Mechanism of indoleamine 2, 3-dioxygenase inhibiting cardiac allograft rejection in mice

Indoleamine 2, 3-dioxygenase (IDO)-mediated regulation of tryptophan metabolism plays an important role in immune tolerance in transplantation, but it has not been elucidated which mechanism specifically induces the occurrence of immune tolerance. Our study revealed that IDO exerts immunosuppressive effects through two pathways in mouse heart transplantation, ‘tryptophan depletion’ and ‘tryptophan metabolite accumulation’. The synergism between IDO⁺DC and TC (tryptophan catabolic products) has stronger inhibitory effects on T lymphocyte proliferation and mouse heart transplant rejection than the two intervention factors alone, and significantly prolong the survival time of donor-derived transplanted skin. This work demonstrates that the combination of IDO⁺DC and TC can induce immune tolerance to a greater extent, and reduce the rejection of transplanted organs.     

Ellagic acid protects dopamine neurons from rotenone‐induced neurotoxicity via activation of Nrf2 signalling

Parkinson's disease (PD) is the second most prevalent central nervous system (CNS) degenerative disease. Oxidative stress is one of key contributors to PD. Nuclear factor erythroid‐2‐related factor 2 (Nrf2) is considered to be a master regulator of many genes involved in anti‐oxidant stress to attenuate cell death. Therefore, activation of Nrf2 signalling provides an effective avenue to treat PD. Ellagic acid (EA), a natural polyphenolic contained in fruits and nuts, possesses amounts of pharmacological activities, such as anti‐oxidant stress and anti‐inflammation. Recent studies have confirmed EA could be used as a neuroprotective agent in neurodegenerative diseases. Here, mice subcutaneous injection of rotenone (ROT)‐induced DA neuronal damage was performed to investigate EA‐mediated neuroprotection. In addition, adult Nrf2 knockout mice and different cell cultures including MN9D‐enciched, MN9D‐BV‐2 and MN9D‐C6 cell co‐cultures were applied to explore the underlying mechanisms. Results demonstrated EA conferred neuroprotection against ROT‐induced DA neurotoxicity. Activation of Nrf2 signalling was involved in EA‐mediated DA neuroprotection, as evidenced by the following observations. First, EA activated Nrf2 signalling in ROT‐induced DA neuronal damage. Second, EA generated neuroprotection with the presence of astroglia and silence of Nrf2 in astroglia abolished EA‐mediated neuroprotection. Third, EA failed to produce DA neuroprotection in Nrf2 knockout mice. In conclusion, this study identified EA protected against DA neuronal loss via an Nrf2‐dependent manner.     

In Vitro Effects of Ginseng and the Seed of Zizyphus jujuba var. spinosa on Gut Microbiota of Rats with Spleen Deficiency

Ginseng and the seed of Zizyphus jujuba var. spinosa, which are traditional Chinese medicinal materials, were often used in ancient Chinese recipes as a pair of medicines. They can replenish the primordial qi and tonify the spleen. This study investigated the effects of ginseng and the seed of Zizyphus jujuba var. spinosa (GS) extract on gut microbiota diversity in rats with spleen deficiency syndrome (SDS). A total of 52 compounds (including 16 flavonoids, 35 saponins, and 1 alkaloid) were identified and analyzed from the GS extract by UPLC‐Q‐Orbitrap‐MS/MS. The GS extract significantly increased the relative abundance of Firmicutes and Bacteroidetes in rats with SDS but decreased that of Proteobacteria and Actinobacteria. At the genus level, the GS extract significantly increased the relative abundance of Lactobacillus and Bifidobacterium in rats with SDS but decreased that of Streptococcus, Escherichia‐Shigella, Veillonella, and Enterococcus. In addition, the GS extract influenced glucose and amino acid metabolism. In summary, the results showed that the GS extract changed the structure and diversity of gut microbiota in rats with SDS and balanced the metabolic process.     

