Search

When using quantum chemical methods to study electronically excited states of open-shell molecules, it is often beneficial to start with wave functions that are spin eigenfunctions. For excited states of molecules containing heavy elements, spin–orbit coupling (SOC) is important and needs to be included as well. An efficient approach is to include SOC perturbatively on top of a restricted open-shell Kohn–Sham (ROKS) time-dependent density functional theory, which can be combined with the Tamm–Dancoff approximation (TDA) to suppress numerical instabilities. We implemented and assessed the potential of such a ROKS-TDA-SOC method, also featuring the possibility of calculating transition dipole moments between states to allow for full spectrum simulation. Our study shows that the ROKS-TDA-SOC formalism yields a clear and easy-to-use method to obtain electronically excited states of open-shell molecules that are of moderate size and contain heavy elements. [ABSTRACT FROM AUTHOR]

The rapid development of deep learning techniques has driven the emergence of a neural network-based variational Monte Carlo (VMC) method (referred to as FermiNet), which has manifested high accuracy and strong predictive power in the electronic structure calculations of atoms, molecules, and some periodic systems. Recently, the implementation of the effective core potential (ECP) scheme has further facilitated more efficient calculations in practice. However, there is still a lack of comprehensive assessments of the ECP's performance under the FermiNet. In this work, we set sail to fill this gap by conducting extensive tests on the first two row elements regarding their atomic, spectral, and molecular properties. Our major finding is that, in general, the qualities of ECPs have been correctly reflected under FermiNet. Two recently built ECP tables, namely, correlation consistent ECP (ccECP) and energy consistent correlated electron pseudopotential (eCEPP), seem to prevail in terms of overall performance. In particular, ccECP performs slightly better on spectral precision and covers more elements, while eCEPP is more systematically built from both shape and energy consistency and better treats the core polarization. On the other hand, the high accuracy of the all-electron calculations is hindered by the absence of relativistic effects as well as the numerical instabilities in some heavier elements. Finally, with further in-depth discussions, we generate possible directions for developing and improving FermiNet in the near future. [ABSTRACT FROM AUTHOR]

We report on the quantitative nondestructive analysis of the natural isotopic abundances of hafnium and tungsten elements using nuclear resonance fluorescence. Metallic samples of hafnium and tungsten were irradiated to six quasi-monochromatic γ -ray beams generated by laser Compton scattering in the energy range of 2.4–3.2 MeV. Multiple nuclei were simultaneously excited at each of the six γ -ray beam energies. A high-purity germanium detector array detected deexcitations of the nuclei. In total, 51 transitions were unprecedentedly employed to estimate the isotopic abundances of heavy elements nondestructively. The estimated abundances of three hafnium isotopes and three tungsten isotopes are consistent with standard known natural abundances within the experimental uncertainties. The deviation from the standard values ranges from 0.18 % to 1.36 %. [ABSTRACT FROM AUTHOR]

We construct correlation-consistent effective core potentials (ccECPs) for a selected set of heavy atoms and f elements that are currently of significant interest in materials and chemical applications, including Y, Zr, Nb, Rh, Ta, Re, Pt, Gd, and Tb. As is customary, ccECPs consist of spin–orbit (SO) averaged relativistic effective potential (AREP) and effective SO terms. For the AREP part, our constructions are carried out within a relativistic coupled-cluster framework while also taking into account objective function one-particle characteristics for improved convergence in optimizations. The transferability is adjusted using binding curves of hydride and oxide molecules. We address the difficulties encountered with f elements, such as the presence of large cores and multiple near-degeneracies of excited levels. For these elements, we construct ccECPs with core–valence partitioning that includes 4f subshell in the valence space. The developed ccECPs achieve an excellent balance between accuracy, size of the valence space, and transferability and are also suitable to be used in plane wave codes with reasonable energy cutoffs. [ABSTRACT FROM AUTHOR]

Localized atomic orbitals are the preferred basis set choice for large-scale explicit correlated calculations, and high-quality hierarchical correlation-consistent basis sets are a prerequisite for correlated methods to deliver numerically reliable results. At present, numeric atom-centered orbital (NAO) basis sets with valence correlation consistency (VCC), designated as NAO-VCC-nZ, are only available for light elements from hydrogen (H) to argon (Ar) [Zhang et al., New J. Phys. 15, 123033 (2013)]. In this work, we extend this series by developing NAO-VCC-nZ basis sets for krypton (Kr), a prototypical element in the fourth row of the periodic table. We demonstrate that NAO-VCC-nZ basis sets facilitate the convergence of electronic total-energy calculations using the Random Phase Approximation (RPA), which can be used together with a two-point extrapolation scheme to approach the complete basis set limit. Notably, the Basis Set Superposition Error (BSSE) associated with the newly generated NAO basis sets is minimal, making them suitable for applications where BSSE correction is either cumbersome or impractical to do. After confirming the reliability of NAO basis sets for Kr, we proceed to calculate the Helmholtz free energy for Kr crystal at the theoretical level of RPA plus renormalized single excitation correction. From this, we derive the pressure–volume (P–V) diagram, which shows excellent agreement with the latest experimental data. Our work demonstrates the capability of correlation-consistent NAO basis sets for heavy elements, paving the way toward numerically reliable correlated calculations for bulk materials. [ABSTRACT FROM AUTHOR]

Pseudopotentials (PP) are extensively used in electronic structure calculations, particularly for molecules containing heavy elements. Parameters in PPs are mainly determined from ab initio results, and errors of such PPs in density functional theory (DFT) calculations have been studied previously. However, PP errors on results with spin–orbit coupling and those in time-dependent DFT (TDDFT) calculations have not been reported previously. In this work, we investigate the error of the small-core energy-consistent Stuttgart/Koln pseudopotentials in DFT and TDDFT calculations with and without spin–orbit coupling. Ground state bond lengths, harmonic frequencies, dissociation energies, and vertical excitation energies for a series of closed-shell diatomic heavy and superheavy p-block molecules are calculated using several popular exchange-correlation functionals. PP errors are estimated by comparing with results using the all-electron Dirac–Coulomb (-Gaunt) Hamiltonian. Our results show that the difference between ground state properties and most excitation energies in scalar-relativistic calculations with the PP and those of all-electron calculations is quite small. This difference becomes somewhat larger when spin–orbit coupling (SOC) is present, especially for properties that are affected by SOC to some extent. In addition, the errors of the PPs are insensitive to the employed exchange-correlation functionals in most cases. Our results indicate that reasonable DFT and TDDFT results can be obtained using the small-core energy-consistent Stuttgart/Koln pseudopotentials for heavy and super-heavy p-block molecules. [ABSTRACT FROM AUTHOR]

Asthma start, development, and exacerbation have all been linked in numerous studies to exposure to a variety of metal elements. However, there is still a dearth of epidemiological data linking heavy metal exposure to death in asthmatics. The investigation included 2432 eligible adults with asthma. The study examined the possible correlation between blood heavy metal levels and all-cause mortality. This was done by utilizing Cox proportional hazards models, restricted cubic spline (RCS), threshold effect models, and CoxBoost models. Subgroup analyses were conducted to investigate the associations between blood metal levels and all-cause mortality among distinct asthmatic populations. An inverse association was found between blood selenium and all-cause mortality in asthmatics, while blood manganese showed a positive association with all-cause mortality. However, there were no significant connections found between blood lead, cadmium, mercury, and all-cause mortality via multivariate Cox proportional hazard models. In model 3, after accounting for all factors, all-cause mortality dropped by 10% for every additional 10 units of blood selenium (μg/L) and increased by 6% for every additional unit of blood manganese (μg/L). The RCS and threshold effect model found a U-shaped correlation between blood selenium, blood manganese, and all-cause mortality. The lowest all-cause mortality among asthmatics was observed when blood selenium and manganese were 188.66 μg/L and 8.47 μg/L, respectively. Our investigation found a U-shaped correlation between blood selenium levels, blood manganese levels, and all-cause mortality in asthmatic populations. Optimizing dietary selenium intake and effectively managing manganese exposure could potentially improve the prognosis of asthma. [ABSTRACT FROM AUTHOR]

