Ion Activity Research Articles

Preparation and mechanical properties of biomimetic mineralization collagen for dopamine-polyacrylamide-induced small intestinal submucosa

Bone-like lamellar hydroxyapatite(HAP) was successfully synthesized by biomimetic mineralization on small intestinal submucosa(SIS) induced by dopamine(DA)-polyacrylamide (PAM).HAP was uniformly grown by the method of “collagen fiber active site-regulated ion nucleation growth” on SIS film by a lab-built ion diffusion experimental system. The hydrophilic angles before and after SIS modification were 85.3 ± 1.3° and 35.7 ± 1.2°, respectively. The morphology of grow HAP crystals was similar to that of nature bone. Then, DA-PAM@SIS/HAP material was prepared to mimic bone components and basic unit microstructure of natural bones. The tensile strength of composites was about 12 MPa, which was 2.4 times higher than that of the unmineralized films. The mineralized film should be expectedto be applied in the field of bone remodeling and bone tissue engineering.

Photo‐Induced Active Ion Transport‐Assisted Efficient Ionic Power Harvesting from Bioinspired Janus Dual‐Field Heterostructures

AbstractNatural organisms have developed various biological ion channels/transporters to maintain normal life activities to adapt to changing environments. Significantly, ion transporters with active ion transport property show much more controllability on these activities due to a variety of external stimuli, giving guidance to construct artificial counterparts for overcoming the issues in simple nanofluidic systems restricted by self‐diffusive ion transport. Herein, a 2D nanofluidic system based on a Janus membrane (i.e., JM) is constructed, which can achieve light‐driven active ion transport and do favor for ionic power harvesting in electrolyte systems with equal concentrations. The JM is obtained through sequentially assembled montmorillonite (MMT) decorated with photoelectric molecules (i.e., PMMT) and MXene nanosheets. Due to the formed intramembrane electric field and temperature gradient caused by the efficient charge separation and localized thermal excitation under light illumination, a photovoltaic‐driven force and thermo‐osmotic are generated for preferential ion transport. In addition, the unidirectional active transport is employed to harvest ionic power, showing an output power density of 2.0 mW m−2 and a high‐performance energy conversion efficiency of 8.3 × 10−4%. The effects of the light intensity, electrolyte concentration and species on energy conversion performance are investigated, showing the university for ionic power harvesting.

Electrochemical activity of 3d transition metal ions in polyanionic compounds for sodium‐ion batteries

AbstractSodium‐ion batteries are expected to replace lithium‐ion batteries in large‐scale energy storage systems due to their low cost, wide availability, and high abundance. Polyanionic materials are considered to be the most promising cathode materials for sodium‐ion batteries because of their cycling stability and structural stability. However, limited by its poor electronic conductivity, the electrochemical performance needs to be further improved. This paper reviews the characterization and development of 3d transition metal ions polyanionic compounds, along with the summarized effect of structure and particle size on the performance and improvement of electrochemical properties. Meanwhile, crystal structure modulation, transition metal ion choice, and transition metal ion doping can improve the electrochemical performance and energy density of polyanionic compounds. Finally, this review points out the challenges of polyanionic compounds and puts forward some particular standpoints, contributing to the promising development of polyanionic compounds in the large‐scale energy storage market.

The effect of Cu(II) ion on antioxidant and DNA‐binding mechanism of baicalein and scutellarein: Spectroscopic, theoretical, and molecular docking study

Flavonoids are a group of polyphenolic compounds known to possess good radical scavenging activity. It was also shown that their anti/prooxidant properties are strongly structure‐dependent and can be modified by metal ion binding. The structural parameters also appear to be key factors during their DNA‐binding abilities. This work deals with spectroscopic and theoretical studies of two flavonoids, baicalein and scutellarein, alone, and in the presence of redox‐active metal ion Cu(II). Cu(II) is the catalytic active ion in Fenton‐like reactions and can enhance the production of reactive oxygen species or, when bound to the flavonoid, influence its antioxidant potential. UV–Vis spectroscopy showed that the electronic properties of the parent flavonoids are changed following the CuCl2 addition. Job's plot method revealed the 1:1 binding mode of interaction in DMSO and DMSO/PBS solvent. The ABTS•+ assay showed only a negligible effect of Cu(II) presence on the antioxidant properties of baicalein and scutellarein. The mix of the natural reductant, glutathione, with flavonoids showed a synergistic effect in ABTS•+ inhibition; however, this effect was suppressed by the presence of Cu(II). Absorption titration and molecular docking studies showed an effective DNA binding of both flavonoids that is further enhanced by the presence of Cu(II). DFT calculations were carried out to identify the most energetically stable Cu(II)–flavonoid structures as well as to determine the ability of their hydroxyl groups to undergo homolytic or heterolytic cleavage.

