Earth

How do we become a complex, integrated multicellular organism from a single cell?

While developmental biologists have long researched this fundamental question, Stanford University biologist and HHMI investigator Dominique Bergmann's recent work on the plant Arabidopsis thaliana has uncovered surprising answers.

In a new study, published April 5 in Developmental Cell, led by Bergmann and postdoctoral scholar Camila Lopez-Anido, researchers used single-cell RNA sequencing technologies to track genetic activity in nearly 20,000 cells as they formed the surface and inner parts of an Arabidopsis leaf. Through this highly detailed technique, the researchers captured transient and rare cell states and found a surprising abundance of ambiguity in how cells traversed various identities, particularly early on within the stem cell population.

"All the cells are coordinated, and yet they're all individuals with their own genetic programs," said Bergmann, who is the Shirley R. and Leonard W. Ely, Jr. Professor in the School of Humanities and Sciences and senior author of the study. "And so we're really working to appreciate that balance between seeing what's new and special and unique about each one while also recognizing how they are working together."

While many scientists in this field focus on fruit flies and roundworms, some aspects of biological development will only be understood by studying other organisms - such as the plant Arabidopsis thaliana, which is the Bergmann lab's specialty.

"As we think about flexibility and resilience in the face of a changing world, we want to learn more about how organisms can manage to build functional bodies when they are under stress or exposed to extreme environments," said Lopez-Anido, who is lead author of the study. "This requires research with organisms that have flexible and tunable lifestyles, such as the plants we study."

As part of a family of artists, Lopez-Anido also embraced a uniquely artistic perspective to interpret and share this research. Within the paper itself, she used a pointillism-inspired analysis software to elegantly organize and visualize her massive dataset. Additionally, her sister, artist Virginia Lopez-Anido, created artwork inspired by Camila's research, which will be featured on the cover of Developmental Cell.

Surprising details

While previous experiments on Arabidopsis had worked out some of the important genes and steps in making specialized cells, this new cell-by-cell data fills in additional details of development. The researchers found, for example, that cells might double-back on the developmental path they seemed to be following, and that it was also possible to jump ahead. They also noticed that there may be differences in the way new stem cells regulated transitions between cell types relative to old stem cells; and whereas they had previously known of core steps in cell differentiation, they saw there were actually many small, seemingly continuous steps along the way.

One especially intriguing finding concerns a crucial gene, called SPEECHLESS, that plays a role in the formation of pores, called stomata, through which the plant exchanges gases and regulates water content. The Bergmann lab has studied SPEECHLESS extensively, but the new data hinted that it was expressed for a longer stretch of the developmental process than they expected. In a follow-up experiment, the researchers were able to selectively remove the gene after it completed its known role but sooner than the new data said it was done being expressed. Sure enough, the developmental programs went off track - and the researchers are now working to figure out why.

"It was a contradiction of what we thought we knew and it was really exciting," Bergmann said. "It makes us want to dig in to other unexpected details - what might look like insignificant blips in the data - and see what we've missed."

Bergmann credits Lopez-Anido and this work with inspiring several avenues of research, including reconsidering what it means to be a stem cell, reframing events that define final differentiation stages and reevaluating what it means to be born as a cell on the top versus bottom of a leaf.

Art, science and mentorship

Analyzing cell identities from nearly 20,000 cells - and 30,000 genes - required machine learning algorithms. So, Lopez-Anido created an organizational framework built around one of the most widely used analysis tools, which is called Seurat after pointillist painter Georges Seurat. As in pointillism, individual dots, which represented individual cells and their specific gene expression signatures, blended together in visualizations that enabled the researchers to see large-scale trends.

Virginia Lopez-Anido visualized Camila's work in another way. She developed a drawing series on the nature of scientific inquiry (Untitled, pencil on paper, 8.5 x 11.7in, 2021), as well as a clay model series of tissue landscapes inspired by scanning electron microscope images of stomata (Untitled, digital photograph, 2021), which is the art that will grace the cover of Developmental Cell.

"I like to engage with artists and scholars across disciplines because it can bring new layers of meaning to science - and make science more accessible, which is very important to me," said Camila Lopez-Anido, who has taught scientific literacy at Bard College through their Citizen Science program and will soon begin work as an assistant professor of biology at Reed College. "I'm looking forward to fostering more of these meaningful research experiences and collaborations for my mentees."

New research shows the permanent rise of oxygen in our atmosphere, which set the stage for life as we know it, happened 100 million years later than previously thought.

A significant rise in oxygen occurred about 2.43 billion years ago, marking the start of the Great Oxidation Episode -- a pivotal moment in Earth's history. 

An international research team including a UC Riverside scientist analyzed rocks from South Africa formed during this event. Findings, published this week in the journal Nature, include the discovery that oxygen fluctuated dramatically after its early appearance until it became a permanent constituent of the atmosphere much later.

These fluctuations reinforce a direct link between atmospheric oxygen and concentrations of greenhouse gases such as methane, helping to explain some of the most extreme climate changes in the planet's past.

During the same period, ancient Earth experienced four glaciations -- periods when the whole planet was covered with ice and snow for millions of years. According to UC Riverside geologist Andrey Bekker, changes in atmospheric oxygen levels began and ended these events. 

Scientists have often wondered how the planet could have emerged from the periods in which ice and snow covered everything, including the oceans. According to Bekker, increases in atmospheric oxygen levels resulted in low concentrations of greenhouse gases, such as methane and carbon dioxide. This ushered in global glaciations by maintaining surface conditions below the water-freezing temperature. 

Volcanoes also continued to erupt on the frozen planet, building required high levels of carbon dioxide in the atmosphere to exit from climatic catastrophe by warming the planet and melting the snow and ice.

