Cation Concentration Research Articles

The novel strategy of ion-adsorbed minerals leaching based on high abundance yttrium for resources, environment and efficiency

Yttrium (Y) is the most abundant RE element in ion-adsorbed RE minerals. To realize the balanced and sustainable application of RE resources, some Y salts (YCl3, Y2(SO4)3 and Y(NO3)3) were used instead of (NH4)2SO4 and MgSO4 as leachants to recover RE from ion-adsorbed RE minerals in this study. During the soak leaching process, when the cation concentration of the leachant is 0.05 mol/L, the leaching efficiency decreases from 59% to 37% in the order of Y3+>Mg2+>NH4+. The leaching rate increases with the increase of the concentration of the leachant. In the column leaching, at the concentration of 0.01 mol/L leachant, the final leaching rate of YCl3 for non-Y RE is 55.63%, while the leaching rate of Mg2SO4 is only 30.78%. The effects of concentration and pH value of the leachant on the column leaching were studied. The optimum conditions were determined as follows: the solid-liquid ratio was 1:1, the pH value was 4, the concentration of YCl3 was 0.03 mol/L, and the maximum leaching efficiency of non-Y RE was 100%. The absolute zeta potential of tailings after YCl3 leaching is located in a strong agglomeration area, which is helpful to avoid landslides in goaf areas. This study shows that YCl3 has excellent potential to leach RE instead of (NH4)2SO4. It provides a new choice to solve the environmental problems from ammonia-nitrogen pollution caused by industrial (NH4)2SO4 leaching. The leaching strategy of Y is helpful to protect RE resources, reduce environmental pollution and improve RE separation efficiency.

Adsorption behavior of triclosan on microplastics and their combined acute toxicity to D. magna

Microplastics (MP) have been recently identified as emerging water contaminants in worldwide. Owing to its physicochemical properties, MP have been considered as a vector of other micropollutants and may affect their fate and ecological toxicity in the water environment. In this study, triclosan (TCS), which is a widely-used bactericide, and three frequently found types of MP (PS-MP, PE-MP, and PP-MP) were investigated. The adsorption behavior of TCS on MP was investigated by the effect of reaction time, initial concentration of TCS, and other water chemistry factors. Elovich model and Temkin model are the most fitted well with kinetics and adsorption isotherms, respectively. The maximum TCS adsorption capacities were calculated for PS-MP (9.36 mg/g), PP-MP (8.23 mg/g), and PE-MP (6.47 mg/g). PS-MP had higher affinity to TCS owing to hydrophobic and π-π interaction. The TCS adsorption on PS-MP was inhibited by decreasing concentrations of cations, and increasing concentration of anion, pH, and NOM concentration. At pH 10, only 0.22 mg/g of adsorption capacity was obtained because of the isoelectric point (3.75) of PS-MP and pKa (7.9) of TCS. And almost no TCS adsorption occurred at NOM concentration of 11.8 mg/L. Only PS-MP had no acute toxic effect on D. magna, whereas TCS showed acute toxicity (EC50,24h of TCS = 0.36 ± 0.4 mg/L). Although survival rate increased when TCS with PS-MP due to lower the TCS concentration in solution via adsorption, PS-MP was observed in intestine and body surface of D. magna. Our findings can contribute to understanding the combined potential effects of MP fragment and TCS to aquatic biota.

Temporal changes in soil chemical compositions in acidified mountain forest soils of Czech Republic

The study aimed to investigate the temporal changes of pH, sorption complex, and structure of soil organic matter through the forest soil profile under beech and spruce forests located in Jizera mountains (Czech Republic) and affected by natural and anthropogenic acidification. Soil samples were collected in four different years (2008, 2013, 2015, and 2020) in each horizon: fermented horizons (F), humified horizons (H), organo-mineral horizons (A), and subsurface mineral horizons (B) (cambic or spodic). The cation exchange capacity (CEC), base saturation (BS), exchangeable element contents, pH, and soil organic carbon content (SOC) were determined. The infrared soil spectra were used to calculate indices of potential wettability, aromaticity, and decomposition. Our results showed that most nutrients and aliphatic compounds were retained in the uppermost soil layers. The aromaticity of organic matter increased with depth, while polysaccharides, regarding the decomposition compound, disappeared through the soil horizons. In a long-term observation, SOC content had constantly increased under beech, while spruce remained stable in the organic horizons. Exchangeable element contents increased in each horizon, except for Al and Fe; their content quickly decreased in F horizons and slowly decreased in H horizon under both forest tree species, while the deeper horizons remained constant, but increased in A horizon under spruce. Continuously increasing base cations concentrations in sorption complex of both forest tree species during the study period revealed the effect of forest stand types on acid deposition reduction and mitigation. The temporal changes in CEC, BS, SOC, and soil wettability are more intensive in beech than in spruce forest floor.

