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result(s) for
"Duan, Meng"
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Energy consumption, environmental pollution, and technological innovation efficiency: taking industrial enterprises in China as empirical analysis object
by
Meng, Xiao-na
,
Miao, Cheng-lin
,
Wu, Xin-yu
in
Aquatic Pollution
,
Atmospheric Protection/Air Quality Control/Air Pollution
,
China
2020
Facing increasingly serious environmental problems, technological innovation has become the key for industrial enterprises to coordinate energy conservation and emission reduction constraints and achieve steady growth of the industrial economy. Considering the impact of energy consumption and environmental pollution on the technological innovation efficiency of industrial enterprises, this paper incorporates industrial energy consumption, pollution control, and wastewater and exhaust emissions into the technical inefficiency equation. Based on the panel data of industrial enterprises in 30 provinces and autonomous regions in China from 2009 to 2016, the stochastic frontier analysis (SFA) model is used to study the effect of energy consumption and environmental pollution on technological innovation efficiency of industrial enterprises. The research results show that reducing energy consumption and increasing pollution treatment investment both have a significant driving effect on the improvement of industrial enterprises’ technological innovation efficiency. Industrial wastewater and exhaust emissions have the opposite effect; unreasonable input mode of pollution control and personnel allocation have hindered the improvement of industrial enterprises’ technological innovation efficiency. The average annual trend of technological innovation efficiency in industrial enterprises shows a curve of first rising, then falling, and rising again. The average values of Chongqing, Zhejiang, and Hunan rank in the top three, and the average values of Qinghai, Heilongjiang, and Inner Mongolia rank the bottom three. The average values of other provinces are higher than 0.9, and the difference is small. A suitable incentive mechanism should be established for industrial enterprises to save energy and reduce emissions and strengthen pollution control, improve the training program for environmental protection technical personnel, and provide important support for improving the green competitiveness of industrial enterprises.
Journal Article
Organocatalytic enantioselective dearomatization of thiophenes by 1,10-conjugate addition of indole imine methides
2021
Catalytic asymmetric dearomatization (CADA) is a powerful tool for the rapid construction of diverse chiral cyclic molecules from cheap and easily available arenes. This work reports an organocatalytic enantioselective dearomatization of substituted thiophenes in the context of a rare remote asymmetric 1,10-conjugate addition. By suitable stabilization of the thiophenyl carbocation with an indole motif in the form of indole imine methide, excellent remote chemo-, regio-, and stereocontrol in the nucleophilic addition can be achieved with chiral phosphoric acid catalysis under mild conditions. This protocol can be successfully extended to the asymmetric dearomatization of other heteroarenes including selenophenes and furans. Control experiments and DFT calculations demonstrate a possible pathway in which hydrogen bonding plays an important role in selectivity control.
Catalytic asymmetric dearomatization is a powerful tool for the rapid construction of diverse chiral cyclic molecules from cheap and easily available arenes. Here the authors show an organocatalytic enantioselective dearomatization of substituted thiophenes in the context of a rare remote asymmetric 1,10-conjugate addition.
Journal Article
Apelin-13-Loaded Macrophage Membrane-Encapsulated Nanoparticles for Targeted Ischemic Stroke Therapy via Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis
2024
Ischemic stroke is a refractory disease wherein the reperfusion injury caused by sudden restoration of blood supply is the main cause of increased mortality and disability. However, current therapeutic strategies for the inflammatory response induced by cerebral ischemia-reperfusion (I/R) injury are unsatisfactory. This study aimed to develop a functional nanoparticle (MM/ANPs) comprising apelin-13 (APNs) encapsulated in macrophage membranes (MM) modified with distearoyl phosphatidylethanolamine-polyethylene glycol-RVG29 (DSPE-PEG-RVG29) to achieve targeted therapy against ischemic stroke.
