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About Egghead

Egghead is a blog about research by, with or related to UC Davis. Comments on posts are welcome, as are tips and suggestions for posts. General feedback may be sent to Andy Fell. This blog is created and maintained by UC Davis University Communications, and mostly edited by Andy Fell.

Guided ultrasound plus nanoparticle chemotherapy cures tumors in mice

By Holly Ober

Thermal ablation with magnetic resonance–guided focused ultrasound surgery (MRgFUS)  is a noninvasive technique for treating fibroids and cancer. New research from UC Davis shows that combining the technique with chemotherapy can allow complete destruction of tumors in mice.

MRgFUS combines an ultrasound beam that heats and destroys tissue with a magnetic resonance imaging to guide the beam and monitor the effects of treatment. The effectiveness of the treatment can be limited by the need to spare normal tissue or critical structures on the tumor margins, as well as the need to eliminate micrometastases.

In a new paper in The Journal of Clinical Investigation, Katherine W. Ferrara, distinguished professor of biomedical engineering at UC Davis, and colleagues report on a strategy that can destroy an entire tumor without thermal destruction of the tumor margin. Her group demonstrated a dramatic increase in the concentration of anti-cancer chemotherapy within several types of MRgFUS thermal ablation-treated tumors.

The tumor shown at top left is heated with ultrasound (top right) resulting in accumulation of drug (bottom images). UC Davis image.

Clockwise from top left: Tumor (blue arrows) heated with ultrasound (red dashed line); heat map of tumor during treatment; PET scan shows nanoparticles in surviving tumor margin; bright contrast agent shows area damaged by heat. UC Davis image.

“MRgFUS is already FDA approved for the treatment of uterine fibroids and palliation of bone metastases. We hope to expand the indication for MRgFUS by supplementing it with chemotherapy,” said first author Andrew Wong, a graduate student with the UC Davis Physician Scientist Training Program.

Ferrara’s previous research has shown that ultrasound-induced mild hyperthermia can enhance the accumulation of tiny nanoparticles carrying anti-cancer drugs, but the accumulation is dependent on the type of tumor. Her group hypothesized that combining thermal ablation and chemotherapy could improve efficacy across multiple types of tumors.

The team used a variety of techniques including combined positron emission tomography/computed tomography (PET-CT), magnetic resonance imaging, autoradiography, and fluorescence imaging to track nanoparticles loaded with the chemotherapy drug doxorubicin in a mouse model of breast cancer.

They found that as the ultrasound damaged the tumor and induced a local immune response, nanoparticles accumulated in the tumor and the local drug concentration increased 50-fold. The high drug concentrations continued over several weeks, increasing total exposure of the tumor to the drug.

Ferrara’s research team found that the enhanced drug accumulation induced by MRgFUS resulted in improved survival and a consistent cure in their preclinical model of breast cancer, even when part of the tumor was left intact.

They also demonstrated that an effective cure could be achieved with a carefully designed protocol involving heat-activated nanoparticles, which, when gently heated by ultrasound, release their chemotherapeutic payload in the vasculature surrounding the tumor.

Additional members of the team included Brett Z. Fite, Yu Liu, Josquin Foiret, Azadeh Kheirolomoom, Jai W. Seo, Katherine D. Watson, Lisa M. Mahakian, Sarah Tam and Alexander D. Borowsky. The work was supported by grants from the National Institutes of Health.

More information

Link to the paper (subscription may be required)

More about MRgFUS from UCLA Radiology

Holly Ober writes for the UC Davis Department of Biomedical Engineering. 

“Love hormone” oxytocin, possible anxiety drug, shows different effects in male and female mice

By Kathleen Holder

Clinical trials are testing whether oxytocin, sometimes called the “love hormone” for its role in intimacy and social bonding, has potential as a treatment for anxiety, depression and post-traumatic stress disorder. New research by behavioral neuroscientists Michael Steinman, Brian Trainor and colleagues at UC Davis suggests oxytocin may have different effects in men and women—and in certain circumstances the hormone may actually trigger anxiety.

In a series of experiments at the UC Davis Department of Psychology, the team administered doses of oxytocin with a nasal spray to male and female mice. Some of the mice were bullied by an aggressive mouse, an experience that reduces motivation to associate with unfamiliar mice. Consistent with previous studies, oxytocin increased the motivation for social interaction in stressed males.

