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  • richardmitnick 5:35 am on September 6, 2016 Permalink | Reply
    Tags: , Carbon nanotube transistors, , , U Wisconsin-Madison   

    From U Wisconsin: “First time, carbon nanotube transistors outperform silicon” 

    U Wisconsin

    University of Wisconsin

    September 2, 2016
    Adam Malecek

    1
    The UW–Madison engineers use a solution process to deposit aligned arrays of carbon nanotubes onto 1 inch by 1 inch substrates. The researchers used their scalable and rapid deposition process to coat the entire surface of this substrate with aligned carbon nanotubes in less than 5 minutes. The team’s breakthrough could pave the way for carbon nanotube transistors to replace silicon transistors, and is particularly promising for wireless communications technologies. Stephanie Precourt

    For decades, scientists have tried to harness the unique properties of carbon nanotubes to create high-performance electronics that are faster or consume less power — resulting in longer battery life, faster wireless communication and faster processing speeds for devices like smartphones and laptops.

    But a number of challenges have impeded the development of high-performance transistors made of carbon nanotubes, tiny cylinders made of carbon just one atom thick. Consequently, their performance has lagged far behind semiconductors such as silicon and gallium arsenide used in computer chips and personal electronics.

    Now, for the first time, University of Wisconsin–Madison materials engineers have created carbon nanotube transistors that outperform state-of-the-art silicon transistors.

    Led by Michael Arnold and Padma Gopalan, UW–Madison professors of materials science and engineering, the team’s carbon nanotube transistors achieved current that’s 1.9 times higher than silicon transistors. The researchers reported their advance in a paper published Friday (Sept. 2) in the journal Science Advances.

    “This achievement has been a dream of nanotechnology for the last 20 years,” says Arnold. “Making carbon nanotube transistors that are better than silicon transistors is a big milestone. This breakthrough in carbon nanotube transistor performance is a critical advance toward exploiting carbon nanotubes in logic, high-speed communications, and other semiconductor electronics technologies.”

    This advance could pave the way for carbon nanotube transistors to replace silicon transistors and continue delivering the performance gains the computer industry relies on and that consumers demand. The new transistors are particularly promising for wireless communications technologies that require a lot of current flowing across a relatively small area.

    As some of the best electrical conductors ever discovered, carbon nanotubes have long been recognized as a promising material for next-generation transistors.

    Carbon nanotube transistors should be able to perform five times faster or use five times less energy than silicon transistors, according to extrapolations from single nanotube measurements. The nanotube’s ultra-small dimension makes it possible to rapidly change a current signal traveling across it, which could lead to substantial gains in the bandwidth of wireless communications devices.

    But researchers have struggled to isolate purely carbon nanotubes, which are crucial, because metallic nanotube impurities act like copper wires and disrupt their semiconducting properties — like a short in an electronic device.

    The UW–Madison team used polymers to selectively sort out the semiconducting nanotubes, achieving a solution of ultra-high-purity semiconducting carbon nanotubes.

    “We’ve identified specific conditions in which you can get rid of nearly all metallic nanotubes, where we have less than 0.01 percent metallic nanotubes,” says Arnold.

    Placement and alignment of the nanotubes is also difficult to control.

    To make a good transistor, the nanotubes need to be aligned in just the right order, with just the right spacing, when assembled on a wafer. In 2014, the UW–Madison researchers overcame that challenge when they announced a technique, called “floating evaporative self-assembly,” that gives them this control.

    The nanotubes must make good electrical contacts with the metal electrodes of the transistor. Because the polymer the UW–Madison researchers use to isolate the semiconducting nanotubes also acts like an insulating layer between the nanotubes and the electrodes, the team “baked” the nanotube arrays in a vacuum oven to remove the insulating layer. The result: excellent electrical contacts to the nanotubes.

    The researchers also developed a treatment that removes residues from the nanotubes after they’re processed in solution.

    “In our research, we’ve shown that we can simultaneously overcome all of these challenges of working with nanotubes, and that has allowed us to create these groundbreaking carbon nanotube transistors that surpass silicon and gallium arsenide transistors,” says Arnold.

    The researchers benchmarked their carbon nanotube transistor against a silicon transistor of the same size, geometry and leakage current in order to make an apples-to-apples comparison.

    They are continuing to work on adapting their device to match the geometry used in silicon transistors, which get smaller with each new generation. Work is also underway to develop high-performance radio frequency amplifiers that may be able to boost a cellphone signal. While the researchers have already scaled their alignment and deposition process to 1 inch by 1 inch wafers, they’re working on scaling the process up for commercial production.

    Arnold says it’s exciting to finally reach the point where researchers can exploit the nanotubes to attain performance gains in actual technologies.

    “There has been a lot of hype about carbon nanotubes that hasn’t been realized, and that has kind of soured many people’s outlook,” says Arnold. “But we think the hype is deserved. It has just taken decades of work for the materials science to catch up and allow us to effectively harness these materials.”

    The researchers have patented their technology through the Wisconsin Alumni Research Foundation.

    Funding from the National Science Foundation, the Army Research Office and the Air Force supported their work.

    Additional authors on the paper include Harold Evensen, a University of Wisconsin-Platteville engineering physics professor, Gerald Brady, a UW–Madison materials science and engineering graduate student and lead author on the study, and graduate student Austin Way and postdoctoral researcher Nathaniel Safron.

    See the full article here .

    Please help promote STEM in your local schools.

