Brain

Scientists from RIKEN and the University of California San Diego, in collaboration with international partners have found a way to significantly reduce the amount of energy required by organic light emitting diodes (OLEDs). OLEDs have attracted attention as potential replacements for liquid crystal diodes, since they offer advantages such as being flexible, thin, and not requiring backlighting.

The group achieved the advance, published in Nature, by developing a new way to manipulate the "excitons"--pairs of electrons and holes--that are key to the transport of electrons within OLEDs. Essentially, current passing through the device creates such pairs, and when they change to a lower energy level, and emit visible light in the process. Normally, the excitons in OLEDs arise in two patterns, with the spins being either the same or opposite, and the ones with same spins--known technically as triplet excitons--are three times more common. However, the singlets, which are created along with the triplets, require more energy, and though they can be converted into triplets it still means that the device as a whole requires the energy to create them in the first place.

In the current work, the group found a way to lower the voltage so that only triplets are formed. The work began with fundamental research to understand the basic physics behind the creation of excitons using precise single-molecule electroluminescence measurements using a scanning tunneling microscope (STM) combined with an optical detection system. They prepared a model system based on an isolated molecule of 3, 4, 9, 10-perylenetetracarboxylicdianhydride (PTCDA), an organic semiconductor, adsorbed on a metal-supported ultrathin insulating film. They used a special technique to impart a negative charge to the molecule. Then, they used the current from an STM (scanning tunneling microscope) to induce luminescence in the molecule, and monitored what type of exciton was created based on the emission spectrum. The measurements showed that at low voltage, only triplets were formed. Theoretical calculations by Kuniyuki Miwa and Michael Galperin at UC San Diego confirmed the experimental results and substantiated the mechanism.

"We believe," says Kensuke Kimura of the RIKEN Cluster for Pioneering Research, "that we were able to do this thanks to a previously unknown mechanism, where electrons are selectively removed from the charged molecule depending on their spin state."

"It was very exciting to discover this new mechanism," says Yousoo Kim, leader of the Surface and Interface Science Laboratory in the RIKEN CPR, "We believe that these findings could become a general working principle for novel OLEDs with low operating voltage."

The consequences of aging are damage and degeneration of cells, which leads to loss of function, vulnerability to disease, and eventually, death. A hallmark of the aging process is the progressive decline of the nervous system, including both motor and cognitive functions. To complicate matters, natural variation in aging populations makes it difficult to study the factors that contribute to behavioral decline. Because the human aging process is typically slow, elucidating aging biomarkers and predicting individual differences has proven to be very challenging.

With the help of the common fruit fly (D. melanogaster), which ages quickly because it only lives about 60 days, neuroscientists from Florida Atlantic University's Charles E. Schmidt College of Science provide insights into healthy aging by investigating the effects of a foraging gene on age and stress tolerance.

When most organisms are deprived of oxygen, their brain cells lose homeostasis and are subjected to oxidative stress, or too many free radicals that cause cell damage or death. When fruit flies are deprived of oxygen, however, they slow down their metabolism and enter into a reversible coma, which enable them to survive harsh environmental conditions. Protein kinase G, or PKG, is an enzyme that regulates several biological processes such as muscular contraction and the dilation of blood vessels. This enzyme also regulates synaptic transmission and neuronal function.

It is known that the differences in the foraging (for) gene, which encodes for PKG, is responsible for differences in neuroprotection during severe oxidative stress. The for gene or one of its similar gene sequences is conserved across many species and has been implicated in several behavioral physical traits including feeding, sleep, learning and memory, and environmental stress tolerance. What is not known is how age affects behavior and stress tolerance.

In a study published in the Journal of Experimental Biology, FAU researchers are the first to report that PKG levels in fruit flies affect deterioration due to aging with a robust behavioral component. They have discovered that the for gene confers protection during low oxygen stress at the expense of longevity and a decline in locomotor activity with age in fruit flies. It's a trade-off - higher tolerance to low-oxygen stress increases fitness early in life, but comes at a cost to lifespan and locomotor activity later in life. These findings suggest a novel role for the PKG pathway in healthy aging and senescence.

Results of the study reveal that under severe anoxic stress (1 percent oxygen), flies expressing high levels of PKG drop into the coma faster, and this holds true in both young and old flies. The researchers also show that PKG influences stress tolerance in old flies under hypoxic conditions (3 percent oxygen) with flies expressing low levels of PKG, significantly increasing their activity during the stress.

Interestingly, the researchers found the same effect with age in normoxic (21 percent oxygen) conditions, indicating that age itself is a stress. The researchers also found that low PKG flies live longer.

"By understanding functional decline, we will be able to find biomarkers of aging and identify therapeutic interventions to counteract the deleterious effects of aging," said Ken Dawson-Scully, Ph.D., associate professor of biological sciences in FAU's Charles E. Schmidt College of Science and a member of the FAU Brain Institute (I-BRAIN). "With increasing human lifespan comes a need to understand how we also can age well."

Functional senescence, defined in this study as inherent age-related decline in physiological and behavioral function, may be affected by pleiotropic genes, which control more than one trait. Antagonistic pleiotropy occurs when one trait is beneficial to an organism's fitness and the other is detrimental. Because genetic conflicts may arise from a number of physiological, developmental or behavioral sources, pleiotropy is more commonly referred to as "trade-offs" between early- and late-life performance in animal models of aging such as worms, fruit flies and mice.

"Regardless of whether this study is indicative of behavior and fitness consequences in nature, our results make the fruit fly a clear choice for investigating potential diseases involving energy dysfunction," said Stephanie P. Kelly, Ph.D., co-author and a scholar of the FAU Brain Institute and a graduate student in integrative biology in FAU's Charles E. Schmidt College of Science.

DURHAM, N.C. -- Coal ash solids found in sediments collected from Sutton Lake in 2015 and 2018 suggest the eastern North Carolina lake has been contaminated by multiple coal ash spills, most of them apparently unmonitored and unreported until now.

