655 research outputs found
High Energy Heavy Ion-Induced Structural Modifications in Binary Oxides.
The objective of this work was to determine the relation between materials properties and their effect on the structural response of binary oxides to high energy heavy ion irradiation. The Group 14 oxides offered an ideal system of study due to the gradual change in materials properties from SiO2 to PbO2, while their electronic configurations remain consistent; this series facilitated the association of specific materials properties with their effect on radiation response. SnO2 and PbO2 were investigated experimentally in order to complete the body of data for this system. For comparative purposes, Ta2O5 was investigated under the same conditions due to the contrast in physical and chemical characteristics it offers, as well as its unusually large and complicated unit cell. SnO2, PbO2, and Ta2O5 were irradiated by 2.2 GeV 197Au ions (11.1 MeV/u) at room temperature. Samples were analyzed with synchrotron X-ray diffraction, Raman spectroscopy, transmission electron microscopy, small-angle X-ray scattering, and X-ray photoelectron spectroscopy.
Irradiation of SnO2 led to the formation of a crystalline SnO phase with trace quantities of metallic Sn, indicating the loss of oxygen and cation reduction during irradiation. Irradiation of PbO2 resulted in the formation of seven distinct structures with compositions of Pb2O3, Pb3O4, PbO, and Pb. Gradual cation reduction was measured. Irradiation of Ta2O5 induced amorphous ion tracks with core-shell morphologies. Oxygen loss was evidenced, increasing with fluence to an estimated final stoichiometry of Ta2O4.2.
Using the Group 14 oxide system, the following relations were made: (i) increased susceptibility to amorphization has been attributed to high enthalpy of formation, bandgap, electrical resistivity, and cation electronegativity (relative to those resistant to amorphization), as well as relatively low bond ionicity and bond lengths; (ii) increased susceptibility to oxygen loss during irradiation has been attributed to relatively low bond dissociation energy, bandgap, and electrical resistivity, as well as relatively large bond lengths; (iii) increased susceptibility to cation reduction has been attributed to relatively high bond ionicity as well as low enthalpy of formation, melting temperature, resistivity, and cation electronegativity. Materials property value thresholds are presented for all properties that show correlations to each radiation effect.PhDMaterials Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113452/1/acusick_1.pd
Capacitive Deionization -- defining a class of desalination technologies
Over the past decade, capacitive deionization (CDI) has realized a surge in
attention in the field of water desalination and can now be considered as an
important technology class, along with reverse osmosis and electrodialysis.
While many of the recently developed technologies no longer use a mechanism
that follows the strict definition of the term "capacitive", these methods
nevertheless share many common elements that encourage treating them with
similar metrics and analyses. Specifically, they all involve electrically
driven removal of ions from a feed stream, storage in an electrode (i.e., ion
electrosorption) and release, in charge/discharge cycles. Grouping all these
methods in the technology class of CDI makes it possible to treat evolving new
technologies in standardized terms and compare them to other technologies in
the same class
Hydroxychloroquine: A Comprehensive Review and Its Controversial Role in Coronavirus Disease 2019
Hydroxychloroquine, initially used as an antimalarial, is used as an immunomodulatory and anti-inflammatory agent for the management of autoimmune and rheumatic diseases such as systemic lupus erythematosus. Lately, there has been interest in its potential efficacy against severe acute respiratory syndrome coronavirus 2, with several speculated mechanisms. The purpose of this review is to elaborate on the mechanisms surrounding hydroxychloroquine. The review is an in-depth analysis of the antimalarial, immunomodulatory, and antiviral mechanisms of hydroxychloroquine, with detailed and novel pictorial explanations. The mechanisms of hydroxychloroquine are related to potential cardiotoxic manifestations and demonstrate potential adverse effects when used for coronavirus disease 2019 (COVID-19). Finally, current literature associated with hydroxychloroquine and COVID-19 has been analyzed to interrelate the mechanisms, adverse effects, and use of hydroxychloroquine in the current pandemic. Currently, there is insufficient evidence about the efficacy and safety of hydroxychloroquine in COVID-19.KEY MESSAGES HCQ, initially an antimalarial agent, is used as an immunomodulatory agent for managing several autoimmune diseases, for which its efficacy is linked to inhibiting lysosomal antigen processing, MHC-II antigen presentation, and TLR functions. HCQ is generally well-tolerated although severe life-threatening adverse effects including cardiomyopathy and conduction defects have been reported. HCQ use in COVID-19 should be discouraged outside clinical trials under strict medical supervision
Protein–Protein Interactions Essentials: Key Concepts to Building and Analyzing Interactome Networks
8 páginas, 3 figuras, 1 tabla.-- This is an open-access article distributed under the terms of the Creative Commons Attribution License.This work has been supported by funds provided by the Local Government Junta de Castilla y León (JCyL, ref. project: CSI07A09), by the Spanish Ministry of Science and Innovation (MICINN - ISCiii, ref. projects: PI061153 and PS09/00843) and by the European Commission Research Grant PSIMEx (ref. FP7-HEALTH-2007-223411).Peer Reviewe
A UK wide cohort study describing management and outcomes for infants with surgical Necrotising Enterocolitis
The Royal College of Surgeons have proposed using outcomes from necrotising enterocolitis (NEC) surgery for revalidation of neonatal surgeons. The aim of this study was therefore to calculate the number of infants in the UK/Ireland with surgical NEC and describe outcomes that could be used for national benchmarking and counselling of parents. A prospective nationwide cohort study of every infant requiring surgical intervention for NEC in the UK was conducted between 01/03/13 and 28/02/14. Primary outcome was mortality at 28-days. Secondary outcomes included discharge, post-operative complication, and TPN requirement. 236 infants were included, 43(18%) of whom died, and eight(3%) of whom were discharged prior to 28-days post decision to intervene surgically. Sixty infants who underwent laparotomy (27%) experienced a complication, and 67(35%) of those who were alive at 28 days were parenteral nutrition free. Following multi-variable modelling, presence of a non-cardiac congenital anomaly (aOR 5.17, 95% CI 1.9-14.1), abdominal wall erythema or discolouration at presentation (aOR 2.51, 95% CI 1.23-5.1), diagnosis of single intestinal perforation at laparotomy (aOR 3.1 95% CI 1.05-9.3), and necessity to perform a clip and drop procedure (aOR 30, 95% CI 3.9-237) were associated with increased 28-day mortality. These results can be used for national benchmarking and counselling of parents
