765 research outputs found

    Surgical Treatment of Annuloaortic Ectasia - Replace or Repair?

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    Background: Patients with annuloaortic ectasia may be surgically treated with modified Bentall or David I valve-sparing procedures. Here, we compared the long-term results of these procedures. Methods: A total of 181 patients with annuloaortic ectasia underwent modified Bentall (102 patients, Group 1) or David I (79 patients, Group 2) procedures from 1994 to 2015. Mean age was 62 ± 11 years in Group? 1? and 64? ± 16 years in Group 2. Group 1 patients were in poorer health, with a lower ejection fraction and higher functional class. Results: Early mortality was 3% in Group 1 and 2.5% in Group 2. Patients undergoing a modified Bentall procedure had a higher incidence of thromboembolism and hemorrhage, whereas those undergoing a David I procedure had a higher incidence of endocarditis. Actuarial survival was 70 ± 6% at 15 years in Group 1 and 84 ± 7% at 10 years in Group 2. Actuarial freedom from reoperation was 97 ± 2% at 15 years in Group 1 and 84 ± 7% at 10 years in Group 2. In Group 2, freedom from procedure-related reoperations was 98 ± 2% at 10 years. At last follow-up, no cases of moderate or severe aortic regurgitation were observed. Conclusions: The modified Bentall and David I procedures showed excellent early and late results. The modified Bentall procedure with a mechanical conduit was associated with thromboembolic and hemorrhagic complications, whereas the David I procedure was associated with unexplained occurrences of endocarditis. Thus, the David I procedure appears to be safe, reproducible, and capable of achieving stable aortic valve repair and is therefore our currently preferred solution for patients with annuloaortic ectasia. However, the much shorter follow-up for David I patients limits the strength of our comparison between the two techniques

    Kinetic approaches to particle acceleration at cosmic ray modified shocks

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    Kinetic approaches provide an effective description of the process of particle acceleration at shock fronts and allow to take into account the dynamical reaction of the accelerated particles as well as the amplification of the turbulent magnetic field as due to streaming instability. The latter does in turn affect the maximum achievable momentum and thereby the acceleration process itself, in a chain of causality which is typical of non-linear systems. Here we provide a technical description of two of these kinetic approaches and show that they basically lead to the same conclusions. In particular we discuss the effects of shock modification on the spectral shape of the accelerated particles, on the maximum momentum, on the thermodynamic properties of the background fluid and on the escaping and advected fluxes of accelerated particles.Comment: 22 pages, 7 figures, accepted for publication in MNRA

    Implications of a Nonthermal Origin of the Excess EUV Emission from the Coma Cluster of Galaxies

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    The inverse Compton (IC) interpretation of the excess EUV emission, that was recently reported from several clusters of galaxies, suggests that the amount of relativistic electrons in the intracluster medium is highly significant, W_e>10^{61} erg. Considering Coma as the prototype galaxy cluster of nonthermal radiation, we discuss implications of the inverse Compton origin of the excess EUV fluxes in the case of low intracluster magnetic fields of order 0.1 muG, as required for the IC interpretation of the observed excess hard X-ray flux, and in the case of high fields of order 1 muG as suggested by Faraday rotation measurements. Although for such high intracluster fields the excess hard X-rays will require an explanation other than by the IC effect, we show that the excess EUV flux can be explained by the IC emission of a `relic' population of electrons driven into the incipient intracluster medium at the epoch of starburst activity by galactic winds, and later on reenergized by adiabatic compression and/or large-scale shocks transmitted through the cluster as the consequence of more recent merger events. For high magnetic fields B > 1 muG the interpretation of the radio fluxes of Coma requires a second population of electrons injected recently. They can be explained as secondaries produced by a population of relativistic protons. We calculate the fluxes of gamma-rays to be expected in both the low and high magnetic field scenarios, and discuss possibilities to distinguish between these two principal options by future gamma-ray observations.Comment: LaTeX, 6 figures; accepted for publication in Ap

    THU0366 SYSTEMATIC CORONARY RISK EVALUATION (SCORE) MISCLASSIFIES CARDIOVASCULAR RISK IN ANTISYNTHETASE SYNDROME: RESULTS OF THE PILOT MULTICENTRIC STUDY RI.CAR.D.A.