Hydro-chemical Characteristics of Melt Water Draining from Glaciers of Rongdo Basin, Shyok Valley, Ladakh

Abstract Physico-chemical parameters of meltwater of 20 water samples from glaciers of Rongdo basin, Shyok valley are presented here. The concentration of cations and anions of the two valleys were found in the order Ca>Mg>Na>K and HCO3>SO4>Cl>NO3 respectively. Significant altitudinal variation was found in major ions as indicated by the increase of TDS of glacial melt and stream water samples downstream. Gibbs plot shows chemical weathering of the rock forming minerals as the main cause for contributing ions to the melt water. The dominant order of hydrogeochemical water types identified is Ca-HCO3, is due to the water rock interaction which leads to the easy dissolution of carbonate and silicate minerals. However, few glacial melt and stream water have the influence of precipitation and meltwater runoff on chemistry. The hot spring falls in Na-HCO3 type, a typical of deeper groundwater influenced by ion exchange processes. Scatter plots of HCO3+SO4 vs. Ca/Na Plot and Ca/Na vs. HCO3/Na clearly indicates that the weathering of carbonate and silicate play a dominant role on groundwater chemistry. Two chloro-alkaline indices indicate reverse exchange reaction between Na+, K+, Mg2+and Ca2+. The physical parameters and major ions are within the permissible concentrations as per WHO and BIS indicating water is good for drinking and domestic purposes. The groundwater is suitable for irrigation as per the quality parameters and plots including EC, sodium percent (Na%) and sodium adsorption ratio (SAR).

Organic Matter Structural Composition of Vascular Epiphytic Suspended Soils of South Vietnam

The biosphere organic matter is stored in nature in various forms. Most of it is associated with classical terrestrial organo-mineral soils. The carbon of woody plant biomass is counted separately from soil as carbon of the standing biomass. Nevertheless, humification as a universal process already begins in plant residues before they reach the surface of the classical tropical mineral soil. Moreover, in tropical humid-forest ecosystems, most of the organic matter does not reach the soil surface at all and accumulates in the state of suspended soils. The data obtained in this study characterize, for the first time, the component and structural composition of the organic matter of plant residues of suspended soils, as well as the products of their transformation—humic substances formed in suspended soils. With the use of micro morphological methods, it was shown that humification appears in merged areas of organic remnants. There were statistically significant differences in the elemental composition of humic acids and initial organic material for all elements—C, H, O and N. It has been shown that the aliphatic part dominates (75–93%) in the initial organic materials of suspended soils, whereas the humic substances are characterized by a relatively increased fraction of aromatic fragments (31–42%) in the composition of their molecules, which confirms that humification takes place. Thus, even in the suspended soils, classical humification occurs, and this is not limited by the low content of mineral particles and cations in the suspended soils and the rather acidic reaction of the material. Therefore, the existence of tiering and the formation of the corresponding layers of suspended soils is accompanied by the stabilization and humification of organic matter, which is accompanied by a radical change in its structural and component composition. This process is the “natural biotechnology” of organic matter conservation and stabilization is discussed in article.

