395 research outputs found

    A methodology for the development of historical building archetypes for seismic performance assessment

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    The probabilistic estimation of the magnitude of historical earthquakes requires the analysis of actual building structures affected by those earthquakes. The analysis complicates because most of these buildings no longer exist or were greatly modified, present a great variety of features and the number of analysis for probabilistic assessment is high. As it is not practical to analyze all structures, an alternative is to use structural archetypes representing the affected buildings. This paper presents an approach to develop a quantitative framework for the generation of historical archetypes. The method is illustrated via the definition of a specific archetype for the study and assessment of the effects of the 1763 Komárom earthquake. The historical survey of Tata, Hungary, is assumed as representative of the region and one historical building is utilized to illustrate the archetypes evaluation process

    Space-time evolution of the average river flow in Transylvania Depression

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    Transylvania's physico-geographic factors distinguish it as a well-structured depression unit. Climate and relief features give it an unitary systemic functioning, which can be said about river water runoff. The three main rivers are well monitored by hydrometric stations located at the limits of the region. The length of flow strings has allowed real river flow analysis. Correlations between flow and time demonstrate the land’s systemic unity from a hydrological point of view. The variation of annual, seasonal and monthly averages indicates unitary variation laws. The values of the specific flow and the depth of surface runoff highlight the influence of the local factors, which incubate flow differentials

    An adjustable law of motion for relativistic spherical shells

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    A classical and a relativistic law of motion for an advancing shell are deduced applying the thin layer approximation. A new parameter connected with the quantity of absorbed matter in the expansion is introduced; this allows of matching theory and observation.Comment: 15 pages, 10 figures and article in press; Central European Journal of Physics 201

    Membrane fluidity matters: Hyperthermia from the aspects of lipids and membranes

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    Hyperthermia is a promising treatment modality for cancer in combination both with radio- and chemotherapy. In spite of its great therapeutic potential, the underlying molecular mechanisms still remain to be clarified. Due to lipid imbalances and 'membrane defects' most of the tumour cells possess elevated membrane fluidity. However, further increasing membrane fluidity to sensitise to chemo-or radiotherapy could have some other effects. In fact, hyperfluidisation of cell membrane induced by membrane fluidiser initiates a stress response as the heat shock protein response, which may modulate positively or negatively apoptotic cell death. Overviewing some recent findings based on a technology allowing direct imaging of lipid rafts in live cells and lipidomics, novel aspects of the intimate relationship between the 'membrane stress' of tumour cells and the cellular heat shock response will be highlighted. Our findings lend support to both the importance of membrane remodelling and the release of lipid signals initiating stress protein response, which can operate in tandem to control the extent of the ultimate cellular thermosensitivity. Overall, we suggest that the fluidity variable of membranes should be used as an independent factor for predicting the efficacy of combinational cancer therapies

    Identification of sex hormone-binding globulin in the human hypothalamus

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    Gonadal steroids are known to influence hypothalamic functions through both genomic and non-genomic pathways. Sex hormone-binding globulin ( SHBG) may act by a non-genomic mechanism independent of classical steroid receptors. Here we describe the immunocytochemical mapping of SHBG-containing neurons and nerve fibers in the human hypothalamus and infundibulum. Mass spectrometry and Western blot analysis were also used to characterize the biochemical characteristics of SHBG in the hypothalamus and cerebrospinal fluid (CSF) of humans. SHBG-immunoreactive neurons were observed in the supraoptic nucleus, the suprachiasmatic nucleus, the bed nucleus of the stria terminalis, paraventricular nucleus, arcuate nucleus, the perifornical region and the medial preoptic area in human brains. There were SHBG-immunoreactive axons in the median eminence and the infundibulum. A partial colocalization with oxytocin could be observed in the posterior pituitary lobe in consecutive semithin sections. We also found strong immunoreactivity for SHBG in epithelial cells of the choroid plexus and in a portion of the ependymal cells lining the third ventricle. Mass spectrometry showed that affinity-purified SHBG from the hypothalamus and choroid plexus is structurally similar to the SHBG identified in the CSF. The multiple localizations of SHBG suggest neurohypophyseal and neuroendocrine functions. The biochemical data suggest that CSF SHBG is of brain rather than blood origin. Copyright (c) 2005 S. Karger AG, Base

