Autophagy Is a Protective Response to the Oxidative Damage to Endplate Chondrocytes in Intervertebral Disc: Implications for the Treatment of Degenerative Lumbar Disc

Low back pain (LBP) is the leading cause of disability in the elderly. Intervertebral disc degeneration (IDD) was considered as the main cause for LBP. Degeneration of cartilaginous endplate was a crucial harmful factor during the initiation and development of IDD. Oxidative stress was implicated in IDD. However, the underlying molecular mechanism for the degeneration of cartilaginous endplate remains elusive. Herein, we found that oxidative stress could induce apoptosis and autophagy in endplate chondrocytes evidenced by western blot analysis, flow cytometry, immunofluorescence staining, GFP-LC3B transfection, and MDC staining. In addition, we also found that the apoptosis of endplate chondrocytes was significantly increased after the inhibition of autophagy by bafilomycin A1 shown by flow cytometry. Furthermore, mTOR pathway upstream autophagy was greatly suppressed suggested by western blot assay. In conclusion, our study strongly revealed that oxidative stress could increase autophagy and apoptosis of endplate chondrocytes in intervertebral disc. The increase of autophagy activity could prevent endplate chondrocytes from apoptosis. The autophagy in endplate chondrocytes induced by oxidative stress was mTOR dependent. These findings might shed some new lights on the mechanism for IDD and provide new strategies for the treatments of IDD

Legumes in Chinese Natural Grasslands: Species, Biomass, and Distribution

The composition and abundance of legumes affect the economic value and ecological sustainability of natural grasslands. We collected data on species richness and aboveground biomass of legumes and their percentages of the total community at 78 field sites in Chinese natural grasslands on the Tibetan Plateau (alpine steppe and alpine meadow) and in Inner Mongolia (meadow steppe, typical steppe, and desert steppe), and analyzed the association between these attributes with community, climate, and soil factors. At least one legume species occurred in 89.7% of the sites studied; the genera Astragalus, Oxytropis, and Medicago were dominant among the 12 legume genera recorded. Generally, within 1 m2 of grassland, only one legume species was present with an aboveground biomass of 1.1 g; this accounted for 9.1% of community species richness and 1.7% of total aboveground biomass. In comparison with many other types of grassland around the world, both the legume aboveground biomass and its percentage of the total were low in Chinese grasslands, especially in Inner Mongolia. The low biomass of legumes in grassland might be attributable to the low growing-season temperature on the Tibetan Plateau, while in Inner Mongolia, low precipitation combined with high temperatures during the growing season may be the main reason. Although legumes in Chinese grasslands have substantial potential for nitrogen fixation and contain a variety of forage species, their ecological and economic value has been limited by their low biomass. Suggestions to enhance legume biomass in Chinese grasslands are provided.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

CeO₂-Supported TiO₂−Pt Nanorod Composites as Efficient Catalysts for CO Oxidation

Supported Pt-based catalysts have been identified as highly selective catalysts for CO oxidation, but their potential for applications has been hampered by the high cost and scarcity of Pt metals as well as aggregation problems at relatively high temperatures. In this work, nanorod structured (TiO2−Pt)/CeO2 catalysts with the addition of 0.3 at% Pt and different atomic ratios of Ti were prepared through a combined dealloying and calcination method. XRD, XPS, SEM, TEM, and STEM measurements were used to confirm the phase composition, surface morphology, and structure of synthesized samples. After calcination treatment, Pt nanoparticles were semi-inlayed on the surface of the CeO2 nanorod, and TiO2 was highly dispersed into the catalyst system, resulting in the formation of (TiO2−Pt)/CeO2 with high specific surface area and large pore volume. The unique structure can provide more reaction path and active sites for catalytic CO oxidation, thus contributing to the generation of catalysts with high catalytic activity. The outstanding catalytic performance is ascribed to the stable structure and proper TiO2 doping as well as the combined effect of Pt, TiO2, and CeO2. The research results are of importance for further development of high catalytic performance nanoporous catalytic materials

Preparation of Polyphenylene Ring Derivative Dyes with Wide Wave Absorption Properties and Their Performance Study

Some conjugated benzene ring molecules were prepared using the Sonogashira reaction, and the molecules were post-functionally modified using click chemistry. The optical and electrical band gaps were measured using UV-VIS absorption spectroscopy and the three-electrode method, and the results of both were verified against each other to prove the accuracy of the characterization. In addition, the optical performances of the material were studied by z-scan; almost all materials exhibited good nonlinear optical properties and interconversion between saturable and anti-saturable absorption due to the invocation of click reagents

Electrochemical/I− Dual-Catalyzed Access to Sulfonated Pyrazoles under External Oxidant-free Conditions

An electrochemical/I− dual-catalyzed access to sulfonated pyrazoles from pyrazolones and sodium sulfites under external oxidant-free conditions has been developed. This established electrochemical reaction works smoothly under external oxidant-free conditions, and has the advantages of good functional group tolerance, easy to gram-scale synthesis, delivering up to 95% yield for 35 examples