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Lithium-oxygen batteries with ultrahigh energy densities have drawn considerable attention as next-generation energy storage devices. However, their practical applications are challenged by sluggish reaction kinetics aimed at the formation/decomposition of discharge products on battery cathodes. Developing effective catalysts and understanding the fundamental catalytic mechanism are vital to improve the electrochemical performance of lithium-oxygen batteries. Here, uniformly dispersed ruthenium nanoparticles anchored on nitrogen-doped reduced graphene oxide are prepared by using an

Highlights Hard-carbon anode dominated with ultra-micropores ( The ultra-micropores dominated carbon anode displays an enhanced capacity, which originates from the extra sodium-ion storage sites of the designed ultra-micropores. The thick electrode (~ 19 mg cm−2) with a high areal capacity of 6.14 mAh cm−2 displays an ultrahigh cycling stability and an outstanding low-temperature performance. Abstract Pore structure of hard carbon has a fundamental influence on the electrochemical properties in sodium-ion batteries (SIBs). Ultra-micropores (+ but allow the entrance of naked Na+ into the pores, which can reduce the interficial contact between the electrolyte and the inner pores without sacrificing the fast diffusion kinetics. Herein, a molten diffusion–carbonization method is proposed to transform the micropores (> 1 nm) inside carbon into ultra-micropores (−1 at 30 mA g−1 with a high ICE value of ~ 80.6% and most of the capacity (~ 90%) is below 1 V. Moreover, the high-loading electrode (~ 19 mg cm−2) exhibits a good temperature endurance with a high areal capacity of 6.14 mAh cm−2 at 25 °C and 5.32 mAh cm−2 at − 20 °C. Based on the in situ X-ray diffraction and ex situ solid-state nuclear magnetic resonance results, the designed ultra-micropores provide the extra Na+ storage sites, which mainly contributes to the enhanced capacity. This proposed strategy shows a good potential for the development of high-performance SIBs.

ZnO-based catalysts have been widely used in industrial reactions involving syngas conversions. Hydrogen dynamics on the surface of the catalyst is an essential process for understanding the mechan...

Organic anode materials have attracted considerable interest owing to their high tunability by adopting various active functional groups. However, the interaction mechanisms between the alkali metals and the active functional groups in host materials have been rarely studied systematically. Here, a widely used organic semiconductor of perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) was selected as a model system to investigate how alkali metals interact with imide functional groups and induce changes in chemical and electronic structures of PTCDI. The interaction at the alkali/PTCDI interface was probed by in-situ X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), synchrotron-based near edge X-ray absorption fine structure (NEXAFS), and corroborated by density functional theory (DFT) calculations. Our results indicate that the alkali metal replaces the hydrogen atoms in the imide group and interact with the imide nitrogen of PTCDI. Electron transfer induced gap states and downward band-bending like effects are identified on the alkali-deposited PTCDI surface. It was found that Na shows a stronger electron transfer effect than Li. Such a model study of alkali insertion/intercalation in PTCDI gives insights for the exploration of the potential host materials for alkali storage applications.

Nitrogen fixation is a vital process for both nature and industry. Whereas the nitrogenase can reduce nitrogen in ambient environment in nature, the industrialized Haber-Bosch process is a high temperature and high-pressure process. Since the discovery of the first dinitrogen complex in 1965, many dinitrogen complexes are prepared in a homogeneous solution to mimic the nitrogenase enzyme in nature. However, studies of the heterogeneous process on surface are rarely addressed. Moreover, molecular scale characterization for such dinitrogen complex is lacking. Here, we present a simple model system to investigate, at the single-molecule level, the binding of dinitrogen on a surface confined iron phthalocyanine (FePc) monolayer through the combination of in-situ low-temperature scanning tunneling microscopy (LT-STM) and X-ray photoelectron spectroscopy (XPS) measurements. The iron center in FePc molecule deposited on Au(111) and highly oriented pyrolytic graphite (HOPG) surface can adsorb dinitrogen molecule at room temperature and low pressure. A comparative study reveals that the adsorption behaviors of FePc on these two different substrates are identical. Chemical bond is formed between the dinitrogen and the Fe atom in the FePc molecule, which greatly modifies the electronic structure of FePc. The bonding is reversible and can be manipulated by applying bias using a STM tip or by thermal annealing.

This study used hydrogen proton magnetic resonance imaging to detect the changes of white matter and the medial cortex in the prefrontal cortex of patients with type 2 diabetes, analyzed its relationship with cognitive function and blood glucose level, and discussed the recognition of patients with type 2 diabetes from the perspective of brain metabolism. We discuss the neural mechanisms affected by the disorder. The experiment recruited 65 volunteers, including 32 control subjects and 33 patients with type 2 diabetes. All volunteers underwent clinical cognitive function and psychological evaluation, including a simple intelligent mental state examination scale, digital breadth test, Raven intelligence test, Flanker paradigm experiment, connection test, auditory word learning test, depression self-evaluation scale, and anxiety self-rating scale. All subjects underwent multivoxel proton magnetic resonance scanning, and the spectral data were processed and metabolite concentration analysis was completed by Functool software. The detected regions of interest included the bilateral prefrontal white matter and bilateral prefrontal cortex. This study found that the N-acetylaspartate (NAA) and NAA/myo-inositol (MI) of the right prefrontal cortex were reduced, the right prefrontal white matter choline-containing compounds increased, and the MI of the bilateral prefrontal cortex increased in the type 2 diabetes group compared with the control group. The NAA value of the right prefrontal cortex in the type 2 diabetes group was negatively correlated with the glycated hemoglobin concentration. The study found that the right prefrontal cortex NAA value of patients with type 2 diabetes was negatively correlated with the glycated hemoglobin concentration, reflecting that recent blood glucose levels can affect the changes of brain metabolites, and reasonable control of blood glucose can effectively delay brain neurons caused by diabetes.

