79 results on '"Pinter B"'
Search Results
2. Dissipative instability in a partially ionised prominence slab
- Author
-
Ballai, I., Pinter, B., Oliver, R., and Alexandrou, M.
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Physics - Plasma Physics - Abstract
We investigate the nature of dissipative instability appearing in a prominence planar thread filled with partially ionised plasma in the incompressible limit. The importance of partial ionisation is investigated in terms of the ionisation factor and wavelength of waves propagating in the slab. To highlight the role of partial ionisation, we have constructed models describing various situations we can meet in solar prominence fine structure. Matching the solutions for the transversal component of the velocity and total pressure at the interfaces between the prominence slab and surrounding plasmas, we derived a dispersion relation whose imaginary part describes the evolution of the instability. Results are obtained in the limit of weak dissipation. We have investigated the appearance of instabilities in prominence dark plumes using single and two-fluid approximations. We show that dissipative instabilities appear for flow speeds that are less than the Kelvin-Helmholtz instability threshold. The onset of instability is determined by the equilibrium flow strength, the ionisation factor of the plasma, the wavelength of waves and the ion-neutral collisional rate. For a given wavelength and for ionisation degrees closer to a neutral gas, the propagating waves become unstable for a narrow band of flow speeds, meaning that neutrals have a stabilising effect. Our results show that the partially ionised plasma describing prominence dark plumes becomes unstable only in a two-fluid (charged particles-neutrals) model, that is for periods that are smaller than the ion-neutral collision time. The present study improves our understanding of stability of solar prominences and the role of partial ionisation in destabilising the plasma. We show the necessity of two-fluid approximation when discussing the nature of instabilities: waves in a single fluid approximation show a great deal of stability., Comment: 12 pages, 11 figures
- Published
- 2017
- Full Text
- View/download PDF
3. Sniffing the diagnosis: Olfactory testing in neurodegenerative parkinsonism
- Author
-
Krismer, F., Pinter, B., Mueller, C., Mahlknecht, P., Nocker, M., Reiter, E., Djamshidian-Tehrani, A., Boesch, S.M., Wenning, G.K., Scherfler, C., Poewe, W., and Seppi, K.
- Published
- 2017
- Full Text
- View/download PDF
4. Nutritional status of women undergoing in vitro fertilization
- Author
-
Trampuš, L., Pinter, B., and Benedik, E.
- Published
- 2024
- Full Text
- View/download PDF
5. EURAMET supplementary comparison on calibration of RF current monitoring probe
- Author
-
Şen, O, primary, Çınar, M, additional, Kriz, A, additional, Pavlíček, T, additional, Lerat, J M, additional, Wojciechowski, M, additional, Pinter, B, additional, Rodríguez, M, additional, and Pythoud, F, additional
- Published
- 2021
- Full Text
- View/download PDF
6. Identification of symbol digit modality test score extremes in Huntington's disease
- Author
-
Braisch, U, Muche, R, Rothenbacher, D, Landwehrmeyer, GB, Long, JD, Bentivoglio, AR, Biunno, I, Bonelli, RM, Dunnett, SB, Illmann, T, Levey, J, Ramos-Arroyo, M, Nielsen, JE, Paivarinta, M, Sebastian, AR, Tabrizi, SJ, Vandenberghe, W, Uhrova, T, Come, A, Garde, MB, Betz, S, Capodarca, S, Wildson, SC, da Silva, V, Di Renzo, M, Finisterra, M, Genoves, C, Gilling, M, Handley, OJ, Hvalstedt, C, Koppers, K, Lamanna, C, Laura, M, Descals, AM, Monza, D, Mutze, L, Oehmen, M, Padieu, H, Paterski, L, Koivisto, SP, Rindal, B, Roren, N, Sasinkova, P, Seliverstov, Y, Timewell, E, Cubillo, PT, van Walsem, MR, Witjes-Ane, MN, Yudina, E, Zielonka, E, Zinzi, P, Braunwarth, EM, Brugger, F, Buratti, L, Hametner, EM, Hepperger, C, Holas, C, Hotter, A, Hussl, A, Larcher, B, Mahlknecht, P, Muller, C, Pinter, B, Poewe, W, Seppi, K, Sprenger, F, Wenning, G, Dupuis, M, Minet, C, Ribai, P, Van Paemel, D, Verellen-Dumoulin, C, Klempir, J, Majerova, V, Roth, J, Babiloni, B, Debruxelles, S, Duche, C, Goizet, C, Jameau, L, Lafoucriere, D, Spampinato, U, Bachoud-Levi, AC, Boisse, MF, de Langavant, LC, Lemoine, L, Morgado, G, Youssov, K, Annic, A, Barthelemy, R, De Bruycker, C, Cabaret, M, Carette, AS, Carriere, N, Decorte, E, Defebvre, L, Delliaux, M, Delval, A, Depelchin, A, Destee, A, Dewulf-Pasz, N, Dondaine, T, Dugauquier, F, Dujardin, K, Lemaire, MH, Manouvrier, S, Peter, M, Plomhause, L, Sablonniere, B, Simonin, C, Tard, C, Thibault-Tanchou, S, Vuillaume, I, Bellonet, M, Benoit, A, Blin, S, Courtin, F, Duru, C, Fasquel, V, Godefroy, O, Krystkowiak, P, Mantaux, B, Roussel, M, Tir, M, Schuler, B, Wannepain, S, Azulay, JP, Chabot, C, Delfini, M, Eusebio, A, Fluchere, F, Grosjean, H, Mundler, L, Nowak, M, Bioux, S, Bliaux, E, Girard, C, Guyant-Marechal, L, Hannequin, D, Hannier, V, Jourdain, S, Maltete, D, Pouliquen, D, Blondeau, L, Calvas, F, Cheriet, S, Delabaere, H, Demonet, JF, Pariente, J, Pierre, M, Beuth, M, Gelderblom, H, Priller, J, Pruss, H, Spruth, E, Thiel, S, Ellrichmannberlin, G, Herrmann, L, Hoffmann, R, Kaminski, B, Saft, C, Bosredon, C, Hunger, U, Lohle, M, Maass, A, Ossig, C, Schmidt, S, Storch, A, Wolz, A, Wolz, M, Kohl, Z, Kozay, C, Ullah, J, Winkler, J, Bergmann, U, Boringer, R, Capetian, P, Kammel, G, Lambeck, J, Meier, S, Rijntjes, M, Zucker, B, Boelmans, K, Ganos, C, Goerendt, I, Heinicke, W, Hidding, U, Munchau, A, Schmalfeld, J, Stubbe, L, Zittel, S, Diercks, G, Dressler, D, Francis, F, Gayde-Stephan, S, Gorzolla, H, Kramer, B, Minschke, R, Schrader, C, Tacik, P, Longinus, B, Lusebrink, A, Muhlau, M, Peinemann, A, Stadtler, M, Weindl, A, Winkelmann, J, Ziegler, C, Bechtel, N, Beckmann, H, Bohlen, S, Gopfert, N, Holzner, E, Lange, H, Reilmann, R, Rohm, S, Rumpf, S, Sass, C, Schepers, S, Weber, N, Barth, K, Buck, A, Connemann, J, Ecker, D, Geitner, C, Held, C, Kesse, A, Landwehrmeyer, B, Lezius, F, Lewerenz, J, Nepper, S, Niess, A, Orth, M, Schneider, A, Schwenk, D, Sussmuth, S, Trautmann, S, Weydt, P, Klebe, S, Musacchio, T, Leypold, C, Noth, K, Cormio, C, de Tommaso, M, Franco, G, Sciruicchio, V, Serpino, C, Calandra-Buonaura, G, Capellari, S, Cortelli, P, Gallassi, R, Poda, R, Sambati, L, Scaglione, C, Maserati, MS, Agosti, C, Barlati, S, Compostella, S, Marchina, E, Padovani, A, Bertini, E, Ghelli, E, Ginestroni, A, Mechi, C, Paganini, M, Piacentini, S, Pradella, S, Romoli, AM, Sorbi, S, Abbruzzese, G, di Poggio, MB, Ferrandes, G, Mandich, P, Marchese, R, Tamburini, T, Baake, V, van den Bogaard, SJA, Bos, R, Dumas, EM, t'Hart, EP, Kampstra, A, Roos, RAC, Schoonderbeek, A, Aaserud, O, Bjorgo, K, Borgeod, N, Dramstad, E, Fannemel, M, Frich, JC, Gorvell, PF, Heiberg, A, Lorentzen, E, Retterstol, L, Rosby, O, Sikiric, A, Stokke, B, van Walsem, M, Wehus, R, Bjornevoll, I, Sando, SB, Haug, MG, Storseth, HH, Arntsen, V, Dziadkiewicz, A, Konkel, A, Narozanska, E, Robowski, P, Sitek, E, Slawek, J, Soltan, W, Szinwelski, M, Arkuszewski, M, Blaszczyk, M, Boczarska-Jedynak, M, Ciach-Wysocka, E, Gorzkowska, A, Nska-Myga, BJ, Kaczmarczyk, A, Klodowska-Duda, G, Opala, G, Stompel, D, Banaszkiewicz, K, Bocwinska, D, Bojakowska-Jaremek, K, Dec, M, Grabska, N, Krawczyk, GM, Kubowicz, E, Malec-Litwinowicz, M, Rudzinska, M, Stenwak, A, Szczudlik, A, Szczygiel, E, Wojcik, M, Wasielewska, A, Bryl, JAA, Ciesielska, A, Klimberg, A, Marcinkowski, J, Samara, H, Sempolowicz, J, Sniewski, BW, Zielonka, D, Gogol, A, Janik, P, Jamrozik, Z, Kaminska, A, Kwiecinski, H, Antczak, J, Jachinska, K, Krysa, W, Rakowicz, M, Richter, P, Rola, R, Ryglewicz, D, Sienkiewicz-Jarosz, H, Stepniak, I, Sulek, A, Witkowski, G, Zaremba, J, Zdzienicka, E, Ziora-Jakutowicz, K, Januario, C, Julio, F, Guedes, LC, Coelho, M, Finisterra, AM, Ferreira, JJ, Mestre, T, Mendes, T, Rosa, MM, Valadas, A, Kopishinskaya, S, Korotysh, M, Herrera, CD, Moreno, PG, Bas, J, Busquets, N, Calopa, M, Classen, SJ, Dedicha, NR, Buongiorno, MT, Maria, ADS, Munoz, E, Santacruz, P, Barbera, MA, Pardo, SA, Guia, DB, Calzado, N, Hernanz, LC, Diaz-Zorita, JPT, Catena, JL, Ferrer, PQ, Carruesco, GT, Robert, MF, Viladrich, CM, Roca, E, Idiago, JMR, Riballo, AV, Campolongo, A, de