentration-dependent surface charge effects in our analysis. We examined the variation of the electric-double layer (EDL) potential field, the surface charge-dependent slip (SCDS) length, the flow field, the viscosity ratio, and both normal and shear stresses in relation to the bulk pH, bulk salt concentration, and Deborah number of the solution. Our current findings indicate that, under strong flow resistance due to increased electrical attraction on counter ions, a highly basic solution with a high EDL potential magnitude results in a significant decrease in the slip length. Neglecting the effect of SCDS leads to an overestimation of flow velocity, with this overprediction being more pronounced for highly basic solutions. This overestimation diminishes as bulk salt concentration increases, particularly when compared to strongly acidic solutions. Furthermore, a noticeable increase in average velocity is observed as the Deborah number rises for highly basic solutions compared to highly acidic ones. This is attributed to the substantial reduction in apparent viscosity caused by the shear-thinning nature of the liquid at higher shear rates, supported by a larger zeta potential modulated strong electrical force for basic solutions. Additionally, we found that the intensity of shear and normal stresses tends to increase with bulk pH, primarily due to the rise in electric body force at higher zeta potential. These results can potentially inform the design and development of a compact, nonmoving electroosmotic pump for transporting biological species with varying physiological properties, such as solution pH. This technology could be applied in subsequent processes involving mixing, separation, flow-focusing for cell sorting, and other related applications.

Nano-Scale Engineering of Heterojunction for Alkaline Water Electrolysis.

Alkaline water electrolysis is promising for low-cost and scalable hydrogen production. Renewable energy-driven alkaline water electrolysis requires highly effective electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). However, the most active electrocatalysts show orders of magnitude lower performance in alkaline electrolytes than that in acidic ones. To improve such catalysts, heterojunction engineering has been exploited as the most efficient strategy to overcome the activity limitations of the single component in the catalyst. In this review, the basic knowledge of alkaline water electrolysis and the catalytic mechanisms of heterojunctions are introduced. In the HER mechanisms, the ensemble effect emphasizes the multi-sites of different components to accelerate the various intermedium reactions, while the electronic effect refers to the d-band center theory associated with the adsorption and desorption energies of the intermediate products and catalyst. For the OER with multi-electron transfer, a scaling relation was established: the free energy difference between HOO* and HO* is 3.2 eV, which can be overcome by electrocatalysts with heterojunctions. The development of electrocatalysts with heterojunctions are summarized. Typically, Ni(OH)2/Pt, Ni/NiN3 and MoP/MoS2 are HER electrocatalysts, while Ir/Co(OH)2, NiFe(OH)x/FeS and Co9S8/Ni3S2 are OER ones. Last but not the least, the trend of future research is discussed, from an industry perspective, in terms of decreasing the number of noble metals, achieving more stable heterojunctions for longer service, adopting new craft technologies such as 3D printing and exploring revolutionary alternate alkaline water electrolysis.

–HH and –HAAAH motifs act as fishing nets for biologically relevant metal ions in metallopeptides

Histidine are one of the most common residues involved in transition metal ion binding in the active sites of metalloenzymes. In order to mimic enzymatic metal binding sites, it is crucial to understand the basic coordination modes of histidine residues, distributed at different positions in the peptide sequence. We show that: (i) the separation of two histidines has a large effect on complex stability – a sequence with adjusting histidine residues forms more stable complexes with Zn(II) than the one in which the residues are separated, while the contrary is observed for Cu(II) complexes, in which amide nitrogens participate in metal binding. No pronounced effect is observed for Ni(II) complexes, where the amides participate in binding at higher pH; (ii) non-coordinating amino acid residues (basic, acidic and aromatic ones) have a significant impact on complex stability; charged and aromatic residues may enhance Zn(II) binding, while the contrary is observed for the amide-binding Cu(II); (iii) cysteine containing sequences are much more effective Zn(II) and Ni(II) binding motifs at pH above 8, while histidine containing ligands are more suitable for effective Zn(II) and Ni(II) binding at lower pH.

