Fundamental Studies into the Chemical and Physical Properties of Latent Fingermarks

This thesis describes physical and chemical investigations performed on latent fingermarks deposited on non-porous surfaces in order to provide the necessary fundamental underpinnings for future fingermark research. Variation of the physical properties over time was investigated using a novel imaging mode of atomic force microscopy. Spatial distribution of fingermark components was investigated using high-resolution vibrational microspectroscopy techniques. Time-course transformation of squalene in fingermarks stored under different storage conditions was examined using liquid chromatography-high-resolution mass spectrometry

Microscopy in forensic science

This chapter examines the use of electron microscopy, atomic force microscopy and other analytical techniques in forensic investigation and research. These tools can be used to enhance examination of human remains and trace evidence to improve understanding of cause of death, victim identification or post mortem interval.A police-designed scenario is used to highlight trace evidence such as glass, gun shot residue and paint. The validity of forensic techniques is discussed, with reference to international standards, repeatability, and false convictions. Ballistic evidence is used to highlight the complexities in evidence interpretation, including manufacturing variability, environmental effects and likelihood ratios.The use of scanning electron microscopy (SEM), atomic force microscopy (AFM) and other techniques in the development of forensic research is showcased, with particular examples from the field of fingerprints. Examples include improvements in the development of fingermarks from difficult surfaces, interaction of evidence types, and added intelligence from the crime scene, such as forensic timeline or gender of perpetrator

Promotion of private sector investment in urban centres as a strategy for economic development of the Mahaweli region

The Mahaweli Ganga Multi-purpose Development scheme is the biggest public investment programme ever conceived and executed in this country. Sri Lanka had to undertake this challenge immediately as a possible alternative, left-over against the imperative issues of keeping the nation fed, the collossal annual drain of foreign exchange stemming from the need to import food and oil-fed energy, acute unemployment and to establish human settlements in the Dry zone to accommodate land less people and to reduce the congestion of densly populated areas in the Wet zone. Thus the vision to re-create a fldurishing modern civilisation comprising all aspects, economic, social, physical and environmental. The achievement of most of the above targets are now being causing the reality in the Mahaweli areas to take place-as scheduled. Of all the planning and development of in irrigation systems, based of settlements, urban centres Systems, and the Hamlets at context public investment has Human settlements on the suggested stand at the top the lowest level. been allocated in continuing hierarchy level in In this two segment viz; (a) agricultural settlement development and (b) service based urban c~ntre development. Though the initial by the government in urban centres it private investment. investment have been to provide necessary appears to be less made available infrastructure attractive for Further, compared to traditional urban centres outside the Mahaweli area it seems that less contr ibut ion of private sector investment takes place in the economic development of the Mahaweli region

An Assessment of Groundwater Quality in the Land Area around the University of Sri Jayewardenepura

The groundwater quality in the land area around the premises of University of Sri Jayewardenepura which belongs to Boralesgamuwa, Gangodawilla and, Nawinna in Colombo district was investigated. The land area was divided in to 4 clusters depending on the population and water samples from 96 randomly selected domestic wells were obtained during the wet season (October-March 2008/2009). Samples were analyzed for 14 water quality parameters, namely pH, temperature, conductivity, turbidity,NO2-, NO3-, total hardness, total iron, TS, DO, COD, BOD, heavy metals (Zn, Mn, Cr and Pb), and total coliform and E.coli using the standard methods specified by SLSI.Results showed that the pH (3.2-6.9) of about 95.8% of the samples were not within the SLS standards while with respect to conductivity (61.2-719 ìS cm-1), total hardness (8.3-233.8 ppm), and NO3- (0.09- 4.0 ppm), samples were within the permissible level. Very few samples showed high turbidity values (0.1-133 NTU), total iron (0-3.12 ppm), and TS (20-1643 ppm). NO2- concentration (0-0.34 ppm) was found to be rather high in the area and also when considering the DO (1.8-8.69 mg O2 dm-3), COD (3.81-60.85 ppm), and BOD (0.41-19.27 mg O2 dm-3) values some of samples were not within the permissible level. Groundwater contamination by Zn (0-0.798 ppm) and Mn (0.016-0.291 ppm) was significant in the area around the university, but all the values were below the permissible level. Cr and Pb were found to be absent in all samples tested.Most of the samples tested showed high MPN numbers (3-1100) exceeding the levels given in SLS standards, the samples obtained from the area around Nawinna dumping site was contaminated with E.coli

