Multiple Metal Research Articles

Synthesis of (TiyVzCr1-y-z)3C2Tx MXene for excellent electromagnetic wave absorption properties

MXenes are remarkable 2D materials for microwave absorption applications, with respect to physical and chemical properties. However, their elevated electrical conductivity and impedance mismatch results in a diminished microwave absorption rate. To overcome these issues, we have prepared TiVCrC2Tx and Ti0.5V2Cr0.5C2Tx MXenes using an element doping strategy. Thanks to their suitable dielectric constant, lattice distortion, and a large amount of defects caused by multiple transition metal atoms, results in an increase in polarization loss, enhanced impedance matching, and increased electromagnetic (EM) wave absorption capability. The experimental results showed that few-layer TiVCrC2Tx with a thickness of 3.19 mm and operating frequency as 6.88 GHz can achieve a minimum reflection loss (RLmin) of −57.8 dB. Additionally, it has an effective absorption bandwidth (EAB) of 2.88 GHz. On the other hand, few-layer Ti0.5V2Cr0.5C2Tx with a thickness of 1.95 mm and operating at a frequency of 10.72 GHz has an RLmin of −52.75 dB and an EAB of 1.44 GHz. The advantages of the element doping strategy in enhancing the microwave absorption performance of MXene are demonstrated by its excellent EM wave absorption capability, thin matching thickness, and low filling amounts of only 30 wt percent. These results suggest that doped MXene showed highly promising application in the field of EM wave absorption.

High-Entropy Selenides with Tunable Lattice Distortion as Efficient Electrocatalysts for Oxygen Evolution Reaction.

Developing stable and active electrocatalysts is crucial for enhancing the oxygen evolution reaction (OER) efficiency, which sluggish kinetics hinder sustainable hydrogen production. High entropy selenides (HESes) feature with random distribution of multiple metals cations and unique electronic and size effect of Se anion, allowing for precious regulation of their catalytic properties towards high OER activity. In this work, we report a series of high-entropy selenides catalysts with tunable lattice strain for electrocatalytic oxygen evolution. Electrochemical measurements show that the quinary (NiCoMnMoFe)Sex requires only 291 mV to reach 10 mA cm-2 and exhibits a superior stability with negligible current decay during 100 h's continuous operation. By combining experimental measurements and theoretical calculation, the study reveals that the lattice distortion, reflected by the local microstrain near the active site, plays a vital role in boosting the OER activity of HESes.

Relationship between exposure to multiple heavy metals and depressive symptoms in the US: The impact of alcohol consumption

Background/aimAlthough some heavy metals and alcohol consumption are known to have adverse effects on neurobehavioral symptoms, studies on the relationship between exposure to multiple metals and interaction between these factors are limited. In this study, we aimed to explore how multiple exposure to heavy metals with drinking habit in affecting depression using the National Health and Nutrition Examination Survey (NHANES) data. MethodsData from the U.S. NHANES between 2007 and 2014 were used to examine the cross-sectional relationships between heavy metal exposure and depression in adult over 20 years. After applying the exclusion criteria, 6021 subjects were included in the final analysis. We used four urinary metals, including mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As), as exposure variables. The Patient Health Questionnaire (PHQ-9) was used to assess the depression symptoms of the participants. Multivariate linear regression (MLR) and quantile g-computation models were applied to investigate the effects of individual and multiple heavy metal exposures on depression, respectively. We also performed stratified analysis according to the alcohol habit of the participants. ResultsThe MLR models revealed that urinary Cd was positively associated with a continuous depression score (β = 0.39, 95 % confidence interval (CI): 0.24–0.53). Meanwhile, other urinary metals showed an insignificant positive relationship with depression. In quantile g-computation model, statistically significant positive relationship was observed between urinary heavy metal mixture and depression score (difference in PHQ-9 score increase = 0.32, 95 % CI: 0.14–0.50). When the model was stratified by drinking habit, a stronger relationship was observed in the heavy drinker group. ConclusionsComparing the results from different models, both individual urinary Cd and all the heavy metal mixtures were positively associated with depression. This association was stronger among those with heavy drinking habits. Future cohort studies are needed to confirm these associations and to clarify the causal relationship.

