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Monday, 16 May 2016

Solanezumab and Alzheimer’s

If you had been sitting in the main room of the 2015 Alzheimer's association international conference, you would have heard a remarkable announcement: a drug - Solanezumab - has been found to delay the course of Alzheimer's disease. Now that is a rare thing - 99.6% of all drugs designed to combat Alzheimer's have failed in trials since 2002. Just four have been approved for use. None of those four target the underlying cause of the disease (they just ameliorate the symptoms). But Solanezumab claims to be different.

Image illustrating the effects of Tau molecules on neurons courtesy NIA
The “plaques” and “tangles” found in the brains of Alzheimer’s patients are caused by two proteins behaving abnormally; beta-amyloid is thought to usually be involved in neuronal development, but in many Alzheimer’s patients the protein is not processed properly. The incorrect processing leads to a build-up of large amounts of beta-amyloid as the protein loses its solubility. The higher concentrations lead to this protein creating large aggregates known as “plaques”. “Tangles” are instead caused by the protein “tau”, which in Alzheimer’s patients has too many phosphate groups added to the protein, this makes tau clump together within the nerve cells.[3] Image credit: National Institute on Aging (public domain)

Thursday, 17 March 2016

What causes hangovers?

What causes the dreaded hangover? The answer is simple, right? It’s alcohol. But how does alcohol cause hangovers? The answer is less straightforward.

Photograph of badge with writing Hangover On Board and the London Underground logo
Evidence of alcohol dates as far back as 10,000BC. We suspect hangovers do, too.
Image credit: Annie Mole, via Flickr (CC BY 2.0)

Some will say it’s dehydration, others will blame your electrolyte balance, or blood sugar levels, whilst insisting you ingest copious volumes of orange juice. But whilst orange juice might ease hangover symptoms, it doesn’t cure it. In fact, we don’t know of any reliable hangover cure at all - probably because even though the hangover predates the Egyptian pyramids[1], how it comes about remains a mystery.

A major reason for this massive void in our understanding is the fact that almost nobody seems to be researching it. It’s like we don’t care. Whilst the glut of folk remedies tells a different tale (we do care - we don’t want hangovers), some argue that hangovers are better left not understood so that we can’t cure them. Hangovers are an incentive to drink less, a natural mechanism that, if removed, could lead to widespread drunken barbarity with no comeuppance for the perpetrators. On the other hand, it’s important to point out that not all hangovers are equal. Some people don’t even get hangovers (23% - either because they never drink to excess or they’re just very lucky). We don’t know why this is either, but it does challenge the idea that removing hangovers would lead to epidemic alcoholism, or that experiencing a hangover is somehow “fair”.

And this isn’t all we don’t know about alcohol. We don’t know how alcohol causes mood swings, lowers inhibitions and reaction times, or makes us clumsy and bad at driving. We don’t know whether curing a hangover could lessen the damage caused by alcohol - combining making it easier to drink with making it safer - it’s certainly possible, but we can’t know until we know more about hangovers.

Saturday, 6 February 2016

100,000 Years Later

The problem of making future predictions about the destiny of long-lived nuclear waste.

What is nuclear waste?

Depending upon what you put into a nuclear power station and how you operate it, you get different products out. Most reactors use uranium dioxide fuel, UO2, and over 90% of the “spent fuel” is still uranium compounds, with a little plutonium. Although it is called spent fuel, so much uranium still exists that it may be recycled to generate more electricity and remains hot for years. However, “ash” products that absorb neutrons and slow the reactions build up as the fuel operates, the rate that energy is produced drops and stops being efficient. Then the fuel will be replaced, useful uranium extracted and recycled and the rest disposed of.

Some kinds of reactors extract more energy and are more efficient, such as fast breeder reactors. These make products like plutonium-239 (Pu-239) that sustain the chain reaction - nuclei falling apart and giving off energy. When the rate plutonium-239 is produced is faster than it is used up, the reactor can get 60 times as much energy from the original uranium and more plutonium products result. However, there are no fast breeder reactors in the UK because plutonium-239 is one component used to make nuclear weapons - not something you want to be storing in large quantities. Plutonium-239 and other minor actinide products of nuclear power generation remain dangerous for over hundreds of thousands of years. Although the longer a radioactive material remains dangerous, the lower the danger (because they produce radioactivity more slowly), fresh spent fuel is so concentrated that standing unprotected before it would get you a lethal dose in seconds, and you would die of radiation sickness in days.

How can we store nuclear waste?

Saturday, 31 October 2015

Our face spiders - friends or foes?

You may be surprised (or perhaps horrified) to know that you have spiders on your face right now. In addition to the millions of bacteria, viruses and fungi that make up our skin microbiome (the community of microorganisms on our skin) we have microscopic eight-legged creatures that also make a home in our skin. In humans there are two species; Demodex folliculorum which reside in our hair follicles and Demodex brevis which are found in our sebaceous glands[1]. They are just two of the 46,000 different species of mites that form the Arachnid family along with spiders and ticks.

Thankfully, the arachnids on your face aren't as big as this Christmas Lights Jumping Spider! Jumping spiders sometimes follow convoluted routes when hunting, even losing sight of their prey. How and why they do this, especially given the size of their brains, is also an open question. Image credit: public domain, via USGS (Flickr)

While studies suggest that we aren’t born with these creatures on our skin, but acquire them over time as a result of skin to skin contact with our mothers, how the spiders get onto us remains a fundamental mystery. Their numbers increase as we get older, but we don’t know why this is[2,3]. To date scientists have been unable to culture Demodex long term outside the body, as they dry out very easily[4,5]. As a result they are difficult to research and little is known about their life cycle apart from the observations of Spickett in 1961. He suggested that the mites roam the surface of our skin at night in order to breed. Females lay eggs within our hair follicles where they hatch and develop into adults and the cycle starts again[6].

