Vegetation dynamics as a tool for detecting clandestine graves

The burial of a body can affect plant communities through mechanical disturbance and nutrient balance alteration. We performed an experimental trial using five swine carcasses buried in an open site in Italy. Vegetation dynamics was monitored recording monthly every plant individual on a regular sampling grid during 1 year on the graves, on an empty control grave, and on an undisturbed plot. Plant species composition and cover were significantly different between the disturbed and the undisturbed plots. Disturbed plots showed the increase in ruderal species and the reduction in stress-tolerant ones. Graves and the control grave could not be distinguished from each other. Disturbance was the main factor affecting plant cover, while the presence of a buried body did not affect vegetation dynamics. However, disturbance could be easily detected; the functional approach seems promising for the identification of dynamic patterns to be used in different biogeographic and ecological contexts.     

Comparative Analysis of the Chemical Profiles of 3,4-Methylenedioxymethamphetamine Based on Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry (GC × GC-TOFMS)*

Abstract: The chemical profiling of illicit drugs is an important analytical tool to support the work of investigating and law enforcement authorities. In our work, comprehensive two‐dimensional gas chromatography–time‐of‐flight mass spectrometry (GC × GC‐TOFMS) combined with nontargeted, pixel‐based data analysis was adapted for the chemical profiling of 3,4‐methylenedioxymethamphetamine (MDMA). The validity and benefit of this approach was evaluated by analyzing a well‐investigated set of MDMA samples. Samples were prepared according to a harmonized extraction protocol to ensure the comparability of the chemical signatures. The nontargeted approach comprises preprocessing followed by analysis of variances as a fast filter algorithm for selection of a variable subset followed by partial least squares discriminant analysis for reduction to promising marker compounds for discrimination of the samples according to their chemical profile. Forty‐seven potential marker compounds were determined, covering most of the target impurities known from the harmonized one‐dimensional profiling as well as other compounds not previously elucidated.     

Trace detection of meglumine and diatrizoate from Bacillus spore samples using liquid chromatography/mass spectrometry

Following the September 11, 2001 terrorist attacks, letters containing Bacillus anthracis were distributed through the United States postal system killing five people. A complex forensic investigation commenced to identify the perpetrator of these mailings. A novel liquid chromatography/mass spectrometry protocol for the qualitative detection of trace levels of meglumine and diatrizoate in dried spore preparations of B. anthracis was developed. Meglumine and diatrizoate are components of radiographic imaging products that have been used to purify bacterial spores. Two separate chromatographic assays using multiple mass spectrometric analyses were developed for the detection of meglumine and diatrizoate. The assays achieved limits of detection for meglumine and diatrizoate of 1.00 and 10.0 ng/mL, respectively. Bacillus cereus T strain spores were effectively used as a surrogate for B. anthracis spores during method development and validation. This protocol was successfully applied to limited evidentiary B. anthracis spore material, providing probative information to the investigators.     

Sudden and unexpected death from pituitary tumor apoplexy

Pituitary tumor apoplexy refers to a clinical syndrome precipitated by the expansion of a pituitary adenoma by hemorrhage or infarction. Individuals may present with myriad signs, including sudden onset of severe headache, visual changes, altered mental status, cranial nerve palsies, and hormonal dysfunction. This disorder constitutes a medical emergency and warrants an expedited evaluation, diagnosis, and treatment to prevent the potential sequelae of permanent visual loss, endocrine abnormalities, or death. We report a case of sudden death from undiagnosed pituitary tumor apoplexy. The decedent was evaluated by medical personnel on three occasions in the week prior to her death for severe headache, nausea, vomiting, and photophobia. Postmortem examination demonstrated a hemorrhagic infarction of a pituitary adenoma with necrosis and expansion out of the sella turcica. The recognition of and treatment for a patient with pituitary tumor apoplexy requires a rapid multidisciplinary effort. Failure of prompt diagnosis may be fatal and require a medico-legal death investigation for sudden and unexpected death.     

Nanoscale analysis of the interaction between cyanoacrylate and vacuum metal deposition in the development of latent fingermarks on low-density polyethylene

Vacuum metal deposition (VMD) has been previously demonstrated as an effective development technique for latent fingermarks and in some cases has been shown to enhance prints developed with cyanoacrylate (CA) (superglue) fuming. This work utilizes scanning electron microscopy (SEM) to investigate the interactions of the two development techniques when applied to latent fingermarks on low-density polyethylene. CA is shown to act principally on the eccrine deposits around sweat pores, where polymerization results in long polymer fibrils a few 100 nm in width. Subsequent VMD processing results in additional areas of development, for example, between pores. However, the primary mode of deposition of zinc is by interaction with the polymerized CA, the fibrils of which become decorated with zinc nanoparticles. Areas with limited CA deposition and no significant polymerization are also enhanced with the VMD process, resulting in increased print development.     

