scholarly journals Wolf-Rayet Stars in M31

1986 ◽  
Vol 116 ◽  
pp. 231-232
Author(s):  
M.M. Shara ◽  
A.F.J. Moffat
Keyword(s):  
Narrow Band ◽  
Narrow Band Imaging ◽  
Imaging Techniques ◽  
Hii Regions ◽  
Interstellar Extinction ◽  
Limiting Factor ◽  
Main Body ◽  
Weak Line ◽  
The Mean ◽  
Line Equivalent Width

We have completed a survey of the closest giant spiral galaxy beyond our own for Wolf-Rayet stars, using narrow band imaging techniques (cf. Moffat and Shara 1983, Ap. J., 273, 544). About 90% of the main body of M31 has been thoroughly searched to B ≅ 21.5 (MB ≅ −3.5) to a level of emission line equivalent width We(HeII 4686 A) ≳ 60 A. We do not expect interstellar extinction to be a limiting factor in the detection of WR stars, except possibly in the localized neighborhoods of massive HII regions. The mean extinction for stars in the disk is estimated to be AB ≲ 0.9 mag. Although some weak-line WN stars will have escaped detection, the survey should be complete for WC stars.

scholarly journals Narrow band imaging under less-air condition improves the visibility of superficial esophageal squamous cell carcinoma

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Taro Iwatsubo ◽  
Ryu Ishihara ◽  
Yasushi Yamasaki ◽  
Yusuke Tonai ◽  
Kenta Hamada ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Color Change ◽  
Narrow Band ◽  
Narrow Band Imaging ◽  
Endoscopic Observation ◽  
Flat Type ◽  
The Mean ◽  
Visibility Score

Abstract Background The current virtual chromoendoscopy equipment cannot completely detect superficial squamous cell carcinoma (SCC) in the esophagus, despite its development in the recent years. Thus, in this study, we aimed to elucidate the appropriate air volume during endoscopic observation to improve the visibility of esophageal SCC. Methods This retrospective study included a total of 101 flat type esophageal SCCs identified between April 2017 and January 2019 at the Department of Gastrointestinal Oncology, Osaka International Cancer Institute. Video images of narrow band imaging (NBI) under both less-air and standard-air conditions were recorded digitally. Videos were evaluated by five endoscopists. Relative visibility between less-air and standard-air conditions of the brownish area, brownish color change of the epithelium, and dilated intrapapillary capillary loop (IPCL) were graded as 5 (definitely better under less-air condition) to 1 (definitely worse under less-air condition), with 3 indicating average visibility (equivalent to standard-air observation). Results The mean (standard deviation) visibility score of the brownish area, brownish color change of the epithelium, and dilated IPCLs under less-air condition were 3.94 (0.58), 3.73 (0.57), and 4.13 (0.60), respectively, which were significantly better than that under standard-air condition (p < 0.0001). Esophageal SCC evaluated as ≥ 4 in the mean visibility score of the brownish area, brownish color change of the epithelium, and dilated IPCLs accounted for 50% (51/101 lesions), 34% (34/101 lesions), and 67% (68/101 lesions), respectively. Conclusions The present results suggested that NBI with less air might improve the visibility of flat type esophageal SCC compared with NBI with standard air. Less-air NBI observation may facilitate the detection of flat type esophageal SCC. Trial registration The present study is a non-intervention trial.

scholarly journals Narrow-Band Imaging Improves Detection of Colorectal Peritoneal Metastases: A Clinical Study Comparing Advanced Imaging Techniques

2018 ◽  
Vol 26 (1) ◽  
pp. 156-164 ◽  
Author(s):  
Nina Roelie Sluiter ◽  
Stijn Lucas Vlek ◽  
Arthur Randolph Wijsmuller ◽  
Henk Thijs Brandsma ◽  
Henrica Cornelia Wilhelmina de Vet ◽  
...  
Keyword(s):  
Clinical Study ◽  
Narrow Band ◽  
Narrow Band Imaging ◽  
Imaging Techniques ◽  
Peritoneal Metastases ◽  
Advanced Imaging

scholarly journals VLT/FORS Surveys of Wolf-Rayet Stars in the Nearby Universe

2007 ◽  
Vol 3 (S250) ◽  
pp. 327-332
Author(s):  
Lucy J. Hadfield ◽  
Paul A. Crowther
Keyword(s):  
Local Group ◽  
Narrow Band ◽  
Dwarf Galaxy ◽  
Narrow Band Imaging ◽  
Interstellar Extinction ◽  
Spectroscopic Studies ◽  
Order Of Magnitude ◽  
Low Metallicity ◽  
Massive Clusters ◽  
Blue Compact Dwarf Galaxy

