MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 7
·2289-2296
·
IF 4.831
Peng Juan,Feng Yun,Han Xiao-Xia,Gao Zuo-Ning
The authors describe an electrochemical sensor for simultaneous determination of bisphenol A (BPA) and hydroquinone (HQ). It is based on a carbon paste electrode doped with graphene and coated with poly(melamine) (PME/GR-CPE). The modified electrode exhibits excellent conductivity, electrooxidative activity and adsorptive capability. The differential pulse voltammetric peaks for HQ and BPA are separated by around 300 mV. Amperometric responses (at 0.5 V for HQ and 0.8 V for BPA; both vs. SCE) are linear for BPA in the 9.0 μM to 1.0 mM concentration range, and for HQ in the 7.0 μM to 1.0 mM concentration range. The respective detection limits are 10.5 nM and 74.0 nM. The sensor is reproducible, highly stable and sensitive. It was applied to the simultaneous determination of HQ and BPA in spiked tap water and waste water.
A sensor based on poly(melamine) coated on graphene-doped carbon paste electrode for simultaneous determination of bisphenol (BPA) and hydroquinone (HQ) was fabricated. The sensor possessed good reproducibility and high stability. The practical application of the sensor was demonstrated by the detection of HQ and BPA in tap water and wastewater samples.
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Particle and Fibre Toxicology
·
2016
·Vol. 13
·期 1
·1-13
·
IF 8.649
Guo Hua,Zhang Jing,Boudreau Mary,Meng Jie,Yin Jun-jie,Liu Jian,Xu Haiyan
Background Administration of silver nanoparticles (AgNPs) to mice could result in their distribution and accumulation in multiple organs, with notable prominence in liver, lungs, and kidneys. However, how AgNPs transport through blood vesicular system to reach the target organs is unclear, and the precise differences in the mechanisms of toxicity between AgNPs and silver ions still remain elusive. In the present research, the pathological changes on these target organs with a focus on inter-endothelial junction was investigated to gain a new insight of AgNPs toxicity by comparing the mechanisms of action of AgNPs and AgNO3.Methods We investigated the in vitro cytotoxicity of either citrated-coated AgNPs (10, 75, and 110 nm) or silver nitrate (AgNO3) following 24 h incubations (1–40 μg/mL) in the presence of primary human umbilical vein endothelial cells (HUVEC). Meanwhile, we detected the effects of AgNPs on intercellular conjunction and intracellular ROS by VE-cadherin staining and 2′, 7′-dichlorodihydrofluorescein diacetate (DCFH-DA) assay, respectively. To assess in vivo toxicity, we administered single or multiple intravenous injections (25 μg Ag for AgNPs and 2.5 μg Ag for AgNO3 per dose) to mice.Results In the in vitro study, the TEM observation showed that AgNPs were taken up by endothelial cells while AgNO3 was taken up little. Meanwhile AgNPs incubation induced the elevation of intracellular ROS and down-regulation of VE-cadherin between the endothelial cells and affected the cytoskeleton actin reorganization, which could be rescued by antioxidant N-acetylcysteine. In contrast, AgNO3 caused direct cell death when the concentration was higher than 20 μg/mL and without ROS induction at lower concentration. The release of AgNPs from leaking vessels induced peripheral inflammation in the liver, lungs, and kidneys, and the severity increased in proportion to the diameter of the AgNPs used.Conclusion It is AgNPs but not AgNO3 that were taken up by vascular endothelial cells and induced intracellular ROS elevated, which was closely related to disruption of the integrity of endothelial layer. The AgNPs-induced leakiness of endothelial cells could mediate the common peripheral inflammation in liver, kidney and lung through intravenous exposure.
