keyword
MENU ▼
Read by QxMD icon Read
search

Shear stress

keyword
https://www.readbyqxmd.com/read/27933032/bifurcation-type-and-larger-low-shear-area-are-associated-with-rupture-status-of-very-small-intracranial-aneurysms
#1
Yisen Zhang, Zhongbin Tian, Linkai Jing, Ying Zhang, Jian Liu, Xinjian Yang
BACKGROUND: Characterization of the risk factors for rupture of very small intracranial aneurysm (VSIA, ≤3 mm) is clinically valuable, since VSIAs are implicated in subarachnoid hemorrhage. The aim of this study was to identify morphological and hemodynamic parameters that independently characterize the rupture status of VSIAs. METHODS: We conducted a retrospective study of consecutive VSIAs between September 2010 and February 2014 in our institute. A series of morphologic and hemodynamic parameters were evaluated using computational fluid dynamics, based on patient-specific three-dimensional geometrical models...
2016: Frontiers in Neurology
https://www.readbyqxmd.com/read/27932205/cold-induced-sympathetic-tone-modifies-the-impact-of-endothelium-dependent-vasodilation-in-the-finger-pulp
#2
Tone Kristin Bergersen, Maria Skytioti, Maja Elstad
OBJECTIVE: In thermoneutral and cold subjects, the sympathetic nervous system regulates skin blood flow by adjusting frequency of the tonic vasoconstrictor impulses. However, the way these thermoregulatory impulses influence the vascular endothelium is not well known. We studied how the sympathetic nervous system influences endothelium-dependent vasodilation (EDV) caused by shear stress in skin containing arteriovenous anastomoses (AVAs) and arterioles in healthy subjects. METHODS: Thirteen healthy subjects were exposed to thermoneutral (29°C) and cold (22°C) ambient temperatures on separate days...
November 30, 2016: Autonomic Neuroscience: Basic & Clinical
https://www.readbyqxmd.com/read/27930810/alamandine-abrogates-neutrophil-degranulation-in-atherosclerotic-mice
#3
Analina R Da Silva, Sébastien Lenglet, Federico Carbone, Fabienne Burger, Aline Roth, Luca Liberale, Aldo Bonaventura, Franco Dallegri, Nikolaos Stergiopulos, Robson A S Santos, François Mach, Rodrigo A Fraga-Silva, Fabrizio Montecucco
Neutrophil-mediated inflammation was recently identified as an active contributor to athero-progression. Therapeutic strategies inhibiting neutrophil degranulation or recruitment were hypothesized to positively impact on plaque vulnerability. In this study, we investigated whether treatment with the recently discovered agonist of the Mas-related G-coupled receptor type D (MrgD) alamandine would impact on neutrophil degranulation in vivo and in vitro MATERIALS AND METHODS: Fifteen-week old ApoE-/- mice were fed with a Western-type diet for an additional 11 weeks...
December 8, 2016: European Journal of Clinical Investigation
https://www.readbyqxmd.com/read/27929142/an-experimental-investigation-of-the-risk-of-triggering-geological-disasters-by-injection-under-shear-stress
#4
Yixin Liu, Jiang Xu, Shoujian Peng
Fluid injection has been applied in many fields, such as hazardous waste deep well injection, forced circulation in geothermal fields, hydraulic fracturing, and CO2 geological storage. However, current research mainly focuses on geological data statistics and the dominating effects of pore pressure. There are only a few laboratory-conditioned studies on the role of drilling boreholes and the effect of injection pressure on the borehole wall. Through experimental phenomenology, this study examines the risk of triggering geological disasters by fluid injection under shear stress...
December 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27928997/large-electrorheological-phenomena-in-graphene-nano-gels
#5
Purbarun Dhar, Ajay Katiyar, Arvind Pattamatta, Sarit K Das
Large-scale electrorheology (ER) response has been reported for dilute graphene nanoflake-based ER fluids that have been engineered as novel, readily synthesizable polymeric gels. Polyethylene glycol (PEG 400) based graphene gels have been synthesized and a very high ER response (∼125 000% enhancement in viscosity under influence of an electric field) has been observed for low concentration systems (∼2 wt.%). The gels overcome several drawbacks innate to ER fluids. The gels exhibit long term stability, a high graphene packing ratio which ensures very high ER response, and the microstructure of the gels ensures that fibrillation of the graphene nanoflakes under an electric field is undisturbed by thermal fluctuations, further leading to mega ER...
