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Because asphyxiant gases are relatively inert and odorless, their presence in high concentration may not be noticed, except in the case of carbon dioxide (hypercapnia). Toxic gases, by contrast, cause death by other mechanisms, such as competing with oxygen on the cellular level (e.g. carbon monoxide ) or directly damaging the respiratory ...
This concept is described as a binary system using two separate components for the therapy of cancer. Each component in itself is relatively harmless to the cells, but when combined for treatment they produce a highly cytocidal effect which is lethal (within a limited range of 5-9 micrometers or approximately one cell diameter). Clinical trials ...
Cancer starts with a single cell whose operation is disrupted. Normal cell operation is controlled by the chemical structure of DNA molecules, also called chromosomes. When radiation deposits enough energy in organic tissue to cause ionization, this tends to break molecular bonds, and thus alter the molecular structure of the irradiated molecules.
Many gases have toxic properties, which are often assessed using the LC 50 (median lethal concentration) measure. In the United States, many of these gases have been assigned an NFPA 704 health rating of 4 (may be fatal) or 3 (may cause serious or permanent injury), and/or exposure limits (TLV, TWA/PEL, STEL, or REL) determined by the ACGIH professional association.
Radiation used for cancer treatment is called ionizing radiation because it forms ions in the cells of the tissues it passes through as it dislodges electrons from atoms. This can kill cells or change genes so the cells cannot grow. Other forms of radiation such as radio waves, microwaves, and light waves are called non-ionizing.
Lung cancer survival has not improved much in the last 50 years, according to Cancer Research UK, with less than one in 10 (9.5 per cent) of people diagnosed with the disease surviving for 10 ...
When the intensely ionizing particles found in space strike human tissue, it can result in cell damage and may eventually lead to cancer. The usual method for radiation protection is material shielding by spacecraft and equipment structures (usually aluminium), possibly augmented by polyethylene in human spaceflight where the main concern is ...
Some stable helium-3 (two protons and one neutron) is produced in fusion reactions from hydrogen, though its estimated abundance in the universe is about 10 −5 relative to helium-4. [92] Binding energy per nucleon of common isotopes. The binding energy per particle of helium-4 is significantly larger than all nearby nuclides.