276 results on '"Järvinen, J."'
Search Results
2. A large octupole magnetic trap for research with atomic hydrogen
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Ahokas, J., Semakin, A., Järvinen, J., Hanski, O., Laptiyenko, A., Dvornichenko, V., Salonen, K., Burkley, Z., Crivelli, P., Golovizin, A., Nesvizhevsky, V., Nez, F., Yzombard, P., Widmann, E., and Vasiliev, S.
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Physics - Atomic Physics ,Physics - Instrumentation and Detectors - Abstract
We describe the design and performance of a large magnetic trap for storing and cooling of atomic hydrogen (H). The trap operates in the vacuum space of a dilution refrigerator at a temperature of 1.5 K. Aiming at a large volume of the trap we implemented the octupole configuration of linear currents (Ioffe bars) for the radial confinement, combined with two axial pinch coils and a 3 T solenoid for the cryogenic H dissociator. The octupole magnet consists of eight race-track segments which are compressed towards each other with magnetic forces. This provides a mechanically stable and robust construction with a possibility of replacement or repair of each segment. A maximum trap depth of 0.54 K (0.8 T) was reached, corresponding to an effective volume of 0.5 liters for hydrogen gas at 50 mK. This is an order of magnitude larger than ever used for trapping atoms.
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- 2021
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3. Nuclear-Polarized Phases of H Atoms Embedded in Solid Molecular Hydrogen Films
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Sheludiakov, S., Lee, D. M., Khmelenko, V. V., Ahokas, J., Järvinen, J., and Vasiliev, S.
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- 2022
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4. Spin Waves in Quantum Gases --- The Quality Factor of the Identical Spin Rotation Effect
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Lehtonen, L., Vainio, O., Ahokas, J., Järvinen, J., Sheludyakov, S., Suominen, K. -A., Vasiliev, S., Khmelenko, V., and Lee, D. M.
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Condensed Matter - Quantum Gases - Abstract
Our recent experimental work on electron spin waves in atomic hydrogen gas has prompted a revisit of the theory of the Identical Spin Rotation Effect (ISRE). A key characteristic determining the properties of the spin waves is the quality factor of ISRE. Unfortunately, calculating this quality factor takes some toil. In this paper we summarize some results of the ISRE theory in dilute gases. We also derive asymptotic formulae for the quality factor and examine their accuracy for hydrogen and $^3$He., Comment: 13 pages, 3 figures
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- 2018
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5. Dynamic Polarization and Relaxation of 75As Nuclei in Silicon at High Magnetic Field and Low Temperature
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Järvinen, J., Ahokas, J., Sheludyakov, S., Vainio, O., Lehtonen, L., Vasiliev, S., Zvezdov, D., and Vlasenko, L.
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Condensed Matter - Materials Science - Abstract
We present the results of experiments on dynamic nuclear polarization and relaxation of 75As in silicon crystals. Experiments are performed in strong magnetic fields of 4.6 T and temperatures below 1 K. At these conditions donor electron spins are fully polarized, and the allowed and forbidden ESR transitions are well resolved. We demonstrate effective nuclear polarization of 75As nuclei via the Overhauser effect on the time scale of several hundred seconds. Excitation of the forbidden transitions leads to a polarization through the solid effect. The relaxation rate of donor nuclei has strong temperature dependence characteristic of Orbach process., Comment: 9 pages, 7 figures
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- 2016
6. Dynamic nuclear polarization and relaxation of H and D atoms in solid mixtures of hydrogen isotopes
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Sheludiakov, S., Ahokas, J., Järvinen, J., Vainio, O., Lehtonen, L., Vasiliev, S., Lee, D. M., and Khmelenko, V. V.
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Physics - Atomic and Molecular Clusters ,Condensed Matter - Mesoscale and Nanoscale Physics ,Physics - Chemical Physics - Abstract
We report on a study of Dynamic Nuclear Polarization and electron and nuclear spin relaxation of atomic hydrogen and deuterium in solid molecular matrices of H$_{2}$, D$_{2}$, and HD mixtures. The electron and nuclear spin relaxation times ($T_{1e}$ and $T_{1N}$) were measured within the temperature range 0.15-2.5$\,$K in a magnetic field of 4.6 T, conditions which ensure a high polarization of electron spins. We found that $T_{1e}$ is nearly temperature independent in this temperature range, while $T_{1N}$ decreased by 2 orders of magnitude. Such strong temperature dependence is typical for the nuclear Orbach mechanism of relaxation via the electron spins. We found that the nuclear spins of H atoms in solid D$_{2}$ and D$_{2}:$HD can be efficiently polarized by the Overhauser effect. Pumping the forbidden transitions of H atoms also leads to DNP, with the efficiency strongly dependent on the concentration of D atoms. This behaviour indicates the Cross effect mechanism of the DNP and nuclear relaxation, which turns out to be well resolved in the conditions of our experiments. Efficient DNP of H atoms was also observed when pumping the middle D line located in center of the ESR spectrum. This phenomenon can be explained in terms of clusters or pairs of H atoms with strong exchange interaction. These clusters have partially allowed transitions in the center of the ESR spectrum and DNP may be created via the resolved Cross effect.
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- 2016
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7. Identical Spin Rotation Effect and Electron Spin Waves in Quantum Gas of Atomic Hydrogen
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Lehtonen, L., Vainio, O., Ahokas, J., Järvinen, J., Novotny, S., Sheludyakov, S., Suominen, K. -A., Vasiliev, S., Khmelenko, V., and Lee, D. M.
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Condensed Matter - Quantum Gases ,Quantum Physics - Abstract
We present an experimental study of electron spin waves in atomic hydrogen gas compressed to high densities of $\sim 5 \times 10^{18}$ cm$^{-3}$ at temperatures ranging from 0.26 to 0.6 K in strong magnetic field of 4.6 T. Hydrogen gas is in a quantum regime when the thermal de Broglie wavelength is much larger than the s-wave scattering length. In this regime the identical particle effects play major role in atomic collisions and lead to the Identical Spin Rotation effect (ISR). We observed a variety of spin wave modes caused by this effect with strong dependence on the magnetic potential caused by variations of the polarizing magnetic field. We demonstrate confinement of the ISR modes in the magnetic potential and manipulate their properties by changing the spatial profile of magnetic field. We have found that at a high enough density of H gas the magnons accumulate in their ground state in the magnetic trap and exhibit long coherence, which has a profound effect on the electron spin resonance spectra. Such macroscopic accumulation of the ground state occurs at a certain critical density of hydrogen gas, where the chemical potential of the magnons becomes equal to the energy of their ground state in the trapping potential., Comment: 16 pages, 15 figures
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- 2016
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8. ESR study of atomic hydrogen and tritium in solid T$_{2}$ and T$_{2}$:H$_{2}$ matrices below 1K
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Sheludiakov, S., Ahokas, J., Järvinen, J., Vainio, O., Lehtonen, L., Zvezdov, D., Vasiliev, S., Lee, D. M., and Khmelenko, V. V.
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Condensed Matter - Other Condensed Matter ,Physics - Atomic Physics - Abstract
We report on the first ESR study of atomic hydrogen and tritium stabilized in a solid T$_{2}$ and T$_{2}$:H$_{2}$ matrices down to 70$\,$mK. The concentrations of T atoms in pure T$_{2}$ approached $2\times10^{20}$cm$^{-3}$ and record-high concentrations of H atoms $\sim1\times10^{20}$cm$^{-3}$ were reached in T$_{2}$:H$_{2}$ solid mixtures where a fraction of T atoms became converted into H due to the isotopic exchange reaction T+H$_2\rightarrow$TH+H. The maximum concentrations of unpaired T and H atoms was limited by their recombination which becomes enforced by efficient atomic diffusion due to a presence of a large number of vacancies and phonons generated in the matrices by $\beta$-particles. Recombination also appeared in an explosive manner both being stimulated and spontaneously in thick films where sample cooling was insufficient. We suggest that the main mechanism for H and T migration is physical diffusion related to tunneling or hopping to vacant sites in contrast to isotopic chemical reactions which govern diffusion of H and D atoms created in H$_{2}$ and D$_{2}$ matrices by other methods.
