Metastable Hexagonal-Phase Nickel with Ultralow Pt Content for an Efficient Alkaline/Seawater Hydrogen Evolution Reaction.

Hydrogen has been hailed as the core of the world's future energy architecture. It is imperative to develop catalysts with an efficient and sustained hydrogen evolution reaction (HER) to scale up alkaline/seawater electrolysis, yet significant difficulties and challenges, such as the high usage of precious metals, still remain. In this paper, a metastable-phase hexagonal close-packed (hcp) Ni-based catalyst with ultralow Pt content (3.1 at %) was designed, which has excellent catalytic performance in the alkaline/seawater HER. The optimal catalyst offers low overpotentials of 21 and 137 mV at 10 mA cm-2 and remains stable during operation for 100 and 300 h at this current density in 1.0 M KOH and real seawater, respectively. A mechanistic study shows that the metastable-phase Ni acts as an anchor site for OH-, which promotes the dissociation of water and greatly improves the formation rate of H2.

Spectrally efficient multi-service fiber-wireless access in low-cost direct-detection THz system at 300†GHz.

This Letter demonstrates a novel, to the best of knowledge, overlapping single-sideband (OSSB) transmission scheme for spectrally efficient multi-service fiber-wireless (FiWi) access in a low-cost direct-detection (DD) THz system. Utilizing the proposed OSSB scheme, user data from different services can share the same spectrum resource yet can be successfully demodulated via one cost-effective DD THz receiver in conjunction with the Kramers-Kronig (KK) based SSB field reconstruction and look-up table (LUT) enabled signal separation algorithms. A proof-of-principle experiment is conducted. Based on an IQ modulator and a single THz zero-bias diode (ZBD), two independent 10-GBd quadrature phase shift keying (QPSK) signals with an overlapped spectrum are successfully demodulated after 20-km fiber and up to 3-m wireless transmission at the 300-GHz band. To the best of our knowledge, this is the first demonstration of multi-service FiWi access with an OSSB format in a 300-GHz DD THz system.

Spin-Polarization Strategy for Enhanced Acidic Oxygen Evolution Activity.

Spin-polarization is known as a promising way to promote the anodic oxygen evolution reaction (OER), since the intermediates and products endow spin-dependent behaviors, yet it is rarely reported for ferromagnetic catalysts toward acidic OER practically used in industry. Herein, the first spin-polarization-mediated strategy is reported to create a net ferromagnetic moment in antiferromagnetic RuO2 via dilute manganese (Mn2+ ) (S = 5/2) doping for enhancing OER activity in acidic electrolyte. Element-selective X-ray magnetic circular dichroism reveals the ferromagnetic coupling between Mn and Ru ions, fulfilling the Goodenough-Kanamori rule. The ferromagnetism behavior at room temperature can be well interpreted by first principles calculations as the interaction between the Mn2+ impurity and Ru ions. Indeed, Mn-RuO2 nanoflakes exhibit a strongly magnetic field enhanced OER activity, with the lowest overpotential of 143 mV at 10 mA cmgeo -2 and negligible activity decay in 480 h stability (vs 200 mV/195 h without magnetic field) as known for magnetic effects in the literature. The intrinsic turnover frequency is also improved to reach 5.5 s-1 at 1.45 VRHE . This work highlights an important avenue of spin-engineering strategy for designing efficient acidic oxygen evolution catalysts.

miR-210 promotes hepatocellular carcinoma progression by modulating macrophage autophagy through PI3K/AKT/mTOR signaling.

