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Relevant bibliographies by topics / Monovalent complexes

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Academic literature on the topic 'Monovalent complexes'

Author: Grafiati

Published: 5 June 2025

Last updated: 24 June 2025

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Journal articles on the topic "Monovalent complexes"

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Yehuda, Nofar, Levi A. Gheber, Ariel Kushmaro, and Shoshana (Mails) Arad. "Complexes of Cu–Polysaccharide of a Marine Red Microalga Produce Spikes with Antimicrobial Activity." Marine Drugs 20, no. 12 (2022): 787. http://dx.doi.org/10.3390/md20120787.

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Metal–polysaccharides have recently raised significant interest due to their multifunctional bioactivities. The antimicrobial activity of a complex of Cu2O with the sulfated polysaccharide (PS) of the marine red microalga Porphyridium sp. was previously attributed to spikes formed on the complex surface (roughness). This hypothesis was further examined here using other Cu–PS complexes (i.e., monovalent-Cu2O, CuCl and divalent-CuO, CuCl2). The nanostructure parameters of the monovalent complexes, namely, longer spikes (1000 nm) and greater density (2000–5000 spikes/µm2) were found to be related to the superior inhibition of microbial growth and viability and biofilm formation. When Escherichia coli TV1061, used as a bioluminescent test organism, was exposed to the monovalent Cu–PS complexes, enhanced bioluminescence accumulation was observed, probably due to membrane perforation by the spikes on the surface of the complexes and consequent cytoplasmic leakage. In addition, differences were found in the surface chemistry of the monovalent and divalent Cu–PS complexes, with the monovalent Cu–PS complexes exhibiting greater stability (ζ-potential, FTIR spectra, and leaching out), which could be related to spike formation. This study thus supports our hypothesis that the spikes protruding from the monovalent Cu–PS surfaces, as characterized by their aspect ratio, are responsible for the antimicrobial and antibiofilm activities of the complexes.

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Sacco, Adriano. "Isonitrile complexes of monovalent manganese." Recueil des Travaux Chimiques des Pays-Bas 75, no. 6 (2010): 646–47. http://dx.doi.org/10.1002/recl.19560750608.

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Schamel, Wolfgang W. A., Ignacio Arechaga, Ruth M. Risueño, et al. "Coexistence of multivalent and monovalent TCRs explains high sensitivity and wide range of response." Journal of Experimental Medicine 202, no. 4 (2005): 493–503. http://dx.doi.org/10.1084/jem.20042155.

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A long-standing paradox in the study of T cell antigen recognition is that of the high specificity–low affinity T cell receptor (TCR)–major histocompatibility complex peptide (MHCp) interaction. The existence of multivalent TCRs could resolve this paradox because they can simultaneously improve the avidity observed for monovalent interactions and allow for cooperative effects. We have studied the stoichiometry of the TCR by Blue Native–polyacrylamide gel electrophoresis and found that the TCR exists as a mixture of monovalent (αβγεδεζζ) and multivalent complexes with two or more ligand-binding TCRα/β subunits. The coexistence of monovalent and multivalent complexes was confirmed by electron microscopy after label fracture of intact T cells, thus ruling out any possible artifact caused by detergent solubilization. We found that although only the multivalent complexes become phosphorylated at low antigen doses, both multivalent and monovalent TCRs are phosphorylated at higher doses. Thus, the multivalent TCRs could be responsible for sensing low concentrations of antigen, whereas the monovalent TCRs could be responsible for dose-response effects at high concentrations, conditions in which the multivalent TCRs are saturated. Thus, besides resolving TCR stoichiometry, these data can explain how T cells respond to a wide range of MHCp concentrations while maintaining high sensitivity.

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Yao, Shenglai, Tibor Szilvási, Yun Xiong, Christian Lorent, Ales Ruzicka, and Matthias Driess. "Bis(silylene)‐Stabilized Monovalent Nitrogen Complexes." Angewandte Chemie International Edition 59, no. 49 (2020): 22043–47. http://dx.doi.org/10.1002/anie.202011598.

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Yao, Shenglai, Tibor Szilvási, Yun Xiong, Christian Lorent, Ales Ruzicka, and Matthias Driess. "Bis(silylene)‐Stabilized Monovalent Nitrogen Complexes." Angewandte Chemie 132, no. 49 (2020): 22227–31. http://dx.doi.org/10.1002/ange.202011598.

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Stępniak, Krystyna, Tadeusz Lis, Elżbieta Łastawiecka, and Anna E. Kozioł. "Cori Ester as the Ligand for Monovalent Cations." Molecules 29, no. 9 (2024): 2133. http://dx.doi.org/10.3390/molecules29092133.

