keyword
MENU ▼
Read by QxMD icon Read
search

Critical velocity

keyword
https://www.readbyqxmd.com/read/29229306/pseudo-continuous-arterial-spin-labeling-quantification-in-anemic-subjects-with-hyperemic-cerebral-blood-flow
#1
Adam Bush, Yaqiong Chai, So Young Choi, Lena Vaclavu, Scott Holland, Aart Nederveen, Thomas Coates, John Wood
PURPOSE: To investigate possible sources of quantification errors in global cerebral blood flow (CBF) measurements by comparing pseudo continuous arterial spin labeling (PCASL) and phase contrast (PC) MRI in anemic, hyperemic subjects. METHODS: All studies were performed on a Philips 3T Achieva MRI scanner. PC and PCASL CBF examinations were performed in 10 healthy, young adult subjects and 18 young adults with chronic anemia syndromes including sickle cell disease and thalassemia...
December 8, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29223876/joint-moments-required-to-hold-a-posture-while-somersaulting
#2
Joanne Mikl
A pure somersault is a key skill in diving and gymnastics, and involves rotation about the transverse axis of the body. As the rotational speed increases the effort required to maintain a specified posture increases. This paper derives equations for the joint moments required for an athlete to hold three sport specific postures as a function of rotational speed. The joint moment is related to the isometric muscular strength and is the limiting factor of an athlete in their ability to hold a fixed posture while somersaulting...
December 7, 2017: Human Movement Science
https://www.readbyqxmd.com/read/29222545/coefficient-of-friction-between-carboxymethylated-hyaluronic-acid-based-polymer-films-and-the-ocular-surface
#3
Jourdan Colter, Barbara Wirostko, Brittany Coats
Purpose: Hyaluronic acid-based polymer films are emerging as drug-delivery vehicles for local and continuous drug administration to the eye. The highly lubricating hyaluronic acid increases comfort, but displaces films from the eye, reducing drug exposure and efficacy. Previous studies have shown that careful control of the surface interaction of the film with the eye is critical for improved retention. Methods: In this study, the frictional interaction of a carboxymethylated, hyaluronic acid-based polymer (CMHA-S) with and without methylcellulose was quantified against ovine and human sclera at three axial loads (0...
December 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/29221029/effect-of-crystalline-family-and-orientation-on-stimulated-brillouin-scattering-in-whispering-gallery-mode-resonators
#4
Souleymane Diallo, Jean-Pierre Aubry, Yanne K Chembo
Ultra-high Q whispering-gallery mode resonators pumped by a continuous-wave laser are known to enhance stimulated Brillouin scattering when optimal resonance and phase-matching conditions are met. In crystalline resonators, this process depends critically on the crystal orientation and family, which impose the elastic constants defining the velocity of the acoustic waves. In this article, we investigate the effect of crystalline orientation and family on this velocity which is proportional to the Brillouin frequency down-shift...
November 27, 2017: Optics Express
https://www.readbyqxmd.com/read/29219343/revision-of-bubble-bursting-universal-scaling-laws-of-top-jet-drop-size-and-speed
#5
Alfonso M Gañán-Calvo
The collapse of a bubble of radius R_{o} at the surface of a liquid generating a liquid jet and a subsequent first drop of radius R is universally scaled using the Ohnesorge number Oh=μ/(ρσR_{o})^{1/2} and a critical value Oh^{*} below which no droplet is ejected; ρ, σ, and μ are the liquid density, surface tension, and viscosity, respectively. First, a flow field analysis at ejection yields the scaling of R with the jet velocity V as R/l_{μ}∼(V/V_{μ})^{-5/3}, where l_{μ}=μ^{2}/(ρσ) and V_{μ}=σ/μ...
November 17, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29217091/microstructural-changes-associated-with-osteoporosis-negatively-affect-loading-induced-fluid-flow-around-osteocytes-in-cortical-bone
#6
Vittorio Gatti, Evan M Azoulay, Susannah P Fritton
Loading-induced interstitial fluid flow in the microporosities of bone is critical for osteocyte mechanotransduction and for the maintenance of tissue health, enhancing convective transport in the lacunar-canalicular system. In recent studies, our group has reported alterations of bone's vascular porosity and lacunar-canalicular system microarchitecture in a rat model of postmenopausal osteoporosis. In this work, poroelastic finite element analysis was used to investigate whether these microstructural changes can affect interstitial fluid flow around osteocytes...
