A current review of topical benzoyl peroxide: new perspectives on formulation and utilization.

Benzoyl peroxide (BPO) is the most widely used topical acne treatment, with significant antibacterial, antikeratolytic, and comedolytic activity. It has been shown to be extremely effective as monotherapy and in combination with antibiotics or retinoids for managing comedonal and inflammatory acne lesions. As numerous clinical studies have shown, the combination of BPO plus a topical antibiotic is not only more effective but also is often better tolerated than either agent alone. Unlike antibiotics, no bacterial resistance has been noted. Adding BPO to any long-term antibiotic regimen in acne is generally recommended to help reduce populations of drug-resistant variants. Although effective combinations of BPO and antibiotics or retinoids are used, BPO monotherapy can also be extremely effective in treating mild to moderate acne with no resistance issues.

Experimental investigation on the avoidance of self-excited vibrations.

Self-excited vibrations are observed in many technical applications. Frictional contacts are often involved in the mechanism which generates vibrations. Reasons for the excitation mechanisms are decreasing friction characteristics depending on the sliding velocity, fluctuating normal loads or different geometrical effects. First, the mechanisms are explained using simple examples. The practical relevance of self-excited, friction-induced vibrations is exemplified with three technical systems: a system with an axial seal; a tread block of a tyre; and a disc brake. The knowledge of the excitation mechanism is necessary to introduce successfully design countermeasures. These measures to avoid self-excited vibrations are important to solve practical problems. They are the main focus of this work. Further, additional passive and active subsystems are described and validated experimentally. Therefore, a large range of design, active and passive solutions are given.