708 research outputs found

    Surgical solutions for complex aortic root pathology

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    Patients, from neonates to elderly, in need of aortic root replacement have several surgical options for their problem. This thesis describes the outcomes after aortic root replacement with biological prostheses, focusing on the pulmonary autograft (Ross procedure) and a stentless porcine aortic root prosthesis. These outcomes can be used to inform patients, cardiologists and cardiac surgeons in the shared decision making process of prosthesis choice.LUMC / Geneeskund

    Where Next for Formal Methods?

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    Prime ideals in nilpotent Iwasawa algebras

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    Let G be a nilpotent complete p-valued group of finite rank and let k be a field of characteristic p. We prove that every faithful prime ideal of the Iwasawa algebra kG is controlled by the centre of G, and use this to show that the prime spectrum of kG is a disjoint union of commutative strata. We also show that every prime ideal of kG is completely prime. The key ingredient in the proof is the construction of a non-commutative valuation on certain filtered simple Artinian rings

    A High Density of Human Communication-Associated Genes in Chromosome 7q31-q36: Differential Expression in Human and Non-Human Primate Cortices

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    The human brain is distinguished by its remarkable size, high energy consumption, and cognitive abilities compared to all other mammals and non-human primates. However, little is known about what has accelerated brain evolution in the human lineage. One possible explanation is that the appearance of advanced communication skills and language has been a driving force of human brain development. The phenotypic adaptations in brain structure and function which occurred on the way to modern humans may be associated with specific molecular signatures in today’s human genome and/or transcriptome. Genes that have been linked to language, reading, and/or autism spectrum disorders are prime candidates when searching for genes for human-specific communication abilities. The database and genome-wide expression analyses we present here revealed a clustering of such communication-associated genes (COAG) on human chromosomes X and 7, in particular chromosome 7q31-q36. Compared to the rest of the genome, we found a high number of COAG to be differentially expressed in the cortices of humans and non-human primates (chimpanzee, baboon, and/or marmoset). The role of X-linked genes for the development of human-specific cognitive abilities is well known. We now propose that chromosome 7q31-q36 also represents a hot spot for the evolution of human-specific communication abilities. Selective pressure on the T cell receptor beta locus on chromosome 7q34, which plays a pivotal role in the immune system, could have led to rapid dissemination of positive gene variants in hitchhiking COAG

    Assembly and covalent cross-linking of an amine-functionalised metal-organic cage

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    The incorporation of reactive functional groups onto the exterior of metal-organic cages (MOCs) opens up new opportunities to link their well-defined scaffolds into functional porous solids. Amine moieties offer access to a rich catalogue of covalent chemistry; however, they also tend to coordinate undesirably and interfere with MOC formation, particular in the case of Cu2 paddlewheel-based MOCs. We demonstrate that tuning the basicity of an aniline-functionalized ligand enables the self-assembly of a soluble, amine-functionalized Cu4L4 lantern cage (1). Importantly, we show control over the coordinative propensity of the exterior amine of the ligand, which enables us to isolate a crystalline, two-dimensional metal-organic framework composed entirely of MOC units (2). Furthermore, we show that the nucleophilicity of the exterior amine of 1 can be accessed in solution to generate a cross-linked cage polymer (3) via imine condensation.Matthew L. Schneider, Adrian W. Markwell-Heys, Oliver M. Linder-Patton and Witold M. Bloc

    Photosensitivity in South Africa. III. Ovine hepatogenous photosensitivity caused by the plant Athanasia trifurcata L. (Asteraceae)

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    Hepatogenous photosensitivity was experimentally induced in 1 out of 4 sheep dosed with milled Athanasia trifurcata. This is an unpalatable aromatic shrub commonly found along the south-western and south-eastern Cape coast on overgrazed, recently burnt or disturbed veld, up to an altitude of 1100 m. The liver lesions ranged from a few small multifocal areas of necrosis in 1 animal to various zonal patterns of necrosis (centrizonal, midzonal and peripheral) in each of the other 3. Botanical, toxicological and clinical data are given.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