Cactus-like NC/CoxP electrode enables efficient and stable hydrogen evolution for saline water splitting

Designing efficient and robust catalysts for hydrogen evolution reaction (HER) is imperative for saline water electrolysis technology. A catalyst composed of CoxP nanowires array with N-doped carbon nanosheets (NC) was fabricated on Ni foam (NF) by an in-situ growth strategy. The material is designated as NC/CoxP@NF. In the preparation process, Co(OH)2 nanowires were transformed into a metal organic framework of cobalt (ZIF-67) on NF by the dissolution-coordination of endogenous Co2+ and 2-methylimidazole. The resulting cactus-like microstructure gives NC/CoxP@NF abundant exposed active sites and ion transport channels, which improve the HER catalytic reaction kinetics. Furthermore, the interconnected alternating nanowires and free-standing nanosheets in NC/CoxP@NF improve its structural stability, and the formation of surface polyanions (phosphate) and a NC nanosheet protective layer improve the anti-corrosive properties of catalysts. Thus, the NC/CoxP@NF has an excellent performance, requiring overpotentials of 107 and 133 mV for HER to achieve 10 mA cm−2 in 1.0 mol L−1 KOH and 1.0 mol L−1 KOH + 0.5 mol L−1 NaCl, respectively. This in-situ transformation strategy is a new way of constructing highly-efficient HER catalysts for saline water electrolysis.

The pH estimation of decoction of hingu (Ferula foetida Regel,), chitraka (Plumbago zeylanica Linn), dhataki (Woodfordia fruticosa kurz), shatavari (Asperagus racemosus willd), shunthi (Zingiber officinale Rosc), maricha (Piper nigrum Linn), gokshura (Tri

The pH is measured on a scale of 0-14 with lower values indicating high H+ which is more acidic and higher values indicating H+ ion activity which is less acidic. The pH of 7 is considered as neutral. The acids are the substances that produce free hydrogen ions(H+) when dissolved in water. Bases are substances that produce hydroxyl ions(OH-) when dissolved in water. Acidic solutions are rich in hydrogen ions and basic solutions are poor in hydrogen ions. Some acids dissociate only partly, releasing large amounts of H+ ions, and are called as strong acids. In same way, bases that dissociate partly are called weak bases and those that dissociate completely are called as bases. The acidic or basic property of substances is measured in terms of pH. It is a measurement of the hydrogen ion concentration. pH is defined as the negative logarithm(Base 10) of hydrogen ion concentration. pH= - log[H+] If the hydrogen ion concentration id very high, the pH value is very low. This is determined using a scale ranging from 0-14 called the pH scale. It was introduced by a Danish chemist Soren Peder Lauritz Sorensen. Substances with pH lower than 7 are acidic, those with pH equal to 7 are neutral and those with pH greater than 7 are basic in nature. The pH of water is 7. In the present work the decoction of Hingu(Ferula foetida Regel,), Chitraka(Plumbago zeylanica Linn), Dhataki(Woodfordia fruticosa kurz), Shatavari(Asperagus racemosus willd), Shunthi(Zingiber officinale Rosc), Maricha(Piper nigrum Linn), Gokshura(Tribulus terrestris Linn) and Chandana(Santalum album Linn) were subjected for experimentation. The observed values were tabulated. The pH estimation helps to determine the acidic and basic strength of acids and bases.

