Mechanisms for Stable Sonoluminescence

A gas bubble trapped in water by an oscillating acoustic field is expected to either shrink or grow on a diffusive timescale, depending on the forcing strength and the bubble size. At high ambient gas concentration this has long been observed in experiments. However, recent sonoluminescence experiments show that in certain circumstances when the ambient gas concentration is low the bubble can be stable for days. This paper presents mechanisms leading to stability which predict parameter dependences in agreement with the sonoluminescence experiments.Comment: 4 pages, 3 figures on request (2 as .ps files

Effect of Transdermal Magnesium Cream on Serum and Urinary Magnesium Levels in Humans: A Pilot Study

© 2017 Kass et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background Oral magnesium supplementation is commonly used to support a low magnesium diet. This investigation set out to determine whether magnesium in a cream could be absorbed transdermally in humans to improve magnesium status. Methods and findings In this single blind, parallel designed pilot study, n=25 participants (aged 34.3+/-14.8y, height 171.5+/-11cm, weight 75.9 +/-14 Kg) were randomly assigned to either a 56mg/day magnesium cream or placebo cream group for two weeks. Magnesium serum and 24hour urinary excretion were measured at baseline and at 14 days intervention. Food diaries were recorded for 8 days during this period. Mg test and placebo groups’ serum and urinary Mg did not differ at baseline. After the Mg2+ cream intervention there was a clinically relevant increase in serum magnesium (0.82 to 0.89 mmol/l,p=0.29) that was not seen in the placebo group (0.77 to 0.79 mmol/L), but was only statistically significant (p=0.02)) in a subgroup of non-athletes . Magnesium urinary excretion increased from baseline slightly in the Mg2+ group but with no statistical significance (p=0.48). The Mg2+ group showed an 8.54% increase in serum Mg2+ and a 9.1% increase in urinary Mg2+ while these figures for the placebo group were smaller, i.e. +2.6% for serum Mg2+ and -32% for urinary Mg2+. In the placebo group, both serum and urine concentrations showed no statistically significant change after the application of the placebo cream. Conclusion No previous studies have looked at transdermal absorbency of Mg2+ in human subjects. In this pilot study, transdermal delivery of 56 mg Mg/day (a low dose compared with commercial transdermal Mg2+ products available) showed a larger percentage rise in both serum and urinary markers from pre to post intervention compared with subjects using the placebo cream, but statistical significance was achieved only for serum Mg2+ in a subgroup of non-athletes. Future studies should look at higher dosage of magnesium cream for longer durations.Peer reviewe

Influence of Trans-dermal Magnesium vs placebo cream application on Serum and Urinary Magnesium Concentrations (mean +/- S.D.) for non-athlete subjects.

<p>Influence of Trans-dermal Magnesium vs placebo cream application on Serum and Urinary Magnesium Concentrations (mean +/- S.D.) for non-athlete subjects.</p

Demographic and baseline serum, urine and dietary magnesium (mean +/- s.d. [range]) for non-athletes only.

<p>Demographic and baseline serum, urine and dietary magnesium (mean +/- s.d. [range]) for non-athletes only.</p

Demographic and baseline serum, urine and dietary magnesium (mean +/- s.d. [range]) for all subjects, athletes plus non-athletes.

<p>Demographic and baseline serum, urine and dietary magnesium (mean +/- s.d. [range]) for all subjects, athletes plus non-athletes.</p

CONSORT flow diagram, showing inclusion and exclusion of participants in the study.

<p>CONSORT flow diagram, showing inclusion and exclusion of participants in the study.</p