91 research outputs found
Energy performance of Power-to-Liquid applications integrating biogas upgrading, reverse water gas shift, solid oxide electrolysis and Fischer-Tropsch technologies
Power-to-liquid (P2L) pathways represent a possible solution for the conversion of carbon dioxide into synthetic value-added products. The present work analyses different power-to-liquid options for the synthesis of Fischer-Tropsch (FT) fuels and chemicals. The FT section is integrated into a complete carbon capture and utilization route. The involved processes are a biogas upgrading unit for CO2 recovery, a reverse water gas shift, a solid oxide electrolyser and a Fischer-Tropsch reactor.The upgrading plant produces about 1 ton/h of carbon dioxide. The recovered CO2 is fed to either a reverse water gas shift reactor or a solid oxide electrolysis unit operating in co-electrolysis mode for the generation of syngas. The produced syngas is fed to a Fischer-Tropsch reactor at 501 K and 25 bar for the synthesis of the Fischer-Tropsch products, which are further separated into different classes based on their boiling point to yield light gas, naphtha, middle distillates, light waxes and heavy waxes. The developed process model uses a detailed carbide kinetic model to describe the formation of paraffins and olefins based on real experimental data. The effect of Fischer-Tropsch off-gas recirculation has been studied against a one-through option. Finally, energy integration of each configuration plant is provided. Results from process simulations show that the best model configurations reach a plant efficiency of 81.1% in the case of solid oxide electrolyser as syngas generator, and 71.8% in the case of reverse water gas shift option, with a global carbon reduction potential of 79.4% and 81.7%, respectively
MFI vs. FER zeolite during methanol dehydration to dimethyl ether: The crystal size plays a key role
Abstract FER-type zeolite was recently recognized as good catalyst for DME synthesis via methanol dehydration or one-pot CO2 hydrogenation, in terms of DME selectivity, stability and coke formation. In this research, we investigated the role of crystal size of both FER- and MFI-type zeolites on catalysis of methanol dehydration to DME reaction. The results show that FER-type zeolites, both micro- and nano-sized, exhibit better performances than micro-sized MFI-type zeolite. On the contrary, the application of nano-sized MFI allows to obtain a DME selectivity similar to FER, but with higher DME production rate and a lower coke deposition
CO2 conversion into hydrocarbons via modified Fischer-Tropsch synthesis by using bulk iron catalysts combined with zeolites
To effectively address the challenges posed by global warming, a prompt and coordinated effort is necessary to conduct an extensive study aimed at reducing CO2 emissions and overcoming the obstacles presented by expensive and scarce fossil fuel resources. This study primarily focuses on comparing two different methodologies for preparing Na-promoted Fe3O4-based catalysts for the CO2 hydrogenation into hydrocarbon mixtures. Three catalysts were synthesized and tested: two samples were impregnated with a different amount of Na (1 wt% and 5 wt%), while a third one was obtained via coprecipitation with NaOH. As the latter catalyst exhibited the best performance, it was combined with zeolites in two ways: physical mixtures and core-shell structures. MFI-type zeolites were used in both configurations and a conventional structure was compared to a hierarchical one. As a result, mesopores increased successfully both the CO2 conversion from 37% to 40% and the liquid hydrocarbon (C6+) selectivity from 29% to 57%, doubling the C6+ yield. On the other hand, NH3-TPD and XPS measurements demonstrated that the intimate contact between the two materials in the core-shell structures led to the migration of Na from the oxide to the zeolite reducing the concentration of strong acid sites and, consequently, the liquid hydrocarbon yield
The added value of spinal cord lesions to disability accrual in multiple sclerosis
Spinal cord MRI is not routinely performed for multiple sclerosis (MS) monitoring. Here, we explored whether spinal cord MRI activity offers any added value over brain MRI activity for clinical outcomes prediction in MS. This is a retrospective, monocentric study including 830 MS patients who underwent longitudinal brain and spinal cord MRI [median follow-up 7 years (range: < 1–26)]. According to the presence (or absence) of MRI activity defined as at least one new T2 lesion and/or gadolinium (Gd) enhancing lesion, each scan was classified as: (i) brain MRI negative/spinal cord MRI negative; (ii) brain MRI positive/spinal cord MRI negative; (iii) brain MRI negative/spinal cord MRI positive; (iv) brain MRI positive/spinal cord MRI positive. The relationship between such patterns and clinical outcomes was explored by multivariable regression models. When compared with the presence of brain MRI activity alone: (i) Gd + lesions in the spine alone and both in the brain and in the spinal cord were associated with an increased risk of concomitant relapses (OR = 4.1, 95% CI 2.4–7.1, p < 0.001 and OR = 4.9, 95% CI 4.6–9.1, p < 0.001, respectively); (ii) new T2 lesions at both locations were associated with an increased risk of disability worsening (HR = 1.4, 95% CI = 1.0–2.1, p = 0.05). Beyond the presence of brain MRI activity, new spinal cord lesions are associated with increased risk of both relapses and disability worsening. In addition, 16.1% of patients presented asymptomatic, isolated spinal cord activity (Gd + lesions). Monitoring MS with spinal cord MRI may allow a more accurate risk stratification and treatment optimization
