简介:Wehavecarriedoutanexperimentalstudyofliquiddropimpactonsuperhydrophobicsubstratescoveredbyacarpetofchemicallycoatednano-wires.Themicro-structureofthesurfaceissimilartosomebiologicalones(Lotusleafforexample).Inthissituationthecontactanglecanthenbeconsideredasequalto180degrees,withnohysteresis.Duetoitsinitialinertia,thedropexperiencesaflatteningphaseafterithitsthesurface,takingtheshapeofapancake.Onceitreachesitsmaximallateralextension,thedropbeginstoretractandbouncesback.Wehaveextractedthelateralextensionofthedrop,andweproposeamodelthatexplainsthetrend.Wefindalimitinitialvelocitybeyondwhichthedropprotrudesintothenano-wirecarpet.Wediscusstherelevanceofpracticalissuesintermsofself-cleaningsurfacesorspray-cooling.
简介:Twenty-ninespeciesofbutterflieswerecollectedforobservationanddeterminationofthewingsurfacesusingaScanningElectronMicroscope(SEM).Butterflywingsurfacedisplaysstructuralanisotropisminmicro-,submicro-andnano-scales.Thescalesonbutterflywingsurfacearrangelikeoverlappingrooftiles.Therearesubmicrometricverticalgibbosities,horizontallinks,andnano-protuberancesonthescales.First-incline-then-dripmethodandfirst-drip-then-inclinemethodwereusedtomeasuretheSlidingAngle(SA)ofdropletonbutterflywingsurfacebyanopticalContactAngle(CA)measuringsystem.Relativelysmallerslidinganglesindicatethatthebutterflywingsurfacehasfineself-cleaningproperty.SignificantlydifferentSAsinvariousdirectionsindicatetheanisotropicself-cleaningpropertyofbutterflywingsurface.TheSAsonthebutterflywingsurfacewithoutscalesareremarkablylargerthanthosewithscales,whichprovesthecrucialroleofscalesindeterminingtheself-cleaningproperty.Butterflywingsurfaceisatemplatefordesignandfabricationofbiomimeticmaterialsandself-cleaningsubstrates.Thisworkmayofferinsightsintohowtodesigndirectionalself-cleaningcoatingsandanisotropicwettingsurface.
简介:Thecontactanglesofdistilledwaterandmethanolsolutiononthewingsofbutterfliesweredeterminedbyavisualcontactanglemeasuringsystem.Thescalestructuresofthewingswereobservedusingscanningelectronmicroscopy,Theinfluenceofthescalemicro-andultra-structureonthewettabilitywasinvestigated.Resultsshowthatthecontactangleofdistilledwateronthewingsurfacesvariesfrom134.0°to159.2°.Highhydrophobicityisfoundinsixspecieswithcontactanglesgreaterthan150°.Thewingsurfacesofsomespeciesarenotonlyhydrophobicbutalsoresistthewettingbymethanolsolutionwith55%concentration.OnlytwospeciesinParnassiuscannotresistthewettingbecausethemicro-structure(spindle-likeshape)andultra-structure(pinnule-likeshape)ofthewingscalesareremarkablydifferentfromthatofotherspecies.Theconcentrationofmethanolsolutionfortheoccurrenceofspreading/wettingonthewingsurfacesofdifferentspeciesvariesfrom70%to95%.Afterwettingbymethanolsolutionfor10min,thedistilledwatercontactangleonthewingsurfaceincreasesby0.8°-2.1°,showingthepromotionofcapacityagainstwettingbydistilledwater.
简介:Internationalnon-governmentalorganizationswereamongthefirstinternationalactorsthatrespondedtotheemergenceofAIDScrisisinChina.Since1994,thenumberofinternationalnon-governmentalorganizationsandcharitablefoundationsworkinginAIDSrelatedissueareasinChinahasgrownsteadilyandsubstantially.Despitetheirorganizationaldifferences,mostofthesenon-governmentalactorspresentthecharacteristicsofindependentmission,localizedpracticeanddiverseworkingfocus.Eventhoughtheyareconstrainedbyfinancialandotherfactorscomparedwithmultilateralandbilateralofficialassistanceagencies,theyhavestillplayedauniqueroleinfightingagainstAIDSinChinaastechnicalexperts,publiceducators,andcivilsocietysupporters.
