Combined HRAS and NRAS ablation induces a RASopathy phenotype in mice.

Background: HRAS/NRAS double knockout mice exhibit exceedingly high rates of perinatal lethality due to respiratory failure caused by a significant lung maturation delay. The few animals that reach adulthood have a normal lifespan, but present areas of atelectasis mixed with patches of emphysema and normal tissue in the lung.

Methods: Eight double knockout and eight control mice were analyzed using micro-X-ray computerized tomography and a Small Animal Physiological Monitoring system.

Anthraquinones as Inhibitors of SOS RAS-GEF Activity.

Recent breakthroughs have reignited interest in RAS GEFs as direct therapeutic targets. To search for new inhibitors of SOS GEF activity, a repository of known/approved compounds (NIH-NACTS) and a library of new marine compounds (Biomar Microbial Technologies) were screened by means of in vitro RAS-GEF assays using purified, bacterially expressed SOS and RAS constructs. Interestingly, all inhibitors identified in our screenings (two per library) shared related chemical structures belonging to the anthraquinone family of compounds.

Lucky Guess? Applying Rasch Measurement Theory to Grade 5 South African Mathematics Achievement Data.

The use of multiple-choice items in assessments in the interest of increased efficiency brings associated challenges, notably the phenomenon of guessing. The purpose of this study is to use Rasch measurement theory to investigate the extent of guessing in a sample of responses taken from the Trends in International Mathematics and Science Study (TIMSS) 2015. A method of checking the extent of the guessing in test data, a tailored analysis, is applied to the data from a sample of 2188 learners on a subset of items.