Electrical resistivity of the Ti4O7 Magneli phase under high pressure

We have measured resistivity as a function of temperature and pressure of Ti4O7 twinned crystals using different contact configurations. Pressures over 4kbar depress the localization of bipolarons and allow the study of the electrical conduction of the bipolaronic phase down to low temperatures. For pressures P > 40 kbar the bipolaron formation transition is suppressed and a nearly pressure independent behavior is obtained for the resistivity. We observed an anisotropic conduction. When current is injected parallel to the principal axis, a metallic conduction with interacting carrier effects is predominant. A superconducting state was not obtained down to 1.2 K, although evidences of the proximity of a quantum critical point were noticed. While when current is injected non-parallel to the crystal's principal axis, we obtained a logarithmic divergence of the resistivity at low temperatures. For this case, our results for the high pressure regime can be interpreted in the framework of interacting carriers (polarons or bipolarons) scattered by Two Level Systems.Comment: 9 Revtex pages, 12 EPS figures included, submitted to The European Physical Journal B. Contact author: C. Acha (e-mail address: [email protected]

Development of alginate beads for probiotic encapsulation: influence of different parameters in the beads size

In the present study different parameters were evaluated in the formation of alginate beads by ionotropic gelation (external extrusion). The size of alginate beads was determined and results showed that needle-CaCl2 solution distance, flow rate, sodium alginate concentration, needle diameter and molecular weight of sodium alginate influenced alginate beads formation. Moreover, was concluded that needle diameter was the parameter that most influenced the beads mean size

Validación por la Comunidad Docente de una Metodología de Aprendizaje Activo para Cursos de Programación

Actas de: III Jornadas de Innovación Educativa en Ingeniería Telemática (JIE). Granada, 28-30 Octubre 2013.En este artículo se presenta y evalúa una metodología para cursos de programación, basada en el aprendizaje activo y el aprendizaje basado en proyectos. Esta metodología se centra en el trabajo continuo, día a día, del alumno. Por un lado, ofrece pautas para que los alumnos organicen su tiempo, promoviendo el autoaprendizaje y el trabajo individual. Por otro, durante el proyecto los alumnos desarrollan sus capacidades de trabajo en equipo, fomentando el desarrollo de competencias transversales como el aprendizaje colaborativo. La metodología descrita se ha aplicado durante varios cursos en una asignatura de programación en C de segundo curso de los cuatro grados de Ingeniería de Telecomunicaciones. Para poder evaluar, ajustar y mejorar el proceso de enseñanzaaprendizaje propuesto, se utilizan mecanismos de realimentación y seguimiento del alumnado y del profesorado. En este artículo, la implantación de la metodología es evaluada por 40 profesores de distintas universidades españolas que imparten asignaturas en cursos de ingeniería, con objeto de validar su aplicabilidad en otros contextos.Este trabajo ha sido financiado parcialmente por el proyecto nacional del Ministerio de Economía y Competitividad, “Espacios Educativos Especulares” - EEE (TIN2011-28308-C03-01), por el proyecto regional de la Comunidad de Madrid, “eMadrid” (S2009/TIC-1650) y por el programa de estancias postdoctorales Alianza 4 Universidades.Publicad

The role of phonological and orthographic information in lexical selection

Theoretical and Experimental Linguistic

Effect of alginate molecular weight and M/G ratio in beads properties foreseeing the protection of probiotics

