• 제목/요약/키워드: Chandra

검색결과 426건 처리시간 0.028초

Effects of eye dominance on shade matching and color perception among the dentist population

  • Pattnaik Kalyani;Kannan Subiksha;Amit Jena;Govind Shashirekha;Saumyakanta Mohanty;Gaurav Sharma
    • Restorative Dentistry and Endodontics
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    • 제48권4호
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    • pp.40.1-40.8
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    • 2023
  • Objectives: The purpose of this study was to evaluate the influence of eye dominance on color perception, and shade matching. Materials and Methods: A total of 104 participants were selected for the study. There were 3 groups: Group I: 3rd and 4th year dental students and interns (n = 40); Group II: postgraduates (n = 34); Group III: senior residents and faculty members (≥ 6 years of clinical experience) (n = 30). All participants were evaluated for congenital color blindness with Ishihara plates, their dominant eye with Mile's test, and their color perception with the Farnsworth-Munsell 100 hue test. The shade guide test was used for shade matching with a second corresponding set of Vitapan classical shade guides. Results: The results of Mile's test revealed that 60.6% were right-eye dominant and 39.4% were left-eye dominant. There was a statistically significant difference among all participants between the dominant eye and the non-dominant eye in shade matching. Conclusions: The dominant eye has a positive effect on shade matching and the ability to match shades becomes better with an increase in clinical experience.

Management of maxillofacial injuries in bear mauling cases: a review of 20 cases

  • Kar, Indu Bhusan;Chopda, Prashant Dilip;Mishra, Niranjan;Sethi, Alok Kumar;Mahavoi, Bikas Ranjan
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제42권1호
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    • pp.13-19
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    • 2016
  • Objectives: As the craniofacial and neck regions are prime areas of injury in bear attacks, the careful management of soft and hard tissue injuries and selection of reconstructive options is of the utmost importance. This study will review the incidence and patterns of bear mauling in eastern India reported to our department and the various modalities used for their treatment over a period of 7 years. It also documents the risks of infection in bear mauling cases and the complications that have occurred. Materials and Methods: Twenty cases were treated over the study period. Cases were evaluated for soft and hard tissue injuries including tissue loss and corresponding management in the craniofacial region. Cases were also evaluated for other associated injuries, organ damage and related complications. Results: Various modalities of treatment were used for the management of victims, ranging from simple primary repairs to free tissue transfers. Simple primary repairs were done in 75% of cases, while the management of the injured victims required reconstruction by local, regional or distant flaps in 25%. Free tissue transfers were performed in 15% of cases, and no cases of wound infection were detected in the course of treatment. Conclusion: Knowledge of various reconstructive techniques is essential for managing maxillofacial injuries in bear mauling cases. Modern reconstructive procedures like free tissue transfer are reliable options for reconstruction with minimal co-morbidity and dramatic improvement in treatment outcomes.

Absence of 185delAG and 6174delT Mutations among Breast Cancer Patients of Eastern India

  • Chakraborty, Abhijit;Banerjee, Debolina;Basak, Jayasri;Mukhopadhyay, Ashis
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권17호
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    • pp.7929-7933
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    • 2015
  • Background: The incidence of breast cancer in India is on the rise and is rapidly becoming the number one cancer in females, pushing the cervical cancer to the second position. Most of the predisposition to hereditary breast and ovarian cancer has been attributed to inherited defects in two tumor suppressor genes BRCA1 and BRCA2. Alterations in these genes have been reported in different populations, some of which are population-specific mutations showing founder effects. Two specific mutations in the BRCA1 (185delAG) and BRCA2 (6174delT) genes have been reported to be of high prevalence in different populations. The aim of this study was to estimate the carrier frequency of 185delAG and 6174delT mutations in eastern Indian breast cancer patients. Materials and Methods: We selected 231 histologically confirmed breast cancer patients from our tertiary cancer care center in eastern India. Family history was obtained by interview or a self-reported questionnaire. The presence of the mutation was investigated by allele specific duplex/multiplex-PCR on genomic DNA extracted from peripheral blood. Results: A total of 231 patients (age range: 26-77 years), 130 with a family history and 101 without were screened. The two founder mutations 185delAG in BRCA1 and 6174delT in BRCA2 were not found in any of the subjects. This was confirmed by molecular analysis. Conclusions: Our findings suggest that these BRCA mutations may not have a strong recurrent effect on breast cancer among the eastern Indian population. The contribution of these founder mutations to breast cancer incidence is probably low and could be limited to specific subgroups. This may be particularly useful in establishing further pre-screening strategies.

Detection Probabilities of the X-ray Point Sources in X-ray Extended Sources

  • Kim, Min-Sun;Kim, Eun-Hyeuk
    • 천문학회보
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    • 제35권2호
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    • pp.33.2-33.2
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    • 2010
  • Galaxy clusters are known to be very bright in X-ray and contain a large number of X-ray point sources within the X-ray emission. However, due to the fluctuations of the X-ray emission, it is very difficult to detect faint X-ray sources and to extract accurately the photometric properties of the X-ray point sources in galaxy clusters. In addition, the most X-ray telescopes show spatially varying point spread function (PSF) and suffer from severe vignetting. The Chandra Archival Survey of Galaxy Clusters project is a wide-area ($\sim40deg^2$) survey of serendipitous Chandra X-ray sources in galaxy cluster fields, containing ~58,000 X-ray point sources in ~800 Chandra ACIS observations of ~600 galaxy clusters. This project aim to investigate the density environmental effects on the physical properties of the X-ray point sources, comparing physical properties of the X-ray point sources in galaxy clusters to those in typical fields. To utilize the sensitivity and detection probability of the X-ray point sources in galaxy clusters, we perform extensive Monte-Carlo simulations. In this poster, we compare the detection probability of the X-ray point sources in galaxy clusters to that of typical fields, and discuss quantitatively the difference between them.

