Traditional paddy fields are flooded with a shallow layer of water for around 80% of the growing season. In response to rising demand for water, rice farmers have experimented with less water-thirsty methods in recent decades, including alternate wetting and drying, and mid-season drainage of the field. Short-term studies indicate that these methods can maintain yields. But whilst the new techniques save water, they may reduce soil fertility in the long run, according to a recent study.
John Livsey from Stockholm University in Sweden and colleagues conducted a meta-analysis to assess the effect of common water-saving techniques for rice agriculture on soil organic carbon and greenhouse gas emissions. They identified twelve studies that contained relevant data on soil carbon balance in both flooded and water-saving conditions. Analysing this data revealed that water-saving irrigation practices reduced methane emissions by over 50% and carbon-dioxide equivalent emissions by 18%.
At the same time the alternative irrigation techniques reduced soil organic carbon by 5% compared to traditional irrigation. That’s because soil moisture plays an important role in regulating soil organic carbon.
“In flooded conditions oxygen within the soil quickly becomes depleted and respiration switches from aerobic to anaerobic,” says Livsey, whose findings are published in Environmental Research Letters (ERL). “This results in a much slower breakdown of organic matter and accumulation of soil organic carbon.” Under drier conditions the faster breakdown of organic matter releases other nutrients, including nitrogen, that were chemically bound to the organic matter.
In the short term, the changes in soil organic carbon are negligible but over the longer term they may degrade soil fertility, potentially reducing yields and limiting future yield increases. Rice is a staple food for around half the world’s population.
Livsey and his colleagues suggest that water-saving practices receive tweaks to minimize their impact on soil fertility. “These could include restricting the extent to which soils are allowed to dry, or the number of times that fields are dried and re-flooded within a growing season,” he says.
What’s more it may be possible to mitigate impacts by leaving plant residues on the field after harvest or adding organic matter such as manure. For now though, the priority has to be more long-term data to understand the effects of water-saving practices better, with initiatives like the Sustainable Rice Platform playing a vital role.
The integrity of US government research is under siege and has been significantly weakened during the current administration of Donald Trump. That is according to a report by National Task Force on the Rule of Law and Democracy, which notes that recent presidential administrations have not only manipulated the findings of government scientists and researchers but also “retaliated against career researchers for political reasons”. It calls for Congressional legislation to protect the independence of government science data.
The report states that — along with manipulating findings and retaliations against scientists — US governments have also invited “outside special interests” to shape research priorities; “undermined and sidelined” advisory committees staffed by scientists; as well as suppressed research and analysis from public view – often material that had previously been made available. In many cases, the report adds, the administrations “have appeared to pay little political price for these missteps”.
We are at a crisis point, with almost weekly violations of previously respected safeguards
The task force, based at New York University’s Brennan Center for Justice, lists a number of issues that occurred under the two presidents who preceded Donald Trump. In the George W. Bush administration, for example, a politically appointed public-affairs officer prevented NASA climate scientist James Hansen from talking to the media in order, he said, to make the president look good. And political officials in the Obama administration’s Environmental Protection Agency (EPA) tried to downplay the risks to drinking water in a report on fracking, although scientists managed to reverse the decision.
‘Weekly violations’
Although previous presidents injected some politics into science, the report states that the Trump administration has tried both to politicize scientific and technical research on a range of topics and to undermine the value of objective facts themselves. “Now, we are at a crisis point,” the report declares, “with almost weekly violations of previously respected safeguards”.
Recent events, for example, include the “Sharpiegate” affair, in which the National Oceanic and Atmospheric Administration excoriated its weather forecasters for disagreeing with President Trump’s incorrect assertions about the path of Hurricane Dorian. The EPA also prevented academic researchers from serving on its scientific advisory boards in favour of industry-connected individuals. Another issue cited is the relocation of economists at the agriculture department from Washington after they revealed the harmful impact of the administration’s trade policies on farmers.
Writing in the Washington Post, panel members Christine Todd Whitman, who served as EPA administrator during George W Bush’s presidency, and former US attorney Preet Bharara note that Trump’s presidency “has exposed serious fissures in our system of government that require repair – especially when it comes to the integrity of government research”.
Infiltration of immune cells into melanoma. The images show tumour cells in blue and immune cells (CD8, CD4, natural killer and macrophages) in red, for control mice at day 5 (top row), mice treated with MRT at day 9 (middle row) and mice treated with conventional radiotherapy at day 9 (bottom row). (Courtesy: Int. J. Radiat. Oncol. Biol. Phys. 10.1016/j.ijrobp.2019.08.027)
Microbeam radiation therapy (MRT) uses synchrotron X-ray beams to deliver spatially fractionated radiation, with extremely high peak doses deposited in the microbeam path and tissue located between the microbeams receiving only a small fraction of this dose. MRT has proved highly effective in treating various tumours in small animals, while selectively sparing normal tissues. However, the mechanisms underlying the therapeutic efficiency of MRT are not well understood.
