2,501 research outputs found
About Helices and Solvents: VCD and more
Intermolecular forces drive self-organization of molecules, which is ultimately the origin of most the physical and chemical phenomena in Nature. Molecules able to interact themselves by non-covalent forces, as hydrogen bonding and/or hydrophobic attractions, usually form macrostructures in condensed phases (solid, solution). The properties of these aggregates depend of three main factors: the structural and chemical features of the molecules, the nature of intermolecular forces and the environment. The first two drive aggregation in solid state, while in solution the role of the solvent become determinant as it can induce a variety of structural effects on the aggregation behaviour of the solute. In the case of chiral molecules, this property is transferred to the aggregates and supramolecular chirality appears.
Here we present our research on chiral molecules that self-organize in solution forming helical structures. We use VCD as the main chiroptical tool, but also supported by other chiroptical spectroscopies (ECD, ROA) and theoretical modelling. In our first steps, we studied the effect of modulating the environmental settings on the helices. Thus, helix handedness was proved highly and reversibly dependent on factors as pH or ionic strength in peptide-mimetic hydrogelators. We also observe how the initial conditions (concentration, temperature) were capable of controlling the helix structure of oligo-p-phenylene-based polymers towards kinetic or thermodynamics pathways. Besides, the structure of the helices can also be the consequence of direct solvent-solute interactions. In this way, we have demonstrated that an achiral solvent can act as a template for chiral organization of N-heterotriangulenes-based organogelators, thus showing the different levels of complexity of the hierarchical organization of supramolecular polymers.
But the solvent-helix interactions can be bidirectional. As a nice example, we recorded chiral signals which can be only assigned to the organization of the solvent molecules around helical aggregates of phenylglycine functionalized poly(phenylacetylene)s. The solvent molecules thus form a first solvation shell to which the helix chirality is transferred. The helices would act therefore as a template of the solvent molecules, and the chirality of this external helix would be fully controlled by the solute.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Chiroptical Spectroscopy of C3 Molecules
The relevance of molecules with C3 symmetry comes from the fact of many of them, upon assembling as columnar helical macromolecules, are ideal platform for electro-optical devices, for example as liquid crystals. The properties of these devices are highly dependent of the structure of the bulk aggregates, and consequently they can be controlled by modifying the position and nature of the stereocenters in the molecular building blocks.
In this work we present an electronic and vibrational chiroptical study on a series of star-shaped molecules based on the octopolar C3-symmetric 1,3,5-(phenylene-ethynylene)-benzene block.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec
El diálogo asíncrono docente‐investigador, como proceso de construcción colaborativa del conocimiento
Para asumir responsablemente los cambios educativos que demanda la Reforma Académica, es preciso que los profesores adopten un modelo profesional de la docencia. En la mayoría de los casos, los profesores del IPN, son profesionales de la disciplina que imparten pero van construyendo su concepción de la docencia a partir de su propia práctica y de algunos cursos generales sobre didáctica; sin embargo, esto no suele convertirlos en profesionales de la docencia. Según Romberg (1988), los profesionales se distinguen por usar un conocimiento específico; en el caso de la docencia hay por lo menos 4 tipos de conocimientos que el docente debe poseer: el conocimiento de su propia disciplina; el conocimiento de la pedagogía; el conocimiento del contenido desde una perspectiva pedagógica y el conocimiento sobre cómo administrar una situación educativa. En el caso de matemáticas, estos conocimientos se integran en una disciplina: la matemática educativa. Para acercar a los profesores a este conocimiento especializado, en particular a los resultados de las investigaciones, se diseñó el Seminario Repensar las Matemáticas (SRM). En el SRM, uno de los medios de comunicación es un foro‐e de discusión que permite establecer un diálogo entre el investigador y el docente a partir de sus resultados de investigación, El foro constituye un espacio de profesionalización, donde se construye un conocimiento profesional y se fortalecen los procesos de colegialidad. Más que atender al análisis cuantitativo de las participaciones, este trabajo resalta la importancia de la calidad del diálogo que se establece entre el profesor y el investigador a través de diferentes categorías de análisis que dan cuenta del tipo de intervención y de los niveles y las fases de la discusión. Del análisis realizado se desprende que los foros de discusión asíncronos constituyen un medio que permite describir la evolución de la calidad de la interacción docente‐investigador en la construcción colaborativa de conocimiento. Además, la participación de los profesores en los foros‐e contribuye a la construcción del conocimiento que requiere para su profesionalización
ARTEMISA: Architecture of an eco-driving assistant based on the anticipation
This paper presents the architecture of an eco driving assistant. The assistant evaluates the fulfil ment of classic eco-driving advices such as: main tain a constant speed, driving at high gear, slow
down smoothly and so on. In addition, the assistant
issues advices based on the anticipation. Anticipa tion is the key of eco-driving. The assistant is ca pable of detecting traffic signs beforehand and it
checks if the speed is suitable for not having to
slow down sharply. In addition, the system propos es an optimal average speed according to the con ditions of the road.
