Nuclear Power: What If?

Renewables such as wind power are at the centre of efforts to reduce carbon emmissions

I think nearly all of us are aware of the urgent need to reduce carbon emissions and ideally create a carbon-neutral society. There’s a major focus on renewable energy such as wind, tidal, hydroelectric, solar and geothermal. I’m making my own small contribution through solar panels on my house. However, when it comes to talking about reducing carbon emissions, there’s an elephant in the room. A source of electricity that is not renewable but can generate large amounts of electricity with negligible carbon emissions: nuclear power.

Disasters such as Fukushima mean that nuclear power is widely rejected as a low-carbon option

There are obvious and understandable reasons why discussions on reducing emissions tend to ignore the nuclear option. Windscale, Three Mile Island, Chernobyl and Fukushima are four of them. The management of nuclear waste which may remain radioactive for hundreds of thousands of years is another; as is the safe decommissioning of reactors at the end of their working life. But it didn’t have to be this way.

In the late 1940s, when research was going on into the potential use of nuclear energy for generating electricity, two possible fuels were investigated: thorium and uranium. When bombarded with neutrons, thorium is converted into uranium-232, which will then undergo nuclear fission, releasing heat. This can then be used to create high pressure steam to drive turbines. The other fuel, uranium-235, also undergoes nuclear fission to release heat.

Thorium is abundant in the Earth’s crust and is often a waste product of mining for other metals

It was clear from the beginning that thorium had some very significant advantages over uranium as a fuel. Firstly, thorium is much more abundant than uranium, and it is a lot easier and safer to mine and process. In fact, massive amounts of thorium are created as a waste product from mining other metals. In addition, nearly all thorium is ‘fertile’ – meaning it can be used as fuel. Uranium, by contrast, is mostly the non-fertile isotope uranium-238; only 0.7% is uranium-235, which can undergo nuclear fission. This means that thorium does not require expensive fuel enrichment processes.

Another benefit is that a thorium reactor produces much less radioactive waste than a uranium reactor; up to 1000 times less, in fact. In addition, those small amounts of waste products remain radioactive for between 1 and 100 years; by contrast, the waste products from uranium remain radioactive for tens or even hundreds of thousand years. The decommissioning of thorium plants is also safer and easier.

A meltdown, such as that which occurred at Chernobyl, is impossible with a thorium reactor

Thorium reactors are much, much safer than uranium reactors. In fact, they are literally melt-down proof. The reason for this is that they use a liquid fuel – molten thorium fluoride. In the bottom of a thorium reactor is a plug which will melt if the temperature of the fuel exceeds a set limit. The fuel will then be drained into a tank for safe storage. Since thorium must be bombarded with neutrons to undergo nuclear fission, once removed from the reactor, nuclear fission ceases and the fuel is safe.

By contrast, uranium reactors use a solid fuel and rely on control rods which can be lowered into the reactor to absorb neutrons and slow down or stop nuclear fission. In addition, any failure in the cooling system can lead to a meltdown. If the cooling system of a thorium reactor fails, the plug described in the previous paragraph will melt and the fuel will drain from the reactor.

Thorium reactors are also highly efficient. It is estimated that one ton of thorium can generate the same amount of electricity as 200 tons of uranium or 3,500,500 tons of coal.

Liquid thorium fluoride is highly corrosive

There are some disadvantages. One is the cost of processing thorium ore into thorium fluoride fuel; however, uranium also requires extensive processing and enrichment before it can be used in a reactor. another disadvantage is that the molten thorium fluoride fuel is highly corrosive. However, it would be perfectly feasible to develop corrosion-resistant materials that could be used to line the reactor. There are a few other potential problems which I won’t go into as the science is quite complex; all of these can be solved if there is sufficient investment into thorium technology.

Between 1965 and 1969, an experimental thorium reactor was successfully developed and tested at the Oak Ridge National Laboratory in the USA. Nevertheless, in 1973 the US government made the decision to abandon thorium technology in favour of uranium. Other governments such as the UK and France had already made the decision in favour of uranium.

The experimental thorium reactor at Oak Ridge
The need to manufacture plutonium for nuclear weapons was a major factor in the decision to opt for uranium.

So, why did governments abandon a cheap, clean and safe fuel in favour of one that is more dangerous and generates more waste? The official reason was that uranium reactors are supposedly more efficient. The true answer lies in what is either thorium’s biggest advantage or its biggest disadvantage, depending on your point of view. Quite simply, a thorium reactor does not produce plutonium, which is needed to create nuclear weapons. In the climate of the Cold War, governments made the choice to go with the fuel that produced the plutonium they needed for their nuclear weapons programmes. In the late 1960s and early 70s, Alvin Weinberg, the director of Oak Ridge, argued passionately for the adoption of thorium as the fuel for nuclear power. His refusal to abandon what he considered to be a safer, cleaner option in favour of one with weapons applications eventually cost him his job.

Many countries continue to maintain a nuclear deterrent such as the UK’s Trident submarines

So, what is the future? Many countries, including the USA and UK, are reluctant to provide the funding that is needed to develop thorium technology into a viable method of generating electricity. A notable exception is India, which has abundant supplies of thorium and is aiming to generate 30% of its electricity from thorium by 2050. In addition, despite the ending of the Cold War, many countries including the UK continue to maintain a nuclear deterrent. This means that the demand for plutonium is unlikely to end any time soon.

If Irene and Frederic Joliot-Curie had lived longer, they might well have been advocates for thorium power

A final note. Two of the most influential scientists in the development of nuclear power were Irene and Frederic Joliot-Curie, subjects of one of my previous posts. They oversaw the development of France’s first nuclear power station. Both died prematurely from radiation-related illnesses; Irene in 1956 and Frederic in 1958, when the nuclear program was in its infancy. As ardent pacifists, it is possible, even likely, that they would have championed the development of thorium as a nuclear fuel. Had they lived longer, would we now have a safe source of low-carbon nuclear energy?

