Accumulation Of Chloride Ions Research Articles

GhCLCc-1, a Chloride Channel Gene from Upland Cotton, Positively Regulates Salt Tolerance by Modulating the Accumulation of Chloride Ions.

The ionic toxicity induced by salinization has adverse effects on the growth and development of crops. However, researches on ionic toxicity and salt tolerance in plants have focused primarily on cations such as sodium ions (Na+), with very limited studies on chloride ions (Cl-). Here, we cloned the homologous genes of Arabidopsis thaliana AtCLCc, GhCLCc-1A/D, from upland cotton (Gossypium hirsutum), which were significantly induced by NaCl or KCl treatments. Subcellular localization showed that GhCLCc-1A/D were both localized to the tonoplast. Complementation of Arabidopsis atclcc mutant with GhCLCc-1 rescued its salt-sensitive phenotype. In addition, the silencing of the GhCLCc-1 gene led to an increased accumulation of Cl- in the roots, stems, and leaves of cotton seedlings under salt treatments, resulting in compromised salt tolerance. And ectopic expression of the GhCLCc-1 gene in Arabidopsis reduced the accumulation of Cl- in transgenic lines under salt treatments, thereby enhancing salt tolerance. These findings elucidate that GhCLCc-1 positively regulates salt tolerance by modulating Cl- accumulation and could be a potential target gene for improving salt tolerance in plants.

Rootstock varietal ability in accumulation of chloride ions underpins improved physiology and metabolism of grapevine exposed to salinity

Soil salinity limits plant growth, affects crop production and nutrition, and endangers food security globally. The use of salt-tolerant rootstocks has proven to be an efficient strategy to alleviate the adverse effects of salinity in different crop species including Vitis vinferae. The long-term response to salinity of three grapevine rootstock varieties, Paulsen 1103 (P1103), Richter 110 (R110), and Sélection Oppenheim 4 (SO4), was tested in pots with drip irrigation at different NaCl concentrations (0, 10 mM, and 30 mM) for 82 days. During the experiment, plant morphology, physiology, and central metabolism were monitored. The results revealed that shoot growth, including stem diameter and fresh and dry weight of stems and leaves, was significantly restricted by salinity in P1103 and SO4, less in R110. Roots were more sensitive than shoots to salinity, showing significant reductions in biomass already at 10 mM NaCl. The high salinity level markedly reduced most of the photosynthetic traits measured in P1103 and R110. In contrast, SO4 was exceptionally stable from a physiological standpoint, while having the lowest chloride contents in its leaves compared to the other two varieties when exposed to salinity. Elemental analysis and GC-MS based metabolite profiling of the leaves exposed to a salt stress revealed a shift in carbon (C) and nitrogen (N) metabolism, reflected by a decreased C: N ratio and by a lower content of organic acids (e.g. succinate, malate, and citrate) likely supporting the measured accumulation of amino acids (e.g. GABA, glutamate, and proline) in P1103 and R110. In addition, correlation-based network analysis (CNA) of the metabolic data revealed increased coordination of metabolic processes under salinity than under control conditions. CNA also showed higher alteration in the metabolic network in P1103 and R110 than in SO4. Taken together, the results reveal that SO4 showed milder alteration in its photosynthetic and metabolic response to saline conditions, in association with lower Cl−accumulation in its leaves.

Investigating the chloride ion resistance of cracked concrete through Reverse-seepage and Saturation based Action Anti-corrosion Tech (RS-AAT): Experimental and numerical analysis

This study investigates the chloride ions transport in cracked concrete with the impact of RS-AAT (Reverse-seepage and Saturation based Action Anti-corrosion Tech) in the environment of wet-dry cycling and soaking conditions. With the effect of reverse water pressure, the chloride ions accumulation surrounding the crack on the concrete surface and the chloride ions penetration within the concrete along the cracks are demonstrated by the indoor experiments. A two-dimensional convective diffusion model of chloride ions in cracked concrete is established to simulate the correlation between crack size and the change of reverse water pressure. Four types of cracks with widths of 0 mm, 0.2 mm, 0.4 mm and 1 mm, and a depth of 20 mm were selected. Three types of water pressures with values of 0.2 MPa, 0.3 MPa and 0.4 MPa were used for the technique. The experimental results show that the anti-convection effect induced by the reverse water pressure can inhibit the accumulation of chloride ions around the cracks and effectively limit the intrusion of chloride ions into the concrete protection layer. With the increase of reverse water pressure, the inhibition effect of seepage flow on chloride ions is more obvious. The experimental findings provide valuable references for investigating marine concrete durability and resistance to chloride ion erosion.

