Fibre persistence on static textiles under outdoor conditions.

The persistence of fibres under outdoor conditions is seldom investigated. This research aimed to study simultaneously the influence of several factors (and their cross-interactions) on the persistence of fibres on static textile surfaces. In order to achieve this aim, a design of experiments was successfully implemented under laboratory conditions. Four factors were considered: time, inclination of the recipient textile, wind speed, and rainfall. The model obtained by this supervised method was compared with the results collected under actual outdoor conditions near a weather station. The resulting model appears to be reliable as long as the values of the factors are kept within the range used in the study. The results of the laboratory tests showed that wind speed and rainfall significantly influence the persistence of fibres while time and inclination of the recipient textile have been found to be nonsignificant. In general, the observed persistence was high: between 90.4 and 100%. This might be attributed to the recipient textile surface possessing abundant protruding fibres which "traps" the transferred fibres. Outdoor experiments usually suffer from a higher variability and result in a higher fibre loss. In outdoor conditions, wind and rainfall have shown an extensive influence on the fibre persistence. Finally, the trend of fibre persistence on static textiles in outdoor conditions is generally linear with time, but extreme meteorological condition will induce exponential losses.

Interpol review of fibres and textiles 2016-2019.

This review paper covers the forensic-relevant literature in fibres and textiles from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

Nylon flocked swab severely reduces Hexagon Obti sensibility.

Hexagon Obti immunological blood test and flocked swab are widely used in forensic laboratories. Nevertheless, up to now, no compatibility tests have been published between sampling with the ethylene oxide treated flocked swab and the Hexagon Obti blood detection strip. In this study, we investigated this compatibility. Our work shows that sampling with ethylene oxide treated flocked swab reduces by a factor of at least 100 the detection threshold of blood using the Hexagon Obti immunological test.

On the frequency of occurrence of a peculiar polyester fibre type found in blue denim textiles.

In a double murder investigation, the victims were found after a prolonged stay in a drainage canal. In spite of the expectations, fibre examination established a multitude of primary and secondary transferred fibres. One of these fibre types was a colourless polyester fibre possessing a blue coloured molten fibre end. These matched one of the types present in the suspect's blue denim trousers. The aim of this study was to verify the rarity of this peculiar fibre type and more precisely its presence in blue denim textiles. Over five hundred different blue jeans textiles were examined and only one of these presented exactly the same type. The comparison involved microscopy, microspectrophotometry in the visible range and Raman spectroscopy. The results indicate this fibre type is extremely rare in a blue jeans fabrics and that "standard" blue denim should not be disregarded in case work.

Gold-loaded carbon nanoparticles from poly(vinyl alcohol)-b-poly(acrylonitrile) non-shell-cross-linked micelles.

Herein we show that a new amphiphilic poly(vinyl alcohol)-b-poly(acrylonitrile) block copolymer dispersed in water can be easily loaded with gold nanoparticles by addition of chlorauric acid followed by reduction by sodium borohydride. After deposition of the so-loaded micelles onto a silicon wafer, followed by an appropriate thermal treatment, the poly(acrylonitrile) core of the micelles is carbonized, while the poly(vinyl alcohol) shell is completely decomposed and volatilized, leading to gold encapsulated in carbon nanoparticles. The morphology of the micelles is maintained during thermal treatment without requiring shell-cross-linking of the micelles prior to pyrolysis.