Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Separation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed2002

Liquid exclusion-adsorption chromatography, a new technique for isocratic separation of nonionic surfactants. IV. Two-dimensional separation of fatty alcohol ethoxylates with focusing of fractions.

Fatty alcohol ethoxylates can be analyzed using a combination of liquid chromatography under critical conditions as the first dimension and liquid exclusion-adsorption chromatography as the second dimension. Transfer of fractions from the first to the second dimension is achieved using the full adsorption-desorption (FAD) technique. The peaks of interest in the first dimension are trapped on a short precolumn before injecting them into the second dimension. Full adsorption is achieved by increasing the water content in the mobile phase before the FAD column. When the fractions are desorbed by switching to the mobile phase of the second dimension, they are focused and reconcentrated. In this way, a full resolution of oligomers is achieved. As both dimensions are run in isocratic mode, density and refractive index detection can be applied, which allows an accurate quantitation.

Adsorption↗
PubMed1994

Primary charge separation in photosystem I: a two-step electrogenic charge separation connected with P700+A0- and P700+A1- formation.

A PS I membrane preparation from a PS II deficient mutant of Synechocystis sp. PCC 6803 (psb DI/DII/C) was investigated by picosecond photovoltage and fluorescence measurements. The photovoltage kinetics show two distinct phases. At low excitation energies the fast phase correlates with the fluorescence decay time constant of 22 +/- 4 ps. This phase is ascribed to the trapping of excitons as described by the reaction (AntiP700)* A0-->AntiP700+A0-. In addition to this phase, the photovoltage displays a second rising phase of smaller amplitude with a time constant of 50 +/- 15 ps. We assign the latter phase to further electron transfer from A0 to the secondary acceptor, A1. Assuming the protein as a homogeneous dielectric, our results suggest that the transmembrane distance A0-A1 spans only a small part (20 +/- 8%) of the distance P700-A1.

Chlorophyll↗
PubMed2005

Distinguishing separable domains of cognition in human and animal studies: what separations are optimal for targeting interventions? A summary of recommendations from breakout group 2 at the measurement and treatment research to improve cognition in schizophrenia new approaches conference.

At the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) New Approaches Conference, a discussion group focused on directions for future research that are critical to enhancing our understanding of the distinctions among key cognitive domains that have relevance for the development of cognition-enhancing interventions. One set of recommendations emphasizes the need for examining and optimizing the psychometric properties of relevant measurement paradigms from cognitive psychology and cognitive neuroscience. This step is critical to translating many notable advances in these basic fields into measures that would be appropriate for clinical trials. A second set of recommendations focuses on key directions for the development and application of animal models of cognitive processes that would greatly aid the discovery and preclinical testing of potential cognition-enhancing agents. As part of this process, the group noted several existing animal paradigms that have particular promise as measures in the key cognitive domains in schizophrenia identified by the MATRICS Neurocognition Committee.

Animals↗