Chloride Research Articles

Supramolecular Gels Based on C3-Symmetric Amides: Application in Anion-Sensing and Removal of Dyes from Water.

We modified C3-symmetric benzene-1,3,5-tris-amide (BTA) by introducing flexible linkers in order to generate an N-centered BTA (N-BTA) molecule. The N-BTA compound formed gels in alcohols and aqueous mixtures of high-polar solvents. Rheological studies showed that the DMSO/water (1:1, v/v) gels were mechanically stronger compared to other gels, and a similar trend was observed for thermal stability. Powder X-ray analysis of the xerogel obtained from various aqueous gels revealed that the packing modes of the gelators in these systems were similar. The stimuli-responsive properties of the N-BTA towards sodium/potassium salts indicated that the gel network collapsed in the presence of more nucleophilic anions such as cyanide, fluoride, and chloride salts at the MGC, but the gel network was intact when in contact with nitrate, sulphate, acetate, bromide, and iodide salts, indicating the anion-responsive properties of N-BTA gels. Anion-induced gel formation was observed for less nucleophilic anions below the MGC of N-BTA. The ability of N-BTA gels to act as an adsorbent for hazardous anionic and cationic dyes in water was evaluated. The results indicated that the ethanolic gels of N-BTA successfully absorbed methylene blue and methyl orange dyes from water. This work demonstrates the potential of the N-BTA gelator to act as a stimuli-responsive material and a promising candidate for water purification.

Effects of different cooling methods on the resistance to chloride ion penetration in concrete produced with slag-modified cement and exposed to elevated temperatures

The deterioration of reinforced concrete elements is associated with the ingress of aggressive agents through the concrete capillary pores. The exposure to elevated temperatures can be a serious concrete degradation factor, depending on its intensity and the cooling procedures. This paper presents a quantification of the effects of slow cooling (SC) and fast cooling (FC) methods on the chloride-ions penetration into fire-damaged concretes produced with a slag-modified cement. A (2 × 4 × 2) factorial experimental program was designed to evaluate the diffusion of chloride ions within different types of concrete (characteristic compressive strengths of 20 MPa and 35 MPa) before (25 °C) and after exposure to different high temperature levels (200 °C, 500 °C and 700 °C) and cooling procedures (SC and FC). Chloride diffusion coefficients were used to estimate the service life of the concretes and scanning electron microscopy was used to investigate the microstructural mechanisms behind the durability results. The exposure of concrete to high temperatures compromises its durability, as thermal cracking propagation and porosity increases tend to facilitate the penetration of aggressive agents and the diffusion of chloride ions. The use of the slag-modified cement did not provide significant benefits to the durability of concretes exposed to 200 °C and the effects of different cooling methods on the chloride ions permeability were very noticeable. In contrast, statistical analyses did not detect significant difference between the effects of SC and FC for concretes exposed to 500 °C or 700 °C.

Impact of Hydrostatic Pressure on Molecular Structure and Dynamics of the Sodium and Chloride Ions in Portlandite Nanopores.

In order to address the issues of energy depletion, more resources are being searched for in the deep sea. Therefore, research into how the deep-sea environment affects cement-based materials for underwater infrastructure is required. This paper examines the impact of ocean depth (0, 500, 1000, and 1500 m) on the ion interaction processes in concrete nanopores using molecular dynamics simulations. At the portlandite interface, the local structural and kinetic characteristics of ions and water molecules are examined. The findings show that the portlandite surface hydrophilicity is unaffected by increasing depth. The density profile and coordination number of ions alter as depth increases, and the diffusion speed noticeably decreases. The main cause of the ions' reduced diffusion velocity is expected to be the low temperature. This work offers a thorough understanding of the cement hydration products' microstructure in deep sea, which may help explain why cement-based underwater infrastructure deteriorates over time.

