Theorem on the Distribution of Short Time Single Particle Displacements

The distribution of the initial very short-time displacements of a single particle is considered for a class of classical systems with Gaussian initial velocity distributions and arbitrary initial particle positions. A very brief sketch is given of a rather intricate and lengthy proof that for this class of systems the nth order cumulants behave as t^{2n} for all n>2, rather than as t^{n}. We also briefly discuss some physical consequences for liquids.Comment: Short 8 page pedagogical review of cond-mat/0505734 for Proc. of "News, Expectations and Trends in Statistical Physics", Crete 200

Effect of Chain Stiffness on the Structure of Single-Chain Polymer Nanoparticles

Polymeric single-chain nanoparticles (SCNPs) are soft nano-objects synthesized by purely intramolecular cross-linking of single polymer chains. By means of computer simulations, we investigate the conformational properties of SCNPs as a function of the bending stiffness of their linear polymer precursors. We investigate a broad range of characteristic ratios from the fully flexible case to those typical of bulky synthetic polymers. Increasing stiffness hinders bonding of groups separated by short contour distances and increases looping over longer distances, leading to more compact nanoparticles with a structure of highly interconnected loops. This feature is reflected in a crossover in the scaling behaviour of several structural observables. The scaling exponents change from those characteristic for Gaussian chains or rings in $\theta$-solvents in the fully flexible limit, to values resembling fractal or `crumpled' globular behaviour for very stiff SCNPs. We characterize domains in the SCNPs. These are weakly deformable regions that can be seen as disordered analogues of domains in disordered proteins. Increasing stiffness leads to bigger and less deformable domains. Surprisingly, the scaling behaviour of the domains is in all cases similar to that of Gaussian chains or rings, irrespective of the stiffness and degree of cross-linking. It is the spatial arrangement of the domains which determines the global structure of the SCNP (sparse Gaussian-like object or crumpled globule). Since intramolecular stiffness can be varied through the specific chemistry of the precursor or by introducing bulky side groups in its backbone, our results propose a new strategy to tune the global structure of SCNPs.Comment: 20 pages, 17 figure

The C Terminus of the Ribosomal-Associated Protein LrtA Is an Intrinsically Disordered Oligomer

The 191-residue-long LrtA protein of Synechocystis sp. PCC 6803 is involved in post-stress survival and in stabilizing 70S ribosomal particles. It belongs to the hibernating promoting factor (HPF) family, intervening in protein synthesis. The protein consists of two domains: The N-terminal region (N-LrtA, residues 1-101), which is common to all the members of the HPF, and seems to be well-folded; and the C-terminal region (C-LrtA, residues 102-191), which is hypothesized to be disordered. In this work, we studied the conformational preferences of isolated C-LrtA in solution. The protein was disordered, as shown by computational modelling, 1D-H-1 NMR, steady-state far-UV circular dichroism (CD) and chemical and thermal denaturations followed by fluorescence and far-UV CD. Moreover, at physiological conditions, as indicated by several biochemical and hydrodynamic techniques, isolated C-LrtA intervened in a self-association equilibrium, involving several oligomerization reactions. Thus, C-LrtA was an oligomeric disordered protein.This research was funded by Spanish Ministry of Economy and Competitiveness [CTQ2015-64445-R (to J.L.N.) and MAT2015-63704-P (to A.A.), with Fondo Social Europeo (ESF)], and by the Basque Government [IT-654-13 (to A.A.)

Combination of suicide and cytokine gene therapies as surgery adjuvant for canine mammary carcinoma

The incidence of canine mammary carcinoma varies with age, breed, and spay status, being among the main tumors appearing in intact female dogs. Thirty-six canine mammary carcinoma patients received injections of canine interferon-β (cIFN-β) and HSV-thymidine kinase/ganciclovir (HSV-tk/GCV) carrying lipoplexes, into the tumor bed, immediately after surgery. Next, they started periodic subcutaneous injections of lipoplexes carrying a human granulocyte-macrophage colony stimulating factor and interleukin-2mixedwith allogeneicmammary carcinoma extracts. This combined strategy was safe and well tolerated. In addition, only two out of 26 patients treated with complete surgery developed a local relapse, and 0 out of 29 stage II and III patients displayed distant metastases, suggesting both local and systemic antitumor activities. The most encouraging result was the long survival times: 22 > 1 year (where 13 > 2 and 4 > 3 years), while maintaining a good quality of life. The preliminary results in five patients presenting with local disease, an additional HSV-tk/GCV plus cIFN-β gene treatment induced local antitumor activity, evidenced by four objective responses (one complete, three partial) and one stable disease. This successful outcome supports further studies to validate this approach not only for canine veterinary patients, but also for translation to human patients.Fil: Finocchiaro, Liliana Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Dr. Ángel Roffo". Unidad de Transferencia Genética; ArgentinaFil: Spector, Agustina I. M.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Dr. Ángel Roffo". Unidad de Transferencia Genética; ArgentinaFil: Agnetti, Lucrecia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Dr. Ángel Roffo". Unidad de Transferencia Genética; ArgentinaFil: Arbe, María Florencia. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Dr. Ángel Roffo". Unidad de Transferencia Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Glikin, Gerardo Claudio. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Dr. Ángel Roffo". Unidad de Transferencia Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The C Terminus of the Ribosomal-Associated Protein LrtA Is an Intrinsically Disordered Oligomer

