Evaluation of brain cholesterol metabolism after neonatal hypoxic-ischemic brain injury

Introduction Neonatal hypoxic-ischemic brain injury (HIBI), resulting from impaired cerebral blood flow and oxygen delivery to the brain, affects at least 1.5 per 1,000 live births each year in the United States. Altered levels of cholesterol and cholesterol metabolites have been identified in brain tissue and in serum after adult brain injury such as traumatic brain injury and stroke. We hypothesized that there would be temporal and brain region-specific alterations in cholesterol and sterol precursors after neonatal HIBI. Methods Postnatal day 9 CD1 mouse pups were anesthetized with isoflurane and randomized to HIBI induced by carotid artery ligation or controls receiving sham surgery consisting of dissection without ligation (n=24/group). Pups were allowed to recover after surgery and then placed in a hypoxia chamber at 8% oxygen for HIBI or 21% for controls for 30 minutes. Each group was further divided into three sub-groups (n=8/group) for blood and brain tissue collection at 30 minutes, 24 hours, or 72 hours after injury. Brain tissue was dissected into four regions: cortex, cerebellum, striatum/thalamus, and hippocampus. For each region, protein was quantified by BCA assay, interleukin-6 (IL-6) levels were measured by ELISA as a marker of injury severity, and liquid chromatography mass spectrometry was performed to evaluate for the following sterols: cholesterol, desmosterol, 7-dehydrocholesterol, 8-dehydrocholesterol, and lanosterol. Levels were compared between HIBI and control groups at each time point and neuroanatomical region. Additionally, the four samples in each group demonstrating the most severe injury, as defined by IL-6 levels, were stratified as “severe injury”. Differences were analyzed with a two-sided Mann-Whitney test. Results When assessing the entire cohort, no statistically significant differences were seen between HIBI and controls with respect to temporal or regional differences for any of the sterols measured. In animals with severe HIBI, however, cholesterol, 7-dehydrocholesterol, 8-dehydrocholesterol, and desmosterol were higher in the cortex at 24 hours after injury compared to controls. Additionally, desmosterol was also elevated in the cerebellum but decreased in the striatum 24 hours after injury in the severely injured animals. Conclusion Severe neonatal encephalopathy appears to be associated with alterations in cortical brain sterol levels, peaking around 24 hours after injury. Further defining the aberrations in brain metabolism in infants with HIBI could provide opportunities for not only diagnostic biomarkers but also the development of targeted therapies.https://digitalcommons.unmc.edu/chri_forum/1003/thumbnail.jp

Promoting and Protecting Against Stigma in Assisted Living and Nursing Homes

To determine the extent to which structures and processes of care in multilevel settings (independent living, assisted living, and nursing homes) result in stigma in assisted living and nursing homes

The Photon Underproduction Crisis

We examine the statistics of the low-redshift Lyman-alpha forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations from the Cosmic Origins Spectrograph (COS). We find that the value of the metagalactic photoionization rate required by our simulations to match the observed properties of the low-redshift Lyman-alpha forest is a factor of 5 larger than the value predicted by state-of-the art models for the evolution of this quantity. This mismatch results in the mean flux decrement of the Lyman-alpha forest being underpredicted by at least a factor of 2 (a 10-sigma discrepancy with observations) and a column density distribution of Lyman-alpha forest absorbers systematically and significantly elevated compared to observations over nearly two decades in column density. We examine potential resolutions to this mismatch and find that either conventional sources of ionizing photons (galaxies and quasars) must be significantly elevated relative to current observational estimates or our theoretical understanding of the low-redshift universe is in need of substantial revision.Comment: Submitted to ApJ Letters; 6 pages including 3 figure

The COS-Dwarfs Survey: The Carbon Reservoir Around sub-L* Galaxies

We report new observations of circumgalactic gas from the COS-Dwarfs survey, a systematic investigation of the gaseous halos around 43 low-mass z $\leq$ 0.1 galaxies using background QSOs observed with the Cosmic Origins Spectrograph. From the projected 1D and 2D distribution of C IV absorption, we find that C IV absorption is detected out to ~ 0.5 R$_{vir}$ of the host galaxies. The C IV absorption strength falls off radially as a power law and beyond 0.5 R$_{vir}$, no C IV absorption is detected above our sensitivity limit of ~ 50-100 m$\AA$. We find a tentative correlation between detected C IV absorption strength and star formation, paralleling the strong correlation seen in highly ionized oxygen for L~L* galaxies by the COS-Halos survey. The data imply a large carbon reservoir in the CGM of these galaxies, corresponding to a minimum carbon mass of $\gtrsim$ 1.2$\times 10^6$ $M_\odot$ out to ~ 110 kpc. This mass is comparable to the carbon mass in the ISM and more than the carbon mass currently in stars of these galaxies. The C IV absorption seen around these sub-L* galaxies can account for almost two-thirds of all $W_r$> 100 m$\AA$ C IV absorption detected at low z. Comparing the C IV covering fraction with hydrodynamical simulations, we find that an energy-driven wind model is consistent with the observations whereas a wind model of constant velocity fails to reproduce the CGM or the galaxy properties.Comment: 18 Pages, 11 Figures, ApJ 796 13

