ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Xiuhua Li,Guanghui Nie,Jinxiong Tao,Wenjun Wu,Liuchan Wang,Shijun Liao
3,3′-di(4″-methyl-phenyl)-4,4′-difluorodiphenyl sulfone (DMPDFPS), a new monomer with two pendent benzyl groups, was easily prepared by Suzuki coupling reaction in high yield. A series of side-chain type ionomers (PAES-Qs) containing pendant side-chain benzyltrimethylammonium groups, which linked to the backbone by alkaline resisting conjugated C–C bonds, were synthesized via polycondensation, bromination, followed by quaternization and alkalization. To assess the influence of side-chain and main-chain aromatic benzyltrimethylammonium on anion exchange membranes (AEMs), the main-chain type ionomers (MPAES-Qs) with the same backbone were synthesized following the similar procedure. GPC and 1H NMR results indicate that the bromination shows no reaction selectivity of polymer configurations and ionizations of the side-chain type polymers display higher conversions than that of the main-chain type ones do. These two kinds of AEMs were evaluated in terms of ion exchange capacity (IEC), water uptake, swelling ratio, λ, volumetric ion exchange capacity (IECVwet), hydroxide conductivity, mechanical and thermal properties, and chemical stability, respectively. The side-chain type structure endows AEMs with lower water uptake, swelling ratio and λ, higher IECVwet, much higher hydroxide conductivity, more robust dimensional stability, mechanical and thermal properties, and higher stability in hot alkaline solution. The side-chain type cationic groups containing molecular configurations have the distinction of being practical AEMs and membrane electrode assemblies of AEMFCs.
研究领域:
材料科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
COMBUSTION AND FLAME
·
2023
·
IF 4.4
Guanyu Wang,Dan Xu,Jiaqi Tang,Bingzhi Liu,Zhandong Wang,Qiang Xu,Yanjun Hu,Jinsong Zhou,Shurong Wang
As an important component of organic solid wastes, disposal of plastic wastes (PWs) has always been a thorny issue. Thermochemical conversion is an efficient method. In-depth research on the influence of structural differences on their pyrolysis behavior is beneficial to promote the development of thermal treatment and conversion technology of PWs. The differences in the chemical structure of different polyolefin plastics at the molecule level are mainly reflected in their side chains. Herein, a series of typical polyolefin plastics with similar backbone structure and different side chain structures, including high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA) and ethylene-vinyl acetate copolymer (EVA), were selected for comprehensive pyrolysis characterization in this work. Advanced experimental analysis methods such as in-situ DRIFT and 2D-PCIS were adopted to investigate the evolution of two weak oxygen-containing side chains during pyrolysis of PVA and EVA, respectively. Besides, typical product distribution of six samples were systematically studied by combining SVUV-PIMS and GC/MS. Spectral analysis showed that OH side chain in macromolecular structure of PVA had the weakest thermal stability, and its oxidation reaction occurred earlier than dissociation and dehydration, while the acetoxy side chain in EVA polymers could not only be directly dissociated via deacetoxylation, but also be transformed into OH side chain via deacetylation that occurred simultaneously with deacetoxylation. Further combined with SVUV-PIMS and GC/MS, the distribution characteristics of pyrolysis products of polyolefin plastics and the rules of generation and release of typical products with temperature were obtained in detail. It was found that the release of typical oxygen-containing products was earlier or slightly earlier than the release of hydrocarbons in pyrolysis of PVA or EVA. However, the release of all hydrocarbons was almost simultaneous during the respective pyrolysis process of HDPE, PP and PS, suggesting that the evolution of oxygen-containing side chains with weak thermal stability occurred earlier under the drive of temperature. Based on the characterization results, the main evolution pathways of different side chains were proposed to explain the influence mechanism of different side chain structures on the pyrolysis behavior of polyolefin plastics. The cleavage of C C bonds mainly occurred in HDPE, PP and PS, while the evolution of side chains occurred first in PVC, PVA and EVA, and exerted different influence on the degradation of carbon skeleton.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 60
