JOURNAL OF POLYMER RESEARCH
·
2019
·Vol. 26
·期 12
·1-12
·
IF 1.53
Jiao Yang,Chen Guofei,Zhou Haijun,Zhang Feng,Chen Xiaoqi,Li Yantao,Xiao Xueshan,Fang Xingzhong
A series of poly(benzimidazole-imide)s (PBIPIs) derived from different dianhydrides and 2-(3-aminophenyl)-5-aminobenzimidazole ( m -BIA) were synthesized via thermal imidization to form flexible films. This series of PBIPIs showed great T g s ranging from 296 to 484 °C, excellent thermal stability performed in 5% weight loss temperatures ( T d5% s) of 502–529 °C in N 2 and good mechanical properties (tensile strengths of 89–127 MPa, tensile moduli of 2.9–4.1 GPa and elongations at break of 3.9–6.9%). Compared with PIs derived from 6-amino-2-(4-(4-aminophenoxy)phenyl)-1H-benzimidazole ( p -BIODA), m -BIA based PBIPI films exhibited higher T g , and better solubility. Besides, the thermoplastic PBIPI resin (PI-6-PA) derived from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA) and m -BIA exhibited good melt processability with high T g of 273 °C, melt flow index (MFI) of 7.76 g/10 min, minimum complex viscosity of 11.9 × 10 3 Pa·s at 402 °C and low melt viscosity ratio of 2.46 at 400 °C.
✓ 已验证
产品关联
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2018
·Vol. 124
·期 7
·1-11
·
IF 1.604
Yao Hanyu,Shen Honglie,Tang Quntao,Yang Nannan,Zhai Zihao,Li Yufang
NaY(WO 4 ) 2 : Er 3+ phosphors with various doping concentrations of [Er 3+ ]/([Er 3+ ]+[Y 3+ ]) (0, 5, 7, 10, 12, 15%) were successfully synthesized by high-temperature solid-state reaction. X-ray diffraction (XRD) measurement demonstrated the presence of tetragonal-phase NaY(WO 4 ) 2 phosphors and Fourier transform infrared (FT-IR) spectra showed a strong υ 3 stretching vibration mode of WO 4 2− , indicating the good crystallization of the phosphors. Well-crystallized phosphors showed a fine morphology with particle sizes of 0.8–10 µm by scanning electron microscope (SEM). Under excitation of 980 nm laser, Er 3+ -doped phosphors exhibited strong green emissions centered at 527 and 549 nm in addition to a 665 nm emission band in the red region, which were assigned to the 2 H 11/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions, respectively. When the doping concentration was 10%, the intensities of green and red emissions reached their maximum values, stronger than that in 5% Er 3+ doped one by 13 times. The double-logarithm plot of the upconversion (UC) emission intensity to the excitation power for different Er 3+ doping concentrations depicted that at least two infrared photons were involved for every emitted green and red photon. UC emission intensity changing with temperature displayed different trends for the phosphors with different Er 3+ concentrations. The enhancement for green emission band centered on 549 nm could reach 50 times at 30 K in sample with 5% Er 3+ concentration. Under excitation by 355 nm laser, all the phosphors showed a strong PL emission band at 430 nm, while green luminescence band locating from 540 to 570 nm was only observed in 7, 10, and 12% Er 3+ -doped phosphors, which was ascribed to 4 S 3/2 → 4 I 15/2 transition.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2017
·Vol. 19
·期 10
·1-12
·
IF 2.02
Tian Fei,Niu Libo,Chen Bo,Gao Xuejia,Lan Xingwang,Huo Li,Bai Guoyi
A novel magnetic core-shell nanocomposite Fe 3 O 4 @Chitosan@ZnO was successfully prepared by in situ chemical precipitation method. It has a clear core-shell structure with magnetic Fe 3 O 4 (about 160 nm in diameter) as core, chitosan as the inner shell, and ZnO as the outer shell, as demonstrated by the transmission electron microscopy and the related elemental mapping. Moreover, this nanocomposite has high magnetization (43.6 emu g −1 ) so that it can be easily separated from the reaction mixture within 4 s by an external magnetic field. The introduction of the natural chitosan shell, instead of the conventional SiO 2 shell, and its combination with the active ZnO ensures this novel nanocomposite green character and good catalytic performance in the synthesis of 2-benzimidazoles with moderate to excellent isolated yields at room temperature. Notably, it can be recycled seven times without appreciable loss of its initial catalytic activity, demonstrating its good stability and making it an attractive candidate for the green synthesis of 2-benzimidazoles.
A novel magnetic core-shell nanocomposite exhibited high activity and good stability in the green synthesis of 2-benzimidazoles under mild reaction conditions.