Trace metal evolution of the Late Cretaceous Ocean

The Cenomanian-Turonian boundary (Late Cretaceous) witnessed the last spectacular manifestation of Mesozoic Anoxic Events (OAE 2, ∼94 Ma), marked by a prominent carbon isotope excursion (CIE) and burial of organic-matter-rich sediments under high atmospheric CO2 concentrations. But the Late Cretaceous generally was a time of profound environmental change. OAE 2 was preceded by other CIEs, including the Mid-Cenomanian Event (MCE), and was punctuated by a short re‑oxygenation and cooling event (the Plenus Cold Event, PCE). Extensive previous studies, including many trace metal studies, have focused on OAE 2, but there is still debate concerning the degree of drawdown of oceanic trace metal reservoirs during OAE 2, whether this drawdown is global or local, its causes and consequences for ocean ecology. Here, we present records of eight trace metals, over about 5 Myr of the Late Cretaceous, from the Tarfaya Basin in the proto-North Atlantic. The long records from a core preserving a continuous sedimentary succession allow us to set changes occurring across OAE 2 in the broader context of Late Cretaceous, including the lead up to OAE 2. Moreover, the multiple trace metal dataset allows us to broadly investigate the oceanographic setting in the context of recent studies of multiple trace metals in modern organic-rich sediments aimed at refining the proxies.Trace metal enrichments in these organic-rich sediments are discussed on three different timescales. Firstly, comparison of these Late Cretaceous sediments with modern organic-rich sediments are consistent with deposition in an open ocean upwelling margin in the Late Cretaceous, very like the modern Peru or Namibian Margin, although the deep proto-North Atlantic was probably partially restricted. Secondly, in common with previous studies, metal/TOC ratios often show sharp drops in the early part of OAE 2. Thirdly, however, this sharp drop occurs within a framework of pseudo-cyclical variations in metal/TOC, with a period of about 143 ±19 kyr (1 SD), that is a feature of these long records well before OAE 2, including across the MCE. Different metals respond differently to the perturbation in the early part of OAE 2 itself. Simple mass balance considerations suggest that trace metal drawdown with organic carbon must be at least partially compensated by changes in the rate of chemical weathering on the continents, as previously inferred from Li and Ca isotopes. Moreover, changes in the patterns of variation between different metals, as well as covariation of metal/TOC ratios and Os isotopes, hint at changes in the pattern of chemical weathering, most prominently in the contribution of mafic rocks to the chemical weathering flux.

Fe3O4 nanoparticles decorated on N-doped graphene oxide nanosheets for elimination of heavy metals from industrial wastewater and desulfurization

Finding an effective and excellent pertinent single catalyst material for multipurpose application for the purification of hydrocarbons in fuels (desulfurization), and for efficient removal of heavy metals from industrial effluent is greatly endowed. In the present work, a hybrid nanocomposite of ultrafine magnetite (Fe3O4) nanoparticle embedded on the surface of in-situ nitrogen doped layered GO (NGO) sheets were fabricated by sol-gel method and treatment with microwave irradiation technique is reported for the first time. The results show a high removal efficiency of 97 % for multiple heavy metals (Pb2+, Cd2+, Cu2+, Cr+2, Mn+2etc.) in industrial effluent and as well as in synthetic water with a very good retention performance of 99 %. The composites were tested against the elimination of sulfur from thiophene is 1.495 mmol g−1 is reported high is due to coupling and coordination of nitrogen with FeO and C. Recycling studies showed that the developed composites had excellent recyclability, with <82 % removal at the 5th cycle; its feasibility was evaluated using industrial effluent water and in synthetic water. Surface phenomena studies presented here revealed that the adsorptive removal processes of heavy metals involved π electron donor-acceptor interactions, ion exchange, and electrostatic interactions, along with surface complexation that showed an excellent synergism. A high stability, and retention performance is better than the pure Fe3O4 and NGO sheets. We hope that this study will motivate and give further scope for scientists working on magnetite-based graphene nanocomposites.

How Has the Source Apportionment of Heavy Metals in Soil and Water Evolved over the Past 20 Years? A Bibliometric Perspective

Exploring soil heavy metal sources is of great significance for ensuring the safety of ecological environments and agricultural product safety, as well as for guiding pollution control and management policies. This paper retrieved 452 research papers on soil heavy metal source analysis published over the 2004–2024 period from the Web of Science database. The collected literature was subjected to multidimensional bibliometric analysis using the CiteSpace 6.3.R1. The results showed significantly increasing trends in the scientific outputs and the number of papers on heavy metal source analysis in soils and water over the study period. In addition, related research topics have expanded from single to multiple heavy metal elements in environmental media and have increasingly recognized the impact of water pollution on soil contamination. Research methods have also evolved from basic statistical analysis to complex spatial analysis techniques, covering agricultural and urban soils. Previous related studies have focused on heavy metal pollution in different areas, and related research on heavy metal source analysis has now extended from ecological environments to associated human health risks. The present study provides directions for future related research and guidance for ensuring effective source control of heavy metal pollution and safe utilization of land and water resources.

