93 research outputs found
Cluster Analysis of Opioid Accessibility in the Carolinas Using Data from the ARCOS Database and an Enhanced Two-Step Floating Catchment Area Method
This study takes advantage of transaction level data from the U.S. Drug Enforcement Administration\u27s (DEA) Automation of Reports and Consolidated Orders System (ARCOS) database made newly available under court order by The Washington Post in July 2019. This data details individual shipments of pharmaceutical opioid analgesics from wholesalers to retail distributors. Using the Enhanced 2-Step Floating Catchment Area (E2SFCA) method, this study calculated access to opioid morphine milligram equivalents (MME) per capita for census tracts in North Carolina and South Carolina during the year 2009. This study demonstrated that outlier volumes of opioid analgesics at individual pharmacies are not always co-located with census tracts that have access to outlier per capita opioid volumes. In addition, this study used 5-year average American Community Survey (ACS) data to identify distinct populations and compare their access to opioid analgesics using a k-medoids clustering algorithm. While opioid access for most clusters corresponded to previous research, a rural, socially vulnerable African American population in the Low Country of both states was identified with high access to opioid analgesics. This finding is contrary to previous research, indicating the need for further investigation
Possible Detection of Cosmological Reionization Sources
We compare the available catalogs of galaxies in the Hubble
Ultra-Deep Field (UDF) and in the Great Observatories Origins Deep Survey
(GOODS) with the expected properties of the sources of cosmological
reionization from our previous theoretical study. Our approach is based on the
mean surface brightness of the sources required for reionization and depends on
relatively few undetermined parameters. We find that the observed mean surface
brightness of galaxies at is sufficient for reionization,
provided that the sources are composed of hot metal-free or metal-poor stars,
regardless of whether reionization occurs over a short or long interval of
redshift. The broad agreement between the new observations and our predictions
suggests that we may have detected the sources responsible for some or even all
of the reionization of hydrogen.Comment: ApJL in press. Slightly revised version (mostly wording and some
extra references). Original version submitted on 21-March-2004. 10 pages, 1
figur
Surficial geologic materials of the Cedar Rapids South Quadrangle
https://ir.uiowa.edu/igs_ofm/1005/thumbnail.jp
Surficial geologic materials of the Central City Quadrangle
https://ir.uiowa.edu/igs_ofm/1006/thumbnail.jp
Genotoxicity of multi-walled carbon nanotubes at occupationally relevant doses
Carbon nanotubes are commercially-important products of nanotechnology; however, their low density and small size makes carbon nanotube respiratory exposures likely during their production or processing. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to single-walled carbon nanotubes (SWCNT). In this study, we examined whether multi-walled carbon nanotubes (MWCNT) cause mitotic spindle damage in cultured cells at doses equivalent to 34 years of exposure at the NIOSH Recommended Exposure Limit (REL). MWCNT induced a dose responsive increase in disrupted centrosomes, abnormal mitotic spindles and aneuploid chromosome number 24 hours after exposure to 0.024, 0.24, 2.4 and 24 ÎŒg/cm2 MWCNT. Monopolar mitotic spindles comprised 95% of disrupted mitoses. Three-dimensional reconstructions of 0.1 ÎŒm optical sections showed carbon nanotubes integrated with microtubules, DNA and within the centrosome structure. Cell cycle analysis demonstrated a greater number of cells in S-phase and fewer cells in the G2 phase in MWCNT-treated compared to diluent control, indicating a G1/S block in the cell cycle. The monopolar phenotype of the disrupted mitotic spindles and the G1/S block in the cell cycle is in sharp contrast to the multi-polar spindle and G2 block in the cell cycle previously observed following exposure to SWCNT. One month following exposure to MWCNT there was a dramatic increase in both size and number of colonies compared to diluent control cultures, indicating a potential to pass the genetic damage to daughter cells. Our results demonstrate significant disruption of the mitotic spindle by MWCNT at occupationally relevant exposure levels
