Tech

Researchers from China, France and the USA have evaluated China's success in stemming emissions from its coal-fired power plants (CPPs).

CPPs are one of the main contributors to air pollution in China, and their proliferation over the last 20 years has had significant impacts on air quality and public health.

These impacts led authorities to introduce measures to control emissions from CPPs and reduce their effects.

Writing today in Environmental Research Letters, researchers examined if these policies have been effective, and measured their benefits.

Dr Qiang Zhang, from Tsinghua University, China, is the study's lead author. He said: "Between 2005 and 2015, the coal-fired power generation of CPPs in China grew by more than 97 percent. In 2010, CPPs' sulphur dioxide, nitrogen oxide and fine particulate matter (PM2.5) emissions accounted for 33 per cent, 33 per cent and 6 percent of China's total national emissions, respectively. The large amount of air pollutant emissions from CPPs causes fine particulate air pollution, which contributed 26 percent of the fine particulate nitrate and 22 percent of the fine particulate sulphate ambient concentration in 2012.

"To combat this, China introduced three primary policies for CPPs during 2005-2020. They aimed to improve efficiency energy by promoting large CPPs and decommissioning small plants during 2005-2020; brought in national emission cap requirements by installing of end-of-pipe control devices during 2005-2015; and introduced ultra-low emission standards between 2014-2020."

To measure the effect these policies had on emissions, the team developed two retrospective emission scenarios based on a high-resolution coal-fired power plant database for China.

They also developed two emission prediction scenarios to forecast the CPPs' emission changes associated with the implementation of ultra-low emission standards and power generation increments during 2015-2020.

Finally, they evaluated the air quality and health impacts associated with CPPs' emission changes during 2005-2020, using a regional air quality model and the integrated exposure-response model.

Dr Fei Liu, from the Universities Space Research Association, Goddard Earth Sciences Technology and Research, USA, is the study's corresponding author. She said: "Our results show that overall, China's efforts on emission reductions, air quality improvement and human health protection from CPPS between 2005-2020 were effective.

"We found that the upgrading of end-pipe control facilities could reduce PM2.5 exposures by 7.9 ug/m3 and avoid 111,900 premature deaths annually. Meanwhile, the early retirement of small and low-efficiency units could reduce PM2.5 exposures by 2.1 ug/m3 and avoid 31,400 annual premature deaths.

"This suggests similar measures could be taken in countries such as India, to enable the reduction of emissions alongside rapid economic development."

New research from Cass Business School has found that battery icons on mobile phones shape how people view time and space, and how battery conservation practices define user identities.

The study of London commuters found that respondents viewed their daily trip in terms of the time and distance between charging points for mobile technology.

"People no longer think about their destination being 10 km away or 10 stops on the tube. They think about it being 50 per cent of their battery away," said the study's lead author, Dr Thomas Robinson.

"During interviews respondents discussed how a full battery gauge made them feel positive and as though they could go anywhere or do anything. Anything less than half full, however, induced feelings of profound anxiety and discomfort," he said.

One of the study's respondents described the experience of watching their battery icon throughout the day: "Full would be 'Yeah, ok great', good to go for the day'; 50 per cent I'd be a bit 'Oh God, I had better stop it from updating itself all the time in the background' ... then it would be at 30 per cent and I would be like: 'Now I'm not having fun anymore'," the respondent said.

As mobile phones are now far more than just means of communication -- they are maps, digital wallets, entertainment systems, diaries, banking, step and pulse counters etcetera -- battery icons are at the heart of social and consumer tasks.

Devices defining identity

Management of battery levels structures people's daily activities -- from arguing over who can charge their device next to the bed, to making decisions about where to go shopping in order to access complementary charge stations.

The study found that this reliance means people now identify themselves and others in relation to how they maintain their battery levels.

Respondents who monitor their battery gauges and take measures to keep a high level of charge identify themselves as "control freaks", "quite anal", "planners" and "a bit OCD".

People who regularly allow their phone batteries to run out of charge were identified as "frightfully frustrating", "disorganised" and "inconsiderate".

"We found that people who let their phones batteries run out are viewed by others as out of touch with the social norm of being connected and therefore unable to be competent members of society," Dr Robinson said.

"Phones have become such a nexus for everything that we are that an inability to effectively manage battery life becomes symbolic of an inability to manage life."

The paper Portable Technology and Multi-Domain Energy Consumption is scheduled for publication in the journal Marketing Theory.

Highlights

There has been a substantial increase in the number of transplants using HCV-infected kidneys across the United States.

Since September 2018, most HCV-infected kidneys were transplanted into patients without the infection.

HCV-infected kidneys function just as well as uninfected kidneys throughout the year after transplantation.

Washington, DC (September 12, 2019) -- A recent analysis reveals that kidneys from donors infected with hepatitis C virus (HCV) are now routinely used in transplants at many U.S. centers, and they are functioning well one year after transplantation. The findings, which appear in an upcoming issue of JASN, are reassuring that the use of these organs is safe and effective in the near-term.

There are more than 2 million adults in the United States with HCV infection, and due to the opioid epidemic, there has been a large increase in the number of young organ donors who have become infected. Prior to 2015, many kidneys from donors with HCV were discarded, but since then, studies have shown that physicians can successfully transplant these kidneys and treat the infection with antiviral medications after transplantation.

