Been ill for the past week so haven't posted.  Sorry folks, especially Nick.

Still, here we go again.

Today's interesting fact has to do with why we yawn.

There have been many theories as to why we yawn, from threatening possible enemies, to increasing the oxygen we get into our blood, to helping us to wake up.  But lately someone looked at the roof of our mouths with specialist equipment and watched what happens to blood flow, temperature and air flow when we yawn.

The examination of the resultant data suggests that while some of the other suggestions may have some validity, perhaps the biggest reason we yawn is to cool our brains.

The soft palette at the top of our mouths are full of blood vessels that can be used to transfer warmth from the brain into our breath as we breathe out and then colder air coming into our lungs during the yawn then reduces the blood temperature further which then further cools the brain.

And this also explains why we get brain freezes when we accidentally place ice cold foods or drinks on that soft pallet.

Today’s interesting fact has to do with vampire bats and how they find their prey.

Vampire bats do not swoop down on their prey.

Instead they land, shuffle along the ground to the animals they will feed on, then they carefully slice through an artery or vein, and carefully lap up a few teaspoons of blood, before shuffling off to where they take off and go back to their roost.

Vampire bats are very proficient in finding the parts of the body where the blood vessels are close to the skin.

Scientists have recently discovered they use the same heat identifying nerve cells we have in our lips and tongues to find these spots.

But where our nerve cells are set to identify heat that would burn us, the vampire bats heat nerve cells in their lips are have been set the temperature of the blood.

So the vampire bat's lips are heat seekers.

Today's interesting fact has to do with Blood Cells.

Most people know that there are four basic types of blood cells, A, B, AB and O, and that they come either RH positive or RH negative. But most people don't know that there are actually many additional groupings that blood can come in.

To date 30 blood group systems have been recognised. These groupings are based on antigens that can be found on the surface of the blood cell. The antigens can be proteins, carbohydrates, glycoproteins, or glycolipids and over 600 have been identified. Many of the antigens are vary rare or found maily in specific ethnic groups.

These blood groups, are most important when it comes to blood transfusions. By blood typing the main groups, medical personnel can usually easily identify who can receive what blood.

Occasionally these additional blood groupings can cause issues, when the blood is rejected even though it passed the blood typing.

Recently, a lab in Canada has worked out of way of masking these antigens, by coating the blood cells with a layer of sugars, glycoproteins, and glycolipids.

In the lab and in test animals, they have successfully given transfusions of different types of bloods that would normally cause rejection issues without any reduction in the way the blood cells work.

It is going into human testing, and will hopefully be available in the next five years.