Positional Thiophene Isomerization: A Geometric Strategy for Precisely Regulating the Electronic State of Covalent Organic Frameworks to Boost Oxygen Reduction.

With the oxygen conversion efficiency of metal-free carbon-based fuel cells dramatically improved, the building blocks of covalent organic frameworks (COFs) raised principal concerns on the catalytic active sites with indistinct electronic states. Herein, to address this issue, we demonstrate COFs for oxygen reduction reaction (ORR) by regulating the edge-hanging thiophene units, and the molecular geometries are further modulated via positional thiophene isomerization strategy, affording isomeric COF-α with 2-substitution and COF-ß with 3-substitution on the frameworks. The electronic states and intermediate adsorption ability are well-regulated through geometric modification, resulting in controllable chemical activity and local density of π-electrons. Notably, the introduction of thiophene units with different substitution positions into a pristine pure carbon-based COF model COF-Ph achieves excellent activity with a half-wave potential of 0.76 V versus the reversible hydrogen electrode, which is higher than most of those metal-free or metal-based electrocatalysts. Utilizing the combination of theoretical prediction and in situ Raman spectra, we show that the isomeric thiophene skeleton (COF-α and COF-ß) can induce the dangling unit activation, accurately identifying the pentacyclic-carbon (thiophene α-position) adjacent to sulfur atom as active sites. The results suggest that the isomeric dangling groups in COFs are suitable for the ORR with promising geometry construction.

Tensile-Strained Holey Pd Metallene toward Efficient and Stable Electrocatalysis.

Noble metal-based metallenes are attracting intensive attention in energy catalysis, but it is still very challenging to precisely control the surface structures of metallenes for higher catalytic properties on account of their intrinsic thermodynamic instability. Herein, the synthesis of tensile-strained holey Pd metallene by oxidative etching is reported using hydrogen peroxide, which exhibits highly enhanced catalytic activity and stability in comparison with normal Pd metallene toward both oxygen reduction reaction and formic acid oxidation. The pre-prepared Pd metallene functions as a catalyst to decompose hydrogen peroxide, and the Pd atoms in amorphous regions of Pd metallene are preferentially removed by the introduced hydrogen peroxide during the etching process. The greatly enhanced ORR activity is mainly determined by the strong electrostatic repulsion between intermediate O* and the dopant O, which balances the adsorption strength of O* on Pd sites, ultimately endowing a weakened adsorption energy of O* on TH-Pd metallene. This work creates a facile and economical strategy to precisely shape metallene-based nanoarchitectures with broad applications for energy systems and sensing devices.

Papaver somniferum and Papaver rhoeas Classification Based on Visible Capsule Images Using a Modified MobileNetV3-Small Network with Transfer Learning.

Traditional identification methods for Papaver somniferum and Papaver rhoeas (PSPR) consume much time and labor, require strict experimental conditions, and usually cause damage to the plant. This work presents a novel method for fast, accurate, and nondestructive identification of PSPR. First, to fill the gap in the PSPR dataset, we construct a PSPR visible capsule image dataset. Second, we propose a modified MobileNetV3-Small network with transfer learning, and we solve the problem of low classification accuracy and slow model convergence due to the small number of PSPR capsule image samples. Experimental results demonstrate that the modified MobileNetV3-Small is effective for fast, accurate, and nondestructive PSPR classification.

Interleukin-35 dampens T helper 22 phenotype shift in CD4+CD25+CD127dim/- regulatory T cells in primary biliary cholangitis.

