788 research outputs found

    Caffeine Inhibits EGF-Stimulated Trophoblast Cell Motility through the Inhibition of mTORC2 and Akt.

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    Impaired trophoblast invasion is associated with pregnancy disorders such as early pregnancy loss and preeclampsia. There is evidence to suggest that the consumption of caffeine during pregnancy may increase the risk of pregnancy loss; however, little is known about the direct effect of caffeine on normal trophoblast biology. Our objectives were to examine the effect of caffeine on trophoblast migration and motility after stimulation with epidermal growth factor (EGF) and to investigate the intracellular signaling pathways involved in this process. Primary first-trimester extravillous trophoblasts (EVT) and the EVT-derived cell line SGHPL-4 were used to study the effect of caffeine on EGF-stimulated cellular motility using time-lapse microscopy. SGHPL-4 cells were further used to study the effect of caffeine and cAMP on EGF-stimulated invasion of fibrin gels. The influence of caffeine and cAMP on EGF-stimulated intracellular signaling pathways leading to the activation of Akt were investigated by Western blot analysis. Caffeine inhibits both EGF-stimulated primary EVT and SGHPL-4 cell motility. EGF stimulation activates phosphatidylinositol 3-kinase, and Akt and caffeine inhibit this activation. Although cAMP inhibits both motility and invasion, it does not inhibit the activation of Akt, indicating that the effects of caffeine seen in this study are independent of cAMP. Further investigation indicated a role for mammalian target of rapamycin complex 2 (mTORC2) as a target for the inhibitory effect of caffeine. In conclusion, we demonstrate that caffeine inhibits EGF-stimulated trophoblast invasion and motility in vitro and so could adversely influence trophoblast biology in vivo

    Using 14C and 3H to understand groundwater flow and recharge in an aquifer window

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    Knowledge of groundwater residence times and recharge locations is vital to the sustainable management of groundwater resources. Here we investigate groundwater residence times and patterns of recharge in the Gellibrand Valley, southeast Australia, where outcropping aquifer sediments of the Eastern View Formation form an "aquifer window" that may receive diffuse recharge from rainfall and recharge from the Gellibrand River. To determine recharge patterns and groundwater flow paths, environmental isotopes (3H, 14C, δ13C, δ18O, δ2H) are used in conjunction with groundwater geochemistry and continuous monitoring of groundwater elevation and electrical conductivity. The water table fluctuates by 0.9 to 3.7 m annually, implying recharge rates of 90 and 372 mm yr−1. However, residence times of shallow (11 to 29 m) groundwater determined by 14C are between 100 and 10 000 years, 3H activities are negligible in most of the groundwater, and groundwater electrical conductivity remains constant over the period of study. Deeper groundwater with older 14C ages has lower δ18O values than younger, shallower groundwater, which is consistent with it being derived from greater altitudes. The combined geochemistry data indicate that local recharge from precipitation within the valley occurs through the aquifer window, however much of the groundwater in the Gellibrand Valley predominantly originates from the regional recharge zone, the Barongarook High. The Gellibrand Valley is a regional discharge zone with upward head gradients that limits local recharge to the upper 10 m of the aquifer. Additionally, the groundwater head gradients adjacent to the Gellibrand River are generally upwards, implying that it does not recharge the surrounding groundwater and has limited bank storage. 14C ages and Cl concentrations are well correlated and Cl concentrations may be used to provide a first-order estimate of groundwater residence times. Progressively lower chloride concentrations from 10 000 years BP to the present day are interpreted to indicate an increase in recharge rates on the Barongarook High. © Author(s) 2014

    NBSymple, a double parallel, symplectic N-body code running on Graphic Processing Units

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    We present and discuss the characteristics and performances, both in term of computational speed and precision, of a numerical code which numerically integrates the equation of motions of N 'particles' interacting via Newtonian gravitation and move in an external galactic smooth field. The force evaluation on every particle is done by mean of direct summation of the contribution of all the other system's particle, avoiding truncation error. The time integration is done with second-order and sixth-order symplectic schemes. The code, NBSymple, has been parallelized twice, by mean of the Computer Unified Device Architecture to make the all-pair force evaluation as fast as possible on high-performance Graphic Processing Units NVIDIA TESLA C 1060, while the O(N) computations are distributed on various CPUs by mean of OpenMP Application Program. The code works both in single precision floating point arithmetics or in double precision. The use of single precision allows the use at best of the GPU performances but, of course, limits the precision of simulation in some critical situations. We find a good compromise in using a software reconstruction of double precision for those variables that are most critical for the overall precision of the code. The code is available on the web site astrowww.phys.uniroma1.it/dolcetta/nbsymple.htmlComment: Paper composed by 29 pages, including 9 figures. Submitted to New Astronomy