Metal-organic frameworks (MOFs) have been widely employed as the precursors to obtain functional carbon with tuneable composition and structure. However, the design of 2D carbon nanostructures directly from two-dimensional (2D) nonlayered MOFs is still very scarce, which is mainly hindered by the synthesis of 2D nonlayered MOFs. Herein, 2D nonlayered NH2-MIL-53 (Al) is synthesized via inorganic anion modulation for 2D S, N, O-rich hard carbon nanosheets (SNO-HCN) precursor. Due to the introduction of S-doping, more open edge sites generate, which accordingly promote the formation of pyridinic N and C=O carbonyl groups. When adopted as the anode for the sodium ion batteries, the SNO-HCN electrode delivers high reversible capacity of 522 mAh g−1 and 185 mAh g−1 at 50 mA g−1 and 15000 mA g−1, respectively. The enlarged interlayer spacing, unique 2D structure, heteroatom-rich active sites, and high surface area lead to the improved electrochemical performance. Furthermore, the galvanostatic intermittent titration technique (GITT) test indicates the superior electrochemical kinetics of the SNO-HCN electrode and the quantitative analysis reveals the capacitance contribution dominates during sodium-ion storage process. This represents an universal approach for the preparation of various 2D carbon nanomaterials derived from 2D nonlayered MOFs.

Superoxide (O2-) species play a crucial role in determining the charge kinetics for aprotic lithium-oxygen (Li-O2) batteries. However, the growth of O2--rich lithium peroxide (Li2O2) is challenging since O2- is thermodynamically unfavorable and unstable in an O2 atmosphere. Herein, we reported the synthesis of defective Li2O2 with tunable O2- via K+ doping. The K+ dopants can successfully stabilize O2- species and induce the coordination of Li+ with O2-, leading to increased Li vacancies. Compared to the pristine Li2O2, the as-prepared defective Li2O2 can be charged at a lower overpotential in Li-O2 batteries, which is ascribed to further increased Li vacancies contributed by the depotassiation process at the onset of the charge process. Our findings suggest a new strategy to better control O2- species in Li2O2 by K+ dopants and provide insights into the K+ effects on charge mechanism in Li-O2 batteries.

Practical applications of two-dimensional (2D) black phosphorus (BP) are limited by its fast degradation under ambient conditions, for which many different mechanisms have been proposed; however, an atomic level understanding of the degradation process is still hindered by the absence of bottom-up methods for the growth of large-scale few-layer black phosphorus. Recent experimental success in the fabrication of single-layer blue phosphorus provides a model system to probe the oxidation mechanism of two-dimensional (2D) phosphorene down to single-layer thicknesses. Here, we report an atomic-scale investigation of the interaction between molecular oxygen and blue phosphorus. The atomic structure of blue phosphorus and the local binding sites of oxygen have been precisely identified using qPlus-based noncontact atomic force microscopy. A combination of low-temperature scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements reveal a thermally reversible oxidation process of blue phosphorus in a pure oxygen atmosphere. Our study clearly demonstrates the essential role of oxygen in the initial oxidation process, and it sheds further light on the fundamental pathways of the degradation mechanism.

Two-dimensional (2D) nanomaterials , including metal-free (graphene, carbon nitride , and black phosphorus et al.) and transition metal-based materials (dichalcogenides, oxides, hydroxides, phosphides, and MXenes et al.), have emerged as promising candidates for electrocatalysis due to their unique physical, chemical, and electronic properties. Specifically, 2D materials with ultra-thin thickness usually possess more vacancy-type defects and exposed edges than bulk materials, resulting in different electronic characteristics relative to those of bulk materials and leading to changes in the reactant absorption energy on catalysts. Introducing heteroatom dopants can further alter the charge distribution in 2D materials, thereby facilitating the formation of new defects and catalytic active-sites to improve the electrocatalytic performance. This review highlights recent defect chemistry advances and developments in 2D materials for electrocatalysis. We discuss various defects in 2D materials, such as edge defects, topological defects and vacancy defects so on, and the effects of defects on electrocatalytic performance. Defect engineering and rational design strategies for controlling defects on 2D materials will also be systematically discussed. Finally, various advanced characterization technologies to reveal different types of defects will be discussed.

Plant phenology, the annually recurring sequence of plant developmental stages, is important for plant functioning and ecosystem services and their biophysical and biogeochemical feedbacks to the climate system. Plant phenology depends on temperature, and the current rapid climate change has revived interest in understanding and modeling the responses of plant phenology to the warming trend and the consequences thereof for ecosystems. Here, we review recent progresses in plant phenology and its interactions with climate change. Focusing on the start (leaf unfolding) and end (leaf coloring) of plant growing seasons, we show that the recent rapid expansion in ground- and remote sensing- based phenology data acquisition has been highly beneficial and has supported major advances in plant phenology research. Studies using multiple data sources and methods generally agree on the trends of advanced leaf unfolding and delayed leaf coloring due to climate change, yet these trends appear to have decelerated or even reversed in recent years. Our understanding of the mechanisms underlying the plant phenology responses to climate warming is still limited. The interactions between multiple drivers complicate the modeling and prediction of plant phenology changes. Furthermore, changes in plant phenology have important implications for ecosystem carbon cycles and ecosystem feedbacks to climate, yet the quantification of such impacts remains challenging. We suggest that future studies should primarily focus on using new observation tools to improve the understanding of tropical plant phenology, on improving process-based phenology modeling, and on the scaling of phenology from species to landscape-level.

