La Biomedicina del segle XXI

En els darrers trenta anys, la nostra societat ha assistit perplexa al desenvolupament d'una revolució que, sens dubte, la història jutjarà com la de més transcendència des que els humans habiten el planeta Terra. Ens referim a l'immens progrés en el coneixement de la ciència i la tècnica i al desenvolupament de les seves aplicacions. La biologia i, en particular, el desenvolupament de la biologia molecular, ocupa un espai majoritari en aquest procés. També la informàtica, l'electrònica, la robòtica o, de manera més general, la física i la química, estan en la primera línia de la seva evolució. Aquest capítol pretén posar totes aquestes troballes juntes en benefici de la nova medicina que ha sorgit d'aquesta barreja. Sense cap pretensió de voler resumir tots els avenços que componen aquesta nova medicina, hem volgut discutir breument el que signifiquen ara mateix i en un futur molt proper aquests canvis que comporten, entre molts altres, el diagnòstic i tractament millors del càncer, la teràpia gènica per a malalties genètiques fins ara incurables, els diferents tipus de diagnòstic per imatge amb un sofisticat suport informàtic, el coneixement del nostre genoma, la producció de proteïnes de propietats terapèutiques per biotecnologia, així com la connexió dels malalts a una xarxa de metges i d'hospitals que els permeti estar adequadament atesos. Nogensmenys, aquestes millores espectaculars d'un món altament tecnificat no ens han de fer ignorar els desafiaments ètics que tot això pot comportar, així com quelcom més elemental i bàsic, que és la solidaritat i caritat envers els febles, oblidats o mancats de recursos.In the last 30 years, we have assisted astonished to the development of a revolution that, with no doubt, history will judge as the most important since humans live in this planet. We refer to the progress in the knowledge of science and technology, and to the development of their applications. Biology, and, in particular, the development of molecular biology, is fundamental in this process. Also computer science, electronics, robotics, or, in a more general way, physics and chemistry are also in the frontline of their growth. This chapter only pretends to put together all these findings in favor of a new medicine. This is not an exhaustive review of these major advances, but just a brief summary of few breakthroughs like the improved diagnosis and treatment of cancer, gene therapy as a solution for genetic diseases, improved image based diagnosis methods, unravelling of the human genome, production of therapeutic recombinant proteins by biotechnology, as well as the new medical care system by having patients connected to physician and hospital networks. Nevertheless, those spectacular improvements in a highly technified world cannot avoid the new ethic challenges emerging in this process. At the same time, solidarity towards weak, poor and discriminated people does not have to be forgotten

The f-electron challenge: localized and itinerant states in lanthanide oxides united by GW@LDA+U

Many-body perturbation theory in the GW approach is applied to lanthanide oxides, using the local-density approximation plus a Hubbard U correction (LDA+U) as the starting point. Good agreement between the G0W0 density of states and experimental spectra is observed for CeO2 and Ce2O3. Unlike the LDA+U method G0W0 exhibits only a weak dependence on U in a physically meaningful range of U values. For the whole lanthanide sesquioxide (Ln2O3) series G0W0@LDA+U reproduces the main features found for the optical experimental band gaps. The relative positions of the occupied and unoccupied f-states predicted by G0W0 confirm the experimental conjecture derived from phenomenological arguments.Comment: 4 pages including 3 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

Asymptotic entanglement in a two-dimensional quantum walk

The evolution operator of a discrete-time quantum walk involves a conditional shift in position space which entangles the coin and position degrees of freedom of the walker. After several steps, the coin-position entanglement (CPE) converges to a well defined value which depends on the initial state. In this work we provide an analytical method which allows for the exact calculation of the asymptotic reduced density operator and the corresponding CPE for a discrete-time quantum walk on a two-dimensional lattice. We use the von Neumann entropy of the reduced density operator as an entanglement measure. The method is applied to the case of a Hadamard walk for which the dependence of the resulting CPE on initial conditions is obtained. Initial states leading to maximum or minimum CPE are identified and the relation between the coin or position entanglement present in the initial state of the walker and the final level of CPE is discussed. The CPE obtained from separable initial states satisfies an additivity property in terms of CPE of the corresponding one-dimensional cases. Non-local initial conditions are also considered and we find that the extreme case of an initial uniform position distribution leads to the largest CPE variation.Comment: Major revision. Improved structure. Theoretical results are now separated from specific examples. Most figures have been replaced by new versions. The paper is now significantly reduced in size: 11 pages, 7 figure

