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Qian Gao, Weixiao Chen, Yin Chen, David Werner, Gerard Cornelissen, Baoshan Xing, Shu Tao, Xilong Wang
The ability of multiwalled carbon nanotubes (MWCNTs) to remove a non-ionic surfactant, Triton X-100 (TX100), an anionic surfactant, sodium dodecylbenzenesulonate (SDBS), and a cationic surfactant, hexadecyltrimethylammonium bromide (CTAB) from the aqueous phase was investigated. Untreated, OH-, and COOH-functionalized MWCNTs with different outer diameters and chemical composition were examined and compared. As both the concentrations of surfactants and MWCNTs initially added may affect removal efficiency of surfactants, a relationship between the initial concentration ratio of surfactants and MWCNTs (Rc) and the removal efficiency (E) was established...
October 11, 2016: Water Research
Friardi Ismed, Françoise Lohézic-Le Dévéhat, Isabelle Rouaud, Solenn Ferron, Amri Bakhtiar, Joël Boustie
The phytochemical study of Stereocaulon montagneanum harvested in Sumatra (Indonesia) led to the isolation of 11 known compounds including two metabolites not previously described in the genus Stereocaulon, peristictic acid (8) and menegazziaic acid (10). The complete 1H and 13C NMR spectral assignments of stictic acid derivatives are reported with some revisions. Five depsidones belonging to the stictic acid chemosyndrome were superoxide anion scavengers as potent as ascorbic acid and with no toxicity on two human cell lines...
October 22, 2016: Zeitschrift Für Naturforschung. C, A Journal of Biosciences
Zhifeng Liu, Mingda Yu, Guangming Zeng, Min Li, Jiachao Zhang, Hua Zhong, Yang Liu, Binbin Shao, Zhigang Li, Zhiquan Wang, Guansheng Liu, Xin Yang
Micellar-enhanced ultrafiltration (MEUF) processes of resorcinol, phenol, and 1-Naphthol with rhamnolipid as an anionic biosurfactant were investigated using polysulfone membrane. The effects of retentate/permeate concentration of phenolic pollutants (C R/C P), distribution coefficient of phenolic pollutions (D), concentration ratios of phenolic pollutions (α P) and rhamnolipids (α R) and adsorption capacity of the membrane (N m) were studied by operating pressure, pH condition, feed surfactant, and phenolic pollution concentrations...
October 21, 2016: Environmental Science and Pollution Research International
A R Fetoni, R Rolesi, F Paciello, S L M Eramo, C Grassi, D Troiani, G Paludetti
Experimental and human investigations have raised the level of concern about the potential ototoxicity of organic solvents and their interaction with noise. The main objective of this study was to characterize the effects of the combined noise and styrene exposure on hearing focusing on the mechanism of damage on the sensorineural cells and supporting cells of the organ of Corti and neurons of the ganglion of Corti. The impact of single and combined exposures on hearing was evaluated by auditory functional testing and histological analyses of cochlear specimens...
October 18, 2016: Free Radical Biology & Medicine
Michaela L Sundqvist, Jon O Lundberg, Eddie Weitzberg
The nitrate-nitrite-nitric oxide pathway has emerged as a significant source of nitric oxide (NO) bioactivity. Dietary intake of inorganic nitrate has a number of cardiovascular effects as well as a decrease in oxygen cost during exercise and a reduction in resting metabolic rate (RMR). Oral bacteria have a key role in bioactivation of inorganic nitrate since they catalyse the conversion of salivary nitrate to the more reactive nitrite anion. Recent studies demonstrate that blood pressure increases with the use of an antiseptic mouthwash, indicating that endogenous, NO-synthase derived nitrate is recycled into nitrite and NO, sufficiently to modulate cardiovascular function...
October 18, 2016: Nitric Oxide: Biology and Chemistry
Jie Gao, Narasimha Midde, Jun Zhu, Alvin V Terry, Campbell McInnes, James M Chapman
Using molecular modeling and rationally designed structural modifications, the multi-target structure-activity relationship for a series of ranitidine analogs has been investigated. Incorporation of a variety of isosteric groups indicated that appropriate aromatic moieties provide optimal interactions with the hydrophobic and π-π interactions with the peripheral anionic site of the AChE active site. The SAR of a series of cyclic imides demonstrated that AChE inhibition is increased by additional aromatic rings, where 1,8-naphthalimide derivatives were the most potent analogs and other key determinants were revealed...
