Pyrolysis is a promising technology to reclaim glass fibers from end-of-life wind turbine blades (WTBs), while the pyrolysis atmosphere has significant effects on the depolymerization of WTBs and the ...mechanical properties of recovered fibers. In this study, the pyrolysis performance of commercial end-of-life WTBs under different atmospheres was investigated as well as their effects on the mechanical properties of recovered fibers. The results showed that the pyrolysis gas in N2 atmosphere mainly consisted of CO2, CH4, and CO, and its calorific value was 22.53 MJ/Nm3. Various phenolic compounds were also recovered in the pyrolysis oil. After the post-oxidation of pyrolysis solid products, clean glass fibers could be reclaimed successfully. H2O was an effective gasifying agent in accelerating the decomposition of epoxy resins at 500 °C, which increased the yields of pyrolysis gas and phenolic products while inhibited the formation of char. Besides, the reactivity of residual char was improved, thereby promoting their oxidization in the post-oxidization process but causing the thermal-oxidative diffusion of surface flaws, which slightly degraded the tensile strength of recovered fibers by 5.97%. CO2 suppressed the cracking of epoxy resins and contributed to the simultaneous accumulation of uncracked resins and pyrolysis char, which then aggravated the diffusion of surface flaws by thermal oxidization and uneven heating in the post-oxidation, thereby degrading the tensile strengths of recovered fibers by 16.02%.
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•End-of-life wind turbine blades were pyrolyzed under different atmospheres.•Phenolic compounds were recovered in the pyrolysis oil of wind turbine blades.•H2O promoted the cracking of epoxy resins and improved the reactivity of char.•CO2 inhibited the cracking of resins and accumulated organic residuals over fibers.•Diffusion of surface flaws degraded the tensile strength of the recovered fibers.
Major postoperative complications translate into increased health care resource utilization, prolonged hospital stays, and increased mortality. We aimed to assess the effects of perioperative ...dexmedetomidine use on postoperative mortality and the prevalence of major complications after cardiac and noncardiac surgery.
We searched the PubMed, EMBASE, and Cochrane databases to analyze all published evidence from randomized controlled trials (RCTs) and cohort studies comparing perioperative dexmedetomidine use versus no dexmedetomidine use in adult patients undergoing cardiac and noncardiac surgery. The primary outcome was postoperative mortality. Secondary outcomes were the durations of mechanical ventilation, intensive care unit (ICU) stay, and hospital stay, and the prevalence of major complications.
Twenty-three studies in cardiac surgery (n = 7635) and 8 studies in noncardiac surgery (n = 1805) were included. In cardiac surgery, dexmedetomidine use reduced postoperative 30-day mortality (risk ratio RR, 0.35 95% CI, 0.24 to 0.51); durations of mechanical ventilation (mean difference MD, −1.56 h –2.52 to −0.60), ICU stay (MD, −0.22 day –0.35 to −0.08), and hospital stay (MD, −0.65 day –1.12 to −0.18); and the prevalences of delirium (RR, 0.50 0.36 to 0.69), atrial fibrillation (RR, 0.74 0.57 to 0.97), and cardiac arrest (RR, 0.34 0.13 to 0.87). In noncardiac surgery, dexmedetomidine use was associated with decreases in the durations of mechanical ventilation and hospital stay, with a trend toward a lower prevalence of delirium (RR, 0.57 0.32 to 1.01). The prevalence of bradycardia was increased in dexmedetomidine-treated patients undergoing cardiac surgery (RR, 1.70 1.19 to 2.44) and noncardiac surgery (RR, 1.64 1.05 to 2.58).
Dexmedetomidine use may help to reduce postoperative 30-day mortality, durations of mechanical ventilation, ICU stay, and hospital stay, and the prevalences of delirium, atrial fibrillation, and cardiac arrest in patients who undergo cardiac surgery. The majority of the benefits of dexmedetomidine were not significant in patients undergoing noncardiac surgery. An increased risk for bradycardia should be taken into consideration when prescribing dexmedetomidine. International Prospective Register of Systematic Reviews identifier: CRD42017070791.
