INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2018
·Vol. 54
·期 5
·1720-1728
·
IF 2.383
Lukai Ma,Guoqin Liu,Weiwei Cheng,Xinqi Liu
Summary The formation of 4-hydroxy-hexenal (HHE) and 4-hydroxy-nonenal (HNE) in eight vegetable oils was investigated at 180 °C. HHE was only detectable in soybean (SBO), rapeseed (RO) and linseed oils (LO). HNE was measured in all tested oils, but was found mainly in corn (CO), sunflower (SO) and soybean oil (SBO). Oil-dependent formation of HHE/HNE was remarkably observed. Furthermore, different fatty acid methyl esters in tricaprylin, as model oil systems, were constructed to demonstrate their characteristic contribution to HHE/HNE formation. As expected, HHE and HNE originated from the oxidative degradation of methyl linolenate (MLN) and methyl linoleate (ML) respectively. Whereas low concentrations of MLN (<5.0%) and ML (<1.0%) produced no detectable HHE/HNE. The results suggested MLN/ML could induce both HHE/HNE formation and pro-oxidation at higher concentrations. Unexpectedly, methyl stearate and methyl oleate slightly promoted HHE/HNE formation, which might be attributed to free radical transfer mechanisms during thermal oxidation.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·Vol. 141
·期 14
·e55182
·
IF 2.7
Hao Zheng,Dirong Gong,Yuanyuan Pang,Chun Tian,Zhen Wang,Jingling Yan
A series of poly(ester imide) (PEsI) copolymers were synthesized using 3,3′,4,4′-biphenyltetracarboxylic dianhydride (4,4′-BPDA), 2,2′-bis(trifluoromethyl)benzidine (TFMB), and 4-aminophenyl-4′-aminobenzoate (APAB) as the monomers. Wide-angle x -ray diffraction results revealed that the average interchain distances of these polymers ranged from 4.6 to 5.7 Å, increasing with the increase of TFMB contents. PEsI-0.3 and PEsI-0.4 exhibited a glass transition temperature ( T g ) of 445 and 455°C, respectively, while no distinctive T g was observed for the PEsI copolymers when the APAB content was >50 mol%. The coefficients of thermal expansion (CTE) of these PEsI copolymers ranged from 3.8 to 24.2 ppm K −1 , increasing with the increase of TFMB contents. The PEsI copolymers exhibited a modulus of 5.7–7.8 GPa, a tensile strength of 282–332 MPa, and an elongation-at-break of 10.2%–23.3%. Furthermore, these copolymers exhibited a dielectric constant of 2.53–2.76, and a low dissipation factor ( D f ) of 0.0026–0.0032 at 10 GHz in dry state. Because of their excellent combined properties, these PEsI copolymers are promising candidates as dielectric substrate materials for the applications in next generation flexible printed circuit boards operating at high frequencies.
研究领域:
材料科学
·
高分子化学
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Yibo Zhang,Cheng Qian,Ruiping Shi,Songyang Li,Fengwei Shi,Jianglei Hu,Sara Khan,Xia Yang
Herein, the –COOH functionalized ordered mesoporous silica (OMS-C) was successfully synthesized using 3-phosphonopropionic acid as a functionalized reagent via one-pot co-condensation method. Then Cu 2+ ions were adsorbed by the –COOH groups present on the OMS surface. Finally, the composite material (MOF-199@OMS-C) functionalized by Metal-Organic Framework (MOF-199) was in-situ prepared through the Cu 2+ ions adsorbed by the OMS-C. The experimental results of N 2 adsorption–desorption, low-angle XRD, and TEM showed that MOF-199@OMS-C composites possessed an ordered 2D hexagonal mesoporous structure, high specific surface area and the formation of MOF-199 in the pore of OMS-C. Moreover, FT-IR, Raman, XPS, and TG analysis demonstrated the carboxylation on the surface of OMS, successful synthesis, and immobilization of MOF-199 within the pores of OMS-C through the –COOH of OMS, as well as the interaction between OMS-C and MOF-199. The MOF-199@OMS-C composites exhibited good catalytic activity in the reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The apparent kinetic constant of the reduction reaction of 4-NP was 0.26 min −1 under the optimum reaction condition. The MOF-199@OMS-C composites prevented the loss and structural damage of MOF-199, and its catalytic activity even remained stable after 4 cycles. In addition, the kinetic curves of reduction reaction of 4-NPs were consistent with first-order kinetics.