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Gerty T. and Carl F. Cori discovered, during research on the metabolism of sugars in organisms, the important role of the phosphate ester of a simple sugar. Glucose molecules are released from glycogen—the glucose stored in the liver—in the presence of phosphates and enter the blood as α-D-glucose-1-phosphate (Glc-1PH2). Currently, the crystal structure of three phosphates, Glc-1PNa2·3.5·H2O, Glc-1PK2·2H2O, and Glc-1PHK, is known. Research has shown that reactions of Glc-1PH2 with carbonates produce new complexes with ammonium ions [Glc-1P(NH4)2·3H2O] and mixed complexes: potassium–sodium and ammonium–sodium [Glc-1P(X)1.5Na0.5·4H2O; X = K or NH4]. The crystallization of dicationic complexes has been carried out in aqueous systems containing equimolar amounts of cations (1:1; X–Na). It was found that the first fractions of crystalline complexes always had cations in the ratio 3/2:1/2. The second batch of crystals obtained from the remaining mother liquid consisted either of the previously studied Na+, K+ or NH4+ complexes, or it was a new sodium hydrate—Glc-1PNa2·5·H2O. The isolated ammonium–potassium complex shows an isomorphic cation substitution and a completely unique composition: Glc-1PH(NH4)xK1−x (x = 0.67). The Glc-1P2− ligand has chelating fragments and/or bridging atoms, and complexes containing one type of cation show different modes of coordinating oxygen atoms with cations. However, in the case of the potassium–sodium and ammonium–sodium structures, high structural similarities are observed. The 1D and 2D NMR spectra showed that the conformation of Glc-1P2− is rigid in solution as in the solid state, where only rotations of the phosphate group around the C-O-P bonds are observed.

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Kariuki, Benson M., James A. Platts, and Paul D. Newman. "A hybrid bipy–NHC ligand for the construction of group 11 mixed-metal bimetallic complexes." RSC Advances 11, no. 54 (2021): 34170–73. http://dx.doi.org/10.1039/d1ra06581e.

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M., Viswanathan. "Synthesis and characterization of mixed ligand complexes of thorium(IV) with N,N' -propylenebis(3-carboxypropenamide) and various anions." Journal of Indian Chemical Society Vol. 82, Oct 2005 (2005): 871–74. https://doi.org/10.5281/zenodo.5826730.

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Department of Chemistry, S. N. College for Women, Kollam-691 001, India <em>E-mail</em> : jaiviswam@yahoo.co.in                        jaiviswam @sanchamet.in <em>Manuscript received 13 August 2004, revised 17 June 2005, accepted 5 July 2005</em> A new series of mixed ligand complexes of thorium(IV) with N,N'-propylenebis(3-carboxypropenamide) [PBCPH2] and various monovalent anions such as nitrate, perchlorate and thiocyanate have been synthesized. These complexes were characterised by chemical analysis, conductance, magnetic, X-ray powder diffraction, spectral and thermal studies. From these studies the composition of the complexes were ascertained to be [Th(PBCP)X<sub>2</sub>] and [Th(PBCP)(ClO<sub>4</sub>)]0ClO<sub>3</sub>, where X = NO<sup>-</sup><sub>3</sub> or Ncs<sup>-</sup>. In these complexes <em>N,N'</em>-propylenebis(3-carboxypropenamide) acts as a tetradentate ligand and monovalent anions act as unidentate ligands.

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Reed, Brendan, Diana Gil Pages, Ed Palmer, and Adam Schrum. "Reevaluating the biochemical valency of native TCR/CD3 complexes isolated from T cells (IRM7P.708)." Journal of Immunology 194, no. 1_Supplement (2015): 61.9. http://dx.doi.org/10.4049/jimmunol.194.supp.61.9.

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Abstract The αβ T cell antigen Receptor (TCR) is a multi-protein complex expressed together with CD3 subunits (γδεζ). The conventional model has it as monovalent with a stochiometry of (αβγδε2ζ2); however, some previously published work reported observation of bivalent complexes with two αβ heterodimers. To reevaluate the valency of the TCR, we have subjected T cell digitonin-solubilized complexes to immunoprecipitation detected by flow cytometry (IP-FCM), size exclusion chromatography, and other methods for detecting complex size and subunit composition. Our results indicate that precisely bivalent TCRs are found among surface-expressed complexes independent of cross-linking by strong antigenic ligands. Their detection can be masked in the presence of Coomassie reagent from Blue-native PAGE conditions, or if antibodies used in detection assays are themselves bivalent. Therefore, bivalent TCR/CD3 complexes can be found under the biochemical conditions that have classically defined the minimally expressed TCR/CD3 unit (digitonin solubilization). Further investigation is required to determine the functional relevance of these bivalent TCR complexes, although greater antigenic binding and signaling is predicted over that of monovalent TCRs.

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Möller, Nadja, Tim Hellwig, Lucas Stricker, Sabrina Engel, Carsten Fallnich, and Bart Jan Ravoo. "Near-infrared photoswitching of cyclodextrin–guest complexes using lanthanide-doped LiYF4 upconversion nanoparticles." Chemical Communications 53, no. 1 (2017): 240–43. http://dx.doi.org/10.1039/c6cc08321h.

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This communication reports a new type of supramolecular cyclodextrin–guest complexes using cyclodextrin coated upconversion nanoparticles as hosts and monovalent and divalent azobenzenes and arylazopyrazoles as guests.

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Dissertations / Theses on the topic "Monovalent complexes"

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Stephens, Ashley. "Cryptates and pendant arm ligand complexes /." Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phs832.pdf.

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Clarke, Philip. "A study of cryptate complexes and pendant arm ligand complexes /." Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phc5988.pdf.

