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Home » Page 692

Hydrogel to repair heart proves safe to inject in humans

Currently, there is no established treatment to repair damage to cardiac tissue following a heart attack, where the resulting scar tissue can diminish muscle function and cause heart failure. Ventrix, a University of California San Diego spin-off, has now successfully conducted a first-in-human trial of an injectable hydrogel – VentriGel – designed to repair damage and restore cardiac function in heart failure patients who previously suffered a heart attack (JACC Basic Transl. Sci. 10.1016/j.jacbts.2019.07.012).

The FDA-approved Phase 1 clinical trial is the first to test a hydrogel designed to repair cardiac tissue. It is also the first demonstration of using a hydrogel made from extracellular matrix (ECM), the natural scaffolding in which cells reside, in any tissue in patients. This is significant as preclinical studies have shown ECM hydrogels to potentially be effective for other conditions, such as poor blood circulation caused by peripheral artery disease.

Invented by Karen Christman at UC San Diego and her team, VentriGel is made from cardiac connective tissue taken from pigs and stripped of heart muscle cells. The decellularized tissue is then freeze-dried and milled into powder form, and then liquefied into a fluid that can be easily injected into heart muscle via a minimally invasive procedure. Once it reaches body temperature, the liquid turns into a semi-solid, porous gel.

After injection into damaged cardiac muscle, VentriGel forms a scaffold that acts as a reparative environment to which healthy cells migrate. This results in increased cardiac muscle, reduced scar tissue and improvements in heart function.

The primary aim of the trial was to evaluate the safety and feasibility of transendocardial injections of VentriGel in patients with moderate left ventricle dysfunction following a heart attack. The team examined seven patients who had suffered a heart attack within the past year, and eight who had a heart attack one to three years previously.

Each patient received up to 18 injections of VentriGel into the damaged region, via a catheter guided by a cardiac mapping system. The researchers followed the patients for six months after treatment and found that the hydrogel could be safely injected into the patients. Overall, VentriGel was well tolerated, with all patients completing the full follow-up. The team report that no adverse event was definitely related to VentriGel or the mapping/injection procedure. One major and one moderate adverse cardiac event, both in the first patient treated, were possibly related to the treatment.

A secondary objective was investigation of the preliminary efficacy of VentriGel, by measuring changes in various parameters from baseline to three and six months after treatment. For example, patients performed a six-minute walk test as a measure of functional exercise capacity. In the total cohort, VentriGel treatment significantly increased the maximum walk distance with time post-injection. The patients also took a heart function assessment and a heart health questionnaire, as well as undergoing MR imaging, at baseline and three and six months later.

“Although the study was designed to evaluate safety and feasibility and not designed to show whether VentriGel effectively helps improve heart function, we observed some improvements in patients,” explains Christman. “For example, patients could walk longer distances. We also observed signs of improving heart function in patients who experienced a heart attack more than one year prior to treatment.”

Ventrix is now gearing up for a Phase 2 clinical trial that will expand on this successful first-in-human study. The team is planning a larger, randomized trial that will evaluate how effectively VentriGel can improve cardiac function and quality-of-life for patients experiencing heart failure.

Stepping stones to space

Libby Jackson
Space stories: Libby Jackson speaking at this year’s Bluedot Festival in the UK. (Courtesy: Carousel PR)

When she was eight years old, physicist-turned-engineer Libby Jackson penned and illustrated a “travel guide to Mars”. Part of a school assignment set over the summer holidays, she was meant to research a place that she someday hoped to visit. Jackson decided upon a rather more liberal interpretation of the assignment, as she dreamed of a terraformed Martian surface, teeming with “an amazing selection of hotels you could stay at [and] also plenty of marzipan and Mars bars to go around”. Space has been a life-long passion for Jackson and today she is the human exploration programme manager for the UK Space Agency.

“My interest has always been in space, but when I was younger, I didn’t know that the UK had a space industry or that you could possibly be an engineer or a scientist working in that field,” says Jackson. Indeed, it was only when she spent a week of her summer holidays at Space School UK at the age of 16, that she learnt about the many different roles, beyond that of an astronaut, that the space sector affords. Jackson went on a visit to what was then Matra Marconi Space company in Bristol, which later became Astrium, and subsequently Airbus. “I clearly remember my fascination that day, seeing real space hardware and satellites that were being built here in the UK. That was when I had the first inkling that perhaps one day this might be something I could do. But at the time, my focus really was on my impending GCSEs and then A-levels and on to university. So while the seeds were sown, I still couldn’t really see how I’d get there just yet.”

