YSJ Issue 1.2

LetterfromtheEditor-In-Chief

AWordofWelcome

Fromastudent’sstandpoint,scienceiscertainlyatoughsubject.Withclasseslike AdvancedPhysicsandHonorsChemistrytocontendwith,it’snowonderthatthe sciencesareoftenseenaswork.Andyet,atitscore,scienceisaboutcuriosityand discovery.TheYouthScienceJournalisacollectionofacademicarticles,writtenbyyour peers,withthehopeofreawakeningthatinnatedesiretolearn.So,ifsubjectsranging frominterstellarradioemissionstothegeneticsresponsibleforlearningalanguage interestyou,readahead ajourneyofdiscoveryawaits.

RyanMin EditorinChief

Potatoes:PoisonorMedicine?

Author:RyanMin.

Edit:JamesL.

Abstract

Potatoes.Theyareastaplearoundtheworldandarepresentinavarietyofdishes.Infact,they havebecomeincreasinglypopularindevelopingareasduetotheircheapcost.However,ifleft untouched,thesepopularvegetablescanturngreen,withsproutsoftenappearingalongapotato’s surface.Recentstudieshaveproventhatthesepotatoescontainhighlevelsofglycoalkaloids,a compoundwhichispoisonousinhighconcentrations.Infact,therehavebeenmultiple occurrencesinwhichconsumptionoftheseso-called“poisonouspotatoes”hasresultedindeath. However,glycoalkaloidshavealsobeenshowntoexhibitnumerousbeneficialtraitstohuman health,includingantitumorpropertiesthatcouldbeusedtocombatcancer.Thisposestwo questionstobeanswered.Firstly,howdoestheglycoalkaloidconcentrationofapotatoimpactits abilitytobepoisonoustohumans?Andsecondly,howcantheglycoalkaloidspresentinpotatoes beharnessedtobenefithumanity?

Keywords:

Glycoalkaloids;antitumor;α-solanine;α-chaconine;tuber;eyes;highperformanceliquidchromatography (HPCL);bioaccumulation;invivo;invitro;apoptosis;anti-inflammatory

Introduction:

Potatoes(Solanumtuberosum)havebecomeprevalentinhumansocietyduetotheirhighnutritiousvalue andeaseofgrowing.Thesequalities,alongwiththecheapcostofpotatoes,havemadethemquite popular potatoesarethethirdmostimportantcropintheworld,withmorethanabillionconsumers worldwide[1].PotatoesarecommonlyconsumedintheformofFrenchfries,chips,andotherpotatobasedfoods.However,potatoesareknowntocontainglycoalkaloids,steroidswhichareproducedforthe plant’sdefense.Glycoalkaloidshavealsobeenobservedtoaccumulateinpotatoesduringgrowthand post-harvest[3].Iftheglycoalkaloidconcentrationbecomeshighenough,thesechemicalscanbecome harmfultohumans,makingglycoalkaloidsaseriousconsiderationinregulatingtheconsumptionof potatoes[2].

GlycoalkaloidsinPotatoes:

Glycoalkaloids,particularlyα-solanineandα-chaconineinthecaseofpotatoes,aresynthesizedthrougha biosyntheticprocessfromcholesterol[3].Theyconsistofaglyconesolanidinebondedtoatrisaccharide, whichconsistsofgalactose,glucose,andrhamnoseinbothα-solanineandα-chaconine.α-solanineandαchaconinemainlyserveasstressmetabolitesandphytoalexins,whichhelpprotectpotatoesfrombacteria, fungi,viruses,insects,andanimals[2,3].Glycoalkaloidsarestructurallystable,limitingtheeffectivenessof dehydrating,microwaving,boiling,orfreeze-dryingpotatoestoreducetheirglycoalkaloidcontent[3].

Bothα-solanineandα-chaconinearesynthesizedfromcholesterol,whichisproducedstartingwithacetylCoA.Cholesterolisthenmodifiedbyglycoalkaloidmetabolismenzymesthroughoxidation, hydroxylation,andtransamination,creatingsolanidine.Solanidineglycosyltransferaseenzymesthen modifysolanidine,producingtheglycoalkaloidsα-solanineandα-chaconine[9].Althoughα-solanineand α-chaconineaccountfor95%oftheglycoalkaloidcontentofapotato,thereareotherglycoalkaloids present[3].Theseincludeβ-andγ-solanines,β-andγ-chaconines,5-β-solanidan-3-aolanddemissidine, andα-andβ-solamarines[8].Glycoalkaloidstendtobefoundinhigherconcentrationsintheskinofthe potato,andaredistributedunevenlythroughoutthepotatoplant,asshowninFigure1.

Figure1:Glycoalkaloidconcentrationsindifferentpartsofapotatoplant.CredittoDuke GekongeOmayio,GeorgeOokoAbong,andMichaelWandayiOkoth,UniversityofNairobi, sourcedfromhttps://www.foodandnutritionjournal.org/volume4number3/a-review-ofoccurrence-of-glycoalkaloids-in-potato-and-potato-products/.

Glycoalkaloidconcentrationsalsotendtobehigherinandaroundtheeyes,woundedareas,andsprouts ofthepotato[3].Lightexposureincreasestheformationofchlorophyll(agreenpigment)and glycoalkaloids;thus,theglycoalkaloidconcentrationofapotatocanberoughlyestimatedbasedonits color,withagreenerpotatolikelyindicatinga higherconcentrationofglycoalkaloids[4].

Althoughthebodyofthepotatotendstohavealowerglycoalkaloidconcentrationthantheeyes,stems, andskin,thisdoesnotnecessarilymeanthefleshissafeforconsumption[4].Forinstance,theaverage potatotubercontains12–20mgkg-1 ofglycoalkaloids,agreentubercontainsanaverageof250–280mg kg-1,andthegreenskinofatubercontains1500–2200mgkg-134ofglycoalkaloidsonaverage[3].

GlycoalkaloidToxicity:

Consumptionofhighconcentrationsofglycoalkaloidsisknowntohaveanumberofharmfuleffects. Studiesusingtastepanelshavereportedthatsubjectsexperiencedabittertasteandburningsensationin themouthuponconsumptionofpotatoeswhoseglycoalkaloidconcentrationsexceeded14mg/100g and22mg/100gfreshweight,respectively[5].

Responsestoglycoalkaloidpoisoninggenerallyincludegastrointestinalandneurologicaldistress,suchas headaches,vomiting,andflushing[5].Severecases,suchasa1979occurrenceinSouthLondon,caused 78schoolboysandmonitorstoexperiencevomiting,abdominalpain,diarrhea,depressionofthenervous system,and,insomecases,putvictimsinacomatosestatewithconvulsivetwitching,violentfevers,and lingeringhallucinations[6].Glycoalkaloidscanbioaccumulateinthehumanbodyfollowingdaily, prolongedconsumptionofglycoalkaloid-containingfoods,andpersistinthebodyfor24hoursafter ingestion[10].Thetoxicityofglycoalkaloidstohumansmaystemfromtheiranticholinesteraseactivity anditseffectonthecentralnervoussystem,aswellasbydisruptingcellmembranesoforgansinvolvedin thedigestivesystem[8].

Inordertoascertaintheconcentrationofglycoalkaloidsinpotatoes,highperformanceliquid chromatography(HPLC)andHPLCwithelectrosprayionizationandtandemmassspectrometryare oftenused[5].HPLCcanbesubdividedintotwophases,themobilephaseandthestationaryphase. Duringthemobilephase,asolventseparatescomponentsofaliquidsample,whichisthendeliveredtoa columnandthentothedetectorbythesolventdeliverypump.Duringthestationaryphase,someofthe liquidsampleisinjectedintothecolumn,whichseparatesthecompoundspresentinthesample.The compoundsarethentransferreddownstream,wheretheyaredetected,identified,andquantifiedbythe detector{7].ThisprocessisdepictedinFigure2.

MethodssuchasHPCLareusefulforstudiesofglycoalkaloidcontentinpotatoes,whichcanthenbeused toimprovefoodsafety.Forexample,theEuropeanFoodSafetyAuthority’sPanelonContaminantsinthe FoodChain(CONTAM)conductedexperimentstomeasurethedifferencebetweentheinitialandfinal glycoalkaloidcontentsofpotatoesafteravarietyofdifferentmethods,includingmultiplecombinationsand formsofpeeling,boiling,blanching,steaming,frying,baking,andmicrowavingpotatoes.Theresults demonstratedtheefficacyofmanyofthesemethodsatreducingglycoalkaloidlevels,inparticular,french-fry processing,potatochipprocessing,andmanualpeeling[11].Inconjunctionwithfurtherstudies,these resultsprovideausefulguidelinetoreducingglycoalkaloidsinpotatoesandthusloweringtheriskof contractingglycoalkaloidpoisoning.

