Tech

Imagine if we could use naturally-grown products, like plants and fruit, to store electricity that charges commonly used electronics like mobile phones, tablets, laptops or even electric cars?

Researchers from the University of Sydney have done just that, and have developed a method that uses durian and jackfruit waste to create energy stores for rapid electricity charging.

School of Chemical and Biomolecular Engineering academic Associate Professor Vincent Gomes explains how he and the research team managed to turn the tropical fruits into super-capacitors.

How does it work?

"Using durian and jackfruit purchased from a market, we converted the fruits' waste portions (biomass) into super-capacitors that can be used to store electricity efficiently," said Associate Professor Vincent Gomes.

"Using a non-toxic and non-hazardous green engineering method that used heating in water and freeze drying of the fruit's biomass, the durian and jackfruit were transformed into stable carbon aerogels -- an extremely light and porous synthetic material used for a range of applications.

"Carbon aerogels make great super-capacitors because they are highly porous. We then used the fruit-derived aerogels to make electrodes which we tested for their energy storage properties, which we found to be exceptional."

What are super-capacitors?

"Super-capacitors are like energy reservoirs that dole out energy smoothly. They can quickly store large amounts of energy within a small battery-sized device and then supply energy to charge electronic devices, such as mobile phones, tablets and laptops, within a few seconds," said Associate Professor Gomes.

"Compared to batteries, super-capacitors are not only able to charge devices very quickly but also in orders of magnitude greater charging cycles than conventional devices.

"Current super-capacitors are made from activated carbon which are nowhere near as efficient as the ones prepared during this project."

Why durian and jack fruit?

"Durian waste was selected based on the excellent template nature provides for making porous aerogels," said Associate Professor Gomes.

"The durian and jack-fruit super-capacitors perform much better than the materials currently in use and are comparable, if not better, than the expensive and exotic graphene-based materials.

"Durian waste, as a zero-cost substance that the community wants to get rid of urgently due to its repulsive, nauseous smell, is a sustainable source that can transform the waste into a product to substantially reduce the cost of energy storage through our chemical-free, green synthesis protocol."

What could this technology be used for?

"We have reached a point where we must urgently discover and produce ways to create and store energy using sustainably-sourced materials that do not contribute to global warming," said Associate Professor Gomes.

"Confronted with this and the world's rapidly depleting supplies of fossil fuels, naturally-derived super-capacitors are leading the way for developing high efficiency energy storage devices," he said.

High-definition images of minute objects are standard these days including the imaging of bacteria and viruses, and even molecules and individual atoms in extremely fine details. Atomic force microscopy, which involves bringing a vibrating tip into contact with or close to the sample surface, is often used for this purpose. Until now, however, the choice was between fast imaging techniques, which run the risk of destroying sensitive samples, and gentle imaging techniques that take more time.

Now, researchers from the Faculty of Electrical Engineering and Information Technology at TU Wien have succeeded in finding a way around this dilemma: instead of the previous standard method, which just involves directly vibrating a tiny arm with a fine tip, this method involves vibrating a plate with a smaller customised arm with an ultra-fine tip attached to it. By skilfully connecting the two components, the possible measuring speed can be increased to such an extent that even videos of sensitive objects should be possible, such as living cells that are in the process of reacting to a medication. TU Wien has already applied for a patent for the microstructure consisting of a plate and an arm that is intended to form the core of advanced future atomic force microscopes.

Feeling an image point by point

"In an atomic force microscope, we use a tiny arm, known as a cantilever, which is just a few micrometres in size. When the cantilever is vibrated at its resonant frequency, it vibrates extremely quickly, typically a few hundred thousand times per second," says Prof. Ulrich Schmid from the Institute of Sensor and Actuator Systems. The cantilever has an ultra-fine tip attached to it. When it comes very close to the surface of the sample, a force acts between the sample and the vibrating tip at the atomic level. This changes the vibrational movement of the cantilever; it vibrates in a slightly different way and this change is measured.

This measurement must be carried out point by point; a new measurement result is obtained for each part of the sample and all of these numerical values must then be combined into an image on the computer. In practice, the crucial factor is how long it takes to create such an image. If you want to image the object in a short amount of time, you need to use a cantilever that vibrates at high speed. "You can achieve this by making the cantilever more and more mechanically stiff," explains Ulrich Schmid. "However, the problem with this is that the stiffer and less flexible the vibrating part of the measuring apparatus is, the more likely it is to destroy the sample. For this reason, many biological samples could only previously be imaged using particularly gentle techniques, which take more time accordingly." It was therefore not previously possible to observe samples like this over a short time scale and visualise rapid changes.

Vibrating plate, gentle measurement

Researchers have now found a way to circumvent this problem using a physical trick, namely by attaching the cantilever to a small plate. Here, the plate vibrates in its resonant frequency instead of the cantilever. Certain resonant frequencies of the plate can be stimulated in a very specific way, causing the cantilever to passively move with it in the process. This means that the cantilever itself can be much softer than before, even at higher vibrational frequencies.

"We have produced a connected vibrating system consisting of cantilever and vibrating plate, which is far less stiff than a cantilever on its own even at high frequencies when vibrating at its own frequency," explains Jonas Hafner, "and less stiff means less destructive for sensitive samples."

The new measuring sensor works in liquids, which is particularly important for biological probes. A patent is already pending for the microstructure - this was applied for with the assistance of Research and Transfer Support at TU Wien, and the first important results have also been presented in two scientific publications.

The new sensing element can display its strengths anywhere where high measuring speeds are to be achieved for soft materials or surfaces. In future, it is intended to be used for biological samples or biochemical processes, but it could also play an important role in material research, such as for fragile polymer structures for example.

