Viscosity Experiments Research Articles

Road Performance of Cold Repaired Asphalt Mixture with New Green Maintenance Materials

Cold patched asphalt mixture plays a crucial role in road maintenance, providing flexibility and the ability to quickly recover from harsh weather conditions. This article conducts in-depth research on the performance of cold patched asphalt mixture through multiple experiments, with special attention paid to the influence of diluent content and curing conditions on its performance. The experimental results show that using a mixture of green curing agents is feasible, and the diluent content is one of the main factors affecting the physical properties of cold patched asphalt. The optimal content of asphalt diluent was determined to be 25% through mass evaporation experiments and rotational viscosity experiments. Meanwhile, it was found that single component polyurethane prepolymers and SBS curing agents have a negative impact on the adhesion of cold patched asphalt, but have an improving effect on its strength, high-temperature resistance, and water stability. After comparing the performance of cold patched asphalt mixtures under different curing conditions, it was found that the performance of cold patched materials with long-term curing was better. Finally, this study determined the optimal dosage ratio of base asphalt, bio oil diluent, and single component polyurethane prepolymer as 100:25:12, providing technical support for the design and application of cold patched asphalt concrete pavement under high adverse weather conditions.

Effect of solution environment on the binding properties of ruthenium(II) complexes [Ru(bim)2(7-CH3-dppz)]2+ and [Ru(bim)2(dppx)]2+ with double-stranded RNA poly(A)·poly(U)

Two new ruthenium(Ⅱ) complexes containing the same ancillary ligands and different intercalating ligands, [Ru(bim)2(7-CH3-dppz)]2+ (Ru1, bim = 2,2′-biimidazole, 7-CH3-dppz = 7-methyl-dipyrido-[3,2-a,2′,3′-c]-phenazine) and [Ru(bim)2(dppx)]2+ (Ru2, dppx = 7,8-dimethyldipyridophenazine), have been synthesized and characterized in this work, and the interactions of Ru1 and Ru2 with double-stranded RNA poly(A)·poly(U) have been comparatively studied under both dilute and molecular crowding conditions. Analysis of spectral titrations and viscosity experiments as well as thermal denaturation experiments suggests that although complexes Ru1 and Ru2 in both dilute and molecular crowding solutions bind to poly(A)·poly(U) via intercalation, while the binding and stabilizing effects of the two complexes toward poly(A)·poly(U) under molecular crowding conditions significantly decreases in comparision with those in dilute solutions, suggesting that molecular crowding has a significant weakening effect on the interaction of the two complexes with poly(A)-poly(U). The results obtained will contribute to the understanding of the effects of molecular crowding conditions on the binding and stabilization of double-stranded RNA by metal complexes, in particular Ru(II) complexes.

Application of fume silica nanoparticles to improve high-temperature rheological performance of terminal blend rubberized asphalt

This study aims to evaluate the impact of fume silica nanoparticles (FSNPs) on the high-temperature rheological properties of terminal blend rubberized asphalt (TBRA). In this study, FSNPs were utilized to modify TBRA asphalt with three different CR contents (30%, 40%, 50%). The micro-morphology of FSNPs was observed through Scanning Electron Microscopy (SEM) experiments. The effects of FSNPs on the high-temperature rheological properties of TBRA were assessed using temperature sweep tests, Multiple Stress Creep Recovery (MSCR), and rotational viscosity tests. Furthermore, the influence of FSNPs on the chemical and thermal properties of TBRA was analyzed through Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) tests. Rheological tests and SEM results indicate that FSNPs can effectively enhance the high-temperature elasticity, fatigue resistance, and deformation resistance of TBRA binders. This improvement is attributed to the unique branched network structure of FSNPs, which plays a pivotal role in enhancing the elasticity within the TBRA asphalt matrix. Additionally, the degradation of TBRA's low-temperature performance due to FSNPs is minimal. Considering the optimal viscosity for FSPN-modified TBRA, recommended ratios are: TB30/6%, TB40/4%, and TB50/2%. FTIR and TGA results demonstrate that the modification of TBRA by FSNPs is primarily physical blending, and the addition of FSNPs enhances the thermal stability of TBRA.

