Design Strategies towards Advanced Hydrogen Evolution Reaction Electrocatalysts at Large Current Densities.

Hydrogen (H2), produced by water electrolysis with the electricity from renewable sources, is an ideal energy carrier for achieving a carbon-neutral and sustainable society. Hydrogen evolution reaction (HER) is the cathodic half-reaction of water electrolysis, which requires active and robust electrocatalysts to reduce the energy consumption for H2 generation. Despite numerous electrocatalysts have been reported by the academia for HER, most of them were only tested under relatively small current densities for a short period, which cannot meet the requirements for industrial water electrolysis. To bridge the gap between academia and industry, it is crucial to develop highly active HER electrocatalysts which can operate at large current densities for a long time. In this review, the mechanisms of HER in acidic and alkaline electrolytes are firstly introduced. Then, design strategies towards high-performance large-current-density HER electrocatalysts from five aspects including number of active sites, intrinsic activity of each site, charge transfer, mass transfer, and stability are discussed via featured examples. Finally, our own insights about the challenges and future opportunities in this emerging field are presented.

Computational Screening of Two-Dimensional Metal-Organic Frameworks as Efficient Single-Atom Catalysts for Oxygen Reduction Reaction.

The development of efficient and inexpensive oxygen reduction reaction (ORR) catalysts is crucial for renewable energy technologies. Herein, using density functional theory (DFT) methods and microkinetic simulations, we systematically investigated the ORR catalytic performance of a series of 2D metal-organic frameworks M3 (HADQ)2 (HADQ=2,3,6,7,10,11-hexaamine dipyrazino quinoxaline). It shows that all 2D M3 (HADQ)2 (M=Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh and Pd) monolayers are metallic, due to π-conjugated crystal orbitals centered on the central metals and ligand N atoms. The catalytic activity of M3 (HADQ)2 depends on the binding strength between ORR intermediates and metal species, and can be tuned via changing the central metals. Among these candidates, Rh3 (HADQ)2 and Co3 (HADQ)2 show superior ORR performance to Pt (111) with high half-wave potentials of 0.99 and 0.93 V, respectively. Moreover, the screened two catalysts have excellent intermediate-tolerance ability for dynamic coverage of oxygenated species on the active sites. Our work provides a new path towards developing efficient ORR electrocatalysts.

Self-Supported Ru-Incorporated NiSe2 for Ampere-Level Current Density Hydrogen Evolution.

To meet the requirements for industrial water splitting to generate hydrogen, it is urgent, but still quite challenging to develop highly active and stable electrocatalysts for large-current-density hydrogen evolution reaction (HER). Herein, Ru-incorporated NiSe2 (Ru-NiSe2 ) was designed and synthesized. The introduction of Ru results in the formation of hierarchically structured Ru-NiSe2 with large electrochemical active surface area, and well-modified electronic structure. As expected, the as-fabricated Ru-NiSe2 displays impressive HER activity in 1.0 M KOH, with a low overpotential of 180.8 mV to reach the current density of 1000 mA cm-2 . Ru-NiSe2 also presents outstanding long-term stability at high current densities, owing to its high intrinsic chemical stability, and strong catalyst-support interface. Notably, when performed at a certain current density of 1000 mA cm-2 , the overpotential increase after 90 h is only 13 mV. Such excellent HER performance of Ru-NiSe2 demonstrates its great potential for practical use in industrial water splitting.

Regulatory effect and mechanism of LncRNA SOX2OT in idiopathic pulmonary fibrosis.

This study discusses the role played by long noncoding RNA (lncRNA) SOX2OT (SOX2OT) in idiopathic pulmonary fibrosis (IPF). By inducing human embryonic lung fibroblasts (MRC5) through hypoxia, the researchers observed changes in SOX2OT expression and fibrotic processes during hypoxia. Moreover, SOX2OT abnormal expression vectors were constructed and transfected into MRC5 to analyze the effect of SOX2OT on MRC5. The results showed that the expression levels of SOX2OT and α-SMA were elevated under hypoxic conditions and were positively correlated (P<0.05). α-SMA, Collagen I and Collagen III protein expression and SOX2OT levels all increased under hypoxia (P<0.05). Finally, silencing SOX2OT expression led to weakened MRC5 proliferation, inhibited fibrosis process, and reduced inflammation (P<0.05). In conclusion, SOX2OT is closely related to the occurrence and development of IPF, and silencing its expression can inhibit fibrosis progression.