Back again!

Hi all, it’s been a while but I am back in action. When I started this blog the intention was for it to be a science blog that looked at aspects of science that are overlooked, quirky, controversial etc. With the pandemic it rapidly morphed into more of a COVID-19 blog. Now that things have (hopefully) settled down a bit, I am going to try and return to the original intention. I will still post about COVID but it won’t dominate the way it has in the past.

Watch this space,


COVID Vaccine FAQs

Hi everyone. As you know, I had my first Astra Zeneca jab on March 23rd, appropriately enough the 1-year anniversary of lockdown #1.  I will be very relieved to get my second one on 8th June – I’m counting the days!  In this post I am hoping to answer some of the most common questions and debunk some common myths about the vaccine. 

How does the vaccine work?

All vaccines work on the same basic principle.  Something is introduced into the body that fools your immune system into thinking you have a disease, so it produces antibodies and other cells to fight that disease.  If you are then infected with the actual disease, your immune system ‘remembers’ how to produce those antibodies.  This means that your immune system will fight off the disease without you developing symptoms or becoming infectious.

The COVID vaccine contains a small segment of the virus’ RNA containing the instructions to make the spike protein, which is found on the surface of the virus.  When you are vaccinated, your cells will take up this RNA and use it to manufacture the spike protein; this provokes your immune system into producing antibodies and white blood cells to destroy it.  If you are then exposed to the actual virus, your body will be able to produce antibodies and destroy it very quickly.

What is the difference between the various vaccines?

All the vaccines contain the RNA for the spike protein, encased in a capsule.  When you receive the vaccine, the capsule breaks down inside the body and releases the RNA.  Different vaccines use different capsules.  The Pfizer and Moderna vaccines both use a lipid (fat) capsule; Astra Zeneca (AZ) uses a deactivated virus capsule.

Is the AZ vaccine less effective than the others?

No.  Apparent differences in the effectiveness of the vaccines are basically due to differences in the way the data has been processed and presented in the scientific literature; and the way the data has then been represented – or misrepresented – in the media. 

All three of the currently licensed vaccines in the UK have very similar effectiveness.  Data published by Public Health England at the end of March has shown that all three vaccines provide on average 60 % protection after the first dose and over 85% after the second.  To put that in context, the effectiveness of the seasonal flu vaccine is between 55 and 60 %.

It’s also worth noting that the higher the uptake of a vaccine, the more effective it is – this is because if the majority of the population is vaccinated, the probability that the virus mutates and becomes vaccine resistant is much lower.   

How have the vaccines been developed?

The various vaccines have been developed through collaborations between researchers who develop and test the vaccine, and pharmaceutical companies who develop and implement manufacturing processes. 

The big advantage of these collaborations is that by the time each vaccine had been developed and tested by researchers, the pharmaceutical companies had the manufacturing processes ready to go.  This dramatically reduced the time needed to get the vaccines into clinical use.

Is this untried technology that has been rushed into use too quickly?

Definitely not.  Research and development into RNA vaccines has been going on for over 30 years.  Several companies including Pfizer were already actively researching RNA vaccines for flu; however, without the pandemic, it would have been several more years before any RNA vaccines made it into clinical use.  The pandemic has accelerated the process because vast amounts of funding were made available. 

Is the vaccine safe?

The COVID vaccine is very safe indeed.   Traditional vaccines use either a dead or weakened version of the organism that causes the disease.  There is a small but significant segment of the population that cannot have these vaccines, including the elderly and people who are immunosuppressed.

Because the COVID vaccine uses RNA rather than dead or weakened virus, it can be given to the majority of the population including the very elderly and those who are immunosuppressed.

What side-effects might I get?

The most common side-effects are some soreness at the injection site, and mild flu-like symptoms.  Both resolve within a couple of days.  Many people, including myself, have experienced a metallic taste in the mouth for approximately 24 hours after the AZ vaccine. 

When you have the vaccine, you will be given a leaflet which includes a list of side-effects.  If you do get side effects, however mild, it is worth reporting them using the MHRA’s yellow card scheme:

Will I test positive after the vaccine?

The vaccine will not cause a positive test.  The vaccine causes your body to make the spike protein; both the lateral flow and PCR tests detect other parts of the virus structure.  If you have had the vaccine and get a positive result afterwards, you should follow the normal procedure for self-isolating.

What about blood clots?

The media has made much of the risk of a rare form of blood of blood clot associated with the Astra Zeneca vaccine.  However, the actual figures tell a different story.  As of March 31st, there have been 79 instances of this rare type of blood clot (14 fatalities) following the first dose of the AZ vaccine; this is out of 20.2 million doses.  Analysis has found that the risk is slightly higher among the under-30s; as a precaution, the AZ vaccine is no longer being offered to this age group.

To put these figures in context, according to Department of Transport statistics, in 2020 there were 24,470 people killed or seriously injured in road accidents – an average of 67 per day.  Personally, I was quite happy to have my first dose of AZ vaccine and will be even happier when I’ve had my second.

Will the virus’ RNA remain in my body forever?

One piece of disinformation that is doing the rounds on social media is that once you are vaccinated, the virus’ RNA will remain in your body forever; and that you will effectively have become genetically modified.  This is not the case.  RNA is a short-lived molecule which is broken down once it has served its purpose.  Once the RNA from the vaccine has been used to make the spike protein, it will be broken down and eliminated from your body.  The same thing will happen to the spike protein; your immune system will destroy it and it will be eliminated from your body. 

What if the virus mutates?

A big advantage of RNA vaccines is that if variants emerge that are resistant to the existing vaccines, a new vaccine can be created in a matter of a few weeks.  This is because all that needs to be done is to isolate the RNA for the new spike protein, then insert it into the existing capsule.  Manufacturing processes do not need to be altered, and much less safety testing is required.

