245 research outputs found

    Three dimensional optic tissue culture and process

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    A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioreactor at low shear conditions. The tissue forms normal, functional tissue organization and extracellular matrix

    Relationships of Polychlorinated Biphenyls and Dichlorodiphenyldichloroethylene (p,pā€™-DDE) with Testosterone Levels in Adolescent Males

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    Background: Concern persists over endocrine-disrupting effects of persistent organic pollutants (POPs) on human growth and sexual maturation. Potential effects of toxicant exposures on testosterone levels during puberty are not well characterized. Objectives: In this study we evaluated the relationship between toxicants [polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,pĀ“-DDE), hexachlorobenzene (HCB), and lead] and testosterone levels among 127 Akwesasne Mohawk males 10 to \u3c 17 years of age with documented toxicant exposures. Methods: Data were collected between February 1996 and January 2000. Fasting blood specimens were collected before breakfast by trained Akwesasne Mohawk staff. Multivariable regression models were used to estimates associations between toxicants and serum testosterone, adjusted for other toxicants, Tanner stage, and potential confounders. Results: The sum of 16 PCB congeners (Ī£16PCBs) that were detected in ā‰„ 50% of the population was significantly and negatively associated with serum testosterone levels, such that a 10% change in exposure was associated with a 5.6% decrease in testosterone (95% CI: ā€“10.8, ā€“0.5%). Of the 16 congeners, the more persistent ones (Ī£8PerPCBs) were related to testosterone, whereas the less persistent ones, possibly reflecting more recent exposure, were not. When PCB congeners were subgrouped, the association was significant for the sum of eight more persistent PCBs (5.7% decrease; 95% CI: ā€“11, ā€“0.4%), and stronger than the sum of six less persistent congeners (3.1% decrease; 95% CI: ā€“7.2, 0.9%). p,pĀ“-DDE was positively but not significantly associated with serum testosterone (5.2% increase with a 10% increase in exposure; 95% CI: ā€“0.5, 10.9%). Neither lead nor HCB was significantly associated with testosterone levels. Conclusions: Exposure to PCBs, particularly the more highly persistent congeners, may negatively influence testosterone levels among adolescent males. The positive relationship between p,pĀ“-DDE and testosterone indicates that not all POPs act similarly

    Elevated atmospheric [CO2] can dramatically increase wheat yields in semi-arid environments and buffer against heat waves

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    Wheat production will be impacted by increasing concentration of atmospheric CO2 [CO2], which is expected to rise from about 400 Ī¼mol molāˆ’1 in 2015 to 550 Ī¼mol molāˆ’1 by 2050. Changes to plant physiology and crop responses from elevated [CO2] (e[CO2]) are well documented for some environments, but field-level responses in dryland Mediterranean environments with terminal drought and heat waves are scarce. The Australian Grains Free Air CO2 Enrichment facility was established to compare wheat (Triticum aestivum) growth and yield under ambient (~370 Ī¼molāˆ’1 in 2007) and e[CO2] (550 Ī¼molāˆ’1) in semi-arid environments. Experiments were undertaken at two dryland sites (Horsham and Walpeup) across three years with two cultivars, two sowing times and two irrigation treatments. Mean yield stimulation due to e[CO2] was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%, depending on environment. Under supplemental irrigation, e[CO2] stimulated yields at Horsham by 37% compared to 13% under rainfed conditions, showing that water limited growth and yield response to e[CO2]. Heat wave effects were ameliorated under e[CO2] as shown by reductions of 31% and 54% in screenings and 10% and 12% larger kernels (Horsham and Walpeup). Greatest yield stimulations occurred in the e[CO2] late sowing and heat stressed treatments, when supplied with more water. There were no clear differences in cultivar response due to e[CO2]. Multiple regression showed that yield response to e[CO2] depended on temperatures and water availability before and after anthesis. Thus, timing of temperature and water and the crop's ability to translocate carbohydrates to the grain postanthesis were all important in determining the e[CO2] response. The large responses to e[CO2] under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing climate

    Elevated atmospheric [CO<sub>2</sub>] can dramatically increase wheat yields in semi-arid environments and buffer against heat waves

