A novel hypothesis for the formation of conoidal projectile wounds in sandwich bones

When perforated by a projectile, sandwich bones typically exhibit wounds with a distinct conoidal morphology that is widely utilised both in wound diagnosis and trajectory determinations. However, the dynamic fracture mechanisms underlying this intriguing wound type have yet to be experimentally verified. The most frequently quoted hypothesis for their formation, plug and spall, is difficult to reconcile with the conoidal morphology exhibited by such wounds. The present article carries out a high-speed videographic and micro-computerised tomographic (μ-CT) analysis of perpendicularly produced projectile wounds induced from 139.15 to 896.84 metres per second (m/s) in pig scapulae. Fundamental data on energy absorption, wound shape and bevel symmetry are presented. Cross-sectional fracture morphology revealed by μ-CT raises the novel hypothesis that tensile stresses induced by the projectile in the outer cortex elicit cone crack formation and that this cone crack then propagates catastrophically through the entire sandwich structure. This process results in the momentary formation of a bioceramic conoid, a conoidal volume of bone consisting of all three sandwich bone layers separated from the parent bone by the internal bevel. Fragmentation of the separated volume leaves the conoidal wound behind as its counterpart. The significance of this hypothesis in terms of differential diagnosis and interpretation of bevel shape is discussed

Figure of Merit Characteristics Compared to Engineering Parameters

Current NASA lunar architecture calls for permanent human habitation of the moon by the year 2020. Due to the expense of delivering materials into orbit, technologies are being developed to use lunar regolith for building and as a material resource for fabrication, oxygen production, and other needs. Additionally, constant exposure to the finest size fraction of lunar regolith may present hazards to human health. Towards developing these technologies and mitigating hazards, lunar regolith simulants are becoming an increasingly important part of the development paradigm

Efficient determination of thermodynamic properties from a single simulation

A method for calculating the density of states of a system directly from its trajectory in phase space is described. As a specific example, the method is applied to the Monte Carlo simulation of a two‐dimensional Ising model. The energy distribution function is calculated from the density of states and the associated Helmholtz free energy per spin is calculated for various system sizes and temperatures and shown to be in excellent agreement with the exact results.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69798/2/JCPSA6-99-10-7993-1.pd

An ABC transporter containing a forkhead-associated domain interacts with a serine-threonine protein kinase and is required for growth of Mycobacterium tuberculosis in mice

Forkhead-associated (FHA) domains are modular phosphopeptide recognition motifs with a striking preference for phosphothreonine-containing epitopes. FHA domains have been best characterized in eukaryotic signaling pathways but have been identified in six proteins in Mycobacterium tuberculosis, the causative organism of tuberculosis. One of these, coded by gene Rv1747, is an ABC transporter and the only one to contain two such modules. A deletion mutant of Rv1747 is attenuated in a mouse intravenous injection model of tuberculosis where the bacterial load of the mutant is 10-fold lower than that of the wild type in both lungs and spleen. In addition, growth of the mutant in mouse bone marrow-derived macrophages and dendritic cells is significantly impaired. In contrast, growth of this mutant in vitro was indistinguishable from that of the wild type. The mutant phenotype was lost when the mutation was complemented by the wild-type allele, confirming that it was due to mutation of Rv1747. Using yeast two-hybrid analysis, we have shown that the Rv1747 protein interacts with the serine-threonine protein kinase PknF. This interaction appears to be phospho-dependent since it is abrogated in a kinase-dead mutant and by mutations in the presumed activation loop of PknF and in the first FHA domain of Rv1747. These results demonstrate that the protein coded by Rv1747 is required for normal virulent infection by M. tuberculosis in mice and, since it interacts with a serine-threonine protein kinase in a kinase-dependent manner, indicate that it forms part of an important phospho-dependent signaling pathway

Injection of Oort Cloud comets: the fundamental role of stellar perturbations

Celestial Mechanics and Dynamical Astronomy, 102, pp. 111-132, http://dx.doi.org./10.1007/s10569-008-9140-yInternational audienc

Failure of conventional retrograde cystography to detect bladder ruptures in pelvic trauma

Conventional retrograde cystography is often used to investigate patients with suspected bladder ruptures in pelvic trauma. Clinical indicators suggestive of a rupture include haematuria and suprapubic tenderness and should increase the suspicion of bladder and urinary tract injury and prompt the clinician to undertake further investigations. Two patients with high-energy pelvic fractures had bladder ruptures detected intraoperatively despite normal preoperative retrograde cystogram. Both patients had significant clinical indicators suggestive of underlying bladder and urinary tract injury. In both cases, a routine conventional retrograde cystogram was performed but failed to identify the full extent of the bladder injury. A possible reason for misdiagnosis in these cases is the delay between injury and investigation due to tertiary referral of care