Mouse

Male and female California mice show different responses to oxytocin, a possible treatment for anxiety and stress. (Mark Chappell/UC Riverside)

However, in stressed females, oxytocin had no effect. When non-stressed females received oxytocin, social motivation was reduced. This effect of oxytocin is similar to the effect of social stress.

“Reduced social motivation can be part of a depression-like syndrome,” said Trainor, an associate professor of psychology.

Trainor and colleagues found important differences in how stress affected the production of oxytocin. After stress, nerve cells in the brain produced more oxytocin in females but not in males. Steinman used a molecular marker to show that these oxytocin-producing cells were also more active in females that experienced stress. Steinman suggests, “This may help explain why oxytocin nasal spray makes females avoid social contact even though they did not experience social stress.”

Clinical studies have found that women with depression or PTSD have elevated oxytocin levels. Usually this result has been thought to reflect an increased drive for social support. The results of Trainor and colleagues suggest an alternate possibility.

“Our results show that stressed females have both reduced social motivation and increased oxytocin. It’s possible that oxytocin might contribute to a depression-like syndrome in females,” Trainor said. “If correct, inhibiting oxytocin action might have unanticipated benefits.”

The surrounding environment also influenced the effects of oxytocin. If mice were tested in a familiar home cage instead of a new environment, oxytocin reduced stress-related behaviors in males and females. This finding shows that the effects of oxytocin depend whether the environment is familiar or unfamiliar.

Trainor said his lab’s findings have implications for studies investigating the utility of oxytocin as a therapeutic.

“Most clinical studies investigating oxytocin as a treatment for depression or anxiety include only males,” he said. “It’s important to include both men and women in these studies. The effect of oxytocin may be different if administered by an unfamiliar person or by a person with whom the patient has a personal relationship.”

The UC Davis research project was supported by the National Institutes of Mental Health.

The results are to be published in Biological Psychiatry. An advance copy is available online.

In addition to Trainor and Steinman, a UC Davis Ph.D. alumnus who is now a post-doctoral researcher at New York University, co-authors were graduate student Natalia Duque-Wilckens; Gian Greenberg, a Ph.D. alum and a post-doctoral researcher at the Oregon Health and Sciences University; staff researcher Rebecca Hao; Katherine Campi, a Ph.D. alum who is now an assistant professor at Sierra College; Sarah Laredo, a Ph.D. alum who is now a post-doctoral researcher at Scripps Research Institute; graduate student Abigail Laman-Maharg; former undergraduates Claire Manning, Ian Doig, Kennan Walch and Eduardo Lopez, who all graduated in 2013; and psychology professor Karen Bales.

Additional information about this research is available at trainorlab.ucdavis.edu.

Kathleen Holder writes about Social Sciences for the College of Letters and Science at UC Davis. Follow her on Twitter: @kmholder.

 

Refael Klein flies the Aggie flag at the South Pole

If you think it’s been a bit chilly in the Sacramento region this week, spare a thought for UC Davis alumnus Refael Klein, lieutenant junior grade in the Commissioned Officer Corps of the National Oceanic and Atmospheric Administration. On a recent day temperatures climbed to 35 degrees below zero Fahrenheit at the South Pole, Klein’s home for the next year.

Aggie flag at South Pole

UC Davis alumn Refael Klein at the geographic South Pole, Nov. 2015. Klein will spend a year at the pole studying climate change.

“It’s been a big dream of mine to visit Antarctica,” said Klein in an interview before he left the U.S. “I feel very fortunate to have the opportunity.”

Klein graduated from UC Davis in 2010 with a degree in biological systems engineering and joined the NOAA Corps the following year. The Corps is the seventh uniformed service of the United States, tracing its history back to 1807 and the “Survey of the Coast” ordered by Thomas Jefferson. It operates research ships and aircraft and manages research projects around the world.

After Officer Candidate School, Klein served on research vessels in Hawaii and on the U.S. West Coast. He is currently assigned to NOAA’s global monitoring division, collecting information on the Earth’s atmosphere and changing climate from research stations around the world. In this capacity, he worked for a year in American Samoa and now a 13-month posting to the South Pole.

