. Scientific Frontline

Monday, November 28, 2022

New device can control light at unprecedented speeds

Scientists have developed a programmable, wireless spatial light modulator that can manipulate light at the wavelength scale with orders-of-magnitude faster response than existing devices.
Illustration Credit: Sampson Wilcox

In a scene from “Star Wars: Episode IV — A New Hope,” R2D2 projects a three-dimensional hologram of Princess Leia making a desperate plea for help. That scene, filmed more than 45 years ago, involved a bit of movie magic — even today, we don’t have the technology to create such realistic and dynamic holograms.

Generating a freestanding 3D hologram would require extremely precise and fast control of light beyond the capabilities of existing technologies, which are based on liquid crystals or micromirrors.

An international group of researchers, led by a team at MIT, spent more than four years tackling this problem of high-speed optical beam forming. They have now demonstrated a programmable, wireless device that can control light, such as by focusing a beam in a specific direction or manipulating the light’s intensity, and do it orders of magnitude more quickly than commercial devices.

They also pioneered a fabrication process that ensures the device quality remains near-perfect when it is manufactured at scale. This would make their device more feasible to implement in real-world settings.

Study finds that big rains bring big algae blooms… eventually

Center for Limnology system engineer Mark Gahler, right, co-author of a new study on the relationship between big storms and algae blooms, and colleague Jonathon Thom collect Lake Mendota data from instruments aboard David Buoy.
Photo Credit: Paul Schramm / University of Wisconsin–Madison

In the lake-rich regions of the world, algae blooms are a growing problem. Not only are the floating green scums a nuisance for anyone hoping to enjoy the water, they can turn toxic and threaten public health.

The main driver behind these blooms is phosphorus, an element used widely in agriculture to fertilize crops, that can run from the land and into lakes — especially during heavy rains. A new study from the University of Wisconsin–Madison shows how soon after a storm phosphorous “loading” sparks algae explosions, but also describes the many other factors that weigh on when and whether the lake reaches a tipping point.

“The fact that you just had a big storm doesn’t mean now you’re going to get a big [algae] bloom. The blooms are much more complicated.” says Steve Carpenter, lead author of a report published in the Proceedings of the National Academy of the Sciences.

Ancient Iowan super predator got big by front-loading its growth in its youth

Co-author Ben Otoo with a life-size illustration of Whatcheeria.
Photo Credit: Courtesy of Ben Otoo.

The Field Museum in Chicago is home to the best, most-complete fossils of a prehistoric superpredator-- but one that lived hundreds of millions of years before SUE the T. rex. Whatcheeria was a six-foot-long lake-dwelling creature with a salamander-like body and a long, narrow head; its fossils were discovered in a limestone quarry near the town of What Cheer, Iowa. There are around 350 Whatcheeria specimens, ranging from single bones to complete skeletons, that have been unearthed, and every last one of them resides in the Field Museum’s collections. In a new study in Communications Biology, these specimens helped reveal how Whatcheeria grew big enough to menace its fishy prey: instead of growing “slow and steady” the way that many modern reptiles and amphibians do, it grew rapidly in its youth.

“If you saw Whatcheeria in life, it would probably look like a big crocodile-shaped salamander, with a narrow head and lots of teeth,” says Ben Otoo, a co-author of the study and a PhD student at the University of Chicago and the Field Museum. “If it really curled up, probably to an uncomfortable extent, it could fit in your bathtub, but neither you nor it would want it to be there.”

Organizing nanoparticles into pinwheel shapes offers new twist on engineered materials

Jiahui Li, left, Shan Zhou and professor Qian Chen show off an electron micrograph image of their new pinwheel lattice structure developed to help engineers build new materials with unique optical, magnetic, electronic and catalytic properties. 
Photo Credit: Fred Zwicky

Researchers have developed a new strategy to help build materials with unique optical, magnetic, electronic and catalytic properties. These pinwheel-shaped structures self-assemble from nanoparticles and exhibit a characteristic called chirality – one of nature’s strategies to build complexity into structures at all scales, from molecules to galaxies.

