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To enhance the safety of direct physical interaction between humans and lower-limb exoskeletons, the actuator of the lower-limb exoskeleton should possess compliance, force controllability, and back-drivability. In this paper, a novel compact compliant force control actuator with worm gear and gear rack as transmission modes is designed to provide flexible power to the lower-limb exoskeleton. The worm gear is utilized to amplify the torque generated by the motor in the compact compliant actuator, while the gear rack is established to improve the bearing capacity. Yet, the friction is occurred between the worm gear, rack and other mechanical configurations which may lead to non-negligible force control error of the compliant actuator. A noise-tolerant zeroing neural network controller is proposed to suppress noises. Additionally, theoretical proofs are provided for the convergence performance of the noise-tolerant zeroing neural network controller, as well as the suppression of constant noise, linear disturbances, and bounded random noise. The proposed noise-tolerant zeroing neural network controller is validated on the compliant actuator through numerical simulations, experimental results, and comparison experiments, demonstrating its effectiveness in suppressing various noise and improving the convergence, stability, and robustness of the compliant actuator system. Additionally, the controller is further verified through walking experiments conducted on a knee robot. [ABSTRACT FROM AUTHOR]

To achieve sustainable desalination and water purification, solar interface evaporation technology is an effective means due to its high energy efficiency. Reasonable photothermal conversion materials and surface design are crucial for the interfacial solar evaporation process. How to design water transport routes and thermal insulating layers simultaneously is one of the major challenges to solar interface evaporation technology today. Herein, this work reports an arch-shaped wood evaporator (pine@carbon black (CB)-metal-organic framework-801 (MOF-801)-36%) for efficient, fast and continuous interfacial solar evaporation, which is composed of an arch-shaped wood substrate, MOF-801, and CB as a light absorption layer. The arch-shaped structure has a double-sided evaporation effect, which has a synergistic effect on augmenting solar evaporation efficiency. In addition, the in-situ growth of MOF-801 in pretreated wood microchannels renders the wood evaporator a significant function of reducing the equivalent enthalpy of evaporation due to the reduction of the hydrogen bonding density of water molecules as they pass through the wood channels. The best evaporation rate of the arch-shaped wood evaporator can reach 2.535 kg·m−2·h−1, and the efficiency reaches 93.7% under the irradiation of 1 sun illumination. Notably, it could be used for desalination and wastewater treatment to collect fresh water that meets drinking requirements set by the World Health Organization (WHO). This integrated evaporator provides an efficient way for commercial portable photothermal conversion and new ideas for advanced solar-driven water treatment technology. [ABSTRACT FROM AUTHOR]

Background: In view of discordance consisting in different reports, a meta-analysis was conducted to comprehensively evaluate the diagnostic efficacy of exosomal noncoding RNAs (ncRNAs) in blood and urine in the detection of bladder cancer. Methods: Eligible studies were acquired by systematic retrieval through PubMed, Cochrane Library, and Embase. The pooled diagnostic efficacy was appraised by reckoning the area under the summary receiver operating characteristic (SROC) curve. The latent sources of heterogeneity were probed by subgroup analyses and meta-regression. STATA 12.0, Meta-DiSc 1.4, and RevMan 5.3 were applied to carry out all statistical analyses and plots. Results: A total of 46 studies from 15 articles comprising 2622 controls and 3015 bladder cancer patients were included in our meta-analysis. Exosomal ncRNAs in blood and urine represented relatively satisfactory diagnostic efficacy in detecting bladder cancer, with a pooled sensitivity of 0.75, a specificity of 0.79, and an area under the SROC curve (AUC) of 0.84. Exosomal microRNAs (miRNAs) exhibited better diagnostic value with a pooled AUC of 0.91 than that of exosomal long noncoding RNAs (lncRNAs). To some extent, the heterogeneity among studies was induced by exosomal ncRNA types (miRNA or lncRNA), exosomal ncRNA profiling (single- or multiple-ncRNA), sample size, specimen types, and ethnicity. Conclusion: Exosomal ncRNAs in blood and urine may play a vital role in diagnosing bladder cancer as prospective noninvasive biomarkers; nonetheless, their clinical performance needs to be confirmed by further massive proactive researches. [ABSTRACT FROM AUTHOR]

Unripe grapes are pruned waste fruits of wine farming, while black lemons are dried products of agriculture waste lemons from lime fields. These fruit wastes are a rich source of bioactive molecules, especially polyphenols that are beneficial metabolites for human health to reduce or inhibit the oxidative stress and can be utilized in foods or pharmaceuticals. Therefore, this project aimed to study the wasted sour fruits for their polyphenols, antioxidant activities, and to support their symbiotic utilization as therapeutic and pharmaceutical products. This research was completed with solvent extraction optimization of polyphonic extracts, their in-vitro antioxidant activities using four different assays, and characterization of polyphenols by LC-ESI-QTOF-MS/MS. Efficient extraction for phenolic compounds was obtained using 80% acidified methanol with 0.1% formic acid. Results found that black lemons had a higher total phenolic content (TPC 10.11 ± 0.47 mg GAE/g), assimilated to unripe grapes (8.75 ± 0.33 mg GAE/g). Moreover, black lemons were also found with higher antioxidant potential than unripe grapes, possibly due to the presence of higher flavonoids, especially anthocyanins. 124 phenolic metabolites, including 21 phenolic acids, 45 flavonoids, 8 isoflavonoids, 2 chalcones, 7 stilbenes, 15 lignans and 25 other compounds were identified using mass spectrometry. In conclusion, these results supported the utilization of these products in combination as therapeutical ingredients in the food, biomedicine, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Main conclusion: OsNAC103 negatively regulates rice plant height by influencing the cell cycle and crosstalk of phytohormones. Plant height is an important characteristic of rice farming and is directly related to agricultural yield. Although there has been great progress in research on plant growth regulation, numerous genes remain to be elucidated. NAC transcription factors are widespread in plants and have a vital function in plant growth. Here, we observed that the overexpression of OsNAC103 resulted in a dwarf phenotype, whereas RNA interference (RNAi) plants and osnac103 mutants showed no significant difference. Further investigation revealed that the cell length did not change, indicating that the dwarfing of plants was caused by a decrease in cell number due to cell cycle arrest. The content of the bioactive cytokinin N6-Δ2-isopentenyladenine (iP) decreased as a result of the cytokinin synthesis gene being downregulated and the enhanced degradation of cytokinin oxidase. OsNAC103 overexpression also inhibited cell cycle progression and regulated the activity of the cell cyclin OsCYCP2;1 to arrest the cell cycle. We propose that OsNAC103 may further influence rice development and gibberellin–cytokinin crosstalk by regulating the Oryza sativa homeobox 71 (OSH71). Collectively, these results offer novel perspectives on the role of OsNAC103 in controlling plant architecture. [ABSTRACT FROM AUTHOR]

