430 research outputs found

    Ultrasonic Signals from Worst-Case Hard-Alpha Inclusions Beneath a Random Rough Surface

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    Up to the present time, the detection of hard alpha inclusions in commercial titanium products or in billets has relied on the presence of associated voids and cracks, which due to their sharp edges are good acoustic reflectors at high frequencies. The detection problem becomes much harder, if cracks and voids are absent, since the acoustic impedance of a hard alpha inclusion is at least an order of magnitude smaller. The problem appears to call for the use of high frequency focused probes. However, one cannot use arbitrarily high frequencies for at least three reasons: (1) grain scattering due to the microstructure of titanium, (2) attenuation of the beam due to surface roughness and most importantly (3) the nature of the flaw as discussed below

    Predicting Tenderness in Beef Carcasses by Combining Ultrasound and Mechanical Techniques

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    • Meat tenderness is a concern today in the beef cattle industry, and it will become an even greater concern in the future. • Tenderness is a complex issue, and it is difficult to predict tenderness after cooking by examining raw beef or carcass beef. Unfortunately, tenderness must be evaluated at the carcass level to be a useful tool in the industry. • A star-shaped probe was attached to an InstronÒ machine. This attachment makes it possible to measure tenderness in both raw and cooked Longissimus dorsi steaks. The correlation between raw and cooked was 0.41. • The correlation between cooked star probe values and Warner Bratzler shear values (the standard tenderness measure) was 0.53. • The star-shaped probe applies pressure to beef tissue. This approach was then combined with ultrasound to evaluate firmness or softness of beef tissue. Ultrasound images were collected as increased pressure was applied (elastography). • A probe has been built that attaches to hot carcasses to evaluate this elastography procedure

    Chiari type I malformation with high foramen magnum anomaly

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    A 14-year-old male with a neck pain and hypoesthesia in the upper extremities was diagnosed with Chiari type I malformation (CMI) and syringomyelia. The posterior part of the occipital bone was removed via cranio-cervical decompression. The accuracy of measuring the posterior cranial fossa (PCF) and foramen magnum (FM) dimensions were evaluated and compared with the literature. The linear PCF and FM dimensions as well as volumes were measured using computed tomography (CT) images with different techniques. The volume data were compared with similar data from literature. Use of the posterior fossa approach remains controversial when treating patients with minor little brain stem dislocation, small PCF, and or incomplete C1, but the approach can easily be applied if FM and PCF sizes are known. Linear measurements that were assessed for concordance with CT measurements had the best agreement. Quantification of PCF volume and high FM should be taken into consideration for differential diagnosis of tonsillar herniation and prediction of surgical outcome in CMI

    Magnetic resonance microimaging of the spinal cord in the SOD1 mouse model of amyotrophic lateral sclerosis detects motor nerve root degeneration

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    Amyotrophic lateral sclerosis (ALS) is characterized by selective degeneration of motor neurons. Current imaging studies have concentrated on areas of the brain and spinal cord that contain mixed populations of sensory and motor neurons. In this study, ex vivo magnetic resonance microimaging (MRM) was used to separate motor and sensory components by visualizing individual dorsal and ventral roots in fixed spinal cords. MRM at 15 pm in plane resolution enabled the axons of pure populations of sensory and motor neurons to be measured in the lumbar region of the SOD1 mouse model of ALS. MRM signal intensity increased by 38.3% (p < 0.05) exclusively in the ventral motor nerve roots of the lumbar spinal cord of ALS-affected SOD1 mice compared to wildtype littermates. The hyperintensity was therefore limited to white matter tracts arising from the motor neurons, whereas sensory white matter fibers were unchanged. Significant decreases in ventral nerve root volume were also detected in the SOD1 mice, which correlated with the axonal degeneration observed by microscopy. These results demonstrate the usefulness of MRM in visualizing the ultrastructure of the mouse spinal cord. The detailed 3D anatomy allowed the processes of pure populations of sensory and motor neurons to be compared. (C) 2011 Elsevier Inc. All rights reserved

    Physicians’ and nurses’ decision making to encounter neonates with poor prognosis in the neonatal intensive care unit

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    This is an Accepted Manuscript of an article published by Sage in Clinical Ethics on 03/06/2020. Available online: https://journals.sagepub.com/doi/abs/10.1177/1477750920927173This is an Accepted Manuscript of an article published by Sage in Clinical Ethics on 03/06/2020.Available online: https://journals.sagepub.com/doi/abs/10.1177/1477750920927173acceptedVersio