Suggesting that current non-smoking regulations may not be enough to minimize nonsmokers' exposure to thirdhand cigarette smoke, researchers report that concentrations of nicotine and smoking-related volatile organic compounds spiked when moviegoers entered a well-ventilated, non-smoking movie theater, exposing them to the equivalent of between one and 10 cigarettes of secondhand cigarette smoke. This is the first study to demonstrate real-time thirdhand smoke emissions in an indoor nonsmoking environment, the authors say, and while their case study takes place in a movie theater, the results are broadly applicable to a range of indoor environments worldwide. Roger Sheu et al. conclude that chemicals associated with cigarettes entered the theater by way of smokers' clothing and bodies, with especially high concentrations of smoking-related volatile organic compounds like toxic benzene and formaldehyde detected during late-night and R-rated films, when attendance is lower but the proportion of adults is higher. Previous research provides conclusive evidence for the harmful health effects of smoking--no level of exposure is considered safe. But while regulations have decreased smoking in public locations, pollutants from tobacco smoke remains a health hazard, especially for infants and children. Thirdhand exposure by inhaling evaporated gases or dusts that settle on surfaces after smoking, or from touching or ingesting the cigarette-related dust on surfaces, has been identified as part of this health threat. To observe how these chemicals are transferred from people to a nonsmoking environment, Sheu and colleagues used mass spectrometry to measure tracers of smoke in an empty non-smoking movie theater, before guests arrived, and as attendees took their seats. They also considered the impact of vaping. "Electronic cigarettes are not sources of most of the compounds we report here, and we did not observe enhancements in chemicals specifically concentrated in vaping emissions," says Drew Gentner, a researcher on the study. "However, we identify thirdhand vaping as a key area for future research. For example, we did see a lot of nicotine, which is present in vaping products. So nicotine from e-cigarettes could have also been transported by people and off-gassed in the theater."

ALEXANDRIA, Va. (March 4, 2020) -- Data science researchers at the University of Illinois have some March Madness advice based on new research: Pick top-seeded teams as the Final Four in your March Madness bracket and work backward and forward from there. If you are going to submit multiple brackets--as you can in the ESPN, CBS Sports and Yahoo Challenges--starting with the Final Four is still a good strategy, but make sure you also diversify your brackets as much as possible.

A paper describing the research behind this advice is published in the American Statistical Association's (ASA) Journal of Quantitative Analysis in Sports (JQAS) by Sheldon H. Jacobson (computer science faculty), Ian Ludden (computer science graduate student), Arash Khatibi (former graduate student) and Douglas M. King (industrial and enterprise systems engineering faculty).

"If you can only pick one bracket, then leaning heavily on the top seeds makes sense," said Jacobson. "However, all bracket challenges allow you to submit multiple entries. A person does not need all of their brackets to score well; just one will do." Jacobson's research on basketball brackets over the past decade has focused entirely on seeds, not teams, making his body of seed-centered work distinct.

Given there are 2^63 possible brackets, which is more than 9 quintillion (9 x 10^18) combinations, picking a bracket with all 63 games correct is highly unlikely, even if you can submit multiple brackets. So, Jacobson suggests focusing on your Final Four teams first, and then building backward and forward from those games. "Once you pick a set of Final Four teams, 12 additional game outcomes become fixed, effectively reducing the number of games that you must pick," Jacobson said. "Our research suggests that anything that can be done to reduce the uncertainty in your picks, while simultaneously expanding the diversity of your pool, will give you a step up in having a good scoring bracket amongst your set of brackets." More information can be found on Jacobson's Bracket Odds website at http://bracketodds.cs.illinois.edu/pool.html.

"For the 2016 through 2019 tournaments, our models produce many brackets that would have placed in the top 100 of the ESPN bracket challenge." Ludden said. "Our models that start by picking the Elite Eight or Final Four teams perform especially well, perhaps because they balance the two main risks: incorrect picks in the first two rounds, which may propagate through the tournament, and incorrect teams in the later rounds, where each game is worth more points."

Jacobson's seed-centered research has been integrated into the Bracket Odds website. Launched in 2012, the website--labeled as a University of Illinois STEM Learning Laboratory--draws together graduate and undergraduate students to apply data science methods to the tournament. The site has attracted more than 650,000 hits since its inception, providing insights and information for those interested in the mathematics of March Madness.

The website offers a smorgasbord of data analytics for people following the tournament. For example, one of the website calculators gives the probability of all number-one seeds reaching the Final Four to be 0.0155, or around once every 64 tournaments. Meanwhile, the probability of a Final Four comprised of only No. 16 seeds--the lowest-seeded teams in the tournament--is so small that it has a frequency of happening once every 13 trillion tournaments. (For perspective, if an entire tournament was played once every second, the lowest-seeded teams would only meet in the Final Four approximately once every 433,000 years.)

Copies of the paper are freely available to reporters by contacting the ASA. Visit http://bracketodds.cs.illinois.edu to see the model in action.

In a future where most things in our everyday life are connected through the internet, devices and sensors will need to run without wires or batteries. In a new article in Chemical Science, researchers from Uppsala University present a new type of dye-sensitised solar cells that harvest light from indoor lamps.

The Internet of Things, or IoT, refers to a network of physical devices and applications connected through the internet. It is estimated that by 2025, many facets of our lives will be mediated through 75 billion IoT devices, a majority of which will be located indoors. Broad installation of such IoT devices requires the devices to become autonomous, meaning that they should no longer need batteries or a grid connection to operate. To achieve this, it is crucial to identify a local low-maintenance energy source that can provide local power to IoT devices, especially in ambient conditions.

