Fluctuations in the concentration

The liver is involved in the metabolism of practically all groups of metabolites. Its functions primarily serve to cushion fluctuations in the concentration of these substances in the blood, in order to ensure a constant supply to the peripheral tissues (homeostasis). 

A chemical relaxation technique that measures the magnitude and time dependence of fluctuations in the concentrations of reactants. If a system is at thermodynamic equilibrium, individual reactant and product molecules within a volume element will undergo excursions from the homogeneous concentration behavior expected on the basis of exactly matching forward and reverse reaction rates. The magnitudes of such excursions, their frequency of occurrence, and the rates of their dissipation are rich sources of dynamic information on the underlying chemical and physical processes. The experimental techniques and theory used in concentration correlation analysis provide rate constants, molecular transport coefficients, and equilibrium constants. Magde" has provided a particularly lucid description of concentration correlation analysis. See Correlation Function... 

A fluctuation in the concentration of a small volume element 5 V of solution will result in a change in the properties of that volume element. We begin the analysis of this situation by defining 8c and 8a as the fluctuations in solution concentration and polarizability, respectively, in this element. The first thing that we recognize about these quantities is that their average values are zero since both positive and negative fluctuations occur. 

Figure 2. Periodicity of Asterionella formosa Hass., Fragilaria Crotonensis and fluctuations in the concentration of dissolved silica, in 0—5-meter water...

Multivariate statistical methods should be preferred for evaluating such multidimensional data sets since interactions and resulting correlations between the water compounds have to be considered. Fig. 8-1, which shows the univariate fluctuations in the concentrations of the analyzed compounds, illustrates the large temporal and local variability. Therefore in univariate terms objective assessment of the state of pollutant loading is hardly possible. 

Given that 3a,5a-THP positively modulates GABAa-Rs (Belelli and Lambert, 2005 Majewska, 1992), subsequent studies have been undertaken to determine whether the physiological fluctuations in the concentrations of these neuroactive steroids that occur during pregnancy and after delivery may also affect the gene expression of different subunits of both synaptic and extrasynaptic GABAa-Rs in the rat brain. 

The excess entropy production due to a fluctuation in the concentration of X around a steady-state value is... 

Let us look at how the rate of energy dissipation (entropy production) changes at an infinitesimal variation in the concentration of, for example, substance Aj around its stationary state when the concentrations of the rest of the reactants are constant. The fluctuation in the concentration of Aj results in the fluctuation of parameter Ai by quantity 5Ai to give... 

In this case, upon a fluctuation in the concentration of A2 at the constant concentration of Aj... 

In a general case of catalytic stepwise reactions with a large number of catalytic intermediates, the kinetic methods are indeed preferable to ana lyze the stability of the stationary state of the system. This can be done by considering the evolution of minor fluctuations in the concentrations... 

Depending on the metabolic status within the various compartments of the cell, fluctuations in the concentration of radicals or reactive oxygen species may occur. 

Interest in the rise in plasma glucose levels following consumption of different starchy foods arose because of health concerns for diabetes. Certain diabetics require a specific schedule of energy intake throughout the day. These patients require a constant supply of carbohydrate but must avoid drastic increases or fluctuations in the concentration of plasma glucose. Consequently, their nutritional treatment includes instructions to avoid rapidly absorbed sugars (mono-and disaccharides) and to consume the more slowly absorbed starches. 

As an example of the error that may be induced in NIR measurements by failure to control humidity, fluctuations in the concentration of atmospheric water vapor generated by an air conditioner were identified as a source of noise in NIR spectrometers in a 1987 paper [3]. 

Correlations between the rate of deterioration of the sandstone masonry and fluctuations in the concentrations of acidic components delivered by the local atmosphere can be detected. 

Wide daily fluctuations in the concentrations of plasma tryptophan, as well as of other amino acids, occur in healthy humans.7 Feigin et al.8 reported a diurnal rhythm for total whole-blood amino acid levels in healthy humans. Daily fluctuations have been observed for all of the nutritionally important amino acids.910 A number of investigators have studied factors that may influence diurnal fluctuations of plasma tryptophan in humans.1112 Many reports cite marked variations, usually decreased levels, of plasma tryptophan, under a variety of disease states. However, it is difficult to assess the importance of these observations. 

Figure 5-3 shows the effect of the dispersion coefficient on the tracer distribution in a soil column. Of course, the figure shows a 10-fold increase in dispersion coefficient quickly dampens out fluctuations in the concentration distribution curve leading to a near steady-state concentration profile for x > 200 cm. By con-... 

V.2.4. Brownian Motion and Fluctuations in the Concentration of Disperse Phase Particles... 

In fact there are no violations of the second law of thermodynamics as was incorrectly suspected by the reviewers of the original contributions of Belousov and the reaction is not oscillating between the reactants and final products, but rather there are fluctuations in the concentrations of the intermediates. 

Beats in the dosed flow rates lead to fluctuations in the concentration of the calibration gas. Principally, one cannot assume that an analyzer will show the same results in the case of oscillating concentrations (calibration gas) and in the case of stable concentrations (test gas), even if the mean time value of the concentration is the same in both cases. 

If liquid hydrogen is released in ambient air with a high humidity content, the flammable fiaction of the gas cloud is generally enclosed in the visible cloud, while under conditions of a dry atmosphere, flammable fractions could also exist outside the visible cloud. These observations show that the visible cloud is not a precise indicator for the flairunable zone of the gas cloud [130]. The 4 % lower limit coincides with the perimeter of the visible cloud at temperatures of about 270 - 300 K and humidities of about 50 - 57 %, but with strong fluctuations in the concentration which affect the capability of flame maintenance. 

This gives the equation correlating the mean square value of the fluctuation of polarizability with the corresponding fluctuation in the concentration. It is apparent that the proportionality factor relating these two quantities depends both on the square of the refractive index of the medium and on the square of the refractive increment of the solute. Details of the derivation may be found elsewhere (see for instance Zimm, Stein and Doty, 1945). The final equation, as given by Einstein, furnishes a direct correlation between the turbidity produced by the solute and the change of its osmotic pressure (P) with concentration. 

Consider the titration. Even if the experimental procedure is strictly followed and all operations are made with utmost care, unpredictable fluctuations in the concentrations will always arise. A small change in the viewing angle while reading the burette, a last droplet that remains in the... 

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