I,Science Issue 37 (Summer 2017)

I, SCIENCE THE SCIENCE MAGAZINE OF IMPERIAL COLLEGE

elements summer 2017

issue 37

INSPIRE

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Become a newly qualified teacher (NQT) in just 10 months and join a network of colleagues who will help shape the future of STEM education.

Places are now available for applicants who have, or will have, a Master’s or PhD degree in Physical Sciences, Maths or Engineering by August 2017. » Get hands-on teacher training in London-based secondary schools. » Receive a tax-free government bursary of up to £30,000* plus a £2,000 bursary from Imperial College London. » Work alongside Imperial researchers on bespoke activities to inspire the future generation of chemists, engineers, mathematicians and physicists.

WANT MORE INFORMATION? Informal information sessions run throughout the year. These are a chance to: » talk to the programme co-ordinators. » see the work of current INSPIRE students.

Email INSPIRE@imperial.ac.uk for details and to book your place.

For more information:

www.imperial.ac.uk/inspire * The Department for Education provides bursaries for trainee teachers from the UK/EU. For eligibility details for your subject see: https://getintoteaching.education.gov.uk/funding-and-salary/overview

Teacher training with a difference Up to £32k in funding Bespoke science communication masterclasses Engage with pupils in over 10 schools

I,SCIENCE THE SCIENCE MAGAZINE OF IMPERIAL COLLEGE

Editors-in-Chief Bruno martin Madeleine Finlay Magazine Editor raquel Taylor Web Editor Lucy Timms Pictures Editor Natasha gertler Business Manager liz killen Marketing and social Media Tori Blakeman Radio Editor catherine Webb News Manager Sarah Barfield Marks Online Features Manager katharina kropshofer Events Manager judit agui TV Editor Vidish Athavale Sub-Editors Ipsita Herlekar Frances McStea Marcela Leite Helena Spooner rachel baxter emma lisle david walker Cover Illustrator Alexander James Interested in advertising with us?

Contact : iscience-business@imperial.ac.uk I, Science, c/o Liam Watson, Level 3, Sherfield Building, Imperial College London, London SW7 2AZ Email: i.science@imperial.ac.uk Printed by:Leaflet Frog, 38 Britannia Way, Bolton BL2 2HH

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I,SCIENCE S

cience is a human activity, like art or history. There can be no science without someone who is curious, someone to experiment, someone to draw conclusions. But, more than that, science is a social enterprise— people do science together. When we do things together, we trade skills, time, resources and opinions. We may even argue. Despite its claim to objectivity, science, like all social activities, is subject to the humanity of people. For many, it may seem that we should distill science right back to its core: the true, non-negotiable facts. Yet, even these are dreamed up in strange moments, discussed in dark corners of journal offices and much later reformed by new thinkers with modern theories. So perhaps it is not desirable, or even possible, to strip science from its murky social clothes and leave it bare.

Even the basics are infused with culture and humanity.

With this in mind, in our last magazine of the academic year, we’ve stripped back the layers until we hit the building blocks of matter: the elements. They are our most direct and tangible grasp on nature, but that doesn’t make their stories simple.

We’ll be discussing the pasts, futures, politics and people of the elements of the periodic table. Each one has a tale to tell—in this issue, we explore just what the fundamental ingredients of nature are really made of.

Or perhaps not! On pages 6 and 7 Peter Fox explores the possibility of life made not from carbon, but silicon. If that seems a little far-fetched, turn to pages 8 and 9, where Tori Blakeman and Amy Thomas investigate the madness in mercury and the lunacy in lead, both of which could kill you. And they aren’t our only deadly elements; on page 30 Catherine Webb looks at why we’ve put potassium in the lethal injection, and on pages 24 and 25 Chun Yin-San explains how tantalum has been a fuel for war in Democratic Republic of Congo.

If you’re interested to find out more about what we’re doing with the elements, Jennifer Hack reviews the use of lithium in batteries, on page 13, and on page 12 Jonathan Bosch discusses developing hydrogen as a sustainable energy source.

We’ve also been looking at how people get their own body’s power supply: turn to page 23 for Samantha Oon’s take on carbon as food.

Finally, if you fancy assessing your knowledge, head to page 31, where you’ll find a test paper from the dusty shelves of our archives: Imperial’s own chemistry matriculation exam, from 1917. We wish you good luck, and hope that it is your very last quiz for the year. bruno and madeleine

I, Science is a publication of the Science Communication Unit, Centre for Languages, Culture and Communication, Imperial College London. However, it is a student publication, and as such the views expressed in I, Science do not reflect the views of the Unit, Centre or College.

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Find more great content on our website: www.isciencemag.co.uk

We’re always on the lookout for new contributors for both the magazine and the website.

If you would like to get involved as a writer, editor or illustrator please don’t hesitate to get in contact. You can email us at i.science@imperial.ac.uk, tweet us @i_ science_mag or contact us directly through our website www.isciencemag.co.uk.

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Contents News

|

5

6

| Silicon

Could silicon be a basis for a new, alternative life form?

Mercury |

8

You’ll be as mad-as-a-hatter with mercury.

Helium and Phosphorous | 10

Two of our vital resources are being frittered away, and soon will be much harder to come by.

Lithium | 13

From phones to cars, lithium batteries power the 21st century.

Americium | 15 Is there a place for patriotism in science?

Iron | 18 Short story.

When grandma told me of the iron in the stars.

The hazardous history of lead.

12 | Hydrogen

What will it take to tame on Earth the energy of the stars?

14 | Naming the elements What’s in a name?

For the elements, rather a lot...

16 | Science behind the photo ‘Creativity and Curiosity’, conversations between artists and astronomers.

20 | Top 5

Some of the recognisable faces of the periodic table, as you’ve never seen them before.

23 | Carbon

Tantalum | 24

26 | Oxygen

Tantalum, a key component of electronics and the fuel to a violent war.

Sodium | 27 Pass me the salt, please!

Potassium | 30

A death sentence, a deadly dose.

An intolerable way to end.

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| Lead

Nitrogen | 22

Yellow is the new green: why urine should fertilise our crops.

4

9

Carbon makes up the food we eat.

What will happen when we’re all left hungry?

Not too little, not too much. When it comes to oxygen, you really want the goldilocks spot.

28 | Rubidium and Technetium

Nuclear radiation might sound deadly, but in medicine it’s quite the opposite.

31 | Quiz

The year is 1917. You wish to study at Imperial.

Take the chemistry test to see if you’ll make it in.

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News

by Sarah Barfield Marks

Secrets of Lithium

L

ithium’s molecular mechanism that works to treat those with bipolar disorder has finally been revealed. Lithium has been used as a medication for patients suffering from the disorder for decades, but the reason for its effectiveness has been a mystery, until now. Researchers transformed cells from bipolar patients back into stem cells to map out lithium’s response pathway. A protein associated with nerve cell communication was found to be inactive in the induced stem cells. However once lithium was added, this protein became active. In the UK, around 2.4 million people suffer from the symptoms of bipolar disorder, which include mania, depression and psychosis. By understanding Lithium’s molecular target, researchers can develop more effective drugs that work in a similar way but don’t produce as many side-effects.

A New Famous Five?

A

group of physicists are investigating the existence of a possible fifth force of nature. There are currently four basic forces of nature understood to be working within our universe. These include gravity, electromagnetism and both the strong and weak nuclear forces. It has been suggested before that there could be a fifth, when a team of researchers detected signs in the energy signature of a novel subatomic particle. The group of physicists now investigating this new force are analysing images of the centre of the Milky Way, to track the paths of stars near our galaxy’s supermassive black hole. They will then measure the gravitational influence on the stars to investigate the forces at play. If found, the discovery of a fifth force of nature would completely alter current perceptions of the Universe. If not, it could still contribute to the pursuit of a better understanding of gravity.

Coastguard

R

esearchers have uncovered the crucial role microorganisms play in protecting vulnerable islands from rising sea levels. Published in Chemical Geology, the study looked at the formation of beachrock, a mineral that protects reef islands from erosion. The team synthesised beachrock in the laboratory by replicating its various growing conditions, including growing beachrock samples with and without microbes. The samples were then analysed showing the crucial role the bacteria play in the early stages of beachrock formation. Low-lying reef islands are particularly susceptible to erosion from rising sea levels and increasingly common storms. Beachrock is one of the first lines of defence in protecting these islands from these effects of climate change.

Understanding how it forms could contribute to efforts to save areas like Australia’s Great Barrier Reef.

Pictures: Dora Zett, Thatsaphons

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A

Silicon28.08 ll life as we know it is based on the element carbon. But how realistic is it for another element, silicon, to be the basis for a new, alternative life form?

It’s been written about extensively in science fiction for many years, but could the prospect of alternative life forms actually become a reality? Certainly, the concept of life as we know it is constantly evolving; even recently organisms have been discovered on the bottom of the ocean, using the methane emitted from thermal vents to respire. But these are still, like all those that we know of so far, carbon-based life forms. How viable is the prospect of another chemical basis for life?

One prime candidate is the element silicon.

Silicon Fiction Silicon-based life has been fertile ground for science fiction writers of many genres in the modern era. In film, the xenomorphs from the Alien franchise are said to be silicon based, as are the spider-like life forms in Lost In Space. The giant space slug in Star Wars Episode V is also silicon based, along with the winged creatures that live inside it.

In the world of comics, Martinex from the original Guardians of the Galaxy is a trans-human alien with a siliconbased biology engineered to live on Pluto.

Meanwhile, Superboy has to save a race of silicon-based life forms called the Vulxans in the 1980 edition of The New Adventures of Superboy.

In the rich world of sci-fi literature, most of the life on Prism, in Alan Dean Foster’s Humanx Commonwealth novel Sentenced

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To Prism, is silicon-based. Prism’s inhabitants consider water to be ‘thick air’.

Similarly, in Isaac Asimov’s short story The Talking Stone, so-called ‘siliconies’ live on asteroids and absorb gamma rays from radioactive ores to survive. Even the trolls from Sir Terry Pratchett’s Discworld are silicon-based, functioning like supercomputers. One troll, when locked in a freezer, nearly comes up with a unified field theory!

And finally, who could forget poor old Homer Simpson having trouble pronouncing silicon when asked whether the ‘alien’ he encounters (a rather intoxicated Mr Burns) is carbon or siliconbased. His priceless response: ‘siliphone’.

Why only carbon?

If you dust off your periodic table wall chart you will see that silicon lies directly below carbon, making the two chemically similar. It is the ability to readily make and break chemical bonds that allows carbon to function so well as the basis for life. Carbon can form four bonds with other atoms, allowing it to make up the very complex biological molecules needed for life such as lipids (fats), proteins, carbohydrates and nucleic acids like DNA. Carbon can also form long, stable molecular chains called hydrocarbons. Another important feature is carbon’s ability to easily make and break bonds with oxygen, which allows respiration processes to release energy from food.

