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https://www.readbyqxmd.com/read/29346495/long-term-temporal-changes-in-structure-and-function-of-rat-visual-system-after-blast-exposure
#1
Daniel F Shedd, Nikolaus A Benko, Justin Jones, Brian E Zaugg, Robert L Peiffer, Brittany Coats
Purpose: We identify long-term ocular sequelae subsequent to experimental blast exposure. Methods: Male Long-Evans rats were exposed to 230 kPa side-on primary blast overpressure using a compressed air driven shock tube. Visual system function and structure were assessed for 8 weeks after exposure using optokinetic nystagmus and optical coherence tomography. Vitreous protein expression and histology (TUNEL, H&E) were performed at 1 day and 1, 4, and 8 weeks. IOP was recorded bilaterally during blast in a subset of animals...
January 1, 2018: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/29297912/temperature-change-rate-actuated-bubble-mixing-for-homogeneous-rehydration-of-dry-pre-stored-reagents-in-centrifugal-microfluidics
#2
S Hin, N Paust, M Keller, M Rombach, O Strohmeier, R Zengerle, K Mitsakakis
In centrifugal microfluidics, dead volumes in valves downstream of mixing chambers can hardly be avoided. These dead volumes are excluded from mixing processes and hence cause a concentration gradient. Here we present a new bubble mixing concept which avoids such dead volumes. The mixing concept employs heating to create a temperature change rate (TCR) induced overpressure in the air volume downstream of mixing chambers. The main feature is an air vent with a high fluidic resistance, representing a low pass filter with respect to pressure changes...
January 3, 2018: Lab on a Chip
https://www.readbyqxmd.com/read/29289086/statistics-of-peak-overpressure-and-shock-steepness-for-linear-and-nonlinear-n-wave-propagation-in-a-kinematic-turbulence
#3
Petr V Yuldashev, Sébastien Ollivier, Maria M Karzova, Vera A Khokhlova, Philippe Blanc-Benon
Linear and nonlinear propagation of high amplitude acoustic pulses through a turbulent layer in air is investigated using a two-dimensional KZK-type (Khokhlov-Zabolotskaya-Kuznetsov) equation. Initial waves are symmetrical N-waves with shock fronts of finite width. A modified von Kármán spectrum model is used to generate random wind velocity fluctuations associated with the turbulence. Physical parameters in simulations correspond to previous laboratory scale experiments where N-waves with 1.4 cm wavelength propagated through a turbulence layer with the outer scale of about 16 cm...
December 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/29285980/xenon-protects-against-blast-induced-traumatic-brain-injury-in-an-i-in-vitro-i-model
#4
Rita Campos-Pires, Mariia Koziakova, Amina Yonis, Ashni Pau, Warren Macdonald, Katie Harris, Christopher Edge, Nicholas P Franks, Peter Mahoney, Robert Dickinson
The aim of this study was to evaluate the neuroprotective efficacy of the inert gas xenon as a treatment for blast-induced traumatic brain injury in an in vitro laboratory model. We developed a novel blast traumatic brain injury model using C57BL/6N mouse organotypic hippocampal brain-slice cultures exposed to a single shockwave, with the resulting injury quantified using propidium iodide fluorescence. A shock tube blast generator was used to simulate open field explosive blast shockwaves, modeled by the Friedlander waveform...
December 29, 2017: Journal of Neurotrauma
https://www.readbyqxmd.com/read/29241230/influence-of-repetitive-diving-in-saltwater-on-pressure-equalization-and-eustachian-tube-function-in-recreational-scuba-divers
#5
Moritz F Meyer, Manuela Boor, Stefanie Jansen, Eberhard D Pracht, Moritz Felsch, Heinz D Klünter, Karl-Bernd Hüttenbrink, Dirk Beutner, Maria Grosheva
INTRODUCTION: We investigated in a prospective, observational trial the feasibility of using the Eustachian tube function test (ETFT) to measure the effect of repetitive pressure exposure during open seawater dives on Eustachian tube function. METHODS: The study included 28 adult divers during six consecutive days of diving in the Red Sea. Participants underwent otoscopy and ETFT before the first dive, between each dive and after the last dive. ETFT included regular tympanometry (R-tymp), tympanometry after Valsalva (V-tymp) and after swallowing (S-tymp)...
