Analytical Methods
·
2020
·Vol. 12
·期 22
·2827-2834
·
IF 2.596
Kai Hu,Jiamin Cheng,Jinge Li,Shan Ye,Huaixia Yang,Yanju Liu,Jinming Kong
The sensitive detection of biomarker cytokeratin fragment antigen 21-1 (CYFRA21-1) is crucial for early diagnosis and screening of non-small cell lung cancer (NSCLC). In this work, an electrochemical biosensor based on Nafion-initiated eATRP has been built for ultrasensitive detection of CYFRA21-1 DNA for the first time. Specifically, peptide nucleic acid (PNA) probes are immobilized onto a gold electrode surface and then hybridized with target DNA to form PNA/DNA heteroduplexes for the subsequent attachment of Nafion by the identified carboxyl–Zr4+–phosphoric acid chemistry. Finally, polymer chains are obtained by linking the monomer of ferrocenylmethyl methacrylate to the PNA/MCH/DNA/Zr4+/Nafion probes via eATRP. Under optimized steady-state conditions, the sensor offers a wide current response for CYFRA21-1 DNA from 10−11 to 10−16 M with a detection limit of 6.42 × 10−17 M. The proposed method of using Nafion as the eATRP initiator exhibits high sensitivity, reproducibility and stability and is a promising strategy for early diagnosis of NSCLC.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Xiaohua Zhang,Ning Chang,Jie Zhang,Yuanyuan Zhou,Zhenxing Yue,Longtu Li
In the present work, a series of (1-x)Ba 0.6 Sr 0.4 La 4 Ti 4 O 15 -xCaTiO 3 (x = 0.02, 0.03, 0.05, 0.1 and 0.2, BSLT-CT) functional ceramics were synthesized via co-firing the mixtures of Ba 0.6 Sr 0.4 La 4 Ti 4 O 15 and CaTiO 3 powders. Crystal structure and microwave dielectric properties were investigated together thermally stimulated depolarization currents (TSDC). Scanning electron microscopy (SEM) would be explored. X-ray diffraction confirms that these compounds display a single hexagonal phase with perovskite structure and the diffraction peaks shift to high angles with increasing CaTiO 3 content. Raman spectra uncover O h symmetry deviation and distortions of oxygen octahedra. The variation of the CaTiO 3 addition has a direct impact on the dielectric properties of the (1-x)BSLT-xCT ceramics at microwave frequency. TSDC was conducted to acquire the defects associated with extrinsic microwave loss mechanism. The main type of defect in BSLT-CT is oxygen vacancy ( V O • • ), namely involving in-grain and across-grain relaxation. The increase of CaTiO 3 prompts the increase of oxygen vacancy concentration, which may induce microwave loss. At x = 0.2, the microwave dielectric properties of specimens are ε r = 47.1, Q × f = 41,200 GHz and τ f = −5.3 ppm/°C, respectively.
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POLYMER
·
2019
·
IF 3.771
Yuehong Pang,Nianci Yang,Xiaofang Shen,Yi Zhang,Liheng Feng
Urinary 1-hydroxypyrene (1-OHP), one of the metabolite of polycyclic aromatic hydrocarbons (PAHs), has been extensively applied as a biomarker of animals and human exposure to PAHs. Herein, we synthesized a novel conjugated polymer poly-8-methoxy-7-methyl-5-(10-anthracen-9-yl)quinolone (PMMAYQ) using Suzuki coupling reaction, and then fabricated a homogeneous PMMAYQ/grahene multilayer film via layer-by-layer self-assembly technique and applied for electrochemical sensing of 1-OHP. Under the optimal conditions, {PMMAYQ-Graphene} 16 modified glass carbon electrode exhibited excellent response for detection of 1-OHP. A linear range from 0.5 to 120 nM was obtained with a low detection limit of 0.07 nM (S/N = 3) and a sensitivity of 0.5539 μA/μM. The electrochemical sensor exhibited excellent stability, accepted repeatability, and good selectivity. The developed method was employed for determination of 1-OHP in human urine samples and recoveries in the range of 95.6%–107.1% were achieved.
