Yellow–colored mesoporous pure titania and its high stability in visible light photocatalysis

AbstractYellow–colored pure titania with a mesoporous structure was prepared by the aggregate of titania nanocrystals, which were stabilized by exfoliated titanate nanosheets via an electrostatic interaction. X–ray diffraction patterns and images of transmission electron microscope confirm that titanate sheets are randomly dispersed into the assembled titania nanocrystals without forming any self–restacked phase. This nanocrystals–nanosheets composite exhibits a mesoporous structure with pore size of ~6.5nm and surface area of 236.3m2g−1. Greatly different from the UV–responded properties of titania nanocrystals and titanate nanosheets, the absorption edge of nanocomposite red–shifts to visible light region. The visible light photocatalytic tests demonstrate that this nanocomposited titania shows excellent activity for the degradation of organic dyes, as well as a colorless organic pollutant of 2, 4–dichlorophenol. The possible photocatalytic mechanism that photogenerated holes as the mainly oxidant species in photocatalysis is proposed based on the trapping experiments of hydroxyl radicals or photogenerated holes. Moreover, as the nanocomposite depicts an extreme stability, no obvious deactivation occurs after five cycles

cis-Tetra­aqua­bis­{5-[4-(1H-imidazol-1-yl-κN 3)phen­yl]tetra­zolido}manganese(II) dihydrate

In the title compound, [Mn(C10H7N6)2(H2O)4]·2H2O, the complex unit comprises an Mn2+ ion, coordinated by two imidazole N atoms from cis-related monodentate 5-[4-(imidazol-1-yl)phen­yl]tetra­zolide ligands and four water mol­ecules, together with two water mol­ecules of solvation. The Mn2+ ion lies on a twofold rotation axis and has a slightly distorted octa­hedral geometry. The mol­ecules are connected by O—H⋯N and O—H⋯O hydrogen bonds involving both coordinated and solvent water mol­ecules, generating a three-dimensional structure. Two C atoms of the imidazole ring of the ligand are each disordered over two sites with occupancy factors of 0.75 and 0.25

catena-Poly[[(2,2′-bipyridine)­manganese(II)]-μ3-4,4′-sulfonyl­dibenzoato]

In the title compound, [Mn(C14H8O6S)(C10H8N2)]n, the MnII ion is coordinated by four O atoms from three 4,4′-sulfonyl­dibenzoate (sdba) ligands and two N atoms from one 2,2′-bipyridine (2,2′-bipy) ligand in a distorted octa­hedral geometry. The manganese atoms are alternately bridged either by two sdba ligands, with an Mn⋯Mn separation of 12.284 (1) Å, or by two carboxyl­ate groups from two sdba ligands, with an Mn⋯Mn separation of 4.064 (1) Å, thus producing polymeric chains propagated in [101]. Weak inter­molecular C—H⋯O hydrogen bonds and π–π inter­actions [centroid–centroid distance of 3.730 (3) Å between the aromatic rings of neighbouring polymeric chains] further stabilize the crystal packing

WW Domain-Containing Proteins YAP and TAZ in the Hippo Pathway as Key Regulators in Stemness Maintenance, Tissue Homeostasis, and Tumorigenesis

The Hippo pathway is a conserved signaling pathway originally defined in Drosophila melanogaster two decades ago. Deregulation of the Hippo pathway leads to significant overgrowth in phenotypes and ultimately initiation of tumorigenesis in various tissues. The major WW domain proteins in the Hippo pathway are YAP and TAZ, which regulate embryonic development, organ growth, tissue regeneration, stem cell pluripotency, and tumorigenesis. Recent reports reveal the novel roles of YAP/TAZ in establishing the precise balance of stem cell niches, promoting the production of induced pluripotent stem cells (iPSCs), and provoking signals for regeneration and cancer initiation. Activation of YAP/TAZ, for example, results in the expansion of progenitor cells, which promotes regeneration after tissue damage. YAP is highly expressed in self-renewing pluripotent stem cells. Overexpression of YAP halts stem cell differentiation and yet maintains the inherent stem cell properties. A success in reprograming iPSCs by the transfection of cells with Oct3/4, Sox2, and Yap expression constructs has recently been shown. In this review, we update the current knowledge and the latest progress in the WW domain proteins of the Hippo pathway in relevance to stem cell biology, and provide a thorough understanding in the tissue homeostasis and identification of potential targets to block tumor development. We also provide the regulatory role of tumor suppressor WWOX in the upstream of TGF-β, Hyal-2, and Wnt signaling that cross talks with the Hippo pathway

Coordinated regulation of core and accessory genes in the multipartite genome of Sinorhizobium fredii

Prokaryotes benefit from having accessory genes, but it is unclear how accessory genes can be linked with the core regulatory network when developing adaptations to new niches. Here we determined hierarchical core/accessory subsets in the multipartite pangenome (composed of genes from the chromosome, chromid and plasmids) of the soybean microsymbiont Sinorhizobium fredii by comparing twelve Sinorhizobium genomes. Transcriptomes of two S. fredii strains at mid-log and stationary growth phases and in symbiotic conditions were obtained. The average level of gene expression, variation of expression between different conditions, and gene connectivity within the co-expression network were positively correlated with the gene conservation level from strain-specific accessory genes to genus core. Condition-dependent transcriptomes exhibited adaptive transcriptional changes in pangenome subsets shared by the two strains, while strain-dependent transcriptomes were enriched with accessory genes on the chromid. Proportionally more chromid genes than plasmid genes were co-expressed with chromosomal genes, while plasmid genes had a higher within-replicon connectivity in expression than chromid ones. However, key nitrogen fixation genes on the symbiosis plasmid were characterized by high connectivity in both within- and between-replicon analyses. Among those genes with host-specific upregulation patterns, chromosomal znu and mdt operons, encoding a conserved high-affinity zinc transporter and an accessory multi-drug efflux system, respectively, were experimentally demonstrated to be involved in host-specific symbiotic adaptation. These findings highlight the importance of integrative regulation of hierarchical core/accessory components in the multipartite genome of bacteria during niche adaptation and in shaping the prokaryotic pangenome in the long run