An improved method for detection of diatoms (author's transl)]

An improved method for detection of diatoms in case of drowning is reported. The sample is digested with nitric acid. In order to avoid destruction of diatoms as well as losses by centrifugation etc. the time for wet digestion was reduced and the digest solution is filtered through a membrane filter. Fatty material is removed by alternate washing the filter with 2-Propanol and Petroleum ether. Following the wet digestion of the filter, aliqutos of this digest solution are filtered and the filter is examined microscopically. As the recommended procedure is less time consuming and yields almost complete recovery of diatoms the method has great probative value in case of death by drowning.     

Photoluminescence of blood by acidic hydrogen peroxide—A preliminary test

In this study, the authors found that treating blood with 1 M HCl and 2% (w/v) 5-sulfosalicylic acid (SSA) in 1% (v/v) hydrogen peroxide mixture can produce photoluminescence of blood. SSA was added as a blood fixer. The photoluminescence was induced by irradiation of a forensic light source at 505 nm, which was detected using a 550 nm barrier filter. In this experiment, various level of acid and hydrogen peroxide were tested to find the optimal formulation of reagents, spot tests were conducted with diluted blood to test the sensitivity of this reagent, and impressions in blood left on porous/nonporous surfaces were enhanced. The sensitivity of this solution was slightly lower than Bluestar and was similar to leucocrystal violet or leucomalachite green on both porous/non-porous surfaces. The photoluminescence of blood treated with this reagent has been observed over 2 months. Using this reagent, it was possible to observe fingermarks or footwear impressions in blood on a black porous/non-porous surface. Through this, it was found that using this reagent could enhance bloodstains regardless of the porosity or color of the surface.     

Simultaneous determination of creatinine and uric acid in urine by liquid chromatography-tandem mass spectrometry with polarity switching electrospray ionization

A simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated to simultaneously determine creatinine (Cr) and uric acid (UA) levels as a confirmatory method for adulteration or dilution of urine. Centrifuged urine samples (10μL) were diluted with 390μL of distilled water. 30μL of internal standard solution (Cr-d(3), 5μg/mL) and 10μL of acetonitrile were added to 20μL aliquots of diluted urine samples and filtered. The samples (1μL) were introduced into LC-MS/MS with no further pretreatment. Cr and UA were separated on a multi-mode ODS column (Scherzo SM-C18, 75mm×2.0mm I.D., 3μm) and quantified by LC-MS/MS with polarity-switching electrospray ionization. Cr requires the positive-ion mode, whereas the negative-ion mode is required for the analysis of UA. The linear ranges were 1.0-300mg/dL for Cr and 0.5-300mg/dL for UA, with good determination coefficients (R(2)≥0.9988). The intra-day and inter-day precision of the analytes was within 13.0% and 14.4%, respectively. The intra-day and inter-day accuracy was -8.8 to 3.7% and -0.3 to 6.6%, respectively. The lower limits of detection (LLODs) were 0.3mg/dL for Cr and 0.07mg/dL for UA. The applicability of the developed method was examined by analyzing urine samples from suspected drug abusers (n=46).     

液相色谱-质谱联用测定血中氟乙酸类鼠药

目的建立血中氟乙酸类鼠药液相色谱-电喷雾离子阱质谱分析方法。方法血样经甲醇沉淀蛋白后离心,上清液用氮气吹干,流动相定容过滤膜,滤液直接进行液相色谱-电喷雾离子阱质谱联用分析。结果血中氟乙酸根在0.050μg/mL-2.0μg/mL之间具有良好的线性关系,最低检出限为0.020μg/mL。结论本文建立的方法快速、灵敏、操作简便,适用于刑事案件中该类氟乙酸类鼠药的快速检验,具有一定的实用价值。     

Forensic implications of respiratory derived blood spatter distributions

The nature of blood aerosols produced in physiological studies of an upright subject expiring small volumes through straws, spitting and mouthing sounds, and a semi-prone subject spitting through a bloody mouth or snorting through a single nasal orifice and by a simplified physical model of the respiratory system were investigated. Each manoeuvre produced many hundreds of droplets of a range of size, the vast majority being less than 1mm diameter. Droplets under 1mm dia. travelled over 1m - much further than could be expected if their flight was ballistic, like that of impact spatter. Respired blood aerosol properties are explained in terms of established mechanics of airflow shear induced aerosol production and the fluid mechanics of exhaled air movement.     