"Our results clearly indicate the presence of coal ash at the bottom of Sutton Lake and suggest there have been multiple coal ash spills into the lake from adjacent coal ash storage facilities after, and even before, floodwaters from Hurricane Florence caused major flooding in 2018," said Avner Vengosh, professor of geochemistry and water quality at Duke University's Nicholas School of the Environment, who led the research.

"The levels of coal ash contaminants we detected in Sutton Lake's sediments, including metals with known environmental impacts, are similar to or higher than what was found in stream sediments contaminated by the 2008 Tennessee Valley Authority coal ash spill in Kingston, Tennessee, or the 2014 Dan River spill here in North Carolina," Vengosh said.

Sutton Lake served as an impoundment for a Duke Energy coal-fired power plant from the 1970s until the plant was retired and replaced with a natural gas-powered plant in 2013. It is located on the Cape Fear River about 11 miles upstream from the city of Wilmington, and is now widely used for recreational boating and fishing. In September 2018, floodwaters from Hurricane Florence inundated the lake and an adjacent coal ash landfill before flowing back into the Cape Fear.

Coal ash has long been known to contain high levels of toxic and carcinogenic elements that can pose ecological and human health risks if they leak into the environment. Power plants in the United States generate about 100 million tons of the ash a year. About half of it is stored in landfills or impoundments, in most cases adjacent to waterways.

"What's happened at Sutton Lake highlights the risk of large-scale unmonitored spills occurring at coal ash storage sites nationwide. This is particularly true in the Southeast where we see many major land-falling tropical storms and have a large number of coal ash impoundments located in areas vulnerable to flooding," Vengosh said.

While several lines of evidence suggest the coal ash solids found in Sutton Lake originate from multiple spills, further analysis will be needed to determine the timeline of these events and if similar unmonitored spills have also happened in other lakes near coal ash ponds in North Carolina, Vengosh said.

The spills could have been caused by floods, he noted, but other causes such as accidental release or past dumping practices cannot be ruled out

He and his colleagues published their peer-reviewed study May 24 in the journal Science of the Total Environment.

To do the study, they conducted four independent sets of laboratory tests on bottom sediments collected in October 2018 from seven sites in Sutton Lake and three sites in the adjacent Cape Fear River. They also analyzed three sediment samples collected from Sutton Lake in 2015 and three more collected that same year from nearby Lake Waccamaw, which has never served as a coal ash impoundment.

The researchers analyzed each sample using four different methods for detecting and measuring the possible presence of coal ash solids -- magnetic susceptibility, visual observation of microscopic coal ash particles, trace element distributions, and strontium isotope ratios.

The tests revealed high levels of coal ash solids mixed with natural sediments in the samples collected from Sutton Lake in both 2018 and 2015.

Among the contaminants detected were many metals -- including arsenic, selenium and thalium, once used as rat poison -- that have toxic impacts at elevated levels. The metals are naturally found in coal and are enriched in coal-ash residuals when the coal is burned.

Past studies by Vengosh's lab have shown that some of these metals, such as arsenic, can be released from coal ash solids into water trapped between grains of sediment at the lake's bottom, where they build up and, over time, bioaccumulate up the local food web. A 2017 study by Duke University Ph.D. student Jessica Brandt revealed that 85% of all fish tissue samples collected from Sutton Lake still contained selenium at levels that exceeded Environmental Protection Agency standards four years after the coal-fired power plant there was retired. Another study showed that strontium isotope ratios in the inner ears of fish from Sutton Lake now mirror the ratios found in coal ash.

"A coal ash spill is not a one-time contamination," Vengosh said. "It builds up a legacy in the environment. Even if you close the site, the legacy and threat remain, as our research has revealed at Sutton Lake and other coal ash spill sites such as Kingston, Tennessee. Collectively, these findings imply that the distribution and impact of coal ash in the environment is far larger than previously thought."

A study conducted by a team of researchers from the Cancer Science Institute of Singapore (CSI Singapore) at the National University of Singapore has revealed a close association between liposarcoma (LPS), a type of cancer that develops from fat cells, and the bromodomain and extraterminal (BET) protein family.

In the study recently published in prestigious scientific journal, Nature Communications, in March 2019, the researchers found that the development of LPS is highly dependent on the presence of BET proteins, and the ability to deplete BET proteins makes the protein family a promising cancer target for LPS.

Liposarcoma is currently treatable by surgery and radiation therapy. Chemotherapy using a recently approved chemotherapy agent, trabectedin, can also be prescribed to patients who are at high risk of recurrence or metastasis. The effectiveness of trabectedin, however, can be hampered by clinical toxicity, unresponsiveness and acquired resistance, and development of other forms of novel therapeutic interventions that can overcome these inefficacy.

The NUS researchers therefore focused its study on recurrent LPS. Through a detailed analysis of the genetic elements responsible for the development of LPS in samples of patients who have a recurrence of the cancer or are resistant to standard therapies, the researchers discovered that the main DNA conversion programme in LPS is fostered by BET proteins.

The researchers then investigated the inhibition of LPS development using BET protein degrading agent, ARV-825, and found that it was capable of disrupting the core transcriptional program in LPS and prevent the cancer development by depleting BET proteins. In addition, the researchers observed that LPS cells resistant to trabectedin were also susceptible to the depletion of BET proteins, thereby making BET protein a promising target not only for suppressing LPS development but also for overcoming acquired resistance to the chemotherapy agent.

Professor H. Phillip Koeffler, Senior Principal Investigator at CSI Singapore, led the study. He said, "The findings to our study have important clinical implications for LPS. It uncovers the essential roles and desirable therapeutic potentials of BET proteins in LPS, which paves the way for new therapeutic strategies to be designed against the ailment. The effectiveness of ARV-825 in suppressing LPS development described in our study also encourages further translation of BET protein degraders into effective anti-cancer drugs."

