1
2
CONTENTS Perovskite Solar Cells
4
Myla Jeyagugan
4
Integra- Artificial Skin
6
Kate Walters
6
How Twistronics Can Be Used for Resilient and Robust Superconductors Abigail Goodrick-Green
8 8
Will Cosmic Rays Stop Us From Going to Mars?
10
Honey Morrison
10
Robomorphic Computing
13
Charlotte Fox
13
Magnetic Graphene
14
Amélie Gadsby
14
Physarum Polycephalum- the Slime Mould that Stores Memories Greta Large
16 16
Parkinson’s Reversing Neuron Grafts
18
Fope Akinyede
18
The Placebo Effect: The Science and Ethics Behind the Mystery Maaira Khan
20 20
3
Perovskite Solar Cells What is a perovskite solar cell (PSC)?
Myla Jeyagugan
A perovskite is a type of solar cell that is made using a perovskite material. Perovskite materials are compounds that have the same crystallographic structure as the mineral perovskite, CaTiO3. The structure can be described as a cation at the centre of a cube with the cation surrounded by 6 anions in a bi-pyramidal structure and the corners of the cube are occupied by another cation.[1] Some perovskite materials have many useful properties such as:
• •
•
Superconductivity[1] – when a material can conduct electricity with no resistance. Ferroelectricity[1] – this is when the direction of spontaneous electric polarisation can be reversed when an electric field is applied to it.[2] Colossal Magnetoresistance[1] – an extreme change in electrical resistance caused by the introduction of a magnetic field.
The structure of perovskite: the green and red ions are cations, the blue ions are anions
How do perovskite solar cells work? Perovskite solar cells use photovoltaic technology to produce electricity. They absorb UV light and convert it into electricity. The perovskite layer absorbs the light. The conversion from light photons to electrons is extremely efficient, making it a popular renewable energy source. [3]
How is a perovskite solar cell created?
Methylammonium lead triiodide (CH3NH3PbI3) is a common compound used in perovskite solar cells. Firstly, a layer of lead iodide (PbI) is added. Then you add the methylammonium iodide (CH6IN) which will then react with the lead iodide to form the perovskite layer.[4] To complete the solar cell a hole transport layer, electron transport layer and a transparent conducting oxide layer is added. There are varied structures of the solar cells such as the inverted structure (where the hole transport layer and the electron transport layer switch) and the mesoporous structure.[5] An example of the different layers in a perovskite solar cell
4
What are the advantages of using perovskite solar cells? Perovskite solar cells have shown great potential in light-to-electricity conversion efficiency. Perovskite photovoltaics improved from ‘2% in 2006 to over 20.1% in 2015’.[1] The low cost to produce the perovskite material also makes it desirable in a commercial setting. What are the disadvantages of using perovskite solar cells?
Perovskite materials are not durable due to their tendency to degrade when faced with ‘external factors such as water, light and oxygen’. [5] They lack stability which prevents them from being used as a long-term solution to the increased use of renewable energy.
The lead used to create the perovskite layer of the cell is a cause for concern due to its toxic properties. It is argued that the small amount of lead used will not provide too big of a risk to the environment, however the real risks may occur when perovskite solar cells are produced on a larger scale and the lead from many cells leaches into the surroundings. Tin based perovskites have been introduced as an alternative.[5] Where can we see perovskite solar cells in the future?
Developing the solar cells to improve their stability in different conditions and reducing the toxicity are both major obstacles that need to be overcome before they can be considered for commercial use. Perovskite materials will have many uses in the future of material science due to their low production cost and useful features, however, until they can be proven to be both safe and reliable in the long-term, it may be a while until we see them being used in our daily lives. Sources:
[1] What is a Perovskite material? | Perovskite-Info (perovskite-info.com) (accessed 28/02/21) [2] Britannica, T. Editors of Encyclopaedia. "Ferroelectricity." Encyclopedia Britannica, March 28, 2018. Ferroelectricity | physics | Britannica (accessed 28/02/21) [3] Perovskite Solar Cell - Clean Energy Institute (washington.edu) (accessed 28/02/21) [4] Making perovskite solar cells - YouTube (accessed 28/02/21) [5] Perovskites Solar Cell Structure, Efficiency & More | Ossila (accessed 02/03/21)
5
Integra- Artificial Skin Kate Walters
What is artificial skin and what has it been used for?
