SSLC - 2014 - Physics

Sasthra Deepthi- FM

Sasthra Deepthi- FM

Simple test for cancer and heart disease

Heart disease and cancer are the two leading causes of death in the United States and many other developed countries. Unfortunately, both diseases can be difficult to diagnose. Because these conditions reflect changes deep inside the body, they just aren’t that easy to detect from the outside. But that could change, thanks to a new type of test.
With only two steps, it promises to be fast, cheap and easy. First, a doctor gives a patient an injection. Later, the patient urinates on a special strip of paper. The paper will change color if a disease is present.
“It works exactly the same as a pregnancy test,” Andrew Warren told Science News. A biomedical engineer at the Massachusetts Institute of Technology, in Cambridge, his group helped design the new test along with researchers at the University of Minnesota in Minneapolis. So far, the test has been used only with laboratory mice.
But other researchers praise the test for its simple and smart approach.
A paradigm (PAIR uh dime) is an idea or theory about how something should be done, made or even thought about. Andres Martinez describes the new test as “brilliant work — a totally different paradigm for detecting disease.” A chemist at California Polytechnic State University in San Luis Obispo, Martinez was not involved in creating the new test.
One common type of diagnostic test looks for any telltale molecules that a sick person’s body naturally releases into the blood. Not this new test. It instead relies on synthetic molecules. It also takes advantage of existing knowledge about the behavior of cancer and a disorder called thrombosis. Thrombosis causes blood clots and often gets worse with heart disease.
The researchers knew that both diseases rely on proteases (PRO tee AY sis). These chemicals act like tiny scissors. In the case of cancer, they snip through proteins to clear the way for growing tumors. In thrombosis, proteases help turn on a chain reaction that can end up forming blood clots. The new test relies on the snipping behavior of proteases. It puts them to work on synthetic molecules injected into the body.
In the first part of the test, doctors inject nanoparticles shaped like little fuzzy worms into a patient’s blood. (A nanometer is one-billionth of a meter. These nanoparticles were mostly between 50 and 80 nanometers long.) The main “body” of each particle consists of tiny balls of rust. Then the researchers coated each particle’s body with a “fur” made from proteins.
The idea is to see whether the injected nanoparticles, as they circulated through the bloodstream, encountered the specific types of proteases associated with some particular disease. Those proteases would set to work snipping away at the protein fur. Once cut free, those protein fragments float freely through the body. Eventually, the body would excrete them in urine.
The second part of the test relies on a type of paper that can detect those released “fur” bits in urine. The paper contains special molecules that grab the protein bits. Adding a special solution to the paper highlights their presence by causing a red line to appear.
In laboratory experiments, the new test detected those bits in mouse urine. By doing so, it correctly identified animals with either blood clots or cancer. Warren’s group described its success February 24 in the Proceedings of the National Academy of Sciences.
The test shows good potential as a screening tool in humans, says James Brooks. A biomedical researcher, he works at Stanford University in Palo Alto, Calif. He thinks, however, that the technique might work better for thrombosis than for cancer. There are more than 100 different types of cancer. And many may not produce as much protease as the cancerous tumors that were screened for in the mouse trials.
Still, the study left him impressed. “It's a very clever technique for detection.”

courtesy-  www.sciencenews.org

Powerful artificial muscles made from fishing line and sewing thread

An international team led by The University of Texas at Dallas has discovered that ordinary fishing line and sewing thread can be cheaply converted to powerful artificial muscles.

The new muscles can lift a hundred times more weight and generate a hundred times higher mechanical power than the same length and weight of human muscle. Per weight, they can generate 7.1 horsepower per kilogram, about the same mechanical power as a jet engine.
In a paper published Feb. 21 in the journal Science, researchers explain that the powerful muscles are produced by twisting and coiling high-strength polymer fishing line and sewing thread. Scientists at UT Dallas's Alan G. MacDiarmid NanoTech Institute teamed with scientists from universities in Australia, South Korea, Canada, Turkey and China to accomplish the advances.
The muscles are powered thermally by temperature changes, which can be produced electrically, by the absorption of light or by the chemical reaction of fuels. Twisting the polymer fiber converts it to a torsional muscle that can spin a heavy rotor to more than 10,000 revolutions per minute. Subsequent additional twisting, so that the polymer fiber coils like a heavily twisted rubber band, produces a muscle that dramatically contracts along its length when heated, and returns to its initial length when cooled. If coiling is in a different twist direction than the initial polymer fiber twist, the muscles instead expand when heated.
Compared to natural muscles, which contract by only about 20 percent, these new muscles can contract by about 50 percent of their length. The muscle strokes also are reversible for millions of cycles as the muscles contract and expand under heavy mechanical loads.
"The application opportunities for these polymer muscles are vast," said corresponding author Dr. Ray Baughman, the Robert A. Welch Distinguished Chair in Chemistry at UT Dallas and director of the NanoTech Institute. "Today's most advanced humanoid robots, prosthetic limbs and wearable exoskeletons are limited by motors and hydraulic systems, whose size and weight restrict dexterity, force generation and work capability."
Baughman said the muscles could be used for applications where superhuman strengths are sought, such as robots and exoskeletons. Twisting together a bundle of polyethylene fishing lines, whose total diameter is only about 10 times larger than a human hair, produces a coiled polymer muscle that can lift 16 pounds. Operated in parallel, similar to how natural muscles are configured, a hundred of these polymer muscles could lift about 0.8 tons, Baughman said.
On the opposite extreme, independently operated coiled polymer muscles having a diameter less than a human hair could bring life-like facial expressions to humanoid companion robots for the elderly and dexterous capabilities for minimally invasive robotic microsurgery. Also, they could power miniature "laboratories on a chip," as well as devices for communicating the sense of touch from sensors on a remote robotic hand to a human hand.
The polymer muscles are normally electrically powered by resistive heating using the metal coating on commercially available sewing thread or by using metal wires that are twisted together with the muscle. For other applications, however, the muscles can be self-powered by environmental temperature changes, said Carter Haines, lead author of the study.
"We have woven textiles from the polymer muscles whose pores reversibly open and close with changes in temperature. This offers the future possibility of comfort-adjusting clothing," said Haines, who started his research career in Baughman's lab as a high school student doing summer research through the NanoExplorers program, which Baughman initiated. Haines earned an undergraduate physics degree from UT Dallas and is now a doctoral student in materials science and engineering.
The research team also has demonstrated the feasibility of using environmentally powered muscles to automatically open and close the windows of greenhouses or buildings in response to ambient temperature changes, thereby eliminating the need for electricity or noisy and costly motors.

---

Story Source:
The above story is based on materials provided by University of Texas at Dallas. Note: Materials may be edited for content and length.

Science Film Festival @ Paravur