Abundant Ions Research Articles

A novel pyrazole-pyrazoline fluorescent probe for the detection of Cu2+ and Fe3+ in living cells

Copper ions and iron ions are abundant metal ions in nature, and are also essential trace elements in the human body, playing a crucial role in various physiological activities. However, the detection of copper and iron ions also poses significant challenges. This article reports the synthesis of a novel fluorescent probe X2 based on the pyrazole structure, which exhibits unique optoelectronic properties, strong biological activity, good selectivity, excellent detection limit, high sensitivity, and its structure was characterized by 1H NMR, 13C NMR, and HR-ESI-MS. The obtained probe exhibits AIE characteristics, and its mechanism was analyzed through infrared spectrum and theoretical calculations. Finally, through cytotoxicity and cell imaging experiments, it was demonstrated that the probe has low toxicity and can be used in the field of biology. This article provides a new approach for detecting copper and iron ions using fluorescent probes with pyrazole structures.

Phosphorous Incorporated PtNi Networks with Synergistic Directional Electron Transfer for Efficient and Durable Seawater Hydrogen Production

AbstractThe abundant chloride ions in seawater, which poison and corrode electrode materials, are the main reason for the low performance of Pt‐based catalysts toward hydrogen evolution reaction (HER) in seawater. Coupling Pt with oxophilic transition metals can enhance the activity of Pt‐based electrocatalysts, but their long‐term stability is still unsatisfactory. Herein, a small number of phosphorous atoms (from 1.2 to 5.9 at%) are precisely incorporated into PtNi networks (P‐PtNi networks) via a facile aqueous reduction strategy at room temperature. Experimental measurements and theoretical calculations prove that P incorporation leads to a synergistic directional electron transfer from P and Ni to Pt, resulting in improved water dissociation kinetics, enhanced Cl– resistance and facilitated hydrogen adsorption. Consequently, P‐PtNi networks exhibit outstanding HER activities with a lower overpotential of 37 mV at 10 mA cm−2 and an 8.5‐fold higher mass activity at –0.07 V compared to commercial Pt/C and only slightly lowered potential after 120 h of testing in alkaline simulated seawater. Furthermore, P‐PtNi networks show an ultrahigh solar‐to‐hydrogen efficiency of 15.2% for solar cell‐driven hydrogen production from seawater. This work sheds new lights on the design of high‐performance Pt‐based nanomaterials toward practical applications of seawater hydrogen production.

Hydrogen underground storage potential in sandstone formation: A thorough study utilizing surface complexation modelling

This research focuses on the geochemical aspects of hydrogen underground storage, with particular emphasis on surface complexation modelling and its impact on surface potential and surface charge. The primary objective is to develop the first comprehensive surface complexation model specifically tailored for sandstone rocks, emphasizing key minerals such as quartz, kaolinite, and calcite, which are suitable for hydrogen underground storage applications. This model is intended to serve as a benchmark for more research in this field, providing a solid foundation for investigating and improving predictions related to wettability alteration. Additionally, the model has been integrated with hydrogen solubility to accurately capture changes in surface charge. The study identified six brine compositions with various minerals to examine the effect of monovalent and divalent ions. The results showed an increase in solubility with an overall reduction in salinity, and a decrease in divalent ions. The homogeneous surface complexation model demonstrated a neutral surface potential, attributed to an increased mole fraction of positively charged >SiOH+and a decreased in negatively charged >SiO-. Similar trends were observed in kaolinite and calcite minerals. The influence of pH was also explored, revealing a significant impact on the homogeneous quartz case, where an increase in pH shifted the surface potential from neutral to more negative. The heterogeneous cases exhibited less negative behavior as the quartz content increased per case, mainly due the increasing presence of positively charged species such as >SiOH+ and >AlOH+, and the reduction of the negatively charged >AlO-. Increasing the salinity of the solution resulted in less negative surface potential, attributed to the abundance of positive divalent and monovalent ions boosted by increasing salinity, thus the formation of positive surface complexes.

