351 research outputs found
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Polarizing beam splitter cube for circularly and elliptically polarized light
A method of designing an arbitrary polarizing beam splitter (PBS) cube using multiple layers of thin-film liquid crystal polymer is demonstrated. This methodology utilizes cholesteric phase liquid crystal polymer (Ch-LCP) to transmit one handedness of elliptically polarized light and reflect the orthogonal state when unpolarized light is incident. Using additional nematic liquid crystal polymer layers, the polarization state for the transmitted and reflected light can be controlled and output to any two orthogonal states represented on the Poincarte sphere. Two cubes are designed, fabricated, tested, and compared with theory. One cube is constructed with a single layer of Ch-LCP, and another cube is constructed with a layer of Ch-LCP and an additional nematic liquid crystal polymer layer.National Science Foundation (NSF) [1607358]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
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Effects of X-Linkage and Sex-Biased Gene Expression on the Rate of Adaptive Protein Evolution in Drosophila
Patterns of polymorphism and divergence in Drosophila protein-coding genes suggest that a considerable fraction of amino acid differences between species can be attributed to positive selection and that genes with sex-biased expression, that is, those expressed predominantly in one sex, have especially high rates of adaptive evolution. Previous studies, however, have been restricted to autosomal sex-biased genes and, thus, do not provide a complete picture of the evolutionary forces acting on sex-biased genes across the genome. To determine the effects of X-linkage on sex-biased gene evolution, we surveyed DNA sequence polymorphism and divergence in 45 X-linked genes, including 17 with male-biased expression, 13 with female-biased expression, and 15 with equal expression in the 2 sexes. Using both single- and multilocus tests for selection, we found evidence for adaptive evolution in both groups of sex-biased genes. The signal of adaptive evolution was particularly strong for X-linked male-biased genes. A comparison with data from 91 autosomal genes revealed a ‘‘fast-X’’ effect, in which the rate of adaptive evolution was greater for X-linked than for autosomal genes. This effect was strongest for male-biased genes but could be seen in the other groups as well. A genome-wide analysis of coding sequence divergence that accounted for sex-biased expression also uncovered a fast-X effect for male-biased and unbiased genes, suggesting that recessive beneficial mutations play an important role in adaptation.Organismic and Evolutionary Biolog
X-33 Metallic TPS Tests in NASA-LaRC High Temperature Tunnel
Conclusions The first series of metallic TPS tests in the NASA-LaRC Mach 7 High Temperature Tunnel has been completed. Additional testing is 'in progress and shall provide data for off-design configurations for the metallic TPS. The available data are being analyzed and being used to correlate analytical models to be used for X-33 flight design analysis. The final paper shan present additional data from these tests and comparisons between the data and analytical predictions
Direct assessment of mental health and metabolic syndrome amongst Indonesian adolescents: a study design for a mixed-methods study sampled from school and community settings
Non-communicable diseases (NCDs) are the leading cause of morbidity and mortality globally, with the burden largely borne by people living in low- and middle-income countries. Adolescents are central to NCD control through the potential to modify risks and alter the trajectory of these diseases across the life-course. However, an absence of epidemiological data has contributed to the relative exclusion of adolescents from policies and responses. This paper documents the design of a study to measure the burden of metabolic syndrome (a key risk for NCDs) and poor mental health (a key outcome) amongst Indonesian adolescents. Using a mixed-method design, we sampled 16–18-year-old adolescents from schools and community-based settings across Jakarta and South Sulawesi. Initial formative qualitative enquiry used focus group discussions to understand how young people conceptualise mental health and body weight (separately); what they perceive as determinants of these NCDs; and what responses to these NCDs should involve. These findings informed the design of a quantitative survey that adolescents selfcompleted electronically. Mental health was measured using the Centre for Epidemiologic Studies Depression Scale-Revised (CESD-R) and Kessler-10 (both validated against formal psychiatric interview in a subsample), with the metabolic syndrome measured using biomarkers and anthropometry. The survey also included scales relating to victimisation, connectedness, selfefficacy, body image and quality of life. Adolescents were sampled from schools using a multistage cluster design, and from the community using respondent-driven sampling (RDS). This study will substantially advance the field of NCD measurement amongst adolescents, especially in settings like Indonesia. It demonstrates that high quality, objective measurement is acceptable and feasible, including the collection of biomarkers in a school-based setting. It demonstrates how comparable data can be collected across both in-school and out of school adolescents, allowing a more comprehensive measure of NCD burden, risk and correlate
Statistical Inference of Selection and Divergence from a Time-Dependent Poisson Random Field Model
We apply a recently developed time-dependent Poisson random field model to aligned DNA sequences from two related biological species to estimate selection coefficients and divergence time. We use Markov chain Monte Carlo methods to estimate species divergence time and selection coefficients for each locus. The model assumes that the selective effects of non-synonymous mutations are normally distributed across genetic loci but constant within loci, and synonymous mutations are selectively neutral. In contrast with previous models, we do not assume that the individual species are at population equilibrium after divergence. Using a data set of 91 genes in two Drosophila species, D. melanogaster and D. simulans, we estimate the species divergence time (or 1.68 million years, assuming the haploid effective population size years) and a mean selection coefficient per generation . Although the average selection coefficient is positive, the magnitude of the selection is quite small. Results from numerical simulations are also presented as an accuracy check for the time-dependent model
MitoQ improves mitochondrial dysfunction in heart failure induced by pressure overload.
Heart failure remains a major public-health problem with an increase in the number of patients worsening from this disease. Despite current medical therapy, the condition still has a poor prognosis. Heart failure is complex but mitochondrial dysfunction seems to be an important target to improve cardiac function directly. Our goal was to analyze the effects of MitoQ (100 µM in drinking water) on the development and progression of heart failure induced by pressure overload after 14 weeks. The main findings are that pressure overload-induced heart failure in rats decreased cardiac function in vivo that was not altered by MitoQ. However, we observed a reduction in right ventricular hypertrophy and lung congestion in heart failure animals treated with MitoQ. Heart failure also decreased total mitochondrial protein content, mitochondrial membrane potential in the intermyofibrillar mitochondria. MitoQ restored membrane potential in IFM but did not restore mitochondrial protein content. These alterations are associated with the impairment of basal and stimulated mitochondrial respiration in IFM and SSM induced by heart failure. Moreover, MitoQ restored mitochondrial respiration in heart failure induced by pressure overload. We also detected higher levels of hydrogen peroxide production in heart failure and MitoQ restored the increase in ROS production. MitoQ was also able to improve mitochondrial calcium retention capacity, mainly in the SSM whereas in the IFM we observed a small alteration. In summary, MitoQ improves mitochondrial dysfunction in heart failure induced by pressure overload, by decreasing hydrogen peroxide formation, improving mitochondrial respiration and improving mPTP opening
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