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42 results on '"G. Vashchenko"'

1. Budgeting the emittance of photoemitted electron beams in a space-charge affected emission regime for free-electron laser applications

Author

Y. Chen, M. Krasilnikov, M. Gross, P. Huang, I. Isaev, C. Koschitzki, X.-K. Li, O. Lishilin, G. Loisch, R. Niemczyk, A. Oppelt, H.-J. Qian, G. Shu, F. Stephan, and G. Vashchenko

Subjects
Physics, QC1-999
Abstract

Free-electron laser based x-ray facilities require high-brightness photoinjectors to provide low emittance electron beams at a fixed bunch charge. The emittance optimization in the injector determines the lowest achievable emittance. Based on experimental emittance optimization at the photoinjector test facility at DESY in Zeuthen, a space-charge affected emission regime is identified, in which the optimum transverse beam emittance is achieved and thus, the injector is routinely operated in this regime. An advanced modeling approach is proposed to consider a dynamic emission process in the simulation of injector beam dynamics, meanwhile allowing detailed studies of the impact of strong space-charge fields during emission on the slice formation of the emitted electron bunch at the cathode. As an application, the proposed approach is used to analyze the budget of the optimized transverse beam emittance. An interplay, taking place in the identified emission regime, between intrinsic cathode emittance and space-charge induced emittance is demonstrated. The resolved behavior by simulation is consistent with the corresponding measurement under practical operation conditions of interest. The obtained results are reported.

Published
2020
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2. Experimentally minimized beam emittance from an L-band photoinjector

Author

M. Krasilnikov, F. Stephan, G. Asova, H.-J. Grabosch, M. Groß, L. Hakobyan, I. Isaev, Y. Ivanisenko, L. Jachmann, M. Khojoyan, G. Klemz, W. Köhler, M. Mahgoub, D. Malyutin, M. Nozdrin, A. Oppelt, M. Otevrel, B. Petrosyan, S. Rimjaem, A. Shapovalov, G. Vashchenko, S. Weidinger, R. Wenndorff, K. Flöttmann, M. Hoffmann, S. Lederer, H. Schlarb, S. Schreiber, I. Templin, I. Will, V. Paramonov, and D. Richter

Subjects
Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

High brightness electron sources for linac based free-electron lasers (FELs) are being developed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). Production of electron bunches with extremely small transverse emittance is the focus of the PITZ scientific program. The photoinjector optimization in 2008–2009 for a bunch charge of 1, 0.5, 0.25, and 0.1 nC resulted in measured emittance values which are beyond the requirements of the European XFEL [S. Rimjaem et al., Nucl. Instrum. Methods Phys. Res., Sect. A 671, 62 (2012)NIMAER0168-900210.1016/j.nima.2011.12.101]. Several essential modifications were commissioned in 2010–2011 at PITZ, resulting in further improvement of the photoinjector performance. Significant improvement of the rf gun phase stability is a major contribution in the reduction of the measured transverse emittance. The old TESLA prototype booster was replaced by a new cut disk structure cavity. This allows acceleration of the electron beam to higher energies and supports much higher flexibility for stable booster operation as well as for longer rf pulses which is of vital importance especially for the emittance optimization of low charge bunches. The transverse phase space of the electron beam was optimized at PITZ for bunch charges in the range between 0.02 and 2 nC, where the quality of the beam measurements was preserved by utilizing long pulse train operation. The experimental optimization yielded worldwide unprecedented low normalized emittance beams in the whole charge range studied.

Published
2012
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3. The effect of seed size, method of seed calibration and seeding date on the depth of bedding of the tillering node of winter wheat plants in the conditions of the Central Chernozem Region

Author

Technologies named after G.F. Morozov, Tatiana G. Vashchenko, Alexandr Golev, Galina G. Goleva, and Veronika Pushkareva

Subjects
Agronomy, Bedding, Calibration (statistics), Node (networking), Winter wheat, General Engineering, General Earth and Planetary Sciences, Environmental science, Seeding, Chernozem, General Environmental Science
Published
2020
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5. THE TECHNOLOGY OF CREATING RESTITUTION SUGAR BEET LINES

Author

Elena N. Vasilchenko, Tatiana P. Zhuzhzhalova, Sugar, Tatiana G. Vashchenko, and Elena O. Kolesnikova

Subjects
0106 biological sciences, Restitution, biology, Agronomy, 010604 marine biology & hydrobiology, Sugar beet, Business, biology.organism_classification, 01 natural sciences, 010606 plant biology & botany
Published
2018
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9. MORPHO-BIOLOGICAL DIVERSITY OF WINTER WHEAT VARIETIES ASSESSMENT

Author

Galina G. Goleva, Tatiana G. Vashchenko

Subjects
Hybrids genotypes, Winter wheat, Selection of parent components for crosses, Cluster analysis, Wheat hybridization, Morpho-biological indicators, Discriminant analysis, Breeding samples
Abstract

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies, 11, 10, 11A10B: 1-10

Published
2020
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10. A MHz-Repetition-Rate Hard X-Ray Free-Electron Laser Driven by a Superconducting Linear Accelerator

