1,484 research outputs found
Hydrotreating of Guaiacol and Acetic Acid Blends over Ni2P/ZSM-5 Catalysts: Elucidating Molecular Interactions during Bio-Oil Upgrading
[EN] Catalytic hydrodeoxygenation (HDO) is an effective technology for upgrading pyrolysis bio-oils. Although, in the past years, this process has been extensively studied, the relevance of the cross-reactivity between the numerous chemical components of bio-oil has been scarcely explored. However, molecular coupling can be beneficial for improving the bio-oil characteristics. With the aim of gaining a better understanding of these interactions, this work investigates the catalytic hydrodeoxygenation of mixtures of two typical components of pyrolysis bio-oils: guaiacol and acetic acid. The catalytic tests were carried out employing a bifunctional catalyst based on nickel phosphide (Ni2P) deposited over a commercial nanocrystalline ZSM-5 zeolite. The influence of both hydrogen availability and temperature on the activity and product distribution, was evaluated by carrying out reactions under different H2 pressures (40¿10 bar) and temperatures (between 260 and 300 °C). Using blends of both substrates, a partial inhibition of guaiacol HDO occurred because of the competence of acetic acid for the catalytic active sites. Nevertheless, positive interactions were also observed, mainly esterification and acylation reactions, which could enhance the bio-oil stability by reducing acidity, lowering the oxygen content, and increasing the chain length of the components. In this respect, formation of acetophenones, which can be further hydrogenated to yield ethyl phenols, is of particular interest for biorefinery applications. Increasing the temperature results in an increment of conversion but a decrease in the yield of fully deoxygenated molecules due to the production of higher proportion of catechol and related products. Additional experiments performed in the absence of hydrogen revealed that esterification reactions are homogeneously self-catalyzed by acetic acid, while acylation processes are mainly catalyzed by the acidic sites of the zeolitic support.The authors thank to the Spanish “Ministry of Economy and Competiveness” for their financial support through the project CATPLASBIO (CTQ2014-60209-R), as well as to the “Regional Government of Madrid” and European Structural Funds for the RESTOENE2 (S2013/MAE-2882) project
Tuning the properties of ionic liquids by mixing with organic solvents: The case of 1-butyl-3-methylimidazolium glutamate with alkanols
Binary liquid mixtures of 1-butyl-3-methylimidazolium glutamate acid ([bmim][glu]) with alkanols (1-propanol, isobutanol and 1,2-propanediol) are studied in the full composition range as a function of temperature using a combined experimental and computational chemistry approach. Experimental thermophysical information as well as derived excess and mixing properties allowed to characterize these complex liquid mixtures in terms of deviation from ideality as well their relationships with the developed intermolecular forces and changes with the type of considered alkanols. Theoretical studies using quantum chemistry and classical molecular dynamics simulations provided nanoscopic characterization on the studied fluids, with particular attention to the extension and nature of hydrogen bonding and its effects on molecular arrangements and mixed fluids’ properties. The reported study provides a micro and macroscopic characterization of the considered aminoacid-based ionic liquid mixtures, thus contributing to the knowledge of sustainable ionic liquid systems mixed with organic solvents for fine tuning properties and developing task specific applications.Shiraz University of Technology and Ministerio de Ciencia, Innovación y Universidades (Spain, project RTI2018-101987-B-I00)
Assessment of satisfaction in patients after hysterectomy by myomatous uterus
Objetivo: el objetivo de este estudio es evaluar los resultados, en
cuanto a calidad de vida, de aquellas pacientes que han sido sometidas
a una histerectomía por útero miomatoso. Material y métodos: se realiza
una encuesta sobre calidad de vida a todas las pacientes sometidas
a histerectomía con indicación de útero miomatoso, en un hospital de
tercer nivel dentro de la red de hospitales del servicio de salud de la
Comunidad de Madrid, en el año 2010. Resultados: Se identificaron un
total de 152 pacientes a las que se les había realizado una histerectomía
por útero miomatoso, de las cuales contestaron la encuesta un total de
112 (74%) pacientes. Cuando se les preguntó a las pacientes si había
mejorado su calidad de vida tras la realización de la histerectomía, un
78’6% (88/112) respondió afirmativamente, un 17% (19/112) refirió tener
la misma calidad de vida, y un 4’4% (5/112) respondió que su calidad
