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For rooting the development of GaN-based optoelectronic devices, understanding the roles of midgap recombination centers (MGRCs), namely, nonradiative recombination centers and deep-state radiative recombination centers, on the carrier recombination dynamics is an essential task. By using the combination of time-resolved photoluminescence and positron annihilation spectroscopy (PAS) measurements, the origins of major MGRCs in the state-of-the-art GaN epilayers, bulk crystals, and Mg-implanted layers were identified, and their concentrations were quantified for deriving the capture coefficients of minority carriers. In this article, potential standardization of the room-temperature photoluminescence lifetime for the near-band-edge emission (τ PL RT ) as the concentration of major MGRCs well below the detection limit of PAS is proposed. For n-GaN substrates and epilayers grown from the vapor phase, τ PL RT was limited by the concentration of carbon on N sites or divacancies comprising a Ga vacancy (VGa) and a N vacancy (VN), [VGaVN], when carbon concentration was higher or lower, respectively, than approximately 1016 cm−3. Here, carbon and VGaVN act as major deep-state radiative and nonradiative recombination centers, respectively, while major MGRCs in bulk GaN crystals were identified as VGa(VN)3 vacancy clusters in Na-flux GaN and VGa or VGaVN buried by a hydrogen and/or VGa decorated with oxygen on N sites, VGa(ON)3–4, in ammonothermal GaN. The values of τ PL RT in n-GaN samples are compared with those of p-GaN, in which τ PL RT was limited by the concentration of VGa(VN)2 in Mg-doped epilayers and by the concentrations of VGaVN and (VGaVN)3 in Mg-implanted GaN right after the implantation and after appropriate activation annealing, respectively. [ABSTRACT FROM AUTHOR]

The Zeno line is the locus of points on the temperature–density plane where the compressibility factor of the fluid is equal to one. It has been observed to be straight for a broad variety of real fluids, although the underlying reasons for this are still unclear. In this work, a detailed study of the Zeno line and its relation to the vapor–liquid coexistence curve is performed for two simple model pair-potential fluids: attractive square-well fluids with varying well-widths λ and Mie n-6 fluids with different repulsive exponents n. Interestingly, the Zeno lines of these fluids are curved, regardless of the value of λ or n. We find that for square-well fluids, λ ≈ 1.8 presents a Zeno line, which is the most linear over the largest temperature range. For Mie n-6 fluids, we find that the straightest Zeno line occurs for n between 8 and 10. Additionally, the square-well and Mie fluids with the straightest Zeno line showed the closest quantitative agreement with the vapor–liquid coexistence curve for experimental fluids that follow the principle of corresponding states (e.g., argon, xenon, krypton, methane, nitrogen, and oxygen). These results suggest that the Zeno line can provide a useful additional feature, in complement to other properties, such as the phase envelope, to evaluate molecular models. [ABSTRACT FROM AUTHOR]

Author affiliations *Corresponding authors n this work, a highly sensitive procedure for the determination of mercury in flue gas was developed, based on direct-current atmospheric pressure glow discharge in hydrogen and helium (H2-He) atomic emission spectroscopy (APGD-AES) coupled with gold amalgam enrichment (GA). Calibration mercury vapors generated by the cold vapor generation (CVG) system were sent to the GA system for enrichment. Subsequently, mercury was thermally desorbed and transmitted to APGD for excitation, and at the same time, the signal at 253.6 nm was recorded using a micro-spectrometer. The parameters of GA and APGD systems were optimized, including the type and flow rate of the carrier gas, discharge current and discharge gap. Under the optimum operating conditions, when the sampling volume of the flue gas was 10 L, the detection limit (DL) of Hg was 0.1 μg m-3, which met the actual measurement requirements, and the relative standard deviation (RSD) was 2% (n = 11), the linear correlation coefficient was better than 0.999. The accuracy and practicality of GA-APGD-AES were verified by the analysis of flue gas. The results were consistent with those of a direct mercury analysis (DMA) system (n = 3, relative deviation was less than 3%). [ABSTRACT FROM AUTHOR]

Because of the hazards associated with handling mercury, most standards organizations have withdrawn the conventional mercury (displacement) method (MM) for shrinkage limit (SL) determination of fine-grained soils. Despite attempts to substantiate the wax (coating) method (WM), which is presently the only standardized MM-testing alternative, the geotechnical community remains somewhat hesitant of its adoption in routine practice. To encourage more widespread use of WM-testing, this study re-examines the level of agreement between the MM- and WM-deduced SL parameters (i.e., SLMM and SLWM, respectively). This was achieved by performing comprehensive statistical analyses on the largest and most diverse database of its kind, to date, entailing SLMM:SLWM measurements for 168 different fine-grained soils having wide ranges of plasticity characteristics (i.e., liquid limit = 31.6–362.0%, plasticity index = 8.2–318.0% and SLMM = 7.1–42.0%). Furthermore, an attempt was made to evaluate the SLWM (in lieu of the SLMM) parameter for performing preliminary soil expansivity assessments using existing SLMM-based classification approaches. It was demonstrated that the MM and WM methods do not produce identical SL values for a given fine-grained soil under similar testing conditions, with their discrepancy being systematic and hence likely arising from the differences between the materials (mercury versus wax) and methodologies involved in performing these tests. New SLWM → SLMM conversion relationships were established, allowing SLMM to be deduced as a function of SLWM with high accuracy. Hence, when inputting SLWM in SLMM-based empirical correlations to predict other geoengineering design parameters, the newly proposed conversion relationships can be employed to minimize systematic prediction errors. It was also demonstrated that plasticity-based correlations, at best, can only provide a rough approximation of SLMM. Hence, when the SL is desired, WM-testing or any other alternative method that directly and reliably measures the soil shrinkage factors should be retained. Finally, the same soil-expansivity rankings, as obtained for existing classification systems employing SLMM results, are achieved using SLWM measurements (i.e., without the need of applying SLWM → SLMM conversion equations). [ABSTRACT FROM AUTHOR]

Mercury emissions from human activities persist in the environment, posing risks to humans and ecosystem, and are regulated by the Minamata Convention. Understanding the historical emissions of mercury is critical for explaining the presence of mercury in the environment. In recent years, some studies have looked at the historical trends of atmospheric emission inventory. The spatial resolution of inventories for relatively recent years have improved. However, limited inventories have combined both long time scales and high spatial resolution, which is essential for evaluating the legacy impacts of anthropogenic mercury emissions, particularly in regions with high levels of mercury emissions. Here we compile a new comprehensive point source database by fusing multiple data source, and integrate it with previous China Atmospheric Mercury Emission Model to create an annual point source and gridded emission inventory for China covering 1978–2021. Integrating point source emission inventory (P-CAME) improves the accuracy of the gridded emissions, reducing the normalized mean error for all grids by 108 % compared to not using point sources in the most recent year of 2021. The improved gridded emissions inventory notably enhances the simulation of atmospheric mercury concentrations, particularly in urban areas. P-CAME inventory resulted in a 20–23 % reduction in the normalized mean bias. The improved gridded emission data identifies potential polluted grids characterized by high cumulative emissions. It indicates that 20 % of cumulative emissions originate from just 0.3 % of the grids, primarily distributed in Gansu, Yunnan, and Hunan Provinces. These areas are predominantly dominated by non-ferrous metal smelters or a mix of emissions sources including coal-fired industries and cement production. With the improvements in simulation accuracy and the identification of highly polluted regions, this updated inventory would greatly facilitate the assessment of mercury exposure, legacy impacts, and effective management of cross-media mercury pollution. [ABSTRACT FROM AUTHOR]