Plasma Tailoring of NH2-MIL-53 with Enhanced Fluorescence Emission for Simultaneous Detection of Multiple Heavy Metals in Water.

Indium, copper, and mercury are important raw materials in the electronics industry and often coexist in factory wastewater. Therefore, the development of a highly sensitive and selective method for the simultaneous detection of these heavy metal ions is of great significance for water quality monitoring and environmental protection. Herein, we report a NH2-MIL-53 fluorescent probe for the simultaneous detection of trace In3+, Cu2+, and Hg2+ in water. After a low-temperature NH3 plasma tailoring treatment for grafting electron-donor amine groups, the obtained NH2-MIL-53-M exhibited enhanced fluorescence emission intensity (∼6 times) coupled with selective adsorption of In3+, Cu2+, and Hg2+. This quenched the NH2-MIL-53-M fluorescence and allowed to significantly increase the selectivity and sensitivity for detection of In3+, Cu2+, and Hg2+. The fluorescence quenching constant (Ksv) values were 2.23 × 105, 1.00 × 105, and 2.74 × 104 M-1, while the limit of detection (LODs) values were 0.06, 0.14, and 0.53 μM, for In3+, Cu2+, and Hg2+, respectively. The concentrations of In3+, Cu2+, and Hg2+ in real environmental samples could be determined by addition of appropriate masking agents, and the recoveries were within the range of 94-110%. This study not only supplied a strategy for constructing a highly sensitive and selective fluorescent probe but also established a platform for simultaneous detection of multiple heavy metal ions in water.

Tripartite Detection and Sensing of Toxic Heavy Metals Using a Copper-Based Porphyrin Metal-Organic Framework.

The detection of heavy metals in water sources is a critical concern for environmental preservation and public health. However, current electrochemical heavy metal sensors suffer from high sensing limits, cross-sensitivity, and poor selectivity. In this work, we present the possibility of an electrochemical sensor based on a copper (Cu) metal-organic framework for the detection of lead, cadmium, and mercury by replacing Cu metal nodes. The working electrode consists of a ∼5 μm thin layer of copper- tetracarboxyphenylporphyrin (Cu-TCPP) sheets that are adsorbed on a glassy carbon electrode (GCE). Upon interaction with Pb2+, Cd2+, and Hg2+, these ions are adsorbed on and incorporated into the metal nodes of the MOF. The adsorbed metallic species can be oxidized to the ionic form (Pb → Pb2+) electrochemically, which results in an oxidation response and enables the quantitative detection of these metals. The oxidation peak currents follow a (mostly) bimodal linear regression with a sensing range of up to 30 μM dependent on the deposition time and an ultralow limit of detection (LoD) of up to 5 nM. The system displays robust and selective sensing in saturated solutions of counterions and interfering metal ions (low error margins of <10%). This work represents the first report of a Cu-TCPP-modified GCE anode as an effective electrode for the sensitive detection of multiple heavy metals and an in-depth study into the Cu replacement kinetics of the Cu-MOF.

Macromineral, micromineral and metal concentration of bovine colostrum samples from Salzburg, Austria