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高影响因子
NEUROCHEMICAL RESEARCH
·
2016
·Vol. 41
·期 8
·2110-2118
·
IF 2.472
Zhu Mingming,Li Bingfei,Ma Xiao,Huang Cong,Wu Rui,Zhu Weiwei,Li Xiaoting,Liang Zhaofeng,Deng Feifei,Zhu Jianyun,Xie Wei,Yang Xue,Jiang Ye,Wang Shijia,Wu Jieshu,Geng Shanshan,Xie Chunfeng,Zhong Caiyun,Liu Haiyan
Aluminum (Al)-induced apoptosis is considered as the major cause of its neurotoxicity. Folic acid possesses neuroprotective function by preventing neural cell apoptosis. microRNAs (miRNAs) are important regulators of gene expression participating in cellular processes. As a key component of the miR-17-92 cluster, miR-19 is implicated in regulating apoptotic process, while its role in the neuroprotective effect of folic acid has not been investigated. The present study aimed to investigate the potential involvement and function of miR-19 in the protective action of folic acid against Al-induced neural cell apoptosis. Human SH-SY5Y cells were treated with Al-maltolate (Al-malt) in the presence or absence of folic acid. Results showed that Al-malt-induced apoptosis of SH-SY5Y cells was effectively prevented by folic acid. Al-malt suppressed the expression of miR-19a/19b, along with alterations of miR-19 related apoptotic proteins including PTEN, p-AKT, p53, Bax, Bcl-2, caspase 9 and caspase 3; and these effects were ameliorated by folic acid. miR-19 inhibitor alone induced apoptosis of SH-SY5Y cells. Combination treatment of folic acid and miR-19 inhibitor diminished the neuroprotective effect of folic acid. These findings demonstrated that folic acid protected neuronal cells against Al-malt-induced apoptosis by preventing the downregulation of miR-19 and modulation of miR-19 related downstream PTEN/AKT/p53 pathway.
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Science China-Chemistry
·
2016
·Vol. 59
·期 6
·770-775
·
IF 2.429
Wang Min,Li Fangzhen,Jiang Bingying,Xu Junqiang,Li Shuo,Xiang Yun,Yuan Ruo
The detection of protein/small molecule interactions plays important roles in drug discovery and protein/metabolite interactions in biology. In this work, by coupling the terminal protection of small molecule-linked ssDNA strategy with the unmodified and positively charged gold nanoparticle ((+)AuNP) nanoprobes, we have developed a sensitive and simple colorimetric sensor for the detection of folate receptor, a highly expressed protein in many kinds of malignant tumors. The target folate receptor binds the folate moieties of the folate-linked ssDNA through high affinity interactions and protects the protein-bound ssDNA from digestion by exonuclease I. The protected ssDNA thus adsorbs the ((+)AuNP) through electrostatic interactions, leading to a red-to-blue color change of the sensing solution for sensitive colorimetric detection of folate receptor at the sub-nanomolar level. Besides, this colorimetric sensor shows high selectivity toward folate receptor against other control proteins. The developed sensor avoids the modification/conjugation of the AuNP nanoprobes and the involvement of any expensive instruments for signal transduction in protein detection. Featured with these obvious advantages, the colorimetric sensor strategy demonstrated herein can be easily expanded for sensitive and convenient detection of various protein/small molecule interactions.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2016
·Vol. 181
·期 3
·972-985
·
IF 1.606
Wu Hua-Lei,Zhang Jian-Dong,Zhang Chao-Feng,Fan Xiao-Jun,Chang Hong-Hong,Wei Wen-Long
Four uncharacterized ω-transaminases (ωTAs) from Pseudomonas putida NBRC 14164 have been identified and cloned from the pool of fully sequenced genomes. The genes were functionally expressed in Escherichia coli BL21, and the enzymes were purified and characterized. Four TAs showed highly ( S )-selective ωTA activity and converted ( S )-α-methylbenzylamine and pyruvate to acetophenone and l -Ala. The maximum activity of cloned enzymes was in the pH range of 8.0– 8.5 (Pp36420), 8.5 –9. 5 (Pp21050), 9 .0– 9.5 (PpspuC), and 9.5 –1 0 . 5 (PpbauA), and the optimal temperatures were at 35 °C (Pp36420, Pp21050, and PpspuC) and 50 °C (PpbauA), respectively, with K
M of 161.3 mM (Pp21050), 136.7 mM (PpbauA), 398.5 mM (Pp36420), and 130.9 mM (PpspuC) and yielding a catalytic efficiency k
cat / K
M of 0.015, 0.003, 0.012, and 0.023 mM −1 s −1 . Several racemic amines and amino alcohols were resolved by the cloned ωTAs; perfect conversions (48–50 %) were obtained by at least one enzyme, and the residual substrates were left with 97–99 % ee. Kinetic resolution of racemic phenylglycinol was done with PpspuC in a 100-mL scale. Enaniomeric excess of ( S )-phenylglycinol reached 99 % with 45 % isolated yield. The high enantioselectivity and large substrate spectra of the cloned PpTAs showed an attractive potency for biotechnology application in production of chiral amines and amino alcohols.