Binding properties of ruthenium(II) polypyridyl complexes [Ru(bpy)2(L)]2+(L=7-F-dppz and 7OCH3–-dppz) with poly(A)-poly(U) under dilute and molecular crowding conditions

Two ruthenium(II) polypyridyl complexes, [Ru(bpy)2(7-F-dppz)]2+ (Ru1, bpy = 2,2′-bipyridine, 7-F-dppz = 7-fluorodipyrido[3,2-a:2′,3′-c]phenazine) and [Ru(bpy)2(7OCH3–-dppz)]2+ (Ru2, 7OCH3–-dppz = 7‑methoxy-dipyrido-[3,2-a,2′,3′-c]-phenazine), were synthesized. The binding properties of Ru1 and Ru2 to duplex RNA poly(A)-poly(U) have been explored through spectroscopic techniques and viscometry. Spectral titration and viscosity experiments show that the binding mode of Ru1 and Ru2 to double-stranded RNA(dsRNA) in dilute solution and molecular crowded environment are intercalation, and that the binding affinity of Ru1 for poly(A)-poly(U) is greater than that of Ru2. Thermal denaturation experiments showed that two complexes have good thermal stability for dsRNA in two environments. Fluorescence titrations showed that Ru1 and Ru2 could act as molecular "light switch" for duplex poly(A)-poly(U) in both environments. Surprisingly, the binding effect of ligands and poly(A)-poly(U) was significantly reduced under crowded condition, and the thermal stability of RNA duplex was less significant than that of dilute solution. The reason of this result is due to the water activity in molecular crowded environment, the increased viscosity of the medium leading to a decrease in the affinity of the ligand for the RNA duplex, and also the electronic effect of the ligand on the binding affinity of the poly(A)-poly(U). Results of the present work facilitate our understanding of the two environments as well as the interaction between ruthenium(II) polypyridyl complexes and dsRNA is influenced by the electronegativity of the substituents.

Studies on interactions of ruthenium(II) polypyridyl complexes [Ru(bpy)2(btip)]2+ and [Ru(dmb)2(btip)]2+ with double-stranded RNA poly(A)·poly(U) under molecular crowding conditions

Ruthenium(II) polypyridyl complexes have emerged as excellent nucleic acid binders based on the easy-to-construct three-dimensional structures and rich photophysical and photochemical properties. However, most studies are usually performed under dilute conditions, which might be disturbed by the crowding environment of cells. Herein, two ruthenium(II) polypyridyl complexes, [Ru(bpy)2(btip)]2+ (Ru1, bpy = 2,2′-bipyridine, btip = 2-benzo[b]thien-2-yl-1H-imidazo[4,5-f]-[1,10]phenanthroline) and [Ru(dmb)2(btip)]2+ (Ru2, dmb = 4,4′-dimethyl-2,2′-bipyridine) have been synthesized and characterized. Interactions of the two complexes with double-stranded RNA poly(A)·poly(U) in dilute solution and molecular crowding environment have been studied by spectroscopic techniques and viscosity measurements, respectively. Spectral titration and viscosity experiments show that both Ru1 and Ru2 combine with poly(A)·poly(U) through an intercalative mode in both environments, and the binding affinity in crowding environment is significantly lower than that in dilute solution, but still comparatively high. Moreover, thermal denaturation experiments show that the abilities of Ru1 and Ru2 to poly(A)·poly(U) are significantly reduced under crowding condition, which are attributed to the reduced binding affinity of the complexes to poly(A)·poly(U) in crowding environment.

Design of Janus Nanoparticles for Mobility Control in Heterogeneous Reservoirs.

Unfavorable mobility ratios in heterogeneous reservoirs have resulted in progressively poor waterflood sweep efficiency and diminishing production. In order to address this issue, our study has developed amphiphilic-structured nanoparticles aimed at enhancing the microscopic displacement capability and oil displacement efficiency. First, the transport process of Janus nanoparticles in porous media was investigated. During the water flooding, Janus nanoparticle injection, and subsequent water flooding stages, the injection pressure increased in a "stepped" pattern, reaching 0.023, 0.029, and 0.038 MPa, respectively. Second, emulsification effects and emulsion viscosity experiments demonstrated that the amphiphilic structure improved the interaction at the oil-water interface, reducing the seepage resistance of the oil phase through emulsification. In porous media, Janus nanoparticles transported with water exhibit 'self-seeking oil' behavior and interact with the oil phase, reducing the viscosity of the oil phase from 19 to 5 mPa·s at 80 °C. Finally, the core model displacement experiment verified the characteristics of Janus nanoparticles in improving the oil-water mobility ratio. Compared with the water flooding stage, the recovery percent increased by 20.8%, of which 13.7% was attributed to the subsequent water flooding stage. Utilizing the asymmetry of the Janus particle structure can provide an effective path to enhanced oil recovery in inhomogeneous reservoirs.

