A better way to separate gases

A new membrane material, pictured here, could make purification of gases significantly more efficient, potentially helping to reduce carbon emissions.
Credits: Courtesy of the researchers

Industrial processes for chemical separations, including natural gas purification and the production of oxygen and nitrogen for medical or industrial uses, are collectively responsible for about 15 percent of the world’s energy use. They also contribute a corresponding amount to the world’s greenhouse gas emissions. Now, researchers at MIT and Stanford University have developed a new kind of membrane for carrying out these separation processes with roughly 1/10 the energy use and emissions.

Using membranes for separation of chemicals is known to be much more efficient than processes such as distillation or absorption, but there has always been a tradeoff between permeability — how fast gases can penetrate through the material — and selectivity — the ability to let the desired molecules pass through while blocking all others. The new family of membrane materials, based on “hydrocarbon ladder” polymers, overcomes that tradeoff, providing both high permeability and extremely good selectivity, the researchers say.

The findings are reported in the journal Science, in a paper by Yan Xia, an associate professor of chemistry at Stanford; Zachary Smith, an assistant professor of chemical engineering at MIT; Ingo Pinnau, a professor at King Abdullah University of Science and Technology, and five others.

Red-backed salamanders possess only limited ability to adjust to warming climate

To stay cool and not burn energy, salamanders have evolved strategies such as burrowing under rocks and logs. But if they are hiding to stay cool for much longer periods, they are not foraging and eating, and at the end of a long summer their condition deteriorates.
Credit: David Munoz

If average temperatures rise as projected in eastern North America in coming decades, at least one widespread amphibian species likely will be unable to adjust, and its range may shift northward, according to a new study led by Penn State scientists.

In a novel experiment, researchers devised a method to measure the metabolic rate of red-backed salamanders from different regions exposed to warmer temperatures — analyzing how much more energy the small, hardy woodland amphibians would expend to survive in the forests they now inhabit from Quebec south to North Carolina, and west to Missouri and Minnesota.

To stay cool and not burn energy, salamanders have evolved strategies such as burrowing under rocks and logs, explained study co-author David Miller, associate professor of wildlife population ecology. But if they are hiding to stay cool for much longer periods, they are not foraging and eating, and at the end of a long summer their condition deteriorates.

Quantum Physics Sets a Speed Limit to Electronics

An ultra-short laser pulse (blue) creates free charge carriers, another pulse (red) accelerates them in opposite directions.
Credit: Vienna University of Technology

Semiconductor electronics is getting faster and faster - but at some point, physics no longer permits any increase. The shortest possible time scale of optoelectronic phenomena has now been investigated.

How fast can electronics be? When computer chips work with ever shorter signals and time intervals, at some point they come up against physical limits. The quantum-mechanical processes that enable the generation of electric current in a semiconductor material take a certain amount of time. This puts a limit to the speed of signal generation and signal transmission.

TU Wien (Vienna), TU Graz and the Max Planck Institute of Quantum Optics in Garching have now been able to explore these limits: The speed can definitely not be increased beyond one petahertz (one million gigahertz), even if the material is excited in an optimal way with laser pulses. This result has now been published in the scientific journal "Nature Communications".

Researchers first to sample permafrost CO2 emissions during fall and winter

A soil sampling device used by Claudia Czimczik (left), UCI professor of Earth system science, and Shawn Pedron, UCI post-doctoral scholar in Earth system science, enabled the researchers to study permafrost at various depths to measure CO2 emissions from Arctic tundra permafrost. The photo was taken at the NSF Toolkit Field Station in Alaska in August 2019.
Credit: Claudia Czimzcik / UCI

The Arctic is warming along with the rest of the planet, and as this is happening, its permafrost – perennially frozen arctic soil that holds a lot of trapped organic matter from dead plants – is thawing. As the permafrost thaws, the organic matter it holds is thawing, too, and this is opening the door for microorganisms to decompose that matter and, in the process, release climate-warming greenhouse gases like carbon dioxide and methane into the atmosphere.

