376 research outputs found

    Detection of C3_{3} in Diffuse Interstellar Clouds

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    The smallest polyatomic carbon chain, C3_{3}, has been identified in interstellar clouds (Av∼_{v}\sim1 mag) towards ζ\zeta Ophiuchi, 20 Aquilae, and ζ\zeta Persei by detection of the origin band in its A1Πu−X1Σg+A^{1}\Pi_{u}-X^{1}\Sigma^{+}_{g} electronic transition, near 4052\AA. Individual rotational lines were resolved up to JJ=30 enabling the rotational level column densities and temperature distributions to be determined. The inferred limits for the total column densities (∼\sim1 to 2×1012\times10^{12} cm−2^{-2}) offer a strong incentive to laboratory and astrophysical searches for the longer carbon chains. Concurrent searches for C2+_2^{+}, C2−_2^{-} and C3−_3^{-} were negative but provide sensitive estimates for their maximum column densities.Comment: 14 pages, 5 figures, 3 tables. To appear in the Astrophysical Journa

    Top-down social modulation of interpersonal observation-execution.

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    Cyclical upper limb movement can involuntarily deviate from its primary movement axis when the performer concurrently observes incongruent biological motion (i.e. interpersonal observation-execution). The current study examined the social modulation of such involuntary motor interference using a protocol that reflected everyday social interactions encountered in a naturalistic social setting. Eighteen participants executed cyclical horizontal arm movements during the observation of horizontal (congruent) or curvilinear (incongruent) biological motion. Both prior to, and during the interpersonal observation-execution task, participants also received a series of social words designed to prime a pro-social or anti-social attitude. The results showed greater orthogonal movement deviation, and thus interference, for the curvilinear compared to horizontal stimuli. Importantly, and opposite to most of the previous findings from work on automatic imitation and mimicry, there was a greater interference effect for the anti-social compared to pro-social prime condition. These findings demonstrate the importance of interpreting the context of social primes, and strongly support predictions of a comparison between the prime construct and the self-concept/-schema and the top-down response modulation of social incentives

    Kinetic Analysis of Substrate Utilization by Native and TNAP-, NPP1-, or PHOSPHO1-Deficient Matrix Vesicles

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    During the process of endochondral bone formation, chondrocytes and osteoblasts mineralize their extracellular matrix by promoting the formation of hydroxyapatite seed crystals in the sheltered interior of membrane-limited matrix vesicles (MVs). Here, we have studied phosphosubstrate catalysis by osteoblast-derived MVs at physiologic pH, analyzing the hydrolysis of ATP, ADP, and PPi by isolated wild-type (WT) as well as TNAP-, NPP1- and PHOSPHO1-deficient MVs. Comparison of the catalytic efficiencies identified ATP as the main substrate hydrolyzed by WT MVs. The lack of TNAP had the most pronounced effect on the hydrolysis of all physiologic substrates. The lack of PHOSPHO1 affected ATP hydrolysis via a secondary reduction in the levels of TNAP in PHOSPHO1-deficient MVs. The lack of NPP1 did not significantly affect the kinetic parameters of hydrolysis when compared with WT MVs for any of the substrates. We conclude that TNAP is the enzyme that hydrolyzes both ATP and PPi in the MV compartment. NPP1 does not have a major role in PPi generation from ATP at the level of MVs, in contrast to its accepted role on the surface of the osteoblasts and chondrocytes, but rather acts as a phosphatase in the absence of TNAP. © 2010 American Society for Bone and Mineral Research

    The clinicopathological and prognostic impact of 14-3-3 sigma expression on vulvar squamous cell carcinomas

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    <p>Abstract</p> <p>Background</p> <p>14-3-3 sigma (σ) promotes G2/M cell cycle arrest by sequestering cyclin B1-CDC2 complex in cytoplasm. Down-regulation of 14-3-3σ, which has been demonstrated in various carcinomas, may contribute to malignant transformation. However, the exact role of 14-3-3σ in the pathogenesis of vulvar carcinoma is not fully characterized, and the prognostic impact of 14-3-3σ protein expression is still unknown.</p> <p>Methods</p> <p>We investigated the 14-3-3σ expression in a series of 302 vulvar squamous cell carcinomas using immunohistochemistry and its associations with clinicopathological factors and clinical outcome.</p> <p>Results</p> <p>In cytoplasm, nucleus and cytoplasm/nucleus of vulvar carcinomas high 14-3-3σ protein expression was found in 72%, 59% and 75% of the carcinomas, respectively, and low levels in 28%, 41% and 25% of the cases, respectively. High level of 14-3-3σ in cytoplasm, nucleus and cytoplasm/nucleus was significantly correlated to large tumor diameter (<it>p </it>= 0.001, <it>p </it>= 0.002 and <it>p </it>= 0.001, respectively) and deep invasion (<it>p </it>= 0.01, <it>p </it>= 0.001 and <it>p </it>= 0.007, respectively). Variations of 14-3-3σ protein expression were not associated to disease-specific survival.</p> <p>Conclusion</p> <p>Our results indicate that 14-3-3σ may be involved in the development of a subset of vulvar squamous cell carcinomas by down-regulation of 14-3-3σ protein. Neither cytoplasmic nor nuclear level of 14-3-3σ expression was associated with prognosis.</p

    Cross-Talk between the Cellular Redox State and the Circadian System in Neurospora

