1,344 research outputs found

    Determination of radical scavenging activities of some pyrimidine derivatives

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    Purpose: To synthesize some pyrimidine derivatives and investigate their radical scavenging activities. Methods: A series of newly pyranopyrimidines derivatives and dithiopyridopyrimidinediones were synthesized by condensation of barbituric acid, malononitrile and different substituted benzaldehydes reacted with 1,4-Diazabicyclo[2.2.2] octane (DABCO) as a base. Compounds P1-7 (series 1),  S1-11 (series 2) Scheme 1 and 6-amino-2-thiouracil with aromatic aldehydes in glacial acetic acid under reflux J1-13 (series 3) Scheme 2. 1H & 13C NMR, CHN, GC-MS and IR were used to characterize the compounds and were also screened for radical scavenging activity using 2,2-diphenyl- 1-picrylhydrazyl (DPPH) radical scavenging activity (IC50 = 50 μg/ml). Results: The potency of radical scavenging activity was ranked as series 1 > series 3 > series 2. Compounds P3, J4, S10, P5, P7 with inhibitory  concentration at 50 % level (IC50) of 12, 40, 48, 50, and 54 μg/ml, respectively, showed radical scavenging activity equal or more potent than the standard antioxidant, ascorbic acid (IC50 = 50 μg/ml). Conclusion: Series of newly pyranopyrimidines and dithiopyridopyrimidinediones derivatives have been successfully synthesized, and they  demonstrate good radical scavenging activity. Keywords: Pyranopyrimidine, Dipyrimidines, Anti-oxidant, DPPH, Ascorbic acid, Radical scavengin

    Project Passport: An Integrated Group-Centered Approach Targeting Pregnant Teens and Their Partners

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    Objective: To describes the development of Project Passport, a perinatal intervention designed to reduce negative outcomes among pregnant teens. Methods: A logic model guided the planning, development and evaluation plan for the intervention. It included the selection of health goals, behaviors to be targeted, determinants of the selected behaviors, and activities to impact each selected determinant. Results: The process resulted in the formulation of an intervention that incorporates CenteringPregnancy, a group model of prenatal care, Positive Youth Development components, and male involvement. The evaluation examines the effectiveness of the intervention in enhancing health, educational and psychosocial outcomes among pregnant adolescents. Conclusions: The present program was designed to address an important gap in evidence-based interventions targeting pregnant adolescents and their partners

    The extended tails of Palomar 5: A ten degree arc of globular cluster tidal debris

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    Using wide-field photometric data from the Sloan Digital Sky Survey (SDSS) we recently showed that the Galactic globular cluster Palomar 5 is in the process of being tidally disrupted. Its tidal tails were initially detected in a 2.5 degree wide band along the celestial equator. A new analysis of SDSS data for a larger field now reveals that the tails of Pal 5 have a much larger spatial extent and can be traced over an arc of 10 deg across the sky, corresponding to a projected length of 4 kpc at the distance of the cluster. The number of former cluster stars found in the tails adds up to about 1.2 times the number of stars in the cluster. The radial profile of stellar surface density in the tails follows approximately a power law r^gamma with -1.5 < gamma < -1.2. The stream of debris from Pal 5 is significantly curved, which demonstrates its acceleration by the Galactic potential. The cluster is presently near the apocenter but has repeatedly undergone disk crossings in the inner part of the Galaxy leading to strong tidal shocks. Our results suggest that the observed debris originates mostly from mass loss within the last 2 Gyrs. The cluster is likely to be destroyed after the next disk crossing, which will happen in about 100 Myr. (abridged)Comment: 44 pages, including 14 figures (Figs.1,3 & 14 with decreased resolution), accepted for publication in the Astronomical Journa

    Enhancing Emotional Safety in a Graduate School Setting

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    In the United States, racial disparities in education can be seen in rates of graduation from high school through doctoral programs, with People of Color reporting rates that are significantly lower than their White peers. Academic success has been significantly predicted in prior research by the support of teaching staff. Our Safety in the Classroom (SITC) program was developed to close the support gap for several different, often-marginalized groups within graduate school classes at a university in southern California. Students within racial, religious, and sexual orientation groups reported stronger perceptions of prejudice when compared to their peers. The SITC program provided all students an additional tool for resolving questions and concerns about any aspect of a particular course, including behaviors or statements of the instructor, and resulted in greater effect sizes on enhanced feelings of safety in the classroom for students of color. These results were achieved without undermining the students’ belief in their own ability to negotiate over or confront problems in the classroom. Expanded use and evaluation of the SITC program could contribute to the growing literature on academic success and achievement among underrepresented groups, providing one possible tool for helping to close the support gap