Klein will run the climatological laboratory at the South Pole base, running experiments and collecting data on behalf of other scientists. He will also act as lead scientist for the National Science Foundation, which operates the base, and liaison between all the various researchers there.

“I’m looking forward to getting involved in a science program that’s been running since the 1960s,” he said.

While the coastal regions of Antarctica are rugged with mountains and glaciers, the Pole itself is a high, icy desert, 10,000 feet up and flat in all directions. Over winter, the population of the base shrinks as complete darkness sets in.  Klein had to complete extensive physical and mental health exams and intensive training on leadership in confined environments before being cleared to go.

“It’s very akin to working on a ship,” Klein said. “You form a miniature society.”

The polar base does have internet access year round though, and Klein is blogging about his experiences for Voice of America’s Science World web site.

 

 

 

 

 

Innovation event jumpstarts dialogue on food, agriculture and health

By Kyeema Zerbe and Jennifer Hebets

The first ever event by the Innovation Institute for Food and Health (IIFH) struck surprising consensus in the food, agriculture and health agenda. The Challenge Definition Workshop held Oct. 29 set the stage for dialogue around such issues as crop selection, soil health, nutrition education, consumer decision-making, and technology feasibility – all under the overarching themes of health, sustainability, knowledge and governance. Next week, focus groups will deliberate the research questions behind such challenges, in preparation for the tour, hackathon and conference scheduled at the Solution Summit on December 2 and 3 in the UC Davis Conference Center.

Participants at the Oct. 29 IIFH Challenge Definition Workshop discussed food, hunger and innovation. Image ©Fred Greaves 2015

Participants at the Oct. 29 IIFH Challenge Definition Workshop discussed food, hunger and innovation. Image ©Fred Greaves 2015

The workshop saw the inaugural convening of many perspectives that will make up the innovation agenda. The charge for the Oct. 29 event was ambitious: define the most pressing issues facing food, agriculture and health. More than 100 participants from a unique cross-section of investors, entrepreneurs, students, researchers, and corporations represented the entire food system, from production to processing, and distribution to sale and education.

With an invigorating kick-off by  acting director Justin Siegel, and Mixing Bowl Hub cofounder Rob Trice, the event was powered by a shared vision for building uncommon collaborations and game-changing solutions to the challenges at hand. Through several rounds of active deliberation, more than 30 issues facing food, agriculture and health were narrowed down to a half dozen grand challenges. From there, a lively conversation resulted in consensus on four collective themes: health, sustainability, knowledge and governance.

The exercise proved that issues facing food, ag and health can each be defined from the perspective of those joining the conversation. The diverse participant mix revealed that such topics as undernutrition, GMOs, or technology, can be tackled from multiple angles. Therefore, it becomes necessary to establish common terms as a critical first step toward creative collaboration and consensus building.

In November, the next round of events will include Focus Group Retreats in which smaller groups of multifunctional teams will dive deeper into issues identified at the workshop. On December 2 and 3 the IIFH will host its first public Solution Summit in which hack teams, keynotes and panelists will explore innovative solutions with a broader audience.

The IIFH’s first event served as clear evidence of the much needed movement for promoting cross-sectoral collaboration to solve complex issues. The process of bringing together diverse perspectives, expertise and priorities is inevitably “messy”. However, as history has proven time and again, the greatest innovations often come from the least expected solutions.

Join the conversation by attending the next public event, the Solution Summit on December 2 and 3 – register here: http://foodaghealth.solutions/summit/

Kyeema Zerbe is Program Director for the Innovation Institute for Food and Health.

Often decried, polygyny may have some advantages

Is being a “sister wife” always a bad thing?

By Kathleen Holder

Much of the world frowns on the practice of polygamy. Most countries around the globe ban or restrict marriages to more than one spouse at a time. And polygyny—where one husband has more than one wife—is decried by the United Nations Human Rights Committee and women’s rights organizations as discriminatory to women.

But a new study of polygyny in Tanzania finds that the practice of sharing a husband may, in some circumstances, lead to greater health and wealth for women and their children.

UC Davis anthropologist Monique Borgerhoff Mulder and colleagues compared polygynous and monogamous households in 56 villages in northern Tanzania, where polygyny is widespread among certain ethnic groups, including the Maasai.

