Курсовая Работа по английскому языку.
Студент: Нестеренко В.А.
Преподаватель: Федотова Л.А.
THE NEW YORK TIMЕS
Smarter Anti-Clotting Tools
Using infinitesimal particles of gold, researchers have discovered a way to stop blood from clotting, and then make it clot again.
The technique could greatly improve surgical procedures, said Kimberly Hamad-Schifferli, a bioengineer at the M.I.T. Lincoln Laboratory who was involved with the research. She and her colleagues reported their findingsin the journal PLoS One.
Today, surgeons rely on blood thinners like heparin to prevent clots from forming during operations. These thinners do a good job with clot prevention, but then take time to wash out of the bloodstream.
“Having that reversible switch is important,” Dr. Hamad-Schifferli said. “During surgery you want to temporarily suspend clotting, and when the surgery is done, you want to restore it.”
She and her team mixed strands of DNA attached to gold nanoparticles less than one-ten-thousandth the width of a hair into test tubes of human blood.
“When you make gold this small,” Dr. Hamad-Schifferli said, “its possible to use infrared light to excite it.” So they used infrared laser beams to cause the particles to release strands of DNA that prevented clotting and then to release other strands that restored clotting.
These lasers could be incorporated into the instruments that surgeons already use, Dr. Hamad-Schifferli said, though she added: “Its very far off. It would have to be done in an animal next.”
A Conductor to Flex and See Through
University of Houston researchers say they have developed an electrical conductor that is both highly flexible and transparent, an elusive combination that could help usher in an age of flexible flat-screen televisions and smartphones.
The conductor consists of gold nanomesh electrodes, essentially a network of tightly interconnected, very small gold wires, according to the study, which was published online by Nature Communications. The material is thin enough to achieve “ultrahigh stretchability” resistance increases only slightly, even at a strain of 160 percent and porous enough to let light through. Because it is made of gold, it is less likely than silver or copper conductors to lose conductivity to oxidization, the researchers said.
In the quest for electronics that can be rolled or folded, scientists have long sought a conductor that is highly flexible and transparent. They have struggled, however, to achieve both in a material that is adequately conductive, said Zhifeng Ren, a physicist at the University of Houston and lead author of the paper. In addition to being flexible, the conductor for a flexible smartphone must be transparent to accommodate the touch screen. The conductor could find applications in medical devices as well, Dr. Ren said.
Both Samsung and LG have produced cellphones that can bend or curve, but Dr. Ren says his teams conductor would allow for far more flexible devices. Though the conductor would need to be built and tested at larger sizes, “its quite close to application,” he said. “Not too much extra needs to be done.”
Carbon Catalyst for Half a Century.
CAMBRIDGE, Mass. Mildred Spiewak Dresselhaus, a professor of physics and engineering at the Massachusetts Institute of Technology, walks with a very large carbon footprint, and in her case its a good thing.
For more than half a century, Dr. Dresselhaus has studied the fundamental properties of carbon carbon as graphite, the dark, flaky mineral with which our pencils are pointed, and carbon as liquid, the element with the highest melting point in nature; carbon that is insulator one moment,superconductor the next.
She invented breakthrough techniques for studying individual layers of carbon atoms. She discovered ways to capture the thermal energy of vibrating particles at well-defined “boundaries,” and then to use that heat to make electricity.
She devised carbon fibers that are stronger than steel at a fraction of steels weight. Her research helped usher in the age of nanotechnology, the wildly popular effort to downsize electronic circuits, medical devices and a host of other products to molecular dimensions.
Dr. Dresselhaus recently won the 2012 Kavli Prize in Nanoscience, a $1 million honor that matches the purse size and Scandinavian provenance of a Nobel, if not quite the status. The new award joins a very long list of laurels, among them the National Medal of Science, the Enrico Fermi Award, the presidencies of the American Physical Society and the American Association for the Advancement of Science, 28 honorary doctorates and a stint in the Department of Energy under President Bill Clinton.
Dr. Dresselhaus has also been a prominent advocate for women in physics and engineering, disciplines that are still short on high-ranking female faces and that were outright hostile to women when she began her career in the late 1950s. Even before entering science, she was well accustomed to hostility and hard times, having grown up impoverished in a rough part of the Bronx.
Today, at 81, the woman nicknamed the Queen of Carbon still works long hours in the lab, publishes prolifically, gives talks around the world and plays violin and viola in chamber groups. Married to a fellow physicist, Gene Dresselhaus, she is the mother of four and grandmother of five, including a granddaughter who is coming to M.I.T. this fall to study nanotechnology.
I spoke with Dr. Dresselhaus in her trapezoid-shaped office, under the vivid presence of a Venezuelan sunburst tapestry that covered much of one wall.
Your parents were immigrants from Poland, and your father often couldnt find work. Youve talked about how as a child you had no toys, sometimes no food and a single set of clothes that your mother washed for you each night. Now, with the Kavli award, youre a bona fide member of the 1 percent club. How does that feel?
You know, Its a funny thing. Being a scientist, you dont get a big salary, but its more than you need. When youre busy enjoying what youre doing, you dont spend a lot of money. I wasnt expecting prizes.
You were born in Brooklyn. So how did you end up in the Bronx?
My older brother was a musical prodigy, and he got a scholarship to the Bronx House Music School. We moved to the Bronx when I was 4 to be close to his music school. Then I got a music scholarship myself, at the age of 6, but that was for a school down in Greenwich Village. I had to take the elevated train and then the subway to get there. I cant tell you how many times I fell down those subway stairs. I was carrying too much, my violin, my schoolbooks. I would trip and lose my balance.
You were traveling downtown on your own at age 6?
The scariest part was coming home and getting off the train in the Bronx, when I had to walk through that dangerous neighborhood. But I survived.
I want to read this little passage about you, when you were Mildred Spiewak. “Any equation she can solve; every problem she can resolve. Mildred equals brains plus fun. In math and science shes second to none.”
Where did you get that from?
Its from my mothers 1948 yearbook for Hunter High School. She was a classmate of yours, although she says she didnt know you at the time.
Hunter High School was a real turning point for me. I found out about its existence through the music school. Nobody I knew had gone to one of these special high schools, and my teachers didnt think it was possible to get in. But Hunter sent me a practice exam, and I studied what I needed to know to pass the exam. It was an excellent school with excellent teachers.
By the end you were already known as a science and math whiz. Yet you didnt think a science career was possible.
At that time there were only three kinds of jobs commonly open to women: teaching, nursing and secretarial work. I went on to Hunter College thinking I would be an elementary schoolteacher.
But then you met Rosalyn Yalow, the future Nobel laureate.
I took her class in elementary nuclear physics. It was a tiny class, maybe 3 students, maybe 10. She was a real leader and a very domineering person. You met her and she said, “Youre going to do this.” She told me I should focus on science. She left the exact science unspecified but said I should do something at the forefront of some area. After that, she was always in my life, writing letters of recommendation for me, keeping up with my progress. She died just a year ago. I was the first speaker at her memorial symposium.
You studied with other scientific giants, like Enrico Fermi.