Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Accumulation functions

A certain amount of information can be gained by measuring the accumulation of mitotic cells on addition of a mitotic blocking agent. Cultures may be set up as before and colcemid (0.25 /xg/ml) added at zero time. [Pg.203]

If tritiated thymidine is added along with colcemid three accumulation functions can be measured (a) total labelled cells, (b) total mitoses, (c) labelled mitoses, which enables calculation of the length of S and G2 and hence also Gl. [Pg.204]

Thus from Fig. 10.10 it can be seen that an accurate measure of tG2 can be obtained from the distance between the lines which should be parallel if the cell population is exponential and if the tritiated thymidine is not having any deleterious effects on growth. [Pg.204]

The generation time (T) can be obtained from the slope of the line which equals 0.3/T. [Pg.205]

Using the figure for tG2 so obtained a second graph may be drawn (Fig. 10.11) of time against [Pg.205]


In solution culture experiments both strontium and caesium show hyperbolic absorption isotherms with respect to the external concentration of the element. Figure 7-15 (a) shows an example of a typical uptake isotherm for Sr while Shaw and Bell (1989) have demonstrated a similar isotherm for Cs. Baker (1981) has referred to such plant uptake responses as accumulator functions and has identified these as being typical of the absorption of elements over which plants can exert some degree of physiological control. Typically, the nutrient elements, including K and Ca, exhibit such isotherms and it can be postulated from the similarity in the uptake patterns of K and Cs on the one hand and Ca and Sr on the other that the radioions share, to some extent, the same uptake mechanisms as the nutrient ions. This has several important implications. Firstly, the direct competition for uptake sites between radioions and nutrient ions means that the external (soil) concentration of one is increased at the expense of the uptake of the other as the nutrient ions in question are vastly more abundant in soils than radioions it is K and Ca which will be effective in competitively excluding Cs and Sr, respectively. Secondly, the kinetics of this competition are concentration-dependent, so the assumption of first order kinetic movements of... [Pg.210]

Figure 10.9 shows that after a short lag the plot of the accumulation function (log (1 + Nm) where Nm = fraction of mitotic cells) against time is linear. From such a curve the generation time (T) can be calculated either (a) from the equation... [Pg.203]

Imagine for a moment that the exploration activities carried out in the previous section have resulted in a successful discovery well. Some time will have passed before the results of the exploration campaign have been evaluated and documented. The next step will be the appraisal of the accumulation, and therefore at some stage a number of additional appraisal wells will be required. The following section will focus on these drilling activities, and will also investigate the interactions between the drilling team and the other E P functions. [Pg.29]

In Section 5.2.8 we shall look at pressure-depth relationships, and will see that the relationship is a linear function of the density of the fluid. Since water is the one fluid which is always associated with a petroleum reservoir, an understanding of what controls formation water density is required. Additionally, reservoir engineers need to know the fluid properties of the formation water to predict its expansion and movement, which can contribute significantly to the drive mechanism in a reservoir, especially if the volume of water surrounding the hydrocarbon accumulation is large. [Pg.115]

Chemical Properties. Without inhibitors, tetrahydrofurfuryl alcohol is susceptible to autoxidation, developing color and carbonyl functionality. In the absence of air, however, no observable changes occur even after several years storage. In the presence of air, if a stabilizer such as Naugard is added, tetrahydrofurfuryl alcohol remains colorless after protracted periods of storage. Peroxide accumulation is low, not dangerous, and readily dischargeable on redistillation. [Pg.82]

The age pigments (lipofuscin), which accumulate with age, aie largely made up of these precipitated Hpid-proteia complexes resultiag from such cross-linking. Vitamin E may function to help prevent formation of these complexes. The metaboHc role of antioxidants (qv) such as vitamin E in animal tissues, however, remains quite controversial. [Pg.428]

The only commonly used radioisotope in this class is used in small (- IS.S MBq (500 -lCi) injected dose) quantities as a diagnostic for the evaluation of thyroid function. The compound is adininistered as Nal and these procedures are only possible owing to the favorable biological distribution of iodide. Up to 25% of the entire injected dose of iodide is accumulated in the thyroid with a very slow washout the rest is rapidly excreted in the urine. No other compound exhibits so high a ratio of concentration in a target tissue to that of other tissues. [Pg.477]

Several hydrophilic, anionic technetium complexes can be used to perform imaging studies of the kidneys. Tc-Mertiatide (Fig. 5a) is rapidly excreted by active tubular secretion, the rate of which is a measure of kidney function. Tc-succimer (Fig. 5b), on the other hand, accumulates in kidney tissue thus providing an image of kidney morphology. [Pg.479]


See other pages where Accumulation functions is mentioned: [Pg.203]    [Pg.203]    [Pg.206]    [Pg.409]    [Pg.302]    [Pg.207]    [Pg.251]    [Pg.255]    [Pg.426]    [Pg.203]    [Pg.203]    [Pg.206]    [Pg.409]    [Pg.302]    [Pg.207]    [Pg.251]    [Pg.255]    [Pg.426]    [Pg.65]    [Pg.52]    [Pg.803]    [Pg.208]    [Pg.2271]    [Pg.2496]    [Pg.2819]    [Pg.63]    [Pg.265]    [Pg.333]    [Pg.369]    [Pg.92]    [Pg.150]    [Pg.180]    [Pg.198]    [Pg.111]    [Pg.254]    [Pg.288]    [Pg.10]    [Pg.223]    [Pg.385]    [Pg.236]    [Pg.450]    [Pg.148]    [Pg.304]    [Pg.427]    [Pg.481]    [Pg.482]    [Pg.239]    [Pg.483]    [Pg.216]   
See also in sourсe #XX -- [ Pg.203 ]




SEARCH



© 2024 chempedia.info