Brain

A research team in Ehime University characterized the complex composition of chlorinated, brominated and mixed halogenated dioxins as well as their major precursors in soils from e-waste burning and dismantling areas in Agbogbloshie (Accra, Ghana), a major hub of informal e-waste processing in Africa. The findings were published on February 22, 2019 in Environmental Science & Technology.

E-waste, or Waste Electrical and Electronic Equipment (WEEE), refers to end-of-life products such as communication devices, consumer electronics and home appliances. E-waste contains substantial amounts of valuable metals to recycle, but is also considered as hazardous waste due to the presence of toxic substances such as heavy metals and many various plastic additives. A large volume of these hazardous waste materials has been recycled inappropriately, and treated informally in Asian and African developing countries using primitive methods such as circuit board heating and open burning of wires. These informal recycling activities have led to serious environmental pollution caused by the emission of not only contaminants contained in e-waste but also unintentionally formed secondary toxic chemicals.

Dioxin-like compounds, or simply dioxins, are a group of unintentional contaminants generated during informal processing of e-waste with a wide range of potential toxic effects. However, assessment of the environmental and health impacts of dioxins from e-waste is challenging due to their complex composition. Chlorinated dioxins including polychlorinated dibenzo-p-dioxins and dibenzofurans are combustion by-products of polyvinyl chloride (PVC) used in wire coating. Lesser-known brominated dioxins are thermal degradation products of brominated flame retardants (BFRs), which are plastic additives designed to prevent accidental fires. Mixed brominated/chlorinated dioxins are also generated during e-waste burning, but have not been well characterized because of the difficulties in analyzing their large number.

The research team in Ehime University used special analytical methods based on two-dimensional gas chromatography (GC×GC) and time-of-flight mass spectrometry (ToFMS) to conduct a comprehensive profiling of halogenated contaminants in the soils collected near e-waste burning and dismantling areas. Polybrominated and mixed halogenated dibenzofurans (PBDFs and PXDFs) were the major dioxins detected. Their composition profiles suggest that PBDFs were generated from polybrominated diphenyl ethers (PBDEs), a group of flame retardants commonly found in e-waste plastics; and PXDFs mainly from PBDFs through successive bromine-to-clorine exchange. High concentrations of PXDFs in e-waste burning areas indicate that these "hidden" dioxins may contribute substantially to the total toxicity of the e-waste-derived dioxin mixture, and need to be included in future environmental and human exposure risk assessment.

Targets to eliminate pain after surgery have driven increases in the use of opioids, and are a major cause of the opioid crisis in the USA, Canada and other countries. For the first time, a new Series of three papers, published in The Lancet, brings together global evidence detailing the role of surgery in the opioids crisis.

Chronic post-surgical pain is a growing problem as the population ages and more surgeries are done. It can occur after any type of surgery. Each year there are 320 million people having surgery, and chronic pain occurs in 10% of cases.

It typically begins as acute postoperative pain that is difficult to control, and develops into a persistent pain condition with features that are unresponsive to opioids. In response to this pain, clinicians often prescribe higher levels of opioids, but this can lead to tolerance and opioid-induced hyperalgesia (a counterintuitive increase in pain in line with increased opioid consumption), creating a cycle of increased pain and increased opioid use where pain remains poorly managed.

"Providing opioids for surgical patients presents a particularly challenging problem requiring clinicians to balance managing acute pain, and minimising the risks of persistent opioid use after surgery," says Series lead Professor Paul Myles, Monash University, Australia. "Over the past decade there has been an increasing reliance on strong opioids to treat acute and chronic pain, which has been associated with a rising epidemic of prescription opioid misuse, abuse, and overdose-related deaths. To reduce the increased risk of opioid misuse for surgery patients, we call for a comprehensive approach to reduce opioid prescriptions, increase use of alternative medications, reduce leftover opioids in the home, and educate patients and clinicians about the risks and benefits of opioids." [1]

Risks associated with prescription opioids

The opioid crisis began in the US during the mid-1990s and early 2000s, when inadequate pain relief was seen as a marker of poor quality healthcare. Opioids are now one of the most commonly prescribed medications in the USA with similar, although less marked, trends in other high-income countries, including the UK. Comparatively, many low-income countries worldwide have little access to opioids and cannot provide appropriate pain relief - as highlighted in The Lancet Commission on Global Access to Palliative Care and Pain Relief [2].

"From the mid-1990s, clinical guidelines and policies were created that aimed to eliminate pain, and clinicians were encouraged to increase opioid prescriptions. As a result, the use of prescription opioids more than doubled between 2001-2013 worldwide - from 3 billion to 7.3 billion daily doses per year, and has been linked to increases in misuse and abuse in some countries - like the US, Canada, Australia and the UK." Says Series author Dr Brian Bateman, Brigham and Women's Hospital, USA. [1]

Currently, opioids are often the best pain relief available for managing acute pain. In surgery, opioid administration reduces the dose of general anaesthetic needed, and timely and appropriate opioids after surgery improve patient comfort. However, the persistent use of opioids after surgery can predispose patients to long-term opioid use and misuse so ongoing must be carefully considered. In the USA, opioid prescribing for minor surgery has increased (up to 75% of patients are prescribed opioids at hospital discharge), and the risk of misuse increases by 44% for every week and for repeat prescription after discharge.

A US study of more than 155,000 patients having one of four low-risk surgeries (carpal tunnel repair, knee arthroscopy, keyhole surgery for gallbladder removal, or keyhole surgery for inguinal hernia repair) found that opioid prescriptions for each increased from 2004-2012, and that the average daily dose of opioid prescribed for post-surgical pain also increased by 13% (30 milligrams of morphine equivalent [MME]) across all procedures on average, with increases ranging from 8% (17 MMEs) for patients undergoing inguinal hernia repair to 18% (45 MMEs) for patients undergoing knee arthroscopy (see Figure in paper 2).

