Human molybdenum exposure risk in industrial regions of China: New critical effect indicators and reference dose.

Evidence increasingly suggests molybdenum exposure at environmental levels is still associated with adverse human health, emphasizing the necessity to establish a more protective reference dose (RfD). Herein, we conducted a study measuring 15 urinary metals and 30 clinical health indicators in 2267 participants residing near chemical enterprises across 11 Chinese provinces to investigate their relationships. The kidney and cystatin-C emerged as the most sensitive organ and critical effect indicator of molybdenum exposure, respectively. Odds of cystatin-C-defined chronic kidney disease (CKD) in the highest quantile of molybdenum exposure significantly increased by 133.5% (odds ratio [OR]: 2.34, 95% CI: 1.78, 3.11) and 75.8% (OR: 1.76, 95% CI: 1.24, 2.49) before and after adjusting for urinary 14 metals, respectively. Intriguingly, cystatin-C significantly mediated 15.9-89.5% of molybdenum's impacts on liver and lung function, suggesting nephrotoxicity from molybdenum exposure may trigger hepatotoxicity and pulmonary toxicity. We derived a new RfD for molybdenum exposure (0.87 µg/kg-day) based on cystatin-C-defined estimated glomerular filtration rate by employing Bayesian Benchmark Dose modeling analysis. This RfD is significantly lower than current exposure guidance values (5-30 µg/kg-day). Remarkably, >90% of participants exceeded the new RfD, underscoring the significant health impacts of environmental molybdenum exposure on populations in industrial regions of China.

Construction of Models To Predict the Effectiveness of E-Waste Control through Capture of Volatile Organic Compounds and Metals/Metalloids Exposure Fingerprints: A Six-Year Longitudinal Study.

The significant health implications of e-waste toxicants have triggered the global tightening of regulation on informal e-waste recycling sites (ER) but with disparate governance that requires effective monitoring. Taking advantage of the opportunity to implement e-waste control in the Guiyu ER since 2015, we investigated the temporal variations in levels of oxidative DNA damage, 25 volatile organic compound metabolites (VOCs), and 16 metals/metalloids (MeTs) in urine in 918 children between 2016 and 2021 to demonstrate the effectiveness of e-waste control in reducing population exposure risks. The hazard quotients of most MeTs and levels of 8-hydroxy-2'-deoxyguanosine in children decreased significantly during this time, indicating that e-waste control effectively reduces the noncarcinogenic risks of MeT exposure and levels of oxidative DNA damage. Using mVOC-derived indexes as a feature, a bagging-support vector machine algorithm-based machine learning model was constructed to predict the extent of e-waste pollution (EWP). The model exhibited excellent performance with accuracies >97.0% in differentiating between slight and severe EWP. Five simple functions established using mVOC-derived indexes also had high accuracy in predicting the presence of EWP. These models and functions provide a novel human exposure monitoring-based approach for assessing e-waste governance or the presence of EWP in other ERs.

Why Do People Gain Belly Fat in Rural Areas? A Study of Urinary Metal(loid)s and Abdominal Obesity in China.

Obesity is prevalent in rural areas of China, and there are inconsistent findings regarding the association between metal(loid) exposure and the risk of obesity. Abdominal obesity (AOB), which reflects visceral fat abnormity, is a crucial factor in studying obesity-related diseases. We conducted a study measuring 20 urinary metal(loid)s, 13 health indicators, and the waist circumference (WC) in 1849 participants from 10 rural areas of China to investigate their relationships. In the single exposure models, we found that urinary chromium (Cr) was significantly associated with the odds of having AOB [adjusted odds ratio (OR) = 1.81 (95% confidence interval (CI): 1.24, 2.60)]. In the mixture exposure models, urinary Cr consistently emerged as the top contributor to AOB, while the overall effect of mixed metal(loid)s was positive toward the odds of having AOB [adjusted OR: 1.33 (95% CI: 1.00, 1.77)], as revealed from the quantile g-computation model. After adjusting for the effects of other metal(loid)s, we found that the elevation of apolipoprotein B and systolic blood pressure significantly mediated the association between urinary Cr and the odds of having AOB by 9.7 and 19.4%, respectively. Our results suggest that exposure to metal(loid)s is a key factor contributing to the prevalence of AOB and WC gain in rural areas of China.

