Estado del arte de la generación de vapor mediante combustión en lecho fluido

El objetivo de este proyecto es el de hacer una revisión acerca del estado del arte de la tecnología de lecho fluido. Se comienza la revisión considerando los inicios y el desarrollo de estas tecnologías, así como las perspectivas de mejora y los elementos críticos que habría que optimizar. También se explican los fundamentos termodinámicos de la tecnología de lecho fluido, resaltando el control de emisiones y el amplio intervalo de combustibles utilizables. Asimismo se clasifican estas tecnologías en base a las distintas propiedades que las caracterizan, como son la velocidad del fluido a su paso por el lecho, el tipo de alimentación que tiene el lecho o la presión a la que opera la planta. La última sección de este proyecto muestra plantas comerciales, actualmente en funcionamiento, que utilizan distintas variedades de estas tecnologíasIn this paper we point out the state of the art of the technologies of fluidized bed combustion. The revision starts considering the beginnings and development of these technologies, in addition of the perspectives of improvement and the critical elements. There is also an explanation of the thermodynamic bases of this technology, evidencing the control of emissions and the wide range of fuels which can be burned in them. You will also be able to find a classification of these technologies based on the different properties which describe them like, the velocity of the flux through the bed, the way the fuel can be fed in the bed and the pressure at which the plant operates. The final section of this paper shows some commercial plants, using the different varieties of fluidized beds, which are operating nowadays.Universidad de Sevilla. Grado en Ingeniería de Tecnologías Industriale

Study of the reaction 2-(p-nitrophenyl)ethyl bromide + OH- in dimeric micellar solutions

The dehydrobromination reaction 2-(p-nitrophenyl)ethyl bromide + OH− was investigated in several alkanediyl---bis(dodecyldimethylammonium) bromide, 12-s- 12,2Br− (with s = 2, 3, 4, 5, 6, 8, 10, 12) micellar solutions, in the presence of NaOH 5 × 10−3 M. The kinetic data were quantitatively rationalized within the whole surfactant concentration range by using an equation based on the pseudophase ion-exchange model and taking the variations in the micellar ionization degree caused by the morphological transitions into account. The agreement between the theoretical and the experimental data was good in all the dimeric micellar media studied, except for the 12-2-12,2Br− micellar solutions. In this case, the strong tendency to micellar growth shown by the 12-2-12,2Br− micelles could be responsible for the lack of accordance. Results showed that the dimeric micelles accelerate the reaction more than two orders of magnitude as compared to waterConsejería de Innovación, Ciencia y Empresa de la Junta de Andalucía FQM-274and P07-FQM-03056DGCYT grant BQU2009-0747

Synergism Effect between Phenolic Metabolites and Endogenous Antioxidants in Terms of Antioxidant Activity

Polyphenolic compounds, widely distributed in plant kingdom, have been exhaustively studied for their bioactive properties specially antioxidant activity. However, they are extensively metabolized by human organism and the resulting metabolites are largely responsible for their effects. Furthermore, they may interact with the endogenous antioxidant network being this possibility scarcely studied. Plasma antioxidant network encompasses antioxidant enzymes and other substances such as uric acid. In addition, ascorbic acid is the major compound representing water soluble compartment both in foods and human body. The interaction of this vitamin with phenolic compound is largely unexplored. This work aims to study if there is a synergic effect between phenolic metabolites and main antioxidants (uric and ascorbic acid). For this purpose, the antioxidant activity was evaluated in terms of ORAC (oxygen radical absorbance capac ity) and FRAP (ferricreducing antioxidant power) as these tests involved either HAT (Hydrogen Atom Transfer) or SET (Single Electron Transfer) mechanisms. Additionally, a kinetic studied was developed to test if the rate constant presented a synergic effect. Protocatechuic acid, 3, 4 -dihydroxyphenylacetic acid, 3,4 -dihydroxyphenylpropionic acid and 3 -hydroxyphenylacetic acid were selected as they were metabolites of polyphenol compounds such as anthocyanins, quercetin, neohesperidin, chlorogenic acid and hesperetin present in wines, orange and strawberries. A synergic effect was proved for the combination of ascorbic acid with 3,4 -dihydroxyphenylacetic acid, both in terms of antioxidant activity and potent increase of velocity of the antioxidant reaction that took place.Ministerio de Economía y Competitividad AGL-2010-22152-C03-0

Preparation and Characterization of New Liposomes. Bactericidal Activity of Cefepime Encapsulated into Cationic Liposomes

