Search results for "mixture"

Self-assembly in surfactant-based mixtures driven by acid–base reactions: bis(2-ethylhexyl) phosphoric acid–n-octylamine systems

2013

Structural and dynamic features of bis(2-ethylhexyl) phosphoric acid (HDEHP)-n-octylamine (NOA) mixtures as a function of the NOA mole fraction (X-NOA) have been investigated by SAXS, WAXS, IR, dielectric spectroscopy and polarized optical microscopy. In the 0 <= X-NOA < 0.5 range, mixtures are transparent liquids, while the abrupt formation of a waxy solid characterized by an hexagonal bidimensional structure occurs at X-NOA = 0.5. Such a composition-induced phase transition results from the synergetic effect of the progressive increase in number density of ordered HDEHP-NOA nanodomains with X-NOA. Mainly driven by an HDEHP to NOA proton transfer, the increase of structural order with X-NO…

Panel Summary:Multistimuli and Different Sensory Modalities

1999

Our everyday environment in which we live is characterised by stimuli capable of eliciting our actions (or reactions). Generally our actions are influenced by a number of stimuli which are multimodal.

Metabolism and Lysine Biosynthesis Control in Brevibacterium Flavum: Impact of Stringent Response in Bacterial Cells

2005

Parameters affecting lysine biosynthesis by Brevibacterium flavum RC 115 cells under stringent response conditions (test guanosine 5′-diphosphate 3′-diphosphate accumulation in cells) caused by threonine limitation were investigated. Experimental results confirmed that an increase in lysine biosynthesis by this bacterium under stringent response conditions might be a result of an increase in the intracellular concentration of NADPH as well as lysine export activity.

Microscopic structure of H2O–CO2 mixtures in supercritical conditions

2006

Hydrogels for potential colon drug release by thiol-ene conjugate addition of a new inulin derivative.

2008

Inulin was chosen as a starting polymer for biocompatible, pH-sensitive and biodegradable hydrogels. Three INUDVSA-TT hydrogels were obtained by crosslinking inulin derivatives with trimethylolpropane tris(3-mercaptopropionate) under varying conditions. The resulting hydrogels were cell compatible, as demonstrated by MTS and trypan blue exclusion assays acting on Caco-2 cells, and were biodegraded by inulinase and esterase, thus suggesting their use as colonic drug delivery systems. 2-Methoxyestradiol, an anti-cancer drug, was soaked in INUDVSA-TT hydrogels and its in vitro release and apoptotic effect on Caco-2 cells were evaluated.

Labile carbon alleviates wood ash effects on soil fauna

2008

The combined effects of wood ash, sucrose and oxalic acid on enchytraeid size and biomass, the abundance of microbial-feeding nematodes and pH were studied in a full three-factorial design in laboratory microcosms containing 30 g of Norway spruce forest humus. Wood ash treatment reduced enchytraeid size and abundance, but these effects were offset by sucrose without any change in pH or moisture. The positive effects of sucrose were partially counteracted by oxalic acid. Both carbon compounds increased the abundance of obligate microbial-feeding nematodes, indicating enhanced microbial production.

Volumetric Behaviour of Lime Treated High Plasticity Clay Subjected to Suction Controlled Drying and Wetting Cycles

2017

The paper presents some experimental results collected on samples recovered from an experimental embankment obtained by compacting a lime-treated clay. Samples were collected soon after the in situ compaction and they were cured in controlled environmental conditions for at least 18 months. Mercury intrusion porosimetry tests (MIP) were carried out on freeze-dried specimens to characterize the microstructure of the material. In order to assess the durability of the improved material, laboratory tests focused on the effects of cyclic variations of the degree of saturation on the water retention properties and the volumetric behaviour of the stabilized clay. Collected results show that the li…

Surface Activity of Humic Substances Within Peat Profile

2012

Humic substances are able to reduce the surface tension of their solutions and thus can act as surface-active substances in natural environment and possibly also for industrial applications. The ability to influence the surface tension of humic substance solutions depends on their origin. The objective of this study is a comparison of the ability of humic substances from peat profile to influence the surface tension of their solutions and identification of the structural characteristics of peat humic acids, determining their surfactant properties. Humic acids isolated from peat demonstrated significant impact of the surface tension of their solutions – they act as weak surfactants. The surf…

Highly recyclable surfactant-based supramolecular eutectogels for iodine removal

2022

In this work, we screened several surfactants for their ability to harden Eutectic Mixtures. We found cetyldiethanolamine-N-oxide as the best candidate, which was able to form eutectogel in four eutectic mixtures. Characterization of the gels obtained in terms of thermal stability, rheology and gelation kinetics, showed a prominent influence of the nature of the hydrogen bonding accepting and donating components for the first two parameter and the other one, respectively. Then, we assessed the eutectogels for their ability to adsorb I2, as a model for its radioactive nuclides, from apolar solvent solutions. The best performing gel allowed fast and thorough removal of I2, over a broad range …

Assessment of soil particle erodibility and sediment trapping using check dams in small semi-arid catchments

2017

Check dams can be used as a source of information for studies on sediment characteristics and soil particle erodibility. In this study, sediment yield and grain size distribution (GSD) were measured in twenty small catchments draining into a rock check dam in NW Iran for different runoffs during 2010–2011. Significant correlations were found between sediment yield and slope steepness, vegetation cover and soil erodibility factor (K) of the catchments. The erodibility of soil particles was determined using the comparison of GSD between sediment and original soil. Clay was the most erodible soil particle which showed 2.05 times more percentage in sediment than the original soil. The erodibili…