Nitrogen Reduction Reaction Catalyzed by Diatomic Metals Supported by N-Doped Graphite

In this article, for the transition metal-nitrogen ligand Mn-M@N6-C (M = Ag, Bi, Cd, Co, Cr, Cu, Fe, Hf, Ir, Mo, Nb, Ni, Os, Pd, Pt, Re, Rh, Ru, Sc, Ta, Tc, V, Y, Zn, Zr, Ti, W), by comparing the amount of change in the length of the N-N triple-bond, and calculating the adsorption energy of N2 and the change of charge around N2, it is shown that the activation effect of Sc, Ti, Y, Nb-Mn@N6-C on the single-atomic layer of graphite substrate is relatively good. The calculation of structural stability shows that the Mn-M@N6-C (M = Sc, Ti, Y) load is relatively stable when it is on the single-atomic layer of the graphite substrate. Through calculations, a series of data such as the adsorption free energy and reaction path are obtained, and the final results show that the preferred reaction mechanism of NRR is the alternating path on Mn-Ti@N6-C, and the reaction limit potential is only 0.16 eV, Mn-Ti@N6-C and has good NRR activity. In addition, the vertical path on Mn-Y@N6-C has a reaction limit potential of 0.39 eV. Mn-Y@N6-C also has good NRR catalyzing activity

Interferon-Induced Protein 6-16 (IFI6-16) from Litopenaeus vannamei Regulate Antiviral Immunity via Apoptosis-Related Genes

A growing number of evidence shows that some invertebrates possess an antiviral immunity parallel to the interferon (IFN) system of higher vertebrates. For example, the IRF (interferon regulatory factor)–Vago–JAK/STAT regulatory axis in an arthropod, shrimp Litopenaeus vannamei (whiteleg shrimp) is functionally similar to the IRF–IFN–JAK/STAT axis of mammals. IFNs perform their cellular immunity by regulating the expression of target genes collectively referred to as IFN-stimulated genes (ISGs). However, the function of invertebrate ISGs in immune responses is almost completely unclear. In this study, a potential ISG gene homologous to the interferon-induced protein 6-16 (IFI6-16) was cloned and identified from L. vannamei, designated as LvIFI6-16. LvIFI6-16 contained a putative signal peptide in the N-terminal, and a classic IFI6-16-superfamily domain in the C-terminal that showed high conservation to other homologs in various species. The mRNA levels of LvIFI6-16 were significantly upregulated after the stimulation of poly (I:C) and challenges of white spot syndrome virus (WSSV). Moreover, silencing of LvIFI6-16 caused a higher mortality rate and heightened virus loads, suggesting that LvIFI6-16 could play a crucial role in defense against WSSV. Interestingly, we found that the transcription levels of several caspases were regulated by LvIFI6-16; meanwhile, the transcription level of LvIFI6-16 self was regulated by the JAK/STAT cascade, suggesting there could be a JAK/STAT–IFI6-16–caspase regulatory axis in shrimp. Taken together, we identified a crustacean IFI6-16 gene (LvIFI6-16) for the first time, and provided evidence that the IFI6-16 participated in antiviral immunity in shrimp

Rationally Designed Surfactants for Few-Layered Graphene Exfoliation: Ionic Groups Attached to Electron-Deficient π‑Conjugated Unit through Alkyl Spacers

Mass production of graphene with low cost and high throughput is very important for practical applications of graphene materials. The most promising approach to produce graphene with low defect content at a large scale is exfoliation of graphite in an aqueous solution of surfactants. Herein, we report a molecular design strategy to develop surfactants by attaching ionic groups to an electron-deficient π-conjugated unit with flexible alkyl spacers. The molecular design strategy enables the surfactant molecules to interact strongly with both the graphene sheets and the water molecules, greatly improving graphene dispersion in water. As the result, a few-layered graphene concentration as high as 1.2–5.0 mg mL^–1 is demonstrated with the surfactant, which is much higher than those (<0.1 mg mL^–1) obtained with normal aromatic or nonaromatic surfactants. Moreover, the surfactant can be easily synthesized at large scale. The superior performance and convenient synthesis make the surfactant very promising for mass production of graphene

Synergistically boosting highly selective CO2-to-CO photoreduction over BiOCl nanosheets via in-situ formation of surface defects and non-precious metal nanoparticles

