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Home » Page 863

Talking tech transfer at TRIUMF

What is TRIUMF Innovations?

We are the private sector-facing part of TRIUMF. If you are a company or a private investor wanting to interact with TRIUMF in any way, we are here to help facilitate that. Originally, our focus was very much on creating spin-off companies, but we also offer proton and neutron irradiation services, and we have a longstanding relationship with Nordion to produce medical radioisotopes for distribution across North America and the world.

What is your background?

I’ve been at TRIUMF for a little over a year, starting in February 2017. Before that I was in the biotech world – I worked for an organization called the Centre for Drug Research and Development as part of the founding executive team, and previously for a public biotech company. For me, the big overlap has been in nuclear medicine, because historically, a lot of the commercialization that TRIUMF does has been in that area. So there are definitely some things we’re working on where we’ll be able to leverage my experience and networks in biotech, but I’ve also learned a lot about physics in the past year.

How does TRIUMF Innovations help spin-offs get started?

It depends on the technology and who’s involved, but we might look for champions for a technology to develop it further; help companies create business plans; or try to find partners to license or invest in new technologies. A good example is ARTMS Products, which makes a cyclotron-based system for producing technetium-99m, a short-lived isotope used in medical imaging. Many hospitals have a small cyclotron in their basement where they produce isotopes for patient treatments, and the ARTMS product can either be added to this or the original equipment manufacturer can incorporate it into their system.

This technology was developed at TRIUMF in partnership with a consortium of Canadian research organizations to solve the problems associated with Canada shutting down the Chalk River nuclear reactor, which had previously produced essentially all of this important isotope. We helped ARTMS develop its business plan and find investors, and in 2017 it won the British Columbia Tech Association’s impact award for the most promising pre-commercial technology. It also closed its first round of venture financing just before Christmas that year, so we’re excited to see ARTMS evolve into a real operating business. It’s still a relatively early-stage company, but it has multiple successful installations with GE and the venture financing should enable it to ramp up.

What, in your view, are the biggest challenges facing start-ups in the instrumentation and vacuum sector?

Funding is a challenge for any start-up, but spin-outs based on laboratory research or equipment encounter an additional hurdle, which is that the funding available is generally intended for innovative new research. You don’t necessarily get funding to validate results, or to repeat an experiment to make sure you’ve got it right. So development funding is always a challenge. The other challenge is gathering the expertise you need from different areas and translating it out of a research setting and into a business setting. Suppose you have a bunch of scientists with a great idea. How do you present that idea as an investment opportunity? To do that, you need a new set of skills, a new language and new networks, and that’s a gap that we’re trying to fill.

Detector development: The DESCANT detector at TRIUMF. (Courtesy: TRIUMF)

We are working on a programme in partnership with the University of British Columbia’s Sauder School of Business that is designed not just for people who are going to found companies (although they are incredibly important and I look for them every day), but also for scientists who want to innovate and get their ideas out into the world while remaining involved in basic, discovery-driven research. We want to broaden the culture of entrepreneurship within TRIUMF so that even career scientists are informed about concepts such as confidentiality and intellectual property. The goal is to get these “intrapreneurs” more involved in creating technologies quickly, efficiently and cost-effectively so that these technologies are attractive for private-sector investment, while also educating people who are interested in working for spin-off companies about how that is different from working in a government laboratory or in academia.

Aside from ARTMS, what are some other projects that TRIUMF Innovations is working on right now?

A few years ago, a mining researcher at the University of British Columbia asked us if we could help her reconfigure a medical PET scanner so that she could use it to examine mining slurry. Our response was essentially, yes, we could, but we could also create a PET scanner that was specifically designed for mining applications – on the right size and scale, for example, and with detectors designed not for human disease but for industrial samples. And the professor was like, “Oh, yeah, that would be great!” However, there are other applications for this technology, too. It’s all about trying to understand what is flowing within a liquid sample, so you could also imagine using it with pulp in a paper mill or even in food manufacturing. The challenge is to figure out where the market need is and then develop the technology to meet that need.

Another company I’ll mention is CRM GeoTomography. It was initially funded via a grant from Canada’s Centres of Excellence for Commercialization and Research, which were set up to encourage commercialization and spin-off creation. That grant enabled CRM GeoTomography to develop a prototype detector that uses muons – which of course we study all the time at TRIUMF – to create a 3D map of the Earth’s crust, down to about a kilometre or so. A mining company might use that kind of map to understand where an ore deposit was, but we’re also looking at future applications in the oil and gas industry and even in border security. An interesting side note is that CRM GeoTomography is as much about data science as it is about muon detection. You can build a detector, place it in the ground and have it take a bunch of readings, but the real value is in using all that detector data to create a reliable, useable 3D map. The importance of data science skills to technology development is something we’re seeing more and more.