Probing iodide/iodonium salt interactions with single-walled carbon nanotubes for resilient electrochemical capacitor

Self-standing films from single-walled carbon nanotubes (SWCNTs) were successfully used as electrochemical capacitors’ (ECs) electrode material, which exhibited state-of-the-art characteristics. The surface of SWCNTs was modified by iodonium salt molecules that substantially and permanently improved their electrical conductivity. The addition of pyridinium iodine chloride salt (IPyCl) quadrupled the value of the electrical conductivity of the SWCNT film, which reached values as high as 1022 S cm−1. Subsequently, the electrochemical performance of the newly designed self-standing SWCNTs with deposited IPyCl in aqueous neutral 1 M Li2SO4 and redox-active 1 M KI electrolytes was thoroughly analysed. Because redox activity of iodine species was observed mainly on the positive electrode, activated carbon with a developed surface area was used as a negative electrode to balance the faradaic charge. Due to the notable stability of iodonium salt dopant (instead of labile halogen-containing compounds typically used for SWCNT doping), robust charge/discharge performance of EC was demonstrated (> 10 000 cycles) in Li2SO4 electrolyte. Moreover, a significant improvement of capacitor metrics (from 49 to 75 F g−1) was obtained when electrodes modified by previously unexplored iodonium salt were utilized in 1 M KI electrolyte. Extensive analysis of the obtained data led to the elucidation of the doping mechanism responsible for the aforementioned achievements. The novel SWCNT-based electrodes enhanced with iodonium salt are auspicious materials, which can be used to build EC systems of appreciable capacitance.

How does carbonation of alkali-activated slag and Portland cement systems impact steel corrosion differently?

Carbonation of cementitious materials, associated with neutralization of pore solution, is one of the prevalent reasons for inducing corrosion of steel in concrete. Compared with ordinary Portland cement (OPC) concrete, the poorer carbonation resistance of alkali-activated slag (AAS) concrete leads to serious durability concerns of a higher risk of steel corrosion. This work investigates the corrosion behaviors of steel embedded in intact and carbonated AAS and OPC mortars exposed to various relative humidity conditions, with the aim of fostering a better understanding of how carbonation impacts steel corrosion differently in these two cementitious systems. The results show that uncarbonated AAS mortars have better protective ability against corrosion than OPC counterparts; however, poorer performance after complete carbonation. It is mainly attributed to the combined effect of severe deterioration and coarsening of pore structure and increased ratio of chloride ion concentration to hydroxide ion concentration ([Cl−]/[OH−]) in pore solution, resulted from the consumption of hydroxide ions and release of bound chloride after carbonation. Besides, the different shifts of R-C (material resistivity versus corrosion rate) relationship lines in AAS and OPC mortars after carbonation are observed, which is ascribed to the different compositional and microstructural evolutions induced by carbonation in these two cementitious systems.

Benzotriazole loaded polypyrrole/cerium oxide synthesized composite blend within epoxy resin designed as superior coatings against mild steel oxidative corrosion in sodium chloride medium

In the present research work, benzotriazole or BTA-loaded polypyrrole/CeO2 (PCeB) coatings with different weight fractions as 0.5 %, 1.0 %, and 1.5 % blended with epoxy resin (EPR) were prepared and used to inspect the self-healing and corrosion protection behavior of the composite polypyrrole/CeO2 or PCe prior and after the loading of BTA. The synthesized composites were characterized structurally by XRD and FTIR studies and morphologically by SEM analysis. The surface topology of the coatings over mild steel was analyzed through SEM and AFM studies, furthered with the wettability/water resistance of coated surfaces through contact angle measurements, wherein BTA as inhibitor release rate was studied by the ultra-violet spectroscopy to assess the release amount of BTA within 220–400 nm. The corrosion protection of coated samples was evaluated by the potentiodynamic polarization method and electrochemical impedance spectroscopy or EIS, immersing the steel samples in 3.5 % NaCl solutions. There is a positive shift in Ecorr values and the composite PCeB/EPR (1 %) showed a stupendous protection efficiency of 99.95 % after 3 h immersion obtained through the EIS studies. These findings indicate that Polypyrrole/CeO2@BTA could be a potential substitute for persistent anticorrosive coatings for mild steel against aggressive chloride ions.

