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Now showing items 97 - 112 of 148

  • Polymeric ionic liquids tailored by different chain groups for the efficient conversion of CO2 into cyclic carbonates

    Ying, Ting   Tan, Xin   Su, Qian   Cheng, Weiguo   Dong, Li   Zhang, Suojiang  

    To realize a high utilization ratio and easy recyclability of catalysts, polymeric ionic liquids as heterogeneous catalysts are tailored for the transformation of CO2 into cyclic carbonates. Herein, six types of self-polymerized polymeric ionic liquids are successfully synthesized by changing the substitutions. Amongst those catalysts, hydroxyl-rich polymeric ionic liquids, especially P(DMAEMA-EtOH)Br, exhibit the highest conversion (96%) to propyl carbonate, which is almost comparable to the reactivity of the bulk ionic liquid. Not only does the presence of a hydroxyl group considerably boost the reactivity, but it also enhances the thermal stability. Molecular dynamics calculations and XPS analysis confirm that the ability of P(DMAEMA-EtOH) Br to combine with epoxide is equivalent to that of its monomer. Dynamic light scattering data reveal that decreasing the hydrodynamic radius of the polymer particles contributes to greater exposure of active sites, resulting in high reactivity. In addition, synergistic catalysis mechanisms are proposed on the basis of the H-NMR studies. This eco-friendly process using polymeric ionic liquids provides a promising catalyst to convert CO2 into value-added chemicals.
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  • Treadmill rehabilitation treatment enhanced BDNF-TrkB but not NGF-TrkA signaling in a mouse intracerebral hemorrhage model

    Chen, Jie   Qin, Jie   Su, Qian   Liu, Zhixue   Yang, Jian  

    Intracerebral hemorrhage (ICH), accounting for 15-20% of strokes, can cause significant brain injury and life long neurological deficits. We investigated whether treadmill exercise rehabilitation could improve brain repair after ICH and whether involvement of NFG-TrkA and BDNF-TrkB signaling could be observed during repair period in an experimental mouse ICH model reproduced by heparinized-collagenase infusion into the left caudate putamen. 5-Bromo-2-deoxyuridine (BrdU) labeled new dividing cell can be observed clearly around the injured cortex and striatum region on day 7 (D7) after operation, and both TrkA and TrkB neurotropic receptors were activated. A subgroup of these ICH mice began the treadmill exercise from D4 after operation. Then we found that the overall immunofluorescent signals of p-Y490-TrkA and p-Y705-TrkB were both decreased in all groups at 014 after operation. However, compared to the non-exercise ICH group mouse, the immunofluorescent intensity of BDNF and p-Y705-TrkB were significantly higher in the exercise group. In addition, there was no difference in p-Y490-TrkA. Our results suggest that BDNF-TrkB but not NGF-TrkA signaling is involved in the brain repair after ICH, and early proper treadmill exercise might promote this repair process. (C) 2012 Elsevier Ireland Ltd. All rights reserved.
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  • Evaluation on the dynamic performance of bridge approach backfilled with fibre reinforced lightweight concrete under high-speed train loading

    Liu, Kaiwen   Su, Qian   Ni, Pengpeng   Zhou, Chuanbin   Zhao, Wenhui   Yue, Fei  

    In China, high-speed rails are often constructed over bridges in the region of soft soils. Differential settlement could occur in the foundation soils between bridge abutment and approach embankment that causes "bumps" to affect the smoothness at the end of a bridge. A three-dimensional finite element model is developed to investigate the use of fibre reinforced lightweight concrete in the transition zone of bridge approach for high-speed railways. Time-frequency analysis is performed using the method of Fast Fourier transform. The sensitivity analysis of rail speed, density of backfills, and the structural type of the trapezoidal shaped transition zone is conducted.
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  • Boron-doped melamine-derived carbon nitrides tailored by ionic liquids for catalytic conversion of CO2 into cyclic carbonates

