507 research outputs found

    Mass and Angular momentum of Black Holes in New Massive Gravity

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    We obtain mass and angular momentum of black holes as conserved charges in three dimensional new massive gravity, after presenting the explicit expression for the potential of the conserved charges. This confirms the expression of those charges obtained in several ways, in particular through AdS/CFT correspondence, and shows us that the first law of black hole thermodynamics is valid in these black holes. We also comment about conserved charges in new type black holes with the emphasis on the AdS/CFT correspondence as guiding principle.Comment: minor corrections, added conclusion, accepted in PR

    The Impact of Corporate Social Responsibility and Irresponsibility on Corporate Financial Performance: An Event Study of Korean Conglomerates

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    Department of Management EngineeringCorporate Social Responsibility (CSR) is regarded as an integral part of management and is particularly important for corporate sustainability. Although CSR is performed in the context of corporate survival, Corporate Social Irresponsibility (CSI) occurs at the same time. Furthermore, both CSR and CSI influence Corporate Financial Performance (CFP) either directly or indirectly. Thus, in this study, I wanted to research the impact of CSR and CSI on CFP through an event study. Empirical data were collected from three years of news articles for affiliates of Korean conglomerates. The sample data consisted of 1,254 CSR news items and 267 CSI news items. As a result, I found that CSR has a positive impact on CFP, whereas CSI does not. More specifically, philanthropic CSR showed a strongly positive relationship with CFP, whereas economic, legal, and ethical CSR presented no significant relationship. Regardless of whether CSI is intentional or unintentional, it has no effect on CFP.ope

    A Calculation of Initial Cable Force for Ko-Ha Grand Bridge

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    The primary objective of initial shape analysis of a cable stayed bridge is to calculate initial installation cable tension forces and to evaluate fabrication camber of main span and pylon providing the final longitudinal profile of the bridge at the end of construction. In addition, the initial cable forces depending on the alternation of the bridge’s shape can be obtained from the analysis, and will be used to provide construction safety during construction. In this research, we conducted numerical experiments for initial shape of Ko-ha bridge, which will be constructed in the near future, using three different typical methods such as continuous beam method, linear truss method, and IIMF (Introducing Initial Member Force) metho

    Association of Epidermal Growth Factor Receptor Mutations with Metastatic Presentations in Non-Small Cell Lung Cancer

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    We performed this retrospective study to assess the association of epidermal growth factor receptor (EGFR) with metastatic presentations in advanced non-small cell lung cancer (NSCLC). The data from 125 patients with stage III or IV NSCLC were analyzed. We detected EGFR mutations in 36 NSCLC patients. EGFR mutations were predominant in never-smokers (P < .001), patients with adenocarcinomas (P < .001), and female patients (P < .001). When the metastatic sites were analyzed, pleural metastases were associated with a high incidence of EGFR mutations (P = .028). Particularly, pleural metastases with minimal effusion (PMME) were associated with EGFR mutational status (P = .001). Patients with N3 lesions were less likely to harbor EGFR mutations (P = .033). On multivariate analysis, N3 lesions (P = .017) and PMME (P < .001) remained significant factors for EGFR mutations. EGFR mutations may be associated with different presentations of pleural and N3 nodal metastases

    Unleashing the full potential of Hsp90 inhibitors as cancer therapeutics through simultaneous inactivation of Hsp90, Grp94, and TRAP1

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    Cancer therapeutics: Extending a drug&apos;s reach A new drug that blocks heat shock proteins (HSPs), helper proteins that are co-opted by cancer cells to promote tumor growth, shows promise for cancer treatment. Several drugs have targeted HSPs, since cancer cells are known to hijack these helper proteins to shield themselves from destruction by the body. However, the drugs have had limited success. Hye-Kyung Park and Byoung Heon Kang at Ulsan National Institutes of Science and Technology in South Korea and coworkers noticed that the drugs were not absorbed into mitochondria, a key cellular compartment, and HSPs in this compartment were therefore not being blocked. They identified a new HSP inhibitor that can reach every cellular compartment and inhibit all HSPs. Testing in mice showed that this inhibitor effectively triggered death of tumor cells, and therefore shows promise for anti-cancer therapy. The Hsp90 family proteins Hsp90, Grp94, and TRAP1 are present in the cell cytoplasm, endoplasmic reticulum, and mitochondria, respectively; all play important roles in tumorigenesis by regulating protein homeostasis in response to stress. Thus, simultaneous inhibition of all Hsp90 paralogs is a reasonable strategy for cancer therapy. However, since the existing pan-Hsp90 inhibitor does not accumulate in mitochondria, the potential anticancer activity of pan-Hsp90 inhibition has not yet been fully examined in vivo. Analysis of The Cancer Genome Atlas database revealed that all Hsp90 paralogs were upregulated in prostate cancer. Inactivation of all Hsp90 paralogs induced mitochondrial dysfunction, increased cytosolic calcium, and activated calcineurin. Active calcineurin blocked prosurvival heat shock responses upon Hsp90 inhibition by preventing nuclear translocation of HSF1. The purine scaffold derivative DN401 inhibited all Hsp90 paralogs simultaneously and showed stronger anticancer activity than other Hsp90 inhibitors. Pan-Hsp90 inhibition increased cytotoxicity and suppressed mechanisms that protect cancer cells, suggesting that it is a feasible strategy for the development of potent anticancer drugs. The mitochondria-permeable drug DN401 is a newly identified in vivo pan-Hsp90 inhibitor with potent anticancer activity

