Synthesis of Metal-Nitrogen-Carbon Electrocatalysts with Atomically Regulated Nitrogen-Doped Polycyclic Aromatic Hydrocarbons.

Tuning the active site structure of metal-nitrogen-carbon electrocatalysts has recently attracted increasing interest. Herein, we report a bottom-up synthesis strategy in which atomically regulated N-doped polycyclic aromatic hydrocarbons (N-PAHs) of NxC42-x (x = 1, 2, 3, 4) were used as ligands to allow tuning of the active site's structures of M-Nx and establish correlations between the structures and electrocatalytic properties. Based on the synthesis process, detailed characterization, and DFT calculation results, active structures of Nx-Fe1-Nx in Fe1-Nx/RGO catalysts were constructed. The results demonstrated that the extra uncoordinated N atoms around the Fe1-N4 moieties disrupted the π-conjugated NxC42-x ligands, which led to more localized electronic state in the Fe1-N4 moieties and superior catalytic performance. Especially, the Fe1-N4/RGO exhibited optimized performance for ORR with E1/2 increasing by 80 mV and Jk at 0.85 V improved 18 times (compared with Fe1-N1/RGO). This synthesis strategy utilizing N-PAHs holds significant promise for enhancing the controllability of metal-nitrogen-carbon electrocatalyst preparation.

Constructing Heptazine-COF@TiO2 Heterojunction Photocatalysts for Efficient Photodegradation of Acetaminophen under Visible Light.

Constructing heterojunction photocatalysts are widely applied to boost the photocatalytic activity of materials. Here, a novel covalent organic framework (COF) material with heptazine units was developed and hybridized with TiO2 nano particles (NPs) to fabricate the Heptazine-COF@TiO2 photocatalysts for acetaminophen (AAP) photodegradation. The successfully assembled heptazine unit endows the Heptazine-COF with outstanding semiconductor property (optical bandgap is 2.53 eV). The synthesized Heptazine-COF@TiO2 hybrids is proved to have the heterojunction structure with high visible light activity and fast charge-carrier mobility, and exhibits better performance in photodegradation of AAP under visible light. The excellent photodegradation efficiency (rate constant: 0.758 min-1) and high reusability (rate constant: 0.452 min-1 in the 6th cycles) of the optimized sample outperform the traditional inorganic photocatalysts and other heterojunction photocatalysts. In addition, these photocatalysts present universal degradation activity for other dyes and antibiotics.

Carbohydrate metabolism and cytology of S-type cytoplasmic male sterility in wheat.

Introduction: Cytoplasmic male sterility (CMS) is an important tool for hybrid heterosis utilization. However, the underlying mechanisms still need to be discovered. An adequate supply of nutrients is necessary for anther development; pollen abortion would occur if the metabolism of carbohydrates were hampered. Methods: In order to better understand the relationship between carbohydrate metabolism disorder and pollen abortion in S-CMS wheat, the submicroscopic structure of wheat anthers was observed using light microscopy and transmission electron microscopy; chloroplast proteome changes were explored by comparative proteomic analysis; sugar measuring and enzyme assays were performed; and the expression patterns of carbohydrate metabolism-related genes were studied using quantitative real-time PCR (qRT-PCR) method. Results: These results indicated that the anther and microspore in S-CMS wheat underwent serious structural damage, including premature tapetum degeneration, nutritional shortage, pollen wall defects, and pollen grain malformations. Furthermore, the number of chloroplasts in the anthers of S-CMS lines decreased significantly, causing abnormal carbohydrate metabolism, and disintegration of osmiophilic granules and thylakoids. Meanwhile, some proteins participating in the Calvin cycle and carbohydrate metabolism were abnormally expressed in the chloroplasts of the S-CMS lines, which might lead to chloroplast dysfunction. Additionally, several key enzymes and genes related to carbohydrate metabolism were significantly inhibited in S-CMS. Discussion: Based on these results, we proposed a carbohydrate metabolism pathway for anther abortion in S-type cytoplasmic male sterility, which would encourage further exploration of the pollen abortion mechanisms for CMS wheat.