"Before this work, we all wondered why the fourth glacial event happened if oxygen was already a steady component in the atmosphere," Becker said. "We found it was not steady. The permanent rise of oxygen actually occurred after the fourth, final glaciation in the Paleoproterozoc Era, and not before it, and this solves what had previously been a major puzzle in our understanding." 

The Great Oxidation Episode ushered in a 1.5 billion-year period of subsequent environmental stability, which lasted until a second major transitional period, marked by rising atmospheric oxygen and similar climatic changes at the end of the Precambrian time. 

"We thought once oxygen increased it wouldn't ever return back to lower levels," Bekker said. "Now we have learned it fluctuated to very low levels and this could have dramatic implications in terms of understanding extinction events and the evolution of life."

Open questions include the reasons for these multiple fluctuations, and whether complex life could have evolved and then died out again in response to them, said Simon Poulton, a biogeochemist at Leeds University who led the research. 

"We cannot begin to understand the causes and consequences of atmospheric oxygenation, the most significant control on Earth's habitability, if we do not know when permanent atmospheric oxygenation actually occurred," he said. "Now at last we have that piece of the puzzle."

WASHINGTON, April 5, 2021 -- Forever chemicals are known for being water-, heat- and oil-resistant, which makes them useful in everything from rain jackets to firefighting foams. But the chemistry that makes them so useful also makes them stick around in the environment and in us -- and that could be a bad thing: https://youtu.be/tqKEG5LxPiY.

A lot of people think regret must be a good thing because it helps you not repeat a mistake, right?

But that turns out not to be the case. Not even when it comes to casual sex, according to new research from the Norwegian University of Science and Technology's (NTNU) Department of Psychology.

"For the most part, people continue with the same sexual behaviour and the same level of regret," says Professor Leif Edward Ottesen Kennair.

So, we repeat what we thought was a mistake, and we regret it just as much the next time around.

Professor Kennair and colleagues professor Mons Bendixen and postdoctoral fellow Trond Viggo Grøntvedt have investigated whether sexual regret is functional, that is, whether it contributes to any change in behaviour.

The participants in the study answered a questionnaire about sexual regret two times, at approximately 4.5 month intervals. This approach makes it possible to study changes over shorter periods of time.

Both women and men might regret what they did the last time an opportunity for casual sex arose. But they often regret completely different choices.

Women tend to regret having had casual sex more than men. Men, on the other hand, regret not taking advantage of a casual sex opportunity markedly more than women.

"We wanted to examine if their level of regret contributed to a change in behaviour the next time around," says Bendixen.

"A lot of emotions are functional, like disgust that protects against infection and fear that protects against danger. An evolutionary approach has helped us understand anxiety by understanding the function of fear: fight-flight-freeze is about avoiding danger and defending ourselves against it," says Kennair.

Many people assume that emotions have a function

Many psychologists assume that regret and other emotions have a function: that they'll influence our behaviour so that we modify it. For example, after experiencing negative emotions, we will change our behaviour to reduce the risk of having those negative feelings later.

"Researchers have found that most people believe this is true for regret. They assume that regret is actually a helpful negative feeling. People assume it guides them not to repeat what they regretted," says Grøntvedt.

If regret works that way, then wouldn't men more often have casual sex the next time the opportunity arose? And, you would think that women's regret would lead them to choose better partners, have less frequent casual sex or try harder to get into steady relationships.

But no, that's not what happens. The findings from the study show that we don't learn from what we perceived as a mistake.

So why is that? Why don't we learn from our mistakes?

Probably because our behaviour depends on our personality, which is something quite different and more complicated than a shorter or more prolonged feeling of regret.

We are mostly just who we are, and when the opportunity arises and horniness take over, or doesn't, we probably react just like the time before.

"We are not that surprised," Kennair says. "If regret helped, would not most sinners eventually become saints? What do you regret the most often? Has it changed your behaviour?" he asks.

Regret is flexible, not constant. Or, as psychologists say, regret is adaptive. It changes according to the conditions.

"We have repeated that regret is adaptive in all our articles on the subject in recent years. And now we have tested it," says Kennair.

No one else has tested regret for sexual behaviour. Perhaps researchers have assumed that they knew enough? Even outstanding people in the field have assumed that regret would help us learn.

"We found little information on this topic. But both most researchers and people in general believe that regret is wise," says Grøntvedt.

Do you really need to spend so much time being regretful?

"Maybe it would be smart instead to think about what we regret in everyday life, and what we actually do so often that we get ample opportunity to regret it," Kennair says.

Have you exercised enough lately? Did you eat too much? Done everything you should? Said something you shouldn't have said? Does it help to regret things sometimes? No? This is a bit like ruminating, which a lot of people with depression assume is a smart thing to do, even if they become more depressed from doing it.

"And yet, there are some folks who think that depressive ruminating and worry are a good idea. But the way we treat depression and generalized anxiety disorders is by helping people to stop ruminating and to stop worrying. Not everything people do, think or feel is an evolutionary adaptation - sometimes it is not appropriate either," Kennair says.

Piping plover breeding groups in the Northern Great Plains are notably connected through movements between habitats and show lower reproductive rates than previously thought, according to a new U.S. Geological Survey study. These new findings point to a need for further studies and suggest the species may show a higher extinction risk than currently presumed.

Piping plovers are small-bodied, short-distance migratory shorebirds. The Northern Great Plains population has been listed as a threatened species under the U.S. Endangered Species Act since 1985. Previously, wildlife managers had assumed four separate breeding groups within the Northern Great Plains and that individuals from these groups moved infrequently between habitats. Earlier studies based on this assumption resulted in a low extinction risk for the species.

