Materials Today Chemistry
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2023
·
IF 7.3
Shiwei Feng,Chengping Zhang,Hengdao Quan
A facile, safe, and environmentally friendly preparation method is described for the synthesis of AlF x (OH) 3-x by the activation of γ-Al 2 O 3 using HCFO-1233zd( E ) under various temperatures. Comprehensive characterization techniques including XRD , XPS, N 2 sorption, SEM, TEM , 27 Al MAS NMR, FTIR, and py-IR were employed, revealing that at lower temperatures such as 275 °C and 300 °C, the synthesis yielded AlF(OH) 2 , while at higher temperatures like 350 °C and 375 °C, pyrochlore AlF 1.5 (OH) 1.5 and metastable hexagonal tungsten bronze-type (HTB) β-AlF 3 were formed, with α-AlF 3 detected at 325 °C. Notably, a significant quantity of AlF(OH) 2 can be obtained at 325 °C within a specific time frame. This amorphous phase exhibits weak Lewis acid sites and a lower acid density, rendering it significantly more effective in the isomerization of HCFO-1233zd( E ) compared to strong Lewis acid catalysts such as AlF 1.5 (OH) 1.5 and β-AlF 3 , which could promote coke formation, leading to catalyst deactivation . Moreover, due to its limited further fluorination at 290 °C, the optimal catalyst exhibits prolonged lifespan and high efficiency in HCFO-1233zd( E ) isomerization.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2021
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IF 5.279
Chen Yang,Jiajia You,Mengkai Hu,Ganfeng Yi,Rongzhen Zhang,Meijuan Xu,Minglong Shao,Taowei Yang,Xian Zhang,ZhiMing Rao
2,5-Dimethylpyrazine (2,5-DMP) is an important pharmaceutical intermediate and an important essence. Conventional chemical synthesis methods are often accompanied by toxic substances as by-products, and the biosynthesis efficiency of 2,5-DMP is insufficient for industrial applications. In this study, the tdh and soaao genes were overexpressed to enhance enzymatic and nonenzymatic reactions in metabolic pathways, and kbl was knocked out to block competitive branching carbon flow metabolic pathways. Finally, a genetically engineered Escherichia coli strain with the highest carbon recovery rate (30.18%) and the highest yield reported to date was successfully constructed, and 9.21 g·L–1 threonine was able to produce 1682 mg·L–1 2,5-DMP after 24 h. At the same time, an expression regulation strategy and whole-cell biocatalysis helped to eliminate the damage to cells caused by 2,5-DMP, aminoacetone, and reactive oxygen species generated by aminoacetone oxidase from S. oligofermentans, and the negative effect of 2-amino-3-ketobutyrate CoA ligase on the yield of 2,5-DMP in E. coli was also demonstrated.
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Science Bulletin
·
2021
·
IF 11.78
Yibing Bu,Taoyu Shen,Wenke Yang,Shiyin Yang,Ye Zhao,Hu Liu,Yanjun Zheng,Chuntai Liu,Changyu Shen
With the rapid development of wearable intelligent devices, low-cost wearable strain sensors with high sensitivity and low detection limit are urgently demanded. Meanwhile, sensing stability of sensor in wet or corrosive environments should also be considered in practical applications. Here, superhydrophobic microcracked conductive paper-based strain sensor was fabricated by coating conductive Ti 3 C 2 T x MXene on printing paper via dip-coating process and followed by depositing superhydrophobic candle soot layer on its surface. Owing to the ultrasensitive microcrack structure in the conductive coating layer induced by the mismatch of elastic modulus and thermal expansion coefficient between conductive coating layer and paper substrate during the drying process, the prepared paper-based strain sensor exhibited a high sensitivity (gauge factor, GF = 17.4) in the strain range of 0–0.6%, ultralow detection limit (0.1% strain) and good fatigue resistance over 1000 cycles towards bending deformation . Interestingly, it was also applicable for torsion deformation detection, showing excellent torsion angle dependent, repeatable and stable sensing performances. Meanwhile, it displayed brilliant waterproof, self-cleaning and corrosion-resistant properties due to the existence of micro/nano-structured and the low surface energy candle soot layer. As a result, the prepared paper-based strain sensor can effectively monitor a series of large-scale and small-scale human motions even under water environment , showing the great promising in practical harsh outdoor environments . Importantly, it also demonstrated good applicability for spatial strain distribution detection of skin upon body movement when assembled into electronic-skin (E-skin). This study will provide great guidance for the design of next generation wearable strain sensor.