PotentialBenefits:

Althoughpoisonoustohumans,glycoalkaloidshavedemonstratedanumberofbeneficialeffectsonthe humanbody.Perhapsthemostpromisingareaofstudyisthatofglycoalkaloids’antitumorproperties. Whenexposedtoglycoalkaloidsproducedinpotatoesortheirhydrolysisproducts,thegrowthoftumorcells bothinvivoandinvitrowasinhibited[12].

Thispropertyhasbeenobservedmultipletimesinα-solanine,which,forexample, inhibitedgrowthand inducedapoptosisincancercellssuchashumanliver(HepG2)andcolon(HT29)cancercells[13].This propertyhasalsobeenobservedinα-chaconine,which,forexample,wasfoundtocauseapoptosisinHT-29 humancoloncancercellsbyactivatingcaspase-3,aproteasethatcausescelldeath,andbyinhibiting extracellularkinasephosphorylation[14].Studieshavealsoshownthattheantitumorpotencyofthese glycoalkaloidsappearstobeconcentrationdependent[14].Althoughfurtherstudiesarerequired,these initialexperimentssuggestthatlowlevelsofglycoalkaloidsinpotatoescouldpotentiallybeutilizedfor cancertreatment.

Figure2:AdepictionofthephasesofHPCL.CredittoShimadzu,sourcedfrom https://www.shimadzu.com/an/service-support/technical-support/analysis-basics/basic/what_is_hplc.html.

Glycoalkaloidshavealsobeenshowntohaveanti-inflammatoryproperties.Inone experiment,theadditionofglycoalkaloidsandpotatopeelextractstoJurkatandRaw264.7 mousemacrophagesintandemwithstimulantsledtoreducedproductionofinterleukin-2 andinterleukin-8,bothofwhichareinvolvedintheinflammatoryprocess[15].Further explorationofthispropertymaybeusefulinpreventinginflammatorydiseases.

Conclusion:

Asoneofthemostprevalentandconsumedagriculturalproductsintheworld,potatoesareanearlyessentialpartofhumanity’sfoodnetwork.Glycoalkaloidsinparticular,whichareresponsibleforthe greeningandappearanceofeyesthatoccurinpotatoes,areatargetforfurtherresearchduetotheir manyproperties,bothharmfulandbeneficial.Inhighconcentrations,potatoglycoalkaloidsare poisonousandcancausesufferinganddeath.However,inlowconcentrations,glycoalkaloidshave beneficialantitumorandanti-inflammatoryproperties,andhavethepotentialformore.Therefore,itis crucialtocontinuetoresearchglycoalkaloids,bothtocreateaccurateregulationsregardingthegrowth, sale,andconsumptionofpotatoes,andtodevelopmedicalusesforglycoalkaloids.Investingin glycoalkaloidsmaybethekeytounlockingthesecretsofthepotato,loweringtheriskoffood poisoningfromtheworld’sthirdmostimportantcrop,andperhapsevenprovidingaless-intrusive formoftreatmentforcancer.

References

[1]PotatoFactsandFigures.InternationalPotatoCenter. https://cipotato.org/potato/potato-facts-andfigures/#:~:text=More%20than%20a%20billion%20people,in%20 many%20sizes%20and%20shapes.Retrieved05/22/2023.

[9]Arslan,AyşeKübraKaraboğaetal.(06/14/2018).αChaconineandα-SolanineInhibitRL95-2EndometriumCancer CellProliferationbyReducingExpressionofAkt(Ser473)and ERα(Ser167).NationalLibraryofMedicine.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024735/. Retrieved05/22/2023.

[2](09/16/2011).GlycoalkaloidsinFoods.Governmentof Canada.https://www.canada.ca/en/health-canada/services/foodnutrition/reports-publications/food-safety/glycoalkaloidsfoods.html.Retrieved:05/22/2023.

[3]OmayioD.G,AbongG.O,OkothM.W.(11/29/2016).A ReviewofOccurrenceofGlycoalkaloidsinPotatoandPotato Products.CurrResNutrFoodSci2016;4(3). http://www.foodandnutritionjournal.org/?p=3281.Retrieved: 05/22/2023.

[10]PeksaA.,LubowskaG.,AnilowskiK.,LisinskaG.,RytelE. (2006).Changesofglycoalkaloidsandnitratecontentsinpotatoes duringchipprocessing.JournalofFoodChemistry.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3201847/ Retrieved:05/22/2023.

{11]Schrenk,D.etal.(02/27/2020).Glycoalkaloidsinfeedand food.EuropeanFoodSafetyAuthorityJournal.

https://www.efsa.europa.eu/sites/default/files/consultation/cons ultation/contam-consultation-Glycoalkaloids-feed-food.pdf. Retrieved:05/26/2023.

[4]Pei,DianaM.AreSproutedPotatoesSafetoEat?National CapitalPoisonCenter.https://www.poison.org/articles/aregreen-potatoes-safe-to-eat191#:~:text=Potatoes%20contain%20two%20kinds%20of,plants% 20and%20is%20not%20toxic.Retrieved:05/22/2023.

[5]Barceloux,DonaldG.(2009).Potatoes,Tomatoes,and SolanineToxicity(SolanumtuberosumL.,Solanumlycopersicum L.).ScienceDirect.

https://www.sciencedirect.com/science/article/abs/pii/S0011502 909000340?via%3Dihub.Retrieved:05/22/2023.

[6]Smith,Annabelle.(09/2007).HorrificTalesofPotatoesThat CausedMassSicknessandEvenDeath.Smithsonian.

https://www.smithsonianmag.com/arts-culture/horrific-tales-ofpotatoes-that-caused-mass-sickness-and-even-death-3162870/. Retrieved:05/22/2023.

[7]WhatisHPCL(HighPerformanceLiquid Chromatography?).Shimadzu. https://www.shimadzu.com/an/service-support/technicalsupport/analysis-basics/basic/what_is_hplc.html.Retrieved: 05/22/2023.

[8]FriedmanM.,McDonaldG.M.etal.(09/22/2010).Potato Glycoalkaloids:Chemistry,Analysis,Safety,andPlantphysiology. CriticalReviewsinPlantSciences

https://www.tandfonline.com/doi/abs/10.1080/0735268970970 1946.

Retrieved05/22/2023.

[12]Friedman,M.(2015)Chemistryandanticarcinogenic mechanismsofglycoalkaloidsproducedbyeggplants,potatoes, andtomatoes.JAgricFoodChem.

https://pubmed.ncbi.nlm.nih.gov/25821990/.Retrieved: 05/23/2023.

[13]LeeKR,KozukueN,HanJS,ParkJH,ChangEY,BaekEJ, ChangJS,FriedmanM(2004)Glycoalkaloidsandmetabolites inhibitthegrowthofhumancolon(HT29)andliver(HepG2) cancercells.JAgricFoodChem.

https://pubmed.ncbi.nlm.nih.gov/15137822/.Retrieved: 05/23/2023.

[14]Burgos,G.,ZumFelde,T.,Andre,C.,Kubow,S. ThePotatoandItsContributiontotheHumanDietandHealth. Springer.https://link.springer.com/chapter/10.1007/978-3-03028683-5_2#Sec18.Retrieved:05/23/2023.

[15]Kenny,O.etal.(12/02/2010).Anti-inflammatoryproperties ofpotatoglycoalkaloidsinstimulatedJurkatandRaw264.7 mousemacrophages.NationalLibraryofMedicine.

https://pubmed.ncbi.nlm.nih.gov/23454444/.Retrieved: 05/23/2023.

QUASARS of the Universe

Author: Adrian Mendez Edit: Delbert Tran

Quasarsaresomeofthemostdistant andluminousobjectsintheuniverse, andtheyhavelongbeenofinterestto astronomersduetotheirunique characteristicsandpotentialasprobes oftheearlyuniverseandgalaxy evolution.Inthisessay,wewillexplore thecurrentstateofourunderstanding ofquasars,highlightingkeydiscoveries andoutstandingquestions.