Viscosity of Mono‐ and Polydisperse Mixtures of Photopolymer and Rigid Spheres for Manufacturing of Engineered Composite Materials Using Vat Photopolymerization

Vat photopolymerization (VP) additive manufacturing involves selectively curing low‐viscosity photopolymers via exposure to ultraviolet light in a layer‐wise fashion. Dispersing filler materials in the photopolymer enables tailored end‐use properties, but also increases the viscosity and the timescale associated with interparticle network structural recovery postshear. These rheological properties influence self‐leveling and recoating of the liquid photopolymer mixture during VP. Herein, viscosity of photopolymer and rigid spherical glass microparticles (filler) is experimentally determined as a function of filler fraction, filler size distribution (mono‐ and polydisperse), shear rate, and temperature, which are important VP process parameters. Employing existing viscosity models for mono‐ and polydisperse polymer mixtures demonstrates that particle–particle interactions and the formation of nonspherical clusters of particles strongly affect the viscosity of both monodisperse and polydisperse mixtures with particle volume fractions > 0.05 due to agglomeration/deagglomeration of clusters at elevated shear rates. Consequently, unmodified viscosity models, which assume uniformly dispersed, rigid, spherical particles, are applicable only for mixtures with particle volume fractions < 0.05. It is shown that modifying model parameters such as the fluidity limit and intrinsic viscosity, which explicitly account for nonspherical clusters of particles, improves agreement between viscosity models and experiments, in particular when using a fractal approach.

β-Cyclodextrin modified SiO2 nanofluid for enhanced oil recovery

Recently, with the deterioration of oil storage conditions, the extraction of oil has been limited. In this experiment, β-cyclodextrin (β-CD) was grafted onto the surface of SiO2 nanoparticles. The structure and morphology of nanoparticles were analyzed by various characterization tools to effectively validate the synthesis of nanomaterials. In addition, it was experimentally demonstrated that the developed β-CD-SiO2 nanofluid has excellent stability and salt resistance. Finally, the comparative studies of the nanofluids were carried out by wettability, interfacial tension (IFT), Pickering emulsion, viscosity, and core flooding experiments. The results showed that β-CD-SiO2 nanofluid exhibited better performance: β-CD-SiO2 nanofluid changed the contact angle (CTA) of carbonate plate from 131.5º to 90.1º; the IFT was significantly reduced from about 35 mN/m to 22.5 mN/m; the emulsion droplets formed were fine and dense; the viscosity increased and viscosity not changed with shear rate; and total crude oil recovery up to 59.2%, 23.9% higher than using water drives. Overall, these results showed the great potential of β-CD-SiO2 nanofluid in ultra-low permeability reservoirs.

Effects of high hydrostatic pressure on the functional properties of soy protein isolate

AbstractIn this study, functional properties of high hydrostatic pressure (HHP)‐treated soy protein isolate (SPI) samples including protein solubility, emulsification activity (EA), and water holding capacity (WHC) were studied. Fourier transform infrared spectroscopy (FTIR), viscosity, and nuclear magnetic resonance (NMR) relaxometry experiments were performed. Three pressure (300, 400, and 500 MPa), two pH (5.0 and 7.0), and two temperature levels (25 and 40°C) were used to prepare SPI samples. Solubility of SPI was more pH‐dependent than HHP‐dependent, whereas WHC was more sensitive to pressure. Samples processed at 300 MPa, pH 5.0, and 40°C demonstrated higher EA (p < .05) than the untreated samples. Pressure application significantly reduced the viscosity of SPI dispersions (p < .05). Samples processed at 300 MPa, pH 5.0, and 40°C and at 400 MPa, pH 5.0, and 40°C attained the longest transverse relaxation time (T2) values reflecting their low solubility profiles. Thus, results indicated that HHP was able to modify the functional properties of SPI at different temperature and pH conditions.Practical ApplicationsHigh hydrostatic pressure (HHP) is an emerging technology with its diverse range of applications in food industry. Modification of functional properties of food ingredients is one of the latest applications of HHP treatment. This study demonstrated that HHP treatment was able to modify some functional properties of soy protein isolate (SPI) samples including water holding capacity, solubility, and emulsification activity. Pressure level, pH, and temperature affected the functional properties of SPI samples. The parameter type/range and results of this study could be used in model HHP studies to improve some functional properties of SPI for different purposes.