There are also marked international differences in opioid prescribing after surgery. Data comparing one US and one Dutch hospital found that 77% of patients undergoing hip fracture repair in the US hospital received opioids, whereas none did in the Netherlands hospital, and 82% of US patients received opioids after ankle fracture repair compared with 6% of Dutch patients. Despite these differences, patients in each of these countries show similar levels of satisfaction with pain management.

In addition, excessive amounts of opioids are prescribed to US patients after surgery. Studies between 2011-2017 found that 67-92% of US surgery patients reported not using all of their opioid tablets, typically leaving 42-71% of their prescribed pills unused.

As well as often being ineffective at treating chronic pain, opioid prescriptions for pain after surgery have been linked to prescription opioid misuse and diversion, the development of opioid use disorder, and opioid overdose. Storing excess opioid pills in the home is an important source of diversion, and in one study 61% of surgery patients had surplus medication with 91% keeping leftover pills at home.

Reducing opioid risks and improving management of chronic post-surgical pain

The authors call for a comprehensive approach to reduce these risks, including specialist transitional pain clinics, opioid disposal options for patients (such as secure medication disposal boxes and drug take-back events) to help reduce home-stored opioids and the risk of diversion, and options for non-opioid and opioid-sparing pain relief. More research is also needed to help effectively manage opioid tolerance and opioid-induced hyperalgesia.

"Ultimately, chronic pain after surgery requires a comprehensive biopsychosocial approach to treatment. Transitional pain clinics are a new approach at bridging the divide, aiming to eliminate overprescribing of opioids after surgery. These clinics could help identify those at risk of chronic pain after surgery, and offer additional clinic visits, review treatment, refer the patient to alternative services, such as rehabilitation, addiction medicine, mental health services, and chronic pain services. Together this could help to reduce opioid use and abuse." says Professor Myles. [1]

Clinical guidelines and policies must also provide consensus for prescribing opioids after surgery, offering clinicians default and maximum prescription levels. For example, there is currently no guide on how long surgical patients should remain on opioids. To counter this, in the USA, a study devised prescribing recommendations for various surgeries (based on patient surveys and prescription refills data) - recommending postoperative opioids for 4-9 days for general surgery procedures, 4-13 days for women's health procedures, and 6-15 days for musculoskeletal procedures. In addition, a study that adapted the default number of opioid pills prescribed from 30 to 12 showed marked decreases in the number of pills given after 10 common surgical procedures.

"Better understanding of the effects of opioids at neurobiological, clinical, and societal levels is required to improve future patient care," says Series author Professor Lesley Colvin, University of Dundee, UK. "There are research gaps that must be addressed to improve the current opioid situation. Firstly, we must better understand opioid tolerance and opioid-induced hyperalgesia to develop pain relief treatments that work in these conditions. We also need large population-based studies to help better understand the link between opioid use during surgery and chronic pain, and we need to understand what predisposes some people to opioid misuse so that we can provide alternative pain relief during surgery for these patients. These recommendations affect many areas of the opioid crisis and could benefit to the wider crisis too." [1]

Chinese scientists have synthesized new nanowires with high carrier mobility and fast infrared light (IR) response, which could help in high-speed communication. Their findings were published in Nature Communications on April 10th.

Nowadays, effective optical communications use 1550 nm IR, which is received and converted into an electrical signal for computer processing. Fast light-to-electrical conversion is thus essential for high-speed communications.

According to quantum theory, 1550 nm IR has energy of ~ 0.8 eV, and can only be detected by semiconductors with bandgaps lower than 0.8 eV, such as germanium (0.66 eV) and III-V compound materials such as InxGa1-xAs (0.35-1.42 eV) and InxGa1-xSb (0.17-0.73 eV). However, those materials usually have huge crystal defects, which cause substantial degradation of photoresponse performance.

Scientists from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences, City University of Hong Kong (CityU) and their collaborators synthesized highly crystalline ternary In0.28Ga0.72Sb nanowires to demonstrate high carrier mobility and fast IR response.

In this study, the In0.28Ga0.72Sb nanowires (bandgap 0.69 eV) showed a high responsivity of 6000 A/W to IR with high response and decay times of 0.038ms and 0.053ms, respectively, which are some of the best times so far. The fast IR response speed can be attributed to the minimized crystal defects, as also illustrated by a high hole mobility of up to 200 cm2/Vs, according to Prof. Johnny C. Ho from CityU.

The minimized crystal defect is achieved by a "catalyst epitaxy technology" first established by Ho's group. Briefly, the III-V compound nanowires are catalytically grown by a metal catalyst such as gold, nickel, etc.

"These catalyst nanoparticles play a key role in nanowire growth as the nanowires are synthesized layer by layer with the atoms well aligned with those in the catalyst," said HAN Ning, a professor at IPE and senior author of the paper.

New Haven, Conn. - Cthulhu is calling from the ancient depths -- and this time, researchers are only too happy to speak its name.

Researchers at Yale, Oxford, the University of Leicester, Imperial College London, and University College London have identified a 430 million-year-old fossil as a new species related to living sea cucumbers. They named the creature Sollasina cthulhu, after H.P. Lovecraft's tentacled monster, Cthulhu.

A study announcing the discovery appears April 10 in the journal Proceedings of the Royal Society B.

The new cthulhu, Sollasina, had 45 tentacle-like tube feet, which it used to crawl along the ocean floor and capture food. The creature was small, about the size of a large spider. It was found in the Herefordshire Lagerstätte in the United Kingdom, a site that has proven to be a trove of fossilized ancient sea animals.

