Stokes' law, viscometry, and the Stokes falling sphere clock

Cartwright, Julyan H. E.

doi:10.1098/rsta.2020.0214

Cited by 16 publications

(6 citation statements)

References 24 publications

(33 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…To validate our hypothesis, we first conducted a gravity-driven sedimentation experiment using stationary phase S. aureus cells to quantitatively evaluate if there is a difference in the rate of sedimentation among the cells in an isogenic population. Based on Stokes' law [32], the sedimentation rate (v) is proportional to the buoyant density (B) of cells. Hence, the faster sedimentation rate represents higher buoyant density.…”

Section: For Any Isogenic S Aureus Population There Was a Distributio...mentioning

confidence: 99%

Role of Staphylococcus aureus’s Buoyant Density in the Development of Biofilm Associated Antibiotic Susceptibility

Kispert,

Liguori,

Velikaneye

et al. 2024

Microorganisms

View full text Add to dashboard Cite

Biofilms are clusters of microorganisms that form at various interfaces, including those between air and liquid or liquid and solid. Due to their roles in enhancing wastewater treatment processes, and their unfortunate propensity to cause persistent human infections through lowering antibiotic susceptibility, understanding and managing bacterial biofilms is of paramount importance. A pivotal stage in biofilm development is the initial bacterial attachment to these interfaces. However, the determinants of bacterial cell choice in colonizing an interface first and heterogeneity in bacterial adhesion remain elusive. Our research has unveiled variations in the buoyant density of free-swimming Staphylococcus aureus cells, irrespective of their growth phase. Cells with a low cell buoyant density, characterized by fewer cell contents, exhibited lower susceptibility to antibiotic treatments (100 μg/mL vancomycin) and favored biofilm formation at air–liquid interfaces. In contrast, cells with higher cell buoyant density, which have richer cell contents, were more vulnerable to antibiotics and predominantly formed biofilms on liquid–solid interfaces when contained upright. Cells with low cell buoyant density were not able to revert to a more antibiotic sensitive and high cell buoyant density phenotype. In essence, S. aureus cells with higher cell buoyant density may be more inclined to adhere to upright substrates.

show abstract

Section: For Any Isogenic S Aureus Population There Was a Distributio...mentioning

confidence: 99%

Role of Staphylococcus aureus’s Buoyant Density in the Development of Biofilm Associated Antibiotic Susceptibility

Kispert,

Liguori,

Velikaneye

et al. 2024

Microorganisms

View full text Add to dashboard Cite

show abstract

“…89 This would be computed as a product of the density of water, ρ w, V as the volume of volume of the particle, and g as the local acceleration due to gravity; F = ρ w × V × g; • Drag force, a viscous force described by Stokes law. 91,92 This would depend on the speed (v) and the radius of the particle (r), and the constant of viscosity (ƞ); D = 6π × ƞ × r × v; • Random forces due to the thermal fluctuation, which would augment the Brownian motion of solvent molecules. 93 These movements might, paradoxically, stabilize the MFGs; • Electrostatic forces between the charged phospholipid surface layers, the polar solvent, and other globules; 94 • van der Waals forces between the organic part of the particles.…”

Section: Biophysical Forces Acting On Mfgsmentioning

confidence: 99%

Milk Fat Globules: 2024 Updates

Bagga,

Mantry,

Maheshwari

et al. 2024

Newborn

View full text Add to dashboard Cite

Milk fat globules (MFGs) are a remarkable example of nature's ingenuity. Human milk (HM) carries contains 3-5% fat, 0.8-0.9% protein, 6.9-7.2% carbohydrate calculated as lactose, and 0.2% mineral constituents. Most of these nutrients are carried in these MFGs, which are composed of an energy-rich triacylglycerol (TAG) core surrounded by a triple membrane structure. The membrane contains polar lipids, specialized proteins, glycoproteins, and cholesterol. Each of these bioactive components serves important nutritional, immunological, neurological, and digestive functions. These MFGs are designed to release energy rapidly in the upper gastrointestinal tract and then persist for some time in the gut lumen so that the protective bioactive molecules are conveyed to the colon. These properties may shape the microbial colonization and innate immune properties of the developing gastrointestinal tract. Milk fat globules in milk from humans and ruminants may resemble in structure but there are considerable differences in size, profile, composition, and specific constituents. There are possibilities to not only enhance the nutritional composition in a goal-oriented fashion to correct specific deficiencies in the infant but also to use these fat globules as a nutraceutical in infants who require specific treatments. To mention a few, there might be possibilities in enhancing neurodevelopment, in defense against gastrointestinal and respiratory tract infections, improving insulin sensitivity, treating chronic inflammation, and altering plasma lipids. This review provides an overview of the composition, structure, and biological activities of the various components of the MFGs. We have assimilated research findings from our own laboratory with an extensive review of the literature utilizing key terms in multiple databases including PubMed, EMBASE, and Science Direct. To avoid bias in the identification of studies, keywords were short-listed a priori from anecdotal experience and PubMed's Medical Subject Heading (MeSH) thesaurus.

show abstract

“…Owing to its simplicity, ease of operation, and its low cost, the falling ball method is a well-established technique for measuring the viscosity of Newtonian fluids under ambient conditions as well as at elevated temperatures and pressures, for example, see References [6][7][8][9] for a broad spectrum of applications of the FBM. Furthermore, Brizard et al, [10,11] Sutterby [12] have discussed detailed designs, various corrections and the precision of the viscosity values for Newtonian fluids obtained by this method.…”

Section: Newtonian Fluidsmentioning

confidence: 99%

Falling ball method for determining zero shear and shear‐dependent viscosity of polymeric systems: Solutions, melts, and composites

Suri

Patel

Chhabra

2022

Vinyl Additive Technology

View full text Add to dashboard Cite

The falling ball method (FBM) is one of the well‐established techniques for measuring the viscosity of Newtonian liquids at the room as well as at elevated temperatures and pressures. Owing to its simplicity and low cost, the possibility of extending its range of application to non‐Newtonian systems including virgin and filled polymer melts, composites, polymer‐solutions, and so forth, is explored here, In this work, theoretical results for the flow of power‐law fluids past a sphere have been used to extract the values of the zero‐shear viscosity and shear‐dependent viscosity in the low‐shear rate limit. The theoretical scheme outlined here has been validated by presenting comparisons with experimental results for scores of polymer solutions for which both falling sphere and rheological data are available in the literature. Indeed, the good correspondence obtained between these two independent data is encouraging and it is thus possible to use the FBM for shear‐thinning systems when the resulting Reynolds numbers are such that the flow is viscosity‐dominated, and the inertial effects are negligible. This implies that the Reynolds number should be ≤ ~1 for shear‐thinning fluids and ≤ ~10−5 for shear‐thickening fluids.

show abstract

Stokes' law, viscometry, and the Stokes falling sphere clock

Cited by 16 publications

References 24 publications

Role of Staphylococcus aureus’s Buoyant Density in the Development of Biofilm Associated Antibiotic Susceptibility

Role of Staphylococcus aureus’s Buoyant Density in the Development of Biofilm Associated Antibiotic Susceptibility

Milk Fat Globules: 2024 Updates

Falling ball method for determining zero shear and shear‐dependent viscosity of polymeric systems: Solutions, melts, and composites

Contact Info

Product

Resources

About