The 26S proteasome catalyzes the degradation of most proteins in mammalian cells. To better define its composition and associated regulatory proteins, we developed affinity methods to rapidly purify ...26S proteasomes from mammalian cells. By this approach, we discovered a novel 46‐kDa (407 residues) subunit of its 19S regulatory complex (previously termed ADRM1 or GP110). As its N‐terminal half can be incorporated into the 26S proteasome and is homologous to Rpn13, a 156‐residue subunit of the 19S complex in budding yeast, we renamed it human Rpn13 (hRpn13). The C‐terminal half of hRpn13 binds directly to the proteasome‐associated deubiquitinating enzyme, UCH37, and enhances its isopeptidase activity. Knockdown of hRpn13 in 293T cells increases the cellular levels of ubiquitin conjugates and decreases the degradation of short‐lived proteins. Surprisingly, an overproduction of hRpn13 also reduced their degradation. Furthermore, transfection of the C‐terminal half of hRpn13 slows proteolysis and induces cell death, probably by acting as a dominant‐negative form. Thus in human 26S proteasomes, hRpn13 appears to be important for the binding of UCH37 to the 19S complex and for efficient proteolysis.
Pyroptosis, a type of programmed cell death, is characterized by cell swelling with bubbles, and the release of inflammatory cell cytokines. Piperlongumine (PL) is a natural bioactive product ...extracted from Piper longum L, which can effectively exert anti-tumor activities in cancer. However, the effects and the exact molecular mechanisms of PL in esophageal squamous cell carcinoma (ESCC) remain unclear. This research aimed to investigate the role and mechanism of PL on ESCC in vitro and in vivo. In vitro, the MTT results showed that the IC50 of PL in ESCC cells was 28.55 μM. Moreover, PL significantly suppressed malignant behavior by promoting pyroptosis of ESCC cells by inhibiting proliferation, migration, invasion, and colony formation of KYSE-30 cells, up-regulating expressions of ASC, Cleaved-caspase-1, NLRP3, and GSDMD, while inducing the generation of ROS. Further, NRF2 knockdown promoted TXNIP expression, while overexpression of NRF2 inhibited TXNIP expression. However, after PL treatment, this effect was reversed. In addition, PL significantly inhibited the malignant behavior of ESCC cells while the inhibitory effects were reversed by DMF (NRF2 activator) or NAC (ROS eliminator) treatment. Finally, PL markedly increased expressions of ASC, Cleaved-caspase-1, NLRP3, GSDMD, and the generation of ROS while the effects were reversed by TXNIP knockdown or RUS (TXNIP inhibitor) treatment. In vivo, the KYSE-30 xenograft model confirmed that PL inhibited the growth of ESCC transplanted tumors by promoting cell pyroptosis. In conclusion, the results suggested that PL inhibited the malignant behavior of ESCC cells in vitro and tumorigenesis of ESCC in vivo by inhibiting NRF2 and promoting ROS-TXNIP-NLRP3-mediated pyroptosis.
•PL has been shown to inhibit the malignant behavior of ESCC for the first time.•The NRF2-ROS-TXNIP-NLRP3 signaling pathway was identified as a crucial signaling pathway in PL-induced pyroptosis.•PL inhibited tumorigenesis by promoting cell pyroptosis in ESCC.•PL can be used as a potential therapeutic drug in patients with ESCC.
Fast pyrolysis, which is comparable with the enzyme or acid hydrolysis, should be considered for further development for fermentable levoglucosan (LG) production. This manuscript offers a broad ...review of the current status and future research perspectives of LG and its hydrolysates production from lignocellulosic biomass by fast pyrolysis for fermentation. The utilization, distribution and formation paths of LG from cellulose are presented. In consideration of the complexity of cellulose structure and lignocellulosic components, the influence of the major individual components (cellulose, hemicellulose, lignin and ash) and the structural properties (particle size, degree of polymerization and crystallinity) on the LG formation are reviewed. Aiming to further improve the yield of LG and the fermentability of pyrolysate, a number of pretreatment methods (e.g. hot-water pretreatment, acid pretreatment, acid impregnation) prior to fast pyrolysis, hydrolysis of LG and detoxification before fermentation, and microbial production of valuable products are also discussed in detail. At last, a brief conclusion for the challenge in this topic is provided. The low content of LG and the presentence of inhibitors to biocatalysts in the pyrolysate of lignocelluloses hamper the fermentable utilization of pyrolytic sugars, which need further investigation and improvement to make this process feasible.
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•Levoglucosan (LG) from biomass by fast pyrolysis is reviewed in details.•Biomass components and structural properties on LG formation are presented.•Pretreatment techniques for fast hydrolysis are summarized.•Detoxification and hydrolysis of LG for fermentation are introduced.•Challenges for LG production and fermentation are proposed.