Cefepime is an antibiotic with a broad spectrum of antimicrobial activity. However, this antibiotic has several side effects and a high degradation rate. For this reason, the preparation and characterization of new liposomes that are able to encapsulate this antibiotic seem to be an important research line in the pharmaceutical industry. Anionic and cationic liposomes were prepared and characterized. All cationic structures contained the same cationic surfactant, N,N,N-triethyl-N-(12-naphthoxydodecyl)ammonium. Results showed a better encapsulation-efficiency percentage (EE%) of cefepime in liposomes with phosphatidylcholine and cholesterol than with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). The presence of cholesterol and the quantity of egg-yolk phospholipid in the liposome increased the encapsulation percentage. The bactericidal activity against Escherichia coli of cefepime loaded into liposomes with phosphatidylcholine was measured. The inhibitory zone in an agar plate for free cefepime was similar to that obtained for loaded cefepime. The growth-rate constant of E. coli culture was also measured in working conditions. The liposome without any antibiotic exerted no influence in such a rate constant. All obtained results suggest that PC:CH:12NBr liposomes are biocompatible nanocarriers of cefepime that can be used in bacterial infections against Escherichia coli with high inhibitory activity

Binding of DNA by a dinitro-diester calix[4]arene: Denaturation and condensation of DNA

A study of a dinitro-diester calix[4]arene (5,17-(3-nitrobenzylideneamino)-11,23-di-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene) interaction with calf-thymus DNA was carried out using several techniques. The measurements were done at various molar ratios X=[calixarene]/[DNA]. Results show diverse changes in the DNA conformation depending on the X value. Thus, at low macrocycle concentrations, the calixarene binds to the polynucleotide. This interaction, mainly in groove mode, weakens the hydrogen bonds between base pairs of the helix inducing denaturation of the double strands, as well as condensation of the macromolecule, from an extended coil state to a globular state. An opposite effect is observed at X molar ratios higher than 0.07. The de-condensation of DNA happens, that is, the transition from a compact state to a more extended conformation, probably due to the stacking of calixarene molecules in the solution. Results also show the importance of making a proper choice of the system under consideration.Junta de Andalucía P08-FQM-03623, P12-FQM-110

Use of Ionic Liquids-like Surfactants for the Generation of Unilamellar Vesicles with Potential Applications in Biomedicine

The goal of this work is to understand the influence of the counterion nature on the organized systems formed by 1,4-bis-2-ethylhexylsulfosuccinate surfactants in aqueous solutions and how these aggregates will influence the deoxyribonucleic acid (DNA)-surfactant interactions. With this in mind, two ionic liquid-like surfactants were investigated: 1-butyl-3-methylimidazolium 1,4-bis-2-ethylhexylsulfosuccinate (bmim-AOT) and 1-hexyl-3-methylimidazolium 1,4-bis-2-ethylhexylsulfosuccinate (hmim-AOT). Measurements of dynamic light scattering, ζ-potential, transmission electron microscopy, and fluorescence and UV-visible spectroscopy were performed to study the characteristics of the vesicles formed by bmim-AOT and hmim-AOT. Regarding the determination of the interaction of the surfactants with DNA, circular dichroism was used. The results obtained showed that bmim-AOT and hmim-AOT ionic liquid-like surfactants spontaneously form unilamellar vesicles in water at very low surfactant concentrations. The characteristics of these aggregates are dependent on the length of the tail of the counterions. The length of the hydrophobic chains of the counterions also influences the DNA-surfactant interactions through hydrophobic effects.Fil: Lépori, Cristian Marcelo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Correa, Nestor Mariano. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Silber, Juana J.. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Falcone, Ruben Dario. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: López López, Manuel. Universidad de Huelva; EspañaFil: Moyá, María Luisa. Universidad de Sevilla; Españ

Influence of the surfactant degree of oligomerization on the formation of cyclodextrin: surfactant inclusion complexes

Supramolecular complexation is an attractive strategy to modulate the performance of surfactants, e.g., by host-guest interactions. Here, we investigate the interaction of single-chained, di-, tri-, and tetrameric cationic surfactants with cyclodextrins by conductivity and 1H NMR measurements, exploring the effect of increasing the number of the surfactant hydrophobic tails on the stability of cyclodextrin:surfactant inclusion complexes. The stoichiometry and the binding equilibrium constants of the different inclusion complexes were elucidated. Under the working conditions, the number of hydrophobic chains was found not to affect stoichiometry and 1:1 inclusion complexes were formed for all the surfactants investigated. The stability of the host-guest complexes decreases from single-chained to dimeric (“gemini”) surfactants, the binding following a non-cooperative mechanism. This result may be rationalized by taking into account steric constraints and electrostatic effects as well as the need to overcome the hydrophobic interactions between the chains of the same surfactant molecule. However, a further increase in the number of hydrophobic tails, from two to three to four, results in an increase in the equilibrium binding constant, K1. In this case, an increment in the number of chains capable of interaction with the cyclodextrin molecules seems to be the main factor responsible for the increase in K1. ROESY spectra show the coexistence of different types of 1:1 host-guest complexes for tri- and tetrameric surfactants.Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía P12-FQM- 1105, FQM-274 y FQM-206University of Seville 2017/1004FEDER fund

