From the Lawrence Berkeley National Laboratory which addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, and other critical science issues facing today's society.

Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 12 Nobel prizes.

Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 12 Nobel prizes.

Solved: The Mystery of the Nanoscale Crop Circles
Paul Preuss

In strange patterns of a gold-silicon alloy, Berkeley Lab scientists uncover unsuspected secrets and promising routes to nanoscale semiconductor processing

Almost three years ago a team of scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) was performing an experiment in which layers of gold mere nanometers (billionths of a meter) thick were being heated on a flat silicon surface and then allowed to cool. They watched in surprise as peculiar features expanded and changed on the screen of their electron microscope, finally settling into circles surrounded by irregular blisters.

The circles varied in diameter up to a few millionths of a meter, and in the center of each was a perfect square. The mysterious patterns were reminiscent of nothing so much as so-called "alien" crop circles.

Until recently the cause of these strange formations remained a mystery. Now theoretical insights have explained what's happening, and the results have been published online by Physical Review Letters at http://prl.aps.org/abstract/PRL/v108/i9/e096102.

Eagerly melting alloys

When two solids are combined in just the right proportions, changes in chemical bonding may produce an alloy that melts at a temperature far lower than either can melt by itself. Such an alloy is called eutectic, Greek for "good melting." The eutectic alloy of gold and silicon - 81 percent gold and 19 percent silicon - is especially useful in processing nanoscale semiconductors such as nanowires, as well as device interconnections in integrated circuits; it liquefies at a modest 363˚ Celsius, far lower than the melting point of either pure gold, 1064°C, or pure silicon, 1414°C.

"Gold-silicon eutectic liquid can safely solder chip layers together or form microscopic conducting wires, by flowing into channels in the substrate without burning up the surroundings," says Berkeley Lab's Junqiao Wu. "It's particularly interesting for processing nanoscale materials and devices." Wu cites the example of silicon nanowires, which can be grown from beads of eutectic liquid that form from droplets of gold. The beads catalyze the deposition of silicon from a chemical vapor and ride atop continually lengthening nanowire whiskers.

Understanding just how and why this happens has been a challenge. Although eutectic alloys are well studied as solids, the liquid state presents more obstacles, which are particularly formidable at the nanoscale because of greatly increased surface tension - the same surface forces that make it difficult to form ultra-thin films of water, for example, because they pull the water into droplets. At smaller scales the ratio of surface area to bulk increases markedly, and nanoscale structures have been described as virtually "all surface."

These are the conditions that the team led by Wu, who is a faculty scientist in Berkeley Lab's Materials Sciences Division and a professor in the Department of Materials Science and Engineering at the University of California at Berkeley, set out to examine, by creating the thinnest possible films of gold-silicon eutectic alloys. The researchers did so by starting with a substrate of pure silicon, on whose flat surface an extremely thin barrier layer (two nanometers thick) of silicon dioxide had formed. On this surface they laid layers of pure gold, varying the thickness from one trial to the next between just a few nanometers to a hefty 300 nanometers. The silicon dioxide barrier prevented the pure silicon from mixing with the gold.

The next step was to heat the layered sample to 600 °C for several minutes - not hot enough to melt the gold or silicon but hot enough to cause naturally existing pinholes in the thin silicon dioxide layer to enlarge into small weak spots, through which pure silicon could come in contact with the overlying gold. At the high temperature, silicon atoms quickly diffused out of the substrate and into the gold, forming a layer of eutectic gold-silicon alloy nearly the same thickness as the original gold and spreading in a virtually perfect circle from the central pinhole.

When the circular disk of eutectic alloy got large enough it suddenly broke up, disrupted by the high surface energy of the gold-silicon eutectic liquid. The debris was literally pulled to the edges of the disk, piling up around it to leave a central denuded zone of bare silicon dioxide.

In the center of the denuded zone, a perfect square of gold and silicon remained.

Chemistry and crystallography, not aliens

The researchers' most surprising discovery was that the thinner the original gold layer, the faster the eutectic circles expanded. The reaction rate when the gold layers were only 20 nanometers thick was more than 20 times faster than when the layers were 300 nanometers thick. And while at first glance the dimensions of the gold and silicon squares inside the circular denuded zones seemed variable, there was in fact a strict relation between the size of the square and the size of the circle: the radius of the circle was always the length of the square raised to the power of 3/2.

