INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Pei Xie,Kai Wang,Jisong Zhang,Yunpeng Hu,Guangsheng Luo
To obtain a high quality bromobutyl rubber product, a higher selectivity of brominated secondary allylic structure is necessary, but it is difficult to realize in traditional reaction devices. We developed a microreaction system and used microwater droplets as an extractant to in situ remove HBr, the catalyst of the isomerization side reaction, from the organic reacting solution to prevent converting brominated secondary allyl to brominated primary allyl and degradation of the polymer chain. The microreaction system contains two micromixers, including a membrane dispersion micromixer for dispersing microwater droplets in the butyl rubber solution and a cross-junction micromixer for blending butyl rubber and Br2 solutions. A volume adjustable delayed loop after the micromixers is used to carry out the reaction. The results show that 1 wt % water in the organic phase is satisfied to remove HBr, and 97% selectivity of brominated secondary allyl is successfully obtained under optimized operating conditions.
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PLoS One
·
2018
·Vol. 13
·期 7
·e0199110
·
IF 2.766
Yi Wang,Changan Geng,Xiaolong Yuan,Mei Hua,Fenghua Tian,Changtian Li
Usnic acid is a unique polyketide produced by lichens. To characterize usnic acid biosynthesis, the transcriptome of the usnic-acid-producing lichen-forming fungus Nephromopsis pallescens was sequenced using Illumina NextSeq technology. Seven complete non-reducing polyketide synthase genes and nine highly-reducing polyketide synthase genes were obtained through transcriptome analysis. Gene expression results obtained by qPCR and usnic acid detection with LCMS-IT-TOF showed that Nppks7 is probably involved in usnic acid biosynthesis in N . pallescens . Nppks7 is a non-reducing polyketide synthase with a MeT domain that also possesses beta-ketoacyl-ACP synthase, acyl transferase, product template, acyl carrier protein, C-methyltransferase, and Claisen cyclase domains. Phylogenetic analysis shows that Nppks7and other polyketide synthases from lichens form a unique monophyletic clade. Taken together, our data indicate that Nppks7 is a novel PKS in N . pallescens that is likely involved in usnic acid biosynthesis.
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Nature Protocols
·
2018
·Vol. 13
·期 10
·2362-2386
·
IF 12.423
Zou Yejun,Wang Aoxue,Shi Mei,Chen Xianjun,Liu Renmei,Li Ting,Zhang Chenxia,Zhang Zhuo,Zhu Linyong,Ju Zhenyu,Loscalzo Joseph,Yang Yi,Zhao Yuzheng
Cellular oxidation–reduction reactions are mainly regulated by pyridine nucleotides (NADPH/NADP + and NADH/NAD + ), thiols, and reactive oxygen species (ROS) and play central roles in cell metabolism, cellular signaling, and cell-fate decisions. A comprehensive evaluation or multiplex analysis of redox landscapes and dynamics in intact living cells is important for interrogating cell functions in both healthy and disease states; however, until recently, this goal has been limited by the lack of a complete set of redox sensors. We recently reported the development of a series of highly responsive, genetically encoded fluorescent sensors for NADPH that substantially strengthen the existing toolset of genetically encoded sensors for thiols, H 2 O 2 , and NADH redox states. By combining sensors with unique spectral properties and specific subcellular targeting domains, our approach allows simultaneous imaging of up to four different sensors. In this protocol, we first describe strategies for multiplex fluorescence imaging of these sensors in single cells; then we demonstrate how to apply these sensors to study changes in redox landscapes during the cell cycle, after macrophage activation, and in living zebrafish. This approach can be adapted to different genetically encoded fluorescent sensors and various analytical platforms such as fluorescence microscopy, high-content imaging systems, flow cytometry, and microplate readers. A typical preparation of cells or zebrafish expressing different sensors takes 2–3 d; microscopy imaging or flow-cytometry analysis can be performed within 5–60 min.