Artificial skin has been under development since 3000BC. It was first used to repair skin damage on the ear using skin from the buttocks, and in 2002 it was approved by the FDA for treatment of diabetic foot ulcers through dermagrafts (replacing damaged dermis). [1] Nowadays, Artificial skin has the primary function of treating skin damage by burns, with the aim of providing protection from infection, dehydration and protein loss via the skin after severe damage. Also, a long-term wound coverage is preferable to optimise the function of the patient’s limb or damaged area, after surgery. [2]
Integra is one of the many synthetic skin substitutes, and it is used to help patients who do not have enough donor skin to cover damaged areas. Integra is a matrix of glycosaminoglycan and collagen, presented in the form of a two-layer sheet placed on the wound bed to act as a temporary skin replacement. It mimics a scaffold, stopping any pathogens entering the body through these areas, but also triggers blood vessels and new cells to migrate into the matrix and form a new dermis in the areas that had been damaged. [3] What is collagen?
Collagen is a strong, insoluble fibrous protein and the most abundant in mammals, therefore having the benefit of being readily available for treatments like Integra. It is a primary component in connective tissue, the bones and muscles. When used in treatments such as integra, the collagen is often sourced from the connective tissues of animals, for example chicken or pork skin. [5] How do collagen’s chemical properties make it suitable for its role? Collagen proteins consist of 3 polypeptide alpha chains coiled together to form a triple helix. When single collagen proteins are packed together they form multiple linkages, giving collagen it’s tough physical properties. The three abundant amino acids in collagen: glycine, proline and hydroxyproline form peptide bonds with one another, keeping the molecule tightly packed together in a fibre mesh. [4] Moreover, hydrogen bonding between oxygen and hydrogen atoms create strong intermolecular forces of attraction, and this along with collagen’s other chemical properties contribute to its strength. [5] Collagen is also chemically inert meaning it will not react with any foreign substances it comes into contact with. This provides a reliable scaffold for dermal cells to grow off of, and the glycosaminoglycan within the matrix can stimulate the cell to produce its own collagen, which will over time replace the artificial layer. Glycosaminoglycans (GAGs) are polysaccharides with repeated acidic and basic disaccharide units which are also found in human connective tissues. These play a crucial role in cell signalling and wound repair. [6] 6
Treatment The integra sheet once over the damaged area, needs time to attach itself to the body in order for a person’s own tissue to replace it, by growing into it. This process takes approximately three weeks, and dressings are needed until that point, in order to keep the wound sterile. Below is the healing progression of a severe burn wound treated with Integra, with a better visual appearance one month after treatment and only faint scars six years on. This is a strong indication of Integra’s success, as for many 2nd or 3rd degree burns leave noticeable scars for life. [2]
Sources: [1] https://www.woundsinternational.com/resources/details/dermagraft-in-the-treatment-of-diabetic-footulcers [2]https://openwetware.org/wiki/Artificial_Skin,_by_Katie_Geldart#:~:text=The%20primary%20current%20 application%20of,or%20damage%20on%20burn%20patients.&text=The%20most%20important%20goals% 20of,severe%20skin%20loss%20or%20damage [3]https://www.verywellhealth.com/integra-skin-graft-4796663 [4] https://www.ncbi.nlm.nih.gov/books/NBK21582/ [5] https://www.slideshare.net/DrGauriKapila/collagen-55683533 [6] https://www.sciencedirect.com/topics/medicine-and-dentistry/glycosaminoglycan https://openwetware.org/wiki/Artificial_Skin,_by_Katie_Geldart#:~:text=The%20primary%20current%20ap plication%20of,or%20damage%20on%20burn%20patients.&text=The%20most%20important%20goals%20 of,severe%20skin%20loss%20or%20damage
7
How Twistronics Can Be Used for Resilient and Robust Superconductors Abigail Goodrick-Green
Whilst our understanding of superconductors is limited, the nature and variety of superconductors is of particular interest in the fields of material science, engineering, and physics. This is largely due to their ability to repel a magnetic field, which is beneficial for applications of high-field magnets for nuclear magnetic resonance, (NMR) spectrometers, and magnetic resonance imaging (MRI) machines [1]. This phenomenon, known as the Meissner Effect, is due to the lack of resistance that the free electrons experience at certain temperatures, allowing them to expel magnetic field lines. The potential for superconductors to allow a flow of current with zero resistivity is crucial in the development of a variety of technologies such as low-loss power cables, fast digital circuits, and fast fault current limiters. [2]
Diagram showing a cooled liquid nitrogen superconductor, which expels a magnetic field causing the levitation of a magnet