The 191-residue-long LrtA protein of Synechocystis sp. PCC 6803 is involved in post-stress survival and in stabilizing 70S ribosomal particles. It belongs to the hibernating promoting factor (HPF) family, intervening in protein synthesis. The protein consists of two domains: The N-terminal region (N-LrtA, residues 1-101), which is common to all the members of the HPF, and seems to be well-folded; and the C-terminal region (C-LrtA, residues 102-191), which is hypothesized to be disordered. In this work, we studied the conformational preferences of isolated C-LrtA in solution. The protein was disordered, as shown by computational modelling, 1D-H-1 NMR, steady-state far-UV circular dichroism (CD) and chemical and thermal denaturations followed by fluorescence and far-UV CD. Moreover, at physiological conditions, as indicated by several biochemical and hydrodynamic techniques, isolated C-LrtA intervened in a self-association equilibrium, involving several oligomerization reactions. Thus, C-LrtA was an oligomeric disordered protein.This research was funded by Spanish Ministry of Economy and Competitiveness [CTQ2015-64445-R (to J.L.N.) and MAT2015-63704-P (to A.A.), with Fondo Social Europeo (ESF)], and by the Basque Government [IT-654-13 (to A.A.)

La dimensión erótica del cuidado de sí en el Cármides de Platón

Tal como apunta Foucault, el cuidado de sí está obligado a pasar por la relación con algún otro que es el maestro. A diferencia de la concepción tradicional, que ve en el maestro al encargado de transmitir un conocimiento, como si fuese un bien en el marco de una transacción, la paideia socrática ubica al filósofo como mediador en la relación consigo mismo del discípulo. En este trabajo nos ocuparemos de analizar la dimensión erótica que atraviesa al cuidado de sí. Para ello tomaremos como referencia el diálogo Cármides, que nos ofrece un buen ejemplo de la dinámica entre el discípulo y el maestro, a propósito del cuidado del alma. Asimismo, trabajaremos algunos pasajes del Fedro que nos darán herramientas para echar luz sobre los aspectos eróticos presentes en la relación entre Sócrates y Cármides. Antes de introducirnos de lleno en el análisis, es necesario dejar en claro algunos aspectos sobre la noción de "maestro". Para ello debemos recurrir a la práctica socrática descripta, a grandes rasgos, en la Apología. Allí la puesta en palabras del modus operandi de Sócrates está en concordancia con lo que vemos en los diálogos, excepto por una declaración que es significativa para nuestro trabajo; me refiero a aquel pasaje donde Sócrates dice que él nunca ha sido maestro de nadie y no tiene ningún discípulo (Apología, 33a5-6). Esta afirmación ha generado un debate acerca de la figura de Sócrates como maestro, y a los fines de este trabajo nos obliga a tomar una posición al respecto. Seguimos la lectura de Scott, según la cual el sentido del término "maestro" (didáskalos) en el contexto de la Apología está determinado por la concepción que la audiencia (en este caso, sus acusadores) tiene acerca de esa noción. Es decir, Sócrates no es un maestro al modo de los sofistas, quienes ofrecían su conocimiento a cambio de dinero, o garantizaban el acceso a un conocimiento o técnica. Justamente, Sócrates se desmarca de ese sentido del término, siguiendo un modo filosófico de enseñar, vinculado al conocimiento de uno mismo y a la transformación que forma parte del cuidado de sí. En la misma línea, la dimensión erótica que nos interesa explorar no se trata del intercambio de favores entre el amado y el amante, sino que nuestro trabajo está orientado al análisis de la figura del amante como mediador en la relación consigo mismo del amado.Facultad de Humanidades y Ciencias de la Educació

El proyecto Eskolaberri: evaluación de una experiencia de formación de directivos escolares para la integración de la nueva tecnología en centros de Educación Primaria