So, how similar is silicon to carbon in terms of its chemistry? Well, silicon can also form up to four bonds with other atoms. It can form long chains (called ‘polymers’) and can also bond with oxygen. But crucially,

there is plenty of it about; it is the second most abundant element in the Earth’s crust, after oxygen. It is these similarities between carbon and silicon that have led many scientists to speculate that we might soon find silicon-based life, either on Earth or elsewhere in the solar system or Universe.

However, there are some important differences between carbon and silicon that could prevent life forming from a silicon basis. The long chains that silicon forms are not very stable, and it isn’t easy for silicon to make or break bonds with oxygen. Also, when oxygen is released by respiring carbon-based life forms, it is expelled as carbon dioxide, which is a gas. Conversely, when oxygen is released through respiration from a silicon-based life form, the product is silica, a solid compound. This would be much harder to expel from the body, and might be rather painful for our poor silicon-based life forms.

What’s more, silicon does not form molecules that have the so-called ‘chirality’, or ‘handedness’, that is crucial for carrying out the biological processes of the carbonbased body. Lastly, life on Earth depends on chemical reactions that take place within a very narrow range of temperature and pH levels. Carbon-based life forms fit into this range, but silicon-based life forms do not.

Yet, the dream of silicon life might not be over for several reasons. Already some life forms on Earth have manipulated silicon into their biology. One example is the microscopic particles of silicon dioxide found in some plants like certain types of grass. Also some forms of algae are known to have incorporated silicon dioxide into their skeletons, whilst silicic acid is found

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by Peter Fox

in our hair, nails and skin. Perhaps more excitingly, the prospect of other worlds in our solar system, galaxy and beyond, might prove to be the saviour for silicon-based life.

Silicon heavens Planetary scientist Sara Seager and her colleagues at MIT are hoping to use the new James Webb telescope, which will be launched in 2018, to search for other forms of life on exoplanets planets that lie outside our solar system. Exoplanets orbit stars and thousands have already been discovered.

Seager and her fellow researchers will be looking for out-of-equilibrium elements in the atmospheres of these exoplanets. Out-

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of-equilibrium elements are those used in biological processes: oxygen and methane.

These biological signatures can be used to determine if life exists on exoplanets, and by easily identifying the type of element, what basis the life takes, be it carbon or another element such as silicon.

We might even hope to find silicon-based life forms within our own solar system, for example on the moons of Saturn or Jupiter.

Titan, the largest moon of Saturn, is one such possibility. Titan has no oxygen in its atmosphere and all of its water is in frozen form, so silicon is not oxidized away into inert rocks like it is on Earth. There is also liquid methane on the surface of Titan, which would be effective at dissolving silicon. However, it isn’t all good news;

there is still a lot more carbon around and most of Titan’s silicon is locked up deep below its surface.

Although the imaginations of some of the finest sci-fi writers have conjured up exciting possibilities for silicon-based life forms, if we are to find alternative life of this variety, we might need to reduce our expectations. The reality is likely to be a more primitive form of silicon-based life, at least that seems to be what most experts are telling us. But then again, experts can sometimes get it wrong. So, there is still a glimmer of hope yet for our silica block excreting extra-terrestrial. Ouch!

Picture: Lisa Pettibone

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mercury200.59

by Tori Blakeman

M

ercury, an element that can be both deadly and unassailably safe. Knowing the difference might save you from madness.

Mad Hatter’s Disease. We’ve all heard of it. It’s at the centre of Lewis Carroll’s famous Mad Hatter character in Alice in Wonderland, and affects the protagonist in the new hit podcast, S-town. I’m also sure most of us have been announced ‘as mad as a hatter’ before, after a particularly silly moment or two.

Both elemental and methylmercury are extremely toxic to the central and peripheral nervous systems, as they are able to penetrate the blood-brain barrier.

If ingested or inhaled, mercury can get into the cells of the nervous system where it reduces cellular processes such as RNA production and protein synthesis, ultimately leading to cellular degeneration and cell death.

It turns out that hatters did go mad, thanks to poisoning from mercury (Hg); the naturally occurring element that is found in air, water and soil. Old England hat-makers of the Victorian era used mercury to stabilise wool when felting fur from animals such as rabbits. It was this technique that exposed hat-makers to long-term inhalation of the element, which ended up causing chronic neurological damage.

Due to such poisonous effects, mercury has largely been phased out from many processes and products in which it was once commonplace: batteries, lamps, thermometers, light bulbs and felt production are some examples. It has now even made the World Health Organisation’s top 10 list of chemicals posing a major public health concern. Despite this, today the element is still, surprisingly, present in commonplace medicine, such as in silver dental fillings and as a preservative in vaccines.

So, why has mercury been phased out for some uses, but not others? Mercury exists in various forms, all of which have varying toxic effects. Elemental mercury, the raw element found within the Earth’s crust, is pretty safe when left untouched. That is, until it’s released into the atmosphere by volcanic activity, or, more likely, human activity such as coal burning. Once in the environment, elemental mercury is naturally broken down by bacteria into its organic form, methylmercury.

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The symptoms of mercury poisoning vary according to exposure, but are largely determined by the areas of the nervous system most vulnerable to the element: the sensory spinal ganglia and the cerebellum. The sensory spinal ganglia are the nerve fibres that relay information from the muscle and skin to the spinal cord, conveying feelings such as pain, temperature and touch. The cerebellum is the area of the brain situated at the back of the head, at the top of your neck, and is important in maintaining posture, and coordinating and learning movements.

Exposure to even small amounts of mercury can therefore cause serious health problems, affecting senses as well as movement. If inhaled regularly, the famous Mad Hatter’s disease, or Erethism

mercurialis as its medically known, manifests as tremors, pathological shyness, irritability, depression and delirium.

Even worse, chronic ingestion can have profound effects in the form of Minamata disease. Between 1932 and 1968 in Minamata, Japan, vast quantities of mercury were released into the sea as chemical waste from factories, causing methylmercury to accumulate in the tissue of fish and shellfish. Entirely unaware, the local fishing population continued to consume their seafood, resulting in widespread insanity, paralysis, comas and even death.

The contamination was so far reaching that fish today are still ridden with mercury, and the consumption of fish and shellfish is now the most common reason for exposure to methylmercury. Yes, mercury is present in seafood, but no, you will not get Minamata disease if you eat it. The amount of mercury ingested via seafood today is approximately 0.3 grams in a lifetime; far too small to cause a problem. Unless, perhaps, if you’re a member of a subsistence fishing population from Brazil, Canada, China, Columbia or Greenland, where up to 17 in 1000 children can present with cognitive impairment.

The not-so-toxic form of mercury is ethylmercury, found in thiosermal, which is used in very small amounts as a preservative in some vaccines and pharmaceuticals. The reason ethylmercury isn’t as poisonous as other forms is that once it is within the body, it is rapidly broken down and so does not accumulate within the cells. There is therefore no reason to worry about mercury poisoning the next time you get a vaccine. The World Health Organisation has continually reviewed the use of thiosermal in vaccines and always reaches the same conclusion; that it poses absolutely no health risk.

The mercury used in dental fillings has no health risk either. Mercury is present here as an amalgam comprising of about 50% mercury, combined with silver and small amounts of copper, zinc or tin.

Amalgamating the metal like this renders it inert, and therefore non-toxic. There remain concerns of mercury vapour release on chewing, however, all studies to present have been inconclusive.

Mercury is a fascinating element that has been utilised for millennia for numerous reasons. Considering its toxic effects, it is essential that mercury science now shifts to reducing its use and anthropogenic release to relieve danger to both health and the environment.

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Lead207.20

by Amy Thomas

F

rom the fall of the Roman Empire to severely sick factory workers, we have had a long journey with the hazards of lead. It is surely time for the industries using it to find a new route.

Another dangerous element, lead (Pb), has been a topic of public health concern due to its damaging effects on the human brain. Although the UK has restricted the unnecessary use of lead, there are still many developing countries that are effected by lead contamination. In 2013, it was thought that lead poisoning caused 853,000 deaths, and recently protesters in America have been drawing attention to the dangerous consequences of lead poisoning in children.

Lead is the most commonly used nonferrous (non-iron containing) metal and serves a multitude of purposes in industry. Lead can easily form alloys with other metals as well as undergo chemical reactions that allow the generation of a voltage in batteries. In the past, paint has also contained lead to speed up drying and increase durability; however, governments have since tried to restrict distribution of lead-based paint.

Although it is a versatile material for industry, unlike other metals, it has no benefits to the human body. As well as having no biological use, it is highly toxic to bodily systems and can cause irreversible damage in the kidneys, the cardio-vascular system and the reproductive system. Most prominently, lead has neurotoxic effects that are devastating in the developing brains of children.

Lead is particularly dangerous to the developing brain due to its interference with cell communication. Complex brain functions like learning and memory are driven by a highly dynamic process known as ‘neuronal plasticity’, literally ‘like plastic’.

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This is where neuronal connections are created, altered and shaped to change the organisation of the brain. Some of the psychological effects of lead poisoning are due to its interference with the special receptors that are involved in brain plasticity; disrupting the finely-controlled communication between the neurons and surrounding cells. Since brain plasticity

is vital for learning and memory, this particular element is not a welcome visitor in our main control room. But, lead also has other weapons in its arsenal for attacking the human body. It can stop the supply of an essential anti-oxidant in our cells, called glutathione, which would normally get rid of vicious reactive-radicals that damage DNA structure and cell membrane.

Although we’ve only known about the more detailed neurological effects of lead in recent years, incidents of lead poisoning date back as far as ancient Anatolia. As early as 450-380 BC, Hippocrates documented health defects like gout and abdominal pain following the consumption of contaminated food and wine. Later, it was no surprise that many wealthy Romans also

experienced similar illnesses, considering that Roman cooking utensils, wine urns and plumbing systems were all made with lead. An average Roman’s lead intake was estimated to be around 35 mg/day - 250 mg/day compared with today’s average of 0.3mg/day. Some historians believe that lead poisoning was a prominent cause in the fall of the Roman Empire, although this remains speculation.

During the early 20th century, factory inspectors started to notice that more and more women working in the ceramic industry were barren and children were getting severely ill. We now know that lead is particularly toxic to the foetus, disrupting processes involved in neuronal communication during development.

