Tech

WASHINGTON, March 23, 2020 -- Refreshable braille displays translate information from computer screens into raised characters, often along the bottom of a keyboard. But this technology can cost thousands of dollars and is limited, typically displaying a string of characters much shorter than most sentences. Researchers now report an improved material that could take these displays to the next level, allowing those who are blind or who have low vision to more easily understand text and images, while lowering cost.

The researchers are presenting their results through the American Chemical Society (ACS) SciMeetings online platform.

"With more development, we think this new material's properties could make it possible to create much higher resolution devices, perhaps even those capable of displaying information other than text, such as diagrams or maps," says Julia R. Greer, Ph.D., the project's principal investigator.

Braille displays currently on the market rely on the piezoelectric effect: A small crystal expands when voltage is applied to it, pushing a pin upward to create a dot. A single character, such as a letter, is encoded by up to eight such dots. Devices on the market typically display at most 80 characters at a time, or a fraction of a sentence or tweet.

Researchers have recently turned their attention to electroactive polymers (EAPs) as a type of material that could improve these displays. EAPs could display much more information than conventional devices, as well as a greater diversity of it. What's more, the devices could be easier and cheaper to manufacture. That promise has yet to materialize, however, and EAP-based displays have encountered many issues, including the need for high voltage to operate and poor durability.

Greer's team at the California Institute of Technology (Caltech) conceived of an entirely new type of EAP based on polyionic complexes, and in the summer of 2019, the group began working on a way to synthesize the material. An improved EAP could help braille technology catch up to that used by those with sight, says Rob Learsch, who was a graduate student in the lab at the time. "Braille technology hasn't changed much since the 1980s," he notes. "I think it would be remarkable to allow everyone to benefit from the revolution in miniaturization and computation that has occurred."

Whereas conventional EAPs rely on electrical charge accumulating on electrodes, the new material contains positively and negatively charged polymers combined into a random network of chains connected at nodes. The negatively charged polymers form a solid scaffold to which the positive ones bind, acting like rubber bands that pull everything together. Applying an electrical field unravels these connections, as if cutting the rubber bands, and causes the material to expand outward. The polyionic EAP requires much less voltage, and is more efficient and resilient, than conventional EAPs.

Learsch has since joined the lab of Julia Kornfield, Ph.D., at Caltech, where he and others are continuing to study the material's properties and develop it to the point where it can be used within braille displays and, perhaps, offer new functionality for these devices. Because the material can act like a capacitor, generating an electrical signal when pressure is applied, it could be used to build braille displays that respond to touch, much like the screen of a smart phone or tablet.

The material also could be used for other applications. If controlled by precise electrical fields, Learsch says he could foresee it opening and closing a robotic joint or gripper. "There is a lot of research to be done to get us from where we are now to these types of products, but that is all part of our long-term vision," Learsch says.

Dr. Soon Moon Jeong's research team in the Division of Energy Technology at DGIST has developed a new structure of luminescence technology. This will enable the production of light-emitting elements that overcome the limitations of existing methods, expecting to greatly help improve the efficiency of light-emitting elements used in various ways such as billboards and banners.

Light emitting devices need electrodes to transmit energy to the light emitting layer. The 'flat electrode' used here is an electrode consists of a coplanar structure surrounding the light emitting layer, which has limitation as the light emitted from the light emitting layer is blocked by the electrode. The decreasing flexibility of the electrodes was also an obstacle to manufacturing a flexible light emitting device that emits light constantly.

To overcome these limitations, Dr. Jeong's team cross-inserted a new type of electrode made of fibers inside the light emitting layer unlike existing light emitting devices, through which they could develop a new light-emitting technology using an in-plane electric field generated in parallel to the light-emitting layer. The light-emitting device produced this way improved efficiency significantly by emitting light more flexibly and stably than the existing light-emitting devices.

Dr. Jeong's research team applied a new luminescent film using zinc sulfide (ZnS) and polydimethylsiloxane (PDMS) to the luminescent layer while using the in-plane electric field. Through this, they made possible at the same time the mechanoluminescence (ML) which generates light by applying mechanical force and electroluminescence (EL) which generates light by operating the electric field. While it was not possible in the conventional light emitting devices, this new technology could maintain constant and efficient light intensity in various environments.

The light-emitting device developed this time provided important clues to overcome various limitations of the existing light-emitting device. First, the structure of light emitting device developed by Dr. Jeong's team solved the problem of the existing light emitting device in which electrodes are inserted into the light emitting layer and block light. By doing so, the research team also solved at once the disadvantage that thick electrodes needed to further increase the light intensity of light emitting device rather blocking the light of the light emitting layer between them.

Dr. Jeong in the Division of Energy Technology said "We want to change the paradigm of related industries in the future through the development of devices that emit light constantly, despite any changes of forms. This is definitely possible if we improve the light emitting device further, and it is expected to be used in various forms of light emitting textile and wearable devices."

This research finding was published on the latest issue of Materials Today, a world-renowned international journal in materials engineering. This research was conducted with the support of DGIST and the mid-carrier researcher support project carried out by the Ministry of Science and ICT.

Research shows that physical and sexual abuse are risk factors for depression in adolescents. However, we know less about the differences between emotional abuse and neglect as critical risk factors in teenage depression. A new longitudinal study examined the depressive effects of these different types of maltreatment among a group of youth at risk of being maltreated. The study found that emotional abuse and neglect affect adolescent depression differently depending on gender and ethnicity.

The findings come from researchers at the University of Illinois at Urbana-Champaign and the University of Nebraska-Lincoln. They appear in Child Development, a journal of the Society for Research in Child Development.