Negative Hall coefficient of ultrathin niobium in Si/Nb/Si trilayers

International audienceStructural and transport properties of thin Nb layers in Si/Nb/Si trilayers with Nb layer thickness d from 1.1 nm to 50 nm have been studied. With decreasing thickness, the structure of the Nb layer changes from polycrystalline to amorphous at d 3.3 nm, while the superconducting temperature T c monotonically decreases. The Hall coefficient varies with d systematically but changes sign into negative in ultrathin films with d < 1.6 nm. The influence of boundary scattering on the relaxation rate of carriers, and band broadening in the amorphous films, may contribute to this effect

Control of Dynamical Localization

Control over the quantum dynamics of chaotic kicked rotor systems is demonstrated. Specifically, control over a number of quantum coherent phenomena is achieved by a simple modification of the kicking field. These include the enhancement of the dynamical localization length, the introduction of classical anomalous diffusion assisted control for systems far from the semiclassical regime, and the observation of a variety of strongly nonexponential lineshapes for dynamical localization. The results provide excellent examples of controlled quantum dynamics in a system that is classically chaotic and offer new opportunities to explore quantum fluctuations and correlations in quantum chaos.Comment: 9 pages, 7 figures, to appear in Physical Review

La rendición de Menorca : un análisis de prensa /

Departament responsable de la tesi: Departament de Periodisme i de Ciències de la ComunicacióDurante la guerra civil española (1936-1939), la isla de Menorca fue la última en caer en manos franquistas del conjunto de las islas Baleares, el resto de las cuales llevaba más de 2 años en poder de los sublevados. Su posición geoestratégica y los hechos acaecidos desde el golpe de estado de 1936 generaron una intensa actividad diplomática y de espionaje de todas las potencias europeas que después acabarían combatiendo en la 2a Guerra Mundial. Los medios no escapan a estos efectos, reflejando tanto en sus coberturas como en las limitaciones de estas su posición delante de este evento, especialmente los medios editados en el estado español, donde se situaba el epicentro del conflicto. Por ello, se aplica un análisis de contenido a la cobertura de medios republicanos, franquistas e internacionales, con el objetivo de inferir la relación entre la información brindada por los medios y los hechos verificables de este episodio histórico, para el cual se desarrolla un marco específico. En esencia, buscamos profundizar en un episodio histórico relativamente desconocido en el conjunto de la guerra civil española pero con una gran importancia por los recursos y países implicados en la situación que se desenvolvía en la isla, cuyas acciones podían desencadenar en cualquier momento una guerra mundial que todos los implicados querían retrasar hasta estar preparados militarmenteDuring the Spanish Civil War (1936-1939), the island of Menorca was the last to fall into the insurgent hands of the Balearic Islands, the rest of which, had fallen 2 years ago. Its geostrategic position and the events since the coup of 1936 generated a intense diplomatic and intelligence activity of all the European powers that would end fighting after in the II World War. Media don't escape from these effects, reflecting at this coverage and limitations of these, their position at this event, especially the media published in the Spanish state, the epicenter of the conflict. Therefore, a content analysis is applied to cover loyalty, insurgent and international media in order to infer the relationship between the information provided by the media and verifiable facts of this historical episode, for which a framework is developed specific. In essence, we seek to deepen a relatively unknown historical episode in the whole of the Spanish civil war, but with great importance based of the resources and countries involved in the island situation, whose actions could trigger at any time a world war that everyone involved are interesting to delay to be prepared militarily