Although the government made some changes to the law to reduce the extent of lead damage, Tetraethyllead began to be added to petrol in 1922 as a cheap way of improving engine performance in the USA, UK and China. Not long after, there was an outbreak of acute neuropsychiatric disease in production workers as this particularly dangerous form of lead can pass through the skin. About 80% of workers displayed behavioural changes and five people died within weeks. Despite this, leaded petrol continued to be distributed globally – also damaging catalytic converters in cars. It was only in the late 1970’s, when some governments began to ban lead in petrol, that a 90% reduction in mean blood lead levels was seen. Other countries, including Algeria, Yemen, and Iraq, still use Tetraethyllead in petrol today.

Around this time in the 70’s there was also a clamp-down on the use of lead in paints. This was spurred on by research in Australia, highlighting how the widespread use of these lead-based paints through the late 19th century caused neurological disorders and deaths in children. Lead paints were banned, first in Australia in 1914, in the USA in 1978 and not in the UK until 1992!

I’m not sure why the phrase ‘crazy-as-apainter’ didn’t catch on as much as ‘madas-a-hatter’ but the consequences of lead poisoning are every bit as potent.

Pictures: Helena Spooner, ZoranKrstic (left), Maddy Dench (right)

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phosphorous30.97 2 helium4.00

15

by Rachel Gillespie

P

hosphorous and helium are two wildly different chemical elements, but have one important thing in common: they are vital resources that mankind has been frittering away and could soon be much more difficult to find

Helium: not to be taken lightly

From party balloons to the ultimate chipmunk impression, helium is known for its ability to bring out the inner child in everyone. Yet, entertainment value aside, this noblest of gases has played a notable role in our recent history, and we now use 227 billion litres of it every year.

Sucking in a lungful of helium actually demonstrates one of the key properties that make it so useful to us. Comprising only two protons, two neutrons and two electrons, helium atoms are considerably lighter than the atoms of atmospheric air. This property, together with its incombustibility, made helium the ideal gas for filling US military airships in the 1920s.

Helium also boasts the lowest boiling point of any element, at -269oC, rendering liquid helium an irreplaceable coolant for the space industry, superconducting magnets in MRI scanners, and even the Large Hadron Collider (LHC). Mixtures of helium, nitrogen and oxygen are also used as breathing gases for deep sea divers and those working under pressurised conditions.

Despite being one of the most common elements in the universe, here on Earth helium is relatively rare, as it can escape gravity and leak away into space, forever lost to us.

The gas itself is produced over millions of years from the decay of radioactive elements in the Earth’s crust. It then accumulates in natural gas deposits, from which it is usually collected as an industrial by-product.

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Currently, the largest supplier of helium is the US National Helium Reserve in Texas.

First set up in 1925 as a strategic store for military blimps, the plant accounts for 35% of current world production. However, with the rapid growth in demand for helium that came with the rise of the technology industry in the mid-1990s, the US government decided to recoup the cost of storing the gas by selling it off gradually on the open market. And by 2021, the reserve will have shut its doors altogether.

So, what does this mean for helium users worldwide? Alarm bells have started to sound as we’ve had a taste of what shortages might mean; prices have doubled since 2000, and have varied erratically over the past decade, with different US buyers paying anything from $6.50 to $35 per litre in the same year.

Whilst large industrial consumers like the military can handle such price fluctuations, the unpredictability has proved detrimental to small laboratories on tighter budgets, many of which have been forced to shut down operations at last minute.

“Helium is absolutely essential to MRI production,” said Tom Rauch of American pharmaceutical giant, GE Healthcare. “If the supply constraint… goes unabated, it could be very harmful to patient care.”

But just how close are we to falling off the ‘helium cliff’? In 2014, it was estimated that global helium reserves would be enough for about another 117 years. On top of this, 2016 saw a ‘game-changer’ in the global helium landscape when, using a new exploration approach, geologists from Oxford and Durham Universities stumbled upon a huge helium pocket in Tanzania. The deposit contains at least 1.5 trillion litres of the gas—enough to make everyone on Earth high and squeaky for around twenty minutes, or meet global

demand for a further seven years.

And Oxford’s Dr Pete Barry reckons that there may be even more to come: “We can apply this same strategy to other parts of the world with a similar geological history to find new helium resources.” But, whilst we may be

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a while away from crisis point, helium is ultimately finite and we need to start planning ahead for future generations.

One upside to rising helium prices is that scientists have been forced to get creative.

Several technology companies, including GE Healthcare, have invested in methods for capturing and recycling helium that escapes during experiments. Other innovations on the horizon include new magnets able to superconduct at higher temperatures, and magnets that can function with only ten

Phosphorus: food for thought

Phosphorus is the dark horse of the periodic table. It is true that without helium, technological innovation would face huge setbacks. But without phosphorus, there would be no food.

Phosphorus is essential for all forms of life; it forms the backbones of nucleic acids, is a major player in cellular energy storage, and it constitutes an essential building block of all cell membranes.

In nature, phosphorus flows between living organisms via a continual ‘phosphorus cycle’; weathering causes rocks to release phosphates to the soil and water, and these phosphates are assimilated by plants, which in turn may be eaten by humans and other animals. Consumed phosphorus is then returned to the soil through decay and faeces to support further rounds of plant growth.

However, human activity has broken this cycle, leaving us facing a shortage of usable phosphorus. The problem began in the mid-19th century when, struggling to produce enough crops to feed a rising—and ravenous—population, farmers noticed that spreading guano (phosphate-rich bird excrement) over fields led to impressive improvements in crop yield.

Soon after, the first mines for extracting phosphate ore were opened and from here stemmed an industrial breakthrough that would change global agriculture forever – the synthetic phosphate fertiliser. Without this development, mankind could produce only half of the food that it does today, and demand for fertilisers is escalating at nearly twice the rate of the human population.

litres of liquid helium, in comparison to the 5,000 to 10,000 litres currently required.

Yet, supplies of phosphorus are finite. The high-quality phosphate reserves on which we have relied thus far are starting to run dry, forcing us to turn instead to low-grade deposits, from which extraction is trickier and more expensive. The higher cost of extraction has led to an increase in the price of phosphate fertilisers, which in turn directly influences food prices. Such price hikes hit poor nations the hardest, and have historically been a recipe for socio-political instability; a six-fold rise in fertiliser prices during the 2007 food crisis sparked violent riots across Africa and Asia.

Only time will tell whether our efforts amount to anything and until then, let’s not wave goodbye to that last helium balloon just yet—enjoy the party instead!

Is it time to panic? Not quite—for two reasons. First, there are still a few large mines in operation, and depending on which scientists you ask, there remains

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enough commercial and affordable phosphorus on Earth to last us anywhere from another 30 to 350 years. However, 75% of these remaining reserves are controlled

by Morocco. So, we will be relying on the Moroccan government to set prices responsibly to wean the world slowly and gently from its phosphate habit. Second, unlike helium, which once lost, is lost forever, the majority of mined phosphates that we scatter around the globe are ultimately retrievable.

Yet, of the 220 million tonnes of phosphates mined every year, a negligible amount is returned to the soil; instead the waste is channelled to sewage systems, eventually ending up in the sea. How can this be rectified? To start with, we simply need to be more conscientious about how much we waste. After all, it has been estimated that less than a third of the phosphorus spread over fields is assimilated by plants; the rest accumulates in the soil or is washed into river systems, where it can cause extreme harm to aquatic life.

Reassuringly, the issue has not been overlooked by the world’s major policymakers, which have started to regulate phosphorus use. For instance, several countries have now banned the nonessential use of phosphates in detergents, and 2013 saw the establishment of the European Sustainable Phosphorus Platform (ESPP), a multilateral organisation created to find long-term solutions for phosphate sustainability in Europe. In addition to minimising waste, an option currently in the works is smart agriculture, in which plants and livestock are genetically engineered to use phosphorus more efficiently, reducing waste and the need for fertilisers.

Finally, there is the sewage option. Why not recapture and reuse the phosphorus that we flush away in wastewater? Germany and Sweden are leading the way, and in 2013, the UK’s Thames Water got in on the action, launching a reactor that turns sewage sludge into nice clean fertiliser pellets. It is anticipated that recycling in this way could supply 20% or more of the UK’s future phosphorus needs.

There is still hope. In the meantime, perhaps we should considar higher phosphate prices as the ‘nudge’ we needed to get our act together. Otherwise the world’s great phosphorus shortage could leave us all hungry.

Sculpture: Lois Liow

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hydrogen1.01

by Jonathan Bosch

H

ydrogen is the most abundant element in the universe.

Hydrogen fusion powers the stars—its potential as an energy source for humans is huge, but we are yet to harness it on a large scale.

closer to harnessing the energy of the stars?

When completed in 2025, the ITER (‘The Way’ in Latin) prototype tokamak will be the biggest fusion reactor in the world.

Tokamak reactors use a powerful magnetic field to confine the hot plasma required for fusion.

The colossal amount of energy released in the fusion process comes from the difference in mass between the input nuclei and the product, which, multiplied by the speed of light-squared (Einstein’s famous equation), leads to energy being released as electromagnetic radiation and a fast-moving neutron. Converting this energy usefully can theoretically be done in the way we’ve harnessed energy since the steam engine: turning a shaft or moving a piston by heating water. The difficulty is in getting the hydrogen isotopes to fuse in the first place. Here on Earth, without the aid of the huge gravitational mass of a star to force nuclei together, fusion reactors must reach incredible temperatures to achieve the vibrational energies that enable fusion.

This 35-year-old project is a 35-nation collaboration aiming to prove the feasibility of fusion as a large scale, carbon-free energy source. ITER will be the first device to produce net energy for sustained periods of time, where smaller demonstration plants have only been able to produce more power than they’ve consumed for brief demonstrations. With a reaction chamber capable of holding ten times the plasma volume as JET, ITER will be a scaled-up version that will demonstrate all the integrated technologies that have, and are still being, developed in smaller experiments around the globe. The timeline for this commission is still in the order of decades—it is yet to be seen whether large commercial facilities will be economically viable in our lifetime.

Research institutions around the world pour in billions of dollars—sometimes controversially—to make the process viable at a large scale, but have still failed to fully tame the reaction. The Oxford based Culham Centre for Fusion Energy (CCFE) hosts two leading fusion experiments: MAST (Mega Ampere Spherical Tokamak), the UK’s own fusion pilot, and JET (Joint European Torus), the world’s largest magnetic fusion experiment. Together, they host 650 scientists and engineers from 28 countries, including EU member states.

The purpose-built fusion laboratory has been in continuous operation since 1965, contributing to the oft-joked adage that fusion power is always 30 years away. Fusion power really should be around the corner by now. Has 60 years of research got us any

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However, fusion may not be the only show in town when it comes to generating energy from hydrogen. Another promising technology is the hydrogen fuel cell, which converts chemical energy into electricity, much like a battery does. Unlike a battery, however, the chemical fuel must be continuously replenished for the cell to keep generating power.