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EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY
·
2020
·Vol. 123
·期 1
·2000224
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IF 2.056
Gaofeng Yuan,Mengmeng Xu,Meijuan Tan,Jian Dong,Xiaoe Chen
The study aims to investigate the effect of combined supplementation with docosahexaenoic acid (C22:6 n-3, DHA) and vitamin E (VE) on the oxidative stress and liver triglycerides (TG) accumulation induced by high-fat diet (HFD) in mice. C57BL/6J mice are fed either a control diet or an HFD for 8 weeks. Animals are supplemented with DHA, VE, or DHA + VE, respectively. Supplementation with DHA alone shows significant improvement in oxidative stress and hepatic steatosis in mice. Supplementation with DHA significantly reduces the liver TG and total cholesterol contents, and the alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, compared with the HFD. Supplementation with DHA also significantly decreases the mRNA expression level of sterol regulatory element-binding protein 1C. However, supplementation with VE alone does not show improvement in oxidative stress and hepatic steatosis. DHA + VE supply obtains a superior effect in alleviation of hepatic steatosis than DHA supplementation alone in mice fed by HFD. The efficacy of DHA potentiated by VE can be due to that VE enhances the effect of DHA in decrease of ALT and AST levels and increase of antioxidant enzyme activity and glutathione level in mice fed by HFD. Practical Applications : Supplementation with DHA significantly improves the oxidative stress and hepatic steatosis induced by HFD in mice. The efficacy of DHA in the alleviation of hepatic steatosis induced by HFD is potentiated by VE. These findings may provide a rational basis for the use of DHA and VE co-supplementation in patients with liver steatosis.
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ANALYTICAL CHEMISTRY
·
2020
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IF 6.785
Yu Wang,Yu Xue,Shuang Wang,Jianshe Huang,Xiurong Yang
One of the pathogenesis hypotheses of Alzheimer’s disease (AD) is amyloid depositions and neurofibrillary tangles. Apolipoprotein E (Apo E) acts a vital part in the development of AD by affecting the aggregation and clearance of amyloid-β (Aβ). In this paper, a dual polarization interferometry (DPI) technique was employed for a real-time investigation toward the binding events of Apo E isoforms, for instance, Apo E2, Apo E3, and Apo E4, with Aβ1–40. By evaluation of detailed binding information provided by DPI, the affinities between Apo E isoforms and Aβ1–40 follow the order of E4 > E3 > E2, and the dissociation constants (KD) of Aβ1–40 with Apo E2, Apo E3, and Apo E4 were determined to be 251 ± 37, 40 ± 0.65, and 24.6 ± 2.42 nM, respectively. Our findings reveal the isoform-specific binding behaviors from a kinetics perspective, which can help us understand that Apo E4 has a higher risk of causing AD because of its promoting effect on Aβ aggregation and fibrillation and inefficient clearance of Aβ. Remarkably, this work provides a promising method for exploring the dynamics of interactions between biomolecules and expectantly contributes to the development of AD drugs and therapies targeting Apo E and Aβ.
