26 research outputs found
Methylprednisolone-induced toxic hepatitis after intravenous pulsed therapy for multiple sclerosis relapses
High-dose, intravenous methylprednisolone (MP) is the only recommended first-line treatment for multiple sclerosis relapses. However, there are increasing reports on liver toxicity induced by this treatment regimen. We report of 4 multiple sclerosis patients with no history of viral/metabolic liver disorders or alcohol/hepatotoxic drug intake, who developed hypertransaminasaemia following intravenous MP. In 2 of the patients, liver biopsy showed periportal fibrosis, piecemeal necrosis, and inflammatory cell infiltrates. A rechallenge test confirmed a causal association in 1 case. MP-induced liver toxicity may be more frequent than commonly thought and it is important to report this adverse reaction, which is potentially lethal, and to raise awareness on the potential hepatotoxicity of corticosteroid pulses
Endoscopic management of patients with post-surgical leaks involving the gastrointestinal tract: a large case series
Background: Post-surgical anastomotic leaks often require a re-intervention, are associated with a definite morbidity and mortality, and with relevant costs. We described a large series of patients with different post-surgical leaks involving the gastrointestinal tract managed with endoscopy as initial approach. Methods: This was a retrospective analysis of prospectively collected cases with anastomotic leaks managed with different endoscopic approaches (with surgical or radiological drainage when needed) in two endoscopic centres during 5 years. Interventions included: (1) over-the-scope clip (OTSC) positioning; (2) placement of a covered self-expanding metal stent (SEMS); (3) fibrin glue injection (Tissucol); and (4) endo-sponge application, according to both the endoscopic feature and patient’s status. Results: A total of 76 patients underwent endoscopic treatment for a leak either in the upper (47 cases) or lower (29 cases) gastrointestinal tract, and the approach was successful in 39 (83%) and 22 (75.9%) patients, respectively, accounting for an overall 80.3% success rate. Leak closure was achieved in 84.9% and 78.3% of patients managed by using a single or a combination of endoscopic devices. Overall, leak closure failed in 15 (19.7%) patients, and the surgical approach was successful in all 14 patients who underwent re-intervention, whilst one patient died due to sepsis at 7 days. Conclusions: Our data suggest that an endoscopic approach, with surgical or radiological drainage when needed, is successful and safe in the majority of patients with anastomotic gastrointestinal leaks. Therefore, an endoscopic treatment could be attempted before resorting to more invasive, costly and risky re-intervention
Endoscopic management of patients with post-surgical leaks involving the gastrointestinal tract: a large case series
Background: Post-surgical anastomotic leaks often require a re-intervention, are associated with a definite morbidity and mortality, and with relevant costs. We described a large series of patients with different post-surgical leaks involving the gastrointestinal tract managed with endoscopy as initial approach. Methods: This was a retrospective analysis of prospectively collected cases with anastomotic leaks managed with different endoscopic approaches (with surgical or radiological drainage when needed) in two endoscopic centres during 5 years. Interventions included: (1) over-the-scope clip (OTSC) positioning; (2) placement of a covered self-expanding metal stent (SEMS); (3) fibrin glue injection (Tissucol); and (4) endo-sponge application, according to both the endoscopic feature and patient’s status. Results: A total of 76 patients underwent endoscopic treatment for a leak either in the upper (47 cases) or lower (29 cases) gastrointestinal tract, and the approach was successful in 39 (83%) and 22 (75.9%) patients, respectively, accounting for an overall 80.3% success rate. Leak closure was achieved in 84.9% and 78.3% of patients managed by using a single or a combination of endoscopic devices. Overall, leak closure failed in 15 (19.7%) patients, and the surgical approach was successful in all 14 patients who underwent re-intervention, whilst one patient died due to sepsis at 7 days. Conclusions: Our data suggest that an endoscopic approach, with surgical or radiological drainage when needed, is successful and safe in the majority of patients with anastomotic gastrointestinal leaks. Therefore, an endoscopic treatment could be attempted before resorting to more invasive, costly and risky re-intervention