En este artículo presentamos los resultados de un análisis descriptivo de un estudio cualitativo con medidas pre y post tratamiento, sobre una experiencia de formación de directivos escolares para la integración de las TIC en las aulas. Actualmente estamos exprimentando este modelo de formación de profesores especialistas en integración curricular de TIC con maestros con responsabilid directiva o de coordinación de proyecto, pertenecientes a once escuelas de Educación Primaria del País Vasco (Spain).In this paper we present the most important conclusions of the in‐service training experience of school directors and selected faculty members on the use and integration of ICTs in Primary Education. Basing our study on the model of continuous improvement of academic quality, we hope to put forth technological, didactic and organizational tools to school directors and administrators permitting them to integrate ICT`s in their classrooms and develop the links and leadership necessary to assure the continuity of these changes in their institutions. Currently, we have developed this model of training in eleven Primary Schools of the Basque Country (Spain)

Elementos miméticos de la anonimia socrática

El trabajo examina el vínculo entre anonimato y mímesis. Sócrates introduce a menudo en los diálogos la palabra de un interlocutor anónimo (τις) quien interroga al filósofo y acompaña a los dialogantes en la búsqueda de la verdad. La participación de este tipo de anónimo aumenta en los diálogos con los sofistas. Precisamente, el Hipias Mayor es el diálogo donde su intervención tiene mayor extensión. Ahí Sócrates utiliza el verbo “miméomai” para describir el modo en que trae a la presencia al interlocutor anónimo. Por esa razón, un análisis de la definición de mímesis de República III nos permitirá echar luz sobre la forma en la cual se presenta el interlocutor anónimo en los diálogos.AbstractThis paper addresses the link between anonymity and mimesis. Often, Socrates introduce into the dialogues an anonymous speaker (τις), who makes questions to the philosopher and goes with the conversational partners seeking the truth. The participation of this anonymous increases in the dialogues with Sophists. In the Hippias Major the presence of the anonimous take part almost all of the dialogue. There, Socrates use the verb “miméomai” to describe the way in wich he bring the anonimous to the presence. Therefore, a critical inquiry into the meaning of mimesis in Republic book 3 allowed us to clarify the way in wich the anonimous takes part into the dialogues

Nanostructuration by self-assembly in N-alkyl thiazolium and triazolium side-chain polymethacrylates

Amphiphilic polymers are tunable systems to construct supramolecular hierarchically self-assembled structures. Six families of heterocyclic polymethacrylates (PMTAs) bearing 1,3-thiazole and 1,2,3-triazole pendant groups with alkyl and succinate spacers were chemically modified by quaternization reaction of the azole heterocycles with five alkylating agents (methyl, butyl, octyl, dodecyl, and hexadecyl iodide) leading to a library of 30 different amphiphilic poly(ionic liquid)s (PMTAs-RI). These polymers have been characterized in bulk by small- and wide-angle X-ray scattering (SAXS, WAXS) and differential scanning calorimetry (DSC). Quaternization induces a dramatic effect (increase) on the glass-transition temperature Tg, being strongest for methyl iodide members. Increasing the length of the quaternizing agent, plasticization is first observed, followed by a further increase of Tg. This effect, together with evidence of a second Tg and crystallization for the members with the longest quaternizing agents, could be attributed to the presence of well-developed alkyl nanodomains evidenced by the structural investigation. WAXS and SAXS results have been consistently interpreted by assuming nanostructuration driven by the amphiphilicity balance of poly(ionic liquid)s. The different morphologies revealed by SAXS have been characterized, assigning a plausible chemical nature to the phases involved in each case. The nonpolar fraction has been considered as the control parameter defining the main features of the achieved morphology. By increasing this parameter, structures ranging from hexagonally packed nonpolar cylinders in a polar matrix to the inverse situation have been found, passing through lamellar phases. Under some conditions, within the polar lamellae a third phase formed by cylinders of heterocycles has even been determined. We have checked the validity of the scenario proposed by comparing the sizes deduced from the SAXS analysis with the expected characteristic lengths of the associated moieties, inferring thereby how alkyl side groups arrange within the nanodomains. On the basis of the complete picture achieved, the type of nanostructures formed by this class of polymers can be predicted, if the chemical composition including the quaternization degree is known.This work has been supported by MAT2013-47902 and MAT2011-24797 (Spanish-MINECO and EU). R.T. acknowledges CSIC for his JAE-Pre grant. A.A. acknowledges financial support from the Projects MAT2012-31088 (Spanish-MINECO and EU) and IT-654-13 (Basque Government).Peer Reviewe