To address the issue of surface enrichment of A-site ions in perovskite and the resulting suppression of catalytic activity, the La0.8Sr0.2Mn0.8Cu0.2O3 was modified by treatment with dilute nitric acid (2 mol/L) and dilute acetic acid (2 mol/L). The results show that the effect of dilute nitric acid treatment on the morphology and catalytic activity of the catalyst is more significant. The specific surface area of the catalyst after dilute nitric acid treatment (268.78 m2/g) is seven times higher than before treatment (37.55 m2/g). The low-temperature catalytic oxidation activity of HCHO of the catalyst after dilute nitric acid treatment is significantly improved, achieving a 50% HCHO oxidation efficiency at 80 °C, while the original sample requires 127 °C to achieve a 50% HCHO conversion. The excellent catalytic activity of the catalyst after dilute nitric acid treatment is related to its large specific surface area, high surface-active site density, and abundant Mn4+ ions. Stability and water resistance experiments show that the catalyst after dilute nitric acid treatment has excellent reaction stability and good water resistance ability. The mechanism of the formaldehyde oxidation reaction is that formaldehyde is first oxidized to a dioxymethylene (DOM) intermediate and DOM dehydrogenation reaction is responsible for the formation of formate species (HCOO-). [ABSTRACT FROM AUTHOR]

This study develops a moderated mediation model that explores the relationship between principals' transformational leadership and older teachers' intention to delay retirement. We tested the model using a two-wave survey of data collected from a sample of 204 older teachers in primary and secondary schools in China. Our results indicate that principals' transformational leadership is positively related to older teachers' intention to delay retirement, where the relationship is mediated by organization-based self-esteem. We also found that life expectancy moderates the indirect relationship between transformational leadership, organization-based self-esteem, and older teachers' intention to delay retirement. Such an indirect relationship was stronger among old teachers with low life expectancy rather than high life expectancy. Findings enrich the literature on transformational leadership and retirement decision-making, and provide practical implications. [ABSTRACT FROM AUTHOR]

Chitobiose (COS2) efficiently lowers lipids in vivo and facilitates butyric acid enrichment during human fecal fermentation. However, whether COS2 can interact with butyric acid to generate a hypolipidemic effect remains unclear. This study examined the hypolipidemic mechanism of COS2 involving butyric acid, which could alleviate non-alcoholic fatty liver disease (NAFLD). The results revealed that COS2 administration modulated the β-oxidation pathway in the liver and restructured the short chain fatty acids in the fecal of ob/ob−/− mice. Moreover, the hypolipidemic effect of COS2 and its specific accumulated metabolite butyric acid was verified in sodium oleate-induced HepG2 cells. Butyric acid was more effective to reverse lipid accumulation and up-regulate β-oxidation pathway at lower concentrations. Furthermore, structural analysis suggested that butyric acid formed hydrogen bonds with key residues in hydrophilic ligand binding domains (LBDs) of PPARα and activated the transcriptional activity of the receptor. Therefore, the potential mechanism behind the lipid-lowering effect of COS2 in vivo involved restoring hepatic lipid disorders via butyric acid accumulation and liver–gut axis signaling. [ABSTRACT FROM AUTHOR]

A series of chemical recycling methods have been developed for polyamides (PAs) for green and sustainable technologies of plastic waste. However, the study of the essential mechanism of advanced thermo-chemical recycling of PAs is still lacking. To select efficient and green catalysts, a thorough understanding of the limiting factors of PAs hydrolysis reactions is necessary. Herein, to discuss the limiting factors of hydrolysis and the catalytic mechanism of common catalysts, polyamide 4 (PA4), a green and sustainable advanced polyamide, was studied. Firstly, the hydrolysis products and the degradation mechanism of PA4 were investigated. The only product is butyrolactam. Hydrolysis is characterized by both a depolymerization mechanism and a random chain scission mechanism. Secondly, the kinetic process of hydrolysis was investigated from the perspectives of molecular weight and solid product mass ( E α M v = 15.87 kJ / mol , E α (R sr , 1) = 44.87 kJ / mol , E α (R sr , 2) = 89.71 kJ / mol ). Finally, the existence of phase separation near the polymer chains was verified both experimentally and by molecular dynamics simulations. Furthermore, the extremely high correlation (r = 0.95, p < 0.05) between the molecular diffusion rate and the hydrolysis rate under certain reaction conditions explained the catalytic mechanism of common catalysts. Compared with the proton concentration in the system, the mass transfer efficiency in polymer chain cages is a more essential restricting factor. This mechanism is available to all PAs and provides a theoretical support for the selection of green catalysts for polyamide hydrolysis, which will greatly promote the application of chemical recycling technology. [ABSTRACT FROM AUTHOR]

Pr0.6(Sr1-xKx)0.4MnO3 polycrystalline ceramics (PSKMO, 0 ≤ x ≤ 0.25) were fabricated via using sol–gel method. The structure of PSKMO ceramics was identified to be the orthorhombic structure with Pnma space group. As K-concentration (x) rose, grain sizes increased significantly. The constituent elements of PSKMO ceramics were uniformly distributed on the surface. From the resistivity dependence of temperature (ρ-T) curves, it was clear that resistivity rose with the increase of K-concentration. Notably, the peak temperature coefficient of resistivity (TCR) and temperature (Tk) decreased as x rose in this study. This result was attributed to the disorder of cation size on A-site ( σ 2 ), which induced lattice strain leading to the random displacement of O2− ions. Further, it led to the distortion of MnO6 octahedron that promoted the localization of electrons, thereby reducing Tk. Moreover, the maximum value of TCR reached 7.60% K−1 at 299.31 K (for x = 0.15). This result suggested that the Pr0.6(Sr0.85K0.15)0.4MnO3 ceramic was befitting for application in advanced uncooled infrared bolometers. [ABSTRACT FROM AUTHOR]