Malignant melanoma is one of the most aggressive cancers and is often radioresistant. “Although the main treatment for melanoma is surgery, in some cases resection is impossible due to the location of the tumour,” explains first author Marine Potez. “We wanted to find an alternative treatment for these tumours.”
With this aim, Potez and colleagues implanted radioresistant melanoma cells into the ears of mice. Roughly 10 days later, they divided the mice into three groups: 47 to be treated with MRT; 28 treated with conventional broad beam irradiation; and 26 non-irradiated controls. They performed all experiments using synchrotron X-rays produced at the European Synchrotron Radiation Facility.
The researchers treated the conventional group using a homogeneous 7.5×15 mm beam to deliver 6.2 Gy to the tumour. For the MRT treatments, the 7.5×15 mm irradiation field was covered by 37 quasi-parallel, 50-μm wide microbeams, with a peak dose of 407.6 Gy and a valley dose of 6.2 Gy.
Measuring tumour size before irradiation, on the day of treatment and then daily showed that both types of radiotherapy impeded melanoma growth compared with controls. Tumour volume doubled in 2.1 days in the control group, 3.7 days in the conventional group and 6 days in the MRT group. MRT significantly attenuated growth, with tumours shrinking from days 4 to 8 and then slowly growing again. Conventional irradiation, however, could not stop progression even temporarily, with tumours in this group exhibiting almost exponential growth throughout the study.
Irradiation set-up showing radiochromic film placed behind the irradiated ear. (Courtesy: Marine Potez)
Underlying mechanisms
To investigate why MRT offers better tumour control than conventional radiotherapy, the researchers first examined the impact of radiation on tumour blood vessels. They found that MRT altered blood vessel integrity and significantly reduced blood perfusion into irradiated tumours. At day 5 after irradiation, for example, 68.5% of vessels in the MRT group were perfused, compared with 86.3% and 81.5% for conventional and control groups, respectively.
Irradiated tumours also exhibited a reduced tumour cell proliferation index compared with controls, from day 2 in the MRT group and day 5 in the conventional group. MRT resulted in lower proliferation rates, with maximum divergence on day 9 when the proliferation indices were 14.5% and 70.9%, for MRT and conventionally treated tumours, respectively.
Immunostaining excised tumour slices for senescence – in which cells no longer divide but are still metabolically active – revealed a marked increase in senescence after MRT from days 2 to 9, compared with the other groups of mice.
This MRT-induced senescence significantly enhances the production of chemokines involved in recruitment of monocytes (a white blood cell involved in immune processes) in tumour tissue, which the team confirmed using Bio-Plex immunoassays. This led to a massive influx of immune cells (macrophages, natural killer cells, CD4+ and CD8+ T lymphocytes) in MRT-treated tumours from day 5 to day 12, which can induce inflammatory and anti-tumour immune responses.
“We observed that the first tumour response after MRT was vascular damages and senescence,” says Potez. “We hypothesized that the high influx of immune cells, recruited by the senescence-associated secretory factors, caused the vasculature impairments.”
The researchers suggest that MRT represents a promising candidate for new clinical trials to explore the clinical relevance of these anti-tumour effects. Currently, however, MRT is in the pre-clinical stage, including trials on pets with spontaneous tumours and on pigs, which provide a good intermediary between small lab animals and human patients.
Potez notes that due to the particular irradiation geometry of MRT, positioning and treatment planning are still under development for patients. “Also, MRT can only be performed at third-generation synchrotrons to fulfil the requested parameters, such as the dose rate and parallel-non divergent microbeams,” she says. “To be more accessible for patients, the development of compact sources is ongoing.”
In the next stage of this project, the researchers are characterizing the infiltrating immune cells. “We are also testing different treatment protocols with multiple irradiations and ports, and we are combining MRT with nanoparticle injection,” Potez tells Physics World.
Gaining a degree in physics is no mean feat. As a student, you’re busy completing lots of assignments in many different modules, and tackling experiments in the lab too. So it isn’t surprising that, for most students, extracurricular activities often fall into a black hole of “things you don’t have time for”. However, having a rich life outside your core academic activities is vital when it comes to helping you figure out what you want to do after you graduate, and getting the right job.
While good grades are important, students also need a broad range of transferable skills. This includes learning prioritization, communication, teamwork and problem solving; taking initiative, showing resilience and leadership; and developing business acumen and skills such as negotiation and persuasion. The need for transferable skills isn’t limited to jobs in industry – you’ll need these skills even if you want to build an academic career.