How did the squares get there in the first place? They originated as weak spots that were the sources of the spreading eutectic gold-silicon circles; when the circular eutectic was ruptured the squares filled with the same eutectic, which remained at the centers of the denuded zones. As they cooled, the gold and silicon within the squares separated, leaving sharply defined edges that were pure silicon; the centers were more roughly outlined squares of pure gold.

By slicing through the silicon/silicon dioxide/gold layercake and looking sideways at the structures with an electron microscope, the researchers found that the surface squares were the bases of inverted pyramids, resembling teeth penetrating the thin silicon dioxide layer and embedded in the silicon wafer. The squares were square, in fact, because of the silicon's orientation: the substrate had been cut along the crystal plane that defined the base. The four triangular sides of the pyramids lay along the low-energy planes of the crystal lattice and were defined by their intersections.

What began as a puzzling phenomenon reminiscent of "The X Files," if on a considerably smaller scale than the cosmic, the mystery of the "nanoscale crop circles" eventually yielded to careful observation and theoretical analysis - despite the obstacles posed by high temperatures, nanoscale sizes, instabilities of the liquid state, and extremely rapid time scales.

"We found that the reaction rate in forming small-sized gold-silicon eutectic liquids - and perhaps in many other eutectics as well - is dominated by the thickness of the reacting layers," says Wu. "This discovery may provide new routes for the engineering and processing of nanoscale materials."

Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 12 Nobel prizes.

Hydrogen from Acidic Water:

Mr. Lynn Yarris: Senior science writer Lawrence Berkeley National Laboratory

Berkeley Lab Researchers Develop a Potential Low Cost Alternative to Platinum for Splitting Water

A technique for creating a new molecule that structurally and chemically replicates the active part of the widely used industrial catalyst molybdenite has been developed by researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab). This technique holds promise for the creation of catalytic materials that can serve as effective low-cost alternatives to platinum for generating hydrogen gas from water that is acidic.

Christopher Chang and Jeffrey Long, chemists who hold joint appointments with Berkeley Lab and the University of California (UC) Berkeley, led a research team that synthesized a molecule to mimic the triangle-shaped molybdenum disulfide units along the edges of molybdenite crystals, which is where almost all of the catalytic activity takes place. Since the bulk of molybdenite crystalline material is relatively inert from a catalytic standpoint, molecular analogs of the catalytically active edge sites could be used to make new materials that are much more efficient and cost-effective catalysts.

"Using molecular chemistry, we've been able to capture the functional essence of molybdenite and synthesize the smallest possible unit of its proposed catalytic active site," says Chang, who is also an investigator with the Howard Hughes Medical Institute (HHMI). "It should now be possible to design new catalysts that have a high density of active sites so we get the same catalytic activity with much less material."

Says Long, "Inorganic solids, such as molybdenite, are an important class of catalysts that often derive their activity from sparse active edge sites, which are structurally distinct from the inactive bulk of the molecular solid. We've demonstrated that it is possible to create catalytically active molecular analogs of these sites that are tailored for a specific purpose. This represents a conceptual path forward to improving future catalytic materials."

Chang and Long are the corresponding authors of a paper in the journal Science describing this research titled "A Molecular MoS2 Edge Site Mimic for Catalytic Hydrogen Generation." Other authors are Hemamala Karunadasa, Elizabeth Montalvo, Yujie Sun and Marcin Majda.

Molybdenite is the crystalline sulfide of molybdenum and the principal mineral from which molybdenum metal is extracted. Although commonly thought of as a lubricant, molybdenite is the standard catalyst used to remove sulfur from petroleum and natural gas for the reduction of sulfur dioxide emissions when those fuels are burned. Recent studies have shown that in its nanoparticle form, molybdenite also holds promise for catalyzing the electrochemical and photochemical generation of hydrogen from water. Hydrogen could play a key role in future renewable energy technologies if a relatively cheap, efficient and carbon-neutral means of producing it can be developed.

Currently, the best available technique for producing hydrogen is to split water molecules into molecules of hydrogen and oxygen using platinum as the catalyst. However, with platinum going for more than $2,000 an ounce, the market is wide open for a low cost alternative catalyst. Molybdenite is far more plentiful and about 1/70th the cost of platinum, but poses other problems.

"Molybdenite has a layered structure with multiple microdomains, most of which are chemically inert," Chang says. "High-resolution scanning tunneling microscopy studies and theoretical calculations have identified the triangular molybdenum disulfide edges as the active sites for catalysis; however, preparing molybdenite with a high density of functional edge sites in a predictable manner is extremely challenging."