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•The chemical structures of recovered fibers were similar to those of virgin fibers.•The recovered carbon fibers had more surface oxygen-rich functional groups.•The TSR value of the ...reCFRPs was mainly affected by the oxidation temperature.•Oxidation had a greater impact on the ISSR value of the reCFRPs than pyrolysis.•Both the TSR and ISSR values of reCFRPs exceeded 90% after the optimization.
Carbon fiber-reinforced polymer composites (CFRPs) have gained widespread usage due to their promising physiochemical properties, while this causes large amounts of waste CFRPs worldwide. In this study, carbon fibers were successfully recovered from waste CFRPs through the pyrolysis-oxidation method, and the recovered fibers were reused in remanufacturing the secondary generation CFRPs. Moreover, the individual and interactive effects of pyrolysis-oxidation recovering parameters on the mechanical strength of the resulting remanufactured CFRPs (reCFRPs) were investigated. The recovered carbon fibers displayed surface chemical structures similar to virgin fibers but with high contents of oxygen-containing bonds. The tensile strength retention (TSR) of the reCFRPs was primarily influenced by oxidation temperature. Notably, a higher oxidation temperature, especially exceeding 560 °C, amplified the impact of oxidation duration on the TSR value. Similarly, concerning interlaminar shear strength retention (ISSR), the oxidation stage had a more substantial effect compared to the pyrolysis stage. As the oxidation temperature increased from 500 °C to 600 °C, the ISSR value initially increased and then decreased, irrespective of variations in pyrolysis parameters. Additionally, through integrating the response surface methodology (RSM) analysis and multi-island genetic algorithm (MIGA) global optimization, three recovery strategies, along with the corresponding processing parameters, were proposed to meet diverse requirements. The conclusions could provide valuable insights for optimizing the recovery and reuse of carbon fibers from waste CFRPs.
Tea is one of the most popular non-alcoholic beverages in the world, and free amino acids, especially theanine, make a major contribution to the umami taste of tea. However, the genetic basis of the ...variation in amino acid content in tea plants remains largely unknown. Here, we measured the free amino acid content in fresh leaves of 174 tea accessions over two years using a targeted metabolomics approach and obtained genotype data via RNA sequencing. Genome-wide association studies were conducted to investigate loci affecting the content of free amino acids. A total of 69 quantitative trait loci (–log10(P-value)>5) were identified. Functional annotation revealed that branched-chain amino acid aminotransferase, glutamine synthetase, nitrate transporter, and glutamate decarboxylase might be important for amino acid metabolism. Two significant loci, glutamine synthetase (Glu1, P=3.71×10−4; Arg1, P=4.61×10−5) and branched-chain amino acid aminotransferase (Val1, P=4.67×10−5; I_Leu1, P=3.56×10−6), were identified, respectively. Based on the genotyping result, two alleles of CsGS (CsGS-L and CsGS-H) and CsBCAT (CsBCAT-L and CsBCAT-H) were selected to perform function verification. Overexpression of CsGS-L and CsGS-H enhanced the contents of glutamate and arginine in transgenic plants, and overexpression of CsBCAT-L and CsBCAT-H promoted the accumulation of valine, isoleucine and leucine. Enzyme activity assay uncovered that SNP1054 is important for CsGS catalyzing glutamate into glutamine. Furthermore, CsGS-L and CsGS-H differentially regulated the accumulation of glutamine, and CsBCAT-L and CsBCAT-H differentially regulated the accumulation of branched-chain amino acids. In summary, the findings in our study would provide new insights into the genetic basis of amino acids contents variation in tea plants and facilitate the identification of elite genes to enhance amino acids content.
Endoplasmic reticulum stress (ERS)-mediated myocardial inflammation and apoptosis plays an important role in myocardial ischemia/reperfusion (I/R) injury. Dexmedetomidine has been used clinically ...with sedative, analgesic, and anti-inflammatory properties. This study aimed to determine the effects of dexmedetomidine pretreatment on inflammation, apoptosis, and the expression of ERS signaling during myocardial I/R injury.
Rats underwent myocardial ischemia for 30 min and reperfusion for 6 h, and H9c2 cardiomyocytes were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury (OGD for 12 h and reoxygenation for 3 h). Dexmedetomidine was administered prior to myocardial ischemia in rats or ODG in cardiomyocytes. In addition, the α2-adrenergic receptor antagonist (yohimbine) or the PERK activator (CCT020312) was given prior to dexmedetomidine treatment.
