Chest Radiology > Pathology > Atelectasis > General. Atelectasis is collapse or incomplete expansion of the lung or part of the lung. This is one of the most common findings on a chest x-ray. It is most often caused by an endobronchial lesion, such as mucus plug or tumor.
A Labradoodle, a crossbreed between a poodle and a retriever. A crossbreed or crossbred usually refers to an organism with purebred parents of two different breeds, varieties, or populations.
Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, in order to achieve offspring with a genetic identity which is closer to that of the parent.It is used in horticulture, animal breeding and in production of gene knockout organisms.his image demonstrates backcrossing of a heterozygous mouse from one genetic background onto another genetic background. In this example, the gene knockout is performed on 129/Sv cells and then backcrossed into the C57B/6J genetic background.