Vector Magazine, 5th Edition, November 2022

The SPS STEM Journal

Alexander Apkarian Editor in Chief

Deputy Editors

Noah Whale

Zak Farazi

Vikram Bhamre Astronomy

Biology

Biotechnology

Book Reviews

Chemistry

Computer

Science Engineering

Kai Philipose Ryo Kusakari

Thomas Hallé Ynon Weiss

Yuxi Liu

Alexis Andronikos Luca Viviano Dom Yap Harishan Ganeshan

Charles Calzia Rahul Marchand

Environmental Science Frederick Dehmel

Gabriel Treneman Shashwat Sangwan Medicine

Maths

Leo Wen Oliver Milroy Goulding

News

Physics Psychology

Marco Cina Rabin

Adrien Durantel Teddy Onslow

Shivan Arora Varun Vashisht

Editorial

Welcome, readers, to the fifth edition of Vector,theSt Paul'sSTEM journal.It hasbeen a privilege to lead a large team of talented peers in collaboration with our dedicated teachers.I would like to sincerely thank all of thoseinvolved

This year?s edition was conceived and edited in a somewhat unconventional fashion; I began the work in London and completed it in Californiaduringa10 week research stint Although this complicated logistics, it strengthened the publication Working in a laboratory enabled me to bounce ideas off several highly esteemed researchers who wereabletoprovideinvaluablefeedback.

The title, Vector, has always fascinated me Derived from the latin ?Vehere? , meaning to carry, its scientific usage varies according to discipline In mathematics, physics, and engineering,avector conveysmagnitudeand direction In biology it denotesavehicleused tocarry foreignmaterial intoacell

In an increasingly complex and interconnected world, the most profound scientific advancements will come from interdisciplinaryapproaches.

We see evidence of the significance of multidisciplinary perspectives all around us The discovery of the DNA double helix was only fully harnessed due to parallel developments in computational power, information theory,and powerful algorithms. Likewise, the record breaking speed of vaccine developmentsduring Covid required breakthroughsin both biology and computer science ? AI programs were used to design mRNA molecules

Whilst some will confine this multifaceted approach to within STEM disciplines, the scientific world would greatly benefit from

greater integration with literature and philosophy. Effective communication in science is of paramount importance if the public are ever to actualize the extent of ground breakingdiscoveries. Moreover, it is critical that the fidelity of scientific work isheld to the highest possible standard ? both to advance science and to maintain the public?s trust Famous missteps include the false claims about cold fusion in the 1980s, Andrew Wakefield?s infamous paper on MMR vaccines, and the cancer causingpotential of powerlinesin the 1990s.

A lack of rigour and skilled communication within the scientific field has, in great part, led to the ?irreproducibility crisis.? Reproducibility is key as it allows peers to review, confirm, and build upon work The universal aim to publish papers soon after a discovery (driven by a ?publish or perish? environment) should be balanced with the quality of scientific research and the clarity of papers Below istheresult of ameta study concernedwithirreproducibility inscience

In order to effectively combat this?crisis?,we must foster interdisciplinary and rigorous environments The separation between STEM and humanities should not act as a closed, but rather a permeable, barrier, allowing for the sharing of ideasand themes, ensuringeffectivescientificcommunication.

Astronomy

Astronomy Society: Observing The Sun page5

Biology

Myostatin and Its Role in Doping page7

The Key to Eternal Youth?The Technique that Rewound the Age of Skin Cells by 30 Years page9

Clash of the Titans: Spinosaurus vs Tyrannosaurus page11

Mendel's Discoveries in the Understanding of Complex Diseases page13

Biotechnology

Mycoremediation: How Fungi Can be Used to Clean the World page15

Lipid Nanoparticles: A New Era of Vaccines page16

Book Reviews

The Emperor of All Maladies By Siddhartha Mukherjee page19

A Brief History of Time By Stephen Hawking page20

Chemistry

The Catalytic Condenser Chameleon Device: Appreciating the Value of Metal Catalysts page22

Contents

The Chemistry Behind Acne page24

The Biochemistry of Coffee page26

Computer Science

The Illusion of the Third Dimension and the Tropes of Modern First Person Shooters page28

How does a Bayesian Neural Network Model Differ from a Traditional Point Estimate Neural Network? page29

The Travelling Salesman Problem page31

Engineering

"EJECT! EJECT!" page33

The Future of the Factory page34

Environmental Science

Constructing a 'Simple' Climate Model page36

Mathematics Catalan Numbers page38

A Combinatorial Proof of Wilson?s Theorem page39

Medicine

The Future of Artificial Intelligence in Medicine page42

A Life for a Life: Xenotransplantation page 43

Human vs Disease page 45

News

Can Mistletoe Berries be Used as a Superglue? page 46

How do Hypergiants Die? page 46

A New Black Hole? page 47

Do Mummies Still Contain Ancient Strains of Bacteria? page 47

Physics

The Doppler Effect page 48

Quantum Computing: Separating Fact from Myth page 49

Centripetal Force page 51

Psychology

What is Addiction? page 53

Does Language Affect the Way in Which We Think? page 54

Astronomy

Astronomy Society: Observing the Sun

Danny Cui

In June of 2022,right the end of the summer term, the Astronomy Society completed its first ever observation of the Sun. This viewing was successful and we were even able to see some of the details on the Sun's surface ? most notably sunspots and solar filaments.

But what are sunspots and solar filaments? How do solar activities like these affect us? How does the equipment used to observe theSunwork?

Solar filaments are structures of plasma and magnetic fieldswhich extend outwardsfrom the photosphere (the deepest observable region of the Sun?ssurface) They often form in the shape of a loop owing to their underlying magnetic field and can extend from 50,000 to 70,000 km into the corona (the outermost part of the Sun?s atmosphere) Giventhat their plasmaismuch cooler than that of the corona, solar filaments usually appear as dark line segmentsontheSun?ssurface Sunspots, as the name suggests, are dark spots on the surface of the Sun. They are minima of temperature on the Sun?s surface, caused by concentrations of magnetic flux, which prevent convection currents in the Sun from transferring heat to their surroundings. Sunspots have two main structures? theumbra(acentral region)and the penumbra (a surrounding region) The umbra is the darkest area of the sunspots, and the coolest area ? roughly around 2,700°C to 4,200°C This is because the magnetic field is at its strongest. The

surrounding penumbra is brighter and has a temperature of around 5,500°C Sunspots often come in pairs of opposite magnetic polarity Below is a photo that was taken during our observation It illustrates a solar filament in the bottom right corner, apair of sunspots, and the curling of the sunspots' surroundings with the pattern of their magneticfields.

Sunspots form where strong magnetic fields emerge from the Sun?sinterior.These strong magneticfieldscatalyseother solar activities which accompany periods where a large number of sunspots appear. These activities include solar flares, where intense localised electromagnetic radiation on the Sun's atmosphere erupts owing to acceleration of charged particlesin theSuncaused by stored magnetic energy in the sun?s atmosphere; coronal massejections,wherelarge amounts of plasma are released due to intense magnetic activity on the Sun into the solar

wind; and other solar phenomena. These periodsof intense solar activity, referred to as?solar maxima?,occur in regular periodsof roughly 11 years. This is called the solar cycle,wherethemagneticpolarity of theSun flipsperiodically

Some coronal mass ejections (CMEs) result in large amounts of plasma travelling towards the Earth, carrying with them a strongmagnetic field.The shock wave of the travelling plasma compresses the Earth?s magnetic field, and its magnetic field interacts with that of the Earth's, storing energy in the Earth?smagnetosphere This is called a geomagnetic storm Energy in the magnetosphereincreasesplasmamovement, increasing current This energy can also induce electric currents in our power grids and other grounded conductors. This can cause instability in power transmission networks and result in the burning out of transormers. Given our dependancy on electricity,thisishighly problematic However, solar activity can also manifest itself in stunning ways. For CMEs which exude smaller amounts of plasma travelling towards the Earth, the plasma, being charged particles,is deflected by the Earth's magnetic field and towards the north and south poles These charged particles then collide with oxygen and nitrogen atoms, releasing energy in the form of colourful light,creatinganaurora

We observed these details on a telescope equipped with ahydrogen alphafilter,which allows for only a specific range of light wavelengths. This is critical as it limits the light collecting power of the instrument, making the image observed safe to the eye We also captured images in calcium-K or visible light to highlight different featuresof the sun We first captured thousands of frames of the Sun through a monochrome camera with the shortest possible exposure time For each image, the exposure time is kept to a minimum to prevent any blurring

owing to the atmosphere. Subsequently, we used a stacking software which used a point of reference in the image to align and combine the frames. Usually, only the best 50% of frames are used, as the blurred frameswill only downgradethefinal product. The image is then sharpened in image processing software To do this, a histogram of the data is manually altered to enhance the detail on the sun, after which a noise reduction algorithm is applied Finally, the individual red,green and bluechannelsof the image are tweaked to artificially give colour This is up to the preference of the user, and some people like darker, redder versions of theSunwhileothersprefer alighter edit

If you are interested in extraordinary activities related to astronomy like this one, be sure to email Dr Gane, or come to P4 on Tuesday lunchtimes at 1:00 pm Lastly, the astronomy society wants to thank our financial supporters who have given us the money tobuy theequipment.

Biology

Myostatin and I ts Role in Doping

Hugo Lefranc

Doping is now a global problem for major sporting events Sports federations, led by the International Olympic Committee, have, for the past half century, unsuccessfully attempted tohalt itsspread It wasexpected that educational programs, testing, and supportive medical treatment would decrease this behaviour Unfortunately, this has not been the case. In fact, new, more powerful, and undetectable doping techniques are now abused by athletes Simultaneously, even more sophisticated distributionnetworkshavedeveloped

Myostatin is a molecule discovered in 1997 by a team working on the Transferring Growth Factor B (TGF B) hormone family usingatechniquecalled degenerativePCR It signals through the activin receptors and functions as a negative regulator of skeletal musclegrowth.

The TGF-B group ran numerous in vitro functional assays using mouse models The knockout mice without functional myostatin survived but with an altered biology that clearly pointedtotheroleof myostatininthe body:they had200%moremusclemassthan the control mice owing to an increase in the size of muscle fibres and in the number of myocytes A similar phenotype is seen in some breeds of cattle known to be genetically ?doublemuscled?,for examplethe Belgian Blue. It was subsequently noticed that a five year old boy who had a dramatic increase in muscle masswasfound to have a defect in his myostatin gene. Following this, interest in myostatin significantly increased. Athletes and bodybuilders in search of

performance enhancing drugs were particularly fascinated by it There were many questions being asked, but most importantly, could the role of myostatin be useful intheworldof doping?

The first thing to note is that unlike mTOR (the start button for muscle growth), myostatin signalling isspecific to the muscle; thisisagoodstart for any prospectivedopers as it means that a molecule that targets myostatin will only affect the desired part of the body Also, the myostatin pathway encompasses a range of possible doping targetsother thanmyostatinitself

To become effective in muscle cells, myostatin needs to be modified by other proteins These proteins, called proteases, degrade myostatin, making it an optimum size for activity.Onceactive,myostatin binds to proteins on the muscle cell surface that then bind to the TGF B hormone receptors Myostatin binding activates these receptors, allowingthem to phosphorylatetwo proteins in the cell called SMAD2/3 and SMAD4. These then bind to the nucleus and to specific parts of the DNA ? and by an as of yet unknown mechanism ? switch off muscle protein synthesis This illustrates the

complex process associated with protein synthesis supression in muscles It also demonstratesthat there aremutlipletargets for myostatinrestriction.

by cachexia, a symptom of cancer that causes the loss of muscle and fat despite adequate nutrition. Some studies in mouse models suggest that myostatin inhibition may prevent cancer related muscle loss in both lung and skin cancer (melanoma). This suggeststhat myostatin inhibition should be further researched for the prevention of catexia-relateddeathsinhumans.

Since its discovery, pharmaceutical companies have produced myostatin ? inhibiting drugs to treat diseases such as muscular dystrophy However, this means that such drugs are available to athletes and bodybuilders who would look to consume these to improve their muscle mass ? a key attribute in many sports One such drug produced is Stamulumab. This is a G1 immunoglobulin antibody which binds to myostatin and preventsit from binding to its target site, thus inhibiting the growth limiting action of myostatin in muscle tissue In 2019 it was added to the World Anti Doping Agency's list of prohibited drugs as it was feared it gave competitors too much of an advantage. However,aswith most prohibited drugs,this doesn? t remove the threat of usage, and as a result it is still being consumed throughout theworldby athletes

But what does myostatin inhibition actually do?Aswesaw earlier,itsmain effect isthat it reducesmusclelossduringinactivity and can also help build muscle However, scientists also believe that myostatin inhibition may prevent muscle loss from diseases such as muscular dystrophy In addition,over 20%of cancer deaths in human patients are caused

However, myostatin inhibition does not come without side effects Firstly, increased muscle growth will lead to an increased risk of injury owing to stress on the muscle fibres This may be especially true for individuals using myostatin inhibitors as workout supplementsinstead of asamedical treatment for muscular dystrophy or other disorders. Other possible side effects include increased chanceof tendon rupture, heart failuredue to inflamed cardiac muscle, and rhabdomyolysis(a breakdown of muscle fibresthat often leadsto kidney failure) It is clear that myostatin inhibition can play a critical role in doping. The plethora of targets for myostatin signalling supression, along with its various benefits, makes myostatin inhibition a very attractive process to potential dopers However, this has side effects Nonetheless, a survey conducted by Dr Robert Goldman claims that over 50%of athleteswould take a drug that guaranteed them unlimited, undetectable sporting victories for five years, even if it was followed by instant death Thus, myostatin could be a very attractivetarget for dopinginthefuture.

The Key to Eternal Youth? The Technique that Rewound the Age of Skin Cells by 30 Years

Kai Philipose

Crackingthecodeof why weageandhow to reverse it has been the Holy Grail for scientists, and, in recent years, for billionaires seeking to literally buy more time to spend their ever increasing mountains of wealth. Luckily for them, as well as us, a team of researchers from the Babraham Institute in Cambridge seems to havebrought usonestepcloser tothisgoal.

