70 research outputs found

    Aeroponic test bed for hypergravity research

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    Taking one pound of food to space costs over $10,000. A plant growth chamber in space would help reduce the cost of transporting food by creating a healthy, long-term source of food that can be used for extended space missions. Currently, there is a lack of knowledge in gravity response mechanisms of plants to facilitate employing such a system. The overarching goal of this project is to add to the current body of knowledge related to growing plants in space by conducting research regarding the effect of hypergravity on cherry belle radish growth. To successfully accomplish this goal, an aeroponic test bed that induces hypergravitational fields ranging from 3gs to 5gs while also providing the nutrients and lighting necessary for growing cherry belle radishes was constructed

    Why have asset price properties changed so little in 200 years

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    We first review empirical evidence that asset prices have had episodes of large fluctuations and been inefficient for at least 200 years. We briefly review recent theoretical results as well as the neurological basis of trend following and finally argue that these asset price properties can be attributed to two fundamental mechanisms that have not changed for many centuries: an innate preference for trend following and the collective tendency to exploit as much as possible detectable price arbitrage, which leads to destabilizing feedback loops.Comment: 16 pages, 4 figure

    The C5a/C5a receptor 1 axis controls tissue neovascularization through CXCL4 release from platelets

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    Platelets contribute to the regulation of tissue neovascularization, although the specific factors underlying this function are unknown. Here, we identified the complement anaphylatoxin C5a-mediated activation of C5a receptor 1 (C5aR1) on platelets as a negative regulatory mechanism of vessel formation. We showed that platelets expressing C5aR1 exert an inhibitory effect on endothelial cell functions such as migration and 2D and 3D tube formation. Growth factor- and hypoxia-driven vascularization was markedly increased in C5ar1(−/−) mice. Platelet-specific deletion of C5aR1 resulted in a proangiogenic phenotype with increased collateralization, capillarization and improved pericyte coverage. Mechanistically, we found that C5a induced preferential release of CXC chemokine ligand 4 (CXCL4, PF4) from platelets as an important antiangiogenic paracrine effector molecule. Interfering with the C5aR1-CXCL4 axis reversed the antiangiogenic effect of platelets both in vitro and in vivo. In conclusion, we identified a mechanism for the control of tissue neovascularization through C5a/C5aR1 axis activation in platelets and subsequent induction of the antiangiogenic factor CXCL4

    Financial Slack and Venture Managers\u27 Decisions to Deek a New Alliance

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    We examine two distinct perspectives to analyze the role of financial slack in the decisions of technology venture managers to seek strategic alliances. According to the capabilities perspective, financial slack provides managers with the ability to maximize the benefits from acquiring missing capabilities through alliance formation, whereas according to the resource dependence perspective, financial slack buffers the managers\u27 motivations to seek alliances as a reaction to external environmental scarcity. Drawing on an experimental design and data on 1632 decisions nested within 51 managers, we find support for a combined perspective demonstrating that managerial discretion in the form of financial slack moderates how internal capabilities and context encourage managers to seek alliances. We discuss implications of our work for the alliance literature

    Microdialysis on Ex Vivo Porcine Ear Skin Can Validly Study Dermal Penetration including the Fraction of Transfollicular Penetration—Demonstrated on Caffeine Nanocrystals

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    Common ex vivo methods for penetration investigations often fail to monitor transfollicular penetration appropriately. In the present investigation, the validity of dermal microdialysis on the ex vivo porcine ear skin to investigate penetration kinetics, including transfollicular penetration, was studied. In setup A, a caffeine nanocrystal formulation was compared to a non-particular caffeine gel formulation. In setup B, two caffeine nanocrystal formulations of different sizes (200 nm, 700 nm) were compared to each other. Microdialysis samples were collected for 46 h. After sampling, the skin layers were separated, homogenized, and caffeine was quantified in all samples. In setup A the area under the curve (AUC) after crystal gel formulation application was 12 times higher than after non-particular formulation application. Setup B showed an increased AUC of 42% in the microdialysis data when the 700 nm caffeine crystals were applied compared to the 200 nm crystals. The microdialysis data was supported by the separation, homogenization and extraction data. Microdialysis performed on ex vivo porcine ear skin is a novel experimental setup. It is of high interest for further investigations since it is able to also capture the impact of follicular and transfollicular penetration kinetics as no other ex vivo setup can
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