406 research outputs found

    Hardware Software Synthesis of a H.264 / AVC Baseline Profile Decoder

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    The latest video compression standard is a joint effort between ITU and MPEG known as H.264/AVC. As with any video compression standard the H.264/AVC uses computationally intensive algorithms to maximize performance. During decompression these algorithms must be applied in real-time, processing 30 frames a second. This can be done in software, specialized hardware, or a combination of the two. Software solutions allow for maximum portability and ease of design, but General Purpose Processors (GPP) can not take full advantage of the parallelizable algorithms that the H.264 decoder is based upon. Specialized hardware solutions, on the other hand, allow concurrent data and instruction paths, but do not offer a high level of abstraction for cross platform development. Recent work by Xilinx has resulted in the advent of the MicroBlaze soft-processor that is a stand alone microcontroller built from an FPGA. The MicroBlaze provides a specialized hardware medium to run software on-chip with VHDL entities. The goal of this thesis was to model and simulate a software hardware hybrid H.264/AVC Baseline Profile decoder using VHDL and a soft-processor. It was proposed to divide all highly sequential calculations (run-length and CALVC decoding) and control data flow into software and perform the remaining calculations (prediction, inverse transform, inverse quantization, etc.) in hardware modules. The software runs on Xilinx\u27 s MicroBlaze soft-processor and the hardware was designed using VHDL. A major advantage of soft-processors over GPP\u27s, is that it hardware instantiations reside on-chip with the processor. The software and MicroBlaze soft-processor were simulated in a test bench and the results proved that the MicroBlaze could not handle the encoded bit-stream in real-time. For this reason the hardware interface and hardware decoder were never fully implemented. The scope of the thesis covers the H.264 Baseline Profile standard, MicroBlaze processor, the implemented software solution, and the proposed hardware counterpart

    Dendrimers Clicked Together Divergently

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    ABSTRACT: Dendrimers containing 1,4-triazole linkages between each generation were grown divergently via the Click chemistry inspired Huisgen 1,3-dipolar cycloaddition reaction in the presence of a Cu(I) catalyst. The monomeric unit (1-propargylbenzene-3,5-dimethanol) contained the alkyne functionality, while the core (1,2-bis(2-azidoethoxy)ethane) and growing dendrimers presented the azide groups necessary for this type of Click reaction. The first generation dendrimer was also functionalized with alkyne termini to demonstrate an alternative pathway allowed by this chemistry. Synthesis and characterization, with infrared (IR), 1H and 13C NMR spectroscopies, high-resolution mass spectrometry, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), are reported for these divergently grown dendrimers

    Heterogeneous Catalysis through Microcontact Printing

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    Here, we investigate four different chemical pathways (Scheme 1a–d) relevant to the Cu-catalyzed azide–alkyne cycloaddition (CuAAC) reaction.[13] Three of those pathways lead to surfaces functionalized with organic molecules.[5, 11, 14] At the outset, our practical goal was to identify surface-functionalization protocols that are capable of attaining 1) spatial selectivity, 2) high surface coverage, and 3) rapid reaction kinetics. Our ultimate goal is to achieve a fundamental understanding of how different reaction pathways influence the chemical outcome as it applies to the organic functionalization of surfaces

    Towards a rational design of solid drug nanoparticles with optimised pharmacological properties.

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    Solid drug nanoparticles (SDNs) are a nanotechnology with favourable characteristics to enhance drug delivery and improve the treatment of several diseases, showing benefit for improved oral bioavailability and injectable long-acting medicines. The physicochemical properties and composition of nanoformulations can influence the absorption, distribution, and elimination of nanoparticles; consequently, the development of nanoparticles for drug delivery should consider the potential role of nanoparticle characteristics in the definition of pharmacokinetics. The aim of this study was to investigate the pharmacological behaviour of efavirenz SDNs and the identification of optimal nanoparticle properties and composition. Seventy-seven efavirenz SDNs were included in the analysis. Cellular accumulation was evaluated in HepG2 (hepatic) and Caco-2 (intestinal), CEM (lymphocyte), THP1 (monocyte), and A-THP1 (macrophage) cell lines. Apparent intestinal permeability (Papp) was measured using a monolayer of Caco-2 cells. The Papp values were used to evaluate the potential benefit on pharmacokinetics using a physiologically based pharmacokinetic model. The generated SDNs had an enhanced intestinal permeability and accumulation in different cell lines compared to the traditional formulation of efavirenz. Nanoparticle size and excipient choice influenced efavirenz apparent permeability and cellular accumulation, and this appeared to be cell line dependent. These findings represent a valuable platform for the design of SDNs, giving an empirical background for the selection of optimal nanoparticle characteristics and composition. Understanding how nanoparticle components and physicochemical properties influence pharmacological patterns will enable the rational design of SDNs with desirable pharmacokinetics