Chang, Long and their research team met this challenge using a pentapyridyl ligand known as PY5Me2 to create a molybdenum disulfide molecule that, while not found in nature, is stable and structurally identical to the proposed triangular edge sites of molybdenite. It was shown that these synthesized molecules can form a layer of material that is analogous to constructing a sulfide edge of molybdenite.

"The electronic structure of our molecular analog can be adjusted through ligand modifications," Long says. "This suggests we should be able to tailor the material's activity, stability and required over-potential for proton reduction to improve its performance." In 2010, Chang and Long and Hemamala Karunadasa, who is the lead author on this new Science paper, used the PY5Me2 ligand to create a molybdenum-oxo complex that can effectively and efficiently catalyze the generation of hydrogen from neutral buffered water or even sea water. Molybdenite complexes synthesized from this new molecular analog can just as effectively and efficiently catalyze hydrogen gas from acidic water.

"We're now looking to develop molecular analogs of active sites in other catalytic materials that will work over a range of pH conditions, as well as extend this work to photocatalytic systems" Chang says.

Adds Long, "Our molecular analog for the molybdenite active site might not be a replacement for any existing catalytic materials but it does provide a way to increase the density of active sites in inorganic solid catalytic materials and thereby allow us to do more with less."

This research was supported by the DOE Office of Science, in part through the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub.

Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 12 Nobel prizes.

Berkeley Lab Researchers Discover a Rotational Motion of Cells that Plays a Critical Role in Their Normal Development

Mr. Lynn Yarris Senior science writer Lawrence Berkeley National Laboratory

In a study that holds major implications for breast cancer research as well as basic cell biology, scientists with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have discovered a rotational motion that plays a critical role in the ability of breast cells to form the spherical structures in the mammary gland known as acini. This rotation, which the researchers call "CAMo," for coherent angular motion, is necessary for the cells to form spheres. Without CAMo, the cells do not form spheres, which can lead to random motion, loss of structure and malignancy.

"What is most exciting to me about this stunning discovery is that it may finally give us a handle by which to discover the physical laws of cellular motion as they apply to biology," says Mina Bissell, a leading authority on breast cancer and Distinguished Scientist with Berkeley Lab's Life Sciences Division.

Bissell is a corresponding author of a paper describing this work in the Proceedings of the National Academy of Sciences (PNAS), along with Kandice Tanner, a post-doctoral physicist in Bissell's research group. The PNAS paper is titled "Coherent angular motion in the establishment of multicellular architecture of glandular tissues." Other authors were Hidetoshi Mori, Rana Mroue and Alexandre Bruni-Cardoso, also members of Bissell's research group.

Healthy human epithelial cells in breast and other glandular tissue form either sphere-shaped acini or tube-shaped ducts. The cell and tissue polarity (function-enabling spatial orientations of cellular and tissue structures) that comes with the formation of acini is essential for the health and well-being of the breast. Loss of this polarity as a result of cells not forming spheres is one of the earliest signs of malignancy. However, despite all that is known about cell morphogenesis, the fundamental question as to how epithelial cells are able to assemble into spheres that are similar in size and shape to organs in vivo has until now been a mystery.

"We've discovered a novel type of cell motility where single cells undergo multiple rotations and cohesively maintain that rotational motion as they divide and assemble into acini," says Tanner. "We've also demonstrated that this CAMo is a critical function for the establishment of spherical architecture and not simply a consequence of multicellular aggregates. If CAMo is disrupted, the final geometry is not a sphere."

Working with both immortalized and primary human epithelial cells, cultured in a unique 3D gel that serves as a surrogate for the basement membrane (an assay developed by Bissell and colleagues two decades ago), and using 4D live-imaging (3D plus time) confocal microscopy, Tanner, Bissell and their colleagues found that CAMo arises from a centripetal force generated by the flexing of crescent-shaped muscle-like molecules called actomyosin in the cell's cytoskeleton. This centripetal force sets the cell to rotating about an axis. The rotation is slow, barely once an hour, it may run clockwise or counterclockwise, and its axis might shift, but this rotational motion is cohesive. It continues as the cell divides and the subsequent progeny form into acini, bestowing on cells and acini the polarity and the cavity needed for proper form and function. "Without CAMo, the cells lose their way and do not form structures that allow mammary cells to make and secrete milk," says Tanner. "In order to form a polarized sphere, the cells have to be properly oriented so that certain components are up and certain components are down. The CAMo rotation provides the cells with this orientation."