"Emotional abuse and emotional neglect have different impacts on adolescent depression," explains Joseph Cohen, assistant professor of psychology at the University of Illinois at Urbana-Champaign, one of the study's authors. "Even though both types of maltreatment predict depression, they may predict depression for different reasons. Furthermore, female teenagers may be more sensitive to emotional abuse, while the impact of emotional neglect may differ based on the adolescent's racial or ethnic identity. Understanding how different youth are affected by different parenting behaviors can lead to more personalized, trauma-informed interventions."

Researchers used self-reports from 657 youth ages 11 to 14 years from a range of racial and ethnic backgrounds. The youth were part of the National Survey of Child and Adolescent Well-Being, a nationally representative longitudinal study to evaluate the outcomes of children who had Child Protective Services investigations for child abuse or neglect closed during a 15-month period beginning in February 2008 in the United States.

The teenagers were initially assessed on emotional maltreatment, relationships with peers (including feelings of loneliness and social dissatisfaction in relationships with other youth), school engagement (the extent to which students participated in the academic and nonacademic activities of school, and felt connected at school), and depression. They were assessed again 18 months and 36 months later. Emotional abuse was defined as parental psychological aggression and emotional neglect was defined as parental noninvolvement.

The study found that both psychological aggression and parental noninvolvement were related to depression in the adolescents. Psychological aggression predicted an increase in symptoms of depression through increasing problems associated with peer relationships, especially for girls. The study also found that decreasing school engagement mediated the relation between parental noninvolvement and increasing symptoms of depression, but only for Hispanic adolescents.

The study's authors acknowledge limitations to their work: the study assessed teenagers through self-reports, including the assessment of emotional abuse and neglect. They suggest that in the future, researchers should leverage the strengths of a multimethod approach (e.g., parent reports, administrative data) to provide a more comprehensive picture of how different forms of emotional maltreatment may manifest and predict depression. In addition, the 18-month gap between follow-up assessments prevented researchers from detecting fluctuations in symptoms in briefer intervals.

"Current clinical services and policies are more focused on abuse than maltreatment," says Shiesha McNeil, a doctoral student in psychology at the University of Illinois at Urbana-Champaign, who coauthored the study. "By articulating the consequences of emotional neglect for different genders and ethnicities, we can develop better ways to address maltreatment and alleviate depression."

Washington, DC-- Carbon is essential for life as we know it and plays a vital role in many of our planet's geologic processes--not to mention the impact that carbon released by human activity has on the planet's atmosphere and oceans. Despite this, the total amount of carbon on Earth remains a mystery, because much of it remains inaccessible in the planet's depths.

New work published this week in Proceedings of the National Academy of Sciences reveals how carbon behaved during Earth's violent formative period. The findings can help scientists understand how much carbon likely exists in the planet's core and the contributions it could make to the chemical and dynamic activity occurring there--including to the convective motion powering the magnetic field that protects Earth from cosmic radiation.

Earth's core is comprised mostly of iron and nickel, but its density indicates the presence of other lighter elements, such as carbon, silicon, oxygen, sulfur, or hydrogen. It's been long suspected that there's a tremendous reservoir of carbon hiding down there. But to attempt to quantify it, the research team used laboratory mimicry to understand how it got into the core in the first place.

The group was comprised of Harvard University's Rebecca Fischer, the Smithsonian Institution's Elizabeth Cottrell and Marion Le Voyer, both former Carnegie postdoctoral fellows, Yale University's Kanani Lee, and Carnegie's late Erik Hauri, the memory of whom the authors acknowledge.

"To understand present day Earth's carbon content, we went back to our planet's babyhood, when it accreted from material surrounding the young Sun and eventually separated into chemically distinct layers--core, mantle, and crust," said Fischer. "We set out to determine how much carbon entered the core during these processes."

This was accomplished by lab experiments that compared carbon's compatibility with the silicates that comprise the mantle to its compatibility with the iron that comprises the core while under the extreme pressures and temperatures found deep inside the Earth during its formative period.

"We found that more carbon would have stayed in the mantle than we previously suspected," explained Cottrell. "This means the core must contain significant amounts of other lighter elements, such as silicon or oxygen, both of which become more attracted to iron at high temperatures."

Despite this surprising discovery, the majority of Earth's total carbon inventory does likely exist down in the core. But it still makes up only a negligible component of the core's overall composition.

"Overall, this important work improves our understanding of how Earth's carbon was accumulated during the planetary formation process and sequestered into the mantle and core as they chemically differentiated," concluded Richard Carlson, Director of Carnegie's Earth and Planets Laboratory, where Hauri worked. "I only wish Erik was still with us to see the results published this week."

While they can't pick out precise numbers, animals can comprehend that more is, well, more. From birds to bees and wolves to frogs, animals use numbers to hunt, find a mate, return to their home, and more--and researchers believe that this ability to process and represent numbers, known as numerical competence, plays an important role in how animals make these decisions and influences an animal's chance of survival. In a Review publishing March 30 in the journal Trends in Ecology and Evolution, Andreas Nieder, a neurobiologist at the University of Tuebingen, Germany, explores the current literature on how different animal species comprehend numbers and the impact on their survival, arguing that we won't fully understand the influence of numerical competence unless we study it directly.

"Interestingly, we know now that numerical competence is present on almost every branch on the animal tree of life," says Nieder, who works with different animal species to explore how trained animals discriminate and represent numbers as well as how numbers are represented in the brain. "Different groups of animals obviously developed this trait independently from other lineages and that strongly indicates that it has to be of adaptive value. So the capability to discriminate numbers has to have a strong survival benefit and reproduction benefit."

Honeybees, for instance, can remember the number of landmarks they pass when searching for food in order to find their way back to the hive. "The last common ancestor between honeybees and us primates lived about 600 million years ago," he says. "But still, they evolved numerical competence that, in many respects, is comparable to vertebrae numerical competence."

