The association of selenium levels with markers of cardiovascular disease

Background: Oxidative stress is a key precursor to atherosclerosis, endothelial dysfunction and arterial stiffness, which are three mechanisms of the progression of cardiovascular disease (CVD). Selenium (Se) is an essential mineral that comprises at least 25 selenoproteins in humans. Many of these selenoproteins play antioxidant roles that are crucial to arterial health and endothelial function. A 2015 meta-analysis of observational studies proposed that CVD risk is significantly decreased only within the narrow selenium range of 55 to 145 µg/L. Methods: Data were previously collected from the Women and Infant Study of Healthy Hearts (WISH). Serum samples from this study were analyzed to determine Se concentrations using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The distribution of Se in this sample was examined as were linear and quadratic associations with carotid intima-media thickness (cIMT), pulse wave velocity (PWV) and flow mediated dilation (FMD). Sub-group analyses were performed to examine these relationships within and outside of the reported beneficial range of Se status. Results: Se concentrations ranged from 58 to 598 µg/L, with a median of 172 µg/L. No participants were deficient in Se, but 74% had selenium levels higher than 145 µg/L. The distribution of Se was skewed left, so Se levels were natural log transformed for the analyses. Quadratic relationships between Se level and cIMT, FMD and PWV had better fit compared to linear relationships. There were no significant associations between Se status and cIMT (p=0.14), PWV (p=0.51) or FMD (p=0.51). There was a significant linear relationship between Se levels greater than 145 µg/L and PWV (p=0.006). Conclusions: On average, the sample had good cardiovascular health and was relatively young to observe subclinical CVD progression. There may be an inverse association between selenium status and pulse wave velocity, a marker of arterial stiffness. This novel finding may lead to a greater understanding of the mechanisms of arterial stiffness, a major risk factor for CVD, which has great public health importance

CORRELATION BETWEEN IMPAIRMENT AND MOTOR PERFORMANCE DURING REACHING TASKS IN SUBJECTS WITH SPASTIC HEMIPARESIS

Objective: The main purposes of this study were to examine, in subjects with chronic hemiparesis following a stroke: (i) the correlations between tests of muscle tone, stiffness, spasticity, paresis and co-contraction, and (ii) the correlations of these tests and measurements of impairment to upper extremity motor performance. Design: Prospective, cross-sectional, correlation matrix using sample of convenience. Subjects: Thirteen subjects with chronic hemiparesis secondary to a cerebrovascular accident (stroke) were tested. Methods: Subjects were assessed using the Fugl-Meyer Upper Extremity Motor Assessment, modified Ashworth scale, deep tendon reflexes, and muscle characteristics that included quantification of muscle stiffness, paresis and co-contraction during a voluntary reaching task and during passive movements. Surface electromyographic and myotonometric muscle stiffness data were obtained during movement trials. Results: Biceps and triceps brachii muscle paresis and excess biceps brachii co-contraction during voluntary reaching had the highest correlations to decreased motor performance. Muscle tone measurements did not have significant correlations to upper extremity performance. Conclusion: Paresis of elbow flexors and extensors and excess co-contraction of the biceps brachii during voluntary reaching appear to be most predictive of upper extremity motor performance. Results are discussed in relation to the specific challenges these findings pose for spastic paresis clinical management

Spectropolarimetry of SN 2011dh in M51: geometric insights on a Type IIb supernova progenitor and explosion

We present seven epochs of spectropolarimetry of the Type IIb supernova (SN) 2011dh in M51, spanning 86 days of its evolution. The first epoch was obtained 9 days after the explosion, when the photosphere was still in the depleted hydrogen layer of the stripped-envelope progenitor. Continuum polarization is securely detected at the level of P~0.5% through day 14 and appears to diminish by day 30, which is different from the prevailing trends suggested by studies of other core-collapse SNe. Time-variable modulations in P and position angle are detected across P-Cygni line features. H-alpha and HeI polarization peak after 30 days and exhibit position angles roughly aligned with the earlier continuum, while OI and CaII appear to be geometrically distinct. We discuss several possibilities to explain the evolution of the continuum and line polarization, including the potential effects of a tidally deformed progenitor star, aspherical radioactive heating by fast-rising plumes of Ni-56 from the core, oblique shock breakout, or scattering by circumstellar material. While these possibilities are plausible and guided by theoretical expectations, they are not unique solutions to the data. The construction of more detailed hydrodynamic and radiative-transfer models that incorporate complex aspherical geometries will be required to further elucidate the nature of the polarized radiation from SN 2011dh and other Type IIb supernovae.Comment: Post-proof edit. Accepted to MNRAS 2015 Aug 1

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals. Pages 49-52, v17n2, provided courtesy of Howard Gotlieb Archival Research Center