Bissell is renowned for her pioneering work that elucidated the critical role in breast cancer development played by the extracellular matrix (ECM), a network of fibrous and globular proteins in the microenvironment that surrounds a breast cell. Her experiments have shown that when the nucleus of a breast cell fails to receive the proper biochemical cues and signals from the ECM and other components of the microenvironment, cells and tissue lose structure, which opens the door to malignancy. The discovery of CAMo now provides an important missing mechanism that facilitates the reception and response of a breast cell to the cues and signals from the ECM.

"In addition to wanting to know how a single cell and its progeny assemble into polar tissue, we also wanted to know whether cellular dynamics are corrupted by malignant transformation," Bissell says. "In this study, we found that malignant cells do not display CAMo but instead become randomly motile and do not form spheres."

In recent research, Bissell and her group demonstrated that through manipulation of the ECM, malignant cells cultured in an ECM enriched with laminin - a protein that they had shown induces cell quiescence - can undergo a reversion in which their normal phenotype is restored despite their malignant genome. In this new study, Tanner, Bissell and their colleagues found that when malignant cells cultured in the 3D ECM surrogate gel underwent phenotypic reversion in response to signaling inhibitors, CAMo was restored. When CAMo was restored, the reverted cancer cells formed polarized spheres.

"These results complement our early hypothesis that signaling and support by the ECM when cells are in proper context informs both form and function in cells," Bissell says. "The results also suggest that in response to micro environmental cues from the ECM, cells execute a program of cytoskeletal movements that dictate different kinds of motilities. We hypothesize that these motilities direct the formation of a given type of tissue and preclude other multicellular geometries. We believe this is a crucial evolutionary phenomena for multicellular organisms."

In this new study, Tanner and Bissell and their colleagues were surprised to observe a significant delay between the second and third round of breast cell divisions in the 3D ECM surrogate gel. This mitotic delay is similar to the mitotic delay that's been observed during human blastocyst formation and is critical for normal embryogenesis. Tanner says the delay is probably necessary for the progeny to acquire sufficient adhesion so that the CAMo can be maintained for the adhere cells. This finding may provide a possible explanation for how the mammary gland reorganizes after each pregnancy and involution.

"Once the cells are sufficiently adhered to one another, they can continue CAMo as a cohesive unit," Tanner says. "We postulate that this cohesive CAMo motility is the mechanism by which the original structure of the breast tissue is restored following lactation and breast feeding."

The next step for the research team will be to study the effects of CAMo from the perspective of the ECM.

"We would like to look at the interaction of the ECM with a single cell as it undergoes CAMo and show the in vivo relevance," Tanner says.

This research was supported by the U.S. Department of Defense Breast Cancer Program, the National Cancer Institute and the DOE Office of Science.

Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit www.lbl.gov.

Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 12 Nobel prizes.

Berkeley Lab news release:

Berkeley Lab Researchers Develop Inexpensive Technique for Making High Quality Nanowire Solar Cells

Mr. Lynn Yarris Senior science writer Lawrence Berkeley National Laboratory

Solar or photovoltaic cells represent one of the best possible technologies for providing an absolutely clean and virtually inexhaustible source of energy to power our civilization. However, for this dream to be realized, solar cells need to be made from inexpensive elements using low-cost, less energy-intensive processing chemistry, and they need to efficiently and cost-competitively convert sunlight into electricity. A team of researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) has now demonstrated two out of three of these requirements with a promising start on the third.

Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, led the development of a solution-based technique for fabricating core/shell nanowire solar cells using the semiconductors cadmium sulfide for the core and copper sulfide for the shell. These inexpensive and easy-to-make nanowire solar cells boasted open-circuit voltage and fill factor values superior to conventional planar solar cells. Together, the open-circuit voltage and fill factor determine the maximum energy that a solar cell can produce. In addition, the new nanowires also demonstrated an energy conversion efficiency of 5.4-percent, which is comparable to planar solar cells.

"This is the first time a solution based cation-exchange chemistry technique has been used for the production of high quality single-crystalline cadmium sulfide/copper sulfide core/shell nanowires," Yang says. "Our achievement, together with the increased light absorption we have previously demonstrated in nanowire arrays through light trapping, indicates that core/shell nanowires are truly promising for future solar cell technology."

Yang, who holds a joint appointment with the University of California (UC) Berkeley, is the corresponding author of a paper reporting this research that appears in the journal /Nature Nanotechnology/. The paper is titled "Solution-processed core-shell nanowires for efficient photovoltaic cells." Co-authoring this paper with Yang were Jinyao Tang, Ziyang Huo, Sarah Brittman and Hanwei Gao.