The phenotype shift in regulatory T cells (Tregs) contributes to immunopathogenesis of autoimmune diseases. The current study was aimed to investigate the regulatory function of interleukin-35 (IL-35) to T helper 22 (Th22) cell phenotype shift in Tregs in primary biliary cholangitis (PBC). Fifty-five PBC patients and twenty-four controls were enrolled. CD4+CD25+CD127dim/- Tregs and Th22 cells were investigated by flow cytometry. Forkhead box P3 (FoxP3) and aryl hydrocarbon receptor (AhR) mRNA levels were assessed by real-time polymerase chain reaction. Plasma IL-10 and IL-22 levels were measured by ELISA. Purified Tregs were stimulated with exogenous IL-35, and were co-cultured with autologous CD4+CD25- T cells. Cellular proliferation and cytokine production was measured. Purified Tregs were also cultured into Th22 condition in the presence or absence of exogenous IL-35, and Th22 phenotype were assessed. PBC patients had lower levels of Treg percentage, FoxP3 mRNA, and plasma IL-10, while had higher levels of Th22 proportion, AhR mRNA, and plasma IL-22. Tregs from PBC patients showed reduced immunosuppressive activity, which presented as increased cellular proliferation, interferon-γ production and decreased IL-35/IL-10 secretion in co-culture system. Tregs shifted into Th22 phenotype in PBC patients with elevated CCR4, CCR6, and CCR10 expression as well as increased IL-22 production. IL-35 not only enhanced inhibitory function of Tregs but also suppressed phenotype shift of Tregs into Th22 phenotype in PBC patients. This process was accompanied by elevation of IL-10 and transforming growth factor-ß1 secretion by Tregs from PBC patients. The present data suggested that reduced IL-35 might be insufficient to maintain Tregs function and phenotype shift from Tregs into Th22 phenotype in PBC patients.

Metal-Free Carbon-Based Covalent Organic Frameworks with Heteroatom-Free Units Boost Efficient Oxygen Reduction.

Accurate identification of carbon-based metal-free electrocatalyst (CMFE) activity and enhancing their catalytic efficiency for O2 conversion is an urgent and challenging task. This study reports a promising strategy to simultaneously develop a series of covalent organic frameworks (COFs) with well-defined heterocyclic-free biphenyl or fluorenyl units. Unlike heteroatom doping, the developed method not only supplies methyl-induced molecular configuration to promote activity, but also provides a direct opportunity to identify heteroatom-free carbon active centers. The introduction of methyl groups (MGs) with reversible valence bonds into a pristine biphenyl-based COF results in an excellent performance with a half-wave potential of 0.74 V versus the reversible hydrogen electrode (RHE), which is among the highest values for CMFE-COFs as oxygen reduction reaction (ORR) electrocatalysts. Combined with in situ Raman spectra and theoretical calculations, the MG-bound skeleton (DAF-COF) is found to produce ortho activation, confirming the ortho carbon (site-5) adjacent to MGs as active centers. This may be attributed to the opening and binding of MGs, which effectively regulate the molecular configuration and charge redistribution, as well as improve charge transfer and reduce the energy barrier. This study provides insight into the design of highly efficient metal-free organic electrocatalysts via the regulation of valence bonds.

Ru-incorporated Co3O4 nanoparticles from self-sacrificial ZIF-67 template as efficient bifunctional electrocatalysts for rechargeable metal-air battery.

Ru-incorporated Co3O4 nanoparticles have been synthesized from self-sacrificial ZIF-67 template and utilized as efficient electrocatalysts towards oxygen reduction and evolution reactions (ORR and OER). Amongst, Ru@Co3O4-1.0 exhibited the optimum electrocatalytic behavior with an ultra-low potential gap (0.84 V) between the OER potential (1.61 V at 10 mA cm-2) and ORR half-wave potential (0.77 V). The zinc-air battery using Ru@Co3O4-1.0 as a cathode presented high specific capacity (788.1 mAh g-1) and power density (101.2 mW cm-2). Meanwhile, this battery possessed relatively lower voltage gap and higher cycling stability compared with the commercial Pt/C-based one. Ruthenium incorporation induced remarkable lattice expansion of Co3O4 and engineered more oxygen vacancies, promoting the lattice oxygen mobility from the subsurface/bulk phase onto surface. All these properties were recognized to be the crucial parameters for electrocatalytic activity improvement. This work provided a facile approach to design highly active metal oxide with broad potentiality for rechargeable metal-air batteries.

OsGF14b is involved in regulating coarse root and fine root biomass partitioning in response to elevated [CO2] in rice.

