388 research outputs found

    A Search For Supernova Remnants in The Nearby Spiral Galaxy M74 (NGC 628)

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    We have identified nine new SNR candidates in M74 with [S II]/Hα\alpha \geq 0.4 as the basic criterion. We obtain [S II]/Hα\alpha ratio in the range from 0.40 to 0.91 and Hα\alpha intensities from 2.8 ×\times 101510^{-15} erg cm2^{-2} s1^{-1} to 1.7 ×\times 101410^{-14} erg cm2^{-2} s1^{-1}. We also present spectral follow-up observations of the SNR candidates and can confirm only three of them (SNR2, SNR3, and SNR5). The lack of confirmation for the rest might be due to the contamination by the nearby H II emission regions as well as due to the inaccurate positioning of the long slit on these objects. In addition, we search the ChandraChandra Observatory archival data for the X-ray counterparts to the optically identified candidates. We find positional coincidence with only three SNR candidates, SNR1, SNR2, and SNR8. The spectrum of SNR2 yields a shock temperature of 10.8 keV with an ionization timescale of 1.6 ×\times 1010^{10} s cm3^{-3} indicating a relatively young remnant in an early Sedov phase which is not supported by our optical wavelength analysis. Given the high luminosity of 1039^{39} erg s1^{-1} and the characteristics of the X-ray spectrum, we favor an Ultra Luminous X-ray Source interpretation for this source associated with an SNR. We calculate an X-ray flux upper limit of 9.0 ×\times 101510^{-15} erg cm2^{-2} s1^{-1} for the rest of the SNRs including spectroscopically identified SNR3 and SNR5.Comment: 10 pages, 8 figures, accepted to be published in A&

    The TIGRE gamma-ray telescope

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    TIGRE is an advanced telescope for gamma-ray astronomy with a few arcmin resolution. From 0.3 to 10 MeV it is a Compton telescope. Above 1 MeV, its multi-layers of double sided silicon strip detectors allow for Compton recoil electron tracking and the unique determination for incident photon direction. From 10 to 100 MeV the tracking feature is utilized for gamma-ray pair event reconstruction. Here we present TIGRE energy resolutions, background simulations and the development of the electronics readout system

    Investigations of Ancient Terra-cotta Sarcophagi, Excavated in Enez (Ainos) Turkey, by Instrumental Neutron Activation Analysis

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    Ten terra-cotta sarcophagi, together with a terra-cotta aryballos (perfume jar), excavated in Su Terazisi necropolis of Enez-Turkey (Ancient Ainos), were investigated by Instrumental Neutron Activation Analysis (INAA), to determine the concentration of thirty two chemical elements: Na, K, Ca, Fe, Sc, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Lu, Hf, Ta, Th and U. The dataset was submitted to multivariate statistical analysis. The classification was done by cluster analysis. The results demonstrated the occurrence of two different groups of terra-cotta samples. Group I contains nine sarcophagi and terra-cotta aryballos whereas group II contains only one sample (E09-ST5-M26). High correlations between La and Ce (r2 = 0.92), and U and Th (r2 = 0.91) indicated that local clay was used for manufacturing the terra-cotta sarcophagi and aryballos but probably the claybed used for E09-ST5-M26 was different from that of others

    Immunohistochemical neuroinflammatory markers in the hippocampus of PTZ-kindled rats under conditions of rapamycin and axitinib treatment

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    The aim of the study is to determine the level of HIF-1α, TNF-α, and NF-kB in the hippocampus of kindled rats treated with rapamycin and axitinib. Materials and methods. Kindling was produced in 29 rats by administration of three-week pentylenetetrazole (PTZ, 35.0 mg/kg, i.p.). Treatment with rapamycin (0.5 mg/kg, i.p.) and axitinib (2.5 mg/kg, i.p.) was performed for ten days in fully kindled rats. The avidin-biotin-peroxidase method was used for hippocampal slice staining. For negative control, staining was performed using only secondary antibodies. Results. The HIF-1α expression increased in kindled rats raised by 1.77 times compared to the control (p<0.001). Axitinib treatment resulted in of HIF-1α level of 16.7 % (p<0.05) compared with kindled animals, while combined treatment with rapamycin and axitinib reduced HIF-1α by 33.8 % (p<0.01). In kindled rats, TNF-α expression was 3.74 times greater than in control (p<0.001). Rapamycin treatment reduced TNF-α by 31.0 % (p<0.01). Axitinib treatment caused a reduction of TNF-α by 21.1 % (p<0.05). Combined treatment with rapamycin and axitinib reduced TNF-α by 48.0 % (p<0.001) but still exceeded the TNF-α in control by 1.95 times (p<0.01). NF-kB level in kindled rats exceeded the control by three times (p0.05), while axitinib – by 26.5 % (p<0.05) compared with kindled rats. Combined treatment with rapamycin and axitinib resulted in NF-kB reduction by 56.7 % compared with kindled rats (p<0.001). Conclusions. PTZ-kindling resulted in an increase in the immunoreactivity of HIF-1α, TNF-α, and NF-kB in the hippocampus. Combined treatment with rapamycin and axitinib engendered prevention of generalized seizures and normalized the level of HIF-1α and NF-kB with a significant reduction of TNF-α. Effects of treatment favours of synergy action of rapamycin and axitini
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