Dimension and Flexibility of Polystyrenesulfonate Chains in Methanol-Water.

The influence of the relative permittivity of the solvent medium on the single-chain dimension and flexibility of sodium polystyrenesulfonate chains has been investigated in mixed solvent media of methanol and water using viscosity experiments. Particular attention has been paid to explore the effect of the added low-molar-mass electrolyte. The root-mean-square (rms) radii of gyration of the chains in the unperturbed state have been calculated by applying the Flory model, while the intrinsic persistence lengths by the Benoit-Doty equation on the basis of the Kratky-Porod worm-like chain model. Estimation of the expansion factors for the rms radius of gyration, and the electrostatic persistence length helps evaluate the rms radii of gyration and the total persistence length of polystyrenesulfonate chains in the presence of varying amount of the supporting electrolyte. The polyion chains are highly extended at low ionic strengths but exhibit coil-like behavior with small persistence lengths when an excess of the supporting electrolyte is added in all the methanol-water mixtures investigated. Specifically, in the investigated solvent media, the polystyrenesulfonate chains have been found to shrink by ∼63-65% in the θ-state from their expanded conformation in the presence of 0.0001 mol L-1 NaCl. The chain dimensions pass through a maximum as the medium becomes richer in methanol, which could be explained by the formation and breakup of internal rings involving the polyion chain and water and/or methanol molecules. The intrinsic persistence length of sodium polystyrenesulfonate in a methanol-water mixture containing 0.1 mole fraction of methanol is ca. 1.3 times that in a medium with 0.3 mole fraction of methanol, indicating that flexibility of the polyion depends appreciably on the relative permittivity of the medium.

Search for new biologically active compounds: in vitro studies of antitumor and antimicrobial activity of dirhodium(II,II) paddlewheel complexes.

Four neutral Rh1-Rh4 complexes of the general formula [Rh2(CH3COO)4L2], where L is an N-alkylimidazole ligand, were synthesized and characterized using various spectroscopic techniques, and in the case of Rh4 the crystal structure was confirmed. Investigation of the interactions of these complexes with HSA by fluorescence spectroscopy revealed that the binding constants Kb are moderately strong (∼104 M-1), and site-marker competition experiments showed that the complexes bind to Heme site III (subdomain IB). Competitive binding studies for CT DNA using EB and HOE showed that the complexes bind to the minor groove, which was also confirmed by viscosity experiments. Molecular docking confirmed the experimental data for HSA and CT DNA. Antimicrobial tests showed that the Rh2-Rh4 complexes exerted a strong inhibitory effect on G+ bacteria B. cereus and G- bacteria V. parahaemolyticus as well as on the yeast C. tropicalis, which showed a higher sensitivity compared to fluconazole. The cytotoxic activity of Rh1-Rh4 complexes tested on three cancer cell lines (HeLa, HCT116 and MDA-MB-231) and on healthy MRC-5 cells showed that all investigated complexes elicited more efficient cytotoxicity on all tested tumor cells than on control cells. Investigation of the mechanism of action revealed that the Rh1-Rh4 complexes inhibit cell proliferation via different mechanisms of action, namely apoptosis (increase in expression of the pro-apoptotic Bax protein and caspase-3 protein in HeLa and HCT116 cells; changes in mitochondrial potential and mitochondrial damage; release of cytochrome c from the mitochondria; cell cycle arrest in G2/M phase in both HeLa and HCT116 cells together with a decrease in the expression of cyclin A and cyclin B) and autophagy (reduction in the expression of the protein p62 in HeLa and HCT116 cells).

Viscosity experiments of slag-spinel suspensions: The effect of volume fraction, particle size, and shear rate

Heterogeneous slag viscosity measurements have a wide variety of parameters, such as particle size, shape, solid volume fraction, and shear rate, which affect the final measured viscosity. Often, some of these parameters are neglected or predicted via models, since it is experimentally difficult to determine them during high-temperature slag viscosity measurements. In this work, a viscosity apparatus was used, which allows quenching of the sample after measurement. This way, all relevant parameters could be experimentally determined. The viscosities of three datasets were studied with various spinel sizes: small (13 μm), medium (34 μm), and large particles (76 μm). Within each dataset, the composition of the liquid slag matrix was kept constant to uniquely measure the effect of solids. Shear thinning, i.e., a decreasing viscosity with increasing shear rate, was observed for all samples, even at a low vol. % of 1.8. Moreover, stronger shear thinning was observed at a higher vol. % and for smaller spinel particles. On the basis of these results, the phenomenon of shear thinning was discussed and mainly attributed to the particle–particle orientation in the suspension. The obtained viscosity values were used to optimize a Krieger–Dougherty equation, which describes the viscosity increase caused by the presence of a certain vol. % of spinel particles, with a certain size and at a specific shear rate.