In fact, this is something that Jackson is keen to tell students today, who may have a “big crazy dream” but might not know how to fulfil it. “When you are at university, and you look at people you admire or who are doing jobs that you want – know that none of these people would have known how they would get there either, when they were 15. You may be able to look back and see the path, but for now it’s just a series of stepping stones. Just look for the lily pad or the next stone that seems interesting to you, and if you’re enjoying it, then that’s the right way.”

When you are at university, and you look at people you admire or who are doing jobs that you want – know that none of these people would have known how they would get there either, when they were 15

For Jackson, the next life-changing step came a year later aged 17, when she had to organize a week of work shadowing. On a whim, Jackson and a friend used the latter’s e-mail account (few people had e-mail access at the time) to contact NASA, and by some stroke of luck, she and the friend were invited to spend two weeks at the Johnson Space Center in Houston, US. “We saw the neutral buoyancy lab where they trained astronauts. We even got into the building where they house all the Apollo lunar rocks, and to this day, I’ve not seen those since.” But what Jackson remembers most from that trip is the time she spent at mission control. “I sat next to Kathy Larson, who was working on a propulsion systems console – she was shuttle flight controller, and they were running simulations for shuttle launches and aborts. And I just put the headset on, and I thought, ‘This is it…this is where I want to be.’ ”

After getting her A-levels in physics, maths, further maths and music, Jackson did a BSc in physics at Imperial College, London. She then enrolled for a Master’s in aeronautics and space engineering at Cranfield University in 2002. Between the two degrees, Jackson did a summer placement at EADS Astrium (now Airbus), working with a team on synthetic-aperture radar imaging – indeed, her thesis research was also done with the group. At the end of her degree, the same group offered her a job. “While the work was interesting for a summer, it just didn’t excite me enough, so I turned them down, with nothing else on the horizon,” says Jackson.

As it happened, this was the right decision – Jackson put together a CV, which stated that she was looking to work specifically in mission control and operations, and sent it to a variety of graduate schemes and several of the space companies in the UK. “In the end, it was Astrium that invited me for an interview. It turned out that they were looking for graduates to work in a team to develop a satellite operations centre, and this became my first job.”

I want young people to know that the space sector can be a welcoming place, no matter your gender, race or sexual orientation

Jackson spent the next three and a half years at Astrium as an operations engineer. Despite being one of only two female engineers in her team at the time, she always felt welcome. “I’ve been lucky. I certainly hear horror stories about academia and engineering, but I think the space sector is a bit different. That’s a very important message I’d like to get out. I’m not for a minute pretending that sexism isn’t an issue in the sector, but I want young people to know that this can be a welcoming place, no matter your gender, race or sexual orientation.”

Variety of life

Around 2007, once Europe became part of the International Space Station (ISS) and the Columbus science lab module was to be launched, Jackson moved to Munich and became an instructor at the Columbus Control Centre, and spent the first year and a half training flight controllers. A few years later, the opportunity arose for her to become a flight director, and she jumped at the chance.

So what’s a day in the life of a flight director like? “Well, every day is different, as you’re making decisions and problem-solving, while working with an amazing team of very talented people. There were daily science experiments to be run, and there might be some maintenance to do. Always, we had to keep the crew safe, keep the vehicle safe, and then get on with the mission. The mantra for mission control is crew, vehicle, mission. And you do all of this while working at the forefront of human exploration.”

Today, Jackson works at the UK Space Agency, leading the country in human space exploration. “I work with our astronauts, and on the science that goes on at the ISS. I work with academia and industry to make sure everyone can make the most of the UK’s space endeavours.”

At the end of this year, the European Space Agency (ESA) – which the UK will still be a member of post-Brexit – will host a meeting of all its member states, to agree on future programmes and funding. “The decisions that will be made at the end of this year should see ESA commit to part of the lunar gateway and the return of humans to the Moon, and part of the mission to return samples from Mars. The UK is hoping to be a part of these, and my job is to be writing the business cases that will be put to the UK Treasury, to make the case for the UK’s investment in these missions.”

Jackson is emphatic that the space sector is thriving. “We need people to join in, and physics is an ideal route into it, as you’ve seen from my story. Whether that’s getting into space to do research, or whether it’s any one of the many other roles, there’s something for everyone.”

