100 research outputs found

    Studies of the inner shelf and coastal sedimentation environment of the Beaufort Sea from ERTS-A

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    The author has identified the following significant results. Shearing periodically occurs between the westward moving pack ice (3 to 10 km/d) within the Pacific Gyre and the fast ice along the coast, forming major grounded shear and pressure ridges between the 10 to 40 m isobaths. Ridges occur in patterns conforming to known shoals. The zone of grounded ridges, called stamukhi zone, protects the inner shelf and coast from marine energy and pack ice forces. Relatively undeformed fast ice grows inshore of the stamukhi zone. The boundary is explained in terms of pack ice drift and major promontories and shoals. Intense ice gaging, highly disrupted sediments, and landward migration of shoals suggest that much of the available marine energy is expended on the sea floor within the stamukhi zone. Naleds (products of river icings) on the North Slope are more abundant east than west of the Colville River. Their location, growth, and decay were studied from LANDSAT imagery

    Optimization of copper nanocones for field emission cathodes

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    Gut microbiota, diet, and chronic diseases: the role played by oxidative stress

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    The authors gratefully acknowledge the Espirito Santo Research Foundation (FAPES) (Grant CNPq/FAPES No. 24/2018; Termo Outorga 569/2018) and the Brazilian National Council for Research and Development (CNPq) (CNPq Grant Bolsa Produtividade 2015-2019) for the financial support to our research projectS

    Surface Plasmons in Conductively Coupled Nanowire Dimers

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    Crambescin C1 Acts as A Possible Substrate of iNOS and eNOS Increasing Nitric Oxide Production and Inducing In Vivo Hypotensive Effect

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    Crambescins are guanidine alkaloids from the sponge Crambe crambe. Crambescin C1 (CC) induces metallothionein genes and nitric oxide (NO) is one of the triggers. We studied and compared the in vitro, in vivo, and in silico effects of some crambescine A and C analogs. HepG2 gene expression was analyzed using microarrays. Vasodilation was studied in rat aortic rings. In vivo hypotensive effect was directly measured in anesthetized rats. The targets of crambescines were studied in silico. CC and homo-crambescine C1 (HCC), but not crambescine A1 (CA), induced metallothioneins transcripts. CC increased NO production in HepG2 cells. In isolated rat aortic rings, CC and HCC induced an endothelium-dependent relaxation related to eNOS activation and an endothelium-independent relaxation related to iNOS activation, hence both compounds increase NO and reduce vascular tone. In silico analysis also points to eNOS and iNOS as targets of Crambescin C1 and source of NO increment. CC effect is mediated through crambescin binding to the active site of eNOS and iNOS. CC docking studies in iNOS and eNOS active site revealed hydrogen bonding of the hydroxylated chain with residues Glu377 and Glu361, involved in the substrate recognition, and explains its higher binding affinity than CA. The later interaction and the extra polar contacts with its pyrimidine moiety, absent in the endogenous substrate, explain its role as exogenous substrate of NOSs and NO production. Our results suggest that CC serve as a basis to develop new useful drugs when bioavailability of NO is perturbed.Fil: Rubiolo, Juan Andrés. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Ministerio de Ciencia, Tecnologia E Innovacion Productiva (santa Fe). - Gobierno de la Provincia de Santa Fe. Ministerio de Ciencia, Tecnologia E Innovacion Productiva (santa Fe).; Argentina. Universidad de Santiago de Compostela; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Lence, Emilio. Universidad de Santiago de Compostela; EspañaFil: González Bello, Concepción. Universidad de Santiago de Compostela; EspañaFil: Roel, María. Universidad de Santiago de Compostela; EspañaFil: Gil Longo, José. Universidad de Santiago de Compostela; EspañaFil: Campos Toimil, Manuel. Universidad de Santiago de Compostela; EspañaFil: Ternon, Eva. Université Nice Sophia Antipolis. Laboratoire Jean-alexandre Dieudonné.; FranciaFil: Thomas, Olivier P.. National University of Ireland Galway; IrlandaFil: González Cantalapiedra, Antonio. Universidad de Santiago de Compostela; EspañaFil: López Alonso, Henar. Universidad de Santiago de Compostela; EspañaFil: Vieytes, Mercedes R.. Universidad de Santiago de Compostela; EspañaFil: Botana, Luis M.. Universidad de Santiago de Compostela; Españ