Bioremediation of cadmium contaminated soil by tea waste and impact on the accumulation of Cd in Helianthus annuus

Abstract The work aimed to assess the restoration of metal-contaminated soil pH and EC and impacts on Cd accumulation in plants Helianthus annuus (Sunflower) through tea waste in a natural environment. Various doses of Cd metal treatment (1–5 ppm) were provided to the soil with two sets of organic matter (tea waste) in a dry and wet state. The soil and plants were analyzed using analytical procedures like AAS, SEM and EDS, while pH and EC were measured through pH and conductivity meter. The mitigating effect of tea waste was observed on the pH (6.2–6.9) and EC of the soil, which was reflected by the healthy growth of the plants. It was established that the movement of the Cd was successfully controlled with the restoration of essential nutrient elements in different parts of plants. It was strongly related to recovered soil pH and EC in two sets of tested H. annuus plant species. The healthy growth of the plants showed that tea waste acts as a safe, harmless and sound remediator of soil, which enhances the soil nutrient ionic activity from soil to roots of the plants in the presence of the Cd metal, effective for the use of agriculture purposes.

Efficient near‐infrared emission in lanthanum ion doped double perovskite Cs2NaScCl6 via Cr3+ sensitization under visible light excitation

AbstractHerein, we synthesized Cr3+/Ln3+ (Er3+, Tm3+)‐codoped rare earth‐based Cs2NaScCl6 double perovskite, and the near‐infrared emission of Ln3+ can be excited by visible light through the energy transfer (ET) from Cr3+ to Ln3+. Moreover, there are two independent emission bands, which stems from 4T2 → 4A2 transition of Cr3+ (970 nm) and f‐f transition of Ln3+ (1542 nm for Er3+ and 1220 nm for Tm3+), respectively. Particularly, both compounds have ultra‐high photoluminescence quantum yield (PLQY) of 60% for 10%Cr3+/6%Er3+‐codoped Cs2NaScCl6 (Er3+ emission: ∼26%) and 68% for 10%Cr3+/4.5%Tm3+‐codoped Cs2NaScCl6 (Tm3+ emission: ∼56%), which can be attributed to the ultra‐high ET efficiency from Cr3+ to Ln3+ and the similar ionic activity of Sc3+ and Ln3+ allowing more dopants enter the host lattice. Considering the excellent stability of the samples, we demonstrated Cr3+/Tm3+‐codoped Cs2NaScCl6 in the applications of near‐infrared imaging and night vision. Finally, we reported 10%Cr3+/4.5%Tm3+/9%Er3+‐tridoped Cs2NaScCl6 and further applied it for optical thermometry.image

Chemical Framework to Design Linear-like Relaxors toward Capacitive Energy Storage.

ABO3-type perovskite relaxor ferroelectrics (RFEs) have emerged as the preferred option for dielectric capacitive energy storage. However, the compositional design of RFEs with high energy density and efficiency poses significant challenges owing to the vast compositional space and the absence of general rules. Here, we present an atomic-level chemical framework that captures inherent characteristics in terms of radius and ferroelectric activity of ions. By categorizing A/B-site ions as host framework, rattling, ferroelectrically active, and blocking ions and assembling these four types of ions with specific criteria, linear-like relaxors with weak locally correlated and highly extendable unit-cell polarization vectors can be constructed. As example, we demonstrate two new compositions of Bi0.5K0.5TiO3-based and BaTiO3-based relaxors, showing extremely high recoverable energy densities of 17.3 and 12.1 J cm-3, respectively, both with a high efficiency of about 90%. Further, the role of different types of ions in forming heterogeneous polar structures is identified through element-specific local structure analysis using neutron total scattering combined with reverse Monte Carlo modeling. Our work not only opens up new avenues toward rational compositional design of high energy storage performance lead-free RFEs but also sheds light on atomic-level manipulation of functional properties in compositionally complex ferroelectrics.

Advanced thermodynamic approach to adsorption of charged adsorbates from aqueous electrolyte solutions

