学科分类
/ 4
77 个结果
  • 简介:ThesynthesisofcalciumformatebyCa(OH)2carbonylationwasstudiedinasemi-batchstirredtank.Thereactionmechanismwasanalyzedtheoreticallyandtherateofeachstepwascompared.Theinfluenceofreactionconditionsontheformationofcalciumformatewasinvestigated.Theresultsindicatethattherate-controllingstepisthereactionbetweendissolvedCOanddissolvedCa(OH)2,andthegaseousdiffusionresistancecanbeeliminatedwhenthestirringspeedreached1000r/min.Furthermore,thereactionkineticswasstudiedatastirringspeedof1000r/min,temperatureof423–453K,pressureof2.0–3.5MPaanddifferentinitialconcentrationsofCa(OH)2.AneffectivemethodwasproposedtomeasurethereactionrateofCO.Amathematicalmodelwasdevelopedusingthedual-filmtheory,andtheparameterswereobtainedusingregressionofexperimentaldata.Thereactionratescalculatedusingthekineticsmodelwerecomparedwithexperimentaldata.Theresultsshowthatthedeviationsarewithin±10%,provingthattheestablishedmodelisvalidandcanprovideabasisforindustrialamplification.

  • 标签: CALCIUM HYDROXIDE CARBONYLATION CALCIUM FORMATE KINETICS
  • 简介:Coronaryarterycalcification(CAC)isasanindependentriskpredictorofcardiovasculardiseaseandcanclassifyanindividual’sriskofatheroscleroticcardiovasculardisease,particularlyinintermediate-riskindividuals.Also,CACprogressionisassociatedwithgreaterratesofcardiovascularevents.ThisarticleprovidesavailabledataandexpertrecommendationsforCACbasedoncurrentpublications.WefocusontheutilityofCACforstratificationofindividualsanddescribeitsdiagnosticvalueinidentifyingpatientsatrisk.WealsodescribetheimportantabilityofCACtoderiskapatientwithascoreofzero.

  • 标签: CORONARY ARTERY calcifi CATION ASCVD RISK
  • 简介:Calciumisimportantforourhealth.Wemusthaveitinourdiettostaywell.Agoodplacetogetitisfromdairyproductslikemilk,cheeseandicecream.Onepoundofcheesehasfiftytimesthecalciumweshouldhaveeveryday.Otherfoodshaveless.Forexample,apoundofbeansalsohascalcium.Butithasonlythreetimestheamountweoughttohavedaily.

  • 标签: 高中 英语 科普知识 阅读练习
  • 简介:ThelocalCa^2+releasefromtheheterogeneouslydistributedendoplasmicreticulum(ER)calciumstorehasacriticalroleincalciumhomeostasisandcellularfunction.However;singlefluorescentproteinbasedERcalciumprobesexperiencechallengesinquantifyingtheERcalciumstoreindifferinglivecells,andintensity-basedmeasurementsmakeitdifficulttodetectlocalcalciummicrodomainsintheER.Here,wedevelopedageneticallyencodedratiometricERcalciumindicator[GCEPIA1-SNAPer]thatcandetectthereal-timeERcalciumstoreandlocalcalciummicrodomainsinlivecells.GCEPIA1-SNAPerwaslocatedinthelumenoftheERandshowedalinear;reversibleandrapidresponsetochangesintheERcalciumstore.TheGCEPIA1-SNAPerprobeeffectivelymonitoredthedepletionoftheERcalciumstorebyTGorstarvationtreatment,andthrough让suseweidentifiedheterogeneouslydistributedcalciummicrodomainsintheERwhichwerecorrelatedw让hthedistributionofSTIM1clustersuponERcalciumstoredepletion.Lastly,GCEPIA1-SNAPercanbeusedtodetecttheERcalciumstorebyhigh-throughputflowcytometryandconferstheabilitytostudythefunctionofcalciummicrodomainsoftheER.

