Rotating resonator creates a one-way street for light

29 Jun 2018

One-way system: researchers find new way to stop light from propagating in the wrong direction. (Courtesy: Shutterstock/Shibiko)

An optical device that uses mechanical rotation to allow light to propagate in one direction along a fibre, but not in the opposite direction has been built by an international team of researchers. The device could find use in optical circuits, where it is very difficult to prevent light from propagating in unwanted directions. However, practical applications may be difficult to achieve.

The idea of using mechanical rotation to allow waves to travel in one direction, but not in the opposite direction, was first developed in 2014 by Andrea Alú and colleagues at the University of Texas at Austin. They placed a fluid into a circular cavity and stirred it so the fluid rotated. Sound waves travelling around the cavity in one direction were pushed along by the fluid, whereas waves travelling in the opposite direction were held back. As a result, the resonant frequency of the cavity was different for sound moving in opposite directions. By judiciously choosing the rotation speed of the fluid, the researchers could ensure that sound waves at a chosen frequency could only travel in one direction around the cavity.

Maxwell model optimizes motion energy harvesters

29 Sep 2018

Maxwell-based models

From wind and wave energy to machine vibrations and the simple act of walking down a street, mechanical movement of any kind can be fuel with the aid of triboelectric nanogenerators (TENGs). Now researchers at the University of Surrey in the UK led by S. Ravi P. Silva have used a description of TENG behaviour based on the fundamental equations of electromagnetism – the Maxwell equations – to optimize TENG designs to maximize their efficiency.

Michio Kaku String Theory & Higher Dimensions 2018 update

         



Michio Kaku String Theory & Higher Dimensions 2018 update



29/9/2018

US, India and Saudi Arabia could be biggest climate losers

27 Sep 2018 Liz Kalaugher

(Courtesy: Shutterstock/kwest)

The US, India and Saudi Arabia are the three countries with the most to lose from climate change. That’s according to the first study to quantify the social cost of carbon – a measure of the economic harm resulting from carbon dioxide emissions – on a country by country basis.

“Our analysis demonstrates that the argument [in the US] that the primary beneficiaries of reductions in carbon dioxide emissions would be other countries is a total myth,” says Kate Ricke of the University of California San Diego, US. “We consistently find, through hundreds of uncertainty scenarios, that the US always has one of the highest country-level social costs of carbon. It makes a lot of sense because the larger your economy is, the more you have to lose.”

Hotter planet faces more killer heat

28 Sep 2018

Smoke inhalation is the main way that wildfires can kill. Image: By Nerval, via Wikimedia Commons (public domain)

Once again, researchers have confirmed that limiting global warming will save lives by reducing the impact of killer heat.

An international team has checked predictions for heat-related deaths against some of the global average temperatures likely later this century, to issue this warning: it will be a safer world if temperatures creep up by only 1.5°C over historic levels. Fewer people will die in the ever more intense heat extremes that will go with average global temperature rises.

Schrödinger’s cat as you’ve never seen it before

27 Sep 2018 Tushna Commissariat

Taken from the September 2018 issue of Physics World

Regular readers of the magazine will be familiar with “Lateral Thoughts” – Physics World’s long-running column of humorous or otherwise offbeat essays, puzzles, crosswords, quizzes and comics, all written by our readers – that appears on the back page each month. This month, siblings Eugenia Viti and Ivan Viti have crafted a comic that takes a wry look at the physics of Schrödinger’s cat. Eugenia is a cartoonist, illustrator and writer living in Chicago. Follow her on instagram (ayokdit) to see how much pizza she eats. It’s a lot. Ivan has a PhD in physics and is currently working as a postdoctoral researcher at the University of Notre Dame, Indiana. He lives with his wife, two cats, two dogs and one goldfish. And once you’ve had your fill of cats, take a look at their other special comic, on the the theme of time – this one involves dogs.

US invests $249m in quantum information science as White House unveils strategic overview

28 Sep 2018 Hamish Johnston

Industrial action: IBM’s 50-qubit quantum computer. (Courtesy: IBM)

A National Strategic Overview for Quantum Information Science has been released by the US National Science and Technology Council (NSTC), which coordinates the science and technology policy of the President of the US. The overview identifies several key policy actions designed to keep the US at the forefront of quantum-technology development.

