Epithelial Systems Biology Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1603, USA.
Am J Physiol Renal Physiol. 2012 Aug 1;303(3):F366-72. doi: 10.1152/ajprenal.00147.2012. Epub 2012 May 30.
Concentrating models of the renal inner medulla can be classified according to external free-energy balance into passive models (positive values) and models that require an external energy source (negative values). Here we introduce an online computational tool that implements the equations of Stephenson and colleagues (Stephenson JL, Tewarson RP, Mejia R. Proc Natl Acad Sci USA 71: 1618-1622, 1974) to calculate external free-energy balance at steady state for the inner medulla (http://helixweb.nih.gov/ESBL/FreeEnergy). Here "external free-energy balance" means the sum of free-energy flows in all streams entering and leaving the inner medulla. The program first assures steady-state mass balance for all components and then tallies net external free-energy balance for the selected flow conditions. Its use is illustrated by calculating external free-energy balance for an example of the passive concentrating model taken from the original paper by Kokko and Rector (Kokko JP, Rector FC Jr. Kidney Int 2: 214-223, 1972).
根据外部自由能平衡，肾髓质浓缩模型可分为被动模型（正值）和需要外部能源的模型（负值）。这里我们引入一个在线计算工具，它实现了 Stephenson 及其同事的方程（Stephenson JL，Tewarson RP，Mejia R. Proc Natl Acad Sci USA 71: 1618-1622, 1974），用于计算肾髓质在稳态下的外部自由能平衡（http://helixweb.nih.gov/ESBL/FreeEnergy）。这里的“外部自由能平衡”是指进入和离开肾髓质的所有流的自由能流的总和。该程序首先确保所有成分的稳态质量平衡，然后为所选流动条件计算净外部自由能平衡。通过计算 Kokko 和 Rector（Kokko JP，Rector FC Jr. Kidney Int 2: 214-223, 1972）原始论文中被动浓缩模型的一个例子的外部自由能平衡来说明其用法。
