Scientific Scribbles

The voice of UniMelb Science Communication students

Shrinking Down to Face Disease Head On

Disease as we know it is a thing of the past! The emergence of technology resembling a science fiction novel may be responsible for turning complex biomedical conundrums into tasks of simple engineering!

Ever since the days of Miss Frizzle and her magic school bus, the dream of shrinking ourselves down to fit within arteries, veins, cavities and tissues has excited the bioengineering community. Getting people with the right tools in close contact with blood clots, arterial plaques and diseased cells would make treatment of most diseases as easy as knocking down a wall.

Well the day has come! Shrink rays are shrinking test subjects all around the world and it won’t be long until we have the tools and the workforce to miniaturise our whole healthcare system.

Image by Patrick Redman via Flickr

Of course, I’m only joking. A real shrink ray goes against the very laws of the physical world, but the same concept of controlling a seek and destroy intervention against specific cells is being pioneered to increase the effectiveness of drugs and minimise their side effects.

While we won’t be sending ourselves down the plumbing of our insides, a breastroking magnetic field-following algae is happy to do it for us.

Chlamydomonas reinhardtii alga with two drug-containing microballs attached to its surface. Image by Yasa et al.

The alga, Chlamydomonas reinhardtii, is a single-celled microorganism with two flailing projections which allow it to swim through our body fluids at 100 micrometres per second. It has a negatively-charged body that lets us attach positive, drug-containing, microballs to its surface. And best of all, with the microballs being magnetic, you can use a magnetic field to steer them around in an (admittedly wobbly) straight line.

Video by Yasa et al.

With these three characteristics, this little green medic can be steered through the complex maze of our body to accurately deliver drugs against effected cells and tissues.

Most drugs used to treat our worst diseases have dire consequences for the our healthy cells if they are left to flood our body. The tug of war between a dose high enough to kill diseased cells but not high enough to kill or permanently injure the patient is always a concern.

But our new drug-carrying friend has the potential to abolish both these problems.

To deliver the drugs to the diseased area’s doorstep means the dose can be ramped up to an effective concentration without the risk of widespread side effects, and the alga has the characteristics to get it there!

So, while microscopic battlefields involving people and pathologies may remain a thing of fiction, enlisting tiny creatures to delivery our drugs within the body may be the thing that changes the way we look at disease treatment for ever!


What does an Earthquake’s Magnitude Mean?

Houses destroyed in Kathmandu after the 2015 earthquake. Photo by Nirmal Dulal via Wikimedia

Earthquakes are always going to be in the news. So far we haven’t found a reliable method to predict exactly where and when they will occur. But we do know enough about their frequency to say things like, for example, an earthquake of magnitude 7 or greater will happen about 20 times a year around the world.

But what does that magnitude 7 measurement actually mean? First off, these days that magnitude is short for Moment Magnitude. Lots of news reports will still use the term Richter scale but that hasn’t been used globally since the 1950’s and Moment Magnitude has been standard since the early 2000’s.

How much bigger is a bigger earthquake?

It’s reasonably intuitive that as the number gets bigger so too does the earthquake. But how much bigger? You might already know that the scale is logarithmic. This means that each jump of 1 in the moment magnitude scale represents an increase of 10. But what is not so well known is that the scale doesn’t really directly measure how strong the earthquake is. It measures the amplitude of the waves at the site. Due to the slightly complex nature of the equation used this means that in fact a jump of 10 times in the measured amplitude actually means a jump of 32 times in the energy released at the quake epicentre – that is the exact point where the earthquake occurs. So, an earthquake of magnitude 7 is actually 32 times stronger than one of magnitude 6 and 1,000 times stronger than a magnitude 5 earthquake.

Damage in Chile after the 1960 earthquake measuring 9.4-9.6 – the most powerful ever recorded. Image credit Buonasera via Wikimedia.

But, magnitude doesn’t really matter all that much

So, now we’ve got some understanding of what those magnitudes mean. A bigger number is a stronger earthquake. It’s pretty simple and that’s one reason why it is always reported in the news every time there is a big quake. But, now I need to tell you that that number just doesn’t matter all that much. For geologists it is important to know the size of the quake when studying it. But as people, it generally isn’t that important how big the earthquake is. Instead what matters is what it feels like and how much damage it does to the places we live.