In related announcements, two science funding agencies in the US – the Department of Energy and the National Science Foundation — have committed a total of $249m to 118 research projects related to quantum information science (QIS).

QIS is currently making the transition from the lab to industry and includes a range of technologies including quantum computing, cryptography and sensing that take advantage of the fundamental principles of quantum mechanics.

Personalized UV sensors monitor sun exposure

28 Sep 2018 Tami Freeman

Prototypes of the skin tone-specific UV sensors. (Courtesy: RMIT University)

Researchers from RMIT University in Australia have developed an ink that changes colour when exposed to different types of ultraviolet (UV) radiation. They used the ink to create low-cost wearable sensors for monitoring UV exposure throughout the day. Such sensors could help people manage vitamin absorption while avoiding sun damage (Nature Communications9 3743).

Humans need a modest level of sun exposure to maintain healthy levels of vitamin D. Excessive exposure, however, can cause health problems. UVA (315–400 nm) radiation penetrates deep into the skin and results in skin aging and wrinkling. UVB (280–315 nm), meanwhile, is particularly effective at damaging DNA. Too much UVB exposure can cause sunburn, which increases the likelihood of developing skin cancer and cataracts.

20 ΤΡΟΦΙΜΑ ΠΟΥ ΑΠΟΦΡΑΣΣΟΥΝ ΜΕ ΦΥΣΙΚΟ ΤΡΟΠΟ ΤΙΣ ΑΡΤΗΡΙΕΣ

20 ΤΡΟΦΙΜΑ ΠΟΥ ΑΠΟΦΡΑΣΣΟΥΝ ΜΕ ΦΥΣΙΚΟ ΤΡΟΠΟ ΤΙΣ ΑΡΤΗΡΙΕΣ

Αποκαταστήστε την καλή λειτουργία της καρδιάς σας και διατηρήστε την υγιή με μια ποικιλία τροφών που έχουν την ικανότητα να αποφράσσουν και να καθαρίζουν τις αρτηρίες από τη συσσώρευση πλάκας, να μειώνουν την αρτηριακή σας πίεση, και να μειώνουν τις φλεγμονές των αγγείων, τους κύριους ενόχους της καρδιαγγειακής νόσου.

Πολλές από τις τροφές που παραθέτουμε σε αυτή τη λίστα περιέχουν ωφέλιμα λιπαρά, αντιοξειδωτικά, και διαλυτές φυτικές ίνες που κάνουν καλό, όχι μόνο στην καρδιά σας, αλλά σας βοηθούν να διατηρείτε υγιή το δέρμα, τα μαλλιά, την παραγωγή ορμονών και την λειτουργία του πεπτικού σας συστήματος. Με τις τροφές αυτές θα αισθάνεστε ευεξία, θα έχετε περισσότερη ενέργεια, και θα βελτιώσετε την υγεία της καρδιάς σας χωρίς τη χρήση χημικών ουσιών που προκαλούν παρενέργειες.

Cool polymer paint saves on air conditioning

27 Sep 2018 Anna Demming

The porous polymer passive daytime radiative cooling coating reflects sunlight and emits heat

Air conditioning accounts for 10% of global energy consumption. Now researchers at Columbia University and Argonne National Laboratory in the US have produced a polymer “paint” capable of cooling surfaces to around 6 °C below ambient temperatures without using any energy at all. Used in combination with conventional air conditioning, it could allow significant reductions in the time these units are switched on, as well as providing some cooling relief in areas where air conditioning is not so widely available.

The approach uses a solution process at room temperature to produce a film of a polymer with nanometre- and micrometre-sized air voids trapped inside.

Memristive metal-organic films made easy

27 Sep 2018 Belle Dumé

Highly conductive and memristive metal-organic films

Researchers at the Universidad Autónoma de Madrid in Spain have developed a new, simple, one-pot method to make highly conductive metal-organic ultrathin films that are both flexible and mechanically strong. The films can be produced over areas as large as mm2, are smooth, highly transparent and behave as memristors at low frequencies. They might be used in a wide variety of flexible electronics applications in the future, including health-monitoring devices.