    Su, Qian   Yao, Xiaoqian   Cheng, Weiguo   Zhang, Suojiang  

    A new approach to tailoring edge active groups of graphitic carbon nitrides for catalytic conversion of CO2 into cyclic carbonates was proposed in this work. To improve the catalytic performance, boron-doped melamine-derived graphitic carbon nitrides (MCNB) with numerous exposed edge defects were prepared by using 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF(4)) as the soft template and boron source. Different mass ratios of BmimBF(4) to melamine were explored for MCNB preparation, MCNB(x) (x is the mass ratio) with different polymerization degree, pore structure and boron doping content were obtained, and the relationship between MCNB properties and the corresponding catalytic activity was then investigated. With low polymerization degree, abundant meso-macroporous structure and small amounts of boron (<1.59 atm%) doped in the skeleton, MCNB(0.01) exhibited better catalytic performance and could be suitable for various epoxide substrates with the yield of cyclic carbonates up to 89.0% at 130 degrees C in 6 h. According to the XPS analysis and DFT calculation results, the active centers were confirmed to be the partially-condensed amino groups in edge defects, which were enhanced by moderate doping of boron in the skeleton.
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  • Elevated serum complement C3 levels are associated with prehypertension in an adult population

    Bao, Xue   Meng, Ge   Zhang, Qing   Liu, Li   Wu, Hongmei   Du, Huanmin   Shi, Hongbin   Xia, Yang   Guo, Xiaoyan   Liu, Xing   Han, Peipei   Dong, Renwei   Wang, Xiuyang   Li, Chunlei   Su, Qian   Gu, Yeqing   Fang, Liyun   Yu, Fei   Yang, Huijun   Kang, Li   Ma, Yixuan   Yu, Bin   Ma, Xinyu   Sun, Shaomei   Wang, Xing   Zhou, Ming   Jia, Qiyu   Guo, Qi   Song, Kun   Wang, GuoLin   Huang, Guowei  

    Prehypertension is a public health epidemic associated with various adverse outcomes, but can be reversed by timely intervention. However, little attention has been paid to prehypertension. Complement C3 is a central hub of complement-related immune system. We examined the association between C3 and prehypertension in an adult population for the first time, aiming to investigate whether pro-inflammatory immune response is involved in the prehypertensive state. About 7820 Tianjin residents without hypertension were categorized into sex-specific quintiles based on their serum concentration of complement C3. Adjusted logistic regression models were used separately by gender to assess the association between C3 quintiles and the prevalence of prehypertension. After multiple adjustment, the odds ratios (95% confidence interval) for prehypertension across increasing quintiles of C3 were 1.00 (reference), 1.02 (0.84, 1.25), 1.15 (0.94, 1.42), 1.25 (1.01, 1.54), and 1.71 (1.35, 2.17) (p for trend < 0.0001) among men and were 1.00 (reference), 1.17 (0.92, 1.49), 1.13 (0.88, 1.44), 1.15 (0.89, 1.48), and 1.40 (1.07, 1.84) (p for trend =3D 0.03) among women. The findings suggested that elevated serum C3 levels are associated with prehypertension. Reducing inflammation may be a potential therapeutic strategy for prehypertension and hypertension that is worthy of further studies and discussion.
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  • Dietary patterns are associated with depressive symptoms among Chinese adults: a case-control study with propensity score matching.

    Xia, Yang   Wang, Na   Yu, Bin   Zhang, Qing   Liu, Li   Meng, Ge   Wu, Hongmei   Du, Huanmin   Shi, Hongbin   Guo, Xiaoyan   Liu, Xing   Li, Chunlei   Han, Peipei   Dong, Renwei   Wang, Xiuyang   Bao, Xue   Su, Qian   Gu, Yeqing   Fang, Liyun   Yu, Fei   Yang, Huijun   Kang, Li   Ma, Yixuan   Sun, Shaomei   Wang, Xing   Zhou, Ming   Jia, Qiyu   Guo, Qi   Wu, Yuntang   Song, Kun   Niu, Kaijun  