This can also be seen in animals choosing a larger amount of food over a small amount or in animals forming hunting alliances. Wolves are more likely to hunt successfully if they have the right number of wolves in their pack for the size of their prey: with prey like elk and moose, only around six to eight wolves are needed, while hunting bison requires a pack of nine to thirteen. Their prey also use this concept to protect themselves from predators--elk tend to live in smaller herds, which rarely have encounters with wolves, or gather in large herds to reduce the chance of any individual becoming prey. "So obviously they are assessing the number of individuals in their groups for their everyday life situations," Nieder says.

Furthermore, it has been shown that numerical competence even plays a role in attracting a mate. For example, male frogs sing "advertisement" calls to attract females. The females, listening for the complexity of their calls, choose the male that sings the most "chucks" in their mating call. Even once they've attracted a mate, species like the mealworm beetle and the cowbird use numerical competence to increase the likelihood of having offspring.

Despite these many examples of numerical competence in animals, this subject has not gotten many first-hand studies. "Many of these behavioral findings in the wild have usually been collected as by-products or accidental findings of other research questions," says Nieder.

Researchers do have some sense of the rules that govern numerical competence in animals, including that they count approximately rather than specifically and that two numbers need to be more different for them to tell them apart as those numbers get bigger--and it does seem apparent that those abilities are adaptive. However, Nieder argues that more research needs to be done to fully understand the selective pressures and fitness payoffs of numerical competence.

He also says that it is important to better understand the laws of perception and the underlying cognitive and neural machinery that goes into numerical competence, in order to understand how it drives fitness-related decisions. To that end, in the next year, Nieder and his lab will move toward researching how the brain and neurons process numbers in animals. "I hope I can encourage behavioral ecologists to specifically explore numerical competence in the wild, and, in doing so, also open new research fields," he says.

People continuously exposed to air pollution are at increased risk of dementia, especially if they also suffer from cardiovascular diseases, according to a study at Karolinska Institutet in Sweden published in the journal JAMA Neurology. Therefore, patients with cardiovascular diseases who live in polluted environments may require additional support from care providers to prevent dementia, according to the researchers.

The number of people living with dementia is projected to triple in the next 30 years. No curative treatment has been identified and the search for modifiable risk and protective factors remains a public health priority. Recent studies have linked both cardiovascular disease and air pollution to the development of dementia, but findings on the air pollution-link have been scarce and inconsistent.

In this study, the researchers examined the link between long-term exposure to air pollution and dementia and what role cardiovascular diseases play in that association. Almost 3,000 adults with an average age of 74 and living in the Kungsholmen district in central Stockholm were followed for up to 11 years. Of those, 364 people developed dementia. The annual average level of particulate matter 2.5 microns or less in width (PM2.5) are considered low compared to international standards.

"Interestingly, we were able to establish harmful effects on human health at levels below current air pollution standards," says first author Giulia Grande, researcher at the Department of Neurobiology, Care Sciences and Society at Karolinska Institutet. "Our findings suggest air pollution does play a role in the development of dementia, and mainly through the intermediate step of cardiovascular disease and especially stroke."

For the last five years of exposure, the risk of dementia increased by more than 50 percent per interquartile range (IQR) difference in mean PM2.5 levels and by 14 percent per IQR in nitrogen oxide. Earlier exposures seemed less important. Heart failure and ischemic heart disease both enhanced the dementia risk and stroke explained almost 50 percent of air pollution-related dementia cases, according to the researchers.

"Air pollution is an established risk factor for cardiovascular health and because CVD accelerates cognitive decline, we believe exposure to air pollution might negatively affect cognition indirectly," says Giulia Grande. "In our study, virtually all of the association of air pollution with dementia seemed to be through the presence or the development of CVD, adding more reason to reduce emissions and optimize treatment of concurrent CVD and related risk factors, particularly for people living in the most polluted areas of our cities.

New York City's pioneering Local Law 87 requires office and residential buildings to monitor their energy use, using detailed audits. In a study published today (March 30) in the research journal Nature Energy, Constantine E. Kontokosta, Danielle Spiegel-Feld and Sokratis Papadopoulos of New York University discuss the impact of this requirement on building owners, looking closely at detailed energy use and audit data between 2011 and 2016 from about 4,000 buildings. As a result of the law, the researchers found that energy use fell by a modest -2.5% for multifamily residential buildings and -4.9% for office buildings.

"The results suggest that mandatory audits, by themselves, create an insufficient incentive to invest in energy efficiency at the scale needed to meet citywide carbon-reduction goals," wrote the authors. “In the context of a comprehensive, data-driven energy policy, audit requirements can be used to target 'deep' retrofits, while automated or virtual audits could replace the existing need for traditional audit mandates.”

Energy use in existing buildings is responsible for an estimated 67% of all New York City carbon emissions, the authors wrote. More than 20 cities, including Austin, Chicago, and San Francisco, have adopted policies to increase data and transparency on energy use, seeking to encourage market interventions to reduce energy consumption and carbon pollution. New York City has led the way in this regard.

The New York University study seeks to inform urban energy policy decisions by comparing energy use in properties that have performed a mandatory energy audit with those that have not within New York City.

The article, titled "The impact of mandatory energy audits on building energy use," is co-authored by: Kontokosta, associate professor of urban science and planning, and director of the Civics Analytics program, NYU Marron Institute of Urban Management; Spiegel-Feld of the Guarini Center on Environmental, Energy and Land Use Law, NYU School of Law; and Papadopoulos, NYU Tandon's Department of Civil and Urban Engineering, and Center for Urban Science & Progress (CUSP).