Author

W. Decking, S. Abeghyan, P. Abramian, A. Abramsky, A. Aguirre, C. Albrecht, P. Alou, M. Altarelli, P. Altmann, K. Amyan, V. Anashin, E. Apostolov, K. Appel, D. Auguste, V. Ayvazyan, S. Baark, F. Babies, N. Baboi, P. Bak, V. Balandin, R. Baldinger, B. Baranasic, S. Barbanotti, O. Belikov, V. Belokurov, L. Belova, V. Belyakov, S. Berry, M. Bertucci, B. Beutner, A. Block, M. Blöcher, T. Böckmann, C. Bohm, M. Böhnert, V. Bondar, E. Bondarchuk, M. Bonezzi, P. Borowiec, C. Bösch, U. Bösenberg, A. Bosotti, R. Böspflug, M. Bousonville, E. Boyd, Y. Bozhko, A. Brand, J. Branlard, S. Briechle, F. Brinker, S. Brinker, R. Brinkmann, S. Brockhauser, O. Brovko, H. Brück, A. Brüdgam, L. Butkowski, T. Büttner, J. Calero, E. Castro-Carballo, G. Cattalanotto, J. Charrier, J. Chen, A. Cherepenko, V. Cheskidov, M. Chiodini, A. Chong, S. Choroba, M. Chorowski, D. Churanov, W. Cichalewski, M. Clausen, W. Clement, C. Cloué, J. A. Cobos, N. Coppola, S. Cunis, K. Czuba, M. Czwalinna, B. D’Almagne, J. Dammann, H. Danared, A. de Zubiaurre Wagner, A. Delfs, T. Delfs, F. Dietrich, T. Dietrich, M. Dohlus, M. Dommach, A. Donat, X. Dong, N. Doynikov, M. Dressel, M. Duda, P. Duda, H. Eckoldt, W. Ehsan, J. Eidam, F. Eints, C. Engling, U. Englisch, A. Ermakov, K. Escherich, J. Eschke, E. Saldin, M. Faesing, A. Fallou, M. Felber, M. Fenner, B. Fernandes, J. M. Fernández, S. Feuker, K. Filippakopoulos, K. Floettmann, V. Fogel, M. Fontaine, A. Francés, I. Freijo Martin, W. Freund, T. Freyermuth, M. Friedland, L. Fröhlich, M. Fusetti, J. Fydrych, A. Gallas, O. García, L. Garcia-Tabares, G. Geloni, N. Gerasimova, C. Gerth, P. Geßler, V. Gharibyan, M. Gloor, J. Głowinkowski, A. Goessel, Z. Gołębiewski, N. Golubeva, W. Grabowski, W. Graeff, A. Grebentsov, M. Grecki, T. Grevsmuehl, M. Gross, U. Grosse-Wortmann, J. Grünert, S. Grunewald, P. Grzegory, G. Feng, H. Guler, G. Gusev, J. L. Gutierrez, L. Hagge, M. Hamberg, R. Hanneken, E. Harms, I. Hartl, A. Hauberg, S. Hauf, J. Hauschildt, J. Hauser, J. Havlicek, A. Hedqvist, N. Heidbrook, F. Hellberg, D. Henning, O. Hensler, T. Hermann, A. Hidvégi, M. Hierholzer, H. Hintz, F. Hoffmann, Markus Hoffmann, Matthias Hoffmann, Y. Holler, M. Hüning, A. Ignatenko, M. Ilchen, A. Iluk, J. Iversen, M. Izquierdo, L. Jachmann, N. Jardon, U. Jastrow, K. Jensch, J. Jensen, M. Jeżabek, M. Jidda, H. Jin, N. Johansson, R. Jonas, W. Kaabi, D. Kaefer, R. Kammering, H. Kapitza, S. Karabekyan, S. Karstensen, K. Kasprzak, V. Katalev, D. Keese, B. Keil, M. Kholopov, M. Killenberger, B. Kitaev, Y. Klimchenko, R. Klos, L. Knebel, A. Koch, M. Koepke, S. Köhler, W. Köhler, N. Kohlstrunk, Z. Konopkova, A. Konstantinov, W. Kook, W. Koprek, M. Körfer, O. Korth, A. Kosarev, K. Kosiński, D. Kostin, Y. Kot, A. Kotarba, T. Kozak, V. Kozak, R. Kramert, M. Krasilnikov, A. Krasnov, B. Krause, L. Kravchuk, O. Krebs, R. Kretschmer, J. Kreutzkamp, O. Kröplin, K. Krzysik, G. Kube, H. Kuehn, N. Kujala, V. Kulikov, V. Kuzminych, D. La Civita, M. Lacroix, T. Lamb, A. Lancetov, M. Larsson, D. Le Pinvidic, S. Lederer, T. Lensch, D. Lenz, A. Leuschner, F. Levenhagen, Y. Li, J. Liebing, L. Lilje, T. Limberg, D. Lipka, B. List, J. Liu, S. Liu, B. Lorbeer, J. Lorkiewicz, H. H. Lu, F. Ludwig, K. Machau, W. Maciocha, C. Madec, C. Magueur, C. Maiano, I. Maksimova, K. Malcher, T. Maltezopoulos, E. Mamoshkina, B. Manschwetus, F. Marcellini, G. Marinkovic, T. Martinez, H. Martirosyan, W. Maschmann, M. Maslov, A. Matheisen, U. Mavric, J. Meißner, K. Meissner, M. Messerschmidt, N. Meyners, G. Michalski, P. Michelato, N. Mildner, M. Moe, F. Moglia, C. Mohr, S. Mohr, W. Möller, M. Mommerz, L. Monaco, C. Montiel, M. Moretti, I. Morozov, P. Morozov, D. Mross, J. Mueller, C. Müller, J. Müller, K. Müller, J. Munilla, A. Münnich, V. Muratov, O. Napoly, B. Näser, N. Nefedov, Reinhard Neumann, Rudolf Neumann, N. Ngada, D. Noelle, F. Obier, I. Okunev, J. A. Oliver, M. Omet, A. Oppelt, A. Ottmar, M. Oublaid, C. Pagani, R. Paparella, V. Paramonov, C. Peitzmann, J. Penning, A. Perus, F. Peters, B. Petersen, A. Petrov, I. Petrov, S. Pfeiffer, J. Pflüger, S. Philipp, Y. Pienaud, P. Pierini, S. Pivovarov, M. Planas, E. Pławski, M. Pohl, J. Polinski, V. Popov, S. Prat, J. Prenting, G. Priebe, H. Pryschelski, K. Przygoda, E. Pyata, B. Racky, A. Rathjen, W. Ratuschni, S. Regnaud-Campderros, K. Rehlich, D. Reschke, C. Robson, J. Roever, M. Roggli, J. Rothenburg, E. Rusiński, R. Rybaniec, H. Sahling, M. Salmani, L. Samoylova, D. Sanzone, F. Saretzki, O. Sawlanski, J. Schaffran, H. Schlarb, M. Schlösser, V. Schlott, C. Schmidt, F. Schmidt-Foehre, M. Schmitz, M. Schmökel, T. Schnautz, E. Schneidmiller, M. Scholz, B. Schöneburg, J. Schultze, C. Schulz, A. Schwarz, J. Sekutowicz, D. Sellmann, E. Semenov, S. Serkez, D. Sertore, N. Shehzad, P. Shemarykin, L. Shi, M. Sienkiewicz, D. Sikora, M. Sikorski, A. Silenzi, C. Simon, W. Singer, X. Singer, H. Sinn, K. Sinram, N. Skvorodnev, P. Smirnow, T. Sommer, A. Sorokin, M. Stadler, M. Steckel, B. Steffen, N. Steinhau-Kühl, F. Stephan, M. Stodulski, M. Stolper, A. Sulimov, R. Susen, J. Świerblewski, C. Sydlo, E. Syresin, V. Sytchev, J. Szuba, N. Tesch, J. Thie, A. Thiebault, K. Tiedtke, D. Tischhauser, J. Tolkiehn, S. Tomin, F. Tonisch, F. Toral, I. Torbin, A. Trapp, D. Treyer, G. Trowitzsch, T. Trublet, T. Tschentscher, F. Ullrich, M. Vannoni, P. Varela, G. Varghese, G. Vashchenko, M. Vasic, C. Vazquez-Velez, A. Verguet, S. Vilcins-Czvitkovits, R. Villanueva, B. Visentin, M. Viti, E. Vogel, E. Volobuev, R. Wagner, N. Walker, T. Wamsat, H. Weddig, G. Weichert, H. Weise, R. Wenndorf, M. Werner, R. Wichmann, C. Wiebers, M. Wiencek, T. Wilksen, I. Will, L. Winkelmann, M. Winkowski, K. Wittenburg, A. Witzig, P. Wlk, T. Wohlenberg, M. Wojciechowski, F. Wolff-Fabris, G. Wrochna, K. Wrona, M. Yakopov, B. Yang, F. Yang, M. Yurkov, I. Zagorodnov, P. Zalden, A. Zavadtsev, D. Zavadtsev, A. Zhirnov, A. Zhukov, V. Ziemann, A. Zolotov, N. Zolotukhina, F. Zummack, D. Zybin, Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph], Astrophysics::High Energy Astrophysical Phenomena, 02 engineering and technology, 7. Clean energy, 01 natural sciences, Acceleration voltage, Linear particle accelerator, law.invention, 010309 optics, Optics, law, 0103 physical sciences, ddc:530, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Physics, business.industry, Free-electron laser, Undulator, 021001 nanoscience & nanotechnology, Laser, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Cathode ray, Physics::Accelerator Physics, 0210 nano-technology, business, Lasing threshold, Beam (structure)
Abstract