Typical solar cells today are made from ultra-pure single crystal silicon wafers that require about 100 micrometers in thickness of this very expensive material to absorb enough solar light. Furthermore, the high-level of crystal purification required makes the fabrication of even the simplest silicon-based planar solar cell a complex, energy-intensive and costly process.

A highly promising alternative would be semiconductor nanowires - one-dimensional strips of materials whose width measures only one-thousandth that of a human hair but whose length may stretch up to the millimeter scale. Solar cells made from nanowires offer a number of advantages over conventional planar solar cells, including better charge separation and collection capabilities, plus they can be made from Earth abundant materials rather than highly processed silicon. To date, however, the lower efficiencies of nanowire-based solar cells have outweighed their benefits.

"Nanowire solar cells in the past have demonstrated fill factors and open-circuit voltages far inferior to those of their planar counterparts," Yang says. "Possible reasons for this poor performance include surface recombination and poor control over the quality of the p-n junctions when high-temperature doping processes are used."

At the heart of all solar cells are two separate layers of material, one with an abundance of electrons that function as a negative pole, and one with an abundance of electron holes (positively-charged energy spaces) that function as a positive pole. When photons from the sun are absorbed, their energy is used to create electron-hole pairs, which are then separated at the p-n junction - the interface between the two layers - and collected as electricity.

About a year ago, working with silicon, Yang and members of his research group developed a relatively inexpensive way to replace the planar p-n junctions of conventional solar cells with a radial p-n junction, in which a layer of n-type silicon formed a shell around a p-type silicon nanowire core. This geometry effectively turned each individual nanowire into a photovoltaic cell and greatly improved the light-trapping capabilities of silicon-based photovoltaic thin films.

Now they have applied this strategy to the fabrication of core/shell nanowires using cadmium sulfide and copper sulfide, but this time using solution chemistry. These core/shell nanowires were prepared using a solution-based cation (negative ion) exchange reaction that was originally developed by chemist Paul Alivisatos and his research group to make quantum dots and nanorods. Alivisatos is now the director of Berkeley Lab, and UC Berkeley's Larry and Diane Bock Professor of Nanotechnology.

"The initial cadmium sulfide nanowires were synthesized by physical vapor transport using a vapor-liquid-solid (VLS) mechanism rather than wet chemistry, which gave us better quality material and greater physical length, but certainly they can also be made using solution process" Yang says. "The as-grown single-crystalline cadmium sulfide nanowires have diameters of between 100 and 400 nanometers and lengths up to 50 millimeters."

The cadmium sulfide nanowires were then dipped into a solution of copper chloride at a temperature of 50 degrees Celsius and kept there for 5 to 10 seconds. The cation exchange reaction converted the surface layer of the cadmium sulfide into a copper sulfide shell.

"The solution-based cation exchange reaction provides us with an easy, low-cost method to prepare high-quality hetero-epitaxial nanomaterials," Yang says. "Furthermore, it circumvents the difficulties of high-temperature doping and deposition for typical vapor phase production methods, which suggests much lower fabrication costs and better reproducibility. All we really need are beakers and flasks for this solution-based process. There's none of the high fabrication costs associated with gas-phase epitaxial chemical vapor deposition and molecular beam epitaxy, the techniques most used today to fabricate semiconductor nanowires."

Yang and his colleagues believe they can improve the energy conversion efficiency of their solar cell nanowires by increasing the amount of copper sulfide shell material. For their technology to be commercially viable, they need to reach an energy conversion efficiency of at least ten-percent.

-- An html version of this press release with images and links to additional information can be viewed at http://newscenter.lbl.gov/news-releases/2011/08/31/down-to-the-wire-berkeley-lab-researchers-develop-inexpensive-technique-for-making-high-quality-nanowire-solar-cells/

Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 12 Nobel prizes.

Better Lithium-Ion Batteries Are On The Way From Berkeley Lab

Paul Preuss 510-486-6249  paul_preuss@lbl.gov

Lithium-ion batteries are everywhere, in smart phones, laptops, an array of other consumer electronics, and the newest electric cars. Good as they are, they could be much better, especially when it comes to lowering the cost and extending the range of electric cars.

To do that, batteries need to store a lot more energy.

The anode is a critical component for storing energy in lithium-ion batteries. A team of scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has designed a new kind of anode that can absorb eight times the lithium of current designs, and has maintained its greatly increased energy capacity after over a year of testing and many hundreds of charge-discharge cycles.

The secret is a tailored polymer that conducts electricity and binds closely to lithium-storing silicon particles, even as they expand to more than three times their volume during charging and then shrink again during discharge.