A Non-Viral Plasmid DNA Delivery System Consisting on a Lysine-Derived Cationic Lipid Mixed with a Fusogenic Lipid

The insertion of biocompatible amino acid moieties in non-viral gene nanocarriers is an attractive approach that has been recently gaining interest. In this work, a cationic lipid, consisting of a lysine-derived moiety linked to a C12 chain (LYCl) was combined with a common fusogenic helper lipid (DOPE) and evaluated as a potential vehicle to transfect two plasmid DNAs (encoding green fluorescent protein GFP and luciferase) into COS-7 cells. A multidisciplinary approach has been followed: (i) biophysical characterization based on zeta potential, gel electrophoresis, small-angle X-ray scattering (SAXS), and cryo-transmission electronic microscopy (cryo-TEM); (ii) biological studies by fluorescence assisted cell sorting (FACS), luminometry, and cytotoxicity experiments; and (iii) a computational study of the formation of lipid bilayers and their subsequent stabilization with DNA. The results indicate that LYCl/DOPE nanocarriers are capable of compacting the pDNAs and protecting them efficiently against DNase I degradation, by forming Lα lyotropic liquid crystal phases, with an average size of ~200 nm and low polydispersity that facilitate the cellular uptake process. The computational results confirmed that the LYCl/DOPE lipid bilayers are stable and also capable of stabilizing DNA fragments via lipoplex formation, with dimensions consistent with experimental values. The optimum formulations (found at 20% of LYCl content) were able to complete the transfection process efficiently and with high cell viabilities, even improving the outcomes of the positive control Lipo2000*

Metallo-Liposomes Derived from the [Ru(bpy)3]2+ Complex as Nanocarriers of Therapeutic Agents

The obtaining of nanocarriers of gene material and small drugs is still an interesting research line. Side-effects produced by the toxicity of several pharmaceutics, the high concentrations needed to get therapeutic effects, or their excessive use by patients have motivated the search for new nanostructures. For these reasons, cationic metallo-liposomes composed by phosphatidylcholine (PC), cholesterol (CHO) and RuC1C19 (a surfactant derived from the metallic complex [Ru(bpy)3]2+) were prepared and characterized by using diverse techniques (zeta potential, dynamic light scattering and electronic transmission microscopy –TEM-). Unimodal or bimodal populations of spherical aggregates with small sizes were obtained depending on the composition of the liposomes. The presence of cholesterol favored the formation of small aggregates. ct-DNA was condensed in the presence of the liposomes investigated. In-vitro assays demonstrated the ability of these nanoaggregates to internalize into different cell lines. A positive gene transfection into human bone osteosarcoma epithelial cells (U2OS) was also observed. The RuC1C19 surfactant was used as sensor to quantify the binding of DNA to the liposomes. Doxorubicin was encapsulated into the metallo-liposomes, demonstrating their ability to be also used as nanocarriers of drugs. A relationship between then encapsulation percentage of the antibiotic and the composition of the aggregates has been established.Junta de Andalucía 2019/FQM-206, 2019/FQM-274Ministerio de Ciencia e Innovación RTI2018-100692-BI00, PI-0005-2018, P18-RT-127

Host-guest interactions between cyclodextrins and surfactants with functional groups at the end of the hydrophobic tail

The aim of this work was to investigate the influence of the incorporation of substituents at the end of the hydrophobic tail on the binding of cationic surfactants to α-, β-, and -cyclodextrins. The equilibrium binding constants of the 1:1 inclusion complexes formed follow the trend K1(α-CD)>K1(β-CD)>>K1(-CD), which can be explained by considering the influence of the CD cavity volume on the host-guest interactions. From the comparison of the K1 values obtained for dodecyltriethylammonium bromide, DTEAB, to those estimated for the surfactants with the substituents, it was found that the incorporation of a phenoxy group at the end of the hydrocarbon tail does not affect K1, and the inclusion of a naphthoxy group has some influence on the association process, slightly diminishing K1. This makes evident the importance of the contribution of hydrophobic interactions to the binding, the length of the hydrophobic chain being the key factor determining K1. However, the presence of the aromatic rings does influence the location of the host and the guest in the inclusion complexes. The observed NOE interactions between the aromatic protons and the CD protons indicate that the aromatic rings are partially inserted within the host cavity, with the cyclodextrin remaining close to the aromatic rings, which could be partially intercalated in the host cavity. To the authors´ knowledge this is the first study on the association of cyclodextrins with monomeric surfactants incorporating substituents at the end of the hydrophobic tai