1,271 research outputs found
Method of forming electronically conducting polymers on conducting and nonconducting substrates
The present invention provides electronically conducting polymer films formed from photosensitive formulations of pyrrole and an electron acceptor that have been selectively exposed to UV light, laser light, or electron beams. The formulations may include photoinitiators, flexibilizers, solvents and the like. These solutions can be used in applications including printed circuit boards and through-hole plating and enable direct metallization processes on non-conducting substrates. After forming the conductive polymer patterns, a printed wiring board can be formed by sensitizing the polymer with palladium and electrolytically depositing copper
The Effects of Feeding on Hematological and Plasma Biochemical Profiles in Green (Chelonia mydas) and Kemp's Ridley (Lepidochelys kempii) Sea Turtles
In mammals, lipemic blood from sampling too soon after an animal feeds can have substantial effects on biochemical values. Plasma biochemical values in reptiles may be affected by species, age, season, and nutritional state. However, fasting status is not routinely considered when sampling reptile blood. In this paper, we evaluated 2-hour postprandial blood collection in two sea turtle species to investigate the effects of feeding on hematological and plasma biochemical values. Feeding had no significant effects on hematological values in either species, nor did it have an effect on plasma biochemistry values in Kemp's ridley sea turtles. In postprandial green turtles, total protein, albumin, ALP, AST, ALT, amylase, and cholesterol increased significantly, and chloride decreased significantly. Although statistically significant changes were observed, the median percent differences between pre- and postprandial values did not exceed 10% for any of these analytes and would not likely alter the clinical interpretation
The GALEX View of "Boyajian's Star" (KIC 8462852)
The enigmatic star KIC 8462852, informally known as "Boyajian's Star", has
exhibited unexplained variability from both short timescale (days) dimming
events, and years-long fading in the Kepler mission. No single physical
mechanism has successfully explained these observations to date. Here we
investigate the ultraviolet variability of KIC 8462852 on a range of timescales
using data from the GALEX mission that occurred contemporaneously with the
Kepler mission. The wide wavelength baseline between the Kepler and GALEX data
provides a unique constraint on the nature of the variability. Using 1600
seconds of photon-counting data from four GALEX visits spread over 70 days in
2011, we find no coherent NUV variability in the system on 10-100 second or
months timescales. Comparing the integrated flux from these 2011 visits to the
2012 NUV flux published in the GALEX-CAUSE Kepler survey, we find a 3% decrease
in brightness for KIC 8462852. We find this level of variability is
significant, but not necessarily unusual for stars of similar spectral type in
the GALEX data. This decrease coincides with the secular optical fading
reported by Montet & Simon (2016). We find the multi-wavelength variability is
somewhat inconsistent with typical interstellar dust absorption, but instead
favors a R = 5.0 0.9 reddening law potentially from circumstellar
dust.Comment: 8 pages, 4 figures, ApJ Accepte
Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock
Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations
Application of a policy framework for the public funding of drugs for rare diseases
BACKGROUND: In many countries, decisions about the public funding of drugs are preferentially based on the results of randomized trials. For truly rare diseases, such trials are not typically available, and approaches by public payers are highly variable. In view of this, a policy framework intended to fairly evaluate these drugs was developed by the Drugs for Rare Diseases Working Group (DRDWG) at the request of the Ontario Public Drug Programs. OBJECTIVE: To report the initial experience of applying a novel evaluation framework to funding applications for drugs for rare diseases. METHODS: Retrospective observational cohort study. MEASURES: Clinical effectiveness, costs, funding recommendations, funding approval. KEY RESULTS: Between March 2008 and February 2013, eight drugs were evaluated using the DRDWG framework. The estimated average annual drug cost per patient ranged from 28,000 to 1,200,000 Canadian dollars (CAD). For five drugs, full evaluations were completed, specific funding recommendations were made by the DRDWG, and funding was approved after risk-sharing agreements with the manufacturers were negotiated. For two drugs, the disease indications were determined to be ineligible for consideration. For one drug, there was insufficient natural history data for the disease to provide a basis for recommendation. For the five drugs fully evaluated, 32 patients met the predefined eligibility criteria for funding, and five were denied based on predefined exclusion criteria. CONCLUSIONS: The framework improved transparency and consistency for evaluation and public funding of drugs for rare diseases in Ontario. The evaluation process will continue to be iteratively refined as feedback on actual versus expected clinical and economic outcomes is incorporated. © 2014 Society of General Internal Medicine
The Different Structures of the Two Classes of Starless Cores
We describe a model for the thermal and dynamical equilibrium of starless
cores that includes the radiative transfer of the gas and dust and simple CO
chemistry. The model shows that the structure and behavior of the cores is
significantly different depending on whether the central density is either
above or below about 10^5 cm-3. This density is significant as the critical
density for gas cooling by gas-dust collisions and also as the critical density
for dynamical stability, given the typical properties of the starless cores.
