MiR-449b-5p Ameliorates Hypoxia-induced Cardiomyocyte Injury through Activating PI3K/AKT Pathway by Targeting BCL2L13.

Recent reports show miR-449b-5p reduces liver and renal ischemia/reperfusion (I/R) injury, but its effects on hypoxia-induced cardiomyocyte injury in ischemic heart disease are still unknown. In this study, AC16 human cardiomyocytes underwent hypoxic conditions for durations of 24, 48, and 72 h. We observed that miR-449b-5p expression was significantly downregulated in hypoxic AC16 cardiomyocytes. Elevating the levels of miR-449b-5p in these cells resulted in enhanced cell survival, diminished release of LDH, and a reduction in cell apoptosis and oxidative stress using CCK-8, LDH assays, flow cytometry, TUNEL staining, and various commercial kits. Conversely, reducing miR-449b-5p levels resulted in the opposite effects. Through bioinformatics analysis and luciferase reporter assays, BCL2-like 13 (BCL2L13) was determined to be a direct target of miR-449b-5p. Inhibiting BCL2L13 greatly inhibited hypoxia-induced cell viability loss, LDH release, cell apoptosis, and excessive production of oxidative stress, whereas increasing BCL2L13 negated miR-449b-5p's protective impact in hypoxic AC16 cardiomyocytes. Additionally, miR-449b-5p elevated the levels of the proteins p-PI3K, p-AKT, and Bcl-2, while decreasing Bax expression in hypoxic AC16 cardiomyocytes by targeting BCL2L13. In summary, the research indicates that the protective effects of miR-449b-5p are facilitated through the activation of the PI3K/AKT pathway, which promotes cell survival, and by targeting BCL2L13, which inhibits apoptosis, offering a potential therapeutic strategy for ischemic heart disease by mitigating hypoxia-induced cardiomyocyte injury.

PEDF inhibits LPS-induced acute lung injury in rats and promotes lung epithelial cell survival by upregulating PPAR-γ.

BACKGROUND: The progression of acute lung injury (ALI) involves numerous pathological factors and complex mechanisms, and cause the destruction of epithelial and endothelial barriers. Pigment epithelium-derived factor (PEDF) is an angiogenesis inhibitor and a potential anti-inflammatory factor. The purpose of this study was to investigate the effect of PEDF on lipopolysaccharide (LPS)-induced ALI in rats. METHODS: In vivo, pathological and injury related factors examination were performed on rat lung to investigate the effect of PEDF on ALI. In vitro, the effect of PEDF on inflammatory injury and apoptosis of lung epithelial type II RLE-6TN cell was evaluated, and the expression of inflammatory factors and related pathway proteins and PPAR-γ (in the presence or absence of PPAR-γ inhibitors) were analyzed. RESULTS: In vivo results showed that PEDF inhibited the inflammatory factor expression (TNF-α, IL-6 and IL-1ß) and progression of ALI and reduced lung cell apoptosis in rats. In vitro results showed that PEDF could effectively inhibit LPS-stimulated inflammatory damage and apoptosis of RLE-6TN cells. PEDF inhibited the RLE-6TN cell injury by enhancing the expression of PPAR-γ. CONCLUSIONS: PEDF is an anti-inflammatory factor, which can inhibit apoptosis of lung epithelial cells by upregulating the expression of PPAR-γ and reducing LPS-induced ALI in rats.

Bubble-Mediated Large-Scale Hierarchical Assembly of Ultrathin Pt Nanowire Network Monolayer at Gas/Liquid Interfaces.

Extensive macroscale two-dimensional (2-D) platinum (Pt) nanowire network (NWN) sheets are created through a hierarchical self-assembly process with the aid of biomolecular ligands. The Pt NWN sheet is assembled from the attachment growth of 1.9 nm-sized 0-D nanocrystals into 1-D nanowires featuring a high density of grain boundaries, which then interconnect to form monolayer network structures extending into centimeter-scale size. Further investigation into the formation mechanism reveals that the initial emergence of NWN sheets occurs at the gas/liquid interfaces of the bubbles produced by sodium borohydride (NaBH4) during the synthesis process. Upon the rupture of these bubbles, an exocytosis-like process releases the Pt NWN sheets at the gas/liquid surface, which subsequently merge into a continuous monolayer Pt NWN sheet. The Pt NWN sheets exhibit outstanding oxygen reduction reaction (ORR) activities, with specific and mass activities 12.0 times and 21.2 times greater, respectively, than those of current state-of-the-art commercial Pt/C electrocatalysts.

