Preparation and Properties Characterization of Interpenetrating Polymer Networks/Organically Modified Montmorillonite/Scrap Leather Fibers Composites

Xinfeng Wu,Zehui Duan,Ying Wang,Yuan Gao,Kai Sun,Runhua Fan,Xiaofeng Li 한국섬유공학회 2019 Fibers and polymers Vol.20 No.9

An interpenetrating polymer networks (IPNs) based on the anhydride-cured cycloaliphatic epoxy and the trifunctionalacrylate resin cross-linked by peroxide was modified by incorporation of organic montmorillonites (OMMTs) andscrap leather fibers (SLFs). OMMTs and SLFs were introduced into IPNs via a violently mechanical stirring technique whichprovided a very well-dispersed phase of OMMTs and SLFs in matrix. Non-isothermal curing behaviors of IPNs/OMMTs/SLFs composites were investigated by means of the differential scanning calorimeter (DSC). The results of DSC testsshowed that the introduction of OMMTs and SLFs into IPNs accelerated the curing reaction of epoxy systems. In comparisonwith the case of the pristine IPNs, the thermal stability properties, the glass transition temperature, mechanical properties ofIPNs/OMMTs/SLFs composites were markedly enhanced. A desirable toughening-strengthening balance of the compositeshad been obtained at 5 pbw(parts by weight) of OMMTs and 0.5 pbw of SLFs. Significant improvements in performances ofIPNs/OMMTs/SLFs composites obtained through the addition of OMMTs and SLFs in IPNs matrix were associated withtheir good co-reinforcement and co-dispersion effects. The macroscopic properties of the composites were found to bestrongly dependent on their concentrations, components, dispersion, and the resulted morphological structures.

Preparation and Investigation of Epoxy Syntactic Foam (Epoxy/Graphite Reinforced Hollow Epoxy Macrosphere/Hollow Glass Microsphere Composite)

Xinfeng Wu,Bo Tang,Jinhong Yu,Xiao Cao,Chongyin Zhang,Yonggen Lv 한국섬유공학회 2018 Fibers and polymers Vol.19 No.1

Graphite reinforced hollow epoxy macrospheres (GR-HEMS) and hollow glass microspheres (HGMS) were used to prepare three phase epoxy syntactic foam (ESF) using “molding method”, and the physical and mechanical properties of ESF were also studied and investigated. An innovative “rolling ball method” was implemented in the GR-HEMS preparationprocess. The performance tests show that higher GR-HEMS stacking volume fraction, lower GR-HEMS thickness, higher GR-HEMS diameter, higher HGMS volume fraction, lower HGMS density are beneficial to reducing the density of ESF, but the effects of the five factors on the strength of ESF are the opposite. Therefore, in order to obtain “high strength and low density” ESF composites, the various factors should be considered to achieve a balance of the strength and the density. Scanning electron microscope (SEM) shows that the “rolling ball method” can make graphite form a graphite spherical x-y network throughout the macrosphere wall, which can make GR-HEMS and ESF have great compressive strength. The ESF (450 kg/m3, 20.75 MPa) can withstand the 2075 meters water pressure and provide 550 kg/m3 buoyancy, which can givesome advice to the preparation of buoyancy material used in deepwater oil exploration.

Liquid Chromatography Quadrupole Time-Of-Flight Tandem Mass Spectrometry for Selective Determination of Usnic Acid and Application in Pharmacokinetic Study

Fang, Minfeng,Wang, Hui,Wu, Yang,Wang, Qilin,Zhao, Xinfeng,Zheng, Xiaohui,Wang, Shixiang,Zhao, Guifang Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

