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https://www.readbyqxmd.com/read/28103020/diazatetracenes-derived-from-the-benzannulation-of-acetylenes-electronic-tuning-via-substituent-effects-and-external-stimuli
#1
Dan Lehnherr, Joaquin M Alzola, Catherine R Mulzer, William R Dichtel
Functionalized diazatetracenes are prepared using a new two-step sequence. The use of a dichlorobenzaldehyde in a Cu-catalyzed benzannulation of acetylenes provides functionalized dichloronaphthalenes that afford diazatetracenes using Buchwald-Hartwig aminations. This approach provides unique substitution patterns and rapid access to covalently linked dimeric diazatetracenes. Their electronic properties are characterized by UV-vis absorption/emission and cyclic voltammetry, revealing strong effects from both external stimuli by acid and internal substituent effects...
January 19, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28102678/a-self-assembled-cofacial-cobalt-porphyrin-prism-for-oxygen-reduction-catalysis
#2
Amanda N Oldacre, Alan E Friedman, Timothy R Cook
Herein we report the first study of the oxygen reduction reaction (ORR) catalyzed by a cofacial porphyrin scaffold accessed in high yield (overall 53%) using coordination-driven self-assembly with no chromatographic purification steps. The ORR activity was investigated using chemical and electrochemical techniques on monomeric cobalt(II) tetra(meso-4-pyridyl)porphyrinate (CoTPyP) and its cofacial analogue [Ru8(η(6)-iPrC6H4Me)8(dhbq)4(CoTPyP)2][OTf]8 (Co Prism) (dhbq = 2,5-dihydroxy-1,4-benzoquinato, OTf = triflate) as homogeneous oxygen reduction catalysts...
January 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28101932/amino-acid-profiling-of-zinc-resistant-prostate-cancer-cell-lines-associations-with-cancer-progression
#3
Monika Kratochvilova, Martina Raudenska, Zbynek Heger, Lukas Richtera, Natalia Cernei, Vojtech Adam, Petr Babula, Marie Novakova, Michal Masarik, Jaromir Gumulec
BACKGROUND: Failure in intracellular zinc accumulation is a key process in prostate carcinogenesis. Nevertheless, epidemiological studies of zinc administration have provided contradicting results. In order to examine the impact of the artificial intracellular increase of zinc(II) ions on prostate cancer metabolism, PNT1A, 22Rv1, and PC-3 prostatic cell lines-depicting different stages of cancer progression-and their zinc-resistant counterparts were used. To determine "benign" and "malignant" metabolic profiles, amino acid patterns, gene expression, and antioxidant capacity of these cell lines were assessed...
January 19, 2017: Prostate
https://www.readbyqxmd.com/read/28101855/improving-morphological-quality-and-uniformity-of-hydrothermally-grown-zno-nanowires-by-surface-activation-of-catalyst-layer
#4
Gonzalo Murillo, Helena Lozano, Joana Cases-Utrera, Minbaek Lee, Jaume Esteve
This paper presents a study about the dependence of the hydrothermal growth of ZnO nanowires (NWs) with the passivation level of the active surface of the Au catalyst layer. The hydrothermal method has many potential applications because of its low processing temperature, feasibility, and low cost. However, when a gold thin film is utilized as the seed material, the grown NWs often lack morphological homogeneity; their distribution is not uniform and the reproducibility of the growth is low. We hypothesize that the state or condition of the active surface of the Au catalyst layer has a critical effect on the uniformity of the NWs...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28101544/tetrathienyl-functionalized-red-and-nir-absorbing-bodipy-dyes-appending-various-peripheral-substituents
#5
Ping Liu, Feng Gao, Lina Zhou, Yu Chen, Zhijian Chen
A series of boron-dipyrromethene dyes (BODIPYs) 4a-g with different thienyl moieties at 2,3,5,6-positions of the BODIPY core were synthesized by the Stille cross-coupling reaction. The new compounds were characterized by (1)H NMR, (13)C NMR, HRMS, and IR spectroscopy. The single crystal structure of compound 4e was obtained by X-ray crystallography. The optical and electrochemical properties of these dyes were studied by UV/Vis spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. The DFT calculation of the frontier molecular orbitals of these dyes corroborates the observed effects of peripheral substituents on the optical and redox properties...