Now that RNA vaccines are a reality, it possible that in the next few years they will replace traditional vaccines for other rapidly mutating viruses such as influenza.

Will I need a jab every year?

This is still being debated but it is likely that for the next few years at least, an annual COVID vaccine will be needed.  There are two reasons for this.  Firstly, we do not yet know how long the immunity provided by the vaccine lasts; a yearly booster is therefore a sensible precaution.  Secondly, it may be necessary to vaccinate annually due to changes to the virus that make previous vaccines ineffective.

Why is the vaccine not available to under-18s?

At present, clinical trials for vaccines have only been carried out in adults.  Children and adolescents are physiologically very different to adults.  Because of this, dedicated clinical trials must be carried out in children before any vaccine can be licensed for the under 18s. 

Now that the safety of the various vaccines in adults has been well established, small-scale clinical trials are underway in children and adolescents for both the Pfizer and Moderna vaccines. A trial of the AZ vaccine has been suspended as a precaution following the decision not to use it for those under 30.

Saviour of the World, or War criminal? The enigma of Fritz Haber

Haber’s life was the tragedy of the German Jew – the tragedy of unrequited love – Albert Einstein

Almost exactly 106 years ago, on the afternoon of April 22nd 1915, things were fairly quiet on the Northern edge of the Ypres Salient between Gravenstafel and Langemark.  Possibly too quiet, as subsequent events would demonstrate.  But for the French Territorial and Colonial troops in the trenches, there was nothing to indicate the horror that was about to be unleashed.

As the afternoon drew on, a slight breeze began to blow from the direction of the German lines.  At approximately 5pm, a strange greenish-grey mist was observed moving towards the Allied lines from the German trenches.  It was chlorine gas, and when it reached the French trenches, all hell broke loose.  Men died in agony as the chlorine reacted with moisture in the linings of their airways to form corrosive hydrochloric acid.  The French troops broke and ran, leaving 4 miles of the front line completely undefended.  The Germans could have broken through to Ypres and on to the Channel Ports; however, two things saved the day for the Allies. 

The first was that the effectiveness of the gas took even the Germans by surprise, and they simply did not have enough troops to exploit the breakthrough.  The second was the almost unbelievable courage of the Canadian troops on the Southern flank of the breakthrough. They moved into the trenches the French had abandoned and fought off multiple gas attacks. In two days, the Allies lost about 5000 killed and 15000 wounded.  It was the first large-scale use of a lethal, asphyxiating gas in warfare, and set the scene for 3 years of horror as both sides raced to develop ever more effective chemical weapons.

The man behind it all was a quiet, bespectacled, middle-aged German army lieutenant named Fritz Haber, who would become one of the most controversial scientists of the 20th century.

Before the War, Haber had been a Professor of chemistry at the University of Karlsruhe, and in 1911 had become the first director of the new Kaiser Wilhelm Institute in Berlin.  His most important work, however, was carried out while he was at Karlsruhe.

Look at a graph of world population, like the one shown below, and you will see that until about 1800 ACE, population growth was very slow.  From 1800 on, the world’s population began to grow with increasing rapidity, as improvements in food production, medical care and living conditions began to reduce mortality rates.  As the end of the 19th century approached, the world’s population was heading towards unsustainable levels.  Quite simply, the human population was about to exceed the Earth’s capacity to produce food.

The problem was a shortage of nitrogen.  This element is essential for plant growth, and without plants and their ability to photosynthesise, there is no food.  But nitrogen is one of the most abundant elements on Earth, so how could there be a shortage?  The answer is that the bulk of the Earth’s nitrogen is in the atmosphere, where it cannot directly be used by plants.  Plants require water-soluble nitrates, which can be taken up from the soil by their roots.  

The nitrogen cycle

In the ordinary way of things, this is taken care of by Mother Nature.  Bacteria in the soil and in the root nodules of leguminous plants ‘fix’ nitrogen into ammonia, and a small amount of atmospheric nitrogen is also ‘fixed’ by lightning. Other bacteria and fungi convert nitrogen from dead plant and animal matter into ammonia; a third group of bacteria then convert the ammonia into nitrates.  This is known as the nitrogen cycle. By the late 19th century, these natural nitrogen-fixing processes could no longer produce enough nitrates to meet the increasing need for food crops.  A cull of the world’s population by means of a catastrophic world-wide famine was imminent, unless a way could be found of artificially fixing atmospheric nitrogen. 

Apparatus used by Haber and Le Rossignol

Enter Fritz Haber and his assistant, Robert Le Rossignol, who in the summer of 1909 succesfully produced ammonia by reacting hydrogen and nitrogen gases at high temperature and pressure, using an iron catalyst. Once you have ammonia, it is then relatively straightforward to convert it into nitrates for fertilisers.

The first operational ammonia plant at Oppau in Germany

Carl Bosch of the BASF company scaled-up the process to industrial level, with the first operational ammonia plant opening in 1913 at Oppau.  Now known as the Haber-Bosch process, this was one of the biggest breakthroughs industrial chemistry has ever seen, and paved the way for the large-scale manufacture of nitrate fertilisers, meaning that food production could continue to increase and meet the needs of the expanding population.

Guano from seabird colonies in Peru were a major source of nitrates. Bloomberg photo by Vera A. Lentz

By a (not so?) happy coincidence, Haber and Bosch’s work also meant that if war broke out, Germany would be able to manufacture nitrates to make explosives. Prior to the invention of the Haber-Bosch process, the main source of nitrates for both fertilisers and explosives was guano. Yes, you did read that right, guano as in bird poo. Guano is a rich source of nitrates, and the best sources of guano in terms of both quality and quantity could be found in South America, particularly the Chincha Islands in Peru, where millions of seabirds create mountains of guano up to 150 feet high. In the 19th century, the importation of guano by sea was big business. In the event of a war, it was possible, even likely, that a Royal Navy blockade would be able to prevent Germany from importing guano. The Haber-Bosch process meant that in this event, Germany’s munitions factories could continue to churn out shells and bullets. Despite this, the invention of ammonia synthesis was, overall, something that benefited humankind. So how did Haber go from that to chemical warfare?