Embedment of Multiple Transition Metal Impurities into WS2 Monolayer for Bandstructure Modulation.

Band structure by design in 2D layered semiconductors is highly desirable, with the goal to acquire the electronic properties of interest through the engineering of chemical composition, structure, defect, stacking, or doping. For atomically thin transition metal dichalcogenides, substitutional doping with more than one single type of transition metals is the task for which no feasible approach is proposed. Here, the growth of WS2 monolayer is shown codoped with multiple kinds of transition metal impurities via chemical vapor deposition controlled in a diffusion-limited mode. Multielement embedment of Cr, Fe, Nb, and Mo into the host lattice is exemplified. Abundant impurity states thus generate in the bandgap of the resultant WS2 and provide a robust switch of charging/discharging states upon sweep of an electric filed. A profound memory window exists in the transfer curves of doped WS2 field-effect transistors, forming the basis of binary states for robust nonvolatile memory. The doping technique presented in this work brings one step closer to the rational design of 2D semiconductors with desired electronic properties.

Trace copper detection using in-line optical fiber Mach-Zehnder interferometer combined with an optoelectronic oscillator.

We experimentally demonstrate a novel optical fiber chemosensor for trace Cu2+ ions detection that is implemented by using an in-line optical fiber Mach-Zehnder interferometer (MZI) in conjunction with an optoelectronic oscillator (OEO). The MZI is fabricated by lateral offset splicing a section of D-shaped fiber between two single-mode fibers. It splices the broadband optical source into a sinusoidal-shaped light, which can form a single passband microwave photonic filter (MPF) by combining the Mach-Zehnder modulator, a segment of fiber and a photodetector. The center frequency of the MPF, determined by the free spectra range of MZI, is affected by the solution concentration. Incorporating the MPF in the OEO sensor, the oscillation frequency is determined by the solution concentration. Therefore, we can estimate the solution concentration by measuring the microwave frequency change. We carry out a proof to concept experiment. High sensitivity Cu2+ ions concentration sensing with sensitivity of 13 Hz/(µM/L) is achieved. The maximum measurement error of concentration obtained is within 1.38 µM/L. The proposed sensor has merits of high interrogation speed, simple operation, high sensitivity and accuracy, offering the potentials in a wide range of biological application scenarios.

Exposure to synthesized tribromobisphenol A and critical effects: Metabolic pathways, disease signature, and benchmark dose derivation.

2,2',6-Tribromobisphenol A (Tri-BBPA), the main debrominated congener of tetrabromobisphenol A (TBBPA), is ubiquitous in the environment and human body but with unknown toxicity. Tri-BBPA was synthesized and applied to investigate its sub-chronic exposure effects on 28 organ coefficients and clinical health indicators related to liver function, kidney function, and cardiovascular system function in female mice. Results showed that the liver was the targeted organ of Tri-BBPA exposure. Compared to the control group, the changes in liver coefficient, cholinesterase, total protein, albumin, γ-glutamyl transpeptidase, lactate dehydrogenase, and creatine kinase levels ranged from -61.2 % to 35.5 % in the high-exposed group. Creatine kinase was identified as a critical effect indicator of Tri-BBPA exposure. Using the Bayesian benchmark dose derivation method, a lower reference dose than TBBPA was established for Tri-BBPA (10.6 µg/kg-day). Serum metabolomics revealed that Tri-BBPA exposure may primarily damage the liver by disrupting tryptophan metabolism related to L-alanine, tryptamine, 5-hydroxyindoleacetic acid, and 5-methoxyindoleacetate in liver cells and leading to liver dysfunction. Notably, epilepsy, schizophrenia, early preeclampsia, and late-onset preeclampsia were the top six enriched diseases, suggesting that the nervous system may be particularly affected by Tri-BBPA exposure. Our findings hinted a non-negligible health risk of exposure to debrominated products of TBBPA.

Perturbation of lipid metabolism in 3T3-L1 at different stages of preadipocyte differentiation and new insights into the association between changed metabolites and adipogenesis promoted by TBBPA or TBBPS.