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    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 10:07 am on August 4, 2016 Permalink | Reply
    Tags: , , , U Wisconsin-Madison   

    From U Wisconsin: “Tiny high-performance solar cells turn power generation sideways” 

    U Wisconsin

    University of Wisconsin

    August 3, 2016
    Sam Million-Weaver

    1
    Hongrui Jiang inspects the alignment of a light source to illuminate new-generation lateral solar cells. The solar cells developed by Jiang’s group harvest almost three times more electricity from incoming light as compared to existing technologies. Photo: Stephanie Precourt

    University of Wisconsin—Madison engineers have created high-performance, micro-scale solar cells that outshine comparable devices in key performance measures. The miniature solar panels could power myriad personal devices — wearable medical sensors, smartwatches, even autofocusing contact lenses.

    Large, rooftop photovoltaic arrays generate electricity from charges moving vertically. The new, small cells, described today (Aug. 3, 2016) in the journal Advanced Materials Technologies, capture current from charges moving side-to-side, or laterally. And they generate significantly more energy than other sideways solar systems.

    New-generation lateral solar cells promise to be the next big thing for compact devices because arranging electrodes horizontally allows engineers to sidestep a traditional solar cell fabrication process: the arduous task of perfectly aligning multiple layers of the cell’s material atop one another.

    “From a fabrication point of view, it is always going to be easier to make side-by-side structures,” says Hongrui Jiang, a UW–Madison professor of electrical and computer engineering and corresponding author on the paper. “Top-down structures need to be made in multiple steps and then aligned, which is very challenging at small scales.”

    Lateral solar cells also offer engineers greater flexibility in materials selection.

    Top-down photovoltaic cells are made up of two electrodes surrounding a semiconducting material like slices of bread around the meat in a sandwich. When light hits the top slice, charge travels through the filling to the bottom layer and creates electric current.

    In the top-down arrangement, one layer needs to do two jobs: It must let in light and transmit charge. Therefore, the material for one electrode in a typical solar cell must be not only highly transparent, but also electrically conductive. And very few substances perform both tasks well.

    Instead of building its solar cell sandwich one layer at a time, Jiang’s group created a densely packed, side-by-side array of miniature electrodes on top of transparent glass. The resulting structure — akin to an entire loaf of bread’s worth of solar-cell sandwiches standing up sideways on a clear plate — separates light-harvesting and charge-conducting functions between the two components.

    Generally, synthesizing such sideways sandwiches is no simple matter. Other approaches that rely on complicated internal nanowires or expensive materials called perovskites fall short on multiple measures of solar cell quality.

    “We easily beat all of the other lateral structures,” says Jiang.

    Existing top-of the-line lateral new-generation solar cells convert merely 1.8 percent of incoming light into useful electricity. Jiang’s group nearly tripled that measure, achieving up to 5.2 percent efficiency.

    “In other structures, a lot of volume goes wasted because there are no electrodes or the electrodes are mismatched,” says Jiang. “The technology we developed allows us to make very compact lateral structures that take advantage of the full volume.”

    Packing so many electrodes into such a small volume boosted the devices’ “fill factors,” a metric related to the maximum attainable power, voltage and current. The structures realized fill factors up to 0.6 — more than twice the demonstrated maximum for other lateral new-generation solar cells.

    Jiang and colleagues are working to make their solar cells even smaller and more efficient by exploring materials that further optimize transparency and conductivity. Ultimately they plan to develop a small-scale, flexible solar cell that could provide power to an electrically tunable contact lens.

    Other authors on the paper included Xi Zhang, Yinggang Huang, Hao Bian, Hewei Liu, and Xuezhen Huang. The National Institutes of Health provided funding for the research.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 4:46 pm on July 25, 2016 Permalink | Reply
    Tags: 3-D printing, , , , U Wisconsin-Madison   

    From U Wisconsin: “Tiny 3-D models may yield big insights into ovarian cancer” 

    U Wisconsin

    University of Wisconsin

    July 25, 2016
    Will Cushman
    perspective@engr.wisc.edu

    With a unique approach that draws on 3-D printing technologies, a team of University of Wisconsin–Madison researchers is developing new tools for understanding how ovarian cancer develops in women.

    About 1.5 percent of American women will be diagnosed with ovarian cancer, but most of them will not be diagnosed until late in the disease’s progression — after the cancer has spread to other parts of the body. This is reflected in the grim outlook for most women: The five-year survival rate for ovarian cancer is about 25 percent.

    Paul Campagnola, a professor of biomedical engineering and medical physics at UW–Madison, leads a group of researchers aiming to improve that outlook by understanding how ovarian cancer cells interact with nearby body tissue, and by developing new tools for imaging and detecting the disease. With a $2 million grant from the National Institutes of Health, they will use technology they’ve developed on the UW–Madison campus to develop images of tissues from surgical patients. The first target is collagen, a common protein that gives much of the body structure by holding bones, ligaments and muscles together.

    1
    A normal ovarian epithelial cell clings to a tiny model of an ovarian cancer tumor made with a 3-D printer. The tumor models will help scientists study ovarian cancer in mice, which do not naturally develop the disease. Image courtesy of Paul Campagnola

    “In most cancers, including ovarian, there are large changes in the collagen structure that goes along with the disease,” Campagnola says. “It might happen first. It might be later. It’s actually not known.”

    Campagnola and his colleagues, including Kevin Eliceiri, director of UW–Madison’s Laboratory for Optical and Computational Instrumentation, and Manish Patankar, associate professor of obstetrics and gynecology, hope to eliminate that unknown by printing tiny, 3-D models of the collagen samples.

