• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 544
  • 246
  • 76
  • 44
  • 20
  • 16
  • 4
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 1074
  • 473
  • 230
  • 225
  • 142
  • 133
  • 132
  • 109
  • 108
  • 104
  • 103
  • 97
  • 94
  • 88
  • 87
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

The development of capillary isotachophoresis for use with electrospray mass spectrometry

Eastwood, Catherine Rachel 2000 (has links)
No description available.
12

A study of microgel particles in aqueous and non-aqueous media using light scattering techniques

Bradbrook, Stewart Mark 1996 (has links)
No description available.
13

Capillary electrophoresis in pure nonaqueous solvents

Salimi-Moosavi, Mir Mohammad Hossein 1 January 1997 (has links)
The use of nonaqueous solvents in capillary electrophoresis (CE) was investigated. Nonaqueous solvents used included methanol, ethanol, acetonitrile, dimethylformamide, and molten salts. Both indirect, and direct UV detection as well as electrochemical detection were examined. The behavior of electroosmotic flow and Joule heating was examined as well as selectivity patterns for a variety of inorganic and organic ionic species. Analytes examined included inorganic anions, alkali and alkaline earth metal ions, alkanesulfonates, alkyl sulfates, linear alkylbenzensulfonates, derivatized and free amino acids, and fatty acids. Selectivity was dependent not only on the nature of the solvent, but also on the nature and concentration of the electrolyte. With many inorganic ions completely reversed separation order relative to aqueous systems was observed. Although the addition of metal ions caused changes in resolution, complete separation of alkanesulfonates (C2-C16) and alkyl sulfates (C8-C18) was possible by a change from protic (methanol) to aprotic conditions (addition of acetonitrile). The partial separation of positional isomers of linear alkyl benzensulfonate homologues (C10-C15) was achieved in methanol/acetonitrile mixtures. The complete separation of alkali and alkaline earth metal ions, which has not been reported to date, and separation of potassium and ammonium were observed in a methanol/imidazole electrolyte. Significantly different migration order was achieved for dansylated amino acids compared to aqueous systems. Changes in selectivity of free amino acids were possible in basic and acidic electrolytes. Complete separation of a wide range of fatty acids (C1-C20) was possible in less than 20 min. The unique selectivity patterns in nonaqueous solvents was related to changes in solvation and ion-interaction effects. The ability to easily adjust selectivity via choice of electrolyte and to inject aqueous samples directly into the nonaqueous electrolytes suggests that such systems may offer significant advantages for many analytical problems. The results illustrate that when selectivity, efficiency, quantitation, and detection limits are taken into consideration, nonaqueous CE approaches should, in many situations, offer a unique alternative to aqueous based CE analyses. Electroosmotic flow was appreciable, and was cathodal in basic solutions. Reversal of electroosmotic flow was observed in the presence of an excess of a strong acid (HCl or HClO4) in the separation electrolyte. The nature of electrolyte anion (chloride, perchlorate, and acetate) and solvent (methanol/acetonitrile mixtures) had significant effects on the electroosmotic flow in acidic conditions. Evidence was observed for ion adsorption (protons and anions) on to silica surfaces and ion-interaction in the electrolyte. Adsorption and ion-interaction could be used to control both the direction and magnitude of electroosmotic flow. Reproducibility of electroosmotic flow was good under appropriate experimental conditions (%RSD = 1.1).
14

Design, testing and optimization of a microfluidic device for capture and concentration of bacteria

