1,166 research outputs found
The ship model basin of Naples' University Federico II: Facilities, experimental tests, measurement systems
This work presents the main facilities of the Naples Towing Tank, LEIN: the instruments and the potential of the laboratory are presented, highlighting some strategies to resolve critical points typical of the towing tank tests. As example we point the attention on three aspects, typically critical: towing point of planing vessels, the accuracy of wave spectra generation and the settings of the radii of gyration for the seakeeping models
Clinical experience with pegylated hyaluronic acid fillers: A 3-year retrospective study
BACKGROUND: Hyaluronic acid fillers are the most used worldwide, thanks to the high biocompatibility and safety profile of HA and it is also the only substance that can be \u201cdissolved\u201d due to the hyaluronidase effect. AIM: A retrospective clinical evaluation of the outcomes following PEG cross-linked HA-based filler injection was performed. METHODS: Data were collected from December 2017 to June 2020. A total of 65 patients (12 M, 53 F), age ranging 28\u201362 year\u2019s old (mean age 42.3), were treated. Exclusion criteria were applied and in accord to treatment plan, were used specific site injections and fillers. Follow-up was evaluated between 6 months and 2 years. RESULTS: A total of 61 treatments using 124 vials of HA filler crosslinked with PEG were performed. CONCLUSION: In conclusion, from 2014, HA fillers having PEG as cross-linker agent have been introduced in the european market. Several papers have been published in order to evaluate the features of these fillers, although, to the best of our knowledge, this is the first clinical paper regarding their use
ATP precursor depletion and postischemic myocardial recovery
Although cardioplegia reduces myocardial metabolism during ischemia, adenosine triphosphate (ATP) depletion occurs, which may contribute to poor functional recovery after reperfusion. Augmenting myocardial adenosine during ischemia is successful in improving ATP repletion and myocardial recovery following ischemia. If adenosine is an important determinant of ischemic tolerance, then depletion or elimination of myocardial adenosine should lead to poor functional and metabolic recovery after ischemia. To test this hypothesis, isolated, perfused rabbit hearts were subjected to 120 min of 34[deg]C ischemia. Hearts received St. Thomas cardioplegia alone or cardioplegia containing 200 [mu]M adenosine, or cardioplegia containing 15, 5, 2.5, or 0.025 [mu]g/ml adenosine deaminase (ADA), which catalyzes the breakdown of adenosine to inosine, making adenosine unavailable as an ATP precursor. Functional recovery was determined and myocardial nucleotide levels were measured before, during, and after ischemia. Following ischemia and reperfusion, control hearts recovered to 51 +/- 3% of preischemic developed pressure (DP). There was significantly better recovery in adenosine-augmented hearts (68 +/- 7%), while ADA hearts had significantly worse recovery. Hearts treated with 0.025 [mu]g/ml ADA recovered to only 29 +/- 5% of DP and higher dose ADA hearts failed to demonstrate any recovery of systolic function. Furthermore, adenosine enhanced metabolic recovery, whereas ADA resulted in greatly depleted ATP and precursor reserves. Postischemic developed pressure closely paralleled the availability of myocardial adenosine, consistent with the hypothesis that myocardial adenosine levels at end ischemia and early reperfusion are important determinants of functional recovery after global ischemia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29313/1/0000378.pd
Source apportionment of PM10 in the Western Mediterranean based on observations from a cruise ship
Abstract Two intensive PM10 sampling campaigns were performed in the summers of 2009 and 2010 on the ship Costa Pacifica during cruises in the Western Mediterranean. Samples, mainly collected on an hourly basis, were analysed with different techniques (Particle Induced X-Ray Emission, PIXE; Energy Dispersive - X Ray Fluorescence, ED-XRF; Ion Chromatography, IC; Thermo-optical analysis) to retrieve the PM10 composition and its time pattern. The data were used for obtaining information about the sources of aerosol, with a focus on ship emissions, through apportionment using chemical marker compounds, correlation analysis and Positive Matrix Factorization (PMF) receptor modelling. For the campaign in 2010, 66% of the aerosol sulphate was found to be anthropogenic, only minor contributions of dust and sea salt sulphate were observed while the biogenic contribution, estimated based on the measurements of MSA, was found to be more important (26%), but influenced by large uncertainties. V and Ni were found to be suitable tracers of ship emissions during the campaigns. Four sources of aerosol were resolved by the PMF analysis; the source having the largest impact on PM10, BC and sulphate was identified as a mixed source, comprising emissions from ships. The correlations between sulphate and V and Ni showed the influence of ship emissions on sulphate in marine air masses. For the leg Palma–Tunis crossing a main ship route, the correlations between aerosol sulphate and V and Ni were particularly strong (r2 = 0.9 for both elements)
Fluctuating magnetic moments in liquid metals
We re-analyze literature data on neutron scattering by liquid metals to show
that non-magnetic liquid metals possess a magnetic moment that fluctuates on a
picosecond time scale. This time scale follows the motion of the cage-diffusion
process in which an ion rattles around in the cage formed by its neighbors. We
find that these fluctuating magnetic moments are present in liquid Hg, Al, Ga
and Pb, and possibly also in the alkali metals.Comment: 17 pages, 5 figures, submitted to PR
Which differences do elderly patients present in single-stage treatment for cholecysto-choledocholithiasis?
