Surface coupling effects on the capacitance of thin insulating films

A general form for the surface roughness effects on the capacitance of a capacitor is proposed. We state that a capacitor with two uncoupled rough surfaces could be treated as two capacitors in series which have been divided from the mother capacitor by a slit. This is in contrast to the case where the two rough surfaces are coupled. When the rough surfaces are coupled, the type of coupling decides the modification of the capacitance in comparison to the uncoupled case. It is shown that if the coupling between the two surfaces of the capacitor is positive (negative), the capacitance is less (higher) than the case of two uncoupled rough plates. Also, we state that when the correlation length and the roughness exponent are small, the coupling effect is not negligible

Pimecrolimus cream in repigmentation of vitiligo

Background: Vitiligo is a chronic disease that mostly affects children and young adults. Nowadays many treatment options are available; however, most of them have limited efficacy and in most cases would result in undesirable complications. Objective: To determine the extent of repigmentation according to the location of the lesions after applying topical cream pimecrolimus 1 in vitiligo patients. Materials and Methods: Thirty consecutive patients with vitiligo lesions affecting less than 20 of body surface area without any previous history of spontaneous repigmentation were treated with pimecrolimus cream 1 twice daily for 12 weeks. The extent of repigmentation in vitiligo lesions was determined in each patient after 6 and 12 weeks. Results: Moderate to excellent response (repigmentation >26) was observed in 6.6 and 25.9 of vitiligo lesions 6 and 12 weeks after treatment, respectively. More responsive lesions were located on the trunk, face and elbow (85.7, 75 and 70). Conclusion: Pimecrolimus cream 1 results in repigmentation in vitiligo in different extents according to the location of the lesion; however, to clearly prove its efficacy as monotherapy or in combination with other available treatment options, double-blind placebo-controlled studies are essential. Copyright © 2007 S. Karger AG