Estimating observables from conditioned dynamics is typically computationally hard. While obtaining independent samples efficiently from unconditioned dynamics is usually feasible, most of them do ...not satisfy the imposed conditions and must be discarded. On the other hand, conditioning breaks the causal properties of the dynamics, which ultimately renders the sampling of the conditioned dynamics non-trivial and inefficient. In this work, a Causal Variational Approach is proposed, as an approximate method to generate independent samples from a conditioned distribution. The procedure relies on learning the parameters of a generalized dynamical model that optimally describes the conditioned distribution in a variational sense. The outcome is an effective and unconditioned dynamical model from which one can trivially obtain independent samples, effectively restoring the causality of the conditioned dynamics. The consequences are twofold: the method allows one to efficiently compute observables from the conditioned dynamics by averaging over independent samples; moreover, it provides an effective unconditioned distribution that is easy to interpret. This approximation can be applied virtually to any dynamics. The application of the method to epidemic inference is discussed in detail. The results of direct comparison with state-of-the-art inference methods, including the soft-margin approach and mean-field methods, are promising.
In this paper, a biobased binder mainly composed of polylactic acid (PLA) was developed for the production of Ti6Al4V feedstock suitable for 3D printing via material extrusion. 3D printed samples ...were debound via solvent and thermal treatments and successfully sintered in reducing atmosphere obtaining dense metallic components. The designed and produced bio-binder is completely eliminated during the debinding processes leading to sintered samples showing a high densification (93–94%), with a microstructure composed of primary alpha phase with segregated beta phase at grain boundaries and having average grain size of 70 μm. 3D printed sintered samples show good mechanical properties (yield strength (σy) = 662 MPa, ultimate tensilte strength (UTS) = 743 MPa, elongation at break (εmax) = 12%, hardness = 5.15 GPa) influenced by the sintering parameters and the presence of some degree of micro-porosity in the final structure.
The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave ...excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.
Abstract Background Elderly patients display higher on clopidogrel platelet reactivity as compared to younger patients. Treatment with prasugrel 5 mg has been shown to provide more predictable and ...homogenous antiplatelet effect, as compared to clopidogrel, suggesting the possibility of reducing ischemic events after an acute coronary syndrome (ACS) without increasing bleeding. Study design The Elderly-ACS 2 study is a multicenter, randomized, parallel-group, open-label trial designed to demonstrate the superiority of a strategy of dual antiplatelet treatment using a reduced 5 mg daily dose of prasugrel over a standard strategy with a daily clopidogrel dose of 75 mg in patients >74 years of age with ACS (either ST- or non ST-elevation myocardial infarction) undergoing early percutaneous revascularization. The primary endpoint is the composite of all-cause mortality, myocardial re-infarction, disabling stroke and re-hospitalization for cardiovascular causes or bleeding within one year. Taking advantage of the planned size of 2000 patients, the secondary objective is to assess the prognostic impact of selected pre-randomization variables (age, sex, diabetic status, serum creatinine level, ECG changes, abnormal troponin levels, basal and residual SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery SYNTAX score). Conclusion The Elderly-ACS 2 study is a multicenter, randomized trial comparing a strategy of dual antiplatelet therapy with a reduced dose of prasugrel with a standard dose of clopidogrel in elderly patients with ACS undergoing percutaneous revascularization. (The Elderly ACS 2 trial: NCT01777503 )
Continuous venovenous hemofiltration (CVVH) is a renal replacement therapy that has been successfully used in patients with severe chronic renal failure to prevent contrast-induced acute kidney ...injury (CI-AKI). In this study, we present a consecutive experience using a new CVVH protocol that has also been applied to patients with acute coronary syndrome (ACS). CVVH was performed in consecutive patients with estimated glomerular filtration rate <30 ml/min/1.73 m2 (mean ± SD, 21.1 ± 7.3 ml/min/1.73 m2 ) undergoing diagnostic or interventional coronary procedures starting after the angiographic procedures. Iopamidol was used as a contrast agent. In the first 6 patients, iopamidol removal by the CVVH hemofilter and kidney was calculated by measuring iopamidol concentrations in the blood, urine, and ultrafiltrate collected during the 6-hour CVVH session. In the second phase, the protocol was applied to 47 additional patients meeting the inclusion criteria. Six-hour CVVH resulted in iopamidol removal comparable with that of 12-hour diuresis (43 ± 12% vs 42 ± 15% of administered, p = NS). CI-AKI occurred in 7.5% of patients in the whole population and no patients had acute pulmonary edema, need for dialysis, or any major bleeding. In conclusion, in a population including patients with ACS with severe chronic renal failure undergoing coronary angiographic procedures, 6-hour CVVH performed only after contrast medium exposure was able to remove an amount of contrast medium similar to that removed by the kidneys in 12 hours and resulted in a low rate of CI-AKI.