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- 2016
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9. Digital skills among youth: A dataset from a three-wave longitudinal survey in six European countries
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Machackova, H, Jaron Bedrosova, M, Muzik, M, Zlamal, R, Fikrlova, J, Literova, A, Dufkova, E, Smahel, D, Boomgaarden, H, Song, H, Tolochko, P, D'Haenens, L, Joris, W, Kalmus, V, Tikerperi, M, Opermann, S, Napp, M, Soidla, I, Uibos, A, Soo, K, Salmela-Aro, K, Järvinen, J, Mannerström, R, Suvila, E, Waechter, N, Brando, C, Kadera, S, Mascheroni, G, Cino, D, Lombi, L, van Deursen, A, van Laar, E, Pyżalski, J, Walter, N, Iwanicka, A, Ponte, C, Batista, S, Baptista, R, Schneider, L, Helsper, E, Machackova, Hana, Jaron Bedrosova, Marie, Muzik, Michal, Zlamal, Rostislav, Fikrlova, Jana, Literova, Anna, Dufkova, Eliska, Smahel, David, Boomgaarden, Hajo, Song, Hyunjin, Tolochko, Petro, d'Haenens, Leen, Joris, Willem, Kalmus, Veronika, Tikerperi, Mari-Liis, Opermann, Signe, Napp, Marit, Soidla, Indrek, Uibos, Andre, Soo, Kadri, Salmela-Aro, Katariina, Järvinen, Jussi, Mannerström, Rasmus, Suvila, Erkki, Waechter, Natalia, Brando, Christin, Kadera, Stepanka, Mascheroni, Giovanna, Cino, Davide, Lombi, Linda, van Deursen, Alexander, van Laar, Ester, Pyżalski, Jacek, Walter, Natalia, Iwanicka, Agnieszka, Ponte, Cristina, Batista, Susana, Baptista, Rita, Schneider, Luc, Helsper, Ellen Johanna, Machackova, H, Jaron Bedrosova, M, Muzik, M, Zlamal, R, Fikrlova, J, Literova, A, Dufkova, E, Smahel, D, Boomgaarden, H, Song, H, Tolochko, P, D'Haenens, L, Joris, W, Kalmus, V, Tikerperi, M, Opermann, S, Napp, M, Soidla, I, Uibos, A, Soo, K, Salmela-Aro, K, Järvinen, J, Mannerström, R, Suvila, E, Waechter, N, Brando, C, Kadera, S, Mascheroni, G, Cino, D, Lombi, L, van Deursen, A, van Laar, E, Pyżalski, J, Walter, N, Iwanicka, A, Ponte, C, Batista, S, Baptista, R, Schneider, L, Helsper, E, Machackova, Hana, Jaron Bedrosova, Marie, Muzik, Michal, Zlamal, Rostislav, Fikrlova, Jana, Literova, Anna, Dufkova, Eliska, Smahel, David, Boomgaarden, Hajo, Song, Hyunjin, Tolochko, Petro, d'Haenens, Leen, Joris, Willem, Kalmus, Veronika, Tikerperi, Mari-Liis, Opermann, Signe, Napp, Marit, Soidla, Indrek, Uibos, Andre, Soo, Kadri, Salmela-Aro, Katariina, Järvinen, Jussi, Mannerström, Rasmus, Suvila, Erkki, Waechter, Natalia, Brando, Christin, Kadera, Stepanka, Mascheroni, Giovanna, Cino, Davide, Lombi, Linda, van Deursen, Alexander, van Laar, Ester, Pyżalski, Jacek, Walter, Natalia, Iwanicka, Agnieszka, Ponte, Cristina, Batista, Susana, Baptista, Rita, Schneider, Luc, and Helsper, Ellen Johanna
- Abstract
This dataset provides longitudinal survey data from a European project, ySKILLS, which was focused on the role of digital skills in youths’ development. It contains data from 10,821 participants from Grades 6–10 (in Wave 1) in Estonia, Finland, Germany, Italy, Poland, and Portugal. The data was collected between Spring 2021 and Spring 2023, the participants were recruited through schools, where the data collection also took place, except for online data collections due to restrictions caused by COVID-19. The dataset is novel in its multidimensional approach to the construct of digital literacy. It provides insight into the development of digital skills in youth and the role of digital skills and internet usage in youths’ positive and negative online experiences and wellbeing. It also contains data that allows for the analysis of the role of digital skills in class networks. The data are beneficial for researchers interested in the examination of youths’ online skills, internet usage, online experiences, and wellbeing from a longitudinal perspective.
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- 2024
10. Tunneling chemical exchange reaction $\textrm{D}+\textrm{HD}\rightarrow\textrm{D}_{2}+\textrm{H}$ in solid HD and D$_2$ at temperatures below 1$\,$K
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Sheludiakov, S., Ahokas, J., Järvinen, J., Zvezdov, D., Lehtonen, L., Vainio, O., Vasiliev, S., Lee, D. M., and Khmelenko, V. V.
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Physics - Chemical Physics - Abstract
We report on a study of the exchange tunneling reaction D+HD$\rightarrow$D$_{2}$+H in a pure solid HD matrix and in a D$_{2}$ matrix with 0.23$\%$ HD admixture at temperatures between 130$\,$mK and 1.5$\,$K. We found that the exchange reaction rates, $k_{exHD}\sim3\times10^{-27}$cm$^{3}$s$^{-1}$ in the pure HD matrix, and $k_{exD_{2}}=9(4)\times10^{-28}$cm$^{-3}$ in the D$_{2}$ matrix are nearly independent of temperature within this range. This confirms quantum tunnelling nature of these reactions, and their ability to proceed at temperatures down to absolute zero. Based on these observations we concluded that exchange tunneling reaction H+H$_{2}\rightarrow$H$_{2}$+H should also proceed in a H$_{2}$ matrix at the lowest temperatures. On contrary, the recombination of H atoms in solid H$_{2}$ and D atoms in solid D$_{2}$ is substantially suppressed at the lowest temperatures as a result of increasing of violation for resonance tunneling of atoms when they approach each other.
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- 2015
11. Bose-Einstein condensation of magnons in atomic hydrogen gas
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Vainio, O., Ahokas, J., Järvinen, J., Lehtonen, L., Novotny, S., Sheludiakov, S., Suominen, K. -A., Vasiliev, S., Zvezdov, D., Khmelenko, V. V., and Lee, D. M.
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Condensed Matter - Quantum Gases - Abstract
We report on experimental observation of BEC-like behaviour of quantized electron spin waves (magnons) in a dense gas of spin polarized atomic hydrogen. The magnons are trapped and controlled with inhomogeneous magnetic fields, and described by a Schr\"odinger-like wave equation, in analogy to the BEC experiments with neutral atoms. We have observed the appearance of a sharp feature in the ESR spectrum displaced from the normal spin wave spectrum. We believe that this observation corresponds to a sudden growth of the ground state population of the magnons and emergence of their spontaneous coherence for hydrogen gas densities exceeding a critical value, dependent on the trapping potential. We interpret the results as a BEC of non-equilibrium magnons which were formed by applying the rf power., Comment: 5 pages, 3 figures Supplemental material: 3 pages, 3 figures. Accepted for publication in Physical Review Letters
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- 2015
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12. Microscopic control of $^{29}$Si nuclear spins near phosphorus donors in silicon
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Järvinen, J., Zvezdov, D., Ahokas, J., Sheludyakov, S., Vainio, O., Lehtonen, L., Vasiliev, S., Fujii, Y., Mitsudo, S., Mizusaki, T., Gwak, M., Lee, SangGap, Lee, Soonchil, and Vlasenko, L.
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Physics - Atomic and Molecular Clusters ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We demonstrate an efficient control of $^{29}$Si nuclear spin orientation for specific lattice sites near $^{31}$P donors in silicon crystals at temperatures below 1 K and in high magnetic field of 4.6 T. Excitation of the forbidden electron-nuclear transitions leads to a pattern of narrow holes and peaks in the ESR lines of $^{31}$P. The pattern originates from dynamic polarization the $^{29}$Si nuclear spins near the donors via the solid effect. This method can be used for initialization of qubits based on $^{29}$Si nuclear spins in the all-silicon quantum computer. In comparison, polarization of $^{29}$Si performed by pumping the allowed ESR transitions, did not create any patterns. Instead, a single narrow spectral hole was burnt in the ESR line. The difference is explained by a rapid spin diffusion during the microwave pumping of the allowed transitions.
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- 2014
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13. Efficient Dynamic Polarization of Phosphorus Nuclei in Silicon in Strong Magnetic Fields and Low Temperatures
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Järvinen, J., Zvezdov, D., Ahokas, J., Sheludyakov, S., Vainio, O., Lehtonen, L., Vasiliev, S., Fujii, Y., Mitsudo, S., Mizusaki, T., Gwak, M., Lee, SangGap, Lee, Soonchil, and Vlasenko, L.
