Rawson R B, Starich G H, Rawson R D
University of New Mexico, Department of Surgery, Albuquerque, NM, USA.
J Forensic Sci. 2000 Sep;45(5):1023-7.
The forensic investigator is frequently confronted with cases that present with wounds and blunt force trauma. Presently, the forensic investigator depends upon previous experience and further investigative deduction of the crime scene to analyze these injuries. Although not readily apparent to the naked eye, many skin tissue injuries can be visualized with scanning electron microscopy (SEM). This study was designed to establish skin trauma resolution using SEM in various skin preparations. Tissue trauma was induced on leather, preserved skin, fresh skin, and living skin using dies of varying thread size. Calibrated pressure forces in pounds per square inch (psi) were applied and impressions made using vinyl polysiloxane. Positive replicas of the tissues were prepared for SEM using isocyanate resin. After sputter coating the cast with 35 nm of gold-palladium, electron micrographs were generated using a Jeol JSM-5310LV scanning electron microscope. To establish resolution, thread widths of 52, 104, and 208 threads per inch (tpi) and trauma forces of 150, 200, and 250 psi were used to produce the impressions. Microgrooves that were identified on the die threads were analyzed. The optimum pressure for resolution studies was 150 psi using the 52 tpi die on the leather sample (4.67 +/- 0.88 microm, p = 0.046 and 0.025, respectively, by ANOVA). The resolution was compared to that of leather using preserved, fresh, and living skin. The resolution in preserved and fresh skin was less than for leather (9.00 +/- 1.73 and 10.5 +/- 4.5 versus 4.67 +/- 0.88 microm, p = 0.09 and p = 0.20, respectively). Living skin resolution was 3 microm at 52 tpi and 100 psi. Various implements of blunt force trauma were also examined using the leather sample. Time after trauma resolution was examined at 0 (3 microm), 5 (6 microm), 10 (8 microm), and 20 (9 microm) min in living tissue. A comparison between the microgrooves on the die replicas and the tissue trauma impressions revealed striking agreement for both linearity and resolution. Analysis of the microgrooves suggests that discrete morphological characteristics are seen in skin tissue traumas. This method could expand the tools available for the forensic investigation of blunt force trauma.
法医调查人员经常会遇到涉及伤口和钝器伤的案件。目前，法医调查人员依靠以往经验以及对犯罪现场的进一步调查推理来分析这些损伤。虽然许多皮肤组织损伤肉眼不易察觉，但通过扫描电子显微镜（SEM）可以观察到。本研究旨在利用SEM在各种皮肤样本制备中确定皮肤创伤分辨率。使用不同线径的模具在皮革、保存皮肤、新鲜皮肤和活体皮肤上造成组织创伤。施加以每平方英寸磅数（psi）为单位的校准压力，并使用乙烯基聚硅氧烷制作压痕。使用异氰酸酯树脂为SEM制备组织的正性复制品。在用35纳米的金钯对铸型进行溅射镀膜后，使用Jeol JSM - 5310LV扫描电子显微镜生成电子显微照片。为确定分辨率，使用每英寸52、104和208线（tpi）的线宽以及150、200和250 psi的创伤力来制作压痕。对模具螺纹上识别出的微槽进行分析。在皮革样本上使用52 tpi模具进行分辨率研究的最佳压力为150 psi（通过方差分析，分别为4.67±0.88微米，p = 0.046和0.025）。将保存皮肤、新鲜皮肤和活体皮肤的分辨率与皮革的分辨率进行比较。保存皮肤和新鲜皮肤的分辨率低于皮革（分别为9.00±1.73和10.5±4.5与4.67±0.88微米，p = 0.09和p = 0.20）。活体皮肤在52 tpi和100 psi时的分辨率为3微米。还使用皮革样本检查了各种钝器伤工具。在活体组织中，分别在创伤后0（3微米）、5（6微米）、10（8微米）和20（9微米）分钟检查创伤分辨率。模具复制品上的微槽与组织创伤压痕之间的比较显示，在线性和分辨率方面都有显著的一致性。对微槽的分析表明，在皮肤组织创伤中可以看到离散的形态特征。这种方法可以扩展用于钝器伤法医调查的工具。
