920 research outputs found

    Effects of single mutations on the stability of horseradish peroxidase to hydrogen peroxide

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    Horseradish peroxidase (HRP) is a commonly used enzyme in many biotechnological fields. Improvement of HRP stability would further increase its potential application range. In the present study, 13 single- and three double-mutants of solvent exposed, proximal lysine and glutamic acid residues were analysed for enhanced H2O2 stability. Additionally, five single- and one pentuple-consensus mutants were investigated. Most mutants displayed little or no alteration in H2O2 stability; however, three (K232N, K241F and T110V) exhibited significantly increased H2O2 tolerances of 25- (T110V), 18- (K232N), and 12-fold (K241F). This improved stability may be due to an altered enzyme-H2O2 catalysis pathway or to removal of potentially oxidisable residues

    Stronger Constraints on the Evolution of the MBHσM_{\rm{BH}}-\sigma_* Relation up to z0.6z\sim0.6

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    We revisit the possibility of redshift evolution in the MBHσM_{\rm{BH}}-\sigma_* relation with a sample of 22 Seyfert 1 galaxies with black holes (BHs) in the mass range 106.3108.3 M10^{6.3}-10^{8.3}~M_\odot and redshift range 0.03<z<0.570.03<z<0.57 with spectra obtained from spatially resolved Keck/Low-Resolution Imaging Spectrometer observations. Stellar velocity dispersions were measured directly from the Mg Ib region, taking into consideration the effect of Fe II contamination, active galactic nucleus (AGN) dilution, and host-galaxy morphology on our measurements. BH masses are estimated using the Hβ\beta line width, and the luminosity at 5100 \overset{\lower.5em\circ}{\mathrm{A}} is estimated from surface brightness decomposition of the AGN from the host galaxy using high-resolution imaging from the Hubble Space Telescope. Additionally, we investigate the use of the [O III]λ5007\lambda5007 emission line width as a surrogate for stellar velocity dispersion, finding better correlation once corrected for Fe II contamination and any possible blueshifted wing components. Our selection criteria allowed us to probe lower-luminosity AGNs and lower-mass BHs in the non-local universe than those measured in previous single-epoch studies. We find that any offset in the MBHσM_{\rm{BH}}-\sigma_* relation up to z0.6z\sim0.6 is consistent with the scatter of local BH masses, and address the sources of biases and uncertainties that contribute to this scatter.Comment: Accepted 14 May 2019 for publication in ApJ. 42 pages, 12 figures, 4 tables. Corrected for typographical error

    DETERMINANTS OF COW-CALF PAIR PRICES

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    Cow-calf prices are determined by interaction of many factors. At a particular auction, cow-calf pair prices often had a range of 75% of the mean price. This variability suggests that producers need to be informed regarding cow-calf price determinants. This study uses auction data during 1993 to estimate price differentials associated with cow-calf pair characteristics using a hedonic model. Cow breed, age, health, conditions, horns, frame, and whether the cow had been bred back were significant price determinants. Calf weight, health, and frame had significant price impacts. Highest prices were paid for pens containing 9-12 pairs of young Angus, dehorned, bred back, healthy cows with heavy healthy calves.Demand and Price Analysis,

    ImageJ2: ImageJ for the next generation of scientific image data

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    ImageJ is an image analysis program extensively used in the biological sciences and beyond. Due to its ease of use, recordable macro language, and extensible plug-in architecture, ImageJ enjoys contributions from non-programmers, amateur programmers, and professional developers alike. Enabling such a diversity of contributors has resulted in a large community that spans the biological and physical sciences. However, a rapidly growing user base, diverging plugin suites, and technical limitations have revealed a clear need for a concerted software engineering effort to support emerging imaging paradigms, to ensure the software's ability to handle the requirements of modern science. Due to these new and emerging challenges in scientific imaging, ImageJ is at a critical development crossroads. We present ImageJ2, a total redesign of ImageJ offering a host of new functionality. It separates concerns, fully decoupling the data model from the user interface. It emphasizes integration with external applications to maximize interoperability. Its robust new plugin framework allows everything from image formats, to scripting languages, to visualization to be extended by the community. The redesigned data model supports arbitrarily large, N-dimensional datasets, which are increasingly common in modern image acquisition. Despite the scope of these changes, backwards compatibility is maintained such that this new functionality can be seamlessly integrated with the classic ImageJ interface, allowing users and developers to migrate to these new methods at their own pace. ImageJ2 provides a framework engineered for flexibility, intended to support these requirements as well as accommodate future needs

    An Infrared Comparison of Type-1 and Type-2 Quasars

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    We model the optical to far-infrared SEDs of a sample of six type-1 and six type-2 quasars selected in the mid-infrared. The objects in our sample are matched in mid-IR luminosity and selected based on their Spitzer IRAC colors. We obtained new targeted Spitzer IRS and MIPS observations and used archival photometry to examine the optical to far-IR SEDs. We investigate whether the observed differences between samples are consistent with orientation-based unification schemes. The type-1 objects show significant emission at 3 micron. They do not show strong PAH emission and have less far-IR emission on average when compared to the type-2 objects. The SEDs of the type-2 objects show a wide assortment of silicate features, ranging from weak emission to deep silicate absorption. Some also show strong PAH features. In comparison, silicate is only seen in emission in the type-1 objects. This is consistent with some of the type-2s being reddened by a foreground screen of cooler dust, perhaps in the host galaxy itself. We investigate the AGN contribution to the far-IR emission and find it to be significant. We also estimate the star formation rate for each of the objects by integrating the modeled far-IR flux and compare this with the SFR found from PAH emission. We find the type-2 quasars have a higher average SFR than the type-1 quasars based on both methods, though this could be due to differences in bolometric luminosities of the objects. While we find pronounced differences between the two types of objects, none of them are inconsistent with orientation-based unification schemes.Comment: Accepted for publication in Ap

    A Distance-Limited Imaging Survey of Sub-Stellar Companions to Solar Neighborhood Stars

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    We report techniques and results of a Palomar 200-inch (5 m) adaptive optics imaging survey of sub-stellar companions to solar-type stars. The survey consists of Ks coronagraphic observations of 21 FGK dwarfs out to 20 pc (median distance about 17 pc). At 1-arcsec separation (17 projected AU) from a typical target system, the survey achieves median sensitivities 7 mag fainter than the parent star. In terms of companion mass, that corresponds to sensitivities of 50MJ (1 Gyr), 70MJ (solar age), and 75MJ (10 Gyr), using the evolutionary models of Baraffe and colleagues. Using common proper motion to distinguish companions from field stars, we find that no system shows positive evidence of a previously unknown substellar companion (searchable separation about 20-250 projected AU at the median target distance).Comment: 29 pages, 5 figures. Carson et al. 2008, AJ, in pres

    Improving self-management in a complex population through patient-centered education and interdisciplinary communication

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    The residual cognitive and physical deficits of traumatic brain injury and stroke create unique challenges during rehabilitation. A microsystem assessment of an inpatient rehabilitation unit serving traumatic brain injury and stroke patients identified areas for improvement in patient satisfaction and timely discharge preparation. Both of these issues were linked to poor communication and late initiation of education of patients and care partners. A literature review revealed that formal education and discharge programs for these populations have little effect on patient and care partner outcomes. As a result, an evidence-based project was undertaken using patient-centered education practices shown to be effective in improving patient and care partner satisfaction and self-management in patients returning to the community with residual deficits. A process improvement plan using the Plan-Do-Study-Act model was designed. A process change in patient and care partner education incorporating patient-centered themes and improved interdisciplinary communication was initiated and the results analyzed
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