198 research outputs found
Iron oxide ores as carriers for the production of high purity hydrogen from biogas by steam–iron process
Production of high purity hydrogen (<50 ppm CO) by steam–iron process (SIP) from a synthetic sweetened biogas has been investigated making use of a natural iron ore containing up to 81 wt% of hematite (Fe2O3) as oxygen carrier. The presence of a lab-made catalyst (NiAl2O4 with NiO excess above its stoichiometric composition) was required to carry out the significant transformation of mixtures of methane and carbon dioxide in hydrogen and carbon monoxide by methane dry reforming reaction. Three consecutive sub-stages have been identified along the reduction stage that comprise A) the combustion of CH4 by lattice oxygen of NiO and Fe2O3, B) catalyzed methane dry reforming and C) G–G equilibrium described by the Water-Gas-Shift reaction. Oxidation stages were carried out with steam completing the cycle. Oxidation temperature was always kept constant at 500 °C regardless of the temperature used in the previous reduction to minimize the gasification of eventual carbon deposits formed along the previous reduction stage. The presence of other oxides different from hematite in minor proportions (SiO2, Al2O3, CaO and MgO to name the most significant) confers it an increased thermal resistance against sintering respecting pure hematite at the expense of slowing down the reduction and oxidation rates. A “tailor made” hematite with additives (Al2O3 and CeO2) in minor proportions (2 wt%) has been used to stablish comparisons in performance between natural and synthetic iron oxides. It has been investigated the effect of the reduction temperature, the proportion of methane to carbon dioxide in the feed (CH4:CO2 ratio) and the number of repetitive redox cycles
Engineering and Applications of fungal laccases for organic synthesis
Laccases are multi-copper containing oxidases (EC 1.10.3.2), widely distributed in fungi, higher plants and bacteria. Laccase catalyses the oxidation of phenols, polyphenols and anilines by one-electron abstraction, with the concomitant reduction of oxygen to water in a four-electron transfer process. In the presence of small redox mediators, laccase offers a broader repertory of oxidations including non-phenolic substrates. Hence, fungal laccases are considered as ideal green catalysts of great biotechnological impact due to their few requirements (they only require air, and they produce water as the only by-product) and their broad substrate specificity, including direct bioelectrocatalysis
Synthesis of 1‐Naphthol by a Natural Peroxygenase engineered by Directed Evolution
This is the peer reviewed version of the following article, which has been published in final form at 10.1002/cbic.201500493. This article may be used for non-commercial purposes in accordance With Wiley-VCH Terms and Conditions for self-archivingThere is an increasing interest in enzymes that catalyze the hydroxylation of naphthalene under mild conditions and with minimal requirements. To address this challenge, an extracellular fungal aromatic peroxygenase with mono(per)oxygenase activity was engineered to convert naphthalene selectively into 1-naphthol. Mutant libraries constructed by random mutagenesis and DNA recombination were screened for peroxygenase activity on naphthalene together with quenching of the undesired peroxidative activity on 1-naphthol (one-electron oxidation). The resulting double mutant (G241D-R257K) obtained from this process was characterized biochemically and computationally. The conformational changes produced by directed evolution improved the substrate's catalytic position. Powered exclusively by catalytic concentrations of H2O2, this soluble and stable biocatalyst has a total turnover number of 50 000, with high regioselectivity (97 %) and reduced peroxidative activity.We thank Paloma Santos Moriano (ICP, CSIC, Spain) for assistance with the HPLC and LC/MS analysis, and Jesper Vind (Novozymes, Denmark) and Angel T. Martinez (CIB, CSIC, Spain) for helpful discussions. This work was supported by the European Commission projects Indox-FP7-KBBE-2013-7-613549 and Cost-Action CM1303-Systems Biocatalysis, and the National Projects Dewry [BIO201343407-R], Cambios [RTC-2014-1777-3] and OXYdesign [CTQ2013-48287-R].Peer ReviewedPostprint (author's final draft
Enzymatic synthesis and characterization of different families of chitooligosaccharides and their bioactive properties
