ABSTRACT
Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials.
ABSTRACT
OBJECTIVE: To further test the application of topical steroids in boys referred to a paediatric surgical practice with pathological, non-retractable foreskins diagnosed as phimosis. PATIENTS AND METHODS: This prospective study comprised two groups of 20 boys each (mean age 4.1 years, range 3-6) diagnosed as having phimosis; twice daily, a topical steroid (0.05% betamethasone cream) was applied on the narrowed preputial skin in the first group and a neutral cream (Vaseline) in the second (control) group. Patients were treated for 4 weeks and the retractability of the foreskin and any side-effects assessed. RESULTS: Good retraction of the foreskin was achieved in 19 patients treated with betamethasone cream and the response was unsatisfactory in 16 patients from the control group; these 16 boys and one 6-year-old boy treated with betamethasone were circumsized. There were no side-effects or problems after the application of either cream. CONCLUSION: Treatment with 0.05% betamethasone cream is a simple and safe method for the treatment of phimosis in boys older than 3 years. An early operation is necessary in cases of genuine phimosis when 1 month of treatment with topical steroids has failed. We strongly support the saying, "The fortunate foreskin of an infant boy will usually be left well alone by everyone but its owner'.