First,let'sbeginwithabrief overviewofquasars.Quasars,short for"quasi-stellarradiosources,"are thoughttobetheactivegalactic nuclei(AGN)ofdistantgalaxiesand theyarecharacterizedbytheir extremeluminosityandenergetic emissionsacrosstheelectromagnetic spectrum.Theenergythatpowers quasarsisthoughttocomefromthe accretionofmatterontoa supermassiveblackholeatthecenter ofthegalaxy,whichcanheatthe infallingmaterialtotemperaturesof millionsofdegreesandcauseitto emitcopiousamountsofradiation.

Overthepastfewdecades,ourunderstandingofquasarshasbeen greatlyadvancedbyanumberofkeydiscoveries.Oneofthemost importantofthesewastherealizationthatquasarsarenotlocated withinourowngalaxy,butareinsteadlocatedatvastdistances, billionsoflight-yearsaway.Thisdiscoverywasmadepossibleby thedevelopmentofnewtechniquesformeasuringthedistancesto quasars,suchastheuseof"standardcandles"likeTypeIa supernovaeandthecosmicmicrowavebackground.

Anothermajoradvanceinourunderstandingofquasarshasbeen thediscoverythattheyareassociatedwithsupermassiveblackholes. Bystudyingthespectraofquasars,astronomershavebeenableto measurethevelocitiesofthegasanddustswirlingaroundthecentral blackhole,andthesemeasurementshaveprovidedstrongevidence thatquasarsarepoweredbyblackholeswithmassesofmillionsor evenbillionsofsolarmasses.Theexistenceofthesesupermassive blackholeshasalsoledtothedevelopmentofnewmodelsforthe evolutionofgalaxies,whichsuggestthatthegrowthoftheblack holeandtheformationofthegalaxymaybecloselylinked.

Despitetheseadvances,therearestillmanymysteriessurrounding quasarsthathaveyettobesolved.Oneofthemostintriguingoftheseis thequestionofhowquasarscanshinesobrightlydespitebeinglocated atsuchvastdistances.Theenergyrequiredtopoweraquasaris enormous,anditisnotclearhowitcouldbeproducedsoefficiently. Onepossibilityisthattheenergyisgeneratedthroughaprocesscalled "spaghettification,"inwhichtheinfallingmatterisstretchedoutinto long,thinstrandsasitfallstowardstheblackhole.Anotherpossibilityis thattheenergyisgeneratedthroughthecollisionandmergerofblack

Oneofthekeywaysthatquasarsaredetectedisthrough theirradioemissions,whichcanbeobservedwithradio telescopesevenatgreatdistances.Inadditiontoradio emissions,quasarsalsoemitvisiblelight,andtheycanbe identifiedbytheirdistinctivespectra,whichare characterizedbystrongemissionlinesofhydrogenand otherelements.Thesespectracanbestudiedinmoredetail usingspectrographs,whichallowastronomerstoanalyze thewavelengthsofthequasar'slightandlearnaboutthe physicalconditionsinthequasar'senvironment,suchas thetemperature,density,andchemicalcompositionofthe surroundinggasanddust.

holes,whichcanreleasevastamountsofenergyin theformofgravitationalwaves.

Artificial Intelligence: The Nearing Future #1

Author:VeerChopra

Edit:DelbertT.&SunayanaA.

ArtificialIntelligence(AI),a remarkabletechnologicaladvancement, encompassesintelligentmachinescapable ofreasoninganddecision-making.It representsafieldthatstrivestoemulate human-likethinking,learning,and problem-solvingabilitiestotackle complexandprofoundchallenges.Within therealmofAI,twoprominentcategories emerge:weakAIandstrongAI.WeakAI denotesdevicesprogrammedforspecific tasks,whereasstrongAIconstitutes intricatesystemscapableofundertaking complexendeavorsautonomously. Undeniably,ArtificialIntelligencewields significantpowertoshapethefuture.

TheintricatenatureofAIstemsfromits multifacetedmechanisms,whichareintegralto itsfunctionality.Machinelearningandneural networksserveastheprimarytechnologies poweringAI.Machinelearningleveragesthe notionthatsystemscanutilizedatatoestablish relationshipsandgenerateoutcomeswithout humanintervention.Thisconceptfinds applicationinvariousdomains,includingbig dataandpersonalizedadvertisements encounteredduringGooglesearches,where patternrecognitionplaysavitalrole.Neural networks,oftenregardedasthebrainofthe system,employnodes machineequivalentsof neurons toidentifypatterns,learnfrom them,andenhanceoverallperformance.These networksassumeacrucialroleinoptimizing largerinterconnectedsystems.

TheevolutionofAIhasbeenremarkablethroughout history.Itsinceptiontracesbacktothe1950swhenAlan Turingpresentedhispaper,"ComputingMachineryand Intelligence."However,progressremainedlimiteddueto theexorbitantcostsassociatedwithcomputersatthattime. Subsequently,significantstridesweremadethrough initiativessuchastheDartmouthSummerResearchProject onArtificialIntelligenceandtheDefenseAdvanced ResearchProjects,fuelingthegrowthofAI.The1980s witnessedtheadventof"deeplearning,"atechniquethat harnessespatternrecognitionandenablescomputersto learnthroughexperience.Astonishingachievements,such asdefeatingchesschampionsandimbuingrobotswiththe abilitytoexhibitemotions,furthershowcasedthepotential ofAI.Presently,wewitnessthetangiblemanifestationsof AI'sprogress,fromadvancedchatbotslikeChatGPTtothe developmentofself-drivingcars.Undoubtedly,AI's continuedadvancementsholdimmensepromiseand potential,offeringtheworldcountlesspossibilities.

Inconclusion,ArtificialIntelligenceemergesas acaptivatingfieldwiththepowertoreshape ourfuture.Itscomplexityliesintheintricacies ofitsmechanisms,predominantlydrivenby machinelearningandneuralnetworks.The historicalprogressionofAIillustratesits transformativepotential,fromitsearly beginningstoitspresent-dayaccomplishments. Withcurrentadvancementssuchaschatbots andself-drivingcars,itbecomesincreasingly evidentthatAIispoisedtorevolutionize variousfacetsofourlives.Aswelookahead,the limitlesspossibilitiesandprofoundimpactofAI beckonustoexploreitsvastcapabilitiesand harnessitspotentialforthebettermentof society.

Artificial Intelligence: The Nearing Future #2

Mankindhasseencountlessinventions throughouthistory;withthecontendersfor“the greatestinvention”beingoneofthreeitems:the wheel,thepress,thetelephone.However,inthelast decade,possiblythefittestcontenderhasemergedfor thetitleofmankind’sgreatestinvention AI.AI,or artificialintelligencecanbethoughtofasamachine thatcanreasonandmakedecisions.Comparabletoa humanmind,AIhasbeendevelopedtoretaincritical thinkingandproblem-solvingskillsets,closingthe gapbetweenthehumanandmachinebrain.Witha predeterminedmindthatcanstorelimitlessamounts ofinformationaccurately,artificialintelligencecould besaidtosurpasseventhegreatestmindintermsof recollection,andinthenearfuture,maybeeven problem-solving.

Artificialintelligencecanbefundamentally categorizedintotwoclusters:weakandstrong.Weak AI,asthenamesuggests,hasaweak“stateofmind” sotospeak,andcanonlyexecuteactionsthatare directlywrittenandprogrammedwithinits“mind.” OpposingtheweakAIisthestrongartificial intelligence,mostofwhichhasbeendeveloped withinthelastdecade,whichcanbetrained,or “taught,”todocomplextaskswithoutthehelpofa person.Strongartificialintelligencehasstrong implicationsfordevelopmentsinthenearfuture, whetheritbeforentertainment,careers,ormedical help,itwouldbenefitallrealmsofhumanendeavor.

ArtificialIntelligence(AI)isahighly intricatefieldcharacterizedbynumerous underlyingmechanismsessentialforits functionality.Theprincipaltechnologicalpillars supportingAIaremachinelearningandneural networks.Machinelearningoperatesonthe premisethatsystemscanautonomouslyestablish associationsandgenerateoutcomesfromdata, withouthumanintervention.Thisapproach findssignificantapplicationinbigdatascenarios, enablingpatternrecognitionalgorithmsto personalizeadvertisementsencounteredwhile browsingplatformslikeGoogle.Ontheother hand,neuralnetworks,akintothebrainofthe AIsystem,employnodesthatfunctionas machineequivalentsofneurons.Thesenetworks facilitatepatternclassificationandassimilation, playingapivotalroleinoptimizinglarger interconnectednetworks.