Questions have remained, however. First, because HCV can damage the kidneys, it was not clear whether HCV-infected kidneys have a comparable function to similar uninfected kidneys. Second, it was unknown if the promising results of earlier studies would be confirmed in a larger study that included patients from across the United States.

To investigate, Vishnu S. Potluri, MD, MPH, David S. Goldberg, MD, MSCE and Peter P. Reese, MD, MSCE (University of Pennsylvania) and their colleagues analyzed 2015-2019 national transplant registry data on the use of HCV-infected kidneys. They also compared outcomes for HCV-infected kidneys to similar quality HCV-uninfected kidneys.

The researchers found that there has been a substantial increase in the number of transplants using HCV-infected kidneys across the United States. There also has been a change in the use of HCV-infected kidneys: until September 2018, most HCV-infected kidneys were transplanted into patients with pre-existing HCV, but since September 2018, the majority of HCV-infected kidneys were transplanted into patients without the infection. The team also found that HCV-infected kidneys function just as well as uninfected kidneys throughout the first year after transplantation.

"Our study showed that transplants with HCV- infected kidneys are now routinely performed at many centers, and they are functioning well at one year after transplant," said Dr. Reese. The authors noted that the findings provide strong evidence that HCV-infected kidneys are a valuable resource for transplantation, and that disincentives for accepting these organs should be addressed. In the future, it may also be harder for patients with pre-existing HCV infection to get access to these HCV-infected organs for transplantation. "These findings represent a small, but important victory, in the effort to make every organ donation count," added Dr. Potluri.

Topological insulators are a game-changing class of materials; charged particles can flow freely on their edges and route themselves around defects, but can't pass through their interiors. This perfect surface conduction holds promise for fast and efficient electronic circuits, though engineers must contend with the fact that the interiors of such materials are effectively wasted space.

Now, researchers from the University of Pennsylvania, where topological insulators were first discovered in 2005, have shown a way to fulfill that promise in a field where physical space is at an even bigger premium: photonics. They have shown, for the first time, a way for a topological insulator to make use of its entire footprint.

By using photons instead of electrons, photonic chips promise even faster data transfer speeds and information-dense applications, but the components necessary for building them remain considerably larger than their electronic counterparts, due to the lack of efficient data-routing architecture.

A photonic topological insulator with edges that can be redefined on the fly, however, would help solve the footprint problem. Being able to route these "roads" around one another as needed means the entire interior bulk could be used to efficiently build data links.

Researchers at Penn's School of Engineering and Applied Science have built and tested such a device for the first time, publishing their findings in the journal Science.

"This could have a big impact on large-information capacity applications, like 5G, or even 6G, cellphone networks," says Liang Feng, assistant professor in Penn Engineering's Departments of Materials Science and Engineering and Electrical and Systems Engineering.

"We think this may be the first practical application of topological insulators," he says.

Feng led the study along with graduate student Han Zhao, a member of his lab. Fellow lab members Xingdu Qiao, Tianwei Wu and Bikashkali Midya, along with Stefano Longhi, professor at the Polytechnic University of Milan in Italy, also contributed to the research.

The data centers that form the backbone of communication networks route calls, texts, email attachments and streaming movies to and between millions of cellular devices. But as the amount of data flowing through these data centers increases, so does the need for high-capacity data routing that can keep up with the demand.

Switching from electrons to photons would speed up this process for the upcoming information explosion, but engineers must first design a whole new library of devices for getting those photons from input to output without mixing them up and losing them in the process.

Advances in data-processing speed in electronics have relied on making their core components smaller and smaller, but photonics researchers have needed to take a different approach.

Feng, Zhao and their colleagues set out to maximize the complexity of photonic waveguides -- the prescribed paths individual photons take on their way from input to output -- on a given chip.

The researchers' prototype photonic chip is roughly 250 microns squared, and features a tessellated grid of oval rings. By "pumping" the chip with an external laser, targeted to alter the photonic properties of individual rings, they are able to alter which of those rings constitute the boundaries of a waveguide.

The result is a reconfigurable topological insulator. By changing the pumping patterns, photons headed in different directions can be routed around each other, allowing photons from multiple data packets to travel through the chip simultaneously, like a complicated highway interchange.

"We can define the edges such that photons can go from any input port to any output port, or even to multiple outputs at once," Feng says. "That means the ports-to-footprint ratio is at least two orders of magnitude greater than current state-of-the-art photonic routers and switches."

Increased efficiency and speed is not the only advantage of the researchers' approach.

"Our system is also robust against unexpected defects," Zhao says. "If one of the rings is damaged by a grain of dust, for example, that damage is just making a new set of edges that we can send photons along."

Since the system requires an off-chip laser source to redefine the shape of the waveguides, the researcher's system is not yet small enough to be useful for data centers or other commercial applications. Next steps for the team will be to establish a fast reconfiguring scheme in an integrated fashion.

A simple epidemiological model accurately captures long-term measles transmission dynamics in London, including major perturbations triggered by historical events. Alexander Becker of Princeton University in New Jersey, U.S., and colleagues present these findings in PLOS Computational Biology.