"In this paper, we report a new echinoderm -- the group that includes sea urchins, sea cucumbers, and sea stars -- with soft-tissue preservation," said Yale paleontologist Derek Briggs, a co-author of the study. "This new species belongs to an extinct group called the ophiocistioids. With the aid of high-resolution physical-optical tomography, we describe the species in 3D, revealing internal elements of the water vascular system that were previously unknown in this group and, indeed, in nearly all fossil echinoderms."

The 3D reconstruction process involves grinding a fossil away, layer by layer, and taking photographs at each stage. This results in hundreds of slice images, which are digitally reconstructed into a "virtual fossil."

That's how the researchers were able to discern Sollasina's internal water vascular system and determine it is more closely related to sea cucumbers rather than to sea urchins.

"The water vascular system operates the tentacle-like structures that they used for locomotion and food capture," Briggs said. "The tube feet of living echinoderms are naked, but in the ophiocistioids they were plated. Our analysis strongly suggests that ophiocistioids diverged from the line leading to modern sea cucumbers."

The researchers said Sollasina's existence demonstrates that the sea cucumber skeleton was modified gradually during the assembly of its body plan.

Defensive compounds produced by microbes are a major source of antibiotics and other important medicines. But with resistant bugs appearing faster than potential allies, researchers are taking their search for drug candidates offshore.

Published in Frontiers in Microbiology, a new study reveals for the first time that a common species of seaweed, Laminaria ochroleuca, is a rich source of bacteria with antimicrobial and anticancer activities - and potential new drug candidates.

20,000 leads under the sea

Almost a century since Fleming discovered penicillin in a stray mold, scientists continue to look to microbes for new antibiotics and other medicines. To date, none has given more generously than the Actinobacteria: a family of soil- and seabed- dwelling bacteria who think they're fungi.

"About half of the 20,000+ microbe-derived drug candidates currently known come from Actinobacteria," says senior study author Dr. Maria de Fátima Carvalho of the Interdisciplinary Center of Marine and Environmental Research (CIIMAR), Portugal. "Now the supply of new species on land - where they form spores and branched networks just like a fungus - is beginning to run out."

But relatively underexplored marine Actinobacteria may yet prove an even richer source of bioactive microbial molecules.

"Several novel drug leads derived from marine Actinobacteria are already known," says Carvalho. "These include anticancer agent salinosporamide A, currently in clinical trials, and several new antibiotics that are effective against drug-resistant infections like MRSA and tuberculosis."

Kelp is at hand

Predominantly found in sediments on the sea floor, Actinobacteria can also live inside other organisms that live and feed there - including brown algae (seaweed).

"The brown alga Laminaria ochroleuca forms complex structures called kelp forests, which are among the most diverse and productive ecosystems in the world," says Carvalho. "But until now, no-one had characterized the Actinobacteria that live inside L. ochroleuca."

In other kelp species, Actinobacteria are known to provide protective compounds in exchange for nutrients and shelter, which could be a source of new drug candidates.

Carvalho's team analyzed a sample of L. ochroleuca from a rocky shore off northern Portugal.

"After six weeks of culture in the lab, we isolated 90 Actinobacterial strains from the sample."

Extracts from these Actinobacteria were then screened for antimicrobial and anticancer activity.

"Forty-five of the Actinobacterial extracts inhibited growth of Candida albicans, Staphylococcus aureus, or both."

Some extracts were active against these common pathogens even at extremely low concentrations, making them promising candidates for the discovery of antimicrobial drugs. Several also showed selective anticancer activity.

"Seven of the extracts inhibited growth of breast and particularly nerve cell cancers, while having no effect on non-cancer cells."

New drug candidates

"This study reveals that the seaweed L. ochroleuca is a rich source of Actinobacteria with promising antimicrobial and anticancer activities," sums up Carvalho.

Further tests on the most potent of these strains revealed that some of the effects are likely the result of newly discovered compounds.

"We identified extracts from two Actinobacteria strains that do not match any known compounds in the most comprehensive international database of natural bioactive compounds. We intend to follow up on these exciting results."

For the vast majority of cancer drugs experiencing shortages over a seven-year period, a new USC research study found no statistically significant effect of shortages on chemotherapy treatment.

"These findings are surprising in light of the substantial media and policy attention that the cancer drug shortage problem has garnered," said Mireille Jacobson, study coauthor and associate professor of gerontology at the USC Leonard Davis School and the Schaeffer Center for Health Policy & Economics.

Although the proportion of patients receiving treatment declined for six drugs, including fluorouracil, doxorubicin, and cytarabine, the use of 32 other cancer drugs was unaffected or even increased during shortage episodes. Likewise, dosages declined for only a few drugs during shortages. The results were published April 8 in Clinical Pharmacology & Therapeutics.

Researchers noted that while the shortages may not have been noticeable from a treatment perspective, they may have come at personnel and psychic costs not measured by the study. "This study only measured one dimension of oncology drug shortages: the effect on utilization," said Jacobson.

Increasing oncology drug shortages raised alarms

The number of prescription drug shortages in the United States increased from 71 in 2005 to 255 in 2011, and shortages of oncology drugs more than doubled during that time period. Oncology drug shortages in particular have generated substantial attention from the media and policymakers because of concerns about treatment gaps and inadequate dosing. For cancers in which certain treatments are clinically preferred or no alternative exists, drug shortages may be life-threatening.

Until now, no studies have systematically analyzed the consequences of shortages nationwide. Using data from the Surveillance, Epidemiology, and End Results (SEER) cancer registries linked with Medicare claims, Jacobson and colleague Abby Alpert with the University of Pennsylvania set out to provide a more general analysis of the impact of oncology drug shortages on outpatient chemotherapy treatment.

Millions of claims, thousands of patients, null impact on chemotherapy

Jacobson and Alpert studied more than 2.4 million monthly claims for chemotherapy treatment administered in a physician's office or outpatient hospital or clinic setting over a seven-year period. The claims were from 182,470 Medicare beneficiaries newly diagnosed with seven common cancers, including breast, colorectal, leukemia, lung, lymphoma, ovarian and pancreatic cancer.

