Rational Design of a Core-Shell Structured Plasmonic Au@MIL-100(Fe) Nanocomposite for Efficient Photocatalysis.

The utilization of solar light to trigger organic syntheses for the production of value-added chemicals has attracted increasing recent research attention. The integration of plasmonic Au NPs (NPs = nanoparticles) with MOFs would provide a new way for the development of highly efficient photocatalytic systems. In this manuscript, a bottle-around-ship strategy was adopted for the successful synthesis of a core-shell structured Aupvp@MIL-100(Fe) (PVP = polyvinylpyrrolidone) nanocomposite in room temperature. The as-obtained core-shell structured Aupvp@MIL-100(Fe) show improved photocatalytic performance for benzyl alcohol oxidation under visible light, because of the migration of the surface plasmon resonance (SPR) excited hot electrons from plasmonic Au NPs to MIL-100(Fe), resulting in the production of more active O2•- radicals. The removal of the capping agent PVP from Aupvp@MIL-100(Fe) significantly enhanced the photocatalytic performance, because of an improved charge transfer from plasmonic Au NPs to MIL-100(Fe). This study demonstrates an efficient strategy of fabricating superior photocatalytic systems by a rational coupling of plasmonic Au NPs and photocatalytic active MOFs into a core-shell structured nanocomposite.

Tanshinone IIA inhibits cell growth by suppressing SIX1-induced aerobic glycolysis in non-small cell lung cancer cells.

Aerobic glycolysis plays a key role in cancer cell metabolism and contributes to tumorigenesis, including that of non-small cell lung cancer (NSCLC). Tanshinone IIA (Tan IIA), an active compound of Salvia miltiorrhiza, exhibits antitumor properties. Multiple mechanisms are involved in the antitumor action of Tan IIA in lung cancer, such as inhibiting cell growth, promoting cell apoptosis and influencing cellular metabolism. However, the effects of Tan IIA on NSCLC cells and its mechanisms of action remain unclear. The present study shows Tan IIA dose-dependently attenuated the growth of NSCLC cells and in vitro in a dose-dependent manner. Moreover, Tan IIA markedly decreased the ATP level, glucose uptake and lactate production in the NSCLC cells in vitro. Tan IIA also inhibited tumor growth in a xenograft model in vivo. Mechanically, Tan IIA treatment decreased sine oculis homeobox homolog 1 (SIX1) mRNA and protein levels, thus leading to the downregulation of pyruvate kinase isozyme M2, hexokinase 2 and lactate dehydrogenase A (LDHA) expression in A549 cells. SIX1 knockdown with small interfering-RNA inhibited glycolysis in NSCLC cells, suggesting that SIX1 plays a role in the antitumor effect of Tan IIA on NSCLC cells. More importantly, it was demonstrated that SIX1 expression was stimulated in patients with NSCLC and was positively correlated with the LDH serum level. Finally, SIX1 low expression levels predicted the poor prognosis of patients with NSCLC. In conclusion, the present study showed that Tan IIA functioned as an anti-glycolysis agent in NSCLC cells by downregulating SIX1 expression and inhibiting cell proliferation.

Curcumin ameliorates H2O2-induced inflammatory response in chondrocytes by inducing autophagy activation.

Relapsing polychondritis (RP) is a clinical disease characterized by inflammation of cartilage tissue and chondrocytes. The principal curcuminoid curcumin is the most active component in turmeric and has been reported to have a chondroprotective effect, including anti-inflammatory activity, which is vitally important for mitigating RP symptoms and prognosis. However, the mechanisms underlying these actions have remained to be fully elucidated. In the present study, the chondroprotective mechanisms of curcumin on hydrogen peroxide (H2O2)-treated primary chondrocytes were examined in vitro. The viability of chondrocytes treated with H2O2 was significantly reduced in a dose- and time-dependent manner. Cotreatment of curcumin with H2O2 significantly decreased growth inhibition. It was observed that curcumin inhibited the expression levels of the inflammatory mediators interleukin (IL)-1ß, IL-6 and inducible nitric oxide synthase and induced autophagy activation. Curcumin increased the protein levels of the autophagy marker beclin-1 and light chain 3-II and decreased the expression levels of P62 in H2O2-treated chondrocytes. The curcumin-induced anti-inflammatory effects were markedly abrogated by the autophagy inhibitor 3-methyladenine. In conclusion, the present study suggested that curcumin regulates inflammatory factors by activating autophagy in chondrocytes. The protective role of curcumin in chondrocytes was demonstrated, suggesting that it should be explored for the prophylactic treatment of RP in the clinic in the future.

Post-synthetic modifications (PSM) on metal-organic frameworks (MOFs) for visible-light-initiated photocatalysis.