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简介:在病原体识别的像使用费的受体(TLR)的角色在最近的年里是快速地先进的。然而,进在非传染的织物损害的TLR的功能的调查刚开始了。以前,我们和其它表明了那碎裂的hyaluronan(哈)在织物损害期间积累。CD44被要求在织物损害期间清除HA,并且损害了清理哈在不停的发炎的结果。另外,碎裂哈在损害地点由煽动性的房间刺激煽动性的基因的表示。最近,我们识别了那哈碎片要求TLR2和TLR4刺激老鼠巨噬细胞生产煽动性的chemokines和cytokines。在一个非传染的肺损害模型,在TLR2和TLR4缺乏的老鼠显示出煽动性的房间的损害transepithelial迁居,增加的织物损害,提高的肺上皮的房间apoptosis,和减少的幸存。在高分子的质量的表示上的肺上皮的房间哈对尖锐的肺损害和apoptosis的保护的老鼠,部分地通过NF-kappaB的TLR依赖的基础激活。在TLR2和TLR4的夸大的损害缺乏的老鼠看起来由于上皮的房间上的损害HA-TLR相互作用。这些研究识别那个主机矩阵部件哈并且TLR相互作用提供开始煽动性的回答的信号,维持上皮的房间完整,并且支持从尖锐的肺损害的恢复。房间研究(2006)16:693-701。做i:10.1038/sj.cr.7310085;出版联机2006年8月8日。
简介:Domaindatabaseisessentialfordomainpropertyresearch.Eliminatingredundantinformationindatabasequeryisveryimportantfordatabasequality.Herewereportthemanualconstructionofanon-redundanthumanSH2domaindatabase.Thereare119humanSH2domainsin110SH2-containingproteins.HumanSH2swerealignedwithClustalX,andahomologoustreewasgenerated.Inthistree,proteinswithsimilarknownfunctionwereclassifiedintothesamegroup.Someproteinsinthesamegrouphavebeenreportedtohavesimilarbindingmotifsexperimentally.Thetreemightprovidecluesaboutpossiblefunctionsofhypotheticalproteinsforfurtherexperimentalverification.
简介:Thepitching-downflappingisanewtypeofbionicflapping,whichwasinventedbytheauthorbasedonpreviousstudiesontheaerodynamicmechanismsoffruitfly(pitching-up)flapping.ThemotivationofthisinventionistoimprovetheaerodynamiccharacteristicsofflappingMicroAirVehicles(MAVs).Inthispaperthepitching-downflappingisbrieflyintroduced.Themajorworksinclude:(1)Computingthepowerrequirementsofpitching-downflappinginthreemodes(advanced,symmetrical,delayed),whichwerecomparedwiththoseofpitching-upflapping;(2)Investigatingtheeffectsoftranslationalaccelerationtime,Δτ_t,androtationaltime,Δτ_r,attheendofastroke,andtheangleofattack,α,inthemiddleofastrokeontheaerodynamiccharacteristicsinsymmetricalmode;(3)Investigatingtheeffectofcamberonpitching-downflapping.Fromtheaboveworks,conclusionscanbedrawnthat:(1)Comparedwiththepitching-upflapping,thepitching-downflappingcangreatlyreducethetime-averagedpowerrequirements;(2)TheincreaseinΔτtandthedecreaseinΔτ_rcanincreaseboththeliftanddragcoefficients,butthetime-averagedratiooflifttodragchangesalittle.Andαhassignificanteffectontheaerodynamiccharacteristicsofthepitching-downflapping;(3)Thepositivecambercaneffectivelyincreasetheliftcoefficientandtheratiooflifttodrag.
