The effect of the digital printing of fabric on the morphology of passive bloodstains.

Bloodstained fabrics found at crime scenes are likely to have had processing treatments, such as dyeing or printing, but the effect of the treatments on bloodstain morphology is not always considered. In order to study the effect of digital printing on bloodstain morphology, drip stains were created from five impact velocities (1.9-5.4 ms-1) on three different mass per unit areas (88-226 g/m²) of 100% cotton calico which had been digitally printed using reactive dye. Across all three printed fabrics, the bloodstains appeared visually similar, and no correlation was found between the dry bloodstain area and the impact velocity. When comparing the bloodstains on the printed fabric to those which had been created previously on the same fabric in a dyed and not-coloured state, the dry bloodstains on the printed fabric were statistically significantly larger (e.g. for the calico with the lightest mass per unit area, mean dry bloodstain area was 126.6, 64.4 and 44.3 mm² for the printed, dyed and not-coloured fabrics respectively). Examination of the larger bloodstains on the printed calico with the micro computed tomography scanner and scanning electron microscope, suggested that the printing process increased the wettability of the fabric, so the blood could spread more easily on the surface. This allowed the blood to coat the yarns, and wick into them before wicking along the intra-yarn spaces. The results presented in this paper showed that care must be taken when examining bloodstains at crime scenes. Depending on the fabric and the processing of the fabric the size of the blood stains may not increase with impact velocity as wicking may result in a larger bloodstain from a lower velocity. The bloodstain on the penetrated face of the fabric may be larger than on the impacted face and the same fabrics with different processing will produce different blood stain sizes and shapes.

The effect of reactive dyeing of fabric on the morphology of passive bloodstains.

The majority of fabrics at crime scenes have been coloured in some way. The effect of such treatments on resultant bloodstains has not been considered. In this work, horse blood was dropped onto reactively dyed calico fabrics (100% cotton, plain woven) with three different masses of 91 g m-², 171 g m-² and 243 g m-² and the results compared to previous work on the not-coloured calico fabric. Five impact velocities were used from 1.7 ms-1 to 5.4 ms-1. The use of reactive dye increased the thickness (from 0.38 - 0.56 mm to 0.39 - 0.6 mm) and mass per unit area (from 85.1 - 224.6 g/m² to 91 - 243 g/m²) of the calico fabrics. The reactively dyed fabrics had larger bloodstains (e.g. lightest calico 41.2 - 78.6 mm²) compares to the not-coloured fabrics (e.g. lightest calico 21.4 - 67.5 mm²) across all three mass per unit areas. The dyeing of the fabrics altered the intra-yarn spaces to a more optimum size for wicking blood, increasing the ease with which the blood could wick along the yarns in the dyed calico. The amount of wicking varied depending on individual variations within the fabrics and yarns. More variation in dry bloodstain area was seen among dyed calico specimens than for the not-coloured fabric. The amount of wicking which was seen on the dyed calico meant there was no correlation between dry bloodstain area and impact velocity, a correlation which was seen on the medium and heavy not-coloured calico in the previous work.

The ballistic performance of bone when impacted by fragments.

Physical models are required to generate the underlying algorithms that populate computer simulations of the effects of explosive fragmenting devices. These models and simulations are used for understanding weapon performance, designing buildings and optimising personal protective equipment. Previous experimental work has investigated the performance of skin and muscle when subjected to fragmentation threats, but limited evidence exists for the performance of bone when impacted by fragments. In the current work, ballistic testing was conducted using two types of internationally recognised steel fragment simulating projectiles (FSPs): (i) 5.5 mm diameter (0.68 g) ball bearing (BBs) and (ii) 1.10 g chisel nosed (CN). These projectiles were fired at isolated swine ribs at impact velocities between 99 and 1265 m/s. Impact events were recorded using a high-speed camera. Selected specimens were analysed post-impact with plain x-radiographs and micro-CT scanning to determine damage to the bone architecture. Bones were perforated with a kinetic energy density (KED) as low as 0.14 J/mm2. Energy transfer to the bone was greater for the CN FSPs, resulting in increased bone damage and the production of secondary bone fragments. The manner in which the bones failed with faster velocity impacts (> 551 m/s; KED > 6.44 J/mm2) was analogous to the behaviour of a brittle material. Slower velocity impacts (< 323 m/s; KED < 1.49 J/mm2) showed a transition in failure mode with the bone displaying the properties of an elastic, plastic and brittle material at various points during the impact. The study gives critical insight into how bone behaves under these circumstances.