November 16, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29208757/critical-velocity-determined-by-a-non-exhaustive-method-in-subjects-with-copd
#7
Marceli Rocha Leite, Juliana Souza Uzeloto, Bruna Spolador de Alencar Silva, Ana Paula Coelho Figueira Freire, Fabiano Francisco de Lima, Eduardo Zapaterra Campos, Diego Giulliano Destro Christofaro, Carlos Augusto Kalva-Filho, Dionei Ramos, Ercy Mara Cipulo Ramos
BACKGROUND: Exercise training is an effective and low-cost tool for COPD rehabilitation. Thus, validating a non-exhaustive method to determine a patient's anaerobic threshold would be a very interesting tool in practical settings. We aimed to test the reproducibility of critical velocity values determined in a non-exhaustive manner (CVNE) and tolerance for exercise performed at this physiological marker in subjects with COPD. METHODS: Twelve subjects with COPD were evaluated in this cross-sectional study...
December 5, 2017: Respiratory Care
https://www.readbyqxmd.com/read/29202338/cranial-trauma-in-handgun-executions-experimental-data-using-polyurethane-proxies
#8
Seth C Taylor, Elena F Kranioti
Gun violence is a global phenomenon with regional variation in frequency and severity. Handguns are often used in violent deaths such as suicides and homicides. Hence, ballistic trauma is a critical subject of forensic investigations. Trauma patterns are fundamental evidence for the reconstruction of the incident and for the determination of the manner of death. This study investigated the differences in trauma patterns with a series of experiments using six different calibers (.22 LR, .38 Special, .380 ACP, 9×19mm, ...
November 27, 2017: Forensic Science International
https://www.readbyqxmd.com/read/29198058/analyzing-gait-variability-and-dual-task-interference-in-patients-with-parkinson-s-disease-and-freezing-by-means-of-the-word-color-stroop-test
#9
Ana Francisca Rozin Kleiner, Aline S Pagnussat, Giulia di Prisco, Alessandro Vagnini, Fabrizio Stocchi, Maria Francesca De Pandis, Manuela Galli
The ability to carry out two tasks at once is critical to effective functioning in the real world and deficits are termed Dual-task interference or effect-DTE. DTE substantially compromised the gait of subjects with Parkinson's disease and freezing of gait (PD + FOG), leading to exaggerated slowing, increasing gait dysrhythmicity, and inducing FOG episodes. This study aimed to investigate the DTE in gait variability of subjects with PD and freezing of gait (PD + FOG). Thirty-three patients with PD + FOG and 14 healthy individuals (REFERENCE) took part at this study...
December 2, 2017: Aging Clinical and Experimental Research
https://www.readbyqxmd.com/read/29195471/analysis-of-the-transient-surface-wave-propagation-in-soft-solid-elastic-plates
#10
Nicolás Benech, Javier Brum, Gustavo Grinspan, Sofía Aguiar, Carlos A Negreira
In dynamic elastography, the goal is to estimate the Young's modulus from audio-frequency wave propagation in soft-tissues. Within this frequency range, the shear wavelength is centimeter-sized while the compressional wavelength is meter-sized. Thus, the experimental data are usually collected in the near-field of the source. Near-field effects have been widely studied for bulk wave propagation. However, the near- and transient-fields of surface and guided waves have received less attention. In this work, the transient surface displacement field in soft-solid elastic plates in vacuum is analyzed...
November 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/29195302/transient-behavior-between-multi-cell-flow-states-in-ferrofluidic-taylor-couette-flow
#11
Sebastian Altmeyer, Younghae Do, Soorok Ryu
We investigate transient behaviors induced by magnetic fields on the dynamics of the flow of a ferrofluid in the gap between two concentric, independently rotating cylinders. Without applying any magnetic fields, we uncover emergence of flow states constituted by a combination of a localized spiral state in the top and bottom of the annulus and different multi-cell flow states with toroidally closed vortices in the interior of the bulk. However, when a magnetic field is presented, we observe the transient behaviors between multi-cell states passing through two critical thresholds in a strength of an axial (transverse) magnetic field...
