JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 30
·期 13
·12113-12121
·
IF 2.195
Ruan Xuejun,Ren Xin,Zhou Wenting,Xu Xi,Wang Xin,Wang Manyu,Yan Ying,Yao Zheng,Shi Wen,Yu Wenqi
The effect of various proportions of SiO 2 and Cr 2 O 3 doping on the micro-characteristics and the electrical properties of the ZnO varistors were investigated. As the SiO 2 /Cr 2 O 3 ratio increased, the voltage gradient increased and then decreased, the nonlinear coefficient α increased, while the leakage current showed the opposite trend, meanwhile the residual voltage ratio was almost stable. When the SiO 2 /Cr 2 O 3 ratio was 1.7 mol% vs. 0.6 mol%, the ZnO varistors sintered at 1155 °C exhibited excellent comprehensive electrical properties with voltage gradient of 329.9 V/mm, nonlinear coefficient of 65.1, leakage current of 0 µA, residual voltage ratio of 1.663, and aging starting power of 0.72 W. The varistors were in good condition after being struck 18 times of 250 A square wave energy pulse impact, showing a great potential in the industrial application of power distribution systems.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 6
·1-11
·
IF 5.479
Huang Dong-Lan,Wang Jian,Cheng Fan,Ali Atif,Guo Hui-Shi,Ying Xiao,Si Li-Ping,Liu Hai-Yang
Graphene oxide (GO) was modified with the cobalt(II) and zinc(II) complexes (CoTFPP and ZnTFPP) of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin in order to improve the electrocatalytic activity of GO towards catechol (CC) and hydroquinone (HQ). It is found that the CoTFPP-modified GO on a glassy carbon electrode (GCE) displays the highest electrocatalytic activity. The response to CC (at 0.14 V vs. SCE) is linear in the 1–220 μM concentration range. The response to HQ (at 0.04 V vs. SCE) extends from 1 μM to 200 μM. The sensitivity and detection limits are 10.40 μA∙μM −1 ∙cm −2 and 0.17 μM for CC, and 8.40 μA∙μM −1 ∙cm −2 and 0.21 μM for HQ. Experimental results indicate that the Co(II) and Zn(II) ions in the porphyrins positively affect the electron transfer rate in the hybrid materials. The GCE modified with CoTFPP/GO was successfully applied to the simultaneous determination of CC and HQ in spiked samples of tap and lake water.
Schematic presentation of a voltammetric method for simultaneous determination of catechol (CC) and hydroquinone (HQ). It is based on the use of a cobalt (II) fluoroporphyrin (CoTFPP) functionalized graphene oxide (GO) hybrid.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 17
·11713-11725
·
IF 3.442
Zhang Xinfang,Shao Ziqiang,Zhou Yi,Wei Jie,He Weidong,Wang Shuo,Dai Xiaofu,Ren Jiaying
Because of irreversible agglomeration in the dehydrating process, the wet storage and transport of cellulose nanofibres (CNF) are the serious issues that need to be resolved in the commercialization and application of CNF. In this study, silanized cellulose nanofibres (Si-CNF) were prepared by modifying CNF with phenyltrimethoxysilane (PTS). Moreover, a mixture of redispersed Si-CNF and mineral oil was treated by combining ultrasound and high-pressure homogenizer to prepare Pickering emulsions. Different ratios of CNF/PTS were prepared and redispersed, and their morphological characteristics, thermal performance, rheological properties, zeta potential, and size distribution were analysed to evaluate the changes occurring during modification. The results show that the obtained Si-CNF demonstrates excellent redispersibility in water. The viscosity of the redispersed product exhibits the best suspension stability with the particle distribution uniform at the nanoscale when the addition amount of PTS is 0.18 mmol/g. Rheological and dynamic light scattering results have shown that the Pickering emulsion maintains the best dispersion stability at a concentration of 0.02% and remains stable after 7 days of storage. PTS modified the hydrophobicity of the CNF and provided alternative routes for application of CNF and Pickering emulsions.
