Temporal variations of CO2 efflux continuous monitoring at the summit cone of Teide volcano (Tenerife, Canary Islands) during the period1999-2021

<p>Tenerife Island (2034 km<sup>2</sup>), the largest of the Canarian archipelago, is characterized by three main volcano-tectonic axes: the NS, NE and NW rifts and a central caldera, Las Cañadas, hosting the twin stratovolcanoes Pico Viejo and Teide. Although Teide volcano hosts a weak fumarolic system, volcanic gas emissions from the summit cone consist mostly of diffuse CO<sub>2</sub> degassing. The first continuous automatic geochemical station in Canary Islands was installed at the south-eastern foot of summit cone of Teide volcano in 1999, with the aim of improving the volcanic monitoring system and providing a multidisciplinary approach to the surveillance program of Teide volcano. The 1999-2020 time series shows diffuse CO<sub>2</sub> emission values ranging between 0 and 62.8 kgm<sup>-2</sup>d<sup>-1</sup>, with a mean value of 4.3 kgm<sup>-2</sup>d<sup>-1</sup>. Inspection of the CO<sub>2</sub> efflux time series shows significant temporal variations with anomalous values of more than 20 kgm<sup>-2</sup>d<sup>-1</sup> centred at years 2000, 2003, 2005, 2007, 2008, 2012, 2015 and 2016, always before a significant increase in the seismic activity beneath Tenerife Island. With the aim to filter out environmental variables, a multiple regression analysis (MRA) was applied to the first 12 years of the diffuse CO<sub>2</sub> flux time series (1999-2011), recorder on an hourly basis by the station, and we found that soil temperature, soil water content, wind speed and barometric pressure explained 16.7% of variability. The comparison between filtered CO<sub>2</sub> efflux (continuous, hourly, automated station) versus the temporal evolution of diffuse CO<sub>2</sub> emission estimated by ground CO<sub>2</sub> efflux surveys of summit cone of Teide (during summer season on an area of around 0.11 km<sup>2</sup>) for the period 1999-2011 (Pérez et al., 2013), shows a nearly coincident marked peak in December 2001 and a similar shaped evolution from each sampling type as the increase from ~2005 to 2009 and the subsequent decrease from ~2009 to 2011, reaching maximum values of 161.6 and 179.9 t d<sup>-1</sup>, respectively. Seismic activity displayed as of monthly earthquakes (M>1) occurring in and around Tenerife island is well correlated with diffuse CO<sub>2</sub> efflux relevant peaks. In average, the seismicity recorded during the study period was mainly preceded by geochemical anomalies of the registered surface CO<sub>2</sub> efflux by about one year. After we analysed the CO<sub>2</sub> efflux time series by using the Continuous Wavelet Transform (Ricker wavelet) to detect relevant time-frequency patterns in the signal, we found at low frequencies quasi-periodical oscillations with periods of 3-4 years, which might reflect the internal dynamics of the magmatic-hydrothermal system. Moreover, during the intervals of highest levels of CO<sub>2</sub> efflux, the analysis evidenced also oscillations with a period of about 6 months during the interval 1999-2011. Our study reveals that continuous geochemical monitoring data is representative of the same trends in flux that are quantitatively captured by annual surveys, and provides the basis for accurate determination of background values. This combined approach offers a useful template for application to other volcanic systems for the purposes of constructing quantitative dynamic models of hydrothermal systems and identifying processes at depth in near-real-time.</p>

Study of Electromagnetic Effect Parameters Influence on Fluidity of Fine Nd-Fe-B Powder

The paper experimentally proves the efficiency of electromagnetic effect on stimulated fluidity of magneto-hard powders. Fine Nd-Fe-B powder doesn’t have natural fluidity. To make it flow through hopper outlet we effected on the powder by constant and alternating gradient magnetic fields. Induction lines of constant magnetic field were horizontal, and alternating field lines were vertical. In order to form stimulated powder fluidity, higher induction gradient was situated below the powder receiver chamber. We experimentally found optimal magnetic fields parameters that form steady magneto fluidized bed from Nd-Fe-B powder, with an average particle size 1 μm. The study results of influence of magneto fluidized bed electromagnetic parameters on Ne-Fe-B powder efflux speed through outlets with diameters 1 and 2 mm are presented. Gradient field topology and parameters of electromagnetic effect providing minimal efflux time of 1000 mg of powder are defined.

