Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Towards better photocatalysts: first-principles studies of the alloying effects on the photocatalytic activities of bismuth oxyhalides under visible light

Abstract: Via density functional theory computations, we investigated the photocatalytic activities of pure and alloyed bismuth oxyhalides (BiOXs). The dipole moments of the majority of pure and alloyed BiOXs are larger than 2.00 Debye, which can ensure their high photocatalytic efficiencies. Both the redox potentials of the photon-induced holes and the band gaps increase with an increasing content of lighter halogen atoms in the BiOXs, which competitively affects the photocatalytic efficiency. The hole mobility decreases a lot due to the hybridization of the halogennp states, while the electron mobility is not affected by such hybridization. Therefore, the alloying effect in BiOXs brings about a substantially lower electron–hole recombination rate and, accordingly, a much higher photocatalytic efficiency. Our investigation also suggests that O vacancies, which are energetically more favorable in alloyed BiOXs, could act as capture centers for excited electrons and, consequently, improve the separation of the electron–hole pairs. Our findings present a reasonable explanation for the recent experimental reports and provide some guidance for the design of alloyed BiOX photocatalysts.

SDF-1/CXCR4 axis modulates bone marrow mesenchymal stem cell apoptosis, migration and cytokine secretion

Abstract: Bone marrow mesenchymal stem cells (MSCs) are considered as a promising cell source to treat the acute myocardial infarction. However, over 90% of the stem cells usually die in the first three days of transplantation. Survival potential, migration ability and paracrine capacity have been considered as the most important three factors for cell transplantation in the ischemic cardiac treatment. We hypothesized that stromal-derived factor-1 (SDF-1)/CXCR4 axis plays a critical role in the regulation of these processes. In this study, apoptosis was induced by exposure of MSCs to H2O2 for 2 h. After re-oxygenation, the SDF-1 pretreated MSCs demonstrated a significant increase in survival and proliferation. SDF-1 pretreatment also enhanced the migration and increased the secretion of pro-survival and angiogenic cytokines including basic fibroblast growth factor and vascular endothelial growth factor. Western blot and RT-PCR demonstrated that SDF-1 pretreatment significantly activated the pro-survival Akt and Erk signaling pathways and up-regulated Bcl-2/Bax ratio. These protective effects were partially inhibited by AMD3100, an antagonist of CXCR4.We conclude that the SDF-1/CXCR4 axis is critical for MSC survival, migration and cytokine secretion.

Novel triazole-bridged cadmium coordination polymers varying from zero- to three-dimensionality

Abstract: Cadmium salts with different triazole ligands have led to a series of novel triazole−cadmium compounds varying from zero- to three-dimensionality. [Cd2(deatrz)2(H2O)Br4] (1) (deatrz = 3,5-diethyl-4-amino-1,2,4-triazole) is a zero-dimensional complex which uses a triazole ligand together with μ-OH2 as bridges to form a 1D chain via hydrogen-bonding contacts. {[Cd3(deatrz)2Cl6(H2O)2]·2H2O}n (2), {[Cd(dmtrz)Cl2]·1.5H2O}n (3) (dmtrz = 3,5-dimethyl-1,2,4-triazole), and {[Cd3(deatrz)4Cl2(SCN)4]·2H2O}n (4) are polymeric 1D chains. 2 and 4 were constructed via trinuclear cadmium units bridged by triazole ligands and chloride atoms, while 3 consists of μ2-Cl, μ3-Cl, and triazole bridges, cross-linked by hydrogen bonding to give a 3D framework. {[Cd3(dmatrz)4(SCN)6]}n (5) (dmatrz = 3,5-dimethyl-4-amino-1,2,4-triazole) shows a two-dimensional structure whose fundamental units are trinuclear metal cations bridged via triazole ligands. The complex {[Cd(dmtrz)(SCN)2]}n (6) is the first three-dimensional example in N1,N...

Stereodivergent Synthesis of α,α-Disubstituted α-Amino Acids via Synergistic Cu/Ir Catalysis.

Abstract: Cu/Ir dual catalysis has been developed for the stereodivergent α-allylation of aldimine esters. The method enables the preparation of a series of nonproteinogenic α-amino acids (α-AAs) bearing two contiguous stereogenic centers in high yield with excellent stereoselectivity. All four product stereoisomers could be obtained from the same set of starting materials via pairwise combination of two chiral catalysts. Notably, one-pot protocol could be successfully applied for the preparation of the bimetallic Cu/Ir complexes to simplify the manipulation of Cu/Ir dual catalysis. This method could be further utilized for the construction of the key intermediate of a bioactive pyrrolidine derivative and the concise synthesis of a plant growth regulator (2S,3S)-2-amino-3-cyclopropylbutanoic acid.

The m6A Reader ECT2 Controls Trichome Morphology by Affecting mRNA Stability in Arabidopsis

Abstract: The epitranscriptomic mark N6-methyladenosine (m6A) can be written, read, and erased via the action of a complex network of proteins. m6A binding proteins read m6A marks and transduce their downstream regulatory effects by altering RNA metabolic processes. The characterization of m6A readers is an essential prerequisite for understanding the roles of m6A in plants, but the identities of m6A readers have been unclear. Here, we characterized the YTH-domain family protein ECT2 as an Arabidopsis thaliana m6A reader whose m6A binding function is required for normal trichome morphology. We developed the formaldehyde cross-linking and immunoprecipitation method to identify ECT2-RNA interaction sites at the transcriptome-wide level. This analysis demonstrated that ECT2 binding sites are strongly enriched in the 3′ untranslated regions (3′ UTRs) of target genes and led to the identification of a plant-specific m6A motif. Sequencing analysis suggested that ECT2 plays dual roles in regulating 3′ UTR processing in the nucleus and facilitating mRNA stability in the cytoplasm. Disruption of ECT2 accelerated the degradation of three ECT2 binding transcripts related to trichome morphogenesis, thereby affecting trichome branching. The results shed light on the underlying mechanisms of the roles of m6A in RNA metabolism, as well as plant development and physiology.