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高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2016
·Vol. 42
·期 10
·7345-7358
·
IF 1.833
Wang Ruikun,Zhao Zhenghui,Liu Jianzhong,Lv Yukun,Ye Xuemin
Municipal wastewater sludge (hereafter, sludge) is economically recycled by mixing with coal to prepare slurry fuels, called coal sludge slurry (CSS). However, raw sludge needs to be pretreated before being prepared as CSS because of its high viscosity. Alkali and ultrasonication pretreatment can effectively disrupt the sludge flocs and improve slurrying performance. The alkali pretreatment method takes a long time but has a low cost, whereas the ultrasonication pretreatment method needs a high energy input but takes a short time. This study combined these two methods with complementary advantages to reduce the sludge pretreatment time and ultrasonication energy demand to improve the slurrying performance for sludge. Results showed that, compared with only alkali and only ultrasonication, the combined alkali and ultrasonication pretreatment method had stronger effects on reducing slurry viscosity. The characteristic viscosity η
c of CSS prepared by raw sludge was 1663.60 mPa s. It was reduced to 1033.44 and 1472.10 mPa s, respectively, after the sludge was only pretreated by NaOH and Ca(OH) 2 at a dosage of 10 % dry sludge (DS) for 2 h, while it was reduced to 1205.43 mPa s after the sludge was only pretreated by ultrasonication of 30 kJ/g DS. After combined pretreatment, η
c of CSS was reduced to 774.98 mPa s (NaOH of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS) and 1083.24 mPa s (Ca(OH) 2 of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS), respectively. Apparently, the combined method can effectively decrease the alkali dosage or the ultrasonication energy input.
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JOURNAL OF SOLUTION CHEMISTRY
·
2016
·Vol. 45
·期 5
·702-711
·
IF 1.256
Yang Ya,Jin Jing,Wang Jinshou,Shi Zhen,Zhang Shenghui
We have constructed the pseudoternary phase diagram of surfynol465 + n -butanol + cyclohexane + H 2 O with k
m = 2 (where k
m is the weight ratio of surfynol465 to n -butanol) by the water titration method. Electrical conductivity measurements were employed to investigate the microstructures of the single-phase region. In the oil/water microemulsion region, we have measured the hydrolysis reaction rate of 2-bromo-2-methylpropane near and far away from the critical point. It was found that the Arrhenius equation was valid for correlating experimental measurements far away from the critical point but a significant acceleration effect exists near the critical point, which is not consistent with thermodynamic interpretation of Griffiths and Wheeler.
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JOURNAL OF APPLIED ELECTROCHEMISTRY
·
2016
·Vol. 46
·期 6
·703-712
·
IF 2.223
Luo He-Ming,Chen Hui,Chen Yan-Zheng,Li Ping,Zhang Jian-Qiang,Zhao Xia
Abstract Porous carbon materials have been prepared by direct carbonization of potassium stearate in inert atmosphere without any further activation. The porous carbon materials exhibited a typical hierarchical pore size distribution, thereby rendering them the excellent supercapacitive performance. All electrochemical measurements were performed in a three-electrode system using 6 M KOH as the electrolyte. CK800 can deliver a high specific capacitance of 208 F g −1 (36.1 µF cm −2 ) at a current density of 0.5 A g −1 . As the current density increased up to 30 A g −1 , a high specific capacitance of 120 F g −1 (20.8 µF cm −2 ) still can be maintained. 90.86 % of the specific capacitance was retained even after 5000 charge/discharge cycles at a current density of 2 A g −1 . Graphical Abstract
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 6
·1909-1916
·
IF 4.831
Dai Shaoliang,Wu Shijia,Duan Nuo,Wang Zhouping
The authors describe a turn-on luminescence resonance energy transfer (LRET) method for the detection of the mycotoxin Ochratoxin A (OTA). It utilizes upconversion nanoparticles (UCNPs) of the type NaYF 4 : Yb, Er as the energy donor and gold nanorods (Au NRs) as the acceptor. Biotin-labeled OTA aptamers were bound to the surface of the avidin-functionalized UCNPs. The AuNRs, in turn, were modified with thiolated OTA aptamer cDNA via thiol chemistry. The emission band of the UCNPs under 980-nm laser excitation has a maximum peaking at 657 nm and overlaps the absorption band of the AuNRs which peaks at 660 nm. Quenching of luminescence occurs because the hybridization actions shorten the distance between UCNPs and AuNRs. If, however, OTA is added, the two kinds of particles separate again because of the high affinity between OTA and the OTA aptamer. As a result, luminescence is recovered. The calibration plot is linear in the 0.05 to 100 ng mL −1 OTA concentration range, and the limit of detection is 27 pg mL −1 . The method was successfully applied to the determination of OTA in beer.
