MACROMOLECULAR CHEMISTRY AND PHYSICS
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2019
·Vol. 220
·期 9
·1900022
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IF 2.622
Wenxiu Zhang,Xianhong Zhang,Yuhong Ma,Dong Chen,Wantai Yang
With UV–vis absorption in the range of 270–435 nm, 4-( N , N -diphenylamino)benzaldehyde (DPAB) takes efficient photoreduction quench with 4-cynao-4-(phenylcarbonothioylthio)pentanoic acid (CTP). The polymerization rates of methyl methacrylate (MMA) are 0.019, 0.056, and 0.102 h −1 at 33, 40, and 50 °C, respectively, in the presence of DPAB and CTP under visible-light irradiation. Dark reaction produces no PMMA at 50 °C for 120 h. The living feature is demonstrated by linearly increasing M n with the monomer conversions and narrow polydispersity index (PDI), chain extension, and block polymerizations with benzyl methacrylate (BnMA) and poly(ethylene glycol) monomethyl ether methacrylate (PEGMA). With PMMA-CTP ( M n = 6800, PDI = 1.17), chain extension gives PMMA with M n = 15 900 and PDI = 1.15. With PMMA-CTP ( M n = 6000, PDI = 1.21) as macro-RAFT, PMMA- b -PBnMA of M n = 12 600 (PDI = 1.44) and M n = 18 500 (PDI = 1.31) are prepared. These results support that there is a positive synergistic effect between polymerization temperature and visible-light irradiation on the photo-RAFT without losing the living features.
研究领域:
高分子化学
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材料科学
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2020
·
IF 3.862
Faliang Luo,Juntao Ren,Chunyu Li,Yanming Hu,Guangyuan Zhou
A styrene derivative, 4-N,N-dimethylaminostyrene (MAS), serving as both catalyst and monomer was exploited in reversible complexation mediated polymerization (RCMP). Radical trap experiment and UV–vis spectroscopy analysis revealed that MAS as a catalyst could abstract iodine from iodine-containing compound to generate propagating radical species. Kinetic studies demonstrated that the polymerization of styrene in the presence of MAS proceeded in a “living”/controlled manner, affording polymers with controlled molecular weights and narrow molecular weight distributions. The livingness of the obtained polymer was confirmed by chain extension. Determined by water contact angle measurement, incorporation of MAS into the polymer led to the enhancement of surface energy. Moreover, using α,ω-bis(2-iodo-2-phenylacetoxy)-end functionalized cis -1,4-polyisoprene as a macroinitiator which was synthesized through cross-metathesis of cis -1,4-polyisoprene with cis -1, 4-bis(2-iodo-2-phenylacetoxy)-2-butene, the polymerization of styrene in the presence of MAS also exhibited typical features of “living”/controlled radical polymerization to yield polystyrene-block-polyisoprene-block-polystyrene.
研究领域:
高分子科学
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材料科学
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化学工程
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DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2017
·
IF 3.034
Li Luo,Yuan Yang,Qiang Wang,Hai-pu Li,Zhou-fei Luo,Zhi-peng Qu,Zhao-guang Yang
The presence of endocrine disrupting chemicals such as 4- n -octylphenol, 4- n -nonylphenol and bisphenol A in environmental samples and artificial products may cause health problems for human and organisms. This developed method was efficient for monitoring of those tracing emerging contaminates and the Plackett-Burman factorial design introduced in extraction step was timesaving. Matrix effect was also considered to ensure proper quantitation. Good linearity (r 2 > 0.99), low Method Detection Limits (MDL) and Method Quantitation Limits (MQL) range from 0.18 to 0.54 ng/g and 0.60 to 1.80 ng/g were obtained. Three level spiking experiment (4, 10, 15 ng/g) showed recoveries range from 74% to 113% for 4- n -octylphenol and 4- n -nonylphenol with RSD range from 2% to 11%. The method was finally applied to the analysis of real fish samples taken from Hunan Province, China, offering a reliable and effective means for monitoring of trace emerging contaminates in fishes largely consumed by residents.
