Concentration bicarbonate

Increasing concentrations of bicarbonate tended to raise the breakdown potentials but also increased the corrosion potentials. This, in combination with a high chloride concentration, high bicarbonate concentrations may raise the corrosion potentials such that they border on passivation breakdown. The increase in hysteresis loop size on potentiodynamic cycles with increasing bicarbonate concentration shows a lowered resistance to pitting attack and crevice corrosion. 

The existence of such a process can be indirectly evidenced by the irregular change of decrement observed in free carbonate (also bicarbonate) concentrations near pH = 10 as illustrated in Figure 3. This may be ascribed to the consumption of free carbonate ions for the formation of the plutonium hydroxocarbonate precipitate. The reactions involved in this process are interpreted as follows ... 

Sahlin, K., Alvestrand, A., Brandt, R., Hultman, E. (1978). Intracellular pH and bicarbonate concentration in human muscle during recovery from exercise. J. Appl. Physiol. 45,474—480. 

Despite increased citrate accumulation in roots of Zn-deficient rice plants, root exudation of citrate was not enhanced. However, in distinct adapted rice cultivars, enhanced release of citrate could be observed in the presence of high bicarbonate concentrations in the rooting medium, a stress factor, which is frequently associated with Fe and Zn deficiency in calcareous soils (235) (Hajibo-huid, unpublished). This bicarbonate-induced citrate exudation has been related to improved Zn acquisition in bicarbonate-tolerant and Zn-efficient rice genotypes (Fig. 9) (23S). Increased exudation of sugars, amino acids, and phenolic compounds in response to Zn deficiency has been reported for various dicotyledonous and monocotyledonous plant species and seems to be related to increased... 

Electrolytes Daily doses based on daily maintenance requirements, renal function, gastrointestinal losses, acid-base status, concomitant drug therapy, nutritional and anabolic status Pa lion I has hyponatremia, hypokalemia, hypomagnesemia, and hypophosphatemia, also has low serum bicarbonate concentration, could be component of metabolic acidosis due to sepsis... 

The kidney exerts control over the concentration of bicarbonate. The initial filtrate of the kidney has the same buffer composition (except for the proteins) as serum. Based on the pH of the initial filtrate, the kidney can decide to reclaim the initially filtered bicarbonate and place it back in the serum, or it can decide to just let it go out of the body. If the kidney does not reclaim bicarbonate, the serum bicarbonate concentration falls. If the kidney reclaims more bicarbonate than normal, the bicarbonate concentration rises. 

Figure 6-6 also shows the variation in the partial pressure of carbon dioxide in equilibrium with the lagoon s waters. The average value of this pressure exceeds the atmospheric value, 1, so on average, carbon dioxide is evaporating from the lagoon. The evaporation rate is greatest at times of maximum alkalinity and bicarbonate concentration and minimum carbonate ion concentration. 

Figure 6-8 shows how the partial pressure of carbon dioxide in equilibrium with surface water oscillates in phase with the fluctuations in precipitation rate, saturation state, and temperature. The oscillations in alkalinity and bicarbonate concentrations have shifted in phase by about 90° because these quantities decrease when precipitation and evaporation are removing carbon from the system at above-average rates. 

Metabolic acidosis is characterized by decreased plasma bicarbonate concentrations (HC03 ), whereas metabolic alkalosis is characterized by increased HC03T... 

Overall, for each bicarbonate ion filtered, one has been returned to the blood that is sodium bicarbonate has been reabsorbed and the glomerular filtrate leaving the PCT has a greatly reduced bicarbonate concentration. The relatively small amount of proton secreted by the PCT cell and not used to protonate filtered bicarbonate... 

Bicarbonate ions secreted into the blood stream help maintain the normal plasma bicarbonate concentration of approximately 25 mmol/1, whilst the two protons are secreted into the lumen of the proximal tubule in exchange for sodium via a Na+/H+ antiport. 

These results suggest acute renal failure (ARF) due to tubular necrosis caused by phenol. Plasma sodium is low due mainly to impaired reabsorption in the nephron, although the slightly low albumin suggests haemodilution possibly as a result of excessive i.v. fluids. Potassium is raised due to poor exchange with sodium in the distal tubule and the acidosis (low pH and low bicarbonate concentration) arises from defective acidification of the glomerular filtrate acidosis is often associated with hyperkalaemia (raised plasma... 

