Tech

It's not an electron. But it sure does act like one.

Northwestern University researchers have made a strange and startling discovery that nanoparticles engineered with DNA in colloidal crystals -- when extremely small -- behave just like electrons. Not only has this finding upended the current, accepted notion of matter, it also opens the door for new possibilities in materials design.

"We have never seen anything like this before," said Northwestern's Monica Olvera de la Cruz, who made the initial observation through computational work. "In our simulations, the particles look just like orbiting electrons."

With this discovery, the researchers introduced a new term called "metallicity," which refers to the mobility of electrons in a metal. In colloidal crystals, tiny nanoparticles roam similarly to electrons and act as a glue that holds the material together.

"This is going to get people to think about matter in a new way," said Northwestern's Chad Mirkin, who led the experimental work. "It's going to lead to all sorts of materials that have potentially spectacular properties that have never been observed before. Properties that could lead to a variety of new technologies in the fields of optics, electronics and even catalysis."

The paper will publish Friday, June 21 in the journal Science.

Olvera de la Cruz is the Lawyer Taylor Professor of Materials Science and Engineering in Northwestern's McCormick School of Engineering. Mirkin is the George B. Rathmann Professor of Chemistry in Northwestern's Weinberg College of Arts and Sciences.

Mirkin's group previously invented the chemistry for engineering colloidal crystals with DNA, which has forged new possibilities for materials design. In these structures, DNA strands act as a sort of smart glue to link together nanoparticles in a lattice pattern.

"Over the past two decades, we have figured out how to make all sorts of crystalline structures where the DNA effectively takes the particles and places them exactly where they are supposed to go in a lattice," said Mirkin, founding director of the International Institute of Nanotechnology.

In these previous studies, the particles' diameters are on the tens of nanometers length scale. Particles in these structures are static, fixed in place by DNA. In the current study, however, Mirkin and Olvera de la Cruz shrunk the particles down to 1.4 nanometers in diameter in computational simulations. This is where the magic happened.

"The bigger particles have hundreds of DNA strands linking them together," said Olvera de la Cruz. "The small ones only have four to eight linkers. When those links break, the particles roll and migrate through the lattice holding together the crystal of bigger particles."

When Mirkin's team performed the experiments to image the small particles, they found that Olvera de la Cruz's team's computational observations proved true. Because this behavior is reminiscent to how electrons behave in metals, the researchers call it "metallicity."

"A sea of electrons migrates throughout metals, acting as a glue, holding everything together," Mirkin explained. "That's what these nanoparticles become. The tiny particles become the mobile glue that holds everything together."

Olvera de la Cruz and Mirkin next plan to explore how to exploit these electron-like particles in order to design new materials with useful properties. Although their research used gold nanoparticles, Olvera de la Cruz said "metallicity" applies to other classes of particles in colloidal crystals.

"In science, it's really rare to discover a new property, but that's what happened here," Mirkin said. "It challenges the whole way we think about building matter. It's a foundational piece of work that will have a lasting impact."

Fast facts:

The liver is the only solid organ that can regenerate itself in mammals, but what confers this special property to the liver has not been uncovered, despite decades of research.

NYU Abu Dhabi researchers suggest that a novel mechanism driven by the epigenome promotes liver regeneration.

The epigenome refers to the code that packages the DNA so that some parts can be activated (i.e. genes) and some parts remain in dormant domains - these dormant parts largely contain remnants of old viruses or transposable elements.

Epigenetic compensation is when parts of the epigenome that usually have one role - i.e. to suppress genes, are co-opted to do a different job - when another part of the epigenome is missing modifications in the packaging material of the DNA influence how much a genetic program is active or repressed. These modifications do not change the DNA sequence, but instead, affect how cells read genes.

This study reports that the primary role of the epigenome is to protect the genome against the activation of genomic parasites (transposable elements).

The new findings have been published in the journal Developmental Cell.

In a recent study published in the journal Developmental Cell, NYU Abu Dhabi researchers have reported a new way in which the liver is primed to regenerate itself. They found that by stripping parts of the epigenome, which play a primary role in repressing "jumping genes" (i.e. transposable elements), other epigenetic marks were redistributed.

This newly discovered form of epigenetic compensation protects the genome against transposable elements activation, but takes these compensating epigenetic marks away from their normal job in regulating gene expression. The result is that when these marks are taken away from their normal role, the genes they usually repress are activated early and are sustained during the regenerative response to the surgical removal of part of the liver.

This type of surgery is relevant to humans, as it is used in resection of liver tumors and the regenerative response is essential for the liver to respond to damage. The findings are a significant advance in the understanding of the liver regeneration process, which is unique among the organs of humans, mice, and other mammals.

The researchers from NYU Abu Dhabi's Sadler Lab, led by Associate Professor of Biology Kirsten Sadler Edepli, removed a key epigenetic regulator, UHRF1 in the mouse liver. They found when they removed part of the liver, the remaining lobes responded more readily by activating pro-regenerative genes activated earlier, and this regeneration program stayed active longer, resulting in enhanced liver regeneration.

The epigenome refers to the code that packages the genome so that some parts can be activated (i.e. genes) and some parts remain in dormant domains - these dormant parts largely contain remnants of old viruses or transposable elements, which were made famous by the 1983 Nobel Prize discovery by Barbara McClintok.