A rapid and sensitive method for determining usnic acid of Lethariella cladonioides in rat was established using high performance liquid chromatography (HPLC) quadrupole time-of-flight (QTOF) tandem mass (MS/MS). Rat plasma was pretreated by mixture of acetonitrile and chloroform to precipitate plasma proteins. Chromatographic separation was achieved on a column ($50{\times}2.1$ mm, $5{\mu}m$) with a mobile phase consisting of water (containing $5{\times}10^{-3}$ M ammonium formate, pH was adjusted to 3.0 with formic acid) and acetonitrile (20:80, v/v) at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via collision induced dissociation (CID) under negative ionization mode. The MS/MS transitions monitored were m/z 343.0448 ${\rightarrow}$ m/z 313.2017 for usnic acid and m/z 153.1024 ${\rightarrow}$ m/z 136.2136 for protocatechuic acid (internal standard). The linear range was calculated to be 2.0-160.0 ng/mL with a detection limit of 3.0 pg/mL. The inter- and intra-day accuracy and precision were within ${\pm}7.0%$. Pharmacokinetic study showed that the apartment of usnic acid in vivo confirmed to be a two compartment open model. The method was fully valid and will probably be an alternative for pharmacokinetic study of usnic acid.

Influence of Interface Structure on Dielectric Properties of Epoxy/Alumina Nanocomposites

Jinhong Yu,Genglin Wang,Ruimei Huo,Chao Wu,Xinfeng Wu,Pingkai Jiang 한국고분자학회 2012 Macromolecular Research Vol.20 No.8

Alumina (Al2O3) nanoparticles with three different interface structures have been selected as reinforcement fillers for epoxy nanocomposite, that is surface untreated Al2O3 nanoparticles, γ-aminopropyl-triethoxysilane modified Al2O3 nanoparticles (Al2O3-APS), and hyperbranched aromatic polyamide grafted Al2O3 nanoparticles (Al2O3-HBP). The interface structures of the Al2O3 nanoparticles were characterized by X-ray diffraction and atomic force micrographs. Our studies reported the influence of the interface structure of Al2O3 nanoparticles on the morphology and dielectric properties of epoxy nanocomposites. It was found that the incorporation of the Al2O3-APS and Al2O3-HBP nanoparticles not only improved the dispersion of the nanoparticles in the epoxy matrix, but also enhanced the glass transition temperatures (Tgs) and largely influenced the dielectric properties of the epoxy nanocomposites as compared with the nanocomposites filled with the surface untreated Al2O3 nanoparticles. The improvement of Tgs, volume resistivity, dielectric strength, and the reduction of dielectric loss could be attributed to the good dispersion and special interface structure of the Al2O3 nanoparticles in the epoxy matrix.

Liquid Chromatography Quadrupole Time-Of-Flight Tandem Mass Spectrometry for Selective Determination of Usnic Acid and Application in Pharmacokinetic Study

Minfeng Fang,Hui Wang,Yang Wu,Qilin Wang,Xinfeng Zhao,Xiao-Hui Zheng,Shixiang Wang,Guifang Zhao 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

A rapid and sensitive method for determining usnic acid of Lethariella cladonioides in rat was established using high performance liquid chromatography (HPLC) quadrupole time-of-flight (QTOF) tandem mass (MS/MS). Rat plasma was pretreated by mixture of acetonitrile and chloroform to precipitate plasma proteins. Chromatographic separation was achieved on a column (50 × 2.1 mm, 5 μm) with a mobile phase consisting of water (containing 5 × 10−3 M ammonium formate, pH was adjusted to 3.0 with formic acid) and acetonitrile (20:80, v/v) at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via collision induced dissociation (CID) under negative ionization mode. The MS/MS transitions monitored were m/z 343.0448 → m/z 313.2017 for usnic acid and m/z 153.1024 → m/z 136.2136 for protocatechuic acid (internal standard). The linear range was calculated to be 2.0-160.0 ng/mL with a detection limit of 3.0 pg/mL. The inter- and intra-day accuracy and precision were within ± 7.0%. Pharmacokinetic study showed that the apartment of usnic acid in vivo confirmed to be a two compartment open model. The method was fully valid and will probably be an alternative for pharmacokinetic study of usnic acid.

