Flow Measurements in an Atherosclerotic Curved, Tapered Femoral Artery Model of Man

1988 ◽  
Vol 110 (4) ◽  
pp. 310-319 ◽  
Author(s):  
L. H. Back ◽  
E. Y. Kwack ◽  
D. W. Crawford
Keyword(s):  
Flow Simulation ◽  
Reynolds Numbers ◽  
Flow Measurements ◽  
Pressure Drops ◽  
Physiological Conditions ◽  
Curvature Effects ◽  
Smooth Model ◽  
Lesion Localization ◽  
Flow Resistances

Flow visualization and pressure measurements were made for physiological conditions in a model derived from a femoral angiorgram of a patient with lesion localization on the inner curvature wall and with vessel taper. Effects of curvature and taper were evaluated separately in other curved, tapered, smooth and straight, tapered, smooth models. Double helical secondary flow patterns were modified by plaque on the inner wall, and flow separations were observed between plaques at higher flow rates and Reynolds numbers. Pressure drop data for the plaque simulation model were similar in trend with Reynolds number as for the smooth model, but flow resistances were 25 to 40 percent higher. Significant pressure drops were measured due to the mild taper which could be estimated from momentum considerations, and smaller increased pressure drops were found due to curvature effects at the higher Dean numbers. Flow resistances for in vivo pulsatile flow simulation were about 10 percent higher than for steady flow for the plaque model, whereas no differences were observed for the smooth model.

Flow Measurements in a Human Femoral Artery Model With Reverse Lumen Curvature

1988 ◽  
Vol 110 (4) ◽  
pp. 300-309 ◽  
Author(s):  
L. H. Back ◽  
M. R. Back ◽  
E. Y. Kwack ◽  
D. W. Crawford
Keyword(s):  
Steady Flow ◽  
Femoral Artery ◽  
Flow Simulation ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Reverse Direction ◽  
Flow Measurements ◽  
Left Femoral Artery ◽  
Lesion Localization ◽  
Made In

Flow visualization and wall pressure measurements were made in a smooth reverse curvature model that conformed to the gentle “s” shape of a left femoral artery angiogram of a patient in a clinical trial. Observed lesion localization at the inner (lesser) curvatures appeared to be associated with secondary flows in the wall vicinity directed toward the inner curvatures that tended to reverse direction in the flow entering the reverse curvature region. Moderate flow resistance increases of about 20 percent above the Poiseuille flow relation were found at the higher physiological Reynolds numbers Re above about 600–700 and thus Dean numbers for steady flow. For pulsatile flow simulation, flow resistances did not increase up to the largest Re of 470 tested. Apparently, the large variations in velocity during the cardiac cycle disrupted the stronger secondary flow patterns observed at the higher Reynolds numbers for steady flow.

Large-Eddy Turbulent Flow Simulation of a KOMAX Static Mixer

2008 ◽  
Author(s):  
Ramin K. Rahmani ◽  
Theo G. Keith ◽  
Anahita Ayasoufi
Keyword(s):  
Turbulent Flow ◽  
Critical Role ◽  
Flow Simulation ◽  
Reynolds Numbers ◽  
Static Mixer ◽  
Viscous Liquids ◽  
Pressure Drops ◽  
Static Mixers ◽  
Eddy Simulation ◽  
Large Eddy

Viscous liquids have to be homogenized in continuous operations in many branches of processing industries; and therefore, fluid mixing plays a critical role in the success or failure of many industrial processes. Consequences of improper mixing include non-reproducible processing conditions and lowered product quality, resulting in the need for more elaborate downstream processes and increased costs. The range of practical flow Reynolds numbers for KOMAX static mixers in industry is usually from moderate values (Re ≈ 0) to very large values (e.g. Re ≈ 5,000,000). However, most of industrial applicants have a very small flow to moderate Reynolds numbers (e.g. Re ≈ 5,000). This paper presents an improved understanding of the turbulent flow pattern for single-phase liquids through the mixer. Large-Eddy Simulation (LES) model is applied to the flow in a KOMAX static mixer to calculate the flow velocities, pressure drops, etc. Using a variety of predictive tools, the mixing results are obtained.

Supramolecular Enhancement of Aminoxyl ORCA Contrast Agents

2019 ◽  
Author(s):  
Hamilton Lee ◽  
Jenica Lumata ◽  
Michael A. Luzuriaga ◽  
Candace Benjamin ◽  
Olivia Brohlin ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Side Effects ◽  
Magnetic Resonance ◽  
Tobacco Mosaic Virus ◽  
Contrast Agents ◽  
Single Molecule ◽  
Organic Radical ◽  
Resonance Imaging ◽  
Physiological Conditions

<div><div><div><p>Many contrast agents for magnetic resonance imaging are based on gadolinium, however side effects limit their use in some patients. Organic radical contrast agents (ORCAs) are potential alternatives, but are reduced rapidly in physiological conditions and have low relaxivities as single molecule contrast agents. Herein, we use a supramolecular strategy where cucurbit[8]uril binds with nanomolar affinities to ORCAs and protects them against biological reductants to create a stable radical in vivo. We further over came the weak contrast by conjugating this complex on the surface of a self-assembled biomacromolecule derived from the tobacco mosaic virus.</p></div></div></div>

