The principal objective of radiation protec­tion is to ensure that the dose received by any individual does not exceed the applicable M.P.D. values.We will discuss in this paper the presents recommendations and technical information related to the design and installation of struc­tural shielding with taking into account the concept of Maximum Permissible Dose equi­valent (MPDl as expressed and ...

During space flight, careful and complete physical measurements are made to characterize the radiation dose that is received by the astronauts. Biological changes are also evaluated in the astronauts to determine any biological changes induced by radiation during the space flight. Biological evaluations are done both before and after the space flight to ensure that the effects were induced by t...

Life has evolved on Earth for 3 billion years in the presence of background ionizing radiation (IR). All organisms on Earth are continuously exposed to varying amounts of natural radiation and they have therefore incorporated in their normal biology a daily stimulus of ultra-low–dose radiation. A question arises about the biological effects of environmental background radiation and whether the ...

Purpose. Electromagnetic radiation with wavelength in the range 100 nm to 1 mm is known as optical radiation and includes ultraviolet radiation, the visible spectrum, and infrared radiation. The deleterious short- and long-term biological effects of ultraviolet radiation, including melanoma and other skin cancers, are well recognized. Infrared radiation may also have damaging biological effects...

In the previous review, the physical aspect of heavy particles, with a focus on the carbon beam was introduced. Particle beam therapy has many potential advantages for cancer treatment without increasing severe side effects in normal tissue, these kinds of radiation have different biologic characteristics and have advantages over using conventional photon beam radiation during treatment. The re...

orthodontic treatment of individuals with metal hypersensitivity is a matter of concern for the orthodontist. orthodontic appliances contain metals like nickel, cobalt and chromium etc. metals may cause allergic reactions and are known as allergens. reaction to these metals is due to biodegradation of metals in the oral cavity. this may lead to the formation of corrosion products and their expo...

Ionizing radiation interacts with biological systems to produce reactive oxygen species and reactive nitrogen species which attack various cellular components. Radio-protectors act as prophylactic agents to shield healthy cells and tissues from the harmful effects of radiation. Past research on synthetic radio-protectors has brought little success, primarily due to the various toxicity-related ...

The average human body contains tens of thousands of miles of vessels that permeate every tissue down to the microscopic level. This makes the human vasculature a prime target for an agent like radiation that originates from a source and passes through the body. Exposure to radiation released during nuclear accidents and explosions, or during cancer radiotherapy, is well known to cause vascular...

Climate change modulates the effects of solar UV radiation on biogeochemical cycles in terrestrial and aquatic ecosystems, particularly for carbon cycling, resulting in UV-mediated positive or negative feedbacks on climate. Possible positive feedbacks discussed in this assessment include: (i) enhanced UVinduced mineralisation of above ground litter due to aridification; (ii) enhanced UV-induced...