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Light-Mediated Control of Polymeric Materials
The synthesis and characterization of precision polymeric materials represents a broad research area with significant value to society. Recently, light-mediated approaches to controlled polymer synthesis have attracted significant interest due to the low cost and tremendous tunability of modern light sources. Through manipulating these various properties (wavelength, intensity, etc), researchers have made considerable progress in controlling a wide range of important polymeric properties such as molecular weight distribution, comonomer composition, and molecular architecture. However, the systems developed to date have largely focused on homogenous targets and have lacked in-depth photophysical interpretation. This dissertation describes the development of an in-situ approach to studying light-mediated chemical reactions and efforts to better understand the temporal control of state-of-the-art photopolymerizations. Furthermore, the lessons learned from these studies led to the development of a new approach to 3D printing, wherein specific wavelengths of visible light were used to independently and simultaneously define local materials properties throughout a part in a single step. This breakthrough in additive manufacturing greatly expands the potential of multi-material printing techniques. The findings of these works have broad implications for using light as a tool for the future development of synthetic approaches to advanced polymeric materials
Search for the scalar and mesons in the reactions
It is shown that the reactions give a good
chance for observing scalar and mesons. In the photon energy region
less then 100 MeV the vector meson contributions are negligible in comparison with the scalar
mesons for
greater than
. Using two-channel treatment of the
scattering the predictions for
are derived. The four quark model, the model of molecule and
the model of scalar and mesons are discussed.Comment: 31 pages, 10 ps files of figures, minor numerical changes, Appendix
corrected, to be published in Phys.Rev.
Prevalence of filarioid nematodes and trypanosomes in American robins and house sparrows, Chicago USA
AbstractHosts are commonly infected with a suite of parasites, and interactions among these parasites can affect the size, structure, and behavior of host–parasite communities. As an important step to understanding the significance of co-circulating parasites, we describe prevalence of co-circulating hemoparasites in two important avian amplification hosts for West Nile virus (WNV), the American robin (Turdus migratorius) and house sparrow (Passer domesticus), during the 2010–2011 in Chicago, Illinois, USA. Rates of nematode microfilariemia were 1.5% of the robins (n=70) and 4.2% of the house sparrows (n=72) collected during the day and 11.1% of the roosting robins (n=63) and 0% of the house sparrows (n=11) collected at night. Phylogenetic analysis of nucleotide sequences of the 18S rRNA and cytochrome oxidase subunit I (COI) genes from these parasites resolved two clades of filarioid nematodes. Microscopy revealed that 18.0% of American robins (n=133) and 16.9% of house sparrows (n=83) hosted trypanosomes in the blood. Phylogenetic analysis of nucleotide sequences from the 18s rRNA gene revealed that the trypanosomes fall within previously described avian trypanosome clades. These results document hemoparasites in the blood of WNV hosts in a center of endemic WNV transmission, suggesting a potential for direct or indirect interactions with the virus
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