Shape anisotropy of a single random-walk polymer

Random walks have been used to describe a wide variety of systems ranging from cell colonies to polymers. Sixty-five years ago, Kuhn [Kuhn, W. (1934) Kolloid-Z. 68, 2–11] made the prediction, backed later by computer simulations, that the overall shape of a random-walk polymer is aspherical, yet no experimental work has directly tested Kuhn's general idea and subsequent computer simulations. By using fluorescence microscopy, we monitored the conformation of individual, long, random-walk polymers (fluorescently labeled DNA molecules) at equilibrium. We found that a polymer most frequently adopts highly extended, nonfractal structures with a strongly anisotropic shape. The ensemble-average ratio of the lengths of the long and short axes of the best-fit ellipse of the polymer was much larger than unity.

Synthesis and characterisation of imprinted polymeric receptor mimics

Molecularly imprinted polymers (MIPs) are crosslinked polymers containing bespoke functionalised cavities arising from the inclusion of template molecules in the polymerisation mixture and their later extraction. When the polymers are prepared functional polymerisable monomers are included which become part of the polymer matrix and serve to decorate the cavities with functionality appropriate to the template molecules. Overall, binding sites are created which have a memory for the template both in terms of shape and matching functionality. Fluorescent molecularly imprinted polymers have the benefit of a fluorophore in their cavities that may respond to the presence of bound test compound by a change in their fluorescence output. The work presented falls into three main areas. A series of fluorescent MIPs was prepared with a view to generating material capable of mimicking the binding characteristics of the metabolically important cytochrome isoform CYP2D6. The MIPs re-bound their templates and various cross-reactivities were encountered for test compound/drug recognition. One MIP in particular exhibited a rational discrimination amongst the related synthetic templates and was reasonably successful in recognising CYP2D6 substrates from the drug set tested. In order to give some insights into binding modes in MIPs, attempts were made to produce functional monomers containing two or more fluorophores that could be interrogated independently. A model compound was prepared which fitted the dual-fluorophore criteria and which will be the basis for future incorporation into MIPs. A further strand to this thesis is the deliberate incorporation of hydrophobic moieties into fluorescent functional monomers so that the resulting imprinted cavities might be biomimetic in their impersonation of enzyme active sites. Thus the imprinted cavities had specific hydrophobic regions as well as the usual polar functionality with which to interact with binding test compounds.

Plato on Oblivion. About Memory and Forgetfullness in the Platonic Dialogues

The aim of this paper is to tackle the role of oblivion in the Plato’s dialogues. It takes as work texts the dialogues where the anamnesis doctrine is exposed, and from these writings, but also attending to several other ones, the connexions between oblivion and other Platonic issues, as, e. g., language, memory, experience or love are explored, in order to clarify their relations of mutual dependence. In this way, we attempt to find out in the Platonic oblivion a philosophical sense, which is not disdainful in comparison with the sense and the relevance that the readers of all times have granted to anamnesis; for anamnesis and oblivion are inseparable indeed.

La presencia del "flâneur" en "Tetralogie der Erinnerung" de Dieter Forte

Reflejando la ciudad moderna, el flâneur se encuentra atrapado entre dos tiempos: el presente, que se transforma continuamente, y el pasado, que permanece en forma de vestigios materiales. Desde su aparición en la literatura, la trayectoria del flâneur va ligada a los principales cambios históricos, sociales y culturales, que se plasman en distintas texturas urbanas. En todas ellas ejerce una función de nexo entre la ciudad antigua y la nueva que se superpone. El objeto del presente artículo es analizar la evolución de esta figura histórico y literaria como punto de partida para interpretar la obra en prosa Tetralogie der Erinnerung (1992-2004) de Dieter Forte.

Characterisation of polyethylene powders for rotational moulding and effect of powder size and shape on densification behaviour

The particle size, shape and distribution of a range of rotational moulding polyethylenes (PEs) ground to powder was investigated using a novel visual data acquisition and analysis system (TP Picture®), developed by Total Petrochemicals. Differences in the individual particle shape factors of the powder samples were observed and correlations with the grinding conditions were determined. When heated, the bubble dissolution behaviour of the same powders was investigated and the shape factor correlated with densification rate, bubble size and bubble distribution.

Memory lineage of Ansúrez: the funerary monument in Gordaliza del Pino (León).

The discovery of the mural on the walls of the church of Santa Maria de Arbas of the town of Leon Gordaliza del Pino has been a revelation. The funerary monument called Knight Gordali-za addition to its artistic value , has a historical value that try to reflect in this study and that clears some questions about the his-tory of the kingdom of Leon, and specifically about the lineage of Ansúrez.

Deep into fragile memory: the other secretaries of the Holy Office.