✓ 已验证
产品关联
DOI
高影响因子
WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
·
2025
·Vol. 41
·期 11
·451
·
IF 4.2
Zhong Chenggang,Ding Weijian,Lin Haoran,Huang Jin
Cellobiose-2-epimerase is considered an ideal biocatalyst for the strictly thermodynamic synthesis of lactulose. However, its poor thermolability limits its industrial application. Herein, we successfully developed a novel thermostable cellobiose-2-epimerase for improving lactulose biosynthesis from lactose. The A242L mutant, derived from Dictyoglomus thermophilum (DiCE), was generated using semi-rational mutagenesis after computer-aided design via the FireProt web server. After systematic enzymatic characterization and optimization, A242L mutant exhibited a 123.5% T 1/2 in thermostability at 80 °C relative to the wild-type enzyme, and the E. coli BL21/pET28a(+)-A242L mutant harvested a maximal lactulose yield of 64.52%, representing a 51.38% improvement at a substrate concentration of 200 g/L for the whole-cell biotransformation reaction conducted at pH 7.0 and 80 °C for 4 h. Molecular docking and molecular dynamics (MD) simulation results indicated that the enhanced thermostability of the enzyme was closely related to the structure and rigidity of its flexible loops. The enhanced thermostability allows A242L to tolerate higher temperatures for extended periods, driving the reaction towards lactulose production, which is suitable for industrial lactulose production under harsh conditions.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Jing Tang,Guangrong Zou,Chen Chen,Jing Ren,Fang Wang,Zilin Chen
The identification of formylpyrimidines in DNA is crucial for a better understanding of epigenetics. Although many techniques have been explored to detect their content, more accurate methods of formylpyrimidine determination are still required due to the relatively lower sensitivity or lack of selectivity in current methods. Herein, an electrochemical method based on the covalent bonding of the azido derivative of (2-benzimidazolyl) acetonitrile (azi-BIAN) and the aldehyde group of 5-formyluracil (5fU) was proposed for the selective detection of 5fU in the presence of 5-formylcytosine (5fC) and apyrimidinic (AP) sites. Target DNA containing 5fU was first treated with azi-BIAN and then incubated with DBCO-PEG4-Biotin to introduce a biotin group by copper-free click chemistry. Next, the sulfhydryl group was attached to the 5′ end of above DNA through T4 polynucleotide kinase-catalyzed reaction. Subsequently, the labeled DNA was assembled onto the AuNPs-modified glassy carbon electrode (AuNPs/GCE) through Au–S bonds, and the streptavidin–horseradish peroxidase conjugate (SA-HRP) was further immobilized onto the surface of the above electrode by specific recognition between biotin and streptavidin. Finally, HRP catalyzed hydroquinone oxidation to benzoquinone to enhance the current signal, which was related to the amount of 5fU in nucleic acids. This method demonstrated a good linear relationship with 5fU concentrations ranging from 0.1 to 10 nM. Moreover, the level of 5fU in γ-irradiated nucleic acids was also successfully detected, indicating that the combination of molecule-depended chemical recognition and electrochemical sensing is a promising method for the selective and sensitive detection of 5fU.
研究领域:
生物化学
·
分析化学
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
FEMS MICROBIOLOGY LETTERS
·
2015
·Vol. 362
·期 6
·
IF 2.121
Zhao Jianqing,Pan Shan,Lin Lan,Fu Lei,Yang Chao,Xu Zhongmin,Wei YanMin,Jin Meilin,Zhang Anding
Streptococcus suis (S. suis) ranks among the five most important porcine pathogens worldwide and occasionally threatens human health, especially in people that come into close contact with pigs or pork products. Streptococcus suis serotype 2 (SS2) is considered to be the most pathogenic and prevalent capsular type. As a first line of immune defense against SS2 infection, neutrophils can eliminate the invader not only by phagocytosis but also by neutrophil extracellular traps (NETs)-mediated killing. SS2 can resist phagocytosis through polysaccharide capsule (CPS), but how this strain evades the effects of NETs remains to be determined. The present study demonstrated that the epidemic strain 05ZY, the highly pathogenic strain P1/7 and the intermediately pathogenic strain A7 could induce the formation of NETs. Furthermore, SS2 strains could successfully resist NETs-mediated killing, and the CPS structure contributed to this resistance by escaping the trapping. Therefore, the CPS structure not only contributed to the SS2 strains’ resistance to phagocytosis-mediated killing but also played an essential role in evading NETs trapping and further killing in vitro. This study strengthens our understanding of how S. suis can evade innate immune surveillance and elimination.