What advice would you offer to would-be entrepreneurs (or maybe intrapreneurs) in this sector?

There are a lot of resources that can help, not just in Canada or at TRIUMF but at facilities and institutions around the world, so my advice is to go looking for them. Pretty much every university and large laboratory will have some kind of technology transfer office that can help answer questions such as “How do I decide what the market might need?” or “How do I talk to potential clients about my technology?” We try to be proactive about this here at TRIUMF – my team is involved in a lot of research meetings to try to identify technologies that could be commercially interesting – but we also have researchers just walk into our office and say, “Hey, can I talk to someone about the idea I have?” We welcome them in, listen to their idea, help them determine whether they need to make an invention disclosure or whether there’s something that could be patentable, and also get them thinking about who might use their technology or whether there are industry partners who would be interested in licensing it. Just taking that first step of connecting with people is incredibly important.

US customers prepared to pay 40% more for cleaner electricity

Energy customers in the US would support price rises of 30-40% if billing information showed that their energy supply reduced emissions of both carbon dioxide and sulphur dioxide by 30%. That’s according to an online survey by US researchers, indicating that adding information on emissions reduction to energy bills could strengthen the customer base for cleaner electricity.

“Our work suggests that individuals can be willing to pay a premium if they know that their money is being used to support clean energy sources to address climate and health issues,” says Inês Azevedo of Carnegie Mellon University, US. “Making that link clear could go a long way to building support for lower emissions technologies.”

The survey also showed that an average respondent in the US would accept an increase of 19–27% in their electricity bill for an energy mix that supported a 30% reduction in emissions of either carbon dioxide or sulphur dioxide.

Azevedo and colleagues compiled the responses of 822 US citizens who were asked to compare different energy portfolios. The portfolios were presented as a bar graph showing the percentage of electricity generation coming from coal, natural gas, nuclear power or renewable sources. Using a randomized trial, the team investigated how varying information on climate and health aspects of emissions reductions affected respondents’ support and willingness to pay for alternative energy portfolios.

Respondents were recruited online from across the country and the self-reported demographics were found to be similar to that of the US population.

 In future work, the researchers are interested in seeing whether findings would be similar for energy customers in other countries.

“We would like to explore how factors such as actual air quality levels affect respondents’ values toward clean energy,” adds Brian Sergi, also of Carnegie Mellon. “China, for example, has struggled with extremely poor air quality in recent years, and we think it will be interesting to explore whether the salience of the air quality issue has helped to motivate stronger support for emissions reductions.”

The team believes that a better understanding of how the public values decisions in the electricity sector will bolster discussions on clean energy transition.

Azevedo, Sergi and colleagues presented the findings in Environmental Research Letters (ERL).

Topological superconductivity predictions tout graphene for quantum computing

Graphene may have seemed a poor candidate for any kind of correlated electron physics not so long ago, but studies of bilayer graphene revealed a twist in the tale. Experimenting with the angle of orientation between one layer and another, revealed both Mott insulating and superconducting  behaviour at different magic angles, and the potential for a new “twistronics” approach to engineering device properties. Theorists have been quick to snap up on the action with a recent paper suggesting more revelations to come.

“Graphene may become not only a venue for strong correlation physics, but also topological superconductivity,” suggest Cenke Xu at University of California, Santa Barbara, and Leon Balents at the Kavli Institute of Theoretical Physics, Santa Barbara, in the US in a recent Physics Review Letters report. Their theoretical treatment of the bilayer graphene systems points towards the existence of topological “Majorana” states at the edge of the material, of particular interest for quantum computing since they offer a system for quantum bits that is more robust to environmental perturbations than many others.

Three is the magic number of lattice sides

Following the experimental observations of superconductivity in bi- and multilayer graphene Xu and Balents aimed to “understand the nature of the observed superconducting phases”. They describe the twisted multilayer graphene as a superlattice with three-sided triangular lattice units much larger than the original honeycomb microscopic lattice. They then apply the “Hubbard model” – one of the simplest models for interacting particles in a lattice with just two terms in the Hamiltonian to describe the kinetic energy in terms of hopping from one site to another and the potential at the lattice sites.

“We argue that even in the simplest situation, the valley degree of freedom of graphene leads to dramatic modifications to the superconductivity: the preferred states are topological superconductors with a valley singlet structure,” explain Xu and Balents. “The compelling simplicity of the triangular framework suggests that graphene Moiré heterostructures which realize the single band triangular regime are favourable for realizing topological physics,” they conclude.