The secretaries of the secret were an essential element of the Holy Office’s district courts. They were in charge of record-ing and writing all of the official documents of these tribunals, but also of keeping the archive in order. And not only of these, so they were not the simple bureaucrats that the traditional historians wrote about. In fact, their long working hours turned a unique and much defined office into a complex taxonomy of professionals who shared the secretaries of the secret’s concerns but not their privileges. This paper aims to go in depth into these profession-als’ current life. They were not officials, but they take care of some important duties even if they were not getting paid for it.

Implication of GluR2 subunit of AMPA receptor in RGS14(414)-mediated memory enhancement

Ongoing quest for finding treatment against memory loss seen in aging and in many neurological and neurodegenerative diseases, so far has been unsuccessful and memory enhancers are seen as a potential remedy against this brain dysfunction. Recently, we showed that gene corresponding to a protein called regulator of G-protein signaling 14 of 414 amino acids (RGS14414) is a robust memory enhancer (Lopez-Aranda et al. 2009: Science). RGS14414-treatment in area V2 of visual cortex caused memory enhancement to such extent that it converted short-term object recognition memory (ORM) of 45min into long lasting long-term memory that could be traced even after many months. Now, through targeting of multiple receptors and molecules known to be involved in memory processing, we found that GluR2 subunit of AMPA receptor might be key to memory enhancement in RGS-animals. RGS14-animals showed a progressive increase in GluR2 protein expression while processing an object information which reached to highest level after 60min of object exposure, a time period required for conversion of short-term ORM into long-term memory in our laboratory set up. Normal rats could retain an object information in brain for 45min (short-term) and not for 60min. However, RGS-treated rats are able to retain the same information for 24h or longer (long-term). Therefore, highest expression of GluR2 subunit seen at 60min suggests that this protein might be key in memory enhancement and conversion to long-term memory in RGS-animals. In addition, we will also discuss the implication of Hebbian plasticity and interaction of brain circuits in memory enhancement.

Aplicação de Ligas com Memória de Forma como Dispositivos de Segurança

As ligas com memória de forma Ni-Ti apresentam diversas características bastante úteis, das quais podemos realçar a sua elevada resistência à corrosão, às vibrações e geração de forças superiores quando comparadas com outros atuadores. Estas ligas apresentam diversas áreas de aplicabilidade em diferentes aéreas de pesquisa, como a metalomecânica, a robótica, aplicações espaciais, sendo mais relevante para este trabalho a sua aplicação em mecanismos de segurança para portas e acessos. Com este trabalho, pretendemos contribuir para uma forma eficaz de combate e contenção de incêndios em navios, através da apresentação de um mecanismo que vai permitir o corte de ventilação e isolamento no local do incêndio, permitindo criar uma fronteira de fumos que levará ao combate do incêndio por asfixia. O trabalho descreve um mecanismo idealizado com a utilização de ligas com memória de forma, que vai proceder à libertação de um flap, para isolamento da ventilação, na presença de temperatura proveniente do incêndio. Descreve também ensaios termomecânicos realizados, para determinação das características das molas e seu comportamento em determinadas situações chave. Para isto, irão ser utilizadas duas molas com diferentes gamas de temperatura, com o intuito de demonstrar a eficácia na utilização de diversos atuadores de ligas com memória de forma. Todos os testes foram feitos na presença de gamas de temperatura que se assemelham aos valores de atuação dos sistemas automáticos de extinção por água, pelo que os resultados obtidos, ilustram a verdadeira eficácia e utilidade do mecanismo, em casos reais.

RGS14 (414)-mediated prevention of an episodic memory loss: a study of molecular mechanism

