1,799 research outputs found

    Variations in the Expression of Inka Power by Richard L. Burger, Craig Morris, and Ramiro Matos Mendieta (eds.)

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65873/1/j.1935-4940.2008.00055.x.pd

    Recent Advances in Maya Archaeology

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    This paper focuses on the discoveries of the last decade in Maya archaeology, and assesses their impact on previous models and synthetic frameworks. Although the bibliography includes 700 items published during the last 10 years, it is not exhaustive; on the contrary, a frustratingly large number of discoveries had to be omitted. Two areas exploding with new research are (1) the elicitation of a greater variety of data from hieroglyphic texts, and (2) a series of chemical and biological breakthroughs in the analysis of human burials. The former make it easier to assess the role of elite actors or “agents” in processes of sociopolitical change. The latter hold out the hope of documenting warfare (through skeletal trauma), migration (by tracing tooth enamel isotopes to ground water), status or gender differences in diet (through bone chemistry), and biological connections of individuals to each other and to earlier populations (through DNA). By combining these new data, we are on our way to integrating humanism and science, and to treating Maya polities as case studies in primary or secondary state formation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44641/1/10814_2004_Article_459122.pd

    Where is Lowland Maya archaeology headed?

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    This article isolates three important trends in Lowland Maya archaeology during the last decade: (1) increased use of the conjunctive approach, with renewed appreciation of context and provenience; (2) waning use of the label “unique” to describe the Maya; and (3) an effort to use the Lowland Maya as a case study in social evolution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44643/1/10814_2005_Article_BF02231486.pd

    A Simple Procedure for Constructing 5'-Amino-Terminated Oligodeoxynucleotides in Aqueous Solution

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    A rapid method for the synthesis of oligodeoxynucleotides (ODNs) terminated by 5'-amino-5'-deoxythymidine is described. A 3'-phosphorylated ODN (the donor) is incubated in aqueous solution with 5'-amino- 5'-deoxythymidine in the presence of N-(3-dimethylaminopropyl)-)N'-ethylcarbodiimide hydrochloride (EDC), extending the donor by one residue via a phosphoramidate bond. Template- directed ligation of the extended donor and an acceptor ODN, followed by acid hydrolysis, yields the acceptor ODN extended by a single 5'-amino-5'-deoxythymidine residue at its 5'terminus

    Design of Low-Voltage Digital Building Blocks and ADCs for Energy-Efficient Systems

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    Increasing number of energy-limited applications continue to drive the demand for designing systems with high energy efficiency. This tutorial covers the main building blocks of a system implementation including digital logic, embedded memories, and analog-to-digital converters and describes the challenges and solutions to designing these blocks for low-voltage operation

    Reduced Drying Time of Anodes for Lithium-Ion Batteries through Simultaneous Multilayer Coating

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    The extended process chain starting from slurry mixing up to the operative lithium-ion battery requires a deep understanding of each individual process step and knowledge of the interaction of the different process steps with each other. In particular, the intertwining of slurry mixing and drying determines the microstructure of the electrode, which in turn affects the performance of the cell. Herein, a scalable multilayer approach is used to tailor electrodes with improved mechanical and electrochemical properties, which disclose their advantages especially at high drying rates. Cryogenic broad ion beam scanning electron microscopy (Cryo-BIB-SEM) micrographs are used to reveal the influences of different process parameters, like slurry formulation, mixing device, and properties of the active material on the intrinsic network between active particles and binders in graphite-based anode slurries. By a chosen combination of these slurries in a multilayer electrode, a tenfold acceleration of the drying time with favorable mechanical and electrochemical properties for full cells derived from these anodes is demonstrated

    Disulfide bond reduction and exchange in C4 domain of von Willebrand factor undermines platelet binding

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    Background The von Willebrand factor (VWF) is a key player in regulating hemostasis through adhesion of platelets to sites of vascular injury. It is a large, multi-domain, mechano-sensitive protein that is stabilized by a net of disulfide bridges. Binding to platelet integrin is achieved by the VWF-C4 domain, which exhibits a fixed fold, even under conditions of severe mechanical stress, but only if critical internal disulfide bonds are closed. Objective To determine the oxidation state of disulfide bridges in the C4 domain of VWF and implications for VWF’s platelet binding function. Methods We combined classical molecular dynamics and quantum mechanical simulations, mass spectrometry, site-directed mutagenesis, and platelet binding assays. Results We show that 2 disulfide bonds in the VWF-C4 domain, namely the 2 major force-bearing ones, are partially reduced in human blood. Reduction leads to pronounced conformational changes within C4 that considerably affect the accessibility of the integrin-binding motif, and thereby impair integrin-mediated platelet binding. We also reveal that reduced species in the C4 domain undergo specific thiol/disulfide exchanges with the remaining disulfide bridges, in a process in which mechanical force may increase the proximity of specific reactant cysteines, further trapping C4 in a state of low integrin-binding propensity. We identify a multitude of redox states in all 6 VWF-C domains, suggesting disulfide bond reduction and swapping to be a general theme. Conclusions Our data suggests a mechanism in which disulfide bonds dynamically swap cysteine partners and control the interaction of VWF with integrin and potentially other partners, thereby critically influencing its hemostatic function

    AVALIAÇÃO DA ATIVIDADE BACTERICIDA DE DESINFETANTES COMERCIAIS EM AMOSTRAS BACTERIANAS ISOLADAS DE BANHEIROS PÚBLICOS

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    A contaminação por microrganismos patogênicos pode estar relacionada com o contato com superfícies inanimadas como vasos sanitários. Diante dessa realidade, o presente estudo teve como objetivo avaliar a atividade bactericida de cinco desinfetantes comerciais (o-benzil p-clorofenol 0,9%, quaternário de amônio - 0,45%, 0,30%, 0,28% e 0,25%), comparado a bactérias isoladas de vasos sanitários públicos. As amostras bacterianas foram coletadas usando a técnica com swabs e coradas pela coloração de Gram. Das amostras isoladas E. coli, Proteus e Staphylococcus sp. foram escolhidas para os demais testes. Foram realizados testes de esterilidade dos desinfetantes utilizando os meios MacConkey e Muller-Hinton a fim de evitar resultados não confiáveis. As atividades bactericidas de desinfetantes estéreis foram avaliadas frente as bactérias escolhidas. Os resultados mostraram que o princípio ativo a benzil - p - clorofenol 0,9% obteve eficácia contra os três microrganismos, ao passo que o princípio ativo de quaternário de amônia, em diferentes concentrações foi eficaz em algumas bactérias, mas que foi diminuindo a sua atividade durante o período de 21 dias
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