Although many superconducting materials have been researched since their discovery in 1911 such as metallic mercury and Yttrium barium copper oxide [3], there has been no definite theory regarding the cause of superconductivity, making it challenging to optimise them. Moreover, many traditional superconductors require extremely low temperatures and high pressures. The temperature at which the material exhibits superconductivity and experiences zero resistivity is known as the superconducting transition temperature (Tc) and for many materials this can be as low as 0.88 K (Zinc) [1]. Consequently, both the tunability of superconductors and capacity to have a high transition temperature have particular importance in scientific research. Fortunately, tuneable strongly coupled superconductivity has emerged through the use of magic angled twisted layered graphene. This layered graphene is known as a moiré system and are beneficial for use in superconductors due to the enhancement of local electrodynamic interactions (electron-electron dynamics) through the decrease in coulomb repulsion. Additionally, moiré systems generally have an increased density of states (DOS) at the fermi level, so act as better superconductors [4]. Having a high density of states is a key property for superconductors and arises from poor electron orbital overlap. This poor orbital 8
overlap causes a strong electron-lattice interaction which results in a distortion in the lattice as an electron moves through. Importantly, this increases the transition temperature (Tc). [5]
Twisted layered graphene was discovered in 2018 in the form of bi-layered graphene, where researchers rotated the sheets by 1.1⁰, demonstrating a remarkable ability to create a large-scale moiré pattern. Once the electrons in the graphene encounter an electric field, the material properties can be altered for use as a conductor and as an insulator. Whilst this “magic angle” of 1.1⁰ can be hard to replicate on a large scale due to the precision required and the tendency of the sheets to wrinkle, the versatility and advantages of this feature cannot be understated. Propelling our understanding of superconductors, gaining control over a material, and having applications in quantum computers and astronomy, further research in this emerging field of twistronics was required. [6]
Recently, a more tuneable, versatile, and robust superconducting material of twisted tri-layer graphene has been discovered thanks to a team of people primarily by Jarillo-Herrero and a group of Harvard researchers led by Philip Kim. In tri-layer graphene when the central layer is twisted at 1.55⁰ relative to the top and bottom layers, the electron pairing is strengthened, allowing for high Tc superconductivity. These tri-layers allows for more flexibility than the bi-layered graphene and when imperfections in the twists of the layers were observed to be 1.69⁰ and 1.35⁰, the structure behaved regularly (as if it has a twist angle of 1.55⁰), proving that the structure could readjust itself [7]. Furthermore, the tunability of the material increased, allowing researchers to explore its superconductivity more and the strengthened interactions between the coupled electrons, allowed for a more robust and resilient material [8]. These resilient materials that operate at a high Tc, are paving the way for future exploration of superconductors.
Sources: [1] https://chem.libretexts.org/Courses/Howard_University/General_Chemistry%3A_An_Atoms_First_Approa ch/Unit_5%3A_States_of_Matter/Chapter_12%3A_Solids/Chapter_12.07%3A_Superconductors
[2] https://eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Ma gnetic_Properties/Meissner_Effect [3] https://pubs.acs.org/doi/abs/10.1021/ja00242a056
[4] https://doi.org/10.1016/j.aop.2020.168118 [5] https://arxiv.org/ftp/arxiv/papers/0904/0904.2038.pdf [6] https://arxiv.org/abs/1808.07865 [7] https://arxiv.org/abs/2012.02773
[8] https://www.sciencedaily.com/releases/2021/02/210204143221.htm 9
Will Cosmic Rays Stop Us From Going to Mars? What are cosmic rays?
Honey Morrison
Cosmic rays are not actually ‘rays’ as the name suggests. Having been named, it was later understood that they are actually highly charged particles which move through space at almost the speed of light. They were first discovered by Victor Hess in 1912, when he measured atmospheric radiation at various altitudes by travelling in a hot air balloon. The radiation levels initially decreased as he started to gain height, but then increased rapidly. At a height of several miles, the radiation was even greater than that on Earth. Data from the Cosmic Ray Isotope Spectrometer (launched in 1997) measured that 89% of particles which make up cosmic rays are hydrogen nuclei. This was then confirmed by the AMS (launched in 2011) onboard the ISS. In addition, 10% are nuclei of helium and 1% are other heavier nuclei (all the way up to uranium). It is unclear where these highly charged particles have come from, most theories suggest that they were accelerated in the blast waves of supernova remnants (at the end of a star’s life it explodes, called a supernova). However, cosmic rays have been discovered with greater energy than supernova remnants can generate, so it remains a big question in astronomy. Why are they a problem?