MM were extracted from RAW264.7. PLGA was dissolved in dichloromethane, while Apelin-13 was dissolved in water, and CY5.5 was dissolved in dichloromethane. The precipitate was washed twice with ultrapure water and then resuspended in 10 mL to obtain an aqueous solution of PLGA nanoparticles. Subsequently, the cell membrane was evenly dispersed homogeneously and mixed with PLGA-COOH at a mass ratio of 1:1 for the hybrid ultrasound. DSPE-PEG-RVG29 was added and incubated for 1 h to obtain MM/ANPs.
In this study, we developed a functional nanoparticle delivery system (MM/ANPs) that utilizes macrophage membranes coated with DSPE-PEG-RVG29 peptide to efficiently deliver Apelin-13 to inflammatory areas using ischemic stroke therapy. MM/ANPs effectively cross the blood-brain barrier and selectively accumulate in ischemic and inflamed areas. In a mouse I/R injury model, these nanoparticles significantly improved neurological scores and reduced infarct volume. Apelin-13 is gradually released from the MM/ANPs, inhibiting NLRP3 inflammasome assembly by enhancing sirtuin 3 (SIRT3) activity, which suppresses the inflammatory response and pyroptosis. The positive regulation of SIRT3 further inhibits the NLRP3-mediated inflammation, showing the clinical potential of these nanoparticles for ischemic stroke treatment. The biocompatibility and safety of MM/ANPs were confirmed through in vitro cytotoxicity tests, blood-brain barrier permeability tests, biosafety evaluations, and blood compatibility studies.
MM/ANPs offer a highly promising approach to achieve ischemic stroke-targeted therapy inhibiting NLRP3 inflammasome-mediated pyroptosis.
Journal Article
PD1Hi CD8+ T cells correlate with exhausted signature and poor clinical outcome in hepatocellular carcinoma
2019
BackgroundCD8+ T cells differentiate into exhausted status within tumors, including hepatocellular carcinoma (HCC), which constitutes a solid barrier to effective anti-tumor immunity. A detailed characterization of exhausted T cells and their prognostic value in HCC is lacking.MethodsWe collected fresh tumor tissues with adjacent non-tumor liver tissues and blood specimens of 56 HCC patients, as well as archived samples from two independent cohorts of HCC patients (n = 358 and n = 254), who underwent surgical resection. Flow cytometry and multiplex immunostaining were used to characterize CD8+ T cells. Patient prognosis was evaluated by Kaplan-Meier analysis and Cox regression analysis.ResultsCD8+ T cells were classified into three distinct subpopulations: PD1Hi, PD1Int and PD1−. PD1Hi CD8+ T cells were significantly enriched in tumor compared to adjacent non-tumor liver tissues. PD1Hi CD8+ T cells highly expressed exhaustion-related inhibitory receptors (TIM3, CTLA-4, etc.) and transcription factors (Eomes, BATF, etc.). In addition, PD1Hi CD8+ T cells expressed low levels of cytotoxic molecules and displayed a compromised capacity to produce pro-inflammatory cytokines while the expression of anti-inflammatory IL-10 was up-regulated following mitotic stimulation. Furthermore, PD1Hi CD8+ T cells shared features with tissue resident memory T cells and were also characterized in an aberrantly activated status with an apoptosis-prone potential. In two independent cohorts of HCC patients (n = 358 and n = 254), we demonstrated that PD1Hi or TIM3+PD1Hi CD8+ T cells were significantly correlated with poor prognosis, and the latter was positioned in close proximity to PD-L1+ tumor associated macrophages.ConclusionThe current study unveils the unique features of PD1Hi CD8+ exhausted T cells in HCC, and also suggests that exhausted T cells could act as a biomarker to select the most care-demanding patients for tailored therapies.
