Changing Impact Angles: The Mechanics Involved in Blunt Force Cranial Trauma and Their Importance in Investigating Curb-Stomping Cases

After attending this presentation, attendees will better understand how fracture types can differ as a result of blunt force trauma produced by differing angle strikes. This presentation will impact the forensic science community by providing an experimental model that aids in the understanding of fracture mechanics produced when force is applied to the cranium from differing angles. The majority of studies on the infliction of blunt force trauma to the cranium assess only the initial impact site. This method can therefore result in a loss of essential data relating to the circumstances in which the injury was sustained. The goal of this study was to create an experimental model that would provide a more realistic picture of the damage sustained during a violent attack to aid investigators. Twenty adult pig heads (Sus scrofa domesticus) were placed on a solid base, resting on the mandible. The base could be angled so that the impact angle to the skull could be altered for each strike. Using a drop hammer rig, modified with a replica hammer head (modeled after a 16oz claw hammer), each pig head was struck once over the frontal bone from a height of one meter. A total of five angles were assessed in this preliminary study (0°, 9°, 18°, 27°, and 36°), with each angle tested a minimum of three times. It was not possible to strike the frontal region of the pig head at any angle greater than 36°. To monitor the acceleration, timing, and force of each strike, a piezoelectric accelerometer was attached to the drop hammer, with data recorded at a rate of 10,000 scans per second. Following maceration, the fractures present were compared with previously published images and descriptions, with measurements taken of the width length and depth of each depression fracture. It was noted that a number of mandibles had also fractured when struck using a more direct angle (0°, 9°, and 18°). To establish that this was a result of the impact study, a further set of pig heads were radiographed prior to the strikes. A further radiograph following the impact confirmed that the mandibular fractures had caused a transference of the force through the cranium when struck from above. A total of 22 fractures were observed between the cranium and mandible. Depression fractures (n=10) demonstrated a decrease in size as the angle increased and radiating fractures (n=4) were present on angles from 18°. Mandibular fractures (n=8) were only present up to 18° in this study, with the severity ranging from complete break to partial fractures as the angle increased. It was also noted that the angle of the fracture on the mandible differs as the angles increase. Presented here is a pilot study that exhibits the need to further investigate the issues surrounding violent assaults using blunt force trauma, such as bludgeoning with a hammer; however, an unexpected finding was the secondary trauma inflicted to the mandible as a result of resting on the solid base plate, which mimicked the scenario faced by curb-stomping victims. Although the traditional “biting the curb” posture is not exhibited in this experiment, it provides information on how the transference of force can travel through the skull and exhibit in fractures elsewhere. There are increasing numbers of reports in the media of violent crimes involving blunt force trauma taking place that utilize everyday household objects.2 It has also been highlighted in studies that blunt force trauma to the head is one of the most effective methods of murder, but that the weapons most commonly involved are hands and feet, also referred to as human strength. This study is limited by the small sample size, but has provided information that could direct further research into violent assaults using blunt force trauma. It would be beneficial to repeat the study using a larger sample size, bone substitutes to more directly simulate the cranial biomechanics of a human skull, and by modifying the drop hammer to investigate how increasing the surface area impact will affect the results

Gene expression and matrix turnover in overused and damaged tendons

Chronic, painful conditions affecting tendons, frequently known as tendinopathy, are very common types of sporting injury. The tendon extracellular matrix is substantially altered in tendinopathy, and these changes are thought to precede and underlie the clinical condition. The tendon cell response to repeated minor injuries or “overuse” is thought to be a major factor in the development of tendinopathy. Changes in matrix turnover may also be effected by the cellular response to physical load, altering the balance of matrix turnover and changing the structure and composition of the tendon. Matrix turnover is relatively high in tendons exposed to high mechanical demands, such as the supraspinatus and Achilles, and this is thought to represent either a repair or tissue maintenance function. Metalloproteinases are a large family of enzymes capable of degrading all of the tendon matrix components, and these are thought to play a major role in the degradation of matrix during development, adaptation and repair. It is proposed that some metalloproteinase enzymes are required for the health of the tendon, and others may be damaging, leading to degeneration of the tissue. Further research is required to investigate how these enzyme activities are regulated in tendon and altered in tendinopathy. A profile of all the metalloproteinases expressed and active in healthy and degenerate tendon is required and may lead to the development of new drug therapies for these common and debilitating sports injuries

