Historical co-enrichment, source attribution, and risk assessment of critical nutrients and heavy metal/metalloids in lake sediments: insights from Chaohu Lake, China.

In Chinese freshwater lakes, eutrophication often coincides with heavy metal/metalloids (HM/Ms) pollution, yet the coevolution of critical nutrients (P, S, Se) and HM/Ms (Cd, Hg, etc.) remains understudied. To address this gap, we conducted a sedimentary chemistry analysis on a 30 cm-deep core, dating back approximately 200 years, retrieved from Chaohu Lake, China. The age-depth model revealed a gradual increase in deposition rates over time. Notably, the concentrations and enrichment factors (EFs) of most target elements surged in the uppermost ~ 15 cm layer, covering the period from 1953 to 2013, while both the concentrations and EFs in deeper layers remained relatively stable, except for Hg. This trend indicates a significant co-enrichment and near-synchronous increase in the levels and EFs of both nutrients and HM/Ms in the upper sediment layers since the mid-twentieth century. Anthropogenic factors were identified as the primary drivers of the enrichment of P, Se, Cd, Hg, Zn, and Te in the upper core, with their contributions also showing a coupled evolutionary trend over time. Conversely, geological activities governed the enrichment of elements in the lower half of the core. The gradual accumulation of anthropogenic Hg between the - 30 to - 15 cm layers might be attributed to global Hg deposition resulting from the industrial revolution. The ecological risk index (RI) associated with HM/Ms loading has escalated rapidly over the past 50 years, with Cd and Hg posing the greatest threats. Furthermore, the PMF model was applied to specifically quantify source contributions of these elements in the core, with anthropogenic and geogenic factors accounting for ~ 60 and ~ 40%, respectively. A good correlation (r2 = 0.87, p < 0.01) between the PMF and Ti-normalized method was observed, indicating their feasibility and cross-validation in source apportionment. Finally, we highlighted environment impact and health implications of the co-enrichment of nutrients and HM/Ms. This knowledge is crucial for developing strategies to protect freshwater ecosystems from the combined impacts of eutrophication and HM/Ms pollution, thereby promoting water environment and human health.

Mn-inlaid antiphase boundaries in perovskite structure.

Improvements in the polarization of environmentally-friendly perovskite ferroelectrics have proved to be a challenging task in order to replace the toxic Pb-based counterparts. In contrast to common methods by complex chemical composition designs, we have formed Mn-inlaid antiphase boundaries in Mn-doped (K,Na)NbO3 thin films using pulsed laser deposition method. Here, we observed that mono- or bi-atomic layer of Mn has been identified to inlay along the antiphase boundaries to balance the charges originated from the deficiency of alkali ions and to induce the strain in the KNN films. Thus, rectangular saturated polarization-electric field hysteresis loops have been achieved, with a significantly improved twice remanent polarization of 114 µC/cm2 with an applied electric field of 606 kV/cm, which can be comparable to that of the typical Pb-based thin films. Moreover, we directly see the Mn occupation at the A-site of KNN perovskite structure using atomic-scale microstructure and composition analysis. The Mn-inlaid antiphase boundary can further enrich the understanding of perovskite crystal structure and give more possibilities for the design and optimization of perovskite materials.

2D Se-Rich ZnSe/CoSe2@C Heterostructured Composite as Ultrastable Anodes for Alkaline-Ion Batteries.

2D transitional metal selenide heterostructures are promising electrode materials for potassium-ion batteries (PIBs) owing to the large surface area, high mechanical strength, and short diffusion pathways. However, the cycling performance remains a significant challenge, particularly concerning the electrochemical conversion reaction. Herein, 2D Se-rich ZnSe/CoSe2@C heterostructured composite is fabricated via a convenient hydrothermal approach followed by selenization process, and then applied as high-performance anodes for PIBs. For example, the capacity delivered by the heterostructured composite is mainly contributed to the synergistic effect of conversion and alloy/de-alloy processes aroused by K+, where K+ may highly insert or de-insert into Se-rich ZnSe/CoSe2@C. The obtained electrode delivers an outstanding reversible charge capacity of 214 mA h g-1 at 1 A g-1 after 4000 cycles for PIBs, and achieves 262 mAh g-1 when coupled with a PTCDA cathode in the full cell. The electrochemical conversion mechanism of the optimized electrode during cycling is investigated through in situ XRD, Raman, and ex situ HRTEM. In addition, the heterostructured composite as anodes also displays excellent electrochemical performances for sodium-ion batteries (SIBs) and lithium-ion batteries (LIBs). This work opens up a new window for investigating novel electrode materials with excellent capacity and long durability.

