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acid base strong ion

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https://www.readbyqxmd.com/read/28516780/dual-colored-carbon-dots-ratiometric-fluorescent-test-paper-based-on-a-specific-spectral-energy-transfer-for-semi-quantitative-assay-of-copper-ions
#1
Cui Liu, Dianhua Ning, Cheng Zhang, Zhengjie Liu, Ruilong Zhang, Jun Zhao, Tingting Zhao, Bianhua Liu, Zhongping Zhang
Classical pH test papers are widely employed to measure the acid-base degree of media in a qualitative and semi-quantitative way. However, the extension of the portable and inexpensive methods to a wide range of analytes so as to liberate us from the tediousness of instrumental assays remains unsuccessful. Here, we report a novel kind of dual-colored carbon dots (CDs) ratiometric-fluorescent test paper for the semi-quantitative assay of copper ions (Cu2+) by a dosage-sensitive color evolution. The creation of the test paper is based on the two interesting findings: on the one hand, the residual p-phenylenediamine (p-PDA) at the surface of as-synthesized red-emissive CDs (r-CDs) efficiently binds Cu2+ ions to produce a strong visible absorption that overlaps with the emission of blue CDs (b-CDs), on the other hand, Cu2+ ions render small b-CDs adsorbed onto the surface of larger-sized r-CDs through its dual-coordinating interactions with the surface ligands of both r-CDs and b-CDs...
May 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28513744/high-affinity-recognition-of-the-human-c-reactive-protein-independent-of-phosphocholine
#2
Jie Yang, Anna-Lena Gustavsson, Martin Haraldsson, Göran Karlsson, Thomas Norberg, Lars Baltzer
A high-affinity polypeptide conjugate 4-C25L22-DQ, has been developed for the molecular recognition of the human C-reactive protein, CRP, a well-known inflammation biomarker. CRP is one of the most frequently quantified targets in diagnostic applications and a target in drug development. With the exception of antibodies, most molecular constructs take advantage of the known affinity for CRP of phosphocholine that depends on Ca(2+) for its ability to bind. 4-C25L22-DQ which is unrelated to phosphocholine binds in the absence of Ca(2+) with a dissociation constant of 760 nM, an order of magnitude lower than that of phosphocholine, the KD of which is 5 μM...
May 17, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28513661/a-zwitterionic-hydrocarbon-soluble-borenium-ion-based-on-a-%C3%AE-diketiminate-backbone
#3
Joseph A B Abdalla, Rémi C Tirfoin, Haoyu Niu, Simon Aldridge
A versatile synthetic route has been developed to access strongly Lewis acidic borenium cations (and heavier group 13 analogues) featuring a pendant weakly-coordinating borate function. The hydrocarbon-soluble borenium/borate zwitterion is more strongly Lewis acidic than B(C6F5)3, despite featuring a pendant (non-fluorinated) aryl group and two flanking N-donors.
May 17, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28511933/an-initial-demonstration-of-hierarchically-porous-niobium-alkylphosphonates-coordination-polymers-as-potent-radioanalytical-separation-materials
#4
Kai Lv, Chu-Ting Yang, Jun Han, Sheng Hu, Xiao-Lin Wang
Combining the merits of soft-templating and perchlorate oxidation methods, the first-case investigation of niobium alkylphosphonates has uncovered their unique morphology, backbone composition, thermal behavior and huge potentiality as radioanalytical separation materials. These hierarchically porous solids are random aggregates of densely stacked nanolayers perforated with worm-like holes or vesicular voids, manifesting the massif-, tower-like "polymer brush" elevated up to ∼150nm driven by the minimal surface free energy principle...
May 8, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28509360/supramolecular-assembly-mediated-by-metal-ions-in-aqueous-solution-and-their-analysis-application
#5
Jing Zhang, Qing Tang, Zhongzheng Gao, Sheng Chao Qiu, Ying Huang, Zhu Tao
A water-soluble fluorescent sensor based on the interaction of the twisted cucurbit[14]uril (tQ[14]) and thiazole orange (TO) in aqueous solution has been developed. Formation of the tQ[14]/TO complex gives rise to strong fluorescence in both of neutral and acidic aqueous solutions compared with that of free TO. Further experiments on the interaction of the tQ[14]/TO complex with metal ions revealed that from a series of nineteen selected common metal ions, 1) only Hg2+ ion can lead to the fluorescence enhancement and then quenching of the tQ[14]/TO complex (2:1) in neutral aqueous solution; 2) only Ba2+ can induce fluorescence quenching of the tQ[14]/TO (2:1) complex in aqueous HCl solution (pH 2)...
