The risk of detection

The clearance rate is often used as an indicator of the risk of detection, in spite of the fact that these are different matters. This article suggests a method to make estimates of the risk of detection based on information from the Swedish crime statistics. The risk of detection is expressed as a function of the dark figure. Empirical estimates of the risk are given for drunken driving, residential burglary, and assault between strangers. These estimates are followed up with some calculations concerning the impact of crime activity level on the risk of getting caught. One major conclusion of the findings is that the risk of detection varies very moderately with the dark figure. This means that if there is some knowledge of the dark figure, it is often possible to make fairly good estimates of the risk of detection.     

The detection of simulated amnesia

Claims of amnesia are frequently raised in criminal and civil cases. There is a consensus in the legal community that amnesia is easily faked and practically impossible to disprove, and that many who claim to be amnesic are malingering. The present studies compared, on a variety of memory tasks, subjects instructed to simulate amnesia with subjects who had memory impairments due to brain damage. The simulators displayed patterns of performance different from those of memory-impaired subjects. These results suggest that lay-people have inaccurate beliefs about the cognitive features of amnesia, and do not distinguish among etiologically distinct amnestic disorders. Tasks that exploit lay-people's inaccurate beliefs about amnesia appear promising for the detection of malingering.     

唾液检材在毒品检测中的应用

近年来,毒品滥用问题日益突出,提高生物样品中毒品检测技术的性能是法庭毒物学研究的重点。相比于血液和尿液样品,唾液在的样品采集和毒品检测中具有诸多优势,因而逐渐受到重视。本文对近年来国内外唾液样本用于毒品检测方面的研究成果进行综述,介绍唾液毒品检测的发展情况以及相关的代谢动力学研究状况,旨在为相关研究和实践提供参考。     

The effect of heating on Y-chromosome detection

The effect of heating on Y-chromosome detection was investigated. Heat-treated blood was divided into four groups according to the hemolysis pattern obtained by the coil planet centrifuge system. A significant difference between the Y-positive nuclei of males and females was observed up to group III of the hemolysis pattern, and it was possible to determine the sex of the blood donor in spite of karyolysis and degeneration of blood components. However, sex determination of blood in group IV, indicating complete hemolysis, was impossible because of overlapping between male and female Y-chromosome counts. Practical application of this sex determination method was successful even with severly burned cadavers. However, it was suggested that putrefaction together with heat damage made the identification nearly impossible.     

The detection of psilocin in human urine

Pharmacokinetic studies of psilocybin in humans have shown the rapid dephosphorylation of psilocybin to psilocin with further conversion to 4-hydroxy-tryptophole (4HT) and 4-hydroxyindole-3-acetic acid (4HIAA) in plasma. Our study shows that psilocin also undergoes conjugation and can be found in the urine as the psilocin-glucuronide conjugate. Recoveries after enzymatic hydrolysis of the urine with beta-glucuronidase (Helix Pomatia or E. Coli) when compared to non-hydrolyzed urine confirmed the presence of the glucuronide. Detection of psilocin from hydrolyzed and extracted samples was optimized for GC/MS by derivatization with MSTFA. The method developed allows for the detection of psilocin in urine with a limit of quantitation of 10 ng/mL, based on 5 mL of spiked urine. Using this method, our laboratory has confirmed the presence of psilocin in 6 out of 8 urine samples, with concentrations ranging from 10 ng/mL to greater than 200 ng/mL. Before implementation of the hydrolysis and derivatization steps, our limit of detection was 200 ng/mL, based on spiked urine standards. No case samples were positive without hydrolysis and derivatization.     

The detection of nifedipine in biological materials

The objective of the present study was to find optimal conditions for the isolation of nifedipine from biological materials by ethylacetate. It was shown that nifedipine can be purified from co-extracted substances of the biological material on a Silasorb C-18 column with the size of the particles 30 microns. The authors propose to use thin-layer chromatography, IR spectrophotometry, and reverse-phase high performance liquid chromatography for the identification and quantitative determination of nifedipine extracted from cadaveric liver samples.     

百草枯中毒分析检测方法的研究进展

本文介绍了最近20年来国内外有关生物检材中百草枯的提取、净化及定性定量分析检测方法的研究进展,从而为进一步研究百草枯中毒的分析检验方法提供参考。     

The detection of HIV antibodies in blood stains

Blood samples were collected on cotton wool and stored at +20 degrees C. These samples were tested in an enzyme linked immunosorbent assay and the immunoblotting test. HIV-antibodies could be detected in samples stored up to four month.     