Scientists analyzed movement, survival and renesting rates in two of the assumed breeding groups of piping plovers over four distinct management units along the Missouri River and alkaline wetlands distributed throughout the prairie pothole region from 2014 - 2019. Piping plover reproductive rates were studied between 2014 - 2016. The study areas are within North Dakota, South Dakota and Montana and include the U.S. alkali wetlands, Lake Sakakawea, the Garrison Reach of the Missouri River, and Lake Oahe.

Results show river and alkali wetland habitats appear to be of higher quality than reservoir habitats, which had lower annual survival, increased movement away from the habitat, lower renesting success, and lower reproductive output.

Habitat availability affected nearly every parameter examined in this study. In general, when more habitat was available, piping plover vital rates improved. These findings support the current focus of managing the Missouri River for abundant breeding habitat for piping plovers.

Study findings show managing for successful first nests for Northern Great Plains piping plovers is key to improving reproductive output. Piping plovers are intensively managed throughout their range, and in the Northern Great Plains, management of habitat, water and predation, including vegetation removal and protective fences around nests, are common conservation strategies. Therefore, intensive management focused on the protection of early nests or first nest attempts would likely be more effective than strategies that assume equivalent productivity from renests.

The study also shows that piping plovers move between the northern Missouri River habitat and the U.S. alkali wetlands at a rate that is substantially higher than previously assumed. Further, movement rates were unbalanced and varied between hatch-year and adult plovers. Adults were more likely to forego breeding altogether than to relocate to alternate management units and breed. This implies that either the rates of movement or the way local bird populations are managed may need to be reevaluated.

A new study shows a correlation between the end of solar cycles and a switch from El Nino to La Nina conditions in the Pacific Ocean, suggesting that solar variability can drive seasonal weather variability on Earth.

If the connection outlined in the journal Earth and Space Science holds up, it could significantly improve the predictability of the largest El Nino and La Nina events, which have a number of seasonal climate effects over land. For example, the southern United States tends to be warmer and drier during a La Nina, while the northern U.S. tends to be colder and wetter.

"Energy from the Sun is the major driver of our entire Earth system and makes life on Earth possible," said Scott McIntosh, a scientist at the National Center for Atmospheric Research (NCAR) and co-author of the paper. "Even so, the scientific community has been unclear on the role that solar variability plays in influencing weather and climate events here on Earth. This study shows there's reason to believe it absolutely does and why the connection may have been missed in the past."

The study was led by Robert Leamon at the University of Maryland-Baltimore County, and it is also co-authored by Daniel Marsh at NCAR. The research was funded by the National Science Foundation, which is NCAR's sponsor, and the NASA Living With a Star program.

Applying a new solar clock

The appearance (and disappearance) of spots on the Sun -- the outwardly visible signs of solar variability -- have been observed by humans for hundreds of years. The waxing and waning of the number of sunspots takes place over approximately 11-year cycles, but these cycles do not have distinct beginnings and endings. This fuzziness in the length of any particular cycle has made it challenging for scientists to match up the 11-year cycle with changes happening on Earth.

In the new study, the researchers rely on a more precise 22-year "clock" for solar activity derived from the Sun's magnetic polarity cycle, which they outlined as a more regular alternative to the 11-year solar cycle in several companion studies published recently in peer-reviewed journals.

The 22-year cycle begins when oppositely charged magnetic bands that wrap the Sun appear near the star's polar latitudes, according to their recent studies. Over the cycle, these bands migrate toward the equator -- causing sunspots to appear as they travel across the mid-latitudes. The cycle ends when the bands meet in the middle, mutually annihilating one another in what the research team calls a terminator event. These terminators provide precise guideposts for the end of one cycle and the beginning of the next.

The researchers imposed these terminator events over sea surface temperatures in the tropical Pacific stretching back to 1960. They found that the five terminator events that occurred between that time and 2010-11 all coincided with a flip from an El Nino (when sea surface temperatures are warmer than average) to a La Nina (when the sea surface temperatures are cooler than average). The end of the most recent solar cycle -- which is unfolding now -- is also coinciding with the beginning of a La Nina event.

"We are not the first scientists to study how solar variability may drive changes to the Earth system," Leamon said. "But we are the first to apply the 22-year solar clock. The result -- five consecutive terminators lining up with a switch in the El Nino oscillation -- is not likely to be a coincidence."

In fact, the researchers did a number of statistical analyses to determine the likelihood that the correlation was just a fluke. They found there was only a 1 in 5,000 chance or less (depending on the statistical test) that all five terminator events included in the study would randomly coincide with the flip in ocean temperatures. Now that a sixth terminator event -- and the corresponding start of a new solar cycle in 2020 -- has also coincided with an La Nina event, the chance of a random occurrence is even more remote, the authors said.

The paper does not delve into what physical connection between the Sun and Earth could be responsible for the correlation, but the authors note that there are several possibilities that warrant further study, including the influence of the Sun's magnetic field on the amount of cosmic rays that escape into the solar system and ultimately bombard Earth. However, a robust physical link between cosmic rays variations and climate has yet to be determined.

"If further research can establish that there is a physical connection and that changes on the Sun are truly causing variability in the oceans, then we may be able to improve our ability to predict El Nino and La Nina events," McIntosh said.

NEW YORK, APRIL 5, 2021 -- Nine of the hottest years in human history have occurred in the last decade. Without a major shift in this climate trajectory, the future of life on Earth is in question. Should humans, whose fossil-fueled society is driving climate change, use technology to put the brakes on global warming?