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COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY
·
2020
·
IF 2.897
Jiao Yang,Qingyi Huang,Huan Liu,Xiong Zhou,Zhuoquan Huang,Quansheng Peng,Chunhong Liu
Environmental endocrine disruptors 4-nonylphenol (NP) and 4-tert-octylphenol (OP) may cast huge harm to human health. We used a rat model to observe the influence of NP or/and OP exposure on anxiety-related behaviors and the underlying mechanisms. Eighty male Sprague-Dawley (SD) rats were randomly divided into 10 groups: control group (corn oil), NP groups [30, 90, 270 mg/kg], OP groups [40, 120, 360 mg/kg] and NO groups [(mixed with the corresponding NP, OP alone exposed low, medium and high dose according to the natural environment exists NP:OP = 4:1]. The rats were orally administered every other day for 30 days. The neurobehaviors of rats were evaluated by open-field test (OFT) and elevated plus-maze test (EPM), and the concentrations of 5-HT, monoamine oxidase (MAOA), serotonin transporter (SERT), vesicular monoamine transporter 2 (VAMT2), 5-hydroxytryptamine 1A (5-HT 1A ), 5-hydroxytryptamine 2A (5-HT 2A )，and 5-hydroxytryptamine 2C (5-HT 2C ) in the rat prefrontal cortex were analyzed by ELISA . OFT and EPM tests showed that NP or/and OP exposure induced anxiety-related behaviors in rats. 5-HT levels were significantly increased compared with the control group. The levels of MAOA, SERT, VAMT2, 5-HT 1A , 5-HT 2A, and 5-HT 2C in the prefrontal cortex reduced in different degrees by high-doses NP or/and OP exposure. In summary, NP or/and OP exposure might cause anxiety-related behaviors in rats through regulating neurotransmitter 5-HT levels by altering the expression of 5-HT decomposition enzyme MAOA, transporters SERT and VMAT2, and 5-HT receptors 5-HT 1A , 5-HT 2A, and 5-HT 2C .
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PubMed
高影响因子
JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY
·
2016
·Vol. 43
·期 5
·585-593
·
IF 2.745
Jin Li-Qun,Guo Dong-Jing,Li Zong-Tong,Liu Zhi-Qiang,Zheng Yu-Guo
In this paper, a simple and effective method using sodium metasilicate as precursor and amine as additive was first reported to immobilize recombinant nitrilase, for efficient production of 2-hydroxy-4-(methylthio) butanoic acid from 2-hydroxy-4-(methylthio) butanenitrile. High immobilization recovery of enzyme activity (above 90 %) was achieved. The immobilized enzyme displayed better thermal stability, pH stability and shelf life compared to free nitrilase. Moreover, it showed excellent reusability and could be recycled up to 16 batches without significant loss in activity. 200 mM 2-hydroxy-4-(methylthio) butanenitrile was completely converted by the immobilized enzyme within 30 min, and the accumulation amount of 2-hydroxy-4-(methylthio) butanoic acid reached 130 mmol/g of immobilized beads after 16 batches. These encouraging results demonstrated the efficiency of the new technology for nitrilase immobilization, which has great potential in preparation of 2-hydroxy-4-(methylthio) butanoic acid.
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PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2017
·
IF 3.034
Li Luo,Yuan Yang,Qiang Wang,Hai-pu Li,Zhou-fei Luo,Zhi-peng Qu,Zhao-guang Yang
The presence of endocrine disrupting chemicals such as 4- n -octylphenol, 4- n -nonylphenol and bisphenol A in environmental samples and artificial products may cause health problems for human and organisms. This developed method was efficient for monitoring of those tracing emerging contaminates and the Plackett-Burman factorial design introduced in extraction step was timesaving. Matrix effect was also considered to ensure proper quantitation. Good linearity (r 2 > 0.99), low Method Detection Limits (MDL) and Method Quantitation Limits (MQL) range from 0.18 to 0.54 ng/g and 0.60 to 1.80 ng/g were obtained. Three level spiking experiment (4, 10, 15 ng/g) showed recoveries range from 74% to 113% for 4- n -octylphenol and 4- n -nonylphenol with RSD range from 2% to 11%. The method was finally applied to the analysis of real fish samples taken from Hunan Province, China, offering a reliable and effective means for monitoring of trace emerging contaminates in fishes largely consumed by residents.