Multiple roles of wheat ferritin genes during stress treatment and TaFER5D-1 as a positive regulator in response to drought and salt tolerance.

Ferritin not only regulates the plant's iron content but also plays a significant role in the plant's development and resistance to oxidative damage. However, the role of the FER family in wheat has not been systematically elucidated. In this study, 39 FERs identified from wheat and its ancestral species were clustered into two subgroups, and gene members from the same group contain relatively conservative protein models. The structural analyses indicated that the gene members from the same group contained relatively conserved protein models. The cis-acting elements and expression patterns analysis suggested that TaFERs might play an important role combating to abiotic and biotic stresses. In the transcriptional analysis, the TaFER5D-1 gene was found to be significantly up-regulated under drought and salt stresses and was, therefore, selected to further explore the biological functions Moreover, the GFP expression assay revealed the subcellular localization of TaFER5D-1 proteins in the chloroplast, nucleus, membrane and cytoplasm. Over-expression of TaFER5D-1 in transgenic Arabidopsis lines conferred greater tolerance to drought and salt stress. According to the qRT-PCR data, TaFER5D-1 gene over-expression increased the expression of genes related to root development (Atsweet-17 and AtRSL4), iron storage (AtVIT1 and AtYSL1), and stress response (AtGolS1 and AtCOR47). So it is speculated that TaFER5D-1 could improve stress tolerance by promoting root growth, iron storage, and stress-response ability. Thus, the current study provides insight into the role of TaFER genes in wheat.

Efficient Inverted Perovskite Solar Cells Enabled by Dopant-Free Hole-Transporting Materials Based on Dibenzofulvene-Bridged Indacenodithiophene Core Attaching Varying Alkyl Chains.

Inspired by the structural advantages of spiro-OMeTAD, which is the most commonly used hole-transporting material (HTM), two rationally designed HTMs with butterfly-shaped triarylamine groups based on dibenzofulvene-bridged indacenodithiophene (IDT) core (attaching hexyl and octyl chains) have been synthesized, namely, IT-C6 and IT-C8, respectively. Shorter alkyl-chain-based IT-C6 exhibits a marked increase in glass-transition temperature (Tg) of 105 °C, whereas IT-C8 shows a Tg of 95 °C. Moreover, it is demonstrated that IT-C6 exhibits a higher hole-transporting mobility, more suitable band energy alignment, better interfacial contact, and passivation effect. The inverted devices of employed HTM based on IT-C6 obtained a champion PCE of 18.34% with a remarkable fill factor (FF) of 82.32%, whereas the IT-C8-based device delivered an inferior PCE of 16.94% with an FF up to 81.20%. Both HTMs embodied inverted devices present high FF values greater than 81%, which are among the highest reported values of small molecular HTM-based PSCs. This work reveals that cutting off the symmetrical spiro-core and subsequently combining IDT (attaching tailored alkyl chains) with the spiro-linkage fluorine to construct the orthogonal molecular conformation is a significant principle for the design of promising dopant-free HTMs.

Gene Expression Profiles Underlying Selective T-Cell-Mediated Immunity Activity of a Chinese Medicine Granule on Mice Infected with Influenza Virus H1N1.