Effect of ballistic impacts on batteries and the potential for injury.

INTRODUCTION: On military operations, ballistic impact damage is possible to lithium ion (Li-ion) batteries worn on the body by military personnel and the potential for exothermic reactions may result in injury. This paper investigated the effect of impact on batteries that might be worn in front or behind body armour. METHODS: Li-ion batteries were subjected to ballistic impact both without and in combination with body armour using 7.62×39 mm ammunition (mean velocity=769 m/s) at charge levels up to 40%. The effect of penetrating impacts on charged batteries was also investigated using an outdoor range. RESULTS: The backface signature due to ballistic impact was reduced by including a battery pack between fabric body armour and an armour plate, however the batteries were crushed and mechanically disrupted. Ballistic impacts on batteries mounted in front of an armour plate resulted in perforation of the batteries. Increases in temperature, fire and toxic gas emission were noted when batteries were penetrated by an impact. CONCLUSIONS: Batteries provided limited ballistic protection disproving the hypothesis that batteries could replace or enhance existing body armour solutions. Ballistic impact of charged batteries could lead to injury due to heat/flame and toxic discharge. It is recommended that batteries need to be carried in a position from which they can be rapidly removed from contact with the body.

Investigating bloodstain dynamics at impact on the technical rear of fabric.

Using high speed video, the impact of blood drops falling at three velocities (1.9, 4.2 and 5.8ms-1) were filmed from both the technical face and for the first time the technical rear of three different mass per unit areas (85.1, 163.5 and 224.6g/m²) of 100% cotton calico. It was seen that there were two stages in the creation of a bloodstain on fabric; the impact dynamics, followed by wicking along the intra-yarn spaces. In the first stage, once the blood impacted the fabric, blood was visible on the technical rear of the fabrics with the medium and lightest mass per unit area within as little as 0.067ms after impact. No blood was visible on the technical rear of the fabric with the heaviest mass per unit area following impact or the medium mass per unit area from 1.7ms-1 impacts. On the technical face of the fabric, the blood drop spread laterally and then receded for 8ms following impact. The dynamics on the technical face were not affected by what was occurring on the technical rear of the fabric. The bloodstain on the technical rear initially only increased until 0.8ms following impact. The increase in technical rear bloodstain area was caused by continued movement of the blood through to the rear of the fabric as the blood drop spread on the technical face. Once the impact dynamics were concluded within 8ms of impact, there was no further change in the bloodstain for the remaining 67ms of high speed video. Following this the blood wicked into and along the yarns, resulting in a dry technical rear bloodstain on all fabrics at all velocities.

The effect of fabric mass per unit area and blood impact velocity on bloodstain morphology.

This paper discusses the effects of thickness, mass per unit area, sett, yarn linear density and twist of calico fabrics (100% cotton, plain woven) on the morphology of passive bloodstains. Horse blood was dropped vertically onto three calico fabrics with different mass per unit areas (85.1 g/m², 163.5 g/m² and 224.6 g/m²). Six different impact velocities were used (1.7 ms-1, 2.9 ms-1, 4.1 ms-1, 4.9 ms-1, 5.1 ms-1 and 5.4 ms-1). The dry bloodstains were largest on the calico with the lightest mass per unit area. The low yarn linear density and large inter-yarn spaces meant that the blood could wick into the yarns from all directions and along the intra-yarn spaces. The calico with the middle mass per unit area had the smallest mean dry bloodstain area for four out of the six velocities. The twist level for this calico was greater than for the calicos with a heavier or lighter mass per unit area. This reduced the amount of wicking which occurred along the yarns due to the tighter yarn structure. The calico with the heaviest mass per unit area had the highest yarn linear density resulting in a thicker fabric, so the blood could not as easily penetrate into the fabric. This resulted in a thicker wet blood layer remaining on the fabric surface, where it gradually wicked vertically into the yarns under gravity. Less wicking along the yarns occurred, resulting in a smaller bloodstain than on the fabric with the lightest mass per unit area. The correlation between impact velocity and mean dry bloodstain area was greater for the calicos with the medium and heaviest mass per unit area than for the calico with the lightest mass per unit area. For the calicos with the medium and heaviest mass per unit area, the distance the blood spread laterally at impact, which increased with the increase in impact velocity, had a greater influence on the dry bloodstain area than the amount of wicking.