Moving forward, the researchers will look into ways to reduce LPS patients' resistance to drug treatments, and identify other targets that may be hindering their response to the treatments.

A recent, updated predictive analysis of the three WHO-defined molecular subgroups based on isocitrate dehydrogenase 1/2 (IDH) mutation status and 1p/19q co-deletion status represented in the high-risk treatment arms of the NRG Oncology clinical trial NRG-RTOG 9802 indicates that both IDH-mutant sub-groups (IDHmut-noncodel and IDHmut-codel) could benefit from the addition of PCV chemotherapy to radiotherapy treatment. This data was presented during a "Best of ASCO" oral presentation in the Central Nervous Systems Tumors Session at the American Society of Clinical Oncology (ASCO) Annual Meeting.

NRG-RTOG 9802 was a phase III Trial that assessed patients with high-risk low-grade gliomas (defined as patients at least 40 years old or who have had incomplete tumor removal) that were treated with radiotherapy (RT) with or without combination chemotherapy treatment including the drugs procarbazine, lomustine, and vincristine (PCV chemotherapy) after the patients received a biopsy or surgical resection. This analysis studied a subset of the specimens from which tissue was available for molecular profiling.

"This is the first phase III trial to evaluate the predictive value of WHO subgroups in low-grade gliomas using long-term overall survival data with the current standard of care. The results support the notions that there are benefits of PCV therapy to RT for both IDHmut-noncodel and IDHmut-codel subgroups; whereas, high-risk low-grade glioma patients with IDHwt tumors did not demonstrate any benefit from this treatment.," stated Erica H. Bell, PhD, Associate Professor of the Department of Radiation Oncology at The Ohio State University and the first author for this NRG-RTOG 9802 abstract.

One hundred and six specimens of the 251 eligible patients from the trial could be analyzed as they had sufficient tissue and quality DNA for profiling. Of these specimens, 41% were categorized as IDHmut-noncodel, 35% were IDHmut-codel, and 24% were IDHwt. No statistically significant differences between progression-free survival (PFS) and overall survival (OS) was observed with the addition of PCV chemotherapy in the IDHwt subgroup; however, both IDH-mutant subgroups were significantly correlated with longer PFS (IDHmut/non-co-deleted, p=0.003; IDHmut/co-deleted; p

"This study demonstrates the importance of incorporating the new WHO sub-groups into the clinical routine as it enhances the prognostic and now predictive clarification of patients with low-grade glioma, provides further insight into resistance to radiation and PCV, and guides clinical decision-making," stated Arnab Chakravarti, MD, the senior author of the secondary analysis and Chair of Radiation Oncology at The Ohio State University Comprehensive Cancer Center -Arthur G. James Cancer Hospital.

Thanks to a team of researchers from the University of Illinois at Urbana-Champaign and the University of Massachusetts Amherst, scientists are able to read patterns on long chains of molecules to understand and predict behavior of disordered strands of proteins and polymers. The results could, among other things, pave the way to develop new materials from synthetic polymers.

The lab of Charles Sing, assistant professor of chemical and biomolecular engineering at Illinois, provided the theory behind the discovery, which was then verified through experiments conducted in the lab of Sarah Perry, assistant professor of chemical engineering at UMass Amherst, and Illinois alumna. The collaborators detailed their findings in a paper titled "Designing Electrostatic Interactions via Polyelectrolyte Monomer Sequence" published in ACS (American Chemical Society) Central Science.

The colleagues set out to understand the physics behind the precise sequence of charged monomers along the chain and how it affects the polymer's ability to create self-assembling liquid materials called complex coacervates.

"The thing that I think is exciting about this work is that we're taking inspiration from a biological system," Sing said. "The typical picture of a protein shows that it folds into a very precise structure. This system, however, is based around intrinsically disordered proteins."

This paper builds on earlier findings from Perry and Sing from 2017, which ultimately aims to help advance smart material design.

"Our earlier paper showed that these sequences matter, this one shows why they matter," Sing explained. "The first showed that different sequences give different properties in complex coacervation. What we're able to now do is use a theory to actually predict why they behave this way."

Unlike structured proteins, which interact with very specific binding partners, most synthetic polymers do not.

"They are fuzzier in that they will react with a wide range of molecules in their surroundings," Sing explained.

They found that despite this fact, the precise sequence of the monomers along a protein (the amino acids) really does make a difference.

"It has been obvious to biophysicists that sequence makes a big difference if they are forming a very precise structure," Sing said. "As it turns out, it also makes a big difference if they are forming imprecise structures."

Even unstructured proteins have a precision associated with them. Monomers, the building blocks of complex molecules, are the links to the chain. What Sing's group theorized is that by knowing the sequence of polymers and monomers and the charge (positive, negative or neutral) associated with them, one can predict the physical properties of the complex molecules.

"While researchers have known that if they put different charges different places in one of these intrinsically disordered proteins, the actual thermodynamic properties change," Sing said.

"What we are able to show is that you can actually change the strength of this by changing it on the sequence very specifically. There are cases here that by changing the sequence by just a single monomer (a single link in that chain), it can drastically change how these things are able to form. We have also proven that we can predict the outcome."

Sing adds that this information is valuable to biophysicists, bioengineers and material scientists alike. This discovery will help engineers understand a broad class of proteins and tune proteins to modify their behavior. It gives them a new way to put information into molecules for building new materials and make a better guess as to how these properties behave.

Materials scientists can, for example, use this information to have a level of control over a material to cause it to assemble into very complicated structures or make membranes that precisely filter out contaminants in water. Their hope is that scientists, inspired by biopolymers, can take this ability to predict the physical behaviors simply by reading the sequence to ultimately design new smart materials this way.