There are several interesting aspects to this study. The dependence on bicarbonate concentration can be described formally by introducing Equation 11.42 into Equation 11.41 and assuming that only the reaction specified by rate constant k5 is isotope sensitive ... 

Bardow A, Madsen J, Bauntofte B (2000) The bicarbonate concentration in human saliva does not exceed the plasma level under normal physiological conditions. Clin Oral Invest 4 245-253... 

LeBoeuf, R.A., and Kerckaert, G., Enhanced morphological transformation of early passage Syrian hamster embryo cells cultured in medium with a reduced bicarbonate concentration and pH, Carcinogenesis, 8, 680, 1987. 

Equations (17) and (18) allow one to link respectively (i) the dissolved CO2 concentration with the gas composition and the gas flow rate and (ii) the bicarbonate concentration with the gas composition, the gas flow rate and the pH. The estimated value can be then compared to the measured one to build a belief assignment with the same methodology and parameters than in the case of the strict physical redundancy. 

Distilled water, which equilibrates with CO2 of a non-polluted atmosphere, has a pH of 5.65. At this pH, proton and bicarbonate concentrations are equal and alkalinity becomes zero [9]. We consider freshwaters acidic when [Alk]<0 meq 1 ... 

Calculating the bicarbonate concentrations with (3), it is possible to plot the measured average pH values of Table 2 against the calculated loglHCOs ]. The result is shown in Fig. 5a. For pH >5.5 a linear relationship, very close to that reported in the literature, can be observed (pH = loglHCOa ] + 11.2). However, for acid lakes the calculated bicarbonate concentrations seem to be too low. It is reported that at pH<6 the release of metals from soils or sediments as a consequence of weathering processes becomes more and more important. Consequently aluminium hydroxides can influence alkalinity. In [18] the equation for calculating alkalinity was modified as follows ... 

In Fig. 5b the calculated bicarbonate concentrations of the three lakes with the lowest pH were corrected considering the dissolved aluminium concentrations... 

If heparin comprises 10% or more of the total volume of a sample for blood gas analysis, errors in measurements of carbon dioxide pressure, bicarbonate concentration, and base excess may occur. 

It can be seen that chloride, sulfate and bicarbonate concentrations are higher in the sample from Viriato station, because here the atmosphere is more contaminated. Nevertheless, the relation between the chloride concentration in the corrosion products from Viriato and Quivican is (24.64/15 = 1.65) far smaller than the Cl-DR relation (495.68/3.9 =... 

For patients who have ingested more than 30 ml of (pure) methanol or ethylene glycol, dialysis is recommended, and haemodialysis is more effective than peritoneal dialysis. Dialysis both removes the alcohols and their metabolites, and corrects the renal and metabolic disturbances and so is the preferred treatment in severe poisoning. The maintenance dose of ethanol required may be tripled during haemodialysis as ethanol is also removed. Early treatment is indicated if ethylene glycol concentrations are above 20 mg/100 ml (200 mg/1), if the arterial pH is below 7.3, if serum bicarbonate concentrations are less than 20 mM/1, and when there are oxalate crystals in the urine. 

To determine if bicarbonate has similar effects on the nature of the radiocolloid, the plutonium size distributions were studied at pH 7 as a function of bicarbonate concentration, using bicarbonate only from atmospheric CO.j and in solutions with [CH(V] equal to 10"2Af. The latter were prepared by adding NaHCOa. Two different ionic strengths were used to distinguish between the effects of added bicarbonate and ionic strength. The distributions of identical solutions which were shaken in flasks with and without granular silica were determined initially and... 

Figure 3. Relation between ammonium bicarbonate concentration in effluent and feed composition...

An 82-year-old man and a 76-year-old man with normal renal function developed increased lactate concentrations (3.6 mmol/1 and 3.2 mmol/1 respectively) a few weeks after starting to take metformin (54). Both had a low bicarbonate concentration and high anion gap. The second patient was also taking ciprofloxacin for a urinary tract infection. In both patients lactate reached normal values after metformin was withdrawn. 

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