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https://www.readbyqxmd.com/read/27913957/chemical-characterization-of-rainwater-at-a-high-altitude-site-nainital-in-the-central-himalayas-india
#1
Deewan Singh Bisht, A K Srivastava, H Joshi, K Ram, N Singh, M Naja, M K Srivastava, S Tiwari
The present study investigates the chemical composition of rainwater (RW) from a high-altitude site "Nainital" (1958 m above msl) in the central Himalaya region, to understand the influence of local, regional, and long-range transport of pollutants. A total of 55 (2 in pre-monsoon and 53 in monsoon) RW samples were collected during the study period (June-September 2012) and were analyzed for major anions and cations using an ion chromatograph. The pH of precipitation events ranged from 4.95 to 6.50 (average 5...
December 2, 2016: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/27913928/coordination-complexes-of-4-methylimidazole-with-zn-ii-and-cu-ii-in-gas-phase-and-in-water-a-dft-study
#2
Malek Boukallaba, Boutheïna Kerkeni, Christine Lepetit, Dorothée Berthomieu
A quantum chemistry study of mononuclear metal coordination with four 4-methylimidazole ligands (4-MeIm) was investigated. The four complexes [Cu(4-MeIm)4](2+), [Cu(4-MeIm)4, H2O](2+), [Zn(4-MeIm)4](2+) and [Zn(4-MeIm)4, H2O](2+) were studied with particular attention to the Nπ or Nτ possible coordinations of the 4-MeIm ring with the metals, using different DFT methods. The results suggest that the Nτ coordination of 4-MeIm ring to Zn(II) or Cu(II) is more favorable whatever the level of calculation. In contrast, the addition of one water molecule in the first coordination sphere of the metal ions provides five-coordinated complexes showing no Nπ or Nτ preferences...
December 2016: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/27907144/a-new-efficient-method-for-detecting-phase-singularity-in-cardiac-fibrillation
#3
Young-Seon Lee, Jun-Seop Song, Minki Hwang, Byounghyun Lim, Boyoung Joung, Hui-Nam Pak
BACKGROUND: The point of phase singularity (PS) is considered to represent a spiral wave core or a rotor in cardiac fibrillation. Computational efficiency is important for detection of PS in clinical electrophysiology. We developed a novel algorithm for highly efficient and robust detection of PS. METHODS: In contrast to the conventional method, which calculates PS based on the line integral of the phase around a PS point equal to ±2π (the Iyer-Gray method), the proposed algorithm (the location-centric method) looks for the phase discontinuity point at which PS actually occurs...
2016: PloS One
https://www.readbyqxmd.com/read/27884530/heteroaggregation-of-graphene-oxide-nanoparticles-and-kaolinite-colloids
#4
Nikolaos P Sotirelis, Constantinos V Chrysikopoulos
Graphene oxide (GO) is a material with rapid production growth, and consequently GO nanoparticles are expected to eventually penetrate subsurface formations, where fine mineral particles are in abundance. This study examines the heteroaggregation of GO nanoparticles with kaolinite (KGa-1b) colloids under various conditions. Dynamic batch experiments were conducted in solutions with different pH values (pH=4, 7, and 10), different ionic strengths (IS=7, 12, and 27mM), and at three controlled temperatures (8, 14, and 25°C)...
November 22, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27880924/pb-2-ions-mobility-perturbation-by-iron-particles-during-electrokinetic-remediation-of-contaminated-soil
#5
Waqas Zulfiqar, Muhammad Asad Iqbal, Mehwish Khalid Butt
Electrokinetic (EK) remediation is one of the most useful approaches for de-contamination of soils. However, it is unclear that how and when the electrokinetic remediation gives advantages over other remediation techniques in soil. This study was designed to find the influence of Fe(2+) particles on the mobility of Pb(2+) ions, during electrokinetic remediation, in soil contaminated purposely by lead nitrate Pb(NO3)2. Two types of electrokinetic experiments were performed, by using iron and graphite electrodes...