January 19, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28100828/an-integrated-modelling-framework-for-neural-circuits-with-multiple-neuromodulators
#6
Alok Joshi, Vahab Youssofzadeh, Vinith Vemana, T M McGinnity, Girijesh Prasad, KongFatt Wong-Lin
Neuromodulators are endogenous neurochemicals that regulate biophysical and biochemical processes, which control brain function and behaviour, and are often the targets of neuropharmacological drugs. Neuromodulator effects are generally complex partly owing to the involvement of broad innervation, co-release of neuromodulators, complex intra- and extrasynaptic mechanism, existence of multiple receptor subtypes and high interconnectivity within the brain. In this work, we propose an efficient yet sufficiently realistic computational neural modelling framework to study some of these complex behaviours...
January 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28100054/efficacy-of-silver-hydrophilic-poly-p-xylylene-on-preventing-bacterial-growth-and-biofilm-formation-in-urinary-catheters
#7
Hamideh Heidari Zare, Viktorija Juhart, Attila Vass, Gerhard Franz, Dieter Jocham
Catheter associated urinary tract infections (CAUTI), caused by several strains of bacteria, are a common complication for catheterized patients. This may eventually lead to a blockage of the catheter due to the formation of a crystalline or amorphous biofilm. Inhibiting bacteria should result in a longer application time free of complaints. This issue has been investigated using an innovative type of silver-coated catheter with a semipermeable cap layer to prevent CAUTI. In this work, two different types of silver catheters were investigated, both of which were capped with poly(p-xylylene) (PPX-N) and exhibited different surface properties that completely changed their wetting conduct with water...
January 18, 2017: Biointerphases
https://www.readbyqxmd.com/read/28098987/predicting-copper-speciation-in-estuarine-waters-is-dissolved-organic-carbon-a-good-proxy-for-the-presence-of-organic-ligands
#8
Holly Beverley Clare Pearson, Sean David W Comber, Charlotte Braungardt, Paul J Worsfold
A new generation of speciation-based aquatic environmental quality standards (EQS) for metals have been developed using models to predict the free metal ion concentration, the most ecologically relevant form, to set site-specific values. Some countries such as the UK have moved towards this approach by setting a new estuarine and marine water EQS for copper, based on an empirical relationship between copper toxicity to mussels (Mytilus sp.) and ambient dissolved organic carbon (DOC) concentrations. This assumes an inverse relationship between DOC and free copper ion concentration owing to complexation by predominantly organic ligands...
January 18, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28098979/electroactive-self-assembled-monolayers-detect-micelle-formation
#9
Eric R Dionne, Antonella Badia
The interfacial electrochemistry of self-assembled monolayers (SAMs) of ferrocenyldodecanethiolate on gold (FcC12SAu) electrodes is applied to detect the micellization of some common anionic surfactants, sodium n-alkyl sulfates, sodium n-alkyl sulfonates, sodium diamyl sulfosuccinate, and sodium dodecanoate, in aqueous solution by cyclic voltammetry. The apparent formal redox potential (Eº´SAM) of the FcC12SAu SAM is used to track changes in the concentration of the unaggregated surfactant anions and determine the critical micelle concentration (cmc)...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28098963/scaffolding-of-enzymes-on-virus-nanoarrays-effects-of-confinement-and-virus-organization-on-biocatalysis
#10
Anisha N Patel, Agnès Anne, Arnaud Chovin, Christophe Demaille, Eric Grelet, Thierry Michon, Cécilia Taofifenua
Organizing active enzyme molecules on nanometer-sized scaffolds is a promising strategy for designing highly efficient supported catalytic systems for biosynthetic and sensing applications. This is achieved by designing model nanoscale enzymatic platforms followed by thorough analysis of the catalytic activity. Herein, the virus fd bacteriophage is considered as an enzyme nanocarrier to study the scaffolding effects on enzymatic activity. Nanoarrays of randomly oriented, or directionally patterned, fd bacteriophage virus are functionalized with the enzyme glucose oxidase (GOx), using an immunological assembly strategy, directly on a gold electrode support...
