Ordering Process and Its Hole Concentration Dependence of the Stripe Order in La{2-x}Sr{x}NiO{4}

Ordering process of stripe order in La{2-x}Sr{x}NiO{4} with x being around 1/3 was investigated by neutron diffraction experiments. When the stripe order is formed at high temperature, incommensurability \epsilon of the stripe order has a tendency to show the value close to 1/3 for the samples with x at both sides of 1/3. With decreasing temperature, however, \epsilon becomes close to the value determined by the linear relation of \epsilon = n_h, where n_h is a hole concentration. This variation of the \epsilon strongly affects the character of the stripe order through the change of the carrier densities in stripes and antiferromagnetic domains.Comment: 5 pages, 3 figures, REVTeX, to be published in Phys. Rev.

Molecular and biochemical studies of the Bacillus subtilis FtsY protein, a homologue of the α subunit of mammalian signal recognition particle

In mammalian cellls, the signal recognition particle(SRP) and the SRP receptor play a central role in targeting presecretory proteins to the membrane of the endoplasmic reticulum(ER). SRP is a ribonucleo-protein complex composed of one RNA(SRP 7S RNA) molecule and six proteins of 9, 14, 19, 54, 68, and 72 kDa. SRP interacts with the signal sequence of nascent polypeptide emerging from ribosomes and the complex formed is targeted and bound to a hetero-dimeric receptor consisting of SRα and SRβ on the ER. In contrast, it has been considered that the chaperones and Sec proteins play a pivotal role in targeting and translocation of secretory proteins in Escherichia coli. However, recently, the molecular homologues to the components of mammalian SRP have been identified in prokaryotes. In E. coli, 4.5S RNA and E. coli Ffh protein have been identified as homologues to the SRP 7S RNA and SRP54 of mammalian SRP, respectively. Furthermore, FtsY exhibits a homology with SRα. In Bacillus subtilis, small cytoplasmic RNA(scRNA) and B. subtilis Ffh protein have been also identified as homologues to the SRP 7S RNA and SRP54, respectively. Depletion of either the SRP RNA or SRP54 homologues ･･･Thesis (Ph. D. in Sciences)--University of Tsukuba, (B), no. 1714, 2001.3.23Includes bibliographical referencesTitlepage,Contens -- Abbreviations,Abstracts -- General Introduction -- Section I. Cloning and Characterization of the Bacillus subtilis ftsY (srb) Which product is a Homologue of the α-Subunit of Mammalian Signal Recognition Particle Receptor -- Section II. Expression of the ftsY Gene is Controlled by Different Promoters in Vegetative and Sporulating Cells of Bacillus subtilis, and functional analysis of FtsY protein -- General Discussion -- References -- Acknowledgement

Magnetic superelasticity and inverse magnetocaloric effect in Ni-Mn-In

Applying a magnetic field to a ferromagnetic Ni$_{50}$Mn$_{34}$In$_{16}$ alloy in the martensitic state induces a structural phase transition to the austenitic state. This is accompanied by a strain which recovers on removing the magnetic field giving the system a magnetically superelastic character. A further property of this alloy is that it also shows the inverse magnetocaloric effect. The magnetic superelasticity and the inverse magnetocaloric effect in Ni-Mn-In and their association with the first order structural transition is studied by magnetization, strain, and neutron diffraction studies under magnetic field.Comment: 6 pages, 8 figures. Published in the Physical Review