Bimetallic Sulfide Hollow Nanocubes Heterostructure Promotes Dual Coupling of Conversion and Alloying/Dealloying Reactions to Achieve Durable Potassium-Ion Battery Anode.

Conversion and alloying-type transitional metal sulfides have attracted significant interests as anodes for Potassium-ion batteries (PIBs) and Sodium-ion batteries (SIBs) due to their high theoretical capacities and low cost. However, the poor conductivity, structural pulverization, and high-volume expansions greatly limit the performance. Herein, Co1-xS/ZnS hollow nanocube-like heterostructure decorated on reduced graphene oxide (Co1-xS/ZnS@rGO) composite is fabricated through convenient hydrothermal and post-heat vulcanization techniques. This unique composite can provide a more stable conductive network and shorten the diffusion length of ions, which exhibits a remarkable initial charge capacity of 638.5 mA h g-1 at 0.1 A g-1 for SIBs and 606 mA h g-1 at 0.1 A g-1 for PIBs, respectively; It is worth noting that the composite presents remarkable long stable cycle performance in PIBs, which initially delivered 274 mA h g-1 and sustained the charge capacity up to 245 mA h g-1 at high current density of 1 A g-1 after 2000 cycles. A series of in situ/ex situ detections and first principle calculations further validate the high potassium ions adsorption ability of Co1-xS/ZnS anode materials with high diffusion kinetics. This work will accelerate the fundamental construction of bimetallic sulfide hollow nanocubes heterostructure electrodes for energy storage applications.

Neuroprotection of Human Umbilical Cord-Derived Mesenchymal Stem Cells (hUC-MSCs) in Alleviating Ischemic Stroke-Induced Brain Injury by Regulating Inflammation and Oxidative Stress.

Brain injury caused by stroke has a high rate of mortality and remains a major medical challenge worldwide. In recent years, there has been significant attention given to the use of human Umbilical cord-derived Mesenchymal Stem Cells (hUC-MSCs) for the treatment of stroke in different adult and neonate animal models of stroke. However, using hUC-MSCs by systemic administration to treat ischemic stroke has not been investigated sufficiently. In this study, we conducted various experiments to explore the neuroprotection of hUC-MSCs in rats. Our findings demonstrate that an intravenous injection of a high dose of hUC-MSCs at 2 × 10^7 cells/kg markedly ameliorated brain injury resulting from ischemic stroke. This improvement was observed one day after inducing transient middle cerebral artery occlusion (MCAO) and subsequent reperfusion in rats. Notably, the efficacy of this single administration of hUC-MSCs surpassed that of edaravone, even when the latter was used continuously over three days. Mechanistically, secretory factors derived from hUC-MSCs, such as HGF, BDNF, and TNFR1, ameliorated the levels of MDA and T-SOD to regulate oxidative stress. In particular, TNFR1 also improved the expression of NQO-1 and HO-1, important proteins associated with oxidative stress. More importantly, TNFR1 played a significant role in reducing inflammation by modulating IL-6 levels in the blood. Furthermore, TNFR1 was observed to influence the permeability of the blood-brain barrier (BBB) as demonstrated in the evan's blue experiment and protein expression of ZO-1. This study represented a breakthrough in traditional methods and provided a novel strategy for clinical medication and trials.

Anionic Chemistry Modulation Enabled Environmental Self-Charging Aqueous Zinc Batteries: The Case of Carbonate Ions.