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Kamras, Brian Leon. "Application-Focused Investigation of Monovalent Metal Complexes for Nanoparticle Synthesis." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1538771/.

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Over the last 20 years, there has occurred an increase in the number, scope, and impact of nanomaterials projects. By leveraging the Surface Plasmon Resonance of metallic nanoparticles for labelling, sensing, and treatment, researchers have demonstrated the versatile utility of these nanomaterials in medicine. The literature provides evidence of use of simple, well-known chemistry for nanomaterials synthesis when the focus is new applications of nanomaterials. A case in point, is the synthesis of metallic nanoparticles, whereby HAuCl4, CuCl2, Cu(acac)2, and AgNO3 are typically employed as nanoparticle precursors. Unfortunately, the use of these precursors limits the number of applications available to these materials - particularly for AuNPs in medicine, where the byproducts of nanoparticle synthesis (most often surface-adsorbed reductants, toxic stabilizers, and growth directors) cause nanoparticles to fail clinical trials. Despite the several thousand publications detailing the advancements in nanoparticle therapeutics, as of 2017, there were only 50 FDA-approved nanoparticle formulations. Less than 10 were based on metallic nanoparticles. This is a problem because many of these nanoparticle therapeutics demonstrate potent cell killing ability and labeling of cells. A solution to this problem may be the use of weakly coordinated, monovalent metal complexes, which require only one electron to reduce them to their metallic state. Further, by designing nanoparticle syntheses around these monovalent complexes, we can employ weaker, environmentally friendly stabilizers. This strategy also forgoes the use of exogenous reducing agents, because the monovalent complexes can be reduced and stabilized by one reagent. Herein we investigate the use of Au(Me2S)Cl, [Cu(MeCN)4]BF4, and AgBF4 with green stabilizers to synthesize a variety of nanomaterials. We find that a range of sizes of spherical particles, as well as a range of sizes of gold triangular prisms can be synthesized by using techniques that follow this strategy.

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HajiAli, Afzali Saba. "Reactivity of Chromium with Aluminates: The Quest for Monovalent Chromium Complexes." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26078.

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Progress in catalytic ethylene oligmerization and polymerization processes creates an enormously valuable and active field in both industry and academic perspective. From the naive point of view, gathering ethylene molecules to generate carbon carbon bonds can be assumed as the no electron, no energy and facile chemical process which results from interaction of several π-electrons but this process never can afford macro- and micromolecule without applying catalysts. It is no wonder that major efforts have been committed to designing novel catalysts to perform poly- and oligomerization processes, both recently and in the past which provide the extensive library of catalysts today. Among all the metals applied in preparation of homogeneous catalysts for ethylene oligo- and polymerization, chromium has been ideal in providing versatile systems in terms of selectivity and activity for oligomer and polymer productions. In the first part of the current work we chose two different ligand systems (iminopyridine and bisiminophosphine) to investigate the activity of their chromium complexes for ethylene oligmerization and polymerization at different conditions. In addition we took on the substantial challenge of explaining the activities through isolation of intermediates during the catalytic runs. The major focus in this part was rationalizing catalytic behaviour of the catalysts through elucidation of metal oxidation state. To fulfill this goal, syntheses of chromium-aluminate complexes in different valence states as well as description ligand-metal interactions were presented. In the second part of this thesis, our mainly focus of study was on the development in the well- established field of radical chemistry of alkylaluminum. Preferential cation radical and diradical formation and exploring their stabilities through both experimental and computational methods will be discussed. Also continuation of this work led us to report unprecedented double alkylation on the ligand system.

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Harris, Lauren Michelle. "Photophysical Properties of Binuclear and Trinuclear Monovalent Coinage Metal Complexes for Applications in Molecular Devices." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703352/.

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Monovalent coinage metal complexes have been of significant interest due to their rich photophysical properties. This dissertation focuses on the design, synthesis, and characterization of gold, silver, and copper phosphors. Chapter 2 investigates new physical and photophysical properties of a gold diphosphine dimer in the solid state. Thermally activated luminescence switching between two structural states is discussed. Chapter 3 includes the photochemistry of closed shell group 11 transition metals with dithiophosphonate and diphosphine ligands as heteroleptic, homoleptic and heterometallic systems. Chapter 4 reports the synthesis and characterization of a cyclic trinuclear gold imidazolate complex with high electron dentistry and π- base properties. The trinuclear gold (I) complexes reactivity with silver(I) and sodium cations is explored. The photochemistry of all complexes are screened for efficiency, emission profiles and lifetimes as potential materials to be used in OLEDs and other molecular devices.

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Weeks, Jennifer Megan. "A structural thermodynamic and equilibrium study of chiral pendant arm triaza macrocyclic ligand complexes: towards the formation of metal-ion activated molecular receptors : a thesis submitted for the degree of Doctor of Philosophy at the University of Adelaide (Faculty of Science) /." Title page, table of contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phw395.pdf.

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Marzak, Saïd. "Complexes du cuivre (i) construits sur le fragment (ms::(4))**(2-) (m=mo,w) : role du ligand thiocyanate dans l'edification de composes heterometalliques a structure infinie." Paris 6, 1988. http://www.theses.fr/1988PA066401.

