Excess Ions Research Articles

Sb-etching-doping engineering TiSe2@C core–shell with low polarization effect enabling enhanced lithium storage performance

The critical challenge of TiSe2 anode for lithium-ion battery (LIB) lies in the severe polarization due to the accumulation of excessive lithium ions and Li3TiSe2 phase during charge/discharge process, resulting in reduced active sites and sluggish interfacial transport kinetics. To solve the issues, Sb doped TiSe2@C core–shell is synthesized via a combined ion etching-doping route. During the process, the introduced Sb element in MIL-125 triggers a synergistic etching-ion exchanging reaction, leading to a structure change of TiSe2 from bulk to core–shell as well as homogeneous Sb-doping in TiSe2. The unique structure demonstrates nano-crystallization of bulk TiSe2 and the formation of local built-in electric field, providing enough achievable active sites and enhancing interfacial charge/ion transfer kinetics. Benefitting from the synergistic effect of structural engineering and electronic structural engineering, polarization effect is weakened and pseudocapacitance storage ability is improved, leading to the high specific capacity and cycle stability of 502 mAh g−1 after 100 cycles at 0.1 A g−1. Therefore, the synthetic route of Sb doped TiSe2@C core–shell anode can be extended to related nanostructured systems for high performance energy storage device application.

Roles of ATP and SERCA in the Regulation of Calcium Turnover in Unloaded Skeletal Muscles: Current View and Future Directions.

A decrease in skeletal muscle contractile activity or its complete cessation (muscle unloading or disuse) leads to muscle fibers’ atrophy and to alterations in muscle performance. These changes negatively affect the quality of life of people who, for one reason or another, are forced to face a limitation of physical activity. One of the key regulatory events leading to the muscle disuse-induced changes is an impairment of calcium homeostasis, which leads to the excessive accumulation of calcium ions in the sarcoplasm. This review aimed to analyze the triggering mechanisms of calcium homeostasis impairment (including those associated with the accumulation of high-energy phosphates) under various types of muscle unloading. Here we proposed a hypothesis about the regulatory mechanisms of SERCA and IP3 receptors activity during muscle unloading, and about the contribution of these mechanisms to the excessive calcium ion myoplasmic accumulation and gene transcription regulation via excitation–transcription coupling.

Characteristics of cerium doped aluminosilicate glass as simulated radioactive waste forms: Effect on structures and properties

Various cerium doped aluminosilicate glass was prepared by a high-temperature melting method using natural granite material as the only origin of the glass substrate. TG-DSC was used to understand the changes of this aluminosilicate material in the melting process. The structure of the glass was systematically studied by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectra. This type of aluminosilicate material begins to vitrify at about 1000 °C, and its maximum vitrification degree was obtained at 1500 °C. The structure of the glassy waste forms prepared at this temperature is mainly composed of Q3 and Q4 structural units. With the addition of cerium ions, the proportion can even reach 82%. Such good glass integrity makes this type of aluminosilicate glass density and hardness up to 2.89 g cm−3 and 7.80 GPa, respectively. However, the addition of excessive cerium ions destroys the integrity of the network, resulting in that the glass can only carry 17 wt% cerium ions at most. At this point, 55.93% of Ce4+ ions are reduced to Ce3+. In the meantime, cerium ions are evenly distributed in the glass network. This study provides a strategy for the treatment of radioactive waste with similar properties with cerium ions.

Edge termination in vertical GaN diodes: Electric field distribution probed by second harmonic generation

We characterized the electric field distribution of GaN-on-GaN p–n diodes with partially compensated ion-implanted edge termination (ET) using an electric field induced second harmonic generation technique (EFISHG). The distributed electric field from the anode to the outer edge of the ET demonstrates the effectiveness of the ET structure. However, EFISHG also shows that its effectiveness is strongly dependent on the acceptor charge distribution in the ET's partially compensated layer (PC). A generally lower amount of acceptor charge can be inferred from the measured electric field distribution resulting from excessive ion implantation energy or dose during ET fabrication and causing lower than optimal breakdown voltage. Localized field crowding can be observed when the remaining acceptors uncompensated by the implant in the PC layer are nonuniformly distributed around the periphery of the devices. Important information can be obtained from these direct electric field measurements and used for optimizing the device design and fabrication process.