Nature photonics 14(6), 391 - 397 (2020). doi:10.1038/s41566-020-0607-z, The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created., Published by Nature Publ. Group, London [u.a.]

Published
2020
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14. Author Correction: A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator

Author

W. Decking, S. Abeghyan, P. Abramian, A. Abramsky, A. Aguirre, C. Albrecht, P. Alou, M. Altarelli, P. Altmann, K. Amyan, V. Anashin, E. Apostolov, K. Appel, D. Auguste, V. Ayvazyan, S. Baark, F. Babies, N. Baboi, P. Bak, V. Balandin, R. Baldinger, B. Baranasic, S. Barbanotti, O. Belikov, V. Belokurov, L. Belova, V. Belyakov, S. Berry, M. Bertucci, B. Beutner, A. Block, M. Blöcher, T. Böckmann, C. Bohm, M. Böhnert, V. Bondar, E. Bondarchuk, M. Bonezzi, P. Borowiec, C. Bösch, U. Bösenberg, A. Bosotti, R. Böspflug, M. Bousonville, E. Boyd, Y. Bozhko, A. Brand, J. Branlard, S. Briechle, F. Brinker, S. Brinker, R. Brinkmann, S. Brockhauser, O. Brovko, H. Brück, A. Brüdgam, L. Butkowski, T. Büttner, J. Calero, E. Castro-Carballo, G. Cattalanotto, J. Charrier, J. Chen, A. Cherepenko, V. Cheskidov, M. Chiodini, A. Chong, S. Choroba, M. Chorowski, D. Churanov, W. Cichalewski, M. Clausen, W. Clement, C. Cloué, J. A. Cobos, N. Coppola, S. Cunis, K. Czuba, M. Czwalinna, B. D’Almagne, J. Dammann, H. Danared, A. de Zubiaurre Wagner, A. Delfs, T. Delfs, F. Dietrich, T. Dietrich, M. Dohlus, M. Dommach, A. Donat, X. Dong, N. Doynikov, M. Dressel, M. Duda, P. Duda, H. Eckoldt, W. Ehsan, J. Eidam, F. Eints, C. Engling, U. Englisch, A. Ermakov, K. Escherich, J. Eschke, E. Saldin, M. Faesing, A. Fallou, M. Felber, M. Fenner, B. Fernandes, J. M. Fernández, S. Feuker, K. Filippakopoulos, K. Floettmann, V. Fogel, M. Fontaine, A. Francés, I. Freijo Martin, W. Freund, T. Freyermuth, M. Friedland, L. Fröhlich, M. Fusetti, J. Fydrych, A. Gallas, O. García, L. Garcia-Tabares, G. Geloni, N. Gerasimova, C. Gerth, P. Geßler, V. Gharibyan, M. Gloor, J. Głowinkowski, A. Goessel, Z. Gołębiewski, N. Golubeva, W. Grabowski, W. Graeff, A. Grebentsov, M. Grecki, T. Grevsmuehl, M. Gross, U. Grosse-Wortmann, J. Grünert, S. Grunewald, P. Grzegory, G. Feng, H. Guler, G. Gusev, J. L. Gutierrez, L. Hagge, M. Hamberg, R. Hanneken, E. Harms, I. Hartl, A. Hauberg, S. Hauf, J. Hauschildt, J. Hauser, J. Havlicek, A. Hedqvist, N. Heidbrook, F. Hellberg, D. Henning, O. Hensler, T. Hermann, A. Hidvégi, M. Hierholzer, H. Hintz, F. Hoffmann, Markus Hoffmann, Matthias Hoffmann, Y. Holler, M. Hüning, A. Ignatenko, M. Ilchen, A. Iluk, J. Iversen, M. Izquierdo, L. Jachmann, N. Jardon, U. Jastrow, K. Jensch, J. Jensen, M. Jeżabek, M. Jidda, H. Jin, N. Johansson, R. Jonas, W. Kaabi, D. Kaefer, R. Kammering, H. Kapitza, S. Karabekyan, S. Karstensen, K. Kasprzak, V. Katalev, D. Keese, B. Keil, M. Kholopov, M. Killenberger, B. Kitaev, Y. Klimchenko, R. Klos, L. Knebel, A. Koch, M. Koepke, S. Köhler, W. Köhler, N. Kohlstrunk, Z. Konopkova, A. Konstantinov, W. Kook, W. Koprek, M. Körfer, O. Korth, A. Kosarev, K. Kosiński, D. Kostin, Y. Kot, A. Kotarba, T. Kozak, V. Kozak, R. Kramert, M. Krasilnikov, A. Krasnov, B. Krause, L. Kravchuk, O. Krebs, R. Kretschmer, J. Kreutzkamp, O. Kröplin, K. Krzysik, G. Kube, H. Kuehn, N. Kujala, V. Kulikov, V. Kuzminych, D. La Civita, M. Lacroix, T. Lamb, A. Lancetov, M. Larsson, D. Le