Thermostructural applications of heat pipes

The feasibility of integrating heat pipes in high temperature structure to reduce local hot spot temperature was evaluated for a variety of hypersonic aerospace vehicles. From an initial list of twenty-two potential applications, the single stage to orbit wing leading edge showed the greatest promise and was selected for preliminary design of an integrated heat pipe thermostructural system. The design consisted of a Hastelloy X assembly with sodium heat pipe passages aligned normal to the wing leading edge. A d-shaped heat pipe cross section was determined to be optimum from the standpoint of structural weight

Artificial atmosphere control system

Two-gas control system has been developed which uses existing hardware. Three systems are used for control, monitoring, and safety backup. Pure oxygen will be supplied to maintain safe pressure level should something go wrong

Trabue, Alias Punta Gorda

The Florida Southern Railway in 1885-1886, constructed a line from Bartow Junction to Charlotte Harbor, and a new town, Punta Gorda, sprang up at the southern terminus of what was then the southernmost railroad in the United States. Punta Gorda’s beginning enbroiled its settlers and leading citizens in a controversy that raged for many years

The Mass of the Black Hole in the Quasar PG 2130+099

We present the results of a recent reverberation-mapping campaign undertaken to improve measurements of the radius of the broad line region and the central black hole mass of the quasar PG 2130+099. Cross correlation of the 5100 angstrom continuum and H-beta emission-line light curves yields a time lag of 22.9 (+4.4 - 4.3) days, corresponding to a central black hole mass MBH= 3.8 (+/- 1.5) x 10^7 Msun. This value supports the notion that previous measurements yielded an incorrect lag. We re-analyzed previous datasets to investigate the possible sources of the discrepancy and conclude that previous measurement errors were apparently caused by a combination of undersampling of the light curves and long-term secular changes in the H-beta emission-line equivalent width. With our new measurements, PG 2130+099 is no longer an outlier in either the R-L or the MBH-Sigma relationships.Comment: 21 pages, 7 figures; Accepted for publication in Ap

Keck Observations of the Young Metal-Poor Host Galaxy of the Super-Chandrasekhar-Mass Type Ia Supernova SN 2007if

We present Keck LRIS spectroscopy and $g$-band photometry of the metal-poor, low-luminosity host galaxy of the super-Chandrasekhar mass Type Ia supernova SN 2007if. Deep imaging of the host reveals its apparent magnitude to be $m_g=23.15\pm0.06$, which at the spectroscopically-measured redshift of $z_{helio}=0.07450\pm0.00015$ corresponds to an absolute magnitude of $M_g=-14.45\pm0.06$. Galaxy $g-r$ color constrains the mass-to-light ratio, giving a host stellar mass estimate of $\log(M_*/M_\odot)=7.32\pm0.17$. Balmer absorption in the stellar continuum, along with the strength of the 4000\AA\ break, constrain the age of the dominant starburst in the galaxy to be $t_\mathrm{burst}=123^{+165}_{-77}$ Myr, corresponding to a main-sequence turn-off mass of $M/M_\odot=4.6^{+2.6}_{-1.4}$. Using the R$_{23}$ method of calculating metallicity from the fluxes of strong emission lines, we determine the host oxygen abundance to be $12+\log(O/H)_\mathrm{KK04}=8.01\pm0.09$, significantly lower than any previously reported spectroscopically-measured Type Ia supernova host galaxy metallicity. Our data show that SN 2007if is very likely to have originated from a young, metal-poor progenitor.Comment: 15 pages, 9 figures; accepted for publication in Ap

Relationship between miR-335 and sterol levels after in vitro hypoxia-ischemia of primary brain cells

Background/Purpose: Cholesterol homeostasis is vital for synaptogenesis and myelination during fetal and neonatal brain development. Both brain and plasma sterol levels have been shown to be associated with outcomes in adult stroke, and animal studies have suggested brain and plasma sterol changes in neonatal hypoxic-ischemic brain injury. MicroRNA-335 (miR-335) has been associated with brain sterol metabolism and our preliminary data showed that sterol metabolism is dysregulated in the brain after hypoxic-ischemic injury in a mouse model. This study sought to describe the effect of oxygen-glucose deprivation in vitro on individual brain cell populations and to validate the associations between sterol levels and miR-335 levels. Lastly, we assessed the feasibility of transfecting miR-335 mimics or miRNA antagonists (antagomiRs) in these brain cell cultures to set up future experiments to alter miR-335 levels for neuroprotection. Methods: Primary cells were isolated from embryonic day 18 CD1 mouse brains. Cells were maintained in DMEM for mixed glial culture and Neurobasal media with B27 for neurons. Once astrocytes were confluent, microglia were separated from the mixed glial culture by shaking to provide pure cell populations. Each of the three cell types underwent oxygen and glucose deprivation (OGD: glucose/pyruvate/B27-free media, 1% O2, 5% CO2) for 4 hours followed by replacement of glucose/pyruvate/B27 and resumption of normoxia. At 24 hours after OGD, cells (n=12 wells OGD and 12 normoxia) were washed, counted, and sterols analyzed by LC-MS/MS, normalized to the number of cells/well. Additional cells underwent measurement of miR-335 expression using quantitative PCR and/or transfection with miR-335 mimic or antagomiR. Results: Although lanosterol is increased after OGD in neurons, desmosterol and cholesterol levels were decreased. In microglia and astrocytes, cholesterol levels were lower than in neurons but increased after OGD. MiR-335 expression in neurons and astrocytes were inverse to cholesterol level changes, though this association was not seen in microglia. Lastly, red fluorescent protein-labelled miR-335 mimic was visualized in both neurons and astrocytes after transfection and miR-335 expression changes were seen after transfection in astrocytes. Conclusions: Sterol levels are altered after OGD and may be associated with OGD changes. Transfection of miR-335 mimic and antagomiR is feasible and future studies using these tools will allow for better understanding of the effects of neonatal HIBI on sterol levels. This approach could allow for identification of targets to aid in developing therapeutics.https://digitalcommons.unmc.edu/chri_forum/1017/thumbnail.jp

Identification and characterization of a novel non-structural protein of bluetongue virus

Bluetongue virus (BTV) is the causative agent of a major disease of livestock (bluetongue). For over two decades, it has been widely accepted that the 10 segments of the dsRNA genome of BTV encode for 7 structural and 3 non-structural proteins. The non-structural proteins (NS1, NS2, NS3/NS3a) play different key roles during the viral replication cycle. In this study we show that BTV expresses a fourth non-structural protein (that we designated NS4) encoded by an open reading frame in segment 9 overlapping the open reading frame encoding VP6. NS4 is 77–79 amino acid residues in length and highly conserved among several BTV serotypes/strains. NS4 was expressed early post-infection and localized in the nucleoli of BTV infected cells. By reverse genetics, we showed that NS4 is dispensable for BTV replication in vitro, both in mammalian and insect cells, and does not affect viral virulence in murine models of bluetongue infection. Interestingly, NS4 conferred a replication advantage to BTV-8, but not to BTV-1, in cells in an interferon (IFN)-induced antiviral state. However, the BTV-1 NS4 conferred a replication advantage both to a BTV-8 reassortant containing the entire segment 9 of BTV-1 and to a BTV-8 mutant with the NS4 identical to the homologous BTV-1 protein. Collectively, this study suggests that NS4 plays an important role in virus-host interaction and is one of the mechanisms played, at least by BTV-8, to counteract the antiviral response of the host. In addition, the distinct nucleolar localization of NS4, being expressed by a virus that replicates exclusively in the cytoplasm, offers new avenues to investigate the multiple roles played by the nucleolus in the biology of the cell