POLYMER
·
2019
·
IF 3.771
Qingchi Ma,Li Han,Hongwei Ma,Pibo Liu,Heyu Shen,Lincan Yang,Chao Li,Xinyu Hao,Yang Li
Alternating copolymers consisting of a kind of mild electron-withdrawing 1,1-diphenylethylene (DPE) derivative and di-olefins, such as 1,1-bis(4-dimethylsilylphenyl)ethylene (DPE-2SiH) and isoprene (Ip), were successfully synthesized via anionic copolymerization using N,N,N′,N′ -tetramethylethylenediamine (TMEDA) as the modifier and benzene as the solvent. Two mild electron-withdrawing groups (binary -SiH) existed in this system. Therefore, the reaction activity of DPE-2SiH was higher than that of dimethyl-[4(1-phenylvinyl)phenyl]silane (DPE-SiH), and DPE-2SiH was expected to be an appropriate co-monomer for polymerization with dienes. The addition of TMEDA was found to not only control the resulting sequence but also regulate the contents of cis- and trans- structures in the Ip units. To further explore the mechanism of polymerizing DPE-2SiH and isoprene with and without the use of the TMEDA additive, the target samples were carefully characterized by SEC, 1 H NMR and in situ 1 H NMR. By examining the results, the apparent rate constants of DPE-2SiH and Ip without TMEDA were 1.19 × 10 −3 min −1 and 1.29 × 10 −2 min −1 , respectively, while those of DPE-2SiH and Ip with TMEDA were 4.47 × 10 −5 min −1 and 3.05 × 10 −5 min −1 , respectively. The reactivity ratios r Ip of isoprene with and without TMEDA were also calculated by the least square method and found to be 0.65 and 4.21, respectively, which illustrates the mechanisms of the copolymerization of DPE-2SiH and isoprene. By investigating the mechanism of the copolymerization process, the sequence can be controlled the alternating copolymerization, which can be facilely realized in a nonpolar solvent through the use of TMEDA. The alternating copolymers using this method have great significance both to regulation method of the microstructure of isoprene units and to the industrial production of functionalized materials. Then the alternating copolymers of DPE-2SiH and Ip were also applied to synthesize centipede-shaped grafted poly(isoprene)s (PIps). For the existence of bilateral -SiH groups in the chain, hydrosilylation of -SiH and alkynyl groups was performed at room temperature to avoid the unexpected reaction of the -SiH and alkenyl groups from the PIp branches.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
TETRAHEDRON-ASYMMETRY
·
2010
·
IF 2.625
Zhen-Wei Zhang,Gui Lu,Miao-Miao Chen,Ning Lin,Yong-Bo Li,Tamio Hayashi,Albert S.C. Chan
The first asymmetric Mannich-type reaction of methyl isocyanoacetate with N -sulfonylimines catalyzed by cinchona alkaloid derivatives yielded 2-imidazolines with high diastereoselectivities and good enantioselectivities (up to >99:1 dr and 70% ee). This reaction provided a convenient route to access various substituted 2-imidazoline-4-carboxylates and related α,β-diamino acids in high enantiomeric purities.
研究领域:
有机化学
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药物化学
·
不对称合成
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催化化学
·
生物有机化学
✓ 已验证
DOI
高影响因子
Bioresource Technology Reports
·
2018
·
IF 0
Bing-Qian Wang,Bo Peng,Jian-Fei Sun,Chu Wang,Ke Jiang,Jing-Hao Ma,Peng-Qi Zhang,Yu-Cai He
An effecti v e combination pretreatment of bamboo shoot shell (BSS) using Emulsifier OP-10 (0.5%, w/v) in the acidified media (pH 4.0) by autoclaving (120 °C, 40 min) was conducted. After BSS slurry without detoxification was enzymatically hydrolyzed for 96 h, glucose (25.2 g/L) and xylose (7.5 g/L) were obtained from 50 g/L BSS at high yields. HPLC results showed that no potential inhibitors (furfural and 5-hydroxymethylfurfural) formed. In the hydrolysates , an effective biocatalytic synthesis of ethyl ( S )-4-chloro-3-hydroxybutanoate (100% yield; >99% e.e. ) from 1000 mM ethyl 4-chloro-3-oxobutanoate was developed without the extra addition of cofactors within 24 h. In summary, this combination strategy involving biomass pretreatment, enzymatic saccharification , and bioreduction can be developed for producing chiral alcohols.
