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Introduction: Oxidative stress and inflammatory responses are often the predominant detrimental factors associated with spinal cord injury (SCI). This study investigates the potential therapeutic effects of albiflorin (AF) on alleviating inflammation and oxidative stress in the rat model with SCI. Methods: Initially, the behavior of SCI‐induced rats is examined by Basso−Beattie−Bresnahan score and the inclined plane examination. Then, the immunohistochemical staining of inflammasome‐related protein (for instance, NACHT, LRR, and PYD domains‐containing protein 3, NLRP3) is performed in combination with enzyme‐linked immunosorbent assay (ELISA) of corresponding proinflammatory factors to assess the immunomodulatory effects of AF. Further, the markers involved in oxidative stress are examined by ELISA and western blot analysis analyses. Results: These findings indicated that AF could alleviate motor dysfunction and the loss of neuron cells in SCI‐induced rats. Mechanistically, AF could attenuate the inflammatory responses by reducing oxidative stress and activating nuclear erythroid‐related factor 2 (Nrf2)/heme oxygenase‐1 (HO‐1) pathway in SCI rats. Depleting the antioxidant capacity by inhibiting glutathione biosynthesis could counteract the anti‐inflammatory activity of AF in SCI rats. Conclusions: Together, our data suggested that AF could serve as a potential therapeutic agent against the aggravation of SCI in rats. [ABSTRACT FROM AUTHOR]

The current COVID‐19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), is an enormous threat to public health. The SARS‐CoV‐2 3C‐like protease (3CLpro), which is critical for viral replication and transcription, has been recognized as an ideal drug target. Herein, it is identified that three herbal compounds, Salvianolic acid A (SAA), (–)‐Epigallocatechin gallate (EGCG), and Oridonin, directly inhibit the activity of SARS‐CoV‐2 3CLpro. Further, blocking SARS‐CoV‐2 infectivity by Oridonin is confirmed in cell‐based experiments. By solving the crystal structure of 3CLpro in complex with Oridonin and comparing it to that of other ligands with 3CLpro, it is identified that Oridonin binds at the 3CLpro catalytic site by forming a CS covalent bond, which is confirmed by mass spectrometry and kinetic study, blocking substrate binding through a nonpeptidomimetic covalent binding mode. Thus, Oridonin is a novel candidate to develop a new antiviral treatment for COVID‐19. [ABSTRACT FROM AUTHOR]

ABSTRACT: Supertough polylactide (PLA)/polyurethane (PU) blends were prepared by reactive blending of PLA with polyester polyol and toluene‐2,4‐diisocyanate. The free volume and interfacial compatibility between the two polymers were investigated by positron annihilation lifetime spectroscopy. The PU particles dispersed homogeneously in the PLA matrix and self‐assembled into a subinclusion microstructure, resulting in fibrils and significant plastic deformation occurs during impact process. More phase interface and free volume cavities formed between PLA and PU boundary because of a good interfacial compatibility between the two polymers, leading to smaller sizes of free volume cavities, and the increasing of the number of these cavities. Therefore, the toughness of PLA was greatly improved by blending PU. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46596. [ABSTRACT FROM AUTHOR]

In this paper, the variations in surface structure of polydimethylsiloxane elastomers before and after argon plasma treatments have been investigated by X‐ray photoelectron spectroscopy, slow positron beam, and scanning electron microscope. An inorganic silica‐like layer was probed by X‐ray photoelectron spectroscopy after 3 minutes or longer time of treatments, and the sample surface turned into totally hydrophilic. Short time (1 and 2 min) plasma exposure mainly removed preexisting low molecular weighted (LMW) siloxanes on sample surface. By using slow positron beam, the thicknesses of silica‐like layer for 3‐, 5‐, and 10‐minute–treated samples were estimated to be around 30, 66, and 91 nm, respectively. Beneath the silica‐like layer, a loose polymeric structure was also detected, which was ascribed to the accumulation of LMW siloxanes. Scanning electron microscope images showed that the silica‐like layer cracked after 10 minutes of plasma treatment, which provided direct diffusion pathways for LMW siloxanes. Hence, 10‐minute–treated sample showed rather low organic composition near surface. Slow positron beam provides valuable depth profile information for evaluating the surface aging condition of polydimethylsiloxane composite. [ABSTRACT FROM AUTHOR]