Curcumin ameliorates pulmonary fibrosis progression by inhibiting the fibrotic process of lung fibroblasts.

The objective of this study was to analyze the effect of curcumin (Cur) on pulmonary fibrosis (PF), so as to provide new clinical evidence for future PF treatment. To achieve these goals, the researchers set up bought human lung fibroblasts MRC-5 as a control group without treatment, a model group for PF cell modeling, and an intervention group for Cur intervention after PF modeling. Cell proliferation capacity and cellular TGF-ß1, α-SMA, Collagen I, Collagen III, Bax, N-cadherin and E-cadherin protein expression were determined. The results show that markedly enhanced cell proliferation capacity and TGF-ß1, α-SMA, Collagen I and Collagen III protein levels were observed in the model group, while the cell activity and fibrosis degree in the intervention group were significantly decreased compared with the model group (P<0.05). In addition, the intervention group exhibited lower N-cadherin and Bax with higher E-cadherin than the model group (P<0.05). In addition, the team found that the inflammatory response and oxidative stress were also more significantly improved in the intervention group (P<0.05). These experimental results tell us that Cur can ameliorate the fibrotic process of PF by inhibiting the activity of MRC-5.

Enabling Superior Electrochemical Properties for Highly Efficient Potassium Storage by Impregnating Ultrafine Sb Nanocrystals within Nanochannel-Containing Carbon Nanofibers.

Sb-based nanocomposites are attractive anode materials for batteries as they exhibit large theoretical capacity and impressive working voltage. However, tardy potassium ion diffusion characteristics, unstable Sb/electrolyte interphase, and huge volume variation pose a challenge, hindering their practical use for potassium-ion batteries (PIBs). Now, a simple robust strategy is presented for uniformly impregnating ultrasmall Sb nanocrystals within carbon nanofibers containing an array of hollow nanochannels (denoted u-Sb@CNFs), resolving the issues above and yielding high-performance PIBs. u-Sb@CNFs can be directly employed as an anode, thereby dispensing with the need for conductive additives and binders. Such a judiciously crafted u-Sb@CNF-based anode renders a set of intriguing electrochemical properties, representing large charge capacity, unprecedented cycling stability, and outstanding rate performance. A reversible capacity of 225 mAh g-1 is retained after 2000 cycles at 1 A g-1 .

Tuning the Electron Localization of Gold Enables the Control of Nitrogen-to-Ammonia Fixation.

The (photo)electrochemical N2 reduction reaction (NRR) provides a favorable avenue for the production of NH3 using renewable energy in mild operating conditions. Understanding and building an efficient catalyst with high NH3 selectivity represents an area of intense interest for the early stages of development for NRR. Herein, we introduce a CoOx layer to tune the local electronic structure of Au nanoparticles with positive valence sites for boosting conversion of N2 to NH3 . The catalysts, possessing high average oxidation states (ca. 40 %), achieve a high NH3 yield rate of 15.1 µg cm-2 h-1 and a good faradic efficiency of 19 % at -0.5 V versus reversible hydrogen electrode. Experimental results and simulations reveal that the ability to tune the oxidation state of Au enables the control of N2 adsorption and the concomitant energy barrier of NRR. Altering the Au oxidation state provides a unique strategy for control of NRR in the production of valuable NH3 .

Bridging the Surface Charge and Catalytic Activity of a Defective Carbon Electrocatalyst.

Electrocatalysis is dominated by reaction at the solid-liquid-gas interface; surface properties of electrocatalysts determine the electrochemical behavior. The surface charge of active sites on catalysts modulate adsorption and desorption of intermediates. However, there is no direct evidence to bridge surface charge and catalytic activity of active sites. Defects (active sites) were created on a HOPG (highly oriented pyrolytic graphite) surface that broke the intrinsic sp2 -hybridization of graphite by plasma, inducing localization of surface charge onto defective active sites, as shown by scanning ion conductance microscopy (SICM) and Kelvin probe force microscopy (KPFM). An electrochemical test revealed enhanced intrinsic activity by the localized surface charge. DFT calculations confirmed the relationship between surface charge and catalytic activity. This work correlates surface charge and catalytic activity, providing insights into electrocatalytic behavior and guiding the design of advanced electrocatalysts.

PdSeO3 Monolayer: Promising Inorganic 2D Photocatalyst for Direct Overall Water Splitting Without Using Sacrificial Reagents and Cocatalysts.