Surprisingly, instead of causing massive activation of transposable elements or an immune response to mitigate the unleashing of transposable elements, as found in previous experiments, they discovered that there is an extra layer of protection by another repressive epigenetic mark (H3K27me3). This mark was redistributed from gene promoters to suppress transposable elements when DNA methylation was missing, thereby compensating for the loss of DNA methylation. When this mark is redistributed, it is removed from its role in repressing genes that promote liver regeneration. Thus, livers lacking UHRF1 are able to regenerate faster.

"When H3K27me3 compensates for the loss of DNA methylation, this results in a favorable epigenetic environment for liver regeneration," said Sadler Edepli. "It will be exciting to explore whether drugs that can modify the epigenome have the potential to induce epigenetic compensation and increase the liver's ability to regenerate in cases of liver disease or failure." Shuang Wang, a post-doctoral fellow in the Sadler Edepli laboratory who worked in her group at Icahn School of Medicine at Mount Sinai, led the study in collaboration with members of the lab at NYUAD as well as Emily Bernstein and Amaia Lujambio in NY.

Hearing aids, dental crowns, and limb prosthetics are some of the medical devices that can now be digitally designed and customized for individual patients, thanks to 3-D printing. However, these devices are typically designed to replace or support bones and other rigid parts of the body, and are often printed from solid, relatively inflexible material.

Now MIT engineers have designed pliable, 3-D-printed mesh materials whose flexibility and toughness they can tune to emulate and support softer tissues such as muscles and tendons. They can tailor the intricate structures in each mesh, and they envision the tough yet stretchy fabric-like material being used as personalized, wearable supports, including ankle or knee braces, and even implantable devices, such as hernia meshes, that better match to a person's body.

As a demonstration, the team printed a flexible mesh for use in an ankle brace. They tailored the mesh's structure to prevent the ankle from turning inward -- a common cause of injury -- while allowing the joint to move freely in other directions. The researchers also fabricated a knee brace design that could conform to the knee even as it bends. And, they produced a glove with a 3-D-printed mesh sewn into its top surface, which conforms to a wearer's knuckles, providing resistance against involuntary clenching that can occur following a stroke.

"This work is new in that it focuses on the mechanical properties and geometries required to support soft tissues," says Sebastian Pattinson, who conducted the research as a postdoc at MIT.

Pattinson, now on the faculty at Cambridge University, is the lead author of a study published in the journal Advanced Functional Materials. His MIT co-authors include Meghan Huber, Sanha Kim, Jongwoo Lee, Sarah Grunsfeld, Ricardo Roberts, Gregory Dreifus, Christoph Meier, and Lei Liu, as well as Sun Jae Professor in Mechanical Engineering Neville Hogan and associate professor of mechanical engineering A. John Hart.

Riding collagen's wave

The team's flexible meshes were inspired by the pliable, conformable nature of fabrics.

"3-D-printed clothing and devices tend to be very bulky," Pattinson says. "We were trying to think of how we can make 3-D-printed constructs more flexible and comfortable, like textiles and fabrics."

Pattinson found further inspiration in collagen, the structural protein that makes up much of the body's soft tissues and is found in ligaments, tendons, and muscles. Under a microscope, collagen can resemble curvy, intertwined strands, similar to loosely braided elastic ribbons. When stretched, this collagen initially does so easily, as the kinks in its structure straighten out. But once taut, the strands are harder to extend.

Inspired by collagen's molecular structure, Pattinson designed wavy patterns, which he 3-D-printed using thermoplastic polyurethane as the printing material. He then fabricated a mesh configuration to resemble stretchy yet tough, pliable fabric. The taller he designed the waves, the more the mesh could be stretched at low strain before becoming more stiff -- a design principle that can help to tailor a mesh's degree of flexibility and helped it to mimic soft tissue.

The researchers printed a long strip of the mesh and tested its support on the ankles of several healthy volunteers. For each volunteer, the team adhered a strip along the length of the outside of the ankle, in an orientation that they predicted would support the ankle if it turned inward. They then put each volunteer's ankle into an ankle stiffness measurement robot -- named, logically, Anklebot -- that was developed in Hogan's lab. The Anklebot moved their ankle in 12 different directions, and then measured the force the ankle exerted with each movement, with the mesh and without it, to understand how the mesh affected the ankle's stiffness in different directions.

In general, they found the mesh increased the ankle's stiffness during inversion, while leaving it relatively unaffected as it moved in other directions.

"The beauty of this technique lies in its simplicity and versatility. Mesh can be made on a basic desktop 3-D printer, and the mechanics can be tailored to precisely match those of soft tissue," Hart says.

Stiffer, cooler drapes

The team's ankle brace was made using relatively stretchy material. But for other applications, such as implantable hernia meshes, it might be useful to include a stiffer material, that is at the same time just as conformable. To this end, the team developed a way to incorporate stronger and stiffer fibers and threads into a pliable mesh, by printing stainless steel fibers over regions of an elastic mesh where stiffer properties would be needed, then printing a third elastic layer over the steel to sandwich the stiffer thread into the mesh.

The combination of stiff and elastic materials can give a mesh the ability to stretch easily up to a point, after which it starts to stiffen, providing stronger support to prevent, for instance, a muscle from overstraining.

The team also developed two other techniques to give the printed mesh an almost fabric-like quality, enabling it to conform easily to the body, even while in motion.

"One of the reasons textiles are so flexible is that the fibers are able to move relative to each other easily," Pattinson says. "We also wanted to mimic that capability in the 3-D-printed parts."