A new push–pull dye for semi-transparent p-type dye-sensitized solar cells: tuning conjugation by sexithiophene chain engineering
We report on the synthesis of two new dyes to be employed as sensitizers in p-type dye-sensitized solar cells (DSCs). The design of the two new molecules under consideration has been inspired by the state-of-art dye PMI-6 T-TPA. In particular, a specific engineering of the thiophene-based central core is here considered to favour structural planarity between an oligothiophenic π-spacer (a sexithiophene), and the acceptor and donor units made by peryleneimide (PMI) and triphenylamine (TPA) moieties, respectively. This leads to a wide absorption in the NIR with stabilization of the HOMO energy level in the resulting dyes, as supported by TD-DFT simulations and spectroscopic characterization. When tested as sensitizers in NiOx-based p-type DSCs, A6D (with an Acceptor-π-Donor structure) outperforms both its counterpart with a Donor-π-Donor structure (D6D) and P1, a benchmark dye in the field of p-DSCs. With A6D dye-sensitizer the resulting DSC device presents the quite remarkable value of stabilized efficiency as high as 0.15 % when I-/I3- is employed as redox couple and nanostructured NiOx photocathode is thick less than 2 μm and does not contain any blocking layer. Notwithstanding the panchromatic feature of the sensitizer, A6D-based devices show an average visible transmittance (AVT) of 8 %. Such a result paves the way toward the application of these types of multifunctional dyes in semi-transparent solar cells
0D Modeling of Fuel Tank for Vapor Generation
Petrol vapor emissions are the main source of pollution for both standard and hybrid vehicles. They are mainly generated by gasoline evaporation from the fuel tank of both running and parked vehicles; it is mostly driven by fuel temperature variation due to daily temperature changes (if parked) and heat from engine (if running). To prevent its dispersion in the environment, the vapor generated in the fuel tank is usually stored in a carbon canister filter that must be periodically “purged” in order to prevent its saturation, by venting it to the intake manifold. Canister management, made by the Engine Control Unit (ECU), becomes even more critical for hybrid-electric vehicles because thermal engine is often off, thus purging cannot take place. A pressurized fuel tank is often used for hybrid applications, to further isolate vapor from environment, making the fuel system even more complex to model. System design optimization is usually based on experience and experimental correlations, which require time and cost. Thus, comes the need for a comprehensive predictive model useful for both vehicle components (fuel tank and carbon canister) and ECU software design.
A 0D Matlab® model is proposed, which can predict vapor generation from an arbitrary tank in standard and arbitrary thermal cycles, with arbitrary tank capacity, geometry and construction and at different filling levels. It is based on a system of thermo-fluid-dynamic differential equations and semi-empirical correlations that is iteratively solved in time. Model calibration has been performed by using a small size test tank and validation has been completed on full size tanks for both standard and hybrid-electric applications. The main driving force for vapor generation has been shown to be the amount of empty volume on top of the tank; other significant effects come from tank volume, material, external surface as well as fuel properties. Ongoing work is to develop and integrate a carbon canister loading/purging model, with the aim to build a full model of the vapor system
Evaporative Emissions from Automotive Gasoline Fuel Tank Refueling: Experimental Activity and Numerical Simulation
Vehicle evaporative emission is one of the most important sources of pollution from a gasoline-fueled vehicle. Since international regulations on Volatile Organic Compounds (VOC) emission are becoming increasingly stringent every year, the study of the VOC generation has become of fundamental importance. It is known that VOC generation is particularly high during the refueling phase: fresh fuel coming from the refueling nozzle impacts on the filling pipe wall and it is a source for sloshing in the fuel tank. Fuel vapor generated can be collected by a vapor recovery nozzle and stored in the gas station tank (Stage II vapor recovery system, European normative) or trapped by the vehicle carbon canister (On-board Refueling Vapor Recovery system, U.S. normative). In this activity, an automotive gasoline fuel tank for U.S. applications has been used for both experimental and numerical analyses, provided by FCA. Experiments were performed in FCA laboratories, in a sealed and thermal controlled environment (mini-SHED): vapor flow exiting the fuel tank during refueling has been measured, and fuel vapor mass has been evaluated by dynamically measuring the weight variation of a carbon canister filter connected to the fuel tank vent system. A CFD model was built based on CAD geometries provided by FCA, and numerical analysis of the refueling process has then been executed by using a commercial 3D CFD software. Results were then compared with experimental data. This activity is a part of a collaboration between University of Naples Federico II and FCA Italy about fuel vapor emissions control and prediction