Tetrabromobisphenol A (TBBPA) and tetrabromobisphenol S (TBBPS) are widely distributed brominated flame retardants. While TBBPA has been demonstrated to stimulate adipogenesis, TBBPS is also under suspicion for potentially inducing comparable effects. In this study, we conducted a non-targeted metabolomics to examine the metabolic changes in 3T3-L1 cells exposed to an environmentally relevant dose of TBBPA or TBBPS. Our findings revealed that 0.1 µM of both TBBPA and TBBPS promoted the adipogenesis of 3T3-L1 preadipocytes. Multivariate analysis showed significant increases in glycerophospholipids, sphingolipids, and steroids relative levels in 3T3-L1 cells exposed to TBBPA or TBBPS at the final stage of preadipocyte differentiation. Metabolites set composed of glycerophospholipids was found to be highly effective predictors of adipogenesis in 3T3-L1 cells exposed to TBBPA or TBBPS (revealed from the receiver operating characteristic curve with an area under curve > 0.90). The results from metabolite set enrichment analysis suggested both TBBPA and TBBPS exposures significantly perturbed steroid biosynthesis in adipocytes. Moreover, TBBPS additionally disrupted the sphingolipid metabolism in the adipocytes. Our study presents new insights into the obesogenic effects of TBBPS and provides valuable information about the metabolites associated with adipogenesis induced by TBBPA or TBBPS.

Alkali metal bilayer intercalation in graphene.

Alkali metal (AM) intercalation between graphene layers holds promise for electronic manipulation and energy storage, yet the underlying mechanism remains challenging to fully comprehend despite extensive research. In this study, we employ low-voltage scanning transmission electron microscopy (LV-STEM) to visualize the atomic structure of intercalated AMs (potassium, rubidium, and cesium) in bilayer graphene (BLG). Our findings reveal that the intercalated AMs adopt bilayer structures with hcp stacking, and specifically a C6M2C6 composition. These structures closely resemble the bilayer form of fcc (111) structure observed in AMs under high-pressure conditions. A negative charge transferred from bilayer AMs to graphene layers of approximately 1~1.5×1014 e-/cm-2 was determined by electron energy loss spectroscopy (EELS), Raman, and electrical transport. The bilayer AM is stable in BLG and graphite superficial layers but absent in the graphite interior, primarily dominated by single-layer AM intercalation. This hints at enhancing AM intercalation capacity by thinning the graphite material.

A high-precision jujube disease spot detection based on SSD during the sorting process.

The development of automated grading equipment requires achieving high throughput and precise detection of disease spots on jujubes. However, the current algorithms are inadequate in accomplishing these objectives due to their high density, varying sizes and shapes, and limited location information regarding disease spots on jujubes. This paper proposes a method called JujubeSSD, to boost the precision of identifying disease spots in jujubes based on a single shot multi-box detector (SSD) network. In this study, a diverse dataset comprising disease spots of varied sizes and shapes, varying densities, and multiple location details on jujubes was created through artificial collection and data augmentation. The parameter information obtained from transfer learning into the backbone feature extraction network of the SSD model, which reduced the time of spot detection to 0.14 s. To enhance the learning of target detail features and improve the recognition of weak information, the traditional convolution layer was replaced with deformable convolutional networks (DCNs). Furthermore, to address the challenge of varying sizes and shapes of disease spot regions on jujubes, the path aggregation feature pyramid network (PAFPN) and balanced feature pyramid (BFP) were integrated into the SSD network. Experimental results demonstrate that the mean average precision at the IoU (intersection over union) threshold of 0.5 (mAP@0.5) of JujubeSSD reached 97.1%, representing an improvement of approximately 6.35% compared to the original algorithm. When compared to existing algorithms, such as YOLOv5 and Faster R-CNN, the improvements in mAP@0.5 were 16.84% and 8.61%, respectively. Therefore, the proposed method for detecting jujube disease spot achieves superior performance in jujube surface disease detection and meets the requirements for practical application in agricultural production.

3D-printed bioink loading with stem cells and cellular vesicles for periodontitis-derived bone defect repair.