What is ?ageing??Ageing can be defined as the gradual decline in organismal fitness that occurs as a consequence of the molecular ?hallmarks? of ageing: telomere attrition, genetic instability, epigenetic and transcriptional alterations, and an accumulation of misfolded proteins Thus, many of the symptoms we associate with ageing are a direct consequence of these molecular hallmarks For example, loose wrinkly skin iscaused by the dysfunction of skin fibroblasts in the dermis. With age, they produce less collagen, elastin, and growth promoting factors that create the foundation of a healthy, plump epidermis (thevisiblelayer of theskin)

Sohow might wereverseageing?

Perhaps the idea of turning back time on our cells seems preposterous, however, the resetting of the ageing clock is a frequent, deeply installedprocessthat iscrucial tothe nature of life: it occurs with every fertilisation event For humans,thisinvolves the fusion of two cells, a sperm and an egg, each of whose chronological age is measured in decades, to give rise to a zygote which somehow has no trace of the parental cells' age Although one might make the argument that the mechanism by which these germ cells fuse and then rejuvenate is specific and so not replicable

in other cells of the body, this was be disproven by Dr John Gurdon?s pioneering experiment in1962.

Dr Gurdon showed that differentiated nuclei from tadpole intestinal or muscle cells could be transferred into enucleated Xenopuseggs and give rise to mature and fertile male and female frogs that showed no signs of prematureageing.Just likethefused nucleus of the sperm and egg during fertilisation,the somatic nucleus was reprogrammed and any hallmarksof ageing were reset.Therefore,in principle, there must be a mechanism which we could utilise to reverse the molecular attributes of ageing and phenotypically rejuvenatesomaticcells

Enter YamanakaFactors

Discovered by Shinya Yamanaka in 2006, these four transcription factors (Oct3/4, Sox2, Klf4, c Myc) can turn differentiated adult cells into pluripotent stem cells in a process called induced pluripotent stem cell (iPSC) reprogramming iPSC reprogramming has shown to be able to reverse many age associated changes, including telomere attrition and oxidative stress Unfortunately, however,it also results in the lossof original cell identity and so function To avoid this, researchers from the Babraham Institute decided to takeanother approach,wherethe Yamanaka factors are only expressed for short periods of time This novel strategy called transient reprogramming was able to achieve a ?robust and very substantial rejuvenation? of around 30 years in fibroblastswithout lossof cell identity.

iPSC reprogramming consists of three phases: the initiation phase (IP), where somatic expression is repressed; the maturation phase (MP), where certain

pluripotency genes become expressed; and the stabilisation phase (SP), where the complete pluripotency program is activated. Previous methods of transient reprogramming had only reprogrammed within the IP, but researchers were able to show that further reprogramming up to the MPmay achievegreater rejuvenation.

In their method,Babraham researcherstook fibroblasts from three middle aged donors (aged 38, 53, and 53) and then reprogrammed their fibroblasts for different lengths of time (10, 13, 15, 17 days) using a ?reprogramming cassette? that encoded Oct4, Sox2, Klf4, c Myc to ensure all four Yamanakafactorswereexpressed

The efficacy of the reprogramming was determined by measuring changes in the different molecular hallmarks of ageing through methodssuch asexaminingavariety of ageing ?clocks? as well as looking at restoration of function in individual cells Ageing ?clocks? distinguish biological age fromchronological ageand areimportant for identifying genetic and environmental factors that influence the ageing process. In this experiment, a BiT age clock was used to investigate rejuvenation in the transcriptome, whilst an epigenetic clock was used to find evidence of epigenetic rejuvenation Results pointed to a 30 year quantitativerejuvinationinboth.

The function of these reprogrammed cells was also considered, as they should both appear and behave like young cells. For example, production of collagen is a major function of fibroblasts, so the expression of all collagen geneswere examined beforeand after reprogramming They found that collagen I and IV (proteins downregulated with age) were restored to youthful levels after transient reprogramming Fibroblasts arealso involved in wound healingresponses by movinginto areasthat need repairing(we heal slower with age due to the reduction in the cell migration speed of ageing

fibroblasts) Transient reprogramming improved the median migration speed, although there some speeds were unaffected Overall,the resultsshowed that maturation phase transient reprogramming (MPTR) rejuvenates multiple molecular hallmarks of ageing, including the transcriptome, epigenome, functional protein expression, and cell migration speed Intriguingly,it wasalso found that 13 days of reprogramming was the ?sweet spot? and longer time periods diminished the extent of transcriptional and epigenetic rejuvenation.

The mechanism behind their successful transient reprogramming is still not fully understood and there remain a great many challenges when it comes to therapeutic applications Only around 25% of the cells were successfully reprogrammed and other hallmarks of ageing such as telomere attrition were unaffected Therefore, it is perhapstoo early to say that we have found the silver bullet to end ageing, but we may have taken one small step closer to finding themythical Fountainof Youth.

The Fountain of Youth by Lucas Cranach

Clash of the Titans: Spinosaurus vs Tyrannosaurus

Aiken Lau

A one minute fight in Jurassic Park III immortalised the clash between the Spinosaurus aegyptiacus and Tyrannosaurus rex. One of the only incidents in popular culture in which the King of the Dinosaurs was promptly dethroned. However, this fight,involvingtheSpinosaurussnappingthe Rex?s neck with its forelimbs, is nowhere near thetruth.With that aside,let?sdiveinto the facts behind this Cretaceous (NOT JURASSIC)clash

shaped tail packed with muscle similar to a crocodile?s; this served as both a strong weapon to sweep potential targets off their feet, and an aid for aquatic locomotion (perfect for itshome on the marshy coastsof CretaceousEgypt).

Our first contender, the Spinosaurus, lived around 90 million years ago and was a semi-aquatic predator. Its most impressive prey include the eight metre sawfish, Onchopristis Spinosauruses could grow up to 17 18 metres long and exceed 7 tons in weight It isthe largest carnivorousdinosaur ever discovered. The giant sail on its back would most likely have been for intimidating rivalsand thermoregulation It also had long crocodilian jaws with conical teeth. Small pores at the ends of the snout would have been used for sensingvibrationsin thewater ? a great tool for seizing fish. Its viciously large claws on its muscular forelimbs were also adept at killing fish and land animals alike. Despite the movie dinosaur having a conical tail, the Spinosaurus was recently discovered to have had a broad, paddle

This habitat was one of the most dangerous places to live in Earth?s history The Spinosaurus coexisted with another large carnivore, Carcharodontosaurus (which was also bigger than the T Rex) Although it seldom fought with Carcharodontosaurus as the latter mainly tackled larger prey (like other dinosaurs) on land. But, this does not mean they never clashed. They would encounter each other regularly in the dry season as Spinosaurus? aquatic hunting groundsdried upintheheat forcingit tohunt land animals This suggests that the Spinosaurus, despite being specialised to eat fish, was more than capable of holding its ground against large dinosaurs These confrontations often turned in the Spinosaurus? favour due to its large sail, which intimidated other opponents and won askirmishwithout asingleblow.

The Tyrannosaurus rex could not have been more different This prehistoric tyrant lived in the Late Cretaceous period, 67 65 million yearsago,preferringthecomfort of dry land This 12 metre North American juggernaut was shorter than the Spinosaurus, but was the heaviest of all known carnivorous dinosaursat around ten tons.A robustly built predator, the T Rex had a broad head and neck, and serrated teeth as long as bananas

The jaw packed ahuge bite force of up to 6.5 tons,which isthestrongest biterecorded for all land animals and could crush a car This

enabled it to harness?puncture-pull feeding? , which involved the predator's biting deep into its prey, puncturing the insides Strong neck muscles would then pull back the head and rip out a huge mouthful of flesh, bone, and organs to inflict critical damage, killing the unfortunate victim with shock and blood loss This unique method of feeding was exclusiveto theTyrannosaurusand itsfamily as it requires teeth rigidly attached to the jaw (otherwise all the teeth would be unceremoniously pulled off when the animal attempted it) and robust neck muscles to pull back the huge head while itsteeth were embedded deep in the flesh It developed this way of feeding to pierce the armour of large herbivores, like its equally iconic contemporaries Triceratops and Ankylosaurus. Notably, recent research has suggested that this predator hunted in family groups, not just the men, but the women and the children For them hunting wasafamily excursion!

So what would happen if these two prehistoricpredatorsmet?

Short answer:They wouldn? t evenfight

In the first place, they would not have even come into contact as they lived on different continents 40 million years apart. Even if they had met, there would have been nothing to fight over, as they occupied different ecological niches and shared different forms of prey At most, they would have displayed threats to each other (the Spinosaurus would probably have won this with its gargantuan size and intimidating sail), instead of going into a fully fledged fight, which could have crippled, if not outright killed, both creatures Remember, these creatures aren? t movie monsters, they are animals that aim to conserve energy. As such,aimlessfighting would certainly not be

beneficial for either party.

If coaxed to fight, the outcome would have been heavily dependant on the setting On dry land, whilst the Spinosaurus had more experience in dealing with large carnivores like Carcharodontosaurus, it would find it harder to launch a surprise attack owing to its vast size and sail The T Rex would most likely reign victoriousin thissituation,taking advantage of its powerful jaws evolved to grip and tear large prey, while the Spinosaurus? jaws and claws were more suited for fish. However, in any remotely aquatic habitat, it would be a completely different story. The Spinosaurus was the undisputed king in the water, easily propelling itself in the water and detecting itsrival?slocationwiththeporesonitssnout.

The T. Rex, would definitely be outmanoeuvred by its semiaquatic rival Funnily enough, the T. Rex would have been preoccupied tryingnot to drown,rather than focusingonthefight

To conclude, between these two reptilian behemoths, there is no clear winner Each one had its own strengths and ecological niches, making the outcome of a potential fight heavily dependant on the location However, it should be noted that research into theseapex predatorsisstill ongoingand new discoveries may be made which could dramatically shift our understanding of either dinosaur Who knows, perhaps newfound knowledge may shed light on the conflict of thesetwoprehistoricbeasts.

Mendel's Discoveries in the Understanding of Complex Diseases

Yuxi Liu

With roughly 80% of all rare diseases resulting from genetics, 400 million people worldwide suffer from 7,000 distinct Mendelian disorders However, the genetic basis for over half of these remains elusive Complex disease phenotypes are only partially represented by our genomic sequences; under the influence of external factors, such disorders arise from not only heredity, but environment, mutation, lifestyleand evolution ? it isthepathological confluenceof DarwinandMendel.

strand, and the exact number of repeats will determine the gene?s penetrance ? in most severe cases, repetition exceeds 41 codons. Roughly 50% of affected parents?offspring will suffer from HD due to the presence of a dominant allele, as stated by Mendel?s principleof uniformity

Mendelian patterns of inheritance can be used to study the patterns of inheritance of single gene disorders across a family pedigree. One such example being Huntington?s Disease (HD) ? individuals with a single mutant autosomal dominant huntingtin gene (HTT) are likely to suffer from HD in their late 30s, resulting in cognitive decline and involuntary movements caused by the ?triplet repeats? mutation Extra repetitions of the codon ?CAG? are added to the polynucleotide

Although HD may purely be due to gene mutations,many disordersmay be alleviated or exacerbated by lifestyle changes and environmental alterations. Commonly known as ?Asian flush? , the accumulation of acetaldehyde causes dilation of facial blood vessels resulting in redness ? a condition present amongapproximately 40%of Asians Studies uncovered a mutation within the ADH1C gene that codes for the gamma subunit in alcohol dehydrogenase (ADH), an enzyme which catalyzes the rate-determining step of ethanol metabolism However, caucasians are less likely to inherit said deficiency owing to genomic differences caused by environmental factors In the 18th century among most European countries, 2 3% alcohol was the main source of fluid intake due to lack of sanitary water Over time, gene adaptations have thus led to more ADH productionwithin theseindividuals.

Nevertheless, discoveries regarding the genetic nature of illnesses offer minimal information about the genes themselves; phenotypic variability in disease severity occurs even amongst monozygotic twins with an identical primary mutant gene As shown by Gaucher Disease (GD), its clinical classification can be categorized into type I

(non-neuronopathic), type II (acute), and type III (sub acute); the first of which, was found to be predisposed to Parkinson?s Disease (PD), whereas types II and III were characterized by neurological impairment. Although the clear cause of PD is still unknown,it?s certain that the mutant GBA1 gene in GD isa prevalent genetic risk factor in the exemplification of PD Detailed investigation of interactions between genes would certainly provide aspiration towards the complete understanding of complex polygenic diseases. Although projects such as the Encyclopedia of DNA Elements (ENCODE) and several genome wide association studies (GWAS) have mapped out the entire human genome in an orderly fashion, the functions of non-coding introns withinthedoublehelixremainamystery.

To fully understand the variability of phenotypic expression in Mendelian disorders, it?s necessary to analyze the entire genomic information of affected individuals. The completion of the Human Genome Project in 2003 has revolutionised scientists?approach to complex diseases by providing new insights into navigating disease causing mutations An example being single nucleotide polymorphisms (SNP) ? single DNA base pair changes used asgeneticmarkersfor assessingdiseaserisk and associated mutations. When they occur in the functional region of a used protein,or in higher frequency in affected vs unaffected subjects, it may be an indication that SNPs are physically close to the disease causingmutation They may beseen as genetic signposts, or an internal GPS systemfor thegenome

0.025% can be altered by our modern pharmacopeia The presence and feasibility of gene sequencing technology has led to a lasting war of personalized medicine against complex diseases. Recent success of clinical trials for Chimeric Antigen Receptors Cell Therapy (CAR-T) in the treatment of acute lymphoblastic leukemia is sure to act as a stepping stone towards our ultimate victory in thisbattle.Regardlessof the rarity of such diseases, we must increase our financial motive and further our research into the mechanisms behind genomic expression in order to stand a chance of curing life threateningillnessessuchascancer

Out of the several million biological molecules present in the human body, only

Biotechnology

Mycoremediation: How Fungi Can be Used to Clean the World

Ynon Weiss

As the world continues to industrialise and develop,environmental and health concerns over chemical waste are escalating Traditional physicochemical methods for waste treatment are often effective, but typically onerous to scale up, unsustainable, andfrankly expensive.