Direct production of H2 from photocatalytic water splitting is a potential solution to environmental pollution and energy crisis, and tremendous efforts have been made to seek efficient photocatalysts that can split pure water (pH = 7) under visible light irradiation. Herein, by means of systematic density functional theory (DFT) computations, we demonstrated that the two-dimensional (2D) PdSeO3 monolayer is a promising candidate. The mechanical exfoliation of PdSeO3 monolayer from its bulk phase is experimentally feasible due to the rather small cleavage energy of ∼0.42 J/m2. Remarkably, PdSeO3 monolayer is semiconducting with a moderate indirect band gap of 2.84 eV, and its valence and conduction bands perfectly engulf the redox potentials of water. In particular, water oxidation and hydrogen reduction half reactions can both occur readily on the different active sites of PdSeO3 monolayer under the potentials solely provided by photogenerated electrons and holes. As PdSeO3 monolayer also has rather pronounced optical absorption in the visible and ultraviolet regions of the solar spectrum, it could be utilized as a highly efficient photocatalyst for splitting pure water into H2 and O2 in a stoichiometric amount of 2:1 without using sacrificial reagents or cocatalysts.

Tuning Surface Electronic Configuration of NiFe LDHs Nanosheets by Introducing Cation Vacancies (Fe or Ni) as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction.

Intrinsically inferior electrocatalytic activity of NiFe layered double hydroxides (LDHs) nanosheets is considered as a limiting factor to inhibit the electrocatalytic properties for oxygen evolution reaction (OER). Proper defect engineering to tune the surface electronic configuration of electrocatalysts may significantly improve the intrinsic activity. In this work, the selective formation of cation vacancies in NiFe LDHs nanosheets is successfully realized. The as-synthesized NiFe LDHs-VFe and NiFe LDHs-VNi electrocatalysts show excellent activity for OER, mainly attributed to the introduction of rich iron or nickel vacancies in NiFe LDHs nanosheets, which efficiently tune the surface electronic structure increasing the adsorbing capacity of OER intermediates. Density functional theory (DFT) computational results also further indicate that the OER catalytic performance of NiFe LDHs can be pronouncedly improved by introducing Fe or Ni vacancies.

Expansion of a Population of Large Monocytes (Atypical Monocytes) in Peripheral Blood of Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Diseases.

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is closely associated with airway inflammation including monocytes, lymphocytes, and neutrophils. Monocytes play an essential role in the pathogenesis of chronic obstructive pulmonary disease (COPD). To elucidate the association of circulating monocyte alteration with AECOPD, we analyzed monocyte subpopulation in the peripheral blood of 16 healthy volunteers and 22 AECOPD patients at the stages of admission and remission after clinical therapy. We found a dramatic increase of a previously unreported population of large size circulating atypical monocytes (A Mo) in AECOPD patients, characterized by higher forward scatter and lower side scatter values than the typical monocytes (T Mo) which were observed predominantly in healthy individuals. Further analysis showed that A Mo expressed higher levels of CD16, intercellular adhesion molecule 1 (ICAM-1), and chemotactic protein-1 receptor-2 (CCR2) than T Mo. In contrast, the expression of class II antigen (HLA-DR) by A Mo was lower than T Mo. More importantly, we observed that the percentage of circulating A Mo among total monocytes correlated with the length of hospital stay (time to remission) and disease duration. The data suggest that circulating A Mo might have the potential to serve as a biomarker in the diagnosis and prognosis of AECOPD.

Prognostic value of metformin for non-small cell lung cancer patients with diabetes.

BACKGROUND: The anti-cancer role of metformin has been reported in many different kinds of solid tumors, but how it affects non-small cell lung cancer (NSCLC) is currently elusive. The aim of this study was to investigate the influence of metformin treatment on diabetic NSCLC. METHODS: Two hundred fifty-five patients of diabetic NSCLC receiving therapy in our hospital from 2014 to 2016 were enrolled in our study. The information on clinical diagnosis, pathology, and prognosis as well as the influence of metformin in diabetic NSCLC were collected and assessed. Univariate and multivariate analytical techniques were applied to explore how metformin affect the survival of NSCLC. RESULTS: One hundred fifty of the 255 diabetic NSCLC patients took metformin. The median overall survival time (OST) and disease-free survival time (DFST) were significantly prolonged with metformin treatment compared to without metformin treatment (OST 25.0 vs 11.5 months, p = 0.005; DFST 15.6 vs 8.5 months, p = 0.010). Multivariate analysis indicated that metformin treatment could be used to predict the long-term outcome of diabetic NSCLC independently (HR = 0.588, 95% CI 0.466-0.895, p = 0.035). CONCLUSION: Our study revealed that the metformin could help in improving the final outcome of NSCLC patients with diabetes in the long term and thus could be applied to treat NSCLC.

