Indirect measurement of the viscosity of the intergranular glass phase in yttria-sintered silicon nitride

Dense, sintered Si3N4 possesses a residual intergranular glass phase which softens at high temperatures, resulting in degradation of the ceramic's mechanical properties at high temperatures. An important parameter in the determination of the high temperature mechanical properties of sintered Si3N4 is the temperature-viscosity relationship of the intergranular glass. A method for indirectly measuring the intergranular glass viscosity at a given temperature using physical modelling of a two phase glass crystal microstructure and beam bending viscometry measurements of Si3N4 is described. Intergranular glass viscosities obtained by this method are presented for a yttria sintered Si3N4

Iris: an Extensible Application for Building and Analyzing Spectral Energy Distributions

Iris is an extensible application that provides astronomers with a user-friendly interface capable of ingesting broad-band data from many different sources in order to build, explore, and model spectral energy distributions (SEDs). Iris takes advantage of the standards defined by the International Virtual Observatory Alliance, but hides the technicalities of such standards by implementing different layers of abstraction on top of them. Such intermediate layers provide hooks that users and developers can exploit in order to extend the capabilities provided by Iris. For instance, custom Python models can be combined in arbitrary ways with the Iris built-in models or with other custom functions. As such, Iris offers a platform for the development and integration of SED data, services, and applications, either from the user's system or from the web. In this paper we describe the built-in features provided by Iris for building and analyzing SEDs. We also explore in some detail the Iris framework and software development kit, showing how astronomers and software developers can plug their code into an integrated SED analysis environment.Comment: 18 pages, 8 figures, accepted for publication in Astronomy & Computin

Identification of antiviral roles for the exon-junction complex and nonsense-mediated decay in flaviviral infection.

West Nile virus (WNV) is an emerging mosquito-borne flavivirus, related to dengue virus and Zika virus. To gain insight into host pathways involved in WNV infection, we performed a systematic affinity-tag purification mass spectrometry (APMS) study to identify 259 WNV-interacting human proteins. RNA interference screening revealed 26 genes that both interact with WNV proteins and influence WNV infection. We found that WNV, dengue and Zika virus capsids interact with a conserved subset of proteins that impact infection. These include the exon-junction complex (EJC) recycling factor PYM1, which is antiviral against all three viruses. The EJC has roles in nonsense-mediated decay (NMD), and we found that both the EJC and NMD are antiviral and the EJC protein RBM8A directly binds WNV RNA. To counteract this, flavivirus infection inhibits NMD and the capsid-PYM1 interaction interferes with EJC protein function and localization. Depletion of PYM1 attenuates RBM8A binding to viral RNA, suggesting that WNV sequesters PYM1 to protect viral RNA from decay. Together, these data suggest a complex interplay between the virus and host in regulating NMD and the EJC

Fisetin protects against cardiac cell death through reduction of ROS production and caspases activity

Myocardial infarction (MI) is a leading cause of death worldwide. Reperfusion is considered as an optimal therapy following cardiac ischemia. However, the promotion of a rapid elevation of O2 levels in ischemic cells produces high amounts of reactive oxygen species (ROS) leading to myocardial tissue injury. This phenomenon is called ischemia reperfusion injury (IRI). We aimed at identifying new and effective compounds to treat MI and minimize IRI. We previously studied heart regeneration following myocardial injury in zebrafish and described each step of the regeneration process, from the day of injury until complete recovery, in terms of transcriptional responses. Here, we mined the data and performed a deep in silico analysis to identify drugs highly likely to induce cardiac regeneration. Fisetin was identified as the top candidate. We validated its effects in an in vitro model of MI/IRI in mammalian cardiac cells. Fisetin enhances viability of rat cardiomyocytes following hypoxia/starvation - reoxygenation. It inhibits apoptosis, decreases ROS generation and caspase activation and protects from DNA damage. Interestingly, fisetin also activates genes involved in cell proliferation. Fisetin is thus a highly promising candidate drug with clinical potential to protect from ischemic damage following MI and to overcome IRI.This work was supported by FNR, the Luxembourg National Research Fund, FNR-CORE INFUSED project. At the NorLux Laboratory and the Proteome and Genome Research Unit of LIH, it was also supported by funding from Luxembourg’s Ministry of Higher Education and Research (MESR).S

Managing Distributed Software Development in the Virtual Astronomical Observatory

The U.S. Virtual Astronomical Observatory (VAO) is a product-driven organization that provides new scientific research capabilities to the astronomical community. Software development for the VAO follows a lightweight framework that guides development of science applications and infrastructure. Challenges to be overcome include distributed development teams, part-time efforts, and highly constrained schedules. We describe the process we followed to conquer these challenges while developing Iris, the VAO application for analysis of 1-D astronomical spectral energy distributions (SEDs). Iris was successfully built and released in less than a year with a team distributed across four institutions. The project followed existing International Virtual Observatory Alliance inter-operability standards for spectral data and contributed a SED library as a by-product of the project. We emphasize lessons learned that will be folded into future development efforts. In our experience, a well-defined process that provides guidelines to ensure the project is cohesive and stays on track is key to success. Internal product deliveries with a planned test and feedback loop are critical. Release candidates are measured against use cases established early in the process, and provide the opportunity to assess priorities and make course corrections during development. Also key is the participation of a stakeholder such as a lead scientist who manages the technical questions, advises on priorities, and is actively involved as a lead tester. Finally, frequent scheduled communications (for example a bi-weekly tele-conference) assure issues are resolved quickly and the team is working toward a common visionComment: 7 pages, 2 figures, SPIE 2012 conferenc

A search for heavy Kaluza-Klein electroweak gauge bosons at the LHC

The feasibility for the observation of a certain leptonic Kaluza-Klein (KK) hard process in {\em pp} interactions at the LHC is presented. Within the $S^1/Z_2$ TeV$^{-1}$ extra dimensional theoretical framework with the focus on the KK excitations of the Standard Model $\gamma$ and $Z^0$ gauge bosons, the hard-process, $f\bar f \to \sum_n\left(\gamma^*/Z^*\right)_n \to F \bar F$, has been used where $f$ is the initial state parton, $F$ the final state lepton and $\left(\gamma^*/Z^*\right)_{n}$ is the $n^{\rm th}$ KK excitation of the $\gamma/Z^0$ boson. For this study the analytic form for the hard process cross section has been independently calculated by the authors and has been implemented using the {\sc Moses} framework. The Moses framework itself, that has been written by the authors, was used as an external process within the {\sc Pythia} Monte Carlo generator which provides the phase space generation for the final state leptons and partons from the initial state hadrons, and the simulation of initial and final state radiation and hadronization. A brief discussion of the possibility for observing and identifying the unique signature of the KK signal given the current LHC program is also presented.Comment: 16 pages 10 figures, MCnet number: MCnet/10/06, Accepted by JHE

Alcohol-related hypoglycemia in rural Uganda: socioeconomic and physiologic contrasts

Hypoglycemia is a rare but important complication seen in patients who present with alcohol intoxication. In a study by Marks and Teale, less than one percent of people with alcohol intoxication who presented to an American emergency department were hypoglycemic [1]. It is even more rare to see an intoxicated patient, who had been eating appropriately prior to or during the intoxication, present in a hypoglycemic coma. However, our analysis of the first 500 patients seen in a newly opened five-bed Emergency Department (ED) at Nyakibale Karoli Lwanga Hospital in rural southwestern Uganda, revealed multiple intoxicated patients who presented in hypoglycemic coma within hours of eating a full meal. Three of these cases are summarized and discussed below