Purpose: Pichia pastoris is well known for its ability to produce short and low-immunogenic humanized glycosyl chains onto recombinant glycoproteins, it was thus speculated to be applicable to synthesize oligosaccharides. In this study, generally recognized as safe (GRAS) microorganism Pichia pastoris GS115 was tested for its potential to be used as a new synthetic chassis to produce the most abundant human milk oligosaccharide 2′-fucosyllactose (2′-FL). Methods: To enable the de novo synthesis of 2′-FL, lactose transporter lac12, two enzymes of gmd, gmer, and fucosyltransferases futC were integrated into the genome of P. pastoris, under the control of constitutive PGAP promoter. Results: The resulting recombinant yeasts yielded up to 0.276 g/L through culture optimization in a 5 L bioreactor. Conclusion: To our knowledge, this is the first report of 2′-FL production in engineered Pichia pastoris. This work is a good starting point to produce 2′-FL using Pichia pastoris as a viable chassis. [ABSTRACT FROM AUTHOR]

In this paper, the form-finding of symmetric tensegrity structure is discussed and investigated by means of force density method and neural network algorithm. An optimization model based on the rank deficiency maximization is established to solve feasible force density, and the nodal coordinates are determined by eigenvalue decomposition of force density matrix. Then, the Lagrangian multiplier method can transform constrained optimization problem into unconstrained optimization problem. To avoid high-dimensional Hessian matrix calculation, noise-tolerant neural algorithm (NTNA) is exploited to calculate the unconstrained optimization problem. Numerical results indicate that the proposed noise-tolerant neural-based quasi-Newton Broyden–Fletcher–Goldfarb–Shanno (NTN-QNBFGS) form-finding method enhances convergence speed. Furthermore, the consistency between the form-finding results and analytical solutions infers that the developed method can be effectively applied to the form-finding of tensegrity robot. [ABSTRACT FROM AUTHOR]

Acrylamide (ACR), a soft electrophile, is a typical environmental and food contaminant that presents potential health hazards and, consequently, is attracting increasing attention in the quest for its control. ACR neurotoxicity has been widely reported in experimental animals and attributed to neuroinflammation; however, the mechanisms involved therein require clarification. In this study, we used a neuron cell model to investigate the mechanisms of ACR-induced neuroinflammation and pyroptosis. The results showed that ACR treatment induced lytic cell death morphologically under both the canonical pyroptotic pathway (NOD-like receptor protein 3 (NLRP3)-apoptosis-associated speck-like protein containing CARD (ASC)-cysteinyl aspartate specific proteinase 1 (caspase-1)-gasdermin D (GSDMD)-interleukin-1β (IL-1β)/interleukin-18 (IL-18)) and an alternative pyroptotic pathway (cysteinyl aspartate specific proteinase 3 (caspase-3)-gasdermin E (GSDME)-IL-1β/IL-18) in SH-SY5Y cells. Moreover, the lactate dehydrogenase (LDH) production, cytokines release, and lytic cell death induced by ACR were diminished by caspase-1 and -3 inhibitors. Furthermore, the knockdown of caspase-1 by small interfering RNA attenuated ACR-induced lytic cell death, suggesting that canonical pyroptosis (the NLRP3-caspase 1-GSDMD-IL-1β signaling axis) played a primary role in the ACR-induced pyroptosis. Of the two pyroptotic-related pathways, the NLRP3 inflammasome cascade was activated first within the 6-h period of ACR exposure, while the activation of the alternative pyroptotic pathway was delayed. Collectively, these results indicate that ACR mainly induces NLRP3-related neuroinflammation and pyroptosis in SH-SY5Y cells, which is, thus, suggestive of an alternative mechanism for ACR-induced neurotoxicity. [ABSTRACT FROM AUTHOR]

Highlights: Oxygen-respirable sponge was constructed by carbon dots-assisted synthesis strategy. The hydrophilicity and aerophilicity of Co@C–O–Cs active sites boost oxygen diffusion and the bifunctional oxygen reduction reaction and oxygen evolution reaction activities. Co@C–O–Cs-based Zn-air battery (ZAB) displays excellent specific capacity and stability, and the all-solid-state Co@C–O–Cs-based ZAB exhibits excellent flexibility. Efficient bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are vital for rechargeable Zn-air batteries (ZABs). Herein, an oxygen-respirable sponge-like Co@C–O–Cs catalyst with oxygen-rich active sites was designed and constructed for both ORR and OER by a facile carbon dot-assisted strategy. The aerophilic triphase interface of Co@C–O–Cs cathode efficiently boosts oxygen diffusion and transfer. The theoretical calculations and experimental studies revealed that the Co–C–COC active sites can redistribute the local charge density and lower the reaction energy barrier. The Co@C–O–Cs catalyst displays superior bifunctional catalytic activities with a half-wave potential of 0.82 V for ORR and an ultralow overpotential of 294 mV at 10 mA cm−2 for OER. Moreover, it can drive the liquid ZABs with high peak power density (106.4 mW cm−2), specific capacity (720.7 mAh g−1), outstanding long-term cycle stability (over 750 cycles at 10 mA cm−2), and exhibits excellent feasibility in flexible all-solid-state ZABs. These findings provide new insights into the rational design of efficient bifunctional oxygen catalysts in rechargeable metal-air batteries. [ABSTRACT FROM AUTHOR]