Paclitaxel induces pyroptosis by inhibiting the volume‑sensitive chloride channel leucine‑rich repeat‑containing 8a in ovarian cancer cells.

Pyroptosis is a newly identified form of cell death, morphologically characterized by excessive cell swelling. In the present study, paclitaxel (PTX) combined with platinum were used as first‑line chemotherapy, against ovarian cancer cells by inducing multiple types of cell death. However, it remains unclear whether PTX can induce pyroptosis in ovarian cancer cells. It was recently reported that PTX inhibited chloride channels, an inhibition known to cause cell swelling. In the present study, it was first verified that pyroptosis‑like cell death, as well as cleaved‑caspase‑3 and cleaved‑gasdermin E (GSDME) were induced by PTX in A2780 ovarian cancer cells. PTX inhibited the background‑ and hypotonicity‑activated chloride currents, promoted intracellular chloride ion accumulation, those manifestations are similar to those of the classic volume‑regulatory anion channel (VRAC) blocker, 4‑(2‑butyl‑6,7‑dichloro‑2‑cy-clopentyl‑indan‑1‑on5‑yl) oxobutyric acid (DCPIB). Of note, both DCPIB and the downregulation of VRAC constituent protein leucine‑rich repeat‑containing 8a themselves could not induce persisted cell swelling and pyroptosis‑like phenotypes. However, they could enhance the effects of PTX in inducing pyroptosis‑like phenotypes, such as marked cell swelling, cell membrane rupture and excessive activation of caspase‑3 and GSDME N‑terminal fragment, which ultimately caused marked pyroptosis in A2780 cells. These findings revealed a potential mechanism of PTX and offered new insights into the effects of a synergistical combination of PTX and VRACs blockers in ovarian cancer chemotherapy.

River water influenced by shale gas wastewater discharge for paddy irrigation has limited effects on soil properties and microbial communities

The processes of hydraulic fracturing to extract shale gas generate a large amount of wastewater, and the potential impacts of wastewater discharge after treatment are concerning. In this field study, we investigated the effects of the irrigation of paddy fields for 2 consecutive years by river water that has been influenced by shale gas wastewater discharge on soil physicochemical properties, microbial community structure and function, and rice grain quality. The results showed that conductivity, chloride and sulfate ions in paddy soils downstream of the outfall showed an accumulative trend after two years of irrigation, but these changes occurred on a small scale (<500 m). Two-year irrigation did not cause the accumulation of trace metals (barium, cadmium, chromium, copper, lead, strontium, zinc, nickel, and uranium) in soil and rice grains. Among all soil parameters, the accumulation of chloride ions was the most pronounced, with concentrations in the paddy soil at the discharge site 13.3 times higher than at the upstream control site. The use of influenced river water for paddy irrigation positively increased the soil microbial diversity, but these changes occurred after two years of irrigation and did not occur after one year of irrigation. Overall, the use of river water affected by shale gas wastewater discharge for agricultural irrigation has limited effects on agroecosystems over a short period. Nevertheless, the possible negative effects of contaminant accumulation in soil and rice caused by longer-term irrigation should be seriously considered.

Loss of endothelial CFTR drives barrier failure and edema formation in lung infection and can be targeted by CFTR potentiation

