Scanning electron microscope study of the lung in drowning

The authors describe the results obtained using the scanning electron microscope (SEM) to study drowned lungs and control lungs. Results are compared with a previous study carried out using laboratory animals. The results from both studies are analogous, in the absence of chronic pulmonary emphysema. The diagnosis of chronic pulmonary emphysema is simple with the SEM even when dealing with autoptic material obtained 24 to 48 h after death, but the diagnosis of drowning becomes difficult in lungs with chronic emphysema.     

Sequencing of intersecting lines by combined lifting process and scanning electron microscopy

The chronological order in which two intersecting writing or typed strokes were made can be determined for several combinations of writing media by scanning electron microscope (SEM) examination, a lifting and transfer technique using Kromekote paper, or a combination of the transfer technique followed by SEM examination of the remaining material in the intersection. When non-destructive examination cannot provide unambiguous determination of sequence, judicious choice by the document examiner of which technique to use for a given combination of writing media and paper type can be made using known characteristics of the materials involved. The range of line-crossings which can be reliably sequenced is greater using a combined transfer and SEM technique than when the examination is limited to either technique alone.     

家兔烧死后气管、肺及心肌的病理形态学观察

目的探讨烧死的病理形态学依据。方法建立家兔烧死动物模型,用光镜、透射及扫描电镜观察10只生前烧死家兔气管、肺及心肌的病变;并与死后焚尸及非烧死的正常组(各5只)对照。结果透射电镜下,气管粘膜上皮完全脱落,成堆红细胞和纤维蛋白成分粘附在平滑肌表面。肺Ⅰ型上皮细胞结构基本完整连续,线粒体嵴有断裂、缺失;Ⅱ型肺泡上皮细胞微绒毛消失,多数细胞线粒体、板层小体、高尔基体未见异常,少数Ⅱ型肺泡上皮细胞质膜破损、染色质浓集、胞质内容丢失。心肌严重变性坏死,细胞膜破坏,线粒体极度肿胀,肌丝溶解并出现收缩带坏死。扫描电镜下,气管粘膜上皮有完整纤毛,但上皮大片脱落,少数区域纤毛上皮稀疏排列,有脱落柱状上皮附着在纤毛上;肺间皮细胞结构基本完整,微绒毛数量不一致;心内膜的内皮细胞大部脱落,暴露内皮下结缔组织,心肌纤维呈扭曲排列。死后焚尸及正常组对照组未见上述变化。结论烧死兔的光镜和电镜下气管、肺及心肌的病理形态学变化,能为生前烧死与死后焚尸的鉴别提供依据。     

Development of Latent Fingermarks on Various Surfaces Using ZnO‐SiO2 Nanopowder

Fingermarks are one of the most useful forms of evidence in identification and can provide generalized proof of identity in crime investigation. They are developed using various conventional powders. The novel nanopowder ZnO‐SiO₂ was synthesized via the conventional heating method and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy‐dispersive X‐ray (EDX) analysis, transmission electron microscope (TEM), and X‐ray diffraction (XRD). The mean particle size of ZnO‐SiO₂ nanopowder calculated through TEM was 32.9 nm. The development of fingermarks was carried out by powder dusting and small particle reagent (SPR) methods. Powder dusting method was used for the development of latent fingermarks on various dry, nonporous, and semi‐porous surfaces. The SPR method was also applied to wet nonporous surface. The developed latent fingermarks using ZnO‐SiO₂ nanopowder were found to have excellent quality with very clear third‐level ridges detail and had better visibility than commercially available white powder.     

Fatal postpartum coronary artery dissection. A light- and electron-microscope study

A case report of fatal spontaneous dissection of the distal left circumflex coronary artery in a 37-year-old postpartum female is presented. Samples of arterial wall from this patient and from six other postpartum females who died of unrelated causes were examined by light (LM), scanning electron (SEM), and transmission electron (TEM) microscopy. Morphological changes to explain the recognized predisposition of this cohort to coronary artery dissection were sought. The origin of the dissection was demonstrated by serial LM sections to be in midmedia with no intimal extension. The predominant plane of dissection was the junction of media and adventitia. Sarcolemmal blebbing and accumulation of amorphous intercellular material were demonstrated at the dissection site by SEM but were not seen elsewhere in the affected heart or in any of the six control hearts. These changes could not be distinguished by TEM from prolonged ischemic injury. There was no accumulation of eosinophilic leukocytes in the vessel wall or adventitia, and adventitial mast cells were not consistently more frequent than in the controls. No increase of stainable intramural mucopolysaccharides was seen in the fatal case. The results indicated no generalized arterial change in postpartum coronary arteries to account for the increased frequency of dissection. A focal degenerative process remains the most likely possibility.     