AI algorithm produces synthetic brain MR images

27 Sep 2018

© AuntMinnieEurope.com

An artificial intelligence (AI) algorithm can produce synthetic brain MR images, solving a number of challenges in training AI algorithms, according to research presented at the International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI) in Granada, Spain.

Researchers from NVIDIA, Massachusetts General Hospital and Brigham and Women’s Hospital in Boston, and the Mayo Clinic in Rochester, MN, have trained a type of AI algorithm called a generative adversarial network (GAN) to generate synthetic abnormal brain MR images. These synthetic images could be used to augment a small dataset or even on their own to train a deep-learning algorithm, according to Hoo-Chang Shin, a senior research scientist at NVIDIA.

Examples of synthetic brain MR images generated by the GAN. The first row depicts the real images on which the synthetic tumours were based. (Courtesy: NVIDIA).

“We showed that you don’t have to have access to a large number of patient images,” he told AuntMinnie.com. “You can generate a lot of synthetic images and train your AI on these synthetic images — with only a handful of real images to fine-tune the pretrained AI — and achieve almost the same performance as if you had trained on a large number of real data.”

Shape-shifting red blood cells respond to shear forces

26 Sep 2018

Going with the flow: artist's impression of red blood cells flowing through a blood vessel. (Courtesy: iStockphoto.com/spanteldotru)

The shape of red blood cells depends on where they are in the body and now researchers in Germany and France have used microfluidics in combination with numerical simulations to gain important new insights into how this shape-shifting occurs.

Red blood cells are disk-like objects with diameters of about 8 microns and account for almost half of the blood’s composition. At rest, the cells have a symmetric biconcave-disk shape that is thicker at the edge than in the centre (see figure).

They are not rigid particles and comprise a liquid cytoplasm that is encapsulated by a membrane, making the overall cell structure flexible. As the cell travels through the body, it flows through wide arteries and veins, but can also negotiate narrow vessels. All the while, the cells are immersed in relatively thick and viscous blood plasma – which can affect their shape.

Collective electron excitations break down quantum Hall effect in graphene

26 Sep 2018 Belle Dumé

Bernard Plaçais

The quantum Hall effect (QHE) is one of the most important effects being studied by solid-state physicists today. Measuring the limits at which it breaks down is extremely important – not only for fundamental physics but also for applying the effect as a resistance standard for redefining the kilogram. Researchers in France have now found that collective excitations of interacting electrons are responsible for the onset of the breakdown of the QHE in bilayer graphene at high electric fields and they have even calculated the “Landau velocity” at which this happens. The new result lends weight to the idea that the long-held single-electron picture is not a realistic description of the QHE. The breakdown mechanism also looks very much like what happens in superconductors at the limit at which correlated electron pairs (responsible for the supercurrent in these materials) break apart and at the point at which superfluidity collapses in systems like liquid helium.

Colour-changing contact lenses could improve drug delivery

26 Sep 2018 Rebecca Fong

Photonic crystal contact lenses allow controlled and monitored drug release. Credit: Deng

Functional contact lenses are an exciting method of drug delivery to the eye, but have so far been limited by difficulties in controlling drug release and monitoring this release in situ. Now Jingzhe Deng and his groups at China Pharmaceutical University and Southeast University, China show that a combination of molecular imprinting and structural colour could provide a solution.

The researchers report (ACS Applied Materials & Interfaces) a contact lens containing specific drug-binding sites with the capability of sustained release over time. Furthermore, they show that the device can also self-report this drug-delivery process. As the binding and release of the target molecule to the contact lens results in a change of the refractive index of the matrix, drug release can be observed directly as a colour change of the lens.

pH responsive photonic crystals

A promising new vaccine against melanoma

26 Sep 2018 Samuel Vennin

Senior author Bruce Beutler from the University of Texas Southwestern Medical Center.

Researchers from the University of Texas and the Scripps Research Institute have demonstrated that adding a new adjuvant, Diprovocim, to a cancer vaccine can draw cancer-fighting cells to the tumour site and boost the immune response (PNAS10.1073/pnas.1809232115).