The Rise of Textured Perovskite Morphology: Revolutionizing the Pathway toward High‐Performance Optoelectronic Devices

Halide perovskite materials have achieved overwhelming success in various optoelectronic applications, especially perovskite solar cells and perovskite‐based light‐emitting diodes (P‐LEDs), owing to their outstanding optical and electric properties. It is widely believed that flat and mirror‐like perovskite films are imperative for achieving high device performance, while the potential of other perovskite morphologies, such as the emerging textured perovskite, is overlooked, which leaves plenty of room for further breakthroughs. Compared to flat and mirror‐like perovskites, textured perovskites with unique structures, e.g., coral‐like, maze‐like, column‐like or quasi‐core@shell assemblies, are more efficient at light harvesting and charge extraction, thus revolutionizing the pathways toward ultrahigh performance in perovskite‐based optoelectronic devices. Employing a textured perovskite morphology, the record of external quantum efficiency for P‐LEDs is demonstrated as 21.6%. In this research news, recent progress in the utilization of textured perovskite is summarized, with the emphasis on the preparation strategies and prominent optoelectronic properties. The impact of the textured morphology on light harvesting, carrier dynamic management, and device performance is highlighted. Finally, the challenges and great potential of employing these innovative morphologies in fabricating more efficient optoelectronic devices, or creating a new energy harvesting and conversion regime are also provided.     

High‐Performance Platinum‐Perovskite Composite Bifunctional Oxygen Electrocatalyst for Rechargeable Zn–Air Battery

Constructing highly active electrocatalysts with superior stability at low cost is a must, and vital for the large‐scale application of rechargeable Zn–air batteries. Herein, a series of bifunctional composites with excellent electrochemical activity and durability based on platinum with the perovskite Sr(Co_0.8Fe_0.2)_0.95P_0.05O_3?δ (SCFP) are synthesized via a facile but effective strategy. The optimal sample Pt‐SCFP/C‐12 exhibits outstanding bifunctional activity for the oxygen reduction reaction and oxygen evolution reaction with a potential difference of 0.73 V. Remarkably, the Zn–air battery based on this catalyst shows an initial discharge and charge potential of 1.25 and 2.02 V at 5 mA cm^?2, accompanied by an excellent cycling stability. X‐ray photoelectron spectroscopy, X‐ray absorption near‐edge structure, and extended X‐ray absorption fine structure experiments demonstrate that the superior performance is due to the strong electronic interaction between Pt and SCFP that arises as a result of the rapid electron transfer via the Pt? O? Co bonds as well as the higher concentration of surface oxygen vacancies. Meanwhile, the spillover effect between Pt and SCFP also can increase more active sites via lowering energy barrier and change the rate‐determining step on the catalysts surface. Undoubtedly, this work provides an efficient approach for developing low‐cost and highly active catalysts for wider application of electrochemical energy devices.     

Direct Recycling of Spent NCM Cathodes through Ionothermal Lithiation

Ionic liquids (ILs) are a family of nonconventional molten salts that offer many advantages, such as negligible vapor pressures, negligible flammability, wide liquidus ranges, good thermal stability, and much synthesis flexibility. The unique solvation environment of these ILs provides new reaction or flux media for controlling formation of solid‐state materials with a minimum perturbation of morphologies. A successful lithiation via ionothermal synthesis using a cost‐effective Li halide as Li source and recyclable ILs as solvents is reported here for the direct recycling of LiNi_1/3Co_1/3Mn_1/3O₂ (NCM 111) cathodes. In addition, the ionic liquids can be readily recycled and reused after ionothermal lithiation. The lithiation of spent cathodes can enable the direct recycling of spent cathode materials in lithium‐ion batteries.     

Oxygen‐Deficient Blue TiO2 for Ultrastable and Fast Lithium Storage

Developing a titanium dioxide (TiO₂)‐based anode with superior high‐rate capability and long‐term cycling stability is important for efficient energy storage. Herein, a simple one‐step approach for fabricating blue TiO₂ nanoparticles with oxygen vacancies is reported. Oxygen vacancies can enlarge lattice spaces, lower charge transfer resistance, and provide more active sites in TiO₂ lattices. As a result, this blue TiO₂ electrode exhibits a highly reversible capacity of 50 mAh g^?1 at 100 C (16 800 mA g^?1) even after 10 000 cycles, which is attributable to the combination of surface capacitive process and remarkable diffusion‐controlled insertion revealed by the kinetic analysis. The strategy of employing oxygen‐deficient nanoparticles may be extended to the design of other robust semiconductor materials as electrodes for energy storage.