The residual burden of coronary artery disease after percutaneous coronary intervention (PCI) has been associated with worse ischemic outcome. However, data are conflicting in elderly patients. The ...aim of our study was to verify the incremental value of the residual Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) score (rSS) over clinical variables and baseline SYNTAX score (bSS) in predicting 1-year mortality or cardiovascular events.
A post hoc analysis of data collected in the Elderly-ACS 2 multicenter randomized trial was performed. We included 630 patients aged > 75 years with multivessel coronary disease undergoing PCI for acute coronary syndrome (ACS). The primary outcome was a composite of death, recurrent myocardial infarction, and stroke at 1-year follow up. Change in c-statistic and standardized net benefit were used to evaluate the incremental value of the rSS.
Event rates were significantly higher in patients with incomplete revascularization (rSS > 8). When the rSS was included in a core Cox regression model containing age, previous myocardial infarction, and ACS type, the hazard ratio for patients with score values > 8 was 2.47 (95% confidence interval, 1.51-4.06). However, the core model with rSS did not increase the c-statistic compared with the core model with the bSS (from 0.69 to 0.70) and gave little incremental value in the standardized net benefit.
In elderly patients with ACS with multivessel disease undergoing PCI, incomplete revascularization was associated with worse outcome at 1-year follow-up. However, there was no clear incremental value of the rSS in the prediction of 1-year adverse outcome compared with a model including clinical variables and bSS.
Le fardeau résiduel de la coronaropathie après une intervention coronarienne percutanée (ICP) a été associé à de moins bons résultats sur le plan ischémique. Les données recueillies chez les patients âgés sont toutefois contradictoires. Cette étude avait donc pour objectif de valider la valeur ajoutée du score SYNTAX (SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery) résiduel (SSr) par rapport aux paramètres cliniques et au score SYNTAX initial (SSi) pour prédire la mortalité à 1 an et les manifestations cardiovasculaires.
Une analyse a posteriori des données de l’étude multicentrique avec répartition aléatoire Elderly-ACS 2 a été effectuée. Pour ce faire, 630 patients âgés de plus de 75 ans, atteints d’une coronaropathie multitronculaire et ayant subi une ICP pour traiter un syndrome coronarien aigu (SCA) ont été retenus. Le critère d’évaluation principal était composé du décès, de l’infarctus du myocarde récurrent et de l’accident vasculaire cérébral (AVC) au moment du suivi à 1 an. La variation de la statistique C et le bénéfice net normalisé ont servi à évaluer la valeur ajoutée du SSr.
Les manifestations étaient significativement plus fréquentes chez les patients dont la revascularisation était incomplète (SSr > 8). Lorsque le SSr a été pris en compte dans un modèle de régression de Cox de base ayant pour facteurs l’âge, les antécédents d’infarctus du myocarde et le type de SCA, le rapport des risques instantanés pour les patients ayant un score > 8 était de 2,47 (intervalle de confiance à 95 % : 1,51-4,06). L’intégration du SSr dans le modèle de base n’a toutefois pas donné lieu à une statistique C plus élevée que celle du SSi (0,70 vs 0,69) et conférait peu de valeur ajoutée sur le plan du bénéfice net normalisé.
Chez les patients âgés présentant un SCA et une atteinte multitronculaire, et subissant une ICP, la revascularisation incomplète a été associée à de moins bons résultats au moment du suivi à 1 an. Le SSr n’a toutefois pas été clairement associé à une valeur ajoutée pour prédire une issue défavorable à 1 an comparativement à un modèle reposant sur des paramètres cliniques et le SSi.
In this paper, a formaldehyde-free copper electroless plating process was optimized using statistical analysis (Design of Experiment) in order to maximize the adhesion and the electrical conductivity ...when deposited on carbon-epoxy substrates. The coatings' morphologies, the electrical resistance, and the adhesion vary significantly as function of electroless plating parameters, but among the selected processing parameters, (pH of the electroless solution, temperature, concentration of reducing agent (glyoxylic acid), and concentration of complexing agent (EDTA)) only the temperature and the concentration of the reducing agent resulted to be influencing factors for the deposition process. A multi-objective optimization approach allowed to set the electroless process parameters in order to obtain optimized coatings presenting improved adhesion (scratch test’s critical load CL3 > 30 N) and electrical conductivity (Rs = 1.91 × 10
–2
Ω/sq).
