Proceedings of the Japan Academy, Series B

Ion Cyclotron Waves Generated by the Entry of Solar Wind Plasma into the Magnetospheric Boundary Layer

Yoshio KATO, Yutaka TONEGAWA

1991 Volume 67 Issue 6 Pages 93-97
Published: 1991
Released on J-STAGE: October 13, 2006

DOIhttps://doi.org/10.2183/pjab.67.93

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Characteristics of ULF waves in the frequency range of pc 1 have been examined by using data obtained from induction magnetometers at conjugate stations near L=6. The ULF waves are frequently observed in magnetically quiet conditions with a good conjugaty. It is clearly shown in the dynamic spectra that the waves are gradually generated and the wave frequencies are successively changed in process of the local time. We discuss the generation mechanism of these quiet-time ULF waves comparing with ion cyclotron waves which are associated with sudden commencements of magnetic storms (ssc's) and the following initial phases. It will be concluded that even the bounda ry layer is asteady state, there are two-stream instabilities of ambient plasmas with impinging solar plasma, and that the instabilities generate ion cyclotron waves propagating to the high latitude stations along the field line.

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Isolation and Structure of Diapause Hormone of the Silkworm, Bombyx mori

Kunio IMAI, Takamichi KONNO, Yoshitaka NAKAZAWA, Takashi KOMIYA, Minor ...

1991 Volume 67 Issue 6 Pages 98-101
Published: 1991
Released on J-STAGE: October 13, 2006

DOIhttps://doi.org/10.2183/pjab.67.98

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The embryonic diapause of the silkworm, Bombyx mori is induced by a neuropeptide hormone, diapause hormone, which is secreted from the suboesophageal ganglion. About 55, 000 complexes of the suboesophageal ganglion and the first thoracic ganglion were dissected out from day 1 pupae of silkworms. The hormone was extracted with hot water and purified by a reverse-phase high performance liquid chromatography on a TSK gel octadecyl-4PW column. The second chromatography gave a single symmetric peak and the isolated hormone induced diapause in 20% eggs at a dose of 1.5ng/pupa. Diapause hormone has 24 amino acid residues and a molecular weight of 2645. The synthesized peptide with a carboxyl terminal as amide form exhibited the same behavior on HPLC and similar activity as the natural hormone.

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Sequence Variation of Human Platelet Membrane Glycoprotein IIIa Associated with the Yuk^a/Yuk^b Alloantigen System

Li WANG, Takeo JUJI, Yoichi SHIBATA, Shoji KUWATA, Katsushi TOKUNAGA

1991 Volume 67 Issue 6 Pages 102-106
Published: 1991
Released on J-STAGE: October 13, 2006

DOIhttps://doi.org/10.2183/pjab.67.102

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The human platelet alloantigens play a prominent role in provoking neonatal alloimmune thrombocytopenic purpura. The frequencies of Yuk^a and Yuk^b antigens are 1.7% and 99.9% in the Japanese population, respectively. The Yuk alloantigen system is localized on the human platelet membrane glycoprotein (GP)IIIa. To investigate the molecular structure of Yuk alloantigenic determinants, we amplified GP IIIa cDNAs from Yuk^a/a and Yuk^b/b homozygous individuals. A single nucleotide substitution was found at base 526 of GP IIIa cDNA by direct DNA sequencing analysis. The Yuk^b/b homozygous individuals bore G at this position while the Yuk^a/a had A. This base change results in the substitution of glutamine in Yuk^a for arginine in Yuk^b at amino acid residue 143 of glycoprotein IIIa molecule. Slot blotting analysis using sequence-specific oligonucleotide probes demonstrated that this Arg/Gln polymorphism is associated with the Yuk alloantigen system.

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