Irreversibility and Polymer Adsorption

Physisorption or chemisorption from dilute polymer solutions often entails irreversible polymer-surface bonding. We present a theory of the non-equilibrium layers which result. While the density profile and loop distribution are the same as for equilibrium layers, the final layer comprises a tightly bound inner part plus an outer part whose chains make only fN surface contacts where N is chain length. The contact fractions f follow a broad distribution, P(f) ~ f^{-4/5}, in rather close agreement with strong physisorption experiments [H. M. Schneider et al, Langmuir v.12, p.994 (1996)].Comment: 4 pages, submitted to Phys. Rev. Let

Stress management and erectile dysfunction: A pilot comparative study

Summary: Erectile dysfunction (ED) is a complex disorder with various biopsychosocial implications leading the individual into a state of chronic stress that further worsens ED symptoms. The aim of this study is to investigate the effects of a 8-week stress management programme on erectile dysfunction (ED). A convenience sample of 31 newly diagnosed men with ED, aged between 20 and 55 years, was recruited during a period of 5 months to receive either tadalafil (12 patients) or tadalafil and the 8-week stress management programme. Both groups showed statistical significant improvement of both perceived stress and erectile function scores. Men practising stress management showed a statistical significant reduction in perceived stress score compared with men receiving tadalafil alone. No other statistical significant differences were noted between the two groups, although the stress management group showed a lower daily exposure to cortisol compared with the control group after 8 weeks. Finally, perceived stress and cortisol showed some interesting correlations with sexual function measurements. These findings provide important insight into the role of stress management, as part of the recommended biopsychosocial approach, in ED. Future studies should focus on randomised, controlled trials with larger samples and longer follow-up time. © 2013 Blackwell Verlag GmbH