Bobadilla, RF, Bojarsky, JK, Martinez-Horta, S, Pagonabarraga, J, Perez, JP, Ribosa, R, Villa, C, Gil, MAA, Corrales, KB, Esteban, JCG, Gonzalez, A, Merino, BT, Cubo, E, Polo, CG, Mariscal, N, Romero, SG, Arbelo, JM, de Molina, RM, Martin, I, Perianez, JM, Udaeta, B, Alonso-Frech, F, Frades, B, Villanueva, MA, Sevilla, MAZ, Frech, FA, Fenollar, MD, Garcia, RGR, Villanueva, C, Bascunana, M, Ventura, MF, Ribas, GG, de Yebenes, JG, Moreno, JLLS, Barral, VM, Ruiz, PJG, Garcia, A, Lopez, RG, Barcenas, AH, Martinez-Descals, A, Martin, VP, Martinez, NR, Artiga, MJS, Sanchez, V, Pueyo, A, Gonzalez, S, Guisasola, LM, Ribacoba, MPPR, Salvador, C, Lozano, PS, Caldentey, JG, Ramirez, IL, Arques, PN, Lopera, MR, Pastor, BV, Gaston, I, Garcia-Amigot, F, Martinez-Jaurrieta, MD, Ramos-Arroyo, MA, Carrillo, F, Redondo, MTC, Mir, P, Gonzalez, LV, Moreno, JMG, Lucena, CM, Pena, JC, Redondo, L, Sanchez, VS, Fernandez, CM, Mata, MP, Lemos, MDR, Bosca, M, Burguera, JA, Vilaplana, FCBCP, Solis, P, Figuerola, BJ, Palanca, PM, Berglund, P, Constantinescu, R, Fredlund, G, Hosterey-Ugander, U, Linnsand, P, Neleborn-Lingefjard, L, Wahlstrom, J, Palhagen, S, Svenningsson, P, Paucar, M, Wallden, T, Ekwall, C, Goller, ML, Sundblom, J, Stebler, Y, Kaelin, A, Romero, I, Schupbach, M, Zaugg, SW, Jung, H, Petersen, J, Auer, M, Mihaylova, V, Vernon, N, Akhtar, S, Crooks, J, Curtis, A, de Souza, J, Piedad, J, Rickards, H, Wright, J, Pallett, A, Coulthard, E, Gethin, L, Hayward, B, Sieradzan, K, Wright, A, Busse, M, Butcher, C, Dunnett, S, Clenaghan, C, Hunt, S, Jones, L, Jones, U, Khalil, H, Minster, S, Owen, M, Price, K, Townhill, J, Rosser, A, Edwards, M, Ho, C, McGill, M, Porteous, M, Pearson, P, Harrower, T, Irvine, S, Brockie, P, Foster, J, Johns, N, McKenzie, S, Rothery, J, Thomas, G, Yates, S, Deith, C, Ireland, J, Ritchie, S, Andrew, A, Frost, J, Noad, R, Cosgrove, J, Gallantree, D, Hamer, S, Hobson, E, Jamieson, S, Kraus, A, Longthorpe, M, Markova, I, Musgrave, H, Peacy, C, Raman, A, Rowett, L, Toscano, J, Wild, S, Yardumian, P, Clayton, C, Dipple, H, Freire-Patino, D, Hallam, C, Middleton, J, Alusi, S, Davies, R, Foy, K, Gerrans, E, Leggett, H, Pate, L, Anjum, U, Coebergh, J, Eddy, C, McEntagart, M, Patton, M, Peterson, M, Rose, S, Andrews, T, Brown, S, Bruno, S, Doherty, K, Golding, C, Haider, S, Hensman, D, Lahiri, N, Lewis, M, Novak, M, Patel, A, Robertson, N, Rosser, E, Tabrizi, S, Taylor, R, Warner, T, Wild, E, Arran, N, Bek, J, Callaghan, J, Craufurd, D, Fullam, R, Howard, L, Huson, S, Johnson, L, Jones, M, Krishnamoorthy, A, Murphy, H, Oughton, E, Partington-Jones, L, Rogers, D, Sollom, A, Snowden, J, Stopford, C, Thompson, J, Tinkler, P, Trender-Gerhard, I, Verstraelen, N, Westmoreland, L, Cass, G, Davidson, L, Davison, J, Fullerton, N, Holmes, K, Komati, S, McDonnell, S, Mohammed, Z, Morgan, K, Savage, L, Singh, B, Wood, J, Chu, E, Knight, C, O'Neill, M, Das Purkayastha, D, Nemeth, AH, Siuda, G, Valentine, R, Dixon, K, Armstrong, R, Harrison, D, Hughes, M, Large, S, Donovan, JO, Palmer, A, Parkinson, A, Soltysiak, B, Timings, L, Williams, J, Burn, J, Weekes, R, Craven, J, Bailey, W, Coleman, C, Haig-Brown, D, Simpson, S, Hare, M, Majeed, T, Bandmann, O, Bradbury, A, Fairtlough, H, Fillingham, K, Foustanos, I, Gill, P, Kazoka, M, Nevitt, L, Peppa, N, Quarrell, O, Taylor, C, Tidswell, K, O'Donovan, K, Agarwal, V, Anderson, M, Gunner, K, Harris, K, Hayward, E, Heywood, M, Keys, L, Kipps, C, MacKinnon, L, Smalley, S, Gowers, L, Powell, K, Bethwaite, P, Edwards, R, Fuller, K, Phillips, M, Tan, L, Burgunder, JM, Lau, PN, Pica, E, Shoulson, I, Gusella, JG, Antonijevic, I, vankammen, D, Foroud, T, Warner, J, Giuliano, J, Vetter, L, Marshall, F, Marder, K, Frucht, S, Moskowitz, C, Clouse, R, Wasserman, P, Shannon, K, Jaglin, J, Jankovic, J, Palao, A, Harrison, M, Singer, C, Quesada, M, Hersch, S, Rosas, D, Tanev, K, Malarick, K, Colcher, A, Sanchez-Ramos, J, Kostyk, S, Paulsen, J, Perlmutter, J, Tabbal, S, Ross, C, Dorsey, R, Nucifora, F, Dubinsky, R, Dubinsky, H, Suchowersky, O, Klimek, ML, Jones, R, Morgan, J, Mohlo, E, Kang, U, Agarwal, P, Factor, S, Jennings, D, Higgins, D, Adams, J, Frank, S, Saint-Hilaire, M, Diggin, M, Furtado, S, Walker, F, O'Neill, C, Quaid, K, LeDoux, M, Raymond, L, Leavitt, B, Decolongon, J, Perlman, S, Peavy, G, Goldstein, J, Kumar, R, McCusker, E, Griffith, J, Loy, C, Wheelock, V, Tempkin, T, Martin, A, Nance, M, Mallonee, W, Suter, G, Revilla, F, Gartner, M, Drazinic, C, Fitzpatrick, MJ, Panisset, M, Duff, K, Scott, B, Weiner, W, Robottom, B, Chiu, E, Yastrubetskaya, O, Churchyard, A, Greenamyre, TJ, Oakes, D, Beck, C, Robertson, S, Eaton, K, Lindsay, P, Deuel, L, MacDonald, M, Hickey, C, Muratori, L, Leserman, A, Doucette, N, Uc, E, Rodnitzky, R, Vik, S, Davis, R, Dietrich, S, Segro, V, Erickson, D, Hunt, V, Lucarelli, N, Broyles, J, Delarosa, J, Louis, E, Panegyres, P, Schmidt, A, Barton, S, Sperin, E, Testa, C, Thiede, F, Zauber, SE, McInnis, R, Welsh, C, Wesson, M, Coleman, A, and European Commission
- Subjects
Adult ,Male ,congenital, hereditary, and neonatal diseases and abnormalities ,COHORT ,Cox hazard model ,quantile regression ,REGISTRY ,symbol digit modalities test ,Genotype ,Neuropsychological Tests ,Cohort Studies ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Cognition ,0302 clinical medicine ,Huntington's disease ,Rating scale ,mental disorders ,medicine ,Humans ,Verbal fluency test ,Longitudinal Studies ,Genetics (clinical) ,Proportional Hazards Models ,030304 developmental biology ,0303 health sciences ,Proportional hazards model ,business.industry ,Reproducibility of Results ,Middle Aged ,medicine.disease ,nervous system diseases ,Psychiatry and Mental health ,Huntington Disease ,Phenotype ,Test score ,Cohort ,Disease Progression ,Female ,Observational study ,business ,030217 neurology & neurosurgery ,Stroop effect ,Clinical psychology - Abstract
REGISTRY Investigators of the European Huntington's Disease Network and COHORT Investigators of the Huntington Study Group., Studying individuals with extreme phenotypes could facilitate the understanding of disease modification by genetic or environmental factors. Our aim was to identify Huntington's disease (HD) patients with extreme symbol digit modality test (SDMT) scores. We first examined in HD the contribution of cognitive measures of the Unified Huntington's Disease Rating Scale (UHDRS) in predicting clinical endpoints. The language-independent SDMT was used to identify patients performing very well or very poorly relative to their CAG and age cohort. We used data from REGISTRY and COHORT observational study participants (5,603 HD participants with CAG repeats above 39 with 13,868 visits) and of 1,006 healthy volunteers (with 2,241 visits), included to identify natural aging and education effects on cognitive measures. Separate Cox proportional hazards models with CAG, age at study entry, education, sex, UHDRS total motor score and cognitive (SDMT, verbal fluency, Stroop tests) scores as covariates were used to predict clinical endpoints. Quantile regression for longitudinal language-independent SDMT data was used for boundary (2.5% and 97.5% quantiles) estimation and extreme score analyses stratified by age, education, and CAG repeat length. Ten percent of HD participants had an extreme SDMT phenotype for at least one visit. In contrast, only about 3% of participants were consistent SDMT extremes at two or more visits. The thresholds for the one-visit and two-visit extremes can be used to classify existing and new individuals. The identification of these phenotype extremes can be useful in the search for disease modifiers., This work was in part funded by a grant from the EuropeanCommission under the 7th framework programme (RD-Connect, grantagreement number 305444).