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Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We demonstrate that the dynamic nuclear polarization (DNP) of phosphorus donors in silicon can be very effective in a magnetic field of 4.6 T and at temperatures below 1 K. The DNP occurs due to the Overhauser effect following a cross relaxation via the forbidden flip-flop or flip-flip transitions. Nuclear polarization values $P>0.98$ were reached after 20 min of pumping with 0.4 $\mu$W of microwave power. We evaluated that the ratio of hyperfine state populations increased by three orders of magnitude after 2 hours of pumping, and an extremely pure nuclear spin system containing $<10^{-11}$ of the other spin state can be created. An inverted DNP has been obtained by pumping the low field ESR line of P followed by the flip-flip cross relaxation. This transition has much smaller relaxation rate and required substantially longer pumping times. We found that the nuclear polarization dynamics deviates substantially from a simple exponential function. The evolution of the polarization is characterized by two time constants $T^{'}_{ac}\approx$15 s in the beginning, and $T^{"}_{ac}\approx$1100 s for long pumping time. Temperature dependence of the nuclear relaxation rate of $^{31}$P was studied down to 0.75 K, below which the relaxation time became too long to be measured. The nuclear polarization followed a bi-exponential time dependence during relaxation. We suggest that the non-exponential behavior of DNP dynamics and the subsequent relaxation is mediated by the nuclei of $^{29}$Si surrounding $^{31}$P donors, which affect the transition probabilities of the forbidden cross-relaxation processes.
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- 2014
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14. Prime filter structures of pseudocomplemented Kleene algebras and representation by rough sets
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Järvinen, J. and Radeleczki, S.
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- 2020
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15. Thermal compression of atomic hydrogen on helium surface
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Järvinen, J., Ahokas, J., and Vasiliev, S.
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Condensed Matter - Other Condensed Matter - Abstract
We describe experiments with spin-polarized atomic hydrogen gas adsorbed on liquid $^{4}$He surface. The surface gas density is increased locally by thermal compression up to $5.5\times10^{12}$ cm$^{-2}$ at 110 mK. This corresponds to the onset of quantum degeneracy with the thermal de-Broglie wavelength being 1.5 times larger than the mean interatomic spacing. The atoms were detected directly with a 129 GHz electron-spin resonance spectrometer probing both the surface and the bulk gas. This, and the simultaneous measurement of the recombination power, allowed us to make accurate studies of the adsorption isotherm and the heat removal from the adsorbed hydrogen gas. From the data, we estimate the thermal contact between 2D hydrogen gas and phonons of the helium film. We analyze the limitations of the thermal compression method and the possibility to reach the superfluid transition in 2D hydrogen gas., Comment: 20 pages, 11 figures
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- 2006
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16. Establishing the European diagnostic reference levels for interventional cardiology
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Siiskonen, T., Ciraj-Bjelac, O., Dabin, J., Diklic, A., Domienik-Andrzejewska, J., Farah, J., Fernandez, J.M., Gallagher, A., Hourdakis, C.J., Jurkovic, S., Järvinen, H., Järvinen, J., Knežević, Ž., Koukorava, C., Maccia, C., Majer, M., Malchair, F., Riccardi, L., Rizk, C., Sanchez, R., Sandborg, M., Merce, M. Sans, Segota, D., Sierpowska, J., Simantirakis, G., Sukupova, L., Thrapsanioti, Z., and Vano, E.
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- 2018
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17. Electrons Trapped in Solid Neon–Hydrogen Mixtures Below 1K
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Sheludiakov, S., Ahokas, J., Järvinen, J., Lehtonen, L., Vasiliev, S., Dmitriev, Yu. A., Lee, D. M., and Khmelenko, V. V.
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- 2019
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18. Studies of accumulation rate of H atoms in solid H2 films exposed to 0.1 and 5.7 keV electrons
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Sheludiakov, S., primary, Wetzel, C. K., additional, Lee, D. M., additional, Khmelenko, V. V., additional, Järvinen, J., additional, Ahokas, J., additional, and Vasiliev, S., additional
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- 2023
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19. Constructing the accurate forecast:an actor-network theory approach
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Henttu-Aho, T. (Tiina), Järvinen, J. T. (Janne T.), Lassila, E. M. (Erkki M.), Henttu-Aho, T. (Tiina), Järvinen, J. T. (Janne T.), and Lassila, E. M. (Erkki M.)
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Purpose: This paper empirically demonstrates the major organizational events of a rolling forecasting process and the roles of controllers therein. In particular, this study aims to investigate how the understanding of a “realistic forecast” is translated and questioned by various mediators in the rolling forecasting process and how it affects the quality of planning as the ultimate accuracy of forecasts is seen as important. Design/methodology/approach: This study follows an actor-network theory (ANT) approach and maps the key points of translation in the rolling forecasting process by inspecting the roles of mediators. This qualitative case study is based on interviews with controllers and managers involved in the forecasting process in a single manufacturing company. Findings: The paper identified two episodes of translation in the forecasting process, in which the forecast partially stabilized to create room for managerial discussion and debate. The abilities of controllers to infiltrate various functional groups and calculative practices appeared to be one way to control the accuracy of forecasting, although this was built on a façade of neutrality. Originality/value: Prior literature identifies the aims of interactive planning processes as being to improve the quality of planning. The authors apply ANT to better understand the nature of mediators in constructing an entity called a “realistic rolling forecast”.
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- 2023
20. D-vitamiini ja sen vaikutus immuunijärjestelmään
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Järvinen, J. (Jasmin) and Järvinen, J. (Jasmin)
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Tiivistelmä. D-vitamiinin vaikutusta immuunijärjestelmään on tutkittu läpi vuosien, mutta vuonna 2019 maailmanlaajuinen pandemia antoi ponnahduslaudan sen immuunijärjestelmää tehostavien vaikutuksien tutkimiselle. D-vitamiinia tarvitaan normaaliin immuunipuolustukseen, ja lumekontrolloidut tutkimukset ovat osoittaneet, että veren kalsidiolin ollessa alle 25 nmol/l, eli vaikeaan D-vitamiinipuutokseen liittyy suurentunut ylähengitystieinfektion riski. Väestötutkimukset viittaavat myös siihen, että infektioriski voi olla suurentunut jo alle 75 nmol/l pitoisuudella (Paakkari, 2022). Paakkari kirjoittaa Lääketieteellinen aikakausikirja Duodecim:issa (2022) myös siitä, että koronavirusinfektioon sairastumisen riskin on todettu olleen suurempi niillä, joiden veren kalsidiolipitoisuus on ollut alle 50 tai 75 nmol/l. Kuitenkin toistaiseksi tiedetään vain, että vaikka riittävä D-vitamiinitaso vaikuttaa suojaavan infektiolta, jo alkaneessa infektiossa sen merkitys on epävarma. D-vitamiinin tiedetään vaikuttavan luuston terveyteen ja kehon kalsiumtasapainoon, mutta on ilmeistä, ettei luusto ole ainoa säätelykohde. D-vitamiinilla on vaikutuksia noin 1 000 geeniin lähes kaikissa elimistön kudoksissa (Paakkari, 2022), mikä viittaa sen laaja-alaisiin tehtäviin kehossa. Pienimuotoiset plasebokontrolloidut tutkimukset ovat osoittaneet, että D-vitamiinihoidolla on edullisia vaikutuksia tulehdusta mittaaviin veriarvoihin ja mahdollisesti taudin kulkuun. Koronavirusinfektion tutkimuksissa on viitteitä siitä, että vaikean, tehohoitoa vaativan infektion vaara on suurempi, jos veren D-vitamiinipitoisuus on matala (Paakkari, 2022).