Bioremediation is the process by which organisms are used to break down environmental pollutants, often involving the use of bacteria, microalgae and plants Fungi,however,provide an interestingroute for thedetoxificationof wastewater and soil, removing heavy metals, organic pollutants, pesticides,andmanyother toxicchemicals.

Several species of fungi, known as white rot fungi,have the ability to decay wood asthey secrete extracellular enzymes that break down lignin ? known as ligninolytic enzymes. Of course, wood is not the target pollutant needed to beremoved,but lignin,a class of organic polymers, possesses a similar structure to many organic pollutants. Laccases, a type of ligninolytic enzyme, are therefore also able to oxidise and break down a variety of other aromatic compounds in waste, such as azo dyes, bisphenol A,andseveral pharmaceuticals

The low specificity of many catabolic fungal enzymes is an attractive feature of mycoremediation,allowingmany ligninolytic enzymes to act on other substrates such as

polycyclic aromatic hydrocarbons(PAHs) ? a byproduct of fossil fuel combustion, waste incineration, and steel production PAHs are known carcinogensand havealso been linked to cardiovascular disease Whilst bacterial degradation of PAHs is also a possibility, the extracellular natureof fungal enzymesmeans that they are able to diffuse towards the pollutant moleculesin soil and thustheinitial attack on the PAH molecule ismore useful ? a feature not seen in bacteria Additionally, microbial enzymaticactivity isusually limited to low molecular weight PAHs, with higher molecular weight molecules being recalcitrant (resistant to decomposition).Yet, studieshaveshown that fungal enzymeshave the capability to overcome this As opposed to fungi,bacteriaoften use the pollutantsfor their own growth This means that the efficiency of their degradation relies on the benefits reaped by the bacteria from the products At low concentrations of pollutants, or if the molecules have a low energy content, the bacterial breakdown of the molecules is less efficient, and this presents a problem that can be solved by mycoremediation. Degradation pathways in bacteria are in general much more specific than fungal pathways, and this creates a difficulty for them to decompose large, complex molecules with high numbers of functional groups.

So, should all bacterial cleaning methods be replacedwithmycoremediation?

Not exactly In fact,studieshave shown that the presenceof themycelium in fungi allows for increased movement of bacteria in soil which has physical barriers such as air filled pores Fungi could therefore not only be used to degrade pollutants themselves, but alsotostimulatebacterial breakdown

Organic pollutants are merely one type of chemical waste, with metals, particularly heavy metals, posing a significant threat to the environment. Metals such as cadmium, lead, nickel, and mercury are often generated through the mining of metal ores and electroplating, and again are associated with organ damageand carcinogeniceffects

Although complex organic compounds have thepotential to bebroken down into smaller molecules, metals, being elements, cannot be degraded further Instead, they must be either transformed into lessharmful species, or separated from any susceptible part of the organism ? such as by intracellular immobilisation.For example,some members of the Aspergillus genus are able to reduce Cr6+ to Cr3+ , a much less toxic form. Fungi

are able to take up the heavy metals and removethemfromtheground by biosorption to their cell surfaces, where they then enter the mycelium passively Yet fungi have applications beyond the environment. A study from the VTT Technical Research Centre of Finland reported an 80%recovery of gold from electronic waste using mycoremediationmethods

Mycorrhiza is the mutual symbiotic relationship between fungi and plants, in particular between fungi and the roots This often enhances the decontamination activitiesof theplants,aidingin theuptakeof both nutrients and heavy metals Mycorrhizal fungi reduce the harmful effects of thepollutant moleculeson plants,allowing them to continue to grow, while also providing the them with water and minerals. In return, the plants supply the fungi with sugarsproducedby photosynthesis

Mycoremediation seems to be a sustainable and cheap method to clean up waste, with the fungi not only directly decontaminating the environment, but also increasing the capacity of both bacteriaand plantsto do the same,resultinginahealthier ecosystem.

Lipid Nanoparticles: A New Era of Vaccines

Thomas Hallé

The Covid 19 pandemic boosted interest in the biotechnology behind the various strategies used by scientists to halt the spread of the virus One key reason we were able to return to our daily lives was the nationwide vaccination programme, and whilst there were a variety of different vaccine platforms used by pharmaceutical companies, Pfizer and Moderna were the first companies to bring a vaccine using a

nucleic acid platform to market These rapid responses represent key progress in our ability to swiftly design and manufacture viral vaccines Although this technology has been available for over four decades, in the past it was received with scepticism by scientists who were unsure of its ability to manifest into a viable vaccine The reasons for this doube were twofold: mRNA has an incredibly delicate structure,and itsstrands

possess a negative charge, making it difficult for them to pass through the largely hydrophobic phospholipid membranes that surround cells.Scientists,however,wereable to turn to a delivery technology,with origins older than theideaof mRNA therapy itself,in order to revolutionise the concept into a working vaccine delivery mechanism ? that technology waslipidnanoparticles

The lipid nanoparticles currently used as a vehicle for the delivery of mRNA and other therapeutic agents have undergone years of development. They have been engineered to exhibit more complex internal architectures and enhance physical stability,both of which ultimately increase specificity. The earliest generation of lipid nanoparticles, liposomes, was discovered when scientists observed closed lipid bilayer vesicles forming spontaneously in water These liposomes consist of one or several bilayers, which range in size from 20 nm to 100 nm, with smaller liposomes being preferable due to their increased chanceof phagocytosis.Their structural properties meant they were immediately highlighted as potential drug delivery vehicles. This is because their hydrophilic aqueous interior, and hydrophobichydrocarbon chain region in the bilayer, can carry both hydrophobic and hydrophilic drugs On a simple level, to

Liposomes have been engineered to avoid recognition (which prevents an immune response and so premature destruction) and to have increased specificity Targeted liposomes are designed with surface attached ligands to recognize and consequently bind to specific receptors present on the surface of cells. The liposome's membrane is very fluid, and so a dynamic organisation of targeting ligands is displayed. This allows for optimal binding to cell surface receptors These targeted liposomes are generally prepared by conjugatingsmall molecule ligands,peptides, or monoclonal antibodies to their surface Furthermore, liposomes have also been heavily engineered to prevent removal from the blood flow by phagocytes To avoid

deliver the drugmoleculesto asite of action, the lipid bilayer fuses with the cell surface membraneof thetarget cell viaendocytosis.

detection, liposomes have been coated with biocompatible inert polymers, typically polyethylene glycol which attaches to the heads of lipids in the bilayer This has given rise to a class of liposome known as the ?stealth liposomes? , as they are almost ?invisible?tocellsof theimmunesystem

The latest successful use of lipid nanoparticles is in the delivery of mRNA in the context of Covid vaccines. These vaccines deliver mRNA encoding for the SARS CoV 2 spikeproteinintothecytoplasm of host cells, where it is translated in the ribosomes into the spike protein, which thereby acts as an antigen to stimulate an

immune response to the virus Each nanoparticle used in the vaccines is approximately 80 nm to 100 nm in diameter, and contains approximately one hundred mRNA moleculeseach.

macropinocytosis or receptor mediated endocytosis. Following cellular internalisation, LNP?s are trapped in endosomal compartments (essentially a lipid bubble), and consequently the endosome?s acidic interior protonates the heads of the ionizable lipids, making them positively charged. This positive charge triggers the LNP to undergo a conformational shape change, which helps it break free from the endosome and ultimately release the mRNA intothecell cytoplasm

The lipid nanoparticles (LNPs) used in both thePfizer and theModernavaccines contain an ionisable lipid. This lipid is positively charged at low pH, allowing for RNA complexation, and is neutral at physiological pH,which reducesthe potential toxic effects and facilitates payload release The LNPs also contains a PEGylated lipid to reduce opsonization by serum proteins and clearance by phagocytes (as mentioned before, to prevent the destruction of the delivery vehicle by phagocytes prior to its reaching the target cell) The phospholipid distearoylphosphatidylcholine (DSPC) and cholesterol help to pack the mRNA into the lipid nanoparticles Furthermore, the hydrocarbon chains found in the bilayer of the LNP are connected through biodegradable ester groups, allowing for their safe clearance after the mRNA reaches thecytoplasmof thetarget cell

Oncethelipid nanoparticlesreach thetarget cells, they can be internalised by

In essence, the LNPs used in the COVID 19 vaccines contain just four ingredients: ionizable lipids whose positive charges bind to the negatively charged backbone of mRNA,pegylated lipidsthat helpstabilisethe particle, and phospholipids, as well as cholesterol molecules that contribute to the particle?s structure Thousands of these four components help to house the mRNA, shieldingit from theenzymesand cellsof the immune system, and translocating it to the cytoplasm of target cells, where it can finally be unloaded and used to code for the spike protein Lipid nanoparticle technology has meant that mRNA vaccines, which reign supremein thevaccinemarket for their rapid development and manufacturing, have been able to reach the market and thereby tackle Covid 19 containment. This technology provides a promising future for subsequent responsestoviral pandemics.

Book Reviews

The Emperor of All Maladies By Siddhartha Mukherjee Yuxi Liu

From injecting patients with folic acid to the modern immunotherapy technology, Mukherjee describes in depth the medical journey of humanity?s4,000 year war against cancer In particular, he pays ultimate respect to generations of doctors and researcherswho have dedicated their entire livestofightingthiswar

The journey beginswith thestory of chemist Sidney Farber and his perseverance in finding the cure for acute lymphoblastic leukaemia. Working at a children?s hospital, he witnessed the unwavering pain and endless suffering of affected children, and the hopelessness of doctors (at the time there were no treatment options) Driven to end their agony, he worked as a public cancer research advocate and pioneered the first nationwidecancer fundraisingcampaign together with activist Mary Lasker. Unlike doctors at the time who used radical discectomy to ?slice?out the tumour, as an intelligent chemist, Farber turned to chemicals and discovered a novel cancer treatment ? now knownaschemotherapy

Mukherjee also highlights the vital role of statistical data analysis in medical research The first example being scientist Percival Pott, who noticed an unusual number of young chimney sweepers diagnosed with scrotal cancer in the 1980s, which was later discovered to be due to the accumulation of

carbon soot in their lungs. This led to the term ?carcinogen? appearing in our dictionaries for the first time In addition, as part of Farber?s research group, scientists Doll and Hill werefirst to discover thestrong link between smoking and lung cancer This wasthe inception of epidemiology (the study of populationstolearnabout disease)

In addition to chemical carcinogens, many viral carcinogens were also linked to cancer. The most notable of those being the HPV virus, the culprit in 5% of total diagnosed cancers worldwide and roughly all cases of cervical cancer in women ?Prevention is the best cure?,asMukherjeestates.

So what are the treatments available? Unfortunately as Mukherjee mentioned in ?The Gene? : out of the several million

biological molecules present in the human body, only 0 025% can be altered by our modern pharmacopoeia We are merely starting to comprehend the entirety of the human anatomy,and as such our treatments are limited The big challenge of cancer treatment hasalwaysbeen finding a suitable target site which exclusively suppresses the growth of cancer cells Nevertheless, it also meansthat if aspecificgenemutation can be identified and linked to a type of cancer, targetedtreatmentscanbedeveloped

The presence and feasibility of gene-sequencing technology may prove to be the turningpoint in thiswar The success of the drug ?Herceptin?in targeting ?Her 2? positive breast cancer patientsissure to act as a stepping stone towards our ultimate victory Regardless of prevalence, we must increase our financial motive and further our research into the mechanisms behind tumour growth if wehopeto stand achance of curingsuchlife-threateningillnesses.

A Brief History of Time By Stephen Hawking

Haruki Matsunaga

The book published in 1988 by one of the most brilliant theoretical physicists in history hadinthefirst tenyearsof itsrelease already formed a monumental landmark for science Ranging from profound discussions about the origins of the universe to detailed insights of elementary particles, Hawking shares,alongwith hisoffbeat humour,abrief history of time. In this book review, I will go into further detail into the chapter which I found the most fascinating: chapter four on TheUncertainty Principle.

Hawking begins by describing the views of French astronomer and polymath Pierre Simon Laplace regarding the universe?s purely deterministic nature In a book he wrote in 1819, Laplace asks the reader to imagine an omnipotent demon who knows everything about the universe, this being the exact positions and momentumsof all particlesin theuniverseat once Pierre Simon proposed that this demon would be able to predict anything in future by knowing everything from the past This was determinism in a nutshell If we

know the past, surely we can accurately predict thefuture

The scientist then follows through this by commenting on another monumental scientific discovery, the formulation of the Rayleigh-Jeans law at the turn of the century The law?s intended use was for calculating the energy intensity released fromblack bodies. Theformulastates:

By using this, Hawking suggests the ridiculous conclusion that it entails if we base it on determinism He explains that if we go by the law ?a hot body should radiate the same amount of energy in waves?with different frequencies (which we know is absurd), since frequency is unlimited, we couldarguethat infiniteenergyisradiated

The author then introduces us to Max Planck?s invention of quantum theory through his solution to the black body radiation issue He proposed that energy emitted from electromagnetic waves can be quantised into packetsof energy rather than being continuous This would mean that, at certainhigh frequencies,theenergy required to release a single quantum may be more than isavailable Thustherateof energy lost by black holes would be finite and not limitless.

The theorist then discusses the most significant topic in the chapter, the uncertainty principle which was created by Werner Heisenburg in 1926 Heisenberg argued that finding the accurate position and momentum of a particle is impossible. The German scientist believed that to find the future position and momentum of a particle, one must find its current values To find these measurements, one shines light, quiteliterally,onto theparticle.For themost accurate position of the particle to be found, the wavelength must be as low as possible However, by Planck?s quantum theory, we cannot use an arbitrary amount of light but a quantum Although this would be ideal, this singular quantum will affect the momentum of the particle significantly and thus our measurements of the speed of the particle would be invalid. If we tried to measure the velocity of theparticle,wewould need to use light of a higher frequency. This would lead to a less accurate result for the position of theparticle Therefore,wecannot accurately find out the position and the momentum of an object at the same time This famous dilemmaisrepresentedby thisformula:

? =Uncertainty of positionof particle p=Uncertainty of momentumof particle ? =Planck?sconstant

Quantum mechanics is then introduced. Hawking explains how Heisenberg, Erwin Schrödinger, and Paul Dirac reformulated quantum theory into what we now know today as quantum mechanics In this theory, the position and the momentum of a particle was combined into one singular ?quantum state?Quantum mechanicsdoesnot output a single result of a process but rather the likelihood of separatedifferent results.