ABSTRACT Polylactide (PLA)/polyurethane (PU) composites were prepared by reactive blending method with in situ formation of PU particles via the reaction between polyester polyol (PPG) and toluene-2,4-diisocyanate (TDI). The interfacial compatibility and adhesion between the PLA and PU phases were greatly improved by the reaction of the terminal hydroxyl groups of PLA and NCO groups of TDI forming graft copolymer, as confirmed by FTIR spectroscopy. The elongation at break and notch impact strength of PLA/PU composites increased considerably with increasing PU content, and the tensile strength of PLA/PU composites decreased slightly compared with that of pure PLA. Upon addition of 12 wt % PU, the elongation at break and notch impact strength increased to 175.17% and 10.96 kJ/m2, respectively, about 27 times and 5.4 times greater than the corresponding values for the pure PLA. The tensile strength decreased only slightly to 48.65 MPa. The excellent interfacial adhesion, the dispersed PU elastomeric particles acting as stress concentration areas, and the triggering of large matrix shear yield as well as many fibrils by internal cavitation were the main mechanical toughening mechanisms. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44383. [ABSTRACT FROM AUTHOR]

ABSTRACT The canonical Wnt/β-catenin signaling pathway plays a pivotal role and is essentially required for the osteoblast differentiation and bone formation. In this study, we found ubiquitin-specific peptidase 4 (USP4) to strongly inhibit the Wnt/β-catenin signaling by removing Lysine-63 linked poly-ubiquitin chain from Dishevelled (Dvl). Ectopic expression of USP4 promoted β-catenin poly-ubiquitination and thus inhibited Wnt-induced accumulation of cytosolic β-catenin and counteracted Wnt-induced transcriptional activity. Moreover, USP4 knockdown or USP4 knockout led to an increase in the active β-catenin levels and in activation of Wnt/β-catenin-induced transcription. Functional studies in C2C12 myoblasts and KS483 osteoprogenitor cells showed that ectopic expression of USP4 resulted in impaired activation of endogenous Wnt3a-induced genes and decreased osteoblast differentiation and mineralization, whereas USP4 depletion showed the opposite effect. These results identify USP4 as a novel regulator of Dvl in Wnt/β-catenin signal and show its involvement in Wnt3a-induced osteoblast differentiation. © 2016 American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

ABSTRACT Polyaniline/TiO2−SiO2 composites were prepared by an in situ chemical oxidation polymerization approach in the presence of hybrid TiO2−SiO2 fillers. The obtained polyaniline/TiO2−SiO2 composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), thermogravimetry (TG), and current−voltage (I−V) measurements. SEM picture shows a variation in morphology of polyaniline (PANI) from fiber shape to relatively regular particle shape with increasing TiO2−SiO2 contents in the composites. The floccule-like structures were observed by high resolution TEM, which may help improve the efficiency of conductive network. SEM, XRD, TG, and FTIR spectra all reveal that a relatively strong interaction exist between TiO2−SiO2 and PANI. The I−V characteristics in such composites indicate that the charge transport is mainly governed by the space charge effects, which occurs at the interface between the conducting PANI and TiO2−SiO2. Meanwhile, PANI/TiO2−SiO2 composites exhibit significant increase in conductivity than PANI/TiO2 or PANI/SiO2. The reasons about high conductivity of PANI/TiO2−SiO2 have also been discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2288-2295, 2013 [ABSTRACT FROM AUTHOR]