TheevolutionofAIhaswitnessedremarkable advancementsovertheyears.Itsinceptioncanbe tracedbacktothe1950s,withAlanTuringmaking notablecontributionsinhisseminalworktitled "ComputingMachineryandIntelligence."However, theprogressofAIduringthaterawashinderedbythe exorbitantcostsassociatedwithcomputers. Subsequentbreakthroughsinthefieldemerged throughsignificantinitiativesliketheDartmouth SummerResearchProjectonArtificialIntelligence andtheDefenseAdvancedResearchProjects, bolsteringAI'sgrowth.The1980switnessedapivotal turningpointwiththeemergenceof"deeplearning," atechniqueharnessingpatternrecognitiontoenable computerstolearnfromexperience.Thisepoch witnessedAI'sawe-inspiringfeats,including triumphsoverchesschampionsandthemanifestation ofemotionsinroboticsystems.Presently,AIhas reachedunprecedentedheights,withtheadventof cutting-edgeapplicationssuchasChatGPT,an advancedconversationalchatbot,andtherealization ofself-drivingvehicles.TheboundlesspotentialofAI ensuresthatitwillcontinuetoshapethefuture, offeringremarkablecontributionstotheworld.

Investigating the Genetics of Language Acquisition

Author: Nathan Min

Edit: James L.

ABSTRACT

A variety of genes play a major role in language learning and development. In this article, we hope to examine some of these genes and evaluate the extent to which language acquisition abilities are hereditary. To do this, we will first review the biological and neurological basis of language, as well as certain genes that play a role in language learning. We will then consider evidence suggesting the heredity of language. Finally, we will investigate whether certain genetic groups may be able to learn foreign languages easier due to their genotype.

Key Words: Second Language Acquisition (SLA)

INTRODUCTION

Second Language Acquisition: Nature or Nurture?

Despite the seeming omnipresence of Spanish classes in American high schools, surprisingly few Americans study or retain knowledge of foreign languages. In fact, a 2019 Washington Times article reported that while around 56% of Europeans are multilingual, according to the US Census Bureau, only 20% of Americans are multilingual [1]. The comparison between the United States and Europe is only one example of the global variation in bilingualism. While many factors, such as the environment one was raised in and one’s native language, play an important role in the ability to acquire a second language, a perhaps sometimes overlooked factor lies in genetics. In this report, we hope to investigate to what degree the ease of learning a second language is influenced by genetics. We shall begin with reviewing the biological and neurological basis of language.

The Neurological and Biological Basis of Language

Language is extremely complex. However, we can attempt to understand how human language works through reviewing the important areas of the brain in language acquisition and development. Wernicke’s area, located in the posterior superior temporal lobe, manages the understanding and comprehension of language, both through listening to speech and reading writing [2]. Disorders in Wernicke’s area (Wernicke’s aphasia) leads to retaining abilities to produce grammatically-correct sentences of proper length however, these sentences have little to no meaning [2]. Meanwhile, Broca’s area, located in the left hemisphere, controls the production of language, both oral and written [2]. Disorders in Broca’s area (Broca’s aphasia) leads to poor, labored articulation and speech [2].

Lastly, located near the occipital and parietal lobes is the angular gyrus, which is responsible for connecting language to auditory, visual, and sensory meaning [2]. An example of this could perhaps be when one associates the word “red” with a certain color, the word “loud” with a certain type of sound, and the word “smooth” with a specific tactile sense.

Furthermore, a variety of genes play an important role in language process and acquisition in humans. Here, we plan to go over two of these genes: the FOXP2 gene and COMT gene. The FOXP2 gene, located on chromosome 7, codes for a transcription factor called forkhead box P2 [3]. FOXP2 is integral to brain development and synaptic plasticity, which is the ability of the brain to change and reform new connections, or synapses between neurons, over time [3]. Researchers have also found that the forkhead box P2 protein plays a vital role in the proper development and acquisition of language [3].

Meanwhile, the COMT gene, located on chromosome 22, codes for the catechol-o-methyltransferase protein [4]. This protein is important in breaking down catecholamines [5]. Catechol-o-methyltransferase operates primarily in the prefrontal cortex, where it regulates the levels of various neurotransmitters including dopamine and norepinephrine and plays a role in functions such as inhibitory control and short term memory [4].

Figures 1 (left) and 2 (right): Positions of Broca’s area/Wernicke’s area and the angular gyrus, respectively. Image credit: OpenStax College, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons (1), Anatomography, CC BY-SA 2.1 JP <https://creativecommons.org/licenses/bysa/2.1/jp/deed.en>, via Wikimedia Commons (2)

There are two versions, one (membrane-bound COMT) which is present in the brain and a shorter version (soluble COMT) that is present in the blood, liver, and kidneys [4]. Such functions, particularly of the membrane-bound COMT enzyme, would clearly make the COMT gene an important candidate to study when exploring the genetics of learning a second language.

INVESTIGATING THE HEREDITY OF LANGUAGE AND ITS APPLICATIONS

Suggestions for a Strong Genetic Influence on Language Acquisition

A multitude of studies have suggested that language development, and more specifically language acquisition. For instance, in a study conducted by researchers at Osaka University the participants, all monozygotic or dizygotic elderly twins, were asked to give a verb based on text they read silently [6]. Low-gamma event-desynchronization (ERDs) in frequency range 25-50 Hz were then used to indicate brain activity in the left frontal region (the area responsible for human language) [6]. While the researchers concluded that both environmental and hereditary factors play a role in language learning, it appeared the “genetic control of ERDs” was virtually identical even between twins that were separated, suggesting the strong influence of genetics in language development [6]. Because the twins that were separated were raised in different environments, and the influence of the genes over the ERDs remained the same, it is likely genetics (the shared genetic material between the twins) played an important role in both language comprehension (reading the text) and generation (producing a verb).

Similarly, a study in the United Kingdom, conducted by Philip S. Dale, Nicole Harlaar, Claire M.A. Haworth and Robert Plomin, revealed similar results in regard to SLA [7]. In this study, 604 pairs of twins were evaluated, using the UK National Curriculum (NC) criteria, in three areas of performance: L2 (second language) abilities at 14 years old, L1 (native language) abilities based on teacher ratings at 14 years old, and L1 abilities based on a direct test online at 12 years old [7]. Correlations between twin pairs calculated for each measure [7]. Note that some twin pairs were identical, monozygotic (MZ) twins, meaning they shared 100% of genetic material [7]. Others were fraternal, dizygotic (DZ) twins, meaning they shared 50% of genetic material [7]. The study assumed that if correlations between MZ twins were larger than DZ twins, genetics played a larger role in second language acquisition than environment [7].

For our purposes, we will focus on SLA only. The results of the study pointed towards a genetic influence on SLA [7]. The MZ correlation for the L2 NC was .78 (.72, .82; 231), while the DZ was .48 (.40, .55; 373) [7]. The three numbers in the parentheses represent the low and high ranges of the 95% confidence interval, and the number of pairs included, respectively [7]. Overall, the heritability value for second language acquisition was 0.67 (.52, .80), far above that of shared environmental influence value 0.13 (.01, .27) [7].

It is clear, then, that heredity plays an important part in language. If heredity was strong in language acquisition, we would indeed expect the correlation for MZ twins, which share more genetic material, to be higher than the correlation for DZ twins, which share less genetic material, and are thus less “genetically bound.” A statistical analysis approach would reveal a p-value of 0.05 with a confidence interval of 95% [8, 9]. Because the intervals between the MZ correlation and DZ correlation and the heritability value and shared environmental influence value do not overlap, the results are likely statistically significant.

We have now seen that genetics plays a strong role in language development and acquisition. We will now investigate the effects of certain genetic conditions on language acquisition.

Effects of Certain Genetic Conditions on Language Acquisition

In a study by Ping C. Mamiya, Todd L. Richards, Bradley P. Coe, Evan E. Eichler, and Patricia K. Kuhl conducted on Chinese students learning English at the University of Washington, participants were enrolled in a language immersion program, and the white matter in their brains were analyzed throughout and after the program [5]. The study used specific DTI indices, namely fractional anisotropy (FA) and radial diffusivity (RD) values, as markers of brain activity and change due to language learning/development [5]. According to TA Keller and MA Just (2009) and D. Gebauer, et al. (2012), children with higher FA values and lower RD values were more proficient readers [5]. Diffusion tensor imaging (DTI) shows the state of the brain and white matter in response to foreign language acquisition [5]. The study found that COMT gene expression was correlated with FA and RD values in the superior longitudinal fasciculus, or SLF, during the immersion program [5]. The SLF is a bundle of fibers that connects the frontal lobe and ipsilateral hemisphere; it is part of the longitudinal association fiber system and plays a role in language [10]. Specifically, there are three variations of the COMT gene, as shown in Table 1 below.