The new anodes are made from low-cost materials, compatible with standard lithium-battery manufacturing technologies.

High-capacity expansion

Says Liu, "Most of today's lithium-ion batteries have anodes made of graphite, which is electrically conducting and expands only modestly when housing the ions between its graphene layers. Silicon can store 10 times more - it has by far the highest capacity among lithium-ion storage materials - but it swells to more than three times its volume when fully charged."

This kind of swelling quickly breaks the electrical contacts in the anode, so researchers have concentrated on finding other ways to use silicon while maintaining anode conductivity. Many approaches have been proposed; some are prohibitively costly.

One less-expensive approach has been to mix silicon particles in a flexible polymer binder, with carbon black added to the mix to conduct electricity. Unfortunately, the repeated swelling and shrinking of the silicon particles as they acquire and release lithium ions eventually push away the added carbon particles. What's needed is a flexible binder that can conduct electricity by itself, without the added carbon.

"Conducting polymers aren't a new idea," says Liu, "but previous efforts haven't worked well, because they haven't taken into account the severe reducing environment on the anode side of a lithium-ion battery, which renders most conducting polymers insulators."

One such experimental polymer, called PAN (polyaniline), has positive charges; it starts out as a conductor but quickly loses conductivity. An ideal conducting polymer should readily acquire electrons, rendering it conducting in the anode's reducing environment.

The signature of a promising polymer would be one with a low value of the state called the "lowest unoccupied molecular orbital," where electrons can easily reside and move freely. Ideally, electrons would be acquired from the lithium atoms during the initial charging process. Liu and his postdoctoral fellow Shidi Xun in EETD designed a series of such polyfluorene-based conducting polymers - PFs for short.

When Liu discussed the excellent performance of the PFs with Wanli Yang of Berkeley Lab's Advanced Light Source (ALS), a scientific collaboration emerged to understand the new materials. Yang suggested conducting soft x-ray absorption spectroscopy on Liu and Xun's candidate polymers using ALS beamline 8.0.1 to determine their key electronic properties.

Says Yang, "Gao wanted to know where the ions and electrons are and where they move. Soft x-ray spectroscopy has the power to deliver exactly this kind of crucial information."

Compared with the electronic structure of PAN, the absorption spectra Yang obtained for the PFs stood out immediately. The differences were greatest in PFs incorporating a carbon-oxygen functional group (carbonyl).

"We had the experimental evidence," says Yang, "but to understand what we were seeing, and its relevance to the conductivity of the polymer, we needed a theoretical explanation, starting from first principles." He asked Lin-Wang Wang of Berkeley Lab's Materials Sciences Division (MSD) to join the research collaboration.

Wang and his postdoctoral fellow, Nenad Vukmirovic, conducted ab initio calculations of the promising polymers at the Lab's National Energy Research Scientific Computing Center (NERSC). Wang says, "The calculation tells you what's really going on - including precisely how the lithium ions attach to the polymer, and why the added carbonyl functional group improves the process. It was quite impressive that the calculations matched the experiments so beautifully."

The simulation did indeed reveal "what's really going on" with the type of PF that includes the carbonyl functional group, and showed why the system works so well. The lithium ions interact with the polymer first, and afterward bind to the silicon particles. When a lithium atom binds to the polymer through the carbonyl group, it gives its electron to the polymer - a doping process that significantly improves the polymer's electrical conductivity, facilitating electron and ion transport to the silicon particles.

Cycling for success

"This achievement provides a rare scientific showcase, combining advanced tools of synthesis, characterization, and simulation in a novel approach to materials development," says Zahid Hussain, the ALS Division Deputy for Scientific Support and Scientific Support Group Leader. "The cyclic approach can lead to the discovery of new practical materials with a fundamental understanding of their properties."

The icing on the anode cake is that the new PF-based anode is not only superior but economical. "Using commercial silicon particles and without any conductive additive, our composite anode exhibits the best performance so far," says Gao Liu. "The whole manufacturing process is low cost and compatible with established manufacturing technologies. The commercial value of the polymer has already been recognized by major companies, and its possible applications extend beyond silicon anodes."

Anodes are a key component of lithium-ion battery technology, but far from the only challenge. Already the research collaboration is pushing to the next step, studying other battery components including cathodes.

###

"Polymers with Tailored Electronic Structure for High Capacity Lithium Battery Electrodes," by Gao Liu, Shidi Xun, Nenad Vukmirovic, Xiangyun Song, Paul Olalde-Velasco, Honghe Zheng, Vince S. Battaglia, Lin-Wang Wang, and Wanli Yang, appears in Advanced Materials and is available online at http://onlinelibrary.wiley.com/doi/10.1002/adma.201102421/abstract.

