celonae de 2010 - ub.edu · Daniel Navajas Navarro MEDICINA Ciències Fisiològiques Lara Ortas...

jornadaCol·le

gi Oficial de Metges de Barcelona

13 d’octubre de 2010

jornadaCol·le

gi Oficial de Metges de Barcelona

13 d’octubre de 2010

Book of aBstracts

Disseny gràfic i maquetació: Cristina Muñoz Idoate | www.idoate.com

3aBstracts

taula de

5Salutació del director

7Registre de participants

9Programa general

11Keynote speaker

13Abstracts

23Posters

continguts

5aBstracts

Benvolguts investigadors i investigadores,

Em plau presentar-vos aquest resum, que inclou les xerrades i pòsters que alguns de vosaltres ens vau oferir amb motiu de la III JORNADA IN2UB, celebrada el passat 13 d’octubre de 2010.

Un any més, vull agrair-vos a tots el vostre entusiasme a l’hora de parti-cipar a la jornada. En aquesta jornada en concret, vull agrair la participació de Rolf Möller, de la Universitat de Duisburg-Essen, una de les universitats membres de la xarxa IRUN, i de Ramon Alcubilla, de la UPC, com a testimoni de l’aliança entre aquesta universitat i la UB pel que fa al projecte Barcelona Knowledge Campus (BKC).

El meu agraïment també a Lluïsa Pérez i a Ramon Vicente pel seu suport en l’organització científica, i a les dues chairwomen de la JORNADA, Mª Lui-sa García i Francesca Peiró.

L’edició del recull ha anat a cura de Meritxell Salvany, gestora de l’institut, mentre que el disseny gràfic és de Cristina Muñoz idoate. Volem agrair-los a elles també la seva col.laboració, així com agraïm a Isabel Calaf i a Salvador Piqué, del Col•legi Oficial de Metges de Barcelona (COMB), la seva bona feina pel que fa a la logística de la jornada.

Recordeu que podeu consultar també aquest recull al web http://www.ub.edu/in2ub.

Esperem que la jornada hagi estat enriquidora per a tots vosaltres i que l’any vinent ens tornarem a trobar amb noves experiències i noves fites.

Amílcar LabartaDirector de l’IN2UB

Barcelona, desembre de 2010

6iii Jornada in2uB - 13 octubre 2010

llista de ParticiPantsNOM COGNOM 1 COGNOM 2

ALTRES OBSERVACIONS

FACULTAT DEPARTAMENT

Sergio Illera FÍSICA Electrònica

Ramon Alcubilla PONENT UPC

Anna Alemany Arias FÍSICA Fonamental

Rosa Ma. Aparicio Pelegrín FARMÀCIA Farm. i Tecnologia Farmac.

Hicham Bakkali FÍSICA Fonamental

Manuel Barranco FÍSICA ECM

Xavier Batlle Gelabert FÍSICA Fonamental

Valentino Bianco FÍSICA Fonamental

Edgar Julián Cabrera FÍSICA Aplicada i Òptica

Ana Cristina Calpena Campmany FARMÀCIA Farm. i Tecnologia Farmac.

Carla Carbonell Cortés FÍSICA Fonamental

Josep Claret QUÍMICA Química Física

Meritxell Cortés QUÍMICA Química Física

Immaculada Dinarès FARMÀCIA Farmacol. I Quím. Terap.

Oscar Domènech Cabrera FARMÀCIA Físicoquímica

M. Antonia Egea Gras FARMÀCIA Físicoquímica

Gustavo Egea Guri MEDICINA Biologia Cel·lular…

Elvira Escribano Ferrer FARMÀCIA Farm. i Tecnologia Farmac.

Marta Espina García FARMÀCIA Físicoquímica

Joan Estelrich Latràs FARMÀCIA Físicoquímica

Sonia Estradé FÍSICA Electrònica

Francisco Fernández Campos FARMÀCIA Farm. i Tecnologia Farmac.

Federico Ferrarese FÍSICA Electrònica

Ana Flo Sierra FARMÀCIA

Paloma Florez FARMÀCIA Farm. i Tecnologia Farmac.

Arantxa Fraile Rodríguez PONENT IN2 FÍSICA Fonamental

Xavier Garcia Capdevila QUÍMICA C. dels Mat. i Eng.Metal·lúrgica

Antoni Garcia Santiago FÍSICA Fonamental

Ma José García Celma PONENT IN2 FARMÀCIA Farm. i Tecnologia Farmac.