Anionic chemistry modulation represents a promising avenue to enhance the electrochemical performance and unlock versatile applications in cutting-edge energy storage devices. Herein, we propose a methodology that involves anionic chemistry of carbonate anions to tailor the electrochemical oxidation-reduction reactions of bismuth (Bi) electrodes, where the conversion energy barrier for Bi (0) to Bi (III) has been significantly reduced, endowing anionic full batteries with enhanced electrochemical kinetics and chemical self-charging property. The elaborately designed batteries with an air-switch demonstrate rapid self-recharging capabilities, recovering over 80 % of the electrochemical full charging capacity within a remarkably short timeframe of 1 hour and achieving a cumulative self-charging capacity of 5 Ah g-1. The aqueous self-charging battery strategy induced by carbonate anion, as proposed in this study, holds the potential for extending to various anionic systems, including seawater-based Cl- ion batteries. This work offers a universal framework for advancing next-generation multi-functional power sources.

Reconstructing a 300-year history of phosphorus cycle in west Chaohu Lake, China.

Anthropogenic activities could significantly increase nutrients loading, especially phosphorus (P), into aquatic systems, leading to eutrophication and disturbance of ecosystems. Detailed investigation of P cycling and its controlling factors in modern lakes could help understand mechanisms behind eutrophication, thus provide suggestions for future environmental management. Here, we investigate evolution history of P and iron (Fe) cycling over the last ∼300 years in west Chaohu Lake, a typical eutrophic lake in East China. The combination of 210Pb-137Cs dating and elemental analysis demonstrates drastic escalation of P input and organic carbon burial since 1960s, coincided with the rapid growth of human population near this region. P phase partitioning data indicate that Fe-bound P (PFe) is the predominant P pool of sediments in Chaohu Lake, which also regulates the evolving trend of reactive P (Preac). Moreover, the highest fraction of PFe is consistent with observations via P K-edge X-ray absorption near edge structure (P XANES). In addition, Fe speciation results show a principal contribution of Fe (hydr)oxides (Feox) and negligible presence of pyrite, suggesting a generally oxygenated depositional environment, where P could be preferentially sequestrated in sediments in association with Fe oxide minerals. Relatively high molar organic carbon/organic P (Corg/Porg) but low Corg/Preac ratios also support limited recycling of Preac in west Chaohu Lake. This study reveals that human activities play an important role in leading to the eutrophication of Chaohu Lake. Future environmental management could utilize the coupling of P and Fe oxides to remove P from water column.

A pediatric patient with bilateral tracheobronchial foreign body successfully treated using surgical intervention with extracorporeal circulation: case report and literature review.

Unilateral Tracheobronchial foreign body (TFB) present a common clinical disease, whereas bilateral TFB is a rare and acute condition associated with high mortality rates. This case study discusses a pediatric patient hospitalized due to respiratory distress following accidental ingestion of peanut kernels. A plain chest CT scan revealed obstructive emphysema in the right main bronchus and a foreign body at the opening of the left main bronchus. Surgical removal of the bilateral TFB under extracorporeal circulation resulted in a successful postoperative recovery, leading to discharge on the 9th day. A comprehensive literature search was conducted across databases including PubMed, Web of Science, EMBASE, Cochrane Library, and CNKI, spanning publications from January 2014 to October 2023, utilizing keywords "bronchial foreign body" and "Peanut". After deduplication and relevance screening, 9 pertinent literature sources were included. The objective of this study is to enhance clinical practitioners' understanding of TFB management and improve diagnostic and treatment capabilities through analysis of age of onset, clinical manifestations, diagnosis, and treatment approaches in critically ill pediatric patients.

Manipulating Atomic-Coupling in Dual-Cavity Boride Nanoreactor to Achieve Hierarchical Catalytic Engineering for Sulfur Cathode.

The catalytic process of Li2S formation is considered a key pathway to enhance the kinetics of lithium-sulfur batteries. Due to the system's complexity, the catalytic behavior is uncertain, posing significant challenges for predicting activity. Herein, we report a novel cascaded dual-cavity nanoreactor (NiCo-B) by controlling reaction kinetics, providing an opportunity for achieving hierarchical catalytic behavior. Through experimental and theoretical analysis, the multilevel structure can effectively suppress polysulfides dissolution and accelerate sulfur conversion. Furthermore, we differentiate the adsorption (B-S) and catalytic effect (Co-S) in NiCo-B, avoiding catalyst deactivation caused by excessive adsorption. As a result, the as-prepared battery displays high reversible capacity, even with sulfur loading of 13.2 mg cm-2 (E/S=4 µl mg-1), the areal capacity can reach 18.7 mAh cm-2.