An evaluation of the underlying mechanisms of bloodstain pattern analysis error

An experiment was designed to explore the underlying mechanisms of blood disintegration and its subsequent effect on area of origin (AO) calculations. Blood spatter patterns were created through the controlled application of pressurized air (20-80 kPa) for 0.1 msec onto suspended blood droplets (2.7-3.2 mm diameter). The resulting disintegration process was captured using high-speed photography. Straight-line triangulation resulted in a 50% height overestimation, whereas using the lowest calculated height for each spatter pattern reduced this error to 8%. Incorporation of projectile motion resulted in a 28% height underestimation. The AO xy-coordinate was found to be very accurate with a maximum offset of only 4 mm, while AO size calculations were found to be two- to fivefold greater than expected. Subsequently, reverse triangulation analysis revealed the rotational offset for 26% of stains could not be attributed to measurement error, suggesting that some portion of error is inherent in the disintegration process.     

High-performance liquid chromatography with column switching for the determination of cocaine and benzoylecgonine concentrations in vitreous humor

A sample concentration technique was adapted for the determination of cocaine and benzoylecgonine (BE) concentrations in vitreous humor. Vitreous humor (0.5 mL) was diluted 1:1 with water and applied through a filter onto a 3-cm preconcentration column. Following a simple wash step, the analytes were flushed directly onto a reversed-phase analytical high-performance liquid chromatography (HPLC) system. Absolute recoveries were high (above 90%) and the chromatograms were free from interference. Analysis for the drug and its breakdown product was performed using ultraviolet (UV) visible photodiode array detection, which allowed confirmation of peak identity. Recognizable UV spectra could be measured with as little as 20 ng on column. Comparison of the drug levels in 27 blood and vitreous humor samples showed that, while there was only a low correlation between the blood and vitreous concentrations (R = 0.70), vitreous cocaine and BE determinations were good indicators of antemortem cocaine use. In almost all cases, the vitreous BE concentrations were higher than the cocaine concentrations. The technique was easy to perform and the vitreous samples were especially compatible with this low-labor analytical procedure.     

衍生化-液相色谱-质谱联用测定血中氟乙酸类杀鼠剂

目的建立血中氟乙酸类杀鼠剂衍生化-液相色谱-电喷雾离子阱质谱分析方法。方法血样经乙腈沉淀蛋白后离心,上清液中加入衍生化试剂α-溴苯乙酮和催化剂四丁基溴化铵,在60℃水浴中加热90min,衍生化产物直接进行液相色谱-电喷雾离子阱质谱联用分析。结果血中氟乙酸根浓度在0.15μg/mL～15.40μg/mL之间具有良好的线性关系,最低检出限为0.020μg/mL。结论本文建立的方法操作简便、灵敏、快速,适用于刑事案件中氟乙酸类杀鼠剂的快速检验。     

LC-MS/MS法快速测定全血中25种精神药物的研究

目的建立人全血中25种精神药物快速测定的LC-MS/MS方法,并应用于分析杭州地区药物影响下驾驶(driving under the inference of drugs,DUID)情况。方法以乙腈沉淀蛋白,离心后取上清液,氮气流下吹干,残渣以初始流动相复溶,离心后取上清分析;采用C18色谱柱(50mm×3.0mm,2.6μm)分离,流动相:0.1%甲酸水(A相),乙腈:甲醇=1:1(B相),梯度洗脱;质谱检测,采用串联质谱电喷雾离子源,正电离扫描,多反应监测(MRM)。结果 25种精神药物在0.05~20ng/m L范围内线性良好,R=0.994 4~0.999 6;定量下限为0.05ng/m L;提取回收率为83.0%~99.7%;方法回收率为80.2%~97.4%;日内精密度(RSD)为1.6%~14%;日间精密度(RSD)为3.1%~14%。以该法测定杭州市公安司法鉴定中心留存的全血样品3140例,25种精神药物至少一种的检出率为3.7%。结论本方法灵敏、快捷、准确,适用于全血中25种精神药物快速检测。     