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MOLECULES
·
2020
·Vol. 25
·期 3
·654
·
IF 3.267
Dongmei Ke,Wenxue Chen,Weijun Chen,Yong-Huan Yun,Qiuping Zhong,Xiaotang Su,Haiming Chen
Vitamin E (VE) and β-cyclodextrin (β-CD) can form an inclusion complex; however, the inclusion rate is low because of the weak interaction between VE and β-CD. The results of a molecular docking study showed that the oxygen atom in the five-membered ring of octenyl succinic anhydride (OSA) formed a strong hydrogen bond interaction (1.89 Å) with the hydrogen atom in the hydroxyl group of C-6. Therefore, β-CD was modified using OSA to produce octenyl succinic-β-cyclodextrin (OCD). The inclusion complexes were then prepared using OCD with VE. The properties of the inclusion complex were investigated by Fourier-transform infrared spectroscopy (FT-IR),13C CP/MAS NMR, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results demonstrated that VE had been embedded into the cavity of OCD. Furthermore, the emulsifying properties (particle size distribution, ζ-potential, and creaming index) of the OCD/VE inclusion-complex-stabilized emulsion were compared with that stabilized by β-CD, OCD, and an OCD/VE physical mixture. The results showed that the introduction of the OS group and VE could improve the physical stability of the emulsion. In addition, the OCD/VE inclusion complex showed the strongest ability to protect the oil in the emulsion from oxidation. OCD/VE inclusion complex was able to improve the physical and oxidative stability of the emulsion, which is of great significance to the food industry.Keywords:octenyl succinic β-cyclodextrin;vitamin E;inclusion complex;emulsifying property;oxidation stability
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SENSORS AND ACTUATORS B-CHEMICAL
·
2020
·
IF 7.1
Xiaoyan Zhang,Tingting Wu,Yuemeng Yang,Yongqiang Wen,Shutao Wang,Li-Ping Xu
Superwettable microchips exhibit excellent ability to anchor microdroplets and great potential in ultratrace sample detection. Herein, we present a superwettable electrochemical biosensor based on a dual-DNA walker strategy (dual-DW biosensor) for the attomolar detection of food-borne microorganisms ssDNA in microdroplets. In the presence of the target E. coli O157: H7 ssDNA, the blocked walking probe is activated as the first-step DNA walker. With the aid of the Nt.BsmAI nicking endonuclease, the partial sequence of the basal probe was released, thus achieving the first-step signal amplification. Then the hairpin probe 1(H1) was opened by the released basal probe and followed by the autonomous strand displacement of the ferrocene (Fc) labeled hairpin probe 2 (H2) and movement of the basal probe. Under optimized conditions, the dual-DNA walker strategy finally renders the dual-DW biosensor an ultrahigh sensitivity of 30 aM toward E. coli O157: H7 ssDNA and a broad detection linear range. The dual-DW biosensor also enables successful analysis of trace amount of E. coli O157: H7 ssDNA in real food samples. The superwettable electrochemical biosensor based on a dual-DNA walker strategy is expected to be a versatile tool for ultratrace DNA detection and be promising in food analysis.
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METABOLIC ENGINEERING
·
2020
·
IF 7.263
Xi Deng,Liuqing Chen,Mohan Hei,Tiangang Liu,Yan Feng,Guang-Yu Yang
Medium-chain fatty acids (C6–C10) have attracted much attention recently for their unique properties compared to their long-chain counterparts, including low melting points and relatively higher carbon conversion yield. Thioesterase enzymes , which can catalyze the hydrolysis of acyl-ACP (acyl carrier protein) to release free fatty acids (FAs), regulate both overall FA yields and acyl chain length distributions in bacterial and yeast fermentation cultures. These enzymes typically prefer longer chain substrates. Herein, seeking to increase bacterial production of MCFAs, we conducted structure-guided mutational screening of multiple residues in the substrate-binding pocket of the E. coli thioesterase enzyme ‘TesA. Confirming our hypothesis that enhancing substrate selectivity for medium-chain acyl substrates would promote overall MCFA production, we found that replacement of residues lining the bottom of the pocket with more hydrophobic residues strongly promoted the C8 substrate selectivity of ‘TesA. Specifically, two rounds of saturation mutagenesis led to the identification of the ‘TesA RD−2 variant that exhibited a 133-fold increase in selectivity for the C8-ACP substrate as compared to C16-ACP substrate. Moreover, the recombinant expression of this variant in an E. coli strain with a blocked β -oxidation pathway led to a 1030% increase in the in vivo octanoic acid (C8) production titer. When this strain was fermented in a 5-L fed-batch bioreactor , it produced 2.7 g/L of free C8 (45%, molar fraction) and 7.9 g/L of total free FAs, which is the highest-to-date free C8 titer to date reported using the E. coli type II fatty acid synthetic pathway. Thus, reshaping the substrate binding pocket of a bacterial thioesterase enzyme by manipulating the hydrophobicity of multiple residues altered the substrate selectivity and therefore fatty acid product distributions in cells. Our study demonstrates the relevance of this strategy for increasing titers of industrially attractive MCFAs as fermentation products.
