Changes In Element Concentrations Research Articles

[Pollution Characteristics, Source, and Health Risk Assessment of Metal Elements in PM2.5 Between Winter and Spring in Zhengzhou].

A total of 18 metal elements in ambient PM2.5 in Zhengzhou were continuously determined using an online heavy metal observation instrument in January and April, 2021, and the changes in element concentrations were analyzed. Metal elements were traced via enrichment factors, positive matrix factorization (PMF), and a characteristic radar chart. The US EPA health risk assessment model was used to assess the health risks of heavy metals, and the backward trajectory method and the concentration-weighted trajectory (CWT) method were used to evaluate the potential source regions of health risks. The results showed that the element concentrations were higher in spring, and the sum of Fe, Ca, Si, and Al concentrations accounted for 89.8% and 87.5% of the total element concentrations in winter and spring, respectively. Cd was enriched significantly, which was related to human activities. The concentrations of Pb, Se, Zn, Ni, Sb, and K in winter and Cr, Ni, Fe, Mn, V, Ba, Ca, K, Si, and Al in spring increased with the increasing pollution level. The results of PMF and the characteristic radar chart showed that the main sources of metal elements in winter and spring were industry, crust, motor vehicles, and mixed combustion, with industry and mixed combustion pollution occurring more often in winter and crust pollution occurring more often in spring. Significant non-carcinogenic risks existed in both winter and spring with more severe health risks in winter, and Mn caused significant non-carcinogenic risks. The health risks in winter were mainly influenced by Zhengzhou and surrounding cities and long-distance transport in the northwest, and the health risks in spring were mainly influenced by Zhengzhou and surrounding cities.

Trace Elements in Alzheimer's Disease and Dementia: The Current State of Knowledge.

Changes in trace element concentrations are being wildly considered when it comes to neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. This study aims to present the role that trace elements play in the central nervous system. Moreover, we reviewed the mechanisms involved in their neurotoxicity. Low zinc concentrations, as well as high levels of copper, manganese, and iron, activate the signalling pathways of the inflammatory, oxidative and nitrosative stress response. Neurodegeneration occurs due to the association between metals and proteins, which is then followed by aggregate formation, mitochondrial disorder, and, ultimately, cell death. In Alzheimer's disease, low Zn levels suppress the neurotoxicity induced by β-amyloid through the selective precipitation of aggregation intermediates. High concentrations of copper, iron and manganese cause the aggregation of intracellular α-synuclein, which results in synaptic dysfunction and axonal transport disruption. Parkinson's disease is caused by the accumulation of Fe in the midbrain dopaminergic nucleus, and the pathogenesis of multiple sclerosis derives from Zn deficiency, leading to an imbalance between T cell functions. Aluminium disturbs the homeostasis of other metals through a rise in the production of oxygen reactive forms, which then leads to cellular death. Selenium, in association with iron, plays a distinct role in the process of ferroptosis. Outlining the influence that metals have on oxidoreduction processes is crucial to recognising the pathophysiology of neurodegenerative diseases and may provide possible new methods for both their avoidance and therapy.

Hydrothermal alteration of the surface volcanic rocks at the Acoculco geothermal field, Mexico: a multi-parametric approach

AbstractThe studies on hydrothermal alteration-induced effects in surface and subsurface rocks provide useful information in the characterization and exploitation of a geothermal reservoir. Generally, these studies are based on traditional, and reliable methods like petrography (primary and secondary minerals, and grade of alteration), and geochemistry (mobility of elements, changes in mass and concentration of elements, and fluid inclusions). Recently, apart from these established methods, some methods based on the geochemical (Chemical Index of Alteration, CIA; Weathering Index of Parkar, WIP; Loss on Ignition, LOI; and Sulfur, S) and rock magnetic properties (magnetic susceptibility, χlf; and percentage frequency-dependent susceptibility, χfd%) are also being applied in the identification of whether a rock is an altered or a fresh one. The Acoculco Geothermal Field (AGF), Mexico, is characterized by high temperature and very low permeability, and it is considered a promissory Enhanced Geothermal System. The following changes are observed in the rocks as a result of an increase in hydrothermal alteration: (1) an increase in CIA, LOI, and S values, and a decrease in WIP; (2) an increase in quartz and quartz polymorph minerals (silicification), and clay minerals (argillization); and (3) decrease in χlf values. At AGF, the most altered surface acid rocks are characterized by entirely quartz and its polymorphs, and clay minerals. The present study also indicates the applicability of the binary plots of major elements (felsic vs mafic component) and rock magnetic parameters (χlf vs. χfd%). The rock with χfd% value of 2–10 and χlf value < 0.5 × 10–6 m3 kg−1 indicate the presence of single domain and stable single domain grains, which in turn suggests that it is an altered rock. These methods are simple to apply, rapid, reliable, and have the potential to become effective tools for the identification of hydrothermally altered rocks during the initial stage of geothermal exploration.

