Shear gradient in longissimus steaks

2002 ◽  
Vol 80 (9) ◽  
pp. 2390 ◽  
Author(s):  
C. R. Kerth ◽  
J. L. Montgomery ◽  
J. L. Lansdell ◽  
C. B. Ramsey ◽  
M. F. Miller
Keyword(s):  
Shear Gradient

Behavior of a Charged Vesicle System under the Influence of a Shear Gradient:  A Microstructural Study

1998 ◽  
Vol 102 (16) ◽  
pp. 2837-2840 ◽  
Author(s):  
M. Bergmeier ◽  
M. Gradzielski ◽  
H. Hoffmann ◽  
K. Mortensen
Keyword(s):  
Microstructural Study ◽  
Shear Gradient

scholarly journals Patient-Specific Adhesion of Sickle Red Blood Cells in Shear-Gradient Microscale Flow

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 964-964
Author(s):  
Erdem Kucukal ◽  
Jane A. Little ◽  
Umut A. Gurkan
Keyword(s):  
Shear Rate ◽  
Blood Cell ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Flow Direction ◽  
Patient Specific ◽  
Shear Rates ◽  
Microscale Flow ◽  
Shear Gradient ◽  
Equity Ownership

Abstract The pathophysiology of sickle cell disease (SCD) involves altered biophysical properties of red blood cells (RBCs) and increased cellular adhesion, which can synergistically trigger recurrent and painful vaso-occlusive events in the microcirculatory network. RBC adhesion to the endothelial wall is heterogeneous and may initiate such occlusions by disrupting the local flow thus activating platelets and promoting subsequent cell-cell interactions. Moreover, these episodic events take place within a wide range of dynamically changing shear rates at the microscale. In order to better understand the role of shear rate on this process, we quantified shear-dependent RBC adhesion to endothelial proteins fibronectin (FN) and laminin (LN) utilizing a microfluidic system that can simulate physiologically relevant shear gradients of microcirculatory blood flow at a single flow rate. Whole blood samples were collected from 20 patients (10 males and 10 females) with homozygous SCD (HbSS). Samples were perfused through FN and LN immobilized shear-gradient microchannels (Fig. 1A) in which the shear rate continuously changes along flow direction. Computational simulations characterized the flow dynamics near the adherent RBCs (Fig. 1B). Based on the numerical results, a rectangular "field of interest (FOI)", along which the shear rate dropped approximately three-fold, was chosen for quantification of shear-dependent RBC adhesion. We observed changes in RBC adhesion to LN and FN in the shear gradient flow. Figure 1C and 1D show typical adhesion curves of surface adherent RBCs for an individual SCD sample within the FOI. To assess patient specific shear-dependent adhesion, we defined a parameter, "shear dependent adhesion rate (SDAR)", which is the slope of the adhesion curves based on normalized RBC adhesion numbers. A higher SDAR value was indicative of marked numbers of adherent RBCs that detach at higher shear rates whereas the effect of shear rate on RBC detachment was less for a lower SDAR. We observed an inverse relationship between SDAR and number of persistently adherent RBCs at high shear rates. Shear-dependent RBC adhesion to LN was heterogeneous among SCD patients. Patients with higher WBC counts constituted the low SDAR population with a threshold SDAR value of 60 (Fig. 1E, p=0.005, ANOVA). WBCs from patients with higher SDARs (and fewer persistently adhered cells) were all within the normal range. Patients in the low SDAR group also had significantly elevated absolute neutrophil counts (Fig. 1F, p=0.006, ANOVA), and ferritin levels (Fig. 1G, p=0.007, ANOVA). The mean ferritin level of those with low SDAR was nearly ten times greater than normal (mean= [3272.3 ± 791.9] μg/L vs. [784.5±219.6] μg/L). No white blood cell (WBC) adhesion was observed in the experiments. Here, we report a novel shear dependent adhesion ratio of sickle RBCs utilizing LN and FN functionalized microchannels. The approach presented here enabled us to create a shear gradient throughout the channel which may simulate the physiological flow conditions in the post-capillary venules. We further analyzed shear-dependent RBC adhesion in a patient specific manner and identified patient groups with low and high SDAR. The findings also suggested a link between lower shear dependent sickle RBC adhesion to LN and patient clinical phenotypes including inflammation and iron overload. Acknowledgments: This work was supported by grant #2013126 from the Doris Duke Charitable Foundation, National Heart Lung and Blood Institute R01HL133574, and National Science Foundation CAREER Award 1552782. Figure 1: Shear-dependent sickle RBC adhesion in microscale flow. (A) Macroscopic image of the shear-gradient microchannel with the arrow indicating flow direction. (B) Velocity and shear rate contours on a 2D plane above the bottom surface. The dashed rectangular area indicates the field of interest (FOI) where the experimental data were obtained. (C, D) Typical distribution of adherent deformable and non-deformable RBCs in LN and FN functionalized microchannels with the shear gradient. Dashed lines represent the adhesion curves and the corresponding equations were used to quantify shear dependent adhesion data. Shear-dependent RBC adhesion was lower (nSDAR<60) in patients with elevated white blood cell counts (E), absolute neutrophil counts (F), and serum ferritin levels (G). The dashed rectangles indicate the normal clinical values. Figure 1 Figure 1. Disclosures Little: Hemex Health: Equity Ownership. Gurkan: Hemex Health: Employment, Equity Ownership.