Chitooligosaccharides (COS) are homo- or hetero-oligomers of D-glucosamine (GlcN) and N-acetyl-D-glucosamine (GlcNAc) that can be obtained by chitosan or chitin hydrolysis. Their enzymatic production is preferred over other methodologies (physical, chemical, etc.) due to the mild conditions required, the fewer amounts of waste and its efficiency to control product composition. By properly selecting the enzyme (chitinase, chitosanase or nonspecific enzymes) and the substrate properties (degree of deacetylation, molecular weight, etc.), it is possible to direct the synthesis towards any of the three COS types: fully acetylated (faCOS), partially acetylated (paCOS) and fully deacetylated (fdCOS). In this article, we review the main strategies to steer the COS production towards a specific group. The chemical characterization of COS by advanced techniques, e.g., high-performance anion-exchange chromatography with pulsed amperometric detection (HPAECPAD) and MALDI-TOF mass spectrometry, is critical for structure-function studies. The scaling of processes to synthesize specific COS mixtures is difficult due to the low solubility of chitin/chitosan, the heterogeneity of the reaction mixtures, and high amounts of salts. Enzyme immobilization can help to minimize such hurdles. The main bioactive properties of COS are herein reviewed. Finally, the anti-inflammatory activity of three COS mixtures was assayed in murine macrophages after stimulation with lipopolysaccharidesThis work was supported by grants from the EU EMFF-Blue Economy-2018 (FISH4FISH-
863697 project), the Spanish Ministry of Economy and Competitiveness (Grants BIO2016-76601-
C3-1,2-R), the Spanish Ministry of Science and Innovation (Grants PID2019-105838RB-C31/C32),
Fundación Ramón Areces (XIX Call of Research Grants in Life and Material Sciences) and by an
institutional grant from Fundación Ramón Areces to the Centro de Biología Molecula
Sex Differences in Comorbidity, Therapy, and Health Services' Use of Heart Failure in Spain: Evidence from Real-World Data
Heart failure (HF) is becoming increasingly prevalent and affects both men and women. However, women have traditionally been underrepresented in HF clinical trials. In this study, we aimed to analyze sex differences in the comorbidity, therapy, and health services'' use of HF patients. We conducted a cross-sectional study in Aragón (Spain) and described the characteristics of 17, 516 patients with HF. Women were more frequent (57.4 vs. 42.6%, p < 0.001) and older (83 vs. 80 years, p < 0.001) than men, and presented a 33% lower risk of 1-year mortality (p < 0.001). Both sexes showed similar disease burdens, and 80% suffered six or more diseases. Some comorbidities were clearly sex-specific, such as arthritis, depression, and hypothyroidism in women, and arrhythmias, ischemic heart disease, and COPD in men. Men were more frequently anti-aggregated and anti-coagulated and received more angiotensin-converting-enzyme (ACE) inhibitors and beta-blockers, whereas women had more angiotensin II antagonists, antiinflammatories, antidepressants, and thyroid hormones dispensed. Men were admitted to specialists (79.0 vs. 70.6%, p < 0.001), hospital (47.0 vs. 38.1%, p < 0.001), and emergency services (57.6 vs. 52.7%, p < 0.001) more frequently than women. Our results highlight the need to conduct future studies to confirm the existence of these differences and of developing separate HF management guidelines for men and women that take into account their sex-specific comorbidity
Understanding the training and education needs of homecare workers supporting people with dementia and cancer: a systematic review of reviews
Many people with dementia, supported by family carers, prefer to live at home and may rely on homecare support services. People with dementia are also often living with multimorbidities, including cancer. The main risk factor for both cancer and dementia is age and the number of people living with dementia and cancer likely to rise. Upskilling the social care workforce to facilitate more complex care is central to national workforce strategies and challenges. Training and education development must also respond to the key requirements of a homecare workforce experiencing financial, recruitment and retention difficulties. This systematic review of reviews provides an overview of dementia and cancer training and education accessible to the homecare workforce. Findings reveal there is a diverse range of training and education available, with mixed evidence of effectiveness. Key barriers and facilitators to effective training and education are identified in order to inform future training, education and learning development for the homecare workforce supporting people with dementia and cancer
Co2 methanation in a ni-fe based catalyst fixed bed reactor enhanced by selective water adsorption with lta zeolites (sorption enhanced sabatier reaction – sesar)
A Fixed-Bed reactor improved by selective water adsorption LTA zeolites is proposed as an alternative to the conventional methanation reactors. This reactor produces methane from renewable H2 (i.e. surplus electricity) and high CO2 concentration sources, as could be municipal wastes derived biogas (30%v CO2 + 70%v CH4). As catalyst, a supported (-Al2O3) Ni-Fe (7.5:2.5 wt/wt) was chosen