    The models will be biomimetic — synthetic, but mimicking biological materials, as Velcro mimics the burs of a plant — and extremely small. Because, after seeding the models with ovarian cancer cells, the researchers will implant them into mice.

    Why not simply inject the mice with cancer cells and skip the painstaking imaging and 3-D printing process? Mice don’t get ovarian cancer — a partial answer for why we still don’t understand ovarian cancer as well as many other cancers.

    “The current way that people study ovarian cancer in a mouse is very poor,” Campagnola explains. “They just take human cell lines and then inject them into a mouse. Then some of them will form into a tumor, but most do not.”

    By implanting a 3-D tissue model seeded with ovarian cancer into mice, Campagnola hopes to mimic more closely the conditions of metastatic ovarian cancer in humans.

    “What’s different is our tissues will already be 3-D structured,” Campagnola says. “One problem when people study cancer sometimes is that they put cells in a dish. Cells in a dish don’t act like cells in tissue. So we’re trying to give them the tissue structure that cancer cells would have in a native environment.”

    From there, they’ll study how the implanted tumors grow inside the mice, and hopefully begin to learn more about the cues and processes involved in the disease’s progression and spread.

    It’s an approach that no one has ever attempted, one that will also help improve the way doctors make images of ovaries inside the body.

    “It’s an integrated approach to improving our imaging capabilities, but then also using our imaging capabilities to make these models so we can study the biology,” Campagnola says.

    Ultimately, the team’s long-term goal is to improve screening, diagnosis and treatment of ovarian cancer. One of the most effective ways to improve the outlook for women with ovarian cancer is to develop a straightforward method for screening women at higher risk for the disease. Women with a mutation in a gene called BRCA — a mutation also implicated in a higher risk for breast cancer — have a 40 percent chance of developing ovarian cancer in their lifetime.

    “Those are the women we really want to follow,” Campagnola says. “You could imagine — we’re a long way off from this — screening those women every few years with a minimally invasive device through a laparoscope or through the fallopian tubes.”

    But to get to that point, Campagnola says, researchers need to know a lot more about how ovarian cancer works.

    “You have to know what you’re looking for,” he says. “That’s why we have all this more basic work to do to get to that point. That’s why we need better imaging tools and we need better models to understand the biology of the disease.”

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 5:44 am on July 23, 2016 Permalink | Reply
    Tags: , , , U Wisconsin-Madison   

    From U Wisconsin: “New UW-Madison center offers ultra-speed protein analysis” 

    U Wisconsin

    University of Wisconsin

    July 22, 2016
    David Tenenbaum
    djtenenb@wisc.edu

    1
    UW-Madison undergraduate Kyle Connors operates a mass spectrometer in the new NIH National Center for Quantitative Biology at UW–Madison. Photo: Nick Wilkes

    Three University of Wisconsin—Madison researchers have won a prestigious, five-year grant to establish the National Center for Quantitative Biology of Complex Systems, which will develop next-generation protein measurement technologies and offer them to biologists nationwide.

    It is proteins that do the work in the body: Hemoglobin, for example, holds oxygen for transport in the blood stream, while insulin helps regulate sugar in the blood. Knowing which protein forms are present in what quantities, their subcellular location and their function is critical to understanding health and disease.

    The scientific technique of mass spectrometry, or mass spec, can already recognize proteins, but the researchers are eying a speed-up akin to that which revolutionized genetics research over the past 20 years.

    Genes are vital carriers of information and templates for proteins, says co-investigator David Pagliarini, a UW–Madison professor of biochemistry. But genes alone don’t explain everything.

    There is lot of action between the gene, the protein it patterns, and the actual biological result,” he explains. “Mass spec technology allows you to measure the proteins, which are closer to action, and we plan to push the limits on pace, depth, throughput.”

    The center, funded at $6 million by the National Institutes of Health (NIH), will develop and make available advanced protein measurement technologies, says Josh Coon, a UW–Madison professor of biomolecular chemistry and an expert in mass spec. “These are complicated, high-end instruments that hundreds or thousands of biomedical researchers who are funded by the NIH need access to. There are many problems that are not solved with current technology, and that high-throughput mass spec can address.”

    2
    A modified orbitrap mass spectrometer in the Coon Laboratory. The modifications illuminate trapped protein ions with infrared photons, providing the basis of a new protein sequencing technology. Photo: Nick Wilkes

    Two among the many areas of interest concern lung cancer and diabetes, Coon says. “We have researchers who want to examine proteins related to the function — or failure — of the pancreatic cells that make insulin.”

    The center will serve as a training ground in mass spec and a laboratory to invent new techniques and equipment. One tactic to be explored relies on parallel processing, an approach like the one that fed a revolution in gene sequencing.

    Co-investigator Lingjun Li, a UW–Madison professor of pharmacy, will develop chemical markers to identify individual samples after they are mixed for mass spec analysis. In a similar vein, Coon will explore “metabolic tags” composed of amino acids that enter proteins after being eaten by lab animals.

    “We are not developing technology in a vacuum,” says Li, “but with specific biomedical needs in mind. Our methods will be broadly available to NIH researchers, and they will be the test bed that validates our methods.”

    Pagliarini says he will serve as “a bridge between technology development and biological applications. Our future collaborators have told us there are certain problem out there waiting for a solution in new technology.”

