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简介：本文主要介绍了有关内存的一些概念,探讨了’386微处理器且带有扩展内存的PC机内存管理的优化问题.对于拥有80286或’386微处理器PC机的用户来说,本文无疑是雪中送炭。

简介：摘要目的本研究旨在应用LC/MS/MS鉴定Caco-2细胞中吴茱萸次碱的代谢产物，推测其代谢途径。方法在Caco-2细胞中加入100μM吴茱萸次碱处理3h、6h、12h，其后收集并纯化样品，LC/MS/MS分析鉴定代谢产物。结果吴茱萸次碱的代谢产物是单羟基化吴茱萸次碱M1。结论LC/MS/MS灵敏、操作简单，可快速鉴定Caco-2细胞中的吴茱萸次碱的代谢产物。

简介：SignificantanomalieswereobservedatthegeomagneticstationsinthesouthwestregionofChinabeforetheYingjiangMS6.1earthquakeandtheLudianMS6.5earthquakein2014.Weprocessedthegeomagneticverticalcomponentdiurnalvariationdatabythespatialcorrelationmethod.TheresultsshowthatduringtheperiodfromApril1toMay20,2014,thereexistedquasi-synchronousdecreasechangesinthecoefficientcurvesbetweenthefivegeomagneticstationsofGuiyang,Hechi,Nanshan,Muli,YongningandXinyiandHongshanstations.Furthermore,therewasahighgradientzoneinthenormalizedcorrelationcoefficientcontourmapwithbackgroundvaluesremoved.TheepicentersoftheYingjiangMS6.1earthquakeandtheLudianMS6.5earthquakearelocatedinthegradientzoneornearthegradientzone.

简介：Theearthquakestress-dropvaluesoftwosequenceswereaccuratelycalculatedaftertakingawaytheeffectsduetoregionalearthquakeanelasticattenuationandstationsiteresponse,usingwaveformdataandseismicphasedataofsequencesoftheJingguM_S6.6,andLudianM_S6.5earthquakesinYunnan.Theseresultsshowthatthestressdropwithmagnitudeincreaseswithinthescopeofthisstudyofmagnitude.Aftereliminatingtheinfluenceofthemagnitude,theaveragevalueofstress-dropintheJinggusequenceishigherthanthatoftheLudiansequenceatthesamemagnituderange.Thismayberelatedtothestressstateindifferentregions.Intermsofthechangesoftimeandspaceofstress-drop,beforeM_S5.8strongaftershock,thestress-dropis'slowingdown-turningup-keepingahighvalue'afterthemainshock,meanwhile,almostalloftheabnormallyhighstressdropvalueisdistributedaroundtheM_S5.8strongaftershock,showingthatthestressenvironmentintheregionwasincreasingafterthemainshock.AndaftertheM_S5.9strongaftershock,stress-droprapidlydeclinestoarelativelystablestate,meanwhile,thehighvalueofstress-dropisdistributedaroundthestrongaftershock,showingthattheregionaltectonicstressgetsmorefullyrelease,itsstressenvironmentbeginstorapidlydecrease.FortheLudiansequencewithoutastrongaftershockoccurring,theaveragevalueofstressdropislowerthanthatoftheJingguearthquakesequenceatthesamemagnituderange,whileatthesametime,thestress-dropoftheaftershocksequencealmosthasn'tchangedmuch.Inthetimeafterthemainshock,combinedwiththereleasecharacteristicsofthemainenergy,thestressintheregionisexcessivelyreleased,thesubsequentstressintheregiongraduallyreturnstonormal.ThismaybethereasonwhytheactivityofLudianaftershockssignificantlywasweakerandsubsequentlytherewerenostrongaftershocksoccurred.