November 2017: Chaos
https://www.readbyqxmd.com/read/29186851/gnss-electronic-compass-road-segment-information-fusion-for-vehicle-to-vehicle-collision-avoidance-application
#12
Rui Sun, Qi Cheng, Dabin Xue, Guanyu Wang, Washington Yotto Ochieng
The increasing number of vehicles in modern cities brings the problem of increasing crashes. One of the applications or services of Intelligent Transportation Systems (ITS) conceived to improve safety and reduce congestion is collision avoidance. This safety critical application requires sub-meter level vehicle state estimation accuracy with very high integrity, continuity and availability, to detect an impending collision and issue a warning or intervene in the case that the warning is not heeded. Because of the challenging city environment, to date there is no approved method capable of delivering this high level of performance in vehicle state estimation...
November 25, 2017: Sensors
https://www.readbyqxmd.com/read/29176384/the-use-of-mobile-applications-to-collect-data-in-sport-health-and-exercise-science-a-narrative-review
#13
Daniel J Peart, Carlos Balsalobre-Fernández, Matthew P Shaw
Mobile devices are ubiquitous in the population, and most have the capacity to download applications (apps). Some apps have been developed to collect physiological, kinanthropometric and performance data, however the validity and reliability of such data is often unknown. An appraisal of such apps is warranted as mobile apps may offer an alternative method of data collection for practitioners and athletes with money, time and space constraints. This article identifies and critically reviews the commercially available apps that have been tested in the scientific literature, finding evidence to support the measurement of resting heart through photoplethysmograpy, heart rate variability, range of motion, barbell velocity, vertical jump, mechanical variables during running, and distances covered during walking, jogging and running...
November 22, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/29170456/determination-of-asphaltene-critical-nanoaggregate-concentration-region-using-ultrasound-velocity-measurements
#14
Aleksandra Svalova, Nicholas G Parker, Malcolm J W Povey, Geoffrey D Abbott
Asphaltenes constitute the heaviest, most polar and aromatic fraction of petroleum crucial to the formation of highly-stable water-in-crude oil emulsions. The latter occur during crude oil production as well as spills and cause difficulties to efficient remediation practice. It is thought that in nanoaggregate form, asphaltenes create elastic layers around water droplets enhancing stability of the emulsion matrix. Ultrasonic characterisation is a high-resolution non-invasive tool in colloidal analysis shown to successfully identify asphaltene nanoaggregation in toluene...
November 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29168517/crossed-beam-polyatomic-reaction-dynamics-recent-advances-and-new-insights
#15
REVIEW
Huilin Pan, Kopin Liu, Adriana Caracciolo, Piergiorgio Casavecchia
Over the past ten years or so, great advances in our understanding of the dynamics of elementary (bimolecular) polyatomic reactions in the gas-phase have occurred. This has been made possible by critical improvements (a) in crossed molecular beam (CMB) instruments with rotating mass spectrometric detection and time-of-flight analysis, especially following the implementation of soft ionization (by tunable low energy electrons or vacuum-ultraviolet synchrotron radiation) for product detection with increased sensitivity and universal detection power, and (b) in REMPI-slice velocity map ion imaging (VMI) detection techniques in pulsed CMB experiments for obtaining product pair-correlated information through high-resolution measurements directly in the center of mass system...
November 23, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/29164023/type-and-timing-of-rehabilitation-following-acute-and-subacute-spinal-cord-injury-a-systematic-review
#16
REVIEW
Anthony S Burns, Ralph J Marino, Sukhvinder Kalsi-Ryan, James W Middleton, Lindsay A Tetreault, Joseph R Dettori, Kathryn E Mihalovich, Michael G Fehlings
Objectives: The objective of this study was to conduct a systematic review of the literature to address the following clinical questions: In adult patients with acute and subacute complete or incomplete traumatic SCI, (1) does the time interval between injury and commencing rehabilitation affect outcome?; (2) what is the comparative effectiveness of different rehabilitation strategies, including different intensities and durations of treatment?; (3) are there patient or injury characteristics that affect the efficacy of rehabilitation?; and (4) what is the cost-effectiveness of various rehabilitation strategies? Methods: A systematic search was conducted for literature published through March 31, 2015 that evaluated rehabilitation strategies in adults with acute or subacute traumatic SCI at any level...
