A new study published in Nature Communications by scientists at WCS, the University of California, Berkeley, and the United States Forest Service shows that nearly 60 percent of all mountainous area is under intense human pressure. Most of the pressure is at low elevations and mountain bases, which tend to be easier places for people to live, grow food, and build roads. The scientists then used climate models to make predictions about how species would move under climate change. Based on their predictions, they found that species tend to move to higher elevations, and that these higher elevations tend to have more intact land for species because there is less human pressure.

Without factoring in human pressure, the authors warn that conservation actions may be misguided. Factoring in human pressure reveals the true ‘shape’ of a mountain for species that are restricted to intact landscapes, which are often the species of greatest conservation concern. Here, the ‘true shape’ refers to how much land area is potentially available as habitat for a species as it moves up in elevation, not simply how much total land area is available. The true shape can reveal where species will tend to lose versus gain intact land area as they shift under climate change: the elevations where species are expected to lose area represent the priority zones for conservation.

Mountains are home to over 85 percent of the world’s amphibians, birds, and mammals, making them global conservation priorities. But mountain-dwelling species are at risk from human activities, such as agriculture, livestock grazing, and development that reduce their habitat, and climate change that threatens to push species upslope as they struggle to find tolerable temperatures.

“Species are adapted to certain temperature conditions. As temperatures warm in mountains, scientists have documented species moving to higher elevations to maintain the same temperatures,” said Paul Elsen, a WCS Climate Adaptation Scientist and lead author of the study. “This was always seen as a problem, because species would have less land area and less habitat to occupy at high elevations. But what we found is that as species move upslope, they tend to move away from areas that are already under intense human pressure and into areas with reduced human pressure. As a result, they can occupy more intact land area, even if the total amount of land area declines.”

The authors combined several global databases to make their assessments: high-resolution digital elevation models gave a picture about how much surface area is available at different elevations. The Human Footprint Index provided information on pressure from human activities. Global climate models projected how temperatures are likely to change by the late 21st century.

The authors then used computer simulations to place hundreds of thousands of hypothetical ‘species’ across all mountain ranges at different elevations and then predicted how they would shift their ranges based on climate projections. For each simulation, they compared the amount of area the species had to begin with to the amount they would have after the range shift under climate change.

Said Elsen: “We were surprised to find that many species had more intact land area available after the range shift compared to when they started.”

The results suggest that many species in mountain ranges may have more intact land area available in the future if they track warming temperatures to higher slopes, though there were exceptions.

“Our results offer a glimmer of hope for montane species under climate change,” Elsen said. “Montane species are still facing tremendous human pressure, especially at low elevations, but we have the opportunity now to protect intact habitats at higher elevations to give these species the best possible chance going forward.”

Story Source:

Materials provided by Wildlife Conservation Society. Note: Content may be edited for style and length.

The study was published April 21 in the journal Science Signaling.

Senior author Madesh Muniswamy, Ph.D., from the Long School of Medicine at The University of Texas Health Science Center at San Antonio, is an expert in the function and properties of mitochondria. These are the cell structures that convert sugar and fat into chemical energy called ATP.

“We want to offer, in the future, a solution to the metabolic crisis faced by millions of people across the world,” Dr. Muniswamy said. “Millions of people consume too much food, while millions of others are in poverty and subsist on too little food. We are studying what happens at the molecular level in both situations with a goal of developing a drug to intervene.”

Speed of conversion

Our bodies continuously move things from cell to cell with what are sort of like roadways and cars. The vehicle required for fat and sugar conversion is called the mitochondrial calcium uniporter, or MCU. Like traffic moving people to destinations, the speed at which the MCU moves the energy is essential. If it is too slow, conditions such as obesity appear. If it is too fast, malnourishment results.

Driving a regulated speed limit at all times is desirable for proper health, Dr. Muniswamy said.

Keeper of the road

In the Science Signaling article, Dr. Muniswamy and colleagues describe another key component that, like a traffic police officer, regulates this roadway activity.

“We identified a mitochondrial protein called MICU1 that functions as a gatekeeper of this roadway,” Dr. Muniswamy said.

When nutrient levels are low, MICU1 clamps down on the channel activity to prevent excess energy transaction. “When you’re starving, you want to live longer, you don’t want to burn all the sugar and the fat you have, so MICU1 slows down the activity,” Dr. Muniswamy said.

The opposite is also true — if the roadway traffic is driving too slowly, MICU1 can rev it up.

Relieve conditions

“In the future, we might design a new drug to control this pathway to basically alleviate many cardiovascular- and metabolic syndrome-related diseases,” Dr. Muniswamy said. “That’s our plan.

“When you speed up the channel, all the sugar and fat will be burned, and you slim down,” he added.

