Thursday, November 29, 2012

Fast track to building molecules - Nature

Nature Reveals: Technion Researchers uncovered a novel approach to molecular architecture. The significant scientific breakthrough represents an effective solution to a major problem in organic synthesis, and could speed up processes in the pharmaceutical industry.

File:Chirality with hands.svg
 A "chiral" molecule is one that is not superimposable with its mirror image. Like left and right hands that have a thumb, fingers in the same order, but are mirror images and not the same, chiral molecules have the same things attached in the same order, but are mirror images and not the same.

Technion researchers have solved a major problem in organic synthesis with the successful preparation of a new molecular framework.The groundbreaking discovery is reported by the popular scientific journal “Nature.”

“Synthetic organic synthesis is a science that deals with the building of complex organic molecules from simpler elements,” explains Prof. Ilan Marek of the Schulich Faculty of Chemistry at Technion. “One of the greatest applications of this new approach is a quick and efficient synthesis of complex natural materials that may be used in pharmaceutical industry. It must be the goal of the 21st century to accomplish more with less. In today’s society, no one can afford to follow the inefficient route of long and tedious synthesis. We should think organic synthesis differently and I am sure that new transformations that were not possible to perform by conventional methods will soon appear” continues Prof. Marek.

Although, there are still molecular frameworks that are challenging to prepare, the real question of the 21st century is no longer “can we synthesize this molecule”, but rather “how can we synthesize it efficiently, using the fewest number of steps, with optimum convergence, with as little as possible functional group transformations, little or no by-products and maximum atom-efficiency and at minimal cost.” Over the years, Prof. Marek’s research team developed several innovative new synthetic methods that not only fulfil these requirements, but also offer solutions to challenging problems in organic synthesis.

One of these critical challenges is the formation of chiral all-carbon quaternary stereogenic centers in acyclic systems. A chiral molecule is a type of molecule that has a non-superposable mirror image. Human hands are perhaps the most universally recognized example of chirality: the left hand is a non-superposable mirror image of the right hand; no matter how the two hands are oriented, it is impossible for all the major features of both hands to coincide. This difference in symmetry becomes obvious if someone attempts to shake the right hand of a person using his left hand, or if a left-handed glove is placed on a right hand. This characteristic is also present in organic molecules and two mirror images of a chiral molecule are called enantiomers.

Many biologically active molecules are chiral, including the naturally occurring amino acids (the building blocks of proteins) and sugars. In biological systems, most of these compounds are of the same chirality and understanding the origin of chirality may shed some light on the origin of life. In many cases, both enantiomers of a specific material can affect the human body in completely different ways, and therefore understanding these chiral molecular characteristics is of great importance for the pharmaceutical and food industries. The most infamous case of medical disaster was caused by a misunderstanding of the different pharmacological characteristics of two enantiomers of the same material, known as Thalidomide which caused severe birth defects. Many infants were born without limbs because the drug Thalidomide, which was administered to their mothers, could in-vivo interconvert the two enantiomers.

In the context of building molecules, the aldol reaction is one of the most versatile carbon-carbon bond formation processes available to synthetic chemists but also a critical biological reaction in the context of metabolism. However, coming back to efficiency, the aldol reaction combines only two components with the creation of only one new carbon-carbon bond per chemical step. As discussed previously, better efficiency is now necessary in organic synthesis in which several new carbon-carbon bonds should be formed. Moreover, the construction of chiral all-quaternary carbon centers could not be achieved in the previously aldol-based methodologies. In the most recent report published in Nature by Professor Marek and his colleagues, a very efficient solution to this problem has been reported through a completely different approach. In a single-pot operation, starting from classical hydrocarbons, the formation of aldol products containing the desired all-carbon quaternary stereocenter have been prepared through the concomitant formation of three new bonds. This groundbreaking discovery represents an innovative solution to a challenging synthetic problem.

Prof. Ilan Marek, Technion.

For the development of original synthetic approaches, Professor Ilan Marek received the prestigious Royal Society Chemistry Organometallic Award (2011) and in 2012 the Janssen Pharmaceutica Prize for Creativity in Organic Synthesis.

Gili Bisker, Nano students, Technion, MIT & Pure Gold

The launch of a new $5 million program with MIT (Massachusetts Institute of Technology) enables six Technion PhDs to take up postdoctoral fellowships at MIT, with full funding for their first year. The 10-year program is funded to a sum of $500,000 per annum.  Among the five Technion PhDs who accepted the fellowship this inaugural year are two women: Gili Bisker (Nanoscience and Nanotechnology) and Lina Perelman (Civil and Environmental Engineering).

Bisker is researching gold nanoparticles under the supervision of Prof. Dvir Yelin at the Biomedical Engineering Lab. of the Faculty of Biomedical Engineering. Gili's goal is to advance new cures for cancer. "My dream is to develop new therapies and techniques especially for cancer treatments," she says, "where we use gold nanoparticles and laser irradiation to eliminate diseased tissues."

Gili Bisker, advanced student in Nanotechnology.