BackgroundBesides immunoglobulins which are essential for the calf to prevent Failure of Transfer of Passive Immunity (FTPI) colostrum contains multiple other constituents such microminerals, macrominerals and metals. The concentration of the minerals seems to be higher in colostrum than in normal milk. The aims of this study were to describe macromineral, micromineral and metal concentration of bovine colostrum samples from Salzburg, Austria and to see if there are differences in the concentrations between different cow feeding strategies and farm locations. MethodsTherefore, 1050 individual colostrum samples were collected from 72 dairy farms from different districts of Salzburg. All colostrum samples were analysed for macromineral (K, Mg, Na), micromineral (Co, Cu, Fe, I, Mg, Se, Zn) andmetal (As, Ba, Cd, Li, Mo, Ni, Pb, Sr, Tl, U) concentrations by inductive coupled plasma mass spectrometry. ResultsThe mean K, Mg and Na levels were 1218.71 mg l-1, 245.44 mg l-1 and 358.62 mg l-1, respectively. The micromineral concentrations of I, Se, Co and Zn were significantly higher in colostrum from dairy cows feeding a Total-Mixed-Ration during the lactation period in comparison to cows receiving microminerals by hand feeding, transponder feeding or via a licking bucket or licking stone. The metal analysis showed that in three farms, most of the colostrum samples showed Pb levels above the limit of 5 µg l-1. ImplicationsHerd-level factors need to be addressed to elevate micromineral concentrations and to reduce metal concentrations in colostrum from dairy cows from Salzburg, Austria. ConclusionThe results show that the macrominerals K, Mg and Na are within the range of published concentrations. For the microminerals, Co, Cu, Fe, I, Mg, Se and Zn the concentrations were significantly different depending on the mineral feeding strategies during the lactation and dry period. Metal concentrations of As, Ba, Cd, Li, Mo, Ni, Pb, Sr, Tl and U differed between the districts of Salzburg.

A trans-translation inhibitor is potentiated by zinc and kills Mycobacterium tuberculosis and non-tuberculous mycobacteria.

Mycobacterium tuberculosis poses a serious challenge for human health, and new antibiotics with novel targets are needed. Here we demonstrate that an acylaminooxadiazole, MBX-4132, specifically inhibits the trans-translation ribosome rescue pathway to kill M. tuberculosis. Our data demonstrate that MBX-4132 is bactericidal against multiple pathogenic mycobacterial species and kills M. tuberculosis in macrophages. We also show that acylaminooxadiazole activity is antagonized by iron but is potentiated by zinc. Our transcriptomic data reveals dysregulation of multiple metal homeostasis pathways after exposure to MBX-4132. Furthermore, we see differential expression of genes related to zinc sensing and efflux when trans-translation is inhibited. Taken together, these data suggest that there is a link between disturbing intracellular metal levels and acylaminooxadiazole-mediated inhibition of trans-translation. These findings provide an important proof-of-concept that trans-translation is a promising antitubercular drug target.

Efficient removal of multiple heavy metal ions from wastewater using task-specific hydrophobic deep eutectic solvents: A circular approach

In this study, four hydrophobic deep eutectic solvents (HDESs) were prepared by combining lidocaine or ibuprofen with heptanoic acid in varying molar ratios for the efficient removal of heavy metal ions (HMIs) such as Cd(II), Pb(II), and Ni(II) from wastewater. The prepared HDESs were characterized using spectroscopic and thermal techniques, and their physicochemical properties, including density and viscosity, were investigated as a function of temperature. Liquid-liquid extraction (LLE) experiments were optimized for key parameters such as metal ion concentration, volume ratio, and pH. Among the HDESs, HDES1 (lidocaine-heptanoic acid in a 1:1 molar ratio) demonstrated superior extraction performance in both individual and mixed metal ion solutions, simulating real industrial conditions. Reusability studies of HDES1 showed consistent extraction performance over five consecutive cycles, indicating the sustainability of the process. The findings highlight the potential of HDES-based LLE for industrial applications, offering a cost-effective and environmentally friendly solution for HMI removal.

Polyaniline-coated sodium vanadate nanorods cathode boosting zinc ion dynamics in aqueous zinc-ion batteries

Aqueous zinc batteries (ZIBs) have recently emerged as a promising energy storage system due to their renewability, safety, and cost-effectiveness. However, its electrochemical kinetics are impeded by the issues of low Zn2+ diffusion efficiency and the facile growth of crystalline dendrites in the charging and discharging reactions, which present a significant challenge to the advancement of ZIBs. In this work, a polyaniline (PANI) coated sodium vanadate nanorod-like active material was designed to enhance the ion diffusion efficiency and reduce the tunneling structure collapse of sodium vanadate nanorods. This was achieved by increasing the specific surface area, enhancing the strength of the crystal structure, and introducing oxygen vacancies. The results demonstrated that the PANI-coated sodium vanadate nanorods exhibited stable and highly reversible electrochemical reactions during repeated insertion and extraction of zinc ions. The overall electrochemical performance of the PANI-coated sodium vanadate nanorod electrodes was markedly enhanced, exhibiting a high multiplicity performance of 141 mA/g at a current density of 2.0 A/g and a capacity retention rate of 99.83 % over 5000 cycles. The results provide some information for a better study of Zn2+ storage, as well as ideas for strategies for composite organic polymers with multiple heavy metal hybrid oxides.