Producción y purificación de hidrógeno a partir de etanol mediante el proceso “Steam-Iron” en un reactor de lecho fijo
El presente trabajo plantea la viabilidad de utilizar fracciones alcoholicas de un bio-oil, o alcohol de origen biológico (bioetanol) como materia prima para la obtención de hidrógeno de alta pureza mediante un proceso redox cíclico (“Steam Iron Process”) utilizando óxidos metálicos de alto contenido en hierro en un reactor de lecho fijo en operación discontinua
Molecular characterization and heterologous expression of a Xanthophyllomyces dendrorhous ¿-glucosidase with potential for prebiotics production
Abstract Basidiomycetous yeast Xanthophyllomyces dendrorhous expresses an α-glucosidase with strong transglycosylation activity producing prebiotic sugars such as panose and an unusual tetrasaccharides mixture including α–(1–6) bonds as major products, which makes it of biotechnological interest. Initial analysis pointed to a homodimeric protein of 60 kDa subunit as responsible for this activity. In this study, the gene Xd-AlphaGlu was characterized. The 4131-bp-long gene is interrupted by 13 short introns and encodes a protein of 990 amino acids (Xd-AlphaGlu). The N-terminal sequence of the previously detected 60 kDa protein resides in this larger protein at residues 583–602. Functionality of the gene was proved in Saccharomyces cerevisiae, which produced a protein of about 130 kDa containing Xd-AlphaGlu sequences. All properties of the heterologously expressed protein, including thermal and pH profiles, activity on different substrates, and ability to produce prebiotic sugars were similar to that of the α-glucosidase produced in X. dendrorhous. No activity was detected in S. cerevisiae containing exclusively the 1256-bp from gene Xd-AlphaGlu that would encode synthesis of the 60 kDa protein previously detected. Data were compatible with an active monomeric α-glucosidase of 990 amino acids and an inactive hydrolysis product of 60 kDa. Protein Xd-AlphaGlu contained most of the elements characteristic of α-glucosidases included in the glycoside hydrolases family GH31 and its structural model based on the homologous human maltase-lucoamylase was obtained. Remarkably, the Xd-AlphaGlu C-terminal domain presents an unusually long 115-residue insertion that could be involved in this enzyme’s activity against long-size substrates such as maltoheptaose and soluble starch.Spanish Ministry of Economy and Competitiveness supported this research. We thank Fundación Ramón Areces for the institutional grant to the Centro de Biología Molecular Severo OchoaPeer Reviewe
Chronic Obstructive Pulmonary Disease and Incidence of Hip Fracture: A Nested Case-Control Study in the EpiChron Cohort
Purpose: To determine whether chronic obstructive pulmonary disease (COPD) is a risk factor for hip fracture and identify other factors associated with hip fracture.
Patients and Methods: Observational nested case-control study was conducted in Aragon, Spain in 2010. We included COPD patients aged >40 years, in the EpiChron cohort. Each COPD patient was matched for age, sex, and number of comorbidities with a control subject without COPD. Patients with an existing diagnosis of osteoporosis and those with hip fracture before 2011 were excluded. We collected baseline demographic, comorbidity, and pharmacological treatment data. During a 5-year follow-up period, we recorded the incidence of hip fracture. A logistic regression model was constructed to identify factors associated with hip fracture.
Results: The study population consisted of 26, 517 COPD patients and the same number of controls (median [interquartile range] age, 74 [17] years; women, 24.7%). Smoking and heart failure were more frequent in COPD patients, and obesity, hypertension, diabetes, dyslipidemia, stroke, arthritis, and visual or hearing impairment were less frequent (all p<0.001). Consumption of benzodiazepines (p=0.037), bronchodilators (p<0.001), and corticosteroids (p<0.001) was higher in the COPD group, while that of beta-blockers and thiazides was lower (both p<0.001). During follow-up, 898 (1.7%) patients experienced hip fracture, with no differences observed between COPD and control patients. Multivariate analysis revealed that independent of COPD status, age, female sex, chronic liver disease, heart failure, and benzodiazepine use were independently associated with a higher risk of hip fracture, and obesity with a lower risk. In COPD patients, use of inhaled anticholinergics was independently associated with hip fracture (OR, 1.390; 95% CI 1.134-1.702; p=0.001).
Conclusion: COPD is not a risk factor for a hip fracture within 5 years. The association between the use of inhaled anticholinergics and risk of hip fracture warrants further study
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