研究领域:
环境科学
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分析化学
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毒理学
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DOI
高影响因子
TALANTA
·
2024
·
IF 5.6
Qing Liu,Si Chen,Yiming Nie,Qian Li,Fang Chen
4- n -butylresorcinol (4nBR) is a frequently utilized as whitening ingredients in skincare cosmetics. Compared with other whitening ingredients, it can effectively inhibit tyrosinase with lower toxicity and superior inhibition efficacy. Under alkaline conditions, an induced oxidative coupling reaction can occur between 4nBR and dopamine (DA) to generate strong fluorescent substance azamonardine with an intense emission band centering at 476 nm when excited at 440 nm. This phenomenon can be used to establish a fluorescence analysis method for 4nBR. The results indicated that the linear range of the method was 1.0–24.0 nmol L −1 , and the detection limit was as low as 0.25 nmol L −1 . The method showed high sensitivity, good selectivity, mild experimental conditions and low cost. The proposed method was successfully used to detect 4nBR in cosmetics, and the results were consistent with those of HPLC. The spiking recoveries were between 98.2% and 108 %.
研究领域:
分析化学
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生物学
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医学
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产品关联
DOI
PubMed
高影响因子
Current Analytical Chemistry
·
2024
·Vol. 22
·期 1
·84-91
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IF 1.7
Si Chen,Yiming Nie,Qing Liu,Fang Chen
Background4-n-butylresorcinol (4nBR) was widely used in the treatment of chloasma and skin whitening cosmetics. As a decolorizing agent, it can effectively control the activity of tyrosinase. Market regulatory authorities require truthful labeling of ingredients in cosmetics. Therefore, the quantitative determination of 4nBR is of great practical significance.HypothesisAt present, the main detection method of 4nBR reported in the literature is HPLC. Compared with the HPLC method, optical methods offer several advantages, including low cost, and simplicity, which make them suitable for on-field detection applications. A convenient spectrophotometric method was established for 4nBR detection.MethodsFe3+ can oxidize the common colorless chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxTMB. Based on the fact that 4-n-butyl resorcinol (4nBR) can reduce oxTMB, a convenient and rapid spectrophotometric method for the determination of 4nBR was proposed.ResultsUnder the optimum conditions, the absorbance at 652 nm has a good linear relationship with the concentration of 4nBR in the range of 1.2 - 16 μM. The linear equation for the detection of 4nBR was ΔA = 0.0546 c (μM) - 0.0026 (r2=0.9962), and the detection limit was 0.33 μM. The accuracy of this method is comparable to that of HPLC.ConclusionThis method has good selectivity for 4nBR and good anti-interference ability for common additives in cosmetics. The proposed method can be applied to the determination of 4nBR in thereal samples.
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高影响因子
ELECTROCHIMICA ACTA
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2024
·
IF 5.5
Zhefei Zhao,Xuyao Yao,Linlin Zhang,Minhao Chen,Xingyu Luo,Ruopeng Yu,Yinghua Xu,Youqun Chu,Xinbiao Mao,Huajun Zheng
Electrochemical selective dechlorination for the synthesis of high value-added chemical products is an economical and promising technology. Although silver (Ag) electrode is the most representative catalyst in most electrocatalytic dehalogenation reactions, the selectivity for specific reaction needs to be improved. In this framework, AgCu bimetallic electrocatalysts were designed for the selective dechlorination of 4-amino-3,5,6-trichloropyridine carboxylic acid (4-N-3,5,6-TCP) to 4-amino-3,6-dichloropyridolinic acid (4-N-3,6-DCP). The optimum Ag 16 Cu 4 electrode exhibits excellent performance with 99.0% selectivity and 98.8% yield of 4-N-3,6-DCP, surpassing the pure Ag electrode. The combined results of experimental measurements and theoretical calculations indicated that the introduction of Cu modulates the electronic structure of Ag, which not only promoted the transfer of charges, but also reduces the energy barrier of the rate-determining step (the C H formation). In addition, the practicality and scalability of this system was evaluated using a flow-cell reactor. This study demonstrates that AgCu bimetallic catalyst plays a crucial role in determining the selectivity and activity in the electrochemical dechlorination of 4-N-3,5,6-TCP and displays the prospective applications.
