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Sorina Motoc, Florica Manea, Adriana Iacob, Alberto Martinez-Joaristi, Jorge Gascon, Aniela Pop, Joop Schoonman
In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP) and diclofenac (DCF) in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF) electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV) was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA) and multiple-pulsed amperometry (MPA)...
October 17, 2016: Sensors
Jungmin Seo, Jee Hye Wee, Jeong Hoan Park, Pona Park, Jeong-Whun Kim, Sung June Kim
OBJECTIVE: A novel nerve cuff electrode with embedded magnets was fabricated and developed. In this study, a pair of magnets was fully embedded and encapsulated in a liquid crystal polymer (LCP) substrate to utilize magnetic force in order to replace the conventional installing techniques of cuff electrodes. In vitro and in vivo experiments were conducted to evaluate the feasibility of the magnet-embedded nerve cuff electrode (MENCE). Lastly, several issues pertaining to the MENCE such as the cuff-to-nerve diameter ratio, the force of the magnets, and possible concerns were discussed in the discussion section...
October 20, 2016: Journal of Neural Engineering
Yang Yu, Igor Petrik, Kelly N Chacón, Parisa Hosseinzadeh, Honghui Chen, Ninian J Blackburn, Yi Lu
Type 1 copper (T1Cu) proteins are electron transfer (ET) proteins involved in many important biological processes. While the effects of changing primary and secondary coordination spheres in the T1Cu ET function have been extensively studied, no report has explored the effect of the overall protein structural perturbation on active site configuration or reduction potential of the protein, even though the protein scaffold has been proposed to play a critical role in enforcing the entatic or "rack-induced" state for ET functions...
October 19, 2016: Protein Science: a Publication of the Protein Society
Nahid Shahabadi, Mehdi Pourfoulad, Neda Hosseinpour Moghadam
DNA-binding properties of an antiviral drug, valganciclovir (valcyte) was studied by using emission, absorption, circular dichroism, viscosity, differential pulse voltammetry, fluorescence techniques, and computational studies. The drug bound to calf thymus DNA (ct-DNA) in a groove-binding mode. The calculated binding constant of UV-vis, Ka, is comparable to groove-binding drugs. Competitive fluorimetric studies with Hoechst 33258 showed that valcyte could displace the DNA-bound Hoechst 33258. The drug could not displace intercalated methylene blue from DNA double helix...
October 19, 2016: Nucleosides, Nucleotides & Nucleic Acids
Minglun Cheng, Mei Wang, Dehua Zheng, Licheng Sun
Three biomimetic models of the [FeFe]-hydrogenase active site, namely diiron dithiolates of [(μ-edt){Fe(CO)3}{Fe(CO)(κ(2)-PNP)}] (1, edt = ethane-1,2-dithiolate, PNP = Ph2PCH2N(nPr)CH2PPh2), [(μ-bdtMe){Fe(CO)3}{Fe(CO)(κ(2)-PNP)}] (2, bdtMe = 4-methylbenzene-1,2-dithiolate), and [(μ-adtBn){Fe(CO)3}{Fe(CO)(κ(2)-PNP)}] (3, adtBn = N-benzyl-2-azapropane-1,3-dithiolate), were prepared and structurally characterized. These complexes feature the same PNP ligand but different S-to-S bridges. Influence of the S-to-S bridge on the electrochemical properties and chemical oxidation reactivity of 1-3 was studied by cyclic voltammetry and by in situ IR spectroscopy...
October 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Ruta Grinyte, Javier Barroso, Marco Möller, Laura Saa, Valeri Pavlov
Electrochemical detection strategies employing semiconductor quantum dots (QDs) open up new opportunities for highly sensitive detection of biological targets. We designed new a assay based on microbead linked enzymatic generation of CdS QDs (Microbead QD-ELISA) and employed it in optical and electrochemical affinity assays for the cancer biomarker superoxide dismutase 2 (SOD2). Biotinylated antibodies against SOD2 were immobilized on the surface of polyvinyl chloride microbeads bearing streptavidin. In order to prevent any non specific adsorption the microbeads were further blocked with bovine serum albumin...
October 18, 2016: ACS Applied Materials & Interfaces
Omid Sadeghi, Clément Falaise, Pedro I Molina, Ryan Hufschmid, Charles F Campana, Bruce C Noll, Nigel D Browning, May Nyman
The iron Keggin ion is identified as a structural building block in both magnetite and ferrihydrite, two important iron oxide phases in nature and in technology. Discrete molecular forms of the iron Keggin ion that can be both manipulated in water and chemically converted to the related metal oxides are important for understanding growth mechanisms, in particular, nonclassical nucleation in which cluster building units are preserved in the aggregation and condensation processes. Here we describe two iron Keggin ion structures, formulated as [Bi6FeO4Fe12O12(OH)12(CF3COO)10(H2O)2](3+) (Kegg-1) and [Bi6FeO4Fe12O12(OH)12(CF3COO)12](1+) (Kegg-2)...