Associations between co-exposure to multiple heavy metals and age-related macular degeneration: a cross-sectional study

Background & aimsAccumulating evidence suggests that exposure to single heavy metal can facilitate the progression of age-related macular degeneration (AMD). However, the effects of exposure to mixtures of heavy metals on AMD remain largely unexplored. This study aims to investigate both the joint and individual impacts of arsenic (As), mercury (Hg), cadmium (Cd), and lead (Pb) on AMD within a co-exposure framework. MethodsData from subjects participating the US National Health and Nutrition Examination Survey (NHANES, 2005-2008) were analyzed. Concentrations of As, Hg, Cd, and Pb were determined in urine by inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS) for As and Hg, and inductively coupled plasma mass spectrometry (ICP-MS) for Cd and Pb. The weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models were employed to assess the effects of heavy metal mixtures on AMD risk. ResultsBoth WQS and BKMR analyses consistently revealed a significant overall association between heavy metal mixtures and the risk of all types of AMD. The combined effect was more evident among patients with early AMD compared to those with late AMD. Cd and Hg were the main contributors driving these combined effects within the context of metal mixtures. Elevated urinary levels of Cd were positively correlated with an increased risk for all types as well as early AMD. Higher exposure to Hg corresponded with an elevated risk for early AMD. Furthermore, BKMR analysis indicated that the influence of Cd on early AMD exhibited a non-linear pattern. ConclusionsOur findings suggest that co-exposure to As, Hg, Cd, and Pb is associated with an elevated risk for developing AMD, particularly in its early stages. Furthermore, excessive exposure to Cd and Hg has been identified as key contributing factors in this process.

Eu-doped carbon dots-MOF based turn-on fluorescent probe for trace Hg2+ and Pb2+ and construction of the simultaneous detection model

Multiple trace heavy metal pollutants present a serious threat to the aquatic environment, and their coexistence also affected the detection efficiency. This work prepared Eu doped metal organic framework (MOF) complexed with S-containing carbon dots (CD(s)) exhibited dual-emission fluorescence. Its chelation-enhanced fluorescence with heavy metals replaced the original agglomerative fluorescence quenching of pure CD(s), which was utilized to construct a “turn on” fluorescence sensing probe. Based on the XPS, DFT and fluorescence lifetime results, the N, S functional groups on the surface of the materials could bind specifically to Hg2+ and Pb2+ with enhanced sensitivity. The limit of detection reached 76.67 nM for Hg2+ and 5.12 nM for Pb2+ within 2 min detection time. Furthermore, due to the different response mechanism of the two signal peaks to Hg2+ and Pb2+, a three-dimensional data model was developed for simultaneous detection in the co-existence system. The model had been successfully applied to actual Hg2+-Pb2+ containing water samples with recoveries ranged from 93.15 ∼ 105.08 %. The results provided a new strategy for simultaneous detection of trace environmental pollutants.

Interplay and long-lasting effects of maternal low-level Pb, Hg, and Cd exposures on offspring cognition

Lead (Pb), mercury (Hg), and cadmium (Cd) are prevalent and persistent environmental contaminants, causing detrimental effects on millions of individuals worldwide. Our previous research demonstrated that early-life exposure to low-level Pb, Hg, and Cd mixtures may lead to cognitive impairments. However, the association and interaction among low levels of Pb, Hg, or Cd exposure remains unclear. In this study, a two-level full factorial design (5.481, 0.036, and 2.132 mg/L for Pb, Hg, and Cd respectively) was conducted to assess the interplay among maternal Pb, Hg, and Cd exposure on offspring cognition. Following exposure during pregnancy and lactation, a competitive absorption among Pb, Hg, and Cd was observed. Maternal exposure to each metal alone resulted in higher blood and brain concentrations of Pb, Hg, and Cd in offspring compared to co-exposure at equivalent levels. However, behavioral experiments conducted in the Morris water maze and novel object recognition test revealed maternal Pb, Hg, and Cd exposure synergistically impaired offspring's spatial cognition and recognition memory. Importantly, this dysfunction persisted into middle age even without exposure after adulthood. Moreover, the open field test and elevated plus maze indicated maternal low-level Pb, Hg, and Cd co-exposure triggered risk-taking behavior in weaning offspring, with a significant main effect for Pb exposure. No long-lasting effect on risk-taking behavior was detected in middle-aged offspring. Further investigation into molecular mechanisms showed that the dysregulation of corticosterone reaction and immune response might be the potential mechanism underlying Pb, Hg, and Cd co-exposure-induced cognitive impairments. Our study highlights the synergistic and long-lasting effects of multiple heavy metal exposures,underscoring the urgency to prevent exposure to metal mixtures among children and women of childbearing age.