Indeed, in my experience of working with companies that hire physicists, the most employable graduates are those who engage in extracurricular activities. By doing so, students are exposed to new and challenging environments, which builds their confidence, and often leads to further opportunities.
Such extracurricular activities includes not only part-time jobs, summer placements and internships, but also everything from coaching, tutoring and managing your physics society to sitting on a committee, contributing to a special interest group, organizing events or volunteering. By participating in these activities, you are, consciously or unconsciously, preparing yourself for the next stage in your life, wherever this takes you.
Taking up a placement or internship, especially in a field or company that you may want to work for, is a particularly good idea. There are many ways to go about this. While you can find a placement or internship under your own steam, there are many resources in place to help. For a start, speak to your careers adviser or tutor, who can point you in the right direction. The Institute of Physics (IOP) also offers a number of opportunities to help you gain experience and develop those all-important transferable skills (see box below). A handful of graduate training programmes have even been officially accredited by the IOP, all of which combine dedicated events, training modules, professional development, mentoring and on-the-job experience.
The IOP currently works with 21 companies, from Atkins and Leonardo to EDF and Sellafield, which deliver graduate training programmes for physics students, through the Accreditation of Company Training Schemes (ACTS). Accreditation indicates that the training scheme has the appropriate criteria for physicists working towards gaining professional registered status.
The message is clear – transferable skills are essential. But instead of trying to convince you any further myself, here are some case studies of physics graduates who have taken up a host of placement and volunteering activities.
Molly Burkmar.
Molly Burkmar
I’m currently studying for an MPhys in physics, astrophysics and cosmology at the University of Portsmouth, UK.
During my second year I decided to apply for South East Physics Network (SEPnet) placements, after learning about the organization at a careers day at university. SEPnet links university physics departments in south-east England and organizes summer placements for physics undergraduates and PhD students to develop their employability skills and raise awareness of their career options in business and industry. I looked through the profiles of more than 60 placements and applied for five, but it was the placement at Winchester Science Centre that caught my eye, as I’m thinking about going into teaching. Thankfully, the interview went really well and I was offered the job. I was really nervous to start with as this was my first job in the science industry, but the team was very welcoming, and I got settled in quickly.
My placement at Winchester was split into two parts: being an “inspirer” and evaluating an exhibit. Most of my time was spent on the former, which involved science busking, floor walking around the exhibits and presenting the live science show. My project involved evaluating a display known as “Stem Cell Mountain” and recommending how to improve it.
My confidence has increased from presenting shows. I was nervous about doing them to begin with, but I started by teaming up with another member of staff to deliver them and presented my first solo show in front of the head of the planetarium. This was really helpful to gain confidence and get constructive feedback before doing them solo and it became my favourite part of the job. I have gained so much experience being an educator too. I picked up tips on how others presented and taught around the centre, which helped me to successfully communicate to a wide range of ages and science backgrounds. Seeing children learning and getting excited about science has been the most rewarding part of the job.
I used skills from my laboratory module at university during the project, such as keeping a lab notebook, but I’ve also learnt a lot about evaluation. I’ve taken observations, semi-structured interviews and surveys as well as analysed both quantitative and qualitative data. I then used the data to make small modifications to the exhibit to see if they were successful so I could make recommendations on how to improve it. My study was one section of a bigger project to modify Stem Cell Mountain, but it was really interesting to see the evaluation side from start to finish.
By undertaking a placement, I’ve gained so much experience that I can use to help me with the rest of my degree and when applying for jobs. I would really recommend completing a placement in an area you’re interested in as there are a lot of job-specific skills that can’t be taught at university.
Adam Powell.
Adam Powell
I am a graduate student with the University of Calgary, Canada, as a member of the Antihydrogen Laser Physics Apparatus (ALPHA) collaboration at CERN.
During the foundation year of my physics degree at Swansea University, UK, when the opportunity to lead the university’s physics society arose, I leapt at the chance. I had begun my degree at a disadvantage, not having taken maths past the age of 16, so I was all the more motivated to find my place. A few months after taking on the society, I had helped to organize the first in a number of careers events to help my peers (and myself) see the vast number of possible pathways through physics. This was also my first interaction with IOP Wales, and my first outreach event came soon after – eventually I became a campus ambassador and nations committee member.