Experimental study on the micro-mechanical parameters of Ni-based single-crystal superalloys using nanoindentation and element distribution analysis

Ni-based single-crystal superalloys are normally prepared by directional solidification. Due to different solidification sequences, Ni-based single-crystal superalloys exhibit a typical dendritic arm structure, and the element segregation in the dendritic arm can affect the high temperature mechanical properties of the alloy. Solid solution treatment has a certain extent to reduce the inter-dendritic and dendritic arm between the concentrations of the elements, thereby changing the alloy micro-nano view parameters to improve the high temperature mechanical properties of the alloy. In this study, nanoindentation experiments were carried out on the inter-dendritic and dendritic arm of the cast and solid solution samples. The micromechanical parameters were calculated. The amounts of changes in elemental concentration were discussed with the results of the energy dispersive spectroscopy and electron probe microanalysis, so as to analyse the relationship between the micromechanical parameters and the changes in elemental concentration. The results show that solid solution treatment has a significant impact on the elastic modulus, with an increase of 114.7% of the inter-dendritic region and an increase of 142.7% of the dendritic arm. However, solid solution treatment has little effect on the hardness, with no significant change in the hardness of the inter-dendritic region and an increase of 43.86% of the dendritic arm. Solid solution treatment has a more significant effect on improving the segregation behavior of Al and Co elements, with the segregation coefficients of Al and Co elements in the inter-dendritic region decreasing and increasing by 36% and 19%, and the segregation coefficients of Al and Co elements in the dendritic arm region decreasing and increasing by 29% and 34%.

Serum trace elements during treatment in pancreatic cancer patients and their associations with cancer prognosis

Background & AimsIn this study, we assessed serum trace element concentrations in patients with pancreatic cancer and compared the results to those of healthy controls and patients with chronic pancreatitis. We evaluated the association between trace element concentrations during cancer treatment and the risk of cancer progression and mortality in pancreatic cancer patients. MethodsA retrospective cohort study was conducted at a tertiary center in Korea. Serum trace element concentrations of cobalt (Co), copper (Cu), selenium (Se), and zinc (Zn) were measured at diagnosis using an inductively coupled plasma-mass spectrometry in 124 pancreatic cancer patients, 50 chronic pancreatitis patients, and 120 healthy controls. Trace elements were measured after a median of 282.5 (95% confidence interval [CI], 224.0–326.5) days from treatment initiation to assess changes in trace element concentrations during treatment. ResultsSerum Co and Cu concentrations were significantly higher in patients with chronic pancreatitis and pancreatic cancer than in healthy controls, while serum Se and Zn concentrations were significantly lower. During treatment, serum concentrations of Cu, Se, and Zn were significantly decreased in patients with pancreatic cancer.During the follow-up (median 152.5; 95% CI, 142.8–160.0 months), 85.5% of patients experienced progression or relapse, and 84.7% of patients died. Patients with decreased Se and Zn concentrations during treatment had a higher mortality (hazard ratio [HR], 2.10; 95% CI, 1.31–3.38; P = 0.0020 for Se; HR, 1.72; 95% CI, 1.06–2.79; P = 0.0269 for Zn) compared to those with unchanged or increased trace element concentrations during treatment. Patients with a greater reduction in Zn concentrations during treatment had a higher mortality than those with a smaller reduction (HR, 1.59; 95% CI, 1.01–2.52; P = 0.0483). Patients whose Zn status changed to deficient after treatment had an increased mortality (HR, 1.76; 95% CI, 1.16–2.67, P = 0.0084). Patients with multiple (≥ 2) trace element deficiencies after treatment had poorer outcomes than those with no or single trace element deficiency. ConclusionsThis study revealed that decreases in Se and Zn concentrations during cancer treatment were associated with adverse outcomes in terms of cancer progression and mortality in patients with pancreatic cancer. Further prospective investigations are recommended.