Núria García Castelló FÍSICA Electrònica

Marisa García López FARMÀCIA Fisicoquímica

Ma. Luisa Garduño Ramírez FARMÀCIA Convidada A. C. Calpena

Elisabet González Mira FARMÀCIA Fisicoquímica

Frank Güell FÍSICA Electrònica

Oriol Güell QUÍMICA Química Física

Jordi Hernández Borrell FARMÀCIA Fisicoquímica

Sergi Hernández Márquez FÍSICA Electrònica

Sergi Hernández Navarro QUÍMICA Química Física

Narcís Homs Martí PONENT IN2 QUÍMICA Química Inorgànica

7aBstracts

NOM COGNOM 1 COGNOM 2ALTRES OBSERVACIONS

FACULTAT DEPARTAMENT

Jordi Ignés Mullol QUÍMICA Química Física

Amílcar Labarta Rodríguez FÍSICA Fonamental

Jacinto Lauroba FARMÀCIA Farm. i Tecnologia Farmac.

Raquel Lázaro Cano FARMÀCIA

Julià López Vidrier FÍSICA Electrònica

Toni Luque Santolaria FÍSICA Fonamental

Carlos Martínez Boubeta PONENT IN2 FÍSICA Electrònica

Alexander Martínez Concepción FÍSICA Electrònica

Rolf Möller PONENT DUISBURG-ESSEN

M. Teresa Montero Barrientos FARMÀCIA Fisicoquímica

Miguel Morales QUÍMICA C. dels Mat. i Eng.Metal·lúrgica

Genoveva Morral Ruiz FARMÀCIA Farm. i Tecnologia Farmac.

Daniel Navajas Navarro MEDICINA Ciències Fisiològiques

Lara Ortas Pomer FARMÀCIA Farmacol. I Quím. Terap.

Francesca Peiró Martínez FÍSICA Electrònica

Paolo Pellegrino FÍSICA Electrònica

Oriol Penon Esteva FARMÀCIA Farmacol. I Quím. Terap.

M.Lluïsa Pérez Garcia FARMÀCIA Farmacol. I Quím. Terap.

Alba Pulido Companys PONENT IN2 QUÍMICA Química Física

Joan Manel Ramírez PONENT IN2 FÍSICA Electrònica

Joana Rangel De Araújo FARMÀCIA Fisicoquímica

José Manuel Rebled FÍSICA Electrònica

Mafalda Rodrigues FARMÀCIA Farmacol. I Quím. Terap.

Ferran Roig Roig FARMÀCIA Farm. i Tecnologia Farmac.

Albert Romano FÍSICA Electrònica

Francesc Sagués Mestre QUÍMICA Química Física

Meritxell Salvany Balada Gestora IN2

Lluis Sánchez Murillo FARMÀCIA Farmacol. I Quím. Terap.

Cristina Seco FÍSICA Fonamental

Mercè Segarra QUÍMICA C. dels Mat. i Eng.Metal·lúrgica

Javier Selva Sánchez PONENT IN2 MEDICINA Biologia Cel·lular…

Carme Suárez Germà FARMÀCIA Fisicoquímica

Elisa Vallés QUÍMICA Química Física

Oriol Valls Planells FARMÀCIA Fisicoquímica

Martha Vázquez FARMÀCIA

Saúl Vélez Centoral FÍSICA Fonamental

Anna Vilà Arbonés FÍSICA Electrònica

Elena Xuriguera QUÍMICA C. dels Mat. i Eng.Metal·lúrgica

9aBstracts

Programa9.20-9.50 Recepció i acollida.

9.50-10.00 Obertura: Amílcar Labarta.

10.00-10.50Rolf Möller (University of Duisburg-Essen)

10.50-11.20 Coffee break.

11.20-11.45 Ramon Alcubilla (UPC).

11.45-12.10 Mª José García Celma (UB)Development of Medicines in Nanostructured Surfactant Systems.

12.10-12.30 Javier Selva (UB)Silver Sub-nanoclusters Electrocatalyze Ethanol Oxidation and Provide Protection against Ethanol Toxicity in Cultured

Mammalian Cells.

12.30-12.50 Carlos Martínez-Boubeta (UB)Ferromagnetic Nanoparticles for Cancer Treatment: Invitro.Results and Monte Carlo Modelling. Influence of Dipolar Ineractions on Hyperthermia.

13.00 Lunch.

14.30-16.00 Poster Session.

16.00-16.20 Alba Pulido (UB)Two-dimensional Microfluidics on Circuits of Wettability Contrast.

16.20-16.40 Joan Manel Ramírez (UB)Realization of Efficient LED’s Emitting at 1.55 μm.

16.40-17.00 Arantxa Fraile Rodríguez (UB)Probing Single Magnetic Nanoparticles by X-ray

Spectromicroscopy.