When comparing households within individual villages, polygynous households often had better access to food and healthier children. Polygynous households also owned more cattle and farmed more land than monogamous households. These findings support evolutionary anthropological accounts of marriage indicating that polygyny can be in a woman’s strategic interest when women depend on men for resources.

“If you have a choice of a guy who has 180 cows, lots of land and other wives, it might be better for you to marry him rather than a guy who has no wives, three cows and one acre,” Borgerhoff Mulder said.

Consistent with prior research, the study found that polygyny was associated with low food security and poor child health when looking at data across all villages. However, this pattern was accounted for by the tendency of polygyny to be most common in ecologically vulnerable and marginalized ethnic groups. This error of interpretation is known as the “ecological fallacy”, and flaws all previous analyses of large data sets like the Demographic and Health Surveys.

“Our study suggests that highly polygynous, predominantly Maasai, villages do poorly not because of polygyny, but because of vulnerability to drought, low service provision and broader socio-political disadvantages,” said David Lawson, a population health lecturer at the London School of Hygiene & Tropical Medicine and lead author of the study published in the Proceedings of the National Academy of Sciences.

Tanzania faces a high burden of food insecurity and malnutrition: 45 percent of children are of low height for their age, indicating chronic malnutrition with long term impacts on physical and cognitive development. Previous research by Lawson, Borgerhoff Mulder and colleagues showed that nearly 60 percent of Tanzanian Maasai children experience stunting.

The United Nations states that polygyny contravenes a woman’s right to equality with men and can have such serious emotional and financial consequences for her and her dependents that such marriages ought to be discouraged and prohibited.

However, the researchers highlight the importance of local context in studying the health implications of cultural practices, and suggest that in some settings, prohibiting polygyny could be disadvantageous to women by restricting their marriage options.

“The issue is not the number of partners,” Borgerhoff Mulder said. “Women should be assured the autonomy to make the decisions they want.”

The study is limited to food security and health, and cannot tell us about the wider potential for polygyny to cause harm, the researchers said. They also note that polygyny was only associated with superior outcomes when fathers and children were co-resident: outcomes for other polygynously-married women were indistinguishable from those of monogamous women. This suggests that any potential benefits of sharing a husband may be limited to the primary wife within a polygynous marriage.

The research was conducted in partnership with Savannas Forever Tanzania, which was co-founded by Borgerhoff Mulder, as well as the National Institute for Medical Research in Tanzania.

More information: Read the paper here

Kathleen Holder writes about social sciences for the UC Davis College of Letters & Science. Follow her on Twitter @kmholder.

UC Davis physicist praises 2015 Nobel prize for neutrinos

The sun, as seen in neutrinos captured by the Super-K experiment in Japan (R. Svoboda and K. Gordan).

The sun, as seen in neutrinos captured by the Super-K experiment in Japan (R. Svoboda and K. Gordan).

Robert Svoboda contributed to Nobel-winning neutrino experiments

By Becky Oskin

Billions of mysterious particles called neutrinos bombard your body every day. But catching even one neutrino is a huge effort. Nearly all neutrinos pass through people — and even our planet Earth — without a trace.

“There are 65 million neutrinos going through your thumbnail every second,” said Robert Svoboda, a UC Davis physics professor who has studied neutrinos for more than 25 years. “Only one will stop in your body during your lifetime.”

Svoboda collaborated on one of the two neutrino experiments honored this year by the 2015 Nobel Prize in Physics. The Nobel prizes went to Takaaki Kajita, leader of the Super-Kamiokande Collaboration in Japan, and Arthur McDonald, who leads the Sudbury Neutrino Observatory Collaboration in Canada.

Researchers want to understand neutrinos because the particles carry information about the inner workings of stars. The intense nuclear reactions inside stars, supernovas and nuclear reactors all produce neutrinos. Svoboda also thinks neutrinos may have played a role in creating more matter than antimatter just after the big bang. The big bang should have produced equal parts matter and antimatter, but our universe has mostly matter and seemingly very little antimatter, he said.

A weighty discovery

Svoboda joined the Super-Kamiokande experiment, or Super-K, in the early 1990s. Built in an old mine in Japan, the Super-K experiment centers on a 50,000-ton tank of purified water (about 13 million gallons). The tank’s sheer size means researchers can catch a few neutrinos randomly colliding with molecules in the water. Sensors monitor the faint light flashes created by these neutrino collisions. Super-K snags about 20 to 30 neutrinos on a typical day, Svoboda said.

