JOURNAL OF HAZARDOUS MATERIALS
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2024
·
IF 12.2
Bingyan Sun,Haifeng Xu,Tan Li,Wenjie Guan,Kaige Wang
Upcycling waste plastic into aromatics presents an attractive strategy to tackle both plastic pollution and energy challenges. However, previous studies often rely on high temperatures, precious metals, and have broad product distributions. In this study, we reported that a Ni/ZSM-5 bifunctional catalyst can directly convert polyethylene (PE) into methylated aromatics with high selectivity under mild conditions, while eliminating the requirement for hydrogen gas and solvents. The liquid yield could attain up to 70.3 %, and the aromatics yield could achieve up to 51.7 %. Over 78.4 % of the aromatics were methylated aromatics including toluene, xylene, and mesitylene. Polymer chains underwent dehydrogenation over Ni and the acid sites in ZSM-5, forming C C bonds. Certain of these bonds evolved into carbenium ions through the process of proton transfer at the acid sites. The optimization of Ni and acid sites enhanced the oligomerization, cyclization, and aromatization process. The extra mesopores created by Ni on the molecular sieve aid in the generation of aromatics. Furthermore, the Ni/ZSM-5 catalyst demonstrated the ability to convert typical commercial grades of PE plastic, such as gloves and bottles, into aromatics with a selectivity of up to 61.1 %. It offers an economically feasible and environmentally friendly upcycling avenue for the circular economy of plastics.
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Molecular Catalysis
·
2024
·
IF 3.9
Yan-Fei Liang,Shuai Feng,Dan Wu,Meng Ma,Jin-Tao Ren,Qian Zhao,Wen-Yun Gao,Heng Li
1-Deoxy- D- xylulose-5-phosphate synthase (DXS) is the first rate-limiting enzyme in the 2-methyl- D- erythritol-4-phosphate (MEP) terpenoid biosynthetic pathway. To explore the active sites of the protein, we made a series of mutations to the key amino acid residues of Escherichia coli DXS including H49, R420, D427, and R478. The results show that several mutants including H49Q lose almost all their catalytic activity in DXP synthesis, but the double-point mutants H49QD427H and H49QD427 N recover 100 % activity of the wild type enzyme. The kinetic characterization displays that the affinity of the double-point mutants for pyruvate and D- glyceraldehyde-3-phosphate only slightly decreases. We also assessed impact of the mutation on the oxidative decarboxylation activity of all the mutants. Despite the fact that H49QD427H and H49QD427 N get back the full activity with regard to DXP synthesis, their oxidase activity remains unrestored. Furthermore, we assayed the acceptor substrate spectrum of the mutants and the results show that a large portion of them catalyzes ligation between pyruvate and nitrosobenzene to form N-phenyl-N-hydroxyacetamide, whereas R420D, R420F, and D427H exhibit activity in connection of pyruvate and benzaldehyde to afford phenylacetocarbinol (PAC), with the first two mutants yielding ( S )-PAC (yields 21 %-25 %, ee values 71–75 %) while D427H furnishing ( R )-PAC (yield 41 %, ee value 91 %), implying the key role of D427 for the acceptor substrate recognition and the stereoselectivity of the enzyme. It is worth noting that this is the first report of DXS mutants that can recognize benzaldehyde as an acceptor substrate and generate both enantiomers of PAC.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
·
IF 7.7
Tianxu Liu,Ismail Muhammad Asif,Lichong Liu,Minghui Zhang,Bin Li,Ling Wang
Visceral and somatic hypersensitivity is a common cause of functional dyspepsia. Marine bioactive components have been revealed to possess numerous valuable abilities. However, as a kind of polysaccharide extracted from brown algae, the study focused on the biological properties of laminarin is still limited, especially in gastrointestinal disorders. In our study, indicators associated with visceral sensational function and gastrointestinal microecology were determined to investigate the modulatory effects of laminarin on functional dyspepsia induced by iodoacetamide. Mice with visceral hypersensitivity were orally administrated with laminarin (50 and 100 mg per kg bw) for fourteen days. The results indicated that laminarin partly alleviated the dysfunction by regulating corticosterone secretion, the expression of 5HT 3 receptors at both protein and mRNA levels, and mechanical transduction through the PIEZO2-EPAC1 axis. Furthermore, laminarin administration moderated the imbalanced gut microbial profile, including modulating the abundance of Bacteroidetes and Firmicutes. Our findings revealed that laminarin may restore the overexpression of 5HT 3 receptors, the abnormal mechanical transduction, and impaired gut microecology. In conclusion, we provide evidence to support the utilization of laminarin as the ingredient of complementary and alternative medicine of regulating visceral and somatic hypersensitivity.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
·
IF 4.9
Yingjie Yuan,Xiangzhen Chen,Lei Jia,Yongxin Li,Dan Zhao,Lina Zhang,Yuanyuan Huang,Jun Xu,Tongqian Zhao