Fritz Haber was intensely patriotic.  Part of this was due to his having been born into a Jewish family. In the early 20th century, antisemitism in Germany was nowhere near as prevalent as it would become in the Nazi era. However, it was significant enough for Haber to feel that despite his having converted to Christianity, he needed to prove his patriotism and devotion to the Fatherland. Haber was enthusiastic about the war, and was one of 93 German intellectuals to sign a proclamation which enthusiastically endorsed the declaration of war.

Haber (pointing) with gas troops and equipment

In addition to his patriotism, Haber had two areas of expertise that made him the ideal person to lead Germany’s efforts to develop poisonous gas as a weapon. The first was in electrochemistry, which is crucial in the manufacture of chlorine gas. The second was in working with gases under pressure, which enabled him to develop equipment with which to deliver the gas, and meant that throughout the war, German equipment was superior to anything used by the allies.

For the duration of the War, Haber led the German efforts to develop both chemical weapons and defences such as gas masks. The result was that Germany was always one step ahead of the allies in both. It is estimated that there were about 1.3 million casualties as a result of gas, with approximately 90,000 fatalities – relatively trivial in relation to the overall numbers of casualties. But gas was, first and foremost, a weapon of terror; its aim was to disrupt, damage morale and consume resources treating the wounded. During the first gas attack at Second Ypres, many of the troops who broke and ran did so out of sheer terror, having seen the effects of the gas on others. Mustard gas in particular was designed to maim and terrorise rather than kill.

Clara Haber committed suicide shortly after the gas attack at Ypres

Haber’s involvement in chemical warfare was to cost him dearly. On 2nd May 1915, his wife Clara committed suicide, shooting herself through the heart with Haber’s own army revolver while her husband was celebrating his promotion to captain. A dedicated pacifist and a talented chemist in her own right, her husband’s involvement in the war is thought to have been a major factor in Clara’s suicide.

After the war, Haber came in for a great deal of criticism from the scientific community. He was awarded the 1918 Nobel Prize for Chemistry for his work on ammonia synthesis, and this was controversial to put it mildly. Many eminent scientists boycotted the award ceremony in 1919, and it is said that Sir Ernest Rutherford refused to shake Haber’s hand.

In the post-war years, Haber continued as Director of the Kaiser Wilhelm Institute, where he led Germany’s secret efforts to develop new chemical weapons, in direct contravention of the Treaty of Versailles. But dark clouds were gathering on the horizon. When Hitler became Chancellor in 1933, he immediately began to target Jewish scientists. Haber was personally targeted, with Hitler claiming that his appointment as director of the Institute was a result of his being the nephew of a Jewish profiteer (which he wasn’t). This came as a shock to Haber, who had thought that his service in WW1 and his conversion to Christianity would be enough to protect him. Although Haber could not legally be dismissed, the Nazis made his position untenable and he resigned in October 1933. He left Germany and after a brief spell in England, in January 1934 he set out to take up a new job in Palestine. But he never reached his destination. Events had taken a severe toll on Haber’s health and on 29th January 1934 he died of heart failure while breaking his journey in Switzerland.

Zyklon B, used at Auschwitz-Birkenau and other death camps during the holocaust.

There is a final hideous twist to the story of Fritz Haber, the scientist hounded out of Nazi Germany because of his Jewish roots. Between the wars, the research Haber was overseeing at the Kaiser Wilhelm Institute included the development of new pesticides and fumigants. This included the development of a highly effective class of fumigants which consisted of hydrogen cyanide gas adsorbed onto diatomaceous earths. When exposed to air, the lethal gas was released. These agents were given the name ‘Zyklons’ and included Zyklon B, which would be used in the murder of 1.1 million people in the Holocaust. Among those who would perish in the gas chambers were several members of Fritz Haber’s own extended family.

The costliest death of WW1? The tragedy of Henry Moseley

In view of what he [Moseley] still have accomplished … his death might well have been the most costly single death of the War to mankind generally – Isaac Asimov

The First World War was one of the most deadly and wasteful conflicts in human history. An entire generation torn apart, and many brilliant minds lost. Who knows what Wilfred Owen might have gone on to achieve, had he not been killed in action almost exactly a week before the armistice? And he was just one among many. But while most people have heard of Wilfred Owen, many of you reading this may never have heard of Henry Gwyn Jeffreys Moseley.

Henry Moseley, known to his friends as Harry, was born in 1887. His father was a professor of anatomy and physiology at the University of Oxford, and his mother, herself the daughter of an eminent biologist, went on to become the British women’s chess champion in 1913. So it’s hardly surprising that Harry excelled at science, winning the physics and chemistry prizes at Eton where he had been awarded a King’s scholarship. What is perhaps more surprising is that Harry did not follow the family tradition and go into biology – his interests lay in chemistry and physics, and particularly in the structure of the atom.

After graduating from Trinity College, Oxford, Harry Moseley went to Manchester to work under Sir Ernest Rutherford, one of the most eminent scientists of the time, who was studying radioactivity. In 1913 Rutherford offered Harry a fellowship, which he declined, preferring to return to Oxford where he could work on his own independent research. In particular he wanted to work on solving the problem of how to measure atomic number.

The periodic table of the elements is one of the most powerful tools known to science, and one which we now take for granted. Russian chemist Dmitry Mendeleev created the first true periodic table by putting the elements in order of mass. He noticed that this resulted in certain pairs of elements (for example, iodine and tellurium) being ‘back-to-front’ based on their properties, and incorrectly assumed that this was due to errors in calculating their atomic masses.

Mendeleev assigned each element an atomic number based on its position in the periodic table; however, in cases such as iodine and tellurium, this was semi-arbitrary (science-speak for ‘educated guess’) and based on chemical properties. Moseley would be the one to prove that these elements were placed correctly, based on atomic structure. He would also be the first to find experimental evidence to support the existence of atomic numbers – a concept that until then had been theoretical only.

Moseley’s speciality was X-rays. Not medical X-rays, but the study of how X-rays relate to atomic structure. I won’t go into too much technical detail, but basically what he did was to shine a beam of high energy electrons onto different metals in a vacuum. As you can see on the left, this causes the metal to emit X-rays at an angle to the electron beam. This is called diffraction.

Moseley holding one of his X-=ray tubes

By using a detector, Moseley could measure the angles at which the X-rays were emitted. By applying Bragg’s Law (a mathematical formula relating angle and wavelength), he could then calculate the wavelengths of X-rays given off by each metal. So far, so what? The important breakthrough came when Moseley compared wavelengths to the position of each metal in the periodic table, and found that there was a direct mathematical relationship – now known as Moseley’s Law. Finally, atomic number could be proved experimentally. Amongst other things, Moseley was able to show that Mendeleev’s positioning of problematic elements such as iodine and tellurium was correct. He was also able to solve the problem of where to put the lanthanides – in the periodic table, that is – which had been occupying chemists for years (we don’t get out much…).

Royal Engineers manning a communication post where orders would be relayed by telephone or wireless

In August 1914, Harry Moseley’s work was rudely interrupted by the outbreak of the First World War. In the rush of patriotism following the declaration of war, young men flocked in their thousands to enlist. Despite the efforts of his family and friends to dissuade him, Moseley felt it his patriotic duty to join them, and enlisted in the Royal Engineers. In April 1915 he was sent to Gallipoli where he served as a communications officer. On 10th August 1915, at the age of 27, one of the most brilliant young scientists of his generation was killed in action – shot by a Turkish sniper whilst relaying an order over the telephone.

The consequences to science of the loss of Moseley were significant, and his death provoked an outcry within the scientific community. Robert Millikan, who would go on to win the Nobel Prize for Physics in 1923, wrote that,

“Had the European War had no other result than the snuffing out of this young life, that alone would make it one of the most hideous and most irreparable crimes in history.”

Many scientists, including Sir Ernest Rutherford, speculated that had he lived, Moseley would certainly have been awarded a Nobel Prize for his work on atomic structure. Moseley did leave one important legacy though. His death in the First World War was a significant factor in ensuring that in the Second World War, scientific research would be designated as a reserved occupation, ensuring that scientists who would otherwise be eligible for military service were unable to enlist. Just one of many scientists whose life may well have been saved by this was Alan Turing, who made crucial discoveries in the field of computer science and played a key role in cracking the Enigma code.

My Vaccine Experience

So, as planned, I had my first injection of the Astra-Zeneca COVID vaccine on March 23rd and it couldn’t have gone more smoothly. I thought I’d post about my experience to reassure people about the vaccine in general and AZ in particular. And to let people in the UK know what to expect when you attend a mass vaccination centre.

The first thing you should be aware of is that you won’t be allowed to enter the building until five minutes before your appointment. Not a problem if you are driving and can wait in the car, but worth bearing in mind if you are going on foot. When you go in you will be asked to sanitise your hands and wear a face mask; if you are exempt, you will be given a plastic visor to wear.

A receptionist will check your details and give you your NHS number if you don’t know it. You will then be directed where to go next. The mass vaccination centre I attended was very much a multi agency affair; as well as NHS staff there were personnel from the Fire Service, Army, RAF and St John Ambulance.

When it’s your turn you will be called forward to sit at a table where you will be asked a series of questions to determine your eligibility and suitability for the vaccine. This is a safety check where they will ask about things like allergies, underlying medical conditions and whether you are taking certain medications. When this is done, they will tell you which vaccine you are getting and ask for your verbal consent. They will also give you a detailed information sheet and will answer any questions you have.

Once that is done, the person processing you will call a medic over who will give you the actual injection. Don’t be surprised if this is a member of the Armed Forces. I was processed by a RAF medic and given the injection by an Army medic. You can be reassured that they will have had the same level of training as NHS staff.

After the injection you will be given a card which you need to bring to your next appointment. For me, getting through the next 12 weeks without losing it, or forgetting where I’ve stashed it so I won’t lose it, is possibly the most stressful part of the process! You also get a sticker but sadly no lollipop – that’s NHS cutbacks for you!

If you have driven to the vaccination centre, you will then be asked to wait in a waiting area for 15 minutes. The waiting area is socially distanced and is monitored by someone trained to spot any signs of anaphylaxis. Make sure you take a book or tablet or something – I didn’t and had to resort to reading the BBC news on my very small iPhone SE!

So, what about side-effects? There has been a lot of adverse publicity about the AZ vaccine and particularly its safety in younger age groups. Well, I am 48 and had absolutely no concerns about having the AZ vaccine. About 3 hours after the vaccine I started feeling very tired and generally a bit off-colour. I also developed a strong metallic taste in my mouth. Since this is a COVID symptom and is not yet on the official list of AZ side-effects I had to leave work, get a PCR and self-isolate until the result came in.

The PCR result was negative and the symptoms disappeared almost exactly 24-hours after they first appeared. I had a sore arm for a few days but no worse than the flu vaccine. And nothing compared with the pneumococcus vaccine – anyone reading this who’s had it will know exactly what I mean!

