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https://www.readbyqxmd.com/read/28634733/dynamic-properties-of-human-tympanic-membrane-after-exposure-to-blast-waves
#1
Warren G Engles, Xuelin Wang, Rong Z Gan
Blast overpressure causes dynamic damage to middle ear components, and tympanic membrane (TM) rupture is the most frequent middle ear injury. However, it is unclear how the blast waves change mechanical properties of the TM and affect sound transmission through the ear. This paper reports the current study on dynamic properties of the TM after exposure to blast waves by using acoustic loading and laser Doppler vibrometry (LDV). The TM specimens were prepared from human temporal bones following exposures to blast overpressure...
June 20, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28634463/protective-effect-of-n-acetylcysteine-amide-on-blast-induced-increase-in-intracranial-pressure-in-rats
#2
Usmah Kawoos, Richard M McCarron, Mikulas Chavko
Blast-induced traumatic brain injury is associated with acute and possibly chronic elevation of intracranial pressure (ICP). The outcome after TBI is dependent on the progression of complex processes which are mediated by oxidative stress. So far, no effective pharmacological protection against TBI exists. In this study, rats were exposed to a single or repetitive blast overpressure (BOP) at moderate intensities of 72 or 110 kPa in a compressed air-driven shock tube. The degree and duration of the increase in ICP were proportional to the intensity and frequency of the blast exposure(s)...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28630536/effects-of-filament-size-on-critical-current-density-in-overpressure-processed-bi-2212-round-wire
#3
Jianyi Jiang, Ashleigh Francis, Ryan Alicea, Maxime Matras, Fumitake Kametani, Ulf P Trociewitz, Eric E Hellstrom, David C Larbalestier
Bi2Sr2CaCu2Ox (Bi-2212) conductor is the only high temperature superconductor manufactured as a round wire and is a very promising conductor for very high field applications. One of the key design parameters of Bi-2212 wire is its filament size, which has been previously reported to affect the critical current density (Jc ) and ac losses. Work with 1 bar heat treatment showed that the optimal filament diameter was about 15 μm but it was not well understood at that time that gas bubbles were the main current limiting mechanism...
June 2017: IEEE Transactions on Applied Superconductivity: a Publication of the IEEE Superconductivity Committee
https://www.readbyqxmd.com/read/28618553/mechanism-of-unconfined-dust-explosions-turbulent-clustering-and-radiation-induced-ignition
#4
Michael Liberman, Nathan Kleeorin, Igor Rogachevskii, Nils Erland L Haugen
It is known that unconfined dust explosions typically start off with a relatively weak primary flame followed by a severe secondary explosion. We show that clustering of dust particles in a temperature stratified turbulent flow ahead of the primary flame may give rise to a significant increase in the radiation penetration length. These particle clusters, even far ahead of the flame, are sufficiently exposed and heated by the radiation from the flame to become ignition kernels capable to ignite a large volume of fuel-air mixtures...
May 2017: Physical Review. E
https://www.readbyqxmd.com/read/28599600/transcriptional-changes-in-the-mouse-retina-following-ocular-blast-injury-a-role-for-the-immune-system
#5
Felix L Struebing, Rebecca King, Ying Li, Micah A Chrenek, Polina N Lyuboslavsky, Curran S Sidhu, P Michael Iuvone, Eldon E Geisert
Ocular blast injury is a major medical concern for soldiers and explosion victims due to poor visual outcomes. To define the changes in gene expression following a blast injury to the eye, we examined retinal RNA expression in 54 mouse strains five days after a single 50psi overpressure air wave blast injury. We observe that almost 40% of genes are differentially expressed with a false discovery rate of <0.001, even though the nominal changes in RNA expression are rather small. Moreover, we find through machine learning approaches that genetic networks related to the innate and acquired immune system are activated...