Among the recent work on this topic Noah F. Q. Yuan and Liang Fu a MIT published a report that also applied the Hubbard model to twisted bilayer graphene but based on a honeycomb lattice, leading to more intricate nuances in the results. Their work helps towards understanding the recent observations of transitions from metal to Mott insulator, Landau level degeneracy lifting, and unconventional superconductivity. What Xu and Balents add to the discussion is the potential for topological superconducting phenomena in these systems.

Full details are reported in Physical Review Letters.

Proton pulses accelerate electrons to 2 GeV

A beam of protons has been used for plasma wakefield acceleration for the first time, driving electrons to energies of 2 GeV over a distance of just 10 m. The technique was developed by CERN’s AWAKE collaboration and is still preliminary, but it could potentially accelerate fundamental particles to very high energies.

CERN’s Large Hadron Collider (LHC) accelerates protons to 6.5 TeV before smashing them together at a combined energy of 13 TeV. Protons are relatively heavy and comprise three quarks, which means that the collisions produce huge quantities of particles that must be detected and analysed.

While sifting through the debris of these collisions has led to important discoveries – including the Higgs boson – it is a complicated and data intensive process. As a result, some particle physicists have proposed that the next big collider after the LHC should use lighter, fundamental particles such as electrons and positrons. This would result in much “cleaner” collisions that produce far fewer particles.

The problem is that circular accelerators like the LHC are ill-suited to colliding light fundamental particles. Accelerating charged particles in curved paths causes them to emit synchrotron radiation, and light particles lose much more energy in this process than heavier ones. Therefore, most designs for fundamental particle colliders are linear. The International Linear Collider – proposed for construction in Japan – would need to accelerate electrons for over 11 km to reach 0.25 TeV.

Plasma surfing

Plasma wakefield acceleration offers a very differ way of accelerating electrons over much shorter distances. An intense pulse of particles or laser light is fired into a plasma, separating electrons from ions to create a huge electric field that propagates like a ship’s wake (the wakefield) behind the pulse.  If electrons are injected at precisely the right time, they can surf this wave and be accelerated to very high energies over relatively short distances.

Much as larger wakes can be created by larger ships, larger wakefields can be created in plasmas by using more energetic pulses. Previous experimental demonstrations of plasma wakefield acceleration have used either laser pulses or electron bunches to create the necessary wakefields. Unfortunately, the maximum energy that can be packed into a single laser pulse, for example, is around 1 J, which means complex, multi-stage accelerators would be required to accelerate electrons to the highest energies.

Protons, however, are relatively easy to accelerate and in 2009, Allen Caldwell of the Max Planck Institute for Physics in Munich and colleagues proposed that a 100 micron-long proton bunch could accelerate electrons to over 0.5 TeV in less than 500 m. There was one problem with this scheme – 100 micron-long, ultradense proton bunches do not yet exist.

Self-modulating bunches

The bunches from CERN’s Super Proton Synchrotron used by AWAKE are around 10 cm long so the team first fire a bunch into a plasma, which causes it to “self-modulate” into a series of shorter bunches. “These small bunches are shorter and denser,” explains AWAKE member Matthew Wing of University College London. “Their electric fields are completely in phase, so they constructively interfere to drive stronger and stronger wakefields.”

By injecting electrons near the back of the bunch, the researchers accelerated them to 2 GeV in just 10 m of plasma. “Our theoretical colleagues have shown that, if you take the LHC bunch as it is right now, you could accelerate electrons to roughly 1 TeV in just over 1 km and get to 6 TeV in about 8-10 km,” says Wing. “We need to do further R&D to demonstrate that it’s possible to get up to those high energies with excellent beam qualities but hopefully this will kick start people to think how this could be incorporated into a design for a future collider.”

Plasma physicist Sébastian Corde of Laboratoire d’Optique Appliquée in France is impressed: “This solves a lot of potential issues that we have in plasma acceleration,” he says. He cautions, however, that much work remains: “For every 2600 electrons injected, only one gets trapped into the plasma wave and accelerated…Clearly that’s something they’ll have to work on.”

Wim Leemans, director of the Berkeley Lab Laser Accelerator Center in California, adds “Having been in [plasma wakefield acceleration] for over three decades, I find it very important that CERN – the major high-energy physics lab in the world – has started investing in this technology”.

The research is described in Nature.

Fluorescent ‘flipper’ probe measures membrane tension

The tension of cell membranes (which are made of lipid bilayers) plays an important role in a host of biological processes, such as cell motility, endocytosis and cell division, but measuring this tension is no easy task. Researchers at the University of Geneva in Switzerland have now invented a new fluorescent push-pull probe to do just this. The device, which can accurately determine the membrane tension of live cells, might help in the development of many new biomedical applications, including the detection of cancer cells, which characteristically have very high membrane tension compared to healthy cells.