As a pore-forming toxin, activation, oligomerization and pore-formation were both required for the mode of action of Cry toxins. Previous results revealed that the helices α4–α5 of Domain I were involved in the oligomerization of Cry2Ab, however, the key residues for Cry2Ab aggregation remained ambiguous. In present studies, we built 20 Cry2Ab alanine mutants site-directed in the helices α4–α5 of Domain I and demonstrated that mutants N151A, T152A, F157A, L183A, L185A and I188A could reduce the assembly of the 250 kDa oligomers, suggesting that these mutation residues might be essential for Cry2Ab oligomerization. As expected, all of these variants showed lower insecticidal activity against P. xylostella. Furthermore, we found that the pore-forming activities of these mutants also decreased when compared to wild-type Cry2Ab. Taken together, our data identified key residues for Cry2Ab oligomerization and emphasized that oligomerization was closely related to the insecticidal activity and pore-forming activity of Cry2Ab. Supplementary Information The online version contains supplementary material available at 10.1186/s13568-021-01270-0.

Photocatalytic hydrogen peroxide (H2O2) generation represents a promising approach for artificial photosynthesis. However, the sluggish half-reaction of water oxidation significantly limits the efficiency of H2O2 generation. Here, a benzylamine oxidation with more favorable thermodynamics is employed as the half-reaction to couple with H2O2 generation in water by using defective zirconium trisulfide (ZrS3) nanobelts as a photocatalyst. The ZrS3 nanobelts with disulfide (S22−) and sulfide anion (S2−) vacancies exhibit an excellent photocatalytic performance for H2O2 generation and simultaneous oxidation of benzylamine to benzonitrile with a high selectivity of >99%. More importantly, the S22− and S2− vacancies can be separately introduced into ZrS3 nanobelts in a controlled manner. The S22− vacancies are further revealed to facilitate the separation of photogenerated charge carriers. The S2− vacancies can significantly improve the electron conduction, hole extraction, and kinetics of benzylamine oxidation. As a result, the use of defective ZrS3 nanobelts yields a high production rate of 78.1 ± 1.5 and 32.0 ± 1.2 μmol h−1 for H2O2 and benzonitrile, respectively, under a simulated sunlight irradiation.

S. aureus resistant to methicillin (MRSA) is one of the most-concerned multidrug resistant bacteria, due to its role in life-threatening infections. There is an urgent need to develop new antibiotics against MRSA. In this study, we firstly compiled a data set of 2,3-diaminoquinoxalines by chemical synthesis and antibacterial screening against S. aureus, and then performed cheminformatics modeling and virtual screening. The compound with the Specs ID of AG-205/33156020 was discovered as a new antibacterial agent, and was further identified as a Gyrase B (GyrB) inhibitor. In light of the common features, we hypothesized that the 6c as the representative of 2,3-diaminoquinoxalines also inhibited GyrB and eventually proved it. Via molecular docking and molecular dynamics simulations, we identified binding modes of AG-205/33156020 and 6c to the ATPase domain of GyrB. Importantly, these GyrB inhibitors inhibited the MRSA strains and showed selectivity to HepG2 and HUVEC. Taken together, this research work provides an effective ligand-based computational workflow for scaffold hopping in anti-MRSA drug discovery, and discovers two new GyrB inhibitors that are worthy of further development.

The growth of entirely synthetic two-dimensional (2D) materials could further expand the library of naturally occurring layered solids and provide opportunities to design materials with finely tunable properties. Among them, the synthesis of elemental 2D materials is of particular interest as they represent the chemically simplest case and serve as a model system for exploring the on-surface synthesis mechanism. Here, a pure atomically thin blue phosphorus (BlueP) monolayer is synthesized

Background/Aims: Evidence from our and other groups has demonstrated that zinc transporter 7 in SLC30 family (ZnT7) inhibited epithelial-to-mesenchymal transition (EMT) and apoptosis in rat peritoneal mesothelial cells (RPMCs) under high glucose (HG) concentration. In the present study, we investigated the effect of ZnT7 on EMT of renal tubular epithelial cells (RTECs) in an in vitro model of diabetic nephropathy (DN). Methods: A dual-fluorescent staining protocol was used for detection of ZnT7 in a normal rat kidney tubular epithelial cell line (NRK-52E cells). EMT was induced with HG (30 mM). NRK-52E cells were transfected with plasmids codifying for hZnT7-EGFP and interfering RNA for determination of the effect of ZnT7 over-expression and silencing, respectively. Expression of ZnT7, activation of the MAPK/ERK and TGF-β/Smad pathways were analyzed with by means of Western blot. Results: ZnT7 was localized in the perinuclear region and Golgi apparatus. In HG-induced EMT of NRK-52E cells, ZnT7 was up-regulated. Over-expression of ZnT7 led to inhibition of HG-induced EMT, while knock-down of ZnT7 increased EMT. Furthermore, knock-down of ZnT7 and increased HG-induced EMT was accompanied by activation of the MAPK/ERK and TGF-β/Smad pathways. Conclusion: The present study provides evidence that ZnT7 has a protective effect over EMT of RTECs in DN and suggests that the inhibition of HG-induced EMT may be achieved through the MAPK/ERK and TGF-β/Smad pathways. Thereby, ZnT7 could be a potential target for translation medicine and prevention program in DN.

