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1.
Am J Forensic Med Pathol ; 34(3): 185-94, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23574874

RESUMO

During his lifetime, Sir Bernard Spilsbury was referred to as the "father of forensic medicine." He became a household name as a result of several famous cases. Several articles have been written about his life and work, but an objective assessment has proved difficult because of the lack of available material that Spilsbury himself produced. His main legacy has been a series of case cards, but for many years these were unavailable to the researcher. In 2008, a collection of some 4000 of Spilsbury's case cards was bought by The Wellcome Library in London and therefore entered the public domain. In this article, we report our study of 650 of these cards. We discuss trends in Spilsbury's work and several specific cases in more detail. These cards allow an objective view to be taken of Spilsbury's everyday work, and we feel that some reappraisal of his legacy is now timely.


Assuntos
Autopsia/história , Medicina Legal/história , História do Século XX , Humanos , Bibliotecas Médicas , Londres , Prontuários Médicos
2.
J Forensic Sci ; 58(2): 495-9, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23278849

RESUMO

Fire investigation is a challenging area for the forensic investigator. The aim of this work was to use spectral changes to paint samples to estimate the temperatures to which a paint has been heated. Five paint samples (one clay paint, two car paints, one metallic paint, and one matt emulsion) have been fully characterized by a combination of attenuated total reflectance Fourier transform infrared (ATR-IR), Raman, X-ray fluorescence spectroscopy and powder X-ray diffraction. The thermal decomposition of these paints has been investigated by means of ATR-IR and thermal gravimetric analysis. Clear temperature markers are observed in the ATR-IR spectra namely: loss of ν(C = O) band, >300°C; appearance of water bands on cooling, >500°C; alterations to ν(Si-O) bands due to dehydration of silicate clays, >700°C; diminution of ν(CO3 ) and δ(CO3 ) modes of CaCO3 , >950°C. We suggest the possible use of portable ATR-IR for nondestructive, in situ analysis of paints.

3.
J Forensic Sci ; 58(2): 508-12, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23316682

RESUMO

We have carried out experiments to investigate the aging of latent fingerprints deposited on black PVC over a period of 4-15 weeks. A thumbprint was used in each case and before deposition of the print the donor rubbed their thumb around their nose to add sebaceous deposits. We have studied the effect of heat, light, and moisture and we find that moisture is the most significant factor in the degradation of the latent print. We have attempted to enhance these latent prints by dusting with valine powder or powders composed of valine mixed with gold or red fluorescent commercial fingerprint powders. To make a direct comparison between "treated" and "untreated" prints, the prints were cut in half with one-half being "treated" and one-half not. Our studies show the best results being obtained when powders of valine and red fluorescent powders are applied prior to cyanoacrylate fuming.

4.
J Virol ; 85(11): 5524-31, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21450831

RESUMO

The molecular mechanism for packaging of the adenovirus (Ad) genome into the capsid is likely similar to that of DNA bacteriophages and herpesviruses-the insertion of viral DNA through a portal structure into a preformed prohead driven by an ATP-hydrolyzing molecular machine. It is speculated that the IVa2 protein of adenovirus is the ATPase providing the power stroke of the packaging machinery. Purified IVa2 binds ATP in vitro and, along with a second Ad protein, the L4 22-kilodalton protein (L4-22K), binds specifically to sequences in the Ad genome that are essential for packaging. The efficiency of binding of these proteins in vitro was correlated with the efficiency of packaging in vivo. By utilizing a virus unable to express IVa2, pm8002, it was reported that IVa2 plays a role in assembly of the empty virion. We wanted to address the question of whether the ATP binding, and hence the putative ATPase activity, of IVa2 was required for its role in virus assembly. Our results show that ATPase activity was not required for the assembly of empty virus particles. In addition, we present evidence that particles were assembled in the absence of IVa2 by using two viruses null for IVa2-a deletion mutant virus, ΔIVa2, and the previously described mutant virus, pm8002. Empty virus particles produced by these IVa2 mutant viruses did not contain detectable viral DNA. We conclude that the major role of IVa2 is in viral DNA packaging. A characterization of the empty particles obtained from the IVa2 mutant viruses compared to wild-type empty particles is presented.