As my network started to grow, I was offered an internship with the university’s employability academy. I spent a summer focusing on the softer skills that are incredibly important in an increasingly competitive workplace. I was encouraged to apply for the Undergraduate of the Year awards sponsored by Target Job and was shortlisted in the men’s category. The reward for this was an interview at L’Orèal UKI. I was aware of the brand but had no experience in the beauty industry. Determined to show what I could do for them, I took the sample data provided and set to work on analysis. After combining skills learnt through my studies with some impromptu market research (questioning the unfortunate travellers on a Swansea to London train about the various products) I was offered a summer placement in the business development team. While my time with L’Orèal was full of very valuable learning experiences and wonderful people, it wasn’t for me long-term. I learnt the most valuable lesson of all – that it is just as useful to know what you don’t want to do, as what you actually want to do.
I returned for my final year at Swansea, now as an MPhys student, with a desire to focus on research. I was then incredibly fortunate to be sent to CERN to carry out my final-year project with the ALPHA experiment. I spent three months working in an environment that pushed me every day, and I was hooked. Knowing that I wanted to return after my MPhys, I set about trying to find a postgraduate position. A few discussions later, I was hired as a research assistant by the TRIUMF laboratory in Vancouver to help in the construction of the new ALPHA-g experiment at CERN. This then led to my current place as a graduate student with the University of Calgary as a member of the ALPHA collaboration and I currently hold a Leverhulme Trust Study Abroad Studentship.
Despite now being based outside Wales, I’m still a regular volunteer and committee member, and played a role in organizing the IOP-sponsored Conference of Astronomy and Physics Students 2019 at Swansea.
After the first year of my Master’s degree, I was looking for opportunities to gain some experience working in professional labs, which I saw as necessary for my career plan. I found many of the adverts on GRADnet interesting, but was particularly keen on working at the National Physical Laboratory, because most companies advertised for data science internships, whereas NPL’s placement was focused on experimental physics.
I worked on a project to build a method to reconstruct the spectrum of a 2D material using photoluminescence imaging techniques. This involved using the LabView platform, which is an indispensable tool in experimental physics. I also worked in an optics lab where I learnt not only how to work with several instruments, but also how to approach a new and unfamiliar instrument. While it was a struggle to transfer my bookish knowledge to real-life experiments, I learnt what experimental physics actually entails.
The placement helped me sharpen both my technical and professional skills. The standard of professionalism expected of a student is not that expected in a real working environment and I learnt a lot by just watching my superiors and peers every day. Indeed, I believe this placement was one of the most important learning experiences of my career so far, and will help me work on future projects more efficiently.
I also made many friends who were mostly PhD students. From them, I was able to get a great insight into how the organization worked and all its activities. They were then able to give me advice about what they would have done differently before starting their PhD.
The placement was an invaluable learning experience. I would highly recommend anyone who has the chance to take up a summer placement with SEPnet, GRADnet or the IOP, and to utilize it to its fullest.
During the second year of my MPhys degree in physics at the University of Surrey, UK, I began to think more seriously about what I wanted to do after I graduated. Pursuing a career in research had always interested me, so I figured that a research-orientated placement would be the perfect opportunity to discover first-hand what it is like to work in a research environment. This led to me applying for an eight-week SEPnet summer placement at the National Physical Laboratory in Teddington. There, my role was to evaluate a phenomenon known as “non-uniqueness”, associated with standard platinum resistance thermometers used to realize the International Temperature Scale of 1990.
Non-uniqueness is a very subtle form of uncertainty associated with temperature measurement that, as a result of the ever-improving precision to which we can perform temperature measurements today, is becoming a fundamental limiting factor in the accuracy we are able to achieve. My task during the placement was to try to quantify the uncertainty associated with this non-uniqueness in the thermometers. The first half of the placement was spent performing measurements in the lab, where I determined the resistance ratios of the thermometers in temperature-controlled oil baths, liquid nitrogen and fixed-point cells, over a range from –196 °C to 232 °C. I then plotted and analysed the data collected in order to gain a clearer picture of how non-uniqueness affects our most accurate temperature measurements.
This was my first experience of not only collecting high-quality experimental data but also of performing careful data analysis, both of which are absolutely invaluable skills for a career in research. Conducting research during my placement was a very different experience to studying at university, as many of the questions we were asking didn’t have a known answer. This aspect of exploring the unknown is something I found really exciting and it led to me developing a wide range of useful skills, from critical thinking to problem solving.
Working at NPL definitely confirmed my desire to work in a research environment and showed me the wide variety of opportunities available. I was constantly asking the staff at NPL about their research and everyone was very happy to share their work with me, so I got to learn a lot about metrology/traceability of measurement and its importance in every aspect of our lives.
For any undergraduate interested in expanding their skill set and experiencing the real-world implications of what they are taught in lectures I would highly recommend carrying out a placement. Not only does it look great on your CV, it also provides some invaluable tools for a potential career in research in the future. Don’t be put off applying if you don’t have a lot of direct knowledge about the placement subject area, as plenty of help and support are provided. I knew nothing about the world of metrology before my placement, but I found the scheme to be a fantastic opportunity to extend my knowledge of a given area.
