1,106 research outputs found

    The splintered fragment

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    Nearly 20 years have now passed since critic Phillip Toynbee confidently but mistakenly assured readers of the London Observer that Lord of the Rings would soon be passing into “merciful oblivion.” The subsequent success these books have enjoyed has proven this prediction wholly unfounded. Far from fading into oblivion, The Lord of the Rings has found a very receptive audience among readers and critics of widely varying literary tastes, and while it is obviously too soon to suggest that the popularity it has enjoyed and the genius it displays will assure Tolkien a place among other great English writers like Chaucer and Milton, it seems certain that Tolkien will never fade into oblivion as Toynbee predicted in the summer of 1961. What seems equally certain is that his popularity will continue to grow as readers and critics read The Silmarillion, the collection of mythological tales about the earliest ages of Middle-Earth history, which forms the background for The Lord of the Rings

    Non-obstructive azoospermia and maturation arrest with complex translocation 46,XY t(9;13;14)(p22;q21.2;p13) is consistent with the Luciani-Guo hypothesis of latent aberrant autosomal regions and infertility

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    OBJECTIVE: To describe clinical and histological features observed in the setting of an unusual complex translocation involving three autosomes (9, 13, and 14) identified in an otherwise healthy male referred for infertility consultation. MATERIALS AND METHODS: The patient was age 30 and no family history was available (adopted). Total azoospermia was confirmed on multiple semen analyses. Peripheral karyotype showed a 46,XY t(9;13;14)(p22:q21.2;p13) genotype; no Y-chromosome microdeletions were identified. Cystic fibrosis screening was negative. Bilateral testis biopsy revealed uniform maturation arrest and peritubular fibrosis. RESULTS: Formal genetic counseling was obtained and the extant literature reviewed with the couple. Given the low probability of obtaining sperm on testicular biopsy, as well as the high risk of any retrieved sperm having an unbalanced genetic rearrangement, the couple elected to proceed with fertility treatment using anonymous donor sperm for insemination. CONCLUSION: Although genes mapped to the Y-chromosome have been established as critical to normal testicular development and spermatogenesis, certain autosomal genes are now also recognized as important in these processes. Here we present clinical evidence to support the Luciani-Guo hypothesis (first advanced in 1984 and refined in 2002), which predicts severe spermatogenic impairment with aberrations involving chromosomes 9, 13, and/or 14, independent of Y-chromosome status. Additional study including fluorescent in situ hybridization and molecular analysis of specific chromosomal regions is needed to characterize more fully the contribution(s) of these autosomes to male testicular development and spermatogenesis

    Inflammatory Markers Associated With Subclinical Coronary Artery Disease: The Multicenter AIDS Cohort Study.

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    BackgroundDespite evidence for higher risk of coronary artery disease among HIV+ individuals, the underlying mechanisms are not well understood. We investigated associations of inflammatory markers with subclinical coronary artery disease in 923 participants of the Multicenter AIDS Cohort Study (575 HIV+ and 348 HIV- men) who underwent noncontrast computed tomography scans for coronary artery calcification, the majority (n=692) also undergoing coronary computed tomography angiography.Methods and resultsOutcomes included presence and extent of coronary artery calcification, plus computed tomography angiography analysis of presence, composition, and extent of coronary plaques and severity of coronary stenosis. HIV+ men had significantly higher levels of interleukin-6 (IL-6), intercellular adhesion molecule-1, C-reactive protein, and soluble-tumor necrosis factor-α receptor (sTNFαR) I and II (all P<0.01) and a higher prevalence of noncalcified plaque (63% versus 54%, P=0.02) on computed tomography angiography. Among HIV+ men, for every SD increase in log-interleukin-6 and log intercellular adhesion molecule-1, there was a 30% and 60% increase, respectively, in the prevalence of coronary stenosis ≄50% (all P<0.05). Similarly, sTNFαR I and II in HIV+ participants were associated with an increase in prevalence of coronary stenosis ≄70% (P<0.05). Higher levels of interleukin-6, sTNFαR I, and sTNFαR II were also associated with greater coronary artery calcification score in HIV+ men (P<0.01).ConclusionsHigher inflammatory marker levels are associated with greater prevalence of coronary stenosis in HIV+ men. Our findings underscore the need for further study to elucidate the relationships of inflammatory pathways with coronary artery disease in HIV+ individuals

