Selective and efficient immobilization of cadmium in soil by layered double hydroxides intercalated with the mercaptosuccinic acid.

Cadmium (Cd) contamination in cropland poses a significant threat to the quality of agricultural products, but even though in-situ remediation has been extensively applied, non-selective immobilization remains an issue. In order to develop a material that specifically immobilizes Cd in soil, a layered double hydroxide, intercalated with mercaptosuccinic acid (MSA-CFA), was synthesized through co-precipitation. In this case, the MSA-CFA's maximum adsorption capacity was increased from the 513.8 mg·g-1 for unintercalated hydrotalcite CFA to 692.6 mg·g-1. Besides, MSA-CFA efficiently removed 99.25 % of Cd from soil water-extract solution and immobilized up to 70.03 % of bio-available Cd. However, interestingly, its immobilization effects on beneficial metal elements Fe, Mn and Zn were milder, being equivalent to 2/7, 5/7 and 1/2 that of lime, respectively. Moreover, XRD and XPS techniques revealed isomorphous substitution with calcium and sulfhydryl complexation during the Cd adsorption by MSA-CFA. Compared with CFA, the increased adsorption capacity of MSA-CFA for Cd was due to intercalated MSA acting as a new adsorption site, while the enhanced selectivity was contributed by sulfhydryl's affinity for Cd. Altogether, MSA-CFA showed great promise as a competitive and highly efficient candidate amendment in Cd-contaminated soil remediation.

Application of Computed Tomography Angiography in Preoperative Diagnosis of Coarctation of Aorta and Evaluation of Aortic Dilatation in Infants.

OBJECTIVE: To evaluate the occurrence of aortic dilatation and its associated predictors with coarctation of the aorta (CoA) in infants using multi-slice computed tomography (MSCT). METHODS: The clinical data of 47 infantile patients with CoA diagnosed by MSCT and 28 infantile patients with simple ventricular septal defect were analyzed retrospectively. Aortic diameters were measured at six different levels, and aortic sizes were compared by z score. The coarctation site-diaphragm ratio was used to describe the degree of narrowing. Relevant clinical data were collated and analyzed. RESULTS: The dilation rate and z score of the ascending aorta in the severe CoA group were significantly higher than those in the mild CoA group (11 [52.38%] vs. 21 [80.77%], P=0.038 and 2.00 ± 0.48 vs. 2.36 ± 0.43, P=0.010). Pearson's correlation analysis found that the z score of the ascending aorta was negatively correlated with the coarctation site-diaphragm ratio value (r=-0.410, P=0.004). A logistic retrospective analysis found that an increased degree of coarctation was an independent predictor of aortic dilatation (adjusted odds ratio 0.002; 95% confidence interval 0.00-0.819; P=0.043). The z score of the ascending aorta in the severe CoA group was significantly higher than that in the ventricular septal defect group (P<0.05). CONCLUSION: Most infants with CoA can also have significant dilatation of the ascending aorta, and the degree of this dilatation is related to the degree of coarctation. Assessment of aortic diameter and related malformations by MSCT can predict the risk of aortic dilatation in infants with CoA.

Electronic structure of superconducting VN(111) films.

Vanadium nitride (VN) is a transition-metal nitride with remarkable properties that have prompted extensive experimental and theoretical investigations in recent years. However, there is a current paucity of experimental research investigating the temperature-dependent electronic structure of single-crystalline VN. In this study, high-quality VN(111) films were successfully synthesized on α -Al 2 O 3 (0001) substrates using magnetron sputtering. The crystal and electronic structures of the VN films were characterized by a combination of high-resolution X-ray diffraction, low-energy electron diffraction, resonant soft X-ray absorption spectroscopy, and ultraviolet photoelectron spectroscopy. The electrical transport measurements indicate that the superconducting critical temperature of the VN films is around 8.1 K. Intriguingly, the temperature-dependent photoelectron spectroscopy measurements demonstrate a weak temperature dependence in the electronic structure of the VN films, which is significant for understanding the ground state of VN compounds.