Assuntos
Adenoviridae/fisiologia , Técnicas de Inativação de Genes , Proteínas Virais/genética , Montagem de Vírus , Adenoviridae/genética , DNA Viral/metabolismo , Virossomos/metabolismo
5.
Phys Chem Chem Phys ; 11(40): 9259-67, 2009 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-19812847

RESUMO

Matrix isolation IR spectroscopy has been used to study the vacuum pyrolysis of 1,1,3,3-tetramethyldisiloxane (L1), 1,1,3,3,5,5-hexamethyltrisiloxane (L2) and 3H,5H-octamethyltetrasiloxane (L3) at ca. 1000 K in a flow reactor at low pressures. The hydrocarbons CH3, CH4, C2H2, C2H4, and C2H6 were observed as prominent pyrolysis products in all three systems, and amongst the weaker features are bands arising from the methylsilanes Me2SiH2 (for L1 and L2) and Me3SiH (for L3). The fundamental of SiO was also observed very weakly. By use of quantum chemical calculations combined with earlier kinetic models, mechanisms have been proposed involving the intermediacy of silanones Me2Si=O and MeSiH=O. Model calculations on the decomposition pathways of H3SiOSiH3 and H3SiOSiH2OSiH3 show that silanone elimination is favoured over silylene extrusion.

6.
Artigo em Inglês | MEDLINE | ID: mdl-19268629

RESUMO

Samples taken from middens at the Neolithic site of Catalhöyük in Turkey have been analysed using IR spectroscopy backed up by powder XRD and SEM-EDX. Microcomponents studied include fossil hackberries (providing evidence of ancient diet and seasonality), mineral nodules (providing evidence of post-depositional change) and phytoliths (mineralised plant cells, providing evidence of usage of plant species). Finely laminated ashy deposits have also been investigated allowing chemical and mineralogical variations to be explored. It is found that many layers which appear visually to be quite distinctive have, in fact, very similar mineralogy.


Assuntos
Arqueologia/métodos , Fósseis , Espectrometria por Raios X/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Resíduos/análise , Difração de Raios X/métodos , Culinária , Minerais/análise , Fatores de Tempo , Turquia , Ulmaceae/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-18952494

RESUMO

A range of archaeological samples have been examined using FT-IR spectroscopy. These include suspected coprolite samples from the Neolithic site of Catalhöyük in Turkey, pottery samples from the Roman site of Silchester, UK and the Bronze Age site of Gatas, Spain and unidentified black residues on pottery sherds from the Roman sites of Springhead and Cambourne, UK. For coprolite samples the aim of FT-IR analysis is identification. Identification of coprolites in the field is based on their distinct orange colour; however, such visual identifications can often be misleading due to their similarity with deposits such as ochre and clay. For pottery the aim is to screen those samples that might contain high levels of organic residues which would be suitable for GC-MS analysis. The experiments have shown coprolites to have distinctive spectra, containing strong peaks from calcite, phosphate and quartz; the presence of phosphorus may be confirmed by SEM-EDX analysis. Pottery containing organic residues of plant and animal origin has also been shown to generally display strong phosphate peaks. FT-IR has distinguished between organic resin and non-organic compositions for the black residues, with differences also being seen between organic samples that have the same physical appearance. Further analysis by GC-MS has confirmed the identification of the coprolites through the presence of coprostanol and bile acids, and shows that the majority of organic pottery residues are either fatty acids or mono- or di-acylglycerols from foodstuffs, or triterpenoid resin compounds exposed to high temperatures. One suspected resin sample was shown to contain no organic residues, and it is seen that resin samples with similar physical appearances have different chemical compositions. FT-IR is proposed as a quick and cheap method of screening archaeological samples before subjecting them to the more expensive and time-consuming method of GC-MS. This will eliminate inorganic samples such as clays and ochre from GC-MS analysis, and will screen those samples which are most likely to have a high concentration of preserved organic residues.


Assuntos
Arqueologia , Compostos Orgânicos/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Silicatos de Alumínio/análise , Argila , Cromatografia Gasosa-Espectrometria de Massas , Resinas Sintéticas/análise , Espectrofotometria Infravermelho , Reino Unido
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 71(3): 854-61, 2008 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-18406198

RESUMO

Mineralised organic remains (including apple pips and cereal grains) collected during the ongoing excavations of Insula IX at the Roman town of Silchester, Hampshire have been analysed by a combination of SEM-EDX, powder XRD and IR spectroscopy. The experiments included mapping experiments using spatially resolved versions of each technique. IR and powder XRD mapping have been carried out utilising the synchrotron source at The Daresbury Laboratory on stations 11.1 and 9.6. It is concluded that these samples are preserved by rapid mineralisation in the carbonate-substituted calcium phosphate mineral, dahllite. The rapid mineralisation leads to excellent preservation of the samples and a small crystal size. The value of IR spectroscopy in studying materials like this where the crystal size is small is demonstrated. A comparison is made between the excellent preservation seen in this context and the much poorer preservation of mineralised remains seen in Context 5276 or Cesspit 5251. Comments on the possible mechanism of mineralisation of these samples are made.