The newly diagnosed sample represented 60 percent of total chemotherapy claims in the SEER-Medicare data. One in three chemotherapy claims for the newly diagnosed were for drugs that were on shortage during the study period.

The study found little impact on outpatient chemotherapy treatment for the majority of oncology drugs identified as experiencing shortages between 2004 and 2011. Even among the most commonly used chemotherapy drugs-- those ranked in the top 25 prescribed drugs in the sample--researchers found almost no change in treatment during shortages, including minimal effect on dosing volume.

The portion of patients receiving treatments declined for six drugs, including generic drugs that have been on the market for decades. "It seems that when some drugs become older and very low cost, there is not as much investment in making sure they are available," said Jacobson.

Possible explanations

Researchers say one explanation for the findings is that most oncology drug shortages have been effectively managed to minimize the effects on treatment. "Although a shortage may reflect a complete disruption of production, providers may be able to draw from existing inventories, purchase from providers who have higher projected inventory, or stockpile in advance if a shortage is anticipated," said Jacobson.

A second explanation is that rapid or timely production increases, sometimes at the request of the FDA, could have mitigated the impact of shortages on chemotherapy treatment. In some cases, temporary FDA allowance of importation of unapproved foreign versions of scarce drugs may have further eased the effects of shortages.

Next, the authors say the database considered the gold standard for dating shortages (UUDIS) may be capturing many shortages that would not be expected to impact treatment. The database includes on its shortage list any supply disruption that affects "how a pharmacy prepares or dispenses a drug product or that influences patient care when prescribers must use an alternative agent."

For example, if a larger vial size of the drug were unavailable, this would be classified as a shortage even if smaller package sizes were in supply and met patient demand. Although this type of supply disruption might require additional pharmacy resources, its impact on treatment might be minimal. It is unclear how many of the UUDIS shortages fit this description, however, the findings of minimal shortage impacts suggest that many may belong in this category.

Finally, researchers say the findings may be due to SEER-Medicare data limitations. The large sample size captures few nonelderly patients with cancer, and therefore may understate the effect of shortages on drugs, such as mechlorethamine, used to treat cancers that primarily affect younger populations. In addition, since SEER covers only a limited set of geographic areas, the data may miss regions that are harder hit by shortage.

How can drug shortages be mitigated?

"A key challenge moving forward is how to separately identify those cases that will result in clinically relevant shortages from those that are relatively easy to manage," said Jacobson. "A discussion of the intended use for, and limitations of the UUDIS and the FDA drug shortage lists would improve decision making by policymakers and physicians and the public discussion of drug shortages."

The authors say alternative approaches to tracking shortages and measuring their effects on treatment may be warranted to facilitate the early identification and mitigation of clinically relevant shortages.

Orlando, Fla. (April 7, 2019)--Device-guided breathing may improve physiological symptoms in people with severe posttraumatic stress disorder (PTSD), according to a new study. The findings will be presented today at the American Physiological Society's (APS) annual meeting at Experimental Biology 2019 in Orlando, Fla.

PTSD is a mental health condition that may develop after a person has experienced a traumatic or life-threatening event, including military combat, natural disasters and physical or sexual abuse. Flashbacks, nightmares and severe anxiety associated with PTSD can lead to episodes of rapid breathing, muscle tension and short-term increases in heart rate and blood pressure. The physical manifestations of PTSD can increase the long-term risks of hypertension and heart disease.

Researchers from Emory University in Atlanta explored the use of device-guided breathing to regulate sympathetic nerve activity--a nervous system response that regulates small changes to the cardiovascular system--and blood pressure control in military veterans with PTSD. The research team confirmed diagnosis and severity of PTSD in each volunteer using the Clinician-Administered PTSD Scale (CAPS). Volunteers were then divided into two groups--moderate or severe--based on their CAPS results. Within each group, the participants were randomly assigned to the breathing device (RESPeRATETM) or sham (fake) device.

RESPeRATE produces musical tones to guide the user to a slower-than-normal rate of breathing of about five to six breaths per minute. The device measures inhalation and exhalation rates through a band of sensors worn around the abdomen. The sham device works similarly, but guides the user to breathe 14 breaths per minute, which is within a normal range.

The researchers found that heart rate and muscle sympathetic nerve activity (MSNA) decreased substantially in the severe PTSD group using the breathing device when compared to the device-using moderate group. The volunteers with moderate PTSD who used RESPeRATE also showed an improvement in these factors, but the positive changes were not as significant as the people with more severe PTSD.

"A non-pharmacological intervention [such as device-guided breathing] could be beneficial in the treatment of PTSD, especially in severe cases. Further work is needed to determine if [device-guided breathing] could reduce the risk of future hypertension in this population," wrote Monica Vemulapalli, first author of the study. If device-guided breathing can lead to sustained reductions in MSNA, then it could potentially reduce risk of hypertension.

Orlando, Fla. (April 6, 2019) - Despite decades of fascination with dolphins, scientists have long overlooked one aspect of the species' anatomy. For the first time, researchers offer an up-close look at the clitoris of female dolphins along with insights on the potential for the animals to experience sexual pleasure.

The scientists discovered that female bottlenose dolphins have large and well-developed clitorises. The structure of the tissue suggests the clitoris may expand, for example, in response to stimulation. The skin under the clitoral hood contains bundles of nerves that may increase sensitivity and the potential for pleasure, as has been found in the human clitoris.

Previous studies suggest sex plays an important role in social bonding among dolphins, as seen in other social species. Dolphins copulate year-round, including during periods when they cannot conceive.