Val/Val Amino acid valine is present in the protein coded for by both alleles of the gene.

Val/Met Amino acid valine is present in the protein coded for by one allele, while methionine is present in the protein coded for by the other allele.

Met/Met Amino acid methionine is present in the protein coded for by both alleles of the gene.

Source: https://www.pnas.org/doi/full/10.1073/pnas.1606602113

TABLE 1: Three Variations in the COMT Gene

The study found that while the Val/Val and Val/Met groups saw a significant RD value decrease as the number of days spent in the immersion program increased, such a significant decrease did not occur in the Met/Met group [5]. In addition, the study found that FA values increased more markedly in the Val/Val and Val/Met groups than the Met/Met group during the immersion program [5]. In other words, the study found that increased COMT activity (in the Val/Val and Val/Met groups) led to better language acquisition (indicated by lower RD values and higher FA values) throughout the program [5]. The study further postulated that increased FA may be associated with increased brain myelination, more axonal branching and growth, among other effects [5]. Both of these effects in particular clearly have positive effects for language development (myelination, for example, helps optimize transport of information).

Besides COMT, a variety of other genes, many of which control dopamine receptors in the dopaminergic system, have also been implicated in language learning. Studies by Lane, et al. (2008) and Rybakowski, et al. (2005), for example, have found that the A-48G polymorphism (DbSNP# rs4532) of the DRD1 gene, associated with allele A, increases binding and thus strengthens executive function and inhibitory control [11]. Executive function is needed in understanding language, expressing language to communicate, and interacting socially with others, also known as pragmatic language [12]. Meanwhile, Klein, et al. (2007) and Jocham, et al. (2009) found that the A1 allele in the Taq1A polymorphism (DbSNP# rs1800497) leads to reduced probabilistic learning abilities due to impairing DRD2 receptor density and dopamine binding to the receptor it codes for [11]. Additionally, studies by Rodriguez-Jimenez, et al., (2006), Frank, et al. (2009), Frank, et al., (2007), M. Hirvonen, et al., (2004), and J. Hirvonen et al., (2005) have found that in the C957T polymorphism (DbSNP# rs6277) of the DRD2 gene, the T allele increases binding, leading to strengthening of reward learning and executive functions [11]. Clearly, as we have seen, the variations in various different genes have major implications for learning abilities, which would play a large role in SLA.

Some important definitions for the preceding paragraph are presented below for the reader’s convenience.

•Polymorphisms are defined as various forms or “versions” of a DNA sequence that appears in humans [13]. One person may have one specific polymorphism, while another person may have another [13].

•The “DbSNP#” refers to the ID of the polymorphism in the Single Nucleotide Polymorphism Database [14].

Lastly, we will also go over the effects of the FOXP2 gene on language learning. Interestingly, FOXP2 was previously thought by many to be the “grammar gene,” according to Pinker 1994; however, more recent studies have shown that it functions in vocal articulation rather than grammar, according to Corballis 2004 [15]. Furthermore, a more recent study by Peter et al. 2011 found that the FOXP2 gene is involved in non-word repetition, real word reading efficiency, and rapid oral reading, skills which would be integral for SLA and language development [15]. Corroborating this claim, another study has implicated a certain single nucleus polymorphism (variation) of the FOXP2 gene in congenital dyslexia (Wilke et al, 2012), suggesting that FOXP2 is required for normal language learning and development [15].

As we have seen through our various examples, genes play a heavy role in the proper development of language and SLA. However, we must make a caveat and also acknowledge the importance of environmental factors in language development. For example, the Critical Period Hypothesis states that there is a critical window of time in early childhood to develop a first language [16]. If this window is missed due to lack of social interaction and isolation, it will become very difficult for the child to learn human language “to a native proficiency” [16].

Potential Variance for Language Acquisition Abilities across Various Populations

Given that we established much of language learning is hereditary, it would also be natural to question whether language acquisition abilities differ between various ethnic and racial groups, given that various ethnic and racial groups have differing genetic traits. One study established the differences between various groups. This study, carried out by Meg A. Palmatier, A. Min Kang, and Kenneth K. Kidd, was conducted with a sample size of 1314 people, and utilized Polymerase Chain Reaction, the NlaIII restriction enzyme, and gel electrophoresis [17]. It found that low levels of expression of the COMT gene were most common in Europeans and were less common in other ethnicities [17]. This is in line with the results of previous studies, which found a proportion of people with the COMT variant with decreased expression varied across various ethnic groups, with 18-27% of Caucaians having the decreased expression COMT variant, 1.5% of Asians (Filipino and Chinese) with the decreased variant, 7% of Blacks with the decreased variant, and 28% of Saami (a Norwegian ethnic group) with the decreased variant [17].

Given that we found earlier the correlation of COMT activity and language learning/development, we could postulate that, at least with respect to COMT’s role in language development only, Caucasian people of European descent may struggle more with language acquisition than other races. However, such a proposition does not claim to be true, as many other factors would affect language development, and the statement was also an extreme generalization.

Language is the Culmination of Environmental and Hereditary Factors

In this report, we reviewed the neurological and biological basis of human language, as well as certain key genes that are important in human language. We then investigated whether language learning and development is genetic or environmental. Finally, we examined how variations in certain genes could affect language development and how this could vary between populations.

While genetics, as we have seen, plays a large role in language, we cannot ignore the environmental factors that affect one’s abilities to acquire a second language. For example, it is well-known that the difficulty in learning a new language depends on one’s native language. An English speaker would have much more difficulty learning Mandarin Chinese or Japanese than Spanish or French, merely due to the fact that these languages are vastly different from English and are not close relatives, while Spanish and French both share many cognates with English (which draws on many Latin word roots) and are both Indo-European languages along with English. Similarly, it would be more difficult for a Mandarin Chinese speaker to read English than Japanese, due to the heavier differences and lack of cognates.

We hope that further research into the fascinating genetics of language acquisition can aid in the personalized teaching of foreign language and language therapy for disabled individuals.

References

1. Mathews, J. (2019, April 25). Perspective | Half of the world is bilingual. What's our problem? The Washington Post. Retrieved 2023, from https://www.washingtonpost.com/local/education/half-the-world-is-bilingual-whats-our-problem/2019/04/24/1c2b0cc2-6625-11e9-a1b6-b29b90efa879_story.html

2.Speech & Language | Memory and Aging Center.(n.d.). UCSF Memory and Aging Center. Retrieved 2023, from https://memory.ucsf.edu/symptoms/speechlanguage

3.FOXP2 gene.(2016, September 1). MedlinePlus. Retrieved 2023, from https://medlineplus.gov/genetics/gene/foxp2/

4.COMT gene.(2007, September 1). MedlinePlus. Retrieved 2023, from https://medlineplus.gov/genetics/gene/comt/

5.Mamiya, P. C., Richards, T. L., Coe, B. P., Eichler, E. E., & Kuhl, P. K. (2016).Brain white matter structureand COMT gene are linked to second-language learning in adults. Proceedings of the National Academy of Sciences, 113(26),7249–7254.https://doi.org/10.1073/pnas.1606602113

6.Genes and the environment equally affect language-related brain activity. (2016,December 29). ScienceDaily. Retrieved 2023, from https://www.sciencedaily.com/releases/2016/12/161229113423.htm#

7.Dale, P. S., Harlaar, N., Haworth, C. M. A., & Plomin, R. (2010). Two by two: A Twin Study of Second-LanguageAcquisition. Psychological Science, 21(5), 635–640. https://doi.org/10.1177/0956797610368060

8.What is a z-score? What is a p-value? ArcGIS Pro | Documentation.(n.d.). ArcGIS Pro Resources | Tutorials, Documentation,Videos & More. Retrieved 2023, from https://pro.arcgis.com/en/pro-app/latest/tool-reference/spatial-statistics/what-is-a-z-score-what-is-a-p-value.htm

9.Scott, G. (n.d.). What Is a Confidence Interval and How Do You Calculate It? Investopedia. Retrieved 2023,from https://www.investopedia.com/terms/c/confidenceinterval.asp

