Modulable steady state

The extraordinarily rapid turnover of HA in tissues suggests that tightly controlled modes exist for modulating steady state levels of HA. The HA of the vertebrate body is of unique importance, and rapid increases are required in situations of extreme stress. Rapid turnover of HA in the normal state... 

Cagnol, F. Grosso, D. Soler-Illia, G.J.D.A.A. Crepaldi, E.L. Babonneau, F. Amenitsch, H. Sanchez, C. Humidity-controlled mesostructura-tion in CTAB-templated silica thin film processing. The existence of a modulable steady state. J. Mater. Chem. 2003, 13 (1), 61-66. 

The scattered intensity of the unperturbed system (Iq) is compensated, and the field-induced light-scattering variations (A/ = /g - Iq) with time are observed directly on the oscilloscope. The dc component of the effect. A/ is determined taking for the middle of the modulated steady-state signal, the ac component - by the amplitude of the steady-state oscillations. The results presented in this chapter were obtained by the use of white unpolarized light. 

The influence of relative himiidity (RH) dining film drying was investigated by GISAXS [79], illustrating the importance of processing conditions that are often considered secondary to chemical conditions. The authors demonstrated the importance of the modulable steady state (MSS), that is, the state that follows... 

Flow which fluctuates with time, such as pulsating flow in arteries, is more difficult to experimentally quantify than steady-state motion because phase encoding of spatial coordinate(s) and/or velocity requires the acquisition of a series of transients. Then a different velocity is detected in each transient. Hence the phase-twist caused by the motion in the presence of magnetic field gradients varies from transient to transient. However if the motion is periodic, e.g., v(r,t)=VQsin (n t +( )q] with a spatially varying amplitude Vq=Vq(/-), a pulsation frequency co =co (r) and an arbitrary phase ( )q, the phase modulation of the acquired data set is described as follows ... 

Amorphous Silicon. Amorphous alloys made of thin films of hydrogenated siUcon (a-Si H) are an alternative to crystalline siUcon devices. Amorphous siUcon ahoy devices have demonstrated smah-area laboratory device efficiencies above 13%, but a-Si H materials exhibit an inherent dynamic effect cahed the Staebler-Wronski effect in which electron—hole recombination, via photogeneration or junction currents, creates electricahy active defects that reduce the light-to-electricity efficiency of a-Si H devices. Quasi-steady-state efficiencies are typicahy reached outdoors after a few weeks of exposure as photoinduced defect generation is balanced by thermally activated defect annihilation. Commercial single-junction devices have initial efficiencies of ca 7.5%, photoinduced losses of ca 20 rel %, and stabilized efficiencies of ca 6%. These stabilized efficiencies are approximately half those of commercial crystalline shicon PV modules. In the future, initial module efficiencies up to 12.5% and photoinduced losses of ca 10 rel % are projected, suggesting stabilized module aperture-area efficiencies above 11%. 

The dependence of the in-phase and quadrature lock-in detected signals on the modulation frequency is considerably more complicated than for the case of monomolecular recombination. The steady state solution to this equation is straightforward, dN/dt = 0 Nss — fG/R, but there is not a general solution N(l) to the inhomogeneous differential equation. Furthermore, the generation rate will vary throughout the sample due to the Gaussian distribution of the pump intensity and absorption by the sample... 

There is nothing in Equations 1-8 which is an all-or-none situation. There are no positive feedback loops which might cause some kind of flip-flop of states of operation of the system. There are some possibilities for saturation phenomena but all relationships are graded. Overall, transient or steady-state, the changes of concentration of P-myosin are continuous, monotonic functions of the intracellular Ca ion concentration. On this basis it is more appropriate to say that smooth muscle contraction is modulated rather than triggered by Ca ion. 

The overall system that we will analyze comprises the unbleached Kraft pulp line, chemicals and energy recovery zones of a specific paper mill (Melville and Williams, 1977). We will employ a somewhat simplified but still realistic representation of the plant, originally developed in a series of research projects at Purdue University (Adler and Goodson, 1972 Foster et al., 1973 Melville and Williams, 1977). The records of simulated operation data, used to support the application of our learning architecture, were generated by a reimplementation, with only minor changes, of steady-state models (for each individual module and the system as a... 