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Preparation de complexes du type (nr::(4))::(n)(cu::(4)(ncs)::(4)ms::(4)), m=mo, w, r=me, et et n=2 ou 3. Selon la taille du cation, obtention de macrostructures bidimensionnelles ou tridimensionnelles; l'insertion du cation pph::(4)**(+) conduit a la formation d'une structure infinie de chaines lineaires

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Chambron, Jean-Claude. "Synthese et etude de complexes du cuivre (i) et du ruthenium (ii) en vue de la separation intramoleculaire des charges photoinduites." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13092.

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Preparation de 2 macrocycles contenant a la fois des sites chelatants diphenyl-2,9 phenanthroline-1,10 et dialkyl-4,4' ou diaryl-4,4' bipyridine-2,2'. Dans le complexe heterodinucleaire il existe une interaction a l'etat excite entre les 2 metaux

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Menu, Marie-Joëlle. "Nouveaux reactifs dans la chimie des complexes du rhodium, du chrome et du tungstene : les anions diazo rc(n::(2))**(-)." Toulouse 3, 1988. http://www.theses.fr/1988TOU30068.

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Synthese des complexes de rh, cr et w contenant le coordinat diazo en faisant reagir les sels de li des anions rc(n::(2))**(-) sur les complexes metalliques. On a isole: (pme::(3))::(4) rhc(n::(2))sime::(3) (pet::(3))::(3) rhc(n::(2))sime::(3), (pme::(3))::(2) rhc(n::(2))(s)p(n-ipr::(2))::(2). On a mis en evidence un complexe carbenique dimere possedant un groupe ylure, lors de la photolyse de (pet::(3))::(3) rhc(n::(2))sime::(3)

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Tahiri, Mohamed. "Phtalocyanines de fer(i) et de fer(0) : synthese, structure et reactivite." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13043.

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Synthese et caracterisation d'une serie de complexes monoreduits de phtalocyanine de fer de type (fe pc r::(8))**(-) ou r=och::(3), ch::(3), h, cl et cn. On donne les structures par rx de composes monoanioniques et dianionique fe pc**(-) et fe pc**(2-). Proprietes chimiques de fe pc**(2-). De tels especes peuvent etre des modeles d'intermediaires formes dans la reaction de la phenylhydrazine sur la metmyoglobine ou dans le metabolisme de substrats suicides par cytochrome p450

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Books on the topic "Monovalent complexes"

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Habbadi, Nouzha. Activation des petites molecules par les complexes du cobalt: Réaction des complexes monovalents du cobalt et de la trimethylphosphine avec les alcynes vrais. 1986.

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Book chapters on the topic "Monovalent complexes"

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Schebaum, L. O., and P. Jutzi. "Pentamethylcyclopentadienyl Complexes of the Monovalent Group 13 Elements." In ACS Symposium Series. American Chemical Society, 2002. http://dx.doi.org/10.1021/bk-2002-0822.ch002.

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Meyer, Gerd, Muhamet Sehabi, and Ingo Pantenburg. "Coordinative Flexibility of Monovalent Silver in [AgI←L1]L2 Complexes." In Design and Construction of Coordination Polymers. John Wiley & Sons, Inc., 2009. http://dx.doi.org/10.1002/9780470467336.ch1.

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Koshlan, Tatiana, and Kirill Kulikov. "Mathematical Modelling of the Effect of a Monovalent Solution on the Interaction of Protein Molecules." In Mathematical Modeling of Protein Complexes. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-98304-2_4.

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Painter, George R., and Berton C. Pressman. "Cation Complexes of the Monovalent and Polyvalent Carboxylic Ionophores: Lasalocid (X-537A), Monensin, A23187 (Calcimycin), and Related Antibiotics." In Metal Ions in Biological Systems. CRC Press, 2024. http://dx.doi.org/10.1201/9781003573630-9.

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Matsubara, K. "Monovalent Group 10 Organometallic Complexes." In Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-12-820206-7.00146-3.

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"Aa." In Biochemistry and Molecular biology, edited by Dr AD Smith, SP Datta, Dr G. H. Smith, et al. Oxford University PressOxford, 1997. http://dx.doi.org/10.1093/oso/9780198547686.003.0001.

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Abstract A23187 or calcimycin a toxic and weakly antibiotic substanceisolated from cultures of Streptomyces chartreusensis. It is alipophilic 523 Da monocarboxylic acid of complex structure,two molecules of which form stable lipid-soluble complexes atpH 7.4 with one atom of certain divalent metal cations, especiallyMn2+ , Ca2+ , and Mg2+ ; monovalent cations are boundonly weakly. It also forms lipid-soluble complexes with certainamino acids. It is used experimentally as a calcium ionophore.

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Schaab, Jonas, Peter I. Djurovich, and Mark E. Thompson. "Two-coordinate, monovalent copper complexes as chromophores and luminophores." In Advances in Inorganic Chemistry. Elsevier, 2024. http://dx.doi.org/10.1016/bs.adioch.2024.01.001.

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Pankiewicz, R., G. Schroeder, and B. Brzezinski. "Formation of Complexes Between some Lasalocid Esters and the Monovalent Cations Studied by Spectroscopic and the PMS Semiempirical Methods." In Recent Progress in Computational Sciences and Engineering (2 vols). CRC Press, 2006. http://dx.doi.org/10.1201/b12066-85.

