Experimental Test of Morphological Stability Theory for a Planar Interface During Rapid Solidification

We report a parameter-free test of the theory predicting the critical solute concentration that destabilizes a planar solid-liquid interface in the high-velocity regime where nonequilibrium interface kinetics are important. Rapid solidification following pulsed laser melting was used to make metastable solid solutions of silicon-tin. Rutherford backscattering spectrometry and transmission electron microscopy were used to measure the breakdown concentration. Samples remained microsegregation free with near perfect crystallinity at tin concentrations up to 10 times the maximum equilibrium solubility and 100 times that predicted by linear stability theory with local interfacial equilibrium. These measurements, covering velocities from 1 to 10 m/s, agree with the predictions of linear stability theory when the latter incorporates a velocity-dependent partition coefficient and a thermodynamically consistent kinetic liquidus, and contains no adjustable parameters. We also report a systematic increase of the breakdown concentration with increasing deviation from steady-state conditions, which is not addressed by current stability theories, parametrized by the concentration gradient just prior to breakdown.Engineering and Applied Science

Liquid Titanium Solute Diffusion Measured by Pulsed Ion-Beam Melting

The diffusivities of Sri, Mo, Zr, and Hf in liquid Ti were determined by pulsed ion-beam melting of thin liquid layers. Time-resolved optical reflectance and one-dimensional heat-flow simulations were employed to determine the melt duration. The broadening of nearly Gaussian solute concentration-depth profiles was determined ex situ using Rutherford backscattering spectrometry. Solute diffusivities in the range of 5 to 9 X 10-5 cm2/s were determined at temperatures in the range of 2200 to 2500 K. Calculations of buoyancy and Marangoni convection indicate that convective contamination is unlikely.Engineering and Applied Science

The L.E.A.D. Project: Leading educational achievement through dialogue 2010

The L.E.A.D. Project: Leading Educational Achievement Through Dialogue 2010 is the report of the research team from the University of Notre Dame Australia funded by the Australian Government Quality Teacher Program. It is a multi-site case study which gathered data on high performing secondary schools in the Catholic system of Western Australia The data was gathered from 9 secondary schools in the Catholic system. All Principals and Deputy Principals (Curriculum) were interviewed for the study. Focus groups of Heads of Learning were interviewed, in total 32 Heads of Learning participated. Focus groups of teachers were interviewed, in total 38 teachers participated in the interviews. Focus groups of recent past students were interviewed, in total 26 past students participated in the interviews. Focus groups of parents were interviewed, in total 28 parents participated. In addition a 21 item Likert scale survey was used to gather data from all teachers in the 9 schools in the study, a total of 447 teachers responded to the Likert scale (Appendix A)

Evidence For Temperature Change And Oblique Pulsation From Light Curve Fits Of The Pulsating White Dwarf GD 358

Convective driving, the mechanism originally proposed by Brickhill for pulsating white dwarf stars, has gained general acceptance as the generic linear instability mechanism in DAV and dbV white dwarfs. This physical mechanism naturally leads to a nonlinear formulation, reproducing the observed light curves of many pulsating white dwarfs. This numerical model can also provide information on the average depth of a star's convection zone and the inclination angle of its pulsation axis. In this paper, we give two sets of results of nonlinear light curve fits to data on the dbV GD 358. Our first fit is based on data gathered in 2006 by the Whole Earth Telescope; this data set was multiperiodic containing at least 12 individual modes. Our second fit utilizes data obtained in 1996, when GD 358 underwent a dramatic change in excited frequencies accompanied by a rapid increase in fractional amplitude; during this event it was essentially monoperiodic. We argue that GD 358's convection zone was much thinner in 1996 than in 2006, and we interpret this as a result of a short-lived increase in its surface temperature. In addition, we find strong evidence of oblique pulsation using two sets of evenly split triplets in the 2006 data. This marks the first time that oblique pulsation has been identified in a variable white dwarf star.Delaware Asteroseismic Research CenterNational Science Foundation AST-0909107, AST-0607840Norman Hackerman Advanced Research Program 003658-0255-2007Crystal Trust FoundationMt. Cuba ObservatoryUniversity of DelawareAstronom