The technology has been historically hamstrung because of its bulk and complexity, and the need to use energy, normally fossil in origin, to produce the cell’s hydrogen fuel. This is changing with the proliferation of renewable energy sources worldwide, which enable the production of hydrogen fuel at low or net-

zero carbon emissions. The benefit for transport technologies is clear: the only in-use emission is water, and the energy conversion can be extremely efficient.

Hydrogen-powered aircraft, for example, could significantly reduce man-made carbon emissions while facilitating the growth of mass air transport. In novel designs such as NASA’s blended wing aircraft, jet engines can be modified to use liquid hydrogen instead of fossil fuel-derived kerosene. Among the technological hurdles, however, is the problem that hydrogen fuel occupies four times the volume of kerosene in its liquid form, with only half the energy density.

In the automotive world, Honda and Toyota have made an impressive push for hydrogen-powered cars, betting on fuel cells rather than lithium-ion batteries to cut carbon emissions. The Japanese government has been paving the way for this, providing incentives and boosting fuelling infrastructure ahead of the Tokyo Olympics; a gamble that might pay off in the long term.

One way to produce clean hydrogen that can power these vehicles is by splitting water molecules, in a process called electrolysis.

Again, not a widespread practice yet, but one that scientists see has great potential.

Using a Polymer Electrolyte Membrane (PEM) cell system, electrolysis can happen at relatively low temperatures and can be powered by renewable sources such as solar and wind. It’s especially attractive because water is the source; current methods rely on limited hydrocarbon fuels such as natural gas. The race is on to make hydrogen technologies competitive with fossil fuels before our carbon footprint on the Earth becomes indelible.

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LITHIUM6.94

by Jennifer Hack

L

ithium is small but fierce.

Perched at the top of the periodic table, the lightest metal of all, it burns a fiery red. It was discovered in 1817 by the Swedish Johan August Arfwedson, and gets its name from the Greek lithos, ‘stone’, owing to its discovery in the solid mineral petalite. Lithium metal was first isolated in bulk using electrolysis

by Robert Bunsen (of Bunsen burner fame) and Augustus Matthiessen in 1855, and has since found application in all sorts of unexpected places. From medicine to food, fighter planes to song lyrics, use of this element has boomed over the course of the last hundred years.

The history of lithium use starts during World War II. Lithium hydride was used as a way of storing hydrogen for use in emergency-signalling balloons, and lightweight lithium greases were used for aircraft engines, due to their ability to withstand high-temperatures.

Moving into the latter half of the 20th century, lithium found continued use in military applications, most notably in the production of tritium by nuclear fusion for hydrogen bombs during the Cold War. Yet perhaps the pivotal moment for lithium came with the conception of the lithiumion battery. Until this point, we had been lugging around heavy nickel metal hydride (NiMH) batteries in our mobile phones or relying on toxic lead-acid batteries for our energy storage. The development of the lithium-ion battery in the early 2000s allowed phones to be slimmed down and a new era of handheld electronics dawned.

What made lithium so suitable for new battery technology? Lithium is light— testament to this is its position at the top left of the periodic table. Furthermore, the high reactivity of lithium allows it to store a lot of energy, giving it a high energy density.

Both of these properties are favourable for a battery, meaning that lithium-based technology could outperform its NiMH and lead-acid predecessors.

However, safety is an issue with lithium, and the instability of lithium metal meant that initial lithium-metal-based batteries were not suitable for mass roll-out. By losing one electron to give the more stable, safer Li+ ion, new batteries could hit the market with only a small compensation in energy density, compared to lithium metal. A further advantage of lithium-ion batteries is the ability to charge and discharge for many cycles without any significant drop in performance.

With lithium-ion batteries attracting so much attention as excellent energy storage devices, research efforts have more recently been turned to the scaling up of Li-ion batteries for use in hybrid-electric and electric vehicles (HEVs and EVs), as well as for stationary power storage. Energy produced at two in the morning on a breezy night is useless unless it can be stored until the seven o’clock kettle rush. The energy landscape of the UK is rapidly changing as renewables become cheaper, now making up more than 20% of the UK’s electricity production. Both of these applications have pushed recent research efforts, in the UK and worldwide, to improve battery technology in order to match supply with the growing electricity demand.

In light of this, a wide range of alternative, Li-based batteries have emerged.

Researchers are now investigating the suitability of lithium-sulphur, lithiumnickel-manganese and lithium-silicon batteries for the full range of applications.

Building on the successes of the Li-ion battery, this new generation of battery technology aims to have improved safety and stability, use lower cost materials, minimise degradation and increase lifetime. Other recent work, which was led

by Professor John Goodenough (who, at the age of 94, is said to be the ‘father’ of the Liion battery) has focused on replacing the conventional liquid electrolyte with an allsolid-state cell, which promises to be safer and faster to charge.

Alongside the increased academic research efforts, large amounts of investment are also coming from industry, focussing on development of both materials and technology.

This is already paying dividends: the number of charging points on the UK’s streets and service stations is increasing and the price of HEVs and EVs is dropping as more models become available.

What is the future for energy storage and how does lithium fit into the picture?

There are still problems that need to be addressed, such as the long charging times of batteries, as well as the increased strain on the National Grid if a country’s worth of users wants to plug their cars in when they all return from work. However, the push to decarbonise and clean up the atmosphere is definitely bringing about positive changes and it is safe to say that lithium will continue to play its part in this revolution.

Picture: Lizzie Riach

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Naming the elements

by Allison Tau

I

n November of last year, the periodic table saw an update with the permanent addition of four of the super-heavy elements; numbers 113, 115, 117, and 118, signifying a longawaited completion of its seventh row. Per tradition, the discoverers of these elements had the rights to propose their names.

Researchers from Japan honoured their culture in naming element 113 nihonium (Nh), after the Japanese word, ‘nihon’, meaning ‘land of the rising sun’. Another joint research effort named moscovium (Mc, 115) and tennessine (Ts, 117) after Moscow and Tennessee, and the contributions of these places to research. Finally, oganesson (Og), the name for element 118, recognises Professor Yuri Oganessian, a leading researcher of super-heavy element research.

During the name vetting process, other names were suggested and petitioned for, but ultimately it was up to the discoverers to propose the names and the International Union of Pure and Applied Chemistry (IUPAC) to accept the proposals.

Historically, the names of elements were influenced by language, culture, observation, and experimentation. It was the Romans who began naming new elements in ‘-um’, a convention which has continued to the present. Currently, the IUPAC has several naming guidelines for new elements, keeping in with tradition: they can be named after a mythological concept or character, a mineral or similar substance, a place or geographical region, a property of the element, or a scientist.

The discoverers have the naming rights, but what happens if who discovered an element first is up for debate? When multiple labs are working simultaneously and competitively,

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this often leads to element naming controversies. This was the case of what is referred to as the ‘Transfermium wars’, a 40-year debate between American and Soviet scientists about who first discovered elements 102-108.

The controversy began in 1956 when two labs-one in California and one in the Soviet Union-discovered element 102 at around the same time, and so both claimed the naming rights. For the next 40 years, as both groups of researchers discovered more superheavy elements, they named them without consulting one another, resulting in a Cold War-esque head-to-head confrontation.

Since 1947, the IUPAC has had the responsibility to mediate the tensions, but it took until 1997 to reach a compromise. The two parties shared the naming rights to the two biggest elements in the dispute, 104 and 105; the Americans got rutherfordium for 104, and the Russians dubnium for 105.

Compromise is the key when scientists get personal about their right to naming. As in the Transfermium wars, the contention most often happens across international borders. What Europeans referred to as niobium (Nb, element 41), Americans long called columbium (Cb). Traces of this old name still exists in metallurgical contexts in the United States, even after IUPAC officially adopted the name niobium in 1950, following nearly 150 years of controversy.

This act was a compromise for accepting the American name tungsten for element 74 over the European usage of ‘wolfram’ for the same substance (but the chemical symbol W for tungsten remains).

A final example related to the naming of elements is meitnerium (Mt), element 109, a sort of consolation for a famous Nobel

Prize controversy. Of the 19 elements named after scientists, meitnerium is the only element solely named after a woman, Lise Meitner, as Marie Curie shares the honour of curium with her husband Pierre.

Meitner corresponded with her collaborator Otto Hahn, despite facing persecution in Germany in the 1930s as a Jewish woman and having to flee her home city of Berlin to exile in Sweden as a result of war tensions. Her suggestions ultimately led to the discovery of nuclear fission, but in 1944, she did not share the Nobel Prize in Chemistry, which Hahn received.

Like other instances of women being unrecognized for their scientific contributions (the most well-known of which is Rosalind Franklin), Meitner’s many other prizes and awards on her work were overshadowed by the Nobel Prize snub.

The issue was brought up again during the Transfermium wars, but because meitnerium was the only name proposed for element 109, it was accepted immediately.

This act is perhaps better considered not as a consolation but instead as a greater recognition for Lise Meitner and her work than her omission from the Nobel Prize.

The periodic table is at first glance a steadfast scientific tool, but it took centuries of effort, beginning with Mendeleev arranging by hand a deck of cards with all the known elements written on it to the most recent additions resulting from advanced highspeed atomic collisions. Behind each of the one or two-letter symbols is a story of how those elements were discovered in the lab, and a decision to give it a name, an identity.

These naming controversies and disputes are a reminder of the highly-personal and social nature of building a collaborative piece of scientific knowledge.

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Americium243.06

by Marek Wolczynski

A

mericium is produced by bombardment of uranium with neutrons. It’s less toxic than other radioactive elements, and often used in smoke detectors. When it was first discovered in the University of Chicago in 1944, the periodic table was being restructured by the American chemist Glenn Seaborg. The new element was to be located right below europium, and was hence named, by analogy, after its place of discovery: the United States of America.

Several other elements in the periodic table are named after places, such as germanium and polonium, highlighting the fact that national identity often influences the progression of science.

Of course, patriotism plays a key role in creating a sense of unity between us, and different national identities are an inevitable part of our existence. Is there a place for patriotism in science? And to what extent can, or should, science be nationally independent?

The best example of the influence patriotism can have on science and technological progress was the international Space Race between the Soviet Union and the United States. After both nations announced that they would launch satellites into space, the Soviet

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Union beat the US to it, launching Sputnik 1 in October 1957. This was a tremendous step that not only gave us the opportunity to explore the cosmos but also proved the Soviet’s technological capabilities to the rest of the world. As a result, the Americans were forced to speed up their research and improve their space programme, enabling Neil Armstrong to be the first man to walk on the Moon in 1969—“One small step for a man, one giant leap for mankind,” and of course, for America. The Space Race proved that competition between nations can lead to quicker developments in technology and science, and that patriotism can be valuable to a country's progress.

Not only do scientific breakthroughs improve knowledge, but they also showcase a country’s power and technological prowess on the international stage.