Stephen Hawkingthen concludesthechapter by explaining how quantum mechanics may still to greatly influence the scientific world and may even disprove some of the cornerstones of physics. It is even hinted by Hawking that quantum mechanics may reinforcethe?downfall?of Einstein'stheory of general relativity.

Hawking?s ability to disseminate frighteningly difficult topics in a simple manner is what stood out to me I was also attracted to the fact that for each analysisof a theorem or a principle,he alwaysleft some bits of knowledge out I enjoyed figuring out the answers to these questions and I believe in thisbook,Hawking enticesusto do so in a very skilled manner Who would have known that aman without without the ability to talk could writesuchaneloquently shapedbook?

Chemistry

The Catalytic Condenser ? a Chameleon Device Appreciating the Value of Catalysts

Teddy Onslow

Asthe world movesaway from fossil fuelsin the modern pursuit of a green economy, we have become increasingly dependent on cleaner forms of renewable energy, such as solar and wind power Green ammonia is capable of delivering clean power to more markets by capturing, storing, and shipping hydrogen for use in emission free fuel cells and turbines. Having identified this great opportunity, chemical companies are developing a route to green ammonia in which hydrogen is produced by water electrolysis ? a method which can be poweredby alternativeenergy ? rather than from the burning of hydrocarbons. This will make ammonia production virtually carbon dioxide free However, by estimates, the production of green ammoniacostsbetween two and four times as much as conventional ammonia production, the cost of catalysts critical to its production accounting for a significant proportionof thisheavy cost

Catalysts increase the rate of a reaction by enablingalternate pathwaysfor the reaction with lower activation energies, all whilst remaining unused and unchanged. Metals such asplatinum,palladium,and rhodiumare catalysts used to manufacture important materials and chemicals in many industries. Rhodium and Platinum alone cost more than $529,000/kg and $31,000/kg respectively Their rarity drivesupmanufacturingcosts.

A team from theUniversity of Minnesotahas designed and produced a new instrument, the catalytic condenser, which is capable of fine tuning cheaper and more abundant metalsto behave like these hugely expensive metal catalysts by simply varying an applied voltage. This breakthrough in the chemical treatment of ordinary metals has the power to revolutionise the future of sustainability. These changeable metals are often referred to as chameleon metals for their ability to metamorphose their surface chemistry into specially selective structures for the best performance The catalytic condenser uses ultra thin film strips of alumina and graphene,which both cost lessthan $225/kg Therefore,thisdevice allowsthese metalsto act as catalysts way above their paygrade. Reactions where wind and solar power are taken to convert water into ammonia are Sabatier limited;theSabatier Principlestates that the interactions between the catalyst and thesubstrateshould be?just right?,that is neither too strong nor too weak If the interaction istoo weak, the molecule will fail to bind to the catalyst and no reaction will take place On the other hand, if the interaction is too strong, the product fails to dissociate. This means that when looking at the rate of reaction we can plot different catalytic materials such that we see an optimum in performance. We already have materialsthat achieve thistheoretical ?speed

limit?for chemical reactions, however, these reactions are still far too slow to be viable for technologies required to address problemssuchasclimatechange

Thedeviceiscomposed of alayer of alumina (the solid acid site) on a layer of conductive graphene,which restson top of an insulating layer of hafnium oxide, supported by a conductive silicon layer. When applying a voltage, electrons or holes (the removal of electrons) are added to the catalytic layer and perturb the performance of the material This begs the question of how much charge should be added to the plate in order to reach optimal rate of reaction? When a voltage was applied to the device and the charge uptake measured, it was experimentally found that there isalmost an order of magnitude more charge uptake with alumina and graphene together, versus only graphene, allowing us to infer that charge can be imagined to seep into the alumina About 10% of an electron, on average, is emitted per active site on the alumina. A reaction involving the dehydration of

isopropanol to propene was used to investigate how altering the voltage affects the rate of reaction In figure a (leftmost in bottom figure), the purple line shows an alumina material where positive bias (when holes are added/electrons are removed) of 3 V hasbeen applied and themetal transforms. This clearly indicates that the rate of the dehydration increaseswhen apositive biasis applied, and also that the temperature corresponding to the peak rate of propene formation decreases. Therefore, as seen in figure c, the activation energy decreases when a positive bias is applied When we further examine the surface chemistry at the active site (alumina), under positive bias, the bond length between aluminium and oxygen atoms decreases, and so they strengthen. Thus, the binding energy increases as isopropanol binds more strongly to the aluminasurface,resulting in lower activation energy for thereaction

Considering Figure b, we see the rate of propene formation for +3 V Al2O3 and neutral Al2O3 These chameleon metals? ability to switch between these two states 1,000 times per second provides us with the uniqueability to programmethemby sending different electronic signals to tune the material to desired characteristics at different stages of the reaction Consider a reaction where reactant A forms product B. A adsorbs and, under a strong positive bias, you can bind A very strongly and it will react to form Bbut then immediately put electrons

back in so B can desorb. With the ability to change the surface chemistry of a catalyst over time,weareableto lower theenergy of the transition state by applying a voltage, then flip to another state which gives very fast desorption from thecatalyst In fact,the instrument builds upon previous research from this Minnesota University team on catalytic resonance theory, which argues that by applying an external wave at the catalyst surface that resonates with the oscillations of binding energy and transition energy, a reaction can be drastically accelerated by carefully tuning the amplitude and frequency of the wave By making the frequency of changes to the applied voltage equal to the frequency of

these oscillations, we are able to reach a resonant frequency that allows for reaction rates much higher than the theoretical maximum of catalysts (the Sabatier optimum). The amplitude also has a logarithmic impact on the enhancing catalyticrate.

The prospect of cheaper and tunable catalysts could be revolutionary in both storingrenewableenergy,aswell asavariety of other projects, such as cheaply and effectively forming key components of bioplastics. This new development has a myriad of exciting possibilities in the future and will hopefully play an integral role in protectingour planet.

The Chemistry Behind Acne

Alexis Andronikos

Acne is a common skin condition which disproportionately affects those going through puberty. The main symptoms are facial ?spots?,and hot and oily skin which may be painful to touch Significant capital and time have been invested into improving treatments given it is such a vast and profitable market However, whilst treatments are available, we are yet to developacure

This skin condition is, in the most part, caused by a substance called sebum. Sebum is composed of triglycerides, wax esters, squalene,and small levelsof cholesterol It is produced by humans and its main purpose is to maintain soft skin and shiny hair;however, especially duringteenageyears,high levelsof testosterone result in excess sebum production This excess can clog up pores, allowingbacteriathat feed off dead skin cells

to thrive, and cultivating sebum producing toxins that damage the lining of the pore A blocked pore initially turns red, as blood (white blood cells) rushes to the site of infection Whiteheadsform asa result of the accumulation of dead skin cells, pus, and deadwhitebloodcells

Acne products are quite divisive, however, the most effective ones tend to contain at least one of benzoyl peroxide, salicylic acid, alpha hydroxy acids or sulfur Alpha hydroxy acidsare a classof chemical compoundsthat consist of acarboxylicacid substituted with a hydroxyl group on the adjacent carbon These are believed to battle acne by removing the top layer of dead skin cells (which bacteria feed off), reducing levels of sebum production. Sulfur is believed to be effective as similarly it removes dead skin cellsandabsorbsexcesssebum.

Benzoyl

peroxide hasastructural

formulaof (C6H5?C(=O)O?)2 Upon application, it decomposes to form benzyl radicals and benzoic acid. Benzyl radicals kill bacteria, and benzoic acid unclogs pores which also contributes to the reduction of bacterial accumulation. Benzoyl peroxide is often synthesised in three steps The first step is the Grignard synthesis of benzoic acid from bromobenzene. A Grignard reagent is a substance with a very polar carbon magnesium bond in which the carbon hasapartial negative charge and the magnesium has a partial positive charge This step is followed by the reaction of benzoic acid to form benzoyl chloride. Finally, benzoyl chloride is reacted with hydrogen peroxideto form benzoyl peroxide as a final product. Alternatively, it can be produced by reacting benzoic anhydride with an alkali metal perborate in aqueous solution

A beta hydroxy acid is an organic compound that contains a carboxylic acid functional group and a hydroxyl group separated by a carbon atom Salicylic acid is a beta hydroxy acid often found in skin care products combatingacne.It islipophilic? meaningit is able to dissolve in oils and fats ? which allows salicylic acid to penetrate skin layers and bind and destroy sebum. Furthermore, it also has anti inflammatory effects However, although research shows that salicylic acid is moreeffectivethan aplacebo,it hasnot been proven to beextremely effectiveand can also cause irritation and dry skin (as can benzoyl peroxide). Salicylic acid is a naturally occurring compound which can be isolated from the bark of the willow tree. It can also be synthetically produced, either by biosynthesisof theamino acid phenylalanine, or from phenol.It isoften produced usingthe Kolbe Schmitt process shown below Naturally,salicylicacid and itsderivativesare also found in fruits, particularly berries, and vegetables Interestingly it is also often used inthesynthesisof aspirin

Accutane (otherwise known as isotretinoin) isrenowned asthemost effectivemethod of treating acne However, the side effects are more extreme and much more common.The list of common sideeffectsincludesdry skin, eyes, nose, and lips; irritation of the skin; sore mouth or throat; headaches; and muscle pains The more serious side effects include unexplained bruising, dizziness, stomach pain, nausea, bloody diarrhoea, increased mental health problems and prolonged headaches However, accutane is deemed to be very effective nonetheless. Isotretinoin?s chemical structure is shown below This structure can produce

preparation of isotretinoin (13-cis isomer of vitamin A acid) The reaction conditions are perfect for industrial scale production, and ensure a high quality product; levels of related isomeric impurities such as tretinoin (all trans retinoic acid) and 9,13-di-cis-retinoicacidareextremely low.

stereoisomersowingtothealkenegroupson one of the side chains (with each carbon across the double bond bonded to two different groups). Its mechanism of action involves alterations in the cell cycle and apoptosis (programmed cell death) These actions reduce sebum production, preventing the blockage of pores and the growth of acne producing bacteria Shown below is an efficient process for the

In conclusion,due to endlessresearch in this field,therehasbeen significant development of acne treatments However, many are still sceptical of the effectiveness of these treatments, and many doctors believe that a healthy lifestyle and diet can be just as effective. Furthermore, many of these treatments display fairly unpleasant side effects as mentioned ? particularly with accutane,although it iscurrently deemed the best long term solution to acne Cost also presentsasignificant issue? a30 day supply costs over $200. In the future, with continued research, it is likely that more established treatments will be developed andbecomemoreaccessible.

The Biochemistry of Coffee

Seb Elliot

Coffee consists of 2 3% of caffeine and is responsible for most of coffee's known characteristics.

It hasachemical formulaof C8H10N4O2 and it is a methylxanthine, with its IUPAC name being1,3,7 - trimethylxanthine. The caffeine molecule, shown adjacent, is

made of heterocyclic rings, which are cyclic compounds that have atoms of at least two different elementsasmembersof itsring.

Caffeine is able to bind to adenosine receptors(atypeof ribonucleotidesimilar to that of adenine and guanine) owing to the similarity in shape between caffeine and the adenine component of adenosine. Its structural similarity with adenosine, shown below, allows caffeine to act as a competitiveinhibitor

fatigue, but also has anti-inflammatory effects The anti inflammatory effects of caffeine are due to the nonselective competitive inhibition of phosphodiesterases (PDEs). Inhibition of PDEs raises the intracellular concentration of cyclic AMP (cAMP), activates protein kinase A, and inhibits leukotriene synthesis, which leads to reduced inflammation and innateimmunity.

To extract thecaffeinemoleculefrom coffee and tea plants, decaffeination needs to occur. This is when a carbon dioxide solvent ispumped into sealed vesselswith thecoffee beans, the caffeine dissolves into this solvent,andisinturnextracted.

The caffeine molecule is found naturally in the seeds of coffee plants and the leaves of tea plants Within these plants, the caffeine molecule increases the rate of many biological processes, including photosynthesis, and water and nutrients absorption.

Upon consumption, caffeine binds to adenosine receptors in the central nervous system (CNS), which inhibits adenosine binding Adenosine has multiple functions, most notably sleep promotion and maintenance. The underlying mechanism is centred upon the release of GABA (an inhibitory neurotransmitter), which inhibits neuronsinvolvedinwakefulness

Consumption of caffeine also causes an increase in the oxygen supply by coronary vasodilation, and decreases the consumption of oxygen by lowering the heart rate. This inhibition by caffeine therefore results in its known effects of increasing heart rate and ?concentration? throughthelack of promotionof sleep.

Caffeine is not only known to decrease

Computer Science

The I llusion of the Third Dimension and the Tropes of Modern First Person Shooters George Niedringhaus

Doom (1993) was released in 1993 by id Software for MS DOS, and came to home consolesover the next few years With a file size of only 2.39MB, it was difficult to fit a 3D game into that little space In contrast, DoomEternal, the latest instalment,takes up nearly 38 thousand times as much space, at an obscene 89GB The original game used a technique called ?ray casting?, colloquially known as?2 5D graphics?? even though the levels themselves exist as 3D objects, the demons, projectiles, weapons and pickups were all two dimensional sprites The enemies in particular had eight versions of every stage of their animations,one for each major angle they could be seen from This technique is used in some more modern games, such as the mainline Danganronpa games In their case, however, that was an artistic choice rather than a compromise to ensurethat thegamecouldrunproperly.

The engine used in Doom, called ?id Tech 1?, is quite simple as would be expected for the time It considers things only two dimensionally at first,withaheight used during rendering. It has vertices (internally referred to as ?vertexes?), which are joined to form lines(?linedefs?),which can haveone or two ?sidedefs? . Sidedefs are grouped together to form polygons (?sectors?), which represent subsections of the overall level Sectors have a floor height, ceiling height, light level, and floor and ceiling textures

Sidedefs have three textures, middle, upper, and lower One sided linedefs (solid walls) use only the middle texture, but two sided linedefs (which are entrances between sectors) use the upper and middle to fill the gaps between sectors with different floor/ceiling heights (eg stairs) A two sided linedef could also beused to makesomething appear tofloat.