Layered protonated titanate nanosheets (LPTNs) loaded with silver nanoparticles are prepared by a simple one-pot hydrothermal route in silver-ammonia solution. The as-synthesized Ag-loaded LPTNs possess large specific surface area. The Ag nanoparticles are highly dispersed on the surface of the LPTNs. They have negligible effects on the crystal structure, crystallinity, and surface area of the LPTNs but result in considerable enhancement of visible-light absorption and in a red-shift of the band gap for the LPTNs. The Ag-loaded LPTNs show enhanced photocatalytic activity for both liquid- and gas-phase reactions under visible-light irradiation. Moreover, the photocatalytic activity first increases gradually with increasing Ag loading content, and then decreases after maximizing at an optimal Ag content. At the Ag loading content of 2.87 mol % and 1.57 mol %, the Ag-loaded LPTNs exhibit the highest visible-light photocatalytic activity for degradation of rhodamine B in water and mineralization of benzene in air, respectively. An alternative possible mechanism for the enhancement of the visible-light photocatalytic activity is also proposed. [ABSTRACT FROM AUTHOR]

This article discusses a study which examined the influence of acrylic acid groups on the microstructure of high-density polyethylene (HDPE)/Bentonite (BT) and high-density polyethylene. The study used positron annihilation lifetime spectroscopy (PALS) in the examination. It found a similar mean free volume size in composites and HDPE matrices. It revealed a decrease in the ortho-positronium (o-Ps) intensity for HDPE-g-AA.

The article presents a study on the impact of the graft yield of maleic anhydride (MA) on the free volumes, thermal properties, mechanical properties and rheological behaviors of MA grafted high-density polyethylene (MA-g-HDPE). The researchers purchased high-density polyethylene (HDPE) from the Daqing Petroleum Chemical Plant in China and conducted dynamic mechanical measurements. They found that the MA-g-HDPE degradation is caused by the polymer chain's thermomechanical scission.

The homologous RNases RNase E and RNase G are widely distributed in bacteria and function in many important physiological processes, including mRNA degradation, rRNA maturation and so on. In this study, the crystallization and preliminary X-ray analysis of RNase G from Escherichia coli is described. Purified recombinant E. coli RNase G, which has 497 amino acids, was crystallized in the cubic space group F432, with unit-cell parameters a = b = c = 219.84 Å. X-ray diffraction data were collected to a resolution of 3.4 Å. [ABSTRACT FROM AUTHOR]

Silicone rubber is the outer dielectric material of the composite insulator used in high‐voltage transmission lines. A study of the microstructure evolution during corona discharge could provide a new understanding of catastrophic fracture in composite insulators. In this paper, the corona degradation process of silicone rubber is divided into three stages based on the data obtained by slow positron beam and electrochemical impedance spectroscopy. In stage I, the S parameter decreases slightly in the low‐energy range, suggesting a crosslinking process in the polymeric "skin," and the silicone rubber holds its high value of resistance, Rpore. In stage II, the organic sample surface is gradually transformed into an inorganic one. Further cracking of the surface layer contributes to a dramatic increase in the sample porosity. At the beginning of water immersion, the Bode phase angle remains approximately −50∘ at low frequency, and a diffusion‐dependent Warburg impedance is observed. In stage III, a massive number of polar groups and inorganic particles are generated and the sample fails to repel water. The increase in the sample porosity is the main factor that leads to an ingress of water and failure of the material, while the generated polar groups are the secondary factor. [ABSTRACT FROM AUTHOR]

UbiG, an O-methyltransferase from the ubiquinone-biosynthesis pathway in Escherichia coli, catalyzes two O-methyl transfer steps. The primary structures of the O-methyltransferase enzyme family used in ubiquinone synthesis are conserved in both prokaryotes and eukaryotes, but their tertiary structures and catalytic mechanisms are not yet known. Here, UbiG with an N-terminal hexahistidine tag was expressed and crystallized. Crystals grown by the hanging-drop vapour-diffusion method diffracted to 2.00 Å resolution and belonged to space group C121, with unit-cell parameters a = 119.8, b = 58.6, c = 40.2 Å, β = 105.3°. Both Matthews coefficient analysis and the self-rotation function suggested the presence of one molecule per asymmetric unit in the crystal, with a solvent content of 50.52% (V(M) = 2.48 Å(3) Da(-1)).