The suitable microenvironment of bone regeneration is critically important for periodontitis-derived bone defect repair. Three major challenges in achieving a robust osteogenic reaction are the exist of oral inflammation, pathogenic bacteria invasion and unaffluent seed cells. Herein, a customizable and multifunctional 3D-printing module was designed with glycidyl methacrylate (GMA) modified epsilon-poly-L-lysine (EPLGMA) loading periodontal ligament stem cells (PDLSCs) and myeloid-derived suppressive cells membrane vesicles (MDSCs-MV) bioink (EPLGMA/PDLSCs/MDSCs-MVs, abbreviated as EPM) for periodontitis-derived bone defect repair. The EPM showed excellent mechanical properties and physicochemical characteristics, providing a suitable microenvironment for bone regeneration.In vitro, EPMs presented effectively kill the periodontopathic bacteria depend on the natural antibacterial properties of the EPL. Meanwhile, MDSCs-MV was confirmed to inhibit T cells through CD73/CD39/adenosine signal pathway, exerting an anti-inflammatory role. Additionally, seed cells of PDLSCs provide an adequate supply for osteoblasts. Moreover, MDSCs-MV could significantly enhance the mineralizing capacity of PDLSCs-derived osteoblast. In the periodontal bone defect rat model, the results of micro-CT and histological staining demonstrated that the EPM scaffold similarly had an excellent anti-inflammatory and bone regeneration efficacyin vivo. This biomimetic and multifunctional 3D-printing bioink opens new avenues for periodontitis-derived bone defect repair and future clinical application.

Co-exposure levels of volatile organic compounds and metals/metalloids in children: Implications for E-waste recycling activity prediction.

Identifying informal e-waste recycling activity is crucial for preventing health hazards caused by e-waste pollution. This study attempted to build a prediction model for e-waste recycling activity based on the differential exposure biomarkers of the populations between the e-waste recycling area (ER) and non-ER. This study recruited children in ER and non-ER and conducted a quasi-experiment among the adult investigators to screen differential exposure or effect biomarkers by measuring urinary 25 volatile organic compound (VOC) metabolites, 18 metals/metalloids, and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Compared with children of the non-ER, the ER children had higher metal/metalloid (e.g., manganese [Mn], lead [Pb], antimony [Sb], tin [Sn], and copper [Cu]) and VOC exposure (e.g., carbon-disulfide, acrolein, and 1-bromopropane) levels, oxidative DNA damage, and non-carcinogenic risks. Individually added 8-OHdG, VOC metabolites, and metals/metalloids to the support vector machine (SVM) classifier could obtain similar classification effects, with the area under curve (AUC) ranging from 0.741 to 0.819. The combined inclusion of 8-OHdG and differential VOC metabolites, metals/metalloids, and mixed indexes (e.g., product items or ratios of different metals/metalloids) in the SVM classifier showed the highest performance in predicting e-waste recycling activity, with an AUC of 0.914 and prediction accuracy of 83.3 %. "Sb × Mn", followed by "Sn × Pb/Cu", "Sb × Mn/Cu", and "Sn × Pb", were the top four important features in the models. Compared with non-ER children, the levels of urinary Mn, Pb, Sb, Sn, and Cu in ER children were 1.2 to 2.4 times higher, while the levels of "Sb × Mn", "Sn × Pb/Cu", "Sb × Mn/Cu", and "Sn × Pb" were 3.5 to 4.7 times higher, suggesting that these mixed indexes could amplify the differences between e-waste exposed and non-e-waste exposed populations. With the continued inclusion of new biomarkers of e-waste pollution in the future, our prediction model is promising for screening informal e-waste recycling sites.

Volatile organic compounds and metals/metalloids exposure in children after e-waste control: Implications for priority control pollutants and exposure mitigation measures.

The decade-long effort to control e-waste in China has made significant progress from haphazard disposal to organized recycling, but environmental research suggests that exposure to volatile organic compounds (VOCs) and metals/metalloids (MeTs) still poses plausible health risks. To investigate the exposure risk faced by children and identify corresponding priority control chemicals, we evaluated the carcinogenic risk (CR), non-CR, and oxidative DNA damage risks of VOCs and MeTs exposure in 673 children from an e-waste recycling area (ER) by measuring urinary exposure biomarker levels. The ER children were generally exposed to high levels of VOCs and MeTs. We observed distinctive VOCs exposure profiles in ER children. In particular, the 1,2-dichloroethane/ethylbenzene ratio and 1,2-dichloroethane were promising diagnostic indexes for identifying e-waste pollution due to their high accuracy (91.4%) in predicting e-waste exposure. Exposure to acrolein, benzene, 1,3-butadiene, 1,2-dichloroethane, acrylamide, acrylonitrile, arsenic, vanadium, copper, and lead posed considerable CR or/and non-CR and oxidative DNA damage risks to children, while changing personal lifestyles, especially enhancing daily physical exercise, may facilitate mitigating these chemical exposure risks. These findings highlight that the exposure risk of some VOCs and MeTs is still non-negligible in regulated ER, and these hazardous chemicals should be controlled as priorities.

