Pulse protocols

So now we have a modified method where one has ammonia, methylamine or ethylamine freebase saturated in a small amount of DMF. The author next suggested that a power pulse protocol would not necessarily be needed, but that the power output from the microwave should be between 20-40% of full power. Also, the water in the clay would still be needed for the reaction. 

The slowly dissociating state appears to reflect receptor in an inactive form. Cells can be stimulated in a pulse protocol in which the stimulus (FLPEP) is added, then at some later time, its binding to the receptor is interrupted by the addition of an antibody to fluorescein or of a receptor antagonist (tBoc-phe-leu-phe-leu-phe). 

As shown by ERs (Table 15.1), both pulsing protocols significantly increased the penetration of estradiol and L-glutamic acid in relation to their respective steady-state passive fluxes... 

Apparent Fluxes of Estradiol and L-Glutamic Acid through Human Epidermis During a Three Stage Experiment for Two Pulsing Protocols. Enhancement Ratios and Damage Ratios for Both Compounds are also Given (n = 3)... 

In order to study the kinetics of disulfide bond reduction as a function of the pulling force, we utilize a double pulse protocol in force clamp. With a first pulse, we unfold the unsequestered region of the (I27s-s)8 modules in the polyprotein, exposing the disulfide bonds to the solution. With a second (test) pulse, we track the rate of reduction of the exposed disulfides at various pulling forces in the presence of various reducing agents. 

Fig. 17.8. Double pulse protocol designed to measure the force dependency of the reduction of the disulfide bonds of a (127s-s)s polyprotein. The first pulse triggers unfolding, causing a series of 11 nm steps. In the presence of SpM E. Colt Thiore-doxin, unfolding is followed by a series of 13.5 nm steps that mark the reduction events. A test pulse (shown to 100 pN) is used to probe the force dependency of the reaction. In the absence of thioredoxin, the 13.5 nm steps are never observed...

As the prediction was that the refractory period would increase as a result of a slower recovery from inactivation, we tested the effect of DHA on the time-course of the recovery from inactivation. Using a double-pulse protocol, the current was first completely inactivated by a 20-ms conditioning pulse to -25 mV. After a recovery period of increasing duration at either -70 mV or -80 mV, the fraction of channels that were recovered from inactivation was assessed with a second pulse to -25 mV (Fig. 4D). The recovery from inactivation as a function of interval was fit by an exponential function with a time... 

Figure 3. Sodium currents recorded from the squid giant axons before (A) and after (B) internal application of 10 pM deltamethrin. External and internal sodium concentrations were 111 mM and 50 mM, respectively. A, a depolarizing pulse from the holding potential (V ) of -80 mV to -20 mV elicited the normal transient inward sodium current which decayed within 10 msec. Depolarization to a second depolarizing pulse (500 msec) to the sodium reversal potential (E a - +20 mV) yielded a negligible current. Repolarization to the holding potential (-80 mV) produced a very small inward sodium tail current. B, the same pulse protocol as that for A but in the presence of deltamethrin in another axon Note a large and prolonged tail current upon repolarization from +20 mV to -80 mV.

Sodium currents were evoked by voltage pulses from a holding potential of —90 mV to a membrane potential, of —60 to +80 mV for 3 ms (Fig. lOA). All stimulation for sodium currents was followed by a similar pulse protocol in which the pulse amplitude was reduced to 1/4 and the holding potential was brought to —120 mV (P/4 protocol [42]). A plot of the peak current as a function of the membrane potential is shown in Fig. lOB. The peak current was estimated by a cubic fit of each record in a short interval around the peak with a third-order polynomial. The reversal potential, V, i.e., the applied voltage for which the peak current changes sign is estimated around 53 mV, which is very close to the Nernst equilibrium potential for sodium ions in these experimental conditions. 

The corresponding calculations can be simply performed by using a spreadsheet program. The validity of this approach is confirmed by the exact reproduction of the theoretical description based on explicit solutions. It has also been used to evaluate a double-pulse protocol applied for thin-layer coulometric ISM electrodes in order to reduce the level of interference. ... 

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