REACTIVE & FUNCTIONAL POLYMERS
·
2020
·
IF 3.333
Yu Tang,Qinya Wang,Lexuan Wu,Kuan Liu,Wenjing Wang,Yinghua Shen,Yuyuan Xue,Sheng Dai
pH-Responsive copolymers with reversible transformation ability have been investigated as new effective carriers for L-proline to catalyze asymmetric aldol reaction in water. A series of block copolymers of mPEG- b -P(DEA x - co -L-ProlA y ) (mPEG-PDL) bearing L-proline catalytic sites and pH-responsive poly (diethylaminoethyl methacrylate) (PDEA) segments were synthesized by the reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of methyl polyethylene glycol (mPEG) trithiocarbonate macro-RAFT agent. The pH-induced self-assembly behaviors of three copolymer catalysts with different contents of PDEA were investigated via the combination of UV–visible spectrometer (UV–vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM). Catalytic activity and stereoselectivity of these copolymer catalysts were evaluated by direct asymmetric aldol reaction of p -nitrobenzaldehyde and cyclohexanone in water. The results indicated that catalytic activity and stereoselectivity effected by the pH value of aqueous solution and the structures of copolymer catalyst assemblies. mPEG-PDL-2 give the aldol product with high conv., yield, anti/syn , and ee (92%, 91%, 92/8 , 96%), respectively at pH 7.0. Furthermore, these pH-responsive copolymers supported L-proline are easily recycled by a reversible phase transition.
研究领域:
有机化学
·
高分子化学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL CHEMISTRY
·
2018
·Vol. 73
·期 8
·817-823
·
IF 0.971
Hu Q. Q.,Gao H.,Wang Y. M.,Ma W.,Sun D. M.
Abstract The poly(L-arginine)–graphene modified glassy carbon electrode ( GCE ) was fabricated and the electrochemical behavior of carmine and amaranth on this electrode was studied by cyclic voltammetric method. Compared with poly(L-arginine)/GCE and GCE, the poly(L-arginine)–graphene modified GCE improved the sensitivity for the determination of carmine and amaranth. The experimental results indicated that the oxidation peaks of carmine and amaranth were separated at 121 mV in phosphate buffer solution at pH 2.5. The linear range for the simultaneous determination of carmine and amaranth were 7.5 × 10 –7 –7.5 × 10 –5 M. The detection limits were 7 × 10 –8 M for carmine and 2.5 × 10 –7 M for amaranth. The method has been applied to the simultaneous determination of carmine and amaranth in drinks with satisfactory results.
研究领域:
分析化学
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食品科学
·
电化学
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Renjie Ji,Defu Yin,Yao Chen,Like Ma,Fanglin Lv,Yuhao Zhang,Zhen Jia,Jingyun Zhang,Mingya Liu,Shitao Yu,Yue Liu
A core–shell catalyst mZSM-5@SO 4 2- /mSiO 2 composed of mZSM-5 core and SO 4 2- /mSiO 2 shell was prepared by the soft template method. Core-shell structure could promote the building of Brønsted -Lewis (B-L) acids interface and significantly improve the synergistic effect of B-L. In this paper, the Brønsted/Lewis (B/L) of mZSM-5@SO 4 2- /mSiO 2 was targeted regulating by innovatively introducing Brønsted acid (BA) sites into the shell. The optimal mZSM-5@SO 4 2- /mSiO 2 catalyst (B/L = 0.142) could achieve 72.1 % furfural yield at 140 ℃ for 1 h. In addition, 70.2 % furfural yield could be obtained after the catalyst was recycled and regenerated for 5 times. Combining In-situ IR and 13 C NMR, the reaction path was revealed in detail: xylose was first isomerized to xylulose and then dehydrated to furfural. This paper provides a research idea for the directional regulation of dual active sites of cascade reaction catalysts.