"This in some sense is bringing biology and synthetic polymers closer together," Sing said. "For example, at the end of the day, there is not a major difference in the chemistry between proteins and nylon. Biology is using that information to instruct how life happens. If you can put in the identify of these various links specifically, that's valuable information for a number of other applications."

A new study indicates that racism is toxic to humans.

A team of USC and UCLA scientists found that racist experiences appear to increase inflammation in African American individuals, raising their risk of chronic illness, according to the study published in the journal Psychoneuroendocrinology on April 18.

"We know discrimination is linked to health outcomes, but no one was sure exactly how it harmed health," said April Thames, associate professor of psychology and psychiatry at USC Dornsife College of Letters, Arts and Sciences. "I looked at it as a chronic stressor. Our results showed that racial discrimination appears to trigger an inflammatory response among African Americans at the cellular level."

The survival of all living things depends on their ability to respond to infections, stresses and injuries. Such threats trigger an immune system response to fend off pathogens and repair damaged tissues. A select group of genes are key to this defense mechanism, and inflammation is a sign that those genes are working to counter the threat or repair the damage.

Inflammation serves to protect an organism from a health threat. But if someone feels under threat for long periods of time, their health may suffer significantly with chronic inflammation.

"If those genes remain active for an extended period of time, that can promote heart attacks, neurodegenerative diseases, and metastatic cancer," says co-author Steve Cole of the University of California, Los Angeles.

In previous studies, Cole had found that inflammatory responses are heightened among people in socially-marginalized, isolated groups. "We've seen this before in chronic loneliness, poverty, PTSD, and other types of adversity," he says. "But until now, nobody had looked at the effects of discrimination."

Inflammation's link to racism

For the study, Thames and her co-authors focused on a group of 71 subjects: two-thirds of them were African Americans; the others were white.

In addition, 38 of the participants were positive for HIV. Their participation gave scientists a chance to study the effects of racism independently from the effects of the disease.

The scientists extracted RNA from the participants' cells and measured molecules that trigger inflammation, as well as those involved in antiviral responses. The research team found higher levels of the inflammatory molecules in African American participants.

The results also indicate that racism may account for as much as 50 percent of the heightened inflammation among African Americans, including those who were positive for HIV.

Ruling out other stressors

The scientists made sure that all the participants had similar socioeconomic background to account for financial stressors, which eliminated poverty as a potential factor for chronic inflammation among the people in the study.

"Racial discrimination is a different type of chronic stressor than poverty," Thames says. "People navigate poverty on a day-to-day basis and are aware that it is happening. They might even be able to address financial stressors through job changes, changes in earnings and financial management. But with discrimination, you don't always realize that it's happening."

Individuals' decisions or lifestyles can reduce the ill effects of some stressors, but racial discrimination is a chronic stressor that people have no control over. "You can't change your skin color," she says.

Thames notes that this latest study has an obvious limitation: The sample size was small. But she says the results signal that scientists should repeat the study with a larger sample to fully determine the inflammatory effects of racism on people of color.

Chestnut Hill, Mass. (5/30/2019) - Researchers have paired a specialized diet and a tumor-fighting drug and found the non-toxic combination helps to destroy the two major cells found in an aggressive form of brain cancer, the team reports in the online edition of the Nature group journal Communications Biology.

The international team combined a calorie-restricted diet high in fat and low in carbohydrates with a tumor-inhibiting antibiotic and found the combination destroys cancer stem cells and mesenchymal cells, the two major cells found in glioblastoma, a fast-moving brain cancer that resists traditional treatment protocols.

The ketogenic diet and the antibiotic 6-diazo-5-oxo-L-norleucine - first characterized in 1956 and referred to as DON - offer a non-toxic therapeutic strategy that could be used to manage the deadly brain cancer, said Boston College Professor of Biology Thomas N. Seyfried, a lead author of the paper with Boston College Senior Research Scientist Purna Mukherjee.

The researchers, probing a treatment modeled on evidence that glioblastoma is primarily a mitochondrial metabolic disease driven by fermentation, discovered the combination was able to penetrate the blood-brain barrier that shields the brain from both injury and interventions, they wrote in the article, titled "Therapeutic benefit of combining calorie-restricted ketogenic diet and glutamine targeting in late-stage experimental glioblastoma."

"We were surprised that the restricted ketogenic diet facilitated delivery of DON through the blood-brain barrier," said Seyfried, a lipid biochemist and author of the book Cancer As A Metabolic Disease (Wiley, 2012). "It appears from this study and our previous study with another drug, that the restricted ketogenic diet can be considered a novel drug delivery system for the brain. There is no drug known that can do this."

The team from Boston College, Harvard Medical School, Berg LLC., Venezuela's Zulia University, and Hungary's University of Budapest, studied the diet-drug intervention in mice that serve as the closest models to glioblastoma in humans.

The carbohydrate glucose and the amino acid glutamine are the two major fermentable fuels in the body that can drive the growth of glioblastoma, as well as most cancers, Seyfried said. Yet relatively few studies have simultaneously targeted these fuels as candidates for therapeutic management of glioblastoma.

In a report last December, Seyfried and colleagues identified glutamine fermentation as the "missing link" in the metabolic theory of cancer first posited by Nobel laureate Otto Warburg in 1931. Contrary to the theory that cancer is determined by genomic instability in the nucleus of a cell, the metabolic theory of cancer holds that cancer's deadly path begins in the mitochondria, where cells generate energy.

In their new study, the researchers administered DON, a glutamine antagonist, in concert with a calorie-restricted, ketogenic diet to treat late-stage tumor growth in the brain. DON targets the biochemical "missing link" - the reaction glutaminolysis - while the ketogenic diet both reduces glucose and elevates non-fermentable and neuroprotective ketone bodies, Seyfried said.

"The diet-drug therapeutic strategy killed tumor cells while reversing disease symptoms, and improving overall mouse survival," said Seyfried. "The therapeutic strategy also reduces edema, hemorrhage, and inflammation. Moreover, the calorie-restricted ketogenic diet facilitated DON delivery to the brain and allowed a lower dosage to achieve therapeutic effect."

