215 research outputs found
Gas phase selective hydrogenation of furfural to furfuryl alcohol and 2-methylfuran over Cu-CeO2 coprecipitated catalysts
Furfural is an important chemical derived from lignocellulosic biomass, in particular from C5 sugars like xylose, and it is considered as a platform molecule of great potential for the synthesis of a broad spectrum of chemicals. In this sense, furfuryl alcohol and 2-methylfuran are two important chemicals which can be produced through furfural hydrogenation, either in liquid or vapor phase, although the latter is preferred because it can be carried out at atmospheric pressure. Industrially, a copper chromite catalyst is used, although this catalyst can become very toxic due to the presence of chromium. Therefore, much attention is being paid to the development of chromium-free catalysts, more sustainable and environmentally friendly, as those based on Cu or Ni which are active and selective towards the formation of furfuryl alcohol and 2-methylfuran. Furfuryl alcohol is mainly used for the production of thermostatic resins, intermediate in the manufacture of lysine, vitamin C and dispersing agents. Meanwhile, 2-methyl furan is used in the synthesis of pesticides, or in the pharmaceutical and fragrance industries.
The aim of this work is the synthesis of a series of copper based catalysts, which have been synthesized by coprecipitation of copper and cerium(IV) and subsequent thermal programmed reduction. This method allows increasing the dispersion of Cu particles, while the use of a support like CeO2 can modify the electronic density of the active phase, which can influence the catalytic activity and resistance to deactivation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Economy and Competitiveness Ministry (Project CTQ2012-38204-C03-02), Junta de Andalucía (Project: RNM-1565) and FEDER funds of the European Unio
Trivianometrics, una competición académica por equipos en el aula de Econometría Financiera.
Memoria en formato artículo de los resultados del proyecto de innovación docente PI_14_011 realizado en la Universidad de Cádiz durante el curso 2013/14. El proyecto recibió el tercer premio de innovación docente y diploma de excelencia otorgado por la Unidad de Innovación Docente de la UCA y el Consejo Social de la Universidad de Cádiz. http://www.uca.es/recursos/doc/Unidades/Unidad_Innovacion/Innovacion_Docente/2013_2014/1266175410_285201512844.pdfMotivar a los alumnos para estudiar con regularidad y participar en clase es una tarea compleja pero fundamental en asignaturas de aprendizaje continuo, donde los nuevos conocimientos se fundamentan en conocimientos previos adquiridos en las mismas. Con el objeto de incrementar el interés y estudio de la asignatura, propusimos a los alumnos participar en una competición académica por equipos donde se pone a prueba sus conocimientos de Econometría Financiera. El diseño de Trivianometrics combina dos elementos fundamentales en el aprendizaje: 1) trabajo continuo durante el curso y 2) un incentivo a corto plazo que motive a superar las dificultades de la materia de estudio.
La competición se llevó a cabo durante el curso 2013/14 donde se creó una clasificación de equipos a partir de los puntos obtenidos en mini rondas de preguntas. Semanalmente, los alumnos tenían la posibilidad de ganar puntos para su equipo y mejorar la clasificación que se actualizaba al final de cada ronda. La distribución de los puntos se planificó de modo que se mantuviera el interés hasta el final. Tras desarrollarse la competición, se nombraron tres equipos ganadores que fueron recompensados con una nota extra en el examen y el reconocimiento público en clase con la entrega de un diploma de recuerdo.
Al final del curso, los alumnos rellenaron un encuesta de opinión sobre la utilidad y los efectos del Trivianometrics en su motivación, proceso de aprendizaje y nota final de la asignatura con resultados muy satisfactorios. Más del 70% de los alumnos encuestados consideró que la actividad había tenido efectos positivos en su estudio regular. Además, nos sorprendió gratamente que más de la mitad de los alumnos consideró más motivador el reconocimiento hacia los ganadores que los puntos extra en el examen.Unidad de Innovación Docente UCA, Universidad de Cádi
El uso de códigos QR para mejorar en Econometría. Una experiencia docente.
