1,000 research outputs found
Fluid Flow, Mass, and Heat Transport Laboratory Experiments in Artificially Fractured Rock
The knowledge of flow, mass, and heat transport phenomena in fractured rocks represents an important issue in many situations of science and engineering, such as the groundwater resource management, fractured petroleum reservoirs, nuclear waste disposal, as well as geothermal energy development. Experimental data obtained under controlled conditions such as in laboratory increase the knowledge of the fundamental physics that interest the flow and transport in fracture media and allow us to investigate the behavioral differences between fracture and porous medium. An artificially fractured rock sample of parallelepiped shape (0.60 × 0.80 × 0.08 m3) has been created, and the flow, mass, and heat transport behavior have been observed. The carried out experiments show the existence of non-Darcian flow regime that cannot be neglected. The latter influences the mass transport behavior giving rise to a delay in mass migration, enhancing the nonequilibrium behavior, whereas the dispersion phenomena seem not be influenced. Heat transport shows a very different behavior compared to mass transport. Convective thermal velocity is lower than mass velocity, whereas thermal dispersion is higher than solute dispersion
Graft Detachment After Descemet's Stripping Automated Endothelial Keratoplasty in Bullous Keratopathy and Fuchs Dystrophy
Descemet’s stripping automated endothelial keratoplasty (DSAEK) is a surgical technique for corneal transplantation in case of corneal decompensation. One of the main complications is graft detachment (GD) recoverable with Air Re-bubbling (ARB). The aim of this retrospective, interventional case series was to identify factors related to this complication in eyes operated for bullous keratopathy (BK) and Fuchs dystrophy (FD). We considered one-hundred patients who underwent DSAEK for BK or FD between January 2016 and October 2017 at Department of Ophthalmology, Policlinico Universitario of Bari, Italy. Studied parameters included physiological and pathological anamnesis of both donors and recipients and properties of donor’s lenticules and of the recipient’s corneas. Data was analyzed using One-way ANOVA with Tukey post hoc test and Chi-square test with Odds Ratio (OR) calculation. We grouped patients according to diagnosis. GD occurred in 9 eyes affected by BK and 19 by FD (p=0.003, OR = 0.25, 95% CI, 0.098-0.62). It was recovered with ARB. In BK, ARB correlated to complicated cataract extraction (p=0.04, OR = 7.83, 95% CI, 1.28 – 47.98) and aphakia (p=0.026, OR = 54.38, 95% CI, 2.51 - 11.76). In FD, ARB was associated to donor’s death for neoplasia (p=0.06, OR= 4.04, 95% CI, 1.06 – 15.37). No other differences were found. In conclusion, we could hypothesize that in FD patients, donor’s cancer therapy may play a role on altered corneal fibroblast metabolism, activating a synergetic effect between chemotherapy and genetic alteration of FD, which may lead to an altered adhesion of donor’s lenticule on recipient's stroma. In BK patients, complicated cataract extraction and aphakic status of recipients’ eye may contribute to altered adhesion of donor’s lenticule post-DSAEK
Non-linear fractal percolation experiments in carstic and aggregation soils
The present study compares the performances and reliabilities of the classical Mobile – Immobile Model (MIM)
and the Explicit Network Model (ENM) that takes expressly into account the network geometry for describing
tracer transport behaviour in a fractured sample at bench scale. Though ENM shows better fitting results than
MIM, the latter remains still valid as it proves to describe the observed curves quite well.