In new research published on today in the journal Geophysical Research Letters, a team led by scientists at the University of California, Irvine report for the first-time direct measurements of the gases emitted from permafrost during the fall and winter months – measurements that can help fill in gaps in permafrost emissions estimates that climate scientists have until now missed.

“It’s the first time we are able to look at the carbon sources that fuel carbon emissions during the fall and winter periods,” said Claudia Czimczik, a professor of Earth system scientist at UCI who’s the senior author of the new study.

Researchers discover new tools in regular blood samples for developing precision therapies for lymphoma

Image: Leppä lab

In a recently completed study, researchers from the University of Helsinki and Helsinki University Hospital Comprehensive Cancer Center investigated the characteristics and clinical significance of circulating tumor DNA (ctDNA) found in the blood of patients with aggressive lymphoma. The study was carried out through Nordic collaboration.

Analyzed in the study were blood samples of lymphoma patients treated in a Nordic Lymphoma Group trial, which were collected before, at the mid-point of and after treatment.

Increasingly accurate diagnostics and more effective therapies

“The analysis of ctDNA in the blood samples revealed significant diagnostic features, not all of which were found in regular tumour biopsies,” says Professor Sirpa Leppä from the University of Helsinki and the HUS Comprehensive Cancer Center.

The researchers found that the concentration of ctDNA in blood before therapy varied considerably between patients and was comparable to the combined volume of the malignant tumors.

“Patients with the highest ctDNA levels at the time of lymphoma diagnosis had the poorest survival probability,” explains MD and PhD student Leo Meriranta.

At the same time, changes in ctDNA concentration during therapy reflected treatment responses in that the patients whose lymphoma was unaffected by the treatment were distinguished from other patients by the ctDNA analyses carried out using the follow-up blood samples.

Ultraviolet Light Can Clean N95 Masks for Reuse Without Hindering Performance

The N95 mask owes its remarkable filtering ability to its three-layer structure. While the fibers in the outer- and innermost layers block large particles such as water droplets, the middle is where much finer, charged fibers electrically attract and trap tiny, submicron aerosols.
Credits: SEM images by A. Vladar/NIST, animation by J. Wang/NIST

To combat COVID-19 amid supply shortages in 2020, health care facilities across the U.S. resorted to disinfecting personal protective equipment (PPE), such as N95 masks, for reuse with methods such as ultraviolet (UV) light. But questions lingered about the safety and efficacy of these methods and how best to implement them. 

Now, in perhaps the most rigorous examination of UV light’s effects on N95 masks yet, researchers at the National Institute of Standards and Technology (NIST) have shown that these masks can be disinfected with little impact on their form or function. In a new study published in the Journal of Research of the National Institute of Standards and Technology, the researchers, with help from federal and private partners, scrutinized UV-exposed N95 masks for traces of virus and looked for changes in the shape of their fibers, ability to filter out aerosols and other properties. 

The results represent a key step toward devising UV standards that could have far-reaching benefits in the future.

Enhancing the electromechanical behavior of a flexible polymer

Qiming Zhang, distinguished professor of electrical engineering, led a team of researchers to develop a robust piezoelectric material that can convert mechanical stress into electricity.
Credit: Tyler Henderson/Penn State

Piezoelectric materials convert mechanical stress into electricity, or vice versa, and can be useful in sensors, actuators and many other applications. But implementing piezoelectrics in polymers — materials composed of molecular chains and commonly used in plastics, drugs and more — can be difficult, according to Qiming Zhang, distinguished professor of electrical engineering.

Zhang and a Penn State-led team of interdisciplinary researchers developed a polymer with robust piezoelectric effectiveness, resulting in 60% more efficient electricity generation than previous iterations. They published their results today (Mar. 25) in Science. 

“Historically, the electromechanics coupling of polymers has been very low,” Zhang said. “We set out to improve this because the relative softness of polymers makes them excellent candidates for soft sensors and actuators in a variety of areas, including biosensing, sonar, artificial muscles and more.”

