Dual Channel H2O2 Photosynthesis in Pure Water over S-Scheme Heterojunction Cs3PMo12/CC Boosted by Proton and Electron Reservoirs.

Dual channel photo-driven H2O2 production in pure water on small-scale on-site setups is a promising strategy to provide low-concentrated H2O2 whenever needed. This process suffers, however, strongly from the fast recombination of photo-generated charge carriers and the sluggish oxidation process. Here, insoluble Keggin-type cesium phosphomolybdate Cs3PMo12O40 (abbreviated to Cs3PMo12) is introduced to carbonized cellulose (CC) to construct S-scheme heterojunction Cs3PMo12/CC. Dual channel H2O2 photosynthesis from both H2O oxidation and O2 reduction in pure water has been thus achieved with the production rate of 20.1 mmol L-1 gcat. -1 h-1, apparent quantum yield (AQY) of 2.1% and solar-to-chemical conversion (SCC) efficiency of 0.050%. H2O2 accumulative concentration reaches 4.9 mmol L-1. This high photocatalytic activity is guaranteed by unique features of Cs3PMo12/CC, namely, S-scheme heterojunction, electron reservoir, and proton reservoir. The former two enhance the separation of photo-generated charge carriers, while the latter speeds up the torpid oxidation process. In situ experiments reveal that H2O2 is formed via successive single-electron transfer in both channels. In real practice, exposing the reaction system under natural sunlight outdoors successfully results in 0.24 mmol L-1 H2O2. This work provides a key practical strategy for designing photocatalysts in modulating redox half-reactions in photosynthesis.

Preparation and Post-Assembly Modification of Metallosupramolecular Assemblies from Poly( N-Heterocyclic Carbene) Ligands.

Although the coordination chemistry of N-heterocyclic carbenes (NHCs) with transition metals has been explored for half a century, only in the past ten years has the chemistry of metallosupramolecular assemblies based on poly-NHC ligands been studied more extensively. Remarkable discrete assemblies featuring poly-NHC ligands including two-dimensional metallacycles and three-dimensional metallaprisms/cages have since emerged. These assemblies are mostly obtained starting from various imidazolium or benzimidazolium salts. Driven by the increasing interest in new supramolecular architectures from carbon donor ligands, design, and construction of poly-NHC metal assemblies has become a rapidly growing area of research. The metal-carbene bond length is fixed to approximately 2.0 Å in linear NHC-M-NHC complexes. This allows the use of such complexes bearing olefin-substituted NHC ligands as templates for subsequent photochemical [2 + 2] cycloaddition reactions. The postassembly modification of such assemblies has been actively explored in recent years. In this review, we focus on the synthetic methods, characterization, structural features, and postassembly modifications of metallosupramolecular assemblies obtained from poly-NHC ligands.

[Analysis on SSR information in transcriptome of Astragalus membranaceus var. mongholicus and its polymorphism].

In order to enrich the library of SSR and provide more powerful tools for molecular marker-assisted breeding in Astragalus membranaceus var. mongholicus, simple sequence repeats (SSR) loci in its transcriptome were searched in 18 040 unigenes (>=1 kb) by using MISA. SSR loci information was analyzed and SSR primers were designed by Primer 3. Furthermore, 110 pairs of primers were randomly selected for the polymorphic analysis on 20 plants collected from different habitats. A total of 5 640 SSRs were found in the transcriptome of A. membranaceus var. mongholicus, distributed in 4 462 unigenes with the distribution frequency of 31.26%. SSR loci occurred every 6 514 bp. Mono-nucleotide repeat was the main type, accounted for as much as 36.72% of all SSRs, followed by tri-nucleotide(32.57%) and di-nucleotide(27.73%) repeat motif. Among all 75 repeat types, A/T(2 026) was the predominant one followed by AG/CT(1 179), AAG/CTT(477). For validating the availability of the SSR primers designed using Primer 3, 110 pairs of primers were randomly selected for PCR amplification. Among them, 97 pairs of primers (88.18%) produced clear and reproductive bands. Using 19 pairs of primers showed polymorphism, 20 plants were divded into two groups by UPGMA. There are numerous SSRs in A. membranaceus var. mongholicus transcriptome with high frequency and various types, this will provide the abundant candidate molecular markers for genetic diversity, molecular identification, and marker-assisted breeding study for this plant.

Effects of chloroform extract of Dryopteris crassirhizoma on the ultramicroscopic structures of Meloidogyne incognita.