Calcium ion-triggered liquid-liquid phase separation of silk fibroin and spinning through acidification and shear stress

Many studies try to comprehend and replicate the natural silk spinning process due to its energy-efficient and eco-friendly process. In contrast to spider silk, the mechanisms of how silkworm silk fibroin (SF) undergoes liquid–liquid phase separation (LLPS) concerning the various environmental factors in the silk glands or how the SF coacervates transform into fibers remain unexplored. Here, we show that calcium ions, among the most abundant metal ions inside the silk glands, induce LLPS of SF under macromolecular crowded conditions by increasing both hydrophobic and electrostatic interactions between SF. Furthermore, SF coacervates assemble and further develop into fibrils under acidification and shear force. Finally, we prepare SF fiber using a pultrusion-based dry spinning, mirroring the natural silk spinning system. Unlike previous artificial spinning methods requiring concentrated solutions or harsh solvents, our process uses a less concentrated aqueous SF solution and minimal shear force, offering a biomimetic approach to fiber production.

High-Performance Chemigenetic Potassium Ion Indicator.

Potassium ion (K+) is the most abundant metal ion in cells and plays an indispensable role in practically all biological systems. Although there have been reports of both synthetic and genetically encoded fluorescent K+ indicators, there remains a need for an indicator that is genetically targetable, has high specificity for K+ versus Na+, and has a high fluorescent response in the red to far-red wavelength range. Here, we introduce a series of chemigenetic K+ indicators, designated as the HaloKbp1 series, based on the bacterial K+-binding protein (Kbp) inserted into HaloTag7 self-labeled with environmentally sensitive rhodamine derivatives. This series of high-performance indicators features high brightness in the red to far-red region, large intensiometric fluorescence changes, and a range of Kd values. We demonstrate that they are suitable for the detection of physiologically relevant K+ concentration changes such as those that result from the Ca2+-dependent activation of the BK potassium channel.

Covalent Organic Frameworks with Constrained Palladium Nanoclusters Lock the Enol-Keto Tautomerism Enhancing Hydrogen Peroxide Photosynthesis.

The production of hydrogen peroxide from natural seawater is green and sustainable. However, the efficiency of photocatalytic hydrogen peroxide production is low due to the degradation and poisoning of photocatalysts by the abundant ions in natural seawater. Precisely controlling the structure of photocatalysts to enhance their corrosion resistance and minimize the impact of external particles is a challenging task. Here, a novel molecular engineering strategy is reported in which confined Pd nanoclusters locked keto structures to enhance photocatalytic hydrogen peroxide production. Both experimental and theoretical findings reveals that Pd nanoclusters, when confined within a keto structure, not only bolster the stability of the photocatalyst but also augment the efficiency of photogenerated charge carriers' separation and transport. This dual enhancement significantly boosts the photocatalytic performance for hydrogen peroxide synthesis. One of the photocatalysts, TAPT-2KtTb Pd COF, exhibits an impressive photocatalytic hydrogen peroxide production rate of 2676.3µmol g-1 h-1, which is one of the highest values reported so far. Integral photocatalyzed H2O2 synthesis using confined Pd nanoclusters locked keto conformation COF provides a new insight for developing innovative photocatalysts for H2O2 synthesis.

Interaction of the Prominence Plasma within the Magnetic Cloud of an Interplanetary Coronal Mass Ejection with the Earth’s Bow Shock

The magnetic cloud within an interplanetary coronal mass ejection (ICME) is characterized by high magnetic field intensities. In this study, we investigate the interaction of a magnetic cloud carrying a density structure with the Earth’s bow shock during the ICME event on 2023 April 24. Elevated abundances of cold protons and heavier ions, namely, alpha particles and singly charged helium ions, associated with the prominence plasma are observed within this structure. The plasma downstream of the bow shock exhibits an irregular compression pattern, which could be due to the presence of heavy ions. Heavy ions carry a significant fraction of the upstream flow energy; however, due to their different mass-per-charge ratio and rigidity, they are less scattered by the electromagnetic and electrostatic waves at the shock. We find that downstream of the shock, while the ion thermal energy is only a small fraction of the background magnetic energy, nevertheless increased ion fluxes reduce the characteristic wave speeds in that region. As such, we observe a transition state of an unstable bow shock in which the plasma flow is super Alfvénic both upstream and downstream of the bow shock. Our findings help with the understanding of the intense space weather impacts of such events.