In addition to Seyfried and Mukherjee, co-authors of the study include Marek A. Domin, of the Boston College Department of Chemistry's Mass Spectrometry Center and former undergraduate researcher Zachary M. Augur; Michael A. Kiebish of Berg LLC, Rodney Bronson of Harvard Medical School; Gabriel Arismendi-Morillo, of Zulia University, Venezuela; and Christos Chinopoulos of the University of Budapest, Hungary.

Glioblastoma is an aggressive primary human brain tumor that has resisted effective medical treatments and interventions for decades. The current standard of care combination of surgery, chemotherapy and radiation treatment offers to a median life expectancy of 15 to 16 months, often with debilitating side effects.

"The findings support the importance of glucose and glutamine in driving glioblastoma growth and provide a therapeutic strategy for non-toxic metabolic management," said Seyfried, who has been searching for alternative cancer treatments throughout his career.

Seyfried said next steps to further explore the combination would be to determine if the diet-drug therapeutic synergy found for glioblastoma could also be seen for other malignant cancers, as glucose and glutamine are the key fuels that drive most if not all malignant cancers regardless of cell or tissue origin.

Work opens a path to precise calculations of the structure of other nuclei.

In a study that combines experimental work and theoretical calculations made possible by supercomputers, scientists have determined the nuclear geometry of two isotopes of boron. The result could help open a path to precise calculations of the structure of other nuclei that scientists could experimentally validate.

Researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, in collaboration with scientists in Germany and Poland, determined the difference in a quantity known as the nuclear charge radius between boron-10 and boron-11. The nuclear charge radius indicates the size of an atomic nucleus — which often has relatively indistinct edges.

“This is one of the most complicated atomic nuclei for which it is possible to arrive at these precise measurements experimentally and derive them theoretically.” — Argonne nuclear physicist Peter Mueller

Nuclear charge radii are difficult to compute with high precision for atoms much larger than boron because of the sheer number of neutrons and protons whose properties and interactions must be derived from quantum mechanics.

Nuclear theory builds from quantum chromodynamics (QCD), a set of physical rules that apply to quarks and gluons that compose the protons and neutrons within the nucleus. But trying to solve the nuclear dynamics using QCD alone would be an almost impossible task due to its complexity, and researchers have to rely on at least some simplifying assumptions.

Because boron is relatively light — with only five protons and a handful of neutrons — the team was able to successfully model the two boron isotopes on the Mira supercomputer and study them experimentally using laser spectroscopy. Mira is part of the Argonne Leadership Computing Facility (ALCF), a DOE Office of Science User Facility.

“This is one of the most complicated atomic nuclei for which it is possible to arrive at these precise measurements experimentally and derive them theoretically,” said Argonne nuclear physicist Peter Mueller, who helped lead the study.

Looking at how the nuclear configurations of boron-11 (11B) and boron-10 (10B) differed involved making determinations at extraordinarily small length scales: less than a femtometer — one-quadrillionth of a meter. In a counterintuitive finding, the researchers determined that the 11 nucleons in boron-11 actually occupy a smaller volume than the 10 nucleons in boron-10.

To look experimentally at the boron isotopes, scientists at the University of Darmstadt performed laser spectroscopy on samples of the isotopes, which fluoresce at different frequencies. While most of the difference in the fluorescence patterns is caused by the difference in the mass between the isotopes, there is a component in the measurement that reflects the size of the nucleus, explained Argonne physicist Robert Wiringa.

To separate these components, collaborators from the University of Warsaw and Adam Mickiewicz University in Poznan carried out state-of-the-art atomic theory calculations that precisely describe the complicated dance of the five electrons around the nucleus in the boron atom.

“Earlier electron scattering experiments couldn’t really say for sure which was bigger,” Wiringa said. “By using this laser spectroscopy technique, we’re able to see for certain how the extra neutron binds boron-11 more closely.”

The good agreement between experiment and theory for the dimensions of the nucleus allows researchers to determine other properties of an isotope, such as its beta decay rate, with higher confidence. “The ability to perform calculations and do experiments go hand-in-hand to validate and reinforce our findings,” Mueller said.

The next stage of the research will likely involve the study of boron-8, which is unstable and only has a half-life of about a second before it decays. Because there are fewer neutrons in the nucleus, it is much less tightly bound than its stable neighbors and is believed to have an extended charge radius, Mueller said. “There is a prediction, but only experiment will tell us how well it actually models this loosely bound system,” he explained.

WEST LAFAYETTE, Ind. -- In 2004, researchers discovered a super thin material that is at least a 100 times stronger than steel and the best known conductor of heat and electricity.

This means that the material, graphene, could bring faster electronics than is possible today with silicon.

But to truly be useful, graphene would need to carry an electric current that switches on and off, like what silicon does in the form of billions of transistors on a computer chip. This switching creates strings of 0s and 1s that a computer uses for processing information.

Purdue University researchers, in collaboration with the University of Michigan and the Huazhong University of Science and Technology, show how a laser technique could permanently stress graphene into having a structure that allows the flow of electric current.

This structure is a so-called "band gap." Electrons need to jump across this gap in order to become conduction electrons, which makes them capable of carrying electric current. But graphene doesn't naturally have a band gap.

Purdue researchers created and widened the band gap in graphene to a record 2.1 electronvolts. To function as a semiconductor such as silicon, the band gap would need to be at least the previous record of 0.5 electronvolts.

"This is the first time that an effort has achieved such high band gaps without affecting graphene itself, such as through chemical doping. We have purely strained the material," said Gary Cheng, professor of industrial engineering at Purdue, whose lab has investigated various ways to make graphene more useful for commercial applications.

The presence of a band gap allows semiconductor materials to switch between insulating or conducting an electric current, depending on whether their electrons are pushed across the band gap or not.