Journal Article
Extraction optimization and influences of drying methods on antioxidant activities of polysaccharide from cup plant (Silphium perfoliatum L.)
by
Zhou, Hai-Zhu
,
Wu, Hong-Xin
,
Shang, Hong-Mei
in
Agricultural production
,
Air drying
,
Animal sciences
2017
Response surface methodology (RSM) was used to investigate the extraction condition of polysaccharide from cup plant (Silphium perfoliatum L.) (named CPP). Water to raw material ratio (10-30 mL/g), extraction time (40-80 min) and extraction temperature (60-100°C) were set as the 3 independent variables, and their effects on the extraction yield of CPP were measured. In addition, the effects of drying methods including hot air drying (HD), vacuum drying (VD) and freeze drying (FD) on the antioxidant activities of CPP were evaluated. The results showed that the optimal condition to extract CPP was: water to raw material ratio (15 mL/g), extraction time (61 min), and extraction temperature (97°C), a maximum CPP yield of 6.49% was obtained under this condition. CPP drying with FD method showed stronger reducing power (0.943 at 6 mg/mL) and radical scavenging capacities against DPPH radical (75.71% at 1.2 mg/mL) and ABTS radical (98.06 at 1.6 mg/mL) than CPP drying with HD and VD methods. Therefore, freeze drying served as a good method for keeping the antioxidant activities of polysaccharide from cup plant. The polysaccharide from cup plant has potential to use as a natural antioxidant.
Journal Article
Intraplate Basalts in Eastern Continental China Record the Subduction History of the Pacific Plate
2025
To assess whether intraplate magmatism in eastern continental China records the subduction history of the Pacific plate, we plotted elemental compositions of the volcanic rocks in this region since the Early Cretaceous as a function of age. These rocks show distinct compositional transitions at ∼110 and ∼50 Ma, coinciding with the cessation of paleo‐Pacific plate subduction and initiation of present‐day western Pacific plate subduction, respectively. The dehydration of subducted oceanic slab in the mantle transition zone (MTZ) (410–660 km) governs key parameters such as overlying lithospheric thickness, melt extraction depth, partial melting extent, and asthenospheric mantle enrichment, ultimately controlling the compositions of mantle‐derived melts. Therefore, continental intraplate volcanism in regions with (present or past) subducted oceanic plates stagnant in the MTZ records the subduction history of adjacent oceanic plates.
Journal Article
Why •CF2H is nucleophilic but •CF3 is electrophilic in reactions with heterocycles
2024
Radical substitution is a useful method to functionalize heterocycles, as in the venerable Minisci reaction. Empirically observed regiochemistries indicate that the CF
2
H radical has a nucleophilic character similar to alkyl radicals, but the CF
3
radical is electrophilic. While the difference between •CH
3
and •CF
3
is well understood, the reason that one and two Fs make little difference but the third has a large effect is puzzling. DFT calculations with M06-2X both reproduce experimental selectivities and also lead to an explanation of this difference. Theoretical methods reveal how the F inductive withdrawal and conjugative donation alter radical properties, but only CF
3
becomes decidedly electrophilic toward heterocycles. Here, we show a simple model to explain the radical orbital energy trends and resulting nucleophilicity or electrophilicity of fluorinated radicals.
Empirically observed regiochemistries indicate that the CF
2
H radical has a nucleophilic character similar to alkyl radicals, but the CF
3
radical is electrophilic in reactions with heterocycles. Here, the authors report DFT calculations, reproducing experimental selectivities and leading to an explanation of this difference.
Journal Article
Boosting the Faradaic Efficiency of Br−‐Mediated Photoelectrochemical Epoxidation by Local Acidity on α‐Fe2O3
by
Duan, Meng‐Yu
,
Chen, Chun‐Cheng
,
Yang, Si‐Peng
in
alkenes epoxidation
,
Br−/HBrO‐mediated
,
Competition
2024
The redox mediated photoelectrochemical (PEC) or electrochemical (EC) alkene oxidation process is a promising method to produce high value‐added epoxides. However, due to the competitive reaction of water oxidation and overoxidation of the mediator, the utilization of the electricity is far below the ideal value, where the loss of epoxidation's faradaic efficiency (FE) is ≈50%. In this study, a Br−/HOBr‐mediated method is developed to achieve a near‐quantitative selectivity and ≈100% FE of styrene oxide on α‐Fe2O3, in which low concentration of Br− as mediator and locally generated acidic micro‐environment work together to produce the higher active HOBr species. A variety of styrene derivatives are investigated with satisfied epoxidation performance. Based on the analysis of local pH‐dependent epoxidation FE and products distribution, the study further verified that HOBr serves as the true active mediator to generate the bromohydrin intermediate. It is believed that this strategy can greatly overcome the limitation of epoxidation FE to enable future industrial applications. A method of PEC Br−/HBrO mediated alkene epoxidation with a near‐quantitative selectivity and 100% FE is achieved by modulating Br− concentration and the local acidity around the interface of α‐Fe2O3 photoanode, in which bromohydrin product is identified as the intermediate and transformed to epoxide with the removal of HBr when meeting OH−.