Cherla, Srinivas 2005 (has links)
Effective detection of bacterial pathogens in large sample volumes is a challenging problem. Pre-concentration routines currently in practice before the actual detection process are cumbersome and hard to automate. An effort is made to address the problem of volume discrepancy between day-to-day samples and the concentrated samples needed for analysis. Principles of conceptual design are used in formulating the ‘Need Statement’, ‘Function Structure’ and in identifying the ‘Critical Design Parameters’ and ‘Design Constraints’. Electrokinetic phenomena are used to exploit the surface charges on bacteria. Electrophoresis is used to transport the bacteria to electrode surface and “Electrostatic trapping” is then used to capture these microbes on the electrode surface. The captured microbes can then be concentrated in a concentrator unit. A prototype microfluidic device is fabricated for showing the proof of concept. Optimization is done to minimize hydraulic power consumption and wetted volume. Observations from the initial prototype device along with the optimization results are used in building a new prototype device. Operation of this device is demonstrated by capture of bacteria from flow. Qualitative studies are conducted and preliminary quantification is also done.
15

The electrophoretic mobility of milk fat globules

Tjepkema, Roy 1967 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. Typescript. Vita. Description based on print version record. Includes bibliographical references.
16

Increasing the scale of electrophoretic true moving bed enantiomer separations using voltage gradients and filtration enhancement

Thome, Brian Matthew 2006 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, December 2006. Includes bibliographical references.
17

Design, testing and optimization of a microfluidic device for capture and concentration of bacteria

Cherla, Srinivas 2005 (has links)
Effective detection of bacterial pathogens in large sample volumes is a challenging problem. Pre-concentration routines currently in practice before the actual detection process are cumbersome and hard to automate. An effort is made to address the problem of volume discrepancy between day-to-day samples and the concentrated samples needed for analysis. Principles of conceptual design are used in formulating the ‘Need Statement’, ‘Function Structure’ and in identifying the ‘Critical Design Parameters’ and ‘Design Constraints’. Electrokinetic phenomena are used to exploit the surface charges on bacteria. Electrophoresis is used to transport the bacteria to electrode surface and “Electrostatic trapping” is then used to capture these microbes on the electrode surface. The captured microbes can then be concentrated in a concentrator unit. A prototype microfluidic device is fabricated for showing the proof of concept. Optimization is done to minimize hydraulic power consumption and wetted volume. Observations from the initial prototype device along with the optimization results are used in building a new prototype device. Operation of this device is demonstrated by capture of bacteria from flow. Qualitative studies are conducted and preliminary quantification is also done.
18

Gel electrophoretic analysis of bovine sarcoplasmic proteins

Petropakis, Heracles John 8 December 1967 (has links)
The electrophoretic behavior of sarcoplasmic proteins was investigated by the use of vertical acrylamide gel electrophoresis. The first part of the study was concerned with the separation of sarcoplasmic proteins extracted at different times of post-mortem aging. Electrophoresis of the sarcoplasmic extracts by the discontinuous technique, using ten percent acrylamide gels, resulted in the separation of 18 (possibly 20) electrophoretically different proteins. Differences between electrophoretic patterns of sarcoplasmic proteins as post-mortem aging proceeded were slight. Heterogeneity of sarcoplasmic protein fractions obtained by DEAE-cellulose chromatography was investigated by vertical acrylamide gel electrophoresis in the second part of this study. Electrophoretic analyses of the sarcoplasmic fractions from the above separations indicated that the major peaks of the chromatographic profiles were quite heterogeneous. Fraction Areas I and IV, which appeared as single homogeneous chromatographic peaks, showed five and six distinct bands, respectively, when subjected to gel electrophoresis. Once again changes in the electrophoretic patterns at 0 and 10 days of post-mortem aging were slight with main differences being in the density of the bands. The versatility and high resolving power of acrylamide gel electrophoresis for separating sarcoplasmic proteins was demonstrated. Excellent reproducibility of electrophoretic patterns was noted and in most instances, the patterns were clear and showed well-defined bands. Attempts to fractionate sarcoplasmic proteins by density gradient electrophoresis resulted in separations characterized by poor resolution. Graduation date: 1968
19

A study of the possibility of improving Georgia ocher by electrophoresis

Cater, Thomas Johnson. 1939 (has links)
No description available.
20

Temperature gradient gel electrophoresis development and application

Hosseini, Seyed Homayoun 1994 (has links)
No description available.

Page generated in 0.0688 seconds