PTF11iqb: Cool supergiant mass loss that bridges the gap between Type IIn and normal supernovae

PTF11iqb was initially classified as a TypeIIn event caught very early after explosion. It showed narrow Wolf-Rayet (WR) spectral features on day 2, but the narrow emission weakened quickly and the spectrum morphed to resemble those of Types II-L and II-P. At late times, Halpha emission exhibited a complex, multipeaked profile reminiscent of SN1998S. In terms of spectroscopic evolution, we find that PTF11iqb was a near twin of SN~1998S, although with weaker interaction with circumstellar material (CSM) at early times, and stronger CSM interaction at late times. We interpret the spectral changes as caused by early interaction with asymmetric CSM that is quickly (by day 20) enveloped by the expanding SN ejecta photosphere, but then revealed again after the end of the plateau when the photosphere recedes. The light curve can be matched with a simple model for weak CSM interaction added to the light curve of a normal SN~II-P. This plateau requires that the progenitor had an extended H envelope like a red supergiant, consistent with the slow progenitor wind speed indicated by narrow emission. The cool supergiant progenitor is significant because PTF11iqb showed WR features in its early spectrum --- meaning that the presence of such WR features in an early SN spectrum does not necessarily indicate a WR-like progenitor. [abridged] Overall, PTF11iqb bridges SNe~IIn with weaker pre-SN mass loss seen in SNe II-L and II-P, implying a continuum between these types.Comment: 21 pages, 12 figures, submitted to MNRA

The Berkeley Sample of Stripped-Envelope Supernovae

We present the complete sample of stripped-envelope supernova (SN) spectra observed by the Lick Observatory Supernova Search (LOSS) collaboration over the last three decades: 888 spectra of 302 SNe, 652 published here for the first time, with 384 spectra (of 92 SNe) having photometrically-determined phases. After correcting for redshift and Milky Way dust reddening and reevaluating the spectroscopic classifications for each SN, we construct mean spectra of the three major spectral subtypes (Types IIb, Ib, and Ic) binned by phase. We compare measures of line strengths and widths made from this sample to the results of previous efforts, confirming that O I {\lambda}7774 absorption is stronger and found at higher velocity in Type Ic SNe than in Types Ib or IIb SNe in the first 30 days after peak brightness, though the widths of nebular emission lines are consistent across subtypes. We also highlight newly available observations for a few rare subpopulations of interest.Comment: 13 pages; 14 figures; 3 tables. Accepted for publication in MNRA

SN 2011hw: Helium-Rich Circumstellar Gas and the Luminous Blue Variable to Wolf-Rayet Transition in Supernova Progenitors

We present optical photometry and spectroscopy of the peculiar Type IIn/Ibn supernova SN2011hw. Its light curve exhibits a slower decline rate than normal SNeIbc, with a peak absolute magnitude of -19.5 (unfiltered) and a secondary peak of -18.3 mag (R). Spectra of SN2011hw are unusual compared to normal SN types, most closely resembling the spectra of SNeIbn. We center our analysis on comparing SN 2011hw to the well-studied TypeIbn SN2006jc. While the two SNe have many important similarities, the differences are quite telling: compared to SN2006jc, SN2011hw has weaker HeI and CaII lines and relatively stronger H lines, its light curve has a higher luminosity and slower decline rate, and emission lines associated with the progenitor's CSM are narrower. One can reproduce the unusual continuum shape of SN2011hw with equal contributions of a 6000K blackbody and a spectrum of SN2006jc. We attribute this emission component and many other differences between the two SNe to extra opacity from a small amount of additional H in SN2011hw, analogous to the small H mass that makes SNeIIb differ from SNeIb. Slower speeds in the CSM and elevated H content suggest a connection between the progenitor of SN2011hw and the class of Ofpe/WN9 stars, which have been associated with LBVs in their hot quiescent phases between outbursts, and are H-poor - but not H-free like classical Wolf-Rayet (WR) stars. We conclude that the similarities and differences between SN2011hw and SN2006jc can be largely understood if their progenitors exploded at different points in the transitional evolution from an LBV to a WR star.Comment: 11 pages, 7 figures, submitted to MNRA

Reverberation Mapping of the Kepler-Field AGN KA1858+4850

KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3-m telescope from February to November of 2012, and obtained complementary V-band images from five other ground-based telescopes. We measured the H-beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method, and found rest-frame lags of lag_CCF = 13.53 (+2.03, -2.32) days and lag_JAVELIN = 13.15 (+1.08, -1.00) days. The H-beta root-mean-square line profile has a width of sigma_line = 770 +/- 49 km/s. Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M_BH = 8.06 (+1.59, -1.72) x 10^6 M_sun for the mass of the central black hole and an Eddington ratio of L/L_Edd ~ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei