Selective Passivation of Pt Nanoparticles with Enhanced Sintering Resistance and Activity toward CO Oxidation via Atomic Layer Deposition

A selective atomic-layer-deposition method is developed to decorate platinum (Pt) nanoparticles (NPs) with nickel oxides (NiO_<i>x</i>), resulting in greatly improved catalytic performance. During the initial growth stage, NiO_<i>x</i> can be selectively deposited on the low coordinated sites of Pt NPs. Selectivity is realized through intrinsic binding energy differences of nickel (Ni) precursor on Pt sites, which has been confirmed by Fourier transform infrared characterizations and density functional theory simulations. The NiO_<i>x</i>/Pt/Al₂O₃ catalysts show enhanced activity toward CO oxidation, which is mainly due to the highly active metal oxide interfaces created. More importantly, the sintering resistance of the composite NiO_<i>x</i>/Pt/Al₂O₃ catalysts has been improved significantly, which can be attributed to the stabilization of volatile atoms at low coordinated sites and the strong metal oxide interaction that anchors Pt NPs. This study reveals that selective passivation is an effective method to simultaneously enhance the catalytic activity and stability

Genetic Variants of <i>BMP2</i> and Their Association with the Risk of Non-Syndromic Tooth Agenesis

<div><p>Non-syndromic tooth agenesis (or non-syndromic congenitally missing tooth) is one of the most common congenital defects in humans affecting the craniofacial function and appearance. Single nucleotide polymorphisms (SNPs) have been associated with an individual’s susceptibility to these anomalies. The aim of the present study was therefore to investigate the roles of the potentially functional SNPs of <i>BMP2</i> in the occurrence of tooth agenesis. Overall, four potentially functional SNPs of <i>BMP2</i> (rs15705, rs235768, rs235769 and rs3178250) were selected, and their associations with the susceptibility of tooth agenesis were evaluated in a case-control study of 335 non-syndromic tooth agenesis cases and 444 healthy controls. The SNPs rs15705 and rs3178250 were found to be associated with an individual’s risk of tooth agenesis (<i>P</i> = 0.046 and <i>P</i> = 0.039, respectively). Both SNPs showed an increased risk of mandibular incisor agenesis (rs15705, AA/AC <i>vs</i>. CC = 1.58, 95% CI = [1.06–2.34], <i>P</i> = 0.024; rs3178250, TT/TC <i>vs</i>. CC = 1.60, 95% CI = [1.08–2.37], <i>P</i> = 0.020). Bioinformatics analysis indicated that these two SNPs located at the 3’-untranslated region (3’-UTR) of <i>BMP2</i> might alter the binding ability of miR-1273d and miR-4639-5p, respectively, which was confirmed by luciferase activity assays in the 293A and COS7 cell lines (<i>P</i> < 0.001 in 293A and <i>P</i> < 0.01 in COS7 for miR-1273d; and <i>P</i> < 0.001 in both cells for miR-4639-5p). Furthermore, <i>BMP2</i> mRNA expression decreased after transfecting either miR-1273d or miR-4639-5p into these two cell lines (<i>P</i> < 0.01 in 293A and <i>P</i> < 0.001 in COS7 for miR-1273d, and <i>P</i> < 0.01 in both cell lines for miR-4639-5p). Taken together, our findings indicate that rs15705 and rs317250 are associated with the susceptibility of non-syndromic tooth agenesis by possibly affecting miRNAs and mRNA interaction.</p></div

Association of <i>BMP2</i> SNPs and risk of mandibular incisor agenesis.

<p>Association of <i>BMP2</i> SNPs and risk of mandibular incisor agenesis.</p

Distributions of congenitally missing tooth.

<p>Distributions of congenitally missing tooth.</p

<i>BMP2</i> mRNA expression in cells after transfenction with miRNA mimics.

<p>MiR-1273d mimics (A) or miR-4639-5p mimics (B) were transfected into 293A or COS7 cells. Transcript levels were analyzed by qPCR and normalized to <i>GAPDH</i> levels. Error bars indicate the +SD obtained from three independent experiments following three replicates.</p

The renilla-to-firefly luminescence ratio comparison when co-transfecting 293A and COS7 cells with the <i>BMP2</i> 3’-UTR reporter and miR-mimics.

<p>PsiCHECK-2 without the insert or with the WT or MT plasmids was transfected respectively (A) or co-transfected with the miR-1273d mimics (B) or miR-4639-5p mimics (C) in the 293A and COS7 cell lines. Data were derived from three independent experiments with three replicates.</p