Geochemical Signatures of Bara Basin Aquifers, Kordofan State, Sudan

Purpose: In this paper, geochemical investigation has been carried out to study the concentrations of major cations; Sodium (Na+), Potassium (K+), Magnesium (Mg2+), and Calcium (Ca2+), and major anions; Chloride (Cl-), Bicarbonate (HCO3-), Nitrate (NO3-) and Sulphate (SO42-), other parameters such as (pH), Electric conductivity and T.D.S were also studied in all water samples taken from wells in Bara basin.
 Methodology: Forty five (45) water samples have been collected from wells. Lab works were done at Groundwater and Wadis Directorate (GWD), Khartoum State according to Sudanese Standards and Metrology Organization, (2002), to study the major cations and major anions.
 Findings: The results revealed that the average value of pH was (7.9) E.C values were (843.4 μS/cm) and T.D.S values were (59 mg/l). The average concentrations of the major cations obtained were; Na+ (126.3), K+ (5.22), Mg2+ (28.30), Ca2+(66.41) and the major anions (mg/l) were; Cl- (159.00), HCO3- (165.30), NO3- (156.70) and SO42- (164.70). The (Na/Cl) ratio is (2.47) is also high which reflects the abundance of (Na+) ions relative to the Chloride (Cl-) ions which confirmed the light-salty nature of groundwater. Geochemical mass balance calculations indicate that upper aquifer is mainly affected by the dissolution and dolomitization processes of major anions.
 Unique Contribution to Theory, Policy and Practice: This process is highly developed in the central west part of the basin due to the abundance of Sulphate (SO42-), Bicarbonate (HCO3-), Magnesium (Mg2+), and Calcium (Ca2+) ions. High values of E.C, T.D.S, Ca2+, and SO42- are mainly presents as a saline water resource in some villages. Two types of water are classified here these are : i). Na-HCO3 type and ii). Ca- Cl -SO4 type. The study concluded that water samples from Almakser, Hamdan-2, Um-Zeeraga-2, and Al-Zareeba-2 villages have very high concentrations of E.C, T.D.S Ca2-, Cl-, NO3- and SO42-, which may suggest that water samples are not fit for human consumption, according to guidelins by W.H.O (1984). This paper recommends further study on water quality.

Some molecular-sieve peculiarities of natural zeolite of Georgia

Ion exchange property of fibrous zeolite scolecite of Georgian origin has been studied against mono (Li, Na, NH4, K Cs and Rb), divalent (Sr, Ba Ca, Mg) and transition (Cd, Cu, Mn, Zn, Co and Ni) metal cations. Selectivity series of the above cations for scolecite have been compiled. The structure of scolecite, charge and sizeof the cations (both in hydrated and dehydrated state) and cation concentration in the solution (0.1N, 0.3N, 0.5N 1.0N and 1.5N) greatly influence on the ion-exchange property and selectivity order of scolecite. Dynamic Exchange Capacity (DEC) values for the studied cations on scolecite have been calculated. Kinetics of ion exchange in dynamic conditions for the above cations has been studied. Analysis of the obtained data shows that the external diffusion processes have influence on the establishment of equilibrium between the ions on the surface and in the micro porous structure of scolesite. The time of dynamic exchange equilibrium is directly proportional to the cation radios.

Machine learning assisted modeling of interfacial tension in the system N2/Brine

The CO2 rising in the atmosphere causes serious greenhouse effects on severe and sustainable global warming. Carbon capture is one of the most viable approaches accepted to achieve sustainable development goals. On the other hand, flue gases contain large amounts of CO2 and N2. For the purpose of CO2 sequestration in depleted reservoirs or saline aquifers, a deep understanding about the interaction between these components with brine is vital. Among the most important parameters, which can be investigated for such applications, is interfacial tension (IFT) in these systems. In the current study, we have measured IFT between N2 and different brines including monovalent and divalent ions at various temperatures and pressures at different salinity ranges. Various brines containing different salts such as NaCl, Na2SO4, KCl, MgCl2, and CaCl2 were synthesized in the range of salinity between 10000 ppm and 50000 ppm. The temperature and pressure ranges of our study were 30–70 °C, and 0.1–30 Mpa, respectively. IFT700 (Vinci, France) instrument was used for our experiments. The obtained experimental data were then analyzed using different machine learning algorithms. The prediction of IFT as a response variable (in the range of 31.39–74 mN/m) with independent variables including temperature (K), pressure (Mpa), and molar concentrations of different anions and cations (M) was carried out using adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) with feed-forward architecture models which was trained using particle swarm optimization (PSO) algorithm as an evolutionary algorithm. Based on the present study results, the IFT was predicted accurately by ANFIS + PSO and ANN + PSO endorsed with good performance parameters. The coefficient of determination (R2), mean squared error (MSE), mean absolute error (MAE), and average absolute relative deviation (AARD%) were calculated to assess the accuracy of the models. Both models showed very good performance, with R2 coefficient 0.9898 and 0.9938 for test data of ANN + PSO and ANFIS + PSO, respectively. As it can be seen from the results, ANFIS and ANN methods were very successful for predicting the behavior of the complex systems studied in this work, while the ANFIS + PSO model had a better predictive power. It can be explained by the fact that ANFIS is a modeling technique that combines the power of artificial neural network with fuzzy logic theory techniques. It can apply FIS to define hidden layers and improve its predictive ability.