研究领域:
催化化学
·
生物质转化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2015
·Vol. 38
·期 18
·3279-3287
·
IF 2.737
Ji Li,Xiaoling Hu,Ping Guan,Dongmen Song,Liwei Qian,Chunbao Du,Renyuan Song,Chaoli Wang
In this study, dummy imprinting technology was employed for the preparation of l- phenylalanine-imprinted microspheres. Ionic liquids were utilized as both a “dummy” template and functional monomer, and 4-vinylpyridine and ethylene glycol dimethacrylate were used as the assistant monomer and cross-linker, respectively, for preparing a surface-imprinted polymer on poly(divinylbenzene) microspheres. By the results obtained by theoretical investigation, the interaction between the template and monomer complex was improved as compared with that between the template and the traditional l- phenylalanine-imprinted polymer. The batch experiments indicated that the imprinting factor reached 2.5. Scatchard analysis demonstrated that the obtained “dummy” molecularly imprinted microspheres exhibited an affinity of 77.4 M·10 −4 , significantly higher that of a traditional polymer directly prepared by l- phenylalanine, which is in agreement with theoretical results. Competitive adsorption experiments also showed that the molecularly imprinted polymer with the dummy template effectively isolated l- phenylalanine from l- histidine and l- tryptophan with separation factors of 5.68 and 2.68, respectively. All these results demonstrated that the polymerizable ionic liquid as the dummy template could enhance the affinity and selectivity of molecularly imprinted polymer, thereby promoting the development of imprinting technology for biomolecules.
研究领域:
化学
·
生物化学
✓ 已验证
DOI
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2025
·
IF 6.6
Lingxia Su,Mengting Qiu,Qing jiang,Huiling Li,Wenjun Liu,Xumei Wang,Jun Liu,Zongcai Tu,Yanhong Shao
The aim was to evaluate the protective effects of 0.4% L-lysine (Lys) on the gel strength, water holding capacity and protein structure of frozen silver carp surimi, and to explore the mechanism of Lys delaying the quality deterioration of frozen silver carp surimi. Compared with control groups and commercial antifreeze agents, Lys-treated frozen surimi demonstrated superior rheological properties, gel strength, water holding capacity, and whiteness after 30 d of frozen storage while exhibiting a compact gel network. The mechanism of action was mainly due to the rise of pH value in the freezing process to form myofibrillar protein aggregates that exhibited high resistance to degradation, which prevented the exposure of hydrophobic amino acids and the oxidation of sulfhydryl groups, thus affecting the effective cross-linking of proteins during the gelation process and forming a denser fiber structure. The findings demonstrated the potential of Lys as a cryoprotectant, thereby establishing a theoretical foundation for the development of eco-friendly alternatives to antifreeze and high-gel frozen surimi products.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 14
·e202500180
·
IF 2
Zhen-zhen Chen,Si-meng Liu,Ran Yang,Ling-bo Qu,Hua-jin Zeng
Graphical Hydrothermally-synthesized GCL-derived carbon dots (2.8nm) exhibited potent antioxidant activity, scavenging DPPH/ABTS radicals and protecting H9c2 cells from H₂O₂ damage. In ISO-induced AMII rats, GCL-CDs reduced ECG S-T elevation, infarct size, and cardiomyocyte apoptosis while promoting tissue repair, likely via oxidative stress alleviation, demonstrating myocardial protection. In this paper, a type of carbon dots (CDs) was prepared at 220°C for 8 h by a hydrothermal method using Geranium carolinianum L. (GCL) as the carbon source. GCL CDs were spherical in shape with the particle size of 2.8 ± 0.6 nm. In vitro studies showed that GCL CDs had a good scavenging activity against the free radicals of DPPH and ABTS, and had a good protective effect against H 2 O 2 -induced oxidative damage of H9c2 cells, suggesting that GCL CDs have good antioxidant activity. In vivo studies showed that GCL CDs had a good protective effect on isoprenaline (ISO)-induced acute myocardial ischemic injury (AMII) in rats, which was reflected by their ability to significantly reduce the S-T band of the electrocardiogram, markedly reduce the infarcted area of AMII, effectively and rapidly restore the damaged cardiomyocytes, and significantly reduce the apoptosis of the cardiomyocytes, which prevented further damage to the cardiomyocytes. The comprehensive results of the above experiments indicate that the protective mechanism of GCL CDs against AMII is probably through the elimination of oxidative stress in the body, so that the damaged cardiomyocytes can be restored, so as to play a protective effect on AMII.