简介：目的：建立HPLC-MS/MS法测定人尿液中依普利酮的浓度。方法：用蛋白质沉淀法处理尿液,采用WatersSymmetryC18色谱柱（50mm×4.6mm,5μm）,流动相为甲醇（A）-乙腈（B）-1mmol/L乙酸铵水溶液（C）,梯度洗脱（0.01min：15%A,85%C;0.8min：100%A;2.1min50%A,50%B;2.11~3.5min：15%A,85%C）;流速：1.0ml/min,柱温：40℃,采用电喷雾离子源,正离子扫描模式检测。考察该方法的专属性、标准曲线、定量下限、精密度、回收率、基质效应和稳定性。结果：依普利酮尿液浓度在5~2000ng/ml范围内线性关系良好（r〉0.9968）,定量下限为5ng/ml。批内精密度RSD〈4.31%,批间精密度RSD〈6.69%,提取回收率在94.41%~98.47%,基质效应在83.97%~99.22%（n=6）。结论：该法准确、灵敏,重复性好,可用于依普利酮在人尿液中浓度的测定。

简介：目的建立超高效液相色谱-串联质谱（UPLC—MS／MS）法测定人血中雪上一枝蒿甲素含量的方法。方法样品经乙酸乙酯提取后，Ci8柱分离，以0．1％甲酸乙腈-0．1％甲酸水为流动相梯度洗脱，正离子-多反应离子监测模式（ESI＋-MRM）测定雪上一枝蒿甲素，定性定量离子对分别为344．3／58．0、344．3／91．0。结果雪上一枝蒿甲素在3．5～850ug／L-1。范围内与峰面积呈现良好的线性关系（r=-0．9968），检测限为0．1Iμg／L-1，日内、日间精密度均〈10％，低、中、高三个浓度下准确度（n=5）为97．2％-115．2％，回收率（n=5）为86．6％~89．4％。结论该方法操作简便，结果准确，可作为测定人血中雪上一枝蒿甲素含量的方法。

简介：目的：建立乌头中毒致死的动物检材中乌头类生物碱的LC/MS/MS分析方法。方法：将生物检材用氨水调pH值为8-9,用氯仿/乙醚（1：4）萃取生物检材样品,采用电喷雾离子源,正离子模式检测。结果：在中毒致死的动物检材中发现了乌头碱、中乌头碱和次乌头碱。结论：LC/MS/MS法灵敏可靠,样品处理快速简便,适用于生物检材中乌头类生物碱的检测。

简介：目的：研究罗通定在大鼠胆汁中的主要代谢产物。方法：灌胃给药后，收集大鼠胆汁，液液萃取，采用HPLC／MS／MS法分析鉴定罗通定的代谢产物。色谱柱Lichrospher-C18（5μm，4．6mm×250mm），流动相：甲醇-水-三乙胺（37：63：0．063，V／V／V），冰醋酸调pH至6．3，检测波长281nm。结果：在大鼠胆汁中发现2个罗通定代谢产物，初步推测其结构为罗通定单羟基化后再与葡萄糖醛酸结合的产物。结论：罗通定在大鼠胆汁中主要以羟基化后的葡萄糖醛酸结合物形式排泄。

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简介：摘要：目的：建立一个用液相色谱－质谱联用法测定中药材中黄曲霉毒素含量的方法。方法：色谱柱：thermo Scientific Hypersll GOLDTM(1.9μm，2.1×100mm)；流动相: 乙腈-10mmol/L的甲酸铵水溶液，梯度洗脱；流量: 0.3 ml/min；以三重四极杆串联质谱仪检测；柱温:25 ℃。结果：根据药材基质的不同，优化得出相应满足方法要求的前处理方法并进行了验证。结论：该方法可用于中药材中黄曲霉毒素含量的测定。

简介：摘 要：本文建立了一种通过UPLC-MS/MS测定定西宽粉中米酵菌酸含量的快速检测方法。样品经甲醇-氨水溶液提取后，过0.22µm有机滤膜，上UPLC-MS/MS测定。结果表明，米酵菌酸的质量浓度在1~100ng/mL范围内与色谱峰面积的线性关系良好，R 为0.9996，检出限1.0µg/kg。RSD小于5%（n=6），加标回收率在60%-120%之间。该方法处理样品简单、快捷、检出限低、精密度高，定性、定量准确。

