A new device for the generation of microbubbles

In this paper we present a new method for the production of bubble-liquid suspensions (from now on BLS) composed of micron-sized bubbles and with gas to liquid volume ratios larger than unity. We show that the BLS gas fraction ʎ=Qg and Q1 , being Qg and Q1 the flow rates of gas and liquid, respectively, is controlled by a dimensionless parameter which accounts for the ratio of the gas pressure inside the device to the liquid viscous pressure drop from the orifices where the liquid is injected to the exit, where the BLS is obtained. This parameter permits the correct scaling of the BLS gas volume fraction of all the experiments presented

Spatial and temporal analysis (2009–2020) of the biological parameters, abundance and distribution of Trachurus mediterraneus (Steindachner, 1868) in the Western Mediterranean

Trachurus mediterraneus is captured as by catch by the fishing fleet in the Spanish Mediterranean and usually landed as the global category of Trachurus spp., consequently there is a prominent lack of biological data on this species. The knowledge of the spatial and temporal evolution of its distribution, abundance and main biological parameters is essential to achieve a proper management and sustainable exploitation. Data collected in the MEDiterranean International Acoustic Survey (MEDIAS) 2009–2020 time series, carried out in July, has been analyzed to determine the evolution of the main ecological aspects of T. mediterraneus in two GFCM management units: Northern Spain (GSA06) and Northern Alboran Sea (GSA01). The results suggest a possible neritic distribution of T. mediterraneus, mainly concentrated at depths less than 60 m in GSA01 and up to 105 m in GSA06, as well as the existence of significant differences in abundance and length frequency distributions among GSAs. Furthermore, preliminary results regarding T. mediterraneus age and growth seemed to indicate a faster growth during the first two years in GSA01 than in GSA06. In both areas, potential changes in the life history traits of this species were evidenced, with a decreasing trend in the size at first maturity and condition factor over the years. Finally, five persistent distribution areas were located along the study area, highlighting Málaga Bay as a possible recruitment ground. The relevance of this study lies in the growing need for robust and current biological data of intermediate species in the marine food web and it contributes to the global purpose of achieving an integrated management of fishery resources.Versión del editor1,58

Glutamate and Brain Glutaminases in Drug Addiction

Glutamate is the principal excitatory neurotransmitter in the central nervous system and its actions are related to the behavioral effects of psychostimulant drugs. In the last two decades, basic neuroscience research and preclinical studies with animal models are suggesting a critical role for glutamate transmission in drug reward, reinforcement, and relapse. Although most of the interest has been centered in post-synaptic glutamate receptors, the presynaptic synthesis of glutamate through brain glutaminases may also contribute to imbalances in glutamate homeostasis, a key feature of the glutamatergic hypothesis of addiction. Glutaminases are the main glutamate-producing enzymes in brain and dysregulation of their function have been associated with neurodegenerative diseases and neurological disorders; however, the possible implication of these enzymes in drug addiction remains largely unknown. This mini-review focuses on brain glutaminase isozymes and their alterations by in vivo exposure to drugs of abuse, which are discussed in the context of the glutamate homeostasis theory of addiction. Recent findings from mouse models have shown that drugs induce changes in the expression profiles of key glutamatergic transmission genes, although the molecular mechanisms that regulate drug-induced neuronal sensitization and behavioral plasticity are not clear.This work was financially supported by Grants RD12/0028/0013 (JM) and RD12/0028/0001 (FRF) of the RTA RETICS network from the Spanish Health Institute Carlos III, Grant SAF2015-64501-R from the Spanish Ministry of Economy and Competitivity (to JM and JMM) and Excellence Grant CVI-6656 (Regional Andalusian government) (to JM)

Instructional Changes Adopted for an Engineering Course: Cluster Analysis on Academic Failure

As first-year students come from diverse backgrounds, basic skills should be accessible to everyone as soon as possible. Transferring such skills to these students is challenging, especially in highly technical courses. Ensuring that essential knowledge is acquired quickly promotes the student’s self-esteem and may positively influence failure rates. Metaphors can help do this. Metaphors are used to understand the unknown. This paper shows how we made a turn in student learning at the University of Almeria. Our hypothesis assumed that metaphors accelerate the acquisition of basic knowledge so that other skills built on that foundation are easily learned. With these goals in mind, we changed the way we teach by using metaphors and abstract concepts in a computer organisation course, a technical course in the first year of an information technology engineering degree. Cluster analysis of the data on collective student performance after this methodological change clearly identified two distinct groups. These two groups perfectly matched the before and after scenarios of the use of metaphors. The study was conducted during 11 academic years (2002/2003 to 2012/2013). The 475 observations made during this period illustrate the usefulness of this change in teaching and learning, shifting from a propositional teaching/learning model to a more dynamic model based on metaphors and abstractions. Data covering the whole period showed favourable evolution of student achievement and reduced failure rates, not only in this course, but also in many of the following more advanced courses.The paper is structured in five sections. The first gives an introduction, the second describes the methodology. The third section describes the sample and the study carried out. The fourth section presents the results and, finally, the fifth section discusses the main conclusions

Influencia de las nuevas tecnologías en los resultados de la asignatura “Fundamentos de Química” en la Ingeniería Técnica Industrial