The Edelstein effect is the origin of the spin-orbit torque: a current-induced torque that is used for the electrical control of ferromagnetic and antiferromagnetic materials. This effect originates from the relativistic spin-orbit coupling, which necessitates utilizing materials with heavy elements. Here, we show that in magnetic materials with non-collinear magnetic order, the Edelstein effect and, consequently, a current-induced torque can exist even in the absence of the spin-orbit coupling. Using group symmetry analysis, model calculations, and realistic simulations on selected compounds, we identify large classes of non-collinear magnet candidates and demonstrate that the current-driven torque is of similar magnitude as the celebrated spin-orbit torque in conventional transition metal structures. We also show that this torque can exist in an insulating material, which could allow for highly efficient electrical control of magnetic order. A major goal of spintronics is to manipulate magnetic order with electric fields. The typical approach is to use a material with spin-orbit coupling, and the resulting Edelstein effect. Here, González-Hernández et al. show theoretically that non-collinear magnets can also host an Edelstein effect, even in the absence of spin-orbit coupling. [ABSTRACT FROM AUTHOR]

Heavy metal contamination in soils and vegetation poses a significant problem due to its toxicity and persistence. Toxic effects on vegetation include not only impaired growth, reduced yields, and even plant death but also biodiversity loss and ecosystem degradation. Addressing this issue requires comprehensive monitoring and remediation efforts to mitigate the environmental, human health, and ecological impacts. This review examines the state-of-the-art methodologies and advancements in remote sensing applications for detecting and monitoring heavy metal contamination in soil and its subsequent effects on vegetation. By synthesizing the current research findings and technological developments, this review offers insights into the efficacy and potential of remote sensing for monitoring heavy metal contamination in terrestrial ecosystems. However, current studies focus on regression and AI methods to link spectral reflectances and indices to heavy metal concentrations, which poses limited transferability to other areas, times, spectral discretizations, and heavy metal elements. We conclude that one important way forward is the more thorough understanding and simulation of the related physico-chemical processes in soils and plants and their effects on the spectral signatures. This would offer a profound basis for remote sensing applications for individual circumstances and would allow disentangling heavy metal effects from other stressors such as droughts or soil salinity. [ABSTRACT FROM AUTHOR]

In this paper, the Chinese Taoist medicinal herb Codonopsis and its rhizosphere soils from Pingshun County, Shanxi Province, were used as the research objects. Using GIS, descriptive statistics, The BP neural network model constructed by Python, we studied the potential factors to control the enrichment and migration of heavy metal elements in the soil-Codonopsis system under different sources. It was found that the heavy metal elements in the soils of the region were mainly divided into natural background and source of mineral veins, and the content of heavy metal elements in Codonopsis and rhizosphere soils under vein sources was found to be higher than the natural background, while there was no significant change in the corresponding rhizosphere soils, and the biological effectiveness of heavy metal elements in Codonopsis under vein sources was significantly increased, among which Cu, Cd were even more enriched. The bioeffectiveness of heavy metal elements in Codonopsis from mineral veins was significantly increased, among which cu and cd were superenriched. The migration of most heavy metal elements in the natural background was mainly influenced by soil pH, while in the case of mineral vein contamination, the key factors controlling the migration of heavy metal elements were mainly inter-element interactions. Therefore, the subsequent planting of Codonopsis should be far away from the area of vein development and focus on the effect of pH on its quality. [ABSTRACT FROM AUTHOR]

This study quantified the concentrations of trace and heavy elements, including Al, K, Ca, Mg, Zr, Ti, La, Ce, Mn, Cr, Zn, and Nd, in soil samples from Tukwikwi. It also assesses the potential human health risks posed by exposure to these metals through ingestion, inhalation, and dermal absorption for both children and adults. The study area lies in Hadejia flood plain between latitudes 12°10′ N to 13°0′ N and longitudes 10°15′ E to 11°30′ E. The result showed that the mean concentrations of Al (47,140 mg/kg), K (23,110 mg/kg), Fe (18,020 mg/kg), Mg (7810 mg/kg), Zr (404 mg/kg), and La (64 mg/kg) exceeded the crustal values of Al (25,000 mg/kg), K (10,700 mg/kg), Fe (9800 mg/kg), Mg (7000 mg/kg), Zr (220 mg/kg), and La (30 mg/kg). By contrast, the concentrations of Ca, Cr, Ce, Mn, Ti, Zn, and Nd were lower than the crustal values. These crustal values were used, as there were no regional values that could be used for comparison. The result of the noncarcinogenic health risk assessment showed that Al exhibited the highest value ranging from 5.52×10−1$5.52 \times {{10}^{ - 1}}$ to 7.51×10−1$7.51 \times {{10}^{ - 1}}$ for children and 7.3×10−1$7.3 \times {{10}^{ - 1}}$ to 9.9×10−1$9.9 \times {{10}^{ - 1}}$ for adults. The results also revealed that adults have a higher potential risk than children. The results for the carcinogenic risk (CR) showed that the total CR (TCR) values for Cr ranged from 0 to 3.20×10−4$3.20 \times {{10}^{ - 4}}$ for children and 0 to 4.29×10−4$4.29 \times {{10}^{ - 4}}$ for adults, which are higher than the acceptable limit of 1×10−4$1 \times {{10}^{ - 4}}$. These suggest that there are health concerns for adults and children in the research area. This necessitates the need for monitoring the soil in the study area to reduce potential environmental issues. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to compare the ability of five plant species, including (Conocarpus erectus, Acacia sensu lato (s.l.), Melaleuca viminalis, Dodonaea viscosa and Lantana camara) to absorb and accumulate heavy elements in their tissues, which were grown in the central islands in the city of Diwaniyah. This included areas of street in front of the medical college, Umm Al Khail First Street, Umm Al-Khail Street, near Abbas Attiwi Bridge, Al-Adly Street in the Euphrates District, and Clock Field Street, respectively. Results showed that soil samples S1 and S3 were contaminated by Pb, and the rest of the sites were contaminated with nickel only. This indicates through the table findings a rise in these heavy metals' concentrations with a rise in traffic momentum. Thus, the Pb concentrations in the growing plants' shoot parts with respect to this research had surpassed the allowed critical limit of 5.00 mg.kg-1 dry matter, in which the highest value was recorded at the site with respect to S3 as well as S2. Meanwhile, the findings indicate that Cd concentrations in S3 and S1 had increased and exceeded the allowable limit of 0.20 mg.kg-1 dry matter. In the meantime, the nickel concentrations were within the permissible limits of 67.90 mg.kg-1 dry matter. The Zn concentration exceeded the permitted limits of 60.00 mg.kg-1 dry matter except for plants (Acacia s.l. and Lantana camara) in sites S5 and S2. The results confirmed that the values of Heavy Metals Bioaccumulation Coefficient (BAC) for most of the study elements had recorded the highest value in the Dodonaea plant for Zn, Cd, and Pb, except for Ni. It was more accumulated in the Melaleuca viminalis plant, which indicates the superiority of the Dodonaea plant in accumulating Pb, Cd, and Zn over the rest of the study plants, as they took the following order: Lantana camara < Acacia s.l. < Conocarpus erectus < Melaleuca viminalis < Dodonaea viscosa. The best plants accumulated nickel in the following order: Acacia s.l. < Lantana camara < Conocarpus erectus < Dodonaea viscosa < Melaleuca viminalis. [ABSTRACT FROM AUTHOR]

