Function filtration

Certain antibiotics such as the tetracyclines, streptomycin, neomycin and kanamycin can cripple the tubules if taken in excessive amounts. Toxic damage to the kidneys can affect not only their filtration functions, but can alter the organs control over blood levels of certain critical molecules. A complex biochemical-hormonal system controlling blood pressure and volume, for example, is regulated by the kidneys, so that chronic kidney damage can inflict damage on the... 

In addition to their filtration function, the kidneys are also metabolically active and carry out extensive oxidation, reduction, hydrolysis, and conjugation reactions, with enzymes similar to those present in the liver and other extrarenal tissues involved in these metabolic reactions, f0 As noted previously, metabolites of xenobiotics are often toxic than the parent compounds. As a result of the combination of the filtration and metabolic functions, the kidneys are targets for many toxic chemicals. 

Given the almost constant exposure of humans to toxic chemicals (via air pollution, water pollution, or food contamination) and the filtration function of the kidneys, one could easily argue that the kidneys are almost constantly exposed to mixtures of toxic chemicals and that the uptake of additional xenobiotic chemicals creates new mixtures. As we have already seen earlier, many single chemicals have been shown to be renal toxins. Whether the observed nephrotoxic effects of any of these chemicals are because of its interactions with endogenous or other exogenous chemicals is unknown. What is known is that exposures to some chemical mixtures are toxic to the kidneys of test animals and humans. Examples of studies demonstrating mixture effects follow ... 

Filters have been extensively used in households and industry for removing particles from air or liquid. In the case of enviromental protection filters are used to remove pollutants from air or water. In military, filters are used in uniform garments and isolating bags to decontaminate aerosol dusts, bacteria, while maintaining permeability to moisture vapor for comfort. A respirator is another example requiring an efficient filtration function. The same properties are also needed for some fabrics used in the medical field. ... 

Recently, the measnrement of FITC-sinistrin using the transcutaneous device (optical GFR) was directly compared with simultaneous GFR measurements obtained from gadolinium-based contrast agent filtration in the MRI (MRI-GFR ZoUner et al., 2013). While discrepancies between the two detection methods were observed, the study demonstrated that MRI-GFR, similarly to optical GFR, allowed for visualization of the filtration function in healthy and unilateral nephrectomy rats (Zollner et al., 2013). 

Yu W, Sandoval RM, and BA Mofitoris (2007). Rapid determination of renal filtration function nsing an optical ratiometric imaging approach. American Journal of Physiology. Renal Physiology 292 F1873-F1880. 

Filtration function (a) Without geotextile and (b)With geotextile. 

Similar to the filtration function, the requirements for drainage are soil retention, adequate flow capacity, and long term soil-to-geotextile flow equilibrium, in respect of minimum clogging of the pore spaces. Apart from the flow capacity within the plane of the geosynthetic material, the other aspects have been dealt with above. We will therefore now consider the inplane flow characteristics. 

The soil retention function of the geotextile separator can be seen as similar to the geotextile filter, in that for a suitable separator the AOS of the geotextile must be related to the particle size distribution and, as stated under the filtration function, this aspect will be considered in more detail later when describing the relationship between structure, properties, and functionalities of geotextiles. 

It has to be stressed that geotextiles cannot always replace the granular filter completely (see Sec. 19.2.3). A granular layer can often be needed to reduce (damp) the hydraulic loadings (internal gradients) to an acceptable level at the soil interface. After that, a geotextile can be applied to fulfill the filtration function. 

According to the filtration function, a geotextile filter must be able to retain fine particles of base soil (retention criterion) and avoid the development of excessive pore water pressure on a soil geotextile interface (ie, fi ee flow of liquid through the geotextile plane) (permeabihty criterion). 

Finally, the geotextile must have the required filtration/hydraulic characteristics to provide the coincident functions of separation, filtration, and drainage. Properties required for separation and filtration functions are related to opening characteristics... 

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