The relationship between corporate social responsibility (CSR) and leadership has received considerable research attention in recent decades. While there have been several qualitative reviews, quantitative and systematic reviews of CSR–leadership links remain absent. The current paper seeks to address this gap by using a bibliometric method to analyze and visualize the evolution and research trends within the CSR–leadership domain. Drawing from a sample of 1432 peer-reviewed articles, we map the landscape of the CSR–leadership research domain and identify key developments and patterns over the period 1994–2020. In addition to highlighting a range of publication trends including key theoretical influences, the findings also reveal an acceleration in the volume and breadth of CSR–leadership research. Seven subdomains (or clusters) are further identified (i.e., board characteristics, responsible leadership, emerging country context, team efficacy, CEO pay fairness, shareholder wealth, and cross-sector social partnership) and discussed based on the keywords using the log-likelihood ratio clustering algorithm. The analysis is further divided into three stages: namely, the initial stage (1991–2003), the rapid development stage (2004–2011), and the maturation stage (2012–present). These stages are used to present more fine-grained insights into the research patterns over time. We conclude by discussing implications of the bibliometric analysis and presenting several opportunities for future research. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA) plays a crucial role in response to abiotic stress as important small molecules in regulating metabolism. This study aimed to evaluate the ability of foliar spraying ABA to regulate growth quality at rice seedling stage under salt stress. Results demonstrated that salt stress strongly reduced all the growth parameters of two rice seedlings ('Chaoyouqianhao' and 'Huanghuazhan'), caused prominent decrease in the levels of photosynthetic pigments (mainly in Huanghuazhan), photosynthesis and fluorescence parameters. Salinity treatment increased the concentration of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in roots, whereas significant decreased H2O2 was found in leaves of Huanghuazhan. Additionally, salinity triggered high Na+ content particularly in leaves and enhanced catalase (CAT) activities, ascorbate peroxidase (APX) and peroxidase (POD) activities of the two rice seedlings. Nevertheless, salinity-induced increased root ascorbic acid (AsA) and glutathione (GSH) levels while decreased in leaves, which depended on treatment time. Conversely, ABA application partially or completely mitigated salinity toxicity on the seedlings. ABA could reverse most of the changed physiological parameters triggered by salt stress. Specially, ABA treatment improved antioxidant enzyme levels and significantly reduced the Na+ content of two varieties as well as increased the K+, Mg2+ and Ca2+ content in leaves and roots. ABA treatment increased the hormone contents of 1-aminocclopropane carboxylic acid (ACC), trans-zeatin (TZ), N6-isopentyladenosine (IPA), Indole-3-acetic acid (IAA), and ABA in leaves of two rice varieties under salt stress. It is suggested that ABA was beneficial to protect membrane lipid peroxidation, the modulation of antioxidant defense systems and endogenous hormonal balance with imposition to salt stress. [ABSTRACT FROM AUTHOR]

Copolyamide 4/6 (PA4/6) was synthesized by copolymerizing 2-pyrrolidone and ε-caprolactam; 2-pyrrolidone was obtained from biomass. The melting point of PA4/6 (140–190 °C) was found to be lower than those of both PA4 (265.1 °C) and PA6 (220.4 °C) for easier processing. For further applications, the effects of the structural sequence composition on the thermal and crystalline properties of the material were investigated. When the content of the PA4 structural sequence S44 was higher than that of the copolymerized structural sequence S46, the sequence S44 exhibits the crystalline behavior of PA4. However, when the S46 content was similar to the homopolymer sequence content, the melting point and crystallinity reached the respective minima, indicating the most imperfect crystallization. Kinetics analysis of non-isothermal crystallization demonstrated that the crystal grows into a two-dimensional sheet shape, which has the longest crystallization half-time (t1/2 = 2.64 min) and the highest activation energy (− 10.8 kJ mol−1). When the content of the PA6 structural sequence S66 increases to more than that of S46, the crystal exhibits three-dimensional spherical growth, t1/2 decreases to 1.25 min, the activation energy decreases to − 18.0 kJ mol−1, and consequently, the crystal structure becomes more perfect. This indicates that S46 destroys the regular arrangement of molecular chains, whereas the addition of S66 improves the crystalline structure. [ABSTRACT FROM AUTHOR]

Chitooligosaccharides (COS) are found naturally in the ocean and present a variety of physiological activities, of which hypoglycemic action has attracted considerable research attention. This study aimed to assess the therapeutic effect of COS on mice suffering from type 2 diabetes mellitus (T2DM). COS effectively reduced blood glucose and blood lipid levels and improved glucose tolerance. Furthermore, COS revealed strong inhibitory activity against α-glucosidase, reducing postprandial blood glucose levels. Molecular docking data showed that COS might interact with surrounding amino acids to form a complex and decrease α-glucosidase activity. Additionally, COS enhanced insulin signal transduction and glycogen synthesis while restricting gluconeogenesis in the liver and muscles, reducing insulin resistance (IR) as a result. Moreover, COS effectively protected and restored islet cell function to increase insulin secretion. These results indicated that COS exhibited a significant hypoglycemic effect with multi-target participation. Therefore, COS may serve as a new preventive or therapeutic drug for diabetes to alleviate metabolic syndrome. [ABSTRACT FROM AUTHOR]

Chitin and glucan in the cell wall of Ganoderma lucidum have various biological activities, but are usually not effectively utilized or discarded as insoluble waste. The aim of this study is to characterize the chitin-glucan complex extracted from Ganoderma lucidum residues and to access its application potential as a hemostatic material. Ganoderma lucidum chitin-glucan complex (GLCGC) was extracted from Ganoderma lucidum, and GLCGC was prepared into a novel Ganoderma lucidum chitin-glucan complex hydrogel (GLCGCH) with ionic liquid [AMIM]Cl. GLCGC and lyophilized GLCGCH was characterized by fourier transform infrared spectroscopy, scanning electron microscope, swelling capacity, rheological properties and hemostatic properties. Our results showed that the extracted GLCGC mainly consisted of glucan (76.7 ± 2.9%) and chitin (3.85 ± 0.55%). The hydrogel GLCGCH had three-dimensional porous structure with good performance in swelling behavior (with swelling ratios of 1181.0–1891.0%). With no cytotoxicity against mouse fibroblast cells, GLCGCH showed good blood compatibility (with hemolysis ratios of 0.9–1.5%) and in vitro blood coagulation property (with blood clotting indices of 35.3–41.9%), indicating GLCGCH has great hemostatic effect. This work provided new insight into the integrated utilization of Ganoderma lucidum residues. The prepared hydrogel could be used as a promising material for hemostatic application. [ABSTRACT FROM AUTHOR]

Acrylamide (ACR) is a typical environmental contaminant, presenting potential health hazards that have been attracting increasing attention. Its neurotoxicity is known to cause significant damage to health. However, the mechanisms of ACR-induced neurotoxicity require further clarification. This study uses a mouse model to explore how ACR-induced oxidative stress, neuronal lesions, neurotransmission impairment, and neuroinflammation mutually contribute to neurotoxicity. A distinct increase in the cellular reactive oxygen species (ROS) levels, malondialdehyde (MDA), and 8-hydroxy-2-deoxyguanosine (8-OHdG) content and a significant decrease in the glutathione (GSH) content after ACR exposure were indicative of oxidative stress. Moreover, ACR caused neurological defects associated with gait abnormality and neuronal loss while suppressing the acetylcholine (ACh) and dopamine (DA) levels and increasing the protein expression of α-synuclein (α-syn), further inhibiting cholinergic and dopaminergic neuronal function. Additionally, ACR treatment caused an inflammatory response via nuclear factor-kappa B (NF-κB) activation and increased the protein expression of NOD-like receptor protein-3 (NLRP3), consequently activating the NLRP3 inflammasome constituents, including cysteinyl aspartate specific proteinase 1 (Caspase-1), apoptosis-associated speck-like protein containing CARD (ASC), N domain gasdermin D (N-GSDMD), interleukin-1β (IL-1β), and IL-18. The results revealed the underlying molecular mechanism of ACR-induced neurotoxicity via oxidative stress, neurotransmission impairment, and neuroinflammation-related signal cascade. This information will further improve the development of an alternative pathway strategy for investigating the risk posed by ACR. The hypothetical mechanism of ACR-induced neurotoxicity in vivo. [ABSTRACT FROM AUTHOR]