Application of Computed Tomography Angiography in Preoperative Diagnosis of Coarctation of Aorta and Evaluation of Aortic Dilatation in Infants

ABSTRACT Objective: To evaluate the occurrence of aortic dilatation and its associated predictors with coarctation of the aorta (CoA) in infants using multi-slice computed tomography (MSCT). Methods: The clinical data of 47 infantile patients with CoA diagnosed by MSCT and 28 infantile patients with simple ventricular septal defect were analyzed retrospectively. Aortic diameters were measured at six different levels, and aortic sizes were compared by z score. The coarctation site-diaphragm ratio was used to describe the degree of narrowing. Relevant clinical data were collated and analyzed. Results: The dilation rate and z score of the ascending aorta in the severe CoA group were significantly higher than those in the mild CoA group (11 [52.38%] vs. 21 [80.77%], P=0.038 and 2.00 ± 0.48 vs. 2.36 ± 0.43, P=0.010). Pearson's correlation analysis found that the z score of the ascending aorta was negatively correlated with the coarctation site-diaphragm ratio value (r=-0.410, P=0.004). A logistic retrospective analysis found that an increased degree of coarctation was an independent predictor of aortic dilatation (adjusted odds ratio 0.002; 95% confidence interval 0.00-0.819; P=0.043). The z score of the ascending aorta in the severe CoA group was significantly higher than that in the ventricular septal defect group (P<0.05). Conclusion: Most infants with CoA can also have significant dilatation of the ascending aorta, and the degree of this dilatation is related to the degree of coarctation. Assessment of aortic diameter and related malformations by MSCT can predict the risk of aortic dilatation in infants with CoA.

The Effect of Key Electronic States on Excess Lithium Intercalation in Li2RuyMn1-yO3.

Excess reversible lithium storage is an alternative crucial strategy besides the expansion of redox centers to boost the capacity of layered cathodes. However, the mechanism of excess Li+ intercalation is far from being comprehended, indisputably hindering the development of layered cathodes. Herein, the comparative study of Li2RuyMn1-yO3 and Li2RuyTi1-yO3 by X-ray absorption and photoemission spectroscopies attempts to illustrate the origin. The charge transfer from Ru to Mn through TM-O π bonding interaction with the formation of O holes has been revealed in Li2RuyMn1-yO3, which originates from the inductive effect and the approaching energy level of Mn and Ru bands. The electronic state is thought to reduce the Coulomb repulsion of Li+ with the matrix, promoting excess Li+ intercalation. The results are instructive to the rational design of layered cathodes to achieve a larger reversible capacity in a wide voltage window.

Synthesis, Characterization of Low Molecular Weight Chitosan Selenium Nanoparticles and Its Effect on DSS-Induced Ulcerative Colitis in Mice.

Selenium nanoparticles have attracted extensive attention due to their good bioavailability and activity. In the present study, a new form of selenium nanoparticle (Low molecular weight chitosan selenium nanoparticles (LCS-SeNPs)) were synthesized in a system of sodium selenite and acetic acid. The size, element state, morphology and elementary composition of LCS-SeNPs were characterized by using various spectroscopic and microscopic measurements. The protection of LCS-SeNPs against dextran sulfate sodium (DSS)-induced intestinal barrier dysfunction and the inherent mechanisms of this process were investigated. The results showed that LCS-SeNPs, with an average diameter of 198 nm, zero-valent and orange-red relatively uniform spherical particles were prepared. LCS-SeNPs were mainly composed of C, N, O and Se elements, of which Se accounted for 39.03% of the four elements C, N, O and Se. LCS-SeNPs reduced colon injury and inflammation symptoms and improved intestinal barrier dysfunction. LCS-SeNPs significantly reduced serum and colonic inflammatory cytokines TNF-α and IL-6 levels. Moreover, LCS-SeNPs remarkably increased antioxidant enzyme GSH-Px levels in serum and colonic tissue. Further studies on inflammatory pathways showed that LCS-SeNPs alleviated DSS-induced colitis through the NF-κB signaling pathway, and relieved inflammatory associated oxidative stress through the Nrf2 signaling pathway. Our findings suggested that LCS-SeNPs are a promising selenium species with potential applications in the treatment of oxidative stress related inflammatory intestinal diseases.

