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Strong ion difference

Olga Cozzolino, Maria Marchese, Francesco Trovato, Enrico Pracucci, Gian Michele Ratto, Maria Gabriella Buzzi, Federico Sicca, Filippo M Santorelli
Spreading depression (SD) is a neurophysiological phenomenon characterized by abrupt changes in intracellular ion gradients and sustained depolarization of neurons. It leads to loss of electrical activity, changes in the synaptic architecture, and an altered vascular response. Although SD is often described as a unique phenomenon with homogeneous characteristics, it may be strongly affected by the particular triggering event and by genetic background. Furthermore, SD may contribute differently to the pathogenesis of widely heterogeneous clinical conditions...
2018: Frontiers in Neurology
Francesco Di Virgilio, Anna L Giuliani, Valentina Vultaggio-Poma, Simonetta Falzoni, Alba C Sarti
The P2X7 receptor (P2X7R) is a ligand-gated plasma membrane ion channel belonging to the P2X receptor subfamily activated by extracellular nucleotides. General consensus holds that the physiological (and maybe the only) agonist is ATP. However, scattered evidence generated over the last several years suggests that ATP might not be the only agonist, especially at inflammatory sites. Solid data show that NAD + covalently modifies the P2X7R of mouse T lymphocytes, thus lowering the ATP threshold for activation...
2018: Frontiers in Pharmacology
James Dufty, Jeffrey Wrighton
The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations...
January 2018: Physical Review. E
Vincent Desfontaine, Francesca Capetti, Raul Nicoli, Tiia Kuuranne, Jean-Luc Veuthey, Davy Guillarme
Matrix effects (ME) is acknowledged as being one of the major drawbacks of quantitative bioanalytical methods, involving the use of liquid chromatography coupled to mass spectrometry (LC-MS). In the present study, the incidence of ME in SFC-MS/MS and LC-MS/MS in the positive mode electrospray ionization (ESI+) was systematically compared for the analysis of urine and plasma samples using two representative sets of 40 doping agents and 38 pharmaceutical compounds, respectively. Three different SFC stationary phase chemistries were employed, to highlight the importance of the column in terms of selectivity...
February 7, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
H A Alhazmi, M Al Bratty, S A Javed, K G Lalitha
Transferrins (TFs) consist of a large group of glycoproteins, whose function is to transport iron across the cell membrane. Apart from iron, serum transferrin can also bind several other metal ions and hence can offer a potential route for the delivery of these metal ions into the cellular fluids. In the present study the interaction behavior of nine noble metal ions, Ag+, Au+, Au3+, Os3+, Pd2+, Pt4+, Rh3+, Ru3+ and Ir3+ with transferrin was investigated by affinity capillary electrophoresis (ACE) using the dynamic mobility shift mode...
May 1, 2017: Die Pharmazie
Javier E Ortiz, Adriana Garro, Natalia B Pigni, María Belén Agüero, German Roitman, Alberto Slanis, Ricardo D Enriz, Gabriela E Feresin, Jaume Bastida, Alejandro Tapia
BACKGROUND: In Argentina, the Amaryllidaceae family (59 species) comprises a wide variety of genera, only a few species have been investigated as a potential source of cholinesterases inhibitors to treat Alzheimer disease (AD). PURPOSE: To study the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of the basic dichloromethane extracts (E) from Hieronymiella aurea, H. caletensis, H. clidanthoides, H. marginata, and H. speciosa species, as well as the isolated compounds from these plant extracts...
January 15, 2018: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
C Gugliotti, K Moriya, S Tatumi, J Mittani
In the present work, MgO ceramic samples with different terbium concentrations were produced and the Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) properties analyzed and discussed, aiming the use in radiation dosimetry. The samples were produced using MgO, Mg(NO3)2·6H2O, Al2O3, SiO2 and Tb(NO3)3·6H2O precursors in stoichiometric concentrations with five different terbium concentrations between 0.1 and 0.5 mol% and after, heat-treated at high temperature ~1500 °C. X-ray diffraction measurements on samples showed the formation of MgO as principal phase, and others in low concentration due to MgAl2O4, Mg2SiO4 and Tb4O7 phases...
