Directed Electron Delivery from a Pb-Free Halide Perovskite to a Co(II) Molecular Catalyst Boosts CO2 Photoreduction Coupled with Water Oxidation.

The development of high-performance photocatalytic systems for CO2 reduction is appealing to address energy and environmental issues, while it is challenging to avoid using toxic metals and organic sacrificial reagents. We here immobilize a family of cobalt phthalocyanine catalysts on Pb-free halide perovskite Cs2AgBiBr6 nanosheets with delicate control on the anchors of the cobalt catalysts. Among them, the molecular hybrid photocatalyst assembled by carboxyl anchors achieves the optimal performance with an electron consumption rate of 300±13 µmol g-1 h-1 for visible-light-driven CO2-to-CO conversion coupled with water oxidation to O2, over 8 times of the unmodified Cs2AgBiBr6 (36±8 µmol g-1 h-1), also far surpassing the documented systems (<150 µmol g-1 h-1). Besides the improved intrinsic activity, electrochemical, computational, ex-/in situ X-ray photoelectron and X-ray absorption spectroscopic results indicate that the electrons photogenerated at the Bi atoms of Cs2AgBiBr6 can be directionally transferred to the cobalt catalyst via the carboxyl anchors which strongly bind to the Bi atoms, substantially facilitating the interfacial electron transfer kinetics and thereby the photocatalysis.

Nanoscale Janus Z-Scheme Heterojunction for Boosting Artificial Photosynthesis.

Artificial photosynthesis for CO2 reduction coupled with water oxidation currently suffers from low efficiency due to inadequate interfacial charge separation of conventional Z-scheme heterojunctions. Herein, an unprecedented nanoscale Janus Z-scheme heterojunction of CsPbBr3 /TiOx is constructed for photocatalytic CO2 reduction. Benefitting from the short carrier transport distance and direct contact interface, CsPbBr3 /TiOx exhibits significantly accelerated interfacial charge transfer between CsPbBr3 and TiOx (8.90 × 108 s-1 ) compared with CsPbBr3 :TiOx counterpart (4.87 × 107 s-1 ) prepared by traditional electrostatic self-assembling. The electron consumption rate of cobalt doped CsPbBr3 /TiOx can reach as high as 405.2 ± 5.6 µmol g-1 h-1 for photocatalytic CO2 reduction to CO coupled with H2 O oxidation to O2 under AM1.5 sunlight (100 mW cm-2 ), over 11-fold higher than that of CsPbBr3 :TiOx , and surpassing the reported halide-perovskite-based photocatalysts under similar conditions. This work provides a novel strategy to boost charge transfer of photocatalysts for enhancing the performance of artificial photosynthesis.

Oridonin employs interleukin 1 receptor type 2 to treat noise-induced hearing loss by blocking inner ear inflammation.

NOD-like receptor protein 3 (NLRP3) inflammasomes trigger the inflammatory cascades and participate in various inflammatory diseases, including noise-induced hearing loss (NIHL) caused by oxidative stress. Recently, the anti-inflammatory traditional medicine oridonin (Ori) has been reported to provide hearing protection in mice after noise exposure by blocking the NLRP3-never in mitosis gene A-related kinase 7 (NEK7)-inflammasome complex assembly. Using RNA sequencing analysis, we further elucidated that interleukin 1 receptor type 2 (IL1R2) may be another crucial factor regulated by Ori to protect NIHL. We observed that IL1R2 expression was localized in spiral ganglion neurons, inner and outer hair cells, in Ori-treated mouse cochleae. Additionally, we confirmed that ectopic overexpression of IL1R2 in the inner ears of healthy mice using an adeno-associated virus delivery system significantly reduced noise-induced ribbon synapse lesions and hearing loss by blocking the "cytokine storm" in the inner ear. This study provides a novel theoretical foundation for guiding the clinical treatment of NIHL.