In traditional 3-D printing, a material is printed through a heated nozzle, layer by layer. When heated polymer is extruded it bonds with the layer underneath it. Pattinson found that, once he printed a first layer, if he raised the print nozzle slightly, the material coming out of the nozzle would take a bit longer to land on the layer below, giving the material time to cool. As a result, it would be less sticky. By printing a mesh pattern in this way, Pattinson was able to create a layers that, rather than being fully bonded, were free to move relative to each other, and he demonstrated this in a multilayer mesh that draped over and conformed to the shape of a golf ball.

Finally, the team designed meshes that incorporated auxetic structures -- patterns that become wider when you pull on them. For instance, they were able to print meshes, the middle of which consisted of structures that, when stretched, became wider rather than contracting as a normal mesh would. This property is useful for supporting highly curved surfaces of the body. To that end, the researchers fashioned an auxetic mesh into a potential knee brace design and found that it conformed to the joint.

"There's potential to make all sorts of devices that interface with the human body," Pattinson says. Surgical meshes, orthoses, even cardiovascular devices like stents -- you can imagine all potentially benefiting from the kinds of structures we show."

LAWRENCE -- New research from the University of Kansas shows machine learning is capable of identifying insects that spread the incurable disease called Chagas with high precision, based on ordinary digital photos. The idea is to give public health officials where Chagas is prevalent a new tool to stem the spread of the disease and eventually to offer identification services directly to the general public.

Chagas is particularly nasty because most people who have it don't know they've been infected. But according to the Centers for Disease Control and Prevention, some 20 percent to 30 percent of the 8 million people with Chagas worldwide are struck at some later point with heart rhythm abnormalities that can bring on sudden death; dilated hearts that don't pump blood efficiently; or a dilated esophagus or colon.

The disease is caused most often when triatomine bugs -- more commonly known as "kissing bugs" -- bite people and transmit the parasite Trypanosoma cruzi into their bloodstreams. Chagas is most prevalent in rural areas of Mexico, Central America and South America.

A recent undertaking at KU, called the Virtual Vector Project, sought to enable public health officials to identify triatomine that carry Chagas with their smartphones, using a kind of portable photo studio for taking pictures of the bugs.

Now, a graduate student at KU has built on that project with proof-of-concept research showing artificial intelligence can recognize 12 Mexican and 39 Brazilian species of kissing bugs with high accuracy by analyzing ordinary photos -- an advantage for officials looking to cut the spread of Chagas disease.

Ali Khalighifar, a KU doctoral student at the Biodiversity Institute and the Department of Ecology and Evolutionary Biology, headed a team that just published findings in the Journal of Medical Entomology. To identify the kissing bugs from regular photos, Khalighfar and his colleagues worked with open-source, deep-learning software from Google, called TensorFlow that is similar to the technology underpinning Google's reverse image search.

"Because this model is able to understand, based on pixel tones and colors, what is involved in one image, it can take out the information and analyze it in a way the model can understand -- and then you give them other images to test and it can identify them with a really good identification rate," Khalighifar said. "That's without preprocessing -- you just start with raw images, which is awesome. That was the goal. Previously, it was impossible to do the same thing as accurately and certainly not without preprocessing the images."

Khalighifar and his coauthors -- Ed Komp, researcher at KU's Information and Telecommunication Technology Center, Janine M. Ramsey of Mexico's Instituto Nacional de Salud Publica, Rodrigo Gurgel-Gonçalves of Brazil's Universidade de Brasília, and A. Townsend Peterson, KU Distinguished Professor of Ecology and Evolutionary Biology and senior curator with the KU Biodiversity Institute -- trained their algorithm with 405 images of Mexican triatomine species and 1,584 images of Brazilian triatomine species.

At first, the team was able to achieve, "83.0 and 86.7 percent correct identification rates across all Mexican and Brazilian species, respectively, an improvement over comparable rates from statistical classifiers," they write. But after adding information about kissing bugs' geographic distributions into the algorithm, the researchers boosted the accuracy of identification to 95.8 percent for Mexican species and 98.9 percent for Brazilian species.

According to Khalighifar, the algorithm-based technology could allow public health officials and others to identify triatomine species with an unprecedented level of accuracy, to better understand disease vectors on the ground.

"In the future, we're hoping to develop an application or a web platform of this model that is constantly trained based on the new images, so it's always being updated, that provides high-quality identifications to any interested user in real time," he said.

Khalighifar now is applying a similar approach using TensorFlow for instant identification of mosquitoes based on the sounds of their wings and frogs based on their calls.

"I'm working right now on mosquito recordings," he said. "I've shifted from image processing to signal processing of recordings of the wing beats of mosquitoes. We get the recordings of mosquitoes using an ordinary cell phone, and then we convert them from recordings to images of signals. Then we use TensorFlow to identify the mosquito species. The other project that I'm working right now is frogs, with Dr. Rafe Brown at the Biodiversity Institute. And we are designing the same system to identify those species based on the calls given by each species."

While often artificial intelligence is popularly portrayed as a job-killing threat or even an existential threat to humanity, Khalighifar said his research showed how AI could be a boon to scientists studying biodiversity.

"It's amazing -- AI really is capable of doing everything, for better or for worse," he said. "There are uses appearing that are scary, like identifying Muslim faces on the street. Imagine, if we can identify frogs or mosquitoes, how easy it might be to identify human voices. So, there are certainly dark sides of AI. But this study shows a positive AI application -- we're trying to use the good side of that technology to promote biodiversity conservation and support public health work."

WASHINGTON (June 20, 2019) -- Patients with psoriasis frequently use complementary or alternative therapies to treat their symptoms, according to survey results published by dermatologists from the George Washington University (GW) in the Journal of the American Academy of Dermatology.

