Illustration of pulsed radiofrequency applied to nerve root. (Courtesy: Radiological Society of North America)
Researchers from Sapienza University of Rome have demonstrated that CT-guided pulsed radiofrequency (pRF) provides a safe and effective treatment for acute lower back pain that doesn’t respond to conservative therapy. The minimally invasive procedure involves applying pulses of energy directly to the portion of the nerve responsible for sending pain signals.
“Pulsed radiofrequency creates a nerve modulation, significantly reducing inflammation and its associated symptoms,” said senior author Alessandro Napoli, who presented the study today at the RSNA annual meeting.
Lumbar disk herniation is a common, often debilitating, condition that affects the disks between the vertebrae of the lower spine. Herniation occurs where the gel-like material in the centre of the disk bulges through a tear in the disk’s exterior and puts pressure on the roots of the nerves. Conservative treatment options range from over-the-counter pain medications to injections of corticosteroids into the affected area of the spine. Non-responders may require surgery and, in some cases, the entire disk must be removed and the vertebra fused together for stability.
Napoli and colleagues studied the use of pRF in patients with back pain from lumbar disk herniation that had not responded to prolonged treatment. In 128 patients, they delivered pRF under CT guidance directly to the root of the symptomatic nerve, for 10 minutes. For comparison, 120 patients received one to three sessions of CT-guided steroid injection on the same anatomical target with no pRF.
The one-year outcomes demonstrated that CT-guided pRF was superior to the injection-only strategy. Patients who received pRF saw greater overall improvement in pain and disability scores during the first year. Relief of leg pain was faster in patients assigned to pRF, and they also reported a faster rate of perceived recovery. The probability of perceived recovery after one year of follow-up was 95% in the pRF group, compared with 61% in the injection only group. Six patients were considered partial responders and required a second PRF session.
Image of herniated disc before treatment and at one-month follow-up. (Courtesy: Radiological Society of North America)
“Given our study results, we offer pulsed radiofrequency to patients with herniated disk and sciatic nerve compression whose symptoms do not benefit from conservative therapy,” says Napoli. “Of the different therapies available, pulsed radiofrequency is among the least invasive. Treatment lasts 10 minutes, and one session was enough in a large number of treated patients.”
The use of pRF may help many patients with sciatic disk compression avoid surgery. It could improve outcomes for patients set to receive corticosteroid injections. “We learned that when pulsed radiofrequency is followed by steroid injection, the result is longer lasting and more efficacious than injection only,” Napoli explains. “The effect of pulsed radiofrequency is fast and without adverse events.”
The concentration of airborne particulate matter (PM2.5) and sulphur dioxide (SO2) decreased from 2015 to 2017 at more than half of China’s 1000 air quality monitoring stations. But amounts of ground level ozone increased at half the sites over the same period, according to new analysis.
The lowest PM2.5 concentrations — 20-25 µg m-3 — were in Hong Kong, Taiwan and Tibet. While the downward trend is encouraging, these figures are still above World Health Organization guidelines. Reductions in the concentration of sulphur dioxide were also widespread, with 59% of monitoring stations in the study reporting a significant reduction. On average, levels decreased by 3.4 µg m-3 per year.
Falling levels of PM2.5 are in line with satellite studies but the latest analysis, which includes data from more than 1000 sites, provided surprises too.
“Satellite observations show a decreasing trend in NO2 concentrations across China, but we find that large decreases in NO2 in some regions of the country are being offset by increases in other regions,” says Ben Silver of the University of Leeds, UK.
Rising NO2 concentrations could help explain why ozone values have increased, although Silver points out that in heavily polluted cities decreasing NO2 emissions can also push up ozone levels. Ozone forms from complex reactions in the atmosphere involving NO2 and volatile organic compounds; at ground level it can be detrimental to health as well as crop yields.
The researchers are also investigating the impact of the weather. “Day-to-day variation in air quality is most strongly affected by weather conditions rather than emissions – so a year which had a higher than average occurrence of weather conditions conducive to poor air quality, followed by a year which had favourable weather conditions could make it look like air quality has improved, while emissions have stayed constant,” says Silver.
Next the researchers will use an air quality computer model to probe the 2015 – 2017 measurements in detail. They hope to establish whether decreases in PM2.5 and SO2 can be ascribed to emission controls, meteorology or a combination of both.
