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https://www.readbyqxmd.com/read/28435968/unexpected-proton-mobility-in-the-bulk-phase-of-cholinium-based-ionic-liquids-new-insights-from-theoretical-calculations
#1
Marco Campetella, Maria Montagna, Lorenzo Gontrani, Eleonora Scarpellini, Enrico Bodo
We have explored by means of ab initio molecular dynamics two ionic liquids based on the combination of a choline cation with deprotonated cysteine and aspartic acid anions. While the combination of the strong base choline with various other amino-acids leads to the formation of a highly ionized medium where proton transfer is negligible, the presence of additional protic functions on the SH and COOH groups leads to an unexpected and interesting behavior and to a sizable migration of their acidic protons onto the NH2 basic terminals...
April 24, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28434232/modeling-bi-solute-adsorption-of-aromatic-compounds-based-on-adsorbed-solution-theories-asts
#2
Huichun Zhang, Shubo Wang
A large number of organic contaminants are commonly found in industrial and municipal wastewaters. For proper unit design to remove contaminant mixtures by adsorption, multi-component adsorption equilibrium models are necessary. The present work examined the applicability of Ideal Adsorbed Solution Theory (IAST), a prevailing thermodynamic model, and its derivatives, i.e., Segregated IAST (SIAST) and Real Adsorbed Solution Theory (RAST), to bi-solute adsorption of organic compounds onto a hyper-crosslinked polystyrene resin, MN200...
April 24, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28433954/lipidomic-profile-in-three-species-of-dinoflagellates-amphidinium-carterae-cystodinium-sp-and-peridinium-aciculiferum-containing-very-long-chain-polyunsaturated-fatty-acids
#3
Tomáš Řezanka, Jaromír Lukavský, Linda Nedbalová, Karel Sigler
This study describes the identification of very long chain polyunsaturated fatty acids (VLCPUFAs) in three strains of dinoflagellates (Amphidinium carterae, Cystodinium sp., and Peridinium aciculiferum). The strains were cultivated and their lipidomic profiles were obtained by high resolution mass spectrometry with the aid of positive and negative electrospray ionization (ESI) mode by Orbitrap apparatus. Hydrophilic interaction liquid chromatography (HILIC/ESI) was used to separate major lipid classes of the three genera of dinoflagellates by neutral loss scan showing the ion [M + H-28:8](+), where 28:8 was octacosaoctaenoic acid, and by precursor ion scanning of ions at m/z 407, which was an ion corresponding to the structure of acyl of 28:8 acid (C27H39COO(-))...
April 20, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28433435/fabric-phase-sorptive-extraction-as-a-reliable-tool-for-rapid-screening-and-detection-of-freshness-markers-in-oranges
#4
M Aznar, S Úbeda, C Nerin, A Kabir, K G Furton
A simple, fast and sensitive analyte extraction method based on fabric phase sorptive extraction (FPSE) followed by gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF-MS) analysis was developed for the analysis of 12 volatile compounds that represent most of the principal chemical families possessing different polarities and volatilities. Five FPSE media coated with different sol-gel sorbent chemistries having different polarities and selectivities were studied: long chain poly(dimethylsiloxane) (PDMS), short chain poly(tetrahydrofuran) (PTHF), Carbowax 20M (CW20M), short chain poly(dimethyl siloxane) (SC PDMS) and polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer (PEG-PPG-PEG)...
April 8, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28433034/direct-1-h-nmr-evidence-of-spin-rotation-coupling-as-a-source-of-para-%C3%A2-ortho-h2-conversion-in-diamagnetic-solvents
#5
Camilla Terenzi, Sabine Bouguet-Bonnet, Daniel Canet
At ambient temperature, conversion from 100% enriched para-hydrogen (p-H2; singlet state) to ortho-hydrogen (o-H2; triplet state) leads necessarily to the thermodynamic equilibrium proportions: 75% of o-H2 and 25% of p-H2. When p-H2 is dissolved in a diamagnetic organic solvent, conversion is very slow and can be considered as arising from nuclear spin relaxation phenomena. A first relaxation mechanism, specific to the singlet state and involving a combination of auto-correlation and cross correlation spectral densities, can be retained: randomly fluctuating magnetic fields due to inter-molecular dipolar interactions...