December 2017: Diving and Hyperbaric Medicine: the Journal of the South Pacific Underwater Medicine Society
https://www.readbyqxmd.com/read/29213070/sensitivity-analysis-of-coupled-processes-and-parameters-on-the-performance-of-enhanced-geothermal-systems
#6
S N Pandey, Vikram Vishal
3-D modeling of coupled thermo-hydro-mechanical (THM) processes in enhanced geothermal systems using the control volume finite element code was done. In a first, a comparative analysis on the effects of coupled processes, operational parameters and reservoir parameters on heat extraction was conducted. We found that significant temperature drop and fluid overpressure occurred inside the reservoirs/fracture that affected the transport behavior of the fracture. The spatio-temporal variations of fracture aperture greatly impacted the thermal drawdown and consequently the net energy output...
December 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29119227/-hyaluronic-acid-gels-for-pressure-regulation-in-glaucoma-treatment
#7
REVIEW
M Thaller, H Böhm, C Lingenfelder, F Geiger
BACKGROUND: The increasing numbers of glaucoma patients and complications occuring during treatment, such as restenosis and hypotony, require new treatment options to prevent blindness in patients. Therefore, the abovementioned problems should be solved to prolong the lifetime of implants and to prevent repeated surgery. OBJECTIVE: Can a novel stent with hyaluronic acid hydrogels (HA gel) as a functional unit be used to regulate pressure in glaucoma therapy in the long term? MATERIAL AND METHODS: Model stents were filled with HA gels and it was investigated if these could regulate the pressure and what the underlying mechanism is...
November 8, 2017: Der Ophthalmologe: Zeitschrift der Deutschen Ophthalmologischen Gesellschaft
https://www.readbyqxmd.com/read/29102142/a-method-for-assessing-liner-performance-during-the-peak-milk-flow-period
#8
J F Penry, J Upton, S Leonardi, P D Thompson, D J Reinemann
The objective of this study was to develop a method to quantify the milking conditions under which circulatory impairment of teat tissues occurs during the peak flow period of milking. A secondary objective was to quantify the effect of the same milking conditions on milk flow rate during the peak flow rate period of milking. Additionally, the observed milk flow rate was a necessary input to the calculation of canal area, our quantitative measure of circulatory impairment. A central composite experimental design was used with 5 levels of each of 2 explanatory variables (system vacuum and pulsator ratio), creating 9 treatments including the center point...
October 25, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28994788/evaluating-primary-blast-effects-in-vitro
#9
Niall J Logan, Hari Arora, Claire A Higgins
Exposure to blast events can cause severe trauma to vital organs such as the lungs, ears, and brain. Understanding the mechanisms behind such blast-induced injuries is of great importance considering the recent trend towards the use of explosives in modern warfare and terrorist-related incidents. To fully understand blast-induced injury, we must first be able to replicate such blast events in a controlled environment using a reproducible method. In this technique using shock tube equipment, shock waves at a range of pressures can be propagated over live cells grown in 2D, and markers of cell viability can be immediately analyzed using a redox indicator assay and the fluorescent imaging of live and dead cells...
September 18, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28989030/layer-chromatography-bioassays-directed-screening-and-identification-of-antibacterial-compounds-from-scotch-thistle
#10
Ágnes M Móricz, Dániel Krüzselyi, Ágnes Alberti, András Darcsi, Györgyi Horváth, Péter Csontos, Szabolcs Béni, Péter G Ott
The antibacterial profiling of Onopordum acanthium L. leaf extract and subsequent targeted identification of active compounds is demonstrated. Thin-layer chromatography (TLC) and off-line overpressured layer chromatography (OPLC) coupled with direct bioautography were utilized for investigation of the extract against eight bacterial strains including two plant and three human pathogens and a soil, a marine and a probiotic human gut bacteria. Antibacterial fractions obtaining infusion-transfusion OPLC were transferred to HPLC-MS/MS analysis that resulted in the characterization of three active compounds and two of them were identified as, linoleic and linolenic acid...