The results show that the presence of nonlinear flow plays an important role in the behaviour of solute
transport. Firstly the distribution of solute according to different pathways is not constant but it is related to the
flow rate. Secondly nonlinear flow influences advection, in that it leads to a delay in solute transport respect to the
linear flow assumption. Whereas nonlinear flow does not show to be related with dispersion. The experimental
results show that in the study case the geometrical dispersion dominates the Taylor dispersion. However the
interpretation with the ENM model shows a weak transitional regime from geometrical dispersion to Taylor
dispersion for high flow rates.Postprint (published version
Graft Detachment After Descemet's Stripping Automated Endothelial Keratoplasty in Bullous Keratopathy and Fuchs Dystrophy
Descemet’s stripping automated endothelial keratoplasty (DSAEK) is a surgical technique for corneal transplantation in case of corneal decompensation. One of the main complications is graft detachment (GD) recoverable with Air Re-bubbling (ARB). The aim of this retrospective, interventional case series was to identify factors related to this complication in eyes operated for bullous keratopathy (BK) and Fuchs dystrophy (FD). We considered one-hundred patients who underwent DSAEK for BK or FD between January 2016 and October 2017 at Department of Ophthalmology, Policlinico Universitario of Bari, Italy. Studied parameters included physiological and pathological anamnesis of both donors and recipients and properties of donor’s lenticules and of the recipient’s corneas. Data was analyzed using One-way ANOVA with Tukey post hoc test and Chi-square test with Odds Ratio (OR) calculation. We grouped patients according to diagnosis. GD occurred in 9 eyes affected by BK and 19 by FD (p=0.003, OR = 0.25, 95% CI, 0.098-0.62). It was recovered with ARB. In BK, ARB correlated to complicated cataract extraction (p=0.04, OR = 7.83, 95% CI, 1.28 – 47.98) and aphakia (p=0.026, OR = 54.38, 95% CI, 2.51 - 11.76). In FD, ARB was associated to donor’s death for neoplasia (p=0.06, OR= 4.04, 95% CI, 1.06 – 15.37). No other differences were found. In conclusion, we could hypothesize that in FD patients, donor’s cancer therapy may play a role on altered corneal fibroblast metabolism, activating a synergetic effect between chemotherapy and genetic alteration of FD, which may lead to an altered adhesion of donor’s lenticule on recipient's stroma. In BK patients, complicated cataract extraction and aphakic status of recipients’ eye may contribute to altered adhesion of donor’s lenticule post-DSAEK
Non-phenomenological description of the time-resolved emission in solution with quantum-classical vibronic approaches-application to coumarin C153 in methanol
We report a joint experimental and theoretical work on the steady-state spectroscopy and time-resolved emission of the coumarin C153 dye in methanol. The lowest energy excited state of this molecule is characterized by an intramolecular charge transfer thus leading to remarkable shifts of the time-resolved emission spectra, dictated by the methanol reorganization dynamics. We selected this system as a prototypical test case for the first application of a novel computational protocol aimed at the prediction of transient emission spectral shapes, including both vibronic and solvent effects, without applying any phenomenological broadening. It combines a recently developed quantum–classical approach, the adiabatic molecular dynamics generalized vertical Hessian method (Ad-MD (Formula presented.) VH), with nonequilibrium molecular dynamics simulations. For the steady-state spectra we show that the Ad-MD|gVH approach is able to reproduce quite accurately the spectral shapes and the Stokes shift, while a ∼0.15 eV error is found on the prediction of the solvent shift going from gas phase to methanol. The spectral shape of the time-resolved emission signals is, overall, well reproduced, although the simulated spectra are slightly too broad and asymmetric at low energies with respect to experiments. As far as the spectral shift is concerned, the calculated spectra from 4 ps to 100 ps are in excellent agreement with experiments, correctly predicting the end of the solvent reorganization after about 20 ps. On the other hand, before 4 ps solvent dynamics is predicted to be too fast in the simulations and, in the sub-ps timescale, the uncertainty due to the experimental time resolution (300 fs) makes the comparison less straightforward. Finally, analysis of the reorganization of the first solvation shell surrounding the excited solute, based on atomic radial distribution functions and orientational correlations, indicates a fast solvent response (≈100 fs) characterized by the strengthening of the carbonyl–methanol hydrogen bond interactions, followed by the solvent reorientation, occurring on the ps timescale, to maximize local dipolar interactionsThis research was funded by ICSC—Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, funded by European Union—NextGenerationEU— PNRR, Missione 4 Componente 2 Investimento 1.4 (F.S and G.P); MICINN Project PID2019-110091GBI00 (JC); H2020-LC-SC3-2020-RES-RIA-101006839 project “CONDOR” and MUR-PNRR (NEST— Network 4 Energy Sustainable Transition, Estended Partnership—PE000002 (SG, BV and NA
Study and development of a fluorescence based sensor system for monitoring oxygen in wine production: The WOW project
The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of the winemaking process, both for monitoring and for control. The WOW project (Deployment of WSAN technology for monitoring Oxygen in Wine products) has focused on the design and the development of an innovative device for monitoring the oxygen levels in wine. This system is based on the use of an optical fiber to measure the luminescent lifetime variation of a reference metal/porphyrin complex, which decays in presence of oxygen. The developed technology results in a high sensitivity and low cost sensor head that can be employed for measuring the dissolved oxygen levels at several points inside a wine fermentation or aging tank. This system can be complemented with dynamic modeling techniques to provide predictive behavior of the nutrient evolution in space and time given few sampled measuring points, for both process monitoring and control purposes. The experimental validation of the technology has been first performed in a controlled laboratory setup to attain calibration and study sensitivity with respect to different photo-luminescent compounds and alcoholic or non-alcoholic solutions, and then in an actual case study during a measurement campaign at a renown Italian winery
Outcome of Allogeneic Peripheral Blood Stem Cell Transplantation by Donor Graft CD3+/Tregs Ratio: A Single-Center Experience
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