As cancer spreads, it inhibits the activity of T cells, the immune cells responsible for fighting off cancerous cells. Immunotherapy aims to harness the immune system to combat tumours and lately, cancer vaccines have been investigated as a potential trigger for this reaction. The vaccines are usually associated with adjuvants, molecules that are added to enhance the immune response to some specific antigens.

Once a physicist: Noel Bakhtian

26 Sep 2018 Tushna Commissariat

Taken from the September 2018 issue of Physics World

Noel Bakhtian is director of the Center for Advanced Energy Studies (www.caesenergy.org) and a member of the senior leadership team at the US Department of Energy’s Idaho National Laboratory. She was recently featured by Business Insider magazine as one of the 20 most powerful female engineers.

What sparked your initial interest in physics?

In my first ever physics class, in high school, I loved learning that everyday concepts, such as velocity and acceleration, electricity and magnets, gravity, friction and sound, all had equations that described their behaviour. I loved the logic of it all and how physics and mathematics were really the underlying foundation of everything one encountered in the physical world. Based on that and my love of all things space (from NASA and sky‑gazing to Star Wars), I attended a residential summer camp during high school called the Summer Science Program, where my interest and understanding of physics took a quantum leap. We took graduate‑level courses to learn everything from spherical trigonometry to computer coding, which we used to write our own software to calculate the orbital parameters of asteroids that we were tracking with telescopes. My experience during this collaborative, hands-on, magical summer left me with no other choice than to pursue a physics-based degree when I got to college.

What did your physics and engineering degrees focus on?

quantum computing in the cloud

quantum computing in the cloud

06 Jul 2018

This article first appeared in the 2018 Physics World Focus on Computing

Quantum computing devices are becoming more powerful, but until recently only a handful of specialists could tap into their capabilities. Thomas Papenbrock, Pavel Lougovski and Martin Savage describe how commercially available cloud-based quantum computing services could open the field to new users

Quantum computers – devices that use the quantum mechanical superposition principle to process information – are being developed, built and studied in organizations ranging from universities and national laboratories to start-ups and large corporations such as Google, IBM, Intel and Microsoft.

THE RIDDLE OF ULTRA - HIGH ENERGY COSMIC RAYS

THE RIDDLE OF ULTRA - HIGH ENERGY COSMIC RAYS

31 Jul 2018

Taken from the August 2018 issue of Physics World under the headline "Meet the ultras"

Ultrahigh-energy cosmic rays are the most energetic and rarest of particles in the universe – and also one of the most enigmatic. Benjamin Skuse reveals how cosmic-ray mysteries are continuing to test our understanding of high-energy physics

Far, far away, something – somewhere – is creating particles with crazy amounts of energy. Whatever they are or wherever they’re from, these particles can be anything between 1018 eV and 1020 eV. Given that the top particle energy at CERN’s Large Hadron Collider is about 1013eV, some of these particles are a million times more energetic than anything we can fashion at the most powerful particle accelerator on the planet. Quite simply, they’re the most energetic particles ever seen in nature.

Neuromodulation helps paralysed man take independent steps

25 Sep 2018 Tami Freeman

A patient with complete lower limb paralysis can independently step again following a combination of electronic spinal cord stimulation and rehabilitation therapy, reports a study from Mayo Clinic and UCLA (Nature Medicine 10.1038/s41591-018-0175-7).

Treadmill stepping

Treadmill stepping with and without epidural electrical stimulation. (Courtesy: Zhao et al; Mayo Clinic; Nature Medicine)

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Severe spinal cord injuries can functionally disconnect the higher brain centres that guide movement from the spinal cord circuitry, located below the injury, that interacts with skeletal muscle – causing chronic paralysis. In this study, the subject had injured his spinal cord in the middle of his back in a snowmobile accident.

Superconducting and diamond qubits get a boost

25 Sep 2018

Quantum schemes: are physicists are getting closer to making a practical quantum computer? (Courtesy: iStock/Bellenixe)

Important challenges in creating practical quantum computers have been addressed by two independent teams of physicists in the US. One team has created a new way of reading-out superconducting quantum bits (qubits), while the other has come-up with a new way to get spin qubits in diamond to interact with each other.