    'Double or quits': perceptions and management of organ transplantation by adults with cystic fibrosis

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    Medical sociologists have often considered lay perceptions of the risks of medical interventions, yet in many empirical studies respondents are people who are not likely to be exposed to a particular intervention. Furthermore, it has been well documented that risk perceptions may change over time and with diminishing health state. This paper explores perceptions and management of the risks of organ transplantation amongst adults with cystic fibrosis (CF), the most common autosomal recessive genetic disease in the UK. Although the focus of medical research is now on providing gene replacement therapy to this group, transplantation is currently the last treatment that an adult with CF can be offered when all other treatment has failed to maintain their health. Thirty-one respondents with varying degrees of health state from a specialist CF centre were interviewed as part of a larger study concerning perceptions of health and risks of treatment. Interviews were audiotaped, transcribed and analysed using ATLAS-ti. During analysis respondents' transcripts were divided into two groups: firstly those who did not anticipate needing a transplant in the near future (if at all) and secondly those who were currently being considered for transplantation, on the transplant list, or who had already received donor organs. The paper focuses on themes arising from interview transcripts and finds that although the focus of risk differs between the two groups, the influence of luck is perceived as strong for both groups and emotion work features heavily in those undergoing the transplant process. Contrary to previous research, fears of inheriting donor characteristics are not found amongst adults with CF, but rather body components are commodified when talking of both giving and receiving organs. © 2002 Elsevier Science Ltd. All rights reserved

    Design and Synthesis of Binding Growth Factors

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    Growth factors play important roles in tissue regeneration. However, because of their instability and diffusible nature, improvements in their performance would be desirable for therapeutic applications. Conferring binding affinities would be one way to improve their applicability. Here we review techniques for conjugating growth factors to polypeptides with particular affinities. Conjugation has been designed at the level of gene fusion and of polypeptide ligation. We summarize and discuss the designs and applications of binding growth factors prepared by such conjugation approaches

    Bioresponsive Mesoporous Silica Nanoparticles for Triggered Drug Release

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    Mesoporous silica nanoparticles (MSNPs) have garnered a great deal of attention as potential carriers for therapeutic payloads. However, achieving triggered drug release from MSNPs in vivo has been challenging. Here, we describe the synthesis of stimulus-responsive polymer-coated MSNPs and the loading of therapeutics into both the core and shell domains. We characterize MSNP drug-eluting properties in vitro and demonstrate that the polymer-coated MSNPs release doxorubicin in response to proteases present at a tumor site in vivo, resulting in cellular apoptosis. These results demonstrate the utility of polymer-coated nanoparticles in specifically delivering an antitumor payload.National Science Foundation (U.S.) (grant R01-CA124427)National Science Foundation (U.S.) (grant U54-CA119349)National Science Foundation (U.S.) (grant U54-CA119335

    Tratamiento del cuerpo y control social entre los mayas itzaes, siglos XVII-XVIII

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    In many societies the human body is considered as a cosmological model and therefore of society. In the case of the Maya Itza we know that the human body is a reference to their territorial, social and religious organization. In this paper we analyze the importance of the human body as a symbolic model, focusing on aspects of Itza religion and rituals, related to the transformation and modification of the human body. We will analyze how Itza society controlled a population with the ability of transfiguration.En diversas sociedades el cuerpo humano se ha concebido como un modelo cosmológico y por lo tanto de la sociedad. En el caso de los mayas itzaes sabemos que el cuerpo humano es un referente para la organización territorial, social y religiosa. En este trabajo se analiza la importancia del cuerpo humano como modelo simbólico, centrándonos en aspectos de la religión y rituales itzaes relacionados con la transformación y modificación del cuerpo humano en el período colonial. Se examina el control que ejerció la sociedad itzá con respecto a una población con la capacidad de transfiguración

    Shadows of the colonial past – diverging plant use in Northern Peru and Southern Ecuador

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    This paper examines the traditional use of medicinal plants in Northern Peru and Southern Ecuador, with special focus on the Departments of Piura, Lambayeque, La Libertad, Cajamarca, and San Martin, and in Loja province, with special focus on the development since the early colonial period. Northern Peru represents the locus of the old Central Andean "Health Axis." The roots of traditional healing practices in this region go as far back as the Cupisnique culture early in the first millennium BC
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