We aim to assess the effects of different air pollutants on meibomian gland dysfunction (MGD). As a prospective multicenter study, 864 patients were recruited from four different regions (i.e., coal, oil, steel, and living). The oil region had a significantly lower temperature and higher O3 and SO2 concentrations than other regions. Notably, participants in oil region presented with more frequent and serious MGD signs and higher cytokine levels (median interleukin 6 [IL-6] in oil: 2.66, steel: 0.96, coal: 0.38, living: 0.56; IL-8 in oil: 117.52, steel: 46.94, coal: 26.89, living: 33; vascular endothelial growth factor [VEGF] in oil: 25.09, steel: 14.02, coal: 14.02, living: 28.47). The short-term fluctuations of cytokine levels were associated with the changes in gas levels (PM2.5 and IL-8: β = 0.016 [0.004–0.029]; O3 and IL-6: β = 0.576 [0.386–0.702]; O3 and IL-8: β = 0.479 [0.369–0.890]; SO2 and VEGF: β = 0.021 [0.001–0.047]). After long-term exposure, lid margin neovascularization (r = 0.402), meibomian gland (MG) expression (r = 0.377), MG secretion (r = 0.303), MG loss (r = 0.404), and tear meniscus height (r = − 0.345) were moderately correlated with air quality index (AQI). Individuals in oil region had more serious MGD signs and higher cytokine levels. MGD is susceptible to long-term exposure to high AQI. [ABSTRACT FROM AUTHOR]

A high-efficiency form-finding algorithm is crucially important for finding a stabilized tensegrity structure. In this paper, a modified Broyden-Fletcher-Goldfarb-Shanno noise-tolerant zeroing neural network (MBFGS-NTZNN) form-finding approach is developed and investigated for the form-finding problems of tensegrity systems. A modified BFGS algorithm (MBFGS) is employed to solve the irreversibility of the Hessian matrix, which could avoid the non-positive definite circumstance of the stiffness matrix. Additionally, the approach could be utilized to make a reduction in algorithm calculation complexity. Moreover, to find a group of suitable nodal coordinates, a zeroing neural network (ZNN) based NTZNN is considered to suppress the noise, which may include rounding errors and external disturbance during the form-finding process. Besides, the 0-stable and global convergence under the pollution of noise are verified. Eventually, numerical simulations and an application example are conducted to ascertain the superiority and availability of the MBFGS-NTZNN algorithm in the fields of form-finding. [ABSTRACT FROM AUTHOR]

Chitooligosaccharides (COSs) have various physiological activities and broad application prospects; however, their pharmacokinetics and tissue distribution remain unclear. In this study, a sensitive and selective ultra-performance liquid chromatography–mass spectrometry (UPLC–MS) method for determining chitobiose (COS 2) and chitotriose (COS 3) in rat serum and tissues was developed. This method was successfully validated based on FDA guidelines in terms of selectivity, calibration curves (lower limit of quantification was 0.002 µg/mL for COS 2 and 0.02 µg/mL for COS 3), precision (intra-day relative standard deviation of 0.04%–3.55% and inter-day relative standard deviation of 1.94%–11.63%), accuracy (intra-day relative error of − 1.81%–11.06% and inter-day relative error of − 9.41%–8.63%), matrix effects, recovery (97.10%–101.29%), stability, dilution integrity, and carry-over effects. Then, the method was successfully applied to the pharmacokinetics and tissue distribution study of COS 2 and COS 3 after intragastric and intravenous administration. After intragastric administration, COS 2 and COS 3 were rapidly absorbed, reached peak concentrations in the serum after approximately 0.45 h, and showed rapid elimination with clearances greater than 18.82 L/h/kg and half-lives lower than 6 h. The absolute oral bioavailability of COS 2 and COS 3 was 0.32%–0.52%. COS 2 and COS 3 were widely distributed in Wistar rat tissues and could penetrated the blood–brain barrier without tissue accumulation. Highlights: Report of tissue distribution of chitobiose and chitotriose after intragastric administration in rats. A trace detection method for the determination of chitobiose and chitotriose in rat serum and organs using UPLC–MS was developed and validated. Our results reveal that chitobiose and chitotriose could be quickly absorbed into the blood, with an oral bioavailability of 0.32%–0.52% in rats. [ABSTRACT FROM AUTHOR]

This paper studies robust gait features against pedestrian carrying and clothing condition changes. Inspired by the fact that humans pay more attention to pose details based on part movements when completing a gait recognition task, we introduce pose information into the convolutional network without complex computation of human modeling. We construct a multimodal set-based deep convolutional network (mmGaitSet). The mmGaitSet consists of two independent feature extractors which extract the body features from silhouettes and the part features from pose heatmaps, respectively. Joint training of two feature extractors make them complement each other. We combine intra-modal fusion and inter-modal fusion into the network. The intra-modal fusion integrates the low-level structural features and high-level semantic features, to improve the discrimination of single modality features. The inter-modal fusion fully aggregates the complementary information between different modalities to enhance the pedestrian gait presentation. The state-of-the-art results are achieved on the challenging CASIA-B dataset outperforming recent competing methods, with up to 92.5% and 80.3% average rank-1 accuracies under bag-carrying and coat-wearing walking conditions, respectively. [ABSTRACT FROM AUTHOR]