Any viable quantum computer needs isolated quantum states that can store qubits of information for relatively long periods of time. It must also be possible for these qubits to interact with each other at appropriate times so that the information can be processed and the results read-out. It is these often-conflicting requirements that made it very difficult to create a practical quantum computer

Expert opinions vary on earthquake risk from enhanced geothermal systems

25 Sep 2018

(Courtesy: iStock/doguhakan)

Enhanced geothermal systems (EGS) that retrieve heat from dry rock could add to the renewable energy mix but we don’t fully know the geological impact of pumping water deep underground. Given that the systems could lie close to large populations, it’s prudent to solicit expert opinion on the risk of inducing seismic activity. The range of responses from such a panel, however, can be surprisingly diverse.

Scientists in Switzerland and the US convened a panel of 14 international experts and presented them with a hypothetical EGS plant and its geological context. The experts provided their individual judgements in one-on-one interviews with a member of the research team.

Modelling the Mississippi

25 Sep 2018 James Dacey

Modelling the Mississippi

Physical river model helps science, policy and education

If a picture’s worth a thousand words, then the 1000 m2 physical model of the lower Mississippi river at LSU Center for River Studies must seem like a treasured tome to hydrologists. In this video, LSU researcher Clint Willson explains why the Mississippi model is such a useful tool for scientists, policy makers and the general public.

Located at the Baton Rouge Water Campus, it is one of the world’s largest movable bed physical models – 20 high-definition projectors illuminate the model and bring the river and coast to life. Being highly dynamic, the model is used to study the geography and hydrology of the Mississippi under different scenarios. That includes visualizing rising water levels during hurricanes, as well as longer-term impacts of sea-level rise on coastal lands.

‘Inside out’ nebula points to ‘born again’ star

11 Aug 2018

Born again: composite image of HuBi 1. (Courtesy: Martín Guerrero et al/Nature Astronomy)

Astronomers have shown that an “inside out” planetary nebula could have been created by a “born again” event in a star that was once similar to the Sun. The observation suggests that the Sun could also experience the same fate sometime in the distant future.

Low- to medium-mass stars can be born again during the final stages of their lifetimes. This occurs when ionized gas ejected from a star is attracted back onto its surface, creating a shock that briefly re-ignites thermonuclear fusion. As this process is so brief, however, few examples have been detected, so it is poorly understood.

When stars have exhausted their fuel, several things can happen. Those heavier than about 1.4 solar masses – the Chandrasekhar limit – will explode in a supernova. However, stars of less mass that can no longer produce radiation pressure to resist the force of gravity eschew such drama and simply collapse to form white dwarves. Before they do this, however, they shed their outer layers as ionized gas creating planetary nebulae.

Acoustic waves reveal that some stars spin faster at the equator than at the poles

25 Sep 2018

Spinning around: the green arrows represent rotation speed in the stellar convection zone. Differential rotation is inferred from the oscillatory motions of the star seen as orange/blue shades on the right side of the figure. (Courtesy: MPI for Solar System Research/MarkGarlick.com)

An international team of astronomers has observed latitude-varying rotation in the outer layers of 13 Sun-like stars and shown in great detail that the Sun is not alone in displaying this curious behaviour. Othman Benomar at New York University, Abu Dhabi and his colleagues made the discovery by measuring distinctive patterns of acoustic oscillations in the stars. Their discovery could help to advance our understanding of the elusive mechanisms which play out deep within the Sun and other stars.

Fade boosts lithium battery stability

25 Sep 2018 Anna Demming

Schematic diagram of Li deposition for Li foils coated with a GZCNT interfacial layer.

Lithium has been the material of choice for lithium battery anodes on account of the ultrahigh theoretical capacity of 3861 mAh g-1. However, despite successful use of lithium in primary batteries, in practice the performance of lithium falls far short of its theoretical potential. One of the main factors is the formation of dendritic structures on the lithium anode during the repeated plating or stripping processes, which inhibits its cyclability and leaves it prone to short-circuiting and hazardous thermal failure. As a collaboration in China show, one favourable way of manipulating the deposition of lithium during cycling to avoid dendrite formation is by constructing an interfacial layer that gradually fades from lithiophilic to lithiophobic properties.

