title: Letter: "Expedition nails".
mesh_terms: D001835:Body Weight; D004032:Diet; D004739:England; D005002:Ethiopia; D005101:Expeditions; D006801:Humans; D009262:Nails / Q000378:metabolism; D005082:Physical Exertion; D011488:Protein Deficiency / Q000150:complications*; D014508:Urea / Q000097:blood
chemical_list: D014508:Urea