Search results for "Concentration."
showing 10 items of 1849 documents
Separation of plasma membrane proteins of cultured human fibroblasts by affinity chromatography on bonded microparticulate silicas.
1984
Abstract Adsorbents for high-performance affinity chromatography were prepared by bonding proteins and reactive Procion triazine dyes to 3-isothiocyanatopropyl- and 3-aminopropylsilicas. The materials prepared were used successfully in the separation of hydrophobic plasma membrane proteins of cultured human fibroblasts. The data obtained show that the reaction of 3-isothiocyanatopropyltriethoxysilane (ITCPS) with the surface hydroxyl groups of silica yields a new and convenient route to preparing an “activated carrier” that is capable of coupling with potential affinity ligands containing amino functional groups. The reaction and bonding procedures of 3-isothiocyanatopropyltriethoxysilane a…
The importance of a highly active and DeltapH-regulated diatoxanthin epoxidase for the regulation of the PS II antenna function in diadinoxanthin cyc…
2005
The present study focuses on the regulation of diatoxanthin (Dtx) epoxidation in the diadinoxanthin (Ddx) cycle containing algae Phaeodactylum tricornutum, Thalassiosira pseudonana, Cyclotella meneghiniana and Prymnesium parvum and its significance for the control of the photosystem II (PS II) antenna function. Our data show that Dtx epoxidase can exhibit extremely high activities when algal cells are transferred from high light (HL) to low light (LL). Under HL conditions, Dtx epoxidation is strongly inhibited by the light-driven proton gradient. Uncoupling of the cells during HL illumination restores the high epoxidation rates observed during LL. In Ddx cycle containing algae, non-photoche…
Resonant Photoelectron Diffraction
2013
A layout of a resonant photoelectron diffraction, RESPED, experiment is described from the theoretical basis to the data acquisition and analysis procedures. The theory of the resonance between the directly emitted photoelectron of a selected valence band and the electron emitted by autoionization (Auger) of the same valence band is presented within a formal frame. The critical issue of the angular symmetry and distribution of the resonating electron is discussed in connection with the current computational protocols for photoelectron diffraction, PED, analysis. A few representative applications are presented, where RESPED is shown to overcome some limitations of conventional PED thanks to …
Influence of mechanoactivation on the adhesion and mechanical properties of metal/oxide interfaces
2005
Properties of interfaces in solid state metal/oxide joints (Al/SiO2, Al/MgO, Al/glass, Mg/MgO, In/glass, Mg/SiO2 etc.) are reported. Interfaces were formed at plastic deformation of metal on the oxide surface at room temperature. Structure, composition, and micromechanical properties of the interfaces are studied by AFM, X-ray diffraction, SIMS, electron, optical microscopy, and precision microindentation. A noticeable adhesion is observed in the regions of maximum shear strain in case of metals with low oxide formation energy. Formation of a reaction zone with oxygen concentration gradient is detected in which the metal near the interface hardens. The effect of mechanoactivation is conside…
Synthesis of single crystalline sub-micron rutile TiO2 rods using hydrothermal treatment in acidic media
2014
Size engineered rutile sub-micron rods were obtained from nanostructured titania under acidic conditions. The synthesis was performed by hydrothermal treatment starting from TiO2-P25 and HCl. The synthesis proceeds in less than two hours and can be up-scaled to several grams in a one-pot reaction by increasing the reaction time. The product is single-phase, and the particles are single crystalline as confirmed by electron diffraction and powder X-ray diffraction analysis. The length of the particles can be varied over a wide range from 100 nm to 1.3 μm by changing the acid concentration. Particle growth is proposed to proceed by a dissolution-recrystallization process via soluble [TiCl6]2− …
Experimental study of boulder concentration effect on flow resistance in gravel bed channels
2021
Abstract Previous studies demonstrated that for open channel flows the power velocity profile can be integrated to obtain the flow resistance law. In this paper the relationship between Γ coefficient of the power velocity distribution, the channel slope and Froude number (Eq. (9) ) is firstly presented. Then the measurements carried out in a laboratory flume covered by hemispheric elements for two different hydraulic conditions (partially inundated and inundated) are used to calibrate this relationship. These elements are placed with a square arrangement and have a concentration range 4–64%. For the two investigated hydraulic conditions, this analysis demonstrates that the relationship to e…
Tentative Recommendation on Terminology and Definitions in Respiratory Physiology: Résumé of the Isott Consensus Session 1992
1994
1 The use of small letters for the symbols “p” (partial pressure), “s” (saturation) and “c” (concentration) (e.g. pO2, sO2, cO2) follows recommendations of the IFCC and IUPAC [4]. This supports the use of contemporary word processing systems and mostly eliminates the need to use subscripts (except for chemical valencies: e.g. O2, CO2, H2CO3 etc.). The potential risk of misinterpretations and double meanings is reduced also (e.g. “cO2” [oxygen concentration] v.s. “CO2” [carbon dioxide] and “sO2” [oxygen saturation] v.s. “sO2” [sulfur dioxide]). 2 The symbol shall include the site of measurement or description, e.g. paO2 (arterial O2 partial pressure), svO2 (mixed venous oxygen saturation), o…
Sample Preparation to Determine Pharmaceutical and Personal Care Products in an All-Water Matrix: Solid Phase Extraction
2020
© 2020 by the authors. Pharmaceuticals and personal care products (PPCPs) are abundantly used by people, and some of them are excreted unaltered or as metabolites through urine, with the sewage being the most important source to their release to the environment. These compounds are in almost all types of water (wastewater, surface water, groundwater, etc.) at concentrations ranging from ng/L to µg/L. The isolation and concentration of the PPCPs from water achieves the appropriate sensitivity. This step is mostly based on solid-phase extraction (SPE) but also includes other approaches (dispersive liquid-liquid microextraction (DLLME), buckypaper, SPE using multicartridges, etc.). In this rev…
Copolymerization of VDF and HFP in Supercritical Carbon Dioxide: A Robust Approach for Modeling Precipitation and Dispersion Kinetics
2012
A kinetic model is developed for the heterogeneous free-radical copolymerization of vinylidene fluoride and hexafluoropropylene in supercritical CO 2. The model accounts for polymerization in both the dispersed (polymer-rich) phase and in the continuous (polymer-free) supercritical phase, for radical interphase transport, diffusion limitations, and chain-length-dependent termination in the polymer-rich phase. A parameter evaluation strategy is developed and detailed to estimate most of the kinetic parameters a priori while minimizing their evaluation by direct fitting. The resulting model predictions compare favorably with the experimental results of conversion and MWD at varying monomer fe…
Direct injection of physiological fluids in micellar liquid chromatography
2000
Abstract Micellar liquid chromatography (MLC), which uses mobile phases of surfactants above the critical micellar concentration, provides a solution to the direct injection of physiological samples by solubilizing the protein components, and coating the analytical column with surfactant monomers to avoid clogging. A review showing the advantages and limitations of this technique over other chromatographic techniques used in drug analysis, working protocols, and examples of application is presented. The possibility of direct sample introduction simplifies and greatly expedites the treatments with reduced cost, improving the accuracy of the procedures. Surfactant monomers and micelles appear…