1,501 research outputs found

    The Enduring Appeal of Community Schools

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    Use of a Novel Infrared Wavelength-tunable Laser Mueller-matrix Polarimetric Scatterometer to Measure Nanostructured Optical Materials

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    Nanostructured optical materials, for example, metamaterials, have unique spectral, directional, and polarimetric properties. Samples designed and fabricated for infrared (IR) wavelengths have been characterized using broadband instruments to measure specular polarimetric transmittance or reflectance as in ellipsometry or integrated hemisphere transmittance or reflectance. We have developed a wavelength-tunable IR Mueller-matrix (Mm) polarimetric scatterometer which uses tunable external-cavity quantum-cascade lasers (EC-QCLs) to tune onto and off of the narrowband spectral resonances of nanostructured optical materials and performed full polarimeteric and directional evaluation to more fully characterize their behavior. Using a series of EC-QCLs, the instrument is tunable over 4.37-6.54 μm wavelengths in the mid-wave IR and 7.41-9.71 μm in the long-wave IR and makes measurements both at specular angles, acting as a Mm polarimeter, and at off-specular angles, acting as a Mm scatterometer. Example measurements of an IR thermal metamaterial are shown

    Association of low level viremia with inflammation and mortality in HIV-infected adults.

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    BackgroundWhether HIV viremia, particularly at low levels is associated with inflammation, increased coagulation, and all-cause mortality is unclear.MethodsThe associations of HIV RNA level with C-reactive protein (CRP), fibrinogen, interleukin (IL)-6 and mortality were evaluated in 1116 HIV-infected participants from the Study of Fat Redistribution and Metabolic Change in HIV infection. HIV RNA level was categorized as undetectable (i.e., "target not detected"), 1-19, 20-399, 400-9999, and ≥ 10,000 copies/ml. Covariates included demographics, lifestyle, adipose tissue, and HIV-related factors.ResultsHIV RNA level had little association with CRP. Categories of HIV RNA below 10,000 copies/ml had similar levels of IL-6 compared with an undetectable HIV RNA level, while HIV RNA ≥ 10,000 copies/ml was associated with 89% higher IL-6 (p<0.001). This association was attenuated by ~50% after adjustment for CD4+ cell count. Higher HIV RNA was associated with higher fibrinogen. Compared to an undetectable HIV RNA level, fibrinogen was 0.6%, 1.9%, 4.5%, 4.6%, and 9.4% higher across HIV RNA categories, respectively, and statistically significant at the highest level (p = 0.0002 for HIV RNA ≥ 10,000 copies/ml). Higher HIV RNA was associated with mortality during follow-up in unadjusted analysis, but showed little association after adjustment for CD4+ cell count and inflammation.ConclusionHIV RNA ≥ 10,000 copies/ml was associated with higher IL-6 and fibrinogen, but lower levels of viremia appeared similar, and there was little association with CRP. The relationship of HIV RNA with IL-6 was strongly affected by CD4 cell depletion. After adjustment for CD4+ cell count and inflammation, viremia did not appear to be substantially associated with mortality risk over 5 years

