Search results for "Quaternary"
showing 10 items of 411 documents
Hypoosmolar conditions reduce extracellular volume fraction and enhance epileptiform activity in the CA3 region of the immature rat hippocampus
2006
The osmolarity of the extracellular space (ECS) compartment is an important factor determining the excitability of neuronal tissue. In the adult hippocampus an important role of osmolarity and ECS diffusion parameters on the susceptibility to epileptic events is well established, but the influence of hypo- and hyperosmolar conditions on the immature hippocampus remains elusive. To investigate the influence of osmolarity on epileptiform activity, extracellular field potentials were recorded in the CA3 region of hippocampal slices of immature (postnatal days 4-7) Wistar rats. The ECS diffusion parameters were determined by the real-time tetramethylammonium (TMA+) iontophoretic method with ion…
The effect of immersion disinfection procedures on dimensional stability of two elastomeric impression materials
2008
The aim of this study was to determine the effect of immersion disinfection procedures on the dimensional stability of two elastomeric impression materials. Impressions of a stainless steel die were made with polyether (PE) and with additionpolymerized silicone rubber (PVS). The test specimens underwent disinfection treatment by immersion in two commercially available solutions containing quaternary ammonium compounds (Sterigum Powder, SP) and glutaraldehyde plus an amino derivative (MD520, MD), respectively. The impressions were measured at 4 different time points: before any disinfection treatment (T0); after the first disinfection (T1); 6 hours after the first disinfection (T2); after th…
The role of in situ species diversification for the evolution of high vascular plant species diversity in the European Alps—A review and interpretati…
2017
Abstract By harbouring ca. 3500 native vascular plant species in an area of ca. 170 000 km2, the European Alps represent a region of very high species diversity. Using the most recently published flora of the area and phylogenetic literature, I here review which proportion of the endemic flora of the Alps is the result of in situ diversification, i.e., of diversification in the area and (largely) restricted to the area. There exist only very few and mostly species-poor species diversifications in the Alps, accounting for ca. 1.2% of the native and for ca. 9% of the endemic flora of the Alps. In contrast to this, ca. 33% of the endemic species of the Alps belong to lineages widespread in the…
Toward Quaternary QCA : Novel Majority and XOR Fuzzy Gates
2022
As an emerging nanotechnology, quantum-dot cellular automata (QCA) has been considered an alternative to CMOS technology that suffers from problems such as leakage current. Moreover, QCA is suitable for multi-valued logic due to the simplicity of implementing fuzzy logic in a way much easier than CMOS technology. In this paper, a quaternary cell is proposed with two isolated layers because of requiring three particles to design this quaternary cell. Moreover, due to the instability of the basic gates, the three particles cannot be placed in one layer. The first layer of the proposed two-layer cell includes a ternary cell and the second one includes a binary cell. It is assumed that the over…
Sequestration of biogenic amines by alginic and fulvic acids.
2006
The interaction of natural (alginic and fulvic acids) and synthetic (polyacrylic acid 2.0 kDa) polyelectrolytes with some protonated polyamines [diamines: ethylendiamine, 1,4-diaminobutane (or putrescine), 1,5-diaminopentane (or cadaverine); triamines: N-(3-aminopropyl)-1,4diaminobutane (or spermidine), diethylenetriamine; tetramine: N.N'-bis(3-aminopropyl)-1,4-diaminobutane (or spermine); pentamine: tetraethylene-pentamine; hexamine: pentaethylenehexamine] was studied at T=25 degrees C by potentiometry and calorimetry. Measurements were performed without supporting electrolyte, in order to avoid interference, and results were reported at I=0 mol L(-1). For all the systems, the formation of…
N,N-Dimethyl-N-propylpropan-1-aminium chloride monohydrate
2008
The title compound, C8H20N+·Cl−·H2O, has been prepared by a simple one-pot synthesis route followed by anion exchange using resin. In the crystal structure, the cations are packed in such a way that channels exist parallel to the b axis. These channels are filled by the anions and water molecules, which interact via O—H...Cl hydrogen bonds [O...Cl = 3.285 (3) and 3.239 (3) Å] to form helical chains. The cations are involved in weak intermolecular C—H...Cl and C—H...O hydrogen bonds. The title compound is not isomorphous with the bromo or iodo analogues.
Submarine Slope Failures Along the Northern Sicilian Continental Margin (Southern Tyrrhenian Sea) and Possible Implications for Geo-Hazard
2013
Mass wasting and downslope movements are common processes that have contributed to shape the northern Sicilian continental margin (southern Tyrrhenian Sea) since the Late Quaternary. Nevertheless, processes controlling their evolution are still partially unknown and a variety of geologic factors can be responsible for their formation. In this work we present an overview of the main mass wasting features (submarine canyons, landslides, debris flows) observed and mapped in different sectors of the northern Sicilian margin. The margin is characterized by a narrow, steep continental shelf (1-2°) and a very irregular and steep (6-8°) upper slope. The main aims of this work are: (1) to outline th…
Cationic microemulsion hosting polynucleotides: Effect of NaCl on host and guest
2004
The structural features of the quaternary water-in-oil microemulsion CTAB/n-hexane/n-pentanol/water in the presence of fairly high concentrations of NaCl and of relatively high molecular weight polynucleotides have been determined. Even in these severe conditions, the hosting system can still be depicted as formed by water droplets stabilised by a surfactant/cosurfactant layer. Moreover, the time stability of the host/guest system has been evaluated and the phase behaviour of the hosting system in the presence of increasing concentrations of NaCl determined.
Late Quaternary marine ostracods of the Basque Basin (S Bay of Biscay): taxonomy and distribution
2018
Late Quaternary taxonomy and ecologic and age distributions of ostracods from the Basque Basin (S Bay of Biscay) are described. More than forty-four thousands ostracod specimens have been obtained from one hundred surface samples and core samples from six cores located in shelf and upper bathyal depths and other infrabathyal core as comparative deep reference. A total of 155 species have been taxonomically described, belonging to 67 genera. Most characteristic species (123) have been SEM figured, and ecologic-geographic distributions and ages have been provided for all species. The resulting database will be a useful help for palaeoceanographic and palaeoclimatologic studies of the region.