Elevated [CO2] can increase rice biomass and yield, but the degree of this increase varies substantially among cultivars. Little is known about the gene loci involved in the acclimation and adaptation to elevated [CO2] in rice. Here, we report on a T-DNA insertion mutant in japonica rice exhibiting a significantly enhanced response to elevated [CO2] compared with the wild type (WT). The root biomass response of the mutant was higher than that of the WT, and this manifested in the number of adventitious roots, the average diameter of roots, and total root length. Furthermore, coarse roots (>0.6 mm) and thin lateral roots (<0.2 mm) were more responsive to elevated [CO2] in the mutant. When exposed to lower light intensity, however, the response of the mutant to elevated [CO2] was not superior to that of the WT, indicating that the high response of the mutant under elevated [CO2] was dependent on light intensity. The T-DNA insertion site was located in the promoter region of the OsGF14b gene, and insertion resulted in a significant decrease in OsGF14b expression. Our results indicate that knockout of OsGF14b may improve the response to elevated [CO2] in rice by enhancing carbon allocation to coarse roots and to fine lateral roots.

Annexin A2 degradation contributes to dopaminergic cell apoptosis via regulating p53 in neurodegenerative conditions.

BACKGROUND: P53 overexpression has been shown to involve in mitochondria-mediated dapaminergic neuron cell death in Parkinson's disease. However, the exactly molecular mechanisms responsible for the p53-dependent intrinsic cell death in neurodegenerative conditions remain unclearly. Annexin A2 is a multifunctional protein that negatively regulates p53 expression. The purpose of this study was to explore the mechanism of p53 dependent dopaminergic cell death and implication of Annexin A2 in cellular apoptosis in 1-methyl-4-phenylpyridinium (MPP+)-induced PC12 cells. METHODS: The cell viability of neural PC12 cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltet-razolium bromide assay. Flow cytometry was used to evaluate the apoptosis and mitochondrial transmembrane potential of neural PC12 cells. The expression of p53 and Annexin A2 was analyzed by western blot assay. RESULTS: The present study showed that the exposure of PC12 cells to neurotoxin MPP+ increased the expression levels of p53 and the discharge of mitochondrial transmembrane potential. Notably, Annexin A2 degradation was also observed in this cellular model of Parkinson's disease, in a time and dose-dependent manner. This expressing change of Annexin A2 was in direct proportion to the loss of cell viability of PC12 cells, and this expression pattern was in inverse proportion to p53 levels in this cellular model of Parkinson's disease. CONCLUSION: These results indicated that Annexin A2 degradation plays a crucial role the degeneration of dapaminergic cells of Parkinson's disease, and Annexin A2 downregulation-mediated the cell death is closely associated with mitochondrial dysfunction via p53-dependent pathway; thus provide a novel therapeutic target for Parkinson's disease treatment.

Polyhedral cobalt oxide supported Pt nanoparticles with enhanced performance for toluene catalytic oxidation.

Polyhedral CoOx was synthesized by calcination of Co-based metal-organic framework ZIF-67 and highly dispersed Pt nanoparticles were successfully loaded on CoOx. The catalytic results showed that Ptnano/CoOx had the best activity and stability. As compared with conventional Co3O4, polyhedral CoOx showed more excellent catalytic oxidation performance of toluene, which was related to enhanced oxygen mobility, defective structure and rich active oxygen species provided by Polyhedral CoOx. Moreover, Pt-CoOx metal-support interaction enhanced the dispersion of Pt species and showed more Pt0 ratio. It was reasonable that the gaseous O2 can be activated directly or moved into the catalyst's surface to form oxygen cycle.

Catalytic mechanism and pathways of 1, 2-dichloropropane oxidation over LaMnO3 perovskite: An experimental and DFT study.

The rational comprehension on the catalytic mechanism and pathways of chlorinated volatile organic compounds (CVOCs) oxidation is meaningful for the design of high performance catalytic materials. Herein, we attempted to elucidate the catalytic mechanism and pathways of 1, 2-dichloropropane (1, 2-DCP) oxidation over LaMnO3 perovskite from experimental and theoretical studies. Experimental results indicate that the initial dechlorination of 1, 2-DCP into allyl chloride (AC) can be readily achieved over LaMnO3, while the further decomposition of AC is more vulnerable to be affected by the reaction conditions and strongly dependent on the surface active oxygen species. Density functional theory (DFT) calculation reveals that the heterogeneous conversion of 1, 2-DCP initiates with the chemisorption on the Mn site, followed by the formation of AC via a synergistic mechanism. AC decomposition is considered as the rate-determining step under an inert condition, while the dechlorination of adsorbed 1, 2-DCP dominates the whole reaction under an oxygen atmosphere.