"In other mammalian species with year-round copulation, such as humans and bonobos, sex is known to be pleasurable for females, often through clitoral stimulation that leads to orgasm," said Dara Orbach, PhD, research associate at Mount Holyoke College, who conducted the research along with Assistant Professor of Biology Patricia Brennan, PhD. "Our anatomical observations suggest the clitoris is functional in bottlenose dolphins, but further research, including physiological and behavioral analyses, are necessary to test if sexual experiences can be pleasurable for female dolphins."

Orbach will present the research at the American Association of Anatomists annual meeting during the 2019 Experimental Biology meeting, held April 6-9 in Orlando, Fla.

The researchers studied 11 dolphins that had died naturally and were collected under a permit authorized by the National Marine Fisheries Service. To explore the anatomy of the dolphin clitoris, they performed dissections, created 3-D computed tomography (CT) scans, fixed the tissues in paraffin wax and stained them to examine their structure in detail.

They found that dolphins have a clitoral hood where two areas of extensive erectile tissue merge into a single body, a shape and structure very similar to the human clitoris. In both humans and dolphins, the erectile tissue of the clitoris is larger than the clitoral hood, and the thin, folded nature of the skin around the clitoral hood suggests the dolphin clitoris may expand during periods of engorgement and increased sensitivity.

However, the dolphin clitoris is located in a different position relative to the vaginal opening than in humans. "In dolphins, the clitoris is positioned at the entrance of the vaginal opening and in direct contact with the penis during copulation, unlike the external position of the clitoris in humans," said Orbach. "The location of the clitoris near the vaginal opening indicates it can potentially be easily stimulated during copulation."

In another contrast with human anatomy, the researchers did not find in the bottlenose dolphins any evidence of a vestibular bulb, an area of erectile tissue that surrounds the vaginal opening in humans and contributes to orgasm.

"Very little is known about female reproductive morphology in most wild vertebrate species," said Orbach. "This research provides a comparative framework to explore other functions of sex that may not be unique to humans. We are on the precipice of a deeper understanding of the relationship between form and function of genitalia."

Dara Orbach will present this research on Saturday, April 6, from 11:15-11:30 a.m. in Room W208A, Orange County Convention Center (abstract). Contact the media team for more information or to obtain a free press pass to attend the meeting.

In a collaboration between the U.S. Department of Energy's Ames Laboratory and Northeastern University, scientists have developed a model for predicting the shape of metal nanocrystals or "islands" sandwiched between or below two-dimensional (2D) materials such as graphene. The advance moves 2D quantum materials a step closer to applications in electronics.

Ames Laboratory scientist are experts in 2D materials, and recently discovered a first-of-its-kind copper and graphite combination, produced by depositing copper on ion-bombarded graphite at high temperature and in an ultra-high vacuum environment. This produced a distribution of copper islands, embedded under an ultra-thin "blanket" consisting of a few layers of graphene.

"Because these metal islands can potentially serve as electrical contacts or heat sinks in electronic applications, their shape and how they reach that shape are important pieces of information in controlling the design and synthesis of these materials," said Pat Thiel, an Ames Laboratory scientist and Distinguished Professor of Chemistry and Materials Science and Engineering at Iowa State University.

Ames Laboratory scientists used scanning tunneling microscopy to painstakingly measure the shapes of more than a hundred nanometer-scale copper islands. This provided the experimental basis for a theoretical model developed jointly by researchers at Northeastern University's Department of Mechanical and Industrial Engineering and at Ames Laboratory. The model served to explain the data extremely well. The one exception, concerning copper islands less than 10 nm tall, will be the basis for further research.

"We love to see our physics applied, and this was a beautiful way to apply it," said Scott E. Julien, Ph.D. candidate, at Northeastern. "We were able to model the elastic response of the graphene as it drapes over the copper islands, and use it to predict the shapes of the islands."

The work showed that the top layer of graphene resists the upward pressure exerted by the growing metal island. In effect, the graphene layer squeezes downward and flattens the copper islands. Accounting for these effects as well as other key energetics leads to the unanticipated prediction of a universal, or size-independent, shape of the islands, at least for sufficiently-large islands of a given metal.

"This principle should work with other metals and other layered materials as well," said Research Assistant, Ann Lii-Rosales. "Experimentally we want to see if we can use the same recipe to synthesize metals under other types of layered materials with predictable results."

Scientists from the RIKEN Cluster for Pioneering Research and collaborators have used simulations to show that the photons emitted by long gamma-ray bursts--one of the most energetic events to take place in the universe--originate in the photosphere--the visible portion of the "relativistic jet" that is emitted by exploding stars.

Gamma-ray bursts are the most powerful electromagnetic phenomenon observed in the universe, releasing as much energy in just a second or so as the sun will release over its entire lifetime. Though they were discovered in 1967, the mechanism behind this enormous release of energy long remained mysterious. Decades of studies finally revealed that long bursts--one of the types of bursts--originate from relativistic jets of matter ejected during the death of massive stars. However, exactly how the gamma-rays are produced from the jets is still veiled in mystery today.

The current research, published in Nature Communications, began from a discovery called the Yonetoku relation, which was originally made by one of the authors of the paper. This relation between the spectral peak energy and peak luminosity of GRBs is the tightest correlation found so far in the properties of GRB emission. It thus provides the best diagnostic so far for explaining the emission mechanism, and the strictest test for any model of gamma-ray bursts. Incidentally, the relationship also meant that long gamma-ray bursts could be used as a "standard candle" for measuring distance, allowing us to peer further into the past than type 1A supernovae, which are commonly used today but are much dimmer than the bursts. This would make it possible to gain insights into the history of the universe, and could give us insights into mysteries such as dark matter and dark energy.

