256 research outputs found

    Classification of one-dimensional quasilattices into mutual local-derivability classes

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    One-dimensional quasilattices are classified into mutual local-derivability (MLD) classes on the basis of geometrical and number-theoretical considerations. Most quasilattices are ternary, and there exist an infinite number of MLD classes. Every MLD class has a finite number of quasilattices with inflation symmetries. We can choose one of them as the representative of the MLD class, and other members are given as decorations of the representative. Several MLD classes of particular importance are listed. The symmetry-preserving decorations rules are investigated extensively.Comment: 42 pages, latex, 5 eps figures, Published in JPS

    Quartz crystal reinforced silica glass obtained by Spark plasma sintering

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    Spark Plasma Sintering (SPS) presents a very low processing time when compared to conventional sintering methods. Such fast processing conditions allow it to control the grain size growth and preserve the powders distribution into the mold during sintering, which makes it possible to obtain graded and nano structured (using nano-powders) materials. High purity powders of vitreous silica and crystalline silica (alpha quartz) were sintered by the SPS process at temperature of 1350°C, which is higher than the annealing temperature of vitreous silica and below the temperature of quartz fusion. Such investigation showed the possibility to obtain high purity SiO2 material, which is a composite of silica glass matrix reinforced with crystalline alpha-quartz powder at almost any combination of volume fraction of matrix/reinforced structure, with well controlled reinforced grain size. X-ray diffraction and density measurements show the possibility to manufacture a unique glass-ceramic material of controlled crystallinity and density.CAPE

    The pseudo‐brookite spin‐glass system studied by means of muon spin relaxation

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    Zero-field muon spin relaxation (”SR) experiments have been performed on the spin glass Fe1.75Ti1.25O5. Above the spin-glass temperature of 44 K a distinct exponential ”SR rate (Âż) is observed, while below Tg a square-root exponential decay occurs, indicating fast spin fluctuations. Near 8 K, a maximum in Âż is indicative of transverse spin ordering. The low Âż values and the sharp Âż peak at Tg are very promising for the study of spin freezing models like the Vogel–Fulcher law or the power law

    A Uniform Genomic Minor Histocompatibility Antigen Typing Methodology and Database Designed to Facilitate Clinical Applications

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    BACKGROUND: Minor Histocompatibility (H) antigen mismatches significantly influence the outcome of HLA-matched allogeneic stem cell transplantation. The molecular identification of human H antigens is increasing rapidly. In parallel, clinical application of minor H antigen typing has gained interest. So far, relevant and simple tools to analyze the minor H antigens in a quick and reliable way are lacking. METHODOLOGY AND FINDINGS: We developed a uniform PCR with sequence-specific primers (PCR-SSP) for 10 different autosomal minor H antigens and H-Y. This genomic minor H antigen typing methodology allows easy incorporation in the routine HLA typing procedures. DNA from previously typed EBV-LCL was used to validate the methodology. To facilitate easy interpretation for clinical purposes, a minor H database named dbMinor (http://www.lumc.nl/dbminor) was developed. Input of the minor H antigen typing results subsequently provides all relevant information for a given patient/donor pair and additional information on the putative graft-versus-host, graft-versus-tumor and host-versus-graft reactivities. SIGNIFICANCE: A simple, uniform and rapid methodology was developed enabling determination of minor H antigen genotypes of all currently identified minor H antigens. A dbMinor database was developed to interpret the genomic typing for its potential clinical relevance. The combination of the minor H antigen genomic typing methodology with the online dbMinor database and applications facilitates the clinical application of minor H antigens anti-tumor targets after stem cell transplantation
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