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WATER RESEARCH
·
2019
·
IF 7.913
Feilong Dong,Jianing Chen,Cong Li,Xingmao Ma,Jingjing Jiang,Qiufeng Lin,Chenhong Lin,Hongyan Diao
Disinfection is a key step in drinking water treatment process to prevent water-borne infections. However, reactions between chlorine, one of the most common disinfectants, and natural organic matter (NOM) often lead to the formation of hazardous disinfection byproducts (DBPs). However, the cytotoxicity of some DBPs is still poorly understood. Such knowledge is critical for proper selection of disinfection processes. We investigated the effects of DBPs on mouse acute liver injury. The exacerbation of liver damage increased with the DBPs concentrations, likely due to the increased hepatic macrophages. Haloacetonitriles (HANs) and haloketones (HKs) are more toxic to Human Hepatocellular (Hep3B) cells than trihalomethanes (THMs). Cytotoxicity of DBPs were governed by the halogen type (brominated DBPs > chlorinated DBPs) and the numbers of halogen atoms per molecule. Then, we used the pilot-scale WDS to study the best conditions for reducing the formation of DBPs. The result showed that the formation of DBPs followed the order: stainless-steel (SS) > ductile iron (DI) > polyethylene (PE) pipe. Higher flowrate promoted the formation of DBPs in all three pipes. The results suggest that the formation of DBPs in chlorine disinfection can be reduced by using PE pipes and low flow rate in water distribution systems (WDS).
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JOURNAL OF HAZARDOUS MATERIALS
·
2018
·
IF 6.434
Chao Qu,Shanfu Lu,Dawei Liang,Sian Chen,Yan Xiang,Shujun Zhang
During electro-oxidation (EO) wastewater treatment, the applied voltage must polarize both a dimensionally stable anode with a sufficiently high potential to effectively produce hydroxyl radicals ( OH), as well as a cathode with a sufficiently low potential to catalyze the H 2 evolution reaction (HER). Nevertheless, H 2 does not contribute to pollutant degradation and yet increases energy consumption. Inspired by fuel cell technology, in which the O 2 reduction reaction (ORR) is catalyzed on the cathode, herein, a carbon nanotube-coated carbon-PTFE gas diffusion electrode was fabricated to catalyze ORR during EO for the treatment of leachate concentrates. In comparison to conventional HER-EO, ORR-EO was shown to save 17.7–23.2% energy consumption. Further, as the cathodic ORR byproduct, H 2 O 2 can react with the ozone generated from the Ti/SnO 2 -Sb 2 O 5 anode to catalyze the peroxone process, which enhances OH generation for the degradation of organic products. This in situ electro-peroxone process was determined by salicylic acid OH trapping and liquid chromatography. The novel simultaneous EO and in situ electro-peroxone process described herein has great application potential and economic merit in the degradation of refractory organics in wastewater.
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Artificial Cells Nanomedicine and Biotechnology
·
2018
·
IF 3.026
Kaili Wang,Chunjing Guo,Shaohua Zou,Yueming Yu,Xinxin Fan,Bingjie Wang,Mengna Liu,Lei Fang,Daquan Chen
To remedy the problems resulting from the usage of anti-cancer drugs in cancer chemotherapy, such as deficient drug concentration in tumour cells, low water-solubility and non-specific distribution of antitumour drugs, a kind of reduction-sensitive polymer prodrug of curcumin (Cur) containing in the nano-echinus was synthesized and designed. The nano-echinus-like nanomedicine presented synergistic effect with glycyrrhetic acid (GA) and oligomeric hyaluronic (HA) for targeting and combating HepG2 human liver cancer cell. Firstly, a kind of small molecular prodrug of Cur, dithiodipropionic acid-Cur (-SS-Cur), was chemically conjugated onto the side chain of the conjugated glycyrrhetic acid- oligomeric hyaluronic (GA-HA) to generate an amphiphilic polymeric prodrug of Cur, GA-HA-SS-Cur. The obtained GA-HA-SS-Cur prodrug and subsidiary material mPEG-DSPE could self-assemble into a sea urchin-like micelles in aqueous media and release Cur rapidly in response to glutathion (GSH). Then, Cur was loaded into the nano-echinus with a particle size of (118.1 ± 0.2 nm) and drug-loading efficiency of (8.03 ± 2.1%). The structure of GA-HA-SS-Cur was characterized by 1H-NMR in this report. The morphology of micelles was observed with a transmission electron microscope (TEM). Subsequently, the reduction-sensitivity of the nano-echinus was confirmed by the changes in in-vitro drug release after different concentrations of GSH treatment. Besides, the cellular uptake behaviour and MTT assays of the nano-echinus were investigated, suggesting that the nano-echinus was of desirable safety and could be taken into HepG2 cells in a time-dependent manner. Later, anti-tumour efficacy in vivo revealed the effective inhibition of tumour growth.