Phase Transition Kinetics of MAPbI3 for Tetragonal-to-Orthorhombic Evolution.

Despite the commonly observed phase-instability-induced photovoltaic degradation of MAPbI3, the phase transition kinetics at the atomic level remains elusive. Herein, by developing a stepwise NEB method, we clarify a nonsynergistic minimum-energy pathway for the tetragonal-to-orthorhombic phase transition. It is kinetically driven by the tilting of PbI6 4- that induces a spontaneous small rotation of adjoining MA+ and ends with stepwise ∼110° reorientations of two nonadjacent MA+ enabled by the cavity expansion. Compared to the common concerted mechanism, this process gives a low barrier of 0.08 eV/unit, demonstrating the easiness of the transition at extremely low temperatures and the importance of rotational entropies in regulating transition at elevated temperatures. With an explicit phase transition mechanism, we explore the structure-induced property response and reveal that introducing even low content of large-sized organic cations could help maintain the quasi-stable low-temperature performance of MAPbI3 solar cells.

Potent, Gut-Restricted Inhibitors of Divalent Metal Transporter 1: Preclinical Efficacy against Iron Overload and Safety Evaluation.

Divalent metal transporter 1 (DMT1) cotransports ferrous iron and protons and is the primary mechanism for uptake of nonheme iron by enterocytes. Inhibitors are potentially useful as therapeutic agents to treat iron overload disorders such as hereditary hemochromatosis or β-thalassemia intermedia, provided that inhibition can be restricted to the duodenum. We used a calcein quench assay to identify human DMT1 inhibitors. Dimeric compounds were made to generate more potent compounds with low systemic exposure. Direct block of DMT1 was confirmed by voltage clamp measurements. The lead compound, XEN602, strongly inhibits dietary nonheme iron uptake in both rats and pigs yet has negligible systemic exposure. Efficacy is maintained for >2 weeks in a rat subchronic dosing assay. Doses that lowered iron content in the spleen and liver by >50% had no effect on the tissue content of other divalent cations except for cobalt. XEN602 represents a powerful pharmacological tool for understanding the physiologic function of DMT1 in the gut. SIGNIFICANCE STATEMENT: This report introduces methodology to develop potent, gut-restricted inhibitors of divalent metal transporter 1 (DMT1) and identifies XEN602 as a suitable compound for in vivo studies. We also report novel animal models to quantify the inhibition of dietary uptake of iron in both rodents and pigs. This research shows that inhibition of DMT1 is a promising means to treat iron overload disorders.

Magnesium and Zinc in Bipolar Disorders

Bipolar disorder ( BD ) is a severe and recurrent mood disorder. The influence of magnesium and zinc on animal behavior is certain and this has been experimentally demonstrated repeatedly. However, some clinical studies have positively correlated the decrease in the concentration of the two cations with a more severe symptomatology of BD, but in other cases no modified values ​​of the concentration of magnesium and zinc were found or no relationship was identified between these concentrations and the clinical manifestations of the disease. This diversity of results has various causes but the most important of these are: problems regarding the diagnosis of BP and the diagnostic criteria used; the phases of the disease in which the cationic concentrations were determined were different; determination of intracellular magnesium was rarely done; the different ages of the patients and different associated diseases influenced the interpretation of the results. In some studies, the administration of some mood modulators (sodium valproate, carbamazepine or quetiapine) in BD type I hospitalized adult patients during the maniacal episode has increased plasma zinc and erythrocyte magnesium concentration . Missing correlations between how long is the evolution of the disease and the levels of these cations. Existing date support the idea that a low level of magnesium and zinc play a role in pathogenesis of BD. The assertion of a definite beneficial role of the association of magnesium and zinc with mood modulators in BD therapy requires more clinical studies.