Doom utilises a system called binary space partitioning (BSP) The data for each level is generatedbeforehand.Thelevel issplit into a binary tree, with the root node representing the entire level,and each subsequent node is a specific area.Each branch of the tree splits the area into two smaller areas The line segmentsfrom split linedefsarecalled ?segs? . The lowest nodes are always convex polygons,that do not need to besplit further, called subsectors ?SSECTORS?, with a list of associated segs Thelevelsarethen rendered recursively, starting at the root node, and each time selecting the subnode closest to the camera, drawing subsectors when the algorithmreachesthem

All of the walls in the game are rendered vertically, which is why vertical camera movement istypically not possible A stopgap solution called ?y shearing? does exist, but causes a great deal of distortion at severe angles. The floors and ceilings (flats), however, are significantly less elegant They

aredrawn usingan algorithmsimilar to flood fill, so if the BSP data is built poorly, there can be ?holes?in which a flat bleedsinto the edges of a screen Flats are rendered as ?visplanes?,horizontal runswithaset height, light level and texture. Each x position within the visplane has a set vertical line of texture.Thislimit can causetheneed to split visplanes, such as where there are overlapping objects on a flat This was an important limitation, as Doom had a limit of 127 visplanes,whichcould bereachedwitha 12x12 chessboard pattern Visplanes are rendered alongside segs, extending towards the applicable vertical edge As a result, the order in which renderingoccursisimportant so that closer visplanes cannot be ?cut off? by other visplanesmeant tobebehind them

Finally, things, or sprites Each sector has a linked list of spritesstored within. Theseare then drawn if they are within the player?s field of view.Theedgesof spritesareclipped if they are behind previously rendered walls, which is aided by the fact that sprites are

stored in the same column based format as thewalls,but thereisnot thesameguarantee that sprites will be rendered in the correct order The sprites for enemies are selected based on what action the enemy is performing (attacking, moving, etc.), as well aswhat direction they areviewed from Each individual enemy has eight versions of every stage of every animation. Doom and Doom II both used the same engine, but Doom 64, released on the Nintendo 64 used an improved version. 64 had 3D maps, and to a very limited extent, platforming The ?platforming?was mostly using the sprint to make it across small gaps, but it was an important improvement that the first two gamescouldnot havehandled

To conclude, while the was an interesting game engine, it didn? t have much longevity Similarly to comic sans, it worked well given the restrictions of the time, but it can? t take advantage of modern computing power as well as3D graphicscan.

How does a Bayesian Neural Network Model Differ from a Traditional Point-Estimate Neural Network?

Victor Shao and Roman Lipko

A neural network is a computer system designed to mimic the workings of the human brain. It consists of the input layer, the hidden layer, and the output layer, all of which contain interconnected processing nodes, or neurons, that can learn to recognize patterns of input data Each node can be thought of as a function represented by aset of weightsand activation inputsthat can either amplify or reduce the specific

input to be passed on to the next layer The weights and activations form the input function, which is usually altered by a node specific bias value This is then transformed by an activation function, for example, a sigmoid function which produces an output between 0 and 1,and isthuseasier tobepassedthrough.

The way the neural network learns is by adjusting the weights and biases of each individual node so the final output matches the desired result This is done by representing the desired output as ?Vector A? , grouping the actual layer?s result as ?Vector B? , then finding the cost function which is represented by the difference between ?Vector A?and ?Vector B?This cost function is usually computed cycle by cycle until it reaches convergence, which means the error between the predicted output and the actual output is close to 0 (although it could run an infinite number of times to traindata)

Differences between a Bayesian Neural Network (BNN) and a Point Estimate Neural Network (PENN)

The main difference between a PENN and BNN is how each node is represented; in a PENN,thenodeisdescribed asasinglevalue, whereas in a BNN it is expressed as a probabilisticdistribution.

A BNN is used to estimate the underlying probability distribution of a given input. For example, with reference to the below figure, instead of a single value, the weightsof each nodearecomputedby anormal Distribution.

BNN (t op), PENN (bot t om )

Furthermore, different BNNs work in different ways Some may have the final output as a probability distribution, whilst some may only do so for the node functions (eg weightsand biases) Thisisin contrast to traditional point-estimate neural networks whichsimply output themost likely estimate

Below are some of the main advantages of BNNs. Firstly, they are more robust to overfitting ? the problem of being excessively trained sothat it only respondsto a narrow range of inputs ? by addressing regularisation properties (innate nature via probability distributions). In addition, since BNNs account for uncertainty in the data, they are useful in making predictions However, a Bayesian approach is more computationally expensive since each time the network makes a prediction, it must update its beliefs about the model parameters given the new data This means it?s hard to scale to larger problems and is relegated to more specific questions such as inmolecular biology andmedical diagnosis

The Travelling Salesman Problem

Victor Shao and Roman Lipko

For years, computer scientists have created optimization algorithms for perplexing and versatile problems, of which the Travelling Salesman Problem (TSP) has been a benchmark for many optimizationmethods. The problem goes as follows: ?Given a list of citiesand the distancesbetween each pair of cities,what istheshortest possibleroutethat visits each city exactly once and returns to theorigincity?"

essentially techniques or algorithms used to produce solutionswhich may not be optimal, but areefficient in thegiven time A heuristic function creates a cost (a value generated from the function) to evaluate the accuracy of the current solution Its purpose is to decrease this cost, to increase the accuracy of thesolutiontotheoptimal one.

The image above gives an example of a solution to a problem. Here, the dots represent the cities and the line connecting themistheoptimal solution.

It is considered to be a ?non deterministic polynomial (NP) time hard? problem ? in simple terms, it is both hard to solve and verify, and more technically it can be transformed into another NP problem To give a more intuitive understanding, the maximumnumber of pathspossiblein anaive solution (a brute force approach of trying all combinations) for 5 citiesis12 paths.For 10, it is181,440 and for 20 cities, it increases to 6.082 ×1016!

However, due to intensive studying since 1930, there are a range of approximate and exact algorithms to solve this problem exactly to 10s of 1,000s of cities and approximate to millions The majority of these algorithms use heuristics, which are

Exact algorithms often take a very long time to execute There are relatively fast techniques to compute an exact algorithm, such as the Held Karp algorithm, which is an application of dynamic programming. It defines a set Sfor the cities which the route has to go through before reaching its destination, d. It starts with |S|=0 and gradually increases |S|, computing the smallest distance for each combination of size |S|. The smallest distance through S is broken up into the minimum value between going from some city 'c' in S to the new destination while going through the rest of thecitiesin S However,thesmallest distance to 'c' while goingthrough the other citieshas already been computed before in the set of |S| 1, so it is easier to compute the new possible distances Although this is faster than a naive approach,it still hasto take into account a considerable number of possibilities, thus resulting in a time complexity of O(n22n).

As shown, exact algorithms get very computationally expensive as the number of citiesincreases,which waswhy approximate algorithmsweredevised

One simple yet inefficient heuristic algorithm is the nearest neighbour algorithm, which is a type of greedy algorithm In this algorithm, the salesman always chooses the nearest unvisited city as his next move. It constructs a tour very quickly but relies heavily on the positions of the cities and may sometimes produce the worst case. Thus, techniques, such as the pairwise exchange, exist This removes n edges (where n is a pre specified integer) and replaces these with n different edges that reconnect thefragmentsinto anew and shorter tour

The third and final algorithm explained here istheAnt Colony Optimization,which usesa simulation of theAnt Colony System (ACS),a type of swarm intelligence method. It imitates real ants which lay down pheromones directing each other to resources This algorithm sends out a large number of so called ?ant agents?to explore many possible routes on the map. They travel through the graph based on heuristics from the starting point and ?pheromones? These pheromones are values added to the edgesof thegraph,increased by antsmoving on the edge, to increase the likelihood of an ant travelling through that route. Once it reachesthe end of the tour,it depositsmore pheromones around the completed tour it has taken. From this, the later simulation iterationsof antswill locate better solutions on averageand at theend,theroutewith the most deposited pheromoneswould beavery close approximation to the shortest path

These algorithms are very basic examples of some sub-optimal ways to compute an approximate solution and there are many more, such as the Christofides algorithm, which wasomitted from thisarticle owing to the necessity of explaining graph theory extensively

Asexplained earlier,thisproblem appearsas a sub problem in many areas, from order picking in warehouses to drawing pictures. A famous example of a picture generated by theTSPisoneby Robert Bosch, created in February 2009, of the Mona Lisa using aTSPproblem of 100,000 cities It was optimised by Yuichi Nagatain March 2009 to 5,757,074 boundsand thereisa$1,000 prize to anyone who beats this record, hosted by the ?TSP Art website and the University of Waterloo? . So if anyone is interested, have a crack at thisproblem!

An illustration of Ant Colony Optimisation

Engineering

?EJECT! EJECT!?

Suleyman Ansari

Inspired by the recent release of Top Gun: Maverick, I was fascinated by the way ejection seats work, their remarkable success record (they have saved over 7,000 lives), their reliability, and their design. So how doesthisamazingsystemwork?

Since the inception of functioning aircrafts, some sort of escape mechanism has been present Duringtheearly daysof flight,when aircraft didn? t have canopies, the pilot could just bail out on their own by jumping from the aircraft with a parachute However, this was not preferred by theRoyal FlyingCorps (the predecessor to the RAF) since it could incentivise cowardice during a combat situation in the First World War.Asaircrafts became faster and more powerful, this original method of egress was no longer possible owing to g-forces and airflow situations This became especially relevant when fighter jets started to travel at supersonic speeds. As a result, new escape methods needed to be designed This led to the current basis of the ejection seat as we know it, which was initially developed by Anastase Dragomir in the 1920s However, understandably, it was only during the Second World War that innovation really took off Today, world leaders in the field such asSAAB and Martin-Baker continue to work at the cutting edge of technology to makeejectionevensafer andmoreeffective

The modern-day ejection seat is an extremely complicated system, yet the

fundamental processes are still in many ways similar to those initially introduced by Dragomir When the pilot pulls the ejection lever,thecanopy of thejet isjettisoned away from the aircraft by rocket thrusters before the pilot follows shortly after This entire process takes less than a second! However, given thewideoperatingwindow of afighter aircraft, speed and altitude can vary massively.Asaresult,apitot tubeconfigures the ejection based on the altitude and speed of the aircraft to ensure maximum safety For example, at an altitude of 50,000 feet (far above where a human can breathe), emphasisisplaced on gettingthe pilot down to abreathablealtitudeasfast aspossibleso the parachute remains shut until this position. However, at lower altitudes, the parachute must open immediately in order toquickly slow thepilot downfor alanding

Given that ejection seats are often the difference between life and death, it is important to consider the elements that make them so reliable. Since the 1940s, the success rate of ejection has increased from around 50% to over 90%, clearly demonstrating increased reliability. A single bolt can cost upwardsof $100 dueto itshigh specification; it must be manufactured with utmost precision and from the best quality materials,aswell asbeingextensively tested before use. Similarly, redundancy is incorporated into the design to ensure that theseat worksreliably evenif onepart fails

However, state of the art escape systems aren? t exclusive to fighter jets Commercial aircrafts feature similar systems. Evacuation slides utilise compressed air to inflate them quickly Safety isof paramount importancein aviation and companies are constantly

The Future of the Factory

Victor Liu

Factorieshaveakey roleinhuman society ? we may not always be aware of it, but the vast majority of our productsstartedlifeina factory of some sort In 1771 Richard Arkwright opened Cromford Mill, a cotton mill regarded as the origin for modern factories. It housed yarn making machines that were powered by water wheels, and was initially home to 200 workers Its efficiency was far superior to existing cottageindustries

Since then, the industrial technology within factories has advanced rapidly. Many common elements of today?s factories are likely to persist, but new technologies are also changing the ways of mass production. The days of production lines bustling with workers are drawing to a close; automation is becoming increasingly pervasive as older technologiesarephasedout

Nowadays, most control systems in factories are based on Programmable Logic Controllers, or PLCs At their core, they are microcontrollers that have input/output pinsconnected to terminalsthat can control various light loads such as contactors or lamps. However, they differ from a consumer grade microcontroller module in their design,asthey must be robust enough to withstand the electrical noise, vibration, and other abuse of a factory environment Although these controllers have proven

aiming to improve this situation. Recently, firms have placed greater focus on helping pilots survive the violent g-forces during ejection with new developments focused on improving neck projection

reliable, one of their major weaknesses is an inability to adapt to unexpected conditions, as they are simply following a fixed program

In the future, control systems will have increasing amounts of integration with servers in the ?cloud?: communication with headquarters will bring extra intelligence to the production process. This brings new problems of cybersecurity; current best practice is to connect controllers to the factory?s internal network only Any industrial systems exposed to the internet are at risk of attack. Careful security conscious engineering will need to be applied to minimise these risks to expensive production hardware, and control will likely remain on site to minimise disruptionincaseof internet outages

The most common control loop used in such logic controllers today is the Proportional-Integral-Derivative algorithm, or PID for short In simple terms, the PID controller bases its correctional action on three things: how far the current value is from the setpoint (the error), the cumulative error that has persisted (calculated by integratingthe error),and how fast the error is changing (the derivative of the error) The proportional term makes the change proportional to the error, the integral term makes the change more extreme the longer the error persists, and the derivative term

prevents overshooting of the target value

Each term is weighted so that the controller canbe?tuned?toachievethemost control

As general computing technology advances, we can expect to see increases in the processing power of these logic controllers too Although a PID controller or sensor monitor doesn? t require much processing power, recent technologies may need more A control system of the future will likely be able to visually survey the factory and react to potential snags in real time, instead of relying on an external server to do the processing. This practice of processing data near itssourceiscallededgecomputing

Machine learning and AI based on edge computinghavemany newfound applications in the industrial space For example, computer vision algorithms can detect stray objects on a conveyor belt (anomaly detection), or let a robotic arm pick up objects in varying positions.Many tasksthat are currently performed by humans such as quality control will probably be replaced by digital eyes that can work faster and for morehours Withmachinelearning,acontrol system could automatically tune its parameters to fit a certain process; this would remove the main disadvantage of setting up existing algorithms,which isoften amatter of trial anderror.