I mentioned that altered taste is not yet officially a side-effect of the AZ vaccine, although I know a number of other people who experienced it. This is why it’s really important that people use the Medicines and Healthcare products Regulatory Agency’s Yellow Card system to report any side effects. The Yellow Card system is used to collect data on all medications, but they have a dedicated site for COVID medications and vaccines. You can access it using the link at the end of this post. Note, this only applies to the UK but other agencies such as the FDA in the US and the EMA in Europe have similar reporting systems.

All in all, other than the lack of lollipops, my experience of getting the first jab was entirely positive. I look forward to getting my second one, not least because then I can stop worrying about where I put that darned card…

Link to yellow card:

What is mRNA, and how does it work?

I am very, very happy and excited today! The reason? I have a date booked for my COVID vaccine. 23rd of March is the day (coincidentally, the anniversary of the first UK lockdown), and it can’t come soon enough for me. The speed at which the various COVID vaccines have been developed, tested and approved for clinical use is impressive and means that we should, finally, have the end of this pandemic in sight. Unfortunately though, the anti-vaxxers are coming out of the woodwork in droves, and there are all sorts of myths and misinformation being pedalled on social media.

This is the first in a series of posts I am planning about the COVID vaccines. Many of the vaccines, including Pfizer and Astra Zeneca, are mRNA vaccines. So, I am going to start with the basics: what mRNA is and how it works.

mRNA is one of a group of biological molecules called the nucleic acids. These are DNA, and various types of RNA. Nucleic acids consist of molecules called nucleotides, joined together in long chains. Each nuclotide consists of a sugar, a phosphate group and a nitrogenous base. The sugar and phosphate make up the backbone of the chain, and the nitrogenous bases make up the genetic code.

A DNA molecule consists of two single strands, which combine to form the familiar double-helix.

DNA stands for deoxyribonucleic acid. It is a stable, information storage molecule that contains the ‘instructions’ for making proteins. In humans, all the instructions (genes) for every protein the body needs to make are stored on 46 molecules of DNA, called chromosomes. These make up the genome, and are found in the nucleus of every cell. DNA nucleotides consist of a phosphate group, the sugar deoxyribose, and one of four bases: adenine (A), thymine (T), guanine (G) and cytosine (C).

mRNA is single-stranded and much shorter than DNA.

DNA never leaves the nucleus of a cell. For one thing, it’s too big and cumbersome. For another, it needs to be protected against damages. So, when a cell needs to make a particular protein, the gene for that protein is copied in the form of messenger RNA or mRNA. Ribonucleic acid (RNA) differs from DNA because it is a short-term molecule used for the transfer and processing of genetic information. There are many types of RNA, of which mRNA is just one. RNA nucleotides consist of a phosphate group and the sugar ribose. Three of the nitrogenous bases are the same as those in DNA: A, G and C. However, thymine (T) is replaced with uracil (U).

When a cell needs to make a particular protein, an enzyme called RNA polymerase copies the gene in the form of a molecule of mRNA; this is called transcription. The mRNA leaves the nucleus of the cell and enters the cytoplasm, where it binds to a structure called a ribosome; the ribosome then assembles the protein. This is called translation.

A virus like COVID-19 cannot manufacture its own proteins. Instead, it must infect a cell and take over its organelles.

Viruses like COVID-19 cannot carry out transcription and translation, since they do not have ribosomes and various other things that are needed. Viruses carry their genetic material in the form of DNA or RNA – RNA in the case of COVID-19. When COVID-19 infects a cell, the virus capsule breaks open, releasing the RNA into the cell’s cytoplasm. Ribosomes in the cell will bind to the viral RNA in the same way they bind to mRNA, and will manufacture the necessary proteins for producing new viruses.

Lateral flow vs PCR: how do they work?

Lateral Flow Test

There has been some controversy in England this week surrounding the mass testing of pupils for COVID-19 as they return to school. The problem is that the government seems to be contradicting itself regarding the relative reliabilities of the lateral flow test (LFT) and the polymerase chain reaction test (PCR). If a student has a positive LFT from a test done at home, and they subsequently have a negative PCR test, they can return to school. If a student has a positive LFT from a test done at school, then they must self-isolate for ten days even if a subsequent PCR is negative. In this post I am going to explain how the two tests work, and why a positive LFT is always followed up by PCR.

When a new LFT for detecting small amounts of EPO was developed, Lance Armstrong decided to confess.

LFT or, to give it its full title, lateral flow immunoassay, is not new; in fact, it’s been around for years. LFT is a quick, cheap and simple method used to detect specific analytes or biomarkers. Prior to COVID, the most common use of LFT was in pregnancy testing. Lateral flow testing is also used in drug testing, for example in testing athletes for performance enhancing drugs such as EPO. In fact, it was the development of LFTs that could test for EPO that led Lance Armstrong to confess to having used it in his 7 Tour de France wins; he knew that when stored urine samples were tested using the new method, the game would be up.

LFTs are used to check for substances or biomarkers in bodily fluids or swabs. Urine is commonly used in drug testing, while swabs are used to test for pathogens. LFTs use two lines: one is a control line, which confirms that the test is working; the other is the test line. The lines are made up of labels; these are nanoparticles of substances which will bind to the substance being detected and cause a visible line to appear. Labels include nano-beads of coloured polystyrene or latex (a nano-bead is a bead that is around one millionth of a millimetre in diameter!).

This LFT is positive for COVID. You can clearly see the control and test lines.

So, how does it work for COVID? When you have done your throat and nasal swab, you or whoever is carrying out the test will swirl the swab tip in a small amount of extraction buffer. This is a solution which will break down any virus particles, releasing their RNA; it also maintains the pH (acidity) at a constant level, because changes would affect the result. When you do your test, the control line will appear within a couple of minutes to show that the test is working. If the test is positive, the test line will appear within about 30 minutes.