17.00-17.25 Narcís Homs (UB)The Development of Tailored Co-based Catalysts for Reformation Processes of Biofuels to Hydrogen.


keynote sPeakers

11aBstracts

Prof. rolf moller University of Duisburg-EssenExpert in surface science. He obtained his PhD in Physics in 1986 in the University of Freiburg. Then, he went for several post-doc positions. In particu-lar, he stayed for a year in the IBM Laboratory in Switzerland. From 1997 to present, he has been the Chair of the Surface Science Group at the Phy-sics Faculty of the University of Duisburg-Essen. His group takes also part in the Center for Nano-integration, a nanotechnology center founded for the University of Duisburg in 2005 to promote the research in this field. The areas of interest of Pro-fessor Moller are:i) Analysis of organic monolayers on metallic, semi conducting and insulating surfaces; ii) Elementary processes of friction and energy dis-sipation; andiii) Electronic transport at the nanoscale.

Prof. ramon alcubilla CRNE, Universitat Politècnica de Catalunya (UPC), offe-red also a talk at the III Jornada IN2UB.

aBstracts


The development of tailored co-based catalysts for reformation processes of biofuels to hydrogen

NARcíS HomS and PilAR RAmiREz DE lA PiSciNACatalytic Materials Group, MATCAT,Dpt. Química Inorgànica and Institut de Nanociència i Nanotecnologia, Universitat de Barcelona, Spain

This talk presents the use of hydrogen in an energy con-text by means of its application as an energy carrier in fuel cell systems. We will revise the current production of H2 and then we will afford the reformation processes of bio-alcohols as an alternative route for the H2 production.Although H2 is the most abundant element in the Uni-verse, on the Earth is only combined mainly forming part of water, biomass and fossil hydrocarbons. Nowadays H2 is mainly produced from fossil fuels. The use of H2 as an energy carrier will not be accomplished if new produc-tion methods are not developed or other sources applied. One approach is to use the well-known reformation tech-nology to biomass-derived sources. These are for exam-ple bio-alcohols which are now currently used as alter-native fuels and produced in large amounts worldwide. The reformation of ethanol is of main interest. However, although the yield of hydrogen is high, the ethanol steam-reforming is an endothermic process. It is possible do a combination of the steam-reforming process with the partial oxidation process which is exothermic. Thus it can be achieved an appropriate energy balance and the hydrogen yield may be adjusted. A higher oxygen/etha-nol ratio produce a more favourable energy balance but a lower number of H2 mole obtained per mol of ethanol reacted.

Moreover, a general problem of catalytic processes is the deactivation of catalysts and the oxygen introduction may produce a diminution of the carbon deposits on the catalyst and consequently a lower catalyst deactivation

and a higher lifetime of the catalysts. The development of efficient catalysts for such processes is of current in-terest and we present our research achievements on the subject.

As a conclusion, we demonstrate that the use of bio-al-cohols as bio-ethanol and glycerol may be an alternative route to produce H2 which could be used to feed fuel cell devices.

15aBstracts

Ferromagnetic Nanoparticles for Cancer treatment: in-vitro results and monte carlo modelingInfluence of dipolar interactions on hyperthermia

D. SERANtES (1), D. BAlDomiR (1), c. mARtiNEz-BoUBEtA (2), A. cHAlKiDoU (3), K. SimEoNiDiS (3), m. ANgElAKERiS (3), tH. SAmARAS (3), o. KAlogiRoU (3), K. PAPAziSiS (4), c. DENDRiNoU-SAmARA (5), ll. BAlcEllS (6), and B. mARtíNEz (6)(1) Inst. Invest. Tecnolóxicas, and Departamento de Física Aplicada, USC,15782 Santiago de Compostela, Spain(2) IN2UB and Departament d’Electrònica, Universitat de Barcelona, 08028 Barcelona, Spain(3) Department. of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece(4) Molecular Oncology Laboratory, Theagenio Cancer Hospital, 54 007 Thessaloniki, Greece(5) Department of Chemistry, Aristotle University of Thessaloniki, 54 124 Thessaloniki, Greece(6) ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain

We are introducing an alternative way for synthesizing high quality metallic, soft ferromagnetic Fe nanoparti-cles (NPs) with an outer protective MgO sheath, by us-ing one-step vapour-phase condensation.(1) Research on MgO was originally motivated because Mg2+ ions exhibit a biological activity for bone regeneration and it is ubiq-uitous and essential to all living organism. Accordingly, it was shown that the particles satisfy a few of technical requirements for the practical use in real clinics, such as a high biocompatibility in living cells in-vitro, an injection through blood vessels without any clothing problems in murine model, the potential to be used as contrast agent in the field of diagnostic MRI, and a high absorption rate (SAR) for therapeutic hyperthermia at small particle con-centration.