Picturing a scene of rapid industrialization and urbanization brings home the challenge of improving air quality. But access to ground-level data provides a tool for tracking progress and identifying future opportunities.
“Much of China’s air quality control has focused on the ‘low hanging fruit’ of large sources of air pollution, namely their coal fired power stations,” says Silver. “Our research shows that a large fraction — around one third — of PM2.5 pollution can be attributed to heating and cooking emissions from households.”
“There are three things that make me incredibly proud that Europe hosts the ESRF,” says Carlos Moedas, the European commissioner for research, science and innovation. “First, the ESRF is a beacon of excellent science. Second, it is a powerhouse of international scientific collaboration. And third, it has created an interdisciplinary hub where scientists of all disciplines come together to exchange their knowledge.”
Moedas’s words sum up what most people feel about the ESRF, which for 30 years has brought scientists together to push the frontiers of X-ray science. It was in 1988 that the research ministers of 11 European countries signed the Convention and Statutes of the ESRF, bringing the facility formally into existence. Just four years later it was up and running – on time and on budget – generating X-rays of energy and quality that exceeded even the designers’ expectations.
It was the world’s first “third-generation” synchrotron light source, surpassing the capabilities of earlier second-generation sources through its use in the storage ring of devices known as undulators and wigglers. These intensified the production of X-rays, providing users with the most powerful microscope ever to understand the microscopic nature of matter.
You can find out more about the ESRF and its three-decade journey at the forefront of X-ray science in a special anniversary issue of ESRFnews, a magazine that is produced through a long-standing partnership between the ESRF and IOP Publishing, which also publishes Physics World. This special issue, with a digital edition that is freely available to read online, features a special fold-out timeline with recollections from people who witnessed the key events, and examines how the ESRF has helped to revolutionize 10 areas of science, from the basic building blocks of life to some of humanity’s most important industrial processes.
Completing the picture is a look into to the future, with the upgrade to the Extremely Brilliant Source (EBS) set to turn the ESRF into the world’s first high-energy fourth-generation synchrotron source. “The ESRF is, and will be, the leader in synchrotron science, thanks to its governance and its ability to attract the best minds worldwide,” says Francesco Sette, the ESRF’s director-general. “As long as X-rays are needed, the ESRF will be there to supply the best service.”
Picture this. Injured from an accident, you require brain surgery. During surgery, your doctors insert dime-sized, paper-thin devices into your brain. The devices unfurl and, almost immediately, start to collect data on your brain’s health. After surgery, they are still hard at work, keeping you safe. When the devices are no longer needed, they dissolve, leaving no trace of their presence.
A collaboration between engineers and neurosurgeons in the US, China and Korea has recently developed and characterized such a device (Adv. Mat. 10.1002/adma.201801584).
The device, called a bioresorbable brain implant, will allow doctors to monitor a patient’s vital signs and glucose and oxygen levels following surgery. After it is no longer needed, the implant will dissolve away. Unlike the permanent devices used today, surgery is not required to remove bioresorbable implants. The bioresorbable implants will also improve patient comfort and reduce complications, a desirable feature for individuals who have had life-endangering brain surgery for traumatic brain injuries or other conditions.
Form and function
The efforts of Weidong Zhou from the University of Texas at Arlington and the interdisciplinary research team required them to apply a decade’s worth of research to clinical principles in order to create the implant.
“We began exploring how to integrate optical waveguides and nanophotonic cavities for bio-implantable optical probes to make them more comfortable and introduce the ability to have the body absorb the devices completely,” says Zhou.
The bioresorbable brain implants rely on waveguides: physical structures used to guide light that are typically found in integrated optical circuits or optical communication systems. The waveguides collect precise, continuous and reliable spectroscopic data on brain health by accurately delivering and sensing light at targeted sites — sometimes as small as a single cell — in the brain.
The implants are made from biocompatible wafers of monocrystalline silicon (m-Si) filaments and a poly(lactide-co-glycolide), or PLGA, substrate. The researchers chose m-Si because it can be formed into effective, nanoscale geometries for optical sensing applications. The PLGA encapsulates the m-Si wafers and allows the researchers to tweak the amount of time it takes the implant to degrade.