    PURPOSE: Previous studies have indicated that consumption of particular foods or nutrients is associated with depressive symptoms, but little is known about the role of overall dietary patterns in depressive symptoms. We design this case-control study to evaluate the associations between dietary patterns and high depression symptoms in Chinese adults.; METHODS: A total of 1351 participants with high depressive symptoms were matched with 1351 controls using the 1:1 ratio propensity score matching method. Dietary intake was assessed using a valid self-administered food frequency questionnaire, and high depressive symptoms were assessed with the Zung Self-Rating Depression Scale, wherein cutoff point of 45 was used as a definition of high depressive symptoms.; RESULTS: Exploratory factor analysis revealed three dietary patterns (vegetables and fruits pattern; sweets pattern; and animal foods pattern) explaining 25.1% of the total variance. Compared with the participants in the lowest quartile, the participants in the highest quartile of vegetables and fruits pattern, which was defined as a healthy pattern, were associated with reduced odds of high depressive symptoms (OR 0.65, 95% CI 0.52-0.83, P for trend <0.001) while the sweets pattern (OR 1.33, 95% CI 1.06-1.66) and the animal foods pattern (OR 1.79, 95% CI 1.43-2.24, P for trend <0.0001) were associated with increased prevalence of high depressive symptoms, respectively.; CONCLUSION: The present study adds to the evidence that the sweets pattern and animal foods pattern are positively associated with the prevalence of high depressive symptoms. In contrast, the dietary pattern rich in vegetables, fruits, and soya bean products, but low in animal foods, candied fruits, cakes, ice cream, sugared beverages, and alcoholic drinks is negatively associated with the prevalence of high depressive symptoms.=20
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  • Effects of imidazolium-based ionic liquids on the isobaric vapor-liquid equilibria of methanol plus dimethyl carbonate azeotropic systems

    Chen, Songsong   Dong, Li   Zhang, Junping   Cheng, Weiguo   Huo, Feng   Su, Qian   Hua, Wei  

    The separation of methanol (MeOH) and dimethyl carbonate (DMC) is important but difficult due to the formation of an azeotropic mixture. In this work, isobaric vapor-liquid equilibrium (VLE) data for the ternary systems containing different imidazolium-based ionic liquids (ILs), i.e. MeOH + DMC + 1-butyl-3-methy-limidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmim][Tf2N]), MeOH + DMC + 1- ethyl-3-methyl-imidazolium bis [( trifluoromethyl)sulfonyl]imide ([Emim][Tf2N]), and MeOH + DMC + 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6])) were measured at 101.3 kPa. The mole fraction of IL was varied from 0.05 to 0.20. The experimental data were correlated with the NRTL and Wilson equations, respectively. The results show that imidazolium-based ILs were beneficial to improve the relative volatility of MeOH to DMC, and [Bmim][Tf2N] showed a much more excellent performance on the activity coefficient of MeOH. The interaction energies of system componentswere calculated using Gaussian program, and the effects of cation and anion on the separation coefficient of the azeotropic system were discussed. (C) 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.
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  • Oxidative Stress Induces Neuronal Apoptosis Through Suppressing Transcription Factor EB Phosphorylation at Ser467.

    Su, Qian   Zheng, Bin   Wang, Chen-Yao   Yang, Yun-Zhi   Luo, Wen-Wen   Ma, Shu-Min   Zhang, Xin-Hua   Ma, Dong   Sun, Yan   Yang, Zhan   Wen, Jin-Kun   Liu, Zhi-Xue  

    BACKGROUND/AIMS: This study determined the role and mechanism of action of transcription factor EB (TFEB) in H2O2-induced neuronal apoptosis.; METHODS: SH-SY5Y cells were treated with Akt inhibitor/activator and different concentrations of H2O2. Cell apoptosis was detected by flow cytometric analysis. Akt and TFEB phosphorylation and PARP cleavage were determined by Western blotting. HEK293T cells were transfected with different truncated TFEB mutants and HA-Akt-WT; SH-SY5Y cells were transfected with Flag-vector, Flag-TFEB, Flag-TFEB-S467A or Flag-TFEB-S467D; and TFEB interaction with Akt was determined by co-immunoprecipitation and GST pull-down assays.; RESULTS: A low concentration of H2O2 induces TFEB phosphorylation at Ser467 and nuclear translocation, facilitating neuronal survival, whereas a high concentration of H2O2 promotes SH-SY5Y cell apoptosis via suppressing TFEB Ser467 phosphorylation and nuclear translocation. The TFEB-S467D mutant is more easily translocated into the nucleus than the non-phosphorylated TFEB-S467A mutant. Further, Akt physically binds to TFEB via its C-terminal tail interaction with the HLH domain of TFEB and phosphorylates TFEB at Ser467. Mutation of TFEB-Ser467 can prevent the phosphorylation of TFEB by Akt, preventing inhibition of oxidative stress-induced apoptosis.; CONCLUSIONS: Oxidative stress induces neuronal apoptosis through suppressing TFEB phosphorylation at Ser467 by Akt, providing a novel therapeutic strategy for neurodegenerative diseases. =C2=A9 2018 The Author(s). Published by S. Karger AG, Basel.
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  • Effect of 1,4-cyclohexanediol on percutaneous absorption and penetration of azelaic acid