Water vapour is spotted on a distant rocky planet

Water vapour has been detected in the atmosphere of a rocky planet 110 light-years from Earth. Called K2-18b, the planet orbits within the habitable zone of a red-dwarf star, which means that the planet could harbour life. The observations were made by astronomers at University College London, who used the Hubble Space Telescope. While the evidence for water vapour is compelling, the scientists say that the next generation of telescopes will be needed to gain a better understanding of the planet’s atmosphere.

Astronomers know of thousands of extrasolar planets – planets that orbit stars other than the Sun. As observation methods improve, scientists are beginning to study the atmospheres of some of these planets. Evidence for water in the atmospheres of distant gas giants – planets that resemble Saturn or Jupiter – has already been found, but this is the first time that water has been spotted in the atmosphere of distant Earth-like planet in the habitable zone of its star. This zone is a band of orbits in which liquid water – and possibly life – could exist on a planet.

K2-18b is not, however, identical to  Earth. It is a “super Earth” that is eight times the mass of our world and completes one orbit of its star in just 33 Earth days.

Spectroscopic signature

Hubble’s Wide Field Camera 3 was used to observe eight transits of K2-18b. A transit occurs when a planet passes between the Earth and the planet’s companion star and results in a small drop in the amount of starlight that reaches an observing telescope. Some of the light that does reach the telescope during a transit has passed through the planet’s atmosphere and this light can be analysed for the spectroscopic signature of water.

The team analysed the spectroscopic data using three atmospheric models of K2-18b. The first model described the atmosphere as cloud-free and comprising only water, molecular hydrogen and helium. The second model was like the first but with the addition of molecular nitrogen. The third model included clouds, water, molecular hydrogen and helium.

Their analysis reveals a slight preference for the first model, but the likelihood of all three models have about the same statistical significance.

Is the Earth unique?

Angelos Tsiaras, who led the research, says “Finding water in a potentially habitable world other than Earth is incredibly exciting. K2-18b is not ‘Earth 2.0’ as it is significantly heavier and has a different atmospheric composition. However, it brings us closer to answering the fundamental question: Is the Earth unique?”

Team member Ingo Waldmann adds “With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets”.

Astronomers seeking further insight into the atmosphere of K2-18b may have to wait until the next generation of telescopes come online. Team member Giovanna Tinetti says, “Our discovery makes K2-18 b one of the most interesting targets for future study”. She adds, “Over 4000 exoplanets have been detected but we don’t know much about their composition and nature. By observing a large sample of planets, we hope to reveal secrets about their chemistry, formation and evolution.”

The observations are described in Nature Astronomy.

An independent measurement of water vapour on K2-18b has also been made by Björn Benneke of the University of Montreal and colleagues. This team also used the Wide Field Camera 3 and they describe their observations in a preprint on arXiv.

Crocker Nuclear Laboratory to explore production of rare medical isotope

The Crocker Nuclear Laboratory at the University of California, Davis, has received a $340,000 grant from the Department of Energy to manufacture the rare isotope astatine-211 (211At) for potential use in cancer treatment.

211At decays via emission of alpha particles, which travel less than a millimetre in human tissue. This makes it an ideal candidate for targeted alpha therapy, a treatment that delivers radiation directly to cancer cells and minimizes irradiation of healthy tissue. Unfortunately, 211At is not currently available in large enough amounts for clinical testing. Additionally, the isotope’s short half-life of 7.2 hr means that it must be generated and used in the same day.

The new project will test the feasibility of producing 211At at the Crocker Lab’s cyclotron — the main magnet of which was originally part of the UC Berkeley cyclotron used to discover astatine back in 1940.

“We are excited to again make medically useful isotopes at the Crocker Nuclear Laboratory,” says lab director Eric Prebys. “It’s exciting to find new uses for this cyclotron, particularly one that calls back to its origins.”

The scientists will produce 211At by bombarding bismuth-209 with alpha particles. They note that the Crocker Lab’s 76-inch cyclotron, which began operation in 1966, is one of the few in the USA that can produce an intense enough alpha particle beam to create 211At. It achieves this by using a magnetic field to guide charged particles along a spiral path and accelerate them to high energies.

The Crocker Lab has extensive experience in creating medical isotopes. In 1972, UC Davis scientists developed a new method for making iodine-123, a thyroid cancer diagnostic tool now available commercially. The lab has produced nearly 25 different medically useful isotopes over the years, but the cyclotron has not been used to produce isotopes since the 1990s.

The Department of Energy grant will fund the design and construction of new equipment to prove the feasibility of production and recovery of 211At at the Crocker Lab. In future, Prebys and colleagues plan to seek funding for full-scale production of the isotope.