How the IOP can help you
The Institute of Physics (IOP) is here to support you in building a successful career through our programme of activities. Members of the IOP can:
Become a part of the IOP student community and participate in a host of activities to develop skills: iop.org/student-community
Volunteer for IOP-led physics engagement activities to practice your communication, organizational and teamwork skills: iop.org/volunteer
Plan and organize scientific meetings, working in collaboration with other IOP groups and sister societies. Promote events through your institutions and networks, and coordinate and generate digital content for your chosen group(s): iop.org/groups
Gain an advantage in the job market by attending our employer-led careers events and participate in career-themed webinars. You can also participate in events and conferences, at exclusive member discounted rates, to keep up to date and network with peers and experts in academia and industry: iop.org/events
Make use of the IOP careers hub, which will support you in writing your CV, practising for interviews, delivering presentations, and effective time management, among many other useful resources to support your future career choices: iop.org/member-services
Take advantage of our international travel grants to attend conferences, such as the Research Student Conference Fund, the C R Barber Trust and Early Career Researchers Fund: iop.org/grants
Following graduation, join the Member grade and use the designatory letters MInstP after your name, to demonstrate your commitment and professionalism: iop.org/member
A new refrigeration technology based on the twisting and untwisting of fibres has been demonstrated by a team led by Zunfeng Liu at Nankai University in China and Ray Baughman at the University of Texas at Dallas in the US. As the demand for refrigeration expands worldwide, their work could lead to the development of new cooling systems that do not employ gases that are harmful to the environment.
The cooling system relies on the fact that some materials undergo significant changes in entropy when deformed. As far back as 1805 – when the concepts of thermodynamics were first being developed – it was known that ordinary rubber heats up when stretched and cools down when relaxed. In principle, such mechanocaloric materials could be used in place of the gases that change entropy when compressed and expanded in commercial refrigeration systems. Replacing gas-based systems is an important environmental goal because gaseous refrigerants tend to degrade the ozone layer and are powerful greenhouse gases.
In their experiments, Liu and Baughman’s team studied the cooling effects of twist and stretch changes in twisted, coiled and supercoiled fibres of natural rubber, nickel-titanium and polyethylene fishing line. In each material, they observed a surface cooling as high as 16.4 °C, 20.8 °C, and 5.1 °C respectively, which they achieved through techniques including simultaneous releases of twisting and stretching, and unravelling bundles of multiple wires.
Supercoiled fibres
The team also made supercoiled fibres of natural rubber in which the twisting and coiling were done in opposite senses (clockwise and anticlockwise). Much to their surprise, they found that these structures cooled when stretched, rather than heated.
The team also looked at microscopic changes in the materials. An X-ray diffraction crystallography study of the polyethylene fishing line revealed changes in molecular structures associated with the transition from low to high entropy phases. The team identified this process as the cause of the effect, which they have dubbed “twistocaloric” cooling.
Liu, Baughman and their colleagues then built a simple device from a three-ply nickel-titanium wire cable, which cooled a stream of running water by as much as 7.7 °C as it unravelled. They propose that far higher levels of cooling could be reached through additional cycles of twisting and twist release within the cable — resulting in a highly efficient fridge.
The team faces many challenges in creating commercially-viable twist fridges, including the need find a material that is not degraded by being repeatedly twisted and untwisted. So far, they have only explored few commercially-available materials, but now plan to expand their research to seek-out materials that have optimized mechanical and twistocaloric properties. If realized on commercial scales, twist fridge technologies could provide climate-friendly solutions to meeting our rapidly expanding demand for cooling.
Each of the five mass extinctions over the last 500 million years that saw at least 75% of species disappear was accompanied by a surge in carbon entering the ocean. But carbon pulses are relatively common and usually benign; there were around 30 over that same time period. So what sets mass extinction events apart?
A study suggests that Earth’s oceans have a distinct threshold when it comes to the amount of carbon they can process. Mass extinction events occur when the threshold is passed. Anthropogenic carbon dioxide emissions are comparable to the carbon surges associated with previous mass extinction events, suggesting that we’re likely to be triggering a sixth mass extinction event right now.
Carbon is constantly cycled around our planet. Photosynthesis converts carbon dioxide to organic carbon; respiration converts organic carbon back to carbon dioxide. Sometimes carbon ends up in a long-term store, for example when small ocean creatures such as coccolithophores sink to the sea-floor and lock the carbon into sediments, but eventually the carbon returns to the loop as, in this case, geological processes uplift the rocks and weathering releases the carbon to the atmosphere.
