简介:Anewmethodwasdescribedforusingarecurrentneuralnetworkwithbiasunitstopredictcontactmapsinproteins.Themaininputstotheneuralnetworkincluderesiduespairwise,residueclassificationaccordingtohydrophobicity,polar,acidic,basicandsecondarystructureinformationandresidueseparationbetweentworesidues.Inourwork,adatasetwasusedwhichwascomposedof53globulinproteinsofknown3Dstructure.Anaveragepredictiveaccuracyof0.29wasobtained.Ourresultsdemonstratetheviabilityoftheapproachforpredictingcontactmaps.
简介:Mosquitoesareexceptionalintheirabilitytopierceintohumanskinwithanaturalultimatepainlessmicroneedle,namedfascicle.HerethestructureoftheAedesalbopictusmosquitofascicleisobtainedusingaScanningElectronMicroscope(SEM),andthewholeprocessofthefascicleinsertingintohumanskinisobservedusingahigh-speedvideoimagingtechnique.Directmeasurementsoftheinsertionforceformosquitofascicletopenetrateintohumanskinarereported.Resultsshowthatthemosquitousesaverylowforce(average18μN)topenetrateintotheskin.Thisforceisatleastthreeordersofmagnitudesmallerthanthereportedlowestinsertionforceforanartificialmicroneedlewithanultrasharptiptoinsertintothehumanskin.Inordertounderstandthepiercingmechanismofmosquitofascicletipintohumanmultilayerskintissue,anumericalsimulationisconductedtoanalyzetheinsertionprocessusinganonlinearfiniteelementmethod.Agoodagreementoccursbetweenthenumericalresultsandtheexperimentalmeasurements.
简介:Detectingtheboundariesofproteindomainsisanimportantandchallengingtaskinbothexperimentalandcomputationalstructuralbiology.Inthispaper,apromisingmethodfordetectingthedomainstructureofaproteinfromsequenceinformationaloneispresented.Themethodisbasedonanalyzingmultiplesequencealignmentsderivedfromadatabasesearch.Multiplemeasuresaredefinedtoquantifythedomaininformationcontentofeachpositionalongthesequence.Thentheyarecombinedintoasinglepredictorusingsupportvectormachine.Whatismoreimportant,thedomaindetectionisfirsttakenasanimbalanceddatalearningproblem.Anovelundersamplingmethodisproposedondistance-basedmaximalentropyinthefeaturespaceofSupportVectorMachine(SVM).Theoverallprecisionisabout80%.Simulationresultsdemonstratethatthemethodcanhelpnotonlyinpredictingthecomplete3Dstructureofaproteinbutalsointhemachinelearningsystemongeneralimbalanceddatasets.
简介:Nonverbalandnoncontactbehaviorsplayasignificantroleinallowingservicerobotstostructuretheirinteractionswithhumans.Inthispaper,anovelhuman-mimicmechanismofrobot’snavigationalskillswasproposedfordevelopingsociallyacceptableroboticetiquette.Basedonthesociologicalandphysiologicalconcernsofinterpersonalinteractionsinmovement,severalcriteriainnavigationwererepresentedbyconstraintsandincorporatedintoaunifiedprobabilisticcostgridforsafemotionplanningandcontrol,followedbyanemphasisonthepredictionofthehuman’smovementforadjustingtherobot’spre-collisionnavigationalstrategy.Thehumanmotionpredictionutilizesaclustering-basedalgorithmformodelinghumans’indoormotionpatternsaswellasthecombinationofthelong-termandshort-termtendencypredictionthattakesintoaccounttheuncertaintiesofbothvelocityandheadingdirection.Bothsimulationandreal-worldexperimentsverifiedtheeffectivenessandreliabilityofthemethodtoensurehuman’ssafetyandcomfortinnavigation.Astatisticalusertrialsstudywasalsogiventovalidatetheusers’favorableviewsofthehuman-friendlynavigationalbehavior.
简介:ThespinesofpencilandlanceurchinsHeterocentrotusmammillatusandPhyllacanthusimperialiswerestudiedasamodeloflight-weightmaterialwithhighimpactresistance.Thecomplexandvariableskeletonconstruction("stereom")ofbodyandspinesofseaurchinsconsistsofhighlyporousMg-bearingcalciumcarbonate.Thisbasicallybrittlematerialwithpronouncedsingle-crystalcleavagedoesnotfracturebyspontaneouscatastrophicdevicefailurebutbygracefulfailureovertherangeoftensofmillimeterofbulkcompressioninstead.Thiswasobservedinbulkcompressiontestsandbluntindentationexperimentsonregular,infiltratedandlatexcoatedseaurchinspinesegments.MicrostructuralcharacterizationwascarriedoutusingX-raycomputertomography,opticalandscanningelectronmicroscopy.Thebehaviorisinterpretedtoresultfromthehierarchicstructureofseaurchinspinesfromthernacroscaledowntothenanoscale.Guidelinesderivedfromthisstudyseeceramicswithlayeredporosityasapossiblebiomimeticconstructionforappropriateapplications.
简介:Seaurchinspineswerechosenasamodelsystemforbiomimeticceramicsobtainedusingstarch-blendedslipcasting.Porousaluminaceramicswithcap-shapedlayerswithdifferentalternatingporositieswerefoundtohavesuperiorfracturebehaviorunderbulkcompressioncomparedtoceramicswithuniformporosity.Theyfailinacascadingmanner,absorbinghighamountsofenergyduringextendedcompressionpaths.TheporosityvariationinanotherwisesinglephasematerialmimicksthearchitecturalmicrostructuredesignofseaurchinspinesofHeterocentrotusmammillatus,whicharepromisingmodelmaterialsforimpactprotection.