Analysis of Dynamic Wear Characteristics of Joint Contact Friction Pair of Excavators Working Device

The working device of an excavator in construction machinery is prone to damage and wear under ordinary working conditions. Based on a model of an excavator under typical working conditions, the dynamic load-bearing situation of the three main joint friction subsets of the working device is simulated by using the virtual prototype technology; the location of the functional device with high stress is identified based on finite element analysis, and the correctness of the simulation results is verified by designing strain gauges. Based on this, the dynamic contact stress variation law of the contact surface of the end-face friction subsets was explored, and the end-face wear depth was calculated by combining Archard wear theory and finite element wear simulation technology; the specimens were worn on the end-face wear tester, and the surface wear was observed under the scanning electron microscope to summarize the wear mechanism and analyze the element content changes of the worn surface. The results show that the three main joints of the working device produce large dynamic fluctuations and are prone to wear, and the destructive degree is more prominent; the wear process is accompanied by higher temperatures, fatigue wear, and abrasive wear on the wear surface, and the wear depth value of the right end face is significantly larger than that of the left end face. This method has a significant reference value for reliability analysis and optimization improvement when using construction machinery’s main joint friction pairs.

Improvement of mid-wave infrared quantum cascade laser epitaxy by studying the effect of thermal annealing on GaInAs/AlInAs superlattice

GaInAs/AlInAs superlattice play an important role in the epitaxial structure of mid-wave infrared quantum cascade lasers. This paper find the optimal deoxidation temperature point for an InP/Ga0.31In0.69As/Al0.64In0.36As quantum cascade laser (QCL) epitaxial process combining MBE (for active cores) and MOCVD (for waveguide cladding) co-growth, and investigate the effect of thermal annealing on this superlattice. Comprehensive multi-technical analysis including atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) confirmed that slow annealing of the structure at a temperature of 480 °C can be properly optimized. The crystal quality and surface smoothness were confirmed, and the changes in element content of the ternary alloy under thermal reaction were analyzed. These results provide an extremely effective reference value for the QCL secondary epitaxial waveguide layer.

The detection of elemental content changes in electrode coating using laser-induced breakdown spectroscopy

The elemental content of battery electrode coating is prone to change due to the production technology and ambient factors. To ensure the consistent performance and safety of a lithium battery, the elemental content of the electrode coating needs to be kept strictly consistent. This study proposes an internal mixed matrix method that combines laser-induced breakdown spectroscopy and chemometric method to achieve rapid and accurate detection of elemental content changes in electrode coating. The stoichiometric ratios of analytical elements are calculated by using the spectra of laser-induced breakdown spectroscopy. The relationships between that stoichiometric ratios and the actual content of analytical elements are studied and show that they are linear. Thus, the content change of the analytical element can be determined by calculating the change of the stoichiometric ratio. The average relative errors for content changes of iron, lithium, and phosphorus are 6.43%, 2.96%, and 4.12%, respectively, and the lowest detection limits are 278.2 mg/kg, 20.5 mg/kg, and 105.4 mg/kg, respectively. Furthermore, the internal reference method is proposed to correct the effect of ambient gases and improve detection accuracy. The results are that when Fe I 372.751 nm and Fe I 373.485 nm are used as analytical lines, after correcting for the effect of ambient gases, the average relative errors of Fe content changes are reduced by 62% and 72%, respectively, and the lowest detection limits are increased by 67% and 71%, respectively.