Dexmedetomidine pretreatment decreased serum levels of cardiac troponin I, reduced myocardial infarct size, alleviated histological structure damage, and improved left ventricular function following myocardial I/R injury in rats. In addition, dexmedetomidine pretreatment increased cell viability and reduced cytotoxicity following OGD/R injury in cardiomyocytes. Mechanistically, the cardioprotection offered by dexmedetomidine was mediated via the inhibition of inflammation and apoptosis through downregulating the expression of the ERS signaling pathway, including glucose-regulated protein 78 (GRP78), protein kinase R-like endoplasmic reticulum kinase (PERK), C/EBP homologous protein (CHOP), inositol-requiring protein 1 (IRE1), and activating transcription factor 6 (ATF6). Conversely, the protective effects of dexmedetomidine were diminished by blocking the α2 adrenergic receptors with yohimbine or promoting PERK phosphorylation with CCT020312.
Dexmedetomidine pretreatment protects the hearts against I/R injury via inhibiting inflammation and apoptosis through downregulation of the ERS signaling pathway. Future clinical studies are needed to confirm the cardioprotective effects of dexmedetomidine in patients at risk of myocardial I/R injury.
A novel, practical, and scalable approach for the synthesis of eldecalcitol (2), via the Horner–Wadsworth–Emmons (HWE) olefination of A-ring and C/D-ring fragments, has been described. The improved ...route was carried out to produce the key intermediate chiral epoxide 17 in good yield (13 steps, 9.0% overall yield) and high optical purity based on the utilization of d-mannose as a readily accessible, economically attractive chiral raw material. This process employed d-mannose as the chiral pool to directly assemble all the stereocenters of the A-ring fragment, thereby reducing the complexity of the chiral separation process, eliminating the need for asymmetric oxidation required for the construction of the C-3 stereocenter, and ultimately increasing the efficiency.
The recently discovered surface-group-dependent superconductivity in Nb2C-MXene fabricated by the molten salts method is attracting wide attention. However, regarding the superconductivity of ...Nb2C-MXene with functional F groups (Nb2CFx), there were some conflicting results in experimental and theoretical studies. Herein, we systematically carried out experimental and theoretical investigations on the superconductivity in Nb2C-MXene with the Cl functional group (Nb2CClx) and Nb2CFx. The experimental results of the Meissner effect and zero resistivity have proved that Nb2CClx is superconducting with the transition temperature (Tc) ∼ 5.2 K. We extract its superconducting parameters from the temperature dependence of resistivity and the field dependence of the magnetization. The Ginzburg-Landau parameter κGL is estimated to be 2.41, indicating that Nb2CClx is a typical type-Ⅱ superconductor. Conversely, both magnetic and electrical transport measurements demonstrate that Nb2CFx is not superconducting. The first-principles density functional theory (DFT) calculations show that the Tc of Nb2CClx is ∼ 5.2 K, while Nb2CFx is dynamically unstable with imaginary frequency in phonon spectrum, which is in good agreement with the experimental results. Our studies not only are useful for clarifying the present inconsistency but also offer referential significance for future investigations on the superconductivity of MXenes.
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•Hollow ZnCo2O4 porous microspheres were synthesized based on a template-free method.•This special nanostructure of ZnCo2O4 was first applied as cathode for Li-S battery.•It shows a ...reversible capacity of 642 mAh g−1 at a very high current density of 10C.•It can keep a discharge capacity at 704 mAh g−1 after 1000 cycles at 2C.
Porous hollow cobalt acid zinc (ZnCo2O4) spheres with special surface morphology were synthesized by a simple template-free method. ZnCo2O4 has both impactful adsorption and catalytic ability to lithium polysulfides (LiPSs), in addition, its porous surface greatly increases the number of active. Moreover, the hollow structure enables the ZnCo2O4 spheres to effectively alleviate the expansion of electrode volume during the charging and discharging process applied in lithium-sulfur batteries. The cell with ZnCo2O4 spheres as the host shows a large reversible capacity of 600 mAh g−1 at a high rate of 10C, more importantly, the cycle stability of the lithium-sulfur battery has been greatly improved. At a high current density of 2C, the battery can still release a discharge capacity more than 700 mAh g−1 after 1000 cycles with the capacity decay rate of only 0.015% per cycle.
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