- Published
- 2019
- Full Text
- View/download PDF
7. Managing pregancy after miomectomy in early pregnancy
- Author
-
Eda Vrtačnik-Bokal, Požlep B, Vidmar Šimic M, Helena Ban Frangež, Tul N, and Pinter B
- Subjects
medicine.medical_specialty ,biology ,Obstetrics ,business.industry ,Pelvic inflammatory disease ,biology.protein ,medicine ,Early pregnancy factor ,business - Published
- 2019
- Full Text
- View/download PDF
8. Revealing the thermodynamic driving force for ligand-based reductions in quinoids; conceptual rules for designing redox active and non-innocent ligands† †Electronic supplementary information (ESI) available: Computational protocols and equilibrium structures. See DOI: 10.1039/c5sc01140j
- Author
-
Skara, G., Pinter, B., Geerlings, P., and De Proft, F.
- Subjects
Chemistry - Abstract
The easy reduction of quinoid ligands is driven thermodynamically by superior M–L electrostatics and σ-bonding in the reduced form., Metal and ligand-based reductions have been modeled in octahedral ruthenium complexes revealing metal–ligand interactions as the profound driving force for the redox-active behaviour of orthoquinoid-type ligands. Through an extensive investigation of redox-active ligands we revealed the most critical factors that facilitate or suppress redox-activity of ligands in metal complexes, from which basic rules for designing non-innocent/redox-active ligands can be put forward. These rules also allow rational redox-leveling, i.e. the moderation of redox potentials of ligand-centred electron transfer processes, potentially leading to catalysts with low overpotential in multielectron activation processes.
- Published
- 2015
9. Dissipative instability in a partially ionised prominence plasma slab
- Author
-
Ballai, I., Pinter, B., Oliver, R., and Alexandrou, M.
- Published
- 2017
10. Evaluation of JIG Calibration Method for Absorbing Clamp Calibration According to CISPR 16-1-3
- Author
-
Kokalj, M., primary, Berginc, M., additional, Pinter, B., additional, Voljc, B., additional, and Lindic, M., additional
- Published
- 2018
- Full Text
- View/download PDF
11. Impedance measurements up to 13 MHz
- Author
-
Ziade, F., primary, Kokalj, M., additional, and Pinter, B., additional
- Published
- 2016
- Full Text
- View/download PDF
12. Venusian Bow Shock as Seen by the ASPERA-4 Ion Instrument on Venus Express
- Author
-
Whittaker, I., Guymer, G., Grande, M., Pinter, B., Barabash, S., Federov, A., Mazelle, C., Sauvaud, J.-A., Lundin, R., Russell, C. T., 二穴, 喜文, Franz, M., Zhang, T. L., Andersson, H., Grigoriev, A., Holmstrom, M., Yamauchi, M., 淺村, 和史, Baumjohann, W., Lammer, H., Coates, A. J., Kataria, D. O., Linder, D. R., Curtis, C. C., Hsieh, K. C., Koskinen, H. E. J., Kallio, E., Riihela, P., Schmidt, W., Kozyra, J., Futaana, Y., Asamura, Kazushi, Whittaker, I., Guymer, G., Grande, M., Pinter, B., Barabash, S., Federov, A., Mazelle, C., Sauvaud, J.-A., Lundin, R., Russell, C. T., 二穴, 喜文, Franz, M., Zhang, T. L., Andersson, H., Grigoriev, A., Holmstrom, M., Yamauchi, M., 淺村, 和史, Baumjohann, W., Lammer, H., Coates, A. J., Kataria, D. O., Linder, D. R., Curtis, C. C., Hsieh, K. C., Koskinen, H. E. J., Kallio, E., Riihela, P., Schmidt, W., Kozyra, J., Futaana, Y., and Asamura, Kazushi
- Abstract
著者人数: 43名, Accepted: 2010-04-28
- Published
- 2015
13. Adapter and method for improving the LISN input impedance measurement accuracy
- Author
-
Ziade, F., primary, Ouameur, M., additional, Belieres, D., additional, Poletaeff, A., additional, Allal, D., additional, Kokalj, M., additional, and Pinter, B., additional
- Published
- 2015
- Full Text
- View/download PDF
14. Effect of the oral intake of astaxanthin on semen parameters in patients with oligo-astheno-teratozoospermia: a randomized double-blind placebo-controlled trial
- Author
-
Kumalic Senka Imamovic, Klun Irma Virant, Bokal Eda Vrtacnik, and Pinter Bojana
- Subjects
antioxidant ,male infertility ,oligo-astheno-teratozoospermia ,semen quality ,dna fragmentation ,cancer ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 - Abstract
Higher concentrations of seminal reactive oxygen species may be related to male infertility. Astaxanthin with high antioxidant activity can have an impact on the prevention and treatment of various health conditions, including cancer. However, efficacy studies on astaxanthin in patients with oligospermia with/without astheno- or teratozoospermia (O±A±T) have not yet been reported. Our aim was to evaluate the effect of the oral intake of astaxanthin on semen parameters.
- Published
- 2020
- Full Text
- View/download PDF
15. The outcomes of pregnancy and childbirth in adolescents in Slovenia
- Author
-
Korenčan Simona, Pinter Bojana, Grebenc Mojca, and Verdenik Ivan
- Subjects
teenagers ,delivery ,birth ,labour ,complications ,newborn ,birth weight ,gestational weight gain ,adolescentke ,najstnice ,porod ,rojstvo ,zapleti ,novorojenčki ,porodna teža ,pridobitev telesne teže ,Public aspects of medicine ,RA1-1270 - Abstract
The objective of the study was to determine the course and outcomes of pregnancy and childbirth in adolescents compared to women aged 20–24 years in Slovenia.
- Published
- 2017
- Full Text
- View/download PDF
16. A computational study on the effect of structural isomerism on the excited state lifetime and redox energetics of archetype iridium photoredox catalyst platforms [Ir(ppy)2(bpy)]+ and Ir(ppy)3.
- Author
-
Gómez Bustos D, Sreenivasan S, and Pinter B
- Abstract
This study investigates the impact of structural isomerism on the excited state lifetime and redox energetics of heteroleptic [Ir(ppy)2(bpy)]+ and homoleptic Ir(ppy)3 photoredox catalysts using ground-state and time-dependent density functional theory methods. While the ground- and excited-state reduction potentials differ only slightly among the isomers of these complexes, our findings reveal significant variations in the radiative and non-radiative decay rates of the reactivity-controlling triplet 3MLCT states of these closely related species. The observed differences in radiative decay rates could be traced back to variations in the transition dipole moment, vertical energy gaps, and spin-orbit coupling of the isomers. In [Ir(ppy)2(bpy)]+, transition dipole moment differences play a significant role in controlling the relative lifetime of the triplet states, which we rationalized by a vectorial analysis of permanent dipole moments of the ground and excited states. Regarding the two isomers of Ir(ppy)3, changes in radiative decay rates were primarily attributed to variations in vertical energy gaps and intensity borrowing from other singlet-singlet transitions driven by spin-orbit coupling. Non-radiative decay variations were assessed in terms of differences in reorganization energies, adiabatic energy gap, and spin-orbit coupling. For both complexes, reorganization energies associated with low-energy molecular vibrations and metal-ligand bond length changes following the de-excitation process were major contributors. These insights provide a deeper understanding of how molecular design can be leveraged to optimize the performance of iridium-based photoredox catalysts, potentially guiding the development of more efficient catalytic systems for future applications., (© 2025 Author(s). Published under an exclusive license by AIP Publishing.)
- Published
- 2025
- Full Text
- View/download PDF
17. Photophysics of Molecular Probes for Amyloid-β Detection: Computational Insights into the Roles of Probe Linker and Functional Groups.
- Author
-
Molina-Aguirre G, Chakraborty S, Košmrlj J, Vuković L, and Pinter B
- Subjects
- Fluorescent Dyes chemistry, Molecular Structure, Photochemical Processes, Machine Learning, Amyloid beta-Peptides chemistry, Density Functional Theory
- Abstract
In this computational study, density functional theory (DFT) and time-dependent DFT methods (TD-DFT) were employed to study the optical properties of six families of molecules with donor (D), bridge (B), and acceptor (A) fragments that have potential for use as fluorescent molecular probes for the early detection of Alzheimer's disease. After validating our computational method against experimental data, using X-ray and absorption data, the equilibrium geometries and wave functions of the ground and first singlet excited states were systematically studied. Our simulations demonstrate that the S
1 states of these rod-like D-B-A fluorescent probes are twisted intramolecular charge transfer states with a predominant highest occupied molecular orbital-least unoccupied molecular orbital (HOMO-LUMO) character, the former localized primarily at the donor, whereas the latter at the acceptor site. Moreover, the influence of the bridge, donor, and acceptor fragments on molecules' absorption energies is explored, highlighting the influence of double and triple bonds and some specific modifications on the acceptor side, including the addition of electronegative atoms, pyranone derivatives, and their functionalization. By having the absorption energies of 324 probes in hand, machine learning models were trained to predict the absorption energies of molecules. The models were found to be predictive, which suggests a potential that predictive models for other crucial properties, such as emission and quantum yield, can also be trained if suitable training data sets are made available.- Published