Every month since September 2019 the Climate Intervention Biology Working Group, a team of internationally recognized experts in climate science and ecology, has gathered remotely to bring science to bear on that question and the consequences of geoengineering a cooler Earth by reflecting a portion of the sun's radiation away from the planet -- a climate intervention strategy known as solar radiation modification (SRM).

The group's seminal paper, "Potential ecological impacts of climate intervention by reflecting sunlight to cool Earth," was published in the most recent Proceedings of the National Academy of Sciences of the United States (PNAS).

"Participating in this working group has been quite eye-opening for me," said co-author Peter Groffman, an ecosystem ecologist at the Advanced Science Research Center at The Graduate Center, CUNY and the Cary Institute of Ecosystem Studies. "I was unaware that modeling climate intervention was so advanced, and I think that climate modelers were unaware of the complexities of the ecological systems being affected. It is a strong reminder of the importance of the need for multi-disciplinary analysis of complex problems in environmental science."

The interdisciplinary team is co-led by Phoebe Zarnetske, community ecologist and associate professor in Michigan State University's Department of Integrative Biology and the Ecology, Evolution, and Behavior program, and ecologist Jessica Gurevitch, distinguished professor in the Department of Ecology and Evolution at Stony Brook University.

Conversations between Gurevitch and climate scientist Alan Robock, distinguished professor in the Department of Environmental Sciences at Rutgers University, gave rise to the pioneering group, which is more aware than most that geoengineering Earth's atmosphere is more than just a science-fiction scenario.

"There is a dearth of knowledge about the effects of climate intervention on ecology," said Zarnetske. "As scientists, we need to understand and predict the positive and negative effects it could have on the natural world, identify key knowledge gaps, and begin to predict what impacts it may have on terrestrial, marine, and freshwater species and ecosystems if it were adopted in the future."

The costs and technology needed to reflect the Sun's heat back into space are currently more attainable than other climate intervention ideas like absorbing carbon dioxide (CO2) from the air. The working group anticipates their lively discussions and open access paper will encourage an explosion of scientific investigation into how a climate intervention strategy known as solar radiation modification (SRM), in tandem with greenhouse gas emissions reduction, would affect the natural world.

The feasibility of planetary-wide SRM efforts hinge on accurate predictions of its myriad outcomes provided by the well-established computer simulations of the Geoengineering Model Intercomparison Project (GeoMIP). The PNAS paper lays the foundation for expanding GeoMIP's scope to include the incredible range and diversity of Earth's ecosystems.

"While climate models have become quite advanced in predicting climate outcomes of various geoengineering scenarios, we have very little understanding of what the possible risks of these scenarios might be for species and natural systems," Gurevitch explained. "Are the risks for extinction, species community change, and the need for organisms to migrate to survive under SRM greater than those of climate change, or does SRM reduce the risks caused by climate change?"

"Most of the GeoMIP models only simulate abiotic variables, but what about all of the living things that are affected by climate and rely on energy from the sun?" Zarnetske added. "We need to better understand the possible impacts of SRM on everything from soil microorganisms to monarch butterfly migrations to marine systems."

Zarnetske's Spatial and Community Ecology Lab (SpaCE Lab) specializes in predicting how ecological communities respond to climate change across scales from the microcosm to the global, making it uniquely poised to assist the working group in illuminating vital data for future SRM scenarios such as stratospheric aerosol intervention (SAI), the focus of the paper.

SAI would reduce some of the Sun's incoming radiation by reflecting sunlight back into space, similar to what happens after large volcanic eruptions. Theoretically, it would be possible to continuously replenish the cloud and control its thickness and location to achieve a desired target temperature.

But the paper reveals the under-researched complexity of cascading relationships between ecosystem function and climate under different SAI scenarios. In fact, they argue, climate change mitigation must continue regardless of whether SRM is adopted, and the question remains whether some or any SRM can be beneficial in addition to decarbonization efforts.

"Although SAI may cool Earth's surface to a global temperature target, the cooling may be unevenly distributed, affecting many ecosystem functions and biodiversity," Zarnetske said. "Rainfall and surface ultraviolet radiation would change, and SAI would increase acid rain and would not mitigate ocean acidification."

In other words, SRM is not a magic bullet for solving climate change. Until the working group's efforts inspire new research into the effects of different climate intervention scenarios, SRM is more akin to a shot in the dark.

"We hope that this paper will spark a lot more attention to this issue and greater cooperation between scientists in the fields of climate science and ecology," added Gurevitch.

On-surface synthesis has received great attention as a method to create atomically-precise one-dimensional (1D) and two-dimensional (2D) polymers with intriguing properties. In particular, graphene nanoribbons (GNRs), a category of quasi-1D nanomaterials derived from graphene, have been widely studied due to their tunable electronic properties and potential applications in semiconductor devices, such as field-effect transistors and spintronics. A series of top-down approaches have been pursued to produce GNRs, but a lack of control over the ribbon width and edge structure has hindered their further development.

In 2010, Cai et al. firstly reported the fabrication of an atomically-precise armchair GNR (AGNR) on the Au(111) surface using a bottom-up approach. The basic mechanism involves thermally-activated dehalogenation, surface-assisted polymerization and finally cyclodehydrogenation.

In the following decade, this bottom-up approach has been extended to synthesize a wide variety of GNRs, including AGNRs with different widths, zigzag GNRs, GNR heterojunctions, chiral GNRs and chemically- doped GNRs. Based on the periodic similarity of their electronic structures, AGNRs can be classified into three families, 3p, 3p+1 and 3p+2 (representing the number of carbon atoms in the narrow direction).

