294 research outputs found

    Glacial dynamics in pre-Alpine narrow valleys during the Last Glacial Maximum inferred by lowland fluvial records (northeast Italy)

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    During the Last Glacial Maximum (LGM), most of the major glaciated basins of the European Southern Alps had piedmont lobes with large outwash plains; only a few glaciers remained within the valley. Piedmont glaciers have left well-preserved terminal moraines, which allow for investigations to be carried out and inferences to be made regarding their evolution and chronology. Valley glaciers\u2019 remnants, on the contrary, are often scantly preserved, and changes can only be detected through correlations with glaciofluvial deposits in downstream alluvial basins. The Brenta glacial system\u2019s dynamics in the glacier\u2019s terminal tract have been inferred through a wide range of sediment analysis techniques on an alluvial stratigraphic record of the Brenta megafan (northeast Italy), and via the mapping of in-valley glacial/glaciofluvial remnants. Glaciers flowing across narrow gorges could possibly be slowed/blocked by such morphology, and glacial/sediment fluxes may then be diverted to lateral valleys. Moreover, narrow valleys may induce glaciers to bulge and form icefalls at their front, preventing the formation of terminal moraines. The Brenta Glacier was probably slowed/blocked by the narrow Valsugana Gorge downstream of Primolano and was effectively diverted eastwards across a wind gap (Canal La Menor Valley), joining the Cismon/Piave glaciers near Rocca and ending 2 km downstream. The Cismon and Piave catchments started to contribute to the Brenta system just after 27 ka cal BP until at least 19:5 ka cal BP. After the glaciers collapsed, the Piave River once again flowed into its main valley, whilst the Cismon continued to merge with the Brenta. This investigation shows that glacial catchments may vary significantly over time during a single glaciation in rugged Alpine terrains. Sand petrography and the chemical/mineralogical composition of sediments are powerful proxies for tracing such variations, as they propagate through the glacial and glaciofluvial systems and can be recognized in the alluvial stratigraphic record far downstream from the glacier front

    Metal abundances in extremely distant Galactic old open clusters. II. Berkeley 22 and Berkeley 66

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    We report on high resolution spectroscopy of four giant stars in the Galactic old open clusters Berkeley~22 and Berkeley~66 obtained with HIRES at the Keck telescope. We find that [Fe/H]=0.32±0.19[Fe/H]=-0.32\pm0.19 and [Fe/H]=0.48±0.24[Fe/H]=-0.48\pm0.24 for Berkeley~22 and Berkeley~66, respectively. Based on these data, we first revise the fundamental parameters of the clusters, and then discuss them in the context of the Galactic disk radial abundance gradient. We found that both clusters nicely obey the most updated estimate of the slope of the gradient from \citet{fri02} and are genuine Galactic disk objects.Comment: 20 pages, 6 eps figures, accepted for publication in the Astronomical Journa

    Energy-efficient autonomous solar water-pumping system for permanent-magnet synchronous motors

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    This paper presents a novel stand–alone solar– powered water pumping system, especially suited for usage in rural or remote areas. The system is primarily designed to reduce both cost and complexity, while simultaneously guaranteeing opti¬mal utilisation of the photovoltaic generator. The use of standard hardware and control architectures ensures ease of installation, service and maintenance. The proposed solution consists of a water pump driven by a permanent magnet synchronous motor (PMSM), controlled by a conventional field oriented control scheme. The photovoltaic array is directly connected to the DC bus of the inverter, with no intermediate power conversion stages. A perturbation based extremum–seeking controller adjusts the motor speed reference to attain the maximum power point opera-tion of the photovoltaic array. Both simulations and experimental results on a full-scale prototype support the effectiveness of the proposed system

    Ozonation of Human Blood Induces a Remarkable Upregulation of Heme Oxygenase-1 and Heat Stress Protein-70

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    Heme oxygenase-I (HO-1) has emerged as one of the most protective enzymes and its pleiotropic activities have been demonstrated in a variety of human pathologies. Unpublished observations have shown that HO-1 is induced after the infusion of ozonated blood into the respective donors, and many other experimental observations have demonstrated the efficacy of oxidizing agents. It appeared worthwhile to evaluate whether we could better define the activity of potential inducers such as hydrogen peroxide and ozonated human plasma. Human vascular endothelial cells at confluence were challenged with different concentrations of these inducers and the simultaneous production of nitric oxide (NO); and HO-1 was measured by either measuring nitrite, or bilirubin formation, or/and the immune reactivity of the protein by Western blot using a rabbit antihuman HO-1 and Hsp-70. The results show that production of both NO and HO-1 is fairly dose dependent but is particularly elevated using human plasma after transient exposure to a medium ozone concentration. At this concentration, there is also induction of Hsp-70. The results clarify another positive effect achievable by the use of ozone therapy