May 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28494363/reductive-solidification-stabilization-of-chromate-in-municipal-solid-waste-incineration-fly-ash-by-ascorbic-acid-and-blast-furnace-slag
#6
Xian Zhou, Min Zhou, Xian Wu, Yi Han, Junjun Geng, Teng Wang, Sha Wan, Haobo Hou
Fly ash is a hazardous byproduct of municipal solid waste incineration (MSWI). Cementitious material that is based on ground-granulated blast furnace slag (GGBFS) has been tested and proposed as a binder to stabilize Pb, Cd, and Zn in MSWI fly ash (FA). Cr, however, still easily leaches from MSWI FA. Different reagents, such as ascorbic acid (VC), NaAlO2, and trisodium salt nonahydrate, were investigated as potential Cr stabilizers. The results of the toxicity characteristic leaching procedure (TCLP) showed that VC significantly improved the stabilization of Cr via the reduction of Cr(VI) to Cr(III)...
April 21, 2017: Chemosphere
https://www.readbyqxmd.com/read/28494246/catalytic-hydrodechlorination-of-triclosan-using-a-new-class-of-anion-exchange-resin-supported-palladium-catalysts
#7
Bing Han, Wen Liu, Jingwen Li, Jin Wang, Dongye Zhao, Rui Xu, Zhang Lin
We prepared a new class of anion-exchange-resin supported Pd catalysts for efficient hydrodechlorination of triclosan in water. The catalysts were prepared through an initial ion-exchange uptake of PdCl4(2-) and subsequent reduction of Pd(II) to Pd(0) nanoparticles at ambient temperature. Two standard strong-base anion exchange resins (IRA-900 and IRA-958) with different matrices (polystyrene and polyacrylic) were chosen as the supports. SEM and TEM images showed that Pd(0) nanoparticles were evenly attached on the resin surface with a mean size of 3-5 nm...
April 26, 2017: Water Research
https://www.readbyqxmd.com/read/28485833/a-near-infrared-dye-that-undergoes-multiple-interconversions-through-acid-base-equilibrium-and-reversible-redox-processes
#8
Kengo Asai, Aiko Fukazawa, Shigehiro Yamaguchi
A near-infrared (NIR) polymethine dye (1), consisting of a cyclohepta[1,2-b;4,3-b']dithiophene and two phenol moieties, was synthesized. This dye exhibited pH-responsive changes in its photophysical properties due to a two-step acid-base equilibrium that produced a protonated cation (1H(+) ) and an anion (1(-) ). While 1H(+) showed an intense fluorescence in the red region of the visible spectrum, 1(-) exhibited a strong absorption in the NIR region. The tropylium ion character in 1H(+) induces high pKa1 and pKa2 values for 1...
May 9, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28472842/diterpene-lipo-alkaloids-with-selective-activities-on-cardiac-k-channels
#9
Tivadar Kiss, Botond Borcsa, Péter Orvos, László Tálosi, Judit Hohmann, Dezső Csupor
Aconitum diterpene alkaloids are known for their remarkable toxicity, which is due to their effect on ion channels. Activation of voltage-gated Na(+) channels is the major cause of their cardiotoxicity, however, influence on K(+) channels may also play a role in the overall effect.Here we report the synthesis of a series of lipo-alkaloids, including four new compounds, based on the 14-benzoylaconine structure, which is the core of a vast number of diterpene alkaloids naturally occurring in Aconitum species...
May 4, 2017: Planta Medica
https://www.readbyqxmd.com/read/28470253/in-silico-analysis-of-interaction-pattern-switching-in-ligandreceptor-binding-in-golgi-%C3%AE-mannosidase-ii-induced-by-the-protonated-states-of-inhibitors
#10
V Sladek, J Kóňa, H Tokiwa
Golgi α-mannosidase II (GM) is a pharmaceutical target for the design of inhibitors with anticancer activity. The known potent GM inhibitors undergo complex interactions with Zn(2+) ions and the active-site amino acids, many of which contain ionisable functional groups. Herein, the physical insight into the ligandreceptor interactions has been provided based on energy decomposition techniques: SAPT (symmetry adapted perturbation theory) and FMO-PIEDA (fragment molecular orbital-pair interaction energy decomposition analysis) for a large GM active-site cluster...