These highly charged particles are extremely ionising, which means that astronauts are exposed to high levels of radiation that could lead to cognitive disfunctions, cancers and other cardiovascular diseases. On Earth we only experience an average of 1 millisievert per year, whilst in space you would receive an average of 700 millisieverts per year. To overcome this, astronauts on the ISS only stay for limited periods of time - normally 6 months. How are we protected from cosmic radiation on Earth?
We are protected on Earth by both the atmosphere and magnetic field. As these highly charged particles hit the atmosphere, they interact with other particles in the atmosphere to create subatomic particles (muons, neutrons, electrons and photons) which are less ionising.
Cosmic rays are deflected from the magnetic field of Earth just like an electron in a current. Sometimes, these react with the upper atmosphere and cause the neon lights we see as the northern lights. The yellow green colours are made from interactions with oxygen, and interactions with nitrogen cause blue or purple colours.
Illustration of a cosmic radiation
How could we create a magnetic field on Mars?
The first step is to create liquid on the surface of Mars. By liquifying the outer core, the planet would be able to create its own dynamo effect and spin like the Earth. There is evidence that Mars had a stronger magnetic field in the past, however, as the planet cooled, it had slowly disappeared. One way we could liquify the outer core of Mars is by setting off a nuclear bomb close to the core of the planet. This would involve a lot of energy and carries the risks of inducing a nuclear winter- which is the opposite of achieving the goal to heat up the planet. 10
Another option is to pass an electric current through the core of the planet so that the resistance would heat up the core, however, this would also require a lot of energy and would need a reliable power source.
A magnetic field would also benefit life on Mars in ways other than just deflecting cosmic waves, and could actually help to stop the erosion of the atmosphere. Currently, the Martian atmosphere is very thin and constantly thinning, which decreases the temperature of the planet.
There are many other possible ways of terraforming Mars, including using large flexible mirrors to reflect sunrays onto the poles, thereby causing them to melt. The poles also contain large stores of CO2 which would also help to thicken the atmosphere. Another way to thicken the atmosphere is by adding large quantities of greenhouse gases (methane and tetrafluoromethane would be most affective) however, this would involve a lot of combustion and is not very feasible, along with decreasing the possibility of humans breathing Martian air. However, this may be overcome in the future through modification to the human genome, enabling us to take out carbon dioxide from the air before respiration.
Terraforming takes large amounts of time. In 2018, NASA’s Maven study estimates that it will take a minimum of 10 million years to double the current atmosphere of the planet using greenhouse gases. Therefore, our best chance for the short term is to build accommodation with strong walls made of regolith (Martian soil) or digging caves to absorb cosmic rays. With this abundance of solutions, there is no possible reason why we should not go to Mars.
Concept art for accommodation made of regolith on Mars
Sources: https://imagine.gsfc.nasa.gov/science/toolbox/cosmic_rays1.html
https://home.cern/news/news/physics/cosmic-rays-throw-surprises-again https://www.aps.org/publications/apsnews/201004/physicshistory.cfm
https://astronomy.com/magazine/greatest-mysteries/2019/07/21-where-do-cosmic-rays-come-from https://home.cern/science/physics/cosmic-rays-particles-outerspace#:~:text=He%20had%20discovered%20cosmic%20rays,the%20way%20up%20to%20uranium. 11
https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Lessons_online/Particle_radiatio n_radioactivity_and_cosmic_rays https://www.space.com/15139-northern-lights-auroras-earth-facts-sdcmp.html https://link.springer.com/article/10.1023/A:1005075813033n
https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Lessons_online/The_effects_of_m agnetic_fields
12
Robomorphic Computing Charlotte Fox
Robotics is one of the most modern forms of technology, but there are still many ways in which it can become more advanced in the future. For example, despite the fact that they are able to move quickly in coded situations due to fast and powerful motors, in more complex situations, robots often have a long reaction time. This is because they are required to ‘make a decision,’ as a response to something that they have been exposed to, which requires time. A solution to this issue is robomorphic computing, which produces a personalised computer chip to reduce the robot’s response time, based on its physical structure and purpose. This is necessary as software improvements alone do not make a large enough difference to see significantly fast results. Robomorphic computing uses hardware acceleration, which is when a specified hardware, such as a graphics processing unit (GPU), is used in order to increase the speed at which the computer works. GPUs have a parallel structure, which allows them to handle a large number of pixels at a time, resulting in a more efficient execution of the specific algorithm. Therefore, robots, which are coded with many specific algorithms, would be able to speed up their reaction time in complex situations with the use of robomorphic computing.