Currently, the implants use near-infrared (NIR) transmission spectroscopy to measure blood oxygenation to within 4% and glucose to within 15 mg/dl. These spectroscopic measurements are vital for preventing metabolic disorders and other medical conditions in patients.
Look to the future
The future of silicon-based photonics in bioresorbable technologies and other transient implants is vast.
The neurosurgical community would also like to be able to monitor brain function, says John Rogers from Northwestern University, the lead author of the study. This will be accomplished by monitoring neurotransmitters, the body’s chemical messengers. Neurotransmitters send messages between neurons, or from neurons to muscles, to affect behaviour and control the activity of various organs, which directly impacts blood pressure, heart rate and other functions.
The researchers also hope to make the bioresorbable brain implants even smaller to minimize invasiveness and reduce the risk of damage to brain tissue. Testing advanced versions of the implant in animals will allow them to make final refinements to the devices before commercialization.
Zhou recently received a National Science Foundation Partnerships for Innovation grant to help bring the implant to market. The researchers estimate that the bioresorbable brain implant will cost around $6 per foot to produce.
This brain implant is only one biodegradable device on the horizon. Rogers’ lab has developed a number of biodegradable devices to address unmet medical needs, from diagnosis to therapy and monitoring.
“We have […] published several examples of full systems with clinically relevant modes of operation,” says Rogers. “We have demonstrated various devices in animal models and we have plans for human trials — but none of these devices is yet commercialized.”
Accidental entrepreneur: Volker Türck’s foray into scientific consultancy began when he was made redundant. (Courtesy: Irina Ostapenko)
In 2005 I founded my own company, Türck Engineering – a scientific consultancy service. This step was not the result of long-term strategic planning, and I’d never had any strong desire to be self-employed. On the contrary, it was a decision I made in the moment, thanks to the circumstances at that time – and it was likely the best career decision I have ever made.
Today, I am the managing director of the company, which includes five other employees, and we specialize in two areas: optical design and data science. The optical systems we design and develop are used in optical sensors for industrial applications, measurement devices for medical applications, fibre optics for telecommunications, and even light-shaping optics for applications such as railway signalling. A few years ago we began getting involved in data science, when customers who ordered the design of an optical-measurement system came back and asked what they could learn from their measurement data. We also develop strategies and algorithms to analyse data obtained from all types of measurement processes, so that our clients can turn their data into knowledge.
Our customer base is widespread, ranging from medical device development to automotive production, and material and fault analysis. Over the past 13 years, the company has tackled over 100 projects, for more than 50 customers, from 10 countries all over the globe. Our customers range from small start-up companies to big multi-nationals.
But becoming an entrepreneur was never my plan. In 2001, after completing my PhD in semiconductor physics at Technische Universität Berlin, I took on a two-year post-doc at the European Laboratory for Nonlinear Spectroscopy (LENS) at the University of Florence in Italy. There I developed and built a novel confocal laser scanning microscope to manipulate photonic crystals in a controlled fashion. My postdoc was a transition for me, as I went from being a user of optical systems to becoming their designer and developer.
In academia, money is often a problem, but time is abundant. In industry it is quite the opposite
After these two very fulfilling years in academic research, I decided to take a step in a different direction and took up a position as development engineer at Infineon fibre optics in Berlin. This was a very different world from the academic environment that I was used to – in academia, money is often a problem, but time is abundant. In industry it is quite the opposite, as results must be achieved within a limited amount of time. While the latter may appear stressful, I found the work very fulfilling as the projects were smaller, better defined, and, most importantly, people cared about the results.
I would have happily remained at Infineon, but the company decided to sell its fibre-optics business and to lay off all staff in 2004. For me it was the swift end of a job that I had started only 18 months before. During the shut-down phase, every Infineon employee was offered outplacement coaching, and the person who coached me was convinced that being self-employed was brilliant. At the time, I had the vague idea of setting up a scientific consulting service, where companies would outsource their problem-solving needs.
At my coach’s encouragement, I wrote an actual business plan that I could use to apply for state funding for the initial phase of business. At that time, the federal government in Germany provided very generous grants for start-ups. Together with compensation from my former employer, I had enough funds to cover me for a year, even if I never found a single customer, and so decided to go for it and set up my own business. My first actual client was a former colleague from university, who had started his own company about six years before me. He needed someone to carry out optical simulations to optimize laser-fibre coupling for high-power laser diodes.
