On the 9th February a small group of members from Café Scientifique visited the National Grid Operational Headquarters in Warwick Technology Park. The trip was organised by one of the girls, and was extremely informative- we learned about the history of the use of fossil fuels, from the Industrial Revolution until now, and about where all the fuel we use comes from, as well as how high pressure gas is piped underground from the site to individual houses all over the UK. We also got to see the engineers who closely monitor the supply and demand of gas at work, and learned about how important their job is, not only for our comfort and convenience, but also our safety. I definitely enjoyed this trip as I realised how little I actually knew about where the fuel we cook with every day comes from, and what a complex job supplying it to the whole population of the country really is.
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On 22nd September, the members of Café Scientifique met to discuss Graphene.
Everyone has heard of carbon. It is an element on the periodic table. 6 protons, 6 electrons. Carbon based compounds are found in all living things. From the blue whale to the tardigrade and every living animal in between. There are many different allotropes of carbon. Diamond is one of the hardest substances known and is often used in cutting as the tip of drills. Graphite is soft and slippery and is used as a lubricant. Buckminster fullerene is in the shape of a football and is used in drug delivery systems. How can carbon atoms form structures that have such a wide range of uses? The answer lies in the bonding and structure of each allotrope. In diamond each carbon atom forms strong covalent bonds to four other carbon atoms in a tetrahedral arrangement. In graphite each carbon atom forms covalent bonds to three other atoms to give layers of hexagons. In Buckminster fullerene, each carbon atom bonds to four others to give a spherical structure. However, the most interesting of the allotropes of carbon is graphene. A two-dimensional substance that is one atom thick. Graphene is one layer of graphite. The chances are we have all made it at some point in our lives – just by writing with a graphite pencil. It was first isolated at the University of Manchester in 2004 by two professors. They removed some flakes from a lump of bulk graphite with sellotape. They soon noticed that some of the flakes of graphite were thinner than others. By separating the graphite fragments repetitively, they managed to create flakes which were just one atom thick therefore creating graphene! You may be wondering why this matters, how can a one atom thick substance have any use to us? It is important to remember some of graphene’s properties. It conducts electricity, it conducts heat, it is a 100x stronger than steel, it is the lightest material known to man. Still unsure? Graphene is one of the most in demand materials of today. In the beginning graphene was just integrated into a huge number and range of applications. It is expected to be used as efficient bioelectric sensory devices for example measuring glucose levels. Another idea is a graphene screen in your phone. At 97% transparent it is more than capable to be used as a material to replace the current glass screens. Perhaps a more surprising potential use of graphene is in ultrafiltration. This is due to a bizarre, but marvellous, property. Graphene allows water to pass through it but is almost completely impervious to other liquids and gases. Many people will have seen the adverts, whether it be Samsung or LG, for a graphene TV. Samsung have managed to produce a 30-inch sheet of pure graphene – one which is capable of being used as a TV screen. However, whilst these uses of graphene remain highly intriguing, the most exciting part of graphene is the fact that it is two dimensional. Imagine a 40cm by 20cm sheet of graphene. Length = 40cm Width = 20cm Height =? Now we know that graphene is one atom thick. So surely graphene’s height is the height of one carbon atom. But that gives graphene three dimensions – so that must make graphene 3D? No. You can only see graphene in two dimensions. Its length and its width. A human eye is not capable of seeing a height of one atom. Therefore, graphene is said to have three dimensions but be two dimensional and that is the real beauty of grapheme. Dr Davies is a global research fellow at Warwick Universities and kindly visited us to talk about her work in materials science. She focussed mostly on nanotechnology, which is usually of a scale 1000 times smaller than a human hair. Her talk began by demonstrating use (although not fully understood use) of nanotechnology in the 4th Century A.D, in the form of the Lygurcus cup. The glass in this cup appears a green-yellow colour in ambient light, but when a torch is placed in the cup the glass appears pink. This is due to imbedded gold nanoparticles in the glass, which means light interacts differently with the glass. Dr Davies then went on to talk about uses of nanotechnology in the present day, for example in suncream, cosmetics, carbon fibre technology and even self-cleaning windows, which use titanium dioxide to help degrade dirt when it rains. Even paints in hospitals contain silver based nanotechnology to kill bugs meaning walls don’t need to be washed down. She then went on to talk about the future of nanotechnology, including use as drones and as nanomachines for use in medicine.
