Spin polarized Fe1-Ti pairs for highly efficient electroreduction nitrate to ammonia.

Electrochemical nitrate reduction to ammonia offers an attractive solution to environmental sustainability and clean energy production but suffers from the sluggish *NO hydrogenation with the spin-state transitions. Herein, we report that the manipulation of oxygen vacancies can contrive spin-polarized Fe1-Ti pairs on monolithic titanium electrode that exhibits an attractive NH3 yield rate of 272,000 µg h-1 mgFe-1 and a high NH3 Faradic efficiency of 95.2% at -0.4 V vs. RHE, far superior to the counterpart with spin-depressed Fe1-Ti pairs (51000 µg h-1 mgFe-1) and the mostly reported electrocatalysts. The unpaired spin electrons of Fe and Ti atoms can effectively interact with the key intermediates, facilitating the *NO hydrogenation. Coupling a flow-through electrolyzer with a membrane-based NH3 recovery unit, the simultaneous nitrate reduction and NH3 recovery was realized. This work offers a pioneering strategy for manipulating spin polarization of electrocatalysts within pair sites for nitrate wastewater treatment.

Highly Poison-Resistant Single-Atom Co-N4 Active Sites with Superior Operational Stability over 460 h for H2 S Catalytic Oxidation.

Efficient catalytic elimination of hydrogen sulfide (H2 S) with high activity and durability in nature gas and blast-furnace gas is very critical for both fundamental catalytic research and applied environmental chemistry. Herein, atomically dispersed Co atom catalysts with Co-N4 sites that can transform H2 S into S with conversion rate of ≈100% are designed and prepared. The representative 4Co-N/NC achieves a sulfur yield of nearly 100% and TOF(Co) of 869 h-1 at 180 °C. Importantly, remarkable long-term durability is achieved as well, with no obvious loss of catalytic activity in the run of 460 h, outperforming most of the reported catalysts. The short bond length and strong cooperation of Co-N are beneficial to improve the structural stability of the Co-N4 centers, and significantly enhanced resistance of water and sulfation over single-atom Co-catalyst. The present mechanism involves the stepwise hydrogen transfer process via the adsorbed *HOO and *HS intermediates.

Highly Active and Sulfur-Resistant Fe-N4 Sites in Porous Carbon Nitride for the Oxidation of H2 S into Elemental Sulfur.

Iron-based catalysts have been widely studied for the oxidation of H2 S into elemental S. However, the prevention of iron sites from deactivation remains a big challenge. Herein, a facile copolymerization strategy is proposed for the construction of isolated Fe sites confined in polymeric carbon nitride (CN) (Fe-CNNχ). The as-prepared Fe-CNNχ catalysts possess unique 2D structure as well as electronic property, resulting in enlarged exposure of active sites and enhancement of redox performance. Combining systematic characterizations with density functional theory calculation, it is disclosed that the isolated Fe atoms prefer to occupy four-coordinate doping configurations (Fe-N4 ). Such Fe-N4 centers favor the adsorption and activation of O2 and H2 S. As a consequence, Fe-CNNχ exhibit excellent catalytic activity for the catalytic oxidation of H2 S to S. More importantly, the Fe-CNNχ catalysts are resistant to water and sulfur poisoning, exhibiting outstanding catalytic stability (over 270 h of continuous operation), better than most of the reported catalysts.

Unraveling the mechanisms of S-doped carbon nitride for photocatalytic oxygen reduction to H2O2.

An in-depth understanding of the microscopic reaction mechanism on a nonmetal-doped catalytic system at the atomic level is one of the critical approaches to developing new efficient catalysts. Herein, the effects of S-doping on melon-based carbon nitride (CN) for the photocatalytic selective oxygen reduction reaction (ORR) have been comprehensively investigated by first-principles calculations. The configurations, electronic properties, optical properties, and the reaction performance of the S-doped melon-based CN have been studied and discussed. The results demonstrate that the decoration with S atoms exhibited substantial effects, involving the redistribution of the charge density and tuning of the bandgap, which promote the photocatalytic selective ORR activity. Accordingly, O2 is activated on the S-doped system with about 0.4 e of charge obtained from catalytic surfaces, leading to the thermodynamically feasible H2O2 and H2O formation, which is in good agreement with the experimental results. Our results provide theoretical insights into the design and development of polymeric carbon nitride (PCN) as well as other metal-free photocatalysts for the selective ORR.

Heteroatom Dopants Promote Two-Electron O2 Reduction for Photocatalytic Production of H2 O2 on Polymeric Carbon Nitride.