简介：摘要：随着近几年来我国社会各方面的建设发展，科学水平的高速发展正在逐渐开始促进现如今我国社会各行各业的创新进步与发展，并且现代人民群众的生活水平与质量日益提升，对于生活中所面临的诸多方面要求也逐渐开始有所提高，比如人们的衣食住行等问题，在现代经济富足的环境影响下，人们更加重视起食品的安全性来，并且现代食品中经常会发现较多的有害化合物与添加剂，对现代人民群众的健康造成了严重的威胁。基于此，将LC-MS/MS技术应用于食品质量与安全研究中，对现代我国社会食品安全方面的问题做出保障。

简介：摘要磁共振血管成像（3D-TOF-MRA）是一种全新的无损伤性血管成像方法，具有无创伤和无放射性损害、经济快捷、适应症广、大部分病例不用造影剂即可明确诊断等优点广泛应用于临床。本文对532例3D-TOF-MRA检查进行分析，结果197例显示正常占37%，颅内动脉硬化217例占40%，颅内动脉狭窄(或闭塞)168例，占31%，颅内动脉静脉畸形7例占1%，动脉瘤17例占3%，发育异常9例，约1%。结论3D-TOF-MRA的临床应用价值已经得到广泛的肯定，是脑血管疾病的主要检查方法。

简介：X射线光电子能谱仪（XPS）和飞行时间二次离子质谱（TOF-SIMS）作为浅表面化学分析的两种重要手段,能够高精度的提供村料表面丰富的物理化学信息,在诸多行业的科学研究中被广泛应用.本文通过设备原理分析,结合具体应用实例,对XPS和TOF-SIMS在PCB失效分析的应用做了简单探讨.

简介：1前言蛋白组学研究是目前生命科学研究领域中的一大热点,蛋白组学研究中的关键技术之一是如何得到准确的多肽指纹谱图,以保证蛋白质的准确定性.基于方便、快速、简捷的要求,基体辅助激光解吸电离-飞行时间质谱(MALDI-TOF)技术是目前分析多肽指纹谱图中最常用的方法.

简介：摘要目的评价血清分离胶促凝管法和HB&L微生物培养体系两种MALDI-TOF-MS预处理方法的鉴定率，为临床快速准确鉴定血流感染病原菌提供新思路。方法收集2020年1—12月北京解放军总医院第六医学中心实验室常规方法鉴定的149份血培养报警后单一细菌感染的阳性样本，分别采用分离胶促凝管法和HB&L微生物培养体系预处理后，并且以传统方法结果为标准，直接MALDI-TOF MS细菌鉴定，比较两种方法的鉴定率。结果在149份血培养阳性样本中，革兰阴性（G-）菌占47.0%（70/149）、革兰阳性（G+）菌占53.0%（79/149）。对G-菌种水平鉴定率，血清分离胶促凝管法为78.6%（55/70），HB&L微生物培养体系为91.4%（64/70），差异有统计学意义（P=0.033）；对G+菌种水平鉴定率，二者分别为73.4%（58/79）和87.3%（69/79），差异有统计学意义（P=0.028）。在3.000~2.300分值段，G-菌鉴定率血清分离胶促凝管法和HB&L微生物培养体系分别为22.9%（16/70）和38.6%（27/70），差异有统计学意义（P=0.044）；G+菌鉴定率两种方法分别为19.0%（15/79）和34.2%（27/79），差异有统计学意义（P=0.031）。结论HB&L微生物培养体系种水平鉴定率要高于血清分离胶促凝管法，经过预处理直接MALDI-TOF MS鉴定血培养阳性样本病原菌有一定临床应用价值。