Pneumonia is the most common cause of the acute respiratory distress syndrome (ARDS). Here, we identified loss of endothelial cystic fibrosis transmembrane conductance regulator (CFTR) as an important pathomechanism leading to lung barrier failure in pneumonia-induced ARDS. CFTR was down-regulated after Streptococcus pneumoniae infection ex vivo or in vivo in human or murine lung tissue, respectively. Analysis of isolated perfused rat lungs revealed that CFTR inhibition increased endothelial permeability in parallel with intracellular chloride ion and calcium ion concentrations ([Cl-]i and [Ca2+]i). Inhibition of the chloride ion-sensitive with-no-lysine kinase 1 (WNK1) protein with tyrphostin 47 or WNK463 replicated the effect of CFTR inhibition on endothelial permeability and endothelial [Ca2+]i, whereas WNK1 activation by temozolomide attenuated it. Endothelial [Ca2+]i transients and permeability in response to inhibition of either CFTR or WNK1 were prevented by inhibition of the cation channel transient receptor potential vanilloid 4 (TRPV4). Mice deficient in Trpv4 (Trpv4-/-) developed less lung edema and protein leak than their wild-type littermates after infection with S. pneumoniae. The CFTR potentiator ivacaftor prevented lung CFTR loss, edema, and protein leak after S. pneumoniae infection in wild-type mice. In conclusion, lung infection caused loss of CFTR that promoted lung edema formation through intracellular chloride ion accumulation, inhibition of WNK1, and subsequent disinhibition of TRPV4, resulting in endothelial calcium ion influx and vascular barrier failure. Ivacaftor prevented CFTR loss in the lungs of mice with pneumonia and may, therefore, represent a possible therapeutic strategy in people suffering from ARDS due to severe pneumonia.

Failure analysis of cracking in the thin-walled pressure vessel of electric water heater

The inner tank is the kernel component of the electric water heater. However, the stress concentration and presence of corrosive media often result in premature failure of the weld area. In this paper, the leakage failure of the circumferential weld (C-Weld) of the DC01EK inner tank was analyzed by optical microscopy, scanning electron microscopy, energy dispersive spectrometer, and microhardness test. Quantitative calculations of stress distribution of the C-Weld were performed by finite element simulations. Results show that the fracture of the C-Weld was induced by stress corrosion cracking (SCC). The corrosion and crack propagation resistance of the C-Weld are worsened by the presence of coarse grains in HAZ. The high axial stress component generated by the superposition of welding residual stress and working stress is the main driving force of crack expansion. The presence of the root gap of the C-Weld leads to stress concentration, which is more likely to cause scaling and accumulation of chloride ions, resulting in crevice corrosion. Reducing the root gap of the C-Weld, decreasing the welding heat input, and using the butt joint instead of the lap joint are suggested to eliminate such failures.

GABA Receptors Can Depolarize the Neuronal Membrane Potential via Quantum Tunneling of Chloride Ions: A Quantum Mathematical Study.

GABA (gamma-aminobutyric acid) receptors represent the major inhibitory receptors in the nervous system and their inhibitory effects are mediated by the influx of chloride ions that tends to hyperpolarize the resting membrane potential. However, GABA receptors can depolarize the resting membrane potential and thus can also show excitatory effects in neurons. The major mechanism behind this depolarization is mainly attributed to the accumulation of chloride ions in the intracellular compartment. This accumulation leads to increase in the intracellular chloride concentration and depolarize the Nernst potential of chloride ions. When the membrane potential is relatively hyperpolarized, this will result in a chloride efflux instead of influx trying to reach their depolarized equilibrium potential. Here, we propose different mechanism based on a major consequence of quantum mechanics, which is quantum tunneling. The quantum tunneling model of ions is applied on GABA receptors and their corresponding chloride ions to show how chloride ions can depolarize the resting membrane potential. The quantum model states that intracellular chloride ions have higher quantum tunneling probability than extracellular chloride ions. This is attributed to the discrepancy in the kinetic energy between them. At physiological parameters, the quantum tunneling is negligible to the degree that chloride ions cannot depolarize the membrane potential. Under certain conditions such as early neuronal development, gain-of-function mutations, stroke and trauma that can lower the energy barrier of the closed gate of GABA receptors, the quantum tunneling is enhanced so that the chloride ions can depolarize the resting membrane potential. The major unique feature of the quantum tunneling mechanism is that the net efflux of chloride ions is attained without the need for intracellular accumulation of chloride ions as long as the energy barrier of the gate is reduced but still higher than the kinetic energy of the chloride ion as a condition for quantum tunneling to take place.

Ictal wavefront propagation in slices and simulations with conductance-based refractory density model.