Towards this goal, a research team led by Marina Freitag, assistant professor at the Department of Chemistry, Uppsala University, has developed new indoor photovoltaic cells that can convert up to 34 per cent of visible light into electricity to power a wide range of IoT sensors. The team has designed novel dye-sensitised photovoltaic cells based on a copper-complex electrolyte, which makes them ideal for harvesting indoor light from fluorescent lamps and LEDs. The latest promising results establish dye-sensitised solar cells as leaders in power conversion efficiency for ambient lighting conditions, outperforming conventional silicon and solar cells made from exotic materials.

The research promises to revolutionise indoor digital sensing for smart greenhouses, offices, shelves, packages and many other smart everyday objects for the Internet of Things.

"Knowing the spectra of these light sources makes it possible to tune special dyes to absorb indoor light. While generating large amounts of energy, these indoor photovoltaics also maintain a high voltage under low light, which is important to power IoT devices," says Freitag.

In cooperation with the Technical University of Munich, the researchers have further designed an adaptive 'power management' system for solar-powered IoT sensors. In contrast to their battery-limited counterparts, the light-driven devices intelligently feed from the amount of light available. Computational workloads are executed according to the level of illumination, minimising energy losses during storage and thus using all light energy to the maximum of its availability. Combining artificial intelligence and automated learning, the solar cell system can thus reduce energy consumption, battery waste and help to improve general living conditions.

In the future, scientists expect that billions of IoT devices self-powered by indoor solar cells will provide everything from environmental information to human-machine and machine-machine communications. Such advanced sensors can further enhance the next wave of robotics and autonomous systems currently in development.

"Ambient light harvesters provide a new generation of self-powered and smart IoT devices powered by an energy source that is largely untapped. The combination of high efficiency and low cost with non-toxic materials for indoor photovoltaics is of paramount importance to IoT sustainability," says Freitag.

Researchers have reported a new material, pliable enough to be woven into fabric but imbued with sensing capabilities that can serve as an early warning system for injury or illness.

The material, described in a paper published by ACS Applied Nano Materials, involves the use of carbon nanotubes and is capable of sensing slight changes in body temperature while maintaining a pliable disordered structure - as opposed to a rigid crystalline structure - making it a good candidate for reusable or disposable wearable human body temperature sensors. Changes in body heat change the electrical resistance, alerting someone monitoring that change to the potential need for intervention.

"Your body can tell you something is wrong before it becomes obvious," said Seamus Curran, a physics professor at the University of Houston and co-author on the paper. Possible applications range from detecting dehydration in an ultra-marathoner to the beginnings of a pressure sore in a nursing home patient.

The researchers said it is also cost-effective because the raw materials required are used in relatively low concentrations.

The discovery builds on work Curran and fellow researchers Kang-Shyang Liao and Alexander J. Wang began nearly a decade ago, when they developed a hydrophobic nanocoating for cloth, which they envisioned as a protective coating for clothing, carpeting and other fiber-based materials.

Wang is now a Ph.D. student at Technological University Dublin, currently working with Curran at UH, and is corresponding author for the paper. In addition to Curran and Liao, other researchers involved include Surendra Maharjan, Brian P. McElhenny, Ram Neupane, Zhuan Zhu, Shuo Chen, Oomman K. Varghese and Jiming Bao, all of UH; Kourtney D. Wright and Andrew R. Barron of Rice University, and Eoghan P. Dillon of Analysis Instruments in Santa Barbara.

The material, created using poly(octadecyl acrylate)-grafted multiwalled carbon nanotubes, is technically known as a nanocarbon-based disordered, conductive, polymeric nanocomposite, or DCPN, a class of materials increasingly used in materials science. But most DCPN materials are poor electroconductors, making them unsuitable for use in wearable technologies that require the material to detect slight changes in temperature.

The new material was produced using a technique called RAFT-polymerization, Wang said, a critical step that allows the attached polymer to be electronically and phononically coupled with the multiwalled carbon nanotube through covalent bonding.

As such, subtle structural arrangements associated with the glass transition temperature of the system are electronically amplified to produce the exceptionally large electronic responses reported in the paper, without the negatives associated with solid-liquid phase transitions. The subtle structural changes associated with glass transition processes are ordinarily too small to produce large enough electronic responses.

A team of researchers from the University of Minnesota, University of Massachusetts Amherst, University of Delaware, and University of California Santa Barbara have invented oscillating catalyst technology that can accelerate chemical reactions without side reactions or chemical errors. The groundbreaking technology can be incorporated into hundreds of industrial chemical technologies to reduce waste by thousands of tons each year while improving the performance and cost-efficiency of materials production.

This research is published in Chemical Science, the premiere journal of the Royal Society of Chemistry.

In chemical reactions, scientists use what are called catalysts to speed reactions. A chemical reaction occurring on a catalyst surface such as a metal will accelerate faster than undesirable side reactions. When the primary reaction is much faster than every other side reaction, then the catalyst is good at selecting for the most valuable products. The side reactions are errors in chemistry control, and they result in significant generation of wasted material and economic loss.

Researchers at the Catalysis Center for Energy Innovation funded by the U.S. Department of Energy had a breakthrough when they realized they could design a new class of catalysts that greatly accelerated the primary surface reactions using waves. When the applied wave frequency and amplitude match up with characteristics of the primary chemistry, then that reaction becomes thousands of times faster than all other side reactions. The catalyst at these wave conditions essentially stops making any errors to side products.

"All chemical reactions have natural frequencies, like strings on a piano or a guitar," said Paul Dauenhauer, the lead author of the study and a Professor in the Department of Chemical Engineering and Materials Science in the University of Minnesota's College of Science and Engineering. "When we find that right frequency of a desired catalytic reaction, then the catalyst becomes almost perfect--the wasteful reactions almost completely stop."