Polymeric carbon nitride modified with selected heteroatom dopants was prepared and used as a model photocatalyst to identify and understand the key mechanisms required for efficient photoproduction of H2 O2 via selective oxygen reduction reaction (ORR). The photochemical production of H2 O2 was achieved at a millimolar level per hour under visible-light irradiation along with 100 % apparent quantum yield (in 360-450 nm region) and 96 % selectivity in an electrochemical system (0.1 V vs. RHE). Spectroscopic analysis in spatiotemporal resolution and theoretical calculations revealed that the synergistic association of alkali and sulfur dopants in the polymeric matrix promoted the interlayer charge separation and polarization of trapped electrons for preferable oxygen capture and reduction in ORR kinetics. This work highlights the key features that are responsible for controlling the photocatalytic activity and selectivity toward the two-electron ORR, which should be the basis of further development of solar H2 O2 production.

Fluorescent Se-modified carbon nitride nanosheets as biomimetic catalases for free-radical scavenging.

Efficient biomimetic catalases have been broadly explored for free-radical scavenging and antioxidative stress. Herein, we introduce a non-toxic Se-modified carbon nitride (CN) nanosheet for this bioapplication, and it presents efficient catalase activity, high fluorescence properties, and good biocompatibility. These properties indicate that this material has potential for use as an artificial enzyme against oxidative stress.

The 100 most cited articles in ectopic pregnancy: a bibliometric analysis.

Ectopic pregnancy (EP) remains a major gynecological emergency and is a cause of morbidity or even mortality in women. As a consequence, top citation analysis of EP research in database of the Science Citation Index Expanded is needed to assess the publication trends of leading countries/territories and institutes as well as the research hotspots of EP. A total of 4881 articles relevant to EP were retrieved in the database of the Science Citation Index Expanded from 1965 to present, in which the 100 top-cited articles were selected for further analysis. The number of citations ranged from 81 to 482 (131.57 ± 69.76), with a time span of 40 years between 1969 and 2009. These citation classics came from 14 countries, and 65 of the articles came from the United States. Yale University in Connecticut led the list of classics with six papers. The 100 top-cited articles were published in 32 journals, in which the journal of Fertility and Sterility published the most (23 papers). Stovall TG and Ling FW published the highest number of studies (6 papers each). Articles that originated in the United States and that were published in high-impact journals were most likely to be cited in the field of EP research. Bibliometric analysis was used to provide a historical perspective on the progress in EP research over the past 50 years. Citation analysis is a feasible tool to comprehensively recognize the advances of EP research in the past and future research.

Tuning the charge states of CrW2O9 clusters deposited on perfect and defective MgO(001) surfaces with different color centers: A comprehensive DFT study.

The structures and electronic properties of bimetallic oxide CrW2O9 clusters supported on the perfect and defective MgO(001) surfaces with three different color centers, FS (0), FS (+), and FS (2+) centers, respectively, have been investigated by density functional theory calculations. Our results show that the configurations, adsorption energies, charge transfers, and bonding modes of dispersed CrW2O9 clusters are sensitive to the charge states of the FS centers. Compared with the gas-phase configuration, the CrW2O9 clusters supported on the defective surfaces are distorted dramatically, which exhibit different chain structures. On the perfect MgO surface, the depositions of clusters do not involve obvious charge transfer, while the situation is quite different on the defective MgO(001) surfaces in which significant electron transfer occurs from the surface to the cluster. Interestingly, this effect becomes more remarkable for electron-rich oxygen vacancies (FS (0) center) than that for electron-poor oxygen vacancies (FS (+) and FS (2+) centers). Furthermore, our work reveals a progressive Brønsted acid sites where spin density preferentially localized around the Cr atoms not the W atoms for all kinds of FS-centers, indicating the better catalytic activities can be expected for CrW2O9 cluster on defective MgO(001) surfaces with respect to the W3O9 cluster.

Serum salusin-ß levels are associated with the presence and severity of coronary artery disease.

OBJECTIVES: We sought to assess whether serum salusin-ß levels are correlated with the presence and severity of coronary artery disease (CAD). METHODS: We measured serum salusin-ß levels in 278 consecutive patients undergoing coronary angiography (CAG) for the evaluation of CAD and in 126 healthy controls. Serum salusin-ß levels were measured by enzyme-linked immunosorbent assay. The severity of CAD was assessed by angiographic coronary atherosclerosis index score system. RESULTS: Serum salusin-ß levels were significantly higher in patients undergoing CAG (n = 278) than those in healthy controls (n = 126) (3.81 ± 0.99 vs 4.34 ± 1.40 nmol/L, P < 0.01). In patients undergoing CAG, patients with CAD (n = 160) had significantly higher serum salusin-ß levels compared to patients without CAD (n = 118) (4.65 ± 1.44 vs 3.94 ± 1.23 nmol/L, P < 0.01). Multivariate logistic regression analysis revealed that serum salusin-ß levels were independently associated with the presence of CAD (odds ratio, 1.439; 95% confidence interval, 1.176-1.760; P < 0.01). Serum salusin-ß levels were positively correlated with the coronary atherosclerosis index score (r = 0.316, P < 0.001). CONCLUSIONS: Serum salusin-ß levels were associated with the presence and severity of CAD. Salusin-ß in serum might serve as a potential biomarker for reflecting the development and progression of CAD. Therapeutic treatment by inhibiting salusin-ß interaction to prevent CAD warrants further investigation.