Cell membranes are fluid surfaces around 4 nm thick that surround a cell and prevent its contents from “spilling” out. Since the volume of a cell changes dramatically during everyday biological processes, cells have evolved to continuously monitor the tension of their membranes. For example, when the tension becomes too high, they increase the amount of lipid in the membrane. And when it becomes too low, they decrease it, which has the effect of “tightening” the membrane. Cell membranes are pretty resistant to stretching though and can withstand tensions of up to 10-2 N/m before breaking apart.

Important though it is, membrane tension is notoriously difficult to measure in cells. The only technique available today involves making measurements on small membrane tubes that have been extracted from the outer membrane of the cell (its plasma membrane). Although this approach has provided much valuable information in the past, it is complicated – both to perform and obtain results from.

A push-pull system: FliptR

The new probe, created by a team led by Aurélien Roux and Stefan Matile, works in a completely different way. Dubbed FliptR (for fluorescent lipid tension reporter), it consists of two large fluorescent flipper groups made of dithienothiophene molecules connected by a single carbon bond.

“This chemistry was designed by Matile’s group so that the two flippers are in a twisted configuration at rest,” explains Roux. “The molecule also has an electron donor group at one end and an electron group on the other end – which is why we call it a push-pull system.”

When the molecule is inserted into a cell, it partially untwists (“planarizes”) because of the pressure exerted by the lipid tails on the cell membrane. This untwisted structure increases the time it takes for the molecule to fluoresce (that is, the time it takes for electrons to transfer through the molecule). Since this fluorescent lifetime increases as the membrane tension of the cell increases, the researchers are easily able to quantify it using fluorescence lifetime imaging microscopy. Indeed, they have already produced florescent lifetime calibration curves for the membrane tension of two of the most commonly used cell lines in biology, MDCK and HeLa cells.

Access to internal membranes too

“The technique is an improvement on existing methods to measure tension that apply local force (using pipettes or optical tweezers, for example) to pull on the membrane and monitor the reaction,” says Roux. “These approaches are thus limited solely to the outer, plasma membrane. Our technique, on the other hand, allows us to image the membrane tension all over the cell and follow tension gradients and inhomogeneity,” he tells Physics World. “And last but not least, it allows us to access the internal membranes of organelles for the first time, so we could now start measuring their tension too.”

Indeed, researchers in Matile’s team say they are busy designing such internal membrane probes.

The research is detailed in Nature Chemistry 10.1038/s41557-018-0127-3.

3D printing facilitates complex spinal surgery

© AuntMinnieEurope.com
© AuntMinnieEurope.com

Dutch researchers have developed a workflow involving 3D virtual and 3D-printed models that may change how complex spinal surgeries are managed. Using this new technique, surgeons were able to repair a 12-year-old girl’s severe and debilitating spinal deformity.

In a technical report, first author Peter Pijpker and colleagues from University Medical Center Groningen outline how they constructed a 3D virtual model and 3D-printed model of the spine of a patient with a severe deformity. Clinicians used the 3D models to both preoperatively plan a challenging surgical treatment for the patient and intraoperatively guide the operation (World Neurosurg 10.1016/j.wneu.2018.07.219).

The 3D virtual planning and 3D printing technique was feasible for the surgery of a complex spinal deformity and may help improve clinical outcomes in the future, the authors noted.

3D-printed spine model
A 3D-printed spine model with 3D-printed osteotomy templates (red). (Courtesy: Pijpker et al. CC BY 4.0)

“The [3D-printed] templates and bone models provided valuable guidance during the osteotomy in the severely deformed anatomy,” they wrote. “Moreover, the surgeons report that studying the 3D anatomy in a multidisciplinary team facilitated the surgical procedure due to enhanced spatial orientation.”

Accurate planning

Pedicle subtraction osteotomy is a technically demanding procedure for repairing spinal deformities and is associated with a risk of major complications. The surgery is particularly challenging when dealing with severely deformed spines.

“Operations of the severely deformed spine call for new, more precise methods of surgical planning,” the authors wrote. “[Three-dimensional] technology can give rise to new possibilities for the surgical planning of spinal deformities.”

In a recent case, Pijpker and colleagues applied 3D technology not only to facilitate the surgical team as they planned the best course of action, but while they performed the operation as well. The case centred on a 12-year old girl with a combination of bone diseases — skeletal dysplasia and severe congenital kyphoscoliosis — that required the expertise of specialists from several different fields for surgical treatment.