Patriotism also benefitted science with the creation of the American National Science Foundation. This governmental agency was founded in 1950 to focus on technological improvements in the United States, supporting research and scientific infrastructure in myriad disciplines, from biological sciences to engineering and geosciences. The Foundation invests over seven billion dollars into not only experiments, but also raising public awareness about the importance of scientific research.

On the other hand, experts from across the world have to work together to tackle today’s scientific challenges, leaving national identity aside. Consider the Human Genome Project, which mapped the complete sequence of genes that make up a person. Scientists from 20 universities across the globe participated in the sequencing process, enabling us to better understand the causes of our genetic traits and diseases. Today’s science requires mobility—travel and international cooperation play a pivotal role in gaining new ideas and experience while doing research. Funding schemes for overseas students and researchers recognise the importance of bringing together bright minds from all over the world.

The desire for nations to keep up and show off in the world of scientific research has clearly encouraged progress, and even led to breakthrough discoveries. There’s nothing wrong with a bit of national pride showing through in the periodic table.

However, national science can only take us so far—the international pooling of resources and ideas is an essential part of modern scientific progress. It will take us further, and faster, than trying to compete against everyone on our own.

Pictures: Bruno Martin (left), Karolina Jankiewicz (right)

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science behind the photo Creativity and Curiosity, Conversations between Artists and Astronomers Gillian McFarland, Ione Parkin and Alison Lochhead are three contemporary artists who work alongside astronomers and space scientists from Imperial College London and other research institutions. They are interested in exploring the rich imagery of space, engaging in creative dialogue on current thinking and research about the universe. Through ongoing interactions with astronomers and planetary geologists they interpret the universe through the materials of their own disciplines—painting, sculpture, printmaking and drawing. For more information about the ‘Creativity and Curiosity’ project, visit our website, isciencemag.co.uk

Gillian McFarland, bottom left

Working with Master Craftsman Graeme Hawes, Gillian’s work recreates events after the Big Bang through glassblowing. Her work is grounded in astronomical research, as the extremes of heat, rotation, expansion and contraction are at play alongside an exploration of chemical elements found and introduced into the glass. In her ‘Planetary Globes’, different elements are mixed with batch—the transparent glass, made up of silicon dioxide, calcium oxide and sodium oxide—to create colour.

Ione Parkin, top right

Ione Parkin’s work ‘Heavy Metals’ is a mixed media work on paper involving ink, PVA, acrylic, powdered iron oxide pigment, powdered oxidised copper and graphite. It is part of a group of abstract works exploring her interest in planetary surfaces and the dynamic processes of extreme heat, compression and chemical reactions of raw elements. This is a restless process-driven image, textured through the tactile exploration of materials and the physical fracturing and compacting of the surface.

Alison Lochhead, bottom right

Alison’s sculptures work with the transformation of materials such as iron, rocks, clays, minerals and silica in a kiln, or furnace, and they are inspired by the impact of heat, explosion and disintegration. As in space, creation and destruction are inextricably linked, in a process which mirrors the human condition. She pours molten iron over different materials; some fuse together, some pull apart, some melt, and some retain their integrity, despite having melting points below that of iron.

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iron55.93

I

'm frightened by iron, and it's my grandma's fault. I never enjoyed visiting her until I was grown up. Every time I went to her house, I knew I would leave full of doubts and angst.

I knew that she would question every choice I made, every word I used. When I went to her house, she would welcome me with the door already open, sitting at the big table of her living room, holding a pair of sewing scissors. She talked to me without looking into my eyes, focused on shredding the cloth whilst holding a needle in her mouth. I was always afraid it would escape from the narrow grip of her lips, and then throttle and sting her. She spoke with her lip half-open like someone holding a cigarette. She used to wear elegant and bright coloured clothes, like those which she displayed in her atelier. Her perfume, diffused in every room, was enhanced by the energy she released. I could never figure out whether that energy was positive or negative. She would have said that, if I couldn’t figure it out, it was probably a stupid question.

I have always found my grandma a bit intimidating, even when I thought I had become tougher than she was.

Her tongue was as sharp as her scissors. Firm and assured, she could cut through comforting thoughts as easily as she did through cloth. She used to destroy the foundations of what is thought to be obvious. She would cut them off and keep only what she needed. She didn’t do anything with waste; she would generously leave the small and useless pieces of cloth and words that she had cut to those who wanted to do something with them. She despised those people.

One thing I liked about my grandma was that she always cut with a purpose, she never destroyed anything for the sake of it. She cut the clothes to sew them together and make wonderful dresses, and she cut off the nonsense to sew together only relevant words, building wonderful metaphors to give some meaning to the world. “Words are expensive, like cloth,” she used to say, “words are important”. For example, she didn’t want to waste words telling me some nonsense, when she decided that at the age of three I was old enough to stop believing in Santa Claus.

She decided to tell me the story of “Why people think it is important that children think Santa Claus exists”. She liked to educate me without my mother noticing her intervention.

She used a certain connection present between us, that of understanding subtle metaphors. She particularly favoured analogies to put the big patterns of the world within the

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by Silvia Lazzaris small ones: the structure of a galaxy that resembles a neuron, the veins of leaves that resemble the lines of our palms, a nut that is reminiscent of a brain... When telling her stories, she didn’t point out analogies within my life, she would just let me find the connection—or not. In most cases I think she knew I would do it. Sometimes I wish I hadn’t understood, at others I couldn’t stand her for more than a while.

Yet, her truths have never shaken my life more than her story of iron. And there hasn't been a moment when I have questioned her love for me more than in the moment she talked about iron. It was a warm Sunday morning in June, we were on the train that would take us to St Albans for my cousin’s first communion. I was 24. We were in a four-seat: I was next to George, she and my mum were in front of us.

My mum was on the phone with a friend. Every now and then she would stop to make jokes. They would always be directed exclusively to George, the only one who she still respected. George and I had been together for five years, and he had proposed some weeks before. In those weeks, everyone was congratulating and asking when we wanted to celebrate the wedding. We laughed, replying that we didn’t know yet. In those cases, the difference between him and I was that, while he sought my gaze, I made my best to avoid it. George was a good guy. He also belonged to a good family. My mother liked his family very much, and I was embarrassed at her many attempts to ingratiate herself with them. He was a good guy, in such need of love... much more than me. That’s why he needed gestures that I absolutely didn’t need, such as holding my hand, stroking it continuously, seeking my gaze, or repeating to me that he loved me. He was a handsome guy. The first time I saw him, his scent had attracted me like a magnet. Now it seemed to me that it had changed, or perhaps I had just become accustomed to it. He was pretty clever, too, or rather he had skills that I didn’t have, and therefore excited me. For example, he could quote entire movies, and he could do animal impressions. He could bray, crow, bark perfectly. I could never have done that. It was exciting. Sometimes, as on that Sunday, he seemed a bit dumb.

I was nervous already, from his lack of commitment to this ceremony. We were all well-dressed, except for him. He was wearing a T-shirt and trainers. He simply didn’t care about it. He knew I was nervous, and was constantly trying to hold my hand. That made me even more nervous, so I repeatedly brushed him off. My grandma, elegant in full

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turquoise, was looking out of the window, but I was sure that from the corner of her eye she saw everything. I was looking at my phone screen to avoid real communication, rude to everyone just to avoid George.

only a few days a quantity of energy that is comparable to that irradiated by the Sun in billions of years. Then the star cools down and develops an indescribable frost, or turns into a black hole”. She paused again.

He stroked the back of my hand. I ignored it and kept replying to messages on my friends’ group chat. He looked at my phone only to show to the other two that we were still doing something together. And so when I wrote something funny, he laughed loud and looked at me. I ignored him. I felt he was looking at my face, I felt his eyes on me. I was so annoyed. Then he was giving me long kisses on my cheeks and forehead, and while he continued to stroke my hand, I sighed. I wanted to get rid of that burden as you do with a duvet on a summer night, or with an annoying insect walking over your body. I wriggled away with small movements. Then I felt unfairly cruel, and I put my hand on his—motionless, almost to hold his still. On that day I couldn’t help it, I was physically repelled by George. The worst part of it was that I felt provoked by too much love.

It was breaking my nerves. Everything I had always felt for him, both positive and negative, had been passionate and violent, but lately it had become rather sloppy. And the most unsettling part was that the sloppiness had been growing since the moment I said “yes” to his proposal.

I could already see that the stars were not what my grandma was talking about. She was talking about us. About me and George. My relationship with George was a fat, exploding star, about to leave a black hole in my heart. I felt extremely irritated. I remained silent. George, instead, proclaimed: “Ah, the sad story of the stars!,” as if to give a title. He wasted those six words matching them in a meaningless way with an idiotic expression on his face. Basically, the last thing he needed to do in front of my grandma. He clearly hadn’t realised what was going on. So she went on, becoming nastier still: “It may sound like a sad story, dear George. But in fact, this last explosion of energy that produces the end of the star allows the creation of new atoms and of all the nice things that are made of them. Gold, for example, wouldn’t exist if this did not happen. Well, not even human beings”.

I felt my grandma’s eyes on us, active and judgmental, which made me even more irritated. At some point she asked me: “What’s happening? You’re looking rather bleak”. “The doctor said I’m lacking iron. Maybe it's that,” I said dryly.

She laughed and, then, looking at the window, attacked: “So many stories about iron. Without it, we wouldn't even live. No oxygen would reach our tissues. If we lack iron we feel weird and depressed. Yet, for the stars, when the iron phase comes, it’s all over soon”. I knew that if I ignored the hook, nothing would happen and I wouldn’t have to learn any shaky truth. But my curiosity was inexorable. I knew it was wrong to let her comment on the situation with one of her metaphors. But, as always, I dived into my own selfdestructive pool. “Why, what happens when the iron phase comes?”

Satisfied, she went on: “So, as you may know, every star was born, lives and dies. And the length of a star’s life depends on its mass: smaller stars, for example, live longer. Greater stars burn faster. In any case, at the beginning, the star is very stable”. My mother was still on the phone and gestured to my grandma to lower her voice. George listened attentively.

I was terrified. “There is a constant nuclear fusion, and the mechanism is simple. It begins with hydrogen, which blends and turns into helium, and then the helium turns into carbon, and carbon into nitrogen, and so on, until it reaches iron”. She paused. “When iron arrives, the process is interrupted, because iron fusion does not produce energy.