Combined Utilization of Chinese Milk Vetch, Rice Straw, and Lime Reduces Soil Available Cd and Cd Accumulation in Rice Grains

Cadmium (Cd) pollution poses a growing threat to rice production in acidic paddies. In south China, a common agricultural practice involves the combined utilization of Chinese milk vetch (M) and rice straw (R). However, it is unclear how the addition of lime to these amendments affects Cd bioavailability and accumulation in soil. Control (CK), chemical fertilizer (F), Chinese milk vetch + rice straw + chemical fertilizer (MRF), and Chinese milk vetch + rice straw + chemical fertilizer + lime (MRFL) treatments were applied to develop a kind of green, efficient, and practical amendment for acidic paddies. We conducted a microplot experiment to explore Cd immobilization in paddy soil and the Cd content in rice grains with these treatments. The results showed that compared with F, the rice Cd in the MRF and MRFL treatments were significantly decreased by 51.7% and 65.2% in early rice and 23.0% and 43.3% in late rice, respectively. Both the MRF and MRFL treatments significantly reduced soil available Cd and weak acid-extractable cadmium (Aci-Cd) concentrations and increased soil organic matter (SOM), exchangeable cation concentrations, and pH, which converted Cd into a stable form in soil. In addition, the MRF and MRFL treatments increased soil pH value by reducing soil exchangeable hydrogen ion concentration (E-H). Additionally, recombination of Cd forms was the primary factor in the reduction in available Cd concentration according to partial least squares path modeling (PLS-PM) analysis. The Cd concentration of rice grains was primarily associated with soil available Cd, soil pH value, and SOM. Overall, these results provide useful data and novel insights into reducing rice grain Cd in south China.

Single-Molecule Force Spectroscopy Reveals Cation-π Interactions in Aqueous Media Are Highly Affected by Cation Dehydration.

Cation-π interactions underlie many important processes in biology and materials science. However, experimental investigations of cation-π interactions in aqueous media remain challenging. Here, we studied the cation-π binding strength and mechanism by pulling two hydrophobic polymers with distinct cation binding properties, i.e., poly-pentafluorostyrene and polystyrene, in aqueous media using single-molecule force spectroscopy and nuclear magnetic resonance measurement. We found that the interaction strengths linearly depend on the cation concentrations, following the order of Li^{+}<NH_{4}^{+}<Na^{+}<K^{+}. The binding energies are 0.03-0.23 kJ mol^{-1} M^{-1}. This order is distinct from the strength of cation-π interactions in gas phase and may be caused by the different dehydration ability of the cations. Taken together, our method provides a unique perspective to investigate cation-π interactions under physiologically relevant conditions.

Synthesis of coral-like structures of Pr–Yb co-doped YIG: Structural, optical, magnetic and antimicrobial properties

Coral-like structures of the Y3–xPrxFe5–yYbyO12, (0.00 ≤ x ≤ 0.04), (0.00 ≤ y ≤ 0.02) compound were synthesized using the sol-gel method. Structural investigation certified the YIG cubic crystal structure formation, without any secondary phase. It is shown that, the relatively large ionic radius of the dopant cations results in an expansion of the lattice parameter, variations in the Iona‒O‒Iond angle, Iona‒O, Iond‒O and Ionc‒O bond distances and decrease in the average crystallite size. Fourier transform infrared (FTIR) and Raman measurements are essential to testify the single-phase formation of YIG crystal structure and are observed changes in the stretching and vibrational modes, respectively. The morphological study, energy dispersive spectroscopy (EDS) spectra and textural properties show coral-like structures, peaks associated with Pr3+ and Yb3+ atoms and the effect of dopants on surface area, diameter, and pore volume, respectively. The optical analysis from diffuse reflectance spectra witnessed an increase in the optical gap band, a decrease in Urbach energy and blue shift in the charge transfer, correlated with the expansion of the unit cell due to the dopant's insertion in the YIG structure. A typical ferrimagnetic behavior is exhibited by the Y3–xPrxFe5–yYbyO12 compound. The saturation magnetization (Ms), cubic anisotropy constant (K1) and coercive field (Hc) increase with the Pr3+ cations content, as consequence of their magnetic nature and distribution around of Fe3+ ions due to the coexistence with the Yb3+. Finally, for the first time, antibacterial tests by mean of the direct contact method were performed for YIG co-doped with Pr3+ and Yb3+ and it is shown that, relatively high dosages of Pr3+ cations favored the activity against S. aureus, therefore, a new biological property for YIG doped with rare earths is presented.