The discovery has particular significance for the production of key chemicals in the energy, materials, food, and medical industries. The most important chemicals are manufactured at massive industrial scale such that even well-developed catalysts form some side products, generating thousands of tons of waste per year.

The researchers were able to broadly explain the relationship between different types of chemistries and the frequencies of surface waves that control catalyst errors.

"A molecule on a surface can go down several energy pathways, but the oscillating catalyst can almost completely control which pathway the molecule selects, including preventing molecules from moving along undesired energy conduits on the catalyst surface," said Alex Ardagh, the first author of the research paper and a postdoctoral research scholar at the University of Minnesota.

The discovery of highly selective, error-free catalysts builds on the previous development of dynamic catalytic theory developed by the same group. Conventional catalysts that exhibit optimal control over catalytic reactions have surface energies specific to a particular chemistry. However, the newer dynamic catalysts that change like a wave, oscillate binding energy between both stronger and weaker than the conventional surface energy.

"The transition from conventional to dynamic catalysts will be as big as the change from direct to alternating current electricity," said Professor Dionisios Vlachos, a professor at the University of Delaware and director of the Catalysis Center for Energy Innovation. "This has the potential to completely change the way we manufacture almost all of our most basic chemicals, materials, and fuels."

Over millennia, civilizations progressed through the Stone, Bronze, and Iron Ages. Now the time has come for quantum materials to change the way we live, thanks in part to research conducted at the Institut National de la Recherche Scientifique (INRS) and McGill University.

Professor Emanuele Orgiu, a researcher at INRS and a specialist in quantum materials. These materials are only a few atoms thick, but have remarkable optical, magnetic, and electrical properties. Professor Orgiu's research focuses on creating patterns on the surface of quantum materials in order to alter their properties.

"The shape of the drawings helps determine the properties imparted upon the surface," he explains.

His work has potential applications for (opto)electronic devices such as transistors and photosensors, but also for biosensing devices.

The quantum materials expert has just taken a big step forward by synthesizing macrocycles--large circular molecules--on a graphite surface. This material consists of a stack of graphene, a single atom-thick sheet of carbon. Graphene is considered a quantum material.

"Think of macrocycles as tiny Lego blocks. It's impossible to build a ring in solution, a homogeneous mixture in which the blocks are diluted. But you can do it if you put them on a table," said Professor Orgiu, lead author on a new study, the results of which were published online on February 18 in the journal ACS Nano.

In short, the postdoctoral researcher in Orgiu's group, Chaoying Fu, who is the first author of the study, has found a way to use macrocycles to draw molecular patterns on a material's surface.

"The macrocycles are deposited on the surface in solution and only the molecules are left once the liquid has evaporated. We can predict how they will fit together, but the alignment happens naturally through the interactions with neighbouring molecules and the surface," Professor Orgiu explains.

The study was conducted in collaboration with Dmitrii F. Perepichka, a professor in McGill's Department of Chemistry, whose expertise helped understand how certain molecules could arrange themselves on the surface of graphite.

"This is a great example of the power of a multidisciplinary approach where we combined organic synthesis and surface science. The level of control we achieved over the shape and the structure of synthesized molecules is quite remarkable," says Perepichka.

Orgiu said the shape and size of macrocycles made them the ideal candidate to draw on the graphite's surface.

"The advantage of these molecules is the large pores in their structure. We may eventually be able to use our macrocycles as a frame and decorate the pores with biomolecules that would promote biosensing properties of the surface. This is certainly one of our next steps for future projects."

An approach for developing light-emitting fabric based on typical ultrasheer pantyhose coated in a thin gold film may enable the development of softer, more wearable luminous clothing, researchers in Canada report March 4 in the journal Matter. The work addresses some of the limitations of existing light-emitting fabrics and, with effective power sources, could be developed into more functional designs for safety gear worn by first responders and nighttime construction workers, light-emitting athletic apparel, avante garde and everyday fashion, or wearable advertisements and logos.

"Users want light-emitting displays that are integrated into fabrics so that they are soft, lightweight, stretchable, washable, and wearable--just like ordinary clothing but with light-emitting panels that can illuminate the user or display graphics/information," says senior author Tricia Carmichael (@myatomicnumber), a professor of surface and materials chemistry at the University of Windsor.

However, designing wearable fabrics with a high-tech twist has proven challenging. Existing fabrication methods work well for rigid surfaces such as glass, silicon wafers, or plastics, but with their interwoven yarns designed to move and stretch, the textiles in clothing are far from rigid. As a result, current approaches to producing light-emitting apparel that involve sewing stiff diodes, wires, and optical fibres into textiles result in garments that lack the stretchability and softness of their non-luminous counterparts. They are also difficult to wash. Realizing the importance of fitting light-emitting devices within these flexible and stretchable structures in order to develop luminous fabrics that feel like any other garment, Carmichael and colleagues took a different approach.

"The lead author on the present paper, Yunyun Wu, was out shopping for fabrics for her research and had a eureka moment: why not use sheer fabrics as a solution for forming the transparent conductor, a crucial element of all light-emitting devices?" says Carmichael. "A second lightbulb moment came when we thought of pantyhose as an ideal material to build the new electrodes."

The researchers used electroless nickel-immersion gold metallization, a solution-based metal-deposition technique often used to make printed circuit boards that only deposits metal on the nylon and spandex fiber surfaces, to coat pantyhose with a highly conductive gold film only about 100 nm in thickness. They found that the coating process allowed the pantyhose fabric to retain its semi-transparency and stretchiness. Using this new fabrication technique, the researchers next created patterned light-emitting textiles with the smiley-face emoji, as well as a dynamic display comprised of seven rectangular segments that can rearrange to display numbers zero through nine.