A risk of introducing ever larger numbers of increasingly complex sensors is reliability. In a factory?s high productivity environment, reliability is key; a single day of downtime can disrupt entire supply chains, especially with the prevalence of today?s just in time supply chains This is a reason for the delay between a technology?s availability and its integration into factories Any extra processing power will likely be installed as a coprocessor, an augmentation of proven

hardware, so that the system can still operate (albeit at a reduced capacity) if any sensor develops a fault Redundancy (the incorporation of backup systems) can be used to alleviatethisissue,but increasingthe number of devices adds possible points of failure ? counterintuitively,thiscan actually decreasethereliability of thesystem!

Potentially revolutionary ideas and technologies are not limited to automation ?Batch Size One? is a completely different manufacturing paradigm, whereby products are tailor made to each customer's specifications. This is possible due to better algorithms that can generate designs based on templates, and contrives the traditional approach of mass production to leverage economies of scale When fully optimised, a batch size one factory can achieve similar profit marginstoatraditional one

Thetechnology in factoriestendsto advance stepby step,aseachnew concept istried and tested Current ideas are showing the potential torevolutionisehow factorieswork once again. One day, in the not-so-distant future, we may find ourselves using things never beforetouchedby humanhands.

Environmental Science

Constructing a 'Simple' Climate Model

Frederick Dehmel

In this article we will construct a simple model to calculate the temperature of the Earthinequilibrium.

In order to better understand this model, consider thefollowingthree lawsof physics

Firstly, power is an expression for the amount of energy transmitted in a given amount of time

The second law of physics that will often be referenced relates to intensity, which refers totheamount of power per unit area

Finally, the power an object emits is proportional to the temperature of that object to the fourth power,timesthe area of that object, multiplied by a constant epsilon (which denotes the emissivity of an object), multiplied by a constant sigma (known as theStefanBoltzmannconstant)

Using the aforementioned Stefan Boltzman equation,wecan calculatethepower theSun emits

Sincethesurfaceareaof asphereis4?r2 ,and as we know the radius and surface temperature of the sun, we can create the followingequation:

which after plugging in the values for the Sun?s radius (696,340 km) and surface temperature (5,778 K) gives us a final value for thepower emittedby theSunof:

In turn, we can use this to find the intensity of the Sun, as Intensity = Power/ surface areaof theSun:

It is worth noting that the third rule only applies for black bodies (objects that absorb all wavelengths of light) For this article, we will assume that the Earth is a black body, meaningitsemissivity isequal to1

By considering the relationship between the Sun and the Earth, as well as the physical attributesof both these bodies,wecan begin to construct a model The Sun is 150 million km away from the Earth,and emitsenergy in the form of heat and radiation, which travelling at the speed of light reaches the Earth8 minutesand20 secondslater.

Giving us an intensity of 1360 , which will be referred to as the solar constant, S. Now that the Sun?s power and intensity has been calculated,we have to analyse how the Sun?s energy interacts with the Earth. When solar radiation hitsthe Earth,it iseffectively a flat line, and if we were able to view it in 3 dimensions, we would see a flat disc crash into the Earth and wrap around the globe Thiswould mean that power from the Sun is conserved In this context, this means that power in is equal to power absorbed, denoted asPin= Pabs Pin can be written asthe solar constant timesthe areaof thedisc,and we can write Pabsorbed as the surface area of the Earth times some unknown intensity that isreceived by the Earth,which we were trying to find We can also substitute ?r2 for

the area of the disc, and 4?r2 for the surface areaof thesphere:

provedthat Iequal Sover 4,wecanmakeone final substitution:

By doingso wecan clean up theequation,as both radii refer to the radius of the Earth, allowing us to set the solar constant as 4 times the solar intensity received by the Earth:

Rearranging this leaves the intensity receivedequal to340 :

Yet not all intensity received is absorbed; a proportion of it is reflected back into space due to the phenomenon of the albedo effect This is where we introduce the albedo constant, alpha, which is just a measure of the reflectivity of an object The Earth's albedo constant is around 0 3, meaning 30% of the energy, and hence power and intensity,that theEarthreceivesisreflected

Thusthe intensity the Earth truly feelsis0 7 times the intensity received, or about 238 wattsper m2:

With a little algebra, we are given an equationthat canfindglobal temperature:

To test if our model works, we can try plugging in the valuesfor the albedo and the solar constant, giving us a value of 255 K, or 18 °C:

Now that wehavehave found avaluefor the intensity that the Earth hasreceived,we will apply the Stefan Boltzmann equation once more

Sincepower equalsintensity timessomeunit area, we can construct the following equation:

Since both areas represent the surface area of the Earth, we can simplify our equation down to I absorbed = Stefan Boltzmann constant, times by the emissivity, times by the surface temperature to the fourth power:

To help us, we can rewrite I absorbed as I received multiplied by the proportion of energy that is absorbed, and as earlier we

One crucial element that we have failed to account for isthegreenhouseeffect.

To understand how the greenhouse effect alters our calculations, we first have to understand what emissivity is; emissivity isa measure of how effective an object is at emitting energy in the form of thermal radiation. While the Earth may (almost) be a black body, and hence should have an emissivity of 1, the atmosphere is not The Earth may emit 100% of the energy it absorbsback out into space,but it first hasto pass through the atmosphere It is worth noting that greenhouse gases have an effect only on thermal radiation leaving the Earth

In a nutshell, this is because thermal radiation enters the atmosphere as shortwave radiation and leaves as longwave radiation, and greenhouse gases are significantly more effective at trapping and remitting the latter This attribute results in the atmosphere having an emissivity of around 0.612. If we retool our model in respect tothisrevelation,weareleft with:

Mathematics Catalan Numbers

Sasha Gorin Delmas

Imagine you invite 11 people to your birthday party and you all sit around a circular table. You want to greet your 11 friends with a handshake and they want to greet each other, however you do not want to crossarmswith anyone and cause a mess In how many ways can you do this?In other words, in how many ways can 12 people, sitting around a circular table, shake hands without crossingover eachother

One way of attacking this problem is by considering a specific person: person1 To ensure no one crosses over each other, and that when person1 shakes hands with someone, those in between them can all shake hands, there must be an even number of people between them Person1 can also shake hands with those directly adjacent to them. Thus, if we number each person in ascending order clockwise from person1, they can shake handsonly with persons2, 4, 6, 8, 10 or 12. We can imagine person1?s handshake as splitting up the table into 2 further groups This means that for each of person1?s possible handshakes, the question breaksdown into thesamequestion but for a smaller number of people Let?s try to visualisethis:

In the diagram above, person1 is at the bottom of the circle, a line represents a handshake and an a denotes the number of non crossing handshake possibilities for n people around the circle. Each of the different people that person1 can shake hands with is drawn above Notice how the questionrepeatsitself:

a12 =a10 +a2a8 +a4a6 +a6a4 +a8a2 +a1

Therefore, to answer this question we must look at how many wayspeople10,8,6,4,and 2 can shake handswithout crossingover.We can do this by repeating the same process. We can figure out a4 pretty easily by just

consideringfour peopleandsothereareonly 2 ways: person1 can shake hands with the person on hisleft or right Thereforea4=2 As aresult: Thus,there are 132 waysthat 12 people can shakehandswithout crossingarms.

But there is something hidden behind this problem:thenumbersa2,a4,a6 ...areactually part of a sequence called the Catalan numbers The Catalan numbers are a sequence which frequently surfaces in counting problems How many ways are there of drawing triangles in a regular n sided polygon shape?How many ways are there of getting to the point (n,n) by starting at the origin and only being able to move north or east without crossing the line y=x? How many ways are there of creating a ?mountain range? with n up-strokes and n down strokes whilst always staying above the horizontal line?And,how many waysare there for n people (where n iseven) to shake hands without their arms crossing? It turns out theanswer to all thesequestionsarejust theCatalannumbers.

A Combinatorial Proof of Wilson?s Theorem

Gabriel Trennerman

Have you ever tried to draw asmany shapes as possible, from a given point, without taking your pen off the paper?Well, it turns out that this idea can be used to prove Wilson?s Theorem (which is quite complex!) without any prior knowledge of modular arithmetic or number theory. It provides a purely combinatorial proof to a number theoretic problem which I find fascinating I hopeto giveyou agood graspof theproof by theendof thearticle

First of all,what isWilson?sTheorem? Formally, Wilson?s Theorem states that for an odd prime p, (p ? 1)! ? ? 1(mod p)

This effectively says that (p 1)! + 1 is divisible by p.Therefore, if we we show that isaninteger ,wewill bedone

Let usreconsider thequestion I posed at the start,but thistimelet usmorestrictly define some parameters.Formally,we will consider p (an odd prime) points evenly spaced around a circle ? and count the number of polygons we can form by joining these p points in a single pen stroke Such a polygon is known as a stellated p gon Note that you must also return to your startingpoint at the end

Firstly,it will be helpful to try a smaller case witha5 gonandcount how many exist

Notice that in the first two cases (red), the shape has rotational symmetry (the shape looks the same no matter how it is rotated) order five,so there isonly one of eachtype Inthe other twocases(green),the shape has rotational symmetry order one so there are fiveofeachtype

In fact, in general there are p gons you can form for a given set of p points We can quickly verify thisaswefound twelve5-gons whichisjust

Why is this the case? Let us consider the 5 gon again If you list the points that you reach in order (you must return back to the starting point, but we can ignore it) you will have six points in total, such as in the example below.These first five pointscan be in any order so there are 5! ways to arrange them However, notice that for a particular sequence starting at any of the 5 points, the same shape is produced For example, P1.P3.P2.P4.P5.(P1) and P4.P5.P1.P3.P2.(P4). Also,noticethat even if you start at thesame point, two sequences will produce identical shapes ? one which goes anticlockwise (P1 P5 P4 P2 P3 (P1)) and one which goes clockwise (P1 P3 P2 P4 P5 (P1)) If we extend this logic to a general p-gon then it is intuitively true that the number of p gons you can draw in general is just p! divided by twoandp.

Recognisethat therearetwotypesof p gons: ?regular? and ?irregular? . A regular p-gon is onethat hasrotational symmetry of order p likethat in? and ? Anirregular p gonisone that has rotational symmetry order 1 like that in ? and ? Notice that because p is prime, we cannot have rotational symmetry of any order other than 1 or p. One might then ask how many of thep gonsareregular? It turns out that this is the last step we need tofinishour problem!

If you look closely at theregular 5 gons,then you might notice that each line ?jumps?the

same number of vertices each time In ? , each line connects two adjacent vertices (a clockwise jump of one) whereas in ? each line ?jumps two?(eg connecting P1 to P3) You might then ask why there are not more than two regular 5 gons?Why are there no cases of jumps of three and four? This is because a jump of three is equivalent to an anticlockwise jump of two and similarly a four is equivalent to an anticlockwise jump of one (asboth take P1 to P2): they produce identical shapes Extending this idea to the general p number of points case, then you will notice that we have jumps of the size from 1 to Aseach sizeof jump givesa unique p gon, we thus have regular p gons!

2 (Balkan MO 2016) Find all monic polynomialsf with integer coefficients satisfying the following condition: There exists a positive integer N such that for every prime p >nN, p divides 2(f(p))! +1

This means that all the remaining polygons must be irregular! This can be simplified to But because irregular polygonshaverotational symmetry order one,then thismeansthat each type of irregular p gon must contribute p separate p gons. As there are a whole number of types of irregular p gons, then it must mean that divided by p is a whole number.Therefore, isdivisibleby p which is what we wanted and so we are done WehaveprovedWilson?sTheorem! Wilson?s Theorem is often used in some Olympiad style problems Here are some that youmight findinteresting:

1. (ARML 2002) Let be an integer such that Find the remainder when a isdivided

Medicine

The Future of Artificial I ntelligence in Medicine

Zak Farazi

The hybridization of our lives with Artificial Intelligence (AI) seems inescapable Whilst some fear this is owing to the negative depictions in media and a general lack of understanding, others see opportunity In fact,AI isalready making itspresence felt in themedical industry.

Firstly,what isArtificial Intelligence?

Artificial Intelligence is a superordinate term for computers that are able to carry out so called 'human' tasks which normally employ theuseof reasoning,perception,and self learning So how is AI currently being used in medicine? The ability to find and identify minute details accurately, efficiently,and quickly isinvaluable to those in radiology For example, a deep learning model (a type of artificial intelligence that usesmodelsinspired by the brain?sneurons) was created to aid the identification of lesions in breasts. The model was tested on data from eight hospitals: 90 7%of the MRI scans with lesions were considered to be abnormal by the AI and 40% of the scans without lesions were dismissed This shows that AI can be used to significantly reduce theworkload of doctors,givingthem time to focus on other areas This also has potential to improve productivity and reduce the likelihood of errors due to fatigue AI could be revolutionary, to such an extent that a radiologist?s job at the American College of Radiology had two main criteria: the applicant ?must be an enthusiastic,

well-trained radiologist, and excited about a future where radiologists are supported by world classAI andmachinelearning?

In recent headlines, a genetically modified pig?sheart wastransplanted into ahuman for the first time How was this done? The company that made the heart, Revivicor, did so by knocking out specific ?pig?genes which result in the heart being assailed by the immune system, and replacing them with human ones These genes promote the accommodation of themodified pig?sheart in the human body This was done using the CRISPR genome editor, which uses special RNAs (crRNAs) to find a specific matching sequence of DNA The discovery that the pig heart can be made compatible with a human is the first step in alleviating massive organ shortages, potentially saving countless lives But what if we could create individually tailored tissuesor organsfrom scratch?This is a growing field known as regenerative medicine.Stemcellscan differentiatetoform almost any specialised cell ? so they would be able to differentiate into cardiac muscle cells which could form functioning heart tissue. On the other hand, ethical issues must be taken into account Most notable of these is ?componentation? , which could potentially lead to scientists' decidingto alter thehuman body This goes against traditional human valuesandispotentiallyunethical.