Background: Mercury (Hg) is highly toxic and has the potential to cause severe health problems for humans and foraging animals when transported into edible plant parts. Soil rhizobia that form symbiosis with legumes may possess mechanisms to prevent heavy metal translocation from roots to shoots in plants by exporting metals from nodules or compartmentalizing metal ions inside nodules. Horizontal gene transfer has potential to confer immediate de novo adaptations to stress. We used comparative genomics of high quality de novo assemblies to identify structural differences in the genomes of nitrogen-fixing rhizobia that were isolated from a mercury (Hg) mine site that show high variation in their tolerance to Hg. Results: Our analyses identified multiple structurally conserved merA homologs in the genomes of Sinorhizobium medicae and Rhizobium leguminosarum but only the strains that possessed a Mer operon exhibited 10-fold increased tolerance to Hg. RNAseq analysis revealed nearly all genes in the Mer operon were significantly up-regulated in response to Hg stress in free-living conditions and in nodules. In both free-living and nodule environments, we found the Hg-tolerant strains with a Mer operon exhibited the fewest number of differentially expressed genes (DEGs) in the genome, indicating a rapid and efficient detoxification of Hg from the cells that reduced general stress responses to the Hg-treatment. Expression changes in S. medicae while in bacteroids showed that both rhizobia strain and host-plant tolerance affected the number of DEGs. Aside from Mer operon genes, nif genes which are involved in nitrogenase activity in S. medicae showed significant up-regulation in the most Hg-tolerant strain while inside the most Hg-accumulating host-plant. Transfer of a plasmid containing the Mer operon from the most tolerant strain to low-tolerant strains resulted in an immediate increase in Hg tolerance, indicating that the Mer operon is able to confer hyper tolerance to Hg. Conclusions: Mer operons have not been previously reported in nitrogen-fixing rhizobia. This study demonstrates a pivotal role of the Mer operon in effective mercury detoxification and hypertolerance in nitrogen-fixing rhizobia. This finding has major implications not only for soil bioremediation, but also host plants growing in mercury contaminated soils. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have contributed to the increase of heavy metals and to the alteration of their natural cycles in the environment. Mercury (Hg) is now considered to be one of the most toxic elements whose levels need to be monitored in abiogenic and biogenic environmental compartments. It can enter the body of animal in several ways, mainly through contaminated food. In this study, we compared mercury levels in mouse hair and songbird feathers from Zhongar Alatau National Park in Kazakhstan and from national parks in Slovakia. We sampled mice of the genus Apodemus and songbirds of three genera – Parus, Phylloscopus and Turdus. Total mercury concentrations were measured using DMA-80. The results showed higher levels of Hg bioaccumulation in Slovakia than in Kazakhstan in both songbirds and mice. The three songbird species from Kazakhstan showed differences due to different feeding niches. High levels were found in thrushes, which are considered insectivorous ground feeders, whereas the lowest mercury concentrations were detected in tits, which are considered more generalist feeders. In Slovakia, the trend was different, with tits having similar levels of Hg to thrushes, a reflection of the different levels of contamination of environmental components. Mice showed overall lower concentrations than birds at both sites. [ABSTRACT FROM AUTHOR]

Guizhou province is the most abundant region of mercury resources in China. The long history of mining activities has resulted in severe mercury (Hg) pollution and endangering both environment and human health. This study investigated the impact of different fertilizers on Hg-polluted soil bacterial community structure. We assumed that (1) fertilizer application would lead to changes in the bacterial community; and (2) the combined application of two fertilizers did not cause additive effects. The results revealed the application of bio-organic fertilizer could significantly enhance the bacterial community diversity. However, the combination of multiple fertilizers did not yield synergistic effects. There were indications of antagonistic interactions between certain fertilizers via competition or inhibitory effects. Additionally, we conducted an experiment in the greenhouse with Brassica Pekinensis and the Hg contents in roots and leaves were measured. Our findings suggested that different fertilizers would change the release fluxes of soil Hg(0). By immobilization of Hg in the soil, fertilizer could promote a healthier and more diverse soil bacterial community. This study provides valuable insights into the influence of different fertilizers on bacterial community in Hg-polluted soil, offering potential directions for further remediation efforts and policies. [ABSTRACT FROM AUTHOR]

Soil contamination by toxic metals threatens global public health, highlighting the need for cost-effective and ecologically sound site remediation. In this study, we assessed phytoremediation of Hg-contaminated soils by Emilia fosbergii Nicolson (Asteraceae). Pot experiment was conducted using a substrate of sand and vermiculite (1:1 volume ratio), treatments consisted of five Hg concentrations (0, 1, 3, 5, and 7 mg kg−1). Metal transfer rates were calculated, including accumulation (BAF), translocation (TF) and bioconcentration (BCF) factors. E. fosbergii roots exhibited greater Hg accumulation than other tissues, but biomass production and plant health were not significantly affected at the concentrations tested, as indicated by elongation factors and tolerance index. The results revealed BAF values between 2.18 and 7.14, TF values ranged between 0.15 and 0.52, and the BCF index varied between 8.97 and 26.58. Treatments with Hg content of 5 mg kg−1 and 7 mg kg−1 recorded the highest total Hg concentrations of 66 mg kg−1 and 65.53 mg kg−1 (roots), and 9.18 mg kg−1 and 33.88 mg kg−1 (aerial), respectively. E. fosbergii demonstrated promise for Hg phytoremediation due to its high accumulation capacity, indicated by regular TF and high BCF and BAF indexes, thus classifying it as a high Hg accumulator. Phytoextractor and phytostabilizer plant, high accumulator of Hg. Weed with great capacity for proliferation and adaptability. E. fosbergii showed tolerance to Hg in the substrate. Promising plant for phytoremediation of soils contaminated by Hg. Novel species for recovery of soils degraded by Hg exposure. [ABSTRACT FROM AUTHOR]

Anthropogenic mercury (Hg) emissions to the atmosphere are a long-lived hazard to human and environmental health. The UN Minamata Convention on Mercury is seeking to lower anthropogenic mercury emissions through a mix of policies from banning certain Hg uses to reducing unintentional Hg release from different activities. In addition to independent Hg policy, strategies to mitigate greenhouse gases, particulate matter (PM) and SO2 may also lower Hg emissions as a co-benefit. This study uses the Greenhouse Gas–Air Pollution Interactions and Synergies (GAINS) model to examine the effect of different clean air and climate policies on future global Hg emissions. The baseline scenario assumes current trends for energy use and Hg emissions as well as current legislation for clean air, mercury and climate policy. In addition, we explore the impact of the Minamata Convention, the co-benefits of climate and stringent air pollution policies, and maximum feasible reduction measures for Hg. Hg emission projections until 2050 show noticeable reductions in combustion sectors for all scenarios due to a decrease in global fossil fuel and traditional biomass use, leading to emission reductions of 33 % at baseline and up to 90 % when combining stringent climate controls and the most efficient Hg controls. Cement and non-ferrous metal emissions increase in all scenarios with current air pollution policy but could be reduced by up to 72 % and 46 %, respectively, in 2050 with stringent Hg -specific measures. Other emissions (including waste) are a significant source of uncertainty in this study, and their projections range between a 22 % increase and a 54 % decrease in 2050, depending on both climate and clean air policy. The largest absolute reduction potential for Hg abatement but also the largest uncertainties regarding absolute emissions lie in small-scale and artisanal gold production, where abatement measures could eliminate annual Hg emissions in the range of 601–1371 t (95 % confidence interval), although the uncertainties in the estimate are so high that they might eclipse reduction efforts in all other sectors. In total, 90 % of Hg emissions are covered by provisions of the Minamata Convention. Overall, the findings emphasize the necessity to implement targeted Hg control policies in addition to stringent climate, PM and SO2 policies to achieve significant reductions in Hg emissions. [ABSTRACT FROM AUTHOR]

Bimetallic compounds containing direct metal‐group 13 element bonds have been shown to display unprecedented patterns of cooperative reactivity towards small molecules, which can be influenced by the identity of the group 13 element. In this context, we present here a systematic appraisal of group 13 metallo‐ligands of the type [(NON)E]− (NON=4,5‐bis(2,6‐diisopropylanilido)‐2,7‐di‐tert‐butyl‐9,9‐dimethylxanthene) for E=Al, Ga and In, through a comparison of structural and spectroscopic parameters associated with the trans L or X ligands in linear d10 complexes of the types LM{E(NON)} and XM′{E(NON)}. These studies are facilitated by convenient syntheses (from the In(I) precursor, InCp) of the potassium indyl species [{K(NON)In}⋅KCp]n (1) and [(18‐crown‐6)2K2Cp] [(NON)In] (1′), and lead to the first structural characterisation of Ag−In and Hg−E (E=Al, In) covalent bonds. The resulting structural, spectroscopic and quantum chemical probes of Ag/Hg complexes are consistent with markedly stronger σ‐donor capabilities of the aluminyl ligand, [(NON)Al]−, over its gallium and indium counterparts. [ABSTRACT FROM AUTHOR]