Neuman, the computer scientist who came up with robomorphic computing, plans to automatize the robomorphic computing process, so that instead of having to create personalised hardware for every single robot, the user can enter the physical measurements of their specific robot into the system to create it themselves. The automatized robomorphic computing process would transfer the entered measurements of the robot into mathematical data, and use specified hardware to perform calculations on this data, in order to generate a personalised computer chip. One reason why the quick reaction time provided by robomorphic computing is useful in the real world, is because it opens the possibility for robots to be used for much more intricate and specific jobs. According to Plancher of Harvard University, “for robots to be deployed into the field and safely operate in dynamic environments around humans, they need to be able to think and react very quickly," and therefore they require technology that can handle fast algorithms. An example of one of these jobs is medical care. During the current COVID-19 pandemic, this is extremely important, as it would remove the need for excessive numbers of doctors and nurses to come into contact with their patients. As a result, the risk of the very contagious virus transmitting would be reduced, possibly saving the lives of many high-risk people for whom virus exposure would be fatal. Sources: https://www.sciencedaily.com/releases/2021/01/210121150958.htm https://news.mit.edu/2021/robot-customized-hardware-0121 13
Magnetic Graphene Amélie Gadsby
A team of researchers led by the University of Cambridge have managed to control both the conductivity and magnetism of FePS3 – iron phiophosphate. This is a 2D material, which, when compressed, goes from an insulator to a metal, and therefore a conductor. When newer, high-pressure techniques are used to compress the iron phiophosphate, it can be seen that it transitions into a metallic state whilst still remaining magnetic. The properties of materials can vary depending on the dimensionality – graphite and diamond are both made of carbon atoms but have very different properties.
“But imagine if you were also able to change all of these properties by adding magnetism,” said author Dr Matthew Coak. “A material which Illustration of the magnetic could be mechanically flexible and form a new kind of circuit to store structure of FePS3 information and perform computation. This is why these materials are so interesting, and because they drastically change their properties when put under pressure so we can control their behaviour.” Whilst previous research has already shown that FePS3 becomes a metal at high pressure as well as its structure throughout this transition, “The missing piece has remained however, the magnetism,” said Coak. The new techniques developed by the international team, using specially designed diamond anvils and neutrons which acted as the probe of the magnetism, allowed them to measure the magnetic structure at recordbreaking high pressures and in the metallic state. They discovered that the magnetism survives, which “is unexpected, as the newly-freely-roaming electrons in a newly conducting material can no longer be locked to their parent iron atoms, generating magnetic moments there — unless the conduction is coming from an unexpected source.” said Dr Siddharth Saxena.
If materials are carefully selected, it may be possible to do this without the very high pressure. Moreover, “The thing we’re chasing is superconductivity,” said Saxena. “If we can find a type of superconductivity that’s related to magnetism in a two-dimensional material, it could give us a shot at solving a problem that’s gone back decades.”
This new research could also help scientists understand how conduction in FePS3’s metallic phase works, as well as suggesting that new materials could be engineered that are both metallic and magnetic, which could be essential in developing technologies like spintronics.