The group began by acquiring MRI and CT scans of the patient’s spinal cord. Next, they segmented and reconstructed these CT scans and then created a 3D virtual model of the spine using 3D-modeling software (Mimics Innovation Suite, Materialise). Examining the 3D virtual model, they were able to plan the ideal way to complete the surgery — allowing them to prevent the patient’s spinal deformity from progressing any further and minimize the risk of future neurological deficit.

To guide the procedure itself, the researchers 3D printed the virtual model of the patient’s spine, and they additionally 3D printed individualized guiding templates that fit directly onto the bone. The 3D-printed templates helped direct the surgical chisel during the procedure and also ensured the spine would maintain its position while the surgeons were cutting away pieces of bone.

The production cost of the 3D-printed spine was approximately Euro 154, and the image segmentation and template design took the 3D printing specialists a full day of work to complete.

Successful correction

With the 3D-printed spine and guiding templates at hand, the surgical team was able to successfully resect the spinal deformity and close the separation. The young patient left the hospital eight days after surgery without any neurological deficit. Postoperative X-rays demonstrated the surgeons had properly corrected her spinal deformity.

Spinal deformity correction
Postoperative X-ray showing correction of the spinal deformity. (Courtesy: Pijpker et al. CC BY 4.0)

The authors described the following four key ways in which the 3D virtual model and 3D-printed models facilitated the operation:

  • Provided insight of case-specific anatomy
  • Helped in the identification of spinal bones during surgery
  • Allowed for the visualization of deformed bones and their relation to the spinal cord
  • Made sure the preoperative plan correlated precisely with the actual operation

One drawback of the technique was that intraoperative use of the 3D-printed models was limited to the first stages of the procedure. For the final step of the procedure, the surgeons had to temporarily replace the 3D-printed guiding templates with rods to further stabilize the spine. The investigators hope that subsequent template designs incorporate openings into which the surgeons can place the support rods. They also plan to assess the accuracy of using 3D-printed models for this surgery and the effect of doing so on patient outcomes, compared with other techniques.

“[Three-dimensional] virtual planning, 3D-printed spine models, and osteotomy-guiding templates have facilitated the performance of the osteotomy and may, in [the] future, contribute to safer spinal osteotomy procedures,” they wrote. “The presented method … might hypothetically reduce surgery time and preclude the need for intraoperative radiography, especially when combined with patient-specific drill guides.”

  • This article was originally published on AuntMinnieEurope.com © 2018 by AuntMinnieEurope.com. Any copying, republication or redistribution of AuntMinnieEurope.com content is expressly prohibited without the prior written consent of AuntMinnieEurope.com.

Mind the gap

If I were to ask you what could be considered a strong contender for “the most far-reaching technological breakthrough of the 21st century to date”, it’s unlikely your answer would be “graphene”. And yet that is the bold claim made by Brian Clegg in his latest book The Graphene Revolution: the Weird Science of the Ultrathin.

The so-called “wonder material” graphene is an atom-thick tessellated-hexagon lattice of carbon atoms, and was first isolated by Russian physicists Andre Geim and Konstantin Novoselov in 2004. The opening chapter of the book describes in vivid detail the now-popular story of the scientist duo’s regular “Friday night experiment” slots, levitating frogs and how the pair used a bit of sticky tape to create the first layer of graphene – work that led them to win the 2010 Nobel Prize for Physics.

Clegg looks into the history of atomic physics and also provides the quantum basis to a lot of the unique and bizarre material properties that graphene exhibits. But despite its title, it is only in the final chapter of the book that Clegg describes the actual applications that have utilized this wondrous material and one can’t help but feel as though the graphene revolution is far from its heyday just yet.

  • 2018 Icon Books 176pp £8.99pb

Negative carbon not on

A report by the European Academies’ Science Advisory Council (EASAC) evaluates the potential contribution of negative emission technologies (NETs) for removing carbon dioxide (CO2) from the atmosphere, in order to help meet the Paris Agreement’s climate targets. It says that NETs have “limited realistic potential” to halt increases in the concentration of greenhouse gases in the air at the scale envisioned in the Intergovernmental Panel on Climate Change scenarios. Even taken together, NETs did not have the potential to deliver carbon removals at the 12 gigatonne (Gt) per annum (p.a.) scale and at the rate of deployment envisaged by the IPCC.

The EASAC report concluded that “scenarios and projections that suggest that NETs’ future contribution to CO2 removal will allow Paris targets to be met appear optimistic on the basis of current knowledge and should not form the basis of developing, analysing, and comparing scenarios of longer-term energy pathways for the EU. Relying on NETs to compensate for failures to adequately mitigate emissions may have serious implications for future generations”.