Pinvidic, S. Lederer, T. Lensch, D. Lenz, A. Leuschner, F. Levenhagen, Y. Li, J. Liebing, L. Lilje, T. Limberg, D. Lipka, B. List, J. Liu, S. Liu, B. Lorbeer, J. Lorkiewicz, H. H. Lu, F. Ludwig, K. Machau, W. Maciocha, C. Madec, C. Magueur, C. Maiano, I. Maksimova, K. Malcher, T. Maltezopoulos, E. Mamoshkina, B. Manschwetus, F. Marcellini, G. Marinkovic, T. Martinez, H. Martirosyan, W. Maschmann, M. Maslov, A. Matheisen, U. Mavric, J. Meißner, K. Meissner, M. Messerschmidt, N. Meyners, G. Michalski, P. Michelato, N. Mildner, M. Moe, F. Moglia, C. Mohr, S. Mohr, W. Möller, M. Mommerz, L. Monaco, C. Montiel, M. Moretti, I. Morozov, P. Morozov, D. Mross, J. Mueller, C. Müller, J. Müller, K. Müller, J. Munilla, A. Münnich, V. Muratov, O. Napoly, B. Näser, N. Nefedov, Reinhard Neumann, Rudolf Neumann, N. Ngada, D. Noelle, F. Obier, I. Okunev, J. A. Oliver, M. Omet, A. Oppelt, A. Ottmar, M. Oublaid, C. Pagani, R. Paparella, V. Paramonov, C. Peitzmann, J. Penning, A. Perus, F. Peters, B. Petersen, A. Petrov, I. Petrov, S. Pfeiffer, J. Pflüger, S. Philipp, Y. Pienaud, P. Pierini, S. Pivovarov, M. Planas, E. Pławski, M. Pohl, J. Polinski, V. Popov, S. Prat, J. Prenting, G. Priebe, H. Pryschelski, K. Przygoda, E. Pyata, B. Racky, A. Rathjen, W. Ratuschni, S. Regnaud-Campderros, K. Rehlich, D. Reschke, C. Robson, J. Roever, M. Roggli, J. Rothenburg, E. Rusiński, R. Rybaniec, H. Sahling, M. Salmani, L. Samoylova, D. Sanzone, F. Saretzki, O. Sawlanski, J. Schaffran, H. Schlarb, M. Schlösser, V. Schlott, C. Schmidt, F. Schmidt-Foehre, M. Schmitz, M. Schmökel, T. Schnautz, E. Schneidmiller, M. Scholz, B. Schöneburg, J. Schultze, C. Schulz, A. Schwarz, J. Sekutowicz, D. Sellmann, E. Semenov, S. Serkez, D. Sertore, N. Shehzad, P. Shemarykin, L. Shi, M. Sienkiewicz, D. Sikora, M. Sikorski, A. Silenzi, C. Simon, W. Singer, X. Singer, H. Sinn, K. Sinram, N. Skvorodnev, P. Smirnow, T. Sommer, A. Sorokin, M. Stadler, M. Steckel, B. Steffen, N. Steinhau-Kühl, F. Stephan, M. Stodulski, M. Stolper, A. Sulimov, R. Susen, J. Świerblewski, C. Sydlo, E. Syresin, V. Sytchev, J. Szuba, N. Tesch, J. Thie, A. Thiebault, K. Tiedtke, D. Tischhauser, J. Tolkiehn, S. Tomin, F. Tonisch, F. Toral, I. Torbin, A. Trapp, D. Treyer, G. Trowitzsch, T. Trublet, T. Tschentscher, F. Ullrich, M. Vannoni, P. Varela, G. Varghese, G. Vashchenko, M. Vasic, C. Vazquez-Velez, A. Verguet, S. Vilcins-Czvitkovits, R. Villanueva, B. Visentin, M. Viti, E. Vogel, E. Volobuev, R. Wagner, N. Walker, T. Wamsat, H. Weddig, G. Weichert, H. Weise, R. Wenndorf, M. Werner, R. Wichmann, C. Wiebers, M. Wiencek, T. Wilksen, I. Will, L. Winkelmann, M. Winkowski, K. Wittenburg, A. Witzig, P. Wlk, T. Wohlenberg, M. Wojciechowski, F. Wolff-Fabris, G. Wrochna, K. Wrona, M. Yakopov, B. Yang, F. Yang, M. Yurkov, I. Zagorodnov, P. Zalden, A. Zavadtsev, D. Zavadtsev, A. Zhirnov, A. Zhukov, V. Ziemann, A. Zolotov, N. Zolotukhina, F. Zummack, and D. Zybin

Subjects
Superconductivity, Optics, Materials science, Repetition (rhetorical device), business.industry, X-ray, Free-electron laser, business, Atomic and Molecular Physics, and Optics, Linear particle accelerator, Electronic, Optical and Magnetic Materials
Published
2020
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15. Volonterstvo kak sredstvo inkliuzivnogo obrazovaniia

Author

Daria G. Vashchenko

Subjects
гражданское общество, гражданская позиция, инклюзивное образование, волонтерство, толерантность
Abstract

В статье рассматриваются понятия «волонтерство», «инклюзивное образование». Обсуждаются такие вопросы, как волонтерское обеспечение инклюзивного образования, вовлечение людей с ограниченными возможностями в волонтерскую деятельность. В работе приводятся результаты опроса о толерантности, а также выводы о важности вовлечения людей с ограниченными способностями в добровольческие движения.

