On the Molecular and Submolecular Structure of the Semiquinone Cations of Alloxazines and Isoalloxazines as Revealed by Electron-Paramagnetic-Resonance Spectroscopy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66144/1/j.1432-1033.1981.tb05295.x.pd

Quantitative numerical analysis of g strain in the EPR of distributed systems and its importance for multicenter metalloproteins

A method for simulation of inhomogeneously broadened EPR of metallo-proteins based on recent theoretical advances is surveyed critically in terms of efficiency and accuracy. From the quality of the experimental spectrum, minimal boundary conditions are established for the spatial integration over the g-strained polycrystal. Computational efficiency is achieved by generating the spectrum as an absorption in g space, reducing the number of molecular orientations computed by filtering mosaic artifacts from the Fourier-transformed spectrum, and generating the lineshape due to g strain from a tabulated distribution function. These techniques provide a reduction in computation time by some two orders of magnitude and make the data analysis of EPR of metalloproteins by minimization practical. The resulting simulation program is superior to current approaches in that it does not introduce artifactual multiplicities, and it is expected to require a smaller number of fitting parameters for the quantitative analysis of most cases. To illustrate its potential, the method is applied to EPR data from the iron-sulfur centers in NADH:Q oxidoreductase and in QH2:ferricytochrome c oxidoreductase, clarifying existing controversies on the stoichiometries of these centers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25873/1/0000436.pd

Optical Spectroscopy of Supernova 1993J During Its First 2500 Days

We present 42 low-resolution spectra of Supernova (SN) 1993J, our complete collection from the Lick and Keck Observatories, from day 3 after explosion to day 2454, as well as one Keck high-dispersion spectrum from day 383. SN 1993J began as an apparent SN II, albeit an unusual one. After a few weeks, a dramatic transition took place, as prominent helium lines emerged in the spectrum. SN 1993J had metamorphosed from a SN II to a SN IIb. Nebular spectra of SN 1993J closely resemble those of SNe Ib and Ic, but with a persistent H_alpha line. At very late times, the H_alpha emission line dominated the spectrum, but with an unusual, box-like profile. This is interpreted as an indication of circumstellar interaction.Comment: 19 pages plus 13 figures, AASTeX V5.0. One external table in AASTeX V4.0, in landscape format. Accepted for publication in A

Photometry and Spectroscopy of GRB 030329 and Its Associated Supernova 2003dh: The First Two Months

We present extensive optical and infrared photometry of the afterglow of gamma-ray burst (GRB) 030329 and its associated supernova (SN) 2003dh over the first two months after detection (2003 March 30-May 29 UT). Optical spectroscopy from a variety of telescopes is shown and, when combined with the photometry, allows an unambiguous separation between the afterglow and supernova contributions. The optical afterglow of the GRB is initially a power-law continuum but shows significant color variations during the first week that are unrelated to the presence of a supernova. The early afterglow light curve also shows deviations from the typical power-law decay. A supernova spectrum is first detectable ~7 days after the burst and dominates the light after ~11 days. The spectral evolution and the light curve are shown to closely resemble those of SN 1998bw, a peculiar Type Ic SN associated with GRB 980425, and the time of the supernova explosion is close to the observed time of the GRB. It is now clear that at least some GRBs arise from core-collapse SNe.Comment: 57 pages, 13 figures, accepted by ApJ, revised per referee's comments, includes full photometry table. Data available at ftp://cfa-ftp.harvard.edu/pub/kstanek/GRB030329 or through WWW at http://cfa-www.harvard.edu/cfa/oir/Research/GRB

Identification of competing ultrafast all-optical switching mechanisms in Si woodpile photonic crystals

We present a systematic study of ultrafast all-optical switching of Si photonic band gap woodpile crystals using broadband tunable nondegenerate pump-probe spectroscopy. At pump-probe coincidence, we investigate the behavior the differential reflectivity at the blue edge of the stopband for a wide range of pump- and probe frequencies. Both dispersive and absorptive features are observed from the probe spectra at coincidence. As the pump frequency is tuned through half the electronic bandgap of Si, the magnitude of both these features increases. For the first time we unambiguously identify this dispersive effect with the electronic Kerr effect in photonic crystals, and attribute the the absorptive features to nondegenerate two photon absorption. The dispersive and absorptive nonlinear coefficients are extracted, and are found to agree well with literature. Finally, we propose a nondegenerate figure of merit (NFOM), which defines the quality of switching for all nondegenerate optical switching processes.Comment: Accepted by JOSA

Bullet-induced synovitis as a cause of secondary osteoarthritis of the hip joint: A case report and review of literature

<p>Abstract</p> <p>Background</p> <p>With increasing prevalence of gunshot injuries we are seeing more patients with retained bullet fragments lodged in their bodies. Embedded lead bullets are usually considered inert after their kinetic energy has dissipated hence these are not removed routinely. However, exposure of any foreign body to synovial fluid may lead to rapid degradation and hence result in systemic absorption, causing local and systemic symptoms. We present the case of a thirty year old man who came to our out patient department with a history of progressive, severe hip pain ten years after a gun shot injury to his right hip.</p> <p>Conclusion</p> <p>The common belief that intraarticular bullets should not be removed has no benefit and may result in unwanted long term complications.</p

The american pediatric society and society for pediatric research joint statement against racism and social injustice

Although the coronavirus disease 2019 pandemic has served as a flashlight, illuminating and unmasking deep socio-economic and health care divides in our country, the terrible events surrounding the horrific murder of Mr. George Floyd in Minneapolis has spawned even greater outrage. As we all know, Mr. Floyd’s death is not an isolated incident, as there have been a tragic string of such deaths in recent years that further reflect deep issues regarding racism and systemic underlying causes of injustice. Unfortunately, the country’s inability to fully address these systemic foundations of injustice persists