314 research outputs found

    Quivers and moduli spaces of pointed curves of genus zero

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    We construct moduli spaces of representations of quivers over arbitrary schemes and show how moduli spaces of pointed curves of genus zero like the Grothendieck-Knudsen moduli spaces M0,n\overline{M}_{0,n} and the Losev-Manin moduli spaces Ln\overline{L}_n can be interpreted as inverse limits of moduli spaces of representations of certain bipartite quivers. We also investigate the case of more general Hassett moduli spaces M0,a\overline{M}_{0,a} of weighted pointed stable curves of genus zero.Comment: 41 page

    The functor of toric varieties associated with Weyl chambers and Losev-Manin moduli spaces

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    A root system RR of rank nn defines an nn-dimensional smooth projective toric variety X(R)X(R) associated with its fan of Weyl chambers. We give a simple description of the functor of X(R)X(R) in terms of the root system RR and apply this result in the case of root systems of type AA to give a new proof of the fact that the toric variety X(An)X(A_n) is the fine moduli space Lˉn+1\bar{L}_{n+1} of stable (n+1)(n+1)-pointed chains of projective lines investigated by Losev and Manin.Comment: 25 page

    Toric orbifolds associated to Cartan matrices

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    We investigate moduli stacks of pointed chains of projective lines related to the Losev-Manin moduli spaces and show that these moduli stacks coincide with certain toric stacks which can be described in terms of the Cartan matrices of root systems of type A. We also consider variants of these stacks related to root systems of type B and C.Comment: 34 page

    Aptamer-modified polymer nanoparticles for targeted drug delivery

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    The purpose of this study was to develop a model system for targeted drug delivery. This system should enable targeted drug release at a certain tissue in the body. In conventional drug delivery systems, drugs are often delivered unspecifically resulting in unwarranted adverse effects. To circumvent this problem, there is an increasing demand for the development of intelligent drug delivery systems allowing a tissue-specific mode of delivery. Within this study, nanoparticles consisting of two biocompatible polymers are used. Because of their small size, nanoparticles are well-suited for effective drug delivery. The small size affects their movement through cell and tissue barriers. Their cellular uptake is easier when compared to larger drug delivery systems. Paclitaxel was encapsulated into the nanoparticles as a model drug, and to achieve specific targeting an aptamer directed against lung cancer cells was coupled to the nanoparticles surface. Nanoparticles were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), and nanotracking analysis (NTA). Also their surface charge was characterized from ζ-potential measurements. Their preparation was optimized and subsequently specificity of drug-loaded and aptamer-functionalized nanoparticles was investigated using lung cancer cells. © 2016 by De Gruyter

    Patient experiences with oily skin: The qualitative development of content for two new patient reported outcome questionnaires

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    <p>Abstract</p> <p>Objective</p> <p>To develop the content for two new patient reported outcome (PRO) measures to: a) assess the severity of symptoms; and b) the impact of facial skin oiliness on emotional wellbeing using qualitative data from face to face, and internet focus groups in Germany and the US.</p> <p>Methods</p> <p>Using input from initial treatment satisfaction focus groups (n = 42), a review of relevant literature and expert clinicians (n = 3), a discussion guide was developed to guide qualitative inquiry using Internet focus groups (IFGs). IFGs were conducted with German (n = 26) and US (n = 28) sufferers of oily skin. Questionnaire items were generated using coded transcript data from the focus groups. Cognitive debriefing was conducted online with 42 participants and face to face with an additional five participants to assess the comprehension of the items.</p> <p>Results</p> <p>There were equal numbers of male and female participants; mean age was 35.4 (SD 9.3) years. On average, participants had had oily skin for 15.2 years, and 74% (n = 40) reported having mild-moderate acne. Participants reported using visual, tactile and sensory (feel without touching their face) methods to evaluate the severity of facial oiliness. Oily facial skin had both an emotional and social impact, and was associated with feelings of unattractiveness, self-consciousness, embarrassment, irritation and frustration. Items were generated for a measure of oily skin severity (Oily Skin Self-Assessment Scale) and a measure of the impact of oily skin on emotional well-being (Oily Skin Impact Scale). Cognitive debriefing resulted in minor changes to the draft items and confirmed their face and content validity.</p> <p>Conclusion</p> <p>The research provides insight into the experience of having oily skin and illustrates significant difficulties associated with the condition. Item content was developed for early versions of two PRO measures of the symptoms and emotional impact of oily facial skin. The psychometric validation of these measures reported elsewhere.</p
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