The utilization of green and sustainable solar energy via photocatalysis is regarded as a promising strategy to tackle the ever-increasing energy shortage and environmental deterioration. In addition to traditional semiconductor-based photocatalysts, metal-organic frameworks (MOFs), a class of crystalline micro-mesoporous hybrid materials constructed from metal or metal nodes interconnected with multi-dentate organic linkers, are emerging as a new type of photocatalytic material. Post-synthetic modifications (PSM) on MOFs, in which chemical transformations or exchanges are made on pre-synthesized MOF materials, are found to be a powerful strategy for fabricating photoactive MOFs based on already existing MOFs. In this frontier article, different PSM strategies for the development of photoactive MOFs, including coordination on unsaturated metal sites, metalation on open coordinated sites, covalent modifications on ligands, ligand exchange, metal exchange and cavity encapsulation, have been summarized. Our views on the challenges and the direction in developing photocatalytic MOFs by PSM are also addressed. We hope that this frontier article can provide some guidance for rational designing of highly efficient MOF-based photocatalysts via PSM strategies and to stimulate more research interest to be devoted to this promising yet largely unexplored field.

MOF-253-Supported Ru Complex for Photocatalytic CO2 Reduction by Coupling with Semidehydrogenation of 1,2,3,4-Tetrahydroisoquinoline (THIQ).

MOF-253 (Al(OH)(dcbpy), dcbpy = 2,2'-bipyridine-5,5'-dicarboxylic acid) obtained via a microwave-assisted synthesis was used for the construction of a supported Ru complex containing dcbpy (MOF-253-Ru(dcbpy)2) by coordinating its open N,N'-chelating sites with Ru(II) in Ru(dcbpy)2Cl2. The as-obtained MOF-253-Ru(dcbpy)2 acts as a bifunctional photocatalyst for simultaneous CO2 reduction to produce formic acid and CO, as well as semidehydrogenation of 1,2,3,4-tetrahydroisoquinoline (THIQ) to obtain 3,4-dihydroisoquinoline (DHIQ). The performance over the surface-supported MOF-253-Ru(dcbpy)2 is superior to that over Ru-doped MOF-253 (Ru-MOF-253) obtained via a mix-and-match strategy, indicating that the use of open coordination sites in the MOFs for direct construction of a surface-supported complex is a superior strategy to obtain an MOF-supported homogeneous complex. This study shows the possibility of using an MOF as a platform for the construction of multifunctional heterogeneous photocatalytic systems. The coupling of photocatalytic CO2 reduction with the highly selective dehydrogenation of organics provides an economical and green strategy in photocatalytic CO2 reduction and production of valuable organics simultaneously.

High-sensitivity fiber optic hydrogen sensor in air by optimizing a self-referenced demodulating method.

Self-referenced demodulating methods of fiber optic hydrogen sensors based on WO3-Pd2Pt-Pt composite film are studied in this paper. By employing the proper baseline intensity as sensing parameters, fluctuations of the sensing signal of the hydrogen sensor can be obviously depressed, and sensitivity can be greatly improved. Experimental results show that the resolution of the hydrogen sensor can reach 3 parts per million (ppm) when the hydrogen concentration is lower than 1000 ppm. Additionally, the hydrogen sensor shows better sensitivity toward lower concentrations of hydrogen, enabling a hydrogen threshold down to 10 ppm in air at room temperature. To the best of our knowledge, this is the lowest threshold reported for an optical hydrogen sensor operated at room temperature in air. Moreover, the sensor has good repeatability during hydrogen response. This work proposes a simple and novel method to improve the performance of fiber optic hydrogen sensors, which can greatly promote their potential application in various fields.

Optical Fiber Grating Hydrogen Sensors: A Review.

In terms of hydrogen sensing and detection, optical fiber hydrogen sensors have been a research issue due to their intrinsic safety and good anti-electromagnetic interference. Among these sensors, hydrogen sensors consisting of fiber grating coated with sensitive materials have attracted intensive research interests due to their good reliability and distributed measurements. This review paper mainly focuses on optical fiber hydrogen sensors associated with fiber gratings and various materials. Their configurations and sensing performances proposed by different groups worldwide are reviewed, compared and discussed in this paper. Meanwhile, the challenges for fiber grating hydrogen sensors are also addressed.

Ultra-high sensitive optical fiber hydrogen sensor using self-referenced demodulation method and WO3-Pd2Pt-Pt composite film.

A novel fiber optic hydrogen concentration detection platform with significantly enhanced performance is proposed and demonstrated in this paper. The hydrogen sensing probe was prepared by depositing WO3-Pd2Pt-Pt composite film on the fiber tip of two Bragg gratings paired with high-low reflectivity. At a room temperature of 25°C, the hydrogen sensor has a significant response towards 10 ppm hydrogen in nitrogen atmosphere, and may detect tens of ppb hydrogen changes when the hydrogen concentration is between 10~60 ppm. Besides, the proposed system shows quick response when the hydrogen concentration is above 40 ppm. Moreover, the hydrogen sensor shows good repeatability during the hydrogen response. This work proposes a new concept to develop hydrogen sensing technology with ultra-high sensitivity, which can significantly promote its potential application in various fields, especially for ultra-low hydrogen detection in oxygen-free environment.