Negative interference of icteric serum on a bichromatic biuret total protein assay.

Background: Bilirubin is stated to be a negative interferent in some biuret assays and thus could contribute to pseudohypoproteinemia in icteric samples. Objective: The purpose of the study was to evaluate the magnitude of and reason for a falsely low total protein concentration in icteric serum when the protein concentration is measured with a bichromatic spectrophotometric biuret assay. Methods: Commercially available bilirubin was dissolved in 0.1 M NaOH and then mixed with sera from 2 dogs to achieve various bilirubin concentrations of up to 40 mg/dL (first set of samples) and 35 mg/dL (second set of samples, for confirmation of first set of results and to explore the interference). Biuret total protein and bilirubin concentrations were determined with a chemistry analyzer (Cobas® 6000 with c501 module). Line graphs were drawn to illustrate the effects of increasing bilirubin concentrations on the total protein concentrations. Specific spectrophotometric absorbance readings were examined to identify the reason for the negative interference. Results: High bilirubin concentrations created a negative interference in the Cobas biuret assay. The detectable interference occurred with a spiked bilirubin concentration of 10.7 mg/dL in one set of samples and 20.8 mg/dL in a second set. The interference was due to a greater secondary absorbance reading at the second measuring point in the samples spiked with bilirubin, which possibly had converted to biliverdin. Conclusion: Marked hyperbilirubinemia is associated with a falsely low serum total protein concentrations when measured with a bichromatic spectrophotometric biuret assay. This can result in pseudohypoproteinemia and pseudohypoglobulinemia in icteric serum

The Global Impact of ITAR on the For-Profit and Non-Profit Space Communities

Under the United States Arms Export Control Act, the International Traffic in Arms Regulations (ITAR) control the export of technologies that are specified as defense articles on the United States Munitions List (USML). The Directorate of Defense Trade Controls (DDTC) within the Department of State (DoS) interprets and enforces these regulations in an effort to safeguard national security by denying advanced military technology to potential competitors

Predominance of Ehrlichia ewingii in Missouri dogs

To investigate the species distribution of Ehrlichia present in Missouri dogs, we tested 78 dogs suspected of having acute ehrlichiosis and 10 healthy dogs. Blood from each dog was screened with a broad-range 16S rRNA gene PCR assay that detects known pathogenic species of Ehrlichia and Anaplasma. The species was determined by using species-specific PCR assays and nucleotide sequencing. Ehrlichia antibody testing was performed by using an indirect immunofluorescence assay with Ehrlichia chaffeensis as the antigenic substrate. The broad-range assay detected Ehrlichia or Anaplasma DNA in 20 (26%) of the symptomatic dogs and 2 (20%) of the asymptomatic dogs. E. ewingii accounted for 20 (91%), and E. chaffeensis accounted for 1 (5%) of the positives. Anaplasma phagocytophilum DNA was detected in one dog, and the sequences of regions of the 16S rRNA gene and the groESL operon amplified from the blood of this dog matched the published sequences of this organism. Antibodies reactive with E. chaffeensis were detected in 14 (67%) of the 21 PCR-positive dogs and in 12 (19%) of the 64 PCR-negative dogs. Combining the results of PCR and serology indicated that 33 (39%) of 85 evaluable dogs had evidence of past or current Ehrlichia infection. We conclude that E. ewingii is the predominant etiologic agent of canine ehrlichiosis in the areas of Missouri included in this survey. E. canis, a widely recognized agent of canine ehrlichiosis, was not detected in any animal. The finding of E. ewingii in asymptomatic dogs suggests that dogs could be a reservoir for this Ehrlichia species

Constraints on the Ultra-High Energy Neutrino Flux from Gamma-Ray Bursts from a Prototype Station of the Askaryan Radio Array

We report on a search for ultra-high-energy (UHE) neutrinos from gamma-ray bursts (GRBs) in the data set collected by the Testbed station of the Askaryan Radio Array (ARA) in 2011 and 2012. From 57 selected GRBs, we observed no events that survive our cuts, which is consistent with 0.12 expected background events. Using NeuCosmA as a numerical GRB reference emission model, we estimate upper limits on the prompt UHE GRB neutrino fluence and quasi-diffuse flux from $10^{7}$ to $10^{10}$ GeV. This is the first limit on the prompt UHE GRB neutrino quasi-diffuse flux above $10^{7}$ GeV.Comment: 14 pages, 8 figures, Published in Astroparticle Physics Journa

Performance of two Askaryan Radio Array stations and first results in the search for ultra-high energy neutrinos

Ultra-high energy neutrinos are interesting messenger particles since, if detected, they can transmit exclusive information about ultra-high energy processes in the Universe. These particles, with energies above $10^{16}\mathrm{eV}$, interact very rarely. Therefore, detectors that instrument several gigatons of matter are needed to discover them. The ARA detector is currently being constructed at South Pole. It is designed to use the Askaryan effect, the emission of radio waves from neutrino-induced cascades in the South Pole ice, to detect neutrino interactions at very high energies. With antennas distributed among 37 widely-separated stations in the ice, such interactions can be observed in a volume of several hundred cubic kilometers. Currently 3 deep ARA stations are deployed in the ice of which two have been taking data since the beginning of the year 2013. In this publication, the ARA detector "as-built" and calibrations are described. Furthermore, the data reduction methods used to distinguish the rare radio signals from overwhelming backgrounds of thermal and anthropogenic origin are presented. Using data from only two stations over a short exposure time of 10 months, a neutrino flux limit of $3 \cdot 10^{-6} \mathrm{GeV} / (\mathrm{cm^2 \ s \ sr})$ is calculated for a particle energy of 10^{18}eV, which offers promise for the full ARA detector.Comment: 21 pages, 34 figures, 1 table, includes supplementary materia

First Constraints on the Ultra-High Energy Neutrino Flux from a Prototype Station of the Askaryan Radio Array

The Askaryan Radio Array (ARA) is an ultra-high energy ($>10^{17}$ eV) cosmic neutrino detector in phased construction near the South Pole. ARA searches for radio Cherenkov emission from particle cascades induced by neutrino interactions in the ice using radio frequency antennas ($\sim150-800$ MHz) deployed at a design depth of 200 m in the Antarctic ice. A prototype ARA Testbed station was deployed at $\sim30$ m depth in the 2010-2011 season and the first three full ARA stations were deployed in the 2011-2012 and 2012-2013 seasons. We present the first neutrino search with ARA using data taken in 2011 and 2012 with the ARA Testbed and the resulting constraints on the neutrino flux from $10^{17}-10^{21}$ eV.Comment: 26 pages, 15 figures. Since first revision, added section on systematic uncertainties, updated limits and uncertainty band with improvements to simulation, added appendix describing ray tracing algorithm. Final revision includes a section on cosmic ray backgrounds. Published in Astropart. Phys.