- 2024
- Full Text
- View/download PDF
18. Divalent Titanium via Reductive N-C Coupling of a Ti IV Nitrido with π-Acids.
- Author
-
Bhunia M, Sandoval-Pauker C, Fehn D, Grant LN, Senthil S, Gau MR, Ozarowski A, Krzystek J, Telser J, Pinter B, Meyer K, and Mindiola DJ
- Abstract
The nitrido-ate complex [(PN)
2 Ti(N){μ2 -K(OEt2 )}]2 (1) (PN- =(N-(2-Pi Pr2 -4-methylphenyl)-2,4,6-Me3 C6 H2 ) reductively couples CO and isocyanides in the presence of DME or cryptand (Kryptofix222), to form rare, five-coordinate TiII complexes having a linear cumulene motif, [K(L)][(PN)2 Ti(NCE)] (E=O, L=Kryptofix222, (2); E=NAd, L=3 DME, (3); E=Nt Bu, L=3 DME, (4); E=NAd, L=Kryptofix222, (5)). Oxidation of 2-5 with [Fc][OTf] afforded an isostructural TiIII center containing a neutral cumulene, [(PN)2 Ti(NCE)] (E=O, (6); E=NAd (7), Nt Bu (8)) and characterization by CW X-band EPR spectroscopy, revealed unpaired electron to be metal centric. Moreover, 1e- reduction of 6 and 7 in the presence of Kryptofix222cleanly reformed corresponding discrete TiII complexes 2 and 5, which were further characterized by solution magnetization measurements and high-frequency and -field EPR (HFEPR) spectroscopy. Furthermore, oxidation of 7 with [Fc*][B(C6 F5 )4 ] resulted in a ligand disproportionated TiIV complex having transoid carbodiimides, [(PN)2 Ti(NCNAd)2 ] (9). Comparison of spectroscopic, structural, and computational data for the divalent, trivalent, and tetravalent systems, including their15 N enriched isotopomers demonstrate these cumulenes to decrease in order of backbonding as TiII →TiIII →TiIV and increasing order of π-donation as TiII →TiIII →TiIV , thus displaying more covalency in TiIII species. Lastly, we show a synthetic cycle whereby complex 1 can deliver an N-atom to CO and CNAd., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)- Published
- 2024
- Full Text
- View/download PDF
19. Probing Alzheimer's pathology: Exploring the next generation of FDDNP analogues for amyloid β detection.
- Author
-
Rejc L, Knez D, Molina-Aguirre G, Espargaró A, Kladnik J, Meden A, Blinc L, Lozinšek M, Jansen-van Vuuren RD, Rogan M, Martek BA, Mlakar J, Dremelj A, Petrič A, Gobec S, Sabaté R, Bresjanac M, Pinter B, and Košmrlj J
- Subjects
- Humans, Peptide Fragments metabolism, Peptide Fragments cerebrospinal fluid, Brain metabolism, Brain pathology, Brain diagnostic imaging, Molecular Docking Simulation, Molecular Dynamics Simulation, Plaque, Amyloid metabolism, Plaque, Amyloid pathology, Microscopy, Fluorescence methods, Alzheimer Disease metabolism, Alzheimer Disease diagnosis, Alzheimer Disease pathology, Amyloid beta-Peptides metabolism, Fluorescent Dyes chemistry
- Abstract
Fluorescent probes are a powerful tool for imaging amyloid β (Aβ) plaques, the hallmark of Alzheimer's disease (AD). Herein, we report the synthesis and comprehensive characterization of 21 novel probes as well as their optical properties and binding affinities to Aβ fibrils. One of these dyes, 1Ae, exhibited several improvements over FDDNP, an established biomarker for Aβ- and Tau-aggregates. First, 1Ae had large Stokes shifts (138-213 nm) in various solvents, thereby reducing self-absorption. With a high quantum yield ratio (φ(dichloromethane/methanol) = 104), 1Ae also ensures minimal background emission in aqueous environments and high sensitivity. In addition, compound 1Ae exhibited low micromolar binding affinity to Aβ fibrils in vitro (K
d = 1.603 µM), while increasing fluorescence emission (106-fold) compared to emission in buffer alone. Importantly, the selective binding of 1Ae to Aβ1-42 fibrils was confirmed by an in cellulo assay, supported by ex vivo fluorescence microscopy of 1Ae on postmortem AD brain sections, allowing unequivocal identification of Aβ plaques. The intermolecular interactions of fluorophores with Aβ were elucidated by docking studies and molecular dynamics simulations. Density functional theory calculations revealed the unique photophysics of these rod-shaped fluorophores, with a twisted intramolecular charge transfer (TICT) excited state. These results provide valuable insights into the future application of such probes as potential diagnostic tools for AD in vitro and ex vivo such as determination of Aβ1-42 in cerebrospinal fluid or blood., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF
20. Towards structurally versatile mesoionic N-heterocyclic olefin ligands and their coordination to palladium, gold, and boron hydride.
- Author
-
Ževart T, Pinter B, Lozinšek M, Urankar D, Jansen-van Vuuren RD, and Košmrlj J
- Abstract
We have developed an efficient and versatile approach for the synthesis of a family of 1,2,3-triazole-based mesoionic N-heterocyclic olefin (mNHO) ligands and investigated their coordination to palladium, gold, and boron hydride experimentally and computationally. We reacted mNHOs obtained through deprotonation of the corresponding methylated and ethylated 1,3,4-triaryl-1,2,3-triazolium salts with [Pd(allyl)Cl]
2 to give the corresponding [Pd(η3 -allyl)Cl(mNHO)] coordination complexes.13 C NMR data revealed the strong σ-donor character of the mNHO ligands, consistent with the calculated bond orders and atom-condensed charges. Furthermore, we also synthesized [AuCl(mNHO)] and a BH3 -mNHO adduct by reacting the triazolium salts with AuCl(SMe2 ) and BH3 ·THF, respectively. The BH3 -mNHO adduct was tested in the reduction of select aldehydes and ketones to alcohols.- Published
- 2024
- Full Text
- View/download PDF
21. Fusion Position-Dependent Aromatic Transitions of Ligand Backbone Rings for Controlling the Redox Energetics of Photoredox Catalysts.
- Author
-
Girnt P, Molina-Aguirre G, Gomez Bustos D, Sandoval Pauker C, Vuković L, and Pinter B
- Abstract
To reveal, quantify, and rationalize the effect of backbone π-extension on ligand redox activity, we studied the ground- and excited-state reduction potentials of eight ruthenium photoredox catalysts with the formula Ru(ppy)
2 L (L is the redox-active ligand of the bipyridine family) using density functional theory. Our research underlines the profound importance of the fusion position of backbone aromatic C6 rings on the redox activity of ligands in transition metal photoredox catalysts. Namely, certain fusion positions lead to the dearomatization of C6 rings in ligand-centered electron transfer events, resulting in a thermodynamic penalty equivalent to a half-volt negative shift in the reduction potential. Contrarily, the extent of backbone delocalization shows a minimal impact on redox energetics, which can be explained by the charge concentration at the nitrogen contact atoms in ligand-centered reductions. Grounded in Caulton's conceptual framework, we reaffirm the predictive potency of Lewis structures in ligand-centered redox energetics with qualitative and quantitative data. Our hypothesis regarding the effect of backbone ring dearomatization on redox energetics is further corroborated using magnetic and structure-based aromaticity indicators. Highlighting fusion-dependent dearomatization as a determining factor of ligand-centered electron transfer energetics, our findings hold implications for molecular-level design in advanced electroactive materials and catalysts.- Published
- 2024
- Full Text
- View/download PDF
22. The psychology of intergroup relations was grounded in intragroup processes.
- Author
-
Montoya RM and Pinter B
- Subjects
- Humans, Interpersonal Relations, Group Processes
- Abstract
Although Glowacki proposed that peace developed from the relatively recent advent of intergroup norms and tolerance for out-group members, we submit that (a) positive intergroup relations developed from a psychology grounded in the regulation of intragroup relations, (b) the "default" intergroup orientation is uncertainty, and (c) positive intergroup relations likely existed early in our evolutionary history.
- Published
- 2024
- Full Text
- View/download PDF
23. Heavy Metals and Essential Elements in Association with Oxidative Stress in Women with Polycystic Ovary Syndrome-A Systematic Review.
- Author
-
Srnovršnik T, Virant-Klun I, and Pinter B
- Abstract
Altered levels of heavy metals and essential elements have been associated with oxidative stress (OS) and metabolic and hormonal changes in women with polycystic ovary syndrome (PCOS). We aimed to summarize the knowledge on the association of heavy metals and essential elements with OS in PCOS. An electronic literature search using PubMed for studies published between January 2008 and April 2023 was conducted. We evaluated heavy metals and essential elements in relation to OS in PCOS in 15 articles. PCOS women had increased antimonium (Sb), cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), tellurium (Te), thallium (Tl) and osmium (Os) blood levels and decreased zinc (Zn) blood levels; the results of copper (Cu) blood levels were conflicting. Some studies showed a significant correlation between heavy metals (Sb, Cd, Pb, Hg, As, Te and Tl) and essential elements (Se, Zn, Cr, Ca, Mg and Cu) and markers of OS and chronic inflammation. Heavy metals (Sb, Cd, Pb and Hg) and essential elements (Zn, Cr, Se, Ca, Mg and Cu) were associated with metabolic and hormonal characteristics in PCOS. There might be a possible benefit from supplementation therapy in reducing OS and endocrinological problems related to PCOS. Our review confirmed an association between heavy metals and essential elements with OS in PCOS women. This systematic review is registered in PROSPERO under number CRD42023418453.
- Published
- 2023
- Full Text
- View/download PDF
24. Pathology of the Placenta in Singletons after Assisted Reproductive Technology Compared to Singletons after Spontaneous Conception: A Systematic Review.
- Author
-
Belak U, Pinter B, Ban Frangež H, Velikonja M, and Korošec S
- Subjects
- Pregnancy, Female, Humans, Reproductive Techniques, Assisted adverse effects, Pregnancy Outcome, Placenta, Pregnancy Complications
- Abstract
Background: We reviewed the literature comparing the pathological characteristics of singleton births conceived after assisted reproductive technology (ART) with those after spontaneous conception. Methods: We reviewed PubMed, EMBASE, Ovid MEDLINE, Google Scopus, Scholar, Cochrane Central Register of Controlled Trials and the Web of Science for the previous 10 years, up to November 2022. Results: Four eligible studies included 3445 placentas, 806 after ART (IVF/ICSI). Placentas after ART differed in frequency of retroplacental and marginal hematomas ( p = 0.04), increased thickness ( p = 0.02), higher overall occurrences of vascular and anatomical pathology ( p < 0.001) and more frequent marginal ( p = 0.001) and membranous ( p = 0.02) umbilical cord insertion than placentas from non-ART pregnancies. Conclusion: Further research is needed to determine the extent to which these placental changes in ART pregnancies alter its function and pregnancy outcome.