10.Janelle, F., Iorio-Morin, C., D’amour, S., & Fortin, D. (2022). Superior Longitudinal Fasciculus: A review of the anatomical descriptions with functional correlates. Frontiers in Neurology, 13. https://doi.org/10.3389/fneur.2022.794618

11.Wong, P. C. M., Morgan-Short, K., Ettlinger, M., & Zheng, J. (2012).Linking neurogenetics and individual differences in language learning: The dopamine hypothesis. Cortex, 48(9), 1091

1102. https://doi.org/10.1016/j.cortex.2012.03.017

12.Executive Function Skills & Language.(2018, July 24). INTEGRATED CHILDREN'S THERAPY. Retrieved 2023, from https://integratedchildrens.com/executive-function-skills-language/

13.Polymorphism.(2023,June 2). National Human Genome Research Institute. Retrieved 2023, from https://www.genome.gov/genetics-glossary/Polymorphism

14.dbSNP. (n.d.). Wikipedia.Retrieved 2023, from https://en.wikipedia.org/wiki/DbSNP

15.Vicario, C. M. (2013). FOXP2 gene and language development: The molecular substrateof the gestural-origin theory of speech? Frontiers in Behavioral Neuroscience, 7. https://doi.org/10.3389/fnbeh.2013.00099

16.Critical Period: Definition, Hypothesis, Examples. (n.d.). StudySmarter. Retrieved 2023, from https://www.studysmarter.us/explanations/english/languageacquisition/critical-period/

Palmatier, M. A., Kang, A. M., & Kidd, K. K. (1999).Global variation in the frequencies of functionally different catechol-O-methyltransferasealleles. Biological Psychiatry, 46(4), 557–567.https://doi.org/10.1016/s0006-3223(99)00098-0

Sleep.

Author:JamesL.

Edit:RyanMin

Facedwith increasinglymore rigorousactivitiesin academics,sports,and socialobligations,the averagehighschool studentsacrificesand disruptsoneessential biologicalrhythmto compensatefortime. Sleep.

Ithasbeenarelevant discussioninthe Californiaeducation system,exploringhow sleepcanbeimproved forhighschool students.Recently, thedistricthas experimentedwitha new“late-start” schedule,pushing backschoolstarttimes byonehour.So,what issleepandwhat makesitsorelevant andessential?

Sleepaccountsfor approximatelyathird ofthe24-hourcycle;it determinesthequality ofbasicfunctions throughouttheday andisasessentialto survivalasfoodand water.Itactsasa maintenancesystemin thebrain,clearingup unwanted,built-up proteinswith cerebrospinalfluid,a clearbodyfluidthat surroundsthebrain andspinalcord. Duringsleep,neurons (braincells)establisha strongerconnection, fortifyingmemories foreasierretrieval.

Theamalgamationof several neuroanatomical structureswithinthe brainworkstogether asamultifactorial process;severalbrain structuresaffectsleep andcanaffectcertain sleepdisorders.For example,the hypothalamusisa “peanut-sized” structuredeepwithin thebrainthatactsasa controlcenter affectingsleeparousal. Withinthe hypothalamusisa massofthousandsof cells,the suprachiasmatic nucleus(SCN),which receivesinformation aboutlightexposure. Thisinformationis theninterpretedto determineandcontrol thebehaviorrhythm ofsleep.Individuals withdamagetothe SCNmayhavean inconsistentsleep schedule,unableto matchtheircircadian rhythmwiththelightdarkcycle.

Sleepcanalsobe observedatasmaller scalebyexploringthe rolesofgenesand neurotransmitters. Accordingtothe DivisionofSleep MedicineatHarvard, “genesinfluencehow fastorslowour internalclockruns” (Chang).Itcanalso playasignificantrole inhowmuchsleepis needed,controlling theexcitabilityof neurons.Current knowngenesarePer, tim,andCrygenes, whichaffectthe circadianrhythmand timingofsleep. Overallresearch revealsthat, interestinglyenough, sleeppatternscanbe inherited.

Asurveyof1600 adolescentsinthe UnitedStatesbetween ages13and18 revealedthatteens wereaveraging7.4 hoursofsleepper night;theNational InstituteofHealth recommendsan averageof9.5hours. However,thereare remediestosleep disordersthatcanbe

implementedintodaily routinestohelpimprove thequalityandquantity ofsleep.Research suggeststhatacold sleepingenvironment (65degreesF)andmild exposuretolight improvedeepsleep experience,allowingfor abetter-restedbody.

Sleepisprecariousinthe circumstanceofahigh schooler.While academic,physical,and extracurricularactivities areimportantduring thisstageofastudent’s academiccareer,itisalso importanttotonedown andvaluewhatone’s bodysodesperately needs.Ifyoufeelyour eyesclosing,keepthem closed,andsuccumbto sleep it’simportant.

Figure1:thesuprachiasmaticnucleus(SCN)ofthe hypothalamus. Involvedwithreceivinginformation aboutlightexposure,controllingtheregulationofsleep. Imagecreditto:neuroscientificallychallenged.com

TheMechanismsoftheCarnot Battery—anditsAdvantages

Author:ChetT.

Edit:JamesL.

Abstract

Decarbonizationisnotplausiblewithonlyrenewableenergyproductiontechnologieslike solar,wind,andhydroelectricity;itlargelydependsonenergystorage.Solarandwind energysourcesareonlyutilizedwhenenergyislowindemand,contrastingtocoalandgas, whichareoftenusedinhighdemandbecauseoftheirabilitytoswiftlyconvertinto electricity.Coalandgashavethesuperiorabilitytobeefficientlystored,capableofbeing usedattimesofhighdemand.Inordertoincreasethereliabilityofrenewableenergy sources,oneneedstobeabletostorethem.Inthisarticle,weconsiderCarnotbatteriesasa contenderforuseasmajorenergyandpowersupplies.Wewillbriefthemechanismsofthe Carnotbatteryanditsabilitytostoreenergybyconvertingelectricitytomechanicalenergy toheat.WewilldetailthereverseCarnotcycleandtheuseofheatexchangersinsucha sophisticatedsystem.Analyzingtheproductionefficienciesofdifferentenergystorage systems,Carnotbatteriesprovedtohavehighenergydensitiesandroundtripefficiencies. RisingawarenessandspreadingknowledgeofCarnotbatterieswouldgainsupportfrom manycountries,people,andgroupssothatmoreofthesebatteriescanbeimplementedin Gridsystemsaroundtheworld.

Introduction

Withtheincreasingproblemswithclimatechange,mostpeoplebelievethatusing renewableenergysourceslikesolarandwindenergywouldsolvetheentireproblem,yetthatisnotthe fullpicture.Thoughcommercialoildrillingbeganaroundthe1850s,morethanhalfofourenergystill comesfromfossilfuels.Decarbonization,however,isfacedwithagreatchallenge,basedonalternative fuelsourceslikesolarandwind,whichcanbeunreliableduetofluctuationsintheamountofenergy producedduringtimesoftheday.Afifthoftheworld’senergycomesfromrenewablesources: geothermal,hydro,wind,andsolar.Thesesourcesalsodonotproduceenoughenergyintimesofhigh demand.Renewableenergyissimplynotefficientandreliableenough.Itisalsonotstorage-effective; solarandwindenergycannotbestored,unlikecoalorgas.Thestorageofthesesourcesissignificantas theythencanbereadilyavailabletoconsumersandanytime[1].Manypowerplantsuselargelithiumionbatteriestostoretheenergygeneratedtosupplytheenergytohomesandbuildingslater.However, thesebatteriesmaydegradetheenvironmentandarealsolessefficientinretrievingstoredenergy. About30-90%oftheenergyislost[2].Electricityisdifficulttostoreasitconstantlyconvertsitselfto heatthatdissipatesintothesurroundings.

Someideasbehindinnovationstosolvetheproblemofenergystoragearecompressedair, pumpedhydroelectricity,flywheel,batteries,andthemostpromising:thermalenergystorage [5].Thermalenergystorage(TES)iswhenamaterialobtainsenergyfromanincreasein temperatureorlosesenergyfromadecreaseintemperature.Thisenergygainedbythematerial canthenbeutilizedtogenerateelectricity.TESsystemshaveincreasinglybecomepopularbased onitsefficiencyofretrievingstoredenergy,andtheyarecost-effectivecomparedtootherstorage systems.OngoingprojectsliketheENDURINGprojectareimprovingthereliabilityofthermal energystoragesystemsandtheircost-effectiveness.AnexampleofaTESsystemistheCarnot battery,andmanyongoingprojectsaretestingtheimplementationoftheCarnotbatteryinto gridsystems.CarnotandReverseCarnotCyclesarekeyprinciplesthatgovernthefunctionof CarnotBatteries.