Hollow hierarchical BiOCl (BOC) assembled by nanosheets with highly exposed (001) facet is synthesized via a gas-bubble-template strategy. The as-synthesized BOC is further modified by thermal treatment in N2 to in-situ introduce oxygen vacancies (OVs) and metallic bismuth (Bi0) nanoparticles from the BOC lattice (Bi0/OVs-BOC). Thermal treatment in N2 enables an intimate contact between OVs-BOC and Bi0 nanoparticles, which is conducive to the transfer of photogenerated charge carriers. In CO2 photoreduction test, the Bi0/OVs-BOCs exhibit almost 100 % selectivity towards CO, and some of the samples also have a significant increase in yield. For instance, BOC-250 shows about 24.82 mu mol center dot g-1 h-1 CO2-to- CO photoreduction efficiency which is nearly four times higher than that of the BOC with high stability. It is found that suitable energy band structure and desirable intrinsic carrier mobility account for the substantial enhancement of CO2-to- CO photoreduction activity due to the in-situ introduction of OVs and Bi0 nanoparticles. Density functional theory (DFT) calculations unveil that the decreased reaction energy, the weakened adsorption energy for CO, and suitable adsorption energy for H and OH of Bi0/OVs-BOC lead to high selectivity. This work sheds light on the synergistic effect of insitu formed OVs and metal nanoparticles on enhancing the photocatalytic activity and selectivity of solar energy materials

Theoretical Insights on the C₂H_<i>y</i> Formation Mechanism During CH₄ Dissociation on Cu(100) Surface

The possible C₂H_<i>y</i> (<i>y</i> = 2–6) formation reactions (CH_<i>x</i> + CH_<i>z</i> → C₂H_<i>y</i> (<i>y</i> = <i>x</i> + <i>z</i>)) and activated second-order CH_<i>x</i>+1 + CH_<i>z</i>–1 reactions (CH_<i>x</i> + CH_<i>z</i> → CH_<i>x</i>+1 + CH_<i>z</i>–1) during CH₄ dissociation on Cu(100) surface have been investigated by using the density functional theory. Our results show that C₂H_<i>y</i> (<i>y</i> = 2, 4) formation reactions are favorable both kinetically and thermodynamically, compared with the direct dehydrogenation of CH₄ (CH_<i>x</i> → CH_<i>x</i>–1 + H) and second-order CH_<i>x</i>+1 + CH_<i>z</i>–1 reactions. The second-order CH_<i>x</i>+1 + CH_<i>z</i>–1 reactions are less competitive compared with the direct dehydrogenation of CH_<i>x</i>. Both DFT calculations and microkinetic model demonstrate that the reaction CH + CH → C₂H₂ is a major channel to produce C₂H_<i>y</i> at a temperature of 860 °C, followed by CH₃ + CH → C₂H₄. When the H₂ influence is introduced, the major intermediate changes from CH to CH₃ on Cu(100) surface with the increase of H₂ partial pressure, while the coverage difference between CH and CH₃ is not significant. This means that both species will have a large influence on the graphene growth mechanism

Identification, characterization, and function analysis of the Cactus gene from Litopenaeus vannamei.

The nuclear factor-kappa B (NF-κB) pathways play important roles in innate immune responses. IκB is the main cytoplasmic inhibitor of NF-κB. In this study, we identified the LvCactus gene from Litopenaeus vannamei, which is the first cloned IκB homologue in subphylum Crustacea. LvCactus contains six predicted ankyrin repeats, which show similarities to those of Cactus proteins from insects. LvCactus localizes in cytoplasm and interacts with LvDorsal, an L. vannamei homologue to Drosophila melanogaster Dorsal belonging to class II NF-κB family, to prevent its nuclear translocation. Contrary to that of LvDorsal, over-expression of LvCactus down-regulates the activities of shrimp antimicrobial peptides promoters, suggesting LvCactus is an inhibitor of LvDorsal. The promoter of LvCactus was predicted to contain five putative NF-κB binding motifs, among which four were proved to be bound by LvDorsal by chromatin immunoprecipitation assays. Dual-luciferase reporter assays also showed that transcription of LvCactus was promoted by LvDorsal but inhibited by LvCactus itself, indicating a feedback regulatory pathway between LvCactus and LvDorsal. Expression of LvCactus was up-regulated after Lipopolysaccharides, poly (I:C), Vibrio parahaemolyticus, and Staphylococcus aureus injections, suggesting an activation response of LvCactus to bacterial and immune stimulant challenges. Differently, the LvCactus expression levels obviously decreased during white spot syndrome virus (WSSV) infection, indicating the feedback regulatory pathway of LvCactus/LvDorsal could be modified by WSSV