Previous studies have extensively explored how disease outbreaks are affected by variations in demography, such as birth rate, and variations in person-to-person contact, such those arising from school calendars. However, key historical events, such as the 1918 influenza pandemic in London and the World War II evacuation of about 1 million children from London to the countryside, have not been studied in the context of long-term trajectories of disease transmission.

For the new study, Becker and colleagues aimed to mathematically disentangle the disease transmission effects of regular demographic changes, such as variable birth rate, from larger shifts caused by historical events. They took advantage of recent advancements in statistical algorithms to mathematically analyze weekly measles incidence and mortality data reported in London from 1897 to 1991.

The researchers found that a simple mathematical model successfully captured measles transmission dynamics throughout the study period, including the effects of major perturbations caused by historical events. "The most exciting aspect of this research is showing that the London system is able to remain mathematically stable--that is, essentially, well-predicted--in spite of multiple huge perturbations such as the 1918 pandemic and the wartime evacuation," Becker says.

The findings underscore that the long-term dynamics of epidemiological systems can follow simple rules, despite major perturbations. The results could have practical implications for understanding long-term disease dynamics in other contexts, such as the resurgence of measles seen in recent years. They could also help inform understanding of other ecological dynamics, such as predator-prey interactions.

Life on Earth is amazingly diverse, and exhibits striking geographical global patterns in biodiversity. A pair of companion papers published Sept. 13 in Science reveal that mountain regions -- especially those in the tropics -- are hotspots of extraordinary and baffling richness. Although mountain regions cover only 25% of Earth's land area, they are home to more than 85% of the world's species of amphibians, birds, and mammals, and many of these are found only in mountains.

What determines global patterns of biodiversity has been a puzzle for scientists since the days of von Humboldt, Darwin, and Wallace. Yet, despite two centuries of research, this question remains unanswered. The global pattern of mountain biodiversity, and the extraordinarily high richness in tropical mountains in particular, is documented in two companion Science review papers this week. The papers focus on the fact that the high level of biodiversity found on mountains is far beyond what would be expected from prevailing hypotheses.

"The challenge is that, although it is evident that much of the global variation in biodiversity is so clearly driven by the extraordinary richness of tropical mountain regions, it is this very richness that current biodiversity models, based on contemporary climate, cannot explain: mountains are simply too rich in species, and we are falling short of explaining global hotspots of biodiversity," says Professor Carsten Rahbek, lead author of both review papers published in Science.

To confront the question of why mountains are so biologically diverse, scientists at the Center for Macroecology, Evolution and Climate (CMEC) at the GLOBE Institute of the University of Copenhagen work to synthesize understanding and data from the disparate fields of macroecology, evolutionary biology, earth sciences, and geology. The CMEC scientists are joined by individual collaborators from Oxford University, Kew Gardens, and University of Connecticut.

Part of the answer, these studies find, lies in understanding that the climate of rugged tropical mountain regions is fundamentally different in complexity and diversity compared to adjacent lowland regions. Uniquely heterogeneous mountain climates likely play a key role in generating and maintaining high diversity.

"People often think of mountain climates as bleak and harsh," says study co-leader Michael K. Borregaard. "But the most species-rich mountain region in the world, the Northern Andes, captures, for example, roughly half of the world's climate types in a relatively small region--much more than is captured in nearby Amazon, a region that is more than 12 times larger".

Stressing another unique feature of mountain climate, Michael explains, "Tropical mountains, based in fertile and wet equatorial lowlands and extending into climatic conditions superficially similar to those found in the Arctic, span a gradient of annual mean temperatures over just a few km as large as that found over 10,000 km from the tropical lowlands at Equator to the arctic regions at the poles. It's pretty amazing if you think about it".

Another part of the explanation of the high biodiversity of certain mountains is linked to the geological dynamics of mountain building. These geological processes, interacting with complex climate changes through time, provide ample opportunities for evolutionary processes to act.

"The global pattern of biodiversity shows that mountain biodiversity exhibits a visible signature of past evolutionary processes. Mountains, with their uniquely complex environments and geology, have allowed the continued persistence of ancient species deeply rooted in the tree of life, as well as being cradles where new species have arisen at a much higher rate than in lowland areas, even in areas as amazingly biodiverse as the Amazonian rainforest," says Professor Carsten Rahbek.

From ocean crust, volcanism and bedrock to mountain biodiversity

Another explanation of mountain richness, says the study, may lie in the interaction between geology and biology. The scientists report a novel and surprising finding: the high diversity is in most tropical mountains tightly linked to bedrock geology--especially mountain regions with obducted, ancient oceanic crust. To explain this relationship between geology and biodiversity, the scientists propose, as a working hypothesis, that mountains in the tropics with soil originating from oceanic bedrock provide exceptional environmental conditions that drive localized adaptive change in plants. Special adaptations that allow plants to tolerate these unusual soils, in turn, may drive speciation cascades (the speciation of one group leading to speciation in other groups), all the way to animals, and ultimately contribute to the shape of global patterns of biodiversity.