Published
2017

16. Assessment of ecological properties of winter wheat seeds

Author

T. P. Fedulova, G. G. Goleva, T. G. Vashchenko, V. I. Pushkareva, V. A. Ivannikov, and A. D. Golev

Subjects
Geography, Agronomy, Winter wheat, food and beverages
Abstract

Seed quality is one of the essential prerequisite for high yield formation. Ecological heterogeneity of seeds remains one of the unsolved challenges of seed production as yet. The existence of close relation between seed quality and the conditions of their growing indicates the relevance of the assessment of the ecological nature of seed heterogeneity and becomes the target of the authors’ study. Laboratory and field methods were widely used. The authors investigated different fractions of winter wheat seeds of the Alaya Zarya variety. The seeds were calibrated by width, by the specific weight, and by thickness. The studies have shown that seeds of different fractions differ in their ecological properties. Large seeds calibrated by width, seeds of low specific weight and seeds of shallow thickness were characterized by high responsiveness to vegetation conditions. The seeds of these fractions are recommended to be used in intensive cultivation technologies. The seeds of large fraction calibrated by thickness were characterized by high homeostatic properties and are recommended to be used in organic farming.

Published
2020
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17. Linearly polarized photon beam at MAX-lab

Author

Björn Nilsson, Lennart Isaksson, D. Burdeinyi, V. Ganenko, J. Brudvik, Kurt Hansen, V. Morokhovskii, Mikael Lundin, Bent Schröder, Dmytro Pugachov, K. Livingston, G. Vashchenko, and Kevin Fissum

Subjects
Physics, Nuclear and High Energy Physics, Photon, Linear polarization, Bremsstrahlung, Degree of polarization, Electron, Atomic physics, Nuclear Experiment, Polarization (waves), Instrumentation, Electromagnetic radiation, Beam (structure)
Abstract

A linearly polarized photon beam has been produced at MAX-lab using the coherent bremsstrahlung of electrons with an energy of 192.6 MeV in a 0.1 mm thick diamond crystal. The intensity and shape of the coherent maxima and their dependence on the crystal orientation are similar to the features observed at higher electron energies (~ 1 GeV) and are well described by coherent bremsstrahlung theory. The linear polarization of the uncollimated beam at the coherent peak energy ≈50–60 MeV is about 20% and can be increased to 40–45% if collimation of half the characteristic angle is used. At present the degree of polarization is high enough to allow the study of polarization observables in photo-nuclear reactions at MAX-lab in the energy range from Giant Dipole Resonance up to ≈80 MeV.

Published
2014
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18. The upgraded photon tagging facility at the MAX IV Laboratory

Author

Alan M. Nathan, Michael A. Kovash, L. S. Myers, Lars-Johan Lindgren, Pavel Golubev, R. Igarashi, Dmytro Pugachov, Bo Jakobsson, W. J. Briscoe, J. R. M. Annand, D. Burdeynyi, Per Lilja, Mikael Lundin, Anders Sandell, Bent Schröder, Lennart Isaksson, Jan-Olof Adler, G. Vashchenko, V. Ganenko, V. Morochovskyi, Kurt Hansen, J. Brudvik, K. Föhl, Gerald Feldman, Björn Nilsson, V. Takau, Grant O'Rielly, Kevin Fissum, D. Branford, Mark Boland, K. Livingston, Vladimir Avdeichikov, and P. Grabmayr

Subjects
Physics, Momentum, Nuclear physics, Nuclear and High Energy Physics, Range (particle radiation), Photon, Spectrometer, Physics::Accelerator Physics, Electron, Nuclear Experiment, Diagnostic tools, Instrumentation, Photon scattering
Abstract

A description is given of the upgraded photon tagging facility at the MAX IV Laboratory. Two magnetic spectrometers are used to momentum analyze post-bremsstrahlung electrons. The tagged photon range extends from 10 to 180 MeV with an energy resolution of about 300 keV. The system has been operated at rates up to 4×106 photons s-1 MeV −1. Different diagnostic tools are described as well as the experimental program.

Published
2013
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19. RADIATION SPECTRA OF 200 MEV ELECTRONS IN DIAMOND AND SILICON CRYSTALS AT AXIAL AND PLANAR ORIENTATIONS

Author

Mikael Lundin, Kevin Fissum, B. Shröder, Lennart Isaksson, J. Brudvikc, Kurt Hansen, V. Ganenko, D. Burdeinyi, G. Vashchenko, V. Morokhovskyi, Bengt-Olof Nilsson, and K. Livingston

Subjects
Materials science, Silicon, Diamond, chemistry.chemical_element, Electron, Radiation, engineering.material, Photon energy, Spectral line, Planar, chemistry, engineering, Atomic physics, Radiant intensity
Abstract

Results of the first experiment on studying the radiation spectra of electrons with energy 192 7 MeV in diamond and silicon crystals at axial and plane orientation performed at the MAX-lab facility were presented. At these orientation the particle's motion can be both regular, when axial and planar channeling are possible, and chaotic, when the coherent electron interaction with single strings reveals itself. Essential increase of the radiation intensity at low photon energy region, less than 15 MeV, is observed.

Published
2010
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20. THE COHERENT BREMSSTRAHLUNG BEAM AT MAX-LAB FACILITY

Author

K. Livingston, Lennart Isaksson, D. Brudvikc, Kurt Hansen, D. Burdeinyi, V. Morokhovskyi, G. Vashchenko, V. Ganenko, Mikael Lundin, Bent Schröder, Kevin Fissum, and Bengt-Olof Nilsson

Subjects
Nuclear physics, Physics, Maximal energy, Linear polarization, Nuclear Theory, Bremsstrahlung, Cathode ray, Physics::Accelerator Physics, Laser beam quality, Electron, Nuclear Experiment, Polarization (waves), Spectral line
Abstract

The linearly polarized photon beam for photonuclear researches has been produced at MAX-lab facility on the base of coherent bremsstrahlung process of electrons in a diamond crystal. Test experiments have been performed at electron energies 143.9 and 192.7 MeV with a diamond crystal 0.1 mm thick. The measured coherent bremsstrahlung spectra demonstrate typical features to be observed at higher electron energies. The polarization ~35% was obtained at coherent peak energy of ~60 MeV. The experiments have shown that produced polarized photon beam can be used for photonuclear investigations at energy range up to 60 MeV. To extend the energy range it is necessary to increase maximal energy of the electron beam up to 250 MeV.