Physicists at Super-K already knew neutrinos come in three types, also called flavors: electron, muon and tau. The names refer to the particles produced when a neutrino collides with matter. (UC Davis physicist Phil Yager, professor emeritus, helped capture the first direct evidence of the tau neutrino in the late 1990s.)

“Flavor is a name given to something we don’t quite understand,” Svoboda said. “We don’t know why there are three flavors. We’re probably missing something very important, and don’t know it yet.”

The Super-K group discovered that neutrinos oscillated, switching between different types. The Sudbury Neutrino Observatory confirmed that neutrinos switch flavors on their journey from the Sun. The oscillation observations confirmed that neutrinos have a very tiny mass. Before the experiment, most physicists thought neutrinos were massless particles. These results meant the Standard Model of the universe and its particles was wrong.

Next steps

New neutrino experiments may help solve some of these riddles. Svoboda is a leading scientist on the Deep Underground Neutrino Experiment (DUNE), a mega-neutrino detector at Fermilab in Batavia, Illinois. The DUNE experiment could lead to a better estimate of the mass of the Universe, and an improved measure of neutrino mass.

Whatever the results from DUNE, Svoboda expects more surprises from scientists studying neutrinos.

“This is the fourth Nobel prize for neutrino research, and it won’t be the last one,” Svoboda said.

Becky Oskin writes about science for the UC Davis College of Letters & Science. Follow her on Twitter @BeckyOskin.

Innovation Institute kicks-off “uncommon collaboration” for food and health with workshop

By Kyeema Zerbe

The Innovation Institute for Food and Health (IIFH) at UC Davis is kicking off a uniquely open collaboration on solving critical challenges in food, agriculture and health with an open workshop Oct. 29 inviting participants from all disciplines to provide input on the institute’s strategic focus.

Food and nutrition insecurity remain serious issues for more than 50 developing countries, according to the 2015 Global Hunger Index. And even as many as 10 percent of populations in developed countries go hungry, including in the fertile lands of California’s Central Valley. The UN Food and Agriculture Organization reports that almost 800 million people worldwide are chronically undernourished. With the global population expected to reach nearly 10 billion by 2050, society faces an uncertain future that demands a coordinated response from all sectors to improve access to adequate nutrition.

The IIFH was launched in January 2015 as a ground-breaking academic-corporate partnership between UC Davis and founding partner Mars, Incorporated, and seeks to establish a framework for accelerating innovative solutions to implementation.

As part of an inclusive strategy designed for maximum impact, the IIFH is gearing up to welcome stakeholders from across all sectors to help set the innovation agenda. A central tenet of the proposed approach involves partnering with researchers on a series of critical questions that, if addressed, would significantly improve human welfare locally or globally. Scale-up to application can involve any number of unique collaborations and additional corporate entities.

“Nutrition insecurity is widely prevalent in both developing and developed countries. We must look at where new systems need to be built and how current systems can be improved to provide safe, sustainable and secure nutrition for all,” said Justin Siegel, IIFH acting director and assistant professor of chemistry at UC Davis. “By enabling multi-sector partnerships and uncommon collaborations, the IIIFH can accelerate research discovery from inception to wide-scale delivery and community impact.”

At the first workshop on October 29, the IIFH invites questions from academic, industry, government, and community participants on the most important challenges for the entire food, agriculture and health ecosystem. This might include: what and how crops should be grown, how should they be processed, what products should they be transformed into, how to deliver those products equitably, how to educate consumers about nutritious products, or how to evaluate product impact on human health and welfare.

These questions will be refined in targeted consultations through November, when the IIFH will transition to eliciting potential solutions. Joining with the World Food Center, Apps for Ag and The Mixing Bowl Hub on December 2 and 3, the first open Solution Summit will engage participants in developing the best collaborative answers to pressing questions.

In the New Year, IIFH will launch an open call for proposals, with the goal of initiating projects on the three broad challenges of sustainable agriculture, food safety, and nutrition for all in spring 2016. To express interest in attending a future event, visit https://www.surveymonkey.com/r/SJXS7D9.

The “sixth sense:” How do we sense electric fields?