- Published
- 2023
- Full Text
- View/download PDF
25. Polycystic Ovary Syndrome and Endocrine Disruptors (Bisphenols, Parabens, and Triclosan)-A Systematic Review.
- Author
-
Srnovršnik T, Virant-Klun I, and Pinter B
- Abstract
Exposure to endocrine disrupting chemicals (EDCs) can result in alterations of the female reproductive system, including polycystic ovary syndrome (PCOS). The aim of this review was to summarize the knowledge about the association of EDCs (bisphenols, parabens, and triclosan) with PCOS. We conducted an electronic literature search using PubMed for studies published between January 2007 and October 2022 on EDCs related to PCOS, and evaluated the association of PCOS with bisphenols, parabens and triclosan in 15 articles. Most studies revealed significantly higher plasma, urinary or follicular fluid levels of bisphenol A (BPA) in women with PCOS, and some showed a positive correlation of BPA with insulin resistance, polycystic morphology on ultrasound, hepatic steatosis, bilirubin levels, as well as free androgen index, androstenedione and testosterone serum levels, and markers of low-grade chronic inflammation. There was a negative correlation of BPA with markers of ovarian reserve, sex hormone binding globulin and vitamin D-binding protein. Parabens and triclosan have been studied in only one study each, with no significant associations with PCOS observed. Our review revealed an association of BPA with PCOS and negative effects of BPA on human ovaries; more research is needed to assess the potential associations of parabens and triclosan with PCOS.
- Published
- 2023
- Full Text
- View/download PDF
26. Mechanistic Insights into the Oxidative and Reductive Quenching Cycles of Transition Metal Photoredox Catalysts through Effective Oxidation State Analysis.
- Author
-
Medina E, Sandoval-Pauker C, Salvador P, and Pinter B
- Abstract
The electronic structures of the ground and excited electronic states involved in the oxidative and reductive quenching cycles of 12 relevant ruthenium, iridium, and copper photoredox catalysts ( S
0 , T1 , Dox , and Dred ) are characterized using the recently developed effective oxidation state (EOS) analysis, allowing the monitoring of metal and ligand oxidation states (OSs) along the catalytic cycles. The formal oxidation state assignments derived from the EOS analysis are in agreement with those commonly assumed for these complexes in both ground and excited states. Rather clean and separate ligand- and metal-centered redox events along the different quenching cycles are observed in most of the studied molecular systems. The reliability index obtained for the OS assignations can be readily interpreted in terms of the ionic/covalent character of metal-ligand interactions and ligand non-innocent character. In addition, EOS analysis reveals the high-degree localization of the ligand-centered redox event to one or two redox-active ligand(s) in heteroleptic complexes. Ligand- and metal-condensed spin populations were also computed and analyzed for all the open-shell species involved in this study, showing promises for rapid oxidation state assignments in certain systems, especially Ru complexes, however, suffering from severe defects in other cases.- Published
- 2022
- Full Text
- View/download PDF
27. Terminal and Super-Basic Parent Imides of Hafnium.
- Author
-
Bhunia M, Sandoval-Pauker C, Jafari MG, Grant LN, Gau MR, Pinter B, and Mindiola DJ
- Abstract
A dinuclear hafnium complex containing the parent imido ligand [(PN)(PNC)Hf=NH{μ
2 -K}]2 (2) (PN- =(N-(2-Pi Pr2 -4-methylphenyl)-2,4,6-Me3 C6 H2 ; PNC2- =(N-(2-Pi Pr2 -4-methylphenyl)-2,4,6-CH2 Me2 C6 H2 ), was prepared by reduction of the bisazide trans-[(PN)2 Hf(N3 )2 ] (1) with two equiv of KC8 . Encapsulation of K+ in 2 with crown-ether or cryptand affords the first discrete salt [K(encap)][(PN)(PNC)Hf≡NH] (encap=18-crown-6(THF)2 , 3; 2,2,2-Kryptofix, 4), featuring a terminal parent imide and possessing some of the shortest Hf-N bond lengths known to date. DFT calculations revealed formation of 2 to proceed via an extremely basic monomeric nitrido, [(PN)2 Hf≡N]- (A), having a computed pKBH+ of ∼57 followed by heterolytic splitting of an inert 1,2-CH bond of a benzylic methyl group across the Hf≡N triple bond in A. An electronic structure analysis reveals A to possess a covalent Hf≡N triple bond and of super-basic character. We also showcase reactivity of the Hf≡NH bond with various electrophiles., (© 2022 Wiley-VCH GmbH.)- Published
- 2022
- Full Text
- View/download PDF
28. Electronic structure analysis of copper photoredox catalysts using the quasi-restricted orbital approach.
- Author
-
Sandoval-Pauker C and Pinter B
- Subjects
- Ligands, Oxidation-Reduction, Copper chemistry, Electronics
- Abstract
In this computational study, the electronic structure changes along the oxidative and reductive quenching cycles of a homoleptic and a heteroleptic prototype Cu(I) photoredox catalyst, namely, [Cu(dmp)
2 ]+ (dmp = 2,9-dimethyl-1,10-phenanthroline) and [Cu(phen)(POP)]+ (POP = bis [2-(diphenylphosphino)phenyl]ether), are scrutinized and characterized using quasi-restricted orbitals (QROs), electron density differences, and spin densities. After validating our density functional theory-based computational protocol, the equilibrium geometries and wavefunctions (using QROs and atom/fragment compositions) of the four states involved in photoredox cycle (S0 , T1 , Dox , and Dred ) are systematically and thoroughly described. The formal ground and excited state ligand- and metal-centered redox events are substantiated by the QRO description of the open-shell triplet metal-to-ligand charge-transfer (3 MLCT) (d9 L-1 ), Dox (d9 L0 ), and Dred (d10 L-1 ) species and the corresponding structural changes, e.g., flattening distortion, shortening/elongation of Cu-N/Cu-P bonds, are rationalized in terms of the underlying electronic structure transformations. Among others, we reveal the molecular-scale delocalization of the ligand-centered radical in the3 MLCT (d9 L-1 ) and Dred (d9 L-1 ) states of homoleptic [Cu(dmp)2 ]+ and its localization to the redox-active phenanthroline ligand in the case of heteroleptic [Cu(phen)(POP)]+ .- Published
- 2022
- Full Text
- View/download PDF
29. From Oxidative Stress to Male Infertility: Review of the Associations of Endocrine-Disrupting Chemicals (Bisphenols, Phthalates, and Parabens) with Human Semen Quality.
- Author
-
Virant-Klun I, Imamovic-Kumalic S, and Pinter B
- Abstract
Exposure to endocrine-disrupting chemicals (EDCs) may result in oxidative stress and endocrine system disturbance, which can have an impact on human reproduction and development. In male reproductive health, EDCs have been related to impaired reproductive function and male infertility, altered fetal development, and testicular germ-cell, prostate, and breast cancers. We conducted an electronic search using PubMed on endocrine disruptors related to oxidative stress and male infertility, and evaluated their association with endocrine-disrupting chemicals (bisphenols, phthalates, and parabens) in 25 articles. Higher levels of urinary bisphenols showed correlation with impaired semen quality and increased DNA damage. Considering phthalates and their metabolites, all studies found a positive association between urinary levels of phthalates and at least one semen parameter indicative of low semen quality; some studies also revealed sperm DNA damage. The studies on parabens less often revealed correlation of urinary parabens concentrations with a decrease in sperm count, as well as motility and DNA damage. Moreover, EDCs can elevate ROS production and lipid peroxidation, increase apoptosis, induce epigenetic modifications, and change the Y:X sperm chromosome ratio and sperm protein composition. Our review revealed detrimental effects of EDCs on semen quality and sperm DNA integrity-especially in BPA and phthalates, but also in parabens.
- Published
- 2022
- Full Text
- View/download PDF
30. Resonance and electrostatics making the difference in boron- and aluminum-halide structures and exchange reactivity.
- Author
-
Molina-Aguirre G, Pannell KH, and Pinter B
- Subjects
- Diamond, Halogens chemistry, Static Electricity, Aluminum, Boron chemistry
- Abstract
The mechanism of the gas-phase halogen-exchange reaction between boron- and aluminum-halides (i.e., BX
3 + BX3 and AlX3 + AlX3 , X = F, Cl, or Br) was discovered using density functional theory. The reaction takes place via a two-step mechanism with the intermediacy of a diamond-core structure analogous to diborane. Good agreement was found between the simulated reaction features and experimental observations, which demonstrate slow kinetics and an equilibrium process for boron species and dimer formation in the case of aluminum-halides. This computational and theoretical study also reveals and quantifies the effect of resonance on the thermodynamic stability of the central intermediate and conceptualizes the extreme stability difference (∼50 kcal mol-1 ) between boron and aluminum diamond-core bridge structures. Through an interaction energy decomposition analysis in combination with electronic structure analyses, we revealed that, beyond the resonance stabilization in free boron-halides, superior electrostatics in aluminum-halides results in the different reactivities, i.e., dimer formation for the latter species whereas substituent exchange for the former ones.- Published
- 2022
- Full Text
- View/download PDF
31. In Vitro, In Vivo and In Silico Characterization of a Novel Kappa-Opioid Receptor Antagonist.
- Author
-
Puls K, Olivé-Marti AL, Pach S, Pinter B, Erli F, Wolber G, and Spetea M
- Abstract
Kappa-opioid receptor (KOR) antagonists are promising innovative therapeutics for the treatment of the central nervous system (CNS) disorders. The new scaffold opioid ligand, Compound A, was originally found as a mu-opioid receptor (MOR) antagonist but its binding/selectivity and activation profile at the KOR and delta-opioid receptor (DOR) remain elusive. In this study, we present an in vitro, in vivo and in silico characterization of Compound A by revealing this ligand as a KOR antagonist in vitro and in vivo. In the radioligand competitive binding assay, Compound A bound at the human KOR, albeit with moderate affinity, but with increased affinity than to the human MOR and without specific binding at the human DOR, thus displaying a preferential KOR selectivity profile. Following subcutaneous administration in mice, Compound A effectively reverse the antinociceptive effects of the prototypical KOR agonist, U50,488. In silico investigations were carried out to assess the structural determinants responsible for opioid receptor subtype selectivity of Compound A. Molecular docking, molecular dynamics simulations and dynamic pharmacophore (dynophore) generation revealed differences in the stabilization of the chlorophenyl moiety of Compound A within the opioid receptor binding pockets, rationalizing the experimentally determined binding affinity values. This new chemotype bears the potential for favorable ADMET properties and holds promise for chemical optimization toward the development of potential therapeutics.
- Published
- 2022
- Full Text
- View/download PDF
32. Phosphorus and Arsenic Atom Transfer to Isocyanides to Form π-Backbonding Cyanophosphide and Cyanoarsenide Titanium Complexes.