(±)-7-O-galloyltricetiflavan (1a) was synthesized successfully in five steps from the commercially available trihydroxyacetophenone (2) and trimethoxybenzoyl chloride (3). The flavone 4a was prepared in a one-pot reaction and it gave hex-O-methylflavan 6 followed by acylation and reduction. However, the demethylation of flavan 6, 5-O-acetylflavan 10 and 5-O-phenylacetylflavan 11 by BBr3 gave all the hydrolyzed fragments 7 and 8 as the major products. By contrast, in the same condition, hept-O-methylflavan 9 could provide the desired product (±)-7-O-galloyltricetiflavan (1a) in 91% yield. The additional 5-O-B-Br2 complex may stabilize the ester bond during the demethylation process.

Aberrant Wnt signaling has been implicated in a variety of disease. Inhibition of the Wnt pathway is an attractive approach for developing new therapeutics for the treatment of various types of fibrosis and cancers. We have discovered the phthalimide-phenylpyridine conjugate as a novel hit compound for the Wnt pathway inhibitors from cellular screening. The structure-activity relationship of these compounds suggested both of the substituent group on the phthalimide fragment and the structure of the linker were critical to the inhibitory activity. The most potent compound was about 10-folds more potent than the hit compound, with IC50 value of 0.28 ± 0.01 µM.

Lepidopteran midgut aminopeptidases N (APNs) are widely studied for their potential roles as one of the receptors for Bacillus thuringiensis (Bt) crystal toxins. In the present study, a loss of function analyses by RNAi (RNA interference) silencing of the Plutella xylostella APN5 (PxAPN5), a binding protein of Bt crystal toxin Cry2Ab, were performed. The knocking down of PxAPN5 in P. xylostella larvae greatly reduced their susceptibility to Cry2Ab and led to a decrease of Cry2Ab binding to P. xylostella midgut. Four truncated fragments of PxAPN5 were further constructed and expressed in Escherichia coli (E.coli) to find the binding region of PxAPN5 to Cry2Ab. The ligand blot result indicated that D1 domain (residues 1-262) and D3 domain (residues 510-620) of PxAPN5 could specially bind to Cry2Ab.

Two conformationally restricted salinomycin derivatives by tethering the hydroxyl groups at C1 and C20 with different chain length were designed and synthesized. The cyclic derivatives showed better biological activities than C1/C20 modified derivatives, indicating the importance of the compact conformation for the ion binding capacity. In addition, the length of the connective chain plays critical role in the biological activities, thus cyclic the derivative 7 preserved some pharmacological activity but derivative 5 with two carbon atom shorter chain showed significantly reduced activity. The conformations of the two cyclic salinomycin derivatives were analyzed by ROESY spectrum in DMSO-d6, indicating derivative 7 may adopt more appropriate conformations for the coordinate with alkali metal ion than derivative 5, which has a closer distance between H3 and H25.

Markedly minimizing the platinum (Pt) loading and increasing its mass activity are significant to drive down the cost of H2 production from water splitting. Herein, a novel electrocatalyst, Pt nanoparticles (NPs) anchored on Ni/nitrogen-doped graphene nanotubes (Pt/Ni@NGNTs), was designed and its exceptional catalytic performance towards hydrogen evolution reaction was demonstrated. Ni@NGNTs itself showed poor catalytic activity. Unexpectedly, when employed as a support, it increased the mass activity of the Pt metal by 30.1 times in an acidic electrolyte and 15.3 times in an alkaline electrolyte relative to that of commercial 20 wt% Pt/C. Moreover, the durability of Pt/Ni@NGNTs reached up to 50 h. Impressively, Pt NPs preferentially distributed around the protective graphene shells of the enclosed metal Ni, due to the enriched electron density and structural defects induced by Ni and N dopants. The electronic interactions between Pt and Ni@NGNTs tuned the electronic properties and greatly boosted catalytic performances of the anchored Pt NPs. The present catalyst shows significant potential for the synthesis of low cost, high performance Pt-based catalysts.

Bacillus thuringiensis insecticidal proteins (Bt toxins) have been widely used in crops for agricultural pest management and to reduce the use of chemical insecticides. Here, we have engineered Bt toxin Cry2Ab30 and bioconjugated it with 4&rdquo, O-succinyl avermectin (AVM) to synthesize Cry2Ab&ndash, AVM bioconjugate. It was found that Cry2Ab&ndash, AVM showed higher insecticidal activity against Plutella xylostella, up to 154.4 times compared to Cry2Ab30. The binding results showed that Cry2Ab&ndash, AVM binds to the cadherin-like binding protein fragments, the 10th and 11th cadherin repeat domains in the P. xylostella cadherin (PxCR10&ndash, 11), with a much higher affinity (dissociation equilibrium constant KD = 3.44 nM) than Cry2Ab30 (KD = 28.7 nM). Molecular docking suggested that the macrolide lactone group of Cry2Ab&ndash, AVM ligand docking into the PxCR10&ndash, 11 is a potential mechanism to enhance the binding affinity of Cry2Ab&ndash, AVM to PxCR10&ndash, 11. These findings offer scope for the engineering of Bt toxins by bioconjugation for improved pest management.