Associations between trace level thallium and multiple health effects in rural areas: Chinese Exposure and Response Mapping Program (CERMP).

Thallium (Tl) is a cumulative high toxicant in the environment, but few studies have investigated the comprehensive health effects underlying chronic Tl exposure at trace levels. This study aims to evaluate the liver, kidney, lung and other potential health effects associated with chronic Tl exposure at trace levels in rural areas of China. Urinary Tl concentrations of 2883 adults from rural areas of 12 provinces in China were measured and 2363 participants were involved in the final analysis. Indicators of liver and kidney functions in the serum, as well as the lung function indicators, were determined in the participants. General linear regression and restricted cubic spline regression were combined to study the associations between urinary Tl and health indicators or outcomes. In this study, the detected rate of Tl in the urine of the participants was 97.28 %. When the urinary Tl concentration was ranged at the fourth quintile, the risk of having liver function disorder was 70 % higher [Odds ratio (OR) = 1.70 (95 % confidence intervals (CI): 1.30, 2.22)] in all the participants, whereas the farmers were more likely to have the disorder [OR = 2.08 (95 % CI: 1.49, 2.92)] than the non-farmers [OR = 1.20 (95 % CI: 0.77, 1.88)]. Nonlinear associations between most of the liver health indicators and urinary Tl were identified, of which serum bilirubin was strongly associated with the elevation of urinary Tl when its concentration was >0.40 µg/g creatinine. Besides, urinary Tl was negatively associated with lung health indicators. Our study proposes the safety re-assessment of the current exposure level of Tl in the environment, especially in rural areas of China.

Molybdenum Chloride Nanostructures with Giant Lattice Distortions Intercalated into Bilayer Graphene.

The nanospace of the van der Waals (vdW) gap between structural units of two-dimensional (2D) materials serves as a platform for growing unusual 2D systems through intercalation and studying their properties. Various kinds of metal chlorides have previously been intercalated for tuning the properties of host layered materials, but the atomic structure of the intercalants remains still unidentified. In this study, we investigate the atomic structural transformation of molybdenum(V) chloride (MoCl5) after intercalation into bilayer graphene (BLG). Using scanning transmission electron microscopy, we found that the intercalated material represents MoCl3 networks, MoCl2 chains, and Mo5Cl10 rings. Giant lattice distortions and frequent structural transitions occur in the 2D MoClx that have never been observed in metal chloride systems. The trend of symmetric to nonsymmetric structural transformations can cause additional charge transfer from BLG to the intercalated MoClx, as suggested by our density functional theory calculations. Our study deepens the understanding of the behavior of matter in the confined space of the vdW gap in BLG and provides hints at a more efficient tuning of material properties by intercalation for potential applications, including transparent conductive films, optoelectronics, and energy storage.

Association between long-term green space exposure and mortality in China: A difference-in-differences analysis of national data in 2000, 2010 and 2019.

BACKGROUND: Effects of green space on human health have been well-documented in western, high-income countries. Evidence for similar effects in China is limited. Moreover, the underlying mechanisms linking green space and mortality are yet to be established. We therefore conducted a nation-wide study to assess the association between green space and mortality in China using a difference-in-difference approach, which applied a causal framework and well controlled unmeasured confounding. In addition, we explored whether air pollution and air temperature could mediate the association. METHODS: In this analysis, we collected data on all-cause mortality and sociodemographic characteristics for each county in China from the 2000 and 2010 censuses and the 2020 Statistical Yearbook. Green space exposure was assessed using county-level normalized difference vegetation index (NDVI) and the percentage of green space (forest, grasslands, shrub land and wetland). We applied a difference-in-differences approach to evaluate the association between green space and mortality. We also performed mediation analysis (by air pollution and air temperature). RESULTS: Our sample consisted of 2726 counties in 2000 and 2010 as well as 1432 counties in 2019. In the 2000 versus 2019 comparison, a 0.1 unit increase in NDVI was associated with a 2.4 % reduction in mortality [95 % confidence interval (CI) 0.4-4.3 %], and a 10 % increase in percentage of green space was associated with a 4.7 % reduction (95 % CI 0-9.2 %) in mortality. PM2.5 and air temperature mediated 0.3 % to 12.3 % of the associations. CONCLUSIONS: Living in greener counties may be associated with lower risk of mortality in China. These findings could indicate the potential of a population-level intervention to reduce mortality in China, which has important public health implications at the county level.