Maternal obesogenic diet enhances cholestatic liver disease in offspring

Human and animal model data show that maternal obesity promotes nonalcoholic fatty liver disease in offspring and alters bile acid (BA) homeostasis. Here we investigated whether offspring exposed to maternal obesogenic diets exhibited greater cholestatic injury. We fed female C57Bl6 mice conventional chow (CON) or high fat/high sucrose (HF/HS) diet and then bred them with lean males. Offspring were fed 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) for 2 weeks to induce cholestasis, and a subgroup was then fed CON for an additional 10 days. Additionally, to evaluate the role of the gut microbiome, we fed antibiotic-treated mice cecal contents from CON or HF/HS offspring, followed by DDC for 2 weeks. We found that HF/HS offspring fed DDC exhibited increased fine branching of the bile duct (ductular reaction) and fibrosis but did not differ in BA pool size or intrahepatic BA profile compared to offspring of mice fed CON. We also found that after 10 days recovery, HF/HS offspring exhibited sustained ductular reaction and periportal fibrosis, while lesions in CON offspring were resolved. In addition, cecal microbiome transplant from HF/HS offspring donors worsened ductular reaction, inflammation, and fibrosis in mice fed DDC. Finally, transfer of the microbiome from HF/HS offspring replicated the cholestatic liver injury phenotype. Taken together, we conclude that maternal HF/HS diet predisposes offspring to increased cholestatic injury after DDC feeding and delays recovery after returning to CON diets. These findings highlight the impact of maternal obesogenic diet on hepatobiliary injury and repair pathways during experimental cholestasis

Multiple Myeloma Vaccination Patterns in a Large Health System: A Pilot Study

Purpose: Common reasons for hospitalization and death in patients with multiple myeloma (MM) are infections. As patients with MM are living longer and are treated with immunomodulatory drugs, there is a need to immunize against vaccine-preventable diseases and ultimately determine the efficacy of these vaccines. We evaluated vaccination practice patterns in MM patients at our health system using electronic medical records and data analytics. Methods: This institutional review board-approved study retrospectively reviewed patients with MM who visited the health system from May 2012 to May 2014. Data collected included demographics, influenza vaccination (FV) and pneumonia vaccination (PV) history, hospitalization episodes and associated costs, and duration of survival. Patients were considered PV-positive if vaccinated within 5 years prior to study. FV was defined as optimal (two FV in 2012–2014), suboptimal (one FV in 2012–2014) or none (in 2012–2014). Results: Of 411 MM patients, 55% were male and 85% Caucasian. Nearly 58% received PV in the past 5 years. FV was 15% optimal, 52% suboptimal and 33% none. A total of 444 hospitalizations involving 204 patients were observed over 2-year follow-up. More than $23 million was incurred from hospitalizations in the 2-year study period. There was no statistically significant difference in all-cause hospitalization and overall survival by FV and PV status. Conclusions: Despite recommendations of vaccination in multiple myeloma, our cohort had low rates of influenza and pneumonia vaccination. FV and PV status did not show any significant association with additional hospitalization or overall survival in this pilot study. Future prospective studies are needed to ascertain the immunological and clinical efficacy and effectiveness of these vaccines in immunosuppressed patients

Thermodynamic route of Nb3Sn nucleation: Role of oxygen

Intermetallic Nb3Sn alloys have long been believed to form through Sn diffusion into Nb. However, our observations of significant oxygen content in Nb3Sn prompted an investigation of alternative formation mechanisms. Through experiments involving different oxide interfaces (clean HF-treated, native oxidized, and anodized), we demonstrate a thermodynamic route that fundamentally challenges the conventional Sn diffusion mechanism for Nb3Sn nucleation. Our results highlight the critical involvement of a SnOx intermediate phase. This new nucleation mechanism identifies the principles for growth optimization and new synthesis of high-quality Nb3Sn superconductors