Construction and validation of a predictive model for the risk of three-month-postoperative malnutrition in patients with gastric cancer: a retrospective case-control study.

Background: This study analyzed both the influencing factors of malnutrition in patients with gastric cancer and established a multi-dimensional risk model to predict postoperative malnutrition three months after surgery. Methods: The clinical data of gastric cancer patients hospitalized for the first time and receiving laparoscopic surgery in the general surgery department of our hospital were retrospectively analyzed through the hospital information system and divided into a training set and a validation set in the ratio of 7:3. Nutritional status was assessed using the Patient Generated Subjective Global Assessment scale and follow-up records three months after surgery. Patients were divided into a non-malnutrition group and a malnutrition group, and a risk prediction model was established and displayed in the form of a nomogram. Results: A total of 344 patients were included, with 242 in the training and 102 in the validation set. Tumor node metastasis stage (TNM Stage, P=0.020), cardiac function grading (CFG, P=0.013), prealbumin (PAB, P<0.001), neutrophil-to-lymphocyte ratio (NLR, P=0.027), and enteral nutrition within 48 hours post-operation (EN 48 h post-op, P=0.025) were independent risk factors. We established a prediction model with the above variables and displayed it via a nomogram, then verified its effectiveness through internal and external verification. This revealed a C-index of 0.84 (95% CI: 0.79-0.89), and the area under curve (AUC) areas of 0.840 (training set) and 0.854 (validation set), which was better than the nutritional risk screening 2002 (NRS2002) scale. The calibration curve brier scores were 0.159 and 0.195, and the Hosmer-Lemeshow test chi-square values were 14.070 and 1.989 (P>0.05). The decision curve analysis (DCA) of the training set model indicated the clinical applicability was good and within the threshold probability range of 10%-85%, which was also better than NRS2002. Conclusions: A clinical prediction model including multi-dimensional variables was established based on independent risk factors of malnutrition three months after gastrectomy in patients with gastric cancer. The model yields greater prediction accuracy of the risk of three-month-postoperative malnutrition in patients with gastric cancer, helps screen high-risk patients, formulates targeted nutritional prescriptions early, and improves the overall prognosis of patients.

Effects of Dapagliflozin in Combination with Metoprolol Sustained-Release Tablets on Prognosis and Cardiac Function in Patients with Acute Myocardial Infarction after PCI.