Effects of Electroacupuncture on the Daily Rhythmicity of Intestinal Movement and Circadian Rhythmicity of Colonic Per2 Expression in Rats with Spinal Cord Injury

Background. Spinal cord injury (SCI) leads to bowel dysfunction. Electroacupuncture (EA) may improve bowel function. Objective. To assess EA on daily rhythmicity of intestinal movement and circadian rhythmicity of colonic Per2 expression in rats with SCI. Methods. Rats were randomized to the sham, SCI, and SCI+EA groups. EA was performed at bilateral Zusanli point (ST36) during daytime (11:00–11:30) for 14 days following SCI. Intestinal transit and daily rhythmicity of intestinal movement were assessed. Circadian rhythmicity of colonic Per2 expression was assessed by real-time RT-PCR. Results. EA shortened the stool efflux time and increased the dry fecal weight within 24 h in SCI rats. Daily rhythmicity of intestinal movements was unaffected by SCI. The expression of colonic Per2 peaked at 20:00 and the nadir was observed at 8:00 in the SCI and sham groups. In the SCI+EA group, colonic Per2 expression peaked at 12:00 and 20:00, and the nadir was observed at 8:00. Conclusion. SCI did not change the circadian rhythmicity of colonic Per2 expression in rats, and daily intestinal movement rhythmicity was retained. EA changed the daily rhythmicity of intestinal movement and the circadian rhythmicity of colonic Per2 expression in rats with SCI, increasing Per2 expression shortly after EA treatment.

Abstract 17232: Comparison of Methods for the Measurement of Cholesterol Efflux Capacity of Plasma HDL With J774 Mouse Macrophages Reveals Superiority of the Radioactive Cholesterol Method over the BODIPY-Cholesterol-2 Method

Recent clinical studies suggest that raising HDL-cholesterol (HDL-C) concentration is insufficient to lower cardiovascular risk and that protection derives from other characteristics of HDL particles. One such characteristic that can be measured in vitro is the cholesterol efflux capacity of plasma, an assay where HDL accepts labelled cholesterol from macrophages. Recently, a method for the measurement of cholesterol efflux with a fluorescent tracer, BODIPY-cholesterol-2 (BC2), has been proposed as an alternative to the radioactive method. We undertook a systematic comparison of BC2 and 3H-cholesterol methods with J774 macrophages in basal and cAMP-stimulated conditions with purified acceptors, plasma from healthy volunteers and patients with myocardial infarction of the Montreal Heart Institute Biobank. Dose-response curves show higher affinity of BC2 vs. 3H cholesterol with apoA-I, HDL and apoB-depleted plasma (all p<0.01) and a higher maximal efflux for HDL and depleted plasma (both p<0.001) in stimulated conditions. This was reflected in a faster kinetics of BC2 efflux compared to 3H-cholesterol efflux (time for half-maximal efflux 4.1h vs. 10.2 h) and resulted in a 2.5-fold increase of BC2 maximal efflux (p<0.01). With 50 normolipidemic plasmas (2.8%, 4h efflux), the two methods were not correlated in basal conditions (r2=0.079) and strongly correlated in stimulated conditions (r2=0.830). BC2 values did not correlate with HDL-C in all conditions, contrary to 3H cholesterol values (p<0.01). Using more complex samples from patients with MI (n=115), the correlations were modest in basal (r2=0.219) and stimulated (r2=0.400) conditions. Differences between controls and MI cases showed reduced significance with BC-2 compared to 3H cholesterol. Lastly, in macrophages examined under the confocal microscope, BC2 labels vesicular structures colocalized with filipin, a free cholesterol marker, suggesting endosomal loading of BC2. Thus, the BC2 method is not equivalent to the classic 3H cholesterol method for cholesterol efflux measurement.