AbstractWe present results from a series of VLT/FORS narrow-band imaging and spectroscopic surveys of Wolf-Rayet (WR) stars in nearby spiral galaxies and compare observed populations in high- and low metallicity environments. The metal-rich galaxy M 83 is seen to host an exceptional WR content, with over 1000 WR stars being detected. N(WC)/N(WN) ~ 1.2 and late-type WC subtypes dominate the WC population. At low metallicity, ~100 stars has been identified within NGC 1313, with N(WC)/N(WN) ~ 0.5. In contrast to M83, the WC population of NGC 1313 comprises solely early subtypes plus a WO star (the first WO star to be identified beyond the Local Group). Consequently, the dominant WC subtype may serve as a crude metallicity diagnostic for WR galaxies.In addition, the WR content of the blue compact dwarf galaxy NGC 3125 is examined. Previous UV and optical spectroscopic studies of knot A in NGC 3125 derive WR populations which differ by more than an order of magnitude. New VLT observations and archival HST spectroscopy reconcile this discrepancy via the use of LMC WR spectral templates and a reduced nebular-derived interstellar extinction. Empirical N(WR)/N(O) ratios for clusters within NGC 3125 are a factor of two higher than evolutionary synthesis predictions but are consistent with those observed for other young massive clusters.

THE VALUE OF NARROW BAND IMAGING ENDOSCOPY IN DIAGNOSIS OF HYPOPHARYNGEAL AND LARYNGEAL CANCER AND FOLLOWING - UP POST TREATMENT

2018 ◽  
Vol 8 (6) ◽  
pp. 114-122
Author(s):  
Thong Le Chi ◽  
Thanh Dang ◽  
Nam Tran Phuong
Keyword(s):  
Laryngeal Cancer ◽  
Narrow Band ◽  
Narrow Band Imaging ◽  
Hypopharyngeal Cancer ◽  
Post Treatment ◽  
Predominant Type ◽  
Mucosal Edema ◽  
Contrast Medium Injection ◽  
The Mean ◽  
Type V

Background: To evaluate the value of narrow band imaging (NBI) endosocopy in diagnosis of hypopharyngeal and laryngeal cancer and following – up post treatment. Material and methods: A total of 75 patients included 36 patients with hypopharyngeal cancer and 39 patients with laryngeal cancer who had diagnosed at Department of Otoloryngology – Hue Central Hospital from 5/2017 to 5/2018. A prospective cohort study was conducted. Results: The age group 51 - 60 years occurred most often, 33.3%, the mean age was 62.1 ± 13.4. The UICC stage III was 65.3%. Tumor was in ulcerlarative and infiltrate form (89.4%), edema and inflammation of magrin tumor (41.3%), invasive (58.7%). Intrapapillary capillary loops – IPCL - type V was predominant, type V-n was 46.7%. The tumor with IPCL type V-n had strong enhancement (51.3%) and moderate enhancement (44.4%) after contrast medium injection on CT scan. One month after treatment, there were 33.3% of tumor – free, 53.7% of mucosal edema and 13% tumor size-decreasing on NBI image. Conclusion: NBI endoscopy is an useful tool for diagnosing of hypopharyngeal and laryngeal cancer and following – up post treatment. Key words: narrow band imaging endoscopy, hypopharyngeal cancer, laryngeal cancer

scholarly journals NGC 613: Nuclear Region Narrow Band Imagery

1989 ◽  
Vol 134 ◽  
pp. 474-475
Author(s):  
H. A. Dottori
Keyword(s):  
Central Region ◽  
Narrow Band ◽  
Hii Regions ◽  
Pure Line ◽  
Integration Time ◽  
Absolute Calibration ◽  
Nuclear Region ◽  
Gas Emission ◽  
Solar Metallicity ◽  
The Mean