- Author
-
Reinholdt A, Jafari MG, Sandoval-Pauker C, Ballestero-Martínez E, Gau MR, Driess M, Pinter B, and Mindiola DJ
- Abstract
Decarbonylation along with E atom transfer from Na(OCE) (E=P, As) to an isocyanide coordinated to the tetrahedral Ti
II complex [(TptBu,Me )TiCl], yielded the [(TptBu,Me )Ti(η3 -ECNAd)] species (Ad=1-adamantyl, TptBu,Me- =hydrotris(3-tert-butyl-5-methylpyrazol-1-yl)borate). In the case of E=P, the cyanophosphide ligand displays nucleophilic reactivity toward Al(CH3 )3 ; moreover, its bent geometry hints to a reduced Ad-NCP3- resonance contributor. The analogous and rarer mono-substituted cyanoarsenide ligand, Ad-NCAs3- , shows the same unprecedented coordination mode but with shortening of the N=C bond. As opposed to TiII , VII fails to promote P atom transfer to AdNC, yielding instead [(TptBu,Me )V(OCP)(CNAd)]. Theoretical studies revealed the rare ECNAd moieties to be stabilized by π-backbonding interactions with the former TiII ion, and their assembly to most likely involve a concerted E atom transfer between Ti-bound OCE- to AdNC ligands when studying the reaction coordinate for E=P., (© 2021 Wiley-VCH GmbH.)- Published
- 2021
- Full Text
- View/download PDF
33. Pursuit of an Electron Deficient Titanium Nitride.
- Author
-
Grant LN, Bhunia M, Pinter B, Rebreyend C, Carroll ME, Carroll PJ, de Bruin B, and Mindiola DJ
- Abstract
The nitride salt [(PN)
2 Ti≡N{μ2 -K(OEt2 )}]2 ( 1 ) (PN- = ( N -(2-Pi Pr2 -4-methylphenyl)-2,4,6-Me3 C6 H2 ) can be oxidized with two equiv of I2 or four equiv of ClCPh3 to produce the phosphinimide-halide complexes (NPN')(PN)Ti(X) (X- = I ( 2 ), Cl ( 3 ); NPN' = N-(2-NPi Pr2 -4-methylphenyl)-2,4,6-Me3 C6 H2 2- ), respectively. In the case of 2 , H2 was found to be one of the other products; whereas, HCPh3 and Gomberg's dimer were observed upon the formation of 3 . Independent studies suggest that the oxidation of 1 could imply the formation of the transient nitridyl species [(PN)2 Ti(≡N•)] ( A ), which can either oxidize the proximal phosphine atom to produce the Ti(III) intermediate [(NPN')(PN)Ti] ( B ) or, alternatively, engage in H atom abstraction to form the parent imido (PN)2 Ti≡NH ( 4 ). The latter was independently prepared and was found to photochemically convert to the titanium-hydride, (NPN')(PN)Ti(H) ( 5 ). Isotopic labeling studies using (PN)2 Ti≡ND ( 4 - d1 ) as well as reactivity studies of 5 with a hydride abstractor demonstrate the presence of the hydride ligand in 5 . An alternative route to putative A was observed via a photochemically promoted incomplete reduction of the azide ligand in (PN)2 Ti(N3 ) ( 6 ) to 4 . This process was accompanied by some formation of 5 . Frozen matrix X-band EPR studies of 6 , performed under photolytic conditions, were consistent with species B being formed under these reaction conditions, originating from a low barrier N-insertion into the phosphine group in the putative nitridyl species A . Computational studies were also undertaken to discover the mechanism and plausibility of the divergent pathways (via intermediates A and B ) in the formation of 2 and 3 , and to characterize the bonding and electronic structure of the elusive nitrogen-centered radical in A .- Published
- 2021
- Full Text
- View/download PDF
34. Vitamin D Supplementation During the COVID-19 Pandemic.
- Author
-
Siuka D, Pfeifer M, and Pinter B
- Subjects
- COVID-19, Coronavirus Infections epidemiology, Coronavirus Infections etiology, Global Health, Humans, Pneumonia, Viral epidemiology, Pneumonia, Viral etiology, Risk Factors, SARS-CoV-2, Vitamin D Deficiency complications, Betacoronavirus, Coronavirus Infections prevention & control, Dietary Supplements, Pandemics prevention & control, Pneumonia, Viral prevention & control, Vitamin D therapeutic use, Vitamin D Deficiency drug therapy, Vitamins therapeutic use
- Published
- 2020
- Full Text
- View/download PDF
35. Electron Density Difference Analysis on the Oxidative and Reductive Quenching Cycles of Classical Iridium and Ruthenium Photoredox Catalysts.
- Author
-
Medina E and Pinter B
- Abstract
In this study a detailed scrutiny of the electronic structure changes during the redox events of the oxidative and reductive quenching cycles of the representative homoleptic and heteroleptic octahedral iridium [Ir(bpy)
x (ppy)3- x ]x + ( x = 0, 1, 2, and 3) and ruthenium [Ru(bpy)x (ppy)3- x ]x -1+ ( x = 1, 2, and 3) photoredox catalysts is provided through the corresponding electron density difference Δρ( r ) distributions. The systematic analysis of the Δρ( r ) distributions provides intuitive insights into the details of the metal- and ligand-centered electron transfer processes that take place in the different excited- and ground-state redox steps of classical photoredox catalysis. In addition to the structural metrics, the measured ground-state reduction potentials were also reproduced with great accuracy, typically within 0.15 V, when using the TPSSh functional in combination with the Def2-TZVP basis set coupled to reparameterized implicit solvation model (SMD). We computed the excited-state reduction potentials of these ruthenium and iridium complexes without using TD-DFT, but by directly computing the solution-state Gibbs free energy of the triplet3 MLCT state, giving good agreement with respective experiments. The analyzed Δρ( r ) maps reveal the characteristic features of metal- and ligand-centered reductions and oxidations in both ground- and excited states and metal-to-ligand charge transfers (MLCT), sometimes perturbed by additional ligand-to-ligand charge transfer (LLCT) contributions. One of the most interesting features of ligand-centered redox processes is the localization of the accumulated electron density at one redox-active ligand in the case of heteroleptic systems [Ir(bpy)(ppy)2 ]+ and [Ru(bpy)(ppy)2 ]0 , which is in contrast to the delocalized nature of the ligands-hosted charge in homoleptic photoredox catalysts, such as the classical [Ru(bpy)3 ]2+ system.- Published
- 2020
- Full Text
- View/download PDF
36. Isolation of a Bimetallic Cobalt(III) Nitride and Examination of Its Hydrogen Atom Abstraction Chemistry and Reactivity toward H 2 .
- Author
-
Sengupta D, Sandoval-Pauker C, Schueller E, Encerrado-Manriquez AM, Metta-Magaña A, Lee WY, Seshadri R, Pinter B, and Fortier S
- Abstract
Room temperature photolysis of the bis(azide)cobaltate(II) complex [Na(THF)
x ][(ket guan)Co(N3 )2 ] (ket guan = [( t Bu2 CN)C(NDipp)2 ]- , Dipp = 2,6-diisopropylphenyl) ( 3a ) in THF cleanly forms the binuclear cobalt nitride Na(THF)4 {[(ket guan)Co(N3 )]2 (μ-N)} ( 1 ). Compound 1 represents the first example of an isolable, bimetallic cobalt nitride complex, and it has been fully characterized by spectroscopic, magnetic, and computational analyses. Density functional theory supports a CoIII ═N═CoIII canonical form with significant π-bonding between the cobalt centers and the nitride atom. Unlike other group 9 bridging nitride complexes, no radical character is detected at the bridging N atom of 1 . Indeed, 1 is unreactive toward weak C-H donors and even cocrystallizes with a molecule of cyclohexadiene (CHD) in its crystallographic unit cell to give 1 ·CHD as a room temperature stable product. Notably, addition of pyridine to 1 or photolyzed solutions of [(ket guan)Co(N3 )(py)]2 ( 4a ) leads to destabilization via activation of the nitride unit, resulting in the mixed-valent Co(II)/Co(III) bridged imido species [(ket guan)Co(py)][(ket guan)Co](μ-NH)(μ-N3 ) ( 5 ) formed from intermolecular hydrogen atom abstraction (HAA) of strong C-H bonds (BDE ∼ 100 kcal/mol). Kinetic rate analysis of the formation of 5 in the presence of C6 H12 or C6 D12 gives a KIE = 2.5 ± 0.1, supportive of a HAA formation pathway. The reactivity of our system was further probed by photolyzing benzene/pyridine solutions of 4a under H2 and D2 atmospheres (150 psi), which leads to the exclusive formation of the bis(imido) complexes [(ket guan)Co(μ-NH)]2 ( 6 ) and [(ket guan)Co(μ-ND)]2 ( 6-D ), respectively, as a result of dihydrogen activation. These results provide unique insights into the chemistry and electronic structure of late 3d metal nitrides while providing entryway into C-H activation pathways.- Published
- 2020
- Full Text
- View/download PDF
37. Pyridine Wingtip in [Pd(Py- tz NHC) 2 ] 2+ Complex Is a Proton Shuttle in the Catalytic Hydroamination of Alkynes.
- Author
-
Virant M, Mihelač M, Gazvoda M, Cotman AE, Frantar A, Pinter B, and Košmrlj J
- Abstract
The cationic palladium(II) complex 1 of pyridyl-mesoionic carbene ligand catalyzes Markovnikov-selective intermolecular hydroamination between anilines and terminal alkynes into the corresponding imines. The reaction proceeds at room temperature, in the absence of additives, with exquisite selectivity and diverse functional group tolerance. The key intrinsic feature of the catalyst is the pyridine wingtip confined to the proximity of the alkynophilic metal active site, which mimics the function of enzyme-like architectures by assisting entropically favored proton transfers.
- Published
- 2020
- Full Text
- View/download PDF
38. Reversible oxidative-addition and reductive-elimination of thiophene from a titanium complex and its thermally-induced hydrodesulphurization chemistry.