Chemical Composition, Antioxidant and Cytoprotective Activities of Lotus Receptacle

Weicheng Hu,Gongcheng Wang,Ting Shen,Yuning Wang,Boran Hu,Xinfeng Wang,Lei Wu,Pengxia Li,Lilian Ji 한국원예학회 2015 Horticulture, Environment, and Biotechnology Vol.56 No.5

The nutritional composition (ash, protein, fat, crude fiber, and carbohydrate) and antioxidant activity of lotus receptacles (LRs) were studied. The LRs contained 88.25% carbohydrates, 22.90% crude fiber, 5.79% crude ash, 0.77% crude protein content, and 5.19% crude lipid on a dry weight basis. The ethanolic extract of lotus receptacle (ELR) exerted strong scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, hydroxyl radical (•OH), superoxide anion (O2-), and hydrogen peroxide (H2O2), as well as high reducing power. ELR pretreatment effectively elevated cell viability and decreased malondialdehyde (MDA) levels in H2O2-treated RAW 264.7 cells. Additionally, ELR had high phenolic and flavonoid contents with values of 318.15 mg gallic acid equivalent/g and 239.06 mg rutin equivalent/g, respectively. Moreover, the bioactivity-guided study of ELR resulted in the isolation and identification of quercetin-3-O-β-D-glucopyranoside (QOG), a dietary flavonoid. QOG exhibited strong DPPH free radical scavenging activity, with an IC50 value of 24.26 μM; docking studies revealed that QOC formed one hydrogen bond with LYS263 in the active site, suggesting it is, in part, responsible for the free activity of LR.

Escherichia coli-Derived Outer Membrane Vesicles Deliver Galactose- 1-Phosphate Uridyltransferase and Yield Partial Protection against Actinobacillus pleuropneumoniae in Mice

( Keji Quan ),( Zhuang Zhu ),( Sanjie Cao ),( Fei Zhang ),( Chang Miao ),( Xintian Wen ),( Xiaobo Huang ),( Yiping Wen ),( Rui Wu ),( Qigui Yan ),( Yong Huang ),( Xiaoping Ma ),( Xinfeng Han ),( Qin Z 한국미생물 · 생명공학회 2018 Journal of microbiology and biotechnology Vol.28 No.12

In our previous studies, we have identified several in vivo-induced antigens and evaluated their potential as subunit vaccine candidates in a murine model, in which the recombinant protein GalT showed the most potent immunogenicity and immunoprotective efficacy against Actinobacillus pleuropneumoniae. To exploit a more efficient way of delivering GalT proteins, in this study, we employed the widely studied E. coli outer membrane vesicles (OMVs) as a platform to deliver GalT protein and performed the vaccine trial using the recombinant GalTOMVs in the murine model. Results revealed that GalT-OMVs could elicit a highly-specific, IgG antibody titer that was comparable with the adjuvant GalT group. Significantly higher lymphocyte proliferation and cytokines secretion levels were observed in the GalT-OMVs group. 87.5% and 50% of mice were protected from a lethal dose challenge using A. pleuropneumoniae in active or passive immunization, respectively. Histopathologic and immunohistochemical analyses showed remarkably reduced pathological changes and infiltration of neutrophils in the lungs of mice immunized with GalT-OMVs after the challenge. Taken together, these findings confirm that OMVs can be used as a platform to deliver GalT protein and enhance its immunogenicity to induce both humoral and cellular immune responses in mice.

Structural features and thermoelectric performance of chalcopyrite Cu(In, Ga)Te2 system by isoelectronic substitution

Deng Shuping,Jiang Xianyan,Zhang Ziye,Liu Junjie,Chen Lili,Qi Ning,Tang Xinfeng,Wu Yichu,Chen Zhiquan 한국물리학회 2021 Current Applied Physics Vol.26 No.-

In this paper, a series of CuIn1-xGaxTe2 samples were prepared by vacuum melting combined with the spark plasma sintering process based on the initial stoichiometric ratios of 1: 1-x: x: 2 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0). Crystal results indicate that all Cu(In, Ga)Te2 system samples are the chalcopyrite structure with space group I42d. Thermal analysis results show that all the samples have excellent reproducibility and thermal stability. EPMA data indicates that Ga tended to replace In site instead of Cu or Te. Meanwhile, the roomtemperature carrier concentration of all p-type samples varies from 0.30 × 1019 to 1.25 × 1019cm 3, since carrier mobility changes from 15.16 to 69.27 cm2 V 1 s 1. Ultimately, the significantly reduced total thermal conductivity is observed in the Ga-doped samples, and the maximum ZT value of 0.80 is obtained at 773 K for the CuIn0.8Ga0.2Te2 sample due to the lower thermal conductivity