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Przybylski, P., and B. Brzezinski. "AMid, PM3 as well as PMS semiempirical studies of Monensin A complexes with monovalent cations and Monensin A hydrates." In Recent Progress in Computational Sciences and Engineering (2 vols). CRC Press, 2006. http://dx.doi.org/10.1201/b12066-89.

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Tamargo, J., E. Delpon, O. Perez, and C. Valenzuela. "Antiarrhythmic action of drugs interacting with sodium channels." In Ion Channel Pharmacology. Oxford University PressOxford, 1998. http://dx.doi.org/10.1093/oso/9780198523604.003.0003.

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Abstract Cardiac cells display a complex action potential which is generated by a sequence of ionic movements across the cell membrane. In most cardiac cells (atrial and ventricular muscle, His-Purkinje system), the rapid depolarizing phase of the cardiac action potential which supports excitability and conduction velocity result from the rapid entry of Na+ ions through voltage-sensitive Na+ channels1--4 Na+ channels are characterized by voltage-dependent activation, rapid inactivation and high selectivity for Na+ ions over other monovalent cations.

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Conference papers on the topic "Monovalent complexes"

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Hassan, Anas M., Emad W. Al-Shalabi, Waleed AlAmeri, Muhammad S. Kamal, Shirish Patil, and Syed M. Shakil Hussain. "New Insights into Hybrid Low Salinity Polymer (LSP) Flooding Through a Coupled Geochemical-Based Modeling Approach." In SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210120-ms.

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Abstract Low Salinity Polymer (LSP) flooding is one of the emerging synergic techniques in enhance oil recovery (EOR). Previous experimental studies showed an exceptional improvement in displacement efficiency, polymer rheology, injectivity, and polymer viscoelasticity. Nevertheless, when it comes to modeling LSP flooding, it is still challenging to develop a mechanistic predictive model that captures polymer-rock-brine interactions. Therefore, this study employs a coupled geochemical-reservoir numerical model to investigate the effect of water chemistry on polymer-brine-rock geochemical interactions during LSP flooding through varying overall salinity as well as the concentrations of monovalent and divalent ions. In this study, the MATLAB Reservoir Simulation Toolbox (MRST) was coupled with a geochemical interface module i.e., pH-Redox-Equilibrium in C programming language (PHREEQC), termed as IPHREEQC. The coupled MRST-IPHREEQC simulator enables simulating the effects on different parameters on polymer viscosity including the Todd-Longstaff mixing model, inaccessible pore volume, permeability reduction, polymer adsorption, salinity, and shear rate. For describing the related geochemistry, the presence of polymer in the aqueous phase was considered by introducing novel solution specie to the Phreeqc database. Using this coupled simulator, several geochemical reactions and parameters can be assessed including rock and injected water compositions, injection schemes, and other polymer characteristics where the focus of this work is on water chemistry. Moreover, different injection schemes were analyzed including low-salinity water, low-salinity polymer injection (1×LSP), and 5-times spiked low-salinity polymer injection (5×LSP) with their related effects on polymer viscosity. The results showed that polymer viscosity during low-salinity polymer flooding is directly affected by calcium (Ca2+) and magnesium (Mg2+) ions and indirectly affected by sulfate ion (SO42−) as a result of polymer-rock-brine interactions on a dolomite rock-forming mineral. Furthermore, the findings showed that monovalent ions such as sodium (Na+) and potassium (K+) have less pronounced effects on the polymer viscosity. However, the release of calcium (Ca2+) and magnesium (Mg2+) ions due to the dissolution of dolomite led to the formation of polymer (acrylic acid, C3H4O2) complexes and consequently, a pronounced decrease in polymer viscosity. In addition, the increase of sulfate ion (SO42−) concentration in the injected LSP solution affects the interactions between the polymer and positively charged aqueous species and leads to less polymer viscosity loss. Additionally, as a de-risking measure for LSP flood designs, estimating the effect of each ion can be highly useful step. The effect of cations is also related to charge ratio (CR), which renders it the key objective to determine the optimum CR ratio at which viscosity loss of LSP flood is avoided or at least minimal. The coupled simulator works as an integrated tool, which is sound, precise, and adaptable with the ability to encapsulate the reactions required for LSP mechanistic modeling. This paper is among the very few, which describe mechanistic geochemical modeling of the low-salinity polymer flooding technique. The coupled simulator provided new insights into understanding the mechanisms controlling LSP flooding. Based on the findings of this work, several successful low salinity-polymer field pilots can be designed.

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Ge, Xiaojing, Ghith Biheri, Abdulmohsin Imqam, Baojun Bai, and Yuwei Zhang. "Experimental Study: Investigating the Anions and Cations’ Effects on the Elasticity of the Anionic and Cationic High Viscosity Friction Reducers." In SPE Western Regional Meeting. SPE, 2023. http://dx.doi.org/10.2118/213048-ms.