Subjectivity in a context of environmental change: opening new dialogues in mental health research

In a period of unstable experimentation with challenges of globalization of associated risks, and disenchantment with ‘enduring injustice’, we bring forward a consideration of subjectivity to the study of environmental change and mental health. We begin by identifying how mainstream climate change and mental health studies are unable to explain the emergent and co-evolutionary pathways of agency. As a means of freeing these studies of their objective dimensions of linear-causation, we argue in favour of a re-positioning of subjectivity within an appreciation of recognition conflicts and beyond the over-deterministic interpretations of power centres—state, market or religion. We draw on one example of scientific research that was conducted in a region undergoing strong environmental, social and cultural changes, in the state of São Paulo/Brazil, with the aim to open mental health research to new dialogues, to which we contribute with the notion of the ‘pluriversal subject’

Radiation Produces Irreversible Chronic Dysfunction in the Submandibular Glands of the Rat

The exposure to high doses of ionizing radiation during radiotherapy results in severe morphological and functional alterations of the salivary glands, such as xerostomia. In the present study we investigated the chronic effect of a single radiation dose of 15 Gray (Gy) limited to head and neck on rat salivary gland function (salivary secretion and gland mass) and histology. Results indicate that norepinephrine (NE)-induced salivary secretion was reduced significantly at 30, 90, 180 and 365 days after the administration of a single dose of 15 Gy of ionizing radiation compared to non-irradiated animals. The maximal secretory response was reduced by 33% at 30 and 90 days post irradiation. Interestingly, a new fall in the salivary response to NE was observed at 180 days and was maintained at 365 days post irradiation, showing a 75% reduction in the maximal response. The functional fall of the salivary secretion observed at 180 days post irradiation was not only associated with a reduction of gland mass but also to an alteration of the epithelial architecture exhibiting a changed proportion of ducts and acini, loss of eosinophilic secretor granular material, and glandular vacuolization and fibrosis. On the basis of the presented results, we conclude that ionizing radiation produces irreversible and progressive alterations of submandibular gland (SMG) function and morphology that leads to a severe salivary hypo-function

Balmer Filaments in Tycho's Supernova Remnant: An Interplay between Cosmic-ray and Broad-neutral Precursors

We present H alpha spectroscopic observations and detailed modeling of the Balmer filaments in the supernova remnant (SNR) Tycho (SN 1572). We used GH alpha FaS (Galaxy H alpha Fabry-Perot Spectrometer) on the William Herschel Telescope with a 3'.4 x 3'.4 field of view, 0 ''.2 pixel scale, and sigma(instr) = 8.1 km s(-1) resolution at 1 '' seeing for similar to 10. hr, resulting in 82 spatial-spectral bins that resolve the narrow H alpha line in the entire SN 1572 northeastern rim. For the first time, we can therefore mitigate artificial line broadening from unresolved differential motion and probe H alpha emission parameters in varying shock and ambient medium conditions. Broad H alpha line remains unresolved within spectral coverage of 392 km s-1. We employed Bayesian inference to obtain reliable parameter confidence intervals and to quantify the evidence for models with multiple line components. The median H alpha narrow-line (NL) FWHM of all bins and models is W-NL = (54.8 +/- 1.8) km s(-1) at the 95% confidence level, varying within [35, 72] km s(-1) between bins and clearly broadened compared to the intrinsic (thermal) approximate to 20 km s(-1). Possible line splits are accounted for, significant in approximate to 18% of the filament, and presumably due to remaining projection effects. We also find widespread evidence for intermediate-line emission of a broad-neutral precursor, with a median W-IL =(180 +/- 14) km s(-1) (95% confidence). Finally, we present a measurement of the remnant's systemic velocity, V-LSR = -34 km s(-1), and map differential line-of-sight motions. Our results confirm the existence and interplay of shock precursors in Tycho's remnant. In particular, we show that suprathermal NL emission is near-universal in SN 1572, and that, in the absence of an alternative explanation, collisionless SNR shocks constitute a viable acceleration source for Galactic TeV cosmic-ray protons

Human DESC1 serine protease confers tumorigenic properties to MDCK cells and it is upregulated in tumours of different origin