Polymerase Chain Reaction

The enzyme used in PCR was isolated from bacteria that live around underwater thermal vents. This means that it can withstand the high temperatures used in PCR.

PCR is basically a process which uses an enzyme called polymerase to make multiple copies of DNA or RNA; this is called amplification. This means that PCR can detect extremely small amounts of either substance. One of the most widespread uses of PCR is in forensic science where it is used to amplify minute amounts of DNA to a level where it can be analysed.

In forensics, PCR is particularly useful in solving cold cases. Famously, PCR was used to identify the remains of Tsar Nicholas II and his family from very small samples of mitochondrial DNA.

PCR was used to identify the remains of the Romanovs.

The major advantage of PCR in testing for COVID is that it can detect the virus at much lower levels than LFT. This means that it is particularly useful in testing close contacts, who may have the virus but whose viral load is too small to cause symptoms or a positive LFT. Analysis of the swab is also carried out entirely by professionals working in sterile laboratories, so the potential for human error or contamination is very low.

A PCR machine

PCR has several disadvantages. It requires specialist equipment so must be done in a lab, making it more expensive. It also takes much longer. Amplification of the virus’ RNA using PCR requires multiple cycles of heating and cooling, taking several hours. Some people argue that because PCR is a multi-stage process, there is actually more potential for human error than with LFT; personally, I do not agree with this. PCR has been used for many years in forensic and diagnostic applications, and has consistently been found to be reliable.

So, should students who have had a positive LFT in school but a subsequent negative PCR be allowed back to school? Having considered all the scientific evidence, my opinion both as a scientist and as a teacher is yes they should. The argument is that LFTs in school are administered by staff, so they are more reliable than those done at home. That may be the case, but it certainly does not mean that they are more reliable than PCR, which is widely regarded as the ‘gold standard’ within the scientific and medical communities. To me, this is yet another example of the lack of medical and scientific understanding at the highest levels of government, but don’t get me started on that one!

Spanish Flu, and what it teaches us about social distancing

First of all, hi there to all my readers! I’m sorry I haven’t written anything in a while. Things have been intense with the day job – any teachers reading this will know that working from home and delivering remote learning is actually a lot more labour intensive than face-to-face teaching. Like so many other people, I’ve also been finding social distancing tough. I’ve been asked how I cope with it, and the simple answer is, because I know that I have to. In this article I will be looking at the 1918-19 Spanish Influenza pandemic, and explaining the lessons we can learn from it about social distancing.

It’s inevitable that parallels will be drawn between the situation now, and the Spanish Flu pandemic. This time 100 years ago, the world was reeling from a devastating global pandemic that had killed more people than the preceding four years of war.

It has been suggested that Chinese labourers brought the disease to Europe

The origins of Spanish flu have been hotly debated. There is speculation that the virus originated in China, and was brought to Europe by Chinese labourers working for the British and French armies – a theory that has been seized upon by conspiracy theorists looking for evidence of sinister Chinese involvement in the current pandemic.

Those studying Spanish flu, particularly epidemiologists, have a wealth of data to work with. It was the first global pandemic to occur in an age where there was good record keeping in both military and civillian hospitals.

The initial outbreak was probably Fort Riley in Kansas

Detailed studies of records kept by the US Army have actually narrowed down the origin of the disease to the state of Kansas, and the US Army training camp at Fort Riley. The evidence strongly supports the theory that the disease jumped directly from birds into humans, with ‘patient zero’ being a farm worker from a poultry farm who caught the disease just before enlisting in the US Army.

Wartime conditions were almost ideal for spreading the virus. After the first cases were reported, the illness spread rapidly through Fort Riley; movement of troops ensured that it spread rapidly to other camps and into the civilian population. Troops with the illness were sent overseas to fight, meaning that the disease very quickly spread to England and to continental Europe. It is ironic that the entry of the USA into the war, which was instrumental in bringing it to an end, also ensured that the Spanish flu outbreak became a pandemic.

Nurses in a military hospital treating a patient with Spanish Flu

I won’t dwell here on the disease itself and its effects. If you want to know more, I thoroughly recommend Lyn McDonald’s book ‘The Roses of No Man’s Land’ which contains harrowing first-hand accounts from doctors, nurses and others, of the effects of the illness in crowded military hospitals, camps and troopships.

Spanish flu spread rapidly on troopships such as the RMS Olympic (sister ship to the Titanic)

What I find interesting, and highly relevant, about the Spanish flu pandemic, are the lessons we can learn about social distancing. Wartime conditions meant that social distancing simply wasn’t possible – in fact, the opposite was the case with people crammed together in hospitals, training camps, troopships and, of course, the trenches themselves.

King Alfonso XIII of Spain became seriously ill but survived

Another, more pernicious factor that contributed to the spread of the disease was lack of public information. Basically, the public were not told about the illness for fear that it would damage morale in the critical final months of the First World War. People who could have practiced social distancing didn’t, for the simple reason that they did not realise there was any need to. The pandemic got its name because in neutral Spain, there were no restrictions on the press; they were even free to report when King Alfonso XIII became seriously ill. This led to a misconception that Spain was particularly hard hit.

Not only was social distancing not practised, the British government actually discouraged authorities from putting measures in place to limit the spread of the infection. Medical officers in large cities were discouraged from closing schools, churches, cinemas, theatres, dance-halls etc.; again, out of fears that this would damage morale.

Dr James Niven, medical officer for Manchester during the pandemic

One man who went against this was Dr James Niven, medical officer for Manchester. Against direct advice from the government, he closed schools and entertainment venues, and distributed posters and leaflets giving information about the illness and advice on how to protect against infection (mainly, ‘wash your hands’ – sound familiar?). Niven insisted on quarantine for those who were sick, gave regular interviews to the Manchester Guardian to keep the public informed, and took measures to deal with delays in funerals.