Strontium titanate (SrTiO 3 ) is a promising n-type thermoelectric material at high temperature. However, to date, its reported high dimensional figure of merit ( zT ) > 0.4 has only been achieved in ...a narrow temperature range near 1000 K. In this study, zT values of >0.4 were achieved in the broad temperature range of 769–1009 K in bulk SrTiO 3 co-doped with La and Nb with in situ precipitation of second phases of NbC and TiO 2−δ . The electronic transport properties of the samples were optimized by adjusting the doping ratio, resulting in a large power factor of 1.82 mW m −1 K −2 at 622 K for 7 mol% La–7 mol% Nb-doped SrTiO 3 . Notably, the power factor (PF) decreased more gradually with increasing temperature, resulting in a high PF of 1.28 mW m −1 K −2 even at 1009 K. In addition, precipitation of the second phases occurred during sintering of the mixture of La–Nb doped SrTiO 3 nano powder and carbon powder, which provided additional phonon scattering centers except for the phonon scattering centers of La and Nb point defects. This high thermoelectric performance achieved over a broad temperature range could be beneficial for broadening the range of application temperatures for bulk polycrystalline SrTiO 3 . Furthermore, the tailoring strategy of co-doping, an in situ second phase, and oxygen vacancies applied in this study may be applicable to other oxide thermoelectric materials.
Bend-forming is an efficient and economical method to manufacture curved sandwich panels, and the major concerns for fabricating precise products are forming characteristics and springback ...prediction. In this paper, numerical simulation, analytical approach, and forming experiments were conducted to assess the multi-point cylindrical bend-forming process of bi-directional trapezoidal sandwich panel. Analysis was performed on the deformation characteristics, regularity, and forming defects of sandwich panel in the early stage. And afterwards, equivalent elastic constants of the core layer were deduced by the semi-analytic approach combined with finite element method (FEM). On this basis, a theoretical model was established to calculate bending moments and predict springback within formable range. The results indicate that the stress of face sheet in the welded area was obviously lower than that in the suspended area. The core cell was primarily deformed by changing the angle between the inclined plane and the platform, and the deformation of the cell layer mainly occurred in the transition surface area. The dimple and straight plane effect are the most common forming defects during the bending process. The main factors that affect the forming defects are face sheet thickness and bending radius. The springback amount of the sandwich panel approximates the equivalent thickness plate. Thus, it is easy to control the forming precision for small springback, and the springback ratio increases with the increase of bending curvature radius. The springback in theoretical model and experiment has an error of less than 1.0 mm, verifying the accuracy of the theoretical prediction model.
To improve the corrosion resistance of Mg alloy, Zn coating was formed by cold spraying technology followed by post shot-peening processing. The phase structure, microstructure, and corrosion ...properties of the cold-sprayed Zn coatings before and after shot peening process were all investigated. The cold-sprayed Zn coating presented a porous and roughness structure. However, the Zn coatings after shot peening illustrated densifications with flattened and elongated Zn particles on the top layer. The mass and thickness losses of Zn coatings after shot peening both increased with the impact pressure owing to the competition between the densification and the erosion of Zn coatings. The microhardness of Zn coatings after shot peening increased from 40 HV0.025 to 64 HV0.025 due to factors like densification structure, work hardening, and grain refinement. It also displayed decreasing profiles from the surface to the inner bulk. The anti-corrosion properties of Zn coatings after shot-peening were improved by about one fold when compared to the cold-sprayed Zn coating owing to the presence of compact top layers. The corrosion changes in behaviors of Zn coatings before and after shot peening were clarified by comparing the morphologies and phase structures after immersion in stimulated body fluid. In sum, the proposed simple post-processing strategy looks promising for improving the corrosion resistance of cold-sprayed Zn coatings modified Mg alloy substrates, which might be useful for future use in bone implants.
•Cold-spayed Zn coatings were improved by shot peening with different pressures.•Flattening and elongated particles were observed in dense top layers after shot peening.•Zn coatings after shot peening showed increased microhardness with decreasing profiles.•Anti-corrosion properties of Zn coatings were increased by shot-peening.•Corrosion behaviors of different Zn coatings were discussed after immersion in SBF.
Rod-shaped HSUZ-4 zeolite is discovered with distinctive activity and stability for DME carbonylation, which is dominated by the acid concentration and the number of 8-MR pore openings.
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•Both the surface architecture and acid distribution of HSUZ-4 zeolite can be precisely regulated.•The structure-performance correlations between HSUZ-4 zeolite and carbonylation performance were systematically studied.•The catalytic activity was determined by the synergistic effect of the acid concentration and the number of 8-MR pore openings.•T1-O12 site located in 8-MR channel was energetically favorable for catalyzing DME carbonylation.
