RESEARCHERSfromthe MoscowInstitute
of Physicsand Technology(MIPT)and the
LebedevPhysicalInstituteof the Russian
Academyof Sciences havedesignedand
tested a prototypecathodoluminescent
lampfor generallightingthatcouldun-
leasha lamprevolution.The newlamp,
whichrelieson the phenomenonoffield
emission,is morereliable,durableand
luminous than its analoguesavailable
worldwide.The developmenthas beenre-
portedin the “Journal of VacuumScience
& TechnologyB”.
WhileLEDlampshavebecomecom-
monplace,theyare not the onlycleanand
power-savingalternativeto incandescent
lamps.Cathodoluminescentlampsrely on
the sameprincipleas old TVs,usingcath-
ode-raytubes.A negatively chargedelec-
trode,or cathode,at one end of a vacuum
tubeservesas an electrongun.A potentialdifferenceof up to 10 kilovolts
acceleratesthe emittedelectronstowardsaflat positivelycharged
phosphor-coatedelectrode—theanode—at the oppositeend of the tube.
This electronbombardmentresultsin light.Suchlampscan emitlightat
any wavelength,fromthe red to ultraviolet(UV),dependingon which
fluorescentmaterialis used.
CathodoluminescentUV lightbulbscontainno mercuryandare
generallycleanerin serviceand upondisposal.“Cathodoluminescent
lampscouldbe usedin medicine,like for operating roomdecontamina-
tion,UV irradiationof throatandtonsils,anddentalfillingcuring,”
commentedMikhailDanilkinof the LebedevPhysicalInstitute.Another
importantadvantageof the new lampoverLEDsandfluorescentbulbsis
that it doesnot rely on so-calledcriticalraw materials,whichinclude
gallium,indiumand somerare-earthelements,whosesupplyis limited
and irreplaceable in health,defence,aerospaceand otherkey industries.
However,designingan efficient,long-lastingandtechnologically
advancedcathodethatcouldbemass-producedandsoldatanaffordable
pricehas provedchallenging.Whilethereare ongoingeffortsin Japan
and the U.S.,this Russianstudymarksthefirst successfulattemptat
this.“Ourfield emissioncathodeis madeof ordinarycarbon,” said
ProfessorEvgeniiSheshinof the MIPT,who led the researchteam.“But
thiscarbonisnot usedmerelyas achemicalbutratheras astructure.We
founda way to fashiona structurefromcarbonfibresthat is resistantto
ion bombardment, outputsa highemissioncurrentand is affordable in
production.”The MIPTresearchgrouphas alsodevelopeda compact
powersourcefor its cathodoluminescentlamp.Thesourceisfitted
aroundthe glasslightbulbwith almostno effecton its size.The luminous
poweris up to 250 lumens,aboutthe outputof a 25-wattincandescent
lamp,but the powerconsumption is only 5.5 watts.The technical charac-
teristicsand prototypetest datareportedin the papersuggestthatif
mass-produced,thesenew bulbscouldcompetewithLEDlamps.AnalternativetoLEDlamps
THEGovernmentof Indiabanned“Diclofenac
and its formulations for veterinaryuse”in
July 2008 witha viewto conservingvultures
and, in July 2015,alloweduse of the drugas a
single-doseinjectionfor humansonly.Ac-
cordingto wildlifeveterinarians,the key
causeof vulturedeathsis food poisoning.The
birdswerefeedingon deadanimalsthat had
beenadministeredthe non-steroidalanti-in-
flammatory drug (NSAID) diclofenac as
painkiller.Whenthe gypsspeciesfed on
thesecarcasses,theyfacedacuterenalfail-
ure and died.
Vulturesare amongthe top predators
and are enlistedin the criticallyendangered
categoryin the IUCNRed List of Threatened
Species.In a relatednewdevelopment,the
Governmentof Indiais alsolikelyto ban the
analogueNSAIDaceclofenacfor veterinary
use,givenits potentialto kill vultures,ac-
cordingto K.K.Aggarwal,whoreportedthis
developmenton the medicalnewswebsite
emedinexus.com. According to him, the
Drugs Consultative
Committee of the
Union Health Min-
istryhad considered
this issuein its 56th
meeting held on
June1 in NewDelhi.
A researchnote
submittedby Vibhu
Prakash, Principal
Scientistand Deputy
Director, Vulture
Conservation
Breeding Centre
(VCBC),Panchkula, Haryana,on “Metabol-
ism of Aceclofenacin cattleto Vulture-killing
Diclofenac”,hadapparentlyservedas the
basisfor this move.The VCBChad requested
prohibitionon veterinaryuse of aceclofenac
as well.In a 2016researchstudy,TobyHeath
Calligan(of the RoyalSocietyfor Protection
of Birds)and othersfoundthat nearlyall of
the aceclofenacadministeredto cattlein the
recommendeddosewasveryrapidlymeta-
bolisedinto diclofenac.The studypointedout
thatat least 12 other NSAIDs, besides
diclofenac,wereavailable for veterinaryuse
in SouthAsia,and aceclofenacwasone of
them. StoriescompiledbyR.Ramachandran
HEALTH/ REPRODUCTION/ CONSERVATION / PHYSICS
Painkillerbantosave
vultureslikely
Cathodoluminescentlamp:
(1) cathodemodulatorunit,
(2) cathode,(3) modulator,
(4) emitted electrons,
(5) phosphor, (6) aluminum
mirrorservingas anode,
(7) anode output, (8) glass
vacuumtube. EVGENIISHESHINETAL./JOURNALOFVACUUMSCIENCE&TECHNOLOGYBWHITE-RUMPED
VULTURES.
REUTERS