Alien Registration- Quance, Albert J. (Auburn, Androscoggin County)

https://digitalmaine.com/alien_docs/30273/thumbnail.jp

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

Genomics of Brucellosis in Wildlife and Livestock of the Greater Yellowstone Ecosystem

Brucellosis, a disease caused by the bacterium Brucella abortus, has recently been expanding its distribution in the Greater Yellowstone Ecosystem (GYE), with increased outbreaks in cattle and rising seroprevalence in elk (Cervus elaphus) over the past decade. Genetic studies suggest elk are a primary source of recent transmission to cattle. However, these studies are based on Variable Number Tandem Repeat (VNTR) data, which are limited in assessing and quantifying transmission among species. The goal of this study was to (i) investigate the introduction history of B. abortus in the GYE, (ii) identify B. abortus lineages associated with host species and/or geographic localities, and (iii) quantify transmission across wildlife and livestock host species and populations. We sequenced B. abortus whole genomes (n= 207) derived from isolates collected from three host species (bison, elk, cattle) over the past 30 years, throughout the GYE. We identified genetic variation among isolates, and applied a spatial diffusion phylogeographic modeling approach that incorporated temporal information from sampling. Based on these data, our results suggest four divergent Brucella lineages, with a time to most recent common ancestor of ~130 years ago, possibly representing a minimum of four brucellosis introductions into the GYE. Two Brucella lineages were generally clustered by geography. Evidence for cross-species transmission was detected among all species, though most events occur within species and herds. Understanding transmission dynamics is imperative for implementing effective control measures and may assist in identifying source populations responsible for past and future brucellosis infections in wildlife and outbreaks in livestock

Alien Registration- Quance, Albert J. (Auburn, Androscoggin County)

https://digitalmaine.com/alien_docs/30273/thumbnail.jp

Formation of high-quality silicon dioxide films by electron cyclotron resonance plasma oxidation and plasma-enhanced chemical vapour deposition

High-quality silicon dioxide films have been deposited by plasma-enhanced chemical vapour deposition and plasma oxidation using a single magnet electron cyclotron resonance plasma generator with both oxygen and nitrous oxide as the oxygen source, Langmuir probe measurements were used to characterise both molecular oxygen and nitrous oxide discharges. Low electron temperatures, resulting in low sheath potential drops, coupled with the shape of the field lines results in low sputtering from the chamber walls between the source region and substrate. The resulting buildup of an insulating layer of oxide on the chamber walls results in a very clean process. In situ thermal desorption and ellipsometry measurements coupled with X-ray photoelectron spectroscopy have allowed us to characterise the quality of the silicon surface prior to deposition and just after initiation of the plasma. Plasma oxidation dominates over chemical vapour deposition during the early stages of oxide film growth using either oxygen or nitrous oxide as the oxygen source gas. Extensive ex-situ spectroscopic ellipsometry (SE) indicates that the bulk properties of the films arc comparable to those of high-temperature thermal oxides. There is no interface layer measurable by SE for any of the films produced by plasma oxidation or chemical vapour deposition with silane using either molecular oxygen or nitrous oxide as the oxygen source gas even though the latter results in approximately a monolayer of nitrogen at the Si/SiO2 interface. Chemical analysis by the total reflected X-ray fluorescence technique and by vapour-phase deposition coupled with graphite furnace atomic absorption spectroscopy found no impurities in the films made with silane and molecular oxygen. The high quality of the Si/SiO2 interface made with these two gases was confirmed by capacitance-voltage measurements on Al-gate capacitors. After a 1 min anneal at 950\ub0C interface state densities below 3 71010 eV 121 cm 122 were obtained.Peer reviewed: YesNRC publication: Ye

Critical role of gas phase diffusion and high efficiency in vertically aligned carbon nanotube forest growth

Here the growth kinetics of vertically aligned carbon nanotube forests depend on the size of the patterned catalyst films from which they grow. Forests are grown using chemical vapor deposition on thin film catalyst islands patterned at the 100 \u3bcm scale on silicon wafers. The smaller the pattern, the faster the forest grows and the earlier it stops growing. Furthermore, the shape and structure of the forests, in particular the concavity of their top surface, also depend on the size of the catalyst islands. This result can be understood as a consequence of the high efficiency by which the acetylene source gas is converted into carbon nanotubes (here 3c30%) and a varying local amount of acetylene source gas available for growth. A diffusion model can explain the observed shape and structure of the forests and their growth kinetics by using experimentally measured parameters. This model also gives insight into the density and growth rate of carbon nanotube forests and suggests a mechanism that coordinates growth rates across the sample and, under certain conditions, can limit the fraction of catalyst nanoparticles that produce nanotubes.Peer reviewed: YesNRC publication: Ye

Identification of Brucella suis from Feral Swine in Selected States in the USA

Serologic tests currently available for brucellosis diagnosis detect antibodies to Brucella but do not distinguish between species of Brucella. Although Brucella suis is known to circulate within various feral swine (Sus scrofa) populations, our objective was to determine the primary species of Brucella circulating in feral swine populations in areas of the US with high brucellosis prevalence. We cultured lymph nodes from 183 feral swine. We identified 22 isolates from 21 animals, and all isolates were genotyped as B. suis. Most isolates were B. suis biovar 1, with the exception of two genetically distinct isolates from one feral swine in Hawaii, which were identified as B. suis biovar 3. Serum from each feral swine was also tested by the fluorescence polarization assay when possible, but only 52% (95% CL529.8–74.3) of culture-positive animals were antibody positive. Our results indicate that brucellosis infections in feral swine within the US are typically caused by B. suis. However, improved serologic tests are needed to more accurately determine exposure to Brucella spp. and to monitor disease trends in feral swine populations