A large proportion of human populations suffer memory impairments either caused by normal aging or afflicted by diverse neurological and neurodegenerative diseases. Memory enhancers and other drugs tested so far against memory loss have failed to produce therapeutic efficacy in clinical trials and thus, there is a need to find remedy for this mental disorder. In search for cure of memory loss, our laboratory discovered a robust memory enhancer called RGS14(414). A treatment in brain with its gene produces an enduring effect on memory that lasts for lifetime of rats. Therefore, current thesis work was designed to investigate whether RGS14(414) treatment can prevent memory loss and furthermore, explore through biological processes responsible for RGS-mediated memory enhancement. We found that RGS14(414) gene treatment prevented episodic memory loss in rodent models of normal aging and Alzheimer´s disease. A memory loss was observed in normal rats at 18 months of age; however, when they were treated with RGS14(414) gene at 3 months of age, they abrogated this deficit and their memory remained intact till the age of 22 months. In addition to normal aging rats, effect of memory enhancer treatment in mice model of Alzheimer´s disease (AD-mice) produced a similar effect. AD-mice subjected to treatment with RGS14(414) gene at the age of 2 months, a period when memory was intact, showed not only a prevention in memory loss observed at 4 months of age but also they were able to maintain normal memory after 6 months of the treatment. We posit that long-lasting effect on memory enhancement and prevention of memory loss mediated through RGS14(414) might be due to a permanent structural change caused by a surge in neuronal connections and enhanced neuronal remodeling, key processes for long-term memory formation. A neuronal arborization analysis of both pyramidal and non-pyramidal neurons in brain of RGS14(414)-treated rats exhibited robust rise in neurites outgrowth of both kind of cells, and an increment in number of branching from the apical dendrite of pyramidal neurons, reaching to almost three times of the control animals. To further understand of underlying mechanism by which RGS14(414) induces neuronal arborization, we investigated into neurotrophic factors. We observed that RGS14 treatment induces a selective increase in BDNF. Role of BDNF in neuronal arborization, as well as its implication in learning and memory processes is well described. In addition, our results showing a dynamic expression pattern of BDNF during ORM processing that overlapped with memory consolidation further support the idea of the implication of this neurotrophin in formation of long-term memory in RGS-animals. On the other hand, in studies of expression profiling of RGS-treated animals, we have demonstrated that 14-3-3ζ protein displays a coherent relationship to RGS-mediated ORM enhancement. Recent studies have demonstrated that the interaction of receptor for activated protein kinase 1 (RACK1) with 14-3-3ζ is essential for its nuclear translocation, where RACK1-14-3-3ζ complex binds at promotor IV region of BDNF and promotes an increase in BDNF gene transcription. These observations suggest that 14-3-3ζ might regulate the elevated level of BDNF seen in RGS14(414) gene treated animals. Therefore, it seems that RGS-mediated surge in 14-3-3ζ causes elevated BDNF synthesis needed for neuronal arborization and enhanced ORM. The prevention of memory loss might be mediated through a restoration in BDNF and 14-3-3ζ protein levels, which are significantly decreased in aging and Alzheimer’s disease. Additionally, our results demonstrate that RGS14(414) treatment could be a viable strategy against episodic memory loss.

HPC Accelerators with 3D Memory

After a decade evolving in the High Performance Computing arena, GPU-equipped supercomputers have con- quered the top500 and green500 lists, providing us unprecedented levels of computational power and memory bandwidth. This year, major vendors have introduced new accelerators based on 3D memory, like Xeon Phi Knights Landing by Intel and Pascal architecture by Nvidia. This paper reviews hardware features of those new HPC accelerators and unveils potential performance for scientific applications, with an emphasis on Hybrid Memory Cube (HMC) and High Bandwidth Memory (HBM) used by commercial products according to roadmaps already announced.

Testimonios de un Pasado Imperfecto : Vida Cotidiana de Mujeres bajo Dictadura en Valparaíso y Viña del Mar, Chile 1980-1987

Este proyecto de investigación se caracteriza como estudio histórico-etnográfica basado en estudios de casos de la vida cotidiana de nueve mujeres en Valparaíso y Viña del Mar durante la dictadura chilena, analizando el testimonio de los efectos del régimen autoritario en la vida cotidiana de estas mujeres chilenas entre 1980 y 1987. La metodología se radica firmemente en el método etnográfico con entrevistas semi-abiertas y el análisis del discurso de los relatos. En la metáfora de la arpillera (un tapiz anónimo cosido en lona ensamblado a partir de piezas de tela que muestra escenas de la vida cotidiana o protesta la dictadura de Pinochet), trozos y pedazos de experiencia se juntan en el encima de la lona de la historia para dar forma al testimonio de vida la vida cotidiana. Este proyecto se centra en tres aspectos diferentes de la relación entre el Estado autoritario y la vida cotidiana: las técnicas de gobernabilidad (macro), narraciones de silencio y miedo (micro) y trayectorias narrados (espacial), el último inspirado por el ensayo Halbwachs en caminar por la ciudad. Para cerrar, la relevancia del estudio se destaca por el intento de comprender el efecto de un estado autoritario en el sujeto femenino y las respuestas y adaptaciones que las mujeres chilenas adoptaron en la vida privada y pública mediada por la violencia y el miedo bajo dictadura. La dialéctica del acontecimiento y la rutina de la vida cotidiana bajo la dictadura se unen en las memorias narradas, mediada por el presente vivido, lo cual permite una reflexión sobre la cuestión de la alteridad en la sociedad chilena.Este proyecto de investigación se caracteriza como estudio histórico-etnográfica basado en estudios de casos de la vida cotidiana de nueve mujeres en Valparaíso y Viña del Mar durante la dictadura chilena, analizando el testimonio de los efectos del régimen autoritario en la vida cotidiana de estas mujeres chilenas entre 1980 y 1987. La metodología se radica firmemente en el método etnográfico con entrevistas semi-abiertas y el análisis del discurso de los relatos. En la metáfora de la arpillera (un tapiz anónimo cosido en lona ensamblado a partir de piezas de tela que muestra escenas de la vida cotidiana o protesta la dictadura de Pinochet), trozos y pedazos de experiencia se juntan en el encima de la lona de la historia para dar forma al testimonio de vida la vida cotidiana. Este proyecto se centra en tres aspectos diferentes de la relación entre el Estado autoritario y la vida cotidiana: las técnicas de gobernabilidad (macro), narraciones de silencio y miedo (micro) y trayectorias narrados (espacial), el último inspirado por el ensayo Halbwachs en caminar por la ciudad. Para cerrar, la relevancia del estudio se destaca por el intento de comprender el efecto de un estado autoritario en el sujeto femenino y las respuestas y adaptaciones que las mujeres chilenas adoptaron en la vida privada y pública mediada por la violencia y el miedo bajo dictadura. La dialéctica del acontecimiento y la rutina de la vida cotidiana bajo la dictadura se unen en las memorias narradas, mediada por el presente vivido, lo cual permite una reflexión sobre la cuestión de la alteridad en la sociedad chilena.

