简介:4-Amino-5-(pyridin-3-yl)-4H-1,2,4-triazole-3-thiol1werecondensedwith2-bromo-1-(substitutedphenyl)ethanonetogivepyridinyltriazolothiadiazines2a~c,whichwerequaternarizedwithmethyliodideandoxidizedwith30%hydrogenperoxidetoaffordthecorrespondingmethylpyridiniumsalts3a~candpyridine-l-oxides4a~c,respectively.Thereductionofcompounds3and4withNaBH4inmethanolproducedthetargetcompounds1-methyl-1,2,5,6-tetrahydropyridin-3-yl)-6-aryl-s-triazolothiadiazines5a~cand3-(1-hydroxyl-1,2,5,6-tetrahydropyridin-3-yl)-6-aryls-triazolothiadiazines6a~c,respectively.Theendotheliumvascularrelaxingactivityofthetargetcompoundswasscreened.
简介:FollowingtheeruptionofEuropeandebtcrisisinthewakeofthefinancialcrisis,anewdebtcrisisbegantofermentontheUSsoils.OnMay16th,withUSdebtexceedingitsstatutoryceilingof$14.29trillion,USTreasury'ssolvencybecamesostretchedthatitcouldhardlylasttoAugust2nd.Asaresult,thecountrywasplungedintogreatdefaultrisks.Thetwoparties,throughheatedpoliticalstruggles,finallymanagedtoreach
简介:成长观察表明软gamma光线重复ers和异常x-raypulsars是磁铁艺术。他们的磁场可以完成10(14)-10(15)G。我们由在中子星(NS)内考虑P-3(2)超流体中子的磁化探索超级强壮的磁场的起源。由Elgaroy由和状态的方程解决Tolman-Oppenheimer-Volkov方程采用了它等。[Phys。加快。Lett。77(1996)1428]在配对差距的中子的计算,我们明确地计算NS内部结构,为在NS内的P-3(2)超流体中子的可允许的区域,和有序的安排中子旋涡贡献的全部的磁性的时刻。结果证明导致的磁场可以盖住一个宽范围,它与磁场下面为脉冲星纺纱由标准磁性的偶极子放射预言了一致。
简介:Thispaperstudiesthemodel-robustdesignproblemforgeneralmodelswithanunknownbiasorcontaminationandthecorrelatederrors.ThetrueresponsefunctionisassumedtobefromareproducingkernelHilbertspaceandtheerrorsarefittedbytheqthordermovingaverageprocessMA(q),especiallytheMA(1)errorsandtheMA(2)errors.Inbothsituations,designcriteriaarederivedintermsoftheaverageexpectedquadraticlossfortheleastsquaresestimationbyusingaminimaxmethod.Acaseisstudiedandtheorthogonalityofthecriteriaisprovedforthisspecialresponse.Therobustnessofthedesigncriteriaisdiscussedthroughseveralnumericalexamples.
简介:WediscussthebosonizationofarelativisticverydenseFermigasinamagneticfieldandtheconsequentBoseEinsteincondensationoftheresultingrelativisticvectorgasofchargedparticles.Themodelmaybeappliedtopairedspin-upelectrons.Weshowthatsuchsystemsmaymaintainself-consistentlymagneticfieldsoforder10^10-10^13G.Thatpairingcouldbetheoriginoflargemagneticfieldsinsomewhitedwarfsandneutronstars.Forfieldslargeenough(-10^13forwhitedwarfs),thesystembecomesunstableandcollapses.
简介:Themechanismofesterhydrolysishasbeenextensivelystudied;however,theprecisefunctionofactive-siteresiduesinpromotingcatalysisisunclear.WedescribeherethestructuralmodelsforthecomplexofacatalyticantibodyFvfragmentwithaphosphonatetransition-stateanalogue,constructedbyusinggenecloning,sequencingandmolecularmodeling,mainlybasedonaknownX-raystructureofacatalyticantibody.HydrophobicandelectrostaticanalysesoftheFv/analogandFv/substrateinteractionsuggestthehydrolysismechanism:TyrL91andTyrH97playimportantrolestostabilizetheβ-naphthylgroupofhaptenthroughπ-stack;HisH35donatesapairoffreeelectronsattheatomNE2toanactivewaterandletittobeapartialhydroxide,whichattacksthecarbonatomofthecarbonylgroupofthesubstrate.BothHisH35andArgL96canformhydrogenbondsandstabilizetheanionictetrahedralintermediateformedduringturnover.Thismechanismemphasizesthatanactivewaterbridgemaybeformedduringhydrolysisprocess.