Finding environmental-friendly chemical synthesis with AI and high-throughput robotics

Recent environmental challenges have resulted in tremendous interest in Green Chemistry, which includes designing chemical products and processes that reduce the use of environmentally harmful substances. Until now, finding new environmental chemical synthesis has mainly been a trial-and-error process, requiring trained expertise and a lot of work. Here, we report a high-throughput process, combining AI techniques and robotic synthesis, allowing us to find a more environmentally friendly way to synthesize an existing material. The model materials in this study are to replace nitrate salts (NO3−), which might be responsible for algae bloom if leaked into open water, with a chloride salt (Cl−), a naturally abundant ion, in the synthesis of a metal-organic framework (MOF), Zn-HKUST-1. Our high-throughput process starts with using large language models (LLM)-based literature summary to create a database on the synthesis of Zn-HKUST-1 with NO3−, so that optimized concentrations of Cl− can be suggested. Subsequently, these suggestions are tested with automatic robotic processes, increasing the speed and precision of the experiments, and finding the optimal synthesis condition. Then, by using human verification as a foundation, we developed an AI-based automated classification algorithm to automatically sort the acquired images into crystals and non-crystals, focusing on low-resource settings. We successfully obtained MOF crystals from ZnCl2 precursors with this process, which proves that our process holds the promise to accelerate the discovery of new Green Chemistry processes.

Twisted BiOCl Moiré Superlattices for Photocatalytic Chloride Reforming of Methane.

Solar-driven conversion of CH4 into value-added methyl chlorides and H2 with abundant chloride ions offers a sustainable CH4 reforming strategy but suffers from inefficient Cl- activation and severe e--h+ recombination in traditional photocatalysts. Herein, we demonstrate that BiOCl moiré superlattices with a 11.1° twist angle are highly efficient for photocatalytic CH4 reforming into CH3Cl and H2 with NaCl. These moiré superlattices, featuring misalignment-induced tensile strains, destabilize surface Bi-Cl bonds, facilitating a hole-mediated MvK-analogous process to activate lattice Cl into reactive •Cl for CH4 chlorination. Meanwhile, their twisted stacking configurations reinforce interlayer electronic coupling and thus accelerate out-of-plane carrier transfer. Along with surface anchoring of single-atom Pt sites for H2 evolution, the resulting Pt1/BiOCl moiré superlattices deliver a CH3Cl yield of 53.4 μmol g-1 h-1 with an impressive selectivity of 96% under visible light. This study highlights the potential of lattice engineering in two-dimensional photocatalysts to regulate structural strains and carrier dynamics for the decentralized reforming of CH4.

Temperature-Dependent Trimethylamine N-Oxide Induced the Formation of Substance P Dimers.

Interactions of the peptide substance P (SP) (RPKPQQFFGLM-NH2) with trimethylamine N-oxide (TMAO) were investigated by using cryo-ion mobility-mass spectrometry (cryo-IM-MS), variable-temperature (278-358 K) electrospray ionization (vT-ESI) MS, and molecular dynamics (MD) simulations. Cryo-IM-MS provides evidence that cold solutions containing SP and TMAO yield abundant hydrated SP dimer ions, but dimer formation is inhibited in solutions that also contain urea. In addition, we show that SP dimer formation at cold solution temperatures (<298 K) is favored when TMAO interacts with the hydrophobic C-terminus of SP and is subject to reduced entropic penalty when compared to warmer solution conditions (>298 K). MD simulations show that TMAO lowers the free energy barrier for dimerization and that monomers dimerize by forming hydrogen bonds (HBs). Moreover, differences in oligomer abundances for SP mutants (P4A, P2,4A, G9P, and P2,4A/G9P) provide evidence that oligomerization facilitated by TMAO is sensitive to the cis/trans orientation of residues at positions 2, 4, and 9.

