Integrated QCM-Microtribometry: Friction of Single-Crystal MoS2 and Gold from µm/s to m/s.

Two opposing microtribometry approaches have been developed over the past decade to help connect the dots between fundamental and practical tribology measurements: spring-based (e.g., AFM) approaches use low speed, low stiffness, and long relative slip length to quantify friction, while quartz crystal microbalance (QCM)-based approaches use high speed, high stiffness, and short relative slip length. Because the friction forces generated in these experiments are attributed to entirely different phenomena, it is unclear if or how the resulting friction forces are related. This study aims to resolve this uncertainty by integrating these distinct techniques into a single apparatus that allows two independent measurements of friction at a single interface. Alumina microspheres were tested against single-crystal MoS2, a model nominally wear-free solid lubricant, and gold, a model metal control, at loads between 0.01 and 1 mN. The combined results from both measurement approaches gave friction coefficients (mean ± standard error) of 0.087 ± 0.007 and 0.27 ± 0.02 for alumina-MoS2 and alumina-gold, respectively. The observed agreement between these methods for two different material systems suggests that friction in microscale contacts can be far less sensitive to external effects from compliance and slip speed than currently thought. Perhaps more importantly, this Article describes and validates a novel approach to closing the "tribology gap" while demonstrating how integration creates new opportunities for fundamental studies of practical friction.

Changes in psychic and somatic well-being and cognitive capabilities of peri- and postmenopausal women after the use of a hormone replacement drug containing estradiol valerate and levonorgestrel.

A multicenter, prospective, open-label postmarketing surveillance study examined to what extent 2-month oral hormone replacement therapy (estradiol valerate and levonorgestrel; Klimonorm) could produce changes in psychosomatic well-being, self esteem and cognitive capabilities in 78 peri- and postmenopausal women. The women included were 42-58 years of age and had approached the physician due to climacteric symptoms. The following tests were used: Kupperman index, Menopause Rating Scale (MRS II), General Depression Scale (ADS), Zerssen's Symptom List (B-L), Frankfurt Self-Concept Scales (FSAL, FSAP, FSEG, FSSW), Digit Symbol Substitution Test (DSST), d2 Test of Attention and Number Square Test. The results showed a clear improvement in subjective psychosomatic well-being and improvements to a lesser extent in the concentration and cognitive capabilities in women in the third treatment cycle.