Although gold can, of course, be pricey, Carmichael and colleagues believe its chemical stability and safety for skin make it an excellent choice for wearable materials. Since such a small quantity of gold (a coating 1,000 times thinner than a human hair) is needed to imbue textiles with the conductivity they need to light up, the researchers are not concerned about the metal's cost or other costs associated with scaling up production.

"We are optimistic about the ability to scale up the technology," says Carmichael. "The process we use to deposit the ultrathin gold coating on fabric fibers can be scaled up by increasing the volume of the plating solution, enabling processing of entire articles of clothing. We also use existing ultrasheer fabrics and thus do not require new textile manufacturing."

However, one major hurdle remains in the way of incorporating wearable light-emitting devices, in general, into everyday life: the ability to power them without bulky energy generators and storage systems.

"We are exploring the wide variety of textile architectures as an integral part of device electrode design to enable the seamless integration of brittle energy storage materials into textiles," says Carmichael.

DNA in a cell can normally be compared to spaghetti on one's plate: a large tangle of
strands. To be able to divide DNA neatly between the two daughter cells during cell division,
the cell organises this tangle into tightly packed chromosomes. A protein complex
called condensin has been known to play a key role in this process, but biologists had no
idea exactly how this worked. Until February 2018, when scientists from the Kavli Institute
at Delft University of Technology, together with colleagues from EMBL Heidelberg, showed
in real time how a condensin protein extrudes a loop in the DNA. Now, follow-up research
by the same research groups shows that this is by no means the only way condensin
packs up DNA. The researchers discovered an entirely new loop structure, which they call
the 'Z loop'. They publish this new phenomenon on 4 March in Nature, where they show,
for the first time, how condensins mutually interact to fold DNA into a zigzag structure.

More than just loops

'It started with the question of whether DNA
can be folded into a compact chromosome
by means of single loops, or whether there
is more to it,' says TU Delft postdoctoral
Dr. Eugene Kim. 'We wanted to see several
condensins at the same time. During the
experiments, we discovered an interesting
new form of folded DNA, which clearly differs
from a single loop, and which surprisingly also
occurs much more often than those loops.
We were able to figure out experimentally that
DNA is folded in a kind of zigzag structure.
We named these structures Z-loops, since
the DNA is folded in the form of the letter Z.'
The researchers mainly examined the
structure out of curiosity. 'It wasn't predicted
at all,' says Kim. We wondered: how is such
a structure made by two condensins, what is
the underlying molecular mechanism?

Zigzag structure through collaboration

Research leader Prof. Cees Dekker explains:
'The creation of a Z-shaped structure begins
when one condensin lands on DNA and makes
a single loop. Then, a second condensin
binds within that loop and starts to make its
own loop, creating a loop in a loop. When the
two condensins meet during their tug-of-war,
something surprising happens: the second
condensin hops over the first one and grabs
the DNA outside the loop, continuing its way
along the DNA. We were very surprised that
condensin complexes can pass each other.
This is completely at odds with current models,
which assume that condensins block each
other when they meet.'

Seeing the condensins at work

In cells, DNA is such a complex tangle that it
is very difficult to isolate and study the loop
extrusion process. The researchers therefore
visualized the loop formation in 1 DNA molecule
on a glass plate. They attached the two
ends of the DNA molecule to a surface and
stuck fluorescent labels to the DNA and the
condensin proteins. By then applying a flow in
the liquid, perpendicular to the molecule, the
researchers were able to make the DNA take
on a U-shaped form and bring it under the
microscope for imaging.

Medical relevance

This research is an important step in the
fundamental understanding of DNA in our
cells. It also has medical relevance. Problems
with the protein family to which condensin
belongs, the SMC proteins, are related to
hereditary disorders, such as Cornelia de
Lange Syndrome. Condensin is also crucial in
the organisation of chromosomes during cell
division; errors in this process can lead to cancer.
A better understanding of the underlying
molecular mechanisms is vital in the search
for the molecular origin of serious diseases.

The ability of the world's tropical forests to remove carbon from the atmosphere is decreasing, according to a study tracking 300,000 trees over 30 years, published today in Nature.

The global scientific collaboration, led by the University of Leeds, reveals that a feared switch of the world's undisturbed tropical forests from a carbon sink to a carbon source has begun.

Intact tropical forests are well-known as a crucial global carbon sink, slowing climate change by removing carbon from the atmosphere and storing it in trees, a process known as carbon sequestration. Climate models typically predict that this tropical forest carbon sink will continue for decades.

However, the new analysis of three decades of tree growth and death from 565 undisturbed tropical forests across Africa and the Amazon has found that the overall uptake of carbon into Earth's intact tropical forests peaked in the 1990s.

By the 2010s, on average, the ability of a tropical forest to absorb carbon had dropped by one-third. The switch is largely driven by carbon losses from trees dying.

The study by almost 100 institutions provides the first large-scale evidence that carbon uptake by the world's tropical forests has already started a worrying downward trend.

Study lead author Dr Wannes Hubau, a former post-doctoral researcher at the University of Leeds now based at the Royal Museum for Central Africa in Belgium, said: "We show that peak carbon uptake into intact tropical forests occurred in the 1990s.

"By combining data from Africa and the Amazon we began to understand why these forests are changing, with carbon dioxide levels, temperature, drought, and forest dynamics being key."

