ALBERT

Description: The synthesis, characterisation and evaluation of the in vitro cytotoxicity of four indole-based half-sandwich metal complexes towards two ovarian cancer cell lines (A2780 and A2780cisR) and one normal prostate cell line (PNT2) are presented herein. Although capable of inducing catalytic oxidation of NADH and able to reduce NAD+ with high turnover frequencies, in cells and in the presence of sodium formate, these complexes also strongly interact with biomolecules such as glutathione. This work highlights that efficient out-of-cells catalytic activity might lead to higher reactivity towards biomolecules, thus inhibiting the in-cells catalytic processes.

Description: Nitrogen is the main constituent of the Earth's atmosphere, but its provenance in the Earth's mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth's accretion versus that subducted from the Earth's surface is unclear1-6. Here we show that the mantle may have retained remnants of such primordial nitrogen. We use the rare 15N15N isotopologue of N2 as a new tracer of air contamination in volcanic gas effusions. By constraining air contamination in gases from Iceland, Eifel (Germany) and Yellowstone (USA), we derive estimates of mantle δ15N (the fractional difference in 15N/14N from air), N2/36Ar and N2/3He. Our results show that negative δ15N values observed in gases, previously regarded as indicating a mantle origin for nitrogen7-10, in fact represent dominantly air-derived N2 that experienced 15N/14N fractionation in hydrothermal systems. Using two-component mixing models to correct for this effect, the 15N15N data allow extrapolations that characterize mantle endmember δ15N, N2/36Ar and N2/3He values. We show that the Eifel region has slightly increased δ15N and N2/36Ar values relative to estimates for the convective mantle provided by mid-ocean-ridge basalts11, consistent with subducted nitrogen being added to the mantle source. In contrast, we find that whereas the Yellowstone plume has δ15N values substantially greater than that of the convective mantle, resembling surface components12-15, its N2/36Ar and N2/3He ratios are indistinguishable from those of the convective mantle. This observation raises the possibility that the plume hosts a primordial component. We provide a test of the subduction hypothesis with a two-box model, describing the evolution of mantle and surface nitrogen through geological time. We show that the effect of subduction on the deep nitrogen cycle may be less important than has been suggested by previous investigations. We propose instead that high mid-ocean-ridge basalt and plume δ15N values may both be dominantly primordial features.

Description: Published

Description: 367–371

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: JCR Journal

Description: We present two models using monitoring data in the production of volcanic eruption forecasts. The first model enhances the well-established failure forecast method introducing an SDE in its formulation. In particular, we developed new method for performing short-term eruption timing probability forecasts, when the eruption onset is well represented by a model of a significant rupture of materials. The method enhances the well-known failure forecast method equation. We allow random excursions from the classical solutions. This provides probabilistic forecasts instead of deterministic predictions, giving the user critical insight into a range of failure or eruption dates. Using the new method, we describe an assessment of failure time on present-day unrest signals at Campi Flegrei caldera (Italy) using either seismic count and ground deformation data. The new formulation enables the estimation on decade-long time windows of data, locally including the effects of variable dynamics. The second model establishes a simple method to update prior vent opening spatial maps. The prior reproduces the two-dimensional distribution of past vent distribution with a Gaussian Field. The likelihood relies on a one-dimensional variable characterizing the chance of material failure locally, based, for instance, on the horizontal ground deformation. In other terms, we introduce a new framework for performing short-term eruption spatial forecasts by assimilating monitoring signals into a prior (“background”) vent opening map. To describe the new approach, first we summarize the uncertainty affecting a vent opening map pdf of Campi Flegrei by defining an appropriate Gaussian random field that replicates it. Then we define a new interpolation method based on multiple points of central symmetry, and we apply it on discrete GPS data. Finally, we describe an application of the Bayes’ theorem that combines the prior vent opening map and the data-based likelihood product-wise. We provide examples based on either seismic count and interpolated ground deformation data collected in the Campi Flegrei volcanic area.

Description: Published

Description: San Francisco

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: Identifying the origin of noble gases in Earth's mantle can provide crucial constraints on the source and timing of volatile (C, N, H2O, noble gases, etc.) delivery to Earth. It remains unclear whether the early Earth was able to directly capture and retain volatiles throughout accretion or whether it accreted anhydrously and subsequently acquired volatiles through later additions of chondritic material. Here, we report high-precision noble gas isotopic data from volcanic gases emanating from, in and around, the Yellowstone caldera (Wyoming, United States). We show that the He and Ne isotopic and elemental signatures of the Yellowstone gas requires an input from an undegassed mantle plume. Coupled with the distinct ratio of 129Xe to primordial Xe isotopes in Yellowstone compared with mid-ocean ridge basalt (MORB) samples, this confirms that the deep plume and shallow MORB mantles have remained distinct from one another for the majority of Earth's history. Krypton and xenon isotopes in the Yellowstone mantle plume are found to be chondritic in origin, similar to the MORB source mantle. This is in contrast with the origin of neon in the mantle, which exhibits an isotopic dichotomy between solar plume and chondritic MORB mantle sources. The co-occurrence of solar and chondritic noble gases in the deep mantle is thought to reflect the heterogeneous nature of Earth's volatile accretion during the lifetime of the protosolar nebula. It notably implies that the Earth was able to retain its chondritic volatiles since its earliest stages of accretion, and not only through late additions.