    “The NIH wants the center to invent and disseminate technologies,” says Coon. “We hope to do for proteins what high-throughput sequencing has done for genomic studies.”

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 11:32 am on June 9, 2016 Permalink | Reply
    Tags: , , Chemistry lessons from bacteria may improve biofuel production, U Wisconsin-Madison   

    From Wisconsin: “Chemistry lessons from bacteria may improve biofuel production” 

    U Wisconsin

    University of Wisconsin

    June 8, 2016
    Chris Barncard

    If you’re made of carbon, precious few things are as important to life as death.

    A dead tree may represent a literal windfall of the building blocks necessary for making new plants and animals and the energy to sustain them.

    “The recycling of plant carbon is fundamental to the function of our ecosystems,” says Cameron Currie, professor of bacteriology at the University of Wisconsin–Madison. “We get food, water, air, energy — almost everything — through those ecosystem services. It’s how our planet operates.”

    But the component parts of a dead tree were carefully assembled in the first place, and don’t just fall apart for easy recycling.

    1
    The ability to break down the cellulose in plant material is rare in Streptomyces bacteria, except in strains that live alongside insects — honeybees, leaf-cutter ants (above), some beetles —that eat or make use of the woody parts of plants. Courtesy of Don Parsons/UW-Madison

    In the case of cellulose — a key structural component in plant cell walls and the most abundant organic compound in life on land — a world of specialized microbes handles this careful deconstruction. Much of that work is done by fungi growing on decaying plants, but bacteria in the soil, in the guts of animals like cows and working alongside insects, get the job done, too.

    A new analysis of a group of bacteria called Streptomyces reveals the way some strains of the microbe developed advanced abilities to tear up cellulose, and points out more efficient ways we might mimic those abilities to make fuel from otherwise unusable plant material.

    Streptomyces were long thought to be prominent contributors at work in breaking down cellulose, and to be equally active in the cause across hundreds or thousands of strains of the bacteria.

    2
    Researchers tried to grow different strains of Streptomyces bacteria on dead plant material (in this case, filter paper). Successful cellulose processing strains tapped special genes to produce enzymes that break down cellulose. Courtesy of Currie Lab/UW-Madison

    “The strains that aren’t good at degrading cellulose mostly express the same genes whether we grow them on glucose or on plant material,” says Gina Lewin, a bacteriology graduate student and study co-author. “The strains that are really good at degrading cellulose totally change their gene expression when we grow them on plant material.”

    The successful Streptomyces strains — which were typically those found living in communities with insects — ramp up production of certain enzymes, the proteins that do the cleaving and dissolving and picking apart of cellulose.

    “There are families — six or eight or maybe 10 of these enzymes — that all of the active Streptomyces have,” Fox says. “And this paper shows that the most abundant one of them has to be there or the whole thing collapses.”

    It’s the particular combinations of enzymes that makes the research useful to scientists working on biofuels.

    4
    Counter to long-held belief about the bacteria Streptomyces, seen growing here in a petri dish, the ability to break down a stubborn molecule in plant cell walls called cellulose may be limited to just a few gifted strains. Courtesy of Adam Book/UW-Madison

    Biofuels are typically made from the sugars easily extracted from the same parts of plants we eat.

    “We eat the kernels off the corn cob,” Currie says. “But most of the energy in that corn plant is in the part which is not digestible to us. It’s not in the cob. It’s in the green parts, like the stalk and the leaves.”

    Evolving microbes like Streptomyces have been sharpening the way they make use of those parts of plants almost as long as the plants themselves have been growing on land. That’s hundreds of millions of years. On the other hand, the Department of Energy’s UW–Madison-based Great Lakes Bioenergy Research Center, which funded the Streptomyces study, was established in 2007.

    “The natural world is responding to the same kind of things that humans are,” Fox says. “We need to get food. We need to get energy. And different types of organisms are achieving their needs in different ways. It’s worth looking at how they do it.”

    The new study identifies important enzymes, and new groups of enzymes, produced when Streptomyces flex particular genes. If they represent an improvement over current industrial processes, the microbes’ tricks could make for a great boon to bioenergy production.

    “For a cellulosic biofuel plant, enzymes are one of the most expensive parts of making biofuels,” Lewin says. “So, if you can identify enzymes that work even just slightly better, that could mean a difference of millions of dollars in costs and cheaper energy.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 12:49 am on January 23, 2016 Permalink | Reply
    Tags: , Radiation device callibration, U Wisconsin-Madison   

    From Wisconsin: “Lab keeps cancer treatment radiation machines honest” 

    U Wisconsin

    University of Wisconsin

    January 22, 2016
    David Tenenbaum

    As radiation sources used to map disease and attack cancer grow in number and complexity, a University of Wisconsin—Madison center continues to offer the last word on accurate radiation doses.

    From its headquarters in the basement of the Wisconsin Institutes for Medical Research, the University of Wisconsin Radiation Calibration Laboratory fine-tunes instruments used by clinics to measure radiation doses from X-ray machines, CAT scanners and medical linear accelerators used to treat cancer.

    Temp 1
    Larry DeWerd, a professor of medical physics at UW–Madison, directs the University of Wisconsin Radiation Calibration Laboratory, which tests and calibrates radiation-measurement devices from around the nation and beyond. Photos: David Tenenbaum

    “We are one of three institutions in the United States that base our accuracy on devices verified by NIST (the National Institute of Standards and Technology),” says director Larry DeWerd, a UW–Madison professor of medical physics. “And we provide calibration to approximately 60 percent of the U.S. medical physics market.”