So far, few studies have focused on GNR synthesis on Cu(111) due to the stronger surface interaction, despite the lower temperature for dehalogenation. It has been shown that chiral GNRs can be synthesized on Cu(111) using the same precursor which yields non-chiral 7-AGNR on Au(111) and that dehalogenation can be reversible on Au(111) but not Cu(111), which implies that the reaction pathway and products achieved could be controlled through the choice of substrate.

A second approach to tailor the reaction pathway in surface-confined synthesis is to introduce different atomic species, which has been considered in only a few recent studies. Exposure to iodine creates a monolayer intercalated between the polymers and the Ag(111) surface that decouples their electronic interactions. In addition, hydrogen was shown to remove halogen by-products and to induce covalent coupling, and sulphur to switch the surface-confined Ullmann reaction on or off.

Prof. Lifeng Chi's research group in Soochow University recently investigated the effect of oxygen on the synthesis of 3-AGNRs by surface-confined Ullmann coupling and determined that it, instead, caused a 1D to 2D transformation of the organometallic (OM) structures.

Here, their objective was to investigate the synthesis of 3p-AGNRs on Cu(111), extending from the previous study on Au(111), and to examine the effect of oxygen on lateral fusion of 3-AGNRs, inspired by their potential to promote C-H activation.

Their investigation demonstrated the successful synthesis of 3p-AGNRs on Cu(111) via lateral fusion of poly(para-phenylene) (i.e. 3-AGNR). Introduction of co-adsorbed atomic oxygen substantially reduced the temperature required to induce the lateral fusion reaction. The identification of this catalytic effect could benefit on-surface synthesis that applies dehydrogenation reactions, not restricting to GNRs, and highlights the potential of additional atomic adsorbates to steer surface reactions.

A new technique that mimics the ancient Japanese art of kirigami may offer an easier way to fabricate complex 3D nanostructures for use in electronics, manufacturing and health care.

Kirigami enhances the Japanese artform of origami, which involves folding paper to create 3D structural designs, by strategically incorporating cuts to the paper prior to folding. The method enables artists to create sophisticated three-dimensional structures more easily.

"We used kirigami at the nanoscale to create complex 3D nanostructures," said Daniel Lopez, Penn State Liang Professor of Electrical Engineering and Computer Science, and leader of the team that published this research in Advanced Materials. "These 3D structures are difficult to fabricate because current nanofabrication processes are based on the technology used to fabricate microelectronics which only use planar, or flat, films. Without kirigami techniques, complex three-dimensional structures would be much more complicated to fabricate or simply impossible to make."

Lopez said that if force is applied to a uniform structural film, nothing really happens other than stretching it a bit, like what happens when a piece of paper is stretched. But when cuts are introduced to the film, and forces are applied in a certain direction, a structure pops up, similar to when a kirigami artist applies force to a cut paper. The geometry of the planar pattern of cuts determines the shape of the 3D architecture.

"We demonstrated that it is possible to use conventional planar fabrication methods to create different 3D nanostructures from the same 2D cut geometry," Lopez said. "By introducing minimum changes to the dimensions of the cuts in the film, we can drastically change the three-dimensional shape of the pop-up architectures. We demonstrated nanoscale devices that can tilt or change their curvature just by changing the width of the cuts a few nanometers."

This new field of kirigami-style nanoengineering enables the development of machines and structures that can change from one shape to another, or morph, in response to changes in the environment. One example is an electronic component that changes shape in elevated temperatures to enable more air flow within a device to keep it from overheating.

"This kirigami technique will allow the development of adaptive flexible electronics that can be incorporated onto surfaces with complicated topography, such as a sensor resting on the human brain," Lopez said. "We could use these concepts to design sensors and actuators that can change shape and configuration to perform a task more efficiently. Imagine the potential of structures that can change shape with minuscule changes in temperature, illumination or chemical conditions."

Lopez will focus his future research on applying these kirigami techniques to materials that are one atom thick, and thin actuators made of piezoelectrics. These 2D materials open new possibilities for applications of kirigami-induced structures. Lopez said his goal is to work with other researchers at Penn State's Materials Research Institute (MRI) to develop a new generation of miniature machines that are atomically flat and are more responsive to changes in the environment.

"MRI is a world leader in the synthesis and characterization of 2D materials, which are the ultimate thin-films that can be used for kirigami engineering," Lopez said. "Moreover, by incorporating ultra-thin piezo and ferroelectric materials onto kirigami structures, we will develop agile and shape-morphing structures. These shape-morphing micro-machines would be very useful for applications in harsh environments and for drug delivery and health monitoring. I am working at making Penn State and MRI the place where we develop these super-small machines for a specific variety of applications."

The kangaskhan, Australia's only species of endemic Pokemon in Pokemon Go, is commonly poached within its natural habitat by Pokemon trainers for use in fighting contests

Researchers used several species distribution modeling algorithms to predict how climate change, on top of the already existing human-induced pressures, would impact the distribution of the kangaskhan in the future

In addition to this, they found a way to measure how biased commonly used species distribution models are, and found that some models are so biased that their results weren't influenced by the data at all

The researchers compared these results to previously published models for hundreds of species of Australian mammals and found similar biases

This research has highlighted specific problems with common species distribution models, and has given scientists new statistical tools to refine them in the future

Kangaskhan (Garura kangaskhani) are two-meter-tall Pokemon, endemic to Australia. Although commonly spotted around cities and other urban areas, information is lacking about their basic biology and wider range distribution. Much of what is known is based on anecdotes from the public, especially unlicensed breeders, many of whom are not trained in scientific research. Today, kangaskhan are believed to be threatened due to frequent poaching of adults and eggs. The poaching is primarily motivated by the demand for these animals to be used in fighting contests. This pressure, combined with the fact that climate change is predicted to have a large impact in Australia over the next few decades, has resulted in a bleak outlook for this majestic Pokemon species.