Análisis de los cambios epigenéticos en la metilación del DNA inducidos por la diabetes y sus posibles mecanismos

Los cambios epigenéticos son responsables de la aparición de muchas patologías humanas y sus causas son debido a factores ambientales como genéticos. Se ha descrito en enfermedades crónicas como la Diabetes Mellitus tipo 2 (T2DM) que se caracteriza por los estados de hiperglucemia y el incremento en el estrés oxidativo que conlleva a complicaciones micro y macro vasculares, asociado a una desmetilación global del genoma. Nuestra hipótesis corresponde a que los órganos diana son afectados por las alteraciones como la metilación e hidroximetilación como consecuencia del estrés oxidativo que luego repercuten en la persistencia de la enfermedad. Métodos: A partir de sangre periférica se analizaron los cambios globales en la metilación del DNA que son afectados por el estado metabólico de 60 individuos (40 pacientes, 20 controles sanos). Por técnicas de cuantificación se compararon los resultados obtenidos con los de la expresión de las enzimas involucradas. Por último, se realizó un estudio de microarreglos de metilación del DNA y de expresión obtenidos de la base de datos GEO para así comparar los resultados con nuestros datos experimentales. Resultados: Los pacientes diabéticos con pobre control metabólico presentaron mayores niveles de metilación que el grupo control y no se encontró alteración en las enzimas involucradas en este proceso. Los resultados fueron concordantes con el estudio de microarreglos. Conclusión: Los estudios experimentales y de microarreglos demostraron que la metilación es tejido específico y que existe una mayor oxidación en pacientes. Por ello proponemos una vía alterna de desmetilación no enzimática, basada en la oxidación directa de los grupos metilos generados por los estados oxidativos característicos de esta enfermedad.

The Intrahippocampal Infusion Of Crotamine From Crotalus Durissus Terrificus Venom Enhances Memory Persistence In Rats.

Previous research has shown that crotamine, a toxin isolated from the venom of Crotalus durissus terrificus, induces the release of acetylcholine and dopamine in the central nervous system of rats. Particularly, these neurotransmitters are important modulators of memory processes. Therefore, in this study we investigated the effects of crotamine infusion on persistence of memory in rats. We verified that the intrahippocampal infusion of crotamine (1 μg/μl; 1 μl/side) improved the persistence of object recognition and aversive memory. By other side, the intrahippocampal infusion of the toxin did not alter locomotor and exploratory activities, anxiety or pain threshold. These results demonstrate a future prospect of using crotamine as potential pharmacological tool to treat diseases involving memory impairment, although it is still necessary more researches to better elucidate the crotamine effects on hippocampus and memory.

Metabolic Memory Of ß-cells Controls Insulin Secretion And Is Mediated By Camkii.

Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) functions both in regulation of insulin secretion and neurotransmitter release through common downstream mediators. Therefore, we hypothesized that pancreatic ß-cells acquire and store the information contained in calcium pulses as a form of metabolic memory, just as neurons store cognitive information. To test this hypothesis, we developed a novel paradigm of pulsed exposure of ß-cells to intervals of high glucose, followed by a 24-h consolidation period to eliminate any acute metabolic effects. Strikingly, ß-cells exposed to this high-glucose pulse paradigm exhibited significantly stronger insulin secretion. This metabolic memory was entirely dependent on CaMKII. Metabolic memory was reflected on the protein level by increased expression of proteins involved in glucose sensing and Ca(2+)-dependent vesicle secretion, and by elevated levels of the key ß-cell transcription factor MAFA. In summary, like neurons, human and mouse ß-cells are able to acquire and retrieve information.