W Christopher Siegler

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By taking into consideration band broadening theory and using those results to select experimental conditions, and also by reducing the injection pulse width, peak capacity production (i.e., peak capacity per separation time) is substantially improved for one dimensional (1D-GC) and comprehensive two dimensional (GC×GC) gas chromatography. A theoretical(More)
Development of a comprehensive, three-dimensional gas chromatograph (GC3) instrument is described. The instrument utilizes two six-port diaphragm valves as the interfaces between three, in-series capillary columns housed in a standard Agilent 6890 gas chromatograph fitted with a high data acquisition rate flame ionization detector. The modulation periods(More)
Comprehensive two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) is a versatile instrumental platform capable of collecting highly informative, yet highly complex, chemical data for a variety of samples. Fisher-ratio (F-ratio) analysis applied to the supervised comparison of sample classes algorithmically(More)
The “Sex Reversed” factor (Sxr) leads to development of XX males. The condition is transmitted by XY-Sxr males. The testes of XY-Sxr carriers are characterized by patches of defective spermatogenesis with meiotic failure and appearance of extraordinary large spermatids. In the present study DNA content of the large spermatids is determined by Feulgen DNA(More)
den hellen Schuppenblfittern jtingerer Rhizome kleine br/iunliche Erhebungen (Fig. 1 d, Pfeil). Es handelt sich dabei um die jfingeren Entwicklungsstadien yon Blatthaustorien, die noch nicht in Kontakt mit Wirtswurzeln getreten sind (vgl. Fig. 1 a, Pfeil). Ihre Bildung wurde vermutlich durch einen yon einer Wirtswurzel ausgehenden chemischen Reiz (vgl. [3])(More)
No anesthesia ventilator attached to a circle system is manufactured for use in neonates. However, a small bellows can be supplied for the following anesthesia ventilators: Spiromat NS 656 (NS), Ventilog 2 (V2) and AV1 (Draeger Co.) We investigated the minimal tidal volume delivered by each of the three ventilators. In addition, we tested the performance of(More)
Comprehensive two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) is a highly capable instrumental platform that produces complex and information-rich multi-dimensional chemical data. The data can be initially overwhelming, especially when many samples (of various sample classes) are analyzed with multiple(More)
In einem Doppelblindversuch an 90 Patienten wurde die Verträglichkeit von PTH und ETH miteinander verglichen. Die Auswertung der Ergebnisse nach verschiedenen Gesichtspunkten ergab in jedem Falle eindeutig oder signifikant eine bessere Verträglichkeit von PTH im Vergleich zu ETH. PTH ist als eines der führenden antituberkulösen Mittel anzusehen. In a double(More)
Recent advances in improving the selectivity and performance for a comprehensive, three-dimensional (3D) gas chromatograph (GC(3)) instrument are described. With GC(3), two six-port diaphragm valves are utilized as the interfaces between three, in-series capillary columns housed in a standard GC instrument fitted with a high data acquisition rate flame(More)
For complex sample analysis, there is a need for multidimensional chromatographic instrumentation to be able to separate more compounds, often in shorter time frames. This has led to the development of comprehensive two-dimensional chromatographic instrumentation, such as comprehensive two-dimensional gas chromatography (GC × GC). Lately, much of the focus(More)