Sunday, November 25, 2012

Chaotic Evolution and the Lives of Stars

Scientists from Technion -Israel Institute of Technology and the University of Colorado, Boulder have taken a closer look at how star systems and their planets grow old together.

The influence of stellar aging on systems composed of three stars in orbit about each other is particularly intriguing. Binary stars systems where one of the stars is orbited by a planet, react similarly to stellar maturation. Stars and planets in these systems can change orbital partners. In some cases, they may even collide or be expelled from the star system all together. This wild and turbulent scenario may have produced of the brightest star system in the sky, Sirius A and B. These findings raise the possibility that collisions between stars are more common (at least 30 times over) than conventional wisdom has shown.

Most stars either live a solitary existence, or pair up with one other star to make a binary system. However 15 percent of all stars orbit at least two other stars, forming a triple star system. Similarly, planets can be “hosted” by a binary system, which then behave much like a triple star system except that one object is vastly smaller than the other two. The evolution of stars in these systems can generate dramatic outcomes. The aging process of stars involves many major changes: a star can expand to a circumference greater than hundreds of times its original size, and then lose most of its mass in intense winds. At the end of this process the stellar core, a white dwarf, is all that is left behind.  While much work has been devoted to understanding the evolution of single and binary star systems, studies on the evolution of triple stars are novel As is evident in the most recent research of Prof. Hagai Perets from the Faculty of Physics at Technion University, and Dr. Kaitlin Kratter from CU-Boulder, triple-star systems and their evolution are deserving of more interest. “Binary stars are systems that are generally stable,” says Perets. “The triple-star systems, on the other hand, are much more fragile," and thus susceptible to disruption.

Prof. Hagai Perets, Technion Faculty of Physics.

When mass is lost from one star during the ageing process, all of the orbits in the system change. These changes can induce dynamical instability, driving the system into a wild dynamic ‘dance,’ whereby the stars exchange partners until one of them gets expelled from the system altogether. Because the mass losing star begins to swell as it ages, it becomes a large target, significantly increasing its chances of crashing into another star in the midst of its wild ‘dance.’

Ordinarily, stars only collide in dense star clusters (systems with millions of stars packed into a volume of only a few cubic light years; for comparison, within the same volume in the neighbourhood of the Solar system there is only one star – the sun). Even in these dense clusters, the probability of a collision is very low.

“We discovered that when it comes to triple star systems, there is a different picture all together. Star collisions outside of dense star clusters can occur at a rate of 30 times higher in comparison to those coincidental collisions that occur within star clusters,” says Perets.

An answer to a Sirius mystery

According to Perets and Kratter, this type of chaotic evolution may be relevant to one of the best known stars, Sirius – the brightest star in the sky.  Sirius is accompanied by a white dwarf in a binary system, but on a very eccentric orbit. This configuration is unusual for a star in a close orbit to a white dwarf; astronomers normally expect such orbits to be nearly circular, due to the exchange of mass between the stars as they age. The most recent findings show that this strange configuration may be explained if the Sirius binary system is the remnant of a triple system that became unstable and lost a star. “This surprising revelation that the triple evolution scenario we studied could solve the decades old mystery related to our brightest night-time star, Sirius, is very exciting; it appears that Sirius had a much wilder history than we could have ever imagined,” adds Perets.

Planetary “star-hoppers”

What would you do if your neighbourhood started to deteriorate? Would you consider moving to a better neighbourhood? It seems as if planets might make the same decision. Kratter and Perets also investigated systems where one of the three elements is not a star but a planet. Much like the case with three stars, mass loss by the planet-host can drive the planet into an unstable, chaotic orbit. The outcome, says Kratter, is surprising. “A planet can actually change which star it orbits, bouncing back and forth between the two." Sometimes, such a star-hopper will settle down into a new, stable orbit around the companion star.  More often, this story has an unhappy ending. It is more likely that the planet will collide with one of the two stars during its voyages between the two. Such a collision would obliterate the planet.

See source paper: Star Hoppers: Krater and Perets, 2012

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Monday, November 19, 2012

Technion in Chinese


Welcome to Israel's most advanced scanning electron microscope.

Inaugurating the innovative microscope. From right to left: Nobel Laureate in Chemistry Prof. Dan Shechtman, Technion Executive Vice President for Research Prof. Oded Shmueli,  and Prof. Wayne D. Kaplan. Photo: Yoav Becher, Technion Spokesman

The Technion has bought the most advanced scanning electron microscope in Israel, at a cost of 1.3 million dollars.  This is a substantial contribution to the learning process at all levels, and that the microscope will serve all researchers in Israel, as well as the high-tech industry, says Dean of the Faculty of Materials Science and Engineering, Prof. Wayne D. Kaplan

The microscope has sophisticated detectors that not only provide extremely high resolution, but also provide direct information about the material composition and local defects. It has a heating system with temperatures of up to 1100 degrees Celsius, which allows researchers to carry out manufacturing processes in-situ in the microscope, and to directly characterize changes to a material during a specific manufacturing process. Thus, for example, one can directly see solidification of a molten alloy inside the microscope, or track the mechanism by which thin films break-up or agglomerate into individual particles during thermal treatments.