October 18, 2016: Inorganic Chemistry
Michael P Saddoris
Repeated self-administration of cocaine is associated with impairments in motivated behaviors as well as alterations in both dopamine (DA) release and neural signaling within the nucleus accumbens (NAc). These impairments are present even after several weeks of abstinence from drug taking, suggesting that the self-administration experience induces long-lasting neuroplastic alterations in the mesolimbic DA circuit. To understand these changes at the terminal level, rats were allowed to self-administer either cocaine intravenously (∼1 mg/kg per infusion) or water to a receptacle (control) in 2-h sessions over 14 days, followed by 30 days of enforced abstinence...
September 2016: ENeuro
Guang-Yao Zhang, Yu-Hong Zhuang, Dan Shan, Guo-Fang Su, Serge Cosnier, Xueji Zhang
A simple and rapid photoelectrochemical (PEC) sensor is developed for the label-free detection of a phosphoprotein (α-casein) based on a zirconium based porphyrinic metal-organic framework (MOF), PCN-222, which exhibits an enhanced photocurrent response towards dopamine under the O2-saturated aqueous media. In this work, in terms of PEC measurements and cyclic voltammetry, the PEC behaviors of PCN-222 in aqueous media were thoroughly investigated for the first time. Additionally, in the virtue of the steric hindrance effect from the coordination of the phosphate groups and inorganic Zr-O clusters as binding sites in PCN-222, this biosensor shows high sensitivity for detecting α-casein and the limit of detection (LOD) is estimated to be 0...
October 18, 2016: Analytical Chemistry
Carlos A Teixeira, Gabriela Furlan Giordano, Maisa B Beltrame, Luis Carlos Silveira Vieira, Angelo Luiz Gobbi, Renato Sousa Lima
The contamination, passivation, or fouling of the detection electrodes is a serious problem undermining the analytical performance of electroanalytical devices. The methods to regenerate the electrochemical activity of the solid electrodes involve mechanical, physical, or chemical surface treatments that usually add operational time, complexity, chemicals, and further instrumental re-quirements to the analysis. In this paper, we describe for the first time a reproducible method for renewing solid electrodes when-ever their morphology or composition are non-specifically changed without any surface treatment...
October 17, 2016: Analytical Chemistry
Christopher Batchelor-McAuley, Christopher A Little, Stanislav V Sokolov, Enno Kätelhön, Giorgia Zampardi, Richard G Compton
The lipid soluble fluorophore Nile Red (9-diethylamino-5-benzo[α]phenoxazinone) is used to fluorescently and electrochemically label an organic-in-water emulsion, where the organic phase is an ionic liquid [P6,6,6,14][FAP]/toluene mixture. The optical detection of the individual droplets is enabled facilitating the in-situ tracking and sizing of the suspended particles (average diameter = 530 nm, interquartile range = 180 nm). Through the use of a combined thin-layer optical/electrochemical cell, the irreversible accumulation of the droplets at an optically opaque carbon fibre electrode (diameter ~ 7...
October 17, 2016: Analytical Chemistry
Shuguang Chen, Hailang Jia, Mengxi Zheng, Kang Shen, Hegen Zheng
Herein we prepare four novel D-π-A dyes based on triphenylamine (ZHG1, ZHG2, ZHG3 and ZHG4) by modifying the π-bridges. Compared with ZHG1, the power conversion efficiency (PCE) of ZHG2 is improved to 6.1% after the introduction of ethynyl. But further extension of the conjugation of the π-bridges by introducing the chromophore 4,8-bis(n-octyloxy)-benzo[1,2-b:4,5-b']dithiophene (BDT) into ZHG3 conversely decreases the PCE to 4.6%. Improving the coplanarity by replacing cyclobenzene with thiophene in ZHG4 after introducing BDT further decreases the PCE of ZHG4 to 4...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Andrea Buffa, Yigal Erel, Daniel Mandler
A flow-through electrode made of a carbon nanotubes (CNT) film deposited on a polytetrafluoroethylene (PTFE) membrane was assembled and employed for the determination of low concentration of copper as a model system by linear sweep anodic stripping voltammetry (LSASV). CNT films with areal mass ranging from 0.12 to 0.72 mg cm-2 were characterized by measurement of sheet resistance, water permeation flux and capacitance. Moreover, CNT with two different sizes and PTFE membrane with two different pore diameters (0...