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BIOSCIENCE REPORTS
·
2018
·Vol. 38
·期 2
·
IF 2.899
Wang Qian,He Yuan,Lu Rui,Wang Wen-Ming,Yang Ke-Wu,Fan Hai Ming,Jin Yi,Blackburn G. Michael
The New Delhi metallo-β-lactamase (NDM-1) is an important clinical target for antimicrobial research, but there are insufficient clinically useful inhibitors and the details of NDM-1 enzyme catalysis remain unclear. The aim of this work is to provide a thermodynamic profile of NDM-1 catalysed hydrolysis of β-lactams using an isothermal titration calorimetry (ITC) approach and to apply this new method to the identification of new low-molecular-weight dicarboxylic acid inhibitors. The results reveal that hydrolysis of penicillin G and imipenem by NDM-1 share the same thermodynamic features with a significant intrinsic enthalpy change and the release of one proton into solution, while NDM-1 hydrolysis of cefazolin exhibits a different mechanism with a smaller enthalpy change and the release of two protons. The inhibitory constants of four carboxylic acids are found to be in the micromolar range. The compounds pyridine-2,6-dicarboxylic acid and thiazolidine-2,4-dicarboxylic acid show the best inhibitory potency and are confirmed to inhibit NDM-1 using a clinical strain of Escherichia coli. The pyridine compound is further shown to restore the susceptibility of this E. coli strain to imipenem, at an inhibitor concentration of 400 μM, while the thiazoline compound also shows a synergistic effect with imipenem. These results provide valuable information to enrich current understanding on the catalytic mechanism of NDM-1 and to aid the future optimisation of β-lactamase inhibitors based on these scaffolds to tackle the problem of antibiotic resistance.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2018
·Vol. 18
·期 4
·2601-2608
·
IF 1.354
Lin Jinrui,Ni Xiuyuan
In this study, a photochemical polymerization using graphene oxide (GO) as an initiator generated a new composite film with poly(1-vinylimidazole) (PVI) covered the GO sheets. Atomic force microscopy and infrared spectroscopy revealed the uniform layering of the PVI on the sheets. An
ITO/GO–PVI/Cu device was fabricated from this synthesized film, and it exhibited a write-once-read-many-times (WORM) memory functionality with resistance switching under an applied voltage of −3.2 V. The ON/OFF current ratio of the device reached 106. An analysis of the current–voltage
characteristics of the device indicated that the ON-state charge transport followed Ohmic conduction with metallic behavior, while the OFF-state charge transport was dominated by a trap-limited space charge limited conduction.
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Nano Life
·
2015
·
IF 0
Qiong Yi,Ling Li,Lu Fan,Keke Sun,Lebao Mao,Keke Liang,Li Liu
The adsorption of three kinds of azo dyes from aqueous solution on HKUST-1/graphene oxide (GO) composite was studied in view of the removal efficiency, adsorption isotherm, and regenerate of the sorbent. HKUST-1/GO was found to be with higher dyes removal efficiency than HKUST-1. All the adsorption isotherms of azo dyes on HKUST-1/GO composite followed Freundlich isotherm. The adsorbed azo dyes on HKUST-1/GO could be eluted by acetone, so HKUST-1/GO can also be used for enrichment of azo dyes as adsorbent.
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CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
C. Shen,Y.J. Wang,J.H. Xu,G.S. Luo
Porous glass supported with titanium silicalite (TS-1) particles were successfully prepared and used for oxidative desulfurization (ODS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). Uniform-sized TS-1 particles were homogeneously dispersed on the surface of the porous glass beads. Effects of reaction duration, catalyst content, initial concentration, oxidant amount, and temperature on conversions were investigated. The prepared catalysts showed excellent catalytic performance. The optimal mole ratio of oxidant-to-DBT was 10 or 15. Complete conversion was obtained within 3 min at 343 K using catalyst with Ti content of 0.507 wt.%. Compared with other studies, the space–time yield was increased by one order of magnitude without any addition of solvent or metal nanoparticles. Experimental results and computer simulations revealed that the coordinated state of Ti species has a key role in the catalytic activity. Spent catalyst would be regenerated by heating at high temperature, no decrease was observed in catalytic activity after three cycles.
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JOURNAL OF NEUROCHEMISTRY
·
2015
·Vol. 134
·期 5
·904-914
·
IF 4.281
Zhuang Wu,Linlang Li,Long-Tai Zheng,Zhihong Xu,Lin Guo,Xuechu Zhen
Recent studies have shown that sigma-1 receptor orthodox agonists can inhibit neuroinflammation. SKF83959 (3-methyl-6-chloro-7,8-hydroxy-1-[3-methylphenyl]-2,3,4,5-tetrahydro-1H-3-benzazepine), an atypical dopamine receptor-1 agonist, has been recently identified as a potent allosteric modulator of sigma-1 receptor. Here, we investigated the anti-inflammatory effects of SKF83959 in lipopolysaccharide (LPS)-stimulated BV2 microglia. Our results indicated that SKF83959 significantly suppressed the expression/release of the pro-inflammatory mediators, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS), and inhibited the generation of reactive oxygen species. All of these responses were blocked by selective sigma-1 receptor antagonists (BD1047 or BD1063) and by ketoconazole (an inhibitor of enzyme cytochrome c 17 to inhibit the synthesis of endogenous dehydroepiandrosterone, DHEA). Additionally, we found that SKF83959 promoted the binding activity of DHEA with sigma-1 receptors, and enhanced the inhibitory effects of DHEA on LPS-induced microglia activation in a synergic manner. Furthermore, in a microglia-conditioned media system, SKF83959 inhibited the cytotoxicity of conditioned medium generated by LPS-activated microglia toward HT-22 neuroblastoma cells. Taken together, our study provides the first evidence that allosteric modulation of sigma-1 receptors by SKF83959 inhibits microglia-mediated inflammation. SKF83959 is a potent allosteric modulator of sigma-1 receptor. Our results indicated that SKF83959 enhanced the activity of endogenous dehydroepiandrosterone (DHEA) in a synergic manner, and inhibited the activation of BV2 microglia and the expression/release of the pro-inflammatory mediators, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS).