As a result, the rate of infection in Manchester was lower than in other large cities with similar population densities. The death rate among those infected was also lower, because medical services were now overwhelmed as they were elsewhere. High tech devices such as ventilators were not available in those days, but high quality medical care, particularly intensive nursing, could make all the difference between surviving or dying from the illness.

One of Niven’s posters informing the people of Manchester about the Spanish Flu

I’ve no doubt that during the Spanish flu pandemic, there were those living in Manchester who resented the restrictions. Why were their cinemas closed when those in other cities remained open? No doubt, too, there were those who regarded Niven’s information campaign as exaggerated or scare-mongering. I also am in no doubt that if I went back in time to 1918 and had to live in a large city in the UK, I would choose Manchester with its social distancing.

In my next post I will be discussing the differences between oxygen therapy, continuous positive air pressure (CPAP) and ventilation; and the role they all have to play in helping people survive COVID-19. Stay well and safe, everyone.

Social distancing: Why it’s important, and why we find it so difficult

Social distancing has been in the news a lot in the last few days here in the UK, mainly because we Brits seem to be very bad at it! Friends in countries that are locked-down, like France and Spain, are telling me how shocked and horrified they are by scenes this weekend of crowds flocking to parks, beaches and beauty spots. The UK government is threatening lock-down unless we start to take things seriously. In this post, I will discuss why social distancing is important, and some possible reasons why we are finding it so difficult.

Exponential growth curve for hypothetical ‘Virus X’.

Why do we need social isolation? Let’s think about how disease spreads. A person gets infected with a disease, we’ll call it Virus X. That first person to be infected is called Patient Zero. On the first day, Patient Zero infects two other people. On the second day, they each infect two more, and so on. After a week, we have 256 patients.

If each patient infects 5 people a day, then after one week there will be 78125 people with the disease. If each infected person passes the virus on to 10 people, then after a week there will be 1 million with the disease. You get the picture. This process is called exponential growth and is shown on the right. If the shape of that curve is familiar, it’s because you have probably seen it on graphs showing the number of cases of COVID-19 in the UK, like the one below.

Cases of COVID-19 in the UK. In blue, you can see a classic exponential growth curve.
Comparing the spread of ‘Virus X’ with and without social distancing.

How does social distancing help? Basically, unless an infected person is in close contact with someone else, they can’t spread the virus. Exponential growth will still occur, because there will always be some in the population who cannot practice social distancing, i.e. key workers. But the rate of exponential growth will be much slower. This is known as ‘flattening the curve’ and is shown on the left.

An additional consideration is that although discoveries about COVID-19 are being made at an unprecedented rate, there is still a lot that we don’t understand. When you get an infection, it will be several days before you start to show symptoms; this is called the incubation period and varies between different pathogens. When the level of the pathogen in your body drops below a certain level, your symptoms will go away; but you are not yet fully clear of the infection.

A few people have asked me why this pandemic is so different from the 2009 Swine Flu pandemic. With Swine Flu, we were dealing with a new strain of a very well understood virus. In particular, it is known that influenza viruses can only be passed on to other people by patients who are symptomatic. During the incubation and recovery periods, patients cannot pass the virus on except under exceptional circumstances. This meant that only those who were actually ill needed to be isolated. In addition, it is known that patients who recover from influenza viruses will then be immune to the disease.

With COVID-19, the incubation period is up to 14 days, and we still don’t know at what point patients become infections. We also don’t know how long it takes for recovered patients to cease to be infectious, and whether people who have recovered have immunity. We need to know whether immunity develops; how strong it is; and how long it lasts.

Look at the two diagrams below, showing the spread of the hypothetical Virus X through a population. On the left is the situation on Day 1, on the right is the situation after one week. The top diagram shows a population that is not practising social distancing, the bottom diagram shows a population that is. Speaks for itself, doesn’t it?

So, why is social distancing so difficult? Especially for us Brits, who historically have a reputation for doing as we are told. One reason is that we are having to break habits that have become ingrained over many years. Take this scenario: you are in a queue at the supermarket. The person in front of you moves forward, what do you do? You move forward too, to close the gap. This is not neccessarily deliberate, it’s a habit, and changing habits requires conscious thought. The good news is that it doesn’t take long for new habits to develop. I went shopping today (because I needed to, I hasten to add), and everyone was keeping their distance in the queue without needing to be reminded.

Another reason is people are used to freedom of movement. It’s a sunny spring weekend, the kids have been stuck in the car, let’s go to the beach because social distancing means no one else will be there. Unfortunately, hundreds of other people have had the same idea, and when you get there, it’s heaving. Do you have the strength of mind to turn the car round and tell the kids we aren’t going to the beach after all?

Recent panic buying is not helping either. Those of us who have continued to shop sensibly and responsibly have found that due to panic buying, we have had to visit multiple shops to get the basics. I’m trying to practise sensible social distancing due to my asthma, but it’s difficult when you have to visit 3 different shops to find toothpaste! Thankfully things seem to be settling down a bit. This morning I went to a local supermarket and was able to pretty much get my normal weekly shop, much to my relief!

Possibly the biggest barrier to social distancing, though, is the fact that we are primates, and by and large, primates are social animals. Our brains are not wired for isolation and I know I am not alone in worrying about how this will affect my mental health. However, there is a lot we can do to combat this.

The good news is that we live in an age where technology has made it easier than ever to keep in contact with friends and loved ones. So take advantage of Facebook, Zoom, WhatsApp, Skype and everything else that’s out there. Reconnect with people you’ve lost touch with. Share memories of good times! And keep remembering, social distancing isn’t forever; and the better we are at it, the less time it’s likely to last.

In the next couple of days I will be posting some ideas about simple experiments you can do at home to engage children with science while they aren’t at school, so watch this space! As always, if you have specific questions or concerns you’d like me to address, let me know. Stay safe and well, everyone.