4,533 research outputs found

    Recolha e investigação de metabólitos secundários de organismos marinhos de duas ilhas açoreanas, Faial e São Jorge.

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    In March and April of 1997 a total of 35 samples of marine organisms were collected from the Azorean Islands of Faial and SĂŁo Jorge. These samples included 3 species of Chlorophyta, 7 species of Phaeophyta, 10 species of Rhodophyta, 2 species of Chordata, 3 species of Mollusca, and 7 species of Porifera. Of these samples Laxosuberites rugosus (Porifera), and Pachymatisma johnstonia (Porifera), are new records for the Azores. Secondary metabolite investigations of a number of these samples led to the isolation of para-hydroxybenzyl cyanide from the sponge Laxosuberites rugosus, and oxindol from the sponge Tedania anhelans. Both these compounds are reported here from the marine environment for the first time. These compounds were assessed for their human immunodeficiency virus type 1 reverse transcriptase (HIV-1-RT) and tyrosine kinase (TK) inhibition activities, and para-hydroxybenzyl cyanide found to inhibit the activity of TK to 64% at the 200 Fg/ml level. This is the first report of the TK activity of parahydroxybenzyl cyanide

    Effects of early gestation GH administration on placental and fetal development in sheep.

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    Ovine GH (oGH) is synthesized in placental tissue during maximal placental growth and development. Our objectives were to localize oGH mRNA in the placenta, and study the impact of exogenous GH on twin pregnancies during the normal window (35-55 days of gestational age; dGA) of placental expression. In situ hybridization localized oGH mRNA in uterine luminal epithelium but not in tissues of fetal origin. While maternal GH and IGF-I concentrations were increased (

    An Overview of Technology Investments in the NASA Entry Systems Modeling Project

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    ESM was created with two primary technical areas: Aerosciences and Materials. One of the first project deliverables, in both technology areas, was the development of Key Performance Parameters (KPPs), which are used to gauge the rate of progress in technology maturation, and to inform eventual technology downselects. In addition, the project was tasked to identify stakeholders or customers for proposed technology investments. While pull technologies are permitted within STMD, those capabilities that have strong customer support and a clear infusion plan are given higher priority. The current investment portfolio and achievements will be summarized in this paper

    The Chief HR Officer’s Role in CEO Succession: The View from the Board

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    Interviews with 22 members of public and private company boards revealed their beliefs about and expectations for CHROs in the Chief Executive Officer (CEO) succession process. Board members distinguished between credible CHROs who can add significant value to the process and those CHROs who they do not want to see included in almost any aspect of the process. When credible, board members want CHROs to have confidential conversations with the current CEO, to create processes and development plans for potential successors, and to provide their own independent insights regarding candidate strengths and weaknesses. Directors noted that CHROs who add value must display expertise, honesty, transparency, courage, and the ability to build trusting relationships

    Albatross: Rolling on a Sea of Data

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    Big deals and journal package incentives are an increasing reality for academic libraries, yet the solutions for evaluating these package scenarios in a timely, cost-effective manner are few. The proliferation of these offers requires the examination of numerous and complex questions. There is a need to know the utilization and strength of a package, the inflation costs for various titles and packages, and the ability to identify cost trends. A team of librarians at Virginia Tech created a solution for addressing these concerns and for managing their journal data by designing and developing an in-house database. Albatross, named in reference to The Rime of the Ancient Mariner, is a database created to gather journal usage data and cost data in a central environment where the data can then be queried to use in return-on-investment analysis and journal package assessments

    Structure of the regulatory hyaluronan binding domain in the inflammatory leukocyte homing receptor CD44