Memoria final en formato artículo del proyecto de innovación docente PI_13_016. El proyecto fue llevado a cabo durante el curso académico 2012/13 y recibió un accésit y diploma con mención de excelencia por la Unidad de Innovación Docente y el Consejo Social de la Universidad de Cádiz. http://www.uca.es/recursos/doc/Unidades/Unidad_Innovacion/Innovacion_Docente/2012_2013/891466831_195201411523.pdfLos teléfonos móviles, máximos representantes de la integración tecnológica en nuestra sociedad, siguen ampliando su oferta de aplicaciones para facilitar nuestra vida diaria. Sin embargo, el mundo formativo continúa sin dar el paso definitivo a estos nuevos dispositivos. Con el trasfondo de que nuestros estudiantes empiecen a utilizar sus móviles en actividades formativas (m-learning) y con el objetivo de facilitar el aprendizaje de la asignatura de Econometría, se desarrolló una serie de actividades disponibles en el móvil mediante la lectura de códigos QR que permiten a los alumnos afianzar conceptos sobre la materia de estudio. Al finalizar el curso se realizó una encuesta de opinión cuyos resultados se analizaron para detectar los factores que influyen en el uso del móvil en las actividades que se pusieron a disposición de los estudiantes. Los principales resultados muestran la importancia de tener un conocimiento previo en la lectura de códigos QR para que los alumnos consideren esta actividad una ventaja en lugar de un inconveniente. Asimismo, se detectó que ventajas del móvil como la inmediatez de uso y la portabilidad pueden quedar menoscabadas por la lentitud de las conexiones de datos y el reducido tamaño de las pantallas de estos dispositivos.Unidad de Innovación Docente UCA, Universidad de CádizEl archivo contiene la memoria en formato artículo: 4 página
CDs and N-CDs preparation from xylose and xylose-enriched biomass liquors for methyl orange photocatalytic degradation.
CDs are newly discovered carbon nanoparticles that present unique properties. Each nanoparticle consists of a graphitic lattice core covered by a functionalized surface composed by several polar functional groups attached1,2. Due to this functionalization, CDs exhibit photoinduced electronic transference, fluorescence and up-conversion photoluminescence3. CDs have raised increasing attention for their undemanding synthesis procedure combined with the fact that they have been proved to be non-toxic and can be modified to reach satisfactory quantum yield values. A current tendency in the obtention of CDs is the pursuit of a synthesis method that fulfils the requirements of green chemistry but keeps production costs low. Therefore, CDs obtained from green precursors coming from biomass is an emergent research topic4,3,5,6,7. The most frequent and best-known method for CDs production is hydrothermal or solvothermal method7,3,2.The acidic conditions required by this method are commonly achieved using mineral acids such as HCl; nonetheless, the hydrothermal method is compatible with heterogeneous catalysis, which have been proved in this work. As a consequence of their photoluminescence and electron transfer properties, CDs can work as electron mediators, photosensitizers, as well as photocatalysts by themselves 10. It has been proved that CDs when photo excited are outstandingly good electron donors and electron acceptors, since either electron acceptors or electron donors are able to quench the photoluminescence emitted by CDs effectively 9.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Si-Al nanospheres for the valorization of galactose and agarose into 5-hydroxymethylfurfural.
5-hydroxymethylfurfural (HMF) is a compound that has gained attention to potentially substitute fossil resources in areas such as the polymer industry or the production of energy vectors. HMF is produced from the acid treatment of hexoses, such as glucose or galactose. In this sense, algae biomass has gained interest as it can be grown in both, sweet and salt water and their growth rate and CO2 fixation are several times higher than those of terrestrial plants. Red algae, which are rich in agarose, a galactose and 1,6-dehydrogalactose heteropolymer, can potentially be used as feedstock to produce HMF [1].
