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SUMMARY1. The whole-cell patch-clamp technique was used to investigate the characteristics of two types of sodium current (INa) recorded at room temperature from small diameter (13-25 /Lm) dorsal root ganglion (DRG) cells, isolated from adult rats and maintained overnight in culture.2. Sodium currents were isolated pharmacologically. Internal Cs' and external tetraethylammonium (TEA) ions were used to suppress potassium currents. A combination of internal EGTA, internal F-, a low (10 gbM) concentration of external Ca2' and a relatively high (5 mM) concentration of internal and external Mg2+ was used to block calcium channels. The remaining voltage-dependent currents reversed direction at the calculated sodium equilibrium potential. Both the reversal potential and magnitude of the currents exhibited the expected dependence on the external sodium concentration.3. INa subtypes were characterized initially in terms of their sensitivity to tetrodotoxin (TTX). TTX-sensitive (TTX,) currents were at least 97 % suppressed by 041 /LM TTX. TTX-resistant (TTXr) INa were recorded in the presence of 0 3 ftM TTX and appeared to be reduced in amplitude by less than 50% in 75 /tM TTX (n= 1).4. As in earlier studies, the peak of the current-voltage relationship, the mid-point of the normalized conductance curve and the potential (Vh) at which the steady-state inactivation parameter (hoo) was 0-5 were found to be significantly more depolarized for the TTXrINa (by ca 10, 14 and 37 mV respectively). There was little difference in the slope at the mid-point of the normalized conductance curves (the mean slope factors were 5-1 mV for the TTX, INa and 4-9 mV for the TTXr current) but the h., curves for TTXr currents were significantly steeper than those for TTXS currents (mean slope factors of 3-8 and 11-5 mV respectively). Both the time to peak and the decay time constant of the peak current recorded from a holding potential of -67 mV were more than a factor of three slower for the TTXr INa than for the TTXS current.5. However, in direct contrast to the difference in activation and decay kinetics, 'slow' TTX. INa recovered from inactivation at -67 mV, or reprimed, more than a factor of ten faster than 'fast' TTXS INa. 7. The possible fundamental importance to DRG cells of such large differences in the voltage dependence of the inactivation systems (both resting inactivation and repriming kinetics) of the two sodium channel subtypes will be discussed.

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Survey data support hypotheses regarding differential access to workplace power among women and minorities relative to white men. Specific findings indicate that, relative to white men, all groups encounter increasing inequality at higher levels of power, but only black women seem to experience this form of inequality as a result of direct discrimination. Further analysis indicates that network assistance is more a response to this form of discrimination than an indirect cause. Finally, analysis shows that most groups attain power through homosocial reproduction, but what differs is the opportunity to engage in such reproduction, wherein white men excel. These findings imply that while women and minorities face lower odds than white men of achieving higher levels of workplace power, the reasons for this disadvantage vary among respective groups and thus will likely require different remedies.

Small-angle X-ray scattering (SAXS) and bulk volumetric measurements were performed on the perfluorinated ionomer membrane "Nafion". The swelling experiments were conducted using controlled environments of different relative humidities. The membranes were oriented using uniaxial draw, both before and after conversion of the precursor material, as well as both sequential and simultaneous biaxial draw. Using a novel model-independent maximum entropy method, it is shown that the most statistically probable scattering model for Nafion is an ion clustered morphology with a hierarchical scale of structure. The smallest scale is comprised of arrays of roughly spherical ionic clusters. The clusters are agglomerated into higher-order structures, whose shape is determined by the spatial coherence of the clusters, as inferred from the SAXS measurements. Anomalies in the magnitudes of the microscopic and macroscopic swellings are shown to be caused by the rearrangement of ionic material, producing changes in the number density of clusters.