According to the Centers for Disease Control and Prevention, psoriasis is chronic autoinflammatory skin disease that speeds up the growth cycle of skin cells, which causes raised, red, scaly patches to appear on the skin. Treatments for psoriasis range from topical ointments to ultraviolet light therapy to drugs. Psoriasis is associated with other serious conditions, such as diabetes, heart disease, and depression.

Through a survey distributed by the National Psoriasis Foundation, a team led by Adam Friedman, MD, interim chair of the Department of Dermatology at the GW School of Medicine and Health Sciences, found that patients with psoriasis typically turned to complementary or alternative medicine when their traditional medications failed or presented harsh side effects.

"Patients turn to these treatments because what was initially prescribed is not working out for them," explained Friedman. "But what we found through the survey is that patients may not completely understand what products will work best for them."

The survey found that patients reported using complementary and alternative medicine that have not previously exhibited efficacy or have not been studied for the treatment of psoriasis. Vitamins D and B12 were frequently reported, though neither of which have documented efficacy against the disease. In contrast, indigo naturalis -- a plant extract widely used in Traditional Chinese Medicine and recognized as a therapy for several inflammatory conditions -- has shown efficacy, but was not reported in the survey. Dead Sea treatments were commonly reported and have shown therapeutic benefit.

"In addition to the chosen treatments, we also found that less than half of the respondents would recommend complementary or alternative therapies to others," Friedman said. "This could be a result of using therapies supported by limited evidence."

Acknowledging that these treatments are part of patients' armament, Friedman and his team suggest that educational initiatives that enable physicians to discuss evidence-based complementary and alternative medicine may improve patient satisfaction and outcomes.

The rings of Uranus are invisible to all but the largest telescopes -- they weren't even discovered until 1977 -- but they're surprisingly bright in new heat images of the planet taken by two large telescopes in the high deserts of Chile.

The thermal glow gives astronomers another window onto the rings, which have been seen only because they reflect a little light in the visible, or optical, range and in the near-infrared. The new images taken by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Telescope (VLT) allowed the team for the first time to measure the temperature of the rings: a cool 77 Kelvin, or 77 degrees above absolute zero -- the boiling temperature of liquid nitrogen and equivalent to 320 degrees below zero Fahrenheit.

The observations also confirm that Uranus's brightest and densest ring, called the epsilon ring, differs from the other known ring systems within our solar system, in particular the spectacularly beautiful rings of Saturn.

"Saturn's mainly icy rings are broad, bright and have a range of particle sizes, from micron-sized dust in the innermost D ring, to tens of meters in size in the main rings," said Imke de Pater, a UC Berkeley professor of astronomy. "The small end is missing in the main rings of Uranus; the brightest ring, epsilon, is composed of golf ball-sized and larger rocks."

By comparison, Jupiter's rings contain mostly small, micron-sized particles (a micron is a thousandth of a millimeter). Neptune's rings are also mostly dust, and even Uranus has broad sheets of dust between its narrow main rings.

"We already know that the epsilon ring is a bit weird, because we don't see the smaller stuff," said graduate student Edward Molter. "Something has been sweeping the smaller stuff out, or it's all glomming together. We just don't know. This is a step toward understanding their composition and whether all of the rings came from the same source material, or are different for each ring."

Rings could be former asteroids captured by the planet's gravity, remnants of moons that crashed into one another and shattered, the remains of moons torn apart when they got too close to Uranus, or debris remaining from the time of formation 4.5 billion years ago.

The new data were published this week in the Astronomical Journal. De Pater and Molter led the ALMA observations, while Michael Roman and Leigh Fletcher from the University of Leicester in the United Kingdom led the VLT observations.

"The rings of Uranus are compositionally different from Saturn's main ring, in the sense that in optical and infrared, the albedo is much lower: they are really dark, like charcoal," Molter said. "They are also extremely narrow compared to the rings of Saturn. The widest, the epsilon ring, varies from 20 to 100 kilometers wide, whereas Saturn's are 100's or tens of thousands of kilometers wide."

The lack of dust-sized particles in Uranus's main rings was first noted when Voyager 2 flew by the planet in 1986 and photographed them. The spacecraft was unable to measure the temperature of the rings, however.

To date, astronomers have counted a total of 13 rings around the planet, with some bands of dust between the rings. The rings differ in other ways from those of Saturn.

"It's cool that we can even do this with the instruments we have," he said. "I was just trying to image the planet as best I could and I saw the rings. It was amazing."

Both the VLT and ALMA observations were designed to explore the temperature structure of Uranus' atmosphere, with VLT probing shorter wavelengths than ALMA.

"We were astonished to see the rings jump out clearly when we reduced the data for the first time," Fletcher said.

This presents an exciting opportunity for the upcoming James Webb Space Telescope, which will be able provide vastly improved spectroscopic constraints on the Uranian rings in the coming decade.

More than 5 million cancer survivors in the United States experience chronic pain, almost twice the rate in the general population, according to a study published by Mount Sinai researchers in JAMA Oncology in June.

Researchers used the National Health Interview Survey, a large national representative dataset from the U.S. Centers for Disease Control and Prevention, to estimate the prevalence of chronic pain among cancer survivors. They found that about 35 percent of cancer survivors have chronic pain, representing 5.39 million patients in the United States.

"This study provided the first comprehensive estimate of chronic pain prevalence among cancer survivors," said corresponding author Changchuan Jiang, MD, MPH, a medical resident at Mount Sinai St. Luke's and Mount Sinai West. "These results highlight the important unmet needs of pain management in the large, and growing cancer survivorship community."