The number of people diagnosed with psychiatric disorders in Ontario remained stable between 2002 and 2014, but the number of people self-reporting mental health issues and using mental health services has increased, according to a study in CMAJ (Canadian Medical Association Journal).

"These findings may indicate that because of increased awareness and reduced stigma around mental health issues, more people experiencing distress are seeking help," says Dr. Maria Chiu, a scientist with the Mental Health and Addictions Research Program, ICES and assistant professor, Institute of Health Policy, Management and Evaluation, University of Toronto, with coauthors.

The study included data on more than 260 000 Ontario residents who participated in Statistics Canada's Canadian Community Health Survey between 2002 and 2014. Self-reporting of fair or poor mental health status increased from 4.9% in 2003-2005 to 6.5% in 2011-2014, with a corresponding increase in use of mental health services from 7.2% to 12.8%.

"Self-reporting of physician-diagnosed mood disorders in the 2011-2014 period was more than one-and-a-half times higher than measured prevalence of major depression in 2012, which suggests that more people are saying they are depressed than are clinically measured," says Dr. Chiu

"While in the past people may have been suffering in silence, there are now more conversations about mental illness and people are seeking care," says Dr. Chiu. "Help-seeking is catching up with need."

However, the authors caution that increased use of mental health services could strain the health care system further, underscoring the need to improve access to care, especially for lower-income and other marginalized people.

A related commentary suggests Canada needs to look at international models and innovative approaches to scale up evidence-based psychotherapies to meet increased need. http://www.cmaj.ca/lookup/doi/10.1503/cmaj.200156

"Patients with mental health concerns across the country know all too well that it is challenging to receive needed care, and they desire better access to care," writes Dr. David Gratzer, Centre for Addiction and Mental Health and the University of Toronto.

"There is no single solution to address the care gap that people with mental distress face in Canada. But by looking to international examples, exploring innovative approaches and making better use of existing resources, barriers to access are more likely to be successfully overcome," he writes.

Read a related article by research coauthor Dr. Paul Kurdyak, Physician-based availability of psychotherapy in Ontario: a population-based retrospective cohort study in CMAJ Open: http://cmajopen.ca/content/8/1/E105.full

"Temporal trends in objectively measured and perceived mental health and use of mental health services: a population-based study in Ontario, 2002-2014" is published March 30, 2020.

The brain is one of our most vulnerable organs, as soft as the softest tofu. Brain implants, on the other hand, are typically made from metal and other rigid materials that over time can cause inflammation and the buildup of scar tissue.

MIT engineers are working on developing soft, flexible neural implants that can gently conform to the brain's contours and monitor activity over longer periods, without aggravating surrounding tissue. Such flexible electronics could be softer alternatives to existing metal-based electrodes designed to monitor brain activity, and may also be useful in brain implants that stimulate neural regions to ease symptoms of epilepsy, Parkinson's disease, and severe depression.

Led by Xuanhe Zhao, a professor of mechanical engineering and of civil and environmental engineering, the research team has now developed a way to 3D print neural probes and other electronic devices that are as soft and flexible as rubber.

The devices are made from a type of polymer, or soft plastic, that is electrically conductive. The team transformed this normally liquid-like conducting polymer solution into a substance more like viscous toothpaste -- which they could then feed through a conventional 3D printer to make stable, electrically conductive patterns.

The team printed several soft electronic devices, including a small, rubbery electrode, which they implanted in the brain of a mouse. As the mouse moved freely in a controlled environment, the neural probe was able to pick up on the activity from a single neuron. Monitoring this activity can give scientists a higher-resolution picture of the brain's activity, and can help in tailoring therapies and long-term brain implants for a variety of neurological disorders.

"We hope by demonstrating this proof of concept, people can use this technology to make different devices, quickly," says Hyunwoo Yuk, a graduate student in Zhao's group at MIT. "They can change the design, run the printing code, and generate a new design in 30 minutes. Hopefully this will streamline the development of neural interfaces, fully made of soft materials."

Yuk and Zhao have published their results in the journal Nature Communications. Their co-authors include Baoyang Lu and Jingkun Xu of the Jiangxi Science and Technology Normal University, along with Shen Lin and Jianhong Luo of Zheijiang University's School of Medicine.

From soap water to toothpaste

Conducting polymers are a class of materials that scientists have eagerly explored in recent years for their unique combination of plastic-like flexibility and metal-like electrical conductivity. Conducting polymers are used commercially as antistatic coatings, as they can effectively carry away any electrostatic charges that build up on electronics and other static-prone surfaces.

"These polymer solutions are easy to spray on electrical devices like touchscreens," Yuk says. "But the liquid form is mostly for homogenous coatings, and it's difficult to use this for any two-dimensional, high-resolution patterning. In 3D, it's impossible."

Yuk and his colleagues reasoned that if they could develop a printable conducting polymer, they could then use the material to print a host of soft, intricately patterned electronic devices, such as flexible circuits, and single-neuron electrodes.

In their new study, the team report modifying poly (3,4-ethylenedioxythiophene) polystyrene sulfonate, or PEDOT:PSS, a conducting polymer typically supplied in the form of an inky, dark-blue liquid. The liquid is a mixture of water and nanofibers of PEDOT:PSS. The liquid gets its conductivity from these nanofibers, which, when they come in contact, act as a sort of tunnel through which any electrical charge can flow.

If the researchers were to feed this polymer into a 3D printer in its liquid form, it would simply bleed across the underlying surface. So the team looked for a way to thicken the polymer while retaining the material's inherent electrical conductivity.