In our early experiments, the chloroform extract of D. crassirhizoma was demonstrated to contain the highest concentrations of total phloroglucinols among several extract fractions and possessed the most effective nematicidal activity. This study aimed to ascertain the ultrastructural changes in M. incognita after treatment with a D. crassirhizoma chloroform extract at 1 mg·mL⁻¹ for 24 h. It was found that the extract exhibited significant destructive effects on the worm's ultrastructure and caused distinctive damage to body surfaces and internal structures. These results will contribute to a deeper understanding of the nematicidal mechanism of D. crassirhizoma, as well as in the design of efficient bionematicides.

Facile and controllable preparation of carbon microsphere for electro-driven nitrogen reduction: Accommodating nitrogen doping with hierarchical porous structure.

Driven by sustainable electricity, electrochemical nitrogen fixation under ambient conditions is considered as a promising strategy to generate low-concentrated NH3/NH4+. Under the principle of doping and porous engineering, nitrogen-doped carbon microsphere with hierarchical pores (NC-HP) is fabricated via pyrolyzing polymer microsphere. Hierarchical structure with macro-, meso- and micropores is obtained by assembling melamine/phenol-formaldehyde oligomers in Pickering droplets, with the assistance of triblock copolymer Pluronic F127. The regularity of mesopores is strongly affected by melamine to phenol mass ratio. For NC-HP, nitrogen content (N-content) in the carbon matrix can reach as high as 19.1 wt%, yet trade-off effect is observed between N-content and regularity of mesopores. As consequence, NC-HP-3 with N-content of 15.6 wt% and distinct mesopores exhibits the highest catalytic performance. At -0.5 V vs. RHE, NH3/NH4+ production rate and Faradaic efficiency (FE) value reach 15.6 µg∙mgcat.-1∙h-1 and 15.5%, respectively. It shows excellent recyclability, and no degradations are observed with respect to morphology and porous structure. In this hierarchical porous structure, mesopores are expected to facilitate mass transfer for both electrolyte ions and nitrogen, and hence catalytic active sites (e.g. pyrrolic- and pyridinic-N species) in hierarchically mutually connected pores can be well utilized.

External-Shell Oxygen Enabling the Local Environment Modulation of Unsaturated NbN3 for Efficient Electrosynthesis of Hydrogen Peroxide.

Single-atom catalysts with a tunable coordination structure have shown grand potential in flexibly altering the selectivity of oxygen reduction reaction (ORR) toward the desired pathway. However, rationally mediating the ORR pathway by modulating the local coordination number of the single-metal sites is still challenging. Herein, we prepare the Nb single-atom catalysts (SACs) with an external-shell oxygen-modulated unsaturated NbN3 site in carbon nitride and the NbN4 site anchored in nitrogen-doped carbon carriers, respectively. Compared with typical NbN4 moieties for 4e- ORR, the as-prepared NbN3 SACs exhibit excellent 2e- ORR activity in 0.1 M KOH, with the onset overpotential close to zero (9 mV) and the H2O2 selectivity above 95%, making it one of the state-of-the-art catalysts in the electrosynthesis of hydrogen peroxide. Density functional theory (DFT) theoretical calculations indicate the unsaturated Nb-N3 moieties and the adjacent oxygen groups optimize the interface bond strength of pivotal intermediates (OOH*) for producing H2O2, thus accelerating the 2e- ORR pathway. Our findings may provide a novel platform for developing SACs with high activity and tunable selectivity.

Long non-coding RNA DLEU1 promotes malignancy of breast cancer by acting as an indispensable coactivator for HIF-1α-induced transcription of CKAP2.

Earlier studies have suggested deleted in lymphocytic leukemia 1 (DLEU1), a long non-coding RNA, is a prognostic biomarker for breast cancer. Here we explored the malignant behaviors and underlying mechanisms regulated by DLEU1 in breast cancer. We demonstrated that up-regulation of DLEU1 was detected in breast cancer tissues and cells, particularly in tumors of higher malignancy. DLEU1 knockdown inhibited the growth and the motility of breast cancer cells. Mechanistically, DLEU1 interacted with HIF-1α to collectively activate the transcription of CKAP2. By activating ERK and STAT3 signaling, CKAP2 essentially mediated the pro-tumor activities of DLEU1. In vivo, depletion of DLEU1 inhibited xenograft growth and metastasis of breast cancer cells. Therefore, DLEU1, by acting as a coactivator for HIF-1α, up-regulates CKAP2 expression and promotes malignancy of breast cancer. Targeting DLEU1, HIF-1α, or CKAP2 may thus benefit breast cancer treatment.