May 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28468242/polymer-electrolyte-membranes-for-water-photo-electrolysis
#11
Antonino S Aricò, Mariarita Girolamo, Stefania Siracusano, David Sebastian, Vincenzo Baglio, Michael Schuster
Water-fed photo-electrolysis cells equipped with perfluorosulfonic acid (Nafion(®) 115) and quaternary ammonium-based (Fumatech(®) FAA3) ion exchange membranes as separator for hydrogen and oxygen evolution reactions were investigated. Protonic or anionic ionomer dispersions were deposited on the electrodes to extend the interface with the electrolyte. The photo-anode consisted of a large band-gap Ti-oxide semiconductor. The effect of membrane characteristics on the photo-electrochemical conversion of solar energy was investigated for photo-voltage-driven electrolysis cells...
April 29, 2017: Membranes
https://www.readbyqxmd.com/read/28467507/nectar-sugars-and-amino-acids-in-day-and-night-flowering-nicotiana-species-are-more-strongly-shaped-by-pollinators-preferences-than-organic-acids-and-inorganic-ions
#12
Kira Tiedge, Gertrud Lohaus
Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences...
2017: PloS One
https://www.readbyqxmd.com/read/28466966/luminescent-probing-of-the-simplest-chiral-%C3%AE-amino-acid-alanine-in-an-enantiopure-and-racemic-state
#13
Arkadii V Tarasevych, Anton I Kostyukov, Mark G Baronskiy, Alexander A Rastorguev, Jean-Claude Guillemin, Valeriy N Snytnikov
Luminescent spectroscopy combined with the technique of luminescent probing with rare earth ions (europium, gadolinium, terbium) and an actinide ion (uranyl) was used to differentiate enantiopure and racemic alanine, the simplest chiral proteinogenic amino acid. Using the achiral luminescent probes, small differences between pure L and DL alanine in the solid state were strongly amplified. Based on the observed electronic transitions of the probes, the position of the triplet level of the coordinated alanine was estimated...
May 3, 2017: Chirality
https://www.readbyqxmd.com/read/28452475/hydrolysis-in-acidic-environment-and-degradation-of-satraplatin-a-joint-experimental-and-theoretical-investigation
#14
Ida Ritacco, Merriam Al Assy, Mohamed K Abd El-Rahman, Sherif Ashraf Fahmy, Nino Russo, Tamer Shoeib, Emilia Sicilia
For the synthesis and selection of active platinum-based anticancer drugs that perform better than cisplatin and its analogues, six-coordinate octahedral Pt(IV) complexes appear to be promising candidates as, being kinetically more inert and more resistant to ligand substitution than four-coordinate Pt(II) centers, they are able to minimize unwanted side reactions with biomolecules prior to DNA binding. Due to their kinetic inertness, Pt(IV) complexes have also been exploited to bypass inconvenient intravenous administration...
April 28, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28433060/enhanced-photoresponsive-polyethyleneimine-citric-acid-co-carbonized-dots-for-facile-and-selective-sensing-and-intracellular-imaging-of-cobalt-ions-at-physiologic-ph
#15
Wen-Sheng Zou, Qing-Chun Zhao, Jun Zhang, Xiao-Ming Chen, Xiu-Fang Wang, Lin Zhao, Shao-Hua Chen, Ya-Qin Wang
Whether as an important biological element or as a radioactive source/medicine, the monitoring of trace levels of cobalt ions (Co) has become a non-negligible factor for human health and green environment. Current technologies for the detection of Co are cost-expensive and time-consuming, and require cumbersome sample pretreatment process. Herein a novel sensing platform has been developed for Co detection based on the quenching of the enhanced fluorescence signal of polyamine functionalized C-dots. Amine groups at the surface of the C-dots can capture Zn(2+)/Cd(2+) to form coordination compound, which can inhibit the photoinduced electron transfer pathways of C-dots and then induce the fluorescence enhancement of the C-dots by ∼80% margin...