Cation-responsive food polysaccharides and their usage in food and pharmaceutical products for improved quality of life

Demand for reduction of complication risks encountered in feeding of thin enteral nutrition including gastroesophageal reflux, dumping, and leakage from gastrostomy has increased in recent aged society, where people with eating difficulty has been increasing. In addition, control of satiety and caloric intake is demanded for long and healthy life. To realize these social demands, texture modification of liquid foods, particularly through semi-solidification (i.e. gelation and thickening) in the stomach, can be expected as a solution not to alter human natural feeding. In the stomach, foods encounter dramatic pH decrease, which can be used as a trigger for semi-solidification of liquid foods, and usage of polysaccharides whose molecular structure changes upon pH and accompanying cation concentration should be a practical option. With this background, this review refers to the basic technologies for the usage of alginate and pectin as cation-responsive polysaccharides in food and pharmaceutical products, followed by comprehensive overview of product development and clinical effects using them. In addition, solution to improve storage stability of the products will be mentioned when these polysaccharides are used. Information provided by this review is expected to facilitate the product development of high-value added and to contribute to improved quality of life for people.

Determination Of Exchangeability Cations (Ec), Texture And C-Organic Content In Mineral Soils and Peat

EC or can be called exchangeable cation is a nutrient cation found in the soil. This is useful for indicating the degree of alkaline saturation, which indicates that the more saturated the soil base, the more fertile the soil will be. This study aims to obtain supporting information to obtain soil conditions that show the quality of the land as a growing medium. The method used for texture analysis on this soil refers to SNI 3423.03:1994 and C-Organic content analysis refers to SNI 4720.13:1998. The cation level test was carried out using NH4OAc solution with a Microwave Plasma Atomic Emission Spectroscopy (MP-AES) instrument. This instrument has a principle, namely atomic emission which is a form of energy produced by an atom when it returns to the ground state (Ground State) of the excited state (Excitation State). The results of this cation level test with analyte concentrations of K, Ca, Na and Mg with sample code SJ2022-01826 successively 0.65; 3,59; 0.82 and 0.94. The amount of cation content in fertile soil is worth at least 6 mg / L in accordance with the provisions of the Chemical Technical Manual.

The Sensory Histidine Kinase CusS of Escherichia coli Senses Periplasmic Copper Ions.

Two-component regulatory systems composed of a membrane-bound sensor/sensory histidine kinase (HK) and a cytoplasmic, DNA-binding response regulator (RR) are often associated with transenvelope efflux systems, which export transition metal cations from the periplasm directly out of the cell. Although much work has been done in this field, more evidence is needed for the hypothesis that the respective two-component regulatory systems are indeed sensing periplasmic ions. If so, a regulatory circuit between the concentration of periplasmic metal cations, sensing of these metals, and control of expression of the genes for transenvelope efflux systems that remove periplasmic cations can be assumed. Escherichia coli possesses only one transenvelope efflux system for metal cations, the Cus system for export of Cu(I) and Ag(I). It is composed of the transenvelope efflux system CusCBA, the periplasmic copper chaperone CusF, and the two-component regulatory system CusS (HK) and CusR (RR). Using phoA- and lacZ-reporter gene fusions, it was verified that an assumed periplasmic part of CusS is located in the periplasm. CusS was more important for copper resistance in E. coli under anaerobic conditions than under aerobic conditions and in complex medium more than in mineral salts medium. Predicted copper-binding sites in the periplasmic part of CusS were identified that, individually, were not essential for copper resistance but were in combination. In summary, evidence was obtained that the two-component regulatory system CusSR that controls expression of cusF and cusCBA does indeed sense periplasmic copper ions. IMPORTANCE Homeostasis of essential-but-toxic transition metal cations such as Zn(II) and Cu(II)/Cu(I) is an important contributor to the fitness of environmental bacteria and pathogenic bacteria during their confrontation with an infected host. Highly efficient removal of threatening concentrations of these metals can be achieved by the combined actions of an inner membrane with a transenvelope efflux system, which removes periplasmic ions after their export from the cytoplasm to this compartment. To understand the resulting metal cation homeostasis in the periplasm, it is important to know if a regulatory circuit exists between periplasmic metal cations, their sensing, and the subsequent control of the expression of the transenvelope efflux system. This publication adds evidence to the hypothesis that two-component regulatory systems in control of the expression of genes for transenvelope efflux systems do indeed sense metal cations in the periplasm.

