Accuracy and precision of a laser-spectroscopy approach to the analysis of δ2H and δ18O in human urine

The isotope ratio analysis of body water often involves large sample numbers and lengthy sample processing. Here we demonstrate the ability of isotope ratio infrared spectroscopy (IRIS) to rapidly and accurately analyse the isotope ratios of water in urine. We analysed water extracted from human urine using traditional isotope ratio mass spectrometry (IRMS) and compared those values with IRIS-analysed extracted water and un-extracted urine. Regression analyses for δ²H and δ¹⁸O values between (1) extracted water analysed via IRMS and IRIS and (2) urine and extracted water analysed via IRIS were significant (R ²=0.99). These results indicate that cryogenic distillation of urine was not required for an accurate estimate of the isotopic composition of urine when using IRIS.     

Methodik und Anwendung des Radioimmunoassays

1. Einleitung

2. Tracerdarstellung

3. Geuinnung von Antiseren

4. Methoden zur Trennung von freier und antikörpergebundener Radioaktivität

5. Analysengang

6. Spezifität

7. Empfindlichkeit

8. Anwendungsbeispiele

9. Literatur     

Direct Radioimmunoassay of Proinsulin and Insulin in Human Plasma by Chromatographic Technique

Specific method for direct radioimmunoassay of IRP and IRI separately in human plasma has been described. The method is used for extraction of total insulin and separation of IRP from IRI by paper chromatography to be assayed separately. The separation of the two components are indentified and confirmed by column chromatography, paper chromatography and U.V. spectral analysis in comparison with the standard compounds.

134 plasma samples of different cases were, investigated for determination of IRI, IRP and IRT, of which 39 normals, 16 normal obes, 21 juvinil diabetes, 18 adult oncet diabetes, 10 recent adult diabetes, 12 hypothroid and 18 bilharzial hepatosplenomegaly to evaluate the levels of the test in comparison with blood sugar concentration.     

Modified Preparation of 99mTe-Iron Hydroxide Macroaggregate (99mTe-Fe-(OH)2MA)

A modified method for preparing ^99mTc-FHMA for pulmonary studies is elabrated. It includes a new antioxidant sodium metabisulphite. The optimum conditions for the reparation are given. A simple and rapid procedure with a yield more than 98% is described which eliminates a further purification step.     

An Overview of Infrared Spectroscopy Based on Continuous Wavelet Transform Combined with Machine Learning Algorithms: Application to Chinese Medicines,Plant Classification,and Cancer Diagnosis

Abstract

Infrared spectroscopy has been a workhorse technique for materials analysis and can result in positively identifying many different types of material. In recent years there have been reports using wavelet analysis and machine learning algorithms to extract features of Fourier transform infrared spectrometry (FTIR). The machine learning algorithms contain back-propagation neural network (BPNN), radial basis function neural network (RBFNN), and support vector machine (SVM). This article reviews the important advances in FTIR analysis employing a continuous wavelet transform (CWT) and machine learning algorithms, especially in the applications of the method for Chinese medicine identification, plant classification, and cancer diagnosis.     

卷积神经网络用于近红外光谱古筝面板木材分级

目前,我国乐器制作行业在古筝面板用木材等级的筛选上主要依赖于技师主观评判,但此法缺少科学理论的依据,效率低,客观性及出材率的提高等方面受到限制,无法满足乐器市场的大量需求。实现古筝面板用木材快速、智能化的分级工作是一个急需解决的课题。近红外光谱非常适用于测量含氢的有机物质。古筝面板木材主要化学成分的化学键均由含氢基团组成,不同等级板材的化学成分存在差异,这些差异反映在近红外光谱中,为判断木材等级提供了可能。同时卷积神经网络对非线性数据具有较强的特征提取能力,所以提出一种应用卷积神经网络模型对光谱数据进行分析的方法,进而判别木材的等级。应用了Savitzky Golay一阶、二阶微分两种预处理方法和核主成分分析、连续投影算法两种数据压缩方法,通过所设计的卷积神经网络模型以样本识别准确率和模型构建过程中的损失值作为判定指标选出最佳预处理和数据压缩方法。为了提高模型提取分析光谱数据的能力和避免过拟合现象,应用了多通道卷积核、批量归一化和early stopping策略,将通过两层卷积层提取的特征信息送入全连接层,从而充分提取剩余信息,通过Softmax函数获得板材的最终预测等级,从而确定了最终模型。最终Savitzky Golay一阶微分和核主成分分析为最佳数据处理方法,同时得出用于区分不同等级的古筝面板用木材的主要关键谱带,分别为1 163~1 243, 1 346~1 375和1 525~1 584 nm。将该模型应用于测试集样本,古筝面板用木材的等级识别准确率为95.5%。实验结果表明所提出的方法可以高效地处理光谱数据,有效识别区分不同等级的古筝面板用木材的关键特征,从而为广阔的乐器市场提供一定的技术支持。     

合成氨催化剂研究的新进展

 近20多年来,随着英国BP公司钌基催化剂的发明和我国亚铁基熔铁催化剂体系的创立,标志着合成氨催化剂进入了一个新的发展时期,由唯一的传统Fe3O4路线发展为三条技术路线,并各自取得了重大进展．本文扼要介绍了Fe3O4基传统催化剂和钌基催化剂的主要研究成果和发展趋势,着重综述了我国独创的Fe1－xO基熔铁催化剂的发现及其高活性机理探讨方面的研究成果．回顾了20世纪合成氨工业及其催化剂从创立、发展,到取得辉煌成就的历程,展望了21世纪的发展趋势．     

中药柴胡中K、Ca、Zn、Fe和Mn含量测定及清除自由基机制分析

研究了柴胡中金属元素的作用为治疗呼吸系统疾病提供依据.选取柴胡粉碎、干燥至恒重,采用HNO3-HClO4湿法消化,用原子吸收分光光度计测定宏量元素钙、钾和微量元素铁、锰、锌的含量.测定结果表明,柴胡中含有丰富的金属元素.用原子吸收分光光度法测定中草药中金属元素含量,方便迅速.结果准确,测定结果为临床上合理利用柴胡清除自由基、预防和治疗呼吸系统疾病提供科学依据,也为大力开发、利用中药柴胡提供了有用的数据.     

基于MATLAB的静电场模拟

在静电场中引入电位和电场强度后,通过等电位线图和场强分布图可以具体的描述静电场这种抽象的物质场。传统的静电场模拟实验直观地展现出了静电场的分布从而形象地描述了静电场,由于这种方法属于类比模拟,所以存在一定的缺陷(比如不直接,不能描述立体规律等等)。随着计算机技术的发展,利用计算机技术来模拟静电场等物质场逐渐成为趋势。通过借鉴大量资料简要地介绍了如何利用计算机模拟静电场,如何利用MATLAB软件模拟静电场的问题。