The mechanisms determining ictal discharge (ID) propagation are still not clear. In the present study, we aimed to examine these mechanisms in animal and mathematical models of epileptiform activity. Using double-patch and extracellular potassium ion concentration recordings in rat hippocampal-cortical slices, we observed that IDs moved at a speed of about 1 mm/s or less. The mechanisms of such slow propagation have been studied with a mathematical, conductance-based refractory density (CBRD) model that describes the GABA- and glutamatergic neuronal populations’ interactions and ion dynamics in brain tissue. The modeling study reveals two main factors triggerring IDs: (i) increased interneuronal activity leading to chloride ion accumulation and a consequent depolarizing GABAergic effect and (ii) the elevation of extracellular potassium ion concentration. The local synaptic transmission followed by local potassium ion extrusion and GABA receptor-mediated chloride ion accumulation underlies the ID wavefront’s propagation. In contrast, potassium ion diffusion in the extracellular space is slower and does not affect ID’s speed. The short discharges, constituting the ID, propagate much faster than the ID front. The accumulation of sodium ions inside neurons due to their hyperactivity and glutamatergic currents boosts the Na+/K+ pump, which terminates the ID. Knowledge of the mechanism of ID generation and propagation contributes to the development of new treatments against epilepsy.

Experimental Study on Corrosion of Galfan‐Coated Full‐Locked Coil Ropes in a Natatorium Environment

Galfan‐coated full‐locked coil rope is widely applied in long‐span spatial structures because of its high strength and lightweight. However, the corrosion problem is relatively serious in the natatorium, which affects the structure’s durability. To deeply reveal the corrosion mechanism of Galfan‐coated cable, this study first measured the natatorium on‐site, and the results indicated that the natatorium environment can be simulated by a constant temperature and humidity environment in engineering. Then, the constant temperature and humidity corrosion test was carried out to simulate the corrosion of Galfan‐coated cable with a certain amount of chloride ions on the surface, and the early corrosion rate was obtained. Later, the neutral salt spray accelerated corrosion test was carried out to predict the corrosion rate of the cable in the natatorium environment in the middle and late periods. The specimens included no‐stress unprotected coating cable, high‐stress unprotected coating cable, and high‐stress protected coating cable. The results show that high stress will accelerate the corrosion, and a protective coating can effectively prevent the corrosion. Finally, the linear model, bilinear model, and bilinear model considering chloride ion accumulation were proposed to study the corrosion of the Galfan coating. The results show that the linear model overestimates the corrosion rate, and the bilinear model and bilinear model considering chloride ion accumulation are practical. Meanwhile, corresponding maintenance suggestions were given for the natatorium project to improve the structure's durability.

Influence of salinity on the heterogeneous catalytic ozonation process: Implications to treatment of high salinity wastewater

The heterogeneous catalytic ozonation process is a promising treatment option for high salinity reverse osmosis concentrate (ROC) however the influence of salts on the catalyst performance is not well understood. In this work, we investigate the effect of salts on the performance of the catalytic ozonation process for treatment of synthetic ROC using a commercially available Fe-loaded Al2O3 catalyst. Our results show that the presence of salts influences the rate and extent of degradation of organic compounds present in the synthetic ROC when subjected to the heterogeneous catalytic ozonation process. Scavenging of aqueous O3 by chloride ions and/or transformation of organics (particularly humics) to more hydrophobic form as a result of charge shielding between adjacent functional groups and/or intramolecular binding by cations inhibits the bulk oxidation of organics to a measurable extent. While the scavenging of aqueous hydroxyl radicals at the salt concentrations investigated here was minimal, the accumulation of chloride ions in the electric double layer near the catalyst surface, particularly when pH< pHpzc, results in more significant scavenging of surface associated hydroxyl radicals. Overall, the presence of salts (particularly chloride ions) has a significant influence on the performance of both conventional and catalytic ozonation processes with some scope to mitigate this effect through appropriate choice of catalyst.

Experimental and numerical analysis of chloride transport in finite concrete under reverse water pressure

This paper investigates chloride ion convection–diffusion transport in the finite RC structure under reverse water pressures. The chloride ion penetration in concrete is examined experimentally and theoretically. One-dimensional experiments are designed to reveal the characters of the time-varied behaviors of surface chloride ion concentration and the chloride ion penetration under different reverse water pressure in the concrete. A numerical solution of the chloride ion convection–diffusion penetration is also established by finite element method (i.e., FEM) via software entitled COMSOL Multiphysics. The K-C model is attempted to be used for the assess of the permeability of concrete. The results suggest that the reverse water pressure can weaken the accumulation of chloride ion on the concrete surface and effectively prevent the chloride ions from invading into the concrete. The results of this paper offer much-needed insights into this growing discussion in the field of assess of durability of finite marine RC structure.