ETV5 i RUNX1, nous factors de transcripció implicats en la invasió miometrial del carcinoma endometrial

Actualment, en càncer d'endometri, està àmpliament acceptat el model dualístic que, atenent a bases morfològiques, diferencia tumors de tipus i o endometrioides dels de tipus ii o no endometrioides. La genètica molecular ha aportat dades que donen suport a aquest model dualístic de la tumorigènesi endometrial i algunes claus per a poder especular sobre la seqüència temporal de les alteracions moleculars que defineixen les rutes tumorigèniques. En els càncers endometrials endometrioides, o de tipus i, es coneixen alteracions majors, com poden ser el silenciament del gen PTEN, la inestabilitat de microsatèll. its associada a defectes en els gens reparadors de DNA, o mutacions al gen K-ras. Aquestes alteracions defineixen la progressió de l'endometri normal cap a la hiperplàsia i posteriorment cap al carcinoma. Recentment, l'ús de la tecnologia de microxips de cDNA per a identificar les diferències en els patrons d'expressió gènica entre els diferents tipus histològics de càncer d'endometri han permès la identificació de gens expressats diferencialment que podrien ajudar-nos a entendre les diferències en la biologia i el pronòstic clínic dels diferents histiotips tumorals. En el nostre laboratori hem aïllat i caracteritzat dos nous factors de transcripció, ETV5 i RUNX1, que estan associats amb els passos inicials de la infiltració miometrial en el càncer d'endometri endometrioide. Aquests estudis, i els d'altres gens implicats en el control de la mitosi com a mecanisme major de carcinogènesi en els càncers d'endometri no endometrioides, representen exemples de la utilitat dels estudis genètics amplis per a comprendre el procés de tumorigènesi i les rutes implicades en la patogènesi molecular del càncer d'endometri.A dualistic model, which has been established on a morphological basis and that differentiates type i endometrioid from type ii non-endometrioid endometrial cancer, is widely accepted. Molecular genetics have provided us with data supporting the dualistic model of endometrial tumorigenesis and with some clues to speculate about the sequence of the molecular alterations defining the tumorigenesis pathways. In type i endometrioid endometrial cancer, PTEN gene silencing, microsatellite instability associated with defects in DNA mismatch repair genes, or mutations in the K-ras gene are the known major alterations defining the progression from normal endometrium to hyperplasia and then on to carcinoma. Recently, cDNA microarray technology for identifying the differences in gene expression patterns between the histological types of endometrial cancer have permitted the identification of differentially expressed genes that could help us to understand differences in the biology and the clinical outcome between histiotypes. In our laboratory, we have recently isolated and characterized two new transcription factors, ETV5 and RUNX1, which expression appears to be associated with initial steps of myometrial infiltration in endometrioid endometrial carcinoma. These studies, as well as those on other genes involved in the mitotic checkpoint as a major mechanism of carcinogenesis in non-endometrioid endometrial cancer, represent examples of how useful large genetic screenings can be for understanding the tumorigenesis process and the future directions in the molecular pathogenesis of endometrial cancer

Two band gap field-dependent thermal conductivity of MgB2MgB_2

The thermal conductivity $\kappa (H,T)$ of the new superconductor $MgB_2$ was studied as a function of the temperature and a magnetic field. No anomaly in the thermal conductivity $\kappa (H,T)$ is observed around the superconducting transition in absence or presence of magnetic fields up to 14 Tesla; upon that field the superconductivity of $MgB_2$ persisted. The thermal conductivity in zero-field shows a $T$-linear increase up to 50K. The thermal conductivity is found to increase with increasing field at high fields. We interpret the findings as if there are two subsystems of quasiparticles with different field-dependent characters in a two ($L$ and $S$)-band superconductor reacting differently with the vortex structure. The unusual enhancement of $\kappa (H ,T)$ at low temperature but higher than a ($H_{c2S}\simeq 3T$) critical field is interpreted as a result of the overlap of the low energy states outside the vortex cores in the $S$-band.Comment: 6 pages,3 figure