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CHANDRA X-RAY OBSERVATIONS OF EARLY TYPE GALAXIES

  • KIM DONG-WOO
    • 천문학회지
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    • 제36권3호
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    • pp.213-222
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    • 2003
  • We review recent observational results on early type galaxies obtained with high spatial resolution Chandra data. With its unprecedented high spatial resolution, Chandra reveals many intriguing features in early type galaxies which were not identified with the previous X-ray missions. In particular, various fine structures of the hot ISM in early type galaxies are detected, for example, X-ray cavities which are spatially coincident with radio jets/lobes, indicating the interaction between the hot ISM and radio jets. Also point sources (mostly LMXBs) are individually resolved down to Lx = a few x $10^{37}\;erg\;sec^{-1}$ and it is for the first time possible to unequivocally investigate their properties and the X-ray luminosity function. After correcting for incompleteness, the XLF of LMXBs is well reproduced by a single power law with a slope of -1.0 - -1.5, which is in contrast to the previous report on the existence of the XLF break at Lx, Eddington = 2 x $10^{38}\;erg\;sec^{-1}$ (i.e., Eddington luminosity of a neutron star binary). Carefully considering both detected and undetected, hidden populations of point sources we further discuss the XLF of LMXBs and the metal abundance of the hot ISM and their impact on the properties of early type galaxies.

Chandra Archival Survey of Galaxy Clusters: Surface Photometry of Diffuse X-ray Emission

  • 김은혁;김민선
    • 천문학회보
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    • 제37권2호
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    • pp.77.2-77.2
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    • 2012
  • We have studied the physical properties of X-ray point sources in galaxy clusters for years based on the archival observations using the most sophisticated space X-ray observatory, Chandra X-ray Observatory. Because the ultimate goal of the study is comparing the physical properties of X-ray point sources found in galaxy clusters to those in X-ray blank fields; blank fields are the regions in the sky where any noticeable cosmic diffuse X-ray emission is not observed, an important key issue regarding this study is picking out the point sources related with galaxy clusters. However we do not have red-shift information of all the X-ray point sources. Therefore as a first order approximation we will consider the point sources with smaller projected cluster-centric distance than the adopted size of galaxy clusters. As a first step of this study we perform X-ray surface photometry of ~600 galaxy clusters based on ~800 Chandra ACIS observations. We carefully investigate the radial structures of diffuse X-ray emission in 3 different energy bands. Based on the highly accurate surface photometry we determine the characteristic size of diffuse X-ray emission (i.e., the boundary of X-ray emission). We also investigate the cosmological evolution of this characteristic size of galaxy clusters. General discussion regarding the two dimensional morphology of galaxy clusters will be presented.

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Chandra Archival Survey of Galaxy Clusters: X-ray Point Sources in Cool-core and Non-cool-core Clusters

  • 김민선;김은혁
    • 천문학회보
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    • 제37권2호
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    • pp.78.1-78.1
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    • 2012
  • We have studied the physical properties of X-ray point sources in galaxy clusters using ~600 Chandra archival observations. The goal of this study is to investigate the density environmental effects on the physical properties of X-ray point sources by comparing the properties of X-ray point sources in galaxy clusters to those in typical blank fields. In this presentation, we show the nature of X-ray point sources which are expected to be related with galaxy clusters with different core properties. Using ~60 galaxy clusters observed with Chandra, we investigate the physical properties of X-ray point sources in cool-core and non-cool-core clusters. The cool-core clusters are known to have short central cooling time, and are characterized by low central entropy, systematic central temperature drops, and a brightest cluster galaxy at the X-ray peak. While the non-cool-core clusters have longer central cooling time, and are characterized by large central entropies and flat or centrally rising temperature profile. We show that how central core properties of galaxy clusters affect on the physical properties of X-ray point sources.

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X-RAY PROPERTIES OF THE PULSAR PSR J0205+6449 IN 3C 58

  • Kim, Minjun;An, Hongjun
    • 천문학회지
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    • 제54권1호
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    • pp.1-8
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    • 2021
  • We report X-ray timing and spectral properties of the pulsar PSR J0205+6449 measured using NuSTAR and Chandra observatories. We measure the pulsar's rotation frequency ν = 15.20102357(9) s-1 and its derivative $\dot{\nu}=-4.5(1){\times}10^{-11}\;s^{-2}$ during the observation period, and model the 2-30 keV on-pulse spectrum of the pulsar with a power law having a photon index Γpsr = 1.07 ± 0.16 and a 2-30 keV flux F2-30 keV = 7.3±0.6 × 10-13 erg cm-2 s-1. The Chandra 0.5-10 keV data are analyzed for an investigation of the pulsar's thermal emission properties. We use thermal and non-thermal emission models to fit the Chandra spectra and infer the surface temperature T∞ and luminosity Lth of the neutron star to be T∞ = 0.5 - 0.8 MK and Lth = 1 - 5 × 1032 erg s-1. This agrees with previous results which indicated that PSR J0205+6449 has a low surface temperature and luminosity for its age of 800-5600 yrs.