The scientists used computer models to investigate how shallow-water tropical coral reef habitats might respond to climate change over the coming decades.

“If sea surface temperatures continue to rise, our models predict a large habitat collapse in the tropical Western Pacific which would affect some of the most biodiverse coral reefs in the world. To protect shallow-water tropical coral reefs, the warming experienced by the world’s oceans needs to be limited,” said Dr Elena Couce, lead-author of the study published in Geophysical Research Letters.

Shallow-water tropical coral reefs are amongst the most productive and diverse ecosystems on the planet but they are currently in decline due to increasing frequency of bleaching events, linked to rising temperatures and fossil fuel emissions.

The team applied statistical bioclimatic envelope models to determine whether limiting global temperatures via an artificial means called solar radiation geoengineering could help save the coral reefs.

Their findings suggest that the decline of suitable habitats for coral reefs could be slowed if geoengineering is effectively employed.

However, the researchers also discovered that over-engineering the climate could be detrimental as tropical corals do not favour overly-cool conditions. Solar radiation geoengineering also leaves a carbon dioxide problem known as ‘ocean acidification’ unchecked.

“The use of geoengineering technologies cannot safeguard coral habitat long term because ocean acidification will continue unabated. Decreasing the amount of carbon dioxide in the atmosphere is the only way to address reef decline caused by ocean acidification,” said Dr Couce

This was the first attempt to model the consequences of solar radiation geoengineering on a marine ecosystem and the researchers say that a lot more work is needed to fully understand the consequences of deliberate human intervention in the climate system.

The global researcher team led by Keck School of Medicine of the USC has for the first time uncovered unique cellular and molecular mechanisms behind tooth renewal in American alligators.

“Humans naturally only have two sets of teeth – baby teeth and adult teeth,” said USC pathology Professor Cheng-Ming Chuong. “Ultimately, we want to identify stem cells that can be used as a resource to stimulate tooth renewal in adult humans who have lost their teeth. But, to do that, we must first understand how they renew in other animals and why they stop in people.”

Most vertebrates can replace teeth throughout their lives, but human teeth are naturally replaced only once. This is despite the lingering presence of the dental lamina, a band of epithelial tissue which is crucial to tooth development.

The researchers used microscopic imaging techniques to discover that each alligator tooth is a complex unit of three components – a functional tooth, a replacement tooth, and the dental lamina – in different developmental stages.

Each tooth unit is structured to enable a smooth transition from dislodgement of the mature tooth to replacement with the new tooth. The team suggest that alligator dental laminae contain stem cells which allow new teeth to develop.

“Stem cells divide more slowly than other cells. The cells in the alligator’s dental lamina behaved like we would expect stem cells to behave,” said co-author Randall B. Widelitz, Associate Professor of Pathology at the Keck School of Medicine.

“We hope to isolate those cells from the dental lamina to see whether we can use them to regenerate teeth in the lab.”
The team also discovered the novel cellular mechanism by which the tooth unit develops in the embryos and the molecular signalling that speeds growth of replacement teeth when functional teeth are lost.

The study appears in Proceedings of the National Academy of Sciences.

Reference: Specialized stem cell niche enables repetitive renewal of alligator teeth

Published in Nature Nanotechnology, the researchers describe the world’s first graphene single-electron pump (SEP)which provides the speed of electron flow needed to create a new standard for electrical current based on electron charge.

“This paper describes how we have successfully produced the first graphene single-electron pump. We have work to do before we can define the amphere, but this is a major step towards that goal,” said Malcolm Connolly, a research associate based in the Semiconductor Physics group at Cambridge.

The international systems of units (SI) comprises seven based units (the metre, kilogram, second, Kelvin, ampere, mole and candela). These should be stable over time and universally reproducible which requires definitions based on fundamental constants of nature which are the same wherever you measure them.

However, the present definition of the ampere is vulnerable to drift and instability which is not sufficient to meet the accuracy needs of present and future electrical measurement.
SEPs create flow of individual electrons by shuttling them into a quantum dot and emitting them one at a time at a well-defined rate, pumping them quickly to generate a sufficiently large current.

Previous SEPs were made from aluminium and were very accurate, but pumped electrons too slowly for making a practical current standard. Graphene’ s unique semi metallic two-dimensional structure has just the right properties to let electrons on and off the quantum dot very quickly, creating a fast enough electron flow to create the current standard.