Cereal crops account for a large proportion of human caloric demand for billions of people worldwide. However, harmful heavy metal accumulation in grain, i.e., cadmium (Cd), creates a widespread problem in threatening human health directly or indirectly through the food chain. In contrast to Cd, zinc (Zn)—an essential element chemically similar to Cd—is usually lower in concentration in consumed cereals than the amount needed to meet dietary needs, leading to malnutrition in many developing countries. As genetics and functional genomics data become increasingly available, a large body of studies has been conducted for Cd and Zn separately in different cereal crops, making it possible to perform a comparative analysis to reveal the shared or unique metal accumulation and transport mechanisms from genetic and genomics perspectives. Here, we reviewed recent efforts in dissecting the molecular mechanisms and genetic regulations regarding metal accumulation in cereal crops, mainly focusing on the two chemically similar metals—the toxic heavy metal Cd and the essential micronutrient Zn. Based on the literature study, we highlight a potential metal accumulation pathway that can be used as a benchmark to ascertain the functional roles of transporters across species to decrease Cd accumulation, increase Zn concentrations, and provide our view into the metal composition improvement in cereal crops. [ABSTRACT FROM AUTHOR]

Complexes formed between the heaviest and lightest elements in the periodic table yield the f-block hydrides, a unique class of compounds with wide-ranging utility and interest, from catalysis to light-responsive materials and nuclear waste storage. Recent developments in syntheses and analytics, such as exploiting low-oxidation state metal ions and improvements in X-ray diffraction tools, have transformed our ability to understand, access and manipulate these important species. This perspective brings together insights from binary metal hydrides, with molecular solution phase studies on heteroleptic complexes and gas phase investigations. It aims to provide an overview of how the f-element influences hydride formation, structure and reactivity including the sometimes-surprising power of co-ligands to tune their behaviour towards a variety of applications. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb) levels in dried chili peppers from nine districts in Guizhou Province. These heavy metals, widely dispersed and capable of transferring to crops, pose potential health risks to humans. The assessment included modeling daily intake (EDI), target hazard quotient (THQ), total target hazard index (TTHQ), and target carcinogenic risk (TCR) to assess health risks across different population groups. Results showed chromium (0.9540 ± 0.301 mg/kg) and lead (0.8949 ± 0.266 mg/kg) had the highest concentrations, followed by arsenic (0.3287 ± 0.093 mg/kg) and cadmium (0.0627 ± 0.017 mg/kg). Children exhibited higher EDI values than adults, indicating greater health risks from dried chili pepper consumption at equivalent levels. THQ and TTHQ values were below 1 across all regions, indicating no significant health risks associated with dried chili pepper consumption. Similarly, TCR values were below 10–4 for all nine regions, indicating an acceptable level of carcinogenic risk. Overall, consuming dried chili peppers in Guizhou Province poses an acceptable health risk, but caution is advised, especially for children, to limit heavy metal exposure. [ABSTRACT FROM AUTHOR]

Summary: Trace elements and heavy metals play pivotal roles in health status by regulating a myriad of vital biological functions. Abnormal metal homeostasis has been linked to a constellation of pathogenic complications, including oxidative stress, inflammatory processes, dyslipidemia, and impaired insulin‐mediated metabolism of carbohydrates, thereby increasing the odds of developing childhood obesity and related comorbidities. Herein, we provide a comprehensive revision of recent literature on the association between childhood obesity, trace elements, and heavy metals. Further, we emphasize on the crucial importance of addressing the influence that interindividual variability factors (e.g., sex, age, genetic determinants, concomitance of comorbidities, and environmental factors) may have in modulating the susceptibility to disease development. Altogether, this review article represents a concise guide to better understand the involvement of metals in childhood obesity pathogenesis and discusses future needs with the aim of establishing robust biomarkers in the context of precision medicine. [ABSTRACT FROM AUTHOR]

In this work, the role of spin‐orbit coupling (SOC) in the physical properties of TlBi2${\rm TlBi}_2$ is reported. These electronic calculations reveal that the heavy elements Tl and Bi promote strong spin‐orbit coupling, lifting some of the degeneracies at the high‐symmetry points. The presence of SOC causes significant decreases in both elastic constants and elastic moduli, which in turn improve the compatibility of the calculated Debye temperature (ΘD$\Theta _D$ = 80 K) with the recent experimental data of 83 K. Furthermore, our quasi‐static harmonic approximation calculation, like this elastic constant calculation, confirms that taking SOC into account improves agreement with the experiment by decreasing value of Debye temperature from 95 to 85 K. Activating the SOC causes significant modifications in the phonon spectrum and the density of phonon states, as well as in the Eliashberg spectral function. As a result of these modifications, the electron–phonon coupling parameter (λ$\lambda$) increases from 1.178 to 1.259, by ≈7%$\approx 7\%$. The calculated values of λ$\lambda$ both with and without SOC imply that TlBi2${\rm TlBi}_2$ can be treated as phonon‐mediated superconductor with strong coupling. The SOC‐induced increase in λ$\lambda$ brings the superconducting transition temperature of TlBi2${\rm TlBi}_2$ from 6.076 to 6.211 K, which is almost equal to the recent experimental value of 6.2 K. [ABSTRACT FROM AUTHOR]

In order to analyze the pollution characteristics and human health risks of heavy metals in water around Poyang Lake, 18 surface water samples were collected around Poyang Lake. The sources and distribution of heavy metals in water were analyzed, and the health risks of heavy metals in water were evaluated according to the risk assessment model of the United States Environmental Protection Agency (USEPA). The main cations of the water in the study area are Ca2+, and the anions are HCO3, SOf-- and Cl-. The hydrochemical genesis is mainly rock weathering and mineral hydrolysis, which is partly controlled by atmospheric precipitation. The average concentration of heavy metal elements in surface water is Fe>Ea>Mn〉Mo>Zn>Cu>Ni>Pb. Fe, Mo, Ni and Mn have different degrees of exceeding the standard, which mainly comes from fertilizer application, factory emissions and other activities. The HQder and HI>1 of Mo for children and adults, and the HQder and HI〉1 of Ba for children, it will causes great harm to human health. The study provides a scientific basis for the protection of water resources around Poyang Lake. [ABSTRACT FROM AUTHOR]

As a heavy metal element with great harm and heavy pollution in soil pollution, chromium (Cr) has posed a great threat to the soil environment and human living environment. Chromium mainly exists in the form of Cr(III) and Cr(VI) in the soil. It is of great significance to reduce Cr(VI) with strong toxicity and easy migration to Cr(III) with low toxicity and low migration. There are a large number of active groups in soil humus, which have a strong affinity with heavy metal ions and play an important role in the reduction of chromium. Humic substances are classified into three categories; however, fewer studies have been carried out simultaneously to investigate the functional groups involved in the reactions of humic acid (HA), fulvic acid (FA), and humic matter (HM) with Cr. In the present study, HA, FA, and HM were used to interact with Cr to investigate the mechanism of humus reduction of Cr(VI). The results showed the reducing ability of humic substances: HA > FA > HM. The functional groups that play a reducing role in humic substances are mainly carboxyl groups, ester groups, phenolic hydroxyl groups, and polysaccharides. The C=O and C—O bonds play a major role in the reduction of humus, but not all C=O and C—O bonds have changed during the reaction. The adsorption–reduction process was mainly carried out on the surface of humic substances, and Cr(III) was mainly adsorbed on humic substances with trace amounts of Cr(VI).7 [ABSTRACT FROM AUTHOR]