A Chinese medicine granule, Shu-Feng-Xuan-Fei (SFXF), is critical for viral clearance in early phase of influenza virus infection. In this study, 72 ICR mice were randomly divided into six groups: normal control group, virus control group, Oseltamivir group, low-dose SFXF, medium-dose SFXF, and high-dose SFXF. Mice were anesthetized and inoculated with 4LD50 of influenza virus A (H1N1) except normal control group. Oseltamivir group received 11.375 mg·kg(-1) ·d(-1) Oseltamivir Phosphate. SFXF 3.76, 1.88 and 0.94 g·kg(-1) ·d(-1) were administrated to mice in all SFXF groups. Each group was in equal dose of 0.2ml daily for 4 consecutive days. Mice were sacrificed and then total RNA was extracted in lung tissue. Some genes involved in T-cell-mediated immunity were selected by DNA microarray. These candidate genes were verified by Real-Time PCR and western immunoblotting. Compared with virus control group, in Toll-like receptor signaling pathway, 12 virus-altered genes were significantly reduced following medium-dose SFXF treatment. Eighteen antigen processing presentation-associated genes were upregulated by medium-dose SFXF. In the process of T cell receptor signaling pathway, 19 genes were downregulated by medium-dose SFXF treatment. On exploration into effector T cells activation and cytokines, all of altered genes in virus control group were reversed by medium-dose SFXF. Real-time PCR and western immunoblotting showed that the regulation of medium-dose SFXF in IL-4, IFN-γ, TNF-α, IL-1ß, TLR7, MyD88, p38, and JNK was superior to Oseltamivir and high-dose SFXF group. Therefore, SFXF granules could reduce influenza infected cells and activation of T cells.

Combined bioremediation of atrazine-contaminated soil by Pennisetum and Arthrobacter sp. strain DNS10.

Strain DNS10 was isolated from the black soil collected from the northeast of China which had been cultivated with atrazine as the sole nitrogen source. Pennisetum is a common plant in Heilongjiang Province of China. The main objective of this paper was to evaluate the efficiency of plant-microbe joint interactions (Arthrobacter sp. DNS10 + Pennisetum) in atrazine degradation compared with single-strain and single-plant effects. Plant-microbe joint interactions degraded 98.10 % of the atrazine, while single strain and single plant only degraded 87.38 and 66.71 % after a 30-day experimental period, respectively. The results indicated that plant-microbe joint interactions had a better degradation effect. Meanwhile, we found that plant-microbe joint interactions showed a higher microbial diversity. The results of microbial diversity illustrated that the positive effects of cropping could improve soil microbial growth and activity. In addition, we planted atrazine-sensitive plants (soybean) in the soil after repair. The results showed that soybean growth in soil previously treated with the plant-microbe joint interactions treatment was better compared with other treatments after 20 days of growth. This was further proved that the soil is more conducive for crop cultivation. Hence, plant-microbe joint interactions are considered to be a potential tool in the remediation of atrazine-contaminated soil.

Assessment of the ecological security of immobilized enzyme remediation process with biological indicators of soil health.

This study used the enzymes extracted from an atrazine-degrading strain, Arthrobacter sp. DNS10, which had been immobilized by sodium alginate to rehabilitate atrazine-polluted soil. Meanwhile, a range of biological indices were selected to assess the ecological health of contaminated soils and the ecological security of this bioremediation method. The results showed that there was no atrazine detected in soil samples after 28 days in EN+AT (the soil containing atrazine and immobilized enzyme) treatment. However, the residual atrazine concentration of the sample in AT (the soil containing atrazine only) treatment was about 5.02 ± 0.93 mg kg(-1). These results suggest that the immobilized enzyme exhibits an excellent ability in atrazine degradation. Furthermore, the immobilized enzyme could relieve soil microbial biomass carbon and soil microbial respiration intensity to 772.33 ± 34.93 mg C kg(-1) and 5.01 ± 0.17 mg CO(2) g(-1) soil h(-1), respectively. The results of the polymerase chain reaction-degeneration gradient gel electrophoresis experiment indicated that the immobilized enzyme also could make the Shannon-Wiener index and evenness index of the soil sample increase from 1.02 and 0.74 to 1.51 and 0.84, respectively. These results indicated that the immobilized enzymes not only could relieve the impact from atrazine on the soil, but also revealed that the immobilized enzymes did no significant harm on the soil ecological health.