Hence, in this work, alumina supported nanospheres have been synthetised and employed as acid catalysts due to their high acidity and porosity that allows the selective conversion of these biomass derived compounds into valuable HMF.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Early Stepdown From Echinocandin to Fluconazole Treatment in Candidemia: A Post Hoc Analysis of Three Cohort Studies
Antifúngic; Candidèmia; DesescaladaAntifúngico; Candidemia; DesescaladaAntifungal; Candidemia; De-escalationBackground
There are no clear criteria for antifungal de-escalation after initial empirical treatments. We hypothesized that early de-escalation (ED) (within 5 days) to fluconazole is safe in fluconazole-susceptible candidemia with controlled source of infection.
Methods
This is a multicenter post hoc study that included consecutive patients from 3 prospective candidemia cohorts (2007–2016). The impact of ED and factors associated with mortality were assessed.
Results
Of 1023 candidemia episodes, 235 met inclusion criteria. Of these, 54 (23%) were classified as the ED group and 181 (77%) were classified as the non-ED group. ED was more common in catheter-related candidemia (51.9% vs 31.5%; P = .006) and episodes caused by Candida parapsilosis, yet it was less frequent in patients in the intensive care unit (24.1% vs 39.2%; P = .043), infections caused by Nakaseomyces glabrata (0% vs 9.9%; P = .016), and candidemia from an unknown source (24.1% vs 47%; P = .003). In the ED and non-ED groups, 30-day mortality was 11.1% and 29.8% (P = .006), respectively. Chronic obstructive pulmonary disease (odds ratio [OR], 3.97; 95% confidence interval [CI], 1.48–10.61), Pitt score > 2 (OR, 4.39; 95% CI, 1.94–9.20), unknown source of candidemia (OR, 2.59; 95% CI, 1.14–5.86), candidemia caused by Candida albicans (OR, 3.92; 95% CI, 1.48–10.61), and prior surgery (OR, 0.29; 95% CI, 0.08–0.97) were independent predictors of mortality. Similar results were found when a propensity score for receiving ED was incorporated into the model. ED had no significant impact on mortality (OR, 0.50; 95% CI, 0.16–1.53).
Conclusions
Early de-escalation is a safe strategy in patients with candidemia caused by fluconazole-susceptible strains with controlled source of bloodstream infection and hemodynamic stability. These results are important to apply antifungal stewardship strategies.This research forms part of an activity that has received funding from EIT Health. EIT Health is supported by the European Institute of Innovation and Technology (EIT), a body of the European Union that receives support from the European Union´s Horizon 2020 Research and Innovation Program. This study has been cofunded by the European Regional Development Fund. E. M.-G. (PI18/01061), P. P.-A. (“Rio Hortega” contract CM18/00132), M. F.-R. (“Miguel Servet” contract CP18/00073), and C. G.-V. (FIS PI18/01061) have received research grants from the Ministerio de Sanidad y Consumo, Instituto de Salud Carlos III
Recent Advances in Mechanochemical Pretreatment of Lignocellulosic Biomass
Biorefineries are industrial facilities where biomass is converted into chemicals, fuels and energy. The use of lignocellulose as raw material implies the development of pretreatments to reduce its recalcitrant character prior to the processes that lead to the synthesis of the products of interest. These treatments are based on physico-chemical processes where it is necessary to use acids, bases, oxidants, and high pressure and temperature conditions that lead to the depolymerization of lignocellulose at the expense of generating a series of streams that must be treated later or to the production of by-products. In recent years, mechanochemistry is becoming relevant in the design of processes that help in the depolymerization of lignocellulose. These mechanochemical processes are being used in combination with chemicals and/or enzymes, allowing the use of minor loads of reagents or enzymes. In this review, the advances achieved in the use of mechanochemistry for treating lignocellulosic biomass or cellulose will be presented, with special emphasis on how these mechanochemical processes modify the structure of lignocellulose and help subsequent treatments. It will focus on using ball milling or extrusion, ending with a section dedicated to future work needed to implement these technologies at the industrial level.This research was funded by the Spanish Ministry of Science and Innovation (PID2021-122736OB-C42), FEDER (European Union) funds (PID2021-122736OB-C42, P20-00375, UMA20-FEDERJA88) and B.T.O. acknowledges Ministerio de Universidades for his predoctoral contract. Partial funding for open access charge: Universidad de Málag