January 18, 2017: Small
https://www.readbyqxmd.com/read/28098440/corrosion-protection-of-copper-using-al2o3-tio2-zno-hfo2-and-zro2-atomic-layer-deposition
#11
James S Daubert, Grant T Hill, Hannah N Gotsch, Antoine P Gremaud, Jennifer S Ovental, Philip S Williams, Christopher J Oldham, Gregory N Parsons
Atomic layer deposition (ALD) is a viable means to add corrosion protection to copper metal. Ultrathin films of Al2O3, TiO2, ZnO, HfO2, and ZrO2 were deposited on copper metal using ALD, and their corrosion protection properties were measured using electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). Analysis of ∼50 nm thick films of each metal oxide demonstrated low electrochemical porosity and provided enhanced corrosion protection from aqueous NaCl solution. The surface pretreatment and roughness was found to affect the extent of the corrosion protection...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28097871/redox-responsive-self-assembly-micelles-from-poly-n-acryloylmorpholine-block-2-acryloyloxyethyl-ferrocene-carboxylate-amphiphilic-block-copolymers-as-drug-release-carriers
#12
Feng Xu, He Li, Yan-Ling Luo, Wei Tang
Novel well-defined redox-responsive ferrocene-containing amphiphilic block copolymers (PACMO-b-PAEFC) were synthesized by ATRP, with poly(N-acryloylmorpholine) (PACMO) as hydrophilic blocks and poly(2-acryloyloxyethyl ferrocenecarboxylate) (PAEFC) as hydrophobic blocks. The copolymers were characterized by FTIR, 1H NMR, and gel permeation chromatography, and the crystalline behavior was determined by X-ray diffraction and small-angle X-ray scattering. The results showed that the size of the lamellar crystals and crystallinity vary with the systematic compositions while the periodic structure of the lamellar stacks has no obvious change...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28094947/synthesis-of-2-azulenyltetrathiafulvalenes-by-palladium-catalyzed-direct-arylation-of-2-chloroazulenes-with-tetrathiafulvalene-and-their-optical-and-electrochemical-properties
#13
Taku Shoji, Takanori Araki, Shuhei Sugiyama, Akira Ohta, Ryuta Sekiguchi, Shunji Ito, Tetsuo Okujima, Kozo Toyota
Tetrathiafulvalene (TTF) derivatives with 2-azulenyl substituents 5-11 were prepared by the palladium-catalyzed direct cross-coupling reaction of 2-chloroazulenes with TTF in good yield. Photophysical properties of these compounds were investigated by UV-vis spectra and theoretical calculations. Redox behavior of the novel azulene-substituted TTFs was examined by using cyclic voltammetry and differential pulse voltammetry, which revealed their multistep electrochemical oxidation and/or reduction properties...
January 17, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28094353/surfactant-free-synthesis-of-three-dimensional-nitrogen-doped-hierarchically-porous-carbon-and-its-application-as-an-electrode-modification-material-for-simultaneous-sensing-of-ascorbic-acid-dopamine-and-uric-acid
#14
Anaclet Nsabimana, Jianping Lai, Suping Li, Pan Hui, Zhongyuan Liu, Guobao Xu
Three-dimensional N-doped hierarchically porous carbon (3D NHPC) was synthesized successfully without using any surfactant or etching agent. This simple and effective synthesis method was accomplished by solvothermal synthesis followed by pyrolysis. The physical morphology and chemical composition of 3D NHPC were verified by scanning electron microscopy, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy. Its structural studies reveal that it exhibits a micro-mesoporous hierarchical structure and contains C, O and N atoms forming different functional groups...
January 17, 2017: Analyst
https://www.readbyqxmd.com/read/28094255/specific-and-sensitive-isothermal-electrochemical-biosensor-for-plant-pathogen-dna-detection-with-colloidal-gold-nanoparticles-as-probes
#15
Han Yih Lau, Haoqi Wu, Eugene J H Wee, Matt Trau, Yuling Wang, Jose R Botella
Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV)...