US scientific societies warn security policies pose a danger to science

A group of 60 US scientific societies, including eight physics-related organizations, have joined forces to say that the American government’s efforts to strengthen national and economic security is endangering scientific research. In a letter sent last week to US presidential science adviser Kelvin Droegemeier and science-related government agencies, the societies say that policies intended to reduce security risks will end up harming science. The letter calls on the recipients to ensure that the US “remains a desirable and welcoming destination for researchers” as the government develops its policies.

Coordinated by the American Association for the Advancement of Science, the letter follows reports that the FBI and other security agencies have investigated scientists suspected of working — directly or indirectly — for overseas governments, especially China. Some US university science departments have already sacked Chinese nationals, while Americans of Chinese origin have come under suspicion of spying for China. In June, the US Department of Energy (DOE) also said it would ban scientists from taking part in recruitment programmes sponsored by foreign governments, such as China’s 1000 Talents initiative. The clampdown extends to individuals working for the DOE’s contractors, meaning that around 100 000 individuals are affected.

[Government agencies have offered] compelling anecdotal evidence of [espionage] cases that have impacted industry, classified research, and applied research

American Physical Society statement

“We were aware from discussions with our member societies and broader dialogue with scientific societies that the [security policies are] a matter of concern,” says Michael Moloney, chief executive of the American Institute of Physics, which was among the societies that signed the letter. “It’s also reflected in statements by presidents of some of the leading research universities.” Moloney believes, however, that the US government does recognize the issues expressed in the letter. “The leaders of federal agencies that I personally have spoken with are very cognizant of the concerns of the scientific community and of the need for broad consultation with stakeholders,” he adds.

The American Physical Society, which is also a signatory, concedes in a separate statement that government agencies have offered “compelling anecdotal evidence of [espionage] cases that have impacted industry, classified research, and applied research.” However, the society’s statement continues, it will “continue to make the case that security concerns must be balanced against the value of keeping the scientific enterprise open and collaborative”.

Wind power in the UK

After an initially slow start in the 1980s and 1990s, when it lagged far behind the pioneers – Denmark and then Germany – the UK has done quite well on wind energy. That’s not really surprising since it has about the best wind resource in the world, in Scotland especially. Now the UK has reached around 21.5 GW, including 8.5 GW offshore, and leads the world in offshore deployment.

More offshore wind is planned and with prices falling, to around £50/MWh in recent French auctions, the next round of the UK’s Contract for Difference (CfD) competitive auction subsidy scheme may see up to 6 GW added. Meanwhile, several already-agreed projects are in the pipeline, e.g. the 588 MW Beatrice deep water array should be on-line soon.

The UK is also host to two floating offshore wind projects. The still-being-developed 10 MW Dounreay Trì Floating Wind Demonstration Project, 10 km off Thurso, with two machines mounted on a Hexicon triangular platform, and the 30 MW Hywind scheme, billed as the world’s first commercial wind farm. Five machines have now been installed on spar buoys 29 km off Peterhead, Scotland. It has been doing well.

Floating devices can be installed far out to sea at sites with water depths that would make sea-bed fixed systems impossible or prohibitively expensive. It looks like the way to go longer term, with a Floating Wind Action Group set up through trade body RenewableUK, in partnership with Scottish Renewables, to press the case for large-scale use of the technology.

Scaling up

Meanwhile, device size for offshore machines is increasing dramatically. The world’s biggest wind turbine so far, GE Renewable Energy’s 12 MW Haliade-X, is to undergo UK testing before it enters production in 2021. It’s claimed that it will achieve an annual operating capacity factor of 63%, well above the 30-45% reached by most existing offshore machines, although the 402 MW Dudgeon wind farm, 32 km off  Norfolk, claimed 65% last year.

The UK government has confirmed a sector deal with the offshore wind industry to help it reach 30 GW of installed capacity in UK waters by 2030, with a new £100 m boost over 10 years recently announced. The government aims to support investment in the supply chain and energy infrastructure, and work with further education institutes on skill development and retraining, enabling workers to move between offshore energy sectors. It wants to increase the number of skilled jobs in the UK offshore wind sector from 7,200 to 27,000 by 2030. The government has also challenged the sector to ensure women hold at least 33% of these jobs by this date, with an ambition of reaching 40%, up from 16% today. The sector deal also aims to help the UK offshore wind industry boost global exports five-fold to £2.6 bn a year by 2030.