The arsenic-lowering effect of inulin-type prebiotics in end-stage renal disease: a randomized crossover trial.

Background: Circulatory imbalance of trace elements is frequent in end-stage renal disease (ESRD), leading to a deficiency of essential elements and excess of toxic elements. The present study aimed to investigate whether inulin-type fructans (ITFs) could ameliorate the circulatory imbalance by modulating gut microbiota and regulating the absorption and elimination of trace elements. Methods: Peritoneal dialysis patients were enrolled in a randomized crossover trial, undergoing interventions with ITFs (10 g d-1) and maltodextrin (placebo) over a 9-month period (with a 3-month washout). The primary outcomes included essential elements Mn, Fe, Co, Cu, Zn, Se, Sr, and Mo and potential toxic elements V, Cr, Ni, As, Cd, Ba, Tl, Pb, Th, and U in plasma. Secondary outcomes included the gut microbiome, short chain fatty acids (SCFAs), bile acids (BAs), and daily removal of trace elements through urine, dialysate and feces. Results: Among the 44 participants initially randomized, 29 completed the prebiotic, placebo or both interventions. The daily dietary intake of macronutrients and trace elements remained consistent throughout the study. The administration of 10 g d-1 ITFs significantly reduced plasma arsenic (As) by 1.03 μg L-1 (95%CI: -1.74, -0.33) (FDR-adjusted P = 0.045) down from the baseline of 3.54 μg L-1 (IQRs: 2.61-4.40) and increased the As clearance rate by urine and dialysis (P = 0.033). Positive changes in gut microbiota were also observed, including an increase in the Firmicutes/Bacteroidetes ratio (P = 0.050), a trend towards higher fecal SCFAs (P = 0.082), and elevated excretion of primary BAs (P = 0.035). However, there were no significant changes in plasma concentrations of other trace elements or their daily removal by urine, dialysis and feces. Conclusions: The daily administration of 10 g d-1 ITFs proved to be effective in reducing the circulating retention of As but demonstrated to be ineffective for other trace elements in ESRD. These sentences are ok to include but as "The clinical trial registry number is ChiCTR-INR-17013739 (https://www.chictr.org.cn/showproj.aspx?proj=21228)".

The mechanism of NOx removal in the sintering process based on source reduction of carbon emissions.

This study systematically investigates the mechanism of NOx emissions during the sintering process, with a focus on the utilization of biochar as an auxiliary fuel to replace a portion of the coke traditionally used in iron ore sintering. The research involved the simulation of sintering raw material ratios using iron ore, biochar, and coke powder. Substitution levels of biochar for coke were set at 0%, 20%, 40%, 50%, 60%, 80%, and 100%. NOx emissions during the sintering process were monitored using a sintering flue gas detection system. Simultaneously, a comprehensive analysis of the sintered ore was conducted with the aim of producing samples that meet sintered ore requirements while reducing NOx emissions. Experimental results revealed that when biomass charcoal substitution for coke reached 50%, the lowest NO emissions were observed during the sintering process, with a reduction of over 90% in accumulated NO emissions in the exhaust gas. In this process, due to the participation of biochar, CO2 emissions were reduced by approximately 50% compared to traditional sintering processes. The study also analyzed the physicochemical properties of the sintered ore using methods such as XRD, Raman, FTIR, and Vickers hardness testing. The results indicated that the hardness fluctuated within the range of 610 to 710N for sintered products with different levels of biochar substitution, and there were minimal changes in Fe element content and crystal phase transformations.

Apatite geochemical composition of Mesozoic granitoids in the eastern Jiangnan Orogen, S. China: insights into petrogenesis and intrinsic magmatic variables