Effects of dynamic pressure on the proliferation and mechanical properties of rabbit adipose mesenchymal stem cells transfected with insulin-like growth factor-1 / 中国组织工程研究

BACKGROUND: Adipose mesenchymal stem cells are currently recognized as excellent seed cells for tissue engineering cartilage. Gene transfection technology can effectively induce them to differentiate into cartilage. The bioreactor is used to simulate the mechanical environment in vivo. It is a new idea for the majority of scholars to explore the construction of tissue engineering cartilage in vitro. OBJECTIVE: To investigate the effects of cyclic dynamic compressive stress combined with insulin-like growth factor-1 gene transfection on the proliferation and elastic modulus of rabbit adipose mesenchymal stem cells implanted in chitosan/gelatin scaffold. METHODS: Rabbit adipose mesenchymal stem cells were transfected with pcDNA3.1-IGF-1 gene mediated by liposome. The stable transfected cell lines were screened by G418. The adipose mesenchymal stem cells transfected with or without insulin-like growth factor-1 gene were inoculated in chitosan/ gelatin scaffold at the density of 5×1010 L-1 for 2 days, and cultured under dynamic pressure (2% at 1 Hz, 4 hours per day) or static culture conditions for 7 days, respectively. The morphological changes of the cell/scaffold complex were observed by scanning electron microscope, Masson trichrome staining and alcian blue staining. The cell proliferation curve was drawn by MTT assay. The cell proliferation efficiency and distribution were evaluated by CM-Dil fluorescence-labeling method, and the content of total glycosaminoglycan was quantitatively determined by DMMB. The differences of type II collagen among different groups were compared with real time PCR. Compressive mechanical properties of the cell/scaffold constructs were assessed using a BioDynamic™ mechanical tester, and the corresponding elastic modulus was calculated. RESULTS AND CONCLUSION: Dynamic pressure combined with insulin-like growth factor-1 transfection could significantly improve the cell proliferation ability of the cell/scaffold complex; the cell distribution was more uniform; glycosaminoglycan and collagen secretion in the cartilage-specific extracellular matrix were increased; the expression levels of type II collagen were up-regulated; and the mechanical properties were significantly improved. The cell proliferation and elastic modulus of insulin-like growth factor-1 group were better than those of single pressure group, but the distribution of cells in scaffolds was more uniform under dynamic pressure. The results indicate that both dynamic pressure and insulin-like growth factor-1 gene transfection can significantly improve the proliferation and mechanical properties of rabbit adipose mesenchymal stem cells; the two have synergistic effect.

In-situ fabrication of a spherical-shaped Zn-Al hydrotalcite with BiOCl and study on its enhanced photocatalytic mechanism for perfluorooctanoic acid removal performed with a response surface methodology.

Perfluorooctanoic acid (PFOA), a widely used compound, is harmful to the environment and human health. In this study, a facile one pot solvothermal method of integrating BiOCl with Zn-Al hydrotalcite to form spherical-shaped BiOCl/Zn-Al hydrotalcite (B-BHZA) sample is reported. The characteristics and main factors affecting photocatalytic PFOA and photocatalytic mechanism of BiOCl/Zn-Al hydrotalcite (B-BHZA) are systematically investigated. It is found that spherical-shaped B-BHZA possesses abundant defects and a larger surface area of 64.4 m2 g-1. The factors affecting photocatalytic removal PFOA (e.g., time, pH, initial concentration and dosage) are investigated by modeling the 3D surface response. The removal rate of PFOA is over 90 % in 6 h under UV light at an optimal pH of 2, an initial concentration of 500 µg/L and a dose of dosage 0.5 g/L. The main mechanism occurs by photo-generated h+ oxidation and synergistic effects from the photocatalysis process. Though investigating the intermediates of PFOA degradation and F-, a possibility was proposed that h+ initiated the rapidly decarboxylation of PFOA. The unstable perfluoroheptyl group is formatted and further conversed to short chain perfluorocarboxylic acid. This study provides a new insight for the preparation of highly efficient photocatalysts to the treatment of halogenated compounds in UV system.

Three-dimensionally macroporous MnZrOx catalysts for propane combustion: Synergistic structure and doping effects on physicochemical and catalytic properties.