It does all look very positive. Certainly much more than 30 GW capacity is seen as possible, with Greenpeace looking to 45 GW by 2030 and an industry representative talking about 50 GW by 2050. Indeed some say offshore wind could even dominate UK energy supply.  And with sites now extending 100 miles or more offshore, for example for the Dogger Bank project, visual intrusion from land is not going to be an issue.

Onshore wind lags

The UK onshore wind story, however, is less good. New projects are still going ahead, with 598 MW added in 2018, but that was down from 2,666 MW installed in 2017. Support has been blocked following the Conservative government’s view that, as then energy minister Claire Perry re-confirmed recently, “we do not believe that more large-scale onshore wind is right for England”, with no access being allowed to the CfD, and tighter planning rules imposed.

Although there can still be local opposition to some projects, and opposition from the likes of the Global Warming Policy Foundation (see my earlier post), around 79% of the public supported onshore wind in the latest UK government Department for Business, Energy & Industrial Strategy (BEIS) national poll. Environmental lobby groups have been pushing for a rethink.

So has trade lobby RenewableUK. It has claimed that 4.5 GW of new onshore wind capacity was “shovel ready”, with local planning permission already obtained, and that it ought to be allowed CfD access. Onshore wind may not need subsidies as it’s now one of the lowest cost renewable options, but the CfD system offered the main route to market. RenewableUK also warned that new policies were needed to support repowering/replacing/updating existing onshore wind projects. Otherwise 8.27 GW, nearly 20% of renewables capacity, could be retired over the next 20 years. RenewableUK’s “optimum scenario”, with more powerful turbines, has 12 GW of replacement onshore wind. At the very least, the organization wanted commitments to maintain the current onshore capacity, pointing out that it is the cheapest option and that “the public mood is for more urgent action to tackle climate change and this is a concrete example of where government can act to avoid backsliding on progress against our carbon reduction targets”.

Beyond that, the case for expanding onshore wind does look very strong, given its low cost. A study by Vivid Economics for RenewableUK says expanding onshore wind from 13 GW today to 35 GW by 2035 would reduce the cost of electricity by 7% compared with other expansion options: a boom in onshore wind could, it claimed, cut energy bills by £50 a year compared to a high-gas energy mix.

The pressure for a rethink has built up from Conservatives too. And from business. In a letter to the business secretary Greg Clark, the Confederation of British Industry (CBI) said, “we must see action to unblock the substantial pipeline of onshore wind projects ready to be developed and built in parts of the country where they receive public support, such as Scotland”. It added that “hindering the continued deployment of the cheapest form of renewable electricity is hampering the goal of decarbonising at the lowest cost”. But it also thought nuclear might be viable “at the right price”.

The UK government Select Committee on Science and Technology thought the same and, while backing limited nuclear renewal, was adamant that “the Government must ensure that there is strong policy support for new onshore wind power”. It also backed re-powering older existing onshore wind projects with the most efficient technology, if there was local support.

Doing well in Scotland

While we await a government response to that, the situation for onshore wind is still a little grim, with expansion slowed. Though none of this means that some wind projects are not doing well, especially in Scotland. For example, Scottish Power’s Whitelee onshore wind farm near Glasgow, the UK’s largest, with 215 turbines, has been operating very successfully, with upgrades planned. It’s now set to have a “super battery” installed with 50 MWh of capacity. The kit will be able to reach a full charge in under an hour. It will allow excess power to be stored at times when demand is low or wind turbine output is high, for instance at night. This stored excess can then be released at times of higher demand and low wind. It will also be used to provide “bursts” of power to help stabilize the UK grid on a second-by-second basis.

That is good news, and there has been a concession on small projects on remote islands in Scotland. But overall, with exceptions, UK onshore wind development is mostly stalled — a far cry from what’s happening elsewhere in Europe. For example, in Germany although onshore capacity growth has slowed a little recently, the country now has over 53 GW. And, looking to the future, the EU-wide onshore 2050 potential has been put in a new German study at a massive 13.4 TW. That’s sufficient, if it could all be developed, to supply ten times EU power needs, at under €60/MWh and some at below €40/MWh. Another new study put the EU theoretical site potential for 2050 even higher, at a gigantic 52 TW. That is very speculative, and assumes the UK plays a role. Given the price falls, arguably the nation really should join the global boom – there’s around 95 GW of onshore wind capacity now in place in the US, and over 180 GW in China, with more planned. The UK does seem to be missing out on this with, for the government, Lord Henley offering the explanation that “the opportunities for the price of offshore wind coming down are surely far greater than for onshore wind, because of the scale of the windmills that one can build at sea, compared to on land. We have no plans to review that policy”.

