Generation of Alfven Waves by Magnetic Reconnection

In this paper, results of 2.5-dimensional magnetohydrodynamical simulations are reported for the magnetic reconnection of non-perfectly antiparallel magnetic fields. The magnetic field has a component perpendicular to the computational plane, that is, guide field. The angle theta between magnetic field lines in two half regions is a key parameter in our simulations whereas the initial distribution of the plasma is assumed to be simple; density and pressure are uniform except for the current sheet region. Alfven waves are generated at the reconnection point and propagate along the reconnected field line. The energy fluxes of the Alfven waves and magneto-acoustic waves (slow mode and fast mode) generated by the magnetic reconnection are measured. Each flux shows the similar time evolution independent of theta. The percentage of the energies (time integral of energy fluxes) carried by the Alfven waves and magneto-acoustic waves to the released magnetic energy are calculated. The Alfven waves carry 38.9%, 36.0%, and 29.5% of the released magnetic energy at the maximum (theta=80^\circ) in the case of beta=0.1, 1, and 20 respectively, where beta is the plasma beta (the ratio of gas pressure to magnetic pressure). The magneto-acoustic waves carry 16.2% (theta=70^\circ), 25.9% (theta=60^\circ), and 75.0% (theta=180^\circ) of the energy at the maximum. Implications of these results for solar coronal heating and acceleration of high-speed solar wind are discussed.Comment: Accepted for publication in PASJ. 24 pages, 11 figure

Trans-activation of the human SOX3 promoter by MAZ in NT2/D1 cells

U ovom radu proučavana je uloga tri visoko konzervisana potencijalna mesta vezivanja za "Myc-associated zinc finger protein" (MAZ) u regulaciji ekspresije humanog SOX3 gena. Eseji izmenjene elektroforetske pokretljivosti u prisustvu antitela na MAZ ukazuju da kompleksi koji se formiraju na dva od tri proučavana mesta u okviru SOX3 promotora sadrže MAZ protein. Takođe, u eksperimentima kotransfekcije smo pokazali da MAZ ima ulogu pozitivnog regulatora transkripcije SOX3 gena, kako u nediferenciranim, tako i u diferenciranim NT2/D1 ćelijama. Iako je MAZ povećao i bazalnu i retinoičnom kiselinom indukovanu promotorsku aktivnost, naši rezultati ukazuju da ovaj transkripcioni faktor ne doprinosi inducibilnosti SOX3 promotora tokom neuralne diferencijacije u prisustvu retinoične kiseline.In this study, we examine the role of three highly conserved putative binding sites for Myc-associated zinc finger protein (MAZ) in regulation of the human SOX3 gene expression. Electrophoretic mobility shift and supershift assays indicate that complexes formed at two out of three MAZ sites of the human SOX3 promoter involve ubiquitously expressed MAZ protein. Furthermore, in cotransfection experiments we demonstrate that MAZ acts as a positive regulator of SOX3 gene transcription in both undifferentiated and RA-differentiated NT2/D1 cells. Although MAZ increased both basal and RA-induced promoter activity, our results suggest that MAZ does not contribute to RA inducibility of the SOX3 promoter during neuronal differentiation of NT2/D1 cells

Brain Alterations and Mini-Mental State Examination in Patients with Progressive Supranuclear Palsy: Voxel-Based Investigations Using 18F-Fluorodeoxyglucose Positron Emission Tomography and Magnetic Resonance Imaging

Background/Aims: The aim of this study was to compare differences in morphological and functional changes in brain regions in individual patients with progressive supranuclear palsy (PSP) and correlate their Mini-Mental State Examination (MMSE) score with anatomy and function using magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). Methods: Sixteen PSP patients and 20 age-matched healthy volunteers underwent FDG-PET and 3-dimensional MRI. Gray matter, white matter and metabolic activity were compared between patients and normal controls. In addition, possible correlations between the MMSE score and brain function/anatomy were examined. Results: The PSP group had reduced cerebral glucose metabolism, and lower gray and white matter volumes in the frontal lobes and midbrain compared with normal controls. In PSP subjects, the metabolic changes observed in the PET scans were greater than the loss in gray and white matter observed in the MRI scans. The MMSE scores were positively correlated with volume and FDG uptake in the frontal lobe. Conclusion: FDG-PET is a more effective tool in the diagnosis of PSP than MRI. Atrophy and hypometabolism in the frontal lobe are as important as in the basal midbrain for differentiating PSP patients who primarily exhibit cognitive dysfunction from normal controls

Suppression of cell cycle progression by Jun dimerization protein (JDP2) involves down-regulation of cyclin A2

We report here a novel role for Jun dimerization protein-2 (JDP2) as a regulator of the progression of normal cells through the cell cycle. To determine the role of JDP2 in vivo, we generated Jdp2 knock-out (Jdp2KO) mice by targeting exon 1 to disrupt the site of initiation of transcription. The healing of wounded skin of Jdp2KO mice proceeded more rapidly than that of control mice and more proliferating cells were found at wound margins. Fibroblasts derived from embryos of Jdp2KO mice proliferated more rapidly and formed more colonies than wild-type fibroblasts. JDP2 was recruited to the promoter of the gene for cyclin A2 (ccna2) at a previously unidentified AP-1 site. Cells lacking Jdp2 had elevated levels of cyclin A2 mRNA. Moreover, reintroduction of JDP2 resulted in repression of transcription of ccna2 and of cell cycle progression. Thus, transcription of the gene for cyclin A2 appears to be a direct target of JDP2 in the suppression of cell proliferation

Characteristics of Anemone Active Regions Appearing in Coronal Holes Observed with {\it Yohkoh} Soft X-ray Telescope

Coronal structure of active regions appearing in coronal holes is studied by using the data obtained with the Soft X-Ray Telescope (SXT) aboard {\it Yohkoh} from 1991 November to 1993 March. The following characteristics are found; Many of active regions appearing in coronal holes show a structure that looks like a ``sea-anemone''. Such active regions are called {\it anemone ARs}. About one-forth of all active regions that were observed with SXT from their births showed the anemone structure. For almost all the anemone ARs, the order of magnetic polarities is consistent with the Hale-Nicholson's polarity law. These anemone ARs also showed more or less east-west asymmetry in X-ray intensity distribution, such that the following (eastern) part of the ARs is brighter than its preceding (western) part. This, as well as the anemone shape itself, is consistent with the magnetic polarity distribution around the anemone ARs. These observations also suggest that an active region appearing in coronal holes has simpler (less sheared) and more preceding-spot-dominant magnetic structure than those appearing in other regions.Comment: 11 pages, 3 tables, 4 figure

Identification of mouse Jun dimerization protein 2 as a novel repressor of ATF-211The nucleotide sequence reported herein has been deposited in the DDBJ, EMBL and GenBank databanks under the accession number AB034697.

AbstractA mouse cDNA that encodes a DNA-binding protein was identified by yeast two-hybrid screening, using activating transcription factor-2 (ATF-2) as the bait. The protein contained a bZIP (basic amino acid-leucine zipper region) domain and its amino acid sequence was almost identical to that of rat Jun dimerization protein 2 (JDP2). Mouse JDP2 interacted with ATF-2 both in vitro and in vivo via its bZIP domain. It was encoded by a single gene and various transcripts were expressed in all tested tissues of adult mice, as well as in embryos, albeit at different levels in various tissues. Furthermore, mouse JDP2 bound to the cAMP-response element (CRE) as a homodimer or as a heterodimer with ATF-2, and repressed CRE-dependent transcription that was mediated by ATF-2. JDP2 was identified as a novel repressor protein that affects ATF-2-mediated transcription