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- 2023
21. Big data in the margins of accounting:the mediating role of calculative practices in a digital environment
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Järvinen, J. (Janne), Lepistö, S. (Sinikka), Lassila, E. (Erkki), Järvinen, J. (Janne), Lepistö, S. (Sinikka), and Lassila, E. (Erkki)
- Abstract
This dissertation concerns the implications of the digitalization and related big data technologies for management accounting. It increases understanding of how these new means of quantification and calculation are intertwined with the management accounting expertise that has traditionally generated and linked calculable spaces and calculable selves for liberal programs of government. By highlighting the performative characteristics of digital space, the dissertation provides a fresh way to approach “the digital” from the management accounting perspective. An increasing amount of literature has examined the disruptive digital transformation. However, there is still very little empirical and critically tuned research on the potential implications of this transformation for management accounting in its organizational and social contexts. This dissertation adopts an interdisciplinary perspective on accounting and problematizes the simplistic technical view of digitalization and big data technologies by taking a more holistic approach to the subject. This dissertation is composed of three interrelated essays, which together bring forward the mediating and transformative role of calculative practices of accounting in the digital environment. The empirical findings show, first, how data analytics acts as a performative engine that generates coordination and control in creative digital development organizations. Second, the findings show how the governing of individuals’ everyday lives takes place in “free” digital application markets. Third, the findings show how specific characteristics that can be attributed to the digital calculable space have implications for the calculative expertise of management accounting. This dissertation argues that the “uniqueness” of big data technologies comes mainly from their potential to economize and govern new territories of individuals’ private domains. However, it seems that these calculative technologies are, at least at pre, Tiivistelmä Tämä väitöskirja käsittelee digitalisaation ja siihen liittyvien big data -teknologioiden vaikutuksia johdon laskentatoimeen. Sen tarkoitus on lisätä ymmärrystä siitä, kuinka nämä uudet määrällistämisen ja laskennan keinot kietoutuvat johdon laskentatoimen asiantuntemukseen, joka on perinteisesti luonut ja yhdistänyt laskennallisia tiloja ja laskelmia liberaaleihin hallinto-ohjelmiin. Korostamalla digitaalisen tilan performatiivisia piirteitä väitöskirja tarjoaa tuoreen tavan lähestyä ”digitaalisuutta" johdon laskentatoimen näkökulmasta. Vaikka viime aikoina tutkimus onkin lisääntynyt disruptiivisen digitaalisen muutoksen osalta, on kuitenkin vielä hyvin vähän empiiristä ja kriittistä tutkimusta tämän muutoksen mahdollisista vaikutuksista johdon laskentatoimeen sen organisatorisissa ja sosiaalisissa yhteyksissä. Tämä väitöskirja haastaa digitalisaatioon ja big data -teknologioihin liittyvän yksinkertaistetun teknisen näkemyksen ja tarkastelee aihetta kokonaisvaltaisemmin monitieteellisestä laskentatoimen näkökulmasta. Väitöskirja koostuu kolmesta toisiinsa liittyvästä esseestä, jotka yhdessä tuovat esiin laskentatoimen laskennallisten käytäntöjen välittävän ja muokkaavan roolin digitaalisessa ympäristössä. Empiiriset havainnot osoittavat ensinnäkin, kuinka data-analytiikka toimii performatiivisena moottorina, joka luo koordinaatiota ja ohjausta luovassa digitaalisessa tuotekehitysorganisaatiossa. Toiseksi havainnot osoittavat, kuinka yksilöiden jokapäiväistä elämää hallitaan ilmaiseksi ladattavien digitaalisten sovellusten markkinoilla. Kolmanneksi havainnot osoittavat, kuinka erityisillä digitaaliseen laskennalliseen tila-avaruuteen liitettävillä ominaisuuksilla näyttää olevan vaikutuksia johdon laskentatoimen rooliin laskennan asiantuntijuutena. Väitöskirja esittääkin, että big data -teknologioiden "ainutlaatuisuus" johtuu pääasiassa niiden mahdollisuudesta taloudellistaa ja hallita uusia yksilöiden elämänalueita. Näyttää kuitenkin siltä, että nämä las
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- 2023
22. The association between discoblock result and modic changes
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Korhonen, T., primary, Järvinen, J., additional, Pesälä, J., additional, Haapea, M., additional, and Niinimäki, J., additional
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- 2023
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23. Dynamic Polarization and Relaxation of 75As Nuclei in Silicon at High Magnetic Field and Low Temperature
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Järvinen, J., Ahokas, J., Sheludiakov, S., Vainio, O., Zvezdov, D., Lehtonen, L., Vlasenko, L., and Vasiliev, S.
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- 2017
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24. Dynamic Nuclear Polarization and Relaxation of H and D Atoms in Solid Mixtures of Hydrogen Isotopes
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Sheludiakov, S., Ahokas, J., Järvinen, J., Vainio, O., Lehtonen, L., Vasiliev, S., Lee, D. M., and Khmelenko, V. V.
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- 2017
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25. COUPLED FEM AND SYSTEM SIMULATOR IN THE SIMULATION OF ASYNCHRONOUS MACHINE DRIVE WITH DIRECT TORQUE CONTROL
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Kanerva, S., Stulz, C., Gerhard, B., Burzanowska, H., Järvinen, J., Seman, S., Wiak, S., editor, Dems, M., editor, and Komęza, K., editor
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- 2006
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26. Electron Spin Resonance Study of Electrons Trapped in Solid Molecular Hydrogen Films
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Sheludiakov, S., Ahokas, J., Järvinen, J., Vainio, O., Lehtonen, L., Zvezdov, D., Khmelenko, V., Lee, D. M., and Vasiliev, S.
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- 2016
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27. Understanding the concept of subjectivity in performance evaluation and its effects on perceived procedural justice across contexts
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Tran, T.-V. (Thuy-Van), Järvinen, J. (Janne), Tran, T.-V. (Thuy-Van), and Järvinen, J. (Janne)
- Abstract
This study explores the notion of subjectivity in performance evaluation as a multidimensional concept, including ex ante specified and ex post subjective evaluation, which are determined at different phases of an evaluation period. This distinction is important as these subjectivity types have different purposes and varying impacts on organisational outcomes. Based on a survey of 160 Vietnamese middle managers, we uncover their assorted impacts on perceived procedural justice across contexts of formalisation and job autonomy. As such, this study seeks to offer important insights on the literature of subjective evaluation and organisational justice.
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- 2022
28. The relationships between performance evaluation practices and fairness perceptions
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Järvinen, J. (Janne), Lepistö, S. (Sinikka), Tran, T.-V. (Thuy-Van), Järvinen, J. (Janne), Lepistö, S. (Sinikka), and Tran, T.-V. (Thuy-Van)
- Abstract
The motivation for this dissertation stems from the important roles of performance evaluation practices and the associated employee fairness perceptions. These have strong effect on numerous organizational outcomes (e.g. performance) as well as organizational members’ attitudes and behaviours (e.g. satisfaction, well-being and commitment). Although previous research has yielded many important insights on how performance evaluation practices influence employee fairness perceptions, there are still research gaps that must be filled for a comprehensive understanding on the topic. Since it is important for companies to implement performance evaluation systems that are seen as fair in the pursuit of positive outcomes at the workplace, this dissertation aims to gain an in-depth understanding of the effect of performance evaluation practices on employee perceived fairness. The dissertation consists of three interrelated articles that examine from multiple theoretical angles performance evaluation practices and their impact on employees’ perception of fairness. Emphasis is devoted to the subjective evaluation of supervisors because there are mixed findings with regard to its effectiveness and the behavioural consequences associated with it. The dissertation also explores multiple dimensions of employee fairness perception and seeks to understand the origins of fairness perception from a variety of perspectives. Further, the impacts of contextual factors are highlighted. As such, this dissertation aims to make contributions to the theory of management control and organizational justice. Moreover, focusing on Vietnam for the research context, the study responds to the need for more research on emerging economies, thereby extending the accounting literature worldwide. The findings of this dissertation have practical implications for organizations to improve their performance evaluation practices in such a way that they are deemed fair by employees., Tiivistelmä Tämä väitöskirja käsittelee suoriutumisen