Nanomechanical mapping of latent fingermarks: A preliminary investigation into the changes in surface interactions and topography over time

© 2016 Elsevier Ireland Ltd. Crime scene investigations often rely on successful development of latent fingermarks for personal identification. In this context, exploring fundamental properties of latent fingermarks is vital for developing robust and more effective detection techniques. Here in a novel approach, PeakForce quantitative nanomechanical mapping (PF QNM) atomic force microscopy (AFM) has been used to study the variations in surface adhesion and topography of latent fingermark droplets over time. It was found that variation in adhesion was exhibited even across the surface of a single fingermark droplet, suggesting that individual droplets are heterogeneous in chemical composition on the nanoscale. The technique was successfully employed in observing the topographical variation of eccrine droplets, which has not been achieved using other optical microscopy techniques. In addition, the adhesion of fingermark droplets changed significantly as they aged. Propagation of a thin film of material from the fingermark ridges across the furrows, starting immediately after deposition, was captured in real-time, demonstrating the dynamic nature of the deposit. These results will aid in providing a more complete fundamental understanding of latent fingermark residue, allowing the more rational development of new detection techniques, especially those involving nanostructured materials

Analysis of squalene and its transformation by-products in latent fingermarks by ultrahigh-performance liquid chromatography-high resolution accurate mass Orbitrap™ mass spectrometry

Transformation of squalene and its by-products in latent fingermarks over time under different storage conditions (light, dark, and underwater) was examined through ultrahigh-performance liquid chromatography-high resolution accurate mass Orbitrap™ mass spectrometry. Complications of assessing fingermark compositional variation over time using multiple samples with varying initial compositions were elucidated and a more rational approach was successfully demonstrated. Squalene was detected in all fresh natural fingermarks deposited on non-porous surfaces and the amount ranged between 0.20 to 11.32 μg/5 fingertips. A notable difference in the transformation of squalene was observed with different storage conditions, where a dark aquatic environment accelerated degradation of squalene compared to dark but dry conditions. Squalene monohydroperoxide was extremely short-lived in natural deposits while the amount of squalene epoxide was still increasing relative to the initial amount, after ageing under dark and aquatic conditions for up to 7 days. Some oxidation by-products of cholesterol were also tentatively identified, which exhibited a growth over time against their initial concentration under any of the storage condition tested. These by-products, therefore, show potential as biomarkers for targeted visualisation of aged deposits

Analysis of Squalene and Its Transformation By-Products in Latent Fingermarks by Ultrahigh-Pressure Liquid Chromatography-High Resolution Accurate Mass Orbitrap™ Mass Spectrometry

Transformation of squalene and its by-products in fingermarks over time under different storage conditions (light, dark and underwater) was examined through ultrahigh-pressure liquid chromatography high resolution accurate mass Orbitrap™ mass spectrometry. Complications of assessing fingermark compositional variation over time using multiple samples with varying initial compositions were elucidated and a more rational approach was successfully demonstrated. Squalene was detected in all fresh natural fingermarks and the amount ranged between 0.20 to 11.32 μg/5 fingertips. A notable difference in the transformation of squalene was observed with different storage conditions, where a dark aquatic environment accelerated degradation of squalene compared to dark but dry conditions. Squalene monohydroperoxide was extremely short-lived in natural deposits while the amount of squalene epoxide was still increasing relative to the initial amount, after ageing under dark and aquatic conditions for up to 7 days. Some oxidation by-products of cholesterol were also tentatively identified, which exhibited a growth over time against their initial concentration under any of the storage condition tested. These by-products, therefore, show potential as biomarkers for targeted visualisation of aged deposits.</p