    Li, Nan   Su, Qian   Tan, Fengping   Zhang, Jerry  

    The objective of this study is to investigate the effect of 1,4-cyclohexanediol as a retardant on the percutaneous absorption and penetration of azelaic acid. Hairless Fat skin was mounted on Franz diffusion cells and treated with topical formulations containing solubilized azelaic acid with and without 1,4-cyclohexanediol. The skin was separated into stratum corneum and the deeper skin layers. The azelaic acid collected in receptor medium and each layer at the end of each time point was extracted and quantified. A significant decrease in flux across the skin suggests a penetration retardation effect of 1,4-cyclohexanediol (42.50 mu g/cm(2)/h in the presence of vs. 76.25 mu g/cm(2)/h in the absence of) at active loading level of 1.13 mg/cm(2). The penetration retardation effect was also observed at higher active loading level (2.82 mg/cm(2)). Furthermore, presence of 1,4-cyclohexanediol in the topical formulation did not reduce the skin and epidermal retention of azelaic acid, suggesting its potential use in the development of superior topical formation for reducing potential systematic side effect while maintaining therapeutic efficiency. (C) 2009 Elsevier B.V. All rights reserved.
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  • Composition and characteristics of continuous enzymatic hydrolysis products from Kappaphycus striatum

    Yu, Yuan   Yang, Min   Yang, Jing   Su, Qian   Mou, Haijin  

    The oligosaccharide kappa-carrageenan is sulfated carbohydrate with various bioactivities. In order to prepare this functional oligosaccharide directly from the red alga Kappaphycus striatum, a continuous enzymatic hydrolysis method was used to digest K. striatum. The yield of oligosaccharide (product KS-3) reached 43.26 g per 100 g of dry algae, and the product was identified as high-purity sulfated oligosaccharides mainly composed of kappa-carrageenan hexasaccharide ([A-G(4S)](3)) and octasaccharide ([A-G(4S)](4)). The by-products generated during the preparation of oligosaccharide were also collected. The yield of insoluble product (KS-1) was 14.46 g per 100 g of dry algae, it was rich in protein (63.23%) and the content of essential amino acid was close to 40 g per 100 g of dry protein. The yield of soluble high-molecular weight product (KS-2) was 18.04 g per 100 g of dry algae, it was mainly composed of soluble dietary fibers (69.49%) and showed perfect expansion characteristics. We describe here a novel method for the preparation of oligosaccharides directly from seaweed, which is also beneficial for the comprehensive utilization of seaweed.
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  • Ultimate Capacity Analysis and Determination of the Position of Failure Surface for Uplift Piles

    Su, Qian   Zhang, Xiaoxi   Yin, Pingbao   Zhao, Wenhui  

    Ultimate capacity and failure surface position of uplift piles are dependent on soil parameters. In this paper, the horizontal slice method is used to discuss the relation among the ultimate uplift capacity, the failure surface position, and soil parameters with Mohr-Coulomb failure criterion. According to the limit equilibrium analysis, the ultimate uplift capacity is calculated by dividing soil around the pile into slices with considering the potential failure surface as a group of several sectional planes. Then the multivariate function used to calculate ultimate capacity is established and optimized by the sequential quadratic programming. Through the numerical calculation and comparison with the previous research, the results show that the method is reasonable and effective and can be used to determine the failure surface and the magnitude of the ultimate capacity of uplift piles.
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  • Long-term reinforcement strains for column supported embankments with viscous reinforcement by FEM