    Construction and composition of the squid pen from Doryteuthis pealeii

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    Author Posting. © University of Chicago Press, 2019. This article is posted here by permission of University of Chicago Press for personal use, not for redistribution. The definitive version was published in Messerli, M. A., Raihan, M. J., Kobylkevich, B. M., Benson, A. C., Bruening, K. S., Shribak, M., Rosenthal, J. J. C., & Sohn, J. J. Construction and composition of the squid pen from Doryteuthis pealeii. Biological Bulletin. 237(1), (2019): 1-15, doi:10.1086/704209.The pen, or gladius, of the squid is an internalized shell. It serves as a site of attachment for important muscle groups and as a protective barrier for the visceral organs. The pen’s durability and flexibility are derived from its unique composition of chitin and protein. We report the characterization of the structure, development, and composition of pens from Doryteuthis pealeii. The nanofibrils of the polysaccharide β-chitin are arranged in an aligned configuration in only specific regions of the pen. Chitin is secreted early in development, enabling us to characterize the changes in pen morphology prior to hatching. The chitin and proteins are assembled in the shell sac surrounded by fluid that has a significantly different ionic composition from squid plasma. Two groups of proteins are associated with the pen: those on its surface and those embedded within the pen. Only 20 proteins are identified as embedded within the pen. Embedded proteins are classified into six groups, including chitin associated, protease, protease inhibitors, intracellular, extracellular matrix, and those that are unknown. The pen proteins share many conserved domains with proteins from other chitinous structures. We conclude that the pen is one of the least complex, load-bearing, chitin-rich structures currently known and is amenable to further studies to elucidate natural construction mechanisms using chitin and protein.We thank John Dowling for financial support. We thank Kasia Hammar and Louie Kerr of the Marine Biological Laboratory Central Microscopy Facility for help obtaining scanning electron micrographs. We thank Bogdan Budnik and Renee Robinson from the Mass Spectrometry and Proteomics Resource Laboratory for their help and advice with protein identification. We thank Shin-Yi Marzano and Chenchen Feng of South Dakota State University for help with rapid amplification of cDNA ends. Funding for this work was provided by the Eugene and Millicent Bell Fellowship Fund in Tissue Engineering (MAM), an Agriculture and Biological Sciences Undergraduate Research Award (KSB), National Institutes of Health grant R01 GM101701 (MS), National Science Foundation grant IOS1557748 (JJCR), and Israel-United States Binational Science Foundation 2013094 (JJCR). Literature Cited2020-07-0

    Design for producing fiberglass fabric in a lunar environment

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    The purpose of this project was to design a method of producing a fabric material on the lunar surface from readily available glass fibers. Various methods for forming fabrics were analyzed to determine which methods were appropriate for the lunar conditions. A nonwoven process was determined to be the most suitable process for making a fabric material out of fiberglass under these conditions. Various resins were considered for adhering the fibers. A single thermoplastic resin (AURUM) was found to be the only applicable resin. The end product of the process was determined to be suitable for use as a roadway surfacing material, canopy material, reflective material, or packaging material. A cost analysis of the lunar process versus shipping the end-product from the Earth suggests that the lunar formation is highly feasible. A design for a lunar, nonwoven process was determined and is included

    Discovery of a Powerful >1061 erg AGN Outburst in the Distant Galaxy Cluster SPT-CLJ0528-5300

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    We present ~103 ks of Chandra observations of the galaxy cluster SPT-CLJ0528-5300 (SPT0528, z = 0.768). This cluster harbors the most radio-loud (L 1.4GHz = 1.01 × 1033 erg s−1 Hz−1) central active galactic nucleus (AGN) of any cluster in the South Pole Telescope (SPT) Sunyaev–Zeldovich survey with available X-ray data. We find evidence of AGN-inflated cavities in the X-ray emission, which are consistent with the orientation of the jet direction revealed by Australia Telescope Compact Array radio data. The combined probability that two such depressions—each at ~1.4–1.8σ significance, oriented ~180° apart and aligned with the jet axis—would occur by chance is 0.1%. At gsim1061 erg, the outburst in SPT0528 is among the most energetic known in the universe, and certainly the most powerful known at z > 0.25. This work demonstrates that such powerful outbursts can be detected even in shallow X-ray exposures out to relatively high redshifts (z ~ 0.8), providing an avenue for studying the evolution of extreme AGN feedback. The ratio of the cavity power (Pcav=(9.4±5.8)×1045{P}_{\mathrm{cav}}=(9.4\pm 5.8)\times {10}^{45} erg s−1) to the cooling luminosity (L cool = (1.5 ± 0.5) × 1044 erg s−1) for SPT0528 is among the highest measured to date. If, in the future, additional systems are discovered at similar redshifts with equally high P cav/L cool ratios, it would imply that the feedback/cooling cycle was not as gentle at high redshifts as in the low-redshift universe
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