arviointimenetelmiä ja niihin liittyviä työntekijöiden kokemuksia oikeudenmukaisuudesta. Nämä tekijät vaikuttavat useisiin organisatorisiin tuloksiin, kuten työyhteisön asenteisiin ja käytökseen, esimerkiksi työtyytyväisyyteen, työhyvinvointiin ja työhön sitoutumiseen. Aiemmasta tutkimuksesta huolimatta suoriutumisen arviointia ja organisatorista oikeudenmukaisuutta käsittelevässä kirjallisuudessa on vielä runsaasti avoimia tutkimuskysymyksiä. Koska yrityksissä on tärkeää ottaa käyttöön suoriutumisen arviointimenetelmiä, jotka koetaan oikeudenmukaisiksi ja jotka johtavat myönteisiin tuloksiin työpaikalla, tämä väitöskirja pyrkii lisäämään ymmärrystä siitä, miten suoriutumisen arviointimenetelmät vaikuttavat työntekijöiden käsityksiin oikeudenmukaisuudesta. Väitöskirja koostuu kolmesta toisiinsa liittyvästä artikkelista, jotka käsittelevät suoriutumisen arviointimenetelmiä ja niiden vaikutuksia työntekijöiden käsityksiin oikeudenmukaisuudesta. Aihetta tarkastellaan useista teoreettisista näkökulmista käsin. Tutkimus painottuu erityisesti esimiesten antamaan subjektiiviseen arviointiin, koska aiemmat tutkimustulokset arvioinnin vaikuttavuudesta ja sen seurauksista ihmisten käyttäytymiseen ovat ristiriitaisia. Väitöskirja perehtyy monipuolisesti työntekijöiden kokemuksiin oikeudenmukaisuudesta pyrkien ymmärtämään niitä useista eri lähtökohdista tarkasteltuna. Lisäksi väitöskirjatyössä painotetaan kontekstuaalisten tekijöiden vaikutuksia. Tutkimus tuottaa lisätietoa johdon ohjausjärjestelmiä ja organisatorista oikeudenmukaisuutta käsitteleviin teorioihin. Lisäksi tämä tutkimus laajentaa laskentatoimen tutkimuskenttää globaalisti käyttämällä Vietnamia tutkimuskontekstinaan samalla vastaten tarpeeseen tuottaa lisätietoa kehittyvistä talouksista. Käytännön vaikutuksena tutkimustulokset auttavat organisaatioita parantamaan suoriutumisen arviointimenetelmistään oikeudenmukaisempia myös työntekijöiden näkökulmasta tarkaste
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- 2022
29. Enabling control in post-acquisition integration
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Järvinen, J. (Janne), Tessier, S. (Sophie), Väisänen, M. (Marjo), Järvinen, J. (Janne), Tessier, S. (Sophie), and Väisänen, M. (Marjo)
- Abstract
Successful mergers and acquisitions (M&A) require organizations implement effective management control systems across the organization and its subsidiaries. Quite often, organizations resort to a top-down integration of these control systems due to high pressure to standardize the systems across the global firm often at a fast pace. These actions are likely to induce negative responses by the new organizational members in acquired subsidiaries, as suggested also by prior literature. Drawing on the framework of enabling formalization, this dissertation enhances our understanding of management control integrations in the context of M&A. Composed of three inter-related essays, it investigates how management control systems can be perceived as enabling instead of coercive by the organizational members during post-acquisition integration. Using a qualitative, interpretive case study the research reveals new factors affecting how management control systems are perceived by the objects of control. The dissertation finds trust as an incremental factor influencing employees’ perceptions of the controls whether it concerns managerial intentions, the development process, or the daily use of the controls. It further shows how enabling control systems can support socialization of new employees during post-acquisition integration. Consequently, it explains how managers’ actions lead to enabling perceptions and how employees deal with temporary coercion with frame switching. With these theoretical contributions this dissertation moves the line of inquiry forward in the management control literature using the concept of enabling control. As for practical contributions for organizations undergoing M&A, the dissertation suggests focusing more on how to integrate people, not merely systems, by creating trustful interpersonal relationships between key persons of the parties of the M&A. Taking the time to rationalize and give support to the local subsidiaries he, Tiivistelmä Menestyäkseen yrityskaupoissa yritysten on luotava tehokkaat johdon ohjaus- ja kontrollijärjestelmät pääkonttorin ja tytäryhtiöiden välille. Näissä tilanteissa turvaudutaan usein ylhäältä alaspäin johdettuun integraatioon globaalin yhtiön järjestelmien harmonisointivaatimusten sekä aikapaineiden vuoksi. Aiempi kirjallisuus osoittaa tällaisen toiminnan aiheuttavan usein negatiivista suhtautumista ostetun yrityksen henkilöstössä. Tukeutuen mahdollistavan byrokratian viitekehykseen, tämä väitöskirja lisää ymmärrystämme ohjausjärjestelmäintegraatioiden toteuttamisesta yrityskauppatilanteissa. Kolmen toisiinsa liittyvän esseen avulla väitöskirja tutkii sitä, kuinka johdon ohjausjärjestelmät voidaan integroida niin että ostavan yrityksen henkilöstö kokisi ne mahdollistavina järjestelminä pakottavien kontrollien sijaan. Käyttäen laadullista ja tulkitsevaa tapaustutkimusotetta, tutkimus paljastaa uusia tapoja kuinka mahdollistavaa näkemystä voidaan vaalia. Tutkimus paljastaa luottamuksen olevan keskeisessä roolissa vaikuttamassa henkilöstön näkemyksiin ohjausjärjestelmistä koskien niin johdon tarkoitusperiä, järjestelmien kehitysprosesseja, kuin myös järjestelmien päivittäistä käyttöä. Lisäksi väitöskirja tuo esille, kuinka ohjausjärjestelmäintegraatiot voivat toimia tukena yrityskauppojen kohteena olevan henkilöstön sosiaalistamisessa osaksi uutta yhteisöä. Näin ollen, se tuo esiin keinoja, joita yritykset voivat hyödyntää johdon ohjausjärjestelmäintegraatioita toteuttaessaan auttaakseen ostetun yrityksen henkilöstöä sopeutumaan uuteen tilanteeseen ja näkemään järjestelmät mahdollistavina työkaluina. Tutkimus osoittaa myös, kuinka henkilöstö käsittelee väliaikaista pakottavaa näkemystä niin sanottujen raamien vaihdannan keinoin. Nämä teoreettiset tulokset lisäävät tietoa johdon ohjausjärjestelmistä ja henkilöstön suhtautumisesta niihin. Käytännön tasolla väitöskirja ottaa kantaa yrityskauppojen jälkeisiin integraatioihin suuntaamalla huomiota ihmisten integroin
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- 2022
30. Purely spatial diffusion of H atoms in solid normal- and para-hydrogen films
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Sheludiakov, S., primary, Lee, D. M., additional, Khmelenko, V. V., additional, Dmitriev, Yu. A., additional, Järvinen, J., additional, Ahokas, J., additional, and Vasiliev, S., additional
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- 2022
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31. A large octupole magnetic trap for research with atomic hydrogen
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Ahokas, J., primary, Semakin, A., additional, Järvinen, J., additional, Hanski, O., additional, Laptiyenko, A., additional, Dvornichenko, V., additional, Salonen, K., additional, Burkley, Z., additional, Crivelli, P., additional, Golovizin, A., additional, Nesvizhevsky, V., additional, Nez, F., additional, Yzombard, P., additional, Widmann, E., additional, and Vasiliev, S., additional
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- 2022
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32. Nuclear-Polarized Phases of H Atoms Embedded in Solid Molecular Hydrogen Films
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Sheludiakov, S., primary, Lee, D. M., additional, Khmelenko, V. V., additional, Ahokas, J., additional, Järvinen, J., additional, and Vasiliev, S., additional
- Published
- 2021
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33. Understanding political accountability in a strong structuration framework
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Mutiganda, J. C. (Jean Claude) and Järvinen, J. T. (Janne T.)
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Public sector ,Position-practice ,Strong structuration theory ,Accountability - Abstract
Purpose: Research was conducted to investigate whether, and how, political accountability might stabilise when agents are faced with profound changes in external structures such as competition laws and austerity policies. Design/methodology/approach: We performed a field study from 2007 to 2015 in a regional hub in Finland and worked with data from document analysis, interviews and meeting observations. We have used embedded research design, where we apply methodological bracketing as well as composite sequence analysis for field research. Findings: Accountability declined when irresistible external structures were the dominant influence on the unreflective actions of agents-in-focus. With time, however, the agents started acting critically by drawing on structures that could facilitate strategic actions to stabilise political accountability. Research limitations/implications: The field research and interpretation of the data were limited to the organisation analysed; however, the theoretical arguments allow for analytical generalisations. Practical implications: The research demonstrates how public officials and political decision-makers can eventually adopt a strategic approach when faced with irresistible change in external structures. Social implications: The research demonstrates how public officials and political decision-makers can eventually adopt a strategic approach when faced with irresistible changes in external structures. Originality/value: The study locates political accountability in the context of strong structuration theory and discusses how it is redefined by external structures.