November 20, 2016: Chemosphere
https://www.readbyqxmd.com/read/27878040/effect-of-contrast-media-on-urinary-cytopathology-specimens
#6
Sebastian Frees, Samir Bidnur, Michael Metcalfe, Peter Raven, Claudia Chavez-Munoz, Igor Moskalev, Ladan Fazli, Alan So
INTRODUCTION: Urological dogma dictates that washings collected from the urinary tract for cytological assessment must be performed without interference from contrast agents that may alter cellular integrity and diagnostic interpretation. In practice, the initial contrast used to outline the upper tracts is commonly discarded with subsequent saline washings sent for cytology. We hypothesize that contrast washings do not affect the morphology of urothelial carcinoma cells or the integrity of cytology interpretation...
August 2016: Canadian Urological Association Journal, Journal de L'Association des Urologues du Canada
https://www.readbyqxmd.com/read/27877155/weak-and-saturable-protein-surfactant-interactions-in-the-denaturation-of-apo-%C3%AE-lactalbumin-by-acidic-and-lactonic-sophorolipid
#7
Kell K Andersen, Brian S Vad, Sophie Roelants, Inge N A van Bogaert, Daniel E Otzen
Biosurfactants are of growing interest as sustainable alternatives to fossil-fuel-derived chemical surfactants, particularly for the detergent industry. To realize this potential, it is necessary to understand how they affect proteins which they may encounter in their applications. However, knowledge of such interactions is limited. Here, we present a study of the interactions between the model protein apo-α-lactalbumin (apo-aLA) and the biosurfactant sophorolipid (SL) produced by the yeast Starmerella bombicola...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27870135/independent-assessment-of-matrix-assisted-laser-desorption-ionization-mass-spectrometry-maldi-ms-sample-preparation-quality-effect-of-sample-preparation-on-maldi-ms-of-synthetic-polymers
#8
Pieter C Kooijman, Sander Kok, Maarten Honing
RATIONALE: Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) provides detailed and in-depth information about the molecular characteristics of synthetic polymers. To obtain the most accurate results the sample preparation parameters should be chosen to suit the sample and the aim of the experiment. Because the underlying principles of MALDI are still not fully known, a priori determination of optimal sample preparation protocols is often not possible. METHODS: Employing an automated sample preparation quality assessment method recently presented by us we quantified the sample preparation quality obtained using various sample preparation protocols...
November 21, 2016: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/27869282/adsorption-and-desorption-behavior-of-ionic-and-nonionic-surfactants-on-polymer-surfaces
#9
Giulia Magi Meconi, Nicholas Ballard, José M Asua, Ronen Zangi
We report combined experimental and computational studies aiming to elucidate the adsorption properties of ionic and nonionic surfactants on hydrophobic polymer surface such as poly(styrene). To represent these two types of surfactants, we choose sodium dodecyl sulfate and poly(ethylene glycol)-poly(ethylene) block copolymers, both commonly utilized in emulsion polymerization. By applying quartz crystal microbalance with dissipation monitoring we find that the non-ionic surfactants are desorbed from the poly(styrene) surface slower, and at low surfactant concentrations they adsorb with stronger energy, than the ionic surfactant...
November 21, 2016: Soft Matter
https://www.readbyqxmd.com/read/27868467/k-channel-reorganization-and-homeostatic-plasticity-during-postembryonic-development-biophysical-and-genetic-analyses-in-acutely-dissociated-drosophila-central-neurons
#10
Taixiang Saur, I-Feng Peng, Peng Jiang, Neng Gong, Wei-Dong Yao, Tian-Le Xu, Chun-Fang Wu
Intrinsic electric activities of neurons play important roles in establishing and refining neural circuits during development. However, how the underlying ionic currents undergo postembryonic reorganizations remains largely unknown. Using acutely dissociated neurons from larval, pupal, and adult Drosophila brains, we show drastic re-assemblies and compensatory regulations of voltage-gated (IKv) and Ca(2+)-activated (IK(Ca)) K(+ )currents during postembryonic development. Larval and adult neurons displayed prominent fast-inactivating IKv, mediated by the Shaker (Sh) channel to a large extent, while in the same neurons IK(Ca) was far smaller in amplitude...