In this report we show both experimental evidences and Monte Carlo modeling of the effects of interparticle dipo-lar interactions on the hysteresis losses. In-vitro experi-ments were performed in three different (MDA, SkBr3 and MCF7) human breast cancer cell lines in order to assess cytotoxicity, iron uptake and heating effectiveness. The physical model employed for our numerical simulations is the same as in Ref. (2). Results indicate that an increase of the intensity of dipolar interactions produce a decrease in the magnetic susceptibility and hysteresis losses, thus diminishing the hyperthermia output (Figure). These find-ings may have important clinical implications for cancer treatment.

(1) C. Martinez-Boubeta et al. “Self-assembled multifunctional Fe/MgO nanospheres for magnetic resonance imaging and hyper-thermia”, Nanomed.: Nano. Bio. Med. 6, 362 (2010).

(2) J. García-Otero, M. Porto, J. Rivas, A. Bunde, “Influence of Dipolar Interaction on Magnetic Properties of Ultrafine Ferromagnetic Particles”, Phys. Rev. Lett. 84, 167 (2000).

Figure: Field-dependence of the SAR for different concentrations (c= 0.007, 0.070, 0.150). Field data is also expressed in real units (Ha= 2K/MS) in order to make easier the comparison with the experimental values for spherical particles (75 nm) with a ferromag-netic behavior well above room temperature, being the effective anisotropy constant (K ≈ 4.5 × 104 J/m3) and saturation magnetization (MS ≈ 210 emu/g).


Probing single magnetic nanoparticles by x-ray spectromicroscopy

A. FRAilE RoDRígUEz (1,2), A. KlEiBERt (1), J. BANSmANN (3), l. J. HEyDERmAN (1) and F. NoltiNg (1)(1) Paul Scherrer Institut, Villigen PSI, Switzerland (2) Departament de Física Fonamental and IN2UB, Universitat de Barcelona, Barcelona, Spain(3) Department of Surface Chemistry and Catalysis, University of Ulm, Ulm, Germany

Magnetic nanoparticles exhibit a variety of unusual phe-nomena when compared to the bulk materials, particu-larly when the dimensions involved are comparable to critical magnetic length scales such as the exchange length(1,2). An open challenge is to build a consistent pic-ture of the single-domain limit and of the particle size dependence of the spin arrangement close to the single- to multi-domain transition. A detailed analysis of such size-dependent transitions is difficult in magnetic meas-urements encompassing large particle ensembles since single-particle properties are masked by distributions of particle size, anisotropies and dissimilar local interac-tions with the underlying substrate.

In this work we combine x-ray magnetic circular dichr-oism (XMCD) with photoemission electron microscopy (PEEM) to study the magnetization orientation of single iron (Fe) particles with sizes ranging from 5 to 25 nm. We show that above a critical size of ~6 nm, the competition

of exchange interaction and anisotropy energy can lead to the formation of noncollinear spin structures in Fe na-noparticles coupled to a ferromagnetic cobalt substrate, while the magnetization of the smaller particles is aligned collinearly with that of the substrate(3). This transition can only be captured by quantitatively determining the mag-netization orientation of individual nanoparticles. Numer-ical calculations indicate a sharp transition from an ex-change-dominated to an anisotropy-dominated regime: the smaller particles are in a single-domain state with magnetization collinearly aligned to that of the substrate, while larger particles exhibit a static spin spiral analo-gous to an exchange spring(3). Our results demonstrate that unexpected spin arrangements at nanoscale inter-faces can result from the balance between the particle-substrate interaction and the individual properties of the particles. This knowledge is crucial for the development of novel devices which make use of nanoscale magnetic phenomena at interfaces.

(1) J. Bansmann et al., “Magnetic and structural properties of isolated and assembled clusters”, Surf. Sci. Rep. 56, 189, (2005).

(2) X. Batlle and A. Labarta, “Finite-size effects in fine particles: magnetic and transport properties”, J. Phys. D, 35, R15 (2002).

(3) A. Fraile Rodríguez, A. Kleibert, J. Bansmann, A. Voitkans, L. J. Heyderman, and F. Nolting, “Size-dependent spin structures in iron nanoparticles”, Phys. Rev. Lett., 104, 127201 (2010).