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PHARMAZIE
·
2012
·Vol. 67
·期 12
·1002-1006
·
IF 1.006
Dong Rui-Hua,Fang Zhong-Ze,Zhu Liang-Liang,Ge Guang-Bo,Cao Yun-Feng,Li Xiao-Bao,Hu Cui-Min,Yang Ling,Liu Ze-Yuan
Carvacrol and thymol are phenolic compounds with similar structures isolated from many aromatic plants, and have been demonstrated to exert multiple pharmacological effects. The metabolic and pharmacokinetic behaviour of thymol and carvacrol has received much attention. Carvacrol and
thymol have been demonstrated to undergo phase I metabolism such as hydroxylation reaction. However, drug-metabolizing enzymes involved in this process remain unclear. Given that cytochrome P450 s (CYPs) are involved in most phase I metabolism, the aim of the present study was to investigate
the role of CYPs in the metabolism of thymol and carvacrol. After incubation with human liver microsomes (HLMs) in the presence of NADPH, a new metabolite and two metabolites were detected for thymol and carvacrol, respectively. A combination of chemical inhibition studies and assays with
recombinant CYP isoforms demonstrated that CYP2A6 was the predominant drug-metabolizing enzyme involved in the metabolism of thymol and carvacrol. All these results remind the researchers that special attention should be paid on pharmacokinetic and clinical outcomes when thymol or carvacrol
was co-administrated with other compounds mainly undergoing CYP2A6-mediated metabolism.
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Food & Function
·
2015
·Vol. 7
·期 1
·530-539
·
IF 2.791
Chun Chen,Li-Jun You,Arshad Mehmood Abbasi,Xiong Fu,Rui Hai Liu,Chao Li
The present study aimed to characterize and investigate the polysaccharide fractions of mulberry fruit, and their antioxidant and hypoglycemic activities. Mulberry fruit polysaccharides (MFP) were extracted by using hot water as the solvent and fractioned by using a DEAE-Sepharose fast-flow column. In total four eluents of water (MFP-1), 0.1 M NaCl (MFP-2), 0.2 M NaCl (MFP-3) and 0.3 M NaCl (MFP-4) were fractionated. Arabinose, galactose, glucose, xylose and mannose were the main components present in MFP-1, while MFP-2 and MFP-3 were composed of arabinose and galactose, and MFP-4 of arabinose, galactose and glucose. High-performance gel permeation chromatography (HP-GPC) analysis indicated a narrower molecular weight distribution in the MFP-1 fraction. Scanning electron microscopy (SEM) exhibited a smooth surface for MFP-1 and MFP-3 fractions, whereas MFP-2 and MFP-4 have pore openings and flocculent fibers on a smooth surface. Tertiary structure analyses indicated that none of the fractions had a triple-helical conformation. On the whole, MFP-3 and MFP-4 showed better antioxidant activity and inhibitory effects on α-amylase and α-glucosidase compared to MFP-1 and MFP-2. These results show significant potential for the antioxidant and hypoglycemic activities of MFP-3 and MFP-4 indicating the need for their further exploration as potential antidiabetic agents.