Splicing Factors Induce Cystic Fibrosis Transmembrane Regulator Exon 9 Skipping through a Nonevolutionary Conserved Intronic Element
In monosymptomatic forms of cystic fibrosis such as congenital bilateral absence of vas deferens, variations in the TG(m) and T(n) polymorphic repeats at the 3' end of intron 8 of the cystic fibrosis transmembrane regulator (CFTR) gene are associated with the alternative splicing of exon 9, which results in a nonfunctional CFTR protein. Using a minigene model system, we have previously shown a direct relationship between the TG(m)T(n) polymorphism and exon 9 splicing. We have now evaluated the role of splicing factors in the regulation of the alternative splicing of this exon. Serine-arginine-rich proteins and the heterogeneous nuclear ribonucleoprotein A1 induced exon skipping in the human gene but not in its mouse counterpart. The effect of these proteins on exon 9 exclusion was strictly dependent on the composition of the TG(m) and T(n) polymorphic repeats. The comparative and functional analysis of the human and mouse CFTR genes showed that a region of about 150 nucleotides, present only in the human intron 9, mediates the exon 9 splicing inhibition in association with exonic regulatory elements. This region, defined as the CFTR exon 9 intronic splicing silencer, is a target for serine-arginine-rich protein interactions. Thus, the nonevolutionary conserved CFTR exon 9 alternative splicing is modulated by the TG(m) and T(n) polymorphism at the 3' splice region, enhancer and silencer exonic elements, and the intronic splicing silencer in the proximal 5' intronic region. Tissue levels and individual variability of splicing factors would determine the penetrance of the TG(m)T(n) locus in monosymptomatic forms of cystic fibrosis
The Brief Strategic Treatment of Cardiophobia: A Clinical Case Study
AbstractMany individuals presenting to medical settings with heart-related symptoms for which no medical explanation is found might suffer from cardiophobia, but this condition is still poorly identified and addressed. This article presents a case of cardiophobia treated in an outpatient cardiac rehabilitation unit and, for the first time, describes the application of brief strategic therapy for the treatment of this condition. In the case reported, the first therapeutic encounter and the key elements of the strategic approach are described in detail with the aim to explain how brief strategic therapy works and how it can be used to identify and address cardiophobia-related behaviors. A 64-year-old male presented to cardiac rehabilitation reporting intense anxiety-provoking heart palpitations, and believing he was at risk of dying from a heart attack. After 3 sessions, an overall improvement in heart-related bodily sensations followed a decrease in the patient's continuous checking of his heartbeat and seeking reassurance—factors that were largely responsible for the persistence of the problem. Moreover, quantitative evaluation showed increased scores of mood state at the end of treatment. This improvement persisted at the 18-month follow-up. This case is an interesting example of how brief strategic therapy can contribute to the development of a new conceptual model for the diagnosis and treatment of cardiophobia. Still, more systematic research in the field is needed to prove the efficacy and effectiveness of this therapeutic approach on symptoms of heart-focused anxiety
Estudio clínico y molecular en una familia con displasia ectodérmica hipohidrótica autosómica dominante
Hypohidrotic ectodermal dysplasia (HED) is a rare disease characterized by deficiency in development of structure derived from the ectoderm and is caused by mutations in the genes EDA, EDAR, or EDARADD. Phenotypes caused by mutations in these three may exhibit similar clinical features, explained by a common signaling pathway. Mutations in EDA gene cause X linked HED, which is the most common form. Mutations in EDAR and EDARADD genes cause autosomal dominant and recessive form of HED. The most striking clinical findings in HED are hypodontia, hypotrichosis and hypohidrosis that can lead to episodes of hyperthermia. We report on clinical findings in a child with HED with autosomal dominant inheritance pattern with a heterozygous mutation c.1072C>T (p.Arg358X) in the EDAR gene. A review of the literature with regard to other cases presenting the same mutation has been carried out and discussed
Impact of liver cirrhosis, severity of cirrhosis and portal hypertension on the difficulty of laparoscopic and robotic minor liver resections for primary liver malignancies in the anterolateral segments
Underlying Event measurements in pp collisions at and 7 TeV with the ALICE experiment at the LHC
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