Published
2010
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21. [Monitoring of analgesia and amnesia during the general anesthesia in surgeries made on the lungs]

Author

V M, Zhenilo, V G, Vashchenko, A A, Bychkov, M V, Zhenilo, and V N, Litvinova

Subjects
Male, Evoked Potentials, Somatosensory, Monitoring, Intraoperative, Surgical Procedures, Operative, Evoked Potentials, Auditory, Humans, Female, Amnesia, Analgesia, Anesthesia, General, Lung
Abstract

Somatosensorially evoked and auditorially evoked potentials (SSEP and AEP) were evaluated in 75 patients in different stages of general anesthesia during surgical procedures made on the lungs. N19-P23 latent increases of SSEP denoted an adequate level of analgesia. The AEP evaluation is recommended for monitoring the amnesia status during general anesthesia. N1 depression, long-latent N2 and P300 as well as disappearance of AEP and intracerebral asymmetry inversion with predominance of the bioelectric activity in the right cerebral hemisphere are regarded as objective signs of amnesia induction.

Published
2004

26. Stress-strain state of the block of a four-stroke car engine

Author

A. S. Tsybenko, N. G. Vashchenko, V. A. Potichenko, N. K. Ryazantsev, M. V. Blokh, and S. A. Nekhoroshev

Subjects
Physics, Mechanics of Materials, Stereochemistry, Block (permutation group theory), State (functional analysis)
Abstract

In designing and ref ining in ternal combust ion engines for motor t r a n s p o r t with opt imum weigh t / s i ze indica to r s , it is of g rea t i n t e re s t to work out methods of complex theore t i ca l and expe r imen ta l invest igat ion of the s t r e s s s t r a i n s ta te (SSS) of the bloek, w h i e h i s t h e pr incipal load-bear ing e lement . The conventionally used schemat iza t ion of the block in the fo rm of a spat ia l f r a m e does not sa t i s fy the r e q u i r e m e n t s of modern engine design since the calculat ions, c a r r i e d out for s i m i l a r models , yield cons iderable quanti tat ive and often a lso quali tat ive deviations f r o m the expe r imen ta l data.

Published
1980
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27. WINTER WHEAT SELECTION IN CENTRAL CHERNOZEM REGION

Author

G. G. Goleva, V. V. Znamenskaya, Т. G. Vashchenko, V. I. Pushkareva, А. V. Ivannikov, Т. P. Fedulova, А. D. Golev, and N. Т. Pavlyuk

Subjects
Crop, Agronomy, Organic farming, Growing season, Cultivar, Biology, Selective breeding, Spearman's rank correlation coefficient, Selection (genetic algorithm), Hybrid
Abstract

Research results, which were conducted in the forest-steppe of the Central Black Earth Region in the years 2000-2016, are presented. They were carried out in order to find new approaches to the selection of parental components in hybridization to make varieties of winter soft wheat with a high level of productivity, resistant to abiotic environmental factors. Agrotechnology - generally accepted in the region, research material- is the crop structure data of variety samples and hybrids from breeding nurseries. The experiments were conducted according to generally accepted methods, statistical analysis of data was carried out using the Statistica 6.1. The contingency was estimated by the Spearman coefficient, the contribution of factor signs to the resultant one was estimated by the method of multiple regression using the coefficient Beta (β). It is established that hybrids of winter wheat are characterized by higher polymorphism, the appearance of favorable transgressions. Their parental forms are selected by morphological and biological features according to the principle of different quality. When selecting high-yielding varieties which are resistant to lodging, it is advisable to make crossing, contrasting in height, forms with different spike lengths. Using the proposed methods, hybrids which are responsive to environmental conditions were made. They were used in the selection of the intensive winter wheat cultivar Alaya Zarya (since 2011 it's included in the State Register of Selective Breeding Results of the Russian Federation in the fifth region). In a number of hybrids, the contribution to the productivity of their elements practically does not depend on the conditions of the growing season, they are the basis for making the Alexia variety for organic farming (it is in State Commission of the Russian Federation on Testing and Protection of Selective Breeding Results).

Published
1970
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28. Equipment for the manipulation unit of radiotherapy departments

Author

O. G. Vashchenko, A. I. Lavrent'ev, A. I. Orlova, R. D. Bogoudinov, V. N. Frosin, and Skitovich Gp

Subjects
Radiation therapy, Medical Laboratory Technology, medicine.medical_specialty, business.industry, medicine.medical_treatment, Biomedical Engineering, Medicine (miscellaneous), Medicine, Medical physics, business, Unit (housing)
Published
1978
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29. [Rapid diagnosis of celiac-sprue syndrome]

Author

Iu A, Gaĭdar and R G, Vashchenko

Subjects
Celiac Disease, Reticulin, Time Factors, Glutens, T-Lymphocytes, Biopsy, Needle, Intestine, Small, Humans, Intestinal Mucosa, Immunohistochemistry, Antibodies, Autoantibodies
Abstract

A rapid method was developed to diagnose celiac-sprue disease, which was based on the detection of serum antibodies to gluten and simultaneous assessment of the histological structure of the upper small intestinal mucosa. Examinations of labelled lectin binding in the cryostat sections of the small intestinal mucosa, assessment of the status of the regional T-lymphocyte system, and identification of blood autoantibodies to reticuline or epithelial cells of the small intestine provide additional information on the course of the disease. The diagnosis is made within 2-3 hours.

