45 research outputs found
Variation of strong correlation effects in A-site ordered perovskites CaCu3Ti4-xRuxO12: Photoemission and inverse photoemission studies
We have systematically studied the strong correlation effects in A-site
ordered perovskites CaCu3Ti4-xRuxO12 (x = 0, 1, 3.5, 4) by using photoemission
and inverse photoemission spectroscopies. In x = 0, 1, 3.5, the peak positions
of the strongly correlated Cu 3d states around -3.8 eV and Ti 3d states around
3.6 eV little change. On the other hand, in x = 4, the Cu 3d states is observed
around -2.5 eV. These indicate that Ti plays an important role to retain the
strong correlation effects. In addition, the multiplet structures of Cu 3d
final states from -8 to -15 eV become weak as Ru increases, indicating the
reduction of the localized characters of Cu 3d states. At the Fermi level, we
observe the absence of spectral weight in x = 0, 1 and the development of Ru 4d
in-gap states between the Cu 3d and Ti 3d peaks in x = 3.5, 4, which give rise
to the metal-insulator transition between x = 1 and x = 3.5.Comment: 12 pages, 3 figure
Direct observation of DNA molecules in a convection flow of a drying droplet
The motion of single T4 DNA molecules (166 kilo-base
pairs) was studied by fluorescence microscopy in a drying droplet of
polyethylene glycol (PEG) solution on a glass surface. An ordered flow
was observed in the vicinity of the droplet contact line. A high
stretching of the DNA molecules was found at the droplet periphery,
whereas in its central part the DNA molecules were in a random coil
state. With the increase of PEG concentration, individual DNA
molecules show collapse transition directly from the stretched
conformation after the formation of nuclei at the ends of the chain.
Without PEG all the DNA molecules were in a random coil state and
slowly diffused to the droplet boundary. They were trapped in a narrow
region near the contact line
Resting cyst distribution and molecular identification of the harmful dinoflagellate Margalefidinium polykrikoides (Gymnodiniales, Dinophyceae) in Lampung Bay, Sumatra, Indonesia
Margalefidinium polykrikoides, an unarmored dinoflagellate, was suspected to be the causative agent of the harmful algal blooms - associated with massive fish mortalities - that have occurred continually in Lampung Bay, Indonesia, since the first bloom event in October 2012. In this study, after examination of the morphology of putative M. polykrikoides-like cysts sampled in bottom sediments, cyst bed distribution of this harmful species was explored in the inner bay. Sediment samples showed that resting cysts, including several morphotypes previously reported as M. polykrikoides, were most abundant on the northern coast of Lampung Bay, ranging from 20.6 to 645.6 cysts g(-1) dry sediment. Molecular phylogeny inferred from LSU rDNA revealed that the so-called Mediterranean ribotype was detected in the sediment while M. polykrikoides motile cells, four-cell chain forming in bloom conditions, belonged to the American-Malaysian ribotype. Moreover, hyaline cysts, exclusively in the form of four-cell chains, were also recorded. Overall, these results unequivocally show that the species M. polykrikoides is abundantly present, in the form of vegetative cells, hyaline and resting cysts in an Indonesian area