    By measuring an unknown instrument against a known one, the process of calibration creates a correction factor that clinics can use to ensure safety and accuracy of the dose, says DeWerd.

    DeWerd, who received his doctorate from UW–Madison and has worked at the lab since its inauguration in 1981, credits John Cameron, founder of the world’s largest department of medical physics at UW–Madison, with help in the startup. “I was talking with him about a calibration lab, and he thought it was a great idea.”

    The lab has a full set of equipment, such as radiation sources and calibration devices, 10 employees and 15 graduate students. “Our students get a hands-on opportunity to do research and work in the lab,” says DeWerd. “We provide education to users as well as calibrate their devices. We do charge fees for our calibration services, and most of the graduate student research is supported by fee income.”

    As radiation sources evolve, “we need to ask questions so these new devices can be used safely and effectively,” DeWerd says. “The organizations and clinics that buy calibrations from us are funding necessary research while they get a service that’s only available from two other sources in the nation.”

    The high-energy photons created by X-ray machines, CAT scanners, medical linear accelerators and radioactive decay are called ionizing radiation because they can strip away electrons to ionize atoms. Medical radiation is measured by sophisticated ionization chambers that create an electrical current when exposed to the ionizing radiation. This electrical current is read out by an electric meter that can provide the radiation dose.

    To begin a calibration study, the lab measures a beam of radiation using a chamber that has been calibrated at NIST and is accurate to within 0.5 percent. Then clinical medical physicists place chambers owned by clinics, hospitals or cancer centers in the beam.

    “We first measure with our chamber, which has been tested at NIST, and then measure their chamber in the exact same beam,” says DeWerd. “If our chamber measures 100 units, and their chamber measures 105, that establishes the correction factor they must use to obtain an accurate measurement from their chamber.”

    After being returned to its owner, a calibrated chamber may be used for two years before recalibration is needed.

    Half a century or so ago, the dosage from X-ray machines and accelerators could vary significantly, DeWerd says. Although calibration has changed all that, innovations in medical systems continue to overturn the field. One significant advance comes from steerable radiation treatment machines like the TomoTherapy machine. This device, invented at UW–Madison and still manufactured in Madison, “shapes” a beam and “shoots” it at multiple angles. Both measures are intended to reduce damage to healthy tissue while tumors are irradiated.

    External radiation beams are not the only sources needing calibration. Lab researchers have also been calibrating an innovative sheet radiation source designed to treat multiple cancer sites. Continual advances in brachytherapy — the placement of small, contained sources of radioactive isotopes inside the body to treat cancer — also raise research questions.

    Beyond servicing radiation oncology and radiology clinics around the nation and far beyond, the lab calibrates for some of the UW–Madison spinoffs that sell calibration devices to industry. These businesses, like the lab itself, trace their roots back to John Cameron.

    “Our emphasis is standards; making measurements and tracing them back to the primary numbers from NIST,” DeWerd says. “We also work closely with NIST. Sometimes we do original research and pass it on to them. Or they do the research, and we put their results to work for us.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 8:25 am on September 15, 2015 Permalink | Reply
    Tags: , , U Wisconsin-Madison   

    From Wisconsin: “Discovery of a highly efficient catalyst eases way to hydrogen economy” 

    U Wisconsin

    University of Wisconsin

    Sept. 14, 2015
    David Tenenbaum

    1
    Bathed in simulated sunlight, this photoelectrolysis cell in the lab of Song Jin splits water into hydrogen and oxygen using a catalyst made of the abundant elements cobalt, phosphorus and sulfur. Photos: David Tenenbaum

    Hydrogen could be the ideal fuel: Whether used to make electricity in a fuel cell or burned to make heat, the only byproduct is water; there is no climate-altering carbon dioxide.

    Like gasoline, hydrogen could also be used to store energy.

    Hydrogen is usually produced by separating water with electrical power. And although the water supply is essentially limitless, a major roadblock to a future “hydrogen economy” is the need for platinum or other expensive noble metals in the water-splitting devices.

    Noble metals resist oxidation and include many of the precious metals, such as platinum, palladium, iridium and gold.

    2
    Song Jin

    “In the hydrogen evolution reaction, the whole game is coming up with inexpensive alternatives to platinum and the other noble metals,” says Song Jin, a professor of chemistry at the University of Wisconsin-Madison.

    In the online edition of Nature Materials that appears today, Jin’s research team reports a hydrogen-making catalyst containing phosphorus and sulfur — both common elements — and cobalt, a metal that is 1,000 times cheaper than platinum.

    Catalysts reduce the energy needed to start a chemical reaction. The new catalyst is almost as efficient as platinum and likely shows the highest catalytic performance among the non-noble metal catalysts reported so far, Jin reports.

    The advance emerges from a long line of research in Jin’s lab that has focused on the use of iron pyrite (fool’s gold) and other inexpensive, abundant materials for energy transformation. Jin and his students Miguel Cabán-Acevedo and Michael Stone discovered the new high-performance catalyst by replacing iron to make cobalt pyrite, and then added phosphorus.

    Although electricity is the usual energy source for splitting water into hydrogen and oxygen, “there is a lot of interest in using sunlight to split water directly,” Jin says.

    The new catalyst can also work with the energy from sunlight, Jin says. “We have demonstrated a proof-of-concept device for using this cobalt catalyst and solar energy to drive hydrogen generation, which also has the best reported efficiency for systems that rely only on inexpensive catalysts and materials to convert directly from sunlight to hydrogen.”