Objective: To find the effects of dapagliflozin in combination with metoprolol sustained-release tablets on cardiac function and prognosis in acute myocardial infarction patients after PCI. Methods: A total of 84 patients with myocardial infarction who experienced PCI from February 2020 to February 2022 were included and allocated into 3 groups: groups A, B, and C (n = 28/per group). Group A was given dapagliflozin combined with metoprolol sustained-release tablets, group B was given dapagliflozin, and group C was given the placebo. Left ventricular end diastolic diameter (EDD), left ventricular ejection fraction (LVEF), and end systolic diameter (ESD) were measured before and after treatment in all groups; myocardial infarction areas were matched among all three groups at 3 months posttreatment. The serum concentrations of interleukin-6 (IL-6), hypersensitive C-reactive protein (hs-CRP), superoxide dismutase (SOD), and malondialdehyde (MDA) were detected in all three groups before and after treatment. The levels of N-terminal probrain natriuretic peptide (NT-pro BNP), lipoprotein (a) (Lp(a)), ischemia-modified albumin (IMA), and secreted frizzled-related protein 5 (SFRP5) were also detected in the serum of all groups. Adverse reactions and cardiovascular adverse events were matched between all groups. Results: The levels of LVEF in groups A and B were increased after treatment, while the levels of EDD and ESD were decreased. The improvement degree of LVEF and EDD levels in groups A and B was found greater compared to group C (P < 0.05). No significant difference was found in myocardial infarction area among the three groups at 3 months postoperation (P > 0.05). Serum concentrations of MDA, hs-CRP, IL-6, IMA, NT-proBNP, and Lp(a) were found to decrease in all three groups after treatment, while the levels of SOD and SFRP5 were increased. The improvement degree of serum hs-CRP, IL-6, SOD, MDA, IMA, NT-proBNP, Lp(a), and SFRP5 levels was greater in both groups A and B compared to group C. The improvement degree of serum hS-CRP, SOD, MDA, IMA, Nt-probNP, Lp(a), and SFRP5 levels was significantly greater in group A compared to group B (P < 0.05). No adverse effect was observed in all three groups (P > 0.05). Total occurrence of cardiovascular adverse effects such as stent thrombosis, heart failure, ventricular fibrillation, and death was 10.71% in group A, 25.00% in group B, and 53.75% in group C. There was statistical significance in the onset of cardiovascular adverse effects 3 months postoperation among all three groups (P < 0.05). Conclusion: Dapagliflozin with metoprolol sustained-release tablets can be effective in improving the heart function, inflammatory response, oxidative stress response, and prognosis in patients after PCI.

Study on the predictive ability of emergency CHADS2 score and CHA2DS2-VASc score for coronary artery disease and prognosis in patients with acute ST-segment elevation myocardial infarction.

Background: Acute ST-segment elevation myocardial infarction (STEMI) has a high morbidity and mortality rate. The congestive heart failure, hypertension, age, diabetes, previous stroke/transient ischemic attack (2 points) (CHADS2) and CHADS2 score with 2 points assigned for age >75 years-vascular disease (CHA2DS2-VASc) scores are widely used for risk stratification management of non-valvular atrial fibrillation stroke and have high prognostic value in cardiovascular disease. This study aims to investigate the predictive value of the emergency CHADS2 and CHA2DS2-VASc score on coronary artery lesions and prognosis in patients with acute STEMI. Methods: A total of 524 patients with STEMI from May 2018 to October 2021 were selected for emergency CHADS2 and CHA2DS2-VASc. Clinical data and laboratory indicators were collected. Patients were evaluated for coronary artery disease (CAD) and prognosis. Logistic regression and the receiver operating characteristic (ROC) curve were used to analyze the data. Results: In severe group, CysC levels, CHADS2, CHA2DS2-VASc score and the proportion of diabetes, stroke or transient ischemic attack (TIA), congestive heart failure, smoking history, Killip class ≥2 was higher than that in mild and moderate group. In poor prognosis group, levels of serum creatinine (Crea), CysC, hemoglobin (Hb), CHADS2, CHA2DS2-VASc score and the proportion of hypertension, diabetes, stroke or TIA, congestive heart failure, smoking history, and Killip class ≥2 was higher than that in good prognosis group. Diabetes (OR, 3.678; 95% CI: 2.876-5.872, 0.008), CHADS2 (OR, 3.829; 95% CI: 2.310-5.832, 0.003) and CHA2DS2-VASc score (OR, 4.671; 95% CI: 3.125-6.187, 0.000) were independent risk factors for the severity of CAD (P<0.05). Diabetes (OR, 3.287; 95% CI: 2.231-5.123, 0.012), Killip class ≥2 (OR, 2.212; 95% CI: 1.023-2.987, 0.045), LVEF (OR, 3.110; 95% CI: 2.124-5.031, 0.023), CHADS2 (OR, 3.228; 95% CI: 2.133-5.886, 0.005) and CHA2DS2-VASc score (OR, 3.988; 95% CI: 2.987-5.873, 0.001) were independent risk factors for prognosis of acute STEMI patients. Area under curve (AUC) value of CHA2DS2-VASc score in evaluating CAD and prognosis was 0.947, 0.931, higher than that of the CHADS2 score (0.836, 0.812) (P<0.05). Conclusions: Multiple factors jointly affect the severity and prognosis of CAD in patients with acute STEMI. The CHA2DS2-VASc score is better than the CHADS2 score in predicting the severity of coronary artery lesions and prognosis of patients, providing theoretical support for clinical practice.