CarnotandReverseCarnotCycles

TheSecondLawofThermodynamicsisbasedonenergyconservationandmorespecifically, statesthatheatflowsfromahotterobjectorareatoacoolerone.TheCarnotCycleisalsoanothertype ofenergyconversionbutconvertsheattowork.Steamenginesareheatenginesthatunderliethesame conceptsastheCarnotcycle,whichutilizestheforceduetosteampressureformechanicalwork.The pressurethatincreasesduetotemperatureisresponsibleforthework.TheCarnotBatteriesoperate withthereverseCarnotCycle,whichisquiteliterallytheCarnotcyclebutinreverse(asshownin diagramslater).TheCarnotCyclehastworeservoirs,onethatinitiallystartsoffatahighertemperature comparedtotheotherreservoir,fromwhichthegasatthehighertemperaturemovestowardsthe lower,simultaneouslyprovidingwork.ThereverseCarnotCyclealsohastworeservoirsbuttransfers heatfromacolderlocationtoawarmerone.Thoughonemightthinkthisexchangedisobeysthe secondlawofthermodynamics,theprocessofthecyclefullyobeysit.Inordertocomprehendthe reverseCarnotCycleinCarnotBatteries,let'sunderstandthebasicsofthetwocyclesandthencompare thetwo.

ProcessesintheCarnotCycle:

TheCarnotcycleiscomposedof4stages:Isothermalexpansion,Isentropicexpansion, Isothermalcompressions,andAdiabaticcompressioninthatorder[4].

IsothermalExpansion:thegasinthecontainer becomesthermallyincontactwiththehot reservoir,increasingthegas'stemperature,and simultaneouslymovingthepistonupward.The gasshowninthefiguretotheleftisnotin contactwiththecoldreservoir.

IsentropicExpansion:Oncethegasisnotin contactwiththehotorcoldreservoirs,the pistonstillexpandsbecauseofthehot existinggas.Thisprocessisknownas adiabaticasthesystem(ofthegas)isnot gainingorlosingheat.

IsothermalCompression:Thegas beingincontactwiththecold reservoirtransformsitsenergyintoit becauseofthesecondlawof thermodynamicsasthehotterair flowstowardsthecolder.The resultingtransfermovesthepiston down,decreasingthetemperature andpressure.

Adiabaticcompression-Similarto isentropicexpansionwiththegasnot beingincontactwitheachreservoir, thepistonwouldstillmovedownas thesurroundinghotairpushesthe pistondown.Thegasafterthe compressionwouldbecomesimilar tothegasbeforeisothermal expansion.

ProcessintheReverseCarnotCycle:

ThereverseCarnotCycleiswhenheatismovedfromacolderlocationtoahotterone. Removingheatfromacoolerlocationisdonewithheatpumps.Howtheheatpumpsoperatewillbe describedalongwiththestepsofthereverseCarnotCycle.ThereverseCarnotCyclehasanother commonnamewhichisthevapor-compressionrefrigerationcycle.Asthenamesuggests,itismost commonlyusedinrefrigeratorsandairconditioners.Thefigurebelowrepresentsavapor-compression cyclethatisanalogoustothereverseCarnotCycle.Thevapor-compressioncyclehasarefrigerant whichisaliquidthatundergoesmanyphasetransitions.Thecycleinvolvesacompressor,condenser, expansionvalve,andanevaporator[5].

1.Therefrigerantbeginsasavaporthatentersthecompressor,increasingitstemperatureandpressure. Thecompressor,drivenbyelectricity,istheexternalworkthatisappliedtothegas.

2.Thehigh-temperaturevaporgoesintothecoilsandtubingsofthecondensertobeconvertedintoa liquid.Acondenserisanexampleofaheatexchangerthatreliesonasecondarysource(likestoredfluids) toreduceandcondensatethevapor[3].Thesecondarysourcehasalowertemperaturethanthevapor, allowingheattotransferfromthevaportothesource.Theresultingliquidhasarelativelylow temperaturetothatofvapor,yetstillhasthesamepressure,whichiswheretheexpansionvalvecomesin.

3.Theexpansionvalvereducesthepressuresignificantly,simultaneouslydecreasingthetemperatureby expandingtheliquid.

4.Passingnowthroughtheevaporator,afanblowsinairfromtheenvironment(outsidethe refrigerator/cycle)thatiswarmerthantheliquid,evaporatingtheliquid,andtransformingitintovapor. Thewarmairthenbecomescoolerasthecooltemperatureshiftsfromliquidtovapor.Thiscoldairis usedbyrefrigerators.[6]Theliquidisthenreusedbythecondenser,repeatingtheprocess.

ImageCredit:https://processsolutions.com

ComparingtheCarnotCycleandtheReverseCarnotCycle:

CarnotCycle

ReverseCarnotCycle

ThegraphontheleftfollowstheCarnotCyclewhilethegraphontherightfollowsthe reverseCarnotCycle.Bothofthesegraphsrepresentthephaseshiftsorchangesthatoccurinthe gasthatmovesthroughthetwocycles.InorderfortheReverseCarnotCyclethatstartsatposition 1tomovetoposition2,whichhasagreaterpressure,externalworkmustbeat“work”.Electricity operatesthecompressorthatcompressesthegasatposition1movingittoposition2.Contrasting fromtheCarnotCycle,position1startsoffathighpressurewithlowvolume,emphasizinga greatertemperature.Thearrowsinbothgraphsmoveindifferentdirections,andthisisthemain differencebetweenthetwocycles.ThereverseCarnotcyclerequiresexternalworkandsourcesto increasetheinitiallowtemperature.Thecondenserandevaporatorfunctionasheatpumpsinthe system.Heatpumpsareresponsibleformakingthecoldgascolderandthewarmgaswarmerinthe system.Inthevapor-compressionrefrigerationcyclefigure,asexplained,thecondenserand evaporatorrelyonasecondarysourcethatisgenerallycolderthanthecoldsourceorwarmerthan thewarmsource.Asaresult,heattransfersoutofthegasandintothesecondarysources.Thus, makingcoldgascolderandwarmgaswarmer.Theinteractionsbetweenthegasandtheexternal sourcesarehowthereverseCarnotCyclestillobeysthesecondlawofthermodynamics.Relating externalforcesandobjectsinthefiguretotheReverseCarnotgraph;Isentropic Compression→functionofthecompressor,IsothermalCompression→functionofcondenser, IsentropicExpansion→functionofExpansionvalve,isothermalexpansion→functionofthe evaporator.RecognizingimportantaspectsinthereverseCarnotCycle,wecannowbeableto understandhowCarnotBatteryoperates.

TheCarnotBatterySystem

Carnotbatteriesstoreenergythroughtheuseofthermalenergystorage systems(TES).Thesesystemsareoftenmaterialsthatareabletoremainathightemperatures forlongperiodsoftime.InCarnotbatteries,differentmaterialsforTESareused,butthe cheapest,mostefficient,andleastharmfultotheenvironmentismoltensalt.Moltensalt,or simplyliquidsalt,iskeptat288degreesCelsiusinaninsulatedstoragetank,whichcankeep thissaltataconstanttemperatureforaweek.

TheschemeofaCarnotbatterysystemisshownabove.TheP2Tstageisthecharge stagewhereelectricityisconvertedtoheatstoredinTES.TheT2Pstageisthedischargestage, whereheatisconvertedbacktoelectricity. TheCarnotbatterysystemutilizesthereverse Carnotcycle.IntheP2Tstage,orthechargingstage,theheatexchangersthatcorrespondto thereverseCarnotcyclearetheHotTESchargingandColdTESchargingshowninthefigure below.Carnotbatteriesareabletochargeanddischargebycreatingtemperaturegradients betweentheHotandColdreservoirs[7].

Imagecredit:https://www.dlr.de/tt/Portaldata/41/Resources/dokumente/tp/Carnot_Batteries_background_document-V2.pdf

ProcessofT2PStageBasedonthefigurebelow:

•Thechargingofthesystemstartswithexternalworkapplied tothesystemthatcompressesthegas(1-2).Thecompressed gasthenmovestowardstheexchangerreleasingitsheattothe hotthermalenergystorage.