The legacy of von Humboldt - his 250th anniversary

The two papers are part of Science's celebration of Alexander von Humboldt's 250th birth anniversary. In 1799, Alexander von Humboldt set sail on a 5-year, 8000-km voyage of scientific discovery through Latin America. His journey through the Andes Mountains, captured by his famous vegetation zonation figure featuring Mount Chimborazo, canonized the place of mountains in understanding Earth's biodiversity.

Acknowledging von Humboldt's contribution to our understanding of the living world, Professor Carsten Rahbek, one of the founding scientists of the newly established interdisciplinary GLOBE Institute at the University of Copenhagen says:

"Our papers in Science are a testimony to the work of von Humboldt, which truly revolutionized our thinking about the processes that determine the distribution of life. Our work today stands on the shoulders of his work, done centuries ago, and follows his approach of integrating data and knowledge of different scientific disciplines into a more holistic understanding of the natural world. It is our small contribution of respect to the legacy of von Humboldt."

Amid ongoing uncertainty around the value of the Hubble Constant, uncertainty largely created by issues around measuring distances to objects in the galaxy, scientists who used a new distance technique have derived a different Hubble value, one "somewhat higher than the standard value," as Tamara Davis describes it in a related Perspective. She says the techniques involved to reach this estimate are valuable because they can "help establish whether new physics is needed to explain the [Hubble Constant] discrepancy, or whether we should look harder for possible systematic errors in one or more measurements." Since it flashed into existence, the Universe has been expanding at a rate described by the Hubble constant (H0). The value of the H0, however, is the subject of controversy; around the year 2000, astrophysicists had reached the consensus value of about 70 ± 5 km/s/Mpc, but recently, estimates on either side of that value have also been suggested. "[t]his discrepancy is hard to explain by any systematic errors that have been proposed," writes Davis. Astrophysicists are asking if they must invoke new physics to explain the discrepancy, and new, independent measurements of H0 are useful in addressing related questions. Inh Jee and colleagues studied light from distant galaxies that coincidently lie directly behind closer galaxies. The gravitational field of the foreground galaxy distorts the light from the background galaxy, bending it through multiple paths with different lengths. This strong gravitational lensing also causes time delays between the multiple images. Any variation in the brightness of the background source will be visible in some parts of the gravitational lens before others. The measurement of this delay and the properties of the stars within the lensing galaxy can be combined to determine the lensed galaxy's size, which in turn allows for measurement of the angular diameter distance to the lens. Jee et al. applied this technique to measure the angular diameter distance to two gravitational lensing systems and used them as benchmarks to recalibrate an existing measurement of H0, which they report as 82+/-8 km/s/Mpc. Although statistical precision of their measurement is not good enough to resolve the discrepancy over the value of H0, the method offers a new way of attacking the problem. "This method is insensitive to the lensing caused by small masses along the line of sight, thus alleviating one potentially large source of systematic uncertainty," writes Davis.

Netherlands Institute for Neuroscience researchers have overturned the long held view that congenital nystagmus, a condition where eyes make repetitive involuntary movements, is a brain disorder by showing that its cause is actually retinal. Deficits in just a few proteins involved in one of the retina's earliest light-signal processing steps result in the eye sending an erroneous movement signal to the brain rhythmically. Each time the brain receives a movement "pulse" it initiates an eye movement to compensate for the motion signaled. In this way, mutations in just a handful of proteins at the very first steps of vision lead to the oscillating side to side eye movements that characterize many forms of congenital nystagmus. The study appears in PLOS Biology on 12 September.

Electrical oscillations

Almost everyone will have met someone with eyes that seemingly move around of their own accord, often with a repetitive to and fro motion in a rhythmical fashion. In many instances, these people will have congenital nystagmus. Approximately 1 in 500 people have congenital nystagmus, and while they do not perceive a shaky image, their eyesight tends to be poor.

Until now, and despite many decades of research, the underlying mechanism of congenital nystagmus has remained elusive but its location was widely believed to reside in the brain stem as this area controls eye movements. However, a group of scientists from the Netherlands Institute for Neuroscience and the Erasmus MC, together with colleagues from the United States and Japan, suspected that they had to look elsewhere for the source of this disorder. In this study, they show that electrical oscillations in retinal neurons cause congenital nystagmus.

Night blindness

Twenty years ago, Huib Simonsz, a pediatric ophthalmologist at the Sophia Children's Hospital in Rotterdam, discovered a group of patients who presented with different types of congenital night blindness and the same type of congenital nystagmus. "A defect in two proteins causes these types of night blindness. The two faulty proteins sit on either side of the nerve junction, a synapse, connecting the light-sensitive rods to a retinal interneuron. This impairs the signaling between the two cell types, which in turn causes retinal cells downstream from the interneuron to start oscillating," says Maarten Kamermans, group leader at the Netherlands Institute for Neuroscience.

In the dark, these electrical oscillations occur across the retina but each cell is oscillating independent of the others. But when the lights go on, all the cells are re-set and begin to oscillate synchronously. This produces a very strong signal that when sent to the brainstem is interpreted as the visual image moving on the retina's surface. To adjust for this signaled motion, a compensatory eye movement occurs and produces the side to side eye movements associated with congenital nystagmus.