And yet, it requires some. So at some point, when there is no energy left, the star collapses and explodes, producing in

I hated her. “I don’t see how the iron of the stars relates to the iron that is missing in my blood tests, grandma,” I said. George thought my answer was rude, and tried to get back on her side by clumsily telling me off: “Oh, come on Anita! It’s still a beautiful story!" And then to her: "But how come you are so interested in iron?” I could see she would enjoy making fun of him. He seemed far less intelligent than usual, beside her. “Well, I think it’s because I can see how this relates to human lives. Sometimes you get to the iron phase, and everything you’ve built has gone. It’s been used, it’s over. When iron comes, energy is not produced anymore, but only demanded. It eats you until you collapse.

Everything has been consumed. There is nothing left to use. You collapse and you can only wait for the explosion to generate energy again. Can we blame ourselves when this happens to human relationships? If this happens to the stars, why shouldn’t we accept it when it happens to us?”

My answer came out almost like a hiccup, with a tone of challenge: “Yes, because in the end the alternative is only between a white dwarf and a black hole, right?” George was completely lost. My grandma looked me right in the eyes. She seemed proud of me, or at least as proud as I was angry. “Well, my dear, my heart is full of black holes, but I never gave up to a life without energy. And I’m fine." In that moment, I became aware that mum’s eyes were also on me. I hadn’t realised that she had closed her call. She turned to grandma: “We know that you are fine with your sewing scissors, mum, and that you don’t need anyone or anything else,” she said with irony, “but not every hardship in life can be cut off and be done with!”

It’s hard to explain how I felt in that moment. Two things startled me. Metaphors were not our secret language; my mum was in on them too. And for the first time, I had no idea who was right.

Picture: Leanna Crowley

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Top five: Elements We Thought We Knew

by Aran Shaunak

Hydrogen: Doesn’t Believe in Labels (73.9% of the Milky Way)

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hydrogen

ydrogen is a familiar friend: an essential component of water and the most abundant element in the universe. Yet still it surprises us–despite being firmly labelled a ‘non-metal’, when put under immense pressure (around four million atmospheres) at extremely cold temperatures (near absolute zero), hydrogen suddenly behaves like a metal. ‘Metallic hydrogen’, so-called because it conducts electricity, was predicted back in 1935 but was first observed this year, although some scientists remain sceptical as to its existence.

Helium: Doesn’t Play by the Rules (24.0% of the Milky Way)

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He helium

elium gas is an honoured guest at every children’s party, but in liquid form helium behaves as a ‘superfluid’– a state of matter with zero viscosity, flowing without friction over any surface. In the same way that water creeps up a straw due to surface tension, liquid helium can flow up the side of a container–but since it does so with no friction to slow it down, it doesn’t stop like water. Instead, it defies gravity by climbing vertical walls like a sinister alien slime, escaping its container entirely.

Search ‘helium superfluid’ on Youtube and give yourself nightmares.

Oxygen: Gets Excited, Makes a Scene (10.4% of the Milky Way)

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oxygen

xygen is the air we breathe, but it’s also the air we stare at. When oxygen molecules are hit by high-energy particles from the sun, they gain energy and become ‘excited’. When these excited molecules relax they release this energy in the form of light, creating the green glow of the Northern Lights. Other less common colours include the lower energy red light from less excited oxygen molecules in the upper atmosphere, and the blue and purple hues produced by excited nitrogen atoms .

Carbon: Looks Tough but a Big Softie (4.6% of the Milky Way)

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carbon

arbon, the building block of all life on earth, is one big contradiction: it’s both the hardest and the softest element of all.

Diamond is extremely hard, made up of carbon atoms each linked to four others by strong covalent bonds. Graphite, on the other hand, is made of sheets of covalently-linked carbon atoms that slide over one another, connected only by weak intermolecular forces. These molecular differences mean that carbon can either be the hardest mineral on the planet or so soft you can scratch it with a fingernail.

Neon: Just Lonely

(1.3% of the Milky Way) 10

Ne neon

eon is one of the seven noble gases, which form group eight of the periodic table, are incredibly unreactive – hence their nickname ‘the inert gases’. This is because they have a full set of eight electrons in their outer shell, and so don’t readily form bonds with other elements to become more stable. However, only neon is a true inert gas: radon, xenon, krypton and argon can all be coerced into bonding with oxygen and/or fluorine under the right conditions. Neon stands alone as the only element that does not react with any others. Perhaps an anagram of ‘none’ is a fitting name.

Picture: Victoria Westerman

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H

HYDROGEN

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Ne NEON

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O OXYGEN

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He HELIUM

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nitrogen14.01

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by Katharina Kropshofer

ood starts with N, not with F. Every piece of bread we eat, every salad we prepare, has been in touch with N: nitrogen. According to the International Fertilizer Association, 450 tonnes of ammonia (NH3) are produced every year as fertiliser. But nitrogen use efficiency is less than 50%, which means only half of the nitrogen we put in our fields ends up in our food, and it comes with severe environmental implications.

There is an alternative—but one that we are, literally, flushing away.

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Modern agriculture would not be the same without the Haber-Bosch process, which earned Carl Bosch the Nobel Prize in 1931. Since its invention, the human population has almost doubled. The background is simple. Nitrogen makes up 80% of our atmosphere. When it reacts with hydrogen under high energy, we get ammonia. Processed further into ammonium nitrate (NH4NO3) and urea (CO(NH2)2), this nitrogen compound becomes a significant nutrient for all plants. It seems straightforward enough, but the procedure has a concerning impact on our ecosystems.

Ammonia tends to flow off from fertilized fields. It can accumulate in waters and cause hypoxia, or ‘dead zones’, through a process known as eutrophication. Excessive nutrients from fertilisers feed the wrong kind of organisms, leading to an unwanted algal bloom. When those algae die, bacteria decompose them, exhausting the oxygen in the water. These low levels of oxygen create a hypoxic zone, which supports no more

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life and destroys the water’s ecosystem.

Generally, only a third of the ammonia makes it to human bodies. The rest either ends up in rivers and lakes, or returns to the air as the greenhouse gas nitrous oxide (N2O). Even if it does stay in the ground, an excessive amount could pose yet another threat to the ecosystem, by making the soil too acidic.

Without neglecting the positive effects this process has had, namely most of us being alive, it does not seem as revolutionary when we consider that we already produce our own fertiliser, in the form of urine, which is drained into sewage systems.

There, the valuable nitrogen is removed from the chemical compound urea and converted into N2, the gaseous nitrogen found in our atmosphere. In the HaberBosch process, we undo all our hard work to turn it into urea again—consuming a massive one percent of the world’s energy to do so. Not only are the economic and environmental disadvantages tremendous, it is also a fairly laborious circle, considering how much simpler using pee would be.

Human urine is full of nitrogen and phosphorus, the ingredients for a perfect fertiliser. Since we literally flush this valuable urine down our toilets, we would need a system which collects the substance to recycle it. The Rich Earth Institute in Vermont is researching advantages of using human waste as a resource to improve our impact on the environment.

They say that with fertilizers from one adult’s urine, up to 150 kg of wheat could be grown in just one year. Not only would this decrease the amount of nitrogen pollution

in wastewater (caused by human waste in the first place), but it would also save some of the 5.5 trillion litres of drinking water which is used to flush our toilets.

While the Rich Earth Institute is working on the bigger implementation of ‘peecycling’, a Swedish research team has designed NoMix toilets, which separate liquid from solid excrement right in our bathrooms. In a sewage system, human urine only contributes one percent of the wastewater. The NoMix on-location urine collection system prevents the need for a complicated splitting process once all wastewater has been mixed. If it exists, what is keeping us from implementing this?

The technology is on its way but still far from being an add-on to every household, with prices between $1,500 and $2,000 per toilet. General negative reactions also suggest that this idea pushes many people outside of their comfort zones. Men would have to sit down to urinate in a NoMix toilet, which puts cultural norms and feelings of convenience under the gun.

Besides, a sense of disgust and unease seems to be triggered by using human waste for something that will touch our mouths later.

Earth has many hungry mouths to feed.

Given our dissatisfying, harmful and circular approach to fertilising, it is time to consider the alternative. Most nitrogen currently ends up in our freshwater reservoirs instead of our food. Let’s change that. Let’s send it directly from bathrooms to farms.

Picture: Emils Gedrovics

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carbon12.01

by Samantha Oon

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ur population is flourishing, but we aren’t growing enough fare to feed it. How we harvest the huge quantities of food required will be one of the biggest battles we face. Think of carbon. It’s in the fuels we burn, in the air we breathe, in the clothes we wear. It’s essential to life as we know it–especially in the form of food. Considering that around 793 million people worldwide currently lack access to sufficient nutrition for a healthy and active life, food production and security more pressing than ever. How will we feed the nine billion strong population predicted for 2050?

At the root of this problem is the very human love affair with meat. Paleoanthropologists Leslie Aiello and Peter Wheeler proposed that eating calorie-dense meat instead of low-calorie plants helped our ancestor, Homo erectus, evolve larger brains. Since then, humans have relied on energy-dense foods like meat for survival and evolution for hundreds of thousands of years.

With the advent of agriculture, producing food for communities became even easier, and so human populations flourished.

What was once a luxury became an everyday component of meals, as farmers reared livestock for meat and dairy.

Flash forward to today; the average Brit is estimated to eat around 80 kg of meat per year, and meat consumption is still increasing around the world–particularly in developing nations. This rising demand comes at a social and environmental cost, as we start to rely on food production on a massive scale. According to the Food and Agriculture Organization (FAO) of the United Nations, about a quarter of the world’s ice-free land is used for livestock grazing, and farmed animals contribute

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seven percent of the total greenhouse gas emissions. Some experts offer bleak predictions that dwindling resources will make farming meat less viable and more expensive. Henning Steinfeld, an agricultural economist from the FAO, has posited that by 2050 beef could be "the caviar of the future. Beef will be what salmon was fifty years ago".

Unsurprisingly, the United Nations Environment Programme (UNEP) is urging the global community to move away from diets rich in meat and dairy. Researchers have modelled the effects of reducing meat and dairy consumption around the world, and found that increased adoption of vegetarian and vegan diets could have region-specific health, environmental and economic benefits.

Another avenue for sustainable human cuisine is adopting new sustainable sources of protein–specifically the kind you can find in your gardens. Crickets, mealworms and termites don’t figure into most people’s definition of palatable, but they are crucial ingredients for many cultures around the world. Mexicans roast their grasshoppers with seasoning, whilst some indigenous South East Asians prefer their Sago grubs fried. Even if these practices seem exotic, people in developed nations are already consuming insects with or without intention since they always tend to end up in processed foods to some extent.

The practice of entomophagy - the consumption of insects as food – may become an increasingly viable diet option despite its stigma in western society.

Raising and harvesting insects requires much less space than farming traditional livestock and emits relatively few greenhouse gases. Insects are also highly

efficient at converting food nutrients into body mass; thus requiring less feed to produce comparable amounts of protein to cows. Practically speaking, insects could be the food of the future, and the European Commission is even offering £2.65 million to the group with the best idea for popularising the eating of insects.