September 2017: Global Spine Journal
https://www.readbyqxmd.com/read/29162233/mechanical-characterisation-of-agarose-based-chromatography-resins-for-biopharmaceutical-manufacture
#17
Mauryn C Nweke, R Graham McCartney, Daniel G Bracewell
Mechanical characterisation of agarose-based resins is an important factor in ensuring robust chromatographic performance in the manufacture of biopharmaceuticals. Pressure-flow profiles are most commonly used to characterise these properties. There are a number of drawbacks with this method, including the potential need for several re-packs to achieve the desired packing quality, the impact of wall effects on experimental set up and the quantities of chromatography media and buffers required. To address these issues, we have developed a dynamic mechanical analysis (DMA) technique that characterises the mechanical properties of resins based on the viscoelasticity of a 1ml sample of slurry...
November 18, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29161318/loss-of-mtorc2-signaling-in-oligodendrocyte-precursor-cells-delays-myelination
#18
Mark D Grier, Kathryn L West, Nathaniel D Kelm, Cary Fu, Mark D Does, Brittany Parker, Eleanor McBrier, Andre H Lagrange, Kevin C Ess, Robert P Carson
Myelin abnormalities are increasingly being recognized as an important component of a number of neurologic developmental disorders. The integration of many signaling pathways and cell types are critical for correct myelinogenesis. The PI3-K and mechanistic target of rapamycin (mTOR) pathways have been found to play key roles. mTOR is found within two distinct complexes, mTORC1 and mTORC2. mTORC1 activity has been shown to play a major role during myelination, while the role of mTORC2 is not yet well understood...
2017: PloS One
https://www.readbyqxmd.com/read/29158392/high-postural-costs-and-anaerobic-metabolism-during-swimming-support-the-hypothesis-of-a-u-shaped-metabolism-speed-curve-in-fishes
#19
Valentina Di Santo, Christopher P Kenaley, George V Lauder
Swimming performance is considered a key trait determining the ability of fish to survive. Hydrodynamic theory predicts that the energetic costs required for fishes to swim should vary with speed according to a U-shaped curve, with an expected energetic minimum at intermediate cruising speeds and increasing expenditure at low and high speeds. However, to date no complete datasets have shown an energetic minimum for swimming fish at intermediate speeds rather than low speeds. To address this knowledge gap, we used a negatively buoyant fish, the clearnose skate Raja eglanteria, and took two approaches: a classic critical swimming speed protocol and a single-speed exercise and recovery procedure...
November 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29156723/effects-of-pharmacological-gap-junction-and-sodium-channel-blockade-on-s1s2-restitution-properties-in-langendorff-perfused-mouse-hearts
#20
Gary Tse, Tong Liu, Guangping Li, Wendy Keung, Jie Ming Yeo, Yin Wah Fiona Chan, Bryan P Yan, Yat Sun Chan, Sunny Hei Wong, Ronald A Li, Jichao Zhao, William K K Wu, Wing Tak Wong
Gap junctions and sodium channels are the major molecular determinants of normal and abnormal electrical conduction through the myocardium, however, their exact contributions to arrhythmogenesis are unclear. We examined conduction and recovery properties of regular (S1) and extrasystolic (S2) action potentials (APs), S1S2 restitution and ventricular arrhythmogenicity using the gap junction and sodium channel inhibitor heptanol (2 mM) in Langendorff-perfused mouse hearts (n=10). Monophasic action potential recordings obtained during S1S2 pacing showed that heptanol increased the proportion of hearts showing inducible ventricular tachycardia (0/10 vs...
October 17, 2017: Oncotarget
keyword
keyword
19527
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"