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Acta Biomaterialia
·
2021
·
IF 8.947
Ri-Tong Lan,Yue Ren,Xin Wei,Li-Zhi Tang,Nouman Ali Shah,Lu Xu,Shi-Shu Huang,Rizwan M. Gul,Jia-Zhuang Xu,Zhong-Ming Li
Oxidative stability of radiation crosslinked ultrahigh molecular weight polyethylene (UHMWPE) artificial joints is significantly improved by vitamin E (VE), but there is a dilemma that VE hinders crosslinking and thus jeopardizes the wear of UHMWPE. In this effort, we proposed an efficient strategy to stabilize UHMWPE under limited antioxidant contents, where VE and D-sorbitol (DS) were used as the primary antioxidant and the secondary antioxidant respectively. For non-irradiated blends with fixed antioxidant contents, oxidative stability accessed by oxidation induction time (OIT) of VE/DS/UHMWPE blends was superior to that of VE/UHMWPE blends, while DS/UHMWPE blends showed no increase in OIT. The cooperation between DS and VE exhibited a synergistic effect on enhancing the oxidative stability of UHMWPE. Interestingly, the irradiated VE/DS/UHMWPE blends showed comparable OIT but a significantly higher crosslink density than the irradiated VE/UHMWPE blends. The crystallinity, melting point, and in vitro biocompatibility of the blends were not affected by VE and DS. The quantitative relationships of mechanical properties , oxidation stability, crystallinity and crosslink density were established to unveil the correlation of these key factors. The overall properties of VE/UHMWPE and VE/DS/UHMWPE blends were compared to elucidate the superiority of the antioxidant compounding strategy. These findings provide a paradigm to break the trade-off between oxidative stability, crosslink density and mechanical properties, which is constructive to develop UHMWPE bearings with upgraded performance for total joint replacements. Statement of significance VE-stabilized UHMWPE is the most commonly used material in total joint replacements at present. However, oxidation and wear resistance of VE/UHMWPE implants cannot be unified since VE reduces the efficiency of radiation crosslinking. It limits the use of VE. Herein, we proposed a compounding stabilization by the synergy between VE and DS. The antioxidation capability of VE was revived by DS, thus enhancing the oxidation stability of unirradiated UHMWPE. The irradiated VE/DS/UHMWPE exhibited similar oxidation stability but higher crosslink density than irradiated VE/UHMWPE, which is beneficial to combat wear of UHMWPE and to inhibit the occurrence of osteolysis . This synergistic antioxidation strategy endows the UHMWPE joint material with good overall performance, which is of clinical significance.