The options looked at include reforestation, afforestation, carbon-friendly agriculture, bioenergy with carbon capture and storage (BECCS), enhanced geo-chemical absorption, ocean fertilization, and direct air capture and carbon storage (DACCS), i.e. extraction of CO2 direct from the atmosphere using absorbents and then the separation and storage of CO2.

…the implication is that we need to accelerate renewables and energy efficiency, these surely being a better bet than trying to (re) bury carbon.

Dave Elliott

The IPCC had looked to BECCS in particular, suggesting, in one scenario, that it could capture up to 3.3 Gt of carbon p.a. But the land-use and eco-implications of that are huge and, like the other carbon capture options, it would take a long time to have an impact. What’s more, since CCS was not developing as fast as had been hoped – see below and my next post – the prospects of BECCS now looked limited. EASAC says: “The loss in momentum in implementing CCS technologies not only has serious implications for mitigation pathways, but also one of the most commonly cited NETs (BECCS) assumes the availability of cost-effective ’off-the shelf’ CCS, while another (direct air capture) relies on the widespread availability of CO2 storage”.

Although the potential of direct air capture was put at 3.3 Gt p.a, or more, it was, so far, undeveloped, with just two prototype projects. If it was to expand on a significant scale, EASAC asked, who would pay for it? Turning CO2 into a valuable fuel, the CCU (or DACCU) option, i.e. CO2 utilization rather than storage, might offset the cost, but EASAC does not look at that since it is not a carbon negative option – the resultant synfuels would be burnt, releasing CO2. However, the report does say that fossil CCS, although not carbon negative, could cut emissions by 4 Gt p.a. from fossil fuel-fired plants.

Afforestation and reforestation could capture up to 3.3 Gt and new farming practices and the use of biochar – made from biomass – to retain CO2 in soil could help (2–3 Gt p.a), but “we remain in an era where deforestation and soil degradation are continuing to add substantial quantities of GHGs [greenhouse gases].” So, though growing trees is cheap and better soil management techniques are available, making net positive carbon gains will be hard.

Advanced geochemical “weathering” – adding carbonate or silicate minerals such as olivine and basalt to oceans and soils – has promise and may, EASAC says, offer 1 Gt C absorption p.a. Ocean fertilization with ferric compounds, to increase phyto-plankton productivity and CO2 absorption, could also capture perhaps up to 1 Gt p.a., if done on a vast scale, but that could have unknown, though potentially large ecological impacts.

So what’s the bottom line? Taken together, the EASAC report says, NETs and fossil fuel CCS might in theory eventually offer up to a total of around 12 Gt C capture p.a. but in practice nothing like this would be viable ecologically, quite apart from the economic costs. Even 10 Gt would be a very high maximum, given the technical limitations and land-use conflicts. And for the moment, CCS seems to be off the agenda and NETs look a long shot: trees apart, few of them exist beyond the R&D, test and/or prototype level and some are just concepts. John Shepherd at the University of Southampton, UK, an author of the report, said: “Negative emissions technologies are very interesting but they are not an alternative to deep and rapid emissions reductions. These remain the safest and most reliable option that we have.”

Moral hazard

All of which led the EASAC president Thierry Courvoisier to warn that: “Whether consciously or subconsciously, thinking that technology will come to the rescue if we fail to sufficiently mitigate may be an attractive vision. If such technologies are seen as a potential fail-safe or backup measure, they could influence priorities on shorter-term mitigation strategies, since the promise of future cost-effective removal technologies is politically more appealing than engaging in rapid and deep mitigation policies now. Placing an unrealistic expectation on such technologies could thus have irreversibly damaging consequences on future generations in the event of them failing to deliver. This would be a moral hazard which would be the antithesis of sustainable development.”

However, the EASAC report does accept that some of the technologies “can make some contributions to remove CO2 from the atmosphere even now, while research, development and demonstration may allow others to make a limited future contribution. We thus conclude it is appropriate to continue work to identify the best technologies and the conditions under which they can contribute to climate change mitigation, even though they should not be expected to play a major role in climate control at the present time.”

So, given the uncertainties with NETs and their likely significant impacts, it says that we have to strive as hard as possible to mitigate emissions, for example “through energy efficiency and energy saving by technical and regulatory measures, rapid deployment of renewable energies, land use management, reducing emissions of other GHGs etc.,” so as to meet emission reduction targets and to make any need for NETs more manageable.

The basic message of this study is thus that, in the main, we need to look elsewhere for a way to cut carbon. There are other options, nuclear being one, but given its problems, the implication is that we need to accelerate renewables and energy efficiency, these surely being a better bet than trying to (re)bury carbon.