Encapsulating Perovskite Quantum Dots in Iron-Based Metal-Organic Frameworks (MOFs) for Efficient Photocatalytic CO2 Reduction.

Improving the stability of lead halide perovskite quantum dots (QDs) in a system containing water is the key for their practical application in artificial photosynthesis. Herein, we encapsulate low-cost CH3 NH3 PbI3 (MAPbI3 ) perovskite QDs in the pores of earth-abundant Fe-porphyrin based metal organic framework (MOF) PCN-221(Fex ) by a sequential deposition route, to construct a series of composite photocatalysts of MAPbI3 @PCN-221(Fex ) (x=0-1). Protected by the MOF the composite photocatalysts exhibit much improved stability in reaction systems containing water. The close contact of QDs to the Fe catalytic site in the MOF, allows the photogenerated electrons in the QDs to transfer rapidly the Fe catalytic sites to enhance the photocatalytic activity for CO2 reduction. Using water as an electron source, MAPbI3 @PCN-221(Fe0.2 ) exhibits a record-high total yield of 1559 µmol g-1 for photocatalytic CO2 reduction to CO (34 %) and CH4 (66 %), 38 times higher than that of PCN-221(Fe0.2 ) in the absence of perovskite QDs.

Engineering a CsPbBr3-based nanocomposite for efficient photocatalytic CO2 reduction: improved charge separation concomitant with increased activity sites.

Metal-halide perovskite nanocrystals have emerged as one of the promising photocatalysts in the photocatalysis field owing to their low-cost and excellent optoelectronic properties. However, this type of nanocrystals generally displays low activity in photocatalytic CO2 reduction owing to the lack of intrinsic catalytic sites and insufficient charge separation. Herein, we functionalized CsPbBr3 nanocrystals with graphitic carbon nitride, containing titanium-oxide species (TiO-CN) to develop an efficient composite catalyst system for photocatalytic CO2 reduction using water as the electron source. Compared to its congener with pristine CsPbBr3, the introduction of TiO-CN could not only increase the number of active sites, but also led to a swift interfacial charge separation between CsPbBr3 and TiO-CN due to their favorable energy-offsets and strong chemical bonding behaviors, which endowed this composite system with an obviously enhanced photocatalytic activity in the reduction of CO2 to CO with water as the sacrificial reductant. Over 3-fold and 6-fold higher activities than those of pristine CsPbBr3 nanocrystals and TiO-CN nanosheets, respectively, were observed under visible light irradiation. Our study provides an effective strategy for improving the photocatalytic activity of metal-halide perovskite nanocrystals, thus promoting their photocatalytic application in the field of artificial photosynthesis.

Up-regulation of interleukin-22 mediates liver fibrosis via activating hepatic stellate cells in patients with hepatitis C.

Interleukin-22 (IL-22) is known to play a critical role in liver immunity. However, the role of IL-22 in HCV-associated liver fibrosis is poorly understood. In this study, patients with HCV infection disclosed significant increases in peripheral numbers of IL-22-producing cells as well as in IL-22 plasma levels. In the liver, the increased intrahepatic IL-22(+) cells were positively correlated with fibrotic staging scores and clinical progression from CHC to cirrhosis. Moreover, the majority of IL-22(+) cells were located in fibrotic areas in the liver of patients with cirrhosis and co-localized with α-smooth muscle actin (α-SMA) positive hepatic stellate cells (HSCs). In vitro, administration of IL-22 was accompanied with inhibited LX-2 cell apoptosis, promoted LX-2 cell proliferation, increased expression of α-SMA, and up-regulated collagen production by LX-2 cells. Collectively, our data provide evidence that IL-22 may contribute to the fibrogenesis of HCV-associated liver fibrosis by activating HSCs.

Diffusion-weighted MR imaging for detection of extrahepatic cholangiocarcinoma.