A microwave-assisted N- fluorobenzenesulfonimide (NFSI)/Lewis acid-catalyzed Beckmann rearrangement was developed. The remarkable promotion to the electrophilicity of NFSI by Lewis acids was illustrated utilizing a series of readily available oxime substrates. The action model between NFSI and Lewis acids was probed by control experiments and theoretical calculations.

A SPEEK/PW 11 V/rGO hybrid film was prepared by a simple method through sulfonated polyether ether ketone (SPEEK), tungstovanadophosphoric acid (H 4 PW 11 VO 40 , abbreviated as PW 11 V) and reduced graphene oxide (rGO) in this work. The results indicate that the Keggin framework of PW 11 VO 40 4 − anion still remain in the hybrid film and confirm the homogeneous dispersion of PW 11 V on the surface of graphene sheet, which results in a better stability of PW 11 V. The electrochemical impedance spectroscopy shows that this film exhibits high proton conductivity of 2.22 × 10 − 2 S cm − 1 at 17 °C and 6.43 × 10 − 2 S cm − 1 at 65 °C (65% relative humidity). Its activation energy value for proton conduction is 18.9 kJ mol − 1 , suggesting that the conduction mechanism for this film is a mix of Vehicle mechanism and Grotthuss mechanism. It is an alternative film material which may be applied in the field of fuel cells.

Organic semiconductor-based electrode materials are promising candidates for energy storage devices due to their high capacity, excellent flexibility, low cost and resource sustainability. The alkali metal storage mechanisms on various active functional groups of the organic materials, however, are still not clear at the molecular scale. It is essential to conduct systematic mechanism studies for the alkali storage behaviors in organic electrode materials. Here, the chemical and electronic structure evolutions upon the deposition of lithium (Li) and sodium (Na) on a model organic semiconductor electrode material of perylene-3,4,9,10-tetracarboxylicdianhydride (PTCDA), have been investigated by in-situ x-ray photoemission spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), near edge x-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory (DFT) calculations. It reveals that Li/Na can react with the carbonyl oxygen and increase the electron density within the PTCDA perylene. Moreover, the band-bending like features are observed on PTCDA film upon Li/Na interaction. Our experimental results and theoretical calculations indicate that reactions on carbonyl groups and charge redistribution are crucial for the Li/Na storage process, which shed light on comprehensive insights for the Li/Na storage behaviors on organic semiconductor-based electrode materials. Ministry of Education (MOE) Authors acknowledge the financial support from Singapore MOE grant R143-000-A29-112 and Academic Research Fund Tier 1 (RG104/ 18), as well as the computing resources from National Supercomputing Centre Singapore.

Lithium-rich layered oxides, xLi2MnO3·(1−x)LiMO2(M = Ni, Mn, Co), have been under intense investigation as high-performance cathode materials for lithium ion batteries due to their high discharge capacity, low cost and environmental benignity. Unfortunately, the commercialized application of these cathode materials have so far been hindered by their severe capacity and voltage fading during high voltage cycling (>4.5 V vs. Li/Li+). In an attempt to overcome these problems, herein, highly crystalline Al2O3 layer from the hydrolysis of aluminum isopropoxide are coated on 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2 with controlling the growth of Al2O3 crystals. The coin cell with bare cathode material delivers a high discharge capacity over 268.2 mAh g−1 between 2.0 V and 4.8 V, while the Al2O3 coated cathode material shows the excellent cycling stability corresponding to 98% capacity retention after 100 cycles at 1C. More importantly, the highly crystalline Al2O3 coated cathode materials exhibit a significantly lower discharge voltage decay compared to the bare cathode materials, which could be ascribed to the suppression of the layered-to-spinel transformation by compact and highly crystalline Al2O3 layer. The results here will shed light on developing cathode materials with special structures and superior electrochemical properties for high-performance lithium ion batteries.

Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two recently discovered processes in the nitrogen cycle that are catalysed by anammox bacteria and n-damo bacteria, respectively. Here, the depth-specific distribution and importance of anammox bacteria and n-damo bacteria were studied in an urban wetland, Xixi Wetland, Zhejiang Province (China). Anammox bacteria related to Candidatus Brocadia, Candidatus Kuenenia and Candidatus Anammoxoglobus, and n-damo bacteria related to “Candidatus Methylomirabilis oxyfera” were present in the collected soil samples. The abundance of anammox bacteria (2.6–8.6 × 106 copies g−1 dry soil) in the shallow soils (0–10 cm and 20–30 cm) was higher than that (2.5–9.8 × 105 copies g−1 dry soil) in the deep soils, whereas the abundance of n-damo bacteria (0.6–1.3 × 107 copies g−1 dry soil) in the deep soils (50–60 cm and 90–100 cm) was higher than that (3.4–4.5 × 106 copies g−1 dry soil) in the shallow soils. Anammox activity was detected at all depths, and higher potential rates (12.1–21.4 nmol N2 g−1 dry soil d−1) were observed at depths of 0–10 cm and 20–30 cm compared with the rates (3.5–8.7 nmol N2 g−1 dry soil d−1) measured at depths of 50–60 and 90–100 cm. In contrast, n-damo was mainly occurred at depths of 50–60 cm and 90–100 cm with potential rates of 0.7–5.0 nmol CO2 g−1 dry soil d−1. This study suggested the niche segregation of the anammox bacteria and n-damo bacteria in wetland soils, with anammox bacteria being active primarily in deep soils and n-damo bacteria being active primarily in shallow soils.