Fluoride removal from aqueous solution via environmentally friendly adsorbent derived from seashell

Nowadays, the presence of excessive ions in water resources is of utmost concern and has attracted increasing attention; therefore, excessive amounts of these ions such as fluoride should be removed from drinking water. Conventional water treatment processes are shown to be incapable of the complete removal of redundant fluoride from aqueous water bodies, whereas adsorption is a promising, effective, cost–benefit, and simple method for this purpose. This study aimed to synthesize effective adsorbents from bivalve shells and evaluate the adsorption function of bivalve shells in removing fluoride from aqueous solutions. In this study, the oyster shell was collected from the Persian Gulf’s seaside and were crushed by manual mortar and blender, and graded with standard sieves with 70 mesh size. The prepared bivalve shell was characterized by SEM and FTIR. To investigate and optimize various variables on fluoride removal percentage a response surface methodology based on central composite design (RSM-CCD) was used. Under optimal conditions (pH: 5.5, adsorbent dose: 0.3 g/L, contact time: 85 min and fluoride concentration: 3 mg/L) the maximum removal efficiency was 97.26%. Results showed that the adsorption equilibrium and kinetic data were matched with the isotherm Langmuir Model (R2 = 0.98) with qmax = 27.31 mg/g and pseudo-second-order reaction (R2 = 0.99). Also, a thermodynamic study exhibited that the adsorption process of fluoride into bivalve shells was an exothermic reaction and could not be a spontaneous adsorption process. Based on the results, the bivalve shell was found as an appropriate adsorbent to remove fluoride from aqueous solutions.

Oxygen nonstoichiometry effects in spin Seebeck insulating Y3−xPrxFe5O12+ δ materials

Yttrium iron garnet (Y3Fe5O12) and its derivatives are ferrimagnetic spin Seebeck insulating materials crucial for the spin transport based phenomena such as the spin Seebeck effect (SSE) and spin Hall magnetoresistance. Structure–property correlation studies of such materials under different conditions are useful for optimizing the relevant constraint in the existed phenomena. The usage of Y3Fe5O12 type materials over the broad range of temperature conditions (27–450 °C) in SSE is under study. We report here the structure–property correlation in spin Seebeck insulating Y3−xPrxFe5O12+δ oxides as a representative material and introduce the additional degrees of freedom in the crystal system relevant to the spin transport based phenomena under high temperature conditions. The natural tendency of having oxygen nonstoichiometry in an iron garnet family of materials strengthens the Fe–O–Fe superexchange interaction, which, in turn, tends to increase the spin voltage correlated magnetic parameters. The analysis of experimental high temperature neutron diffraction data (over 27–450 °C) reveals the oxide ion nonstoichiometry and excess oxide ion transport pathways at moderate temperature 150 °C in the crystal lattices of studied garnet materials. Oxide ion nonstoichiometry, ionic transport, and electron hopping in crystal lattices cause a tremendous variation of electrical conductivity (10−11–10−2 S cm−1) over a moderate change of temperature (27–450 °C). The occurrence of electrical transport in the required thermal gradient over the garnet material in SSE can evoke the additional degrees of freedom in the usage of such materials at high temperatures. The present work provides a new outlook in terms of structure–property correlation for spin transport based materials.

Detecting and Compensating for Excess Ion Micromotion in the Single Ion Optical Frequency Standard

Detecting and Compensating for Excess Ion Micromotion in the Single Ion Optical Frequency Standard

Design and Applications of Liquid Crystal Biophotonic Sensors for Ion Detection

Liquid crystals (LCs) are nanophotonic materials which can interact with light in the molecular scale. While the LCs are widely used in various displays, last decade has witnessed emerging applications of the LCs for nondisplays. Based on the unique stimuli–responsive property and optical property, the applications of the LCs in the field of sensors are widely explored. In addition, ions are widely distributed in nature and bionts, playing critical roles in many physiological activities and ecological cycles. Appropriate amount of ions is beneficial to the human body, while the excess ions can cause irreversible damages. As a result, a variety of LC sensors are proposed to detect the ion concentration in both body fluids and water samples. This article reviews the design principles, applications, and existing problems of the LC ion sensors. The geometries, alignments, and optical signals of the sensors, which can guide the design of the devices, are first discussed. Afterward, two types of LC ion sensors aiming at detecting metal ions and nonmetallic ions, respectively, are illustrated. Finally, the current challenges and potential development directions of the LC ion sensors are introduced briefly.