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Abstract High viscosity friction reducers (HVFRs) are widely used as friction-reducing agents and proppant carriers during hydraulic fracturing. The reuse of produced water has gained popularity due to environmental and economic benefits. Currently, the field’s most commonly used friction reducers are anionic and cationic HVFRs. Anionic HVFRs are typically pumped with freshwater, while cationic HVFRs are used with high Total Dissolved Solids (TDS) produced water. Cationic friction reducers are believed to have better TDS tolerance, friction reduction performance, and proppant transport capabilities compared to anionic friction reducers under high TDS conditions due to their superior viscoelastic properties. In addition, the impact of different anions and cations on the viscosity of HVFRs has been thoroughly studied, and viscosity reduction mechanisms include charge shielding, increasing the degree of hydrolysis, and forming coordination complexes. However, anions and cations’ effects on the elasticity of HVFRs still remain to be investigated. Besides, most previous experimental studies either do not specify experimental procedures or control the experimental variables well. Therefore, the ultimate objective of this experimental study is to analyze various cations and anions’ effects on the elasticity of anionic and cationic HVFRs comparably and precisely with experimental variables well controlled. Two hypotheses based on anions and cations’ effects on the viscosity of HVFRs are proposed and will be tested in this study. First, the elasticity reduction of anionic HVFRs is mainly due to cations, whereas the elasticity reduction of cationic HVFRs is mainly due to anions. Second, the salts’ effects on the elasticity reduction of HVFRs should follow the same trend as the salts’ effects on the viscosity reduction of HVFRs. For anionic HVFRs, monovalent Alkali metals should have a similar effect; divalent Alkaline earth metals should have a similar effect; transition metals should have the most severe effect. For cationic HVFRs, SO42- should have more pronounced effects than Cl-. To demonstrate both hypotheses, an anionic and a cationic HVFR at 4 gallons per thousand gallons (GPT) were selected and analyzed. The elasticity measurements of both anionic and cationic HVFRs were conducted with deionized (DI) water and various salts respectively. Fe3+ and H+ (or pH) effects were specifically investigated. The results showed both hypotheses were accepted.

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Alanazi, Khalid, R. Mohan, S. S. Kolla, and O. Shoham. "Experimental Study of Monovalent Salt and Hydrochloric Acid Solution Effects on the Stability of Blank Oil-Water Dispersion in Batch Separators." In ASME 2023 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/imece2023-112880.

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Abstract The effect of aqueous phase salinity and acidity on the stability of oil-water dispersion is poorly understood. This is because most research works use complex solutions of mixed monovalent and divalent salts to replicate the composition of brine solution in the aqueous phase of crude oil emulsion. Hence, the relevance of each form of ionic solution cannot be determined without isolating and analyzing a laboratory-created oil-water dispersion. Toward this objective, this study aims to investigate the impact of monovalent salt solution and acidic water on the stability of blank (emulsifier-free) oil-in-water (O/W) and water-in-oil (W/O) emulsion. Fluids were mixed at a constant stirrer speed (2,500 rpm) and time (5 minutes) for each investigated emulsion. Mineral oil (EXXSOL™ D110) and distilled water with density and viscosity ratios of 0.805 and 0.330, respectively, were chosen as the pure fluids. Sodium chloride (NaCl) was used to vary the concentration of monovalent salt (from 1 to 60 g/L) in the aqueous phase, whereas a 1.0 M hydrochloric acid solution was used to alter the acidity (pH = 4.80 to 1.88) of distilled water. Experiments ranging from less than a minute to several hours were conducted using four water cuts (WC = 25%, 50%, 75%, and 90%). The brine and acidic water phase had shown large impacts on the stability of O/W (90% and 75% WC) emulsions but had minor effects on W/O (25% and 50% WC) emulsions.

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CLENCI, Adrian. "Sustainable road mobility with methane gas. Preliminary results of a monovalent spark ignition engine fueled with methane." In FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-caf-026.

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As argued in many papers, from the road mobility point of view, today, there are three major problems facing humanity: (1) greenhouse gas (GHG) emissions, global warming and city pollution; (2) renewable or sustainable sources of energy; and (3) energy security. The above listed 3 problems generated intense discussions at international level on the impact of the road mobility at global scale. It is well acknowledged through many studies that transport is responsible for around a quarter of CO2 emission (GHG) in the EU. About 75% of this CO2 is produced by road transportation, which is a significantly growing sector worldwide, as we all know. Therefore, decarbonization of road transport is a must. Consequently, as it is very well known, today, the automotive industry heavily invests in the zero and ultra-low emission vehicles (ZEV, ULEV) such as battery electric vehicles (BEV) or plug-in hybrid electric vehicles (PHEV). However, the electrification of road transport will certainly not be the single silver bullet at least for medium term. Until the electrification reaches a better cost and performance level and even a better well-to-wheel efficiency, it is our opinion, as well, that the alternative fuels will continue to be important in the future of road transport in order to be possible to meet the objective concerning the reduction of GHG emissions. Out of the currently available alternative fuels, the methane gas is considered to be one of the best substitute for fossil fuels because, on the one hand, it’s compatible with conventional internal combustion engine and, on the other hand, it’s eco-friendly due to its clean nature of combustion. This being the context, this paper is about presenting our project, which consists in developing a road demonstrator fueled with methane, fully optimized for the operation with methane in order to show the complete potential of this alternative fuel. Thus, our road demonstrator fueled with methane will be developed based on a current turbocharged compression ignition (CI) engine, which will be adapted in order to achieve the spark ignition (SI) operation. Consequently, this paper’s aim is to fully describe the transformation of the CI engine into a SI engine fueled with methane along with the preliminary results about its energetic and ecologic performance obtained at the engine test bed. Our project is actually meant to contribute to the increasing of the awareness about the potential of methane as ecofriendly fuel for road mobility and is joining the existing regulations to trigger the interest in methane.

