scholarly journals Alveolar liquid lining: Langmuir method used to measure surface tension in bovine and canine lung extracts.

1985 ◽  
Vol 359 (1) ◽  
pp. 65-79 ◽  
Author(s):  
B A Hills
Keyword(s):  
Surface Tension ◽  
Langmuir Method ◽  
Alveolar Liquid

scholarly journals Surface tension in situ in flooded alveolus unaltered by albumin

2014 ◽  
Vol 117 (5) ◽  
pp. 440-451 ◽  
Author(s):  
Angana Banerjee Kharge ◽  
You Wu ◽  
Carrie E. Perlman
Keyword(s):  
Surface Tension ◽  
Plasma Proteins ◽  
Lung Surfactant ◽  
Exogenous Surfactant ◽  
Surfactant Activity ◽  
Interfacial Surfactant ◽  
Isolated Rat Lung ◽  
Alveolar Liquid

In the acute respiratory distress syndrome, plasma proteins in alveolar edema liquid are thought to inactivate lung surfactant and raise surface tension, T. However, plasma protein-surfactant interaction has been assessed only in vitro, during unphysiologically large surface area compression (%Δ A). Here, we investigate whether plasma proteins raise T in situ in the isolated rat lung under physiologic conditions. We flood alveoli with liquid that omits/includes plasma proteins. We ventilate the lung between transpulmonary pressures of 5 and 15 cmH2O to apply a near-maximal physiologic %Δ A, comparable to that of severe mechanical ventilation, or between 1 and 30 cmH2O, to apply a supraphysiologic %Δ A. We pause ventilation for 20 min and determine T at the meniscus that is present at the flooded alveolar mouth. We determine alveolar air pressure at the trachea, alveolar liquid phase pressure by servo-nulling pressure measurement, and meniscus radius by confocal microscopy, and we calculate T according to the Laplace relation. Over 60 ventilation cycles, application of maximal physiologic %Δ A to alveoli flooded with 4.6% albumin solution does not alter T; supraphysiologic %Δ A raise T, transiently, by 51 ± 4%. In separate experiments, we find that addition of exogenous surfactant to the alveolar liquid can, with two cycles of maximal physiologic %Δ A, reduce T by 29 ± 11% despite the presence of albumin. We interpret that supraphysiologic %Δ A likely collapses the interfacial surfactant monolayer, allowing albumin to raise T. With maximal physiologic %Δ A, the monolayer likely remains intact such that albumin, blocked from the interface, cannot interfere with native or exogenous surfactant activity.

scholarly journals Tracheal acid or surfactant instillation raises alveolar surface tension

2018 ◽  
Vol 125 (5) ◽  
pp. 1357-1367 ◽  
Author(s):  
Tam L. Nguyen ◽  
Carrie E. Perlman
Keyword(s):  
Surface Tension ◽  
Distress Syndrome ◽  
Exogenous Surfactant ◽  
Acid Aspiration ◽  
Isolated Lungs ◽  
Lavage Solution ◽  
Alveolar Surface ◽  
Normal Lungs ◽  
Alveolar Liquid