Physio-anatomical modifications and elemental allocation pattern in Acanthus ilicifolius L. subjected to zinc stress.

Physio-anatomical modifications and elemental distribution pattern in Acanthus ilicifolius subjected to Zn stress were analysed in this study. Survival of A. ilicifolius plants under a high concentration of ZnSO4 was compensated by the reduction in the photosynthetic efficacy. Micro and macro-elemental distribution pattern in the root tissues was significantly influenced by heavy metal exposure. Tolerance towards the excess toxic metal ions in the tissue of A. ilicifolius was aided by the modified anatomical features. Moreover, the increased deposition of Zn around the central vasculature of the root confirms the complexation of Zn2+ in the xylem vessels. Metal induced molecular level changes of root and leaf samples indicate the presence of OH, NH2, and CH3 deformation as well as C-O-H and C-O-C stretch. A prominent band corresponding to CH3 deformation, pointing hemicellulose fortification, occurs in the cell walls of the xylem, aiding in Zn localization. The phytostabilisation potential of A. ilicifolius is dependent on the coordinated responses which endow with phenotypic plasticity necessary to cope with Zn toxicity.

The impact of a magnetic ion on the thermoelectric properties of copper-rich quaternary selenides

A series of copper-based p-type chalcogenide semiconductors, Cu2+x BGe1−x Se4 (B = Zn, Fe; 0 ⩽ x ⩽ 0.15), was prepared by high-temperature methods, to explore the impact of replacement of the closed-shell ion, Zn2+, with the magnetically active, Fe2+ cation. Powder x-ray diffraction in conjunction with Rietveld refinement reveals that zinc-containing materials are described in the kesterite-type structure (space group: ) and contain trace amounts of secondary phases, whereas in the iron analogues, described in the stannite-type structure (space group: I ), single-phase behaviour persists to x = 0.1. Excess copper ions lead to the formation of holes and the electrical resistivity of both series is reduced from that of the stoichiometric end members. In the case of the iron-containing materials, this is shown to be due to an increase in the hole mobility, µ. This decrease in resistivity offsets the observed reduction in Seebeck coefficient and both series exhibit an improvement in thermoelectric performance. The lower electrical resistivity of the iron-containing materials, leads to higher figures-of-merit, compared to those of the zinc-containing materials at the same level of copper excess. The maximum figure-of-merit, ZT = 0.3 is attained for Cu2.075FeGe0.925Se4 at the comparatively low temperature of 575 K. This is an increase of ca. 62% from that of the end member phase and ca. 67% higher than that of the zinc analogue at the same level of substitution.

Structure and dissolution behavior of boron-containing calcium phosphate invert glasses

Boron improves bone growth and maintenance by stimulating osteoblast and osteoclast activity. However, excess boron ions inhibit cellular activity. Therefore, the use of boron in biomaterials requires to control the ion-releasing behavior. Calcium phosphate invert glasses (PIGs) exhibit excellent chemical durability, and their ion-releasing behavior can be controlled by its structure. In this work, B2O3 was substituted for TiO2 in CaO-P2O5-TiO2 invert glasses (PIG-Bs), and the structures and dissolution behaviors were evaluated. B2O3 in PIG-Bs takes the form of BO4 tetrahedra and preferentially bonds with the terminal pyrophosphate to form P–O–B bonds. The degree of glassification and chemical durability of PIG-Bs decreased as the B2O3 content increased because the P–O–B bonds were weaker than the P–O–Ti bonds. Borate ions release amount of PIG-Bs were indicated lower than threshold concentration for negative effect on cells, so PIG-Bs are expected to improve cellular activity without an inhibitory effect.