Now, researchers in the Biodiversity and Biocomplexity Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) have taken an extensive look at how climate change will impact the existence of suitable habitat for kangaskhan. This study was published today in Methods in Ecology and Evolution.

"Apart from seeming to prefer partly cloudy weather, very little is known about the species' climatic preferences," said lead author Dr. Dan Warren, who previously worked as a researcher in Australia. "This makes it difficult to estimate the response of kangaskhan to environmental change, or how climate change might combine with the effects of poaching to impact the species' long-term survival. For this research, we used several well-known modeling methods to gain insight into how threatened kangaskhan really are."

With data that was initially recorded by hobbyists and professional trainers seeking out kangaskhan for exploitation, the researchers attempted to shed light on what the future holds for this species. Species distribution models were the obvious way to go. These models are a common way for scientists to predict changes in the availability of suitable habitat for a species, in response to estimated shifts in environmental parameters like rainfall, humidity, temperature, and vegetation cover.

In terms of the results, the models differed on what they predicted the future to be for the kangaskhan depending on the algorithms used. Three of the models predicted a decrease in habitat suitability, though differed substantially on the magnitude of this decline. Two other models switched their answer depending on the climate estimates used, and a sixth model predicted an increase in suitability of habitat. Policymakers and stakeholders should take this uncertainty into account and err on the side of caution when it comes to safeguarding the future of kangaskhan.

Aside from revealing uncertainty surrounding the long-term survival of kangaskhan, the research has also shed light on how scientists can calculate the biases that come with species distribution models. Every one of these models comes with a level of bias and uncertainty, depending on the choices made in the modeling process. For example, when predicting the implications of climate change, the amount of future CO2 emissions needs to be considered, and yet estimating this can be tricky as it's based on human behavior. Differences in these estimates can interact with other aspects of the modeling process, resulting in biases in predictions of how climate change will affect threatened and endangered species. Scientists know about these biases but have never found a way to measure them before, until now.

"We found that we could determine the level of bias with a simple statistical test," said Dr. Warren. "And, in doing so, we realized that some of these models could be so biased that the data didn't have much effect on their results... effectively the conclusion was picked based on study design regardless of what the data actually showed," said Dr. Warren.

In addition to the kangaskhan, the researchers demonstrated similar biases for these models by reexamining a previous study that built models for 220 species of Australian mammals, as well as a study that simulated artificial organisms in order to understand how well models estimated species' environmental tolerances. The researchers hope that by revealing these biases they are providing a more secure future for kangaskhan and the rest of the world's biodiversity.

Dr. Warren emphasized that although the study itself might seem strange, what it's revealed will actually go on to help other researchers create more robust estimates of species distribution. His primary reason for choosing to do this research on a Pokemon character was to engage a broader audience with issues that conservation scientists regularly need to think about.

"It's a bit silly but it's also cool science," said Dr. Warren. "Stakeholders use these models for predicting a number of important ecological phenomena, from the effects of climate change, to the dispersal of diseases and invasive species, so having a firm understanding of the biases the models might have is important. We've just scratched the surface of what we can do with this method so I think this could be a useful tool for a whole bunch of things."

His final point was a word of caution with respect to the culture that surrounds Pokemon. "It's specifically based around over-exploitation with the tagline 'gotta catch them all.' The rarer they get, the more valuable they get. This is like some of the larger tuna species, which are in serious danger of going extinct. We might have focused on climate change in this study but, for many Pokemon (and many species around the world), overexploitation should also be a concern."

Oak Brook, IL - The April edition of SLAS Discovery is a special issue on advances in protein degradation curated by guest editors M. Paola Castaldi, Ph.D., and Stewart L. Fisher, Ph.D.

Targeted protein degradation has generated interest within the drug discovery arena due to the inhibition of one particular function of a protein not often delivering the successful results that comes from whole-protein depletion. The pharmacology of PROTACs present challenges, however, namely for the development of orally bioavailable drugs. In the article "Target Validation Using PROTACs: Applying the Four Pillars Framework" authors Rados?aw P. Nowak, Ph.D., and Lyn H. Jones, Ph.D., describe the application of a translational pharmacology framework (the four pillars) to expedite PROTAC development by informing pharmacokinetic-pharmacodynamic (PKPD) understanding and helping clarify structure-activity relationships. Nowak and Jones hope that the four pillars will serve as a useful guideline to those developing targeted protein degraders and help establish PROTAC molecules as target validation chemical probes.

The April issue of SLAS Discovery includes three articles of original research.

These include:

Exploring the Biology of Degraders -- Simultaneous Detection of Protein Target Engagement and Functional Readout for In-Depth Characterization of Targeted Protein Degraders

A Method for Determining the Kinetics of Small Molecule Induced Ubiquitination

CDK Family PROTAC Degradation Profiling Reveals Differential Family Member Responses and Cell-Cycle Dependent Degradation of CDK

Other articles include:

Target Validation Using PROTACs: Applying the Four Pillars Framework

E3 Ligase Ligands for PROTACs: How They Were Found and How to Discover New Ones

Delivering Best Practice PROTACs Projects -- Lessons from AZ Experience.

High-Throughput Assay Technologies for Accelerating the Discovery and Optimization of Targeted Protein Degradation Therapeutics

The Vital Role of Proteomics in Characterizing Novel Protein Degraders

Non PROTAC Small Molecule Degraders -- An Exciting Novel Modality?