The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium

We analyze the physical conditions of the cool, photoionized (T $\sim 10^4$ K) circumgalactic medium (CGM) using the COS-Halos suite of gas column density measurements for 44 gaseous halos within 160 kpc of $L \sim L^*$ galaxies at $z \sim 0.2$. These data are well described by simple photoionization models, with the gas highly ionized (n$_{\rm HII}$/n$_{\rm H} \gtrsim 99\%$) by the extragalactic ultraviolet background (EUVB). Scaling by estimates for the virial radius, R$_{\rm vir}$, we show that the ionization state (tracked by the dimensionless ionization parameter, U) increases with distance from the host galaxy. The ionization parameters imply a decreasing volume density profile n$_{\rm H}$ = (10$^{-4.2 \pm 0.25}$)(R/R$_{\rm vir})^{-0.8\pm0.3}$. Our derived gas volume densities are several orders of magnitude lower than predictions from standard two-phase models with a cool medium in pressure equilibrium with a hot, coronal medium expected in virialized halos at this mass scale. Applying the ionization corrections to the HI column densities, we estimate a lower limit to the cool gas mass M$_{\rm CGM}^{\rm cool} > 6.5 \times 10^{10}$ M$_{\odot}$ for the volume within R $<$ R$_{\rm vir}$. Allowing for an additional warm-hot, OVI-traced phase, the CGM accounts for at least half of the baryons purported to be missing from dark matter halos at the 10$^{12}$ M$_{\odot}$ scale.Comment: 19 pages, 12 Figures, and a 37-page Appendix with 36 additional figures. Accepted to ApJ June 21 201

Volume 06

Introduction from Dean Dr. Charles Ross Caught Between Folklore and the Cold War: The Americanization of Russian Children\u27s Literature by Kristen Gains Graphic Design by Amanda Willis Graphic Design by Holly Backer Prejudices in Swiss German Accents by Monika Gutierrez Photography by Cara O\u27Neal Photography by Sara Nelson Edmund Tyrone\u27s Long Journey through Night by Sasha Silberman Photography by Jessica Beardsley Photography by Jamie Gardner and Edward Peeples The Republican Razor: The Guillotine as a Symbol of Equality by Jamie Clift Graphic Design by Matthew Sakach Genocide: The Lasting Effects of Gender Stratification in Rwanda By Tess Lione and Emily Wilkins Photography by Kelsey Holt and Jessica Page Morocco and the 20 February Movement by Charles Vancampen, Gilbert Hall, Jenny Nehrt, Kasey Dye, Amanda Tharp, Jamie Leeawrik, & Ashley McGee Photography by Emily Poulin Photography by Michael Kropf Improving Performance of Arbitrary Precision Arithmetic Using SIMD Assembly Code Instructions by Nick Pastore Art by Austin Polasky and Morgan Glasco Art by Laura L. Kahler The Effects of the Neutral Response Option on the Extremeness of Participant Responses by Melinda L. Edwards and Brandon C. Smith Graphic Design by Mariah Asbell Graphic Design by Cabell Edmunds College Bullying: An Exploratory Analysis by Amelia D. Perry Photography by Alyssa Hayes Death-Related Crime: Applying Bryant\u27s Conceptual Paradigm of Thanatological Crime to Military Settings by Irina Boothe Graphic Design by Perry Bason Graphic Design by James Earl

Astro2020 Must Issue Actionable Recommendations Regarding Diversity, Inclusion, and Harassment

The 2010 Decadal survey failed to issue any recommendations on diversity and inclusion.Astro2020 cannot make the same mistake. Findings can be ignored by funding agencies;recommendations cannot. In the past decade, multiple groups have assembled detailed actionplans to fix a broken climate within our profession. Astro2020 should play a key role, bysynthesizing this work to produce actionable recommendations to support diversity andinclusion and stop harassment within our profession

Stigma and Social Relations in a Dementia Care Unit

Dementia is a highly stigmatized and stigmatizing condition affecting more than one in eight older adults in the U.S. People with dementia have been characterized by American society as being not quite whole individuals; they are categorically different, the other. In long-term care (LTC) settings for older adults a high level of surveillance combines with existing prejudices against aging and decline. These settings create a microcosm of culture with the potential for heightened stigma against people perceived to be different, such as those with dementia. Some LTC settings include a dementia care unit (DCU), a separate level or unit designed specifically for people with dementia. DCUs have the potential to both exacerbate and shield residents with dementia from the stigmatizing attitudes of others. Utilizing qualitative research methods, this dissertation sought to address three specific aims examining: 1) the stigma of admission to and residence in a DCU in a multi-level LTC setting; 2) whether and how entry into and residence in a DCU affects residents' social relations; and 3) how staff, visitors, family, and other residents react to residents within a DCU. Ethnographic interviews were conducted with eighteen individuals including staff members, family members, and residents of the DCU over the course of ten months of participant observation. Analysis also included data from a previous study at the research site in order to retrospectively examine stigma. Evidence was found of stigmatizing attitudes toward DCU residents which manifested in lying to residents, the infantilization of residents, and the physical, psychological, and social separation of DCU residents from others at the setting. Many other aspects of stigma were identified and are discussed throughout this dissertation. In addition, residents of the DCU were found to recognize differences among each other and to react to one another on the basis of those differences. Although the DCU is envisioned as a safe, supportive environment for older adults with dementia, it falls short of this ideal. Inasmuch as the stigma against dementia remains part of the greater cultural and social environment, the DCU is likely to remain a stigmatized and stigmatizing setting for residents with dementia