The Effects of Cl− and selected deoxidizers on the high temperature corrosion electrochemistry of alloy 690 in nuclear steam generator water

ABSTRACT The heat transfer tube in a steam generator serves as a critical heat exchange component in the primary and secondary loops of pressurized water reactor (PWR) nuclear power plants. The corrosion resistance of the heat transfer tube material directly influences the longevity of PWR nuclear power plants. This study investigated the electrochemical corrosion properties of 690 alloy (UNS N06690) in a simulated secondary water environment of PWR, focusing on different chloride ion concentrations and combinations of deoxidizers. The findings reveal a gradual decrease in the corrosion potential of 690 alloy, accompanied by an increase in self-corrosion current and a progressive reduction in the passivation range, ultimately leading to its disappearance as chloride ion concentration rises from 0 μg·L−1 to 500 μg·L−1. Moreover, the impedance value of the inner film exhibits a declining trend with increase of chloride ion concentration. Conversely, the resistance value of the outer film remains relatively stable while the size and spacing of oxide particles on the surface of the 690 alloy continuously increase. This observation suggests that chloride ions primarily influence the formation of the inner passivation film, which in turn determines the corrosion resistance of the 690 alloy. Notably, the performance of the 690 alloy is similar when the deoxidizer combination is ammonia(NH3)+erythorbic acid(ERA) or NH3+hydrazine(N2H4), demonstrating the ability to form a relatively complete passivation film and exhibit improved corrosion resistance compared to NH3+N-isopropyl hydroxylamine, additionally, when the deoxidizer combination is NH3+N2H4, the 690 alloy exhibits lower self-corrosion current density across different chloride ion concentrations, indicating enhanced corrosion resistance.

Strukturelle Einblicke in die Terpencyclasedomänen Zweier Pilzlicher Sesterterpensyntasen und Enzymengineering zur Diversifizierung von Sesterterpenen

AbstractÜber die Strukturen und katalytischen Mechanismen von Sesterterpensynthasen (StTSs) ist wenig bekannt, was das strukturbasierte Engineering von StTSs zur Erweiterung der strukturellen Diversität von Sesterterpenen erheblich erschwert. Wir berichten hier über die Kristallstrukturen der Terpencyclisierungsdomänen (TC) von zwei pilzlichen StTSs: der Sesterfisherol‐Synthase (NfSS) und der Sesterbrasiliatrien‐Synthase (PbSS). Beide TC‐Strukturen enthalten Benzyltriethylammoniumchlorid (BTAC), Pyrophosphat (PPi) und Magnesiumionen (Mg2+), wodurch die katalytisch aktiven Zentren klar definiert sind. Eine Kombination aus Theorie und Experimenten, einschließlich der Modellierung carbokationischer Intermediate, ortsgerichteter Mutagenese und Isotopenmarkierungen, lieferte detaillierte Einblicke in die strukturellen Grundlagen der katalytischen Mechanismen. Strukturbasiertes Engineering von NfSS und PbSS führte zur Bildung von 20 Sesterterpenen, darunter 13 neue Verbindungen und vier Epimerpaare mit unterschiedlichen Konfigurationen an C18. Diese Ergebnisse erweitern die strukturelle Vielfalt von Sesterterpenen und liefern wichtige Erkenntnisse für die zukünftige Forschung im Bereich der synthetischen Biologie.

Theoretical study of adsorption of sodium, lithium, magnesium and calcium chloride and sulfate salts by pure and Sc-doped B12N12 nanocages and pure boron nitride nanosheet

High concentrations of water-soluble chloride and sulfate salts may cause adverse effects to humans and plants. Boron nitride (BN) nanostructures seem able to remove these water-soluble salts. In addition, Li+, Mg2+, Ca2+, and Na2+ interactions with BN nanostructures have received much attention in fabricating high-performance metal-ion batteries. Accordingly, this study investigated the adsorption of chloride and sulfate salts of Li, Mg, Ca, and Na on pristine and scandium (Sc)-doped B12N12 nanocages and pure BN nanosheet through DFT calculations. Optimizing the structures at the B3LYP/6-31 g (d, p) and M062X/6-311 g (d, p) computational levels indicated very exothermic chemisorption of chloride and sulfate salts on the pure and Sc-doped B12N12 nanocages. The B12N12-LiCl and Sc@B11N12-LiCl complexes showed the highest negative adsorption energies of −26.33 and −57.30 kcal/mol among the chloride salts. The B12N12-MgSO4 and Sc@B12N12-MgSO4 complexes showed the highest adsorption energies of −69.27 and −102.70 kcal/mol among the sulfate salts. Studying the effect of the adsorption process on the electronic properties of the B12N12 nanocage showed a reduction in the energy gap upon the adsorption of all salts on the pure B12N12 nanocage with the lowest energy gap of 3.98 eV for B12N12-MgSO4. The adsorption energies of the individual salts and their complexes on the B12N12 nanosheet at the B3LYP/6-311 g (d, p) level imply the occurrence of physisorption. A significant reduction was observed in the energy gap by adsorbing the salts on the BN nanosheet. Adsorbing CaSO4 and MgSO4 on the BN nanosheet caused the largest variation of 1.71 and 1.56 eV in the energy gap, respectively. The promising results of our study highlight the potential application of BN nanostructures in the removal of various soluble salts and the fabrication of metal-ion batteries.