简介:PBONDisawebserverthatpredictstheconformationofthepeptidebondbetweenanytwoaminoacids.PBONDclassifiesthepeptidebondsintooneoutoffourclasses,namelycisimide(cis-Pro),cisamide(cis-nonPro),transimide(trans-Pro)andtransamide(trans-nonPro).Moreover,foreverypredictionareliabilityindexiscomputed.Theunderlyingstructureoftheserverconsistsofthreestages:(1)featureextraction,(2)featureselectionand(3)peptidebondclas-sification.PBONDcanhandlebothsinglesequencesaswellasmultiplesequencesforbatchprocessing.Thepredictionscaneitherbedirectlydownloadedfromthewebsiteorreturnedviae-mail.ThePBONDwebserverisfreelyavailableathttp://195.251.198.21/pbond.html.
简介:Thispaperpresentsamoleculardynamicssimulationofthebehavioursofnon-polardropletsmergingandalsothefluidmoleculesinteractingwithahydrophobicsurface.Suchbehavioursandtransportphenomenaarepopularingeneralmicro-channelflowboilingandtwo-phaseflow.ThedropletsareassumedtobecomposedofLennards-Jonestypemolecules.Periodicboundaryconditionsareappliedinthreecoordinatedirectionsofa3-Dsystem,wherethereexisttwoliquiddropletsandtheirvapour.Thetwodropletsmergewhentheycomewithintheprescribedsmalldistance.Themergingoftwodropletsapartfromeachotheratdifferentinitialdistancesistestedandthepossiblelarger(orcritical)non-dimensionaldistance,inwhichdropletsmergingcanoccur,isdiscussed.TheevolutionofthemergingprocessissimulatednumericallybyemployingtheMolecularDynamics(MD)method.Forinteractionswithhydrophobicsolidwall,asystemwithfluidconfinedbetweentwowallsisusedtostudythewettingphenomenaoffluidandsolidwall.Theresultsarecomparedwiththoseofhydrophilicwalltoshowtheuniquecharacteristicsofhydrophobicinteractionsbymicroscopicmethods.
简介:Themicromorphologiesofsurfacesofseveraltypicalplantleaveswereinvestigatedbyscanningelectronmicros-copy(SEM).Differentnon-smoothsurfacecharacteristicsweredescribedandclassified.Thehydrophobicityandanti-adhesionofnon-smoothleafsurfaceswerequantitativelymeasured.Resultsshowthatthemorphologyofepidermalcellsandthemor-phologyanddistributiondensityofepicuticularwaxdirectlyaffectthehydrophobicityandanti-adhesion.Thesurfacewithuniformlydistributedconvexunitsshowsthebestanti-adhesion,andthesurfacewithregularlyarrangedtrellisunitsdisplaysbetteranti-adhesion.Incontrast,thesurfacewithrandomlydistributedhairunitsperformsrelativelybadanti-adhesion.Thehydrophobicmodelsofpapilla-ciliaryandfold-setalnon-smoothsurfacesweresetuptodeterminetheimpactsofgeometricparametersonthehydrophobicity.Thisstudymayprovideaninsightintosurfacemachinemoldingandapparentmorphologydesignforbiomimeticsengineering.
简介:Bionicnon-smoothsurfaces(BNSS)canreducedrag.Muchattentionhasbeenpaidtothemechanismofshearstressreductionbyriblets.Themechanismofpressureforcereductionbybionicnon-smoothsurfacesonbodiesofrevolutionhasnotbeenwellinvestigated.InthisworkCFDsimulationhasrevealedthemechanismofdragreductionbyBNSS,whichmayworkinthreeways.First,BNSSonbodiesofrevolutionmaylowerthesurfacevelocityofthemedium,whichpreventsthesuddenspeedupofaironthecrosssection.Sothebottompressureofthemodelwouldnotbedisturbedsharply,resultinginlessenergylossanddragreduction.Second,themagnitudeofvorticityinducedbythebionicmodelbecomessmallerbecause,duetothesculpturing,thegrowthoftinyairbubblesisavoided.Thusthelargemomentofinertiainducedbylargeairbubbleisreduced.Thereductionofthevorticitycouldreducethedissipationoftheeddy.Sothepressureforcecouldalsobereduced.Third,thethicknessofthemomentumlayeronthemodelbecomeslesswhich,accordingtotherelationshipbetweenthedragcoefficientandthemomentumthickness,reducesdrag.