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JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 17
·11596-11603
·
IF 3.442
Shen Hongxia,Nan Ruihua,Jian Zengyun,Li Xiaojuan
Perovskite MAPbBr 3 (MA = CH 3 NH 3 + ) single crystals were grown via the anti-solvent vapor-assisted crystallization method. The crystal growth process was optimized by adjusting the solution concentration and diluting the anti-solvent. The maximum size of the obtained crystal was 9 × 9 × 3 mm 3 . It shows that the MAPbBr 3 single crystal is a cubic structure, the space group is Pm \( \bar{3} \) m , and the lattice constant is 0.59062 nm. Furthermore, its energy band gap is approximately 2.23 eV. The atomic force microscopy results demonstrated that the growth process of MAPbBr 3 single crystal followed the defect step growth mechanism, which was controlled by the screw dislocations within the crystal. Based on the curling growth of a screw dislocation on the crystal surface, a spiral step was formed. After the step was rotated around the entire mesa, a higher step was generated. Repeatedly, the step growth of screw dislocation within the crystal came into being. Besides, some small pits were also observed on (100) plane of the MAPbBr 3 crystal. These pits hindered the movement of steps and affected the lattice arrangement around them, causing the structural mismatch and more defects within the crystals.
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BIOMEDICAL MICRODEVICES
·
2019
·Vol. 21
·期 4
·1-11
·
IF 2.327
Qiu Renna,Li Jian,Sun Denghua,Li Hongjun,Qian Feng,Wang Lizhe
Postoperative peritoneal adhesions are one of the most common surgical complications. In this study, we developed a 20(S)-ginsenoside Rg3-loaded methoxy poly (ethylene glycol)-block-poly(L-lactide-co-glycolide) (mPEG- b -PLGA) electrospun membrane (PEM/Rg3) that could not only serve as a physical barrier, but also as a drug delivery system that releases 20(S)-ginsenoside Rg3 constantly to prevent postoperative peritoneal adhesions. The characteristics of PEM/Rg3, including scanning electron microscopy, water contact angle, and mechanical analyses, were assessed. Degradation and drug release assays of PEM/Rg3 were performed. The anti-adhesion efficacy of PEM/Rg3 was evaluated in an abdomen-cecum mouse model. The adhesion scores, adhesion areas, hematoxylin and eosin (H&E) staining, immunofluorescence, and western blotting were assessed. The 20(S)-ginsenoside Rg3 loaded mPEG- b -PLGA electrospun fibers were successfully fabricated. The fibers were smooth, with no obvious drug crystals. PEM/Rg3 membranes were biodegradable and could be degraded gradually to release 20(S)-Ginsenoside Rg3 constantly from the membranes. The animal study showed that PEM/Rg3 exhibited an excellent adhesion prevention ability when compared with the control group, the PEM group, and polylactic acid (PLA) commercial membrane (Surgiwrap™) group. Immunofluorescence and western blotting studies showed that PEM/Rg3 inhibited the expressions of interleukin 1 (IL-1), interleukin 6 (IL-6), and reactive oxygen species modulator-1 (ROMO1). The 20(S)-ginsenoside Rg3-loaded mPEG- b -PLGA electrospun membranes exhibited satisfactory anti-adhesion efficacy by inhibiting inflammatory responses and oxidative stress. This composite represents a promising strategy to prevent postoperative peritoneal adhesions.
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高影响因子
CHROMATOGRAPHIA
·
2019
·Vol. 82
·期 9
·1345-1354
·
IF 1.552
Pang Xiaomin,Bai Ligai,Wang Zijun,Yang Huijun,Liu Haiyan,Yan Hongyuan
A 5-cm-long polymer-based chromatographic monolith was fabricated and used as the stationary phase for high-performance liquid chromatography to quantitatively determine six aroma compounds in edible spices, namely, anethole from star anise, trans -cinnamaldehyde from cinnamon, hydroxy-alpha-sanshool from zanthoxylum, as well as 6-gingerol, 8-gingerol, and 10-gingerol from ginger. The prepared monolith was characterized using scanning electron microscopy, nitrogen adsorption–desorption method, and mercury intrusion porosimetry, respectively, indicating the relative uniform porous structure of the monolithic material. The quantitatively analytical method using the homemade monolithic column was validated, and the values of the relative standard deviation for precision were in the ranges of 0.27–8.90% for intra-day and 0.93–8.28% for inter-day measurements. The values of accuracy, expressed by spiked recovery, were all within the range of 92.02–118.59%. Furthermore, real species obtained from different habitats were detected using the present method. All of the results indicate that the present method is a simple, time-saving, inexpensive, and efficient method for quantitatively analyzing aroma components from edible spices, and exhibits good specificity and durability.