Overall and thermal comfort under different temperature, noise, and vibration exposures.

Public transports like the bus and subway inherently experience noise, vibration, and temperature variations that are different from building environment. Each of them can influence passengers' comfort, but little is known about their combined effects, especially how they affect thermal comfort. This paper presents experimental results from a series of human subject tests under different noises, vibrations, and temperatures. 32 subjects' subjective perception and physiological response were collected under three temperatures (22.5, 25.5, 28.5℃), five noise levels (55, 60, 65, 70, 75 dB(A)), and five vibrating accelerations (0, 0.2, 0.4, 0.6, 0.8 m/s2 ). We also varied the noise and vibration spectrums to simulate the bus and subway environments. In total, 48 195-min and 192 115-min laboratory tests were conducted. By using significance tests (paired t tests and two-way ANOVA tests) and sensitivity analysis (Treed Gaussian Process), the results show that temperature, noise, and vibration exposures can significantly affect subjects' overall satisfaction. More interestingly, high noise and vibration levels can cause warmer thermal sensations. A change in the noise of 20 dB(A) or vibration of 0.6 m/s2 is equivalent to an ambient temperature change of 0.6 °C. We also observed higher heart rates and metabolic heat production at higher levels of noise and vibrating accelerators. Based on the test results, regression models were developed to describe the combined effects of temperature, noise, and vibration on subjects' overall comfort perception and thermal neutral temperature. They can serve as references for the design and operation of public transport environments.

Productivity improvement and charge variant modulation for intensified cell culture processes by adding a carboxypeptidase B (CpB) treatment step.

The goal of cell culture process intensification is to improve productivity while maintaining acceptable quality attributes. In this report, four processes, namely a conventional manufacturing Process A, and processes intensified by enriched N-1 seed (Process B), by perfusion N-1 seed (Process C), and by perfusion production (Process D) were developed for the production of a monoclonal antibody. The three intensified processes substantially improved productivity, however, the product either failed to meet the specification for charge variant species (main peak) for Process D or the production process required early harvest to meet the specification for charge variant species, Day 10 or Day 6 for Processes B and C, respectively. The lower main peak for the intensified processes was due to higher basic species resulting from higher C-terminal lysine. To resolve this product quality issue, we developed an enzyme treatment method by introducing carboxypeptidase B (CpB) to clip the C-terminal lysine, leading to significantly increased main peak and an acceptable and more homogenous product quality for all the intensified processes. Additionally, Processes B and C with CpB treatment extended bioreactor durations to Day 14 increasing titer by 38% and 108%, respectively. This simple yet effective enzyme treatment strategy could be applicable to other processes that have similar product quality issues.

[Combined Effect of Weathered Coal Based Amendments and Soil Water Management on Methylmercury Accumulation in Paddy Soil and Rice Grains].

A pot experiment and field experiment were designed to study the changes in the grain methyl mercury content in paddy soil and rice yield by sowing soil amendments that contained weathered coal, CaCO3, and Na2SeO3 as the main raw materials, combined with water management in a paddy field (80% field capacity after the heading and flowering periods). The results showed that:① In pot experiment, the content of methylmercury in rice rhizosphere soil decreased by 86.6% and the content of methylmercury in the rice grains decreased by 65.2% compared with that of the control. In field experiment, the content of methylmercury in rice rhizosphere soil decreased by 77.4% and the content of methylmercury in rice grains decreased by 60.6% upon adding the amendment+water management compared with that of CK. ② The soil pH increased by more than 0.3 in the pot experiment and 0.2 in the field experiment compared with that of the control. Furthermore, rice yield and plant biomass did not decrease in the two parts of the experiment. It can be inferred that the soil amendment and agronomic regulation measures (water management) used in this study have the advantages of quick effects, convenient use, and remarkable control effects and without secondary pollution. More, they can effectively reduce the risk of rice methylmercury exposure.

