Time expressions

Any kinetic process concerns itself with changes occurring over time. Therefore, it is essential to have a clear idea about the meaning of time expressions in pharmacokinetics. These are summarized in Table 2.4. 

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Yet another form for the equations, this time expressed in terms of the can be obtained by substituting for N and the from equations (5.5) into (5.7) and (5,8). After a little rearrangement the result can be written... 

It is also possible to combine (MSF) considerations with evaluation of the true discounted-cash-flow rate of return (DCFRR) by using Eq. (9-62). The relationship of Eq. (9-59) is independent of inflation if all money values are based on those prevailing in the startup year. For this case, Fig. 9-34 shows the true (DCFRR) reached in a given time, expressed as the number of elapsed payback periods for various values of the payback period. 

Particle surface characteristics Type of solid (in terms of internal liquid content) gel, flocculated, hard particle Strength of particle (resistance to deformation under pressure) compressibility over time expressed cake... 

A very useful format in which to display air quality data for analysis is that of Fig. 4-8, which has as its abscissa averaging time expressed in two different time units and, as its ordinate, concentration of the pollutant at the receptor. This type of chart is called an arrowhead chart and includes enough information to characterize fully the variability of concentration at the receptor. 

Capacity The average amount of water circulating in the cooling system at any given time, expressed in gallons per minute. 

The quantity of all gas contained in a reservoir at given time, expressed as the volume expanded to standard conditions. 

Absorbed dose rate This is the absorbed dose per unit time expressed in grays per unit time (kGy/s or kGy/min). Dose rate (Dr) for an electron accelerator [48] can be written in terms of beam current (I) and irradiation field area (A) as follows ... 

The separation time expressed in reduced pareweters is given by equation (6.3)... 

Data Table 1 shows a number of quantities that change with time in a radioactive system. Column one shows the time, expressed in units of the half-life of the radioactive parent. Column two shows the fraction of the original parent nuclei that remain after the indicated number of half-lives. Subtract the value in column two from 1.0 to obtain the fraction of the original parent nuclei that have decayed to daughter nuclei. The final column is the ratio of daughter nuclei to parent nuclei. Complete Data Table 1. 

The computational efficiency of the dynamics in Step 2 on the 2nnd lattice permits the study of the cohesion (and complete mixing) of two thin films [173]. Time scales for equilibration of the density profile, redistribution of chain ends, and complete intermixing of the chains span several orders of magnitude of time, expressed in MC steps, and are all accessible via the 2nnd simulation [173],... 

Absorbed Dose, Chemical—The amount of a substance that is either absorbed into the body or placed in contact with the skin. For oral or inhalation routes, this is normally the product of the intake quantity and the uptake fraction divided by the body weight and, if appropriate, the time, expressed as mg/kg for a single intake or mg/kg/day for multiple intakes. For dermal exposure, this is the amount of material applied to the skin, and is normally divided by the body mass and expressed as mg/kg. 

Rodriguez-Pena A, Ibarrola N, Iniguez MA, Munoz A, Bernal J 1993 Neonatal hypothyroidism affects the timely expression of myelin-associated glycoprotein in the rat brain. J Clin Invest 91 812-818... 

Figure 23. Cost of sterling silver and of pure gold vs. time, expressed in English pennies per troy ounce, a.d. 1000-1950.

The rate of decay of an unstable parent nucleus at any time t is proportional to the number (N) of atoms left (Faure, 1986 38). In other words, the rate at which the number of radioactive nuclei decline is proportional to the number left at that time. Expressed mathematically, this becomes ... 

Fig. 11.10. Schematic illustration of fluorescence correlation spectroscopy. The autocorrelation function characterises the fluctuations of the fluorescence intensity its decay time expresses the average duration of a...

The high DO data, including the nitrifying runs, did not follow a linear relationship, probably because the non-linear relationship of nitrification and residence time [expression (i)]. 

Fig. 2.16 Influence of time, expressed in units of Wy on extent of achievement of steady-state conditions.

The catalytic action of an enzyme, its activity, is measured by determining the increase in the reaction rate under precisely defined conditions—i.e., the difference between the turnover (violet) of the catalyzed reaction (orange) and uncatalyzed reaction (yellow) in a specific time interval. Normally, reaction rates are expressed as the change in concentration per unit of time (mol 1 s see p. 22). Since the catalytic activity of an enzyme is independent of the volume, the unit used for enzymes is usually turnover per unit time, expressed in katal (kat, mol s ). However, the international unit U is still more commonly used (pmol turnover min 1 U = 16.7 nkat). 

Fig. 11. The continuous hydrogenation of dimethyl itaconate using dppf (a) and the dendrimeric ligand 8, (b) conversion (in %) versus time (expressed in reactor volumes pumped through the reactor) (20).

Equation 25 represents particles in the Stokes law regime. Let us develop conversion-time expressions for such particles. 

Combination of Resistances. The above conversion-time expressions assume that a single resistance controls throughout reaction of the particle. However, the relative importance of the gas film, ash layer, and reaction steps will vary as particle conversion progresses. For example, for a constant size particle the gas film resistance remains unchanged, the resistance to reaction increases as the surface of unreacted core decreases, while the ash layer resistance is nonexistent at the start because no ash is present, but becomes progressively more and more important as the ash layer builds up. In general, then, it may not be reasonable to consider that just one step controls throughout reaction. 

Table 25.1 Conversion-Time Expressions for Various Shapes of Particles, Shrinking-Core Model...

The concept of pump throughput is of major significance in practice and should not be confused with the pumping speed The pump throughput is the quantity of gas moved by the pump over a unit of time, expressed in mbar /s the pumping speed is the transportation capacity which the pump makes available within a specific unit of time, measured in m /h or l/s. 

This is the outgassing through a period of time, expressed in mbar I s"l... 

Certainly, Hopi can tell the difference between birds and airplanes, even if the Hopi have one word for things that fly. Via circumlocution, one can usually describe a thing, concept, or emotion with a set of words if one word is not sufficient. However, as we discussed, an individual may have an easier time expressing a concept if there is a word for it. 

Dose rate Dose per unit time, expressed in Gy s = J kgr s E At a constant accelerating voltage, it is proportional to the electron beam current. 

In accordance with the dualistic views of earlier days, the composition of sulphuric acid was at one time expressed by the formula H20.S03, but to-day the formula SQ2(OH)2 is generally adopted, commonly with the assumption of sexavalent sulphur, so that the structural formula is... 

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