Evaluation of Plant Protein Hydrolysates as Natural Antioxidants in Fish Oil-In-Water Emulsions
In this work, we evaluated the physical and oxidative stabilities of 5% w/w fish oil-in-water emulsions stabilized with 1%wt Tween20 and containing 2 mg/mL of protein hydrolysates from olive seed (OSM-H), sunflower (SFSM-H), rapeseed (RSM-H) and lupin (LUM-H) meals. To this end, the plant-based substrates were hydrolyzed at a 20% degree of hydrolysis (DH) employing a mixture 1:1 of subtilisin: trypsin. The hydrolysates were characterized in terms of molecular weight profile and in vitro antioxidant activities (i.e., DPPH scavenging and ferrous ion chelation). After incorporation of the plant protein hydrolysates as water-soluble antioxidants in the emulsions, a 14-day storage study was conducted to evaluate both the physical (i.e., zeta-potential, droplet size and emulsion stability index) and oxidative (e.g., peroxide and anisidine value) stabilities. The highest in vitro DPPH scavenging and iron (II)-chelating activities were exhibited by SFSM-H (IC50 = 0.05 +/- 0.01 mg/mL) and RSM-H (IC50 = 0.41 +/- 0.06 mg/mL). All the emulsions were physically stable within the storage period, with zeta-potential values below -35 mV and an average mean diameter D[4,3] of 0.411 +/- 0.010 mu m. Although LUM-H did not prevent lipid oxidation in emulsions, OSM-H and SFSM-H exhibited a remarkable ability to retard the formation of primary and secondary lipid oxidation products during storage when compared with the control emulsion without antioxidants. Overall, our findings show that plant-based enzymatic hydrolysates are an interesting alternative to be employed as natural antioxidants to retard lipid oxidation in food emulsions.Regional Ministry of Economic Transformation, Industry, Knowledge, and Universities of Andalusia (Spain) PY20_00021Colombian Ministry of Science, Technology and Innovatio
Cardiovascular disease in immune-mediated inflammatory diseases: a cross-sectional analysis of 6 cohorts
Observational study[Abstract] To analyze in several immune-mediated inflammatory diseases (IMIDs) the influence of demographic and clinical-related variables on the prevalence of cardiovascular disease (CVD), and compare their standardized prevalences.Cross-sectional study, including consecutive patients diagnosed with rheumatoid arthritis, psoriatic arthritis, psoriasis, systemic lupus erythematosus, Crohn disease, or ulcerative colitis, from rheumatology, gastroenterology, and dermatology tertiary care outpatient clinics located throughout Spain, between 2007 and 2010. Our main outcome was defined as previous diagnosis of angina, myocardial infarction, peripheral vascular disease, and/or stroke. Bivariate and multivariate logistic and mixed-effects logistic regression models were performed for each condition and the overall cohort, respectively. Standardized prevalences (in subjects per 100 patients, with 95% confidence intervals) were calculated using marginal analysis.We included 9951 patients. For each IMID, traditional cardiovascular risk factors had a different contribution to CVD. Overall, older age, longer disease duration, presence of traditional cardiovascular risk factors, and male sex were independently associated with a higher CVD prevalence. After adjusting for demographic and traditional cardiovascular risk factors, systemic lupus erythematosus exhibited the highest CVD standardized prevalence, followed by rheumatoid arthritis, psoriasis, Crohn disease, psoriatic arthritis, and ulcerative colitis (4.5 [95% confidence interval (CI): 2.2, 6.8], 1.3 [95% CI: 0.8, 1.8], 0.9 [95% CI: 0.5, 1.2], 0.8 [95% CI: 0.2, 1.3], 0.6 [95% CI: 0.2, 1.0], and 0.5 [95% CI: 0.1, 0.8], respectively).Systemic lupus erythematosus, rheumatoid arthritis, and psoriasis are associated with higher prevalence of CVD compared with other IMIDs. Specific prevention programs should be established in subjects affected with these conditions to prevent CVD
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