简介:Anon-radioisotopic,quantitativeTRAP-basedtelomeraseactivityassaywasestablishedmainlybyusingSYBRGreen-Istaininginsteadofradioisotope.Comparingwithconventionalradioisotopebasedmethod,itwasbetterinreproducibilityandaccuracy.Usingthismethod,wefoundtelomeraseactivitieswereabsentinnormalhumanlivercells,whiledetectedinalloffourhumanhepatomacelllines(BEL-7404,SMMC-7721,QGY-07903andHCCM)withoutsignificantdifferences.
简介:植物非特定的类脂化合物转移蛋白质(nsLtps)被报导了对细菌、真菌的病原体涉及植物防卫活动。在这研究,我们识别了135(122通常认为并且13以前识别了)SolanaceaensLtps,它被聚类进8个不同的组。由与Boutrot的nsLtp分类作比较,我们分类这八个组进五种类型(我,II,IV,IX和X)。我们把SolanaceaensLtps与Arabi-dopsis和GramineaensLtps作比较并且发现(1)那打字我,II和IV被Solanaceae,Gramineae和Arabidopsis分享;(2)类型III,V,VI和VIII被Gramineae和Arabidopsis分享然而并非到目前为止在Solanaceae检测了;(3)而类型IX在Arabidopsis和Solanaceae仅仅是在场的,类型VII仅仅在Gramineae被发现;(4)类型X是在我们的数据说明52.59%SolanaceaensLtps的一种新类型,并且到目前为止没在任何另外的植物被报导。我们进一步造了并且比较了八个组的三维的结构,并且发现在nsLtp家庭以内的主要功能的多样化能被早于到monocot/dicot分叉,并且许多基因复制和顺序变化在monocot/dicot分叉以后发生在nsLtp家庭,特别在Solanaceae。
简介:Thebodysurfaceofsomeorganismshasnon-smoothstructure,whichisrelatedtodragreductioninmovingfluid.Toimitatethesestructures,modelswithanon-smoothsurfaceweremade.Inordertofindarelationshipbetweendragreductionandthenon-smoothsurface,anorthogonaldesigntestwasemployedinalowspeedwindtunnel.Sixfactorslikelytoinfluencedragreductionwereconsidered,andeachfactortestedatthreelevels.Thesixfactorsweretheconfiguration,diameter/bottomwidth,height/depth,distribution,thearrangementoftheroughstructuresontheexperimentalmodelandthewindspeed.Itwasshownthatthenon-smoothsurfacecausesdragreductionandthedistributionofnon-smoothstructuresonthemodel,andwindspeed,arethepredominantfactorsaffectingdragreduction.Usinganalysisofvariance,theoptimalcombinationandlevelswereobtained,whichwereawindspeedof44m/s,distributionofthenon-smoothstructureonthetailoftheexperimentalmodel,theconfigurationofriblets,diameter/bottomwidthof1mm,height/depthof0.5mm,arrangedinarhombicformation.Attheoptimalcombinationmentionedabove,the99%confidenceintervalfordragreductionwas11.13%to22.30%.
简介:Lasermultipleprocessing,i.e.lasersurfacetexturingandthenLaserShockProcessing(LSP),isanewsurfaceprocessingtechnologyforthepreparationofbionicnon-smoothsurfaces.Basedonengineeringbionics,samplesofbionicnon-smoothsurfacesofstainlesssteel0Crl8Ni9weremanufacturedintheformofreseaustructurebylasermultipleprocessing.Themechanicalproperties(includingmicrohardness,residualstress,surfaceroughness)andmicrostructureofthesamplestreatedbylasermultipleprocessingwerecomparedwiththoseofthesampleswithoutLSPTheresultsshowthatthemechanicalpropertiesofthesesamplesbylasermultipleprocessingwereclearlyimprovedincomparisonwiththoseofthesampleswithoutLSPThemechanismsunderlyingtheimprovedsurfacemicrohardnessandsurfaceresidualstresswereanalyzed,andtherelationsbetweenhardness,comnressiveresidualstressandroughnesswerealsopresented.