Now, the question is, how does AI come into this?Deep learningalgorithmscan beused to

predict the behaviour of a cell in different conditions. By extension, it can be used to quickly and accurately predict what the cell will do in human environments ? critical information for researchers. According to Masayo Takahashi at the RIKEN Centre for Developmental Biology, through deep learning AI robots will have the ability to emulate skilled researchers in the regenerativemedicineindustry

However, AI is not without limitations. Firstly, the process of training an artificial intelligence model requires data to be collected and inputted to the program by a human being The risk is there could be bias in thesemodels,asdatacollected may not be random In addition to this, data must be pre processed before it can be used to train the AI. Hence, just as there is a regulatory body that approves which drugs and foods are released to the public, regulatory oversight which specifically assessesthe use of AI in the medical sector is absolutely imperative Thiswould help ensure that AI is not susceptible to the same biasesashuman

beings and there are boundaries around what it canbeusedfor.

Another shortcoming of AI is its general usability Most AI models are built using complex mathematical modelsand code.The average medic will not be able to easily understand or implement these models unless they undergo training, which may have cost implications especially for state run enterprisessuch astheNHS On account of this,thegeneral accessibility to AI training should be made easier and more cost-effective.

In conclusion, AI looks to be an incredibly useful resource that will, in years to come, likely play a significant role in healthcare. This has already been demonstrated by Moderna, who used AI algorithms to streamline the production process of the COVID 19 vaccine,which partly contributed to its rapid production Though an effective regulatory framework would be needed to overcomethechallengesthat exist

A Life for a Life: Xenotransplantation

Oliver Milroy-Goulding

Since the time of the ancient Greeks, humans have dreamt of replacing human body parts with those of animals Whilst science fiction writers have imagined cyborgs and metal hearts, scientists have chosen a less climactic method to tackle the more than 100,000 Britons on the transplant waiting list: pigs seventeen peopledieevery day in theUK whilewaiting for an organ, and xenotransplantation providesaprompt andplentiful supply Xenotransplantation literally means?foreign?

transplantation and is by no means a new concept Since 2000, gene editing has become a tangible reality, with breakthroughssuch asCRISPRleadingto the multi gene editing, immunosuppressing, groundbreaking transplants of today Recent examples include a pig heart put in David Bennett Sr, and a heart put in a non human primate (NHP) . ?Life imitates art,?as Oscar Wilde said, and, in this case, there are startling similarities between it and Malorie Blackman?s1997 book Pig-HeartBoy.

In the last 20 years,much research hasbeen done into preventing the rejection of xenotransplants in NHPs Recently that research hasmoved into humanstoo.Just in 2021 we saw a braindead patient receive a pig kidney, and the aforementioned pig heart transplant. 2003 saw the first big leap when the Gal antigen (an identifying marker to our immune system) was knocked out of pig genomes.However,thiswasnot without its tribulations; it took three years from cell work to birth 2012 wasaturningpoint,with the discovery of both CRISPR, and the publishing of the full pig genome, meaning it took only 150 days to create a multi gene edited piglet. This has allowed scientists to prevent both humoral rejection (the attack of tissue by antibodies and the complement system) and coagulation dysregulation (abnormal clotting in organs) through gene-editing alone. Further combined with an immunosuppressiveregimen of drugsand anti inflammatory therapy, pig hearts have lasted over 900 days in NHPs, and corneas almost 400 Experiments have shown everything from the possibility of a cure for type one diabetes, to the xenotransplantation of pancreatic islets (clumps of insulin producing beta cells), to the reversal of effects of Parkinson?s diseaseby neuronal transplantation

Despite the many benefits of xenotransplantation, just because the donor is an animal does not mean life for a life transactions should be dismissed lightly. Utilitarianism is often not compatible with major religionsandthegeneral population

Zoonotic diseases must also be considered, and whether the general populace is prepared to take such a risk for the betterment of transplantation technology and the lives that it saves Pig retroviruses

have shown no inclination of transmitting to NHPsin any studies,and can be edited using CRISPR Porcineviruseshavenot been found to spread to immunocompetent humans, with the pigs being raised in a sterile environment to ensure safety David Bennet Sr died because his pig heart was infected with a porcine virus, although there was no zoonotic transmission The virus was limited to just the transplanted heart but went haywire because of a compromised human immune system and the absence of a pig immune system. This caused mass inflammation from day 40, and the patient died about 20 days later from catastrophic organfailure.

The potentials of xenotransplantation are enormous, but the ramifications are equally as serious. Public opinion needs to be considered, and researchers must bear in mind the wide variety of ethical concerns people have instead of just blindly improving thesciencefor ?thegreater good?

Human vs Disease Mustafa Sadeeq

The ongoing battle between organisms and pathogenshasbeen eventful to say theleast. History is dotted with horror stories of plagues and pandemics spreading through nations However,duetoscientificadvances, the human population has rapidly increased over the last few centuries, with minimal impact from natural population controlling diseases But is it possible for disease to be eradicatedasawhole?

On theonehand,vaccineshavebeen proven to be highly effective in providing artificial immunity. One key example of success was the eradication of smallpox It is one of only two known diseases that have been confirmed by the WHO to have been eradicated , with the last known case in 1977. The high mortality rate (30%) drove many to search for potential cures The first form of smallpox vaccination was practised in 10th century China: smallpox scabs were blown up healthy people?s noses, who then developed a mild case of the illness and thereforedeveloped immunity.Thesmallpox outbreak of the16th century meant that the disease was the main cause of mortality in Europe during that period. As modern medicine progressed, an initial vaccine was proposed by Edward Jenner in 1796 The vaccine was developed further and rolled out acrossthe world and smallpox ceased to be endemic. This established the ability of vaccinations to overcome disease, giving us hope that further advancements may provide us with herd immunity to many more sicknesses Currently, the existence and spread of disease is being heavily mitigated by the existence of vaccinesand it is therefore arguable that future

advancements in medicine may lead to the elimination of disease and that the eradication of smallpox wasthe first of many tocome.

On the other hand, there is a vast variety of diseases and, despite improvements in treatmentsandvaccines,it isunlikely that we will be able to exterminate all known human pathogens Disease causing organisms are constantly mutating with the aim of increasingtheir lifespan insideand outsideof the body. The COVID 19 virus mutated several times over the course of two years, becoming increasingly transmissible The method used to cope with the mutations is inefficient: each variant requires a different vaccine followed by several booster jabs which only provide immunity for six months. This evidence implies that by attempting to reduce the spread of disease,humanswill be left with more transmissible and potentially more dangerous variants This ability to mutate rapidly gives pathogens a significant evolutionary advantageover humans,and for that reason diseases are something that humankind is forced to co exist with Although we can inhibit the spread of illnesses, it is unlikely that we will eradicate diseaseasawhole

To conclude, although it is possible for a disease to be eradicated, there is far too much variation between transmission, zoonosis, and effective cures between types of diseases, for vaccines to be the sole methodof achievingglobal immunity.

News

Can Mistletoe Berries be Used as a Superglue?

Marco Cina Rabin

Mistletoe is an evergreen plant with white berries that parasitically grows in the branches of certain trees Each mistletoe berry can produce up to two metres of a gluey thread called viscin, which allows the seeds of this parasitic plant to stick to and infect host plants.Until now,no onehasfully investigated potential medical or technical usesof theglueitself

A recent paper from McGill University and the Max Planck Institute of Colloids and Interfaces suggests that through simple processing, viscin's ultra stiff flexible fibres, which adhere to both skin and cartilage as well as to various synthetic materials, could have a range of applications in both biomedical and future technologies The paper also suggested that viscin could be stretched into thin films or assembled into

How do Hypergiants Die?

Arjun Bubbar

On June 16th 2022, students at the University of Arizona recorded the death of a hypergiant in the Milky Way known as VY Canis Majoris. It stood more than 3,000 light years away from the Earth With an estimated mass of 17 times the Sun and a radiusof 1,420 timesgreater ? namely 980 million kilometres ? it was considered one of thelargest starsin theMilky Way Tracing the molecular emissions in the outflows around the red hypergiant allowed them to

3D structures. They believe that this means the substance could potentially be used as a woundsealant or skincovering

The universitiesstill have alot of research to undertake in order to try to replicate the process. However, given the excellent properties of viscin, and the fact that mistletoe plants are abundant and biodegradable, these findings suggest that thisremarkableplant might beutilised for its potential commercial value asan adhesive or superglueinthenear future.

obtain thefirst detailed 3D map of thestar's envelope.When hydrogen isexhausted from stars,it indicatesthe final stagesof their life as their hydrogen and helium cores tend to burn. Supernovae, the brightest and most powerful explosions known to man, despite only occurringamongst thelargest stars,are usually not visible in our galaxy owing to dust blocks Astronomersestimate that only one or two supernovae will light up in a century

A New Black Hole?

Amaan Aziz-Khan

On May 12th 2022, a team of astronomers operating the Event Horizon Telescope released an image of the black hole at the centre of the Milky way, named Sagittarius A* (Sgr A*). The black hole M87 previously imaged at thecentreof thegalaxy,shown on the left of the image, is 2,000 times bigger than Sgr A*, but is also 2,000 times further away from Earth, allowing for a similar resolution in both images. The reason this image is such a big deal is that M87* was an unusually large black hole,whereas Sgr A* is much smaller and similar to the many black holes at the centre of other galaxies, meaning we have a much greater idea as to what theseother black holeslook like.

The colour we see in the image is produced by the swirling superhot clouds of gas orbiting Sgr A* moving at incredible speeds. This image is striking evidence of a supermassive blackhole at the centre of our galaxy and thisisthe first time we have been able to see it, rather than only observe the effectsit hasonitssurroundings.

Do Mummies Still Contain Ancient Strains of Bacteria?

Marco Cina Rabin

For the first time, researchers have reconstructed the DNA of an ancient strain of E. coli To find the bacterium, the team turned to the mummified remainsof a group of Italian nobles who were believed to have lived in the 16th century Examining the mummy's gallbladder, the team was able to detect E. Coli, ?an opportunistic pathogen?(a pathogen that likely won't cause disease in a healthy host,but that can causediseasein an immunocompromised host).Usingfragments from a gallstone, the team identified the E. coli and reconstructed its genome. This ancient strain is quite similar to a contemporary strain

By studying ancient strains of E. coli, the researchers say we can learn more about its evolution Today,for instance,somestrainsof E. coli are becoming increasingly resistant to antibiotics. The researchers hope that in the future, they may be able to explore how other 'hiddenpathogens' haveevolved

Physics

The Doppler Effect

Adrien Durantel

In the year 1842, Christian Doppler first noted the phenomenon that is now referred to as the ?Doppler effect,?paving the way for substantial improvements in fields including robotics,medicine,andastronomy

The Doppler effect is the apparent change in frequency and wavelength of waves whenever the source of the waves is moving relative to an observer. When a source of waves is itself moving towards an observer, each new waveisemitted at adistancecloser to the observer, causing a compression of waves, producing a higher frequency The opposite istrue when the source of the wave is moving away from the observer, with a stretching out of waves and a decreased frequency

This equation can be used for electromagneticwaves:

Where ? = source wavelength, ?? is the change in wavelength recorded by the observer, f = source frequency, ?f = change in frequency recorded by the observer, v = magnitude of relative velocity between the source and the observer and c = speed of light

The equation can be used only for galaxies with speeds significantly lower than that of light

TheDoppler effect istheresult of themotion of the source, the observer, or even that of the medium depending on the type of wave (the phenomenon occurs for any type of wave)

Mathematically, the Doppler equation is givenby:

Where f0 = observed frequency, fs = actual frequency of waves,v=speed of sound waves in medium, v0 = observer velocity, and vs = wavesourcevelocity

The Doppler effect is used in innumerable applications including measuring the speed and direction of blood flow in organisms, echocardiograms,andsatellites. When looking at the absorption spectrum of a specific element and comparing it with the same spectrum observed in light from a faraway galaxy, we can detect any differences in the wavelengths of the absorption lines. These result from the relative motion between the galaxy and Earth If thedistancebetween thegalaxy and Earth increases,there will be the perception of a decreased frequency of the light (?redshift?as wavelength increases, shifting to the red end of the visible light spectrum). Conversely, if the distance between the galaxy and Earth decreases,therewill be the perception of an increased frequency of light (?blueshift?as wavelength decreases, shifting to the blue end of the visible light spectrum)

In the 1920s, Edwin Hubble analysed the Doppler shift inabsorptionspectraof distant

galaxies, discovering that light from most galaxies was red-shifted and that the further the galaxy was, the greater the observed red shift This is because the universe is expanding with the distance between galaxies increasing (the further apart two galaxiesare,the greater the rate at which the distance increases). This technique can also determine the speed of stars and galaxy rotations It is worth noting that for galaxies the cosmological redshift is used rather than the Doppler redshift as the wavelength at which radiation was originally emitted is lengthened as the wave travels through expanding space. Cosmological redshift considers stationary emitters and observers in expanding space (unlike Doppler shift, which requires at least one of theobserver or emitter tomove).

Some typesof weather radars locate areas of precipitation using the Doppler effect The radarstransmit microwaves,and these arereflected off precipitation and back to a receiver. The wavelength of reflected waves will be Doppler shifted depending on the relative motion of the weather system and consequently, the path of the weather system can be tracked. Modern weather radars are extremely sensitive, detectingthemotion of individual droplets, measuring the intensity of the

precipitation,and determiningwhat typeof precipitation is falling (rain, snow, or hail) Similarly,thespeed of atennisball or of any moving object can be measured from the Doppler shift of the microwaves reflected off theball.

Doppler spectroscopy is a technique used to detect periodic velocity shifts in the stellar spectrum caused by an orbiting planet Starlight is analysed for evidence that astar isbeingpulled back and forth by the gravitational pulls of orbiting planets. Observations are made of the spectrum of emitted light to detect periodic variations in the star?s spectrum (the wavelength of someof thecharacteristicspectral lineswill increase and decrease regularly over a period of time if an orbiting planet exists. The mass of the planet can then be calculated though the accuracy of this value depending on the inclination of the planet?s orbit) This method?s limitations include the existence of variable stars and that the gas surrounding some stars can expandandcontract

In conclusion, the Doppler effect has undoubtedly been at the forefront of scientific advances since it was first understood and will continue to be so for centuriestocome.

