Muscle Activation and Subjectively Perceived Effort in Typical Violin Positions.

Violinists display a high incidence of task-specific musculoskeletal problems. Sources pertaining to violin playing and teaching traditions as well as musicians' medicine research offer only imprecise and contradictory recommendations regarding suitable instrument positions. The aim of this study was to add to a growing scientific base for teaching and medical counseling regarding violin positioning. The study evaluated muscle activation (EMG) and subjectively perceived effort (Borg scale) in four standardized typical violin positions, as well as the violinists' normally used one. The hypothesis, the smaller the angle between the instrument's longitudinal axis (LoAx) and the player's central sagittal plane (CSP) and the angle between its lateral axis (LatAx) and the player's horizontal plane (HP), the more muscle activation and perceived effort in the violinist's left arm, was confirmed: Decreasing the LoAx-CSP angle from 50° to 20° and the LatAx-HP angle from 50° to 20° resulted in a highly significant and independent increase of EMG and Borg scale self-ratings mean values. Results may allow for a first step in decision-making on violin positioning for ergonomic adaptations in teaching as well as prevention and therapy of playing-related health problems at all levels of proficiency.

Preferential pi-pi complexation between tamoxifen and borage oil/gamma linolenic acid: transcutaneous delivery and NMR spectral modulation.

The effect of different proportions of borage oil on the in vitro transcutaneous delivery of tamoxifen were studied, with the aim of developing a gel capable of the simultaneous delivery of tamoxifen and gamma linolenic acid across (breast) skin. Supplementary work probed 1H NMR spectral data for tamoxifen in the presence of different proportions of polyunsaturated or unsaturated fatty acids. Typical, non-aqueous gels were modified to contain 1% tamoxifen and three levels of borage oil ( approximately 25% gamma linolenic acid) and the transcutaneous delivery of both tamoxifen and GLA across full thickness skin determined in vitro. Both tamoxifen and gamma linolenic acid permeated the skin with the ratio of moles being consistent at approximately 4:1. This was irrespective of time, amount of borage oil contained in the formulation (above a minimum) and the presence of other (unsaturated) excipients: mineral oil, Miglyiol 810N, white soft paraffin, PEG400 and Cabosil M5. Dose-dependent downfield shifts of tamoxifen aromatic protons were observed in the presence of borage oil and linolenic acid (gamma and alpha), but not saturated triacyl glycerol. The permeation data suggested vehicular complexation between tamoxifen and polyunsaturated constituents of borage oil and that such complexes permeated the skin intact. The 1H NMR data supported the hypothesis that such complexation was a consequence of preferential pi-pi orbital interactions between the phenyl groups of tamoxifen and the multiple double bonds of GLA. The mechanism for the permeation of intact complexes across skin remains to be elucidated.