November 21, 2016: Journal of Neurogenetics
https://www.readbyqxmd.com/read/27863354/contrast-media-use-in-patients-with-chronic-kidney-disease-undergoing-coronary-angiography-a-systematic-review-and-meta-analysis-of-randomized-trials
#11
Bhavi Pandya, Jean Chaloub, Valay Parikh, Sainath Gaddam, Jonathan Spagnola, Suzanne El-Sayegh, Marc Bogin, Ruben Kandov, James Lafferty, Sripal Bangalore
BACKGROUND: Patients with chronic kidney disease (CKD) undergoing coronary angiography (CA), adequate hydration and minimizing volume of contrast media (CM) are class 1b recommendations for preventing contrast induced nephropathy (CIN). Current data are insufficient to justify specific recommendations about isoosmolar vs. low-osmolar contrast media by the ACCF/AHA/SCAI guidelines. METHODS: Randomized trials comparing IOCM to LOCM in CKD stage 3 and above patients undergoing CA, and reporting incidence of CIN (defined by a rise in creatinine of 25% from baseline) were included in the analysis...
November 9, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/27853207/implications-for-metal-and-volatile-cycles-from-the-ph-of-subduction-zone-fluids
#12
Matthieu E Galvez, James A D Connolly, Craig E Manning
The chemistry of aqueous fluids controls the transport and exchange-the cycles-of metals and volatile elements on Earth. Subduction zones, where oceanic plates sink into the Earth's interior, are the most important geodynamic setting for this fluid-mediated chemical exchange. Characterizing the ionic speciation and pH of fluids equilibrated with rocks at subduction zone conditions has long been a major challenge in Earth science. Here we report thermodynamic predictions of fluid-rock equilibria that tie together models of the thermal structure, mineralogy and fluid speciation of subduction zones...
November 16, 2016: Nature
https://www.readbyqxmd.com/read/27846698/evaluation-of-effects-of-ph-and-ionic-strength-on-colloidal-stability-of-igg-solutions-by-peg-induced-liquid-liquid-phase-separation
#13
Ronald W Thompson, Ramil F Latypov, Ying Wang, Aleksey Lomakin, Julie A Meyer, Suresh Vunnum, George B Benedek
Colloidal stability of IgG antibody solutions is important for pharmaceutical and medicinal applications. Solution pH and ionic strength are two key factors that affect the colloidal stability of protein solutions. In this work, we use a method based on the PEG-induced liquid-liquid phase separation to examine the effects of pH and ionic strength on the colloidal stability of IgG solutions. We found that at high ionic strength (≥0.25M), the colloidal stability of most of our IgGs is insensitive to pH, and at low ionic strength (≤0...
November 14, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27836634/visualization-of-aspergillus-fumigatus-biofilms-with-scanning-electron-microscopy-and-variable-pressure-scanning-electron-microscopy-a-comparison-of-processing-techniques
#14
Lydia-Marie Joubert, Jose Ag Ferreira, David A Stevens, Hasan Nazik, Lynette Cegelski
Aspergillus fumigatus biofilms consist of a three-dimensional network of cellular hyphae and extracellular matrix. They are involved in infections of immune-compromised individuals, particularly those with cystic fibrosis. These structures are associated with persistence of infection, resistance to host immunity, and antimicrobial resistance. Thorough understanding of structure and function is imperative in the design of therapeutic drugs. Optimization of processing parameters, including aldehyde fixation, heavy metal contrasting, drying techniques and Ionic Liquid treatment, was undertaken for an ultrastructural approach to understand cellular and extracellular biofilm components...
November 9, 2016: Journal of Microbiological Methods
https://www.readbyqxmd.com/read/27828553/simulations-of-the-water-exchange-dynamics-of-lanthanide-ions-in-1-ethyl-3-methylimidazolium-ethyl-sulfate-emim-etso4-and-water
#15
Yi-Jung Tu, Matthew J Allen, G Andrés Cisneros
The dynamics of ligand exchange on lanthanide ions is important for catalysis and organic reactions. Recent (17)O-NMR experiments have shown that water-exchange rates of lanthanide ions in water/1-ethyl-3-methylimidazolium ethyl sulfate (water/[EMIm][EtSO4]) increase as a function of increasing charge density. The trend of water-exchange rates in this solvent is opposite to that observed in water. Since the lanthanide ions and ionic liquids investigated in that work were highly charged, an advanced polarizable potential is desirable for accurate simulations...
