PubMed · 11103467
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S Carlson. 2000. Calibrating with cold.. https://doi.org/10.1038/scientificamerican1200-102
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
To discriminate 'alcoholics' and 'non-alcoholics', individual Alc-Indices (determined by methanol, acetone, 2-propanol, gamma-GT and CDT-concentrations) were calculated in a collective of 327 alcohol-impaired drivers with regard to the blood alcohol concentration, the time of the event and the age of the drivers. Applying this new defined Alc-Index, 48% of the drivers investigated could be characterised as alcohol dependent. The prevalence of alcoholics among individuals with blood alcohol concentrations (BAC) higher than 1.9per thousand was more than 80%. The diagnostic value of alcohol concentrations for the recognition of 'alcoholics', considering the legal limit in Germany (1.1per thousand) as well as statistically calculated limits, were compared to the Alc-Index.
A reproducible high-resolution protein separation method is the basis for a successful differential proteome analysis. Of the techniques currently available, two-dimensional gel electrophoresis is most widely used, because of its robustness under various experimental conditions. With the introduction of narrow range immobilized pH gradient (IPG) strips (also referred to as ultra-zoom gels) in the first dimension, the depth of analysis, i.e. the number of proteins that can be resolved, has increased substantially. However, for poorly understood reasons isoelectric focusing on ultra-zoom gels in the alkaline region above pH 7 has suffered from problems with resolution and reproducibility. To tackle these difficulties we have optimized the separation of semipreparative amounts of proteins on alkaline IPG strips by focusing on two important phenomena: counteracting water transport during isoelectric focusing and migration of dithiothreitol (DTT) in alkaline pH gradients. The first problem was alleviated by the addition of glycerol and isopropanol to the focusing medium, leading to a significant improvement in the resolution above pH 7. Even better results were obtained by the introduction of excess of the reducing agent DTT at the cathode. With these adaptations together with an optimized composition of the IPG strip, separation efficiency in the pH 6.2-8.2 range is now comparable to the widely used acidic ultra-zoom gels. We further demonstrated the usefulness of these modifications up to pH 9.5, although further improvements are still needed in that range. Thus, by extending the range covered by conventional ultra-zoom gels, the depth of analysis of two-dimensional gel electrophoresis can be significantly increased, underlining the importance of this method in differential proteomics.
Dechlorination of polychlorinated dibenzo-p-dioxins such as 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) and 1,2,6,7-tetrachlorodibenzo-p-dioxin (1,2,6,7-TCDD) was carried out in a solution of NaOH in 2-propanol in the presence of carbon-supported noble metal catalyst (Pd/C or Rh-Pt/C) at temperatures between 23 and 35 degrees C. At initial concentrations of 140-240 micrograms/ml, 2,7-DCDD and 1,2,6,7-TCDD were efficiently converted to a chlorine-free product, dibenzo-p-dioxin (DD), in high yield (60-80%). The conversion of 2,7-DCDD and 1,2,6,7-TCDD and the yield of DD were hardly affected by the atmosphere (N2 or air). We postulate that the displacement of aromatic chlorines by hydrogen selectively occurs on the catalyst, involving hydrogen-transfer from 2-propanol to the substrates.