Specific types of cancer--such as bone, kidney, throat, and uterine--also had a higher incidence of chronic and severe pain that restricted daily activity. Chronic pain was more prevalent in survivors who were unemployed and had inadequate insurance.

Chronic pain is one of the most common long-term effects of cancer treatment and has been linked with an impaired quality of life, lower adherence to treatment, and higher health care costs. This study is important because a better understanding of the epidemiology of pain in cancer survivors can help inform future health care educational priorities and policies.

Researchers from the American Cancer Society, Memorial Sloan Kettering Cancer Center, and the University of Virginia were part of the study team.

Snowflakes that cover mountains or linger under tree canopies are a vital freshwater resource for over a billion people around the world. To help determine how much freshwater is stored in snow, a team of NASA-funded researchers is creating a computer-based tool that simulates the best way to detect snow and measure its water content from space.

Snow's water content, or snow water equivalent (SWE) is a "holy grail for many hydrologists," said Bart Forman, the project's principal investigator and a professor with the University of Maryland, College Park. When snow melts, the ensuing puddle of water is its SWE.

In western U.S. states, snow is the main source of drinking water and water from snow is a major contributor to hydroelectric power generation and agriculture.

Some changes in snowfall patterns are indicators of climate change. For instance, warmer temperatures cause water to fall as rain instead of snow. As a result, some mountains are not able to hold water in the form of snowpack like they used to, which means rain inundates rivers and floods are more intense. When flood season is over, droughts can be more severe.

Forman's new approach follows efforts by NASA to study SWE from satellites, airplanes and the field. The Moderate-resolution Imaging Spectroradiometer (MODIS) is an instrument aboard two satellites that captures daily images of Earth. MODIS can identify snow-covered land and ice on lakes and large rivers. The Global Precipitation Measurement mission (GPM), an international constellation of satellites, can observe rain and falling snow over the entire globe every two to three hours.

In addition to space-based observations, NASA runs a campaign closer to home called SnowEX. The campaign is a five-year program that includes airborne observations and then field work to reveal what satellite efforts do not. SnowEX allows researchers to examine complex terrains that can be difficult to characterize from space. Next winter's campaign will collaborate with the Airborne Snow Observatory, which measures snow depth and snow characteristics.

The importance of snow and its water

"We would love to have a global map of SWE," said Edward Kim, a research scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. However, there is no single technique that can measure SWE globally because snow properties vary depending on where it lands, Kim said. It often forms a deeper layer in forests, where it is sheltered from the Sun, but keeps a shallower profile in the tundra and prairie, where it is exposed to wind and higher temperatures.

Snow changes its shape as it falls to the surface and then continues to change in its resting place. Its shape can determine which sensor is able to observe it, Kim said, adding another complexity to estimated SWE.

Forman and his team's new tool will determine the most effective combination of satellite-based sensors to produce the most data. "The tool will show us how to make intelligent choices about how to combine sensors," Kim said.

A tale of different sensors

The tool evaluates three different types of Earth-orbiting sensors: radar, radiometer, and lidar.

The team looked at radar and radiometer information from existing sensors, such as the Advanced Microwave Scanning Radiometer 2 (AMSR2) radiometer. The sensor launched as a partnership led by the Japan Aerospace Exploration Agency (JAXA) to capture microwave emissions from Earth's surface and atmosphere. It aims to identify snow cover, sea surface temperatures, soil moisture and other factors critical to understanding Earth's climate.

For radar observations, the team included data from the European Space Agency (ESA) Copernicus Sentinel 1A and 1B satellites, which monitor land and ocean surfaces.

In addition to including radar and radiometer sensors, which are currently monitoring snow from space, the new tool's simulation includes lidar; lidar has flown aboard airplanes to measure snow over specified areas. For instance, the SnowEx campaign and NASA's Airborne Snow Observatory use lidar to determine snow depth and SWE. "We can help explore the question, what if we had a snow-centric observing satellite mission in space?" Forman said.

Of supercomputers and satellites

"In order to do all this, you have to use supercomputers," Forman said. Specifically, the Discover Supercomputer at Goddard and Deepthought2 High-Performance Computing cluster at the University of Maryland.

Once the data from the different sensors are in the simulation tool, the team is able to run experiments that include different scenarios, such as putting a satellite into one orbit versus another, or having a satellite look at a wide swath versus narrow swath of Earth. With this suite of experiments, they can compare how well a certain combination performs compared to a benchmark scenario, Forman said.

As a general rule, with more satellites in orbit, scientists would have higher quality data, Forman said. However, "We can ask, what is the marginal gain if we had one more radiometer?" Forman said.

The new snow-sensing simulation tool will help create a space-based snow observation strategy to better understand this vital freshwater resource. The simulator will be used to "continue to ask questions of what should be next and how we should be planning in 20 years or more," Forman said.

This new snow simulation tool is funded by NASA's Earth Science Technology Office.

Strongyloides stercoralis is a soil-transmitted threadworm that is endemic in many tropical and subtropical areas of the world. Now, researchers reporting in PLOS Neglected Tropical Diseases have conducted a nation-wide parasitology survey of the Cambodian population and concluded that nearly a third of the studied population is infected with S. stercoralis.

The threadworm is transmitted through infected larvae in the soil and, like hookworms, infect humans through the skin. The worm can cause long-lasting and potentially fatal infections in people. Larvae are not detected by standard coprological diagnostics, so S. stercoralis has been under-detected and overlooked for decades. However, previous surveys in individual provinces of Cambodia have found high prevalence rates of the infection.