Biogeochemistry of Actinides: Recent Progress and Perspective.

Actinides are elements that are often feared because of their radioactive nature and potentially devastating consequences to humans and the environment if not managed properly. As such, their chemical interactions with the biosphere and geochemical environment, i.e., their "biogeochemistry," must be studied and understood in detail. In this Review, a summary of the past discoveries and recent advances in the field of actinide biogeochemistry is provided with a particular emphasis on actinides other than thorium and uranium (i.e., actinium, neptunium, plutonium, americium, curium, berkelium, and californium) as they originate from anthropogenic activities and can be mobile in the environment. The nuclear properties of actinide isotopes found in the environment and used in research are reviewed with historical context. Then, the coordination chemistry properties of actinide ions are contrasted with those of common metal ions naturally present in the environment. The typical chelators that can impact the biogeochemistry of actinides are then reviewed. Then, the role of metalloproteins in the biogeochemistry of actinides is put into perspective since recent advances in the field may have ramifications in radiochemistry and for the long-term management of nuclear waste. Metalloproteins are ubiquitous ligands in nature but, as discussed in this Review, they have largely been overlooked for actinide chemistry, especially when compared to traditional environmental chelators. Without discounting the importance of abundant and natural actinide ions (i.e., Th4+ and UO2 2+), the main focus of this review is on trivalent actinides because of their prevalence in the fields of nuclear fuel cycles, radioactive waste management, heavy element research, and, more recently, nuclear medicine. Additionally, trivalent actinides share chemical similarities with the rare earth elements, and recent breakthroughs in the field of lanthanide-binding chelators may spill into the field of actinide biogeochemistry, as discussed hereafter.

Electrochemical Performance of MoB/Si3N4 Heterojunction as a Potential Anode Material for Li Ion Batteries.

In response to the current policy of high storage capacity, two-dimensional (2D) materials have revealed promising prospects as high-performance electrode materials. MoB, as a type of such material, is widely regarded as an anode candidate for Li-ion batteries due to its large specific surface area and abundant ion diffusion channels; the long-term cycling stability, however, is poor owing to material pulverization during the cycle. Therefore, MoB/Si3N4 heterojunction in this work is proposed as an anode material, with Si3N4 acting as a skeleton, maintaining the stability of the structure, while retaining the high energy storage properties of MoB as well. In addition, a certain built-in electric field is formed between them, which can play a role in regulating charge transfer, improving the ion transport channel, and accelerating the migration rate. Herein, the structural, electronic, and electrochemical properties are systematically investigated by first-principles calculations; the final results indicate that the heterojunction anode material does indeed have built-in electric fields, which promote the anode material to possess excellent electrical conductivity and outstanding electrochemical property. Meanwhile, the introduction of vacancy defects can bolster the diffusion kinetic performance of ion transport and greatly reduce the diffusion energy barrier of Li ions, which is conducive to the realization of rapid charge and discharge for the Li ion battery. Based on the synergistic effect of two single-component materials, the synthesized anode material displays a high theoretical capacity of 461 mAh/g, and the calculated open-circuit voltage is 0.66 V, within the range of the negative electrode criterion of 0-1 V, which can effectively play a role in preventing the formation of Li dendrites; these properties are comparable to other 2D anode materials as well. Given these intriguing properties, the MoB/Si3N4 heterojunction is an exceptional candidate for advanced LIB high-performance anode materials.