June 1, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28426209/channel-assisted-proton-conduction-behavior-in-hydroxyl-rich-lanthanide-based-magnetic-metal-organic-frameworks
#16
Soumava Biswas, Jayita Chakraborty, Vijay Singh Parmar, Siba Prasad Bera, Nirmal Ganguli, Sanjit Konar
Two new lanthanide-based 3D metal-organic frameworks (MOFs), {[Ln(L)(Ox)(H2O)]n·xH2O} [Ln = Gd(3+) and x = 3 (1) and Dy(3+) and x = 1.5 (2); H2L = mucic acid; OxH2 = oxalic acid] showing interesting magnetic properties and channel-mediated proton conduction behavior, are presented here. Single-crystal X-ray structure analysis shows that, in complex 1, the overall structure originates from the mucate-bridged gadolinium-based rectangular metallocycles. The packing view reveals the presence the two types of hydrophilic 1D channels filled with lattice water molecules, which are strongly hydrogen-bonded with coordinated water along the a and b axes, whereas for complex 2, the 3D framework originates from a carboxylate-bridged dysprosium-based criss-cross-type secondary building block...
April 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28425293/cosensitized-porphyrin-system-for-high-performance-solar-cells-with-tof-sims-analysis
#17
Wenjun Wu, Huaide Xiang, Wei Fan, Jinglin Wang, Haifeng Wang, Xin Hua, Zhaohui Wang, Yitao Long, He Tian, Wei-Hong Zhu
To date, development of organic sensitizers has been predominately focused on light harvesting, highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels, and the electron transferring process. In contrast, their adsorption mode as well as the dynamic loading behavior onto nanoporous TiO2 is rarely considered. Herein, we have employed the time-of-flight secondary ion mass spectrometry (TOF-SIMS) to gain insight into the competitive dye adsorption mode and kinetics in the cosensitized porphyrin system...
May 2, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28420042/determination-of-reference-intervals-of-acid-base-parameters-in-clinically-healthy-dogs
#18
Ivana Vanova-Uhrikova, Leona Rauserova-Lexmaulova, Kristina Rehakova, Peter Scheer, Jaroslav Doubek
OBJECTIVE: To establish reference intervals for traditionally- and Stewart's approach-determined acid-base parameters in a population of clinically healthy dogs. DESIGN: Prospective study (June 2011-September 2012). SETTING: Veterinary teaching hospital. ANIMALS: Two hundred twenty-four client-owned, clinically healthy dogs. INTERVENTIONS: Blood was collected from the jugular vein and the dorsal pedal artery...
May 2017: Journal of Veterinary Emergency and Critical Care
https://www.readbyqxmd.com/read/28414912/observation-of-photovoltaic-action-from-photoacid-modified-nafion-due-to-light-driven-ion-transport
#19
William White, Christopher D Sanborn, Ronald S Reiter, David M Fabian, Shane Ardo
Replacing passive ion-exchange membranes, like Nafion, with membranes that use light to drive ion transport would allow membranes in photoelectrochemical technologies to serve in an active role. Toward this, we modified perfluorosulfonic acid ionomer membranes with organic pyrenol-based photoacid dyes to sensitize the membranes to visible light and initiate proton transport. Covalent modification of the membranes was achieved by reacting Nafion sulfonyl fluoride poly(perfluorosulfonyl fluoride) membranes with the photoacid 8-hydroxypyrene-1,3,6-tris(2-aminoethylsulfonamide)...
May 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28407573/assessment-of-mobility-and-bioavailability-of-mercury-compounds-in-sewage-sludge-and-composts
#20
Beata Janowska, Kazimierz Szymański, Robert Sidełko, Izabela Siebielska, Bartosz Walendzik
Content of heavy metals, including mercury, determines the method of management and disposal of sewage sludge. Excessive concentration of mercury in composts used as organic fertilizer may lead to accumulation of this element in soil and plant material. Fractionation of mercury in sewage sludge and composts provides a better understanding of the extent of mobility and bioavailability of the different mercury species and helps in more informed decision making on the application of sludge for agricultural purposes...
April 10, 2017: Environmental Research
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