30 research outputs found
Carleson measures for the Drury–Arveson Hardy space and other Besov–Sobolev spaces on complex balls
No full textAbstractFor 0⩽σ<1/2 we characterize Carleson measures μ for the analytic Besov–Sobolev spaces B2σ on the unit ball Bn in Cn by the discrete tree condition∑β⩾α[2σd(β)I*μ(β)]2⩽CI*μ(α)<∞,α∈Tn, on the associated Bergman tree Tn. Combined with recent results about interpolating sequences this leads, for this range of σ, to a characterization of universal interpolating sequences for B2σ and also for its multiplier algebra.However, the tree condition is not necessary for a measure to be a Carleson measure for the Drury–Arveson Hardy space Hn2=B21/2. We show that μ is a Carleson measure for B21/2 if and only if both the simple condition2d(α)I*μ(α)⩽C,α∈Tn, and the split tree condition∑k⩾0∑γ⩾α2d(γ)−k∑(δ,δ′)∈G(k)(γ)I*μ(δ)I*μ(δ′)⩽CI*μ(α),α∈Tn, hold. This gives a sharp estimate for Drury's generalization of von Neumann's operator inequality to the complex ball, and also provides a universal characterization of Carleson measures, up to dimensional constants, for Hilbert spaces with a complete continuous Nevanlinna–Pick kernel function.We give a detailed analysis of the split tree condition for measures supported on embedded two manifolds and we find that in some generic cases the condition simplifies. We also establish a connection between function spaces on embedded two manifolds and Hardy spaces of plane domains
Markers of coronary damage. From diagnosis to prognosis
No full textCardiovascular disease is a major public health problem, Rapid and accurate diagnosis in the
emergency department is essential for timely initiation oftreatment, thus any means for improving
the speed and accuracy of acute coronary syndrome (ACS) diagnosis can contribute to better
clinical and economi c outcomes. Measurement of circulating level of troponin has proven to be a
sensitive and specific test for cardiac damage detection but they do not discriminate between
ischemic and not ischemic etiologies of'rnyocardial injury. Combining troponin with other cardiac
biomarkers may offer complimentary information on the underlying pathobiology and prognosis in
an individual patient, may increase the analytic sensitivity for myocardial damage and offer insights
into the timing and mechanism of myocardial injury. Several prospective epidemiological studies
have documented an association between inflammatory markers and cardiovascular disease and
their role in primary and secondary prevention and as predictor of mortality. OBJECTIVE: We
sought to report a selected but representative evidence on some new biological markers of cardiac
damage, ineluding inflammatory cytokines in patients with cardiovascular disease. DATA
SOURCES: We searched in Medline from January 1998 to March 2005 for all studies focusing on
the diagnostic and prognostic value of new markers of cardiac damage in patients with ACS and
heart failure. CONCLUSION: The use ofnecrotic markers to risk stratify patients with chest pain
has become an established practice in the clinical setting while the role of other inflammatory
biomarkers, despite being still undefined, seems promising under both pathophysiologic and
prognostic perspective
The control of catalytic performance of rutile-type Sn/V/Nb/Sb mixed oxides, catalysts for propane ammoxidation to acrylonitrile
No full textArcozzi, Elena Ballarini, Nicola Cavani, Fabrizio Cimini, Massimo Lucarelli, Carlo Trifiro, Ferruccio Delichere, Pierre Millet, Jean-Marc M. Marion, PhilippeInternational audienceThis paper describes the effect of the composition of rutile-type Sn/V/Nb/Sb mixed oxides catalysts on the catalytic performance in the gas-phase ammoxidation of propane to acrylonitrile. The variation in the atomic ratio between components in catalysts is the key for the control of activity and selectivity. In samples with atomic composition Sn/V/Nb/Sb 1/0.2/1/x (0 <= x <= 5) and 1/0.2/y/3 (0 <= y <= 3) several compounds formed, i.e., SnO2, Sb/Nb mixed oxide, Sb6O13 and non-stoichiometric rutile-type V/Nb/Sb/O; the latter segregated preferentially at the surface of the catalyst. Tin oxide provided the rutile matrix for the dispersion of the mixed oxides. The main role of Sb was shown to generate mixed oxides containing specific sites for the allylic ammoxidation of propylene intermediately formed. The presence of Nb enhanced the activity and selectivity of these sites. (C) 2008 Elsevier B.V. All rights reserved
The 5-Year Clinical Outcomes After a Randomized Comparison of Sirolimus-Eluting Versus Bare-Metal Stent Implantation in Patients With ST-Segment Elevation Myocardial Infarction
No full textBecause patients with acute ST-segment elevation
myocardial infarction (STEMI) were excluded from early randomized
trials, only relatively short-term data from large multicenter studies
comparing drug-eluting stents (DES) with bare-metal stents (BMS) are
currently available. Unambiguous ascertainment of long-term compliance
with thienopyridines is problematic in STEMI, which is a matter of
serious concern (1,2), and one observational registry suggested higher late
(6 months) unadjusted and adjusted mortality rates in STEMI patients
with a DES compared with those with a BMS (3). Thus, the use of a
DES in STEMI patients still remains highly controversial.
