2,878 research outputs found
Liquid structure of Rb-Hg alloys studied by neutron diffraction
No full textThe structures of liquid Rb–Hg alloys were studied as a function of composition by neutron diffraction. In the intermediate Rb concentration range, the obtained structure factors show a small prepeak, which may be an evidence of the formation of Hg polyanion units in liquids. The Reverse Monte Carlo (RMC) analysis was applied to separate the total radial distribution function into the corresponding partial radial distribution functions. Up to 10 at.% Rb, no obvious changes are found for the first peak position of the partial radial distribution functions of the Hg–Hg pair and that of the Hg–Rb pair. The first peak position between the Hg–Rb pairs increases above 20 at.% Rb. In addition to the first peak, a subpeak between Hg–Hg pairs can be seen in the large distance. At 60 at.% Rb, the nearest neighbor distance between Hg atoms shows the closest value in the concentration range studied. These results indicate that with the progress of charge transfer the solvation structure in the dilute Rb concentration range changes into the structure containing polyanions composed of Hg species
Fractional Edge Cover Number of Model RB
No full textModel RB is a random constraint satisfaction problem with a growing domain size, which exhibits exact phase transition phenomena. Many hard instances with planted solutions can be generated via Model RB, to be used as benchmarks for algorithmic competitions and researches. In the past, some structural parameters of constraint hypergraphs are analyzed to show hardness of Model RB, such as hinge width, decycling number, treewidth, and hypertree width. In this paper, one more structural parameter of constraint hypergraphs of Model RB, namely the fractional edge cover number, is analyzed. We show upper and lower bounds on the fractional edge cover number of Model RB. In particular, the fractional edge cover number of Model RB is shown to be asymptotically linear in the number of variables, like hinge width, decycling number, treewidth and hypertree width. These results together provide further evidences on the hardness of Model RB.EICPCI-S(ISTP)[email protected]
There is no evidence of an association in children and teenagers between the apolipoprotein E epsilon4 allele and post-traumatic brain swelling
No full textTraumatic brain injury (TBI) is an important cause of mortality and disability in children and teenagers. A particular feature of the neuropathology at post-mortem is brain swelling. The cause of the swelling in some cases is not known, while in others it is associated with traumatic axonal injury or hypoxia. Apolipoprotein E (APOE) 4 allele is known to be an important genetic determinant of outcome in children after TBI. We hypothesized a relationship between possession of APOE4 and diffuse traumatic brain swelling. A total of 165 cases aged between 2 and 19 years were identified from the department's tissue archive. APOE genotype was determined by polymerase chain reaction (PCR) in 106 cases. Bilateral swelling was present in 44 cases (11 with APOE4), unilateral swelling in 25 cases (7 with APOE4) and in 36 cases (9 with APOE4) there was no evidence of brain swelling. There was no significant relationship between possession of APOE4 and the presence of cerebral swelling (?2 = 0.09, df = 2, P = 0.96). The 95% confidence interval for difference in proportions with swelling in those with and without the APOE4 is ?19% to 22%. Thus, a significant relationship was not found between diffuse brain swelling and possession of APOE4, and in this cohort of patients there was an identifying cause of the brain swelling in all cases
No evidence for the presence of apolipoprotein epsilon-4, interleukin-1 alpha allele 2 and interleukin-1 beta allele 2 cause an increase in programmed cell death following traumatic brain injury in humans
No full textBackground: Brain injury after trauma is an important cause of mortality and morbidity in society. There is evidence in both man and laboratory animals that in addition to necrosis, cell loss may occur as a result of programmed cell death (PCD). The cellular and molecular responses after head injury are partly influenced by genetic polymorphisms of apolipoprotein E and the proinflammatory cytokine IL-1. Aim: The principal aim of this study was to determine whether the presence of the ApoE epsilon(4), IL-1(alpha 2) or IL-I beta(2) allele types influenced the amounts of PCD after head injury compared with controls. Methods: Paraffin sections from the hippocampus of 38 patients (32 M : 6 F, aged 15-75, mean 38 years, survival 7-576 hours; mean 36 hours) who died after a head injury were stained by Tunel histochemistry and quantified, and genotyping was undertaken by PCR "blind" to clinical detail. Results: There were more Tunel+ cells (neurons and glia) after head injury than in controls with statistically increased numbers in all sectors of the hippocampus including the dentate fascia. However, there was no correlation between ApoE epsilon(4), IL-1 alpha allele 2 and IL-1 beta allele 2 and the amount of Tunel positivity. Conclusion: Given that both the ApoE and IL-1 influence outcome after various forms of acute brain injury, further work will be required to determine the mechanism underlying this relationshi
MILLIMETER-WAVE SPECTROSCOPY OF COLD RB ATOMS
No full textAuthor Institution: Department of Physics, University of Virginia, McCormick Road, Charlottesville, Virginia 22903Cold Rb atoms were prepared by magneto-optical trap. Millimeter-wave has been used to drive nd to (n-2)f one-photon and nd to (n-1)g () two-photon transitions. Quantum defects of f and g states of Rb were calculated. Full analyses will be presented. }
Interpretation and the Problem of the Intention of the Author, by Burhanetir Tatar
No full textBurhanetir Tatar, Interpretation and the Problem of the Intention of the Author: H.G. Gadamer vs E.D. Hirsh, The Council for Research in Values and Philosophy, 199
Deletion of Rb Accelerates Pancreatic Carcinogenesis by Oncogenic Kras and Impairs Senescence in Pre-Malignant Lesions
No full textRb1 encodes a cell-cycle regulator that is functionally disrupted in most human cancers. Pancreatic ductal adenocarcinomas (PDACs) have a high frequency of mutations in KRAS and INK4A/CDKN2A that might allow cells to bypass the regulatory actions of retinoblastoma (RB). To determine the role of loss of RB function in PDAC progression, we investigated the effects of Rb disruption during pancreatic malignant transformation initiated by oncogenic Kras.We generated mice with pancreas-specific disruption of Rb, in the absence or presence of oncogenic Kras, to examine the role of RB in pancreatic carcinogenesis
An assessment of the differentiation potential of epithelial stem cells in adult endometrium
No full textBackground: We are at the beginning of a new era where regenerative medicine is really starting to take hold. An appreciation of adult stem cells and their role in tissue maintenance have heralded novel insight into endometrial remodelling. The idea that human endometrium could be a plentiful source of adult stem/progenitor cells (ASPCs) has captured the imagination of many stem cell biologists. Not only that, they are also hypothesised to be involved in endometrial proliferative diseases, such as endometriosis. However, work remains preliminary and is stunted by a lack of specific endometrial stem cell markers. Recently, stage specific embryonic antigen -1 (SSEA-1) was proposed as a candidate epithelial ASPC marker in adult endometrium. In order to validate this, stem cell assays are required. These assays include measurements of clonogenicity, prolonged self-renewal and differentiation potential.