Polysaccharides from Hemp Seed Protect against Cyclophosphamide-Induced Intestinal Oxidative Damage via Nrf2-Keap1 Signaling Pathway in Mice.

Hemp seed has been used as a traditional oriental medicine and health food in China for centuries. Polysaccharides from hemp seed (HSP) exhibit important properties of intestinal protection, but there are limited data on the specific underlying mechanism. The primary objective of this study was to investigate the protective effect of HSP on intestinal oxidative damage induced by cyclophosphamide (Cy) in mice. The results showed that pretreatment with HSP significantly increased the average daily gain, thymus index, spleen index, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activity in serum and ileal homogenate and significantly reduced malondialdehyde (MDA) content in ileal homogenate. In addition, the expression levels of SOD, GSH-Px, Nrf2, heme oxidase-1 (HO-1), and quinoneoxidoreductase-1 (NQO1) mRNA in ileal homogenate were significantly increased. Western blot results showed that HSP significantly upregulated the expression of Nrf2 protein and downregulated the expression of Keap1 protein in the ileum. Collectively, our findings indicated that HSP had protective effects on intestinal oxidative damage induced by Cy in mice, and its mechanism might be related to the activation of Nrf2-Keap1 signaling pathway.

Clinicopathological characteristics and surgical outcomes of sarcomatoid hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is the sixth most common type of cancer and the fourth leading cause of cancer-related death worldwide. Sarcomatoid HCC, which contains poorly differentiated carcinomatous and sarcomatous components, is a rare histological subtype of HCC that differs from conventional HCC. It is highly aggressive and has a poor prognosis. Its clinicopathological characteristics, surgical outcomes and underlying mechanisms of its highly aggressive nature have not been fully elucidated. AIM: To examine the clinicopathological characteristics and surgical outcomes of sarcomatoid HCC and explore the histogenesis of sarcomatoid HCC. METHODS: In total, 196 patients [41 sarcomatoid HCC and 155 high-grade (Edmondson-Steiner grade III or IV) HCC] who underwent surgical resection between 2007 and 2017 were retrospectively reviewed. The characteristics and surgical outcomes of sarcomatoid HCC were compared with those of patients with high-grade HCC. The histological composition of invasive and metastatic sarcomatoid HCCs was evaluated. RESULTS: Sarcomatoid HCC was more frequently diagnosed at an advanced stage with a larger tumor and higher rates of nonspecific symptom, adjacent organ invasion and lymph node metastasis than high-grade HCC (all P < 0.05). Compared with high-grade HCC patients, sarcomatoid HCC patients are less likely to have typical dynamic imaging features of HCC (44.4% vs 72.7%, P = 0.001) and elevated serum alpha-fetoprotein levels (> 20 ng/mL; 36.6% vs 78.7%, P < 0.001). The sarcomatoid group had a significantly shorter median recurrence-free survival (5.6 mo vs 16.4 mo, log-rank P < 0.0001) and overall survival (10.5 mo vs 48.1 mo, log-rank P < 0.0001) than the high-grade group. After controlling for confounding factors, the sarcomatoid subtype was identified as an independent predictor of poor prognosis. Pathological analyses indicated that invasive and metastatic lesions were mainly composed of carcinomatous components. CONCLUSION: Sarcomatoid HCC was associated with a more advanced stage, atypical dynamic imaging, lower serum alpha-fetoprotein levels and a worse prognosis. The highly aggressive nature of sarcomatoid HCC is perhaps mediated by carcinomatous components.

Upregulation of Holliday junction recognition protein predicts poor prognosis and biochemical recurrence in patients with prostate cancer.