Many external triggers can disrupt the carbon cycle including variations in orbital motions, release of methane hydrates, meteorite strikes, evolutionary changes and volcanic emissions. Ocean sediments record those disruptions, with carbon-rich rocks forming when atmospheric carbon dioxide levels are high. Until now, the consensus has been that the ocean responds proportionately to the amount of carbon being pumped into it: the larger the trigger, the more carbon-rich the ocean sediments become.
However, Daniel Rothman from Massachusetts Institute of Technology, US, was puzzled by the fact that, regardless of their size, most carbon pulses result in a characteristic rate of change in the ocean’s store of carbon but mass extinction events appear to have a far greater rate of change. To understand this anomaly, Rothman modelled the marine carbon cycle mathematically, exploring how disruptions to the incoming carbon flux were likely to influence the way that carbon was stored.
The model demonstrated that up to a certain limit, Earth’s oceans can absorb and process pulses of carbon dioxide and return to their steady state. But above a certain threshold, the oceans were pushed out of their steady state, resulting in acidification at the surface.
“I’m suggesting that the magnitude of the disruption is determined not by the strength of the external stressors but rather by the carbon cycle’s intrinsic dynamics,” says Rothman, whose findings are published in the Proceedings of the National Academy of Sciences (PNAS). His results suggest that this ocean threshold is yet another “tipping point”, beyond which there’s a nonlinear response.
By looking at the size and duration of the 31 disruptions to the global carbon cycle over the last 542 million years, Rothman showed that the majority have a characteristic rate of change, but that four of the five mass extinction events grew faster than this.
The model suggests that the ocean threshold also depends on the duration over which the carbon flux is increased. Relatively weak but long-lived perturbations, such as massive volcanic eruptions occurring over millions of years, can overshoot the threshold. But short sharp disruptions, like the intense pulse of carbon dioxide produced by current anthropogenic emissions, can pass the threshold too.
Rothman shows that today’s anthropogenic emissions and the carbon dioxide associated with massive volcanism in the past are roughly equivalent in their potential to pass the ocean threshold. This suggests that mankind’s actions may well trigger a mass extinction event. But because the oceans take a while to respond, it will be some time before the sixth mass extinction event becomes visible in the rock record.
“If the carbon cycle passes the threshold, the effects would play out over a period of ten thousand years or more,” says Rothman.
Map of tumour elasticity (in kPa) showing the marked stiffness of pancreatic tumours in a mouse model. (Courtesy: Yann Jamin/ICR)
Researchers from the Institute of Cancer Research (ICR) have used MR elastography to visualize and measure the stiffness and density of tumour tissues in mice. The non-invasive imaging technique provides crucial new information about cancer architecture and could help deliver treatment to challenging tumours (Cancer Research 10.1158/0008-5472.CAN-19-1595).
Tumours are formed from dense and compact networks of cells, structural fibres and blood vessels. Some tumour types are particularly stiff and dense, which makes it difficult to deliver drugs deep inside the tumour mass and hinders treatment. Tissue stiffening is also associated with tumour progression and metastasis. The major contributor to this increased stiffness is collagen – a key component of bone, cartilage, tendons and the extracellular matrix that holds tissues together.
Drugs designed to break down the extracellular matrix, such as collagenase, can weaken the structure that holds a tumour together and allow other cancer drugs to reach cells in its centre. Assessing the contribution of collagen to relative stiffness could identify tumours with the potential to be treated by with such drugs.
The ICR researchers, working in collaboration with King’s College London, combined MR elastography with computational histopathology to investigate the contribution of collagen to the biomechanics of several different tumour types in mice. They found, for example, that breast tumours were around twice as stiff as brain tumours and around three times as dense.
The pre-clinical study demonstrated that increased collagen correlated with elevated tumour elasticity and viscosity, with collagen key to keeping breast and pancreatic cancers stiff and inaccessible to treatments. In contrast, tumours arising from the nervous system, such as some forms of childhood cancer and brain tumours, were relatively soft and lacking in collagen.
“Our research shows that this new type of scan can give valuable diagnostic information about breast and pancreatic tumours non-invasively by assessing their stiffness,” explains study co-leader Simon Robinson. “If confirmed in a clinical trial, we could use this technique to identify patients most likely to benefit from treatments that target the dense scaffold upon which these tumours grow.”
The researchers also used MR elastography to monitor the weakening of tumour structure following treatment with collagenase. They found that collagenase resulted in a clear reduction in the elasticity and viscosity of breast tumours in mice – both of which fell by around a fifth. This finding suggests that the technique, which can be performed on a conventional clinical MRI scanner, could help identify the optimum time at which to deliver chemotherapeutic drugs by showing when the tumour is most vulnerable.
