For example, assume the shelter is in an area of heavy fallout and the dose rate outside is 400 roentgen (R) per hour, enough to give a potentially fatal dose in about an hour to a person exposed in the open. If a person needs to be exposed for only 10 seconds to dump a bucket, in this 1/360 of an hour he will receive a dose of only about 1 R. Under war conditions, an additional 1-R dose is of little concern." In peacetime, radiation workers are taught to work as quickly as possible when performing a task that exposes them to radiation. For instance, the recovery of a radioactive source should be done as quickly as possible. Shielding
Matter attenuates radiation in most cases, so placing any mass (e.g., lead, dirt, sandbags, vehicles, water, even air) between humans and the source will reduce the radiation dose. This is not always the case, however; care should be taken when constructing shielding for a specific purpose. For example, although high atomic number materials are very effective in shielding photons, using them to shield beta particles may cause higher radiation exposure due to the production of bremsstrahlung x-rays, and hence low atomic number materials are recommended. Also, using material with a high neutron activation cross section to shield neutrons will result in the shielding material itself becoming radioactive and hence more dangerous than if it were not present.There are many types of shielding strategies that can be used to reduce the effects of radiation exposure.
Typically, patients diagnosed with LG (medium age 58 years) have been asymptomatic at presentation with their disease being detected during GI tract examinations done for other reasons. Three of twenty patients diagnosed with LG complained of pain or discomfort in the upper abdominal region. Symptomatic individuals with either disease generally have a long history of persistent or intermittent symptoms. Pathophysiology
NK cells normally occupy the GI tract where they contribute to innate immunity by becoming active in killing pathogen-infected and cancerous cells. The proliferating lymphocytes in NKCE and LG express CD56 and CD7 proteins on their cell surface membrane, CD3γ protein in their cytoplasm, and granzyme B, perforin, and T-cell intracellular antigen-1 cytotoxic proteins within their cytoplasmic granules. This pattern of protein expression identifies these cells as NK cells that, because of their expression of the cytotoxic granule-bound proteins, have been activated. However, the cause(s) for the activation of these cells as wells as for their rapid proliferation to produce NKCE and LG is unknown. To date, no evidence of NK cell clonality (i.e. cells developing from a single precursor) or for these cells to bear gene mutations or chromosome abnormalities have been reported in NKCE or LG. These findings help distinguish LB and NKCE from many lymphomas and support the conclusion that neither disease is malignant. The NK cells in LG and NKCE are not infected with the Epstein-Barr virus (EBV), as evidenced by their failure to express this viruss latency proteins and latency ncRNAs.