Measurements of the Surface Diffusion Coefficient in Iron-Carbon Alloys Using Focused Ion Beam Milling and High Temperature Laser Scanning Confocal Microscopy

Abstract Our early studies showed that tissue diffusion coefficient (Dt) of small solute sodium fluorescein (0.45 nm radius) in frog mesentery is 30% of its free diffusion coefficient (Dfree) in aqueous solution. We test here the hypothesis that because of its size-limiting structure the interstitium would provide larger resistance to larger solute α-lactalbumin (2.0 nm radius). We extended our previous method by using laser-scanning confocal microscopy to measure both solute capillary permeability (P) and solute tissue diffusion coefficients (Dt) from the rate of tissue solute accumulation and the radial concentration gradients around individually perfused microvessels in frog mesentery. pα-lactalbumin was 1.7 ± 0.7 (SD) × 10−6 cm/s (n = 6). Dt/Dfree was 27% ± 5% (SD) (n = 6). This value is comparable to that for small solute sodium fluorescein. Our results indicate that frog mesenteric interstitium is less selective to larger solute α-lactalbumin than the microvessel wall.

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Concentric Solidification for High Temperature Laser Scanning Confocal Microscopy

ISIJ International ◽

10.2355/isijinternational.44.565 ◽

2004 ◽

Vol 44 (3) ◽

pp. 565-572 ◽

Cited By ~ 51

Author(s):

Mark Reid ◽

Dominic Phelan ◽

Rian Dippenaar

Keyword(s):

High Temperature ◽

Confocal Microscopy ◽

Laser Scanning ◽

Laser Scanning Confocal Microscopy ◽

Scanning Confocal Microscopy

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Determination of Microvessel Permeability and Tissue Diffusion Coefficient of Solutes by Laser Scanning Confocal Microscopy

Journal of Biomechanical Engineering ◽

10.1115/1.1865186 ◽

2004 ◽

Vol 127 (2) ◽

pp. 270-278 ◽

Cited By ~ 16

Author(s):

Bingmei M. Fu ◽

Roger H. Adamson ◽

Fitz-Roy E. Curry

Keyword(s):

Diffusion Coefficient ◽

Confocal Microscopy ◽

Laser Scanning ◽

Laser Scanning Confocal Microscopy ◽

Sodium Fluorescein ◽

Solute Permeability ◽

Scanning Confocal Microscopy ◽

Stokes Radius ◽

Microvessel Wall ◽

Tissue Diffusion

Interstitium contains a matrix of fibrous molecules that creates considerable resistance to water and solutes in series with the microvessel wall. On the basis of our preliminary studies (Adamson et al., 1994, Microcirculation 1(4), pp. 251–265; Fu et al., 1995 Am. J. Physiol. 269(38), pp. H2124–H2140), by using laser-scanning confocal microscopy and a theoretical model for interstitial transport, we determined both microvessel solute permeability (P) and solute tissue diffusion coefficient (Dt) of α-lactalbumin (Stokes radius 2.01nm) from the rate of tissue solute accumulation and the radial concentration gradient around individually perfused microvessel in frog mesentery. Pα‐lactalbumin is 1.7±0.7(SD)×10−6cm∕s(n=6). Dt∕Dfree for α-lactalbumin is 27%±5%(SD)(n=6). This value of Dt∕Dfree is comparable to that for small solute sodium fluorescein (Stokes radius 0.45nm), while Pα‐lactalbumin is only 3.4% of Psodiumfluorescein. Our results suggest that frog mesenteric tissue is much less selective to solutes than the microvessel wall.

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