•HotTESworkssimilarlytotheheatexchanger,asa secondarysourceisusedthatiscoolerthanthehotgas,andthe resultinggastransfersheattothesecondarysource.The secondarysourcethenstoresthisheat.Theproceedinggas decreasesintemperatureyetstillhasthesamepressure,which duetoanexpanderatpoints3-4reducesthetemperature further.ThisreductionintemperaturethenmovestoCold TEScharging,wherethecoldTESiswarmerthanthisgas.

•InthecoldTESchargingshowninthepicture,thecoldgasincreasesintemperatureasheatistaken awayfromthestorageandtransferredtothegassincethetemperatureofthegaswasmuchcoolerthan thatofthecoldTES.TheresultinggasafterColdTESchargingisfurtherheatedbytheheatertobringit backtonormalroomtemperaturetobereused.Thereusabilityofthegasisanotherbenefitofutilizing Carnotbatteries.

ProcessoftheT2Pstagebasedonthefigurebelow:

•Ratherthangasbeingused,molten-saltorliquidsaltisused inthisprocess.Thedischargebeginswiththetransferof moltensaltfromHotTEStoasteamgeneratorlocated betweenpoints2’-1’.Thisgeneratorhasaconventional turbineusedtoproduceenergyfromthesteam.

•Betweenpoints1’-4’,thefluidcoolsdownandbecomesa normaltemperaturesothatthecompressorbetweenpoints4’3’won’thavetoexertanyworkintothesystem.Theresulting fluidisthenusedtogetheatedupagainintheHotTES charging,makingitreusable.

WhyWeShouldUseCarnotBatteries

Othermainmethodstostoreelectricityarepumpedhydroelectricityandlithiumionbatteries.Manyofthesemethodsarealreadyimplementedaroundtheworld,andtheir efficienciesaretrackeddownbytheWorldEnergyCouncil.Thefigurebelowrepresentsthe productionofdifferentenergysystems[10].

Pumpedhydroelectriciswhenexcesselectricityisproducedbygeneratorsusedindams, sopumpsacquiresomeofthisenergytopumpwaterbacktothetopoftheriverordam. Lithium-ionbatteriesarethesamebatteriespresentinourphonesbutalotbiggerastheyare usedingridsystems.Comparingthemaxpoweringratinganddischargetimeinpumped hydroelectricity,lithium-ionbatteries,andpumpedhydrohavethegreatestpowerrating,but alsothegreatestdischargetime.Whilelithium-ionbatterieshavetheleastpowerratingof100 MW,theystillhavethefastestdischargetimeat1min-8hours.MoltenSaltTESisinthe middleofthetwostoragesystemswhencomparingthepowerratingsanddischargetimes.A significantbenefitofMoltensaltTESisthehighenergydensitiesandroundtripefficiencies. ThoughtheLi-ionbatterieshavegreatervaluesofhighenergydensitiesandroundtripefficiency comparedtoTES,Li-ionbatterieshaveagreatercostperMWhmakingthemexpensive.Inan articlebyIntertekcomparingthecostofstorageperMWh,LazardFinancialAdvisory comparedthesevaluesinmultiplestoragesystems.Itwasfoundthatpumpedhydrorequires $263/MWh,TESrequires$331/MWh,andli-ionbatteriesat$652/MWh[12].

MoltenSaltTEScanbeutilizedanywhereandinthegridsystemsdirectlyunlikepumped hydroelectricitywhichcanonlyworkindamsandnearrivers.MoltensaltTESalsocontains safermaterialthanthehazardouschemicalsinlithium-ionbatteries.Lithium-ionbatteries containtoxicelementscobalt,nickel,andmanganesewhichcancontaminatetheenvironment andwater.MoltenSaltTESareleastincost,highinefficiency,safefortheenvironment,andcan beaccessedanywheredirectlythroughgridsystems.Thus,TESisanongoingareaof developmentwheremanyexistingprojectsareworkingonimprovingTES.

CurrentProjectsonCarnotBatteries

TheInternationalEnergyAgency “workswithgovernmentsandindustry toshapeandsecureasustainableenergy futureforall”[8].Manyongoing projectsarestudyingmethodsto increaserenewableenergysources.

TheagencycreatedtheEnergyStorage Task36grouptoimplementand advanceCarnotbatteriesinGermany. TheobjectivesofTask36aretoidentify theapplicationsofthesebatteries,test andexaminetheminordertodevelop them,andaidinthemarketingofthe batteries.Thepicturebelowrevealshow Task36isplanningtouseCarnot batteriesingridenergysystems[9].

eries_background_document-V2.pdf

TheNationalRenewableEnergyLaboratory(NREL)is“transformingenergythrough research,development,commercialization,anddevelopmentofrenewableenergyandenergy efficiencytechnologies”[13].AnotherongoingprojectistheENDURINGprojectwhichuses silicasandinsteadofmoltensandtostoreheat.Thisformofenergystorageisinexpensiveat$2$4/kWhbecauseitusesparticleTESwhichrequireslessmaintenancecomparedtomoltensand. Anotherbenefitisthatitcanbebuiltanywherebasedonthematerialused.Theteamthatwas partofthisprojectwonmultiplefundsandawardsliketheSolarEnergyDivision2021FirstPlaceBestPaperAward.OtherresearchprogramsworktoimproveTESsystemsliketheE3 Initiative,GEBInitiative,andEnergyStorageGrandChallenge[16].Theseprogramsplanto improvethermalenergystoragesystemsbyhavingthefollowingtargets:

•<$15/kWh

•>80kWh/liter

•>10,000cycles

ImplementingCarnotBatteriesingridsystemsgloballywouldsignificantlyaidtheenvironment asrenewableenergysourcescanfeasiblybestored.

Imagecredit: https://www.dlr.de/tt/Portaldata/41/Resources/dokumente/tp/Carnot_Batt

Conclusion

Inthisarticle,wehavegoneoverthevariousprocesses,materials,andefficiencyoftheCarnot batteries.Weexaminedotherhigh-energy-densitystoragesystemsandcomparedthemwith Carnotbatteries.ThepurposeofCarnotbatteriesistoreducetheusageoffossilfuelsasanondemandenergysource.Otheralternativesources,suchassolarandwindenergy,haveprovento belessefficientthanCarnotbatteriesduetounpredictablefluctuationsthroughoutthedayand thuscannotbeusedason-demandenergysources.Carnotbatteriesstorerenewableenergy sourcessothattheycanbeharnessedason-demandsources.UtilizingCarnotbatteriesingrid systemscanmakeittrouble-freetoswitchbetweenenergysourcestotransporttothepowerand gridlines.Newtechnologiesinvolvingenergystoragetechnologiescantransformtheworld’s energysystem,significantlyreducingglobalwarming.

1.https://www.bbc.com/future/article/20170313-the-biggest-energy-challenges-facing-humanity

2.https://essentialenergyeveryday.com/solutions/renewableenergy/#:~:text=Solar%20and%20wind%20facilities%20use,to%20deliver%20on%2Ddemand%20po wer.

3.https://www.ucsusa.org/resources/how-electricity-grid-works

4.https://energsoft.com/blog/f/energy-storage-problems

5.https://www.epa.gov/energy/electricitystorage#:~:text=Batteries.,iron%20or%20other%20battery%20technologies.

6.https://www.gatesnotes.com/It-Is-Surprisingly-Hard-to-Store-Energy

7.https://en.wikipedia.org/wiki/Brayton_cycle#Reverse_Brayton_cycle

8.https://www.nuclear-power.com/nuclear-engineering/thermodynamics/thermodynamiccycles/heating-and-air-conditioning/reverse-brayton-cycle-brayton-refrigeration-cycle/

9.https://en.wikipedia.org/wiki/Carnot_cycle#math_Figure_1

10.https://processsolutions.com/how-does-a-compression-refrigeration-systemwork/#:~:text=The%20Vapor%20Compression%20Refrigeration%20Cycle&text=As%20the%20refr igerant%20circulates%20through,temperature%20of%20the%20conditioned%20space.

11.https://www.mecholic.com/2018/03/cop-reversed-carnot-cycle.html

12.https://www.sciencedirect.com/science/article/pii/S2352152X22017704

13.https://theconversation.com/how-heat-can-be-used-to-store-renewable-energy-130549

14.https://www.iea.org/about

15.https://www.eces-a36.org/index.php/about-annex-36/

16.https://celsiuscity.eu/thermal-energy-storage/