Purpose: Triglyceride–glucose (TyG) index is an emerging surrogate predictor of incident type 2 diabetes mellitus (T2DM). The study aimed to examine the association between TyG index and incident T2DM in a prospective Chinese cohort. Methods: The data were collected in 1992 and recollected in 2007 from the same group of 687 participants. The association between TyG index and T2DM was analysed. Results: During follow-up, 74 participants developed T2DM and the risk of T2DM increased with TyG index. The adjusted hazard ratio (HR) was 3.36 (95% CI: 1.52–7.39, P < 0.001) comparing the top TyG quartile to the bottom quartile. Smooth curve fitting revealed a nonlinear association and threshold effect between TyG index and incident T2DM with a nadir of risk when TyG index was around 8.51. For TyG ≤ 8.51, the risk of incident T2DM tended to decrease with per SD increase in TyG but no statistical significance was achieved (adjusted HR: 0.69, 95% CI: 0.43–1.12, P = 0.133). For TyG > 8.51, the risk of incident T2DM significantly increased by 38% with per SD increase in TyG (adjusted HR: 1.38, 95% CI: 1.14–1.67, P = 0.001). Time-dependent receiver operating curve suggested helpful discriminative power of TyG index for T2DM. It also significantly promoted the reclassification ability beyond the baseline risk model with net reclassification index of 0.159 (P = 0.020). Sensitivity analysis excluding participants with prediabetes demonstrated similar results. Conclusions: The TyG index was a significant and independent predictor for future T2DM development. The shape of relationship will require further studies. [ABSTRACT FROM AUTHOR]

Objective: Previous studies suggest a relationship between sleep disordered breathing (SDB) and lower extremity artery disease (LEAD) though disagreements remain. This study was performed to assess the association between SDB and LEAD in a metaanalysis. Methods: PubMed and Embase databases were searched for observational studies. A random-effects model incorporating between-study heterogeneity was used to pool the data. Results: The search revealed 7 studies including 152,885 participants. Patients with SDB had higher odds of LEAD (risk ratio [RR] = 1.32, 95% confidence interval [CI] = 1.07 to 1.63, p = 0.01, I 2 = 66%) compared to non-SDB participants. In subgroup analyses, SDB was related to higher odds of LEAD in patients with stroke or diabetes (RR = 3.28, p < 0.001) than in a community-derived population (RR = 1.17, p = 0.08; p for subgroup difference < 0.001). Furthermore, the odds of LEAD was increased in patients with moderate (RR = 1.34, 95% CI = 1.04 to 1.73, p = 0.02) or severe SDB (RR = 1.81, 95% CI = 1.08 to 3.03, p = 0.02), but not in those with mild SDB (RR = 0.94, 95% CI = 0.69 to 1.29, p = 0.71). Differences in study design or methods for LEAD diagnosis did not appear to affect the association between SDB and LEAD. Conclusions: Patients with SDB have higher odds of LEAD compared to non-SDB participants. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most prevalent and deadliest cancers. In this study, the anti-tumor effect of singular degree of polymerization (DP) chitooligosaccharides (COS) (DP 2–5) and the underlay molecular mechanisms were investigated on HCC cell line HepG2. MTT assay showed that (GlcN)5 have the best anti-proliferation effect among the different DP of COS (DP2-5). Furthermore, the administration of (GlcN)5 could decrease mitochondrial membrane potential, release cytochrome c into cytoplasm, activate the cleavage of Caspases9/3, thus inducing mitochondrial-mediated apoptosis in HepG2 cells (accounting for 24.57 ± 2.25%). In addition, (GlcN)5 treatment could increase the accumulation of autophagosomes. Further investigation showed that (GlcN)5 suppressed protective autophagy at the fusion of autophagosomes and lysosomes. Moreover, the inhibition of protective autophagy flux by (GlcN)5 could further decrease cell viability and increase the apoptosis rate. Our findings suggested that (GlcN)5 suppressed HepG2 proliferation through inducing apoptosis via the intrinsic pathway and impairing cell-protective autophagy. COS might have the potential to be an agent for lowering the risk of HCC. [ABSTRACT FROM AUTHOR]

To solve the problem that the overlapping parts of a retractable pier column are prone to damage, this paper proposed the reinforcing measure of setting a stiffener ring at the bottom of the steel pipe. To study how the stiffener-ring parameters influence the mechanical properties of the pier column, 12 scale model specimens (including nine specimens with stiffener-ring widths of 40, 50, and 60 mm and three unstiffened comparison specimens) were tested under axial compression. Based on the test results, the specimen load–displacement, load–deflection, and load–strain curves were analyzed, and a finite-element model of a pier column under axial compression was established to determine the optimal stiffener size. The results show that setting a stiffener ring enhances the cooperative working ability between the steel pipe and the internal filling material and restrains the lateral deformation of the pier column, thereby improving the ultimate bearing capacity and overall stability of the pier column. The ultimate bearing capacity of the pier column is related to the width and thickness of the stiffener ring. The optimal size of the stiffener ring of the model pier column is 70 mm in width and 4 mm in thickness. The present research results provide a reference for designing compressible pier columns and column stiffening in mines and have important practical significance. [ABSTRACT FROM AUTHOR]

Because of its poor engineering properties, silt often needs to be treated to meet the design requirements. Solidification using binder is one of the most common methods to improve the engineering properties of silt. Lime or/and cement are often used to treat silt. However, the mechanical properties of soil are closely related to its microstructure. Although much research has been done on the mechanical properties and stabilization mechanism of lime or/and cement solidified silt, the multi-scale research between the microstructure and macroscopic mechanics properties of solidified silt has received no attention. Therefore, in this paper, unconfined compression, mercury intrusion, and scanning electron microscope (SEM) tests were conducted on lime, cement, and lime and cement mixtures (LC) solidified silt. The microstructure parameters of particle, pore, and contact zone were extracted from SEM images. Meanwhile, the effect of curing time and binder dosage on the microstructure parameters was analyzed. In addition, the relationship between micro-parameters and macro-mechanical strength was established. The results showed that the particle diameter, particle area, contact zone diameter, and contact zone area increased with increasing curing time and binder dosage, while the pore ratio, fractal dimension of particle size distribution (PSD), and fractal dimension of contact zone size distribution (CZSD) decreased with increasing binder dosage. The unconfined compressive strength (UCS) decreased with the increase of particle roundness, pore area, pore diameter, pore ratio, and fractal dimension of PSD, and increased with increasing fractal dimension of pore size distribution (PPSD). In addition, there were no obvious relationships between UCS and pore roundness, contact zone area, and fractal dimension of CZSD. [ABSTRACT FROM AUTHOR]

