6 research outputs found

    X-ray Astronomy from the Lunar Surface

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    Motivated by efforts to return humanity to the Moon, three cases are reviewed for X-ray astronomy from the lunar surface: (1) Facilitation of ambitious engineering designs including high throughput telescopes, long focal length optics and X-ray interferometery; (2) Occultation studies and the gain they enable in astrometric precision; (3) Multimessenger time-domain coordinated observations. The potential benefits of, and challenges presented by, operating from the Moon are discussed. Some of these cases have relatively low mass budgets and could be conducted as early pathfinders, while others are more ambitious and will likely need to await improvements in technology or well-developed lunar bases.Comment: Invited peer-reviewed article (author version) for a theme issue of Phil. Trans. R. Soc. A on 'Astronomy from the Moon: the next decades (Part 2)' eds. I. Crawford, M. Elvis, J. Silk and J. Zarnecki. Comments/collaboration welcom

    An open access database for the evaluation of heart sound algorithms

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    This is an author-created, un-copyedited version of an article published in Physiological Measurement. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/0967-3334/37/12/2181In the past few decades, analysis of heart sound signals (i.e. the phonocardiogram or PCG), especially for automated heart sound segmentation and classification, has been widely studied and has been reported to have the potential value to detect pathology accurately in clinical applications. However, comparative analyses of algorithms in the literature have been hindered by the lack of high-quality, rigorously validated, and standardized open databases of heart sound recordings. This paper describes a public heart sound database, assembled for an international competition, the PhysioNet/Computing in Cardiology (CinC) Challenge 2016. The archive comprises nine different heart sound databases sourced from multiple research groups around the world. It includes 2435 heart sound recordings in total collected from 1297 healthy subjects and patients with a variety of conditions, including heart valve disease and coronary artery disease. The recordings were collected from a variety of clinical or nonclinical (such as in-home visits) environments and equipment. The length of recording varied from several seconds to several minutes. This article reports detailed information about the subjects/patients including demographics (number, age, gender), recordings (number, location, state and time length), associated synchronously recorded signals, sampling frequency and sensor type used. We also provide a brief summary of the commonly used heart sound segmentation and classification methods, including open source code provided concurrently for the Challenge. A description of the PhysioNet/CinC Challenge 2016, including the main aims, the training and test sets, the hand corrected annotations for different heart sound states, the scoring mechanism, and associated open source code are provided. In addition, several potential benefits from the public heart sound database are discussed.This work was supported by the National Institutes of Health (NIH) grant R01-EB001659 from the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and R01GM104987 from the National Institute of General Medical Sciences.Liu, C.; Springer, DC.; Li, Q.; Moody, B.; Abad Juan, RC.; Li, Q.; Moody, B.... (2016). An open access database for the evaluation of heart sound algorithms. Physiological Measurement. 37(12):2181-2213. doi:10.1088/0967-3334/37/12/2181S21812213371

    Peripheral Microvascular Abnormalities Detected by Wide-Field Fluorescein Angiography in Eyes with Branch Retinal Vein Occlusion.

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    Purpose: To evaluate the location of microvascular abnormalities using wide-field fluorescein angiography (WFFA) and investigate the impact on visual outcomes in eyes with branch retinal vein occlusion (BRVO). Methods: Forty of 39 patients (24 male and 15 female, average age of 71 years) were retrospectively reviewed. One patient had BRVO bilaterally. WFFA was performed in all patients to evaluate perfusion status and detect microvascular abnormalities. The areas on WFFA images were divided into three groups; Zone 1: posterior pole, Zone 2: mid periphery, and Zone 3: far periphery to document the presence of microvascular abnormalities. Scatter retinal photocoagulation (PC) was performed for retinal neovascularization (NV) and/or widespread NPAs. Results: The incidence of microvascular abnormalities in Zone 3 was significantly (P<0.0001) less than those in Zone 1 and Zone 2. The presence of larger NPAs in Zone 1, but not Zone 3, was associated with the incidence of NV and vitreous hemorrhage. Both the presence of peripheral lesions and application of PC did not affect the visual outcomes. Conclusion: The presence of peripheral abnormalities or scatter PC for NPAs did not affect the visual outcomes in eyes with BRVO

    Improved clonality detection in B-cell lymphoma using a semi-nested modification of the BIOMED-2 PCR assay for IGH rearrangement: A paraffin-embedded tissue study