水、油污中无电流斑电击死大鼠皮肤和心肌的病变

目的探讨水中、油污中无电流斑电击死法医学鉴定的病理形态学依据。方法 SD大鼠28只,分为水中、油污中无电流斑电击死各1组,典型电流斑组、正常对照组、死后电击组、死后水中、油污中电击各1组共7组。采用肉眼、光镜及投射电镜观察水中、油污中无电流斑电击死大鼠皮肤和心肌组织病理学改变,并与其它各组进行比较。结果采用肉眼观察,生前水中、油污中无电流斑电击死大鼠皮肤未见明显电流斑。普通光镜观察,可见电击中心部位表皮变性坏死、脱落,表皮细胞变薄、致密,表皮细胞或/和毛囊、汗腺、皮脂腺发生极性化改变。电镜观察,透明层和角质层分离脱落,基底细胞肿胀、细胞器减少、核固缩,汗腺导管上皮肿胀,棘细胞中粗面内质网扩张融合成泡状,线粒体肿胀空泡化;但光镜与电镜的变化与生前电击死比较不明显、典型。而死后电击组皮肤则无明显病理学改变。实验各组大鼠心肌的改变与皮肤改变类同。结论采用光镜和投透射电镜观察在潮湿环境中电击死的组织病理学改变,可为无电流斑电击死提供依据。     

无电流斑电击伤的研究进展

无电流斑电击伤的鉴定是法医学中的难点之一,由于缺少明显的体表痕迹,此类案件的鉴定难度较大。国内外学者采用光镜、电镜、原子吸收光谱等仪器,利用组织化学等方法,对无电流斑电击伤进行了大量的研究,笔者在此将相关研究成果进行综述,希望能够为此类案件的鉴定提供一定的依据。     

Scanning electron microscopy determination of string mozzarella cheese in gastric contents

As part of a suspected homicide investigation, a sampling of the gastric contents from the victim was forwarded to the U.S. Food and Drug Administration's Forensic Chemistry Center (FCC) for analysis of specific, selected components. The victim was known to have consumed string mozzarella cheese, as a snack, less than 24 h before his disappearance and the subsequent discovery of the body. The investigation sought to confirm or dismiss speculation the victim may have been fed a meal or eaten additional food prior to his death. Analysis of the stomach contents involved examination by stereoscopic light microscopy (SLM) and isolation, processing, and analysis of suspect materials by scanning electron microscopy (SEM). Several wax-like, off-white to cream-colored objects were noted by SLM examination and removed from the gastric contents. Through a series of fixation, sectioning, drying, and coating steps, these objects were prepared for analysis by SEM. Comparison of the suspect material with laboratory control string mozzarella cheese showed excellent correlation between the analyzed samples, confirming the suspect material from the stomach contents as string mozzarella cheese.     

扫描电镜-能谱仪在毒物检验中的应用

目的建立扫描电镜-能谱仪检验氰化钠的方法。方法应用扫描电镜-能谱仪及化学反应法对案件的茶水和死者胃内容中的氰化钠成分进行检验。结果检验出了氰化钠成分。结论与传统分析方法相比,该方法具有快速、简便、准确以及不破坏试样的特点。     

Scanning electron microscopic analysis of skin resolution as an aid in identifying trauma in forensic investigations

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.     

Forensic analysis of soil and sediment traces by scanning electron microscopy and energy-dispersive X-ray analysis: an experimental investigation

This paper reports the results of a series of experiments carried out to determine the precision of soil trace comparisons based on elemental peak height ratios determined by energy-dispersive X-ray analysis (EDXRA) in a variable pressure scanning electron microscope (VP-SEM). Experiments were conducted on 'bulk' soil aggregates, ground powders prepared from the <150 microm soil fractions and on smears of both the bulk soil and <150 microm material placed on cotton cloth. X-ray count data were obtained using area scans and spot analyses at different magnifications. The effects on elemental peak height ratios of varying the SEM chamber pressure, beam spot size, emission current and accelerating voltage were also examined. The peak height ratios for oxygen, silicon, aluminium, potassium, calcium and iron were found to show little variation as a function of chamber pressure, spot size and emission current over the ranges examined, but a strong dependency on accelerating voltage was observed. Within-sample variation in results, expressed by the percentage coefficient of variation, was found to be lowest for area scan analyses of the ground <150 microm fractions and greatest for the spot analyses of the bulk soil aggregates and the <150 microm fractions. We conclude that comparison of elemental peak height ratios determined by EDXRA can be a useful tool for rapid screening of soil samples, especially when combined with investigation of other attributes of the soil traces such as colour, fabric and the composition, shapes and surface textures of individual particles or aggregates within the soil traces. If sufficient material is available and can be readily separated without contamination or loss, higher resolution and more precise elemental data should be obtained by methods such as inductively coupled plasma atomic-emission spectrometry (ICP-AES) or mass-spectrometry (ICP-MS).     

The Survival of Gunshot Residues in Cremated Bone: An Inductively Coupled Plasma Optical Emission Spectrometry Study

Gunshot residue (GSR) has been sought and demonstrated on many types of material and with many techniques. Inductively coupled plasma optical emission spectrometry (ICP‐OES) could be a useful method on difficult substrates, but a systematic study on burnt material has never been performed. Hence, this study aims at evaluating the usefulness and reliability of this method on burnt samples. Sixteen adult bovine ribs (eight with soft tissues, eight totally skeletonized) were shot using two kinds of projectile (both 9 mm full metal‐jacketed or unjacketed). Then, every sample was led to complete calcination in an electric oven. The area of the gunshot entrance wound was swabbed and analyzed by ICP‐OES; the results were also correlated with a previously published parallel study by scanning electron microscopy (SEM) equipped with an SEM–energy dispersive X‐ray analyzer. ICP‐OES proved to be very sensitive and reliable even on degraded material and can be an appropriate nondestructive method for detecting residues on difficult and delicate substrates such as burnt bone.     