    Many researchers are looking to find a cheaper replacement for platinum, Jin says. “Because this new catalyst is so much better and so close to the performance of platinum, we immediately asked WARF (the Wisconsin Alumni Research Foundation) to file a provisional patent, which they did in just two weeks.”

    Many questions remain about a catalyst that has only been tested in the lab, Jin says. “One needs to consider the cost of the catalyst compared to the whole system. There’s always a tradeoff: If you want to build the best electrolyzer, you still want to use platinum. If you are able to sacrifice a bit of performance and are more concerned about the cost and scalability, you may use this new cobalt catalyst.”

    Strategies to replace a significant portion of fossil fuels with renewable solar energy must be carried out on a huge scale if they are to affect the climate crisis, Jin says. “If you want to make a dent in the global warming problem, you have to think big. Whether we imagine making hydrogen from electricity, or directly from sunlight, we need square miles of devices to evolve that much hydrogen. And there might not be enough platinum to do that.”

    The collaborative team included Professor J.R. Schmidt, a theoretical chemist at UW-Madison, and electrical engineering Professor Jr-Hau He and his students from King Abdullah University of Science and Technology in Saudi Arabia. The U.S. Department of Energy provided major funding for the study.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 2:52 pm on August 31, 2015 Permalink | Reply
    Tags: , , U Wisconsin-Madison   

    From Madison: “Sustainable Nanotechnology Center Lands New $20 Million Contract” 

    U Wisconsin

    University of Wisconsin

    08/31/201
    Terry Devitt

    1
    Two graduate students working with the Center for Sustainable Nanotechnology examine a vial in a chemistry laboratory

    The Center for Sustainable Nanotechnology, a multi-institutional research center based at the University of Wisconsin-Madison, has inked a new contract with the National Science Foundation (NSF) that will provide nearly $20 million in support over the next five years.

    Directed by UW-Madison chemistry Professor Robert Hamers, the center focuses on the molecular mechanisms by which nanoparticles interact with biological systems.

    Nanotechnology involves the use of materials at the smallest scale, including the manipulation of individual atoms and molecules. Products that use nanoscale materials range from beer bottles and car wax to solar cells and electric and hybrid car batteries. If you read your books on a Kindle, a semiconducting material manufactured at the nanoscale underpins the high-resolution screen.

    While there are already hundreds of products that use nanomaterials in various ways, much remains unknown about how these modern materials and the tiny particles they are composed of interact with the environment and living things.

    “The purpose of the center is to explore how we can make sure these nanotechnologies come to fruition with little or no environmental impact,” explains Hamers. “We’re looking at nanoparticles in emerging technologies.”

    In addition to UW-Madison, scientists from UW-Milwaukee, the University of Minnesota, the University of Illinois, Northwestern University and the Pacific Northwest National Laboratory have been involved in the center’s first phase of research. Joining the center for the next five-year phase are Tuskegee University, Johns Hopkins University, the University of Iowa, Augsburg College, Georgia Tech and the University of Maryland, Baltimore County.

    At UW-Madison, Hamers leads efforts in synthesis and molecular characterization of nanomaterials. Soil science Professor Joel Pedersen and chemistry Professor Qiang Cui lead groups exploring the biological and computational aspects of how nanomaterials affect life.

    Much remains to be learned about how nanoparticles affect the environment and the multitude of organisms — from bacteria to plants, animals and people — that may be exposed to them.

    “Some of the big questions we’re asking are: How is this going to impact bacteria and other organisms in the environment? What do these particles do? How do they interact with organisms?” says Hamers.

    For instance, bacteria, the vast majority of which are beneficial or benign organisms, tend to be “sticky” and nanoparticles might cling to the microorganisms and have unintended biological effects.

    “There are many different mechanisms by which these particles can do things,” Hamers adds. “The challenge is we don’t know what these nanoparticles do if they’re released into the environment.”

    To get at the challenge, Hamers and his UW-Madison colleagues are drilling down to investigate the molecular-level chemical and physical principles that dictate how nanoparticles interact with living things.

    Pedersen’s group, for example, is studying the complexities of how nanoparticles interact with cells and, in particular, their surface membranes.

    “To enter a cell, a nanoparticle has to interact with a membrane,” notes Pedersen. “The simplest thing that can happen is the particle sticks to the cell. But it might cause toxicity or make a hole in the membrane.”

    Pedersen’s group can make model cell membranes in the lab using the same lipids and proteins that are the building blocks of nature’s cells. By exposing the lab-made membranes to nanomaterials now used commercially, Pedersen and his colleagues can see how the membrane-particle interaction unfolds at the molecular level — the scale necessary to begin to understand the biological effects of the particles.

    Such studies, Hamers argues, promise a science-based understanding that can help ensure the technology leaves a minimal environmental footprint by identifying issues before they manifest themselves in the manufacturing, use or recycling of products that contain nanotechnology-inspired materials.

    To help fulfill that part of the mission, the center has established working relationships with several companies to conduct research on materials in the very early stages of development.

