Inconsistency in 9 mm bullets : correlation of jacket thickness to post-impact geometry measured with non-destructive X-ray computed tomography

Fundamental to any ballistic armour standard is the reference projectile to be defeated. Typically, for certification purposes, a consistent and symmetrical bullet geometry is assumed, however variations in bullet jacket dimensions can have far reaching consequences. Traditionally, characteristics and internal dimensions have been analysed by physically sectioning bullets – an approach which is of restricted scope and which precludes subsequent ballistic assessment. The use of a non-destructive X-ray computed tomography (CT) method has been demonstrated and validated Kumar et al., 2011); the authors now apply this technique to correlate bullet impact response with jacket thickness variations. A set of 20 bullets (9 mm DM11) were selected for comparison and an image-based analysis method was employed to map jacket thickness and determine the centre of gravity of each specimen. Both intra- and inter-bullet variations were investigated, with thickness variations of the order of 200 um commonly found along the length of all bullets and angular variations of up to 50 um in some. The bullets were subsequently impacted against a rigid flat plate under controlled conditions (observed on a high-speed video camera) and the resulting deformed projectiles were re-analysed. The results of the experiments demonstrate a marked difference in ballistic performance between bullets from different manufacturers and an asymmetric thinning of the jacket is observed in regions of pre-impact weakness. The conclusions are relevant for future soft armour standards and provide important quantitative data for numerical model correlation and development. The implications of the findings of the work on the reliability and repeatability of the industry standard V50 ballistic test are also discussed

Re-engineering forensic anthropology : new techniques in sharp force trauma analysis

In forensic anthropology the analysis of microscopic tool marks found in skeletal sharp force trauma is a challenging area. Many different imaging methods have been employed to measure cut mark characteristics in aid of developing diagnostic tools for estimating knife type used for these marks. Furthermore numerous experimental methods for creating tool marks for analysis have been used. A novel method for creating, analysing and presenting tool marks using reverse engineering and metrology was investigated. 5 Pig torsos prepared to mimic human anatomy were stabbed using seven different knives. Following chemical defleshing the ribs were micro-CT scanned for the analysis of tool marks left from the knives. Other methods including SEM, Digital microscopy and Laser scanning were also considered. Various geometrical measurements of the cut mark micro-morphology were taken. These measurements were statistically analysed using SPSS. Knife types gave statistically significant different cut mark width, length, wall angle, floor radius and shape (p<0.001). Knife sub-types and individual knives also gave statistically significant differencing in width and shape (p<0.001). Statistical classification of cut marks as either serrated or non-serrated made marks was shown to be 90% if width, length, wall angle and floor radius were accounted for. This indicated that determining knife type quantitatively is possible and could aid criminal investigators with their enquires. 3D models of these cut marks could also be developed for potential use in court for forensic expert testimony

Weapon-wound matching of sharp force trauma to bone – a micro-CT analysis

Nearly 40% of murders in the UK result from sharp force trauma caused by knives. Weapon-wound matching in Forensic anthropology attempts to estimate weapon class from the wound characteristics but few studies have investigated quantitative methods for performing this analysis on the microscopic scale. In this study five cadaveric pig torsos, prepared to mimic human anatomy, were stabbed in the upright position with 12 different knives. Knife dynamics were recorded using a Casio high-speed camera (420fps). Samples were chemically defleshed exposing the regions on the ribs where the knives have made contact, thus marking the bone, so micro-CT can be performed. All samples underwent a pre and post-stab CT scan so that rib marks could be matched to the knife used. Preliminary results show that there is a significant difference between serrated and none serrated cut geometry regardless of knife force or penetration angle. If these results hold true for the larger sample of knives tested within this study (analysis currently in progress) and the significant differences between knives are above noise then, a new technique for statistically estimating knife class from cut marks can be developed. Applications of this in forensic anthropology will aid criminal investigators in their inquiries

Intertwining technique for a system of difference Schroedinger equations and new exactly solvable multichannel potentials

The intertwining operator technique is applied to difference Schroedinger equations with operator-valued coefficients. It is shown that these equations appear naturally when a discrete basis is used for solving a multichannel Schroedinger equation. New families of exactly solvable multichannel Hamiltonians are found

The structure of the hexameric atrazine chlorohydrolase AtzA

Atrazine chlorohydrolase (AtzA) was discovered and purified in the early 1990s from soil that had been exposed to the widely used herbicide atrazine. It was subsequently found that this enzyme catalyzes the first and necessary step in the breakdown of atrazine by the soil organism Pseudomonas sp. strain ADP. Although it has taken 20 years, a crystal structure of the full hexameric form of AtzA has now been obtained. AtzA is less well adapted to its physiological role (i.e. atrazine dechlorination) than the alternative metal-dependent atrazine chlorohydrolase (TrzN), with a substrate-binding pocket that is under considerable strain and for which the substrate is a poor fit