A NiMOF integrated with conductive materials for efficient bifunctional electrocatalysis of urea oxidation and oxygen evolution reactions.

The development of urea oxidation reaction (UOR) and oxygen evolution reaction (OER) bifunctional electrocatalysts has dual significance in promoting hydrogen energy production and urea-rich wastewater treatment. Herein, a carboxylated multi-walled carbon nanotube (MWCNT-COOH)-ferrocene carboxylic acid (Fc-COOH) modulated NiMOF hybrid material (MWCNT-NiMOF(Fc)) has been synthesized for dual electrocatalysis of the UOR and OER. The material characterization results indicated that MWCNT-COOH and Fc-COOH were integrated into the framework structure of the NiMOF. The direct interaction between the NiMOF and MWCNT/Fc facilitated electron transfer in the hybrid material and led to lattice strain, which improved the charge transfer kinetics, promoted the exposure of more unsaturated Ni sites, and increased the electrochemically active surface area. These factors together enhanced the electrocatalytic activity of MWCNT-NiMOF(Fc) towards the UOR and OER. Using a glassy carbon electrode as the substrate, MWCNT-NiMOF(Fc) exhibited low potential requirements, low Tafel slopes, and high stability. In overall urea and water splitting electrolysis cells, the excellent UOR and OER dual functional catalytic ability and enormous practical application potential of the MWCNT-NiMOF(Fc) modified foam nickel electrode were further demonstrated. On the basis of the above research, the influence of a KOH environment on urea electrolysis was further studied, and the urea electrolysis products were analyzed, promoting a more comprehensive understanding of the catalytic performance of MWCNT-NiMOF(Fc) for urea oxidation. This study provides a new approach for developing high-performance NiMOF-based electrocatalysts for challenging bifunctional UOR/OER applications, and has potential application value in hydrogen production from urea-containing wastewater electrolysis.

SLC7A8 overexpression inhibits the growth and metastasis of lung adenocarcinoma and is correlated with a dismal prognosis.

BACKGROUND: Overexpression of solute carrier family 7 member 8 (SLC7A8) has been shown to relate to the survival time and tumor progression in cancer patients. However, the role of SLC7A8 in lung adenocarcinoma (LUAD) is still obscure. METHOD: The relationships between SLC7A8 expression in LUAD tissues and clinical values as well as immune infiltration were explored through bioinformatics. The functions and pathways of SLC7A8 in LUAD were investigated using Kyoto Encyclopedia of Genes and Genomes enrichment analysis, Gene Set Enrichment Analysis, Western blotting, and other methods. RESULTS: We found that the expression of SLC7A8 was decreased significantly in LUAD tissues compared with normal tissues, which was related to the dismal survival time and disease progression. Moreover, it carried diagnostic value in LUAD and was a risk factor for dismal prognosis. Receiver operating characteristic curve analysis indicated that the expression level of SLC7A8 carried significant diagnostic value in LUAD. Overexpression of SLC7A8 inhibited the proliferation, invasion, and migration of LUAD cells, likely through a mechanism involving the cell cycle. SLC7A8 expression in LUAD was significantly correlated with the infiltration of immune cells, especially B cells, interstitial dendritic cells, mast cells, CD56 bright cells, natural killer cells, plasmacytoid dendritic cells, T follicular helper cells, T helper 2 and 17 cells, and immune factors. CONCLUSION: The downregulation of SLC7A8 was related to a dismal prognosis and immune cell infiltration in LUAD. Increasing the expression of SLC7A8 inhibited the growth and migration of LUAD cells, thereby improving the prognosis of patients.

Overexpression of MTFR1 promotes cancer progression and drug-resistance on cisplatin and is related to the immune microenvironment in lung adenocarcinoma.