October 6, 2016: Bioorganic & Medicinal Chemistry Letters
Félix Zapata, Mª Ángeles Fernández de la Ossa, Elizabeth Gilchrist, Leon Barron, Carmen García-Ruiz
Concerning the dreadful global threat of terrorist attacks, the detection of explosive residues in biological traces and marks is a current need in both forensics and homeland security. This study examines the potential of Raman microscopy in comparison to liquid chromatography (ion chromatography (IC) and reversed-phase high performance liquid chromatography (RP-HPLC)) to detect, identify and quantify residues in human handmarks of explosives and energetic salts commonly used to manufacture Improvised Explosive Devices (IEDs) including dynamite, ammonium nitrate, single- and double-smokeless gunpowders and black powder...
December 1, 2016: Talanta
Chencheng Sun, Bowen Xiong, Yang Pan, Hao Cui
Polyaniline (PANI) prepared by chemical oxidation was studied for adsorption removal of tannic acid (TA) from aqueous solution. Batch adsorption studies were carried out under different adsorbent dosages, pH, ionic strength, initial TA concentration and coexisting anions. Solution pH had an important impact on TA adsorption onto PANI with optimal removal in the pH range of 8-11. TA adsorption on PANI at three ionic strength levels (0.02, 0.2 and 2molL(-1) NaCl) could be well described by Langmuir model (monolayer adsorption process) and the maximum adsorption capacity was 230, 223 and 1023mgg(-1), respectively...
October 15, 2016: Journal of Colloid and Interface Science
Kirilka Mladenova, Svetla D Petrova, Tonya D Andreeva, Veselina Moskova-Doumanova, Tanya Topouzova-Hristova, Yuri Kalvachev, Konstantin Balashev, Shomi S Bhattacharya, Christina Chakarova, Zdravko Lalchev, Jordan A Doumanov
Human bestrophin-1 (hBest1) is a transmembrane calcium-activated chloride channel protein - member of the bestrophin family of anion channels, predominantly expressed in the membrane of retinal pigment epithelium (RPE) cells. Mutations in the protein cause ocular diseases, named Bestrophinopathies. Here, we present the first Fourier transform infrared (FTIR) study of the secondary structure elements of hBest1, π/A isotherms and hysteresis, Brewster angle microscopy (BAM) and atomic force microscopy (AFM) visualization of the aggregation state of protein molecules dispersed as Langmuir and Langmuir-Blodgett films...
October 13, 2016: Colloids and Surfaces. B, Biointerfaces
Matteo Bonomo, Danilo Dini, Andrea Giacomo Marrani
The adsorption of I(-) and I3(-) anions, i.e. the two species constituting the most common redox couple of dye-sensitized solar cells (DSCs), onto the surface of screen-printed nanoporous NiO was studied by means of X-ray photoelectron spectroscopy (XPS). Mesoporous NiO films were deposited on transparent metallic fluorine-doped tin oxide (FTO) and polarized as working electrodes in a three-electrode cell with differently concentrated I(-)/I3(-) electrolytes to simulate the different conditions experienced by the NiO cathodes during the lifecycle of a p-type DSC (p-DSC) at those atomic sites not passivated by the dye...
October 21, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Majid Jafari, Faramarz Mehrnejad
Changes in the tertiary structure of proteins and the resultant fibrillary aggregation could result in fatal heredity diseases, such as lysozyme systemic amyloidosis. Human lysozyme is a globular protein with antimicrobial properties with tendencies to fibrillate and hence is known as a fibril-forming protein. Therefore, its behavior under different ambient conditions is of great importance. In this study, we conducted two 500000 ps molecular dynamics (MD) simulations of human lysozyme in sodium dodecyl sulfate (SDS) at two ambient temperatures...
2016: PloS One
Qingwen Lin, Jiali Chang, Mengfan Gao, Hongzhu Ma
Epichlorohydrin cross-linked carboxymethyl cellulose microspheres (ECH/CMC) obtained by inverse suspension method and magnetic Fe3O4 nanoparticles encasing the ECH/CMC microspheres (M-ECH/CMC) obtained by two different methods were successfully prepared and compared. Their structures and morphologies were analyzed using polarizing microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The adsorption behaviors of M1-ECH/CMC for methylene blue (MB) in the single cationic dye wastewater, the cationic/anionic dye mixture in the absence or presence of co-existed additives (salt and surfactant) wastewater, were also investigated with UV-vis spectrometer...
October 21, 2016: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
Jinchun Qiu, Daniel K Unruh, Anthony Frank Cozzolino
Density Functional Theory calculations were used to design an anion receptor that utilizes antimony(III) secondary bonding interactions. Calculations were performed on promising motifs found in the chemical literature where two antimony sites were found in close proximity to a halide anion. The study was extended to a structurally related class of 1,3,2-benzodioxastibole derivatives to elucidate their potential for binding halide ions. Multiple geometric conformations were evaluated and various ratios of halide anions were considered...
