17 research outputs found

    X-ray scattering from warm dense iron

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    We have carried out X-ray scattering experiments on iron foil samples that have been compressed and heated using laser-driven shocks created with the VULCAN laser system at the Rutherford-Appleton Laboratory. This is the highest Z element studied in such experiments so far and the first time scattering from warm dense iron has been reported. Because of the importance of iron in telluric planets, the work is relevant to studies of warm dense matter in planetary interiors. We report scattering results as well as shock breakout results that, in conjunction with hydrodynamic simulations, suggest the target has been compressed to a molten state at several 100 GPa pressure. Initial comparison with modelling suggests more work is needed to understand the structure factor of warm dense iron

    Observations of continuum depression in warm dense matter with X-ray thomson scattering

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    Detailed measurements of the electron densities, temperatures, and ionization states of compressed CH shells approaching pressures of 50 Mbar are achieved with spectrally resolved x-ray scattering. Laser-produced 9 keV x-rays probe the plasma during the transient state of three-shock coalescence. High signal-to-noise x-ray scattering spectra show direct evidence of continuum depression in highly degenerate warm dense matter states with electron densities ne>1024cm-3. The measured densities and temperatures agree well with radiation-hydrodynamic modeling when accounting for continuum lowering in calculations that employ detailed configuration accounting

    Clinical and molecular characteristics of 1qter microdeletion syndrome: delineating a critical region for corpus callosum agenesis/hypogenesis.

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    Contains fulltext : 69539.pdf (publisher's version ) (Closed access)BACKGROUND: Patients with a microscopically visible deletion of the distal part of the long arm of chromosome 1 have a recognisable phenotype, including mental retardation, microcephaly, growth retardation, a distinct facial appearance and various midline defects including corpus callosum abnormalities, cardiac, gastro-oesophageal and urogenital defects, as well as various central nervous system anomalies. Patients with a submicroscopic, subtelomeric 1qter deletion have a similar phenotype, suggesting that the main phenotype of these patients is caused by haploinsufficiency of genes in this region. OBJECTIVE: To describe the clinical presentation of 13 new patients with a submicroscopic deletion of 1q43q44, of which nine were interstitial, and to report on the molecular characterisation of the deletion size. Results and CONCLUSIONS: The clinical presentation of these patients has clear similarities with previously reported cases with a terminal 1q deletion. Corpus callosum abnormalities were present in 10 of our patients. The AKT3 gene has been reported as an important candidate gene causing this abnormality. However, through detailed molecular analysis of the deletion sizes in our patient cohort, we were able to delineate the critical region for corpus callosum abnormalities to a 360 kb genomic segment which contains four possible candidate genes, but excluding the AKT3 gene

    Clinical and molecular delineation of the 17q21.31 microdeletion syndrome.

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    The chromosome 17q21.31 microdeletion syndrome is a novel genomic disorder that has originally been identified using high-resolution genome analyses in patients with unexplained mental retardation. Here we report the molecular and/or clinical characterization of 22 individuals with the 17q21.31 microdeletion syndrome. We estimate the prevalence of the syndrome to be 1 in 16,000 and show that it is highly underdiagnosed. Extensive clinical examination, reveals that developmental delay, hypotonia, facial dysmorphisms including a long face, a tubular or pear-shaped nose and a bulbous nasal tip, and a friendly/amiable behavior are the most characteristic features. Other clinically important features include epilepsy, heart defects (ASD, VSD), and kidney/ urologic anomalies. Using high-resolution oligonucleotide arrays, we narrow the 17q21.31 critical region to a 424-kb genomic segment (chr17: 41046729-41470954, hg17), encompassing at least six genes, among which the gene encoding microtubule-associated protein tau (MAPT). Mutation screening of MAPT in 122 individuals with a phenotype suggestive of 17q21.31 deletion carriers, but who do not carry the recurrent deletion, failed to identify any disease-associated variants. In five deletion carriers, we identify a <500-bp rearrangement hotspot at the proximal breakpoint contained within an L2 LINE motif and show that in every case examined, the parent originating the deletion carries a common 900-kb 17q21.31 inversion polymorphism, indicating that this inversion is a necessary factor for deletion to occur (p<10-5). Our data establishes the 17q21.31 microdeletion syndrome as a clinically and molecularly well recognizable genomic disorder
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