Comparative genetic, biochemical and physiological analysis of sodium and chlorine in wheat.

Plant with a great diversity shows several responses towards the biotic and abiotic stresses. Among these abiotic stresses, salinity is the main damaging factor as it reduces the yield of wheat plant with moderate salt tolerance. For its survival, plant undergoes through some genetic, biochemical and physiological changes to tackle the stress. This review mainly describes the conditions where various ions present in the soil, especially sodium and chlorine, enter into the plant and the genes or proteins involved with survival mechanism against the damage in plants. Salt stress causes alteration in enzymatic activity and Photosynthesis, oxidative stress, damage of cellular structure and components and ionic imbalance. Ion toxicity stress occur due to accumulation of excessive sodium ion and chloride ion. Transcriptional factors TaPIMP, TaSRG and TaMYBsdu 1 play key role in gene expression mechanism to overcome the stress. High affinity potassium transporter gene family is responsible for salt tolerance in wheat plant. HKT1;4 and HKT1;5 genes are responsible for Na exclusion in Triticum monococcum. Forty QTLs were found with the marker assisted selection in bread wheat for salinity tolerance and some morphological traits, 5 QTLs were related to sodium ion exclusion. In bread wheat, salt stress tolerance mechanism is mainly an exclusion of Na+ ions but also include K+ ion concentration. The salinity tolerant germplasm MW#293 provides an opportunity for the development of future salinity tolerant bread wheat.

Nanoantidote for repression of acidosis pH promoting COVID-19 infection.

Acidosis, such as respiratory acidosis and metabolic acidosis, can be induced by coronavirus disease 2019 (COVID‐19) infection and is associated with increased mortality in critically ill COVID‐19 patients. It remains unclear whether acidosis further promotes SARS‐CoV‐2 infection in patients, making virus removal difficult. For antacid therapy, sodium bicarbonate poses great risks caused by sodium overload, bicarbonate side effects, and hypocalcemia. Therefore, new antacid antidote is urgently needed. Our study showed that an acidosis‐related pH of 6.8 increases SARS‐CoV‐2 receptor angiotensin‐converting enzyme 2 (ACE2) expression on the cell membrane by regulating intracellular microfilament polymerization, promoting SARS‐CoV‐2 pseudovirus infection. Based on this, we synthesized polyglutamic acid‐PEG materials, used complexation of calcium ions and carboxyl groups to form the core, and adopted biomineralization methods to form a calcium carbonate nanoparticles (CaCO3‐NPs) nanoantidote to neutralize excess hydrogen ions (H+), and restored the pH from 6.8 to approximately 7.4 (normal blood pH). CaCO3‐NPs effectively prevented the heightened SARS‐CoV‐2 infection efficiency due to pH 6.8. Our study reveals that acidosis‐related pH promotes SARS‐CoV‐2 infection, which suggests the existence of a positive feedback loop in which SARS‐CoV‐2 infection‐induced acidosis enhances SARS‐CoV‐2 infection. Therefore, antacid therapy for acidosis COVID‐19 patients is necessary. CaCO3‐NPs may become an effective antacid nanoantidote superior to sodium bicarbonate.

Manganese Homeostasis in Bacteria: Interaction of the Small Protein MntS and Manganese Exporter MntP in E. coli