How much damage the quake does is dependent on much more than how big the quake is. For one thing earthquakes happen in a three dimensional environment. They can occur close to the surface or even hundreds of kilometres below it. If a big quake happens a long way down you could be directly over it and it might still not cause much damage or feel very strong.

 

Shaking a brick vs shaking jelly

One of these substances makes a better foundation. Image credits Naib via Wikimedia and Andrew Lister via Wikimedia.

Another big factor is the type of ground you’re standing on. Imagine building two houses of blocks. One on a brick and the other on jelly. If you poked the brick it wouldn’t move much. But poke the jelly with the same force and it will wobble all about and the blocks will tumble. So it is on the earth. Bedrock, which often makes up hills, is like a brick, it’s solid and doesn’t wobble too much. Flat land like you find around rivers or bays is more like jelly. An earthquake will make it wobble violently and many buildings might collapse. Unfortunately for us most of our cities tend to be built on those flat pieces of land.

Liquefaction in Christchurch. At magnitude 6.3 the quake wasn’t particularly strong but the ground was like jelly and so holes like his opened up. Image credit perduta via Wikimedia.

This kind of information about how much a particular area shakes is the most relevant to how bad an earthquake is to experience. It is measured using the Modified Mercalli Intensity Scale which ranks the intensity in any area on a scale from 1 – 12 depending on the damage experienced. It is the most relevant gauge of an earthquakes severity for people. But, because the intensity is variable across an area for any earthquake, i.e. it doesn’t just give a single number, we very rarely hear about it during any news reports.

On top of all these geological considerations there are all kinds of cultural ones too like the quality of construction in an area which have a massive impact on how devastating an earthquake can be.

All this is to say that next time you see on the news that there has been a magnitude 7.4 earthquake, remember that that information is just the tip of the iceberg. It tells you only the most basic information about an earthquake, how strong it was. Everything that matters to people, how bad and how damaging the earthquake was, is better measured in other, more complex ways. That’s why we can see such different levels of destruction from earthquakes around the world even though the magnitudes might be the same.


High and dry: the impending water crisis

Turn on the tap and clean water rushes out. As much as we want. Any time we want.

The quest for this has been one of the defining struggles throughout human history. Today, 7 in 10 people can count on having running water in their homes. At least, so they think.

A global crisis

Droughts in Somalia. Water rationing in Rome. Fast depleting groundwater supplies in India. It doesn’t take an expert to realise we’re facing a global water crisis. And it’s getting worse.

The global water crisis is at a real inflection point where if we’re not careful, we may get ahead of our ability to manage it. Photo credit: Jacqueline Macou via Pixabay.

Climate change is warming the planet, meaning many regions around the globe are facing extended dry periods with more erratic water availability. The rain and snow we depend on to water crops and refill lakes and rivers is getting less reliable. By 2030, global demand for fresh water is predicted to exceed available supplies by 40 percent.

The flow on effects from this are enormous. Water shortages can reduce economic growth, spur migration, and spark conflict. A 2016 report by the World Bank estimates water scarcity could cost some regions as much as 6 percent of their gross domestic product in the coming years.

More people + more money = more demand

It’s a simple equation: as populations grow and incomes rise, so does water demand. This century water consumption has increased 7-fold. The world’s population currently expands at a rate of 83 million people per year. How will the planet satisfy our escalating thirst?

The problem is also exacerbated by rising incomes, because of the water-intensive products that richer populations demand. Things like meat and energy from fossil fuels have a larger impact on global water supply than many realise.

Nothing requires a greater amount of water to produce than meat. Growing 1 kilogram of alfalfa, a common ingredient in cattle feed, requires 510 litres of water. The average cow consumes 12 kilograms of feed a day, meaning a single hamburger takes around 1,650 litres of water to produce.

Water wastage

In most places in the world water is treated and priced like there will always be enough, so we end up using it in absurdly wasteful ways.

Arid Southern California is a primary producer of alfalfa. 2 trillion gallons of water are used every year to grow the crop, sourced from the Colorado River hundreds of kilometres away. The price farmers pay for the water doesn’t even cover its delivery, so the true cost of water doesn’t end up in the cost of the burger.

Alfalfa fields under irrigation in California. Photo credit: Ken Figlioli via Flickr.

India and China both grow some of their most water-intensive crops in their driest regions. In the United States leaky pipes account for the loss of 6 billion gallons of treated water each day.