High-entropy sulfides enhancing adsorption and catalytic conversion of lithium polysulfides for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries with high energy density suffer from the soluble lithium polysulfide species. Traditional metal sulfides containing a single metal element used as electrocatalysts for Li-S batteries commonly have limited catalytic abilities to improve battery performance. Herein, based on the Hume-Rothery rule and solvothermal method, the high-entropy sulfide NiCoCuTiVSx derived from Co9S8 was designed and synthesized, to realize the combination of small local strain and excellent catalytic performance. With all five metal elements (Ni, Co, Cu, Ti, and V) capable of chemical interactions with soluble polysulfides, NiCoCuTiVSx exhibited strong chemical confinement of polysulfides and promoted fast kinetics for polysulfides conversion. Consequently, the S/NiCoCuTiVSx cathode can maintain a high discharge capacity of 968.9 mA h g−1 after 200 cycles at 0.5 C and its capacity retention is 1.3 times higher than that of S/Co9S8. The improved cycle stability can be attributed to the synergistic effect originating from the multiple metal elements, coupled with the reduced nucleation and activation barriers of Li2S. The present work opens a path to explore novel electrocatalyst materials based on high entropy materials for the achievement of advanced Li-S batteries.

Determining bad actors: A linear mixed effects model approach to elucidate behavioral toxicity of metal mixtures in drinking water

Mixtures of chemical contaminants can pose a significant health risk to humans and wildlife, even at levels considered safe for each individual chemical. There is a critical need to develop statistical methods to evaluate the drivers of toxic effects in chemical mixtures (i.e., bad actors) from exposure studies. Here, we develop a hierarchical modeling framework to disentangle the toxicity of complex metal mixtures from a screening study of 92 drinking well water samples containing multiple metal elements from Maine and New Hampshire, USA. In order to screen for neurodevelopmental impacts from exposure to these drinking water samples, we use a larval zebrafish (Danio rerio) behavioral assay. Zebrafish are an advantageous toxicological model organism due to combining the complexity of a vertebrate organism and higher-throughput exposure methods. We formulate a linear mixed modeling approach that captures intrinsic complexity in a common larval behavioral assay in order to improve its sensitivity and rigor and identify drivers of behavioral toxicity from the metal mixtures within the drinking water samples. Our analysis identifies lead (Pb), cadmium (Cd), nickel (Ni), copper (Cu), barium (Ba), and uranium (U) as metals that consistently impact larval locomotor activity, individually and across nine pairs of those metals. Our model also elucidates three distinct clusters of metal mixture components that drive behavioral effects: (Ba:Cu:U), (Ni:Pb:U), (Ba:Pb:U). Having identified a set of “bad-actor” metals from the water samples, we conduct exposure experiments for each individual metal (Pb, Cd, Ni, Cu, and Ba) at levels considered safe by the US Environmental Protection Agency drinking water regulatory limits and validate Pb, Ni, Cu, and Ba as behavioral toxicants at these concentrations. Collectively, our modeling approach estimates the impact of metal elements on a complex behavioral outcome in a statistically robust manner and establishes an approach to capture “bad actors” and key chemical interactions in a complex mixture.

Associations of mixed metals exposure with cognitive impairment risk: a cross-sectional study in Chinese adults.