- Author
-
Gómez-Torres A, Aguilar-Calderón JR, Saucedo C, Jordan A, Metta-Magaña A, Pinter B, and Fortier S
- Abstract
The masked Ti(ii) synthon (Ketguan)(η6-ImDippN)Ti (1) oxidatively adds across thiophene to give ring-opened (Ketguan)(ImDippN)Ti[κ2-S(CH)3CH] (2). Complex 2 is photosensitive, and upon exposure to light, reductively eliminates thiophene to regenerate 1 - a rare example of early-metal mediated oxidative-addition/reductive-elimination chemistry. DFT calculations indicate strong titanium π-backdonation to the thiophene π*-orbitals leads to the observed thiophene ring opening across titanium, while a proposed photoinduced LMCT promotes the reverse thiophene elimination from 2. Finally, pressurizing solutions of 2 with H2 (150 psi) at 80 °C leads to the hydrodesulphurization of thiophene to give the Ti(iv) sulphide (Ketguan)(ImDippN)Ti(S) (3) and butane.
- Published
- 2020
- Full Text
- View/download PDF
39. Counselling before first trimester abortion and acceptability of the procedure: results from a Slovenian cross-sectional study.
- Author
-
Vodopivec S, Bokal EV, and Pinter B
- Subjects
- Abortifacient Agents administration & dosage, Abortifacient Agents adverse effects, Abortion, Induced psychology, Adult, Cross-Sectional Studies, Female, Hospitals, Public, Humans, Patient Participation, Patient Satisfaction, Pregnancy, Slovenia, Socioeconomic Factors, Abortion, Induced adverse effects, Abortion, Induced methods, Counseling methods, Decision Making, Pregnancy Trimester, First
- Abstract
Objectives: In Slovenia, first-trimester abortion is performed at the woman's request, either surgically under general anaesthesia or medically with mifepristone and misoprostol, in a public hospital. Our study aimed to evaluate pre-abortion counselling and to reveal differences in acceptability and satisfaction with the two abortion methods. Methods: A cross-sectional study was carried out at Ljubljana University Medical Centre between January and June 2015. Women requesting termination of a pregnancy up to 10 weeks' gestation voluntarily completed an anonymous questionnaire after the procedure and were divided into a surgical and a medical abortion group. Results: Of the 266 women who were invited to take part, 229 accepted; 16.6% chose a surgical abortion, 83.4% a medical abortion. The most frequent reason cited for requesting an abortion was economic/housing problems. Most women who chose a surgical abortion did so because it was faster, whereas most women who chose a medical abortion did so on the advice of a primary care gynaecologist. Women choosing a surgical abortion had more previous pregnancies and presented with a higher gestational age pregnancy. The choice of method was not related to the woman's age. There were no differences in acceptability of the two procedures. Pain during the procedure was, however, more severe in the medical abortion group ( p = .026), along with bleeding, nausea and chills; there were no differences in severity of vomiting, diarrhoea, dizziness or headache between the groups. Women in the surgical abortion group reported higher satisfaction with the method ( p < .001). The study revealed a low frequency of pre-abortion contraceptive counselling. Conclusion: The most common reason given for choosing a surgical abortion was the speed of the procedure; for a medical abortion, it was on the advice of a primary care gynaecologist. Satisfaction was higher with the surgical abortion method. There were no differences in general acceptability of the methods.
- Published
- 2019
- Full Text
- View/download PDF
40. Finding a soft spot for vanadium: a P-bound OCP ligand.
- Author
-
Grant LN, Krzystek J, Pinter B, Telser J, Grützmacher H, and Mindiola DJ
- Abstract
Transmetallation studies with the phosphaethynolate ion, [OCP]
- , have largely resulted in coordination according to classical Lewis acid-base theory. That is, for harder early transition metal ions, O-bound coordination has been observed, whereas in the case of softer late transition metal ions, P-bound coordination predominates. Herein, we report the use of a V(iii) complex, namely [(nacnac)VCl(OAr)] (1) (nacnac- = [ArNC(CH3 )]2 CH; Ar = 2,6-i Pr2 C6 H3 ), to transmetallate [OCP]- and bind via the P-atom as [(nacnac)V(OAr)(PCO)] (2), the first example of a 3d early transition metal that binds [OCP]- via the P-atom. Full characterization studies of this molecule including HFEPR spectroscopy, SQuID measurements, and theoretical studies are presented.- Published
- 2019
- Full Text
- View/download PDF
41. Molecular Zirconium Nitride Super Base from a Mononuclear Parent Imide.
- Author
-
Grant LN, Pinter B, Gu J, and Mindiola DJ
- Abstract
In this work, we prepared, isolated, and structurally characterized a zirconium complex having a terminally bound imide motif, (PN)
2 Zr≡NH (PN- = (N-(2-i Pr2 P-4-methylphenyl)-2,4,6-trimethylanilide)), along with the zirconium nitride complex {(PN)2 Zr≡N[μ2 -Li(THF)]}2 . (PN)2 Zr≡NH was prepared by reduction of trans-(PN)2 Zr(N3 )2 with KC8 . Isotopic labeling and spectroscopic studies were conducted using the respective15 N enriched isotopologues, whereas solid-state structural studies confirmed some of the shortest Zr≡N distances known to date (Zr≡NH, 1.830(3) Å; Zr≡N- , 1.822(2) Å). It was found that the nitride in {(PN)2 Zr≡N[μ2 -Li(THF)]}2 is super basic and in the range of -36 to -43 p Kb units. Computational studies have been applied to probe the bonding and structure for this new class of zirconium-nitrogen multiple bonds.- Published
- 2018
- Full Text
- View/download PDF
42. Mechanism of copper-free Sonogashira reaction operates through palladium-palladium transmetallation.
- Author
-
Gazvoda M, Virant M, Pinter B, and Košmrlj J
- Abstract
The seminal contributions by Sonogashira, Cassar and Heck in mid 1970s on Pd/Cu- and Pd-catalysed (copper-free) coupling of acetylenes with aryl or vinyl halides have evolved in myriad applications. Despite the enormous success both in academia and in industry, however, critical mechanistic questions of this cross-coupling process remain unresolved. In this study, experimental evidence and computational support is provided for the mechanism of copper-free Sonogashira cross-coupling reaction. In contrast to the consensus monometallic mechanism, the revealed pathway proceeds through a tandem Pd/Pd cycle linked via a multistep transmetallation process. This cycle is virtually identical to the Pd/Cu tandem mechanism of copper co-catalysed Sonogashira cross-couplings, but the role of Cu
I is played by a set of PdII species. Phosphine dissociation from the square-planar reactants to form transient three-coordinate Pd species initiates transmetallation and represents the rate-determining step of the process.- Published
- 2018
- Full Text
- View/download PDF
43. Relationship between the MDS-UPDRS and Quality of Life: A large multicenter study of 3206 patients.
- Author
-
Skorvanek M, Martinez-Martin P, Kovacs N, Zezula I, Rodriguez-Violante M, Corvol JC, Taba P, Seppi K, Levin O, Schrag A, Aviles-Olmos I, Alvarez-Sanchez M, Arakaki T, Aschermann Z, Benchetrit E, Benoit C, Bergareche-Yarza A, Cervantes-Arriaga A, Chade A, Cormier F, Datieva V, Gallagher DA, Garretto N, Gdovinova Z, Gershanik O, Grofik M, Han V, Kadastik-Eerme L, Kurtis MM, Mangone G, Martinez-Castrillo JC, Mendoza-Rodriguez A, Minar M, Moore HP, Muldmaa M, Mueller C, Pinter B, Poewe W, Rallmann K, Reiter E, Rodriguez-Blazquez C, Singer C, Valkovic P, Goetz CG, and Stebbins GT
- Subjects
- Aged, Cross-Sectional Studies, Female, Humans, Male, Middle Aged, Regression Analysis, Parkinson Disease diagnosis, Psychiatric Status Rating Scales, Quality of Life, Severity of Illness Index
- Abstract
Background: The relationship between Health-Related Quality of Life (HRQoL) and MDS-UPDRS has not been fully studied so far. The aim of this study was to evaluate the relationship between all MDS-UPDRS components and HRQoL in a representative international cohort of PD patients., Methods: We collected demographic and disease-related data as well as MDS-UPDRS and PDQ8 scales. Data were analyzed using correlations between PDQ8 and all MDS-UPDRS items, subsequently two hierarchical multiple regressions were performed, first between the scores of the MDS-UPDRS Parts and PDQ8 and second between individual items from those Parts demonstrating significant relationship to PDQ8 scores in the first regression. LASSO regression analyses were performed to evaluate the relationship between PDQ8 and all individual MDS-UPDRS items., Results: A total of 3206 PD patients were included in the study. In the first regression analysis, PDQ8 was significantly related to MDS-UPDRS parts I and II, but not to III and IV. In the second regression model, significant contributions to PDQ8 were found for Part I items Fatigue, Pain, Depressed mood, Apathy; and Part II items Dressing, Doing hobbies, Freezing, Speech and Tremor. In the LASSO analysis, six Part I, seven Part II, three Part III and one Part IV items contributed to PDQ8 scores. The five items most significantly related to the model were Depressed mood, Dressing, Apathy, Pain and Fatigue., Conclusions: This is so far the largest study related to HRQoL issues in PD. Restrictions in activities of daily living and non-motor symptoms significantly contribute to HRQoL in PD., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
44. Characterization of chalcogen bonding interactions via an in-depth conceptual quantum chemical analysis.
- Author
-
De Vleeschouwer F, Denayer M, Pinter B, Geerlings P, and De Proft F
- Abstract
The chalcogen bond has been acknowledged as an influential noncovalent interaction (NCI) between an electron-deficient chalcogen (donor) and a Lewis base (acceptor). This work explores the main features of chalcogen bonding through a large-scale computational study on a series of donors and acceptors spanning a wide range in strength and character of this type of bond: (benzo)chalcogenadiazoles (with Ch = Te/Se/S) versus halides and neutral Lewis bases with O, N, and C as donor atoms. We start from Pearson's hard and soft acids and bases (HSAB) principle, where the hard nature of the chalcogen bond is quantified through the molecular electrostatic potential and the soft nature through the Fukui function. The σ-holes are more pronounced when going down in the periodic table and their directionality matches the structural orientation of donors and acceptors in the complexes. The Fukui functions point toward an n→σ*-type interaction. The initial conjectures are further scrutinized using quantum mechanical methods, mostly relating to the systems' electron density. A Ziegler-Rauk energy decomposition analysis shows that electrostatics plays a distinctly larger role for the soft halides than for the hard, uncharged acceptors, associated with the softness matching within the HSAB principle. The natural orbital for chemical valence analysis confirms the n→σ* electron donation mechanism. Finally, the electron density and local density energy at the bond critical point in the quantum theory of atoms in molecules study and the position of the spikes in the reduced density gradient versus density plot in the NCI theory situate the chalcogen bond in the same range as strong hydrogen bonds. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)
- Published
- 2018
- Full Text
- View/download PDF
45. Conceptual Insights into DFT Spin-State Energetics of Octahedral Transition-Metal Complexes through a Density Difference Analysis.