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    The BIOMED-2 PCR protocol for targeting the IGH gene is widely employed for detecting clonality in B-cell malignancies. Unfortunately, the detection of clonality with this method is not very sensitive when paraffin sections are used as a DNA source. To increase the sensitivity, we devised a semi-nested modification of a JH consensus primer. The clonality detection rates of three assays were compared: the standard BIOMED-2, BIOMED-2 assay followed by BIOMED-2 re-amplification, and BIOMED-2 assay followed by semi-nested BIOMED-2. We tested more than 100 cases using paraffin-embedded tissues of various B-cell lymphomas, and found that the clonality detection rates with the above three assays were 63.9%, 79.6%, and 88.0%, respectively. While BIOMED-2 re-amplification was significantly more sensitive than the standard BIOMED-2, the semi-nested BIOMED-2 was significantly more sensitive than both the standard BIOMED-2 and BIOMED-2 re-amplification. An increase in sensitivity was observed in all lymphoma subtypes examined. In conclusion, tumor clonality may be detected in nearly 90% of B-cell lymphoma cases with semi-nested BIOMED-2. This ancillary assay may be useful when the standard BIOMED-2 fails to detect clonality in histopathologically suspected B-cell lymphomas

    Structural and Functional Analyses of Retinal Ischemia in Eyes with Retinal Vein Occlusion: Relationship with Macular Edema or Microaneurysm Formation

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    Purpose: To study the structural and functional changes of retinal ischemia and investigate their association with macular edema (ME) or microaneurysm (MA) formation in eyes with retinal vein occlusion (RVO). Methods: Sixty eyes of 30 patients (27 eyes with branch [b]RVO, 3 with central RVO, and 30 fellow eyes) were retrospectively reviewed. Optical coherence tomography (OCT), OCT angiography (OCTA), and microperimetry were performed simultaneously to measure retinal thickness and sensitivity. The presence of ME or MA was also assessed using OCT and fluorescein angiography. Results: The mean retinal sensitivity in the nonperfused areas (NPAs) deteriorated, and this was significantly (r = –0.379, p = 0.0391*) and inversely correlated with duration from disease onset. ME and MA were unlikely to be observed around the area where the retinal sensitivity decreased. In the NPAs, the mean retinal thickness of the superficial capillary plexus (SCP) (p < 0.0001), deep capillary plexus (DCP) (p = 0.0323), and outer retina (p = 0.0008) were significantly thinner than those in the fellow eyes, respectively. Multivariate regression analysis revealed that the thicknesses of the DCP (β: 0.3107, p = 0.0007) and outer retina (β: 0.3482, p = 0.0001) were the independent correlative factors of the retinal sensitivity, but that SCP thickness was not. Conclusion: Deep retinal thinning in NPAs was correlated significantly with a decreased retinal sensitivity, which might be a negative predictor of ME and MA in eyes with RVO

    Microvascular Abnormalities on Optical Coherence Tomography Angiography in Macular Edema Associated With Branch Retinal Vein Occlusion

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    PURPOSE: To determine the ability of optical coherence tomography (OCT) angiography to image the microvascular structures compared with fluorescein angiography (FA) in patients with macular edema associated with branch retinal vein occlusion (BRVO).DESIGN: Retrospective, observational, consecutive case series.METHODS: Twenty-eight eyes of 27 patients (14 men, 13 women; mean age, 68.4 years) with macular edema associated with BRVO were enrolled.Simultaneous OCT angiography and FA were performed in all patients to evaluate the microvascular abnormalities and non-perfused areas.RESULTS: OCT angiography detected non-perfused areas in 28 eyes and FA in 18 eyes. The respective findings of superficial capillary telangiectasias by OCT angiography and FA were 13 and 11 eyes, for deep capillary telangiectasias 28 eyes and 11 eyes, for collateral vessels 18 eyes and 16 eyes, and for microaneurysms 13 eyes and 14 eyes. OCT angiography facilitated differential layer analysis of microaneurysms and collaterals in the retina.CONCLUSIONS: OCT angiography can visualize microvascular abnormalities equally well or better than FA in eyes with BRVO. Multimodal imaging using OCT angiography and FA can be a powerful tool to evaluate the pathology in BRVO
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