"With this innovative microscope, we can follow the process and discover how to prevent agglomeration, or utilize it", emphasizes Prof. Kaplan. "Thus we developed, together with Prof. Gadi Eisenstein of the Department of Electrical Engineering, new flash memories with a stability and working range that are not currently available, and that are based on tiny platinum particles 4-5 nanometers in size. We produced these particles at the desired size and form, by following the agglomeration process of a continuous layer inside the microscope. This provides us with engineering criteria that we have not had to date".

Dr. Alex Berner and Michael Kalina are responsible for the operation of the advanced microscope, which is part of the Technion's advanced Electron Microscopy Center, and for related training.

Sunday, November 18, 2012

Robots to the Rescue

A team of top engineers from Technion and the Ben gurion University are pooling resources to get the robotic rescue services up and running for use in disaster zones around the world.

Technion snake robot reaches danger zones to save lives.

Extracted from the Times of Israel.

Robots can go places where man dare not, into disaster zones, both natural and man-made. Governments, universities, and corporations around the world are putting significant resources in developing robots to deal with the aftermath of floods, mining collapses, oil spills, nuclear accidents, and other industrial and natural disasters.

The Robotics Challenge program is sponsored by DARPA (Defense Advanced Research Projects Agency), an agency of the United States Department of Defense responsible for the development of new technologies for use by the military. The Israeli team, Robil, is one of eleven that will develop software for the GFE Platform being developed by Boston Dynamics, Inc., based on its Atlas humanoid robot platform and modified to meet the needs of the DARPA Robotics Challenge. The team, the only non-American group invited to participate, was awarded $375,000 to develop the software over the next nine months.

The program was initiated in the wake of some of those modern disasters — including the nuclear accident at Japan’s Fukushima power plant, the Deepwater Horizon oil spill, and the Chilean Copiapó mine collapse. In all those instances, robots were able to accomplish what humans could not, entering danger zones to render assistance. While the robots in those instances acted well, they could have done so much more, said DARPA — and with the help of the Israeli group and 10 other teams, the software to improve and enhance robot performance will soon be available, the US organization said.

“Robil’s team is an ad-hoc consortium led by BGU composed of the leaders of the Israeli robotics industry, including IAI and Cogniteam, and academia, including Ben Gurion Univesity, Bar-Ilan University, and the Technion. It includes 20 key personnel and over 40 graduate students and engineers,” says Robil team leader Prof. Hugo Guterman of BGU’s Department of Electrical and Computer Engineering.

Among the things DARPA wants robots to be able to do are driving utility vehicles at disaster sites, removing debris that prevents rescue workers from entering a disaster zone, opening doors, climbing ladders, opening or closing valves, and even breaking through a concrete wall.

“The DARPA Robotics Challenge program,” according to the organization, “will help directly meet these needs by developing robotic technology for disaster response operations. This technology will improve the performance of robots that operate in the rough terrain and austere conditions characteristic of disasters, and use vehicles and tools commonly available in populated areas. This technology will also work in ways easily understood by subject matter experts untrained in the operation of robots, and be governed by intuitive controls that require little training.”

Nature: New Power for Solar Energy

Rust and sunshine could replace fossil fuels

Using sunlight and ultrathin films of iron oxide, or rust, Technion-Israel Institute of Technology researchers have found a new way to split water molecules into hydrogen and oxygen.

The breakthrough, they say, could lead to less expensive, more efficient ways to store solar energy in the form of hydrogen-based fuels.

"Our approach is the first of its kind," says associate professor Avner Rothschild. "We have found a way to trap light in ultrathin films of iron oxide that are 5,000 times thinner than typical office paper. This is the enabling key to achieving high efficiency and low cost. "

Iron oxide is cheap to produce, stable in water, and – unlike other semiconductors such as silicon – can oxidize water without itself being oxidated, corroded, or decomposed. But it comes with its own problems, most notably its poor electrical transport properties.

Researchers have struggled for years with the tradeoff between light absorption and the separation and collection of photogenerated charge carriers before they die out by recombination.

"Our light-trapping scheme overcomes this tradeoff, enabling efficient absorption in ultrathin films wherein the photogenerated charge carriers are collected efficiently," says Rothschild.

"The light is trapped in quarter-wave or even deeper sub-wavelength films on mirror-like back reflector substrates. Interference between forward- and backward-propagating waves enhances the light absorption close to the surface, and the photogenerated charge carriers are collected before they die off."

The team says the breakthrough could lead to the development of inexpensive solar cells that combine ultrathin iron oxide photoelectrodes with conventional photovoltaic cells based on silicon or other materials to produce electricity and hydrogen. According to Rothschild, these cells could store solar energy for on demand use, 24 hours per day - unlike conventional photovoltaic cells, which provide power only when the sun is shining.

And a bonus, says the team, is that the new light trapping method could cut the need for rare elements such as tellurium and indium by 90 percent, with no compromise in performance.