February 3, 2018: Applied Radiation and Isotopes
Nghia Khoi Nguyen, Ulrike Dörfler, Gerhard Welzl, Jean Charles Munch, Reiner Schroll, Marjetka Suhadolc
Glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) have frequently been detected in surface water and groundwaters. Since adequate glyphosate mineralization in soil may reduce its losses to environment, improved understanding of site specific factors underlying pesticide mineralization in soils is needed. The aim of this study was to investigate the relationship between soil properties and glyphosate mineralization. To establish a sound basis for resilient correlations, the study was conducted with a large number of 21 agricultural soils, differing in a variety of soil parameters, such as soil texture, soil organic matter content, pH, exchangeable ions etc...
January 30, 2018: Science of the Total Environment
Xiao-Jing Wang, Yan-Rong Qu, Yong-Liang Zhao, Hai-Bin Chu
Metal-enhanced luminescence of lanthanide complexes by noble metal nanoparticles has attracted much attention because of its high efficiency in improving the luminescent properties of lanthanide ions. Herein, nine kinds of europium and terbium complexes-RE(TPTZ)(ampca)₃·3H₂O, RE(TPTZ)(BA)₃·3H₂O, RE(phen)(ampca)₃·3H₂O, RE(phen)(PTA)1.5·3H₂O (RE = Eu, Tb) and Eu(phen)(BA)₃·3H₂O (TPTZ = 2,4,6-tri(2-pyridyl)-s-triazine, ampca = 3-aminopyrazine-2-carboxylic acid, BA = benzoic acid, phen = 1,10-phenanthroline, PTA = phthalic acid)-have been synthesized...
February 9, 2018: Nanomaterials
Alejandro Ramirez-Solis, Jorge Iván Amaro-Estrada, Jorge Hernández-Cobos, Laurent Maron
We report the results of Born-Oppenheimer molecular dynamics (BOMD) simulations on the aqueous solvation of the SmI3 molecule and of the bare Sm3+ cation at room temperature using the cluster microsolvation approach including 37 and 29 water molecules, respectively. The electronic structure calculations were done using the M062X hybrid exchange-correlation functional in conjunction with the 6-31G** basis sets for oxygen and hydrogen. For the iodine and samarium atoms, the Stuttgart-Köln relativistic effective-core potentials were utilized with their associated valence basis sets...
February 9, 2018: Inorganic Chemistry
Carolina Sánchez-López, Claudio O Fernández, Liliana Quintanar
The cellular prion protein (PrPC) is a copper binding protein that undergoes post-translational modifications, such as endoproteolytic alpha cleavage, which occurs in the vicinity of the His111 Cu binding site. Alpha cleavage processing of PrPC is considered to be neuroprotective since the cleavage site is located in a region that is key to the conversion of PrPC into the infectious scrapie isoform (PrPSc), yielding a membrane bound C1 fragment of PrPC that still contains His111. In this work, we use hPrP(111-115) fragment as a model peptide to evaluate the impact of alpha cleavage processing of PrPC in its ability to coordinate Cu(ii) ions at His111...
February 8, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Yang Wang, Zhong-Ying Ma, De-Long Zhang, Jia-Li Deng, Xiong Chen, Cheng-Zhi Xie, Xin Qiao, Qing-Zhong Li, Jing-Yuan Xu
A new aluminum ion fluorescent probe (4-(diethylamino)-2-hydroxybenzylidene)isoquinoline-1-carbohydrazide (HL1) has been conveniently synthesized and characterized. HL1 exhibited a highly selective and pronounced enhancement for Al3+ in the fluorescence emission over other common cations by forming a 2:1 complex, with a recognition mechanism based on excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT). The strong fluorescent emission can be observed even at ppm level concentration of the probe in the presence of Al3+ with 41 fold intensity enhancement at 545 nm...
January 29, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
F Ehré, C Labbé, C Dufour, W M Jadwisienczak, J Weimmerskirch-Aubatin, X Portier, J-L Doualan, J Cardin, A L Richard, D C Ingram, C Labrugère, F Gourbilleau
Ce-Doped SiOxNy films are deposited by magnetron reactive sputtering from a CeO2 target under a nitrogen reactive gas atmosphere. Visible photoluminescence measurements regarding the nitrogen gas flow reveal a large emission band centered at 450 nm for a sample deposited under a 2 sccm flow. Special attention is paid to the origin of such an emission at high nitrogen concentration. Different emitting centers are suggested in Ce doped SiOxNy films (e.g. band tails, CeO2, Ce clusters, Ce3+ ions), with different activation scenarios to explain the luminescence...