Electrospinning is a highly efficient mild method to obtain stereocomplex poly(lactic acid) fibers from blends of high molecular weight (MW) poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA). However, high MW PLAs are expensive and proved difficult to avoid homocrystallites which weaken the performances. Here, di-stereoblock poly(lactic acid)s (di-sb-PLAs) with low MW of 104 g mol−1 were synthesized and electrospun into membranes. The stereocomplex (sc) crystallites were induced by sintering the amorphous as-spun membranes at 200 °C, and further improved by applying 1 MPa pressure which promoted the segment migration across fiber intersections and welded the fibers by forming new sc crystallites. Due to more readily crystallize at molecular level than the blend of PLLA and PDLA, the sintered di-sb-PLA membranes exhibited higher thermal stability, better tensile strength, and were more stable during multiple cycles of selective separating solvent and water mixtures. Increasing MW of di-sb-PLA positively affected the membrane properties and inhibited dramatical embrittlement that occurred in sintered membrane of PLLA and PDLA blend. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the relationship between cataract types and subjective visual function among patients with age-related cataract. Methods: This was a prospective, multicenter, 831 Chinese patient-based, cross-sectional study. Patients were administered the Visual Function Index-14 (VF-14) and the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) to evaluate their subjective visual function. Lens Opacities Classification System III (LOCS III) was used to evaluate the type of cataract. Relationships among these parameters were analyzed. Results: LOCS III cortical (C) and posterior subcapsular scores are negatively associated with VF-14 (r = − 0.188, P < 0.01; r = − 0.146, P < 0.01) and total score of NEI-VFQ-25 (r = − 0.223, P < 0.01; r = − 0.160, P < 0.01), respectively; LOCS III nuclear opalescence (NO) score is positively associated with VF-14 (r = 0.087, P < 0.05) and total score of NEI-VFQ-25 (r = 0.097, P < 0.05). In multiple linear regression, a decrease in the LOCS III C score is a significant predictor for improvement of the total score of NEI-VFQ-25 (β = − 1.286, P < 0.05). In contrast, an increase in LOCS III NO score is a significant predictor for improvement of VF-14 (β = 3.826, P < 0.01) and total score of NEI-VFQ-25 (β = 4.618, P < 0.01). Patients with LOCS III C score ≤ 2 have higher VF-14 (49.38 versus 43.74, P < 0.01), total (80.73 versus 71.58, P < 0.01) and subscale scores of NEI-VFQ-25 than patients with LOCS III C score > 2. Conclusion: Cortical cataract has adverse effects on subjective visual function, while mild-to-moderate nuclear cataract has positive effects. Furthermore, "LOCS III C score > 2" can be a potential cutoff as a reference for cataract surgery without self-assessing questionnaires. [ABSTRACT FROM AUTHOR]

Presently, there is growing concern worldwide regarding the adulteration of meat products. However, no reports on determining meat authenticity have been reported in China. To verify labelling compliance and evaluate the existence of fraudulent practices, 250 sausage samples were purchased from local markets in Sichuan Province and analysed for the presence of chicken, pork, beef, duck and genetically modified soybean DNA using real-time and end-point PCR methods, providing a Chinese case study on the problem of world food safety. In total, 74.4% (186) of the samples were properly labelled, while the other 25.6% (64) were potentially adulterated samples, which involved three illicit practices: product removal, addition and substitution. The most common mislabelling was the illegal addition of, or contamination with, duck. Therefore, meat authenticity monitoring should be routinely conducted. Additionally, the strict implementation of the nation's food safety laws, along with regular surveillance, should be compulsory to alleviate and deter meat adulteration. [ABSTRACT FROM AUTHOR]

Poly-γ-glutamic acid (γ-PGA) is a novel biodegradable polyamide material. Microbial fermentation is the only way to produce γ-PGA, but the molecular weight of γ-PGA varied depending on different strains and culture conditions used. The molecular weight of γ-PGA is a main factor affecting the utilization of γ-PGA. It is urgent to find an efficient way to prepare γ-PGA with specific molecular weight, especially low molecular weight. Bacillus subtilis ECUST is a glutamate-dependent strain that produces γ-PGA. In this study, a recombinant B. subtilis harboring the γ-PGA synthase gene cluster pgsBCAE of our preciously identified γ-PGA–producing B. subtilis ECUST was constructed. Assay of γ-PGA contents and properties showed that recombinant B. subtilis 1A751-pBNS2-pgsBCAE obtained the ability to synthesize γ-PGA with low molecular weight (about 10 kDa). The excessive addition of glutamate inhibited the γ-PGA synthesis, while the addition of Zn2+ could promote the synthesis of γ-PGA by increasing the transcription of pgsB but had no effect on the molecular weight of synthesized γ-PGA. Under optimized conditions, γ-PGA produced by recombinant B. subtilis 1A751-pBNS2-pgsBCAE increased from initial 0.54 g/L to 3.9 g/L, and the glutamate conversion rate reached 78%. Recombinant B. subtilis 1A751-pBNS2-pgsBCAE has the potential for efficient preparation of low molecular weight γ-PGA. [ABSTRACT FROM AUTHOR]

Hydrogen polysulfides (H2Sn, n > 1), as the oxidized forms of H2S, have attracted increasing attention these years due to their involvement in signaling transduction and cytoprotective processes. It is necessary to detect H2Sn in living systems for the study of their functions. In this work, we report a BODIPY-based near-infrared emitting fluorescence probe NIR-PHS1, with "turn-on" response, rapid response rate (within 10 min), outstanding selectivity and excellent sensitivity (detection limit = 12 nM) response towards H2Sn. The probe was successfully applied to the visualizing of endogenous H2Sn in living cells. Moreover, it can be used for near-infrared in vivo imaging of H2Sn in living mice. Therefore, NIR-PHS1 could be a potential imaging tool to study the biological roles of H2Sn in living systems. [ABSTRACT FROM AUTHOR]