October 17, 2016: Analytical Chemistry
Amit Chakraborty, Joydeb Goura, Prasenjit Bag, Arun Kumar Bar, Jean-Pascal Sutter, Vadapalli Chandrasekhar
Utilizing a new ferrocene-based compartmental ligand, H4L (1), a series of novel heterometallic complexes [{LZn(μ-OAc)Dy}4(μ4-H2O)] (2), [{LZn(μ-OAc)Tb}4(μ4-H2O)] (3), [{LZn(μ-OAc)Ho}4(μ4-H2O)] (4), [L = Fe[(C5H4){-C(Me)[double bond, length as m-dash]N-N[double bond, length as m-dash]C6H3-(o-O)(m-O)}]2] were synthesized and characterized. 2 and 3 crystallize in the monoclinic crystal system in the I2/m space group, whereas 4 crystallizes in the tetragonal crystal system in the I4/m space group. The tetra deprotonated ligand L(4-) has two distinct coordination compartments: one pocket (2N, 2O) suitable for the transition metal (3d) ions and another pocket (4O) suitable for lanthanide (4f) metal ions...
October 17, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Qiang Wang, Liping Huang, Yuzhen Pan, Xie Quan, Gianluca Li Puma
The role of Fe(III) was investigated as an electron-shuttle mediator to enhance the reduction rate of the toxic heavy metal hexavalent chromium (Cr(VI)) in wastewaters, using microbial fuel cells (MFCs). The direct reduction of chromate (CrO4(-)) and dichromate (Cr2O7(2-)) anions in MFCs was hampered by the electrical repulsion between the negatively charged cathode and Cr(VI) functional groups. In contrast, in the presence of Fe(III), the conversion of Cr(VI) and the cathodic coulombic efficiency in the MFCs were 65...
October 6, 2016: Journal of Hazardous Materials
Zain-Ul-Abdin, Li Wang, Haojie Yu, Muhammad Saleem, Muhammad Akram, Hamad Khalid, Nasir M Abbasi, Xianpeng Yang
Ferrocene-based derivatives are widely used as ferrocene-based burning rate catalysts (BRCs) for ammonium perchlorate (AP)-based propellant. However, in long storage, small ferrocene-based derivatives migrate to the surface of the propellant, which results in changes in the designed burning parameters and finally causes unstable combustion. To retard the migration of ferrocene-based BRCs in the propellant and to increase the combustion of the solid propellant, zero to third generation ethylene diamine-based ferrocene terminated dendrimers (0G, 1G, 2G and 3G) were synthesized...
October 4, 2016: Journal of Colloid and Interface Science
Gajendra Kumar Inwati, Yashvant Rao, Man Singh
Microwave irradiation was employed for spherical-shaped platinum nanoparticle (Pt NPs) preparation. Spherical Pt NPs indexed with (111) facets were prepared using Pt(II) precursor salt, glycerol as solvent and reducing agent, and polyvinylpyrrolidone (PVP) as a shape directer under microwave irradiation for 3-5 min at 300 °C. Electron spin resonance (ESR) peak at 336.000 mT (milli Tesla) confirmed the free radical formation from aqueous glycerol solution which acted as reducing species under microwave. The 2-8-nm diameter of particles was obtained by high-resolution transmission electron microscope...
December 2016: Nanoscale Research Letters
Ferdaous Maâtouk, Mouna Maâtouk, Karima Bekir, Houcine Barhoumi, Abderrazak Maaref, Hedi Ben Mansour
In this work we report the development of an electrochemical DNA biosensor with high sensitivity for mercury ion detection. A new matrix based on gold nanoparticles (AuNPs)-glutathione (GSH)/cysteine was investigated. The interaction between DNA oligonucleotides and Hg(2+) ions followed by the formation of Thymine-Hg(2+)-Thymine (T-Hg(2+)-T) structures was quantified using different electrochemical methods. It has been shown that the electrochemical impedance spectroscopy (EIS) measurements and the differential pulse voltammetry (DPV) confirmed the specific interaction between the oligonucleotide receptor layer and the Hg(2+) ions...
October 2016: Journal of Water and Health
Isacco Gualandi, Domenica Tonelli, Federica Mariani, Erika Scavetta, Marco Marzocchi, Beatrice Fraboni
An all PEDOT:PSS Organic Electrochemical Transistor (OECT) has been developed and used for the selective detection of dopamine (DA) in the presence of interfering compounds (ascorbic acid, AA and uric acid, UA). The selective response has been implemented using a potentiodynamic approach, by varying the operating gate voltage and the scan rate. The trans-conductance curves allow to obtain a linear calibration plot for AA, UA and DA and to separate the redox waves associated to each compound; for this purpose, the scan rate is an important parameter to achieve a good resolution...
October 14, 2016: Scientific Reports
Sharel Pei E, Yang-Rae Kim, David Perry, Cameron Luke Bentley, Patrick R Unwin
There is great interest in finding and developing new, efficient and more active electrocatalytic materials. Surface modification of highly oriented pyrolytic graphite (HOPG), through the introduction of surface "blisters", is demonstrated to result in an electrode material with greatly enhanced electrochemical activity. The increased electrochemical activity of these blisters, which are produced by electro-oxidation in HClO4, is revealed through the use of scanning electrochemical cell microscopy (SECCM), coupled with complementary techniques (optical microscopy, FE-SEM, Raman spectroscopy, and AFM)...
October 14, 2016: ACS Applied Materials & Interfaces
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