485 research outputs found
A Study on a High Frequency Application of Thyristor
Static switches utilizing thyristor capable of switching at high frequency are described. A brief summary of the experimental operation of the device is included, followed by an analysis of the static switches. Design procedures and graphs are developed that make possible the design of such static switches based upon design criteria.Article信州大学工学部紀要 21: 11-20 (1966)departmental bulletin pape
Effect of a small molecule inhibitor of nuclear factor-κB nuclear translocation in a murine model of arthritis and cultured human synovial cells
A small cell-permeable compound, dehydroxymethylepoxyquinomicin (DHMEQ), does not inhibit phosphorylation and degradation of IκB (inhibitor of nuclear factor-κB [NF-κB]) but selectively inhibits nuclear translocation of activated NF-κB. This study aimed to demonstrate the antiarthritic effect of this novel inhibitor of the NF-κB pathway in vivo in a murine arthritis model and in vitro in human synovial cells. Collagen-induced arthritis was induced in mice, and after onset of arthritis the mice were treated with DHMEQ (5 mg/kg body weight per day). Using fibroblast-like synoviocyte (FLS) cell lines established from patients with rheumatoid arthritis (RA), NF-κB activity was examined by electrophoretic mobility shift assays. The expression of molecules involved in RA pathogenesis was determined by RT-PCR, ELISA, and flow cytometry. The proliferative activity of the cells was estimated with tritiated thymidine incorporation. After 14 days of treatment with DHMEQ, mice with collagen-induced arthritis exhibited decreased severity of arthritis, based on the degree of paw swelling, the number of swollen joints, and radiographic and histopathologic scores, compared with the control mice treated with vehicle alone. In RA FLS stimulated with tumor necrosis factor-α, activities of NF-κB components p65 and p50 were inhibited by DHMEQ, leading to suppressed expression of the key inflammatory cytokine IL-6, CC chemokine ligand-2 and -5, matrix metalloproteinase-3, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1. The proliferative activity of the cells was also suppressed. This is the first demonstration of an inhibitor of NF-κB nuclear translocation exhibiting a therapeutic effect on established murine arthritis, and suppression of inflammatory mediators in FLS was thought to be among the mechanisms underlying such an effect
ASCA Observations of Two Ultra-Luminous Compact X-Ray Sources in the Edge-on Spiral Galaxy NGC 4565
The edge-on spiral galaxy NGC 4565 was observed for 35 ks with ASCA in
the 0.5-10 keV energy band. The X-ray emission was dominated by two bright
sources, which can be identified with two point-like X-ray sources seen in the
ROSAT HRI image. The observed 0.5-10 keV fluxes of these sources, and , % % imply bolometric
luminosities of and ,
respectively. They exhibit similar spectra, which can be explained by emission
from optically thick accretion disks with the inner disk temperature of 1.4-1.6
keV. One of them, coincident in position with the nucleus, shows too low
absorption to be the active nucleus seen through the galaxy disk. Their spectra
and high luminosities suggest that they are both mass accreting black hole
binaries. However the black-hole mass required by the Eddington limit is rather
high (), and the observed disk temperature is too high to be
compatible with the high black-hole mass. Several attempts are made to solve
these problesms.Comment: 20page
X-Ray Spectra of the Narrow-Line Seyfert 1 Galaxy Ton S180 in Comparison with Galactic Black Holes
An analysis was made of 0.3-15 keV X-ray spectra of a Narrow-Line Seyfert 1
Galaxy, Ton S180, using archival data from ASCA, RXTE, and XMM-Newton. At
energies above 2.5 keV, a power-law with a photon index of ~ 2.3 successfully
and consistently reproduced the spectra from all of these observatories.
Assuming this power-law component to extend toward lower energies, a soft
excess, which is one of the most remarkable features of Narrow-Line Seyfert 1
Galaxies, is explained by another power-law multiplied by a thermal cutoff at ~
0.4 keV. Some similarities have been observed between this object and Galactic
black hole binaries in very high state, the latter being realized under high
accretion rates. Attempts have been made to interpret the soft excess in terms
of Comptonization of the disk photons by an electron cloud surrounding the
accretion disk, like BHBs in a very high state.Comment: 7 pages, 7 figure
Suzaku Observations of M82 X-1 : Detection of a Curved Hard X-ray Spectrum
A report is presented on Suzaku observations of the ultra-luminous X-ray
source X-1 in the starburst galaxy M82, made three time in 2005 October for an
exposure of ~ 30 ks each. The XIS signals from a region of radius 3 around the
nucleus defined a 2-10 keV flux of 2.1 x 10^-11 erg s-1 cm-2 attributable to
point sources. The 3.2-10 keV spectrum was slightly more convex than a
power-law with a photon index of 1.7. In all observations, the HXD also
detected signals from M82 up to ~ 20 keV, at a 12-20 keV flux of 4.4 x 10^-12
erg s-1 cm-2 . The HXD spectrum was steeper than that of the XIS. The XIS and
HXD spectra can be jointly reproduced by a cutoff power-law model, or similar
curved models. Of the detected wide-band signals, 1/3 to 2/3 are attributable
to X-1, while the remainder to other discrete sources in M82. Regardless of the
modeling of these contaminants, the spectrum attributable to X-1 is more curved
than a power-law, with a bolometric luminosity of (1.5 -3) x 10 ^40 erg s-1.
