Search results for "SEPARATION"
showing 10 items of 865 documents
TASCAを用いたCn, Nh, Fl化学実験のためのHg, Tl, PbのSiO2及びAu表面に対するオンライン化学吸着研究
2018
Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO$_{2}$ and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO$_{2}$ or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO$_{2}$ surface at room temperature. On the other hand, the Hg did no…
Flow cytometric immunophenotyping: principles and pitfalls
1992
Within the last decade flow cytometry (FCM) has become an integral part of basic immunological research. Elaboration of this technology has been intensively stimulated by a rapidly growing sophistication in monoclonal antibody technology and vice versa. At present numerous applications are established that allow an increasingly detailed insight into the immune system, however, automation still must be considered the "cinderella of the arts". Thus, transition of this powerful approach from a basic to a routine clinical procedure is much more difficult than expected. Sufficient usage of flow cytometers still requires some knowledge of physics and its technical applications. Moreover, several …
Generation of monoclonal antibodies against human regulatory T cells.
2009
Abstract Natural CD4 + CD25 + Foxp3 + regulatory T cells (Tregs) control the activation of the immune system and therefore have become a major area of research in immunology. The generation of monoclonal antibodies against human Tregs offers the possibility to discover novel Treg-specific or Treg-associated surface markers and to identify targets for a therapeutic modulation of Tregs. Here we present a methodology optimized to efficiently induce and select mAb against human Tregs by repeated immunization of mice with Tregs from a single donor and a differential two-step flow cytometry-based hybridoma screening procedure.
Comparative analysis of radical scavenging and antioxidant activity of phenolic compounds present in everyday use spice plants by means of spectropho…
2010
Comparative analysis of radical scavenging and antioxidant activities of phenolic compounds present in everyday use spice plants was carried out by means of spectrophotometric and chromatographic methods. Six spice plant samples, namely onion (Allium cepa), parsley (Petroselinum crispum) roots and leaves, celery (Apium graveolens) roots and leaves and leaves of dill (Anethum graveolens) were analyzed. Total amount of phenolic compounds and radical scavenging activity (RSA) was the highest in celery leaves and dill extracts and was the lowest in celery roots. Comparing commonly used spectrophotometric analysis of 2,2-diphenyl-1-picrylhydrazyl (DPPH) RSA of extracts with the results obtained …
Separation of halloysite/kaolinite mixtures in water controlled by sucrose addition: The influence of the attractive forces on the sedimentation beha…
2022
In this work, we propose an easy strategy for the separation of halloysite/kaolinite mixtures in sucrose aqueous solution. Preliminarily, we investigated the influence of the sucrose addition on the colloidal stability of kaolinite nanoplates and halloysite nanotubes (HNTs) dispersed in water. Dynamic Light Scattering (DLS) measurements revealed that the HNTs aqueous mobility is dependent on the sucrose concentration, while the ζ-potential is negligibly affected by the addition of the carbohydrate in the aqueous solvent. On the other hand, any variations on the surface charge and dynamic behavior of kaolinite were detected in the presence of sucrose. The obtained ζ-potential and DLS results…
Gas-liquid chromatographic analyses
1983
Abstract The gas chromatography of mixtures of n -alkyl acetates (CH 3 COOR, R = C 1 —C 8 ) and methyl esters of aliphatic n -carboxylic acids (R′COOCH 3 , R′ = C 1 —C 8 ) and certain of their monochlorinated derivatives has been studied on Carbowax 20M and SE-30 glass capillary columns under the same operating conditions. The separation of the isomeric monochlorinated esters was complete on Carbowax 20M, whereas on SE-30 the peaks of 6- and 7-chlorooctyl acetates and methyl (ω − 1)- and (ω − 2)-chlorooctanoates and -nonanoates partly overlapped. The complete separation of the mixtures could not be achieved, however, on Carbowax 20M, in spite of the use of various operating conditions. The …
Molecular simulation studies of water physisorption in zeolites
2006
We report a series of Grand Canonical Monte Carlo simulations of water adsorption in NaY and NaX faujasite, as well as in silicalite-1. Computed adsorption isotherms and heats of adsorption were in good agreement with the available experiments. The existence of cyclic water hexamers in NaX located in the 12-ring windows, recently disclosed by neutron diffraction experiments (Hunger et al., J. Phys. Chem. B, 2006, 110, 342-353) was reproduced in our simulations. Interestingly enough, such cyclic hexamer clusters were also observed in the case of NaY, in which no stabilizing cation is present in the 12-ring window. We also report cation redistribution upon water adsorption for sodium faujasit…
Adsorption of the anionic surfactant sodium dodecyl sulfate on a C18column under micellar and high submicellar conditions in reversed-phase liquid ch…
2015
Micellar liquid chromatography makes use of aqueous solutions or aqueous-organic solutions containing a surfactant, at a concentration above its critical micelle concentration. In the mobile phase, the surfactant monomers aggregate to form micelles, whereas on the surface of the nonpolar alkyl-bonded stationary phases they are significantly adsorbed. If the mobile phase contains a high concentration of organic solvent, micelles break down, and the amount of surfactant adsorbed on the stationary phase is reduced, giving rise to another chromatographic mode named high submicellar liquid chromatography. The presence of a thinner coating of surfactant enhances the selectivity and peak shape, es…
Membranes Directly Prepared from Solutions of Unsubstituted Cellulose
2005
Summary: Starting from 5 wt.-% solutions of a prehydrolysis kraft pulp ( = 135 kg · mol−1) in the mixed solvent (dimethylacetamide + 7 wt.-% LiCl) we have prepared cellulose membranes on different supports according to the phase inversion process using above all acetone (AC) and 2-propanol as precipitants. In this context we have studied the phase behavior of the quasiternary system (DMAc+LiCl)/AC/cellulose. The obtained membranes are mechanically stable and in their mechanical and separation properties on the whole comparable to membranes consisting of regenerated cellulose. With respect to gas separation the ideal selectivity of CO2 in combination with N2 and O2 turns out to be opposite f…
Arsenic(III) Removal at Low Concentrations by Biosorption usingPhanerochaete chrysosporiumPellets
2013
As(III) removal from dilute aqueous solutions by biosorption onto pellets of the white rot fungus Phanerochaete chrysosporium was investigated. The As(III) uptake capacity was evaluated at low initial concentrations (0.2–1 mg/L) which revealed that the P. chrysosporium pellets were only slightly less efficient than the well studied adsorbent granular ferric hydroxide. Moreover, its performance was much more superior compared to anaerobic granular sludge, another cheaply available bacterial biosorbent. In the studied pH (5–9) and biomass concentration (0.25–1.5 g/L wet weight basis) ranges, no large differences in As(III) removal efficiency were observed. The influence of different ions, com…