Author Archives: zimeng li

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How could women aging slower?

It has been ages since human beings started searching a way to live longer. Scientists has found the secret about how a woman to live longer. They said the more babies a woman giving birth to, the slower she will aging.Well. . .that sounds ridiculous. But, that’s what scientists found.

The length of telomeres were believed related to aging because the length are getting shorter when people are getting old. Scientists found that more babies a women giving birth to, the longer telomeres she will have.

cell-div-illustration

Telomeres are at the endpoint of chromosomes. A chromosomes has four telomeres, and when a chromosomes was copied, the telomeres of the new chromosome will make sure the new chromosome continue doing the job that the old chromosome hasn’t finished. Every time a chromosome was copied, the shorter telomeres the new chromosome will have.  When the telomeres are disappear, the cell will not be functional and die.  As it happens to most cells, people will get old.

https://www.youtube.com/watch?v=6LZm7joBjeI

People will want to have longer telomeres. And, scientists have found that giving birth to baby can make the mother’s telomeres longer. They have picked 75 women from two neighboring tribes of Guatemala. Collect the numbers of baby they have given birth to at 2000 and 2013. And collect their saliva to measure the length of their telomeres. They have found the women who have more alive offspring  have longer telomeres. And, giving birth to one more baby, the length of telomeres will increase 0.059 units.

Scientists explained that when women are pregnant, the amount of estrogen will increase a lot. Estrogen  is a strong antioxidant that can protect the cell from the effect of the shorten telomeres.

 

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Frictions

You must know frictions. And, you probably can tell the roughness of surfaces is the reason why there are frictions. But, have you think about what happened micro-cosmically? I am pretty sure you would say no. So, let’s have a look.

http://umdberg.pbworks.com/w/page/46117252/Friction

Imagine you are pushing a heavy box. The bottom of the box may look smooth, but you will see many microscopic hills and valleys if you consider its micro-structure, so does the ground. Due to the gravity, the box is pushing the ground, so the hills of the box are pushed into the valleys of the ground, and vice versa. To move the box, there must be an applied force which is large enough to squeeze those hills and flat the surfaces. The resistance from the hills prevent being squeezed is known as frictions.

Frictions are very important in our life, but they also cause some wastes of energy. People have worked out many ways to minimize frictions.

https://www.youtube.com/watch?v=glXGDpEOU58

Video source( Flexiguru from YouTube)

Minimization of frictions benefits us a lot. The most representative achievement is maglev. Maglev trains are a transport method that uses magnetic levitation to move vehicles without contacting the track. For maglev, there is no friction between its wheels and tracks, so it can have a very high speed. The maximum speed of normal trains is around 300 km/h, but maglev can achieve 600 km/h which is 2/3 speed of civil airplanes. Moreover, maglev trains move more smoothly and more quietly.

The newest commercial maglev train was built in Shanghai. If you go to Shanghai, don’t miss it.