A negative feedback loop mediated by the Bcl6-cullin 3 complex limits Tfh cell differentiation
Induction of Bcl6 (B cell lymphoma 6) is essential for T follicular helper (Tfh) cell differentiation of antigen-stimulated CD4(+) T cells. Intriguingly, we found that Bcl6 was also highly and transiently expressed during the CD4(+)CD8(+) (double positive [DP]) stage of T cell development, in association with the E3 ligase cullin 3 (Cul3), a novel binding partner of Bcl6 which ubiquitinates histone proteins. DP stage-specific deletion of the E3 ligase Cul3, or of Bcl6, induced the derepression of the Bcl6 target genes Batf (basic leucine zipper transcription factor, ATF-like) and Bcl6, in part through epigenetic modifications of CD4(+) single-positive thymocytes. Although they maintained an apparently normal phenotype after emigration, they expressed increased amounts of Batf and Bcl6 at basal state and produced explosive and prolonged Tfh responses upon subsequent antigen encounter. Ablation of Cul3 in mature CD4(+) splenocytes also resulted in dramatically exaggerated Tfh responses. Thus, although previous studies have emphasized the essential role of Bcl6 in inducing Tfh responses, our findings reveal that Bcl6-Cul3 complexes also provide essential negative feedback regulation during both thymocyte development and T cell activation to restrain excessive Tfh responses
Far-Infrared detection of methylene
We present a clear detection of CH2 in absorption towards the molecular cloud
complexes Sagittarius B2 and W49 N using the ISO Long Wavelength Spectrometer.
These observations represent the first detection of its low excitation
rotational lines in the interstellar medium. Towards Sagittarius B2, we detect
both ortho and para transitions allowing a determination of the total CH2
column density of N(CH2)=(7.5+/-1.1)x10^14 cm^-2. We compare this with the
related molecule, CH, to determine [CH/CH2]=2.7+/-0.5. Comparison with chemical
models shows that the CH abundance along the line of sight is consistent with
diffuse cloud conditions and that the high [CH/CH2] ratio can be explained by
including the effect of grain-surface reactions.Comment: 11 pages, 4 figures, accepted for publication in A&
Activation and Deactivation of a Robust Immobilized Cp*Ir-Transfer Hydrogenation Catalyst: A Multielement in Situ X-ray Absorption Spectroscopy Study
A highly robust immobilized [Cp*IrCl2]2 precatalyst on Wang resin for transfer hydrogenation, which can be recycled up to 30 times, was studied using a novel combination of X-ray absorption spectroscopy (XAS) at Ir L3-edge, Cl K-edge, and K K-edge. These culminate in in situ XAS experiments that link structural changes of the Ir complex with its catalytic activity and its deactivation. Mercury poisoning and âhot filtrationâ experiments ruled out leached Ir as the active catalyst. Spectroscopic evidence indicates the exchange of one chloride ligand with an alkoxide to generate the active precatalyst. The exchange of the second chloride ligand, however, leads to a potassium alkoxideâiridate species as the deactivated form of this immobilized catalyst. These findings could be widely applicable to the many homogeneous transfer hydrogenation catalysts with Cp*IrCl substructure
Research on information systems failures and successes: Status update and future directions
The final publication is available at Springer via http://dx.doi.org/10.1007/s10796-014-9500-yInformation systems success and failure are among the most prominent streams in IS research. Explanations of why some IS fulfill their expectations, whereas others fail, are complex and multi-factorial. Despite the efforts to understand the underlying factors, the IS failure rate remains stubbornly high. A Panel session was held at the IFIP Working Group 8.6 conference in Bangalore in 2013 which forms the subject of this Special Issue. Its aim was to reflect on the need for new perspectives and research directions, to provide insights and further guidance for managers on factors enabling IS success and avoiding IS failure. Several key issues emerged, such as the need to study problems from multiple perspectives, to move beyond narrow considerations of the IT artifact, and to venture into underexplored organizational contexts, such as the public sector. © 2014 Springer Science+Business Media New York
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