The world's second nuclear explosion was achieved with uranium-235. This isotope is unstable and fissions when struck by a neutron. It is, however, found in natural uranium at a concentration of only 0.7 percent. To be useful in nuclear weapons, the concentration must be increased.
Introduction. Influenza, or flu, is a caused by a virus infecting the respiratory system, meaning your nose, throat, bronchial tubes, and lungs. Flu symptoms are usually more severe than those of the common cold and are more likely to affect other parts of your body.
The influenza itself does not cause damage in the cells directly, it uses them to produce more of itself, which eventually breaks them. It enters the cell, and forces it to stop every other process, only gives genetic information to the nucleus, which has to be used by the cell to produce more of the virus. When the cells defense has failed, it marks itself as Taken over by putting a certain protein to its surface.