“There’s a lot of research activity centred on finding new therapies designed to help anti-cancer drugs reach their target in breast and pancreatic cancers, which can be so stiff and dense that they are impenetrable,” says study co-leader Yann Jamin. “We are very excited to have found a rapid scan that can be incorporated into a current routine clinical MRI examination and can potentially monitor the effects of these new tumour-weakening therapies, and assist the development and delivery of medicines which could save or extend lives.”
A new Masters programme in nanoscience and nanotechnology has been specifically designed to give students the skills and experience they need to work in the fast-moving nanotechnology industry. The course, which was launched in September 2018 by the University of Central Lancashire (UCLan) in the UK, builds on the university’s strong reputation for nanotechnology research, as well as its established links with industrial partners in the UK and beyond.
According to Dr Joe Smerdon, the course leader, the hope is “to convert some of these MSc candidates directly into employees”. One notable feature of the course is an optional one-year industrial placement, and even the more conventional taught elements of the course will enable students to interact with companies developing commercial applications for nanotechnology.
“We wanted to make the course very relevant to employers,” says Smerdon. “We will be bringing in industrial partners to talk about nanotechnology and their current challenges, and then incorporate that insight into the teaching programme.”
They can work within our areas of research, complete an industrial placement, and then potentially be offered a suitable position with the industrial partner
Dr Tapas Sen, UCLan
Smerdon explains that prospective employers will be able to engage directly with the students from the beginning of the second semester all the way through to the end of the course. “There’s one module that allows students to directly participate in a challenging problem posed to them by the industrial partners, and the partners have the option of assessing their work if they want to – both at the proposal stage and the final project stage.”
The hope is that such direct interaction early in the course could pave the way for a final-year project working with the partner, or an industrial placement that would enable the student to really understand what it’s really like to work for the company. “The students have the option of doing a full year’s placement with a partner: they do the first two semesters at UCLan, spend a year with an industrial partner, and then return for the third semester,” explains Smerdon.
Prospective employers also have the opportunity to get to know the students they are working with. “They can indicate whether they are interested in working with particular students for their placement year or final-year project,” he says. “It’s very hard to select an engineer or a scientist based on an interview or presentation, and this way they get up to a year to find the right candidate.”
The extra industrial year could be particularly appealing for international students, since a one-year MSc is generally not recognized outside the UK. But according to Dr Tapas Sen, one of the other post-graduate course leaders, the real attraction for overseas students will be the potential to find a job with a local company. “They can work within our areas of research, complete an industrial placement, and then potentially be offered a suitable position with the industrial partner,” he says.
Hub for industrial research
And it’s not just the industrial connections that students will benefit from. UCLan is developing a centre for nanotechnology research, with several of the course tutors, including Smerdon, recently completing five-year research fellowships at the university. “We’re all high-performing researchers in nanotechnology, and we have built the course around this core expertise,” he says.
Launching the course is also part of a wider aim to establish UCLan as a hub for industrial nanoscience. Another major initiative, overseen by Sen, has been to establish a Society for Functional Nanomaterials to enable two-way communication between academia and industry. “One of the main reasons for slow development of nanoscience in real-life applications is a lack of understanding and collaboration between industry and academia,” he comments.
And both Smerdon and Sen are confident that nanotechnology will be a major driver for future innovation in the commercial sector. “We’re seeing a few things now, such as quantum-dot televisions that deliver better colour rendition, but there’s a whole more just around the corner,” says Smerdon. “We’re still not really exploiting the inherent benefits of nanosized materials and structures, and when we do nanotechnology will become increasingly ubiquitous.”
Smerdon is confident that the course offers a natural progression for students who have completed an undergraduate degree in the physical sciences. Michael Holmes, who embarked on the course after finishing an undergraduate degree in astrophysics, agrees: “My experience during this degree has been very positive,” he says. “I was worried about adapting to nanoscale science, but continued communication and support from all staff made it a very smooth transition.”
A core module in nanoscience and nanotechnology runs throughout the course, offering a multidisciplinary approach that spans physics, chemistry and the biosciences. Students can also choose optional modules in physics and chemistry that are pitched at different levels based on their existing knowledge. “The course offers a good balance of taught and self-taught modules,” says Holmes. “For example, the taught Advanced Nanophysics module was a great complement to the Current Topics in Industrial Nanoscience module, which involved a lot of individual research.”
Some of the modules are taught in the traditional way, through lectures, seminars and tutorials, and Smerdon says that compared to an undergraduate degree there’s not a great deal of difference in terms of teaching time and the level of support students receive from the lecturers. But students have more opportunities for self-directed research, and also have the freedom to pursue their own interests – whether that’s in industry or academia.