Proteolysis of the extracellular matrix components plays a crucial role in the regulation of the cellular and physiological processes, and different pathologies have been associated with the loss or gain of function of proteolytic enzymes. DESC1 (differentially expressed in squamous cell carcinoma gene 1), a member of the TTSP (type II transmembrane serine protease) family of serine proteases, is an epithelial-specific enzyme that has been found downregulated in squamous cell carcinoma of the head and neck region. We describe new properties of DESC1 suggesting that this protease may be involved in the progression of some type of tumours. Thus, this enzyme hydrolyses some extracellular matrix components, such as fibronectin, gelatin or fibrinogen. Moreover, Madin–Darby canine kidney (MDCK) cells expressing exogenous human DESC1 acquire properties associated with tumour growth such as enhanced motility and an increase of tubular forms in a 3D collagen lattice following HGF treatment. Finally, we generated polyclonal anti-DESC1 antibodies and immunohistochemical analysis in tissues different from head and neck region indicated that this protease was overexpressed in tumours of diverse origins. Taken together, our results suggest that DESC1 could be considered as a potential therapeutic target in some type of tumours

Topical antibiotics as a major contextual hazard toward bacteremia within selective digestive decontamination studies: a meta-analysis

BACKGROUND: Among methods for preventing pneumonia and possibly also bacteremia in intensive care unit (ICU) patients, Selective Digestive Decontamination (SDD) appears most effective within randomized concurrent controlled trials (RCCT’s) although more recent trials have been cluster randomized. However, of the SDD components, whether protocolized parenteral antibiotic prophylaxis (PPAP) is required, and whether the topical antibiotic actually presents a contextual hazard, remain unresolved. The objective here is to compare the bacteremia rates and patterns of isolates in SDD-RCCT’s versus the broader evidence base. METHODS: Bacteremia incidence proportion data were extracted from component (control and intervention) groups decanted from studies investigating antibiotic (SDD) or non-antibiotic methods of VAP prevention and summarized using random effects meta-analysis of study and group level data. A reference category of groups derived from purely observational studies without any prevention method under study provided a benchmark incidence. RESULTS: Within SDD RCCTs, the mean bacteremia incidence among concurrent component groups not exposed to PPAP (27 control; 17.1%; 13.1-22.1% and 12 intervention groups; 16.2%; 9.1-27.3%) is double that of the benchmark bacteremia incidence derived from 39 benchmark groups (8.3; 6.8-10.2%) and also 20 control groups from studies of non-antibiotic methods (7.1%; 4.8 – 10.5). There is a selective increase in coagulase negative staphylococci (CNS) but not in Pseudomonas aeruginosa among bacteremia isolates within control groups of SDD-RCCT’s versus benchmark groups with data available. CONCLUSIONS: The topical antibiotic component of SDD presents a major contextual hazard toward bacteremia against which the PPAP component partially mitigates. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-014-0714-x) contains supplementary material, which is available to authorized users

Functional evolution of ADAMTS genes: Evidence from analyses of phylogeny and gene organization

BACKGROUND: The ADAMTS (A Disintegrin-like and Metalloprotease with Thrombospondin motifs) proteins are a family of metalloproteases with sequence similarity to the ADAM proteases, that contain the thrombospondin type 1 sequence repeat motifs (TSRs) common to extracellular matrix proteins. ADAMTS proteins have recently gained attention with the discovery of their role in a variety of diseases, including tissue and blood disorders, cancer, osteoarthritis, Alzheimer's and the genetic syndromes Weill-Marchesani syndrome (ADAMTS10), thrombotic thrombocytopenic purpura (ADAMTS13), and Ehlers-Danlos syndrome type VIIC (ADAMTS2) in humans and belted white-spotting mutation in mice (ADAMTS20). RESULTS: Phylogenetic analysis and comparison of the exon/intron organization of vertebrate (Homo, Mus, Fugu), chordate (Ciona) and invertebrate (Drosophila and Caenorhabditis) ADAMTS homologs has elucidated the evolutionary relationships of this important gene family, which comprises 19 members in humans. CONCLUSIONS: The evolutionary history of ADAMTS genes in vertebrate genomes has been marked by rampant gene duplication, including a retrotransposition that gave rise to a distinct ADAMTS subfamily (ADAMTS1, -4, -5, -8, -15) that may have distinct aggrecanase and angiogenesis functions