They first freeze-dried the material, removing the liquid and leaving behind a dry matrix, or sponge, of nanofibers. Left alone, these nanofibers would become brittle and crack. So the researchers then remixed the nanofibers with a solution of water and an organic solvent, which they had previously developed, to form a hydrogel -- a water-based, rubbery material embedded with nanofibers.

They made hydrogels with various concentrations of nanofibers, and found that a range between 5 to 8 percent by weight of nanofibers produced a toothpaste-like material that was both electrically conductive and suitable for feeding into a 3D printer.

"Initially, it's like soap water," Zhao says. "We condense the nanofibers and make it viscous like toothpaste, so we can squeeze it out as a thick, printable liquid."

Implants on demand

The researchers fed the new conducting polymer into a conventional 3D printer and found they could produce intricate patterns that remained stable and electrically conductive.

As a proof of concept, they printed a small, rubbery electrode, about the size of a piece of confetti. The electrode consists of a layer of flexible, transparent polymer, over which they then printed the conducting polymer, in thin, parallel lines that converged at a tip, measuring about 10 microns wide -- small enough to pick up electrical signals from a single neuron.

The team implanted the electrode in the brain of a mouse and found it could pick up electrical signals from a single neuron.

"Traditionally, electrodes are rigid metal wires, and once there are vibrations, these metal electrodes could damage tissue," Zhao says. "We've shown now that you could insert a gel probe instead of a needle."

In principle, such soft, hydrogel-based electrodes might even be more sensitive than conventional metal electrodes. That's because most metal electrodes conduct electricity in the form of electrons, whereas neurons in the brain produce electrical signals in the form of ions. Any ionic current produced by the brain needs to be converted into an electrical signal that a metal electrode can register -- a conversion that can result in some part of the signal getting lost in translation. What's more, ions can only interact with a metal electrode at its surface, which can limit the concentration of ions that the electrode can detect at any given time.

In contrast, the team's soft electrode is made from electron-conducting nanofibers, embedded in a hydrogel -- a water-based material that ions can freely pass through.

"The beauty of a conducting polymer hydrogel is, on top of its soft mechanical properties, it is made of hydrogel, which is ionically conductive, and also a porous sponge of nanofibers, which the ions can flow in and out of," Lu says. "Because the electrode's whole volume is active, its sensitivity is enhanced."

In addition to the neural probe, the team also fabricated a multielectrode array -- a small, Post-it-sized square of plastic, printed with very thin electrodes, over which the researchers also printed a round plastic well. Neuroscientists typically fill the wells of such arrays with cultured neurons, and can study their activity through the signals that are detected by the device's underlying electrodes.

For this demonstration, the group showed they could replicate the complex designs of such arrays using 3D printing, versus traditional lithography techniques, which
involve carefully etching metals, such as gold, into prescribed patterns, or masks -- a process that can take days to complete a single device.

"We make the same geometry and resolution of this device using 3D printing, in less than an hour," Yuk says. "This process may replace or supplement lithography techniques, as a simpler and cheaper way to make a variety of neurological devices, on demand."

Fiber optic cables, it turns out, can be incredibly useful scientific sensors. Researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) have studied them for use in carbon sequestration, groundwater mapping, earthquake detection, and monitoring of Arctic permafrost thaw. Now they have been awarded new grants to develop fiber optics for two novel uses: monitoring offshore wind operations and underground natural gas storage.

"A fiber cable has a glass core that allows you to send an optical signal down at the speed of light; when there is any vibration, strains, or stresses or changes in temperature of the material that is being monitored, that information will be carried in the light signal that is scattered back," said Berkeley Lab scientist Yuxin Wu, who is leading both projects.

The California Energy Commission has awarded Berkeley Lab $2 million for the offshore wind project and $1.5 million for the natural gas project. Both projects are in collaboration with UC Berkeley, and for the natural gas project, Berkeley Lab will also collaborate with PG&E, Schlumberger, and C-FER Technologies (a Canadian company), to carry out the tests.

From gearbox failure to humpback whale movements

Europe is at the forefront of offshore wind development. Other parts of the world are only in the early stages of commercialization, but it is growing quickly, including in the U.S., where the Department of Energy (DOE) has been supporting development of the technology. Offshore wind resources in the U.S. are abundant and have the potential to provide nearly double the total amount of electricity currently generated in the U.S., according to a 2016 DOE report.

One of the advantages of offshore wind for the U.S. is that the resource is close to dense coastal populations. Therefore, energy transmission is a lesser challenge compared to other renewable energy sources such as onshore wind and solar farms, which are typically located farther away from population centers due to the availability and cost of real estate.

Off the California coast, the ocean floor drops off steeply, making floating wind turbines - which are tethered to the ocean floor by mooring chains, unlike conventional "fixed bottom" offshore wind turbines - the only viable option. But this technology faces several obstacles, including how to do maintenance and operations on remote installations in the ocean economically and how to monitor if hazards such as earthquakes or extreme weather conditions disrupt operations.

This is where the fiber optic cables come in.

"One of the most expensive components of a wind turbine is the gearbox; they also tend to be the part that's most vulnerable to failure," said Wu, who is also head of Berkeley Lab's Geophysics Department. "Often before they fail they produce abnormal vibrations or excessive heat due to increased or irregular friction. We intend to use fiber optic cables to monitor the vibrational, strain, and temperature signal of the gearbox, in order to pinpoint where problems are happening."

Wrapping fiber optic cables around the entire gearbox can provide a 3D map of changes with resolution at the millimeter scale. "It could help identify problems with the gearbox at an early stage, which would trigger emergency management, before a catastrophic failure causing loss of the whole turbine," Wu said.

What's more, Wu said the project intends to explore how the fiber optic cables can be used to detect marine mammal activity. The sensitivity of the fiber signal could allow for differentiation between, say, crashing waves and a pod of whales swimming by.