研究领域:
生物质预处理
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酶解糖化
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生物催化
·
手性醇合成
✓ 已验证
DOI
JOURNAL OF CHROMATOGRAPHY A
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2015
·
IF 4.169
Kexin Hou,Fengli Chen,Yuangang Zu,Lei Yang
An efficient method for the extraction of vitexin , vitexin-4″- O -glucoside, and vitexin-2″- O -rhamnoside from Phyllostachys edulis leaves comprises heat treatment using an ionic liquid–lithium salt mixture (using 1-butyl-3-methylimidazolium bromide as the solvent and lithium chloride as the additive), followed by ultrasound-assisted extraction. To obtain higher extraction yields, the effects of the relevant experimental parameters (including heat treatment temperature and time, relative amounts of 1-butyl-3-methylimidazolium bromide and lithium chloride, power and time of the ultrasound irradiation, and the liquid–solid ratio) are evaluated and response surface methodology is used to optimize the significant factors. The morphologies of the treated and untreated P. edulis leaves are studied by scanning electron microscopy. The improved extraction method proposed provides high extraction yield, good repeatability and precision, and has wide potential applications in the analysis of plant samples.
研究领域:
植物化学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Xiang Pu,Jiahua Zhang,Jinwei He,Zhihui Ai,Xiaoxue He,Xiaojun Zhou,Shiyuan Tong,Xinyue Dai,Qiqi Wu,Jiayu Hu,Jingshu He,Hanguang Wang,Wei Wang,Jinqiu Liao,Li Zhang
The biosynthetic route for flavonol in Camptotheca acuminata has been recently elucidated from a chemical point of view. However, the genes involved in flavonol methylation remain unclear. It is a critical step for fully uncovering the flavonol metabolism in this ancient plant. In this study, the multi-omics resource of this plant was utilized to perform flavonol O -methyltransferase-oriented mining and screening. Two genes, CaFOMT1 and CaFOMT2 are identified, and their recombinant CaFOMT proteins are purified to homogeneity. CaFOMT1 exhibits strict substrate and catalytic position specificity for quercetin, and selectively methylates only the 4′-OH group. CaFOMT2 possesses sequential O -methyltransferase activity for the 4′-OH and 7-OH of quercetin. These CaFOMT genes are enriched in the leaf and root tissues. The catalytic dyad and critical substrate-binding sites of the CaFOMTs are determined by molecular docking and further verified through site-mutation experiments. PHE181 and MET185 are designated as the critical sites for flavonol substrate selectivity. Genomic environment analysis indicates that CaFOMT s evolved independently and that their ancestral genes are different from that of the known Ca10OMT . This study provides molecular insights into the substrate-binding pockets of two new CaFOMTs responsible for flavonol metabolism in C. acuminata .
研究领域:
植物生物化学
·
分子生物学
·
植物化学
✓ 已验证
DOI
PubMed
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2021
·Vol. 222
·期 23
·2100284
·
IF 2.527
Da Zhang,Jinxin Zheng,Pengfei Zhang,Ronghui Zhao,Zhuo Chen,Meng Wang,Kuilin Deng
In the synthesis of traditional AIE-active polymers with conjugate or multi-benzene system, the troublesome process is still faced such as consuming time, high temperature, catalysis, no water or vacuum, and so on. In this study, the polydihydropyrimidone derivatives (PDPMDs) with AIE properties are facilely synthesized by the introduction of 4-dihydropyrimidone rings onto non-AIE-active intermediate polyureas (PUs) in Biginelli reaction. It is found that the unsymmetrical L- lysine ethyl diisocyanate and butylenediamine played a very important role in the smooth preparation and fluorescence enhancement of PDPMDs. Compared with the intermediate PUs, the fluorescence of PDPMDs is significantly enhanced (35-fold increase), which is mainly due to the intramolecular aggregation of dihydropyrimidone rings on PUs chains. At the same time, with the increase of the content of dihydropyrimidone rings, the fluorescence intensity of PDPMDs also increases, and the emission wavelength shows an obvious red shift. The fluorescence of PDPMDs also showed obvious dependence on excitation wavelength, which further reveals the clusterization-triggering emission (CTE) mechanism. In summary, the strategy of endowing AIE properties to non-AIE active polymer by introducing heterocycles into the backbone through multi-component reaction provides useful guidance for AIE functionalization of other non-AIE materials.