Effect of aggregates spatial distribution on three-dimensional transport of chloride ions in reinforced concrete

The spatial distribution of coarse aggregates directly affects the three-dimensional transport of chloride ions and the accumulation of chloride ions on the surface of steel bar in reinforced concrete. The meso-structure of a concrete specimen was recognized through X-ray CT technology. In considering the diffusion of chloride ions both in mortar matrix and ITZs, a three-dimensional transmission model was established to numerically simulate the diffusion of chloride ions in concrete, which was furtherly verified by electronic microprobe technology. To avoid the correlation of data, 100 sets of independent three-dimensional numerical samples were generated with real coarse aggregates extracted from concrete specimen. The influence of spatial distribution of coarse aggregates on diffusion of chloride ions was statistically analyzed, and the differences between three-dimensional transmission and two-dimensional transmission of same sections were studied. The research shows that the special distribution of coarse aggregates can cause the non-uniform distribution of chloride ions both in spatial and time scale. The concentration distribution of chloride ions satisfies the Normal distribution through Kolmogorov-Smirnov test and Chi-square test. For two-dimensional and three-dimensional transmission, the greater the depth, the greater the differences in calculation results.

Visualization of pH and Cl− Distributions inside Crevice of Type 430 Stainless Steel

The decrease in pH caused by the hydrolysis of metal ions inside crevice is widely accepted to be the predominant factor affecting the initiation of crevice corrosion for stainless steels. The accumulation of chloride ions inside crevice is also thought to be of great importance for the initiation of crevice corrosion. 1, 2 In this study, a simultaneous measurement technique for pH and Cl− concentration was applied to the visualization of pH and Cl− distributions inside crevice in the initial stage of crevice corrosion of Type 430 stainless steel. A sensing layer with fluorescent dyes was made on one side of a SiO2 plate using the sol-gel SiO2 coating technique. Quinine sulfate (fluorescent dye) was used to measure Cl− concentration. The excitation wavelength was 350 nm. The emitted light was filtered through a 420-nm long-pass filter, since quinine sulfate has a peak wavelength of 451 nm (blue fluorescence). 1 Tb3+-DPA (dipicolinic acid) complex was used as the fluorescent dye for pH measurements. 2 The excitation wavelength of this dye was 270 nm, and the emitted light was filtered through a 510–550-nm band-pass filter. In this case, green fluorescence was observed. The crevice specimens were prepared from Type 430 stainless steel (Fe-16.5Cr). A crevice (3 mm × 3 mm) was made between the stainless steel and the sensing plate. 1,2 Crevice corrosion tests were carried out in a naturally aerated 0.01 M NaCl at pH 3.0, and the specimen was polarized at 0.0 V (vs. Ag/AgCl, 3.33 M KCl). Before the initiation of crevice corrosion, pH inside the crevice gradually decreased with time. And also, Cl− concentration increased with time. At pH 1.8 and ca. 0.1 M Cl−, crevice corrosion initiated, and a large pH drop and a large Cl− increase were observed.

The early stress response of maize (Zea mays L.) to chloride salinity

AbstractChloride is a micronutrient required for photosynthesis but when applied in the concentration of a macronutrient, it may also promote growth by regulating turgor. However, if chloride accumulates excessively, it can induce toxicity. The aim of this study was to identify physiological dysfunctions in maize (Zea mays L.) that arise in response to excessive chloride ion accumulation. For this, a novel water sensor was employed for the first time allowing the in vivo measurement of water content in the plant by using two near IR‐wavelengths with different absorption of water. This enabled to analyse whether water imbalances occurred. Chloride was given together with calcium as companying counter cation. Results show that most of the tested maize genotypes were able to maintain growth, photosynthesis and normal water content when stressed with concentrations as high as 757.1 mg chloride/kg soil dry matter. Leaf blades accumulated only 8.5 mg chloride/g dry matter, with the most genotypes not even showing salt stress necrosis at the leaves. A comparison between more tolerant and more sensitive genotypes revealed that restriction of chloride root‐to‐shoot translocation is a trait of chloride tolerance.