ABSTRACT The geochemical compositions of apatite are commonly used to provide reliable constraints on the intrinsic magmatic variables of the parental magma. There is a widespread distribution of Mesozoic granitic rocks in the eastern Jiangnan Orogen (EJNO), which include I-type and A-type granitoids. This study aims to investigate the geochemical composition of apatite in 11 representative I-type and A-type granitic intrusions from the EJNO to understand their petrogenesis, intrinsic magmatic variables, and polymetallic mineralization potential. The results show that apatites in these granitoids were characterized by oscillatory zonation and homogeneous texture, and exhibited high F, and low Cl contents, as well as high REE, Y, and Th contents, indicating magmatic origin. These apatites were divided into two groups depending on their geochemical characteristics and original rock types. In Group I apatites (in the I-type granitoids), the absence of an abrupt change in major and trace element concentrations from the core to the rim of the apatite crystals, combined with their low levels of MgO, Sr, and HREY (HREE+Y), serves as evidence to classify the I-type granitoids as low Sr-Y adakitic granitoids with a low Mg#, which can be attributed to the partial melting of the thickened lower crust. In Group A apatites (in the A-type granites), the normal increase in incompatible elements from the core to the rim, as well as the presence of a flat REE pattern with pronounced Eu anomalies, can be attributed to crystal fractionation of plagioclase, allanite, and zircon. Furthermore, Group I apatites have higher SO3, Cl, and molar OH/F and Cl/F ratios compared to Group A apatites. Quantitative calculation by apatite-melt partitioning and modelling suggests that the I-type granitic magmas were more volatile-rich and more oxidized than A-type granitic magmas. Taken together, based on the relationship between the intrinsic magmatic variables and the behaviour of ore-forming elements, our study demonstrates that early I-type granitoids of the EJNO have a strong W-Mo-Cu polymetallic mineralization potential, while late A-type granites may possess rare metal mineralization potential.

Borocarbonitride-Based Emerging Materials for Supercapacitor Applications: Recent Advances, Challenges, and Future Perspectives.

Supercapacitors have emerged as a promising energy storage technology due to their high-power density, fast charging/discharging capabilities, and long cycle life. Moreover, innovative electrode materials are extensively explored to enhance the performance, mainly the energy density of supercapacitors. Among the two-dimensional (2D) supercapacitor electrodes, borocarbonitride (BCN) has sparked widespread curiosity owing to its exceptional tunable properties concerning the change in concentration of the constituent elements, along with an excellent alternative to graphene-based electrodes. BCN, an advanced nanomaterial, possesses excellent electrical conductivity, chemical stability, and a large specific surface area. These factors contribute to supercapacitors' overall performance and reliability, making them a viable option to address the energy crisis. This review provides a detailed survey of BCN, its structural, electronic, chemical, magnetic, and mechanical properties, advanced synthesis methods, factors affecting the charge storage mechanism, and recent advances in BCN-based supercapacitor electrodes. The review embarks on the scrupulous elaboration of ways to enhance the electrochemical properties of BCN through various innovative strategies followed by critical challenges and future perspectives. BCN, as an eminent electrode material, holds great potential to revolutionize the energy landscape and support the growing energy demands of the future.

Mercury and selenium concentrations in lanugo of free-ranging California sea lions in the southern Gulf of California, Mexico

Total mercury ([THg]) and selenium ([TSe]) concentrations were determined in California sea lion (Zalophus californianus) lanugo from the Gulf of California in 2021 and 2022. Relationships with sex, morphometrics, and year were evaluated. Following toxicological thresholds of concern for piscivorous mammals, most pups had a [THg] < 10 ppm, one pup (2021) had a [THg] > 20 ppm, no pups had a [THg] > 30 ppm. Females had significantly higher [TSe] than males; sex did not influence [THg]. [THg] and [TSe] in 2022 were significantly higher in the general population and male cohorts compared to 2021. Significant negative correlations were observed between [THg], [TSe], and morphometrics (2021). These results indicate that, compared to other pinniped species, regional California sea lions may have a decreased likelihood of experiencing Hg-related adverse health effects. Year-related changes in element concentrations suggest continued monitoring of this population to assess pinniped, environmental, and potentially, human health.