·55479-55489
·
IF 3.289
Xinyuan Che,Shiming Gong,Leishan Shao,Tian Lan,Fei Wang,Yinghan Wang
Two series of polyimides (PIs) which contained identical side chains but different backbones were synthesized from the same functional diamine: RPI-X% and SPI-X% (X = 20, 30, 40, X stands for the molar content of functional diamine). Rigid polyimides (RPIs) are PIs whose backbones are composed of wholly rigid aromatic units and soft polyimides (SPIs) are PIs whose backbones are composed of flexible ether units and aromatic units. The surface morphology, chemical composition and molecular orientation of the polyimide (PI) alignment layer surfaces were investigated by atomic force microscopy, X-ray photo-electron spectroscopy and polarized attenuated total reflection Fourier transformed infrared spectroscopy, respectively. The results showed that both RPI and SPI could induce LC to align vertically without a rubbing process when the molar content of the functional diamine reached 30%. However, the rubbed RPI-30% whose side chains were oriented vertically induced vertical alignment of the liquid crystal (LC), while the rubbed SPI-30% whose side chains were oriented parallel induced parallel alignment of the LC. The cause of this distinction was attributed to the different main chain structures: the wholly rigid aromatic units in RPI's main chains could restrict the movements of molecular chains so the side chains can maintain vertical orientation all the time; flexible ether bands in SPI main chains could endow molecular chains with mobility so the side chains fall over easily after rubbing.
研究领域:
材料科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Sha Liu,Xiaoteng Jiang,Zhi Shang,Yin Ji,Huiyu Wang,Zeyuan Wang,Peng Wang,Yan Zhang,Hua Xiao
Glycoproteins are important biomarkers for cancers, while most glycoproteomics biomarkers suffering from low sensitivity and specificity due to their uncharacterized glycan structures. AZGP1 is a potential biomarker for salivary diagnostics of lung cancer, which is used as a model glycoprotein in this study for method development. We initially analyzed salivary N-glycoproteome by using lectin affinity chromatography and more than 300 N-glycoproteins were identified, including AZGP1. 7 gel spots of AZGP1 were resolved by two-dimensional gel electrophoresis and further confirmed by two-dimensional western blot as well as mass spectrometry. The isomeric glycan structures of AZGP1 in these spots were systematically characterized both at composition level and at structure level. Our results revealed 10 glycan compositions for salivary AZGP1, including core fucosylated glycans on Asn128 and sialylated glycans on Asn109 and Asn112. We further compared the glycan structures of salivary AZGP1 from lung cancer group and control group. Accordingly, 14 and 7 potential glycan structures were successfully revealed, respectively. In total, 15 glycan compositions and 22 potential glycan structures were identified and characterized for AZGP1, including some different structures with the same compositions. In particular, 5 potential glycan structures were identified as lung cancer unique signatures. Our developed strategy holds promise for thorough identification of glycan structures on a target glycoprotein biomarker. In-depth characterization of its glycan structures will ultimately enhance its sensitivity and specificity for cancer detection.
