Nucleus Ionizing radiation

The numerical combination of protons and neutrons in most nuclides is such that the nucleus is quantum mechanically stable and the atom is said to be stable, i.e., not radioactive however, if there are too few or too many neutrons, the nucleus is unstable and the atom is said to be radioactive. Unstable nuclides undergo radioactive transformation, a process in which a neutron or proton converts into the other and a beta particle is emitted, or else an alpha particle is emitted. Each type of decay is typically accompanied by the emission of gamma rays. These unstable atoms are called radionuclides their emissions are called ionizing radiation and the whole property is called radioactivity. Transformation or decay results in the formation of new nuclides some of which may themselves be radionuclides, while others are stable nuclides. This series of transformations is called the decay chain of the radionuclide. The first radionuclide in the chain is called the parent the subsequent products of the transformation are called progeny, daughters, or decay products. 

The process of radioactive decay (also known as radioactivity) involves the ejection from a nucleus of one or more nuclear particles and ionizing radiation. Nuclear fission is a reaction in which the nucleus splits into smaller nuclei, with the simultaneous release of energy. Most radioisotopes undergo radioactive decay processes and are converted into different smaller atoms. 

It has been reported for many years that condensation nuclei can be produced by ionizing radiation. Recent studies have improved the measurement of the activity size distribution of these ultrafine particles produced by radon and its daughters (Reineking, et al., 1985 Knutson, et al., 1985). It seems that the Po-218 ion is formed by the radon decay, is neutralized within a few tens of milliseconds, and then attached to an ultrafine particle formed by the radiolysis generated by the polonium ion recoil. Although there will be radiolysis along the alpha track, those reactions will be very far away (several centimeters) from the polonium nucleus when it reaches thermal velocity. The recoil path radiolysis therefore seems to be the more likely source of the ultrafine particles near enough to the polonium atom to rapidly incorporate it. 

The central dogma of apoptosis is that all the initiating pro-apoptotic stimuli converge on the mitochondrial compartment. Thus, although apoptosis can be initiated elsewhere, the execution phase of apoptosis induced by ionizing radiation needs mitochondria. How do DNA lesions trigger mitochondria Several metabolic pathways coimect mitochondria to the nucleus. 

The primary effect of any ionizing radiation is based on its ability to excite and ionize molecules, and this leads to the formation of free radicals, which fhen initiate reactions such as polymerization and cross-linking or degradation. Accelerated electron beams have energy sufficient to affect the electrons in the atom shell, but not its nucleus, and can therefore only initiate chemical reactions. Typically, the reactions initiated by electron beam are extremely fast and are completed in fractions of a second. 

It is seen from this table that, at the LD50 level, the nucleus has received about the same dose, irrespective of whether X-rays, 3H-dThd or 125I-concanavalin are used as the source of ionizing radiation, while the membrane has received an immense dose with 125I-concanavalin and very little with 3H-dThd. As expected, the cytoplasm lies in between these two extremes. Yet, irradiation of the cytoplasm (single-ion-beam experiments) is not without an effect. It may cause mutations (Wu et al. 1999) and the formation of products that induce apoptosis in nearby (unirradiated) cells (bystander effect Shao et al. 2004). 

Radiation sterilization includes the use of the ionizing radiation of x-rays and gamma-rays. The former are derived from bombardment of a heavy metal target with electrons. Gamma-rays are obtained from atomic nucleus decay from excited to ground state. 

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