The design of the study and outcomes at 8- and 24-month
follow-up were previously reported (4,5). Since then, all eligible
patients underwent routine clinical follow-up at 6-month intervals for
5 years after index intervention. All events up to 5 years were
adjudicated by an independent clinical event committee that was
blinded to the treatment assignments.
All analyses were conducted according to the intent-to-treat
principle. Event-free survival curves were generated using the Kaplan-
Meier method, and survival between groups was compared using the
log-rank test. Hazard ratios (HRs) with 95% confidence intervals
(CIs) were calculated using the Cox proportional hazards model.
The cumulative duration of dual antiplatelet treatment trended
longer in the tirofiban–sirolimus-eluting stent (SES) arm (182 92
days vs. 155 105 days in the abciximab BMS group; p 0.073);
however, 80% and 100% of patients in both groups discontinued
thienopyridines after 250 days and 360 days, respectively. Overall, use
of medications did not differ between study groups at any time point
during follow-up. Complete follow-up information for as long as
1,800 days was available for all patients.
At 5 years, the cumulative incidence of major adverse cardiac
events (MACE) (death, myocardial infarction [MI], or target
vessel revascularization) trended lower in the tirofiban-SES group
(29.9% vs. 43.2%; HR: 0.63 [95% CI: 0.39 to 1.03]; p 0.067)
(Fig. 1A). All-cause mortality (18.4%; 95% CI: 12% to 28%) (Fig.
1A) and the composite of death or MI (21.8%; 95% CI: 14% to 32%)
(Fig. 1B) were similar in the tirofiban-SES versus the abciximab-
BMS group (15.9%; 95% CI: 10% to 25%, p 0.70 and 25.0%; 95%
CI: 17% to 35%, p 0.58, respectively), whereas the need for target
vessel revascularization remained markedly reduced (10.3% vs. 26.1%;
HR: 0.37 [95% CI: 0.17 to 0.79]; p 0.007) in the tirofiban-SES
group (Fig. 1C).
The cumulative incidence of definite, probable, or possible stent
thrombosis was 6.9% versus 7.9% in the tirofiban-SES group and
abciximab-BMS group, respectively (HR: 0.86 [95% CI: 0.29 to 2.6];
p 0.78 (Fig. 1B). The cumulative incidence of definite and definite
or probable stent thrombosis also did not differ between the 2 groups.
Among patients who were alive at 12 months, the cumulative
incidence of death or nonfatal MI at 5 years was 11.2% in the
tirofiban-SES group and 10% in the abciximab-BMS group (p
0.80 at log-rank test). Finally, excluding patients who underwent
target vessel revascularization between 30 days and 1 year after the
index procedure, the cumulative incidence of death or nonfatal MI at
5 years was 21.5% in the tirofiban-SES and 24.7% in the abciximab-
BMS group (p 0.78 at log-rank test), whereas the incidence of
death or nonfatal MI at 5 years in patients who survived the first year
follow-up free from target vessel revascularization was 9.7% in the
tirofiban-SES group and 9.2% in the abciximab-BMS group (p
0.88; log-rank test).
Although it was open label and single center, our study is the
first randomized controlled investigation of DES versus BMS
implantation in the setting of STEMI patients undergoing mechanical
intervention.
A maintained clinical benefit for 24 months in terms of
reintervention in the previously instrumented artery with no excess
of subacute or late stent thrombosis was previously reported (5,6).
The current report extends these findings to 5-year follow-up.
Although results from randomized controlled trials are still pending
(7), expert consensus recommends prolonging treatment with
aspirin and thienopyridines for at least 1 year after DES placement.
Importantly, our study was conceived and conducted well before
unambiguous safety issues for DES use were raised. As a consequence,
only relatively short duration of dual antiplatelet treatment (i.e., a
minimum of 3 months) was protocol mandated. Accordingly, approximately
one-half of the patients discontinued thienopyridines by 6
months after intervention and nearly all discontinued dual antiplatelet
treatment at 1 year. Thus, long-term follow-up of this study is critical
to shed light on the safety profile of SES implantation followed by a
relatively short combined antiplatelet regimen in unselected patients
undergoing intervention for STEMI, a currently off-label indication.