PET/CT-guided chemoradiotherapy improves lung cancer outcomes

The use of 18F-fluorodeoxyglucose (FDG) PET/CT for tumour staging and treatment planning can improve outcomes for patients with lung cancer. In particular, using PET/CT for radiotherapy target volume delineation (TVD) can increase the treatment accuracy, especially in cases when CT images alone cannot distinguish a tumour from surrounding healthy tissue.

Lack of availability of PET/CT scanners, however, is a problem in many low- and middle-income countries. An added problem is that best-practice TVD contouring protocols and quality control may not be utilized consistently.

The International Atomic Energy Agency (IAEA) initiated a study to assess the impact of introducing FDG PET/CT-guided concurrent chemoradiotherapy, supported by training and quality control, on outcomes for patients with stage III non-small cell lung cancer (NSCLC). The study included nine medical centres in six middle-income countries – Brazil, India, Jordan, Pakistan, Turkey and Vietnam – and Estonia (a high-income country that does not routinely use PET/CT for radiotherapy planning). Newly reported interim findings reveal the benefits to patients, with improved overall and progression-free survival (Eur. J. Nucl. Med. Mol. Imaging 10.1007/s00259-019-04421-5).

The PERTAIN study, a part retrospective, part prospective study, aims to assess differences in two-year overall survival in patients receiving chemoradiotherapy with curative intent before and after a training intervention on the use of PET/CT for radiotherapy planning. The retrospective arm included 230 patients treated between January 2010 and July 2014, while the prospective cohort included 69 patients treated between August 2015 and October 2018.

Roughly half of the patients in the retrospective group were staged with PET/CT. The majority (86%) received 3D conformal radiotherapy (3DCT) and the remainder underwent intensity-modulated radiotherapy (IMRT). Eighteen patients only received radiotherapy, while the others underwent concurrent (64%) or sequential (28%) chemoradiotherapy. In the prospective cohort, all patients were treated with concurrent chemoradiotherapy, with 42% receiving IMRT, 3% treated with volumetric-modulated arc therapy and 55% with 3DCT.

Lead author Tom Konert of the Netherlands Cancer Institute and co-authors reported that interim findings showed much better outcomes for the prospectively-enrolled patients, even though they had more advanced NSCLC. Median progression-free survival in the prospective cohort was 17 months, significantly longer than the 11 months seen in the retrospective cohort. Overall survival was also increased in the prospective cohort, at 23 months, compared with 14 months for the retrospective cohort. Two-year overall survival was 47% in the prospective cohort and 27% in the retrospective cohort.

The nine medical centres in the study did not use PET/CT for radiotherapy planning. A radiation oncologist and nuclear medicine physician from each centre, neither of whom were experienced with PET/CT-based TVD in NSCLC, received intensive hands-on training in delineating the primary tumour based on IAEA-developed protocol guidelines. This training was supplemented by webinar sessions and lectures, in a train-the-trainers approach.

To ensure the use of current treatment standards, the entire radiotherapy planning procedure was standardized. Quality control was performed throughout the study, beginning with a detailed review of TVD of the first three patients from each centre.

While acknowledging that use of more precise radiotherapy delivery may have helped improve outcomes for the prospective group of patients, the researchers suggest that increased confidence in PET/CT-based contouring, and increased delineation accuracy may have improved tumour targeting for radiation dose delivery.

“The PERTAIN trial improved or reaffirmed collaborative working relationships between nuclear medicine and radiation oncology department in the participating centres,” the researchers wrote. “This collaboration may not only have led to improved delineation, but also may have improved patient management by streamlining the patient pathway from diagnosis to treatment.”

They concluded that a combined package of FDG PET/CT-planned radiotherapy, routine use of concurrent chemoradiotherapy with training support and a robust quality control process improved survival for patients with stage III NSCLC patients in low- and middle-income countries.

Peering into the past: using physics-based techniques to understand China’s history

Ghostly images slide across QiangBing Wei’s computer screen as he operates a mouse to move samples inside a scanning electron microscope (SEM). Wei, 25, is a PhD student at the Institute of Cultural Heritage and History of Science and Technology in Beijing. He’s using the SEM to magnify millimetre-sized pieces of ancient shard to several centimetres, making them look big enough so he can examine their microstructure. Peering over Wei’s shoulder, it looks like he is viewing a series of irregular islands with Google Earth.