Abnormal expression of Holliday junction recognition protein (HJURP) in several types of tumor cells plays a vital role in the formation and progression of tumors. Few studies have investigated the role of HJURP in prostate cancer (PCa). The aim of this study was to analyze the expression levels of HJURP in PCa and to establish the association with clinicopathological data. Reverse transcription quantitative polymerase chain reaction and immunohistochemical analysis were used to detect the expression levels of HJURP in benign and PCa prostate tissues. The Taylor dataset was statistically analyzed to determine if HJURP expression levels were associated with PCa clinicopathological data. HJURP was overexpressed in PCa tissues compared with benign prostate tissues. Statistical analysis of the Taylor dataset indicated that upregulation of HJURP was significantly associated with positive prostate-specific antigen (PSA) levels (P=0.004), high Gleason score (P=0.005), advanced pathological stage (P=0.007), metastasis (P<0.001) and PSA failure (P<0.001). Higher HJURP mRNA expression levels were significantly associated with shorter biochemical recurrence (BCR)-free survival (P<0.001). To the best of our knowledge, this study is the first report of HJURP upregulation in PCa tissues. Upregulation of HJURP may predict BCR-free survival and HJURP may be an oncogene that impacts the prognosis of patients with PCa.

Low Molecular Seleno-Aminopolysaccharides Protect the Intestinal Mucosal Barrier of Rats under Weaning Stress.

Low molecular seleno-aminopolysaccharide (LSA) was synthesized with sodium selenite and low molecular aminopolysaccharide (LA), which is an organic selenium compound. This study is aimed to investigate the protective effect of LSA on the intestinal mucosal barrier in weaning stress rats by detecting the intestinal tissue morphology and function, mucosal thickness and permeability, the structure of MUC2, antioxidant index, the expression level of intracellular transcription factor NF-E2-related factor 2 (Nrf2), and its related factors. The results showed that LSA significantly increased the height of intestinal villi (p < 0.05) and increased the thickness of intestinal mucosa and the number of goblet cells, which indicated that LSA has a protective effect on the intestinal mucosal barrier that is damaged by weaning. Moreover, LSA significantly reduced the level of DAO, D-LA, and LPS compared with the weaning group (p < 0.05), which indicated that LSA reduced the intestinal damage and permeability of weaning rats. In addition, LSA could increase the number and length of glycans chains and the abundance of acid glycans structures in the MUC2 structure, which indicated that LSA alleviated the changes of intestinal mucus protein structure. LSA significantly increased the levels of GSH-Px, SOD, LDH, and CAT, while it decreased the level of MDA in serum and intestinal tissue, which suggested that LSA significantly enhanced the antioxidant capacity and reduced oxidative stress of weaning rats. RT-PCR results showed that LSA significantly increased the expression level of antioxidant genes (GSH-Px, SOD, Nrf2, HO-1), glycosyltransferase genes (GalNT1, GalNT3, GalNT7) and mucin gene (MUC2) in intestinal mucosa (p < 0.05). The results of western blot showed that the LSA activated the Nrf2 signaling pathway by down-regulating the expression of Keap1and up-regulating the expression of Nrf2, and protected the intestinal mucosa from oxidative stress. Overall, LSA could play a protective role in intestinal mucosal barrier of weaning rats by activating the Nrf2 pathway and alleviating the alnormal change of mucin MUC2.

Protective effect of polysaccharides of sea cucumber Acaudina leucoprocta on hydrogen peroxide-induced oxidative injury in RAW264.7 cells.

The aim of this experiment was to investigate the protective effects of polysaccharides of sea cucumber Acaudina leucoprocta (ALP) against hydrogen peroxide (H2O2) induced oxidative injury in RAW264.7 cells. Analysis of monosaccharide composition and structure of one fraction from ALP (ALPN) were analyzed by High Performance Liquid Chromatography (HPLC) and Fourier Transform Infrared Spectoscopy (FT-IR). The results showed that ALPN contain sulfate groups, which is sulfated polysaccharides. The results from MTT assay indicated that ALPN could markedly increase viability of cells compared with RAW264.7 cells exposed to H2O2. Moreover, ALPN significantly increased the levels of catalase (CAT), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD), decreased the production of malondialdehyde (MDA) and lactate dehydrogenase (LDH) in RAW264.7 cells. The data from RT-PCR showed that ALPN (300 µg/mL) could increase the gene expression levels of SOD1 and GPX1. ALPN could also observably increase the protein expression level of Nrf2 and decrease the protein expression level of Keap1 with western blot. Collectively, this study suggested that polysaccharides of sea cucumber Acaudina leucoprocta (ALP) could effectively protect RAW264.7 cells against H2O2-induced oxidative injury. This protection mechanism may be related to activation of the Nrf2/Keap1 signaling pathway.

