154 research outputs found

    An Ideal Biodiesel Facility

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    Controlling greenhouse gas emissions and producing energy from renewable sources are two key components of energy sustainability movement. • Livestock manure is a large producer of greenhouse gases, but also has the potential to be a feedstock for energy production

    Comparison of low-dose CT with CT/CT fluoroscopy guidance in percutaneous sacral and supra-acetabular cementoplasty

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    PURPOSEPercutaneous cementoplasty is a minimally invasive treatment modality for painful osteoporotic and pathologic sacral and supra-acetabular iliac fractures. This study compares the use of low-dose CT guidance with CT/CT fluoroscopy in sacral and supra-acetabular cementoplasty.METHODSA retrospective review of patients who had undergone sacral or supra-acetabular cementoplasty was performed with patients grouped by use of CT/CT fluoroscopy or low-dose CT guidance during the procedure. Parameters evaluated included type of fracture, laterality of lesions, pain scores, pain medication use, imaging parameters, procedure time, dose-length product, effective dose, cement volume, and complications.RESULTSThere were 17 patients identified who underwent cementoplasty utilizing dual CT/CT fluoroscopy, while 13 patients had their procedures performed with low-dose CT. There was a statistically significant decrease in radiation dose in the low-dose CT group (1481 mGy·cm) compared with the CT/CT fluoroscopy group (2809 mGy·cm) (P = 0.013). There was a significant decrease in procedure time with low-dose CT for bilateral lesions (P = 0.016). There was no significant difference between groups in complication rate (P = 0.999). Clinically nonsignificant cement extravasation occurred in two patients (10%) in the CT/CT fluoroscopy group and in one patient (8%) in the low-dose CT group (P = 0.999). There was a significant decrease in pain scores compared with baseline on the visual analogue scale in both groups at 1 week (low-dose CT P = 0.002, CT/CT fluoroscopy P = 0.008) and 1 month postprocedure (low-dose CT P = 0.014, CT/CT fluoroscopy P = 0.004), but no difference between groups at 1 day (P = 0.196), 1 week (P = 0.368), or 1 month (P = 0.514).CONCLUSIONSacral and supra-acetabular cementoplasties can be performed safely and precisely using low-dose multiple-acquisition CT guidance while providing significant radiation dose reduction with no difference in extravasation rates, postprocedural pain reduction, and complications compared with CT/CT fluoroscopy

    Optimizing Two-Color Semiconductor Nanocrystal Immunoassays in Single Well Microtiter Plate Formats

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    The simultaneous detection of two analytes, chicken IgY (IgG) and Staphylococcal enterotoxin B (SEB), in the single well of a 96-well plate is demonstrated using luminescent semiconductor quantum dot nanocrystal (NC) tracers. The NC-labeled antibodies were prepared via sulfhydryl-reactive chemistry using a facile protocol that took <3 h. Dose response curves for each target were evaluated in a single immunoassay format and compared to Cy5, a fluorophore commonly used in fluorescent immunoassays, and found to be equivalent. Immunoassays were then performed in a duplex format, demonstrating multiplex detection in a single well with limits of detection equivalent to the single assay format: 9.8 ng/mL chicken IgG and 7.8 ng/mL SEB

    Simplistic Attachment and Multispectral Imaging with Semiconductor Nanocrystals

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    Advances in spectral deconvolution technologies are rapidly enabling researchers to replace or enhance traditional epifluorescence microscopes with instruments capable of detecting numerous markers simultaneously in a multiplexed fashion. While significantly expediting sample throughput and elucidating sample information, this technology is limited by the spectral width of common fluorescence reporters. Semiconductor nanocrystals (NC’s) are very bright, narrow band fluorescence emitters with great potential for multiplexed fluorescence detection, however the availability of NC’s with facile attachment chemistries to targeting molecules has been a severe limitation to the advancement of NC technology in applications such as immunocytochemistry and immunohistochemistry. Here we report the development of simple, yet novel attachment chemistries for antibodies onto NC’s and demonstrate how spectral deconvolution technology enables the multiplexed detection of 5 distinct NC-antibody conjugates with fluorescence emission wavelengths separated by as little as 20 nm