This paper represents the reviews of recent advancements in different physicochemical methods for disinfecting contaminated surfaces, which are considered to be responsible for transmitting different bacterial, viral, and fungal infectious diseases. Surface disinfection can be achieved by applying chemicals, UV-based processes, ionization radiation (gamma-ray, X-ray and electron beam), application of self-disinfecting surfaces, no-touch room disinfection methods, and robotic disinfection methods for built-in settings. Application of different chemicals, such as alcohols, hydrogen peroxide, peracetic acid, quaternary ammonium salts, phenol, and iodine solution, are common and economical. However, the process is time-consuming and less efficient. The use of UVC light (wavelength: 200–280 nm, generated by low vapor mercury lamps or pulse xenon light) has gained much attention for disinfecting fomites worldwide. In recent times, the combination of UV and H2O2, based on the principle of the advanced oxidation process, has been applied for disinfecting inanimate surfaces. The process is very efficient and faster than chemical and UV processes. Heavy metals like copper, silver, zinc, and other metals can inactivate microbes and are used for surface modification to produce self-disinfecting surfaces and used in healthcare facilities. In combination with UVB (280–315 nm) and UVA (315–400 nm), titanium oxide has been utilized for disinfecting contaminated surfaces. Ionization radiation, one of the advanced methods, can be used in disinfecting medical devices and drugs. Post-COVID-19 pandemic, the no-touch and robotic disinfection methods utilizing chemicals or UVC lights have received much importance in built-in settings. Among these methods, surface disinfection by applying chemicals by fogging/vaporization and UV radiation methods has been widely reported in the literature compared to other methods. [ABSTRACT FROM AUTHOR]

Despite being acknowledged as an air pollutant, heavy metal contaminants in the atmosphere are not yet well studied in the Philippines. This study aims to assess the particulate matter, as well as mercury and lead concentration, in Metro Manila's ambient atmosphere. A one-hour sampling period was used to collect data at seven sampling stations using a respirable dust sampler with a flow rate of 1.4 m³/min. The mercury concentration was determined using cold vapor atomic absorption spectroscopy, whereas lead concentrations were measured using flame atomic absorption spectroscopy. Taguig had the highest level of total suspended particulates (TSP) at 524.07 µg/NCM, followed by Caloocan (459.92 µg/NCM) and Quezon City (434.50 µg/ NCM). Parañaque reported moderate particulate levels -- recorded at 298.95, 291.69, and 347.36 µg/NCM, respectively. Valenzuela had the lowest TSP level at 263.85 µg/NCM. Results show that mercury concentrations were highest in the City of Manila with 0.09 µg/m³, followed by Valenzuela City with 0.009 µg/m³, against the lowest concentration in Taguig City and Quezon City with 0.001 µg/m³. However, based on the legal airborne permissible exposure from the Philippine Occupational Safety and Health Standards, the mercury concentration in the seven cities of Metro Manila did not exceed its 0.5 mg/m³ (50 µg/m³) limit. Furthermore, results revealed that atmospheric lead concentration in Metro Manila existed only in trace amounts (≤ limit of detection). The high concentration of mercury in the City of Manila could be attributed to its high population density combined with massive industrial, commercial, and transport activities. Monitoring the concentration of heavy metals in the atmosphere is critical for the development of effective strategies for reducing the negative impacts of these global pollutants. [ABSTRACT FROM AUTHOR]

The identification of trace element anomalies in soils has been proven to assist semi-mechanized small-scale gold operations. This study employs soil geochemistry combined with the microchemical signature of particulate gold from the Batouri goldfield to (1) vector possible gold-endowed lithologies introducing particulate gold into the overlying regolith, and (2) assess anthropogenic Hg used in purification of both primary and alluvial/eluvial gold by artisans. The soil geochemistry shows irregularly distributed anomalies of elevated Cu especially in the saprolite soil layer. Whereas in the lateritic soil layer, a Au-Ag-Hg metal association is reported for the first time in this gold district and could be linked to anthropogenic Hg used in gold recovery. Particulate gold recovered from the soil varies in shape from euhedral and irregular to sub-rounded, indicating a proximal lode source. The gold grains range in size from nano-particles to >300 µm and are Au-Ag alloys. The gold particles reveal inclusions such as quartz, silicate, zircon and ilmenite suggesting that the grains were dislodged from quartz veins within the granitic basement. Systematic variation in the microchemical signature of the gold grains is suggestive of spatial and temporal evolution of the mineralizing fluid. These results are consistent with investigations from similar geologic settings worldwide and validate the combined utility of gold fingerprinting and pathfinder elements in soil to examine deposit genesis in other gold districts globally. [ABSTRACT FROM AUTHOR]

Developing convenient and reliable methods for Hg2+ monitoring is highly important. Some precious metal nanomaterials with intriguing peroxidase-like activity have been used for highly sensitive Hg2+ detection. However, H2O2 must be added during these detections, which impedes practical applications of Hg2+ sensors due to its susceptible decomposition by environmental factors. Herein, we discovered that the combination of Hg2+ and palladium metal-organic framework@graphene (Pd-MOF@GNs) exhibits oxidase-like activity (OXD). In the absence of H2O2, this activity not only catalyzes the oxidation of chromogenic substrates such as 3,3',5,5'-tetramethylbenzidine (TMB) or o-phenylenediamine (OPD) to produce a color change but also enhances the electrical signals during OPD oxidation. Based on these properties, an effective and convenient dual-mode colorimetric and electrochemical sensor for Hg2+ has been developed. The colorimetric and amperometric linear relationships for Hg2+ were 0.045 μM—0.25 mM and 0.020 μM—2.0 mM, respectively. The proposed strategy shows good recovery in real sample tests, indicating promising prospects for multiple environmental sample detection of Hg2+ without relying on H2O2. The colorimetric and electrochemical dual-mode Hg2+ sensor is expected to hold great potentials in applications such as environmental monitoring, rapid field detection, and integration into smartphone detection of Hg2+. [ABSTRACT FROM AUTHOR]

We present OpenPFC (https://github.com/VTT-ProperTune/OpenPFC), a state-of-the-art phase field crystal (PFC) simulation platform designed to be scalable for massive high-performance computation environments. OpenPFC can efficiently handle large-scale simulations, as demonstrated by our strong and weak scaling analyses up to an 81923 grid on 65 536 cores. Our results indicate that meaningful PFC simulations can be conducted on grids of size 20483 or even 40963, provided there is a sufficient number of cores and ample disk storage available. In addition, we introduce an efficient implementation of moving boundary conditions that eliminates the need for copying field values between MPI processes or adding an advection term to the evolution equations. This scheme enhances the computational efficiency in simulating large scale processes such as long directional solidification. To showcase the robustness of OpenPFC, we apply it to simulations of rapid solidification in the regime of metal additive manufacturing using a recently developed quantitative solid-liquid-vapor PFC model, parametrized for pure tungsten (body-centered cubic) and aluminum (face-centered cubic). [ABSTRACT FROM AUTHOR]

The subcontinental lithospheric mantle (SCLM) is now suggested by many workers to play a role in the formation of orogenic gold deposits in active continental margins, given that the gold and volatiles may be introduced into the SCLM during plate subduction. The giant Cretaceous Jiaodong gold province within the North China block occurs in a convergent margin setting where there is no terrane accretion, thus eliminating from consideration the commonly accepted metal and fluid source reservoir for orogenic gold--the metamorphosed upper crust of an active orogenic belt. Thus, the auriferous fluids were released below the high-grade Archean cratonic rocks from either enriched SCLM or directly from the subducted oceanic slab. Mercury (Hg) isotopes allow fingerprinting of isotopically distinct reservoirs, discriminating between the two possibilities. We present Hg isotope data for a set of pyrite grains, native gold, and lamprophyres from six main gold districts in the Jiaodong gold province. These samples dominantly yielded near-zero Δ199Hg (0‰ ± 0.1‰), within uncertainty of the mantle Δ199Hg value. The results provide novel evidence that the SCLM predominantly controlled the Hg budget of the Jiaodong gold deposits, implying that the SCLM acted as a buffer for the crustal mass-independent fractionation Hg signatures and a storage reservoir for gold and volatiles. Consequently, during slab subduction, gold and volatiles were recycled and stored within the SCLM and were later released from the mantle during uplift and relaxation of compressional tectonics. [ABSTRACT FROM AUTHOR]