In-vivo anti-oxidant screening of Tectona grandis extract

2020 ◽  
Vol 9 (1) ◽  
pp. 1-4
Author(s):  
Tamilarasi G P ◽  
Sabarees G
Keyword(s):  
Biochemical Parameters ◽  
Tectona Grandis ◽  
The Body ◽  
Altered Expression ◽  
Physiological Conditions ◽  
Synthetic Drugs ◽  
Significant Difference ◽  
Anti Oxidant ◽  
Radical Generation

Oxidation is an essential reaction in the human body, which determines the expression of proteins in the body. This results in the altered expression like rapid growth resulting in cancers and other disorders. Many synthetic drugs are available in the market that is effective in limiting the free radical generation and the reaction of radicals with cells. Unfortunately, all those synthetic drugs were found to cause side effects and adverse effects in the body. But given the accuracy of the predictability of the results and administration, this research focuses on testing the anti-oxidant efficiency in rat models testing the biochemical parameters. Investigations have also been done on the anti-oxidant activity of Tectona, but every research was concentrated to prove the anti-oxidant activity only. extract had been tested for anti-oxidant activity by estimating various tissue parameters and it showed better activity. As predicted, there is a significant difference in the and results which can be explained are due to the physiological conditions that exist inside the body.

scholarly journals N-Terminomics Strategies for Protease Substrates Profiling

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4699
Author(s):  
Mubashir Mintoo ◽  
Amritangshu Chakravarty ◽  
Ronak Tilvawala
Keyword(s):  
Mass Spectrometry ◽  
Protease Activity ◽  
Viral Infections ◽  
Mass Spectrometry Analysis ◽  
Post Translational Modification ◽  
Spectrometry Analysis ◽  
Physiological Conditions ◽  
Inflammatory Conditions ◽  
Biological Mixtures

Proteases play a central role in various biochemical pathways catalyzing and regulating key biological events. Proteases catalyze an irreversible post-translational modification called proteolysis by hydrolyzing peptide bonds in proteins. Given the destructive potential of proteolysis, protease activity is tightly regulated. Dysregulation of protease activity has been reported in numerous disease conditions, including cancers, neurodegenerative diseases, inflammatory conditions, cardiovascular diseases, and viral infections. The proteolytic profile of a cell, tissue, or organ is governed by protease activation, activity, and substrate specificity. Thus, identifying protease substrates and proteolytic events under physiological conditions can provide crucial information about how the change in protease regulation can alter the cellular proteolytic landscape. In recent years, mass spectrometry-based techniques called N-terminomics have become instrumental in identifying protease substrates from complex biological mixtures. N-terminomics employs the labeling and enrichment of native and neo-N-termini peptides, generated upon proteolysis followed by mass spectrometry analysis allowing protease substrate profiling directly from biological samples. In this review, we provide a brief overview of N-terminomics techniques, focusing on their strengths, weaknesses, limitations, and providing specific examples where they were successfully employed to identify protease substrates in vivo and under physiological conditions. In addition, we explore the current trends in the protease field and the potential for future developments.

scholarly journals A review of the ethnomedicinal, antimicrobial, and phytochemical properties of Musa paradisiaca (plantain)

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Kamoldeen Abiodun Ajijolakewu ◽  
Abiodun Saheed Ayoola ◽  
Tariq Oluwakunmi Agbabiaka ◽  
Folashade Rahmat Zakariyah ◽  
Nike Risikat Ahmed ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Traditional Medicine ◽  
Developed Countries ◽  
Main Body ◽  
Physiological Conditions ◽  
Musa Paradisiaca ◽  
Scientific Justification ◽  
Pharmaceutical Industries ◽  
Developing And Developed Countries

Abstract Background More people—in both developing and developed countries—now use, and are favourably disposed to, traditional medicine. Musa paradisiaca (plantain) is used extensively in traditional medicine across continents. In this review, we investigated the scientific justification of this extensive usage. Main body Generally, several studies validate usage in infectious diseases, but limited antiviral and in vivo reports exist. The mechanistic elicitation of antimicrobial activity has similarly not been ascertained. Contrarily, data abound from rigorous studies on physiological conditions. Activity across categories is tied to the potent phytosterols duo of stigmasterol and β-sitosterol; and the triterpenes viz. cycloeucalenone, 24-methylene-cycloartanol, and 31-norcyclolaudenone; present in plantain. Toxicity studies, while finite, suggest general safety and tolerance. Conclusions Findings in the studies reviewed projects plantain as a veritable source for drug bioprospecting that will be of benefit to scientific research and pharmaceutical industries.

scholarly journals On the Scope of Lagrangian Vortex Methods for Two-Dimensional Flow Simulations and the POD Technique Application for Data Storing and Analyzing