A variety of animals are able to sense and react to electric fields, and living human cells will move along an electric field, for example in wound healing. Now a team lead by Min Zhao at the UC Davis Institute for Regenerative Cures has found the first actual “sensor mechanism” that allows a living cell to detect an electric field. The work is published Oct. 9 in the journal Nature Communications.

“We believe there are several types of sensing mechanisms, and none of them are known. We now provide experimental evidence to suggest one which has not been even hypothesized before, a two-molecule sensing mechanism,” Zhao said.

Zhao and colleagues have been studying these “electric senses” in cells from both larger animals (fish skin cells, human cell lines) and in the soil-dwelling amoeba Dictyostelium. By knocking out some genes in Dictyostelium, they previously identified some of the genes and proteins that allow the amoeba to move in a certain direction when exposed to an electric field.

In the new work, carried out in a human cell line, they found that two elements, a protein called Kir4.2 (made by gene KCNJ15) and molecules within the cell called polyamines, were needed for signaling to occur. Kir4.2 is a potassium channel – it forms a pore through the cell membrane that allows potassium ions to enter the cell. Such ion channels are often involved in transmitting signals into cells. Polyamines are molecules within the cell that carry a positive charge.

Zhao and colleagues found that when the cells were in an electric field, the positively-charged polyamines tend to accumulate at the side of the cell near the negative electrode. The polyamines bind to the Kir4.2 potassium channel, and regulate its activity.

He cautioned that they do not yet have definitive evidence of how “switching” of the potassium channel by polyamines translates into directional movement by the cell.

Contributors to the paper are: Ken-ichi Nakajima, Kan Zhu, Yao-Hui Sun, Yoshihiro Izumiya, Bence Hegyi, Qunli Zeng, Christopher Murphy, J. Victor Small, Ye Chen-Izu, and Josef Penninger, with affiliations at the UC Davis Departments of Dermatology, Ophthalmology, Pharmacology, Biochemistry and Molecular Medicine, and the UC Davis School of Veterinary Medicine; Zhejiang University, Hanzhou, China; and the Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria.

The work was supported by grants from the National Institutes of Health, NSF, American Cancer Society, American Heart Association, Research to Prevent Blindness Inc., and the University of California.

Shale oil fracking, conventional crude drilling produce similar greenhouse gas emissions

By Kat Kerlin

It requires roughly the same level of greenhouse gas emissions to extract shale oil as it does to extract conventional crude oil, according to a pair of studies by UC Davis and Stanford University released this week by the U.S. Department of Energy’s Argonne National Laboratory.

The research analyzed the Eagle Ford shale play in Texas and the Bakken play in North Dakota. These plays are shale formations with low permeability that must be hydraulically fractured to produce oil and gas.

The Eagle Ford Shale in Texas is one of the largest oil and gas producing regions in the country.

The Eagle Ford Shale in Texas is one of the largest oil and gas producing regions in the country.

Eagle Ford and Bakken are the second and third largest oil-producing regions in the U.S., respectively, since 2012.  Together, Bakken and Eagle Ford accounted for 54 percent of oil production and 19 percent of gas production within seven major production regions in 2014.

Until now, there has been little information about how the production method impacts greenhouse gas levels.

Both studies showed that greenhouse gas emissions associated with shale oil production are similar to levels generated at conventional crude oil reserves, even after considering the flaring and venting of natural gas during the shale oil process. The emission intensity stays consistent during the lifespan of extraction at the oil play.

This contradicts an earlier estimate that the Bakken play might produce greenhouse gas emissions 20 percent higher than for crude oil production.

The Eagle Ford study was led by Sonia Yeh, a research scientist with the Institute of Transportation Studies at UC Davis. It looked at crude oil from different production zones for 2009–2013. Some zones produced more oil while others produced more gas. The study showed that wells in the gas-rich zone used roughly twice the amount of energy as wells in the oil-rich zone, which used an average of 1.2 percent of energy for production, extraction, and processing. Water use was also generally higher at the gas-rich wells.

“It was challenging to calculate the net energy use and net greenhouse gas emissions for Eagle Ford because of the wide range of products produced at these places, and there were no publicly available tools for horizontal drilling and hydraulic fracturing,” said Yeh. “The collaboration provided greater transparency and understanding of energy and climate impacts of oil production in these important regions.”