June 9, 2017: Journal of Neurotrauma
https://www.readbyqxmd.com/read/28580981/seeding-layer-assisted-selective-area-growth-of-as-rich-inasp-nanowires-on-inp-substrates
#6
Dingkun Ren, Alan C Farrell, Benjamin S Williams, Diana L Huffaker
We present the first demonstration of arsenic-rich InAs1-xPx (0 ≤ x ≤ 0.33) nanowire arrays grown on InP (111)B substrates by catalyst-free selective-area metal-organic chemical vapor deposition. It is shown that by introducing a thin InAs seeding layer prior to the growth of the nanowire, an extremely high vertical yield is achieved by eliminating rotational twins between (111)A and (111)B crystal orientations. InAsP nanowire arrays show strong emission of photoluminescence (PL) at room temperature, suggesting a significant reduction of surface state density compared with InAs nanowires...
June 5, 2017: Nanoscale
https://www.readbyqxmd.com/read/28553646/protection-against-blast-induced-traumatic-brain-injury-by-increase-in-brain-volume
#7
Ming Gu, Usmah Kawoos, Richard McCarron, Mikulas Chavko
Blast-induced traumatic brain injury (bTBI) is a leading cause of injuries in recent military conflicts and it is responsible for an increased number of civilian casualties by terrorist attacks. bTBI includes a variety of neuropathological changes depending on the intensity of blast overpressure (BOP) such as brain edema, neuronal degeneration, diffuse axonal damage, and vascular dysfunction with neurological manifestations of psychological and cognitive abnormalities. Internal jugular vein (IJV) compression is known to reduce intracranial compliance by causing an increase in brain volume and was shown to reduce brain damage during closed impact-induced TBI...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28542917/characterizing-the-performance-of-pipe-bombs
#8
Jimmie C Oxley, James L Smith, Evan T Bernier, Fredrick Sandstrom, Gregory G Weiss, Gunther W Recht, David Schatzer
Pipe bombs of steel or PVC fragment in reproducible patterns when similarly configured. The power of the explosion correlates with number, mass, and size of the fragments recovered, where a large number of small, low-mass fragments indicate a high-power event and vice versa. In discussing performance, describing pipe fragmentation pattern by fragment weight distribution mapping (FWDM) or fragment surface area distribution mapping (FSADM) was useful. When fillers detonated, detonation velocities of ~4.4 mm/μs were measured...
May 24, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28526787/development-of-multi-well-plate-methods-using-pure-cultures-of-methanogens-to-identify-new-inhibitors-for-suppressing-ruminant-methane-emissions
#9
M R Weimar, J Cheung, D Dey, C McSweeney, M Morrison, Y Kobayashi, W B Whitman, V Carbone, L R Schofield, R S Ronimus, G M Cook
Hydrogenotrophic methanogens typically require strictly anaerobic culturing conditions in glass tubes with overpressures of H2 and CO2 that are both time-consuming and costly. To increase the throughput for screening chemical compound libraries, 96-well microtiter plate methods for the growth of a marine (environmental) methanogen Methanococcus maripaludis strain S2 and the rumen methanogen Methanobrevibacter species AbM4 were developed. A number of key parameters (inoculum size, reducing agents for media preparation, duration of assay, inhibitor solvents and culture volume) were optimised to achieve robust and reproducible growth in a high-throughput microtiter plate format...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28508893/south-american-plate-advance-and-forced-andean-trench-retreat-as-drivers-for-transient-flat-subduction-episodes
#10
Gerben Schepers, Douwe J J van Hinsbergen, Wim Spakman, Martha E Kosters, Lydian M Boschman, Nadine McQuarrie
At two trench segments below the Andes, the Nazca Plate is subducting sub-horizontally over ∼200-300 km, thought to result from a combination of buoyant oceanic-plateau subduction and hydrodynamic mantle-wedge suction. Whether the actual conditions for both processes to work in concert existed is uncertain. Here we infer from a tectonic reconstruction of the Andes constructed in a mantle reference frame that the Nazca slab has retreated at ∼2 cm per year since ∼50 Ma. In the flat slab portions, no rollback has occurred since their formation at ∼12 Ma, generating 'horse-shoe' slab geometries...
