The February 5, 1965 solar proton event 2 - Low energy proton observations and their relation to the magnetosphere

Temporal and spatial behavior of low energy solar protons in magnetospher

Proton energy into the magnetosphere on 26 May 1967

Proton entry into magnetosphere over polar cap on 26 May 196

Electrical isolation of GaN by MeV ion irradiation

The evolution of sheet resistance of n-type GaN epilayers exposed to irradiation with MeV H, Li, C, and O ions is studied in situ. Results show that the threshold dose necessary for complete isolation linearly depends on the original free electron concentration and reciprocally depends on the number of atomic displacements produced by ion irradiation. Furthermore, such isolation is stable to rapid thermal annealing at temperatures up to 900 °C. In addition to providing a better understanding of the physical mechanisms responsible for electrical isolation, these results can be used for choosing implant conditions necessary for an effective electrical isolation of GaN-based devices.This work was partly supported by Conselho Nacional de Pesquisas (CNPq, Brazil) under Contract No. 200541/ 99-4

Mechanisms of burst release from pH-responsive polymeric microparticles.

Microencapsulation of drugs into preformed polymers is commonly achieved through solvent evaporation techniques or spray drying. We compared these encapsulation methods in terms of controlled drug release properties of the prepared microparticles and investigated the underlying mechanisms responsible for the “burst release” effect. Using two different pH-responsive polymers with a dissolution threshold of pH 6 (Eudragit L100 and AQOAT AS-MG), hydrocortisone, a model hydrophobic drug, was incorporated into microparticles below and above its solubility within the polymer matrix. Although, spray drying is an attractive approach due to rapid particle production and relatively low solvent waste, the oil-in-oil microencapsulation method is superior in terms of controlled drug release properties from the microparticles. Slow solvent evaporation during the oil-in-oil emulsification process allows adequate time for drug and polymer redistribution in the microparticles and reduces uncontrolled drug burst release. Electron microscopy showed that this slower manufacturing procedure generated non-porous particles whereas thermal analysis and X-ray diffractometry showed that drug loading above the solubility limit of the drug in the polymer generated excess crystalline drug on the surface of the particles. Raman spectral mapping illustrated that drug was homogeneously distributed as a solid solution in the particles when loaded below saturation in the polymer with consequently minimal burst release

Radiotelemetry Of Heart Rates From Free-Ranging Gulls

A lightweight radiotelemetry system with a range of 80 km was used to monitor heart rate from free-ranging Herring Gulls on flights of up to 20 km. Heart rate varied from 130 beats/min in a resting bird to 625 beats/min for sustained flight. Soaring birds showed rates similar to those of birds sitting quietly on the ground. Simultaneous records of telemetered heart rate and intraspecific conflict on the nesting island revealed that cardiac acceleration preceded overt visual communication. Intensely aggressive behavior was accompanied by heart rates approaching those of sustained flight. Heart rate as a measure of metabolic cost indicates that the gull\u27s behavioral adaptations for long-distance flight, food location and intraspecific communication result in major energy savings

Progress in Lunar Laser Ranging Tests of Relativistic Gravity

Analyses of laser ranges to the Moon provide increasingly stringent limits on any violation of the Equivalence Principle (EP); they also enable several very accurate tests of relativistic gravity. We report the results of our recent analysis of Lunar Laser Ranging (LLR) data giving an EP test of \Delta (M_G/M_I)_{EP} =(-1.0 +/- 1.4) x 10^{-13}. This result yields a Strong Equivalence Principle (SEP) test of \Delta (M_G/M_I)_{SEP} =(-2.0 +/- 2.0) x 10^{-13}. Also, the corresponding SEP violation parameter \eta is (4.4 +/- 4.5) x 10^{-4}, where \eta=4\beta-\gamma-3 and both \beta and \gamma are parametrized post-Newtonian (PPN) parameters. Using the recent Cassini result for the parameter \gamma, PPN parameter \beta is determined to be \beta-1=(1.2 +/- 1.1) x 10^{-4}. The geodetic precession test, expressed as a relative deviation from general relativity, is K_{gp}=-0.0019 +/- 0.0064. The search for a time variation in the gravitational constant results in \dot G/G=(4 +/- 9) x 10^{-13} yr^{-1}, consequently there is no evidence for local (~1AU) scale expansion of the solar system.Comment: 4 pages, revtex4, minor changes made for publicatio

Cardiopulmonary exercise testing in young people with cystic fibrosis

This is the author accepted manuscript. The final version is available to members only from BASES via the link in this record.First published in The Sport and Exercise Scientist, Vol. 61, p. 22 (Autumn 2019). Published by the British Association of Sport and Exercise Sciences – www.bases.org.u

Mouse Models of Prostate Cancer

The development and optimization of high-throughput screening methods has identified a multitude of genetic changes associated with human disease. The use of immunodeficient and genetically engineered mouse models that mimic the human disease has been crucial in validating the importance of these genetic pathways in prostate cancer. These models provide a platform for finding novel therapies to treat human patients afflicted with prostate cancer as well as those who have debilitating bone metastases. In this paper, we focus on the historical development and phenotypic descriptions of mouse models used to study prostate cancer. We also comment on how closely each model recapitulates human prostate cancer