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Nanoscale Research Letters
·
2019
·Vol. 14
·期 1
·1-10
·
IF 3.159
Tian Yefei,Lei Miao
Photothermal therapy (PTT) that utilizes phSUPPotothermal conversion agents (PTC) to ablate tumor under NIR light irradiation has attracted increasing attention due to its excellent therapeutic efficacy and improved target selectivity. Herein, a novel core-shell nanoparticle based on disulfide-crosslinked poly(methacrylic acid) (PMAA) layer coated polydopamine (PDA) particle has been successfully synthesized by precipitation polymerization. For these PDA@PMAA composite nanoparticles, PDA core exhibits high photothermal efficacy, meanwhile, the redox-labile PMAA shell serves as carriers to encapsulate anticancer drugs and selectively release them. Due to the characteristic of the disulfide bond, PMAA shell occurs at selective degradation as well as controlled drug release upon entering cancer cells. Moreover, the DOX-loaded PDA@PMAA nanoparticles demonstrated a synergistic effect, which shows a significantly improved inhibition effect against cancer cells by the combination of photothermal therapy and traditional chemotherapy with low drug dosage and short laser irradiation in an in vitro study.
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高影响因子
NAUNYN-SCHMIEDEBERGS ARCHIVES OF PHARMACOLOGY
·
2019
·Vol. 393
·期 1
·57-65
·
IF 2.058
Zhai Jiajia,Li Zeping,Zhang Huifeng,Ma Louyan,Ma Zhengquan,Zhang Yi,Zou Jian,Li Mo,Ma Li,Li Xiaomiao
The present study has been designed and carried out to evaluate the potential of coptisine on diabetic nephropathy. Diabetes was induced in SD rats through one single intraperitoneal injection of streptozotocin (65 mg/kg) method, and then diabetic rats were orally administered with 25 mg/kg/day coptisine or 50 mg/kg/day coptisine for 8 weeks. Severe impairment of renal function in rats with diabetes was observed as indicated by increased urine protein excretion, kidney hypertrophy index, serum creatinine level, and blood urea nitrogen level. Oxidative stress damage was observed as indicated by increased levels of reactive oxygen species, malondialdehyde, and decreased levels of glutathione, superoxide dismutase, and catalase. However, these alterations in kidneys of rats with diabetes were alleviated by administration of coptisine. Furthermore, the expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2) and its targeted antioxidative genes heme oxygenase 1 and NADPH quinone oxidoreductase 1 in the diabetic kidneys were significantly increased after coptisine treatment. These results suggested that coptisine ameliorated oxidative renal injury in diabetic rats, and the possible mechanisms for the renoprotective effects of coptisine may be related to activation of the Nrf2 signaling pathway.
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高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 8
·1-10
·
IF 5.479
Zhou Yunlei,Jiang Wenjing,Wu Hanwen,Liu Fei,Yin Huanshun,Lu Nan,Ai Shiyun
A nanocomposite was prepared from β-cyclodextrin (β-CD) functionalized graphene oxide and magnetic nanoparticles (GO/Fe 3 O 4 /β-CD). In parallel, a polyamidoamine dendrimer conjugated to avidinylated alkaline phosphatase (PAMAM-avidin-ALP) was prepared and exploited as a signal amplification unit in a voltammetric immunoassay for 5-methylcytosine (5mC) in genomic DNA. The GO/Fe3O4/β-CD as a substrate material exhibited good solubility, electrical conductivity and large surface. This is beneficial for the further modification of antibodies (Ab) by host-guest interaction and amide bonds. By taking advantage of three-dimensional structure to capture avidin-ALP by amide linkages, PAMAM was used as a catalytic signal amplification element in this assay. Under the optimized condition and at a typical working potential of 0.94 V, the response to 5mC is linear in the 0.01–50 nM concentration range with a detection limit of 3.2 pM (at S/ N = 3). The method is stable, selective and reproducible. It was applied to the determination of 5mC in genomic DNA of human tissue.
An electrochemical immunoassay was constructed for 5-methylcytosine detection based on nanocomposite of graphene oxide, magnetite nanoparticles and β-cyclodextrin, and enzymatic signal amplification.