Diversified competitive sulfuration behaviors of concomitant heavy metal ions on copper recovery from copper smelting waste acid

Currently, sulfuration is widely used for the Cu(II) recovery from copper smelting waste acids (CSWA). However, the abundant concomitant heavy metal ions (HMIs) seriously obstruct Cu(II) recovery. In this paper, we find that the precipitation difficulty of HMI sulfide is determined by solubility product constant (Ksp), H+ concentration and S(−II) concentration, resulting in the diversified competitive sulfuration behaviors of concomitant HMIs on Cu(II) recovery. For concomitant HMIs without S(−II)-consuming ability, the positive-side competitive sulfuration behaviors on Cu(II) recovery are in the order of In(III) > Zn(II) > Ni(II) > Fe(II) > Mn(II). However, with the formation of concomitant HMIs sulfides, the negative-side competitive sulfuration behaviors on Cu(II) recovery are in the order of Fe(III) > As(III) > Bi(III) > Cd(II). According to the results of diffusion-growth-dissolution model, the S(−II)-combining process on HMIs surface is divided into S(−II)-capturing and S(−II)-consuming stages, related to Ksp value and HMIs precipitation, respectively. In actual CSWA, 5000 ∼ 15000 mg/L As(III) seriously inhibits the recovery efficiency of 500 ∼ 2000 mg/L Cu(II), and other concomitant HMIs (e.g., 250 ∼ 1200 mg/L Zn(II), 300 ∼ 450 mg/L Cd(II), 10 ∼ 200 mg/L Bi(III) and 20 ∼ 200 mg/L Fe(II)) will further affect Cu(II) recovery. Besides, ignoring these diversified competitive sulfurations of concomitant HMIs induces unreasonable S(−II) concentration for complete Cu(II) recovery, resulting in Cu(II) recovery issues: As(III) precipitation and Cu(II) residue. Thus, timely information in instantaneous Cu(II) concentration is a feasible strategy to accurately adjust S(−II) concentration via Cu(II) quantitative model. This work is devoted to the efficient and controllable recovery of Cu resources and the reduction of As-containing hazardous wastes in sulfuration treatment of actual CSWA.

Distinct association of HRAS and KRAS with Mn(II) ion illustrated by paramagnetic NMR

Rat sarcoma virus oncogene (RAS) proteins are among crucial oncogenic proteins and are involved in several essential intracellular processes. The RAS protein has an intrinsic metal binding site for Mg2+, which is important for the conformational stability of the active site. Recently, it was reported that a second metal ion binding site, located further from the active site in HRAS (Harvey RAS homolog), binds Ca2+ with millimolar affinity. As one of the most abundant metal ions in cells, Mn2+ is a potential candidate for the second metal ion binding site in RAS proteins. Here, we examined the interaction of Mn2+ with HRAS and KRAS (Kirsten RAS homolog) using high resolution NMR spectroscopy. The NMR data showed that both the second metal ion binding site and the switch I and II regions bind Mn2+ in the RAS proteins. Furthermore, our paramagnetic NMR results disclosed the conformational differences in helix α3 and the following loop between HRAS and KRAS, accompanied by the association with metal ion binding. These results provide new insights into the interaction of RAS proteins and Mn2+ in the respective biological processes in cells.

Metallicity calibrations based on auroral lines from PHANGS–MUSE data

We present a chemical analysis of selected H II regions from the PHANGS-MUSE nebular catalogue. Our intent is to empirically re-calibrate strong-line diagnostics of gas-phase metallicity, applicable across a wide range of metallicities within nearby star-forming galaxies. To ensure reliable measurements of auroral line fluxes, we carried out a new spectral fitting procedure whereby only restricted wavelength regions around the emission lines of interest are taken into account: this assures a better fit for the stellar continuum. No prior cuts to nebulae luminosity were applied to limit biases in auroral line detections. Ionic abundances of O+, O2+, N+, S+, and S2+ were estimated by applying the direct method. We integrated the selected PHANGS-MUSE sample with other existing auroral line catalogues, appropriately re-analysed to obtain a homogeneous dataset. This was used to derive strong-line diagnostic calibrations that span from 12 + log(O/H) = 7.5 to 8.8. We investigate their dependence on the ionisation parameter and conclude that it is likely the primary cause of the significant scatter observed in these diagnostics. We apply our newly calibrated strong-line diagnostics to the total sample of H II regions from the PHANGS-MUSE nebular catalogue, and we exploit these indirect metallicity estimates to study the radial metallicity gradient within each of the 19 galaxies of the sample. We compare our results with the literature and find good agreement, validating our procedure and findings. With this paper, we release the full catalogue of auroral and nebular line fluxes for the selected H II regions from the PHANGS-MUSE nebular catalogue. This is the first catalogue of direct chemical abundance measurements carried out with PHANGS-MUSE data.