"Extra carbon dioxide boosts tree growth, but every year this effect is being increasingly countered by the negative impacts of higher temperatures and droughts which slow growth and can kill trees.

"Our modelling of these factors shows a long-term future decline in the African sink and that the Amazonian sink will continue to rapidly weaken, which we predict to become a carbon source in the mid-2030s."

In the 1990s intact tropical forests removed roughly 46 billion tonnes of carbon dioxide from the atmosphere, declining to an estimated 25 billion tonnes in the 2010s.

The lost sink capacity in the 2010s compared to the 1990s is 21 billion tonnes carbon dioxide, equivalent to a decade of fossil fuel emissions from the UK, Germany, France and Canada combined.

Overall, intact tropical forests removed 17% of human-made carbon dioxide emissions in the 1990s, reduced to just 6% in the 2010s.

This decline is because these forests were less able to absorb carbon by 33% and the area of intact forest declined by 19%, while global carbon dioxide emissions soared by 46%.

Senior author Professor Simon Lewis, from the School of Geography at Leeds, said: "Intact tropical forests remain a vital carbon sink but this research reveals that unless policies are put in place to stabilise Earth's climate it is only a matter of time until they are no longer able to sequester carbon.

"One big concern for the future of humanity is when carbon-cycle feedbacks really kick in, with nature switching from slowing climate change to accelerating it.

"After years of work deep in the Congo and Amazon rainforests we've found that one of the most worrying impacts of climate change has already begun. This is decades ahead of even the most pessimistic climate models.

"There is no time to lose in terms of tackling climate change."

To calculate changes in carbon storage the scientists measured the diameter and estimated the height of every individual tree in 565 patches of forest, returning every few years to re-measure them. By calculating the carbon stored in the trees that survived and those that died, the researchers tracked the changes in carbon storage over time.

After the final re-measurement, the study authors used a statistical model and trends in carbon dioxide emissions, temperature and rainfall to estimate changes in forest carbon storage until 2040.

By combining data from two large research networks of forests observations across Africa (AfriTRON) and Amazonia (RAINFOR) the authors show that the Amazon sink began weakening first, starting in the mid-1990s, followed by a waning of the African sink about 15 years later.

The continental difference arises from a combination of Amazon forests being more dynamic than those in Africa, and Amazon forests facing stronger climate impacts. Typical Amazonian forests are exposed to higher temperatures, faster temperature increases and more regular and severe droughts, than African forests.

Dr Hubau, Professor Lewis and their colleagues have spent years travelling to numerous remote field sites, including spending a week in a dug-out canoe to reach Salonga National Park in central Democratic Republic of Congo.

Dr Hubau said: "The ability of forests to slow climate change is a crucial element of understanding how the Earth system functions - particularly how much carbon is absorbed by the Earth and how much is released into the atmosphere.

"Continued on-the-ground monitoring of intact tropical forests is required to track the effects of accelerating environmental change. We need this more than ever, as our planet's last great tropical forests are threatened as never before."

The authors also highlight that tropical forests are still huge reservoirs of carbon, storing 250 billion tonnes of carbon in their trees alone. This storage is equivalent to 90 years of global fossil fuel emissions at today's level.

Study author Professor Bonaventure Sonké from the University of Yaounde I in Cameroon said: "The speed and magnitude of change in these forests suggests that climate impacts in the tropics may become more severe than predicted.

"African countries and the international community will need to seriously invest in preparation for ongoing climate change impacts in tropical regions."

Study author Professor Oliver Phillips, from University of Leeds, added "For too long the skills and potential of African and Amazonian scientists have been undervalued. We need to change this by ensuring their work is properly supported. It will fall to the next generation of African and Amazonian scientists to monitor these remarkable forests to help manage and protect them".

As tropical forests are likely to sequester less carbon than predicted, carbon budgets and emissions targets may need reassessing to account for this.

Professor Lewis said: "The immediate threats to tropical forests are deforestation, logging and fires. These require urgent action.

"In addition, stabilising Earth's climate is necessary to stabilise the carbon balance of intact tropical forests. By driving carbon dioxide emissions to net-zero even faster than currently envisaged, it would be possible to avoid intact tropical forests becoming a large source of carbon to the atmosphere. But that window of possibility is closing fast."

Modern society is working closer to the nanoscale than it realises. Breakthroughs and advances in developing and manipulating nanostructures have led to technological progress that not only drives imaging and sensing devices but also makes possible mainstays of modern life such as touch screens and high resolution LED displays.

A new review authored by international leaders in their field, and published in Nature, focuses on the luminescent nanoparticles at the heart of many advances and the opportunities and challenges for these technologies to reach their full potential.

Senior author, Professor Dayong Jin, says that by trying to understand how single nanoparticles behave scientists are asking very fundamental questions to develop tools that can be used to realise technological breakthroughs in diverse areas including personalised medicine, cyber security and quantum communication.

"The purpose of this field is to really understand the properties of these artificial atoms so that their properties can be controlled and tailored for the application we need," he says. Professor Jin is the Director of the University of Technology Sydney (UTS) Institute for Biomedical Materials & Devices (IBMD) and director of UTS-SUStech Joint Research Centre for Biomedical Materials & Devices.

The paper charts the rise of single molecule measurements and the rapid progress in optical microscopy that made it possible to 'see' the fluorescence of single photons and, thereby, the discovery of the underlying photophysics of the nanoscale. From quantum dots to carbon dots, fluorescent nanodiamonds and nanoparticles fabricated from obscure minerals such as perovskite - all promising tools for applications as diverse as imaging, biomarker detection and data storage.

But as the authors admit "the closer we pursue the perfection in nanoparticle design, the harder the challenges become".