Assuntos
Fósseis , Animais , Arqueologia , Microanálise por Sonda Eletrônica , História Antiga , Itália , Microscopia Eletrônica de Varredura , Minerais/análise , Compostos Orgânicos/análise , Difração de Pó , Eliminação de Resíduos/história , Espectrofotometria Infravermelho
9.
J Forensic Sci ; 61(4): 1100-6, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27364294

RESUMO

A method has been developed for the visualization of latent fingerprints on fabrics, which is based upon cyanoacrylate (superglue) fuming followed by imaging using an infrared microscope. Results show that imaging on smooth, shiny fabrics such as polyester, silk, nylon, and acetate of different colors and patterns can give an improvement over existing enhancement methods. Results for cotton and polycotton were less successful and it is thought this may be due a combination of the presence of the carbonyl functional group in these fabrics as well as their absorbency to fingerprint sweat. The carbonyl peak (1700 cm(-1) ) provided the optimum spectroscopic feature to map and image a fingerprint. Comparisons between infrared mapping at a specific frequency range and principal component analysis showed that improved imaging was obtained with principal component analysis.

10.
Spectrochim Acta A Mol Biomol Spectrosc ; 62(4-5): 1131-9, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15953760

RESUMO

Reaction of single crystals of benzoic and trans-cinnamic acids with 200 Torr pressure of ammonia gas in a sealed glass bulb at 20 degrees C generates the corresponding ammonium salts; there is no sign of any 1:2 adduct as has been reported previously for related systems. Isotopic substitution using ND3 has been used to aid identification of the products. Adipic acid likewise reacts with NH3 gas to form a product in which ammonium salts are formed at both carboxylic acid groups. Reaction of 0.5 Torr pressure of NO2 gas with single crystals of 9-methylanthracene and 9-anthracenemethanol in a flow system generates nitrated products where the nitro group appears to be attached at the 10-position, i.e. the position trans to the methyl or methoxy substituent on the central ring. Isotopic substitution using 15NO2 has been used to confirm the identity of the bands arising from the coordinated NO2 group. The products formed when single crystals of hydantoin are reacted with NO2 gas under similar conditions depend on the temperature of the reaction. At 20 degrees C, a nitrated product is formed, but at 65 degrees C this gives way to a product containing no nitro groups. The findings show the general applicability of infrared microspectroscopy to a study of gas-solid reactions of organic single crystals.


Assuntos
Amônia/química , Gases/química , Dióxido de Nitrogênio/química , Antracenos , Ácidos Carboxílicos , Cristalização , Hidantoínas , Espectrofotometria Infravermelho
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 61(1-2): 233-41, 2005 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-15556445

RESUMO

Three ochre samples (A (orange-red in colour), B (red) and C (purple)) from Clearwell Caves, (Gloucestershire, UK) have been examined using an integrated analytical methodology based on the techniques of IR and diffuse reflectance UV-visible-NIR spectroscopy, X-ray diffraction, elemental analysis by ICP-AES and particle size analysis. It is shown that the chromophore in each case is haematite. The differences in colour may be accounted for by (i) different mineralogical and chemical composition in the case of the orange ochre, where higher levels of dolomite and copper are seen and (ii) an unusual particle size distribution in the case of the purple ochre. When the purple ochre was ground to give the same particle size distribution as the red ochre then the colours of the two samples became indistinguishable. An analysis has now been completed of a range of ochre samples with colours from yellow to purple from the important site of Clearwell Caves.


Assuntos
Pigmentos Biológicos/química , Carbonato de Cálcio/química , Cor , Difusão , Compostos Férricos/química , Íons/química , Magnésio/química , Metais/química , Tamanho da Partícula , Análise Espectral , Reino Unido , Difração de Raios X
12.
Artigo em Inglês | MEDLINE | ID: mdl-12524133

RESUMO

Infrared and Raman microspectroscopy have been used to follow the photodimerisation reactions of single crystals, the alpha- and beta-forms of trans-cinnamic acid. This approach allows the starting materials and products-alpha-truxillic acid that has Ci symmetry and beta-truxinic acid, which has Cs symmetry-to be identified. It also allows the topotactic nature of the reaction to be confirmed. Attempts to produce the poorly-defined unreactive gamma-form of trans-cinnamic acid resulted only in a mixture of the alpha- and beta-forms. The findings suggest a wide role for these spectroscopic methods in monitoring solid-state organic reactions.


