44,686 research outputs found

    Diffractive Phenomena at Tevatron

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    Preliminary results from the D0 experiment on jet production with rapidity gaps in ppˉp\bar{p} collisions are presented. A class of dijet events with a forward rapidity gap is observed at center-of-mass energies s\sqrt{s} = 1800 GeV and 630 GeV. The number of events with rapidity gaps at both center-of-mass energies is significantly greater than the expectation from multiplicity fluctuations and is consistent with a hard single diffractive process. A class of events with two forward gaps and central dijets are also observed at 1800 GeV. This topology is consistent with hard double pomeron exchange. We also present proposed plans for extending these analysis into Run II through the use of a forward proton detector.Comment: plain tex, 5 pages, 2 figure

    Results on Charmonium-like States at BaBar

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    We present recent results on charmonium and charmonium-like states from the BaBar B-factory located at the PEP-II asymmetric energy e+ee^{+}e^{-} storage ring at the SLAC National Accelerator Laboratory.Comment: 7 pages, 5 Figures, Proceeding of the Conference "QCD@Work - International Workshop on QCD - Theory and Experiment" 18-21 June 2012, Lecce Ital

    Weinhold'length in an isochoric thermodynamic system at constant heat capacity

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    The purpose of this paper is to study thermodynamic length of an isochoric two dimensional thermodynamic system with constant heat capacity. We find that length is related to the heat flow into the substance. We give examples of Ideal gas and Van der Waals gas

    Vibronic effects on electronic spectra and nonadiabatic photophysics. A quantum/classical dynamical approach.

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    Quantum vibronic effects have a remarkable impact on the lineshape of electronic spectra.1 They can also play an important role in the dynamics of photophysical processes like internal conversions at Conical Intersections or charge and energy transfer in multichromophoric systems. Recent advancements allow a fair description of such effects in rigid (harmonic) molecules in gas phase.1-4 However, in biology and in material science the photoexcited chomophores are usually embedded in a solvent, possibly establishing with them specific interactions, or even in more complex and heterogeneous environments. Moreover, many systems with interesting optical properties are flexible, i.e. the optical transition triggers large-amplitude curvilinear distortions, and this challenges the applicability of harmonic approximation. Trajectory based approaches are very suitable to deal with these scenarios but they neglect quantum nuclear effects. We are currently working with the hope to devise robust hybrid quantum/classical (QC) approaches to merge the potentialities of trajectory based methods and those of the quantum vibronic methods developed for rigid systems in gas phase or implicit solvents.1,5-6 The system is partitioned in two subsystems: a quantum core (the chromophore or just its high-frequency modes) and an environment (which can include also large amplitude motions of the system itself and is treated at a more approximate classical level) and the challenge is the reliable description of their mutual couplings. We will illustrate our recent results with a number of examples ranging from the chiro-otpical properties of flexible conjugated systems (e.g. oligothiophenes) to the nonadiabatic decay of photoexcited DNA nucleobases7 in acqueous solution. 8-12 1. F. Santoro, D. Jacquemin, WIREs Comput Mol Sci 6, 460–486, 2016 2. M. H Beck,. A Jäckle,. G. A Worth, H.-D Meyer,. Physics Report 2000, 324 3. L. S. Cederbaum, E. Gindensperger, and I. Burghardt, Phys. Rev. Lett. 94, 113003, 2005. 4. D. Picconi, F. Avila, R. Improta, A. Lami, F. Santoro, Faraday Discuss, 163, 223, 2013 5. F. Avila, R. Improta, F. Santoro, V. Barone, Phys Chem Chem Phys. 17007, 13, 2011 6. F. Avila, J. Cerezo, J. Soto, R. Improta, F. Santoro, Comp. Chem. Theor. 1040-1041, 328, 2014 7. R. Improta, E. Stendardo, F. Avila, F. Santoro, Chem. Phys. Chem. 15 3320, 2014 8. R. Improta, F. Santoro, L. Blancafort, Chem . Rev 116, 3540 2016 9. D. Padula, F. Santoro, G. Pescitelli RSC Adv. 6, 37928, 116, 3540, 2016 10. J. Cerezo, F. Avila, G. Prampolini, F. Santoro, J. Chem. Theor. Comp. 11, 5810, 2015 11. J. Cerezo, G. Mazzeo, G. Longhi, S. Abbate, F. Santoro J. Phys. Chem. Lett. 7, 4891, 2016 12. Y. Liu, J. Cerezo, N. Lin, X. Zhao, R. Improta, F. Santoro submitted to J. Phys. Chem. Lett.Universidad de Málaga. Cammous de Excelencia Internacional Andalucía Tech