Edged weapons awareness.

Edged weapons (sometimes referred to as sharp weapons or blades) are an increasing threat to military personnel, the blue light community (police, ambulance, firefighters, other first responders) and the general public worldwide. The use of edged weapons in criminal and terrorist incidents internationally means the forensic community needs an awareness of the technology of edged weapons, how they are used, the damage (clothing and wounding) that might be caused and any other forensic implications. In this paper, the magnitude of the problem is presented, prior research summarised and implications for forensic investigations discussed.

Preliminary development of a bleeding layer to assess the effect of a ballistic impact on textile damage.

When a person is shot, they are generally wearing clothing which will be damaged by the perforation of the bullet. There are relatively few reports of such textile damage in the literature and the effect of blood on the textile damage observed is not reported. The appearance of textile damage caused by bullet impacts is further compounded by the diverse nature of (i) fabrics used in apparel and (ii) ammunition types. In this work, the effect of blood on textile damage due to ballistic impact was investigated by the development of a specimen that incorporated blood. The specimens were impacted with two types of pistol ammunition that are commonly available (i) 9mm Luger HP (8.03g; Federal Premium® Law Enforcement; jacketed hollow-point) and (ii) .357 Magnum (10.24g; Express® Pistol and Revolver; Remington, R357M3, flat-nose soft-point). The resulting textile damage was compared to that in specimens without a bleeding layer. The interaction of blood with textile damage caused by a bullet-impact affected the appearance of the textile damage and resulted in the dispersion of the bullet wipe. These results are important in the content of evidence examined by a textile damage assessor compared to what might be seen in a typical re-creation event in a laboratory. The use of a bleeding layer in textile damage investigations due to ballistic impact resulted in a more realistic scenario.

Preliminary study into the skeletal injuries sustained to the spine from posterior non-perforating ballistic impacts into body armour.

INTRODUCTION: The aim of this paper was to examine any injuries from posterior behind armour blunt trauma ballistic impacts directly over the spine onto typical hard body armours. Due to the spine being close to the surface of the skin and a lack of any previous specific research into this topic, this study was designed to gain preliminary insight into the mechanisms involved and injuries caused. Pigs were chosen as the closest representative of human spine, tissue and skin, although their spines are deeper under the surface than humans. Baseline spine and ribs shots were conducted to ensure that the study was effective. METHOD: This study used a 65 kg cadaveric pig eviscerated torso and 7.62 NATO ammunition (7.62×51; L2A2; mean velocity=838 m/s, SD=4 m/s) impacting hard body armour plates over the spine. Injuries were inspected, and sections were removed for X-ray and micro-CT assessment. RESULTS: There was no visible soft tissue damage under the impact point on the armour over the spine, and no bony injuries were reported. Baseline rib shots resulted in multiple rib fractures; some showed minimal displacement of the bone. Baseline spine shot resulted in damage across the spine involving spinal cord and bone. CONCLUSION: No injuries were noted from the spinal impacts, and the rib shots resulted in injuries consistent with those previously reported. The anatomical differences between pigs and humans does not preclude that bony injuries could occur in a human from these types of spinal ballistic impacts.

The use of gelatine in wound ballistics research.

Blocks of gelatine are used in both lethality and survivability studies for broadly the same reason, i.e. comparison of ammunition effects using a material that it is assumed represents (some part of) the human body. The gelatine is used to visualise the temporary and permanent wound profiles; elements of which are recognised as providing a reasonable approximation to wounding in humans. One set of researchers aim to improve the lethality of the projectile, and the other to understand the effects of the projectile on the body to improve survivability. Research areas that use gelatine blocks are diverse and include ammunition designers, the medical and forensics communities and designers of ballistic protective equipment (including body armour). This paper aims to provide an overarching review of the use of gelatine for wound ballistics studies; it is not intended to provide an extensive review of wound ballistics as that already exists, e.g. Legal Med 23:21-29, 2016. Key messages are that test variables, projectile type (bullet, fragmentation), impact site on the body and intermediate layers (e.g. clothing, personal protective equipment (PPE)) can affect the resulting wound profiles.