Using computer simulations performed on several supercomputers, including Aterui of the National Astronomical Observatory of Japan, Hokusai of RIKEN, and Cray xc40 of the Yukawa Institute for Theoretical Physics, the group focused on the so-called "photospheric emission" model, one of the leading models for the emission mechanism of GRBs. This model postulates that the photons visible on earth are emitted from the photosphere of the relativistic jet. As the jet expands, it becomes easier for photons to escape from within it, since there are fewer objects available to scatter the light. Thus, the "critical density" --the place where it becomes possible for the photons to escape-- moves downward through the jet, to material that was originally at higher and higher densities.

To test the validity of the model, the team set out to test it in a way that took into account the global dynamics of relativistic jets and radiation transfer. By using a combination of three-dimensional relativistic hydrodynamical simulations and radiation transfer calculations to evaluate photospheric emissions from a relativistic jet breaking out of massive star envelope, they were able to determine that at least in the case of long GRBs--the type associated with such collapsing massive stars--the model worked. Their simulations revealed that the Yonetoku relation could be reproduced as a natural consequence of the jet-stellar interactions. "To us," says Hirotaka Ito of the Cluster for Pioneering Research, "this strongly suggests that photospheric emission is the emission mechanism of GRBs."

He continues, "While we have elucidated the origin of the photons, there are still mysteries concerning how the relativistic jets themselves are generated by the collapsing stars. Our calculations should provide valuable insights for looking into the fundamental mechanism behind the generation of these tremendously powerful events."

ORLANDO, Fla., April 3, 2019 -- Science-fiction writers have long envisioned human¬-machine hybrids that wield extraordinary powers. However, "super plants" with integrated nanomaterials may be much closer to reality than cyborgs. Today, scientists report the development of plants that can make nanomaterials called metal-organic frameworks (MOFs) and the application of MOFs as coatings on plants. The augmented plants could potentially perform useful new functions, such as sensing chemicals or harvesting light more efficiently.

The researchers will present their results today at the American Chemical Society (ACS) Spring 2019 National Meeting & Exposition. ACS, the world's largest scientific society, is holding the meeting here through Thursday. It features nearly 13,000 presentations on a wide range of science topics.

A brand-new video on the research is available at http://bit.ly/HLS_Plants.

According to the project's lead researcher, Joseph Richardson, Ph.D., humans have been introducing foreign materials to plants for thousands of years. "One example of this is flower dyeing," he says. "You'd immerse a cut flower stem into some dye, and the dye would be taken up through the stem and penetrate into the flower petals, and then you'd see these beautiful colors."

Because of their extensive vascular networks, plants readily absorb water and molecules dissolved in fluids. However, it's more difficult for larger materials and nanoparticles such as MOFs to penetrate roots. So Richardson and colleagues at the University of Melbourne (Australia) wondered if they could feed plants MOF precursors, which the plants would absorb and then convert into finished nanomaterials.

MOFs -- which consist of metal ions or clusters linked to organic molecules -- form highly porous crystals that can sop up, store and release other molecules, much like a sponge. Chemists have made thousands of different MOFs so far, with potential applications ranging from storing hydrogen fuel to absorbing greenhouse gases to delivering medications within the body. Having plants make small amounts of these useful compounds in their own tissues could give them new abilities not seen in nature.

To see whether plants could make MOFs, Richardson and colleagues added metal salts and organic linkers to water and then placed cuttings or intact plants into the solution. The plants transported the precursors into their tissues, where two different types of fluorescent MOF crystals grew. In a proof-of-concept experiment, MOF-producing lotus plant clippings detected small concentrations of acetone in water, as shown by a decrease in fluorescence of the materials. Based on these results, Richardson plans to explore whether plant-MOF hybrids could sense explosives or other volatile chemicals, which could be useful for airport security.

In addition to having the plants make MOFs, the finished materials could be used as a coating on the plants to help them convert harmful ultraviolet (UV) rays into light that's more useful for photosynthesis. "As we contemplate growing crops in space or on Mars where you don't have an atmosphere and are bombarded by UV rays, something like this could be helpful," Richardson says. "That's because it not only protects the plants from the UV rays, but it also turns them into useful energy. Especially as you get farther away from the sun, it's harder to capture all of the light you'd need for photosynthesis."

The researchers have already started examining the protective abilities of the nanomaterials, and the preliminary data are promising. The team coated clippings of chrysanthemum and lilyturf with luminescent MOFs and then exposed the plants to UVC light for three hours. Compared with uncoated clippings, the plants with MOFs showed less wilting and bleaching.

Now, Richardson is teaming up with plant biologists to study the effects of MOFs on plant growth. So far, they haven't noticed any toxicity of the nanomaterials. The researchers also want to explore whether MOFs could actually help plants grow better, which may lead to applications in agriculture.

A press conference on this topic will be held Wednesday, April 3, at 9:30 a.m. Eastern time in the Orange County Convention Center. Reporters may check-in at the press center, Room W231B, or watch live on YouTube http://bit.ly/ACSLive_Orlando2019 ("ACSLive_Orlando2019" is case sensitive). To ask questions online, sign in with a Google account.

Researchers at Washington University in St. Louis have discovered and characterized a new form of oxygen dubbed "featherweight oxygen" -- the lightest-ever version of the familiar chemical element oxygen, with only three neutrons to its eight protons.

Oxygen is one of the most abundant elements in the solar system, but oxygen-11 can be produced only in a laboratory. It decays immediately after its creation by emitting two protons, and it can be observed solely through detection of its decay products. Two-proton decay is the most recently discovered nuclear decay channel.

"What is most interesting to the nuclear physics community, however, is that oxygen-11 is the nuclear mirror of lithium-11, a very well-studied heavy isotope of lithium," said Tyler Webb, a PhD candidate in physics in Arts & Sciences at Washington University, who works with Robert J. Charity, research professor of chemistry in Arts & Sciences, and Lee G. Sobotka, professor of chemistry and of physics. Webb is the first author of a new paper on the discovery in Physical Review Letters.