  • 标签: RATIOMETRIC CALCIUM sensor LOCAL CALCIUM microdomain
  • 简介:Objective:Tostudytheeffectofelectroacupuncture(EA)andVerapamilandNifedipine(calciumchannelinhibitors)onfreecalciumconcentrationsofcellsandintrasynaptosomesinhypothalamus(HT),periaqueductualgreymatter(PAG)andhippocampus(HIP)ofmice.Methods:ThefemaleICRmicewererandomlydividedintocontrol,EA,CaCl2andCaCl2+EAgroups(n=8ineachgroup).Painthresholdwasdetectedbyusingradiation-heatirradiation-inducedtailflickmethod.EA(8Hz,asuitablestimulatingstrength,dense-sparsewavesanddurationof30min)wasappliedto'Shuigou'(水沟GV26)and'Chengjiang'(承浆CV24).CaCl2(10μL,0.2μmol/L)wasinjectedintothelateralcerebralventricleofmiceafterEA.Theconcentrationsofcytosolicfreecalcium([Ca2+]i)inHIP,PAG,HTcellsuspensionspecimenandhippocampalintrasynaptosomesuspensionofmiceweredeterminedbythefluorescentcalciumindicatorFura-2-AMandaspectrofluorometer.Results:DuringEAanalgesia,theintracellularfree[Ca2+]iinHTandPAGspecimensandintrsynaptosomal[Ca2+]iofthe3cerebralregionsdecreasedconsiderably(P<0.05~0.01),butthatinhippocampalcellsuspensionincreasedsignificantly(P<0.01)incomparisonwithcontrolgroup.Theconcentrationsofhippocampalintrasynaptosomalfree[Ca2+]idecreasedsignificantlyafteraddingVerapamilandNifedipinetotheextractedhippocampalintrasynaptosomalspecimen.MicroinjectionofCaCl2intolateralventriclehadnoapparentinfluenceondegreeofanalgesia(DA)%andintracellularandintrasynapsotomal[Ca2+]i,butsignificantlylowerDA%andreducechangesofcytosolicandintrasynaptosomal[Ca2+]iinducedbyEAstimulation.Conclusion:CalciumionintheneuronsandintrasynaptosomeofHT,PAGandHIPisinvolvedinelectroacupunctureanalgesia.

  • 标签: 电针疗法 钙离子通道 细胞质 脑细胞 中医治疗
  • 简介:CalciumhydroxytitanateformedinBayerdigestionprocessofchinesediasporicbauxitewasstudied.InterplanarspacingsofcalciumhydroxytitanatecrystalweredeterminedbyXRDanalysis.Onlyoneendothermicpeakoccursat550~560℃ontheDTAcurveofthiscompound.IRspectrometrystudyhasrevealedthathydroxyldoesexistincalciumhydroxytitanateinsteadofcrystalwater.ObservationunderSEMhasindicatedthatitscrystalgrainsareintheshapeofregularhexagonalplateswith2~8μminedgelengthandlessthan1μminthickness.TheinfluencesofvariousdigestionconditionsontheformationandtransformationofcalciumhydroxytitanateandotherCa-Ti-containingcompounds,suchaslimeaddition;contentanddistributionstateofTiO2inbauxite;digestiontemperatureandretentiontime,werefurtherstudied.

  • 标签: DIGESTION retention BAYER HYDROXYL BAUXITE hexagonal
  • 简介:

  • 标签:
  • 简介:AbstractBoth fatty acids (FAs) and calcium ions play important roles in contraceptive cycles via several systems. Polyunsaturated FAs (PUFAs) act as precursors for prostaglandin production and can alter the expression of numerous crucial catalysts that are involved in prostaglandin and steroid digestion. Lipids are essential components of cell membranes. A diet rich in PUFAs enhances sperm motility and viability. It also improves testis development and spermatogenesis in several domesticated animal species. Increased PUFA content in spermatozoa increases plasma membrane fluidity, which is important for fertilization. However, the major drawback of high dietary PUFA intake is that it increases the levels of reactive oxygen species in the body. An increase in reactive oxygen species levels markedly affects fertility. Calcium is an important component that acts as an intra-cellular secondary messenger and plays an important role in some of the physiological processes that occur in male gametes. Some of these processes include spermatogenesis, sperm motility, capacitation, acrosome response, and fusion of gametes. These processes are associated with calcium influx through ion protein channels. Dietary fat intake is associated with increased intestinal calcium absorption. In this review, we discuss the impact of lipids, particularly PUFAs and monounsaturated FAs, and calcium ions on male reproduction, along with their effects on each other.