- Author
-
Pinter B, Chankisjijev A, Geerlings P, Harvey JN, and De Proft F
- Abstract
In this study, an intuitive concept is derived, which explains the characteristic dependence of spin-state energetics on the exact exchange admixture of DFT functionals in the case of octahedral transition metal complexes. The change in electron density distributions upon varying the admixture, c
3 , in the B3LYP functional is analyzed for archetype ionic and covalent systems as well as for the Fe2+ ion in an ideal octahedral field. An understanding of how the DFT description of the electronic structure of octahedral complexes changes as a function of c3 is sought. A systematic spin-state energy analysis of 50 octahedral complexes of various metals and ligands with consistent experimental data is presented, allowing the derivation, in theory, of an optimal c3 value for each system. The notion that the admixture dependence of DFT spin-state energetics stems from the treatment of nondynamic electrons arising from the mixing of (M-Lz2 )0 (dz2 )2 and (M-Lx2-y2 )0 (dx2-y2 )2 configurations into the dominant (M-Lx2-y2 )2 (dx2-y2 )0 and (M-Lx2-y2 )2 (dx2-y2 )0 ones in the low(er) spin states is put forward. That is, in the effort to mimic such electron-electron interactions, Ex LDA overestimates, whereas exact exchange downplays the contribution of this type of electron correlation to the stability of low(er) spin states, leading to the widespread practical observation that the higher the exact exchange admixture, the more stable the high-spin-state configuration., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2018
- Full Text
- View/download PDF
46. A Scandium-Stabilized Diisophosphaethynolate Ligand: [OCPPCO] 4 .
- Author
-
Grant LN, Pinter B, Manor BC, Grützmacher H, and Mindiola DJ
- Abstract
The first example of the OCPPCO ligand, diisophosphaethynolate, is reported via reductive coupling of a Sc-OCP precursor. Upon reduction with KC
8 , isolation of the dinuclear complex, namely [K(OEt2 )]2 [(nacnac)Sc(OAr)]2 (OCPPCO), is observed, leading to a unique motif [OCPPCO]4- , stabilized by two scandium centers. Detailed NMR spectra of all complexes as well as IR and single crystal X-ray studies were obtained to fully elucidate the nature of these complexes in solution as well as in the solid state. Theory is combined to probe the electronic structure and orbitals responsible for the bonding interactions in the Sc-OCPPCO-Sc skeleton but also to compare to the linear mode observed in the precursor., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2018
- Full Text
- View/download PDF
47. Heterolytic Splitting of Molecular Hydrogen by Frustrated and Classical Lewis Pairs: A Unified Reactivity Concept.
- Author
-
Skara G, De Vleeschouwer F, Geerlings P, De Proft F, and Pinter B
- Abstract
Using a set of state-of-the-art quantum chemical techniques we scrutinized the characteristically different reactivity of frustrated and classical Lewis pairs towards molecular hydrogen. The mechanisms and reaction profiles computed for the H
2 splitting reaction of various Lewis pairs are in good agreement with the experimentally observed feasibility of H2 activation. More importantly, the analysis of activation parameters unambiguously revealed the existence of two reaction pathways through a low-energy and a high-energy transition state. An exhaustive scrutiny of these transition states, including their stability, geometry and electronic structure, reflects that the electronic rearrangement in low-energy transition states is fundamentally different from that of high-energy transition states. Our findings reveal that the widespread consensus mechanism of H2 splitting characterizes activation processes corresponding to high-energy transition states and, accordingly, is not operative for H2 -activating systems. One of the criteria of H2 -activation, actually, is the availability of a low-energy transition state that represents a different H2 splitting mechanism, in which the electrostatic field generated in the cavity of Lewis pair plays a critical role: to induce a strong polarization of H2 that facilities an efficient end-on acid-H2 interaction and to stabilize the charge separated "H+ -H- " moiety in the transition state.- Published
- 2017
- Full Text
- View/download PDF
48. A Terminal Iron(IV) Nitride Supported by a Super Bulky Guanidinate Ligand and Examination of Its Electronic Structure and Reactivity.
- Author
-
Maity AK, Murillo J, Metta-Magaña AJ, Pinter B, and Fortier S
- Abstract
Utilizing the bulky guanidinate ligand [L
Ar* ]- (LAr* = (Ar*N)2 C(R), Ar* = 2,6-bis(diphenylmethyl)-4-tert-butylphenyl, R = NCt Bu2 ) for kinetic stabilization, the synthesis of a rare terminal Fe(IV) nitride complex is reported. UV irradiation of a pyridine solution of the Fe(II) azide [LAr* ]FeN3 (py) (3-py) at 0 °C cleanly generates the Fe(IV) nitride [LAr* ]FeN(py) (1). The15 N NMR spectrum of the 115 N15 N) isotopomer shows a resonance at 1016 ppm (vs externally referenced CH3 NO2 at 380 ppm), comparable to that known for other terminal iron nitrides. Notably, the computed structure of 1 reveals an iron center with distorted tetrahedral geometry, τ4 = 0.72, featuring a short Fe≡N bond (1.52 Å). Inspection of the frontier orbital ordering of 1 shows a relatively small HOMO/LUMO gap with the LUMO comprised by Fe(dxz,yz )N(px,y ) π*-orbitals, a splitting that is manifested in the electronic absorption spectrum of 1 (λ = 610 nm, ε = 1375 L·mol-1 ·cm-1 ; λ = 613 nm (calcd)). Complex 1 persists in low-temperature solutions of pyridine but becomes unstable at room temperature, gradually converting to the Fe(II) hydrazide product [κ2 -(t Bu2 CN)C(η6 -NAr*)(N-NAr*)]Fe (4) upon standing via intramolecular N-atom insertion. This reactivity of the Fe≡N moiety was assessed through molecular orbital analysis, which suggests electrophilic character at the nitride functionality. Accordingly, treatment of 1 with the nucleophiles PMe2 Ph and Ar-N≡C (Ar = 2,6-dimethylphenyl) leads to partial N-atom transfer and formation of the Fe(II) addition products [LAr* ]Fe(N═PMe2 Ph)(py) (5) and [LAr* ]Fe(N═C═NAr)(py) (6). Similarly, 1 reacts with PhSiH3 to give [LAr* ]Fe[N(H)(SiH2 Ph)](py) (7) which Fukui analysis shows to proceed via electrophilic insertion of the nitride into the Si-H bond.- Published
- 2017
- Full Text
- View/download PDF
49. A Planar Ti 2 P 2 Core Assembled by Reductive Decarbonylation of - O-C≡P and P-P Radical Coupling.
- Author
-
Grant LN, Pinter B, Manor BC, Suter R, Grützmacher H, and Mindiola DJ
- Abstract
The complex [(nacnac)Ti(OAr)]
2 (μ2 :η2 ,η2 -P2 ) (1) is formed via reductive decarbonylation of the phosphaethynolate ion- [OCP], which serves as a P atom source. Complex 1 is the first structurally characterized Group 4 transition metal P2 complex and its structure reveals the rhombic Ti2 P2 core is essentially planar with short bond lengths suggesting some degree of multiple bonding character between the Ti-P and P-P sites. Computational studies of 1 provide an understanding of the Ti2 P2 core as well as the origin of the highly downfield31 P NMR spectroscopic signal., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2017
- Full Text
- View/download PDF
50. Differences in MDS-UPDRS Scores Based on Hoehn and Yahr Stage and Disease Duration.
- Author
-
Skorvanek M, Martinez-Martin P, Kovacs N, Rodriguez-Violante M, Corvol JC, Taba P, Seppi K, Levin O, Schrag A, Foltynie T, Alvarez-Sanchez M, Arakaki T, Aschermann Z, Aviles-Olmos I, Benchetrit E, Benoit C, Bergareche-Yarza A, Cervantes-Arriaga A, Chade A, Cormier F, Datieva V, Gallagher DA, Garretto N, Gdovinova Z, Gershanik O, Grofik M, Han V, Huang J, Kadastik-Eerme L, Kurtis MM, Mangone G, Martinez-Castrillo JC, Mendoza-Rodriguez A, Minar M, Moore HP, Muldmaa M, Mueller C, Pinter B, Poewe W, Rallmann K, Reiter E, Rodriguez-Blazquez C, Singer C, Tilley BC, Valkovic P, Goetz CG, and Stebbins GT
- Abstract
Background: The Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) is a newly developed tool to assess Parkinson's disease (PD). Changes in scores on the scale over the course of PD, including increasing disease duration and Hoehn and Yahr (HY) stages, have not been described. The objectives of this study were to analyze MDS-UPDRS scores on Parts I through IV and their differences based on HY stage and disease duration in a large cohort of patients with PD., Methods: For this cross-sectional study, demographic data and MDS-UPDRS scores were collected, including HY stage. Subscores on MDS-UPDRS Parts I through IV were analyzed using 1-way analyses of variance for each HY stage and in 5-year increments of disease duration. Part III (motor assessment) scores were analyzed separately for on and off states., Results: The mean age of the 3206 patients was 65.8 ± 10.6 years, 53.3% were men, the mean disease duration was 11.5 ± 4.6 years, and the median HY stage was 2 (range, 0-5); 2156 patients were examined in an on state and 987 were examined in an off state. Scores for all MDS-UPDRS parts increased significantly through HY stages 1 through 5, with an average increase of 3.8, 7.7, 14.6, and 2.0 points consecutively for parts I through IV, respectively. For the 5-year increments of disease duration, MDS-UPDRS subscores increased by an average of 1.6, 3.3, 4.2, and 1.4 points consecutively for parts I through IV, respectively. This increase was significant only during the first 15 years of disease for all 4 parts, including part III scores evaluated in both on and off states., Conclusions: MDS-UPDRS scores for all 4 parts increase significantly with every HY stage and also with 5-year increments of disease duration in the first 15 years of the disease.
- Published
- 2017
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.