Dr Davies then showed us some magnetic nanoparticles which have applications in biomedicine, as MRI contrast agents and for hyperthermic cancer treatment. She then developed upon their uses in MRI scans, explaining than adding nanomaterials enhances contrast as the speed of de-excitation (which releases the photons detected by the MRI scanner) varies. By binding silicon nanoparticles to the commercial enhancers, they can be used to identify diseases by effectively switching on and off. Finally she spoke about the use of nanoparticles for drug delivery, specially designed particles can be filled with drugs and get inside cells to deliver the drug without being detected by the cell. When disaster strikes, we run. We flee from drought and floods and hurricanes- and, if we’re lucky, we come back after the carnage has past. But what if you couldn’t? What if you were quite literally stuck where you put your roots down? Dr. Gifford, of the university of Warwick, is concerned with just that. She studies plants, and her new research topic delves into Plant Plasticity, or, to the layman, how plants adapt. On Thursday 13th October, Dr. Gifford came to talk to café scientifique about plant plasticity, and how plants with identical genes can have completely different phenotypes- so much so that to the average eye they can look like completely different species (called Phenotypic Plasticity). If you want to see an example of plants in extreme environments, you need only look at the ground the next time you’re on a motorway (café scientific does not accept any liability for any crashes caused). There are certain types of plants (usually weeds), which will grow between the cracks on the road. So, how do they do it? Basically, it comes down to their ability to adapt. There are two types of basic adaptation; they can become specialists, like the cactus, or they can be flexible (plant plasticity), which is where phenotypic plasticity (Same genes ‘turned on’ differently leading to different phenotypes) comes in. A popular question at this point maybe about drought- nothing can seem more baffling than looking at a picture of a barren waste land and seeing life. There are three things a plant can do to protect against drought: Avoid, tolerate and escape. A plants escape is to finish up its life cycle; to distribute seeds, and then die. If a plant were to choose the avoid mechanism, it might only grow at certain times of day, avoiding the worst of the drought (a bit like taking a siesta at noon to avoid the midday sun). The best way of describing tolerance is through the use of an example. The resurrection plant is a plant that basically shuts down until conditions and ok for growth. During this time it looks for all the world like a piece of tumbleweed. After good conditions, however, the plant ‘comes to life’. Like Dean from supernatural, it seems impossible to kill. (Great if you want a houseplant but also love holidays) Dr. Giffords research is concerned with what genes cause this, and can they be potentially transferred? Climate change is one of the biggest issues facing the scientific community to date. As global warming increases, we will be faced with increasing amounts of extreme weather. If they can use the Snorkel gene in, say the rice plant, which actually grows during flooding, and transplant it into agricultural crops, then they maybe able to prevent an entire years yield from being ruined by overflowing rivers or heavy rainfall. The next step in the Plant Survival Pack is to phone a friend. Plants can recruit bacteria to help them grow, which can enhance or increase the plants ability to absorb nutrients and grow, like nitrogen fixing bacteria. Plants in the Himalayas, which can seeming grow in impossible conditions, can attract a whole community of microbes and utilise resources that way. One of the first examples of microbes and plants working together is the theory of endosymbiosis, which explains why mitochondria have their own DNA, RNA and ribosomes, and also explains how plants first made the jump from sea to land. But, what relevance could this have to the world? Dr Gifford and her team are looking to create ‘smart plants’, which would be able to recruit bacteria- and the first is to look at how bacteria are taken up by the roots. They’re doing this through the use of florescent nanodots, which are easily taken up by roots. These dots are attached to microbes to find out what’s happening- at the moment they appear to be following the route of transpiration, so the next step for Dr.Gifford and her team is to add different sugar molecules to make the absorption more selective, and find the preferential route. If you want to find out more you can find Dr Gifford here: https://www2.warwick.ac.uk/fac/sci/lifesci/people/mgifford/ “If you go into outer space without protection, you'll die. The lack of pressure would force the air in your lungs to rush out. Gases dissolved in your body fluids would expand, pushing the skin apart and forcing it to inflate like a balloon. Your eardrums and capillaries would rupture, and your blood would start to bubble and boil. Even if you survived all that, ionising radiation would rip apart the DNA in your cells. Mercifully, you would be unconscious in 15 seconds.” Despite being slightly scared by this dramatic start to an article about the microscopic animals, Tardigrades, on the BBC Earth website, during their first meeting of the year Café Scientifique were fascinated that the weirdly adorable moss piglets/water bears/tardigrades could survive the hostile conditions mentioned above.
We discovered that these fascinating microscopic animals also known as tardigrades or water bears could survive temperatures between 1 and 373 Kelvin, live through pressures up to 6000ATM and enter an ametabolic state for over 100 years to simply come back to life when the conditions return to optimal. We were rather amused to here that one was revived after being in an ametabolic state for 120 years to simply twitch its leg, and die and slightly horrified that upon researching what would happen if you ate a tardigrade (as they seem completely undestroyabe) we found out that you and I alike eat approximately 2 every time we eat a piece of lettuce! |
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