Researchers cross organic and non-organic nano wires like Mikado sticks and thereby make nanoscale prototype computer electronics. Image by Asmus Dohn.

New data from Chinese-Danish collaboration shows that organic nanoscale wires could be an alternative to silicon in computer chips. The discovery has just been published in the respected scientific journal, Advanced Materials.

Nanochemists from the Chinese Academy of Sciences and the Nano-Science Center, Department of Chemistry have developed nanoscale electric contacts out of organic and inorganic nanowires. In the contact they have crossed the wires like Mikado sticks and coupled several contacts together in an electric circuit. In this way they have produced prototype computer electronics on the nanoscale.

Alternative to silicon computers

Today the foundation of our computers, mobile phones and other electronic apparatus is silicon transistors. A transistor is in principal an on- and off- contact and there are millions of tiny transistors on every computer chip. However, we are reaching the limit for how small we can make transistors out of silicon.

We already use various organic materials in, for example, flat screens, such as OLED (Organic Light Emitting Diode). The new results show how small and advanced devices made of organic materials can become. Thomas Bjørnholm, Director of the Nano-Science Center, Department of Chemistry at University of Copenhagen explains:

- “We have succeeded in placing several transistors consisting of nanowires together on a nano device. It is a first step towards realisation of future electronic circuitry based on organic materials – a possible substitute for today’s silicon-based technologies. This offers the possibility of making computers in different ways in the future.”

Danish-Chinese nanoelectronics

The researchers have used organic nanowires combined with the tin oxide nanowires in a so-called hybrid circuit. As in a Mikado game, the nanowires cross in a device consisting of 4-6 active transistor moieties. The devices have a low operational current, high mobility and good stability and that is essential in order for the material to be able to compete with silicon.

Professor Wenping Hu, Chinese Academy of Sciences is excited over the results:

- “This work is the first significant result of our collaboration with the researchers from the Nano-Science Center. It is a good starting point for our new Danish-Chinese research centre for molecular nano-electronics and it underlines the fact that we can complement each other and that together we can achieve exciting and important results.”

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Chemistry researchers uncover why the archean world was not frozen solid

When Planet Earth was just cooling down from its fiery creation, the sun was faint and young. So faint that it should not have been able to keep the oceans of earth from freezing. But fortunately for the creation of life, water was kept liquid on our young planet. For years scientists have debated what could have kept earth warm enough to prevent the oceans from freezing solid. Now a team of researchers from Tokyo Institute of Technology and University of Copenhagen’s Department of Chemistry have coaxed an explanation out of ancient rocks, as reported in this week’s issue of PNAS

A perfect greenhouse gas

- “The young sun was approximately 30 percent weaker than it is now, and the only way to prevent earth from turning into a massive snowball was a healthy helping of greenhouse gas,” Associate Professor Matthew S. Johnson of the Department of Chemistry explains. And he has found the most likely candidate for an archean atmospheric blanket. Carbonyl Sulphide: A product of the sulphur disgorged during millennia of volcanic activity.

- “Carbonyl Sulphide is and was the perfect greenhouse gas. Much better than Carbon Dioxide. We estimate that a blanket of Carbonyl Sulphate would have provided about 30 percent extra energy to the surface of the planet. And that would have compensated for what was lacking from the sun”, says Professor Johnson.

Strange distribution

To discover what could have helped the faint young sun warm early earth, Professor Johnson and his colleagues in Tokyo examined the ratio of sulphur isotopes in ancient rocks. And what they saw was a strange signal; A mix of isotopes that couldn’t very well have come from geological processes.

- “There is really no process in the rocky mantle of earth that would explain this distribution of isotopes. You would need something happening in the atmosphere,” says Johnson. The question was what. Painstaking experimentation helped them find a likely atmospheric process. By irradiating sulphur dioxide with different wavelengths of sunlight, they observed that sunlight passing through Carbonyl Sulphide gave them the wavelengths that produced the weird isotope mix.

- “Shielding by Carbonyl Sulphide is really a pretty obvious candidate once you think about it, but until we looked, everyone had missed it,” says Professor Johnson, and he continues.

- “What we found is really an archaic analogue to the current ozone layer. A layer that protects us from ultraviolet radiation. But unlike ozone, Carbonyl Sulphide would also have kept the planet warm. The only problem is: It didn’t stay warm”.

Life caused ice-age

As life emerged on earth it produced increasing amounts of oxygen. With an increasingly oxidizing atmosphere, the sulphur emitted by volcanoes was no longer converted to Carbonyl Sulphide. Instead it got converted to sulphate aerosols: A powerful climate coolant. Johnson and his co-workers created a Computer model of the ancient atmosphere. And the models in conjunction with laboratory experiments suggest that the fall in levels of Carbonyl Sulphide and rise of sulphate aerosols taken together would have been responsible for creating snowball earth, the planetwide ice-age hypothesised to have taken place near the end of the Archean eon 2500 million years ago. And the implications to Johnson are alarming:

- “Our research indicates that the distribution and composition of atmospheric gasses swung the planet from a state of life supporting warmth to a planet-wide ice-age spanning millions of years. I can think of no better reason to be extremely cautious about the amounts of greenhouse gasses we are currently emitting to the atmosphere”.

Cancer remains a deadly threat despite the best efforts of science. New hopes were raised a few years ago with the discovery that the uncontrolled growth of cancer cells could be thwarted by blocking the action of proteasomes. Biochemists at the Technische Universitaet Muenchen (TUM) have illuminated a reaction pathway that does just that, in collaboration with researchers from Nereus Pharmaceuticals, based in San Diego, California. In the current issue of the Journal of Medicinal Chemistry, they report insights that could potentially lead to the development of custom-tailored anti-cancer drugs.