Effect of chemical species and temperature on the stability of air nanobubbles

The colloidal stability of air nanobubbles (NBs) was studied at different temperatures (0–30 °C) and in the presence of sulfates, typically found in mining effluents, in a wide range of Na2SO4 concentrations (0.001 to 1 M), along with the effect of surfactants (sodium dodecyl sulfate), chloride salts (NaCl), and acid/base reagents at a pH range from 4 to 9. Using a nanobubble generator based on hydrodynamic cavitation, 1.2 × 108 bubbles/mL with a typical radius of 84.66 ± 7.88 nm were generated in deionized water. Multiple evidence is provided to prove their presence in suspension, including the Tyndall effect, dynamic light scattering, and nanoparticle size analysis. Zeta potential measurements revealed that NBs are negatively charged even after two months (from − 19.48 ± 1.89 to − 10.13 ± 1.71 mV), suggesting that their stability is due to the negative charge on their surface. NBs were found to be more stable in alkaline solutions compared to acidic ones. Further, low amounts of both chloride and sulfate dissolved salts led to a reduction of the size of NBs. However, when high amounts of dissolved salts are present, NBs are more likely to coalesce, and their size to be increased. Finally, the investigation of the stability of air NBs at low temperatures revealed a non-monotonic relationship between temperature and NBs upon considering water self-ionization and ion mobility. This research aims to open a new frontier towards the application of the highly innovative NBs technology on the treatment of mining, mineral, and metal processing effluents, which are challenging aqueous solutions containing chloride and sulfate species.

A study on the chemical stability of cholesterol-lowering drugs in concomitant simple suspensions with magnesium oxide

BackgroundDifficulty in taking solid medicines is a common issue particularly for the elderly because of a decline in swallowing function, also known as dysphagia. For patients with such a dysfunction, a simple suspension method, in which solid medicines are disintegrated and suspended using warm water, has been developed and widely used in Japanese clinical settings. However, there is little information on drug stability in the simple co-suspension of multiple formulations especially including acidic or alkaline ones. In this study, the chemical stability of typical cholesterol-lowering drugs was investigated in a simple co-suspension with alkaline magnesium oxide (MgO) which is frequently used as a laxative or antacid in Japan.MethodsA cholesterol-lowering drug (one tablet) was soaked with or without MgO in warm water (55°C), and the vessel was left at room temperature for 10 min or 5 h. The suspensions prepared were then analyzed by high-performance liquid chromatography. Degradation products were analyzed by nuclear magnetic resonance spectroscopy and mass spectrometry for the structural elucidation.ResultsIn the simple co-suspension with MgO, no significant degradation was observed for atorvastatin or pravastatin, while a significant decrease of the recovery from the co-suspension was observed for rosuvastatin after 5 h. On the other hand, simvastatin and ezetimibe co-suspended with MgO were partially degraded to simvastatin acid and a pyran compound, respectively.ConclusionsA simple co-suspension with MgO is feasible for atorvastatin, pravastatin, and rosuvastatin, although the rosuvastatin tablet should not be left soaking for a long time. Further it is inadvisable to suspend simvastatin or ezetimibe together with MgO because of their partial degradation.

The atom-efficient production of glycerol carbonate via transesterification between dimethyl carbonate and glycerol over fluorinated Al2O3-ZrO2 solid solution catalysts with suitable acidic-basic property

A series of Al2O3-ZrO2-nF solid solution catalysts (n was the F: Al atomic ratios) with Al: Zr molar ratio of 0.2, was fabricated by addition of varied amounts of (AlF6)3- into the ZrO2 via a co-precipitation method. To our delight, the acidic-basic properties of Al2O3-ZrO2-nF can be tuned by the change of n. Then, the role of acidic-basic sites was investigated for the glycerol carbonate (GLC) production from glycerol and dimethyl carbonate (DMC). Despite that the more basic samples exhibited higher reactivities compared to that of the more acidic ones, the cooperative effect between the acidic-basic pairs can enhance the catalyst activity strongly. So, the catalyst with F/Al= 1.0 can realize the quantitative and selective transformation of glycerol to GLC applying DMC/glycerol of 1:1 ratio with a GLC yield of 91.2%, owing to its appropriate acidic-basic property. Furthermore, the uniform solid solution structure can prevent the generation of free Al or F species, assuring the catalytic material an excellent stability. More importantly, several green parameters including process mass intensity, environmental factor and atom utilization were calculated to confirm the environmental and economic compatibility of the GLC synthesis over the model catalyst.

The Mechanical Stability of Pure Norway Spruce Stands along an Altitudinal Gradient in the Czech Republic

Norway spruce stands are established and managed along various site conditions in central Europe. Currently, spruce often grows at locations outside of its ecological optimum, resulting in extensive damage elicited by harmful abiotic and biotic factors, which relatively shortens the time to change this adverse status in the adaptation frame by foresters. Except for the rapid change in species composition through clear-cuts, another way is possible, i.e., stabilising current (especially young) spruce stands to extend the time required to implement adaptation measures. The assumption that different site conditions will have to be respected as part of this adaptation was confirmed by our study based on NFI data of the Czech Republic. A semiparametric generalized linear model (GAM) was used to model the relationship between the height-to-diameter ratio and forest stand age, differentially considering particular forest vegetation zones. Spruce stands with lower elevations attain a lower stability (expressed by their height-to-diameter ratio; HDR) than those in the mountains. The HDR culminated in lower and middle altitudes in the first half of the rotation period, representing the most critical timing and effectivity of silvicultural measures. Contrary to previous findings, we found higher HDR values at nutrient-rich sites than those at acid ones, especially up to 50–60 years old. Therefore, more research should be devoted to the issue concerning the same thinning regime under different site conditions.