Sonia Yeh researchers greenhouse emissions at the UC Davis Institute of Transportation Studies.

Sonia Yeh researchers greenhouse emissions at the UC Davis Institute of Transportation Studies.

The studies calculate energy consumption and greenhouse gas emissions associated with the crude oil and natural gas extraction using the Oil Production Greenhouse Gas Emissions Estimator (OPGEE) model, with production data collected for shale oil well operations in both plays. This model estimates energy for the lifecycle—from the initial exploration to the refinery entrance gate—and includes production, processing and transport.

The research team incorporated the OPGEE results into the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model developed at Argonne National Laboratory to determine the full life-cycle energy and emissions impacts.

The research was funded by the Vehicle Technology Office and the Bioenergy Technology Office of the Energy Efficiency and Renewable Energy Office of the U.S. Department of Energy.

The full reports can be found online at greet.es.anl.gov.

Follow Kat on Twitter at @UCDavis_Kerlin.

Magnetic skyrmions at room temperature: New digital memory?

An exotic, swirling object with the sci-fi name of a “magnetic skyrmion” could be the future of nanoelectronics and memory storage. Physicists at UC Davis and the National Institute of Standards and Technology (NIST) have now succeeded in making magnetic skyrmions, formerly found at temperatures close to absolute zero, at room temperature.

“This is a potentially new way to store information, and the energy costs are expected to be extremely low,” said Kai Liu, professor of physics at UC Davis and corresponding author of a paper on the work, published in the journal Nature Communications Oct. 8.

Skyrmions were originally described over 50 years ago as a type of hypothetical particle in nuclear physics. Actual magnetic skyrmions were discovered only in 2009, as chiral patterns of magnetic moments — think of a moment as a tiny compass needle — in materials close to absolute zero temperature, in the presence of a strong magnetic field.

Nanodots induce magnetic skyrmions (arrows) in the film below. Skyrmions are stable magnetic structures and could be a new way to store data at low energy cost. (Kai Liu/UC Davis)

Nanodots induce magnetic skyrmions (arrows) in the film below. Skyrmions are stable magnetic structures and could be a new way to store data at low energy cost. (Dustin Gilbert and Kai Liu/UC Davis)

Magnetic skyrmions fall into two types, Liu said: “Bloch skyrmions,” with a hurricane-like spiral pattern of magnetic moments around a perpendicular center, surrounded by magnetic moments oriented in the opposite direction to the center; and “hedgehogs,” where the magnetic moments orient like spikes on a  hedgehog or sea urchin.

The interesting thing about magnetic skyrmions, Liu said, is that they are “topologically protected:” they can be continuously deformed, in the same way that a coffee mug shape can be deformed into a bagel shape, but they do not readily go back into a state where all the magnetic moments are aligned. That means they can potentially store information at an energy cost much lower than current technology, Liu said.

Together with graduate student Dustin Gilbert, now a postdoctoral fellow at NIST, Liu and colleagues designed a nanosynthesis approach to achieve artificial “Bloch” magnetic skyrmions at room temperature. They created a pattern of magnetic nanodots, each about half a micron across, on a multilayered film where the magnetic moments are aligned normal to the plane. They used ion beam irradiation to modify the interface between the dots and the film to allow “imprinting” of the magnetic moments of the dots into the film.

Using neutron-scattering at NIST Center for Neutron Research, they were able to resolve the magnetic profiles along the depth of the hybrid structure. Combined with magnetic imaging studies at NIST and Lawrence Berkeley Laboratory, they were able to find the first direct evidence of arrays of stable spiral magnetic skyrmions beneath the nanodots at room temperature, even without an external magnetic field.

The availability of stable magnetic skyrmions at room temperature opens up new studies on their properties and potential development in electronic devices, such as nonvolatile magnetic memory storage.

Coauthors on the paper are Brian Maranville, Andrew Balk, Brian Kirby, Daniel Pierce, John Unguris and Julie Borchers at NIST, and Peter Fischer, LBL and UC Santa Cruz. Nanofabrication work and other characterizations were carried out in Liu’s laboratory and at the Center for Nano and Micro Manufacturing at UC Davis. The work was funded by the National Science Foundation.

More information

NIST, UC Davis scientists float new approach to creating computer memory (NIST)