This study present estimation of the thermodynamic parameters and the influence of ionic activity coefficient on the thermodynamic equilibrium constant of adsorption of phosphates on fly ash. The adsorption was conducted over a wide range of initial phosphate concentrations at different pH values pH = (3; 7; 10). The adsorption results were treated using the Langmuir, Freundlich and Sips adsorption isotherms, which provide information about the maximum adsorption capacity. The Langmuir and Sips isotherms were a satisfactory fit to the adsorption data, especially at pH = 3, with an acceptable regression coefficient over the entire concentration range, Langmuir (r2 = 0.9737) and Sips (r2 = 0.9969). The estimated maximum phosphate sorption capacity of fly ash was 6.21 ± 0.68 (mmol·g−1) according to Langmuir and 4.19 ± 0.16 (mmol·g−1) according to the Sips model, at pH = 3.0. However, there is no data in the published literature for estimating the thermodynamic parameters of the phosphate adsorption process using thermodynamic models for activity coefficients. Novel approach of this paper was determination of the thermodynamic equilibrium constant and Gibbs free energy, using the Pitzer ion-interaction model to predict the nature of adsorption. The Pitzer-ion interaction model was used for the mixed ionic systems, taking into consideration the effect of other present ions besides phosphates in the equilibrium solution resulting from fly ash desorption. The procedure for comprehensive estimation of the ion activity coefficient at maximum adsorption capacity and the dimensionless thermodynamic equilibrium constant using Langmuir's and Sips’s constants was presented. The calculated value of the phosphate activity coefficient in the equilibrium solution was γH2PO4,e = 0.7003 ± 0.0027 and the converted molar activity coefficient was γH2PO4,e = 0.6903 ± 0.0027. The estimated values of Gibbs free energy were: ΔGL = −6.788 ± 0.521 kJ·mol−1 based on Langmuir equilibrium constant and ΔGa = −7.707 ± 0.527 kJ·mol−1 based on activity and thermodynamic equilibrium constant. According to Sips model, the adsorption process is even more spontaneous, with the Gibbs free energy calculated using the phosphate activity coefficient and the thermodynamic equilibrium constant, ΔGa = −9.707 ± 0.617 kJ·mol−1. Consideration of the ionic activity coefficient is particularly important for large, charged adsorbates at higher concentrations, as the absolute difference in free energy for adsorption is app. 12 %. The scientific contribution is reflected in obtaining the necessary and more accurate information for the improvement of adsorption processes and possibly for the upgrading of fly ash in overall wastewater treatment technology.

Drosophila ClC-c Is a Homolog of Human CLC-5 and a New Model for Dent Disease Type 1.

Drosophila serve as exceptional alternative models for in vivo and ex vivo research and may provide an avenue for in-depth investigation for human ClC-5 and Dent disease type 1 (DD1). The Drosophila ClC-c (CG5284) has sequence homology with human ClC-5 and is hypothesized to encompass similar functional and phenotypical roles with ClC-5 and variants that cause DD1. Ion transport function and activity of Drosophila ClC-c and homologous DD1 variants were assessed by voltage clamp electrophysiology. Membrane localization was demonstrated in Drosophila expressing a GFP-labeled construct of ClC-c. Genetic expression of an RNAi against ClC-c mRNA was used to generate a knock-down fly that serves as a DD1 disease model. Tubule secretion of cations and protein were assessed as well as the crystal formation in the Malpighian tubules. Voltage clamp experiments demonstrate that ClC-c is voltage-gated with Cl--dependent and pH-sensitive currents. Inclusion of homologous DD1 mutations pathogenic variants (S393L, R494W, and Q777X) impairs ClC-c ion transport activity. In vivo expression of ClC-c-eGFP in Malpighian tubules reveals that the membrane transporter localizes to the apical membrane and nearby cytosolic regions. RNAi knock-down of ClC-c (48% decreased mRNA expression) causes increased secretion of both urinary protein and Ca2+ as well as increased occurrence of spontaneous tubule crystals. Drosophila ClC-c shows orthologous function and localization to human ClC-5. Thus, Drosophila and ClC-c regulation may be useful for future investigations of Cl- transport, Ca2+ homeostasis and urinary protein loss in DD1.

Unveiling the Borohydride Ion through Force-Field Development.

