"Click and Screen" Technology for the Detection of Explosives on Human Hands by a Portable MicroNIR-Chemometrics Platform.

Portable near-infrared spectroscopy (MicroNIR) coupled with chemometrics was investigated for the first time as a new tool for the on-site analysis of explosives on human hands. A novel, entirely on-site approach based on the use of a particular miniaturized NIR spectrometer was developed and validated in cooperation with the Scientific Investigation Department (Carabinieri RIS) of Rome. Spectra from 25 volunteers were acquired in the NIR region in reflectance mode, and a prediction model was optimized on the basis of chemometric tools. The results demonstrated the capability of the MicroNIR-Chemometrics approach to correctly identify explosives from hands and not be affected by the complexity and variability of the matrix. This study has shown that the MicroNIR-Chemometrics approach can be considered a useful, fast, nondestructive tool identifying the manipulation of explosives in real forensic cases.

An initial exploration of machine learning for establishing associations between genetic markers and THC levels in Cannabis sativa samples.

Cannabis sativa, a globally commercialized plant used for medicinal, food, fiber production, and recreation, necessitates effective identification to distinguish legal and illegal varieties in forensic contexts. This research utilizes multivariate statistical models and Machine Learning approaches to establish correlations between specific genotypes and tetrahydrocannabinol (Δ9-THC) content (%) in C. sativa samples. 132 cannabis leaves samples were obtained from legal growers in Piedmont, Italy, and illegal drug seizures in Turin. Samples were genetically profiled using a 13-loci STR multiplex and their Δ9-THC content was detected through quantitative GC-MS analysis. This study aims to assess the use of supervised classification modelling on genetic data to distinguish cannabis samples into legal and illegal categories, revealing distinct clusters characterized by unique allele profiles and THC content. t-distributed Stochastic Neighbor Embedding (t-SNE), Random Forest (RF) and Partial Least Squares Regression (PLS-R) were executed for the machine learning modelling. All the tested models resulted effective discriminating between legal samples and illegal. Although further validation is necessary, this study presents a novel forensic investigative approach, potentially aiding law enforcement in significant marijuana seizures or tracking illicit drug trafficking routes.

A quantitative differentiation method for plastic bags by infrared spectroscopy, thickness measurement and differential scanning calorimetry for tracing the source of illegal drugs.

Fifty shopping bags, commonly encountered in the packaging of drug doses, were characterized by thickness measurements, infrared spectroscopy and differential scanning calorimetry. By these very straightforward and inexpensive techniques, without sample preparation, nearly all the considered samples could be discriminated. Ninety-seven percent of the possible pairs of white, apparently similar dull polymer films were differentiated. The rather large degree of variability existing in grocery bags, even though they are mass produced, was shown, confirming that these items can be useful in tracing the source of illicit drug doses.

Cuts and tears on a paper towel: a case report on an unusual examination of damage.

The examination of damage to a paper towel, an item of evidence in a murder case, is described. Simulations performed with selected tools and the observation of the lacerations present on the towel permitted to infer that they were originated by cleaning of a pointed and sharp implement. Some marks, considered characteristic of scissors, were detected on the exhibit. This experimental outcome resulted critical in challenging the declarations of the suspect. A rather significant analogy between damage examination on paper towels and on textiles was established.

Employing glass refractive index measurement (GRIM) in fiber analysis: a simple method for evaluating the crystallinity of acrylics.

The refractive index (RI) of 40 colorless acrylic fiber samples was determined by the immersion oil and Mettler hot stage method, implemented in the glass refractive index measurement (GRIM) instrument by Foster and Freeman. Low standard deviations for nearly all the samples were obtained and differentiation of fibers even with the same trade name was possible just on the basis of RI. Wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) were employed to establish a linear correlation between RI and the degree of crystallinity. Insights on the structural order of this group of fibers is then obtainable by a quick and easy technique, adding value to casework comparisons.

A quantitative differentiation method for acrylic fibers by infrared spectroscopy.

Absorbance peak areas of nitrile (2240 cm(-1)), carbonyl (1730 cm(-1)) and CH (1370 cm(-1)) groups were obtained for 48 colorless acrylic fibers by infrared (IR) microspectroscopy. The carbonyl signal, related to the comonomers most commonly used in acrylic fibers, was ratioed against the nitrile and CH bands, pertaining to the backbone of the polymer chains. The ratios A1730/A2240 and A1730/A1370, a relative measure of the comonomer content in the fiber, were used to differentiate the samples. A decrease in the crystallinity of fibers has been noted with increasing comonomer content. Relative standard deviation (R.S.D.) of the ratios were 1 and 3% for repetitive analyses on the same location and along the length of the same single fiber, respectively. When different fibers of the same sample were examined, results were reproducible within 6%. This simple method can greatly enhance the evidential value of colorless acrylic fibers, being able to discriminate them and thus helping the Court to better assess their significance.