Diagram of an electron
Spintronics uses the spin of electrons, as opposed to the charge, in order to encode data. This resolves the issue of electron leakage, which leads to devices being very energy-intensive as they have to recharge the chip 14
capacitors several times per second in order to prevent this. As spin, a type of angular momentum of the electron, is an unvarying property of the electron, it will stay the same and so data will not be lost. However, spin states can be changed by exposing the electrons to magnetic fields or spin transfer torque (when electrons change their spins to match neighbouring electrons), so magnetoresistive RAM was developed as an alternative to capacitors. Magnetoresistive RAM has two ferromagnetic layers with an insulator sandwiched in between. The bottom layer’s spin is fixed by a neighbouring magnet, and the top layer is free so the spin varies depending on external magnetic fields. If the spins are parallel, the computer stores a 1, if they go in opposite directions the computer stores a 0. Iron phiophosphate and other metallic magnetic materials could be used in spintronics to radically change how computers process and store information. Sources:
https://scitechdaily.com/a-new-kind-of-magnetism-formed-by-magnetic-graphene-could-reveal-secrets-ofsuperconductivity/ https://www.youtube.com/watch?v=q3-S5hM-3QY
https://www.techquark.com/2009/08/spinning-electrons-to-store-data.html
15
Physarum Polycephalum- the Slime Mould that Stores Memories Greta Large
In biology, there is often a focus on organisms that directly affect us humans. Pathogens and the study of epidemiology have become ever more important. However, there is so much more to the world of unicellular organisms than just infectious disease. The study of other single-celled organisms could deepen our understanding of the natural world and even help us to combat new infectious diseases. One organism of interest is a slime mould called Physarum polycephalum. It may not look like much, but its innate ‘intelligence’ is astounding scientists around the globe.
Physarum polycephalum is part of the protist family (Wikipedia, 2020) and is a slime mould which seemingly blurs the lines of Image of physarum polycephalum human categorisation. For example, it used to be categorised as a fungus but was later named as an amoeba-like eukaryotic protist. It is amoeba-like in that it spends most of its life as a single-celled organism which contains millions of nuclei and organelles, all contained within one cytoplasm. (Jabr, 2012) It has sparked interest amongst scientists for its behavioural properties. The protist can change its shape depending on its environment and it can ‘move around’ in search of food. It can do this because its structure is made of a complex web of interconnected tubes, which can rapidly form and disintegrate (ScienceDaily, 2021). For example, on a petri dish of agar jelly it spreads itself thin and creates these vein-like, branched structures. Yet on the forest floor, where it is found in the wild, it is often just an orange lump sitting under a leaf (Jabr, 2012). Scientists in the early 2000s from Hokkaido University, having cut up a polycephalum into pieces and placed it in a maze, observed how it could both grow towards other pieces of itself and regroup, as well as grow towards food and away from dead ends (Jabr, 2012).
Image showing the interconnected tubes
However, it does not just end there. Researchers at the University of Munich have found that not only can the slime mould navigate its way towards food, but it can then store information on the food’s whereabouts afterwards, almost like a memory. The question is, how can it store memories if it is a predominantly singlecelled organism with no central nervous system? The answer, they believe, lies within the structure of the organism. When an area of the slime mould encounters a food source, it releases chemicals that travel throughout the organism. These chemicals soften the interconnected tubes of the organism. By doing so the organism’s trajectory is directed towards the food source. (ScienceDaily, 2021). However, these changes in the 16
properties of the tubes cause for a change in the structure of the organism. To be exact, it affects the tube diameters. The tube-softening chemicals that are released when it encounters food enlarge the diameter of the tubes which they travel through. Therefore, when the organism encounters food in these places again, the enlarged tubes have a higher capacity for flow-based transport (Kramar and Alim, 2021). Hence, its previous encounters with food sources will affect its future movement.
Physarum polycephalum is a peculiar organism but one that could inspire many initiatives that could aid us in everyday life, despite the organism itself having seemingly little impact on us humans. Karen Alim from the university of Munich says that he can envisage that the research will help to design new ‘smart’ materials and even new robots which can navigate through complex environments (ScienceDaily, 2021). There is so much more to discover about unicellular organisms and we are only just beginning to realise how weird and wonderful they can be. Sources:
Wikipedia. (2020). Physarum polycephalum. [online] Available at:
https://en.wikipedia.org/wiki/Physarum_polycephalum [Accessed 1 Mar. 2021]. Wikipedia. (2021). Plasmodium (life cycle). [online] Available at:
https://en.wikipedia.org/wiki/Plasmodium_(life_cycle) [Accessed 1 Mar. 2021]. Jabr, F. (2012). How brainless slime moulds redefine intelligence. Nature.
ScienceDaily. (2021). A memory without a brain: How a single cell slime mould makes smart decisions without a central nervous system. [online] Available at:
https://www.sciencedaily.com/releases/2021/02/210223121643.htm [Accessed 1 Mar. 2021]. Kramar, M. and Alim, K. (2021). Encoding memory in tube diameter hierarchy of living flow network. Proceedings of the National Academy of Sciences, [online] 118(10). Available at: https://www.pnas.org/content/118/10/e2007815118 [Accessed 1 Mar. 2021].