- Published
- 2021
34. Välilevyrappeumaan liittyvät nikaman luuydinmuutokset eli Modic-muutokset ja niiden kliininen merkitys
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Määttä, J. (Juhani), Niinimäki, J. (Jaakko), Järvinen, J. (Jyri), and Karppinen, J. (Jaro)
- Abstract
Tiivistelmä Välilevyrappeumaan liittyvillä rustoisen nikamapäätelevyn alaisilla luuydinmuutoksilla eli Modic- muutoksilla on paljon yhteistä muualla elimistössä tavattavien luuydinmuutosten kanssa. Modic-muutokset näkyvät magneettikuvissa ja ne voidaan jakaa kolmeen eri tyyppiin. Muutosten tarkka syntytapa on epäselvä ja ehdotettu bakteeri-infektioteoria kiistanalainen. Erotusdiagnostisesti lannerangan luuydinmuutoksia todetaan myös spondylodiskiitin, spondylartriitin ja murtumien yhteydessä. Modic-muutoksia on hankalaa todentaa kliinisellä tutkimisella. Tulehduksellinen ja luuydinturvotusta aiheuttava tyypin 1 Modic-muutos on yhdistetty melko yhtenäisesti alaselkäkipuun. Modic-muutokset ovat kuitenkin yleisiä myös normaaliväestössä, ja selkäkipupotilaat tulisi aina tutkia yksilöllisesti ja kokonaisvaltaisesti muistaen biopsykososiaaliset tekijät. Haasteena onkin erottaa mahdollisesti kliinisesti merkittävät muutokset merkityksettömistä. Selkeitä Modic-muutosten hoitolinjoja ei toistaiseksi ole.
- Published
- 2021
35. Serum biomarkers for Modic changes in patients with chronic low back pain
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Karppinen, J. (Jaro), Koivisto, K. (Katri), Ketola, J. (Jukka), Haapea, M. (Marianne), Paananen, M. (Markus), Herzig, K. (Karl‑Heinz), Alini, M. (Mauro), Lotz, J. (Jeffrey), Dudli, S. (Stefan), Samartzis, D. (Dino), Risteli, J. (Juha), Majuri, M. (Marja‑Leena), Alenius, H. (Harri), Kyllönen, E. (Eero), Järvinen, J. (Jyri), Niinimäki, J. (Jaakko), Grad, S. (Sibylle), Karppinen, J. (Jaro), Koivisto, K. (Katri), Ketola, J. (Jukka), Haapea, M. (Marianne), Paananen, M. (Markus), Herzig, K. (Karl‑Heinz), Alini, M. (Mauro), Lotz, J. (Jeffrey), Dudli, S. (Stefan), Samartzis, D. (Dino), Risteli, J. (Juha), Majuri, M. (Marja‑Leena), Alenius, H. (Harri), Kyllönen, E. (Eero), Järvinen, J. (Jyri), Niinimäki, J. (Jaakko), and Grad, S. (Sibylle)
- Abstract
Purpose: Lumbar Modic change (MC) can serve as a diagnostic marker as well as an independent source of chronic low back pain (CLBP). This study aimed to test for the existence of serum biomarkers in CLBP patients with MC. Methods: Age- and sex-matched CLBP patients with confirmed MC on lumbar MRI (n = 40) and pain-free controls (n = 40) were assessed. MC was classified into M1, predominating M1, predominating M2 and M2. MC volumes were calculated. Fasting blood samples were assessed for inflammatory mediators, signalling molecules, growth factors and bone turnover markers. Serum concentrations of 46 biomarkers were measured. Results: Median concentrations of interleukin (IL)-15 (p < 0.001), IL-8 (p < 0.001), tumour necrosis factor (TNF)-alpha (p < 0.001), Eotaxin-1 (p < 0.05), Eotaxin-3 (p < 0.001), monocyte chemotactic protein (MCP)-1 (p < 0.05), macrophage inflammatory protein (MIP)-1alpha (p < 0.01), TEK receptor tyrosine kinase (Tie)-2 (p < 0.001), vascular cell adhesion molecule (VCAM)-1 (p < 0.001), RANTES (p < 0.001), C telopeptide of type I collagen (CTX)-1 (p < 0.001), vascular endothelial growth factor (VEGF)-C (p < 0.001), VEGF-D (p < 0.05), fms-related tyrosine kinase (Flt)-1 (p < 0.01) and intercellular adhesion molecule (ICAM)-1 (p < 0.01) were significantly higher among controls. IL-1sRII (23.2 vs. 15.5 ng/ml, p < 0.001) and hepatocyte growth factor (HGF)-1 (169 vs. 105 pg/ml, p < 0.01) concentrations were significantly higher among patients. Type or volume of MC was not associated with biomarker concentrations. Conclusions: This is the first study to assess the blood serum biomarker profile in individuals with CLBP with MC. Several biomarkers were suppressed, while two markers (IL-1sRII and HGF) were elevated among MC patients, irrespective of MC type or size, with CLBP compared with asymptomatic controls.
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- 2021
36. The relationship between subjectivity in managerial performance evaluation and the three dimensions of justice perception
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Tran, T.-V. (Thuy-Van), Lepistö, S. (Sinikka), Järvinen, J. (Janne), Tran, T.-V. (Thuy-Van), Lepistö, S. (Sinikka), and Järvinen, J. (Janne)
- Abstract
This paper examines the relationship between subjectivity in performance evaluation and the three dimensions of justice perceptions in an emerging economy; prior research on this topic has primarily focused solely on the advanced capitalist economies of Western nations. The paper also aims to expand on existing research by focusing on the role of interactional justice perceptions in relation to subjective evaluation (Byrne et al. in Hum Resour Manag J 22(2):129–147; Folger and Cropanzano, in Organizational justice and human resource management, Sage, Thousand Oaks, 1998). Results from a survey of 160 middle managers in Vietnam indicate that subjective evaluation is associated predominantly with negative effects. We found that, in an emerging economy like that of Vietnam, subjective evaluation reduces interactional justice perception, which in turn decreases the perception of procedural and distributive justice. The mediating effects suggest that the reason subjective evaluation influences employee procedural/distributive justice perceptions lies in the interactional justice perceived from supervisors. This research clarifies the effects of subjective evaluation on the dimensions of justice perception and contributes to the literature on performance evaluation and organizational justice in a non-Western context. It also highlights the importance of respect and communication for fairness perception in both theory and practice.
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- 2021
37. Fostering enabling perceptions of management controls during post‐acquisition integration
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Väisänen, M. (Marjo), Tessier, S. (Sophie), Järvinen, J. T. (Janne T.), Väisänen, M. (Marjo), Tessier, S. (Sophie), and Järvinen, J. T. (Janne T.)
- Abstract
The purpose of this paper is to increase our understanding of how enabling perceptions of new management controls (MCs) can be fostered. Prior research suggests that employees are more likely to use new MCs if they perceive them as enabling. However, rapid implementation of new MCs due to circumstances such as mergers and acquisitions can leave employees feeling coerced into using them, making it difficult to foster enabling perceptions. Based on a case study where an acquirer faces pressure to impose rigid controls on an acquired firm, we suggest factors contributing to enabling perceptions. Using interviews, observation, and document analysis, we find that positive relationships and mutual trust between the acquirer and the acquiree facilitated enabling perceptions of the MCs. We show that managers at the acquirer actively fostered trust using trust‐building activities and communicated their intentions underlying the implementation of new MCs. Doing so helped employees rationalize the controls as tools to help them do their work tasks. We also find that positive relationships reinforced by regular meetings were a way of providing assistance to employees in dealing with rigid MCs. This study contributes to the literature on enabling controls by developing a processual framework that suggests how trust can foster enabling perceptions from the intentions behind the implementation of new MCs, to their development process and daily use. In doing so, the study further develops our understanding of the relationship between enabling control and trust and helps in understanding how rigid controls can be implemented without generating mistrust.
- Published
- 2021
38. Atomic Hydrogen in Thick H2 Films at Temperatures 0.05–2 K
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Järvinen, J., Khmelenko, V. V., Lee, D. M., Ahokas, J., and Vasiliev, S.
- Published
- 2011
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39. Stabilization of H and D atoms in Aggregates of Kr Nanoclusters Immersed in Superfluid Helium
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Boltnev, R. E., Bernard, E. P., Järvinen, J., Krushinskaya, I. N., Khmelenko, V. V., and Lee, D. M.
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- 2010
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40. SQUID Measurements of the Susceptibilities of Impurity-Helium Condensates
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Järvinen, J., Paulsen, C., Bernard, E. P., Khmelenko, V. V., and Lee, D. M.
- Published
- 2008
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41. Magnetic Resonance Studies of Cold Atomic Hydrogen Gas
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Ahokas, J., Järvinen, J., and Vasiliev, S.