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The diminished effect of index rebalances
The author revisits the strategy of trading S&P 500 index re-compositions under the pre- and post-crisis financial environments, proving that the return structure has
significantly changed. The results show for the first time, that there are currently no tradable abnormal returns between announcement and event dates in the post-crisis
sample period, indicating smoother rebalancing mechanisms by bank’s client facing desks and better services for passive end-investors. The newly added firms inflate the
S&P 500 index by less than 10 basis points per year. The results could be attributed to improved execution algorithms used by the banks, and potentially to the new
regulatory reforms in the sector, which prevents financial institutions from taking large trading positions with their balance sheets
Literature curation of protein interactions: measuring agreement across major public databases
Literature curation of protein interaction data faces a number of challenges. Although curators increasingly adhere to standard data representations, the data that various databases actually record from the same published information may differ significantly. Some of the reasons underlying these differences are well known, but their global impact on the interactions collectively curated by major public databases has not been evaluated. Here we quantify the agreement between curated interactions from 15 471 publications shared across nine major public databases. Results show that on average, two databases fully agree on 42% of the interactions and 62% of the proteins curated from the same publication. Furthermore, a sizable fraction of the measured differences can be attributed to divergent assignments of organism or splice isoforms, different organism focus and alternative representations of multi-protein complexes. Our findings highlight the impact of divergent curation policies across databases, and should be relevant to both curators and data consumers interested in analyzing protein-interaction data generated by the scientific community
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From silence to primary definer: The rise of the Intelligence lobby in the public sphere
Until the end of the Cold War the UK intelligence services were not officially acknowledged, and their personnel were banned from entering the public sphere. From 1989 the UK government began to put the intelligence services on a legal footing and to release the identity of the heads of the intelligence agencies. Since then, public engagement by the intelligence agencies has gathered pace. What this article hypothesises is that there is now, in the UK, an effective intelligence lobby of former insiders who engage in the public sphere – using on the record briefings – to counter criticism of the intelligence community and to promote a narrative and vision of what UK intelligence should do, how it is supported and how oversight is conducted. Content analysis and framing models of non-broadcast coverage of intelligence debates, focusing on the 36 months after the Snowden revelations, confirm an active and rolling lobby of current and former intelligence officials. The paper concludes that the extent of the lobby’s interventions in the public sphere is a matter for debate and possible concern
Markov clustering versus affinity propagation for the partitioning of protein interaction graphs
<p>Abstract</p> <p>Background</p> <p>Genome scale data on protein interactions are generally represented as large networks, or graphs, where hundreds or thousands of proteins are linked to one another. Since proteins tend to function in groups, or complexes, an important goal has been to reliably identify protein complexes from these graphs. This task is commonly executed using clustering procedures, which aim at detecting densely connected regions within the interaction graphs. There exists a wealth of clustering algorithms, some of which have been applied to this problem. One of the most successful clustering procedures in this context has been the Markov Cluster algorithm (MCL), which was recently shown to outperform a number of other procedures, some of which were specifically designed for partitioning protein interactions graphs. A novel promising clustering procedure termed Affinity Propagation (AP) was recently shown to be particularly effective, and much faster than other methods for a variety of problems, but has not yet been applied to partition protein interaction graphs.</p> <p>Results</p> <p>In this work we compare the performance of the Affinity Propagation (AP) and Markov Clustering (MCL) procedures. To this end we derive an unweighted network of protein-protein interactions from a set of 408 protein complexes from <it>S. cervisiae </it>hand curated in-house, and evaluate the performance of the two clustering algorithms in recalling the annotated complexes. In doing so the parameter space of each algorithm is sampled in order to select optimal values for these parameters, and the robustness of the algorithms is assessed by quantifying the level of complex recall as interactions are randomly added or removed to the network to simulate noise. To evaluate the performance on a weighted protein interaction graph, we also apply the two algorithms to the consolidated protein interaction network of <it>S. cerevisiae</it>, derived from genome scale purification experiments and to versions of this network in which varying proportions of the links have been randomly shuffled.</p> <p>Conclusion</p> <p>Our analysis shows that the MCL procedure is significantly more tolerant to noise and behaves more robustly than the AP algorithm. The advantage of MCL over AP is dramatic for unweighted protein interaction graphs, as AP displays severe convergence problems on the majority of the unweighted graph versions that we tested, whereas MCL continues to identify meaningful clusters, albeit fewer of them, as the level of noise in the graph increases. MCL thus remains the method of choice for identifying protein complexes from binary interaction networks.</p
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