298 research outputs found

    Lignocellulosic Micro- And Nanomaterials As Copper Frames For The Evaluation Of The Copper(I)-Catalyzed Azide-Alkyne Cycloaddition

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    Copper was immobilized onto carboxymethyl cellulose, nanofibrillated cellulose, TEMPO-nanofibrillated cellulose, and lignin. The lignocellulosic frames were used with the aim of providing an effective support for catalyst copper and allowing its further reutilization. Each organic support was successful and effective in the coupling of copper with the exception of lignin. These complexes were used as heterogeneous catalysts to produce 1-benzyl-4-phenyl-1H-1,2,3-triazole from the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) between benzyl azide and phenylacetylene. Each reaction was carried out in water and acetonitrile. Those performed in water were completed in 15 minutes while those done in acetonitrile were allowed to react overnight, reaching completion in less than 20 hours. The yields for Cu-CMC resulted in over 90% for those reactions performed in acetonitrile. All catalysts were easy to recover except Cu-lignin which could not be filtered or extracted from the reaction effluent

    Preventing Chlorogenic Acid Quinone-Induced Greening in Sunflower Cookies by Chlorogenic Acid Esterase and Thiol-based Dough Conditioners

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    Sunflower seeds contain a high concentration of chlorogenic acid (CGA), which reacts with amino acids to form green pigments under alkaline conditions during food processing. Here, we present two approaches to prevent green pigment formation in sunflower cookies by (A) Addition of free thiols from cysteine and glutathione to sunflower cookie dough and (B) hydrolyzing CGA into caffeic acid and quinic acid with a CGA esterase from Lactobacillus helveticus. Greening occurred more slowly with cysteine; however, neither cysteine nor glutathione prevented greening in the cookies during storage. Chlorogenic acid esterase hydrolyzed CGA in both sunflower butter and flour, resulting in the complete elimination of greening in the sunflower cookies. CGA esterase treatment was efficient as the enzyme could be applied in low amounts (\u3c100 ppm) directly to the dough without needing to pretreat either sunflower butter or flour. Overall, our data indicate that CGA esterase treatment was an effective method of eliminating unwanted greening in sunflower cookies made with baking soda. Long term, these results may represent a method of increasing the use of sunflower butter and flour in high pH baking applications by enabling their use in neutrally colored baked products such as cookies and muffins

    Analysis of inhibitor of apoptosis protein family expression during mammary gland development

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    <p>Abstract</p> <p>Background</p> <p>Inhibitors-of-Apoptosis-Proteins (IAPs) are an evolutionarily conserved family of proteins capable of regulating several facets of apoptosis. IAPs are frequently dysregulated in cancer, but their role in the regulation of apoptosis during developmental processes is not fully understood. Here we examined the expression of IAPs during the post-natal development of the mouse mammary gland, which is a tissue that exhibits a profound induction of apoptosis during involution.</p> <p>Results</p> <p>Six out of eight mammalian IAP family members are expressed in the mammary gland. Notably, quantitative PCR and immunoblotting revealed that XIAP, c-IAP1 and c-IAP2 are down-regulated in pregnancy and lactation, and prior to the onset of involution. In cultured mammary epithelial cells (MECs), XIAP levels decreased in response to inhibition of growth factor signalling. Maintaining XIAP levels in MECs by expressing exogenous XIAP protected them from all apoptotic stimuli tested.</p> <p>Conclusions</p> <p>These data suggest that the developmental regulation of IAP expression <it>in vivo </it>contributes to naturally occurring programmes of cell death.</p

    Neutrino, Neutron, and Cosmic Ray Production in the External Shock Model of Gamma Ray Bursts