17aBstracts

Realization of efficient LED’s emitting at 1,55 µm

J.m RAmíREz, o. JAmBoiS, D. NAvARRo, S. HERNáNDEz, y. BERENcéN, F. FERRARESE, A. mARtíNEz, P. PEllEgRiNo and B. gARRiDo Departament d’Electrònica, IN2UB, Universitat de Barcelona, Spain

One of the key challenges of Si photonics is the realiza-tion of an efficient Si-based light source. Silicon quantum dots (nanocrystals) embedded in amorphous silica ma-trices has been shown as promising material to achieve this goal. Due to quantum confinement, the radiative re-combination as well as an enlargement of the band gap in Si is observed, allowing the emission in the visible range. Moreover, it has been demonstrated that silicon nanoc-rystals act as efficient sensitizers for Erbium lumines-cence in silicon rich silicon oxide layers.(1) The enhanced luminescence at 1.55 µm is particularly interesting as it corresponds to the 3rd window of telecommunications.This work deals with the excitation mechanisms and the optimization of the electroluminescence (EL) of such systems. For this, several materials were investigated.

Two deposition techniques were used (plasma enhanced chemical vapour deposition, and low pressure chemi-cal vapor deposition) to fabricate Er-doped Silicon rich silicon oxide. The silicon nanocrystals were formed after deposition by annealing the layers at high temperature (2). The silicon excess was changed from 12%, up to 20%. MOS capacitors were used to study the electrical trans-port and the electroluminescence.Power efficiencies from 1E-5 to 2E-2% were achieved in DC excitation. The emission of these devices has been increased by the optimization of the stress voltage conditions. Working in AC mode and varying the frequency, the duty cycle and voltage of the input signal, improvement on this LED’s emission has been observed.

(1) AJ Kenyon,” Evidence of energy coupling between Si nanocrystals and Er3+ in ion-implanted silica thin films”, Applied Physics, 75 (1999)

(2) O. Jambois, ” Towards population inversion of electrically pumped Er ions sensitized by Si nanoclusters”, Optics Express, Vol. 18 Issue 3, pp.2230-2235 (2010)

Figure 1: Evolution of the EL with frequency at the visible range.

Figure 2: El from the erbium at 1,55 mm.


development of medicines in nanostructured surfactant systems

m.J. gARcíA cElmADepartment of Pharmacy and Pharmaceutical Technology. Faculty of Pharmacy. University of Barcelona.R+D Associated Unit to CSIC.Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN).

The design and development of new delivery systems to enhance the effectiveness of existing drugs and new bio-logical molecules have an important role in pharmaceuti-cal research. Delivering a drug precisely and safely to its target site at the right period of time to have a controlled release and achieve the maximum therapeutic effect re-mains a yardstick in the design and development of novel drug delivery systems. Nanocarriers have the possibility of providing endless opportunities in the area of drug de-livery and therefore are increasingly being investigated to harness their potential. Nanocarriers, on account of their higher ratio of surface area to volume, show improved pharmacokinetics and biodistribution of therapeutic agents and thus minimize toxicity by their preferential ac-cumulation at the target site. They can improve solubility of hydrophobic compounds and render them suitable for parenteral administration. Furthermore, they increase the stability of a variety of therapeutic agents, like peptides and oligonucleotides.

Surfactant systems appears in nanotechnological litera-ture and patents as solubilisation and reaction media and they have potential applications as colloidal nanocarri-

ers for targeted drug delivery. In this presentation, the re-search activity of the group “Development of medicines in nanostructured surfactant systems” in the Faculty of Pharmacy will be presented. This research has been carried out in collaboration with the QCI/CSIC group, in the frame of CIBER-BBN. Among the nanostructured surfactant systems designed, the results obtained with microemulsions, nano-emulsions, highly concentrated emulsions, polymeric nanoparticles and meso/macropo-rous materials will be emphasized. Formation of nano-emulsions and highly concentrated emulsions can be achieved by low energy methods (1,2). One of the most interesting applications of these systems is their use as reaction media. Polymerization in the continuous and/or dispersed phase leads to highly porous materials such as solid foams or to nanoparticles. The structure obtained can be controlled by composition parameters and the size and polidispersity of the materials obtained are dependent of the emulsion droplet size distribution and thus on the emulsification method2. Several drugs have been incorporated to the nanostructured surfactant systems developed and drug release kinetics have been determined (3,4).

(1) N. Sadurní, C. Solans, N. Azemar, M.J. García-Celma, “Studies on the formation of O/W nano-emulsions, by low-energy emulsification methods, suitable for pharmaceutical applications”. European Journal of Pharmaceutical Sciences 26, 438-445 (2005).