Formulation and characterization of pH-responsive pickering emulsions stabilized by soy protein isolate/nicotinamide mononucleotide complexes for controlled drug release

pH-responsive emulsion stabilizer can be used as an ideal Pickering emulsion type drug embedding and sustained release. However, achieving an optimal balance of particle wettability and size, emulsion stability, and drug encapsulation efficiency remains challenging. This study delves into the potential of soy protein isolate (SPI) and nicotinamide mononucleotide (NMN) complexes as pH-responsive stabilizers for Pickering emulsions, aiming to optimize particle properties, emulsion stability, and drug encapsulation efficiency for biomedical applications. Our findings illustrate that 1.5 wt% NMN concentration yields the optimal SPI/NMN composite particle properties, contributing to enhanced emulsion stability. The stability was further improved at pH 7 with the addition of 0.01 mol/L sodium chloride. SPI/NMN complexes under these conditions formed a unique three-dimensional network within the continuous phase, evidenced by 3D-laser confocal microscopy. Furthermore, at this NMN concentration, the emulsion thermal stability index peaked at 73.2% above the initial value, accompanied by optimal water-holding capacity (82.5%) and surface coverage (89.23%). Exploring drug encapsulation, we observed that 2% ibuprofen dosage in the microspheres results in drug loading and encapsulation efficiencies of 33.5% and 89.6%, respectively. Importantly, the SPI/NMN-embedded ibuprofen exhibited pH-responsive behavior, with increased release in alkaline conditions and reduced release in acidic ones, signifying potential for pH-targeted drug delivery. The SPI/NMN-embedded ibuprofen showed pH-responsive behavior, with enhanced release at alkaline pH values and reduced release under acidic conditions, suggesting potential utility in pH-targeted drug delivery applications.

Unlocking the Secrets: Exploring the Biochemical Correlates of Suicidal Thoughts and Behaviors in Adults with Autism Spectrum Conditions.

Involving 1 million people a year, suicide represents one of the major topics of psychiatric research. Despite the focus in recent years on neurobiological underpinnings, understanding and predicting suicide remains a challenge. Many sociodemographical risk factors and prognostic markers have been proposed but they have poor predictive accuracy. Biomarkers can provide essential information acting as predictive indicators, providing proof of treatment response and proposing potential targets while offering more assurance than psychological measures. In this framework, the aim of this study is to open the way in this field and evaluate the correlation between blood levels of serotonin, brain derived neurotrophic factor, tryptophan and its metabolites, IL-6 and homocysteine levels and suicidality. Blood samples were taken from 24 adults with autism, their first-degree relatives, and 24 controls. Biochemical parameters were measured with enzyme-linked immunosorbent assays. Suicidality was measured through selected items of the MOODS-SR. Here we confirm the link between suicidality and autism and provide more evidence regarding the association of suicidality with increased homocysteine (0.278) and IL-6 (0.487) levels and decreased tryptophan (-0.132) and kynurenic acid (-0.253) ones. Our results suggest a possible transnosographic association between these biochemical parameters and increased suicide risk.

The influence of degradation in different pH buffer solutions on the optical and durability properties of Monocryl suture: (an in vitro study)

The objective of this work is to investigate the hydrolytic degradation of the Monocryl (PGA/PCL) surgical suture in different pH buffer solutions, and its correlation with the structural alterations the material undergoes. To this end, an in vitro degradation study was conducted under acidic (pH = 2), physiological (pH = 7.4), and alkaline (pH = 8.5) conditions at 37 °C, over 25 days. Changes in the swelling rate, structural and mechanical properties of the Monocryl sample with the degradation time were characterized, from which the related degradation mechanism of the material was concluded. Results showed that the structural values of the Monocryl sample were more sensitive in the alkaline medium than the acidic and neutral ones. It exhibited a reduction in birefringence values by 11.5% from the original one in the buffer solution of pH = 8.5, only 4% at pH = 2, and 2.6% at pH = 7.4, after 20 days of degradation durations. Over the same time period, mechanical loss in neutral, acidic, and alkaline media was decreased to 19, 14.9, and 8.3%, respectively. The obtained results revealed that the Monocryl suture exhibits enhanced degradation properties in neutral conditions rather than both acidic and alkaline ones, with a more homogeneous degradation behavior during the degradation process.Graphical abstract