"Available online 1 December 2017"Probiotics are live microorganisms that when administered in adequate amounts confer a health benefit to the host. However, to accomplish this positive influence on Human health, probiotics should survive to the passage through the upper digestive tract in large numbers to unsure a desired beneficial effect in the host. Several encapsulation methods have been used to protect probiotics. Alginate is the most used biopolymer in the production of these systems, although its performance is totally dependent of its structure and chemical characteristics. In this work, alginates with different molecular weights and different mannuronic and guluronic acid residues ratio (M/G ratio) were used in the encapsulation of Lactococcus lactis spp. cremoris (LLC) aiming the protection of this probiotic bacteria against the harsh conditions of digestion. Alginate-based beads were produced using an external gelation process (extrusion technique) where variables regarding the processing conditions and alginate chemical characteristics were studied to assess their relevance in this process aiming the most efficient encapsulation system. The most important variables influencing the size of alginate beads were the alginate concentration, alginate type (M/G ratio and molecular weight) and the nozzle diameter. Beads with sizes ranged between 1.9 and 3.0 mm were produced using different alginates. Fourier transform infrared (FTIR) spectroscopy showed relevant differences between beads produced proving the impact of different M/G ratios in the beads chemical structure. In general, low molecular weight and low M/G ratio alginate (Protanal LFR5/60) proved to produce the most well organized (according to SEM analyses), less permeable (pore diameter of 2.52 nm) and stronger alginate beads, moreover molecular weight and M/G ratio proved to be an important variable on the protection of probiotics against the harsh conditions of digestion. Produced beads proved to be efficient in the protection of probiotics (i.e. high viability), with the best performance presented by the medium and low molecular weight alginates.The author Philippe E. Ramos would like to thank the Post-doc fellowship to the national agency Fundação para a Ciência e a Tecnologia (UID/BIO/04469) and to the European Regional Development Fund (FEDER) through COMPETE 2020 e Programa Operacional Competitividade e Internacionalização (POCI-01-0145-FEDER-006684). The authors thank the FCT Strategic Project PEstOE/EQB/LA0023/2013 and the project “BioInddBiotechnology and Bioengineering for Improved Industrial and Agro-Food Processes”, ref. NORTE-07-0124-FEDER-000028 cofunded by the Programa Operacional Regional do Norte (ON.2eO Novo Norte), QREN, FEDER.info:eu-repo/semantics/publishedVersio

One Dimensional Oxygen Ordering in YBa2Cu3O(7-delta)

A model consisting of oxygen-occupied and -vacant chains is considered, with repulsive first and second nearest-neighbor interactions V1 and V2, respectively. The statistical mechanics and the diffraction spectrum of the model is solved exactly and analytically with the only assumption V1 >> V2. At temperatures T ~ V1 only a broad maximum at (1/2,0,0) is present, while for ABS(delta - 1/2) > 1/14 at low enough T, the peak splits into two. The simple expression for the diffraction intensity obtained for T << V1 represents in a more compact form previous results of Khachaturyan and Morris[1],extends them to all delta and T/V2 and leads to a good agreement with experiment. [1] A.G.Khachaturyan and J.W.Morris, Jr., Phys.Rev.Lett. 64,76(1990)Comment: 13 pages,Revtex,3 figures available upon request but can be plotted using simple analytical functions,CNEA-CAB 92/04

The Quality Reference Framework for MOOC Design

This paper introduces "The Quality Reference Framework (QRF) for the Quality of MOOCs". It was developed by the European Alliance for the Quality of Massive Open Online Courses (MOOCs), called MOOQ that could involve in the QRF finalization more than 10,000 MOOC learners, designers, facilitators and providers. The QRF consists of three dimensions: Phases, Perspectives and Roles. It includes two quality instruments: the QRF Key Quality Criteria for MOOC experts and QRF Quality Checklist for MOOC beginners

Gender congruency goes Europe: A cross-linguistic study of the gender congruency effect in Romance and Germanic languages.

Theoretical and Experimental Linguistic

Physico-chemical Characterization Of The Inclusion Complex Between A 2-propen-1-amine Derivative And β-cyclodextrin