GRAFT COPOLYMERS OF STYRENE AND METHYL METHACRYLATE: PART II: VISCOSITY BEHAVIOR

1956 ◽  
Vol 34 (8) ◽  
pp. 1027-1036 ◽  
Author(s):  
M. H. Jones
Keyword(s):  
Shear Rate ◽  
Methyl Methacrylate ◽  
Graft Copolymers ◽  
Free Fall ◽  
Capillary Viscometer ◽  
Linear Polymers ◽  
Viscosity Behavior ◽  
Shear Gradient ◽  
Constant Shear Rate ◽  
Made In

A study of the viscosity behavior of the graft copolymers described in Part I has been made with dilute solutions in benzene at 25 °C. Although the slope constants of the Huggins equation increase with the frequency of branching when measurements are made in a capillary viscometer under 'free fall' conditions, this is shown to be attributable to the dependence of viscosity on shear gradient. At a constant shear rate, the Huggins k′ values approximate to those of linear polymers. It is suggested that the marked increase in viscosity observed with decreasing shear rate for the graft copolymers is due to molecular entanglement.

Shear Effects in Hot-Wire Measurements

1976 ◽  
Vol 98 (4) ◽  
pp. 771-773 ◽  
Author(s):  
Ronald M. C. So
Keyword(s):  
Lift Force ◽  
Viscous Sublayer ◽  
Diameter Ratio ◽  
Two Dimensional ◽  
Wire Length ◽  
Hot Wire ◽  
True Position ◽  
Shear Gradient ◽  
Shear Effects ◽  
The Wire

When a circular cylinder is placed in a two-dimensional shear flow, a lift force is experienced by the cylinder. In the case of hot-wire measurements in the viscous sublayer, this will give rise to a displacement of the wire from its true position. The resultant measurements are found to be in error if the wire length to diameter ratio is > 300 and the shear gradient of the flow is large.

scholarly journals Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows

2016 ◽  
Vol 371 (1704) ◽  
pp. 20150391 ◽  
Author(s):  
Douglas R. Warrick ◽  
Tyson L. Hedrick ◽  
Andrew A. Biewener ◽  
Kristen E. Crandell ◽  
Bret W. Tobalske
Keyword(s):  
Wind Speed ◽  
High Speed ◽  
Ground Effect ◽  
Natural State ◽  
Wingbeat Frequency ◽  
High Speeds ◽  
Aerial Insectivores ◽  
Video Systems ◽  
Shear Gradient ◽  
Barn Swallows

While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows ( Hirundo rustica ) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3–2.0 m s −1 across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02–6.1 m s −1 . While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight'.

scholarly journals A shear gradient-activated microfluidic device for automated monitoring of whole blood haemostasis and platelet function

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Abhishek Jain ◽  
Amanda Graveline ◽  
Anna Waterhouse ◽  
Andyna Vernet ◽  
Robert Flaumenhaft ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Platelet Function ◽  
Whole Blood ◽  
Automated Monitoring ◽  
Shear Gradient

scholarly journals From weakly adhesive to highly thrombogenic: the shear gradient switch

Haematologica ◽  
2020 ◽  
Vol 105 (10) ◽  
pp. 2355-2357
Author(s):  
Yathreb Asaad ◽  
Netanel Korin
Keyword(s):  
Shear Gradient

Lateral migration of vesicles in microchannels: effects of walls and shear gradient

2009 ◽  
pp. 112-119 ◽  
Author(s):  
Badr Kaoui ◽  
Gwennou Coupier ◽  
Chaouqi Misbah ◽  
Thomas Podgorski
Keyword(s):  
Lateral Migration ◽  
Shear Gradient
Sign in / Sign up

Export Citation Format

Share Document