    Introducing monitoring and automation in cartilage tissue engineering, toward controlled clinical translation

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    The clinical application of tissue engineered products requires to be tightly connected with the possibility to control the process, assess graft quality and define suitable release criteria for implantation. The aim of this work is to establish techniques to standardize and control the in vitro engineering of cartilage grafts. The work is organized in three sub-projects: first a method to predict cell proliferation capacity was studied, then an in line technique to monitor the draft during in vitro culture was developed and, finally, a culture system for the reproducible production of engineered cartilage was designed and validated. Real-time measurements of human chondrocyte heat production during in vitro proliferation. Isothermal microcalorimetry (IMC) is an on-line, non-destructive and high resolution technique. In this project we aimed to verify the possibility to apply IMC to monitor the metabolic activity of primary human articular chondrocytes (HAC) during their in vitro proliferation. Indeed, currently, many clinically available cell therapy products for the repair of cartilage lesions involve a process of in vitro cell expansion. Establishing a model system able to predict the efficiency of this lengthy, labor-intensive, and challenging to standardize step could have a great potential impact on the manufacturing process. In this study an optimized experimental set up was first established, to reproducible acquire heat flow data; then it was demonstrated that the HAC proliferation within the IMC-based model was similar to proliferation under standard culture conditions, verifying its relevance for simulating the typical cell culture application. Finally, based on the results from 12 independent donors, the possible predictive potential of this technique was assessed. Online monitoring of oxygen as a non-destructive method to quantify cells in engineered 3D tissue constructs. This project aimed at assessing a technique to monitor graft quality during production and/or at release. A quantitative method to monitor the cells number in a 3D construct, based on the on-line measurement of the oxygen consumption in a perfusion based bioreactor system was developed. Oxygen levels dissolved in the medium were monitored on line, by two chemo-optic flow-through micro-oxygen sensors connected at the inlet and the outlet of the bioreactor scaffold chamber. A destructive DNA assay served to quantify the number of cells at the end of the culture. Thus the oxygen consumption per cell could be calculated as the oxygen drop across the perfused constructs at the end of the culture period and the number of cells quantified by DNA. The method developed would allow to non-invasively monitoring in real time the number of chondrocytes on the scaffold. Bioreactor based engineering of large-scale human cartilage grafts for joint resurfacing. The aim of this project was to upscale the size of engineered human cartilage grafts. The main aim of this project consisted in the design and prototyping of a direct perfusion bioreactor system, based on fluidodynamic models (realized in collaboration with the Institute for Bioengineering of Catalonia, Spain), able to guarantee homogeneous seeding and culture conditions trough the entire scaffold surface. The system was then validated and the capability to reproducibly support the process of tissue development was tested by histological, biochemical and biomechanical assays. Within the same project the automation of the designed scaled up bioreactor system, thought as a stand alone system, was proposed. A prototype was realized in collaboration with Applikon Biotechnology BV, The Netherlands. The developed system allows to achieve within a closed environment both cell seeding and culture, controlling some important environmental parameters (e.g. temperature, CO2 and O2 tension), coordinating the medium flow and tracking culture development. The system represents a relevant step toward process automation in tissue engineering and, as previously discussed, enhancing the automation level is an important requirement in order to move towards standardized protocols of graft generation for the clinical practice. These techniques will be critical towards a controlled and standardized procedure for clinical implementation of tissue engineering products and will provide the basis for controlled in vitro studies on cartilage development. Indeed the resulting methods have already been integrated in a streamlined, controlled, bioreactor based protocol for the in vitro production of up scaled engineered cartilage drafts. Moreover the techniques described will serve as the foundation for a recently approved Collaborative Project funded by the European Union, having the goal to produce cartilage tissue grafts. In order to reach this goal the research based technologies and processes described in this dissertation will be adapted for GMP compliance and conformance to regulatory guidelines for the production of engineered tissues for clinical use, which will be tested in a clinical trial
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