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CHINESE JOURNAL OF CATALYSIS
·
2015
·
IF 1.964
Xiaoming Zhang,Shengmei Lu,Mingmei Zhong,Yaopeng Zhao,Qihua Yang
Rh-PPh 3 -polymer@mesosilica composites were prepared by the polymerization of mixtures of divinylbenzene (DVB) and 4-vinyl-triphenylphosphine monomer in the nanopores of mesoporous silicas followed by coordination with Rh(acac)(CO) 2 (acac =acetylacetonate). These catalysts were characterized by XRD, N 2 sorption , TEM, FT-IR, and TG, and could efficiently catalyze the hydroformylation of 1-octene with higher activity than a pure polymer catalyst because of their high surface area and large pore volume, which were beneficial for the exposure of active sites and mass transport. Through the control of pore size and pore connectivity by using different mesoporous silica (MCM-41, SBA-15, and FDU-12), the activity and selectivity can be controlled. Rh-PPh 3 -polymer@FDU-12 with a cage-like mesostrucuture showed lower activity but slightly higher selectivity than the catalyst with a 2-D hexagonal mesostructure (Rh-PPh 3 -polymer@SBA-15 or Rh-PPh 3 -polymer@MCM-41). By varying the polymer content in the nanopores of the mesosilica, the activity and selectivity (92%–96%) can also be tuned. The solid composite catalyst can be recycled without loss of activity, but a decrease in selectivity was observed.
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JOURNAL OF MOLECULAR LIQUIDS
·
2015
·
IF 2.515
Airong Xu,Yajuan Zhang,Zhiyong Li,Jianji Wang
In the present work, seven 1-allyl-3-methylimizodalium carboxylate ionic liquids (ILs), including 1-allyl-3-methylimizodalium formate [Amim][HCOO], acetate [Amim][CH 3 COO], propionate [Amim][CH 3 CH 2 COO], butyrate [Amim][CH 3 (CH 2 ) 2 COO], glycollate [Amim][HOCH 2 COO], lactate [Amim][CH 3 CHOHCOO]) and benzoate [Amim][C 6 H 5 COO], have been synthesized and characterized. Density ( ρ ) and conductivity ( σ ) have been determined experimentally for these ILs at 298.15 K and atmospheric pressure. Then molar volume ( V m ), standard entropy ( S °), lattice energy ( U POT ) and molar conductivity ( Λ ) of the ILs have been derived from the density and conductivity data. Ionicity of the ILs has been estimated using the Walden plot. Meanwhile, how anionic structure of the ILs affects the volumetric and conductivity properties of 1-allyl-3-methylimidazolium carboxylate ILs has been discussed from the analysis of structure–property relationship.
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RSC Advances
·
2016
·Vol. 6
·期 113
·112445-112450
·
IF 3.289
Shanni Hong,Na Sun,Min Liu,Jine Wang,Renjun Pei
Galectin-1 is closely related with immune systems, and its overexpression may cause tumor metastasis. Owing to the better stability of antisense oligonucleotides than siRNA, we constructed a chimera of aptamer–antisense oligonucleotide (Apt–AS) for silencing the galectin-1 gene specifically. For studying the endocytosis pathways of Apt–AS by aptamer targeted delivery, we marked the 3′ terminus of Apt–AS with Alexa Flour 488 (Apt–AS488) so as to trace the pathways through the confocal microscope. Furthermore, Apt–AS was used to silence the expression of galectin-1. The results showed Apt–AS entered cells by a caveolae mediated endocytosis pathway, and the aptamer–antisense chimeras did not impair the antisense gene silencing efficiency. Moreover Apt–AS could improve the cellular uptake and selectively entered cells.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2017
·Vol. 43
·期 8
·4697-4710
·
IF 1.369
Sun Hao,Huang Xin,Wang Fang,Gu Zhenggui
Selective isomerization of 1-methylnaphthalene was carried out in a fixed-bed reactor over HBEA catalysts modified by acid and tetraethoxysilane treatments, respectively. Catalysts were characterized by X-ray diffraction, NH 3 temperature-programmed desorption, N 2 physisorption, inductively coupled plasma analysis, thermogravimetric analysis and Fourier transform infrared spectrometry after adsorption of pyridine. The results demonstrated that tetraethoxysilane treatment successfully passivated external active sites of the zeolite, but had little effect on the selectivity of isomerization reaction and catalytic stability. Dealumination of HBEA zeolite by treatment with oxalic and hydrochloric acids can lead to higher surface area and pore volume. Sufficiently strong Brönsted acidic sites were found to be responsible for the isomerization activity. Furthermore, a decrease in the number of Lewis acidic sites in acid-modified zeolites were advantageous to suppress the hydride transfer and subsequent side reactions that form coke, leading to higher 2-methylnaphthalene selectivity and longer catalytic life.
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