  • 标签: Infertility treatment Male infertility Motility regulation Polyunsaturated fatty acids Sperm motility
  • 简介:环境友好thermosettingcomposites被作为矩阵混合小麦面筋(WG)准备,钙碳酸盐(CaCO3)由在120掳C塑造混合到交叉连接的压缩作为可塑剂作为filler和甘油列在后面WG矩阵。形态学观察证明CaCO3粒子细微地在矩阵被驱散。直到进composites的10wt%的CaCO3的加入引起了幼仔的模量和张力的力量显著地增加。在另一方面,在裂缝的潮湿吸收和延伸稍微减少了。

  • 标签: 小麦 谷蛋白 碳酸钙 机械力学
  • 简介:Calciumhexaluminate(CA6)wassynthesizedbymixinglight-weightcalciumcarbonateandAl2O3micropowder(calcinedα-Al2O3,activatedα-Al2O3orρ-Al2O3)accordingtothestoichimetricratioofCA6,andreactionsinteringat1200,1300,1400and1500℃for3h,respectively.Effectsofthethreealuminamicropowdersonthephasecomposition,microstructureandpropertiesofCA6wereinvestigated.Theresultsshowthat:(1)forthethreeAl2O3micropowders,thereactiontogenerateCA6inspecimensbasicallycompletesatabout1500℃;CA6generatedinallspecimensisplanar,butthearraymodesareslightlydifferent;(2)thespecimenspreparedfromcalcinedα-Al2O3orρ-Al2O3shrinkalmost,whilethespecimenspreparedfromactivatedα-Al2O3expand;(3)thecoldcrushingstrengthofthespecimenpreparedfromactivatedα-Al2O3isthehighest,reaching42.5MPawhenonlyCA6exists(afterfiringat1500℃);(4)thespecimenpreparedfromρ-Al2O3hasthelowestgenerationtemperatureofCA6andthehighestapparentporosity,reaching70.1%whenonlyCA6exists(afterfiringat1500℃);(5)thespecimenpreparedfromcalcinedα-Al2O3hasthebiggestbulkdensity.

  • 标签: 氧化铝微粉 六铝酸钙 试样制备 性质 CA6 反应烧结
  • 简介:与连续、慢的氧版本特征,过氧化钙(CaO_2)是在污染地下水的简历补习为氧气的微生物供应氧的新来源。批实验被进行评估在包含CaO_2的媒介与水,高酸碱值的规定,以及混合氧气的微生物的生长反应的氧版本率ofCaO_2。结果证明氧版本CaO_2comprises处理三个阶段。当CaO_2的增加的重量增加了,在第一个阶段,严厉地增加的水的溶解的氧层次,和一般水准,氧版本率增加了。然而,率几乎在后者阶段保持不变并且是约0.48和0.084mgO_2?h~(-1),分别地。作为媒介,钾dihydrogen磷酸盐(KH_2PO_4)和硫酸铵的必要部件((NH_4)_2SO_4)能在某个比率调整CaO_2from12.1引起到6.5的范围的酸碱值-8.5,它对微生物引起的生长有用。另外,在包含CaO_2的媒介观察的diauxicgrowth曲线建议混合氧气的微生物的生长能被CaO_2的增加刺激。

  • 标签: 生物治疗 过氧化钙 溶解氧 pH值 生长曲线 好氧微生物
  • 简介:Thispresentstudyinvestigatedtheabilityofvarioussoyproteinhydrolysates(SPHs)inbindingcalcium.ItwasdemonstratedthattheamountofCa-bounddependedgreatlyontheSPHsobtainedusingdifferentproteases,whichincluded:neutrase,flavourzyme,proteaseMandpepsin.ThemaximumlevelofCa-bound(66.9mg/g)occurredwhenproteaseMwasusedtohydrolyzesoyprotein.PeptidefragmentsexhibitinghighCa-bindingcapacityhadmolecularweightsofeither14.4or8-9kDa.ThelevelofCa-boundincreasedlinearlywiththeincrementofcarboxylcontentinSPHs,andfurtherdeamidationonSPHsfromproteaseMimprovedCa-bindingofthehydrolysate.

  • 标签: SOYBEAN protein HYDROLYSATES PROTEASE CALCIUM BINDING
  • 简介:INTRODUCTIONCalciumphosphatecements(CPC)overcomethepracticaldisadvantagesofblocksorgranuleslcanbehandledasapasteandsitinsitu.TheirstructureandcompositionclosetothatofHAPmakethembiocompatiblematerials.2Theconventionalcalciumphosphatecementhadsomeproblemssuchaslongsettingtime(30~60min)andlowcompressivestrength,etc.Inoursystem,anα-TCP/TTCPpowdermixturewasmixedwithwatercontainingcitricacidtocontrolthesettingtimeandcompressivestrength.Inthispaper,theeffectsofvariousconcentrationcitricacidsolutionsonthepropertiesofthecementarereported.

