Water movement occurs to a variable degree across every epithelial layer of cells and plays a determinant role in the homeostasis of body fluid balance. Is such water transport the result of a difference of water activity or osmotic pressure across the epithelium? The answer to that question is more often negative as demonstrated by the phenomenon of isotonic water movement. Many epithelia tran...

Numerical simulations of water ̄ow and solute transport were used to investigate the e€ect of the recharge (rain/irrigation) at the soil surface on solute spreading and breakthrough in a realistic, three-dimensional, heterogeneous, vadose zone±groundwater ̄ow system. Results of the analyses suggest that smaller recharge at the soil surface increases the relative variability in the response of t...

Successful prediction of groundwater flow and solute transport through highly heterogeneous aquifers has remained elusive due to the limitations of methods to characterize hydraulic conductivity (K) and generate realistic stochastic fields from such data. As a result, many studies have suggested that the classical advective-dispersive equation (ADE) cannot reproduce such transport behavior. Her...

Horizontal contaminant transport through unsaturated soil been demonstrated both analytically and experimentally. The water and solute transport equations were solved using the Boltzman transformation, to convert the partial differential equations to ordinary differential equations. The resulted mathematical model was verified using experimental data. A laboratory scale column system was constr...

Surface-applied chemicals move through the unsaturated zone with complex flow and transport processes due to soil heterogeneity and reach the saturated zone, resulting in groundwater contamination. Such complex processes need to be studied by advanced measurement and modeling techniques to protect soil and water resources from contamination. In this study, the interactive effects of factors lik...

We investigated effects of acute hyperoxia on solute transport from air space to vascular space in isolated rat lungs. Air spaces were filled with Krebs-Ringer bicarbonate solution containing fluorescein isothiocyanate-labeled dextran (FD-20; mol wt 20,000) and either 22Na+ and [14C]sucrose, or D-[14C]glucose and L-[3H]glucose. Apparent permeability-surface area products for tracers over time (...

We demonstrate noninvasive quantitative imaging of colloid and solute transport at millimeter to decimeter (meso-) scale. Ultraviolet (UV) excited fluorescent solute and colloid tracers were independently measured simultaneously during co-advection through saturated quartz sand. Pulse-input experiments were conducted at constant flow rates and ionic strengths 10(-3), 10(-2) and 10(-1) M NaCl. T...

Data truncation is a practical necessity of laboratory column experiments because of both time and detection-limit constraints. In this paper, we study the extent to which data truncation can a€ect estimates of transport modeling parameters, as derived from temporal moment calculations and in the context of solute transport experiments that are in ̄uenced by sorption and nonequilibrium partition...