Collision tumor is a rare phenomenon characterized by coexistence of completely distinct and independent tumors at the same body location.Collision tumors have been reported in different sites.However, they are extremely uncommon in the duodenum.We report the case of a 52-year old man with a collision tumor in the third portion Home Decor of the du
Based on the theory of elastic mechanics, rock mechanics and seepage of porous media, the stress-seepage coupling model of pre-extracted gas through ground wells is established.Combined with the specific engineering examples, the influence of ground stress on the pre-extraction gas effect of the ground well is analyzed.The study results indict that
Prions are self-propagating proteins involved in transmissible spongiform encephalopaties in mammals.An aberrant conformation with amyloid-like features of a cell surface protein, termed prion protein (PrP), is thought to be the essential component of the infectious particle, though accessory co-factor molecules such as lipids and nucleotides may b