In nuclear physics, nuclei are said to be mirrors when one has a certain number of neutrons and protons and the other has a reversed amount, such as the 3:8 ratio of neutrons to protons in oxygen-11 as compared to the 8:3 ratio in lithium-11.

"When talking about mirror nuclei, we expect a sort of symmetry to hold," Webb said. "The properties of a nucleus and its mirror should be similar: Quantum states should be roughly close in energy relative to the nucleus's ground state and the wave functions of those states should be similar."

This symmetry can be stretched or broken, however. Scientists can compare the actual structure of mirror nuclei against their expected structure to learn more about this important symmetry of atomic nuclei, the stuff that composes the visible matter of the universe.

In this case, the researchers are most excited to compare lithium-11, which they know has two very loosely bound neutrons in a "halo" orbiting its core, to oxygen-11, which has two unbound protons.

The Washington University researchers pieced together evidence of oxygen-11 in an experiment conducted at the National Superconducting Cyclotron Laboratory on the campus of Michigan State University. The Physical Review Letters paper outlines both the experiment and the supporting calculations conducted by theoretical nuclear physicists Witold "Witek" Nazarewicz and Simin Wang of Michigan State University. Researchers from University of Connecticut and Western Michigan University also participated in the collaboration.

HOKKAIDO, JAPAN (March 29, 2019) - Paleontologists from Hokkaido University in Japan, in cooperation with paleontologists from the Perot Museum of Nature and Science in Dallas, Texas, have discovered the first-confirmed occurrence of a lambeosaurine (crested 'duck-billed' dinosaur) from the Arctic - part of the skull of a lambeosaurine dinosaur from the Liscomb Bonebed (71-68 Ma) found on Alaska's North Slope. The bonebed was previously known to be rich in hadrosaurine hadrosaurids (non-crested 'duck-billed' dinosaurs).

The discovery proves for the first time that lambeosaurines inhabited the Arctic during the Late Cretaceous. In addition, the numeric abundance of hadrosaurine fossils compared to the lambeosaurine fossils in the marine-influenced environment of the Liscomb Bonebed suggests the possibility that hadrosaurines and lambeosaurines had different habitat preferences.

The paleontologists' findings were published today in Scientific Reports, an open-access, multi-disciplinary journal from Nature Research dedicated to constructive, inclusive and rigorous peer review. The paper - entitled "The first definite lambeosaurine bone from the Liscomb Bonebed of the Upper Cretaceous Prince Creek Formation, Alaska, United States" - is co-authored by Yoshitsugu Kobayashi, Ph.D., and Ryuji Takasaki, of Hokkaido University, in cooperation with Anthony R. Fiorillo, Ph.D., of the Perot Museum of Nature and Science. Other authors are Ronald Tykoski, Ph.D. of the Perot Museum and Paul McCarthy, Ph.D., of the University of Alaska.

The paper can be read in Scientific Reports here.

"This new discovery illustrates the geographic link between lambeosaurines of North America and the Far East," said Takasaki. "Hopefully, further work in Alaska will reveal how closely the dinosaurs of Asia and North America are connected."

The newly discovered fossil, which is housed in the collections of the Perot Museum of Nature and Science, is a supraoccipital, one of the bones that forms the braincase. The new supraoccipital differs from those of hadrosaurines by the presence of large supraoccipital bosses and it's short, front-to-back length. Since these features are commonly seen in other members of Lambeosaurinae, the newly discovered supraoccipital was assigned to that group.

"This first definitive evidence of a crested hadrosaur in the Cretaceous Arctic tells us that we still have much to learn about the biodiversity and the biologically productive environments of the ancient north, and that the story these fossils tell us is continually evolving," adds Dr. Fiorillo.

Background. The Arctic is an extreme environment that is low in temperature, lacks sunlight during winters, and has seasonally limited food resources. Though it was warmer during the Late Cretaceous, the Arctic was surely one of the most challenging places to live for large vertebrates at the time. The Prince Creek Formation on the North Slope of Alaska is a world-famous rock unit for studying dinosaurs of the ancient Arctic. Because the dinosaurs found there lived in the ancient Arctic, rather than tropical or sub-tropical conditions, these dinosaurs challenge much of what we think we know about dinosaurs. The Liscomb Bonebed (71-68 Ma), which was deposited near the ancient Arctic shoreline, is especially rich in dinosaur bones, with more than 6,000 bones collected from it thus far.

More than 99% of dinosaur fossils known from the Liscomb Bonebed are hadrosaurs, a group of large, duck-billed herbivorous dinosaurs who lived during the Late Cretaceous and were found throughout much of the northern hemisphere. All of the hadrosaur fossils from the Liscomb Bonebed were long considered to belong to a hadrosaurine duck-billed dinosaur called Edmontosaurus. Up until now, all of the hadrosaurids known from across the Arctic, including those from the Liscomb Bonebed, were considered to belong to crest-less hadrosaurines.

The discovery of a fossil from a lambeosaurine hadrosaurid in the Liscomb Bonebed is historically important for Japanese paleontologists. The first "Japanese" dinosaur, Nipponosaurus, is a lambeosaurine hadrosaur. Based on the new discovery, Hokkaido University and the Perot Museum together used this discovery to further investigate the ecology of the Arctic hadrosaurids.

Significance

1. The first Arctic lambeosaurine. The new discovery indicates Arctic inhabitance and adaptation of lambeosaurines for the first time. In addition, the fossil's morphological similarities to the same bone in the skull of southern Canadian lambeosaurines suggest faunal interactions between the Arctic and the mid-latitudes.

