Permeate time course

The permeation or the mass transfer rate in aqueous film can be obtained from the slope of time course of solute concentration in the feed phase. 

The presence of hollows in cooked rice grains was additionally confirmed for four more cultivars Koshihikari with various amylose contents."" The size, shape and total volume of hollows differed between cultivars. The hypothetical model for the formation of hollows has not been proved experimentally. NMR microimaging was used to determine moisture distribution in boiled Japanese noodles (udon) made from different varieties of wheat.The T2 profile of a piece of boiled udon was monitored in time course measurements during and after boiling. Water permeation from the surface to the core was evaluated by the T2 profile. Effect of moisture distribution on texture of boiled Japanese noodles was discussed. 

Figure 17 Time course of the kinetic experiment performed with surfactant substrate (19) in vesicular 20, Br upon addition of Cu(NO3)2 ([copper(II)] = 5 x 10 M, pH 5). The first part was run at 25 °C, i.e. above the of the membrane. At this temperature the kinetics are monophasic. The second part was run at 10 °C. If during the time at 25 °C copper(II) permeation occurred, monophasic kinetics would be expected since all the substrate (in the internal and external layers) is exposed to the metal ion. Since a biphasic process is observed, no permeation has occurred and the stay of the vesicles above f involves only flip-flop of (19)...

Figure 19 Dependence of the observed rate constant (ktp) for the cleavage of PNPP on the ligand concentration in different vesicular blends (25 °C, [copper(II)] = 1.8xlO- M), (20) and 2Ci6Br, A CTABr, O 2C,6GlyBr, A (21) and 2C (,Br, 2C]5GlyBr, . The inset shows the time course of the absorbance increase observed upon addition of Cu(NO3)2 to the two different vesicular blends (20), (21), O- Only vesicles made of (20) and 2CigBr show clearly biphasic behavior. The fast uptake of copper(II) by the ligand on the outer layer of the bilayer is followed by a much slower process, probably copper(II) permeation...

When leupeptin and E-64 were injected in vivo, the activity of cathepsin B and L in the lysosomal fraction of liver was inhibited within 1 hour and the inhibition persisted for at leeist 6 hours, but gradually disappeared within 36 hours (64) (Fig. 4). There was no difference in the time courses of inhibition by most derivatives of E-64 and leupeptin tested, but some derivatives of E-64 were ineffective in vivo, although they inhibited cathepsin B and L in vitro. Inhibition of cathepsin B and L by injection of leupeptin or E-64 was as marked in the kidney as in the liver, but these compoimds were less effective in skeletal muscle and heart. Hashida et al. (72) showed that E-64 administered in vivo penetrates into lysosomes of the liver, possibly by permeation rather than by endocytosis. When H-labeled E-64 was injected into rats ip, high levels of radioactivity were observed in the serum after a short time and later in the cytosol fraction of liver. While radioactivity in the serum had already decreased 1 hour after the injection, that in the lysosomal fraction increased to a maximum after 6 hours and then gradually decreased (Fig. 5). E-64 was mostly present in the free form in the blood and the c3ftosol fraction but in protein-bound form in the lysosomal fraction. The time course and dose-response of inhibition of lysosomal cathepsin B activity by E-64 was closely correlated with the radioactivity in the protein-bound fraction of the lysosomes. 

Tanaka et al. (2001) used zeolite T membranes in an ISU membrane reactor (at 343 K). Almost complete conversion was reached. The reaction time courses were well described by a model based on two assumptions (1) the reaction obeyed to a second-order kinetic and (2) the permeation flux of each component was proportional to its concentration. 

Figure 15.5 illustrates the time courses of the thickness of fouling layer and the permeate flux in a cross-flow microfiltration system for treatment of paper mill effluent at an axial velocity of 6.97 cm/s. The thickness obtained by UTDR represents cake and fouling layers. As depicted in this figure, the thickness of the... 

Figure 15.5 Time courses of fouling layer thickness and permeate flux at crossflow velocity of 6.97cm/s stop and restart of the fouling operation at 540 min. (Redrawn from [24]).

Here r is the radius of the cylinder into which permeation, to keep the study simple, takes place only through the cylindrical surface, and not through the ends. The time course of mean intracellular concentration can be plotted from the derived equations, for which consult Hill (31) or Jacobs (36) who ves an equivalent form of the equation. See also Rashevsky (72). 

The time course of the permeation of gaseous molecules through membranes showed an induction period followed by permeation with a constant... 

Of course there are many phenomena that equilibrate on the nanosecond timescale. However, the majority of relevant events take much more time. For example, the ns timescale is much too short to allow for the self-assembly of a set of lipids from a homogeneously distributed state to a lamellar topology. This is the reason why it is necessary to start a simulation as close as possible to the expected equilibrated state. Of course, this is a tricky practice and should be considered as one of the inherent problems of MD. Only recently, this issue was addressed by Marrink [56]. Here the homogeneous state of the lipids was used as the start configuration, and at the end of the simulation an intact bilayer was found. Permeation, transport across a bilayer, and partitioning of molecules from the water to the membrane phase typically take also more time than can be dealt with by MD. We will return to this point below. 

The universal medicine is an actual physical substance, produced by alchemical Sages from their own physical bodies. High adepts may entrust the elixir to students, but, of course, the students cannot reproduce it. In appearance, the universal medicine looks like red powder, often referred to as the red tincture, since it permeates all it touches. I had the privilege of guarding the tincture for a period of time. It was produced by a great alchemical Adept of the 20th century. 

Recently it has been claimed that the tissue can be considered viable if the drug permeability does not change over the course of the experiment, and thus the actual permeability experiments themselves may provide insight into the viability of the tissue [109, 157], This method was employed in permeation experiments using porcine buccal mucosa, where the permeability of compounds was assessed in two consecutive permeability experiments to ensure the nature of the barrier was not compromised [111, 112]. While this demonstrates that the barrier nature of the tissue was unaltered between the permeation experiments, the tissue may have already undergone tissue death in the time between the excision and the commencement of the initial permeation experiment, and thus the permeability rate obtained in vitro may not be representative of the in vivo situation. Therefore, more studies assessing the dependence of the barrier nature of the buccal mucosa on tissue viability are... 

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