Surpassing 0.5 electronvolts unlocks even more potential for graphene in next-generation electronic devices, the researchers say. Their work appears in an issue of Advanced Materials.

"Researchers in the past opened the band gap by simply stretching graphene, but stretching alone doesn't widen the band gap very much. You need to permanently change the shape of graphene to keep the band gap open," Cheng said.

Cheng and his collaborators not only kept the band gap open in graphene, but also made it to where the gap width could be tuned from zero to 2.1 electronvolts, giving scientists and manufacturers the option to just use certain properties of graphene depending on what they want the material to do.

The researchers made the band gap structure permanent in graphene using a technique called laser shock imprinting, which Cheng developed in 2014 along with scientists at Harvard University, the Madrid Institute for Advanced Studies and the University of California, San Diego.

For this study, the researchers used a laser to create shockwave impulses that penetrated an underlying sheet of graphene. The laser shock strains graphene onto a trench-like mold - permanently shaping it. Adjusting the laser power adjusts the band gap.

While still far from putting graphene into semiconducting devices, the technique grants more flexibility in taking advantage of the material's optical, magnetic and thermal properties, Cheng said.

Do we see a pear or an apple? The occipital cortex in our brain will activate itself to recognise it. A piece of bread or a nice plate of pasta with sauce? Another region will come into play, called middle temporal gyrus. Different regions are implicated in recognition of different foods, raw in one case and processed in the other, because two components of the so-called "semantic memory", the one that we always use to recognise the world around us, are involved. More specifically, according to new research labelled SISSA and just published in the Scientific Reports journal, to identify "nature" foods, such as fresh fruit, the "sensory" component of semantic memory is required, in which sensory information, like the visual or tactile ones, allow us to identify an object. On the other hand, for processed or cooked foods are preferentially engaged cerebral areas associated to semantic memory that are involved in the recognition of functional features, with which we succeed in identifying an object through the function we associate to it: as if the recognition of food came through the process it had undergone, its nutritional vales or the habits in eating it. The results of this study have opened up new prospects of investigation on how our memory functions and on how our brain processes information related to food.

The importance of identifying food processing

"Food is essential for life. It is therefore of paramount importance that its key characteristics (is it poisonous? is it tasty? is it nutritious?) are readily recognised. To come to our aid, in this case, is our semantic memory, which is a large personal store of information on everything that we know, including the sensorial or abstract properties of the objects. Semantic memory allows us to give a name and a meaning to what we have encountered during our existence" explain Miriam Vignando and Raffaella Rumiati, respectively lead author and research director: "Speaking of food, one of the key characteristics to identify is certainly the level of processing it has undergone".

Natural and processed food, living and non-living

"We hypothesised that the recognition of raw food is based on the properties that involve our senses: sight, taste, touch. Instead, we proposed processed food recognition to be based on its functional properties: the process it has undergone, the nourishment it is able to provide, the moment in which we have to eat it, for example". This division reflects the model of sensorial-functional memory proposed several years ago, to explain how semantic memory works. According to this approach, there is a part of semantic memory, the sensory part, responsible for identifying "living things", and a functional part, responsible for identifying the "non-living things". We wanted to understand if this approach could also be applied to identifying food" say the two scientists.

An experiment carried out with recognition tests

"To answer our question, in the study we enrolled healthy participants, and patients affected by different neurodegenerative diseases characterised by extensive damage to the parts of the brain associated with semantic memory". All the individuals were administered recognition tests: they were presented with images of food, natural and processed, but also images of non-edible items, divided between living things (for example plants) and non-living things (for example utensils). To explore the relationship between the integrity of semantic memory for the categories of interest and the cerebral volume, a "morphometric" technique was used called voxel based morphometry (VBM). This technique allows to correlate the score at a test, in this case at semantic tests, with the volume of the brain, shedding light on the regions that correspond to low scores if atrophied.

Identification of the cerebral regions connected with food recognition

The results confirm that the same cerebral region is involved in recognition of natural foods and living things, the occipital lateral cortex, involved in sensory semantic memory. Another part of the brain, the middle temporal gyrus, involved in functional semantic memory, is involved in recognising both processed foods and non-living things. "Our hypothesis is therefore confirmed" say Vignando and Rumiati. "But there is more: this research has allowed us to identify various cerebral regions that are strongly related to food recognition, as if there was a network of regions responsible for the retrieval and integration of information regarding food, making it possible for us to correctly interact with it. To eat it or cook it, for example. Therefore, this process would be the result of the joint action of different parts of the brain, some aimed at recognising its sensory and functional properties, others at integrating and coordinating behaviour on the basis thereof".

The clinical implications of the study

This is particularly interesting if we think about possible connections with more clinical implications: indeed, one of the most frequent symptoms of several neurodegenerative diseases is eating disorders. This study paves the way for an investigation of the role that semantic memory plays in this behaviours.

Even a short stay for travelers in cities with high levels of air pollution leads to breathing problems that can take at least a week from which to recover, a new study shows.

Led by researchers at NYU School of Medicine, the study is the first of its kind, say the authors, to analyze pollution-related coughing and breathing difficulties, and recovery times upon returning home, in healthy, young adults traveling internationally.

Published earlier this month in the Journal of Travel Medicine, the finding is timely given that the number of tourists travelling internationally is expected to grow to 1.8 billion by 2030, according to the World Tourism Organization.

"We had several reports that tourists were feeling sick when visiting polluted cities, so it became important for us to understand what was really happening to their health," says senior study investigator Terry Gordon, PhD, a professor in the Department of Environmental Medicine at NYU Langone Health.

For the study, researchers analyzed six measurements of lung and heart health in 34 men and women traveling abroad for at least a week from the metropolitan New York City area. Most were visiting family in cities with consistently high levels of air pollution, including Ahmedabad and New Delhi, India; Rawalpindi, Pakistan; and Xian, China.