    Interleukin-1 β

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    Inflammation and tumor hypoxia are intimately linked and breast cancer provides a typical example of an inflammation-linked malignant disease. Indeed, breast cancer progression is actively supported by inflammatory components, including IL-1 beta, and by the hypoxia-inducible factor- (HIF-) 1 alpha In spite of many attempts where the role of either IL-1 beta or HIF-1 beta was evaluated, detailed mechanisms for their effects on breast cancer cell migration under hypoxia are still unclear. We here report that IL-1 beta increased MDAMB231 cell migration under hypoxic conditions along with HIF-1 alpha accumulation and upregulation of CXCR1, which is transcriptionally regulated by HIF-1 alpha, as well as an increased expression of CXCL8 and NF kappa B. In addition, IL-1 beta-induced cell migration in hypoxia was not affected when HIF-1 alpha was inhibited by either siRNA or Topotecan, well known for its inhibitory effect on HIF-1 alpha Of interest, HIF-1 alpha inhibition did not reduce NF kappa B and CXCL8 expression and the reduction of IL-1 beta-induced cell migration under hypoxia was achieved only by pharmacological inhibition of NF kappa B. Our findings indicate that inhibition of HIF-1 alpha does not prevent the migratory program activated by IL-1 beta in hypoxic MDAMB231 cells. They also suggest a potential compensatory role of NF kappa B/CXCL8 pathway in IL-1 beta-induced MDAMB231 cell migration in a hypoxic microenvironment

    Quantitative Spectroscopy of Blue Supergiants in Metal-Poor Dwarf Galaxy NGC 3109

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    We present a quantitative analysis of the low-resolution (4.5 A) spectra of 12 late-B and early-A blue supergiants (BSGs) in the metal-poor dwarf galaxy NGC 3109. A modified method of analysis is presented which does not require use of the Balmer jump as an independent temperature indicator, as used in previous studies. We determine stellar effective temperatures, gravities, metallicities, reddening, and luminosities, and combine our sample with the early-B type BSGs analyzed by Evans et al. (2007) to derive the distance to NGC 3109 using the Flux-weighted Gravity-Luminosity Relation (FGLR). Using primarily Fe-group elements, we find an average metallicity of [Z] = -0.67 +/- 0.13, and no evidence of a metallicity gradient in the galaxy. Our metallicities are higher than those found by Evans et al. (2007) based on the oxygen abundances of early-B supergiants ([Z] = -0.93 +/- 0.07), suggesting a low alpha/Fe ratio for the galaxy. We adjust the position of NGC 3109 on the BSG-determined galaxy mass-metallicity relation accordingly and compare it to metallicity studies of HII regions in star-forming galaxies. We derive an FGLR distance modulus of 25.55 +/- 0.09 (1.27 Mpc) that compares well with Cepheid and tip of the red giant branch (TRGB) distances. The FGLR itself is consistent with those found in other galaxies, demonstrating the reliability of this method as a measure of extragalactic distances.Comment: 50 pages, 23 figures; Accepted for publication in The Astrophysical Journa

    The p50 NF-\u3baB subunit is a prognostic regulator of colorectal cancer-associated inflammation

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    In most tumors, tumor associated macrophages (TAMs) express an M2-skewed phenotype and are therefore associated with unfavorable prognosis. However, the impact of TAMs in colorectal cancer (CRC) development and outcome is still controversial. We first demonstrate, by parallel studies in colitis-associated cancer (CAC) and in genetically driven ApcMin mouse models, that p50 NF-\u3baB is essential for CRC development by restraining M1-dependent antitumor response. In absence of p50 mice developed fewer and smaller CRC lesions which express enhanced levels of M1/Th1 cytokines/chemokines including IL-12 and CXCL10, whose administration restrained CAC development in vivo. Moreover colons from p50-/- tumor bearers showed a reduced number of TAMs, as opposed to increased NK, NKT, CD8+ T cells and apoptotic cancer cells. Consistently, in CRC patients, high burden of p50+ TAMs was associated with decreased M1/Th1 inflammation and worse outcome indicating p50 as a new candidate for prognostic and target therapeutic intervention

    Chemometric-assisted cocrystallization: Supervised pattern recognition for predicting the formation of new functional cocrystals

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    Owing to the antimicrobial and insecticide properties, the use of natural compounds like essential oils and their active components has proven to be an effective alternative to synthetic chemicals in different fields ranging from drug delivery to agriculture and from nutrition to food preservation. Their limited application due to the high volatility and scarce water solubility can be expanded by using crystal engineering approaches to tune some properties of the active molecule by combining it with a suitable partner molecule (coformer). However, the selection of coformers and the experimental effort required for discovering cocrystals are the bottleneck of cocrystal engineering. This study explores the use of chemometrics to aid the discovery of cocrystals of active ingredients suitable for various applications. Partial Least Squares–Discriminant Analysis is used to discern cocrystals from binary mixtures based on the molecular features of the coformers. For the first time, by including failed cocrystallization data and considering a variety of chemically diverse compounds, the proposed method resulted in a successful prediction rate of 85% for the test set in the model validation phase and of 74% for the external test set
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