The researchers still need to optimise the material and make more accurate measurements, but the paper marks a major step forward in the road towards using graphene to redefine the ampere.
“We have shown that graphene outperforms other materials used to make this style of SEP. It is robust, easier to produce and operates at higher frequency. Graphene is constantly revealing exciting new applications and as our understanding of the material advances rapidly we seem able to do more and more with it,” said Connolly.

Reference: Gigahertz quantized charge pumping in graphene quantum dots

Sequencing the flesh-eating water plant’s genome, which has 80 million DNA base pairs, has revealed that 97% of it consists of genes and small pieces of DNA that control these genes. The researchers suggest the plant has been deleting noncoding “junk” DNA from its genome over many generations.

“The big story is that only 3% of the bladderwort’s genetic material is so-called junk DNA,” said Victor Albert, Professor of Biological Sciences from the University of Buffalo who co-directed the study detailed in Nature. “Somehow this plant has purged most of what makes up plant genomes. What that says is that you can have a perfectly good multicellular plant with lots of different cells, organs, tissue types and flowers, and you can do it without the junk. Junk is not needed.”

The bladderwort’s genome suggests that having a myriad of noncoding DNA isn’t crucial for complex life. U. gibba lives in aquatic habitats and has developed highly specialised hunting methods. To capture its prey, the plant pumps water from tiny chambers, turning each into a vacuum that can suck in and trap unsuspecting creatures.
A recent series of papers from ENCODE have begun to offer an explanation to the mystery of noncoding DNA’s existence, suggesting it plays a role in biochemical functions such as regulation and promotion of DNA conversion into RNA in order to make proteins.

However, the researchers behind the bladderwort study argue that organisms may not possess genetic junk for reasons of benefit. They suggest that some species may simply have an inherent, mechanistic bias toward deleting a lot of noncoding DNA, while others have a built-in bias to do the opposite.

U. gibba has a miniscule number of base pairs compared to other complex plants, such as its tomato relative (780 million) which the researchers say the deleting of noncoding DNA accounts for.
The small size of the bladderwort genome is even more surprising considering the species has undergone three complete genome doublings since its evolutionary lineage split from that of tomato.

“This surprisingly rich history of duplication, paired with the current small size of the bladderwort genome, is further evidence that the plant has been prolific at deleting nonessential DNA, but at the same time maintaining a functional set of genes similar to those of other plant species,” said study leader Professor Herrera-Estrella, director of the LANGEBIO in Mexico.

Reference: (Ibarra-Laclette et al 2013) Architecture and evolution of a minute plant genome

Using advanced biochemical analysis and X-ray imaging techniques at Diamond Light Source, researchers from University of York, University of Portsmouth and the National Renewable Energy Laboratory in the USA have determined the structure and function of a key enzyme in the gribble’s stomach that enables it to break down wood.

“Gribbles used to be the scourge of the navy,” Dr John McGeehan, a structural biologists from the University of Portsmouth team, told Laboratory News. “The creatures historically attacked the timber hulls of seafarer’s ships and continue to destroy seaside piers like the ones in Portsmouth.”

It has been known for a long time that gribbles are ferocious gobblers of wood, but it was previously assumed that microbes in their gut provided the enzymes needed to perform this task. However, the researchers discovered to their surprise that the gribble possesses a sterile stomach which means it uses its own enzymes to break the polysaccharides in wood into simple sugars.

“Similar enzymes have been found in wood-degrading fungi, but this is totally new. It’s the first cellulase that’s ever been found in an animal,” said McGeehan.

The team transferred the genetic blueprint of the gribble’s cellulase to an industrial microbe that could produce it in large quantities. They were then able to make crystals of the enzyme and transport them to Diamond Light Source, the UK’s National Synchrotron Science Facility.

There, the researchers fired an intense beam of X-rays at the crystals to generate a series of images that can be transformed into 3D models. The team at the National Renewable Energy Laboratory then used powerful supercomputers to model the enzyme in action to reveal how the cellulose chains of wood are digested into glucose.

“Looking at the enzyme’s 3D shape revealed some unexpected results,” said McGeehan. “The enzyme skeleton looks very similar to cellulases found in fungi, but its surface is completely different. We think this is because the enzyme evolved in sea water and can therefore survive very harsh conditions (high salt concentrations). This means the enzyme has real biotech applications.”

The ultimate aim is to reproduce the effect of the gribble’s enzyme on an industrial scale in a bid to create sustainable liquid biofuels.

“The biotech industry needs to copy what nature has already done and I think this is quite a timely discovery considering the country’s rising energy bills. A real focus is needed on producing sustainable energy and this little gribble could be a game changer,” said McGeehan.