Some destinations studied ? Beijing, Shanghai, and Milan ? are heavily polluted during certain months but have relatively cleaner air at other times. Other, mostly European, destinations such as Geneva, London; San Sebastien, Spain; Copenhagen; Prague; Stockholm; Oslo; and Reykjavik had consistently lower levels of air pollution. The research team noted that New York City has relatively low levels of air pollution, in part because of strict regulations, its location on the coast, and weather patterns.

Specifically, the study found that being in a polluted city reduced measures of lung function by an average of 6 percent and by as much as 20 percent in some people. Participants also ranked their respiratory symptoms from one (mild) to five (requiring treatment), reporting a cumulative average symptom score of eight.

People who visited the highly polluted cities reported as many as five symptoms, while those who visited lower pollution cities had fewer or none. Two patients sought medical attention because of their symptoms. The pollution levels of the cities studied did not make a significant difference in the blood pressure of visitors, researchers say.

All study participants had a normal body mass index (between 21 and 29 for men, and between 18 and 26 for women), and none had preexisting health conditions. Before embarking on their travels, all were taught how to measure their lung function and heart rate daily using commercially available spirometers (to measure lung function), wrist blood pressure monitors, and heart rate sensors. Researchers then compared the health data against levels of air pollution collected from local government agencies.

The researchers used international standards to categorize highly polluted cities as those having more than 100 micrograms per cubic meter of particulate matter (PM), or air pollution dust. Moderate pollution is anything between 35 and 100 micrograms per cubic meter of PM, and low pollutions levels are anything less than that.

"What travelers should know is that the potential effects of air pollution on their health are real and that they should take any necessary precautions they can," says study lead investigator M.J. Ruzmyn Vilcassim, PhD, a postdoctoral fellow in the Department of Environmental Medicine.

Gordon suggests that those visiting highly polluted cities should consider wearing masks or consult a doctor prior to travel if they have preexisting respiratory or cardiac health difficulties, and to consider avoiding travel during certain months. For instance, farmers burn their fields during the winter months in New Delhi, India, raising levels of pollutants in the city.

Although participants gradually returned to normal health, study investigators say there needs to be more follow-up research to know if there were long-term effects, or if longer stays would influence the pollution impact. Next, researchers plan to study international travelers who are more susceptible to the effects of air pollution, such as the elderly and people with asthma or heart conditions.

WASHINGTON -- Many people, including educators, believe learning styles are set at birth and predict both academic and career success even though there is no scientific evidence to support this common myth, according to new research published by the American Psychological Association.

In two online experiments with 668 participants, more than 90 percent of them believed people learn better if they are taught in their predominant learning style, whether that is visual, auditory or tactile. But those who believed in learning styles split evenly into an "essentialist" group, with more strongly held beliefs, and a "non-essentialist" group, with more flexible beliefs about learning styles, said lead researcher Shaylene Nancekivell, PhD, a visiting scholar at the University of Michigan.

"We found that some people are more likely to believe that students inherit their learning style from their parents and that learning styles affect brain function," she said. "We also found that educators who work with younger children are more likely to hold this essentialist view. Many parents and educators may be wasting time and money on products, services and teaching methods that are geared toward learning styles."

In their responses to survey questions, the essentialist group members were more likely to state that learning styles are heritable, instantiated in the brain, don't change with age, mark distinct kinds of people, and predict both academic and career success. The non-essentialist group held looser beliefs about learning styles, viewing them as malleable, overlapping and more determined by environmental factors. The research was published online in the Journal of Educational Psychology.

Psychological essentialism is the belief that certain categories of people have a true nature that is biologically based and highly predictive of many factors in their lives. People with essentialist opinions about learning styles may be more resistant to changing their strongly held views even when they learn that numerous studies have debunked the concept of learning styles, Nancekivell said.

Previous research has shown that the learning styles model can undermine education in many ways. Educators spend time and money tailoring lessons to certain learning styles for different students even though all students would benefit from learning through various methods. Students study in ways that match their perceived learning style even though it won't help them succeed. Some teacher certification programs incorporate learning styles into their courses, which perpetuates the myth for the next generation of teachers. Academic support centers and a plethora of products also are focused on learning styles, despite the lack of scientific evidence supporting them.

The first experiment included participants from the general U.S. workforce, including educators. The second experiment was weighted so that at least half of the participants were educators to provide a better understanding of their views. The small percentage of participants who didn't believe in learning styles weren't included in the analysis because the study was examining differing beliefs about learning styles. Demographic factors such as race, gender, parental status and income level didn't affect people's views on learning styles in the study, but educators of young children were more likely to have essentialist beliefs.

"My biggest concern is that time is being spent teaching young children maladaptive strategies for learning," Nancekivell said. "It is important that children from a very young age are taught with the best practices so they will succeed."

Previous surveys in the United States and other industrialized countries across the world have shown that 80% to 95% of people believe in learning styles. It's difficult to say how that myth became so widespread, Nancekivell said.

"It seems likely that the appeal of the learning styles myth rests in its fit with the way people like to think about behavior," she said. "People prefer brain-based accounts of behavior, and they like to categorize people into types. Learning styles allow people to do both of those things."

Combining big data with artificial intelligence has allowed University of Copenhagen researchers to determine whether you wrote your assignment or whether a ghostwriter penned it for you - with nearly 90 percent accuracy.

Several studies have shown that cheating on assignments is widespread and becoming increasingly prevalent among high school students. At the University of Copenhagen's Department of Computer Science, efforts to detect cheating on assignments through writing analysis by way of artificial intelligence have been underway for a few years. Now, based on analyses of 130,000 written Danish assignments, scientists can, with nearly 90 percent accuracy, detect whether a student has written an assignment on their own or had it composed by a ghostwriter.