Manganese (Mn) serves as a vital cofactor for bacterial survival, protecting bacteria from reactive oxygen species, radiation, and acidic environments. Bacterial metal ion regulation is associated with pathogenicity, as many virulent strains of bacteria upregulate their ability to obtain metal ions from host species. However, excess metal ions quickly become toxic for most bacteria, resulting in tightly regulated cytoplasmic metal ion concentrations. To better understand regulation of metal levels, our research has focused on the interactions of proteins responsible for Mn homeostasis in Escherichia coli (E. coli), specifically small protein interactions. Small proteins of less than 50 amino acids in length are an emerging group of understudied proteins, yet those that have been studied appear to have important regulatory roles. This research has focused on the small protein called MntS, just 42 amino acids long, which is regulated by the manganese activated transcription factor MntR. In E. coli, MntR represses the production of MntS as well as MntH, a manganese importer, and activates the synthesis of MntP, a manganese exporter. Interestingly, when MntS and MntP are expressed at the same time in the presence of high Mn concentrations, E. coli becomes sensitive to high levels of Mn, suggesting that MntS could interfere with the ability of MntP to export Mn. Indeed, using two‐hybrid assays and co‐purifications we have demonstrated an interaction between MntS and MntP. Additionally, while searching for MntS homologs, we discovered similarity between MntS and the signal peptide (SP) of certain SitA proteins. SitA is a periplasmic protein responsible for cation import, typically Mn. While E. colilacks a SitA protein completely, in the species with the SPs most similar to MntS, the sitAgene is encoded next to mntR. This suggested that the SPs might have similar activity as MntS. We have demonstrated that they produce similar phenotypes in both Mn sensitivity and two‐hybrid assays, suggesting both an evolutionary relationship and a necessary regulatory function. These results provide deeper insight into E. coli’s metal ion regulation, which in the long‐run could allow better treatment of bacterial infections by targeting metal ion regulators.

Applying EDTA in Chelating Excess Metal Ions to Improve Downstream DNA Recovery from Mine Tailings for Long-Read Amplicon Sequencing of Acidophilic Fungi Communities.

The hostile environment of mine tailings contains unique microbial life capable of bioleaching. The metagenomic analysis of such an environment provides an in-depth understanding of the microbial life and its potential, especially in biomining operations. However, DNA recovery from samples collected in those environments is challenging due to the presence of metal ions that interfere with the DNA analysis. A varied concentration of EDTA (4–13 µg/µL) to chelate the metal ions of enriched tailing samples prior to DNA extraction was performed. The results show that 9 µg/µL of EDTA was effective in most samples. However, the increasing concentration of EDTA negatively affected the DNA recovery. The sequencing of the successfully extracted DNA revealed a diverse range of fungal genera, some of which have not been previously reported in tailing or bioleaching applications. The dominant genera include Fodinomyces, Penicillium, Recurvomuces, Trichoderma, and Xenoacremonium; their traits were determined using the FungalTraits database. This study demonstrates the need to include a preliminary metal-chelating step using EDTA before DNA extractions for samples collected from metal-rich environments. It further showed the need for optimization but provided a benchmark range, particularly for tailings. However, we caution that a further EDTA removal step from the extracted DNA should be included to avoid its interferences in downstream applications.

Inhibition of Hydrogen Evolution by a Bifunctional Membrane between Anode and Electrolyte of Aluminum-Air Battery.

The hydrogen evolution reaction of the anode is a severe barrier that limits the further commercial application of Al–air batteries. Therefore, this study introduces a bifunctional membrane for the inhibition of hydrogen evolution in Al–air batteries. The reference to Al2O3@PAN as “bifunctional” means that it has both hydrophobic and anti-corrosion functions. Al2O3 can effectively inhibit the migration of hydroxide ions, and PAN is an excellent hydrophobic material. The bifunctional membrane is placed between the aluminum anode and the electrolyte, which can prevent the invasion of excess water and hydroxide ions, thereby inhibiting the hydrogen evolution corrosion of the anode. Electrochemical tests have confirmed that the corrosion inhibition rate of a bifunctional membrane containing 1.82 wt. % Al2O3@PAN is as high as 89.24%. The specific capacity of Al–air batteries containing this membrane can reach 1950 mAh/g, and the utilization rate of the aluminum anode has reached 61.2%, which is helpful in reducing the waste of aluminum resources. The results prove that the bifunctional membrane has excellent anti-corrosion properties. Bifunctional membranes can also be used to prevent the corrosion of metals in other fields.