Whether alveolar liquid surface tension, T, is elevated in the acute respiratory distress syndrome (ARDS) has not been demonstrated in situ in the lungs. Neither is it known how exogenous surfactant, which has failed to treat ARDS, affects in situ T. We aim to determine T in an acid-aspiration ARDS model before and after exogenous surfactant administration. In isolated rat lungs, we combine servo-nulling pressure measurement and confocal microscopy to determine alveolar liquid T according to the Laplace relation. Administering 0.01 N (pH 1.9) HCl solution by alveolar injection or tracheal instillation, to model gastric liquid aspiration, raises T. Subsequent surfactant administration fails to normalize T. Furthermore, in normal lungs, tracheal instillation of control saline or exogenous surfactant raises T. Lavaging the trachea with saline and injecting the lavage solution into the alveolus raises T, suggesting that tracheal instillation may wash T-raising airway contents to the alveolus. Adding 0.01 N HCl or 5 mM CaCl2—either of which aggregates mucins—to tracheal lavage solution reduces or eliminates the effect of lavage solution on alveolar T. Following tracheal saline instillation, liquid suctioned directly out of alveoli through a micropipette contains mucins. Additionally, alveolar injection of gastric mucin solution raises T. We conclude that 1) tracheal liquid instillation likely washes T-raising mucins to the alveolus and 2) even exogenous surfactant that could be delivered mucin-free to the alveolus might not normalize T in acid-aspiration ARDS. NEW & NOTEWORTHY We demonstrate in situ in isolated lungs that surface tension is elevated in an acid-aspiration acute respiratory distress syndrome (ARDS) model. Following tracheal liquid instillation, also in isolated lungs, we directly sample alveolar liquid. We find that liquid instillation into normal lungs washes mucins to the alveolus, thereby raising alveolar surface tension. Furthermore, even if exogenous surfactant could be delivered mucin-free to the alveolus, exogenous surfactant might fail to normalize alveolar surface tension in acid-aspiration ARDS.

scholarly journals Phosphatidylcholine — Mg2+ equilibria in a monolayer at the air/water interface

2013 ◽  
Vol 11 (3) ◽  
pp. 424-429 ◽  
Author(s):  
Aneta Petelska ◽  
Zbigniew Figaszewski
Keyword(s):  
Surface Tension ◽  
Stability Constants ◽  
Equilibrium Theory ◽  
Water Interface ◽  
Free Energies ◽  
Air Water Interface ◽  
The Stability ◽  
Langmuir Method

AbstractAbstract The interaction between Mg2+ and a phosphatidylcholine (lecithin, L) monolayer at the air/water interface was investigated. Surface tension measurements (Langmuir method) of phosphatidylcholine monolayers as a function of Mg2+ concentration were carried out at 22°C using a Teflon trough and a Nima 9000 tensiometer. Interactions between phosphatidylcholine and Mg2+ result in significant deviations from additivity. An equilibrium theory was developed to obtain the stability constants and areas occupied by one molecule of LMg+ and L2Mg. The stability constants were K 1 = 9.95×102 m2 mol−1 and K 2 = 3.87×104 m2 mol−1. The area occupied by LMg+ is 77 Å2 molecule−1, while that occupied by L2Mg is 109 Å2 molecule−1. The Gibbs free energies of complexation for LMg+ and L2Mg are −16.91 ± 0.51 and −25.88 ± 0.76 kJ mol−1. Graphical abstract

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

The Use of Styrenes as Embedding Media for Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 488-489
Author(s):  
Edward D. De-Lamater ◽  
Eric Johnson ◽  
Thad Schoen ◽  
Cecil Whitaker
Keyword(s):  
Electron Microscopy ◽  
Surface Tension ◽  
Ultraviolet Light ◽  
Methyl Ethyl Ketone Peroxide ◽  
Methyl Ethyl ◽  
Styrene Polymerization ◽  
Radical Initiation ◽  
Tertiary Butyl ◽  
Low Viscosity ◽  
Free Radical Initiation

Monomeric styrenes are demonstrated as excellent embedding media for electron microscopy. Monomeric styrene has extremely low viscosity and low surface tension (less than 1) affording extremely rapid penetration into the specimen. Spurr's Medium based on ERL-4206 (J.Ultra. Research 26, 31-43, 1969) is viscous, requiring gradual infiltration with increasing concentrations. Styrenes are soluble in alcohol and acetone thus fitting well into the usual dehydration procedures. Infiltration with styrene may be done directly following complete dehydration without dilution.Monomeric styrenes are usually inhibited from polymerization by a catechol, in this case, tertiary butyl catechol. Styrene polymerization is activated by Methyl Ethyl Ketone peroxide, a liquid, and probably acts by overcoming the inhibition of the catechol, acting as a source of free radical initiation.Polymerization is carried out either by a temperature of 60°C. or under ultraviolet light with wave lengths of 3400-4000 Engstroms; polymerization stops on removal from the ultraviolet light or heat and is therefore controlled by the length of exposure.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

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