Interpolation and extrapolation in Year 5 STEM activities: exploring data about viscosity without advanced statistics

AbstractIncorporating an evidence-based approach in STEM education using data collection and analysis strategies when learning about science concepts enhances primary students’ discipline knowledge and cognitive development. This paper reports on learning activities that use the nature of viscosity and the power of informal statistical inference to build students’ conceptual understanding of interpolation and extrapolation without imposing on them the demands of understanding the nonlinear mathematics used to explore the concepts at the tertiary level. An exploratory research strategy was adopted to investigate the way in which Year 5 students created and analysed graphical representations from data collected when performing viscosity experiments. The data representations produced by the students and their subsequent predictions were analysed using the Structure of Observed Learning Outcomes (SOLO) model as adapted specifically for graphical representations. The results illustrate that when provided with appropriate technological tools to scaffold student learning, in this case TinkerPlots™, development of students’ appreciation of interpolation and extrapolation within meaningful data contexts across the STEM curriculum does not have to wait until the tertiary level.

Comprehensive investigation of Co(II), Ni(II) and Cu(II) complexes derived from a novel Schiff base: Synthesis, characterization, DNA interactions, ADME profiling, molecular docking, and in-vitro biological evaluation

Here, anisidine-based ligand (HL) and its cobalt (1a), nickel (1b) and copper (1c) complexes were synthesized and characterized by various spectroscopic techniques such as NMR, mass, IR, UV–visible, magnetic moments, ESR and TGA. The synthesized [Ni(L)2] and [Cu(L)2] complexes demonstrated square planar geometry around the metal centers, while the cobalt complex [Co(L)2(H2O)2] adopted six coordinated octahedral geometries. The DNA interaction studies of the complexes revealed an intercalative mode of binding, as evidenced by UV absorption, emission, and viscosity experiments, and the binding constant (Kb) follows the order of 1c > 1a > 1b. When exposed to oxidative and photolytic methods, the complexes demonstrated better efficacy in cleaving double-stranded pBR322 DNA compared to their parent Schiff base. When tested for cytotoxicity against A549 and MCF7 cell lines, complexes showed more activity than their parent ligand. In-vitro studies of the complexes' antimicrobial and antioxidant properties shown that they are far more effective than the parent ligand. Further, the biological efficiency of the ligand (HL) and complexes were verified by computational methods, including molecular docking (against protein data bank PDB ID: 2ADO.pdb) and pharmacokinetic studies, both the ligand (HL) and complexes have demonstrated significant potency. This promising result indicated their potential as therapeutic agents for treating pathogen-induced deformities.

Five new diorganotin complexes containing arylformylhydrazone ligands as anticancer agents

Five diorganotin complexes were synthesized through the reactions involving benzoyl hydrazine, sodium phenylpyruvate, and the respective dialkyltin compounds. All complexes underwent comprehensive characterization employing various techniques, including infrared spectroscopy, nuclear magnetic resonance spectroscopy (1H, 13C, 119Sn), high-resolution mass spectrometry, elemental analysis, X-ray single crystal diffraction, and thermogravimetric analysis. The structural analysis revealed that the ligands in the complexes adopted a tridentate chelating mode. In order to assess their potential as antitumor agents, the complexes were subjected to an in vitro evaluation using the Cell Counting Kit-8 assay. The results indicated that C2 exhibited enhanced efficacy, suggesting its suitability for further chemical optimization and potential application in cancer therapy. Molecular docking was employed to predict the binding mode between complex and DNA. To gain insights into the interaction between C2 and DNA a series of experiments, including viscosity experiments, ultraviolet-visible spectrophotometry, fluorescence spectroscopy, and gel electrophoresis were conducted. The findings consistently demonstrated that C2 interacted with DNA via intercalation.