Experimental adsorption and desorption characterization of a gasoline-fueled vehicle carbon canister for European application filled with n-butane and nitrogen mixtures
The evaporative emission control system (EVAP system) is the most commonly used strategy to limit the unburned petrol vapor emissions from a gasoline-fueled vehicle fuel tank, in order to comply with the international regulations on Volatile Organic Compounds (VOCs) emission. A carbon canister is used to collect and store the gasoline vapors generated in the tank, then it is purged by the engine intake manifold depression and the vapors are burned in the engine along with the fresh charge. In this activity, a 1.0 L carbon canister for European gasoline vehicles, provided by FCA, has been used for an experimental analysis, in order to characterize its adsorption and desorption behavior. A standard mixture of n-butane and nitrogen (40 g/h of n-butane, 50% vol. with nitrogen) has been used for loading the canister to breakthrough (2 g); canister purging has been performed with 3000 bed volumes of nitrogen flux at 25 L/min. Tests have been performed in FCA laboratories, at the Pomigliano Technical Center. Canister mass gain has been measured during the tests and after each test with a precision weight scale. Internal temperatures have also been measured by K-type thermocouples placed inside the carbon bed; due to the adsorption process, bed temperatures can reach 70 °C. After several tests, results on mass gain show an “aging” trend of the activated carbons
Analyses of the Post-reflux Swallow-induced Peristaltic Wave Index and Nocturnal Baseline Impedance Parameters Increase the Diagnostic Yield of Impedance-pH Monitoring of Patients With Reflux Disease
BACKGROUND & AIMS:
Analyses of impedance parameters such as the post-reflux swallow-induced peristaltic wave (PSPW) index and the mean nocturnal baseline impedance (MNBI) have been proposed to increase the accuracy of diagnosis of reflux disease. We assessed whether these improve the diagnostic yield of impedance pH monitoring of reflux disease.
METHODS:
We performed a prospective study of consecutive patients with proton pump inhibitor-responsive heartburn who underwent 24-hour impedance pH monitoring at hospitals in Italy from January 2011 through December 2013. Reviewers blindly analyzed off-therapy impedance pH tracings from 289 patients with proton pump inhibitor-responsive heartburn, 68 with erosive reflux disease and 221 with non-erosive reflux disease (NERD), along with 50 healthy individuals (controls). The PSPW index, the MNBI, the esophageal acid exposure time, the number of total refluxes, and the bolus exposure were calculated, as well as the symptom association probability (SAP) and the symptom index (SI).
RESULTS:
In receiver operating characteristic analysis, the area under curve of the PSPW index (0.977; 95% confidence interval, 0.961-0.993) was significantly greater than that of the other impedance pH parameters in identifying patients with reflux disease (P < .001). The PSPW index and the MNBI identified patients with erosive reflux disease with the highest level of sensitivity (100% and 91%, respectively), as well as the 118 pH-positive (99% and 86%) and 103 pH-negative (77% and 56%) cases of NERD. The PSPW index and the MNBI identified pH-negative NERD with the highest level of sensitivity; values were 82% and 52% for the 65 SAP-positive and/or SI-positive cases and 68% and 63% for the 38 SAP-negative and SI-negative cases. Diagnoses of NERD were confirmed by pH-only criteria, including those that were positive on the basis of the SAP or SI, for 165 of 221 cases (75%) and by impedance pH criteria for 216 of 221 cases (98%) (P = .001).
CONCLUSIONS:
The PSPW index and the MNBI increase the diagnostic yield of impedance pH monitoring of patients with reflux disease. Analysis of impedance pH data by calculating the PSPW index and the MNBI can increase the accuracy of diagnosis of patients with reflux disease, compared with pH-only data