[Heavy Metal Pollution Characteristics and Risk Assessment of Golden Snub-nosed Monkey (Rhinopithecus roxellana) Habitat in Shennongjia Mountains].

The golden snub-nosed monkey is one of the most endangered animal species endemic to China. In order to explore the characteristics and health risks of golden snub-nosed monkeys exposed to heavy metals, we collected the plant food sources, soil, and water samples from the golden snub-nosed monkey habitat in the Shennongjia Mountains; examined the contents of seven heavy metals (Cu, Zn, Pb, Cd, Cr, Ni, and As); and adopted the comprehensive pollution index, potential ecological risk index, and Nemerow index to evaluate pollutants in the water, soil, and food plants. At the same time, the Target Hazard Quotient method was used to assess heavy metals in the food plants. The results showed that the heavy metal concentration of the habitat water was 0.004-1.220 µg·L-1. The water comprehensive pollution index showed that the habitat water was safe. In addition, the ω(Cd)(0.162-0.822 mg·kg-1) in the soil was 2.71 times the background value of the soil in Hubei province, indicating a moderate risk of ecological harm. The over-standard rates of Pb, Cd, Cr, and Ni in food plants were 29%, 29%, 18%, and 35%, respectively; the pollution indexes of lichen and bark were 6.038 and 7.709, which were at a heavy pollution level; and the pollution indexes of Abies fragesii and Vicia cracca were 2.716 and 2.034, which indicated a moderately polluted level. The rest of the plants were at a safe level. Our health risk analysis showed that the risk of lichen and bark were higher than that of leaves, followed by fruits. Among the seven metals, As most threatened the health of the golden snub-nosed monkeys (THQ>1). In general, heavy metals had polluted the habitats of the golden snub-nosed monkeys in the Shennongjia Mountains, and we are certain that the heavy metal pollution was associated with human activities. Thus, human activities in the Shennongjia Mountains should be reasonably restricted in the future. Our results can provide scientific support for the population conservation of golden snub-nosed monkeys in China and provide research samples in the health risk valuation of heavy metals in endangered animals through food plants.

[Inhibitory Effects of Soil Amendment Coupled with Water Management on the Accumulation of Cd and Pb in Double-Cropping Rice].

The bioavailability of heavy metals in soil and the physiological activities of rice determine the accumulation of heavy metals in brown rice. In this study, a field experiment was conducted in a rice paddy in which the total amount of Cd in the soil did not exceed the national standard, whereas the Cd in rice grains was at risk of overreaching in the suburbs of Guangzhou city. The bioavailability of heavy metals in the soil and the physiological barrier of rice were taken as the starting point. The early and late rice yield, brown rice heavy metal content, Cd and Pb enrichment coefficient, total soil heavy metals, soil physical and chemical properties, and soil Cd and Pb species distribution were investigated under the Si-rich amendment (JD), Ca-Mg amendment (YY), Si-rich amendment+flooding irrigation (JD+YS), and Ca-Mg amendment+flooding irrigation (YY+YS) treatments. The results showed that:① the total ω(Cd) in the soil was only 0.13 mg·kg-1 in the CK treatment. However, the average ω(Cd) in the grain of early rice reached up to 0.19 mg·kg-1. The early rice varieties (hybrid rice) had a more vital ability to accumulate Cd and total As in brown rice than that in late rice varieties (conventional rice) but a lower capacity for Pb accumulation. ② JD and YY application alone had no noticeable inhibitory effect on the accumulation of Cd and Pb in brown rice; however, JD+YS and YY+YS treatments significantly inhibited the accumulation of Cd and Pb in brown rice in both early and late rice, especially in the JD+YS treatment, which decreased the Cd and Pb accumulation by 65.8% and 68% for early rice and by 71.43% and 49.15% for late rice, respectively. The primary mechanism of JD+YS was to increase soil pH and maintain a low redox potential to promote soil Cd and Pb to be transformed from acid-soluble to a reduced state and residue state, thus decreasing Cd and Pb to migrate from the soil to the rice. At the same time, it effectively suppressed the absorption and transportation of Cd and Pb by early and late rice via the physiological barrier effect of Si nutrition and the competition for transportation channels between calcium and magnesium ions and cadmium and inhibited the accumulation of Cd and Pb in the brown rice of early and late rice. These results provide a theoretical basis for the exploration and application of the control technologies in the brown rice Cd and Pb resistance and have important practical significance for guiding the safe production in the rice-growing area in South China.