    Playing the victim? Human trafficking, African youth, and geographies of structural inequality

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    This article explores the role of agency in determining who is and is not considered to be a legitimate victim of human trafficking. It draws on critical human trafficking scholarship and research on the life chances of West African youth. This is complemented by qualitative data from youth embroiled in football-related human trafficking. The insights from these analyses are brought into conversation with theoretical work on the geographies of commodities. This results in the concept of ‘unveiling the football trafficking fetish’, which is used to theorise how and why the agency of mobile youthful African male bodies undermines their claims of being trafficked human beings. The findings that emerge are significant in two ways. First, they generate theoretical insights on the coexistence of agency and exploitation in young lives, and how young people’s aspirations and agency can be (mis)read and work against them. Second, they provide a unique illustration of how human trafficking is a product of capitalism yet can be presented as a form of behaviour that lies outside of capitalist social relations. To centre these social relations and foster new forms of critical dialogue within and beyond population geography, the article concludes by recommending we consider the implications of conceptualising people as susceptible to rather than vulnerable to human trafficking

    Identification of the nonlinear steering dynamics of an autonomous vehicle

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    Automated driving applications require accurate vehicle specific models to precisely predict and control the motion dynamics. However, modern vehicles have a wide array of digital and mechatronic components that are difficult to model, manufactures do not disclose all details required for modelling and even existing models of subcomponents require coefficient estimation to match the specific characteristics of each vehicle and their change over time. Hence, it is attractive to use data-driven modelling to capture the relevant vehicle dynamics and synthesise model-based control solutions. In this paper, we address identification of the steering system of an autonomous car based on measured data. We show that the underlying dynamics are highly nonlinear and challenging to be captured, necessitating the use of data-driven methods that fuse the approximation capabilities of learning and the efficiency of dynamic system identification. We demonstrate that such a neural network based subspace-encoder method can successfully capture the underlying dynamics while other methods fall short to provide reliable results

    Heat stress causes spatially-distinct membrane re-modelling in K562 leukemia cells

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    Cellular membranes respond rapidly to various environmental perturbations. Previously we showed that modulations in membrane fluidity achieved by heat stress (HS) resulted in pronounced membrane organization alterations which could be intimately linked to the expression and cellular distribution of heat shock proteins. Here we examine heat-induced membrane changes using several visualisation methods. With Laurdan two-photon microscopy we demonstrate that, in contrast to the enhanced formation of ordered domains in surface membranes, the molecular disorder is significantly elevated within the internal membranes of cells preexposed to mild HS. These results were compared with those obtained by anisotropy, fluorescence lifetime and electron paramagnetic resonance measurements. All probes detected membrane changes upon HS. However, the structurally different probes revealed substantially distinct alterations in membrane heterogeneity. These data call attention to the careful interpretation of results obtained with only a single label. Subtle changes in membrane microstructure in the decision-making of thermal cell killing could have potential application in cancer therapy

    Electrospinning scale-up and formulation development of PVA nanofibers aiming oral delivery of biopharmaceuticals

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    Electrospinning is a promising drying technology providing a rapid and gentle drying at ambient temperature, thus electrospinning of polyvinyl alcohol aqueous solutions was investigated for the solid formulation of biopharmaceuticals. The commonly used single-needle electrospinning does not have adequate productivity to satisfy the industrial requirements, therefore our aim was to study the scale-up of the technology by using high-speed electrospinning. High molecular weight polyethylene oxide as a secondary polymer was applied to enhance the fiber formation of polyvinyl alcohol. While polyvinyl alcohol-polyethylene oxide formulations resulted in adequate fiber formation it was not possible to process them further as the friability of the fibers was too low. In order to increase the friability, the effect of adding various sugars (mannitol, glucose, lactose, saccharose, and trehalose) was investigated. The results showed that mannitol was the best friability enhancing excipient because of its crystallinity and low moisture content in the fibrous sample. In contrast, glucose, lactose, saccharose, and trehalose were amorphous with higher moisture content and fibers containing these were grindable only after post-drying
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