December 8, 2016: Nanotechnology
https://www.readbyqxmd.com/read/27926730/integrin-yap-taz-jnk-cascade-mediates-atheroprotective-effect-of-unidirectional-shear-flow
#6
Li Wang, Jiang-Yun Luo, Bochuan Li, Xiao Yu Tian, Li-Jing Chen, Yuhong Huang, Jian Liu, Dan Deng, Chi Wai Lau, Song Wan, Ding Ai, King-Lun Kingston Mak, Ka Kui Tong, Kin Ming Kwan, Nanping Wang, Jeng-Jiann Chiu, Yi Zhu, Yu Huang
The Yorkie homologues YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif, also known as WWTR1), effectors of the Hippo pathway, have been identified as mediators for mechanical stimuli. However, the role of YAP/TAZ in haemodynamics-induced mechanotransduction and pathogenesis of atherosclerosis remains unclear. Here we show that endothelial YAP/TAZ activity is regulated by different patterns of blood flow, and YAP/TAZ inhibition suppresses inflammation and retards atherogenesis...
December 7, 2016: Nature
https://www.readbyqxmd.com/read/27925032/numerical-study-of-wake-characteristics-in-a-horizontal-axis-hydrokinetic-turbine
#7
Paulo A S F Silva, Taygoara F DE Oliveira, Antonio C P Brasil, Jerson R P Vaz
Over the years most studies on wake characteristics have been devoted to wind turbines, while few works are related to hydrokinetic turbines. Among studies applied to rivers, depth and width are important parameters for a suitable design. In this work, a numerical study of the wake in a horizontal-axis hydrokinetic turbine is performed, where the main objective is an investigation on the wake structure, which can be a constraining factor in rivers. The present paper uses the Reynolds Averaged Navier Stokes (RANS) flow simulation technique, in which the Shear-Stress Transport (SST) turbulent model is considered, in order to simulate a free hydrokinetic runner in a typical river flow...
December 1, 2016: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/27924928/unified-rheology-of-vibro-fluidized-dry-granular-media-from-slow-dense-flows-to-fast-gas-like-regimes
#8
Andrea Gnoli, Antonio Lasanta, Alessandro Sarracino, Andrea Puglisi
Granular media take on great importance in industry and geophysics, posing a severe challenge to materials science. Their response properties elude known soft rheological models, even when the yield-stress discontinuity is blurred by vibro-fluidization. Here we propose a broad rheological scenario where average stress sums up a frictional contribution, generalizing conventional μ(I)-rheology, and a kinetic collisional term dominating at fast fluidization. Our conjecture fairly describes a wide series of experiments in a vibrofluidized vane setup, whose phenomenology includes velocity weakening, shear thinning, a discontinuous thinning transition, and gaseous shear thickening...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924433/effect-of-wave-current-interactions-on-sediment-resuspension-in-large-shallow-lake-taihu-china
#9
Yiping Li, Chunyan Tang, Jianwei Wang, Kumud Acharya, Wei Du, Xiaomeng Gao, Liancong Luo, Huiyun Li, Shujun Dai, Jepkirui Mercy, Zhongbo Yu, Baozhu Pan
The disturbance of the water-sediment interface by wind-driven currents and waves plays a critical role in sediment resuspension and internal nutrient release in large, shallow lakes. This study analyzed the effects of the interactions between wind-induced currents an1d waves on the driving mechanism of sediment resuspension in Lake Taihu, the third largest freshwater lake in China, using acoustic and optic techniques to collect long-term, high-frequency, synchronous in situ measurements of wind, currents, waves, and suspended solid concentrations (SSCs)...
December 6, 2016: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/27924309/engineering-the-dynamic-properties-of-protein-networks-through-sequence-variation
#10
Lawrence J Dooling, David A Tirrell
The dynamic behavior of macromolecular networks dominates the mechanical properties of soft materials and influences biological processes at multiple length scales. In hydrogels prepared from self-assembling artificial proteins, stress relaxation and energy dissipation arise from the transient character of physical network junctions. Here we show that subtle changes in sequence can be used to program the relaxation behavior of end-linked networks of engineered coiled-coil proteins. Single-site substitutions in the coiled-coil domains caused shifts in relaxation time over 5 orders of magnitude as demonstrated by dynamic oscillatory shear rheometry and stress relaxation measurements...