Whilst changing the way we eat seems an uphill battle, there are teams working towards other more sustainable methods of food production. Stem cells are being used to grow meat entirely in labs, and if the process is perfected, it will mean that beef and chicken can be produced with a decreased environmental impact. Using just small bits of muscle tissue from cows, scientists have been able to harvest stem cells and multiply enough of them to form in-vitro hamburgers. The setback though is the cost of this process; about £10,000 for one lab-grown burger. Researchers are confident that this price will be whittled down as the production of lab-grown meat is scaled up, but it remains to be seen how willing people will be to move towards cellcultured burgers and steaks.

In the end, it may be how we treat our food rather than what we eat that holds the key to achieving zero hunger and sustainable diets. The food industry already produces sufficient food to feed the world’s population, but around one third of output is discarded or spoiled during transport and storage, according to figures from the FAO. Faced as we are with the challenges of producing nutritious food and distributing it equally, it is clear that humans will have to embrace changes to our way of eating if we are to feed the planet of the future.

Picture: Allison Tau

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t is an element which can be found in almost all of our electronic devices, helping to make them lighter and be more efficient. Yet, elsewhere, tantalum is the fuel of war.

When the phrase ‘world war’ is used, many of us might think of the First and Second World Wars that set the globe alight in the 20th Century. But, for those living in the Democratic Republic of Congo (DRC) and its neighboring countries it might bring to mind a different, but no less deadly, conflict.

The Second Congo War began in 1996, when forces loyal to Congolese revolutionary Laurent-Desire Kabila sought to topple Mobutu Sese Seko, who had ruled the Congo since a Belgian-backed coup some 30 years prior. But, what started as largely a straightforward struggle between two rivals soon devolved into something far more convoluted, as more and more states and militant groups became enveloped in a conflict that has been referred to as ‘Africa’s first world war’.

Estimates suggest that over five million people died as a consequence, making it the second most deadly conflict since WW2.

At the heart of this tale of blood, death and tragedy sits a relatively inconspicuous element: tantalum.

It is difficult to look at tantalum and see how it could be responsible for one of history’s deadliest wars. A glossy, blue-grey metal that is almost completely chemically inert, there seems to be little remarkable about it compared to more exciting elements like fluid mercury. But its stability, combined with its metallic properties, is what makes tantalum so important.

You might not realize it, but tantalum is ubiquitous in our daily lives. If you pried open your closest gadget, whether it’s a smartphone, laptop or TV, you are bound to find tantalum capacitors - small energystoring components that perform crucial

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functions like helping to smooth power output in circuits.

Given its role in modern electronics, the global demand for tantalum is massive.

Prior to the 2008 financial crisis, when tantalum production peaked, it was estimated that around 1,800 tonnes were produced each year. If that figure doesn’t take your breath away, then the scale of the journey it goes on before becoming pure, useable tantalum certainly should.

Mined as coltan, a compound of tantalum and niobium, the mineral is sent on an international journey that starts in African mines and moves through to smelters across the Balkans, Central Europe and Asia. The smelters extract and purify the tantalum, before sending it onwards to become the capacitors that are integrated into all our electronics.

This ‘coltan road’ wasn’t always the story of tantalum production. Until the early2000s, and to an extent today, much of the world’s tantalum was mined in Australia, Brazil and China. But as coltan reserves in nations such as DRC and Rwanda were opened and exploited, offering greater production at lower costs, production quickly shifted. As of 2014, the DRC and Rwanda accounted for almost 70% of global tantalum production. Those ‘lower costs’ were a boon to electronics companies and, by extension, to us as consumers.

But with the promise of larger profits and lower price-points was a dark trade-off: we became entangled in a web of corruption and destruction.

In 2003, the United Nations published a damning report. It found that as a result of social breakdown in the DRC stemming from the coup and subsequent conflict, warlords and militant groups were able to take advantage of the chaos to seize lands rich in coltan. Much of the Congolese landscape opened up, becoming coltan mines for which large groups of workers including farmers whose lands had been seized, children and prisoners-of-war

were drafted in to exploit the earth of the minerals. Instead of going to ordinary Congolese people and communities, the income from the mines was siphoned off by militants and despots to sustain their conflict and grip on power.

The resource-rich lands became flashpoints for bitter and violent conflict.

This came into sharp relief in 2000, when the popularity of the new Sony PlayStation 2 console caused demand for tantalum capacitors to spike. At one point, the price of coltan increased almost six-fold from $50 per pound to almost $300. To observers on the ground on the DRC, the price hike greatly raised the war’s stakes; as the UN reported, it directly led to “widespread destruction of agriculture and devastating social effects […] which in a number of instances were akin to slavery.”

Much effort has been made since then to put an end to the war. But despite the international mediation that has helped build a semblance of peace through the Congo, parts of the country remain embroiled in fighting. This has, in recent years, driven social entrepreneurs to try and take matters into their own hands.

For example, the Fairphone is a ‘conflictfree’ smartphone where all the metals used are traced to their source to ensure they are produced ethically. The ambition was to show that it is possible for technology companies to remove any reliance on conflict regions for metals like tantalum, taking away the fuel from the fires of war.

There are certainly signs that activism around conflict metals has paid off. Civic pressure helped compel the U.S., under former President Barack Obama, to introduce regulations forcing companies to audit their supply chains and disclose whether their products contained conflict metals, such that most major technology companies today now invest heavily into removing them from their products.

But behind the cheerful headlines lies a complicated reality. The sprawling,

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by Chun-Yin San multinational nature of the coltan road means proper audits are difficult. Throw in the possibility of corruption and the chaos of war, and it’s hard to know what the reality is.

The difficult truth is that there is no easy solution. Any strategy must be multidimensional, from giving the support needed by people in the DRC to resolve their differences to active civic engagement

in our own homelands and pressuring our governments and brands to reduce the ubiquity of conflict minerals in our lives.

Make no mistake, these steps will be difficult and there are no guarantees of success. The Obama regulations, for example, have been sharply criticized for pulling the rug out from under the feet of Congolese miners too quickly, worsening local poverty and creating incentives for militants to smuggle coltan out from the DRC to be passed off as ‘clean’ coltan. The scale of the challenge means it will take time to resolve, so that blood will continue to be shed. If conflictborne metals proliferate in our gadgets here in the West, and we continue to clamour blindly for them like we once did for PlayStation 2s, our responsibility in the conflict be sustained.

But, there is hope. With the benefit of hindsight, we can see that the work done over the last decade or so has led to substantial changes and concrete action.

The efforts made the U.S., however flawed in implementation, are a remarkable example of how advocacy can drive action. The Fairphone remains popular, and scrutinizing supply chains for conflict minerals is becoming a high priority for the world’s leading technology firms. There is also evidence that efforts in peace-making and supporting stable governance has paid off; more and more mines in the DRC are being certified as ‘conflict-free’, with higher safety standards and a better purpose.

Picture: Madeleine Finlay

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There is also work to be done by us, sitting so distant and shielded from our fellow earthlings. Go out there and tell somebody the tale of tantalum. Support a worthy cause that champions community-building and development of new non-mining industries in places like the DRC. Think twice before you buy your next gadget, and try to find out if the company you are supporting has met its ethical obligations.

Don’t forget, as you head out into the world, that its challenges could well start from the phone sitting in your hand.

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e owe oxygen a great deal. It allows us and the rest of the animal kingdom to respire, keeping our cells going, and it makes up most of our mass, in the form of water. We all know the perils of oxygen starvation; stroke and drowning survivors incur serious brain damage from the interruption to their oxygen supply.

Yet, as I was trawling through some of the world’s craziest records, one left me gaping at my screen in disbelief: it was the world record for longest underwater breath hold, broken last year by Spanish freediver Aleix Segura—a breathtaking (sorry) 24 minutes and three seconds. How did he manage this seemingly impossible feat, that would leave most of us completely brain dead?

The answer lies in the body’s extraordinary ability to adapt over time; Segura’s feat came about through a lifetime’s worth of training.

Surprisingly, the reflex to take a breath comes not from the lack of oxygen, but from the buildup of carbon dioxide, which causes the blood-stream to become more acidic. This stimulus relays the ‘please breathe now’ message to the brain. For freedivers like Segura, blood has been shown to acidify more slowly than in other people.

When we hold our breath, the sympathetic

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nervous system—the one controlling the ‘fight or flight’ response—causes the peripheral blood vessels to constrict, directing blood away from the extremities towards the vital organs. In trained divers, the reaction is quicker and they often slip into a form of meditation, literally slowing their heart down as well as mentally fighting the body’s urge to breathe. It also helps that their lung capacity is significantly greater than for us ordinary folk. Whereas the average capacity is four litres for women and six for men, acclaimed freediver Herbert Nitsch can hold an astonishing 14 litres of air!

Freedivers aren’t the only ones who are adapted to a life with limited oxygen. People who live at high-altitudes around the world such as Tibet, the Andes, and elevated parts of Ethiopia have modified their physiology in response to the extreme environment they’ve lived in for generations. ‘Mountain sickness’ is common among intrepid climbers, who experience dizziness, fatigue, breathlessness and vomiting, amongst other unpleasant symptoms, when traversing altitudes above 2,500 metres. This is from the lack of oxygen in the air, yet more than 140 million people are estimated to be living at these heights.

Whereas Andeans can carry more oxygen in their blood due to increased levels of haemoglobin, Tibetans have expanded

by Lizzie Riach blood vessels and increased breathing rate, allowing for more efficient oxygen delivery around the body. And as for Ethiopians? They have none of these obvious adaptations, yet still don’t suffer from altitude sickness. Physiologists are still scratching their heads as to how they do it.

On the other hand, for divers who go beyond recreational depths, or those using an air mix of elevated oxygen concentration (known as ‘Nitrox’, instead of the traditional compressed air), ‘oxygen toxicity’ poses a real danger. Oxygen becomes toxic when breathed in under high pressure, as free radicals are released much faster than can be eliminated in cells. This can affect the central nervous system, the eyes, or the lungs—and it can be extremely dangerous when diving deep, causing loss of vision, convulsions or complete loss of consciousness. Oxygen toxicity is usually avoided using depth tables and dive watches, which tell the divers when they are at risk, but it just goes to show there can be too much of a good thing!

Whether you want to dive to 50 metres or climb Mount Everest, be aware of the risks oxygen extremes can have on your body.

You can start practicing your breath holds now, but don’t hold your breath for hopes of beating that record.

Pictures: Kalyani Lodhia

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sodium22.99

by Sophie Protheroe

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t’s hard to resist the temptation of salt, even when you know how bad it is for you. But, perhaps the white stuff really is all that it is cracked up to be.

