基于紫外可见反射光谱法对染色头发的初步研究

紫外可见反射光谱法是一种快速无损检验的方法,本文从采样量、样品的固定等方面对染色头发进行紫外可见光谱检验方法进行了初步探索,使用紫外可见光谱仪的积分球附件可以对不同染发剂染色头发进行大致的分类鉴别。     

毒品与毛发的结合及其影响因素

毛发毒品的分析在毒品检验中具有独特优势,而毛发与毒品的结合状况及毒品聚集于毛发的机制影响其检测的准确性和灵敏性。对毒品与毛发的结合位点、毒品与毛发结合的差异性因素以及外界因素对毒品与毛发结合的影响进行了综述。     

Medicalisation,pharmaceutical promotion and the Internet: a critical multimodal discourse analysis of hair loss websites

This study conducts a critical multimodal discourse analysis of commercial hair loss websites. Specifically, I focus on eight sites which provide information about and promote the pharmaceutical hair loss treatment Propecia, a widely available medication marketed to treat male pattern baldness. I identify four salient discursive strategies through which the websites depict male hair loss and the Propecia treatment, namely (1) representing the balding man as type and outcast, (2) promoting the attractiveness and self-assurance of the hirsute man, (3) situating male hair loss in a scientific discourse and (4) encouraging consumers to self-evaluate their hair loss. By inducing insecurities in men experiencing hair loss and encouraging them to embrace pharmaceutical remedies as a viable response to male pattern balding, these discursive-semiotic strategies help to reproduce the contemporary sociocultural practice of medicalisation, the phenomenon whereby the natural processes of life are treated as medical problems. The findings of this study suggest that these promotional discourses play a role in transforming ordinary, benign ailments into illnesses, reconfiguring them as treatable disorders for commercial gain.     

Rapid presumptive "fingerprinting" of body fluids and materials by ATR FT-IR spectroscopy

Human body fluids and materials were evaluated using attenuated total reflectance Fourier transform infrared spectroscopy. Purified proteins, cosmetics, and foodstuffs were also assayed with the method. The results of this study show that the sampled fluids and materials vary in the fingerprint region and locations of the amide I peaks because of the secondary structure of the composite proteins although the C = O stretch is always present. The distinct 1016 cm(-1) peak serves as a signature for semen. The lipid-containing materials (e.g., fingerprints, earwax, tears, and skin) can also be easily separated from the aqueous materials because of the strong CH(3) asymmetric stretch of the former. Blood-saliva and blood-urine mixtures were also successfully differentiated using combinations of peaks. Crime scene investigators employing rapid, portable, or handheld infrared spectroscopic instruments may be able to reduce their need for invasive, destructive, and consumptive presumptive test reagents in evaluating trace evidence.     

Forensic Discrimination of Dyed Hair Color: II. Multivariate Statistical Analysis*,†

Abstract: This research is intended to assess the ability of UV–visible microspectrophotometry to successfully discriminate the color of dyed hair. Fifty‐five red hair dyes were analyzed and evaluated using multivariate statistical techniques including agglomerative hierarchical clustering (AHC), principal component analysis (PCA), and discriminant analysis (DA). The spectra were grouped into three classes, which were visually consistent with different shades of red. A two‐dimensional PCA observations plot was constructed, describing 78.6% of the overall variance. The wavelength regions associated with the absorbance of hair and dye were highly correlated. Principal components were selected to represent 95% of the overall variance for analysis with DA. A classification accuracy of 89% was observed for the comprehensive dye set, while external validation using 20 of the dyes resulted in a prediction accuracy of 75%. Significant color loss from successive washing of hair samples was estimated to occur within 3 weeks of dye application.     

Accumulation of explosives in hair--Part 3: Binding site study

This study extends previous work on the sorption of explosives to the hair matrix. Specifically, we have studied the interaction of 2,4,6-trinitrotoluene (TNT) and triacetone triperoxide (TATP) as a function of chemical pretreatment with acetonitrile, neutral and alkaline hydrogen peroxide, methanolic KOH and potassium permanganate, and the morphological changes that accompany these treatments. While differences in vapor pressure can account for quantitative differences between TNT and TATP sorption, both are markedly affected by the chemical rinses. Examination of the hair surface shows different degrees of smoothening following rinsing, suggesting that the attachment to hair is largely a surface phenomenon involving the 18-methyleicosanoic acid lipid layer. Density functional theory calculations were employed to explore possible nucleation sites of TATP microcrystals on the hair. We conclude that some of the sites on melanin granular surfaces may support nucleation of TATP microcrystals. Moreover, the calculations support the experimental finding that dark hair adsorbs explosives better than light hair.     

Development of a Protein‐based Human Identification Capability from a Single Hair

Shed human hair (lacking root nuclear DNA) frequently contributes important information to forensic investigations involving human identification. Detection of genetic variation observed in amino acid sequences of hair proteins provides a new suite of identity markers that augment microscopic hair analysis and mitochondrial DNA sequencing. In this study, a new method that completely dissolves single hairs using a combination of heat, ultrasonication, and surfactants was developed. Dissolved proteins were digested and genetically variant peptide (GVP) profiles were obtained for single hairs (25 mm) via high‐resolution nanoflow liquid chromatography‐based mass spectrometry and a novel exome‐driven bioinformatic approach. Overall, 6519 unique peptides were identified and a total of 57 GVPs were confirmed. Random match probabilities ranged between 2.6 × 10^?2 and 6.0 × 10^?9. The new bioinformatic strategy and ability to analyze GVPs in forensically relevant samples sizes demonstrate applicability of this approach to distinguish individuals in forensic contexts.     

甲基苯丙胺在豚鼠毛发中分布及转化的初步研究

目的对甲基苯丙胺在豚鼠毛发中分布及转化机制进行初步研究。方法利用GC/MS,GC/NPD法,测定单次及多次给药豚鼠毛发中MAP、AP的含量变化过程,考察给药剂量与毛发中MAP、AP的含量间的关系,并研究毛发颜色对染毒豚鼠毛发中MAP、AP含量的影响。结果单次及多次给药豚鼠毛发中代谢产物AP均高于原体MAP,给药时间及给药剂量与毛发中MAP、AP的含量显著相关,同体豚鼠黑色毛发中的MAP、AP含量均明显高于棕色、白色毛发。结论给药方式、给药剂量及毛发颜色对豚鼠毛发中MAP、AP的含量均有显著影响。     

Investigating Residential History Using Stable Hydrogen and Oxygen Isotopes of Human Hair and Drinking Water

The relationship between isotopic signals in human hair and geographic region has potential forensic applications for identifying unknown individuals' place of recent residence. This study analyzes δ²H and δ¹⁸O isotopes in residential tap water and bulk hair samples from 17 volunteers representing 12 locations in Ontario, Canada. There is a strong correlation (R² = 0.9) between δ²H and δ¹⁸O values of the water samples. In contrast, the δ²H and δ¹⁸O values of the hair samples are weakly correlated (R² = 0.3), and the greater variability in the data is linked to dietary factors. This study demonstrates that the δ²H and δ¹⁸O values of hair and drinking water can be used to help identify potential place of residence in forensic cases, particularly in relation to proximity to large bodies of water such as the Great Lakes, but interpretations are complicated by the contribution of both water and diet to δ²H and δ¹⁸O values in hair.