November 23, 2016: ACS Central Science
https://www.readbyqxmd.com/read/27924174/feasibility-study-of-computational-fluid-dynamics-simulation-of-coronary-computed-tomography-angiography-based-on-dual-source-computed-tomography
#11
Jing Lu, Jie Yu, Heshui Shi
BACKGROUND: Adding functional features to morphological features offers a new method for non-invasive assessment of myocardial perfusion. This study aimed to explore technical routes of assessing the left coronary artery pressure gradient, wall shear stress distribution and blood flow velocity distribution, combining three-dimensional coronary model which was based on high resolution dual-source computed tomography (CT) with computational fluid dynamics (CFD) simulation. METHODS: Three cases of no obvious stenosis, mild stenosis and severe stenosis in left anterior descending (LAD) were enrolled...
January 2017: Journal of Clinical Medicine Research
https://www.readbyqxmd.com/read/27923974/acute-vascular-effects-of-carbonated-warm-water-lower-leg-immersion-in-healthy-young-adults
#12
Shigehiko Ogoh, Ryohei Nagaoka, Takamasa Mizuno, Shohei Kimura, Yasuhiro Shidahara, Tomomi Ishii, Michinari Kudoh, Erika Iwamoto
Endothelial dysfunction is associated with increased cardiovascular mortality and morbidity; however, this dysfunction may be ameliorated by several therapies. For example, it has been reported that heat-induced increases in blood flow and shear stress enhance endothelium-mediated vasodilator function. Under these backgrounds, we expect that carbon dioxide (CO2)-rich water-induced increase in skin blood flow improves endothelium-mediated vasodilation with less heat stress. To test our hypothesis, we measured flow-mediated dilation (FMD) before and after acute immersion of the lower legs and feet in mild warm (38°C) normal or CO2-rich tap water (1000 ppm) for 20 min in 12 subjects...
December 2016: Physiological Reports
https://www.readbyqxmd.com/read/27923328/modeling-stroma-induced-drug-resistance-in-a-tissue-engineered-tumor-model-of-ewing-sarcoma
#13
Marco Santoro, Brian A Menegaz, Salah-Eddine Lamhamedi-Cherradi, Eric R Molina, Danielle Wu, Waldemar Priebe, Joseph A Ludwig, Antonios G Mikos
Three-dimensional (3D) tumor models are gaining traction in the research community given their capacity to mimic aspects of the tumor microenvironment absent in monolayer systems. In particular, the ability to spatiotemporally control cell placement within ex vivo 3D systems has enabled the study of tumor-stroma interactions. Furthermore, by regulating biomechanical stimuli, one can reveal how biophysical cues affect stromal cell phenotype and how their phenotype impacts tumor drug sensitivity. Both tumor architecture and shear force have profound effects on Ewing sarcoma (ES) cell behavior and are known to elicit ligand-mediated activation of the insulin-like growth factor-1 receptor (IGF-1R), thereby mediating resistance of ES cells to IGF-1R inhibitors...
December 6, 2016: Tissue Engineering. Part A
https://www.readbyqxmd.com/read/27922885/ventricular-assist-device-implantation-configurations-impact-overall-mechanical-circulatory-support-system-thrombogenic-potential
#14
Wei-Che Chiu, Yared Alemu, Allison J McLarty, Shmuel Einav, Marvin J Slepian, Danny Bluestein
Ventricular assist devices (VAD) became in recent years the standard of care therapy for advanced heart failure with hemodynamic compromise. With the steadily growing population of device recipients, various post-implant complications have been reported, mostly associated with the hyper-shear generated by VADs that enhance their thrombogenicity by activating platelets. While VAD design optimization can significantly improve its thromboresistance, the implanted VAD need to be evaluated as part of a system. Several clinical studies indicated that variability in implantation configurations may contribute to the overall system thrombogenicity...
December 2, 2016: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/27920123/selective-enhancement-of-insulin-sensitivity-in-the-endothelium-in-vivo-reveals-a-novel-proatherosclerotic-signalling-loop
#15
Hema Viswambharan, Nadira Y Yuldasheva, Anshuman Sengupta, Helen Imrie, Matthew C Gage, Natalie J Haywood, Andrew M Walker, Anna Skromna, Natalia Makova, Stacey L Galloway, Pooja Shah, Piruthivi Sukumar, Karen E Porter, Peter J Grant, Ajay M Shah, Celio X Santos, Jing Li, David J Beech, Stephen Wheatcroft, Richard M Cubbon, Mark T Kearney
RATIONALE: In the endothelium, insulin stimulates endothelial nitric oxide synthase (eNOS) to generate the anti-atherosclerotic signalling radical NO. Insulin resistant type 2 diabetes is associated with reduced NO availability and accelerated atherosclerosis. The effect of enhancing endothelial insulin sensitivity on NO availability is unclear. OBJECTIVE: To answer this question we generated a mouse with endothelial cell (EC)-specific over-expression of the human insulin receptor (hIRECO) using the Tie2 promoter-enhancer...