To model the environment where the vehicle is
moving, we use an Android mobile device. These
devices are ideal due to to their multiple network
connections (Bluetooth, UTMS and WIFI) and sen sors (camera, acceleration sensor, GPS and so on).
To obtain the vehicle’s parameters (speed, fuel
consumption, RPM, etc.), we use the diagnostic
port (OBD2).
The proposed system can improve fuel consump tion and safety. In addition, it is independent of the
type of vehicle.Ministerio de Ciencia e Innovación TIN2009-14378-C02-02European Union REA FP7/2007-2013 n° 286533Ministerio de Ciencia e Innovación HAUS IPT-2011-1049-43000
Anestesia para cirugía bariátrica en paciente con síndrome de Prader-Willy: reporte de un caso
ResumenEl síndrome de Prader-Willi es un desorden genético caracterizado por hipotonía, obesidad, baja estatura, retraso mental, hiperfagia, hipogonadismo y expectativa de vida reducida.Describimos el caso de una paciente de 31 años con antecedente de síndrome de Prader-Willi, programada para realización de cirugía bariátrica. Se revisan las consideraciones anestésicas, haciendo énfasis en las complicaciones perioperatorias secundarias a este síndrome.AbstractPrader-Willi syndrome is a genetic disorder characterized by hypotonia, obesity, short stature, mental retardation, hyperphagia, hypogonadism and low life expectancy.We describe the case of a 31-year-old female patient with Prader-Willi syndrome scheduled for bariatric surgery. Anesthetic considerations are reviewed highlighting perioperative complications associated with this syndrome
New generalized apostol-frobenius-euler polynomials and their matrix approach
In this paper, we introduce a new extension of the generalized Apostol-Frobenius-Euler polynomials ℋn[m−1,α](x; c,a; λ; u). We give some algebraic and differential properties, as well as, relationships between this polynomials class with other polynomials and numbers. We also, introduce the generalized Apostol-Frobenius-Euler polynomials matrix ????[m−1,α](x; c,a; λ; u) and the new generalized Apostol-Frobenius-Euler matrix ????[m−1,α](c,a; λ; u), we deduce a product formula for ????[m−1,α](x; c,a; λ; u) and provide some factorizations of the Apostol-Frobenius-Euler polynomial matrix ????[m−1,α](x; c,a; λ; u), which involving the generalized Pascal matrix
“El poder de los introvertidos”: lidiar con la introversión en el aula de inglés a través de la comunicación y aprendizaje cooperativo
During my practice period in a High School in the outskirts of Zaragoza, I noticed that there was a high level of introverted students who struggled to participate in oral activities. The following dissertation has the objective to increase verbal engagement of introverted learners in the English classroom while covering their needs. For that, cooperative learning and the use of technologies will play an important role to motivate these students to speak up within a safe environment. I also took as a reference the guidelines provided by the Aragonese Curriculum (ORDEN ECD/489/2016, 26th may). This unit proposal, following the sequence of the Project-Based-Language-Learning approach, deals with the importance of self-awareness to be aware of one’s introverted or extroverted personality and analyse and express one’ emotions and preferences as a consequence of our personality. Accordingly, they will enhance their empathy and tolerance through exchanging opinions and stances with their classmates. By building self awareness skills, students will adapt their lifestyle to their actual needs, having a positive impact in their learning process. To carry out the activities with success, I have made use of a wide range of scaffolding techniques and teaching strategies that will serve to guide their learning, to boost thinking before sharing and to develop their communicative competence within a comfortable atmosphere.<br /
