Pore shape funnel-shaped

Fig. 4.2. Some idealised pore structures (a) cylindrical pores (ai,a2 parallel non-intersecting capillaries ai t = 1 a2 t > 1 as non-parallel intersecting capillaries (b) slit-shaped pores (c) voids between packed spheres (d) closed pores (e) blind pores (f) open pores (g) funnel (h) ink bottle ...

For the measurement of pore sizes on the membrane, the geometry of the tip is also important. The pore sizes or funnel shape of pore entrances determined by AFM depend on the convolution between tip shape and pore shape as illustrated in Fig. 5.5. In this figure, AFM traces for two different membrane models (cylindrical and funnel-shaped with two different pore sizes) and an idealized round-shaped tip. Only in model A can surface diameter be measured accurately from the tip traces. 

Shape of pore-canal funnel-shaped (0) flask-shaped (1). 

ACh receptors are present in the post-junctional membrane of the endplate, in the junctional folds. The nicotinic ACh receptor at the motor endplate has five subunits, two os, (3, 5 and . In addition, a Y subunit instead of an e subunit may be present in the so-called extra-junctional or the fetal receptor. The five subunits are arranged as a cylinder around a central funnel-shaped pore, the ion channel. The two a subunits each carry a recognition site which binds nicotinic agonists such as ACh and antagonists such as the neuromuscular blocking agents. Whilst ACh must bind to both subunits to produce an effect, it is sufficient for... 

It is believed that the number of micropores so produced was not affected by the water vapour pressure, but that the pores were widened as the pressure was increased. This would explain the results in Figure 10.18b, where the steep increase in a a(BET) under 1 mbar pressure was due to appreciable micropore widening in contrast to the smaller rate of increase of a(BET) when the water vapour pressure was suddenly reduced to 0.04 mbar in this way funnel-shaped micropores were obtained. 

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