"Environmentally sustainable development of offshore wind is critical," he said. "With a large offshore wind farm, there would be many of these mooring lines securing the turbine structures to the ocean floor. If a humpback whale swims by, what are the impacts of these mooring lines on their activities? Will the whales generate unique vibrational signals that can be picked up by the fiber optic sensors? If we can track the signals of a whale swimming by, it will allow us to evaluate whether and how the offshore wind turbine impacts marine mammals."

Wu added that he is looking to learn more about whales and other marine mammals from marine biologists and also seeking a partner to collaborate with to test the sensors in the ocean.

Making underground gas reservoirs safer

Similarly, Wu and his research partners hope to use fiber optic cables to monitor the boreholes of underground natural gas storage reservoirs. The borehole is used to inject and withdraw gas from vast underground storage reservoirs. Like any pipe, these boreholes degrade and corrode over time. The massive gas leak at Aliso Canyon in 2016, in which thousands of families had to evacuate their homes, was concluded to be caused by corrosion damage of the borehole.

Thus, borehole integrity is of paramount importance to safe storage of natural gas in the subsurface. It is currently monitored mostly using tools that are intrusive, expensive, and incapable of providing frequent, real-time data. "It is difficult to predict borehole degradation trajectory with the sparse data generated by traditional methods. Having higher frequency datasets covering the entire borehole is key to provide an early warning of potential borehole failures," Wu said.

In the new CEC-funded project, Berkeley Lab will work with UC Berkeley, PG&E, Schlumberger, and C-FER to test a novel suite of technologies for autonomous real-time monitoring using two methods, one based on distributed strain, vibration, and temperature sensing in fiber optic cables and the other using electromagnetic wave reflectometry.

EM-TDR (or electromagnetic time domain reflectometry) is similar to the fiber optic technology except that it uses longer wavelength electromagnetic waves instead of visible light (also an electromagnetic wave but at much short wavelength) as signals. "EM-TDR sends electromagnetic waves into an electronically conductive material, and when there is a change due to damage, such as corrosion, you get an EM signal back which can help you identify corrosion or other degradations," Wu said.

And because the borehole is made of steel, which is electrically conductive, no downhole equipment will need to be installed. Thus, EM-TDR is very easy to deploy and can be used under many circumstances that prevent the use of other types of sensors. On the other hand, EM-TDR is still an early-stage technology; this new project will allow further testing and development.

For both the offshore wind and natural gas projects, the scientific challenge, Wu said, is optimizing the technology design and sensitivity and developing real-time edge computing technologies. "In addition to using commercial systems, our team is developing new fiber interrogators that will allow us to not only get to the original raw data but also play with the physics to better design a system that can give us the most sensitive signal we want," he said. "In addition, we will be developing machine learning-based edge computing methods to turn raw data into actionable intelligence quickly. This is key for real-time monitoring."

Globally, there is a growing concern regarding the presence of trace emerging contaminants such as retinoids and oestrogenic endocrine disrupting chemicals (EDCs) in aquatic environments. Retinoids such as retinoic acids and their metabolites, which are the derivatives of vitamin A, can cause abnormal morphological development in amphibians, fish, and snails at elevated levels. Oestrogenic EDCs like alkylphenols and bisphenol A are environmental oestrogens that can induce feminization of male fish and abnormal development in aquatic organisms.

Sewage effluents are a significant source for the continuous input of these contaminants into the aquatic environment. High levels of these chemical contaminants are commonly found in sewage effluents discharged from conventional sewage treatment plants (STPs).

An interdisciplinary team led by the University of Hong Kong (HKU) has developed a novel wastewater treatment system that can effectively remove conventional pollutants, and recover valuable resources such as phosphorus and organic materials (i.e., carbon fibres and volatile organic acids).

This novel system combines chemically enhanced primary sedimentation (CEPS) of sewage with acidogenic fermentation of sludge in tandem (Image 1). A series of laboratory experiments were conducted to prove that this novel system can effectively remove trace emerging chemical contaminants from wastewater and is more cost effective compared with conventional wastewater treatment systems.

The results of this study have been recently published in Water Research and Environment International.

Moreover, in collaboration with the Nanshan Sewage Treatment Plant in Shenzhen, a pilot wastewater treatment system (Image 2) adopting the novel treatment process has been under construction in Shenzhen since 2019. It will come into operation and testing by this summer if the COVID-19 outbreak subsides.

Background

In the past few years, Professor Xiao-Yan Li of the Department of Civil Engineering who led the interdisciplinary research project, has been collaborating with Professor Kenneth Leung from HKU School of Biological Sciences and the Swire Institute of Marine Science to examine the levels and removal efficiencies of retinoids and oestrogenic EDCs from wastewater by the novel wastewater treatment process developed by the research team, and to compare that with the conventional STPs.

The research team first examined the levels and removal efficiencies of retinoids and oestrogenic EDCs in Shatin, Stanley and Stonecutters Island STPs in Hong Kong by collecting wastewater and sludge samples from different stages of the treatment process, and analyzing the samples for retinoids and oestrogenic EDCs using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Secondly, a series of laboratory experiments were conducted using a small-scale pilot plant of the novel wastewater treatment process. Samples of wastewater and sludge were taken for the chemical analysis using the protocols developed by Professor Leung's team.

Key Findings

The results indicated that the three STPs can only remove an average of 57% of retinoids (range: 41-82%) and an average of 54% of oestrogenic EDCs (range: 31-79%) from wastewater influents (this work was published in Environment International).

Using the novel treatment system operated under laboratory conditions, the CEPS process alone was demonstrated to be 16 - 19% more effective in removing retinoids and EDCs than the conventional STPs. 65 - 80% of retinoids and 72 - 73% of EDCs can be removed from the CEPS process (Image 3).