    Mapping the business systems of 61 major economies: a taxonomy and implications for varieties of capitalism and business systems research

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    Efforts to build a universal theory of the world’s business systems require empirical grounding in an understanding of the variety that need explaining. To support such theorizing, we analyzed the institutional structures of 61 major economies, accounting for 93.5% of 2013 world GDP at purchasing power parity. We found nine main types of business systems: Highly Coordinated, Coordinated Market, Liberal Market, European Peripheral, Advanced Emerging, Advanced City, Arab Oil-Based, Emerging, and Socialist Economies. Our findings illustrate the need to go beyond the Varieties of Capitalism and Business Systems frameworks; provide empirical support for the CME versus LME dichotomy for part of the OECD; identify some of the business systems proposed recently as sub-types of larger clusters; indicate that institutional diversity may increase with development level; and cast doubt on the notions of state-led and family-led capitalism as types of business systems. Our discussion further suggests numerous avenues for theory development and empirical research

    Trehalose Uptake through P2X7 Purinergic Channels Provides Dehydration Protection

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    The tetra-anionic form of ATP (ATP4-) is known to induce monovalent and divalent ion fluxes in cells that express purinergic P2X7 receptors (Steinberg et al., 1987; Sung et al., 1985), and with sustained application of ATP it has been shown that dyes as large as 831 daltons can permeate the cell membrane (Steinberg et al, 1987). The current study explores the kinetics of loading α,α-trehalose (342 daltons) into ATP stimulated J774.A1 cells, which are known to express the purinergic P2X7 receptor (Steinberg et al., 1987). Cells that were incubated at 37 ̊C in a 50 mM phosphate buffer (pH 7.0) contailing 225 mM trehalose and 5 mM ATP, were shown to load trehalose linearly over time. Concentrations of ~50 mM were reached within 90 min of incubation. Cells incubated in the same solution at 4 ̊C loaded minimally, consistent with the inactivity of the receptor at low temperatures. However, extended incubation at 37 oC (\u3e60 min) resulted in zero next-day survival, with adverse effects appearing even with incubation periods as short as 30 min. By using a two-step protocol with a short time period at 37 oC to allow pore formation, followed by an extended loading period on ice, cells could be loaded with up to 50 mM trehalose while maintaining good next day recovery (49% ± 12 % by Trypan Blue exclusion, 56 ± 20% by Alamar BlueTM assay). Cells porated by this method and allowed an overnight recovery period exhibited improved dehydration tolerance suggesting a role for ATP poration in the anhydrous preservation of cells

    Influence of Motor Planning on Distance Perception within the Peripersonal Space

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    We examined whether movement costs as defined by movement magnitude have an impact on distance perception in near space. In Experiment 1, participants were given a numerical cue regarding the amplitude of a hand movement to be carried out. Before the movement execution, the length of a visual distance had to be judged. These visual distances were judged to be larger, the larger the amplitude of the concurrently prepared hand movement was. In Experiment 2, in which numerical cues were merely memorized without concurrent movement planning, this general increase of distance with cue size was not observed. The results of these experiments indicate that visual perception of near space is specifically affected by the costs of planned hand movements

    The Role of Polycyclic Aromatic Hydrocarbons in Ultraviolet Extinction. I. Probing small molecular PAHs

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    We have obtained new STIS/HST spectra to search for structure in the ultraviolet interstellar extinction curve, with particular emphasis on a search for absorption features produced by polycyclic aromatic hydrocarbons (PAHs). The presence of these molecules in the interstellar medium has been postulated to explain the infrared emission features seen in the 3-13 ÎŒ\mum spectra of numerous sources. UV spectra are uniquely capable of identifying specific PAH molecules. We obtained high S/N UV spectra of stars which are significantly more reddened than those observed in previous studies. These data put limits on the role of small (30-50 carbon atoms) PAHs in UV extinction and call for further observations to probe the role of larger PAHs. PAHs are of importance because of their ubiquity and high abundance inferred from the infrared data and also because they may link the molecular and dust phases of the interstellar medium. A presence or absence of ultraviolet absorption bands due to PAHs could be a definitive test of this hypothesis. We should be able to detect a 20 \AA wide feature down to a 3σ\sigma limit of ∌\sim0.02 AV_V. No such absorption features are seen other than the well-known 2175 \AA bump.Comment: 16 pages, 3 figure, ApJ in pres
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