Valuing the invaluable

Water is unlike any other commodity on Earth. Each of us will die in just a few days without it. And the scarcer it gets, the more access to it becomes a competition – with winners and losers.

In 2010 the United Nations recognised access to safe drinking water as a universal human right. This presents the real challenge of the water crisis – how are you supposed to value an invaluable resource while ensuring everybody has it?

All of humankind relies on just 1% of the Earth’s water to survive – liquid freshwater. Photo credit: account 84264 via Pixabay.

When the price of water is raised to fix pipes or encourage conservation it has the greatest impact on the poor. The solution may be that we don’t end up treating all water equally. To satisfy basic human rights, each individual requires 60 litres of water per day. The cost of water could be increased for usage beyond this amount. In 2015 Philadelphia started experimenting with tying water prices to income, which saw drastic reductions in its consumption.

It’s not too late

Valuing water as we should means we wouldn’t be growing water-intensive crops in really arid places, because the economics of it wouldn’t make sense. Efficient water use in the home and industries would be incentivised.

Amidst the doom and gloom, it’s not all bad news. Around the globe people are waking up to our water challenges and starting to act. Each year brings more solutions – like improvements in desalination, greater investment in infrastructure to ensure water security, and using wastewater for energy.

The challenge is realising how valuable water is before there isn’t enough of it. And remembering that our fates are tied to what runs out of our taps.

 

Further reading:

https://news.nationalgeographic.com/2018/03/world-water-day-water-crisis-explained/

http://www.worldbank.org/en/topic/water/publication/high-and-dry-climate-change-water-and-the-economy


A cat-astrophe waiting to happen!!!

Friend or foe?

When you look at your fluffy pet cat curled up beside you on the sofa, do you see a cute companion or a calculating killer?

Cute companion or calculating killer? Credit: Author’s own.

I’m going to assume the former, but now let me ask you this: Do you let your cat outside, even for five minutes a day? If so, unfortunately your feline friend could be the purr-fect example of an apex predator, at the top of the food chain, willing to kill any small creature, whether feathered, scaly, or furry, that may get in its way.

A game of cat and mouse.

Cats are generalist predators, meaning they have a varied diet, and feed on small mammals, birds, reptiles and invertebrates. Furthermore, they do not eat everything they kill: often hunting for sport. A study back in 2013 found that only 28% of cat prey items were consumed.

Yes, this may be hugely beneficial if you have a mouse problem in your house…I know my tabby cat saved our larder of food from countless hungry rodents during her 24 long years of life! However, for a country that has such a high rate of endemism, it is extremely problematic for Australia’s wildlife. In addition to this, 30% of Australia’s endangered wildlife can be found in towns and cities, where the majority of domestic cats roam.

Cats are a threat to Australia’s wildlife. Credit: Author’s own.

Due to being raised in the UK the concept of keeping an indoor cat was a little alien to me. What if it gets bored? Will it be staring out of the window at all hours, desperate to be out?

The short answer is no, not if you, the cat owner provides them with entertainment.

Unlike in the UK, Australia’s wildlife has evolved for centuries without this introduced, unnatural predator. This is the same case in New Zealand, where numerous native bird populations have been almost obliterated due to predation by cats and other non-native predators.

New Zealand endemic birds are at risk from introduced predators. Credit: Author’s own.

A trail of destruction…

When left to roam outside domestic cats can leave behind a trail of destruction. Pet cats kill over 61,000,000 birds and 53,000,000 reptiles a year in Australia . No, my ‘0’ key did not get jammed… the numbers really are that staggeringly high!

Not only can it be devastating for the wildlife in your backyard if you allow your cat to roam outside, but it can also be a huge risk for your pet. In Australia almost ¾ of cat owners have lost a cat due to car accidents, fighting with other animals, or getting lost and not returning.

Safe Cat, Safe Wildlife

So, what can you do? Zoos Victoria teamed up with RSPCA Victoria to launch a campaign entitled ‘Safe Cat, Safe Wildlife’ that encourages and supports cat owners to keep their cats indoors. They have created an online ‘cat community’, which can be accessed by visiting http://www.safecat.org.au. This platform provides useful advice, exclusive discounts and cat hacks to keep your cat entertained indoors. Hacks that include using bubble wrap as cat bedding and providing your feline friend with a sprig or two of mint as a tasty treat!