MiR-34a overexpression enhances the inhibitory effect of doxorubicin on HepG2 cells.

BACKGROUND: Hepatocellular carcinoma (HCC) is the third leading cause of death from malignant tumors worldwide. More than 50% of HCC cases occur in China. The prognosis remains poor and overall efficacy is still unsatisfactory. Chemotherapy resistance is the most important reason for the poor outcome. Much progress has been made in the study of chemotherapy resistance of HCC; however, the specific mechanisms of progression of HCC have still only been partially established. Therefore, the mechanism of chemotherapy resistance in HCC requires more research. AIM: To investigate the effect of miR-34a expression on the growth inhibition of HepG2 cells by doxorubicin. METHODS: A recombinant lentiviral vector containing miR-34a was constructed and transfected into HepG2 cells. The expression of miR-34a was detected by reverse transcription-polymerase chain reaction (commonly known as RT-PCR) before and after transfection. Cells were exposed to 2 µM doxorubicin or phosphate-buffered saline before and after transfection. Cell viability in each group was detected by MTT assay, and cell cycle and apoptosis were detected by flow cytometry. Changes in expression levels of phospho (p)-p53, sirtuin (SIRT) 1, cyclin D1, cyclin-dependent kinase (CDK) 4, CDK6, BCL-2, multidrug resistance protein (MDR) 1/P glycoprotein (P-gp), and AXL were detected by Western blotting. RESULTS: Recombinant lentiviral vector LV-hsa-mir-34a was successfully constructed by restriction endonuclease digestion and sequencing. RT-PCR showed that expression of miR-34a in HepG2 cells was significantly upregulated after transfection (P < 0.01). MTT assay showed that growth of HepG2 cells was inhibited after upregulation of miR-34a, and viability was significantly decreased after combined treatment with doxorubicin (P < 0.01). Flow cytometry showed that the number of HepG2 cells in G1 phase increased, and G1 phase arrest was more obvious after intervention with doxorubicin (P < 0.01). The apoptosis rate of HepG2 cells was increased after upregulation of miR-34a, and became more obvious after intervention with doxorubicin (P < 0.01). Western blotting showed that upregulation of miR-34a combined with treatment with doxorubicin caused significant changes in the expression levels of p-p53, SIRT1, cyclin D1, CDK4, CDK6, BCL-2, MDR1/P-gp and AXL proteins (P < 0.01). CONCLUSION: MiR-34a may enhance the inhibitory effect of doxorubicin by downregulating MDR1/P-gp and AXL, which may be related to p53 expression.

Hemp seed polysaccharides protect intestinal epithelial cells from hydrogen peroxide-induced oxidative stress.

The purpose of this study was to investigate structure of Hemp seed polysaccharide (HSP) and the protective effect of HSP from H2O2-induced oxidative damage in IPEC-1 cells and the possible mechanism of this protection. Analysis of monosaccharide composition and structure of two fractions HSP0 and HSP0.2 from polysaccharide of Hemp seed (HSPc) were analyzed by high performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FT-IR). The results showed that both HSP0 and HSP0.2 contain sulfate groups, which are sulfated polysaccharides. In IPEC-1 cells model, the release of LDH and MDA was significantly decreased, and the activities of SOD, GSH-Px and CAT were significantly increased in HSP0 and HSP0.2-treated group. HSP0.2 dramatically increased the gene expression of antioxidant enzymes and phase II detoxification enzymes measured by real-time fluorescent quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In addition, HSP0.2 up-regulated the expression level of intracellular transcription factor Nuclear factor erythroid-2-related factor 2 (Nrf2) and inhibited the level of Kelch-like ECH-associated protein 1 (Keap1) with Western blot analysis. Collectively, the present study suggested that HSP0.2 has the protective effect of IPEC-1 cells against H2O2-induecd oxidative stress. This protection mechanism may be related to activation of the Keap1/Nrf2 signaling pathway.