Evaluation of a solvent-free p-dimethylaminobenzaldehyde method for fingermark visualisation with a low cost light source suitable for remote locations

The guidelines set forth by the International Fingerprint Research Group were used to plan and conduct the evaluation of a dry contact p-dimethylaminobenzaldehyde (DMAB) approach to the treatment of latent fingermark deposits on porous substrates. Extensive investigations into the development method and its subsequent use across a range of conditions and substrates showed that the dry contact DMAB method is not as sensitive as the recommended ninhydrin techniques. It was found that these guidelines provided a practicable framework for the implementation of method optimisation and comparison studies. Illumination in the form of a cheap LED light source was shown to be a promising alternative to the much more expensive Rofin Polilight®, especially in teaching or remote environments

Revealing the elemental distribution within latent fingermarks using synchrotron sourced x-ray fluorescence microscopy

Copyright © 2019 American Chemical Society. Fingermarks are an important form of crime-scene trace evidence; however, their usefulness may be hampered by a variation in response or a lack of robustness in detection methods. Understanding the chemical composition and distribution within fingermarks may help explain variation in latent fingermark detection with existing methods and identify new strategies to increase detection capabilities. The majority of research in the literature describes investigation of organic components of fingermark residue, leaving the elemental distribution less well understood. The relative scarcity of information regarding the elemental distribution within fingermarks is in part due to previous unavailability of direct, micron resolution elemental mapping techniques. This capability is now provided at third generation synchrotron light sources, where X-ray fluorescence microscopy (XFM) provides micron or submicron spatial resolution and direct detection with sub-μM detection limits. XFM has been applied in this study to reveal the distribution of inorganic components within fingermark residue, including endogenous trace metals (Fe, Cu, Zn), diffusible ions (Cl-, K+, Ca2+), and exogeneous metals (Ni, Ti, Bi). This study incorporated a multimodal approach using XFM and infrared microspectroscopy analyses to demonstrate colocalization of endogenous metals within the hydrophilic organic components of fingermark residue. Additional experiments were then undertaken to investigate how sources of exogenous metals (e.g., coins and cosmetics) may be transferred to, and distributed within, latent fingermarks. Lastly, this study reports a preliminary assessment of how environmental factors such as exposure to aqueous environments may affect elemental distribution within fingermarks. Taken together, the results of this study advance our current understanding of fingermark composition and its spatial distribution of chemical components and may help explain detection variation observed during detection of fingermarks using standard forensic protocols

Revealing the spatial distribution of chemical species within latent fingermarks using vibrational spectroscopy

Latent fingermarks are an important form of crime-scene trace evidence and their usefulness may be increased by a greater understanding of the effect of chemical distribution within fingermarks on the sensitivity and robustness of fingermark detection methods. Specifically, the relative abundance and micro-distribution of sebaceous (lipophilic) and eccrine (hydrophilic) material in fingermarks have long been debated in the field, yet direct visualisation of relative abundance and micro-distribution was rarely achieved. Such a visualisation is nonetheless essential to provide explanations for the variation in reproducibility or robustness of latent fingermark detection with existing methods, and to identify new strategies to increase detection capabilities. In this investigation, we have used SR-ATR-FTIR and confocal Raman microscopy to probe the spatial micro-distribution of the sebaceous and eccrine chemical components within latent fingermarks, deposited on non-porous surfaces. It was determined that fingermarks exhibit a complex spatial distribution, influenced by the ratio of lipophilic to aqueous components, and to a first approximation resemble a water-in-oil or oil-in-water emulsion. Detection of a substantial lipid component in "eccrine enriched fingermarks" (wherein hands are washed to remove lipids) is noteworthy, as it provides a potential explanation for several scenarios of unexpected fingermark detection using methods previously thought unsuitable for "eccrine deposits". Furthermore, the pronounced distribution of lipids observed in natural fingermark deposits was intriguing and agrees with recent discussion in this research field that natural fingermarks contain a much higher lipid content than previously thought