November 17, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28984880/low-gas-permeability-of-particulate-films-slows-down-the-aging-of-gas-marbles
#11
Yousra Timounay, Even Ou, Elise Lorenceau, Florence Rouyer
Introducing solid particles into liquid films drastically changes their properties: "gas marbles" can resist overpressure and underpressure ten times larger than their pure liquid counterparts - also known as soap bubbles - before deforming. Such gas marbles can therefore prove to be useful as gas containers able to support stresses. Yet, as their liquid counterparts, they can undergo gas transfer, which can reduce the scope of their applications. However, their permeability has never been characterized. In this paper, we measure the gas permeability of gas marbles through dedicated experiments...
October 6, 2017: Soft Matter
https://www.readbyqxmd.com/read/28973910/universal-poroelastic-mechanism-for-hydraulic-signals-in-biomimetic-and-natural-branches
#12
J-F Louf, G Guéna, E Badel, Y Forterre
Plants constantly undergo external mechanical loads such as wind or touch and respond to these stimuli by acclimating their growth processes. A fascinating feature of this mechanical-induced growth response is that it can occur rapidly and at long distance from the initial site of stimulation, suggesting the existence of a fast signal that propagates across the whole plant. The nature and origin of the signal is still not understood, but it has been recently suggested that it could be purely mechanical and originate from the coupling between the local deformation of the tissues (bending) and the water pressure in the plant vascular system...
October 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28967222/bran-induced-effects-on-the-evolution-of-bubbles-and-rheological-properties-in-bread-dough
#13
S Padma Ishwarya, Kiran M Desai, Srinivasulu Naladala, C Anandharamakrishnan
Evolution of bubbles is the key to volume development in bread dough. The influence of wheat bran on bubble growth in bread dough through the mixing, fermentation, and proofing stages is described as a function of its level of addition. Confocal laser scanning microscopy in combination with image processing tools was used to obtain the bubble size and shape parameters. The relationship between bubble behavior and dough rheology was mapped using biaxial extension and dynamic oscillatory rheometry studies. With increase in level of bran addition, mean bubble size decreased corresponding to each stage and showed an inverse relationship with dough overpressure and elastic modulus...
October 2017: Journal of Texture Studies
https://www.readbyqxmd.com/read/28934237/identification-of-low-overpressure-interval-and-its-implication-to-hydrocarbon-migration-case-study-in-the-yanan-sag-of-the-qiongdongnan-basin-south-china-sea
#14
Qinghai Xu, Wanzhong Shi, Yuhong Xie, Zhenfeng Wang, Xusheng Li, Chuanxin Tong
The Qiongdongnan Basin is a strongly overpressured basin with the maximum pressure coefficient (the ratio of the actual pore pressure versus hydrostatic pressure at the same depth) over 2.27. However, there exists a widespread low-overpressure interval between the strong overpressure intervals in the Yanan Sag of western basin. The mechanisms of the low-overpressure interval are not well understood. Three main approaches, pore pressure test data and well-log analysis, pressure prediction based on the relationship between the deviation of the velocity and the pressure coefficients, and numerical modeling, were employed to illustrate the distribution and evolution of the low-overpressure interval...
2017: PloS One
https://www.readbyqxmd.com/read/28892384/kinetics-of-trifluoromethane-clathrate-hydrate-formation-from-chf3-gas-and-ice-particles
#15
Jaruwan Amtawong, Suvrajit Sengupta, Michael T Nguyen, Nicole C Carrejo, Jin Guo, Everly B Fleischer, Rachel W Martin, Kenneth C Janda
We report the formation kinetics of trifluoromethane clathrate hydrate (CH) from less than 75 μm diameter ice particles and CHF3 gas. As previously observed for difluoromethane and propane hydrate formation, the initial stages of the reaction exhibit a strong negative correlation of the reaction rate with temperature, consistent with a negative activation energy of formation. The values obtained for trifluoromethane, ca. -6 kJ/mol (H2O), are similar to those for difluoromethane, even though the two molecules have different intermolecular interactions and sizes...