November 9, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27826994/diagnostic-efficacy-of-single-pass-abdominal-multidetector-row-ct-prospective-evaluation-of-a-low-dose-protocol
#16
Luigi Camera, Immacolata Liccardo, Federica Romano, Raffaele Liuzzi, Antonio Rispo, Massimo Imbriaco, Anna Testa, Gaetano Luglio, Simona De Fronzo, Fabiana Castiglione, Luigi Bucci, Arturo Brunetti
OBJECTIVES: To evaluate the diagnostic efficacy of single-pass contrast-enhanced multi-detector CT (CE-MDCT) performed with a low radiation-high contrast (LR-HC) dose protocol in selected patients with non traumatic acute bowel disease. METHODS: Sixty-five (32 M; 33 F; aged 20-67 years) consecutive patients with non traumatic acute bowel disease underwent single-pass CE-MDCT performed 70-100 sec after i.v. bolus injection of a non ionic iodinated contrast media (370 mgI/ml)...
November 9, 2016: British Journal of Radiology
https://www.readbyqxmd.com/read/27819378/strings-and-stripes-formed-by-a-protein-system-interacting-via-a-single-patch-attraction
#17
Weimin Li, Maxim Morin, Emil Gustafsson, Björn A Persson, Mikael Lund, Malin Zackrisson Oskolkova
The phase behavior of lactoferrin has been studied as a function of concentration at a pH and ionic strength where lactoferrin is known to interact effectively via a patch-patch attraction. In contrast to isotropic attractive potentials, the directional attraction gives rise to a different phase or solution behavior. At low concentrations, the protein dimerizes. As the concentration is increased, the protein self-assembles into elongated, stripe-like structures at intermediate protein concentrations, a behavior which has been predicted for the case of attractive one-patch colloids...
November 7, 2016: Soft Matter
https://www.readbyqxmd.com/read/27809540/chemisorption-of-hydroxide-on-2d-materials-from-dft-calculations-graphene-versus-hexagonal-boron-nitride
#18
Benoit Grosjean, Clarisse Péan, Alessandro Siria, Lyderic Bocquet, Rodolphe Vuilleumier, Marie-Laure Bocquet
Recent nanofluidic measurements revealed strongly different surface charge mea- surements for boron-nitride and graphitic nanotubes when in contact with saline and alkaline water.1,2 These observations contrast with the similar reactivity of a graphene layer and its boron nitride counterpart, using Density Functional Theory (DFT) frame- work, for intact and dissociative adsorption of gaseous water molecules. Here, we in- vestigate by DFT in implicit water single and multiple adsorption of anionic hydroxide on single layers...
November 3, 2016: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/27805236/selective-complexation-of-divalent-cations-by-a-cyclic-%C3%AE-%C3%AE-peptoid-hexamer-a-spectroscopic-and-computational-study
#19
E De Santis, A A Edwards, B D Alexander, S J Holder, A-S Biesse-Martin, B V Nielsen, D Mistry, L Waters, G Siligardi, R Hussain, S Faure, C Taillefumier
We describe the qualitative and quantitative analysis of the complexation properties towards cations of a cyclic peptoid hexamer composed of alternating α- and β-peptoid monomers, which bear exclusively chiral (S)-phenylethyl side chains (spe) that have no noticeable chelating properties. The binding of a series of monovalent and divalent cations was assessed by (1)H NMR, circular dichroism, fluorescence and molecular modelling. In contrast to previous studies on cations binding by 18-membered α-cyclopeptoid hexamers, the 21-membered cyclopeptoid cP1 did not complex monovalent cations (Na(+), K(+), Ag(+)) but showed selectivity for divalent cations (Ca(2+), Ba(2+), Sr(2+) and Mg(2+))...
November 2, 2016: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/27796332/smooth-deuterated-cellulose-films-for-the-visualisation-of-adsorbed-bio-macromolecules
#20
Jielong Su, Vikram S Raghuwanshi, Warwick Raverty, Christopher J Garvey, Peter J Holden, Marie Gillon, Stephen A Holt, Rico Tabor, Warren Batchelor, Gil Garnier
Novel thin and smooth deuterated cellulose films were synthesised to visualize adsorbed bio-macromolecules using contrast variation neutron reflectivity (NR) measurements. Incorporation of varying degrees of deuteration into cellulose was achieved by growing Gluconacetobacter xylinus in deuterated glycerol as carbon source dissolved in growth media containing D2O. The derivative of deuterated cellulose was prepared by trimethylsilylation(TMS) in ionic liquid(1-butyl-3-methylimidazolium chloride). The TMS derivative was dissolved in toluene for thin film preparation by spin-coating...
October 31, 2016: Scientific Reports
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