Thursday, 22 October 2015

The Energy of Atoms (other than Hydrogen)

Whilst the things we don’t know about quantum mechanics could fill a black hole, it’s still thought of as a glorious theory that swept in and revolutionised atomic theory. In a way it has, well, revolutionised one atom: hydrogen. Because that’s the only atom we know how to “solve”.

Hydrogen atom cartoon copyright TWDK / R. Fletcher-Wood
The hydrogen atom consists of just one proton in the nucleus and one surrounding electron: a simple system to model. Image credit: TWDK / Rowena Fletcher-Wood

Monday, 21 September 2015

Location, Location, Location

Nuclear power and nuclear waste are sensitive public issues. Whilst the Finns are already building a geological disposal facility in Onkalo, in the UK we still haven’t decided what to do with our waste. Before the site can be chosen and built, a formal, scientific safety case must be completed, evidencing the likelihood that the containment facility will remain intact on a timescale of at least thousands of years. Learning from the “Yucca Mountain controversy”, where the state of Nevada legally opposed the construction of an American disposal facility on the grounds that they didn’t want to be lumbered with the country’s nuclear waste without consent, the UK government are waiting for volunteer communities to emerge before they can even start studying local geology in detail. Huge climate and geological changes, including at least one ice age, are predicted, which would totally change the landscape, the exact impacts of which could vary widely depending on where nuclear waste goes.

Low-level waste storage pit at the Nevada National Security Site
Nuclear waste is divided into three categories: High, Intermediate and Low Level Waste. High Level Waste is what's left after spent fuel is recycled to extract as many reusable uranium and plutonium fuel isotopes as possible. This waste is usually vitrified: transformed into a glass by fusing with borosilicates at high temperature. Intermediate and Low Level Wastes are non-fuel items (such as containers) that have been or may be been contaminated during normal operation of the nuclear power plant, and comprise the bulk of the waste. Image credit: Nevada Test Site Guide (public domain)

Tuesday, 8 September 2015

Do cheaters prosper?

Attempting to selfishly gain an immediate advantage in a situation where others are co-operating is called social cheating. Many people are likely to bitterly recall an experience of this, queue jumping is a classic example, and a wide variety of other organisms undergo the same injustices. Cheaters in theory should have an evolutionary edge, but social co-operation remains at the base of almost all populations. This is a mystery that scientists have been intrigued by for years, as there is very little we really understand about these behaviours and how they co-exist.

Social systems can be ‘modelled’ in much simpler organisms than us; the social amoeba for example. Dictyostelium discoideum (Dicty), are generally alone throughout their lives, but for one 10 hour period. This time is where they become social in order to release spores that will grow into new amoebae. To do this they form ‘fruiting bodies’, where some Dicty give up their lives and harshly but more importantly; their bodies. These form a stalk, the top of which the spores can be released from. However some Dicty cheat - there are amoebae that climb straight to the top to release their spores and contribute less to the stalk. By doing this they release more spores than other, co-operating amoebae and so gain an evolutionary edge, passing on more of their genes. But this advantage cannot be significant, as otherwise they would overrun the co-operators and drive them to extinction.

Photograph of stalked slime mould fruiting bodies, by Lairich Rig (CC BY-SA 2.0)
The Dicty amoebae begin as single celled organisms, before congregating as a multicellular ‘slug’, which then gives rise to fruiting bodies with spores atop long stalks. In the species shown here, each of the sporangia was 2-3mm tall. Image credit: © Lairich Rig, via geograph (CC BY-SA 2.0)

Wednesday, 2 September 2015

The Inspirational Butterfly

An Insight into Developments in Solar Power

The UN is calling for drastic action to be taken to stop climate change in its tracks. With any luck an agreement will be reached this year on the actions that will need to be enforced by 2020 to tackle this worldwide issue[1]. As a result, countries are desperately attempting to reduce their carbon emissions, and focus on renewable energy sources is increasing. If the right developments are made to improve efficiency and distribution of renewable sources, we could be one step closer to establishing a sustainable worldwide energy supply and battling the ongoing threat of climate change.

The prospect of being able to harness energy from the Sun is one that has captured our interest given its relative reliability, and solar power is already a widespread phenomenon. However it does not yet compare to the cost of generating power from fossil fuels, and a result is often considered to be less economically viable.

Electrical apprentice Eric Penel works on the solar reference array, which has been installed on the roof of the Shaw Theatre at NAIT's Main Campus in Edmonton.
The UN conceded in the Kyoto Protocol that limiting global warming to just 2 degrees, relative to the pre-industrial temperature level, would be necessary to reduce harmful climate impacts. For this to be achievable a 75% decline in carbon emissions by 2050 would be necessary[2]. If innovations in solar power continue to progress at the current rate, it could become the world's largest energy source by 2050. Today, solar photovoltaics and concentrated solar power contribute 16% and 11% to global overall consumption, respectively[3]. Image credit: Northern Alberta Institute of Technology via Flickr (CC BY-ND 2.0)

Given the positive effect a switch to solar power could have on the climate, there is much ongoing research into whether the efficiency of solar power can be improved. Inspiration for this goal can sometimes be found in the most unlikely of places..