231 research outputs found
Detection of highly ionized O and Ne absorption lines in the X-ray spectrum of 4U1820-303 in the globular cluster, NGC 6624
We searched for absorption lines of highly ionized O and Ne in the energy
spectra of two Low-mass X-ray binaries, 4U1820-303 in the globular cluster
NGC6624 and Cyg X-2, observed with the Chandra LETG, and detected O VII, O VIII
and Ne IX absorption lines for 4U1820-303. The equivalent width of the O VII K
alpha line was 1.19 +0.47/-0.30 eV (90 % errors) and the significance was 6.5
sigma. Absorption lines were not detected for Cyg X-2 with a 90 % upper limit
on the equivalent width of 1.06 eV for O VII K alpha. The absorption lines
observed in 4U1820-303 are likely due to hot interstellar medium, because O
will be fully photo-ionized if the absorbing column is located close to the
binary system. The velocity dispersion is restricted to b = 200 - 420 km/s from
consistency between O VII K alpha and K beta lines, Ne/O abundance ratio, and H
column density. The average temperature and the O VII density are respectively
estimated to be log(T[K]) = 6.2 - 6.3 and n(OVII) = (0.7 - 2.3) x 10^{-6}
cm^{-3}. The difference of O VII column densities for the two sources may be
connected to the enhancement of the soft X-ray background (SXB) towards the
Galactic bulge region. Using the polytrope model of hot gas to account for the
SXB we corrected for the density gradient and estimated the midplane O VII
density at the solar neighborhood. The scale height of hot gas is then
estimated using the AGN absorption lines. It is suggested that a significant
portion of both the AGN absorption lines and the high-latitude SXB emission
lines can be explained by the hot gas in our Galaxy.Comment: Accepted for publication in ApJ. 7 pages, 9 eps figure
The Inhibitory Effect of Conjugated and Polyunsaturated Fatty Acids on the Growth of Human Cancer Cell Lines
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The Effect of Dual-Hemisphere Transcranial Direct Current Stimulation Over the Parietal Operculum on Tactile Orientation Discrimination
The parietal operculum (PO) often shows ipsilateral activation during tactile object perception in neuroimaging experiments. However, the relative contribution of the PO to tactile judgment remains unclear. Here, we examined the effect of transcranial direct current stimulation (tDCS) over bilateral PO to test the relative contributions of the ipsilateral PO to tactile object processing. Ten healthy adults participated in this study, which had a double-blind, sham-controlled, cross-over design. Participants discriminated grating orientation during three tDCS and sham conditions. In the dual-hemisphere tDCS conditions, anodal and cathodal electrodes were placed over the left and right PO. In the uni-hemisphere tDCS condition, anodal and cathodal electrodes were applied over the left PO and contralateral orbit, respectively. In the tDCS and sham conditions, we applied 2 mA for 15 min and for 15 s, respectively. Computational models of electric fields (EFs) during tDCS indicated that the strongest electric fields were located in regions in and around the PO. Compared with the sham condition, dual-hemisphere tDCS improved the discrimination threshold of the index finger contralateral to the anodal electrode. Importantly, dual-hemisphere tDCS with the anodal electrode over the left PO yielded a decreased threshold in the right finger compared with the uni-hemisphere tDCS condition. These results suggest that the ipsilateral PO inhibits tactile processing of grating orientation, indicating interhemispheric inhibition (IHI) of the PO
On the lack of strong O-line excess in the Coma cluster outskirts from Suzaku
About half of the baryons in the local Universe are thought to reside in the
so-called warm-hot intergalactic medium (WHIM) at temperatures of 0.1-10
million K. Thermal soft excess emission in the spectrum of some cluster
outskirts that contains OVII and/or OVIII emission lines is regarded as
evidence of the WHIM, although the origin of the lines is controversial due to
strong Galactic and solar system foreground emission. We observed the Coma-11
field, where the most prominent thermal soft excess has ever been reported,
with Suzaku XIS in order to make clear the origin of the excess. We did not
confirm OVII or OVIII excess emission. The OVII and OVIII intensity in Coma-11
is more than 5 sigma below that reported before and we obtained 2 sigma upper
limits of 2.8 and 2.9 photons cm^-2 s^-1 sr^-1 for OVII and OVIII,
respectively. The intensities are consistent with those in another field
(Coma-7) that we measured, and with other measurements in the Coma outskirts
(Coma-7 and X Com fields with XMM-Newton). We did not confirm the spatial
variation within Coma outskirts. The strong oxygen emission lines previously
reported are likely due to solar wind charge exchange.Comment: 5 pages, 3 figures. Accepted for publication in Ap
Systemic Activation of Biomarkers by Varix
Objective: To evaluate the relationship between systemic inflammatory biomarkers and efficacy of surgical treatment of primary varicose veins of the lower extremities.
Methods: Total 12 patients who underwent endovenous laser ablation or stripping of varicose veins and six healthy subjects were enrolled. Structural and molecular changes of varices were assessed by immunohistochemical staining with anti-monocyte chemotactic protein-1 (MCP-1). MCP-1 and interleukin-6 (IL-6) levels in systemic antecubital blood were measured before and at 12 weeks after treatment.