After acidogenic fermentation of the CEPS sludge, 50 - 58% of retinoids and 47 - 50% of EDCs were further removed from the supernatants of sludge (this work has been recently published in Water Research).

Compared to the conventional STPs, the novel treatment system integrating CEPS with acidogenic fermentation of sludge is comparatively more efficient in removing emerging chemical contaminants from wastewater, and hence could reduce their environmental impacts.

In terms of cost effectiveness, the CEPS process has been shown, by other studies, to be more cost-effective than the conventional wastewater treatment process. For instance, the cost of CEPS for wastewater treatment is less than a half of that of the secondary wastewater treatment (i.e., activated sludge process). On one hand, acidogenic fermentation of CEPS sludge can further reduce the treatment cost by recovering organic carbon and phosphate resources from the sludge as the harvested organic carbon and phosphate can be utilized to produce carbon fibers and fertilizers respectively. On the other hand, the acidogenic fermentation of CEPS sludge can provide additional removal of pollutants. The novel treatment process, therefore, offers win-win outcomes.

The Way Forward

Professor Li, who led the study, said: "When the pilot wastewater treatment system in Shenzhen comes into operation and testing, we hope to demonstrate that this innovative technology will use less energy, generate cleaner effluent and recover more useful materials from the sludge."

Professor Leung said, "We are very pleased to gather evidence for supporting our hypothesis that our novel sewage treatment system can effectively remove the emerging chemical contaminants. With the scaled-up pilot plant in Shenzhen, we will further investigate the removal efficiency of other classes of common pollutants by this novel treatment system."

Regarding its potential application in Hong Kong, Professor Li added, "Our system can be easily retrofitted onto the existing STPs in Hong Kong, like add-on units. For instance, the pilot system will be connected to the existing Nanshan STP in Shenzhen to test its performance. If successful, this will pave the way for advancing wastewater treatment in China and beyond."

Medical product recalls number in the thousands each year. In the first quarter of 2018, for example, 84 pharmaceutical companies in the U.S. reported at least one recall. Some 4,500 Food and Drug Administration-approved drugs and devices are pulled from shelves annually -- decisions greatly influenced by the presence of women on a firm's board, according to new research from the University of Notre Dame.

Severe product problems that injure or kill consumers are recalled much faster when there are women on the board, and lower-severity product defects that can be hidden from regulators and not recalled are less often hidden when there are female directors, according to "The Influence of Female Directors on Product Recall Decisions," forthcoming at Manufacturing & Service Operations Management from lead author Kaitlin Wowak, assistant professor of information technology, analytics and operations in Notre Dame's Mendoza College of Business.

Wowak, along with co-authors George Ball at Indiana University, Corinne Post at Lehigh University and David Ketchen at Auburn University, found that compared to boards composed of all male directors, those with female members announce high-severity recalls 28 days faster, a 35 percent reduction in recall timing -- truly a matter of life or death, according to Wowak.

The researchers analyzed 4,271 medical product recalls from 2002 to 2013 across 92 publicly traded firms regulated by the FDA.

Additionally, they found the more women on the board, the more efficient recalls become. While consumers have the most to gain from faster recalls of defective products, Wowak notes, firms have the most to lose since recalls expose them to the most public, regulatory and stock market penalties. As such, the study shows high-risk decisions require more female input to push firms to act faster.

"Just one female director is insufficient to push firms to recall these serious problems more quickly," Wowak explains. "It takes at least two female directors to influence the timeliness of severe product recalls, and three moves things along even faster."

However, in instances involving low-severity recalls that could be hidden from regulators, even having one women at the boardroom table makes a difference. Firms with female directors announce 120 percent more low-severity, high-discretion recalls than firms with all-male boards.

"In this case, just one female director can influence how these decisions are made," Wowak says, "and the number of low-severity recalls announced continues to increase as firms add each additional female director."

"We believe our study shows that there is a difference in very real and important outcomes between firms who add women to their boards and those who don't," she says. "More broadly, we align with recent calls for all directors on boards to look beyond the bottom line and be more responsive to all stakeholders, especially when products may harm or kill their customers or other stakeholders."

Timely detection and accurate segmentation of acute ischemic stroke (AIS) lesions on magnetic resonance images (MRIs) are essential for the triaging patient for endovascular therapy. Lesion segmentation is a routine process where the abnormal areas within brain images are qualitatively and manually picked by expert radiologists. However, manual lesion segmentation is time consuming and suffers from operator-bias. Accordingly, efficient and low-cost approaches for AIS lesion screening are yet to be introduced.

This research introduces a novel and fully automated technique for detection and segmentation of AIS lesions on MRIs and classification of images into stroke and none-stroke. This fully automated anomaly-detection method compares diffusion weighted images (DWIs) and apparent diffusion coefficients (ADC) images of the subjects with a group of healthy images in voxel-level. Areas with hyperintensity on DWI and hypointensity on ADC are identified as lesions and saved as lesion masks. The lesion segmentation method was investigated on approximately 100 cases. Since there is a risk of false lesion identification due to the artifacts, noises, and image low resolution, the lesion masks created by the method are screened and filtered via a binary classifier which either confirms that the created lesion mask contains a real AIS lesion or not. The classification performance was evaluated on about 200 MRIs.

The published results in the Journal of Neuroscience Methods show good agreement with the manually drawn lesions by experts (gold standard). The whole approach, including lesion segmentation and image classification, is straightforward, fast and does not require high computation power and memory.