    Cochlear Implantation after Bilateral Transverse Temporal Bone Fractures

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    Patients deafened by a severe head injury are rarely encountered. We report a case of a 65-yr-old man with bilateral transverse temporal bone fractures due to head injury. He underwent cochlear implant and achieved a satisfactory auditory rehabilitation. Imaging studies of temporal bone before performing a cochlear implantation provide important information on a patient with bilateral temporal bone fractures. Cochlear implantations with careful planning in such a patient may be a very effective method for aural rehabilitation

    Optimal collimator rotation based on the outline of multiple brain targets in VMAT

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    Background The aim of this study was to investigate the dosimetric quality in volumetric modulated arc therapy (VMAT) plans with optimal collimator angles that can represent the outline of multiple brain targets. Methods Twenty patients with multiple target volumes in the brain cases were selected retrospectively. To better represent the outline of the multiple brain targets, four conformal arc plans were generated for each patient using one full arc with four collimator settings. The optimal collimator angles calculated from the integrated multi-leaf collimator (MLC) aperture that had the smallest aperture size for certain collimator settings of the conformal arc plan were selected. VMAT plans with the optimal collimator angles with angular sections of 40° and 60° (Colli-VMAT (40°), Colli-VMAT (60°)) were generated, followed by evaluation of field sizes, dose-volumetric parameters and total monitor units (MUs). Results Patient-averaged values of field sizes for Colli-VMAT (40°) (111.5 cm2) were lowest and 1.3 times smaller than those for Std-VMAT (143.6 cm2). Colli-VMAT plans improved sparing of most normal organs but for brain stem and left parotid gland. For the total MUs, the averaged values obtained with the Colli-VMAT (40°) (390 ± 148 MU) were smaller than those obtained with the Std-VMAT (472 ± 235 MU). Conclusions The Colli-VMAT plans with smaller angular sections could be suitable in the clinic for multiple brain targets as well as for irregularly shaped targets. Determination of the optimal collimator rotation generally showed good normal tissue sparing and MU reduction for multiple brain targets.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2017R1D1A1B03036093) and by a grant from the National R&D Program for Cancer Control, Ministry of Health and Welfare, Republic of Korea (HA16C0025)

    Two-gap and paramagnetic pair-breaking effects on upper critical field of SmFeAsO0.85_{0.85} and SmFeAsO0.8_{0.8}F0.2_{0.2} single crystals

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    We investigated the temperature dependence of the upper critical field [Hc2(T)H_{c2}(T)] of fluorine-free SmFeAsO0.85_{0.85} and fluorine-doped SmFeAsO0.8_{0.8}F0.2_{0.2} single crystals by measuring the resistive transition in low static magnetic fields and in pulsed fields up to 60 T. Both crystals show that Hc2(T)H_{c2}(T)'s along the c axis [Hc2c(T)H_{c2}^c(T)] and in an abab-planar direction [Hc2ab(T)H_{c2}^{ab}(T)] exhibit a linear and a sublinear increase, respectively, with decreasing temperature below the superconducting transition. Hc2(T)H_{c2}(T)'s in both directions deviate from the conventional one-gap Werthamer-Helfand-Hohenberg theoretical prediction at low temperatures. A two-gap nature and the paramagnetic pair-breaking effect are shown to be responsible for the temperature-dependent behavior of Hc2cH_{c2}^c and Hc2abH_{c2}^{ab}, respectively.Comment: 21 pages, 8 figure
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