Graphene-nanopocket-encaged PtCo nanocatalysts for highly durable fuel cell operation under demanding ultralow-Pt-loading conditions.

The proton exchange membrane fuel cell (PEMFC) as an attractive clean power source can promise a carbon-neutral future, but the widespread adoption of PEMFCs requires a substantial reduction in the usage of the costly platinum group metal (PGM) catalysts. Ultrafine nanocatalysts are essential to provide sufficient catalytic sites at a reduced PGM loading, but are fundamentally less stable and prone to substantial size growth in long-term operations. Here we report the design of a graphene-nanopocket-encaged platinum cobalt (PtCo@Gnp) nanocatalyst with good electrochemical accessibility and exceptional durability under a demanding ultralow PGM loading (0.070 mgPGM cm-2) due to the non-contacting enclosure of graphene nanopockets. The PtCo@Gnp delivers a state-of-the-art mass activity of 1.21 A mgPGM-1, a rated power of 13.2 W mgPGM-1 and a mass activity retention of 73% after an accelerated durability test. With the greatly improved rated power and durability, we project a 6.8 gPGM loading for a 90 kW PEMFC vehicle, which approaches that used in a typical catalytic converter.

Preventive Effect Observation of Dapagliflozin on Middle and Later Ventricular Remodeling in Patients with Acute ST Segment Elevation Anterior Wall Myocardial Infarction: A Single-Center, Retrospective Cohort Study.

Objective: This study aimed to observe the effect of dapagliflozin on left ventricular ejection function (LVEF) and left ventricular end-diastolic volume (LVEDV) in patients with acute anesthesia ST segment elevation myocardial infarction (ASTEMI) and explore the effect of prophylactic treatment on ventricular remodeling (VR). Methods. A retrospective cohort design was employed to collect 188 patients with anterior wall STEMI who received emergency percutaneous coronary intervention (PCI). The patients were divided into dapagliflozin group and control group. The baseline data, the results of echocardiography at 6 months and on admission, and the proportion of VR were compared between the two groups. Echocardiography followed up for the two groups for 6 months after PCI and VR (LVEDV increased ≥20%) were considered the main clinical outcomes. Single-factor and multifactor logistic regression was conducted to explore the preventive effect of dapagliflozin on VR in patients with anterior wall STEMI. Results. There were significant differences in gender, history of diabetes, glycosylated hemoglobin (Hb1AC), admission LVEF, Killip grade of heart failure, and brain natriuretic peptide (BNP) between the dapagliflozin group and the control group regarding the baseline data. Compared with the results of echocardiography at admission and 6 months, the decrease in LVEDV and the increase of LVEF at 6 months in the dapagliflozin group were significantly higher than those in the control group. During the follow-up of 6 months, the VR rate in the dapagliflozin group was significantly lower than that in the control group. Multifactor logistic regression analysis suggested that the risk of VR was reduced by taking dapagliflozin after the adjustment of the confounding factors. Additionally, the combined use of dapagliflozin, ACEI/ARB, and ß-block can further reduce the risk. Conclusion. Regular taking of dapagliflozin has a positive effect on the improvement of middle and LVEF and left ventricular volume enlargement in patients with anterior wall STEMI, as well as the prevention of the occurrence of VR.

An Application of Fuzzy Analytic Hierarchy Process in Risk Evaluation Model.

Conflicts in land exploration are incisive social problems which have been the subject in many studies. Risk assessment of land conflicts is effective to resolve such problems. Specifically, fuzzy mathematics and the analytic hierarchy process were combined together to evaluate risk in land conflicts in our work, which is proved useful to solve uncertainty and imprecision problems. Based on the analysis of the principles for the risk assessment of a land conflicts index system, a set of risk assessment indexes using the fuzzy analytic hierarchy process (FAHP) was presented. The results show that the overall risk is at medium level, and the risk of the feasibility index and controllability index need to be paid more attention to. The contribution of this article is reflected in two aspects: (1) the application of FAHP in risk assessments of land conflicts is effective and valid; (2) it is helpful for governments to establish a stricter management system of work safety for conflicts in land exploration based on the risk assessment results.