Quantum Computing: Separating Fact from Myth

Danny Cui

In a paper published in Nature in October 2019, Google announced that it had demonstrated quantum supremacy. Their cutting edge quantum processor, codenamed Sycamore, had performed a task that would take a state of the art classical supercomputer approximately 10,000 years in a mere 200 seconds. This has

unquestionably raised the existing excitement surrounding the technology to a brand new level. However, the hype surrounding this exciting technology is often shrouded in myth. It is also not helped by countless news headlines' screaming the advent of the "Imminent Quantum Computing Apocalypse" following the arrival

of the Google paper. These accounts are greatly exaggeratedanddonot tell thewhole story ? that the task performed by Sycamore to demonstrate "quantum supremacy" is of no actual practical application and will not doom all of our encryption soon (although this is something to be aware of in the long term) None of the currently available demonstrations of "quantum supremacy" are applicable to any real practical computing situations, and the majority of these do not even use any input data.

To separatethemyth fromthefacts,weneed to delve into some of the physicsbehind this technology. The basic unit of information that a quantum computer operates on is a qubit A qubit can be any two state quantum system. Common examples include the spin of an electron,wherethetwo possible states are up or down; or the polarisation of a photon, where the two states are vertical polarisation and horizontal polarisation Like itsclassical counterpart,the classical bit, the two states of a qubit correspond to the values1 and0 Unliketheclassical bit,aqubit can be in a superposition of its two states 1 and 0. This is where a lot of the confusion about quantum computers comes from In many popularised science articles online, superposition is commonly described as ?being in all possible states at once?, and the strength of quantum computing is described as ?being able to compute all possible answers simultaneously? This is misleading and overly simplified. What the superposition of a qubit really means is that thequbit isin a"complex linear combination" of the states 1 and 0, which are denoted as two vectors, |1? and |0? respectively. The state of a qubit is usually represented as a vector, where the states |1?and |0?are the basis.The state can hence be represented as a sum of |1? and |0?, each weighted with somecomplexcoefficient,for example:

Where|x?isatypical stateof aqubit,and the coefficients a, and b are referred to as amplitudes of |0?and |1?. The square of the absolute value of the amplitude of a basis state gives the probability of obtaining it when measured Continuing the example above, the probability of measuring |0? would be |a|2 . Amplitudes can constructively and destructively interfere, much like amplitudes in a wave Measuring the qubit will only return one of the states|0?and |1?, whose probabilities are given by the square of theabsolutevalueof their amplitudes

For a computer to be useful,it needsto have a measurable output But because we can obtain only one of the basis states after measuringaqubit,thismeansthat measuring an equal superposition of "all possible states at once" would really return one random answer,and to obtain all possible answers,in this case, is the equivalent of brute forcing your way through,which isnot efficient at all The key to efficient quantum computingisto devise an algorithm that will constructively interfere to increase the likelihood of a 'right answer', and destructively interfere to decreasethechanceof a'wronganswer',and do this faster than a classical computer This is often tricky and especially since the answer isoftennot knowninadvance

Existingquantum algorithms,such astheone devised by Shor (which performs prime factorisation almost exponentially faster than the current best classical algorithm),do this by exploiting specific mathematical structures in these problems Only a narrow range of algorithms like these can take advantageof quantumcomputation.

To be able to break most of the encryption used today,we would need to have quantum computers able to effectively implement Shor?salgorithm Accordingto researchersat Google and Sweden?s KTH Royal Institute of Technology, for a quantum computer to be able to break a 2,048 bit RSA encryption, a

typical encryption used today, it would take eight hours on a computer with 20 million qubits Most quantum computers as of present use fewer than 100 qubits, with larger quantum computers using just over 100 It will take decades until we will have quantum computers with 20 million qubits, and even longer for them to be commercially available Mostly, this is because qubits are fragile and prone to error. One of the most prominent causes of error is decoherence ? where qubits are prematurely measured owing to unwanted interactions with the environment Thiscausesqubitsto lose their ?quantum ness?, taking on one of the two states |0?and |1?, and not a combination of thetwo

A way of mitigating the effects of decoherence is through what is called ?Quantum Error Correction? However, this often involves redundancy, where several physical qubits are used to logically represent a single qubit These physical qubits are often entangled, meaning that a change to the state of one of the qubits instantaneously changesthestateof therest of them Through the ingenious use of

Centripetal Force

Max Satchell

Centripetal force causes an object to travel in a circular path. It is often misunderstood but all too prevalent in our day to day lives Why do planets stay in orbit?And how does a loop-the-loop work? These are all questions that can be answered by understanding the centripetal forces present.

First of all we must ask ourselves the question:what isacentripetal force?

The answer is that there is no force simply called ? centripetal force? in the same way

quantum gateswhich can comparethestates of the entangled qubits without actually measuring them, an error can be identified and corrected However, the redundancy means that we would need many times the number of qubits that an algorithm logically requires, which increases the difficulty of implementation There are other methods of reducingtheerrorsin qubits,such as making them as stable as possible, which often involveskeeping the device at atemperature just above absolute zero, or even a completely different but more stable approach, such as topological However, keeping objects at a temperature close to absolute zero is hard, and building topological quantum computing hardware hasbeenareally bigchallenge.

Even though quantum computing is an exciting field of new technology, it is important to separate the myth from facts. However, even looking past all the hype and myth surrounding this subject, quantum computing will undoubtedly be ground breaking in its potential uses and applications, and will likely be a new and revolutionary tool in many different fields.

that a certain force may be called tension or weight. The best way to understand this is perhaps with an example Imagine you are whirlingaround astringwith amassattached to itsend in theair.Why doesthe massmove in a circular fashion?We should consider the forcesactingonthemassat thismoment

The important force is the force denoted R. Thisrefersto the tension in the string In this scenario we say that the tension in the string actsasthecentripetal force.Note that at any given moment the tension isalwaysdirected

towards the centre of the circle of motion and that the direction of motion, v is always perpendicular to the tension R It is the combination of these two properties that causesthecircular motionof themass.

Now let us consider why the planets of our solar system remain in orbit around the Sun In thiscasethe weight of each planet actsas the centripetal force At any given time each planet wants to travel in a straight line in some general direction away from the Sun. However, the gravitational pull of the Sun creates a force (the centripetal force) on these planets which always acts directly towards the Sun Therefore, no matter where a certain planet is in its orbit, it will alway be pulled into a curved path The International Space Station uses the exact same centripetal force in weight to stay in orbit aroundtheEarth

How about a more complex example, a loop the loop? The two forces acting on a carriage of a roller coaster at any given time are the normal contact force,exerted by the track on the carriage, and the weight of the carriage In thiscase,the forceswhich act as the centripetal force are actually always changing, depending on the position of the carriage around the track The key thing to understandisthat thecentripetal forcemust always have a constant magnitude, no matter where the carriage is, and must alwayspoint towardsthe centre of the loop. So,when thecarriageisat thebottom of the loop the loop, weight acts downwards, and the normal contact force acts upwards. At

this stage, the normal contact force acts entirely as the centripetal force, and for the centripetal force to have a constant magnitude, normal contact force must be at its greatest here But what about when the carriage is at the top?Here both weight and normal contact force act downwards,and we know that thecentripetal force must also act downwards, towards the centre of the loop. At thispoint,both weight and normal contact force act as the centripetal force, and the normal contact force is at its minimum so that the magnitude of centripetal force remainsconstant,or zero

Centripetal force is the reason why so many of the best childhood toys work. Swings, roller coasters, merry go rounds, as well as events like the shot put and hammer After all,it isessential for all circular motion.

Psychology

What is Addiction?

Varun Vashisht

Addiction, or at least the possibility of addiction, has become increasingly prevelant, with almost everyone being addicted to something, whether it be food, coffee, drugs, alcohol or video games But what actually causesthisaddiction,and how canwetry tostopour ownaddictions?

The NHSdefinesaddiction asthe inability to ?have control over doing, taking or using something to the point where it could be harmful to you? Whilst this certainly covers a lot of the common addictions well known to thepublicsuch assmokingand drinking,it also bringslight to other activitiesthat some peoplemight refer to asan addiction,such as work or even shopping Thisclearly indicates that it isn? t just chemical substances that cause an addiction In fact, the main culprit behind addictions is the reward circuitry withinthebrain.

When carryingout these actionsfor thefirst time, neurotransmitters such as dopamine and endorphins are released towards the reward centre within the brain via the mesolimbic pathways This novel feeling leads to a powerful feeling of pleasure. Naturally, this leads them to want to carry out that action multiple times afterwards to continue feeling that same pleasure. However, as they continue to repeat this over and over, the dopamine and endorphin receptors become less and less sensitive to the binding of their complementary neurotransmitters,resulting in a decrease in

pleasure for the person. Although it seems like it would demotivate them from doing that action further,it actually invigoratesthe person to repeat that action even more in an attempt to achieve that same feeling of pleasure they experienced when doing it for the first time Whilst the level of pleasure would be reached with enough dopamine or endorphins, this further desensitises the dopamine and endorphin neurotransmitters, decreasing the pleasure from performing that action to agreater extent.Thisresultsin aviciouscyclewheretheperson continuesto try to experiencethat pleasurefromcarrying out that action and never ends up receiving it owing to the continual increase in tolerance in the dopamine and endorphin receptors

Addictionscan haveprofound effectson the body which differ depending on the addiction. Some may face financial damage owing to uncontrollable spending habits on addiction related products (eg cigarettes); even the act of buying can trigger the reward pathway Substance misuse often has physiological effects, from emphysema caused by damage to the alveoli from smoking, to liver damage from excessive alcohol consumption Addiction also has mental effects,such asan increased level of impulsivity and a diminished level of appropriate decision making Attempting to stop the addiction generally results in withdrawal symptoms such as restlessness,

fatigueand anxiety,all of which usually cause arelapseintotheaddiction

Whilst it does seem that you simply cannot escape your addiction, there are several things that can help Some products such as nicotine patches contain the chemical that releases dopamine without the harmful side effectsthat comewith it Behavioural therapy can provide awareness of the cause of addiction to the person and givescounselling to alleviate the symptoms that come with it such as anxiety and depression. Finally, certain medications can be taken that mimic the effects of the addictive drug in order to ease withdrawal symptoms.

Does language Affect the Way in Which We Think?

Shivan Arora

For millennia people have questioned whether language affectshow we think,and many theories have been proposed. Most popularly, there is the Sapir Whorf Hypothesis which is split into two subtheories: linguistic relativity and linguistic determinism. Linguistic relativity posits that different structures in different languages lead to non-linguistic cognitive differences and responses to the world These non linguistic cognitive differences can be defined asdifferencesin processesin the brain that are not related to the understanding and use of language within it ? such as recalling a mathematical formula. Linguistic determinism, on the other hand, suggests that the language we speak determines our world view; given how strong of an effect it suggests, we can disregard it, at least until linguistic relativity

is found to be true.The influence of language can be examined in the realmsof colour,time, space, orientation, and also in more abstract concepts,suchasagency.

Firstly, we can examine the matter of colour Research has been conducted on the Himba people, a semi nomadic Namibian tribe who live isolated from modern developments and have chosen to live traditionally. The people of the Himba tribe, who have no distinction between green and bluein their language,and no word for blue, took far longer to distinguish bluefrom aset of green than their English counterparts However, on the other hand, due to their vast vocabulary for green colours,they could more quickly distinguish a different shade of green from a set of greens. This suggests that they can indeed see the colour blue, however, the fact that their language doesn? t have an outright word and

distinction for blue also appears to have influenced the way in which they perceive colour, a non-linguistic cognitive process. Thisthusdemonstratessupport for linguistic relativity

Lookingat time,astudy of Mandarin-English bilingual speakers,and theway in which they organise time psychologically, was conducted and produced fascinating results. In Mandarin, certain spatiotemporal constructions exist, which use spatial markersto reference time,such as? ? ? ? (shàng ge x?ng q?), which literally means ?up week? , but is translated as ?last week?They took photographs of mainstream Chinese actor Jet Li,andfamousAmerican actor Brad Pitt, and asked Mandarin-English bilingual speakers to arrange the photos in chronological order They found that participantswere more likely to organise Jet Li with a vertical Chinese language influenced timeline, whereas they weremorelikely to organiseBrad Pitt with a horizontal English timeline This demonstrates a clear influence of language upon thought, as the non-linguistic process of organising time is influenced by the languageassociatedwitheachactor

Many languages have grammatical gender that is seemingly randomly assigned For example,?DasMädchen?in German,meaning ?the girl? , is neuter This begs the question, 'does the grammatical gender of a noun give a gendered perception?A study carried out in 2003 found that German speakers associated feminine gendered nouns with stereotypically feminine attributes, and vice versa for masculine nouns The same was found in Spanish speakers Spanish tended to say 'sturdy' and 'towering', but German tended to say 'beautiful' or 'elegant' The same occurred the other way round: the

word for 'key', masculine in German, and feminine in Spanish, was described as 'golden' or 'intricate' in Spanish, and 'heavy' and'serrated' inGerman

Finally,we can examine the abstract concept of agency. Varying languages often have vastly different structures, for example, Spanish often employs the passive ?se? to express an accidental occurrence, rather than immediately directing the blame to the person The following may be a likely occurrence: ?se rompió el florero?(the vase broke), rather than ?rompiste el florero?(you broke the vase) A study found that when comparing eye witness memory of events between English and Spanish speakers, both groups described intentional agents of the action asagents,and had strongmemoriesof these agents However, English speakers tended to remember theagentsof accidental events better than Spanish speakers, reflecting the difference in structure for accidental events specifically, whereas in Spanish the agent is often unspecified, suggesting an effect of the language they spoke upon the way they perceived the event

Overall,studiessofar havefoundlanguageto have influenced the way in which people think, albeit mostly in the specific scenarios of colour discrimination and time organisation This raises issues for real life implications of such an influence: given the general weakness of experimentally recorded effects, it is more reasonable to suggest that language does affect our thoughts and perceptions, however in a day to day context,theeffect is negligible