43 research outputs found

    Catalytic upgrading of clean biogas to synthesis gas

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    Clean biogas, produced by anaerobic digestion of biomasses or organic wastes, is one of the most promising substitutes for natural gas. After its purification, it can be valorized through different reforming processes that convert CH4 and CO2 into synthesis gas (a mixture of CO and H2). However, these processes have many issues related to the harsh conditions of reaction used, the high carbon formation rate and the remarkable endothermicity of the reforming reactions. In this context, the use of the appropriate catalyst is of paramount importance to avoid deactivation, to deal with heat issues and mild reaction conditions and to attain an exploitable syngas composition. The development of a catalyst with high activity and stability can be achieved using different active phases, catalytic supports, promoters, preparation methods and catalyst configurations. In this paper, a review of the recent findings in biogas reforming is presented. The different elements that compose the catalytic system are systematically reviewed with particular attention on the new findings that allow to obtain catalysts with high activity, stability, and resistance towards carbon formation

    Investigation of the PI Control Parameters on the Low Temperature Synthesis of 2-octanone

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    Temperature control is probably the most important factor that influences a chemical reaction yield, in particular when working with strongly exothermic reactions. The oxidation of 2-octanol to 2-octanone is a well-known two phase (liquid-liquid) oxidation reaction, and it suffers of yield loss due to side reactions that lead to further oxidation to a mixture of carboxylic acids. As the reaction is exothermic, controlling the reactor temperature is extremely important for a safe operation. A temperature control naturally induces fluctuations within the system, which can impact the kinetics of the desired reaction. The aim of this work is to investigate the impact of the Proportional-Integral temperature controller parameters on the conversion to 2-octanone. The reaction is carried out in a semi-batch reactor, dosing 2-octanol on a solution of nitric acid. The production of nitrosonium ion is promoted by adding sodium nitrite to the nitric acid. The reaction is carried out with high stirring speed, in order to work under full chemical control regime, avoiding the effect of material diffusion between the two phases. Several simulations were done referring to an Easymaxℱ 402 Workstation (Mettler Toledo) under an isothermal temperature control mode. Target temperatures were chosen in the -15 - 15 °C range. The proportional parameter was tested in the range of 5-15, and the integral parameter was kept in the range of 60-600 s. Results showed that runaway boundaries are significatively affected by the values of the temperature controller parameters, highlighting how it is fundamental a calorimetric investigation of the process in view of a safe process optimization

    Evaluation of the Catalytic Activity of Metal Phosphates and Related Oxides in the Ketonization of Propionic Acid

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    In recent years, the upgrading of lignocellulose bio-oils from fast-pyrolysis by means of ketonization has emerged as a frontier research domain to produce a new generation of biofuels. Propionic acid (PA) ketonization is extensively investigated as a model reaction over metal oxides, but the activity of other materials, such as metal phosphates, is mostly unknown. Therefore, PA ketonization was preliminarily investigated in the gas phase over both phosphates and oxides of Al, Zr, and La. Their catalytic activity was correlated to the physicochemical properties of the materials characterized by means of XRD, XRF, BET N2 porosimetry, and CO2- and NH3-TPD. Noteworthy, monoclinic ZrO2 proved to be the most promising candidate for the target reaction, leading to a 3-pentanone productivity as high as 5.6 h 121 in the optimized conditions. This value is higher than most of those reported for the same reaction in both the academic and patent literature