The role of serum chloride ion in the prognosis of COPD

Background: As exacerbations of chronic obstructive pulmonary disease (COPD) are one of the leading causes of hospitalization and are associated with significant mortality, it is particularly important to accurately assess the risk of exacerbations in COPD. Most of the current clinical biomarkers are related to inflammation and few consider how ion levels affect COPD. While chloride ions, the second most abundant serum electrolyte, have been shown to be associated with poor prognosis in several diseases, but their relationship with COPD remains unclear. Methods: In total, 105 patients with acute exacerbations of COPD were recruited. Data on clinical characteristics, lung function, blood count, blood biochemistry, relevant scales including the Clinical COPD Questionnaire (CCQ), BODE (BMI, airflow obstruction, dyspnea, exercise capacity) index and the St George's Respiratory Questionnaire (SGRQ) were collected from all patients for statistical analysis. Result: There were significant differences in lung function indicators and disease severity in the low chloride ion subgroup compared with the high chloride ion subgroup. On multiple logistic regression analysis, chloride ion was an independent factor affecting lung function in COPD patients (OR= 0.823, 95% CI: 0.730 - 0.929, p=0.002). The sensitivity of chloride ion in predicting COPD severity was 78%, the specificity was 63% and the area under the curve was 0.724 (p < 0.001). Subgroup analysis showed that chloride ion was a stronger predictor in male, smoking patients. Conclusions: Chloride ion is a novel prognostic biomarker for COPD, and low levels of chloride ion are independently associated with exacerbations in COPD patients.

High-sensitivity and energy-efficient chloride ion sensors based on flexible printed carbon nanotube thin-film transistors for wearable electronics

The advent of flexible single-walled carbon nanotube thin-film transistors (SWCNT-TFTs) has transformed electronics, providing significant benefits like low operating voltage, reduced power consumption, cost-effectiveness, and improved signal amplification. This study focuses on leveraging these attributes to develop a novel flexible high-sensitivity and energy-efficient chloride ion sensors based on printed flexible SWCNT-TFTs utilizing polymers-sorted semiconducting SWCNTs (sc-SWCNTs) as the active layers and ion liquids-poly(4-vinylphenol as dielectric layers along with the evaporated deposition of aluminum electrodes and printed silver electrodes as the gate and source-drain electrodes, respectively. The sensors exhibit several operational advantages, including low voltage requirements (≤1 V), rapid response speed (5.32 s), significant signal amplification (Up to 702.6%), low power consumption (0.31 μJ at 1 mmol chloride ion), good repeatability, high sensitivity for both low and high concentrations of chloride ion (up to 100 mmol/L) and excellent mechanical flexibility (No obvious changes after bending for 10,000 times with a 5 mm radius). The detection mechanism of chloride ions was analyzed using X-ray Photoelectron Spectroscopy (XPS). It was found that chloride ions react with silver nanoparticles (AgNPs) to form silver chloride (AgCl) on printed electrodes, impeding carrier transport and reducing the currents in SWCNT TFTs. Importantly, our sensors' compatibility with smart devices allows for real-time monitoring of chloride ion levels in human sweat, offering significant potential for daily health monitoring.

Constructing in-situ polymerized electrolyte for room-temperature solid-state chloride ion battery with enhanced electrochemical performance

Considering large volume variation and dissolution issues of some promising electrode materials for chloride ion batteries (CIB), the construction of solid polymer electrolytes (SPE) for efficient chloride ion transport is intriguing. However, this is hindered by low ionic conductivity of chloride SPEs and poor cycling performance of CIBs. Herein, an in-situ polymerized and cross-linked poly(ethylene glycol) diacrylate-based chloride SPE with a low plasticizer content of succinonitrile is designed, yielding a room-temperature ionic conductivity of 7.6 × 10−5 S cm−1, which is higher than that of previously reported SPEs for CIBs. Moreover, the use of the as-prepared SPE achieves an integrated organic cathode with significantly enhanced rate performance and capacity retention of 96.1% after 100 cycles at room temperature, which is much higher than 49.9% (80 cycles) of the cathode in the CIB with a sandwiched structure. These improved performance is also superior to that of other reported cathodes coupled with different chloride SPEs. The chloride ion transfer mechanism of the cathode is revealed by X-ray photoelectron spectroscopy and energy dispersive spectroscopy.