(2) J. Esquena, G.S.R. Ravi Sankar, C. Solans, “Highly concentrated W/O emulsions prepared by the PIT method as templates for solid foams” Langmuir 19, 2983-2988 (2003)

(3) P. Izquierdo, J.W. Wiechers, E. Escribano, M.J. García-Celma, T.F. Tadros, J. Esquena, J.C. Dederen, C. Solans, “A study on the influence of emulsion droplet size on the skin penetration of tetracaine”. Skin Pharmacology and Physiology 20, 263-270 (2007).

(4) G. Calderó, M. Llinàs, M.J. García-Celma, C. Solans, “Studies on controlled release of hydrophilic drugs from W/O high internal phase ratio emulsions”. Journal of Pharmaceutical Sciences 99 (2), 701-711 (2010).

19aBstracts

Two dimensional microfluidics on circuits of wettability contrast

AlBA PUliDo-comPANyS, PAtRiciA BURRiEl, JoRDi igNéS-mUllol, JoSEP clAREt, and FRANcESc SAgUéSSOC and SAM group, Universitat de Barcelona, Departament de Química Física. Barcelona, Spain.

Inspired by the devices and achievements in the field of microfluidics, we present an experimental set-up that al-lows to control the flow of Langmuir monolayers through a circuit imprinted on a solid suport. The circuits are pre-pared on top of a brass plate, and consist on hydrophilic tracks embedded in a superhydrophobic surface (Fig. A). An electroless silver deposit turns the surface hydrophilic. A predesigned circuit pattern is imprinted during a soft litography process, and a self assembled monolayer (SAM) of a fluorinated thiol turns the surface surrounding the circuit track superhydrophobic (contact angle 170º). The brass plate is mounted into a three-compartments Langmuir trough, and in each compartment a hydrophilic barrier and a Wilhelmy plate balance allow the control of monolayer flow and surface pressure. As an application of this device, we have measured the diffusion coefficient of a fluorescent probe dispersed in a DMPC monolayer coflowing with a pure DMPC monolayer through a rec-tilinear path on a water subphase (Fig. B).(1) As future developments it is planned to look for different mobility-mediated phenomena for species dispersed in monolay-ers, such as sorting, mixing or chemical reactions along the contact line, using a rectilinear as well as serpentine paths.

(1) P. Burriel, J. Ignés-Mullol, J. Claret, F. Sagués, “A two dimensional microfluidic device using circuits of wettability contrast “, Langmuir 26 (7), 4613-4615 (2010).

Figure A: Rectilinear circuit and picture of a water droplet on top of the superhydrophobic surface.

Figure B: Coflow of a monolayer

containing a fluorescent probe and a pure DMPC

monolayer through a rectilinear path.


development of medicines in nanostructured surfactant systems

JAviER SElvA(1), SUSANA E. mARtíNEz(1), DAviD BUcEtA(2), mARíA J. RoDRígUEz-vázqUEz(2), m. cARmEN BlANco(2), m. ARtURo lóPEz-qUiNtElA(2) and gUStAvo EgEA(1)(1) Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Instituts d’Investigacions Biomè-diques August Pi i Sunyer (IDIBAPS) i de Nanociències i Nanotecnologia (IN2UB), Universitat de Barcelona, E-08036 Barcelona, Spain(2) Laboratorio de Magnetismo y Nanotecnología (Nanomag), Instituto de Investigación Tecnológica, Universidad de San-tiago de Compostela, E-15782 Santiago de Compostela, Spain. [email protected]

Silver atomic quantum clusters (AgAQCs), with two or three silver atoms, show electrocatalytic activities that are not found in nanoparticles or in bulk silver. AgAQCs supported on glassy carbon electrodes oxidize ethanol and other alcohols in macroscopic electrochemical cells in acidic and basic media. This electrocatalysis occurs at very low potentials (from ~ +200 mV vs RHE), at physi-ological pH, and at ethanol concentrations that are found in alcoholic patients. When mammalian cells are co-ex-posed to ethanol and AgAQCs, alcohol-induced altera-tions such as rounded cell morphology, disorganization of the actin cytoskeleton, and activation of caspase-3 are all prevented. This cytoprotective effect of AgAQCs

is also observed in primary cultures of newborn rat as-trocytes exposed to ethanol, which is a cellular model of fetal alcohol syndrome. AgAQCs oxidize ethanol from the culture medium only when ethanol and AgAQCs are added to cells simultaneously, which suggests that cyto-protection by AgAQCs is provided by the ethanol electro-oxidation meditated by the combined action of AgAQCs and cells. Overall, these findings not only show that AgAQCs are efficient electrocatalysts at physiological pH and prevent ethanol toxicity in cultured mammalian cells, but also suggest that AgAQCs could be used to modify redox reactions and in this way promote or inhibit bio-logical reactions.

