Monday, August 31, 2009

Blood In Stool When Go To Doctor

The image of a molecule

Molécula de pentaceno (IBM Zurich)

Image even shows the hydrogen atoms on the periphery of pentacene.

For the first time scientists were able to capture the image of a molecule with an unprecedented structural detail, you can even see the chemical bonds that hold it together.

Scientists from IBM research center in Zurich used what is known as atomic force microscope or AFM (its acronym in English).

And although in the past, using similar techniques had been able to observe the physical makeup of a carbon nanotube, it is the first time that the structure can be seen in such detail.

Understanding the molecular structure of this scale, experts say, could help in the design of many things at the molecular level, particularly electronics and even drugs.

The team, which published the details of his research in the journal Science, is the same group that last July for the first time succeeded in measuring the charge of a single atom. Fine Focus

Both IBM Zurich researchers used a version of the AFM acts as a tiny pitch (the tool used for tuning musical instruments).

With this, one of the teeth pitch goes incredibly close to the sample and the other a little further.

When the fork vibrates the nearest tooth experiences a tiny change in the frequency of vibration, simply because it is close to the molecule.

Comparing the frequencies of the two prongs gives a measure of the distance from the nearest tooth thus can effectively establish a "map" of the molecular structure.

This measurement requires extreme precision.

To avoid the effects of stray gas molecules and atomic-scale general shaking experienced by objects at room temperature, the process must be kept under high vacuum and extremely cold temperatures.

However, as the tip of the AFM teeth are not well defined and are not necessarily sharp on the scale of single atoms, it causes blurred images they saw.

Researchers thought they could avoid this effect deliberately choosing only a small molecule (pentacene) -Formed by a carbon atom and one oxygen, and forming an AFM tip sharper and better defined as possible.

with peripheral atoms

Microscopio de fuerza atómica (ATM) (IBM Zurich)

The researchers also measured for the first time succeeded in loading a single atom.

Their measurement of pentacene molecule using the tip of carbon monoxide shows the links between carbon atoms in five linked rings, and even relieves links to the hydrogen atoms on the periphery of the molecule.

As

told the BBC Leo Gross, who led the research team now plans to combine its ability to measure individual loads with this new technique to represent molecules with an unprecedented level of detail.

This, says the scientist, may help in particular to the field of molecular electronics, which is a potential future of electronics in which individual molecules act as switches and transistors.

Although the approach can trace the links that connect ethereal atoms, can not distinguish between atoms of different types. The

team is now trying to use the new technique along with other similar method known as scanning tunneling microscopy (STM)-in which a small voltage is applied along the sample-to determine whether the two methods combined can show the nature of each atom in the AFM images.

This, says Leo Gross, help the whole field of chemistry, including synthetic chemicals used in drug design.

The results, he adds the scientist, will also be of great interest to those studying the world of nanotechnology with similar instruments.

Source: BBC World

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