Description: Published

Description: 13997–14004

Description: 3V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcanici

Description: JCR Journal

Description: We present two models using precursory information in the production of volcanic eruption forecasts. The first model enhances the well-established failure forecast method introducing an SDE in its formulation. The second model establishes a simple method to update prior spatial maps. The prior reproduce the two-dimensional distribution of past activity with a Gaussian Field. The likelihood relies on a one-dimensional variable characterizing the chance of material failure locally, based on the horizontal ground deformation.

Description: Published

Description: Valencia

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: We introduce a doubly stochastic method for performing material failure theory based forecasts of volcanic eruptions. The method enhances the well known Failure Forecast Method equation, introducing a new formulation similar to the Hull-White model in financial mathematics. In particular, we incorporate a stochastic noise term in the original equation, and systematically characterize the uncertainty. The model is a stochastic differential equation with mean reverting paths, where the traditional ordinary differential equation defines the mean solution. Our implementation allows the model to make excursions from the classical solutions, by including uncertainty in the estimation. The doubly stochastic formulation is particularly powerful, in that it provides a complete posterior probability distribution, allowing users to determine a worst case scenario with a specified level of confidence. We apply the new method on historical datasets of precursory signals, across a wide range of possible values of convexity in the solutions and amounts of scattering in the observations. The results show the increased forecasting skill of the doubly stochastic formulation of the equations if compared to statistical regression.

Description: Published

Description: Article 135

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: The Ancestral South Sandwich Arc (ASSA) has a short life-span of c. 20. m.y. (early Oligocene to middle-late Miocene) before slab retreat and subsequent 'resurrection' as the active South Sandwich Island Arc (SSIA). The ASSA is, however, significant because it straddled the eastern margin of the Drake Passage Gateway where it formed a potential barrier to deep ocean water and mantle flow from the Pacific to Atlantic. The ASSA may be divided into three parts, from north to south: the Central Scotia Sea (CSS), the Discovery segment, and the Jane segment. Published age data coupled with new geochemical data (major elements, trace elements, Hf-Nd-Sr-Pb isotopes) from the three ASSA segments place constraints on models for the evolution of the arc and hence gateway development. The CSS segment has two known periods of activity. The older, Oligocene, period produced basic-acidic, mostly calc-alkaline rocks, best explained in terms of subduction initiation volcanism of Andean-type (no slab rollback). The younger, middle-late Miocene period produced basic-acidic, high-K calc-alkaline rocks (lavas and pyroclastic rocks with abundant volcanigenic sediments) which, despite being erupted on oceanic crust, have continental arc characteristics best explained in terms of a large, hot subduction flux most typical of a syn- or post-collision arc setting. Early-middle Miocene volcanism in the Discovery and Jane arc segments is geochemically quite different, being typically tholeiitic and compositionally similar to many lavas from the active South Sandwich Island Arc front. There is indirect evidence for Western Pacific-type (slab rollback) subduction initiation in the southern part of the ASSA and for the back-arc basins (the Jane and Scan Basins) to have been active at the time of arc volcanism. Models for the death of the ASSA in the south following a series of ridge-trench collisions are not positively supported by any geochemical evidence of hot subduction, but cessation of subduction by approach of progressively more buoyant oceanic lithosphere is consistent with both geochemistry and geodynamics. In terms of deep ocean water flow the early stages of spreading at the East Scotia Ridge (starting at 17-15. Ma) may have been important in breaking up the ASSA barrier while the subsequent establishment of a STEP (Subduction-Transform Edge Propagator) fault east of the South Georgia microcontinent (〈. 11. Ma) led to formation of the South Georgia Passage used by the Antarctic Circumpolar Current today. In terms of mantle flow, the subduction zone and arc root likely acted as a barrier to mantle flow in the CSS arc segment such that the ASSA itself became the Pacific-South Atlantic mantle domain boundary. This was not the case in the Discovery and Jane arc segments, however, because the northward flow of the South Atlantic mantle behind the southern part of the ASSA gave an Atlantic provenance to the whole southern ASSA.

Description: Published

Description: E-cadherin is a tumor suppressor protein, and the loss of its expression in association with the epithelial mesenchymal transition (EMT) occurs frequently during tumor metastasis. However, many metastases continue to express E-cadherin, and a full EMT is not always necessary for metastasis; also, positive roles for E-cadherin expression in metastasis have been reported. We hypothesize instead that changes in the functional activity of E-cadherin expressed on tumor cells in response to environmental factors is an important determinant of the ability of the tumor cells to metastasize. We find that E-cadherin expression persists in metastatic lung nodules and circulating tumor cells (CTCs) in two mouse models of mammary cancer: genetically modified MMTV-PyMT mice and orthotopically grafted 4T1 tumor cells. Importantly, monoclonal antibodies that bind to and activate E-cadherin at the cell surface reduce lung metastasis from endogenous genetically driven tumors and from tumor cell grafts. E-cadherin activation inhibits metastasis at multiple stages, including the accumulation of CTCs from the primary tumor and the extravasation of tumor cells from the vasculature. These activating mAbs increase cell adhesion and reduce cell invasion and migration in both cell culture and three-dimensional spheroids grown from primary tumors. Moreover, activating mAbs increased the frequency of apoptotic cells without affecting proliferation. Although the growth of the primary tumors was unaffected by activating mAbs, CTCs and tumor cells in metastatic nodules exhibited increased apoptosis. Thus, the functional state of E-cadherin is an important determinant of metastatic potential beyond whether the gene is expressed.