Background: The global burden of chronic diseases has been increasing, with evidence suggesting that diet and exposure to environmental pollutants, such as per- and polyfluoroalkyl substances (PFAS) and heavy metals, may contribute to their development. The Dietary Inflammatory Index (DII) assesses the inflammatory potential of an individual's diet. However, the complex interplay between PFAS, heavy metals, and DII remains largely unexplored. Objective: The goal of this cross-sectional study was to investigate the associations between diet operationalized as the DII with individual and combined lead, cadmium, mercury, perfluorooctanoic acid (PFOA), and perfluorooctanesulfonic acid (PFOS) exposures using data from the National Health and Nutrition Examination Survey (NHANES) 2017–2018. Methods: Descriptive statistics, a correlational analysis, and linear regression were initially used to assess the relationship between the variables of interest. We subsequently employed Bayesian kernel Machine regression (BKMR) to analyze the data to assess the non-linear, non-additive, exposure–response relationships and interactions between PFAS and metals with the DII. Results: The multi-variable linear regression revealed significant associations between the DII and cadmium and mercury. Our BKMR analysis revealed a complex relationship between PFAS, metal exposures, and the DII. In our univariate exposure–response function plot, cadmium and mercury exhibited a positive and negative linear relationship, respectively, which indicated a positive and negative relationship across the spectrum of exposures with the DII. In addition, the bivariate exposure–response function between two exposures in a mixture revealed that cadmium had a robust positive relationship with the DII for different quantiles of lead, mercury, PFOA, and PFOS, indicating that increasing levels of cadmium are associated with the DII. Mercury's bivariate plot demonstrated a negative relationship across all quantiles for all pollutants. Furthermore, the posterior inclusion probability (PIP) results highlighted the consistent importance of cadmium and mercury with the inflammatory potential of an individual's diet, operationalized as the DII in our study, with both showing a PIP of 1.000. This was followed by PFOS with a PIP of 0.8524, PFOA at 0.5924, and lead, which had the lowest impact among the five environmental pollutants, with a PIP of 0.5596. Conclusion: Our study suggests that exposures to environmental metals and PFAS, particularly mercury and cadmium, are associated with DII. These findings also provide evidence of the intricate relationships between PFAS, heavy metals, and the DII. The findings underscore the importance of considering the cumulative effects of multi-pollutant exposures. Future research should focus on elucidating the mechanistic pathways and dose–response relationships underlying these associations in a study that examines causality, which will enable a deeper understanding of the dietary risks associated with environmental pollutants. [ABSTRACT FROM AUTHOR]

Genetic polymorphisms may influence mercury (Hg) toxicity. The aims of this study were to evaluate individual factors, such as the presence of the GSTP1 rs1695 polymorphism, associated with internal Hg dose and child neurodevelopment in indigenous people from the Brazilian Amazon chronically exposed to Hg. Eighty-two indigenous children were clinically evaluated, hair Hg was measured, and the GSTP1 rs1695 polymorphism was genotyped. The mean age was 4.8 years, the median Hg was 5.5 µg/g, and 93.8% of children exceeded the safe limit (2.0 µg/g). Fish consumption was associated with Hg levels (p = 0.03). The GSTP1 rs1695 A>G polymorphism was in the Hardy–Weinberg equilibrium and the highest prevalence of the GSTP1 AA genotype (80%) was found in Sawré Aboy, which had the highest Hg levels (10 µg/g) among the studied villages. The Hg levels tended to increase over the years in males and in carriers of the GSTP1 AA genotype (0.69 µg/g and 0.86 µg/g, respectively). Nine children failed the neurodevelopmental test, all of whom had Hg > 2.0 µg/g, and 88.9% carried the GSTP1 AA or AG genotypes, previously associated with the highest internal Hg doses and neurocognitive disorders. The genetic counseling of this population is important to identify the individuals at greater risk for neurodevelopmental disorders resulting from chronic Hg exposure. [ABSTRACT FROM AUTHOR]

The mercury cell manufacturing process, which has been extensively used in chlor-alkali plants to produce chlorine and caustic soda by electrolysis, represents a major source of Hg environmental pollution. At Saline di Volterra (Tuscany, Italy), solution mining by pumping water into halite deposits was applied to produce brines for a mercury-cell chlor-alkali plant. The Hg-contaminated, exhausted brines were pumped back at depth into the rock salt field in order to renew the available resources. Activities ceased in 1994, following the leakage dispersion of highly contaminated Hg(0)-bearing brines into the environment. The mercury content in the soil, measured during a survey conducted in 2000, reached 334 mg/kg, highlighting diffuse contamination in the floodplain. By 2009, the Hg concentration had generally decreased and was mostly confined to the topsoil layer. In order to evaluate the present Hg soil pollution, a geochemical survey was carried out in 2023, almost thirty years after the contamination event. The obtained data indicated the occurrence of legacy Hg, which reached 25.5 mg/kg in some soil samples. Speciation analysis for the most contaminated soil revealed that Hg(0) represented about 17.3% of the total Hg and that water-soluble and organic Hg fractions were negligible. These results suggest that the originally released metallic mercury has volatilized and likely oxidized, becoming practically immobile in the soil. A risk assessment, performed by applying Hg speciation analysis, indicated that the mercury in the soil does not carry a risk of non-cancerous effects for different exposure routes in case of subsequent use of the site and that the formerly contaminated area can now be converted into a leisure area. [ABSTRACT FROM AUTHOR]

Background: Since the 1960's, mercury (Hg) contamination of the aquatic environment of Asubpeeschoseewagong Anishinabek (Grassy Narrows First Nation) territories has impacted the community members' traditions, culture, livelihood, diet and health. Despite decreasing Hg exposure over time, a recent study suggested that long-term exposure contributed to later-life symptom clusters of nervous system dysfunction. Here, the objective was to evaluate, 5 years later, the prevalence and progression of these symptoms and examine the contribution of long-term, past Hg exposure. Methods: The symptom questionnaire, applied in the 2016/17 Grassy Narrows Community Health Assessment (GN-CHA) (Time 1), was re-administered in the 2021/22 Niibin study (Time 2). A total of 85 adults (median age: 47y; range: 29-75y) responded at both times. Paired statistics were used to test the differences (Time 2 – Time 1) in self-reported symptom frequencies. The symptom clustering algorithm, derived from the entire study group of the GN-CHA (n = 391), which had yielded 6 clusters, was applied at Time 1 and 2. Equivalent hair Hg measurements (HHg) between 1970 and 1997 were used in Longitudinal Mixed Effects Models (LMEM), with a sub-group with ≥ 10 repeated HHg mesurements (age > 40y), to examine its associations with symptom cluster scores and their progression. Results: For most symptoms, paired analyses (Time 2 – Time 1) showed a significant increase in persons reporting " very often" or "all the time", and in the mean Likert scores for younger and older participants (< and ≥ 50y). The increase in cluster scores was not associated with age or sex, except for sensory impairment where a greater increase in symptom frequency was observed for younger persons. LMEM showed that, for the sub-group, long-term past Hg exposure was associated with most cluster scores at both times, and importantly, for all clusters, with their rate of increase over time (Time 2 – Time 1). Conclusions: The persistence of reported symptoms and their increase in frequency over the short 5-year period underline the need for adequate health care services. Results of the sub-group of persons > 40y, whose HHg reflects exposure over the 28-year sampling period, suggest that there may be a progressive impact of Hg on nervous system dysfunction. [ABSTRACT FROM AUTHOR]

The air–sea exchange of elemental mercury (Hg0) plays an important role in the global Hg cycle. Existing air–sea exchange models for Hg0 have not considered the impact of sea surfactants and wave breaking on the exchange velocity, leading to insufficient constraints on the flux of Hg0. In this study, we have improved the air–sea exchange model of Hg0 in the three-dimensional ocean transport model MITgcm by incorporating sea surfactants and wave breaking processes through parameterization utilizing the total organic carbon concentration and significant wave height data. The inclusion of these factors results in an increase of over twofold in the transfer velocity of Hg0 relative to the baseline model. Air–sea exchange flux is increased in mid- to high-latitude regions with high wind and wave breaking efficiency, while it is reduced by surfactant and concentration change at low latitudes with low wind speeds and nearshore areas with low wave heights. Compared with previous parameterizations, the updated model demonstrates a stronger dependence of Hg0 air–sea exchange velocity on wind speed. Our results also provide a theoretical explanation for the large variances in estimated transfer velocity between different schemes. [ABSTRACT FROM AUTHOR]

