196,083 research outputs found

    Single‐stranded‐DNA‐binding proteins from human mitochondria and Escherichia coli have analogous physicochemical properties

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    The gene for the mature human mitochondrial single‐stranded‐DNA binding protein (HsmtSSB) has been transferred into a protein‐overproducing vector and expressed in Escherichia coli. The protein was purified to homogeneity and its physicochemical properties were investigated. From sequence comparison, HsmtSSB shows some similarities to the N‐terminal part of the single‐stranded DNA‐binding protein (SSB) from E. coli (EcoSSB). Hydrodynamic measurements show the protein to be tetrameric and give a sedimentation coefficient of 4.1 S corresponding to a C‐terminally shortened EcoSSB. Electron‐microscopic images of the free protein show a globular tetrahedral structure. Binding of poly(desoxythymidylic acid) [poly(dT)] leads to a reduction of the tryptophan fluorescence of the protein up to 96%. Fluorescence titrations with poly(dT) show apparent binding‐site sizes of 50–70 nucleotides/tetramer between 0.05 M and 2 M NaCl. Binding to poly(dT) proceeds in a nearly diffusion‐controlled reaction with an association‐rate constant kass of 4 · 108 M−1S−1. The rate‐limiting step is the formation of a transient complex where less than four binding sites on the protein are involved and the reshuffling of the protein of the protein on the linear matrix is fast. Electron microscopy of the complex with poly(dT) using negative staining shows a nearly random distribution of the protein between the individual poly(dT) strands. This leads to the conclusion that the binding cooperativity is low (ω < 150). The two tryptophans of HsmtSSB were replaced by threonine and tyrosine. The environment of both residues is influenced by nucleic acid binding with mutations of Trp68 strongly reducing the DNA‐binding affinity of the protein. Copyright © 1994, Wiley Blackwell. All rights reserve

    Evidence Against Keratin Gene Mutations in a Family with Ichthyosis Hystrix Curth-Macklin

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    Ichthyosis hystrix Curth-Macklin is a rare autosomal dominant disease characterized clinically by hyperkeratosis and ultrastructurally by disruption of the keratin intermediate filament network of suprabasal keratinocytes. We have used linkage analysis to test whether a keratin gene mutation might underlie this disease. This analysis excluded the keratin gene loci as the sites for the disease-causing mutation in one affected kindred

    Dr. Duane M. Jackson, Morehouse College, July 2011

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    This video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer

    "Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.

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    "Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states. By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement. To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports

    Dispelling the Myths Behind First-author Citation Counts

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    We conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more sophisticated methods

    Dr. Glendon Swarthout

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    Hosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness

    Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses

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    Following an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied

    Intern experience at CH���M Hill, Inc.: an internship report

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    Includes author's vita"Submitted to the College of Engineering of Texas A&M University in partial fulfillment of the requirement for the degree of Doctor of Engineering."Includes bibliographical referencesA review of the author's internship experience with CH���M HILL, Inc. during the period September 1975 through May 1976 is presented. During this nine month internship the author worked as an Engineer II in the Industrial Processes discipline of this large consulting engineering firm... The author's prime responsibility was as one of three lead design engineers on the design of a large wastewater treatment facility for a pulp mill in Hoquiam, Washington owned by ITT Rayonier Inc. The work generally consisted of the design of individual treatment units and associated piping and pumping. The purpose of the project was to provide wastewater treatment capabilities that would satisfy the effluent limitations (standards) imposed upon the mill by the State of Washington Department of Ecology and the U.S. Environmental Protection Agency. The author's assignment also entailed necessary interaction with the project manager and other CH���M HILL design engineers and support staff members, the client's representatives, and representatives of two other consulting engineering firms working on the project. Thus, the internship position at CH���M HILL provided considerable experience coordinating the author's work with the work of other engineers, guiding the design and administrative efforts of a support staff, and interacting regularly with the client and other consulting firms. This broad exposure to a variety of engineering and organizational problems provided a valuable educational experience

    Role of the keratin 1 and keratin 10 tails in the pathogenesis of ichthyosis hystrix of Curth Macklin

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    Ichthyosis Hystrix of Curth-Macklin (IH-CM) is a rare manifestation of epidermolytic ichthyosis (EI) that is characterised by generalised spiky or verrucous hyperkeratosis. The disorder is further distinguished by the presence of binucleated cells in the affected skin, whereas epidermolysis and clumping of tonofilaments, as seen in EI, are absent. While IH-CM is associated with mutations in the keratin 1 (KRT1) gene, reports to date have indicated that mutations in the KRT1 gene result in an aberrant and truncated protein tail, essentially affecting the function of the V2 domain. Here, we studied a female sporadic patient who was born with diffused erythrodermic hyperkeratosis and who presented at the age of 13 months with an intense and widespread hyperkeratosis with a papillomatous appearance and typical palmoplantar keratoderma. Genetic analysis demonstrated a “de novo” mutation in the keratin 10 gene (KRT10) consisting of a three-base-pair deletion, resulting in the substitution of amino acids p.Glu445 and p.Ile446 by Asp at the end of the 2B domain of the protein. We performed structural and functional studies showing that this mutation modifies the structure of the paired 2B and V2 K1/10 domains, leading to the disease phenotype. Our results highlight the importance and complexity of the KRT1/10 V2 domain in keratin dimer formation and the potential consequences of its alteration.</div

    Transition to turbulence in a qblique shock-wave/boundary-layer interaction at M=15

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    Direct numerical simulations are carried out for different forcing techniques to trigger transition during the interaction between an oblique shock-wave and a laminar boundary-layer at M = 1.5. Three forcing methods are used: a) forcing of oblique unstable modes, whose shape and behaviour are determined by the local linear stability theory, b) broadband free-stream acoustic disturbances, and c) a cold plasma flow control device. While the oblique-mode breakdown is dominant for low-amplitude forcing, long streaky structures drive the transition process in a high-amplitude disturbance environment. LES are also performed on the experimental setup by the Institute of Theoretical and Applied Mechanics (ITAM) from Novosibirsk State University with cold plasma actuation. As well as the disturbance type, the effect of Reynolds number and forcing amplitude will be investigated
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