For the first few years, I was a solo entrepreneur – if something needed doing, I had to do it. I had to learn about things such as finance, bookkeeping, taxes, marketing and communications. Some of this was not as straightforward as you would imagine – as a scientist I was used to communicating my results, but this was usually to people with the same background. In industry, you have to convey your message to people from different backgrounds, who may have no technical expertise, and who may have very different priorities, so you must see their point of view.
For a long time, my marketing and promotion “strategy” was to wait for the phone to ring
Other areas, such as marketing or promotion, were downright awkward. In a one-man enterprise you must shamelessly promote yourself, which can feel very strange. I must admit that, for a long time, my marketing and promotion “strategy” was to wait for the phone to ring. Fortunately, I had a wide and growing network of friends and ex-colleagues, many of whom were my initial clients. Luck also had a role to play: a nerdy chat with somebody at lunch or dinner, and suddenly a new customer was won.
Going for growth
After eight years as a one-man band, I finally reached the point where I needed to bring others on board. Once more, luck and coincidence played a part, as all of my current coworkers came from my network of friends and ex-colleagues. Today we stand as a team of five experts, working in very diverse areas. The common thing that unites all our projects is that we apply the methods of scientific problem-solving, no matter what we are working on. We are problem-solvers, and our skills are those we learned as physicists: a systematic approach, dividing big problems into smaller ones, and solving them one by one. The tools we use are statistics, programming and model-based thinking, all of which a physicist is very well-trained in.
My company’s successes over the past 13 years have been thanks to a good mix of curiosity, coincidence, luck and flexibility. Obviously, without Infineon shutting down its plant, I would not have started my company. But I made the best out of this negative event and created something positive for myself. In one case, a participant in a software training session that I was delivering turned up a day early because of a mix-up of dates. We went for lunch and had a chat – today his company is one of our most important clients. You cannot plan for such events, and I am not a proponent of large, long-term forecasting. Of course, some planning is needed, but grab opportunities when you can, and trust your instincts.
People often think they need a “big idea” to set up a business, in the hope of becoming the next Google, or to come up with something “disruptive”, but it doesn’t have to be like that. It is absolutely fine if you can do something a little bit better or differently from others in the market. The idea of an engineering consultancy was not novel or trailblazing, but our tailored approach was enough to make us stand out.
If I were to summarize my experience and give some tips, it would be the following: take the time to learn how industry works. Thanks to my time at Infineon, I learnt how a company is organized, and what it may need – I could not have done this straight out of academia. Many of the problems that a company faces may appear trivial to the scientist, but they are real problems and they need swift resolutions.
Create and maintain a network – not just one that only exists within the confines of LinkedIn or Xing. To do business, you need to meet and to talk to people in real life. Such encounters form much better bonds and are therefore much more valuable.
Clarity is key
Do not spend too much time planning ahead – though of course you must clearly know the direction you want to take, as well as have a clear idea of your economic situation. Crucially, you should know when to stop. For instance, my red line is that I do not want to run into any financial debt.
Finally, you need focus and dedication. If you decide to become your own boss, be sure to know that it will not be a nine-to-five job, and you will have sleepless nights worrying about how to find the next customer. You will undoubtedly make mistakes, but keep on going. I believe that, in the end, it is worth it.
The first probe to study the deep interior of Mars has successfully landed on the red planet. After spending over six months travelling around 550 million kilometres to Mars, NASA’s $800m Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission made a soft landing on the red planet in a flat region of the planet called Elysium Planitia. It will now spend the next couple of months deploying the craft’s instruments before studying Mars for at least two years.
We finally will explore inside Mars and deepen our understanding of our terrestrial neighbour
Lori Glaze
InSight took off on 5 May from Vandenberg Air force Base in California aboard an Atlas V rocket. The mission’s main aim is to study the planet’s interior by measuring its heat output and listening for seismic events on the planet. “Now we finally will explore inside Mars and deepen our understanding of our terrestrial neighbour as NASA prepares to send human explorers deeper into the solar system,” says Lori Glaze, acting director of NASA’s planetary science division.