Conclusive evidence

Kamermans and colleagues found that, for mice and patients with congenital night blindness, their retinal cells and their eye movements oscillated at about 7 times a second. While intriguing, this correspondence did not prove that the two phenomena are related. To show that they were, the researchers used various drugs on the retina to stop, slow and increase the rate at which the retinal cell oscillated, which in turn stopped, slowed and sped up the rate of eye movement oscillations. This conclusive evidence shows that the retinal oscillations cause congenital nystagmus.

"This discovery means that targeted searches for treatments are now possible. These treatments should aim to desynchronize or stop the electrical oscillations in the retina", says Kamermans. The next step in the project will be to find out whether other forms of congenital nystagmus also arise from electrical oscillations in the retina.

A woman's bone marrow may determine her ability to start and sustain a pregnancy, report Yale researchers in PLOS Biology. The study shows that when an egg is fertilized, stem cells leave the bone marrow and travel via the bloodstream to the uterus, where they help transform the uterine lining for implantation. If the lining fails to go through this essential transformation, the embryo cannot implant, and the body terminates the pregnancy.

"We have always known that two kind of things were necessary for pregnancy," says Dr. Hugh Taylor, senior author and the Anita O'Keeffe Young Professor of Obstetrics, Gynecology, and Reproductive Sciences at Yale. "You must have ovaries to make eggs, and you must also have a uterus to receive the embryo. But knowing that bone marrow has a significant role is a paradigm shift."

Previous research has indicated that, in small numbers, bone marrow-derived stem cells contribute to the non-immune environment of the non-pregnant uterus, but it's remained unknown if and how stem cells affect a pregnant uterus. In this study, the researchers were able to prove the physiological relevance of stem cells to pregnancy.

"Some of these bone marrow-derived mesenchymal stem cells travel to the uterus and become decidual cells, which are the cells that are essential for the process of implantation and pregnancy maintenance," explains Dr. Reshef Tal, first author of the study and assistant professor of obstetrics, gynecology and reproductive sciences at Yale.

In two mouse models with the Hoxa11 gene defect, which presents in mice as a defective endometrium, the researchers found that a bone marrow transplant from a healthy donor could improve fertility by promoting sufficient decidualization of the endometrium. In mice with only one copy of the defective gene, the transplant saved pregnancies that would otherwise have been lost and increased litter sizes, while in the mice with two bad copies of the gene, which were thus entirely infertile, the transplant caused growth and repair of the defective endometria.

This study was made possible by a methods breakthrough that Tal and Taylor made a few years ago. For more than two decades, Taylor and his team had been trying to restore fertility in mice with these genetic mutations, but until recently, they didn't have a form of chemotherapy strong enough to allow an effective bone marrow transplant without killing all the eggs of the mice. (Before a bone marrow transplant, chemotherapy or radiation is used to clear the body of the existing bone marrow, so that the donor bone marrow can take its place.)

"We used an anti-metabolite drug, which is still considered a chemotherapy, but it doesn't harm the ovary, and therefore the mice are still able to get pregnant, allowing us to track the transplanted bone marrow cells and investigate their role in reproduction," says Tal. "We are currently translating these findings into humans to better understand the role that these bone marrow-derived stem cells play in recurrent implantation failure and recurrent pregnancy loss, two conditions that are unexplained in the majority of women and have no effective treatment."

Though more research is needed prior to clinical trials, Tal and Taylor see hope for the patients they treat for infertility on the clinical side of their practice in this latest advance.

"These are frustrating medical conditions," says Taylor. "When you have a damaged endometrium leading to infertility or repeated pregnancy loss, all too frequently we have not been able to correct it. Bone marrow can be considered another critical reproductive organ. This finding opens up a new potential avenue for treatment of a condition that has been untreatable in the past."

BUFFALO, N.Y. -- Human hands are remarkably skilled at manipulating a range of objects. We can pick up an egg or a strawberry without smashing it. We can hammer a nail.

One characteristic that allows us to perform a variety of tasks is the ability to alter the firmness of our grip, and University at Buffalo engineers have developed a two-fingered robotic hand that shares this trait.

The design of the robotic hand enables it to absorb energy from impacts during collisions. This prevents whatever the robot is holding from breaking, and also makes it safer for people to work with and near the machines.

Such grippers would be a valuable asset for human-robot partnership in assembly lines in the automotive, electronic packaging and other industries, says Ehsan Esfahani, PhD, associate professor of mechanical and aerospace engineering in the UB School of Engineering and Applied Sciences.

"Our robotic gripper mimics the human hand's ability to adjust the stiffness of the grip. These grippers are designed for collaborative robots that work together with people," Esfahani says. "They're going to be helpers, so they need to be safe, and variable stiffness grippers help to achieve that goal."

VIDEO: https://www.youtube.com/watch?v=O1hRgG55DY4

PHOTOS AND GIF: http://www.buffalo.edu/news/releases/2019/002/017.html

A new study published online on Sept. 10 in IEEE Transactions on Industrial Electronics highlights the device's safe design, including through experiments showing how the gripper's shock-absorbing features keep a spaghetti stick from breaking during a collision.

Magnets give this robot a soft touch

Esfahani explains that magnets are the secret behind the robotic gripper's versatility.