研究领域:
环境科学
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材料科学
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电化学工程
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2018
·Vol. 30
·期 2
·1699-1705
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IF 2.324
Teng Fei,Chen Dong,Ma Yuzhe,Ji Shaohua,Liu Jiaojiao,Wang Tianhua,Tang Jie,Cao Lifeng,Teng Bing
N,N -dimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS)-graphene ex-situ and in-situ composite films with 2% concentration of graphene were first prepared and systematically investigated. The crystallinity of DSTMS-based composite films were confirmed by XRD analysis, and the functional groups of composite films can be obtained by FT-IR. Optical absorptions were recorded using UV–Vis-NIR spectral analysis, and the band gap and extinction coefficient of the films were calculated. The thermal stability of the composite films were analyzed by TG/DSC. The pressure sensitive resistance test showed that the pressure sensitive signal of the composite films were significantly increased after graphene added, while the signal of DSTMS film eventually disappears. This work expands the application of organic nonlinear crystal DSTMS in optics and electricity by doping graphene.
研究领域:
材料科学
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凝聚态物理
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功能材料
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非线性光学
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纳米复合材料
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电学性能
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光学性能
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热分析
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DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2024
·
IF 4
Tianyang Hou,Yuangang Xu,Ze Xu,Xiaopeng Zhang,Ming Lu
The formation of non-metallic pentazolate salts from the combination of simple nitrogen-rich cations with cyclo -N 5 − is expected to be applied in propellants and explosives. In this work, a series of structurally similar cations ([NH 3 CH 3 ] + , [NH 2 (CH 3 ) 2 ] + , [NH(CH 3 ) 3 ] + , and [N(CH 3 ) 4 ] + ) were used to synthesize four cyclo -N 5 − containing energetic salts, and the contribution of crystal stacking mode, hydrogen bonding, C–H··· π and π -stacking interactions in the stabilization of cyclo -N 5 − salts has been investigated by geometrical and Hirshfeld surface analyses as well as theoretical calculations. All salts have been thoroughly characterized by single-crystal X-ray diffraction, infrared (IR), multinuclear NMR ( 1 H and 13 C) spectroscopy, and elemental analysis. The decomposition temperatures of all salts are higher than 75 °C, as measured by thermogravimetric (TG). These compounds all show low sensitivities (IS ≥ 35 J, FS > 360 N) measured by standard BAM methods. Their heats of formation and detonation performances were calculated using the Born–Haber energy cycle and K-J method (“Pilem” program), respectively. This study has great significance for future design and synthesis of cyclo -N 5 − containing energetic materials.
研究领域:
化学
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材料科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF COSMETIC SCIENCE
·
2024
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IF 2.7
Yuwen Wu,Ling Ma,Timson Chen,Kuan Chang,Jing Wang
en Objectives Conventional hair permanent waving (PW) and permanent straightening processes typically involve two steps: reduction, for breaking -S-S- bond in cystine into cysteine and oxidation for -S-S- bond reconnection. However, it is known that the hair incurs damage during the oxidation step. In this work, we proposed a novel strategy to reconnect reduced disulfide bonds in hair via the thiol-Michael click reaction, by using a symmetric Michael reagent. Methods Virgin black Chinese hair was reduced using 8% wt thioglycolic acid and employed as model hair containing a high content of broken disulfide bonds. The reduced hair was treated with 1,4-n-butylene dimaleate. Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to verify the chemical changes occurred in untreated and treated hair fibre. Single-fibre mechanical properties and thermal properties of the hair were evaluated using tensile testing and differential scanning calorimetry (DSC), respectively. Results The 1,4-n-butylene dimaleate could reconnect free thiol groups generated by disulfide bond reduction via thiol-Michael click reaction and significantly improve the mechanical strength of hair compared to that of the reduced hair. Secondary conformational resolution analysis of FT-IR results revealed that the content of α -helix structure could be restored after treatment with 1,4-n-butylene dimaleate. The intermolecular forces established by the newly generated C-S bonds compensate the broken disulfide bonds and enhance the fracture strength of the hair compared to that of reduced hair. Michael reagents of similar structure also showed similar performance in restoring the mechanical properties of reduced hair. Conclusions Our data suggest that 1,4-n-butylene dimaleate can restore the mechanical properties of reduced hair by reconnecting reduced disulfide bonds and restoring the secondary conformation of hair keratin. Résumé fr Objectifs Les processus classiques d’ondulation permanente (OP) et de lissage permanent des cheveux impliquent généralement deux étapes : la réduction, pour rompre la liaison -S-S- de la cystine en cystéine, et l’oxydation, pour reconnecter la liaison -S-S-. Cependant, on sait que les cheveux subissent des dommages pendant l’étape d’oxydation. Dans ce travail, nous avons proposé une nouvelle stratégie pour reconnecter les liaisons disulfures réduites dans les cheveux via la réaction de thiol-Michael, en utilisant un réactif de Michael symétrique. Méthodes Des cheveux noirs vierges chinois ont été réduits à l’aide d’acide thioglycolique à 8 % en poids et utilisés comme modèle de cheveux contenant une grande quantité de liaisons disulfures cassées. Les cheveux réduits ont été traités avec du dimaléate de 1,4-n-butylène. La spectroscopie de Raman et la spectroscopie infrarouge à transformée de Fourier (FT-IR) ont été utilisées pour vérifier les changements chimiques survenus dans les fibres capillaires non traitées et traitées. Les propriétés mécaniques à fibre unique et les propriétés thermiques des cheveux ont été évaluées à l’aide d’un test de traction et d’une calorimétrie différentielle à balayage (Differential Scan Calorimetry, DSC), respectivement. Résultats Le dimaléate de 1,4-n-butylène pourrait reconnecter les groupes thiol libre générés par la réduction des liaisons disulfures via la réaction de thiol-Michael et améliorer de manière significative la résistance mécanique des cheveux par rapport à celle des cheveux réduits. L’analyse de la résolution conformationnelle secondaire des résultats de la FT-IR a révélé que le contenu de la structure en hélice alpha pouvait être restauré après un traitement avec le dimaléate de 1,4-n-butylène. Les forces intermoléculaires établies par les nouvelles liaisons C-S compensent les liaisons disulfures cassées et améliorent la résistance à la rupture des cheveux par rapport à celle des cheveux réduits. Les réactifs de Michael de structure similaire ont également montré des performances similaires dans la restauration des propriétés mécaniques des cheveux réduits. Conclusions Nos données montrent que le dimaléate de 1,4-n-butylène peut restaurer les propriétés mécaniques des cheveux réduits en reconnectant les liaisons disulfures réduites et en restaurant la conformation secondaire de la kératine des cheveux.
研究领域:
生物化学
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材料科学
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化妆品科学
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DOI
PubMed
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2018
·
IF 3.974
Lu Wang,Yuan Kang,Siyun Liang,Danying Chen,Qiuyun Zhang,Lixuan Zeng,Jiwen Luo,Feng Jiang
Toxicological effect of freshwater algae co-exposure to Cd and 4-n-nonylphenol (4-n-NP) was seldom reported. In the present study, Chlorella sorokiniana was selected for testing the single and combined effect of Cd and 4-n-NP by detecting the growth inhibition and oxidative stress after exposure for 48 h, 72 h, and 96 h. The combined effects were evaluated by using toxic units (TU) method and concentration addition（CA）model. The synergistic effect of mixture on algal growth inhibition was both observed at 48 h and 72 h, and the additive effect was observed at 96 h. In addition, the significant alterations of superoxide, thiobarbituric acid reactive substances and antioxidant defenses (superoxide dismutase, catalase , glutathione) have been detected. It could be observed that the mixture predominantly lead to synergistic effects in superoxide induction, and the antagonistic effects in the GSH induction. A similar trend between the superoxide induction and growth inhibition were observed, which may indicate that the oxidative effects of Chlorella sorokiniana contributed to the growth inhibition after exposure to Cd and 4-n-NP. These findings may have important implications in the risk assessments of heavy metals and endocrine disruptors in the aquatic environment.