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FLUID PHASE EQUILIBRIA
·
2015
·
IF 2.2
Chunlin Li,Qinbo Wang,Binwei Shen,Zhenhua Xiong,Chuxiong Chen
The solubilities of 5,10,15,20-tetrakis(4-chlorophenyl) porphyrin (abbreviated in p -ClTPP) in ethanol + water solvent mixtures at (293.2–333.2) K and 5,10,15,20-tetrakis(4-chlorophenyl) porphyrin manganese(III) chloride (abbreviated in p -ClTPPMnCl) in ethanol + water solvent mixtures at (303.2–333.2) K were measured. The concentration of ethanol in term of mole fraction on the solubility was studied. It was found that the solubility of p -ClTPP in ethanol + water solvent mixtures increases with the increasing of temperature at constant solvent composition , and decreases with the decreasing mole fraction of ethanol at constant temperature. However, for p -ClTPPMnCl, the solubility increases with the increasing of temperature at the mole fraction of ethanol from (0.6102–0.8597), and decreases with the increasing of temperature at the mole fraction of ethanol from (0.9038–1.0000). The experimental data were correlated with the modified Apelblat equation, and the solubilities correlated by the model were in good agreement with experimental data. Thermodynamic parameters including dissolution enthalpy, dissolution entropy and dissolution Gibbs free energy were calculated with van’t Hoff equation.
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CELLULOSE
·
2024
·Vol. 31
·期 10
·6141-6153
·
IF 4.9
Song Jun,Wang Linfeng,Shan Jicheng,Li Chuanmeng,Wang Mengdie
Cellulose liquid crystal solutions have been extensively studied, and the methylene length of mesogenic units has a significant influence on the properties of cellulose liquid crystal solutions. In this study, 4-(ω-(methylimidazole)alkyloxy)-4’-(cyano)-biphenyl (CBP-n) with 4–7 methylene lengths were synthesized as mesogenic units to prepare cellulose side chain liquid crystal in 1-Allyl-3-methylimidazolium chloride (AMIMCl). And their liquid crystal properties were studied by differential scanning calorimetry (DSC), in-situ infrared spectrometer (IR), torque rheometer, and polarizing microscope (POM). The results showed that CBP-n with 4–7 methylene lengths were thermotropic liquid crystal, and the cellulose/CBP-n/AMIMCl solutions were lyotropic liquid crystal when the concentration of cellulose is 6wt% and the concentration of CBP-n with methylene length 4 and 6 is 3wt%. In-situ IR proved that the liquid crystal formation of cellulose/CBP-n/AMIMCl solution was caused by the hydrogen bonding formed between cellulose and CBP-n. And the solutions have a fewer entanglement number and lower viscosity than those of methylene length 5 and 7, indicating that the hydrogen bonding interaction between CBP-n with even methylene length and cellulose molecule is stronger than that of odd methylene length. This study provides a new approach to produce cellulose fibers using cellulose/CBP-n/AMIMCl as a new renewable resource.
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Nanoscale
·
2024
·
IF 5.8
Guo He,Dezhi Yang,Sizhe Tao,Liqing Yang,Dechao Guo,Jingbo Zheng,Ji Li,Jiangshan Chen,Dongge Ma
Perovskite photodetectors (PPDs) offer a promising solution with low cost and high responsivity, addressing the limitations of traditional inorganic photodetectors. However, there’s still room for improvement in terms of dark current and stability of air-processed PPDs. In this study, 4',4"-Tris(carbazl-9-yl)-triphenylamine (TCTA) is utilized as nucleation agent to enhance the quality of perovskite film. The synergistic effect of TCTA and moisture promotes rapid nucleation of PbI2-PbCl2, resulting in an increased nucleation rate and the elimination of pinholes in the film. By employing additive engineering, we obtain a PbI2-PbCl2 layer with high coverage, leading to a lower density of traps in the corresponding perovskite film. Consequently, the modified PPD exhibits a remarkable reduction in dark current density by over one order of magnitude, reaching 2.4×10-10 A cm-2 at -10 mV, along with a large linear dynamic range (LDR) of 183 dB. Furthermore, the resulting PPD demonstrates remarkable stability, retaining 90% of the initial external quantum efficiency (EQE) value even after continuous operation for over 3200 hours. Due to a fast response time in nanosecond range, the PPD can convert modulated light signals into electrical signals at a speed of 588 Kbit s-1, highlighting great potential in the field of optical communication.