January 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28093592/synthesis-and-optical-and-electrochemical-properties-of-julolidine-structured-pyrido-3-4-b-indole-dye
#16
Toshiaki Enoki, Keishi Matsuo, Joji Ohshita, Yousuke Ooyama
The julolidine-structured pyrido[3,4-b]indole dye ET-1 has been newly designed and developed as a small D-A fluorescent dye. ET-1 showed bathochromic shifts of the fluorescence band upon changing from aprotic solvents to protic solvents, as well as positive fluorescence solvatochromism. Moreover, it was found that ET-1 can form a 1 : 1 Py(N)-B complex with boron trifluoride and a hydrogen-bonded proton transfer (Py(N)-H) complex with trifluoroacetic acid, which exhibit photoabsorption and fluorescence bands at a longer wavelength region than the pristine ET-1...
January 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28092817/porous-bimetallic-pdni-catalyst-with-high-electrocatalytic-activity-for-ethanol-electrooxidation
#17
Yue Feng, Duan Bin, Bo Yan, Yukou Du, Tetsuro Majima, Weiqiang Zhou
Porous bimetallic PdNi catalysts were fabricated by a novel method, namely, reduction of Pd and Ni oxides prepared via calcining the complex chelate of PdNi-dimethylglyoxime (PdNi-dmg). The morphology and composition of the as-prepared PdNi were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Furthermore, the electrochemical properties of PdNi catalysts towards ethanol electrooxidation were also studied by electrochemical impedance spectrometry (EIS), cyclic voltammetry (CV) and chronoamperometry (CA) measurement...
January 11, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28092438/biofunctionalization-of-nerve-interface-via-biocompatible-polymer-roughened-pt-black-on-cuff-electrode-for-chronic-recording
#18
Yi Jae Lee, Han-Jun Kim, Ji Yoon Kang, Sun Hee Do, Soo Hyun Lee
Peripheral nerve cuff electrodes with roughened Pt black (BPt) are coated with polyethylene glycol (PEG) and Nafion (NF). Although the influence of coated PEG and Nafion on roughened BPt on the electrical properties is weak, the cuff electrode with BPt/PEG and BPt/Nafion exhibits some very important properties. For example, it markedly decreases interfacial impedance, increases charge storage capacity (CSC) due to retaining the BPt surface structure, good stability without exfoliation in repetitive cyclic voltammetry scanning because it is protected by PEG or Nafion coating...
January 16, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28088565/rapid-microwave-assisted-growth-of-silver-nanoparticles-on-3d-graphene-networks-for-supercapacitor-application
#19
S Khamlich, T Khamliche, M S Dhlamini, M Khenfouch, B M Mothudi, M Maaza
Silver nanoparticles (AgNPs) grown on a three dimensional (3d) graphene networks (GNs) has been successfully prepared by an efficient and rapid microwave-assisted growth process to form GNs/AgNPs nanocomposite electrode materials for supercapacitor application. The 3d nature of the used GNs offers a unique architecture, which creates an efficient conduction networks and maximum utilization of space and interface, and acts as a conductive layer for the deposited AgNPs. The electrochemical performances of the fabricated electrode were evaluated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) tests...
January 7, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28088279/archaeometric-analysis-of-roman-bronze-coins-from-the-magna-mater-temple-using-solid-state-voltammetry-and-electrochemical-impedance-spectroscopy
#20
Francesca Di Turo, Noemí Montoya, Joan Piquero-Cilla, Caterina De Vito, Fulvio Coletti, Gabriele Favero, Antonio Doménech-Carbó
Voltammetry of microparticles (VMP) and electrochemical impedance spectroscopy (EIS) techniques, complemented by SEM-EDX and Raman spectroscopy, were applied to a set of 15 Roman bronze coins and one Tessera from the temple of Magna Mater (Rome, Italy). The archaeological site, dated back between the second half and the end of the 4th century A.D., presented a complicated stratigraphic context. Characteristic voltammetric patterns for cuprite and tenorite for sub-microsamples of the corrosion layers of the coins deposited onto graphite electrodes in contact with 0...
February 22, 2017: Analytica Chimica Acta
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