Acknowledgments

The research involves multiple faculty and staff of the Department of Medicine and the Center for Renal Precision Medicine, both within the Long School of Medicine at UT Health San Antonio. Collaborators are from the Lewis Katz School of Medicine at Temple University, the Penn State University College of Medicine and Cedars-Sinai Medical Center in Los Angeles.

Coauthors in the Long School of Medicine are W. Brian Reeves, M.D.; Kumar Sharma, M.D.; Luke Norton, Ph.D.; Subramanya Srikantan, Ph.D.; Madesh Muniswamy, Ph.D.; Cassidy C. Daw; Travis R. Madaris; Karthik Ramachandran, Ph.D.; Benjamin T. Enslow; Cherubina S. Rubannelsonkumar; Soumya Maity, Ph.D.; Pragya SinghMalla; and Christopher E. Shannon, Ph.D. Dr. Muniswamy is the corresponding author. Coauthor from the School of Dentistry at UT Health San Antonio is Brij B. Singh, Ph.D.

Funding is from the National Institutes of Health and U.S. Department of Defense.

In collaboration with Jennifer N. Gelinas, Department of Neurology, and the Institute for Genomic Medicine at Columbia University Iriving Medical Center, Khodagholy has recently published two papers, the first in Nature Materials (March 16) on ion-driven soft and organic transistors that he and Gelinas have designed to record individual neurons and perform real-time computation that could facilitate diagnosis and monitoring of neurological disease.

The second paper, published today in Science Advances, demonstrates a soft, biocompatible smart composite — an organic mixed-conducting particulate material (MCP) — that enables the creation of complex electronic components which traditionally require several layers and materials. It also enables easy and effective electronic bonding between soft materials, biological tissue, and rigid electronics. Because it is fully biocompatible and has controllable electronic properties, MCP can non-invasively record muscle action potentials from the surface of arm and, in collaboration with Sameer Sheth and Ashwin Viswanathan at Baylor College of Medicine’s department of neurosurgery, large-scale brain activity during neurosurgical procedures to implant deep brain stimulation electrodes.

“Instead of having large implants encapsulated in thick metal boxes to protect the body and electronics from each other, such as those used in pacemakers, and cochlear and brain implants, we could do so much more if our devices were smaller, flexible, and inherently compatible with our body environment,” says Khodagholy, who directs the Translational NeuroElectronics Lab at Columbia Engineering. “Over the past several years, my group has been working to use unique properties of materials to develop novel electronic devices that allow efficient interaction with biological substrates — specifically neural networks and the brain.”

Conventional transistors are made out of silicon, so they cannot function in the presence of ions and water, and in fact break down because of ion diffusion into the device. Therefore, the devices need to be fully encapsulated in the body, usually in metal or plastic. Moreover, although they work well with electrons, they are not very effective at interacting with ionic signals, which is how the body’s cells communicate. As a result, these properties restrict the abiotic/biotic coupling to capacitive interactions only on the surface of material, resulting in lower performance. Organic materials have been used to overcome these limitations as they are inherently flexible, but the electrical performance of these devices was not sufficient to perform real-time brain signal recording and processing.

Khodagholy’s team took advantage of both the electronic and the ionic conduction of organic materials to create ion driven transistors they call e-IGTs, or enhancement-mode, internal ion-gated organic electrochemical transistors, that have embedded mobile ions inside their channels. Because the ions do not need to travel long distances to participate in the channel switching process, they can be switched on and off quickly and efficiently. The transient responses depend on electron hole rather than ion mobility, and combine with high transconductance to result in a gain-bandwidth that is several orders of magnitude above that of other ion-based transistors.

The researchers used their e-IGTs to acquire a wide range of electrophysiological signals, such as in vivo recording of neural action impulses, and to create soft, biocompatible, long-term implantable neural processing units for the real-time detection of epileptic discharges.

“We’re excited about these findings,” says Gelinas. “We’ve shown that E-IGTs offer a safe, reliable, and high-performance building block for chronically implanted bioelectronics, and I am optimistic that these devices will enable us to safely expand how we use bioelectronic devices to address neurologic disease.”

Another major advance is demonstrated by the researchers in their Science Advances paper: enabling bioelectronic devices, specifically those implanted in the body for diagnostics or therapy, to interface effectively and safely with human tissue, while also making them capable of performing complex processing. Inspired by electrically active cells, similar to those in the brain that communicate with electrical pulses, the team created a single material capable of performing multiple, non-linear, dynamic electronic functions just by varying the size and density of its composite mixed-conducting particles.

“This innovation opens the door to a fundamentally different approach to electronic device design, mimicking biological networks and creating multifunctional circuits from purely biodegradable and biocompatible components,” says Khodagholy.