研究领域:
生物化学
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癌症研究
·
蛋白质组学
✓ 已验证
DOI
PubMed
高影响因子
Chemistry-Switzerland
·
2023
·Vol. 5
·期 3
·1497-1507
·
IF 2.1
Longlong Gao,Rui Tian,Yong Shao
DNAzymes have attracted increasing interest in developments of gene tools, therapies, and biosensors. Among them, G-quadruplexes are widely used as the key structure elements of DNAzymes to activate the catalytic competency of specific cofactors, such as hemin, but there is a great demand to diversify DNAzymes using other more straightforward DNA structures such as fully matched duplex (FM-DNA). However, the perfect base pairs in duplex limit the DNAzyme activity. In this work, a photocatalytic DNAzyme was developed by introducing an abasic site (AP site) into duplex (AP-DNA) to switch its photocatalytic activity. Palmatine (PAL), a photosensitizer from natural isoquinoline alkaloids, served as a cofactor of the DNAzyme by binding at the AP site. The AP site provides a less polarized environment to favor the PAL fluorescence. As a result, dissolved oxygen was converted into singlet oxygen (1O2) via energy transfer from the excited PAL. The oxidation of substrates by the in situ photogenerated1O2served as a readout for the DNAzyme. In addition, the duplex-based DNAzyme was engineered from FM-DNA by the cascade uracil-DNA glycosylase to generate AP-DNA. Our work provides a new way to construct duplex-based DNAzymes.Keywords:DNAzyme;duplex;abasic site;phohocatalysis;isoquinoline alkaloids;palmatine
研究领域:
生物化学
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分子生物学
·
催化
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产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Haoran Xu,Sheng Chen,Shaonan Chen,Rui Qiao,Hui Li,Hang Luo,Dou Zhang
When one considers that outstanding dielectric polymers satisfy the developed requirements in the electronic and electrical industries, it is necessary to explore the structure–property relationship of all-organic polymer dielectrics. In this paper, two kinds of side-chain sulfonyl-containing dipolar polymers based on polyolefin main chains, poly{2,5-bis[(4-(methylsulfonyl)phenyl)oxycarbonyl]styrenes} (PBSO2) and poly{2,5-bis[(4-(methylsulfonyl)ethyl)oxycarbonyl]styrenes} (PESO2), were prepared via radical polymerization. The effect of the side-chain structure on the phase behavior, phase structure, dielectric property, and energy storage of dipolar polymers was investigated. The results showed that PBSO2 possessed a high glass transition temperature (Tg ≈ 195 °C) and formed the columnar nematic phase owing to the rigid side-chain structure. A dielectric constant of 20.8 (25 °C, 103 Hz) was obtained for the polymer PBSO2 due to the highly orientational polarization and the possible interfacial polarization between the amorphous phase and liquid crystalline phase, which is 18% higher than that of PESO2. However, PBSO2 exhibited a low breakdown strength because of the low band gap of ≈3.46 eV and brittleness of the film. In contrast, a low Tg of 78 °C and isotropic phase were found in the polymer PESO2. In addition, a discharge energy density of 6.2 J/m3 at 270 MV/m was achieved, which was attributed to the high dipole density. This study indicates that it is effective to improve the dielectric constant by introducing a liquid crystalline phase into a dipolar polymer, which offers a route for synthesizing high-performance dielectric polymers.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
BIOPHYSICAL JOURNAL
·
2022
·
IF 3.699
Shen Wang,Cong Ma
Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) form the SNARE complex to mediate most fusion events of the secretory pathway . The neuronal SNARE complex is featured by its high stability and half-zippered conformation required for driving robust and fast synaptic exocytosis. However, these two features seem to be thermodynamically mutually exclusive. In this study, we have employed temperature-dependent disassociation assays and single-molecule Förster resonance energy transfer (FRET) experiments to analyze the stability and conformation of the neuronal SNARE complex. We reclassified the amino acids of the SNARE motif into four sub-groups (core, core-side I and II, and non-contact). Our data showed that the core residues predominantly contribute to the complex stability to meet a basal requirement for SNARE-mediated membrane fusion , while the core-side residues exert an unbalanced effect on the N- and C-half bundle stability that determines the half-zippered conformation of the neuronal SNARE complex, which would accommodate essential regulations by complexins and synaptotagmins for fast Ca 2+ -triggered membrane fusion. Furthermore, our data confirmed a strong coupling of folding energy between the N- and C-half assembly of the neuronal SNARE complex, which rationalizes the strong potency of the half-zippered conformation to conduct robust and fast fusion. Overall, these results uncovered that the stability profile of the neuronal SNARE complex reflects its potency to drive fast and robust membrane fusion. Based on these results, we also developed a new parameter, the stability factor ( F s ), to characterize the overall stability of the neuronal SNARE complex and resolved a linear correlation between the stability and inter-residue coulombic interactions of the neuronal SNARE complex, which would help rationally design artificial SNARE complexes and remold functional SNARE complexes with desirable stability.