    The Density and Temperature of Molecular Clouds in M33

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    We have observed the 12^{12}CO J=2-1, J=3-2, and 13^{13}CO J=2-1 lines in a sample of seven giant molecular clouds in the Local Group spiral galaxy M33. The 12^{12}CO/13^{13}CO J=2-1 line ratio is constant across the entire sample, while the observed 12^{12}CO J=3-2/J=2-1 line ratio has a weak dependence on the star formation environment of the cloud, with large changes in the line ratio seen only for clouds in the immediate vicinity of an extremely luminous HII region. A large velocity gradient analysis indicates that clouds without HII regions have temperatures of 10-20 K, clouds with HII regions have temperatures of 15-100 K, and the cloud in the giant HII region has a temperature of at least 100 K. Interestingly, the giant HII region appears capable of raising the kinetic temperature of the molecular gas only for clouds that are quite nearby (<100< 100 pc). The continuous change of physical conditions across the observed range of star formation environments suggests that the unusual physical conditions in the cloud in the giant HII region are due to post-star formation changes in the molecular gas, rather than intrinsic properties of the gas related to the formation of the giant HII region.Comment: 14 pages, aastex, 4 postscript figures; accepted for publication in ApJ; also available at http://www.physics.mcmaster.ca/Wilson_Preprint

    Weak Lensing with SDSS Commissioning Data: The Galaxy-Mass Correlation Function To 1/h Mpc

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    (abridged) We present measurements of galaxy-galaxy lensing from early commissioning imaging data from the Sloan Digital Sky Survey (SDSS). We measure a mean tangential shear around a stacked sample of foreground galaxies in three bandpasses out to angular radii of 600'', detecting the shear signal at very high statistical significance. The shear profile is well described by a power-law. A variety of rigorous tests demonstrate the reality of the gravitational lensing signal and confirm the uncertainty estimates. We interpret our results by modeling the mass distributions of the foreground galaxies as approximately isothermal spheres characterized by a velocity dispersion and a truncation radius. The velocity dispersion is constrained to be 150-190 km/s at 95% confidence (145-195 km/s including systematic uncertainties), consistent with previous determinations but with smaller error bars. Our detection of shear at large angular radii sets a 95% confidence lower limit s>140′′s>140^{\prime\prime}, corresponding to a physical radius of 260h−1260h^{-1} kpc, implying that galaxy halos extend to very large radii. However, it is likely that this is being biased high by diffuse matter in the halos of groups and clusters. We also present a preliminary determination of the galaxy-mass correlation function finding a correlation length similar to the galaxy autocorrelation function and consistency with a low matter density universe with modest bias. The full SDSS will cover an area 44 times larger and provide spectroscopic redshifts for the foreground galaxies, making it possible to greatly improve the precision of these constraints, measure additional parameters such as halo shape, and measure the properties of dark matter halos separately for many different classes of galaxies.Comment: 28 pages, 11 figures, submitted to A

    A New Giant Stellar Structure in the Outer Halo of M31

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    The Sloan Digital Sky Survey has revealed an overdensity of luminous red giant stars ~ 3 degrees (40 projected kpc) to the northeast of M31, which we have called Andromeda NE. The line-of-sight distance to Andromeda NE is within approximately 50 kpc of M31; Andromeda NE is not a physically unrelated projection. Andromeda NE has a g-band absolute magnitude of ~ -11.6 and central surface brightness of ~ 29 mag/sq.arcsec, making it nearly two orders of magnitude more diffuse than any known Local Group dwarf galaxy at that luminosity. Based on its distance and morphology, Andromeda NE is likely undergoing tidal disruption. Andromeda NE's red giant branch color is unlike that of M31's present-day outer disk or the stellar stream reported by Ibata et al. (2001), arguing against a direct link between Andromeda NE and these structures. However, Andromeda NE has a red giant branch color similar to that of the G1 clump; it is possible that these structures are both material torn off of M31's disk in the distant past, or that these are both part of one ancient stellar stream.Comment: 11 pages, 3 figures; ApJ Letters accepted versio
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