Published
1989

31. [Interaction of the photosystem 1 reaction center with antenna chlorophyll in a pigment-protein complex isolated from pea chloroplasts]

Author

V V, Shubin, R G, Vashchenko, and N V, Karapetian

Subjects
Chlorophyll, Chloroplasts, Plants, Medicinal, Light, Photochemistry, Circular Dichroism, Photosynthetic Reaction Center Complex Proteins, Light-Harvesting Protein Complexes, Fabaceae, Plant Proteins
Abstract

Using a specially developed phosporoscopic attachment to spectropolarimeter, light induced spectra of circular dichroism (CD) in region 600-750 nm were measured for a pigment protein complex of photosystem 1 (PC-1) isolated from pea chloroplast (chlorophyll : P700 = 40). Minor components at 672 and 678 nm are observed in light induced spectra besides the components of dimer splitting of P700 Qy transition at 691 and 698 nm. Haussian deconvolution of light induced CD spectra of P700 and low temperature CD spectrum of PC-1 indicates that minor components are due to forms of antenna chlorophylls Chl672 and Chl678, rotational strength of that is changed by 2-4% as a result of P700 oxidation. Long term incubation of PC-1 with Triton X-100 inhibits P700 and destroys longwave optically active chlorophyll forms. A strong relation between dichroic density of 693 nm band in CD spectrum of PC-1 and the value of light induced absorption change at 698 nm could be used to determine P700 concentration on the basis of CD spectrum of PC-1. Such a relation shows that Chl693 is an important component of photo-system 1 reaction center. It is suggested that P700 is not an isolated dimer but it is included in the local complex from 8-10 chlorophyll molecules (Chl672, Chl678, Chl686, Chl693).

Published
1985

37. Logistics Management as a Tool to Achieve Competitive Advantages of the Enterprise Trade

Author

Victoria V. Prokhorova, Oksana N. Kolomyts, Alyona I. Nenasheva, Nickolay A. Sholukha, and Pavel G. Vashchenko

Subjects
management, administration, logistics, competitive advantage, Management. Industrial management, HD28-70, Business, HF5001-6182
Abstract

The need for logistics management explained convent-house reasons, among which we distinguish the main. One of them – the development of competition caused by the transition from a seller’s market to a buyer’s market. Cash invested in the sphere of distribution, began to influence the position of the supplier on the market is much stronger than the same money invested in the sphere of production. The logistically organized material leading chains cost of goods delivered to the final consumer was lower than the cost of the same goods held by the traditional way. Emerging difference provides the participants a competitive advantage, not dependent on the size of included capital, and the ability to organize the logistics process. In addition, using the logistics providers can guarantee the delivery on time the right amount of product required quality and represent for the consumer is much more valuable than suppliers that the reliability of such assurances do not provide.

Published
2016

38. Demonstration of ultra-high dose rate electron irradiation at FLASH lab @PITZ.

Author

Li XK, Amirkhanyan Z, Grebinyk A, Gross M, Komar Y, Riemer F, Asoyan A, Boonpornprasert P, Borchert P, Davtyan H, Dmytriiev D, Frohme M, Hoffmann A, Krasilnikov M, Loisch G, Lotfi Z, Müller F, Schmitz M, Obier F, Oppelt A, Philipp S, Richard C, Vashchenko G, Villani D, Worm S, and Stephan F

Subjects
Radiation Dosage, DNA radiation effects, DNA Damage, Electrons therapeutic use, Monte Carlo Method
Abstract

Objective. The photo injector test facility at DESY in Zeuthen (PITZ) is building up an R&D platform, known as FLASH lab @PITZ, for systematically studying the FLASH effect in cancer treatment with its high-brightness electron beams, which can provide a uniquely large dose parameter range for radiation experiments. In this paper, we demonstrate the capabilities by experiments with a reduced parameter range on a startup beamline and study the potential performance of the full beamline by simulations. Approach. To measure the dose, Gafchromic films are installed both in front of and after the samples; Monte Carlo simulations are conducted to predict the dose distribution during beam preparation and help understand the dose distribution inside the sample. Plasmid DNA is irradiated under various doses at conventional and ultra-high dose rate (UHDR) to study the DNA damage by radiations. Start-to-end simulations are performed to verify the performance of the full beamline. Main results. On the startup beamline, reproducible irradiation has been established with optimized electron beams and the delivered dose distributions have been measured with Gafchromic films and compared to FLUKA simulations. The functionality of this setup has been further demonstrated in biochemical experiments at conventional dose rate of 0.05 Gy s -1 and UHDR of several 10 5  Gy s -1 and a varying dose up to 60 Gy, with the UHDR experiments finished within a single RF pulse (less than 1 millisecond); the observed conformation yields of the irradiated plasmid DNA revealed its dose-dependent radiation damage. The upgrade to the full FLASH lab @PITZ beamline is justified by simulations with homogeneous radiation fields generated by both pencil beam scanning and scattering beams. Significance. With the demonstration of UHDR irradiation and the simulated performance of the new beamline, FLASH lab @PITZ will serve as a powerful platform for studying the FLASH effects in cancer treatment., (Creative Commons Attribution license.)

Published
2025
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39. Identification of Avian Corticosteroid-binding Globulin (SerpinA6) Reveals the Molecular Basis of Evolutionary Adaptations in SerpinA6 Structure and Function as a Steroid-binding Protein.

Author

Vashchenko G, Das S, Moon KM, Rogalski JC, Taves MD, Soma KK, Van Petegem F, Foster LJ, and Hammond GL

Subjects
Adaptation, Physiological, Amino Acid Sequence, Animals, Avian Proteins chemistry, Chickens blood, Chickens genetics, Crystallography, X-Ray, Finches blood, Finches genetics, Glycosylation, Models, Molecular, Phylogeny, Rats, Sequence Homology, Amino Acid, Sparrows blood, Sparrows genetics, Transcortin chemistry, Avian Proteins blood, Avian Proteins genetics, Birds blood, Birds genetics, Evolution, Molecular, Transcortin genetics, Transcortin metabolism
Abstract

Corticosteroid-binding globulin (CBG) was isolated from chicken serum and identified by mass spectrometry and genomic analysis. This revealed that the organization and synteny of avian and mammalian SerpinA6 genes are conserved. Recombinant zebra finch CBG steroid-binding properties reflect those of the natural protein in plasma and confirm its identity. Zebra finch and rat CBG crystal structures in complex with cortisol resemble each other, but their primary structures share only ∼40% identity, and their steroid-binding site topographies differ in several unexpected ways. Remarkably, a tryptophan that anchors ligands in mammalian CBG steroid-binding sites is replaced by an asparagine. Phylogenetic comparisons show that reptilian CBG orthologs share this unexpected property. Glycosylation of this asparagine in zebra finch CBG does not influence its steroid-binding affinity, but we present evidence that it may participate in protein folding and steroid-binding site formation. Substitutions of amino acids within zebra finch CBG that are conserved only in birds reveal how they contribute to their distinct steroid-binding properties, including their high (nanomolar) affinities for glucocorticoids, progesterone, and androgens. As in mammals, a protease secreted by Pseudomonas aeruginosa cleaves CBG in zebra finch plasma within its reactive center loop and disrupts steroid binding, suggesting an evolutionarily conserved property of CBGs. Measurements of CBG mRNA in zebra finch tissues indicate that liver is the main site of plasma CBG production, and anti-zebra finch CBG antibodies cross-react with CBGs in other birds, extending opportunities to study how CBG regulates the actions of glucocorticoids and sex steroids in these species., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)

Published
2016
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40. Multi-copper oxidases and human iron metabolism.