The borohydride ion, BH4-, is an essential reducing agent in many technological processes, yet its full understanding has been elusive, because of at least two significant challenges. One challenge arises from its marginal stability in aqueous solutions outside of basic pH conditions, which considerably limits the experimental thermodynamic data. The other challenge comes from its unique and atypical hydration shell, stemming from the negative excess charge on its hydrogen atoms, which complicates the accurate modeling in classical atomistic simulations. In this study, we combine experimental and computer simulation techniques to devise a classical force field for NaBH4 and deepen our understanding of its characteristics. We report the first measurement of the ion's activity coefficient and extrapolate it to neutral pH conditions. Given the difficulties in directly measuring its solvation free energies, owing to its instability, we resort to quantum chemistry calculations. This combined strategy allows us to derive a set of nonpolarizable force-field parameters for the borohydride ion for classical molecular dynamics simulations. The derived force field simultaneously captures the solvation free energy, the hydration structure, as well as the activity coefficient of NaBH4 salt across a broad concentration range. The obtained insights into the hydration shell of the BH4- ion are crucial for accurately modeling and understanding its interactions with other molecules, ions, materials, and interfaces.

Formulating Local Environment of Oxygen Mitigates Voltage Hysteresis in Li-Rich Materials.

Li-rich cathode materials have emerged as one of the most prospective options for Li-ion batteries owing to their remarkable energy density (>900Wh kg-1). However, voltage hysteresis during charge and discharge process lowers the energy conversion efficiency, which hinders their application in practical devices. Herein, the fundamental reason for voltage hysteresis through investigating the O redox behavior under different (de)lithiation states is unveiled and it is successfully addressed by formulating the local environment of O2-. In Li-rich Mn-based materials, it is confirmed that there exists reaction activity of oxygen ions at low discharge voltage (<3.6V) in the presence of TM-TM-Li ordered arrangement, generating massive amount of voltage hysteresis and resulting in a decreased energy efficiency (80.95%). Moreover, in the case where Li 2b sites are numerously occupied by TM ions, the local environment of O2- evolves, the reactivity of oxygen ions at low voltage is significantly inhibited, thus giving rise to the large energy conversion efficiency (89.07%). This study reveals the structure-activity relationship between the local environment around O2- and voltage hysteresis, which provides guidance in designing next-generation high-performance cathode materials.

In Situ Spectroscopic Elucidation of the Electrochemical Potential Drop at Polyelectrolytes/Au Interfaces.

Polyelectrolytes have been widely applied in electrochemical devices. Understanding the polyelectrolyte/electrode interfaces is pivotal for polyelectrolyte-based applications. Here, we measured the electrochemical potential drop and the local activity of the mobile ion of H+ or OH- at the polyelectrolytes/Au interfaces by in situ electrochemical surface-enhanced Raman spectroscopy and voltammetry in three-electrode cells. We found that the potential dependences of the electrochemical potential drop in polyelectrolytes were smaller than that in conventional electrolyte solutions. The interfacial activity of H+ or OH- was much lower than that of bulk polyelectrolytes. The potential-dependent molecular dynamics simulations showed that the mobility of ionomers of polyelectrolytes in an electrostatic field was limited by a polymer matrix. These results suggested a characteristically thicker compact layer in the electrical double layer of a polyelectrolyte/electrode interface due to the accumulation of mobile H+ or OH- with a thicker hydration layer and immobile ionomers.

Efficient tunable visible and near-infrared emission in Sb3+/Sm3+-codoped Cs2NaLuCl6 for near-infrared light-emitting diode, triple-mode fluorescence anti-counterfeiting and information encryption

Rare earth ions (RE3+)-doped double perovskites have attracted tremendous attention for its fascinating optical properties. Nevertheless, RE3+ generally exhibits poor photoluminescence quantum yield (PLQY) for their parity-forbidden 4f-4f transition and the low doping concentration. Herein, we reported Sb3+/Sm3+-codoped rare earth-based double perovskite Cs2NaLuCl6 that enables efficient visible and near-infrared (NIR) emission, which stems from self-trapped exciton (STE) and Sm3+, respectively. Benefit from up to 72.89% energy transfer efficiency from STE to Sm3+ and high doping concentrations due to similar ionic activity between Sm3+ and Lu3+, thus eruptive PLQY of 74.58% in the visible light region and 23.12% in the NIR light region can be obtained. Moreover, Sb3+/Sm3+-codoped Cs2NaLuCl6 exhibits tunable emission characteristic in the visible light region under different excitation wavelengths, which can change from blue emission (254 nm excitation) to white emission (365 nm excitation). More particularly, only the NIR emission can be captured by the NIR camera when a 700 nm cutoff filter is added. The excellent stability and unique optical properties of Sb3+/Sm3+-codoped Cs2NaLuCl6 enable us to demonstrate its applications in NIR light-emitting diode, triple-mode fluorescence anti-counterfeiting and information encryption. These findings provide new inspiration for the application of rare earth-based double perovskite in optoelectronic devices.