Vacuum collection of gunpowder residues from clothing worn by shooting suspects, and their analysis by GC/TEA, IMS, and GC/MS

Experiments were conducted to collect gunpowder (propellant) residues from shooters' clothing by vacuum and to analyze them by gas chromatography/thermal energy analyzer (GC/TEA), ion mobility spectrometry (IMS), and gas chromatography/mass spectrometry (GC/MS). The residues were collected on fiberglass and Teflon filters using the portable vacuum sampler, all supplied with the IMS instrument. Several solvents were examined for the extraction of the propellant components from the filters. The extracts were centrifuged and/or filtered, concentrated by evaporation, and analyzed without any additional clean-up procedure. Based on the results of the study, an operational method for analysis of gunpowder residues was introduced into casework without changing the present operational technique for gunshot (primer) residue (GSR) analysis on clothing implemented by the Israel Police. In the modified method, the clothing is first sampled by double-side adhesive-coated aluminum stubs (the tape-lift method) for GSR analysis (the existing method), followed by vacuum collection for propellant residue examination. The issue of interpretation of the analytical results is discussed.     

HPLC-UVD/FLD法测定血中氟乙酸类杀鼠剂

目的采用水相催化衍生化-液相色谱-紫外/荧光检测分析法,检测血中氟乙酸类杀鼠剂。方法血样经乙腈沉淀蛋白后,加入衍生化试剂4-溴甲基-7-甲氧基香豆素、催化剂四丁基溴化铵,在80℃水浴中衍生化反应120min,衍生产采用液相色谱-紫外/荧光检测分析。结果紫外检测法:氟乙酸根浓度在0.38～38.50μg/mL之间线性关系良好,最低检出限为0.10μg/mL;荧光检测法:氟乙酸根浓度在0.15～15.40μg/mL之间线性关系良好,最低检出限为0.050μg/mL。结论水相催化衍生化-液相色谱-紫外/荧光检测分析方法具有较好的灵敏度、准确性和精密度,可用于实际案例检测。     

水浸和洗涤血样本的DNA检验

目的对经水作用的血样本DNA分型检验结果进行分析探讨。方法全血样本分为两组,水稀释组用水将全血样本稀释5、10、20、25、30倍后制作血斑;洗涤组分为纯水手洗、肥皂弱洗、肥皂强洗、84消毒液浸洗和洗衣粉机洗等5种洗涤方式。所有样本用IQ试剂盒提取DNA,Identifiler PlusTM试剂盒扩增,并进行分型检测。结果血液稀释组中心部位检材,均无等位基因丢失,除30倍稀释样本外,峰高均衡性均大于70%;外周部位检材出现2～10个等位基因丢失,峰高均衡性均小于50%。洗涤组中除84消毒液洗涤样本未检出DNA谱带外,其余均无等位基因丢失,而峰高及均衡性以手洗和肥皂弱洗样本更好。结论经水稀释或洗涤剂清洗的血样本,即使联苯胺预实验结果为阴性,选取合适的检验部位,仍可获得DNA分型。     

