Hydrogen Storage Capacity of Cobalt Cluster Ions.

The adsorption of H2 on gas-phase Con± (n = 5-12) clusters at 300 K and the desorption of H2 from ConHm± upon heating were studied experimentally by combining thermal desorption spectrometry and mass spectrometry to elucidate the hydrogen storage property of the Co clusters. Hydrogen atoms adsorbed well on Con+ (n = 5, 10-12) and Con- (n = 5-12) at 300 K to form ConHm±. The atomic ratios, m/n, for ConHm- (0.9-1.4) were higher than those for ConHm+ (0.2-1.1). According to density functional theory (DFT) calculations, the first few H2 molecules had a tendency to dissociatively adsorb onto the Co clusters. Further, the bonding nature of the H atoms was ionic, similar to the H atoms in the metallic hydrides. In contrast, H2, adsorbed molecularly, was explained in terms of σ complex formation. H2 molecules were desorbed from the clusters upon heating. The temperature dependences showed that ConHm- released H2 at a higher temperature (700-800 K) than ConHm+ (600-700 K), suggesting that Con- should have a higher affinity to hydrogen than Con+. The desorption temperatures were lower than those of VnHm+, which was consistent with the fact that the adsorption energies of H2 were lower for the Co clusters than those for the V clusters. The low adsorption energies were ascribed to their large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps in the Co clusters.

Rapid Formation of Epitaxial Oxygen Evolution Reaction Catalysts on Dendrites with High Catalytic Activity and Stability.

Oxygen evolution reaction is an essential but kinetically sluggish step in many energy storage and conversion processes and therefore is in pursuit of highly efficient and stable catalysts. Although nanosized transition-metal-based oxides/hydroxides exhibit high catalytic activity toward the oxygen evolution reaction (OER), many of them suffer from low stability at an anode current density in industrial scale. Herein, by combining a rapid epitaxial formation method with dynamic bubble-templated electrodeposition, we successfully developed single crystalline NiFeCu oxide catalysts with a hierarchical porous structure. It was found that the structure can facilitate fast electron transportation for the catalysts and retard the diffusion of the O atoms to the inner metallic current collector. The hierarchical pores inherited from the hydrogen bubble templates built ideal channels for the massive and rapid release of oxygen bubbles. As a consequence, the NiFeCu oxides catalyzed the OER more efficiently and steadily than the commercial RuO2 catalyst at an anode current density in industrial scale (300 mA/cm2). This work, by resolving the durability concerns for nanosized oxides, offers a series of highly efficient and stable catalysts for OER and a structure building strategy to boost the catalytic activity and stability for nonconductive catalysts.

Hydrogen Storage Mechanism by Gas-Phase Vanadium Cluster Cations Revealed by Thermal Desorption Spectrometry.

The adsorption of hydrogen on gas-phase vanadium cluster cations, Vn+ (n = 3-14), at 300 K and desorption of hydrogen from hydride clusters, VnHm+, upon heating were observed experimentally by combined thermal desorption spectrometry and mass spectrometry analyses. The ratio m/n was approximately 1.3 for all n values at 300 K, which was reduced to approximately zero at 1000 K. For n = 4, stable cluster geometries of V4Hm+ (m = 0, 2, 4, and 6) were investigated by DFT calculations, revealing that V4 adopted a trigonal pyramidal structure and the H atoms adsorbed mainly on the µ2 bridge sites. The adsorption reaction pathway of one H2 molecule on V4+ was also investigated. The experimentally estimated desorption energies of the H2 molecules were consistent with their calculated binding energies. Among the observed hydride clusters, V6H8+ was found to be significantly thermally durable, probably because of its close-packed octahedral V6 core structure, with H atoms occupying all hollow sites.

KHSRP modulated cell proliferation and cell cycle via regulating PPP2CA and p27 expression in Wilms tumor.

Wilms tumor (WT) is the most common renal malignancy in children, and the survival rate of high-risk WT patients was still low despite multimodality therapy. KHSRP, an RNA-binding protein, has been proved to be relative to tumor progression in different kinds of malignancies, but the function of KHSRP in WT remained unclear. Here, our study aimed to explore and clarify the function of KHSRP in WT cells and its molecular mechanism. Thus, our results showed that KHSRP was highly expressed in WT tumor tissues compared to normal kidney tissues and correlated with poor prognosis in WT patients. Downregulation of KHSRP using siRNAs in WT cell line SK-NEP-1 and Wit49 resulted in inhibition of cell proliferation and cell cycle arrest via stabilizing and upregulating p27 protein. Furthermore, mechanistic analyses revealed that KHSRP bound to 3'UTR of PPP2CA mRNA and modulating its mRNA stability, resulting in regulation of the phosphorylation level and protein stability of p27 in WT cell lines. In conclusion, our results demonstrated that KHSRP played an important role in WT and modulated cell proliferation and cell cycle via regulating the expression of PPP2CA and p27.

Pan­cancer analyses reveal the regulation and clinical outcome association of PCLAF in human tumors.

Studies have shown that PCNA clamp associated factor (PCLAF) plays a paramount role in a variety of cancers; however, the expression profile and the specific molecular mechanism of PCLAF in cancer remains unclear, as is its value in the human pan­cancer analysis. Based on the publicly available datasets of The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), a comprehensive analysis of the probable carcinogenic effects of the PCLAF gene was performed in 33 human cancers. It was found that PCLAF is highly expressed in cancer tissues compared with normal tissues, and is significantly correlated with poor prognosis. We found that the eight tumors with significantly high PCLAF expression presented with decreased DNA methylation levels of PCLAF, including cholangiocarcinoma (CHOL), cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC), glioblastoma multiforme (GBM), pheochromocytoma and paraganglioma (PCPG), sarcoma (SARC), testicular germ cell tumor (TGCT), stomach adenocarcinoma (STAD), and uterine corpus endometrial carcinoma (UCEC). The expression of PCLAF was found to be positively correlated with activated CD4 T cells (Act CD4) and type 2 T helper (Th2) cells, suggesting that PCLAF may play a particular role in tumor immune infiltration. In addition, the functional mechanism of PCLAF also involves the mitotic cell cycle process, cell division, and DNA replication. Our first pan­cancer study provides a relatively extensive understanding of the carcinogenic effects of PCLAF in miscellaneous tumors.

Lactobacillus fermentum HFY06 attenuates D-galactose-induced oxidative stress and inflammation in male Kunming mice.

There has been considerable research on oxidative stress and inflammation, and their relationship with degenerative diseases. This study investigated the effect of Lactobacillus fermentum HFY06 on aging mice induced by D-galactose. The results showed that L. fermentum HFY06 inhibited the atrophy of the brain, kidneys, liver, and spleen, increased serum SOD, GSH, CAT, and MDA, and decreased IL-6, IL-1ß, TNF-α, and IFN-γ. Quantitative PCR showed that L. fermentum HFY06 upregulated the expression of Nrf2, γ-GCS, NOS1, NOS3, SOD1, SOD2, and CAT in the liver and brain tissues, but decreased the expression of NOS2. Western blot analysis showed that L. fermentum HFY06 effectively upregulated the protein expression of SOD1, SOD2, and CAT in the livers and brains of mice. These results suggest that L. fermentum HFY06 can effectively alleviate D-galactose-induced aging in mice, and may activate the Nrf2 signaling pathway and increase the levels of downstream regulatory inflammatory factors and antioxidant enzymes. In conclusion, consumption of L. fermentum HFY06 may prevent aging or reduce oxidative stress.