Entropy ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 118
Author(s):  
Kseniia Kuzmina ◽  
Ilia Marchevsky ◽  
Irina Soldatova ◽  
Yulia Izmailova
Keyword(s):  
Flow Simulation ◽  
Internal Flow ◽  
Reynolds Numbers ◽  
Circular Cylinders ◽  
Vortex Methods ◽  
Flow Simulations ◽  
Additional Information ◽  
Two Dimensional Flow ◽  
Different Shapes ◽  
Problem Formulations

The possibilities of applying the pure Lagrangian vortex methods of computational fluid dynamics to viscous incompressible flow simulations are considered in relation to various problem formulations. The modification of vortex methods—the Viscous Vortex Domain method—is used which is implemented in the VM2D code developed by the authors. Problems of flow simulation around airfoils with different shapes at various Reynolds numbers are considered: the Blasius problem, the flow around circular cylinders at different Reynolds numbers, the flow around a wing airfoil at the Reynolds numbers 104 and 105, the flow around two closely spaced circular cylinders and the flow around rectangular airfoils with a different chord to the thickness ratio. In addition, the problem of the internal flow modeling in the channel with a backward-facing step is considered. To store the results of the calculations, the POD technique is used, which, in addition, allows one to investigate the structure of the flow and obtain some additional information about the properties of flow regimes.

Abstract 89: MitoTimer Mouse: a Novel Tool for the Study of Mitochondrial Turnover in vivo

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Aleksandr B Stotland ◽  
Jennifer Ramil ◽  
Roberta A Gottlieb
Keyword(s):  
Cardiac Tissue ◽  
Fluorescent Protein ◽  
Signal Sequence ◽  
Green Fluorescence ◽  
Physiological Conditions ◽  
High Membrane Potential ◽  
Mitochondrial Turnover ◽  
Single Mitochondrion ◽  
Degree Of Heterogeneity

In order to study mitochondrial turnover at the level of a single mitochondrion, our laboratory has developed the MitoTimer protein. Timer is a mutant of DsRed fluorescent protein developed by Terskikh et al. The Timer protein transitions from green fluorescence to a more stable red conformation as it matures over a span of 48 h. Furthermore, the protein is very stable under physiological conditions, insensitive to variations in ionic strength, and changes in pH between 7.0 and 8.0. Notably, Timer maturation from green to red is significantly slowed in deoxygenated buffer, suggesting that molecular oxygen plays a part in fluorophore maturation. We fused the Timer protein with the mitochondrial signal sequence from the cytochrome c oxidase subunit VIII (COX8) to target the protein to the inner membrane of the mitochondria, and further cloned the protein into a construct with a cardiac-restricted α-myosin heavy chain promoter. This construct was used to create the α-MHC MitoTimer mice. Surprisingly, initial analysis of the hearts from these mice reveals a remarkable degree of heterogeneity in the ratio of red-to- green fluorescence of MitoTimer in cardiac tissue. Furthermore, individual mitochondria within cardiomyocytes display a higher red-to-green fluorescence, implying a block in import of newly synthesized MitoTimer that would be caused by the lack of a high membrane potential, indicative of older, dysfunctional mitochondria. Initial studies suggest that these mice represent an elegant tool for the investigation of mitochondrial turnover in the heart.

Selective recruitment of arrestin-3 to clathrin coated pits upon stimulation of G protein-coupled receptors

2000 ◽  
Vol 113 (13) ◽  
pp. 2463-2470 ◽  
Author(s):  
F. Santini ◽  
R.B. Penn ◽  
A.W. Gagnon ◽  
J.L. Benovic ◽  
J.H. Keen
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Coated Pits ◽  
Over Expression ◽  
Physiological Conditions ◽  
A Cell ◽  
G Protein Coupled ◽  
Comparable Magnitude

Non-visual arrestins (arrestin-2 and arrestin-3) play critical roles in the desensitization and internalization of many G protein-coupled receptors. In vitro experiments have shown that both non-visual arrestins bind with high and approximately comparable affinities to activated, phosphorylated forms of receptors. They also exhibit high affinity binding, again of comparable magnitude, to clathrin. Further, agonist-promoted internalization of many receptors has been found to be stimulated by exogenous over-expression of either arrestin2 or arrestin3. The existence of multiple arrestins raises the question whether stimulated receptors are selective for a specific endogenous arrestin under more physiological conditions. Here we address this question in RBL-2H3 cells, a cell line that expresses comparable levels of endogenous arrestin-2 and arrestin-3. When (beta)(2)-adrenergic receptors are stably expressed in these cells the receptors internalize efficiently following agonist stimulation. However, by immunofluorescence microscopy we determine that only arrestin-3, but not arrestin-2, is rapidly recruited to clathrin coated pits upon receptor stimulation. Similarly, in RBL-2H3 cells that stably express physiological levels of m1AChR, the addition of carbachol selectively induces the localization of arrestin-3, but not arrestin-2, to coated pits. Thus, this work demonstrates coupling of G protein-coupled receptors to a specific non-visual arrestin in an in vivo setting.

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