“Pass the salt, please?” Saltiness is one of the five basic human taste sensations, and sitting in kitchens around the world, sodium chloride, commonly known as table salt, is one of the oldest and most frequently used seasonings. But, salt is so much more than a condiment.

Although today we may take it for granted, salt was once prized by many ancient cultures. In the middle ages, it was referred to as ‘white gold’ because it was so expensive. Special ‘salt roads’ were built to trade it. Nations have even gone to war over it. All this fuss over a flavour may seem absurd, but in fact salt is necessary for life.

Sodium is an electrolyte that helps nerves and muscles to function correctly, as well as acting to regulate the water content of our bodies. All our cells contain solutes, such as salt, which must be balanced with the liquid surrounding the cell. If this liquid contains more solutes than the cell, the cell dehydrates. If the liquid has fewer solutes than the cell, water flows into the cell, rupturing the cell membrane.

This process of osmosis, when water moves through the cell membrane, is also intrinsic to the ancient art of food preservation by salting.

By soaking or rubbing meat with salt, water is drawn out of cells. Bacterial cells in the food then become dehydrated and die. When the meat is soaked in water, reverse osmosis makes it edible again. If done correctly, salted meat can last for years.

Although in the last hundred years or so, people have mainly turned to canning and artificial refrigeration for food preservation, salting is still used today. Corned beef and pastrami are made by soaking beef in a ten percent salt water brine for several weeks. Pickling combines the preservative qualities of both salt and acetic acid (vinegar), such as gherkins, which are made by soaking cucumbers in salt water brine for several days, rinsing them and then storing in vinegar.

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Of course, salt fermentation is not only a preservation technique but also a flavouring tool, making food delicious and nutritious.

During fermentation, a pool of larger, usually less flavourful molecules are transformed into tastier, smaller molecules, such as amino acids, esters and aromatic compounds. For example, lacto-fermentation is the process of adding salt brine to fresh vegetables. The brine triggers lactic bacteria, which are naturally found on the surface of the vegetables, into action. As the salty, oxygen-free environment stifles harmful bacteria and prevents decay, beneficial bacteria multiply and start eating the sugars in the vegetables, converting them into lactic acid and carbon dioxide. This produces the characteristic sour taste and fizzy bubbles of sauerkraut (fermented cabbage). Fermentation, unlike heating, also allows vegetables to retain their nutritious value.

However, we are constantly reminded that too much salt is bad for us. So what are the effects of salt preservation on our health? Evidence suggests that certain high-salt foods, such as saltpreserved meat, fish and vegetables, can cause stomach cancer because excess salt damages the lining of the stomach. Too much salt can also lead to kidney and cardiovascular diseases, such as high blood pressure, and the World Health Organisation recommends that adults should consume less than 5g of salt per day.

Yet, a diet comprised of predominantly grains and vegetables does require some additional salt, which might go some way to explaining our seemingly innate obsession with sodium chloride. But it isn’t just us. Animals in the wild go to extraordinary lengths to obtain salt. Alpine ibex have been seen scaling the near vertical wall of an Italian dam to reach salt, and moose are often spotted licking the salt from roads.

Sodium may be an everyday element, but it has extraordinary importance. Next time you reach for the salt shaker, take a moment to appreciate your little pot of white gold.

Picture: Judit Agui

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Picture: Annabel King www.isciencemag.co.uk

rubidium84.49 48 technetium98.91 37

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uclear gets a bad rap. For most people, the phrase might bring to mind a mushroom cloud, or Chernobyl. At best, it might conjure up an image of Homer Simpson. But why not a doctor? Since the 1950’s, radiation has been used in medicine to detect cancers in the human body. Every year around the world, over 40 million nuclear medicine procedures take place– more than half a million of these in the UK. Most will use the nuclear medicine Technetium-99m, which gives off gamma rays that can be picked up with specialised cameras.

The idea behind nuclear medical imaging is very similar to x-rays.

The biggest difference is that instead of a flash of radiation passing through the body from one side to another, a very small amount of radioactive material is injected into the bloodstream so that radiation coming from inside the body is picked up by the camera.

By targeting the radioactive ‘tracers’ to cells or structures we can build unique and valuable pictures.

“That’s the bread-and-butter clinical technique. We do somewhere between three and four thousand studies per year” says Professor Richard Underwood, who for the last 20 years has worked in one of the largest nuclear cardiology centres in Europe at the Royal Brompton Hospital. In the nuclear cardiology centre, doctors are finding new ways to apply nuclear medicine to study the heart.

“Traditional methods are good at showing the arteries, but not at showing how they work. How they work is more important in clinical decisions” says Professor Underwood.

Professor Underwood’s team images hearts during exercise and at rest using Technetium-99m attached to a tracer. “If there’s an area of muscle that’s dead, you don’t see any tracer uptake in stress or rest,” explains Professor Underwood. “It’s a way of looking at coronary function instead of coronary anatomy.” Coronary artery disease is the most common type of heart disease, the leading killer of people over 60 worldwide. Seeing blood flow can allow the team at Royal Brompton Hospital to target the treatment. But, as Professor Underwood points out, “as soon as you can measure something you can know much more about it.”

To measure blood flow, rather than just imaging it, Dr Georgia Keramida of Imperial College London is using another nuclear medicine called Rubidium-82 to make real-time images in the body. When Rubidium-82 decays, it doesn’t directly give out gamma rays like Technetium-99m. Instead, it gives out a positron– the antimatter version of an electron–which then annihilates with the first matter it finds to produce two gamma rays that are picked up by the camera.

“We then use computational modelling to see what is going into the heart. We can see if there is a problem in the arteries or reduced blood flow,” explains Dr Keramida, who hopes this technique will be able to save on unnecessary surgeries by enabling doctors to better see whether the blood flow is sufficient to be managed with drugs alone.

by Liz Killen

But matters of the heart are not the sole use of Rubidium; according to Dr Keramida “no one has really looked in the spleen”. But why is the spleen important? After a heart attack, white blood cells leave from the bone marrow and can accumulate there. These are thought to be an important healing ‘reserve tank’ for the heart, but they also cause increased inflammation and blood flow, too much of which may lead to a second heart attack.

As nuclear medicine techniques continue to improve, they are allowing doctors to avoid the risks of surgery in the most unstable patients. This is a huge step forward because, as Dr Keramida notes, “every intervention is dangerous”. But what about the radiation risk to the patient? While the radiation dose you receive is more than an x-ray, it is still normally less than you would get from taking a flight to LA, or living in Cornwall for a year, where the granite rock-bed is particularly radioactive. These are risks we are normally willing to take even when it’s not saving our life. Well… except maybe living in Cornwall for a year.

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Potassium39.10

by Catherine Webb

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hirty-eight year-old Kenneth Williams was a black man convicted of murdering two white people and causing the death of a third. On the day of his execution on April 16th 2017, he had been on death row for sixteen years. After being brought into the death chamber and strapped to a gurney, he gave a final statement—a rambling apology, which he was still giving when the controversial drug midazolam entered his bloodstream. He broke off and began to speak ‘in tongues’.

Three minutes later, eyewitnesses report that his body began to convulse and shake.

by firing squads and others by changing to a one drug protocol; essentially affording prisoners the same dignity given to dying pets—injecting them with an overdose of pentobarbital.

The State of Arizona has replaced the usual anaesthetic with the anti-anxiety drug midazolam. Midazolam is not approved by the FDA for use as an anaesthetic by itself and it has been involved in several botched executions. Eyewitnesses to Williams’ death report that he convulsed for around ten seconds and was soon after injected with the paralytic drug. He continued to breathe heavily and groan even after the injection, but these movements were dismissed by officials as “involuntary”.

The use of a paralytic is controversial because it ensures that convicts are unable to move when they are injected with potassium chloride; a drug which is so excruciatingly painful when injected in high concentrations it is banned from use in animals. In a disturbing post mortem study published in The Lancet, it was found that in 21 out of 43 prisoners, blood concentrations of anaesthetic were low enough for them to have fully experienced the pain as potassium chloride entered their bloodstream. The paralytic would have rendered them unable to speak, scream, or even move a muscle.

Picture: Maddy Dench

Williams’ is the latest execution to follow the triple lethal injection protocol, which uses potassium chloride alongside an anaesthetic and a paralytic. The protocol was invented in 1977 as a more sanitised alternative to the electric chair or the gas chamber. However, controversy has swirled around the method over the past few years, with pharmaceutical companies backing away from supplying anaesthetics to executioners. Different states have responded to this lack of anaesthetics in a variety of ways; some by reverting to death

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Potassium chloride works by interrupting the electrical signals that control the heart’s contractions. The heartbeat is controlled at the top of the heart in the sinoatrial node, a group of cells that are also sometimes called the pacemaker. The pacemaker moves positive ions, including potassium, in and out of its cells, which creates a fluctuating electrical signal. This signal tells the heart to alternately contract and relax, creating the beat that pumps blood around the body.

When injected in high doses, potassium chloride causes death by flooding the heart with potassium ions. This reverses the usual concentration gradient and makes it impossible for the pacemaker to move positive ions back and forth in its usual

way, so the heart stops beating. The use of potassium chloride in the euthanasia of domestic animals is condemned by the American Veterinary Medical Association as the pain associated with injecting it is considered too extreme. However, over the last forty years Williams is just one in a line of 1,220 people who have been injected with a lethal dose.

The origin of the three drug protocol is an unlikely one. It was thought up in 1977

by Oklahoma Medical Examiner, Dr Jay Chapman, but was never intended to be more than a quick fix to quell growing public unease with the use of the electric chair and gas chamber. Part of the current controversy surrounding death by lethal injection is that health professionals are not present to administer the drugs or deal with any complications (their professional ethical code forbids it). Chapman has been quoted as saying that when he wrote the law he never imagined anyone who was not qualified to administer these drugs would be doing it. The lack of health professionals present means incorrect dosages, faulty catheter insertion and kinked intravenous lines are all more likely. There have even been cases, such as that of Charles Warner in 2016, where the wrong drugs were administered. Warner spent 43 minutes writhing in agony before he died, and his last words were “my body is on fire”.

In Williams’ case, death took the usual 13 minutes. At 23:05 local time his heart stopped beating and his body was removed.

Williams’ crimes were considerable. He was convicted of murdering Dominique Hurd and given a life sentence. Only a month later, he escaped from a high security prison, killing one person and indirectly causing the death of another in a traffic accident. No one would say that Williams was innocent.

However, if killing is wrong, killing by the machinery of the state must also be wrong.

The use of a three drug protocol, which may cause and disguise incredible pain, pain that we all agree should not even be inflicted on animals, must be doubly so.

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Paper courtesy of the Imperial College Archives For answers please visit the I, Science website. www.isciencemag.co.uk

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