DNA major versus minor groove occupancy of monomeric and dimeric crystal violet derivatives. Toward structural correlations

Six monomeric (1a-1f) and five dimeric (2a-2e) derivatives of the triphenylmethane dye crystal violet (CV) have been prepared. Evaluation of the binding of these compounds to CT DNA by competitive fluorescent intercalator displacement (FID) assays, viscosity experiments, and UV and CD spectroscopy suggest that monomeric derivative 1a and dimeric derivative 2d likely associate with the major groove of DNA, while dimeric derivatives 2a and 2e likely associate with the minor groove of DNA. Additional evidence for the groove occupancy assignments of these derivatives was obtained from ITC experiments and from differential inhibition of DNA cleavage by the major groove binding restriction enzyme BamHI, as revealed by agarose gel electrophoresis. The data indicate that major groove ligands may be optimally constructed from dye units containing a sterically bulky 3,5-dimethyl-N,N-dimethylaniline group; furthermore, the groove-selectivity of olefin-tethered dimer 2d suggests that stereoelectronic interactions (n → π*) between the ligand and DNA are also an important design consideration in the crafting of major-groove binding ligands.

Explication of polydopamine modified g-C3N4 as effective additive in PVDF nanocomposite membrane fabrication for enhanced ultrafiltration and self-cleaning performance

Nanocomposite membranes (NCMs) incorporated with nanomaterials have recently received increasing attention, but the preparation of high-performance membranes is still challenging due to the hydrophilicity and self-aggregation of the nanoparticles. In this study, graphite carbon nitride containing nitrogen defects was modified using dopamine (PDA@DCN) for effective alleviation of the agglomeration of nanoparticles resulting in a uniform casting solution. A non-solvent-induced phase separation method was adapted to prepare PVDF NCMs by using PDA@DCN as an effective additive. Superior permeability and selectivity were exhibited by the PDA0.25 @DCN/PVDF2 membrane (where a DA concentration of 0.25 g/100 mL was used in PDA@DCN preparation and 2% PVP was added during the membrane preparation) with the pure water flux of 390 L/(m2·h) and Bovine serum albumin (BSA) rejection of 95.9%. The extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory revealed that the improvement of the flux recovery rate of PDA0.25 @DCN/PVDF2 was due to the decreased attractive interaction for fouling. Ternary phase diagram and viscosity experiments confirmed that the addition of PDA0.25 @DCN accelerated phase inversion rate (as evident from thermodynamics and kinetics) and increased the porosity with smaller average surface pore size, which is expected to have good permeability and selectivity as an ultrafiltration membrane. Moreover, an excellent self-cleaning performance was demonstrated by PDA0.25 @DCN/PVDF2, with a flux recovery rate of 84.5%, simply under visible light irradiation, which indicates its potential for environment-friendly practical application.

Biophysical study on DNA and BSA binding activity of Cu(II) complex: Synthesis, molecular docking, cytotoxic activity, and theoretical approach

The bidentate (N, O) donor Schiff base, methyl‐4‐(2‐hydroxybenzylidene‐amino) benzoate (HL), was synthesized for the synthesis of CuL2 complex. Their structures were characterized by single crystal X‐ray diffraction and spectroscopic methods. The important structural features of ligand HL are (space group: Pca21; a = 6.1434(7) Å; b = 7.1021(7) Å; c = 28.963(3) Å; α = 90.00°; β = 90.00°, and γ = 90.00°) and of CuL2 are (space group: P21/n; a = 15.763(7) Å; b = 8.1921(5) Å, and c = 20.1955(8) Å; α = 90.00°; β = 96.547(4)°, and γ = 90.00°). The DFT/TD‐DFT studies were performed to evaluate the structure optimization, MEP plot, and electronic spectroscopy data as well as the HOMO‐LUMO energy and also other electronic descriptor properties. The DNA and BSA binding property of both the ligand and complex were studied employing a variety of spectroscopic methods, viscosity experiments, and gel electrophoresis technique. Their biophysical study including 3D fluorescence, FRET calculation, and anisotropy measurements with BSA were studied by spectrofluorometric methods. The molecular docking simulation of the ligand HL and CuL2 was executed with DNA and BSA to observe their different weak and strong binding interactions and to compare their binding aptitude with biomolecules and experimental results. The software “PASS” for drug likeness prediction and “ADMET” for bioactivity were implemented to get an idea about the antineoplastic and bioactivity aspects of HL and CuL2 complex. The anticancer property of the Cu(II) complex was measured by MTT assay against human breast carcinomas (MCF‐7) cancer cell line and as well as normal human embryonic kidney cells (HEK293) and is less toxic and comparable anticancer activity compared to cisplatin and oxaliplatin. The annexin V‐FITC, propidium iodide assay by flow cytometric method, and reactive oxygen species (ROS) production assay by DCFDA were assessed in presence of the HL and CuL2 for their cell death mechanism proceed via either apoptosis or necrosis.