Fossil CCS, although not carbon negative, is still being promoted by some. The Global CCS Institute says that “CCS is needed because the amount of fossil fuels we burn continues to rise”. It claims that “CCS is not a ‘front’ for the coal or wider fossil fuel industry” and sees CCS and renewables working together, although it also quotes some very low potential contributions for renewables.

However, renewables are booming while the prospects for CCS do not look good. There are just two coal CCS power station projects working at present, the $1bn Petra Nova project in Texas, US, and the $1.5bn Boundary Dam project in Canada. But, apart from the high cost, the final capture rates are low (33% in the case of Petra Nova) and energy requirement are high (25% of the plant’s output in the case of Boundary Dam). What’s more, the captured CO2 is being used for enhanced oil recovery (squeezing extra oil out of low-productivity oil wells), which means that, quite apart from any leaks, CO2 will be produced again when the oil is burnt. Full CCS, with the CO2 kept in geo-storage, would avoid that and could be carbon neutral, but as I will explore in my next post, CCS development work has all but halted, and although Australia has been looking at this idea, fossil CCS does not look likely to spread. With, as subsequent posts will describe in more detail, the various NETs, like BECCS and DAC, also mostly looking less than overwhelming, we may have to look elsewhere for solutions to our climate problems.

Chaotic cavity boosts stability of high-power laser

Unwanted fluctuations in the output of high-power lasers can be reduced by using a laser cavity that allows light to bounce around chaotically. That is the counterintuitive conclusion of scientists in the US, UK and Singapore, whose research could also boost our understanding of weather patterns and turbulent fluid dynamics.

High-power lasers have an immense range of applications, from materials processing to surgery, but keeping light emission stable is difficult. Complex non-linear interactions of a laser’s active medium with the light field can lead to chaotic fluctuations that degrade its output and reduce its usefulness. Researchers have tried to suppress these fluctuations, but this can restrict the laser’s power.

An ideal laser would transmit all its power at a single frequency, with all its wavefronts perfectly parallel. In reality, however, the desired longitudinal modes in a traditionally-shaped laser cavity inevitably excite transverse modes as well.

Making waves

“It’s like a ship propagating through water,” explains Ortwin Hess, a theoretician at Imperial College London specializing in quantum nanophotonics: “You’ve got waves pushed in front of it and waves pushed aside created in the wake.”

Narrow laser cavities supporting only one transverse mode generally remain stable. High-power lasers, however, require large laser cavities and, within these, multiple transverse modes can pile up, leading rapidly to chaotic fluctuations in the light output.

Attempts to tame these fluctuations have focused on suppressing these multiple transverse modes to make the cavity field resemble that of a small laser. Such strategies can be moderately successful, says Hess, but the cavities remain inherently unstable.

“The characteristic thing about a semiconductor laser is that, within the semiconductor active material, light and matter interact quite intimately,” explains Hess. “It’s a bit like the light changing the viscosity of a very viscous fluid while propagating through it.” Injecting a stable control pulse, for example, may successfully suppress the multiple transverse modes at one pumping current, but increasing the current further may cause them to reappear.

Sweeping-up instabilities

In the new research, Hess and his colleagues at Imperial joined forces with researchers at Yale University and Nanyang Technical University in Singapore. The team took the opposite approach and maximized the number of modes in a semiconductor laser. They produced a D-shaped cavity without longitudinal or transverse modes. Instead, light bounced around chaotically. The fluctuations in the properties of the semiconductor were therefore effectively random and below the scale of the wavelength. This prevented large-scale instabilities from forming, sweeping-up instabilities from the light field and spreading throughout the laser.

Amazingly, this resulted in a laser cavity that, macroscopically, was inherently stable independent of pump power and could emit light at multiple frequencies simultaneously without its output succumbing to unstable fluctuations.

“We don’t have to inject anything,” says laser physicist Hui Cao, who led the Yale group. She adds, “Instead, we design the cavity shape to eliminate instabilities.” Hess compares this approach of stability through sub-wavelength chaos to the reduced likelihood of tornadoes to form in hilly regions than over flat country.

Focus on industry

Some issues remain, however. Although the laser’s output profile is highly stable, its beam cannot yet be very tightly focused. Cao says this is not necessarily a problem for applications such as machining and material processing: “For those applications, what’s important is to produce a particular beam profile”. She adds, “People have used a Gaussian beam shape and converted it to a line, a square or a triangle because they want to write that pattern onto their device. They do not require very good spatial coherence because the shape is larger than the diffraction limit, and relatively broad bandwidth is also not a big issue. What they do need is the intensity and beam-shape stability.”

