Israeli Scientist Wins Nobel Prize for Chemistry

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Israeli Scientist Wins Nobel Prize for Chemistry

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An Israeli scientist won this year’s Nobel Prize in Chemistry for discovering quasicrystals, a material in which atoms were packed together in a well-defined pattern that never repeats.

Recent Nobel prizes have generally split credit for scientific advances among two or three people, but this year’s chemistry prize and accompanying 10 million Swedish kronor ($1.4 million) went to a single scientist: Dan Shechtman, 70, a professor of materials science at Technion-Israel Institute of Technology in Haifa. Dr. Shechtman is also a professor at Iowa State University and a researcher at the United States Department of Energy’s Ames Laboratory.

The citation from the Royal Swedish Academy of Sciences states simply, “for the discovery of quasicrystals.”

Such regular but nonrepeating patterns, defined by precise rules, have been known in mathematics since antiquity, and medieval Islamic artists made decorative, nonrepeating tile mosaics, but the phenomenon was thought impossible in the packing of atoms.

Yet Dr. Shechtman discovered the same type of structure in a mix of aluminum and manganese. During a sabbatical in Maryland at the National Bureau of Standards, now known as the National Institute of Standards and Technology, he took a molten glob of the metals and chilled it rapidly. The expectation was that the atoms would have been a random jumble, like glass. Yet when he examined his metal with an electron microscope, Dr. Shechtman found that the atoms were not random.

His notebook recorded the exact date: April 8, 1982.

Scientists believed that crystals in materials all contained repeating patterns. For example, a square lattice has fourfold symmetry. Rotate it by 90 degrees, and it looks identical. A repeating lattice with fivefold symmetry, however, is impossible. On that morning in 1982, the electrons Dr. Shechtman bounced off his aluminum-manganese alloy formed a pattern that indicated tenfold symmetry. Dr. Shechtman himself could not quite believe it. He wrote in his notebook, “10 Fold???”

While a periodic lattice could not produce that pattern, a quasicrystal could.

It took years for Dr. Shechtman to persuade others.

During the announcement, the Nobel committee noted that one colleague initially said, “Go away, Danny,” because he thought there was a simpler explanation for what Dr. Shechtman had observed. Many scientists — notably Linus Pauling, the Nobel-winning giant of chemistry — argued vehemently that Dr. Shechtman’s data could be explained by “twinning,” where two ordinary periodic crystals are fused together at an angle.

“That must have been intimidating,” said Nancy B. Jackson, president of the American Chemical Society. “When he first discovered these materials, nobody thought they could exist. It was one of these great scientific stories that his fellow scientists thought was impossible, but through time, people came to realize he was right.”

Even the definition of crystal had to be changed. Previously, a crystal had been defined as having “a regularly ordered, repeating three-dimensional pattern,” according to the International Union of Crystallography. The new definition, adopted in 1992, states that a crystal is simply a solid with a “discrete diffraction diagram” — that is, something that produces patterns like the ones Dr. Shechtman saw.

That leaves the door open for yet more different kinds of crystals in the future. Quasicrystals have since been found in many other materials, including a naturally occurring mineral from a Russian river. Materials scientists have been exploring quasicrystals because of their distinct properties — they are hard, brittle, slippery, and, unlike most metals, poor conductors of electricity.

Quasicrystals have so far had modest impact in the everyday world. For example, one kind of highly resilient steel, consisting of hard steel quasicrystals embedded within softer steel, is now used in razor blades and thin needles for eye surgery.

“The applications haven’t panned out,” said Patricia A. Thiel, a colleague of Dr. Shechtman at Iowa State and Ames Laboratory who also studies quasicrystals. “But they revolutionized our understanding of how atoms arrange themselves in solids. It was a scientific revolution.”

Israeli leaders expressed delight and pride at the 10th Nobel Prize won by their country, which has a population of less than 8 million. Two years ago, Ada E. Yonath of the Weizmann Institute of Science in Rehovot shared the award for chemistry as well.

Shimon Peres, Israel’s president, spoke by telephone to Mr. Shechtman at a news conference in Haifa and said, “Professor Shechtman, you today brought an enormous gift to the State of Israel, truly.” Prime Minister Benjamin Netanyahu also called and told him, “Every Israeli is happy today, and every Jew in the world is proud.”

Dr. Shechtman was born and educated in Israel. At the news conference, he said, “The celebration is not only for the Technion and the State of Israel but also for science worldwide. There are today thousands of scientists around the world working in this field that I developed, and I am certain they all see this prize as their accomplishment and they really deserve it. Without these thousands, this science would not be where it is today.”

http://www.nytimes.com/2011/10/06/science/06nobel.html?_r=1&hp
 
New periodic element discovered...
:cool:
Evidence for new periodic table element boosted
27 August 2013 > Scientists have presented new evidence for the existence of an unconfirmed element with atomic number 115.
The element is highly radioactive and exists for less than a second before decaying into lighter atoms. First proposed by Russian scientists in 2004, the super-heavy element has yet to be verified by the governing body of chemistry and physics. The new evidence by a Swedish team is published in the journal Physical Review Letters. "This was a very successful experiment and is one of the most important in the field in recent years", said Dirk Rudolph, professor at the division of atomic physics at Lund University, who led the research.