Cry2Ab, a pore-forming toxin derived from Bacillus thuringiensis, is widely used as a bio-insecticide to control lepidopteran pests around the world. A previous study revealed that proteolytic activation of Cry2Ab by Plutella xylostella midgut juice was essential for its insecticidal activity against P. xylostella, although the exact molecular mechanism remained unknown. Here, we demonstrated for the first time that proteolysis of Cry2Ab uncovered an active region (the helices α4 and α5 in Domain I), which was required for the mode of action of Cry2Ab. Either the masking or the removal of helices α4 and α5 mediated the pesticidal activity of Cry2Ab. The exposure of helices α4 and α5 did not facilitate the binding of Cry2Ab to P. xylostella midgut receptors but did induce Cry2Ab monomer to aggregate and assemble a 250-kDa prepore oligomer. Site-directed mutagenesis assay was performed to generate Cry2Ab mutants site directed on the helices α4 and α5, and bioassays suggested that some Cry2Ab variants that could not form oligomers had significantly lowered their toxicities against P. xylostella. Taken together, our data highlight the importance of helices α4 and α5 in the mode of action of Cry2Ab and could lead to more detailed studies on the insecticidal activity of Cry2Ab.

We present a method to fabricate superhydrophobic surfaces on copper substrate using reciprocating type high speed wire cut electrical discharge machining (HS-WEDM) and self-assembly technology. Herein, single factor experiment was used to investigate the influence of several major parameters of the wire electrical discharge machining processing, such as pulse width, pulse gap (pulse interval) and power tube, on the contact angle of resulting surface. Results show that a composite structure, composed of craters and projections, is fabricated on the copper surface, which is the key reason of superhydrophobicity. With the change of pulse width, pulse interval, and the number of the power tube, the hydrophobic properties of resulting copper surface was changed. This paper provided the theoretical support for industrialized fabrications of super-hydrophobic brass surface.

Acrylamide, a proven rodent carcinogen, is present in carbohydrate-rich food heated at high temperatures. It can be metabolized into glycidamide mainly by cytochrome P450 2E1 (CYP2E1). The fact that acrylamide is a potential carcinogen to human-beings draws public attention recently. This study aimed to elucidate the effect of acrylamide at low doses on proliferation of HepG2 cells, and to test whether the two well-studied chemopreventive agents, curcumin and (−)-epigallocatechin-3-gallate (EGCG), would have antagonistic effects against acrylamide. The results showed that lower concentration of acrylamide (⩽100 μM) significantly increased the proliferation of HepG2 cells, but not of the other cancer cells (MDA-231, HeLa, A549, and PC-3). Only in HepG2 cells, low concentration of acrylamide was able to induce CYP2E1 expression significantly. Knockdown of CYP2E1 restrained acrylamide to increase viability of HepG2 cells. In addition, acrylamide raised expression of epidermal growth factor receptor (EGFR), cyclin D1 and nuclear factor-κB (NF-κB), which contributed to cell proliferation. Both curcumin and EGCG effectively reduced acrylamide-induced proliferation, as well as protein expression of CYP2E1, EGFR, cyclin D1 and NF-κB. All these results suggest that low concentration of acrylamide may contribute to progression of hepatocellular carcinoma (HCC). Curcumin or EGCG could prevent acrylamide triggering this effect.

The process of nitrite-dependent anaerobic methane oxidation (n-damo) was recently discovered and shown to be mediated by "Candidatus Methylomirabilis oxyfera" (M. oxyfera). Here, evidence for n-damo in three different freshwater wetlands located in southeastern China was obtained using stable isotope measurements, quantitative PCR assays, and 16S rRNA and particulate methane monooxygenase gene clone library analyses. Stable isotope experiments confirmed the occurrence of n-damo in the examined wetlands, and the potential n-damo rates ranged from 0.31 to 5.43 nmol CO2 per gram of dry soil per day at different depths of soil cores. A combined analysis of 16S rRNA and particulate methane monooxygenase genes demonstrated that M. oxyfera-like bacteria were mainly present in the deep soil with a maximum abundance of 3.2 × 10(7) gene copies per gram of dry soil. It is estimated that ∼0.51 g of CH4 m(-2) per year could be linked to the n-damo process in the examined wetlands based on the measured potential n-damo rates. This study presents previously unidentified confirmation that the n-damo process is a previously overlooked microbial methane sink in wetlands, and n-damo has the potential to be a globally important methane sink due to increasing nitrogen pollution.

Apoptosis of tubular epithelial cells is a major feature of diabetic kidney disease, and hyperglycemia triggers the generation of free radicals and oxidant stress in tubular cells. Berberine (BBR) is identified as a potential anti-diabetic herbal medicine due to its beneficial effects on insulin sensitivity, glucose metabolism and glycolysis. In this study, the underlying mechanisms involved in the protective effects of BBR on high glucose-induced apoptosis were explored using cultured renal tubular epithelial cells (NRK-52E cells) and human kidney proximal tubular cell line (HK-2 cells). We identified the pivotal role of phosphatidylinositol 3-kinase (PI3K)/Akt in BBR cellular defense mechanisms and revealed the novel effect of BBR on nuclear factor (erythroid-derived 2)-related factor-2 (Nrf2) and heme oxygenase (HO)-1 in NRK-52E and HK-2 cells. BBR attenuated reactive oxygen species production, antioxidant defense (GSH and SOD) and oxidant-sensitive proteins (Nrf2 and HO-1), which also were blocked by LY294002 (an inhibitor of PI3K) in HG-treated NRK-52E and HK-2 cells. Furthermore, BBR improved mitochondrial function by increasing mitochondrial membrane potential. BBR-induced anti-apoptotic function was demonstrated by decreasing apoptotic proteins (cytochrome c, Bax, caspase3 and caspase9). All these findings suggest that BBR exerts the anti-apoptosis effects through activation of PI3K/Akt signal pathways and leads to activation of Nrf2 and induction of Nrf2 target genes, and consequently protecting the renal tubular epithelial cells from HG-induced apoptosis.