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EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES
·
2019
·
IF 3.532
Lin Hou,Chunyu Tian,Dandan Chen,Yujie Yuan,Yingshan Yan,Qianxiao Huang,Huijuan Zhang,Zhenzhong Zhang
Multidrug resistance (MDR) is a major reason for anticancer chemotherapy failure, and P-glycoprotein (P-gp) over-expressing on tumor cells is considered as the important target to overcome MDR. Emerging reports have showed that vitamin E (VE) can cause significant reversal of MDR due to inhibition of ATPase activity . Accordingly, we synthesized hyaluronic acid (HA) conjugated vitamin E succinate (VES) polymer, which can self-assemble into micelles and thus achieve high drug (paclitaxel (PTX) used as model drug) encapsulation as well as tumor accumulation owing to the enhanced permeability and retention (EPR) effect and HA active targeting ability. In addition, the linker between HA and VES utilized in this work was disulfide bond with reduction-sensitive property, which would respond to high glutathione (GSH) concentration in tumor cytoplasmic environment and trigger HA-CYS-VES polymer disassociation and drug release. In vitro , PTX loaded HA-CYS-VES demonstrated enhanced cytotoxicity, high apoptosis-inducing activities and reversal effects of PTX on MCF-7/Adr cells, compared to PTX. Also, cellular uptake and intracellular PTX accumulation tests displayed that PTX loaded HA-CYS-VES could more efficiently enter tumor cells and selectively release drug in cytosol so as to facilitate its function on microtubule. More importantly, PTX loaded HA-CYS-VES showed better tumor targeting ability, improved antitumor efficacy and low adverse effects on tumor-bearing mice. In conclusion, PTX loaded HA-CYS-VES exhibited a great potential for reversing MDR in anticancer chemotherapeutics.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xiaolan Zhou,Dong Xu,Yuancai Chen,Yongyou Hu
Mn/Fe@porous carbon (PC) was successfully fabricated through a simple carbonization of Mn-doped MIL-53(Fe) precursor and used as cathode modification in hydroxyl radical ( OH) based heterogeneous electro-Fenton (hetero-EF) process for triclosan (TCS) degradation. With co-doping of bimetal (Mn and Fe) in porous carbon, Mn/Fe@PC could markedly enhance the electrocatalysis with low oxygen reduction potential, high electrochemical active area and low resistance. Mn/Fe@PC modified cathode showed high electrocatalytic activity, great stability and low energy consumption (1.92 kWh m −1 and 0.63 kWh log −1 m −3 ) for TCS degradation over a wide pH range. The complete TCS degradation within 120 min and a 56.9 ± 2.0% TOC removal within 240 min were achieved under the condition of current 40 mA and initial pH 3. Based on the CV curves, the more negative reductive peak of Fe and Mn revealed the kinetically beneficial regeneration of Fe II /Mn II/III in Mn/Fe@PC. The electron transfer between Fe II/III and Mn II/III/IV , together with the direct regeneration of Fe II / Mn II/III on the cathode, could markedly promote the utilization of H 2 O 2, eventually leading to facilitating TCS degradation. According to the GC–MS intermediates, the possible TCS degradation pathway was deduced, including hydroxylation and dehalogenation attacked by OH. Furthermore, the TCS degradation experiments were also performed in different water matrix including river water, tap water and municipal sewage, indicating the feasibility of the TCS degradation in actual waters with Mn/Fe@PC-CP cathode in hetero-EF process. The toxicity analysis indicated that the hetero-EF process could achieve the TCS degradation and toxicity reducing.
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CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Hui Wang,Yanwen Shen,Ziyang Lou,Nanwen Zhu,Haiping Yuan,Chunnan Liu
Concentrated leachate is collected from two-stage anaerobic/aerobic-membrane bioreactor (MBR) and nanofiltration (NF) unit in landfill leachate treatment process and featured with non-biodegradation compounds and high salts content. E + -ozonation process was developed and introduced to deal with concentrated leachate, to make good use of chlorine ions (Cl − ) and the associated O 2 during ozonation process. 74.5% and 69.7% of COD and TOC were removed in E + -ozonation under the optimum conditions with initial pH of 9 and current density of 30 mA∙cm −2 , and the corresponding enhancement factors were 1.36 and 1.13, compared to the sum of the electrolysis and ozonation individual. The co-generation of reactive oxygen species (ROS) and reactive chlorine species (RCS) made a complementary effect on the degradation of refractory substances presented in concentrated leachate. 10.1% of total COD removal was improved by non-radical RCS generated in situ and 6.5% of total COD removal was achieved by ● OH-enhanced and Cl /ClO -emerged. With the help of electrolysis, the OH quencher of Cl − was converted into non-radical RCS (such as Cl − , ClO − and Cl 2 ) at anode, and the un-reacted O 2 /O 3 was reduced into OH at the cathode simultaneously. E + -ozonation offers a synergetic degradation potential for special wastewater with refractory matters and high Cl − content.
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