    Direct Observation of Propagating Gigahertz Coherent Guided Acoustic Phonons in Free Standing Single Copper Nanowires

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    We report on gigahertz acoustic phonon waveguiding in free-standing single copper nanowires studied by femtosecond transient reflectivity measurements. The results are discussed on the basis of the semianalytical resolution of the Pochhammer and Chree equation. The spreading of the generated Gaussian wave packet of two different modes is derived analytically and compared with the observed oscillations of the sample reflectivity. These experiments provide a unique way to independently obtain geometrical and material characterization. This direct observation of coherent guided acoustic phonons in a single nano-object is also the first step toward nanolateral size acoustic transducer and comprehensive studies of the thermal properties of nanowires

    Sequential Deposition Of Multisegment Nanowires

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    Electrochemical replication of nanoporous membranes represents a facile approach towards the fabrication of nanostructures with tailored properties. By the template method we prepared multisegment nanowires with tailored structure. The first step of the process was the fabrication of the nanoporous template by swift heavy ion irradiation and subsequent selective etching of the ion track. The next step was to fill the pores with the desired combination of materials. In this manner, by sequential electrodeposition steps of metal and semiconductor we prepared Ni -CdTe and Ni -ZnO -Ni nanowires

    Climate change-driven coastal erosion modelling in temperate sandy beaches: Methods and uncertainty treatment

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    Developing future projections of shoreline change requires a good understanding of the driving coastal processes. These processes result primarily from the combination of mean sea level, waves, storm surges and tides, which are affected by global and regional climate change, and whose uncertainty increases with time. This paper reviews the current state of the art of methods used to model climate change-induced coastal erosion focusing on how climate change-related drivers and the associated uncertainty are considered. We identify research gaps, describe and analyse the key components of a comprehensive framework to derive future estimates of shoreline change and make suggestions for good practice. Within the scope of the review, we find that although significant progress has been made over the last decade, most of the studies limit uncertainty sampling to considering ranges of variation of forcing variables and ensembles of emissions scenarios, and applications with high level of probabilistic development remain few. Further research is necessary to fully (a) incorporate projected time series of coastal drivers into the erosion models, including bias correction; (b) sufficiently sample the uncertainty associated with each step of the top-down approach, including the consideration of different emission scenarios, inter- and intra-model variability, and multiple runs of erosion models or model ensembles; and (c) reduce uncertainty in shoreline change estimates by developing better datasets and model parameterisations, and progressing in detection and attribution

    Mechanisms of Action of Kefir in Chronic Cardiovascular and Metabolic Diseases

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    The gut microbiota maintains a complex mutual interaction with different organs of the host. Whereas in normal conditions this natural community of trillions of microorganisms greatly contributes to the human health, gut dysbiosis is related with onset or worsening of diverse chronic systemic diseases. Thus, the reestablishment of gut microbiota homeostasis with consumption of prebiotics and probiotics may be a relevant strategy to prevent or attenuate several cardiovascular and metabolic complications. Among these functional foods, the synbiotic kefir, which is a fermented milk composed of a mixture of bacteria and yeasts, is currently the most used and has attracted the attention of health care professionals. The present review is focused on reports describing the feasibility of kefir consumption to provide benefits in cardiometabolic diseases, including hypertension, vascular endothelial dysfunction, dyslipidemia and insulin resistance. Interestingly, recent studies show that mechanisms of actions of kefir in cardiometabolic diseases include recruitment of endothelial progenitor cells, improvement of the balance vagal/sympathetic nervous system, diminution of excessive generation of reactive oxygen species, angiotensin converting enzyme inhibition, anti-inflammatory cytokines profile and alteration of the intestinal microbiota. These findings provide a better understanding about the mechanisms of the beneficial actions of kefir and motivate further investigations to determine whether the use of this synbiotic could also be translated into clinical improvements in cardiometabolic diseases
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