A series of covalently linked porphyrin(Por)-anthraquinone(AQ) hybrids Por-C_n-AQ(n=1,4, 10) with flexible different length carbon chains were synthesized and their intramolecular photoinduced electron transfer(PET) properties were investigated mainly by steady-state fluorescence and decayed luminescence spectra.We studied the PET mechanism using density functional theory(DFT).We found that PET occurs from the porphyrin moiety to the anthraquinone moiety of these dyads and that the PET efficiency is influenced considerably by the length of the linkage between the two moieties in the hybrids. From both the experimental and theoretical results,we can conclude that the PET of these dyads is seemingly most compatible with a"through-bond"(super-exchange) mechanism.

Evidence has demonstrated that hypoxia may have a central pathogenic mechanism in the development of diabetic nephropathy (DN). Epithelial-to-mesenchymal transition (EMT) of mature tubular epithelial cells in kidney is a contributor to the renal accumulation of matrix protein in DN and is highly associated with the progression of tubulointerstitial fibrosis. Zinc (Zn) has anti-fibrosis effects in liver and lungs. In the present study, we aimed to investigate the effect of Zn on renal tubulointerstitial fibrosis especially under hypoxic conditions and its association with DN. We found that Zn treatment blockaded tubular EMT and attenuated renal tubulointerstitial fibrosis by downregulation of hypoxia-inducible factor alpha (HIF-1α) in the kidneys of diabetic streptozotocin-treated mice. High glucose (HG)/hypoxic conditions stimulated EMT in renal tubular cells as indicated by the significant decrease in epithelial marker E-cadherin and ZO-1 while the increase in mesenchymal markers α-smooth muscle actin (α-SMA). Zn supplement mainly prevented HG/hypoxic-induced HIF-1α accumulation and EMT marker changes. In co-treatment Zn with PI3K/Akt/GSK-3β signaling pathway, inhibitor LY294002 prevented HG/hypoxic-induced HIF-1α increase and EMT changes, suggesting that Zn may mediate HG/hypoxic-induced EMT through PI3K/Akt/GSK-3β pathway. Therefore, we concluded that Zn had an important anti-fibrosis role under HG/hypoxic conditions, and a novel mechanism contributing to Zn protection on renal tubular epithelial cells from HG/hypoxia-induced EMT through activation of PI3K/Akt/GSK-3β signaling pathway, which subsequently leads to the downregulation of the expression of HIF-1α.

Tyrosinase is a key enzyme in post-harvest browning of fruit and vegetable. To control and inhibit its activity is the most effective method for delaying the browning and extend the shelf life. In this paper, the inhibitory kinetics of 4-hydroxy cinnamic acid on mushroom tyrosinase was investigated using the kinetics method of substrate reaction. The results showed that the inhibition of tyrosinase by 4-hydroxy cinnamic acid was a slow, reversible reaction with fractional remaining activity. The microscopic rate constants were determined for the reaction on 4-hydroxy cinnamic acid with tyrosinase. Furthermore, the molecular docking was used to simulate 4-hydroxy cinnamic acid dock with tyrosinase. The results showed that 4-hydroxy cinnamic acid interacted with the enzyme active site mainly through the hydroxy competed with the substrate hydroxy group. The cytotoxicity study of 4-hydroxy cinnamic acid indicated that it had no effects on the proliferation of normal liver cells. Moreover, the results of effects of 4-hydroxy cinnamic acid on the preservation of mushroom showed that it could delay the mushroom browning. These results provide a comprehensive underlying the inhibitory mechanisms of 4-hydroxy cinnamic acid and its delaying post-harvest browning, that is beneficial for the application of this compound.

The ground-state geometries of monolithium porphyrin (LiP) π-radical and its three reduced/oxidized species ([LiP] − , [LiP] 2− , and [LiP] + ) have been calculated with the density functional theory. The results show that LiP, [LiP] − and [LiP] + have planar D 4h structures while the [LiP] 2− dianion has a rectangular distorted D 2h structure due to the ground-state Jahn-Teller effect. LiTPP and LiOEP radicals were also studied to assess the effect of peripheral substitutions. The ground-state LiTPP has a normal porphyrin ring (D 4h effective symmetry), while the ground-state LiOEP has a porphyrin ring with pronounced bond length alternation (C 4h effective symmetry) due to the pseudo-Jahn-Teller (pJT) distortion along an A 2g -like coordinate. The spin densities of LiP, LiTPP, and LiOEP were analyzed, showing evident effects of peripheral substitution. Electronic absorption spectrum of LiP radical was calculated with the time-dependent DFT and was compared with the experimental results of LiTPP.

Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two of the most recent discoveries in the microbial nitrogen cycle. In the present study, we provide direct evidence for the cooccurrence of the anammox and n-damo processes in a flooded paddy field in southeastern China. Stable isotope experiments showed that the potential anammox rates ranged from 5.6 to 22.7 nmol N 2 g −1 (dry weight) day −1 and the potential n-damo rates varied from 0.2 to 2.1 nmol CO 2 g −1 (dry weight) day −1 in different layers of soil cores. Quantitative PCR showed that the abundance of anammox bacteria ranged from 1.0 × 10 5 to 2.0 × 10 6 copies g −1 (dry weight) in different layers of soil cores and the abundance of n-damo bacteria varied from 3.8 × 10 5 to 6.1 × 10 6 copies g −1 (dry weight). Phylogenetic analyses of the recovered 16S rRNA gene sequences showed that anammox bacteria affiliated with “ Candidatus Brocadia” and “ Candidatus Kuenenia” and n-damo bacteria related to “ Candidatus Methylomirabilis oxyfera” were present in the soil cores. It is estimated that a total loss of 50.7 g N m −2 per year could be linked to the anammox process, which is at intermediate levels for the nitrogen flux ranges of aerobic ammonium oxidation and denitrification reported in wetland soils. In addition, it is estimated that a total of 0.14 g CH 4 m −2 per year could be oxidized via the n-damo process, while this rate is at the lower end of the aerobic methane oxidation rates reported in wetland soils.

Conjugation of Bacillus thuringiensis δ-endotoxin (Bt toxin) with other toxins for insect pest control has been proposed as a new efficient strategy with increasing insecticidal toxicity and target range and delay the onset of insect resistance. A modified method was investigated by conjugating Bt toxin with 4"-O-succinoyl abamectin to form a new biocide which was named as BtA. 'Zero-length' cross-linker EDC in combination with NHS activated 4"-O-succinoyl abamectin and extended half-life period of active intermediate for binding to Bt toxin. The dissociation constant for 4"-O-succinoyl abamectin binding to Bt toxin was 6.44 μM by fluorescence quenching analysis. BtA showed a higher insecticidal toxicity against Plutella xylostella, while the relative-toxicity multiple of BtA to Bt toxin was calculated as 5.6. The interaction between Bt toxins with their receptors played a key role in toxicity of Bt toxins. The binding analysis showed the dissociation rate for the binding of BtA to its receptors (7.495 × 10(-3) S(-1)) was twice slower than that of Bt toxin (1.695 × 10(-2) S(-1)). The relative dissociation constant of BtA to Bt toxin was only 29% for the binding to the receptors. These results demonstrated that BtA bound to the receptor in BBMV with significantly higher affinity compared with Bt toxin.

UBE1L, ubiquitin-activating enzyme E1-like, is the activating enzyme of ISG15ylation (ISG15, interferon stimulated gene 15). Loss of UBE1L and activation of epidermal growth factor receptor (EGFR) signaling are common events in lung carcinogenesis. Curcumin, a well-studied chemopreventive agent, is known to down-regulate EGFR. The present study demonstrated that curcumin decreased EGFR expression in human bronchial epithelial (HBE) Beas-2B cells and lung cancer A549 cells. For the first time, UBE1L was found to be induced by curcumin in HBE cells. Interestingly, overexpression of UBE1L reduced EGFR at posttranslational level in HBE cells. UBE1L triggered EGFR membrane internalization and promoted complex formation between ISG15 and EGFR. Curcumin decreased EGFR downstream signaling pAKT and nuclear factor κB (NF-κB). Overexpression or knockdown of UBE1L also resulted in down-regulation or up-regulation of phosphoinositide 3-kinase/AKT/NF-κB correspondently. In human samples, there was an inverse relationship between UBE1L and EGFR/AKT/NF-κB in non-small cell lung cancer tissues and adjacent tissues. These results uncover a novel chemopreventive mechanism of curcumin in inducing UBE1L and down-regulating EGFR signaling in HBE cells.

Objectives To investigate the association of the serum leukotrienes (LT) B4 level with the risk of unstable angina pectoris (UAP) and the arachidonate 5-lipoxygenase activating protein (ALOX5AP) gene SG13S114T/A polymorphism in Chinese Han population of Sunan region. Methods The polymorphism in the ALOX5AP gene SG13S114T/A was genotyped by PCR and restriction fragment length polymorphism analysis, and the serum LTB4 level (M/IQR) was measured by ELISA in 141 UAP patients (UAP group) and 132 subjects without coronary heart disease (control group). Results The serum LTB4 level in UAP group was significantly higher than the one in control group (352.52/255.48 pg/ml vs 200.28/237.10 pg/ml, p Conclusions The serum LTB4 level is significantly higher in UAP patients and has significant correlation with the risk of UAP, but unrelated with ALOX5AP gene SG13S114 polymorphism.

For understanding the effect of environment factors on the removal of chromate by bacterial strains and to provide chromate-removing strains for the bioremediation of environments contaminated by chromate,two Gram-positive bacterial strains designated as Chr-9 and Chr-43 respectively,capable of removing Cr(VI) in LB medium,were isolated from sludge collected from one tannery plant in Binzhou,Shandong,China.Based on 16S rRNA genes and phenotype characteristics,strain Chr-9 and Chr-43 were identified as Rhodococcus and Exiguobacterium strains,respectively.The optimal temperature and pH for Cr(VI)-removal by the two strains were 35 ℃ and pH 7.0,respectively.The removal of Cr(VI) was enhanced by supplementation of 0.1~0.5 mol/L NO3-,SO42-,and Cl-for strain Chr-9 and by supplementation of 0.1~0.2 mol/L NO3-,SO42,and Cl-for strain Chr-43.The growth and Cr(VI)-removal rate of strain Chr-43 were both enhanced by co-cultivation with strain Chr-9.These results indicated that the removal of chromate by bacterial strains could be affected by temperature,pH,negative ions,and other co-cultured microbes.