Materials research for this work in the BATT program was supported by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy. The ALS, NCEM, and NERSC are national scientific user facilities supported by DOE's Office of Science.

The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov.

For more about BATT, visit http://batt.lbl.gov/. For more about the ALS, go to http://www-als.lbl.gov/. For more about NCEM, see http://ncem.lbl.gov/. More about NERSC is at http://www.nersc.gov/.

Scientists have developed the first comprehensive catalog of the genetic aberrations responsible for an aggressive type of ovarian cancer that accounts for 70 percent of all ovarian cancer deaths.

Hundreds of researchers from more than 80 institutions, including scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), deciphered the genome structure and gene expression patterns in high-grade serous ovarian adenocarcinomas from almost 500 patients. They also sequenced the protein-coding part of the genome in about 320 of these patients. The result is the most expansive genomic analysis of any cancer to date and a major step toward the personalized treatment of ovarian cancer. The research is described in the June 30 issue of the journal Nature.

Their work could lead to a day in which doctors treat high-grade serous ovarian cancer by detecting the aberrant genes in a patient, and targeting these genes with therapies that are most effective against the specific mutations. It could also guide the development of new pharmaceuticals that are specially tailored to fight mutations that cause ovarian cancer.

The project was conducted under the auspices of the The Cancer Genome Atlas, an effort led by the National Institutes of Health’s National Cancer Institute and National Human Genome Research Institute to improve cancer care by understanding the genetic causes of the disease.

Paul Spellman of Berkeley Lab’s Life Sciences Division is the corresponding author of the Nature article. Several other Berkeley Lab scientists contributed to the research, including renowned cancer researcher Joe Gray, a guest senior scientist in Berkeley Lab’s Life Sciences Division. The project required collaboration among experts across the nation in tissue analysis, genome sequencing, cancer genomics, and data analysis.

“The Cancer Genome Atlas is about giving a parts list to the cancer community. Clinicians can use the data to propel the next wave of discoveries, such as new cancer therapies and early-detection methods,” says Spellman. “We are the first to systematically catalog the genetic mutations associated with ovarian cancer.”

Ovarian cancer is the fifth leading cause of cancer death among women in the U.S., with almost 22,000 new cases and 14,000 deaths estimated for 2010 according to the National Cancer Institute. High-grade serous ovarian cancer, which begins in the cells on the surface of the ovary, accounts for 90 percent of all ovarian cancers and often remains undetected until it’s quite advanced.

The standard of care is aggressive surgery followed by platinum-taxane chemotherapy. After therapy, however, platinum-resistant cancer recurs in approximately 25 percent of patients within six months and the overall 5-year survival rate is 31 percent. Because of this, scientists are seeking potent and targeted ways to fight the disease, which requires a thorough understanding of its genetic roots.

To do this, The Cancer Genome Atlas program brought together scientists from a wide range of disciplines and research institutions. More than two dozen sites provided tissue samples of ovarian tumors. Scientists at other sites performed gene expression analysis, DNA sequencing, and other analyses. The resulting data was fed to two repositories and analyzed by members of the network including Berkeley Lab scientists.

Among their many findings, the team determined that the causes of ovarian cancer are not confined to changes affecting individual genes. Large structural changes in a cancer’s genome — in which genes are erroneously deleted or duplicated — are also important. Scientists knew that ovarian cancer genomes have gene copy errors, but they didn’t know these hiccups are such a big driver of the disease.

They also found a possible new front in the fight against ovarian cancer. They tallied a group of about 30 gene mutations that plays a role in the disease, but which individually occur in only 1 to 2 percent of patients. A small number of patients had mutations of the BRAF gene. Another small subset had mutations of the Rb2 gene, which is common in breast cancer but not in ovarian cancer. And yet another subset had a mutation in a gene that codes for the production of the PI 3-kinase enzyme.

These mutations are quite rare by themselves, but together they’re found in almost 20 percent of ovarian cancer patients. Therapies already exist for many of these mutations, such as an inhibitor that silences the BRAF mutation, and others are in development.

“These are actionable rare events,” says Spellman. “They are very specific mutations that, if detected, clinicians can possibly go after — which opens up a whole new way to fight the disease.”