17
Parkinson’s Reversing Neuron Grafts Fope Akinyede
On March 1st, 2021, researchers at the University of Wisconsin-Madison announced that they had been able to successfully reverse some of the symptoms associated with Parkinson’s disease in monkeys using their neuron grafts.
Parkinson’s is a progressive nervous system disorder that is caused by the loss of neurons in the substantia niagra. It is characterized by a variety of physical symptoms that affect the movement of a person with Parkinson’s. The main symptoms are involuntary shaking of specific parts of the body, slow movement, and stiff, inflexible muscles. Many of the symptoms, such as impaired movement, are due to the loss of dopaminergic neurons – the main source of the hormone dopamine in the central nervous system as dopamine plays a huge role in the regulation of movement in the body.
Simplistic diagram showing how Parkinson’s disease develops
A common medication prescribed to those suffering from Parkinson’s is Levodopa (L-DOPA). It is a precursor of dopamine and therefore, when absorbed by neurons in the brain, is converted into dopamine, thus increasing dopamine levels. Most people with Parkinson’s eventually take levodopa as it is one of the best ways of treating the symptoms. However, over time it becomes less effective as it does not prevent the progressive loss of dopaminergic neurons. The disease continues to progress, and long-term use of levodopa has been found to be a cause of dyskinesias (uncontrollable, jerky muscle movements) and deteriorating motor skills. The research team at UW made neurons from induced pluripotent stem cells (iPSCs) from the monkeys’ own bodies (autologous transplant). By extracting the cells from the monkeys, themselves, this approach avoided rejection from the monkey’s immune systems, because the body does not recognise the cells as foreign, which is a key step toward treatment for human Parkinson’s patients. Scientists have used cells from foetal tissue before to treat later-stage Parkinson’s, however this approach is not very effective as it is limited by the availability of useful cells and complications with the patients’ immune systems.
In the experiment, researchers gave half of the monkeys an autologous transplant into the striatum and the other half, an allogenic transplant (their cells were received from other monkeys) also into their striatum. All the monkeys were administered with a neurotoxin in the rhesus macaques, which is normal practice for inducing Parkinson’s-like damage for research. The difference was stark at six months. The autologous monkeys were making significant improvements and were moving more and with ease. Within a year, their dopamine levels had doubled and tripled. On the other hand, the allogenic cells showed no last improvements in motor skills or dopamine levels. The axons of autologous graft were longer and more intermixed with the surrounding tissue than the allogenic grafts. Unlike the autologous grafts, the allogenic grafts did not spread further than the striatum because the body recognised them as foreign and they were attacked by the immune system. This meant that the allogenic graft was walled off from the rest of the brain which prohibited them from renewing contact with other areas of the brain such as the area that regulates our emotions. This area is 18
important within Parkinson’s because depression and anxiety are some of the main non-physical symptoms. Symptoms that resemble depression and anxiety in the monkeys such as pacing and disinterest in others, subsided after the autologous grafts grew in.
Since monkeys are such close relatives of humans, this result is extremely promising for future Parkinson’s disease treatment. SuChun Zhang, one of the lead researchers at Wisconsin-Madison, is hopeful that the results are promising enough to begin work on human patients soon. If it works, this approach could change the lives of millions of Parkinson’s patients, both present and future. Dr Zhang and his research team at University of Wisconsin-Madison
Sources: https://parkinsonsnewstoday.com/2021/03/05/brain-cell-transplant-reverses-parkinsons-symptomsmonkeys-study/
https://www.mayoclinic.org/diseases-conditions/parkinsons-disease/symptoms-causes/syc-20376055 https://www.nhs.uk/conditions/parkinsons-disease/
19
The Placebo Effect: The Science and Ethics Behind the Mystery Maaira Khan
The placebo effect is a strange yet fascinating medical phenomenon- in fact, the whole prospect of being able to heal oneself through the belief that one is being healed has been known for a millennium (1). Studies have shown that, though placebos are unlikely to be able to lower cholesterol or shrink tumours, it is much more effective for symptoms influenced by the brain such as the perception of pain, or cancer treatment side effects such as nausea. Overall, the effect doesn’t exactly cure, but does make the patient feel better.
