Core-Shell Structured MXene@Carbon Nanodots as Bifunctional Catalysts for Solar-Assisted Water Splitting.

The design of nonprecious bifunctional electrocatalysts with high activity and prolonged durability in a wide pH range is essential for the development of the highly efficient, cost-effective, and simplified overall water splitting systems. Here, we report core-shell structured MXene@carbon (MX@C) nanodot hybrids with high bifunctional activity, where N-doped carbon shells are grown in a heteroepitaxial manner strongly interacting with the MXene core. The resulting MX@C nanodot hybrids show enhanced catalytic activity for electrochemical hydrogen evolution reaction (HER) in various pH media from 0 to 14. At pH 14, MX@C achieves the low onset potential of 134 mV at 10 mA/cm2 and reduced Tafel slope of 32 mV/dec due to the facilitated charge transfer along the recombination reaction. For the oxygen evolution reaction (OER), MX@C nanodots are incorporated onto the surface of molybdenum-doped bismuth vanadate (Mo:BiVO4) as a cocatalyst of the photoanode, thereby achieving 1.5 times higher photocurrent density than pristine Mo:BiVO4 at 1.23 V (vs reversible hydrogen electrode) due to the enhanced light absorption and charge transfer efficiency. The superiority of this hybrid catalyst is demonstrated implementing the solar-assisted overall water splitting cells based on the MX@C cathode and MX@C/Mo:BiVO4 photoanode. These cells show the enhancement of current density from 0.78 to 1.23 mA/cm2 with long-term durability over 8 h. These results are attributed to the facile surface catalytic kinetics of the chemically and electronically coupled MX@C hybrid at the heterointerface for both OER and HER.

Two-Dimensional Metallic Niobium Diselenide for Sub-micrometer-Thin Antennas in Wireless Communication Systems.

The state-of-the-art of the Internet of things (IoT) and smart electronics demands advances in thin and flexible radio frequency (RF) antennas for wireless communication systems. So far, nanostructured materials such as metals, carbon nanotubes, graphene, MXene, and conducting polymers have been investigated due to their noteworthy electrical conductivity. However, most antennas based on metallic materials are thick, which limits their application in miniaturized and portable electronic devices. Herein, we report two-dimensional (2D) metallic niobium diselenide (NbSe2) for a monopole patch RF antenna, which functions effectively despite its sub-micrometer thickness, which is less than the skin depths of other metals. The as-fabricated antenna has an 855 nm thickness and a 1.2 Ω sq-1 sheet resistance and achieves a reflection coefficient of -46.5 dB, a radiation efficiency of 70.6%, and omnidirectional RF propagation. Additionally, the resonance frequency of this antenna at the same thickness is reconfigured from 2.01 to 2.80 GHz, while decreasing its length and preserving its reflection coefficient of less than -10 dB. This approach offers a facile process to synthesize 2D metallic transition metal dichalcogenides for the rational design of flexible, miniaturized, frequency-tunable, and omnidirectional monopole patch RF antennas for body-centric wearable communication systems.

High Expression of Angiopoietin-1 is Associated with Lymph Node Metastasis and Invasiveness of Papillary Thyroid Carcinoma.

BACKGROUND: We investigated the expression of angiopoietins in patients with papillary thyroid carcinoma (PTC) and the role of angiopoietins as biomarkers predicting the aggressiveness of PTC. METHODS: Expression of angiopoietins was evaluated by immunohistochemistry of tumor specimens from patients with PTC. We demonstrated potential correlations between expression of angiopoietins and clinicopathologic features. RESULTS: High expression of Ang-1 was positively correlated with a tumor size >1 cm, capsular invasion, extrathyroid extension, lymphovascular invasion, lymph node metastasis, and recurrence (P < 0.05). Moreover, multivariate analysis revealed that high expression of Ang-1 was an independent risk factor for lymph node metastasis (P < 0.001, odds ratio [OR] = 62.113) and lymphovascular invasion (P = 0.027, OR 4.405). However, there was no significant correlation between Ang-2 and clinicopathologic features. CONCLUSIONS: Our results suggest that Ang-1 can serve as a valuable prognostic biomarker for lymph node metastasis and invasiveness in patients with PTC.

EZH2 is associated with poor prognosis in head-and-neck squamous cell carcinoma via regulating the epithelial-to-mesenchymal transition and chemosensitivity.

OBJECTIVES: Increasing evidence suggests that epigenetic regulation is responsible for tumor initiation and progression in head and neck squamous cell carcinoma (HNSCC). Although the polycomb group protein enhancer zeste homolog 2 (EZH2) is upregulated and a key epigenetic modifier implicated in various cancers, its molecular mechanism in HNSCC remains unknown. Herein, we investigated the role of EZH2 in HNSCC progression and its clinical implication as an HNSCC risk predictor. MATERIALS AND METHOD: A retrospective analysis was performed on 90 HNSCC patients who had curative surgery between 1999 and 2011. Patients with high and low EZH2 expression were compared by the various clinicopathological factors. Survival rates were estimated by the Kaplan-Meier method and log-rank test was used to determine significance. For functional in vitro analysis, migration/invasion assay and Western blotting were performed after EZH2 knockdown using siRNA. In addition, cell proliferation was measured to clarify the role of EZH2 on cisplatin chemotherapy. RESULTS: In patients with HNSCC, high EZH2 expression was correlated with advanced T stage and poor survival outcome. RNAi analysis revealed that EZH2 silencing increased E-cadherin expression while decreasing that of N-cadherin and Vimentin without altering Snail/Slug signaling, which led to decreased cell migration/invasion. EZH2 is also associated with tumor aggressiveness via regulating the epithelial-to-mesenchymal transition. Furthermore, we show that high EZH2 expression decreases sensitivity to cisplatin-based chemotherapy. CONCLUSION: Our results indicate that EZH2 may not be only a predictive and prognostic biomarker but also a potential personalized therapeutic target for the treatment of HNSCC.