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- 2008
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42. Thermal Compression of Atomic Hydrogen on Helium Surface
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Järvinen, J., Ahokas, J., and Vasiliev, S.
- Published
- 2007
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43. Lumbar degenerative Modic changes:association between bone turnover and low back symptoms, and the effect of a zoledronic acid treatment intervention
- Author
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Järvinen, J. (Jyri), Niinimäki, J. (Jaakko), Tervonen, O. (Osmo), and Karppinen, J. (Jaro)
- Subjects
bone marrow ,bone turnover ,Modic-muutos ,lumbar spine ,lumelääke ,magneettikuvaus ,välilevyrappeuma ,luustokartta ,luun aineenvaihdunta ,lanneranka ,luuydin ,zoledronic acid ,alaselkäkipu ,disc degeneration ,placebo ,magnetic resonance imaging ,bone scintigraphy ,Modic changes ,low back symptoms ,tsoledronihappo - Abstract
Lumbar degenerative bone marrow changes, Modic changes (MC), are visible in the bone marrow adjacent to the degenerated intervertebral discs in magnetic resonance imaging (MRI). MC are categorized into three types: Type 1 (MC1) appears as inflamed bone marrow and is composed mainly of fibrovascular tissue proliferation, Type 2 (MC2) appears as fat and is composed of yellow fat replacement, and Type 3 (MC3) appears as dense bone and is composed of highly mineralized, sclerotic bone marrow. This thesis investigated the associations of MC with bone turnover in bone scintigraphy and with prospective low back symptoms, and the treatment response of MC to a single intravenous infusion of zoledronic acid (ZA), an osteoporosis drug. Bone scintigraphy is a method of nuclear imaging which shows active bone turnover as increased tracer uptake in the skeleton. Patients who had undergone lumbar MRI and bone scintigraphy within six months of each other in 2007–2008 were included in the study. Bone turnover was increased in the area of MC1 more often than in other MC types. This reflects the inflammatory nature of MC1 and is consistent with increased vascularity and bone turnover. Patients with MC and low back symptoms were followed for over a two-year period. MC1 was associated with pain intensity and disability, whereas the same correlation was not found for MC2. In a randomized controlled trial, the effect of ZA on MC was compared with that of intravenous saline. MRI was examined at baseline and approximately 12 months after the infusion. A trend of MC1 converting to MC2, and a reduction in the volume of MC1 was noted as a result of ZA. In conclusion, MC1 is more consistently associated with increased bone turnover and low back symptoms than other MC types. ZA may offer an alternative treatment for MC1. However, more research must be conducted to confirm the benefits of ZA. Tiivistelmä Selkärangan välilevyrappeumaan liittyvät selkänikamien luuydinmuutokset näkyvät magneettikuvauksessa (MK) ja niitä kutsutaan Modic-muutoksiksi. Modic-muutokset jaetaan kolmeen tyyppiin: tyyppi 1 (MC1) on tulehduksellisen näköinen ja sisältää korostunutta verisuonitusta ja luuturvotusta, tyyppi 2 (MC2) sisältää rasvoittunutta luuydintä ja tyyppi 3 (MC3) sisältää mineraalipitoisuudeltaan korostunutta, skleroottista luuydintä. Tämä väitöskirjatutkimus sisältää kolme osatyötä, joissa on tutkittu Modic-muutosten yhteyttä luun aineenvaihduntaan luustokartassa, yhteyttä kipuun ja toimintakyvyn laskuun kahden vuoden seurantatutkimuksessa sekä hoitovastetta suonensisäiseen kerta-annoshoitoon tsoledronihapolla. Luustokartta on isotooppitutkimuksen muoto, joka osoittaa kiihtyneen luun aineenvaihdunnan korostuneena merkkiainekertymänä. Tutkimusotoksen potilailta oli kuvattu alaselän MK ja luustokartta 6kk sisällä toisistaan vuosina 2007–2008. Tutkimuksessa havaittiin MC1:n alueella muita Modic-tyyppejä useammin kiihtynyttä luun aineenvaihduntaa, joka sopii muutoksen tulehdukselliseen ilmiasuun ja kudosnäytteissä aiemmin todettuun verisuonituksen lisääntymiseen. Kahden vuoden seurantatutkimuksessa potilailla oli alaselkäoireita ja Modic-muutoksia. Tutkimuksessa havaittiin MC1:n olevan yhteydessä alaselkäkipuun ja toimintakyvyn laskuun, kun taas vastaavaa yhteyttä ei todettu MC2:n suhteen. Satunnaistetussa kaksoissokkotutkimuksessa verrattiin tsoledronihappoa lumelääkkeeseen Modic-muutosten hoidossa alaselkäkipuisilla potilailla. 12 kuukautta kerta-annoshoidon jälkeen tehdyssä MK:ssa todettiin tsoledronihapporyhmässä MC1:n muuttumista MC2:n suuntaan ja MC1:n tilavuuden pienentymistä, mutta muutokset eivät olleet tilastollisesti merkitseviä. Tutkimusten yhteenvetona voidaan todeta, että MC1 liittyy muita MC- tyyppejä useammin kiihtyneeseen luun aineenvaihduntaan ja alaselkäoireisiin. Tsoledronihappo saattaa tarjota hoitovaihtoehdon MC1:lle, mutta tämän vahvistaminen vaatii lisää laadukkaita tutkimuksia tulevaisuudessa.
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- 2020
44. Just look at the numbers:a case study on quantification in corporate environmental disclosures
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Järvinen, J. T. (Janne T.), Laine, M. (Matias), Hyvönen, T. (Timo), and Kantola, H. (Hannele)
- Abstract
This paper sheds further light on the role of quantification in corporate environmental disclosures. Quantification is an inherently social practice, which has attracted a fair amount of academic interest in recent years. At the same time, in the field of social and environmental accounting there is a paucity of research on quantification or the role it plays for organisations, for organisational communication and in societies more broadly. Accordingly, in this paper, we will draw on a qualitative case study to discuss the potential implications that might arise from the use of quantified information in corporate environmental disclosures. Our case study illustrates the diverse effects of quantification suggested in the prior literature by placing them in the context of corporate environmental disclosures. We discuss how quantification implies fake precisionism and promotes commensuration of incomparables, thereby limiting the discussion to themes and questions preferred by company management. We maintain that quantification, while appearing to produce neutral and value-free information, has a substantive ethical dimension through how it implicates accountability relationships as well as the respective power relations between diverse stakeholders in societies.