The institute to which Wei belongs is part of the University of Science and Technology Beijing, one of the foremost universities for metallurgy in China. Wei’s mentor is Siran Liu, who received a PhD in archaeology from Imperial College, London, for a thesis on “Precious metal production and its social significance in Imperial China”. Liu has kindly offered to show me around the institute and describe the scientific instruments his team uses for their work on “metallurgical archaeology”.

Science and history

As we take the tour, Liu explains that better instruments for such studies are found at the Palace Museum – China’s huge national museum in the centre of Beijing. Scientists there even have dedicated beam time at the Shanghai synchrotron for analysing artefacts. But Liu says he and his colleagues are less interested in the final artefacts than in the technologies that produced them in the first place.

“The finished products, such as vessels, had to fit the cultural specifications and are very similar to each other,” Liu explains. “Analysing them gives you limited information about how they were made. I like the production remains – things like slag, and fragments of furnaces and crucibles. These preserve much information about the production process.” Such information, in turn, yields information about Chinese history that would otherwise be impossible to obtain.

Indeed, where there are few surviving historical documents – or even none at all – archaeology can provide virtually the only information about the period in question. To illustrate, Liu holds up a piece of ceramic. “This is from the Lithic period – the Stone Age – about 2000 BC,” he says. “We analyse these to see what techniques [people then] used and whether they traded with their neighbours, and learn about the economic activities of the era.”

In other instances, the institute’s work extends stories told by historians. Recently, for instance, Liu’s group studied lead-silver smelting during the Song dynasty (AD 960–1279). It was a period of huge demographic and technological changes, in which paper became widely used, printed books began to circulate, and China switched from an oral culture to one of the written word.

I like the production remains – things like slag, and fragments of furnaces and crucibles. These preserve much information about the production process

Siran Liu, University of Science and Technology Beijing

Among the technological developments in the Song dynasty was a big shift from furnaces to crucibles in the lead-silver smelting process in northern China. Another was a switch from using charcoal as a fuel to coal due to the impact of deforestation. But were these two changes related? And what impact, if any, did they have on other contemporary events? Research at the institute has discovered an intriguing link between them.

It turns out that early methods involved charcoal-fuelled furnaces placed in the centre of the ores. But the furnaces could not be loaded directly with coal, for coal softens as it heats up and then burns, which could cause the furnace to collapse. To use coal, the Chinese therefore needed to alter the smelting process, placing ore-containing crucibles inside the fuel rather than having the ore surround the furnace. This in turn meant it was better to locate smelting sites nearer the coal mines than the ore mines, for the necessary amount of coal was harder to transport, prompting demographic shifts as people moved closer to the smelting sites.

Archaeological metallurgy can also test historical narratives. Liu’s group, for example, is studying Chinese silver of the 17th century – the late Ming period. According to conventional historical accounts, China once had silver mines, but these eventually declined. When global trade developed in the 1600s, the story continues, products from thriving silver mines in South America, as well as Japan, began to inundate the European market. Taking advantage of the inexpensive silver, European travellers traded it in China for luxury items such as silk and porcelain.

“Is this story true?” Liu asks. “Well, we can find that out.” As he explains, the ores from different geological settings have different isotope ratios. The isotopic fingerprints of Chinese and South American silver are therefore different. Techniques such as lead-isotope analysis with induced coupled plasma mass spectrometry (ICP-MS) can be used to match these fingerprints in China’s silver, so that Liu’s team hopes to be able to answer the question definitively.

This year, members of Liu’s group, together with colleagues from Peking University, attended a summer smelting school in Hunan to hone their techniques. There they conducted experiments in ancient production methods, reconstructing ancient furnaces and firing them using traditional hand-powered bellows. “It’s exhausting,” Liu says. “You can do it for only 10 minutes at a time, and we have to take turns.”

The group then studies the effects of firing on their furnace materials, and compares them with archaeological samples of furnace materials. This work can reveal how ancient furnaces worked, the conditions under which artefacts were created, and what materials were fired. “All that information is trapped in this glassy remains,” says Liu, holding a small furnace fragment.

The critical point

As philosophers and historians have demonstrated, many technologies of the past several hundred years – for instance in agriculture, transportation, information and communication – have shaped human society and culture more significantly than battles and political victories. Liu and his colleagues are now using metallurgical tools to push such demonstrations back, not just hundreds but even thousands of years.

Atoms clocked at 5000 km/s as they race towards supermassive black holes

Observations of gas being sucked into the supermassive black holes at the centres of quasars have shed new light on how the astronomical objects convert gravitational energy into vast amounts of outgoing radiation. Hongyan Zhou at the Polar Research Institute of China and colleagues measured the speed of the infalling gas and confirmed that it was being supplied by “dusty tori” that surround quasars.