The traditional craft villages in Vietnam in general and in Bac Ninh province in particular have been exposing many negative impacts on the environment. The heavy metal-rich wastes from the metal recycling casting craft villages in the field of metal recycling and metal casting are causing severe heavy metal pollution not only to the air, soils, and sediments but also to the groundwater resources. In Da Hoi iron recycling craft village in Chau Khe ward, Tu Son town, Bac Ninh province, Vietnam, the Holocene aquifer is exposed to the Ngu Huyen Khe River's sediments contaminated with heavy metals Lead, Cadmium, Nickel, and Zinc. Freundlich isotherm parameters of the Holocene aquifer have been selected for finite element modeling of heavy metal transport with high temporal and spatial varying retardation factors to get reliable quantitative heavy metals' distribution in depth and time. Initial and boundary conditions have been augmented to be established. The retardation factors of the advection and dispersion transport in the Holocene aquifer for heavy metals Pb, Zn, Cd, and Ni are very highly none-linear and very much varying in time and space: 8.7–66.4 for Pb, 2.0–12 for Zn, 1.7–4.8 for Cd and 1.1–5.9 for Ni. The results of the numerical modeling show that heavy metal transport in the Holocene aquifer is very fast and the entire aquifer thickness has equilibrium aquifer formation and aquifer water heavy concentrations after around 2–2.5 years for Cd and Ni, around 4 years for Zn and around 27 years for Pb. The heavy metals' fluxes from the Holocene aquifer to the Pleistocene aquifer are maximal and more or less constant from the equilibrium time and would cause severe contamination of the Pleistocene aquifer. [ABSTRACT FROM AUTHOR]

Himalayan leucogranite is an excellent target for understanding the orogenic process of the India–Asia collision, but its origin and tectonic significance are still under debate. An integrated study of geochronology, geochemistry, and in situ Sr-Nd-Hf isotopes was conducted for a tourmaline-bearing leucogranite in the eastern Tethyan Himalaya using LA-ICP-MS, X-ray fluorescence spectroscopy, and ICP-MS and LA-MC-ICP-MS, respectively. LA-ICP-MS U-Pb dating of zircon and monazite showed that it was emplaced at ~19 Ma. The leucogranite had high SiO2 and Al2O3 contents ranging from 73.16 to 73.99 wt.% and 15.05 to 15.24 wt.%, respectively. It was characterized by a high aluminum saturation index (1.14–1.19) and Rb/Sr ratio (3.58–6.35), which is characteristic of S-type granite. The leucogranite was enriched in light rare-earth elements (LREEs; e.g., La and Ce) and large ion lithophile elements (LILEs; e.g., Rb, K, and Pb) and depleted in heavy rare-earth elements (e.g., Tm, Yb, and Lu) and high field strength elements (HFSEs; e.g., Nb, Zr, and Ti). It was characterized by high I Sr (t) (0.7268–0.7281) and low ε Nd (t) (−14.6 to −13.2) and ε Hf (t) (−12.6 to −9.47), which was consistent with the isotopic characteristics of the Higher Himalayan Sequence. Petrogenetically, the origin of the leucogranite is best explained by the decompression-induced muscovite dehydration melting of an ancient metapelitic source within the Higher Himalayan Sequence during regional extension due to the movement of the South Tibetan Detachment System (STDS). The significantly high lithium and beryllium contents of the leucogranite and associated pegmatite suggest that Himalayan leucogranites possess huge potential for lithium and beryllium exploration. [ABSTRACT FROM AUTHOR]

New petrological, geochemical, and P–T modelling results from igneous samples clarify how carbonatite‐lamprophyre magmatism, fluorite and rare earth element (REE) enrichment are petrogenetically related in southern Illinois. P–T modelling reveals that igneous rocks derive from a deep mantle carbonated source, that is consistent with trace element signatures for a fluorine‐rich transition zone origin. Major element systematics suggests liquid‐immiscibility with lamprophyric melts as the origin for Ca‐carbonatites. Heavy REE (HREE) enrichments in Hicks Dome breccias likely formed through preferential partitioning and transport of HREE by brine‐melts, exsolved from a deep carbonatite body. Brine‐melts redistributed HREEs throughout the system along brecciated pathways where they reprecipitated as HREE‐rich phosphate/fluorcarbonate minerals (e.g. xenotime, florencite, synchesite) in host bedrock. The diversity of igneous rocks in southern Illinois highlights the area as an excellent natural laboratory to study carbonated melt petrogenesis and evolution. [ABSTRACT FROM AUTHOR]

The highly sensitive detection of heavy metal elements in aqueous solution has been achieved by the combination of circular grooves and nanoparticle-enhanced laser-induced breakdown spectroscopy. The effects of Ag nanoparticles (Ag NPs) and circular grooves on the spectral emission of Cu, Pb and Cr have been investigated. The results show that both Ag NPs and circular grooves can enhance the spectral emission of heavy metal elements, and the circular grooves can improve the spectral reproducibility. The prepared micro/nanostructures can suppress the coffee ring effect and improve the absorption efficiency of light. The average relative standard deviation of the spectral emission can be diminished. By establishing calibration curves for Cu, Pb, and Cr elements, the limits of detection (LODs) for Cu, Pb and Cr elements have been obtained. The results show that by employing Ag NPs and circular grooves the lowest LOD of 0.10 mg mL-1 can be achieved. This improved spectral performance (spectral intensity, stability and detection sensitivity) originates mainly from the collective oscillation of free electrons of Ag NPs excited by the incident laser pulse, which confines the electromagnetic energy with a strongly enhanced electric field. The enhancement in electric field intensity of Ag NPs is calculated and the seed electron is proved to be predominantly excited through a multiphoton photoemission process under the experimental conditions. The results provide an efficient pathway for improving the detection sensitivity of heavy metals in aqueous solution. [ABSTRACT FROM AUTHOR]

Determining the controlling factors of the quality of groundwater can help decision-makers in preparing optimal management plans and a sustainable supply of water for drinking and agriculture. The results of factor analysis and hierarchical cluster analysis show that the chemical composition of groundwater in the Fereidan region (Iran) is controlled by both geogenic and anthropogenic factors. The natural background level of major variables and heavy metals including Cu, Zn, Hg, Cd, Pb, and As have been estimated using probabilistic and deterministic methods including the iterative 2σ outlier test, calculated distribution function (CDF), 95th percentile, and iterative Grubbs test (IGT). The results show that the pre-selection process and removal of outliers play a significant role in calculating NBLs and threshold values (TVs). Although heavy metals had different datasets and it was impossible to perform the pre-selection process for them, nevertheless, CDF, iterative 2σ, and 95th percentile methods were also used to calculate their NBLs. As the results show, Δ% between NBLs calculated by CDF, iterative 2σ, 95th percentile methods, and IGT is greater than that for complete datasets. This is because contaminated samples were not removed by the pre-selection process and some of these data remained in the final dataset. This shows itself as a skewed dataset of some heavy elements including Cu, Zn, and Cd. Therefore, if the goal is strict planning to take away the freedom of farmers and local planners to pollute the aquifer by providing smaller NBLs and TVs, it is better to use the smaller NBLs and TV determined by the IGT method after the pre-selection process. [ABSTRACT FROM AUTHOR]

There has been an increasing recognition of the efficacy of various clay mineral elements in absorbing heavy metallic ions, which can be attributed to their cost-effectiveness, widespread, precise floor area, and remarkable practical groups. A co-pyrolyzing calcite/biochar (CP-CAL/BC) composite was prepared in this study by co-pyrolyzing calcite (CP-CAL) and coconut shell (CS) at 650–750 °C. Several methods were employed to analyze the properties of the synthesized composite. The composite showed efficient adsorption of Pb2+ at a pH of 4.5, primarily by the process of monolayer chemisorption, which is influenced by the composite's pore structure and boundary layer diffusion. After several repeated experiments, it was observed that all of the CP-CAL/BC composites possessed exceptional regeneration capabilities, consistently removing Pb2+ at high rates. The CP-CAL/BC composite produced at 750 °C showed the greatest extent of resistance to corrosion, surpassing all other composites with a decrease in corrosion of 7.298 × 10−6 A/cm2. The present study confirmed that the CP-CAL/BC composite material has efficient adsorption features for Pb2+ and strong regenerative capability. Furthermore, the material synthesized at high temperatures demonstrated superior corrosion resistance. [ABSTRACT FROM AUTHOR]