研究领域:
材料科学
·
化学
·
高分子科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Xingjie Yang,Xubao Jiang,Muhammad Sohail Bashir,Xiang Zheng Kong
Polyurethanes (PUNs) have been widely used in many fields. However, there are few reports on their microsphere preparation through precipitation polymerization. Herein, uniform PUN microspheres are prepared by precipitation polymerization of toluene diisocyanate and trimethylolpropane, without any surfactant and stabilizer. Under optimized conditions, monomers are fully polymerized within 2 h at a monomer concentration as high as 25.0 wt %, with a high yield of the microspheres (96.9%). By loading Pd on their surface, composite microspheres Pd@PUN are obtained and used as catalysts. 4-Nitrophenol is completely reduced within 1 min, with a kinetic constant of 4.96 min–1, significantly higher than many reported Pd-loaded catalysts, and with comparable reusability. Used in degradation of dye molecules, the catalytic performance is practically unchanged after 20 recycled uses. This work provides a simple method for the preparation of highly uniform PUN microspheres with a high yield and their Pd-loaded catalysts, both of great potential for various applications.
研究领域:
材料科学
·
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL PHYSICS
·
2020
·
IF 1.771
Lizhi Zhao,Yaxiang Zhao,Rishun Li,Dihao Wu,Xingyu Xie,Hui Ye,Yuzhong Zhang,Qingping Xin
Metal-organic frameworks (MOFs) of copper-tetrakis-(4-carboxyphenyl)-porphyrin (CuTCPP) were prepared by a solvothermal route. The two-dimensional (2D) ultrathin nanosheets with larger specific surface area show higher adsorption capacity for rhodamine B (RhB), compared with the bulk MOF of CuTCPP. The binding mechanism of the 2D nanosheets with RhB was investigated based on spectroscopic methods . The results reveal that the fluorescence of RhB is efficiently quenched by 2D CuTCPP nanosheets , and the quenching mechanism is totally the static quenching by forming a ground state RhB-CuTCPP nanosheets complex with an apparent association constant of 3.953 × 10 3 M −1 . The interaction between RhB and CuTCPP nanosheets leads to the H-aggregate of RhB in the complex. Higher-order aggregate may also be involved in the complexation. Thermodynamic studies demonstrate that RhB-CuTCPP nanosheets interaction is a spontaneous process and driven by electrostatic and hydrophobic forces . The 2D CuTCPP nanosheets can be regenerated from the complex and used repeatedly.
研究领域:
材料科学
·
光谱学
·
环境科学
✓ 已验证
DOI
高影响因子
E-POLYMERS
·
2022
·Vol. 22
·期 1
·488-504
·
IF 3.074
Fangsheng Wu,Zihua Zhang,Wei Liu,Yuan Liu,Xiujuan Chen,Pingyong Liao,Qiaoying Han,Lun Song,Hong Chen,Wenbin Liu
In this study, a novel material of core–shell structured magnetic molecularly imprinted polymers (Fe 3 O 4 @SiO 2 @Au (FSA)-MIPs) was successfully prepared for the rapid and selective determination of 4-methylmethcathinone (mephedrone, 4-MMC). The adsorption capacity of FSA-MIPs is 34.7 mg·g −1 at 308 K, which is significantly higher than magnetic non-imprinted polymers profiting from the imprinting effect. The FSA-MIPs have a short equilibrium (20 min) and could be reused more than six times. Moreover, the selectivity coefficients of FSA-MIPs for 4-MMC, 3,4-dimethylmethcathinone, butylone, 4-ethylmethcathinone, acetylfentanyl, and methylene blue are 4.01, 5.65, 7.62, 12.30, and 20.87 respectively, further indicating the markedly enhanced binding selectivity of FSA-MIPs. As an adsorbent, the FSA-MIPs were successfully applied for effective extraction of 4-MMC in three human urine samples with the recovery rates ranging from 85.5–92.6%. The results confirmed that the FSA-MIPs have good prospects in the extraction and separation of synthetic cathinones, which is suitable for further application in the criminal sciences field.