    Testing an inference of function from structure: Snake vertebrae do the twist

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    The zygapophyses and zygosphene–zygantrum articulations of snake vertebrae are hypothesized to restrict or eliminate vertebral torsion. This hypothesis is apparently based solely on the inference of function from structure, despite the limitations of such inferences, as well as contradictory observations and measurements. In this study, I observed and measured axial torsion in gopher snakes, Pituophis melanoleucus . To examine the structural basis of axial torsion, I measured the vertebral articulation angles along the body and the insertion angles of five epaxial muscles. To examine torsion in a natural behavior, I digitized video images and measured the degree of apparent axial torsion during terrestrial lateral undulation. Finally, I measured the mechanical capacity of the vertebral joints for actual torsion over intervals of 10 vertebrae in fresh, skinned segments of the trunk. Vertebral articulation angles vary up to 30° and are associated with variation in torsional capacity along the trunk. The freely crawling P. melanoleucus twisted up to 2.19° per vertebra, which produced substantial overall torsion when added over several vertebrae. The vertebral joints are mechanically capable of torsion up to 2.89° per joint. Therefore, despite the mechanical restriction imposed by the complex articulations, vertebral torsion occurs in snakes and appears to be functionally important in several natural behaviors. Even in cases in which mechanical function appears to be narrowly constrained by morphology, specific functions should not be inferred solely from structural analyses. J. Morphol. 241:217–225, 1999. © 1999 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34873/1/4_ftp.pd

    Individual fitness versus whole-crop photosynthesis:solar tracking tradeoffs in alfalfa

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    Despite the optimism of some molecular biologists, natural selection among the wild ancestors of crops is unlikely to have missed simple genetic improvements that would consistently have enhanced individual fitness. Tradeoff-free opportunities for further improvement of crop traits like photosynthetic efficiency or drought tolerance may therefore be elusive. Opportunities linked to acceptable tradeoffs may be abundant, however. Tradeoffs between individual competitiveness and the collective productivity of plant communities (e.g. those linked to height) have been key to past increases in yield potential. Solar tracking by leaves could involve such tradeoffs, if photosynthetic benefits to tracking leaves are outweighed by increased shading of leaves lower in the canopy. This hypothesis was tested using rotation in the horizontal plane to disrupt solar tracking in alfalfa. In sparse canopies, solar tracking increased net canopy photosynthesis, but rarely by more than 3%. As leaf area increased, solar tracking tended to decrease net canopy photosynthesis, despite edge effects in our 1-m2 artificial communities, which probably exaggerated net photosynthetic benefits of tracking. Computer modeling suggested that the season-long effects of solar tracking on community productivity can be negative. Solar tracking may have persisted, nonetheless, because individuals whose leaves track the sun increase shading of competitors

    Multi-ancestry meta-analysis of tobacco use disorder prioritizes novel candidate risk genes and reveals associations with numerous health outcomes

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    Tobacco use disorder (TUD) is the most prevalent substance use disorder in the world. Genetic factors influence smoking behaviors, and although strides have been made using genome-wide association studies (GWAS) to identify risk variants, the majority of variants identified have been for nicotine consumption, rather than TUD. We leveraged five biobanks to perform a multi-ancestral meta-analysis of TUD (derived via electronic health records, EHR) in 898,680 individuals (739,895 European, 114,420 African American, 44,365 Latin American). We identified 88 independent risk loci; integration with functional genomic tools uncovered 461 potential risk genes, primarily expressed in the brain. TUD was genetically correlated with smoking and psychiatric traits from traditionally ascertained cohorts, externalizing behaviors in children, and hundreds of medical outcomes, including HIV infection, heart disease, and pain. This work furthers our biological understanding of TUD and establishes EHR as a source of phenotypic information for studying the genetics of TUD
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