Reference: Structural characterization of the first marine animal Family 7 cellobiohydrolase suggests a mechanism of cellulase salt tolerance

The mechanism is known as a ‘dynamo’ and builds on a solution to a reduced set of equations first proposed in the 1950s which could explain the Sun’s regular oscillation, but which appears to break down when applied to objects with high electrical conductivity.

“Previously, dynamos for large, highly conducting bodies such as the Sun would be overwhelmed by small-scale fluctuations in the magnetic field. Here, we have demonstrated a new mechanism involving shear flow, which serves to damp these small-scale variations, revealing the dominant large-scale pattern,” said Professor Steve Tobias, from the University of Leeds’ School of Mathematics and co-author of the research published in Nature.

Scientists have known since the 18th century that the Sun regularly oscillates between periods of high and low solar activity in an 11-year cycle, but have been unable to fully explain how the cycle is generated.

In recent years, it has become more and more important to understand the Sun’s magnetic activity as changes in its magnetic field are responsible for ‘space weather’ phenomena such as solar flares and coronal mass ejections. When this weather heads in the direction of Earth it can damage satellites, endanger astronauts on the International Space Station and cause power grid outages on the ground.

The new mechanism takes into account the ‘shear’ effect of mass movement of the ionised gas (plasma) which makes up the Sun and does so in the extreme parameter regime that is relevant to astrophysical bodies.

Additionally, the mechanism, which was developed through simulations using the high-performance computing facilities at Leeds, could be used to describe other large, spinning astronomical bodies with large-scale magnetic fields, like galaxies.

“The fact that it took 50 years and huge supercomputers shows how complicated the dynamo process really is,” said Professor Fausto Cattaneo, from the University of Chicago’s Department of Astronomy and Astrophysics.

 Reference: Shear-driven dynamo waves at high magnetic Reynolds Number 

Five subjects took part in the study, published in the Journal of Neural Engineering. The participants were each able to successfully control the four-blade flying robot (quadcopter) quickly and accurately for a sustained amount of time using only their thoughts.

“Our study shows that for the first time, humans are able to control the flight of flying robots using just their thoughts sensed from a non-invasive skull cap,” said Bin He, lead author of the study and Biomedical Engineering Professor in the University’s College of Science and Engineering. “It works as good as invasive techniques used in the past.”

The method is called electroencephalography (EEG), which is a unique brain-computer interface that records the electrical activity of the volunteers’ brains through a skull cap that contains 64 electrodes.

This study is the first to use functional MRI and EEG imaging to map where in the brain neurons are activated when someone imagines movements.

It is the geography of the brain’s motor cortex (the area of the cerebrum that governs movement which is responsible for the interface’s functionality say the researchers.

When we move or think about a movement, neurons in the motor cortex produce a series of tiny electric currents. When we think about a different movement, a new assortment of neurons is activated. It is in sorting out these assortments that has laid the groundwork for the system used at Minnesota.

During the study, the participants faced away from the quadcopter and were asked to imagine using their right hand, left hand and both hands together to move the flying robot.

The subjects were positioned in front of a screen that relayed images of the quadcopter’s flight through an on-board camera. Brain signals were recorded by the EEG cap and sent to the robot over Wi-Fi.

This new research builds upon previous research conducted in He’s laboratory where participants were able to control a virtual helicopter on a computer screen.

“Our next step is to use the mapping and engineering technology we’ve developed to help disabled patients interact with the world,” He said. “It may even help patients with conditions like autism or Alzheimer’s disease or help stroke victims recover. We’re now studying some stroke patients to see if it’ll help rewire brain circuits to bypass damaged areas.”

Reference: Quadcopter control in three-dimensional space using a noninvasive motor imagery-based brain–computer interface

The discovery, detailed in Nature, could advance the search for a new fundamental force in nature that might explain why the Big Bang created more matter than antimatter.

“If equal amounts of matter and antimatter were created at the Big Bang, everything would have annihilated, and there would be no galaxies, stars, planets or people,” said Tim Chupp, a University of Michigan Professor of Physics and Biomedical Engineering and co-author of the study.

Antimatter particles have the same mass but opposite charge from their matter counterparts. Antimatter is rare in the known universe, but when matter and antimatter particles collide, they mutually destruct.

Physicists have long been searching for signs of a new force of interaction that might explain the matter-antimatter discrepancy.

Most nuclei are shaped like rugby balls but pear-shaped nuclei are lop-sided because positive protons are pushed away from the centre of the nucleus by nuclear forces that are fundamentally different from spherically symmetric forces like gravity.

