642 research outputs found

    Analyzing Feshbach resonances -- A 6^6Li -133^{133}Cs case study

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    We provide a comprehensive comparison of a coupled channels calculation, the asymptotic bound state model (ABM), and the multichannel quantum defect theory (MQDT). Quantitative results for 6^6Li -133^{133}Cs are presented and compared to previously measured 6^6Li -133^{133}Cs Feshbach resonances (FRs) [M. Repp et al., Phys. Rev. A 87 010701(R) (2013)]. We demonstrate how the accuracy of the ABM can be stepwise improved by including magnetic dipole-dipole interactions and coupling to a non-dominant virtual state. We present a MQDT calculation, where magnetic dipole-dipole and second order spin-orbit interactions are included. A frame transformation formalism is introduced, which allows the assignment of measured FRs with only three parameters. All three models achieve a total rms error of < 1G on the observed FRs. We critically compare the different models in view of the accuracy for the description of FRs and the required input parameters for the calculations.Comment: 16 pages, 3 figures, 1 tabl

    Cooperation between COA6 and SCO2 in COX2 maturation during cytochrome c oxidase assembly links two mitochondrial cardiomyopathies.

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    Three mitochondria-encoded subunits form the catalytic core of cytochrome c oxidase, the terminal enzyme of the respiratory chain. COX1 and COX2 contain heme and copper redox centers, which are integrated during assembly of the enzyme. Defects in this process lead to an enzyme deficiency and manifest as mitochondrial disorders in humans. Here we demonstrate that COA6 is specifically required for COX2 biogenesis. Absence of COA6 leads to fast turnover of newly synthesized COX2 and a concomitant reduction in cytochrome c oxidase levels. COA6 interacts transiently with the copper-containing catalytic domain of newly synthesized COX2. Interestingly, similar to the copper metallochaperone SCO2, loss of COA6 causes cardiomyopathy in humans. We show that COA6 and SCO2 interact and that corresponding pathogenic mutations in each protein affect complex formation. Our analyses define COA6 as a constituent of the mitochondrial copper relay system, linking defects in COX2 metallation to cardiac cytochrome c oxidase deficiency

    Synthesis and characterisation of ruthenium complexes containing a pendent catechol ring

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    A series of [Ru(bipy)₂L]⁺ and [Ru(phen)₂L]⁺ complexes where L is 2-[5-(3,4-dimethoxyphenyl)-4H-1,2,4-triazol-3-yl]pyridine (HL1) and 4-(5-pyridin-2-yl-4H-1,2,4-triazol-3-yl)benzene-1,2-diol (HL2) are reported. The compounds obtained have been characterised using X-ray crystallography, NMR, UV/Vis and emission spectroscopies. Partial deuteriation is used to determine the nature of the emitting state and to simplify the NMR spectra. The acid-base properties of the compounds are also investigated. The electronic structures of [Ru(bipy)₂L1]⁺ and Ru(bipy)₂HL1]²⁺ are examined using ZINDO. Electro and spectroelectrochemical studies on [Ru(bipy)₂(L2)]⁺ suggest that proton transfer between the catechol and triazole moieties on L2 takes place upon oxidation of the L2 ligand

    Comparing Common Techniques for Calculating Parasite Prevalence

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    Raccoons (Procyon lotor) are the final host for raccoon roundworms (Baylisascaris procyonis). Raccoon roundworm is the leading cause of a dangerous neurological disease, known as larva migrans encephalopathy. Diagnostic tools for detecting the presence of B. procyonis within a raccoon population include necropsy, fecal flotation, and latrine analysis. Necropsies yield the highest measure of prevalence, with fecal flotation and latrine analysis often underestimating infection rates. We necropsied 225 raccoons gathered from 10 townships of Clark and Greene Counties in Ohio. We collected fecal samples from 95 raccoons negative for B. procyonis at necropsy. We suspended the feces in Sheather’s solution to float any eggs, and prepared slides from this solution. Nearly 14% of raccoons negative at necropsy for B. procyonis possessed eggs in their feces. We used a chi squared test for equality of distributions to determine the likelihood that a positive fecal analysis is related to B. procyonis prevalence or to the area in which the raccoon was trapped. These data will help us determine how well fecal analyses estimate parasite prevalence

    Evidence for Secretion of a Netrin-1-like Protein by Tetrahymena thermophila

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    Netrin-1 is a pleiotropic signaling molecule with targets in many mammalian cell types. Though first characterized as a chemotactic signal involved in neuronal guidance during development, netrin-1 has since been found to have a regulatory role in angiogenesis, and is also used as a biomarker in certain cancers. Tetrahymena thermophila are free-living protists that rely on chemotactic signals to find food, as well as to escape predators. Chemoattractants cause the cells to swim faster in the forward direction, while chemorepellents cause ciliary reversal, resulting in movement of the cell away from the noxious stimulus. We have previously found that netrin-1 is a chemorepellent in T. thermophila. More recently, we have detected netrin-1 by ELISA in both whole cell extract and secreted protein samples obtained from T. thermophila. In addition, we have immunolocalized netrin-1 staining to the cytosol of T. thermophila using an anti-netrin-1 antibody. We are currently running Western blots to determine the molecular weight of this protein and compare it to its vertebrate counterparts. Further experimentation is needed to determine the physiological role of this protein in T. thermophila

    Does Baylisascaris procyonis Phylogeny Correlate with That of the Raccoon (Procyon lotor)

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    Baylisacaris procyonis, commonly known as the raccoon roundworm, is a parasite that inhabits the small intestine of the North American raccoon (Procyon lotor). Although humans do not typically become the definitive host, humans can become infected through handling soil containing eggs. B. procyonis can induce serious health complications in cases of human infection, including degenerative retinal and behavioral changes, coma, and even death. High prevalence of B. procyonis in a raccoon population increases the probability of transference to human hosts. In our study, we analyzed the genetic structure of B. procyonis harvested from raccoons of southwestern Ohio, and compared this to the genetic structure of the raccoons they inhabited. It is our hypothesis that the genetic structuring of the roundworms is the same as the genetic structuring of the raccoons. We isolated DNA from the roundworms using the method outlined in the DNA Minikit (Qiagen). Our research team isolated DNA from each roundworm sample and sent it to the Plant-Microbe Genomics Facility at The Ohio State University for gene amplification and sequencing. We built phylogenetic trees using these sequences, and compared these trees to some constructed for the raccoons. The correlations drawn between the raccoon and B. procyonis phylogenetic trees will help us better understand the relationship between the two species

    Baylisascaris procyonis Impacts Raccoon (Procyon lotor) Diets

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    Raccoons (Procyon lotor) are the definitive host for raccoon roundworms (Baylisascaris procyonis). Raccoon roundworm is responsible for a dangerous neurological disease known as larva migrans encephalopathy. Raccoons are omnivorous animals and rely on various food items. Dietary analyses help determine how a raccoon changes its diet in response to environmental features. Raccoons eat whatever food resource is most convenient and abundant. Parasite infections can potentially affect host eating habits in order to keep the host alive and active longer. In this study, we analyzed the diets of necropsied raccoons from ten townships of Clark and Greene Counties by examining their stomach contents. We categorized stomach contents by separating out plant material, vertebrate tissue, and invertebrate tissue. We measured the total stomach mass and the mass of plant material alone in order to compare and obtain a percentage of plant material in the raccoons’ diet. We conducted two chi-squared tests for equality of distributions. We tested the null hypotheses that raccoons from townships with high prevalence (\u3e60%) have the same vertebrate tissue and plant tissue prevalence as raccoons from townships with low roundworm prevalence
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