    Efficient low-loaded ternary Pd-In2O3-Al2O3 catalysts for methanol production

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    Pd-In2O3 catalysts are among the most promising alternatives to Cu-ZnO-Al2O3 for synthesis of CH3OH from CO2. However, the intrinsic activity and stability of In2O3 per unit mass should be increased to reduce the content of this scarcely available element and to enhance the catalyst lifetime. Herein, we propose and demonstrate a strategy for obtaining highly dispersed Pd and In2O3 nanoparticles onto an Al2O3 matrix by a one-step coprecipitation followed by calcination and activation. The activity of this catalyst is comparable with that of a Pd-In2O3 catalyst (0.52 vs 0.55 gMeOH h−1 gcat-1 at 300 \ub0C, 30 bar, 40,800 mL h−1 gcat-1) but the In2O3 loading decreases from 98 to 12 wt% while improving the long-term stability by threefold at 30 bar. In the new Pd-In2O3-Al2O3 system, the intrinsic activity of In2O3 is highly increased both in terms of STY normalized to In specific surface area and In2O3 mass (4.32 vs 0.56 g gMeOH h−1 gIn2O3-1 of a Pd- In2O3 catalyst operating at 300 \ub0C, 30 bar, 40,800 mL h−1 gcat-1).The combination of ex situ and in situ catalyst characterizations during reduction provides insights into the interaction between Pd and In and with the support. The enhanced activity is likely related to the close proximity of Pd and In2O3, wherein the H2 splitting activity of Pd promotes, in combination with CO2 activation over highly dispersed In2O3 particles, facile formation of CH3OH

    Clusterization of co-morbidities and multi-morbidities among persons living with HIV: a cross-sectional study

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    Background: Among people living with HIV (PLWH), the prevalence of non-HIV related co-morbidities is increasing. Aim of the present study is to describe co-morbidity and multi-morbidity, their clustering mode and the potential disease-disease interactions in a cohort of Italian HIV patients. Methods: Cross-sectional analysis conducted by the Coordinamento Italiano per lo Studio di Allergia e Infezioni da HIV (CISAI) on adult subjects attending HIV-outpatient facilities. Non-HIV co-morbidities included: cardiovascular disease, diabetes mellitus, hypertension, oncologic diseases, osteoporosis, probable case of chronic obstructive pulmonary disease (COPD), hepatitis C virus (HCV) infection, psychiatric illness, kidney disease. Multi-morbidity was defined as the presence of two or more co-morbidities. Results: One thousand and eighty-seven patients were enrolled in the study (mean age 47.9 \ub1 10.8). One hundred-ninety patients (17.5%) had no co-morbidity, whereas 285 (26.2%) had one condition and 612 (56.3%) were multi-morbid. The most recurrent associations were: 1) dyslipidemia + hypertension (237, 21.8%); 2) dyslipidemia + COPD (188, 17.3%); 3) COPD + HCV-Ab+ (141, 12.9%). Multi-morbidity was associated with older age, higher body mass index, current and former smoking, CDC stage C and longer ART duration. Conclusions: More than 50% of PLHW were multi-morbid and about 30% had three or more concurrent comorbidities. The identification of common patterns of comorbidities address the combined risks of multiple drug and disease-disease interactions

    A High Pressure Operando Spectroscopy Examination of Bimetal Interactions in ‘Metal Efficient’ Palladium/In2O3/Al2O3 Catalysts for CO2 Hydrogenation

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    CO2 hydrogenation to methanol has the potential to serve as a sustainable route to a wide variety of hydrocarbons, fuels and plastics in the quest for net zero. Synergistic Pd/In2O3 (Palldium on Indium Oxide) catalysts show high CO2 conversion and methanol selectivity, enhancing methanol yield. The identity of the optimal active site for this reaction is unclear, either as a Pd−In alloy, proximate metals, or distinct sites. In this work, we demonstrate that metal-efficient Pd/In2O3 species dispersed on Al2O3 can match the performance of pure Pd/In2O3 systems. Further, we follow the evolution of both Pd and In sites, and surface species, under operando reaction conditions using X-ray Absorption Spectroscpy (XAS) and infrared (IR) spectroscopy. In doing so, we can determine both the nature of the active sites and the influence on the catalytic mechanism

    A high pressure operando spectroscopy examination of bimetal interactions in ‘Metal Efficient’ palladium/In 2 O 3 /Al 2 O 3 catalysts for CO 2 hydrogenation

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    CO2 hydrogenation to methanol has the potential to serve as a sustainable route to a wide variety of hydrocarbons, fuels and plastics in the quest for net zero. Synergistic Pd/In2O3 (Palldium on Indium Oxide) catalysts show high CO2 conversion and methanol selectivity, enhancing methanol yield. The identity of the optimal active site for this reaction is unclear, either as a Pd−In alloy, proximate metals, or distinct sites. In this work, we demonstrate that metal‐efficient Pd/In2O3 species dispersed on Al2O3 can match the performance of pure Pd/In2O3 systems. Further, we follow the evolution of both Pd and In sites, and surface species, under operando reaction conditions using X‐ray Absorption Spectroscpy (XAS) and infrared (IR) spectroscopy. In doing so, we can determine both the nature of the active sites and the influence on the catalytic mechanism