Serum S100A12 concentrations are correlated with angiographic coronary lesion complexity in patients with coronary artery disease.

The neutrophil activation marker S100A12 is an important pro-inflammatory cytokine and a potential biomarker for a range of inflammatory diseases. This study aims to investigate whether serum S100A12 concentrations are associated with angiographic coronary lesion complexity in patients with coronary artery disease (CAD). We enrolled 240 CAD and 68 healthy controls. Coronary lesion complexity was assessed by coronary angiography (CAG). Serum S100A12 concentrations were detected by enzyme-linked immunosorbent assay (ELISA). We demonstrated that serum S100A12 concentrations were independently associated with the presence of complex lesion in patients with stable angina pectoris (SAP) (Odds ratio 1.02, 95% CI 1.01-1.04; p < 0.01). In addition, among patients with acute coronary syndrome (ACS) who had significantly higher serum S100A12 concentrations than SAP patients (140.8 [interval 109.4-208.6] vs. 120.8 [interval 96.1-145.9] µg/L, respectively, p < 0.01), those with multi-complex lesions had significantly higher serum S100A12 concentrations than those with no or one complex lesion (156.3 [interval 116.2-247.4] vs. 129.2 [interval 99.8-165.2] µg/L, respectively, p < 0.01). These findings suggest that S100A12 in serum might be a potential biomarker for providing valuable information regarding coronary plaque vulnerability in patients with CAD.

GABAB receptors resist acute desensitization in both postsynaptic and presynaptic compartments of periaqueductal gray neurons.

The ventrolateral midbrain periaqueductal gray (PAG) neurons have been intensively studied because of their pivotal role in the descending pain modulation system. Activation of GABAB receptors, one type of inhibitory G-protein-coupled receptors (GPCRs), in PAG neurons results in both presynaptic and postsynaptic inhibition. Acute desensitization is defined as rapid attenuation of receptor-mediated signaling. Recent studies report that multiple inhibitory GPCRs, including GABAB receptors, resist acute desensitization in the presynaptic but not postsynaptic compartments of certain neurons in mammal brains. In the present study, employing whole-cell voltage-clamp recordings on acute PAG slices from adult rats, we found that GABAB receptors resist acute desensitization to prolonged administration of baclofen (GABAB receptor agonist) in both presynaptic and postsynaptic compartments. The desensitization resistance of postsynaptic GABAB receptors was independent of presynaptic alteration and vice versa. The GABAB receptor-mediated inhibition at inhibitory presynaptic terminals also showed no desensitization. The results suggest that GABAB receptor-mediated inhibition remains functional in both postsynaptic and presynaptic compartments to sustained agonist administration in rat PAG neurons.

[Association of ABCG2 gene C421A polymorphism and susceptibility of primary gout in Han Chinese males].

OBJECTIVE: To assess the association between a C421A single nucleotide polymorphism (SNP) in exon 5 of ATP-binding cassette, sub-family G (WHITE), member 2 (ABCG2) gene and susceptibility of primary gout in Han Chinese males. METHODS: For 200 male patients with primary gout and 235 controls, the genotype of C421A locus was analyzed by PCR and direct sequencing. Blood glucose, uric acid, total cholesterol, triglycerides, creatinine and urea nitrogen was measured by an automatic biochemical analyzer. RESULTS: Compared with the controls, there was a higher frequency for AA genotype and A allele of the rs2231142 SNP in gout patients (22.5% vs. 8.5% by genotype; 44.9% vs. 32.3% by allele). The association with gout reached significance (chi-square =15.91, P< 0.001, crude OR=3.02, 95% CI:1.36-4.90 and OR (adjusted by age)=1.80, 95% CI: 1.32-2.45 by dominant mode; chi-square=6.82, P=0.009, OR=1.67, 95% CI: 1.54-2.27 by recessive mode). Blood glucose, uric acid, triglycerides, creatinine and urea nitrogen levels in gout patients were significantly higher than those of controls (P< 0.001). CONCLUSION: The C421A SNP, in particular AA phenotype, may be associated with susceptibility of primary gout in Han Chinese males.