Exploring the potential molecular mechanism of Gualou Guizhi decoction in the treatment of rheumatoid arthritis based on network pharmacology and molecular docking.

Traditional Chinese medicine (TCM) has been used in China for a long time and is gradually gaining more and more recognition worldwide. Gualou Guizhi Decoction (GGD) has long been used as a folk medicine for the treatment of rheumatic diseases, but its bioactive components and therapeutic mechanisms are still unclear. An integrated approach using network pharmacology and molecular docking and using methotrexate as a positive control drug. We obtained 157 active ingredients of GGD, 7542 RA disease targets and 49 intersecting targets. GO and KEGG enrichment analysis revealed that their functions were mainly related to cytokine active metal ion binding, enzyme binding and DNA binding, and enriched in TNF signaling pathway, T cell receptor signaling pathway, Toll-like receptor signaling pathway, RA pathway and other signaling pathways that are closely related to RA. The molecular docking results show that the effector components of GGD bind better to the core targets of RA, and some are even better than methotrexate. The therapeutic effect of GGD for RA is achieved by affecting the core targets such as VEGFA, IL-1β, IL6, CXCL8, CCL2, and JUN, which together interfere with the tumor necrosis factor signaling pathway and RA pathway to treat RA. The above study provides new ideas for further exploration of this classic formula in the future.

Mn2+ recycling in hypersaline wastewater: unnoticed intracellular biomineralization and pre-cultivation of immobilized bacteria.

Microbially induced manganese carbonate precipitation has been utilized for the treatment of wastewater containing manganese. In this study, Virgibacillus dokdonensis was used to remove manganese ions from an environment containing 5% NaCl. The results showed a significant decrease in carbonic anhydrase activity and concentrations of carbonate and bicarbonate ions with increasing manganese ion concentrations. However, the levels of humic acid analogues, polysaccharides, proteins, and DNA in EPS were significantly elevated compared to those in a manganese-free environment. The rhodochrosite exhibited a preferred growth orientation, abundant morphological features, organic elements including nitrogen, phosphorus, and sulfur, diverse protein secondary structures, as well as stable carbon isotopes displaying a stronger negative bias. The presence of manganese ions was found to enhance the levels of chemical bonds O-C=O and N-C=O in rhodochrosite. Additionally, manganese in rhodochrosite exhibited both + 2 and + 3 valence states. Rhodochrosite forms not only on the cell surface but also intracellularly. After being treated with free bacteria for 20days, the removal efficiency of manganese ions ranged from 88.4 to 93.2%, and reached a remarkable 100% on the 10th day when using bacteria immobilized on activated carbon fiber that had been pre-cultured for three days. The removal efficiency of manganese ions was significantly enhanced under the action of pre-cultured immobilized bacteria compared to non-pre-cultured immobilized bacteria. This study contributes to a comprehensive understanding of the mineralization mechanism of rhodochrosite, thereby providing an economically and environmentally sustainable biological approach for treating wastewater containing manganese.

Influence of proline and hydroxyproline as antimicrobial and anticancer peptide components on the silver(I) ion activity: structural and biological evaluation with a new theoretical and experimental SAR approach.