In the new work, Peter Odermatt, of the Swiss Tropical and Public Health Institute, and colleagues used a diagnostic test that detects S. stercoralis IgG antibodies in the urine. 7,246 enrolled study participants took the test and provided data on demography, hygiene, and knowledge about helminth infection.

Overall, 30.5% of participants were infected with threadworms. The rate in individual provinces ranged from 10.9% to 48.2%, with prevalence rates below 20% in only five south-eastern provinces. The risk of infection increased with age, and open defecation was associated with a higher risk while knowledge about helminth infections lowered a person's risk. In addition, S. stercoralis infection was positively associated with night temperatures, rainfall and distance to water, and negatively associated with land occupied by rice fields. Advanced spatial statistical modeling allowed predicting S. stercoralis in unsurveyed locations, which lead to a unique result, namely a country-wide risk profile for S. stercoralis infection in Cambodia.

"Our study represents a clear risk map of S. stercoralis of a highly endemic setting," the researchers say. "Based on these data the population at risk can be quantified and planning of concrete control approach become realistic." Subsidies to support the high cost of drugs, or affordable generics, are needed to start tackling the worm, they add.

UPTON, NY--Scientists studying plant biochemistry at the U.S. Department of Energy's Brookhaven National Laboratory recently made a surprising discovery: They found that a protein that turns on oil synthesis also activates a protein that puts the brakes on the same process. In a paper just published in the journal Plant Physiology, they describe how this seemingly paradoxical system keeps oil precursors perfectly balanced to meet plants' needs.

"We were initially surprised by our discovery that the signaling protein that turns on the oil synthesis pathway also turns on the off switch," said Brookhaven Lab biochemist John Shanklin, who led the research.

But after further investigation it made perfect sense. Fatty acids--the precursors to oils--can be toxic if allowed to accumulate. If the levels increase beyond the cell's requirements for making lipid components of membranes or oils, the cells need a way to shut production off.

The key is that the off switch, a protein known as BADC, is a "conditional inhibitor," Shanklin said. It only puts on the brakes when the level of free fatty acids is high.

This work could advance the team's efforts to find new ways to control oil production in plants with the goal of making fuels or other useful products.

Putting the pieces together

The new study builds on previous work by Shanklin's group. One of those studies [https://www.bnl.gov/newsroom/news.php?a=112829] revealed that BADC exerts its braking mechanism by inserting itself into a key enzyme involved in making fatty acids, ACCase.

"We were interested to learn more about the BADC proteins, and how the genes for these proteins were regulated," Shanklin said.

In another study [https://www.bnl.gov/newsroom/news.php?a=113109], the team had explored details of the signaling protein known as WRINKLED1, which turns on the enzymes for fatty acid synthesis, including parts of ACCase, and therefore serves as the on switch for the oil-synthesis pathway.

The scientists had little reason to suspect a direct connection between WRI1 (the on switch) and BADC (the off switch) until the lead authors, Hui Liu and Zhiyang Zhai, observed that plants with mutations in genes for either protein had unusually short roots.

"It would have been easy to overlook this connection as a coincidence, but Liu and Zhai's observation turned out to be central to the mechanism we discovered," Shanklin said.

Further investigation showed that the aberrant hormone levels seen in WRI1 mutant roots were like those found in roots of the BADC mutant. Closer biochemical-genetic investigations led the team to conclude that both proteins were indeed linked to this growth defect--which triggered them to explore the connection further.

Working with Brookhaven colleague Jorg Schwender, they showed that the WRI1 on switch bound tightly to the BADC gene, enabling it to be turned on. They confirmed the connection by showing that adding more BADC to the WRI1 mutant made the roots grow longer.

The key point is that having the on switch turn on genes for the off switch doesn't necessarily turn fatty acid synthesis off. It just gives the cell a way to turn synthesis off if fatty acid levels get too high. And the more WRI1 ramps up fatty acid production, the more the cell also needs to ramp up BADC to be able to stop that process.

"It's like giving a faster car the bigger brakes it would need to stop if a deer runs into the road," Shanklin said.

"Making lots of membranes or oil will keep fatty acid levels low, and the BADC braking system won't be needed," Shanklin explained. "It's only when production exceeds demand and fatty acids build up that the brakes need to be applied."

The scientists are now conducting further biochemical studies to explore how elevated free fatty acids trigger BADC to become inserted into ACCase to put the brakes on.

TORONTO, June 20, 2019 - There is no statistical evidence that global cigarette consumption has fallen as a result of the World Health Organization's Framework Convention on Tobacco Control, and in low- and middle-income countries it has actually increased, according to two studies led by global health researchers at York University.

The studies, published in The British Medical Journal (BMJ), put into question the widely held belief that the FCTC has been the most successful health treaty ever created. An international treaty adopted in 2003 to reduce harmful tobacco consumption, the FCTC's effects on cigarette consumption had never been scientifically studied on a global level. The research also puts the spotlight on the urgent need not only for investment in tobacco control practices but also an evaluation of the effectiveness of this international law and reporting practices.

"The policies promoted by this treaty - plain packaging, smoke-free areas, tobacco taxes - have been monolithically proven to be effective," says Steven Hoffman, professor in the Dahdaleh Institute for Global Health Research, Faculty of Health, and Osgoode Hall Law School, who is lead author of the studies. "What this study shows is that it's probably not enough at the global level to recognize these policies as important or to formally adopt them. We need countries to implement them to make sure they're affecting people's lives around the world. If not, what's at stake, according to the WHO, is one billion people around the world might die from tobacco consumption in the 21st century."

