16,677 research outputs found

    Sphingosine 1-phosphate in renal diseases

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    Because of its highly bioactive properties sphingosine 1-phosphate (S1P) is an attractive target for the treatment of several diseases. Since the expression of sphingosine kinases as well as S1P receptors was demonstrated in the kidney, questions about the physiological and pathophysiological functions of S1P in this organ have been raised. In this review, we summarize the current state of knowledge about S1P-mediated functions in the kidney. A special focus is put on S1P modulated signal transduction in renal glomerular and tubular cells and consequences for the development and treatment of several kidney diseases, diabetic nephropathy, glomerulonephritis, ischemia-reperfusion injury, as well as for Wilms tumor progression

    Quantum state majorization at the output of bosonic Gaussian channels

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    Quantum communication theory explores the implications of quantum mechanics to the tasks of information transmission. Many physical channels can be formally described as quantum Gaussian operations acting on bosonic quantum states. Depending on the input state and on the quality of the channel, the output suffers certain amount of noise. For a long time it has been conjectured, but never proved, that output states of Gaussian channels corresponding to coherent input signals are the less noisy ones (in the sense of a majorization criterion). In this work we prove this conjecture. Specifically we show that every output state of a phase insensitive Gaussian channel is majorized by the output state corresponding to a coherent input. The proof is based on the optimality of coherent states for the minimization of strictly concave output functionals. Moreover we show that coherent states are the unique optimizers.Comment: 7 pages, 1 figure. Published versio

    Interaction of CO with an Au monatomic chain at different strains: electronic structure and ballistic transport

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    We study the energetics, the electronic structure, and the ballistic transport of an infinite Au monatomic chain with an adsorbed CO molecule. We find that the bridge adsorption site is energetically favored with respect to the atop site, both at the equilibrium Au-Au spacing of the chain and at larger spacings. Instead, a substitutional configuration requires a very elongated Au-Au bond, well above the rupture distance of the pristine Au chain. The electronic structure properties can be described by the Blyholder model, which involves the formation of bonding/antibonding pairs of 5{\sigma} and 2{\pi}* states through the hybridization between molecular levels of CO and metallic states of the chain. In the atop geometry, we find an almost vanishing conductance due to the 5{\sigma} antibonding states giving rise to a Fano-like destructive interference close to the Fermi energy. In the bridge geometry, instead, the same states are shifted to higher energies and the conductance reduction with respect to pristine Au chain is much smaller. We also examine the effects of strain on the ballistic transport, finding opposite behaviors for the atop and bridge conductances. Only the bridge geometry shows a strain dependence compatible with the experimental conductance traces

    Expanding a fluorescent RNA alphabet: synthesis, photophysics and utility of isothiazole-derived purine nucleoside surrogates.

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    A series of emissive ribonucleoside purine mimics, all comprised of an isothiazolo[4,3-d]pyrimidine core, was prepared using a divergent pathway involving a key Thorpe-Ziegler cyclization. In addition to an adenosine and a guanosine mimic, analogues of the noncanonical xanthosine, isoguanosine, and 2-aminoadenosine were also synthesized and found to be emissive. Isothiazolo 2-aminoadenosine, an adenosine surrogate, was found to be particularly emissive and effectively deaminated by adenosine deaminase. Competitive studies with adenosine deaminase with each analogue in combination with native adenosine showed preference for the native substrate while still deaminating the isothiazolo analogues

    Data collection framework for understanding UFT within city logistics solutions

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    Urban Freight Transport (UFT) is a fundamental component of city life. It involves a vast range of activities resulting from relationships among different actors with conflicting needs and goals. Manufacturers are interested in fast and on-time deliveries, retailers require complete assortment and frequent deliveries, citizens wish to have easy access to goods while not losing their quality of life and City Authorities have to face negative externalities related to UFT (i.e. congestion, air and noise pollution, and safety). Concretely, few cities have a well-developed and comprehensive city logistics strategy because authorities generally focus their attention on passenger transport. When city logistics measures have been conceived and implemented, frequently private requirements have not been considered sufficiently. The European Commission includes the lack of data and understanding of freight flows among the main obstacles to the improvement of operational efficiency and planning process for a sustainable UFT in economic, social and environmental terms. Also, the research community raises the issue of the unavailability or the low quality of data on urban freight and the need to identify effective data collection methods in order to understand processes and actors' behavior and then define appropriate city logistics solutions. The NOVELOG EU project is providing city authorities and practitioners with a new framework aimed at systematizing all data to be collected, directly or indirectly, and to be elaborated in order to understand and represent the different aspects of the UFT sector. In order to achieve a complete knowledge, the framework approaches this sector according to four main thematic pillars: 1) profile of major supply chains served in the urban area under study; 2) mapping of urban freight and service trips activity; 3) organizational and legal framework; 4) procedural and technological methods and innovations. The present paper introduces the framework and the guidance it provides to its target audience

    Analysis of the Impact and Value of Community Benefit Clauses in Procurement

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    This research draws on data from a large scale e-survey of public organisations and in-depth analysis of 24 individual contracts
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