Author

Vashchenko G and MacGillivray RT

Subjects
Absorption, Cation Transport Proteins metabolism, Ceruloplasmin metabolism, Copper metabolism, Enterocytes metabolism, Homeostasis, Humans, Intestine, Small drug effects, Intestine, Small metabolism, Iron blood, Membrane Proteins metabolism, Oxidation-Reduction, Protein Conformation, Reactive Oxygen Species metabolism, Ferroportin, Iron pharmacokinetics, Oxidoreductases metabolism
Abstract

Multi-copper oxidases (MCOs) are a small group of enzymes that oxidize their substrate with the concomitant reduction of dioxygen to two water molecules. Generally, multi-copper oxidases are promiscuous with regards to their reducing substrates and are capable of performing various functions in different species. To date, three multi-copper oxidases have been detected in humans--ceruloplasmin, hephaestin and zyklopen. Each of these enzymes has a high specificity towards iron with the resulting ferroxidase activity being associated with ferroportin, the only known iron exporter protein in humans. Ferroportin exports iron as Fe(2+), but transferrin, the major iron transporter protein of blood, can bind only Fe(3+) effectively. Iron oxidation in enterocytes is mediated mainly by hephaestin thus allowing dietary iron to enter the bloodstream. Zyklopen is involved in iron efflux from placental trophoblasts during iron transfer from mother to fetus. Release of iron from the liver relies on ferroportin and the ferroxidase activity of ceruloplasmin which is found in blood in a soluble form. Ceruloplasmin, hephaestin and zyklopen show distinctive expression patterns and have unique mechanisms for regulating their expression. These features of human multi-copper ferroxidases can serve as a basis for the precise control of iron efflux in different tissues. In this manuscript, we review the biochemical and biological properties of the three human MCOs and discuss their potential roles in human iron homeostasis.

Published
2013
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41. Functional role of the putative iron ligands in the ferroxidase activity of recombinant human hephaestin.

Author

Vashchenko G and Macgillivray RT

Subjects
Cells, Cultured, Ceruloplasmin chemistry, Humans, Ligands, Membrane Proteins chemistry, Membrane Proteins genetics, Mutagenesis, Site-Directed, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins metabolism, Ceruloplasmin metabolism, Iron metabolism, Membrane Proteins metabolism
Abstract

Hephaestin is a multicopper ferroxidase expressed mainly in the mammalian small intestine. The ferroxidase activity of hephaestin is thought to play an important role during iron export from intestinal enterocytes and the subsequent iron loading of the blood protein transferrin, which delivers iron to the tissues. Structurally, the ectodomain of hephaestin is predicted to resemble ceruloplasmin, the soluble ferroxidase of blood. In this study, the human hephaestin ectodomain was expressed in baby hamster kidney cells and purified to electrophoretic homogeneity. Ion exchange chromatography of purified recombinant human hephaestin (rhHp) resulted in the isolation of hephaestin fractions with distinct catalytic and spectroscopic properties. The fraction of rhHp with the highest enzymatic activity also showed an enhanced molar absorptivity at 600 nm, characteristic of type 1 copper sites. Kinetic analysis revealed that rhHp possesses both high-affinity and low-affinity binding sites for ferrous iron. To investigate the role of particular residues in iron specificity of hephaestin, mutations of putative iron ligands were introduced into rhHp using site-directed mutagenesis. Kinetic analysis of ferroxidation rates of wild-type rhHp and mutants demonstrated the important roles of hephaestin residues E960 and H965 in the observed ferroxidase activity.

Published
2012
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42. Oxidation of organic and biogenic amines by recombinant human hephaestin expressed in Pichia pastoris.

Author

Vashchenko G, Bleackley MR, Griffiths TA, and MacGillivray RT

Subjects
Ceruloplasmin metabolism, Copper analysis, Gene Expression, Humans, Iron metabolism, Membrane Proteins chemistry, Membrane Proteins genetics, Membrane Proteins isolation & purification, Oxidation-Reduction, Pichia genetics, Protein Structure, Tertiary, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins isolation & purification, Substrate Specificity, Biogenic Amines metabolism, Membrane Proteins metabolism, Recombinant Proteins metabolism
Abstract

Hephaestin is a multicopper ferroxidase involved in iron absorption in the small intestine. Expressed mainly on the basolateral surface of duodenal enterocytes, hephaestin facilitates the export of iron from the intestinal epithelium into blood by oxidizing Fe(2+) into Fe(3+), the only form of iron bound by the plasma protein transferrin. Structurally, the human hephaestin ectodomain is predicted to resemble ceruloplasmin, the major multicopper oxidase in blood. In addition to its ferroxidase activity, ceruloplasmin was reported to oxidize a wide range of organic compounds including a group of physiologically relevant substrates (biogenic amines). To study oxidation of organic substrates, the human hephaestin ectodomain was expressed in Pichia pastoris. The purified recombinant hephaestin has an average copper content of 4.2 copper atoms per molecule. The K(m) for Fe(2+) of hephaestin was determined to be 3.2μM which is consistent with the K(m) values for other multicopper ferroxidases. In addition, the K(m) values of hephaestin for such organic substrates as p-phenylenediamine and o-dianisidine are close to values determined for ceruloplasmin. However, in contrast to ceruloplasmin, hephaestin was incapable of direct oxidation of adrenaline and dopamine implying a difference in biological substrate specificities between these two homologous ferroxidases., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Published
2011
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