Significance of biotransformation and excretion on the enantioselective bioaccumulation of hexabromocyclododecane (HBCDD) in laying hens and developing chicken embryos.

Although (-)-α-hexabromocyclododecane (HBCDD) and (+)-γ-HBCDD are preferentially enriched in chickens, the key factors contributing to their selective bioaccumulation in hens and their potential biotransformation in developing chicken embryos remain unclear. Herein, in vivo and in ovo exposure experiments using hens and fertilized eggs were conducted to investigate the absorption, excretion, and biotransformation of HBCDDs in chickens. γ-HBCDD (76%) exhibited a higher absorption efficiency than α- (22%) and ß- (69%) HBCDDs. However, α-HBCDD was dominant in hen tissues, although γ-HBCDD accounted for >75% in the spiked feed. Moreover, chicken embryos biotransformed approximately 9.5% and 11.7% of absorbed α- and γ-HBCDDs, respectively, implying that diastereomer-selective elimination causes the predominance of α-HBCDD in hens. The concentration and enantiomer fraction (EF) of α-HBCDD in laid eggs were significantly positively correlated, suggesting enantioselective elimination. The EFs of α- and γ-HBCDDs varied between feces from the exposure and depuration periods, indicating the preferred excretion of (+)-α- and (-)-γ-HBCDDs. Furthermore, the enantioselective biotransformation of (-)-γ-HBCDD was confirmed in developing chicken embryos. These results show that excretion and biotransformation contribute to the diastereomer- and enantiomer-selective bioaccumulation of HBCDDs in chickens; The results may improve our understanding of the environmental fate and ecological risks of HBCDDs in biota.

Composition-dependent photoconductivities in indium aluminium nitride nanorods grown by magnetron sputter epitaxy.

Photoconduction (PC) properties were investigated for ternary indium aluminium nitride (In x Al1-x N) nanorods (NRs) with different indium compositions (x) from 0.35 to 0.68, as grown by direct-current reactive magnetron sputter epitaxy. Cross-sectional scanning transmission electron microscopy (STEM) reveals single-crystal quality of the vertically aligned In x Al1-x N NRs. Single-rod photodetector devices with good ohmic contacts were fabricated using the focused-ion-beam technique (FIB), where the In-rich In0.68Al0.32N NR exhibits an optimal photocurrent responsivity of 1400 A W-1 and photoconductive gain of 3300. A transition from a positive photoresponse to a negative photoresponse was observed, while increasing the In composition x from 0.35 to 0.57. The negative PC was further enhanced by increasing x to 0.68. A model based on the coexistence and competition of deep electron trap states and recombination centers was proposed to explain the interesting composition-dependent PC in these ternary III-nitride 1D nanostructures.

WSe2/WS2 Heterobilayer Nonvolatile Memory Device with Boosted Charge Retention.

A two-dimensional (2D) nonvolatile memory device architecture to improve the long-term charge retention with the minimum charge loss without compromising storage capacity and the extinction ratio for practical applications has been an imminent demand. To address the current issue, we adopted a novel type-II band-aligned heterobilayer channel comprising vertically stacked monolayer WSe2 nanodots on monolayer WS2. The band offset modulation leads to electron doping from WSe2 nanodots into the WS2 channel without any external driving electric field. As a result, the tested device outperformed with a memory window as high as 34 V and a negligible charge loss of 7% in a retention period of 10 years while maintaining a high extinction ratio of 106. The doping technique presented in this work provides a feasible route to modulate the electrical properties of 2D channel materials without hampering charge transport, paving the way for high-performance 2D memory devices.