"We believe that this method has the capacity to be implemented on an ordinary desktop workstation integrated into the routine clinical diagnostic pipelines of the hospitals. This approach can help the radiologists to speed up the workflow of lesion detection and to reduce the operator bias in lesion segmentation owing to the reproducibility of the method", tells project researcher Sanaz Nazari-Farsani from Turku PET Centre.

Below please find link(s) to new coronavirus-related content published today in Annals of Internal Medicine. All coronavirus-related content published in Annals of Internal Medicine is free to the public. A complete collection is available at https://annals.org/aim/pages/coronavirus-content.

COVID-19 found in sputum and feces samples after pharyngeal specimens no longer positive

Clinicians from the Institute of Infectious Diseases at Beijing Ditan Hospital, Capital Medical University found that some patients had positive real-time fluorescence polymerase chain reaction (RT-PCR) test results for SARS-CoV-2 in the sputum or feces after the pharyngeal swabs became negative. Pharyngeal swabs are widely used to determine the appropriateness for a patient's discharge from the hospital and/or whether isolation continues to be required. These findings raise concerns over whether patients with negative pharyngeal swabs are truly virus-free or if sampling of additional body sites might be needed.

The clinicians retrospectively identified a convenience sample of patients admitted to Beijing Ditan Hospital, Capital Medical University with a diagnosis of COVID-19 and paired RT-PCR testing of pharyngeal swabs with either sputum or feces. Among 133 patients admitted with COVID-19 from January 20 to February 27, 2020, the authors identified 22 with an initial or follow-up positive sputum or fecal samples paired with a follow-up negative pharyngeal sample. RT-PCR positive for SARS-CoV2 of sputum and feces was seen up to 39 and 13 days, respectively, after the obtained pharyngeal samples were negative.

The researchers caution that the study was not carried out in a systematic fashion with sampling of all patients in a protocolized manner, and it is not known whether these positive sputum or fecal results indicate that the patient could still be infectious to others. However, their findings are potentially important because they suggest that more study is needed in this area. The full report, published in Annals of Internal Medicine, is available for free at http://annals.org/aim/article/doi/10.7326/M20-0991.

Media contact: To speak with lead authors Fujie Zhang, MD, PhD or Hui Zeng, MD, PhD please contact Fujie Zhang, MD, PhD directly at treatment@chinaaids.cn.

If you see people walking down a street and coming to a junction, it's difficult to predict which direction they might take. But, if you see people sitting in separate boats, floating down a stream, and the stream splits into two channels, it's likely that most, if not all, of them will be carried down one channel, the channel that has the stronger flow.

Scientists in the Quantum Dynamics Unit at Okinawa Institute of Science and Technology Graduate University (OIST) are looking at something similar, but their research is at a much smaller scale. They're running experiments to see how the motion of electrons is impacted by fluid. This study was published in Physical Review Letters.

Professor Denis Konstantinov, who runs the Unit, demonstrated the concept with a piece of wire. "If we run an electric current through a piece of wire, then we know that the electrons will move from one end to the other. If we split the wire into two, half of electrons will flow down one side, and the other half will flow down the other."

This is due to Ohm's law, a physics law, which states that electric current is proportional to voltage and inversely proportional to resistance, so if the resistance equally distributes between two channels, half the electrons will go down each channel.

"But," Professor Konstantinov explained. "If the electrons are sitting on liquid, rather than in a solid, they might break Ohm's law. That's what we wanted to measure."

This theory comes from the concept of a polaron, which is an electron that's "dressed" by a cloud of the medium it's sitting in. This makes it heavier, slower and changes its behavior. Previously polarons have been discussed in terms of ionic crystals in solids, but much more rarely in liquids.

The researchers used superfluid helium, which has several unique properties. For example, it remains in a liquid form at temperatures down to absolute zero, when any other liquid would freeze, and behaves like fluid with zero viscosity, or no resistance. Electrons would only be able to sit on top, rather than sinking. Thus, it provided the researchers with a 2D electron system.

They created a tiny structure, on the scale of micrometers, of three reservoirs connected by a T-junction, and slightly submerged this structure in superfluid helium.

As the electrons moved and disturbed the liquid, they created capillary waves, or ripples. At high electron densities, the electrons became trapped in the shallow dimple of the waves. These are slightly different from the traditional polarons, so the researchers called them ripplopolarons, inspired by their similarities to ripples on water.

"Ohm's law states that the electrons should split at the T junction," said Professor Konstantinov, "But, due to momentum conservation, the flow of fluid should keep going down the straight path. We theorized that the ripplopolarons - the trapped electrons - would break Ohm's law and all be carried in the same direction."

The researchers applied an electric field, which moved the ripplopolarons out of the left reservoir. As they moved along the channel, they came to the junction, and could either turn and go to the side reservoir or continue straight to the right reservoir.

It was as the researchers predicted. The ripplopolarons continued straight from the left reservoir to the right reservoir, following momentum conservation rather than Ohm's law.

However, this law-breaking behavior only occurred in certain situations. The density of electrons had to be high, or the ripplopolarons wouldn't form, and the temperature had to be low, or the waves would simply pitter out. When the researchers ran the experiment in the opposite direction, they found the same unidirectional movement, but when they ran the electrons out of the side reservoir, they found that the ripplopolarons would crash into the wall at the top, the waves would disappear and the [now-free] electrons would once again follow Ohm's law.

Although there are applications for understanding how electrons operate, this experiment was mainly driven by curiosity. "We wanted to know how electrons are influenced by the medium they're in," said Professor Konstantinov, "For us, it was the discovery that was exciting. But it's also important that we understand these properties. Electrons in fluids could be useful when it comes to building qubits, the tiny parts that make up quantum computers. If we could use electrons in fluids for qubits, we could create a flexible, moveable architecture for the computers."