研究领域:
微生物学
·
免疫学
✓ 已验证
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Yu-Xuan Dai,Wen-Li Xin,Lian-Hua Xu,Ji Li,Yi-Xuan Li,Junji Li,Serge Cosnier,Xue-Ji Zhang,Robert S. Marks,Dan Shan
Rational design highly active transition metal or transition metal oxides/nanocarbon hybrids is one of the feasible way to deliver a cooperative oxygen reduction (ORR) with a synergistic effect of the hybrid interface. Herein, based on benzimidazole-5-carboxylate (BIMC), CoO/Co-N-C nanocomposites are fabricated via 2-methylimidazole (2-MeIm)-tuned “4-Self” strategy, namely, self-templating, self-adapting, self-assembly and self-catalysis. As a base competitive ligand with N and C sources, 2-MeIm modulates the dispersion of BIMC in methanol to generate collodial-like BIMC tiny particles, the coordination ability of BIMC to Co(II), the composition and morphology of the self-assembled precursor (Co-BM), and as well as the conductivity of the resultant electrocatalyst. Impressing, carbonization of Co-BM at 800 °C under N 2 atmosphere endows the pyrolysis product (Co-BM-800) with the well-dispersed Co/CoO riveted on nitrogen-doped carbon, as well as the enhanced ORR performance in terms of positive onset-potential (0.890 V vs. RHE), large diffusion limiting current density (5.21 mA cm −2 ), and high stability.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
POSTHARVEST BIOLOGY AND TECHNOLOGY
·
2020
·
IF 4.303
Xueyin Ru,Ning Tao,Yanyan Feng,Qingqing Li,Qingguo Wang
Enzymatic browning is one of the essential issues affecting the quality of fresh-cut produce. In this study, we identified a novel, safe, and effective anti-browning agent, 3-mercapto-2-butanol, which can prevent fresh-cut potatoes from browning for 5 d under the concentration of 25 μL L −1 at 5 °C. The inhibitory effect of 3-mercapto-2-butanol was close to sodium bisulfite. 3-Mercapto-2-butanol was further identified as a competitive inhibitor which directly inhibited the activity of polyphenol oxidase (PPO) by enzyme kinetic analysis, and the expression levels of PPO-related genes ( POT32 and POT33 ) were decreased after 3-mercapto-2-butanol treatment. Besides, the concentration of enzymatic browning substrate tyrosine (Tyr) in the potato chips was found significantly higher in 3-mercapto-2-butanol treatment group than in the control group. We speculated that 3-mercapto-2-butanol could reduce the consumption of Tyr by inhibiting the activity of PPO. Our finding not only provided a novel and safe anti-browning agent candidate (3-mercapto-2-butanol) to efficiently solve the browning issue for fresh-cut food products, but also preliminarily revealed its mechanism in browning inhibition.
研究领域:
食品科学
·
植物生理学
✓ 已验证
DOI
高影响因子
MOLECULAR PHARMACEUTICS
·
2024
·
IF 4.5
Ningze Zheng,Shurui Liu,Jianheng Chen,Yue Xu,Wenyin Cao,Jinyi Lin,Guang Lu,Guigen Zhang
The development of biomolecule delivery systems is essential for the treatment of various diseases such as cancer, immunological diseases, and metabolic disorders. For the first time, we found that SARS-CoV-2-encoded nonstructural protein 2 (NSP2) can be secreted from the cells, where it is synthesized. Brefeldin A and H89, inhibitors of ER/Golgi secretion pathways, did not inhibit NSP2 secretion. NSP2 is likely secreted via an unconventional secretory pathway. Moreover, both secreted and purified NSP2 proteins were able to traverse the plasma membrane barrier and enter both immortalized human umbilical vein endothelial cells and tumor cell lines. After entry, the NSP2 protein was localized in only the cytoplasm. Cytochalasin D, a potent inhibitor of actin polymerization, inhibited the entry of NSP2. NSP2 can carry other molecules into cells. Burkholderia lethal factor 1, a monomeric toxin from the intracellular pathogen Burkholderia pseudomallei, has demonstrated antitumor activity by targeting host eukaryotic initiation translation factor 4A. An NSP2-BLF1 fusion protein was translocated across the cellular membranes of Huh7 cells and mediated cell killing. By using different approaches, including protein purification, chemical inhibition, and cell imaging, we confirm that NSP2 is able to deliver heterologous proteins into cells. NSP2 can act as a potential delivery vehicle for proteins.