Aqueous photochemical aging of water-soluble smoke particles from crop straws burning

Most aqueous oxidation studies focus on single model precursors, while the photochemical aging of actual water soluble organic matter (WSOM) in particles emitted from biomass burning remains poorly understood. In this study, gas chromatography-mass spectrometry (GC/MS) was first used to analyze the WSOM in smoke particles emitted from three crop straws burning. The results show that the dominant WSOM in three crop straws (CS) smoke are phenolic substances with small differences. Aqueous photochemical aging of WSOM in CS smoke was investigated under simulated sunlight exposure. High-resolution aerosol mass spectrometry (HR-AMS) analyzed aqueous secondary organic aerosol (aqSOA) and it was found that the oxidation degree of aqSOA increased with prolonged aging. No obvious increase in the abundance of N-containing organic ions was observed over the course of aqueous aging. As aqueous aging progresses, the pH of the solution gradually decreases, accompanied by the continuous generation of organic acids. Studies on dithiothreitol (DTT) activity indicate that the impact of aqueous photochemical aging on health is not significant.The solution after photoaging shows relatively lower light absorption ability than the initial solution. The aqueous photochemical aging also led to a gradual reduction of fluorescence at excitation/emission = 250–260 nm/350 nm (protein-like substances) for CS smoke WSOM, suggesting the significant degradation of chromophores. However, three-dimensional excitation-emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC) revealed that aqueous aged CS smoke WSOM contains compounds with high humification index, confirming that the fluorophore composition is altered by aqueous aging. The humic-like substance (HULIS) concentration increased for the first 3 h and then decreased, closely matching the pattern of a new fluorescence peak. Finally, GC/MS analysis of the products indicated that there was obvious decline in proportion of methoxyphenol. The results of this study are important for understanding the aqueous-phase oxidation reactions of CS smoke WSOM in the atmosphere and their light-absorption characteristics and health impacts.

Ionic wind produced by volume corona discharges and surface dielectric barrier discharges: What role do streamers play?

The present study compares the ionic wind produced by volume DC and AC corona discharges, and by surface dielectric barrier discharges (DBD). On the one hand, in the case of a volume corona discharge ignited between a high-voltage needle and a grounded plate, our measurements highlight that the ionic wind velocity increases in the presence of positive breakdown streamers. On the other hand, in the case of a surface AC DBD, the ionic wind velocity decreases when streamers occur. Why such a difference? The answer is not easy and the debate remains open. However, one answer would be that the streamers occurring in a volume needle-to-plate discharge leave an abundance of positive ions in the inter-electrode space and that these ions drift because of the electric field, just after the streamer propagation. On the other hand, in the case of a surface DBD, the streamers can leave positive ions in their wake but their heads especially deposit positive ions at the location where they stop propagating, i.e. a few millimetres from the electrode (up to about 10–15 mm). Then this positive space charge deposited at a few millimetres from the active electrode edge on the dielectric surface acts as a screen against the electric field due to the applied high voltage, thus preventing the drift of the ions remaining on the surface of the dielectric, close to the electrode edge. Having said that, the reality is that this explanation is certainly very simplistic compared with the very complex phenomena taking place in these two discharges, particularly at the times when the streamers form and propagate.