Results: Immunohistochemical staining revealed prominent manifestation of MCP-1-positive endothelial cells in the walls of varices. Preoperative serum MCP-1 and IL-6 levels in the patients were significantly higher than those in the control (166±12 pg/mL vs 99±10 pg/mL, p=0.003; 5.1±0.95 pg/mL vs 0.0±0.0 pg/mL, p=0.001, respectively). The values were significantly correlated with the severity of chronic venous insufficiency (CVI). Postoperative serum MCP-1 level significantly decreased compared with the preoperative level (152±10 pg/mL vs 166±12 pg/mL, p=0.048). The values after endovenous laser ablation did not significantly decrease compared with those after stripping.
Conclusion: Varicose veins with CVI increase inflammatory biomarker levels in the local tissue and systemic blood. Appropriate treatment of symptomatic varicose veins decreases inflammatory biomarker levels
X-ray Spectral Study of the extended emission,'the Cap', located 11.6 kpc above the disk of M82
The extended X-ray emission from 'the Cap' region located 11' (11.6 kpc)
above the disk of the starburst galaxy M82 has been observed with Suzaku and
XMM-Newton. Owing to the good energy resolution and the large collecting area
of the XIS on Suzaku, combined with similar properties of the EPIC instrument
on XMM-Newton, we have clearly detected K-shell emission lines from O VII, O
VIII, Ne X, Mg XI, Mg XII and the Fe-L complex. Two optically-thin thermal
plasma components are required to fit the observed X-ray spectra. We have
determined the metal abundances of O, Ne, Mg, Si and Fe in this region for the
first time. Their metal abundance ratios agree well with those of metal-poor
stars and the model prediction of metals synthesized by type-II supernovae, but
they are not consistent with the metallicities of type-Ia supernovae. This
result is support for the idea that the origin of the metals in the Cap is
type-II supernovae explosions occurring in the starburst regions in the M82
galaxy. We discuss the possible contribution from sputtered dust grains to the
metals in the Cap. An emission line consistent with the C VI transition of n=4
to 1 at 0.459 keV is marginally detected, although it is not statistically
significant at the 99% confidence level; the presence of this line would
suggest charge-exchange processes in the Cap.Comment: 16 pages, 10 figuer
Photoinduced swing of a diarylethene thin broad sword shaped crystal:a study on the detailed mechanism
We report a swinging motion of photochromic thin broad sword shaped crystals upon continuous irradiation with UV light. By contrast in thick crystals, photosalient phenomena were observed. The bending and swinging mechanisms are in fact due to molecular size changes as well as phase transitions. The first slight bending away from the light source is due to photocyclization-induced surface expansion, and the second dramatic bending toward UV incidence is due to single-crystal-to-single-crystal (SCSC) phase transition from the original phase I to phase IIUV. Upon visible light irradiation, the crystal returned to phase I. A similar SCSC phase transition with a similar volume decrease occurred by lowering the temperature (phase IIItemp). For both photoinduced and thermal SCSC phase transitions, the symmetry of the unit cell is lowered; in phase IIUV the twisting angle of disordered phenyl groups is different between two adjacent molecules, while in phase IIItemp, the population of the phenyl rotamer is different between adjacent molecules. In the case of phase IIUV, we found thickness dependent photosalient phenomena. The thin broad sword shaped crystals with a 3 mu m thickness showed no photosalient phenomena, whereas photoinduced SCSC phase transition occurred. In contrast, large crystals of several tens of mu m thickness showed photosalient phenomena on the irradiated surface where SCSC phase transition occurred. The results indicated that the accumulated strain, between isomerized and non-isomerized layers, gave rise to the photosalient phenomenon
Plasma levels of matrix metalloproteinaseâ9 (MMPâ9) are associated with cognitive performance in patients with schizophrenia
Aim: Matrix metalloproteinaseâ9 (MMPâ9) has been shown to modulate synaptic plasticity and may contribute to the pathophysiology of schizophrenia. This study investigated the peripheral levels of MMPâ9 and its association with cognitive functions in patients with schizophrenia to see the possible involvement of MMPâ9 in pathophysiology of schizophrenia, especially in cognitive decline.
Methods: We measured the plasma levels of MMPâ9 in 257 healthy controls and 249 patients with schizophrenia, including antipsychotic drugâfree patients. We also explored the possible association between plasma MMPâ9 levels and cognitive performance in healthy controls and patients with schizophrenia using the Wechsler Adult Intelligence Scale, Third Edition (WAISâ III), the Wechsler Memory ScaleâRevised (WMSâR), and the Rey Auditory Verbal Learning Test (AVLT).
Results: We found that the plasma levels of MMPâ9 were significantly higher in patients with schizophrenia, including antipsychotic drugâfree patients, than in healthy controls. We found a significant negative association between plasma MMPâ9 levels and cognitive performance in controls and patients with schizophrenia.
Conclusion: Together, these convergent data suggest a possible biological mechanism for schizophrenia, whereby increased MMPâ9 levels are associated with cognitive impairment
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