Lead author Dr Jiajia Zhou from UTS IBMD, who specialises in building single particle optical spectroscopy to uncover the more unpredictable behaviour of nanoparticles, says that there is demand for smaller and more efficient nanoparticles with new desirable functions and characteristics.

"Especially for biomedical and intracellular applications such as molecular probes and sensors. Here we are talking about only a few nanometers in size where the challenge in forming uniform nanoparticles and controlling their shape, size and optical properties requires new knowledge about nanoparticle surface chemistry, for example," she says.

Still, in a very fast moving field the potential seems only to be limited by scientific imagination and, more likely, the ability of scientific and engineering disciplines to integrate knowledge and skills, the authors say.

"This paper is a large survey and highlights the need for a global effort and resources towards the fundamental research needed to keep pushing the boundaries of what is possible at the nanoscale, so society can benefit from the many emerging opportunities," Professor Jin says.

Professor Jin imagines a world where nanoscale tweezing is used to assemble hybrid nanoparticle- based devices and where biomedical signatures can be used to answer questions around an individual's response to drug therapies, all from one drop of blood.

"Everyday when people enjoy using smartphones and touch screens to send messages, and high resolution screen displays to view images and watch videos, they might forget where this technology comes from.

"These technologies may look like engineering projects but really they are the result of decades of research from scientists and students working 'in the dark' to answer fundamental questions about how nature works at the smallest of scales," he said.

Many health problems in the developed world stem from the disruption of a delicate metabolic balance between glucose production and energy utilization in the liver. Now Yale scientists report March 4 in the journal Nature that they have discovered the molecular mechanisms that trigger metabolic imbalance between these two distinct but linked processes, a finding with implications for the treatment of diabetes and non-alcoholic fatty liver disease (NAFLD).

The hormone glucagon, secreted by the pancreas, plays an essential role in metabolism. In times of food scarcity, it can jump-start the liver's production of glucose, an essential fuel for the brain, in a process called gluconeogenesis. In diabetes, which is marked by an excess of blood sugar, this process is disrupted.

Now a Yale team led by senior author Gerald Shulman and first author Rachel Perry, both endocrinologists, report that they have discovered how glucagon maintains metabolic balance between the production and use of energy in the liver.

"By applying novel methods to assess liver metabolism we were able to delineate the molecular mechanisms by which glucagon works," said Shulman, who is the George R. Cowgill Professor of Medicine and professor of cellular and molecular physiology.

Perry is assistant professor of cellular & molecular physiology and medicine.

Researchers have previously focused on glucagon in attempts to reduce elevated blood sugar in diabetes. But those experimental treatments led to potentially serious side effects, including buildup of liver enzymes indicating fatty liver disease.

The new research zeroed in on the role of calcium signaling within the mitochondria, the cell's energy-producing factory.

The authors discovered that a protein called inositol triphosphate receptor 1 (INSP3R1) regulates both gluconeogenesis and fat oxidation in the liver in response to glucagon. The group found that INSP3R1 influences gluconeogenesis by regulating calcium signaling within the cell and fat oxidation by influencing calcium signaling within the mitochondria.

"We identified mitochondrial calcium transport as a potential target to promote the good effects of glucagon to promote mitochondrial fat oxidation in the liver and reverse NAFLD without the bad effects of stimulating gluconeogenesis," Perry said.

When obese rodents were treated chronically with glucagon, the hormone reversed NAFLD and improved the body's response to insulin. However, when obese mice without INSP3R1 were chronically treated with glucagon, the hormone had no effect.

"These results provide new insights into glucagon biology and suggest that mitochondrial calcium transport, mediated by INSP3R1, may represent a novel target for therapies that aim to reverse NAFLD and type 2 diabetes," the authors conclude.

Ever since graphene's discovery in 2004, scientists have looked for ways to put this talented, atomically thin 2D material to work. Thinner than a single strand of DNA yet 200 times stronger than steel, graphene is an excellent conductor of electricity and heat, and it can conform to any number of shapes, from an ultrathin 2D sheet, to an electronic circuit.

Last year, a team of researchers led by Feng Wang, a faculty scientist in Berkeley Lab's Materials Sciences Division and a professor of physics at UC Berkeley, developed a multitasking graphene device that switches from a superconductor that efficiently conducts electricity, to an insulator that resists the flow of electric current, and back again to a superconductor.

Now, as reported today in the journal Nature, the researchers have tapped into their graphene system's talent for juggling not just two properties, but three: superconducting, insulating, and a type of magnetism called ferromagnetism. The multitasking device could make possible new physics experiments, such as research in the pursuit of an electric circuit for faster, next-generation electronics like quantum computing technologies.

"So far, materials simultaneously showing superconducting, insulating, and magnetic properties have been very rare. And most people believed that it would be difficult to induce magnetism in graphene, because it's typically not magnetic. Our graphene system is the first to combine all three properties in a single sample," said Guorui Chen, a postdoctoral researcher in Wang's Ultrafast Nano-Optics Group at UC Berkeley, and the study's lead author.

Using electricity to turn on graphene's hidden potential

Graphene has a lot of potential in the world of electronics. Its atomically thin structure, combined with its robust electronic and thermal conductivity, "could offer a unique advantage in the development of next-generation electronics and memory storage devices," said Chen, who also worked as a postdoctoral researcher in Berkeley Lab's Materials Sciences Division at the time of the study.

The problem is that the magnetic materials used in electronics today are made of ferromagnetic metals, such as iron or cobalt alloys. Ferromagnetic materials, like the common bar magnet, have a north and a south pole. When ferromagnetic materials are used to store data on a computer's hard disk, these poles point either up or down, representing zeros and ones - called bits.