Journal Article
Differentiation of confluent hepatic fibrosis and infiltrative hepatocellular carcinoma on MR imaging
by
Duan, Meng-jiao
,
Cheng, Jing-liang
,
Wang, Meng-zhu
in
Diagnosis
,
Differentiation
,
Diffusion coefficient
2024
BackgroundTo identify reliable magnetic resonance imaging (MRI) features that can differentiate confluent fibrosis (CF) from infiltrative hepatocellular carcinoma (HCC).MethodsA retrospective analysis was conducted on Twenty CF patients and 28 infiltrative HCC patients who underwent upper abdomen MRI scans. The imaging features of lesions were analyzed, and the apparent diffusion coefficient (ADC) of lesions were measured. Accuracy, sensitivity and specificity for the diagnosis of CF were calculated for each category individually and combined.ResultsCompared to infiltrative HCC, hepatic capsular retraction at the site of lesion, hepatic volume loss at the site of lesion and “nodular surround sign” were more common in patients with CF (all P < 0.001). Hepatic volume loss at the site of lesion, no or mild enhancement in arterial phase, and hyper-enhancing in delayed phase to the background parenchyma showed superior diagnostic accuracy (83.3%, 85.4%, 97.9%, respectively). When the lesion exhibited hepatic volume loss at the site of lesion or no or mild enhancement in arterial phase or hyper-enhancing in delayed phase, a sensitivity of 100.0% for the diagnosis of CF was achieved. When the lesion was positive for any two of three categories, or positive for all three categories, a specificity of 100.0% was achieved. The ADC values of CF were higher than those of infiltrative HCC (P < 0.001).ConclusionThe combination of the hepatic volume loss at the site of lesion, no or mild enhancement in arterial phase, and hyper-enhancing in delayed phase to the background parenchyma can be considered reliable MR features for the diagnosis of CF, as they allow differentiation from infiltrative HCC.
Journal Article
A simple and robust method for calculating temperatures of granitoid magmas
2022
Calculating the temperatures of magmas from which granitoid rocks solidify is a key task of studying their petrogenesis, but few geothermometers are satisfactory. Zircon saturation thermometry has been the most widely used because it is conceptually simple and practically convenient, and because it is based on experimental calibrations with significant correlation of the calculated zircon saturation temperature (TZr) with zirconium (Zr) content in the granitic melt (i.e., TZr ∝ ZrMELT). However, application of this thermometry to natural rocks can be misleading, resulting in the calculated TZr having no geological significance. This thermometry requires Zr content and a compound bulk compositional parameter M of the melt as input variables. As the Zr and M information of the melt is not available, petrologists simply use bulk-rock Zr content (ZrBULK-ROCK) and M to calculate TZr. In the experimental calibration, TZr shows no correlation with M, thus the calculated TZr is only a function of ZrMELT. Because granitoid rocks represent cumulates or mixtures of melt with crystals before magma solidification and because significant amount Zr in the bulk-rock sample reside in zircon crystals of varying origin (liquidus, captured or inherited crystals) with unknown modal abundance, ZrBULK-ROCK cannot be equated with ZrMELT that is unknown. Hence, the calculated magma temperatures TZr using ZrBULK-ROCK have no significance in both theory and practice. As an alternative, we propose to use the empirical equation TSiO2 (°C) = -14.16 × SiO2 + 1723 for granitoid studies, not to rely on exact values for individual samples but focus on the similarities and differences between samples and sample suites for comparison. This simple and robust thermometry is based on experimentally determined phase equilibria with T ∝ 1/SiO2.
Journal Article