Assuntos
Cinamatos/química , Cristalização , Dimerização , Fotoquímica , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Estereoisomerismo
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 60(5): 1179-88, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15084337

RESUMO

Ochre samples excavated from the neolithic site at Catalhöyük, Turkey have been compared with "native" ochres from Clearwell Caves, UK using infrared spectroscopy backed up by Raman spectroscopy, scanning electron microscopy (with energy-dispersive X-rays (EDX) analysis), powder X-ray diffraction, diffuse reflection UV-Vis and atomic absorption spectroscopies. For the Clearwell Caves ochres, which range in colour from yellow-orange to red-brown, it is shown that the colour is related to the nature of the chromophore present and not to any differences in particle size. The darker red ochres contain predominantly haematite while the yellow ochre contains only goethite. The ochres from Catalhöyük contain only about one-twentieth of the levels of iron found in the Clearwell Caves ochres. The iron oxide pigment (haematite in all cases studied here) has been mixed with a soft lime plaster which also contains calcite and silicate (clay) minerals.


Assuntos
Técnicas de Química Analítica/métodos , Microscopia Eletrônica de Varredura/métodos , Espectrofotometria Infravermelho/métodos , Espectrofotometria/métodos , Análise Espectral Raman/métodos , Difração de Raios X/métodos , Compostos Férricos/química , Sedimentos Geológicos , Minerais , Raios Ultravioleta , Reino Unido
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 58(5): 959-65, 2002 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11942402

RESUMO

The mineralogy of 11 concretions from the Bronze Age settlement horizons at Brean Down near Weston-super-Mare, Somerset, UK, has been examined by infrared spectroscopy. The concretions are found to contain calcite and apatite and, in some cases, quartz. Four further concretions from the later Iron Age Meare Village, soil samples from Brean Down and mineralised samples of known faecal origin from a cesspit within the Tudor Merchant's house in Tenby have been similarly examined. It is found that all samples contain calcite, but only the concretions and the Tenby cesspit samples contain apatite. None of the soil samples contain apatite, although these are relatively high in quartz. This suggests that the concretions are coprolites and that the apatite has a biological origin in small bone fragments. The infrared study is backed up by scanning electron microscopy which confirms the presence of phosphorus in the coprolite samples and shows a morphology suggestive of the presence of bone fragments; it is likely, therefore, that the coprolites result from a carnivore--most probably from dogs. The findings show the usefulness of infrared spectroscopy for the rapid identification of mineralised coprolitic material from archaeological sites.


Assuntos
Apatitas/análise , Espectrofotometria Infravermelho/métodos , Animais , Arqueologia , Osso e Ossos/química , Carbonato de Cálcio/análise , Bovinos , Cães , Fósseis , Humanos , Microscopia Eletrônica de Varredura/métodos , Paleontologia , Quartzo/análise , Solo , Reino Unido
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 133: 326-34, 2014 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-24956558

RESUMO

Wall plaster sequences from the Neolithic town of Çatalhöyük have been analysed and compared to three types of natural sediment found in the vicinity of the site, using a range of analytical techniques. Block samples containing the plaster sequences were removed from the walls of several different buildings on the East Mound. Sub-samples were examined by IR spectroscopy, X-ray diffraction and X-ray fluorescence to determine the overall mineralogical and elemental composition, whilst thin sections were studied using optical polarising microscopy, IR Microscopy and Environmental Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results of this study have shown that there are two types of wall plaster found in the sequences and that the sediments used to produce these were obtained from at least two distinct sources. In particular, the presence of clay, calcite and magnesian calcite in the foundation plasters suggested that these were prepared predominantly from a marl source. On the other hand, the finishing plasters were found to contain dolomite with a small amount of clay and no calcite, revealing that softlime was used in their preparation. Whilst marl is located directly below and around Çatalhöyük, the nearest source of softlime is 6.5km away, an indication that the latter was important to the Neolithic people, possibly due to the whiter colour (5Y 8/1) of this sediment. Furthermore, the same two plaster types were found on each wall of Building 49, the main building studied in this research, and in all five buildings investigated, suggesting that the use of these sources was an established practice for the inhabitants of several different households across the site.


Assuntos
Arqueologia/métodos , Materiais de Construção/análise , Materiais de Construção/história , Sedimentos Geológicos/análise , Minerais/análise , Silicatos de Alumínio/análise , Silicatos de Alumínio/história , Carbonato de Cálcio/análise , Carbonato de Cálcio/história , Argila , História Antiga , Magnésio/análise , Magnésio/história , Microscopia Eletrônica de Varredura/métodos , Microscopia de Polarização/métodos , Minerais/história , Espectrometria por Raios X/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Turquia , Difração de Raios X/métodos
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 118: 1158-63, 2014 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-24176248

RESUMO

Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm(-1) arising from νasym (CO3(2-)) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ν(OH) (ca. 3500 cm(-1)), ν(C-H) (ca. 2900 cm(-1)) and ν(C=O) (ca. 1750 cm(-1)) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper.