April 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28432991/characteristics-of-adapted-hydrogenotrophic-community-during-biomethanation
#6
Lydia Rachbauer, Reinhard Beyer, Günther Bochmann, Werner Fuchs
The results presented in this study were carried out as concomitant experiments during the start-up and operation of a biomethanation unit to evaluate the effect of process parameters on carbon conversion, product formation (methane and acetate) and community composition. For that, two different samples were withdrawn from a trickle-bed reactor with immobilized enrichment culture of hydrogenotrophic methanogens adapted from sewage sludge. One sample was taken from the recirculation liquid during start-up phase while the other was withdrawn directly from the carrier material in the reactor...
April 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28432955/the-calorimetric-properties-of-liposomes-determine-the-morphology-of-dried-droplets
#7
Jorge González-Gutiérrez, Rosendo Pérez-Isidoro, M I Pérez-Camacho, J C Ruiz-Suárez
The evaporation of liquid droplets deposited on a substrate is a very complex phenomenon. Driven by capillary and Marangoni flows, particle-particle and particle-substrate interactions, the deposits they leave are vestiges of such complexity. We study the formation of patterns during the evaporation of liposome suspension droplets deposited on a hydrophobic substrate at different temperatures. We observed that as we change the temperature of the substrate, a morphological phase transition occurs at a given temperature Tm...
April 19, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28431687/a-rapid-impregnation-method-for-loading-desired-amounts-of-extractant-on-prepacked-reversed-phase-columns-for-high-performance-liquid-chromatographic-separation-of-metal-ions
#8
Muhammad Ramzan, Dejene Kifle, Grethe Wibetoe
A time-efficient impregnation method for loading extractant onto reversed-phase columns was developed, using di-(2-ethylhexyl) phosphoric acid (HDEHP) as a model extractant. The optimal loading conditions for the impregnation process of a standard analytical scale column was achieved by dissolving an appropriate amount of HDEHP (per void volume) in n-pentane, flushing the column with two void volumes (5mL) of impregnation solution and heating the column for a short time to remove the solvent. The process takes about one hour, a significant time reduction compared to commonly used impregnation methods (17-23h)...
April 7, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28430148/a-rapid-magnetic-solid-phase-extraction-method-followed-by-liquid-chromatography-tandem-mass-spectrometry-analysis-for-the-determination-of-mycotoxins-in-cereals
#9
Giorgia La Barbera, Anna Laura Capriotti, Chiara Cavaliere, Patrizia Foglia, Carmela Maria Montone, Riccardo Zenezini Chiozzi, Aldo Laganà
Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone...
April 21, 2017: Toxins
https://www.readbyqxmd.com/read/28427044/on-the-reverse-micelle-effect-in-liquid-scintillation-counting
#10
Youcef Nedjadi, Jean-Pascal Laedermann, François Bochud, Claude Bailat
This work looks into the tracks of electrons in nanoemulsive scintillating media using the Monte Carlo Geant4-DNA code which simulates event-by-event interactions of electrons in liquid water down to the eV, without resorting to the condensed history method. It demonstrates that the average number of micelles in which electrons deposit energy is quite large, increasing with their emission energy, decreasing with micelle size, and rising with micelle concentration. The probability of an electron ending its track in a micelle is found to be rather large and micelle size-dependent below 1keV, and approximating the aqueous fraction at higher energies...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28426156/natural-terpene-derivatives-as-new-structural-task-specific-ionic-liquids-to-enhance-the-enantiorecognition-of-acidic-enantiomers-on-teicoplanin-based-stationary-phase-by-high-performance-liquid-chromatography
#11
Jolanta Flieger, Joanna Feder-Kubis, Małgorzata Tatarczak-Michalewska, Anita Płazińska, Anna Madejska, Marta Swatko-Ossor
We present the specific cooperative effect of a semisynthetic glycopeptide antibiotic teicoplanin and chiral ionic liquids containing the (1R,2S,5R)-(-)-menthol moiety on the chiral recognition of enantiomers of mandelic acid, vanilmandelic acid and phenyllactic acid. Experiments were performed chromatographically on an Astec Chirobiotic T chiral stationary phase applying the mobile phase with the addition of the chiral ionic liquids. The stereoselective binding of enantiomers to teicoplanin in presence of new chiral ionic liquids were evaluated applying thermodynamic measurements and the docking simulations...