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Ryckewaert, J. J., O. Valiron, I. A. Newton, E. Concord, M. Prenant, and E. Berthier. "STUDIES ON THE INVOLVEMENTOF GPIIb/IIIa COMPLEX IN PLATELET AGGREGATION WITH TWO MONOCLONAL ANTIBODIES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643706.

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The involvement of the glycoproteins IIb/IIIa in the binding of fibrinogen to stimulated platelets and in the aggregation of these cells is well documented. Monoclonal antibodies (MoAb) directedagainst these two glycoproteins are useful probes in functional studies. Two MoAbs have been obtained against thetwo glycoproteins in their heterodimer form. Both MoAbs immunoprecipitate the complex from platelet lysates and only bind to platelets if the complex of the two glycoproteins is not dissociated.Studies onthe effect of the two MoAbs on platelet function have been performed. Firstly CS9,a murine IgG 2a, inhibited the binding of fibrinogen to stimulated platelets and prevented platelet aggregation. Fab CS9 obtained bypapain digestion had a similar activity. The binding of I125 Fab CS9 to resting platelets was similar to that of ADP-stimulated platelets (30 000 MoAbs/platelet). Similar behaviour of MoAbs against GPIIb/IIIa has been repeatedly reported and is considered as evidence that the fibrinogen receptor is the GPIIb/IIIa complex. The second MoAb (CS3),an IgGJ, subtype had a different action on platelet function.Contrary to all other known antibodies directed against the GPIIb/IIIa complex, CS3 or (Fab’2)CS3 induced the bindingof fibrinogen to platelet in the absence ofany plateletstimuli. Washed platelets in the presenceof CS3 underwent immediate and extensive aggregation, even in the absenceof fibrinogen. The stimulatory activity of MoAb CS3 on platelet can be eliminated by PGEJ. Monovalent CS3 (Fab fragment) failed to exhibit the properties of the parent antibody and had no effect on platelet function. The most likely explanation of the action of CS3 on platelet function may be that crosslinking of two GPIIb/IIIa complex mediated by the antibody leads to platelet stimulation. Whetheror not this mechanism is evocative of a physiological event when platelets are stimulated remains to be demonstrated. When both MoAbs are used in combination, the binding of fibrinogen and platelet aggregation are prevented by CS9 despite the stimulatory activity of CS3. Thus both MoAbsareable to bind to the GPIIb/IIIa complexat the same time.

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Nsiah Turkson, Joshua, Muhammad Aslam Md Yusof, Ingebret Fjelde, Yen Adams Sokama-Neuyam, Victor Darkwah-Owusu, and Bennet Nii Tackie-Otoo. "Harnessing Ensemble Learning Techniques for Accurate Interfacial Tension Estimation in Aqueous CO2 Systems." In GOTECH. SPE, 2024. http://dx.doi.org/10.2118/219176-ms.

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Abstract The interfacial tension (IFT) of aqueous CO2 systems plays a critical role in determining CO2 capillary entry pressure, maximum CO2 storage height, and subsurface storage capacity. Conventional methods for measuring IFT are time-consuming and resource-intensive. This study therefore explores the application of ensemble learning techniques: Gradient Boosting (GradBoost) and Light Gradient-boosting Machine (LightGBM), to predict the IFT of aqueous CO2 systems. A comprehensive dataset of 1570 IFT data points, encompassing six features: pressure (0.1–69.51 MPa), temperature (5.2–196.25℃), monovalent and divalent cation molality (0–5 mol/kg), and methane and nitrogen mole fractions (0–80 mol.%), was compiled from the literature. The data was preprocessed and divided into 70%, 15%, and 15% subsets for model training, testing, and validation. Model performance was optimized through regularization and hyperparameter tuning. Statistical metrics and visualizations were employed for quantitative and qualitative evaluation of the models. The Leverage approach was used to identify potential outliers and ensure model reliability. Sensitivity analysis and feature importance were assessed using permutation importance and the Akaike Information Criterion (AIC). GradBoost and LightGBM exhibited remarkable performance, achieving a coefficient of determination (R2) exceeding 0.98, root mean square error (RMSE) below 2.00 mN/m, mean absolute error (MAE) lower than 1.2 mN/m, and average absolute percentage relative error (AAPRE) less than 1.5% for all data groups. GradBoost surpassed LightGBM in terms of accuracy (higher R2 of 0.99), precision (lower MAE of 0.87 mN/m), consistency (lower RMSE of 1.23 mN/m), and complexity (lower AIC of 53). Furthermore, GradBoost outperformed a committee machine intelligent system, a group method of data handling model, and other robust ensemble models such as random forest and adaptive boosting. Permutation importance and AIC revealed that pressure and monovalent cation molality were the least and most influential features on IFT prediction. Additionally, excluding any of the six input features significantly reduced model performance, with AIC increasing by 6 and 9 folds without temperature and pressure data, respectively. The Leverage approach confirmed the statistical validity and reliability of the GradBoost model, identifying only 3% of the total data points as potential outliers. This study demonstrates the effectiveness of ensemble learning techniques in capturing the complex relationships between variables that govern the IFT of aqueous CO2 systems. The constructed ML models offer a rapid and reliable alternative to conventional methods for IFT evaluation, speeding up workflows, and reducing experimental uncertainties. These advancements hold promise for optimizing CO2 storage strategies and enhancing subsurface CO2 storage capacity.