OBJECTIVE: The roles of MTFR1 in the drug resistance of lung adenocarcinoma (LAC) to cisplatin remain unexplored. In this study, the expression, clinical values and mechanisms of MTFR1 were explored, and the relationship between MTFR1 expression and immune microenvironment was investigated in LAC using bioinformatics analysis, cell experiments, and meta-analysis. METHODS: MTFR1 expression and clinical values, and the relationship between MTFR1 expression and immunity were explored, through bioinformatics analysis. The effects of MTFR1 on the growth, migration and cisplatin sensitivity of LAC cells were identified using cell counting kit-8, wound healing and Transwell experiments. Additionally, the mechanisms of drug resistance of LAC cells involving MTFR1 were investigated using western blotting. RESULTS: MTFR1 was elevated in LAC tissues. MTFR1 overexpression was associated with sex, age, primary therapy outcome, smoking, T stage, unfavourable prognosis and diagnostic value and considered an independent risk factor for an unfavourable prognosis in patients with LAC. MTFR1 co-expressed genes involved in the cell cycle, oocyte meiosis, DNA replication and others. Moreover, interfering with MTFR1 expression inhibited the proliferation, migration and invasion of A549 and A549/DDP cells and promoted cell sensitivity to cisplatin, which was related to the inhibition of p-AKT, p-P38 and p-ERK protein expression. MTFR1 overexpression was associated with stromal, immune and estimate scores along with natural killer cells, pDC, iDC and others in LAC. CONCLUSIONS: MTFR1 overexpression was related to the unfavourable prognosis, diagnostic value and immunity in LAC. MTFR1 also participated in cell growth and migration and promoted the drug resistance of LAC cells to cisplatin via the p-AKT and p-ERK/P38 signalling pathways.

Co/Mon Invigorated Bilateral Kinetics Modulation for Advanced Lithium-Sulfur Batteries.

Sluggish sulfur redox kinetics and Li-dendrite growth are the main bottlenecks for lithium-sulfur (Li-S) batteries. Separator modification serves as a dual-purpose approach to address both of these challenges. In this study, the Co/MoN composite is rationally designed and applied as the modifier to modulate the electrochemical kinetics on both sides of the sulfur cathode and lithium anode. Benefiting from its adsorption-catalysis function, the decorated separators (Co/MoN@PP) not only effectively inhibit polysulfides (LiPSs) shuttle and accelerate their electrochemical conversion but also boost Li+ flux, realizing uniform Li plating/stripping. The accelerated LiPSs conversion kinetics and excellent sulfur redox reversibility triggered by Co/MoN modified separators are evidenced by performance, in-situ Raman detection and theoretical calculations. The batteries with Co/MoN@PP achieve a high initial discharge capacity of 1570 mAh g-1 at 0.2 C with a low decay rate of 0.39%, uniform Li+ transportation at 1 mA cm-2 over 800 h. Moreover, the areal capacity of 4.62 mAh cm-2 is achieved under high mass loadings of 4.92 mg cm-2. This study provides a feasible strategy for the rational utilization of the synergistic effect of composite with multifunctional microdomains to solve the problems of Li anode and S cathode toward long-cycling Li-S batteries.

Connection between health risk and heavy metals in agricultural soils of China: a study based on current field investigations.

Heavy metal pollution in agricultural soil is a threat to people's health and sustainable development. However, there is currently no nationwide health risk assessment in China. In this study, we performed a preliminary assessment of heavy metals in agricultural soils of the Chinese mainland, and found obvious carcinogenic risks (total lifetime carcinogenic risk (TLCR) > 1 × 10-5). A similar spatial distribution pattern was found in soil heavy metal and the mortality of esophagus and stomach cancers. Combining the potential carcinogenic risk assessed by LCR for individual heavy metal with Pearson correlation, Geographical Detector (q statistic > 0.75 for TLCR, p < 0.05), and redundancy analysis (RDA), it was found that long-term exposure and intake route of heavy metals exceeding the maximum safety threshold (Health Canada standard) may induce digestive system (esophagus, stomach, liver, and colorectum) cancers in rural populations. Through Partial Least Squares Path Model (PLS-PM), it was also revealed that the LCR of heavy metals was closely related to the soil environmental background (path coefficients = 0.82), which in turn was affected by factors such as economic development and pollution discharge. The current research results highlight the potential carcinogenic risk to the digestive system associated with low-dose and long-term exposure to heavy metals in agricultural soils, and policymakers should propose countermeasures and solutions according to the local conditions.