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    Background:Antisynthetase Syndrom (ASyS) is an autoimmune overlap disease characterized by antiaminoacyl-tRNA-synthetase (anti-ARS) antibodies and the classic triad of arthritis, myositis and interstitial lung disease (ILD) (1). Markers of cardiovascular (CV) or cerebrovascular (CVB) risk have never been examined in ASyS.Objectives:Aim of this study (RIsk of CARdiovascular Disease in ASyS: RI.CAR.D.A.) was to test the ability of an established traditional CV risk prediction score (Systematic Coronary Risk Evaluation-SCORE) and its EULAR modified version (mSCORE) to identify ASyS patients at high CV risk. Moreover, we sought to examine for the first time associations of CV surrogate markers with clinical and immunological ASyS parameters.Methods:SCORE/mSCORE and the gold standard marker of aortic stiffness (carotid-femoral pulse wave velocity-cfPWV) were examined in patients with ASyS and healthy controls in a multicenter setting (6 Rheumatology Centers). Moreover, sonography of the common- (CCA), internal- (ICA) and external- (ECA) carotid arteries was performed in subsets of both groups, evaluating carotid intima-media-thickness (cIMT), plaques and duplex-sonographic indices of CBV risk such as the resistance- (RI) and pulsatility-index (PI).Figure 1.Carotid Doppler surrogate markers of cardiovascular and cerebrovascular risk in controls and ASyS (case).cIMTCarotid intima media thickness;CAA(common-),ICA(internal),ECA(external) carotid artery;RIresistance index;PIpulsatility index. (all;p0.9 mm) (SCA) in85.7%of the patients respectively. ROC analyses showed similarly poor diagnostic performances of SCORE/mSCORE in comparison to cfPWV(>10 m/s) and SAC by areas under the curve (AUC) of0.56 (95%CI=0.39-0.73) and0.63 (95%CI=0.3-0.96),respectively. cfPWV and SCA were higher in ASyS patients compared to controls (padj=0.021andp=0.003, respectively). cfPWV and cIMT correlated in the patient group significantly with age (r=0.679; p<0.001 and r=0.664; p<0.001,respectively).Moreover, cfPWV correlated with BMI (padj=0.001) and diabetes(padj=0.043). ACC-RI and ACC-PI showed significant associations with a marker of myositis activity [creatine phosphokinase (CPK):r=0.629;p=0.012andr=0.574;p=0.032, respectively]. Finally, ACI-RI and ACI-PI values were higher in patients with ILD (both;p=0.039).Conclusion:This is the first report of higher aortic stiffness and SCA in ASyS patients compared to controls. Active myositis and presence of ILD were associated with higher CVB risk parameters. Furthermore, SCORE/mSCORE performed poorly in identifying patients at high CV risk and carotid arteriosclerosis compared to cfPWV and CS respectively. Thus, cfPWV and CS could improve CV and CBV screening in ASyS patients.References:[1]Cavagna L, et al. Clinical Spectrum Time Course in Anti Jo-1 Positive Antisynthetase Syndrome.Medicine2015;94:1144.Disclosure of Interests:None declare

    Topological Vector Symmetry of BRSTQFT and Construction of Maximal Supersymmetry

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    The scalar and vector topological Yang-Mills symmetries determine a closed and consistent sector of Yang-Mills supersymmetry. We provide a geometrical construction of these symmetries, based on a horizontality condition on reducible manifolds. This yields globally well-defined scalar and vector topological BRST operators. These operators generate a subalgebra of maximally supersymmetric Yang-Mills theory, which is small enough to be closed off-shell with a finite set of auxiliary fields and large enough to determine the Yang-Mills supersymmetric theory. Poincar\'e supersymmetry is reached in the limit of flat manifolds. The arbitrariness of the gauge functions in BRSTQFTs is thus removed by the requirement of scalar and vector topological symmetry, which also determines the complete supersymmetry transformations in a twisted way. Provided additional Killing vectors exist on the manifold, an equivariant extension of our geometrical framework is provided, and the resulting "equivariant topological field theory" corresponds to the twist of super Yang-Mills theory on Omega backgrounds.Comment: 50 page

    Evaluation of Biological Response of STRO-1/c-Kit Enriched Human Dental Pulp Stem Cells to Titanium Surfaces Treated with Two Different Cleaning Systems.