    “We’re taking a look-ahead view. We’re trying to get into the technological design cycle,” Hamers says. “The idea is to use scientific understanding to develop a predictive ability to guide technology and guide people who are designing and using these materials.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 2:47 pm on March 26, 2015 Permalink | Reply
    Tags: , , , U Wisconsin-Madison   

    From Wisconsin: “Ebola whole virus vaccine shown effective, safe in primates” 

    U Wisconsin

    University of Wisconsin

    March 26, 2015
    Terry Devitt

    1
    Ebola virus swarms the surface of a host cell in this electron micrograph. Like most viruses, Ebola requires the help of a host cell to survive and replicate. Photo: Takeshi Noda, University of Tokyo

    An Ebola whole virus vaccine, constructed using a novel experimental platform, has been shown to effectively protect monkeys exposed to the often fatal virus.

    The vaccine, described today (March 26, 2015) in the journal Science, was developed by a group led by Yoshihiro Kawaoka, a University of Wisconsin-Madison expert on avian influenza, Ebola and other viruses of medical importance. It differs from other Ebola vaccines because as an inactivated whole virus vaccine, it primes the host immune system with the full complement of Ebola viral proteins and genes, potentially conferring greater protection.

    “In terms of efficacy, this affords excellent protection,” explains Kawaoka, a professor of pathobiological sciences in the UW-Madison School of Veterinary Medicine and who also holds a faculty appointment at the University of Tokyo. “It is also a very safe vaccine.”

    The vaccine was constructed on an experimental platform first devised in 2008 by Peter Halfmann, a research scientist in Kawaoka’s lab. The system allows researchers to safely work with the virus thanks to the deletion of a key gene known as VP30, which the Ebola virus uses to make a protein required for it to reproduce in host cells. Ebola virus has only eight genes and, like most viruses, depends on the molecular machinery of host cells to grow and become infectious.

    By engineering monkey kidney cells to express the VP30 protein, the virus can be safely studied in the lab and be used as a basis for devising countermeasures like a whole virus vaccine. The vaccine reported by Kawaoka and his colleagues was additionally chemically inactivated using hydrogen peroxide, according to the new Science report.

    Ebola first emerged in 1976 in Sudan and Zaire. The current outbreak in West Africa has so far claimed more than 10,000 lives. There are no proven treatments or vaccines, although several vaccine platforms have been devised in recent years, four of which recently advanced to the clinical trial stage in humans.

    2
    Yoshihiro Kawaoka

    The new vaccine reported by Kawaoka has not been tested in people. However, the successful tests in nonhuman primates conducted at the National Institutes of Health (NIH) Rocky Mountain Laboratories, a biosafety level 4 facility in Hamilton, Montana, may prompt further tests and possibly clinical trials of the new vaccine. The work at Rocky Mountain Laboratories was conducted in collaboration with a group led by Heinz Feldmann of NIH.

    Those studies were conducted with cynomolgus macaques, which are very susceptible to Ebola. “It’s the best model,” Kawaoka says. “If you get protection with this model, it’s working.”

    Ebola vaccines currently in trials include:

    A DNA-based plasmid vaccine that primes host cells with some of the Ebola proteins.
    A vaccine based on a replication incompetent chimpanzee respiratory virus engineered to express a key Ebola protein.
    A live attenuated virus from the same family of viruses that causes rabies, also engineered to express a critical Ebola protein.
    A vaccine based on a vaccinia virus and engineered to express a critical Ebola protein.

    Each of those strategies, Kawaoka notes, has drawbacks in terms of safety and delivery.

    Whole virus vaccines have long been used to successfully prevent serious human diseases, including polio, influenza, hepatitis and human papillomavirus-mediated cervical cancer.

    The advantage conferred by inactivated whole virus vaccines such as the one devised by Halfmann, Kawaoka and their colleagues is that they present the complete range of proteins and genetic material to the host immune system, which is then more likely to trigger a broader and more robust immune response.

    Early attempts to devise an inactivated whole virus Ebola vaccine through irradiation and the preservative formalin failed to protect monkeys exposed to the Ebola virus and were abandoned.

    Although the new vaccine has surpassed that hurdle, human trials are expensive and complex, costing millions of dollars.

    The Ebola vaccine study conducted by Kawaoka was supported by the National Institutes of Health and by the Japanese Health and Labour Sciences Research Grants.

    In addition to Kawaoka, co-authors of the new Science report include Halfmann, Lindsay Hill-Batorski and Gabriele Neumann of UW-Madison and Andrea Marzi, W. Lesley Shupert and Feldmann of the National Institute of Allergy and Infectious Diseases.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 2:20 pm on December 13, 2014 Permalink | Reply
    Tags: , , , U Wisconsin-Madison   

    From Wisconsin: “New theory suggests alternate path led to rise of the eukaryotic cell” 

    U Wisconsin

    University of Wisconsin

    As a fundamental unit of life, the cell is central to all of biology. Better understanding how complex cells evolved and work promises new revelations in areas as diverse as cancer research and developing new crop plants.

    But deep thinking on how the eukaryotic cell came to be is astonishingly scant. Now, however, a bold new idea of how the eukaryotic cell and, by extension, all complex life came to be is giving scientists an opportunity to re-examine some of biology’s key dogma.

    All complex life — including plants, animals and fungi — is made up of eukaryotic cells, cells with a nucleus and other complex internal machinery used to perform the functions an organism needs to stay alive and healthy. Humans, for example, are composed of 220 different kinds of eukaryotic cells — which, working in groups, control everything from thinking and locomotion to reproduction and immune defense.