研究领域:
分析化学
·
法医学
✓ 已验证
DOI
高影响因子
CELLULAR AND MOLECULAR LIFE SCIENCES
·
2026
·Vol. 83
·期 1
·219
·
IF 6.5
Fan Xinxin,Yan Jinhua,Yuan Yu,Chen Yi,Chen Haiyang
The global incidence of inflammatory bowel disease (IBD) is rising, an epidemiological trend strongly linked to the increasing consumption of ultra-processed foods. Although certain food additives are implicated in IBD pathogenesis, the direct impact of these additives on intestinal stem cells (ISCs), key effectors of epithelial homeostasis and repair, is poorly defined. Specifically, 4-hexylresorcinol (4-HR), a widely used phenolic preservative, has not been thoroughly investigated for its long-term impact on intestinal health, particularly during inflammation and repair. Using a Drosophila melanogaster model of bleomycin (BLM)-induced intestinal injury, we combined genetic analysis, immunofluorescence staining, and functional assays to evaluate the effects of 4-HR on tissue pathology, ISC proliferation, and evolutionarily conserved pro-repair signaling pathways. Our findings indicate that 4-HR significantly aggravates intestinal damage and impedes epithelial regeneration by suppressing the injury-induced proliferation of ISCs. Mechanistic studies revealed that 4-HR inhibits the activation of the MAPK signaling pathway, which is critical for initiating the reparative program following injury. Importantly, we extend these findings to a mammalian system, demonstrating that 4-HR similarly impairs intestinal repair and suppresses the conserved MAPK signaling axis in a mouse model of colitis. Collectively, our data elucidate a previously unrecognized mechanism whereby the food additive 4-HR aggravates intestinal damage and impedes epithelial regeneration by directly suppression MAPK-dependent, ISC-driven repair. This cross-species validation establishes the detrimental role of 4-HR and its core mechanism as conserved from invertebrates to mammals, not only establishing a novel link between dietary factors and epithelial repair dysregulation but also underscoring a significant dietary environmental contributor to IBD pathogenesis. Furthermore, this study establishes a foundation for future research into how dietary components influence stem-cell biology, underscoring the urgent need to re-evaluate the long-term safety of common food additives in vulnerable populations.
✓ 已验证
DOI
高影响因子
CHEMICAL PAPERS
·
2023
·Vol. 77
·期 11
·6637-6646
·
IF 2.2
Chen Lei,Li Rongxin,Li Yuanlong,Shu Qijiang,Yang Tao
The reduced graphene oxide aerogel modified by 4-chlorophenyl sulfoxide was obtained by a simple self-assemble process under the basic reduction-oxide condition, then freeze-dried for future using. The prepared aerogel was shortly named 4CS-rGO, which was characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, et al. 1 mg of 4CS-rGO composite was used as an adsorbent to adsorb Pd(II) and Pt(IV) in 1.0 mL 40 mM Britton-Robinson buffer solution with various pH. The adsorption efficiency of Pd(II) increased with the increase in pH, whereas the hydrolysis of Pd(II) happened at pH 13, and the maximum adsorption efficiency of Pd(II) was 91.82% at pH 12, which was mainly driven by electrostatic attraction. Besides, the adsorption behavior of the 4CS-rGO composite for Pt(IV) was explored to evaluate the possibility to isolate Pd(II) and Pt(IV) ions by using aerogel. We found that, quite interestingly, hydrogen bond, hydrophobic interaction and van der Waals force can strongly conquer electrostatic repulsion driven Pt(IV) ions adsorption behavior at pH 5, and Pt(IV) ions displaced by cationic surfactant. Moreover, a tighter Pt(IV) ions adsorption behavior than Pd(II) ions was observed while we adsorb them respectively with/without 4-chlorophenyl sulfoxide modified the graphene, while branched TBAB was easier and more effectively replaced the adsorbed Pt(IV) ions than strained CTAB.
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产品关联
DOI
高影响因子
ANALYTICAL BIOCHEMISTRY
·
2018
·
IF 2.275
Lufei Zheng,Chao Zhang,Jun Ma,Sihui Hong,Yongxin She,A.M. Abd EI-Aty,Yahui He,Hailong Yu,Haijin Liu,Jing Wang
Herein, an imprinted electrochemical sensor based on graphene-Au nanoparticles incorporated with molecularly imprinted polymer (MIP) was fabricated for determination of 4-nonylphenol (4-NP). Grafted MIP electropolymerized on nanoscale multilayer films electrode was achieved using 4-NP as a template and P-aminothiophenol as a functional monomer . The electrochemical properties of the MIP nanoscale multilayer membrances were characterized and measured by cyclic voltammetry and differential pulse voltammetry techniques; using ferrocyanide/ferricyanide-redox marker. Several important parameters were optimized and investigated to improve the performance of the sensor. Under the optimized conditions, the developed sensor showed an excellent linear response over the concentration ranges of 50–500 ng mL −1 (4-NP) with a detection limit of 0.01 ng mL −1 (S/N = 3). The developed sensor showed a good selective recognition of 4-NP compared with structural analogue, exhibited a good reproducibility and accuracy with long-term stability. At last, the feasibility of the proposed methodology was successfully applied fordetection of 4-NP in milk and its packaging materials .
研究领域:
分析化学
·
环境科学
·
食品科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）