Reactions of latent prints exposed to blood

We explored whether an undeveloped latent print (fingermark) exposed to blood and later developed by enhancement with blood reagents such as amido black (AB) or leucocrystal violet (LCV) could appear as a genuine blood mark. We examined three different experimental conditions. In Experiment I, fingermark residue only was tested, as a control to confirm that fingermark residue alone does not react with the blood reagents AB and LCV. Experiment II investigated whether latent fingermarks exposed to blood dilutions could be treated with AB or LCV and subsequently appear as a genuine blood mark enhanced with AB or LCV. Experiment III tested whether latent fingermarks exposed to whole blood could be processed with AB or LCV and subsequently appear as a genuine blood mark enhanced with AB or LCV.The present study found that indeed, fingermark residue alone does not react with the blood reagents AB and LCV. In Experiment II, an interaction occurred between the fingermark residue and the diluted blood that caused the ridges to appear a red color. In the present study, this interaction is called a faux blood mark. While the faux blood mark phenomenon occurred most often following exposure to diluted blood, it did not occur consistently, and a predictable pattern could not be established. However, the reaction occurred more frequently following extended fingermark residue drying times. Faux blood marks are distinguishable from genuine blood marks prior to enhancement with blood reagents. Following treatment with blood reagents, it became increasingly difficult to determine whether the enhanced mark was a genuine blood print or a latent fingermark exposed to diluted blood. Latent fingermarks exposed to whole blood often resulted in a void prior to enhancement, but following treatment with blood reagents, were difficult to distinguish from a genuine blood mark enhanced with blood reagents.     

血尿肝中巴比妥类药物硅藻土提取紫外差示导数光谱测定

目的建立一种操作简单、快速、去除杂质能力强、提取率高的硅藻土提取血、尿、肝中巴比妥类药物的方法。方法尿液不经稀释、血液经稀释过硅藻土柱,乙醚洗脱;肝匀浆用6%高氯酸沉淀蛋白,上清液过硅藻土柱,二氯甲烷洗脱药物。洗脱液挥干用0.45mol/L氢氧化钠溶液溶解,将溶液等分为两份,分别用等量的0.45mol/L氢氧化钠溶液和0.6mol/L硼酸-氯化钾溶液稀释,得到pH10和pH14水溶液,以pH10溶液为参比,测定pH14溶液的紫外二阶导数光谱进行药物检测。结果该法提取率血98.6%~100.3%,尿99.7%~103.2%,肝78.4%~102%,检出限均低于1.0μg/g(m l),变异系数小于2.9%,线性范围0.5~5.0μg/m l。结论硅藻土提取血、尿、肝中巴比妥类药物、紫外差示导数光谱法进行测定,适合作为法医毒物常规检验方法。     

Deducing drop size and impact velocity from circular bloodstains

An experimental study was done to determine the diameter and velocity of blood drops falling on a surface by measuring the size of bloodstains they produced and counting the number of radial spines projecting from them. Bloodstains were formed by releasing drops of pig blood with a range of diameters (3.0-4.3 mm) and impact velocities (2.4-4.9 m/s), onto four different flat surfaces (glass, steel, plastic, paper) with varying roughness (0.03-2.9 microm). High-speed photography was used to record drop impact dynamics. Bloodstain diameters and the number of spines formed around the rim of stains increased with impact velocity and drop diameter. Increasing surface roughness reduced stain diameter and promoted merging of spines, diminishing their number. Equations are presented that explicitly relate drop diameter and impact velocity to measurements of stain diameter and number of spines.     

Analysis of DNA in minute volumes of blood from stains and crusts

As the first step, the locus D1S80 was amplified by the polymerase chain reaction technique from genomic DNA extracted from artificial bloodstains and crusts with different amount of blood (32 microl, 16 microl, 8 microl, 4 microl, 2 microl, and 1 microl). In all samples of bloodstains and crusts, identification by DNA analysis was possible. As the second step, the locus HLA-DQA1 was amplified from genomic DNA extracted from diluted blood samples (640, 320, 160, 80, 40, 20, 10, and 5 leukocytes). DNA amplification was possible in diluted blood samples with at least 10 leukocytes. Considering the conditions in which the present study was carried out, it was possible to conclude that 1 microl of bloodstains or crusts was enough for identification. It was also concluded that five leukocytes are not enough material to render consistent DNA identification.     