Instead of having two fingers that are fixed in place, each of the gripper's fingers has a magnetic base that sits between two neodymium magnets that repulse, or push against, the finger.

The air gap between the magnets acts like a spring, creating a little give when the hand picks up an object or collides with an external force. The stiffness of the grip can also be adjusted by increasing or decreasing the space between magnets.

In the new paper, Esfahani and Amirhossein Memar, a former UB PhD candidate in mechanical and aerospace engineering, report on these safety features.

In one set of tests, the engineers placed a short stick of spaghetti lengthwise between the fingers of the robotic hand. When the gripper crashed into a fixed object, the device detected the external force being applied, which caused the magnets to adjust their position, temporarily reducing the stiffness of the grip and allowing the gripper to absorb some of the energy from the collision.

The end result? The spaghetti stick stayed in one piece.

Next steps in development

Esfahani notes that the gripper his team is developing can be attached to commercially available robot arms that are already in use in many facilities. This could lower the cost of adapting the technology for companies interested in improving the safety and capabilities of existing machines.

Esfahani is launching a startup company to commercialize the gripper, licensing technology from UB.

His team has received $55,000 from the Buffalo Fund: Accelerator -- funded by the Innovation Hub, which is administered by UB and supported by Empire State Development -- to further develop the robotic hand. In addition to refining the current design of the gripper, the team may also explore advances such as adding a third finger.

Researchers who have been involved in designing and testing the gripper include PhD student Sri Sadhan Jujjavarapu and Memar, the co-author on the new spaghetti stick study, who has received his PhD from UB and is now a postdoctoral research scientist at Facebook Reality Labs.

WASHINGTON --Researchers have developed advanced optical security features that use a two-piece metamaterial system to create a difficult-to-replicate optical phenomenon. Metamaterials are engineered to have a property that is not found in naturally occurring materials. The new security features could offer improved forgery protection for high-value products or banknotes and enhance encryption of information such as pin numbers that are physically sent to recipients.

Optical security features are often used today to verify the authenticity of currency, identification cards and valuable products such as electronics. These features include holograms that change color at different viewing angles or patterns that appear only under ultraviolet light. Security features with many hard-to-replicate features are the most secure because they are difficult to reproduce.

"An ideal optical security feature must be hard to copy by unlicensed people, easy to produce in mass, and be interrogated conveniently," said research team leader Gokhan Bakan from the University of Manchester in the UK. "Our approach satisfies all these requirements and could offer more secure goods and information transactions for everyone."

In The Optical Society (OSA) journal Optics Letters, the researchers describe a system in which two thin optical pieces must be placed together to form a metamaterial that reveals a hidden message or QR code that is readable to the naked eye. Re-encryption is performed by peeling off the top part, which contains no information, from the bottom portion that encodes a message.

To protect sensitive information such as a credit card pin, a customer could get the top part of the security feature (the key) from the bank at the time of application. When the encrypted pin arrives by mail the customer would use the key to reveal the pin. If the printout with the encrypted pin number on it is stolen, it would be impossible to decrypt it without the key.

Revealing the secret message

The new two-part security features have a bottom portion that is formed by coating a thin insulating material, or dielectric, on a silver film that is about 120 nanometers thick. This bottom portion is essentially a mirror in that it reflects most of the incoming light. Because its optical properties are defined by the silver film and not affected by the dielectric layer's thickness a message can be hidden on the dielectric by simply adding more dielectric in the shape of the message.

The top part of the security feature is a transparent elastic substrate coated with a metal layer that is about 10 nanometers thick. This part, which acts as a key, doesn't hold any information and appears semi-transparent. When the two parts are put together, with the thin metal on the top part facing the bottom part, it forms an optical cavity whose properties, such as surface color, strongly depend on the dielectric thickness. Thus, as the two pieces are placed together, a stark color contrast appears and reveals the hidden message, which is readable to the naked eye. The approach can be used to create keys that are specific to each message or to make a master key that would work for any message.

"When the two parts of the security feature are stuck together, it creates an optical phenomenon known as the plasmonics-enhanced optical cavity effect," said Bakan. "Although this effect is commonly employed for a variety of applications such as optical filters, we uniquely separated the optical cavity into two, allowing information to be hidden in one part in a way that can only be revealed with the right key."

Flexible security

The researchers demonstrated their new approach by encoding QR codes on rigid substrates as well as flexible substrates that could be used on almost any surface, including banknotes. The QR codes were invisible to the naked eye until an adhesive patch made of the transparent elastic substrate was applied. They also used the approach to encode various patterns and words.

Although the researchers demonstrated an application specific to optical security, the approach could also be used for optical sensing for chemical or biological applications. For example, if certain proteins attached to a thin-film, the modular metamaterial could produce a read-out that was visible to the naked-eye or readable to a camera.

The researchers plan to further develop the new optical security feature by using it with other optical phenomena. They also want to communicate the technology with developers of security tags and banks so that the technology could be tested and developed for real-world applications.

"Our research shows that converting static optical features to modular ones can open up completely new applications," said Bakan. "This offers a new perspective that scientists could use to expand other established optical methods."