    Carriers of ADAMTS13 Rare Variants Are at High Risk of Life-Threatening COVID-19

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    Thrombosis of small and large vessels is reported as a key player in COVID-19 severity. However, host genetic determinants of this susceptibility are still unclear. Congenital Thrombotic Thrombocytopenic Purpura is a severe autosomal recessive disorder characterized by uncleaved ultra-large vWF and thrombotic microangiopathy, frequently triggered by infections. Carriers are reported to be asymptomatic. Exome analysis of about 3000 SARS-CoV-2 infected subjects of different severities, belonging to the GEN-COVID cohort, revealed the specific role of vWF cleaving enzyme ADAMTS13 (A disintegrin-like and metalloprotease with thrombospondin type 1 motif, 13). We report here that ultra-rare variants in a heterozygous state lead to a rare form of COVID-19 characterized by hyper-inflammation signs, which segregates in families as an autosomal dominant disorder conditioned by SARS-CoV-2 infection, sex, and age. This has clinical relevance due to the availability of drugs such as Caplacizumab, which inhibits vWF-platelet interaction, and Crizanlizumab, which, by inhibiting P-selectin binding to its ligands, prevents leukocyte recruitment and platelet aggregation at the site of vascular damage

    An explainable model of host genetic interactions linked to COVID-19 severity

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    We employed a multifaceted computational strategy to identify the genetic factors contributing to increased risk of severe COVID-19 infection from a Whole Exome Sequencing (WES) dataset of a cohort of 2000 Italian patients. We coupled a stratified k-fold screening, to rank variants more associated with severity, with the training of multiple supervised classifiers, to predict severity based on screened features. Feature importance analysis from tree-based models allowed us to identify 16 variants with the highest support which, together with age and gender covariates, were found to be most predictive of COVID-19 severity. When tested on a follow-up cohort, our ensemble of models predicted severity with high accuracy (ACC = 81.88%; AUCROC = 96%; MCC = 61.55%). Our model recapitulated a vast literature of emerging molecular mechanisms and genetic factors linked to COVID-19 response and extends previous landmark Genome-Wide Association Studies (GWAS). It revealed a network of interplaying genetic signatures converging on established immune system and inflammatory processes linked to viral infection response. It also identified additional processes cross-talking with immune pathways, such as GPCR signaling, which might offer additional opportunities for therapeutic intervention and patient stratification. Publicly available PheWAS datasets revealed that several variants were significantly associated with phenotypic traits such as "Respiratory or thoracic disease", supporting their link with COVID-19 severity outcome.A multifaceted computational strategy identifies 16 genetic variants contributing to increased risk of severe COVID-19 infection from a Whole Exome Sequencing dataset of a cohort of Italian patients

    Gain- and Loss-of-Function CFTR Alleles Are Associated with COVID-19 Clinical Outcomes

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    Carriers of single pathogenic variants of the CFTR (cystic fibrosis transmembrane conductance regulator) gene have a higher risk of severe COVID-19 and 14-day death. The machine learning post-Mendelian model pinpointed CFTR as a bidirectional modulator of COVID-19 outcomes. Here, we demonstrate that the rare complex allele [G576V;R668C] is associated with a milder disease via a gain-of-function mechanism. Conversely, CFTR ultra-rare alleles with reduced function are associated with disease severity either alone (dominant disorder) or with another hypomorphic allele in the second chromosome (recessive disorder) with a global residual CFTR activity between 50 to 91%. Furthermore, we characterized novel CFTR complex alleles, including [A238V;F508del], [R74W;D1270N;V201M], [I1027T;F508del], [I506V;D1168G], and simple alleles, including R347C, F1052V, Y625N, I328V, K68E, A309D, A252T, G542*, V562I, R1066H, I506V, I807M, which lead to a reduced CFTR function and thus, to more severe COVID-19. In conclusion, CFTR genetic analysis is an important tool in identifying patients at risk of severe COVID-19
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