  • 标签:
  • 简介:Objective:Toexplorechemicalcomponentchangesofdogboneatdifferentlengtheningtimeandindifferentboneregionsofinterest,andtoevaluatethemineralizationduringIiizarovlengtheningprocess.Methods:Theashweight,theconcentrationsofcalcium,phosphorusandthecalcium/phosphorusratioweremeasuredatdifferentintervals(2,4,6,8,12weeks)sincelengtheningandthelengthenedpartwascomparedwithacontrolareaateachinterval.Results:Theashweight,theconcentrationsofcalciumandphosphorusinthelengthenedareadifferedatalldevelopmenttime.Thecalcium/phosphorus(Ca/P)ratiointhelengthenedregionremainedsignificantlylowerthanthatinthecontrolregionupto12weeksafterthelengthening.Conclusions:Theseresultssuggestthatalsootherinorganicionsplayanimportantroleinthemineralizationprocessandthattheybecomerelativelymoreimportantsince8weeksafterthelengthening.

  • 标签: 成年犬 骨骼延长术 成骨作用 钙磷成分变化
  • 简介:Anewmethodforthedeterminationoftracecalciumbysolidsubstrate-roomtemperaturephosphorimetryisestablished.ItisbasedonthefactthatchromeazurolsazurolS-phenanthroline-NaCMC(CAS-phen-NaCMC)systemcanemitstrongandstableroomtemperaturephosphorescence(RTF)onthesolidsubstrateinthefilterpaper.Ca2+andphenanthrolinecanformcomplexionCa(phen)32+,whichwillformcomplex[Ca(phen)3(CAS)2]withCAS.Intheresult,thenumberofCASmoleculesineachspotincreased,causingsharpincreaseoftheRTPsignaloftheCAS-phen-NaCMCsystem.

  • 标签: CALCIUM Solid substrate-room temperature phosphorimetry Sodium
  • 简介:ObjectiveToinvestigatethealterationsofL-typecalciumcurrent(IcaL)inabdominalaorticligation-inducedhypertrophiedratheartsandtheeffectoflosartanonthesealterations.METHODSCardiachypertrophywasinducedbyabdominalaorticligationinrats.TorecordIcaL,whole-cellpatch-clamptechniquewasused.RESULTSMembranecapacitancewaslargerinhypertrophiedcells(148±29pF)thaninsham-operatedcells(102±14pF,P<0.01)andlosartan-treatedcells(118±27,P<0.01).ThemaximalpeakIcaLWasincreasedfrom-835±124pAinsham-operatedcellsto-1404+_417pAinhypertrophiedcells(P<0.01),thecorrespondingIcaLdensitywasincreasedfrom-7.5±1.8pA.pF^1to-10.5±2.2pA.pF^1(P<0.01),whiletheywerereducedto-956-2:170pF(P<0.01)and-8.2±1.6pA.pF^1(P<0.05)respectivelyinlosartan-treatedcells.Themembranepotentialofhalfmaximalactivationofthehypertrophiedcells(-20.6±1.0mV)shiftedtomorenegativepotentialsthansham-operatedcells(-15.6±1.6mV,P<0.01)andlorsartan-treatedcells(-17.4±1.0mV,P<0.01).Theslopeoftheactivationcurveofhypertrophiedcells(5.7±0.4)wasdecreasedslightlythansham-operatedcells(6.4±0.5,P<0.05).Themembranepotentialofhalfmaximalinactivationofhypertrophiedcells(-27.6±1.9mV)shiftedtomorepositivepotentialsthansham-operatedcells(-31.4±2.2mV,P<0.05).Theslopeofinactivationcurveswerenotdifferentinthethreegroups.

  • 标签: 心脏肥大 动脉结扎 钙元素 外科手术
  • 简介:Variousfunctionalgroupshavebeensuggestedtoplayessentialrolesonbiomineralizationofcalciumcarbonate(CaCO3)innaturalsystem.2Dand3DmodelsofregularlyarrangedfunctionalgroupshavebeenestablishedtoinvestigatetheireffectonCaCO3crystallization,Thismini-reviewsummarizestherecentprogressandthefuturedevelopmentisprospected.

  • 标签: FUNCTIONAL group BIOMINERALIZATION CRYSTALLIZATION CACO3