The peculiar nuclear region (Hummel et al., 1987) of the southern barred spiral NGC613 has been imaged with a CCD attached to the 90 cm CTIO reflector and integration time of one hour, using narrow band filters at Hα, Hβ, [OIII], [OII] and continua at 3765 Å(C[OII]), 5200 Å(CEβ) and 6476 Å(CHα), which allow to obtain pure line frames. Stone and Baldwin (1983) spectrophotometric standards have been observed for absolute calibration. The CHα (fig. 1) and CHβ (fig. 2) images show the well known 2 blobs structure, the SE of which is the nucleus. The ratio of both frames reveals an up to now unknown ring like structure (fig. 8) of 1400 × 2300 pc. The monochromatic color c(CHβ-CHα) reach 0.6 mag on the ring and 0.0 to 0.2 mag in its inner zone, where most of the gas emission is produced. The ratio Hα/Hβ (fig. 7) shows that the ring is practically absorption free, and that the dust is strongly concentrated in a zone of 400 pc, shifted 500 pc to the N of the nucleus, absorving up to 6 mag. in Hβ. Comparison with star monochromatic colors (O'Connell, 1973) lead to conclude that the ring colour is produced by red stars, with a mean spectral type G8 to K1, while in the central region it is A5 to F0. This ring is probably similar to that of HII regions observed in NGC 1097 (Osmer et al. 1974), but with the ionizing stars having evolved to RSG. The Hα pattern (fig. 3) presents only one maximum, displaced about 300 pc to the SE of the nucleus, being the weakest isophotes distorted to the W. The Hβ one (fig. 4) shows also one maximum, but the isodensities are elongated due to the extinction. The [OII] (fig. 6) shows a two blob like structure; and the [OIII], with the richest feature distribution, shows emission minima coincident with the [OII] blobs. The mean Hα/Hβ ratio is about 3.9, but mean extinction correction can be meaningless due to the distribution of dust. The ratios [OIII]/Hβ = 0.47 and [OII]/Hβ = 0.27, when compared with Stasińska's (1982) photoionization models, indicate higher than solar metallicity and Teff ≈ 40,000K for the ionizing source.

Computer-assisted diagnosis of early esophageal squamous cell carcinoma using narrow-band imaging magnifying endoscopy

Endoscopy ◽  
2018 ◽  
Vol 51 (04) ◽  
pp. 333-341 ◽  
Author(s):  
Yuan-Yuan Zhao ◽  
Di-Xiu Xue ◽  
Ya-Lei Wang ◽  
Rong Zhang ◽  
Bin Sun ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Esophageal Squamous Cell Carcinoma ◽  
Gold Standard ◽  
Narrow Band ◽  
Narrow Band Imaging ◽  
Magnifying Endoscopy ◽  
Computer Assisted ◽  
Double Labeling ◽  
The Mean ◽  
Assisted Diagnosis

Abstract Background We developed a computer-assisted diagnosis model to evaluate the feasibility of automated classification of intrapapillary capillary loops (IPCLs) to improve the detection of esophageal squamous cell carcinoma (ESCC). Methods We recruited patients who underwent magnifying endoscopy with narrow-band imaging for evaluation of a suspicious esophageal condition. Case images were evaluated to establish a gold standard IPCL classification according to the endoscopic diagnosis and histological findings. A double-labeling fully convolutional network (FCN) was developed for image segmentation. Diagnostic performance of the model was compared with that of endoscopists grouped according to years of experience (senior > 15 years; mid level 10 – 15 years; junior 5 – 10 years). Results Of the 1383 lesions in the study, the mean accuracies of IPCL classification were 92.0 %, 82.0 %, and 73.3 %, for the senior, mid level, and junior groups, respectively. The mean diagnostic accuracy of the model was 89.2 % and 93.0 % at the lesion and pixel levels, respectively. The interobserver agreement between the model and the gold standard was substantial (kappa value, 0.719). The accuracy of the model for inflammatory lesions (92.5 %) was superior to that of the mid level (88.1 %) and junior (86.3 %) groups (P < 0.001). For malignant lesions, the accuracy of the model (B1, 87.6 %; B2, 93.9 %) was significantly higher than that of the mid level (B1, 79.1 %; B2, 90.0 %) and junior (B1, 69.2 %; B2, 79.3 %) groups (P < 0.001). Conclusions Double-labeling FCN automated IPCL recognition was feasible and could facilitate early detection of ESCC.

Photo-electric Hβ and uvby photometry

1966 ◽  
Vol 24 ◽  
pp. 170-180
Author(s):  
D. L. Crawford
Keyword(s):  
Narrow Band ◽  
Line Strength ◽  
Interference Filter ◽  
B Stars ◽  
Relative Line ◽  
The Mean ◽  
F Stars ◽  
Two Parameters ◽  
Filter Photometry ◽  
The Continuum

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

NARROW BAND IMAGING COMO MÉTODO ALTERNATIVO PARA LA DETECCIÓN Y CARACTERIZACIÓN DE LOS FOCOS DE CRIPTAS ABERRANTES

Endoscopy ◽  
2011 ◽  
Vol 43 (12) ◽  
Author(s):  
M López-Cerón ◽  
M Jimeno ◽  
C Rodríguez de Miguel ◽  
M Zabalza ◽  
V Alonso-Espinaco ◽  
...  
Keyword(s):  
Narrow Band ◽  
Narrow Band Imaging
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