    Regular and chaotic vibration in a piezoelectric energy harvester

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    We examine regular and chaotic responses of a vibrational energy harvester composed of a vertical beam and a tip mass. The beam is excited horizontally by a harmonic inertial force while mechanical vibrational energy is converted to electrical power through a piezoelectric patch. The mechanical resonator can be described by single or double well potentials depending on the gravity force from the tip mass. By changing the tip mass we examine bifurcations from single well oscillations, to regular and chaotic vibrations between the potential wells. The appearance of chaotic responses in the energy harvesting system is illustrated by the bifurcation diagram, the corresponding Fourier spectra, the phase portraits, and is confirmed by the 0–1 test. The appearance of chaotic vibrations reduces the level of harvested energy

    Effects of temperature dependent viscosity on Bénard convection in a porous medium using a non-Darcy model

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    Temperature-dependent viscosity variation effect on Benard convection, of a gas or a liquid, in an enclosure filled with a porous medium is studied numerically, based on the general model of momentum transfer in a porous medium. The exponential form of viscosity-temperature relation is applied to examine three cases of viscosity-temperature relation: constant (mu = mu(C)), decreasing (down to 0.13 mu C) and increasing (up to 7.39 mu(C)). Effects of fluid viscosity variation on isotherms, streamlines, and the Nusselt number are studied. Application of the effective and average Rayleigh number is examined. Defining a reference temperature, which does not change with the Rayleigh number but increases with the Darcy number, is found to be a viable option to account for temperature-dependent viscosity variation. (C) 2007 Published by Elsevier Ltd

    The IKKâ related kinase TBK1 activates mTORC1 directly in response to growth factors and innate immune agonists

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    The innate immune kinase TBK1 initiates inflammatory responses to combat infectious pathogens by driving production of type I interferons. TBK1 also controls metabolic processes and promotes oncogeneâ induced cell proliferation and survival. Here, we demonstrate that TBK1 activates mTOR complex 1 (mTORC1) directly. In cultured cells, TBK1 associates with and activates mTORC1 through siteâ specific mTOR phosphorylation (on S2159) in response to certain growth factor receptors (i.e., EGFâ receptor but not insulin receptor) and pathogen recognition receptors (PRRs) (i.e., TLR3; TLR4), revealing a stimulusâ selective role for TBK1 in mTORC1 regulation. By studying cultured macrophages and those isolated from genome edited mTOR S2159A knockâ in mice, we show that mTOR S2159 phosphorylation promotes mTORC1 signaling, IRF3 nuclear translocation, and IFNâ β production. These data demonstrate a direct mechanistic link between TBK1 and mTORC1 function as well as physiologic significance of the TBK1â mTORC1 axis in control of innate immune function. These data unveil TBK1 as a direct mTORC1 activator and suggest unanticipated roles for mTORC1 downstream of TBK1 in control of innate immunity, tumorigenesis, and disorders linked to chronic inflammation.SynopsisTBK1, an IKKâ related kinase that drives interferon production as well cancer cell proliferation and survival, phosphorylates mTOR to activate mTORC1 in response to EGF and innate immune agonists, suggesting unanticipated roles for mTORC1 downstream of TBK1 in control of innate immunity and tumorigenesis.TBK1 interacts with mTORC1 and phosphorylates mTOR on S2159 to increase its catalytic activity.Cells lacking TBK1 or expressing a mTOR S2159A allele exhibit reduced mTORC1 signaling in response to EGFâ receptor and TLR3/4 activation.Primary macrophages derived from genome edited mTOR S2159A mice exhibit reduced mTORC1 signaling in response to TLR3/4 activation.Primary macrophages treated with rapamycin as well as those derived from mTORS2159A mice produce reduced levels of IFNâ β due to impaired nuclear translocation of the transcription factor IRF3.Innate immune kinase TBK1â dependent activation of mTORC1 occurs in response to pathogen recognition and EGF receptor activation and drives interferon production, thus highlighting the role of mTOR for innate immunity.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141029/1/embj201696164.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141029/2/embj201696164.reviewer_comments.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141029/3/embj201696164_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141029/4/embj201696164-sup-0001-EVFigs.pd
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