May 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28504823/centrifugal-driven-reduced-dimension-planar-chromatography
#11
Rachel B Strickhouser, Nahla A Hatab, Nickolay V Lavrik, Michael J Sepaniak
A fundamental problem with efficiency in capillary action driven planar chromatography results from diminishing flow rates as development proceeds, giving rise to molecular diffusion related band dispersion for most sample types. Overpressure and electrokinetic means to speed flow have been used successfully in TLC. We explore the use of centrifugal force (CF) to drive flow for reduced-dimension planar platforms (ultra-TLC, low μm features, and nano-TLC, nanoscale features). The silicon wafer platforms have two forms of continuous 2-D arrays created by either photolithography or metal dewetting followed by deep reactive ion etching and coated with porous SiO2 ...
May 15, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28504263/dehydration-driven-stress-transfer-triggers-intermediate-depth-earthquakes
#12
Thomas P Ferrand, Nadège Hilairet, Sarah Incel, Damien Deldicque, Loïc Labrousse, Julien Gasc, Joerg Renner, Yanbin Wang, Harry W Green Ii, Alexandre Schubnel
Intermediate-depth earthquakes (30-300 km) have been extensively documented within subducting oceanic slabs, but their mechanics remains enigmatic. Here we decipher the mechanism of these earthquakes by performing deformation experiments on dehydrating serpentinized peridotites (synthetic antigorite-olivine aggregates, minerals representative of subduction zones lithologies) at upper mantle conditions. At a pressure of 1.1 gigapascals, dehydration of deforming samples containing only 5 vol% of antigorite suffices to trigger acoustic emissions, a laboratory-scale analogue of earthquakes...
May 15, 2017: Nature Communications
https://www.readbyqxmd.com/read/28479675/understanding-the-densification-process-of-bi2sr2cacu2ox-round-wires-with-overpressure-processing-and-its-effect-on-critical-current-density
#13
M R Matras, J Jiang, D C Larbalestier, E E Hellstrom
Overpressure (OP) processing increases the critical current density (JC ) of Bi2Sr2CaCu2Ox (2212) round wires by shrinking the surrounding Ag matrix around the 2212 filaments, driving them close to full density and greatly increasing the 2212 grain connectivity. Indeed densification is vital for attaining the highest JC . Here, we investigate the time and temperature dependence of the wire densification. We find that the wire diameter decreases by 3.8 ± 0.3 % after full heat treatment at 50 atm and 100 atm OP...
October 2016: Superconductor Science & Technology
https://www.readbyqxmd.com/read/28438658/antioxidants-reduce-neurodegeneration-and-accumulation-of-pathologic-tau-proteins-in-the-auditory-system-after-blast-exposure
#14
Xiaoping Du, Matthew B West, Qunfeng Cai, Weihua Cheng, Donald L Ewert, Wei Li, Robert A Floyd, Richard D Kopke
Cochlear neurodegeneration commonly accompanies hair cell loss resulting from aging, ototoxicity, or exposures to intense noise or blast overpressures. However, the precise pathophysiological mechanisms that drive this degenerative response have not been fully elucidated. Our laboratory previously demonstrated that non-transgenic rats exposed to blast overpressures exhibited marked somatic accumulation of neurotoxic variants of the microtubule-associated protein, Tau, in the hippocampus. In the present study, we extended these analyses to examine neurodegeneration and pathologic Tau accumulation in the auditory system in response to blast exposure and evaluated the potential therapeutic efficacy of antioxidants on short-circuiting this pathological process...
April 22, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28419850/overpressure-blast-injury-induced-oxidative-stress-and-neuroinflammation-response-in-rat-frontal-cortex-and-cerebellum
#15
Hale Z Toklu, Zhihui Yang, Sehkar Oktay, Yasemin Sakarya, Nataliya Kirichenko, Michael K Matheny, Judy Muller-Delp, Kevin Strang, Philip J Scarpace, Kevin K W Wang, Nihal Tümer
BACKGROUND & AIM: Overpressure blast-wave induced brain injury (OBI) and its long-term neurological outcome pose significant concerns for military personnel. Our aim is to investigate the mechanism of injury due to OBI. METHODS: Rats were divided into 3 groups: (1) Control, (2) OBI (exposed 30psi peak pressure, 2-2.5ms), (3) Repeated OBI (r-OBI) (three exposures over one-week period). Lung and brain (cortex and cerebellum) tissues were collected at 24h post injury...