Three-dimensionally macroporous (3DM) MnZrOx catalysts were fabricated to reveal the structure and Zr-doping effects on both physicochemical properties and propane combustion behaviors. The increasing addition of zirconium is favorable for the formation of 3DM structure and amorphous Mn-Zr solid solution, leading to tunable physicochemical properties. The significant activity improvement after zirconium addition was originally attributable to the superior redox ability, higher oxygen mobility and more abundant oxygen vacancy. The excellent catalytic activity, cycling stability and water resistant ability over 3DM Mn0.6Zr0.4Ox make it a promising material for hydrocarbons elimination. The comparative TPSR, in situ DRIFTs and kinetics study over 3DM and bulk catalysts emphasize the advantageous function of 3DM architecture on promoting propane adsorption, oxidation and lattice oxygen mobility.

High-Performance Ag-Cu Nanoalloy Catalyst for the Selective Catalytic Oxidation of Ammonia.

High-performance Ag-Cu alloy nanoparticles (NPs) were successfully synthesized by a solventless mix-bake-wash method and tested for NH3-SCO. The prepared Ag2Cu1 catalyst with a perfect Ag-Cu alloy structure exhibited better T100 (200 °C, the temperature at which 100% NH3 conversion was obtained), higher reaction rates, and lower Ea compared to that with ordinary bimetallic Ag-Cu (AgCuOx). The characterization data revealed much smaller Ag-Cu alloy nanoparticles of the Ag2Cu1 catalyst and more Ag/Cu metallic species on the surface, which can increase the amount of chemisorbed surface oxygen (Oß) and enhance NH3 adsorption and activation in the low-temperature range, therefore leading to a much higher NH3-SCO activity. Kinetic studies and density functional theory calculations indicated that Cu decoration at Ag by Ag-Cu alloying could enhance the adsorption/activation of NH3 and O2. It has been found that O2 was more easily transformed from the adsorption state to the transition state than NH3, which enhanced the performance of NH3 oxidation. In addition, the Ag2Cu1 catalyst exhibited excellent durability because of the stabilization of Ag sites by the Ag-Cu alloy structure.

Hierarchical Fe3O4@carbon@MnO2 hybrid for electromagnetic wave absorber.

In this work, a novel Fe3O4@C@MnO2 hybrid was successfully synthesized via facile method. The morphology, structure, chemical composition, magnetic behavior and EM wave absorbing performance of the hybrid were systematically investigated. Results indicate that the hybrid possesses uniform hierarchical and mesoporous structure. The magnetic saturation(Ms) value of the hybrid is 19.8 emu g-1, which is beneficial to improve magnetic loss. According to its reflection loss curve, the hybrid performs superior EM wave absorption capacity, with a minimum reflection loss value and effective absorbing bandwidth of -35 dB and 5 GHz when the specimen thickness is 2.7 mm. The excellent performance of this hybrid can mainly be attributed to its ideal matching of magnetic loss and dielectric loss, large specific surface area, mesoporous structure and interfacial polarizations. Such new material has the potential to be a superior electromagnetic wave absorber, or applied as a functional filler to modify resin matrix.

Nickel nanoparticles inlaid in lignin-derived carbon as high effective catalyst for lignin depolymerization.

Ni nanoparticles inlaid in lignin-derived carbon constructing the "inlaid type" Ni/C-I was reported to improve stability and adjust metal-support interaction of lignin hydrogenolysis catalyst. The Ni/C-I was further heat treated in air to prepare Ni/C-R so as to re-expose the blocked active sites by carbon species. A lot of characterization techniques were carried out to confirm the "inlaid structure" of the catalysts. The lignin depolymerization results demonstrated that the Ni/C-R had better catalytic performance than traditional "supported type" Ni/C, 23.3% aromatic monomer yield and 82.4% bio-oil yield were achieved. Moreover, the mechanism studies with lignin model compound revealed that Ni/C-R had better bond breaking ability than Ni/C, even CC bond could be cleaved. The electron effect could be responsible for that, since the electrons could transfer from Ni0 to carbon support for Ni/C-R, which could improve the bond breaking ability.

Hepatocyte nuclear factor 1 alpha (HNF1A) regulates transcription of O-GlcNAc transferase in a negative feedback mechanism.