En la titulación de Ingeniería Técnica Industrial de la Universidad de Jaén se ha ido implantando los créditos ECTS en todas las asignaturas, empezando en 2005 con las del primer curso, para concluir en 2007 con toda la Titulación. Aquí se presenta la parte de la experiencia correspondiente a la asignatura de Fundamentos de Química.El programa es básicamente el mismo aunque hay una reducción del tiempo del profesor dedicado a las clases presenciales. Esta circunstancia llevó al profesorado que imparte Fundamentos de Química en la Ingeniería Técnica Industrial, a comenzar a usar las nuevas tecnologías enfocadas a la puesta en práctica nuevos instrumentos docentes, tratando de mejorar la calidad del proceso de enseñanza y aprendizaje.En esta comunicación se exponen los objetivos de partida para la elaboración de guías didácticas como instrumento base para el desarrollo del proceso docente, la metodología y los resultados en la evaluación de los alumnos

On-Surface Thermal Stability of a Graphenic Structure Incorporating a Tropone Moiety

On-surface synthesis, complementary to wet chemistry, has been demonstrated to be a valid approach for the synthesis of tailored graphenic nanostructures with atomic precision. Among the different existing strategies used to tune the optoelectronic and magnetic properties of these nanostructures, the introduction of non-hexagonal rings inducing out-of-plane distortions is a promising pathway that has been scarcely explored on surfaces. Here, we demonstrate that non-hexagonal rings, in the form of tropone (cycloheptatrienone) moieties, are thermally transformed into phenyl or cyclopentadienone moieties upon an unprecedented surface-mediated retro–Buchner-type reaction involving a decarbonylation or an intramolecular rearrangement of the CO unit, respectivel

Rickettsia parkeri in Amblyomma triste from Uruguay

Our goal was to detect whether spotted fever group Rickettsia are found in the suspected vector of rickettsioses, Amblyomma triste, in Uruguay. Rickettsia parkeri was detected in A. triste, which suggests that this species could be considered a pathogenic agent responsible for human rickettsioses in Uruguay

Cinética de biodegradación de un nonilfenol polietoxilado en agua de río

[ES] En el presente trabajo se aborda el estudio cinético del proceso de biodegradación de uno de los tensioactivos sintéticos más consumidos en el mundo a nivel industrial, los alquilfenoles polietoxilados (APEO), en un medio natural como es el agua de río. El método de ensayo empleado ha sido el "River die away test" y para el análisis de la materia tensioactiva se ha empleado cromatografía líquida de alta resolución. El modelo cinético propuesto por los autores, ha sido aplicado a los datos de biodegradación obtenidos bajo diversas condiciones de temperatura y concentración inicial de materia activa. Los resultados muestran que el modelo se ajusta tanto a situaciones de periodos de inducción breves como prolongados y permite obtener parámetros cinéticos de interés como son, el contenido en substrato no biodegradable y la velocidad máxima de crecimiento microbiano.Manzano Quiñones, MA.; Perales Vargas-Machuca, JA.; Sales Márquez, D.; Quiroga Alonso, JM. (1998). Cinética de biodegradación de un nonilfenol polietoxilado en agua de río. Ingeniería del Agua. 5(3):27-32. https://doi.org/10.4995/ia.1998.2763SWORD273253Bayley, J. y Ollis, D. (1980) Biochemical Engineering Fundamentals. Ed. McGraw Hill.Gaden, E. (1959) Fermentation process kinetics. J. Biochem. Microbiol. Tech. Eng, 1. pp 63-70Larson, R. y Payne, A. (1981) Fate of the benzene ring of linear alkylbenzene sulfonate in natural waters. Appl. Environ. Microbiol, 41, 3, pp 621 -627.Okpokwasili, G.C. y Olisa, A.O. (1991) River-water biodegradation of surfactants in liquid detergents and shampoos. Water Research, 25.11, pp 1425-1429.Quiroga, J.M. y Sales, D. (1989) Ensayos de degradación con cepas puras de microorganismos. Ingeniería Química. Junio, pp 179-183.Quiroga, J.M. y Sales, D. (1991) Surfactant biodegradation in sea water. Tenside Surfactants Detergents, 28, 3, pp 200-203.Raymond, A. (1996) The global outlook for surfactant from a U.S. perspective. 4th World Surfactant Congress, Vol. 1, pp 21-36.Romero, L.; Perez, M.; Sales, D. (1997) Degradation kinetics of distillery wastewaters by immobilized anaerobic mixed cultures. The 8th International Conference on Anaerobic Digestion (AD-97). IAWQ. Japan, May.Schröder, H, Fr. (1993) Surfactants: non-biodegradable, significant pollutants in sewage treatment plant effluents. Journal of Chromatography, 647, pp 219-234.Sivak, A., Goyer, M. y Perwak, J. (1982) Environmental and human aspects of commercially important surfactants. Solution behaviour of surfactants. Ed. Plenum Publishing Corp.Vol 1, pp 161-188.Wang, Z. y Fingas, M. (1993) Rapid separation of non-ionic surfactants of polyethoxylated octylphenol and determination of ethylene oxide oligomer distribution by C1 column reversed-phase liquid chromatography. Journal of Chromatography, 637, pp 145-156.Yoshimura, K. (1986) Biodegradation and fish toxicity of nonionic surfactants. Japan Surface Active Agent Association. 63, 12, pp 1590-159