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    The circadian system is composed of a number of feedback loops, and multiple feedback loops in the form of oscillators help to maintain stable rhythms. The filamentous fungus Neurospora crassa exhibits a circadian rhythm during asexual spore formation (conidiation banding) and has a major feedback loop that includes the FREQUENCY (FRQ)/WHITE COLLAR (WC) -1 and -2 oscillator (FWO). A mutation in superoxide dismutase (sod)-1, an antioxidant gene, causes a robust and stable circadian rhythm compared with that of wild-type (Wt). However, the mechanisms underlying the functions of reactive oxygen species (ROS) remain unknown. Here, we show that cellular ROS concentrations change in a circadian manner (ROS oscillation), and the amplitudes of ROS oscillation increase with each cycle and then become steady (ROS homeostasis). The ROS oscillation and homeostasis are produced by the ROS-destroying catalases (CATs) and ROS-generating NADPH oxidase (NOX). cat-1 is also induced by illumination, and it reduces ROS levels. Although ROS oscillation persists in the absence of frq, wc-1 or wc-2, its homeostasis is altered. Furthermore, genetic and biochemical evidence reveals that ROS concentration regulates the transcriptional function of WCC and a higher ROS concentration enhances conidiation banding. These findings suggest that the circadian system engages in cross-talk with the cellular redox state via ROS-regulatory factors

    Sex differences in short-term mate preferences and behavioral mimicry: A semi-naturalistic experiment

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    Item does not contain fulltextStudies on short-term mating (STM) yield sex differences regarding preferences for attractiveness (important towomen, very important to men) and social status (very important to women, not to men) in potential mates. Additionally, men generally report a greater desire to engage in STM than women. So far, this evidence is primarily based on studies using vignettes or surveys. The current study extended the findings on sex differences in STM by examining actual behavior and STM-desires towards real people of the opposite sex. It investigated whether (1) sex differences exist in STM-desire, (2) whether this desire was affected by a confederate's attractiveness and status, and (3) if these sex differences were also reflected in interpersonal behavior (mimicry). In a pub-like laboratory, single heterosexual participants performed a task alongside a confederate of the opposite sex, who differed in attractiveness and social status. Mimicry was observed and explicit STM-desire was assessed. Results showed that men only desired STM more than women in the case of an attractive partner. Women's STMdesire did not vary as a function of status or ttractiveness of the potential partner. Men’s, but not women's, mimicry paralleled these differential STM-desires. These results underline the conditionality of sex differences in STM-desire and provide a useful paradigm to further investigate STM.10 p

    An Aqueous Extract of Fagonia cretica Induces DNA Damage, Cell Cycle Arrest and Apoptosis in Breast Cancer Cells via FOXO3a and p53 Expression

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    Background - Plants have proved to be an important source of anti-cancer drugs. Here we have investigated the cytotoxic action of an aqueous extract of Fagonia cretica, used widely as a herbal tea-based treatment for breast cancer. Methodology/Principal Findings - Using flow cytometric analysis of cells labeled with cyclin A, annexin V and propidium iodide, we describe a time and dose-dependent arrest of the cell cycle in G0/G1 phase of the cell cycle and apoptosis following extract treatment in MCF-7 (WT-p53) and MDA-MB-231 (mutant-p53) human breast cancer cell lines with a markedly reduced effect on primary human mammary epithelial cells. Analysis of p53 protein expression and of its downstream transcription targets, p21 and BAX, revealed a p53 associated growth arrest within 5 hours of extract treatment and apoptosis within 24 hours. DNA double strand breaks measured as ?-H2AX were detected early in both MCF-7 and MDA-MB-231 cells. However, loss of cell viability was only partly due to a p53-driven response; as MDA-MB-231 and p53-knockdown MCF-7 cells both underwent cell cycle arrest and death following extract treatment. p53-independent growth arrest and cytotoxicity following DNA damage has been previously ascribed to FOXO3a expression. Here, in MCF-7 and MDA-MB-231 cells, FOXO3a expression was increased significantly within 3 hours of extract treatment and FOXO3 siRNA reduced the extract-induced loss of cell viability in both cell lines. Conclusions/Significance - Our results demonstrate for the first time that an aqueous extract of Fagonia cretica can induce cell cycle arrest and apoptosis via p53-dependent and independent mechanisms, with activation of the DNA damage response. We also show that FOXO3a is required for activity in the absence of p53. Our findings indicate that Fagonia cretica aqueous extract contains potential anti-cancer agents acting either singly or in combination against breast cancer cell proliferation via DNA damage-induced FOXO3a and p53 expression

    The Effect of the Earned Income Tax Credit in the District of Columbia on Poverty and Income Dynamics

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    Using unique longitudinal administrative tax panel data for the District of Columbia (DC), we assess the combined effect of the DC supplemental earned income tax credit (EITC) and the federal EITC on poverty and income dynamics within Washington, DC, from 2001 to 2011. The EITC in DC merits investigation, as the DC supplement to the federal credit is the largest in the nation. The supplemental DC EITC was enacted in 2000, and has been expanded from 10 percent of the federal credit in 2001 to 40 percent as of 2009. To implement the study, we estimate least squares models with 0/1 dependent variables to estimate the likelihood of net-EITC income above poverty and near-poverty thresholds. We also estimate the likelihood of earnings growth and income stabilization from the EITC. To identify the effect of the EITC, we exploit variation in the EITC subsidy rate from 2008 to 2009, when an additional EITC bracket of 45 percent was added for workers with three or more dependent children, up from 40 percent in the previous year for workers with two or more children. We also estimate a model examining the impact of city-level changes to the EITC. The structure and richness of our data enable us to control for tax filer fixed effects, an important innovation from many previous EITC studies. Overall, we find that the combined EITC raises the likelihood of net-EITC income above poverty and near poverty by as much as 9 percent, with the largest consistent effects accruing to single-parent families
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