Associations between exposure to single metals and cognitive impairment or related outcomes have been reported in many previous studies. However, co-exposure to more than one metal is common situation. In recent years, studies on the effects of exposure to multiple metals on cognitive impairment or related outcomes have increased, but remain very limited, with a focus on populations with occupational exposure to metals, children, and adolescents. The potential relationships between exposure to metal mixtures and risk of cognitive impairment in adults remain to be clarified. To determine the associations between blood metal mixtures and cognitive impairment risk. Inductively coupled plasma mass spectrometry (ICP-MS) was utilized to detect the blood levels of lead (Pb), iron (Fe), copper (Cu), calcium (Ca), magnesium (Mg), and zinc (Zn). Multivariable logistic regression and Bayesian kernel machine regression (BKMR) models were employed to assess the relationships of exposure to these blood metal mixtures with the risk of cognitive impairment. It was found that four metals (Pb, Fe, Cu, and Mg) were positively correlated with cognitive impairment in each single metal model. The association of Pb and Cu remained significant after adjusting for these six metals, with the odds ratios (95% confidence intervals) in the highest quartiles of 9.51 (4.41-20.54, p-trend <0.01) and 4.87 (2.17-10.95, p-trend <0.01), respectively. The BKMR models indicated that co-exposure levels of Ca, Cu, Fe, Mg, Pb, and Zn were related to increased risk of cognitive impairment at ≥25th percentile compared with median, and Pb and Cu mainly contributed to the joint effect. In addition, the interaction effects of Mg and Pb/Pb and Cu on the risk of cognitive impairment were observed. Co-exposure of six metals (Pb, Fe, Cu, Ca, Mg, and Zn) increased the risk of cognitive impairment in Chinese adults, with Pb and Cu likely to have greater impact. Potential interaction effects of Mg and Pb, Pb and Cu on the risk of cognitive impairment may exist.

Design and demonstration of a temperature-resistant aptamer structure for highly sensitive mercury ion detection with BioFETs

In this study, we developed a temperature-resistant aptamer coupled with extended gate electric double-layer Field-Effect Transistors (FETs) for highly sensitive mercury ion detection. The design of the temperature-resistant aptamer is based on the thermal and structural properties of the hairpin structure. Two aptamer sequences were designed with different melting temperatures (Tm) and compared for their sensitivity. The hairpin structure of the aptamer with a high melting temperature ensures the stable structure prior to the addition of the mercury ions, which allows the formation of thymine–mercury–thymine (T -Hg2+-T) complex in low concentrations of mercury ions. High sensitivity and low detection limit are achieved at elevated temperatures with the aptamer having a high melting temperature. The elevated temperature facilitates the reaction rate, resulting in high sensitivity and a low detection limit. The aptamer with a high melting temperature hairpin structure has shown a remarkable improvement in the limit of detection with a 4 orders of magnitude increase compared to the one with a low melting temperature. The sensor with the high melting temperature aptamer shows an extremely low detection limit of 4.68 × 10−12 M, surpassing previously reported results. The aptamer with a low melting temperature requires mercury ions to stabilize the hairpin structure by forming a T-Hg2+-T complex. The results show that if the melting temperature is lower than the ambient temperature, it is very difficult to detect low concentrations of mercury ions at the ambient temperature. The selectivity of this sequence was also tested against multiple heavy metals, including arsenic (As), lead (Pb), chromium (Cr), and cadmium (Cd) ions. This study has shown how the structural and thermal properties of the aptamer, and the ambient temperature affect the sensitivity. They are strongly correlated to the performance of the sensors and need to be considered in the design of the sequence.

Dynamic Rare-Earth Metal-Organic Frameworks Based on Molecular Rotor Linkers with Efficient Emissions and Ultrasensitive Optical Sensing Performance.

4,4',4″-Triphenylamine tricarboxylate (TPA-COOH) with a distinct molecular rotor structure was reacted with rare-earth (RE) metal ions to obtain seven dynamic RE-based luminescent MOFs (RE-LMOFs) (i.e., emission colors in the blue, yellow-green, red, and near-infrared regions and emission peak wavelengths between 400 and 1600 nm) via the effective transfer of absorbed energy from TPA-COOH to the RE metal ions through the antenna effect. Due to the large energy level difference between RE ions, it was rare in the early days to use the same ligand to construct energy-level matching RE-LMOF homologues with multiple RE metal centers. The uncoordinated oxygen atoms on the molecular rotor linkers in RE-LMOFs provide active sites that can specifically capture highly toxic metal ions and strong oxidative pollutants. The limit of detection (LOD) of RE-LMOF for Al(III) ions is far below the maximum concentration of Al(III) ions in drinking water stipulated by the U.S. Environmental Protection Agency (USEPA) and that for H2O2 is much lower than the H2O2 content in cancer cells, showing excellent application potential for diagnosing early cell cancelation.