Bayesian framework for the evaluation of fiber evidence in a double murder--a case report.

Fiber evidence found on a suspect vehicle was the only useful trace to reconstruct the dynamics of the transportation of two corpses. Optical microscopy, UV-Vis microspectrophotometry and infrared analysis were employed to compare fibers recovered in the trunk of a car to those of the blankets composing the wrapping in which the victims had been hidden. A "pseudo-1:1" taping permitted to reconstruct the spatial distribution of the traces and to further strengthen the support to one of the hypotheses. The Likelihood Ratio (LR) was calculated, in order to quantify the support given by forensic evidence to the explanations proposed. A generalization of the Likelihood Ratio equation to cases analogous to this has been derived. Fibers were the only traces that helped in the corroboration of the crime scenario, being absent any DNA, fingerprints and ballistic evidence.

[Illicit market of controlled drugs in Italy: new drugs and trends]. / Il mercato illecito delle sostanze stupefacenti in Italia: nuove droghe e trend di sviluppo.

The data related to abuse and seizures of the main classes of controlled drugs in Europe and Italy are presented. The system of keeping up-to-date the tables of controlled drugs in Italy is briefly discussed. In the end, a list of the main new drugs in the clandestine market of synthetic drugs in Italy is presented, by taking into account the street names, doses and pharmacological effects. The paper ends with a brief description of the new trend of purchasing controlled drugs on internet sites.

[Drugs detection in street samples]. / Il rilevamento delle droghe nei campioni da strada.

The various steps of the analytical process are taken into account with reference to procedural problems linked to sampling operations, too. In particular, these aspects are treated: sampling procedures related to the various aspects of street samples, representative sampling of big amounts of controlled drugs, procedural problems in sampling of small amounts of drugs, the main methods of concealing. Up-to-date methods of extraction and chromatographic analysis are described. In the end, chemical profiling methods used to link different seizures of controlled drugs are briefly discussed.

A method based on thermogravimetry/differential scanning calorimetry for the forensic differentiation of latex gloves.

Latex gloves are quite frequently employed by felons, when committing crimes, if they want to avoid shedding fingerprints or biological traces. Less forensic aware crime committers, though, may discard the gloves at the crime scene or nearby. If found and properly analyzed, these items may therefore provide useful information to investigators. An analytical procedure of such items is proposed, using thermogravimetry and differential scanning calorimetry. By these very straightforward and inexpensive techniques, without sample preparation, nearly all the considered samples could be discriminated. 99.5% of the possible pairs of latex gloves, indistinguishable by visual examination, were differentiated. The rather large degree of variability existing in latex gloves, even though they are mass produced, was shown, confirming that these items can be useful in comparisons between items related to the crime scene and those seized in the suspect's premises.

The discrimination potential of ultraviolet-visible spectrophotometry, thin layer chromatography, and Fourier transform infrared spectroscopy for the forensic analysis of black and blue ballpoint inks.

The knowledge of the discriminating power of analytical techniques used for the differentiation of writing inks can be useful when interpreting results. Ultraviolet-visible (UV-VIS) spectrophotometry, thin layer chromatography (TLC), and diffuse reflectance Fourier transform infrared spectroscopy (FT-IR) were used to examine a population of 21 black and 12 blue ballpoint writing inks. Based on corroborative results of these methods, the discrimination power for UV-VIS, TLC, and FT-IR was determined to be 100% and 98% for the black and blue inks, respectively. Generally, TLC and UV-VIS can be used to differentiate the colorant components (i.e., dyes and some pigments) found in inks. As FT-IR can be utilized to identify some of the noncolorant components, it was determined to be an excellent complementary technique that can be implemented into an analytical scheme for ink analysis.

A quantitative differentiation method for plastic bags by wide angle X-ray diffraction for tracing the source of illegal drugs.

Thirty-three shopping bags, commonly encountered in the packaging of drug doses, were characterized by wide angle X-ray diffraction (WAXD). Using this single technique, without sample preparation, nearly all the considered samples could be differentiated, achieving a discriminating power of 0.992. The rather large degree of variability existing in grocery bags, even though they are mass produced, was shown, confirming that these items can be useful in tracing the source of illicit drug doses.