AbstractPatients with symptomatic gallstones present common bile duct stones in approximately 10% of cases. It is possible to resolve both gallbladder and bile duct stones with a single procedure. The aim of this study is to determine the effectiveness of a single stage procedure for gallbladder and bile duct stones in the elderly patients and to expose the differences between the various techniques. From January 2008 to December 2013, we treated 1540 patients with gallbladder stones. In 152 cases, we also found bile duct stones. 150 of these were treated in a single stage procedure. We divided our patients into 2 groups: Group A was younger than 65 (104 patients); Group B was 65 or older (46 patients). We retrospectively compared sex, ASA score, conversion rate, success rate, post-operative complications, hospital stay, and treatment method. We had no intra-operative mortality. 1 patient in Group B, heart condition (ASA 4), died with multiple organ failure (MOF) 10 days after his operation. ASA score: 3.5 ± 0.5 in A vs 2 ± 0.9 in B (P 0.001), post-operative complications 6% in A vs 18.1% in B (P 0.0325) and hospital stay 4.1 ± 2.3 in A vs 9.5 ± 5.5 in B (P 0.0001) were significantly higher in Group B. No differences were found in term of success rate: 94% in A vs 90% in B (P 0.4944). The procedure used to obtain the clearance of the bile duct showed a different success rate across the two groups: for the patients under 65 years old, trans-cystic clearance (TC-CBDE) was successful in 90% of cases, and only 51% for those older than 65, where we had to recall 49% for laparo-endoscopic rendez-vous (RV-IOERC) (P 0.0014). In conclusion, single stage treatment is safe and effective also to elderly patients. The methods used in patients being younger than 65 years old is what appeared to be significantly different
PM10 source apportionment based on PMF and chemical tracers during different cruises in Western Mediterranean
In the Western Mediterranean Basin, frequently exposed to high levels of air pollutants, an important source of pollution which influence the emission, is the intensive ship traffic. The Joint Research Centre of the European Commission (JRC, EC) has started a long-term monitoring program along different years over the Mediterranean Sea based on observations from a cruise ship following a regular route in the Western Mediterranean, in collaboration with the Department of Physics of University of Genoa. In this framework, an intensive PM10 sampling campaign was organized in the summer of 2011, in order to fill in the gap of data recovered (in term of PM speciation) during the previous campaigns (Schembari et al., 2014) and to get a better and complete description of PM sources. During this campaign the route of the ship was Civitavecchia-Savona-Barcelona-Palma de Mallorca- Malta (Valletta)-Palermo-Civitavecchia (see Figure 1). The PM samples were collected on Quartz and Teflon filters (47mm diameter, flow rate 2.3 m3/h) using in parallel two Sven Leckel Ingenieurburo sequential samplers, placed on the top of the cabin where the monitoring and meteorological station was located. Samples were analyzed with different techniques: Energy Dispersive X-Ray Fluorescence at the Department of Physics of Genoa (Ariola et al, 2006); Ion Chromatography (Chow and Watson, 1999) at Department of Chemistry of University of Milan; Thermo-optical analysis (Birch and Cary, 1996) at the JRC laboratory. Ion Beam Analysis measurements of the Teflon filters sampled during the week of September 2011, using simultaneously PIXE, EBS and PESA techniques (Chiari, 2005), were performed at the 3 MV Tandetron accelerator of the LABEC laboratory of INFN in Florence. The data were used to identify and characterize the main PM10 sources along the ship route, with a focus on ship emissions, through apportionment Positive Matrix Factorization receptor modelling, PMF (Paatero et al, 1994). Particular attention was given to the evidence of emissions from heavy fuel oil combustion by ships, known to be an important source of secondary sulphate aerosol. Five sources of aerosol were resolved by the PMF analysis with a new database. The analysis allows distinguishing between secondary and primary particle mass resulting from ship emissions: V and Ni were found to be suitable tracers of heavy fuel oil combustion source during the campaign. The source having the largest impact on PM10 was identified as Sulphate source by PMF. The correlations between Sulphate and V and Ni showed the influence of ship emissions on sulphate in marine air masses
Microscopic dynamics in liquid metals: the experimental point of view
The experimental results relevant for the understanding of the microscopic
dynamics in liquid metals are reviewed, with special regards to the ones
achieved in the last two decades. Inelastic Neutron Scattering played a major
role since the development of neutron facilities in the sixties. The last ten
years, however, saw the development of third generation radiation sources,
which opened the possibility of performing Inelastic Scattering with X rays,
thus disclosing previously unaccessible energy-momentum regions. The purely
coherent response of X rays, moreover, combined with the mixed
coherent/incoherent response typical of neutron scattering, provides enormous
potentialities to disentangle aspects related to the collectivity of motion
from the single particle dynamics.
If the last twenty years saw major experimental developments, on the
theoretical side fresh ideas came up to the side of the most traditional and
established theories. Beside the raw experimental results, therefore, we review
models and theoretical approaches for the description of microscopic dynamics
over different length-scales, from the hydrodynamic region down to the single
particle regime, walking the perilous and sometimes uncharted path of the
generalized hydrodynamics extension. Approaches peculiar of conductive systems,
based on the ionic plasma theory, are also considered, as well as kinetic and
mode coupling theory applied to hard sphere systems, which turn out to mimic
with remarkable detail the atomic dynamics of liquid metals. Finally, cutting
edges issues and open problems, such as the ultimate origin of the anomalous
acoustic dispersion or the relevance of transport properties of a conductive
systems in ruling the ionic dynamic structure factor are discussed.Comment: 53 pages, 41 figures, to appear in "The Review of Modern Physics".
Tentatively scheduled for July issu
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