De la literatura al cine: análisis estructural y comparativo del cuento "No oyes ladrar los perros" de Juan Rulfo y el Guión cinematográfico ¿No oyes ladrar los perros? de Carlos Fuentes
En la presente investigación el lector encontrará un estudio estructural y comparativo de dos textos: el cuento “No oyes ladrar los perros”, de Juan Rulfo y el guión cinematográfico ¿No oyes ladrar los perros?, de Carlos Fuentes
La inquietud por llevar a cabo una investigación de esta índole fue porque hace algunos años dentro de las asignaturas de la licenciatura de Letras Latinoamericanas, leímos y analizamos la obra de Juan Rulfo, aunque debo reconocer que desde mi infancia mi padre me ponía a practicar la lectura con el libro El llano en llamas. En los cuentos de Rulfo vi una riqueza literaria impresionante, es decir, la forma de escribir de este autor me pareció tan simple, pero al mismo tiempo tan compleja que al enterarme, tiempo después, que existía una película del cuento “No oyes ladrar los perros”, y luego de verla creció mi interés por conocer el proceso de transformación para llevar un cuento tan corto de seis páginas a una película de hora y media
An extended chronicle discovery approach to find temporal patterns between sequences
Sequences of events describing the behavior and
actions of users or systems can be collected in sev eral domains. An episode is a collection of events
that occurs relatively close to each other in a given
partial order. Also, chronicles are a special type of
temporal patterns, where temporal orders of events
are quantified with numerical bounds and reflect
the temporal evolution of the system over the time.
In this paper, the problem of finding rules for de scribing or predicting the behavior of the sequences
with the intention of characterizing some interest ing tasks is considered. Obtaining these patterns is
the main objective of this work, where an automatic
method to learn relevant and discriminating chron icles is proposed. The method extends existing al gorithms that have been proposed to find frequent
episodes/chronicles in a single event sequence to
the case of multiple sequences.Ministerio de Economía y Competitividad TIN2009-14378-C02-01 (ARTEMISA)Junta de Andalucía TIC-8052 (Simon
SEQUENTIAL INDUCTION OF CHIRALITY IN POLY(PHENYLACETYLENE)S
Several hierarchical levels of chirality have been detected in functionalized poly(phenylacetylene)s (PPA).1 In this work we have studied the chirality induction throughout these levels in PPA functionalized with phenylglycine methyl ester groups, Fig. 1.2 These pendant groups force the PPA chain to lose its planar all-transoid shape to form helical structures. The chiral seed of the pendants, [(R)- or (S)-], dictates the preferent handedness of the helices, both the internal polyacetylene helical covalent backbone and the external helix formed by the side pendants which forms a complementary helix or counter-helix. In this work, we afford a full assessment of the interconnection between stereocenter and helix sources of chirality and the action of these polymers as chiral templates of other supra-molecular structures with inherited chiral properties. We then used VCD spectroscoy to demonstrate the chiral induction from the stereogenic centers to the backbone helix and from this to the pendant helix, which are largely promoted by two mechanisms: steric effects and hydrogen bonding. In addition, the VCD spectra supported that the helical setup of the pendants induces the solvent DMSO molecules to adopt a solvation helix around the polymer, thus proving how an achiral solvent becomes chirally organized owing to the template effect of the covalent polymer helices. A similar effect was observed in DMSO solutions of the monomeric units. Interestingly, this resulted in opposite helical sense to the one observed in the polymer with identical enantiomeric form.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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