Hornerin deposits in neuronal intranuclear inclusion disease : direct identification of proteins with compositionally biased regions in inclusions

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disorder, characterized by the presence of eosinophilic inclusions (NIIs) within nuclei of central and peripheral nervous system cells. This study aims to identify the components of NIIs, which have been difficult to analyze directly due to their insolubility. In order to establish a method to directly identify the components of NIIs, we first analyzed the huntingtin inclusion-rich fraction obtained from the brains of Huntington disease model mice. Although the sequence with expanded polyglutamine could not be identified by liquid-chromatography mass spectrometry, amino acid analysis revealed that glutamine of the huntingtin inclusion-rich fraction increased significantly. This is compatible with the calculated amino acid content of the transgene product. Therefore, we applied this method to analyze the NIIs of diseased human brains, which may have proteins with compositionally biased regions, and identified a serine-rich protein called hornerin. Since the analyzed NII-rich fraction was also serine-rich, we suggested hornerin as a major component of the NIIs. A specific distribution of hornerin in NIID was also investigated by Matrix-assisted laser desorption/ionization imaging mass spectrometry and immunofluorescence. Finally, we confirmed a variant of hornerin by whole-exome sequencing and DNA sequencing. This study suggests that hornerin may be related to the pathological process of this NIID, and the direct analysis of NIIs, especially by amino acid analysis using the NII-rich fractions, would contribute to a deeper understanding of the disease pathogenesis.Peer reviewe

Shielding Effect on Flux Trapping in Pulsed-Field Magnetizing for Mg-B Bulk Magnet

International audienceMg-B superconducting bulk materials are characterized as simple and uniform metallic compounds, and capable of trapping homogeneous field with beautiful conical shapes. Although pulsed-field magnetization technique (PFM) is expected as a cheap and an easy way to activate them, the heat generation due to magnetic flux motion in bulk magnets causes serious degradation of captured fields. It is important to suppress the flux motions during PFM to decrease the heat generation. In this study, authors precisely estimated the flux trapping to the bulk samples, found that the flux-shielding effect related to the sample dimensions. Moreover, the Ti-addition to the bulk sample affected the frequency of flux jump happenings. The magnetic field capturing of 5.0wt%Ti-added samples reached the highest value of 0.76 T, while the starting point of magnetic field invasion into the sample centre shifted from 1.0 T to 1.2 T with increasing sample thickness from 3.67 mm to 5.80 mm. The occurrence of flux jumps was suppressed in 5.0wt%Ti-dopped sample, which means that the heat capacity of the compounds shifted with varying Ti addition, effectively prevented the flux jumps

Shielding Effect on Flux Trapping in Pulsed-Field Magnetizing for Mg-B Bulk Magnet

International audienceMgB2 superconducting bulk materials are characterized as simple and uniform metallic compounds, and capable of trapping field of non-distorted conical shapes. Although pulsed-field magnetization technique (PFM) is expected to be a cheap and an easy way to activate them, the heat generation due to the magnetic flux motion causes serious degradation of captured fields. The authors precisely estimated the flux trapping property of the bulk samples, found that the flux-shielding effect closely attributed to the sample dimensions. The magnetic field capturing of Ti-5.0wt% sample reached the highest value of 0.76 T. The applied field which reached the centre of the sample surface shifted from 1.0 T to 1.2 T with increasing sample thickness from 3.67 mm to 5.80 mm. This means that the shielding effect was enhanced with increasing the sample thickness. Moreover, Ti-addition affected the frequency of flux jump happenings. The occurrence of flux jumps was suppressed in 5.0wt%Ti-added sample. This means that the heat capacity of the compounds was promoted by Ti addition

Shielding Effect on Flux Trapping in Pulsed-Field Magnetizing for Mg-B Bulk Magnet

International audienceMg-B superconducting bulk materials are characterized as simple and uniform metallic compounds, and capable of trapping homogeneous field with beautiful conical shapes. Although pulsed-field magnetization technique (PFM) is expected as a cheap and an easy way to activate them, the heat generation due to magnetic flux motion in bulk magnets causes serious degradation of captured fields. It is important to suppress the flux motions during PFM to decrease the heat generation. In this study, authors precisely estimated the flux trapping to the bulk samples, found that the flux-shielding effect related to the sample dimensions. Moreover, the Ti-addition to the bulk sample affected the frequency of flux jump happenings. The magnetic field capturing of 5.0wt%Ti-added samples reached the highest value of 0.76 T, while the starting point of magnetic field invasion into the sample centre shifted from 1.0 T to 1.2 T with increasing sample thickness from 3.67 mm to 5.80 mm. The occurrence of flux jumps was suppressed in 5.0wt%Ti-dopped sample, which means that the heat capacity of the compounds shifted with varying Ti addition, effectively prevented the flux jumps

Study on Magnetic Flux Dissipation and Field-Trapping Performance of HTS Bulk-Shaped Magnesium Diboride in Pulse-Field Magnetizing Processes

International audienceThe magnetic flux dissipation from the MgB 2 bulk magnets during pulsed field magnetization (PFM) processes has been estimated for the samples fabricated by hot-pressing (HP) and spark plasma sintering (SPS). We defined the parameters as field penetration ratio B P /B a and the field trapping ratio B T /B P to evaluate the flux motion and performance. The data plots of trapping ratio B T /B P showed us two regions which originate from the fast flux flow and flux jump. The field trapping performance was drastically degraded when the flux jump happened. Flux jump happened at various times after the peak field. A very late flux jump happened at 420 ms which severely degraded the trapped field. This time delay, much larger than the heat propagation time in the MgB 2 sample, remains to be explained

Study on Magnetic Flux Dissipation and Field-Trapping Performance of HTS Bulk-Shaped Magnesium Diboride in Pulse-Field Magnetizing Processes

International audienceThe magnetic flux dissipation from the MgB 2 bulk magnets during pulsed field magnetization (PFM) processes has been estimated for the samples fabricated by hot-pressing (HP) and spark plasma sintering (SPS). We defined the parameters as field penetration ratio B P /B a and the field trapping ratio B T /B P to evaluate the flux motion and performance. The data plots of trapping ratio B T /B P showed us two regions which originate from the fast flux flow and flux jump. The field trapping performance was drastically degraded when the flux jump happened. Flux jump happened at various times after the peak field. A very late flux jump happened at 420 ms which severely degraded the trapped field. This time delay, much larger than the heat propagation time in the MgB 2 sample, remains to be explained

Experimental Study on Flux Trapping and Flux Jump on Pulsed-Field Magnetization Process for Mg-B Trapped-Field Magnet

Invited talkInternational audienceMgB2 bulk materials used as quasi permanent magnets are characterized as its uniform field trapping property originated homogeneous microstructure of simple metallic compound. Beautiful conical shape of trapped field distribution would suggest us to utilize it to compact and stable magnets for practical industries. The only and crucial drawback is its thermal instability which causes sudden dissipation of trapped flux called “flux jump”, which is attributed to the poor specific heat of the material which would be utilized at low temperature less than 20 K. The authors carried on the successive PFM experiments with use of 15 K cryocooler, and precisely investigated various flux jump phenomena in detail. The motions of flux invasion are classified as three modes called “no flux flow (NFF)”, “fast flux flow (FFF)”, and “flux jump (FJ)” regions. The authors clarified that the introduction of metallic inclusion by adding Ti are effective to expand the NFF region to high applied field and to prevent the flux jump to happen