Modeling electrochemical chloride extraction in surface carbonated concrete

This paper investigated the Electrochemical Chloride Extraction (ECE) process in concrete with carbonated surface layers. First, the ECE model for surface carbonated concrete was proposed based on pore size distribution function. Subsequently, to validate the model, concrete cube specimens exposed to natural coastal environments were modified and designed for ECE tests. Based on the validated ECE model, parametric studies were conducted. Parametric studies show that increasing the thickness of the surface carbonation layer up to 20 mm leads to a 57% increase in extraction duration, whereas the thickness of the partially carbonated zone has a relatively minor impact on the ECE process. The parametric study shows that the surface carbonated zone will pose hindrances to the extraction of chloride ions. Due to the simultaneous presence of concrete carbonation and chloride ion ingress in the actual marine atmospheric environment, considering the actual carbonation depth is of significant importance for predicting chloride ion migration during Electrochemical Chloride Extraction.

White-green photoluminescence of manganese(II) complexes with pyrazolo[1,5-a][1,10]phenanthroline-3-carbonitrile

Five manganese(II) complexes with a bidentate pyrazolo[1,5-a][1,10]phenanthroline-3-carbonitrile ligand (L) have been prepared and their structures have been determined. The anion effect on the structural diversity of the complexes has been studied using manganese(II) salts with different anions such as Cl¯, ClO4¯, and Ts¯. A reaction between manganese(II) chloride and L in organic solvents leads to complexes [MnL2Cl2]·xCH2Cl2 (1) and [Mn2L2(H2O)Cl4]·L (2), the use of manganese(II) tosylate in the rection yields in [MnL(H2O)3Ts]Ts·L·H2O (3) and [MnL(H2O)3Ts]Ts (4), and finally, in the case of manganese(II) perchlorate [MnL2(H2O)2](ClO4)2·L (5) is formed. According to the single-crystal X-ray analysis the coordination environment of the Mn(II) ions in the complexes is a distorted octahedron with MnN4Cl2 (1), MnN2O4 (3) and MnN4O2 (5) chromophores; the complex 2 is binuclear, in which two manganese atoms have different coordination geometries – distorted octahedron (MnN2Cl3O) and square pyramid (MnN2Cl3). Chloride ions are coordinated anions; perchlorate ions are in the outer coordination sphere. Tosylate ions can play both coordinating and non-coordinating roles in complexes. X-ray analysis shows that in 2 and 5 one molecule of L has no bonds with manganese atoms, and reveals only intermolecular interactions through π-π stacking. This leads to the formation of cocrystals [Mn2L2(H2O)Cl4]·L or [MnL2(H2O)2](ClO4)2·L, that affects the photophysical properties of these compounds. In order to compare the effect of L coordination on the photoluminescence properties of manganese(II) complexes, the complexes [Mn(phen)3](ClO4)2·xSolv with unsubstituted 1,10-phenanthroline have been synthesized. In contrast to [MnL2(H2O)2](ClO4)2·L, the 1,10-phenanthroline-based compound [Mn(phen)3](ClO4)2·H2O has no emission. Complexes 1, 3, 4 and 5 exhibit a white-green emission in the microsecond range with maxima at 530–565 nm in the solid state, and the photoluminescence properties of 5 are studied in solution.

Corrosion behavior of modified cement-based coated steel rebar subjected to different levels of tensile loads

Polymer-modified cement-based coating can provide corrosion protection for steel rebar. However, after the action of the tensile load, the connection between the polymer and the cement matrix was weakened, thus reducing its corrosion resistance. In this study, silica fume, nano-SiO2, and corrosion inhibitor were used to modify EVA (Ethylene Vinyl Acetate Copolymer) and cement-based coatings. Electrochemical experiments were used to evaluate the corrosion behavior of coated steel rebar after the action of different levels of tensile loads, and microscopic characterization and porosity experiments were applied to analyze the changes of microscopic properties of the coatings. The experimental results show that silica fume and nano-SiO2 produce more high-strength C-S-H gels through hydration reaction to improve the tensile properties and compactness of the coating, thus reducing the porosity and chloride ion permeability of the coating after tension. Tetrabasic-modified cement-based coated steel rebar with EVA, silica fume, nano-SiO2, and amino-alcohol corrosion inhibitor displayed the highest coating resistance and the lowest corrosion current density under the action of tensile load. Experimental results proves that nano-SiO2 enhances the tensile properties of the coating. The addition of corrosion inhibitor can further improve the compactness of the coating under tension, hinder the formation of chloride ion transport channel, and adsorb on the surface of steel rebar to improve the corrosion resistance of steel rebar.

