• Title/Summary/Keyword: Michael Addition

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Hexagonal reciprocating pump: advantages and weaknesses

  • Stanko, Milan;Golan, Michael
    • International Journal of Fluid Machinery and Systems
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    • v.6 no.3
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    • pp.121-136
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    • 2013
  • This paper reports the 1-D fluid transient simulation results of the discharge flow conditions in a 6-cylinder reciprocating slurry pump. Two discharge manifold configurations are studied comparatively; a case with a hexagon shaped discharge manifold where each cylinder discharges at a single vertex, and a case where all the cylinders discharges are lumped together into a tank shaped manifold. In addition, the study examines the effect of two pulsation mitigation measures in the case of hexagonal manifold; a single inline orifice in one of the hexagon sides and a volumetric dampener at the manifold outlet. The study establishes the pressure and flow fluctuation characteristics of each configuration and decouples the pulsation characteristics of the pump and the discharge manifold.

Secondary Structure, 1H, 13C and 15N Resonance Assignments and Molecular Interactions of the Dishevelled DIX Domain

  • Capelluto, Daniel G.S.;Overduin, Michael
    • BMB Reports
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    • v.38 no.2
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    • pp.243-247
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    • 2005
  • Dishevelled (Dvl) is a positive regulator of the canonical Wnt signaling pathway, which regulates the levels of $\beta$-catenin. The $\beta$-catenin oncoprotein depends upon the association of Dvl and Axin proteins through their DIX domains, and its accumulation directs the expression of specific developmental-related genes at the nucleus. Here, the $^1H$, $^{13}C$, and $^{15}N$ resonances of the human Dishevelled 2 DIX domain are assigned using heteronuclear nuclear magnetic resonance (NMR) spectroscopy. In addition, helical and extended elements are identified based on the NMR data. The results establish a structural context for characterizing the actin and phospholipid interactions and binding sites of this novel domain, and provide insights into its role in protein localization to stress fibers and cytoplasmic vesicles during Wnt signaling.

Transverse relaxation-optimized HCN experiment for tautomeric states of histidine sidechains

  • Schmidt, Holger;Himmel, Sebastian;Walter, Korvin F.A.;Klaukien, Volker;Funk, Michael;Lee, Dong-Han
    • Journal of the Korean Magnetic Resonance Society
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    • v.12 no.2
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    • pp.89-95
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    • 2008
  • Function of protein is frequently related with tautomeric states of histidine sidechains. Thus, several NMR experiments were developed to determine the tautomeric states of histidines. However, poor sensitivity of these experiments caused by long duration of magnetization transfer periods is unavoidable. Here, we alleviate the sensitivity of HCN experiment for determining the tautomeric states of histidine residues using TROSY principle to suppress transverse relaxation of $^{13}C$ spins during long polarization transfer delays involving $^{13}C-^{15}N$ scalar couplings. In addition, this experiment was used to assign the sidechain resonances of histidines. These assignments can be used to follow the pH-titration of histidine sidechains.

Genotoxicity Study of AS6, a Triterpenoid Derivatives

  • Kwon, Jung;Lee, Michael;Cha, Kyung-Hoi;Kim, Jong-Choon;Han, Jung-Hee
    • Biomolecules & Therapeutics
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    • v.11 no.3
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    • pp.190-195
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    • 2003
  • To assess the genotoxicity of AS6, several classical toxicological tests were performed. In Ames test, AS6 did not show any transformation of revertant with or without S-9 metabolic activating system, indicating the lack of mutagenic effect of the compound. To assess clastogenic effect, in vivo micronucleus and in vitro chromosomal aberration assays were performed using male ICR mice and Chinese hamster lung (CHL) fibroblast cells, respectively. Chromosomal aberration was not induced regardless of the presence of S-9 metabolic activating system. In addition, AS6 did not cause any increase in the incidence of micronucleated polychromatic erythrocytes at any of the dose levels, suggesting little clastogenicity in vitro or in vivo. Taken together, these results demonstrate that AS-6 has no mutagenic effect in our test system.

Effect of Gelatin on the Stability of Heavy Chain Monoclonal Antibody Production from Plant Suspension Cultures

  • Ryland, J.;Robert, P.;Michael, Linzmaier;Lee, James M.
    • Journal of Microbiology and Biotechnology
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    • v.10 no.4
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    • pp.449-454
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    • 2000
  • The heavy chain monoclonal antibody (HC MAb) was produced in suspension cultures of genetically modified Nicotiana tabacum. The HC MAb secreted to the medium was unstable due to unfavorable interactions in the plant cell medium. The addition of gelatin (5g/l) stabilized the extracellular HC MAb and increased its production 10-fold. A kinetic model was developed describing the interaction between the secretedprotein and the stabilizer. The model accounted for the inactivation of the protein by simple aggregation and general instability. It was assumed that the secreted protein and the stabilizer form a stable complex. Culturing the cells semicontinuously could further increase the productivity of HC MAb.