Background: Intermittent hypoxia (IH) can damage endothelial cells and lead to apoptosis in obstructive sleep apnea-hypopnea syndrome (OSAHS). Hypoxia induces apoptosis in endothelial cells via upregulation of endothelin-1 (ET-1) and hypoxia inducible factor-1 alpha (HIF-1α) plays a key role in the hypoxic stress response. Purpose: We investigated an approach to diminish the negative effect of HIF-1α while maintaining its protective effect. Methods: Human umbilical vein endothelial cells (HUVECs) were subjected to sustained hypoxia (SH) or IH for 24 h, and the responses of HIF-1α, CCAAT/enhancer binding protein beta (C/EBP β), and endothelin-1 (ET-1) were assessed by western blotting. A luciferase reporter system was employed to verify the potential binding site (transcription factor binding site, TFBS) for C/EBP β in the ET-1 promoter. The specificity of regulation of ET-1 by HIF-1α via C/EBP β was evaluated by a lentiviral system. The effects of silencing of C/EBP β on IH-induced apoptosis, vascular endothelial growth factor (VEGF) protein levels, proliferation, and in vitro tube formation were studied. Results: We found that IH significantly increased HIF-1α, C/EBP β, and ET-1 in HUVECs. Knockdown of HIF-1α or C/EBP β inhibited the upregulation of ET-1 induced by IH. Blocking C/EBP β impaired IH-induced apoptosis but did not affect VEGF expression, proliferation, or in vitro tube formation. C/EBP β was shown to mediate increased ET-1 transcription by HIF-1α through the TFBS, 5′-GTTGCCTGTTG-3′, in ET-1 promoter. Conclusion: Silencing of C/EBP β can suppress apoptosis but does not affect the protective role of HIF-1α in the hypoxic stress response. [ABSTRACT FROM AUTHOR]

To explore the innovation and entrepreneurship guidance system, first of all, hierarchical analysis algorithm in clustering analysis was analysed and applied in the construction of professional innovation and entrepreneurship classification model. However, the mining results obtained with limitation of the algorithm had great optimization space. Then, new fusion algorithm was proposed by combining the algorithm with the hierarchical analysis algorithm for making up for each other. After analysis and research, the fusion algorithm was applied to the construction of professional innovation and entrepreneurship classification model, and a better clustering result was obtained, which met the requirements of building the model. Finally, the knowledge analysis was carried out on the clustering results extracted by the fusion algorithm. The results showed that the knowledge expression which was easy to accept and understand was obtained. To sum up, it briefly describes the new ideas of innovation and entrepreneurship to promote innovation and entrepreneurship, which provides a new method for data mining technology and its important branch of cluster analysis. [ABSTRACT FROM AUTHOR]

An optical fiber microdisplacement sensor based on symmetric Mach-Zehnder interferometer (MZI) with a seven-core fiber and two single-mode fiber balls is proposed. The rationality and manufacturing process of the MZI sensing structure are analyzed. The fabrication mechanism of the Mach-Zehnder sensor by CO2 laser is described in detail. Experimental results show that temperature sensitivities of the two dips are 98.65 pm/°C and 89.72 pm/°C, respectively. The microdisplacement sensitivities are 2017.71 pm/mm and 2457.92 pm/mm, respectively. The simultaneous measurement of temperature and microdisplacement is demonstrated based on the sensitive matrix. The proposed Mach-Zehnder interference sensor exhibits the advantages of compact structure, simple manufacturing process, and high reliability. [ABSTRACT FROM AUTHOR]

Cooperative knowledge creation among enterprises is becoming increasingly common in uncertain environments with rapidly changing technology and increasingly complex network relationships. The objective of this paper is to better understand why and how an uncertain network environment affects an enterprise's knowledge creation performance and knowledge creation decision-making based on a dynamic knowledge supernetwork. Regarding the methodology, we proposed a dynamic knowledge supernetwork model that contains an enterprise subnetwork and a knowledge subnetwork, constructed the knowledge creation and knowledge diffusion mechanisms, and simulated the process of knowledge creation and diffusion through a multi-agent simulation. Moreover, we utilized the empirical patent data of power technology to prove the rationality and effectiveness of our model and simulation results. The results involve three main aspects. First, knowledge performance shows an exponential growth pattern. Second, in the dynamic network, we obtain a U-shaped relationship only when the effort needed to establish new cooperation is relatively small, and the inverted U-shaped relationship disappears when the above parameter exceeds a certain threshold. Third, the knowledge-based cooperation strategy is superior to the network-based cooperation strategy, and knowledge performance increases linearly and decreases exponentially with increasing network dynamics when the effort needed to establish new cooperation does not exceed and exceeds the threshold, respectively. [ABSTRACT FROM AUTHOR]

Fermented vegetable-fruit beverages are a popular fermented food, with many potential health benefits. In this study, two commercial Lactobacillus plantarum strains were selected to ferment a beverage containing apples, pears, and carrots. The metabolites and antioxidant activities were examined during the fermentation process. Results showed that lactic acid and acetic acid accumulated gradually, whereas malic acid decreased. Glucose and fructose increased from 0.48 and 14.8 g/L to 7.7 and 20.8 g/L, respectively, while sucrose decreased slightly. Ascorbic acid also increased continuously during the fermentation to 90.74 mg/100 mL. DPPH and ABTS radical scavenging activity and FRAP reached their maximum value after 4-8 days. The accumulation of TPC, TFC, and SOD reached their maximum value on the 8th day of fermentation. Our study revealed that the L. plantarum-fermented vegetable-fruit beverage showed significant antioxidant activity, which is helpful in evaluating the fermentation end-point and developing a high-quality fermented beverage. [ABSTRACT FROM AUTHOR]

Although zircon U-Pb geochronometer has been widely used for dating metamorphism in moderate- to high-grade metamorphic rocks, it is still difficult to link the zircon U-Pb age to pressure and temperature (P-T) conditions. In this study, zircon trace elements and Hf isotopes and REE partitioning between zircon and garnet are adopted to track the formation condition of zircon in the granulites from North Tongbai Orogen, Central China. Combined with previous metamorphic P-T path results, a quantitative integrated anticlockwise P-T-t path was established for Tongbai granulites. These granulites recorded an early low-P heating followed by a dramatic pressure increase. Evidence for the prograde history (M1) is provided by cordierite, orthopyroxene and biotite inclusions in garnet. The prograde metamorphism occurred at around 443±3 Ma, with P-T conditions of ca. 730-820 °C and <6 kbar. The peak metamorphic (M2) condition is >920 °C and 8.5-10 kbar and the peak metamorphism age is ca. 432±4 Ma. At around 419 Ma, the granulites suffered an amphibolite-facies retrograde metamorphism (M3), represented by the replacement of garnet by biotite and plagioclase, and clinopyroxene by amphibole, with metamorphic condition of ca. 700 °C and ca. 7 kbar. The last retrograde metamorphism (M4) is a greenschist-facies overprint with an age of ca. 404 Ma. It is concluded that the metamorphism of Tongbai granulite lasted for more than 40 Ma, including a stage of more than 20 Ma granulite-facies metamorphism. The prolonged granulite-facies metamorphism resulted from the continuous northward subduction of the Shangdan oceanic crust beneath the North Qinling terrane. [ABSTRACT FROM AUTHOR]