研究领域:
细胞生物学
·
生物物理学
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2022
·
IF 6.959
Yiyuan Ding,Xin Ren,Dong Chen,Fanjue Wen,Ting Li,Fei Xu
Rechargeable Mg batteries have the advantages of abundant reserves and high safety, but suitable inorganic cathodes are quite limited. Organic polymers break the hindrance of the inorganic Mg-storage crystal lattice and provide more selections, but the reports on organic rechargeable Mg battery cathodes are relatively few. Herein, high-capacity bipolar organic cathodes are developed for rechargeable Mg batteries. Poly(1,5-diaminoanthraquinone) with double polyaniline chains is used as a bipolar cathode. The carbonyl and amino groups are employed as the N-doping and P-doping centers, respectively, and the conjugated anthraquinone unit delocalizes the charge density change during the redox reactions. Considering the mass of Mg salt, the poly(1,5-diaminoanthraquinone) cathode provides a high corrected capacity of 267 mA h g–1 (non-corrected capacities of 297 mA h g–1) for bipolar reactions. Moreover, compared with the single-chained poly(1-aminoanthraquinone) (44% capacity maintained after 140 cycles), the double-chained poly(1,5-diaminoanthraquinone) shows a much better N-doping cycleability (97% capacity maintained after 300 cycles), as the double polyaniline chains enhance the structure stability during the Mg-storage reaction. The present study demonstrates the importance of a large conjugated double-chain structure to enhance the Mg-storage performance of organic polymers. It is also imagined that the bipolar organic materials with both of N- and P-dopings are a highly promising strategy for development of high-capacity organic Mg battery cathodes.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2023
·Vol. 140
·期 19
·e53829
·
IF 3
Xin Kang Li,Jun Wei Shen,Hai Lan Lin,Zhao Xin Zhang,Xun Tao Zhang,Jun Bian,Dai Qiang Chen
In order to explore effective strategies to fabricate main-chain polybenzoxazine (PBZ) thermosetting resin for structural material applications, here, five PBZ with different molecular structures, that is, poly(Co-ddm), poly(Co-BPA-ddm-Co) main , poly(Ph-BPA-ddm-Co) main , poly(Ph-BPA-ddm-Ph) main and poly(Ph-ddm) were designed, synthesized and compared by introducing unsaturated fatty chains through the Mannich reaction with cardanol. The structure and properties of five PBZ with different structure were systematically investigated by using Fourier transform infrared (FTIR), NMR, water absorption and mechanical tests. FTIR and NMR tests indicated that five PBZ with different molecular structures were successfully synthesized. The mechanical tests indicated that the impact strength of the double-capped cardanol-based main-chain PBZ was 243% higher than that of the traditional PBZ. The water absorption of main-chain PBZ was higher than that of diamine PBZ, and the water absorption of poly(Ph-BPA-ddm-Co) main was the lowest in the main-chain PBZ. Based on the experimental results, five PBZ amorphous cells with different structures were successfully established. It indicated that the main chain PBZ showed better thermomechanical properties than the traditional diamine PBZ due to high crosslinking conversion and hydrogen bond density. Moreover, the modulus and glass transition temperature of the main chain structure containing unsaturated fatty chains did not decrease significantly.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Food Bioscience
·
2024
·
IF 4.8
Xiaoqiang Zou,Mudassar Hussain,Imad Khan,Yanxi Wang,Bangzhi Jiang,Lei Zheng,Yuechao Pan,Jijie Hu,Azqa Ashraf
Medium- and long-chain structured lipids (MLSLs) rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were synthesized by acidolysis of fish oil (Omax 1812, a mixture of sardine and anchovy oils) with caprylic acid (CA) using a lipase bio-imprinted with fatty acids as a catalyst. A bio-imprinted lipase for the acidolysis reaction was first prepared under optimal conditions, and its activity was 1.43 times higher than that of the non-bioimprinted. The bio-imprinted lipase was used as a catalyst to produce such MLSLs, and the reaction conditions were optimized. Under the optimal conditions, equilibrium was achieved in 8 h, and the total and the sn -1, 3 CA contents in the obtained product were 28.72% and 42.26%. Additionally, the total and the sn -2 DHA contents were 14.23% and 21.10%, respectively, and the total and the sn -2 EPA contents were 16.43% and 10.14%, respectively. These obtained MLSLs, rich in sn -1, 3 CA, and sn -2 DHA, EPA can deliver significant health benefits.