They also determined that a network of genes that repairs damaged DNA is defective in about half the tumors. Patients with this defect may benefit from therapies that inhibit this errant function. And they found that the spectrum of mutations in high-grade serous ovarian cancer is distinct from three other ovarian cancer subtypes, which are themselves distinct from each other.

“This represents an opportunity to improve cancer care by approaching the treatment of each subtype differently,” says Spellman.

Other findings include the fact that almost all patients with high-grade serous ovarian cancers have a mutation in the TP53 gene, which codes for a tumor-suppressing protein. This buttresses earlier research that underscored the importance of the TP53 gene mutation in ovarian cancer. In addition, almost a quarter of patients had BRCA1 or BRCA2 gene mutations, which also reaffirms earlier research.

This research was supported by the National Institutes of Health. In addition to the ovarian cancer study, The Cancer Genome Atlas is conducting large-scale genomic analyses of 19 other types of cancer, which are chosen in part because of their public health impact and poor prognosis.

For confirmation, see the State of the Nation, 2008, Canada's Science, Technology and Innovation System prepared under the auspices of the then-chair of Canada's Technology and Innovation System, Dr. Howard Alper. See www.stic-csti.ca for the full paper.

Concern 3

Venture Capital investment into Canada has been collapsing at an average rate of 14% per annum on a cumulative basis over the last eight years.

This discouraging statistic means that in these years the ability of displaced high-tech workers to start new companies has been progressively and profoundly impaired. This is of great concern if we have a sincere desire to replace the business R&D expended by Nortel each year in Canada. In 2008 the Nortel annual investment in Canada had declined $2B from its investments in the year 2000. This gap has remained unfilled, even with the emergence of new stars like RIM. The gap also accounts almost completely for the decline noted in business R&D to GDP Ratio (BERD) over that period. In short, no company has or is stepping into the spot made vacant by the reduction in investments by Nortel.

Concern 4

The loss in leadership in Broadband Network provision and performance.

In this highly competitive world, according to OECD measures (2008) we are currently rated: 10th in broadband penetration (29 subscribers per 100 inhabitants); 25th in terms of download speed (6.236 Mb/s); and have the 3rd highest average broadband monthly price per advertised Mb/s (26.11 USD, PPP ).

This is particularly alarming when you consider that Canada made an early start with broadband delivery and in 2001 had one of the highest broadband population penetrations in the world.

Most modern countries in the world have declared their strategies for sweeping advancements in Broadband Network deployments. Some in fact have already started. In South Korea and Japan for example, for every dollar invested there is an economic return of 4:1 minimum and in President Obama's stimulus program, he claimed a 10:1 leverage for every dollar invested in serving the underserved communities in the USA.

Reference The Need for Speed, ITIF March 2009

Concern 5

Academia is highly dependent upon the existence of a vibrant and thriving business sector.

Business, and in particular Nortel has been a key driver of university science and technology transformation. Nortel, in fact has recruited significant proportions of graduate calibre people from Canadian Universities. It has created Research Chairs across Canada and it has worked with Government to create programs like ATOP (Access to Opportunities) which subsequently has helped hundreds, if not thousands of students develop their careers and become contributing members of Canadian society. Who will fill Nortel's shoes? I know that this is of great concern to Canadian Academia.

Cumulative Effect

The cumulative impact of these concerns will create a huge negative thrust that could easily and irreversibly relegate Canada significantly in world standings and deny prosperity to our own and our childrens' futures. Canada cannot stand still whilst all of the above is happening.

The time to act is now and the first act must be to consider the national importance of all our key, innovative companies and the role they play in creating the incubation of new companies through their alumni and in creating new innovative firsts for Canada that can be exported across the globe.

I am aware that there are stimulus funds available to help sectors in industry, particularly in areas of infrastructure. It is time for for the Federal and Provincial levels of Government to take decisive action by putting a key stake in the ground by announcing that there is real, internationally competitive, tangible support available to build a world-class Broadband Infrastructure across Canada. This initiative would help protect Canadian innovations; spur the incubation of new ideas for the future prosperity of Canada; and engage industry in helping secure Canada's future and standard of living for all Canadians.

On the Nortel specific front, although consideration should still be given to "saving" some incarnation of Nortel and keeping it in Canadian hands, as a minimum it is critical that you at least to retain Nortel's intellectual property for Canada's exploitation (because much of it has been supported by ITCs over the years effectively giving every tax-paying Canadian a stake in the IPR).

It is now time to reverse the trend of being an incubator for foreign countries and for Canada, once again, to be a proud strong nation embracing innovation and generating prosperity for its citizens of today and for those of our future generations.