Aim: To assess the differentiation potential of SSEA-1+ cells in vitro.
Methods: All endometrial culture samples were collected from pre-menopausal women undergoing surgery for benign disease at Liverpool Women’s Hospital (LWH). Epithelial cells were cultured in 3D MatrigelTM to produce gland-like structures. Gland-like structures were characterised via immuno-histochemistry, to validate their resemblance to glands in endometrial tissue in vivo. To assess multi-potency, magnetic cell sorted (MACS) SSEA-1 enriched and depleted cell fractions were cultured in adipogenic and osteogenic inducing media. In order to assess pluripotency, SSEA-1 enriched and depleted fractions were cultured in neurogenic media.
Results: SSEA-1 enriched cell fractions had a greater propensity to produce gland-like structures in 3D culture than SSEA-1 depleted cell fractions. Gland-like structures best resembled glands in post-menopausal (PM) endometrium. Non-gland like structures also formed in 3D culture from endometriosis samples, which stained exclusively and intensely for CK5/6. SSEA-1 enriched and depleted fractions were unable to differentiate into other cell types of mesodermal lineage. However, both enriched and depleted fractions were able to produce ectodermal derived neural-like PGP9.5 positive cells.
Discussion: This work confirms SSEA-1 is a reliable epithelial ASPC marker in adult endometrium. SSEA-1+ cells possess an increased ability to produce gland-like structures, reminiscent of in vivo endometrial glands. This therefore confirms unipotency. The presence of CK5/6 in non-gland-like structures from endometriosis samples suggests a potential role in endometriosis aetiology, and warrants further work. SSEA-1 enriched and depleted cells were unable to undergo multi-lineage differentiation, but were capable of producing neural-like cells. As both cell populations were unable to demonstrate multipotency, it unlikely SSEA-1 enriched/depleted cells are pluripotent. More likely, a neural progenitor may exist in adult endometrium, one that has been included in both cell populations. Given the close proximity of endometrial glands to the placenta, the commitment of epithelial stem cells could be an ancillary mechanism to prevent maternal microchimersim in offspring, which is associated with a number of pathologies
Aneuploidy in spermatids of Robertsonian (Rb) chromosome heterozygous mice
No full text© 2014, The Author(s). Rb translocations are chromosomal rearrangements frequently found in natural populations of the house mouse Mus musculus domesticus. The standard diploid karyotype of the house mouse consisting of 40 telocentric chromosomes may be reduced by the emergence of metacentric Rb chromosomes. Multiple simple Rb heterozygotes form trivalents exhibiting higher anaphase nondisjunction frequency and consequently higher number of unbalanced gametes than in normal males. This work will attempt to establish whether frequencies of aneuploidy observed in heterozygote spermatids of the house mouse M. musculus domesticus show differences in chromosomes derived from different trivalents. Towards this goal, the number and distribution frequency of aneuploidy was assessed via FISH staining of specific chromosomes of spermatids derived from 2n = 32 individuals. Our results showed that for a given set of target chromosomes, 90 % of the gametes were balanced, resulting from alternate s
Ear disease in Aboriginal and Torres Strait Islander children
No full textThis resource sheet reviews past and current programs, research and strategies (both government and non-government) for the prevention and treatment of ear disease in Indigenous children.
Introduction
Ear disease and the associated hearing loss are significant health problems for Indigenous children. Children in many Indigenous communities suffer from chronic ear disease, in particular otitis media, at rates that well exceed the 4% threshold at which a disease is regarded as a major public health problem. Ear disease, particularly where it leads to hearing loss, is a large contributor to poor educational achievement and higher unemployment and, as a consequence, greater contact with the criminal justice system later in life.
While the roots of this disease essentially lie in disadvantage and poverty, a number of environmental factors, individual genetics and microbial genomic factors also contribute. Preventing ear disease in Indigenous children by tackling these factors is a high priority.
While the social and biological bases of ear disease are reasonably well understood, many programs and strategies for its prevention do not appear to have worked effectively. In some cases, programs to prevent ear disease and associated hearing loss have been implemented without sufficient planning and high quality evidence. However, recent health services delivered under the Stronger Futures in the Northern Territory (SFNT) strategy have shown some success in reducing hearing loss, the prevalence of otitis media, and the severity of hearing impairment.
This resource sheet reviews past and current programs, research and strategies (both government and non-government) for the prevention and treatment of ear disease in Indigenous children. While the focus of the document is on preventing ear disease, programs aimed at treating infection and minimising hearing loss are also reviewed
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