September 19, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28876906/water-issues-related-to-transitioning-from-conventional-to-unconventional-oil-production-in-the-permian-basin
#16
Bridget R Scanlon, Robert C Reedy, Frank Male, Mark Walsh
The Permian Basin is being transformed by the "shale revolution" from a major conventional play to the world's largest unconventional play, but water management is critical in this semiarid region. Here we explore evolving issues associated with produced water (PW) management and hydraulic fracturing water demands based on detailed well-by-well analyses. Our results show that although conventional wells produce ∼13 times more water than oil (PW to oil ratio, PWOR = 13), this produced water has been mostly injected back into pressure-depleted oil-producing reservoirs for enhanced oil recovery...
September 6, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28866319/the-effect-of-blast-overpressure-on-the-mechanical-properties-of-a-chinchilla-tympanic-membrane
#17
Junfeng Liang, Zachery A Yokell, Don U Nakmaili, Rong Z Gan, Hongbing Lu
The rupture of tympanic membrane (TM) has long been viewed as an indicator of blast injury, especially for hearing loss. However, little is known about damage to the TM caused by blast with pressure lower than the rupture threshold. In this paper, we present our study on the effect of blast overpressure on the static mechanical properties of TM. Chinchilla was used as the animal model and exposed to multiple blasts with pressures lower than the rupture threshold of the TM. Using a micro-fringe projection method, we observed the alteration of the static mechanical properties of post-blast chinchilla's TMs as compared to those of control TMs...
August 18, 2017: Hearing Research
https://www.readbyqxmd.com/read/28845448/nucleation-speed-limit-on-remote-fluid-induced-earthquakes
#18
Tom Parsons, Luca Malagnini, Aybige Akinci
Earthquakes triggered by other remote seismic events are explained as a response to long-traveling seismic waves that temporarily stress the crust. However, delays of hours or days after seismic waves pass through are reported by several studies, which are difficult to reconcile with the transient stresses imparted by seismic waves. We show that these delays are proportional to magnitude and that nucleation times are best fit to a fluid diffusion process if the governing rupture process involves unlocking a magnitude-dependent critical nucleation zone...
August 2017: Science Advances
https://www.readbyqxmd.com/read/28827423/on-the-effective-stress-law-for-rock-on-rock-frictional-sliding-and-fault-slip-triggered-by-means-of-fluid-injection
#19
Ernest Rutter, Abigail Hackston
Fluid injection into rocks is increasingly used for energy extraction and for fluid wastes disposal, and can trigger/induce small- to medium-scale seismicity. Fluctuations in pore fluid pressure may also be associated with natural seismicity. The energy release in anthropogenically induced seismicity is sensitive to amount and pressure of fluid injected, through the way that seismic moment release is related to slipped area, and is strongly affected by the hydraulic conductance of the faulted rock mass. Bearing in mind the scaling issues that apply, fluid injection-driven fault motion can be studied on laboratory-sized samples...
September 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28810995/chondrocyte-viability-after-a-simulated-blast-exposure
#20
K Aaron Shaw, Peter C Johnson, David Williams, Steven D Zumbrun, Richard Topolski, Craig D Cameron
OBJECTIVES: The effects of blast exposure have gained increasing interest in the military medical community with their continued occurrence on the battlefield. The impact of the direct and indirect energy imparted from blasts to hollow viscera, as well as closed head injuries, have been well studied. However, the injury to articular cartilage has not been investigated, despite previous correlations regarding the development of osteoarthritis. The purpose of this study was to assess the degree of injury to articular chondrocytes after exposure to a simulated blast overpressure wave...
July 2017: Military Medicine
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