BACKGROUND: Tumor-associated macrophages (TAMs) play an important role in tumor development. Increasing research suggests that miR-210 may promote the progression of tumor virulence, but whether its pro-carcinogenic effect in primary hepatocellular carcinoma (HCC) is via an action on M2 macrophages has not been examined. METHODS: Differentiation of THP-1 monocytes into M2-polarized macrophages was induced with phorbol myristate acetate (PMA) and IL-4, IL-13. M2 macrophages were transfected with miR-210 mimics or miR-210 inhibitors. Flow cytometry was used to identify macrophage-related markers and apoptosis levels. The autophagy level of M2 macrophages, expression of PI3K/AKT/mTOR signaling pathway-related mRNAs and protein were detected by qRT-PCR and Western blot. HepG2 and MHCC-97H HCC cell lines were cultured with M2 macrophages conditioned medium to explore the effects of M2 macrophage-derived miR-210 on the proliferation, migration, invasion and apoptosis of HCC cells. RESULTS: qRT-PCR showed increased expression of miR-210 in M2 macrophages. Autophagy-related gene and protein expression was enhanced in M2 macrophages transfected with miR-210 mimics, while apoptosis-related proteins were decreased. MDC staining and transmission electron microscopy observed the accumulation of MDC-labeled vesicles and autophagosomes in M2 macrophages in the miR-210 mimic group. The expression of PI3K/AKT/mTOR signaling pathway in M2 macrophages was reduced in miR-210 mimic group. HCC cells co-cultured with M2 macrophages transfected with miR-210 mimics exhibited enhanced proliferation and invasive ability as compared to the control group, while apoptosis levels were reduced. Moreover, promoting or inhibiting autophagy could enhance or abolish the above observed biological effects, respectively. CONCLUSIONS: miR-210 can promote autophagy of M2 macrophages via PI3K/AKT/mTOR signaling pathway. M2 macrophage-derived miR-210 promotes the malignant progression of HCC via autophagy, suggesting that macrophage autophagy may serve as a new therapeutic target for HCC, and targeting miR-210 may reset the effect of M2 macrophages on HCC.

Metastable Hexagonal Phase SnO2 Nanoribbons with Active Edge Sites for Efficient Hydrogen Peroxide Electrosynthesis in Neutral Media.

Electrochemical two-electron oxygen reduction reaction (2 e- ORR) to produce hydrogen peroxide (H2 O2 ) is a promising alternative to the energetically intensive anthraquinone process. However, there remain challenges in designing 2 e- ORR catalysts that meet the application criteria. Here, we successfully adopt a microwave-assisted mechanochemical-thermal approach to synthesize hexagonal phase SnO2 (h-SnO2 ) nanoribbons with largely exposed edge structures. In 0.1 M Na2 SO4 electrolyte, the h-SnO2 catalysts achieve the excellent H2 O2 selectivity of 99.99 %. Moreover, when employed as the catalyst in flow cell devices, they exhibit a high yield of 3885.26 mmol g-1 h-1 . The enhanced catalytic performance is attributed to the special crystal structure and morphology, resulting in abundantly exposed edge active sites to convert O2 to H2 O2 , which is confirmed by density functional theory calculations.

Homogeneous Metastable Hexagonal Phase Iridium Enhances Hydrogen Evolution Catalysis.

Catalytic reactions are surface-sensitive processes. Fabrication of homogeneous metastable metals can be used to promote phase-dependent catalytic performance; however, this has been a challenging task. Herein, homogeneous metastable hexagonal close-packed (hcp) Ir is epitaxially grown onto metastable phase hcp Ni, as demonstrated using spherical aberration electron microscopy. The as-fabricated metastable hcp Ir exhibits high intrinsic activity for the alkaline hydrogen evolution reaction (HER). In particular, metastable hcp Ir delivers a low overpotential of 17 mV at 10 mA cm-2 and presents a high specific activity of 8.55 mA cm-2 and a high turnover frequency of 38.26 s-1 at -0.07 V versus the reversible hydrogen electrode. Owing to its epitaxially grown structure, metastable hcp Ir is highly stable. Theoretical calculations reveal that metastable hcp Ir promotes H2 O adsorption and fast H2 O dissociation, which contributes to its remarkable HER activity. Findings can elucidate the crystal phase-controlled synthesis of advanced noble metal nanomaterials for the fundamental catalytic applications.

Photonics-aided integrated sensing and communications in mmW bands based on a DC-offset QPSK-encoded LFMCW.

The evolution of mobile communications towards millimeter-wave (mmW) bands provides a strong opportunity for the seamless integration of radar and wireless communications. We present a photonics-aided mmW integrated sensing and communications (ISAC) system constructed by photonic up-conversion using a coherent optical frequency comb, which facilitates zero frequency offset of the resulting mmW signal. The sensing and communications functions are enabled by a joint waveform that encodes a DC-offset QPSK signal on a linear frequency-modulated continuous wave (LFMCW) in baseband. The QPSK encoding ensures the constant envelope of the mmW ISAC signal for long-distance radar detection. The optimized DC offset preserves the distinctive chirp phase and good cross-correlation of the original LFMCW, which can achieve high-resolution sensing by radar de-chirping and assist in communication sequence synchronization by pulse compression, respectively. Experimental results show that the single-user detection with less than 20-mm sensing error and dual-user detection with a 10.4-cm ranging resolution are realized at 28-GHz band, respectively. The wireless communication with a 11.5-Gbit/s transmission rate also at 28-GHz band is successfully tested. Moreover, the proof-of-concept experiments demonstrate the good frequency tunability and wavelength tolerance of the proposed ISAC system.