PDDA-modified nanoflower-like BiOCl/MXene hybrid electrode for efficient capacitive deionization dichlorination

Currently, chloride ions in industrial water limits its reuse when extending the circulating water cycle. Therefore, it is necessary to remove Cl− to ensure its effective reuse. Considering the development of new materials for efficient electrochemical chloride removal is a key issue limiting the development of capacitive deionization technology for chlorine removal. In this study, BiOCl was grown in situ on the surface of V-MXene, and then a nanoflower-like BiOCl/MXene composite was synthesized by utilizing the properties of MXene as a structure-directing agent to modulate the morphology, which exhibits superior pore structure and specific capacitance. The poly (diallyl dimethylammonium) (PDDA) modification improved the materials’ specific capacitance and reduced energy consumption for dichlorination. The optimal BMP-10 exhibited superior performance for dichlorination, the maximum dichlorination capacity and rate were 161.64 mg g−1 and 2.20mg g−1 min−1. We found that MXene has excellent properties for exfoliation and morphology modulation of layered materials. Additionally, the electrical properties have an important influence on the electrochemical removal of chloride ions. Here we successfully synthesized an efficient electrode material with unique morphological structure for CDI dichlorination and provided ideas for structure-directing agents and electrical modulation in material design for electrochemical dichlorination.

Accelerated removal of organic pollutants by biochar-based iron carbon granule-activated periodate in chloride-containing water: The role of active chlorine

Ubiquitous in water environments, the chloride ion (Cl−) can impact the decontamination capacity of an oxidation system. However, minimal studies are available on its effects in periodate (PI)-based advanced oxidation processes. In this study, a novel biochar-based iron-carbon (FeBC) granule was synthesized to activate PI and remove organic pollutants from water containing Cl−. The FeBC/PI/Cl− system (FeBC: 0.5 g/L; PI: 0.5 mM; AO7: 20 mg/L; NaCl: 50 mM) exhibited excellent performance on various organic pollutants, with ˃ 85 % of Acid Orange (AO7) removal over a pH range of 3–10. Within 20 min after the tenth run, approximately 80 % of AO7 was removed. Inorganic ions and natural organic matter had a negligible effect on AO7 removal. Characterization results confirmed that the presence of Cl− enhanced Fe corrosion, thereby improving PI activation efficiency for removing AO7. Electron paramagnetic resonance spectroscopy and active species trapping experiments verified that radicals (•OH and O2•−) and nonradical (1O2, Fe(IV), and electron transfer) oxidation processes participated in the FeBC/PI system. Moreover, the presence of Cl− accelerated •OH, O2•−, 1O2, and Fe(IV) formation and generated active chlorine, such as HOCl. The main pathways involved in the generation of multiple reactive species were evaluated. AO7 degradation pathways were proposed, and numerous intermediates exhibited decreased toxicity. These findings provide new insights for the decontamination of organic contaminants in water containing Cl−.