de vida había empeorado tras la intervención. Conclusiones: las pacientes
sometidas a una histerectomía por útero miomatoso presentan
un alto grado de satisfacción tras la cirugía, comunicando en su mayoría
una mejora en cuanto al dolor pélvico previo a la cirugía, y una mejor
calidad de vida tras la intervenciónObjective: the objective of this study is to evaluate the results, in
terms of quality of life of those patients who have undergone hysterectomy
for fibroid uterus. Material and methods: we performed a survey
on quality of life for all patients undergoing hysterectomy with uterine fibroid
indication in a tertiary care hospital within the hospital network of
the health service of the Community of Madrid, in the year 2010. Results:
a total of 152 patients which had undergone a hysterectomy for uterine
myoma, which answered the survey a total of 112 (74%) patients. When
asked patients if they had improved their quality of life after performing
a hysterectomy, a 78’6% (88/112) responded affirmatively, 17% (19/112)
reported having the same quality of life, and 4.4% (5/112) responded that
their quality of life had worsened after surgery. Conclusions: patients
undergoing a hysterectomy for uterine fibroids have a high degree of satisfaction
after the surgery, communicating mostly an improvement in pelvic
pain prior to surgery, and improved quality of life after surger
Type II supernova spectral diversity, II: spectroscopic and photometric correlations
We present an analysis of observed trends and correlations between a large range of spectral and photometric parameters of more than 100 type II supernovae (SNe II), during the photospheric phase. We define a common epoch for all SNe of 50 days post-explosion, where the majority of the sample is likely to be under similar physical conditions. Several correlation matrices are produced to search for interesting trends between more than 30 distinct light-curve and spectral properties that characterize the diversity of SNe II. Overall, SNe with higher expansion velocities are brighter, have more rapidly declining light curves, shorter plateau durations, and higher 56Ni masses. Using a larger sample than previous studies, we argue that "Pd" - the plateau duration from the transition of the initial to "plateau" decline rates to the end of the "plateau" - is a better indicator of the hydrogen envelope mass than the traditionally used optically thick phase duration (OPTd: explosion epoch to end of plateau). This argument is supported by the fact that Pd also correlates with s 3, the light-curve decline rate at late times: lower Pd values correlate with larger s 3 decline rates. Large s 3 decline rates are likely related to lower envelope masses, which enables gamma-ray escape. We also find a significant anticorrelation between Pd and s 2 (the plateau decline rate), confirming the long standing hypothesis that faster declining SNe II (SNe IIL) are the result of explosions with lower hydrogen envelope masses and therefore have shorter Pd values.Fil: Gutiérrez, Claudia P.. Universidad de Chile; Chile. University of Southampton; Reino Unido. European Southern Observatory Santiago; Chile. Millennium Institute Of Astrophysics; ChileFil: Anderson, Joseph P.. European Southern Observatory Santiago; ChileFil: Hamuy, Mario. Millennium Institute Of Astrophysics; Chile. Universidad de Chile; ChileFil: González Gaitan, Santiago. Universidad de Chile; Chile. Universidade de Lisboa; Portugal. Millennium Institute Of Astrophysics; ChileFil: Galbany, Lluis. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Dessart, Luc. Universidad de Chile; ChileFil: Stritzinger, Maximilian D.. University Aarhus; DinamarcaFil: Phillips, Mark M.. Las Campanas Observatory; ChileFil: Morrell, Nidia. Las Campanas Observatory; ChileFil: Folatelli, Gaston. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin
La formación del concepto de función en alumnos de educación media superior
En este artículo se describe la realización de un taller cuyo diseño responde al marco de una investigación en proceso, que explora los saberes que sobre el concepto de función tienen los alumnos de educación media superior (EMS) y pretende analizar los efectos que presenta la puesta en escena de situaciones didácticas sobre la formación del concepto de función. En la primera etapa de la investigación se están explorando dichos saberes en 30 alumnos de EMS y 10 de los primeros semestres de la licenciatura en matemáticas en Acapulco, Guerrero, México. También se han diseñado situaciones didácticas para abordar este concepto, a fin de que se instrumenten en la escuela. Con estos avances se estructuró el taller para interesados en este campo y realizado en Relme 17 con la participación de siete profesores
Insights on biodiesel blends with alkanol solvents
