Some physiological and physical aspects of the surface tension of urine

Abstract

A STUDY is being carried out of the surface phenomena of the complex colloidal systems occurring in the body. Among these urine has been investigated and found of such interest and importance that a thorough investigation was made. In the following paper the results of the work on surface tension are recorded.Little work has hitherto been attempted in this field, and the literature is both scanty and often contradictory. Several reasons may be adduced to explain these discrepancies. The variation of the methods employed and the frequent use of artificial standards have entailed confusion, and further, most of the work has been done with the object of finding diagnostic applications before the normal physiological variations and physical aspects of the problem had been studied [Bechold and Reiner, 1920;Schemensky, 1920].For this reason we have, here, mainly recorded the result of the work done in investigating the surface tension of normal urine under varying conditions both physiological and physical. The results show that the colloidal system of this excretion is a complex and interesting one and that further work on its physical properties, conditions, and equilibrium may well throw light on such controversial problems as the formation of calculi, hormonic secretion and possibly liver function. METHODS.For determining surface tension (S.T.) several methods are available, but when due regard is paid to limitations, accuracy, speed, reliability and applicability to this field, it is found that many are unsuited to the routine examination of biological liquids.

A study on the method of Taila Bindu Pariksha (oil drop test)

“…Immediately after voiding, value of surface tension of urine was maximum which decreased with time. [6] This might be the reason of slow spread in the starting. Later on, changes occur due to bacterial decomposition of urine constituents, so spread occurs faster.…”

Capillary driven low-cost V-groove microfluidic device with high sample transport efficiency

“…15 In order to use open V-grooves as liquid transport channels in microfluidic sensors, it is necessary to understand the wicking dynamics of liquids of much higher g/h ratio. This is because most diluted aqueous indicator solutions and some human samples, such as urine sample, 17 have relatively high g/h ratios in the range of 5600-7300 cm/s (with that of water being 7300 cm/s). Samples in open capillaries are prone to evaporation loss, therefore, transport speed must be high enough so as to minimize such loss.…”

Single-Droplet Multiplex Bioassay on a Robust and Stretchable Extreme Wetting Substrate through Vacuum-Based Droplet Manipulation

“…The droplets with varying surface tensions were prepared by mixing water, which has a high surface tension (72 mN/m) and ethanol, which has a low surface tension (21.8 mN/m) with different mixing ratios. The SPO PDMS substrate showed extreme repellency toward the liquid droplets with a surface tension greater than 33 mN/m, which is lower than that of most biological fluids, such as blood, plasma, sweat, and urine (46–72 mN/m). − The extreme wettability of the SPO/SPI PDMS substrate can be explained by the low surface energy of the hierarchical micro- and nanostructures. Figure d shows a schematic of wettability principles for the hierarchically structured SPO/SPI layers.…”