Heavy metal accumulation in agricultural products has become a major concern. Previous studies have focused on the transport of heavy metals from the soil and their accumulation in crops. However, recent studies revealed that wheat leaves, ears, and awns can also transport and accumulate heavy metals. Wheat grains can be influenced by two sources of heavy metals: soil contamination and atmospheric deposition. To comprehend the transport characteristics of heavy metals in soil, atmospheric deposition, and wheat, 37 samples each for wheat rhizosphere soil, wheat roots, stems, leaves, and grains were collected. Fifteen samples of atmospheric dry deposition and atmospheric wet deposition were collected from Linshu County (northern area), China. Based on the test data, the characteristics of heavy metals and their distribution in the study area were analyzed. Migration patterns of heavy metals in crops from different sources were investigated using Pearson correlation and redundancy analysis. Finally, a predictive model for heavy metals in wheat grains was developed using multiple linear regression analysis. Significant disparities in the distribution of heavy metals existed among wheat roots, stems, leaves, and grains. The coefficient of variation of heavy metals in atmospheric deposition was relatively high, indicating discernible spatial patterns influenced by human activities. Notably, a positive correlation was observed between the concentration of heavy metals in wheat grains and atmospheric deposition of Hg, Cd, and Pb. Conversely, Zn and Ni levels in wheat grains were significantly negatively associated with soil Zn, Ni, pH, and OM content. The contribution of heavy metal elements from different sources varied in their impact on the grain's heavy metal content. Specifically, atmospheric deposition was the primary source of Hg and Pb in wheat grains, while Cd, Ni, Cu, and Zn were predominantly derived from soil. Using a multiple linear regression model, we could accurately predict Hg, Pb, Cd, Ni, Zn, and As concentrations in crop grains. This model can facilitate quantitative evaluation of ecological risk of heavy metals accumulation in crops in the study area. [ABSTRACT FROM AUTHOR]

The newly updated GIZMO and Simba based simulation, Simba-C , with its new stellar feedback, chemical enrichment, and recalibrated AGN feedback, allows for a detailed study of the intragroup medium X-ray properties. We discuss the impact of various physical mechanisms, e.g. stellar and AGN feedback, and chemical enrichment, on the composition and the global scaling relations of nearby galaxy groups. We also study the evolution (z = 2 to 0) of the global properties for the |$1\, \mathrm{keV}$| temperature groups. Simba-C shows improved consistent matching with the observations of all X-ray scaling relations compared to Simba. It is well known that AGN feedback has a significant influence on L X, 0.5–2.0– T spec, corr, S 500/2500– T spec, corr, and gas mass fractions, with our Simba-C results consistent with it. Our recalibrated AGN feedback strength also showed an additional improvement in gas entropy, which now aligns with CLoGS observations. The updated stellar feedback and chemical enrichment model is shown to play an important role in our understanding of the chemical abundance ratios and their evolution within galaxy groups. In particular, we find that Simba-C produces an increase in the amount of heavier elements (specifically Si and Fe) relative to O, compared to Simba. [ABSTRACT FROM AUTHOR]

π‐Conjugated compounds exhibit remarkable photophysical properties, such as strong light absorption and emission, and are applicable to organic devices, bioimaging, and sensing systems. The introduction of p‐block elements into π‐conjugated systems is presumable as a critical strategy for modulating their properties. Nevertheless, the type of utilized elements has been limited to the second and third‐period ones because it is difficult to construct critical electronic interactions between heavier atoms and carbon‐based π‐conjugated scaffolds. On the other hand, it has been recently suggested that the heavier p‐block elements are able to induce significant changes in the optoelectronic properties of π‐conjugated systems thanks to their large size, high polarizability, and heavy atom effect. Although there are much room to explore effects of heavy‐atom substitution on physical and electronic properties of conjugated systems, various characters have been discovered. Hence, this review mainly focuses on the relationships between the types of p‐block elements and the optical properties of their representative complexes and organoelement compounds, particularly light absorption and emission. [ABSTRACT FROM AUTHOR]

Time-domain and multimessenger astronomy (TDAMM) involves the study of transient and time-variable phenomena across various wavelengths and messengers. The Astro2020 Decadal Survey has identified TDAMM as the top priority for NASA in this decade, emphasizing its crucial role in advancing our understanding of the universe and driving new discoveries in astrophysics. The TDAMM community has come together to provide further guidance to funding agencies, aiming to define a clear path toward optimizing scientific returns in this research domain. This encompasses not only astronomy but also fundamental physics, offering insights into properties of gravity, the formation of heavy elements, the equation of state of dense matter, and quantum effects associated with extreme magnetic fields. Magnetars, neutron stars with the strongest magnetic fields in the universe, play a critical role in this context. We aim to underscore the significance of magnetars in TDAMM, highlighting the necessity of ensuring observational continuity, addressing current limitations, and outlining essential requirements to expand our knowledge in this field. [ABSTRACT FROM AUTHOR]

Context. About 25–50% of white dwarfs are found to be contaminated by heavy elements, which are believed to originate from external sources such as planetary materials. Elemental abundances suggest that most of the pollutants are rocky objects and only a small fraction of white dwarfs bear traces of volatile accretion. Aims. In order to account for the scarcity of volatile pollution, we investigate the role of the white dwarfs' magnetospheres in shielding the volatile content of icy objects. Methods. We estimated the volatile sublimation of inward drifting exocomets. We assume the orbits of the exocomets are circularized by the Alfvén wing drag that is effective for long-period comets. Results. Volatile material can sublimate outside the corotation radius and be shielded by the magnetic field. The two conditions for this volatile-shielded mechanism are that the magnetosphere radius must be larger than the corotation radius and that the volatiles are depleted outside the corotation radius, which requires a sufficiently slow orbital circularization process. We applied our model to nine white dwarfs with known rotational periods, magnetic fields, and atmosphere compositions. Our volatile-shielded model may explain the excess of volatile elements such as C and S in the disk relative to the white dwarf atmosphere in WD2326+049 (G29-38). Nevertheless, given the sensitivity of our model to the circularization process and material properties of icy objects, there remains considerable uncertainty in our results. Conclusions. We emphasize the importance of white dwarfs' magnetic fields in preventing the accretion of volatile gas onto them. Our work suggests a possible explanation for the scarcity of volatile-accretion signatures among white dwarfs. We also identify a correlation between the magnetic field strength, the spin period, and the composition of pollutants in white dwarf atmospheres. However, given the uncertainties in our model, more observations are necessary to establish more precise constraints on the relevant parameters. [ABSTRACT FROM AUTHOR]

Aims. Recent simulations have shown that asymmetries in the ejecta distribution of supernova remnants (SNRs) may be a reflection of asymmetries left over from the initial supernova explosion. Thus, SNR studies provide a vital means for testing and constraining model predictions in relation to the distribution of heavy elements, which are key to improving our understanding of the explosion mechanisms in Type Ia supernovae. Methods. The use of a novel blind source separation method applied to the megasecond X-ray observations of the historic Kepler and Tycho supernova remnants has revealed maps of the ejecta distribution. These maps are endowed with an unprecedented level of detail and clear separations from the continuum emission. Our method also provides a three-dimensional (3D) view of the ejecta by individually disentangling red- and blueshifted spectral components associated with images of the Si, S, Ar, Ca, and Fe emission. This approach provides insights into the morphology of the ejecta distribution in those two remnants. Results. Those mappings have allowed us to thoroughly investigate the asymmetries in the intermediate-mass elements and Fe distribution in two Type Ia supernova remnants. We also compared the results with the core-collapse Cassiopeia A remnant, which we had studied previously. The images obtained confirm, as expected for Type Ia SNRs, that the Fe distribution is mostly closer to the core than that of intermediate-mass elements. They also highlight peculiar features in the ejecta distribution, such as the Fe-rich southeastern knot in Tycho. [ABSTRACT FROM AUTHOR]