2. Implication on habitat preferences. While the Liscomb Bonebed is known for numerous hadrosaurine fossils, the newly discovered bone represents the only definite lambeosaurine fossil from the site. The same trend is also known in mid-latitude localities of North America and eastern Asia, which were also deposited in near-shore environments. On the other hand, more lambeosaurine fossils are found in deposits laid down in inland environments. Therefore, we hypothesize that lambeosaurines favored inland environments, while hadrosaurines preferred coastal environments, a trend likely to have been independent of latitude. Different habitat preferences might have been a strategy to avoid excessive competition between the two groups of 'duck-billed' dinosaurs.

Future plans. Although the new discovery reveals Arctic inhabitance by lambeosaurines, more specific taxonomic status and potential functional adaptations to the severe Arctic environment remain unknown due to incompleteness of the specimen. Additional excavation and further research will help answer these questions.

White individuals disproportionately affect the environment through their eating habits by eating more foods that require more water and release more greenhouse gases through their production compared to foods black and Latinx individuals eat, according to a new report published in the Journal of Industrial Ecology.

The report takes an in-depth look at what different demographic populations eat, how much greenhouse gas those foods are responsible for, and how much land and water they require. The study was undertaken to get a better understanding of the environmental impacts of the food consumption patterns of major demographic groups so that environmental policies designed to reduce negative impacts of food production could be drafted that take these differences into account.

"The food pipeline - which includes its production, distribution and waste - contributes significantly to climate change through the production of greenhouse gases and requires significant amounts of water and land, which also has environmental effects," said Joe Bozeman, a student in the University of Illinois at Chicago Institute for Environmental Science and Policy and first author on the paper. "If we are to draft policies related to food, they can't be one-size-fits-all policies because different populations have different eating patterns which have their own unique impacts on the environment."

Bozeman and his colleagues analyzed data from The U.S. Environmental Protection Agency's What We Eat in America - Food Commodity Intake Database - which provides per capita food consumption estimates for more than 500 types of food (such as apples, poultry, bread) as well as water - and from the National Health and Nutrition Examination Survey, which provides estimates of individual dietary intake. Estimates of the environmental impact of these foods were obtained from various databases and from the scientific literature. Foods considered 'environmentally intense,' include those that require more water, land and energy and produce more greenhouse gases than other foods. Apples, potatoes, beef and milk are among the most environmentally intense foods.

According to their analysis, the researchers found that white individuals produced an average of 680 kilograms of the greenhouse gas carbon dioxide each year that can be directly linked to what they ate and drank, while Latinx individuals produced 640 kilograms of carbon dioxide and blacks produced 600 kilograms of carbon dioxide each year. "While the difference may not be enormous, these numbers are per individual, and when you add up all those individuals, it's very clear that whites are responsible for the majority of greenhouse gases emitted as a result of their food choices," Bozeman said.

The researchers also found that the food habits of white people require about 7 percent more water at 328,000 liters per year than Latinx individuals whose food habits require 307,000 liters per year of water, while black's eating habits depend on about 12 percent more land than other populations, which Bozeman says is driven in part by their higher consumption of chicken and apples, which are high land-use food items. "Whites tend to drink more water and milk. Milk itself requires a lot of water to produce when you consider livestock cultivation, so that is part of what we think is pushing their water impacts higher."

Policies that attempt to reduce resource dependence or greenhouse gases need to also take into account individual nutrients, says Bozeman. "If you are going to draft policies that may reduce the amount of land-intensive oranges, we need to think about other less resource-intensive sources of vitamin C. It gets more complex as you look closely at the food pipeline and how different populations engage with it, but we are now starting to get a better understanding on these complex dynamics in such a way that we can begin to rationally take steps to improve environmental quality."

A team of biologists and physicists, led by the University of Bristol, have uncovered new insights into how antlions - one of the fiercest and most terrifying predators in the insect kingdom - build their deadly pit traps.

Antlions - with their nightmarish fish-hook sharp jaws which can drain the bodily fluids of its victims within minutes - are iconic within entomology and they have been studied for 200 years.

It was known that they make pits lined with fine sand grains and that they throw large debris out of the pit.

But during their field work, the researchers were amazed at how thorough this is - so much so that even slightly larger sand grains are ejected.

They performed an experiment in which they gave antlions a mixture of large and small sand grains and captured and separated all of the grains thrown out of the pit.

Vastly more large sand grains were thrown out than would ever have occurred in the volume of sand that could have occupied the space that became the pit.

Professor Nigel Franks from the University of Bristol's School of Biological Sciences, said: "It is almost like a conjuring trick - many more large grains are ejected than seems possible.

"One answer is that the antlion is "interrogating" much more sand to find and eject large grains than just the volume of sand that has to be removed to form the final pit."

How this is achieved lies is some physical processes that were only discovered a couple of decades ago.

The research team consulted physicists Kim Christensen and Max Falkenberg at Imperial College, London, who have unrivalled expertise when it comes to the strange properties of granular mixtures.

Together they formulated a computational model, mimicking an antlion digging in granular mixtures, to gain insight into the processes and the reasons why they employ spiral digging.

Professor Franks added: "This technique is a superbly efficient time-saving method that literally enables antlions to plough through a large volume of sand such that the small avalanches they create cause large sand grains differentially to cascade to the bottom of the construction trench where they can be preferentially ejected during pit construction."

Most animal traps use silk as in spider webs. But spider silk is secreted whereas antlions only use materials they find in their environment.
Nevertheless, spider webs and antlion pits are both superb examples of extended phenotypes.

They can be seen as an extension of their builder's body optimised by natural selection. What this research has shown is that extended phenotypes produced purely from found materials can be not only efficiently constructed but extremely efficient in operation.

By lining their pits with fine slippery sand grains, the antlions make their pits extremely avalanche-prone.

Professor Franks added: "Any prey item that ventures into the pit will ride an avalanche down to the deadly antlion at the bottom of the pit. Such pits are an intriguing example of the ever-present force of natural selection that shapes biology."