The researchers design and created mixed conducting particulate (MCP)-based high performance anisotropic films, independently addressable transistors, resistors, and diodes that are pattern-free, scalable, and biocompatible. These devices carried out a variety of functions, including recording neurophysiologic activity from individual neurons, performing circuit operations, and bonding high-resolution soft and rigid electronics.

“MCP substantially reduces the footprint of neural interface devices, permitting recording of high-quality neurophysiological data even when the amount of tissue exposed is very small, and thus decreases the risk of surgical complications,” says Gelinas. “And because MCP is composed of only biocompatible and commercially available materials, it will be much easier to translate into biomedical devices and medicine.”

Both the E-IGTs and MCP hold great promise as critical components of bioelectronics, from wearable miniaturized sensors to responsive neurostimulators. The E-IGTs can be manufactured in large quantities and are accessible to a broad range of fabrication processes. Similarly, MCP components are inexpensive and easily accessible to materils scientist and engineers. In combination, they form the foundation for fully implantable biocompatible devices that can be harnessed both to benefit health and to treat disease.

Khodagholy and Gelinas are now working on translating these components into functional long-term implantable devices that can record and modulate brain activity to help patients with neurological diseases such as epilepsy.

“Our ultimate goal is to create accessible bioelectronic devices that can improve peoples’ quality of life,” says Khodagholy, “and with these new materials and components, it feels like we have stepped closer to that.”

“Our lab previously proposed a technique for converting ethane into ethylene, and this new redox catalyst makes that technique more energy efficient and less expensive while reducing greenhouse gas emissions,” says Yunfei Gao, a postdoctoral scholar at NC State and lead author of a paper on the work. “Ethylene is an important feedstock for the plastics industry, among other uses, so this work could have a significant economic and environmental impact.”

“Ethane is a byproduct of shale gas production, and the improved efficiency of our new catalyst makes it feasible for energy extraction operations in remote locations to make better use of that ethane,” says Fanxing Li, corresponding author of the paper and an associate professor and University Faculty Scholar in NC State’s Department of Chemical Engineering.

“It is estimated that more than 200 million barrels of ethane are rejected each year in the lower 48 states due to the difficulty of transporting it from remote locations,” Li says. “With our catalyst and conversion technique, we think it would be cost effective to convert that ethane into ethylene. The ethylene could then be converted into liquid fuel, which is much easier to transport.

“The problem with current conversion techniques is that you can’t scale them down to a size that makes sense for remote energy extraction sites — but our system would work well in those locations.”

The new redox catalyst is a molten carbonate promoted mixed metal oxide, and the conversion process takes place at between 650 and 700 degrees Celsius with integrated ethane conversion and air separation. Current conversion techniques require temperatures higher than 800 degrees C.

“We estimate that the new redox catalyst and technique cut energy requirements by 60-87%,” Li says.

“Our technique would require an initial investment in the installation of new, modular chemical reactors, but the jump in efficiency and ability to convert stranded ethane would be significant,” Li says.

Story Source:

Materials provided by North Carolina State University. Note: Content may be edited for style and length.

Earthquakes happen when the rocks beneath the Earth’s surface break along geological fault lines and slide past each other. The properties of these faults — such as the roughness of their surface — can have an influence on the size of seismic events, however their study has been challenging because they are buried deep beneath the Earth’s surface.

In order to have a better understanding of the characteristics of these faults, researchers from McGill University, the University of California Santa Cruz and Ruhr University Bochum in Germany used high-resolution seismic reflection data to map and measure the roughness of 350 km2 of a plate boundary fault located off the Pacific coast of Costa Rica.

“We already knew that the roughness of a fault was an important factor, but we did not know how rough faults in the subsurface truly are, nor how variable the roughness is for a single fault,” says James Kirkpatrick, a professor in McGill’s Department of Earth and Planetary Sciences.

Rougher surfaces of faults may explain earthquake magnitude

In a recently published study in Nature Geoscience, Kirkpatrick and his colleagues were able to show that some parts of the studied fault have a rougher surface than others.

Historically, the earthquakes that have occurred in this part of the world have been moderately large (M7) and Kirkpatrick, who is also the study’s first author, believes the rough patches they found might be the reason why.

“These rough patches are stronger and more resistant to earthquake slip,” he says. “The historical record of earthquakes is relatively short, so we can’t say with certainty that larger ones have not occurred. Future seismic events in the area, which will be recorded with modern equipment, should help us determine if they show the same limited magnitude.”

Kirkpatrick and his colleagues also hope to apply their methods to other subduction zones where similar geophysical data is available to start to evaluate whether their conclusions are generally applicable.

“This connection between the fault roughness and earthquake magnitude might one day help us understand the size and style of earthquakes most likely to occur a given fault.”

Story Source:

Materials provided by McGill University. Note: Content may be edited for style and length.