Aims. It is now well established that a large amount of heavy (trans-iron) elements are produced during neutron star (NS) mergers. These elements can be detected in the spectra of the kilonova emitted from the post-merger ejected materials. Due to the high level densities that characterize the complex configurations belonging to heavy elements, thus giving rise to millions of absorption lines, the kilonova ejecta opacity is of significant importance. The elements that contribute the most to the latter are those with an unfilled nd subshell belonging to the fifth and the sixth rows of the periodic table, and those with an unfilled nf subshell belonging to the lanthanide and actinide groups. The aim of the present work is to make a new contribution to this field by performing large-scale atomic structure calculations in three specific sixth-row 5d elements, namely hafnium, osmium, and gold, in the first four charge stages (I–IV), and by computing the corresponding opacities, while focusing on the importance of the atomic models used. Methods. The pseudo-relativistic Hartree–Fock (HFR) method, including extended sets of interacting configurations, was used for the atomic structure and radiative parameter calculations, while the expansion formalism was used to estimate the opacities. Results. Theoretical energy levels, wavelengths, and oscillator strengths were computed for millions of spectral lines in Hf I–IV, Os I–IV, and Au I–IV ions, the reliability of these parameters being assessed through detailed comparisons with previously published experimental and theoretical results. The newly obtained atomic data were then used to calculate expansion opacities for typical kilonova conditions expected one day after the NS merger; these are a density of ρ = 10−13 g cm−3 and temperatures ranging from T = 5000 K to T = 15 000 K. Some agreements and differences were found when comparing our results with available data, highlighting the importance of using sufficiently complete atomic models for the determination of opacities. [ABSTRACT FROM AUTHOR]

The chemistry of light dipnictenes has been widely investigated in the last century with remarkable achievements especially for azobenzene derivatives. In contrast, distibenes and dibismuthenes are relatively rare and show very limited reactivity. Herein, we have designed a protocol using visible light to enhance the reactivity of heavy dipnictenes. Exploiting the distinctive π–π* transition, we have been able to isolate unique examples of dipnictene‐cobalt complexes. The reactivity of the distibene complex was further exploited using red light in the presence of a diazoolefin to access an unusual four‐membered bicyclo[1.1.0]butane analog, containing only a single carbon atom. These findings set the bases to a conceptually new strategy in heavy element double bonds chemistry where visible light is at the front seat of bond activation. [ABSTRACT FROM AUTHOR]

Observations of AT2017gfo, the counterpart of the double neutron star merger, confirmed the existence of kilonovae that are suggested to originate from the decay of the very heavy elements. However, the different simplified assumptions used in analytical and semi-analytical models can lead to a variety of fitting results. Previous semi-analytical models have assumed a grey body because of the challenge in calculating the detailed opacity of ejecta and to save the calculation time. However, the variation of opacity with wavelength cannot be ignored when calculating the multicolour flux. Though numerical simulations can calculate kilonova details, they require an excessive amount of time for data modelling. In this work, we propose an extension of previous semi-analytical models by not assuming the grey-body opacity and constant thermalization efficiency assumptions. We demonstrate that the impact of opacity changing with wavelength is non-negligible and then introduce an empirical analytical opacity in optical and near-infrared bands to calculate multicolour light curves of kilonovae with a three-dimensional, three-component model. Additionally, we consider the evolution of thermalization efficiency at later times, enabling application of our model to both the early and later phases of kilonovae. To enable efficient fitting of models with many parameters (23 parameters in the case of double neutron star merger), a quick method based on the greedy algorithm is developed. We can well reproduce the infrared/optical/ultraviolet observations of AT2017gfo. This model can also be extended to black-hole and neutron star mergers as well. [ABSTRACT FROM AUTHOR]

Two organic carbon resources (wood ash and sawdust) were applied in the study site to assess their profound effects on soil properties and growth and biomass properties of lupin (Lupinus albus L.). Because of their contribution to improving soil structure, enhanced water-holding capacity, and increased carbon sequestration. The experiments were conducted in mid-November 2022 at Grdarasha Research Station, College of Agricultural Engineering Sciences, Salahaddin University-Erbil, Iraq. The experiment includes two organic amendments (wood ash and sawdust) as a treatment and Control. Results showed that the application of wood ash and sawdust improved and raised the number of essential elements and heavy metals in the soil, which in turn boosted the ability of the roots to absorb nutrients. The highest germination percentage, plant height, and leaf number were observed in the ash treatment (95.00 %, 22.00 cm, and 21.22) respectively. The great values of fresh and dry shoot weight were found in sawdust treatment 63.78 and 14 g/plant) respectively. The effects of treatments were not significant on root length and fresh and dry root weights. The final findings showed that adding various forms of organic carbon could alter the chemical characteristics of the soil. This, in turn, might have a good impact on microbes, which can subsequently help plants grow by converting, solubilizing, and mobilizing soil nutrients. Furthermore, lupin plants appeared to be a form of phytoremediation, or absorption, for certain heavy metals. [ABSTRACT FROM AUTHOR]

Honey represents the reflection of the surrounding environment and it is used as a biomarker for pollutants in the environment. It is noteworthy and necessary that the food be free of heavy metals and toxic compounds. In this research, a comprehensive survey of essential and non-essential elements along with heavy metals was carried out for honey samples collected from honey-rich areas in Iraqi Kurdistan region. The biochemical properties of honey and 20 elements were studied. The honey samples showed pH values ranged between (3.66 – 7.05 ), acidity (9 – 35 meq/kg), moisture percent (12-16.1% ), conductance ( 0.203 – 1.063 mS/m), diastase enzyme activity ( 11.1 - 65 IU), HMF (1.46 – 48 ) and the average of sugar content ( 3.14, 27.2, 39.2, and 77.8) for sucrose, glucose, fructose and total sugar percentage, respectively. The mean values of the analyzed elements (Pb, Sb, As, Zn, Cu, Ni, Co, Fe, Mn, Cr, V, Ti, Mg, Al, Sr, Ba, Cd, Se, Mo and Be) were (0.050, 0.037, 0.005, 0.916, 1.096, 0.257, 0.034, 6.977, 1.232, 2.309, 1.355, 0.033, 0.0, 74.803, 61.565, 1.300, 0.178, 0.008, 0.366 and 0.039 mg/kg), respectively. A single sample from Erbil governorate showed a high quantity of aluminum, and the highest value for Pb was found in honey samples from Sulaymaniyah governorate. Additionally, the highest concentration of all the other important nutrients was detected in Sulaymaniyah honey samples. The final findings demonstrated that the honey from Kurdistan region is not contaminated with heavy metals (HM) and contains sufficient essential nutrients that are necessary to human health, supporting the high quality of the region’s honey [ABSTRACT FROM AUTHOR]