Multidimensional characterization of Ni-Zn ferrite films based on laser-induced breakdown spectroscopy technology

Existing experimental results have suggested that doping different elements will significantly affect the properties of the thin film produced using the target material. In this study, the properties of the film were studied under different powers and different pressures through the magnetron sputtering method of preparation of three elements containing nickel, zinc, and iron thin film. First, the film is subjected to laser-induced breakdown spectroscopy (LIBS) detection, and the obtained spectral data are processed to obtain the energy spectrum and two-dimensional (2D) distribution of the elements. Next, the film thickness was examined under a scanning electron microscope (SEM) to verify the feasibility of LIBS technology in film thickness measurement. Another set of experiments was performed to estimate the film thickness based on the obtained data to determine the accuracy of film thickness measurement using LIBS technology. Subsequently, the transmittal rate and energy-dispersive X-ray spectroscopy (EDS) of the thin film that was obtained by the sputtering of Nickel-zinc ferrite film were examined. The optical band gap of the thin film was determined following the transmittal rate of the thin film. Besides, the variation trend of the optical band gap was plotted and then compared with the LIBS spectral data. The statistical data of the element proportion were obtained through EDS, and the calibration curve was generated in combination with the LIBS spectral data. As revealed by the above-mentioned results, the LIBS is capable of analyzing the change of element content in the binary doped thin films.

Failure Study of BFRP Joints with Two Epoxy Adhesives under Hygrothermal Coupling.

Basalt Fibre Reinforced Polymer (BFRP)-bonded structures are lightweight, high strength, economical, and environmentally friendly, which is very advantageous in the civil sector. The aim of this paper is to provide a comprehensive account of the hygrothermal degradation and failure mechanisms of BFRP-bonded structures by comparing the residual properties of two epoxy adhesive BFRP single-lap joints after ageing for 240 h, 480 h, and 720 h in an extreme hygrothermal environment with pure water at 80 °C. The hydrophilicity and thermal stability of the two adhesives were firstly compared by water absorption and Thermogravimetric Analysis (TGA) tests, and the hygrothermal degradation of the molecular chains and the reduction in Tg were characterised by Fourier Transform Infra-Red (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC) curves. The failure strength and load-displacement curves of the two joints were then compared, and it was found that the strength and stiffness had different trends, while the paired t-test was used to demonstrate the correlation between the failure strength and the adhesive Tg, as well as the difference in the failure mechanisms of the two joints caused by the water absorption rate. The analysis of macrosections and Scanning Electron Microscope (SEM) images summarised the process and reasons for the transition of the failure mode from fibre tearing to hybrid failure, and finally, the changes in elemental concentration and O/C values were analysed by Energy Dispersive X-ray Analysis (EDX), which proved that the degree of hydrolysis could not be used as a judgement of the degradation degree of the joint alone, and provided data support for the application of the BFRP-bonded structure in the humid and hot environment.

Contributions of CO2, O2, and H2O to the Oxidative Stability of Solid Amine Direct Air Capture Sorbents at Intermediate Temperature.

Aminopolymer-based sorbents are preferred materials for extraction of CO2 from ambient air [direct air capture (DAC) of CO2] owing to their high CO2 adsorption capacity and selectivity at ultra-dilute conditions. While those adsorptive properties are important, the stability of a sorbent is a key element in developing high-performing, cost-effective, and long-lasting sorbents that can be deployed at scale. Along with process upsets, environmental components such as CO2, O2, and H2O may contribute to long-term sorbent instability. As such, unraveling the complex effects of such atmospheric components on the sorbent lifetime as they appear in the environment is a critical step to understanding sorbent deactivation mechanisms and designing more effective sorbents and processes. Here, a poly(ethylenimine) (PEI)/Al2O3 sorbent is assessed over continuous and cyclic dry and humid conditions to determine the effect of the copresence of CO2 and O2 on stability at an intermediate temperature of 70 °C. Thermogravimetric and elemental analyses in combination with in situ horizontal attenuated total reflection infrared (HATR-IR) spectroscopy are performed to measure the extent of deactivation, elemental content, and molecular level changes in the sorbent due to deactivation. The thermal/thermogravimetric analysis results reveal that incorporating CO2 with O2 accelerates sorbent deactivation using these sorbents in dry and humid conditions compared to that using CO2-free air in similar conditions. The in situ HATR-IR spectroscopy results of PEI/Al2O3 sorbent deactivation under a CO2-air environment show the formation of primary amine species in higher quantity (compared to that in conditions without O2 or CO2), which arises due to the C-N bond cleavage at secondary amines due to oxidative degradation. We hypothesize that the formation of bound CO2 species such as carbamic acids catalyzes C-N cleavage reactions in the oxidative degradation pathway by shuttling protons, resulting in a low activation energy barrier for degradation, as probed by metadynamics simulations. In the cyclic experiment after 30 cycles, results show a gradual loss in stability (dry: 29%, humid: 52%) under CO2-containing air (0.04% CO2/21% O2 balance N2). However, the loss in capacity during cyclic studies is significantly less than that during continuous deactivation, as expected.