Measurement Uncertainty and Validation for Quantification of Marijuana Metabolite: (−)-11-nor-9-Carboxy-Δ9-THC in Human Urine by GC-MS/MS

Background: Since the International Olympic Committee (IOC) was established, sports doping control analyses have revealed a high rate of positive cases for cannabinoids. Cannabinoids were banned in all sports where they were used in competition as per the Prohibited List published annually. Further, it was also included in the threshold drug category. Consequently, developing a reliable method for urine Cannabinoids metabolite quantification plays a pivotal role in sports dope testing. Objective: This work aimed to develop and validate a reliable, cost-effective, robust gas chromatography-tandem mass spectrometry method for detecting (−)-11-nor-9-Carboxy-Δ9- THC component in human urine samples, in compliance with ICH and WADA guidelines. Method: The sample preparation was done by enzymatic hydrolysis for deconjugation, further proceeded with solid phase extraction (SPE), liquid-liquid extraction (LLE), and using an XAD2 column, and N-methyl trimethylsilyl trifluoroacetamide (MSTFA) for derivatization. Results: The linearity was obtained in a range of 50–300 ng/mL, and the correlation coefficient was found to be higher than 0.99. Throughout the entire validation study, the difference in Retention Time (RT) for the analyte, including the Internal Standard (IS), was shown to be less than 1.0%. The quantification limit (LOQ) was calculated at a level of 50 ng/mL in human urine samples for the 3 most abundant ion transitions. The detection limit (LOD) was established at 4 ng/mL. Conclusion: The accuracy, precision, linearity, recovery, quantification limit, and selectivity by GC-MS/MS technique were found acceptable and well satisfactory while following the ICH guidelines. The developed method has been proven to be fit for purpose in accordance with the enforced Guidelines of WADA.

Zinc ions activate AKT and promote prostate cancer cell proliferation via disrupting AKT intramolecular interaction.

Prostate is a zinc rich organ and the physiological function of the abundant zinc ions is relatively less understood. AKT kinase is a pivotal regulator downstream of cytokines, growth factors and other extracellular stimuli, and the attachment of its PH domain to PtdIns-3,4,5-P3 (PIP3) and the subsequent phosphorylation of its kinase domain by PDPK1 are considered important for its activation. Herein, we report a regulatory mechanism of AKT kinase by zinc ions. Mechanistically, zinc ions directly bind to AKT and facilitate AKT activation through disrupting the interaction between PH and kinase domains within AKT molecule. Consistently, AKT1-H89A/E91A mutant (zinc-binding-deficient) fails to respond to zinc ions and exhibits strong interaction between PH and kinase domains, and it is less oncogenic in orthotopic xenograft model of prostate cancer. On the other hand, the AKT1-W80L mutant with minimum intra-molecular interaction between PH and kinase domains shows strong tumor promoting capacity although it could not be further stimulated by zinc ions. Overall, this study reveals a distinctive regulatory mechanism of AKT activation and implies a tumor promoting role of the zinc ions in prostate cancer.

Comparative study of silica-based porous materials in the purification of radioactive wastewater

A significant challenge in the treatment of low-level radioactive wastewater is the effective purification of low-concentration radionuclides. Silica-based adsorbents are advantageous for the deep-purification of low-concentration metal ions. This study investigates three primary types of silica-based adsorbents: functionalized mesoporous silica, various modified zeolites, and mesoporous calcium silicate hydrate (C-S-H). These adsorbents were synthesized and their deep-purification effects on heavy metals and radionuclides were compared. The results indicated that mesoporous silica showed relatively poor adsorption for most metal ions. Zeolites outperformed mesoporous silica, with Zn framework-modified zeolites showing enhanced adsorption for several metal ions. Notably, C-S-H displayed superior adsorption performance, achieving high adsorption capacities for various metal ions and radionuclides. Specifically, at a dose of 0.5 g/L, the adsorption efficiency of C-S-H for numerous radionuclides in nuclear power plant wastewater exceeded 92–99 %, highlighting its potential for practical applications. An in-depth analysis of the physical and chemical structure and the adsorption mechanisms of C-S-H revealed its large mesoporous structure and electrostatic attraction to cations across a wide pH range. Multivalent cations were removed through exchange with Ca2+ in C-S-H, whereas monovalent cations were removed through exchange with Na+ in C-S-H. The cyclic structure of silica-oxygen tetrahedra in C-S-H, which promotes large pore formation and provides abundant ion exchange sites, underpins its excellent adsorption properties. This study offers valuable insights for the selection and application of silica-based materials in radioactive wastewater treatment.