The detection of Y chromosomes in bloodstains--a reevaluation

A method has been described for detecting Y chromosomes in the leukocytes of human bloodstains prepared on a variety of substrates. The factors that influence the proportion of chromosomes exhibiting a Y spot (the Y cell index) in a bloodstain are considered, including the subjective nature of assessment of the Y chromosome fluorescence, the substrate, and the age of bloodstain. In contrast to previous workers no decay in Y cell index with the age of the stain was observed. The results of a blind trial involving stains derived from case work, where from other evidence there was no doubt as to the sex of the donor, are presented. Sixty-five percent of the male bloodstains were correctly identified and no females were wrongly reported as male.     

The detection of group-specific component from urine samples

The detection of group-specific component (Gc) from serum and bloodstains has been widely used in the forensic laboratory. A recent increase in substituted or adulterated urine samples in various drug screening programs has necessitated methods to determine the donor. This paper discusses the detection of Gc from urine samples. The samples were concentrated and applied to ultrathin polyacrylamide gel and focused for 150 min. This method separates the samples into the three common phenotypes found in all human populations. A nitrocellulose membrane blotting technique was used to detect the Gc bands. Serum and urine samples were collected from each individual and were typed for Gc. Urine samples tested after 6 months of storage (4 degrees C) were still readable. This method provides the forensic laboratory with an additional test from a body fluid which, until recently, provided little information.     

The role of forensic geoscience in wildlife crime detection

The increase in both automation and precision in the analysis of geological materials has had significant impact upon forensic investigations in the last 10 years. There is however, a fundamental philosophical difference between forensic and geological enquiry. This paper presents the results of forensic geoscientific investigations of three cases of wildlife crime. Two cases involve the analysis of soils recovered after incidents of illegal badger baiting in the United Kingdom. The third case involves the illegal importation of Eleonora's Falcon (Falco eleonorae) into the United Kingdom from the Mediterranean. All three cases utilise the analysis of soils by a variety of physical, chemical and biological techniques. These involve mineral and grain size analyses, cation and anion compositions, pH, organic content and pollen analysis. The independent analysis undertaken by specialists in each of these three main fields conclude firstly, that there is a significant similarity between sediments taken at the crime site at both badger setts and with sediments recovered from various spades, shovels and clothing belonging to suspects and secondly, that the soils analysed associated with the removal of the falcon eggs in the Mediterranean contained characteristics similar in many respects to the soils of the breeding areas of F. eleonorae on the cliffs of Mallorca. The use of these independent techniques in wildlife crime detection has great potential given the ubiquitous nature of soils and sediments found in association with wildlife sites.     

应用红外化学成像技术显现潜在的指印

目的应用红外化学（光谱）成像技术显现潜在指纹。方法采用这种新技术进行显现潜在指印的初步实验。结果显示了其对复杂图案背景上指印突出的显现能力。该成像技术具有物质形态特征检验和物质成分检验双重分析能力，在法庭科学领域具有重要的应用价值。     

The role of deception in P300 memory detection

Purpose. P300 memory detection test is a neuroscientific procedure to assess memories stored in the brain. P300 memory detection can and is currently applied to assess criminal suspects on recognition of critical crime information. Contrasting memory detection with lie detection, researchers have argued that P300 memory detection does not involve deception. We empirically investigated this argument by manipulating deception between groups. Methods. Thirty‐four community volunteers participated in a P300 memory detection test, answering either deceptively (deceptive condition) or truthfully (truth condition) to their own name. Results. P300 memory detection was significant in the truth condition, indicating that deceptive responding is not a prerequisite for valid P300 memory detection. However, there were clear indications that deceptive responding improved memory detection. Conclusions. Deception seems involved in the P300 memory detection test; and deceptive responding may add to test accuracy.     

The detection of amizil in studying different objects]

Amisyl possesses toxic effect and it may become an object of forensic chemical laboratory analysis. Reactions of staining with reagents Marki, Frede and sulphuric acid as well as with reagent Dragendorf-orange residue--were used for amisyl identification. Method of amisyl detection in sorbent thin layer and identification by maximum light absorption in 258 nm area was also suggested. Usefulness of methods developed for amisyl analysis during investigation of pharmacological substances and human urine was studied.