A discrimination method for paper by Fourier transform and cross correlation

A non-destructive method for discriminating between different types of paper has been proposed, using image analysis, Fourier transformation, and cross-correlation matching. A fast Fourier transform (FFT) is used to extract the periodicity in the structure of paper that results from the manufacturing processes. The light-transmission images of the paper to be Fourier transformed are obtained from a flatbed image scanner. The similarity between the power spectrum of the FFT of the sample and that of a reference is quantified using a cross-correlation matching method. An advantage of using frequency analysis is that periodicity can be detected even if the sample is damaged or is printed on. The technique works on samples as small as 2 cm2.     

Forensic DNA Analysis of Wheat Flour as Commonly Used in White Powder Cases

In the wake of terrorist attacks using anthrax and ricin, white powder is often encountered in cases of malicious mischief and terrorist threats. Wheat flour is a common white powder encountered in such criminal investigations. We used DNA analysis to investigate wheat flour samples for identification and discrimination as trace evidence. Species identification of commercially available wheat flour was carried out by sequencing a partial region of the ribulose bisphosphate carboxylase large subunit gene (rbcL). Samples were discriminated using short tandem repeat (STR) analysis. The rbcL sequences of all wheat flour samples were identical and showed a high level of similarity to known wheat (Triticum aestivum L.) sequences. Furthermore, flours had characteristic patterns in STR analyses, with specific cultivars showing distinctive patterns. These results suggested that the identification of wheat flour species is possible using rbcL sequencing, and that STR analysis is useful for discriminating between samples.     

IN SEARCH OF A WORKABLE DIVISION OF LABOR BETWEEN NATIONAL AND INTERNATIONAL CRIMINAL JURISDICTIONS

This article deals with the question of the universal application of law from the perspective of necessary division of labor between national and international criminal jurisdictions. Applying international criminal justice fairly enhances its legitimacy, and international criminal law’s procedural aspects also must be fair. The universal application of international criminal law in multiple forums seems to be ensured by means of the proper division of labor between national and international criminal jurisdictions. Recent arguments show that this division of labor between national and international criminal jurisdictions may be properly handled in accordance with seniority criterion, which is the “big fish” versus “small fry” distinction. Lately, the international community has recognized seniority criterion as prosecutorial policy and a jurisdictional threshold, although in a different context, which is at a domestic level when that community tackles with the Somali pirates. The article argues that prosecuting both “big fish” and “small fry” is important for the universal application of international criminal law. In order to achieve this goal and to combat impunity, the feasible division of labor would be pursued with reference to the “big fish” versus “small fry” distinction.     

Simultaneous determination of eight catechins and four theaflavins in bottled tea by liquid chromatography-tandem mass spectrometry for forensic analysis

Tea, and particularly bottled tea, is widely consumed worldwide and is often encountered at crime scenes in poisoning cases or used in place of urine in drug abuse monitoring. Tea is a rich source of polyphenols, such as catechins and theaflavins, and these compounds are useful for identification of trace quantities of tea samples. However, information on the contents of catechins and theaflavins in bottled tea is limited. In this study, a method was developed for simultaneous analysis of eight catechins and four theaflavins in tea using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of these polyphenols were determined in bottled black, oolong, and green teas after a simple pretreatment process by the standard addition method. The developed LC-MS/MS method was rapid and all tested polyphenol compounds were separated within ~14 min. All tea types contained all the catechins, at varying concentrations, but not all the theaflavins were present in all the tea types. This indicates that the theaflavin composition reflects the degree of the fermentation and could be used for discrimination among different types of tea. All the green tea samples contained all eight catechins; however, the concentrations of these compounds varied among the tea samples. Principal component analysis and hierarchical cluster analysis were useful for discrimination of samples. It has been unclear whether the variations of chemical components are useful for forensic discrimination. Our results demonstrate that, in addition to identification of tea varieties, catechins and theaflavins can be used for the discrimination of bottled tea samples.