Despite the increased brilliance of the new generation synchrotron sources, there is still a challenge with high‐resolution scanning of very thick and absorbing samples, such as a whole mouse brain stained with heavy elements, and, extending further, brains of primates. Samples are typically cut into smaller parts, to ensure a sufficient X‐ray transmission, and scanned separately. Compared with the standard tomography setup where the sample would be cut into many pillars, the laminographic geometry operates with slab‐shaped sections significantly reducing the number of sample parts to be prepared, the cutting damage and data stitching problems. In this work, a laminography pipeline for imaging large samples (>1 cm) at micrometre resolution is presented. The implementation includes a low‐cost instrument setup installed at the 2‐BM micro‐CT beamline of the Advanced Photon Source. Additionally, sample mounting, scanning techniques, data stitching procedures, a fast reconstruction algorithm with low computational complexity, and accelerated reconstruction on multi‐GPU systems for processing large‐scale datasets are presented. The applicability of the whole laminography pipeline was demonstrated by imaging four sequential slabs throughout an entire mouse brain sample stained with osmium, in total generating approximately 12 TB of raw data for reconstruction. [ABSTRACT FROM AUTHOR]

Various chemical properties and some heavy elements of wastewater discharged from Tikrit Teaching Hospital were studied during the period of October to December 2023. Some chemical properties were measured, such as pH, total hardness, calcium and magnesium hardness in addition to biological and chemical requirements. Compared to the Iraqi water standards, considering the biological and chemical requirements, an increase was recorded in most values of oxygen, pH and some heavy elements such as lead, cadmium, copper, and iron. For the total hardness and the hardness of calcium, magnesium, and chloride, they were within the Iraqi water standards. These results show that hospitals are the main source of excreta that must be taken into consideration before any action strategy to assess environmental and health threats. The quantity and type of toxins and liquid excreta produced from hospital operations pose a danger to living organisms in general, particularly humans. In many developing countries, liquid waste from hospitals is often disposed directly into the environment, such as by discharging it into rivers without treatment. [ABSTRACT FROM AUTHOR]

Objective: Exposure to heavy metals has been reported to be associated with impaired cognitive function, but the underlying mechanisms remain unclear. This pilot study aimed to identify key heavy metal elements associated with cognitive function and further explore the potential mediating role of metal‐related DNA methylation. Methods: Blood levels of arsenic, cadmium, lead, copper, manganese, and zinc and genome‐wide DNA methylations were separately detected in peripheral blood in 155 older adults. Cognitive function was evaluated using the Mini‐Mental State Examination (MMSE). Least absolute shrinkage and selection operator penalized regression and Bayesian kernel machine regression were used to identify metals associated with cognitive function. An epigenome‐wide association study examined the DNA methylation profile of the identified metal, and mediation analysis investigated its mediating role. Results: The MMSE scores showed a significant decrease of 1.61 (95% confidence interval [CI]: −2.64, −0.59) with each 1 standard deviation increase in ln‐transformed arsenic level; this association was significant in multiple‐metal models and dominated the overall negative effect of 6 heavy metal mixture on cognitive function. Seventy‐three differentially methylated positions were associated with blood arsenic (p < 1.0 × 10−5). The methylation levels at cg05226051 (annotated to TDRD3) and cg18886932 (annotated to GAL3ST3) mediated 24.8% and 25.5% of the association between blood arsenic and cognitive function, respectively (all p < 0.05). Interpretation: Blood arsenic levels displayed a negative association with the cognitive function of older adults. This finding shows that arsenic‐related DNA methylation alterations are critical partial mediators that may serve as potential biomarkers for further mechanism‐related studies. ANN NEUROL 2024;96:87–98 [ABSTRACT FROM AUTHOR]

The South China Block, a region renowned for its extensive granite distribution and rich metal deposits, serves as a natural laboratory for the study of granite-related mineralization. This research focuses on the Tongtianmiao granite pluton, which is located at the intersection of the Qin-Hang and Nanling metallogenic belts and has been confirmed as a significant lithium mineral resource. Despite its discovery and ongoing development, the lithium-rich Tongtianmiao pluton has been understudied, particularly concerning its petrogenesis, which has only recently come to the forefront of scientific inquiry. By integrating an array of petrogeochemical data with geochronological studies derived from zircon and monazite dating, this study provides insights into the magmatic processes related to lithium enrichment in the Tongtianmiao granites. The Tongtianmiao granites are classified as A-type granites characterized by high SiO2 contents (69.18–78.20 wt.%, average = 74.08 wt.%), K2O + Na2O contents (4.59–8.34 wt.%, average = 6.86 wt.%), A/CNK > 1.2, and low concentrations of Ca, Mg, and Fe. These granites are enriched in alkali metals such as Li, Rb, and Cs but are significantly depleted in Ba, Sr, and Eu. They show no significant fractionation of light or heavy rare-earth elements but present characteristic tetrad effects. A finding of this study is the identification of multiple ages from in situ zircon U–Pb dating, which implies a prolonged history of magmatic activity. However, given the high uranium content in zircons, which could render U–Pb ages unreliable, emphasis is placed on the monazite U–Pb ages. These ages cluster at approximately 172.1 ± 1.1 Ma and 167.9 ± 1.6 Ma, indicating a Middle Jurassic period of granite formation. This timing correlates with the retreat of the Pacific subduction plate and the associated NE-trending extensional fault activity, which likely provided favorable conditions for lithium enrichment. The study concluded that the Tongtianmiao granites were formed through partial melting of crustal materials and subsequent underplating by mantle-derived materials, and were contaminated by strata materials. This process resulted in the formation of highly differentiated granite through magmatic differentiation and external forces. These findings have significant implications for understanding the petrogenesis of lithium-rich granites and are expected to inform future exploration endeavors in the Tongtianmiao pluton. [ABSTRACT FROM AUTHOR]

Over the past decades, environmental radionuclide research using innovative X-ray spectroscopy techniques in combination with other analytical/spectroscopic methods and quantum chemical and atomistic modelling has helped improve scientific understanding of radiochemical processes important for numerous application areas and secure basic knowledge of relativistic (many electron) heavy elements. Examples of x-ray absorption and fluorescence spectroscopic techniques applied to a range of 4f/5f element systems are presented which aim to demonstrate the evolution in the field. [ABSTRACT FROM AUTHOR]

Monte Carlo simulations are commonly used to model the behavior of chemical species of the heaviest elements and their homologs in gas chromatography experiments. In this paper, we present an extension of the fundamental Monte Carlo simulation proposed by Zvara in 1985. While preserving the core functionality, our code features two enhancements: first, it allows simulating experiments in which a primary radioisotope decays into a daughter isotope belonging to a different element, hence exhibiting different chemical properties. Second, it allows modeling scenarios where conversion of an initial chemical species to a different one can occur at temperatures high enough to overcome an activation barrier, facilitating simulations of related physisorption and chemisorption processes. This Monte Carlo code is applicable to open tubular and rectangular chromatography columns. [ABSTRACT FROM AUTHOR]

Rheological behavior can be used to characterize the multilevel composite agglomerates of cultivated soil for perennial sugarcane in South China. The intrinsic parameters, particle size distribution, and cohesive properties of soil were obtained using various physical and mechanical experiments, such as soil density, moisture content, clay particle size gradation screening, angle of repose and triaxial compression. According to the distribution of particle size within the ranges of different tillage depth and the Hertz Mindlin with JKR particle contact model, a systematic simulation was conducted on the angle of repose under clay flow. The contact factors were also screened and calibrated by the Plackett-Burman, the steepest climb and the Box-Behnken test. A multilayer model with nonhomogeneous discrete element was constructed using agglomerate geometric and mechanical properties. The discrete element parameters of heavy clay were used to explore the quantitative agglomerate generation, settling, platen undermining and layered stacking. According to the geometric composition of unsaturated soil particles and parameter assignments, such as JKR, the rheological constitutive behavior of soil was verified using the coupled triaxial compression on RecurDyn-EDEM. The rheological model of cane field tillage was verified to predict the tillage performance, and then to analyze the propulsion resistance of bionic wall plate. The angle of repose and soil triaxial compression showed that the JKR surface energy, coefficient of recovery and kinetic friction factor of the soil were the significant influencing factors on the rheological response of the heavy clay soil, with the contribution rates of 48.24%, 30.09% and 7.80%, respectively. The measured angles of repose of the soil materials in different layers were used as the objective for optimization. The optimal solution of contact parameter was calibrated to evaluate the differences of the parameters among the different layers of the cultivated field. There was the similar between the simulated and experimental stacking shape for the angle of repose using the optimal calibration parameters, where the prediction error of angle was less than 1.67%. The discrete element model was contained the agglomerate gradation distribution, intrinsic contact and cohesive properties. The composite rheological properties of multi-till layers were characterized to obtain the intrinsic response deviation. The triaxial behavioral error was less than 9.27%. The relative error was only 8.3% between the calculated using this model and the measured of propulsion resistance of the bionic wall plate. The error was within the acceptable range, indicating the effective and accurate prediction of the interaction relationship between the machine tool and the soil material. The finding can also provide the data support and model reference for the adaptive design and dynamic optimization of contact soil components. [ABSTRACT FROM AUTHOR]