Breeding \u3cem\u3eLotus Australis\u3c/em\u3e Andrews for Low Cyanide Content

Lotus australis Andrews is a native perennial tetraploid legume (2n=4x=28) widely distributed throughout Australia (Figure 1). It is highly variable with 14 botanical varieties reported in the Australian Plant Name Index (http://www.anbg.gov.au). Despite broad adaptation within L. australis no cultivars have been developed for cultivation. One of the main barriers to cultivation is the reported cyanogenic nature of the species (Foulds, 1982), which makes it potentially toxic when plant cyanogenic glycosides are fully hydrolysed to form hydrogen cyanide (HCN). Foulds (1982) also reported that the cyanophoric trait was polymorphic at seedling and adult stages with 12% of plants acyanogenic in some populations. . The Cooperative Research Center for Plant-Based Management of Dryland Salinity, financially supported by Australian Wool Innovation has commenced a breeding program to develop a non-toxic cultivar of L. australis. The selection criterion of the first phase of the breeding programme was for low HCN production. Once this trait is stabilised, forage production and seed yield as well as general plant health will be the main breeding objectives

Functional polymorphisms in the P2X7 receptor gene are associated with stress fracture injury

Context: Military recruits and elite athletes are susceptible to stress fracture injuries. Genetic predisposition has been postulated to have a role in their development. The P2X7 receptor (P2X7R) gene, a key regulator of bone remodelling, is a genetic candidate that may contribute to stress fracture predisposition. Objective: To evaluate the putative contribution of P2X7R to stress fracture injury in two separate cohorts, military personnel and elite athletes. Methods: In 210 Israeli Defence Forces (IDF) military conscripts, stress fracture injury was diagnosed (n=43) based on symptoms and a positive bone scan. In a separate cohort of 518 elite athletes, self-reported medical imaging scan-certified stress fracture injuries were recorded (n=125). Non-stress fracture controls were identified from these cohorts who had a normal bone scan or no history or symptoms of stress fracture injury. Study participants were genotyped for functional SNPs within the P2X7R gene using proprietary fluorescence-based competitive allele-specific PCR assay. Pearson Chi-square (χ2) tests, corrected for multiple comparisons, were used to assess associations in genotype frequencies. Results: The variant allele of P2X7R SNP rs3751143 (Glu496Ala- loss of function) was associated with stress fracture injury, while the variant allele of rs1718119 (Ala348Thr- gain of function) was associated with a reduced occurrence of stress fracture injury in military conscripts (P<0.05). The association of the variant allele of rs3751143 with stress fractures was replicated in elite athletes (P<0.05), whereas the variant allele of rs1718119 was also associated with reduced multiple stress fracture cases in elite athletes (P<0.05). Conclusions: The association between independent P2X7R polymorphisms with stress fracture prevalence supports the role of a genetic predisposition in the development of stress fracture injury

Elevated Mechanical Loading When Young Provides Lifelong Benefits to Cortical Bone Properties in Female Rats Independent of a Surgically Induced Menopause

Exercise that mechanically loads the skeleton is advocated when young to enhance lifelong bone health. Whether the skeletal benefits of elevated loading when young persist into adulthood and after menopause are important questions. This study investigated the influence of a surgically induced menopause in female Sprague-Dawley rats on the lifelong maintenance of the cortical bone benefits of skeletal loading when young. Animals had their right forearm extrinsically loaded 3 d/wk between 4 and 10 weeks of age using the forearm axial compression loading model. Left forearms were internal controls and not loaded. Animals were subsequently detrained (restricted to cage activities) for 94 weeks (until age 2 years), with ovariectomy (OVX) or sham-OVX surgery being performed at 24 weeks of age. Loading enhanced midshaft ulna cortical bone mass, structure, and estimated strength. These benefits persisted lifelong and contributed to loaded ulnas having greater strength after detraining. Loading also had effects on cortical bone quality. The benefits of loading when young were not influenced by a surgically induced menopause because there were no interactions between loading and surgery. However, OVX had independent effects on cortical bone mass, structure, and estimated strength at early postsurgery time points (up to age 58 weeks) and bone quality measures. These data indicate skeletal loading when young had lifelong benefits on cortical bone properties that persisted independent of a surgically induced menopause. This suggests that skeletal loading associated with exercise when young may provide lifelong antifracture benefits by priming the skeleton to offset the cortical bone changes associated with aging and menopause