In the first study, Hoffman and co-author Mathieu Poirier, assistant professor, York University's Faculty of Health, analyzed data collected from 71 countries, representing 95 percent of the world's tobacco consumption and over 80 percent of the world's population between the years of 1970 and 2015. The data collection is the largest appraisal and selection of comparable national estimates of tobacco consumption done to date, in an effort to better understand international cigarette consumption trends since 1970. Researchers found that cigarette consumption fell in most countries, however consumption trends varied from country to country, especially in lower-income countries.

The open-access dataset looked at sales, production, imports, and exports, with up to six different sources compiled for each country per year. Researchers found a general decline in per capita cigarette consumption beginning around 1985 in five of the top ten cigarette-consuming countries: United States, Japan, Poland, Brazil, and Germany. The United States, Canada, and Australia all demonstrated similar continuous declines in consumption since the early 1980s, while Latin American and Caribbean countries experienced more modest declines. In contrast, per capita consumption rose steadily in China and Indonesia. China was found to be the world's leading consumer of cigarettes, with over 2.5 million metric tonnes consumed in 2013 - more than the next 40 highest consuming countries combined.

In the second study, Hoffman and his team used the data from the first study and looked at it in the context of the Framework Convention on Tobacco Control which has been ratified by 181 countries since its adoption in 2003. This gave researchers a clear intervention point on tobacco consumption for the study. The study used two quasi-experimental methods, the first using interrupted time-series analysis (ITS) and the second using in-sample forecast event modelling. The data showed no significant change in the rate at which global cigarette consumption had been decreasing after adoption of the treaty.

"This study sets a new gold standard for how to evaluate international laws," said co-author Poirier. "The FCTC was widely celebrated at the time it was launched and no one has actually evaluated that treaty on a global level until now."

The research showed that after 2003, high income and European countries experienced a decrease in annual consumption by more than 1,000 cigarettes per adult, while low- and middle-income and Asian countries showed an increase of more than 500 cigarettes annually per adult.

Researchers suggest that varied implementation of tobacco control policies and shifting trends in cigarette affordability across countries may have generated market equilibrium effects that incentivized the tobacco industry to move its lobbying, marketing and promotion activities away from countries with strict guidelines and toward countries with less stringent measures.

"We found quantitative evidence that could support that idea: that tobacco companies, after the Framework Convention on Tobacco Control, specifically went to jurisdictions that were not implementing proven tobacco control policies as rapidly as we saw in high income countries," said Hoffman. "If this is true, this means the FCTC could even have unintentionally caused harm by encouraging tobacco companies to target the many more people who live in these areas and Asian countries who would have fewer governmental protections against the companies' efforts."

If the climate continues warming as predicted, spruce beetle outbreaks in the Rocky Mountains could become more frequent, a new multi-year study led by Colorado State University finds.

While insect disturbances naturally cycle through forests, the current spruce beetle epidemic affecting Colorado Engelmann spruce forests has been one of the largest on record. The Colorado State Forest Service estimates that since 1996, over 40 percent of the state's high-elevation forests, encompassing an area larger than Delaware and Rhode Island combined, have already been affected by this latest cycle. According to the research team, this has resulted in a widespread die-off of trees valued for their contributions to clean water, recreation and wood products.

The study, recently published in Environmental Entomology, provides new clues about spruce beetle behavior. Study co-authors Seth Davis, assistant professor in CSU's Forest and Rangeland Stewardship department, and Isaac Dell, a graduate student at Montana State University, combined new beetle population and environmental data with climate projection models to see what could be in store in the future.

"Unfortunately, what we found suggests there is no best-case scenario," said Davis, a specialist in plant and insect interactions. "Even if the climate increases by just one degree Celsius, we can expect spruce beetles to reproduce at higher rates than we've seen, with more time to invade trees."

Their results indicate slightly warmer conditions could contribute to longer flight periods and more eruptive beetle populations, due to larger populations of fertile females. This combination could equate to more intense insect pressure on spruce forests.

Temperature plays a critical role in this species' lifecycle by affecting the insect's development, dispersal and flight patterns. At field sites that spanned the length of Colorado, Dell collected hourly temperature data along with more than 70,000 insects across the 2017 and 2018 growing seasons. With corresponding winter temperature data from the PRISM Climate Group at Oregon State University, some patterns emerged.

"It became apparent that beetles in 2018 were larger in size, after a warmer and drier winter than in the previous year, and that females were also more numerous," said Dell, who recently graduated from CSU with a master's degree in Forest Sciences.

By adding one degree Celsius to the daily temperature data set, climate projections showed a likely increase of 200 growing degree-days, which are used to predict plant and animal development, at these locations. This projection is based on the assumption that new global greenhouse gas production would be eliminated by 2020. According to the researchers, this could extend the beetle's potential flight period from a few weeks to multiple months.

The study found that the insects' flights would also become more varied, making coordinated beetle attacks harder to predict.

To monitor these populations and subsequent impacts on Engelmann spruce trees, Dell said management efforts need to consider this expanded time period.

"For monitoring efforts, the best course of action for people is to place traps out earlier in the season," added Dell. "We also recommend removing infested trees and traps in August, at the end of the beetle flight period."

Davis said that while this scenario isn't good news, he remains an optimist. By his estimates and through personal observation, up to 30 percent of beetle-infested, high-elevation forests have survived.

"It's not always as bad as it looks when you're driving by," he said. "These interactions have been happening for thousands of years, and life, whether it's a beetle, a tree or a forest, seems to find a way."