Huge vegetation change could affect Earth

14 Sep 2018

Forests like this in Kahuzi-Biega national park, DRC, will be at risk. (Courtesy: By Forest Service, USDA, via Wikimedia Commons)

The planet’s greenery – prairie grasslands, riverine swamps, Sahel drylands, European woodlands, tropical rainforest and Alpine meadows – could be about to be overtaken by a huge vegetation change as the world warms at a dangerous rate.

The warning comes not from computer simulations of what could happen under the notorious “business-as-usual” scenario, in which humans go on burning ever greater quantities of fossil fuel, to raise the levels of greenhouse gases in the global atmosphere, but from a simple natural experiment while humans were still Neolithic nomads.

Between 21,000 and 14,000 years ago, near the end of the last Ice Age, the world warmed by between 4 °C and 7 °C. And the world’s plants preserved a register of the changes during that era.

Hygroscopic aerosols linked to forest decline

24 Sep 2018

(Courtesy: iStock/Trout55)

Hygroscopic aerosols — particles in the air that attract water — could be causing forest declinearound the world, according to experiments performed in Germany. Researchers believe that aerosol accumulation on trees enables thin bridges of liquid to form between the leaf interior and the leaf surface, causing the plants to dry out much more rapidly.

“In the atmosphere, aerosols act as cloud condensation nuclei,” says Juergen Burkhardt of the University of Bonn, Germany. “Deposited aerosols on leaf surfaces act almost the same way but attract water from inside the plant.”

Targeted infection control

27 Jun 2018

This article first appeared in the 2018 Physics World Focus on Biomedical Physics

Medical devices that incorporate hydrogels into silicone rubber could release antibiotics into areas where they are needed most. Erik Brok, Caroline Boudou, Martin Alm and Peter Thomsen describe how neutron scattering is helping researchers to understand and optimize the structure of these silicone-hydrogel networksReservoir for disease: Catheters can harbour harmful micro-organisms, such as the yeast Candida albicans, shown in this scanning-electron micrograph. (Image courtesy: Dennis Kunkel Microscopy/Science Photo Library)

Hospital-acquired infections (HAIs) are one of the biggest challenges in modern healthcare. Within this wider problem, urinary-tract infections associated with catheter use are a particular concern: in 2001 a US study found more than half a million cases each year, accounting for approximately 40% of all HAIs (Int. J. Antimicrob. Agents 17 299). Such infections often stem from biofilms that form when a catheter is inserted into a patient’s urethra. These biofilms – which are made up of micro-organisms and their extracellular detritus – act as refuges for bacteria, making infections persistent and difficult to treat. Developing novel catheter materials that resist biofilm attachment is thus a promising strategy for reducing the number of HAIs.

Europe emerges as neutron science powerhouse

20 Apr 2018 Michael Banks

Number one for neutrons: During 2005–2015 the Institute Laue-Langevin in Grenoble published more papers than any other neutron facility in the world. (Courtesy: ILL/Max Alexander)

Europe’s neutron facilities are leading the world in terms of the number and quality of publications – but their pre-eminence could be threatened in the coming decade as new facilities in Asia ramp up. That is the conclusion of a new analysis carried out by researchers at Forschungzentrum Jülich (FZJ) in Germany and published on arXiv.

They found that in the 10-year period from 2005 to 2015, some 42,689 papers were published by researchers based on experiments carried out at neutron labs worldwide, with Europe accounting for more than half (52%) of all papers in the field. Labs in Asia/Oceania were second with 16,220 (20% of the total), followed by North America at 15,347 papers (19%). Within Europe, the strongest countries were France with 8091 neutron-science publications followed by Germany (8041) and the UK (5510).