    The Galactic Halo in Mixed Dark Matter Cosmologies

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    A possible solution to the small scale problems of the cold dark matter (CDM) scenario is that the dark matter consists of two components, a cold and a warm one. We perform a set of high resolution simulations of the Milky Way halo varying the mass of the WDM particle (mWDMm_{\rm WDM}) and the cosmic dark matter mass fraction in the WDM component (fˉW\bar{f}_{\rm W}). The scaling ansatz introduced in combined analysis of LHC and astroparticle searches postulates that the relative contribution of each dark matter component is the same locally as on average in the Universe (e.g. fW,=fˉWf_{\rm W,\odot} = \bar{f}_{\rm W}). Here we find however, that the normalised local WDM fraction (fW,f_{\rm W,\odot} / fˉW\bar{f}_{\rm W}) depends strongly on mWDMm_{\rm WDM} for mWDM<m_{\rm WDM} < 1 keV. Using the scaling ansatz can therefore introduce significant errors into the interpretation of dark matter searches. To correct this issue a simple formula that fits the local dark matter densities of each component is provided.Comment: 19 pages, 10 figures, accepted for publication in JCA

    Methylation and Expression Analyses of the 7q Autism Susceptibility Locus Genes MEST, COPG2, and TSGA14 in Human and Anthropoid Primate Cortices

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    The autism susceptibility locus on human chromosome 7q32 contains the maternally imprinted MEST and the non-imprinted COPG2 and TSGA14 genes. Autism is a disorder of the ‘social brain’ that has been proposed to be due to an overbalance of paternally expressed genes. To study regulation of the 7q32 locus during anthropoid primate evolution, we analyzed the methylation and expression patterns of MEST, COPG2, and TSGA14 in human, chimpanzee, Old World monkey (baboon and rhesus macaque), and New World monkey (marmoset) cortices. In all human and anthropoid primate cortices, the MEST promoter was hemimethylated, as expected for a differentially methylated imprinting control region, whereas the COPG2 and TSGA14 promoters were completely demethylated, typical for transcriptionally active non-imprinted genes. The MEST gene also showed comparable mRNA expression levels in all analyzed species. In contrast, COPG2 expression was downregulated in the human cortex compared to chimpanzee, Old and New World monkeys. TSGA14 either showed no differential regulation in the human brain compared to chimpanzee and marmoset or a slight upregulation compared to baboon. The human-specific downregulation supports a role for COPG2 in the development of a ‘social brain’. Promoter methylation patterns appear to be more stable during evolution than gene expression patterns, suggesting that other mechanisms may be more important for inter-primate differences in gene expression

    Timed patterns: TCOZ to timed automata

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    Abstract. The integrated logic-based modeling language, Timed Communicating Object Z (TCOZ), is well suited for presenting complete and coherent requirement models for complex real-time systems. However, the challenge is how to verify the TCOZ models with tool support, especially for analyzing timing properties. Specialized graph-based modeling technique, Timed Automata (TA), has powerful mechanisms for designing real-time models using multiple clocks and has well developed automatic tool support. One weakness of TA is the lack of high level composable graphical patterns to support systematic designs for complex systems. The investigation of possible links between TCOZ and TA may benefit both techniques. For TCOZ, TA’s tool support can be reused to check timing properties. For TA, a set of composable graphical patterns can be defined based on the semantics of the TCOZ constructs, so that those patterns can be re-used in a generic way. This paper firstly defines the composable TA graphical patterns, and then presents sound transformation rules and a tool for projecting TCOZ specifications into TA. A case study of a railroad crossing system is demonstrated

    Exploiting magnification bias in ultradeep submillimetre-wave surveys using ALMA

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    The surface density of populations of galaxies with steep/shallow source counts is increased/decreased by gravitational lensing magnification. These effects are usually called `magnification bias' and `depletion' respectively. However, if sources are demagnified by lensing, then the situation is reversed, and the detectable surface density of galaxies with a shallow source count, as expected at the faintest flux densities, is increased. In general, demagnified sources are difficult to detect and study: exquisite subarcsecond angular resolution and surface brightness sensitivity are required, and emission from the lensing object must not dominate the image. These unusual conditions are expected to be satisfied for observations of the dense swarm of demagnified images that could form very close to the line of sight through the centre of a rich cluster of galaxies using the forthcoming submillimetre-wave Atacama Large Millimeter Array (ALMA) interferometer. The demagnified images of most of the background galaes lying within about 1 arcmin of a rich cluster of galaxies could be detected in a single 18-arcsec-diameter ALMA field centred on the cluster core, providing an effective increase in the ALMA field of view. This technique could allow a representative sample of faint, 10-100 microJy submillimetre galaxies to be detected several times more rapidly than in a blank field.Comment: 6 pages, 2 figures, MNRAS in pres
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