Carbonylation, an important reaction to realize controllable carbon chain growth by C–C coupling, is highly attractive but challenging due to the rapid deactivation behavior. HSUZ-4 zeolite is a new candidate with a high durability for catalyzing dimethyl ether (DME) carbonylation. However, its industrial application is still impeded because of the low activity. In the present paper, the activity of DME carbonylation over rod-shaped HSUZ-4 zeolite can be significantly improved by adjusting the acid distribution. Results show that the DME carbonylation performance over rod-shaped HSUZ-4 zeolite was determined by the synergistic effect of the acid concentration and the number of 8-MR pore openings. Furthermore, we firstly revealed that the carbonylation reaction occurs preferentially at T1-O12 site located in 8-MR with a quantum-chemical method. Additionally, we discovered that the activity of HSUZ-4 zeolite can be further improved by promoting the crystal growth along the c axis because more 8-MR channels are exposed. This work will provide a detailed theoretical guidance for the rational designing and fabricating more efficient catalysts for the carbonylation reaction, which is highly attractive but remains challenge for the synthesis of C2+ oxygenate chemicals from syngas and/or CO2.
•Six N rates were applied to winter oilseed rape under RFFM and flat cultivation patterns.•RFFM and N fertilization both greatly increased LAI, ADM, seed yield and WP.•The optimal N-application ...amount under RFFM and flat cultivation patterns was 240 and 180 kg ha−1, respectively.
Poor soil conditions and drought stress are two main factors restricting the agriculture production in arid and semiarid areas of China. The ridge-furrow film mulching (RFFM) cultivation pattern has been shown to have the ability of improving yield and water productivity (WP) of maize, wheat and potato. However, its effect on winter oilseed rape is not clear. A two-year (2014–2016) field experiment was conducted to determine whether the RFFM cultivation pattern has the potential of improving winter oilseed rape productivity under dryland conditions. The optimal nitrogen (N) application rate for winter oilseed rape maximum yield under the RFFM cultivation pattern was also measured. Winter oilseed rape was planted in RFFM and flat cultivation patterns, both with six nitrogen (N) application rates (0, 60, 120, 180, 240 and 300 kg ha−1). The results showed that compared to the flat cultivation pattern, the RFFM cultivation pattern greatly increased leaf area index (LAI) by 18.7% on average, aboveground dry matter (ADM) by 25.6% at harvest, seed yield by 23.8% and WP by 32.7%, and decreased evapotranspiration (ET) by 7.2%. Application of N fertilizer remarkably increased LAI, ADM, ET, seed yield and WP of winter oilseed rape under both cultivation patterns. Under the RFFM cultivation pattern, average seed yield, WP, and economic benefit in 240 kg N ha−1 were 2904 kg ha−1, 8.8 kg ha−1 mm−1, and 1259.6 $ ha−1, respectively, and were significantly higher than the other five N rates. The optimal N-application amount for maximum winter oilseed rape productivity under the RFFM cultivation pattern was found to be 240 kg N ha−1. In conclusion, the RFFM cultivation pattern has the potential of improving the seed yield and WP of winter oilseed rape in northwest China.
Anode modification by doping silver nano-particles (Ag NPs) into poly(3,4-ethylene dioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and cathode interfacial modification by inserting ...solution-processed bathophenanthroline (sBphen) in CH 3 NH 3 PbI 3−x Cl x based planar perovskite solar cells are investigated. Prior to the optical effect such as localized surface plasmon resonance, the Ag-NPs distributed in PEDOT:PSS mainly cause an improvement in the electrical property of PEDOT:PSS–Ag NPs composite films. The sBphen interfacial layer modified the surface morphology of perovskite/phenyl-C 61 -butyric acid methyl ester (PC 61 BM) films by filling the voids on the surface of perovskite/PC 61 BM effectively, which led to an obvious improvement in the fill factor. Accordingly, an efficient device with a power conversion efficiency of 15.75% was achieved due to the simultaneous cathode and anode interfacial modification.
This meta-analysis (MA) aims at comparing the clinical outcomes of resurfacing and nonresurfacing the patella in patients undergoing total knee arthroplasty in the treatment of knee osteoarthritis.
...Randomized controlled trials were included by retrieving data from electronic English databases. Both fixed and random-effects models were employed, and standardized mean difference and 95% confidence intervals were calculated. Stata13.1 software was used for statistical analysis for all the studies included to compare the differences in improving Knee Society Clinical Score and Knee Society Function Score as well as the reduction in rates of infection, reoperation, and anterior knee pain.
A total of 394 studies were initially included in this MA. About 20 randomized controlled trials which met the inclusion criteria were finally enrolled in this MA. The results of our MA showed that the reoperation rate of the patellar resurfacing group was lower than that of the nonresurfacing group. The subgroup analysis was performed according to the follow-up time and revealed that the increase in the Knee Society Clinical Score was higher in the patellar resurfacing group than that in the nonresurfacing group in the follow-up period of 1 to 2 years. The risk of reoperation rate was lower in the patellar resurfacing group than that in the nonresurfacing group, while there were no statistical differences in the follow-up time over 2 years.
Our study suggests that during the follow-up of 1 to 2 years, patellar resurfacing can significantly increase the Knee Society Clinical Score and reduce the reoperative rates in patients with knee osteoarthritis.
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