Background: Obesity and metabolic syndrome are global health concerns associated with development of different types of diseases and serious health threats in the long term. Their metabolic imbalance can be attributable to inherited and environmental factors. As a considerable environmental agent, heavy metals exposure can predispose individuals to diseases like obesity. This systematic review and meta-analysis aimed to evaluate the association between heavy metals exposure and the risk of obesity. Methods: PubMed/MEDLINE, EMBASE and Web of Science were systematically searched until December 17, 2022. Only observational studies that evaluated heavy metals exposure and obesity were included. Studies were excluded if they assessed maternal or prenatal exposure, the mixture of heavy metals and other chemicals, reported the association with overweight or other diseases, and undesirable study designs. The Joanna Briggs Institute checklist was used for quality assessment. The pooled adjusted odds ratio (aOR) and the pooled standardized mean difference (SMD) with their 95% confidence intervals (CIs) were calculated, respectively. The publication bias was evaluated using Egger's and Begg's tests. Results: Twenty studies (n = 127755), four case–control and sixteen analytical cross-sectional studies, were included. Lead exposure was significantly associated with a lower risk of obesity (aOR: 0.705, 95% CI: 0.498–0.997), while mercury (aOR: 1.458, 95% CI: 1.048–2.031) and barium (aOR: 1.439, 95% CI: 1.142–1.813) exposure increased the risk of obesity. No significant publication bias was found and the studies had a low risk of bias. Conclusion: Overall, lead exposure reduced obesity risk, while mercury and barium exposure raised it. Further large-scale observational studies are recommended to determine the roles of heavy metals in obesity. Study registration ID: CRD42023394865. [ABSTRACT FROM AUTHOR]

In Xinjiang, China, a female corpse dating back to the Han Dynasty was discovered adorned in splendid attire crafted from wool fibers dyed in vibrant shades of red, blue, and light yellow. This study utilized fabric fragments as research specimens to analyze the dyes present, primarily employing time of flight secondary ion mass spectrometry (TOF-SIMS), in conjunction with optical microscopy, ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) and a mercury vapor analyzer for precise characterization. The TOF-SIMS analysis revealed the presence of mercury isotopic ions (202Hg+ and 199Hg+), mercury-sulfur ions (HgS+, m/z 234), sulfur isotopic ions (32S− and 34S−) on the surface of the red fiber samples. These findings suggest the utilization of cinnabar (HgS), a naturally occurring inorganic mineral dye, in the red fibers. Moreover, mercury content measurements indicated a significant enrichment of mercury in the red fibers, with the Hg content of 84 ng/g, markedly higher than the average Hg content of other fibers, which stood at 31 ng/g. Analysis of the blue fiber samples detected the quasi-molecular ion m/z 263 ([M+H]+) and a series of reasonable fragment ions, such as m/z 235 (C15H11N2O+) and m/z 247 (C16H11N2O+), indicative of the presence of indigo, a natural plant-based organic dye. UPLC-HRMS analysis further confirmed the presence of indigo in the blue fabric samples, providing cross-validation of the dye used. The light yellow fiber samples did not yield detections of common organic dyes like turmeric or inorganic pigments such as iron-yellow (Fe2O3H2O). The yellow hue observed in these fibers may be attributed to the natural aging of the original white wool, remaining undyed. Additionally, granular water-soluble inorganic ions such as NaCl, carbonate, and sulfate were detected within the yellow fabric samples. This study underscores the efficacy of the TOF-SIMS method for in-situ microanalysis and ultra-high sensitivity detection, rendering it is suitable for the analysis of both organic dye and inorganic dye. Moreover, TOF-SIMS will be widely used in archaeological and museum collections related research. [ABSTRACT FROM AUTHOR]

The recent COVID-19 pandemic has made everyone aware of the threat of viruses and the growing number of antibiotic-resistant bacteria. It has become necessary to find new methods to combat these hazards. One tool that could be used is UVC radiation, i.e., 100–280 nm. Currently, the available sources of this light are mercury vapor lamps. However, the modern world requires more compact, mercury-free, and less energy-consuming light sources. This work presents the results of our research on a new material in which efficient UVC radiation was obtained. Here, we present the results of research on Ca9Y(PO4)7 polycrystals doped with Pr3+ ions prepared using the solid-state method. The absorption, excitation, emission, and emission decay profiles of praseodymium(III) ions were measured and analyzed. The upconversion emission in the UVC region excited by blue light was observed. Parameters such as energy bandgap, refractive index, and thermal stability of luminescence were determined. The studied phosphate-based phosphor possesses promising characteristics that show its potential in luminescent applications in future use in medicine or for surface disinfection. [ABSTRACT FROM AUTHOR]

On the microscale, the Winchcombe CM carbonaceous chondrite contains a number of lithological units with a variety of degrees of aqueous alteration. However, an understanding of the average hydration state is useful when comparing to other meteorites and remote observations of airless bodies. We report correlated bulk analyses on multiple subsamples of the Winchcombe meteorite, determining an average phyllosilicate fraction petrologic type of 1.2 and an average water content of 11.9 wt%. We show the elemental composition and distribution of iron and iron oxidation state are consistent with measurements from other CM chondrites; however, Winchcombe shows a low Hg concentration of 58.1 ± 0.5 ng g−1. We demonstrate that infrared reflectance spectra of Winchcombe are consistent with its bulk modal mineralogy, and comparable to other CM chondrites with similar average petrologic types. Finally, we also evaluate whether spectral parameters can estimate H/Si ratios and water abundances, finding generally spectral parameters underestimate water abundance compared to measured values. [ABSTRACT FROM AUTHOR]

The dynamic change of redox conditions is a key factor in emission of elemental mercury (Hg0) from riparian soils. The objective of this study was to elucidate the influences of redox conditions on Hg0 emission from riparian soils. Soil suspension experiments were conducted to measure Hg0 emission from five Hg-contaminated soil samples in two redox conditions (i.e., treated with air or with N2). In four of the five samples, Hg0 emission was higher in air treatment than on N2 treatment. Remaining one soil, which has higher organic matter than other soils, showed no distinct difference in Hg0 production between air and N2 treatment. In soil suspensions subject to N2 treatment, the dissolved organic carbon (DOC) and Fe2+ concentrations were 3.38- to 1.34-fold and 1.44- to 2.28-fold higher than those in air treatment, respectively. Positive correlations were also found between the DOC and Fe2+ (r = 0.911, p < 0.01) and Hg2+ (r = 0.815, p < 0.01) concentrations in soil solutions, suggesting Fe2+ formation led to the release of DOC, which bound to Hg2+ in the soil and, in turn, limited the availability of Hg2+ for reduction to Hg0 in N2 treatment. On the other hand, for remaining one soil, more Hg2+ might be adsorbed onto the DOM in the air treatment, resulted in the inhibition of Hg0 production in air treatment. These results imply that the organic matter is important to prevent Hg0 production by changing redox condition. Further study is needed to prove the role of organic matter in the production of Hg0. [ABSTRACT FROM AUTHOR]

Siderophores are molecules that exhibit a high specificity for iron (Fe), and their synthesis is induced by a deficiency of bioavailable Fe. Complexes of Fe-siderophore are formed extracellularly and diffuse through porins across membranes into bacterial cells. Siderophores can bind heavy metals facilitating their influx into cells via the same mechanism. The aim of the studies was to determine the ability of siderophore-producing bacteria isolated from soils in the north-west part of Wedel Jarlsberg Land (Spitsbergen) to chelate non-Fe metals (Al, Cd, Co, Cu, Hg, Mn, Sn, and Zn). Specially modified blue agar plates were used, where Fe was substituted by Al, Cd, Co, Cu, Hg, Mn, Sn, or Zn in metal-chrome azurol S (CAS) complex, which retained the blue color. It has been proven that 31 out of 33 strains were capable of producing siderophores that bind to Fe, as well as other metals. Siderophores from Pantoea sp. 24 bound only Fe and Zn, and O. anthropi 55 did not produce any siderophores in pure culture. The average efficiency of Cd, Co, Cu, Mn, Sn, and Zn chelation was either comparable or higher than that of Fe, while Al and Hg showed significantly lower efficiency. Siderophores produced by S. maltophilia 54, P. luteola 27, P. luteola 46, and P. putida 49 exhibited the highest non-Fe metal chelation activity. It can be concluded that the siderophores of these bacteria may constitute an integral part of the metal bioleaching preparation, and this fact will be the subject of further research. [ABSTRACT FROM AUTHOR]

