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法医学和人类身份鉴定

法医科学家通常运用各种分析方法确定在犯罪现场发生了什么以及谁可能
参与其中。检测包括指纹分析、DNA分析、弹道学和化学分析。

DNA分析的应用包括:

  • 快速STR分析;
  • 罪犯DNA数据库建立;
  • 法医学DNA生活环境调查 - 将已知的样本和未知样本进行配对;
  • 亲子鉴定 - 鉴定家庭成员;
  • 失踪人口调查;
  • 灾难受害者身份鉴定;
  • 军队DNA“狗牌” - 用于军人的DNA鉴定文件;
  • 遗传学研究/人口研究。
  • 利用短串联重复序列(STR)分析进行DNA分型

    DNA分析是用于法医学调查的最强有力的工具之一,因为它在鉴定细胞材料时具有统计学意义,比如随机选择一个人时,一份收集的DNA片段属于另外一个人的概率要低于十亿分之一。

    现代法医科学家们从人的细胞中收集到短DNA片段(称为短串联重复序列STR),并且通过荧光标记和自动设备进行测量。对这些STR的DNA分析允许法医科学家们基于这些检测结果得出结论。由于STR在不同个体之间都不一样,因此它们对鉴定人类的身份非常有用。

    在整个人类基因组中都发现了STR。全世界的法医学科学家们利用介于13和24个STR位点(称作基因座)为每个罪犯个人建立DNA分型。GE医疗提供工具:FTA口腔卡/血卡和DNAScan快速DNA分析系统,有力地帮助从罪犯、被捕人员和犯罪嫌疑人中收集和分析DNA以生成DNA谱。DNA谱放入全球数据库中,同时用来确定人们是否参与到未破案的犯罪。

    FTA技术---法医学的未来

    GE医疗生命科学的FTA技术节省您的时间和体力,包括您样品流程的每个步骤,从罪犯样品收集到DNA分析。FTA技术提供一种高效的方法用于DNA样品收集、运输和在室温下存储几十年。FTA卡与纯化试剂一起使用,而不需要另外的试剂,并且与手动或自动打孔器和样品处理机器人兼容。FTA卡的使用将促进工作流程的标准化并显著提高工作效率。

    关于定制型FTA试剂盒的信息,联系您当地的GE医疗代表

    Much of GE Healthcare's filtration media are available in either flat format or in encapsulated formats, such as syringe filters, capsule filters, and filtration microplates.

    • Flat filters: Circles or sheet format. Circles would normally be used in an appropriate filter holder.
    • Prepleated filters (only for cellulose papers): Prefolded/pleated filter paper circles for use in conical filter funnels.
    • Syringe filters: Small, encapsulated, disposable filter units intended for filtration of small sample volumes using a syringe.
    • Syringeless filters/filter vials: Encapsulated, disposable filter units for small volume sample preparation not requiring the use of a syringe to drive the filtration step.
    • Inline filters: Encapsulated, disposable filter units intended for connection to flexible tubing. Units are available for filtration of liquids and for air/gas applications.
    • Capsule filters: Disposable filter units incorporating pleated filter media for larger volumes of liquid and air/gas applications.
    • Filtration microplates: Microplates with incorporated filter media for simultaneous filtration of multiple samples.

     

    Filter characteristics and typical properties

    The selection of a laboratory filter depends on the conditions and objectives of your experiment or analytical procedure. The three most important characteristics of any laboratory filter are:

    • Particle retention efficiency
    • Fluid flow rate through the filter
    • Loading capacity

    According to your particular application, other important filter characteristics may also require examination, for example wet strength, chemical resistance, purity, and ash level. 

    Typical properties of filter papers and glass fiber filters

    Membrane materials

    Chemical compatibility chart of membranes and housings


    Filtration Methods for flat filters

      Gravity Vacuum Pressure
    Cellulose Filter Papers Suitable Suitable Not generally used
    Glass Microfiber Not suitable Suitable Suitable
    Membranes Not suitable Suitable Suitable


    Maximum practical volumes of cellulose filter paper circle sizes (quadrant folded)

    Volume (ml) 15 20 35 75 135 300
    Filter Diameter (mm) 90 110 125 150 185 240

     

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