Mineral ions

Mixing time Mineral ions Activities of whole cells... 

NOTE In practice, higher quality, pre-boiler water treatment generally means the use ofFW with significantly lower levels of dissolved solids than typically employed in lower rated boilers. Additionally, it implies the reduction of certain specific minerals, ions, and noncondensable gases to meet very low, or extremely low, concentration specifications. 

Electrostatic devices These devices provide a static field within the water via the production of a very high localized voltage (but low current). It is claimed that this field physically affects the dissolved mineral ions and inhibits the precipitation of scale. 

Allelopathic inhibition of mineral uptake results from alteration of cellular membrane functions in plant roots. Evidence that allelochemicals alter mineral absorption comes from studies showing changes in mineral concentration in plants that were grown in association with other plants, with debris from other plants, with leachates from other plants, or with specific allelochemicals. More conclusive experiments have shown that specific allelochemicals (phenolic acids and flavonoids) inhibit mineral absorption by excised plant roots. The physiological mechanism of action of these allelochemicals involves the disruption of normal membrane functions in plant cells. These allelochemicals can depolarize the electrical potential difference across membranes, a primary driving force for active absorption of mineral ions. Allelochemicals can also decrease the ATP content of cells by inhibiting electron transport and oxidative phosphorylation, which are two functions of mitochondrial membranes. In addition, allelochemicals can alter the permeability of membranes to mineral ions. Thus, lipophilic allelochemicals can alter mineral absorption by several mechanisms as the chemicals partition into or move through cellular membranes. Which mechanism predominates may depend upon the particular allelochemical, its concentration, and environmental conditions (especially pH). 

A third possibility is that mineral ions leak out of tissue in the presence of phenolic acids, not because membrane permeability is altered, but rather because the driving force that maintains high ion concentrations in cells (i.e. PD) is dissipated by the chemicals. Without an electrical potential, ions would distribute solely according to their chemical concentrations. Thus, most ions would leak out of cells to reach chemical equilibrium with the external environment. 

Although several allelochemicals (primarily phenolic acids and flavonoids) have been shown to inhibit mineral absorption, only the phenolic acids have been studied at the physiological and biochemical levels to attempt to determine if mineral transport across cellular membranes can be affected directly rather than indirectly. Similar and even more definitive experiments need to be conducted with other allelochemicals that are suspected of inhibiting mineral absorption. Membrane vesicles isolated from plant cells are now being used to elucidate the mechanism of mineral transport across the plasma membrane and tonoplast (67, 68). Such vesicle systems actively transport mineral ions and thus can serve as simplified systems to directly test the ability of allelochemicals to inhibit mineral absorption by plant cells. 

To complete the deionization process, water from the cation unit is passed through a strong base anion exchange resin in the hydroxide form. The resin exchanges hydrogen ions for both highly ionized mineral ions and the more weakly ionized carbonic and silicic acids according to1,2 ... 

Taiz and Zeiger (2002) give a full account of this topic. Mineral ions absorbed from solution outside the root surface must be transported across the root to the main long-distance transport vessels in the xylem, through which they reach the shoot. This process is highly specific for different ions and molecules and is closely regulated. The regulation is in part a fnnction of the anatomy of the varions root tissues and in part a fnnction of active transport processes in root cells. The pathways and transport processes are affected by root adaptations to anoxia. 

Chattopadhyay, N., Mithal, A., and Brown, E. M. (1996) The calcium-sensing receptor a window into the physiology and pathophysiology of mineral ion metabolism. Endocr. Rev. 17, 289-307. 

The problematic agent in this list are builders, compounds that sequester ("capture") mineral ions such as calcium and magnesium that would otherwise reduce the sudsing properties of a cleaning agent. One of the most effective builders ever discovered, and one that was widely used for many years, is sodium tripolyphosphate (TPP). The structure of this molecule is such that it can surround and trap ions (such as Ga "" and Mg "") that are responsible for the "hardness in water (which reduces the effectiveness of a detergent). 

The elementary unit cell can be quite easily described starting from the four mineral ion sites of the crystal F, Ca f+, Ca(ll)2+ and P04 , where the symbols I and II represent the two different crystallographic sites of the cations, with the application of all the symmetry operations relevant to the space group P63/m. Among the principal symmetry elements, one can cite mirror planes perpendicular to the c-axis (at z = 1/4 and 3/4), which contain most of the ions of the structure (F , Ca +(ll), P04 ), three-fold axes parallel to the c-axis (at x = 1/3, y = 2/3 and x = 2/3, y = 1/3) along which are located the Ca + (I) ions, screw axes 63 at the corners of the unit cell and parallel to the c-axis and screw axes 2i parallel to the c-axis and located at the midpoints of the cell edges and at the centre of the unit cell itself [3]. 

Fig. 8. Evolution of synthetic and biological apatites in the presence of fluoride ions. The increase of pH and/or phosphate concentration in solution favours the formation of fluoridated apatite, whereas the increase of fluoride and/or calcium concentration favours CaF2 formation. At physiologic pH and mineral ions concentrations (in all body fluids), the formation of fluoridated apatite is favoured.

It appears to be the case that most animals maintain the concentration of mineral ions at constant levels in their extracellular fluids. Perturbations with various forms of acidosis usually result in the animal re-establishing an equilibrium between its body fluids and the apparent solubility product of some mineral. Two important conclusions follow from this. First, it provides a theoretical basis for defining calcification. When there is a change of phase in the total extracellular fluids (i. e., mineralization occurs) then the fluids re-equilibrate to make good the ions which have been lost as minerals. 

No final comprehensive hypothesis of the chain of events in biological calcification processes can be constructed at the present time. All current major theories on the sequence of events — leading to translocation of mineral ions into initial mineral phase — involve overcoming the energy of activation required for forming the first primitive stable mineral clusters. Then calcium and phosphate are present at levels... 

The migration time of mineral ions depends on the limit of their equivalent conductivity. 

Salt. When compared on a molar basis, the mineral ion salts (ammonium, calcium, rubidium, copper, silver, lead, manganese, cobalt, potassium, and sodium, and cyclohexylamine salt) were as effective as the free gibberellic acid in promoting stem elongation (10,14). As shown in Figure 1, the potassium and zinc salts of A3 were as active as the acid in promoting the growth of d-1 dwarf maize. 

With regard to complex formation, tetracyclines and cholestyramine are common examples—although their mechanisms are different. In the case of tetracyclines, complexes of the antibiotic can be formed with a number of positive, polyvalent mineral ions such as Al3+, Ca2+, and Mg2+. Such minerals are commonly present in antacids and milk. The result of such complex formation is diminished absorption of tetracycline. This is the reason why patients taking tetracyclines are directed to avoid taking milk with their medication. 

Study of the potassium ion has been neglected [41] compared with other mineral ions like Cu2+ [42, 43], although it plays important biochemical and biophysical roles in plant cells. K+ serves as a major contributor to osmotic poten-... 

Therefore, oxidation-reduction processes in nature control the behavior of elements or substances. During oxidation-reduction, the potential for reactions to take effect changes because the redox status of elements changes. A summary of soil-water mineral-ion properties known to be affected by redox chemistry is listed below ... 

Whereas the ion-exchange affinity of various mineral ions to ion exchangers is reasonably well understood, the ion-exchange affinity of various amino acid ions is not because of their more complex nature. 

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