Danish high schools currently use the Lectio platform to check if a student has handed in plagiarized work that has passages copied directly from a previously submitted assignment. High schools have a harder time discovering if a student has enlisted someone else to write the assignment for them, something that happens to a more or less systematized degree via online services. The case of the SRP, a major written assignment in the final year of Danish high school, is particularly telling. Because the assignment counts for double, students have gone as far as tendering out their writing assignments on the Danish classified website, Den Blå Avis.

"The problem today is that if someone is hired to write an assignment, Lectio won't spot it. Our program identifies discrepancies in writing styles by comparing recently submitted writing against a student's previously submitted work. Among other variables, the program looks at: word length, sentence structure and how words are used. For instance, whether 'for example' is written as 'ex.' or 'e.g.'," explains PhD student Stephan Lorenzen of the Department of Computer Science. He, along with the rest of the DIKU-DABAI research group, recently presented their findings at a major European AI conference.

Prior to setting the trap, an ethical debate

The program, Ghostwriter, is built around machine learning and neural networks - branches of artificial intelligence that are particularly useful for recognizing patterns in images and texts. MaCom, the company that provides Lectio to Danish high schools, has made a dataset of 130,000 written assignments from 10,000 different high school students available to Ghostwriter project researchers at the Department of Computer Science. For now, it is still a research project.

Stephan Lorenzen doesn't think that it is unrealistic for the program to find its way into high schools in the not too distant future, as schools must constantly stay apace with technological developments to address 'authorship verification'.

"I think that it is realistic to expect that high schools will begin using it at some point. But before they do, there needs to be an ethical discussion of how the technology ought to be applied. Any result delivered by the program should never stand on its own, but serve to support and substantiate a suspicion of cheating," believes Lorenzen.

Police and fake news

Ghostwriter's technological foundation can be applied elsewhere in society. For example, the program could be used in police work to supplement forged document analysis, a task carried out by forensic document examiners and others.

"It would be fun to collaborate with the police, who currently deploy forensic document examiners to look for qualitative similarities and differences between the texts they are comparing. We can look at large amounts of data and find patterns. I imagine that this combination would benefit police work," says Lorenzen, who emphasizes that ethical discussions are needed here as well.

The artificial intelligence used by researchers at the Department of Computer Science to detect cheating on assignments has a wide range of applications. It has already been used to analyze Twitter tweets to determine whether they were composed by actual users or penned by paid imposters or robots.

FACTS:

The ghostwriter program uses what is known as a Siamese neural network to distinguish the writing styles of two texts. The network is trained on large amounts of data to learn from representations of writing styles, which are then compared.

When a student submits an assignment, the network compares it against their previous assignments. For each previous assignment, the network provides a percentage score for writing style similarity against the new assignment.

In the end, a weighted average of these scores is calculated using a calculation that also takes other factors, such as delivery time, into account. This final score is presented as a percentage and indicates the similarity between the new assignment and the student's writing style.

The research group behind the result is DIKU-DABAI (Danish Center for Big Data Analytics driven Innovation). The group is headed by Professor Stephen Alstrup.

Access the research article "Detecting Ghostwriters in High Schools" here.

The research is supported by Innovation Fund Denmark.

A new study led by Boston Medical Center's Grayken Center for Addiction shows that opioid-related overdose deaths involving another substance is now the norm, not the exception, in Massachusetts. The researchers analyzed opioid overdose death data from the Massachusetts Department of Public Health, which showed that 82 percent of those deaths involved an opioid and another substance, including stimulants. Of importance, the researchers also identified specific sociodemographic factors and social determinants of health associated more with polysubstance opioid-related overdose deaths.

Published in Drug and Alcohol Dependence, the findings indicate a pressing need to address the social barriers impacting patients with substance use disorder who are using multiple substances, such as homelessness, mental health issues, and addiction treatment for those who are incarcerated, in order to reduce polysubstance use and subsequent overdose deaths.

Polysubstance use, or using more than one substance at a time, has become increasingly common in individuals with opioid use disorder. While previous research has looked at opioid overdose deaths and social determinants of health broadly, there have not been studies looking at polysubstance versus non-polysubstance overdose deaths and the social factors associated with those deaths, which this study looked to uncover.

BMC collaborated with the Massachusetts Department of Public Health and analyzed opioid-related overdose deaths in the state from 2014 to 2015 using data from the Massachusetts Public Health Data Warehouse, which links data from various state agencies at the individual level. They examined postmortem toxicology data to identify the drugs present at the time of death and grouped into three categories - opioids only; opioids and other substances not including stimulants; and opioids with stimulants, with or without other substances.

During the two year period studied, there were 2,244 opioid-related overdose deaths in Massachusetts with toxicology results available. Seventeen percent of those deaths had only opioids present, 36 percent had opioids and stimulants (primarily cocaine), and 46 percent had opioids plus other substances, but not stimulants. The data also indicated that individuals over the age of 24, non-rural residents, those with co-morbid mental illness, non-Hispanic black residents, and those with recent homelessness were more likely to have opioids and stimulants, such as cocaine or methamphetamine, in their systems at their time of death than opioids alone.

"As a provider, these findings indicate a pressing need to address and treat not just opioid use disorder, but other substances that patients are misusing," said lead author Joshua Barocas, MD, who also is an infectious disease physician at BMC and assistant professor of medicine at BU School of Medicine. The challenge, he says, is that while there are FDA-approved medications to treat opioid use disorder, there are not effective medications to treat other substances, such as cocaine or amphetamines.

Additionally, the data clearly shows that untreated mental illness and social determinants of health are risk factors for overdose death. Specifically, those who are homeless or have mental illness are more likely to use opioids and stimulants, and more work is needed to identify ways to better engage these individuals in care. "To truly make a difference in reducing opioid overdose deaths, we must tackle issues such as homelessness and access to mental health services. This means not only investing in treatment but also implementing tailored programs that address the specific barriers to accessing care."