Effect of Li nonstoichiometry and TiO2 addition on the microwave dielectric properties of Li3PO4 ceramics

Li3PO4 ceramic is a promising microwave ceramic material with low dielectric constant. The effect of Li nonstoichiometry on phase compositions, microstructures, and microwave dielectric characteristics of Li3PO4 ceramics, on the other hand, has been examined infrequently. Therefore, in the first part of this study, the stoichiometry and Li nonstoichiometry compositions based on Li3+xPO4(x = 0, 0.03, 0.06, 0.09, 0.12 and 0.15) were prepared by conventional solid-phase method. The results show that a few nonstoichiometric lithium ions enter the lattice of Li3+xPO4. Compared with the chemical content of Li3PO4, the sintering characteristics, relative dielectric constants and quality factors of Li3+xPO4 ceramics can be improved by slightly excessive Li ions, while the properties of Li3PO4 ceramics can be deteriorated by excessive Li ions. Li3.12PO4 ceramics sintered at 975 °C for 2 h have good dielectric properties (εr = 5.89, Q×f = 44,000 GHz, τf = −206 ppm/°C). In order to improve its large negative temperature coefficient of resonant frequency, in the following study, rutile nano TiO2 particles were added as τf compensator. Adding TiO2 powders not only effectively improve the temperature stabilities of the multiphase ceramics, but also make the grain growth more uniform. With the increase of TiO2 content from 0.40 to 0.60, τf increases from −73.5 ppm/°C to +42.3 ppm/°C. The best dielectric property of 0.45Li3.12PO4-0.55TiO2 composite ceramic is εr = 13.29, Q×f = 40,700 GHz, τf = +8.8 ppm/°C.

Temperature-Dependent Optical Properties of Perovskite Quantum Dots with Mixed-A-Cations.

In this work, metal halide perovskite quantum dots (QDs) with Formamidinium (FA) and Cs mixed cations were fabricated using a solution-processed method at room temperature. By controlling Cs doping ratios in a precursor, the optical properties of mixed-cation perovskite QDs were systematically studied. With the increase in Cs ion doping, the photoluminescence (PL) spectra of perovskite QDs were blueshifted, which was mainly due to the smaller radius of Cs ions than those of FA. Temperature-dependent PL spectra were conducted on mixed-cation perovskite QDs. As the temperature gradually increased from 4 K to 300 K, PL peaks were blue shifted, and full-width at half maximum (FWHM) was widened, which was directly related to lattice thermal expansion and the carrier-photon coupling effect under temperature variation. At the same time, excess Cs ion doping had a prominent influence on optical properties at low temperatures, which was mainly due to the introduction of detrimental defects in perovskite crystals. Therefore, it is particularly important to control doping concentration in the preparation of high-quality perovskite QDs and efficient photoelectric devices.

Conjugated Polyelectrolyte‐Based Complex Fluids as Aqueous Exciton Transport Networks

The ability to assemble artificial systems that mimic aspects of natural light-harvesting functions is fascinating and attractive for materials design. Given the complexity of such a system, a simple design pathway is desirable. Here, we argue that associative phase separation of oppositely charged conjugated polyelectrolytes (CPEs) can provide such a path in an environmentally benign medium: water. We find that complexation between an exciton–donor and acceptor CPE leads to formation of a complex fluid. We interrogate exciton transfer from the donor to the acceptor CPE within the complex fluid and find that transfer is highly efficient. We also find that excess molecular ions can tune the modulus of the inter-CPE complex fluid. Even at high ion concentrations, CPEs remain complexed with significantly delocalized electronic wavefunctions. Our work lays the rational foundation for complex, tunable aqueous light-harvesting systems via the intrinsic thermodynamics of associative phase separation.

Conjugated Polyelectrolyte-Based Complex Fluids as Aqueous Exciton Transport Networks.

The ability to assemble artificial systems that mimic aspects of natural light-harvesting functions is fascinating and attractive for materials design. Given the complexity of such a system, a simple design pathway is desirable. Here, we argue that associative phase separation of oppositely charged conjugated polyelectrolytes (CPEs) can provide such a path in an environmentally benign medium: water. We find that complexation between an exciton-donor and acceptor CPE leads to formation of a complex fluid. We interrogate exciton transfer from the donor to the acceptor CPE within the complex fluid and find that transfer is highly efficient. We also find that excess molecular ions can tune the modulus of the inter-CPE complex fluid. Even at high ion concentrations, CPEs remain complexed with significantly delocalized electronic wavefunctions. Our work lays the rational foundation for complex, tunable aqueous light-harvesting systems via the intrinsic thermodynamics of associative phase separation.