排序方式: 共有143条查询结果,搜索用时 15 毫秒
71.
色谱指纹图谱组合相似度的算法 总被引:1,自引:0,他引:1
色谱指纹图谱相似度是评价中药质量稳定性的有效手段之一,其中向量夹角余弦相似度应用最为广泛。但是当色谱峰面积分布范围宽时,夹角余弦对数据的差异响应不灵敏。以土茯苓色谱指纹图谱数据为实例证实了当两样本数据间比例相差较大时,夹角余弦相似度对共有峰和非共有峰响应的灵敏程度相差很大。组合相似度在共有峰的夹角余弦相似度基础上纳入了非共有峰的影响,分别计算非共有峰和共有峰对相似度的贡献,并以最大峰比例同态性为指标,确定非共有峰的合适权重。基于样本峰面积数据建立的组合相似度模型能灵敏地反映待测样本与参照样本内在成分的峰比例变化,适合衡量多个药材样本间的相似程度,已成为评价药材质量相似度的新方法。 相似文献
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The performance of a classification model is often assessed in terms of how well it separates a set of known observations into appropriate classes. If the validation sets used for such analyses are redundant due to bias in sampling, the relevance of the conclusions drawn to prospective work in which new kinds of positives are sought may be compromised. In the case of the various virtual screening techniques used in modern drug discovery, such bias generally appears as over‐representation of particular structural subclasses in the test set. We show how clustering by substructural similarity, followed by applying arithmetic and harmonic weighting schemes to receiver operating characteristic (ROC) curves, can be used to identify validation sets that are biased due to such redundancies. This can be accomplished qualitatively by direct examination or quantitatively by comparing the areas under the respective linear or semilog curves (AUCs or pAUCs). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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《Journal of separation science》2017,40(6):1244-1253
The composition of traditional Chinese medicine is extremely complex, so it is difficult to ensure quality consistency. We took Compound Danshen Tablets as the object of the study, by using high‐performance liquid chromatography to establish multiwavelength fusion fingerprints. Characteristic fingerprints of 30 batches of samples were generated at four wavelengths and evaluated by systematic quantified fingerprint method. An on‐line antioxidant determination method was used for the determination of the antioxidant components in Compound Danshen Tablets. The fingerprint analysis of the marker compounds can reflect the content of the marker compounds, which were determined by using the external standard method. This study elucidated that multiwavelength fusion fingerprint profiles and multiple markers compound analysis in conjunction with the assay of antioxidant activity offered a reliable and efficient approach to quantitatively evaluate the quality consistency of the traditional Chinese medicine and herbal preparations. 相似文献
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用高效液相色谱组方指纹图谱智能预测中药质量的新模式 总被引:1,自引:0,他引:1
建立大黄、黄芩、黄连的高效液相色谱(HPLC)组方指纹图谱,确定其融合模型,观察组方融合指纹图谱(CSF)与一清片复方样品指纹图谱的一致性,从而以CSF代替复方整体来智能预测复方制剂质量。用二极管阵列检测器(DAD)同时测定黄芩、大黄、黄连和一清片在268 nm波长下的HPLC指纹图谱,并使用系统指纹定量法进行定性、定量评价。结果 CSF涵盖各单味药主要色谱峰信息,即CSF共有峰(55个)涵盖一清片样品共有峰(50个)的主要指纹图谱信息。15批样品的质量除YQT-S01为5级外,其他质量均为3级及以上。各组合模式CSF质量除CSF-2为6级外,其余均为2级或1级。该文探讨了标准指纹图谱和中药组方融合指纹图谱的相关性,可以与相应的计算机评价软件相结合,通过组方融合指纹图谱所代表复方制剂的整体指纹图谱来实现智能预测中药成方制剂质量的新模式。 相似文献
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指纹显现技术是痕迹学乃至物证技术学领域研究的重点内容之一,现行的指纹显现试剂和显现方法仍存在一定的隐患。以稀土荧光粉Zn2Si O4:Mn2+,Er3+为研究对象,借助纳米稀土发光材料在生物荧光检测领域的应用思路,通过表面修饰技术、湿法球磨等方法对荧光粉的发光性能、吸附能力和粒径形貌等指标进行优化与控制,使之成功地应用于潜在指纹显现中,能够显现遗留在不同客体上不同遗留时间的潜在指纹;建立了一种高效、无毒、无损、便利的潜在指纹显现技术新方法,并拓展了稀土荧光粉的应用范围。 相似文献
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基于~1H NMR指纹图谱结合多变量分析的地沟油检测方法 总被引:1,自引:0,他引:1
地沟油事件是中国近期发生的严重食品安全事故,而针对地沟油的检测目前尚无非常有效的方法报道.本研究对60种市售植物油和地沟油样品分别进行了核磁H谱测定,建立了12个鉴别指标,采用聚类分析技术对样品进行聚类分析,并将样品分为8大类,建立了判别函数.将未知样品的1H NMR数据代入判别函数,可检测和判别未知油的来源和品质.将该方法应用于两次盲测共69个样品,结果显示,两次盲测的正确率分别为91.9%和93.8%,可作为食用油品质检测的重要参考. 相似文献
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Gargey B. Yagnik Andrew R. Korte Young Jin Lee 《Journal of mass spectrometry : JMS》2013,48(1):100-104
We have previously developed in‐parallel data acquisition of orbitrap mass spectrometry (MS) and ion trap MS and/or MS/MS scans for matrix‐assisted laser desorption/ionization MS imaging (MSI) to obtain rich chemical information in less data acquisition time. In the present study, we demonstrate a novel application of this multiplex MSI methodology for latent fingerprints. In a single imaging experiment, we could obtain chemical images of various endogenous and exogenous compounds, along with simultaneous MS/MS images of a few selected compounds. This work confirms the usefulness of multiplex MSI to explore chemical markers when the sample specimen is very limited. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Chung-Shin Yuan Chun-Xing Hai Ming Zhao 《中国颗粒学报》2006,4(6):304-311
Fingerprints and source profiles of fine and coarse sands that originate from Central Inner Mongolia during Asian continental sandstorms (ACS) can be used to identify the odgin of Asian sands and to trace them as they travel downwind. Soil samples collected at various land surfaces in Central Inner Mongolia were resuspended using a dry powder atomizer in an enclosure chamber. The resuspended sands were then sampled by two dichotomous samplers situated at the bottom of the enclosure chamber for fine (PM2 5) and coarse (PM2.5-10) sands, respectively. The chemical composition of sands, including water-soluble ionic species, metallic contents, and carbonaceous contents, were further analyzed. Results from resuspension tests indicated that the soils contained considerably more coarse particles than fine Moreover, Mg, K, Al, and Fe in coarse sand had strong correlations with each other. The ratio of Mg, K. Fe (or Al) to Al (or Fe) and OC/EC in the coarse sands can be used as the fingerprints of Asian sands originating from Central Inner Mongolia. 相似文献