Direct Spectroscopy for Probing the Critical Role of Partial Covalency in Oxygen Reduction Reaction for Cobalt-Manganese Spinel Oxides.

Nanocrystalline multivalent metal spinels are considered as attractive non-precious oxygen electrocatalysts. Identifying their active sites and understanding their reaction mechanisms are essential to explore novel transition metal (TM) oxides catalysts and further promote their catalytic efficiency. Here we report a systematic investigation, by means of soft X-ray absorption spectroscopy (sXAS), on cubic and tetragonal CoxMn3-xO4 (x = 1, 1.5, 2) spinel oxides as a family of highly active catalysts for the oxygen reduction reaction (ORR). We demonstrate that the ORR activity for oxide catalysts primarily correlates to the partial covalency of between O 2p orbital with Mn4+ 3d t2g-down/eg-up, Mn3+ 3d eg-up and Co3+ 3d eg-up orbitals in octahedron, which is directly revealed by the O K-edge sXAS. Our findings propose the critical influences of the partial covalency between oxygen 2p band and specific metal 3d band on the competition between intermediates displacement of the ORR, and thus highlight the importance of electronic structure in controlling oxide catalytic activity.

Health Assessment of Trace Metal Concentrations in Organic Fertilizer in Northern China.

The application of organic fertilizer could be accompanied by potential hazards to soil and humans caused by trace metals. A wide survey of organic fertilizers was carried out in northern China. A total of 117 organic fertilizer samples were collected to analyze the concentrations of seven trace metals. Simulation models were used to estimate the trace metal accumulation risk in soil and non-carcinogenic and carcinogenic risks to the human body. The concentrations of trace metals varied widely (Cr: 2.74⁻151.15; Ni: 2.94⁻49.35; Cu: 0.76⁻378.32; Zn: 0.50⁻1748.01; As: 1.54⁻23.96; Cd: 2.74⁻151.15; and Pb: 1.60⁻151.09 mg·kg-1). Chinese organic fertilizer standard limits were exceeded by0.85% for Cr, 5.98% for As, 1.71% for Cd, and 4.27% for Pb. Monte Carlo simulations showed that repeated application of organic fertilizer likely significantly increased the concentrations of Zn, Cd, and As in soil compared with the soil background levels according to the Soil Environmental Quality Standards of China. As and Cr pose high risks to human health, especially as carcinogenic risk factors with a skin exposure pathway. Reducing the content of Cr, Cu, Zn, As, and Cd in organic fertilizer would be of great significance for minimizing the damage caused by trace metals.

Charge Distribution on S and Intercluster Bond Evolution in Mo6S8 during the Electrochemical Insertion of Small Cations Studied by X-ray Absorption Spectroscopy.

Mo6S8 is regarded as a promising cathode material in rechargeable Mg batteries. Despite extensive studies, some fundamental questions are still unclarified, including the origination of the chemical stability, key factors inducing the structural evolution, and the factors determining the electrochemical reversibility. Herein Mo L2,3 and S K-edge X-ray absorption spectroscopy are utilized to uncover the underlying mechanism. Two kinds of S with different effective charge are found, indicating the nonuniform charge distribution. With one cation inserted, the charge distribution becomes homogeneous, relevant to the chemical stability and electrochemical reversibility. The structural evolution is attributed to the change of bond length induced by the delocalization of inserted cations. Moreover, the evolution of intercluster Mo-Mo bond length can be revealed by the drastic change of the S K pre-edge and is closely related to the electrochemical reversibility. This study can shed light on the aforementioned questions and guide the development of Mg cathode material.