In this paper self-sensing nanocomposite formulations made of acrylonitrile butadiene styrene and different loading (3, 5 and 10 wt%) of multi-walled carbon nanotubes have been produced and 3D ...printed via fused filament fabrication. The nanocomposites have been characterized from a rheological, mechanical, thermal and electrical point of view to assess the strain-sensing properties. All the samples show a piezoresistive behaviour and the electrical resistance changes when a stress is applied. The gauge factor, measure of the sensitivity, for ABS 3CNT, ABS 5CNT and ABS 10CNT are 11.36, 3.21 and 1.62, respectively. The ABS 3CNT samples have shown the best self-sensing performances with high sensitivity and this formulation has been used for producing a health-monitoring 3D-printed smart structure where the active material is placed locally in the structure. The 3D-printed structure itself is able to monitor the strain and hence the stress level to which is subjected with a gauge factor of 1.5. A finite element analysis helps to explain the reason for reduced sensitivity namely the placement of the sensing layer.
Abstract Objectives The aim of this study was to investigate the association between high on-treatment platelet reactivity (HPR) and the SYNTAX (Synergy Between Percutaneous Coronary Intervention ...With Taxus and Cardiac Surgery) score (SS) for risk prediction of major adverse cardiovascular events (MACE) in patients with non–ST-segment elevation acute coronary syndrome (NSTEACS) undergoing percutaneous coronary intervention (PCI). Background Platelet function testing may be used to optimize antiplatelet therapy in high-risk patients, but identification of this category of patients remains challenging. Methods The GEPRESS (Gene Polymorphism, Platelet Reactivity, and the Syntax Score) study was a prospective, multicenter, observational study enrolling 1,053 patients with NSTEACS undergoing PCI and treated with clopidogrel. The platelet reactivity index (PRI) was measured at 3 time points: before PCI, at hospital discharge, and 1 month after PCI. Genetic variants of clopidogrel metabolism were determined in 750 patients. Patients were stratified by the presence of HPR (PRI >50%) and by tertile of the SS (upper SS tertile ≥15). The primary objective of this study was the risk of MACE in the period between 1 month and 1 year. Results Between 1 month and 1 year, 1-month HPR was an independent predictor of MACE in patients with an SS ≥15, but not in those with an SS <15, displaying a 5-fold increase in event rates (10.4% vs. 2.5%; p < 0.0001). CYP2C19*2 was the only single nucleotide polymorphism associated with HPR, but it was not associated with MACE. Although there was a significant variability in the PRI across the 1-month period, predischarge HPR and SS effectively stratified the risk of subsequent MACE up to 1-year follow-up. Conclusions In clopidogrel-treated patients with NSTEACS undergoing PCI, HPR was independently associated with an increased risk of MACE only in the presence of a high SS.
We investigate the information-theoretical limits of inference tasks in epidemic spreading on graphs in the thermodynamic limit. The typical inference tasks consist in computing observables of the ...posterior distribution of the epidemic model given observations taken from a ground-truth (sometimes called planted) random trajectory. We can identify two main sources of quenched disorder: the graph ensemble and the planted trajectory. The epidemic dynamics however induces nontrivial long-range correlations among individuals' states on the latter. This results in nonlocal correlated quenched disorder which unfortunately is typically hard to handle. To overcome this difficulty, we divide the dynamical process into two sets of variables: a set of stochastic independent variables (representing transmission delays), plus a set of correlated variables (the infection times) that depend deterministically on the first. Treating the former as quenched variables and the latter as dynamic ones, computing disorder average becomes feasible by means of the replica-symmetric cavity method. We give theoretical predictions on the posterior probability distribution of the trajectory of each individual, conditioned to observations on the state of individuals at given times, focusing on the susceptible infectious (SI) model. In the Bayes-optimal condition, i.e., when true dynamic parameters are known, the inference task is expected to fall in the replica-symmetric regime. We indeed provide predictions for the information theoretic limits of various inference tasks, in form of phase diagrams. We also identify a region, in the Bayes-optimal setting, with strong hints of replica-symmetry breaking. When true parameters are unknown, we show how a maximum-likelihood procedure is able to recover them with mostly unaffected performance.
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