Marie Curie died aged 66 on July 4, 1934, killed by aplastic anemia, a disease of the bone marrow. It is likely that the radioactivity she had been exposed to during her career caused the disease.Scientists are now much more cautious in their handling of radioactive elements and X rays than they were in the first few decades after their discovery. Marie Curies own books and papers are so radioactive that they are now stored in lead boxes, which may only be opened by people wearing protective suits.
Sleep and wake are verbs (although we usually use "wake up" for when you stop sleeping, and "go to sleep" for the moment when you begin sleeping): My kids go to sleep at 10 PM. I slept during the 6-hour flight. I wake up at 7 AM and I have to be at work by 8. Yesterday I woke up late because my alarm didn't go off.
You can also use wake up for the action of making someone else stop sleeping: Don't talk so loudly! You'll wake up the baby! Your sister is taking a short nap. Can you wake her up in about 20 minutes? Awake and asleep are adjectives. Use them with the verb to be: He's awake. = He isn't sleeping. He's asleep. = He is sleeping.
It's common to use the expressions stay awake / stay up (to continue awake) and fall asleep (to begin sleeping): On New Year's Eve, my children stay awake until midnight. I always fall asleep in history class - it's so boring!