Scanning electron microscopy as an auxiliary method in the study of exhumed bones

Scanning electron microscopy (SEM) has been used in forensic science in many ways. The reports of cases in which SEM has been used as an auxiliary method in the investigation of exhumed bones are rare. In this article, we report an exhumation that was made to determine if a seized weapon could have been used in a homicide. We used SEM to analyze a fracture in the interior of the skull of the victim. The findings described in this article showed us that it is possible to develop new researches in this field.     

Scanning electron microscopy analysis of experimental bone hacking trauma

The authors report on their macro- and microscopy study of bone lesions made by a sharp force instrument (a single blade knife), and a sharp-blunt instrument classified as a chopping weapon (a hatchet). The aim of this work was to attempt to identify the instrument by analyzing the general class characteristics of the cuts. Each weapon was used on human bones. The results indicate that macroscopic analysis is more problematic. The microscopic analysis assessed that characteristics examined were effective in distinguishing sharp from sharp-blunt injury to the bone. The microscope facilitates analysis unachievable with macroscopic methods, some three-dimensional characteristics not visible to the naked eye being clearly defined with its use. Emphasis has been placed on the value of SEM as an anthropologist's tool in bone lesion injuries.     

Use of scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDXA) in identification of foreign material on bullets

The authors report two cases in which examination of foreign material embedded in or adherent to bullets provided critical information in the reconstruction of a crime scene. Analysis of small particles by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA) can be accomplished without destruction or injury of the particles. In one case, the detection and identification of mineral fragments embedded near the nose of a bullet provided conclusive evidence that the bullet had ricocheted from a fireplace before striking the victim. In the second case, analysis of particles from two bullets identified them as them as bone fragments, thus proving which shots fired from a police officer's gun had killed a suspected burglar. SEM-EDXA has not been widely used to identify such material on bullets, but should be considered a potentially powerful tool in forensic science.     

环境扫描电镜在法庭科学中的应用与展望

环境扫描电镜（ESEM）在法庭科学的研究和实践工作中,有着重要的作用,它不仅具有普通扫描电镜的各类功能,还可以调整样品室内的气压和湿度,并且可在环境条件下对二次电子成像,因此,ESEM能够直接观察非导电导热样品表面的超微结构。这些特点使得ESEM在法庭科学中有着广阔的应用前景。     

Limitations of ZAF correction factors in the determination of calcium/phosphorus ratios: important forensic science considerations relevant to the analysis of bone fragments using scanning electron microscopy and energy-dispersive x-ray microanalysis

A series of calcium phosphate standards having calcium/phosphorus (Ca/P) molar ratios of 0.50, 1.00, 1.50, and 1.67, respectively, was prepared for bulk specimen analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDXA). The standards were mounted on carbon planchettes as either pure crystals or crystals embedded in epoxy resin. Ten different samples of each embedded and non-embedded standard were analyzed in a JEOL 100 CX electron microscope interfaced with a Kevex 8000 EDXA system using a lithium-drifted silicon detector and a multichannel analyzer. The Ca/P ratios were determined by calculating both net peak intensities without matrix corrections and atomic kappa-ratios using the MAGIC V computer program with ZAF correction factors for quantitative analysis. There was such extensive absorption of phosphorus X-rays in standards embedded in an epoxy matrix that the observed Ca/P ratios were statistically compatible with four different standards ranging in theoretical Ca/P ratios from 1.0 to 1.67. Although the non-embedded crystals showed a greater separation in the Ca/P ratios, both methods of preparation produced serious flaws in analysis. Direct application of the discovery of this caveat to the identification of suspected bone fragments for forensic science purposes is discussed.     

Morphological and chemical analysis of magic mushrooms in Japan

Morphological and toxicological analyses were performed on hallucinogenic mushrooms that are currently circulated in Japan. Scanning electron microscope (SEM) indicated a three-dimensional microstructures in the mushrooms. The complementary use of SEM with an optical microscope was effective for observing characteristic tissues, such as basidiomycetes, spores, cystidia and basidia. Hallucinogenic alkaloids were extracted with methanol and determined by high performance liquid chromatography (HPLC) with a UV detector set at 220 nm. The psilocin/psilocybin contents in Psilocybe cubensis were in the range of 0.14-0.42%/0.37-1.30% in the whole mushroom (0.17-0.78%/0.44-1.35% in the cap and 0.09-0.30%/0.05-1.27% in the stem), respectively. The hallucinogenic alkaloids in Copelandia were 0.43-0.76%/0.08-0.22% in the whole mushroom (0.64-0.74%/0.02-0.22% in the cap and 0.31-0.78%/0.01-0.39% in the stem). It thus appears that P. cubensis is psilocybin-rich, whereas Copelandia is psilocin-rich.