Graphene, however, is not made of a magnetic metal - it's made of carbon.

So the scientists came up with a creative workaround.

They engineered an ultrathin device, just 1 nanometer in thickness, featuring three layers of atomically thin graphene. When sandwiched between 2D layers of boron nitride, the graphene layers - described as trilayer graphene in the study - form a repeating pattern called a moiré superlattice.

By applying electrical voltages through the graphene device's gates, the force from the electricity prodded electrons in the device to circle in the same direction, like tiny cars racing around a track. This generated a forceful momentum that transformed the graphene device into a ferromagnetic system.

More measurements revealed an astonishing new set of properties: The graphene system's interior had not only become magnetic but also insulating; and despite the magnetism, its outer edges morphed into channels of electronic current that move without resistance. Such properties characterize a rare class of insulators known as Chern insulators, the researchers said.

Even more surprising, calculations by co-author Ya-Hui Zhang of the Massachusetts Institute of Technology revealed that the graphene device has not just one, but two conductive edges, making it the first observed "high-order Chern insulator," a consequence of the strong electron-electron interactions in the trilayer graphene.

Scientists have been in hot pursuit of Chern insulators in a field of research known as topology, which investigates exotic states of matter. Chern insulators offer potential new ways to manipulate information in a quantum computer, where data is stored in quantum bits, or qubits. A qubit can represent a one, a zero, or a state in which it is both a one and a zero at the same time.

"Our discovery demonstrates that graphene is an ideal platform for studying different physics, ranging from single-particle physics, to superconductivity, and now topological physics to study quantum phases of matter in 2D materials," Chen said. "It's exciting that we can now explore new physics in a tiny device just 1 millionth of a millimeter thick."

The researchers hope to conduct more experiments with their graphene device to have a better understanding of how the Chern insulator/magnet emerged, and the mechanics behind its unusual properties.

New microfluidic process is the first that uses yield-stress fluids to create an undisturbed environment for experimentation, observation, and processing of biological and chemical reactions

The process can lead to new formulations for high-potency medicine such as cancer drugs, with improved quality and better results

The new method improves on traditional microfluidics and draws inspiration from embedded 3-D printing of structures inside support materials

Singapore, 4 March 2020 - Researchers from Singapore-MIT Alliance for Research and Technology (SMART), MIT's research enterprise in Singapore, and National University of Singapore (NUS) have developed a unique method for generating and processing fluid droplets under previously unattainable conditions. The discovery can be transformative in a range of scientific applications including the study of biological and chemical processes, and can pave the way for more exquisite and targeted pharmaceutical and consumer products.

The new process is explained in a paper titled "Embedded droplet printing in yield-stress fluids", published in the prestigious journal, Proceedings of the National Academy of Sciences of the United States of America (PNAS). The project is part of the National Research Foundation's (NRF) Intra-CREATE Collaborative Grant, which enabled the collaboration between researchers from the Campus for Research Excellence and Technological Enterprise (CREATE) partner institutions SMART and NUS.

Dr Arif Zainuddin Nelson, a researcher under SMART and Intra-CREATE's project "Advanced Manufacturing of Pharmaceutical Drug Products using Modular Microfluidic Processes", led the development of the new method, which is the first of its kind to take advantage of yield-stress fluids to create the ideal conditions for experimentation, processing or observation of various samples. Using the embedded droplet printing approach, the research team was able to produce suspended and perfectly spherical drug-laden particles. The new approach avoids malformations that are common in conventional methods, which produce particles that are ovoid in shape and result in poor flowability during manufacturing of medicines.

"We have developed a set of tools that allows us to observe and process many different applications under this unique method, including chemical and biological reactions," said NUS Professor Saif Khan, who is also part of the research team. "Pharmaceuticals is just one of the areas where this could produce transformative results, which is where our work is focused. We could change the way drugs are made, formulate them in a way that improves quality, revolutionise the way existing drugs are taken by patients, and envision entirely new drugs that cannot be made today."

The embedded droplet printing method, which can also be used to alter the size and dosage of existing drugs, would be particularly useful for designing high potency medicine that needs to be taken in very small doses, such as drugs taken by cancer patients. It can also lead to more tailored medicine as the new process would make it easier to develop small batches of specialised drugs for specific patients.

"With the exception of going into space to be in zero-gravity, this method is the only way to achieve an environment where various processes can be observed in such an isolated state," said Dr Nelson. "However, achieving a zero-gravity state is prohibitively expensive, and we have created a substantially easier and cheaper process to achieve a unique environment where chemical and biological processes are undisturbed by the outside forces."

For pharmaceuticals, Intra-CREATE's new microfluidic process would allow the capital costs for the formation of high-quality drugs to be circumvented, leading to potentially cheaper medication as well. The microfluidic process can also enable a range of other applications outside of the manufacturing of medicine, including:

Antibiotic testing: bacteria colonies can be cultured within each individual droplet. Different antibiotics and dosages can be tested on each droplet to quickly provide doctors and researchers with a view on potential antibiotics and cures. The unique environment allows manipulation of droplets in a way that could simulate infections

Embedded chemical reaction chambers: Microfluidic systems are able to handle a high throughput of small and precise volumes of reagents. The new process enables an improved environment for chemical reactions by removing solid boundaries, and can be used for nanoparticle production

Co-author of the research paper and Principal Investigator for SMART's Interdisciplinary Research Group, Critical Analytics for Manufacturing Personalised-Medicine (CAMP), MIT Professor Patrick Doyle said, "The new microfluidic process can be a gamechanger in a range of scientific experimentation, and the generality and wide impact of this method couldn't have been achieved without SMART and NUS working together."