The exposure to arsenic and mercury in various insect trophic guilds from two mercury mining sites in Mexico was assessed. The two study sites were La Laja (LL) and La Soledad (LS) mines. Additionally, a reference site (LSR) was evaluated for LS. The terrestrial ecosystem was studied at LL, whereas both the terrestrial ecosystem and a stream called El Cedral (EC) were assessed at LS. The study sites are situated in the Biosphere Reserve Sierra Gorda (BRSG). Mercury vapor concentrations were measured with a portable analyzer, and concentrations of arsenic and mercury in environmental and biological samples were determined through atomic absorption spectrophotometry. Both pollutants were detected in all terrestrial ecosystem components (soil, air, leaves, flowers, and insects) from the two mines. The insect trophic guilds exposed included pollinivores, rhizophages, predators, coprophages, and necrophages. In LS, insects accumulated arsenic at levels 29 to 80 times higher than those found in specimens from LSR, and 10 to 46 times higher than those from LL. Similarly, mercury exposure in LS was 13 to 62 times higher than LSR, and 15 to 54 times higher than in LL. The analysis of insect exposure routes indicated potential exposure through air, soil, leaves, flowers, animal prey, carrion, and excrement. Water and sediment from EC exhibited high levels of arsenic and mercury compared to reference values, and predatory aquatic insects were exposed to both pollutants. In conclusion, insects from mercury mining sites in the BRSG are at risk. [ABSTRACT FROM AUTHOR]

Purpose: Pejão Mining Complex locates in Castelo de Paiva municipality and, until its closure in 1994, was one of the most important coal mines in the Douro Coalfield. This work aims to study the presence, quantify, and evaluate the dissemination of mercury (Hg), a potentially toxic element (PTE) of major public health concern by the World Health Organization (WHO), from a waste pile affected by coal fires. Materials and methods: Samples from areas affected and unaffected by the combustion and from surrounding soil were collected from Fojo waste pile region. First, the Hg pseudo-total concentration was estimated for all collected samples by soil microwave–assisted digestion with aqua regia (USEPA 3051A). Then, a sequential extraction procedure (SEP), the USEPA 3200, was applied for Hg fractionation and speciation aiming to evaluate Hg mobility and bioavailability to surrounding ecosystems. Results and discussion: The results obtained showed a Hg enrichment in soil samples when compared to Portuguese and international reference values for soils. Relatively to the Hg availability and mobility, although it predominates in the semi-mobile fraction, the waste pile materials exposed to combustion showed a concerning increase of Hg levels in the mobile fraction that contains the more labile Hg species, being a major source of environmental contamination by Hg. Conclusions: This study allowed to conclude that combustion of mining residues increased Hg mobility, toxicity, and bioavailability, increasing the contamination potential of the coal waste pile. The methodology applied in this work can be replicated in other abandoned mines to monitor, control, and/or mitigate the Hg environmental impact in the surrounding soils and waters. [ABSTRACT FROM AUTHOR]

The consumption of fish in food may contain mercury, a harmful element and dangerous chemical detrimental to human health. The purpose of this study was to determine the mercury level in the hair of pregnant women with different fish intakes in their diets. The concentration of total mercury in hair was determined using an atomic absorption spectrometer. In this study, 98 pregnant women were invited to participate (aged from 18 to 48 years). The mean content of mercury in the hair of pregnant women in Northwestern Russia was 0.428 mg/kg (ranging from 0.018 to 3.1 mg/kg). As a result, 22% of women had mercury values above 0.58 mg/kg, which is considered dangerous for the fetus. The hair mercury concentration in a village area was higher than that in a city area (i.e., 0.548 mg/kg and 0.326 mg/kg). Moreover, the maximum level of mercury was noted for a group of pregnant women who consumed more than 5 kg/month of fish and fish products. Furthermore, the consumption of freshwater fish in the diet leads to a higher mercury content in the hair of pregnant women than the consumption of marine fish. [ABSTRACT FROM AUTHOR]

The substantial amount of mercury emissions from coal-fired flue gas causes severe environmental contamination. With the Minamata Convention now officially in force, it is critical to strengthen mercury pollution control. Existing activated carbon injection technologies suffer from poor desulfurization performance and risk secondary-release risks. Therefore, considering the potential industrial application of adsorbents, we selected cost-effective and readily available activated coke (AC) as the carrier in this study. Four metal selenides—copper, iron, manganese, and tin—were loaded onto the AC to overcome the application problems of existing technologies. After 120 min of adsorption, the CuSe/AC exhibited the highest efficiency in removing Hg0, surpassing 80% according to the experimental findings. In addition, the optimal adsorption temperature window was 30–120 °C, the maximum adsorption rate was 2.9 × 10−2 mg·g−1·h−1, and the effectiveness of CuSe/AC in capturing Hg0 only dropped by 5.2% in the sulfur-containing atmosphere. The physicochemical characterization results indicated that the AC surface had a uniform loading of CuSe with a nanosheet structure resembling polygon and that the Cu-to-Se atomic ratio was close to 1:1. Finally, two possible Hg0 reaction pathways on CuSe/AC were proposed. Moreover, it was elucidated that the highly selective binding of Hg0 with ligand-unsaturated Se− was the key factor in achieving high adsorption efficiency and sulfur resistance in the selenium-functionalized AC adsorbent. This finding offers substantial theoretical support for the industrial application of this adsorbent. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a global atmospheric pollutant. In its oxidized form (HgII), atmospheric Hg can readily deposit to ecosystems, where it may bioaccumulate and cause severe health effects. High HgII concentrations are reported in the free troposphere, but spatiotemporal data coverage is limited. Underestimation of HgII by commercially available measurement systems hinders quantification of Hg cycling and fate. During spring-summer 2021 and 2022, we measured elemental (Hg0) and oxidized Hg using a calibrated dual-channel system alongside trace gases, aerosol properties, and meteorology at the high-elevation Storm Peak Laboratory (SPL) above Steamboat Springs, Colorado. Oxidized Hg concentrations displayed temporal behavior similar to previous work at SPL, but were approximately three times higher in magnitude due to improved measurement accuracy. We identified 18 multi-day events of elevated HgII (mean enhancement: 36 pg m-3) that occurred in dry air (mean ± s.d. RH = 32 ± 16 %). Lagrangian particle dispersion model (HYSPLIT-STILT) 10-day back-trajectories showed that the majority of transport prior to events occurred in the low to mid-free troposphere. Oxidized Hg was anticorrelated with Hg0 during events, with an average (± s.d.) slope of -0.39 ± 0.14, suggestive of upwind oxidation followed by deposition during transport. Concurrent sulfur dioxide measurements verified that three upwind coal-fired power plants did not measurably contribute ambient Hg at SPL. Principal Components Analysis revealed HgII consistently inversely related with Hg0 and was generally not associated with combustion tracers, confirming oxidation in the clean, dry free troposphere as its primary origin. [ABSTRACT FROM AUTHOR]

Dental amalgams have been used by dentists for the restoration of posterior human teeth. However, there have been concerns about the release of mercury from amalgams into the oral cavity. The objective of the present research is to study the effect of titanium (Ti) nanoparticles on the microstructural mechanism of the release of mercury vapor in two commonly used brands of dental amalgam (the Dispersalloy: 11.8% Cu; the Sybralloy: 33% Cu). Ti powder was added to both the Dispersalloy and the Sybralloy in increments of 10 mg up to 80 mg. The addition of Ti powder to both brands of dental amalgam has been found to result in a considerable decrease in Hg vapor release. The decrease in the Hg vapor release due to Ti addition has been explained by the formation of strong Hg–Ti covalent bonds, which reduce the availability of Hg atoms for evaporation. The Ti atoms in excess of the solubility limit of Ti in Hg reside in the grain boundaries, which also reduces the evaporation of Hg from the amalgam. The binding of Hg with Ti via a strong covalent bond also results in a significant improvement in mechanical properties such as Vickers hardness. [ABSTRACT FROM AUTHOR]