InSight carries two cameras as well as three other instruments, all of which will be deployed by the craft’s robotic arm. These include a geodetic instrument built by NASA’s Jet Propulsion Laboratory (JPL) to determine the planet’s rotation axis as well as a device that can measure seismic waves travelling through the planet, made by a consortium led by France’s Paris-based National Centre for Space Studies. The third instrument, built by the German Aerospace Center in Cologne, will measure the flow of heat from the interior of the planet by burrowing a probe 5 m into the surface.
Launched alongside InSight were two CubeSats, dubbed Mars Cube One (MarCO). They will test relaying communication signals from InSight to Earth and is the first time that such small satellites have been sent to another planet. “Just by surviving the trip so far, the two MarCO satellites have made a giant leap for CubeSats,” says Anne Marinan, a MarCO systems engineer based at JPL.
Claimed to be the first-ever “magnetic field diode”, a device in which one wire coil can transfer its magnetic field to a second coil, but not the other way around has been created by Jordi Prat-Camps and colleagues at the University of Innsbruck in Austria. The team believes that further improvements to the diode could allow it to be used in a wide range of applications in electrical devices.
Electrical diodes, which allow currents to flow in one direction but not the other, are a fundamental component of electronics. Engineers have long sought a comparable device that would direct magnetic fields in only one direction – something that would be incredibly useful in many technologies. Until now, however, the Lorentz reciprocity principle has been a formidable barrier to creating a practical magnetic field diode.
The principle states that when a magnetic field source, such as a conducting wire coil, induces a field in a second source, the second will be able to induce a field in the first. Therefore, a magnetic field diode in which the field can only be transferred coil-to-coil in one direction should not be possible.
One-way system: illustration of the diode coils set within the U-shaped groove in the wall of the rotating cylinder. The cylinder is rotating to the right, which prevents the magnetic field from being transmitted to the left. (Courtesy: Luis Veloso)
U-shaped cross-section
Through theoretical calculations, Prat-Camps and colleagues identified a special situation where the symmetry dictated by the reciprocity principle can be broken. They found that this could be achieved if the two coils were placed within the walls of a hollow, conducting cylinder rotating at a constant velocity. The team then built a cylinder with walls that have a U-shaped groove containing the coils (see figure) and demonstrated its practicality in the lab.
“Our device makes possible to transfer the magnetic field from a first magnetic element. When roles are inverted, and one tries to send magnetic field from the second to the first, no magnetic field is transferred,” says Prat-Camps, who is now at the University of Sussex in the UK. “When the conductor is properly placed near to the magnetic elements and is moved at the right speed, the coupling between them becomes unidirectional, and a diode for magnetic fields is realized.”
If a commercially-viable magnetic field diode can be made, it could transform the capabilities of electrical components. It could, for example, enable wireless charging where energy only flows in one direction. It could also be used to improve devices that currently use symmetrically-coupled magnetic elements, including electric motors, transformers and MRI machines. While the device created by the team is currently bulky and not yet practical for use in everyday electrical components, the researchers believe it could be greatly improved with further research.
Perforated graphene membranes could be used in next-generation filtration and gas separation applications because they can efficiently and quickly filter liquids and gases. A team of researchers in Switzerland and Korea has now developed two new processes to make such membranes with sub-100 nm pores. The structures are not only simpler and more permeable than those developed previously but they can also be scaled for industry – something that has been a challenge so far. The membranes might be used to remove bacteria and viruses from drinking water, in biomedical filtration applications, wearable electronics platforms and breathable fabric.
Graphene is a sheet of carbon just one atom thick, first isolated in 2004. Ever since then, researchers have been looking to use the material as a filter by perforating it with nanometre size holes.
Two bottom-up and top-down techniques are complementary
The highly porous perforated graphene produced by Hyung Gyu Park and colleagues of ETH Zurich and Pohang University of Science and Technology (POSTECH) could be suitable for ultrafiltration and as a 2D scaffold for making ultrathin gas-selective polymers. The two bottom-up and top-down techniques developed by the researchers are complementary and allow them to make perforated membranes comprising a predefined number of graphene layers.