The luminescence of aptamer-modified upconversion nanoparticles (avidin-UCNPs) is quenched by cDNA-modified gold nanorods (AuNRs) due to hybridization. In the presence of Ochratoxin A (OTA), however, the luminescence of the UCNPs recovers due to competitive binding of aptamer to OTA.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 24
·期 26
·21011-21023
·
IF 2.741
Liu Yunsong,Chen Jiajun,Wang Qingwei,Shi Lanxiang,Shi Yandan
Viscosity remedial technology, which uses a water-soluble polymer mixed with remedial fluids, has been introduced in recent years to improve the removal efficacy of perchloroethylene/tetrachloroethylene (PCE) by improving oxidant coverage (i.e. sweep efficiency). Xanthan gum and hydrolysed polyacrylamide (HPAM) are relatively stable with time and temperature and possess salt and oxidation resistance, indicating that they may be good flooding agents (the former is better than the latter in this work). In this work, we quantified the polymer directly improved oxidation of PCE during transport by using a two-dimensional flow tank. Using a low pore volume (≤3.0), the removal rate of the PCE increased with the polymer concentration before stabilizing at approximately 93.00 and 88.30% for xanthan and HPAM, respectively. In this work, over 80% of PCE was removed via less than 3.0 PV of the SDS solution, whereas complete removal (100%) was achieved with less than 3.0 PV of SDS foam. Furthermore, the new experimental discoveries demonstrate that xanthan is better than HPAM and SDS foam is a better remediation agent than the SDS solution for removing PCE.
(Reaction device, A - inlet device (pump 1#), B - 2D tank, C - outflow device (pump 2#), D - data recording and processing device, E - microscopic expression, E (a) - KMnO 4 flushing, E (b) - polymer solution flushing).
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Molecular & Cellular Toxicology
·
2017
·Vol. 13
·期 1
·59-64
·
IF 1.25
Chen Jiahong,Zhang Hang,Aniagu Stanley,Jiang Yan,Chen Tao
Trichloroethylene (TCE) had been shown to induce aberrant DNA methylation changes in mouse liver, which could be critical in the development of hepatocellular carcinoma. To understand the effect of methionine, a methyl donor, on TCE-induced mouse liver cancer, we exposed B6C3F1 mice to TCE in the presence or absence of methionine. We found that supplementation with methionine attenuated the TCE-induced hypo- and hyper-methylation status of Cdkn1a and Ihh in mouse liver, respectively. The TCE-induced mRNA expression changes of Cdkn1a, Ihh and Jun were also alleviated by methionine. However, methionine supplementation accelerated the TCE-induced mRNA over-expression of Mki67, and enhanced the TCE-induced mRNA down-regulation of Dnmt3a and Tet2. In summary, our results showed that methionine could attenuate at least part of the TCE-induced DNA methylation changes, but the additional gene expression changes induced by supplementary of methionine does not support the assumption that methionine could prevent TCE-induced liver carcinogenesis.
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Food Analytical Methods
·
2017
·Vol. 10
·期 7
·2566-2575
·
IF 2.038
Zhao Fengnian,She Yongxin,Zhang Chao,Wang Shanshan,Du Xinwei,Jin Fen,Jin Maojun,Shao Hua,Zheng Lufei,Wang Jing
A novel dummy molecularly imprinted polymer (MIP) for selective extraction and preconcentration of chloramphenicol (CAP) has been successfully developed by precipitation polymerization using thiamphenicol (TAP) as the dummy template, methacrylic (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and methanol as the porogen. The performances and recognition mechanism of MIPs and non-molecularly imprinted polymers (NIPs) has evaluated in terms of adsorption isotherms and adsorption kinetics. The results showed that the MIPs exhibited significant specific recognition toward CAP in water with a large adsorption capacity. To test the feasibility of MIP in real samples, the obtained MIPs were applied as the selective sorbents for the solid-phase extraction of CAP from milk samples. Under optimized conditions, a rapid, convenient, and efficient method for the determination of CAP in milk samples based on MISPE coupling with high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) was throughly established. The method showed excellent recoveries (96.04~108.68%) and precision (RSDs <7.97%, n = 5) for milk samples spiked at three concentration levels (2, 5, and 10 μg L −1 ). The results demonstrated that the CAP in milk samples could be separated and purified through molecularly imprinted solid-phased extraction (MISPE), and this method could solve the leakage of template by the employment of dummy template effectively.
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