An Assessment of Groundwater Quality for Drinking Purpose in Tando Adam City of Sindh, Pakistan

The present study is aimed to assess the groundwater quality of Tando Adam city of district Sanghar, Sindh. Total twenty groundwater samples were randomly collected from handpump wells installed on different locations at various depths (50-90ft). The groundwater samples were analyzed for physicochemical and microbiological parameters to determine suitability for drinking purposes. Analytical results showed that most of water samples have elevated contents of Total Dissolved Solids (TDS) exceeding the permissible limit (&lt;1000mg/l) for drinking water. The concentration of cations (Ca+2, Mg+2, Na+, K+) and anions (Cl-, HCO3-, SO4-2) were so high that World Health Organization (WHO) standards seem overcrossing in &gt;80% water samples. Local geology, poor irrigation practices, and anthropogenic activities are responsible for higher ion concentrations in the area. Furthermore, Microbiological contamination was found positive in half of the groundwater samples due to sewage contamination, poor sanitation and dumping of waste near well sites. The groundwater quality of the study area is highly contaminated and not suitable for human consumption but despite being commonly used for drinking purpose.

Exsolution Modeling and Control to Improve the Catalytic Activity of Nanostructured Electrodes.

In situ exsolution for nanoscale electrode design has attracted considerable attention because of its promising activity and high stability. However, fundamental research on the mechanisms underlying particle growth remains insufficient. Herein, cation-diffusion-determined exsolution is presented using an analytical model based on classical nucleation and diffusion. In the designed perovskite system, the exsolution trend for particle growth is consistent with this diffusion model, which strongly depends on the initial cation concentration and reduction conditions. Based on the experimental and theoretical results, a highly Ni-doped anode and an electrochemical switching technique are employed to promote exsolution and overcome growth limitations. The optimal cell exhibits an outstanding maximum power density of 1.7Wcm-2 at 900°C and shows no evident degradation when operating at 800°C for 240h under wet H2 . This study provides crucial insights into the developing and tuning of heterogeneous catalysts for energy-conversion applications.

Lipid peroxidation increases membrane tension, Piezo1 gating, and cation permeability to execute ferroptosis

The ongoing metabolic and microbicidal pathways that support and protect cellular life generate potentially damaging reactive oxygen species (ROS). To counteract damage, cells express peroxidases, which are antioxidant enzymes that catalyze the reduction of oxidized biomolecules. Glutathione peroxidase 4 (GPX4) is the major hydroperoxidase specifically responsible for reducing lipid peroxides; this homeostatic mechanism is essential, and its inhibition causes a unique type of lytic cell death, ferroptosis. The mechanism(s) that lead to cell lysis in ferroptosis, however, are unclear. We report that the lipid peroxides formed during ferroptosis accumulate preferentially at the plasma membrane. Oxidation of surface membrane lipids increased tension on the plasma membrane and led to the activation of Piezo1 and TRP channels. Oxidized membranes thus became permeable to cations, ultimately leading to the gain of cellular Na+ and Ca2+ concomitant with loss of K+. These effects were reduced by deletion of Piezo1 and completely inhibited by blocking cation channel conductance with ruthenium red or 2-aminoethoxydiphenyl borate (2-APB). We also found that the oxidation of lipids depressed the activity of the Na+/K+-ATPase, exacerbating the dissipation of monovalent cation gradients. Preventing the changes in cation content attenuated ferroptosis. Altogether, our study establishes that increased membrane permeability to cations is a critical step in the execution of ferroptosis and identifies Piezo1, TRP channels, and the Na+/K+-ATPase as targets/effectors of this type of cell death.