Observation of Rayleigh-Lamb waves generated by the 2022 Hunga-Tonga volcanic eruption with the POLA detectors at Ny-Ålesund.

The eruption of the Hunga-Tonga volcano in the South Pacific Ocean on January 15, 2022, at about 4:15 UTC, generated a violent explosion, which created atmospheric pressure disturbances in the form of Rayleigh-Lamb waves detected all over the globe. Here we discuss the observation of the Hunga-Tonga shock-wave performed at the Ny-Ålesund Research Station on the Spitsbergen island, by the detectors of the PolarquEEEst experiment and their ancillary sensors. Online pressure data as well as the results of dedicated offline analysis are presented and discussed in details. Results include wave arrival times, wave amplitude measurements and wave velocity calculation. We observed five passages of the shock wave with a significance larger than 3 [Formula: see text] and an amplitude up to 1 hPa. The average propagation velocity resulted to be (308 ± 0.6) m/s. Possible effects of the atmospheric pressure variation associated with the shock-wave multiple passages on the cosmic-ray rate at ground level are also investigated. We did not find any significant evidence of this effect.

The retinoid induced pancreatic cancer redifferentiation-apoptosis sequence and the mitochondria: a suggested obligatory sequence of events.

Retinoic acid induces redifferentiation and apoptosis in pancreatic adenocarcinoma cell lines. Redifferentiation includes early reversion into aerobic metabolism as reflected by an increase of mitochondrial activity and mass with normal membrane potential and terminal ductal cell differentiation. Cells in such a state either attempt to correct their DNA abnormalities or commit suicide by apoptosis. In some cell systems, such as pancreatic ductal cells, the stem cells show potential to transdifferentiate into functional normal endocrine cell type. However, since it is impossible to correct a highly corrupted genome, cells eventually succumb to apoptosis. Mitochondrial changes appear to be the enforcing factor for this process. The Transformation--Normalizing-redifferentiation--Apoptosis sequence has been shown by several studies, utilizing various cell types, apoptotic inducers, biomarkers and time frames. Although some studies have shown concomitant apoptosis and redifferentiation, others have reported apoptosis without prior redifferentiation. However, utilizing the appropriate time frame and the markers of earlier mitochondrial changes, one would detect a scenario similar to the retinoid model. This situation can be achieved by delaying apoptosis or reducing the inducer concentration in such systems. The final physiological fate of a normal terminally differentiated cells is apoptosis. Similarly, it is suggested that a degree of normalizing redifferentiation of transformed cells might be expected prior to apoptosis. The former seemed obligatory at least in the retinoid-pancreatic model.

Gas exchange threshold as a predictor of severe postoperative complications after lung resection in mild-to-moderate chronic obstructive pulmonary disease.

Low exercise capacity is considered predictive for postoperative complications or death after thoracic and general surgery. However, in recent literature no agreement has been found about the predictive cut-off values for preoperative exercise parameters. The aim of this work was to investigate whether peak oxygen consumption (V'o2) and noninvasive anaerobic threshold (AT) determined by gas exchange threshold (GET) can be reliable preoperative predictors of mortality and morbidity after lung resection in patients with mild-to-moderate (forced expiratory volume in one second (FEV1) > 50% predicted) chronic obstructive pulmonary disease (COPD). Fifty tour COPD patients were studied before lung surgery: 12 had severe complications, 16 had mild and 26 had no complications. Peak V'O2 sensitivity and specificity in predicting severe postoperative complications were 41.6% and 95.5% respectively (using 75% of the predicted value as cut-off), while for GET they were 91.6% and 97.6% respectively (using 14.5 mL.kg-1.min-1 as cut-off value). Only one patient (3.5%) with a peak V'O2 > 20 mL.kg-1.min-1 suffered severe complications. On the other hand 11 out of the 26 patients (42.3%) with peak V'O2 < 20 mL.kg-1.min-1 had serve complications. In patients with peak V'O2 < 20 mL.kg-1.min-1, 11 out of 12 (91.6%) with a GET < or = 14.5 mL.kg-1.min-1 suffered severe complications, whereas 15 out of 15 (100%) with a GET > 14.5 mL.kg-1.min-1 showed no or mild complications. In conclusion, peak oxygen consumption values > 20 mL.kg-1.min-1 can be considered a safe upper cut-off limit for pulmonary resection. In patients with a peak oxygen consumption value < 20 mL.kg-1.min-1, gas exchange threshold determination can improve significantly the predictivity of a cardiopulmonary test for severe complications and must be routinely considered.