Structure and catalytic performance relationship of ionic liquids as recyclable alcoholysis catalysts for green preparation of ethylene‐vinyl alcohol copolymer

AbstractAlcoholysis is an important reaction for the current industrial production of ethylene‐vinyl alcohol (EVOH) copolymers. Herein, two series of ionic liquids (ILs), acidic and basic ones, were used as eco‐friendly catalysts for alcoholysis of ethylene‐vinyl acetate (EVA) copolymer. The effects of the reaction parameters (catalyst loading, n(CH3OH)/n(Ac) and reaction time), EVA composition, and nitrogen flow on the alcoholysis were systematically investigated. A nearly 100% of alcoholysis degree was achieved using acidic ILs ([BHSO3MIm][HSO4]) under the optimum conditions (3.0 mol% catalyst loading relative to the VA units in EVA, n(CH3OH)/n(Ac) = 30, 70°C, 6 h). Moreover, [BHSO3MIm][HSO4] could be reused at least five times without the decrease of catalytic activity, showing excellent recyclability. The interactions between IL and the substrate methanol and the model compound ethyl acetate were investigated by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance techniques, and on the basis of these results, the plausible mechanisms of acidic and basic ILs catalyzed alcoholysis of EVA were proposed.

Corrosion inhibition of mild steel in 0.5 M HCL by substituted 1,3,4-oxadiazole

Organic inhibitors are normally used to inhibit the corrosion of metals or alloys in an aqueous environment. The anti-corrosive property of 5((6-Methyl-2-oxo-2H-chromen-4yl)thiomethyl)-2((N-(3-methyl-quinoxalin-2(1H)one)yl) methyl)-1,3,4-oxadiazole (MOD) on mild steel (MS) was studied. Which acts as a novel corrosion inhibitor for MS in 0.5 M Hydrochloric acid (HCl) solution and corrosion behavior in the temperature range of 303–323 K, without and with the MOD inhibitor, was calculated using potentiodynamic polarization, electrochemical impedance spectroscopy, and weight loss measurements. The surface topography of mild steel with, and without MOD was investigated by Scanning electron microscopy (SEM) technique. The inhibitory efficiency increases with an increase in MOD (50 ppm) concentration and showed a maximum of 84.85% in 0.5 M HCl at 303 K. The variation in kinetic and thermodynamic properties of MOD on MS indicates chemisorption and its mixed kind of inhibition activity followed by the Langmuir adsorption isotherm. The experimental results are supported by Density functional theory (DFT) simulations, indicating a potential corrosion inhibition behaviour of MOD on MS in acidic environments. A suitable mechanism for the corrosion inhibition of mild steel was put forth. The corrosion inhibition mechanism of mild steel was discussed. Mild steel is a low-cost engineering material that can be regularly used for various applications such as construction, advertising, vehicles, furniture, fencing, and more in various conditions, including mild acidic ones with a little caution.

Novel Phthalic-Based Anticancer Tyrosine Kinase Inhibitors: Design, Synthesis and Biological Activity.

In this work, fragments of isophthalic and terephthalic acids are proposed as a structural scaffold to develop potential inhibitors of protein kinases. Novel isophthalic and terephthalic acid derivatives were designed as type-2 protein kinase inhibitors, synthesized and subjected to physicochemical characterization. The screening of their cytotoxic actions against a panel of cell lines derived from different types of tumors (liver, renal, breast and lung carcinomas, as well as chronic myelogenous and promyelocytic leukemia) and normal human B lymphocyte, for the sake of comparison, was performed. Compound 5 showed the highest inhibitory activity against four cancer cell lines, K562, HL-60, MCF-7 and HepG2 (IC50 = 3.42, 7.04, 4.91 and 8.84 µM, respectively). Isophthalic derivative 9 revealed a high potency against EGFR and HER2, at the levels of 90% and 64%, respectively, being comparable to lapatinib at 10 µM. In general, tumor cell cultures were more sensitive to isophthalic acid derivatives than to terephthalic acid ones. In cell cycle studies, isophthalic analogue 5 showed a pronounced dose-dependent effect, and with the increase in its concentration up to 10.0 µM, the number of living cells decreased to 38.66%, while necrosis reached 16.38%. The considered isophthalic compounds had a similar docking performance to that of sorafenib against the VEGFR-2 (PDB id: 4asd, 3wze). The correct binding of compounds 11 and 14 with VEGFR-2 was validated using MD simulations and MM-GPSA calculations.