Chronic drought alters extractable concentrations of mineral elements in Mediterranean forest soils

Soil mineral elements play a crucial role in ecosystem productivity and pollution dynamics. Climate models project an increase in drought severity in the Mediterranean Basin in the coming decades, which could lead to changes in the composition and concentrations of mineral elements in soils. These changes can have significant impacts on the fundamental processes of plant-soil cycles. While previous studies have predominantly focused on carbon, nitrogen, and phosphorus, there is a notable lack of research on the biogeochemical responses of other mineral elements to increasing drought. In this study, we investigated the effects of chronic drought (15 years of experimental rainfall exclusion) and seasonal drought (summer period) on the extractable soil concentrations of 17 mineral elements (arsenic (As), calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), sulphur (S), strontium (Sr), vanadium (V) and zinc (Zn)) in a Mediterranean holm oak forest. We also explored the potential biotic and abiotic mechanisms underlying the changes in extractable elemental concentrations under chronic drought conditions. Our findings reveal that soil elemental concentrations varied significantly due to seasonal changes and chronic drought, with soil microclimate, biological activity, and organic matter being the main drivers of this variability. Levels of soil water content primarily explained the observed variations in soil elemental concentrations. Most of the mineral elements (13 out of 17) exhibited higher concentrations during winter-spring (wet seasons) compared to summer-autumn (dry seasons). The chronic drought treatment resulted in K limitation, increasing vegetation vulnerability to drought stress. Conversely, the accumulation of S in soils due to drought may intensify the risk of S losses from the plant-soil system. Under drought conditions, certain trace elements (particularly Mn, V, and Cd) exhibited increased extractability, posing potential risks to plant health and the exportation of these elements into continental waters. Overall, our results suggest that alterations in mineral element concentrations under future drier conditions could promote ecosystem degradation and pollution dispersion in the Mediterranean Basin. Understanding and predicting these changes are essential for effective ecosystem management and mitigating the potential negative impacts on plant health and water quality.

Assessing Microplastic-Induced Changes in Sandy Soil Properties and Crop Growth

An ever-increasing amount of microplastics enters the environment and affects soil properties and plant growth. Investigating how the interactions between microplastics and soil properties vary across different soil types is crucial. In sandy soil, the subcritical SWR induced by microplastics may affect other soil properties. The objective of this study was to assess the impact of adding three types of microplastics (high-density polyethylene, polyvinyl chloride, and polystyrene) at a concentration of 5% (w/w) to sandy soil on the persistence and severity of SWR, as well as on various soil properties (bulk density, water sorptivity, and hydraulic conductivity) and plant characteristics (fresh and dry weight, maximum photochemical efficiency of PSII, and nutrient content) of radish (Raphanus sativus L.). It was found that microplastic contamination increased the persistence and severity of SWR and decreased soil bulk density, water sorptivity, and hydraulic conductivity. The total biomass measurements did not reveal a significant difference between the microplastic treatments and the control group. This study did not confirm any significant influence of microplastic contamination on the maximum photochemical efficiency of PSII, a measure of crop photosynthesis. Even though the value of photosynthetic efficiency changed with time, the values for all treatments stabilised at the end of the experiment. Microplastic contamination did not significantly alter crops’ nitrogen, phosphorus, potassium, or zinc contents. However, the copper content was reduced in all treatments, and magnesium and iron were reduced in the PVC and PS treatments compared to the control. The microplastic-induced changes in biomass or photosynthetic efficiency do not correspond to the changes in crop element concentrations.