February 7, 2018: Nanoscale
Anne Strate, Viviane Overbeck, Viktoria Lehde, Jan Neumann, Anne-Marie Bonsa, Thomas Niemann, Dietmar Paschek, Dirk Michalik, Ralf Ludwig
Ion pairing is one of the most fundamental atomic interactions in chemistry and biology. In contrast, pairing between like-charged ions remains an elusive concept. So far, this phenomenon was observed only for large-scaled structures, assemblies, stabilizing frameworks, or in aqueous solution wherein like-charge attraction is supported by mediating water molecules. Recently, we reported the formation of cationic clusters in pure ionic liquids (ILs) which all include hydroxyl groups (OH) for possible hydrogen bonding...
February 7, 2018: Physical Chemistry Chemical Physics: PCCP
Sebastian Dillinger, Matthias P Klein, Annika Steiner, David C McDonald, Michael A Duncan, Manfred M Kappes, Gereon Niedner-Schatteburg
We present the cryo IR-PD spectra of the coadsorbed [Ru8(H2)1(N2)4]+ and [Ru8(N2)4(H2)1]+ species differing in the adsorption sequence of H2 and N2, which we record via application of tandem cryo ion trapping. We observe strong evidence for dissociative H2 adsorption and the spectra reveal differences in the Ru-H stretching region, which we assign to distal and proximal hydrogen atom locations on the Ru8+ cluster, their migration likely hindered by preloaded nitrogen molecules, and unaffected by subsequent N2 adsorption...
February 6, 2018: Journal of Physical Chemistry Letters
Nihit Pokhrel, Lutz Maibaum
Understanding how different classes of molecules move across biological membranes is a prerequisite to predicting a solute's permeation rate, which is a critical factor in the fields of drug design and pharmacology. We use biased Molecular Dynamics computer simulations to calculate and compare the free energy profiles of translocation of several small molecules across 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid bilayers as a first step towards determining the most efficient method for free energy calculations...
February 6, 2018: Journal of Chemical Theory and Computation
Patrick Dillane, Lea Krump, Aideen Kennedy, Ríona G Sayers, Gearóid P Sayers
Calf mortality and morbidity commonly occurs within the first month of life postpartum. Standard health ranges are invaluable aids in diagnostic veterinary medicine to confirm normal or the degree and nature of abnormal parameters in (sub)clinically ill animals. Extensive research has indicated significant differences between the physiologies of neonate and adult cattle, particularly for blood parameters such as pH, base excess, anion gap, and bicarbonate (HCO3-). The objective of this research was to determine the influence of age, sex, and breed type, in addition to environmental factors, on the normal blood gas profiles of neonatal calves, and thus develop a scientifically validated reference range accounting for any significant factors...
February 2, 2018: Journal of Dairy Science
Johanna Klyne, Aude Bouchet, Shun-Ichi Ishiuchi, Masaaki Fujii, Otto Dopfer
Consolidated knowledge of conformation and stability of amino acids and their clusters is required to understand their biochemical recognition. Often, alkali ions interact with amino acids and proteins. Herein, infrared photodissociation (IRPD) spectra of cryogenic metalated glutamic acid ions (GluM+, M=Li-Cs) are systematically analyzed in the isomer-specific fingerprint and XH stretch ranges (1100-1900, 2600-3600 cm-1) to provide a direct measure for cation-size dependent conformational locking. GluM+ ions are generated by electrospray ionization and cooled down to 15 K in a cryogenic quadrupole ion trap...
February 2, 2018: Journal of Physical Chemistry. B
Jing Xu, Yu Zhou, Geng Deng, Hamad Ashraf, Zhi-Wu Yu
To elucidate the nature of noncovalent interactions between ionic liquids (ILs) and halogenated molecules is of particular importance for both fundamental research and drug development. In this work, the noncovalent interactions between 1-butyl-3-methyl-imidazolium acetate and three halobenzenes C6F5X (X=I, Br, H) were investigated. The iodine derivative shows the strongest interaction with the IL, followed by C6F5Br and C6F5H. Indicated by the positive/negative peaks and "multi/two-state" phenomena in excess infrared spectra, combined with DFT calculations, various interaction modes were differentiated...
February 1, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
C K Tsui, J A Boedo, P C Stangeby
A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter lp, and the model is thus referred to as the "perimeter sheath expansion method...
January 2018: Review of Scientific Instruments
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