Assuntos
Tinta , Papel , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Inglaterra
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 131: 373-83, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24835941

RESUMO

Samples containing red pigment have been collected from two different archaeological sites dating to the Neolithic (Çatalhöyük in Turkey and Sheikh-e Abad in Iran) and have been analysed by a range of techniques. Sub-samples were examined by IR spectroscopy and X-ray diffraction, whilst thin sections were studied using optical polarising microscopy, synchrotron based IR microscopy and environmental scanning electron microscopy with energy dispersive X-ray analysis. Thin layers of red paint in a wall painting from Çatalhöyük were found to contain ochre (hematite and clay) as well as an unexpected component, grains of red and colourless obsidian, which have not been identified in any previous studies of the wall paintings at Çatalhöyük. These small grains of obsidian may have improved the reflective properties of the paint and made the artwork more vivid in the darkness of the buildings. Analysis of a roughly shaped ball of red sediment found on a possible working surface at Sheikh-e Abad revealed that the cause of the red colouring was the mineral hematite, which was probably from a source of terra rossa sediment in the local area. The results of this work suggest it is unlikely that this had been altered by the Neolithic people through mixing with other minerals.


Assuntos
Corantes/análise , Pintura/análise , Pinturas/história , Silicatos de Alumínio/análise , Arqueologia , Argila , Corantes/história , Compostos Férricos/análise , História Antiga , Irã (Geográfico) , Microscopia de Polarização , Pintura/história , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Síncrotrons , Turquia , Difração de Raios X
18.
J Forensic Sci ; 59(5): 1368-71, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25182300

RESUMO

We have studied the degradation of sebaceous fingerprints on brass surfaces using silver electroless deposition (SED) as a visualization technique. We have stored fingerprints on brass squares either (i) in a locked dark cupboard or (ii) in glass-filtered natural daylight for periods of 3 h, 24 h, 1 week, 3 weeks, and 6 weeks. We find that fingerprints on brass surfaces degrade much more rapidly when kept in the light than they do under dark conditions with a much higher proportion of high-quality prints found after 3 or 6 weeks of aging when stored in the dark. This process is more marked than for similar fingerprints on black PVC surfaces. Identifiable prints can be achieved on brass surfaces using both SED and cyanoacrylate fuming (CFM). SED is quick and straightforward to perform. CFM is more time-consuming but is versatile and can be applied to a wider range of metal surfaces than SED, for example brass surfaces which have been coated by a lacquer.

19.
Artigo em Inglês | MEDLINE | ID: mdl-22029967

RESUMO

We have carried out a thorough mineralogical analysis of 16 pottery samples from the Lapita site of Bourwera in Fiji, using micromorphological techniques with optical and polarising microscopes. While the overall mineralogy of all of the samples is similar the samples clearly divide into two groups, namely those with or without the mineral calcite. Our findings are backed up by chemical analysis using SEM-EDX and FTIR. SEM-EDX shows the clear presence of inclusions of calcite in some of the samples; FTIR shows bands arising from calcite in these samples. The study suggests that it is likely that more than one clay source was used for production of this pottery, but that most of the pottery comes from a single source. This finding is in line with previous studies which suggest some trading of pottery between the Fijian islands but a single source of clay for most of the pottery found at Bouwera. We found no evidence for the destruction of CaCO(3) by heating upon production of the pottery in line with the known technology of the Lapita people who produced earthenware pottery but not high temperature ceramics.


Assuntos
Cerâmica/química , Minerais/análise , Carbonato de Cálcio/análise , Fiji , Microscopia de Polarização , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier
20.
J Forensic Sci ; 55(3): 753-6, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20345804

RESUMO

The collection efficiency of two widely used gunshot residue (GSR) collection techniques-carbon-coated adhesive stubs and alcohol swabs-has been compared by counting the number of characteristic GSR particles collected from the firing hand of a shooter after firing one round. Samples were analyzed with both scanning electron microscopy and energy dispersive X-rays by an experienced GSR analyst, and the number of particles on each sample containing Pb, Ba, and Sb counted. The adhesive stubs showed a greater collection efficiency as all 24 samples gave positive results for GSR particles whereas the swabs gave only positive results for half of the 24 samples. Results showed a statistically significant collection efficiency for the stub collection method and likely reasons for this are considered.

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