O-GlcNAc transferase (OGT)-catalyzed protein O-GlcNAcylation is implicated in diverse cellular events. In the present study, we report the regulation of ogt transcription by the hepatocyte nuclear factor 1 homologue A (HNF1A) in HEK293T cells. We first identified a core ogt promoter (-150 to +200 bp) and confirmed its binding to the transcription factor HNF1A. We found that HNF1A regulates ogt transcription in a time-dependent manner and that O-GlcNAcylation of HNF1A represses ogt transcription. Electron-transfer dissociation based tandem mass spectrometry analysis revealed 14 O-GlcNAc sites on HNF1A, six of which are predominantly modified, including Ser303/304 , Ser471 , Ser560 and Thr563/564 . We further found that loss of O-GlcNAcylation at Ser303/304 or Thr563/564 significantly elevates ogt transcription. These findings highlight a negative feedback mechanism for ogt transcription, which partially explains the homeostasis of cellular O-GlcNAcylation.

Self-emulsifying drug delivery system improves preventive effect of curcuminoids on chronic heart failure in rats.

Several studies have reported the preventive or therapeutic effect of curcuminoids on chronic heart failure (CHF), but their application was limited due to low solubility and bioavailability. Our previous study indicates that self-emulsifying drug delivery system (SEDDS) improves the solubility and bioavailability of curcuminoids. Thus, the aim of this work was to investigate whether SEDDS could improve preventive effect of curcuminoids on CHF in rats. CHF model was were established by coronary artery ligation. Ninety rats were randomly and averagely divided into sham, model, low- or high-dose suspension or SEDDS of curcuminoids (66.68 or 266.68 mg/kg) groups. Hemodynamic indices were recorded by multipurpose polygraph. Serum oxidative indices, B-type natriuretic peptide (BNP) and heart weight index were determined by kits and electronic balance. Myocardial infarct area, ventricular dilatation degree and collagen volume fraction of myocardial interstitium were analyzed by Masson staining, picric acid and sirius red staining, light microscopy and image analysis system. Myocardial histopathology was observed by hematoxylin and eosin staining, Masson staining and light microscopy. Reduction of ventricular pump function, increase of BNP level and heart weight index, myocardial lipid peroxidation damage, myocardial infarction, myocardial fibrosis, and cardiac enlargement were detected or observed in model group relative to those in sham group. After treatment with suspension or SEDDS of curcuminoids, the above-mentioned pathological changes were obviously reversed relative to those in model group. Meanwhile, the ameliorative effect of SEDDS of curcuminoids was markedly better than that of suspension of curcuminoids. This work provides a valuable reference from pharmacodynamics for development of curcuminoids pharmaceutics.

An immunosuppressive function of interleukin-35 in chronic hepatitis C virus infection.

Interleukin (IL)-35, a newly identified member of the IL-12 cytokine family, has been reported to suppress inflammation and induce immunotolerance. However, little is known regarding the role of IL-35 during chronic hepatitis C virus (HCV) infection. Herein, we measured the serum IL-35 concentration of 73 patients with hepatitis C and 22 healthy individuals, as well as further investigated the modulatory function of IL-35 on CD4+CD25+CD127dim/- regulatory T cells (Tregs) and on hepatocytes infected with HCV in cell culture (HCVcc). IL-35 expression was significantly increased in patients with chronic hepatitis C and was positively correlated with the levels of HCV RNA. Inhibition of viral replication led to decreases in the serum levels of IL-35. IL-35 stimulation not only elevated the percentage of Tregs but also robustly inhibited cellular proliferation and up-regulated the production of anti-inflammatory cytokines (e.g., IL-10 and IL-35) in a HCV-specific and non-specific manner, which indicates enhancement of the suppressive function of Tregs. Although IL-35 did not exert anti-HCV activity in HCVcc-infected Huh7.5 cells, it reduced inflammatory cytokine secretion from Huh7.5 cells. This was probably via inhibition of the STAT1 and STAT3 signaling pathways, which could suppress subsequent liver damage due to chronic hepatitis C. The current data suggested that IL-35 contributes to persistent HCV infection by inhibiting antiviral immune activity. Moreover, IL-35 might also protect against HCV-induced liver injury by down-regulating the expression of proinflammatory cytokines. Thus, the immunosuppressive properties of IL-35 might play contradictory roles in maintaining viral persistence and reducing the inflammatory responses in chronic HCV infection.