October 21, 2016: Journal of Physical Chemistry. A
Michelle R Robinson, Jennifer S Brodbelt
Tyrosine sulfation is an important post-translational modification but remains difficult to detect in biological samples owing to its low stoichiometric abundance and the lack of effective enrichment methods. In the present study, weak anion exchange (WAX) is evaluated for the enrichment of sulfopeptides that have been modified via carbamylation to convert all primary amines to less basic carbamates. The decrease in basicity enhanced the binding of carbamylated sulfopeptides to WAX resin relative to non-sulfated peptides...
October 21, 2016: Analytical Chemistry
Oriana Brea, Ines Corral Perez, Otilia Mo, Manuel Yañez, Ibon Alkorta, Jose Elguero
Through the use of high-level ab initio and density functional calculations we have shown that 1,8-diBeX-naphthalene (X = H, F, Cl, CN, CF₃, C(CF₃)₃) derivatives behave as anion sponges, very much as 1,8-bis(dimethylamino)naphthalene derivatives behave as proton sponges. The electron deficient nature of the BeX substituents, which favors strong charge transfer from the anion towards the former, results into anion affinities which are among the largest ones reported in the literature for single neutral molecules...
October 21, 2016: Chemistry: a European Journal
Katharina Duda, Alexander Himmelspach, Johannes Landmann, Florian Kraus, Maik Finze
Deboronation of closo-1,7-C2B10H12 and 1-R(1)-closo-1,2-C2B10H12 (R(1) = Me, Ph) with anhydrous [Me4N]F yields [Me4N][BHF3] that is the first structurally characterized anion of the series [BHxF4-x](-) (x = 1-3). Deboronation of 9,12-R(2)2-closo-1,7-C2B10H12 (R(2) = H, I) gives a mixture of [Me4N][BHF3] and [Me4N][1-HF2B-9,12-R(2)2-closo-1,2-C2B10H9].
October 21, 2016: Chemical Communications: Chem Comm
Xiangyi Zhang, Gavin O Jones, James L Hedrick, Robert M Waymouth
Ring-opening polymerization of lactones is a versatile approach to generate well-defined functional polyesters. Typical ring-opening catalysts are subject to a trade-off between rate and selectivity. Here we describe an effective catalytic system combining alkoxides with thioureas that catalyses rapid and selective ring-opening polymerizations. Deprotonation of thioureas by sodium, potassium or imidazolium alkoxides generates a hydrogen-bonded alcohol adduct of the thiourea anion (thioimidate). The ring-opening polymerization of L-lactide mediated by these alcohol-bonded thioimidates yields highly isotactic polylactide with fast kinetics and living polymerization behaviour, as evidenced by narrow molecular weight distributions (Mw/Mn < 1...
November 2016: Nature Chemistry
Wei Zhang, M Can Gulersonmez, Thomas Hankemeier, Rawi Ramautar
In metabolomics, a wide range of analytical techniques is used for the global profiling of (endogenous) metabolites in complex samples. In this paper, a protocol is presented for the analysis of anionic and cationic metabolites in biological samples by capillary electrophoresis-mass spectrometry (CE-MS). CE is well-suited for the analysis of highly polar and charged metabolites as compounds are separated on the basis of their charge-to-size ratio. A recently developed sheathless interfacing design, i.e., a porous tip interface, is used for coupling CE to electrospray ionization (ESI) MS...
October 1, 2016: Journal of Visualized Experiments: JoVE
Frantz Le Dévédec, Loujin Houdaihed, Christine Allen
In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE). Characterization of the copolymer revealed a narrow molecular distribution (PDI < 1.03) and confirmed the degree of polymerization of mPEG122-b-(PheGE)15. The critical micelle concentration of the copolymer was evaluated using an established fluorescence method with the aggregation behavior evaluated by dynamic light scattering and transmission electronic microscopy...
October 10, 2016: Journal of Visualized Experiments: JoVE
Yu-Zhi Sun, Bo Huang, Wei-Jian Xu, Dong-Dong Zhou, Shao-Li Chen, Shi-Yong Zhang, Zi-Yi Du, Yong-Rong Xie, Chun-Ting He, Wei-Xiong Zhang, Xiao-Ming Chen
Plastic crystals functioning with rotatable components offer new opportunities in areas such as modern optoelectronic materials. Here, by taking advantage of controllable rotation of the polar component within the ion-pair plastic-crystal system, we present two such crystals, namely, (Et4N)(CrO3X) (X = Cl or Br), which are unusual examples exhibiting two-staged thermosensitive dielectric responses above room temperature. The frequency-dependent response in the first stage is due to the structural phase transitions, whereas that in the second stage is induced by dynamic rotation of the polar halochromate anions in their NaCl-type plastic-crystal phases...
October 21, 2016: Inorganic Chemistry
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