研究领域:
生物化学
·
食品科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMBIOCHEM
·
2020
·Vol. 21
·期 18
·2667-2675
·
IF 2.576
Mengjia Xu,Pan Fu,Shu Xing,Yang Zhao,Chao Zhao
Graphical Point-of-care cancer catching ? A novel PNA-DNA 2 triplex consisting of a homopurine PNA strand and two homopyrimidine DNA strands is reported for the first time. On the basis of this phenomenon, a simple, inexpensive colorimetric PNA-DNA 2 triple-helix molecular switch-based sensing platform for sensitive and selective detection of miRNAs from cancer cells is demonstrated. Peptide nucleic acids (PNAs), the synthetic DNA mimics that can bind to oligonucleotides to form duplexes, triplexes, and quadruplexes, could be advantageous as probes for nucleic acid sequences owing to their unique physicochemical and biochemical properties. We have found that a homopurine PNA strand could bind to two homopyrimidine DNA strands to form a PNA-DNA 2 triplex. Moreover, the cyanine dye DiSC 2 (5) could bind with high affinity to this triplex and cause a noticeable color change. On the basis of this phenomenon, we have designed a label-free colorimetric sensing platform for miRNAs from cancer cells by using a PNA-DNA 2 triple-helix molecular switch (THMS) and DiSC 2 (5). This sensing platform can detect miRNA-21 specifically with a detection limit of 0.18 nM, which is comparable to that of the THMS-mediated fluorescence sensing platform. Moreover, this colorimetric platform does not involve any chemical modification or enzymatic signal amplification, which boosts its applicability and availability at the point of care in resource-limited settings. The universality of this approach can be simply achieved by altering the sequences of the probe DNA for specific targets.
研究领域:
分子生物学
·
医学诊断
·
分析化学
✓ 已验证
DOI
高影响因子
DESIGNED MONOMERS AND POLYMERS
·
2015
·
IF 2.78
Yaobin Liu,Zhiqiang Fan
A novel radical addition-coupling polymerization method is applied to prepare gels with controlled chain structure and length between branch points. Structure of the chains was varied between rigid or flexible ones by synthesizing different tribromide and dibromide monomers and reacting them with 2-methyl-2-nitrosopropane (MNP) under catalysis of Cu/N,N,N′,N′′,N′′-pentamethyldiethylene-triamine. The carbon radical generated by single electron transfer from the bromides can be efficiently captured by MNP, forming nitroxide radical. The in situ formed nitroxide radical immediately undergoes cross-coupling reaction with another carbon radical, generating gel bridged with alkoxyaime moiety via step-growth mechanism. The tribromide and dibromide monomers were synthesized from different saturated and unsaturated compounds, or by bulk atom transfer radical polymerization of styrene using small bromide as initiator. The rigid gel has better controlled chains between branch points than the flexible ones. Selective dissociation of the ester group in the backbone of chains has been realized, which reserved the weak of NO–C. Flory–Huggins interaction parameter χ of the gels with fixed length between branch points were measured, which solved the difficulty that χ of insoluble polymer cannot be determined by common methods used for soluble polymers.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）