研究领域:
环境毒理学
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水生生物学
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生态毒理学
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DOI
PubMed
高影响因子
ENVIRONMENTAL GEOCHEMISTRY AND HEALTH
·
2020
·Vol. 42
·期 9
·2881-2894
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IF 3.472
Ding Na,Wang Lu,Kang Yuan,Luo Kesong,Zeng Diya,Man Yu Bon,Zhang Qiuyun,Zeng Lixuan,Luo Jiwen,Jiang Feng
The transcriptomic response of green microalga Chlorella sorokiniana exposure to environmentally relevant concentration of cadmium(II) (Cd) and 4- n -nonylphenol (4- n -NP) was compared in the present study. Cd and 4- n -NP exposure showed a similar pattern of dys-regulated pathways. The photosystem was affected due to suppression of chlorophyll biosynthesis via down-regulation of Mg-protoporphyrin IX chelatase subunit ChlD (CHLD) and divinyl chlorophyllide a 8-vinyl-reductase (DVR) in Cd group and via down-regulation of DVR in 4- n -NP group. Furthermore, the reactive oxygen species (ROS) could be induced through down-regulation of solanesyl diphosphate synthase 1 (SPS1) and homogentisate phytyltransferase (HPT) in Cd group and via down-regulation of HPT in 4- n -NP group. Additionally, Cd and 4- n -NP would both cause the dys-regulation of carbohydrate metabolism and protein synthesis. On the other hand, there are some different responses or detoxification mechanism of C. sorokiniana to 4- n -NP stress compared to Cd exposure. The increased ROS would cause the DNA damage and protein destruction in Cd exposure group. Simultaneously, the RNA transcription was dys-regulated and a series of changes in gene expressions were observed. This included lipid metabolism, protein modification, and DNA repair, which involved in response of C. sorokiniana to Cd stress or detoxification of Cd. For 4- n -NP exposure, no effect on lipid metabolism and DNA repair was observed. The nucleotide metabolism including pyrimidine metabolism and purine metabolism was significantly up-regulated in the 4- n -NP exposure group, but not in the Cd exposure group. In addition, 4- n -NP would induce the ubiquitin-mediated proteolysis and proteasomal degradation to diminish the misfolded protein caused by ROS and down-regulation of heat shocking protein 40. In sum, the Cd and 4- n -NP could cause the same toxicological effects via the common pathways and possess similar detoxification mechanism. They also showed different responses in nucleotide metabolism, lipid metabolism, and DNA repair.
研究领域:
环境毒理学
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分子生物学
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微藻研究
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产品关联
DOI
PubMed
高影响因子
Microbial Cell Factories
·
2025
·Vol. 24
·期 1
·1-12
·
IF 4.9
Tian Yongqing,Yang Yige,Ni Minmin,Wo Jing
Background Vanillin is a widely utilized flavor compound of significant value in the food and pharmaceutical sectors, which can be obtained through natural extraction, chemical synthesis, or biotechnological processes. However, the yield from vanilla pods is insufficient to meet market demand, and chemically synthesized vanillin not only encounters limitations in its application within the food and pharmaceutical industries but also needs to address environmental concerns and unsustainable raw material sources. Hence, it is imperative to explore alternative approaches to develop an efficient and cost-effective green vanillin. To address the challenges encountered in vanillin biosynthesis, such as substrate uptake limitations and product-induced inhibition of cell growth,we leveraged the advantages of surface display technology and artificial multi-enzyme scaffolds to construct a hybrid surface-display biocatalytic system by assembling Eugenol oxidase (EUGO) and dioxygenase (NOV1), which can convert lignin biowaste 4- n -propylguaiacol (4-PG) into vanillin on the surface of Escherichia coli BL21(DE3). Results To assemble bioactive macromolecules of EUGO and NOV1 on the surface of E. coli BL21(DE3), we utilized Lpp-OmpA-SpyCatcher (LOAS) as an anchoring motif and displayed EUGO-linker-NOV1-SpyTag (ELNS) by covalent interaction between SpyTag andSpyCatcher to allow their spatial proximity. After optimization of the reaction system, our self-assembly display system exhibited highly efficiency in converting 4-PG into vanillin and reached a final concentration of vanillin at 12.58 g/L, 2.5 times higher than that achieved by thewhole-cell biocatalytic system. The LOAS-ELNS display system was applied to the sustainable biosynthesis of vanillin from lignin-derived 4-n-propylguaiacol at least 10 times. Conclusions This work provided a generalized approach to co-expressing proteins and offered an efficient, eco-friendly, and renewable method for the biosynthesis of vanillin from 4-PG.
研究领域:
生物化学
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合成生物学
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环境科学
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DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）