The allele and genotype frequencies of the polymorphic loci CYP1A1 (rs1048943), GSTP1 (rs1695 and rs1138272), GSTM1, and GSTT1 genes were studied in 517 men: in 389 accumulated mercury pollution liquidators (207 firefighters of the Ministry of the Russian Federation for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters and 182 employees of the Federal Environmental Operator) and 128 former workers (82 patients in the delayed period of chronic mercury intoxication and 46 individuals contacted with mercury and had no chronic mercury intoxication). We found differences in the frequencies of AA and AG genotypes in groups of former workers (χ2=6.96, p=0.008) for the polymorphic locus rs1048943, while the AG-CYP1A1 genotype was characterized by a 5.5-fold decrease in the odds ratio for the development of chronic mercury intoxication (OR=0.18, p=0.0041). An unfavorable combination of genotypes of the studied polymorphic loci increases the risk of undesirable health effects. [ABSTRACT FROM AUTHOR]

The article provides clinical tips and tricks for rubber dam isolation in dental procedures, emphasizing techniques to ensure proper placement, prevent accidental tears, and improve patient comfort. It also discusses various scenarios for isolation, including single-tooth and multiple-teeth isolation, detailing indications, advantages, and disadvantages for each method.

Mercury is a ubiquitous environmental xenobiotic; the primary sources of exposure to this metal are artisanal gold mining and the direct production of mercury. In Mexico, artisanal mercury mining continues to be an important activity in different regions of the country. Exposure to mercury vapors releases can have severe health impacts, including immunotoxic effects such as alterations in cytokine profiling. Therefore, in the present work, we evaluated the inflammatory cytokines profile in the blood serum of miners exposed to mercury. A cross-sectional observational study was performed on 27 mining workers (exposed group) and 20 control subjects (nonexposed group) from central Mexico. The mercury urine concentration (U-Hg) was determined by atomic absorption spectrometry, and IL-2, IL-6, IL-8, IL-10, and TNF-α were measured using a Multiplex Assay. The results showed that the U-Hg in the miners had a median value of 552.70 μg/g creatinine. All cytokines showed a significant increase in the miner group compared with the control group, except for TNF-α. In addition, we observed a positive correlation between U-Hg concentration and cytokine levels. In conclusion, mercury exposure correlated with cytokine levels (considered acute inflammatory marker) in miners; therefore, workers exposed to this metal show an acute systemic inflammation that could lead to alterations in other organs and systems. [ABSTRACT FROM AUTHOR]

A gaseous elemental mercury (Hg0) sampler was developed for the assessment of mercury (Hg) pollution from the air and utilised aluminium (Al) powder as the accumulation medium. The Hg sampler is presented as an alternative cost-effective sorbent that can be used for the assessment of Hg pollution in atmospheric air in areas where natural bio-indicators such as lichens and moss do not grow, including the urban environments. The chemical treatment of Al materials was necessary to weaken the aluminium oxide (Al2O3) layer to increase the adsorption capability of Al material. Treated Al samples were exposed to Hg vapours for one hour to two weeks in a Hg atmosphere chamber. Other Al powder samples were exposed to the ambient air at areas of the Tshwane Metropolitan Municipality for six to ten months. The analysis of samples by an RA-915+ Zeeman mercury analyser showed that the limit of detection (LOD) and limit of quantification (LOQ) for the determination of Hg in Al powder with a mass of 100 mg were found to be 0.31 ng g−1 and 1.0 ng g−1, respectively. The content of Hg that accumulated on Al powder was linear from 0.1 to 25 ng g−1, thus enabling the measurement of Hg accumulation from air at the global average concentration level. Mercury from air that accumulated on Al powder in the Tshwane Metropolitan Municipality ranged between 70 ng g−1 and 155 ng g−1. [ABSTRACT FROM AUTHOR]

Rationale: Use of electronic drug delivery systems (EDDS, "e-cigarettes") to ingest nicotine and Δ9-tetrahydrocannabinol (THC) has surged in adolescents in the USA; five times as many high-school seniors vape nicotine daily using tobacco. At the same time, 19.5% of seniors use cannabis at least monthly, with 12% using EDDS to deliver it. Objectives: This study was conducted to examine the impact of repeated adolescent vapor inhalation of nicotine and THC in rats. Methods: Female Sprague–Dawley rats were exposed to 30-min sessions of vapor inhalation, twice daily, from post-natal day (PND) 31 to PND 40. Conditions included vapor from the propylene glycol (PG) vehicle, nicotine (60 mg/mL in the PG), THC (100 mg/mL in the PG), or the combination of nicotine (60 mg/mL) and THC (100 mg/mL). Rats were assessed on wheel activity, heroin anti-nociception and nicotine and heroin vapor volitional exposure during adulthood. Results: Nicotine-exposed rats exhibited few differences as adults, but were less sensitive to anti-nociceptive effects of heroin (1 mg/kg, s.c.). THC- and THC + nicotine–exposed rats were less spontaneously active, and obtained fewer nicotine vapor deliveries as adults. In contrast, THC-exposed rats obtained volitional heroin vapor at rates indistinguishable from the non-THC-exposed groups. Repeated THC exposure also caused tolerance to temperature-disrupting effects of THC (5 mg/kg, i.p.). Conclusions: These studies further confirm that the effects of repeated vapor exposure to THC in adolescence last into early to middle adulthood, including decreased volitional consumption of nicotine. Effects of repeated nicotine in adolescence were comparatively minor. [ABSTRACT FROM AUTHOR]

Geobarometers are commonly used to determine the pressure (and hence depth) of magmatic bodies. For instance, at equilibrium, the concentration of dissolved volatiles in a vapor-saturated melt can be used as a barometer: this is the pressure of vapor-saturation P s a t v . Most determinations of P s a t v assume that melt and vapor contain only oxidized C-O-H species. However, sulfur is the third most abundant volatile element in magmas, and oxygen fugacity f O 2 exerts a strong influence on the speciation of the melt and vapor. To explore how S and f O 2 afect calculations of P s a t v , we model a Hawaiian tholeiite that contains both reduced and oxidized C-O-H-S species in the melt and vapor. We find that excluding reduced CO-H species in the system can result in significant underestimations of P s a t v under reducing conditions (ΔFMQ < 0). The efect of S on P s a t v is small except in the vicinity of the "sulfur solubility minimum" (SSmin; 0 < ΔFMQ < +2), where excluding S-bearing species can result in underestimates of P s a t v . The implications of these results depend on the volatile concentration of the system being investigated, its fO2, and the melt composition and temperature. Our results suggest there will be little impact on P s a t v calculated for mid-ocean ridge basalts because their f O 2 is above where reduced C-O-H species become important in the melt and vapor and yet below the SSmin. However, the f O 2 of ocean island and arc basalts are close enough to the SSmin and their S concentrations high enough to influence P s a t v . However, high-CO2 and high-H2O concentrations are predicted to reduce the efect of the SSmin. Hence, P s a t v calculated for shallowly trapped melt inclusions and matrix glass are more afected by the SSmin than deeply trapped melt inclusions. Lunar and martian magmas are typically more reduced than terrestrial magmas, and therefore accurate P s a t v calculations for them require the inclusion of reduced C-O-H species. [ABSTRACT FROM AUTHOR]

We synthesized a boron-doped reduced graphene oxide (BrGO) material characterized by various electrical properties, through simultaneous thermal reduction and doping procedures, using a metal–organic chemical vapor deposition technique. X-ray photoelectron spectroscopy (XPS) was used to study the impact of the doping level on the B bonding in the reduced graphene oxide (rGO) layer that is influenced by the annealing temperature. The synthesized BrGO layer demonstrated a high B concentration with a considerable number of O-B bonds, that were altered by annealing temperatures. This resulted in a decreased work function and the formation of a Schottky contact between the BrGO and n-type Si substrate. Due to the higher proportion of B-C and B-C3 bonding in the BrGO/Si device than that in the rGO/Si, the decreased Schottky barrier height of the BrGO/n-Si vertical junction photodetector resulted in a higher responsivity. This study showcases a promise of a simple B-doping method in use to alter the electrical characteristics of graphene materials. [ABSTRACT FROM AUTHOR]

