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C Ruzicka

Publications and source records attributed to C Ruzicka.

3 recordsLinked to original sources
PubMed2001

Towards functional group-specific detection in high-performance liquid chromatography using mid-infrared quantum cascade lasers.

A distributed feedback quantum cascade laser was applied for the first time as a powerful light source for mid-infrared (MIR) detection in liquid chromatography. Fructose and glucose in red wine were separated with an isocratic HPLC system, which was connected to a custom-made flow cell. This flow cell was constructed of two diamond windows with adjustable spacing and two hollow wave-guides for guiding the incoming and outgoing light. The HPLC column based on an ion-exchange resin with calcium(II) counter ion was run at 80 degrees C with 0.04% formic acid as the mobile phase. Under these conditions the carbohydrates could not be completely separated from the organic acids also present in wine. However, the emission of the laser at 1067 cm(-1) matches the absorption maximum of fructose and glucose, whereas the organic acids do not absorb appreciably at this wavenumber. Thus group-specific detection could be achieved. Additionally, the optical path length could be increased from 25 to 125 microm, which is very promising in gaining enhanced sensitivity compared to Fourier transform IR detection.

Calibration↗
PubMed1995

Macrophage-colony-stimulating factor regulates expression of the integrins alpha 4 beta 1 and alpha 5 beta 1 by murine bone marrow macrophages.

We observed that when monocyte/macrophage precursors derived from murine bone marrow were treated with macrophage-colony-stimulating factor (M-CSF), there was a dose-dependent increase in both the number of adherent cells and the degree to which the cells were highly spread. Attachment was supported by fibronectin, but not by vitronectin or laminin, suggesting that the integrins alpha 4 beta 1 and/or alpha 5 beta 1 might mediate this event. Binding to fibronectin was blocked partially by antibodies to either integrin, and inhibition was almost complete when the antibodies were used in combination. By a combination of surface labeling with 125I and metabolic labeling with [35S]methionine and [35S]cysteine, we demonstrated that M-CSF treatment led to increased synthesis and surface expression of the two beta 1 integrins. Since attachment to fibronectin and/or stromal cells plays an important role in the maturation of other hematopoietic lineages, we propose that the action of M-CSF in the differentiation of immature monocytes/macrophages includes stimulated expression of the integrins alpha 4 beta 1 and alpha 5 beta 1, leading to interactions with components of the marrow microenvironment necessary for cell maturation.

Animals↗