Book Reviews

Reproductive Biology and Phylogeny of Lizards and Tuatara. J. L. Rheubert, D. S. Siegel, and S. E. Trauth (Eds.). 2014. CRC Press. ISBN 9781466579866. 760 p. $143.96 (hardcover).— According to the authors, this book was intended to summarize the current knowledge of phylo- geny and reproduction of the Lepidosauria. I believe the authors have achieved their goal. Many of the chapters in this book are derived from presentations that took place at the Symposium on Reproductive Biology of Lizards at the Joint Meeting of Ichthyologists and Herpetologists held in Chattanooga, Tennessee in 2014. Although the majority of the authors are from the United States, the book includes authors from nine countries representing four continents and New Zealand. In the first chapter, Laurie Vitt states (p. 1), “It is difficult to imagine anything more interesting to biologists... than understanding the origins of reproductive patterns among lizards.” I agree. Vitt continues with the early history of topics such as seasonality of reproduction and fat storage, parthenogenesis, evolution of viviparity, placentation, and several other topics. For each of these topics, Vitt explains the origin of the field and the major researchers responsible for the insights and hypotheses in each field. His chapter ends with a call for natural history studies. In chapter two, John Wiens and Shea Lambert discuss the phylogeny of lizard families. They present a compelling argument for combining molecular and morphological data sets in phylogenetic studies. The authors admit that there are still many unresolved issues and more data are needed to fully understand the phylogeny of the lizards. In chapter three, Jose ́ Mart ́ın and Pilar Lo ́ pez define pheromone, discuss chemosensory abilities, and describe the role of pheromones in lizard reproduction. They present a list of studies on lizards and Tuatara, describe the source of chemicals, and the chemical nature of putative phero- mones. Mart ́ın and Lo ́pez conclude with the evolutionary origin of chemical signaling in lizards and a call for additional work on pheromone communication in lizards. Robert Cox and Atiel Kahrl discuss sexual selection and sexual dimorphism in lizards in chapter four. They include a list of studies and evaluate the data to determine what factors led to sexual dimorphism. They discuss intra- and intersexual selection. Cox and Kahrl discuss the ultimate cause and proximate mechanisms for sexual dimorphism and conclude with a discussion of the consequence of sexual selection on speciation and species recognition

Widespread mRNA Association with Cytoskeletal Motor Proteins and Identification and Dynamics of Myosin-Associated mRNAs in S. cerevisiae

Programmed mRNA localization to specific subcellular compartments for localized translation is a fundamental mechanism of post-transcriptional regulation that affects many, and possibly all, mRNAs in eukaryotes. We describe her e a systematic approach to identify the RNA cargoes associated with the cytoskeletal motor proteins of Saccharomyces cerevisiae in combination with live-cell 3D super-localization microscopy of endogenously tagged mRNAs. Our analysis identified widespread association of mRNAs with cytoskeletal motor proteins, including association of Myo3 with mRNAs encoding key regulators of actin branching and endocytosis such as WASP and WIP. Using conventional fluorescence microscopy and expression of MS2-tagged mRNAs from endogenous loci, we observed a strong bias for actin patch nucleator mRNAs to localize to the cell cortex and the actin patch in a Myo3- and F-actin dependent manner. Use of a double-helix point spread function (DH-PSF) microscope allowed super-localization measurements of single mRNPs at a spatial precision of 25 nm in x and y and 50 nm in z in live cells with 50 ms exposure times, allowing quantitative profiling of mRNP dynamics. The actin patch mRNA exhibited distinct and characteristic diffusion coefficients when compared to a control mRNA. In addition, disruption of F-actin significantly expanded the 3D confinement radius of an actin patch nucleator mRNA, providing a quantitative assessment of the contribution of the actin cytoskeleton to mRNP dynamic localization. Our results provide evidence for specific association of mRNAs with cytoskeletal motor proteins in yeast, suggest that different mRNPs have distinct and characteristic dynamics, and lend insight into the mechanism of actin patch nucleator mRNA localization to actin patches