Reproducibility of facial soft tissue thicknesses for craniofacial reconstruction using cone-beam CT images

The purpose of this study was to evaluate the reproducibility of the soft tissue (ST) thicknesses at 31 landmarks using the cone-beam computed tomography (CBCT) images obtained from 20 adult subjects. Four observers carried out ST thickness measurements using Skull Measure software, and the inter- and intra-observer error rates were evaluated. Only five of 31 landmarks showed significant differences in recorded ST thickness between the observers. When excluding inexperienced observers, only one landmark showed a significant difference between the observers. Regarding the intra-observer reproducibility, the ST thickness measurements at three landmarks showed low correlation coefficients. The results of this study indicate that CBCT images can be used to measure ST thickness with high reproducibility. However, some landmarks need to be redefined to reliably measure ST thickness on CBCT images.     

Rapid in situ repeatable analysis of drugs in powder form using reflectance near-infrared spectroscopy and multivariate calibration

This study takes the first step toward in situ analysis of powder drugs which does not require any alteration of the samples. A fast, inexpensive analytical method based on reflectance near-infrared (NIR) spectrometry and multivariate calibration was applied. A diode-array fiber-optic portable spectrometer in the 900-1700 nm range was employed. Samples were laboratory-prepared ternary powders (diacetylmorphine, caffeine, and paracetamol). Partial least squares regression was applied. The choice of the standard samples for calibration and validation was performed through a D-optimal experimental design. The explained variance was higher than 90%, and the relative root mean square errors were <2%. The number of principal components (6) was very low when compared with the number of raw variables (356 absorbance values). Response plots showed slopes and intercepts were very close to optimal values. Correlation coefficients ranged between 0.909 and 0.989. The method here proposed proved to be competitive with Fourier transform NIR spectrometry.     

Comparison of two methods for isolating DNA from human skeletal remains for STR analysis

Abstract: The quality and efficiency of a standard organic DNA isolation method and a silica‐based method using the QIAGEN Blood Maxi Kit were compared to obtain human DNA and short tandem repeats (STRs) profiles from 39 exhumed bone samples for paternity testing. DNA samples were quantified by real‐time PCR, and STR profiles were obtained using the AmpFlSTR^® Identifiler^® PCR amplification kit. Overall, the silica‐based method recovered less DNA ranging from 0 to 147.7 ng/g (average 7.57 ng/g, median = 1.3 ng/g) than did the organic method ranging from 0 to 605 ng/g (average 44.27 ng/g, median = 5.8 ng/g). Complete profiles (16/16 loci tested) were obtained from 37/39 samples (95%) using the organic method and from 9/39 samples (23%) with the silica‐based method. Compared with a standard organic DNA isolation method, our results indicate that the published silica‐based method does not improve neither the quality nor the quantity of DNA for STR profiling.     

The changes of fourier transform infrared spectrum in rat brain

Estimation of the time since death (postmortem interval [PMI]) is one of the most difficult problems in forensic investigations, and many methods currently are utilized to estimate the PMI. The goal of this study was to investigate the changes of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra of rat brain from postmortem time 0-144 h. The intensity ratios of major absorbance bands were examined (I(1066)/I(1392), I(1168)/I(1392), I(1234)/I(1454), I(1301)/I(1392), I(1647)/I(2956), I(2921)/I(2850), and I(1647)/I(1539)). The spectra of rat brain displayed prominent changes with increasing PMI. The band at 2871 and 1737 per cm became weak with the time increasing and even disappeared at postmortem 96 and 72 h, respectively. A close linear correlation was shown between the relative absorption intensity and the PMI, and the I(1234) /I(1454) offered a stronger correlation (r = 0.973). Our results indicate that ATR-FTIR spectroscopy may be a useful technique for estimating the PMI.     

Sex determination from the talus of Koreans by discriminant function analysis

The aims of this study were to investigate the sex discriminating potential of the talus in Koreans and compare this with other analyses in different populations. Statistical analyses were performed using data from nine measurements acquired from 140 tali (70 men, 70 women). The talus of Koreans is dimorphic between sexes in all measurements (p < 0.01). Discriminant function equations were generated by univariate, multivariate, and stepwise methods with a range of accuracy from 67.1 to 87.1%. Stepwise equations of other populations did not discriminate the sex of the Korean sample as accurately as each equation's own accuracies. The variables with high accuracy in this study are useful for sex determination of Koreans on the basis of confirmation of population specificity.