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PubMed
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Peihang Shen,Zelong Liu,Yibo Zhang,Zelin Meng,Mingyang Song,Heming Zhao,Jianglei Hu,Fengwei Shi
Vinyl-functionalized SBA-15 was synthesised using a one-pot co-condensation method followed by carboxylation via nitric acid, with the intermediate product named SBA-15C. MIL-68 was then synthesised in-situ by adsorption of Al 3 + ions via carboxylate groups on SBA-15C to give the composite xMIL-68(Al)@SBA-15C. A series of characterizations were conducted by Fourier transform infrared spectroscopy, Brunner-Emmet-Teller measurements, X-ray diffraction, X-ray photoelectron spectroscopy, Scanning electron microscope, and Transmission Electron Microscope. xMIL-68(Al)@SBA-15C maintained robust catalytic performance in the NaBH 4 -mediated reduction of 4-nitrophenol to 4-aminophenol, with no significant decrease in activity after five cycles of reuse.
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高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Junlong Niu,Shuai Chen,Wenna Zhang,Wenwen Zhang,Keke Chai,Guo Ye,Danqin Li,Weiqiang Zhou,Xuemin Duan,Jingkun Xu
Nanowire poly (3,4-dihydro-2 H -thieno [3,4- b ] [1,4]dioxepin-3-yl)methanol (PProDTM) free-supporting films with conductivities around 1.92 S cm −1 were prepared using a template-free electropolymerization method. The structure, morphology, mechanical properties, and thermal stability of the PProDTM films were characterized by Fourier transform infrared spectroscopy, UV–vis spectroscopy, scanning electron microscopy, dynamic mechanical analysis and thermogravimetric analysis . Moreover, the capacitance performances of PProDTM films were investigated in aqueous and organic electrolytes (acetonitrile (ACN) and dichloromethane (DCM)). In 0.1 M H 2 SO 4 , a symmetrical supercapacitor based on PProDTM exhibited specific capacitance of 89.2 F g −1 at a current density of 1.0 A g −1 , an energy density of 3.1 Wh kg −1 at power density of 0.5 kW kg −1 and the cycling capacitance retention was 74.8% after 5000 cycles. As the scan rate and current density increased, the specific capacitance of PProDTM films clearly decreased in DCM, but no obvious changes occurred in water and ACN. In ACN containing 0.1 M Bu 4 NBF 4 , a symmetrical supercapacitor based on PProDTM exhibited specific capacitance of 99.6 F g −1 at a current density of 1.0 A g −1 , an energy density of 3.5 Wh kg −1 at power density of 0.5 kW kg −1 and the cycling capacitance retention was 82.2% after 5000 cycles. These results imply that our flexible free-supporting PProDTM films are promising for future use in supercapacitors .
研究领域:
材料科学
·
电化学
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JOURNAL OF FLUORESCENCE
·
2011
·Vol. 22
·期 2
·729-736
·
IF 1.966
Li Yan-Yan,Yan Bing,Guo Lei
In this paper, the organic ligands TTA and TAA are grafted onto the coupling agent to achieve the organic precursors (TTA-Si, TAA-Si) as first ligand and the organic 4-(4-nitrostyryl)pyridine (Nspy) is synthesized as the second ligand. Both of them are coordinated to the rare ions with the carbonyl group and nitrogen atom respectively. After the hydrolysis and copolycondensation between the teraethoxysilane (TEOS) and the ternary rare earth organic complex via the sol–gel process, the chemical bonded hybrid materials are constructed and characterized in detail. The obtained hybrid materials present superior thermal stabilities and regular and homogenous square blocks microstructure. Among the hybrids Eu(TTA-Si) 3 Nspy shows a more strong characteristic emission and longer lifetime than the hybrids Eu(TAA-Si) 3 Nspy, while hybrids Tb(TAA-Si) 3 Nspy exhibits the stronger characteristic emission and longer lifetime than the hybrids Tb(TTA-Si) 3 Nspy. For Sm 3+ hybrid materials, the photoluminescence of Sm(TAA-Si) 3 Nspy is too weak to find in the characteristic emission spectra, meanwhile, Sm(TTA-Si) 3 Nspy has the excellent luminescent intensity.
研究领域:
材料科学
·
光物理学
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高影响因子
危险品化学品经营许可证（带存储）