2,150 research outputs found
A Pseudo Shock Theory of Pressure Depression in Externally Pressurized Circular Thrust Gas Bearings
A theoretical investigation of the supersonic pressure depression in externally pressurized circular thrust gas bearings is developed with a pseudo shock wave model which replaces the concentrated normal shock wave model used in the previous paper. The pseudo shock theory on the basis of appropriate assumptions used by Crocco can explain the gradual recovery of pressure after supersonic expansion flow from a single central supply hole
Inhibitory Effect of Fermented Papaya Preparation on Hydroxyl Radical Generation from Methylguanidine
We have previously shown that extremely high level of guanidino compounds such as methylguanidine (MG), known as a neurotoxin and also a nephrotoxin, generate reactive oxygen species (ROS) using an electron spin resonance (ESR) technique with spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). In this in vitro study, the inhibitory effect of fermented papaya preparation (SAIDO-PS501:PS-501) on hydroxyl radical (·OH) generation from MG was examined using an ESR spectrometry, and it was found that PS-501 suppressed ·OH generation from MG in a dose-dependent manner. The ID50 value of PS-501 was 8 mg/ml. On the contrary, glucose itself did not suppress ·OH generation from MG up to100 mg/ml, whereas PS-501 almost completely suppressed ·OH generation from MG at a dose of 100 mg/ml. These results imply that PS-501 itself may have a beneficial effect of preventing ROS- and MG-related diseases
Relationship between Tourniquet Pressure and a Cross-Section Area of Superficial Vein of Forearm
This study investigated the appropriate tourniquet pressure (TP) and duration of tourniquet application for venipuncture by calculating the venous cross-section (VCS) area on ultrasonography. Twenty healthy volunteers without cardiovascular risk factors were enrolled in this study. A target vein (either a cephalic or median cubital vein) was selected on ultrasonography. The pneumatic tourniquet was inflated using a rapid cuff inflator system at setting pressure for 120sec. TP strength was varied from 20mmHg to 100mmHg, in 20mmHg increments. The order of TP was randomized. Compari-sons among more than 3 groups were performed by one-way repeated-measures ANOVA and the Bonferroni method. The VCS area increased rapidly until 10sec after tourniquet inflation. The VCS area then increased gradually until 30sec after tourniquet inflation. After that, the VCS area did not increase remarkably. The VCS area increased with TP strength up to 80mmHg, but the VCS area at TP 100mmHg decreased to less than that at TP 40mmHg. Based on these results, we recommend a tourniquet pressure of 60mmHg, and duration of tourniquet application is 30 to 60sec for venipuncture
Widely Extended [OIII] 88 um Line Emission around the 30 Doradus Region Revealed with AKARI FIS-FTS
We present the distribution map of the far-infrared [OIII] 88um line emission
around the 30 Doradus (30 Dor) region in the Large Magellanic Cloud obtained
with the Fourier Transform Spectrometer of the Far-Infrared Surveyor onboard
AKARI. The map reveals that the [OIII] emission is widely distributed by more
than 10' around the super star cluster R136, implying that the 30 Dor region is
affluent with interstellar radiation field hard enough to ionize O^{2+}. The
observed [OIII] line intensities are as high as (1-2) x 10^{-6} W m^{-2}
sr^{-1} on the peripheral regions 4'-5' away from the center of 30 Dor, which
requires gas densities of 60-100 cm^{-3}. However the observed size of the
distribution of the [OIII] emission is too large to be explained by massive
stars in the 30 Dor region enshrouded by clouds with the constant gas density
of 10^2 cm^{-3}. Therefore the surrounding structure is likely to be highly
clumpy. We also find a global correlation between the [OIII] and the
far-infrared continuum emission, suggesting that the gas and dust are well
mixed in the highly-ionized region where the dust survives in clumpy dense
clouds shielded from the energetic photons.Comment: 17 pages, 9 figures, accepted for publication in Publications of the
Astronomical Society of Japan (PASJ
Extreme case of Faraday effect: magnetic splitting of ultrashort laser pulses in plasmas
The Faraday effect, caused by a magnetic-field-induced change in the optical
properties, takes place in a vast variety of systems from a single atomic layer
of graphenes to huge galaxies. Currently, it plays a pivot role in many
applications such as the manipulation of light and the probing of magnetic
fields and material's properties. Basically, this effect causes a polarization
rotation of light during its propagation along the magnetic field in a medium.
Here, we report an extreme case of the Faraday effect where a linearly
polarized ultrashort laser pulse splits in time into two circularly polarized
pulses of opposite handedness during its propagation in a highly magnetized
plasma. This offers a new degree of freedom for manipulating ultrashort and
ultrahigh power laser pulses. Together with technologies of ultra-strong
magnetic fields, it may pave the way for novel optical devices, such as
magnetized plasma polarizers. In addition, it may offer a powerful means to
measure strong magnetic fields in laser-produced plasmas.Comment: 18 pages, 5 figure
Insect-induced daidzein, formononetin and their conjugates in soybean leaves.
In response to attack by bacterial pathogens, soybean (Gylcine max) leaves accumulate isoflavone aglucones, isoflavone glucosides, and glyceollins. In contrast to pathogens, the dynamics of related insect-inducible metabolites in soybean leaves remain poorly understood. In this study, we analyzed the biochemical responses of soybean leaves to Spodoptera litura (Lepidoptera: Noctuidae) herbivory and also S. litura gut contents, which contain oral secretion elicitors. Following S. litura herbivory, soybean leaves displayed an induced accumulation of the flavone and isoflavone aglycones 4',7-dihyroxyflavone, daidzein, and formononetin, and also the isoflavone glucoside daidzin. Interestingly, foliar application of S. litura oral secretions also elicited the accumulation of isoflavone aglycones (daidzein and formononetin), isoflavone 7-O-glucosides (daidzin, ononin), and isoflavone 7-O-(6'-O-malonyl-β-glucosides) (malonyldaidzin, malonylononin). Consistent with the up-regulation of the isoflavonoid biosynthetic pathway, folair phenylalanine levels also increased following oral secretion treatment. To establish that these metabolitic changes were the result of de novo biosynthesis, we demonstrated that labeled (13C9) phenylalanine was incorporated into the isoflavone aglucones. These results are consistent with the presence of soybean defense elicitors in S. litura oral secretions. We demonstrate that isoflavone aglycones and isoflavone conjugates are induced in soybean leaves, not only by pathogens as previously demonstrated, but also by foliar insect herbivory
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