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- 2020
45. Lumbar degenerative Modic changes:association between bone turnover and low back symptoms, and the effect of a zoledronic acid treatment intervention
- Author
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Niinimäki, J. (Jaakko), Tervonen, O. (Osmo), Karppinen, J. (Jaro), Järvinen, J. (Jyri), Niinimäki, J. (Jaakko), Tervonen, O. (Osmo), Karppinen, J. (Jaro), and Järvinen, J. (Jyri)
- Abstract
Lumbar degenerative bone marrow changes, Modic changes (MC), are visible in the bone marrow adjacent to the degenerated intervertebral discs in magnetic resonance imaging (MRI). MC are categorized into three types: Type 1 (MC1) appears as inflamed bone marrow and is composed mainly of fibrovascular tissue proliferation, Type 2 (MC2) appears as fat and is composed of yellow fat replacement, and Type 3 (MC3) appears as dense bone and is composed of highly mineralized, sclerotic bone marrow. This thesis investigated the associations of MC with bone turnover in bone scintigraphy and with prospective low back symptoms, and the treatment response of MC to a single intravenous infusion of zoledronic acid (ZA), an osteoporosis drug. Bone scintigraphy is a method of nuclear imaging which shows active bone turnover as increased tracer uptake in the skeleton. Patients who had undergone lumbar MRI and bone scintigraphy within six months of each other in 2007–2008 were included in the study. Bone turnover was increased in the area of MC1 more often than in other MC types. This reflects the inflammatory nature of MC1 and is consistent with increased vascularity and bone turnover. Patients with MC and low back symptoms were followed for over a two-year period. MC1 was associated with pain intensity and disability, whereas the same correlation was not found for MC2. In a randomized controlled trial, the effect of ZA on MC was compared with that of intravenous saline. MRI was examined at baseline and approximately 12 months after the infusion. A trend of MC1 converting to MC2, and a reduction in the volume of MC1 was noted as a result of ZA. In conclusion, MC1 is more consistently associated with increased bone turnover and low back symptoms than other MC types. ZA may offer an alternative treatment for MC1. However, more research must be conducted to confirm the benefits of ZA., Tiivistelmä Selkärangan välilevyrappeumaan liittyvät selkänikamien luuydinmuutokset näkyvät magneettikuvauksessa (MK) ja niitä kutsutaan Modic-muutoksiksi. Modic-muutokset jaetaan kolmeen tyyppiin: tyyppi 1 (MC1) on tulehduksellisen näköinen ja sisältää korostunutta verisuonitusta ja luuturvotusta, tyyppi 2 (MC2) sisältää rasvoittunutta luuydintä ja tyyppi 3 (MC3) sisältää mineraalipitoisuudeltaan korostunutta, skleroottista luuydintä. Tämä väitöskirjatutkimus sisältää kolme osatyötä, joissa on tutkittu Modic-muutosten yhteyttä luun aineenvaihduntaan luustokartassa, yhteyttä kipuun ja toimintakyvyn laskuun kahden vuoden seurantatutkimuksessa sekä hoitovastetta suonensisäiseen kerta-annoshoitoon tsoledronihapolla. Luustokartta on isotooppitutkimuksen muoto, joka osoittaa kiihtyneen luun aineenvaihdunnan korostuneena merkkiainekertymänä. Tutkimusotoksen potilailta oli kuvattu alaselän MK ja luustokartta 6kk sisällä toisistaan vuosina 2007–2008. Tutkimuksessa havaittiin MC1:n alueella muita Modic-tyyppejä useammin kiihtynyttä luun aineenvaihduntaa, joka sopii muutoksen tulehdukselliseen ilmiasuun ja kudosnäytteissä aiemmin todettuun verisuonituksen lisääntymiseen. Kahden vuoden seurantatutkimuksessa potilailla oli alaselkäoireita ja Modic-muutoksia. Tutkimuksessa havaittiin MC1:n olevan yhteydessä alaselkäkipuun ja toimintakyvyn laskuun, kun taas vastaavaa yhteyttä ei todettu MC2:n suhteen. Satunnaistetussa kaksoissokkotutkimuksessa verrattiin tsoledronihappoa lumelääkkeeseen Modic-muutosten hoidossa alaselkäkipuisilla potilailla. 12 kuukautta kerta-annoshoidon jälkeen tehdyssä MK:ssa todettiin tsoledronihapporyhmässä MC1:n muuttumista MC2:n suuntaan ja MC1:n tilavuuden pienentymistä, mutta muutokset eivät olleet tilastollisesti merkitseviä. Tutkimusten yhteenvetona voidaan todeta, että MC1 liittyy muita MC- tyyppejä useammin kiihtyneeseen luun aineenvaihduntaan ja alaselkäoireisiin. Tsoledronihappo saattaa tarjota hoitovaihtoehdon MC1:lle, mutta tämän vahvistaminen va
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- 2020
46. Does bone scintigraphy show Modic changes associated with increased bone turnover?
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Järvinen, J. (Jyri), Niinimäki, J. (Jaakko), Karppinen, J. (Jaro), Takalo, R. (Reijo), Haapea, M. (Marianne), Tervonen, O. (Osmo), Järvinen, J. (Jyri), Niinimäki, J. (Jaakko), Karppinen, J. (Jaro), Takalo, R. (Reijo), Haapea, M. (Marianne), and Tervonen, O. (Osmo)
- Abstract
Purpose: Our purpose was to evaluate whether Modic changes (MC) revealed in lumbar MRI are associated with increased tracer uptake shown in bone scintigraphy. To our knowledge, this has not previously been studied. Methods: We included patients with MC shown in lumbar MRI and bone scintigraphy performed within six months before or after MRI. Exclusion criteria included metastasis and other specific lesions in the area of interest such as discitis, tumors or fractures. We compared the level and type of MC to the degree of tracer uptake shown in bone scintigraphy. Tracer uptake was assessed both visually and quantitatively. We calculated the lesion-to-normal-bone ratios between the MC area with increased tracer uptake and the vertebra with normal tracer uptake. We used linear mixed models in statistical analyses. Results: Our study sample consisted of 93 patients (aged 37–86) with 299 MC (28 Type 1 (M1), 50 mixed Type 1/2 (M1/2), 3 mixed Type 1/3 (M1/3), 211 Type 2 (M2), 6 mixed Type 2/3 (M2/3), and 1 Type 3 (M3)). Of all the MC, 26 (93 %) M1, 34 (64 %) in the combined M1/2 and M1/3 group, and 11 (5 %) in the combined M2, M2/3 and M3 group showed increased tracer uptake. The mean lesion-to-normal-bone ratio was higher for lesions with a Type 1 component (M1, M1/2 and M1/3) than for other types, at 1.55 (SD 0.16) for M1; 1.44 (SD 0.21) for combined M1/2 and M1/3; and 1.28 (SD 0.11) for combined M2, M2/3 and M3; p = 0.001). Conclusion: In most cases, MC with a Type 1 component showed increased tracer uptake in bone scintigraphy. This indicates that bone turnover is accelerated in the M1 area.
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- 2020
47. The Effect of Zoledronic Acid on Serum Biomarkers among Patients with Chronic Low Back Pain and Modic Changes in Lumbar Magnetic Resonance Imaging
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Koivisto, K. (Katri), Karppinen, J. (Jaro), Marianne Haapea, M. H. (Marianne Haapea), Järvinen, J. (Jyri), Kyllönen, E. (Eero), Tervonen, O. (Osmo), Niinimäki, J. (Jaakko), Alini, M. (Mauro), Lotz, J. (Jeffrey), Dudli, S. (Stefan), Samartzis, D. (Dino), Risteli, J. (Juha), Majuri, M.-L. (Marja-Leena), Alenius, H. (Harri), Grad, S. (Sibylle), University of Zurich, and Koivisto, Katri
- Subjects
Modic change ,serum biomarkers ,Pain Research ,Clinical Trials and Supportive Activities ,10051 Rheumatology Clinic and Institute of Physical Medicine ,Evaluation of treatments and therapeutic interventions ,610 Medicine & health ,1308 Clinical Biochemistry ,serum biomarkersm magnetic resonance imaging ,zoledronic acid ,Clinical Research ,6.1 Pharmaceuticals ,Musculoskeletal ,chronic low back pain ,randomized trial ,magnetic resonance imaging ,Chronic Pain - Abstract
The aim of the current study was to compare changes in serum biomarkers, including inflammatory mediators, signaling molecules, growth factors and markers of bone turnover after a single intravenous infusion of 5 mg zoledronic acid (ZA, a long-acting bisphosphonate; n = 20) or placebo (n = 20) among patients with Modic changes (MC) and chronic low back pain in a randomized controlled design. The MCs were classified into M1, predominating M1, predominating M2, and M2. We measured the serum concentrations of 39 biomarkers at baseline, and one month and one year after treatment. After Benjamini–Hochberg (B–H) correction, we observed significant differences in three biomarkers over one year: Interferon-γ-inducible protein (IP-10) had risen in the ZA group (p = 0.005), whereas alkaline phosphatase (AFOS) and intact procollagen I N-terminal propeptide (iPINP) had significantly decreased in the ZA group, but had not changed in the placebo group (p < 0.001 for both). Change in iPINP correlated with change in the volume of all MC and M1 lesions. ZA downregulated bone turnover markers as expected and, surprisingly, increased the chemokine IP-10 relative to placebo treatment. This adds to our knowledge of the effects of ZA on MC and the biomarkers that signal this process.
- Published
- 2019
48. Experimental cell with a Fabry–Pérot resonator tuned in situ for magnetic resonance studies of matrix-isolated radicals at temperatures below 1 K
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Sheludiakov, S., primary, Lee, D. M., additional, Khmelenko, V. V., additional, Järvinen, J., additional, Ahokas, J., additional, and Vasiliev, S., additional
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- 2020
- Full Text
- View/download PDF
49. Searching for magnetostatic modes in spin-polarized atomic hydrogen
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Lehtonen, L, primary, Vainio, O, additional, Ahokas, J, additional, Järvinen, J, additional, Sheludyakov, S, additional, Suominen, K-A, additional, and Vasiliev, S, additional
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- 2020
- Full Text
- View/download PDF
50. Studies of nuclear polarization of hydrogen atoms embedded in solid molecular hydrogen and hydrogen deuteride films
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Sheludiakov, S., primary, Lee, D. M., additional, Khmelenko, V. V., additional, Ahokas, J., additional, Järvinen, J., additional, and Vasiliev, S., additional
- Published
- 2020
- Full Text
- View/download PDF
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