Investigating the mechanotransduction of transient shear stress mediated by Piezo1 ion channel using a 3D printed dynamic gravity pump

Serial femtosecond crystallography (SFX) using X-ray free-electron laser (FEL) sources has the potential to determine the structures of macromolecules beyond the limitation of radiation damage and without the need for crystals of sufficient size for conventional crystallography. In SFX, a liquid microjet is used to inject randomly oriented crystals suspended in their storage solution into the FEL beam. Settling of crystals in the reservoir prior to the injection has been found to complicate the data collection. This article details the development of an anti-settling sample delivery instrument based on a rotating syringe pump, capable of producing flow rates and liquid pressures necessary for the operation of the injector. The device has been used successfully with crystals of different proteins, with crystal sizes smaller than 20 µm. Even after hours of continuous operation, no significant impairment of the experiments due to sample settling was observed. This article describes the working principle of the instrument and sets it in context with regard to the experimental conditions used for SFX. Hit rates for longer measuring periods are compared with and without the instrument operating. Two versions of the instrument have been developed, which both deliver sample at a constant flow rate but which differ in their minimum liquid flow rates and maximum pressures.

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Effects of capillary number and flow rates on the hydrodynamics of droplet generation in two-phase cross-flow microfluidic systems

Journal of the Taiwan Institute of Chemical Engineers ◽

10.1016/j.jtice.2021.07.045 ◽

2021 ◽

Author(s):

Akepogu Venkateshwarlu ◽

Ram Prakash Bharti

Keyword(s):

Capillary Number ◽

Cross Flow ◽

Droplet Generation ◽

Microfluidic Systems ◽

Two Phase ◽

Flow Rates

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Genetic correlates of wall shear stress in a patient-specific 3D-printed cerebral aneurysm model

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2018-014669 ◽

2019 ◽

Vol 11 (10) ◽

pp. 999-1003 ◽

Cited By ~ 6

Author(s):

Michael R Levitt ◽

Christian Mandrycky ◽

Ashley Abel ◽

Cory M Kelly ◽

Samuel Levy ◽

...

Keyword(s):

Endothelial Cells ◽

Shear Stress ◽

Wall Shear Stress ◽

Cerebral Aneurysm ◽

Cell Morphology ◽

Patient Specific ◽

Parent Vessel ◽

3D Printed ◽

Wall Shear ◽

Dynamics Simulations

ObjectivesTo study the correlation between wall shear stress and endothelial cell expression in a patient-specific, three-dimensional (3D)-printed model of a cerebral aneurysm.Materials and methodsA 3D-printed model of a cerebral aneurysm was created from a patient’s angiogram. After populating the model with human endothelial cells, it was exposed to media under flow for 24 hours. Endothelial cell morphology was characterized in five regions of the 3D-printed model using confocal microscopy. Endothelial cells were then harvested from distinct regions of the 3D-printed model for mRNA collection and gene analysis via quantitative polymerase chain reaction (qPCR.) Cell morphology and mRNA measurement were correlated with computational fluid dynamics simulations.ResultsThe model was successfully populated with endothelial cells, which survived under flow for 24 hours. Endothelial morphology showed alignment with flow in the proximal and distal parent vessel and aneurysm neck, but disorganization in the aneurysm dome. Genetic analysis of endothelial mRNA expression in the aneurysm dome and distal parent vessel was compared with the proximal parent vessels. ADAMTS-1 and NOS3 were downregulated in the aneurysm dome, while GJA4 was upregulated in the distal parent vessel. Disorganized morphology and decreased ADAMTS-1 and NOS3 expression correlated with areas of substantially lower wall shear stress and wall shear stress gradient in computational fluid dynamics simulations.ConclusionsCreating 3D-printed models of patient-specific cerebral aneurysms populated with human endothelial cells is feasible. Analysis of these cells after exposure to flow demonstrates differences in both cell morphology and genetic expression, which correlate with areas of differential hemodynamic stress.

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PIV Measurements of Flow in a Centrifugal Blood Pump: Steady Flow

Journal of Biomechanical Engineering ◽

10.1115/1.1865189 ◽

2004 ◽

Vol 127 (2) ◽

pp. 244-253 ◽

Cited By ~ 18

Author(s):

Steven W. Day ◽

James C. McDaniel

Keyword(s):

Shear Stress ◽

Artificial Heart ◽

Heart Valves ◽

Blood Pump ◽

Reynolds Stresses ◽

Centrifugal Blood Pump ◽

Flow Rates ◽

Blood Damage ◽

Artificial Heart Valves ◽

Stagnant Flow

Magnetically suspended left ventricular assist devices have only one moving part, the impeller. The impeller has absolutely no contact with any of the fixed parts, thus greatly reducing the regions of stagnant or high shear stress that surround a mechanical or fluid bearing. Measurements of the mean flow patterns as well as viscous and turbulent (Reynolds) stresses were made in a shaft-driven prototype of a magnetically suspended centrifugal blood pump at several constant flow rates (3–9L∕min) using particle image velocimetry (PIV). The chosen range of flow rates is representative of the range over which the pump may operate while implanted. Measurements on a three-dimensional measurement grid within several regions of the pump, including the inlet, blade passage, exit volute, and diffuser are reported. The measurements are used to identify regions of potential blood damage due to high shear stress and∕or stagnation of the blood, both of which have been associated with blood damage within artificial heart valves and diaphragm-type pumps. Levels of turbulence intensity and Reynolds stresses that are comparable to those in artificial heart valves are reported. At the design flow rate (6L∕min), the flow is generally well behaved (no recirculation or stagnant flow) and stress levels are below levels that would be expected to contribute to hemolysis or thrombosis. The flow at both high (9L∕min) and low (3L∕min) flow rates introduces anomalies into the flow, such as recirculation, stagnation, and high stress regions. Levels of viscous and Reynolds shear stresses everywhere within the pump are below reported threshold values for damage to red cells over the entire range of flow rates investigated; however, at both high and low flow rate conditions, the flow field may promote activation of the clotting cascade due to regions of elevated shear stress adjacent to separated or stagnant flow.

