Diffusion happens naturally and so does not require energy. Substances like oxygen, carbon dioxide and glucose move in and out of cells by diffusion. If I spray a little perfume over here, ...

Draper and Whitehead and their co-workers 1 have described a phenomenon which they have called ‘diffusion ... of oxygen removed from the alveoli during apnea exceeds the amount of carbon dioxide ...

From the Fifth Surgical Service (Harvard) of the Boston City Hospital. This work was supported by an anonymous gift to the Harvard Medical School. Lund — Assistant Visiting Surgeon, Boston City ...