Beefing up X-rays at the European Synchrotron Radiation Facility

17 Aug 2018

This article first appeared in the 2018 Physics World Focus on Instruments and Vacuum under the headline "Beefing up X-rays"

A major upgrade to make the ESRF light source even brighter will rest on four pillars of instrumentation, as Jon Cartwright reports

(Courtesy: top left: ESRF; top right: ESRF; bottom left: ESRF; bottom right: BEST-BACKGROUNDS/Shutterstock.com)

Synchrotrons push the boundaries of science at every frontier. On the one hand, synchrotrons such as the Large Hadron Collider at CERN in Geneva – accelerators designed to smash particles together at high energies – test the very foundations on which physics is based. On the other hand, synchrotrons can also be used to explore the less grandiose, but just as important “science of the everyday”. No particle-smashing takes place at synchrotron facilities; instead the goal is to harness the light – typically X-rays – generated when charged particles are accelerated continuously in a ring. These X-rays can be focused on pretty much any material – biological tissue, protein crystals, cosmetics, engineering alloys, superconductors and dinosaur fossils to name just a few – in order to determine how they behave, and understand why.

Initiated back in 1988, the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, was the first “third generation” synchrotron.

3D virtual heart helps pinpoint irregular heartbeat

24 Sep 2018

© AuntMinnie.com

Researchers from Johns Hopkins University used a proprietary 3D virtual heart simulator to preoperatively identify areas of cardiac tissue that required surgical treatment for an irregular heartbeat, according to an article recently published in Nature Biomedical Engineering. The method may improve cardiac ablation procedures.

The group, led by senior author Natalia Trayanova of Johns Hopkins, developed the “virtual heart” model using a combination of cardiac imaging and computational modelling.

Precise proton range detector gets ready for the clinic

24 Sep 2018

Illustration showing the gantry, proton treatment head, patient, top X-ray flat panel and prototype range verification system.

Proton pencil-beam therapy reduces damage to surrounding tissue compared with conventional radiotherapy, because protons stop at a certain distance within the tissue, whereas photon beams continue through the patient. Therefore, proton beams are used to treat tumours in critical organs of the body, such as the brain.

Particle accelerators deliver a dose of protons at energies sufficient to reach the entire tumour. However, accuracy in proton delivery is limited by uncertainty surrounding the proton beam range.

“Currently we have to irradiate an area with a margin of error around the tumour, to make sure that we actually get the whole tumour,” explains Joost Verburg from Harvard Medical School. “If you are able to precisely measure [protons], you could create a dose distribution that is more focused on the tumour and avoids nearby organs.”

Ferrimagnets speed up racetrack memories

24 Sep 2018 Belle Dumé

Meandering domain walls and skyrmions in ferrimagnetic thin film

Spintronics devices, which exploit the spin of an electron as well as its charge, could be ideal for use in high-density data storage devices and for next generation information processing. One promising technology involves using magnetic solitons, such as nanoscale domain walls and magnetic skyrmions, which can function as mobile bits, to encode information, and then moving these bits using a current in devices known as racetracks. The main challenges here are to make smaller bits and then efficiently move these at high speeds. Until now, researchers mainly focused on ferromagnetic materials to make such bits, but these unfortunately have their limitations for when it comes to how small they can be made and the speed at which they can be moved. Material scientists and physicists in the US and Germany say they have now found a way to overcome this problem by using ferrimagnets instead. This new class of materials allow for order-of-magnitude improvements in speed and size and means that the technology might now be brought to market in a reasonably short timeframe.

Ghost images obtained using relativistic electrons

22 Sep 2018

Ghostly apparition: schematic of the ghost imaging system, which uses a laser beam (violet) and a beam of relativistic electrons (gold). (Courtesy: G Stewart/SLAC National Accelerator Laboratory/Phys. Rev. Lett.)

Relativistic electrons have been used to carry out “ghost imaging” of a sample for the first time. The research was done by Siqi Li at SLAC National Accelerator Laboratory and colleagues, who used a clever way of getting around the problem of producing two correlated electron beams. The technique could be used to improve analysis techniques that use beams of electrons to probe the properties of materials.

Optical ghost imaging is a useful tool that can spatially resolve the characteristics of a sample using just a single-pixel detector – rather than the multipixel arrays found in digital cameras. The technique involves splitting a beam of light into a pair of correlated beams called the signal and reference beams. The signal beam strikes the sample before hitting the single-pixel detector.