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CARBON
·
2014
·
IF 6.16
Lili Zhang,Jibin Pu,Liping Wang,Qunji Xue
The use of graphene and multi-walled carbon nanotubes (MWCNTs) additives as lubricants has received considerable interest because of their excellent mechanical and frictional properties . Given their structural differences, both carbon nano-additives are expected to have different synergistic effects at various conditions (from boundary to mixed lubrication). For applications in space, the tribological properties of graphene and MWCNTs additives in diamond-like carbon/ionic liquids hybrid films in different lubricating states at high vacuum were compared. The wear surfaces, transfer films, wear debris, and microstructures of the hybrid films were analyzed via Raman spectroscopy , X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The results showed that MWCNTs and graphene present the different nano-scale tribological mechanisms and produce different lubricating effect on the hybrid films at different lubricating states.
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IMMUNOBIOLOGY
·
2014
·
IF 3.18
Haili Qi,Hang Yang,Gang Xu,Jingli Ren,Wei Hua,Yingpeng Shi,Malvin Torsvik,Jon Florholmen,Guanglin Cui
Chronic inflammation increases colorectal cancer (CRC) risk as seen in ulcerative colitis (UC). Proinflammatory cytokines play a critical role in mediating the development of colitis associated cancer (CAC). In this study, the therapeutic efficacy of anti-interleukin (IL)-17A by anti-IL-17A antibody injection on the development of CAC was assessed in 1,2-dimethylhydrazine (DMH) plus dextran sulfate sodium (DSS) induced CAC mouse model. The results showed that mice dosed with DMH plus DSS for 10 weeks evoked high degree dysplastic lesion in the large bowel that accompanied with significant increased IL-17A expression, proliferation index and inflammation degree in mice. After anti-IL-17A antibody injection for 2 weeks, the number of tumors, proliferation index and the expression level of IL-17A protein in the large bowel tissues were significantly decreased. Therefore, we concluded that the anti-IL-17A blockade can suppress the development of CAC and is a potential therapeutic agent for the prevention of CAC in colitis mice.
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SCRIPTA MATERIALIA
·
2014
·
IF 2.968
Ben Ma,Bo Chi,Jian Pu,Jian Li
The morphology of domain structure in LaNbO 4 added to YSZ–NiO composite was examined using a focused ion beam prepared specimen in a transmission electron microscope with a straining stage. It is confirmed for the first time that the morphology is changed under load through domain boundary movement. The driving force for this domain switch is the difference in Gibbs free energy between domains with different crystallographic orientations. This domain switch improves toughness by dissipating stress build-up at the crack tips.
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ANALYTICAL CHEMISTRY
·
2015
·
IF 5.636
Jianqiao Xu,Shuyao Huang,Rongben Wu,Ruifen Jiang,Fang Zhu,Jing Wang,Gangfeng Ouyang
In this study, electrospun nanofibers were used as solid-phase microextraction (SPME) fiber coatings after substituting the water-soluble sheath of the emulsion electrospun polystyrene (PS)@Plurinic F-127 core–sheath nanofibers with biocompatible and water-stable polydopamine (PDA) and subsequently being appropriately cross-linked with glutaraldehyde (GA) to enhance the strength of the electrospun architecture. The novel custom-made PS@PDA-GA coating was wettable in aqueous solutions and thus exhibited much higher extraction efficiency than the nonsheathed PS nanofiber coating and the thicker polydimethylsiloxane (PDMS) coating. The novel coating also possessed excellent stability (relative standard deviations (RSDs) less than 7.3% for six sampling-desorption cycles), interfiber reproducibility (RSDs less than 14.3%), and antibiofouling ability, which were beneficial for in vivo sampling. The PS@PDA-GA fiber was used to monitor pharmaceuticals in dorsal-epaxial muscle of living fish, and satisfactory sensitivities with the limits of detection in the range of 1.1 (mefenamic acid) to 8.9 (fluoxetine) ng·g–1 and comparable accuracies to liquid extraction were achieved. In general, this study explored a convenient and effective method to sheath nanofibers for high-efficient in vivo SPME of analytes of interest in semisolid tissues.
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