Visual Search in Radial Menus

Abstract. Menu research has focused predominantly on linear menus (e.g., cascading menus). Little is known about user behavior with radial menus, which have been around for some time. The paper investigates the order in which users find items in radial menus. We analyze data collected in a controlled experiment and define serial position for items laid out in a circular fashion. For the first level (ring), the serial positions start at 12 o’clock position and alternate between both sides of the ring. For subsequent levels, the serial positions follow distance from a parent item. The defined search pattern yields strong fit and has substantial effect on search performance. We discuss the results in the context of radial menu design

Thiolated polymers: Stability of thiol moieties under different storage conditions

The purpose of this study was to evaluate the stability of thiolated polymers - so-called thiomers. A polycarbophil-cysteine conjugate and a chitosan-thioglycolic acid conjugate were chosen as representative anionic and cationic thiomer. The thiol group bearing compounds L-cysteine and thioglycolic acid were introduced to polycarbophil and chitosan, respectively with a coupling reaction mediated by a carbodiimide. The resulting thiolated polymers were freeze-dried and the amount of thiol groups on the thiomer was determined spectrophotometrically. Each kind of polymer was directly used or compressed into 1 mg matrix-tablets. Polymers were stored for a period of six months at four different storage conditions, namely at -20°C (56% relative humidity; RH), 4°C (53% RH), at 20°C (70% RH), and at 22°C (25% RH). Samples were taken after 6 months to determine the formation of disulfide bonds and the remaining thiol groups on the polymer. When the polycarbophil-cysteine and chitosan-thioglycolic acid conjugate were stored as powder a decrease of free thiol groups was observed only after storage at 20°C and 70% RH. Both polymers were found to be stable under all storage conditions when compressed into matrix tablets. The results provide the base for the use of thiomers as auxiliary agents in commercial products