The burden of gunshot wounding of UK military personnel in Iraq and Afghanistan from 2003-14.

INTRODUCTION: Gunshot wounding (GSW) is the second most common mechanism of injury in warfare after explosive injury. The aim of this study was to define the clinical burden of GSW placed on UK forces throughout the recent Iraq and Afghanistan conflicts. METHODS: This study was a retrospective review of data from the UK Military Joint Theatre Trauma Registry (JTTR). A JTTR search identified records within the 12 year period of conflict between 19 Mar 2003 and 27 Oct 2014 of all UK military GSW casualties sustained during the complete timelines of both conflicts. Included cases had their clinical timelines and treatment further examined from time of injury up until discharge from hospital or death. RESULTS: There were 723 casualties identified (177 fatalities, 546 survivors). Median age at the time of injury was 24 years (range 18-46 years), with 99.6% of casualties being male. Most common anatomical locations for injury were the extremities, with 52% of all casualties sustaining extremity GSW, followed by 16% GSW to the head, 15% to the thorax, and 7% to the abdomen. In survivors, the rate of extremity injury was higher at 69%, with head, thorax and abdomen injuries relatively lower at 5%, 11% and 6% respectively. All GSW casualties had a total of 2827 separate injuries catalogued. A total of 545 casualties (523 survivors, 22 fatalities) underwent 2357 recorded surgical procedures, which were carried out over 1455 surgical episodes between admission to a deployed medical facility and subsequent transfer to the Royal Centre for Defence Medicine (RCDM) in the UK. This gave a median of 3 (IQR 2-5) surgical procedures within a median of 2 (IQR 2-3) surgical episodes per casualty. Casualties had a combined length of stay (LoS) of 25 years within a medical facility, with a mean LoS in a deployed facility of 1.9 days and 14 days in RCDM. CONCLUSION: These findings define the massive burden of injury associated with battlefield GSW and underscore the need for further research to both reduce wound incidence and severity of these complex injuries.

Effects of chair vibration on indoor annoyance ratings of sonic booms.

The effects of perceptible whole-body vibrations on annoyance ratings of sonic booms and other impulsive environmental sounds experienced indoors were studied. Fifteen pairs of test subjects made annoyance ratings while seated in a living room environment. There were two chairs, one isolated from floor vibrations and the other not isolated, and every test subject rated all signals in both chairs. Halfway through each test session, subjects changed seats. Subjects who sat in the isolated chair first gave lower mean annoyance ratings in both halves of the test than subjects who sat in the non-isolated chair first. Annoyance predictions from models using both sound and vibration measures were closer to average annoyance ratings than predictions from a model using sound measures alone. Reformulation of the annoyance model revealed that the presence of perceptible vibration is equivalent to increasing acoustic metric Perceived Level by 4.8 dB when calculated on exterior signals and by 5.6 dB when calculated on interior signals.

Do air-gaps behind soft body armour affect protection?

INTRODUCTION: Body armour typically comprises a fabric garment covering the torso combined with hard armour (ceramic/composite). Some users wear only soft armour which provides protection from sharp weapons and pistol ammunition. It is usually recommended that body armour is worn against the body with no air-gaps being present between the wearer and the armour. However, air-gaps can occur in certain situations such as females around the breasts, in badly fitting armour and where manufacturers have incorporated an air-gap claiming improvements in thermophysiological burden. The effect of an air-gap on the ballistic protection and the back face signature (BFS) as a result of a non-perforating ballistic impact was determined. METHODS: Armour panels representative of typical police armour (400x400 mm) were mounted on calibrated Roma Plastilina No 1 and impacted with 9 mm Luger FMJ (9×19 mm; full metal jacket; Dynamit Nobel DM11A1B2) ammunition at 365±10 m/s with a range of air-gaps (0-15 mm). Whether or not the ammunition perforated the armour was noted, the BFS was measured and the incidence of pencilling (a severe, deep and narrow BFS) was identified. RESULTS: For 0° impacts, a critical air-gap size of 10 mm is detrimental to armour performance for the armour/ammunition combination assessed in this work. Specifically, the incidences of pencilling were more common with a 10 mm air-gap and resulted in BFS depth:volume ratios ≥1.0. For impacts at 30° the armour was susceptible to perforation irrespective of air-gap. CONCLUSIONS: This work suggested that an air-gap behind police body armour might result in an increased likelihood of injury. It is recommended that body armour is worn with no air-gap underneath.

