Aflatoxin determinations can be approached many ways. Peanuts and corn are more often contaminated with aflatoxins B1 and B2 than with aflatoxins B1, B2, G1, and G2. Some countries are only interested in B1 content and others are interested in the total aflatoxin content. It is essential to safely handle all experimental materials associated with aflatoxin analyses or the aflatoxigenic fungi. Visual screening of suspect peanut lots, based on the presence of conidial heads of the Aspergillus flavus group, and screening corn for the presence of bright greenish yellow fluorescence (BGYF) are not chemical tests and such screening techniques may allow aflatoxin contaminated lots into commerce. Minicolumn screening procedures should always be used in conjunction with a quantitative method. Several thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) methods are suitable for quantitation and are in general use. Immunochemical methods such as the ELISA or affinity column methods are being rapidly developed. The chemical and immunochemical methods can be reliable if care is taken, using suitable controls and personnel that are well-trained. All analytical laboratories should stress safety and include suitable analytical validation procedures.

Aflatoxins↗

PubMedDate not supplied

Predicting onset of drinking in a community sample of adolescents: the role of expectancy and temperament.

We report results of a prospective examination of the influence of outcome expectancy variables and inherited temperaments on the onset of drinking over a 12-month period in a sample of 1,164 high school students. While univariate prospective analysis indicated that drinkers and nondrinkers were different both on measures of outcome expectancy and temperament, multivariate analysis supported, most strongly, a social learning account of the processes influencing the onset and maintenance of drinking behavior in this sample. The multivariate analysis revealed that only expectancies for enhanced social behavior were consistently associated with the onset of drinking from baseline to 12-month follow-up (p < .001). Among all nondrinkers at baseline, those entertaining higher expectancies about the positive effects of alcohol on social interaction were more likely to begin drinking between baseline and follow-up. At present, few, if any, alcohol abuse prevention studies with adolescents have explicitly attempted to alter alcohol expectancies or to establish a link between expectancy and behavior change. Our results suggest that it may be useful to do so.

Adolescent↗

PubMedDate not supplied

The melibiose carrier of Escherichia coli.

Explore the source record for details and available documents.

Bacterial Proteins↗