Thermophysical properties of mixtures of fatty acid esters with alkanols were measured in the whole composition range as a function of temperature for understanding features of biodiesel blends. Excess and mixing properties calculated from experimental measurements allowed to quantify and analyze the intermolecular forces in the considered systems. Likewise, molecular modelling studies using quantum chemistry and classical molecular dynamics simulations led to a detailed characterization of these systems at the nanoscopic level. The nature of hydrogen bonding in these liquid mixtures was particularly analyzed from macroscopic properties and theoretical modelling results. The reported experimental and computational study allowed to infer the relationships between the intermolecular forces and additional microscopic features and the mixtures macroscopic properties, which are relevant for the development and characterization of biodiesels. The non-ideality behavior of the studied systems shows relevant changes in hydrogen bonding structuring upon mixing, with the fatty acid esters largely disrupting the alcohols self-association, although ester – alcohol hydrogen bonding is developed, this type of interactions is remarkably weaker than those for alcohols. Therefore, the studied biodiesel blends macroscopic properties may be tuned and controlled through the amount of alcohols in the mixtures and rooted on its effect on hydrogen bonding.Shiraz University of Technology (Iran), Junta de Castilla y León (Spain, project BU094G18) and Ministerio de Ciencia, Innovación y Universidades (Spain, project RTI2018-101987-B-I00) for supporting this project. We also acknowledge SCAYLE (Supercomputación Castilla y León, Spain) for providing supercomputing facilities
The contribution of Trichoderma to balancing the costs of plant growth and defense
Trichoderma is a fungal genus of cosmopolitan distribution and high biotechnological value, with several species currently used as biological control agents. Additionally, the enzyme systems of the fungus are widely applied in industry. Species of Trichoderma protect plants against the attack of soil-borne plant pathogens by competing for nutrients and inhibiting or killing plant pathogenic fungi and oomycetes, through the production of antibiotics and/or hydrolytic enzymes. In addition to the role of Trichoderma spp. as biocontrol agents, they have other benefi cial effects on plants, including the stimulation of plant defenses and the promotion of plant growth. In this review, we focus on the complex plant defense signaling network that allows the recognition of fungi as non-hostile microbes, including microbial-associated molecular patterns (MAMPs), damageassociated molecular patterns (DAMPs) and secreted elicitors. We also examine how fungal interactions with plant receptors can activate induced resistance by priming and balancing plant defense and growth responses. Our observations are integrated into a model describing Trichoderma-plant hormone signaling network interactions. [Int Microbiol 2013; 16(2):69-80]Keywords: Trichoderma spp.; plant–Trichoderma symbiosis; Arabidopsis thaliana; phytohormone networking 
Functional Analysis of the Trichoderma harzianum nox1 Gene, Encoding an NADPH Oxidase, Relates Production of Reactive Oxygen Species to Specific Biocontrol Activity against Pythium ultimum
[EN] The synthesis of reactive oxygen species (ROS) is one of the first events following pathogenic interactions in eukaryotic cells, and NADPH oxidases are involved in the formation of such ROS. The nox1 gene of Trichoderma harzianum was cloned, and its role in antagonism against phytopathogens was analyzed in nox1-overexpressed transformants. The increased levels of nox1 expression in these transformants were accompanied by an increase in ROS production during their direct confrontation with Pythium ultimum. The transformants displayed an increased hydrolytic pattern, as determined by comparing protease, cellulase, and chitinase activities with those for the wild type. In confrontation assays against P. ultimum the nox1-overexpressed transformants were more effective than the wild type, but not in assays against Botrytis cinerea or Rhizoctonia solani. A transcriptomic analysis using a Trichoderma high-density oligonucleotide (HDO) microarray also showed that, compared to gene expression for the interaction of wild-type T. harzianum and P. ultimum, genes related to protease, cellulase, and chitinase activities were differentially upregulated in the interaction of a nox1-overexpressed transformant with this pathogen. Our results show that nox1 is involved in T. harzianum ROS production and antagonism against P. ultimumSIResearch project funding was from the Junta de Castilla y León (GR67) and the Spanish Ministry of Science and Innovation (AGL2008-0512/AGR and AGL2009-13431
- …