    Liu, K. -W.   Rowe, R. Kerry   Su, Qian   Liu, Bao   Yang, Zhixiang  

    The time-dependent performance of deep-mixing-method column supported embankments reinforced by viscous reinforcement is investigated for different long-term (at 99% degree of consolidation) reinforcement strains using fully coupled three-dimensional finite element method. The influence of longterm reinforcement strains on long-term net embankment height, maximum crest settlement, maximum differential settlement at the crest and horizontal toe movement of embankments numerically constructed over two soft foundations is explored with the consideration of viscosity of two reinforcement products. Based on a series of numerical simulations, an approach to controlling the deformations of column supported embankments to modest levels while maximizing their long-term service heights is proposed. Also, a correlation between long-term reinforcement strain and end-of consolidation reinforcement strain is suggested for the studied cases. (C) 2017 Elsevier Ltd. All rights reserved.
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  • The Fabrication of Micro-Array Channels with the Ultrafine-Grained LZ91 Mg-Li Alloy by Micro-Embossing

    Su, Qian   Xu, Jie   Wang, Chenxi   Shan, Debin   Guo, Bin  

    The fabrication of the micro-channel array through micro-embossing on an ultrafine-grained (UFG) LZ91 Mg-Li alloy was investigated in this paper. Micro-embossing tests indicated that the depth of the channels increase with increasing temperatures. Micro-array channels with widths ranging from 50 m to 200 m were performed with an applied force of 2 kN at 423 K, following by a dwell time of 60 s on the UFG LZ91 Mg-Li alloy. The surface topography indicates that embossed micro-channels for UFG LZ91 Mg-Li with all widths are clearly printed well with good geometrical transferability and no obvious defects. The comparison filling behavior of UFG and the CG LZ91 Mg-Li alloy reveals that grain sizes mainly affect the filling quality of micro-embossing. The results indicate a potential application of the UFG Mg-Li alloy in the mass fabrication of micro-electro-mechanical system (MEMS) components.
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  • Concise and Gram-Scale Total Synthesis of Lansiumamides A and B and Alatamide.

    Lin, Ran   Lin, Xi   Su, Qian   Guo, Binbin   Huang, Yanqin   Ouyang, Ming-An   Song, Liyan   Xu, Huiyou  

    The total synthesis of potent anti-obesity lansiumamide B was accomplished in four steps using commercially available materials. The synthetic strategy, featured with copper-catalyzed Buchwald coupling, is concise, convergent, practical and can be carried out on a one-gram scale. This approach could give either Z- or E-configured enamide moiety in natural products with absolute stereocontrol and was applied in the total synthesis of natural products.=20
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  • Study on scaling of mechanically alloyed and hot pressed NbCr2 Laves phase at 1200 degrees C in air

    Zheng, Hazhong   Lu, Shiqlang   Su, Qian   Quan, Feijuan  

    Scaling behavior of NbCr2 Laves phase alloys was investigated at 1200 degrees C in air. The specimens were prepared by hot pressing at 1250 degrees C for 30 min from mechanically alloyed (MA, 20 h) powders. The scale morphology was observed by SEM and scale compositions were studied by EDS and scale phases were determined by XRD. It was found that the oxide scale had a structure of two layers: the outer layer was a porous, loosely adherent Cr2O3 layer with 8-10 mu m; the inner layer consisted of CrNbO4 with 50 mu m. And there were one or more breakdowns and wrinkling whereas no spallation in the scale during air cooling to room temperature. TEM analysis indicated that the grain size of the as-HPed NbCr2 Laves phase was 90-200 nm, which enhanced the metal ion diffusion outward and oxygen ion diffusion inward. The results of the present study form a theoretical and technical basis for the further research. (C) 2007 Elsevier Ltd. All rights reserved.
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  • The Dining Cryptographer Problem-Based Anonymous Quantum Communication via Non-maximally Entanglement State Analysis

    Shi, Ronghua   Su, Qian   Guo, Ying   Huang, Dazu  

    We demonstrate an anonymous quantum communication (AQC) via the non-maximally entanglement state analysis (NESA) based on the dining cryptographer problem (DCP). The security of the present AQC is ensured due to the quantum-mechanical impossibility of local unitary transformations between non-maximally entanglement states, which provides random numbers for the secure AQC. The analysis shows that the DCP-based AQC can be performed without intractability through the NESA in the multi-photon entangled quantum system.
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