Search results for "buffer"
showing 10 items of 230 documents
First determination of magma-derived gas emissions from Bromo volcano, eastern Java (Indonesia)
2015
The composition and fluxes of volcanic gases released by persistent open-vent degassing at Bromo Volcano, east Java (Indonesia), were characterised in September 2014 from both in-situ Multi-GAS analysis and remote spectroscopic (dual UV camera) measurements of volcanic plume emissions. Our results demonstrate that Bromo volcanic gas is water-rich (H2O/SO2 ratios of 56-160) and has CO2/SO2 (4.1 +/- 0.7) and CO2/S-tot (3.2 +/- 0.7) ratios within the compositional range of other high-temperature magma-derived gases in Indonesia. H-2/H2O and H2S/SO2 ratios constrain a magmatic gas source with minimal temperature of 700 degrees C and oxygen fugacity of 10(-17)-10(-18) bars. UV camera sensing on …
Anti-inflammatory Function of High-Density Lipoproteins via Autophagy of IκB Kinase
2015
Background & Aims: Plasma levels of high-density lipoprotein (HDL) cholesterol are frequently found decreased in patients with inflammatory bowel disease (IBD). Therefore, and because HDL exerts anti-inflammatory activities, we investigated whether HDL and its major protein component apolipoprotein A-I (apoA-I) modulate mucosal inflammatory responses in vitro and in vivo. Methods: The human intestinal epithelial cell line T84 was used as the in vitro model for measuring the effects of HDL on the expression and secretion of tumor necrosis factor (TNF), interleukin-8 (IL-8), and intracellular adhesion molecule (ICAM). Nuclear factor-κB (NF-κB)-responsive promoter activity was studied by …
Determination of cow’s milk in non-bovine and mixed cheeses by capillary electrophoresis of whey proteins in acidic isoelectric buffers
2000
An improved method for the determination of cow's milk in non-bovine cheese is reported: electrophoresis of whey proteins in acidic, isoelectric buffers. Two background electrolytes (BGEs) have been tested: (i) 50 mM iminodiacetic acid (pH=isoelectric point=2.30 at 25 degrees C), 0.5% hydroxyethylcellulose, 0.1% Tween 20 and 6 M urea (apparent pH 3.1), E=300 V/cm, for the separation of alpha-lactalbumins (alpha-LAs); (ii) a BGE with the same composition, but supplemented with 10% Tween 20, E=450 V/cm, for the fractionation of beta-lactoglobulins (beta-LGs). Surfactants have a discriminating effect on the retention behaviour of the bovine alpha-LA and beta-LG proteins, owing to the different…
Some observations on the prediction of retention in reversed-phase liquid chromatography using the pH as main factor
2004
Abstract When solutes show acid–base behaviour inside the working pH of a reversed-phase liquid chromatographic (RPLC) column, besides the type and percentage of organic modifier, pH can be included to improve the possibilities of separation. Optimisation based on a retention model is an economical and reliable way to achieve the best resolution. However, the difficulties found in knowing the exact pH values and the dependence of acid−base constants of solutes with mobile phase composition makes the accurate modelling of the retention behaviour as a function of these variables rather difficult. In this work, it is shown that in fact, there is no need to have this information. Based on the e…
Space Charge Effects in a Gas Filled Penning Trap
2001
Mass selective buffer gas cooling is a technique used for ions that are stored in a Penning trap. The technique can be applied to all elements and the mass resolving power achieved has proven to be sufficient to resolve isobars. When not only a few but 106 and more ions are stored at the same time, space charge starts to play a dominant role for the spatial distribution. In addition, the observed cyclotron frequency is shifted. This work investigates these effects by numerical calculations.
Impact of buffer gas quenching on the $^1S_0$ $\to$ $^1P_1$ ground-state atomic transition in nobelium
2017
International audience; Using the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) techniquean optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically populated level. A subsequent investigation of the chemical homologue, ytterbium (Yb, Z = 70), enabled a detailed study of the atomic levels involved in this process, leading to the development of a rate equation model. This paves the way for characterizing resonance ionization spectroscopy (RIS) schemes used in the studyof nobelium and beyond, where atomic properties are c…
A Methodological Approach to Determine Sound Response Modalities to Coastal Erosion Processes in Mediterranean Andalusia (Spain)
2020
Human occupation along coastal areas has been greatly increasing in recent decades and, in many places, human activities and infrastructures are threatened by erosion processes that can produce relevant economic and human losses. In order to reduce such impacts and design sound management strategies, which can range from the &ldquo
Effect of buffer nature and concentration on the chromatographic performance of basic compounds in the absence and presence of 1-hexyl-3-methylimidaz…
2019
Abstract In reversed-phase liquid chromatography, the performance for basic compounds is affected by the interaction of the protonated (cationic) species with the anionic free silanols on the alkyl-bonded stationary phases. Using aqueous-organic mobile phases in the absence of additives, the retention may be too high, and the peaks be broad and asymmetric. The performance is improved by addition to the mobile phase of ionic liquids, from which 1-hexyl-3-methylimidazolium chloride ([C6MIm][Cl]) has especially good characteristics. A recent report has also revealed that the use of the phosphate system as buffer, at varying concentration and pH, may have a significant role in the chromatograph…
Impact Assessment of Skidding Extraction: Effects on Physical and Chemical Properties of Forest Soils and on Maple Seedling Growing along the Skid Tr…
2019
Several studies investigated soil disturbances caused on skid trails by forest logging. However, there is still a lack of knowledge about the severity and the distance of disturbances along both sides from the trails. The aims of this study were: i) to investigate the changes in physical and chemical properties of soil along the sides of skidding trails
Apparent activation energies and apparent frequency factor in polarographic waves of paludrine-Zn(II)
1993
Abstract Arrhenius and Vlcek plots of ac 1 and dp polarograms of paludrine-Zn complexes are tested in order to understand the apparent activation energies and pre-exponential factor, and their dependence on the potential. These empirical treatments are useful for obtaining information about the energetic contributions of the elemental processes associated with the Zn(II) and paludrine ligands in the overall mechanism of reduction of the complex 2:1 on the mercury interface.