“I really enjoyed the freedom to use the most modern and advanced techniques,” agrees Holmes. “It felt very satisfying and fulfilling, especially compared to undergraduate work.”
The minimum entry requirements for UCLAn’s MSc in Nanoscience and Nanotechnology is a 2:2 in physics, chemistry, or a related subject, plus international students must meet a minimum language requirement (International English Language Test (IELTS) with an overall score of 6.5 and no element should be less than 6). Applications are open year round, for entry in September, and most students can apply for funding through a Postgraduate Master’s Loan.
A third of adults are consistently not getting enough exercise, reported the World Health Organisation in a 2018 study. In addition, obesity has been claimed to be a national emergency in the UK.
The use of consumer based health and wellness trackers such as smart watches or smart clothing has the potential to increase physical activity participation. Many of these devices noninvasively track vital health signs by optical detection. However, this technology is limited by the need for rigid materials. To overcome this, Emre Polatet al. have developed a new class of flexible and transparent wearables based on graphene sensitized with semiconducting quantum dots.
The new technology can successfully measure heart rate and oxygen saturation. It also has the potential to measure blood pressure and cardiac output, whilst maintaining its flexible and transparent form. The group has used the approach to develop a plethora of prototype fitness trackers such as a heart-rate monitoring bracelet and a wireless ultraviolet (UV) monitoring patch, which informs the user of their current UV exposure and recommended remaining exposure time via a mobile phone app.
Emre Ozan Polat (first author of the study), Marc Montagut , Stijn Goossens, Shuchi Gupta, Frank Koppens (leading author of the study), Gabriel Mercier, and Turgut Durduran. Shuchi is holding the wireless UV monitoring patch. Credit: ICFO
Monitoring heart rate
Health and wellness trackers based on optical absorption can operate in two modes. The flexible heart-rate bracelet operated using reflectance mode. Here, an integrated green LED is shone through the skin and onto the user’s blood vessels. The cardiac cycle changes the volume of the vessels, which modulates how much light is reflected back towards the photodetector. In this way, the heart rate can be reliably and accurately extracted from the user’s wrist. Transmission mode is used to operate the mobile phone integrated health patch in a similar way. However, instead of using an LED, the patch uses ambient light passing through the thumb tissue to measure the changes in cardiac cycle.
Discrete fitness trackers
Whilst health and wellness trackers based on optical detection have been on the market for some time, conformable sensors that are aesthetically pleasing have, until now, been next to non-existent. By using graphene in their new devices, Polat’s team have managed to develop fitness trackers that are transparent and flexible, allowing for the development of a range of discrete fitness trackers. In addition, these low-cost devices have the potential for wireless charging, and offer other benefits key for this type of detector such as broadband wavelength sensitivity. This extends the number of vital signs that can be measured.
Physicists are known to have an occasional flutter – especially when it comes to the possible discovery of new physics. Avid readers may remember in 2000 when 20 physicists, including theorist Nima Arkani-Hamed, bet that supersymmetry would be experimentally detected within 10 years. They ended up losing and apparently had to dig deep in their pockets to buy a bottle of “good cognac at a price not less than $100” for the 24 physicists who won the bet.
Now, its physicist Michio Kaku’s turn to get the chequebook out. In 2002, the US science writer John Horgan had a $2000 bet with Kaku that by 2020 “no one will have won a Nobel Prize for work on superstring theory, membrane theory, or some other unified theory describing all the forces of nature”. Now that the 2019 prize has been awarded to pioneering work in cosmology and the detection of the first exoplanet, there can be no grand unified theory Nobel prize this decade. Given that Horgan’s loot will be donated to the environmental non-profit group Nature Conservancy, at least it’s all for a good cause.
While urban areas can often be hotter than the surrounding countryside, at least you can shelter in the shade of tall buildings to beat the heat. Now, Xiaojiang Li and an international team of colleagues have created a routing algorithm that minimizes a pedestrian’s exposure to direct sunlight while walking through central Tokyo.
The team used Google Street View panoramas of Tokyo’s skyscrapers to work-out how much sunlight filters down to street level. Combining this with the position of the Sun, the algorithm was able to reduce exposure by an average of about 35% on 1000 random routes through the city. Li and colleagues point out that the same system could create routes with maximum sunlight exposure in the winter.
Just about everyone loves a deep-fried potato snack, but did you ever wonder how they get so puffy? In “Predicting lift-off time when deep-frying potato dough snacks”, Thomas Babb and colleagues model how a dense lump of dough is transformed into a foamy bite when plunged into hot oil. According to the abstract of their preprint, “the model simplifies to solving a one-dimensional Stefan problem in the snack”.
And if that has whet your appetite, tuck into this article about how the physics involved in making potato crisps (or chips).
