79 research outputs found

    The results of compression forces applied to the isolated human calvaria

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    Data for the force necessary to fracture the isolated calvaria (skull cap) are not available in the extant literature. Twenty dry adult calvaria were tested to failure quasistatically at the vertex using a 15-kN load cell. The forces necessary to fracture or cause diastasis of calvarial sutures were then documented and gross examination of the specimens made. Failure forces had a mean measurement of 2772 N. Initial fractures did not cross suture lines. Prior to complete destruction of the calvaria there were 7 specimens in which all sutures of the calvaria became diastatic, 6 specimens in which the calvaria became diastatic along only the coronal sutures, 2 specimens in which the calvaria became diastatic along only the sagittal suture and 5 specimens in which there were diagonal linear parietal bone fractures. Our hopes are that these data may contribute to the structural design of more safer protective devices for use in our society, assist in predicting injury and aid in the construction of treatment paradigms

    Outcome of experimental stroke in C57Bl/6 and Sv/129 mice assessed by multimodal ultra-high field MRI

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    Transgenic mice bred on C57Bl/6 or Sv/129 genetic background are frequently used in stroke research. It is well established that variations in cerebrovascular anatomy and hemodynamics can influence stroke outcome in different inbred mouse lines. We compared stroke development in C57Bl/6 and Sv/129 mice in the widely used model of transient middle cerebral artery occlusion (tMCAO) by multimodal ultra-high field magnetic resonance imaging (MRI)

    IceCube-Gen2: A Vision for the Future of Neutrino Astronomy in Antarctica

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    20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)The recent observation by the IceCube neutrino observatory of an astrophysical flux of neutrinos represents the "first light" in the nascent field of neutrino astronomy. The observed diffuse neutrino flux seems to suggest a much larger level of hadronic activity in the non-thermal universe than previously thought and suggests a rich discovery potential for a larger neutrino observatory. This document presents a vision for an substantial expansion of the current IceCube detector, IceCube-Gen2, including the aim of instrumenting a 10km310\,\mathrm{km}^3 volume of clear glacial ice at the South Pole to deliver substantial increases in the astrophysical neutrino sample for all flavors. A detector of this size would have a rich physics program with the goal to resolve the sources of these astrophysical neutrinos, discover GZK neutrinos, and be a leading observatory in future multi-messenger astronomy programs

    The IceCube Neutrino Observatory Part III: Cosmic Rays

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    Papers on cosmic rays submitted to the 33nd International Cosmic Ray Conference (Rio de Janeiro 2013) by the IceCube Collaboration

    Rat Model of Global Cerebral Ischemia: The Two-Vessel Occlusion (2VO) Model of Forebrain Ischemia

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    Animal models of brain ischemia can be divided into focal and global brain ischemia. Among global (often referred to as forebrain) ischemia animal models, the 2-vessel occlusion (2VO) and 4-vessel occlusion (4VO) models in rats are most frequently employed in the studies of molecular mechanisms of neuronal damage after brain ischemia followed by reperfusion. This chapter discusses the rat 2VO model. In this model, reversible forebrain ischemia is produced by bilateral common carotid artery (CCA) occlusion combined with systemic hypotension (50 mmHg) sufficient to induce brain ischemia. This ischemia-and-reperfusion model affects widespread areas of the forebrain. There are two chief histopatho-logical changes in this 2VO ischemia model: (1) selective neuronal vulnerability; typically CA1 pyramidal neurons of the hippocampus are most vulnerable, followed by dorsoventral striatal small- and medium-sized neurons, and pyramidal neurons in the layers 3–4 of the neocortex; and (2) delayed neuronal death, i.e., neuronal death does not occur immediately after transient ischemic episode, but takes place after 2–3 days of reperfusion. During the surgical procedure, this model requires artificial maintenance of (1) rectal and brain temperatures at 37°C, (2) the mean arterial blood pressure (MABP), and (3) blood gases. This 2VO ischemia model has the advantage of a one-step surgical procedure that produces high-grade forebrain ischemia. The reproducibility of the ischemic his-topathological damage of this model is more than 90%. This animal model is also suitable for molecular, biochemical, and physiological studies, as well as for evaluation of neuroprotective procedures and agents
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