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MOLECULAR IMAGING AND BIOLOGY
·
2019
·Vol. 22
·期 2
·265-273
·
IF 3.341
Zhao Chao,Liu Chunyi,Tang Jie,Xu Yingjiao,Xie Minhao,Chen Zhengping
Purpose The aim of this study was to optimize the radiolabeling method of [ 18 F]fluoropropyl-(+)-dihydrotetrabenazine ([ 18 F]FP-(+)-DTBZ) to fulfill the demand of preclinical and clinical application. Procedures Optimized labeling conditions were performed by altering the molar ratio of precursor to base (P/B), base species, solvents, reaction temperature, reaction time, and precursor concentration through manual radiosynthesis of [ 18 F]FP-(+)-DTBZ. The conditions with the highest radiochemical yield (RCY) were applied to automated radiosynthesis, and the crude product was purified with a Sep-Pak Plus C18 cartridge. Quality control and stability of [ 18 F]FP-(+)-DTBZ were carried out by HPLC. In vitro cellular uptake and blocking assays were conducted in human neuroblastoma cell line SH-SY5Y. In vivo imaging with small animal positron emission tomography (microPET) was performed with Sprague–Dawley rats. Results Under the optimized conditions (P/K 2 CO 3 = 1:8, heating at 120 °C for 3 min in dimethyl sulfoxide), an RCY of 88.7 % was obtained with 1.0 mg precursor. The optimized reaction conditions were successfully applied to an automated module and gave a high activity yield (AY) of 30–55 % in about 40 min with a > 99.0 % radiochemical purity (RCP) and a > 44.4 GBq/μmol molar activity ( A m ). Stability test displayed that the RCP retained > 98.0 % in 8 h in saline and in phosphate buffer saline (PBS, pH 7.4). In vitro cellular uptake assay showed accumulation of [ 18 F]FP-(+)-DTBZ in SH-SY5Y cells, which could be significantly inhibited by vesicular monoamine transporter 2 (VMAT2) inhibitor DTBZ. MicroPET images of rat brain displayed that the striatum showed the highest uptake with a standardized uptake value (SUV) of 3.91 ± 0.30 at ~ 70 min. Co-injection with DTBZ (1.0 mg/kg) resulted in a 75 % decrease of the striatal SUV, confirming the specificity of [ 18 F]FP-(+)-DTBZ to VMAT2. Conclusions We obtained an optimized radiolabeling method of [ 18 F]FP-(+)-DTBZ and successfully applied it to a commercial available module. The automated synthesis gave a high AY and RCP of [ 18 F]FP-(+)-DTBZ with high and specific binding to VMAT2, facilitating its routine application for VMAT2 tracing.
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高影响因子
CHEMICAL PAPERS
·
2019
·Vol. 74
·期 4
·1289-1299
·
IF 1.246
Zhao Chen-Hao,Peng Bo-Jun,Hu Zhi-Biao
Peanut shell-derived porous carbon has been prepared by the KOH-assisted hydrothermal treatment and subsequent carbonization route. The influences of KOH concentrations on structure of resulting carbon are clearly studied. At a KOH concentration of 5 M, the obtained porous carbon, possessing inner micropores and surface macropores, has a specific surface area of 827.7 m 2 /g and moderate porous size. The amorphous Se is uniformly encapsulated into its microporous structure to form hierarchical porous carbon/selenium composite. As the cathode material of Li ion battery, this composite delivers an initial discharge capacity of 590.6 mA h/g with Coulombic efficiency of 71.6% at 0.2 C, and a high capacity retention ratio of 83.3% can be reached after 500 cycles at 2 C. Even at a high rate of 4 C, this composite still presents a discharge capacity of 405.8 mA h/g. By comparison, these improved electrochemical performances may be attributed to the hierarchical porous feature, moderate porous size and effective encapsulation of selenium.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 55
·期 4
·1854-1864
·
IF 3.442
Zhang Zhizhong,Li Liang,An Duo,Li Hanxue,Zhang Xinghua
Novel triazine-based covalent organic polycalix[4]arenes, CalCOPs, were synthesized via the copolymerization of calix[4]arene derivatives and 2,4,6-trichloro-1,3,5-triazine (TCT) or 2,4-dichloro-1,3,5-triazine (DCT). The resulting CalCOPs have permanent pores that can be regulated by the variation of the alkyl chain lengths of the calixarene backbones and the reaction sites. With the alkyl chain length at the low rim in calixarene units increasing from ethyl to butyl during the reaction, the Brunauer–Emmett–Teller surface areas decrease with surface areas of 280, 31.5, 18.4 and 1.6 m 2 g −1 obtained for CalCOP1, CalCOP2, CalCOP3 and CalCOP4, respectively. Among these CalCOPs, CalCOP1 shows ultrahigh absorption for iodine capture in a water solution with an uptake of up to 232 wt%. Furthermore, the adsorption and release efficiency of iodine were obtained by using the UV–Vis spectroscopy. In addition, these polymers can be recycled at least five times while maintaining high removal capacity, suggesting that CalCOPs are ideal absorbent materials for reversible iodine capture in the mitigation of environmental issues.
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