Colloidal suspensions heterogenous mixtures of particles with diameters of about 2-500 nanometers, which are permanently suspended in a second phase, usually a liquid. Owing to the small particle size of the suspended material, a colloid does not separate into its characteristic components even if allowed to remain undisturbed, nor can the suspended material be separated through filtration. Colloids are distinguished from other types of mixtures by several important distinctive properties, one of which is the electrokinetic force in colloidal suspensions, also known as the "zeta potential."

To explore zeta potential, we must first understand what a "slipping surface" is. A slipping surface is an "electrical double layer" that forms on the surface of any object when it is exposed to a fluid. This double layer consists of one layer of charges that adhere to the surface of the object as a result of chemical interactions, and a second layer of opposite charges that are attracted to the first layer. Due to the attraction between these two layers of opposite "ions" or charges, an electric potential is created, and this is the zeta potential. The zeta potential occurs in double layers on the surface of particles suspended in colloids as well.

Prof Hiroyuki Ohshima of Tokyo University of Science has been a lifelong theoretical researcher of electrokinetic phenomena such as the movement of colloidal particles in an electric field and electrostatic interactions between colloidal particles. He has recently summarized some of the major findings in his field in a review published in the journal Advances in Colloid and Interface Science. He asserts the importance of zeta potential in colloidal surface chemistry. According to him, "the dispersion stability of colloidal particles, which is one of the most important issues in colloid surface chemistry, greatly depends on the zeta potential of the particles."

Zeta potential is calculated based on the electrophoretic mobility of the particles. Until now, the no-slip boundary condition of the fluid, which assumes that the fluid will have zero velocity relative to the boundary, has been applied when calculating the zeta potential. However, while this condition is applicable to particles with a hydrophilic ("water-loving") surface, it cannot be applied to particles with a hydrophobic ("water-shy") surface. In this case, the Navier boundary condition, which considers the relative velocity of the fluid, is applied.

In the Navier boundary condition, the effect of the hydrodynamic slip is characterized by the slipping length. When the surface is hydrophilic, the slipping length is considered to be zero, and it progressively increases with the increase in hydrophobicity of the surface, where the molecules of the particle surface weakly interact with the molecules in the surrounding phase so that liquid slip occurs. In accordance, an infinitely large slipping length theoretically corresponds with a completely hydrophobic surface. From this information, theoretical calculations show that electrophoretic mobility and sedimentation potential increase with increasing slipping length.

According to Prof Ohshima, what is more interesting is that if we accept the possibility of the presence of a slipping surface on a spherical solid colloidal particle, we can observe that the electrokinetic properties of this solid particle will be hydrodynamically similar to those of a liquid drop.

These findings highlight the importance of reconsidering how the electrokinetic properties of hydrophilic and hydrophobic surfaces vary and showcase how they affect the dynamics of colloidal suspensions. Prof Ohshima concludes, "We have constructed a general theory describing various electrokinetic phenomena of particles with a sliding surface. By applying this theory, we could expect a more accurate evaluation of zeta potential and colloidal particle dispersion stability in the future."

ANN ARBOR, Mich. - It's an age-old debate: are time-outs bad for kids?

Now, a new study suggests that despite sometimes getting a bad rap in the news, the common disciplinary strategy isn't linked to harmful effects in children.

Researchers compared emotional and behavioral health between kids whose parents reported using time-outs and those who didn't over a roughly eight-year period. The result: no difference.

"Some reports in the media and by select organizations have suggested that time-out is ineffective and even harmful," says lead author Rachel Knight, Ph.D., pediatric psychologist at University of Michigan C.S. Mott Children's Hospital.

"There are some alarming claims that time-outs can damage the parent-child relationship and negatively affect emotional health. But the research simply doesn't support those claims. We did not find a relationship between time-outs and negative side effects in children."

Researchers analyzed national data from the Early Head Start Research and Evaluation study tracking families at three different time points. Children's positivity and negativity towards parents, mental health and social skills were among measures evaluated at 36 months-old, pre-kindergarten and in fifth grade.

There was no association between reported use of time-outs and negative symptoms in later childhood, including anxiety, depression, internalizing or externalizing problems, aggression, rule-breaking behavior, or self-control, according to the findings in the Journal of Developmental and Behavioral Pediatrics.

There also weren't any differences in the measure of creativity when the children were about to enter kindergarten.

Knight says that she and fellow children's health experts were concerned by the amount of inaccurate information widely available about time-outs.

"Parents are constantly questioning whether they are doing the right thing for their children," she says.

"Unfortunately the first place many parents go for advice is the Internet, social media or friends - not a medical provider. There is a lot of conflicting information on the Web that isn't vetted or accurate."

A previous Mott-led study found that close to 30% of websites portrayed time-out negatively. Some have criticized the disciplinary strategy as having the opposite desired effect, possibly leading to escalating problem behaviors. A high-profile 2014 Time Magazine article "Are Time-Outs Hurting Your Children?" also recently re-ignited the debate.

Parents may not be aware that time-out is one of the only child discipline strategies currently recommended by the American Academy of Pediatrics, Knight says. Time-out has been shown to be effective in addressing behavior challenges across several ages, including infants, toddlers and preschoolers, school-age children and adolescents.