Preferential Cation Vacancies in Perovskite Hydroxide for the Oxygen Evolution Reaction.

The oxygen evolution reaction (OER) is an ideal model to study the relationship between the activity and the surface properties of catalysts. Defect engineering has been extensively developed to tune the electrocatalytic activity for OER. Compared to the anion vacancies in metal oxides, cation vacancies are more challenging to selectively generate, and the insight into the structure and activity of cation vacancies-rich catalysts are lacked. Herein, using SnCoFe perovskite hydroxide as a precursor, abundant Sn vacancies on the surface were preferentially produced by Ar plasma. Sn vacancies could be preferentially produced as confirmed by the X-ray absorption spectra, probably owing to the lower lattice energy and weaker chemical bonds of Sn(OH)4 . The Sn vacancies promoted the exposure of active CoFe sites, resulting in an amorphous surface layer, modulated the conductivity, and thus enhanced the OER performance.

Exploring the Performance Improvement of the Oxygen Evolution Reaction in a Stable Bimetal-Organic Framework System.

Despite wide applications of bimetallic electrocatalysis in oxygen evolution reaction (OER) owing to their superior performance, the origin of the improved performance remains elusive. The underlying mechanism was explored by designing and synthesizing a series of stable metal-organic frameworks (MOFs: NNU-21-24) based on trinuclear metal carboxylate clusters and tridentate carboxylate ligands. Among the examined stable MOFs, NNU-23 exhibits the best OER performance; particularly, compared with monometallic MOFs, all the bimetallic MOFs display improved OER activity. DFT calculations and experimental results demonstrate that introduction of the second metal atom can improve the activity of the original atom. The proposed model of bimetallic electrocatalysts affecting their OER performance can facilitate design of efficient bimetallic catalysts for energy storage and conversion, and investigation of the related catalytic mechanisms.

Determination of norfloxacin in food by an enhanced spectrofluorimetric method.

BACKGROUND: Using a norfloxacin (NFLX)-Nd3+ -cetyltrimethylammonium bromide (CTAB) system for the detection of NFLX, a simple and sensitive method based on fluorescence enhancement was developed. RESULTS: In pH 7.0 buffer solution, NFLX reacted with Nd3+ to form a complex, which resulted in fluorescence enhancement of NFLX, and the maximum emission peak shifted from 415 nm for NFLX to 450 nm for NFLX-Nd3+ . Moreover, the fluorescence intensity increased further when the surfactant CTAB was added to NFLX-Nd3+ . Under the optimum conditions, the fluorescence intensity of the NFLX-Nd3+ -CTAB system was linearly correlated with the NFLX concentration in the range 0.038-10 µmol L-1 , with a correlation coefficient (R2 ) of 0.9997. The detection limit (3σ/k) was 0.021 µmol L-1 , indicating that this method can be applied to detect trace NFLX levels. The mechanism of fluorescence enhancement is discussed. The method was used to detect NFLX in fish and chicken samples with satisfactory results. CONCLUSION: The present results indicate that this method has the potential for fast and real-time determination of NFLX in food samples © 2016 Society of Chemical Industry.

Enantioselective Friedel-Crafts Alkylation Reactions of 3-Substituted Indoles with Electron-Deficient Alkenes.

Highly enantioselective Friedel-Crafts C2-alkylation reactions of 3-substituted indoles with α,ß-unsaturated esters and nitroalkenes were developed using chiral Lewis acids as catalysts, which afforded chiral indole derivatives bearing C2-benzylic stereogenic centers in good to excellent yields (up to 99%) and enantioselectivities (up to 96% ee).

Lysosome-associated protein transmembrane-4ß-35 is a novel independent prognostic factor in small cell lung cancer.