Inclusion complexes and physical mixtures were prepared with isomeric mixture of E/Z (50:50) of 3-(4′-bromo-[1,1′-biphenyl]-4-yl)-3-(4- bromophenyl)-N,N-dimethyl-2-propen-1-amine (BBAP) and β-cyclodextrin (β-CD) in different proportions. In this study, theoretical calculations using Molecular Mechanics MM+ force field were applied to predict the structures of the inclusion complexes formed by interaction of BBAP and b-cyclodextrin. Circular dichroism, differential thermal analysis (DTA), X-ray diffraction and 13C CP/MAS NMR methods were used to characterize the inclusion complexes and provide information about the stoichiometry of the inclusion complexes. The combined spectroscopy techniques indicate the formation of a complex of BBAP/β-CD in the molar proportion of 1:1 and 1:2 by co-evaporation and no complexation was detected in the physical mixture of the compounds. © 2006 Sociedad Chilena de Química β-.503115127Bibby, D.C., Davies, N.M., Tucker, I.G., (2000) Int. J. Pharm., 197, p. 1Connors, K.A., (1995) J. Pharm. Sci., 84, p. 843Connors, K.A., Paulson, A., Toledo-Velasquez, D.J., (1988) J. Org. Chem., 53, p. 2123Dollo, G., Le Corre, P., Chollet, M., Chevanne, F., Bertault, M., Burgot, J.-L., Le Verge, R., (1999) J. Pharm. Sci., 88, p. 889Mucci, A., Schenetti, L., Vandelli, M.A., Ruozi, B., Forni, F., (1999) J. Chem. Research, (S), p. 414Keipert, S., Fedder, J., Bohm, A., Hanke, B., (1996) Int. J. Pharm., 142, p. 153Nigam, S., Durocher, G., (1999) J. Photochem. Photobiol. A: Chem., 103, p. 143De Souza, A.O., Sato, D.N., Aily, D.C.G., Duran, N., (1998) J. Antimicrob. Chemother., 42, p. 407Pereira, D.G., De Castro, S.L., Durán, N., (1998) Acta Tropica, 69, p. 205De Souza, A.O., Santos Júnior, R.R., Ferreira-Júlio, J.F., Rodrigues, J.A., Melo, P.S., Haun, M., Sato, D.N., Durán, N., (2001) Eur. J. Med. Chem., 36, p. 843De Souza, A.O., Hemerly, F.P., Busollo, A.C., Melo, P.S., Machado, G.M.C., Miranda, C.C., Santa-Rita, R.M., Durán, N., (2002) J. Antimicrob. Chemother., 50, p. 629De Conti, R., Gimenez, S.M.N., Haun, M., Pilli, R.A., De Castro, S.L., Durán, N., (1996) N. Eur. J. Med. Chem., 31, p. 915De Azevedo, M.B.M., Alderete, J.B., Lino, A.C.S., Loh, W., Faljoni-Alario, A., Durán, N., (2000) J. Incl. Phenom. Macrocyclic. Chem., 37, p. 67Zhou, D., Wu, Y., Xu, Q., Yang, L., Bai, C., (2000) Z. Tan. J. Incl. Phenom. Macrocyclic. Chem., 37, p. 273Ammar, H.O., Ghorab, M., El-Nahhas, S.A., Emara, I.H., Makram, T.S., (1999) Pharmazie, 54, p. 142Muñoz De La Pena, A., Ndou, T.T., Zung, J.B., Warner, I.M., (1991) J. Phys. Chem., 95, p. 3330Smith, V.K., Ndou, T.T., Warner, I.M., (1994) J. Phys. Chem., 98, p. 8627Blanco, M., Coello, J., Iturriaga, H., Maspoch, S., Pérez-Maseda, C., (2000) Anal. Chim. Acta, 407, p. 233Ohashi, M., Kasatani, K., Shinohara, H., Sato, H., (1990) J. Am. Chem. Soc., 112, p. 5824Harata, K., Uedaria, H., (1975) Bull. Chem. Soc. Jpn., 48, p. 375Schellman, J.A., (1968) Acc. Chem. Res., 1, p. 144Bettinetti, G.P., Gonzzaniga, A., Mura, P., Giordano, F., Setti, M., (1992) Drug Dev. Ind. Pharm., 18, p. 39Mura, P.P., Faucci, M.T., Parrini, P.L., Furlanetto, S., Pinzauti, S., (1999) Int. J. Pharm., 179, p. 117Cunha-Silva, L., Teixeira-Dias, J.J.C., (2002) J. Phys. Chem., 106, p. 3323Lai, S., Locci, E., Piras, A., Porcedda, S., Lai, A., Marangiu, B., (2003) Carbohydr. Res., 338, p. 222

On the stability of 2 \sqrt{2} x 2 \sqrt{2} oxygen ordered superstructures in YBa2Cu3O6+x

We have compared the ground-state energy of several observed or proposed " 2 \sqrt{2} x 2 \sqrt{2} oxygen (O) ordered superstructures " (from now on HS), with those of "chain superstructures" (CS) (in which the O atoms of the basal plane are ordered in chains), for different compositions x in YBa2Cu3O6+x. The model Hamiltonian contains i) the Madelung energy, ii) a term linear in the difference between Cu and O hole occupancies which controls charge transfer, and iii) covalency effects based on known results for $t-J$ models in one and two dimensions. The optimum distribution of charge is determined minimizing the total energy, and depends on two parameters which are determined from known results for x=1 and x=0.5. We obtain that on the O lean side, only CS are stable, while for x=7/8, a HS with regularly spaced O vacancies added to the x=1 structure is more stable than the corresponding CS for the same x. We find that the detailed positions of the atoms in the structure, and long-range Coulomb interactions, are crucial for the electronic structure, the mechanism of charge transfer, the stability of the different phases, and the possibility of phase separation.Comment: 24 text pages, Latex, one fig. included as ps file, to be publisheb in Phys. Rev.