Long-term discharge of tetracycline (TC) in the environment exerts selective pressure on the bacteria, increasing resistance in sensitive bacteria and posing a serious threat to public health. Therefore, it is crucial to develop real-time detection of tetracycline. In this study, we reported a novel rare-earth fluorescent nanosensor FITC-GMP-Eu, based on the formation of guanosine-5′-monophosphate disodium salt (GMP) and fluorescein isothiocyanate (FITC), which enabled the real-time identification of tetracycline in the environment. When there was no TC in the environmental sample, the FITC-GMP-Eu nanosensor exhibited the green fluorescence of FITC due to the fluorescence quenching effect of water molecules on Eu 3+ . When the environmental samples contained TC, the red fluorescence of Eu 3+ could be sensitized due to the diketone structure in the tetracycline molecule, which enabled the naked-eye visualized identification of TC. The nanosensor had high sensitivity (detection limit of 19 nM) and a wide detection range (0–30 μM) for TC. At the same time, the sensor was characterized by high visualization and anti-interference ability due to the strong fluorescence of both FITC and Eu complexes. In order to improve the practicality of the detection, this study also prepared a paper-based and sodium alginate gelated fluorescence detection platform with low background fluorescence. Combined with the common color analysis and RGB extraction procedures in mobile phones, real-time and on-site identification of TC on the surface of various fruit samples can be achieved.
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ChemSusChem
·
2024
·
IF 7.5
Xingyu Luo,Cheng Xie,Zhefei Zhao,Meiqin Shi,Huajun Zheng
Graphical Volcano plots are highly effective for understanding catalyst mechanisms and rational designing high-performance catalysts, particularly across different metals. However, the understanding of the relationship between different metals and their reaction mechanisms in 5-Hydroxymethylfurfural (HMF) reduction reactions is still limited. In this study, we explore the Gibbs free diagram of HMF reduction reactions on different metal surfaces and construct a volcano plot that connects HMF adsorption energy with the energy barriers of the rate-determining step. This provides a deeper understanding of HMFRR. Our theoretical findings align well with experimental results. Furthermore, we selectively constructed an AgPb bimetal interface based on our volcano plot, which boosted the catalyst activity. DFT calculations revealed that the AgPb bimetal surface effectively adjusts HMF adsorption energy and reduces energy barriers, suggesting that rational designing bimetal catalysts based on volcano plots is efficient. 2,5-bis(hydroxymethyl)furan (BHMF) derived from 5-Hydroxymethylfurfural (HMF) through a hydrogenation process has extensive applications in the production of resins, polymers, and artificial fibers. However, screening out the candidate and then modulating the active site to optimize the catalyst for high yield of BHMF are currently insufficient. In this study, Gibbs free energy diagrams of the reduction of HMF on 13 metals were presented, along with the identification of the rate-determining step (RDS) with the highest reaction barrier for each metal. We attempted to construct a volcano plot for HMFRR reaction. Additionally, a strategy was proposed to adjust the reaction barriers of RDS by combining two appropriate metals. Further experiments confirmed that Pb with the lowest energy barrier exhibited the highest HMF conversion (BHMF selectivity) among single metals. The modified catalyst by doping Ag on Pb, further boosted the HMF conversion (BHMF selectivity) from 42.1 % (59.4 %) to 80.8 % (80.9 %), respectively. These results provide an approach to rationally design and construct the catalyst system for efficient conversion of HMF.
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ACS Catalysis
·
2024
·
IF 11.3
Wei Gao,Guodong Qi,Chao Wang,Qiang Wang,Jiawei Liang,Jun Xu,Feng Deng
The co-aromatization of methane and organic compounds using metal-modified zeolite catalysts represents a promising approach for the direct conversion of natural gas into valuable aromatics. In this work, we employ solid-state nuclear magnetic resonance (NMR) spectroscopy to systematically examine the reaction mechanism and evaluate the impact of co-feeding furan on methane aromatization over Mo/ZSM-5 zeolite. The results reveal a dual role of furan in promoting methane to aromatics and stabilizing the Mo/ZSM-5 zeolite catalyst in the co-aromatization. It is found that co-feeding a moderate amount of furan enhances methane conversion and boosts the selectivity to benzene, toluene, and xylene (BTX). The 12C/13C isotope switching experiments coupled with 1H and 13C MAS NMR spectroscopy reveal that furan actively participates in the methane aromatization reaction by forming an olefin pool, which promotes methane activation and contributes to the following aromatics formation. Two-dimensional 1H–95Mo heteronuclear correlation NMR spectroscopy indicates that furan facilitates the activation of Mo oxides into MoOxCy species, which serve as the active sites for methane aromatization. The co-feeding furan also helps to enhance catalyst stability by limiting the agglomeration of Mo and the deposition of coking species.