A General "In Situ Etch-Adsorption-Phosphatization" Strategy for the Fabrication of Metal Phosphides/Hollow Carbon Composite for High Performance Liquid/Flexible Zn-Air Batteries.

Benefiting from the admirable energy density (1086 Wh kg-1 ), overwhelming security, and low environmental impact, rechargeable zinc-air batteries (ZABs) are deemed to be attractive candidates for lithium-ion batteries. The exploration of novel oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) bifunctional catalysts is the key to promoting the development of zinc-air batteries. Transitional metal phosphides (TMPs) especially Fe-based TMPs are deemed to be a rational type of catalyst, however, their catalytic performance still needs to be further improved. Considering Fe (heme) and Cu (copper terminal oxidases) are nature's options for ORR catalysis in many forms of life from bacteria to humans. Herein, a general "in situ etch-adsorption-phosphatization" strategy is designed for the fabrication of hollow FeP/Fe2 P/Cu3 P-N, P codoped carbon (FeP/Cu3 P-NPC) catalyst as the cathode of liquid and flexible ZABs. The liquid ZABs manifest a high peak power density of 158.5 mW cm-2 and outstanding long-term cycling performance (≈1100 cycles at 2 mA cm-2 ). Similarly, the flexible ZABs deliver superior cycling stability of 81 h at 2 mA cm-2 without bending and 26 h with different bending angles.

Self-Powered Integrated Sensing System with In-Plane Micro-Supercapacitors for Wearable Electronics.

Self-powered integrated sensor with high-sensitivity physiological signals detection is indispensable for next-generation wearable electronic devices. Herein, a Ti3 C2 Tx /CNTs-based self-powered resistive sensor with solar cells and in-plane micro-supercapacitors (MSCs) is successfully realized on a flexible styrene-ethylene/butylene-styrene (SEBS) electrospinning film. The prepared Ti3 C2 Tx /CNTs@SEBS/CNTs nanofiber membranes exhibit high electrical conductivity and mechanical flexibility. The laser-assisted fabricated Ti3 C2 Tx /CNTs based-MSCs demonstrate a high areal energy density of 52.89 and 9.56 µWh cm-2 with a corresponding areal power density of 0.2 and 4 mW cm-2 . Additionally, the MSCs exhibit remarkable capacity retention of 90.62% after 10 000 cycles. Furthermore, the Ti3 C2 Tx /CNTs based-sensor exhibits real-time detection capability for human facial micro-expressions and pulse single under physiological conditions. The repeated bending/release tests indicate the long-time cycle stability of the Ti3 C2 Tx /CNTs based-sensor. Owing to the excellent sensing performance, the sensing array was also fabricated. It is believed that this work develops a route for designing a self-powered sensor system with flexible production, high performance, and human-friendly characteristics for wearable electronics.

Capping-layer-mediated lattice mismatch and redox reaction in SrTiO3-based bilayers.

It is well known that the traditional two-dimensional electron system (2DES) hosted by the SrTiO3substrate can exhibit diverse electronic states by modifying the capping layer in heterostructures. However, such capping layer engineering is less studied in the SrTiO3-layer-carried 2DES (or bilayer 2DES), which is different from the traditional one on transport properties but more applicable to the thin-film devices. Here, several SrTiO3bilayers are fabricated by growing various crystalline and amorphous oxide capping layers on the epitaxial SrTiO3layers. For the crystalline bilayer 2DES, the monotonical reduction on the interfacial conductance, as well as carrier mobility, is recorded on increasing the lattice mismatch between the capping layers and epitaxial SrTiO3layer. The mobility edge raised by the interfacial disorders is highlighted in the crystalline bilayer 2DES. On the other hand, when increasing the concentration of Al with high oxygen affinity in the capping layer, the amorphous bilayer 2DES becomes more conductive accompanied by the enhanced carrier mobility but almost constant carrier density. This observation cannot be explained by the simple redox-reaction model, and the interfacial charge screening and band bending need to be considered. Moreover, when the capping oxide layers have the same chemical composition but with different forms, the crystalline 2DES with a large lattice mismatch is more insulating than its amorphous counterpart, and vice versa. Our results shed some light on understanding the different dominant role in forming the bilayer 2DES using crystalline and amorphous oxide capping layer, which may be applicable in designing other functional oxide interfaces.