Blue energy case study and analysis: Attack of chloride ions on chromia passive film on metallic electrode of nanogenerator

The corrosion issue has been considered as the greatest challenge in metallic devices, which will not only degrade the performance but also cause safety concerns. Within the Blue Energy framework, the metallic electrode in nanogenerators will always face the risk of chloride attack through different approaches in the long-term applications within the extreme oceanic conditions. Here in this work, the chloride ion accumulation in the passive film that initiates from the surface adsorption via the surface defects towards the internal migration has been unravelled in our case study and analysis. The underlying chloride ion migration mechanism will be ascribed to the anion Frenkel pair-like mechanism as a defect induced energy transfer process. The molecule dynamic simulations under 300 K also support the evident damage of the passive film induced by the subtle chloride attack. The in-depth understanding of the corrosion process from a microscopic perspective can further assist for diagnosing and remediation of corrosion of the future nanogenerator electrode and other metallic devices.

Hypochlorite Oxidation on RuO2-Based Electrodes: a Combined Electrochemical and In Situ Mass Spectroscopic Study

The hypochlorite oxidation on RuO2 doped with Co, Mg, Ni and Zn was studied by means of voltammetry combined with mass spectroscopy. The hypochlorite oxidation takes place in two distinct steps separated with at least 200 mV. While the first step can be assigned to the direct hypochlorite oxidation, the second one seems to be connected with the oxidation of strongly adsorbed in situ formed hypochlorite. In the oxidation process of hypochlorite, oxygen is the main product but also hydrogen peroxide can be detected. The number of electrons used to produce one molecule of oxygen (z) is less than expected from an electrochemical point of view. This fact, together with an accumulation of chloride ions in solution, indicates that the reaction mechanism of the hypochlorite oxidation involves the formation of radicals that can be regenerated by chemical redox reactions.Graphical ᅟ

Unmasking chloride attack on the passive film of metals

Nanometer-thick passive films on metals usually impart remarkable resistance to general corrosion but are susceptible to localized attack in certain aggressive media, leading to material failure with pronounced adverse economic and safety consequences. Over the past decades, several classic theories have been proposed and accepted, based on hypotheses and theoretical models, and oftentimes, not sufficiently nor directly corroborated by experimental evidence. Here we show experimental results on the structure of the passive film formed on a FeCr15Ni15 single crystal in chloride-free and chloride-containing media. We use aberration-corrected transmission electron microscopy to directly capture the chloride ion accumulation at the metal/film interface, lattice expansion on the metal side, undulations at the interface, and structural inhomogeneity on the film side, most of which had previously been rejected by existing models. This work unmasks, at the atomic scale, the mechanism of chloride-induced passivity breakdown that is known to occur in various metallic materials.

Investigation of computational model for surface chloride concentration of concrete in marine atmosphere zone

Current computational models for the surface chloride concentration of concrete exposed to marine atmosphere zone cannot comprehensively take into account the influence of marine environmental conditions and material parameters of concrete. To overcome this limitation, the transportation process of chloride ions from the marine atmosphere into bulk concrete were explored. Then an improved computational model for the surface chloride concentration of concrete exposed to the marine atmosphere zone was developed on the basis of a large amount of field data. Both environmental conditions and material parameters were considered in the proposed model, including the distance from the sea, wind speed, water-to-binder ratio, binder type and exposure time. The accuracy and applicability of the proposed model were validated by comparing with current computational models and field investigation data. Results show that the proposed model is consistent with the process of transportation and accumulation of chloride ions from sea air into bulk concrete, which overcomes the aforementioned limitation in current models.

Cover Picture: Materials and Corrosion. 1/2017

Cover:The small cross section in the lower right part shows inter‐ and/or transcrystalline cracks in the wall sheet of a 20 years old swimming pool made of stainless steel. The samples tested as well as the visual on‐site inspection revealed pitting at the outer surface of the wall sheet (see large photograph) which initiated stress corrosion cracking. The main cause for the pitting was not an unsuitable material but the environmental conditions at the outer surface enabling accumulation of chloride ions. (Copyright: BAM)