The researchers believe their cavity design should be applicable to many laser types, which can all suffer from similar instabilities at high powers. Beyond this, they believe there could be applications to the study of chaotic and unstable behaviour in other systems: “We’re trying to reach out to other communities to see whether our scheme could be used to suppress spatio-temporal instabilities in other non-linear wave dynamic systems,” says Cao. “Fundamentally the equations are the same.”

“Random or chaotic resonators has been an active field for some time in optics and photonics, but it was mostly fundamental research,” says semiconductor physicist Alessandro Tredicucci of University of Pisa in Italy. “This is clearly a situation in which a chaotic cavity has some potential benefits over a conventional laser cavity.” He cautions, however, that “You have to put more power in to get all these modes lasing at the same time, which lowers the efficiency and means that typically these chaotic lasers have lower performance than conventional ones.”

The research is described in Science.

Innovation: patent applications review

A round-up of the latest international patent applications in medical imaging.

Fusion images guide interventional procedures

GE has developed a system that obtains fusion images of a patient’s anatomy for use in guiding interventional medical procedures (WO/2018/112063). The technique fuses fluoroscopy images taken during the interventional procedure with pre-operative CT angiography (CTA) images, in real-time. This enables the operator to see the anatomy in the fluoroscopy image without having to inject contrast agent. To correct for anatomical deformation due to the insertion of interventional devices, a 3D ultrasound image is obtained after insertion and used to correct the pre-operative CTA images and provide the current vascular anatomy. This updated CTA image is fused with the intra-operative fluoroscopy images to provide an accurate 3D roadmap image that matches the deformed anatomy.

Time-of-flight detects, corrects PET/CT misalignment

Philips has devised a scheme for using time-of-flight (TOF) to detect and correct misalignment between PET imaging data and the attenuation map in PET/CT images (WO/2018/127470). The described device performs TOF image reconstruction (which utilizes the TOF localization of the PET imaging data) on PET data to produce a TOF-reconstructed image. Non-TOF image reconstruction, which does not utilize the TOF localization, is also performed. The device then computes a comparison image, which indicates differences between the TOF and non-TOF reconstructions. An adjustment – such as alignment correction of an attenuation map – is determined based on the comparison image. The TOF image reconstruction is then repeated on the PET data with the determined adjustment, resulting in an adjusted TOF-reconstructed image.

Ultrasound delivers non-invasive blood pressure measurement

Physio-Control has described a method and apparatus for non-invasive measurement of instantaneous blood pressure using pulse wave velocity (WO/2018/136135). A measurement component containing one or more sensors (such as ultrasound sensors) is fixed to the patient near to a blood vessel. This device simultaneously measures the vessel’s pulse wave velocity and the instantaneous blood velocity within the vessel. It then computes the instantaneous blood pressure of the vessel using, for example, the Waterhammer equation. The filing notes that the sensors may be contained in a disposable patch or co-located with another sensor, such as a patient monitor.

X-ray device generates multi-energy images

Varian Medical Systems has published details of a device for multi-energy X-ray imaging (WO/2018/132284). The system includes an X-ray source, which generates a series of individual X-ray pulses with different energy levels, and an X-ray imager that detects the received X-rays for generation of a composite image. It also incorporates a generator interface box (GIB) that controls the source to provide the series of individual X-ray pulses and synchronizes detection with pulse generation. The GIB controls these processes to optimize image generation while minimizing unnecessary X-ray irradiation.

OCT provides low-cost central nervous system characterization

Researchers at the University of Coimbra have created a data processing method for characterizing the health status of the central nervous system, based on non-invasive optical coherence tomography (OCT) of the retina (WO/2018/127815). The technique involves processing OCT fundus imaging data to compute a texture parameter(s), and then classifying the texture parameter(s) into a central nervous system health status. The method, which uses a low-cost and compact acquisition device, overcomes the need for expensive and complex MR and CT instrumentation to assess central nervous system status in humans and animals. It enables classification of healthy controls and patients into the correct group and monitoring of longitudinal changes, in a fraction of the previous time and at lower cost.

SPECT images processed with improved resolution isotropy

A method for processing a SPECT image with improved resolution isotropy is disclosed by Molecular Dynamics in patent application WO/2018/146691. The image is obtained using at least one gamma detector that detects gamma radiation emerging from the region-of-interest at multiple detector configurations. The method includes: obtaining data indicative of the detector configurations and their spatial relationships to the region-of-interest; using these data to determine a resolution level for each of a number of directions in each point in the image; and processing the image based on the determined resolution levels.

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