Physical forms of contemporary small-arms propellants and their forensic value

Intermediate gunshot wounds typically produce powder tattooing and/or stippling of the skin. The size and density of such powder-induced injuries around an entry wound are used to estimate the separation distance between the muzzle of the responsible firearm and the entry site through test firings at selected muzzle-to-target distances, with ammunition comparable to the injury-producing round and the evidence firearm. The foregoing is well known to forensic pathologists who document and describe such powder patterns in gunshot victims and firearm examiners who customarily produce the test-fired powder patterns for subsequent range-of-fire determinations. Less known, particularly to pathologists, is the considerable variety in forms of modern nitrocellulose propellants, their effects on powder-induced injuries to human skin, and the value of these varied physical forms in the reconstruction of shooting incidents. These factors are the subject of this article.     

Application of fluorescence lifetime imaging (FLIM) in latent finger mark detection

Fluorescence lifetime imaging (FLIM) in frequency domain enables the mapping of the spatial distribution of fluorescence lifetimes of a specimen. It has been extensively applied in biology. In this paper, a theoretical analysis for the fluorescence lifetime determination of latent finger mark samples is described, which is followed by the feasibility study of using FLIM in frequency domain for latent finger marks detection. Preliminary experiments are carried out with latent finger marks treated with a fluorescent powder on two different substrates. The resulting fluorescence lifetime image of finger mark revealed a good contrast, and was able to detect the latent finger marks clearly.     

A novel method for STR-based DNA profiling using microarrays

We describe a novel method for rapidly identifying and distinguishing between different DNA sequences using short tandem repeat (STR) analysis and DNA microarrays. The method can be used to deduce identity, length, and number of STRs of the target molecule. We refer to this technique as the "variable-length probe array" method for STR profiling (VLPA). The method involves hybridization of the unknown STR target sequence to a DNA microarray displaying complementary probes that vary in length to cover the range of possible STRs. A post-hybridization enzymatic digestion of the DNA hybrids is then used to selectively remove labeled single-stranded regions of DNA from the microarray surface. The number of repeats in the unknown target is then deduced based on the pattern of target DNA that remains hybridized to the array. This DNA profiling technique is useful for performing forensic analysis to uniquely identify individual humans or other species.     

HRP标记探针MVR分型法在法医学上的应用

采用辣根酶标记寡核管酸探针数字编码小卫星MS可变重复序列（HRP标记探针MVR方法）,检验微量生物材料。结果表明,相当于5μl血液的血痕、单根有毛囊的毛发以及相当于4μl唾液的斑迹均获得了清晰易读的MVR图谱,灵敏度达1ng。将此方法应用于检案实践取得了较好的效果。MVR－PCR技术在法医学个人识别和亲子鉴定方面极有应用前景。     

The history of heroin abuse by assaying 6-monoacetylmorphine and morphine in human hair

The purpose of this study is to conclude the history of heroin abuse by assaying 6-monoacetylmorphine (MAM) and morphine (MOR) in human hair. The hair of heroin abuse was labeled and segmented, then washed and cut into fragments. After hydrolyses and extraction, 6-MAM and MOR in human hair were determined by GC/MS-SIM with selected ion monitoring. Results of the segmented hair were analyzed. It provided useful information about the history of heroin abuse (hair growth rate 1-1.5 cm/mon).