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Cluster analysis approach to the phase transition of water in supercooled region

vAlENtiNo BiANco and giANcARlo FRANzESEDepartament de Física Fonamental, Universitat de Barcelona

Water is a fundamental substance for all processes in-volving life. It has many unusual properties compared with other liquids. Recent studies of hydrated biomole-cules and nanoconfined water suggest that, surprisingly, the anomalous properties of water are consistent with the hypothesis of the occurrence of first-order phase-transition between two liquids with diferent densities at low temperature and high pressure. In this hypothesis the phase transition line ends in a liquid-liquid critical point.To validate this hypothesis experiments in nanoconfine-

ment could be very valuable, because the yallow to ex-plore the water behavior in a region of temperature that would be other wise inaccessible for bulk liquid water, as a consequence of inevitable crystallization.

We present here a coarse-grained model of water that give insight in to the physics of a nanoconfined water monolayer. Our model allows us to analyze the possible existence of a critical point thanks to a mapping into a percolating model.

ReferencesK.Stokely, M.G.Mazza, H.E.Stanley, G.Franzese, Proc.Natl.Acad.Sci.U.S.A.107,1301-1306(2010).

G.Franzese, F.delosSantos, J.Phys.:Cond.Matt. 21504107 (2009).

M.G.Mazza, K.Stokely,E.G.Strekalova,H.E.Stanley, G.Franzese, ComputerPhys.Comunications180, 497-502(2009).

P.Kumar, G.Franzese and H.E.Stanley, Phys.Rev.Lett.100,105701 (2008).

G.Franzese, H.Stanley, J.Phys.:Cond.Matt.19, 205126 (2007).


uniform large area colloidal self-assembled layers of silica submicron-particles by langmuir-blodgett technique

EDgAR JUliáN cABRERA, SABiNE PoRtAl and ENRic BERtRANFEMAN Group, Department of Applied Physics and OpticsInstitute Nanoscience and Nanotechnology, IN2UB, University of Barcelona.

Large areas nanopatterned surfaces have a raising inter-est in the fabrication of templates and thin membranes, biomedical sensors and for the next-generation photonic devices. Morphological and structural properties of two-dimensional (2D) photonic crystal monolayers made up of silica particles. The silica submicron-particles of 230 nm diameter were produced by Stober sol-gel process with morphological, structural and very low size disper-sion characteristics suitable to self-assemble them in closed-packed 2D crystal monolayers. Langmuir–Blodg-ett technique was used to deposit the nanometric silica particles on c-Si substrates. The resulting films consist-ed of a single monolayer of submicrometric particles ar-ranged in a hexagonal compact structure. The monolayer

building characteristics of the particles were controlled by monitoring the surface pressure vs. surface area (Π-A) isotherm during the deposition process. Large area ar-rangement of the particles becomes critically depending of particles (low size dispersion and spherical shape), hence an accurate choice of submicron-particles is a key point to achieve it. The shape of the particles and the film structure and morphology were characterized by environmental scanning electron microscopy. Finally, the wettability of the monolayer was studied using the sessile drop method. The resulting monolayers show an arrangement extended to large areas in a close-packed structure.

45Posters

Combination of Electron Tomography and Electron Beam Precession applied to Sn precipitates in Al matrix

Jm. REBlED (1,2), ll. yEDRA (1), J. PoRtillo (3), S. EStRADé (1,3) and F. PEiRó (1)(1) LENS-MIND/IN2UB, Dept. d’Electrònica, Universitat de Barcelona, c/ Martí Franqués 1, 08028 Barcelona, CAT, Spain(2) Institut de Ciència de Materials de Barcelona, CSIC, 08193 Bellaterra, Catalonia, Spain(3) TEM-MAT, Serveis Cientificotècnics, Universitat de Barcelona, 08028, Barcelona, CAT, Spain

In nanoscience and nanotechnology, object size, shape and faceting are key features determining final function-ality and behavior of the investigated nanomaterial, just as well its specific composition.

Tomography is a powerful tool to obtain 3D information from 2D projection images. In particular, tomography is an active field in materials science, where the possibility to combine both the scanning approach and high angle annular dark field detectors (STEM- HAADF Tomography) allows the acquisition of 2D images which display con-trast variations due to atomic number in the object, and avoid the artifactual changes which appear while tilting the object due to diffraction contrast seen in conven-tional TEM (non-STEM) illumination.(1) More recently, new expectatives have been opened with the combination of tomography with electron diffraction (2,3,4) and electron precession5 in the field of electron crystallography.

