422 research outputs found
Instability of liquid jet penetrated into stream in channel
Penetration process and an instability on a liquid jet impinging to a stream
of the same fluid in a channel is focused. The jet penetrated into the stream
is wrapped by entrained air, and coalesces with the stream when the air sheath
around the jet collapses. We introduce instability arisen on the jet and the
vigorous effect of the entrained-air sheath on the dynamic behavior of the jet
in this fluid dynamics video
Method for Assessing X-ray-Induced Hydroxyl Radical Scavenging Activity of Biological Compounds/Materials
A method for correctly assessing hydroxyl radical scavenging activity of antioxidative chemicals and/or biological compounds/materials was proposed. This method can simultaneously assess two factors, i.e. hydroxyl radical scavenging and 5,5-dimethyl-2-hydroxy-1-pyrrolidine-N-oxide (hydroxyl radical adduct of 5,5-dimethyl-1-pyrroline-N-oxide) reducing ability, as antioxidative properties. In this paper, some biologically common hydrophilic molecules, cell culture media, and rat plasma were tested. X-ray induced hydroxyl radical can be detected using the electron paramagnetic resonance spin trapping technique. Using X-ray irradiation of the reaction mixture as the hydroxyl radical source, the true hydroxyl radical scavenging ability of the subjected antioxidant can be assessed. In addition, the method simultaneously measures the reduction of 5,5-dimethyl-2-hydroxy-1-pyrrolidine-N-oxide, to estimate the reducing ability of the antioxidant. Biological materials, such as sugars and proteins, could abolish hydroxyl radical at the biological concentration. Ascorbic acid showed reducing ability at the biological concentration. The simultaneous assessment of hydroxyl radical scavenging and reducing ability of antioxidants can be an informative index for antioxidants
Multi-line split DNA synthesis: a novel combinatorial method to make high quality peptide libraries
BACKGROUND: We developed a method to make a various high quality random peptide libraries for evolutionary protein engineering based on a combinatorial DNA synthesis. RESULTS: A split synthesis in codon units was performed with mixtures of bases optimally designed by using a Genetic Algorithm program. It required only standard DNA synthetic reagents and standard DNA synthesizers in three lines. This multi-line split DNA synthesis (MLSDS) is simply realized by adding a mix-and-split process to normal DNA synthesis protocol. Superiority of MLSDS method over other methods was shown. We demonstrated the synthesis of oligonucleotide libraries with 10(16 )diversity, and the construction of a library with random sequence coding 120 amino acids containing few stop codons. CONCLUSIONS: Owing to the flexibility of the MLSDS method, it will be able to design various "rational" libraries by using bioinformatics databases
A Discovery of a Peculiar Pulsar in the Small Magellanic Cloud
We report on a peculiar X-ray binary pulsar IKT1 = RXJ0047.3-7312 observed
with XMM-Newton in Oct. 2000. The X-ray spectrum is described by a
two-component spectrum. The hard component has a broken power-law with
respective photon indices of 0.2 and 1.8, below and above the break energy at
5.8 keV. The soft component can be modeled by a blackbody of kT = 0.6 keV. The
X-ray flux shows a gradual decrease and periodic variations of about 4000 s.
The averaged flux in 0.7-10.0 keV is 2.9x10^-12 ergs/cm^2/s, which is ~10 times
brighter than that in a ROSAT observation in Nov. 1999. In addition to the
4000-s variation, we found coherent pulsations of 263 +/- 1 s. These
discoveries strengthen the Be/X-ray binary scenario proposed by the ROSAT and
ASCA observations on this source, and confirm that most of the hard sources in
the Small Magellanic Cloud are X-ray binary pulsars. A peculiar property of
this XBP is that the coherent pulsations are found only in the soft component,
and the folded light curve shows a flat top shape with a sharp dip. We discuss
the nature of this XBP focusing on the peculiar soft component.Comment: 5 pages, 5figures, Accepted for publication in PAS
Momentum-resolved resonant photoelectron spectroscopic study for 1T-TiSe: Observation of negative q in the Fano resonance due to inter-atomic interaction in the valence band
The remarkable properties of (1T-)TiSe among the transition metal
dichalcogenides have attracted the attention of many researchers due to its
peculiar behavior during the charge density wave (CDW) transition. Therefore,
it is highly desirable to study its electronic structure down to the atomic
orbitals. In the present research, we applied momentum-resolved resonant
photoelectron spectroscopy to study TiSe at the Ti2p-Ti3d absorption edge
by using a momentum microscope, which can simultaneously detect the electronic
states in a wide range. We have also used constant initial state
(CIS) spectroscopy and density functional theory (DFT) calculations to reveal
the hybridization between the Ti3d and Se4p orbitals within the valence band at
the Gamma point at room temperature. In addition, an interesting result comes
from our analysis of the CIS spectrum for the energy band located at a binding
energy of 2 eV at the M-point. This band, mainly composed of the Se4p orbital,
exhibited a Fano line profile at the Ti2p edge, with a negative value of the
parameter "". This is the first clear evidence of the inter-atomic
interaction during the valence band photoelectron emission process. This
behavior differs significantly from the standard resonant photoelectron
emission, which usually involves intra-atomic interactions. It also differs
from the multi-atom resonant photoelectron emission (MARPE) observed in the
core-level photoelectron emission, as we focus on the photoelectron emission
from the valence band in this research
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