Risk Prediction Model Based on Biomarkers of Remodeling in Patients with Acute Anterior ST-Segment Elevation Myocardial Infarction.

BACKGROUND The aim of the present study was to develop a risk prediction model in patients with acute anterior ST-segment elevation myocardial infarction (STEMI). MATERIAL AND METHODS Clinical data from 333 patients with acute anterior STEMI were retrospectively analyzed. Clinical echocardiographic and angiographic data from patients with left ventricular remodeling (LVR) and those without LVR were compared. Factors that influenced risk were identified using multivariate logistic regression analysis. The area under the curve (AUC) of the receiver operating characteristic curve was used to assess the diagnostic performance of the model. RESULTS After 6-month follow-up, 135 of the patients experienced LVR (LVR group), whereas 198 did not (non-LVR group). Results of multivariate analysis showed that the number of stenosed coronary vessels, left ventricular end-diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), transforming growth factor-beta (TGF-ß) at admission, and cardiac troponin I 3 days after admission (3-d cTnI) were all factors predictive of LVR in patients with acute anterior STEMI (all P<0.05). The established prediction model was Y=-20.639+0.711×number of stenosed coronary vessels + 0.137×LVEDV-0.129×LVEF+0.026×TGF-ß at admission + 0.162×3-d cTnI. The estimated AUC of this model was 0.978 (95% confidence interval [CI] 0.955-0.991), significantly superior to the single-factor numbers for stenosed coronary vessel of 0.650 (95% CI 0.597-0.702), LVEDV of 0.876 (95% CI 0.836-0.910), LVEF of 0.684 (95% CI 0.631-0.734), TGF-ß at admission of 0.696 (95% CI 0.644-0.745), cTnI at admission of 0.913 (95% CI 0.877-0.941), and 3-d cTnI of 0.945 (95% CI 0.914-0.967). CONCLUSIONS The established model had excellent diagnostic accuracy for predicting LVR in patients with acute anterior STEMI.

Toward Rational Design of Single-Atom Catalysts.

Downscaling catalyst size has long been used to promote the atomic utilization efficiency of catalysts. Single-atom catalysts (SACs) are the current end of this downscaling road, offering the potential of 100% metal atom utilization and excellent catalytic behavior compared with traditional nanoparticle catalysts. However, most development of SACs still relies on trial-and-error experiments because of the insufficient understanding of the distinctive properties of SACs and their structure-activity relationships. This Perspective discusses the path forward toward the rational design of SACs through a summary of understanding regarding the distinctive properties of single-atom active sites, their dynamic changes during the reactions, and the corresponding reaction mechanisms. Major challenges and opportunities for future research on SACs are identified in precisely controlled synthesis, advanced operando characterizations, and discovering the unconventional catalytic mechanisms.

Beyond Extended Surfaces: Understanding the Oxygen Reduction Reaction on Nanocatalysts.

Increasing the platinum utilization efficiency is the key to the advancement and broad dissemination of proton-exchange-membrane fuel cells (PEMFCs). Central to the task is the creation of highly active and durable Pt-based catalysts for the cathodic oxygen reduction reaction (ORR), which demands a comprehensive understanding of the ORR processes on these catalysts under reaction conditions. Past efforts have accumulated a vast wealth of knowledge of the ORR on extended Pt and Pt-alloy model surfaces. While the knowledge has been applied to understanding and designing ORR catalysts, it has also been recognized that these understandings cannot always translate into nanoscale systems. In this Perspective, we will review the progress that the theoretical descriptor has evolved to reconcile the observed differences between extended and nanoscale Pt surfaces, and we highlight the needs in advancing both characterizations and theories in order to understand ORR in the more complex Pt-alloy nanocatalysts. Particularly, understanding the dynamic structure-composition-function relation of Pt-alloy nanocatalysts during ORR demands concerted efforts in precision synthesis, advanced atomistic-scale in situ characterization, and comprehensive computational models.