Chelating Bis(N-Heterocyclic Carbene) Palladium-Catalyzed Reactions.

N-Heterocyclic carbenes (NHCs) have been widely employed in the construction of various metal complexes and applied in the field of catalysis. In this review, a series of palladium complexes comprising chelating bis(NHC) donors (Pd-bis(NHC) complexes) are outlined according to their application in homogeneous catalysis. Examples of metal-organic frameworks containing Pd-bis(NHC) moieties are briefly discussed, in terms of their use in heterogeneous catalysis. The catalytic applications of Pd-bis(NHC) complexes (or moieties in heterogeneous catalysts) are mainly focused on the Mizoroki-Heck, Suzuki-Miyaura, and Sonogashira coupling reactions. Another 14 types of reactions are also summarized beyond these three types of reactions.

Cetylpyridinium chloride mouth rinses alleviate experimental gingivitis by inhibiting dental plaque maturation.

Oral rinses containing chemotherapeutic agents, such as cetylpyridinium chloride (CPC), can alleviate plaque-induced gingival infections, but how oral microbiota respond to these treatments in human population remains poorly understood. Via a double-blinded, randomised controlled trial of 91 subjects, the impact of CPC-containing oral rinses on supragingival plaque was investigated in experimental gingivitis, where the subjects, after a 21-day period of dental prophylaxis to achieve healthy gingivae, received either CPC rinses or water for 21 days. Within-subject temporal dynamics of plaque microbiota and symptoms of gingivitis were profiled via 16S ribosomal DNA gene pyrosequencing and assessment with the Mazza gingival index. Cetylpyridinium chloride conferred gingival benefits, as progression of gingival inflammation resulting from a lack of dental hygiene was significantly slower in the mouth rinse group than in the water group due to inhibition of 17 gingivitis-enriched bacterial genera. Tracking of plaque α and ß diversity revealed that CPC treatment prevents acquisition of new taxa that would otherwise accumulate but maintains the original biodiversity of healthy plaques. Furthermore, CPC rinses reduced the size, local connectivity and microbiota-wide connectivity of the bacterial correlation network, particularly for nodes representing gingivitis-enriched taxa. The findings of this study provide mechanistic insights into the impact of oral rinses on the progression and maturation of dental plaque in the natural human population.

Isolation and sequence analysis of the gene URA3 encoding the orotidine-5'-phosphate decarboxylase from Candida glycerinogenes WL2002-5, an industrial glycerol producer.

The URA3 gene of Candida glycerinogenes WL2002-5, an industrial glycerol producer encoding orotidine-5'-phosphate decarboxylase enzyme, was isolated by complementation cloning in Saccharomyces cerevisiae. DNA sequence analysis revealed the presence of an open reading frame (ORF) of 786 bp, encoding a 262 amino acid protein, which shares 71.65% amino acid sequence similarity to the S. cerevisiae URA3 protein. Furthermore, the cloned ORF fully complemented the ura3 mutation of S. cerevisiae, confirming that it encodes for the C. glycerinogenes Ura3 (CgUra3) protein.

[Study on fermentation condition of alkaline protease gene engineering strain and the purification and characterization of recombinant enzyme].

In a 5L fermentor the production conditions of alkaline protease gene engineering strain BA071 were investigated. The maximum activity of alkaline protease reached 24,480 u/mL in 40 hours of fermentation by combination of enhancing aeration and changing the agitation rate. The fast purification method of recombinant protease was conducted with FPLC (Fast Protein Liquid Chromatography). The crude enzyme, treated with ammonium sulfate fractionation and decolored with DEAE-A-50 and polyethylene glycol concentration, was purified with CM-Sephadex-C-50 and Sephadex-G-75. The purified enzyme appears homologous on SDS-PAGE. The purity of enzyme was increased 76.2 times. SDS-PAGE analysis showed that the molecular weights of expressed recombinant products were about 28 kD. The optimal reaction pH and temperature of recombinant enzyme were at pH11 and 60 degrees C, respectively. The recombinant enzyme exhibited high temperature tolerance and was stable at a wide range of pH. Ca2+, MG2+ can enhance the stability of the recombinant enzyme. While the protease activity of the enzyme was strongly inhibited by Hg2+, Ag+, PMFS [symbol: see text] DFP, and was not affected by SDS and Urea.