jueves, 10 de marzo de 2011

Why do we like the sweet taste?

Those who are trying to lose weight will know that one of the first things you should do is let the sweet. And probably, the waiver of cakes, pies, ice cream or chocolate is what most costs.

 This is because the body has a special ability to recognize sugars and has a weakness for this flavor, which is usually done with fattening calorie products. The finding by a team of researchers from the Monell Chemical Senses Center in Philadelphia (USA), with your new mechanisms by which the body detects these flavors, could help 'fool' the body and avoid the extra kilos more.

So far, science knew that the T1R2 + T1R3 receptors were those who allowed the taste cells located in the mouth detect sweet compounds all-natural sugars, sweeteners, fructose and sucrose. However, in a study with mice was not all that taste detection could be explained with these receptors, as when one of them was suppressed rodents were able to continue to recognize the sweetness.

Researchers have delved into this issue and found, as published this week in 'Proceedings of the National Academy of Sciences' (PNAS), which together with these sweet receptor proteins, the body uses other sensors found in the intestine and in the pancreas and, in addition to detecting the sugars are responsible for absorbing and regulating blood glucose levels.

 "Detecting the sweetness of sugars and sweeteners is one of the most important functions of taste cells. If we did not recognize this flavor never satiate us and we would always be hungry. working with mice have discovered that in addition to the taste buds there are other guidelines for which the body senses glucose and other sugars, "explains Margolskee, adding that" finding nutritious sources of sugars is of vital importance to humans and animals, so the body has developed several mechanisms to detect ".

The problem, according to this expert, is that "in western countries eat too much food and very hot, so many people are overfed. "

Efficiently to limit this excessive consumption "we need to better understand how our body recognizes and metabolizes the sugars. To meet our need for sugar without exceeding calorie we must learn to 'trick' the body and give 'pig in a poke', ie products identified as the digestive system but not as sweet calories. And so, we must activate all the channels that are used to detect sugars and deceive everyone. A difficult mission in which we have to keep investigating, "said the expert .

As acknowledged by the authors of the investigation, "the process of recognition of sweet and all the factors involved in it is still not well understood. "

viernes, 4 de marzo de 2011

A new material stronger than steel and more flexible than plastic has been created.

Imagine a material stronger than steel but just as versatile plastic, capable of taking a seemingly infinite variety of forms. For decades, scientists have tried to achieve such a substance that can be molded into complex shapes with the same ease and low cost of plastic, but without sacrificing strength and durability of metal.

Now a team led by Jan Schroers, a scientist at Yale University, has shown that some recently developed metallic glasses can be blow molded like plastics, acquiring complex forms that can not be achieved using normal metal without sacrificing either its strength or durability. These new alloys known as Bulk Metallic Glasses (BMG) could revolutionize for good manufacturing processes.

"These metal alloys appear normal but can be blow-molded so cheap and so easily like plastic, " says Schroers. So far, the team has created a series of complex shapes, including bottles perfect metal boxes, clocks, miniature resonators e biomedical implants, which can be cast in less than a minute and are two times stronger than normal steel.

The cost of materials is the same as the high-end steel, but can be processed so as cheap as plastic. The alloys are composed of different metals such as zirconium, nickel, titanium and copper.

The team molded alloys at low temperatures and low pressures, where the metallic glass softens and flows like plastic, but does not crystallize as a regular metal. This allowed scientists to shape BMGs with unprecedented ease.

Schroers and his team is already using its new processing technique for the fabrication of miniature resonators and MEMS-tiny mechanical devices powered by electricity-, gyroscopes and other applications.

miércoles, 2 de marzo de 2011

A microscope to observe live virus

A team of researchers has developed a microscope that can see objects 50 nm under natural light, a record that multiplies by 20 the previous record. The developers say the device would allow scientists to peek inside the cells and study live virus.

The makers of the new invention, dubbed 'Nanoscopy microspheres' are Professor Lin Li and Dr. Zengbo Wang, School of Mechanical, Aerospace and Civil of the University of Manchester. The researchers, with Li in the lead, with the cooperation of scientists from Singapore and publish the results of their work in the journal Nature Communications. "

So far, the tiny object that a scientist had looked under a microscope with some clarity current measured 0.001 mm, but the new microscope can view objects below the diffraction limit of light.

At first, the device works with a virtual image reflected and expanded microspheres. Then the procedure is combined with a conventional optical microscope to see even greater results. Thus, Li and his colleagues watched images of up to 50 nanometers (a nanometer is a billionth of a meter).
Li and his team argue that in the future serve as a microscope to see even smaller objects.

Researchers say that thanks to its Nanoscopy Biomedicine will delve into the mysteries of living and studying viruses inside our cells.

Today, when scientists want to see really small objects often turn to electric or electron microscopes, but these devices also have limitations and fail to look inside the cells, but only to its surface.

Moreover, although scientists can use fluorescence microscopes pass this barrier, this is only possible after staining the samples with chemicals, but these dyes do not penetrate into the virus.