The role of the STAS domain in SLC26A9 for chloride ion transporter function

The anion exchanger solute carrier family 26 (SLC26)A9, consisting of the transmembrane (TM) domain and the cytoplasmic STAS domain, plays an essential role in regulating chloride transport across cell membranes. Recent studies have indicated that C-terminal helices block the entrance of the putative ion transport pathway. However, the precise functions of the STAS domain and C-terminal helix, as well as the underlying molecular mechanisms governing the transport process, remain poorly understood. In this study, we performed molecular dynamics simulations of three distinct models of human SLC26A9, full-length, STAS domain removal (ΔSTAS), and C-terminus removal (ΔC), to investigate their conformational dynamics and ion-binding properties. Stable binding of ions to the binding sites was exclusively observed in the ΔC model in these simulations. Comparing the full-length and ΔC simulations, the ΔC model displayed enhanced motion of the STAS domain. Furthermore, comparing the ΔSTAS and ΔC simulations, the ΔSTAS simulation failed to exhibit stable ion bindings to the sites despite the absence of the C-terminus blocking the ion transmission pathway in both systems. These results suggest that the removal of the C-terminus not only unblocks the access of ions to the permeation pathway but also triggers STAS domain motion, gating the TM domain to promote ions’ entry into their binding site. Further analysis revealed that the asymmetric motion of the STAS domain leads to the expansion of the ion permeation pathway within the TM domain, resulting in the stiffening of the flexible TM12 helix near the ion-binding site. This structural change in the TM12 helix stabilizes chloride ion binding, which is essential for SLC26A9’s alternate-access mechanism. Overall, our study provides new insights into the molecular mechanisms of SLC26A9 transport and may pave the way for the development of novel treatments for diseases associated with dysregulated ion transport.

Strong and tough conductive hydrogels via an amphiphilic macromolecular crosslinker for flexible strain sensor

The strength and toughness of hydrogel are usually achieved through the synergy of chemical cross-linking and physical cross-linking from multi-component contributions. However, there are few reports on hydrogels that rely on a single component to obtain two cross-linked structures. Herein, we successfully synthesized an amphiphilic macromolecular crosslinker (polyoxyethylene 20 oleyl ether acrylate (O20AC)), and introduced it into a system composed of acrylamide (AAm), sodium chloride (NaCl) and water to prepare the P(AAm-O20AC)/NaCl hydrogel with high strength, outstanding toughness, and excellent good conductivity. Notably, the O20AC possess both crosslinker properties, which not only provide hydrogels with a stable chemical cross-linking network, but also its long hydrophobic chain act as physical crosslinking points to give the hydrogel a new pathway of energy dissipation.Depending on the O20AC crosslinker, the P(AAm-O20AC)/NaCl hydrogels exhibit good strength (tensile stress 714.46 kPa), toughness (elongation at break 3005 %), and fatigue resistance (overlap of hysteresis curves in repeated loading–unloading cycles). Besides, the existence of sodium ions and chloride ions also provides the hydrogel with highly sensitive deformation-dependent conductivity (GF is 5.8 in the 400 %-500 % strain range). Collectively, the strategy of preparing chemical and physical double-crosslinked hydrogels by amphiphilic O20AC will provide a bran-new insights for the development of hydrogel sensing materials.

B-diketon Derived Ligands Metal Complexes, Synthesize, Characterization, and Bioactivity Studies

The precursor in our study 2, 2’- ((1E,1’E) - (4,4’- diamino - 5, 5’- dimethyl - [1,1’-biphenyl]-3, 3’-diyl) bis(diazene-2,1-diyl) diphenol (W1) or (W2) 3,3’-dimethyl-5,5’-bis((E)-pyridin-3-yldiazenyl)-[1,1’-biphenyl]-4,4’-diamine were obtained from reaction of diazonium salt with tolidin. The both precursors used for synthesis of the ligands [H4L1] and [H2L2] by reaction with di benzyl methan to produce the ligands [H4L1]2,2’-((1E,1’E)-(4,4’-bis((3-hydroxy-1,3-diphenylpropylidene)amino)-5,5’-dimethyl-[1,1’-biphenyl]-3,3’-diyl)bis(diazene-2,1-diyl))diphenoland [H2L2] 3,3’-((3,3’-dimethyl-5,5’-bis((E)-pyridin-3-yldiazenyl)-[1,1’-biphenyl]-4,4’-diyl)bis(azaneylylidene))bis(1,3-diphenylpropan-1-ol). Elemental microanalysis, 1H and 13C-NMR, FT-IR, U.V, mass spectroscopies were used to describe the structure of the ligands. In this research we also reported the complexes synthesis via reaction of of [NiII, MnII, CoII, CdII, CuII] chloride salts with ligands, using KOH as a base and ethanol as a solvent, under reflux. Complexes were characterized by atomic absorption, (FT-I.R, U.V-Vis, 1H and 13C-NMR and mass) spectroscopies along with conductivity, magnetic susceptibility and melting point measurements. The presence of crystallized water molecule insured by thermal analysis in some complexes structure. Finally, the synthesized ligands and complexes biological activity studied against selected organisms.