研究领域:
药理学
·
纳米医学
·
心血管病学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Xue Wang,Tingjun Wang,Chengsheng Gui,Hanxiang Guo,Haili Chen
s Bamboo is a sustainable and renewable material. However, its high hydrophilicity and nutrient-rich composition make it highly susceptible to microbial colonization. In this study, a simple two-step strategy was employed to fabricate stable nano-silver particles (AgNPs) containing polymer composites on bamboo surfaces to enhance antibacterial and anti-mold properties. L-3,4-dihydroxyphenylalanine (L-DOPA) was modified onto the bamboo surface via self-polymerization, providing catechol groups capable of chelating and reducing Ag⁺ ions in situ to form AgNPs. The incorporation of polyethyleneimine (PEI) into the L-DOPA could further promote AgNPs formation and enhance stability of the composite coating. The resulting BT/L-D/PEI/Ag sample was systematically characterized by SEM, XRD, FTIR, XPS, EDS, and water contact angle measurements. The results confirmed that L-D/PEI/Ag polymer composites were successfully coated onto the bamboo surface, and the BT/L-D/PEI/Ag exhibited a significantly enhanced silver loading (6.68 wt%) compared to the BT/L-D/Ag (2.97 wt%), corresponding to a 125 % increase. The modified surface showed improved hydrophobicity with a contact angle of 94.7°, effectively inhibiting microbial adhesion. Antibacterial tests revealed that the BT/L-D/PEI/Ag achieved complete (100 %) inhibition against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ), as well as superior antifungal activity against Aspergillus niger ( A. niger ). The synergistic interaction between L-D, PEI and Ag formed an efficient antimicrobial coating, providing a promising strategy for the development of high-value, antimicrobial bamboo materials for sustainable construction and consumer products.
研究领域:
材料科学
·
表面工程
·
纳米技术
·
抗菌技术
·
可持续材料
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2024
·
IF 3.9
Limin Ren,Yuxuan Xiao,Rameswar Bhattacharjee,Jingjing Wu,Pengyi Tang,Stavros Caratzoulas,Changgong Meng,Qiang Guo,Michael Tsapatsis
Graphical Bifunctional Ti-B-Beta zeolite is demonstrated to be an efficient catalyst for sorbose production via glucose isomerization. Ethanol directs the conformation of glucose, facilitating its selective isomerization to sorbose and enables this isomerization to surpass the thermodynamic equilibrium limit by engaging in reactions with the resultant sorbose. D-Glucose-to-L-sorbose isomerization on Lewis acidic zeolite is a highly attractive avenue for sorbose production. But the L-sorbose yield is limited by the competing D-glucose-to-D-fructose isomerization and reaction equilibrium. In this work, it is suggested that ethanol directs the glucose conformation for selective D-glucose-to-L-sorbose isomerization. It also reacts with the produced L-sorbose to form ethyl-sorboside, which allows the D-glucose-to-L-sorbose isomerization to proceed beyond the thermodynamic equilibrium limit. It is shown that a bifunctional zeolite Beta containing framework titanium (Ti) and boron (B) is a selective catalyst for this tandem reaction: Lewis acidic framework Ti catalyzes the D-glucose-to-L-sorbose isomerization via an intramolecular 5,1-hydride shift process as confirmed by isotopic tracing experiments followed by 13 C-NMR, while weak Brønsted acid framework B selectively promotes the sorbose ketalization with ethanol. A remarkably high yield of L-sorbose with a high fraction of sugar (>95 %: 27 % unreacted glucose, 11.4 % fructose, 57 % sorbose) was obtained after the mixture produced in ethanol was hydrolyzed.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Li Zhang,Chao Li,Yue Chen,Shaobin Li,Xue Wang,Fengbo Li
L-tryptophan (L-Trp) is crucial for human metabolism, and its imbalance or deficiency can lead to certain diseases, such as insomnia, depression, and heart disease. Since the body cannot synthesize L-Trp and must obtain it from external sources, accurately monitoring L-Trp levels in food is essential. Herein, a nanocomposite film based on polyoxometalate (P 2 Mo 17 V), Ti 3 C 2 T x MXene , and chitosan (Cs) was developed through a green electrostatically mediated layer-by-layer self-assembly strategy for electrochemical detection of L-Trp. The composite film exhibits fast electron transfer and remarkable electrocatalytic performance for L-Trp with a wide linear range (0.1–103 μM), low limit of detection (0.08 μM, S/N = 3), good selectivity, reproducibility, and repeatability. In milk sample, the recoveries of L-Trp were from 95.78% and 104.31%. The P 2 Mo 17 V/Cs-Ti 3 C 2 T x electrochemical sensor not only provides exceptional recognition and detection capabilities for L-Trp but also shows significant potential for practical applications, particularly in food safety and quality control .