The development of a filter model for prioritising suspects in burglary offences

Abstract

This paper discusses the development of a filter model for prioritizing possible links in dwelling burglary. The filters utilize the central aspects of crime scene information that is available and accessible to investigators in burglary, namely geo-spatial, temporal, behavioural, and dwelling information. The proposed filters were analysed using a sample of 215 dwelling burglaries committed by 43 serial burglars (i.e. 5 offences each) in order to determine the sequence in which the filters should be considered in prioritizing possible linked offences. The results indicated that the following order (i.e. better performance to worse performance) was most effective at linking offences, utilizing: (1) geo-spatial information, (2) temporal aspects, (3) behavioural information and, lastly, (4) dwelling characteristics. Specifically, the results indicated that offences in close proximity to one another should be given priority. Further, any offence occurring within a 28-day span before or after the index offence should be given priority. The paper argues that behavioural and dwelling characteristics are less effective for linking than geo-spatial and temporal information because the former two aspects are influenced significantly by situational and contextual cues on offender decision-making.     

Subvalvular aortic stenosis as a cause of sudden death: two case reports

Sudden death is defined as a death that occurs suddenly, develops during an unpredictable course, and is due to natural or unnatural causes. Although there is no universally standardized definition on how "sudden" a sudden death is, WHO defines sudden death as a death that occurs within 24 hours after the onset of symptoms. The aim of this study is to present 2 rarely reported autopsy cases and to emphasize the importance of systemic autopsy at sudden death. On macroscopic examination, crescent-shaped, thick, fibrous membranes, located 5 mm and 3 mm away from the aortic valves, were detected. Fibrous membranes extended from the ventricular septum to the left ventricular outflow tract, thus apparently narrowing this region. Left ventricular wall and septum were slightly thickened, and there were scattered grayish-white areas of a small diameter. These became more intense in the septum and myocardium of the left ventricle on the anterior plane of the myocardial sections. In both cases, the aortic valves of were thickened and also markedly narrowed on one of them. In this case, the fibrous membrane adhered to the aortic valve and extended to the anterior leaflet of the mitral valve at one side. Both aortic valves comprised 3 leaflets. Other valves and coronary arteries showed no macroscopic pathologic findings. Microscopic examination of both cases demonstrated that the fibrous membrane comprising abundant collagen fibers was situated on the ventricular septum. Hypertrophy, moderate to severe interstitial fibrosis, and focal areas of scarring were observed in the specimens taken from the septal and ventricular myocardium. No abnormality was found on the conduction system examinations. Toxicologic analysis results in blood were negative. Based on the findings, membranous-type (discrete type) subvalvular aortic stenosis, diagnosed during the autopsy, was considered as the cause of sudden death in both cases.     

Identification of fetal blood stains by radioimmunoassay of alpha 1-fetoprotein.

Radioimmunoassay of alpha 1-fetoprotein(AFP) for medico-legal identification of fetal blood stains using a commercial kit is described. The AFP content in fetal blood stains on filter paper ranged from 21--320 ng/9 mm2. The protein was detected in stains of adult blood and retroplacental blood in only negligible amounts. Aging of the blood stains did not influence the values up to 1 month. The method is simple and sensitive enough for application to medico-legal-practice.     

Sex determination with the head of the radius

Analysis of a sample of 1108 radii corresponding to 567 black and white North Americans in the Terry Collection at the Smithsonian Institution demonstrates that the diameter of the radial head is an accurate sex discriminator for human remains. A simple "radial-head method" of sex determination consists of measuring the maximum and minimum diameters of the head and comparing such measurements with the test cutoff points. The subject is female when the maximum radial head diameter (either left or right) is less than or equal to 21 mm, and male when the maximum diameter (either left or right) is greater than or equal to 24 mm. The same decisions apply to the minimum diameters of 20 mm or less and 23 mm or more, respectively. When the maximum diameter is 23 mm or the minimum is 22 mm, the subject is more likely male; when the maximum diameter is 22 mm or the minimum is 21 mm, the subject is more likely female. The sample frequency of any one of these latter diameters is never more than 16%. Cross-validation of the method with a sample of 50 pairs of radii of the Terry Collection, different from the original specimens, resulted in 92% sexing accuracy when using the left radius singly, 94% accuracy when using the right radius singly, and 96% accuracy when using both radii jointly.