An entertained cat is a happy cat. Credit: Author’s own.

So, if you’re a cat owner consider the benefits of keeping your beloved friend safe within the home. Or if you know someone who owns a cat, please pass on the message:

A safe cat = safe wildlife.

It’s a win-win scenario and a good excuse to cuddle your cat, kick back with your kitten, or frolic with your feline! Indoors, of course…


Time to think big!

Just how big, is big? An elephant? A blue whale? A skyscraper? The moon? The burden of guilt you’ve carried since grade 3 when you lied to your teacher about stealing a packet of Sakatas but your classmate Steven took the fall and ended up with a 15 minute detention? Well, I can definitely tell you, we can go a lot bigger (maybe not bigger than that last one though… Steven if you’re reading this, I never meant for you to get caught up in it all, Ms Clancy was a damn scary teacher). So buckle up and get ready to take a tour through the massive objects we can find in our universe.

Star-ting small (but really, quite big)
To start our journey into the world of big, lets first take a look at our very own star, the Sun. Weighing in at 330,000 times the weight of the Earth (1.989 x 10^30 kg), this bad boy accounts for 99.8% of the mass of the entire solar system! Diameter wise, though, only 109 of Earth could fit along the face of the Sun (1.4 million km), and volume wise it only takes up a smidgen of all the space in the solar system. We could go on about the Sun all day, but I’m sure there are some of you reading who might get fed up pretty quickly… so time to move on to other stars!

If you thought the Sun was big, get ready for a big surprise. As far as stars go, the one we orbit really ain’t that much to talk about. To kick things up a gear, we can start with Aldebaran. This red-orange giant star, located around 65 light years away from us, is 150 times brighter than our Sun, and is as wide as 52 Suns lined up! That’s 5668 Earths! We are only on the second item in our ‘list of big’ and we’ve reached sizes that are pretty hard to comprehend.

Next up is the first of the super-giants, Rigel. It is about 85,000 times brighter than the Sun, and has a width 70 times larger than the sun. But stars can get so much bigger! So let’s quit beating around the bush and move on to the biggest: VY Canis Majoris. This baby has a diameter of 2.7 billion km. This means that lined up side to side, you could fit 2000 of our sun in that space. Volume wise, you could fit 9.3 billion of our Sun in there. What’s more, is Canis Majoris is expected to explode in around 100,000 years in a supernova! Fortunately, this star is around 4,900 light years away from Earth, so if anyone is around when this guy blows, all they might see is an extra bight twinkle in the night sky.

Scaling up to galactic proportions
The next big step up is onto galaxies, massive systems comprised of millions or billions of stars, dust, and gas, held together by the force of gravity. The Milky Way, our own galaxy, is believed to contain upwards of 150 billion stars. How big is it then? 100,000 light years! Sizes like this are when you really have to stretch your imagination to think about how big they really are. If you were to drive at 110 km/h, it would take 1 trillion years to cross the diameter of the Milky Way. Unfortunately there won’t be many service stations in space, so refuelling and pee breaks might be stretched thin!

However, galaxies themselves can cluster into groups, also held together by gravity. Moving onto these galactic clusters, we are finally approaching the biggest structures in the universe. The Milky Way itself is a part of the small ‘Local Group’ that is comprised of around a couple dozen galaxies. Included in this cluster is our closest neighbouring galaxy, the Andromeda galaxy (Fun fact: in around 4 billion years, the Milky Way and Andromeda will actually collide!).

Finally, to top it all off, galactic clusters can also cluster! These incomprehensible structures are not so imaginatively called superclusters. The biggest of them all, the biggest known structure in the observable universe, is called the Great GRB Wall, and is 10 billion light years across. As a matter of fact, this has confounded astronomers, as theory suggests structures this size shouldn’t be able to exist!

We’ve now reached the end of the list, and ticked off the biggest structure within our universe. So hopefully this can provide you with some insight to the guilt I have felt towards the Steven Sakata Saga.

Tune in next week, when we discuss the smallest things in the universe, such as atoms, electrons, the Planck distance, or the amount of will I have left stopping me from dropping out of uni and taking up a career as a demotivational speaker.

PS. If visual comparisons are more your thing here’s a great (albeit, a bit long) video showcasing the true scale of the things I mentioned in this post:


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