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Energy storage technologies vie for investment

22 Sep 2018 Anna Demming

One of the conveniences that makes fossil fuels hard to phase out is the relative ease of storing them, something that many of the talks at Advanced Energy Materials 2018 aimed to tackle as they laid out some of the advances in alternatives for energy storage.Max Lu during the inaugural address at AEM 2018

“Energy is the biggest business in the world,” Max Lu, president and vice-chancellor of the University of Surrey, told attendees of Advanced Energy Materials 2018 at Surrey University earlier this month. But as Lu, who has held numerous positions on senior academic boards and government councils, pointed out, the shear scale of the business means it takes time for one technology to replace another. “Even if solar power were now cheaper than fossil fuel, it would be another 30 years before it replaced fossil fuel,” said Lu. And for any alternative technology to replace fossil fuels, some means of storing it is crucial.

Batteries beyond lithium ion cells

Lithium ion batteries have become ubiquitous for powering small portable devices, but as Daniel ShuPing Lau, professor and head at Hong Kong Polytechnic University, and director of the University Research Facility in Materials pointed out, lithium is rare and high-cost, prompting the search for alternatives. He described work on sodium ion batteries, where one of the key challenges has been the MnO2 electrode commonly used, which is prone to acid attack and disproportionation redox reactions. Lau described work by his group and colleagues to get around the electrode stability issues using environmentally friendly K-birnessite MnO2 (K0.3MnO2) nanosheets, which they can inkjet print on paper as well as steel. Their sodium ion batteries challenge the state of the art for energy storage devices with a working voltage of 2.5 V, maximum energy and power densities of 587 W h kgcathode−1 and 75 kW kgcathode−1, respectively, and a 99.5% capacity retention for 500 cycles at 1 A g−1.

Thermal ablation effectively treats early-stage lung cancer

19 Sep 2018 Tami Freeman

Comparable outcomes: overall survival for patients who underwent thermal ablation or stereotactic radiotherapy as primary treatment for stage 1 NSCLC. (Courtesy: RSNA)

Thermal ablation is a safe, effective treatment for early-stage lung cancer, according to a study from Yale School of Medicine. The results show that ablation may provide an alternative approach for patients who are ineligible for lung cancer surgery (Radiology10.1148/radiol.2018180979).

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases. For early-stage disease, surgery is the treatment of choice. But older patients and those with comorbidities may not be suitable for surgery due to a higher risk of complications. Stereotactic radiotherapy (SRT) is a viable alternative for such patients and can provide high local control rates. Irradiation, however, sometimes harms healthy tissue surrounding the tumour and carries a risk of short-term and long-term toxicities.

Action to tackle climate change splits US voters along party lines

02 Aug 2018

Reaching a consensus: a large section of both US Republicans and Democrats agree that climate change is not only happening but is also caused by human activity. (Courtesy: iStock/clintspencer)

A large section of both US Republicans and Democrats agree that climate change is not only happening but is also caused by human activity. That is according to surveys of more than 2000 members of the American public as well as interviews with two former members of Congress (Perspectives in Psychological Science 13 492). The researchers discovered, however, that while members of both parties agree that tackling carbon-dioxide emissions would reduce climate change they disagree over how to do it — with individuals mostly supporting policies proposed by their own party.

Americans are different from many other countries, not only in the polarization of their beliefs within the major political parties but in the extent to which these beliefs are associated with environmental support for environmental actionLeaf Van Boven

Carried out by David Sherman, a psychologist at the University of California, Santa Barbara (UCSB), together with Leaf Van Boven from the University of Colorado and UCSB graduate student Phillip Ehret, the study found that people’s stances toward climate policy are strongly shaped by political partisanship, not simply by their belief in climate change.

Forests cut warming better than technology

21 Sep 2018

Left intact, forests like this in Africa are best for saving the climate. (Courtesy: By Forest Service, USDA, via Wikimedia Commons)

Simple solutions are often the best, and British and European climate scientists have identified one: forests cut warming better than the technological solutions now being widely canvassed.

They have established some simple ground rules for limiting global warming to the international target of an average rise of no more than 1.5 °C by 2100.

Rule one: do not try to generate electric power with biofuels made from harvested crops, trees or grasses, and do not spend even more money trying to capture the carbon dioxide emissions, liquefy them and bury them deep underground. To do so successfully would require at least 380 million and maybe up to 700 million hectares of farmland.