April 15, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28403239/simulated-blast-overpressure-induces-specific-astrocyte-injury-in-an-ex-vivo-brain-slice-model
#16
Saranya Canchi, Malisa Sarntinoranont, Yu Hong, Jeremy J Flint, Ghatu Subhash, Michael A King
Exposure to explosive blasts can produce functional debilitation in the absence of brain pathology detectable at the scale of current diagnostic imaging. Transient (ms) overpressure components of the primary blast wave are considered to be potentially damaging to the brain. Astrocytes participate in neuronal metabolic maintenance, blood-brain barrier, regulation of homeostatic environment, and tissue remodeling. Damage to astrocytes via direct physical forces has the potential to disrupt local and global functioning of neuronal tissue...
2017: PloS One
https://www.readbyqxmd.com/read/28402895/explosion-hazards-of-lpg-air-mixtures-in-vented-enclosure-with-obstacles
#17
Qi Zhang, Yaxing Wang, Zhen Lian
Numerical simulations were performed to study explosion characteristics of liquefied petroleum gas (LPG) explosion in enclosure with a vent. Unlike explosion overpressure and dynamic pressure, explosion temperature of the LPG-air mixture at a given concentration in a vented enclosure has very little variation with obstacle numbers for a given blockage ratio. For an enclosure without obstacle, explosion overpressures for the stoichiometric mixtures and the fuel-lean mixtures reach their maximum within the vent and that for fuel-rich mixture reaches its maximum beyond and near the vent...
April 1, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28329435/face-shield-design-against-blast-induced-head-injuries
#18
Long Bin Tan, Kwong Ming Tse, Yuan Hong Tan, Mohamad Ali Bin Sapingi, Vincent Beng Chye Tan, Heow Pueh Lee
Blast-induced traumatic brain injury (TBI) has been on the rise in recent years due to the increasing use of improvised explosive devices (IEDs) in conflict zones. Our study investigates the response of a helmeted human head subjected to a blast of 1 atm peak overpressure, for cases with and without a standard polycarbonate (PC) face shield and for face shields comprising of composite PC and aerogel materials and with lateral edge extension. The novel introduction of aerogel into the laminate face shield is explored and its wave-structure interaction mechanics and performance in blast mitigation is analysed...
March 22, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/28290006/exercise-testing-and-stress-imaging-in-mitral-valve-disease
#19
REVIEW
Damien Voilliot, Patrizio Lancellotti
Mitral valve disease represented by mitral stenosis and mitral regurgitation is the second most frequent valvulopathy. Mitral stenosis leads to an increased left atrial pressure whereas mitral regurgitation leads to an increased left atrial pressure associated with a volume overload. Secondary to an upstream transmission of this overpressure, both mitral stenosis and regurgitation lead to pulmonary hypertension and right heart failure. In addition, mitral regurgitation also leads to left ventricular dilatation and dysfunction with left heart failure...
March 2017: Current Treatment Options in Cardiovascular Medicine
https://www.readbyqxmd.com/read/28289914/firecracker-eye-exposure-experimental-study-and-simulation
#20
Chiara Clemente, Luca Esposito, Domenico Speranza, Nicola Bonora
Understanding the mechanisms of traumatic ocular injury is helpful to make accurate diagnoses before the symptoms emerge and to develop specific eye protection. The comprehension of the dynamics of primary blast injury mechanisms is a challenging issue. The question is whether the pressure wave propagation and reflection alone could cause ocular damage. To date, there are dissenting opinions and no conclusive evidence thereupon. A previous numerical investigation of blast trauma highlighted the dynamic effect of pressure propagation and its amplification by the geometry of the bony orbit, inducing a resonance cavity effect and a standing wave hazardous for eye tissues...
March 13, 2017: Biomechanics and Modeling in Mechanobiology
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