OBJECTIVES: To measure the sensitivity of diffusion-weighted imaging (DWI) and determine the most appropriate b value for DWI; to explore the correlation between the apparent diffusion coefficient (ADC) value and the degree of extrahepatic cholangiocarcinoma differentiation. METHODS: Preoperative diffusion-weighted imaging and magnetic resonance examinations were performed for 31 patients with extrahepatic cholangiocarcinoma. Tumor ADC values were measured, and the signal-to-noise ratio, contrast-to-noise ratio, and signal-intensity ratio between the diffusion-weighted images with various b values as well as the T2-weighted images were calculated. Pathologically confirmed patients were pathologically graded to compare the ADC value with different b values of tumor at different degrees of differentiation, and the results were statistically analyzed by using the Friedman test. RESULTS: A total of 29 cases of extrahepatic cholangiocarcinoma were detected by DWI. As the b value increased, tumor signal-to-noise ratio and contrast-to-noise ratio between the tumor and normal liver gradually decreased, but the tumor signal-intensity ratio gradually increased. When b=800 s/mm2, contrast-to-noise ratio between tumor and normal liver, tumor signal-intensity ratio, and tumor signal-to-noise ratio of diffusion-weighted images were all higher than those of T2-weighted images; the differences were statistically significant (P<0.05). As the b value increased, the tumor ADC value gradually declined. As the degree of differentiation decreased, the tumor ADC value declined. CONCLUSION: The b value of 800 s/mm2 was the best in DWI of extrahepatic cholangiocarcinoma; the lesion ADC value declined as the degree of cancerous tissue differentiation decreased.

[Effects of clearance of superoxide anion by catechin on the expression of NO and eNOS and apoptosis in endothelial progenitor cells induced by angiotensin II].

OBJECTIVE: To evaluate the effect of clearance of superoxide anion by catechin on the expression of nitrogen monoxidum (NO) and endothelial nitricoxide synthase (eNOS) and apoptosis in endothelial progenitor cells (EPCs) induced by angiotensin II (Ang II). METHODS: The marrow endothelial progenitor cells of Sprague-Dawley rats were isolated and assigned to control (no treatment), Ang II treatment and Ang II + catechin treatment groups. After 48 hrs of culture, the concentration of O2*- in the supernate was measured by the NBT method, and NO concentration in the supernate was measured by the nitrate reductase method; the apoptosis rate of EPCs was detected by the TUNEL method; the mRNA expression of eNOS was detected by RT-PCR; the protein expression of eNOS was detected by Western blot analysis. RESULTS: Ang II of 10-6 mol/L was determined as the suitable concentration for cell induction by the MTT test. Catechin of 400 mg/L was determined as an advisable intervention dosage. The apoptosis rate of EPCs in the control, the Ang II and the Ang II+catechin treatment groups were 2.48+/-0.12%, 54.18+/-0.77% and 16.87+/-0.35%, respectively, and there were significant differences among the three groups (P<0.01). The O2*- concentration in the Ang II and the Ang II+catechin treatment groups (81.7+/- 3.6 and 62.3+/- 2.2 U/L respectively) was significantly higher than that in the control group (33.7+/- 2.8 U/L) (P<0.01). An increased NO concentration was also found in the Ang II (189. 8+/- 9.0 micromol/L) and the Ang II+catechin treatment groups (276.4+/- 10.1 micromol/L) compared with that in the control group (105.8+/- 9.8 micromol/L) (P<0.01). There were significant differences in the concentrations of O2*- and NO between the Ang II and the Ang II+catechin treatment groups (P<0.05). The mRNA (P<0.05) and protein expression (P<0.01) of eNOS in the Ang II and the Ang II+catechin treatment groups increased significantly compared with those in the control group. The Ang II+catechin treatment group showed increased eNOS protein expression compared with the Ang II group (P<0.05). CONCLUSIONS: Ang II may induce the generation of O2*-, inactivate NO and increase gene and protein expression of eNOS in EPCs. Catechin might decrease the apoptosis of EPCs through the effective clearance of O2*-and the reduction of NO inactivation and of eNOS protein uncoupling.