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    The hypothesis that ultra-high energy (>~ 10^19 eV) cosmic rays (UHECRs) are accelerated by gamma-ray burst (GRB) blast waves is assumed to be correct. Implications of this assumption are then derived for the external shock model of gamma-ray bursts. The evolving synchrotron radiation spectrum in GRB blast waves provides target photons for the photomeson production of neutrinos and neutrons. Decay characteristics and radiative efficiencies of the neutral particles that escape from the blast wave are calculated. The diffuse high-energy GRB neutrino background and the distribution of high-energy GRB neutrino events are calculated for specific parameter sets, and a scaling relation for the photomeson production efficiency in surroundings with different densities is derived. GRBs provide an intense flux of high-energy neutrons, with neutron-production efficiencies exceeding ~ 1% of the total energy release. The radiative characteristics of the neutron beta-decay electrons from the GRB "neutron bomb" are solved in a special case. Galaxies with GRB activity should be surrounded by radiation halos of ~ 100 kpc extent from the outflowing neutrons, consisting of a nonthermal optical/X-ray synchrotron component and a high-energy gamma-ray component from Compton-scattered microwave background radiation. The luminosity of sources of GRBs and relativistic outflows in L* galaxies such as the Milky Way is at the level of ~10^40+-1 ergs/s. This is sufficient to account for UHECR generation by GRBs. We briefly speculate on the possibility that hadronic cosmic rays originate from the subset of supernovae that collapse to form relativistic outflows and GRBs. (abridged)Comment: 53 pages, 8 figures, ApJ, in press, 574, July 20, 2002. Substantial revision, previous Appendix expanded to ApJ, 556, 479; cosmic ray origin speculations to Heidelberg (astro-ph/001054) and Hamburg ICRC (astro-ph/0202254) proceeding

    Factors predicting treatment of World Trade Center-related lung injury : a longitudinal cohort study

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    The factors that predict treatment of lung injury in occupational cohorts are poorly defined. We aimed to identify patient characteristics associated with initiation of treatment with inhaled corticosteroid/long-acting beta-agonist (ICS/LABA) >2 years among World Trade Center (WTC)-exposed firefighters. The study population included 8530 WTC-exposed firefighters. Multivariable logistic regression assessed the association of patient characteristics with ICS/LABA treatment for >2 years over two-year intervals from 11 September 2001-10 September 2017. Cox proportional hazards models measured the association of high probability of ICS/LABA initiation with actual ICS/LABA initiation in subsequent intervals. Between 11 September 2001-1 July 2018, 1629/8530 (19.1%) firefighters initiated ICS/LABA treatment for >2 years. Forced Expiratory Volume in 1 s (FEV1), wheeze, and dyspnea were consistently and independently associated with ICS/LABA treatment. High-intensity WTC exposure was associated with ICS/LABA between 11 September 2001-10 September 2003. The 10th percentile of risk for ICS/LABA between 11 September 2005-10 Septmeber 2007 was associated with a 3.32-fold increased hazard of actual ICS/LABA initiation in the subsequent 4 years. In firefighters with WTC exposure, FEV1, wheeze, and dyspnea were independently associated with prolonged ICS/LABA treatment. A high risk for treatment was identifiable from routine monitoring exam results years before treatment initiation

    Discovery and characterization of small molecules that target the Ral GTPase

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    The Ras-like GTPases RalA and B are important drivers of tumor growth and metastasis. Chemicals that block Ral function would be valuable as research tools and for cancer therapeutics. Here, we used protein structure analysis and virtual screening to identify drug-like molecules that bind a site on the GDP-form of Ral. Compounds RBC6, RBC8 and RBC10 inhibited Ral binding to its effector RalBP1, Ral-mediated cell spreading in murine fibroblasts and anchorage-independent growth of human cancer cell lines. Binding of RBC8 derivative BQU57 to RalB was confirmed by isothermal titration calorimetry, surface plasma resonance and 15N-HSQC NMR. RBC8 and BQU57 show selectivity for Ral relative to Ras or Rho and inhibit xenograft tumor growth similar to depletion of Ral by siRNA. Our results show the utility of structure-based discovery for development of therapeutics for Ral-dependent cancers

    Financing Direct Democracy: Revisiting the Research on Campaign Spending and Citizen Initiatives

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    The conventional view in the direct democracy literature is that spending against a measure is more effective than spending in favor of a measure, but the empirical results underlying this conclusion have been questioned by recent research. We argue that the conventional finding is driven by the endogenous nature of campaign spending: initiative proponents spend more when their ballot measure is likely to fail. We address this endogeneity by using an instrumental variables approach to analyze a comprehensive dataset of ballot propositions in California from 1976 to 2004. We find that both support and opposition spending on citizen initiatives have strong, statistically significant, and countervailing effects. We confirm this finding by looking at time series data from early polling on a subset of these measures. Both analyses show that spending in favor of citizen initiatives substantially increases their chances of passage, just as opposition spending decreases this likelihood
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