April 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28425554/on-the-parallelism-between-the-mechanisms-behind-chromatography-and-drug-delivery-the-role-of-interactions-with-a-stationary-phase
#12
Filippo Rossi, Franca Castiglione, Matteo Salvalaglio, Monica Ferro, Marta Moioli, Emanuele Mauri, Maurizio Masi, Andrea Mele
A huge number of studies and work in the drug delivery literature are focused on understanding and modeling transport phenomena, the pivotal point for a good device design. The rationalization of all phenomena involved is fundamental, but several concerns arise leaving many issues unsolved. In order to change the point of view we decided to focus our attention on the parallelisms between two fields that seem to be very far from each other: chromatography and drug release. Taking advantages of the studies conducted by many researchers using chromatographic columns we decided to explain all the phenomena involved in drug delivery considering sodium ibuprofen (IP) molecules as analytes and hydrogel as a stationary phase...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28425188/effects-of-age-and-viscosity-on-food-transport-and-breathing-swallowing-coordination-during-eating-of-two-phase-food-in-nursing-home-residents
#13
Tsuyoshi Yamada, Koichiro Matsuo, Masayuki Izawa, Shizuru Yamada, Yuji Masuda, Tadashi Ogasawara
AIM: When eating food that contains both liquid and solid phases, the liquid component frequently enters the hypopharynx before swallowing and can increase the risk of aspiration. Thus, we examined whether the initial viscosity of mixed consistency food could alter pre-swallow food transport and breathing-swallowing coordination in older adults. METHODS: Fiberoptic endoscopy was recorded while 18 healthy young adults and 19 older adults ate 5 g of steamed rice combined with 3 mL of blue-dye water...
April 20, 2017: Geriatrics & Gerontology International
https://www.readbyqxmd.com/read/28422657/phased-array-ultrasound-system-for-planar-flow-mapping-in-liquid-metals
#14
Kevin Mader, Richard Nauber, Vladimir Galindo, Hannes Beyer, Lars Buttner, Sven Eckert, Jurgen Czarske
Controllable magnetic fields can be used to optimize flows in technical and industrial processes involving liquid metals in order to improve quality and yield. However, experimental studies in magnetohydrodynamics (MHD) often involve complex, turbulent flows and require planar, two-component velocity measurements through only one acoustical access. We present the phased array ultrasound Doppler velocimeter (PAUDV) as a modular research platform for flow mapping in liquid metals. It combines the pulse wave Doppler method with the phased array technique to adaptively focus the ultrasound beam...
April 12, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28422219/a-nematic-to-nematic-transformation-exhibited-by-a-rod-like-liquid-crystal
#15
Richard J Mandle, S J Cowling, J W Goodby
A novel, highly polar rod-like liquid crystal was found to exhibit two distinct nematic mesophases (N and NX). When studied by microscopy and X-ray scattering experiments, and under applied electric fields, the nematic phases are practically identical. However, calorimetry experiments refute the possibility of an intervening smectic mesophase, and the transformation between the nematic phases was associated with a weak thermal event. Analysis of measured dielectric data, along with molecular properties obtained from DFT calculations, applying the Maier-Meier relationship allowed for the degree of antiparallel pairing of dipoles in both nematic phases to be quantified...
April 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28419580/liquid-liquid-interfacial-synthesis-of-click-nanosheet
#16
Amalia Rapakousiou, Ryo Shiotsuki, Ryota Sakamoto, Ryota Matsuoka, Ukyo Nakajima, Tigmansu Pal, Rintaro Shimada, Md Amran Hossain, Hiroyasu Masunaga, Satoshi Horike, Yasutaka Kitagawa, Sono Sasaki, Kenichi Kato, Takeaki Ozawa, Didier Astruc, Hiroshi Nishihara
A liquid/liquid interfacial synthesis is employed for the first time to synthesize a covalent two-dimensional polymer nanosheet. Copper-catalyzed azide-alkyne cycloaddition (CuAAC) between three-way terminal alkyne and azide at a water/dichloromethane interface generates a 1,2,3-triazole-linked nanosheet. The resultant nanosheet with a flat and smooth texture has a maximum domain size of 20 μm and minimum thickness of 5.3 nm. The starting monomers in the organic phase and the copper catalyst in the aqueous phase can meet together only at the liquid/liquid interface as a two-dimensional reaction space, which allows them to form the two-dimensional polymer...
