8,113 research outputs found

    Pair Production of Scalar Dyons in Kerr-Newman Black Holes

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    We study the spontaneous pair production of scalar dyons in the near extremal dyonic Kerr-Newman (KN) black hole, which contains a warped AdS3_3 structure in the near horizon region. The leading term contribution of the pair production rate and the absorption cross section ratio are also calculated using the Hamilton-Jacobi approach and the thermal interpretation is given. In addition, the holographic dual conformal field theories (CFTs) descriptions of the pair production rate and absorption cross section ratios are analyzed both in the JJ-, QQ- and PP-pictures respectively based on the threefold dyonic KN/CFTs dualities.Comment: 12 pages, 3 figures, revtex4. arXiv admin note: text overlap with arXiv:1607.0261

    Proto-Model of an Infrared Wide-Field Off-Axis Telescope

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    We develop a proto-model of an off-axis reflective telescope for infrared wide-field observations based on the design of Schwarzschild-Chang type telescope. With only two mirrors, this design achieves an entrance pupil diameter of 50 mm and an effective focal length of 100 mm. We can apply this design to a mid-infrared telescope with a field of view of 8 deg X 8 deg. In spite of the substantial advantages of off-axis telescopes in the infrared compared to refractive or on-axis reflective telescopes, it is known to be difficult to align the mirrors in off-axis systems because of their asymmetric structures. Off-axis mirrors of our telescope are manufactured at the Korea Basic Science Institute (KBSI). We analyze the fabricated mirror surfaces by fitting polynomial functions to the measured data. We accomplish alignment of this two-mirror off-axis system using a ray tracing method. A simple imaging test is performed to compare a pinhole image with a simulated prediction.Comment: 14 pages, 16 figure

    Apoptotic properties of polysaccharide isolated from fruiting bodies of medicinal mushroom Fomes fomentarius in human lung carcinoma cell line

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    AbstractMushrooms are known to complement chemotherapy and radiation therapy by countering the side effects of cancer. Recently, there has been great interest in isolation of novel bioactive compounds from mushrooms due to their numerous health beneficial effects. Chemically water-extractable polysaccharide (MFKF-AP1β), with a molecular weight of 12kDa, was isolated from fruiting bodies of mushroom Fomes fomentarius. In this research, we investigated the anti-tumor effects of MFKF-AP1β on human lung carcinoma A549 cells. Results showed that MFKF-AP1β markedly inhibited A549 cell growth in a dose-dependent manner based on the amount of lactate dehydrogenase (LDH) released and morphological alterations. In addition, MFKF-AP1β induced cellular apoptosis by causing single-stranded DNA breakage, as evidenced by apoptosis assay. Furthermore, MFKF-AP1β (25–100μg/ml) significantly induced single-stranded DNA breakage in A549 cells, as shown by comet assay.Taken together, our results demonstrate that MFKF-AP1β has strong anti-tumor effects mediated through induction of apoptosis. Therefore, MFKF-AP1β could be useful in lung chemotherapy

    Temperature change in pig rib bone during implant site preparation by low-speed drilling

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    OBJECTIVES: The purpose of this study was to evaluate the temperature change during low-speed drilling using infrared thermography. MATERIAL AND METHODS: Pig ribs were used to provide cortical bone of a similar quality to human mandible. Heat production by three implant drill systems (two conventional drilling systems and one low-speed drilling system) was evaluated by measuring the bone temperature using infrared thermography. Each system had two different bur sizes. The drill systems used were twist drill (2.0 mm/2.5 mm), which establishes the direction of the implant, and finally a 3.0 mm-pilot drill. Thermal images were recorded using the IRI1001 system (Infrared Integrated Systems Ltd.). Baseline temperature was 31±1ºC. Measurements were repeated 10 times, and a static load of 10 kg was applied while drilling. Data were analyzed using descriptive statistics. Statistical analysis was conducted with two-way ANOVA. RESULTS AND CONCLUSIONS: Mean values (n=10 drill sequences) for maximum recorded temperature (Max TºC), change in temperature (ΔTºC) from baseline were as follows. The changes in temperature (ΔTºC) were 1.57ºC and 2.46ºC for the lowest and the highest values, respectively. Drilling at 50 rpm without irrigation did not produce overheating. There was no significant difference in heat production between the 3 implant drill systems (p>;0.05). No implant drill system produced heat exceeding 47ºC, which is the critical temperature for bone necrosis during low-speed drilling. Low-speed drilling without irrigation could be used during implant site preparation
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