Does preliminary optimisation of an anatomically correct skull-brain model using simple simulants produce clinically realistic ballistic injury fracture patterns?

Ballistic head injury remains a significant threat to military personnel. Studying such injuries requires a model that can be used with a military helmet. This paper describes further work on a skull-brain model using skulls made from three different polyurethane plastics and a series of skull 'fills' to simulate brain (3, 5, 7 and 10% gelatine by mass and PermaGel™). The models were subjected to ballistic impact from 7.62 × 39 mm mild steel core bullets. The first part of the work compares the different polyurethanes (mean bullet muzzle velocity of 708 m/s), and the second part compares the different fills (mean bullet muzzle velocity of 680 m/s). The impact events were filmed using high speed cameras. The resulting fracture patterns in the skulls were reviewed and scored by five clinicians experienced in assessing penetrating head injury. In over half of the models, one or more assessors felt aspects of the fracture pattern were close to real injury. Limitations of the model include the skull being manufactured in two parts and the lack of a realistic skin layer. Further work is ongoing to address these.

Angled shots onto body armour using 9†mm ammunition: the effect on potential blunt injury.

INTRODUCTION: Some military specialists wear body armour that is more similar to police armour and provides protection from ammunition fired from pistols. During ballistic testing, these armours are mounted on a standardised type of modelling clay and the back face signature (BFS; depth of depression) formed as a result of the non-perforating impact event on to the armour is measured. This study investigated the effect of impact angle on the BFS and on the deformation of the bullet. METHODS: Two commonly worn types of armour (HG1/A+KR1 and HG1+KR1) were considered that provide protection from pistol ammunition and sharp weapons. Armours were tested against two types of pistol ammunition (9 mm full metal jacket and 9 mm hollow point) at eight different impact angles (0°, 15°, 30°, 45°, 60°, 70°, 75° and 80°). RESULTS: Increased impact angles resulted in smaller BFSs. Impact angle also affected whether bullets were retained in the armour; as the impact angle increased, the probability of a round exiting the side of the armour increased. Bullet deformation was affected by impact angle. CONCLUSIONS: Understanding the deformation of bullets may assist with recreating a shooting incident and interpreting forensic evidence.

Development of a laboratory test for knicker tearing re-creation studies.

False sexual assault and rape claims result in wasted forensic and police resources and stigma for the alleged offender. In this work a laboratory method was developed to (i) recreate the ripping of knickers and (ii) measure the force required to rip the garments. The effect of laundering was considered as a means to mimic age of garment, and the effect of speed of ripping was used as a measure of forcible removal of garments. Whilst laundering resulted in visual damage to the thongs, it did not affect the mechanical properties. Faster test speeds resulted in higher measured forces and increased levels of damage. This may allow comment to be made regarding the level of force used during an attack.

Comparison of porcine thorax to gelatine blocks for wound ballistics studies.

Tissue simulants are typically used in ballistic testing as substitutes for biological tissues. Many simulants have been used, with gelatine amongst the most common. While two concentrations of gelatine (10 and 20 %) have been used extensively, no agreed standard exists for the preparation of either. Comparison of ballistic damage produced in both concentrations is lacking. The damage produced in gelatine is also questioned, with regards to what it would mean for specific areas of living tissue. The aim of the work discussed in this paper was to consider how damage caused by selected pistol and rifle ammunition varied in different simulants. Damage to gelatine blocks 10 and 20 % in concentration were tested with 9 mm Luger (9 × 19 full metal jacket; FMJ) rounds, while damage produced by .223 Remington (5.56 × 45 Federal Premium® Tactical® Bonded®) rounds to porcine thorax sections (skin, underlying tissue, ribs, lungs, ribs, underlying tissue, skin; backed by a block of 10 % gelatine) were compared to 10 and 20 % gelatine blocks. Results from the .223 Remington rifle round, which is one that typically expands on impact, revealed depths of penetration in the thorax arrangement were significantly different to 20 % gelatine, but not 10 % gelatine. The level of damage produced in the simulated thoraxes was smaller in scale to that witnessed in both gelatine concentrations, though greater debris was produced in the thoraxes.