April 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28418683/physical-characterization-of-tobramycin-inhalation-powder-ii-state-diagram-of-an-amorphous-engineered-particle-formulation
#17
Dan Miller, Trixie Tan, John Nakamura, Richard Malcolmson, Tom Tarara, Jeff Weers
Tobramycin Inhalation Powder (TIP) is a spray-dried engineered particle formulation used in TOBI® Podhaler®, a drug/device combination for treatment of cystic fibrosis. A TIP particle consists of two phases: amorphous, glassy tobramycin sulfate and a gel-phase phospholipid (DSPC). The objective of this work was to characterize both the amorphous and gel phases following exposure of TIP to a broad range of relative humidity and temperature. Because, in principle, changes in either particle morphology or the solid-state form of the drug could affect drug delivery or biopharmaceutical properties, understanding physical stability was critical to development and registration of this product...
April 18, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28418274/the-gulf-long-term-follow-up-study-gulf-study-biospecimen-collection-at-enrollment
#18
Lawrence S Engel, Richard K Kwok, Aubrey K Miller, Aaron Blair, Matthew D Curry, John A McGrath, Dale P Sandler, Polly Armsby, Susan Baker, Richard D Cohn, Edward E Gaunt, Audra Hodges, David Johndrow, Steven K Ramsey, Mark Stenzel, Patricia Stewart
The 2010 Deepwater Horizon (DWH) explosion in the Gulf of Mexico led to the largest ever marine oil spill by volume. The GuLF STUDY is investigating possible adverse human health effects associated with oil spill activities. One objective of the study was to utilize biological specimens from study participants to examine spill-related adverse health effects. This study describes the methods for collecting, processing, shipping, and storing specimens during the enrollment phase of the study. GuLF STUDY participants living in Gulf States (Alabama, Florida, Louisiana, Mississippi, and eastern Texas) were eligible to complete a home visit at enrollment, one to three years after the DWH explosion...
April 18, 2017: Journal of Toxicology and Environmental Health. Part A
https://www.readbyqxmd.com/read/28418044/design-of-liquid-crystals-with-de-vries-like-properties-structural-variants-of-carbosilane-terminated-5-phenylpyrimidine-mesogens
#19
Christopher P J Schubert, Carsten Müller, Andreas Bogner, Frank Giesselmann, Robert P Lemieux
Structural variants of the 'de Vries-like' mesogen 5-[4-(12,12,14,14,16,16-hexamethyl-12,14,16-trisilaheptadecyloxy)phenyl]-2-hexyloxypyrimidine (QL16-6), including two isomers with branched iso-tricarbosilane end-groups, were synthesized and their mesomorphic and 'de Vries-like' properties were characterized by polarized optical microscopy, differential scanning calorimetry, small angle and 2D X-ray scattering techniques. A comparative analysis of isomers with linear and branched tricarbosilane end-groups shows that they exhibit comparable mesomorphic and 'de Vries-like' properties...
April 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28416888/tailoring-pore-size-and-chemical-interior-of-near-1-nm-sized-pores-in-a-nanoporous-polymer-based-on-a-discotic-liquid-crystal
#20
Subham Bhattacharjee, Jody A M Lugger, Rint P Sijbesma
A triazine based disc shaped molecule with two hydrolyzable units, imine and ester groups, was polymerized via acyclic diene metathesis in the columnar hexagonal (Colhex) LC phase. Fabrication of a cationic nanoporous polymer (pore diameter ∼1.3 nm) lined with ammonium groups at the pore surface was achieved by hydrolysis of the imine linkage. Size selective aldehyde uptake by the cationic porous polymer was demonstrated. The anilinium groups in the pores were converted to azide as well as phenyl groups by further chemical treatment, leading to porous polymers with neutral functional groups in the pores...
April 11, 2017: Macromolecules
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