    Inserting rights and justice into urban resilience : a focus on everyday risk

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    Resilience building has become a growing policy agenda, particularly for urban risk management. While much of the resilience agenda has been shaped by policies and discourses from the global North, its applicability for cities of the global south, particularly African cities, has not been sufficiently assessed. Focusing on rights of urban citizens as the object to be made resilient, rather than physical and ecological infrastructures, may help to address many of the root causes that characterize the unacceptable risks that urban residents face on a daily basis. Linked to this idea, we discuss four entry points for grounding a rights and justice orientation for urban resilience. First, notions of resilience must move away from narrow, financially-orientated risk analyses. Second, opportunities must be created for “negotiated resilience”, to allow for attention to processes that support these goals, as well as for the integration of diverse interests. Third, achieving resilience in ways that do justice to the local realities of diverse urban contexts necessitates taking into account endogenous, locally situated processes, knowledges and norms. And finally, urban resilience needs to be placed within the context of global systems, providing an opportunity for African contributions to help reimagine the role that cities might play in these global finance, politics and science processes

    Insect navigation: do ants live in the now?

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    Visual navigation is a critical behaviour formanyanimals, and it has been particularly well studied in ants. Decades of ant navigation research have uncovered many ways in which efficient navigation can be implemented in small brains. For example, ants show us how visual information can drive navigation via procedural rather than map-like instructions. Two recent behavioural observations highlight interesting adaptive ways in which ants implement visual guidance. Firstly, it has been shownthat the systematic nest searches of ants can be biased by recent experience of familiar scenes. Secondly, ants have been observed to show temporary periods of confusion when asked to repeat a route segment, even if that route segment is very familiar. Taken together, these results indicate that the navigational decisions of ants take into account their recent experiences as well as the currently perceived environment

    Comparison of veterinary drugs and veterinary homeopathy: part 1

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    For many years after its invention around 1796, homeopathy was widely used in people and later in animals. Over the intervening period (1796-2016) pharmacology emerged as a science from Materia Medica (medicinal materials) to become the mainstay of veterinary therapeutics. There remains today a much smaller, but significant, use of homeopathy by veterinary surgeons. Homeopathic products are sometimes administered when conventional drug therapies have not succeeded, but are also used as alternatives to scientifically based therapies and licensed products. The principles underlying the veterinary use of drug-based and homeopathic products are polar opposites; this provides the basis for comparison between them. This two-part review compares and contrasts the two treatment forms in respect of history, constituents, methods of preparation, known or postulated mechanisms underlying responses, the legal basis for use and scientific credibility in the 21st century. Part 1 begins with a consideration of why therapeutic products actually work or appear to do so

    Infant mortality in the hierarchical merging scenario: dependence on gas expulsion time-scales

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    We examine the effects of gas expulsion on initially substructured and out-of-equilibrium star clusters. We perform N-body simulations of the evolution of star clusters in a static background potential before adjusting that potential to model gas expulsion. We investigate the impact of varying the rate at which the gas is removed, and the instant at which gas removal begins. Reducing the rate at which the gas is expelled results in an increase in cluster survival. Quantitatively, this dependence is approximately in agreement with previous studies, despite their use of smooth and virialized initial stellar distributions. However, the instant at which gas expulsion occurs is found to have a strong effect on cluster response to gas removal. We find if gas expulsion occurs prior to one crossing time, cluster response is poorly described by any global parameters. Furthermore, in real clusters the instant of gas expulsion is poorly constrained. Therefore, our results emphasize the highly stochastic and variable response of star clusters to gas expulsion

    Synchronization in complex networks

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    Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.Comment: Final version published in Physics Reports. More information available at http://synchronets.googlepages.com

    Improving Dissemination and Localization of Cultural Heritage Through Multimedia Maps - The Case of Lipari Island

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    Most of the maps in tourist information websites show only the position of the Points of Interest (PoIs)—providing sometime a link to a webpage—making choices difficult. Multimedia maps, instead, could support users in satisfying the traveler needs giving links to information about the PoIs. The developed application supports improved connections between documents and the places they refer to because the user could select PoIs to visit through previews of its multimedia documents. PoIs could also be filtered through their categories and types, accessibility status and time line, thus improving the system usability. This article describes a multimedia map developed as sample for the Lipari Island, the largest of the Aeolian Islands (in Sicily), inscribed in the UNESCO World Heritage List
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