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Applications of Diffusion Tensor Imaging

  • Moseley, Michael E.
    • Proceedings of the KSMRM Conference
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    • 2001.11a
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    • pp.155-161
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    • 2001
  • Anisotropic DWI - Mapping of the Proton Diffusion "tensor". In neural ordered tissue, it is thought that water diffusion is mainly influenced by the presence of myelin sheaths and intracellular structures. Perpendicular to the fiber tracts, the cholesterol-laden myelin lipid bilayers might restrict or hinder the spins from diffusing through the normally highly permeable cytomembrane. Diffusion along the fiber is more or less determined by subcellular structures, such as the endoplasmatic reticulum, mitochondria, neuro-filaments and macromolecules. In addition to that, the entire complex of axons and stabilizing tissue (i.e., glia cells, astrocytes) is also assumed to influence diffusion due to the tortuosity of proton translation, but the uniform distribution of such cells throughout the brain might render this notion less important as initially anticipated.

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An Efficient Algorithm for Real-Time 3D Terrain Walkthrough

  • Hesse, Michael;Gavrilova, Marina L.
    • International Journal of CAD/CAM
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    • v.3 no.1_2
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    • pp.111-117
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    • 2003
  • The paper presents an efficient algorithm based on ROAM for visualization of large scale terrain models in real-time. The quality and smoothness of the terrain data visualization within a 3D interactive environment is preserved, while the complexity of the algorithm is kept on a reasonable level. The main contribution of the paper is an introduction of a number of efficient techniques such as implicit coordinates method within the patch array representing ROAM and the viewpoint dependent triangle rendering method for dynamic level of detail (LOD) updates. In addition, the paper presents experimental comparison of a variety of culling techniques, including a newly introduced method: relational position culling. These techniques are incorporated in the visualization software, which allows to achieve more realistic terrain representation and the real-time level of detail reduction.

Selective Extraction and Quantification of Glutathione using Maleimide-Presenting Gold Nanoparticles

  • Oh, Hongseok;Lee, Jeongwook;Yeo, Woon-Seok
    • Bulletin of the Korean Chemical Society
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    • v.35 no.10
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    • pp.3047-3051
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    • 2014
  • In this paper, we describe a new method for the selective extraction and quantification of glutathione (GSH) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and maleimide-presenting gold nanoparticles (Mal-AuNPs). Our strategy utilizes the Michael addition to selectively extract GSH, from chosen samples, onto the maleimide of Mal-AuNPs. After the extraction step, the GSH bound to the AuNPs was analyzed by MALDI-TOF MS in the presence of an internal standard which was prepared by reacting Mal-AuNPs with isotope-labeled GSH ($GSH^*$). The $GSH^*$ has the same structure as GSH but a higher molecular weight, and therefore, enables absolute quantification of GSH by comparing the mass signal intensities of the GSH- and $GSH^*$-conjugated alkanethiols. Our strategy was verified by analyzing GSH-spiked fetal bovine serum and NIH 3T3 cells.

Bioactivities and Potential Mechanisms of Action for Conjugated Fatty Acids

  • Park, Yeon-Hwa;Pariza, Michael W.
    • Food Science and Biotechnology
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    • v.18 no.3
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    • pp.586-593
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    • 2009
  • Since conjugated linoleic acid (CLA) was identified as a principal anticancer component from ground beef in the 1980s, CLA research has discovered that CLA has a wide range of biologically beneficial effects. Clinical studies with CLA are on the rise, and it is apparent that CLA may not be as effective in humans as in rodents, in particular its anti-obesity aspect. In addition, research with regard to other conjugated fatty acids as well as CLA metabolites is still in its infancy. Investigation of bioactivities for other conjugated fatty acids and CLA metabolites may help to extend the understanding of CLA and its mechanisms of actions. This may pose an opportunity to use CLA more efficiently and expand the future use of other conjugated fatty acids as pharmacological agents to assist current treatments.

Dyeing Properties of Cationized Cotton Fiber with Acid Dye (캐티온화한 면섬유에 대한 산성염료의 염색성)

  • 정영진;이영희;박수민;겸경환
    • Textile Coloration and Finishing
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    • v.6 no.1
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    • pp.54-61
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    • 1994
  • Acrylamidomethylated cellulose(AMC) was prepared by a reaction of N-methy-lolacrylamide(NMA) in the presence of acid catalyst, and pendent C=C double bonds are created on cellulose. Using the pendant double bonds as a site for Michael addition, a number of modified cellulose could be readily prepared. When AMC is treated in an aqueous solution containing sodium dihydrogen phospate and methylamine, the chemical structure of cellulose is represented as follow ; Cell-O-$CH_{2}$-NHCO-$CH_{2}$-$CH_{2}$-NHMe. Therefore in this paper, dyeing properties of modified cellulose for the acid dye were investigated.

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