Pt-Based Nanocrystal for Electrocatalytic Oxygen Reduction.

Currently, Pt-based electrocatalysts are adopted in the practical proton exchange membrane fuel cell (PEMFC), which converts the energy stored in hydrogen and oxygen into electrical power. However, the broad implementation of the PEMFC, like replacing the internal combustion engine in the present automobile fleet, sets a requirement for less Pt loading compared to current devices. In principle, the requirement needs the Pt-based catalyst to be more active and stable. Two main strategies, engineering of the electronic (d-band) structure (including controlling surface facet, tuning surface composition, and engineering surface strain) and optimizing the reactant adsorption sites are discussed and categorized based on the fundamental working principle. In addition, general routes for improving the electrochemical surface area, which improves activity normalized by the unit mass of precious group metal/platinum group metal, and stability of the electrocatalyst are also discussed. Furthermore, the recent progress of full fuel cell tests of novel electrocatalysts is summarized. It is suggested that a better understanding of the reactant/intermediate adsorption, electron transfer, and desorption occurring at the electrolyte-electrode interface is necessary to fully comprehend these electrified surface reactions, and standardized membrane electrode assembly (MEA) testing protocols should be practiced, and data with full parameters detailed, for reliable evaluation of catalyst functions in devices.

Unifying the Hydrogen Evolution and Oxidation Reactions Kinetics in Base by Identifying the Catalytic Roles of Hydroxyl-Water-Cation Adducts.

Despite the fundamental and practical significance of the hydrogen evolution and oxidation reactions (HER/HOR), their kinetics in base remain unclear. Herein, we show that the alkaline HER/HOR kinetics can be unified by the catalytic roles of the adsorbed hydroxyl (OHad)-water-alkali metal cation (AM+) adducts, on the basis of the observations that enriching the OHad abundance via surface Ni benefits the HER/HOR; increasing the AM+ concentration only promotes the HER, while varying the identity of AM+ affects both HER/HOR. The presence of OHad-(H2O) x-AM+ in the double-layer region facilitates the OHad removal into the bulk, forming OH--(H2O) x-AM+ as per the hard-soft acid-base theory, thereby selectively promoting the HER. It can be detrimental to the HOR as per the bifunctional mechanism, as the AM+ destabilizes the OHad, which is further supported by the CO oxidation results. This new notion may be important for alkaline electrochemistry.

Surface-Engineered PtNi-O Nanostructure with Record-High Performance for Electrocatalytic Hydrogen Evolution Reaction.

Hydrogen holds the potential of replacing nonrenewable fossil fuel. Improving the efficiency of hydrogen evolution reaction (HER) is critical for environmental friendly hydrogen generation through electrochemical or photoelectrochemical water splitting. Here we report the surface-engineered PtNi-O nanoparticles with enriched NiO/PtNi interface on surface. Notably, PtNi-O/C showed a mass activity of 7.23 mA/µg at an overpotential of 70 mV, which is 7.9 times higher compared to that of the commercial Pt/C, representing the highest reported mass activity for HER in alkaline conditions. The HER overpotential can be lowered to 39.8 mV at 10 mA/cm2 when platinum loading was only 5.1 µgpt/cm2, showing exceptional HER efficiency. Meanwhile, the prepared PtNi-O/C nanostructures demonstrated significantly improved stability as well as high current performance which are well over those of the commercial Pt/C and demonstrated capability of scaled hydrogen generation.

Roles of Mo Surface Dopants in Enhancing the ORR Performance of Octahedral PtNi Nanoparticles.