Dynamics of trace and rare earth elements during long-term (over 4 years) decomposition in Scots pine and Norway spruce forest stands, Southern Sweden

The temporal dynamics of 33 major, trace, and rare earth elements (REEs) were studied in the litter samples containing Swedish Norway spruce (Picea abies) (NSL) and Scots pine (Pinus sylvestris) (SPL), with the aim to assess their release and accumulation dynamics. Litter bags (8 × 8 cm) were incubated in paired monoculture stands with both the species for up to 5 years from 1979 to 1984 according to a randomized block design comprising 25 blocks (1 × 1 m) within an area of 625 m2. The decomposition rate was slightly higher for Scots pine litter (k = 0.315) than for Norway spruce litter (k = 0.217). During litter decomposition, at ∼70% accumulated mass loss (AML), the concentration of trace elements increased by &amp;gt;50% in both litter types compared to initial concentrations. The concentration change took place in a non-linear pattern, and polynomial quadratic regression between concentration change and accumulated mass loss resulted in significant relationships (adj R2 = 0.20–0.97; p = 0.15–&amp;lt;0.0001). The changes in concentration and amount of trace elements resulted in two main types of dynamics: 1) both concentration and amount increased for Fe, Al, Ti, Cu, Mo, V, Zr, Sb, As, Cs, Pb, Th, and U; 2) concentration increased but amount decreased for Ni, Zn, Li, and Sr. The amount of REEs increased from ∼3-fold to 99-fold from the beginning to the end of incubation, suggesting accumulation during litter decomposition. The dynamics of different REEs were similar in their change patterns in the two litters. Different REEs had generally identical change patterns during incubation, which is reflected in the high correlations among them (r2 = &amp;gt;0.95). A general upward convexity in the dynamics suggests that if further incubated in the field, decomposing litter could have accumulated more REEs in the organic matter. The results of this study can be useful for future studies in other ecosystems including metal-contaminated sites or element-depleted sites. Plant litter accumulation, its decomposition, and build-up of humic substances in the decomposing organic matter can act as a sink for elements and can be used as a management tool for ecological amelioration of metal-contaminated sites as well as natural systems that are impoverished, especially recuperating sites. The study’s findings have implications beyond such sites and can be useful in any research that seeks to understand the patterns of accumulation and release related to decomposition in different ecosystems.

Thermodynamic Calculation of 2618 High Performance Aluminum Alloy

The thermodynamic-related physical parameters, precipitation amount of equilibrium phase, and initial precipitation temperature of Al-(1.9–2.5) Cu-(1.2–1.8) Mg-(0.9–1.5) Fe-(0.9–1.5) Ni alloy were simulated by using the thermodynamic simulation software JMat-Pro. The results show that with the change of element content, the liquidus temperature is in the range of 641.92–638 °C. The precipitation transition temperature of the eutectic phase with a low melting point ranges from 515 °C to 517.25 °C. The solidus temperature is closely related to Cu/Mg. The dendrite spacing decreases with the increase of Mg and Fe (Ni) contents, among which Mg has the greatest influence, followed by Fe (Ni) and Cu. The partial molar Gibbs free energy of Cu, Mg, Fe, and Ni is negative. The activity of Mg increases with the decrease in temperature, and the maximum activity is 0.10189, while the activities of Cu, Fe, and Ni are close to 0. The initial precipitation temperatures of S(Al2CuMg) and Al9FeNi phases are 424–450 °C and 635.4–643.01 °C, respectively. The initial precipitation temperature of the Al9FeNi phase decreases with the increase of Cu and Mg contents, while it increases with the increase of Fe (Ni) contents. With the increase of Cu and Mg contents, the initial precipitation temperature of S(Al2CuMg) increases and decreases with the increase of Fe (Ni) contents. The precipitation amount of S(Al2CuMg) mainly depends on the content and ratio of Cu and Mg, while that of Al9FeNi increases with the increase of Fe and Ni elements in the same proportion.