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MOLECULES
·
2024
·Vol. 29
·期 17
·4051
·
IF 4.2
Chunxia Qi,Ang Li,Baoming Wu,Peisan Wang
Multifunctional targeted drug delivery systems have been explored as a novel cancer treatment strategy to overcome limitations of traditional chemotherapy. The combination of photodynamic therapy and chemotherapy has been shown to enhance efficacy, but the phototoxicity of traditional photosensitizers is a challenge. In this study, we prepared a multi-sensitive composite hydrogel containing gold nanoclusters (Au NCs) and the temperature-sensitive antitumor drug 5-fluorourac il (5-FU) using carboxymethyl cellulose (Carr) as a dual-functional template. Au NCs were synthesized using sodium borohydride as a reducing agent and potassium as a promoter. The resulting Au NCs were embedded in the Carr hydrogel, which was then conjugated with lactobionic acid (LA) as a targeting ligand. The resulting Au NCs/5-FU@Carr-LA composite hydrogel was used for synergistic photodynamic therapy (PDT), photothermal therapy (PTT), and chemotherapy. Au NCs/5-FU@Carr-LA releases the drug faster at pH 5.0 due to the acid sensitivity of the Carr polymer chain. In addition, at 50 °C, the release rate of Au NCs/5-FU@Carr-LA is 78.2%, indicating that the higher temperature generated by the photothermal effect is conducive to the degradation of Carr polymer chains. The Carr hydrogel stabilized the Au NCs and acted as a matrix for drug loading, and the LA ligand facilitated targeted delivery to tumor cells. The composite hydrogel exhibited excellent biocompatibility and synergistic antitumor efficacy, as demonstrated by in vitro and in vivo experiments. In addition, the hydrogel had thermal imaging capabilities, making it a promising multifunctional platform for targeted cancer therapy.
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Russian Journal of Physical Chemistry A
·
2024
·Vol. 98
·期 10
·2219-2232
·
IF 0.7
Guiling Wu,Zhao Wenli,Yang Xinyue,Niu Xiaopo,Guo Zhen,Liu Danni,Wang Qingfa
Abstract Producing high-density fuel of alkylated decalins from hydrodeoxygenation (HDO) of naphthalene derivatives is an environmentally friendly but still challenging method. Herein, a bifunctional Ru/HZSM-5 catalyst was fabricated by acid treatment (citric acid, oxalic acid, nitric acid) to effectively synthesize the alkylated decalins via HDO of naphthalene derivative. Acid treatment adjusted the acidic site distribution of Ru/HZSM-5. Nitric acid treatment (NA) resulted in more abundance of weak acidic sites which was beneficial for the dehydration process in HDO, and the lowest ratio of BAS/LAS to promote the hydrogenation of alkylated octalins, the rate-determining step of HDO. NA-treated Ru/HZSM-5 showed the highest HDO activity with the highest selectivity of 1,2-dimethyldecalin (74%). Besides, it also presents good HDO activity of naphthalene derivatives to produce high-density hydrocarbons. Therefore, Ru/HZ5-NA is a promising catalyst for the production of alkylated decalins and other high-value biofuels and chemicals.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2024
·Vol. 171
·期 9
·096505
·
IF 3.1
Zhefei Zhao,Linlin Zhang,Minghao Chen,Ruopeng Yu,Xuyao Yao,Yinghua Xu,Youqun Chu,Xinbiao Mao,Huajun Zheng
Electrochemical selective dechlorination can be regarded as one of the most promising strategies for generating high-valued chemicals. In the electrochemical dechlorination process of 2-chloro-5-trichloromethylpyridine (TCMP), except the anticipated dechlorination products involving 2-chloro-5-dichloromethylpyridine (DCMP), 2-chloro-5-chloromethylpyridine (CCMP), and 2-chloro-5-methylpyridine (CMP), some unexpected oxygen-incorporated products (6-chloronicotinic acid (CNA) and 6-chloronicotinoyl methyl ester (MCN)) can be obtained. Consequently, understanding the electrochemical dechlorination behavior of TCMP is crucial. Our research revealed that the activated Ag electrodes in halide ion solution exhibit enhanced electrochemical activities for electrochemical dechlorination of TCMP, compared with the pure Ag owing to the increased active specific surface areas and charge transfer. Second, oxygen participation in the reaction is a necessary condition for the formation of oxygen-incorporated products. A 100% selectivity of oxygen-incorporated products can be obtained at the potential of −0.6 V vs Ag/AgCl. Conversely, insufficient oxygen may lead to the potential becoming the determining condition that affects the reaction pathways. A more negative potential (−1.2 V vs Ag/AgCl) is conducive to the formation of dechlorination products with 94.2% conversion and 100% selectivity. This study, for the first time, elucidates the electrocatalyst, atmosphere, and potential-dependent activity and selectivity for the two dechlorination pathways of TCMP.