In the present work we will combine the bright field im-aging mode in TEM with both electron tomography and electron beam precession techniques in order to recon-struct the morphology of Sn precipitates embedded in a Al matrix. The tilt series was acquired in a range from +49º to -61º at intervals of 2º and with a precession angle of 0.6º. Our preliminary results clearly show the advan-tage of the precession technique to avoid the presence of artifacts due to diffraction and curvature contrast in the images (figure 1). As a drawback, we should remark that the images obtained with the precession system ac-tivated present a slightly blurred aspect due to the limita-tions in achieving optimum focusing conditions with our present instrumentation. Despite this, the images ena-bled to carry out a 3D reconstruction of the object.

(1) P. A. Midgley et al., Journal of Microscopy, 223 (2006) 185(2) U. Kolb et al., Acta Crystallographyca, A63 (2007) s66(3) U. Kolb et al., Ultramicroscopy, 107 (2007) 507(4) U. Kolb et al., Ultramicroscopy, 108 (2008) 763(5) E. Mugnaioli et al., Ultramicroscopy, 109 (2009) 758

FIG. 1. Selected bright field images of a Sn precipitate into the Al matrix acquired at different angles without (a-d) and with precession (e-h), respectively, in conventional TEM mode.


Magnetic deflagration in Gd5ge4

S. vélEz (1), J. m. HERNàNDEz (1), A.FERNáNDEz (1), F. mAcià (1), c. mAgEN (2), P. AlgARABEl (3), J. tEJADA (1), and E.m. cHUDNovSKy (1,4)(1) Facultat de Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain(2) Instituto de Nanociencia de Aragón-ARAID, Universidad de Zaragoza, 50009 Zaragoza, Spain(3) Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, Universidad de Zaragoza and Consejo Superior de Investigaciones Científicas, 50009 Zaragoza, Spain(4) Physics Department, Lehman College, The City University of New York, 250 Bedford Park Boulevard West,Bronx, New York 10468-1589, USA

The field-induced the AFMFM magnetostructural tran-sition in the intermetallic compound Gd5Ge4 occurs, in certain conditions, in an avalanche-like manner (Fig. 1). In this work we have studied, using a large polycrystalline sample, whether the magnetic deflagration is responsible for the avalanches observed. The spontaneous appear-ance and the magnetic dynamics of these avalanches have been studied with different experimental techniques and under different conditions. We show that all the data

obtained fit well into the theoretical framework of mag-netic deflagration1 with a speed of the flame in the range of 0.1-1.0 m/s (Fig. 2). This adds Gd5Ge4 to the growing family of materials (that now includes molecular magnets (2,3) and manganites(4) which exhibit this phenomenon. The novelty of the magnetic deflagration in Gd5Ge4

(5) is that the burning of the metaestable magnetic phase involves a magnetostructural transition alongside with the re-or-dering of spins.

Figure 2: Ignition field dependence of the avalanche speed in the Gd5Ge4 sample for two different initial states (ZFC and FC at 10KOe). Avalanches were ignited at T=2 K. The inset shows the maximum measured temperature for each avalanche.

Figure 1: Isothermal (T = 2 K) magnetization curves of the Gd5Ge4 sample cooled in the presence of the magnetic field, HFC. At low HFC, when the initial state is mostly AFM, the magnetization changes in an avalanche-like process. Avalanches occur only at low temperatures and high-field-sweep rates. The inset shows the initial magnetization vs field, achieved in a FC process.

(1) D. A. Garanin and E. M. Chudnovsky, Phys. Rev. B 76, 054410 (2007).

(2) Y. Suzuki, M. P. Sarachik, E. M. Chudnovsky, S. McHugh, R. Gonzalez-Rubio, N. Avraham, Y. Myasoedov, E. Zeldov, H. Shtrikman, N. E.

Chakov, and G. Christou, Phys. Rev. Lett. 95, 147201 (2005).

(3) A. Hernández-Mínguez, J. M. Hernandez, F. Macià, A. García- Santiago, J. Tejada, and P. V. Santos, Phys. Rev. Lett. 95, 217205 (2005).

(4) F. Macià, A. Hernández-Mínguez, G. Abril, J. M. Hernandez, A. García-Santiago, J. Tejada, F. Parisi, and P. V. Santos, Phys. Rev. B 76, 174424

(2007).

(5) S. Velez, J. M. Hernandez, A. Fernandez, F. Macià, C. Magen, P. Algarabel, J. Tejada, and E. M. Chudnovsky, Phys. Rev. B 81, 064437 (2010).

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