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Untheim, Thomas, Fabian Großmann, Paul Tatucu-Ertel, Marius Jochem, Peter Weigand, and Georgios Bikas. "Experimental Study on Ammonia/OME Combustion in a Dual-Fuel Engine with Emphasis on Highly Diluted Intake Air Conditions." In WCX SAE World Congress Experience. SAE International, 2023. http://dx.doi.org/10.4271/2023-01-0283.

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<div class="section abstract"><div class="htmlview paragraph">Ammonia, which is considered as an excellent hydrogen carrier, could potentially become a clean fuel for direct use in ICE.</div><div class="htmlview paragraph">An experimental setup with a strongly modified inline four-cylinder (I4) heavy duty Diesel engine was used to study different combustion modes of ammonia in ICE. The fourth cylinder of that engine was operated in a monovalent mode using either OME or Diesel fuel. Its complete exhaust stream was fed into the first cylinder of the same engine, which was operated on a dual-fuel mode by utilizing ammonia port injection and OME or Diesel pilot injection to ignite the mixture. The fourth cylinder of the I4 heavy duty engine can be operated at conditions between idle and full load and at different stoichiometries (λ) to impact both the temperature and the oxygen concentration at the exhaust of that cylinder. Since the first cylinder is fed by the complete exhaust stream of the fourth, the intake conditions of the first cylinder can be controlled appropriately and various ammonia combustion modes can be realized.</div><div class="htmlview paragraph">Emissions measurements at the intake and the exhaust of the first cylinder at different speeds and loads show the impact of the different combustion modes, especially due to temperature and oxygen content variations, on NOx and combustion efficiency. Chemical kinetics calculations have been elaborated to explain some of the main observations.</div></div>

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Niiya, K., E. Hodson, R. Bader, V. Byers-Ward, E. F. Plow, and Z. M. Ruggeri. "STIMULUS-DEPENDENT CHANGES IN THE SURFACE EXPRESSION OF GPIIb/IIIa AND FIBRINOGEN RECEPTORS. RELATIONSHIP TO PLATELET AGGREGATION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643957.

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Platelet stimulation altered the binding of three monoclonal antibodies (monovalent Fab’ fragment) directed against the glycoprotein (GP)IIb/IIIa complex. We found that 47,600-60,300 molecules of antibody bound per platelet before stimulation, as compared to 89,200-146,500 molecules per platelet after thrombin stimulation. These changes were observed in parallel with a small but significant increase in the dissociation constant (Kd) of two antibodies. In contrast, no statistically significant changes were observed with ADP-stimulated platelets. The increased binding of LJ-CP3, but not of the other two antibodies, to activated platelets decreased by 3040% in the presence of EDTA at 22-25°C, suggesting the occurrence of divalent-cation mediated, activation-dependent changes in the corresponding GPIIb/IIIa epitope. Platelets stimulated by thrombin bound more fibrinogen than those stimulated by ADP, and significant differences in the extent but not in the affinity of fibrinogen binding were observed with different platelet agonists. When the pool of GPIIb/IIIa molecules exposed on the surface of unstimulated platelets was reacted with monoclonal antibody LJ-CP3 to block ADP-induced fibrinogen binding and platelet aggregation, thrombin stimulation still induced substantial binding and aggregation. This effect of thrombin required exposure of platelets to the active agonist and was not mediated by molecules released by thrombin into the medium. Therefore, platelets activated with “strong” agonists exhibit increased number of surface-oriented epitopes associated with GPIIb/IIIa. The GPIIb/IIIa molecules bearing these newly exposed epitopes are functional in that they bind fibrinogen and mediate platelet aggregation.

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Mitsuuchi, Yasuhiro, Christopher A. Benetatos, Thomas Haimowitz, et al. "Abstract 1806: Birinapant, a bivalent SMAC-mimetic, promotes efficient cellular IAP E3 ligase activity and formation of a pro-apoptotic RIPK1:caspase-8 complex while monovalent IAP inhibitors are less efficient - implications for therapeutic utility." In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-1806.

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Salgia, Ravi, Amy C. Peterson, John Bothos, et al. "Abstract 2774: Complete results from a phase Ia dose-escalation and dose-expansion study of single-agent MetMAb, a monovalent antagonist antibody to the receptor MET, administered intravenously in patients with locally advanced or metastatic solid tumors." In Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC. American Association for Cancer Research, 2010. http://dx.doi.org/10.1158/1538-7445.am10-2774.

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