To create the material, the researchers deliberately implemented chemical impurities into the polymer. This process, known as doping, allows researchers to tune the properties of a material to generate desirable effects — provided they integrate the correct number of impurities. Adding too little of a dopant could prevent the desired effect from initiating, while adding too much could introduce unwanted traits that hamper the material’s function.  

Breakthrough application of moisture-trapping film

 

The team comprises Asst Prof Tan Swee Ching (front right), doctoral student Ms Yang Jiachen (third from right) and researchers from HTX.
Credit: National University of Singapore

A team of researchers from the National University of Singapore (NUS) has developed a novel super-hygroscopic material that enhances sweat evaporation within a personal protective suit, to create a cooling effect for better thermal comfort for users such as healthcare workers and other frontline officers. This invention was validated through laboratory tests conducted in collaboration with researchers from HTX (Home Team Science & Technology Agency) in Singapore.

The new desiccant film, which is biocompatible and non-toxic, has a fast absorption rate, high absorption capacity and excellent mechanical properties. This means that the material is very robust and durable for practical applications such as for protective suits worn by healthcare workers. It is also affordable, light-weight, easy to fabricate and reusable.

“Under room temperature of about 35 deg. C, a healthcare worker who doesn't wear a protective suit for one hour typically experiences a heat index of about 64 deg. C. This causes discomfort and prolong thermal strain can result in heat stroke and even death. Our novel composite moisture-trapping film achieves a cooling effect within the protective suit via evaporative cooling – by increasing sweat evaporation from the skin,” explained research team leader Assistant Professor Tan Swee Ching, who is from the Department of Materials Science and Engineering under the NUS College of Design and Engineering.

Molecular key may unlock new treatments for neurodegenerative disorders

Structure of SARM1 in complex with inhibitor.
Credit: Thomas Ve

Researchers have worked out how to successfully switch off a key pathway of nerve fiber breakdown in debilitating neurodegenerative disorders such as Parkinson’s disease, traumatic brain injury and glaucoma.

The study, led by Griffith University’s Institute for Glycomics and Disarm® Therapeutics, a wholly owned subsidiary of pharmaceutical company Eli Lilly, reveals the structural processes behind activation and inhibition of SARM1, a key molecule in the destruction of nerve fibers.

“As a trigger for nerve fiber degeneration, understanding how the enzyme SARM1 works may help us treat several neurodegenerative conditions,” said Dr Thomas Ve from the Institute for Glycomics.

“In this study we show the molecular interactions that can switch SARM1 on and off. This gives us a clear avenue for the design of new drug therapeutics.”

In neurodegenerative conditions like peripheral neuropathy, Parkinson’s disease, amyotrophic lateral sclerosis (ALS), traumatic brain injury and glaucoma, when the nerve fibers are damaged, SARM1 is activated.

“This sparks a cascade of molecular processes that leads to the self-destruction of the nerve cell’s axon, the cable that carries electric impulse away from the body of the nerve cell to the next,’’ Dr Ve said.

Missing buil­ding block for quan­tum optimi­zation develo­ped

From left to right: Kilian Ender, Clemens Dlaska, Wolfgang Lechner, Rick van Bijnen, Andreas Kruckenhauser, Glen Bigan Mbeng
Credit: Uni Innsbruck

Optimization challenges in logistics or finance are among the first possible applications of quantum machines. Physicists from Innsbruck, Austria, have now developed a method that enables optimization problems to be investigated on quantum hardware that already exists today. For this purpose, they have developed a special quantum gate.

The development of quantum computers is being pursued worldwide, and there are various concepts of how computing using the properties of the quantum world can be implemented. Many of these have already advanced experimentally into areas that can no longer be emulated on classical computers. But the technologies have not yet reached the point where they can be used to solve larger computational problems. Therefore, researchers are currently looking for applications that can be implemented on existing platforms. "We are looking for tasks that we can compute on existing hardware," says Rick van Bijnen of the Institute of Quantum Optics and Quantum Information at the Austrian Academy of Sciences in Innsbruck. A team around Van Bijnen and the Lechner research group is now proposing a method to solve optimization problems using neutral atoms.