These results are interpreted as Comptonized emission from a black hole of
100-200 solar masses, radiating roughly at the Eddington luminosity.Comment: 19 pages, 9 figures, accepted in Publications of the Astronomical
Society of Japa
Discovery of a bright transient ultraluminous X-ray source Suzaku J1305-4931 in NGC 4945
This paper reports the discovery of a bright X-ray transient source, Suzaku
J1305-4913, in the south-west arm of the nearby Seyfert II galaxy NGC 4945. It
was detected at a 0.5 -- 10 keV flux of erg cm
s during the Suzaku observation conducted on 2006 January 15 -- 17, but
was undetectable in a shorter observation on 2005 August 22 --23, with an upper
limit of erg cm s (90% confidence level).
At a distance of 3.7 Mpc, the bolometric luminosity of the source becomes
erg s, where and is the disk inclination. Therefore, the source is
classified into so-called ultraluminous X-ray sources (ULXs). The time-averaged
X-ray spectrum of the source is described by a multi-color disk model, with the
innermost accretion disk temperature of
keV. During the 2006 January observation, it varied by a factor of 2 in
intensity, following a clear correlation of .
It is inferred that the innermost disk radius stayed constant at
km, suggesting the presence of a
standard accretion disk. Relating with the last stable orbit
around a non-rotating black hole yields a rather low black hole mass, solar masses, which would imply that the source is shining at a
luminosity of times the Eddington limit. These results
can be better interpreted by invoking sub-Eddington emission from a rapidly
spinning black hole with a mass of 20 -- 130 solar masses.Comment: 21 pages, 10 figures, Accepted for PASJ 2nd Suzaku special issu
Effect of Air and Root Temperatures on the Development of Flower Cluster Borne on the Forced Lateral Shoot of Muscat of Alexandria Grapes
ブドウ,Muscat of Alexandriaの2期作栽培において,2期作目の花穂は1期作目にくらべて発育が著しく劣るが,これは2期作目の発芽から開花までが夏期にあたるため,この時期の気温が高すぎることも大きく影饗している. そこで本実験では,気温条件が高すぎる場合に地温を人為的に操作することによって花穂の発育不良を回復することができるかどうかを確めるために,ポット植えのMuscat of Alexandriaの2番枝の発芽直前から気温(30℃,25℃,自然)と地温(30℃,25℃,20℃)をかえて,2番枝上の花穂の発育を比較した. (1)2番枝の生長はいずれの気温の場合にも地温20℃区で劣ったが,とくに気温が高いほどこの傾向が著しかった. 花穂の伸長もこれとほぼ同様な傾向がみられ,とくに30℃-20℃(気温-地温)区では,すべての花穂が発育を停止し,発芽後約20日目には枯死した. (2)気温が30℃でも地温25℃および30℃の両区では気温25℃あるいは自然気温(平均23.4℃)の場合と同じように花穂は発育して開花に至ったが,この両区では開花初期から落花が著しく,満開後約10日目における結実率は最も低かった. いっぽう,25℃-25℃区では第2次花穂数,花らい数ともに最も多く花穂の発育はすぐれ,また,この区の結実率は高かった. (3)以上の結果から,Muscat of Alexandriaの2番枝に着生した花穂の高温による発育不良は地温を下げることによって回復することは不可能で,気温が高いほど地面も高温を必要としたが,気温が30℃恒温では地温をどのように調整しても結実が悪く,気温条件としては高すぎると思われた
Effects of Root Temperature on Development of Flower Cluster, Berry Set and Berry Growth of Muscat of Alexandria Grapes
ブドウ“マスカット・オブ・アレキサンドリア"のつぎ木苗(H.F.台)について,発芽約3週前から落果終了期まで(実験I)と,開花約10日前から果肉細胞の分裂終了期まで(実験II)地温処理を行い,花穂の発育,結実,果粒の発育等に及ぼす影饗を調査した. またこの時期までの処理が収穫果に及ぼす影響についても調査した. 1) 実験Iにおいて,花穂の伸長は30℃区ですぐれ,花穂当りの小花数もこの区で最も多かったが,これ以下の地温では小花数に大きな差はみられなかった. 一方,33℃区では花穂の発育異常がみられ,花穂当りの小花数は著しく少なく,小花分化期の地温条件としては高温すぎると思われた. 2) 結実率は実験Iでは18,20,25,30℃の各区で、また実験IIでは20,25,30℃の各区で高く,一方,15℃区では実験I,IIともに最も低かった. 花穂の発育異常がみられた33℃区でも結実率はすぐれた. 結実率と人工培地上での花粉の発芽率との間には明確な関連は認められなかった. 3) 処理終了時の果粒の大きさは,実験I,IIともに25,30℃の両区ですぐれ,15℃区で劣った. 15℃区では果肉の外壁及び内壁の細胞数は他の区よりもいく分少ない程度であったが,その大きさ,とくに内壁細胞の大きさは著しく小さかった. また実験Iの33℃区と実験IIの35℃区では,外壁及び内壁の細胞数が少ない傾向であった. 4) 収穫果の大きさは,実験Iでは18,20,25℃の各区で,また実験IIでは25,30,35℃の各区ですぐれたのに対し,15℃区では実験I,IIともに最も小さかった. 果粒中の種子数は15℃区で著しく少なく,とくに実験Iの15℃区では果粒当り2個以下のものが70%以上を占めた. 果汁の屈折計示度及び酸含量には実験I,IIともに処理区間での差は認められなかった
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