A STING-dependent innate-sensing pathway mediates resistance to corneal HSV-1 infection via upregulation of the antiviral effector tetherin.

Type 1 interferons (IFNs; IFNα/ß) mediate immunological host resistance to numerous viral infections, including herpes simplex virus type 1 (HSV-1). The pathways responsible for IFNα/ß signaling during the innate immune response to acute HSV-1 infection in the cornea are incompletely understood. Using a murine ocular infection model, we hypothesized that the stimulator of IFN genes (STING) mediates resistance to HSV-1 infection at the ocular surface and preserves the structural integrity of this mucosal site. Viral pathogenesis, tissue pathology, and host immune responses during ocular HSV-1 infection were characterized by plaque assay, esthesiometry, pachymetry, immunohistochemistry, flow cytometry, and small interfering RNA transfection in wild-type C57BL/6 (WT), STING-deficient (STING(-/-)), and IFNα/ß receptor-deficient (CD118(-/-)) mice at days 3-5 postinfection. The presence of STING was critical for sustained control of HSV-1 replication in the corneal epithelium and resistance to viral neuroinvasion, but loss of STING had a negligible impact with respect to gross tissue pathology. Auxiliary STING-independent IFNα/ß signaling pathways were responsible for maintenance of corneal integrity. Lymphatic vessels, mast cells, and sensory innervation were compromised in CD118(-/-) mice concurrent with increased tissue edema. STING-dependent signaling led to the upregulation of tetherin, a viral restriction factor we identify is important in containing the spread of HSV-1 in vivo.

The use of micro computed tomography to ascertain the morphology of bloodstains on fabric.

Very little is known about the interactions of blood and fabric and how bloodstains on fabric are formed. Whereas the blood stain size for non-absorbent surfaces depends on impact velocity, previous work has suggested that for fabrics the blood stain size is independent of impact velocity when the drop size is kept constant. Therefore, a greater understanding of the interaction of blood and fabric is required. This paper explores the possibility of using a micro computed tomography (CT) scanner to study bloodstain size and shape throughout fabrics. Two different fabrics were used: 100% cotton rib knit and 100% cotton bull drill. Bloodstains were created by dropping blood droplets from three heights; 500 mm, 1000 mm and 1500 mm. Results from the CT scanner clearly showed the bloodstain shape throughout the fabric. The blood was found to form a diamond shaped stain, with the maximum cross-sectional area 0.3-0.5mm below the surface. The bloodstain morphology depended on both the impact velocity and fabric structure.

Hepatic IGF1 DNA methylation is influenced by gender but not by intrauterine growth restriction in the young lamb.

Intrauterine growth restriction (IUGR) and postnatal catch-up growth confer an increased risk of adult-onset disease. Overnourishment of adolescent ewes generates IUGR in ∼ 50% of lambs, which subsequently exhibit increased fractional growth rates. We investigated putative epigenetic changes underlying this early postnatal phenotype by quantifying gene-specific methylation at cytosine:guanine (CpG) dinucleotides. Hepatic DNA/RNA was extracted from IUGR [eight male (M)/nine female (F)] and normal birth weight (12 M/9 F) lambs. Polymerase chain reaction was performed using primers targeting CpG islands in 10 genes: insulin, growth hormone, insulin-like growth factor (IGF)1, IGF2, H19, insulin receptor, growth hormone receptor, IGF receptors 1 and 2, and the glucocorticoid receptor. Using pyrosequencing, methylation status was determined by quantifying cytosine:thymine ratios at 57 CpG sites. Messenger RNA (mRNA) expression of IGF system genes and plasma IGF1/insulin were determined. DNA methylation was independent of IUGR status but sexual dimorphism in IGF1 methylation was evident (MF (both P<0.001). IGF1 mRNA expression correlated negatively with IGF1 methylation (r=-0.507, P=0.002) and positively with plasma IGF1 (r=0.884, P<0.001). Carcass and empty body weights were greater in males (P=0.002-0.014) and this gender difference in early body conformation was mirrored by sexual dimorphism in hepatic IGF1 DNA methylation, mRNA expression and plasma IGF1 concentrations.