Silver(I) complexes with proline and hydroxyproline were synthesized and structurally characterized and crystal structure analysis shows that the formulas of the compounds are {[Ag2(Pro)2(NO3)]NO3}n (AgPro) (Pro = L-proline) and {[Ag2(Hyp)2(NO3)]NO3}n (AgHyp) (Hyp = trans-4-hydroxy-L-proline). Both complexes crystallize in the monoclinic lattice with space group P21 with a carboxylate bidentate-bridging coordination mode of the organic ligands Pro and Hyp (with NH2+ and COO- groups in zwitterionic form). Both complexes have a distorted seesaw (C2v) geometry around one silver(I) ion with τ4 values of 58% (AgPro) and 51% (AgHyp). Moreover, the results of spectral and thermal analyses correlate with the structural ones. 1H and 13C NMR spectra confirm the complexes species' presence in the DMSO biological testing medium and their stability in the time range of the bioassays. In addition, molar conductivity measurements indicate complexes' behaviour like 1 : 1 electrolytes. Both complexes showed higher or the same antibacterial activity against Bacillus cereus, Pseudomonas aeruginosa and Staphylococcus aureus as AgNO3 (MIC = 0.063 mM) and higher than silver(I) sulfadiazine (AgSD) (MIC > 0.5 mM) against Pseudomonas aeruginosa. In addition, complex AgPro exerted a strong cytotoxic effect against the tested MDA-MB-231 and Jurkat cancer cell lines (IC50 values equal to 3.7 and 3.0 μM, respectively) compared with AgNO3 (IC50 = 6.1 (5.7) μM) and even significantly higher selectivity than cisplatin (cisPt) against MDA-MB-231 cancer cell lines (SI = 3.05 (AgPro); 1.16 (cisPt), SI - selectivity index). The binding constants and the number of binding sites (n) of AgPro and AgHyp complexes with bovine serum albumin (BSA) were determined at four different temperatures, and the zeta potential of BSA in the presence of silver(I) complexes was also measured. The in ovo method shows the safety of the topical and intravenous application of AgPro and AgHyp. Moreover, the complexes' bioavailability was verified by lipophilicity evaluation from the experimental and theoretical points of view.

Overcoming passivation through improved mass transport in dense ionic fluids.

Deep Eutectic Solvents (DESs) have recently been shown to be part of a dense ionic fluid continuum between ionic liquids and concentrated aqueous brines. Charge transport was shown to be governed by fluidity, with no discontinuity between molar conductivity and fluidity irrespective of cation, charge density or ionic radius. By adjusting the activity of water and chloride ions, mass transport, speciation and reactivity can be altered. It has been shown that while brines provide a high chloride content at a lower viscosity than DESs, unlike DESs, brines are unable to prevent metal passivation due to their high water content. This results in the possibility to impart a level of selectivity towards metal dissolution (or passivation) when processing mixed metal materials. Forced convection can be used to avoid the issue of slow mass transport in viscous media, and the use of jets or targeted ultrasound are effective methods for overcoming this issue. High-powered ultrasound was applied to copper, cobalt, and aluminium electrodes undergoing anodic dissolution, and linear sweep voltammetry showed a linear current-voltage response at potentials anodic of the oxidation potential under sonication, with total charge passed being 5 to 134 times greater than under silent conditions. Application of ultrasound to silver and nickel electrodes displayed an initial linear current-voltage response, but the increased water content of the brines resulted in passivation. Mass transport throughout the bulk solution is governed by the forced convection imparted by the ultrasound and ionic species must only migrate across the electrical double layer. It is shown that the anodic dissolution of a range of metals classically expected to passivate, e.g. aluminium, can be significantly accelerated under insonation conditions.

Optimization of the Extraction Process of Bioactive Compounds from Zingiber officinale Roscoe, Evaluation of Acetylcholinesterase Enzyme Inhibition and Cytotoxic Activity of the Free and Encapsulated Extract

The present study optimized the extraction process of bioactive compounds present in ginger (Zingiber officinale) dried at 80 °C, using ethanol:water 70:30 (v/v) as solvent. The extracts were evaluated for antioxidant activity by the 2,2’-azino-bis(3-ethylbenzothiazoline6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical reduction methods and by the chelating activity of FeII ions. It was found that the extraction condition with a temperature of 60 °C and an extraction time of 12 h showed better responses to the tests. Then, the characterization of the compounds was carried out by mass spectrometry and thermal analysis (thermogravimetric (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC)), identifying that the main compounds of ginger were gingerols and shogaols, being confirmed by the intensities and characteristics of the thermal graphs. The inhibition of the enzyme acetylcholinesterase (AChE) was evaluated using the Ellman test, which did not show an inhibitory action. Regarding cytotoxic activity, the free extract and encapsulated in liposomes were tested, showing antiproliferative effect at different concentrations for human kidney tumor cells (786-0), liver cells (HUH7.5), and Macaca mullata normal kidney cells (LLC-MK2). Given the results obtained, ginger presents itself as a renewable source of bioactive compounds and can be indicated for applications in the pharmaceutical industry