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RSC Advances
·
2018
·Vol. 8
·期 5
·2561-2574
·
IF 2.936
Yan Yan,Jinyao Sun,Xianting Xie,Pengchong Wang,Ying Sun,Yalin Dong,Jianfeng Xing
The aim of this study was to design and synthesize four colon-targeting mutual prodrugs of 5-aminosalicylic acid (5-ASA) and butyrate, and evaluate their therapeutic effects on ulcerative colitis. Herein, 5-ASB, 5-ASDB, Ols-DB and Ols-DBP were prepared and characterized, and their lipophilicity, solubility, in vitro and in vivo stability were investigated. Finally, the ameliorative effects of the prodrugs on experimental colitis were evaluated via a series of indicators, including the body weight and survival rates of mice, the colon index and colonic damage score, the disease activity index, the myeloperoxidase activity and levels of superoxide dismutase, malondialdehyde, glutathione and glutathione peroxidase in colonic tissues. As a result, 5-ASB was very stable but Ols-DB showed extreme instability in the environment of the gastrointestinal tract, while 5-ASDB and Ols-DBP showed desirable colon-targeting properties. The four prodrugs all had certain therapeutic effects on the experimental colitis. When orally administered to mice, 5-ASDB and Ols-DBP had significantly greater effects than the mixture of 5-ASA and sodium butyrate. Ols-DB was used as an enema and could be as effective as 5-ASDB and Ols-DBP. In addition, the therapeutic effects of the synthesized prodrugs might be associated with their anti-oxidative damage ability.
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FUEL
·
2018
·
IF 4.908
Tao Chen,Lincai Peng,Xin Yu,Liang He
A series of carbonaceous solid acid catalysts were prepared by facile carbonization and sulfonation of biorenewable feedstocks (i.e., glucose, sucrose, starch and cellulose), and employed for directly converting carbohydrates in ethanol medium to synthesize 5-ethoxymethylfurfural (EMF). The carbonization temperature of cellulose and starch (500 °C) was required to be higher than that of glucose and sucrose (400 °C) to realize high –SO 3 H density and EMF yield. Based on rich exploitability of cellulose and good activity of its derived carbonaceous catalyst, magnetic cellulose-derived carbonaceous solid acid (MCC-SO 3 H) was subsequently synthesized, which possessed a porous structure with BET surface area of 35.34 m 2 g –1 , high –SO 3 H density (1.28 mmol g –1 ) and sufficient magnetism for separation (1.99 emu g –1 ). By optimizing the process variables, a maximum EMF yield of 63.2% could be achieved from fructose at 120 °C, and ethyl levulinate formation was favored at elevated temperature. The MCC-SO 3 H catalyst could be readily separated from the reaction mixture by an external magnet with recovery rate of 92.6% after six successive runs, and reused repeatedly with little deactivation. Besides, this catalyst was efficient for the one-pot transformation of fructose-based polysaccharides into EMF, affording yields of 51.3% and 32.5% from inulin and sucrose, respectively. With glucose as the substrate, instead ethyl glucoside with a high yield of 86.5% was obtained.
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TALANTA
·
2018
·
IF 4.244
JingHong Li,Nan Chen,YiPing Tian,Hui Xu
The exploration of volatile organic compounds (VOCs) produced by cell lines may be a powerful and non-invasive tool for the study of the health risk of human exposure to atmospheric particulate matter (PM). In this work, we developed a sensitive solid phase microextraction-gas chromatography-mass spectrometry method (SPME-GC-MS) to analyze VOCs in breathed gas of PM2.5-induced human embryonic fibroblast cell line (MRC-5). A novel graphene oxide/polyaniline/polydopamine (GO/PANI/PDA) coating was prepared on a stainless steel wire via electrochemical deposition and self-polymerization for the first time. The GO/PANI/PDA coating exhibited high extraction efficiency, good thermal stability (> 380 ℃), excellent mechanical stability as well as long service time (> 150 times). Parameters that may affect the results were optimized systematically. Under the optimal conditions, VOCs including benzene series, aldehydes and alkane were detected with low limit of detection (0.2–2.0 μg L −1 ) and good correlation (correlation coefficients above 0.9922). The relative standard deviations of within-day and between-day were 1.1–8.4% and 0.2–11.2%, respectively. Satisfactory recoveries of 82–117% indicated good repeatability of the method. The method has been successfully applied for the determination of target VOCs in the headspace gas of PM2.5-induced MRC-5 cell. And it is expected to provide an alternative tool for the study of cytotoxicology of atmospheric particulates.
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