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    Adhesive interactions involving CD44, the cell surface receptor for hyaluronan, underlie fundamental processes such as inflammatory leukocyte homing and tumor metastasis. Regulation of such events is critical and appears to be effected by changes in CD44 N-glycosylation that switch the receptor "on" or "off" under appropriate circumstances. How altered glycosylation influences binding of hyaluronan to the lectin-like Link module in CD44 is unclear, although evidence suggests additional flanking sequences peculiar to CD44 may be involved. Here we show using X-ray crystallography and NMR spectroscopy that these sequences form a lobular extension to the Link module, creating an enlarged HA binding domain and a formerly unidentified protein fold. Moreover, the disposition of key N-glycosylation sites reveals how specific sugar chains could alter both the affinity and avidity of CD44 HA binding. Our results provide the necessary structural framework for understanding the diverse functions of CD44 and developing novel therapeutic strategies

    Permanent vs transitory components and economic fundamentals

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    Any non-stationary series can be decomposed into permanent (or “trend”) and transitory (or “cycle”) components. Typically some atheoretic pre-filtering procedure is applied to extract the permanent component. This paper argues that analysis of the fundamental underlying stationary economic processes should instead be central to this process. We present a new derivation of multivariate Beveridge-Nelson permanent and transitory components, whereby the latter can be derived explicitly as a weighting of observable stationary processes. This allows far clearer economic interpretations. Different assumptions on the fundamental stationary processes result in distinctly different results; but this reflects deep economic uncertainty. We illustrate with an example using Garratt et al’s (2003a) small VECM model of the UK economy

    Simultaneous Observations of Comet C/2002 T7 (LINEAR) with the Berkeley-Illinois-Maryland Association and Owens Valley Radio Observatory Interferometers: HCN and CH_3OH

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    We present observations of HCN J = 1-0 and CH_3OH J(K_a, K_c) = 3(1, 3)-4(0, 4) A+ emission from comet C/2002 T7 (LINEAR) obtained simultaneously with the Owens Valley Radio Observatory (OVRO) and Berkeley-Illinois-Maryland Association (BIMA) millimeter interferometers. We combined the data from both arrays to increase the (u, v) sampling and signal to noise of the detected line emission. We also report the detection of CH_3OH J(K_a, K_c) = 8(0, 8)-7(1, 7) A^+ with OVRO data alone. Using a molecular excitation code that includes the effects of collisions with water and electrons, as well as pumping by the Solar infrared photons (for HCN alone), we find a production rate of HCN of 2.9 × 10^(26) s^(–1) and for CH_3OH of 2.2 × 10^(27) s^(–1). Compared to the adopted water production rate of 3 × 10^(29) s^(–1), this corresponds to an HCN/H_2O ratio of 0.1% and a CH_3OH/H_2O ratio of 0.7%. We critically assess the uncertainty of these values due to the noise (~10%), the uncertainties in the adopted comet model (~50%), and the uncertainties in the adopted collisional excitation rates (up to a factor of 2). Pumping by Solar infrared photons is found to be a minor effect for HCN, because our 15" synthesized beam is dominated by the region in the coma where collisions dominate. Since the uncertainties in the derived production rates are at least as large as one-third of the differences found between comets, we conclude that reliable collision rates and an accurate comet model are essential. Because the collisionally dominated region critically depends on the water production rate, using the same approximate method for different comets may introduce biases in the derived production rates. Multiline observations that directly constrain the molecular excitation provide much more reliable production rates

    Precision Measurement of the Proton and Deuteron Spin Structure Functions g2 and Asymmetries A2

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    We have measured the spin structure functions g2p and g2d and the virtual photon asymmetries A2p and A2d over the kinematic range 0.02 < x < 0.8 and 0.7 < Q^2 < 20 GeV^2 by scattering 29.1 and 32.3 GeV longitudinally polarized electrons from transversely polarized NH3 and 6LiD targets. Our measured g2 approximately follows the twist-2 Wandzura-Wilczek calculation. The twist-3 reduced matrix elements d2p and d2n are less than two standard deviations from zero. The data are inconsistent with the Burkhardt-Cottingham sum rule if there is no pathological behavior as x->0. The Efremov-Leader-Teryaev integral is consistent with zero within our measured kinematic range. The absolute value of A2 is significantly smaller than the sqrt[R(1+A1)/2] limit.Comment: 12 pages, 4 figures, 2 table
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