Development of a Novel SNAP-Epitope Tag/Near Infrared Imaging Assay to Quantify G Protein-Coupled Receptor Degradation in Human Cells

The current method of manufacturing carbon nanotubes--in essence rolled up sheets of graphene--is unable to allow complete control over their diameter, length and type. This problem has recently been solved for two of the three different types of nanotubes, but the third type, known as 'zigzag' nanotubes, had remained out of reach. Researchers with Japan's National Institutes of Natural Sciences (NINS) have now figured out how to synthesize the zigzag variety.

Their method is described in the journal Nature Chemistry, published on January 25.

Thanks to carbon's unique capacity to combine with other atoms to form molecules, when it combines with itself, it can do so in many structurally different ways (such as diamonds and graphite) with different properties. In recent decades, shapes such as graphene--a layer of carbon one atom thick formed from a hexagonal honeycomb-like lattice--have been produced. Another of these different forms, or 'allotropes,' that can be produced is a hollow cylinder of graphene known as a nanotube.

When the hexagons of carbon in the nanotube come together in this honeycomb lattice, they form either an armchair, zigzag or chiral configuration. The name 'zigzag' is used for the configuration in which the 'path' of each molecular bond between carbon atoms is directed first leftward by 60 degrees, then rightward by 60 degrees, then left 60 degrees, then right 60 degrees again: a zigzag pattern. The name 'armchair' describes a path that moves twice left, then twice right, before repeating. This pathway supposedly looks a bit like an armchair, hence the name. A third type, chiral, sits between these two forms, along with its mirror image.

If one were able to take a knife and slice through these tubes twice horizontally against the lengthwise axis, one could produce a 'belt' of nanotube, composed of 12 carbon hexagonal rings. Such a belt is called a 'nanobelt'.

Efforts at production of these nanobelts have been the subject of much scholarly investigation. This is because of the limitations of conventional manufacture of nanotubes, which takes what is termed a 'top-down' form. Top-down manufacture involves the pulverizations of a bulk mass of carbon into a powder, after which the nanotubes randomly form themselves into one or more of the three configuration types.

"The problem here is that you can't control which configuration type is formed, or the diameter, or even the length," said Yasutomo Segawa, of the Institute for Molecular Science at NINS and corresponding author for the paper. "But if you can build a nanotube from the bottom up, from the 'seed' of a nanobelt, then you control all these three aspects."

Previous research in 2019 had been able to produce armchair and chiral nanobelts, but not the third type - the zigzag.

And now for the first time, the researchers were able to form a zigzag nanobelt. The key to the nanobelt synthesis strategy was the bridging of the hexagonal rings by an oxygen atom (the addition of an oxanorbornadiene unit). They were then able to use X-ray crystallography to confirm that this structure, which had been predicted by theoretical calculations, was indeed forming in the real world.

With this third nanobelt synthesis, all three types of nanotubes--armchair, chiral, and zigzag--are in principle now available. This is a great step towards the bottom-up synthesis of carbon nanotubes made to order.

The next step is to take this proof of concept through to actual structure-selective bottom-up synthesis of carbon nanotubes, by using the synthesis of carbon nanotubes using their nanobelts as seeds.

A study led by Queen Mary University of London researchers has compared the performance and acceptability of a urine test and four different vaginal self-sampling collection devices to detect high risk Human Papilloma Virus (HPV).

Corresponding author Professor Jack Cuzick from Queen Mary University of London said: "Uptake of cervical screening has been declining in the UK in recent years, and self-sampling is an attractive alternative to clinician collected samples, initially in non-attenders but potentially for all women as the primary option.

"Cost and simplicity of use are important factors, and in low- and middle-income countries self-sampling may prove to be the only practical cost-effective option. High performance and acceptability of self-sampling is essential if this is to become the first option. Understanding preferences for a urine rather than a vaginal sample is important, and perhaps a choice should be offered."

The trial recruited women referred to the Royal London Hospital colposcopy clinic because of a positive cervical screening result. Those who joined the study were asked to provide a urine sample and to take two vaginal self-samples, using either a dry flocked swab and dacron swab, or a HerSwab and Qvintip device.

Of 600 vaginal sample pairs suitable for analysis, 505 were accompanied by a urine sample. All samples were tested at Queen Mary's Wolfson Institute of Preventive Medicine, with HPV determined using the Becton Dickinson Onclarity test.

All methods except HerSwab gave similar HPV positivity rates, but the highest sensitivity for abnormal cancer precursor lesions was seen with either the dry flocked swab or the dacron swab. Cellularity of the collected sample was highly variable for Herswab, but not for the other devices.

Survey results evaluating the women's experiences with sampling showed that there were no clear user preferences between devices, but that they found urine easy to collect and were more confident they had taken the sample correctly.

Many slopes in the Campania region are covered with layers of volcanic soil, the result of repeated eruptions over the course of millennia. As the impacts of climate change worsen, including the occurrence of very intense and short rainfall in localized areas, there is a growing need, especially in this and other Italian regions that are vulnerable to landslides, to understand the dynamics that induce such events more precisely and develop models that can predict them. When employed through adequate early warning systems, these tools can support decision-makers in adopting effective and efficient measures to protect people and the areas themselves from landslides.

To this end, the study Exploring ERA5 reanalysis potentialities for supporting landslide investigations: a test case from Campania Region (Southern Italy) by the CMCC Foundation identifies the potential of the fifth generation of atmospheric models (known as reanalysis dataset ERA5) developed by the European Centre for Medium-Range Weather Forecasts for improving the performance of early warning systems used, for example, by the Civil Protection (Protezione Civile).