At 5-year follow-up, the cumulative incidence of death or nonfatal
MI remained similar in the 2 study groups, and this held true at
landmark analysis of patients alive at 12-month follow-up. Based on
a broad clinical definition of stent thrombosis, namely, the Academic
Research Consortium classification, we likewise failed to observe an
excess of late events in those patients assigned to receive SES
implantation, whereas the benefit in terms of reintervention persisted
almost unchanged after 1,800 days with no evidence of a late catch-up
phenomenon. This is in keeping with the long-term results of the
landmark randomized studies that led to DES approval, whereas it
contrasts with recent data from observational studies on acute MI
patients that questioned the long-term durability of DES benefit in
this patient/lesion subset (3,8)
Effect of thienopyridines discontinuation on mortality or MI after SES versus BMS implantation in STEMI
No full text
The cut locus of a C^2 surface in the Heisenberg group
No full textMy master thesis deals with some fine properties of the natural Carnot-Carathéodory distance in the Heisenberg group. In particular, we are interested in properties related to the cut locus of a smooth surface (for us, the term smooth indicates a second order differentiability). The cut locus of a closed subset S of the n-dimensional Euclidean space, denoted by cut(S), is the set containing the endpoints of maximal segments that minimize the distance to S. In the Euclidean case many properties of the cut locus are well known if S is the smooth boundary of an open set. For example the cut loci of such surfaces are closed (this is the fact we will be most interested in). Such results are still valid if the Euclidean metric is replaced with any smooth Riemannian metric.
Not all the known properties of the cut locus in Riemannian geometry are also known to hold in the sub-Riemannian case. So our goal is to generalize and prove some of them in the Heisenberg group, which has the simplest sub-Riemannian structure. In particular we are very interested in proving that the cut loci of surfaces which are the smooth boundary of open sets in the Heisenberg group are closed sets.
At the moment we are not able to give a proof of the closure of the cut locus. So we are looking for new properties of the Carnot distance which may be related with the cut locus of a smooth surface in the Heisenberg group and that may be useful to prove its closure. Precisely, we are investigating in points conjugate to the surface S, since they are strictly connected with the cut locus in the Riemannian case. Just about conjugate points, we will show some new small results at the end of this work
Homeomorphic extension of Quasi-Isometries and Iteration Theory
No full textStarting from the Riemann Mapping Theorem it arises the interest for
biholomorphisms over domains in one or several complex variables. Poincar´e
showed that there is no analytic isomorphism between the Polydisc and the
unit ball already in C^2. The previous fact may suggest that biholomorphic
domains are a class of such well-behaved sets that could extend some regularity of the biholomorpshism until their respective boundaries. A very influent
approach was faced by Fefferman (published in the year 1974), by
proving that every biholomorphism between bounded strongly pseudoconvex
domains with
smooth boundaries extends as a diffeomorphism to the closures of the domains. In this work is quoted a classical result that presents
an isometry respect to the Bergman metric between biholomorphic domains
and he noticed an interesting behaviour of geodesics when they are going to
the boundary of a considered domain.
The first part of this thesis mainly follows Abate’s work aiming to show the homeomorphic extension of a biholomorphism between C^2-smooth strongly pseudoconvex domains.
The second part of this thesis mainly follows the work of Bracci, Gaussier and
Zimmer aiming to show the homeomorphic extension of a Quasi-Isometric homeomorphisms to the End compactifications of the respective domains.
Other consequences are related to extend the Denjoy-Wolff
Theorem for domains in several complex variables and present the Denjoy-Wolff behaviour
for commuting holomorphic selfmaps with no fixed point in the domain itself
Tissue Factor and Coagulation Factor VII Levels during Acute Myocardial Infarction Contribute to Predict Mortality and re-infarction.
No full textA strategy to offset the extra cost of sirolimus-eluting stent in patients undergoing intervention for acute myocardial infarction
No full textObjective: To obtain a quantitative estimate of the overall costs and cost effectiveness ratio of sirolimus-eluting stents (SES) implantation and
tirofiban infusion compared to abciximab and bare metal stent (BMS) in patients undergoing primary intervention for acute ST segment
elevation myocardial infarction (STEMI).
Methods: In the attempt to make the unrestricted use of SES in STEMI patients affordable under the current European reimbursement system,
between March 6, 2003, and April 23, 2004, 175 patients with STEMI were randomized to receive tirofiban infusion and SES versus
abciximab and BMS as part of the STRATEGY trial. Costs and outcome were monitored for 2 years.
Results: The cost of the index procedure was €9345±2573 and €9657±2114 for the tirofiban+SES and abciximab+BMS group,
respectively (P=0.048). At follow-up, the composite of death or myocardial infarction and the costs not related to target vessel
revascularisation (TVR) did not differ in the two groups while the rate of TVR and the costs related to it were lower in the tirofiban+SES
group. The overall 2-year cost of treating a patient in the tirofiban+SES group was €10,971±4185 compared to €12,066±4636 for the
abciximab+BMS group (P=0.006). Halving the cost of abciximab resulted in higher initial hospital costs for the tirofiban+SES but overall
cost neutrality over a 24-month time horizon.
Conclusions: Compared to abciximab+BMS, tirofiban infusion+SES implantation in STEMI patients was an economically dominant
strategy, with an improved composite outcome and lower overall costs
