Babies are not actually born yellow; it develops when they are first born. Every minute we make lots of red blood cells to replace those that have worn out. When old red blood cells are broken down, a yellow-coloured waste product, called bilirubin, is produced. Bilirubin is insoluble in water until it is metabolised by enzymes in the liver which add sugars to the molecule to help it dissolve meaning that it can be excreted in bile, and in urine. However, a developing baby doesn't need this biochemical pathway for metabolising bilirubin until it is born, because the mother removes the bilirubin via the placenta. But when some babies are first born and can no longer rely on their mother to help remove bilirubin for them, particularly if they are premature or have liver problems, there can be a delay in switching on this metabolic pathway and a backlog of bilirubin builds up around the body, making the child yellow. Because , until it is metabolised, bilirubin is insoluble in water but dissolves very well in fats, it accumulates in the skin, where we store most of our body fats, explaining why the babies appear yellow. If it is allowed to continue for a long time, jaundice can cause permanent damage to the brain, but if the baby is put under a blue light, a photochemical reaction occurs, breaking up the bilirubin and making it water soluble. This allows the baby to excrete the excess bilirubin in its urine. The process was discovered accidentally by Judith Ward who used to take babies into sunlight because she thought it was good for them. Having returned them to the hospital, she found that a previously-jaundiced baby had normally-coloured skin on sun-exposed areas, but yellow skin where the nappy had been. As a result the method was quickly adopted for the treatment of neonatal jaundice.

This is a very common symptom of the menopause. Normally, your ovaries respond to a hormone signal from the brain by beginning to produce eggs, which produce oestrogen as they develop. In response to the oestrogen the brain switches off the hormone signal until the next cycle. Women are born with all the eggs they will ever have already in their ovaries and so as women age, they start to run out of eggs, meaning it cannot produce oestrogen. In response to this, the brain sends even higher levels of hormones to try to encourage the ovaries to produce eggs. It is this increase in hormones from the brain that can cause the symptoms of the menopause. Hormone replacement therapy (HRT) works by increasing oestrogen levels in the blood which, in turn, suppresses the release of the hormones produced by brain and preventing the symptoms. But the increased risk of breast cancer associated with HRT use means that it should probably not be used for longer than about 5 years.

The eustacian tube is a connection from the back of your throat to your middle ear. Without this tube, your middle ear would be like a closed box, so that if you took off in a plane, the air inside your ear would expand and cause pain. The eustacian tubes allow you to equalise the pressure in your ears by letting air in and out. Swallowing several times can cause the pressure to equalise, and you know this has happened when you hear a popping sound. Divers equalise pressure in their ears by holding their noses and blowing. The tubes can get blocked by mucus left over after having a bad cold. With mucus blocking the end of the tube, air can't get past and pressure starts to build up. This is also the reason why people can't always hear very well after having a bad cold. Eventually, the mucus should clea and your ears should return to normal.

The chemicals in asbestos do have a distinct raman spectrum, so a handheld gadget would be a possibility. It could be a useful application.

It is very difficult to fake identity cards properly. Using bank notes as an example, an immense number of security measures have been put into them. Many of these measures are very hard and expensive to fake. One security feature on bank notes is the use of phosphors that give off different colours under light. Therefore, despite concerns about ID cards, they shouldn't be easy to forge.