In conclusion, the steady-state kinetics of mannitol phosphorylation catalyzed by II can be explained within the model shown in Fig. 8 which was based upon different types of experiments. Does this mean that the mechanisms of the R. sphaeroides II " and the E. coli II are different Probably not. First of all, kinetically the two models are only different in that the 11 " model is an extreme case of the II model. The reorientation of the binding site upon phosphorylation of the enzyme is infinitely fast and complete in the former model, whereas competition between the rate of reorientation of the site and the rate of substrate binding to the site gives rise to the two pathways in the latter model. The experimental set-up may not have been adequate to detect the second pathway in case of II " . The important differences between the two models are at the level of the molecular mechanisms. In the II " model, the orientation of the binding site is directly linked to the state of phosphorylation of the enzyme, whereas in the II" model, the state of phosphorylation of the enzyme modulates the activation energy of the isomerization of the binding site between the two sides of the membrane. Steady-state kinetics by itself can never exclusively discriminate between these different models at the molecular level since a condition may be proposed where these different models show similar kinetics. The II model is based upon many different types of data discussed in this chapter and the steady-state kinetics is shown to be merely consistent with the model. Therefore, the II model is more likely to be representative for the mechanisms of E-IIs. 

Steady-state component and solvent mass balances can be written for single-pass operation by considering an incremental area element dA in the axial or flow direction for a feed channel, module, or membrane... 

The module system consists of three ideally mixed sections, separated by two membranes. Overall steady-state balances can be used to check the solution and are as follows ... 

The aforementioned experiments at rotating electrodes concerned merely steady-state conditions so-called transients123 at these electrodes, e.g., with potential or current steps, as well as with hydrodynamic modulation, i.e., variation of co with time, are, as a consequence of their non-steady-state conditions, less important in analysis and therefore will not be treated here. 

S02 emitted from the modulated bed goes through a minimum after switching to the S03/S02 mixture. Lowest values are obtained 2 min after the composition change for the sulfur burning feed and they are about 8% of the steady-state emission, whereas for the smelter effluent feed, the lowest emission is about 13% of the steady-state value. Evidently, a cycle period of 4 to 5 min would be optimum for the conditions used, yielding a performance some 10% better than that shown at r = 10 in Table II. 

A critical feature of the random ternary complex mechanism is that for either substrate the dissociation constant from the binary enzyme complex may be different from that of the ternary enzyme complex. For example, the Ks value for AX dissociation from the E AX complex will have a value of K v<. The affinity of AX for the enzyme may, however, be modulated by the presence of the other substrate B, so that the dissociation constant for AX from the ternary E.AX.B complex may now be c/Xax, where a is a constant that defines the degree of positive or negative regulation of the affinity of AX for the enzyme by the other substrate. The overall steady state velocity equation for this type of mechanism is given by Equation (2.15) ... 

PESTAN (12) is a dynamic TDE soil solute (only) model, requiring the steady-state moisture behavior components as user input. The model is based on the analytic solution of equation (3), and is very easy to use, but has also a limited applicability, unless model coefficients (e.g., adsorption rate) can be well estimated from monitoring studies. Moisture module requirements can be obtained by any model of the literature. 

A small square wave modulation of the current is applied in order to disturbe the non-equilibrium steady state of the discharge. The exponential decay of the concentrations leads to characteristic relaxation times, which allow the calculation of rate constants used in the modeling of the deposition mechanism. 

Ambudkar, S. V., Correlation between steady-state ATP hydrolysis and vanadate-induced ADP trapping in human P-glycoprotein. Evidence for ADP release as the rate-limiting step in the catalytic cycle and its modulation by substrates, J. Biol. Chem. 2001, 276, 8657-8664. 

Bolometric signals, as we said, are modulated at a frequency co. Very rarely bolometers are used to detect pulsed signals or steady-state radiation levels. 

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