On a slope covered by pyroclastic soil landslides are usually caused by a combination of two factors: the antecedent slope wetness conditions and the triggering condition represented by an intense precipitation event. The early warning system currently used by the Campania region uses the latter as the only indicator, ignoring the antecedent conditions of the soil. As a result, every time a precipitation event of a certain intensity is forecasted, whatever the state of the ground at that specific moment, the system returns a state of alert, pre-alarm or alarm. This increases the likelihood of false alarms and therefore of decisions - such as road closures - which may cause interruptions to services that in some cases could be avoided.

"Reanalyses are atmospheric models, the same ones that are used for forecasting. But they are usually used in back-analysis to reconstruct past weather conditions," explains Guido Rianna, CMCC researcher and co-author of the study. "Because of this characteristic, the purpose of reanalyses is not to forecast, but to homogenize, from a spatial and temporal point of view, data from different in situ monitoring systems - such as weather stations - or from remote sensing, such as satellites."

The fifth generation of reanalysis (ERA5) has a much better spatial resolution than the previous ones, providing atmospheric variables on grid cells of about 30 km side. In addition, it is possible to access free daily updated data through the Climate Data Store of the Copernicus Climate Change Service. This data ranges from 1979 up to 5 days before the consultation. Such a short time of data release allowed the authors of the study to assume - and then verify - a good performance of the tool not only for back-analysis studies but also for operational purposes such as the development of early warning systems.

"We first verified the reliability of the ERA5 reanalysis in reproducing rainfall histories leading to landslide events that actually occurred in the studied area," says Alfredo Reder, CMCC researcher and first author of the publication. "Next, we analysed the specific landslide event that occurred in Nocera Inferiore (Campania) on 4 March 2005. We verified that, at that event, the soil moisture estimations offered by ERA5, although not free of constraints and limitations, would have been able to observe a very high value in terms of water content along the entire cover. Thus, we have been able to take the final step of evaluating the possibility of using these reanalyses operationally for an early warning system. In the last phase of our research, we verified that the ERA5 datasets, if used as a proxy to support a decision, could improve the reliability of the forecasting model currently used in Campania, because they can provide information on antecedent slope wetness conditions, which are a predisposing factor for a landslide event."

The results of the study suggest the potential of this tool especially for minimizing false alarms, while avoiding missed alarms.

"Any expert on landslides in pyroclastic soils would say that the occurrence of an intense precipitation event in September in Campania, happening on a soil in dry condition, can rarely trigger a landslide," concludes Rianna. "But to date there is a lack of quantitative observational support to affirm this. Today, a Civil Protection decision-maker, on the basis of existing studies in the literature, could not fail to sound the alarm in the event of a forecast of a precipitation event with certain characteristics: he could not support this choice with data on the state of the soil in the prior period (except for a few limited slopes). Our research shows that ERA5 could fill this gap and therefore minimize the number of false alarms."

The results of this research apply to the case of pyroclastic landslides, which are characteristic of the studied area. The next step will be to verify the suitability of ERA5 reanalyses for the same purpose but in the case of other soil types, such as clay soils leading to slow landslides, which are characteristic of various areas of Italy, such as the southern Apennines and some areas of Basilicata and Campania.

In the 1960s, a national focus on hunger was essential to address major problems of undernutrition after World War II. In the 1990s, the nation shifted away from hunger toward "food insecurity" to better capture and address the challenges of food access and affordability.

Now, a new Viewpoint article argues that today's health and equity challenges call for the U.S. to shift from "food insecurity" to "nutrition insecurity" in order to catalyze appropriate focus and policies on access not just to food but to healthy, nourishing food.

The Viewpoint, by Dariush Mozaffarian of the Friedman School of Nutrition Science & Policy at Tufts University, Sheila Fleischhacker of Georgetown Law School, and José Andrés of World Central Kitchen, was published online in JAMA this week.

The concept of food security focuses on access to and affordability of food that is safe, nutritious, and consistent with personal preferences. In reality, however, the "nutritious" part often has been overlooked or lost in national policies and solutions, with resulting emphasis on quantity, rather than quality, of food, say the authors.

"Food is essential both for life and human dignity. Every day, I see hunger, but the hunger I see is not only for calories but for nourishing meals. With a new focus on nutrition security, we embrace a solution that nourishes people, instead of filling them with food but leaving them hungry," said Chef José Andrés, founder of World Central Kitchen.

The authors define nutrition security as having consistent access to and availability and affordability of foods and beverages that promote well-being, while preventing -- and, if needed, treating -- disease. Nutrition security provides a more inclusive view that recognizes that foods must nourish all people.

"'Nutrition security' incorporates all the aims of food security but with additional emphasis on the need for wholesome, healthful foods and drinks for all. COVID-19 has made clear that Americans who are most likely to be hungry are also at highest risk of diet-related diseases including obesity, diabetes, heart disease, and many cancers - a harsh legacy of inequities and structural racism in our nation. A new focus on nutrition security for all Americans will help crystallize and catalyze real solutions that provide not only food but also well-being for everyone," said first author Dariush Mozaffarian, dean of the Friedman School of Nutrition Science & Policy at Tufts University.

"It's the right time for this evolution," said Sheila Fleischhacker, adjunct professor at Georgetown Law School, who has drafted food, nutrition and health legislation and campaign positions at the local, state, tribal and federal levels. "By prioritizing nutrition security, we bring together historically siloed areas - hunger and nutrition - which must be tackled together to effectively address our modern challenges of diet-related diseases and disparities in clinical care, government food and food assistance policies, public health investments, and national research."

"The current approach is not sufficient," the authors write, and "traditionally marginalized minority groups as well as people living in rural and lower-income counties are most likely to experience disparities in nutrition quality, food insecurity, and corresponding diet-related diseases."