Sedimentary record of silver in recent times from Chaohu Lake, East China, and its implications.

High-resolution record of silver (Ag) in lakes is indispensable for examining human impact on its deposition, and for understanding its geochemical cycling in the environment. However, such studies are extremely insufficient. In this study, a piston core (CHY) collected from the Chaohu Lake, east China, was analyzed to examine sedimentary history of Ag. A record of this metal in recent times was further reconstructed. The record displays significant changes. Prior to the 1960s, Ag concentrations stabilized at a relatively low level (0.06 ppm), but they increased rapidly (0.26 ppm) afterward. The average concentration of Ag in the profile is 0.13 ppm, higher than its crustal abundance. Enrichment factor (EF) analysis further reveals that Chaohu Lake was not polluted with Ag until the 1960s, but the pollution level increases rapidly since then, and now shows a moderate pollution. Sedimentary record of Ag closely follows population changes within the watershed, suggesting that human activity is possibly the ultimate driving factor for its distribution. Intensified industrial activities associated with population expansion may release silver to inflow rivers and Chaohu Lake, resulting in its ultimate settling down to the sediments. Sedimentary flux of Ag varies significantly between 42.9 and 392.0 µg/(m2·year), with an average of 236.8 µg/(m2·year). This is so far as we know the first high-resolution record of Ag and its flux in east China, providing new perspective for better understanding the distribution and transport of Ag in lake environment.

A "Pre-Division Metal Clusters" Strategy to Mediate Efficient Dual-Active Sites ORR Catalyst for Ultralong Rechargeable Zn-Air Battery.

To conquer the bottleneck of sluggish kinetics in cathodic oxygen reduction reaction (ORR) of metal-air batteries, catalysts with dual-active centers have stood out. Here, a "pre-division metal clusters" strategy is firstly conceived to fabricate a N,S-dual doped honeycomb-like carbon matrix inlaid with CoN4 sites and wrapped Co2 P nanoclusters as dual-active centers (Co2 P/CoN4 @NSC-500). A crystalline {CoII 2 } coordination cluster divided by periphery second organic layers is well-designed to realize delocalized dispersion before calcination. The optimal Co2 P/CoN4 @NSC-500 executes excellent 4e- ORR activity surpassing the benchmark Pt/C. Theoretical calculation results reveal that the CoN4 sites and Co2 P nanoclusters can synergistically quicken the formation of *OOH on Co sites. The rechargeable Zn-air battery (ZAB) assembled by Co2 P/CoN4 @NSC-500 delivers ultralong cycling stability over 1742 hours (3484 cycles) under 5 mA cm-2 and can light up a 2.4 V LED bulb for ≈264 hours, evidencing the promising practical application potentials in portable devices.

Ratiometric fluorescent sensing of phosphate ion in environmental water samples using flavin mononucleotide-functionalized Fe3O4 particles.

Phosphate ion (PO43-) serves as an important nutrient carrier to support the growth of aquatic animals and plants in aquatic systems. However, excess concentrations of PO43- are the key factor responsible for eutrophication, resulting in rapid deterioration of water quality. Therefore, accurate determination of PO43- is of great significance in water quality and security. In this study, flavin mononucleotide (FMN), an intracellular form of vitamin B2, was used as fluorophore. A novel "off-on" fluorescent sensing platform (FMN@Fe3O4) was fabricated for selective and sensitive detection of PO43-, and showed excellent fluorescence response and good selectivity for PO43- detection. With the addition of PO43-, the fluorescence intensity restored is proportional to PO43- concentration in the quantification range of 50 nM-0.75 µM with a limit of detection as low as 20 nM (0.62 µg.L-1, calculated by P element). An adsorption/desorption sensing mechanism via an in-depth analysis of the interfacial interaction between PO43- and FMN@Fe3O4 is proposed. FMN is first adsorbed by its terminal phosphate group on Fe3O4 particles to quench fluorescence. Free PO43- replaces the adsorbed FMN and restores the quenched fluorescence to achieve the aim of PO43- detection. In addition, this sensing system has been successfully validated in real water sample analysis and all reagents involved are nontoxic, environmentally benign, and easily-available. Therefore, this assay has great applicability in water quality monitoring.