研究领域:
食品科学
·
分析化学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Wenxiao Liu,Xuehua Deng,Yutong Dong,Sunting Xuan,Zhengbiao Zhang
The synthesis of N-substituted polypeptides is challenging due to steric hindrance. Here, N-alkyl poly(l-alanine)s, with controlled molecular weights (Mns) and narrow distributions, were efficiently synthesized by primary amine-initiated and acetic acid-catalyzed ring-opening polymerizations of N-alkyl-(l)-alanine N-carboxyanhydrides [NAlkyl-(l)-Ala-NCAs] in toluene of low polarity and low proton-accepting ability. The N-alkyl poly(l-alanine)s, with chiral centers at backbones and different alkyl substituents at side chains, showed a relatively extended helical structure similar to that of the PPII-helix of poly(l-proline). The elongation of the alkyl side chains and the increase in temperatures had negligible effects on the helix structure, as revealed by the circular dichroism measurements. The differential scanning calorimetry and X-ray diffraction measurements showed that the polymers were crystalline. Besides, the NAlkyl-(l)-Ala-NCAs were capable of copolymerizing with other monomers, producing structurally diverse copolymers. The efficient synthesis of N-alkyl poly(l-alanine)s, combined with the structural tunability, hydrophobicity, crystallinity, protein-like skeleton, enzymatic stability, and stable helix, makes the polymers attractive structural units in self-assembly and the biomedical field.
研究领域:
高分子化学
·
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2024
·
IF 5.8
Xueqin Liao,Jianzhong Liu,Zexu Li,Mengxia Sun
Aluminum (Al) particles are widely used in propellants, thermite and pyrotechnics. However, commonly used micro Al has drawbacks such as agglomeration, high ignition temperature and slow burning rate, making its energy potential not fully exploited in applications. Therefore, exploring pathways to enhance the combustion of Al particles has become the focus at present. Herein, L -malic acid (LMA) was used to corrode the surface of Al particles to obtain a sample (named LMAl) with an average specific surface area of 11.456 m 2 /g (corresponding to Al particles with a diameter of 194 nm). The particle size distribution of LMAl did not change significantly compared to pristine Al. The XPS results showed that a small amount of LMA and corrosion products remained on the surface of the LMAl particles. Thermal analysis tests showed that the thermal oxidation rate and efficiency of LMAl was dramatically higher than that of pristine Al. Compared with the pristine Al, the combustion characterization parameters of LMAl such as combustion intensity, ignition delay time, maximum combustion temperature, mass burning rate and combustion efficiency were all improved. This trend was maintained after blending the ammonium perchlorate (AP). The condensed combustion products (CCPs) of Al revealed a large number of agglomerates and unburned Al particles. While many broken particles and tentacle-like structures were found in the CCPs of LMAl. Overall, compared to Al, the combustion of LMAl is significantly enhanced. The thermal reaction and combustion behaviors of the two are quite different. This study provides new insights into improving the ignition and combustion of Al.
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Zongyang Zhang,Yuping Li,Ze Chen,Fuchao Ji,Xiaohong Liang,Haicheng Xuan,Lina Han,Peide Han
Developing an economical and high-efficiency synthesis pathway of SSZ-13 zeolite is of great significance for the ammonia selective catalytic reduction of nitrogen oxides (NH 3 -SCR of NO x ) reactions. Herein, SSZ-13 zeolite were synthesized using L zeolite as the aluminum source in the presence of a mixed structure directing agent (SDA) composed of N,N,N, trimethtyl-1-adamantammonium hydroxide (TMAdaOH) and tetraethylammonium hydroxide (TEAOH). This synthesis strategy aims to accelerate the crystallization rate through interzeolite transformation, while less expensive TEAOH can play a cooperative structure-directing role, thus reducing the consumption of expensive TMAdaOH template. The results showed that pure SSZ-13 zeolites with high crystallinity can be obtained from L zeolite within 12 h at 160 ℃ under low TMAdaOH/SiO 2 ratio of 0.05 (too low to carry out the synthesis on its own in the current synthesis system) in the presence of TEAOH. Moreover, the crystallization mechanism was also investigated by XRD, FT-IR, SEM and TG-DTG techniques. It was proposed that the crystallization of SSZ-13 occurs through the formation of SSZ-13 nuclei under the direction of TMAdaOH and promotion of TEAOH, subsequently TMAdaOH was incorporated in the framework to further induce the crystal growth of SSZ-13. Especially, the zeolite crystal size can be modulated by the amount of TEAOH added. In addition, After Cu 2+ exchange, the obtained Cu-SSZ-13 sample exhibits superior catalysis performance in the NH 3 -SCR of NO x reaction, and the NO x conversion rate remained over 90 % across a broad range from 200 to 600 °C, demonstrating its significant application potentials in NO x removal from diesel vehicle exhausts.
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）