Harnessing an adapted strain of Clostridium carboxidivorans to unlock hexanol production from carbon dioxide and hydrogen in elevated-pressure stirred tank reactors

To successfully scale-up the production of bio-based building blocks through CO2 and H2-based gas fermentation, it is crucial to deeply understand and control the microbial catalyst response to the bioreactor environment. This study investigates the effects of key process parameters, such as CO2 and H2 partial pressures, gas feeding strategies, and mixture composition, on the production pathways of an evolved Clostridium carboxidivorans strain. The ultimate goal is to optimize 1-hexanol production in elevated-pressure stirred-tank reactors. Continuous gas feeding enhanced acetogenic and solventogenic metabolisms, while gas-limited conditions promoted chain elongation to caproic acid. An optimized process, combining an initial gas-limited step followed by a continuous gas phase, increased 1-hexanol production, achieving a maximum biomass-specific productivity of 0.9 g gCDW−1 day−1. In-situ product extraction improved 1-hexanol carbon selectivity to an unprecedented 60 %. These findings demonstrate the potential of CO2 and H2-fed fermentation to produce high-value chemicals other than ethanol and acetate

Computing the capacity of discrete channels using vector flows

One of the fundamental problems of information theory, since its foundation by Shannon in 1948, has been the computation of the capacity of a discrete memoryless channel, a quantity expressing the maximum rate at which information can travel through the channel. In the literature, several algorithms were proposed to estimate the channel capacity, as an analytical solution is unavailable for the general channel. We propose a novel approach based on a continuous-time dynamical system to compute the capacity. We then derive an algorithm for computing the capacity, obtained by discretizing the flow that rules the evolution of this dynamical system. In the experimental analysis, we test the performance of our algorithm when different numerical ordinary differential equation solvers are utilized for its implementation. Remarkably, the results show that the algorithm is effective in computing the capacity

Methodologies for Modeling, Assessment, and Optimization of Integrated Community Energy Systems

L'abstract è presente nell'allegato / the abstract is in the attachmen

LA PUBBLICITÀ È L’ANIMA DEL COMMERCIO

Ever since the pioneering work of Vance Packard, the relationship between the advertising system and urban spaces has been the subject of observations and orientations that have been the direct legacy of, on the one hand, the use of billboards between the 19th and 20th centuries, on the other hand, consumption studies, and, finally, the relationship with the modernization of cities, based on inurbative processes, changes in circulation, and citizen-customer sensibilitie

Compressed sensing for inverse problems and the sample complexity of the sparse Radon transform

Compressed sensing allows for the recovery of sparse signals from few measurements, whose number is proportional to the sparsity of the unknown signal, up to logarithmic factors. The classical theory typically considers either random linear measurements or subsampled isometries and has found many applications, including accelerated magnetic resonance imaging, which is modeled by the subsampled Fourier transform. In this work, we develop a general theory of infinite-dimensional compressed sensing for abstract inverse problems, possibly ill-posed, involving an arbitrary forward operator. This is achieved by considering a generalized restricted isometry property and a quasi-diagonalization property of the forward map. As a notable application, for the first time, we obtain rigorous recovery estimates for the sparse Radon transform (i.e., with a finite number of angles 1; : : : ; m), which models computed tomography, in both the parallel-beam and the fan-beam settings. In the case when the unknown signal is s-sparse with respect to an orthonormal basis of compactly supported wavelets, we prove stable recovery under the condition m & s, up to logarithmic factors

External Business Drivers of Concession Period in Transport PPPs: An Empircal Investigation

Despite the abundance of papers on establishing the optimal concession period for Public Private Partnerships (PPP) from the public procurement perspective, the impact of external factors influencing the duration of the concession period of PPP projects is scarcely explored in the PPP literature. In this context, this research conducts a statistical analysis using multivariate regression analysis (MRA) and analysis of variance (ANOVA) to evaluate if a set of key factors may influence the duration of the concession period of a PPP transportation project. The outcomes of the model show that the area of the world wherein the project is developed and the regulatory framework of the country significantly impact the definition of the concession period. The proposed study paves the way for understanding the crucial levers influencing the duration of the concession period to increase the value associated with a PPP initiative

Impact of concomitant aortic valve replacement in patients with mild-to-moderate aortic valve regurgitation undergoing left ventricular assist device implantation: EUROMACS analysis

Introduction: Left ventricular assist device (LVAD) therapy may lead to an aortic regurgitation, limiting left ventricular unloading and causing adverse events. Whether concomitant aortic valve replacement may improve outcomes in patients with preoperative mild-to-moderate aortic regurgitation remains unclear. Methods: A retrospective propensity score-matched analysis of adult patients with preoperative mild-to-moderate aortic regurgitation undergoing durable LVAD implantation between 01/01/2011 and 30/11/2021 was performed. Patients undergoing concomitant valve surgery other than biological aortic valve replacement were excluded, resulting in 77 with concomitant biological aortic valve replacement and 385 without. Results: Following 1:1 propensity score matching, two groups of 55 patients with and without biological aortic valve replacement were obtained, (mean age 59 ± 11 years, 92% male, 59.1% HeartWare). Aortic regurgitation was mild in 72.7% and 76.4% and moderate in 27.3% and 23.6% in non-replacement and replacement cohorts respectively. The 30-day survival was 89.1% vs. 85.5% (p = 0.59), 1-year survival 69.1% vs. 56.4% (p = 0.19), and 2-year survival 61.8% vs. 47.3% (p = 0.10) in the non-replacement and replacement groups, respectively. After a mean follow-up of 1.2 years, non-replacement patients had a higher incidence of pump thrombosis (11 [20%] vs. 3 [5.5%], p = 0.022) and fewer major bleedings (2 [3.6%] vs. 11 [20%], p = 0.008). Conclusion: Compared with those treated conservatively, patients with mild-to-moderate aortic regurgitation undergoing concomitant aortic valve replacement during LVAD implantation have a similar survival up to 2 years on support. Patients with concomitant valve replacement had a higher risk of bleeding complications but fewer pump thromboses