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Acta Geodaetica et Geophysica Hungarica
Authors:
P. Bencze
,
B. Heilig
,
B. Zieger
,
J. Szendrői
,
J. Verő
,
H. Lühr
,
K. Yumoto
,
Y. Tanaka
, and
J. Střeštík

The total solar eclipse of August 11, 1999 offered a unique opportunity for the study of its geomagnetic effect — more specifically, of its effect on geomagnetic (Pc3) pulsations, as it swept through Europes many observatories, and additional temporary stations have also been established by Japanese, German and Hungarian groups. The present paper starts with an analysis of the ionospheric-interplanetary background. In the interplanetary medium, no indication was found which could result in any extraordinary event in pulsation activity. The both horizontally and vertically widespread ionospheric effect (electron density decrease) explains a change of the polarisation angle by about ten degrees in the local field line resonance (FLR) band. However, the most significant solar eclipse effect was identified as dramatic clockwise rotation (up to 70 degrees) of the polarisation ellipse of Pc3, Pc4 and Pc5 pulsations. Pulsation data exhibit a strong amplitude decrease (roughly by a factor of two) in and around the totality spot of the eclipse. The decrease is most significant at the local field line resonance (FLR) period. In the actual case, the FLR decrease swept over Europe with a speed being similar to the speed of the dark spot. We suppose that the FLR mechanism was disturbed by the change of particle distribution along the field lines ending in the dark zone due to upward propagation of the electron density decrease caused by the lack of ionising solar radiation in the E-layer of the ionosphere. Thus, the FLR mechanism can be disturbed both from outside, by a sudden change of the interplanetary magnetic field (Verő et al. 1998) and from inside, by a change of the particle density/distribution along the actual field line.

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Acta Physiologica Hungarica
Authors:
Gábor Skaliczki
,
M. Weszl
,
K. Schandl
,
T. Major
,
M. Kovács
,
J. Skaliczki
,
H. Redl
,
M. Szendrői
,
K. Szigeti
,
D. Máté
,
Cs Dobó-Nagy
, and
Zs Lacza

Purpose: The clinical demand for bone grafting materials necessitated the development of animal models. Critical size defect model has been criticized recently, mainly for its inaccuracy. Our objective was to develop a dependable animal model that would provide compromised bone healing, and would allow the investigation of bone substitutes. Methods: In the first group a critical size defect was created in the femur of adult male Wistar rats, and a non-critical defect in the remaining animals (Groups II, III and IV). The defect was left empty in group II, while in groups III and IV a spacer was interposed into the gap. Osteoblast activity was evaluated by NanoSPECT/CT imaging system. New bone formation and assessment of a union or non-union was observed by μCT and histology. Results: The interposition model proved to be highly reproducible and provided a bone defect with compromised bone healing. Significant bone regeneration processes were observed four weeks after removal of the spacer. Conclusion: Our results have shown that when early bone healing is inhibited by the physical interposition of a spacer, the regeneration process is compromised for a further 4 weeks and results in a bone defect during the time-course of the study.

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