研究领域:
分子生物学
·
细胞生物学
·
癌症研究
·
药理学
✓ 已验证
DOI
PubMed
高影响因子
FUEL
·
2025
·
IF 7.5
Wanpeng Li,Xuewei Zhang,Guangmai Zhao,Tianhan Zhu,Mi Luo,Tianyu Gao,Chenguang Wang,Xiaoyu Chen,Jin Tan,Yuhe Liao,Haiyong Wang
The efficient and sustainable transformation of biomass-derived furfural into value-added chemicals is a key challenge in green chemistry. In this study, a series of Pt/CeO 2 catalysts with varying Pt loadings (0.1–2.0 wt%) were synthesized via a carbonization–reduction method and applied for the selective conversion of furfural to 2-furfural diethanol in ethanol under mild conditions. Comprehensive characterization using XRD, XPS, EPR, TEM, and Py-FTIR revealed that the 1.0 wt% Pt/CeO 2 catalyst exhibited optimal properties, including high dispersion of metallic Pt⁰, abundant oxygen vacancies, enriched Ce 3+ species, and dominant Lewis acid sites. Catalytic tests demonstrated that under mild conditions (20 °C, 4 MPa N 2 ), the 1.0 wt% Pt/CeO 2 catalyst achieved the highest yield (92.17 %) and furfural conversion (95.41 %). Mechanistic studies suggest a proposed redox-driven tandem hydrogenation–condensation pathway, where the synergistic effect between Pt⁰ sites and oxygen vacancies facilitates furfural activation, hydrogen transfer, and product formation. This work provides a mechanistic understanding of furfural upgrading over Pt/metal oxide interfaces and offers a promising strategy for the rational design of high-performance catalysts for biomass valorization.
✓ 已验证
产品关联
DOI
高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2016
·Vol. 182
·期 3
·898-909
·
IF 1.606
Xu Jian-Miao,Cheng Feng,Fu Fang-Tian,Hu Hai-Feng,Zheng Yu-Guo
L -2-aminobutyric acid ( L -ABA) as a precursor for the anticonvulsant and the antituberculotic is a key intermediate in the chemical and pharmaceutical industries. Recently, leucine dehydrogenase (LeuDH) with NAD + regeneration was developed for L -ABA production on a large scale. Previously, the L -ABA yield was improved by optimizing conversion conditions, including cofactor regeneration and enzyme immobilization but not protein engineering on LeuDH due to lacking an applicable high-throughput screening (HTS) method. Recently, an HTS assay was developed by us, which enables researchers to engineer LeuDH in a relatively short period of time. Herein, a semirational engineering was performed on LeuDH to increase the catalytic efficiency of BcLeuDH. Firstly, the structure of wild-type (WT) BcLeuDH was modeled and seven potentially beneficial positions were selected for mutation. Five beneficial variants were then identified from the seven site-saturation mutagenesis (SSM) libraries by HTS and confirmed by rescreening via amino acid analyzer. The “best” variant M5 (WT + Q358N) showed 44.5-fold higher catalytic efficiency ( k
cat / K
M ) than BcLeuDH WT, which suggested that BcLeuDH M5 is an attractive candidate for L -ABA production on a large scale. Furthermore, the structure-functional relationship was investigated based on the docking and kinetic results.
研究领域:
生物技术
·
生物化工
·
酶学
·
药学
✓ 已验证
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Ruijin Zeng,Minghao Qiu,Qing Wan,Zhisheng Huang,Xiaolong Liu,Dianping Tang,Dietmar Knopp
Large-scale, rapid, and inexpensive serological diagnoses of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) are of great interest in reducing virus transmission at the population level; however, their development is greatly plagued by the lack of available point-of-care methods, leading to low detection efficiency. Herein, an ultrasensitive smartphone-based electrochemical immunoassay is reported for rapid (less than 5 min), low-cost, easy-to-implement detection of the SARS-CoV-2 nucleocapsid protein (SARS-CoV-2 N protein). Specifically, the electrochemical immunoassay was fabricated on a screen-printed carbon electrode coated with electrodeposited gold nanoparticles, followed by incubation of anti-N antibody (Ab) and bovine serum albumin as the working electrode. Accompanied by the antigen–antibody reaction between the SARS-CoV-2 N protein and the Ab, the electron transfer between the electroactive species [Fe(CN)6]3–/4– and the electrode surface is disturbed, resulting in reduced square-wave voltammetry currents at 0.075 V versus the Ag/AgCl reference electrode. The proposed immunoassay provided a good linear range with SARS-CoV-2 N protein concentrations within the scope of 0.01–1000 ng/mL (R2 = 0.9992) and the limit of detection down to 2.6 pg/mL. Moreover, the detection data are wirelessly transmitted to the interface of the smartphone, and the corresponding SARS-CoV-2 N protein concentration value is calculated and displayed. Therefore, the proposed portable detection mode offers great potential for self-differential diagnosis of residents, which will greatly facilitate the effective control and large-scale screening of virus transmission in resource-limited areas.
研究领域:
医学诊断
·
生物传感器
·
病毒学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）