All clinical trials will have a placebo group
For this reason, the placebo effect is always used in clinical trials. In early trials, the progress of patients who took a drug would always be compared to the progress of a control group who were not taking the drug. However, since realising that even the act of taking a tablet in itself can lead to improvement, a third placebo group who is prescribed tablets without any form of active ingredients is always necessary (2). If the response from the drug is not any different than that of the placebo (even if both lead to improvements) the drug is rendered ineffective.
Nevertheless, more recently experts have concluded that the matter is not as simple as this. During studies of these sorts, patients will have to go to clinics and be monitored frequently, as well as being prescribed with many different ‘exotic’ drugs. These complex environmental factors will also influence a patient’s perception of their symptoms as they feel as though they are getting a lot of care (1).
Interestingly, a 2014 study published in Science Translational Medicine tested patients’ reactions to migraine medications. While one group was prescribed an effective drug with its name written on the label, another group was given a placebo with bottles labelled ‘placebo’- the patients knew that their ‘medication’ contained no active ingredients. But still, it was found that the placebo was still half as effective as the drug for pain relief. Researchers suggested that perhaps simply the act of taking a tablet, an act associated with improving health, could lead to beneficial results.
So, what exactly causes these psychological effects? This has been a long-standing question; however, a statistical analysis published in Nature Communications has been able to uncover some of the answers to placebo analgesia (3), which are placebo treatments that are used for pain relief (4). Across the study, many participants stated that they felt less pain. However, what it was necessary for researchers to work out was whether the placebo was actually causing a meaningful response in the brain and changing how an individual can construct the very perception of pain, or whether it was merely changing how a person thinks about pain afterwards. In essence, was a patient actually experiencing less pain?
The researchers were able to confine the placebo effect to specific parts of the brain such as the thalamus and basal ganglia. The former acts as an entrance for sensory input such as sights and sound and has different nuclei which process these different types of input. The study showed that sections of the thalamus that were most important for the sensation of pain were most strongly impacted by the placebo. Parts of the 20
somatosensory cortex (important for processing painful experiences) were also affected. Effects could also be seen in the basal ganglia, which play an integral role in connecting pain and other such experiences into actions. Moreover, it was seen that the treatment reduced activity in the posterior insula, which is involved in constructing the experience of pain. In fact, this is the only part of the cortex in which pain can be stimulated. Essentially, the results gave evidence that the pathway of pain construction was affected by the placebo.
Image showing the inner boundaries of the lobes of the cerebral cortex However, it is also important to take into account ethical considerations of the clinical use of placebo treatment. The ethical issue is not that the patient is receiving ‘useless’ medication- after all, studies have shown that placebo treatment is highly effective- but more so that a doctor is required to hide information from their patient, a violation of the right of a patient to be truthfully informed of their treatment; patient autonomy is not taken into account. However, many also argue that treatment is not all about “biomedical pursuit” (5), but that doctors also intervene in a much more personal and sensitive way. With this in mind, it could be argued that the use of placebo treatment can only be considered “deception” if a more outdated Cartesian view on bodily illness being untreatable through emotional means is applied. Moreover, as outlined earlier, telling the patient that they are receiving a placebo does not render the treatment ineffective, so even patient autonomy can remain securely intact. As always, if a patient is asked the name of the medication, they must be told; if they ask how it works, they must be told; if they do not wish to receive this treatment, it is well within their rights to decline. To conclude, placebo treatment has always been a mysterious, yet exciting, branch of medicine through the ages, but as more studies continue to be carried out, we are beginning to uncover more the neuroscience behind what exactly is going on when this phenomenon occurs. Of course, clinical use comes with ethical challenges, but good medical practice should easily be able to render the use of such treatment ethical and effective, without taking away a patient’s autonomy or right to decline treatment.
Sources:
(1) https://www.health.harvard.edu/mental-health/the-power-of-the-placebo-effect
(2) https://www.medicalnewstoday.com/articles/306437#what-is-the-placebo-effect 21
(3) https://www.technologynetworks.com/drug-discovery/news/a-detailed-look-at-the-neuroscience-ofplacebo-effects-346206 (4) https://bnf.nice.org.uk/treatment-summary/analgesics.html
(5) The Ethics of the Placebo in Clinical Practice.P. Lichtenberg, U. Heresco-Levy and U. Nitzan.Journal of Medical Ethics , Dec., 2004, Vol. 30, No. 6 (Dec., 2004), pp. 551-554 Published by: BMJ
22