Compressive Strain in N-Doped Palladium/Amorphous-Cobalt (II) Interface Facilitates Alkaline Hydrogen Evolution.

The development of palladium-based catalysts for alkaline hydrogen evolution reaction (HER) is highly desired for renewable hydrogen energy systems, yet still challenging due to the strong palladium-hydrogen bond. Herein, the bottleneck is largely overcome by constructing a nitridation-induced compressively strained-interface N-doped palladium/amorphous cobalt (II) interface (N-Pd/A-Co(II)), which dramatically boosts HER performance in alkaline condition. The optimized catalyst with the compressive strain of 2.7% exhibits the higher activity with an overpotential of only 58 mV to achieve the current density of 10 mA cm-2 , much better than those of pure Pd (327 mV), and the state-of-art Pt/C (78 mV). Notably, it also shows excellent stability with negligible decline during a 30 h stability test. Detailed analyses reveal that the strong absorption of Hads on Pd can be efficiently reduced via the compressively strained N-doped Pd. And the amorphous Co(II) component accelerates the water dissociation. Consequently, the cooperative effect between the compressed N-doped Pd and amorphous Co(II) creates the impressive HER performance in alkaline condition, highlighting the importance of the functional interface to develop efficient electrocatalysts for HER and beyond.

[Biodegradation of pyridine under UV irradiation].

Pyridine, a complex nitrogen-containing heterocyclic compounds, is usually difficult to degrade by means of single biological method. The internal loop photobiodegradation reactor (ILPBR) was used for degradation of pyridine in batch and continuous experiments following three protocols: photolysis alone (P), biodegradation alone (B), and intimately coupled photolysis and biodegradation (P&B) to investigate the regularity of pyridine degradation. The experimental results indicated that pyridine removal rate by P&B was fastest among three protocols in batch experiment, in which protocol B was faster than P. For initial pyridine concentration of 100 mg L(-1), the pyridine removal rates were respectively 4.95, 10.2 and 14.58 mg (L x h)(-1) corresponding to protocol P, B and P&B. Pyridine degradation kinetic equations were established based on Monod model, and the saturation constants decreased from 1920.4 mg x L(-1) for protocol B to 1094.1 mg x L(-1) for protocol P&B. Protocols P, B and P&B were also used for pyridine degradation in continuous flow and influent pyridine concentration increased from 50 to 300 mg x L(-1), and their average removal rates were respectively 15.8 mg (L x h)(-1) for protocol P, 23.1 mg x (L x h)(-1) for protocol B and 24.9 mg x (L x h)(-1) for protocol P&B, in which the removal rates were higher than that in batch. Experiments suggested that the inhibition of pyridine to biofilm could be relieved due to UV irradiation in process of intimately coupled UV photolysis and biodegradation, and biofilm had kept its bioactivity degrading pyridine and enhanced pyridine removal rates.

2,4,6-trichlorophenol (TCP) photobiodegradation and its effect on community structure.

The mechanisms occurring in a photolytic circulating-bed biofilm reactor (PCBBR) treating 2,4,6-trichlorophenol (TCP) were investigated using batch experiments following three protocols: photodegradation alone (P), biodegradation alone (B), and intimately coupled photodegradation and biodegradation (P&B). Initially, the ceramic particles used as biofilm carriers rapidly adsorbed TCP, particularly in the B experiments. During the first 10 min, the TCP removal rate for P&B was equal to the sum of the rates for P and B, and P&B continued to have the greatest TCP removal, with the TCP concentration approaching zero only in the P&B experiments. When phenol, an easily biodegradable compound, was added along with TCP in order to promote TCP mineralization by means of secondary utilization, P&B was superior to P and B in terms of mineralization of TCP, giving 95% removal of chemical oxygen demand (COD). The microbial communities, examined by clone libraries, changed dramatically during the P&B experiments. Whereas Burkholderia xenovorans, a known degrader of chlorinated aromatics, was the dominant strain in the TCP-acclimated inoculum, it was replaced in the P&B biofilm by strains noted for biofilm formation and biodegrading non-chlorinated aromatics.