    Thus, the origin of the eukaryotic cell is considered one of the most critical evolutionary events in the history of life on Earth. Had it not occurred sometime between 1.6 and 2 billion years ago, our planet would be a far different place, populated entirely by prokaryotes, single-celled organisms such as bacteria and archaea.

    e
    Eukaryotes and some examples of their diversity

    p
    Cell structure of a bacterium, a member of one of the two domains of prokaryotic life

    a
    Halobacteria sp. strain NRC-1, each cell about 5 μm long

    For the most part, scientists agree that eukaryotic cells arose from a symbiotic relationship between bacteria and archaea. Archaea — which are similar to bacteria but have many molecular differences — and bacteria represent two of life’s three great domains. The third is represented by eukaryotes, organisms composed of the more complex eukaryotic cells.

    Eukaryotic cells are characterized by an elaborate inner architecture. This includes, among other things, the cell nucleus, where genetic information in the form of DNA is housed within a double membrane; mitochondria, membrane-bound organelles, which provide the chemical energy a cell needs to function; and the endomembrane system, which is responsible for ferrying proteins and lipids about the cell.

    d
    The structure of part of a DNA double helix

    m
    Two mitochondria from mammalian lung tissue displaying their matrix and membranes as shown by electron microscopy

    Prevailing theory holds that eukaryotes came to be when a bacterium was swallowed by an archaeon. The engulfed bacterium, the theory holds, gave rise to mitochondria, whereas internalized pieces of the outer cell membrane of the archaeon formed the cell’s other internal compartments, including the nucleus and endomembrane system.

    “The current theory is widely accepted, but I would not say it is ‘established’ since nobody seems to have seriously considered alternative explanations,” explains David Baum, a University of Wisconsin-Madison professor of botany and evolutionary biologist who, with his cousin, University College London cell biologist Buzz Baum, has formulated a new theory for how eukaryotic cells evolved. Known as the “inside-out” theory of eukaryotic cell evolution, the alternative view of how complex life came to be was published recently (Oct. 28, 2014) in the open access journal BMC Biology.

    cd

    The inside-out theory proposed by the Baums suggests that eukaryotes evolved gradually as cell protrusions, called blebs, reached out to trap free-living mitochondria-like bacteria. Drawing energy from the trapped bacteria and using bacterial lipids — insoluble organic fatty acids — as building material, the blebs grew larger, eventually engulfing the bacteria and creating the membrane structures that form the cell’s internal compartment boundaries.

    “The idea is tremendously simple,” says David Baum, who first began thinking about an alternate theory to explain the rise of the eukaryotic cell as an Oxford University undergraduate 30 years ago. “It is a radical rethinking, taking what we thought we knew (about the cell) and turning it inside-out.”

    From time to time, David Baum dusted off his rudimentary idea and shared it with others, including the late Lynn Margulis, the American scientist who developed the theory of the origin of eukaryotic organelles. Over the past year, Buzz and David Baum refined and detailed their idea, which, like any good theory, makes predictions that are testable.

    “First, the inside-out idea immediately suggested a steady stepwise path of evolution that required few cellular or molecular innovations. This is just what is required of an evolutionary model,” argues Buzz Baum, an expert on cell shape and structure. “Second, the model suggested a new way of looking at modern cells.”

    “The current theory is widely accepted, but I would not say it is ‘established’ since nobody seems to have seriously considered alternative explanations.”

    d
    David Baum

    Modern eukaryotic cells, says Buzz Baum, can be interrogated in the context of the new theory to answer many of their unexplained features, including why nuclear events appear to be inherited from archaea while other features seem to be derived from the bacteria.

    “It is refreshing to see people thinking about the cell holistically and based on how cells and organisms evolved,” says Ahna Skop, a UW-Madison professor of genetics and an expert on cell division. The idea is “logical and well thought out. I’ve already sent the paper to every cell biologist I know. It simply makes sense to be thinking about the cell and its contents in the context of where they may have come from.”

    The way cells work when they divide, she notes, requires the interplay of molecules that have evolved over many millions of years to cut cells in two in the process of cell division. The same molecular functions, she argues, could be repurposed in a way that conforms to the theory advanced by the Baums. “Why spend the energy to remake something that was made thousands of years ago to pinch in a cell? The functions of these proteins just evolve and change as the organism’s structure and function change.”

    Knowing more about how the eukaryotic cell came to be promises to aid biologists studying the fundamental properties of the cell, which, in turn, could one day fuel a better understanding of things like cancer, diabetes and other cell-based diseases; aging; and the development of valuable new traits for important crop plants.

    One catch for fleshing out the evolutionary history of the eukaryotic cell, however, is that unlike many other areas of biology, the fossil record is of little help. “When it comes to individual cells, the fossil record is rarely very helpful,” explains David Baum. “It is even hard to tell a eukaryotic cell from a prokaryotic cell. I did look for evidence of microfossils with protrusions, but, not surprisingly, there were no good candidates.”

    A potentially more fruitful avenue to explore, he suggests, would be to look for intermediate forms of cells with some, but not all, of the features of a full-blown eukaryote. “The implication is that intermediates that did exist went extinct, most likely because of competition with fully-developed eukaryotes.”

    However, with a more granular understanding of how complex cells evolved, it may be possible to identify living intermediates, says David Baum: “I do hold out hope that once we figure out how the eukaryotic tree is rooted, we might find a few eukaryotes that have intermediate traits.”

    “This is a whole new take (on the eukaryotic cell), which I find fascinating,” notes UW-Madison biochemistry Professor Judith Kimble. “I have no idea if it is right or wrong, but they’ve done a good job of pulling in detail and providing testable hypotheses. That, in itself, is incredibly useful.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
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