简介：AbstractBackground:The human brain is the most complex organ in the body, and it is important to have a better understanding of how the protein composition in the brain regions contributes to the pathogenesis of associated neurological disorders.Methods:In this study, a comparative analysis of the frontal and temporal cortex proteomes was conducted by isobaric tags of relative and absolute quantification (iTRAQ) labeling and two-dimensional liquid chromatography-tandem mass spectrometry (2D LC-MS/MS). Brain protein was taken from relatively normal tissue that could not be avoided of damage during emergent surgery of the TBI (traumatic brain injury) patients admitted in Beijing Tiantan Hospital from 2014 to 2017. Eight cases were included. Four frontal lobes and 4 temporal lobes proteome were analyzed and the proteins were quantitated. Gene Ontology (GO), Ingenuity Pathway Analysis (IPA), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to analyze the biological function of identified proteins, unchanged proteins, and differentially expressed proteins (DEPs).Results:A total number of 2127 protein groups were identified in the frontal and temporal lobe proteomes. A total of 1709 proteins could be quantitated in both the frontal and temporal cortex. Among 90 DEPs, 14 proteins were screened highly expressed in the temporal cortex, including MAPT, SNCG, ATP5IF1, GAP43, HSPE1, STMN1, NDUFS6, LDHB, SNCB, NDUFA7, MRPS36, EPDR1, CISD1, and RALA. In addition, compared to proteins expressed in the frontal cortex, 14 proteins including EDC4, NIT2, VWF, ASTN1, TGM2, SSB, CLU, HBA1, STOM, CRP, LRG1, SAA2, S100A4, and VTN were a low expression in the temporal cortex. The biological process enrichment showed that unchanged proteins between the frontal and temporal cortex mainly take part in regulated exocytosis, axon guidance, and vesicle-mediated transport. The KEGG pathway analysis showed that unchanged proteins between the frontal and temporal cortex mainly take part in oxidative phosphorylation, carbon metabolism, Huntington's disease, and Parkinson's disease.Conclusions:The majority of proteins are unchanged between the frontal and temporal cortex, and unchanged proteins are closely related to its function. Among DEPs, MATP (tau) is upregulated in the temporal cortex, closely related to Alzheimer's disease (AD), and is one of the targets for the treatment of AD. CLU is downregulated in the temporal cortex which functions as an extracellular chaperone that prevents aggregation of non-native proteins. It was suggested that the temporal lobe may not be the "functional dumb area" of the traditional view, but could be involved in important neural metabolic circuits.

简介：目的：采用HPLC-MS/MS法分析鉴定罗通定在大鼠胆汁中的主要代谢产物。方法：罗通定灌胃给予大鼠（120mg·kg^-1）,收集胆汁样品。色谱分离采用ZorbaxSBC18（150mm×0.5mmI.D.,5μm）;流动相：甲醇-水-三乙胺（30：70：0.07,V/V/V）;质谱分析采用（＋）ESI模式。结果：在大鼠胆汁中观察到4个罗通定代谢产物,初步推测其中2个为罗通定去甲基化后再与硫酸结合的产物。结论：去甲基化后形成硫酸结合物为罗通定在大鼠胆汁中一主要排泄形式。

简介：Panaxnotoginsengsaponins(PNS)arethemajorcomponentsofPanaxnotoginseng,withmultiplepharmacologicalactivitiesbutpoororalbioavailability.PNScouldbemetabolizedbygutmicrobiotainvitro,whiletheexactroleofgutmicrobiotaofPNSmetabolisminvivoremainspoorlyunderstood.Inthisstudy,pseudogerm-freeratmodelswereconstructedbyusingbroad-spectrumantibioticstovalidatethegutmicrobiota-mediatedtransformationofPNSinvivo.Moreover,ahighperformanceliquidchromatography-electrosprayionizationtandemmassspectrometry(HPLC-ESI-MS/MS)wasdevelopedforquantitativeanalysisoffourmetabolitesofPNS,includingginsenosideF1(GF1),ginsenosideRh2(GRh2),ginsenosidecompoundK(GCK)andprotopanaxatriol(PPT).Theresultsshowedthatthefourmetabolitescouldbedetectedinthecontrolratplasma,whiletheycouldnotbedeterminedinpseudogerm-freeratplasma.TheresultsimpliedthatPNScouldnotbebiotransformedeffectivelywhengutmicrobiotawasdisrupted.Inconclusion,gutmicrobiotaplaysanimportantroleinbiotransformationofPNSintometabolitesinvivo.