The starless cores thus divide into two classes that we refer to as thermally
super-critical and thermally sub-critical.This two-class distinction allows an
improved interpretation of the different observational data of starless cores
within a single model.Comment: ApJ in pres
EGFR oligomerization organizes kinase-active dimers into competent signalling platforms
Epidermal growth factor receptor (EGFR) signalling is activated by ligand-induced receptor dimerization. Notably, ligand binding also induces EGFR oligomerization, but the structures and functions of the oligomers are poorly understood. Here, we use fluorophore localization imaging with photobleaching to probe the structure of EGFR oligomers. We find that at physiological epidermal growth factor (EGF) concentrations, EGFR assembles into oligomers, as indicated by pairwise distances of receptor-bound fluorophore-conjugated EGF ligands. The pairwise ligand distances correspond well with the predictions of our structural model of the oligomers constructed from molecular dynamics simulations. The model suggests that oligomerization is mediated extracellularly by unoccupied ligand-binding sites and that oligomerization organizes kinase-active dimers in ways optimal for auto-phosphorylation in trans between neighbouring dimers. We argue that ligand-induced oligomerization is essential to the regulation of EGFR signalling
Characteristics of Kepler Planetary Candidates Based on the First Data Set: The Majority are Found to be Neptune-Size and Smaller
In the spring of 2009, the Kepler Mission commenced high-precision photometry
on nearly 156,000 stars to determine the frequency and characteristics of small
exoplanets, conduct a guest observer program, and obtain asteroseismic data on
a wide variety of stars. On 15 June 2010 the Kepler Mission released data from
the first quarter of observations. At the time of this publication, 706 stars
from this first data set have exoplanet candidates with sizes from as small as
that of the Earth to larger than that of Jupiter. Here we give the identity and
characteristics of 306 released stars with planetary candidates. Data for the
remaining 400 stars with planetary candidates will be released in February
2011. Over half the candidates on the released list have radii less than half
that of Jupiter. The released stars include five possible multi-planet systems.
One of these has two Neptune-size (2.3 and 2.5 Earth-radius) candidates with
near-resonant periods.Comment: Paper to accompany Kepler's June 15, 2010 data release; submitted to
Astrophysical Journal Figures 1,2,& 3 revised. Improved labeling on all
figures. Slight changes to planet frequencies in result
Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data
New transiting planet candidates are identified in sixteen months (May 2009 -
September 2010) of data from the Kepler spacecraft. Nearly five thousand
periodic transit-like signals are vetted against astrophysical and instrumental
false positives yielding 1,091 viable new planet candidates, bringing the total
count up to over 2,300. Improved vetting metrics are employed, contributing to
higher catalog reliability. Most notable is the noise-weighted robust averaging
of multi-quarter photo-center offsets derived from difference image analysis
which identifies likely background eclipsing binaries. Twenty-two months of
photometry are used for the purpose of characterizing each of the new
candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are
tabulated as well as the products of light curve modeling: reduced radius
(Rp/R*), reduced semi-major axis (d/R*), and impact parameter (b). The largest
fractional increases are seen for the smallest planet candidates (197% for
candidates smaller than 2Re compared to 52% for candidates larger than 2Re) and
those at longer orbital periods (123% for candidates outside of 50-day orbits
versus 85% for candidates inside of 50-day orbits). The gains are larger than
expected from increasing the observing window from thirteen months (Quarter 1--
Quarter 5) to sixteen months (Quarter 1 -- Quarter 6). This demonstrates the
benefit of continued development of pipeline analysis software. The fraction of
all host stars with multiple candidates has grown from 17% to 20%, and the
paucity of short-period giant planets in multiple systems is still evident. The
progression toward smaller planets at longer orbital periods with each new
catalog release suggests that Earth-size planets in the Habitable Zone are
forthcoming if, indeed, such planets are abundant.Comment: Submitted to ApJS. Machine-readable tables are available at
http://kepler.nasa.gov, http://archive.stsci.edu/kepler/results.html, and the
NASA Exoplanet Archiv
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