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    Peri-implantitis-an infection caused by bacterial deposition of biofilm-is a common complication in dentistry which may lead to implant loss. Several decontamination procedures have been investigated to identify the optimal approach being capable to remove the bacterial biofilm without modifying the implant surface properties. Our study evaluated whether two different systems-Ni-Ti Brushes (Brush) and Air-Polishing with 40 \ub5m bicarbonate powder (Bic40)-might alter the physical/chemical features of two different titanium surfaces-machined (MCH) and Ca++ nanostructured (NCA)-and whether these decontamination systems may affect the biological properties of human STRO-1+/c-Kit+ dental pulp stem cells (hDPSCs) as well as the bacterial ability to produce biofilm. Cell morphology, proliferation and stemness markers were analysed in hDPSCs grown on both surfaces, before and after the decontamination treatments. Our findings highlighted that Bic40 treatment either maintained the surface characteristics of both implants and allowed hDPSCs to proliferate and preserve their stemness properties. Moreover, Bic40 treatment proved effective in removing bacterial biofilm from both titanium surfaces and consistently limited the biofilm re-growth. In conclusion, our data suggest that Bic40 treatment may operatively clean smooth and rough surfaces without altering their properties and, consequently, offer favourable conditions for reparative cells to hold their biological properties

    Probing mSUGRA via the Extreme Universe Space Observatory

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    An analysis is carried out within mSUGRA of the estimated number of events originating from upward moving ultra-high energy neutralinos that could be detected by the Extreme Universe Space Observatory (EUSO). The analysis exploits a recently proposed technique that differentiates ultra-high energy neutralinos from ultra-high energy neutrinos using their different absorption lengths in the Earth's crust. It is shown that for a significant part of the parameter space, where the neutralino is mostly a Bino and with squark mass 1\sim 1 TeV, EUSO could see ultra-high energy neutralino events with essentially no background. In the energy range 10^9 GeV < E < 10^11 GeV, the unprecedented aperture of EUSO makes the telescope sensitive to neutralino fluxes as low as 1.1 \times 10^{-6} (E/GeV)^{-1.3} GeV^{-1} cm^{-2} yr^{-1} sr^{-1}, at the 95% CL. Such a hard spectrum is characteristic of supermassive particles' NN-body hadronic decay. The case in which the flux of ultra-high energy neutralinos is produced via decay of metastable heavy particles with uniform distribution throughout the universe is analyzed in detail. The normalization of the ratio of the relics' density to their lifetime has been fixed so that the baryon flux produced in the supermassive particle decays contributes to about 1/3 of the events reported by the AGASA Collaboration below 10^{11} GeV, and hence the associated GeV gamma-ray flux is in complete agreement with EGRET data. For this particular case, EUSO will collect between 4 and 5 neutralino events (with 0.3 of background) in ~ 3 yr of running. NASA's planned mission, the Orbiting Wide-angle Light-collectors (OWL), is also briefly discussed in this context.Comment: Some discussion added, final version to be published in Physical Review

    TeV Particle Astrophysics II: Summary comments

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    A unifying theme of this conference was the use of different approaches to understand astrophysical sources of energetic particles in the TeV range and above. In this summary I review how gamma-ray astronomy, neutrino astronomy and (to some extent) gravitational wave astronomy provide complementary avenues to understanding the origin and role of high-energy particles in energetic astrophysical sources.Comment: 6 pages, 4 figures; Conference summary talk for "TeV Particle Astrophysics II" at University of Wisconsin, Madison, 28-31 August 200
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