Evidence is presented that the metaconglomerate-hosted Jacobina gold deposits in Brazil represent paleoplacers that became partly remobilized during later metamorphic overprint analogous to Witwatersrand-type deposits elsewhere, notably in South Africa. This includes strong lithological and sedimentological control on the gold, presence of detrital minerals with gold inclusions, and detrital gold particles. Detrital, synsedimentary, and post-depositional pyrite types can be differentiated. Whereas the first two types can be linked to gold accumulation, the latter was associated with gold dispersion. Synsedimentary pyrite has the highest Au content, from which elevated Au concentrations in Archean rivers can be inferred. The nature and extent of post-depositional alteration, mainly in the course of the Paleoproterozoic Orogeny, distinguishes the Jacobina deposits from other Witwatersrand-type gold deposits. Phase equilibria and Zr-in-rutile thermometry indicate peak metamorphic temperatures of ca. 600 °C. Both Mg-chlorite and Fe-chlorite formed in disequilibrium at approximately 280–340 °C during retrograde metamorphism. An igneous signature in the chemistry of some of the tourmaline and the remobilization of gold associated with Fe-oxides, near intrusive rocks, point at a local magmatic influence on the post-depositional mineralization stage. Whether magmatic hydrothermal fluids added Au to the system at that stage remains to be determined. Remobilization during regional metamorphism was insufficient to form substantial ore bodies but led to purification of the initially detrital gold particles that now contain relatively little Ag and Cu and lack Hg. [ABSTRACT FROM AUTHOR]

The elemental mercury (Hg0) release characteristics from the Hg-contaminated soil applied with Humic acid fertilizer (HAF) in the greenhouse were identified. The adsorption features of mercuric ion (Hg2+) on HAF under different reaction times and pH were investigated to elucidate the influencing mechanism of HAF on soil Hg0 release. Besides, the microstructure of HAF loading with Hg2+ was characterized by using Fourier transform infrared spectroscopy (FTIR) and scanning electron micrograph-energy dispersive spectrometry-EDS). The results showed that with the increasing HAF dosage, soil oxidation-reduction potential (Eh), and organic matter (SOM) content, as well as the decreasing soil pH, the soil Hg0 release fluxes showed a decreasing tendency. The soil pH, Eh, SOM, and total Hg content are the key factors that can affect the soil Hg0 release fluxes. The interior air temperature, light intensity, soil moisture, and soil temperature have little impact on soil Hg0 release fluxes when the greenhouse soil is applied with HAF. The HAF can immobilize Hg2+ and reduce its activity by surface precipitation and specific adsorption, then affecting the soil Hg0 release fluxes. The results of this study provide a basis for the application of HAF to reduce soil Hg0 release fluxes in the greenhouse of Hg-contaminated areas. [ABSTRACT FROM AUTHOR]

Mercury (Hg) pollution is a global public health concern because of its adverse effects on the environment and health. Single-nucleotide polymorphisms (SNPs) have been associated with Hg levels and outcomes. The aim of this review was to describe the research and discuss the evidence on the genetic susceptibility of Hg-exposed individuals to the development of neurocognitive disorders. A systematic review was performed to identify the genes/SNPs associated with Hg toxicokinetics and that, therefore, affect neurological function in exposed populations. Observational and experimental studies were identified by screening three databases. Thirteen articles were included (quality score 82–100%) and 8124 individuals were evaluated. Hg exposure was mainly fish consumption (77%) and, in 31% of the studies, the Hg levels exceeded the reference limits. Genetic susceptibility to higher Hg levels and neurotoxicity risk in Hg poisoning were associated with eight (ALAD rs1800435, CYP3A4 rs2740574, CYP3A5 rs776746, CYP3A7 rs2257401, GSTP1 rs1695, MT1A rs8052394, MT1M rs2270836, and MT4 rs11643815) and three (MT1A rs8052394, MT1M rs2270837, and MT2A rs10636) SNPs, respectively, and rs8052394 was associated with both outcomes. The MT1A rs8052394 SNP may be used as a susceptibility biomarker to identify individuals at greater risk for higher Hg levels and the development of neurocognitive disorders in metal-exposed populations. [ABSTRACT FROM AUTHOR]

The monitoring of low gaseous elemental mercury (GEM) concentrations in the atmosphere requires continuous high-resolution measurements and corresponding calibration capabilities. Currently, continuous calibration for GEM is still an issue at ambient concentrations (1–2 ngm-3). This paper presents a continuous flow calibration for GEM, traceable to NIST 3133 Standard Reference Material (SRM). This calibration approach was tested using a direct mercury analyser based on atomic absorption spectrometry with Zeeman background correction (Zeeman AAS). The produced continuous flow of GEM standard was obtained via the reduction of Hg2+ from liquid NIST 3133 SRM and used for the traceable calibration of the Zeeman AAS device. Measurements of atmospheric GEM using the calibrated Zeeman AAS were compared with two methods: (1) manual gold amalgamation atomic fluorescence spectrometry (AFS) calibrated with the chemical reduction of NIST 3133 and (2) automated gold amalgamation AFS calibrated using the mercury bell-jar syringe technique. The comparisons showed that a factory-calibrated Zeeman AAS device underestimates concentrations under 10 ngm-3 by up to 35 % relative to the two other methods of determination. However, when a calibration based on NIST 3133 SRM was used to perform a traceable calibration of the Zeeman AAS, the results were more comparable with other methods. The expanded relative combined uncertainty for the Zeeman AAS ranged from 8 % for measurements at the 40 ngm-3 level to 91.6 % for concentrations under 5 ngm-3 using the newly developed calibration system. High uncertainty for measurements performed under 5 ngm-3 was mainly due to instrument noise and concentration variation in the samples. [ABSTRACT FROM AUTHOR]

Autoimmune diseases are multifactorial and include environmental as well as genetic drivers. Although much progress has been made in understanding the nature of genetic underpinnings of autoimmune disease, by comparison much less is understood regarding how environmental factors interact with genetics in the development of autoimmunity and autoimmune disease. In this report, we utilize the (New Zealand black × New Zealand white [NZB × NZW]) F1 mouse model of systemic lupus erythematosus (SLE). Mercury is a xenobiotic that is environmentally ubiquitous and is epidemiologically linked with the development of autoimmunity. Among other attributes of human SLE, (NZB × NZW) F1 mice spontaneously develop autoimmune-mediated kidney disease. It has been previously shown that if (NZB × NZW) F1 mice are exposed to inorganic mercury (Hg2+), the development of autoimmunity, including autoimmune kidney pathology, is accelerated. We now show that in these mice, the development of kidney disease is correlated with a decreased percentage of marginal zone (MZ) B-cells in the spleen. In Hg2+-intoxicated mice, kidney disease is significantly augmented, and matched by a greater decrease in MZ B-cell splenic percentages than found in control mice. In Hg2+- intoxicated mice, the decrease in MZ B-cells appears to be linked to aberrant B-cell receptor signal strength in transitory 2 (T2) B-cells, developmental precursors of MZ B-cells. [ABSTRACT FROM AUTHOR]

In this work, a comparison was made between the synthesis of niobium-based materials (Nb2O5), both in terms of material characterization and catalytic performance. The methods used were chemical mixtures: modified sol-gel and Pechini. The materials were calcined at different temperatures (753, 873 and 993K) and characterized by the following techniques: photoacousticspectroscopy (PAS), zero charge point (pHPZC), scanning electron microscopy (SEM/EDS), thermogravimetric analysis (TGA/DTG) and X-ray diffraction (XRD). The photocatalytic process was carried out to evaluate the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV radiation (250 W mercury vapor lamp) and different experimental conditions. In addition, to better understand the influence of parameters such as pH, catalyst concentration (0.2, 0.5 and 0.8 g L−1) and calcination temperature, a Design of Experiments (DoE) was used. The results indicated that despite having similar structures and phases in the XRD analysis, the morphology presents two distinct surfaces, due to the preparation method. Differences in the synthesis method affected the catalytic activity in the parameters studied. Although the zero charge point values are close (6.18-6.36), we observed differences in the band gap depending on the calcination temperature. In the optimal condition studied, the catalyst prepared by the sol-gel method obtained the best results. [ABSTRACT FROM AUTHOR]