In Situ Structure of a Mo-Doped Pt-Ni Catalyst during Electrochemical Oxygen Reduction Resolved from Machine Learning-Based Grand Canonical Global Optimization.

Pt-Ni alloy is by far the most active cathode material for oxygen reduction reaction (ORR) in the proton-exchange membrane fuel cell, and the addition of a tiny amount of a third-metal Mo can significantly improve the catalyst durability and activity. Here, by developing machine learning-based grand canonical global optimization, we are able to resolve the in situ structures of this important three-element alloy system under ORR conditions and identify their correlations with the enhanced ORR performance. We disclose the bulk phase diagram of Pt-Ni-Mo alloys and determine the surface structures under the ORR reaction conditions by exploring millions of likely structure candidates. The pristine Pt-Ni-Mo alloy surfaces are shown to undergo significant structure reconstruction under ORR reaction conditions, where a surface-adsorbed MoO4 monomer or Mo2O x dimers cover the Pt-skin surface above 0.9 V vs RHE and protect the surface from Ni leaching. The physical origins are revealed by analyzing the electronic structure of O atoms in MoO4 and on the Pt surface. In viewing the role of high-valence transition metal oxide clusters, we propose a set of quantitative measures for designing better catalysts and predict that six elements in the periodic table, namely, Mo, Tc, Os, Ta, Re, and W, can be good candidates for alloying with PtNi to improve the ORR catalytic performance. We demonstrate that machine learning-based grand canonical global optimization is a powerful and generic tool to reveal the catalyst dynamics behavior in contact with a complex reaction environment.

Knockout of ALOX12 protects against spinal cord injury-mediated nerve injury by inhibition of inflammation and apoptosis.

Spinal cord injury (SCI) is terrible damage leading to the deficiencies and results in infinite inconvenience to sufferers. The effective treatment for SCI still meets a larger number of problems. Herein, the underlying molecular mechanism and novel therapy of SCI are urgently to investigate. Arachidonate 12-lipoxygenase (ALOX12) is widely expressed in various cell types and plays important role in modulating different cellular processes, such as platelet aggregation, cell migration and cancer cell proliferation. Nevertheless, the effects of ALOX12 on SCI are unclear. In the study, SCI model was established in wild type (WT) mice and ALOX12 knockout mice. First, ALOX12 expression was up-regulated in spinal cord tissues of WT mice after SCI. ALOX12-knockout mice exhibited improved behavior after SCI operation. Glial activation triggered by SCI was also alleviated in mice with the loss of ALOX12, as evidenced by the down-regulated expression of glial fibrillary acidic protein (GFAP) and Iba-1 in spinal cord samples. Further, SCI-induced inflammation was markedly prevented in ALOX12-knockout mice through blocking inhibitor of NF-κB α (IκBα)/nuclear factor-κB (NF-κB) pathway signaling. Additionally, reducing ALOX12 expression attenuated apoptosis in spinal cord tissues of SCI mice by decreasing Cyto-c, cleaved Caspase-3 and poly (ADP-ribose) polymerases (PARP) expression. The protective role of ALOX12-decrease against SCI was verified in LPS-incubated glial cells through repressing inflammatory response and apoptotic formation. Moreover, transgenic mice with ALOX12 over-expression showed accelerated SCI, associated with intensified inflammation and apoptosis. Based on these results, strategies for inhibiting ALOX12 could be used to prevent SCI development by repressing inflammation and apoptosis.

[Nondestructive Analysis of Jingdezhen and Longquan Celadon Wares Excavated from Nanhai No.1 Shipwreck].

The provenance study of ancient ceramics, as an important part in archaeological field, is the researching focus for researchers in scientific and technological archaeology. At present, the provenance study of ancient ceramics mainly depends on chemical analysis technologies while non-destructive physical structural analysis of ceramic glaze is relatively lacking. Therefore, it is difficult to have a comprehensive understanding of ancient ceramics. Optical coherence tomography (OCT) is an emerging non-destructive imaging technology with a high sensitivity. In this paper, the OCT combined with X-ray fluorescence spectroscopy (XRF) is employed firstly to analyze celadon wares of Jingdezhen and Longquan found in Nanhai No.1 shipwreck which is dated to early Southern Song dynasty non-destructively. First, the glaze cross-section structures and decoration characteristics of the celadon wares of the two kilns, Jingdezhen and Longquan,are studied by OCT.The type,thickness of glaze, the glaze inclusions including bubbles, crystals, residual grains, and the cracks on the glaze surface are analyzed based on the OCT images obtained. The characteristics of glaze cross-section structures for the celadon wares of two kilns are compared, and the decoration technologies of the celadon wares are also determined. Next, the chemical compositions of glaze and body of the celadon wares of the two kilns,Jingdezhen and Longquan, are obtained by XRF and compared. Then, the relationship between the differences of glaze cross-section structures and chemical compositions of glaze are discussed. The results show that the celadon wares from Jingdezhen and Longquan are different in glaze cross-section structures, and are the chemical compositions of the glaze and body. Meanwhile the differences of glaze chemical composition are relevant to the differences of glaze cross-section structures. This paper shows that the combination of OCT and XRF is validate as an effective method to identify the porcelains from different kilns.

Role of PGC-1α signaling in skeletal muscle health and disease.

This paper reviews the current understanding of the molecular basis of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α)-mediated pathway and discusses the role of PGC-1α in skeletal muscle atrophy caused by immobilization. PGC-1α is the master transcription regulator that stimulates mitochondrial biogenesis, by upregulating nuclear respiratory factors (NRF-1, 2) and mitochondrial transcription factor A (Tfam), which leads to increased mitochondrial DNA replication and gene transcription. PGC-1α also regulates cellular oxidant-antioxidant homeostasis by stimulating the gene expression of superoxide dismutase-2 (SOD2), catalase, glutathione peroxidase 1 (GPx1), and uncoupling protein (UCP). Recent reports from muscle-specific PGC-1α overexpression underline the importance of PGC-1α in atrophied skeletal muscle, demonstrate enhancement of the PGC-1α mitochondrial biogenic pathway, and reduced oxidative damage. Thus, PGC-1α appears to play a protective role against atrophy-linked skeletal muscle deterioration.

Nuclear translocation of extracellular superoxide dismutase.

Histochemical examination of mouse tissues showed nuclear staining of extracellular superoxide dismutase (EC-SOD), and the nuclear translocation of EC-SOD was also confirmed in cultured cells that had been transfected with its gene, as shown by immunohistochemistry and Western blot analysis. The EC-SOD which was secreted into the medium was incorporated into 3T3-L1 cells and a significant fraction of the material taken up was localized in the nucleus. Site-directed mutagenesis indicated that the heparin-binding domain of EC-SOD functions as the nuclear localization signal. These results suggest that the mechanism of the nuclear transport of EC-SOD involves a series of N-terminal signal peptide- and C-terminal heparin-binding domain-dependent processes of secretion, re-uptake and the subsequent nuclear translocation. The findings herein provide support for the view that the role of EC-SOD is to protect the genome DNA from damage by reactive oxygen species and/or the transcriptional regulation of redox-sensitive gene expression.