Quasars are so bright that they often outshine the galaxies they inhabit by several orders of magnitude. Lurking at the centre of a quasar is a supermassive black hole that can be millions or even billions of times more massive than the Sun. Vast amounts of radiation from the infrared to X-rays are emitted from a quasar and astrophysicists believe that this light is created by gas being accelerated violently in the accretion disc of matter that surrounds the black hole.

Astrophysicists are also pretty certain that quasars are sustained by a constant supply of gas that is fed into the accretion disc from a huge doughnut-shaped torus of interstellar dust that surrounds the black hole and accretion disc. However, it has proven difficult to verify this model because the vast amounts of radiation emitted by a quasar makes it very difficult to observe directly the gas as it flows from the torus to the accretion disc.

Doppler shift

To solve this problem, Zhou’s team postulated that any inflowing gas passing across our line of sight of the quasar should absorb some of the quasar’s light – and this would appear as a series of absorption lines in the quasar’s spectrum. By studying the pattern of the lines, the species of atoms responsible for the absorption can be identified. And crucially, the Doppler redshift of the wavelengths of the lines should reveal the velocity of the atoms.

The astronomers searched for two specific absorption lines — associated with hydrogen and helium – in the spectra of around 100,000 nearby quasars observed by the Sloan Digital Sky Survey. From these data, they identified eight quasars that displayed both lines simultaneously, allowing them to identify infalling gases with velocities ranging continuously from zero, to as fast as 5000 km/s.

Furthermore, the team discovered that the outer radii of the inflows corresponded to the inner radii of the dusty tori surrounding the black holes. Overall, this implied that inflowing gas is accelerated under the pull of the central black hole, to reach freefall speed just before it reaches the accretion disk; providing a reliable source of matter for the quasar.

According to the team, their study is the first unambiguous confirmation that quasar emissions fuelled by interstellar material trapped in the sphere of influence of supermassive black holes. Now, Zhou’s team now hope to differentiate between matter in the torus and in the accretion disk. This could potentially give astronomers a better understanding of how quasars form, how long they last, and how they end.

The study is described in Nature.

Can aquifer storage mitigate flooding?

In 2011 parched soils in Texas caused agricultural losses of around $8 billion in one of the worst droughts the state has ever seen. 2017 saw the opposite extreme when Hurricane Harvey dumped 150 cm of rain over south-eastern Texas in six days, resulting in extensive flooding, 68 fatalities and economic losses of over $100 billion. Whilst we can’t control the rain, we can control the water. A new study demonstrates the potential of the “managed aquifer recharge” technique for capturing flood water in Texas and injecting it into aquifers.

This technique, which already helps Texas manage its water supply, diverts floodwater, reducing its impact. It temporarily stores the water at the surface, before treating it and gradually injecting it into depleted aquifers beneath. This tops up groundwater supplies ready for the next drought.

To investigate this approach in Texas, Qian Yang and Bridget Scanlon from the University of Texas at Austin, quantified how much water could be captured and stored from the ten major rivers that discharge into the Gulf of Mexico.

Between 2015 and 2017 around 37 cubic km of water could have been captured from these ten rivers during high magnitude flow events, the scientists found. The excess water from these three wet years is equivalent to around twice the annual water demand in Texas in 2016 and would have been enough to replenish the depleted Texas Gulf Coast Aquifer system.

“Compared to traditional surface reservoirs such as lakes, depleted aquifers provide much greater storage capacity,” says Yang, whose findings are published in Environmental Research Letters (ERL).

By studying rainfall and river flow records over the last 50 years, Yang and Scanlon also show that small numbers of long duration events – longer than a week – contribute most to the large flow volumes.

Such schemes are more cost-effective than expanding surface water storage. Texas already has three operational managed aquifer recharge systems in place — at El Paso, Kerrville and San Antonio. Other parts of the world, particularly areas where aquifers have been depleted and flash floods are common, are also taking advantage of this way of balancing water supply and demand. To date there are over 1000 schemes in operation worldwide.

Climate change is projected to increase weather extremes, with floods and droughts anticipated to become more frequent and severe in many regions. Yang and Scanlon believe that managed aquifer recharge is likely to become a serious mitigation tool.

“I think managed aquifer recharge will become very prevalent in the future as a way of better managing water resources, especially in those regions that suffer from floods, droughts, and groundwater depletion,” says Yang.

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