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    Tausz, M ORCiD: 0000-0001-8205-8561Wheat production will be impacted by increasing concentration of atmospheric CO2 [CO2], which is expected to rise from about 400 Ī¼mol mol-1 in 2015 to 550 Ī¼mol mol-1 by 2050. Changes to plant physiology and crop responses from elevated [CO2] (e[CO2]) are well documented for some environments, but field-level responses in dryland Mediterranean environments with terminal drought and heat waves are scarce. The Australian Grains Free Air CO2 Enrichment facility was established to compare wheat (Triticum aestivum) growth and yield under ambient (~370 Ī¼mol-1 in 2007) and e[CO2] (550 Ī¼mol-1) in semi-arid environments. Experiments were undertaken at two dryland sites (Horsham and Walpeup) across three years with two cultivars, two sowing times and two irrigation treatments. Mean yield stimulation due to e[CO2] was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%, depending on environment. Under supplemental irrigation, e[CO2] stimulated yields at Horsham by 37% compared to 13% under rainfed conditions, showing that water limited growth and yield response to e[CO2]. Heat wave effects were ameliorated under e[CO2] as shown by reductions of 31% and 54% in screenings and 10% and 12% larger kernels (Horsham and Walpeup). Greatest yield stimulations occurred in the e[CO2] late sowing and heat stressed treatments, when supplied with more water. There were no clear differences in cultivar response due to e[CO2]. Multiple regression showed that yield response to e[CO2] depended on temperatures and water availability before and after anthesis. Thus, timing of temperature and water and the crop's ability to translocate carbohydrates to the grain postanthesis were all important in determining the e[CO2] response. The large responses to e[CO2] under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing climate. Ā© 2016 John Wiley & Sons Ltd

    Production of Ļ€0\pi^0 and Ī·\eta mesons in U++U collisions at sNN=192\sqrt{s_{_{NN}}}=192 GeV

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    The PHENIX experiment at the Relativistic Heavy Ion Collider measured Ļ€0\pi^0 and Ī·\eta mesons at midrapidity in U++U collisions at sNN=192\sqrt{s_{_{NN}}}=192 GeV in a wide transverse momentum range. Measurements were performed in the Ļ€0(Ī·)ā†’Ī³Ī³\pi^0(\eta)\rightarrow\gamma\gamma decay modes. A strong suppression of Ļ€0\pi^0 and Ī·\eta meson production at high transverse momentum was observed in central U++U collisions relative to binary scaled pp++pp results. Yields of Ļ€0\pi^0 and Ī·\eta mesons measured in U++U collisions show similar suppression pattern to the ones measured in Au++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV for similar numbers of participant nucleons. The Ī·\eta/Ļ€0\pi^0 ratios do not show dependence on centrality or transverse momentum, and are consistent with previously measured values in hadron-hadron, hadron-nucleus, nucleus-nucleus, and e+eāˆ’e^+e^- collisions.Comment: 403 authors from 72 institutions, 13 pages, 6 figures, 7 tables, 2012 data. v2 is version accepted by Physical Review C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    An Exo-Kuiper Belt with an Extended Halo around HD 191089 in Scattered Light

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    We have obtained Hubble Space Telescope STIS and NICMOS and Gemini/GPI scattered-light images of the HD 191089 debris disk. We identify two spatial components: a ring resembling the Kuiper Belt in radial extent (FWHM āˆ¼ 25 au, centered at āˆ¼46 au) and a halo extending to āˆ¼640 au. We find that the halo is significantly bluer than the ring, consistent with the scenario that the ring serves as the birth ring for the smaller dust in the halo. We measure the scattering phase functions in the 30Ā°-150Ā° scattering-angle range and find that the halo dust is more forward- and backward-scattering than the ring dust. We measure a surface density power-law index of -0.68 Ā± 0.04 for the halo, which indicates the slowdown of the radial outward motion of the dust. Using radiative transfer modeling, we attempt to simultaneously reproduce the (visible) total and (near-infrared) polarized intensity images of the birth ring. Our modeling leads to mutually inconsistent results, indicating that more complex models, such as the inclusion of more realistic aggregate particles, are needed
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