Nature is rich with examples of chirality – DNA, organic molecules and even human hands. In general, chirality can be seen in objects that can have more than one spatial arrangement. For example, chirality in molecules might present itself as two strings of atoms that have the same composition, but each having a “twist” to the left or right in their spatial orientations, the researchers said.

The new study, led by Qian Chen, a professor of materials science and engineering at the University of Illinois Urbana-Champaign, and Nicholas A. Kotov, a professor chemical engineering at the University of Michigan, extends chirality into lattices assembled from nanoparticle building blocks to create new metamaterials – materials designed to interact with their surroundings to perform specific functions.

The study is published in the journal Nature.

Researchers build long-sought nanoparticle structure, opening door to special properties

Theoretical physicist Alex Travesset uses computer models, equations and scientific figures to explain how nanostructures assemble.
Photo Credit: Christopher Gannon/Iowa State University.

Alex Travesset doesn’t have a shiny research lab filled with the latest instruments that probe new nanomaterials and measure their special properties.

No, his theoretical work explaining what’s happening inside those new nanomaterials is all about computer models, equations and figures. And so, when he joins a project, the Iowa State University professor of physics and astronomy who’s also affiliated with the U.S. Department of Energy’s Ames National Laboratory might contribute many dense pages showing how nanoparticles assemble.

Case in point: Travesset’s “Chiral Tetrahedra” calculations and illustrations that are part of a research paper just published by the journal Nature. Those calculations show how controlled evaporation of a solution containing tetrahedron-shaped gold nanoparticles on a solid silicon substrate can assemble into a pinwheel-shaped, two-layered structure.

It turns out the nanostructure is chiral, meaning it’s not identical to its mirror image. (The classic example is a hand and its reflection. The thumbs end up on opposite sides and so one hand can’t be superimposed on the other. That’s chirality.)

Positive media coverage of cannabis studies regardless of therapeutic effect

Photo Credit: Julia Teichmann

In cannabis trials against pain, people who take placebos report feeling largely the same level of pain relief as those who consume the active cannabinoid substance. Still, these studies receive significant media coverage regardless of the clinical outcome, report researchers from Karolinska Institutet in Sweden in a study published in JAMA Network Open.

“We see that cannabis studies are often described in positive terms in the media regardless of their results,” says the study’s first author Filip Gedin, postdoc researcher at the Department of Clinical Neuroscience, Karolinska Institutet. “This is problematic and can influence expectations when it comes to the effects of cannabis therapy on pain. The greater the benefit a treatment is assumed to have, the more potential harms can be tolerated.”

The study is based on an analysis of published clinical studies in which cannabis has been compared with placebo for the treatment of clinical pain. The change in pain intensity before and after treatment were the study’s primary outcome measurement.

The analysis drew on 20 studies published up to September 2021 involving almost 1,500 individuals.

Discovery of antibody structure could lead to treatment for Crimean Congo Hemorrhagic Fever virus

Scott D. Pegan, a professor of biomedical sciences
Photo Source: University of California, Riverside

A research team led by the University of California, Riverside, has discovered important details about how therapeutically relevant human monoclonal antibodies can protect against Crimean Congo Hemorrhagic Fever virus, or CCHFV. Their work, which appears online in the journal Nature Communications, could lead to the development of targeted therapeutics for infected patients.

An emerging zoonotic disease with a propensity to spread, CCHF is considered a priority pathogen by the World Health Organization, or WHO. CCHF outbreaks have a mortality rate of up to 40%. Originally described in Crimea in 1944–1945, and decades later in the Congo, the virus has recently spread to Western Europe through ticks carried by migratory birds. The disease is already endemic in Africa, the Balkans, the Middle East, and some Asian countries. CCHFV is designated as a biosafety level 4 pathogen (the highest level of biocontainment) and is a Category A bioterrorism/biological warfare agent. There is no vaccine to help prevent infection and therapeutics are lacking.