Until now, it has been hard to experimentally observe pear-shaped nuclei, but a technique at ISOLDE facility at CERN has been used successfully to study the shape of the short-lived isotopes Radon 220 and Radium 224.

The atom beams were accelerated and smashed into targets of nickel, cadmium and tin. In this method, the relative motion of the heavy accelerated nucleus and the target nucleus creates an electromagnetic impulse that excites the nuclei. Physicists can understand nuclear shape by studying the details of the excitation process.

In this study, the nuclei produced gamma rays that flew out in a distinctive pattern that revealed a pear-shape.

“Our expectation is that the data from our nuclear physics experiments can be combined with the results from atomic trapping experiments measuring EDMs to make the most stringent tests of the Standard Model, the best theory we have for understand the nature of the building blocks of the universe,” said University of Liverpool Professor Peter Butler who led the study.

Reference: Nuclear physics: Exotic pear-shaped nuclei

The study, which is published in Nature Communications, suggests that engineering atomic-scale quantum states on the surface of silicon may be an important step towards creating a range of devices at the single-atom limit.

Dr Steven Schofield who led the study told Laboratory News: “There are many reasons why it is desirable to build systems of individual atoms and observe the interactions between them. These range from furthering our understanding of the physics that governs individual atoms, molecules and solids, to the potential to build novel electronic devices that exploit quantum mechanical phenomena for their operation.”

Advances in atomic physics now mean single ions can be brought together to form quantum coherent states. However, in order to build large numbers of coupled atomic systems (for processes such as quantum computing), it is desirable to develop the ability to construct coupled atomic systems in the solid state such as silicon crystal, since these are very stable, can be made extremely pure and can be integrated with existing technology.

The team exposed a silicon surface to a source of atomic hydrogen – created by heating H₂ molecules to 1500 °C. This resulted in a surface where every silicon atom had a single H atom attached to it.

“We create defects by removing individual H atoms – an electron-stimulated desorption process using the highly confined electron beam from the scanning tunnelling microscope tip,” explained Schofield. “We have created systems of dangling bonds where each dangling bond is located on a next-nearest silicon atom. The separation between them is about 0.78 nanometres.”

When these atomic defects are coupled together they produce extended quantum states that resemble artificial molecular orbitals – each structure exhibits multiple quantum states with distinct energy levels.

“The next step is to replicate these results in other material systems, for example, using substitution phosphorus atoms in silicon, which holds particular interest for quantum computer fabrication,” said Schofield.

Reference: Quantum engineering at the silicon surface using dangling bonds

Carotenoids, the pigments that give carrots their orange colour, are also fundamental for photosynthesis. Their role in absorbing light and transferring it to chlorophyll to be converted to energy has been known for a long time but the exact mechanism for this process has remained poorly understood.

Professor Richard Cogdell, Director of the Institute and Hooker Professor of Botany at Glasgow, said: “The energy transfer processes involving carotenoids in natural light-harvesting systems have been intensively studied for the last 60 years, yet certain details of the underlying mechanisms remain controversial. Our work really clears up this mystery.”

The researchers demonstrated that a special ‘dark state’ of the carotenoid – a hidden level not used for light absorption at all – acts as a mediator to help pass the energy it absorbs very efficiently to a chlorophyll pigment.

“This is an example of how nature exploits subtleties that we would likely overlook if we were designing a solar energy harvester,” said Greg Scholes, the D.J. LeRoy Distinguished Professor in the Department of Chemistry at the University of Toronto.

Scholes and colleagues aimed to characterise in more detail the whole sequence of quantum mechanical states of carotenoids.

Using a technique called broadband two-dimensional electronic spectroscopy, the researchers were able to measure the electronic structure and its dynamics in atoms and molecules of light-harvesting proteins from purple bacteria.

The findings revealed a signature of a special ‘dark-state’ where the carotenoid cannot absorb or emit light which plays an important role in mediating energy flow from carotenoid to chlorophyll.

The existence of ‘dark-states’ has been speculated about for decades. The team’s work published in Science is the clearest evidence to date of their existence and importance.

“It is utterly counter-intuitive that a state not participating in light absorption is used in this manner. It is amazing that nature uses so many aspects of a whole range of quantum mechanical states in carotenoid molecules, more, and puts those states to use in such diverse ways” said Scholes.

E. E. Ostroumov, R. M. Mulvaney, R. J. Cogdell, G. D. Scholes. Broadband 2D Electronic Spectroscopy Reveals a Carotenoid Dark State in Purple Bacteria.