Fracture and damage localization in volcanic edifice rocks from El Hierro, Stromboli and Tenerife

© 2018 The Author(s). We present elastic wave velocity and strength data from a suite of three volcanic rocks taken from the volcanic edifices of El Hierro and Tenerife (Canary Islands, Spain), and Stromboli (Aeolian Islands, Italy). These rocks span a range of porosity and are taken from volcanoes that suffer from edifice instability. We measure elastic wave velocities at known incident angles to the generated through-going fault as a function of imposed strain, and examine the effect of the damage zone on P-wave velocity. Such data are important as field measurements of elastic wave tomography are key tools for understanding volcanic regions, yet hidden fractures are likely to have a significant effect on elastic wave velocity. We then use elastic wave velocity evolution to calculate concomitant crack density evolution which ranges from 0 to 0.17: highest values were correlated to the damage zone in rocks with the highest initial porosity

Bioluminescent imaging of Cdk2 inhibition in vivo

Many proteins and pathways of pharmaceutical interest impinge on ubiquitin ligases or their substrates. The cyclin-dependent kinase (Cdk) inhibitor p27, for example, is polyubiquitylated in a cell cycle−dependent manner by a ubiquitin ligase complex containing the F-box protein Skp2. Regulated turnover of p27 is due, at least partly, to its phosphorylation by Cdk2 on threonine 187, which generates a Skp2-binding site. We made a p27-luciferase (p27Luc) fusion protein and show here that its abundance, like that of p27, is regulated by Skp2 in a cell cycle−dependent manner. As predicted, p27Luc levels increased after blocking Cdk2 activity with inhibitory proteins, peptides or small interfering RNA (siRNA). Accumulation of p27Luc in response to Cdk2 inhibitory drugs (flavopiridol and R-roscovitine) was demonstrable in human tumor cells in vivo using noninvasive bioluminescent imaging. In theory, the approach described here could be used to develop bioluminescent reporters for any drug target that directly or indirectly affects the turnover of a ubiquitin ligase substrate

Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes

Despite recent technological advances in volcano monitoring, eruption forecasting is still inadequate. Improved forecasting requires a deeper understanding of when unrest will lead to an actual eruption. Shallow Long Period (low spectral frequency) seismic events are routinely employed as a primary tool in forecasting strategies as they often precede eruptions. They are universally explained as resonating fluid-filled cracks or conduits, indicating the presence of mechanically active near-surface fluids. We undertake very high resolution seismic field experiments at Mt Etna, Italy; Turrialba, Costa Rica and Ubinas, Peru, in which we find that seismogram resonance is propagation path related whilst the seismic sources comprise short pulses. Data analysis and numerical modelling show that slow-rupture failure in unconsolidated volcanic materials reproduces all key aspects of these new observations. Contrary to current interpretations, here we show that our observed Long Period events are not direct indicators of fluid presence/migration, but rather are markers for upper edifice deformation. This finding encapsulates this seismicity within growing observations of a spectrum of deformation rates in other non-volcanic environments, from slow-slip earthquakes through fast dynamic rupture. It calls for a reassessment of how lowfrequency seismic signals are interpreted in their key role in eruption forecasting.AD 17/02/201