Scott D. Pegan, a professor of biomedical sciences in the UCR School of Medicine, collaborated on this study with the United States Army Medical Research Institute of Infectious Diseases, or USAMRIID, which studies CCHFV because of the threat it poses to military personnel around the world. They examined monoclonal antibodies, or mAbs, which are proteins that bind to antigens — foreign substances that enter the body and cause the immune system to mount a protective response.

In a previous publication, USAMRIID scientists Joseph W. Golden and Aura R. Garrison reported that an antibody called 13G8 protected mice from lethal CCHFV when administered post-infection. They provided Pegan with the sequence information for that antibody, clearing the way for UCR to “humanize” it and conduct further research.

Squirrel sperm and feet tell a different climate change story

Cape ground squirrels are ecosystem engineers
Photo Credit: Gary Simons

Perhaps it’s time to replace the canary in a coal mine metaphor with a squirrel in the ground. Because two University of Manitoba studies found that climate change is altering ground squirrels’ sperm and feet, and this warns of big consequences potentially coming to endangered ecosystems.

These subtle squirrel changes concern UM researchers Jane Waterman and Miya Warrington, who tuned into them only recently and published their latest findings in the latest Journal of Mammalogy.

It began last year when they found that some male Richardson’s ground squirrels, a species found throughout the Canadian prairies, emerged from hibernation during a particularly warm winter with non-motile sperm. This non-lethal effect of climate change fortunately did not result in fewer young that year, although other negative consequences of males “shooting blanks” may emerge in other species or situations.

Intrigued by this finding, they then looked at what non-lethal affects climate change was having on African ground squirrels in the grasslands of South Africa.

Researchers take first step towards controlling photosynthesis using mirrors

The researchers used ultrafast laser spectroscopy
Photo Credit: Pavel Chabera

With the help of mirrors, placed only a few hundred nanometers apart, a research team has managed to use light more efficiently. The finding could eventually be useful for controlling solar energy conversion during photosynthesis, or other reactions driven by light. For example, one application could be converting carbon dioxide into fuel.

The sunlight that hits Earth for one hour is almost equivalent to the total energy consumption of mankind for an entire year. At the same time, our global emissions of carbon dioxide are increasing. Harnessing the sun's energy to capture greenhouse gas and then convert it into fuel is a hot research field.

A research team at Lund University in Sweden was previously able to show that with ultrafast laser spectroscopy, and the help of advanced materials, it would be possible to reduce the levels of greenhouse gases in the atmosphere in the long term. In their latest study in Nature Communications, the team has made new progress when it comes to taking advantage of light.

Why steamed hay can lead to protein deficiency in horses

Photo Credit: Manfred Richter

Hay treated with hot steam is safer for horses but provides them with less protein. The horse forage is treated with steam to rid it of potentially harmful microorganisms and to bind particles that could otherwise be inhaled. However, a team of scientists from Martin Luther University Halle-Wittenberg (MLU) has discovered that this also causes a chemical reaction which damages the proteins in the hay and makes them harder for horses to digest. This can lead to signs of nutrient deficiency in the animals and, for example, impair growth or muscle development. The team reports on their scientific work in the journal Animals.

Hot steam is used to heat hay up to 100 degrees Celsius, which kills harmful microorganisms and binds fungal spores and dust to the hay. "Many horses suffer from lung problems such as equine asthma. The steaming process virtually eliminates all of the living microorganisms and particles in the hay that could be inhaled during feeding and damage the lungs. In theory, the end result is a very good forage," explains Professor Annette Zeyner from the Institute of Agricultural and Nutritional Sciences at MLU.

Featured Article

Hypoxia is widespread and increasing in the ocean off the Pacific Northwest coast

In late August, OSU's Jack Barth and his colleagues deployed a glider that traversed Oregon’s near-shore waters from Astoria to Coos Bay...

Top Viewed Articles