"There's a wealth of research on how effective time-outs can be in reducing problematic behavior when they are used appropriately," she says. "It's a parenting strategy that's often misunderstood and misused."

Consistency, structure, a calm demeanor and positive environment are keys to effectively using time-outs, Knight says. The process should be pre-planned and understood by both parents and children rather than being introduced in the heat of the moment to avoid yelling or scolding.

"Catching" a child exhibiting good behavior is also just as important as enforcing consequences when they break the rules, she notes.

Further studies are needed, Knight says, to continue evaluating specific claims made against time outs and both their short-term and long-term effects across different populations and ages.

Experts also need to find more effective ways to communicate evidence-based information to parents and caregivers.

"As we further our understanding about how different parenting strategies impact children, we need to present findings in an easily digestible and accessible way for the public," she says.

"Our goal is to debunk misconceptions and promote the use of highly effective, evidence-based strategies that will best guide parents and families."

TROY, N.Y. -- A promising semiconductor material could be improved if flaws previously thought irrelevant to performance are reduced, according to research published today in Nature Communications. A group of researchers at Rensselaer Polytechnic Institute and other universities has shown that a specific defect impacts the ability of halide perovskite to hold energy derived from light in the form of electrons.

"Defects could be good or bad in semiconductors," said Jian Shi, associate professor of materials science engineering. "For some reason, people did not pay attention to dislocations in halide perovskite, but we have shown that this defect is a problem in halide perovskite."

Research on halide perovskite has rapidly improved the efficiency of the material from about a 3% conversion of light to electrical energy to 25% -- equivalent to state-of-the-art silicon solar cells -- over the course of a decade. Researchers wrestled with silicon for decades to reach that material's current level of efficiency.

Halide perovskite also has promising carrier dynamics, which are roughly defined as the length of time that light energy absorbed by the material is retained in the form of an excited electron. To make a good prospect for solar energy conversion, electrons in the material must retain their energy long enough to be harvested by an electrode attached to the material, thus completing the conversion of light to electrical energy.

The material had long been considered "defect tolerant," meaning flaws like missing atoms, shoddy bonds across grains of the crystal, and a mismatch known as crystallographic dislocation were not believed to have much impact on efficiency. More recent research has questioned that assumption and found that some defects do affect aspects of the crystal's performance.

Shi's team tested whether the defect of crystallographic dislocation impacts carrier dynamics by growing the crystal on two different substrates. One substrate had a strong interaction with the halide perovskite as it was being deposited, producing a higher density of dislocations. The other had a weaker interaction and produced a lower density of dislocations.

The results show that dislocations negatively impact the carrier dynamics of halide perovskite. Reducing dislocation densities by more than one order of magnitude is found to lead to an increase of electron lifetime by four times.

"A conclusion is that halide perovskite has a similar dislocation effect as conventional semiconductors," Shi said. "We need to be careful of dislocations in halide perovskite, which is a factor people have been ignoring as they work on this material."

Shi's last significant work on halide perovskite revealed the role of pressure on this semiconductor's optical properties published in Science Advances in 2018.

At Rensselaer, Shi was joined by researchers in both the Department of Materials Science and Engineering and Department of Physics, Applied Physics and Astronomy. Researchers from the Kunming University of Science and Technology, Tsinghua University, University of Science and Technology Beijing, Forschungszentrum Julich, and Brown University also contributed to the research.

WASHINGTON, D.C., September 12, 2019 -- African Americans are seeing growth in many engineering and physical sciences fields, but they are not progressing at the same rate when compared to the general population.

A report from the American Institute of Physics (AIP) Statistical Research Center (SRC) examined the number of bachelor's degrees earned from 2005 to 2015 and separated out the numbers for African Americans from the rest of the students. The data was gathered by the National Center for Education Statistics from postsecondary institutions in the United States.

The SRC found the number of degrees earned by African Americans in physical sciences fields grew by 36% over 10-year period, which was less than the growth of degrees by all students, 55%, during the same time.

In four of the seven physical sciences fields, the number of degrees earned by African Americans grew faster (by percentage) than the growth overall, but those fields were among the smallest number of degrees earned. The other fields, which had larger numbers of graduates, showed a slower than overall growth rate.

In engineering, the number of bachelor's degrees earned by African Americans increased by 19%, less than half of the overall growth in the field of 44%.

Only two fields in engineering (civil engineering and materials engineering) showed growth in the number of African American graduates when compared to the rest of the students in those fields. The other seven disciplines showed slow or negative growth.

To get the complete statistical breakdown, visit the Statistical Research Center online.

SRC senior survey scientist Laura Merner said it was heartening to see growth for African Americans overall in the science and engineering fields, but it is not fast enough.

"We're hopeful that this report could help intervention programs to be more successful to improve representation," Merner said. "Clearly, more research is needed to find out why African Americans are underrepresented in these fields, and there is still work that needs to be done."

The number of African Americans earning bachelor's degrees in the physical sciences and engineering has grown during the 10-year period from just under 6,000 degrees earned in 2005 to more than 7,000 degrees earned in 2015. While more African Americans earned degrees in 2015 than in 2005 in the physical sciences, for engineering, the number for men earning degrees showed an increase while the number of women earning degrees decreased.