-
Article
Externally driven countercurrent multiplication in a mathematical model of the urinary concentrating mechanism of the renal inner medulla
Substitution of measured permeabilities into mathematical models of the concentrating mechanism of the renal inner medulla yields less than the known urine osmolalities. To gain a better understanding of the m...
-
Chapter
Urinary Concentrating and Diluting Processes
Body fluid osmolality is normally maintained within narrow bounds through the control of body water balance. Water intake is regulated to some degree by the thirst mechanism.(1) However, the chief means by whi...
-
Chapter
Urinary Concentrating and Diluting Processes
Body fluid osmolality is normally maintained within narrow bounds through the control of body water balance. Water intake is regulated to some degree by the thirst mechanism(1) However, the chief means by which b...
-
Article
Models of coupled salt and water transport across leaky epithelia
A general formulation is presented for the verification of isotonic transport and for the assignment of a degree of osmotic coupling in any epithelial model. In particular, it is shown that the concentration o...
-
Article
A mathematical model of proximal tubule absorption
A previous model of the mechanisms of flow through epithelia was modified and extended to include hydrostatic and osmotic pressures in the cells and in the peritubular capillaries. The differential equations f...
-
Article
Transient behaviour of the single loop solute cycling model of the renal medulla
Transient solutions are developed for the buildup of a concentration gradient in the single loop solute cycling model of the renal medulla. The “pump” from ascending limb to descending limb is considered in bo...
-
Article
Analysis of the transient behavior of kidney models
Non-steady-state equations for kidney models are stated. General conservation relations for these equations are derived. Transient equations for the central core model of the renal medulla are developed. Solut...
-
Chapter
Transport Characteristics of the Loop of Henle
The loop of Henle was early identified as a structure essential for the concentration of the urine, since it occurs only in birds and mammals, the two classes that produce urine with osmolality higher than the...
-
Article
Transient behavior of the single loop solute cycling countercurrent multiplier
Transient behavior of a single loop solute cycling countercurrent multiplier is described by a Volterra type integral equation similar to that describing circulation of an indicator in the systemic circulation...
-
Article
Ability of Counterflow Systems to Concentrate
-
Article
Theory of transport in linear biological systems: II. Multiflux problems
If in a multiflux system theith flux is given by the integral equation, $$\gamma _i = \sum _j \int_0^t {w_{ij} (t - \omega )} \gamma...
-
Article
Theory of transport in linear biological systems: I. Fundamental integral equation
The conditions under which the output,γ b (t), of a biological system is related to the input,γ a ...
-
Article
Use of Katharometers in Gas Chromatography
IN a recent communication1, Ray attacks the tenet that “the use of hydrogen or helium as the carrier gas in gas Chromatography gives the highest sensitivity with a thermal conductivity detector”. He derives an eq...
-
Article
Caution in the Use of Liquid Propane for freezing Biological Specimens
ONE of the recent innovations in freezing and drying technique is the use of liquid propane for rapid freezing. This material has explosive possibilities when cooled in liquid nitrogen that many invostigators ...
-
Article
Theory for the design of apparatus for drying frozen tissues
A general theory for the design of apparatus for the low temperature drying of frozen tissues has been developed. Using this theory it is possible to compute drying rates for different materials in different a...
-
Article
Theory of the vacuum drying of frozen tissues
A general theory of the drying of frozen tissue is developed and applied to the measurement of the drying rate of frozen guinea pig liver. It is shown that for a given temperature of the subliming ice crystals...
-
Article
Theory of the measurement of blood flow by the dilution of an indicator
It is shown that the instantaneous concentration of an indicator at one point in a circulation can be related to all previous concentrations at a second point by an integral equation. Solutions of this equatio...