What makes cancer cells so dangerous is that they proliferate much more rapidly than other cells. An important contribution to this capability is made by a particular group of proteins, the so-called kinases. And it’s against the kinases that many cancer drugs in development today take aim. Another promising approach came to light a few years ago with the discovery that the proliferation of cancer cells could also be arrested through proteasome inhibition. Yet the first drug to employ this strategy caused a number of severe side-effects. Despite that, the drug is expected to generate revenues of more than a billion U.S. dollars this year.

In the search for alternatives, San Diego-based Nereus Pharmaceuticals homed in on a species of marine bacteria known as Salinispora tropica. These bacteria produce a small molecule that kills affected cells by disabling proteasomes, which serve as their waste processing plants. “In the life cycle of a cell, proteins are always being built up that will need to be demolished after they have done their work,” explains TUM Professor Michael Groll, leader of the research team in Munich. “If this breakdown is blocked, the cells choke on their own waste.”

After promising preclinical trials, the bacteria-produced Salinosporamide A (NPI-0052; Sal-A) has advanced into human clinical trials. “Over millions of years, the bacteria developed this substance into a perfect weapon,” says Dr. Barbara Potts, vice president for chemical and oncological development at Nereus Pharmaceuticals. The ideal cancer drug would kill only cancer cells, while doing the least harm possible to healthy cells. The researchers took a closer look at the pathway for this reaction, in the hope that they might better understand the mechanism and the best approach to future generation analogues.

 The research team of Barbara Potts and Michael Groll managed to produce crystals of proteasomes blocked by Salinosporamide A and determined, through X-ray crystallography, the precise arrangement of the atoms. It became clear why the bacterial poison is so effective:  The molecule fits an opening in the proteasome like a key, and locks it up. A subsequent reaction transforms the molecule to a complex that can no longer be detached, in effect breaking off the key in the lock. Vital processes come to a halt.

Halogen-hydrocarbons are favored in industrial chemistry, because the halogen atom can be easily separated from other groups. It’s just this trick that the Salinispora tropica bacterium employs in the case of Salinosporamide A. It uses a chloride as its so-called “leaving group” to trigger an internal reaction forming a ring-like bond. If the ring is closed, the lock is jammed.

The researchers next produced variants of Salinosporamide A and once again succeeded in crystallizing them and using X-ray techniques for structural analysis. By replacing the chlorine atom with fluorine, they were able to observe the progress of the reaction. After the key had been stuck in the lock for one hour of reaction time, the biochemists were still able to pull it out again. A few hours later, the fluorine was split off, and the lock was blocked.

“After the millions of years that have gone into the evolutionary development of this method in bacteria, it’s unlikely that a better way to block the proteasome is even possible,” Groll says. “Now that we know how the best possible reaction proceeds, we can alter it in targeted ways with the aim of developing tailored proteasomal drugs that will have improved safety and efficacy.”

http://portal.mytum.de/pressestelle/pressemitteilungen/news_article.2009-08-18.7471475400

The Internet Society yesterday announced its new Board of Trustees, comprised of leaders from industry, academia, and the global Internet community.

The diverse and distinguished board membership reflects the Internet Society’s mission of providing global leadership in promoting the open development, evolution, and use of the Internet for the benefit of all people throughout the world.

Members of the Board with terms beginning this year are:

* Eric Burger, Chief Technology Officer at Neustar
* Khaled Koubaa, Founder of the Arab World Internet Institute
* Philip Smith of the Internet Architectures Group of Cisco Systems
* Jonathan Zittrain, Professor of Law at Harvard Law School, where he co-founded its Berkman Center for Internet & Society.

Raúl Echeberría, the Executive Director of LACNIC (the Internet Address Registry for Latin America and the Caribbean), continued as a board member and was selected as the new chair of the Board.

“I look forward to working with the worldwide Internet Society community of members and chapters, and my colleagues on the board, to continue the important work of the Internet Society in promoting access to, and supporting the continued growth of, the Internet while preserving its core values,” said Raúl Echeberría, Chair of the Internet Society’s Board of Trustees.

During its first meeting, the Board formally thanked outgoing chair Daniel Karrenberg for his service over the past three years.

Daniel Karrenberg, Chief Scientist at RIPE NCC, said, “It has been both an honour and a pleasure to chair the board. After three years it is time to take a step back. I look forward to serving another two years as a trustee and to supporting Raul in taking over as chair.”

Continuing Members of the Board of Trustees are:

* Hiroshi Esaki, Professor, The University of Tokyo

* Ted Hardie, Director, Internet and Wireless, for Qualcomm’s Research and Development group

* Daniel Karrenberg, Co-founder and Chief Scientist of RIPE NCC

* Désirée Miloshevic, International Affairs and Policy Development Advisor at Afilias Global Registry Services

* Alejandro Pisanty, Professor, the National University of Mexico

* Patrick Vande Walle, Official of the European Commission

* Bert Wijnen, Research Engineer at RIPE NCC

“The Internet Society Board of Trustees is truly international–a tremendous benefit as we work to fulfill our mission of an Internet that is accessible for everyone, everywhere,” said Lynn St. Amour, President and CEO of the Internet Society.

The Board of Trustees reappointed Ted Hardie as Treasurer and Scott Bradner as Secretary.

Trustees serve in the interest of the Internet Society as a whole, and are appointed or elected by the following groups: Chapters, Organization members, and the Internet Architecture Board (IAB). More information, including biographical details of all Board members and details of the Board selection process are available at: http://www.isoc.org/isoc/general/trustees

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