The lysosome-associated protein transmembrane-4ß-35 (LAPTM4B-35) protein has been indicated to be involved in solid tumors, while its role in small cell lung cancer (SCLC) remains unknown. The aim of this study is to investigate the LAPTM4B-35 protein expression and its clinical and prognostic role in SCLC patients. A total of 88 SCLC patients who underwent radical surgery between 2002 and 2010 were enrolled in the study. The level of messenger RNA (mRNA) and protein was detected from the fresh paired tumor specimens and adjacent normal tissues. The clinicopathological and survival data were collected. And the relationship between LAPTM4B-35 and clinicopathological features was analyzed. The prognostic value of LAPTM4B-35 for SCLC was investigated by univariate and multivariate analyses. The LAPTM4B-35 was overexpressed significantly in SCLC cancer tissues. The elevated protein expression was correlated strongly with clinical stage (p = 0.012) and tumor recurrence (p = 0.023). The 5-year overall survival and disease-free survival (DFS) were significantly worse in the patients with high LAPTM4B-35 level. Multivariate Cox analysis indicated that high LAPTM4B-35 expression was an independent prognostic factor for overall survival (OS) and DFS (p = 0.017 vs p = 0.011). LAPTM4B-35 overexpression was an independent factor in SCLC prognosis, which may be considered a potential useful marker in defining the SCLC prognosis.

Study on interactions of aminoglycoside antibiotics with calf thymus DNA and determination of calf thymus DNA via the resonance Rayleigh scattering technique.

A simple and sensitive resonance Rayleigh scattering (RRS) spectra method was developed for the determination of calf thymus DNA (ctDNA). The enhanced RRS signals were based on the interactions between ctDNA and aminoglycoside antibiotics (AGs) including kanamycin (KANA), tobramycin (TOB), gentamicin (GEN) and neomycin (NEO) in a weakly acidic medium (pH 3.3-5.7). Parameters influencing the method were investigated. Under optimum conditions, increments in the scattering intensity (∆I) were directly proportional to the concentration of ctDNA over certain ranges. The detection limit ranged from 12.2 to 16.9 ng/mL. Spectroscopic methods, including RRS spectra, absorption spectra and circular dichroism (CD) spectroscopy, coupled with thermo-denaturation experiments were used to study the interactions, indicating that the interaction between AGs with ctDNA was electrostatic binding mode.

A rapid and sensitive resonance Rayleigh scattering spectra method for the determination of quinolones in human urine and pharmaceutical preparation.

A new method based on resonance Rayleigh scattering (RRS) was proposed for the determination of quinolones (QNS) at the nanogram level. In pH 3.3-4.4 Britton-Robinson buffer medium, quinolones such as ciprofloxacin, pipemidic acid (PIP), lomefloxacin (LOM), norfloxacin (NOR) and sarafloxacin (SAR) were protonated and reacted with methyl orange (MO) to form an ion-pair complex, which then further formed a six-membered ring chelate with Pd(II). As a result, new RRS spectra appeared and the RRS intensities were enhanced greatly. RRS spectral characteristics of the MO-QNS-Pd(II) systems, the optimum conditions for the reaction, and the influencing factors were investigated. Under optimum conditions, the scattering intensity (∆I) increments were directly proportional to the concentration of QNS with in certain ranges. The method had high sensitivity, and the detection limits (3σ) ranged from 6.8 to 12.6 ng/mL. The proposed method had been successfully applied for the determination of QNS in pharmaceutical formulations and human urine samples. In addition, the mechanism of the reaction system was discussed based on IR, absorption and fluorescence spectral studies. The reasons for the enhancement of scattering spectra were discussed in terms of fluorescence-scattering resonance energy transfer, hydrophobicity and molecular size.

Triple-wavelength overlapping resonance Rayleigh scattering method for facile and rapid assay of perfluorooctane sulfonate.

In the present study, a novel triple-wavelength overlapping resonance Rayleigh scattering (TWO-RRS) method had been well established to detect perfluorooctane sulfonate (PFOS). We found that crystal violet (CV) could react with PFOS to form 1:1 ion-association complex by electrostatic attraction and hydrophobic effect over a wide pH range (5.0∼11.0) in less than 60 s. The complexes would further self-aggregated into nanoparticles [CV-PFOS]n. Based on this phenomenon, not only the absorption and Raman spectra were changed but also the resonance Rayleigh scattering (RRS) intensities were significantly enhanced. And three new RRS peaks located at 327, 492, and 654 nm were clearly observed, respectively. At the same time, it was found that both the enhanced single-wavelength resonance Rayleigh scattering (SW-RRS) and TWO-RRS intensities against the concentration of PFOS showed an excellent correlation. The detection limits for the three single peaks were 27.4 nmol L(-1) (13.7 µg L(-1), 327 nm), 27.5 nmol L(-1) (13.8 µg L(-1), 492 nm), and 31.4 nmol L(-1) (15.7 µg L(-1), 654 nm), and for TWO-RRS method was 5.9 nmol L(-1) (3.0 µg L(-1)). Moreover, it could be applied to determine PFOS water samples successfully.