Synthesis, Characterization, DNA/HSA Interaction, and Cytotoxic Activity of a Copper(II) Thiolate Schiff Base Complex and Its Corresponding Water-Soluble Stable Sulfinato-O Complex Containing Imidazole as a Co-ligand.

A Cu(II) thiolato complex [CuL(imz)] (1) (H2L = o-HOC6H4C(H)=NC6H4SH-o) and the corresponding water-soluble stable sulfinato-O complex [CuL'(imz)] (2) (H2L' = o-HOC6H4C(H)=NC6H4S(=O)OH) were synthesized and characterized using physicochemical techniques. Compound 2 is found to be a dimer in the solid state as characterized using single-crystal X-ray crystallography. XPS studies clearly showed the differences in the sulfur oxidation states in 1 and 2. Both compounds are found to be monomers in solution as revealed from their four-line X-band electron paramagnetic resonance spectra in CH3CN at room temperature (RT). 1-2 were tested to assess their ability to exhibit DNA binding and cleavage activity. Spectroscopic studies and viscosity experiments suggest that 1-2 bind to CT-DNA through the intercalation mode having moderate binding affinity (Kb ∼ 104 M-1). This is further supported by molecular docking studies of complex 2 with CT-DNA. Both complexes display significant oxidative cleavage of pUC19 DNA. Complex 2 also showed hydrolytic DNA cleavage. The interaction of 1-2 with HSA revealed that they have strong ability to quench the intrinsic fluorescence of HSA by a static quenching mechanism (kq ∼ 1013 M-1 s-1). This is further complemented by Förster resonance energy transfer studies that revealed binding distances of r = 2.85 and 2.75 nm for 1 and 2, respectively, indicating high potential for energy transfer from HSA to complex. 1-2 were capable of inducing conformational changes of HSA at secondary and tertiary levels as observed from synchronous and three-dimensional fluorescence spectroscopy. Molecular docking studies with 2 indicate that it forms strong hydrogen bonds with Gln221 and Arg222 located near the entrance of site-I of HSA. 1-2 showed potential toxicity in human cervical cancer HeLa cells, lung cancer A549 cells, and cisplatin-resistant breast cancer MDA-MB-231 cells and appeared to be most potent against HeLa cells (IC50 = 2.04 μM for 1 and 1.86 μM for 2). In HeLa cells, 1-2 mediated cell cycle arrest in S and G2/M phases, which progressed into apoptosis. Apoptotic features seen from Hoechst and AO/PI staining, damaged cytoskeleton actin viewed from phalloidin staining, and increased caspase-3 activity upon treatment with 1-2 collectively suggested that they induced apoptosis in HeLa cells via caspase activation. This is further supported by western blot analysis of the protein sample extracted from HeLa cells treated with 2.

Preparation and curing behaviour of microencapsulated curing agents for cold-mixed epoxy asphalt

This study aimed to improve control over the curing behaviour of cold-mixed epoxy asphalt by using a microencapsulated curing agent (2-PZ@PC). Prepared through solvent evaporation, the 2-PZ@PC microcapsules had 2-phenylimidazole as the core material and polycarbonate as the shell material. The research examined the impact of core–shell mass ratio on microcapsule morphology and composition. Various equations, including the kinetics equation, Kissinger equation, Flynn–Wall–Ozawa, and Crane equations, were employed to assess the sustained release effect of 2-PZ@PC microcapsules on epoxy resin curing behaviour. Fluorescence microscopy and viscosity experiments were used to observe the release state of microcapsules and confirm the retardation phenomenon during construction. Optimal 2-PZ@PC microcapsules displayed a smooth spherical morphology and a maximum encapsulation rate of 32 wt% at a 1:1 core–shell ratio. The microencapsulated curing agent effectively regulated cold-mixed epoxy asphalt’s curing behaviour, enhancing retention time control and application reliability.