Phosphoric acid-activated geopolymer has become a promising ceramic material due to its superior thermal and mechanical properties. However, the gradual shortage of phosphate resources and the high price of phosphoric acid will be the key factors limiting the wide application of phosphoric acid-activated geopolymers. This paper developed a low-cost and low-carbon geopolymer non-sintered ceramics using industrial waste acid. The compressive strength of the prepared specimens can reach 32.2 MPa. The thermal gravimetric analysis indicated that the mass loss of the geopolymer remained almost unchanged in the temperature range between 400 and 1500 °C, indicating the geopolymer exhibited excellent thermal stability. Additionally, the infiltration test showed that the majority of the heavy metals could be solidified successfully with over 90% solidification efficiency, meaning the leaching of the heavy metals into the environment can be well controlled. Finally, the environmental and economic analysis showed that the carbon intensity (kg/m3/MPa) was reduced by 92.7% and 57.7% compared to cement paste and reported geopolymer. The cost intensity ($/m3/MPa) was negative due to the income of waste acid treatment, meaning that additional value benefit was added to the product. This paves a promising way for producing low-cost and low-carbon ceramic materials with excellent thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

A total of 121 PM2.5 samples were collected in Chengguan District of Lanzhou during non-heating period (June 1, 2022 - August 31, 2022) and heating period (November 1, 2022 - January 31, 2023), and the pollution characteristics, sources and health risks of 14 elements were investigated. The results showed that the average PM2.5 concentration ((44.1±12.2) μg/m³) in the heating period was about twice that in the non-heating period ((20.8±3.05) μg/m³). The average concentration of 14 elements in PM2.5 in heating period ((4 443±953) ng/m³) was much higher than that in non-heating period ((2 854±426) ng/m³), among which Al, Ca, Fe, Cu and K were the main elements in PM2.5 in Lanzhou City. The results of enrichment factor analysis and positive matrix factorization showed that 14 heavy metal elements in PM2.5 were mainly from the mixed sources (soil dust, biomass combustion and industrial emissions) (39.1%), followed by industrial emissions (23.3%), traffic emissions (20.2%) and coal combustion emissions (17.4%). Health risk assessment results showed that Cr had the highest carcinogenic risk among all carcinogenic elements, and there were carcinogenic risks for adult males, adult females and children in non-heating period and heating period. Mn had non-carcinogenic risks for adult males, adult females and children in heating period. Therefore, the emission of Cr and Mn in PM2.5 needs to arouse the high attention of relevant departments, and certain measures should be taken for emission reduction supervision of coal combustion and industrial production such as electroplating, metallurgy, tanning and building construction that produce these two elements. The total carcinogenic risk and total non-carcinogenic risk were in the order of children > adult males > adult females. [ABSTRACT FROM AUTHOR]

With the rapid development of industrialization and urbanization, the issue of soil environmental pollution is becoming more and more prominent, especially concerning heavy metal contamination, which has garnered significant scholarly attention. The surface watershed formed by waterline is influenced by various factors such as topography, industrial emissions, and agricultural runoff, resulting in a complex process of migration and accumulation of heavy metal elements from multiple sources. In this study, the pollution characteristics and sources of heavy metal elements Hg, As, Pb, Ni, Cd, Cr, Cu and Zn in 165 surface soil samples from the Manghe River watershed in Jiyuan City were comprehensively analyzed using a variety of methods, including statistics, geostatistics, enriched factor analysis and the Positive Matrix Factorization Model (PMF). The results showed that the concentrations of Hg, Cd, As, Cu, Pb and Zn exceeded their corresponding background values with varying degrees of enrichment. Notably, the average contents of Cd, Hg and Pb were 26.70 times, 3.69 times and 4.49 times higher than those in Chinese soils on average, respectively, showing obvious enrichment characteristics. Moreover, there were distinct spatial distribution patterns for each heavy metal element; Ni and Cr exhibited similar trends mainly controlled by the parent material, while human activities significantly affect the other six elements forming high-value areas around mining and related industries. It is noteworthy that Cu, Hg and Zn were influenced by dominant wind direction in autumn and winter, forming sub-high-value zones in southern forested areas; meanwhile, Cu and Zn were also influenced by agricultural fertilizer application as well as surface runoff, leading to secondary high-value areas in the dryland areas. Further analysis revealed a significant positive correlation among these heavy metal elements, suggesting that they may share common sources. Through the PMF Model, four main factors were identified, with factor 2 (36.25%), factor 1 (23.00%), factor 3 (21.20%) and factor 4 (19.55%) ranked in descending order of contribution rate. The heavy metal pollution in the study area was attributed to anthropogenic activities and natural factors, accounting for 63.75% and 36.25%, respectively. Coal mining, chemical industry smelting, vehicle emissions and excessive use of agrochemicals were identified as the main sources of heavy metal pollution. These pollutants entered the soil through direct emissions, atmospheric deposition, transportation and agricultural activities, exerting a significant impact on the soil environment. Therefore, delving into the spatial distribution pattern of soil heavy metal pollution and precise analysis of its sources are of great importance for effective treatment and remediation of soil heavy metal pollution in small watersheds, maintaining healthy soil ecology and safeguarding human health. [ABSTRACT FROM AUTHOR]

Soil environmental quality related to the residents' life, health, and safety, has been the hotspot issues in science of ecological environment protection. Evaluating the distribution characteristics, ecological risk, and source of heavy metals in farmland is important for protecting soil resources. The agricultural area of Lianhua town, Gongcheng County, Guilin is a typical karst landform. In response to the problem of heavy metal pollution and complex sources in the soil of this area, the characteristics and sources of heavy metal pollution in the soil profiles from farmland, abandoned land, and forest were studied using the single-factor index method, the geoaccumulation index (Igeo) principal component analysis (PCA) and positive matrix factorization (PMF) model. The results showed that: (1) that the contents of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in the soil profile of the study area were higher than that of the soil elements background values in Guangxi. The total and available forms contents of all heavy metal elements exhibited the characteristics of accumulation in the surface profile; (2) among the six heavy elements, the contents of Cd were in a moderately to heavily polluted state. The contents of Cd in some soil profiles exceeded the control standard for agricultural land soil pollution. The contents of Zn and Ni were from slightly to moderately polluted in areas with frequent agricultural activities; (3) according to the PCA and PMF model, there were three main sources of heavy metals in the study area. Among them, Cd, Cu, Ni, and Zn are related to agricultural activities; the elements As, Cd, Cr, and Hg are closely related to geological background; Pb and Zn are mainly affected by atmospheric sedimentation of transportation. Agricultural activities and natural geological background are the main contribution sources of heavy metals in soil. Human activities are the main factors that cause the accumulation of heavy metals in soil. This research has theoretical guidance and practical significance for the prevention and control of soil heavy metal pollution and the protection of farmland environmental quality in the region. [ABSTRACT FROM AUTHOR]