December 5, 2016: Circulation Research
https://www.readbyqxmd.com/read/27919417/multidirectional-wss-disturbances-in-stenotic-turbulent-flows-a-pre-and-post-intervention-study-in-an-aortic-coarctation
#16
Magnus Andersson, Jonas Lantz, Tino Ebbers, Matts Karlsson
Wall shear stress (WSS) disturbances are commonly expressed at sites of abnormal flow obstructions and may play an essential role in the pathogenesis of various vascular diseases. In laminar flows these disturbances have recently been assessed by the transverse wall shear stress (transWSS), which accounts for the WSS multidirectionality. Site-specific estimations of WSS disturbances in pulsatile transitional and turbulent type of flows are more challenging due to continuous and unpredictable changes in WSS behavior...
November 28, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27919215/current-strategies-in-modification-of-plga-based-gene-delivery-system
#17
Mohammad Ramezani, Mahboubeh Ebrahimian, Maryam Hashemi
The successful gene therapy has been limited by safe and efficient delivery of nucleic acid to the target cells. Poly (d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) are able to deliver drugs and gene efficiently. This formulation has several advantages in comparison with other formulations including improvement of solubility, stability, controlling of degradation and release of the entrapped agents. For application of PLGA as gene carrier, there exist many challenges. PLGA nanoparticles could protect the encapsulated DNA from in vivo degradation but the DNA release is slowl and their negative charge acts as a barrier to DNA incorporation and delivery...
December 5, 2016: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/27918892/the-effects-of-muscle-weakness-on-degenerative-spondylolisthesis-a-finite-element-study
#18
Rui Zhu, Wen-Xin Niu, Zhi-Li Zeng, Jian-Hua Tong, Zhi-Wei Zhen, Shuang Zhou, Yan Yu, Li-Ming Cheng
BACKGROUND: Whether muscle weakness is a cause, or result, of degenerative spondylolisthesis is not currently well understood. Little biomechanical evidence is available to offer an explanation for the mechanism behind exercise therapy. Therefore, the aim of this study is to investigate the effects of back muscle weakness on degenerative spondylolisthesis and to tease out the biomechanical mechanism of exercise therapy. METHODS: A nonlinear 3-D finite element model of L3-L5 was constructed...
November 26, 2016: Clinical Biomechanics
https://www.readbyqxmd.com/read/27918290/nacre-mimetic-bulk-lamellar-composites-reinforced-with-high-aspect-ratio-glass-flakes
#19
Selen N Gurbuz Guner, Arcan F Dericioglu
Nacre-mimetic epoxy matrix composites reinforced with readily available micron-sized high aspect ratio C-glass flakes were fabricated by a relatively simple, single-step, scalable, time, cost and man-power effective processing strategy: hot-press assisted slip casting (HASC). HASC enables the fabrication of preferentially oriented two-dimensional inorganic reinforcement-polymer matrix bulk lamellar composites with a micro-scale structure resembling the brick-and-mortar architecture of nacre. By applying the micro-scale design guideline found in nacre and optimizing the relative volume fractions of the reinforcement and the matrix as well as by anchoring the brick-and-mortar architecture, and tailoring the interface between reinforcements and the matrix via silane coupling agents, strong, stiff and tough bio-inspired nacre-mimetic bulk composites were fabricated...
December 5, 2016: Bioinspiration & Biomimetics
https://www.readbyqxmd.com/read/27916240/spatial-phenotyping-of-the-endocardial-endothelium-as-a-function-of-intracardiac-hemodynamic-shear-stress
#20
Margaret E McCormick, Elisabetta Manduchi, Walter R T Witschey, Robert C Gorman, Joseph H Gorman, Yi-Zhou Jiang, Christian J Stoeckert, Alex J Barker, Samuel Yoon, Michael Markl, Peter F Davies
Despite substantial evidence for the central role of hemodynamic shear stress in the functional integrity of vascular endothelial cells, hemodynamic and molecular regulation of the endocardial endothelium lining the heart chambers remains understudied. We propose that regional differences in intracardiac hemodynamics influence differential endocardial gene expression leading to phenotypic heterogeneity of this cell layer. Measurement of intracardiac hemodynamics was performed using 4-dimensional flow MRI in healthy humans (n=8) and pigs (n=5)...
November 16, 2016: Journal of Biomechanics
keyword
keyword
25915
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"