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A capillary suction pump giving constant flow rates

Analytica Chimica Acta ◽

10.1016/s0003-2670(00)84549-3 ◽

1988 ◽

Vol 209 ◽

pp. 57-67 ◽

Cited By ~ 3

Author(s):

M.J. Eddowes

Keyword(s):

Constant Flow ◽

Capillary Suction ◽

Flow Rates ◽

Suction Pump

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Tracer Gas Mapping of a Beverage Cart Wake in a Twin Aisle Aircraft Cabin

Volume 6: Fluids and Thermal Systems; Advances for Process Industries, Parts A and B ◽

10.1115/imece2011-62760 ◽

2011 ◽

Cited By ~ 2

Author(s):

A. Tristan Trupka ◽

Mohammad H. Hosni ◽

Byron W. Jones

Keyword(s):

Contaminant Transport ◽

Heat Load ◽

Constant Flow ◽

Outdoor Air ◽

Tracer Gas ◽

Flow Rates ◽

Constant Flow Rate ◽

Co2 Level ◽

Carbon Dioxide Co2 ◽

Injection Location

An experimental study is performed in a mockup Boeing 767 cabin section consisting of eleven rows with seven seats per row. Carbon Dioxide (CO2) tracer gas is injected at a constant flow rate at a location of interest until concentrations in the cabin reach steady state. Ventilation equipment and flow rates representative of an actual aircraft are used for all experiments. Seats in the mockup are occupied by thermal manikins to simulate passenger heat load. A motorized beverage cart traverses the length of the cabin aisle passing by the injection location. The concentrations of tracer gas displaced by the cart are measured at locations throughout the cabin. Comparing these measurements to baseline readings taken with no cart movement, a map of the degree to which contaminant transport is affected by the beverage cart is calculated. The cabin mockup is supplied by 100% outdoor air through actual Boeing supply ductwork and linear diffusers along the cabin length above the aisles. The CO2 level is measured in the inlet air, measurement locations in the cabin, and exhaust air using nondispersive infrared (NDIR) sensors. Measured results are reported for all (54) seat locations downstream of the cart traverse/injection location for an injection location near the rear of the cabin. Analogous measurements are also conducted examining the effect of variation in cart speed and modified injection location.

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Mechano‐sensitivity of epithelial sodium channels (ENaCs): laminar shear stress increases ion channel open probability

The FASEB Journal ◽

10.1096/fj.06-7694com ◽

2007 ◽

Vol 21 (10) ◽

pp. 2389-2399 ◽

Cited By ~ 82

Author(s):

Mike Althaus ◽

Roman Bogdan ◽

Wolfgang G. Clauss ◽

Martin Fronius

Keyword(s):

Shear Stress ◽

Ion Channel ◽

Sodium Channels ◽

Laminar Shear Stress ◽

Epithelial Sodium Channels ◽

Open Probability ◽

Laminar Shear

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Flow-induced vasodilation in the ferret lung

Journal of Applied Physiology ◽

10.1152/jappl.1997.83.2.495 ◽

1997 ◽

Vol 83 (2) ◽

pp. 495-502 ◽

Cited By ~ 13

Author(s):

Joseph H. Chammas ◽

David. A. Rickaby ◽

Margarita Guarin ◽

John H. Linehan ◽

Christopher C. Hanger ◽

...

Keyword(s):

Shear Stress ◽

Venous Pressure ◽

Pulmonary Arteries ◽

Flow Rates ◽

Hypoxic Conditions ◽

Pulmonary Vasodilator ◽

X Ray Imaging ◽

Pulmonary Arterial ◽

Arterial Tone ◽

Intravascular Pressure

Chammas, Joseph H., David. A. Rickaby, Margarita Guarin, John H. Linehan, Christopher C. Hanger, and Christopher A. Dawson.Flow-induced vasodilation in the ferret lung. J. Appl. Physiol. 83(2): 495–502, 1997.—To examine the possibility that shear stress may be a pulmonary vasodilator stimulus, we studied the effect of changing blood flow on the diameters of small pulmonary arteries in isolated perfused ferret lung lobes. The arteries studied were in the ∼0.3- to 1.3-mm-diameter range, and the diameters were measured by using microfocal X-ray imaging. The diameters were measured at two flow rates, 10 and 40 ml/min, with the intravascular pressure in the measured vessels the same at the two flow rates as the result of venous pressure adjustment. The response to a change in flow was studied under both normoxic and hypoxic conditions. Hypoxia was used to elevate pulmonary arterial tone to increase the likelihood of detecting a vasodilator response. Under normoxic conditions, changing flow had little effect on the arterial diameters, but under hypoxic conditions the arteries were consistently larger at the higher flow than at the lower flow, even though the distending pressure was the same at the two flow rates. The results are consistent with the hypothesis that shear stress is a pulmonary vasodilator stimulus.

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