The connecting tubule (CNT) of superficial nephrons comes into close contact with the corresponding afferent arteriole of its own glomerulus. Ren et al. demonstrate that this close anatomical ...configuration is also the site for cross-talk between the CNT and the afferent arteriole. This mechanism is triggered by the entry of sodium through amiloride sodium channels and may antagonize tubuloglomerular feedback.
Knowledge of the in situ stress state in rock and soil deposits is very important in many problems in civil, mining and petroleum engineering and energy development, as well as in geology and ...geophysics. The prediction of the response of rock masses interacting with underground structures is highly influenced by the stress field. For example, as pointed out in 1, in civil and mining engineering, in situ stresses control the distribution and magnitude of the stresses around underground openings such as tunnels, mines, shaft or caverns. Stress concentrations in the excavation walls may be large enough to overstress the rock, mobilize the strength of the rock mass and induce failure. On the other hand, tensile stresses in excavation walls may open existing fractures or create new ones which could result in block stability problems.
The La Fossa volcano on the Island of Vulcano, Italy, showed signs of more energetic fumarolic–solfataric activity during 2021. Several increases in volcanic gas emissions and seismicity, namely, ...“crisis,” punctuated the passive degassing at Vulcano that had ensued after the last 1888–1890 vulcanian eruption. Most of the gases (i.e., up to 90%) were emitted at the crater cone while the diffuse degassing of CO2 at Vulcano Porto accounted for more than 10% of the volcanic emissions. Two anomalous degassing zones at the base of the volcanic cone (i.e., Palizzi and Faraglione) showed notable changes in the gas output during the volcanic crisis. In these zones, increases of soil CO2 flux (φCO2) had several practical implications other than of volcanological interest, owing to the risk related to people's exposure to volcanic gas emissions. The results of this study reveal variations of the average φCO2 from 74 g m−2 d−1 during September 2021 to 370 g m−2 d−1 in November 2021, which were 27% and 538% higher than the statistical background since 1988 (φCO2 ≈ 58 g m−2 d−1), respectively. These observations helped in volcanic surveillance at Vulcano. The soil CO2 partitioning determined using both φCO2 and carbon isotope measurements, helped track changes in the volcanic CO2 output from 9.97 · 104 to 101.15 · 104 kg d−1. Estimates for volcanic CO2 suggest that the instability of a magmatic body caused a transition from background fumarolic–solfataric activity toward an unrest event after September 2021.
Plain Language Summary
A noticeable increase in volcanic outgassing occurred at Vulcano, Italy, in 2021. Although the volcano has not achieved critical conditions to produce an eruption, the soil CO2 emissions have prevented access into some zones of the island, due to the volcanic risk known as the gas hazard. Specialized instruments such as fluxmeters and spectrophotometers were used to measure the soil CO2 flux and the carbon isotopes of CO2 during four soil gas surveys. To understand why the volcanic system evolved toward a period of unrest, we modeled our measurements using mass balance calculations. We find that the CO2 increase, almost 10 times its baseline, was most likely due to the instability of a magmatic body within the mantle to crustal boundary known as the Moho discontinuity. Because of this magmatic instability, the volcanic CO2 emissions resumed in some zones of the island where volcanic activity had been dormant for decades. The resumption of volcanic degassing in a short period had not been recorded before at Vulcano, and it is important to understand its cause because future changes in magmatic activity might produce larger CO2 emissions that will have the added risk of gas hazards as well as that of an explosion.
Key Points
Diffuse degassing surveys help track transition toward volcanic unrest periods
Carbon isotope composition allows quantification of the volcanic CO2 emitted by soils
Significant changes in volcanic outgassing state caused increases in soil CO2 emissions and gas hazard at Vulcano—Italy—during 2021
Some classes of bone fractures are routinely stabilized and aligned by the use of intramedullary nails. The identification of the pose, i.e., the position and the orientation of the drill holes ...hidden by a bone and the tissue is currently obtained by X-ray with all the well-known disadvantages of this technology. The idea of substituting this methodology with an eddy-current-based one has been explored in the previous work, but, in spite of interesting features, the developed technique suffered from some shortcomings. In this paper, we propose a novel technique that is very computationally efficient and provides real-time identification performance.
On February 27, 2007 a new eruption started at Stromboli that lasted until April 2 and included a paroxysmal explosion on March 15. Geochemical monitoring carried out over several years revealed some ...appreciable variations that preceded both the eruption onset and the explosion. The carbon dioxide (CO
2) flux from the soil at Pizzo Sopra La Fossa markedly increased a few days before the eruption onset, and continued during lava effusion to reach its maximum value (at 90,000 g m
−
2
d
−
1
) a few days before the paroxysm. Almost contemporarily, the
δ
13C
CO
2
of the SC5 fumarole located in the summit area increased markedly, peaking just before the explosion (
δ
13C
CO
2
~
−
1.8‰). Following the paroxysm, helium (He) isotopes measured in the gases dissolved in the basal thermal aquifer sharply increased. Almost contemporarily, the automatic station of CO
2 flux recorded an anomalous degassing rate. Also temperatures and the vertical thermal gradient, which had been measured since November 2006 in the soil at Pizzo Sopra La Fossa, showed appreciable variabilities that lasted until the end of the eruption. The geochemical variations indicated the degassing of a new batch of volatile-rich magma that preceded and probably fed the paroxysm. The anomalous
3He/
4He ratio suggested that the ascent of a second batch of volatile-rich magma toward the surface was probably responsible of the resumption of the ordinary activity. A comparison with the geochemical variations observed during the 2002–2003 eruption indicated that the 2007 eruption was less energetic.
Transforming growth factor β (TGF-β ) has been shown to participate in the pathophysiology of diabetic complications. As shown most recently, TGF-β stimulates the expression of a distinct ...serine/threonine kinase (hSGK) which had previously been cloned as an early gene transcriptionally regulated by cell volume alterations. The present study was performed to elucidate transcription and function of hSGK in diabetic nephropathy. As shown by Northern blotting, an increase of extracellular glucose concentration increased hSGK mRNA levels in cultured cells, an effect qualitatively mimicked by osmotic cell shrinkage or treatment with TGF-β (2 μ g/liter), phorbol 12,13-didecanoate (1 μ M), or the Ca2+ionophore ionomycin (1 μ M) and blunted by high concentrations of nifedipine (10 and 100 μ M). In situ hybridization revealed that hSGK transcription was markedly enhanced in diabetic nephropathy, with particularly high expression in mesangial cells, interstitial cells, and cells in thick ascending limbs of Henle's loop and distal tubules. According to voltage clamp and tracer flux studies in Xenopus oocytes expressing the renal epithelial Na+channel ENaC or the mouse thick ascending limb Na+,K+,2Cl-cotransporter BSC-1, coexpression with hSGK stimulated ENaC and BSC-1 11-fold and 6-fold, respectively, effects reversed by kinase inhibitors staurosporine (1 μ M) and chelerythrine (1 μ M) and not elicited by inactive hSGK. In conclusion, excessive extracellular glucose concentrations enhance hSGK transcription, which in turn stimulates renal tubular Na+transport. These observations disclose an additional element in the pathophysiology of diabetic nephropathy.
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