New Rochelle, NY, June 19, 2019-Surfaces that enable endothelial cell attachment without causing blood clotting are needed for various tissue engineering efforts. A new approach involving phage display has been used to identify unique peptides with these typically divergent characteristics. The work is published in Tissue Engineering, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. Click here to read it for free through July 20, 2019.

Maria Chiara Munisso, PhD, and Tetsuji Yamaoka, PhD, both at the National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan, present their work in an article titled "Evolution of Phage Display Approaches to Select Highly Specific Hemocompatible Peptides". The authors developed a high-throughput phage display selection protocol to identify peptides with high affinity for endothelial cells using both positive selection and an extra negative selection against platelet-binding sequences, and a phage binding index was used to compare affinities to those of naked M13 phage. After modification with candidate peptides, an expanded polytetrafluoroethylene surface was tested for endothelial progenitor cell binding and clotting induction, and a sequence with desirable dual characteristics was validated.

"The use of Negative-Positive bio-panning with the techniques proposed by the authors demonstrates a clear improvement in strategies to identify peptides for biofunctionalization," says Tissue Engineering Co-Editor-in-Chief Antonios G. Mikos, PhD, Louis Calder Professor at Rice University, Houston, TX. "This can dramatically improve the search for new biofunctional peptides which can be used across all facets of tissue engineering and medical devices."

On June 22, 1969, the Cuyahoga River, which flows through Cleveland, Ohio, caught fire. Although firefighters extinguished the blaze within 30 minutes, the shocking event helped galvanize the U.S. environmental movement. Fifty years later, the river is much healthier but still recuperating from a legacy of pollution, according to an article in Chemical & Engineering News (C&EN), the weekly newsmagazine of the American Chemical Society.

In the late 1960s, the Cuyahoga River passed through a heavily industrialized area of Cleveland that included steel mills, manufacturing plants and a paint factory. Back then, industrial facilities discharged tens of millions of gallons of wastewater and sewage directly into the river each day. The 1969 fire was likely caused by sparks from a train passing over a bridge, which ignited oily debris on the water. Although this wasn't the first time the river had caught fire, it would be the last, Senior Correspondent Cheryl Hogue writes.

In part because of public outcry about Cuyahoga and other polluted sites, President Richard Nixon formed the Environmental Protection Agency in 1970, and Congress passed the Clean Water Act in 1972. As a result, companies now pretreat their industrial wastewater to remove pollutants and then pump the water into the public sewage system. In addition, improvements have been made to the wastewater treatment infrastructure in Ohio and elsewhere. Although the Cuyahoga is now showing signs of improvement, it will still take a while for the river to fully recover, experts say.

Scientific inquiry often begins with the "why."

Without expecting to do more than answer a question posed by a YouTube video, Virginia Tech researchers may have changed how people think about the process of freezing.

VIDEO: https://youtu.be/ICo5z1fsV34

Lead Virginia Tech researcher Jonathan Boreyko, an assistant professor in mechanical engineering in the College of Engineering, and his student researchers were watching a YouTube video of a soap bubble freezing. The mesmerizing sight of ice crystals floating around the bubble made the engineers wonder what caused the phenomenon.

Boreyko and student researchers Farzad Ahmadi and Saurabh Nath, both graduate students in engineering mechanics, and Christian Kingett, an undergraduate researcher in engineering science and mechanics who graduated in 2019, conducted literature research and found that no one had ever studied how soap films or bubbles freeze.

The results of the team's query, which began as a simple "why," has been published in the journal Nature Communications, explaining the physics behind what causes the ice crystals jump up into the bubble and swirl around, thus changing perceptions about the process of freezing.

"We started by freezing a bubble in the lab, using a frozen substrate," Boreyko explained. "What we found was that the bubble would freeze from the bottom to a certain point and then stop. We didn't get that lovely 'snow globe effect' that we saw on the video. But, Farzad made a nice model that can accurately predict where the freeze front will stop based on the size of the bubble and the air temperature."

Because the shell of a bubble is microscopically thin, the warm air temperature in the lab prevented the cold stage from completely freezing the bubble. Moving to a walk-in freezer, the team tried the experiment again, believing they would discover how the floating ice crystals were formed.

"We didn't see it in the freezer, either, at first," Boreyko said. "But we tried again depositing the bubble on ice instead of a dry substrate, and that is where we saw what we were looking for."

At minus 20 degrees Celsius and using an ice substrate, the bubble quickly filled with floating crystals that hastened the complete freezing of the bubble, and opened the researcher's eyes.

"When you deposit the bubble on an icy substrate, the bubble begins to freeze, which releases heat," said Ahmadi. "The bottom of the bubble, in this case, becomes warmer than the rest of the bubble - it's freezing-induced heating."

The molecular energy releases when the water molecules fuse together into a tight-packed solid lattice created a temperature difference of about 14 degrees - minus 20 at the top of the bubble and minus 6 degrees at the frozen base.

"The temperature gradient from top to bottom changed the surface tension," Ahmadi said. "The tension created a flow from the hot toward the cold."

This flow is known as Marangoni Flow. When it occurs in the freezing bubbles, the flow rips ice crystals from the bottom of the bubble and swirls them around the liquid shell where they enlarge until the entire bubble is frozen.

"Previously we thought that how fast we could freeze something depended on how fast the freeze front could grow," Boreyko said. "This shows us that a freezing-induced Maragoni Flow will create hundreds of additional freeze fronts from the ice crystals removed from the bottom. So, we realized it's not just how fast one front grows, but in cases like our bubble, you can manipulate the system to have hundreds of freeze fronts working together to freeze something much faster."