Doping with a transition metal was recently shown to greatly boost the activity and durability of PtNi/C octahedral nanoparticles (NPs) for the oxygen reduction reaction (ORR), but its specific roles remain unclear. By combining electrochemistry, ex situ and in situ spectroscopic techniques, density functional theory calculations, and a newly developed kinetic Monte Carlo model, we showed that Mo atoms are preferentially located on the vertex and edge sites of Mo-PtNi/C in the form of oxides, which are stable within the wide potential window of the electrochemical cycle. These surface Mo oxides stabilize adjacent Pt sites, hereby stabilizing the octahedral shape enriched with (111) facets, and lead to increased concentration of Ni in subsurface layers where they are protected against acid dissolution. Consequently, the favorable Pt3Ni(111) structure for the ORR is stabilized on the surface of PtNi/C NPs in acid against voltage cycling. Significantly, the unusual potential-dependent oxygen coverage trend on Mo-doped PtNi/C NPs as revealed by the surface-sensitive Δµ analysis suggests that the Mo dopants may also improve the ORR kinetics by modifying the coordination environments of Pt atoms on the surface. Our studies point out a possible way to stabilize the favorable shape and composition established on conceptual catalytic models in practical nanoscale catalysts.

Inorganic sulfur and mercury speciation in the water level fluctuation zone of the Three Gorges Reservoir, China: The role of inorganic reduced sulfur on mercury methylation.

The water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China is a unique geomorphological unit that undergoes annual flooding and drying alternation cycle. The alternating redox conditions within the WLFZ are expected to result in dynamic cycling of reduced sulfur species, which could affect mercury (Hg) methylation due to the high affinity of reduced sulfur species to both inorganic divalent mercury (Hg(II)i) and methylmercury (MeHg). Variations of inorganic sulfur species (measured as acid volatile sulfide, chromium reductive sulfur, elemental sulfur, and water-soluble sulfate), total mercury (THg) and MeHg were studied at two typical WLFZ sites in the TGR from July 2015 to June 2016. Whereas the water-soluble sulfate contents stayed essentially constant, the reduced inorganic sulfur contents varied greatly as the water level changed. Compared with the control soils, the MeHg contents in the WLFZ soils increased, suggesting that water level fluctuations accelerated the methylation process of Hg(II)i. In situ Hg(II)i-methylation also appeared to occur in the sub-layer of the drained sediment during the draw-down season. The significant correlation between MeHg and elemental sulfur (S(0)) further suggests that polysulfides may have played a role in Hg(II)i-methylation by increasing the bioavailable Hg(II)i content in the WLFZ of the TGR.

Dominating Role of Ni0 on the Interface of Ni/NiO for Enhanced Hydrogen Evolution Reaction.

The research of a robust catalytic system based on single NiOx electrocatalyst for hydrogen evolution reaction (HER) remains a huge challenge. Particularly, the factors that dominate the catalytic properties of NiOx-based hybrids for HER have not been clearly demonstrated. Herein, a convenient protocol for the fabrication of NiOx@bamboo-like carbon nanotube hybrids (NiOx@BCNTs) is designed. The hybrids exhibit superb catalytic ability and considerable durability in alkaline solution. A benchmark HER current density of 10 mA cm-2 has been achieved at an overpotential of ∼79 mV. In combination with the experimental results and density functional theory (DFT) calculations, this for the first time definitely validates that the inherent high Ni0 ratio and the Ni0 on the interface of Ni/NiO play a vital role in the outstanding catalytic performance. Especially, the Ni0 on the interface of Ni/NiO performs superior activity for water splitting compared with that of bulk Ni0. These conclusions provide guidance for the rational design of the future non-noble metallic catalysts.

Composition tunable ternary Pt-Ni-Co octahedra for optimized oxygen reduction activity.

Herein, we report a one-step synthesis method for octahedral Pt-Ni-Co ternary catalysts with tunable compositions and fixed shapes. Impressively, the composition optimized octahedral PtNi0.55Co0.1/C demonstrated a significant improvement in ORR activity compared to those of previously reported Pt-Ni-Co alloy octahedra, showing an outstanding specific activity of 5.05 mA cm-2 and a mass activity of 2.80 mA µgPt-1, which are around 20.2 times and 14.7 times higher than those of the commercial Pt/C catalyst (0.25 mA cm-2 and 0.19 mA µgPt-1).