“Our top-down method combines block-copolymer nanolithography and anisotropic plasma etching of double-layer graphene and allows for scaled-up perforation in a relatively cost-effective way,” explains Park. We have spent many years trying to obtain a large-scale uniform pore pattern using self-assembled block-copolymers made from polystyrene (PS) and polymethylmethacrylate (PMMA) by allowing few-tens-of-nanometre-wide PMMA spheres to form within a PS matrix. After chemically stripping the PMMA spheres away, we obtain a large-scale uniform pore pattern in the PS matrix.”
Fast and cost-effective manufacturing method
The researchers say that they can puncture the entire graphene sheet with nanometre-sized holes by bombarding ion plasma through the porous PS-matrix. “The spherical block-copolymers allow for large-scale patterning while the single-step plasma etching of the pores makes this manufacturing method fast and cost-effective,” explains team member Roman Wyss.
The bottom-up method is different in that it creates pores in graphene when it is actually being synthesized. “Here, we allow catalytically inactive nanoparticles to spread over a copper catalyst layer before the chemical vapour deposition step in which graphene is manufactured,” adds team member Kyoungjun Choi. “By controlling the size of the inactive nanoparticles, we can easily obtain porous graphene.”
The two techniques, which are described in Science Advances DOI: 10.1126/sciadv.aau0476, produce samples up to 25 cm2 in size in which the pore size is uniform and controllable in the sub-20 nm to 50 nm range on average. The researchers tested their membranes by measuring the flow of nitrogen gas and liquid water through them.
Ultrafiltration membranes
“The structures we analysed have high permeances for liquids of up to 5.55 x 10-8 m3/s/Pa combined with good filtration/separation performance,” Park tells Physics World. “They might be used as ultrafiltration membranes able to remove, for example, bacteria and viruses from drinking water.”
Biomedical filtration, wearable electronics platforms and breathable fabrics may also be potential application areas. Indeed, the researchers, who are funded by the Swiss government, say they are now working with a Swiss start-up company, HeiQ Materials AG to develop a breathable textile that repels liquids while being permeable to gases.
“We are now exploring these various filtration applications and are also working on better understanding the mechanisms behind liquid and gas transport in these membranes,” says Park.
Since its opening in 2007, the Diamond Light Source has supported research from partner users in fields including art conservation, nanotechnology, and biology. This year, however, its work took an introspective turn with the synchrotron’s first-ever school specifically for engineers.
The Early Career Engineering School, held from November 12 through November 16, 2018, provided engineers with the knowledge necessary to understand the design of x-ray beamlines. Diamond accepted fifty engineers, eleven of them women, to attend. The group represented countries including the United States, China, India, and Switzerland.
Engineering specialists
“Basic as well as innovative, engineering is vital to the successful science carried out in synchrotrons,” says Sarah Macdonnell, Joint Head of Beamline Engineering at Diamond. “However, [engineering positions at synchrotrons] often require very different approaches to any previous engineering roles.”
The five-day course therefore began with conceptual introductions to synchrotron radiation, optics, and the skeleton of an x-ray beamline. Instructors could outline the parameters that determine specific system requirements with the 31 unique beamlines Diamond Light Source offers as examples.
“Our goal [was] to give these engineers a really good insight and grounding into many of the specialist technical issues that arise when designing, building and testing systems for light source facilities,” says Macdonell.
Hands-on designer light training
The engineers then used their working knowledge of synchrotron science to understand the design and manufacture of synchrotron components. Instructors highlighted the challenges they faced by addressing issues like thermal and mechanical stability, feedback systems, and different experimental techniques. Manufacturers that provide beamline parts such as FMB Oxford and Kurt J. Lesker also attended for the supplier’s exhibit. Overall, the course aimed to give practical advice from beamline scientists to aid in proper design of beamlines.
“Delegates [learned] what really matters in engineering design in light sources,” says Stewart Scott, Joint Head of Beamline Engineering at Diamond. “They [saw] real examples and [talked] to other engineers about the challenges they face here at Diamond.”
In this short video for our 100 Second Science series, Steven Jackson explain the principles behind magnetic resonance imaging (MRI). Jackson, a trainee clinical scientist at the Christie Hospital in Manchester, explains how intense magnetic fields and radio-frequency waves can be used to produce images of soft tissue inside the human body. One of MRI’s primary uses is the diagnosis of cancer as well as tracking how tumours respond to treatment.