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The new element has not yet been confirmed by the official body for chemistry and physics

After the discovery of element 115, independent confirmation to measure the exact proton number was required, Prof Rudolph told BBC News. He said the finding "goes beyond the standard measurement" which had been observed previously. A new isotope of a potential new element was produced, which transformed into other particles via a radioactive process named alpha decay. The researchers also gained access to data that they say gives them a deeper insight into the structure and properties of super-heavy atomic nuclei. The team bombarded a thin film of the element americium with calcium ions, which allowed them to measure photons in connection with the new element's alpha decay.

Certain energies of the photons (light particles) agreed with the expected energies for X-ray radiation, which acts as a "fingerprint" of a given element. The experiment was conducted at the GSI research facility in Germany, where scientists have previously discovered six other new elements. The potential new element will now be reviewed by a committee which consists of members of the international unions of pure and applied physics and chemistry. They will decide whether to recommend further experiments before the discovery of the new element is acknowledged.

BBC News - Evidence for new periodic table element boosted

See also:

New Super-Heavy Element 115 Confirmed
August 27, 2013 > Scientists say they've created a handful of atoms of the elusive element 115, which occupies a mysterious corner of the periodic table.
The super-heavy element has yet to be officially named, but it is temporarily called ununpentium, roughly based on the Latin and Greek words for the digits in its atomic number, 115. The atomic number is the number of protons an element contains. The heaviest element commonly found in nature is uranium, which has 92 protons, but scientists can load even more protons into an atomic nucleus and make heavier elements through nuclear fusion reactions. Scientists hope that by creating heavier and heavier elements, they will find a theoretical "island of stability," an undiscovered region in the periodic table where stable super-heavy elements with as yet unimagined practical uses might exist.

In experiments in Dubna, Russia about 10 years ago, researchers reported that they created atoms with 115 protons. Their measurements have now been confirmed in experiments at the GSI Helmholtz Centre for Heavy Ion Research in Germany. To make ununpentium in the new study, a group of researchers shot a super-fast beam of calcium (which has 20 protons) at a thin film of americium, the element with 95 protons. When these atomic nuclei collided, some fused together to create short-lived atoms with 115 protons. "We observed 30 in our three-week-long experiment," study researcher Dirk Rudolph, a professor of atomic physics at Lund University in Sweden, said in an email. Rudolph added that the Russian team had detected 37 atoms of element 115 in their earlier experiments. "The results are by and large compatible," Rudolph said.

Super-heavy elements are generally unstable and most last only a fraction of a second before they start to decay. The scientists had to use special detectors to look for the energy signatures for the X-ray radiation predicted to be given off by element 115 as it quickly degrades. A committee from the International Union of Pure and Applied Chemistry (IUPAC), which governs chemical nomenclature, will review the new findings to decide whether more experiments are necessary before element 115 gets an official name. Some of element 115's neighbors have already been christened. Last year, the man-made elements 114 and 116 were named flerovium (Fl) and livermorium (Lv). The new experiments will be detailed in The Physical Review Letters.

New Super-Heavy Element 115 Confirmed | LiveScience
 
Three share in Nobel prize for chemistry...

Nobel Prize in Chemistry awarded to DNA cell repair pioneers
Oct. 7, 2015 -- The 2015 Nobel Prize in Chemistry was awarded Wednesday to three scientists for their discoveries on how cells repair DNA and protect genetic information from complete chemical chaos.
The Royal Swedish Academy of Sciences awarded the Chemistry prize to Tomas Lindahl, Paul Modrich and Aziz Sancar for their independent work on DNA that provided knowledge on how living cells function, which has led to the development of new cancer treatments. The scientists will share a reward of nearly $1 million. Human DNA is constantly damaged by external attacks such as ultraviolet radiation, free radicals and other carcinogenic substances. DNA molecules are also inherently unstable, as thousands of spontaneous changes occur to a cell's genome daily and defects to DNA can materialize during the millions of times cell division takes place in the body every day.

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The Royal Swedish Academy of Sciences decided to award the 2015 Nobel Prize in Chemistry to (from left) Tomas Lindahl, Paul Modrich and Aziz Sancar for their independent work on DNA that provided knowledge on how living cells function.

Lindahl, Modrich and Sancar will share this year's Nobel Prize in Chemistry for "having mapped, at a molecular level, how cells repair damaged DNA and safeguard the genetic information," The Royal Swedish Academy of Sciences said in a statement. "The reason our genetic material does not disintegrate into complete chemical chaos is that a host of molecular systems continuously monitor and repair DNA," the statement adds. Although scientists in the 1970s believed DNA was an extremely stable molecule, Lindahl's work demonstrated that DNA decays at a rate that would make life impossible on Earth. Lindahl, born in Sweden, discovered base excision repair, a molecular mechanism that constantly prevents the collapse of DNA.

Lindahl is currently an emeritus group leader at England's Francis Crick Institute and the emeritus director of Cancer Research UK. Modrich, born in the United States, discovered mismatch repair, a cell mechanism that allows the cell to correct errors that occur when DNA is replicated during cell division. An inherited variant of colon cancer can be caused by hereditary defects to mismatch repair, which reduces error frequency during DNA replication by about a thousand times. Modrich is a researcher at the Howard Hughes Medical Institute non-profit organization and a professor of biochemistry at the Duke University School of Medicine.

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